Research advances and application prospects of CAR-T therapy in the treatment of age-related diseases

Abstract

Cellular senescence constitutes the core biological basis of body aging. It not only directly drives the occurrence and progression of multiple age-related diseases, but also establishes and maintains a chronic inflammatory microenvironment through the senescence-associated secretory phenotype (SASP), thereby continuously exacerbating tissue functional decline. In recent years, CAR-T cell therapy, as the first revolutionary therapy in cancer immunotherapy, has opened up new ways to intervene in age-related diseases with its excellent target elimination capabilities. This article first studies the molecular mechanisms of cellular senescence and its pathological effects. Then a systematic overview of the design principles, development trajectory and current applications of CAR-T technology is given, focusing on the latest experimental and clinical advances in aging-related cancers, neurodegenerative diseases and cardiovascular diseases. We also dive into key current challenges, including immune-senescence, target reliability, and treatment safety. Finally, we will explore the future optimization direction of CAR-T therapy and its translational potential through various strategies such as engineered immune cells and combination therapy, hoping to provide valuable insights into research and clinical practice in this field.

1. Introduction

The global population is aging at an unprecedented rate. At the same time, the incidence of age-related diseases such as cancer, Alzheimer’s disease, and cardiovascular disease continues to increase, which poses severe challenges to the medical system and socioeconomic stability. (1, 2). Cellular senescence is a key factor in aging and age-related diseases (3). The core features of cellular senescence are irreversible cell cycle arrest and release of the senescence-associated secretory phenotype (SASP) (4–6).This process not only directly damages the self-renewal and repair capabilities of tissues, but also establishes a persistent inflammatory microenvironment that accelerates the aging of surrounding normal cells, thereby leading to the occurrence and progression of various diseases (7). Eliminating or modulating senescent cells could extend healthy lifespan and reduce the incidence of age-related diseases in laboratory animals, study shows (8). For a long time, the mainstream anti-aging strategies have mainly been to regulate metabolic pathways or use senescent cell clearance drugs to clear senescent cells. However, these methods often lack specificity and are associated with significant side effects, thus limiting their clinical application. In recent years, the emergence of CAR-T cell therapy has provided a new approach to address this challenge (9, 10). CAR-T therapy genetically engineers T cells to express a chimeric antigen receptor (CAR). This receptor can specifically recognize tumor antigens and has shown significant efficacy in a variety of hematological malignancies (such as acute lymphoblastic leukemia and diffuse large B-cell lymphoma). (11). Its core advantage lies in its precise identification and removal of target cells. This property has inspired researchers to explore its potential applications in age-related diseases. This article systematically reviews the latest research progress of CAR-T therapy in the treatment of age-related diseases. We started from the molecular mechanism of aging and integrated the technical principles and development history of CAR-T therapy. This article also provides an outlook on the clinical transformation potential and challenges of CAR-T (Figure 1).

Figure 1.

Applications of CAR-T therapy in aging-related disorders. Cancer (tumors): CAR-T cells recognize surface antigens on cancer cells and induce tumor-cell death. Kidney disease (nephrosclerosis): CAR-T therapy holds promise for slowing the progression of renal-function decline. Alzheimer’s disease: Elimination of aberrant cells improves cognitive behavior in animal models, post-treatment reductions in cerebral immune dysregulation and improved clinical status have been reported. Progressive multiple sclerosis: CAR-T therapy attenuates immune dysregulation and alleviates clinical symptoms. Heart failure / cardiac fibrosis: Decreases aortic plaque area, lowers fibrotic burden, and improves cardiac function. Fatty liver disease: Reduces hepatic fibrosis and ameliorates metabolic function. Diabetes: Targets and clears senescent metabolic cells, restoring metabolic homeostasis. 有潜在potentiol.

2. Molecular mechanisms and pathological effects of cellular senescence

When cells encounter various stressors such as DNA damage, progressive telomere shortening, or oxidative stress, they often enter an irreversible state of growth arrest, commonly referred to as cellular senescence (12, 13). At this stage, cells not only stop dividing but also undergo morphological changes, a gradual functional decline, and massive release of the senescence-associated secretory phenotype (SASP) (14). The continuous accumulation of these senescent cells is considered a key driver of systemic aging and related diseases. The entire regulatory network is highly complex, involving cross-interactions among multiple signaling pathways. Its pathological effects arise both from the intrinsic dysfunction of senescent cells and from their paracrine disruption of the surrounding tissue microenvironment, ultimately compromising healthy tissue homeostasis (15).

2.1. Molecular regulatory mechanisms of cellular senescence

2.1.1. Telomere attrition and telomerase regulation

Telomeres are located at the ends of chromosomes and play a crucial protective role. Telomere length is regarded as a biological clock, reflecting cellular age and health status. As cells undergo repeated divisions, telomeres gradually shorten. Once they reach a critical threshold, the DNA damage response (DDR) pathway is activated, prompting cells to enter a senescent state (16). Furthermore, numerous epidemiological studies indicate that telomere attrition is significantly correlated with aging, morbidity, and mortality (17). Telomerase can extend telomeres through its reverse transcriptase activity. However, in most somatic cells, this enzyme remains repressed, it is highly expressed only in stem cells, germ cells, and certain tumor cells (18).

In HIV-infected individuals, markedly shortened telomeres are observed in peripheral blood T cells. This change positively correlates with increased CD57+CD8+ T cell proportion, a hallmark of immune senescence, suggesting telomere attrition likely represents a key mechanism underpinning accelerated aging in HIV infection (19, 20). In Alzheimer’s disease (AD) mouse models, reduced telomerase activity within neurons leads to further telomere shortening, accelerating neuronal senescence accompanied by cognitive decline. Conversely, telomerase overexpression delays this pathological process (21).

2.1.2. Core roles of p53-p21 and p16-Rb pathways

The p53-p21 and p16-Rb pathways represent two of the most critical regulatory pathways in cellular senescence, working in concert to maintain stable cell cycle progression. When cells encounter stress signals such as DNA damage or oxidative stress, the ATM/ATR kinase is activated, promoting the phosphorylation and nuclear translocation of p53 (tumor protein P53). This subsequently drives the expression of its downstream target gene p21 (a CDK inhibitor (22).p21 effectively blocks progression into the S phase by inhibiting cyclin-CDK complex activity, thereby inducing senescence. Meanwhile, p16 suppresses CDK4/6 activity, preventing phosphorylation of the Rb protein and inhibiting E2F transcription factor function, ultimately leading to cell cycle arrest (6).

Abnormal activation of these two pathways is prevalent in various age-related diseases. For instance, peripheral blood mononuclear cells from HIV-infected individuals exhibit markedly elevated p53 and p21 expression levels, closely associated with increased cardiovascular disease risk (23). In animal models of liver fibrosis, hepatic stellate cell senescence depends on activation of the p16-Rb pathway, while inhibiting p16 expression significantly reduces the accumulation of senescent cells, thereby alleviating the fibrotic process (24). Δ133p53 isoforms serve as effective regulators of the p53 pathway, governing critical functions in cancer, physiological and premature aging, neurodegenerative diseases, immunity and inflammation, and tissue repair. Recent research revealed that Δ133p53α counteracts the pro-aging effects induced by full-length p53 proteins, helping cells maintain proliferative capacity (25).

