Klotho, Aging, and the Failing Kidney

Systemic immunoinflammatory indexes in albuminuric adults are negatively associated with α-klotho: evidence from NHANES 2007-2016

BACKGROUND

Systemic Immune-Inflammation Index (SII) is a novel inflammatory biomarker closely associated with the inflammatory response and chronic kidney disease. Klotho is implicated as a pathogenic factor in the progression of kidney disease, and supplementation of Klotho may delay the progression of chronic kidney disease by inhibiting the inflammatory response. Our aim is to investigate the potential relationship between SII and Klotho in adult patients in the United States and explore the differences in the populations with and without albuminuria.

METHODS

We conducted a cross-sectional study recruiting adult participants with complete data on SII, Klotho, and urine albumin-to-creatinine ratio (ACR) from the National Health and Nutrition Examination Survey from 2007 to 2016. SII was calculated as platelet count × neutrophil count/lymphocyte count, with abnormal elevation defined as values exceeding 330 × 10^9/L. Albuminuria was defined as ACR >30 mg/g. Weighted multivariable regression analysis and subgroup analysis were employed to explore the independent relationship between SII and Klotho.

RESULTS

Our study included a total of 10,592 individuals. In all populations, non-albuminuria population, and proteinuria population with ACR ≥ 30, participants with abnormally elevated SII levels, as compared to those with SII less than 330 × 10^9/L, showed a negative correlation between elevated SII levels and increased Klotho, which persisted after adjusting for covariates.

CONCLUSIONS

There is a negative correlation between SII and Klotho in adult patients in the United States. This finding complements previous research but requires further analysis through large prospective studies.

Sex-dependent changes in AMPAR expression and Na, K-ATPase activity in the cerebellum and hippocampus of α-Klotho-Hypomorphic mice

Aging is characterized by a functional decline in several physiological systems. α-Klotho-hypomorphic mice (Kl-/-) exhibit accelerated aging and cognitive decline. We evaluated whether male and female α-Klotho-hypomorphic mice show changes in the expression of synaptic proteins, N-methyl-d-aspartate receptor (NMDAR) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunits, postsynaptic density protein 95 (PSD-95), synaptophysin and synapsin, and the activity of Na+, K+-ATPase (NaK) isoforms in the cerebellum and hippocampus. In this study, we demonstrated that in the cerebellum, Kl-/- male mice have reduced expression of GluA1 (AMPA) compared to wild-type (Kl+/+) males and Kl-/- females. Also, Kl-/- male and female mice show reduced ɑ2/ɑ3-NaK and Mg2+-ATPase activities in the cerebellum, respectively, and sex-based differences in NaK and Mg2+-ATPase activities in both the regions. Our findings suggest that α-Klotho could influence the expression of AMPAR and the activity of NaK isoforms in the cerebellum in a sex-dependent manner, and these changes may contribute, in part, to cognitive decline.

Deciphering the Biological Aging Impact on Alveolar Bone Loss: Insights From α-Klotho and Renal Function Dynamics

Alveolar bone loss is generally considered a chronological age-related disease. As biological aging process is not absolutely determined by increasing age, whether alveolar bone loss is associated with increasing chronological age or biological aging remains unclear. Accurately distinguishing whether alveolar bone loss is chronological age-related or biological aging-related is critical for selecting appropriate clinical treatments. This study aimed to identify the relationship between alveolar bone loss and body aging. In total, 3 635 participants from the National Health and Nutrition Examination Survey and 71 living kidney transplant recipients from Gene Expression Omnibus Datasets were enrolled. Multivariate regression analysis, smooth curve fittings, and generalized additive models were used to explore the association among alveolar bone loss, age, serum α-Klotho level, renal function markers, as well as between preoperative creatinine and renal cortex-related α-Klotho gene expression level. Meanwhile, a 2-sample Mendelian randomization (MR) study was conducted to assess the causal relationship between α-Klotho and periodontal disease (4 376 individuals vs 361 194 individuals). As a biological aging-related indicator, the α-Klotho level was negatively correlated with impaired renal function and alveolar bone loss. Correspondingly, accompanied by decreasing renal function, it was manifested with a downregulated expression level of α-Klotho in the renal cortex and aggravated alveolar bone loss. The MR analysis further identified the negative association between higher genetically predicted α-Klotho concentrations with alveolar bone loss susceptibility using the IVW (odds ratio [OR] = 0.999, p = .005). However, an inversely U-shaped association was observed between chronological age and alveolar bone loss, which is especially stable in men (the optimal cutoff values were both 62 years old). For men above 62 years old, increasing age is converted to protective factor and is accompanied by alleviated alveolar bone loss. Alveolar bone loss that is directly associated with decreased renal function and α-Klotho level was related to biological aging rather than chronological age. The renal-alveolar bone axis could provide a new sight of clinical therapy in alveolar bone loss.

Polystyrene microplastics facilitate renal fibrosis through accelerating tubular epithelial cell senescence

Microplastics (MPs), emerging contaminants, are easily transported and enriched in the kidney, suggesting the kidney is susceptible to the toxicity of MPs. In this study, we explored the toxicity of MPs, including unmodified polystyrene (PS), negative-charged PS-SO3H, and positive-charged PS-NH2 MPs, in mice models for 28 days at a human equivalent concentration. The results showed MPs significantly increased levels of UREA, urea nitrogen (BUN), creatinine (CREA), and uric acid (UA) levels in serum and white blood cells, protein, and microalbumin in urine. In the kidney, MPs triggered persistent inflammation and renal fibrosis, which was caused by the increased senescence of tubular epithelial cells. Moreover, we identified the critical role of the Klotho/Wnt/β-catenin signaling pathway in the process of MPs induced senescence of tubular epithelial cells, promoting the epithelial-mesenchymal transformation of epithelial cells. MPs supported the secretion of TGF-β1 by senescent epithelial cells and induced the activation of renal fibroblasts. On the contrary, restoring the function of Klotho can alleviate the senescence of epithelial cells and reverse the activation of fibroblasts. Thus, our study revealed new evidence between MPs and renal fibrosis, and adds an important piece to the whole picture of the plastic pollution on people's health.

The association of platelet count, high-density lipoprotein cholesterol, and platelet/high-density lipoprotein cholesterol ratio with serum soluble Klotho

BACKGROUND AND OBJECTIVE

Klotho is a protein that is closely related to human aging. Soluble Klotho (S-Klotho) is a circulating protein, and its level decreases in response to systemic inflammation. The relationship between the platelet/high-density lipoprotein cholesterol ratio (PHR), an emerging inflammatory index, and S-Klotho concentrations is still unclear. In addition, the mean platelet volume has been confirmed to have a significant negative association with S-Klotho concentrations, but the relationship between the platelet count (PC) and S-Klotho concentrations has not yet been reported.

METHODS

Data from individuals who participated in the National Health and Nutrition Examination Survey (NHANES) during the five cycles from 2007 to 2016 were retrieved for analysis. Linear regression, two-piecewise linear regression, and restricted cubic spline (RCS) methods were used to analyze the associations of the PHR index and its components with S-Klotho concentrations. In addition, subgroup analysis and effect modification tests were conducted.

RESULTS

A total of 11,123 participants (5463 men (48.17%)), with an average age of 56.2 years, were included. After full adjustment, the S-Klotho levels of participants in the highest quartile group of PHR (β: -51.19, 95% CI: -75.41 to -26.97, P < 0.001) and the highest quartile group of PC (β: -72.34, 95% CI: -93.32 to -51.37, P < 0.0001) were significantly lower than those in their respective lowest quartile groups, and a significant downward trend was presented among the four groups (P for trend < 0.05, respectively). However, high-density lipoprotein cholesterol (HDL-C) concentrations were not significantly associated with S-Klotho concentrations. RCS revealed that the PHR and PC were nonlinearly associated with S-Klotho concentrations; two-piecewise linear regression revealed that the inflection points were 175.269 and 152, respectively, and that these associations slightly weakened after the inflection point. According to the subgroup analysis, liver disease status enhanced the association between the PC and S-Klotho concentrations.

CONCLUSIONS

Both the PHR and PC were significantly negatively associated with S-Klotho concentrations, and these associations were nonlinear. There was no significant association between HDL-C and S-Klotho concentrations. Liver disease status enhances the negative association between the PC and S-Klotho concentrations, and the specific mechanism deserves further exploration.

