Search Results (60)

Klotho is a longevity-associated and tissue-protective protein involved in mineral metabolism, oxidative stress, inflammation, fibrosis, cellular senescence, and neurovascular homeostasis. However, nearly three decades after its discovery, no Klotho-based therapy has been approved, highlighting a translational gap that extends beyond biological validation. This review reframes Klotho translation as a pharmaceutical sciences challenge, focusing on how to convert Klotho into a druggable, manufacturable, deliverable, and clinically controllable therapeutic product. We summarize the isoform-specific properties of membrane-bound α-Klotho, soluble α-Klotho, and β-Klotho that are relevant to product design, and review the current clinical and preclinical landscape dominated by gene-, mRNA-, and antibody-based approaches. We further distinguish confirmed developability barriers, including renal handling and limited systemic persistence, from plausible risks common to macromolecular biologics, such as aggregation, chemical degradation, immunogenicity, and poor tissue penetration. Finally, we evaluate emerging delivery and formulation strategies, including viral and non-viral gene delivery, extracellular vesicles, hydrogels, ultrasound-targeted microbubbles, osmotic pumps, and long-acting protein engineering. An integrated roadmap combining molecular engineering, disease-specific delivery, pharmacokinetic/pharmacodynamic biomarkers, manufacturability assessment, and repeated-dose safety evaluation may help transform Klotho from a promising anti-aging molecule into a clinically viable biologic platform. Full article

Background: Fibroblast growth factor 23 (FGF23) and α-Klotho are key regulators of mineral metabolism and bone homeostasis; however, their combined diagnostic value in postmenopausal osteoporosis remains incompletely understood. This study investigated the associations of serum FGF23, α-Klotho, and the FGF23/α-Klotho ratio with bone mineral density (BMD), bone turnover markers, and their diagnostic performance for postmenopausal osteoporosis. Methods: This cross-sectional study included 165 women divided into three groups: premenopausal healthy controls (n = 55), postmenopausal non-osteoporotic women (n = 55), and postmenopausal women with osteoporosis (n = 55). Serum FGF23 and α-Klotho concentrations were measured by enzyme-linked immunosorbent assay. Bone mineral density was assessed by dual-energy X-ray absorptiometry. Correlation analyses, age- and BMI-adjusted partial correlations, multivariable linear and logistic regression analyses, receiver operating characteristic (ROC) analyses, and incremental diagnostic models were performed. Diagnostic ROC and incremental model analyses were restricted to postmenopausal women (n = 110). Results: Serum FGF23 concentrations and the FGF23/α-Klotho ratio increased progressively across the study groups, whereas α-Klotho levels decreased (all p < 0.001). FGF23 was inversely correlated with lumbar spine, femoral neck, and total hip BMD and T-scores (all p < 0.001), whereas α-Klotho demonstrated positive correlations with all BMD parameters (all p < 0.001). These associations remained significant after adjustment for age and BMI. In multivariable linear regression analyses, the FGF23/α-Klotho ratio showed the strongest independent association with skeletal T-scores (standardized β = −0.379 to −0.404; all p < 0.001). Multivariable logistic regression identified lower 25-hydroxyvitamin D, higher parathyroid hormone, higher FGF23, and lower α-Klotho as independent factors associated with osteoporosis. In analyses restricted to postmenopausal women, the FGF23/α-Klotho ratio showed the highest numerical discriminative performance for osteoporosis (AUC = 0.832, 95% CI: 0.755–0.901), followed by α-Klotho (AUC = 0.793) and FGF23 (AUC = 0.697). The ratio significantly outperformed FGF23 alone (ΔAUC = 0.135, p = 0.001), whereas its performance did not differ significantly from that of α-Klotho (ΔAUC = 0.038, p = 0.270). Adding FGF23 and α-Klotho to age, BMI, and 25-hydroxyvitamin D increased the AUC from 0.743 to 0.882. Conclusions: Serum FGF23 and α-Klotho are independently associated with bone mineral density and are linked to bone turnover markers in postmenopausal women. The FGF23/α-Klotho ratio showed the highest numerical discriminative performance among the evaluated biomarkers, although its performance was not significantly different from that of α-Klotho alone. The combined assessment of FGF23 and α-Klotho provided additional discriminatory information beyond the measured clinical variables. Given the cross-sectional design and lack of external validation, these findings should be considered exploratory and require validation in prospective independent cohorts. Full article