2.1.3. Regulation and effects of the senescence-associated secretory phenotype

One of the most striking features of senescent cells is their release of a complex array of factors. These factors are collectively known as the senescence-associated secretory phenotype (SASP). SASP is not a single molecule, but a complex mixture, including inflammatory cytokines such as IL-6 and IL-8 (26), chemokines such as CXCL9 and CCL2, and various matrix metalloproteinases (MMPs). They influence the microenvironment surrounding cells through paracrine effects. For example, members of the TGF-β family, vascular endothelial growth factor (VEGF), and chemokines such as CCL2 and CCL20 can propagate senescence to adjacent normal cells. This process is called paracrine senescence (27). In addition, SASP factors (such as IL-6) can act on senescent cells themselves through an autocrine mechanism, promoting cell cycle arrest and strengthening their senescent state (28). The SASP comprises numerous pro-inflammatory factors (e.g., IL-1, IL-6, IL-8, MCP-1), which can persistently activate the immune system, leading to localized or systemic chronic inflammation. This phenomenon is called “inflammatory aging”. This chronic inflammation not only promotes the accumulation of senescent cells, but is also closely associated with various age-related diseases (e.g., atherosclerosis, diabetes, and neurodegenerative diseases) (29). The expression of SASP is finely regulated by multiple signaling pathways, among which the NF-κB and MAPK pathways are particularly important (30, 31). Specifically, sustained activation of NF-κB is thought to be a core driver of initiation and maintenance of SASP (32). The effect of SASP is affected by time: in the short term, it promotes the recruitment of immune cells to clear senescent cells and exert beneficial physiological functions (33, 34). However, in the long term, the chronic inflammatory state it induces will “contaminate” the surrounding environment, prompting normal cells to enter a senescent state and driving pathological changes such as tissue fibrosis. (35). Recent research also points to metabolic regulation. A study using metabolomics showed that efficient SASP secretion relies on mitochondrial metabolic reprogramming. Inhibiting the activity of pyruvate dehydrogenase kinase (PDK) in mitochondria significantly attenuates the release of SASP, which provides a new potential therapeutic target for SASP-related diseases (36) Figure 2.

Figure 2.

Molecular circuitry driving cellular senescence. Healthy cells exposed to DNA damage, oxidative stress, telomere erosion or other insults transit into a senescent state. (A) Telomere attrition and telomerase control Telomeres (chromosome-end structures) progressively shorten, propelling cells toward senescence. (B) Central role of the p53-p21 and p16-Rb axes Stress signals activate p53 → p21 and p16 → hypophosphorylated Rb (hypo-Rb) → E2F pathways; both routes inhibit cyclin-CDK complexes, impose cell-cycle arrest and trigger senescence. (C) Regulation and impact of the senescence-associated secretory phenotype (SASP) Senescent cells release SASP factors that reinforce their own senescence (autocrine loop) and, via paracrine action, propagate senescence to neighboring cells; SASP additionally fuels chronic low-grade inflammation (inflammaging).

2.2. Pathological effects of cellular senescence and age-related diseases

2.2.1. Bidirectional regulation between aging and tumors

Aging has a dual effect on tumors, both inhibiting and promoting their progression. Although it can prevent the uncontrolled proliferation of potential cancer cells. However, over time, the accumulation of senescent cells and the release of SASP may reshape the tumor microenvironment (TME), induce angiogenesis and lead to immune suppression. Ultimately, this promotes tumor evolution and metastasis (37) (38). When cells encounter carcinogenic stimuli (such as DNA damage, oncogene activation), the senescence program can be initiated. Through pathways such as p53-p21 and p16-Rb, these programs induce stable cell cycle arrest, blocking the unlimited proliferation of potentially cancerous cells and forming the first “natural barrier”. At the same time, certain SASP factors (such as IL-15, CXCL1) can recruit and activate macrophages, NK cells, and T cells to enhance immune surveillance to help eliminate precancerous cells (38). However, in chronic lymphocytic leukemia (CLL), the expression of senescence-related markers (such as CD28 and CD57⁺) on the surface of patients’ T cells is significantly elevated. The immune function of these cells is impaired, so the ability to monitor and eliminate cancer cells is weakened, thereby promoting tumor escape (39, 40). In solid tumors such as prostate cancer and glioblastoma, senescent fibroblasts in the tumor microenvironment continue to secrete SASP factors, including IL-6 and MMP9. These molecules powerfully drive tumor cell invasion and distant metastasis (41).

2.2.2. Aging and neurodegenerative diseases

It is well established that progressive neuronal loss and pathological protein aggregation represent two core pathological alterations in neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) (42). Increasing evidence indicates that senescence occurring in multiple brain cell types, including neurons and microglia, likely serves as a key driver of disease progression. For instance, in AD mouse models, β-amyloid (Aβ) not only directly induces neuronal senescence but also triggers senescence responses in microglia. These senescent microglia, on one hand, secrete large amounts of inflammatory SASP factors such as TNF-α and IL-1β, exacerbating the neuroinflammatory environment. On the other hand, their ability to clear Aβ is significantly diminished. Such dual effects creates a vicious cycle, senescence-inflammation-protein deposition, that continuously drives disease progression (43). This cycle similarly applies to PD. Recent research indicates that senescence is the primary risk factor for PD, with mechanisms driving senescence promoting neurodegeneration in the disease. In PD animal models, aged microglia exhibit hyperactivated NF-κB signaling, releasing SASP factors like IL-1β and TNF-α that in turn exacerbate DA neuron apoptosis (44). Future interventions targeting this cycle in the preclinical stage, such as senescent cell clearance, restoration of protein homeostasis, or energy metabolism reprogramming, hold promise for simultaneously delaying the onset and progression of both AD and PD. The MS (multiple sclerosis) phenotype is closely linked to chronological age and immune senescence. Physiological aging and inflammation-induced cellular senescence lead to oligodendrocyte pathology in inflammatory demyelinating diseases like MS, suggesting that age drives disease progression (45). Recent studies also indicate that in HIV-associated neurocognitive disorder (HAND), the HIV-1 Tat protein binds to TLR7 receptors within microglial endosomal lysosomes, triggering lysosomal damage and ultimately inducing cellular senescence (46).

2.2.3. Senescence and cardiovascular disease

Cardiovascular disease has become the main cause of death in the elderly population, and more and more studies have shown that the aging of vascular endothelial cells and smooth muscle cells plays a key role in this process (47). HIV-infected patients receiving long-term combination antiretroviral therapy have significantly increased risk of cardiovascular disease (48). This additional risk may be due to certain nucleoside reverse transcriptase inhibitors (NRTIs). These drugs interfere with endothelial cell mitochondrial function, accelerate telomere shortening, and ultimately promote cellular senescence (49). For example, drugs such as tenofovir can inhibit mitochondrial DNA polymerase gamma activity, leading to accumulation of mitochondrial DNA mutations and increased levels of oxidative stress. These changes activate the p53-p21 signaling pathway and induce cellular senescence (6, 50). Notably, supplementation with mitochondria-targeted antioxidants (such as MitoQ) can partially alleviate drug-induced endothelial dysfunction, thereby delaying cellular senescence, suggesting its potential therapeutic value. (51). Senescent macrophages within plaques also play a deleterious role during atherosclerosis progression. By secreting SASP factors such as IL-6 and CXCL10, they continuously recruit more inflammatory cells and promote lipid deposition, thus exacerbating plaque instability (52). Although aging itself does not cause heart failure, age-related changes likely lower the threshold for manifesting heart failure signs and symptoms. Accumulation of DNA damage and telomere attrition results in an increase in cellular senescence and apoptosis, resulting in a decrease in the number and function of cells, contributing to the overall tissue and organ dysfunction (53).