Role of advanced glycation end-products in age-associated kidney dysfunction in naturally aging mice

AIMS

Advanced glycation end-products (AGEs) are implicated in the age-related decline of renal function, exacerbated by conditions, such as hyperglycemia and oxidative stress. The accumulation of AGEs in the kidneys contributes to the progressive decline in renal function observed with aging. However, the precise role and mechanisms of AGEs in the age-related decline of renal function remain unclear. In this study, we investigated the impact and potential mechanisms of AGEs on aging kidneys in naturally aging mice.

MATERIALS AND METHODS

Male C57BL/6 mice were divided into three groups: 6-, 57-, and 107-week-old. First, the 6- and 107-week-old mice were euthanized. The remaining mice were divided into young (6 weeks) and old (57 weeks) groups. The 57-week-old mice were orally administered aminoguanidine (100 mg/kg/day), an AGEs inhibitor, or vehicle for 13 weeks, resulting in a final age of 70 weeks. The serum and kidney tissues were collected for biochemical measurement, histological examination, immunohistochemistry staining, and immunoblotting analysis.

KEY FINDINGS

Our findings revealed a notable accumulation of AGEs in both serum and kidney tissue specimens and renal dysfunction in naturally aging mice. Aminoguanidine not only reversed AGEs accumulation but also ameliorated renal dysfunction. Additionally, aminoguanidine attenuated the upregulation of fibrosis markers (phosphorylated p38/α-SMA and C/EBP homologous protein, CHOP), senescence markers (p53 and p21), and oxidative stress marker (4-HNE) in the aging kidneys.

SIGNIFICANCE

These findings underscore the critical role of AGEs in age-related renal dysfunction and highlight the therapeutic potential of aminoguanidine in mitigating fibrosis and senescence, offering prospective avenues for combating age-associated renal ailments.

Triiodothyronine enhances various forms of kidney-specific Klotho protein and suppresses the Wnt/β-catenin pathway: Insights from in-vitro, in-vivo and in-silico investigations

Age-related diseases are intricately linked to the molecular processes underlying aging, with the decline of the antiaging protein Klotho being a key factor. Investigating these processes is crucial for developing therapeutic strategies. The age-associated reduction in Klotho expression, coupled with a decline in the endocrine hormone triiodothyronine (T3), prompted a detailed exploration of their potential interplay. Our research, conducted through both in-vitro and in-vivo studies on BALB/c mice, unveiled a significant capacity of T3 to upregulate various forms of Klotho via ATF-3/p-c-Jun transcription factor. This effect was particularly noteworthy in aged individuals, where Klotho expression had waned compared to their younger counterparts. Importantly, T3 demonstrated a promising therapeutic impact in rejuvenating Klotho expression in this context. Further investigations elucidated the molecular mechanisms underlying T3's impact on aging-related pathways. In-vitro and in-vivo experiments established T3's ability to downregulate the Wnt/β-Catenin pathway by enhancing Klotho expression. In-silico analyses provided insights into Klotho's intricate role, showing its capacity to inhibit Wnt ligands such as Wnt3 and Wnt8a, consequently disrupting their interaction with the Wnt receptor. Additionally, T3 was found to downregulate kidney-specific GSK-3β expression through the augmentation of Klotho expression. The study also highlighted T3's role in maintaining calcium and phosphate homeostasis via Klotho. This comprehensive investigation not only sheds light on the intricate mechanisms governing aging processes but also presents promising avenues for therapeutic interventions targeting the Wnt/β-Catenin pathway implicated in various age-associated diseases.

Determination of the reference interval for urinary klotho to creatinine ratio of healthy dogs

For several years, alpha klotho has been considered as a candidate biomarker in chronic kidney disease (CKD), progression of CKD and CKD mineral bone disorders (CKD-MBD). The evidence on the relationship between klotho and kidney function is controversial in some areas. The aim of the study was to identify the influence of age, sex and breed on urinary alpha klotho, values in the early stages of CKD within the studied population and determine a reference interval in a group of healthy dogs. Significantly higher values were measured in older dogs over 6 years old (p = 0.026, p = 0.0007) and in the breed German Shepherd than Belgian Shepherd (p = 0.0401). On the basis of sex and in small breed dogs, no significant differences were noted. In dogs with CKD stage 2, alpha klotho values were significantly lower (p = 0.0135) than in healthy dogs. Within the studied population, a reference interval for urinary klotho to creatinine ratio (UrKl/Cr) was determined in the range of 3.94-23.55 pg/gCr. Since our findings show that alpha klotho is associated with older age, we assume that this may have influenced the results in the group of dogs with CKD stage 1 due to the presence of predominantly old dogs in this group. Future studies would be needed to consider age as a factor affecting urinary alpha klotho in dogs with CKD.

Association between α-klotho levels and adults with COPD in the United States

Purpose

Chronic obstructive pulmonary disease (COPD) is accompanied by increased inflammation, persistent lung function decline, and extensive lung injury. Klotho, a well-known antiaging protein, has anti-inflammatory and antioxidative effects. However, the effects of klotho on COPD have yet to be thoroughly elucidated. This study examined the association among COPD adults and their α-klotho level.

Patients and methods

Data were collected from the 2007 to 2012 National Health and Nutrition Examination Survey (NHANES). A total of 676 participants were analyzed and divided into COPD (n = 403) and non-COPD (n = 273) groups. The two groups were compared with respect to clinical characteristics. Logistic regression analysis and a generalized additive model were used to estimate the association between COPD incidence and serum α-klotho concentration. All COPD participants were stratified according to the levels of α-klotho (Q1: <687 pg./mL; Q2: 687-900 pg./mL; Q3: ≥900 pg./mL), and clinical characteristics were compared.

Results

Non-COPD individuals had higher α-klotho levels than did COPD individuals (863.09 ± 267.13 vs. 817.51 ± 302.20, p < 0.05). Logistic regression analysis revealed that the Q2 and Q3 layers had a lower risk of COPD than did the Q1 layer, with odds ratios (ORs) of 0.73 (0.50, 0.99) for Q2 and 0.58 (0.41, 0.86) for Q3 (p < 0.001). The generalized additive model showed that the risk of COPD gradually decreased with increasing α-klotho concentration when the α-klotho concentration < 1,500 pg./mL, while the risk of COPD increased as the α-klotho concentration increased to ≥1,500 pg./mL. Compared with individuals in the Q2 or Q3 groups, individuals with COPD in the Q1 group were more likely to be current smokers, have lower levels of erythrocytes, and have higher levels of creatinine and leukocytes.

Conclusion

Increased α-klotho levels were negatively correlated with the risk of COPD in participants over 40 years old with α-klotho <1,500 pg./mL. When α-klotho was ≥1,500 pg./mL, the risk of COPD increased as α-klotho levels increased. Pulmonary ventilation function and the number of hemocytes differed among COPD patients with different levels of α-klotho.

Biomarkers of chronic kidney disease in older individuals: navigating complexity in diagnosis

Chronic kidney disease (CKD) in older individuals is a matter of growing concern in the field of public health across the globe. Indeed, prevalence of kidney function impairment increases with advancing age and is often exacerbated by age-induced modifications of kidney function, presence of chronic diseases such as diabetes, hypertension, and cardiovascular disorders, and increased burden related to frailty, cognitive impairment and sarcopenia. Accurate assessment of CKD in older individuals is crucial for timely intervention and management and relies heavily on biomarkers for disease diagnosis and monitoring. However, the interpretation of these biomarkers in older patients may be complex due to interplays between CKD, aging, chronic diseases and geriatric syndromes. Biomarkers such as serum creatinine, estimated glomerular filtration rate (eGFR), and albuminuria can be significantly altered by systemic inflammation, metabolic changes, and medication use commonly seen in this population. To overcome the limitations of traditional biomarkers, several innovative proteins have been investigated as potential, in this review we aimed at consolidating the existing data concerning the geriatric aspects of CKD, describing the challenges and considerations in using traditional and innovative biomarkers to assess CKD in older patients, highlighting the need for integration of the clinical context to improve biomarkers' accuracy.

Dietary folate intake and serum klotho levels in adults aged 40-79 years: a cross-sectional study from the national health and nutrition examination survey 2007-2016

Objective

This study aims to explore the relationship between dietary folate intake and serum Klotho levels in adults from aged 40 to 79 years in the United States, seeking to elucidate the intricacies of their interaction.

