Roles of gut and oral microbiota in methamphetamine-induced multi-organ toxicity

Abstract

Methamphetamine (METH) is an illicit stimulant that is in widespread use worldwide. Repeated intake of METH can lead to addiction and multiple-organ damage, which has become a globalized problem. However, the mechanism of METH toxicity remains unclear. The gut and oral microbiota and their metabolites have an impact on host behavior, metabolism, nutrition, and immune response. The available research find that METH not only disrupts the intestinal microbiota, but also alters the metabolites produced by the intestinal microbiota, such as reducing the levels of short-chain fatty acids (SCFAs), indole derivatives and inosine, and increasing the levels of trimethylamine N-oxide and lipopolysaccharide (LPS). The gut microbiota and their metabolites can participate in mediating METH-induced multi-organ toxicity via the intestinal immune interface and the gut-organ axis, thereby regulating processes such as oxidative stress, inflammatory responses, and mitochondrial damage. Concurrently, therapeutic approaches targeting the affected gut microbiota (including probiotic, microbiota transplantation, SCFAs, and indole derivatives) have also been demonstrated to effectively mitigate damage caused by METH abuse. The objective of this review is to establish a link between METH and the microbiota from the gut and oral cavity, based on the available evidence, to gain insight into the potential bidirectional roles of the gut and oral microbiota in METH addiction and METH-related multi-organ toxicity, and to develop future therapeutic strategies.

Graphical Abstract

Methamphetamine (METH) mediates multi-organ toxic damage through the "microbe-gut-organ axis." It has been established that microorganisms and their metabolites can regulate the pathophysiological processes of diseases in extra-intestinal organs. METH induces gut dysbiosis, allowing inflammatory factors and bioactive substances to enter the circulatory system and affect distant organs. This ultimately disrupts the immune response, metabolic state, and homeostasis of these organs. Meanwhile, these organs can reciprocally influence the gut, indicating that this regulatory axis is bidirectional.

Introduction

Methamphetamine (METH), a potent illicit psychostimulant, is the subject of widespread abuse around the world (UNODC 2024). METH, first synthesized in 1919 and commercially used in 1938 (Prakash et al. 2017), has been employed in the treatment of attention deficit hyperactivity disorder, and severe obesity (Gonzales et al. 2010; Jayanthi et al. 2021). METH is commonly administered via multiple routes, including oral ingestion, intranasal insufflation, intravenous injection, and smoking, all of which result in rapid systemic distribution (Moshiri et al. 2020). Upon entering the body, METH is primarily metabolized in the liver predominantly mediated by cytochrome P450 enzymes (such as CYP2D6), resulting in metabolites including amphetamine, 4-hydroxymethamphetamine, norephedrine, hippuric acid, 4-hydroxyamphetamine, and 4-hydroxynorephedrine (Courtney and Ray 2014). Concurrently, the elimination half-life of METH ranges from 8 to 13 h. Notably, the majority (30- 50%) of the parent compound is excreted unchanged in the urine, the rate of which is highly dependent on urinary pH; acidic urine accelerates excretion, while alkaline urine promotes reabsorption (Abbruscato and Trippier 2018; Courtney and Ray 2014). Furthermore, METH’s cellular uptake and extrusion are facilitated by specific membrane transporters (Courtney and Ray 2014; Ramli et al. 2025). Although METH has been used to treat medical conditions, prolonged, uncontrolled use of METH has been shown to induce substance use disorder, which is clinically manifested by persistent drug-seeking behavior and intense craving for METH, despite harmful consequences. Adverse clinical sequelae manifest in multiple organ systems and include neuropsychiatric disorders, cardiovascular pathology, hepatic dysfunction, pulmonary arterial hypertension, periodontitis, and renal impairment. Specific neurological and psychiatric effects of METH include stroke, epileptic seizures, schizophrenia, and psychosis (Jayanthi et al. 2021). The rise in global METH consumption has led to a notable increase in associated medical expenses and substantial social and economic challenges, which has been a severe public problem in the past years (Han et al. 2021; Shao et al. 2020). According to the 2023 World Drug Report from the United Nations Office on Drugs and Crime, METH is probably the most widely used and supplied synthetic stimulant in the world (UNODC 2024). In China, METH is still the most widely used amphetamine-type stimulant, with a total of 455,000 individuals engaging in METH use in 2023, representing approximately 50.8 percent of the estimated total number of drug abusers (OCNNC 2024).

Acute or short-term use of METH can result in increased heart rate, blood pressure, body temperature, and loss of appetite. Long-term or repeated use of METH can lead to infection, malnutrition, paranoia, violent behavior, mental illness, and multiple organ damage (Prakash et al. 2017). Due to its lipophilic nature (Meredith et al. 2005), METH may also cross the blood–brain barrier (BBB), where it may cause neurotoxic effects (Jayanthi et al. 2021; Shrestha et al. 2022). METH exerts an influence on the release of neurotransmitters, such as dopamine, norepinephrine, and serotonin by acting on dopamine transporters and vesicular monoamine transporters, which in turn gives rise to dysfunction and structural damage to the neurons in brain regions, including the ventral tegmental area, the nucleus accumbens, the dorsal striatum, the hippocampus, and the prefrontal cortex (Guo et al. 2022; Jameie et al. 2022; Meng et al. 2020). The above brain changes persist for many years after the cessation of METH use. Furthermore, the long use of METH is associated with the onset of various other adverse health effects, including hepatotoxicity, cardiotoxicity, pulmonary hypertension, gastrointestinal damage (Carlson et al. 2012; Darke et al. 2017; Prakash et al. 2017; Shaerzadeh et al. 2018). In the intestines, METH has been demonstrated to induce damage to the intestinal structure and function (Zhang et al. 2022b; Zhao et al. 2019).

The gut microbiome is defined as a complex, dynamic, and spatially heterogeneous system composed of​ a vast array of microorganisms, which interact with each other and with the host (El-Sayed et al. 2021). The intestinal microbiota is characterized by a state of equilibrium and interdependence, thus establishing a functionally integrated symbiotic partnership with the host. This partnership is characterized by bidirectional metabolic coordination, which is mutually beneficial and plays a pivotal role in a multitude of physiological processes (Jandhyala et al. 2015). Recent advancements in multi-omics methodologies have profoundly impacted the field of microbiome research. The development of molecular profiling systems, next-generation sequencing platforms, and computational biomodelling frameworks has led to a transformative change in the manner by which gut microbial ecosystems are investigated. These innovations have facilitated a shift towards a systems-level analysis of microbiota-host interactomes, representing a significant advancement in our understanding of complex biological systems. Numerous studies have shown that changes in the gut microbiota can affect the physiological and pathological processes of the host and may also lead to the occurrence of a series of diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic diseases, and gastrointestinal diseases (Bajaj 2014; Dalile et al. 2019; Farzi et al. 2018; Haneishi et al. 2023; Tang et al. 2017). Numerous studies have shown that substance abuse can alter the gut microbiota (Caspani et al. 2024; Chivero et al. 2022a; He et al. 2025; Wang et al. 2022d). Evidence has emerged that exposure to ethanol results in an impairment to the homeostasis of the gut microbiota, with studies consistently observing manifestations of structural and metabolic dysbiosis in rodent models and human clinical cohorts (Engen et al. 2015). Furthermore, analogous manifestations have been observed in studies of cocaine, opioids, and METH (Banerjee et al. 2016; Li et al. 2023; Yang et al. 2021c). In addition, alterations in the gut microbiota and its metabolites also take part in the damage of the aforementioned drugs (Angoa-Perez et al. 2020). For instance, drug use can result in gut microbiota dysbiosis, which can disrupt the gut barrier function and trigger inflammatory responses, which may exacerbate multi-organ damage (Chivero et al. 2022b; Mishra et al. 2023; Thomaz et al. 2021; Yang et al. 2022). Therefore, there is the potential for the gut microbiota to exert an important role in METH-induced multi-organ toxicity and abuse.

The majority of previous research has concentrated on the direct toxic mechanisms of METH. Whilst these studies appear to offer a more intuitive understanding of how METH exerts toxic effects on a specific organ; they share a limitation: the direct toxic mechanisms targeting a single organ fail to explain METH's toxic impact on other organs throughout the body. Furthermore, the mutual regulatory interactions among various organ systems within the body are overlooked. However, it is important to note that microbiota may play a significant role in the systemic toxicity of METH across multiple organs. A substantial body of research has demonstrated that the intestines communicate with other organs, including the brain, liver, heart, and so on, through the gut microbiota. The ingestion of METH has been demonstrated to induce intestinal microbial imbalance, which in turn compromises the intestinal barrier and affects the functionality of multiple organs via diverse biological pathways (Aburto and Cryan 2024; Jansen et al. 2021; Li et al. 2022; Ohtani and Hara 2021; Yu et al. 2023). The preceding findings suggest a potential role for gut microbiota in the manifestation of symptoms and organ toxicity induced by METH. Previous reviews have addressed the role of gut microbiota in substance use disorders, but most merely briefly mention alterations in the gut microbiota during METH abuse or potential underlying mechanisms. Alternatively, the focus is on the role of the gut microbiota in METH-induced central nervous system damage (Caspani et al. 2024; Wang et al. 2022d). It is evident that the extant literature provides an incomplete description of the role of the gut and oral microbiota in METH-induced multi-organ damage. This review focuses on the association between METH exposure and the gut and oral microbiota to elucidate the mechanisms of METH-induced damage and identify potential therapeutic strategies for METH addiction and multi-organ toxicity.