2.2.4. Aging and kidney disease

As we age, the number of senescent cells in the kidneys increases, and age-related kidney diseases become increasingly common. In patients with end-stage renal disease, signs of aging kidney function appear earlier and are more pronounced than in healthy individuals (54). It now appears that cellular senescence in kidney cells is likely to be the core mechanism driving the aging of the entire organ. Cellular senescence may not only play a role in kidney aging but may also be involved in the pathogenesis of kidney disease (55). However, it is important to note that aging itself does not directly cause kidney disease; rather, the structural and functional changes that occur in the kidney during aging may increase susceptibility to kidney disease. Existing data suggest that cellular senescence is both a marker and driver of chronic kidney disease. (56). For example, renal tubular epithelial cell senescence is a key cellular event in the progression of acute kidney injury (AKI). It promotes the transformation of AKI to chronic kidney disease through SASP. Recent studies have further shown that tubular epithelial cell senescence accelerates the progression of renal fibrosis (57). Research also suggests that cellular senescence plays an important role in metabolism-related kidney disease. Although the exact causes and mechanisms of diabetic nephropathy remain unclear. However, existing evidence has shown that podocyte senescence plays a key role and is expected to become a new target for early intervention in chronic kidney disease (58). Preclinical studies have shown that senolytics that selectively eliminate senescent cells reduce renal fibrosis and maintain renal function in experimental models of fibrosis in the kidney and other organs. This suggests that cellular senescence may become a novel therapeutic target for kidney disease (54). Therefore, early detection and intervention are crucial to control the impact of cellular senescence on kidney disease. Future research should focus on developing more biomarkers that can detect signs of cellular aging in kidney tissue, with a view to enabling early intervention and treatment.

3. Technical principles and development history of CAR-T therapy

Chimeric antigen receptor T-cell (CAR-T) therapy represents a breakthrough in immunotherapy. This technology employs genetic engineering to modify a patient’s own or donor-derived T cells, causing them to express an artificially designed receptor, the CAR molecule (59). This receptor typically comprises a single-chain variable fragment (scFv) that recognizes specific antigens, a transmembrane domain, and an intracellular signaling domain responsible for activating T cells, thereby enables precise identification and elimination of cells bearing the target antigen (11). Since the world’s first CAR-T therapy drug, Kymriah, was approved in 2017 for pediatric acute lymphoblastic leukemia (60), this technology has demonstrated remarkable efficacy across multiple hematologic malignancies, including lymphoma and multiple myeloma. Its application scope continues to expand, from initial use in blood cancers to solid tumors, autoimmune diseases, and even showing potential therapeutic value in aging-related diseases in recent years.

3.1. Technical principles and structural optimization of CAR-T therapy

3.1.1. Structural composition of CAR molecules

The structure of a CAR molecule usually contains three functional components: an extracellular antigen-binding domain, a transmembrane domain, and an intracellular signaling domain (61, 62). First-generation CARs contained only the basic CD3ζ signaling domain, capable of initiating T cell receptor signaling but with limited activation efficacy and insufficient cytotoxicity against senescent cells (63). Second-generation CARs incorporated costimulatory molecules (CSMs) such as CD28 or 4-1BB, establishing a dual signaling pathway mediated by CD3ζ and CSMs, significantly enhanced T-cell proliferation and cytotoxic effects (64, 65). Currently the gold standard platform in senescence research. Both CD28 and 4-1BB co-stimulatory domains have been validated in preclinical models. For example, uPAR-targeted second-generation CAR-T cells (28ζ) demonstrated robust senolytic activity in liver fibrosis and age-related metabolic dysfunction models (66) (67). NKG2D-CAR-T cells (BBζ) effectively eliminated senescent neurons and glial cells in neurodegenerative disease models (68).Third-generation CARs further fuse two costimulatory molecules (e.g., CD28 and 4-1BB in series), thereby extending CAR-T cell survival in vivo. (69, 70).It shows enhanced T-cell expansion and persistence but may accelerate T-cell exhaustion in the chronic inflammatory environments typical of aging (71). Fourth-generation CARs, also known as TRUCKs, incorporate a cytokine-inducing domain that promotes cytokine production after antigen recognition. (70, 72, 73).It can have dual functions of target cell killing and cytokine secretion, but carry significant inflammatory risks in elderly populations (71). Fifth-generation CARs build upon the second-generation design by incorporating a truncated cytoplasmic IL-2 receptor β chain (IL-2Rβ) domain, activating the JAK-STAT signaling pathway. (74, 75).It can incorporate IL-2Rβ signaling to enhance T-cell stemness and metabolic fitness, which is particularly advantageous for overcoming immune senescence in elderly patients (76).

Different costimulatory signals significantly affect the aging behavior of CAR-T cells. CAR-T cells expressing the 4-1BB costimulatory domain (BBζ) exhibit increased p16 expression and impaired proliferation after repeated antigen stimulation, which are hallmarks of aging. In contrast, CAR-T cells using the CD28 costimulatory domain (28ζ) showed better anti-aging stability. (77).

3.1.2. CAR-T cell preparation workflow and optimization

The standard CAR-T cell preparation process usually begins with collecting peripheral blood from patients or healthy donors, followed by obtaining peripheral blood mononuclear cells (PBMCs) through leukapheresis. Next, anti-CD3/CD28 antibodies or immunomagnetic beads are used to activate T cells in vitro. Subsequently, the CAR encoding gene is introduced into T cells through viral vectors such as lentivirus or retrovirus, or non-viral methods such as transposon systems and mRNA electroporation. Under the stimulation of cytokines such as IL-2, IL-7 and IL-15, these engineered T cells undergo large-scale expansion. Finally, after the patient receives appropriate lymphocyte depletion pretreatment, CAR-T cells are reinfused to complete the treatment (78, 79).

In recent years, researchers have continuously optimized preparation strategies to improve the efficacy and durability of CAR-T products, with special emphasis on delaying cell aging. For example, using IL-21 to replace traditional IL-2 in in vitro culture helps CAR-T cells maintain a metabolic state dominated by oxidative phosphorylation (OXPHOS) and reduce their dependence on glycolysis. This approach reduces the expression of aging markers such as CD57 and p21, thereby delaying functional decline (80). In addition, CAR-T cells prepared using mRNA electroporation technology can achieve transient CAR expression. Although this method has a short duration of action, it can effectively avoid cell exhaustion and aging caused by long-term antigen stimulation (81). This type of “short-term expression” CAR-T cells has been proven to be safe and effective in clearing senescent cells in animal studies, providing a new strategy for clinical application. (82). Recent research indicates that aquaporin-mediated transfection yields 1.7 to 2 times higher CAR-T cell production compared to electroporation, with superior cell viability and recovery rates (83). Zhang et al. also developed a cardiolipin mimetic phosphoramide (CAMP) lipid that can transfect T cells without antibody modification. The lipid encapsulates the CAR-encoding circular RNA, further extending the duration of mRNA expression in mouse spleens and T cells (84). Figure 3.

Figure 3.