Methods

Analyzing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2016. The survey research determined folate intake through a 24-h dietary recall and nutrient density modeling, and assessed Klotho levels using enzyme-linked immunosorbent assay (ELISA). The relationship between folate intake and Klotho levels was evaluated using weighted linear regression, and complemented by analysis via smoothed curve models for nuanced understanding.

Results

The study encompassed 10,278 participants, with an average age of 57.64 years, revealing a noteworthy positive correlation between dietary folate and serum Klotho levels. The regression coefficient stood at 0.11 (95% confidence interval, 0.05, 0.18) post-adjustment for various covariates. When dietary folate intake was categorized into quartiles, the second, third, and fourth quartiles exhibited statistically significant differences compared to the lowest quartile. This indicates that higher folate intake correlates with increased serum Klotho levels. These findings underscore the potential benefits of elevating folate intake to enhance serum Klotho levels. Stratified analysis indicated that this association was more pronounced among males aged 60 years or older and individuals with hypertension.

Conclusion

The findings suggest a significant correlation between increased dietary folate intake and elevated serum Klotho levels in adults aged 40-79 years. Hinting at the potential nutritional influences on the aging process and associated health conditions. This calls for further exploration into the mechanisms and broader implications of this association.

From premature birth to premature kidney disease: does accelerated aging play a role?

As the limits of fetal viability have increased over the past 30 years, there has been a growing body of evidence supporting the idea that chronic disease should be taken into greater consideration in addition to survival after preterm birth. Accumulating evidence also suggests there is early onset of biologic aging after preterm birth. Similarly, chronic kidney disease (CKD) is also associated with a phenotype of advanced biologic age which exceeds chronologic age. Yet, significant knowledge gaps remain regarding the link between premature biologic age after preterm birth and kidney disease. This review summarizes the four broad pillars of aging, the evidence of premature aging following preterm birth, and in the setting of CKD. The aim is to provide additional plausible biologic mechanisms to explore the link between preterm birth and CKD. There is a need for more research to further elucidate the biologic mechanisms of the premature aging paradigm and kidney disease after preterm birth. Given the emerging research on therapies for premature aging, this paradigm could create pathways for prevention of advanced CKD.

Decreased cobalamin sensitivity and biological aging acceleration in the general population

BACKGROUND

The evidence on the association between cobalamin (Cbl) and aging or relevant outcomes is limited and controversial. We aimed to investigate the relationships between cobalamin intake- and function-related biomarkers and biological aging.

METHODS

The study encompassed 22,812 participants aged 20 years and older from the National Health and Nutrition Examination Survey. A panel of biomarkers or algorithms was used to assess biological aging, including Klemera-Doubal Age Acceleration (KDMAccel), Phenotypic age acceleration (PhenoAgeAccel), telomere length, α-Klotho, and PhenoAge advancement. Weighted generalized linear regression analysis was used to assess the associations between cobalamin-intake biomarkers (serum cobalamin, cobalamin intake from food, cobalamin supplement use, serum methylmalonic acid [MMA], and homocysteine [Hcy]) and function-related biomarkers (functional cobalamin deficiency and cobalamin insensitivity index).

RESULTS

Among the 22,812 individuals, the weighted mean (SE) age was 48.3 (0.2) years and 48.0% were males. Unexpectedly, serum and dietary cobalamin as well as serum MMA and Hcy levels were positively associated with most indicators of biological aging. Cobalamin sensitivity was assessed by the combination of binary Cbllow/high and MMAlow/high or Hcylow/high (cutoff values: 400 pg/mL for cobalamin, 250 nmol/L for MMA, and 12.1 μmol/l for Hcy) and a newly constructed cobalamin insensitivity index (based on the multiplicative term of serum cobalamin and serum MMA or Hcy). The multivariable-adjusted β (95%CIs) of KDMAccel in the MMAlowCbllow, MMAlowCblhigh, MMAhighCbllow, and MMAhighCblhigh groups were reference, 0.27 (0.03 to 0.51), 0.85 (0.41 to 1.29), and 7.97 years (5.77 to 10.17) respectively, which were consistent for the combination of serum Hcy and cobalamin. Both cobalamin insensitivity indices were robustly associated with biological aging acceleration in a dose-response pattern (each p < 0.001).

CONCLUSIONS

Decreased cobalamin sensitivity but not cobalamin insufficiency might be associated with biological aging acceleration. Further studies would improve understanding of the underlying mechanisms between decreased cobalamin sensitivity and biological aging acceleration.

Elevated Serum Copper, Zinc, Selenium, and Lowered α-Klotho Associations: Findings from NHANES 2011-2016 Dataset

The α-Klotho is crucial for human health and longevity. However, the relationship between trace elements and α-Klotho levels needs further investigation. We aimed to explore the relationship between serum levels of selenium (Se), copper (Cu), and zinc (Zn), and serum α-Klotho levels. We analyzed 2138 samples from the 2011-2016 National Health and Nutrition Examination Survey, and the weighted linear regression, WQS, and qgcomp models were utilized to evaluate the effects of these elements on serum α-Klotho levels, individually and combined. A negative correlation was observed between serum Cu concentration and serum α-Klotho levels (β =  - 0.128, 95% CI - 0.196, - 0.059), with each increase in Cu concentration grade showing a gradual decrease in serum α-Klotho levels (Ptrend = 0.002). The WQS model exhibited a negative correlation between the combined effect of Se, Cu, and Zn and serum α-Klotho levels (β =  - 0.035, 95%CI - 0.060, - 0.010), consistently in males (β =  - 0.038 (- 0.059, - 0.017)) and in the 40-49 age group (β =  - 0.059, 95% CI - 0.119, - 0.012). The qgcomp model mirrored these findings, showing a negative correlation in the combined effect index of Se, Cu, and Zn with serum α-Klotho levels (β =  - 0.027, 95% CI - 0.047, - 0.006), consistent in females (β =  - 0.032, 95% CI - 0.061, - 0.004) and in individuals with BMI ≥ 25 (β =  - 0.030, 95% CI - 0.054, - 0.006), and in the 40-49 age group (β =  - 0.047, 95% CI - 0.088, - 0.006). Elevated serum Cu levels may be associated with lower serum α-Klotho levels. The combined effect of serum Se, Cu, and Zn shows a negative correlation with serum α-Klotho levels, with Cu contributing the most. Our findings provide significant insights into assessing the role of trace nutrients in maintaining human health.

Towards Healthy Longevity: Comprehensive Insights from Molecular Targets and Biomarkers to Biological Clocks

Aging is a complex and time-dependent decline in physiological function that affects most organisms, leading to increased risk of age-related diseases. Investigating the molecular underpinnings of aging is crucial to identify geroprotectors, precisely quantify biological age, and propose healthy longevity approaches. This review explores pathways that are currently being investigated as intervention targets and aging biomarkers spanning molecular, cellular, and systemic dimensions. Interventions that target these hallmarks may ameliorate the aging process, with some progressing to clinical trials. Biomarkers of these hallmarks are used to estimate biological aging and risk of aging-associated disease. Utilizing aging biomarkers, biological aging clocks can be constructed that predict a state of abnormal aging, age-related diseases, and increased mortality. Biological age estimation can therefore provide the basis for a fine-grained risk stratification by predicting all-cause mortality well ahead of the onset of specific diseases, thus offering a window for intervention. Yet, despite technological advancements, challenges persist due to individual variability and the dynamic nature of these biomarkers. Addressing this requires longitudinal studies for robust biomarker identification. Overall, utilizing the hallmarks of aging to discover new drug targets and develop new biomarkers opens new frontiers in medicine. Prospects involve multi-omics integration, machine learning, and personalized approaches for targeted interventions, promising a healthier aging population.

The interaction between klotho protein and epigenetic alteration in diabetes and treatment options

Introduction

Klotho is a membrane protein predominantly expressed in the kidneys, and its discovery was serendipitously made through gene-targeting experiments conducted on mice. Klotho has a favorable role in the regulation of multiple cellular processes, such as aging, oxidative stress, inflammation, and apoptosis. This regulation occurs through the targeting of diverse signaling molecules, cell membrane receptors, and ion channels, achieved by physical contacts or enzymatic activities of Klotho. This review examines the role of Klotho in the epigenetic regulation of molecules associated with diabetes.