Neuroinflammation plays a central role in Alzheimer’s disease (AD). Glycyrrhizin (GL), a major component of licorice, exhibits anti-inflammatory effects, but its effects on AD pathology remain unclear. To investigate the effects of GL (18β-glycyrrhizin, 18β-GL) and its stereoisomer (18α-glycyrrhizin, 18α-GL) on cognitive function, neuroinflammation, and AD pathology in senescence-accelerated mouse prone 8 (SAMP8; P8) mice, 40-week-old P8 male mice, an AD model due to aging, and the control (senescence-accelerated mouse resistant 1, SAMR1; R1) mice were treated with 18β-GL, 18α-GL and physiological saline (control) for 12 weeks (n = 6 in each group). Cognitive function was evaluated using a step-through passive avoidance test. Plasma levels of α-Klotho, IGF-1, 2′,3′-cyclic GMP-AMP (2′,3′-cGAMP), HMGB1, IL-6, and TNF-α were measured by ELISA. Hippocampal microglial activation (Iba1), amyloid-β (Aβ) deposition, and phosphorylated tau (p-Tau) were assessed by immunohistochemistry. Aged P8 mice showed impaired memory, decreased α-Klotho and IGF-1 levels, and increased inflammatory markers compared with R1 mice. GL significantly improved memory performance, reduced inflammatory markers, and suppressed Iba1 activation, as well as Aβ and p-Tau accumulation. These effects were associated with inhibition of the cGAS–STING pathway, as indicated by reduced 2′,3′-cGAMP and HMGB1 levels. GL ameliorates AD pathology by inhibiting neuroinflammation, suggesting its therapeutic potential for AD. Full article

Background and Purpose: Ultra-processed food (UPF) intake is a risk factor for metabolic dysfunction-associated steatotic liver disease (MASLD) development, and fibroblast growth factor 21 (FGF21) is a key regulator of hepatic lipid metabolism, but its role in this association remains unclear. We aimed to investigate whether FGF21 mediates the UPF-MASLD relationship in a population-based cohort and whether berry extract (BE) protects against UPF-related liver injury through FGF21 signaling. Methods: This study included 29,386 participants with magnetic resonance imaging (MRI)-derived proton density fat fraction (PDFF) and iron-corrected T1 (cT1) from the UK Biobank. UPF intake was classified according to the NOVA system. Log-binomial and generalized linear regression models were used to estimate the associations of UPF with MASLD, PDFF, and cT1, respectively. In vivo, nine-month-old male C57BL/6J mice were fed a baked Western diet (BWD) with bilberry extract (BE, 200 mg/kg/day) or vehicle for 16 weeks. In vitro, the role of FGF21 was examined by knockdown experiments in AML12 hepatocytes. Results: UPF consumption was linearly associated with a higher risk of MASLD, with per 10% increment associated with 9% higher risk of MASLD (RR 1.09 [95% CI 1.07–1.10]), as well as dose-dependent increases in PDFF and cT1. Among the 283 plasma proteins associated with PDFF, FGF21 showed the strongest association with UPF intake and accounted for the largest proportion of mediation in the UPF-PDFF association. A significant interaction between UPF and berry intake was observed in MASLD risk (p for interaction = 0.018). In the animal model, BE supplementation for 16 weeks alleviated BWD-induced hepatic steatosis, inflammation, and glucose intolerance, while upregulating hepatic FGF21, FGFR1c, and β-Klotho expression and improving mitochondrial function. FGF21 knockdown abrogated BE’s protective effect against lipid accumulation in vitro. Conclusions: FGF21 emerged as a potential mediator of the association between UPF consumption and liver fat accumulation. Anthocyanin-rich dietary interventions may offer a promising strategy to prevent MASLD progression. Full article