Roles and mechanisms of intestinal microbiota in METH-induced multi-organ toxicity and addiction in animal models.

A number of research has demonstrated that exposure to METH leads to increased intestinal permeability and oxidative stress, inducing gastrointestinal inflammation and ischemia (Herr and Caravati 1991). Furthermore, the disruption of intestinal wall integrity may cause the leakage of intestinal contents—including microbiota, toxins, and inflammatory cells—into the circulation, mesenteric lymph nodes, spleen, and liver (Prakash et al. 2017), which in turn leads to systemic inflammation. As shown in Table 1, a substantial body of research has demonstrated that the abuse of METH can result in the triggering of microbial imbalance in both human and animal studies (He et al. 2023a; Liu et al. 2023a; Shen et al. 2020a; Wang et al. 2022b; Yang et al. 2021c). For example, exposure to METH leads to an increase in the proportion of pathogenic microbes (like Ruminococcaceae, Mucispirillum, and Alistipes), while concomitantly resulting in a proportional reduction in beneficial bacterial populations (like Akkermansia, Faecalibaculum, Desulfovibrio, and Anaerostipes) (Chen et al. 2021b; Forouzan et al. 2021; Ning et al. 2017; Qin et al. 2021). METH has been demonstrated to disrupt the gut microbiome, thereby changing the gut microbiota-derived metabolite productions, such as decreases levels of short-chain fatty acids (SCFAs) (Liang et al. 2023a; Zhang et al. 2023b), tryptophan-derived indole derivatives (Wang et al. 2025a), and inosine (Yang et al. 2022), and increases levels of trimethylamine N-oxide (TMAO) (Wang et al. 2025b), and lipopolysaccharides (LPS) (Yang et al. 2023). In addition, the intestinal leakage microbiota induces immune activation through intestinal metabolite-dependent pathways. For instance, when LPS, a component of the cell wall of Gram-negative bacteria, leaks from the intestinal tract, it can cause endotoxemia and systemic inflammation (Wang et al. 2022b).

Table 1.