Methods

Authors conducted a thorough literature search using the PubMed®, Web of Science™, and Scopus®. Relevant articles up to September 2023, published in the English language were considered. We reviewed research databases searching for studies that included keywords klotho, epigenetic, and diabetes.

Results

14 related papers about epigenetic modification of proteins involved in diabetes pathogenesis were selected to be included in this narrative review. In the studies, the kidney was the most investigated organ regarding this correlation. Also, phosphorylation and methylation were the common epigenetic modifications of proteins by Klotho.

Conclusion

Klotho has a significant role in the maturation of adipocytes and the regulation of systemic glucose metabolism, exhibiting a strong association with the pathogenesis of diabetes. Both epigenetic alterations and the modulation of protein phosphorylation by Klotho play significant roles in the regulation of Klotho expression and the modulation of other molecules implicated in the etiology of diabetes.

GDF15, an Emerging Player in Renal Physiology and Pathophysiology

These last years, the growth factor GDF15 has emerged as a key element in many different biological processes. It has been established as being produced in response to many pathological states and is now referred to as a stress-related hormone. Regarding kidney functions, GDF15 has been involved in different pathologies such as chronic kidney disease, diabetic nephropathy, renal cancer, and so on. Interestingly, recent studies also revealed a role of GDF15 in the renal homeostatic mechanisms allowing to maintain constant, as far as possible, the plasma parameters such as pH and K+ values. In this review, we recapitulate the role of GDF15 in physiological and pathological context by focusing our interest on its renal effect.

Inverse association of the systemic immune-inflammation index with serum anti-ageing protein Klotho levels in individuals with osteoarthritis: A cross-sectional study

BACKGROUND

The association between the systemic immune-inflammation index (SII) and the serum soluble-Klotho concentration (pg/ml) in osteoarthritis (OA) patients is unknown. This study aimed to investigate the relationship between the SII and serum soluble-Klotho levels in OA patients.

METHODS

All study data were obtained from the National Health and Nutrition Examination Survey (NHANES) database (n = 1852 OA patients; age range = 40-79 years). The SII and serum Klotho measurement data are from the NHANES mobile examination centre. The SII values were divided into quartiles (Q1-4: 0.02-3.36, 3.36-4.78, 4.79-6.70, and 6.70-41.75). A multivariate linear regression model was constructed to evaluate the association between the SII and serum Klotho levels in OA patients; interaction tests were conducted to test the stability of the statistical results.

RESULTS

Multivariate linear regression revealed a negative linear relationship between the SII and serum Klotho concentration in OA patients (β = -6.05; 95% CI: -9.72, -2.39). Compared to Q1, Q4 was associated with lower serum Klotho concentrations (β = -59.93; 95% CI: -96.57, -23.28). Compared with that of Q1, the β value of Q2-Q4 showed a downwards trend as the SII increased (Ptrend <0.001). The stratified analysis results indicated that the SII had a greater sensitivity in predicting serum Klotho concentrations in OA patients aged 60-79 years (Pinteraction = 0.028).

CONCLUSIONS

There was a significant negative linear correlation between the SII and serum Klotho concentration in OA patients. The SII can serve as a predictive indicator of serum Klotho concentrations in OA patients. Klotho may be a potential anti-inflammatory drug for OA treatment.

Non-neurological factors associated with serum neurofilament levels in the United States population

OBJECTIVE

To model interdependencies of serum neurofilament light chain (sNfL), a clinically useful biomarker of axonal injury in neurological diseases, with demographic, anthropometric, physiological, and disease biomarkers in the United States population.

METHODS

sNfL and 80 biomarkers were obtained from the National Health and Nutrition Examination Survey (n = 2071, age: 20-75 years). Body habitus and composition, electrolytes, blood cell, metabolic, liver, and kidney function biomarkers, and common diseases were assessed with weighted regression adjusted for age, sex, and race/ethnicity. Salient biomarkers were modeled with ensemble learning; a Bayesian network structure was obtained for interdependencies.

RESULTS

Age was strongly associated with sNfL. sNfL levels were 13% higher in men versus women. Mexican Americans had 18.5% lower sNfL versus Non-Hispanic Whites. sNfL was similar in pregnant versus nonpregnant women. Lymphocyte, and neutrophil numbers, and phosphorus, and chloride levels were associated with sNfL. Multiple liver function (e.g., albumin and gamma-glutamyltransferase), renal function (e.g., creatinine and urea), and carbohydrate/lipid metabolism markers (e.g., glucose and triglycerides) were associated with sNfL. A 50% greater creatinine was associated with 26.8% greater sNfL. Diabetes, kidney disease, congestive heart failure, and stroke were associated with sNfL. The ensemble learning algorithm predicted high sNfL outliers with 5.06%-9.16% test error. Bayesian network modeling indicated sNfL had neighbor dependencies with age, creatinine, albumin, and chloride.

INTERPRETATION

sNfL is associated with age, kidney and liver function, diabetes, blood cell subsets, and electrolytes. sNfL may be a useful biomarker for biological age of the whole body and major organ systems including the brain.

The Effect of Propofol on the Hippocampus in Chronic Cerebral Hypoxia in a Rat Model Through Klotho Regulation

BACKGROUND/AIM

Chronic cerebral hypoxia often leads to brain damage and inflammation. Propofol is suggested to have neuroprotective effects under anaesthesia.

MATERIALS AND METHODS

This study used rat models with carotid artery coarctation or closure. Four groups of rats were compared: a control group, a propofol-treated group, a group with bilateral common carotid artery blockage (BCAO), and a BCAO group treated with propofol post-surgery.

RESULTS

The Morris water maze test indicated cognitive impairment in BCAO rats, which also showed hippocampal structure changes, oxidative stress markers alteration, and reduced Klotho expression. Propofol treatment post-BCAO surgery improved these outcomes, suggesting its potential in mitigating chronic cerebral hypoxia effects.

CONCLUSION

Propofol may increase klotho levels and reduce apoptosis and inflammation linked to oxidative stress in cognitively impaired mice.

Cellular senescence in acute kidney injury: Target and opportunity

Acute kidney injury (AKI) is a common clinical disease with a high incidence and mortality rate. It typically arises from hemodynamic alterations, sepsis, contrast agents, and toxic drugs, instigating a series of events that culminate in tissue and renal damage. This sequence of processes often leads to acute renal impairment, prompting the initiation of a repair response. Cellular senescence is an irreversible arrest of the cell cycle. Studies have shown that renal cellular senescence is closely associated with AKI through several mechanisms, including the promotion of oxidative stress and inflammatory response, telomere shortening, and the down-regulation of klotho expression. Exploring the role of cellular senescence in AKI provides innovative therapeutic ideas for both the prevention and treatment of AKI. Furthermore, it has been observed that targeted removal of senescent cells in vivo can efficiently postpone senescence, resulting in an enhanced prognosis for diseases associated with senescence. This article explores the effects of common anti-senescence drugs senolytics and senostatic and lifestyle interventions on renal diseases, and mentions the rapid development of mesenchymal stem cells (MSCs). These studies have taken senescence-related research to a new level. Overall, this article comprehensively summarizes the studies on cellular senescence in AKI, aiming is to elucidate the relationship between cellular senescence and AKI, and explore treatment strategies to improve the prognosis of AKI.

Serum Klotho and insulin resistance: Insights from a cross-sectional analysis

The prevalence of diabetes has surged globally, posing significant health and economic burdens. Insulin resistance underlies the initiation and development of type 2 diabetes. Klotho is a crucial endogenous antiaging factor, associated with atherosclerotic cardiovascular diseases, cancer, neurological disorders, and renal diseases. It additionally has a function in controlling glucose metabolism and holds promise as a new therapeutic target for diabetes. However, its relationship with insulin resistance remains unclear. This study utilizes the National Health and Nutrition Examination Survey (NHANES) 2007 to 2016 data to investigate the relationship between serum Klotho concentrations and insulin resistance. In this observational study, information from the NHANES spanning 2007 to 2016 was employed. The sample consisted of 6371 participants. Weighted linear regression model and chi-square tests were utilized to assess differences in continuous and categorical variables, respectively, among groups categorized by Klotho quartiles. The relationship between Klotho and HOMA-IR (homeostatic model assessment of insulin resistance) was studied using multiple linear regression. Smooth curve fitting was used to analyze nonlinear relationships and the inflection point was determined through a 2-stage linear regression method. After adjusting for multiple confounding factors, serum Klotho levels were found to be positively correlated with insulin resistance [0.90 (0.68, 1.13)]. This correlation is nonlinear and exhibits a saturation effect, with the inflection point identified at 1.24 pg/µL. When Klotho levels are below 1.24 pg/µL, for every unit increase in Klotho, HOMA-IR increases by 1.30 units. Conversely, when Klotho levels exceed 1.24 pg/µL, there is no correlation between HOMA-IR and Klotho. Subgroup analysis reveals that the relationship between HOMA-IR and Klotho varies depending on diabetes and body mass index (BMI). This positive correlation was most prominent in the obese nondiabetic population. There is a positive correlation between serum Klotho and insulin resistance.