Sepsis is a life-threatening condition characterized by a dysregulated host response to infection, leading to multi-organ dysfunction. Toll-like receptor signaling via MYD88- and TRIF-dependent pathways plays a central role in this process; however, its temporal and tissue-specific dynamics remain incompletely understood. The aim of this study was to investigate time-dependent transcriptional changes in MYD88- and TRIF-dependent signaling pathways across multiple organs in a murine model of sepsis. mRNA expression of MYD88, IRAK1, IRAK4, NF-kB, CCL4, CCL20, CCR2, IFN-β, IFN-γ, TNF-α, IL-1β, IL-2, IL-4, IL-8, IL-10, IL-18, Klotho, KLF4, HOXA5, NANOG and HIF1α was quantified using qRT-PCR in intestinal, kidney, liver and lung tissues at 24, 48, and 72 h following cecal ligation and puncture-induced sepsis in male C57BL/6J mice. Significant upregulation of innate immune signaling molecules, cytokines, chemokines, and interferon-related genes was observed in all tissues compared with controls. Genes associated with hypoxia and cellular regulation were also increased. These responses were tissue-specific and progressively intensified over time. Sepsis represents a dynamic, time-dependent, and tissue-specific process characterized by sustained activation of immune and hypoxic pathways, providing potential targets for time-stratified therapeutic strategies. Full article

Background/Objectives: Vascular calcification and arterial stiffness are common in chronic kidney disease (CKD). Gla-rich protein (GRP) is a vitamin K-dependent protein implicated in mineral biology, but clinical evidence across CKD stages is limited. We evaluated associations of serum GRP with vascular calcification (VC) burden and arterial stiffness across CKD stages, including hemodialysis, compared with controls. Methods: In this prospective observational study, 185 adults were enrolled: controls (n = 61), individuals with CKD stage IIIb–IV (n = 61), and individuals with CKD stage V on hemodialysis (HD) (n = 63). Abdominal aortic calcification was assessed by the Kauppila score, and arterial stiffness was assessed by oscillometric pulse wave velocity (PWV). Serum GRP, FGF-23, and β-Klotho (KLb) were measured by ELISA. Non-parametric group comparisons and Bonferroni-corrected Spearman correlations were used. Results: GRP differed across groups (p < 0.001), showing a non-linear pattern with the lowest values in CKD IIIb–IV. PWV and Kauppila score increased across CKD stages (both p < 0.001). After Bonferroni correction, GRP correlated with KLb (ρ = 0.720) and FGF-23 (ρ = 0.625), but not with PWV or Kauppila score. In multivariable analyses, GRP showed a statistically significant but modest association with PWV and Kauppila score. Conclusions: In this CKD spectrum cohort, serum GRP was associated with CKD-MBD biochemical markers (KLb and FGF-23) much more strongly than with vascular phenotypes; its associations with vascular calcification burden and arterial stiffness were modest in multivariable modelling, supporting GRP as a marker of the CKD-MBD biochemical profile rather than a strong surrogate of vascular phenotype. Full article

Mice genetically deficient in α-Klotho (henceforth Klotho) display accelerated aging. The mechanisms are only partially understood. Here, we examine how these relate to the 12 hallmarks of aging consisting of chronic inflammation (inflammaging), as well as damaging changes to the genome (DNA damage), telomeres, epigenetic regulation, proteostasis, nutrient sensing, mitochondria, stem cells, intercellular communication, macroautophagy, microbiome and cell replication (senescence). Inflammation aggravates the other hallmarks. We report that Klotho counters the majority of these hallmarks. It ameliorates mitochondrial function and reduces reactive oxygen species (ROS), telomere attrition and cellular senescence. It protects against inflammation by inhibiting NF-κB and the NLRP3 inflammasome. This applies to inflammaging, several chronic inflammatory diseases, atherosclerosis, diabetes, and Alzheimer’s disease. Klotho also counters some aging factors outside of these hallmarks. Low Klotho (often due to kidney disease) produces hyperphosphatemia, which injures cells (especially endothelial cells) and promotes aging. Another key action of Klotho is the mitigation of fibrosis in major organs (kidneys, heart, lungs and other), mainly through the inhibition of TGF-β and Wnt. Klotho also protects against muscle atrophy (sarcopenia)—a common feature of aging—and exhibits anti-cancer activity. We describe several factors that increase Klotho, and are potentially amenable to clinical therapy. Full article