Summary of gut and oral microbiota in animal and human METH models

Objects	Age /Weight	Sex	Exposure	Microbiota Classification	Microbiota Dysbiosis	METH Damage manifestations and mechanisms	References
C57/BL6J mice gut	Postnatal to day 56	Male	Alternate injections of METH (1 mg/kg, i.p.) for 12 d	Phylum	↑: Deferribacteres	METH addiction	(Wang et al. 2021b)
				Genus	↑: Prevotella
	6–8 weeks	/	Alternate injections of METH (2 mg/kg, i.p.) for 6 d	Family	↑: Eubacteriaceae	Intestinal inflammation and craving	(Wang et al. 2023a)
				Genus	↑: Eubacterium ↓: Alloprevotella, and Akkermansia
	8 weeks	Male	Injection of METH (1 mg/kg, i.p.) for 30 d	Genus	↓: Akkermansia, Anaerovorax, Coprobacter, Enterorhabdus, Erysipelotrichaceae, Staphylococcus, Enterobacter and Aerococcus	Anxiety	(Lu et al. 2023a)
	6–8 weeks	Male	Injection of METH (starting with 1.5 and escalating to 10 mg/kg i.p.) for 8 d [i]	Family	↑: Oscillospiraceae, Rikenellaceae, and Helicobacteraceae ↓: Fusobacteriaceae, and Prevotellaceae	Anxiety-like and depression-like behaviors and intestinal injury	(Chen et al. 2024)
	8–10 weeks	Male	Injections of METH (15 mg/kg, i.p.) for 4 d (twice a day, at 12 h intervals)	Genus	↑: Lactobacillus, Rikenella, Mucispirillum, and norank_f__Desulfovibrionaceae ↓: norank_f__Muribaculaceae, and unclassified_f__Lachnospiracea	Cholestasis, and hepatic inflammation	(Zhang et al. 2022c)
	8–10 weeks	Male	Injections of METH (15 mg/kg, i.p.) for 4 d (twice a day, at 12 h intervals)	Genus	↑: Lactobacillus, Lachnospiraceae_NK4A136_group, Alistipes and Mucispirillum ↓: norank_f_Muribaculaceae, and Faecalibaculum	Colonic inflammation, and anxiety- and depression-like behaviors	(Zhang et al. 2023b)
	18–22 g	Male	Injection of METH (2 mg/kg, i.p.) for 3 d	Genus	↑: Mycoplasma, unclassified_Clostridia, Desulfovibrio, and Turicibacter ↓: unclassified_Atopobiaceae, and Coriobacteriaceae_UCG_002	Craving and hyperactivity	(Zhuang et al. 2024a)
	20–25 g	Male	Injection of METH (5 mg/kg, i.p.) for 21 d	Family	↑: Ruminococcaceae, Rikenellaceae, and Enterobacteriaceae ↓: Bacteroidaceae, and Alcaligenaceae	Anxiety and depression-like behaviors	(Yang et al. 2022)
	8–10 weeks	Male	Injection of METH (2 mg/kg, i.p.) for 5 d	Genus	↑: Bifidobacterium ↑: Lactobacillaceae, norank_f_Ruminococcaceae, Ruminococcaceae_UCG-013, the Lachnospiraceae_NK4A136_group, Lachnospiraceae_UCG-006, norank_f_, unclassified_f_ Lachnospiraceae	Intestinal inflammation	(Zhang et al. 2022b)
	8–10 weeks	Male	Injection of METH (15 mg/kg, i.p.) for 4 d (twice a day at 12 h intervals)	Genus	↑: Roseburia, Lactobacillus, Mucispirillum, Rikenella, norank_f__Erysipelotrichaceae, norank_f__Desulfovibrionaceae, and Bifidobacterium ↓: norank_f__Muribaculaceae, unclassified_f__Lachnospiraceae	Anxiety-like behavior	(Yang et al. 2023)
	6 weeks	Male	Injection of METH (starting with 1.5 and escalating to 10 mg/kg, i.p.) for 8 d	Family	↓: Muribaculaceae, Prevotellaceae, and Lactobacillaceae ↑: Ruminococcaceae, Christensenellaceae, Peptostreptococcaceae, and Enterobacteriaceae	Inflammation in the colonic mucosa	(Wang et al. 2022b)
	8 weeks	Male	Injection of METH (starting with 1.5 and escalating to 4 mg/kg, i.p.) for 17 d [ii]	Genus	↓: Paraprevotella, Escherichia, Adlercreutzia, Brachyspira, Corynebacterium, and Butyricicoccus ↑: Helicobacter, Mucispirillum, Dorea, and Mycoplasma	Neuroinflammation	(Lai et al. 2022a)
	2 months	Male	Injection of METH (1 mg/kg, i.p.) for 7 d	Genus	↓: Oscillibacter, uncultured, Negativibacillus, and Alloprevotella ↑: Faecalibaculum, Enterorhabdus, and Clostridium_sensu_stricto_1	Cognitive dysfunction	(Liang et al. 2023a)
	7 weeks	Male	Injection of METH (10 mg/kg, i.p.) for 7 d	Phylum	↑: Firmicutes	Learning and memory impairment	(Wu et al. 2023)
				Family	↑: Bacteroidaceae, Lachnospiraceae, and Lactobacillaceae
				Genus	↑: Escherichia-Shigella, Bacteroides, and Lactobacillus
	8–9 weeks	Female	Injection of METH (5 mg/kg, i.p.) for 17 d	Phylum	↑: Firmicutes, Verrucomicrobia, and Cyanobacteria ↓: Bacteroidetes, Actinobacteria, and Patescibacteria	Hepatotoxicity	(Li et al. 2024)
	17.8–21.1 g	Male	Alternate injections of either METH (1 mg/kg, i.p.) or saline for 12 d	Phylum	↑: Bacteroidetes, Firmicutes, and Verrucomicrobia	METH addiction	(Wang et al. 2023b)
				Genus	↑: Bacteroides, Akkermansia, Lactobacillus, Alistipes, Parabacteroides, and Helicobacter
				Species	↑: Duncaniella dubosii, Muribaculum intestinale, Akkermansia muciniphila, Muribaculum sp. TLL-A4, and Lactobacillus johnsonii
	6–8 weeks	Male	Injection of METH (15 mg/kg, i.p.) for 4 d (twice a day at 12 h intervals)	Phylum	↑: Firmicutes ↓: Bacteroidota	Hepatic injuries	(Zhang et al. 2024a)
				Genus	↑: Lactobacillus ↓: norank_f_Muribaculaceae
	18–25 g	Female	Injection of METH (5 mg/kg, i.p.) (four times a day) for 1, 2, or 7 d	Phylum	↑: Mucispirillum, and Enterobacteriales	Disruption of gut microbiota	(Angoa-Perez et al. 2020)
BALB/c mice gut	8–10 weeks	Male	Injection of METH (starting with 1.5 and escalating to 10 mg/kg, i.p.) for 8 d	Genus	↑:Lachnospiraceae_NK4A136_group	Reproductive toxicity	(Liu et al. 2024b)
	6–8 weeks	Male	Injection of METH (starting with 1.5 and escalating to 10 mg/kg, i.p.) for 8 d	Genus	↑: Lactobacillus and Bifidobacterium ↓: norank_f_Muribaculaceae, Alistipes, Enterorhabdus and Bacteroides	Cardiac injury	(Liu et al. 2023b)
	6–8 weeks	Male	Injection of METH (starting with 1.5 and escalating to 10 mg/kg, i.p.) for 8 d	Genus	↑: Alistipes, Parasutterella, Bifidobacterium, Blautia, Anaerotruncus, Acinetobacter, and Escherichia-Shigella ↓: Lactobacillus, and Alloprevotella	Intestinal inflammation	(Chen et al. 2021b)
Sprague–Dawley rats gut	250 ± 20 g	Male	Alternate injections of either METH (1 mg/kg, i.p.) for 14 d	Genus	↑: Ruminococcaceae, Bacillus, Cetobacterium, Fusobacteria, and Aeromonas	METH addiction	(Ning et al. 2017)
	60–90 d	Male	Injection of METH (2 mg/kg, i.p.) for 14 d	Phylum	↑: Actinobacteria ↑: Bacteroidetes	Depressive-like behavior	.(Forouzan et al. 2021)
				Genus	↑: Allobaculum, Bifidobacterium, and Lactobacillus
	220–250 g	Male	Self‐administration of intravenous METH (0.05 mg/kg) for 3 h/day over 15 d	Phylum	↑: Desulfobacterota, and Campilobacterota ↓: Proteobacteria	METH addiction	(He et al. 2025)
				Class	↑: Desulfovibrionia, and Campylobacteria ↓: Gammaproteobacteria
				Order	↑: Oscillospirales, Clostridia_UCG_014, Desulfovibrionales, and Campylobacterales ↓: Burkholderiales, Parvibaculales, Mycoplasmatales, Cellvibrionales, Enterobacterales, and Clostridia_vadinBB60_group
				Family	↑: Muribaculaceae, Prevotellaceae, Oscillospiraceae, Lactobacillaceae, Ruminococcaceae, Clostridia_UCG_014, Desulfovibrionaceae, Helicobacteraceae, and Eubacterium_coprostanoligenes_group ↓: Bacteroidaceae, Sutterellaceae, Parvibaculaceae, Mycoplasmataceae, Enterococcaceae, Spongiibacteraceae, Enterobacteriaceae, Comamonadaceae, and Clostridia_vadinBB60_group
				Genus	↑: Muribaculaceae, Lachnospiraceae_NK4A136_group, Prevotellaceae_Ga6A1_group, Prevotellaceae_NK3B31_group, Prevotellaceae_UCG_001, Lactobacillus, Clostridia_UCG_014, Roseburia, Clostridium_sensu_stricto_6, Ruminococcus, Helicobacter, Colidextribacter, and Eubacterium_coprostanoligenes_group ↓: Bacteroides, Lachnoclostridium, Parasutterella, Parvibaculum, Ruminococcus_gnavus_group, Mycoplasma, Enterococcus, Zhongshania, Aquabacterium, Escherichia_Shigella, Coprobacillus, Clostridioides, and Clostridia_vadinBB60_group
	180–200 g	Male	Alternate injections of either METH (2 mg/kg, i.p.) or saline for 10 d	Family	↑: Coriobacteriaceae, and Verrucomicrobiaceae	METH addiction	(Yang et al. 2021a)
				Genus	↑: Akkermansia, Allobaculum, and Olsenella ↓: Acetivibrio
	260–280 g	Male	Self-administration of METH 6 h per day for 9 d	Family	↑:Bacteroidales_S24_7_group and  Eubacteriaceae ↑:Dietziaceae, Brevibacteriaceae, Dermabacteraceae, Staphylococcaceae, and  Streptococcaceae	Gut microbiota dysbiosis and intestinal barrier damage	(Yu et al. 2023)
Human gut	Adults	Male&female	Sustained use	Order	↑: Thermoanaerobacterales	Sleep disturbance	(Deng et al. 2024a)
				Family	↑: Thermoanaerobacteraceae, and Clostridiaceae_1,
				Genus	↑: Clostridium_ sensu_stricto_1, Enterorhabdus, Gelria, Holdemanella, Oscillibacter, and Sutterella ↓: Clostridium_ sensu_stricto_1, Enterorhabdus, Gelria, Holdemanella, Oscillibacter, and Sutterella
	Adults	Male	METH withdrawal	Genus	↑: Collinsella, Odoribacter, and Megasphaera ↓: Faecalibacterium, Blautia, Dorea, and Streptococcus	Systemic inflammation	(Deng et al. 2021)
	Adults	Male&female	Sustained use	Genus	↑: Halomonas, Clostridium, Devosia, and Dorea	METH-induced paranoia, depression, Fatigue, drowsiness, and increased appetite	(He et al.2023a)
	Adults	Female	METH addicts	Genus	↑: Bacteroides, and Roseburia	Depression and anxiety	(Wang et al. 2023c)
	Adults	Male	METH users	Genus	↑: Fusobacterium, Granulicatella, and Anaerococcus ↓: Parabacteroides, Collinsella, Paraprevotella, and multiple Clostridiales organisms	Intestinal microbiota dysbiosis	(Fulcher et al. 2018)
	Adults	Male	METH users	Genus	↑: Finegoldia, Fusobacterium, Peptoniphilus, Porphyromonas, Streptobacillus, and Streptococcus ↓: Bacteroides, Faecalibacterium, and Succinivibrio	Depression	(Cook et al. 2019b)
	Adults	Male&female	METH use disorder	Phylum	↑: Firmicutes, Proteobacteria and  c Actinobacteria	METH addiction	(Liu et al. 2023a)
				Genus	↑: Lachnoclostridium, and Lachnospira ↓: Bifidobacterium
	Adults	Male	METH-dependent individuals	Genus	↓: Lactobacillus, Lactococcus lactis, Prevotellaceae, Ruminococcaceae, and Blautia	Impaired working memory and intestinal microbiota dysbiosis	(Zhu et al. 2023)
	Adults	Male&female	METH use disorder	Family	↑: Actinomycetaceae, Lachnospiraceae, Aeromonadaceae, Succinivibrionaceae, and Synergistaceae	Impulsivity	(Liu et al. 2024c)
				Genus	↑: Escherichia_Shigella, Lachnoclostridium, Sutterella, Alloprevotella, Tyzzerella_4, Faecalitalea, Eisenbergiella, Succinivibrio, Enterobacter, Actinomyces, Peptostreptococcus, and Citrobacter
	Adults	Male	METH use disorder	Family	↑: Rikenellaceae, an unidentified Clostridiales, Desulfovibrionaceae ↓: Tannerellaceae, Lactobacillaceae, Xanthomonadaceae, Sphingomonadaceae, and Peptococcaceae	Psychotic syndrome and cognitive impairment	(Yang et al. 2021c)
Human oral cavity	Adults	Male&female	METH users	Phylum	↑:Acidobacteria, Patescibacteria, Planctomycetes, and Synergistetes ↓: Proteobacteria, and Tenericutes	Poor oral health	(Zhang et al. 2023a)
				Species	↑: V. dispar ↓: N. subflava, H. parainfluenzae, F. periodonticum, and P. melaninogenica
	Adults	Female	METH users	Phylum	↑: Proteobacteria, and Bacteroidetes ↓: Firmicutes, Actinobacteria, and Fusobacteria	Salivary inflammation	(Deng et al. 2022)
				Genus	↑: Neisseria, Porphyromonas, Prevotella, Rothi, Fusobacterium, and Haemophilus ↓: Veillonella, Streptococcus, Leptotrichia, and Actinomyces
	Adults	Male	METH addicts	Class	↑: Negativicutes	METH addiction	(Yang et al. 2021d)
				Family	↑: Veillonellaceae, and Cryptosporangiaceae
				Genus	↑: Veillonella
	Adults	Male&female	METH addicts	Genus	↑: Granulicatella, Gemella, and Peptostreptococcus ↓: Campylobacter, Aggregatibacter, and Dialister	METH addiction	(Wang et al. 2024a)

[i] METH was administered in an escalating dose regimen (1.5 mg/kg, on days 1–2; 4.5 mg/kg on days 3–4; 7.5 mg/kg on days 5–6; once daily, i.p.); then, on days 7–8, four injections of 10.0 mg/kg (i.p.) were given at 2 h intervals

[ii] 0.5 mg/kg for 4 days, 1.0 mg/kg for 3 days, 2.0 mg/kg for 4 days, 4.0 mg/kg for 3 days, with a one-day interval between each meeting

METH: methamphetamine

Microbiota-gut-brain axis

Over the past few decades, microbiology has become increasingly linked to neuroscience (Agirman and Hsiao 2021). The gut mucosal barrier is of pivotal significance as a boundary that facilitates interactions between the host organism and its microbial communities. Once the gut mucosal barrier is disrupted, peptidoglycans, LPS, and other antigens present within the bacterial flora can pass through the compromised barrier and affect the inflammatory response of other organs by recognizing self- and non-self-antigens (Schneider et al. 2024). Emerging research findings have indicated that alterations in the composition of the gut microbiota have the potential to influence brain function and behavioral patterns (Diaz Heijtz et al. 2011; Huo et al. 2017; Wong et al. 2016). With the increased permeability of the BBB following METH use, endotoxin components can be systemically transported to the brain, triggering inflammation and exacerbating neuropsychiatric disorders (Ma et al. 2019). Therefore, the understanding of the microbiota-gut-brain axis is important to capture how gut microbiota contributes to the pathogenesis of neurotoxicity and addictive caused by METH (Fig. 1).

Fig. 1.