Serum klotho levels and mortality patterns in frail individuals: unraveling the u-shaped association

BACKGROUND

Frailty, a clinical syndrome intricately linked with the aging process, stands as a harbinger of numerous adverse outcomes, most notably mortality. This study aimed to elucidate the association between serum α-klotho concentration and mortality patterns, including all-cause and cause-specific mortality, in patients with frailty.

METHODS

The study employed Cox proportional hazard models, smoothed curve fitting, and supplementary analyses, encompassing threshold effect analysis, subgroup and sensitivity analyses, to explore the relationship between α-klotho levels and mortality, including all-cause, CVD, and cancer-related mortality.

RESULTS

Among the 2,608 frail individuals (mean age: 60.78 [SD 10.48] years; 59.89% female), the mortality stood at 25.35% during a median follow-up period of 6.95 years. Both unadjusted and adjusted models revealed a significant inverse association between higher serum α-klotho levels and the risk of all-cause and CVD-related mortality ([mean(95% CI) 0.68 (0.55, 0.83)] for all-cause mortality; [mean(95% CI) 0.48 (0.32, 0.74)] for CVD-related mortality, all P for trend < 0.001). Notably, log2-klotho displayed a U-shaped correlation with all-cause mortality and cancer mortality, characterized by thresholds of 9.48 and 9.55, respectively. The robustness of these findings was consistently supported by subgroup and sensitivity analyses.

CONCLUSION

This study unveils a U shaped association between serum α-klotho levels and both all-cause and cancer-related mortality among middle-aged and elderly individuals with frailty in the United States. The identified serum α-klotho thresholds, at 714.8 pg/ml for all-cause mortality and 750.6 pg/ml for cancer-related mortality, hold promise as potential targets for interventions aimed at mitigating the risks of premature death and cancer within this vulnerable population.

α-Klotho levels in girls with central precocious puberty: potential as a diagnostic and monitoring marker

Background

Recent studies suggest a link between the Klotho protein, sex hormones, and insulin-like growth factor-1 (IGF-1), indicating that α-Klotho levels may rise during puberty, including in central precocious puberty (CPP) cases. This study aimed to explore α-Klotho levels in girls with CPP to assess its potential as a diagnostic and monitoring tool for this condition.

Methods

In total, 139 girls, comprising 82 patients diagnosed with CPP and 57 healthy prepubertal controls, were enrolled in this study. From March 2020 to May 2023, we assessed both α-Klotho levels and clinical parameters. α-Klotho concentrations were measured using an α-Klotho ELISA kit. For the girls with CPP, we additionally analyzed samples taken 6 months after GnRH agonist treatment.

Results

α-Klotho levels were higher in the CPP group compared with the control (CPP group: 2529 ± 999 ng/mL; control group: 1802 ± 675 pg/mL) (P < 0.001), and its level modest decreased after 6 months of GnRH agonist treatment (2147± 789 pg/mL) (P < 0.001). The association between α-Klotho and IGF-1 SDS, follicular stimulating hormone and baseline luteinizing hormone was assessed by partial correlation after adjusting for age, BMI SDS (r= 0.416, p= <0.001; r= 0.261, p= 0.005; r= 0.278, p= 0.002), respectively. Receiver operating characteristic curve analysis identified an α-Klotho cut-off differentiating CPP from controls, with a cut-off of 1914 pg/mL distinguishing girls with CPP from controls with a sensitivity of 69.5% and specificity of 70.2%; the area under the curve was 0.723.

Conclusion

The findings of our study are the first step towards deciphering the role of α-Klotho in puberty induction. With additional data and further research, α-Klotho could potentially be utilized as a significant diagnostic and monitoring tool for CPP.

Anemia and Its Connections to Inflammation in Older Adults: A Review

Anemia is a common hematological disorder that affects 12% of the community-dwelling population, 40% of hospitalized patients, and 47% of nursing home residents. Our understanding of the impact of inflammation on iron metabolism and erythropoiesis is still lacking. In older adults, anemia can be divided into nutritional deficiency anemia, bleeding anemia, and unexplained anemia. The last type of anemia might be caused by reduced erythropoietin (EPO) activity, progressive EPO resistance of bone marrow erythroid progenitors, and the chronic subclinical pro-inflammatory state. Overall, one-third of older patients with anemia demonstrate a nutritional deficiency, one-third have a chronic subclinical pro-inflammatory state and chronic kidney disease, and one-third suffer from anemia of unknown etiology. Understanding anemia's pathophysiology in people aged 65 and over is crucial because it contributes to frailty, falls, cognitive decline, decreased functional ability, and higher mortality risk. Inflammation produces adverse effects on the cells of the hematological system. These effects include iron deficiency (hypoferremia), reduced EPO production, and the elevated phagocytosis of erythrocytes by hepatic and splenic macrophages. Additionally, inflammation causes enhanced eryptosis due to oxidative stress in the circulation. Identifying mechanisms behind age-related inflammation is essential for a better understanding and preventing anemia in older adults.

SPCS, a Novel Classifier System Based on Senescence Axis Regulators Reveals Tumor Microenvironment Heterogeneity and Guides Frontline Therapy for Clear Cell Renal Carcinoma

RATIONALE

The emerging evidence suggested that senescence regulator genes were involved in multi cancers, which may be utilized as new targets for cancers. However, the dysregulation and clinical impact of senescence regulator genes in clear cell renal cell cancer (ccRCC) were still in foggy.

METHODS

Using multiomics data from TCGA-KIRC and other datasets, we comprehensively investigated the function of senescence regulator genes in ccRCC. ccRCC patients could be remodeled into 2 significant different groups basing on senescence regulators expression: senescence-pattern cancer subtype1 (SPCS1) and subtype2 (SPCS2). We further explored clinical characteristics, functional analysis, tumor immune microenvironment, immunotherapy response, genomic mutation and drug sensitivity between the 2 subtypes. Besides, senescence-pattern related risk model was established to determine the patient's prognosis of ccRCC. Finally, the overview of MECP2 function was investigated in multi cancers.

RESULTS

ccRCC patients could be divided into SPCS1 (normal aging group) and SPCS2 (Aging disorder group). The 2 subtypes showed significant different clinical characteristics and biological process in ccRCC. SPCS2, an aggressive subtype, comprised higher clinical stage and worse prognosis of ccRCC patients. SPCS2 subtype indicated activated oncogenic signaling pathway and metabolic signatures to prompt cancer expansion. SPCS2 subgroup owned immunocompromised status, which induced immune dysfunction and low ICI therapy response. The genome-copy numbers of SPCS2, including arm-gain and arm-loss was significantly more frequent than SPCS1. In addition, the 2 subtypes argue contrasting drug sensitivity profiles in clinical specimens and matched cell lines. Finally, we constructed a prognostic risk model consisted of each subtype's leading biomarkers, which exerted a satisfied performance for ccRCC patients.

CONCLUSION

Senescence regulator-related signature could modify functional pathways and tumor immune microenvironment by genome mutation and pathway interaction. Senescence regulator-related molecular subtype strengthen the understanding of ccRCC' characterization and guide clinical treatment. Targeting senescence regulators may be regard as a proper way in ccRCC.

Role of deleterious nsSNPs of klotho protein and their drug response: a computational mechanical insights

Worldwide, the burden of chronic kidney disease (CKD) has increased rapidly and is a lethal disease. The klotho protein plays a vital role in the regulatory mechanism in the progression of CKD. Particularly the decreased expression of klothoand its genetic variations might affect the potency of drugs. This study aims to identify a new drug molecule, which works equipotential in all types of klotholike wild and mutant variants. All non-synonymous SNPs were predicted by several SNP tools. Where, two missense variants were examined as vulnerable, significantly damaging, and also involved in the structural conformational changes of the protein. Based on structure-based screening, E-pharmacophore screening, binding mode analysis, binding free energy analysis, QM/MM, and molecular dynamics analysis a lead compound (Lifechemical_F2493-2038) was identified as an effective agonistic molecule hence the identified Lifechemical_F2493-2038 compound is well bound to the wild and mutant proteins which found to increase the expression of klotho.Communicated by Ramaswamy H. Sarma.

