Table 1.

Changes and characteristics of the gut microbiota in patients with three common CVDs.

Cardiovascular diseases	Patient population	Main findings/Outcomes	Mechanism	References
Atherosclerosis	70 with CAD, and 98 Ctrls	The relative abundance of Firmicutes, Bacteroidetes decreased, while Proteobacteria and Actinobacteria increased in the CAD group, Escherichia-Shigella, Lactobacillus, and Enterococcus were found to be significantly enriched in the CAD group.	Inflammation caused by disturbances in the gut microbiota accelerate the progression of coronary heart disease.	Zhu et al. (2018)
	39 CAD patients，and 50 healthy volunteers	The Lactobacillales was increased, whereas the phylum Bacteroidetes (the genera Bacteroides, Prevotella) was decreased in the CAD group.	Bacteroides fragilis can promote regulatory T-cell function, regulating adaptive immune.	Emoto et al. (2016)
	Of the 108 MZ twins, 14 pairs discordant for carotid intima-media thickness (IMT) were selected to undergo a stool sample analysis	The group with high IMT values had low microbiota diversity, Firmicutes/Bacteroidetes ratio was greater; the Firmicutes had higher abundance, whereas that of Prevotellaceae was lower. Normal carotid IMT values were associated with a substantially higher fraction of Prevotellaceae.	The carotid-femoral pulse wave velocity (PWV) was negatively correlated with gut microbiome alpha diversity. The specific mechanism awaits further study.	Szabo et al. (2021)
	41 controls, 56 subjects with pHTN and 99 with primary HTN	The microbiome characteristic in pre-hypertension group was quite similar to that in hypertension, genera such as Prevotella and Klebsiella are overepresented in individuals with pHTN or HTN, a reduction of Faecalibacterium, Oscillibacter, Roseburia, Bifidobacterium, Coprococcus and Butyrivibrio.	Prevotella may trigger the inflammatory response; over production of LPS by gut microbiota seems to be directly linked to HTN development.	Li et al. (2017)
Hypertension	4,672 subjects (mean age 49.8 ± 11.7 years, 52% women) from six different ethnic groups participating in the HELIUS study	The abundance of Roseburia spp., Clostridium sensu stricto spp., Roseburia hominis, Romboutsia spp., Streptococcus spp., and Ruminococcaceae NK4A214 spp. was negatively associated with both SBP and DBP.	SCFA-producing microbes are associated with lower BP.	Verhaar et al. (2020)
	SHR models; two rat models of hypertension and a small cohort of patients was used for bacterial genomic analysis	Lactate-producing bacteria (Streptococcus and Turicibacter) were in higher quantities in the SHR, the F/B ratio was increased, a dysfunction in both acetogenic and butyrogenic capabilities.	HTN-associated dysbiosis is characterized as an accumulation of lactate-producing bacteria and a reduction of acetate and butyrate producers.	Yang et al. (2015)
	213 pregnant women, 11 women with pre-eclampsia (DPE), 202 controls	Women with DPE had significantly lower (alpha) diversity in their gut microbiota, and the SCFAs-producers, such as Coprococcus, Roseburia, Lachnospira, Butyricimonas, Unclassified Clostridiaceae, and Unclassified Clostridiales are reduced compared to the control group.	Reduced numbers of butyrate-producing bacteria in the gut microbiota induces lower circulating butyrate levels, influence SBP during early pregnancy.	Altemani et al. (2021)
	20 with HF due to frequent etiologies like ICMP and DCM, 20 healthy control subjects	Coriobacteriaceae, Erysipelotrichaceae and Ruminococcaceae, Blautia, Collinsella, uncl. Erysipelotrichaceae, and uncl. Ruminococcaceae showed a significant decrease, Escherichia/Shigella were enriched in HF cases. The pattern of depleted genera Blautia and Collinsella seems to be HF specific.	Intestinal epithelial dysfunction led to increasing permeability, possibly induced a bacterial shift and given rise to systemic inflammation.	Luedde et al. (2017)
Heart failure	60 well-nourished patients in stable condition with CHF; 20 matched healthy control subjects	Compared with normal control subjects, the entire CHF population had massive quantities of pathogenic bacteria and Candida, such as Campylobacter, Shigella, Salmonella, Yersinia enterocolitica, and Candida species.	Antimicrobial, hypoxia and acid/base disturbance, bowel ischemia, gastrointestinal dysmotility et al. may induce overgrowth of pathogenic bacteria and translocation.	Pasini et al. (2016)
	22 patients admitted for HF and 11 control subjects without a history of HF	Compared with control subjects, the phylum Actinobacteria and Bifiodobacterium was enriched whereas Megamonas was depleted, and plasma concentration of trimethylamine N-oxide (TMAO) was increased in HF patients; compared with the compensated HF patients, the decompensated HF had more abundant Escherichia/Shigella in the same patient.	An abundance of Escherichia/Shigella cluster means more TMA lyase (CutC/D) gene and higher circulating TMAO levels, implying certain bacteria harboring TMA lyases may enrich in the decompensated phase of HF.	Hayashi et al. (2018)

CAD, coronary artery disease; HTN, hypertension; pHTN, pre-hypertension; HELIUS, Healthy Life In an Urban Setting; SBP, systolic blood pressure; DBP, diastolic blood pressure; SHR, spontaneously hypertensive rat; HF, heart failure; ICMP, ischemic cardiomyopathy; DCM, dilated cardiomyopathy; CHF, chronic heart failure; DPE, pre-eclampsia.