CAR-T cell manufacturing workflow. 1. T-cell acquisition: isolate autologous T cells from the patient’s peripheral blood. 2. CAR construction: introduce the chimeric-antigen-receptor (CAR) gene into T cells; the encoded CAR comprises an antigen-recognition domain plus signaling domains. 3. Expansion: culture the genetically modified T cells ex vivo to achieve clinically relevant numbers. 4. Infusion: reinfuse the expanded CAR-T product into the patient. Evolution of CAR architecture. All CAR generations share an extracellular scFv (antigen-recognition), a trans-membrane spacer, and intracellular signaling modules; they differ in the number and type of co-stimulatory/signaling domains: 1st generation: CD3ζ only. 2nd generation: CD3ζ + one co-stimulatory domain (e.g., CM1). 3rd generation: CD3ζ + two co-stimulatory domains (e.g., CM1 + CM2). 4th generation (TRUCK): 3rd-gen backbone + an inducible cytokine cassette (e.g., IL-12) that secretes immune-enhancing cytokines. 5th generation: 3rd-gen backbone + a cytokine-receptor signaling domain (e.g., IL-2Rβ) enabling JAK/STAT pathway activation.

3.1.3. Applicability of different CAR generations in senescent cell clearance

The design requirements for CAR-T cells targeting senescent cells differ fundamentally from those targeting tumor cells, driven by core biological differences between the two cell types. These differences directly determine the relative performance of different CAR generations in age-related disease applications.

Tumor therapy aims for long-term immune surveillance to prevent recurrence, whereas senolytic therapy requires transient, potent, and controlled cytotoxicity to avoid exacerbating chronic inflammaging in elderly populations (67) (71). Within this framework, second-generation CAR-T cells remain the current gold standard for senescence research and translation. The CD28ζ variant is the first choice for most age-related diseases, including liver fibrosis and metabolic dysfunction, owing to its rapid expansion, acute cytotoxicity, and low risk of chronic inflammation (66, 67).

To further quantify the relative advantages and disadvantages of different CAR generations in age-related diseases, we conducted a comprehensive risk-benefit analysis specifically tailored to elderly patients (Table 1). The data presented in this table are primarily derived from animal models and early clinical investigations, and large-scale human clinical trial data remain limited (71).

Table 1.

Risk-benefit analysis of different CAR generations in age-related diseases.

CAR generation	Core structural features	Performance in tumor therapy	Performance in senescent cell clearance	Key risks in aging populations	Recommended application scenarios in aging diseases
1st Generation	CD3ζ intracellular domain only	Obsolete (insufficient T-cell activation)	No reported applications	Low toxicity but no therapeutic efficacy	None
2nd Generation (CD28ζ)	CD3ζ + CD28 co-stimulatory domain	Excellent for hematological malignancies; rapid response but shorter persistence	Optimal; rapid cytotoxicity, minimal off-target effects, low risk of chronic inflammation	Mild CRS (grade 1–2 in <10% of patients)	Liver fibrosis, metabolic dysfunction, cardiovascular fibrosis
2nd Generation (BBζ)	CD3ζ + 4-1BB co-stimulatory domain	Superior persistence; better for preventing tumor recurrence	Good but suboptimal; increased T-cell senescence and long-term off-target risk	Higher risk of T-cell exhaustion and delayed toxicity	Neurodegenerative diseases (requires longer persistence)
3rd Generation	CD3ζ + 2 co-stimulatory domains (e.g., CD28 + 4-1BB)	Enhanced expansion and persistence; better for solid tumors	Moderate; prolonged activation may exacerbate inflammaging	Increased risk of chronic inflammation and ICANS	Severe organ fibrosis (limited to short-term treatment)
4th Generation (TRUCKs, IL-12)	2nd generation + cytokine secretion domain (IL-12)	Effective for solid tumors; modulates immunosuppressive TME	Poor; high inflammatory risk outweighs benefits	High risk of severe CRS/ICANS; potentially fatal in elderly	Not recommended for systemic use; only for local administration with inducible expression
5th Generation	2nd generation + IL-2Rβ domain	Promising for both hematological and solid tumors	Excellent potential; overcomes immune senescence	Limited clinical data; theoretical risk of uncontrolled T-cell proliferation	Elderly patients with severe immune senescence

3.2. Development history and current clinical applications of CAR-T therapy

3.2.1. Breakthrough advances in hematologic malignancies

The clinical application of CAR-T therapy in hematologic malignancies has reached relative maturity. Since its first clinical use in 2010, CAR-T cell therapy has demonstrated significant success in treating B-cell malignancies (85). By 2025, six CAR-T cell therapies had received approval from the FDA (U.S. Food and Drug Administration) and EMA (European Medicines Agency) globally for hematologic malignancies (11, 86). Idecalumab cell therapy (ide-cel) received FDA approval for treating relapsed refractory multiple myeloma (RRMM), becoming the first CAR-T product approved for multiple myeloma (87). Target molecules for hematologic malignancies primarily include CD19 (e.g., Kymriah, Yescarta) (88), BCMA (e.g., Abecma, Carvykti), and CD22 (89).Indications include acute lymphoblastic leukemia (ALL), diffuse large B-cell lymphoma (DLBCL), and multiple myeloma (MM) (11). Clinically, CD19-targeted CAR-T cells demonstrate high initial response rates in treating relapsed/refractory B-cell non-Hodgkin lymphoma patients, with remission rates reaching 70% to 90% (90). ssCART-19 is a novel autologous CD19-specific CAR-T therapy that incorporates shRNA technology to silence IL-6. It demonstrated favorable safety in a Phase I clinical trial for relapsed/refractory B-cell acute lymphoblastic leukemia (91). Actalycabtagene autoleucel, a novel humanized anti-CD19 CAR-T cell therapy, received Indian approval on October 13, 2023, for treating relapsed/refractory B-cell lymphoma and relapsed/refractory B-cell acute lymphoblastic leukemia, becoming the first domestically developed CAR-T product approved for marketing in India globally. refractory B-cell acute lymphoblastic leukemia (ALCL), becoming the world’s first domestically developed CAR-T product approved for marketing in India (92). Additionally, we found that the FDA-approved isocitrate dehydrogenase 2 (IDH2) inhibitor enasidenib enhances memory CAR T-cell formation and maintains anti-leukemic cytotoxicity in vivo (93).

3.2.2. Challenges and breakthroughs in solid tumors

Compared with hematological malignancies, the application of CAR-T cell therapy in solid tumors faces greater challenges. The main reasons are the high antigen heterogeneity in solid tumors, the tumor microenvironment (TME) inhibiting CAR-T cell function, and the difficulty of CAR-T cells effectively infiltrating solid tumors (94). These challenges are significantly amplified in elderly individuals due to age-related biological changes that synergize with tumor-intrinsic factors to further reduce CAR-T efficacy:progressive stromal fibrosis with aging exacerbates CAR-T cell infiltration defects. increased myeloid-derived suppressor cell (MDSC) infiltration in the aged tumor microenvironment (TME) amplifies immunosuppression.increased myeloid-derived suppressor cell (MDSC) infiltration in the aged tumor microenvironment (TME) amplifies immunosuppression (95, 96).This combination of poor manufacturing quality and enhanced in vivo dysfunction makes solid tumor CAR-T therapy particularly challenging in the elderly population. (97, 98).