Microbiota-gut-brain axis crosstalk mechanisms. METH induces intestinal homeostasis disorder in multiple ways, including microbial composition, gut barrier permeability, and the gut microbiota derived‐functional metabolites (tryptophan metabolites, SCFA, LPS, and TMAO and inflammatory factors, etc.). Furthermore, the gut microbiota and its metabolites are involved in METH-induced neurotoxicity through multiple pathways, including inhibited neurogenesis and synaptic plasticity, neuroinflammation; mitochondrial damage, oxidative stress, neuroendocrine and HPA axis. SCFA: short chain fatty acids; LPS: lipopolysaccharide; TMAO trimethylamine N-oxide; and METH: methamphetamine

METH exposure affects the gut microbiota via the enteric nervous system, which contributes to its neurotoxic and addictive effects (Deng et al. 2024a; Ning et al. 2017; Wang et al. 2023b, 2021b; Yang et al. 2021a). In addition, the massive release of dopamine and norepinephrine induced by METH stimulates bacterial growth, and bacteria may also affect neural activity in stressed brain regions (Prakash et al. 2017). The alteration of gut microbiota also influences METH-induced changes in brain behavior and structure (Wang et al. 2021b; Yang et al. 2021a). The administration of antibiotics to mice with behavioral abnormalities induced by METH has been demonstrated to result in the improvement of these abnormalities (Lai et al. 2022a; Zhang et al. 2023b). Notably, recipient mice that received fecal transplants from the METH-treated group exhibited comparable alterations in brain structure and behavior, mirroring the phenotypes observed in the original METH treatment group (Yang et al. 2023). Furthermore, the fecal microbiota from mice treated with METH-induced colitis reproduced anxiety- and depression-like behaviors in the recipients (Zhang et al. 2023b, 2022b). Alterations in the gut microbiota are inextricably linked to the neurotoxic effects of METH and the development of dependence (Forouzan et al. 2021). Chronic METH can inhibit the subsequent activation of brain regions and cell phenotypes related to the hypothalamic–pituitary–adrenal (HPA) axis and oxidative stress (Jones et al. 2018). In addition, in specific regions (CA1, CA3, nucleus accumbens core, paraventricular hypothalamus), this reduction is gender—specific (Jacobskind et al. 2018). The gut microbiota's influence on HPA axis gene expression patterns and the resultant physiological responses is associated with neuropsychiatric disorders (Ge et al. 2021). In turn, the altered HPA axis activity partially changes the microbial community and composition (Vagnerova et al. 2019). Therefore, we have reason to believe that METH-induced gut microbiota dysregulation may also contribute to METH-induced neurotoxicity through the involvement of the HPA axis and oxidative stress pathways.

The gut microbiota has been shown to affect METH induced brain function through gut and immune interface (Prakash et al. 2017). Some gut microbiota such as E.coli (Hamed et al. 2023) or Clostridium difficile (Huang et al. 2019) can increase intestinal permeability and affect BBB permeability (Braniste et al. 2014), facilitating inflammatory mediators to pass the BBB (Rodriguez-Gomez et al. 2020; Yu et al. 2023). Upon the increase of intestinal permeability, pro-inflammatory cytokines (e.g., IL-6, TNF-α) traverse the BBB or travel via vagal afferent fibres to the central nervous system (CNS), where they further induce excessive activation of microglia (Zhou et al. 2025). Microglia, functioning as specialized surveillance units within the CNS, exhibit exquisite sensitivity to molecular fluctuations in their microenvironment (Kettenmann et al. 2011; Nimmerjahn et al. 2005). The disturbance of gut microbiota induced by METH triggers the conversion of microglia from M2 to M1 and subsequently activates the TLR4-NF-κB, NLRP3 inflammasome, Wnt/β-Catenin/GSK3β, proBDNF-p75NTR, and mature BDNF-TrkB signaling pathways, which leads to neuroinflammation, a decrease in hippocampal neurogenesis, and reduced expression of synaptic plasticity-related proteins, and ultimately worsens METH-induced spatial learning and memory deficits (Wu et al. 2023). Upon activation, microglia secrete various cytokines and chemokines, thereby attracting neighboring immune cells and mobilizing monocytes from the peripheral circulation into the brain (Liu et al. 2016). Moreover, microbial translocation across a leaky gut barrier triggers immune activation via pathways dependent on intestinal metabolites. For instance, when LPS, a component of the cell wall of Gram-negative bacteria, leaks from the intestinal tract, it can cause endotoxemia and systemic inflammation (Prajapati et al. 2023; Wang et al. 2022b). Erny et al. also demonstrated that gut microbiota-derived SCFAs can regulate microglia homeostasis (Erny et al. 2015). With the increased permeability of the BBB following METH use, endotoxin components can be systemically transported to the brain, triggering inflammation and exacerbating neuropsychiatric disorders (Ma et al. 2019). This finding provides novel insights into the process by which METH exacerbates neurotoxicity through the mechanisms of microbial–gut–immune interaction.

Gut microbiota metabolites have been identified as potential mediators in bidirectional gut-brain signaling. SCFAs may be the most studied gut microbial-derived metabolites. Microbial fermentation of certain host-indigestible dietary fibers is the primary source of SCFAs (Baxter et al. 2019), most of which are acetate, propionate, and butyrate. Recently, SCFAs have been shown to play a specific role in promoting intestinal barrier integrity which can enhance the mucosal barrier by stimulating mucus production and stimulate tight junction assembly to alleviate impairments in epithelial barrier integrity (Jung et al. 2015; Peng et al. 2009). As demonstrated by experimental studies, SCFAs play a role in maintaining homeostasis within the central nervous system. Evidence has been presented indicating that SCFAs can diffuse across the BBB and reach the brain, where they directly act on glial cells (Cao et al. 2025). Supplementing SCFAs can reverse the inhibition of hippocampal neurogenesis and alleviate neuroinflammation induced by microglial activation in METH-exposed mice (Chen et al. 2024). In addition, indole derivatives drive AhR activation to alleviate-induced METH microglial dystrophy and reduce neurogenesis in the hippocampus (Wang et al. 2025a).

Mitochondrial damage has long been considered to play a crucial role in METH-induced dopaminergic neurotoxicity. Studies have shown that energy metabolism in mitochondria is dysregulated after METH administration (Feier et al. 2012; Shin et al. 2018). Recent findings suggest that METH neurotoxicity is associated with the dysregulation of mitochondrial dynamics, encompassing biogenesis, mitophagy, and fusion/fission (Parameyong et al. 2013). Mounting data highlight the critical involvement of mitochondria in modulating BBB permeability and its related neural functions (Gu et al. 2021). Through increasing the permeability of the BBB or damaging the BBB, mitochondrial dysfunction in the peripheral system may exacerbate METH neurotoxicity (Lu et al. 2001). Dysfunctional mitochondria are hypothesized to generate nitric oxide (NO), leading to BBB disruption, the influx of extracellular substances, and the propagation of inflammation to microglia (Lu et al. 2001). Microbiota intervention has been proven to restore the mitochondrial-dependent hippocampal apoptosis pathway in an animal model of Alzheimer's disease (Bonfili et al. 2017). The microbiota and probiotics target the AMPK signaling pathway to regulate mitochondrial function and decrease tau phosphorylation in Alzheimer's disease (Bonfili et al. 2020). Microbiota-derived acetate and butyrate serve as essential substrates for neonatal lipid metabolism, ultimately being converted into acetyl-CoA (Zambell et al. 2003). SCFAs are known to directly activate AMPK, the central energy stress sensor, through an increase in the AMP/ATP ratio (Bonfili et al. 2017), thereby enhancing mitochondrial function. In addition, secondary bile acids are also involved in the host's energy production and reduce reactive oxygen species (ROS) by enhancing mitochondrial function in the peripheral and central nervous systems (Liu et al. 2020). Therefore, we have reason to believe that the gut microbiota and its metabolites may also affect mitochondrial function and be involved in METH-mediated neurotoxicity.

Microbiota-gut-liver axis

The concept of the microbiota-gut-liver axis encompasses the bidirectional relationship between the gut, microbiota, and the liver. This interaction is established by the portal vein, which serves as a conduit for the direct transport of products derived from the intestine to the liver. Additionally, the portal vein facilitates the liver feedback pathway, which is responsible for the secretion of bile and antibodies into the intestine (Albillos et al. 2020; Hsu and Schnabl 2023). The regulation of microbial populations is of paramount importance for maintaining the homeostatic balance of the gut-liver axis, and as part of this bidirectional communication network, the liver exerts a profound influence on the composition and activity of the gut microbiota (Albhaisi et al. 2020; Albillos et al. 2020; Milosevic et al. 2019). In addition to severe neurotoxicity, clinical evidence indicates that both chronic and acute METH exposure can result in liver damage and even liver failure (Eskandari et al. 2014; Kamijo et al. 2002; Willson 2019). The hepatotoxic consequences induced by METH are the result of complex mechanisms, including metabolic dysfunction, mitochondrial damage, an abnormal elevation of biogenic amines and hyperthermia, liver inflammation, apoptosis, and autophagy of liver cells (Eskandari et al. 2014; Kamijo et al. 2002; Li et al. 2020; Wang et al. 2017; Willson 2019). The intestinal microbiota and their metabolites exert regulatory effects on the gut-liver axis. An expanding body of evidence indicates a correlation between dysbiosis of the gut microbiota and the development of various liver diseases, including chronic hepatitis B, alcoholic liver disease (ALD), non-alcoholic fatty liver disease, liver cirrhosis, and hepatocellular carcinoma (Albhaisi et al. 2020; Dukic et al. 2023; Milosevic et al. 2019; Tilg et al. 2022; Wang et al. 2021a). For instance, a recent study revealed that the gut microbial metabolite TMAO disrupts mitochondrial protein homeostasis by activating heat shock protein 90β (Guo et al. 2025). This leads to mitochondrial dysfunction, characterized by MPTP opening, diminished MMP, and elevated ROS production, thereby worsening the progression of metabolic-associated fatty liver disease. Furthermore, accumulating evidence suggests that gut microbial communities are critically involved in the pathogenesis of substance abuse-related hepatic injury.