Urine-derived stem cells: Promising advancements and applications in regenerative medicine and beyond

Currently, stem cells are a prominent focus of regenerative engineering research. However, due to the limitations of commonly used stem cell sources, their application in therapy is often restricted to the experimental stage and constrained by ethical considerations. In contrast, urine-derived stem cells (USCs) offer promising advantages for clinical trials and applications. The noninvasive nature of the collection process allows for repeated retrieval within a short period, making it a more feasible option. Moreover, studies have shown that USCs have a protective effect on organs, promoting vascular regeneration, inhibiting oxidative stress, and reducing inflammation in various acute and chronic organ dysfunctions. The application of USCs has also been enhanced by advancements in biomaterials technology, enabling better targeting and controlled release capabilities. This review aims to summarize the current state of research on USCs, providing insights for future applications in basic and clinical settings.

Bibliometric study and review of Klotho research: global characteristics and trends from 2000 to 2023

BACKGROUND

Although Klotho-related research has seen a significant upsurge, the field lacks comprehensive analytical representation and in-depth exploration of pertinent areas such as prevailing research trends and key focus areas.

METHOD

This review presents a bibliometric analysis of literature data gathered from the Web of Science Core Collection databases from January 1, 2000, to April 30, 2023. Parameters such as co-authorship, co-citation, co-occurrence, and the emergence of publications, countries, categories, references, and keywords were scrutinized predominantly using Citespace software.

RESULTS

Our investigation amassed a total of 3548 papers, with the United States leading in the quantity of publications (1175, accounting for 33.12%), followed by China (867, representing 24.44%), and Japan (439, accounting for 12.37%). While the United States is preeminent in the overall volume of publications, Scotland holds prominence in terms of centrality. Out of a total of 96 subject categories, urology and nephrology (573), and endocrinology and metabolism (542) were the two leading domains of Klotho-related publications. The 2011 paper titled "FGF23 induces left ventricular hypertrophy" by Faul C et al. holds the distinction of being the most frequently cited. The keywords "fibroblast growth factor 23," "phosphate homeostasis," and "functional variants" demonstrated the highest intensity, underscoring the potential of these research areas.

CONCLUSION

As the volume of literature grows, the role of Klotho in disease management and its applicability as a marker in disease progression warrant vigilant tracking and study.

Senescence-regulatory factors as novel circulating biomarkers and therapeutic targets in regenerative medicine for osteoarthritis

Recent discoveries reveal that the chronic presence of senescent cells in osteoarticular tissues provides a focal point of disease development for osteoarthritis (OA). Nevertheless, senescence-regulatory factors associated with OA still need to be identified. Furthermore, few diagnostic- and prognostic-validated biochemical markers (biomarkers) are currently used in clinics to evaluate OA patients. In the future, alongside imaging and clinical examination, detecting senescence-regulatory biomarkers in patient fluids could become a prospective method for disease: diagnosis, monitoring, progression and prognosis following treatment. This review summarizes a group of circulating OA biomarkers recently linked to senescence onset. Remarkably, these factors identified in proteomics, metabolomic and microRNA studies could also have deleterious or protective roles in osteoarticular tissue homeostasis. In addition, we discuss their potentially innovative modulation in combination with senotherapeutic approaches, for long-lasting OA treatment.

Lessons from inducible pluripotent stem cell models on neuronal senescence in aging and neurodegeneration

Age remains the central risk factor for many neurodegenerative diseases including Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis. Although the mechanisms of aging are complex, the age-related accumulation of senescent cells in neurodegeneration is well documented and their clearance can alleviate disease-related features in preclinical models. Senescence-like characteristics are observed in both neuronal and glial lineages, but their relative contribution to aging and neurodegeneration remains unclear. Human pluripotent stem cell-derived neurons provide an experimental model system to induce neuronal senescence. However, the extensive heterogeneity in the profile of senescent neurons and the methods to assess senescence remain major challenges. Here, we review the evidence of cellular senescence in neuronal aging and disease, discuss human pluripotent stem cell-based model systems used to investigate neuronal senescence and propose a panel of cellular and molecular hallmarks to characterize senescent neurons. Understanding the role of neuronal senescence may yield novel therapeutic opportunities in neurodegenerative disease.

Correlation between soluble klotho and chronic kidney disease-mineral and bone disorder in chronic kidney disease: a meta-analysis

We conducted a systematic search across medical databases, including PubMed, Web of Science, EMBASE, and Cochrane Library, up to March 2023. A total of 1944 subjects or individuals from 17 studies were included in our final analysis. The correlation coefficient (r) between sKlotho and calcium was [0.14, (0.02, 0.26)], and a moderate heterogeneity was observed (I2 = 66%, P < 0.05). The correlation coefficient (r) between Klotho and serum phosphate was [- 0.21, (- 0.37, - 0.04)], with apparent heterogeneity (I2 = 84%, P < 0.05). The correlation coefficient (r) between sKlotho and parathyroid hormone and vascular calcification was [- 0.23,(- 0.29, - 0.17); - 0.15, (- 0.23, - 0.08)], with no significant heterogeneity among the studies. (I2 = 40%, P < 0.05; I2 = 30%, P < 0.05). A significant correlation exists between low sKlotho levels and an increased risk of CKD-MBD in patients with CKD. According to the findings, sKlotho may play a role in alleviating CKD-MBD by lowering phosphorus and parathyroid hormone levels, regulating calcium levels, and suppressing vascular calcification. As analysis showed that sKlotho has an important impact on the pathogenesis and progression of CKD-MBD in CKD patients. Nonetheless, further comprehensive and high-quality studies are needed to validate our conclusions.

Antiaging Strategies and Remedies: A Landscape of Research Progress and Promise

Aging is typified by a gradual loss of physiological fitness and accumulation of cellular damage, leading to deteriorated functions and enhanced vulnerability to diseases. Antiaging research has a long history throughout civilization, with many efforts put forth to understand and prevent the effects of aging. Multiple strategies aiming to promote healthy aging and extend the lifespan have been developed including lifestyle adjustments, medical treatments, and social programs. A multitude of antiaging medicines and remedies have also been explored. Here, we use data from the CAS Content Collection to analyze the publication landscape of recent research related to antiaging strategies and treatments. We review the recent advances and delineate trends in research headway of antiaging knowledge and practice across time, geography, and development pipelines. We further assess the state-of-the-art antiaging approaches and explore their correlations with age-related diseases. The landscape of antiaging drugs has been outlined and explored. Well-recognized and novel, currently evaluated antiaging agents have also been summarized. Finally, we review clinical applications of antiaging products with their development pipelines. The objective of this review is to summarize current knowledge on preventive strategies and treatment remedies in the field of aging, to outline challenges and evaluate growth opportunities, in order to further efforts to solve the problems that remain.

The influence of Klotho protein and prooxidant-antioxidant balance combination on the mortality of HD patients

PURPOSE

End-stage renal disease patients on chronic hemodialysis (HD) have a shortened life expectancy compared to the general population. The aim of this study was to evaluate a possible link between three new and emerging factors in renal pathophysiology: Klotho protein, telomere length in peripheral blood mononuclear cells (TL) and redox status parameters before HD (bHD) and after HD (aHD), and to test mortality prediction capability of these emerging parameters in a population of HD patients.

METHODS

The study included 130 adult patients with average age 66 (54-72), on HD (3 times per week; 4-5 h per session). Klotho level, TL, routine laboratory parameters, dialysis adequacy and redox status parameters: advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB), superoxide anion (O2.-), malondialdehyde (MDA), ischemia-modified albumin (IMA), total sulfhydryl group content (SHG), and superoxide dismutase (SOD) were determined.