In order to break through these technical bottlenecks, scientific researchers are promoting technology optimization through various channels. Solutions for tumor antigen heterogeneity and antigen loss include bispecific CAR-T cells (99), hybrid CAR-T cells (100), CAR-T cell switching technology (101), and radiomics (AI) (102). In addition, Baker and Roybal’s team recently developed an advanced engineered receptor for soluble cell communication and disease sensing. They successfully used this technology to guide CAR-T cells to specifically target and destroy solid tumors expressing soluble disease-related factors, thereby minimizing off-target toxicity. (103). To overcome the immunosuppressive tumor microenvironment, researchers have designed CAR-T cells that secrete immunostimulatory cytokines such as IL-12, IL-18, and IL-15 (104); CAR-T cells that target regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs) (105), and M2 macrophages; and programs that combine CAR-T cells with chemotherapy (106).We can also develop armored CAR-T cells that secrete immunostimulatory cytokines such as IL-12, IL-18 or IL-15 (such as IL-15/IL-21 autocrine circuit or CXCR2 chemokine receptor-modified CAR-T cells). These therapies maintain higher activity in the fibrotic microenvironment while promoting cross-infiltration of endogenous CD8⁺ T cells (107) (108). To enhance tumor infiltration of CAR-T cells, researchers have developed nanobody-based CAR-T therapies, CAR-T cells expressing chemokine receptors, locally administered CAR-T cells, CAR-T cells targeting stromal cell-associated antigens, CAR-T cells secreting matrix-degrading enzymes, molecular torpedoes, and CAR-T cell therapies in combination with immune checkpoint inhibitors (anti-CTLA-4 or anti-PD-1 monoclonal antibodies) (109). A recent study identified a synNotch receptor designed to bind to the brain-localized extracellular matrix protein BCAN. It can locally induce CAR expression targeting EphA2 and IL13Rα2, resulting in complete clearance of xenograft tumors derived from glioblastoma patients (110–112).

3.2.3. Expansion into non-oncological applications

In recent years, the application of CAR-T therapy has expanded from the field of oncology to autoimmune diseases, chronic infections and age-related diseases (113). In autoimmune diseases, CD19-targeted CAR-T cells have been used to specifically eliminate pathogenic B cells, and clinical studies are currently underway for diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) (114). CD19-CAR-T cells can profoundly eliminate CD19⁺ B cells within synovial tissue, including synovial infiltrating B cells that are difficult to eradicate with conventional monoclonal antibody therapy (115, 116) (117). In infectious diseases, A new technology based on CAR-T cell immunotherapy has demonstrated potential for clearing persistent infections (118). Liu et al. developed a broadly neutralizing antibody-derived (bNAb-derived) CAR-T cell therapy that can exert specific cytotoxic activity against HIV-1-infected cells, eliminate latently infected cells, and delay viral rebound (119). In age-related diseases, uPAR-targeted CAR-T cells have been shown to effectively eliminate uPAR-expressing senescent hepatocytes and activated hepatic stellate cells in the liver. The therapy significantly reduced the number of senescent cells, reduced fibrotic areas, and improved liver function, with no significant toxicity observed at low doses (67, 120).

3.2.4. Expanded applications in renal medicine

The application of CAR-T in kidney diseases has expanded from tumor-associated renal impairment (121) to autoimmune nephropathy, demonstrating significant potential, particularly in eliminating pathogenic B cells and restoring immune tolerance. Compared with other therapies, CAR-T therapy for multiple myeloma (MM) with renal impairment achieves tumor cell clearance while improving renal function (122). CD19-CAR-T cells effectively targeted and eliminated CD19+ B cells in lupus mouse models, reducing autoantibody secretion, alleviating lupus symptoms, and prolonging mouse survival (123). In another clinical study by Mackensen et al., five patients who had previously failed multiple treatments were enrolled; These patients demonstrated significant reductions in proteinuria and anti-dsDNA levels, along with elevated complement levels, three months after anti-CD19 CAR-T cell therapy (124). These data collectively indicate that CD19-CAR-T cell transfer is feasible, well-tolerated, and highly effective in Lupus nephritis. Substantial evidence suggests extensive B-cell involvement in the pathogenesis of AAV (ANCA-associated vasculitis). Recently, Dörte Lodka et al. investigated the potential of CD19-CAR-T cell therapy for AAV using a preclinical mouse model of MPO-AAV. The CAR-T cells targeted CD19+ B cells and plasma cells, reducing ANCA (anti-neutrophil cytoplasmic antibody) production and preventing necrotizing crescentic glomerulonephritis. Renal fibrosis is a hallmark of chronic kidney disease. Zhao et al. demonstrated that CAR-T therapy targeting ECM-producing cells alleviates fibrosis in chronic kidney disease, with anti-fibrotic effects also validated in human kidney organs. Unfortunately, no CAR-T applications currently exist for kidney aging-related diseases (125).

4. Research progress of CAR-T therapy in ageing-related diseases

In 2020, Amor C et al. engineered uPAR-CAR-T cells (using urokinase receptor as a universal senescence marker) (67). In models of liver fibrosis and lung adenocarcinoma-induced senescence, a single injection can achieve long-term clearance of senescent cells and restore tissue function, directly proving for the first time that “CAR-T can clear senescent cells.” Even more exciting is that uPAR-CAR-T cells can also improve age-related metabolic disorders and physical dysfunction. It maintains its long-lasting and preventive effects by activating memory CD8 T cells and effector CD8 T cells. (66).

The core mechanism underlying age-related diseases lies in the progressive accumulation of senescent cells within the body, which mediate persistent chronic inflammation by releasing the SASP. CAR-T therapy, with its ability to precisely identify and eliminate specific target cells, offers a novel approach to intervening in such diseases: it can directly target and clear pathological senescent cells (126), or be used to eliminate age-related abnormal cells such as tumor cells or overactive reactive immune cells. Next, I will introduce the latest developments in CAR-T therapy in this field from the perspective of different disease types, drawing on significant recent research.

4.1. Research advances in CAR-T for ageing-related tumors

Tumorigenesis is closely linked to aging, with incidence rates significantly increasing with age (127). The tumor microenvironment usually contains a large number of senescent cells, such as senescent fibroblasts and immune cells, which promote tumor progression and immune suppression by secreting SASP.CAR-T therapy can not only selectively eliminate tumor cells, but also effectively reduce pathological senescent cells by identifying specific surface markers on these cells, thereby improving the overall treatment effect.

In hematological malignancies, patients often exhibit significant immune senescence, which is manifested by shortened telomeres, increased proportion of CD57-positive cells, and weakened function of T cells. These changes will reduce the efficacy of CAR-T cells (128). Genetic engineering of CAR-T cells can enhance their anti-aging properties. For example, overexpression of the anti-aging p53 isoform Δ133p53α in CD19-CAR-T cells inhibits senescence signaling pathways, enhances CAR-T cell function, and improves the remission rate of acute lymphoblastic leukemia (ALL) mouse models (129).

The efficacy of CAR-T cells against solid tumors remains limited, hindered by antigenic heterogeneity, immune evasion mechanisms, and the immunosuppressive tumor microenvironment (TME) (130).These challenges are particularly pronounced in elderly patients, where age-related biological changes further compound treatment disparities. This disparity was independently associated with three age-specific factors: higher intratumoral collagen content, increased MDSC infiltration, and more severe autologous T cell senescence (96, 131).Senescent fibroblasts in the solid tumor microenvironment promote tumor invasion and suppress immune responses by secreting SASP factors such as IL-6 and matrix metalloproteinases (MMPs) (132). CAR-T therapy targeting these senescent stromal cells, in combination with conventional tumor-targeted CAR-T, can improve the tumor microenvironment and enhance anti-tumor immune responses in elderly patients. (133).