This pilot study aimed to investigate the role of the Klotho/FGF (fibroblast growth factor) system in biological features associated with premature aging, particularly inflammation and muscle dysfunction, focusing on its association with inflammatory markers, body composition, and muscle function in middle-aged adults. A total of 45 participants aged 50–60 years were enrolled, including 30 patients with obesity (22F/8M) and 15 healthy controls (11F/4M). Comprehensive assessments were conducted, including body composition analysis and muscle function tests. Evaluations of protein expression of Klotho, β-Klotho, FGF19, FGF21, FGF23, TFN-α and IL-10 were assessed in peripheral blood mononuclear cells (PBMCs). A Principal Component Analysis (PCA) was carried out to explore the relationships among variables. Significant differences were observed between the obese and control groups, with obese individuals exhibiting lower levels of Klotho and higher levels of TFN-α. The PCA revealed that higher Klotho levels were positively associated with better muscle function and lower inflammatory markers. These associations suggest that Klotho-related alterations may reflect biological processes linked to inflammation and muscle dysfunction in obesity. These findings suggest that alterations in the Klotho/FGF system may reflect biological pathways commonly associated with aging-related phenotypes in obesity, rather than direct measures of chronological aging. Given the exploratory design and limited sample size, these findings should be interpreted as hypothesis-generating rather than evidence of causal mechanisms. Full article

Background: Chronic kidney disease (CKD) markedly increases the risk of cardiovascular events (CVE), yet conventional biomarkers often fail to capture this excess risk. We evaluated whether circulating levels and genetic variability within the FGF19/β-Klotho/FGFR axis contribute to CV risk stratification in CKD. Methods: In 579 CKD patients, plasma FGF19 and β-Klotho concentrations were quantified, and 64 genetic variants across FGF19, KLB, FGFR1, and FGFR4 genes were analyzed. Results: Cluster analysis identified three distinct biomarker profiles, with one cluster—characterized by low/intermediate FGF19 and markedly elevated β-Klotho—showing significantly reduced CV event-free survival. After adjustment for clinical covariates, this cluster was independently associated with higher CV risk [HR = 2.97 (1.12–7.92), p = 0.029]. Two genetic variants also showed independent associations: FGFR1 rs2288696 (protective) [HR = 0.51 (0.27–0.95), p = 0.029] and KLB rs2687971 (risk-increasing) [HR = 2.03 (0.97–4.27), p = 0.046]. A combined CV risk model incorporating biomarker clusters, relevant SNPs, and traditional risk factors achieved good discriminative ability (C-index = 0.80), with the FGF19/β-Klotho cluster showing predictive importance comparable to diabetes and previous CV history. Conclusions: These results indicate that integrating FGF19-Klotho biomarkers with genetic information may improve CV risk prediction in CKD. Full article

The downregulation of Klotho in renal injury predicts the progression of chronic kidney disease (CKD). Klotho acts as an antagonist of the Wnt/β-catenin pathway, which is involved in the pathogenesis of proteinuria, glomerulosclerosis and tubulointerstitial fibrosis. We investigated whether losartan (L, angiotensin II type-1 receptor blocker) alone or combined with synthetic (tempol, T) or natural antioxidants (olive leaf extract, O) could alter Klotho/Wnt4/β-catenin signaling, thus reducing fibrosis and slowing the progression of focal segmental glomerulosclerosis (FSGS) in spontaneously hypertensive rats (SHR). The rats were divided into five groups. The control rats received a vehicle. The other groups received adriamycin (2 mg/kg, i.v., twice in a 3-week interval) for FSGS induction. Treatments with L, L+T and L+O (10, 10 + 100 and 10 + 80 mg/kg/day, respectively) were administered by gavage during six weeks. In the kidneys of model rats, Klotho and Wnt4 were downregulated, whereas β-catenin and fibronectin levels were increased compared with the control group. L+T did not alter Klotho, Wnt4 or fibronectin levels, while it further increased β-catenin. In contrast, L+O improved Klotho, and reduced β-catenin and fibronectin levels, although it increased PAI-1. The L+O combination reduced proteinuria more efficiently than L and decreased renal injury close to control levels. Although these findings indicate that combined treatment of losartan and olive leaf extract is promising in slowing the progression of the experimental FSGS, further clinical studies are needed to confirm its favorable outcomes and safety in CKD patients. Full article