The administration of METH was found to markedly enhance the activation of inflammatory pathways within the liver, including the TLR4 pathway (Zhang et al. 2022c). The elevated serum LPS levels observed in mice treated with METH suggest an overproduction of LPS and dysbiosis of the gut microbiota (Yang et al. 2023). The administration of antibiotics has been demonstrated to alleviate the liver damage and gut microbiota dysbiosis induced by METH (Wang et al. 2022a). In an animal study, Zhang et al. found that supplementation with SCFAs ameliorated METH-induced hepatic injury (Zhang et al. 2024a). This finding suggests that gut microbiota dysbiosis could be a critical factor in the pathogenesis of METH-associated liver toxicity, thereby further suggesting the possibility that the microbiota-gut-liver axis may play a role in the METH damage process (Zhang et al. 2024a). The administration of METH has been demonstrated to induce several adverse effects, including cholestasis, dysfunction, inflammation in the liver, gut microbiota dysbiosis, and disruption of the homeostasis of bile acids (BAs) (Zhang et al. 2022c). Obeticholic acid (OCA), which acts as an antagonist of the farnesoid X receptor, has been observed to normalize the accumulation of METH-induced BAs in the serum and liver and to effectively protect against METH-induced liver dysfunction and inflammation (Zhang et al. 2022c). Prenatal exposure to METH has been demonstrated to result in liver damage in offspring, which may be attributed to alterations in the cecal microbiota and dysregulation of BAs homeostasis (Li et al. 2024). It is worthy of note that the administration of inulin to the fetus during gestation has been demonstrated to have the capacity to normalize the intestinal microbiota of the offspring and to alleviate hepatic toxicity associated with exposure to METH during gestation (Li et al. 2024). Collectively, these findings demonstrate the involvement of the gut microbiota in METH-induced hepatotoxicity via modulation of the gut-liver axis (Fig. 2). Nevertheless, future studies are warranted to precisely define the mechanistic role of this axis in the pathogenesis of METH-associated liver damage.

Fig. 2.

The connection between the liver and the intestine is bidirectional. Specifically, gut-derived microbial metabolites could directly influence the liver, in contrast, liver‐generated factors including primary bile acids could affect intestinal homeostasis after METH exposure

Microbiota-gut- heart axis

Available evidence confirms that METH intake is correlated with increased rates of hypertension, coronary artery disease, and sudden cardiac death (Jafari Giv 2017; Kevil et al. 2019; Marcinko et al. 2019; Schwarzbach et al. 2020; Stokes et al. 2022; Sun et al. 2019). Both retrospective and prospective cohort studies indicate that the prevalence of METH-related cardiomyopathy among individuals presenting with cardiomyopathy has been rising steadily over time, those who have used METH are at an almost fourfold increased risk of developing cardiomyopathy when compared to individuals without a history of METH exposure (Neeki et al. 2016; Tomita et al. 2013). Animal experiments have shown that the chronic administration of METH has been demonstrated to result in a reduction in cardiac contractile function in mice, an elevation in the expression of age-related biomarkers within cardiac cells, and the accelerated aging of these cells through the GATA4/NF-κB/SASP pathway (Zhao et al. 2023b). Prolonged METH exposure results in impaired myocardial contractility and ejection fraction, coupled with dysregulated expression of circadian rhythm-related genes and their downstream effectors in rats (Zhang et al. 2022a). METH has been proven to cause cardiomyopathy by elevating sigma non-opioid intracellular receptor 1 (Sigmar1) levels, thereby impairing mitochondrial dynamics and function (Abdullah et al. 2020). Abnormal circadian rhythms may offer novel avenues for investigating METH-related heart failure (Zhang et al. 2022a). The available evidence suggests that prenatal exposure to METH may induce alterations in cardiac gene transcription, increase vulnerability to ischaemic insult, and influence vascular functionality, thereby elevating the likelihood of developing cardiovascular disorders later in life (Belcher and Rorabaugh 2023; Chavva and Rorabaugh 2022; Dague et al. 2022; Rorabaugh et al. 2016). While cessation of METH use is the most effective intervention for reversing cardiomyopathy, drug therapy remains integral to comprehensive management (Osekowski et al. 2022). Vanillic acid (Shabani et al. 2023), Rhynchophylline (Zhou et al. 2020), cannabidiol (Nie et al. 2022), and exercise training (Dolezal et al. 2014; Shahrabadi et al. 2022) mitigate the effects of METH-induced cardiac injury to varying degrees. Nevertheless, there is currently no established therapeutic option for the management of METH-induced cardiac injury.

A substantial body of research has demonstrated the regulatory function of intestinal microbial communities in the development and progression of cardiovascular diseases (Tang et al. 2017; Zhang et al. 2021; Zhao et al. 2023a). Gut microbiota engages in dynamic crosstalk with the host organism via distinct molecular mechanisms, notably through trimethylamine and its hepatic oxidation product TMAO, microbiota-derived SCFAs, and the primary and secondary BAs (Tang et al. 2017). In addition to the aforementioned metabolic pathways, metabolic processes independent of these pathways may also have an impact on the pathogenesis of cardiovascular diseases (Fung and Tang 2023; Rahman et al. 2022; Zhang et al. 2024b; Zheng et al. 2024). For example, visceral congestion, edema of the intestinal wall, and disruption of the intestinal barrier integration are thought to trigger the migration of microorganisms into the body's circulation, facilitating the spread of bacterial by-products and exacerbating the inflammatory response (Qian et al. 2022; Tang et al. 2017; Zhang et al. 2021). After these by-products enter the human body, they will be recognized by pattern recognition receptors (PRR) expressed on immune cells and activate these receptors, thereby inducing the release of inflammatory factors and the maturation of dendritic cells, thus triggering an inflammatory response. For instance, LPS has been demonstrated to induce cardiomyocyte apoptosis while simultaneously increasing mitochondrial ROS production (Cheng and Huang 2021). Furthermore, these ROS have been demonstrated to contribute to the development of cardiomyocyte fibrosis and hypertrophy. In addition, mitochondria play a crucial role in cardiac physiology, including regulating cardiac metabolism, function, and remodeling, while the accumulation of fragmented and damaged mitochondria is a hallmark of heart disease. In addition, the interaction between the microbiome and mitochondria is also involved in a variety of heart diseases. For example, Accumulating evidence indicates that elevated TMAO levels promote the development of non-ischemic heart failure by triggering myocardial hypertrophy and fibrosis via the TGF-β/Smad signaling pathway, while also compromising mitochondrial energy production, altering DNA methylation patterns, and disrupting intracellular calcium transport (Khalil et al. 2017). Aberrant BA levels worsen ischemic and non-ischemic heart failure by compromising contractility, inducing apoptosis via mitochondrial permeability transition pore opening, and enhancing cholesterol accumulation (Beach et al. 2020). The microbiota-gut-heart axis is emerging as a major pathway linking gut microbiota and cardiovascular disease.

Accumulating evidence positions the gut microbiota as a central player in the development of cardiotoxicity following METH exposure. Liu et al. demonstrated that an increase in the diversity and abundance of the gut microbiota was associated with cardiotoxicity after exposure to METH (Liu et al. 2023b). This was accompanied by a marked elevation in Lactobacillus and Bifidobacterium, and a significant reduction in Bacteroides, norank_f_Muribaculaceae, and Alistipes. Crucially, antibiotic-mediated depletion of gut microbiota attenuated cardiac damage, whereas fecal microbiota transplantation from METH-exposed mice reproduced cardiotoxic effects in healthy recipients (Liu et al. 2023b). These results demonstrate that gut microbiota play a causal role in METH-induced cardiotoxicity, providing strong evidence for the microbiota-gut-heart axis (Fig. 3). Nevertheless, the exact mechanistic pathways linking gut microbiota to cardiac dysfunction remain to be fully elucidated.

Fig. 3.

Microbiota-gut-heart axis crosstalk mechanisms. Gut microbiome-derived metabolites (like LPS) aggravate heart injury by promoting vascular endothelial cell death and cardiomyocyte apoptosis through the induction of oxidative stress, mitochondrial damage, and inflammatory factors

Microbiota-gut-reproduction axis

The reproductive organs of male and female

A substantial body of research indicates that METH abuse can inflict varying degrees of toxic damage to the reproductive system. METH has been used as an aphrodisiac (Skårner and Svensson 2017). The repeated administration of METH, particularly at elevated doses, has been demonstrated to result in a reduction in the proliferation of rodent germ cells, the induction of apoptosis, and an alteration in the proliferation/apoptosis ratio within the testis (Alavi et al. 2008). In addition to its impact on spermatogenesis, METH has been demonstrated to exert direct effects on sperm quality, including sperm viability, sperm morphology, and sperm concentration (Nudmamud-Thanoi et al. 2016). The family of sperm-specific cation channels plays an essential role in sperm motility and can act as regulators of sperm motility (Ren et al. 2001). In an animal experiment, Allaeian et al. found that METH reduced the expression levels of the CatSper and Mvh, which in turn reduced sperm motility by affecting cation channels (Allaeian Jahromi et al. 2022). In a cross-sectional study of female METH users, researchers found that long-term METH use significantly altered participants' menstrual cycles, with 33.6% experiencing abnormal uterine bleeding during METH use (Shen et al. 2014). Despite periods of abstinence, hormonal imbalances were still evident in 73.3% of participants. Wang et al. have determined that long-term METH use has a detrimental effect on ovarian reserve in adolescent mice (Wang et al. 2016). This is characterized by the activation of apoptotic pathways in ovarian tissue, a reduction in the number of primordial and growing follicles, an increase in the number of atretic follicles, and a disruption in sex hormone secretion. This finding suggests a potential impact of METH abuse on female reproductive lifespan.