RESULTS

Klotho concentration was significantly higher aHD; 68.2 (22.6-152.9) vs. bHD 64.2 (25.5-119.8) (p = 0.027). The observed increase in TL was not statistically significant. AOPP, PAB, SHG, and SOD activity were significantly increased aHD (p > 0.001). The patients with the highest mortality risk score (MRS) had significantly higher PAB bHD (p = 0.002). Significantly lower O2.- (p < 0.001), SHG content (p = 0.072), and IMA (p = 0.002) aHD were found in patients with the lowest MRS values. Principal component analysis revealed redox balance-Klotho factor as a significant predictor of high mortality risk (p = 0.014).

CONCLUSION

Decreased Klotho and TL attrition as well as redox status disturbance could be connected with higher mortality rate in HD patients.

Breast cancer, alcohol, and phosphate toxicity

Alcohol consumption is associated with an increased risk of breast cancer, even at low alcohol intake levels, but public awareness of the breast cancer risk associated with alcohol intake is low. Furthermore, the causative mechanisms underlying alcohol's association with breast cancer are unknown. The present theoretical paper uses a modified grounded theory method to review the research literature and propose that alcohol's association with breast cancer is mediated by phosphate toxicity, the accumulation of excess inorganic phosphate in body tissue. Serum levels of inorganic phosphate are regulated through a network of hormones released from the bone, kidneys, parathyroid glands, and intestines. Alcohol burdens renal function, which may disturb the regulation of inorganic phosphate, impair phosphate excretion, and increase phosphate toxicity. In addition to causing cellular dehydration, alcohol is an etiologic factor in nontraumatic rhabdomyolysis, which ruptures cell membranes and releases inorganic phosphate into the serum, leading to hyperphosphatemia. Phosphate toxicity is also associated with tumorigenesis, as high levels of inorganic phosphate within the tumor microenvironment activate cell signaling pathways and promote cancer cell growth. Furthermore, phosphate toxicity potentially links cancer and kidney disease in onco-nephrology. Insights into the mediating role of phosphate toxicity may lead to future research and interventions that raise public health awareness of breast cancer risk and alcohol consumption.

Klotho: a potential therapeutic target in aging and neurodegeneration beyond chronic kidney disease-a comprehensive review from the ERA CKD-MBD working group

Klotho, a multifunctional protein, acts as a co-receptor in fibroblast growth factor 23 and exerts its impact through various molecular pathways, including Wnt, hypoxia-inducible factor and insulin-like growth factor 1 pathways. The physiological significance of Klotho is the regulation of vitamin D and phosphate metabolism as well as serving as a vital component in aging and neurodegeneration. The role of Klotho in aging and neurodegeneration in particular has gained considerable attention. In this narrative review we highlight several key insights into the molecular basis and physiological function of Klotho and synthesize current research on the role of Klotho in neurodegeneration and aging. Klotho deficiency was associated with cognitive impairment, reduced growth, diminished longevity and the development of age-related diseases in vivo. Serum Klotho levels showed a decline in individuals with advanced age and those affected by chronic kidney disease, establishing its potential diagnostic significance. Additionally, multiple medications have been demonstrated to influence Klotho levels. Therefore, this comprehensive review suggests that Klotho could open the door to novel interventions aimed at addressing the challenges of aging and neurodegenerative disorders.

Interplay of Systemic Immune-Inflammation Index and Serum Klotho Levels: Unveiling a New Dimension in Rheumatoid Arthritis Pathology

Aim: The association between the systemic immune-inflammation index (SII) and serum Klotho concentrations (pg/ml) in patients with rheumatoid arthritis (RA) has not been elucidated. The purpose of this study was to clarify the relationship between the SII and serum Klotho concentrations in RA patients. Methods: All data come from the National Health and Nutrition Examination Survey (NHANES) database in the United States, which included 982 RA patients (age range: 40 to 79 years). The measurement data of the SII and serum Klotho are all from the NHANES mobile examination centre. We constructed a multivariate linear regression model to evaluate the association between the SII and serum Klotho levels in RA patients and conducted a subgroup analysis to test the stability of the statistical results. Results: Multivariate linear regression results indicated a negative linear relationship between the SII and serum Klotho concentrations in RA patients (β = -6.33, 95% CI [confidence interval]: -10.15 to -2.53). Compared to the quartile 1 group, the quartile 4 group was associated with significantly lower (P<0.001) serum Klotho concentrations (β = -120.93, 95% CI: -174.84 to -67.02). Compared with the quartile 1 group, with the increase in the SII, the β value showed a decreasing trend (P trend < 0.001). The subgroup analysis showed that none of the covariates affected the stability of these results (all P for interaction ≥ 0.05). Conclusion: There is a significant negative linear association between the SII and serum Klotho concentrations in RA patients. The SII can serve as a predictive indicator of serum Klotho concentrations in RA patients, and Klotho may be a potential anti-inflammatory target for RA treatment.

Klotho activation of Nrf2 inhibits the ferroptosis signaling pathway to ameliorate sepsis-associated acute kidney injury

Background

Sepsis-associated acute kidney injury (SA-AKI) is a common complication of sepsis and greatly increases patient mortality. Recombinant human Klotho protein (Klotho) is a protective protein that can be secreted by the kidney. The aim of this study was to explore the protective effect of Klotho on SA-AKI and its molecular mechanism.

Methods

In vivo, a mouse SA-AKI model was constructed by cecum ligation perforation (CLP). In vitro, a human renal tubular cell epithelial cell line (HK2) was induced with lipopolysaccharide (LPS) in the SA-AKI model. Determine renal injury markers, inflammatory factors, oxidative stress and molecular proteins related to the ferroptosis signaling pathway.

Results

Klotho reduced the release of renal injury markers and inflammatory cytokines, decreased oxidative stress, improved renal histopathological changes, ameliorated mitochondrial damage in mouse renal tubular epithelial cells, increased HK2 cell viability and reduced reactive oxygen species (ROS) accumulation. Exogenous supplementation with Klotho increased the Klotho content in circulating blood, renal tissue and HK2 cells.

Conclusions

In the SA-AKI model, Klotho attenuated renal tissue injury, increased HK2 cell viability, decreased inflammatory factor expression and oxidative stress, restored tubular epithelial mitochondrial function, and increased its level in circulating blood, renal tissue and HK2 cells. Klotho probably exerts its protective effects by activating Nrf2 to inhibit the ferroptosis signaling pathway.

The location, physiology, pathology of hippocampus Melatonin MT2 receptor and MT2-selective modulators

Melatonin, a neurohormone secreted by the pineal gland and regulated by the suprachiasmatic nucleus (SCN) of the hypothalamus, is synthesized and directly released into the cerebrospinal fluid (CSF) of the third ventricle (3rdv), where it undergoes rapid absorption by surrounding tissues to exert its physiological function. The hippocampus, a vital structure in the limbic system adjacent to the ventricles, plays a pivotal role in emotional response and memory formation. Melatonin MT1 and MT2 receptors are G protein-coupled receptors (GPCRs) that primarily mediate melatonin's receptor-dependent effects. In comparison to the MT1 receptor, the widely expressed MT2 receptor is crucial for mediating melatonin's biological functions within the hippocampus. Specifically, MT2 receptor is implicated in hippocampal synaptic plasticity and memory processes, as well as neurogenesis and axogenesis. Numerous studies have demonstrated the involvement of MT2 receptors in the pathophysiology and pharmacology of Alzheimer's disease, depression, and epilepsy. This review focuses on the anatomical localization of MT2 receptor in the hippocampus, their physiological function in this region, and their signal transduction and pharmacological roles in neurological disorders. Additionally, we conducted a comprehensive review of MT2 receptor ligands used in psychopharmacology and other MT2-selective ligands over recent years. Ultimately, we provide an outlook on future research for selective MT2 receptor drug candidates.

Organ aging signatures in the plasma proteome track health and disease

Animal studies show aging varies between individuals as well as between organs within an individual1-4, but whether this is true in humans and its effect on age-related diseases is unknown. We utilized levels of human blood plasma proteins originating from specific organs to measure organ-specific aging differences in living individuals. Using machine learning models, we analysed aging in 11 major organs and estimated organ age reproducibly in five independent cohorts encompassing 5,676 adults across the human lifespan. We discovered nearly 20% of the population show strongly accelerated age in one organ and 1.7% are multi-organ agers. Accelerated organ aging confers 20-50% higher mortality risk, and organ-specific diseases relate to faster aging of those organs. We find individuals with accelerated heart aging have a 250% increased heart failure risk and accelerated brain and vascular aging predict Alzheimer's disease (AD) progression independently from and as strongly as plasma pTau-181 (ref. 5), the current best blood-based biomarker for AD. Our models link vascular calcification, extracellular matrix alterations and synaptic protein shedding to early cognitive decline. We introduce a simple and interpretable method to study organ aging using plasma proteomics data, predicting diseases and aging effects.