Phosphate is emerging as an active mediator of oxidative stress and vascular injury in chronic kidney disease (CKD). This emerging pathophysiological framework, referred to as “Phosphatopathy”, describes the systemic syndrome driven by chronic phosphate overload and characterized by oxidative stress, inflammation, endothelial dysfunction, vascular calcification, cellular senescence, and metabolic imbalance. Beyond being a biochemical marker, phosphate overload triggers NOX-derived reactive oxygen species (ROS), activates Wnt/β-catenin and TGF-β signaling, and disrupts the FGF23–Klotho axis, promoting endothelial dysfunction, vascular calcification, and left ventricular hypertrophy (LVH). These pathways converge with systemic inflammation and energy imbalance, contributing to the malnutrition–inflammation–atherosclerosis (MIA) syndrome. Experimental and clinical data reveal that the phosphate/urinary urea nitrogen (P/UUN) ratio is a sensitive biomarker of inorganic phosphate load, while emerging regulators such as microRNA-125b and calciprotein particles integrate phosphate-driven oxidative and inflammatory responses. Therapeutic strategies targeting phosphate burden—rather than serum phosphate alone—include dietary restriction of inorganic phosphate, non-calcium binders, magnesium and zinc supplementation, and activation of important pathways related to the activation of antioxidant defense such as AMP-activated protein kinase (AMPK) and SIRT1. This integrative framework redefines phosphate as a modifiable upstream trigger of oxidative and metabolic stress in CKD. Controlling phosphate load and redox imbalance emerges as a convergent strategy to prevent vascular calcification, improve arterial stiffness, and reduce cardiovascular risk through personalized, mechanism-based interventions. Full article

Cardiometabolic diseases (CVDs) are the leading cause of premature mortality and disability worldwide, arising from of cardiovascular and metabolic dysregulation. This review focuses on six critical therapeutic targets established in cardiometabolic regulation: GLP-1R, GIPR, FGFR1/β-Klotho, PCSK9, NF-κB, and the NLRP3 inflammasome. Drawing on curated structural datasets, we analyze the mechanisms of action and map key binding domain features that govern ligand efficacy and specificity. Dual GLP-1R/GIPR agonists, such as tirzepatide, demonstrate superior outcomes in glycemic control and weight reduction. Concurrently, inhibiting PCSK9, NF-κB, and NLRP3 helps to lower cholesterol and reduce harmful inflammation, offering cardioprotection. Structural analysis across these targets reveals complementary motifs (aromatic, hydrophobic, and polar residues). These insights guide the rational design of next-generation multi-target ligands (molecules capable of modulating two or more biological targets involved in related disease pathways, producing integrated therapeutic effects). Such integrated agents are promising for providing combined cardiovascular and metabolic benefits, thus reducing the risks associated with complex therapeutic drug combinations. Full article