4.2. Research progress of CAR-T in neurodegenerative diseases

Neurodegenerative diseases (NDDs), including Alzheimer’s disease (AD), Parkinson’s disease (PD), and multiple sclerosis (MS), are the leading causes of physical and cognitive impairment worldwide (134). Neuronal loss and persistent neuroinflammation are the common pathological basis of Alzheimer’s disease (AD) and Parkinson’s disease (PD). Among them, the aging of brain cells such as neurons and microglia is considered a key driver of this process (135, 136). In recent years, CAR-T therapy has emerged as a potential intervention strategy due to its precise targeting ability, but its application in NDDs remains in the very early preclinical stage with significant translational challenges.

In Alzheimer’s disease, Aβ plaques and hyperphosphorylated tau protein deposition are a significant pathological feature, causing neurons and microglia to enter a senescent state. The FDA and EMA recently approved three monoclonal antibodies against Aβ. However, they only slow cognitive decline by about 30% (137). Given the limitations of passive immune strategies in AD, cell therapy has emerged as an attractive alternative. Using mouse embryonic fibroblasts (MEFs) and astrocytes (AST) as aging models, Deng et al. demonstrated that NKG2DL expression is elevated under genotoxicity and oxidative stress. NKG2D-CAR T cells exhibited potent cytotoxicity against these senescent cells and had little effect on non-senescent cells (68).In addition, CAR-T cell therapy targeting tau protein is under research. The therapy may reduce neurofibrillary tangle formation and protect neuronal function by clearing hyperphosphorylated tau protein (138). All current senolytic CAR-T studies for AD are preclinical, and none have entered clinical trials. Although aging accelerates the progression of Parkinson’s disease (PD), there are currently no clinical studies or animal experiments that directly verify the application of CAR-T cell therapy in the treatment of PD. Multiple sclerosis (MS) is not a typical age-related degenerative disease, but its onset and progression are closely related to age-related immune dysregulation. Fischbach et al. demonstrated that CD19 CAR-T cells not only suppress inflammatory relapses in MS patients, but also eliminate disease-promoting B cells residing in the central nervous system (139). In a clinical trial by Qin et al., five patients with progressive multiple sclerosis (PMS) were treated with anti-B-cell maturation antigen chimeric antigen receptor T (CAR-T) cell therapy. They observed clinical remission in patients, long-term expansion of CAR-T cells, and reduced cell depletion in the cerebrospinal fluid. (140).These findings suggest that CAR-T therapy may have potential for immune-mediated neurological diseases associated with aging. (68).

4.3. Research advances in CAR-T therapy for cardiovascular diseases

Cardiovascular disease is the leading cause of death among the elderly, closely associated with the progressive aging of vascular endothelial cells, smooth muscle cells, and cardiomyocytes (47, 141).In recent years, CAR-T therapy has emerged as a new treatment method. It slows disease progression by precisely eliminating specific cells, targeting aging vascular cells or pro-inflammatory immune cells. In atherosclerosis, abnormal lipid deposition combined with chronic inflammatory responses drive plaque formation. Among them, senescent endothelial cells (142) and macrophages (143) play key roles. CAR-T cells can target uPAR expressed on senescent macrophages, inducing senescent cell death. This approach holds promise for alleviating chronic inflammation in atherosclerosis, stabilizing plaques, and delaying disease progression (52). In vitro and in preclinical mouse models, CAR-T cells can also target macrophages, reducing oxLDL uptake and foam cell formation (144). The progression of heart failure is frequently accompanied by myocardial cell senescence and progressive fibrosis. Senescent cardiac fibroblasts accelerate myocardial remodeling and functional deterioration through excessive secretion of collagen and multiple SASP factors (145). In a stress-overload-induced heart failure mouse model, these cells highly express fibroblast activation protein (FAP) (146). Application of FAP-CAR-T cells specifically eliminates senescent fibroblasts, significantly reducing cardiac interstitial collagen deposition and improving cardiac function (147). In the original study by Aghajanian et al. (148) (148), FAP-CAR-T treatment did not cause significant systemic toxicity, weight loss, or histopathological damage to normal organs in mice, despite detectable CAR-T cell infiltration into the bone marrow. Similarly, the mRNA-based FAP-CAR-T approach showed no evidence of off-target toxicity in preclinical models, likely due to the transient nature of CAR expression (149).While these preclinical results are highly promising, it is important to note that all studies to date have been conducted in small animal models, and further validation in large animal models and human clinical trials is required.

Another critical translational challenge is whether transient CAR-T cell persistence is sufficient for the management of chronic cardiovascular disease or whether repeated dosing would be required. Both the conventional DNA-based FAP-CAR-T and the mRNA-based transient CAR-T approaches produced durable improvements in cardiac function despite limited CAR-T persistence. This suggests that a single, targeted depletion of activated myofibroblasts may be sufficient to interrupt the self-sustaining fibrotic cascade and allow endogenous tissue repair mechanisms to restore cardiac function. Unlike cancer, where long-term CAR-T persistence is often required to prevent relapse, cardiac fibrosis is a progressive but potentially reversible process (150). Once the pathological fibroblast population is eliminated and the pro-fibrotic microenvironment is normalized, residual fibroblasts can return to a quiescent state, and ongoing ECM deposition is halted. However, for patients with advanced chronic heart disease or recurrent injury (e.g., repeated MIs), repeated dosing may be necessary to maintain therapeutic efficacy. The mRNA-based CAR-T platform is particularly well-suited for repeated administration because it avoids the risk of insertional mutagenesis, does not induce long-term CAR-T cell memory, and allows for precise dose titration and treatment discontinuation if toxicity occurs (151).

4.4. Research advances in CAR-T for metabolic diseases

Metabolic diseases such as diabetes and non-alcoholic fatty liver disease (NAFLD) are closely associated with the body’s aging process. The senescence of functional cells like adipocytes and hepatocytes often triggers insulin resistance and lipid metabolism disorders, thereby accelerating disease progression (152).In recent years, CAR-T therapy has been gradually used to intervene in metabolic aging due to its potential to precisely eliminate specific cells. Targeted elimination of senescent metabolic cells provides a new approach to restore metabolic homeostasis. Preclinical studies have shown that redirecting CAR-T cells to pancreatic beta cells can prevent beta cell destruction, thereby preventing the onset and progression of diabetes in mouse models (153).CAR-T cells targeting uPAR-positive cells improved metabolic dysfunction and glucose tolerance in aged mice and high-fat diet-fed mice (66). In NAFLD, hepatocyte senescence and abnormal activation of hepatic stellate cells are key mechanisms driving disease progression (120, 154). Studies indicate significantly elevated uPAR expression on senescent hepatocyte surfaces. Utilizing uPAR-CAR-T cells to specifically eliminate these cells markedly reduced collagen deposition and improved liver function, with no apparent toxicity observed at low doses (155). In a non-alcoholic steatohepatitis (NASH) model, m.uPAR-h.28z CAR-T cells demonstrated regulatory effects on cellular senescence, effectively reversing liver fibrosis (67). CAR-T cells targeting FAP can eliminate profibrotic hematopoietic stem cells and regulate immune cells, endothelial cells and liver cells, thereby reducing inflammation and restoring liver homeostasis, significantly reducing liver fibrosis (156).

5. Challenges and optimization strategies for CAR-T therapy in age-related diseases

CAR-T therapy has shown great potential in treating age-related diseases, but its practical application faces multiple challenges. Challenges include cellular dysfunction caused by immune-senescence, insufficient targeting specificity, safety risks (such as cytokine release syndrome and neurotoxicity), and complex manufacturing processes (157).