The gut microbiota has been demonstrated to exert a significant influence on reproductive function (Wang et al. 2024c; Wang and Xie 2022; Zhu et al. 2022). This is evidenced in that it can cause testicular and epididymal inflammation, reduce spermatogenesis, and lead to erectile dysfunction through translocation-induced immune activation, influencing the release and metabolism of sex hormones, and affecting the blood testis barrier (Wang and Xie 2022). Recently, Liu et al. found that reproductive damage caused by METH could be transferred from METH-exposed mice to healthy mice using the method of transplantation of fecal microbiota (Liu et al. 2024b). These findings suggest a potential association between METH-induced reproductive toxicity and the gut microbiota, identifying the latter as a critical mediator in the exacerbation of such toxicity (Fig. 4).

Fig. 4.

Microbiota-gut-reproduction axis crosstalk mechanisms. Following METH exposure, gut microbiome-derived metabolites (like LPS) aggravate testis and ovary injury by reducing reproductive lifespan through the induction of inflammatory responses and disorders in sperm or egg development. In the context of maternal METH exposure, alterations in the maternal gut microbiota regulates offspring's multi-organ toxicity by influencing gut microbial colonization

Pregnancy and offspring

As research progresses, METH has the potential to traverse the placental barrier, exerting a persistent influence on the developing fetus (Li et al. 2021). Prenatal exposure to METH has been linked to fetal growth restriction and low birth weight in newborns (Sankaran et al. 2022). The results of animal studies indicate that maternal use of METH is associated with a reduction in uterine and umbilical cord blood flow (Chavva and Rorabaugh 2022). A substantial body of evidence indicates that the maternal microbiota during pregnancy can significantly impact the developmental trajectory of the offspring (Calatayud et al. 2019; Vuillermin et al. 2017). Exposure to METH during pregnancy can disrupt the offspring's gut microbiota, serum metabolome, and BA homeostasis, and maternal inulin supplementation can reverse the disruption of the gut microbiota and serum metabolome in the offspring induced by METH (Li et al. 2024; Li et al. 2025a). In addition, patrilineal METH exposure in both first-generation (F1) and second-generation (F2) male mice induced depression-like behaviors. The reduction of gut microbiota caused by antibiotic treatment restored the depressive-like behavior of F1 and F2 male mice to normal levels (Zhang et al. 2025). Nevertheless, the precise mechanisms by which the gut microbiota mediate the effects of METH on reproductive toxicity remain uncertain and further research is needed to gain a deeper understanding of the precise pathways by which the gut microbiota contribute to this process.

Roles and mechanisms of gut and oral microbiota in human METH abusers

Roles and mechanisms of gut microbiota in human METH abusers

A substantial body of evidence from population-based studies has demonstrated that the abuse of METH can induce alterations in the structure of the gut and oral microbiota in the human body (Table 1). The composition of the gut microbiota in METH users has also changed, including a decrease in the number of Deltaproteobacteria and Bacteroidaceae, as well as an increase in the abundance of Sphingomonadales, Xanthomonadales, Romboutsia, and Lachnospiraceae (Yang et al. 2021c). In addition, the changes of some bacteria can serve as biomarkers for the duration of METH abuse, symptoms, and systemic inflammation, indicating the characteristics of METH abusers. For instance, alterations in Enterobacteriaceae, Ruminococcaceae, Bacteroides, and Faecalibacterium are linked to METH-induced psychiatric syndromes and cognitive impairment. Furthermore, Collinsella and Coriobacteriaceae are positively associated with the total duration of METH use, while Lactobacillales correlate positively with the length of abstinence (Deng et al. 2021). Additionally, the class Bacilli and its sub-taxa are positively correlated with the anti-inflammatory cytokine IL-10, whereas Actinobacteria/Dorea and Blautia show correlations with IL-6 and IL-2, respectively (Deng et al. 2021). Impulsivity and dysbiosis have been found in METH abusers, and the increased impulsivity and the disruption of the microbiota tend to recover after long-term abstinence from METH, and the impact of METH abuse on impulsivity is mediated by the microbiota (Liu et al. 2024c). Chronic METH administration not only induces hyperactivity but also alters the rhythms of feeding, drinking, body weight, core body temperature, and plasma/urine corticosterone, leading to changes in the rest-activity cycle in animal models (Morimasa et al. 1987). Similarly, in human subjects, both METH abuse and withdrawal lead to neuroendocrine disturbances, manifesting as circadian rhythm disruptions such as sleep disorders, and are closely associated with gut microbiota dysbiosis. For example, changes in the genus Sutterella may be associated with daytime dysfunction, suggesting that the genus Sutterella may be a biomarker for poor sleep quality in METH users (Deng et al. 2024a). The above studies indicate that a correlation has been identified between microbial imbalance and damage to the nervous system caused by METH.

Roles and mechanisms of oral microbiota in human METH abusers

In addition to gut microbiota, METH use also causes oral microbial dysbiosis (Table 1). For example, Zhang et al. reported that several specific phyla of the oral microbiota, such as the enrichment of Acidobacteria and the depletion of Proteobacteria and Tenericutes, can be consistently altered by heroin and METH addiction (Zhang et al. 2023a). Wang et al. found the oral microbiome of individuals who use METH has been shown to undergo significant alterations, characterized by an enrichment of Peptostreptococci and Gemella alongside a concurrent decrease in Campylobacter and Bacteroides, which was closely associated with increased tryptophan metabolism, lysine biosynthesis, porphyrin metabolism, glutathione metabolism, and a significant decrease in pentose phosphate metabolic pathways (Wang et al. 2024a). These key microbial taxa may contribute to the toxicity and addictive mechanisms of METH through the modulation of the aforementioned metabolic pathways. Emerging evidence suggests that oral microbiota dysbiosis can contribute to the development of oral diseases, including periodontitis (Wang et al. 2025c). Therefore, METH can induce oral microbiota dysbiosis, which may subsequently promote the progression of oral diseases. Compared to untreated healthy individuals, METH users exhibit a significant increase in the abundance of oral disease related bacterial communities (Yang et al. 2021d). Even after short-term abstinence from METH use and with improved oral hygiene habits, the composition of the oral microbiota in METH users remains unchanged. Moreover, there is a strong association between changes in plaque microbiota and salivary inflammation in METH users (Deng et al. 2022). Therefore, we have reason to believe that the various oral diseases caused by METH may be mediated by alterations in the structure and function of the oral microbiota.

Oral microbial dysbiosis has been demonstrated to result in the development of oral diseases, including periodontitis (Wang et al. 2025c). Moreover, it has been hypothesized that this condition may also influence the onset and progression of diseases in other organs through underlying mechanisms such as oxidative stress and immune inflammatory responses (Wang et al. 2025c). Oral bacteria are primary determinants of dental caries and periodontal disease states. The dynamic oral microbiome engages in bidirectional communication with systemic organs, cooperating with the host to reflect immunological and metabolic information (Peng et al. 2022). Oral microorganisms cause an inflammatory response through oral infections or cause an inflammatory response by ectopically colonizing other organs or tissues of the human body (such as tumors, intestines, heart, blood, brain, joints, placenta), affecting the process of systemic diseases (Baker et al. 2024; Hou et al. 2022). For example, a study indicates that Porphyromonas gingivalis, a pathogen associated with periodontitis, can be recognized by Toll-like receptor-2, promoting the release of inflammatory cytokines and other downstream factors, thereby accelerating the development of myocardial fibrosis in animal models (Kaneko et al. 2017). DNA of oral anaerobes such as Prevotella and Veillonella has been detected in the lungs of healthy subjects (Charlson et al. 2011; Einarsson et al. 2016). Micro—infections of oral and upper respiratory tract bacteria can trigger TH17 immune activation in the mucosal layer of the lower respiratory tract. TH17 inflammation may interact with environmental factors, participate in the pathogenesis of inflammatory lung diseases, alter the respiratory system's response to microorganisms, and thus may have long—term effects on respiratory function (Segal et al. 2016). Therefore, METH use may also induce oral toxic damage, particularly leading to various oral diseases, due to its disruption of the oral microbiota. However, current research on METH exposure and the oral microbiota has primarily focused on the changes in microbial composition following exposure. Few studies have examined the underlying mechanisms or the direct associations between the oral microbiota and oral damage—or even damage to other organs—caused by METH exposure. It is evident that further research is required to elucidate the precise mechanisms involved.