Aging is driven by interconnected genetic, metabolic, and environmental factors that manifest as hallmarks including genomic instability, telomere attrition, epigenetic drift, and altered intercellular signaling. The Klotho-FGF23 axis has emerged as a critical regulator linking mineral metabolism to systemic aging processes. Membrane-bound Klotho, primarily in the kidney and parathyroid, acts as an obligate co-receptor for FGF23 to regulate phosphate and vitamin D homeostasis, while soluble Klotho exerts hormone-like effects that modulate Wnt, IGF-1, NF-κB, and TGF-β pathways, influencing oxidative stress, inflammation, and tissue regeneration. Deficiency of Klotho or FGF23 in animal models results in hyperphosphatemia, vascular calcification, and premature aging phenotypes, whereas Klotho overexpression or supplementation extends lifespan and enhances stress resilience. Beyond its renal role, FGF23 can activate Klotho-independent FGFR4 signaling in cardiomyocytes, promoting hypertrophy and contributing to cardiovascular risk. This review integrates current mechanistic insights on Klotho-FGF23 signaling within the framework of aging hallmarks, differentiating protective Klotho-dependent pathways from maladaptive Klotho-independent effects. We evaluate therapeutic strategies including recombinant Klotho protein, gene therapy, dietary phosphate restriction, FGFR4 inhibition, and senolytics approaches that restore Klotho expression. Key translational challenges remain assay variability and poor standardization of soluble Klotho measurement, limited longitudinal human data, and differences between murine models and human aging. Addressing these barriers will be essential to advancing Klotho-FGF23 targeted interventions as a viable strategy to extend health span and delay age-related pathologies. Full article

According to the World Health Organization (WHO), a healthy lifestyle is defined as a way of living that lowers the risk of becoming seriously ill or dying prematurely. Physical activity, as a well-known contributor to overall health, plays a vital role in supporting such a lifestyle. Exercise induces complex molecular responses that mediate both acute metabolic stress and long-term physiological adaptations. FGF21 (fibroblast growth factor 21) and GDF15 (growth differentiation factor 15) are recognized as metabolic stress markers, while their receptors play critical roles in cellular signaling. However, the differential gene expression patterns of these molecules in trained and untrained individuals following exhaustive exercise remain poorly understood. This study aimed to examine the transcriptional and protein-level responses in trained and untrained individuals performed a treadmill maximal exercise test to voluntary exhaustion. Blood samples were collected at six time points (pre-exercise, immediately post-exercise, and 0.5 h, 6 h, 24 h, and 48 h post-exercise). Gene expression of FGF21, GDF15, FGFR1 (fibroblast growth factor receptors), FGFR3, FGFR4, KLB (β-klotho), and GFRAL (glial cell line-derived neurotrophic factor receptor alpha-like) was analyzed using RT-qPCR, while plasma protein levels of FGF21 and GDF15 were quantified via ELISA. The results obtained were statistically analyzed by using Shapiro–Wilk, Mann–Whitney U, and Wilcoxon tests in Statistica 13 software. Untrained individuals demonstrated significant post-exercise upregulation of FGFR3, FGFR4, KLB, and GFRAL. FGF21 and GDF15 protein levels were consistently lower in trained individuals (p < 0.01), with no significant correlations between gene and protein expression. Trained individuals showed more stable expression of genes, while untrained individuals exhibited transient upregulation of genes after exercise. Full article

Background/Objectives: Chronic kidney disease–mineral and bone disorder (CKD-MBD) and systemic inflammation contribute to mortality in hemodialysis (HD) patients. The primary aim of this study was to determine whether specific CKD-MBD markers and inflammatory biomarkers are associated with increased mortality risk in HD patients. Methods: We conducted a retrospective cohort study on 63 stage 5D CKD patients undergoing maintenance HD. Serum intact parathyroid hormone (iPTH), soluble Klotho, calcium, phosphorus, 25(OH)D (25-hydroxyvitamin D), transforming growth factor-beta (TGF-β), vascular endothelial growth factor (VEGF), C-reactive protein (CRP), and interleukin-6 (IL-6) were analyzed. A Cox regression analysis assessed mortality predictors, and linear regression analysis evaluated CKD-MBD–inflammation correlations. Results: Lower iPTH (<329.3 pg/mL) levels were the only significant mortality predictor (p = 0.042). Other CKD-MBD markers (calcium, phosphorus, 25(OH)D, VEGF, TGF-β) did not impact survival. Soluble Klotho correlated positively with IL-6 (r = 0.57, p < 0.001), suggesting a compensatory inflammatory response. Conclusions: Our findings demonstrate that low iPTH levels and advanced age are independent predictors of mortality in hemodialysis patients. The positive association between soluble Klotho and IL-6 suggests a potential compensatory inflammatory response. These results highlight the need for further research to clarify underlying mechanisms and to explore novel therapeutic strategies. Full article