5.1. Patient immune senescence

A Fundamental Barrier to CAR-T Therapy for Age-Related Diseases is the impact of host aging itself on CAR-T therapy efficacy represents the most critical unaddressed challenge in translating senolytic CAR-T technology to elderly patients, who constitute the primary population affected by age-related diseases. This barrier manifests at three interconnected levels: inferior clinical outcomes in elderly cohorts, intrinsic defects in autologous T cells from aged donors (158), and impaired in vivo function of CAR-T cells in the aged immune microenvironment (159).

5.1.1. Clinical trial outcomes of CAR-T therapy specifically in elderly patients

Elderly patients (≥65 years) account for >60% of newly diagnosed hematologic malignancies and nearly all age-related degenerative diseases (160, 161), yet they have been historically underrepresented in early CAR-T clinical trials. Recent dedicated analyses and large-scale real-world studies have confirmed that CAR-T therapy retains significant efficacy in this population, but with distinct safety and durability profiles.

In hematologic malignancies (the most clinically advanced indication), CAR-T therapy achieves comparable response rates in elderly and younger patients, albeit with slightly elevated toxicity risk. In the pivotal ZUMA-1 trial of axicabtagene ciloleucel for refractory large B-cell lymphoma, patients ≥65 years (n=51) achieved an overall response rate (ORR) and complete response (CR) rate, which were non-inferior to younger patients (162). The JULIET trial of tisagenlecleucel similarly reported an ORR in patients ≥65 years, with no significant difference in 12-month overall survival (OS) compared to younger cohorts (163). For relapsed/refractory multiple myeloma, the KarMMa trial of idecabtagene vicleucel showed that patients ≥65 years had an ORR of 73% and CR of 33%, nearly identical to younger patients, with comparable 12-month progression-free survival (PFS) (164). Baseline immune senescence markers were identified as independent predictors of both treatment efficacy and toxicity in elderly cohorts (165).

5.1.2. Preclinical mechanisms of age-related CAR-T dysfunction

Preclinical studies have systematically elucidated how the aged host immune environment impairs CAR-T therapy at three key stages: manufacturing, in vivo expansion, and long-term persistence.

Autologous T cells from elderly individuals have intrinsic functional defects that significantly reduce manufacturing success rates and product quality (98). Elderly donors exhibit reduction in naive T cell numbers and a marked expansion of terminally differentiated CD57⁺CD28⁺ T cells. These cells are resistant to anti-CD3/CD28 activation and are more prone to apoptosis during in vitro expansion, leading to lower CAR-T production yields and higher rates of manufacturing failure (166).

The aged systemic immune environment significantly impairs the early expansion phase of infused CAR-T cells, which is a key determinant of therapeutic efficacy. Standard fludarabine/cyclophosphamide lymphodepletion conditioning achieves lower efficacy in aged mice compared to young mice, leaving higher residual numbers of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) that potently inhibit CAR-T proliferation (166, 167).

Aged hosts fail to support the development of long-lived CAR-T memory cells, leading to higher relapse rates and reduced durability of response. In aged mouse models, infused CAR-T cells preferentially differentiate into short-lived effector T cells (CD62L⁺CD44⁺) rather than central memory T cells (CD62L⁺CD44⁺), resulting in reduction in CAR-T cell numbers (168).Senescent stromal cells and M2 macrophages in aged tissues secrete high levels of TGF-β and IL-10, which induce CAR-T cell senescence and apoptosis.

5.1.3. Optimization strategies to overcome age-related CAR-T dysfunction

Immune senescence represents age-related immune dysfunction characterized by reduced T cell diversity, diminished effector function, and increased expression of senescence markers. In elderly patients, autologous T cells often exhibit advanced senescence, leading to poor CAR-T cell preparation efficiency and limited expansion capacity (169).This issue is particularly critical for solid tumor CAR-T therapy, where aged T cells must not only survive ex vivo manufacturing but also function effectively in the highly immunosuppressive and fibrotic TME of elderly patients.

Three primary strategies exist for restoring the T cell repertoire: replacement, reprogramming, and rejuvenation of senescent cells (170). Corresponding improvement strategies include: utilizing allogeneic T cell sources, such as umbilical cord blood or T cells differentiated from induced pluripotent stem cells (iPSCs). These cells possess longer telomeres and lower expression of senescence markers, significantly enhancing CAR-T expansion capacity and persistence in elderly individuals (171, 172); Genetically enhancing anti-aging properties, such as overexpressing telomerase reverse transcriptase (TERT) to extend telomeres or knocking out aging-related genes like p16 (173); Restoring and maintaining thymic microenvironments through bioengineered thymic organoids combined with growth promoters and cytokines (e.g., IL-21) to reverse thymic atrophy effects. IL-21 has recently been identified as a thymic stimulatory factor that triggers thymopoiesis in aged mice, demonstrating significant immune restoration and rejuvenation of peripheral T cell pools (174, 175).

5.2. Target specificity and off-target toxicity

The specificity of target selection directly impacts CAR-T therapy safety. Current markers for identifying senescent cells (e.g., uPAR, NKG2DLs) are also expressed at low levels in normal tissues, potentially causing off-target toxicity. Current strategies to enhance specificity primarily include: designing bispecific CARs or multi-target CAR-T cells, including tandem CAR-T cells (176). Developing conditionally activated CAR systems, such as those utilizing hypoxia response elements (HREs), enables CAR activation exclusively in hypoxic microenvironments like tumors or fibrotic tissues, avoiding activation in normal tissues (177). Additionally, novel targets with higher senescence specificity can be explored. Another study identified the glycolipid antigen GD3 as a specific marker for senescent cells (178). GD3 CAR T cells target, limit and treat spontaneous tumor in aging Tsc2+/– mice (179). Sun et al. found that CD24-CAR-T cells blocked the CD24-Siglec-10 pathway, thereby enhancing the ability of macrophages to phagocytose and clear myeloma cells, and had better efficacy in the treatment of MM than BCMA-CAR-T cell therapy. (180) Table 2.

Table 2.

Specific target selection for CAR-T therapy.

Target antigen	Animal model	Organ	Conclusion	Author
uPAR	Mouse liver fibrosis aging model;senescence model of lung adenocarcinoma in mice	Liver and lung	Ablate senescent cells	(67)
uPAR	Natural aging mouse model;Metabolic aging model induced by HFD	Liver, adipose tissue, pancreas	Ameliorates metabolic dysfunction	(66)
NKG2D	Senescent mouse model	Brain	Target senescent brain cells	(68)
BCMA/CD24	Human MM cell lines xenograft mouse model	Multiple myeloma	Control growth	(180)
CD5/CD7	Mouse xenograft model	T cell malignancies	Mitigate tumor antigen escape	(Dai et al. 2022)
CD33/CLL-1	U937-Luc xenograft NSG mouse model	B cell malignancies	Ttreat acute myeloid leukemia	(114)
FOLR1/MSLN	Subcutaneous SKOV3 xenograft model in B-NDG mice	Ovarian	Enhance antitumor effects	(Liang et al. 2021)
Her2	Nude mouse tumor transplantation model	Liver	Safe tumor suppression	(Xue et al. 2018)
GD3	TSC2 gene knockout tumor cell inoculated mouse model;Spontaneous Tumor Model in TSC2 Heterozygous Mice	Liver and kidney	Target  tumors	(179)
CD24	5TGM1/KaLwRij MM mouse models	Myeloma	Reduce MM burden	(180)

This table summarizes representative preclinical studies investigating novel target antigens for chimeric antigen receptor T-cell (CAR-T) therapy, focusing on senolytic applications, hematological malignancies, and solid tumors..