Commonalities and differences of gut and oral microbiota

METH exposure drives distinct yet overlapping dysbiosis patterns in the oral and gut microbiomes, characterized by the depletion of beneficial taxa and the expansion of pro-inflammatory bacteria (Table 2). Oral bacterial changes involve Proteobacteria enrichment and Actinobacteria loss (Deng et al. 2022), whereas gut shifts across human and animal models primarily show increased Firmicutes and decreased Bacteroidetes at the phylum level (Li et al. 2024; Liu et al. 2023a). Functionally, while the oral microbiota shows enrichment in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways such as tryptophan metabolism and lysine biosynthesis, research on associated oral microbiota-derived metabolites remains limited (Wang et al. 2024b). In contrast, animal gut models reveal a profound dysregulation of derived metabolites, where gut microbiota-derived metabolites changes affect systemic damage; this includes depleted SCFAs, elevated TMAO and LPS, and altered BA pools marked by increased T-β-MCA and decreased TCA or GCA (Liang et al. 2023b; Wang et al. 2025a, 2025b, 2023b; Zhang et al. 2023b, 2022c). Notably, the tryptophan metabolic pathway was enriched in METH-induced gut and oral microbiota dysbiosis. METH also triggered local oral pathology—such as pH shifts and hyposalivation in human models (Deng et al. 2022; Zhang et al. 2023a)—and increased intestinal permeability via the loss of tight junction proteins in animal models (Chen et al. 2024, 2021a; Shen et al. 2020b; Wang et al. 2022d). In the oral cavity, the overgrowth of genus Neisseria is closely linked to local inflammation in METH abusers (Deng et al. 2022). Simultaneously, gut microbiota dysbiosis facilitates the activation of the gut-brain, gut-liver, and gut-testis axes. For instance, a positive correlation was found between the relative abundance of the genus Sutterella and sleep disturbances (Deng et al. 2024b). Furthermore, the proliferation of Roseburia is associated with liver dysfunction (Zhang et al. 2022c), while a significant correlation between genera such as Lachnospiraceae_NK4A136_group, norank_f_Muribaculaceae, and reproductive-related parameters in the testis (Liu et al. 2024b). METH induces alterations in the oral microbiota; these changes contribute to METH-induced oral tissue pathology, yet the impact of such microbial shifts on organs or tissues beyond the oral cavity remains unaddressed in METH abusers (Deng et al. 2022). Overall, dysbiosis of the oral and gut microbiota promotes METH-induced dysfunction in these niches by disrupting microbial signaling and breaking down essential biological barriers.

Table 2.

Commonalities and differences of gut and oral microbiota

Comparison Dimension		Differences			Commonalities
		Oral Microbiota	Gut Microbiota
		Human	Human	Animals
Alterations in microbial abundance	Phylum	↑: Acidobacteria, Patescibacteria, Planctomycetes, Synergistetes, Proteobacteria (Deng et al. 2022b; Zhang et al. 2023a) ↓: Actinobacteria (Deng et al. 2022)	↑: Firmicutes (Liu et al. 2023a)	↑: Firmicutes [(Li et al. 2024; Wang et al. 2022c, 2025a, 2023b ; Wu et al. 2023), ↓: Bacteroidetes (Li et al. 2024)	Microbiota dysbiosis marked by the depletion of beneficial bacteria and enrichment of pro-inflammatory bacteria
	Class	↑: Negativicutes (Yang et al. 2021d)	None	↑: Desulfovibrionia, Campylobacteria (He et al. 2024)
	Family	↑: Veillonellaceae, Cryptosporangiaceae (Yang et al. 2021d)	↑: Rikenellaceae, Ruminococcaceae, Enterobacteriaceae, Lachnospiracea (Liu et al. 2024a; Yang et al. 2021b; Zhu et al. 2023) ↓: Prevotellaceae (Zhu et al. 2023)	↑: Rikenellaceae, Ruminococcaceae, Enterobacteriaceae, Lachnospiracea (Chen et al. 2024; He et al. 2024; Wang et al. 2022b; Wu et al. 2023; Yang et al. 2022) ↓: Prevotellaceae (Chen et al. 2024; Wang et al. 2022b)
	Genus	↑: Neisseria, Porphyromonas, Prevotella, Fusobacterium, Haemophilus, Peptostreptococcus (Deng et al. 2022; Wang et al. 2024b) ↓: Veillonella, Streptococcus, Leptotrichia, Actinomyces (Deng et al. 2022)	↑:Rikenella, Mucispirillum, norank_f__Desulfovibrionaceae, Mycoplasma, Turicibacter, Dorea, Enterorhabdus, Escherichia-Shigella, Bacteroides, Alistipes, Sutterella, Fusobacterium, Lachnoclostridium (Cook et al. 2019a; Liu et al. 2024a, 2023b) ↓: norank_f__Muribaculaceae, Alloprevotella, Akkermansia, Paraprevotella, Parabacteroides, Bacteroides, Lactobacillus, Faecalibacterium, Blautia (Cook et al. 2019a; Deng et al. 2021; Fulcher et al. 2018; Zhu et al. 2023)	↑: Rikenella, Mucispirillum, norank_f__Desulfovibrionaceae, Mycoplasma, Turicibacter, Dorea, Enterorhabdus, Escherichia-Shigella, Bacteroides, Alistipes, Sutterella, Fusobacterium, Lachnoclostridium (Chen et al. 2021a; Deng et al. 2024b; He et al. 2023b; He et al. 2024; Lai et al. 2022b; Li et al. 2025b; Liang et al. 2023b; Loor et al. 2020; Yang et al. 2023; Zhang et al. 2023b; Zhang et al. 2022c; Zhuang et al. 2024b) ↓: norank_f__Muribaculaceae, Alloprevotella, Akkermansia, Paraprevotella, Parabacteroides, Bacteroides, Lactobacillus, Faecalibacterium, Blautia (Chen et al. 2021a; He et al. 2024; Lai et al. 2022b; Li et al. 2025b; Liu et al. 2023b; Lu et al. 2023b; Wang et al. 2022c; Wang et al. 2023b; Yang et al. 2023; Zhang et al. 2022c)
Microbial functional analysis and changes in microbiota-derived metabolites	tryptophan metabolism, lysine biosynthesis, purine metabolism, and steroid biosynthesis (Deng et al. 2022b; Wang et al. 2024b)		purine metabolism and fatty acid metabolism (Deng et al. 2021)	phenylalanine, tyrosine, and tryptophan biosynthesis and the tryptophan metabolism; gut microbiota-derived metabolites (e.g., ↓: SCFAs and Tryptophan metabolites, ↑: TMAO, LPS; Bile Acids (e.g., ↑: T-β-MCA, TCDCA and TUDCA ↓: GCA and TCA)) (Liang et al. 2023b; Wang et al. 2025a, 2025b, 2023b; Zhang et al. 2023d, 2022c)	METH-induced functional alterations in the gut microbiota involve the tryptophan metabolic pathway
Effects on the intestines and oral cavity	Deterioration of the oral microenvironment, characterized by pH shifts, hyposalivation, and shifted inflammatory profiles (Deng et al. 2022; Zhang et al. 2023a)		None	Disruption of gut integrity and function including loss of tight junction proteins and increased mucosal permeability (Chen et al. 2024, 2021a; Shen et al. 2020b; Wang et al. 2022d)	METH-induced structural and functional damage in intestinal and oral tissues
Systemic Crosstalk & Pathological Significance	None		Symptoms: sleep disturbance, craving, mental disorders and cognitive impairment) (Deng et al. 2024a; He et al. 2023b; Wang et al. 2023c; Yang et al. 2021e; Zhu et al. 2023)	Symptoms: craving, mental disorders, depression and anxiety (Forouzan et al. 2021; Wang et al. 2025a, 2021b)	None
			Tissue injury: None	Tissue injury: Impairment of structure and sunction in the brain, liver, heart, and testis (Liu et al. 2024b; Wang et al. 2025b; Yu et al. 2023; Zhang et al. 2022c)

Therapeutic implications

The treatment of substance use disorders represents a significant global concern. However, there exists a paucity of specific pharmacological interventions for the management of METH use disorder and its associated neuropsychiatric complications. The correlation that has been identified between the gut microbiota and METH abuse suggests the possibility that the gut microbiota could be a suitable therapeutic for the treatment of METH use disorder (Fig. 5).

Fig. 5.

Intervention strategies based on the microbiota. There are five main ways to intervene METH toxicity by gut microbiota, including probiotics, prebiotics, microbial metabolites, exercise, microbiota transplantation and medicine. Probiotics like Lactobacillus Acidophilus alleviate METH abuse by producing beneficial metabolites. Prebiotics like inulin alleviate METH induced liver injury in offspring. Microbial metabolites like SCFAs, and indole metabolites alleviate METH induced neurotoxicity. Medicine therapy, represented by natural drugs derived from Chinese herbal medicine and antibiotics, mainly produces renoprotective activity by anti‐inflammatory and anti‐oxidative mechanisms

Probiotics and prebiotics

Probiotics offer an economically sound alternative for enhancing human health and treating multiple chronic diseases by modulating host immunity, protecting against physiological stress, suppressing pathogens, regulating the microbiome, and bolstering the gut epithelium's barrier function (Suez et al. 2019). In recent years, probiotics have emerged as a new focus on treating neuropsychiatric disorders in human and animal models (Akkasheh et al. 2016; Li et al. 2018; Miyaoka et al. 2018).A clinical trial demonstrated that oral intake of probiotics may have beneficial consequences on mood and psychological distress (Messaoudi et al. 2011). L. helveticus R0052 and B. longum R0175, when administered together, exhibit anti-anxiety effects in rats and confer psychological benefits in healthy humans (Messaoudi et al. 2011). Multiple studies have demonstrated the involvement of the gut microbiota in drug addiction, and probiotics may be a promising therapeutic candidate involved in the treatment of drug addiction, including alcohol, cocaine, and METH (Luo et al. 2023; Qin et al. 2021). As previously stated, METH use is associated with a reduction in probiotics and an increase in pathogenic bacteria, accompanied by the corresponding symptoms (Liu et al. 2024c). Research shows probiotic (like Lactobacillus Acidophilus) use can improve sleep quality, appetite, and body mass index in long-term METH users (Badrfam et al. 2024). In consideration of the established correlation between gut microbiota and METH toxicity, we propose that probiotics may represent a promising avenue for the development of METH induced multi-organ toxicity treatments that target the gut microbiota. However, pre-clinical human data on the treatment of METH with probiotics are quite scarce. There is only one population cohort study (Badrfam et al. 2024), and it is recommended that more specific clinical trials with larger sample sizes and long-term case follow-ups be conducted in the future.