5.3. Safety risks and management

Cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and off-target effects represent major safety risks in CAR-T therapy. Elderly patients, with reduced multi-organ functional reserve, exhibit poorer tolerance to these toxicities. CRS is the most common toxicity associated with CAR-T cell therapy, presenting symptoms ranging from mild to life-threatening (181). CRS management follows the principle of “prevention-oriented, tiered intervention, and multi-pronged approach.” Among these, targeted therapy against the IL-6 signaling axis is the current standard treatment strategy for CRS (182), effectively alleviating symptoms and improving patient prognosis. In 2019, the American Society for Transplantation and Cellular Therapy released updated guidelines establishing a unified consensus grading system for CRS and neurotoxicity (183). ICANS occurs less frequently and typically presents later than CRS. The pathophysiology and management of ICANS remain unclear, but pre-infusion immune profiling may alter susceptibility to ICANS (184). Notably, blocking the IL-6 receptor system appears ineffective for ICANS (185), whereas inhibiting myeloid mediators such as IL-1 may improve neurotoxicity in mouse models (186–188) and may hold clinical relevance (Park et al.). A deeper understanding of the immune response after CAR-T cell infusion will help improve clinical management and strengthen our research on CAR-T cell activation or depletion, reducing post-infusion risks.

Notably, the risk of CRS and ICANS is significantly higher in elderly patients receiving fourth-generation IL-12-secreting CAR-T cells (189). The pre-existing inflammaging state in elderly patients creates a synergistic effect with CAR-T-secreted IL-12, leading to exaggerated inflammatory responses. To address this specific risk, we recommend the following age-specific safety optimization strategies: (1) avoid systemic administration of IL-12-secreting CAR-T cells in elderly patients; (2) use inducible promoter systems to restrict cytokine secretion to the target tissue; (3) replace IL-12 with less pro-inflammatory cytokines such as IL-15 or IL-21; and (4) implement low-dose fractionated infusion protocols to prevent sudden cytokine surges. (126, 190, 191).

5.4. Manufacturing complexity and accessibility

Existing CAR-T therapies heavily rely on autologous T cells, involving complex preparation processes, extended timelines (typically 2–4 weeks), and high costs (exceeding $500,000 per treatment) (192). Additionally, elderly patients often exhibit reduced T-cell numbers and diminished quality, increasing preparation failure. To address autologous dependency, universal allogeneic CAR-T cells can be developed by knocking out TCR and CD52 genes using technologies like CRISPR/Cas9, thereby lowering graft-versus-host disease and host rejection risks (193). Such off-the-shelf products also enable large-scale manufacturing, with projected cost reductions exceeding 50%, and have already entered clinical trials for hematologic malignancies. Non-viral vector systems (e.g., Sleeping Beauty transposon or mRNA electroporation) avoid the complexity and potential risks associated with viral vectors while shortening the production cycle (194, 195). Automation has become fundamental to CAR-T cell manufacturing, streamlining processes, enhancing scalability, and mitigating challenges posed by skill shortages and high costs (196). Directly injecting LNP-mRNA or AAV (adeno-associated virus) formulations into patients to generate CAR-T cells in vivo also reduces associated costs like ex vivo manufacturing (197). Emerging preparation techniques include novel microfluidic chip systems that efficiently perform T-cell activation and gene transduction within a closed, highly controlled environment, demonstrating strong translational potential (83, 198–200).

6. Conclusion

Cellular senescence represents a core biological basis for the onset and progression of multiple age-related diseases. With advancing age, senescent cells accumulate within the body, not only directly impairing tissue regeneration and repair capabilities but also disrupting microenvironmental homeostasis through the secretion of a cascade of inflammatory factors (SASP), ultimately leading to organ dysfunction and disease progression. In recent years, CAR-T therapy, a technology originating from tumor immunotherapy, has emerged as a novel and promising strategy for intervening in aging-related diseases due to its ability to precisely identify and eliminate specific target cells. This article systematically explores the key molecular mechanisms of cellular senescence, including progressive telomere shortening, activation of critical pathways such as p53-p21 and p16-Rb, and the pathogenic effects of SASP. It reviews the design principles and developmental history of CAR-T technology, highlighting its application progress in aging-related tumors, neurodegenerative diseases, cardiovascular pathologies, and metabolic disorders based on the latest research findings. Research indicates that CAR-T cells can effectively eliminate pathologically aged cells by targeting surface markers such as uPAR, NKG2DLs, and FAP. Furthermore, by modulating the senescent state of T cells themselves, CAR-T therapy enhances their functional persistence and demonstrates significant therapeutic efficacy across multiple preclinical models.

However, the widespread application of CAR-T therapy for age-related diseases still faces numerous challenges. For example, elderly patients often suffer from immune senescence, leading to a decline in autologous T cell function. Therefore, strategies such as using allogeneic T cells, implementing anti-aging genetic engineering, and optimizing in vitro culture conditions are particularly important. Insufficient target specificity remains a major hurdle. Current solutions under exploration include developing dual-target CAR systems, designing CAR structures activated by microenvironmental conditions, and identifying novel targets with greater aging specificity. Regarding safety, controllable CARs (such as inducible CARs or those with built-in “suicide switches”), cytokine blockers, and personalized dosing regimens are under active investigation. Additionally, the traditional CAR-T preparation process is complex and costly, limiting its accessibility. Efforts to address this include developing universal CAR-T cells, utilizing non-viral vector technologies, and implementing automated manufacturing processes, which hold promise for expanding patient access.

Looking ahead, CAR-T therapy has yet to be applied to kidney aging-related diseases. However, as the pathogenic mechanisms of cellular senescence in chronic kidney disease, renal fibrosis, diabetic nephropathy, and other kidney aging-related conditions become increasingly clear, targeted clearance of senescent cells will emerge as a crucial strategy for intervening in the progression of these diseases. Leveraging their highly specific antigen recognition and cytotoxic capabilities, CAR-T cell therapies have demonstrated significant efficacy in organ aging models such as the liver and lung, laying a solid foundation for their application in renal diseases. In the future, with the continuous identification of kidney-specific senescence markers, CAR-T therapy holds promise for precisely eliminating senescent populations such as tubular epithelial cells and fibroblasts, blocking SASP-mediated inflammation and fibrosis processes, thereby delaying renal function decline.

Ultimately, through deepening our understanding of aging biology and continuous optimization of CAR-T technology, this approach may not only become a crucial tool for treating age-related diseases but also hold promise for extending human “healthy lifespan,” offering a powerful new weapon in the fight against aging.

Funding Statement

The author(s) declared that financial support was received for this work and/or its publication. This work was supported by the National Natural Science Foundation of China (Grant Nos. 82200769), Henan Province Science and Technology Research Project of 2024, Henan Provincial Health Commission (Nos. 242102310245).

Author contributions

XA: Software, Writing – original draft. TW: Data curation, Supervision, Writing – review & editing. RG: Data curation, Supervision, Writing – review & editing. YF: Conceptualization, Investigation, Methodology, Writing – review & editing.

Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declared that generative AI was not used in the creation of this manuscript.

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