Numerous scientific reports have confirmed that probiotics are crucial for maintaining the balance of the human gut microbiota and have a positive impact on the host's health. Prebiotics can serve as alternatives to probiotics or provide additional support for them. For example, inulin has also been reported to be used in the treatment of liver injury in offspring induced by METH (Li et al. 2024). Enhanced 'probiotic biotherapeutic formulations' containing specific microbial strains and synergistic prebiotics have proven more effective than single components in providing protection and stimulation, potentially boosting probiotic effects in the small intestine and colon (Markowiak and Slizewska 2017). In the future, we still need to further explore the research on the combination of probiotics and prebiotics, synbiotics, as well as the specific mechanisms of their action in treating METH addiction and multi—organ toxic injury.

Modulation of gut microbiota community

Numerous studies have demonstrated that administering drugs to modulate the gut microbiota can mitigate the toxic effects of METH or METH addiction. Antibiotics, the most frequently employed pharmaceuticals to regulate the microbiota, are defined as natural or synthetic organic chemicals that inhibit or kill pathogenic bacteria, or any antimicrobial substance (Mohr 2016). In a behavioral assessment experiment, Wang et al. found that depletion of gut microbiota with antibiotics inhibited the formation of METH addiction, and fecal microbiota transplantation reversed this inhibition (Wang et al. 2023a). Meanwhile, Yu et al. also reported that microbiota depletion via antibiotic treatment prevented the incubation of METH craving which significantly decreased METH craving after prolonged withdrawal (Yu et al. 2023). In addition to alleviating the addictive behaviors associated with METH use, antibiotics can also mitigate the adverse effects of METH on muti-organ by regulating the composition of gut microbiota. A behavioral study further revealed that compared to the control group, germ-free mice and antibiotic-treated mice failed to develop anxiety-like behaviors during METH withdrawal (Lu et al. 2023a), indicating that antibiotics could potentially mitigate anxiety associated with METH withdrawal. Liu et al. demonstrated that antibiotic-mediated gut microbial restructuring attenuated METH-induced cardiotoxicity, whereas gut microbiota transfer from METH-exposed mice recapitulated cardiotoxic phenotypes in healthy recipients (Liu et al. 2023b). Besides antibiotics, other drugs can exert a modulatory effect on METH-addictive behavior or METH-induced toxic damage by modulating the gut microbiota. Lycium barbarum polysaccharide was found to improve METH-induced gut microbiota dysbiosis by increasing some beneficial genus abundances, such as Allobaculum, Gordonibacter, and Ileibacterium, and further alleviate METH-induced conditioned place preference and hyperactivity (Zhuang et al. 2024a). Gegen Qinlian Decoction alleviates anxiety-like behavior and improves the intestinal microenvironment in METH withdrawal mice by targeting Akkermansia metabolites (Lu et al. 2023a). Yang et al. found that METH significantly altered the composition and structure of gut microbiota, as well as the relative abundance of several bacterial metabolites, and that the addition of metformin remodeled these alterations and ameliorated METH-induced anxiety and depression-like behavior in mice (Yang et al. 2022). Hydrogen intervention, including ingestion and inhalation, improved the gut microbiota profile of METH abusers and significantly alleviated mental disorders caused by METH abuse (Wang et al. 2023c). In addition, Yang et al., have reported that OCA administration attenuated METH-induced gastrointestinal dysregulation via microbiome restructuring and intestinal barrier reinforcement, highlighting OCA as a prophylactic agent against METH-induced anxiety (Yang et al. 2023). In addition, moderate-intensity aerobic exercise may regulate changes in gut microbiota composition and amino acid and SCFA levels induced by METH administration in the animal (Liang et al. 2023a) and human (Zhu et al. 2023) studies. The above evidence suggests that the use of drugs to remodel the microbiota community can ameliorate METH addiction and METH-induced toxic damage, further demonstrating the important role that microbes play in METH addiction and METH-induced toxic damage.

Microbial metabolites

METH use leads to gut microbial disruption along with gut microbial metabolite disruption, and several studies have shown that supplementation with microbial metabolites can ameliorate METH-induced symptoms and behaviors. For instance, Lai et al. showed that supplementation with SCFAs may ameliorate METH-induced changes in gut microbiota, behavioral abnormalities, and inflammatory responses (Lai et al. 2022a). In an experiment, Zhang et al. similarly found that supplementation of SCFAs in a Sigma-1 receptor-dependent manner optimized METH induced microbial dysbiosis, improved colitis, and suppressed anxiety and depressive-like behaviors (Zhang et al. 2023b). In addition, microbiota-derived inosine has also been reported to restore METH-induced anxiety and depression-like behavior in mice (Yang et al. 2022). Furthermore, UHPLC-MS/MS profiling demonstrated that the serum levels of tryptophan-derived indole derivatives were significantly diminished in both human addicts and mouse models experiencing withdrawal (Wang et al. 2025a). Mice fed a high-tryptophan diet exhibited significantly reduced METH-associated depressive and anxiety-like symptoms. Furthermore, evidence indicates that the administration of tryptophan metabolic pathway such as indole-3-propionic acid (IPA), indole-3-acetic acid (IAA), and indole can markedly ameliorate the abnormal behaviors induced by METH (Wang et al. 2025a). The evidence presented above indicates that the use of microbiota-derived metabolites has the potential to be a treatment for METH-induced toxic damage or METH addiction. However, further research is required to explore the therapeutic applications of microbiota-derived metabolites in the future. Postbiotics are defined as preparations of inanimate microorganisms and their components that can bring health benefits to the host (Scott et al. 2022). In addition to SCFAs, the therapeutic mechanism of other components of postbiotics (such as exopolysaccharides, vitamins, acids, bacteriocins, enzymes, and peptides) against METH—induced toxic damage remains to be further studied. Mitochondria serve as pivotal organelles governing cellular energy metabolism, calcium homeostasis, and oxidative stress responses, thereby playing a critical role in growth, development, and the pathogenesis of various diseases (Qiao et al. 2024; Srikantha and Mohajeri 2019). A complex interplay between the gut microbiota and mitochondria has been identified, involving microbial abundance and metabolites that modulate mitochondrial activity (Gupta et al. 2026; Qiao et al. 2024). Targeting mitochondria through diet, prebiotics, probiotics, or microbial metabolites represents a promising therapeutic strategy to maintain health by optimizing mitochondrial fitness (Qiao et al. 2024).

Conclusion

This review elucidates a significant association between METH exposure and microbiota from the gut and oral cavity. Specifically, there is a notable reduction in the abundance of beneficial bacteria and an increase in theabundance of pathogenic bacteria induced by METH. Conversely, imbalances in microbiota may impact multi-organ functions via the microbiota-gut-brain, microbiota-gut-liver, microbiota-gut-heart, and microbiota-gut-reproduction axes, respectively, resulting in functional disturbances that may ultimately affect the development of METH addiction and METH-induced multi-organ toxicity. Furthermore, the immune system, as well as mitochondria, also plays a crucial role in the gut microbiota-mediated multi-organ toxicity induced by METH. Nevertheless, the majority of current research is still confined to the final outcomes of METH's impact on the gut microbiota and the direct manifestations of the effects of gut microbiota on METH damage. Consequently, further in-depth studies are required to elucidate the specific mechanisms by which microbes affect the different organs damaged by METH. In the future, microbiota may become a therapeutic target for METH abuse-related damage. As demonstrated by extant research, probiotics, prebiotics, microbiota modulation, and microbial metabolites are three pivotal therapeutic strategies that target the microbiota. These approaches have demonstrated varying degrees of efficacy in mitigating METH addiction or METH-induced damage across different animal models, suggesting their potential as interventions for METH addiction or METH-induced multi-organ toxicity. However, the majority of these studies are laboratory-based, and there is a significant discrepancy between laboratory studies and their subsequent clinical translation. To achieve clinical translation, researchers must first overcome this barrier. Consequently, while promising, the therapeutic targeting of the microbiota for METH-related multi-organ toxicity requires significant further research to bridge the gap between preclinical findings and clinical application.

Author Contribution

**Jiebin Rong**: Software, Resources, Writing – original draft, Investigation, and Data curation. **Jingshen Zhuang**: Methodology, Investigation, Data curation, and Formal analysis, Software. **Jialong Xu**: Methodology and Investigation. **Xia Yue**: Conceptualization, Data curation, Methodology, Supervision, and Writing – review & editing. **Xuebing Chen**: Conceptualization, Data curation, Funding acquisition, Formal analysis, Methodology, Supervision, Writing – original draft, and Writing – review & editing.

Funding

This work was supported by the National Natural Science Foundation of China (No. 82271536), the Basic and Applied Basic Research Foundation of Guangdong Province (No. 2021A1515110414), the Science and Technology Program of Guangzhou (No. 2025A04J4347), Youth S&T Talent Support Programme of Guangdong Provincial Association for Science and Technology (GDSTA) (No. SKXRC2025170), and Young Science and Technology Talent Support Program of Guangdong Precision Medicine Application Association (No. YSTTGDPMAA202502).

Data availability

No data was used for the research described in the article.

Declarations

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Conflict of interests

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The authors declare no competing interests.