The Role of Autophagy in Type 2 Diabetic Kidney Disease Management

Diabetic kidney disease (DKD), or diabetic nephropathy (DN), is one of the most prevalent complications of type 2 diabetes mellitus (T2DM) and causes severe burden on the general welfare of T2DM patients around the world. While several new agents have shown promise in treating this condition and potentially halting the progression of the disease, more work is needed to understand the complex regulatory network involved in the disorder. Recent studies have provided new insights into the connection between autophagy, a physiological metabolic process known to maintain cellular homeostasis, and the pathophysiological pathways of DKD. Typically, autophagic activity plays a role in DKD progression mainly by promoting an inflammatory response to tissue damage, while both overactivated and downregulated autophagy worsen disease outcomes in different stages of DKD. This correlation demonstrates the potential of autophagy as a novel therapeutic target for the disease, and also highlights new possibilities for utilizing already available DN-related medications. In this review, we summarize findings on the relationship between autophagy and DKD, and the impact of these results on clinical management strategies.

Ageing-Related Alterations in Renal Epithelial Glucose Transport

The kidney plays a crucial role in glucose homeostasis by regulating glucose transport. We aimed to investigate the impact of alterations in glucose transport on glucose metabolism during ageing. Adult male Sprague Dawley rats were divided into five groups: 3-month, 6-month, and 12-month control groups, and 6- and 12-month groups receiving the hydrogen sulfide donor molecule GYY4137. The study found that, as age increased, daily urinary uric acid and protein levels increased in the 12-month group. Blood sugar level and HOMA-IR index increased in the 12-month group, and were partially improved by GYY4137. The kidney tissue showed mild glomerulosclerosis in the 12-month group, which was diminished by GYY4137. Gene expression analysis showed decreased sirtuin and increased p21 expression in the aging groups. Increased SGLT1 and SGLT2 expression was observed in the 12-month group, which was reversed by GYY4137. Both GLUT1 and GLUT2 expression was increased in the 6- and 12-month groups, and reversed by GYY4137 in the 12-month group. The study concluded that aging was associated with increased blood sugar levels and the HOMA-IR index, and the abundance of renal glucose transporters increased as aging progressed. GYY4137 effectively reversed aging-related alterations in glucose homeostasis and renal epithelial transporters.

[Molecular and cellular mechanisms of ageing: modern knowledge (literature review)]

Ageing (as known as eldering, senescence) is a genetically and epigenetically programmed pathophysiological process. Velocity of biological ageing is defined as balance between alteration and reparation of body structures. According to last World Health Organization (WHO) highlights ageing still stays an extremely actual scientific, social and demographic problem: in 2020 total number of people older than 60 years and older was 1 billion people; in 2030 future number may be 1,4 billion people, in 2050 - 2,1 billion people. Absence of single universal theory of aging nowadays is reason for scientifical and clinical collaboration between biologists and doctors, including endocrinologists. Designing of potentially effective newest anti-ageing strategies (such as natural/synthetic telomerase regulators, mesenchymal stem cells etc.) is of interest to scientific community. The aim of present article is a review of modern omics (genomic, proteomic, metabolomic) ageing mechanisms, potential ways of targeted prevention and treatment of age-related disease according to conception of personalized medicine. Present review is narrative, it does not lead to systematic review, meta-analysis and does not aim to commercial advertisement. Review has been provided via PubMed article that have been published since 1979 until 2022.

N6-methyladenosine methylation in kidney injury

Multiple mechanisms are involved in kidney damage, among which the role of epigenetic modifications in the occurrence and development of kidney diseases is constantly being revealed. However, N6-methyladenosine (M6A), a well-known post-transcriptional modification, has been regarded as the most prevalent epigenetic modifications in higher eukaryotic, which is involved in various biological processes of cells such as maintaining the stability of mRNA. The role of M6A modification in the mechanism of kidney damage has attracted widespread attention. In this review, we mainly summarize the role of M6A modification in the progression of kidney diseases from the following aspects: the regulatory pattern of N6-methyladenosine, the critical roles of N6-methyladenosine in chronic kidney disease, acute kidney injury and renal cell carcinoma, and then reveal its potential significance in the diagnosis and treatment of various kidney diseases. A better understanding of this field will be helpful for future research and clinical treatment of kidney diseases.

Epigenetic roles in clonal hematopoiesis and aging kidney-related chronic kidney disease

Accumulation of somatic hematopoietic stem cell mutations with aging has been revealed by the recent genome-wide analysis. Clonal expansion, known as clonal hematopoiesis of indeterminate potential (CHIP), is a premalignant condition of hematological cancers. It is defined as the absence of definitive morphological evidence of a hematological neoplasm and occurrence of ≥2% of mutant allele fraction in the peripheral blood. In CHIP, the most frequently mutated genes are epigenetic regulators such as DNMT3A, TET2, and ASXL1. CHIP induces inflammation. CHIP is shown to be associated with not only hematological malignancy but also non-malignant disorders such as atherosclerosis, cardiovascular diseases and chronic liver disease. In addition, recent several large clinical trials have shown that CHIP is also the risk factor for developing chronic kidney disease (CKD). In this review article, we proposed novel findings about CHIP and CHIP related kidney disease based on the recent basic and clinical research. The possible mechanism of the kidney injury in CHIP is supposed to be due to the clonal expansion in both myeloid and lymphoid cell lines. In myeloid cell lines, the mutated macrophages increase the inflammatory cytokine level and induce chronic inflammation. It leads to epigenetic downregulation of kidney and macrophage klotho level. In lymphoid cell lines, CHIP might be related to monoclonal gammopathy of renal significance (MGRS). It describes any B cell or plasma cell clonal disorder that does not fulfill the criteria for cancer yet produces a nephrotoxic monoclonal immunoglobulin that leads to kidney injury or disease. MGRS causes M-protein related nephropathy frequently observed among aged CKD patients. It is important to consider the CHIP-related complications such as hematological malignancy, cardiovascular diseases and metabolic disorders in managing the elderly CKD patients. There are no established therapies for CHIP and CHIP-related CKD yet. However, recent studies have supported the development of effective CHIP therapies, such as blocking the expansion of aberrant HSCs and inhibiting chronic inflammation. In addition, drugs targeting the epigenetic regulation of Klotho in the kidney and macrophages might be therapeutic targets of CHIP in the kidney.

Emerging role of α-Klotho in energy metabolism and cardiometabolic diseases

BACKGROUND AND AIM

Klotho was first identified as a gene associated with aging and longevity in 1997. α-Klotho is an anti-aging protein and its role in energy metabolism, various cardiovascular diseases (CVDs), and metabolic disorders is increasingly being recognized. In this review, we aimed to outline the potential protective role and therapeutic prospects of α-Klotho in energy metabolism and cardiometabolic diseases (CMDs).

METHODS

We comprehensively reviewed the relevant literature in PubMed using the keywords 'Klotho', 'metabolism', 'cardiovascular', 'diabetes', 'obesity', 'metabolic syndrome', and 'nonalcoholic fatty liver disease'.

RESULTS

α-Klotho can be divided into membrane-bound Klotho, secreted Klotho, and the most studied circulating soluble Klotho that can act as a hormone. Klotho gene polymorphisms have been implicated in energy metabolism and CMDs. α-Klotho can inhibit insulin/insulin growth factor-1 signaling and its overexpression can lead to a 'healthy insulin resistance' and may exert beneficial effects on the regulation of glycolipid metabolism and central energy homeostasis. α-Klotho, mainly serum Klotho, has been revealed to be protective against CVDs, diabetes and its complications, obesity, and nonalcoholic fatty liver disease. Human recombinant Klotho protein/Klotho gene delivery, multiple drugs, or natural products, and exercise can increase α-Klotho expression.

CONCLUSION

Overall, α-Klotho has demonstrated its potential as a promising target for modulating energy metabolism and CMDs, and further research is needed to explore its utilization in clinical practice in the future.

Degradation of histone deacetylase 6 alleviates ROS-mediated apoptosis in renal ischemia-reperfusion injury

Renal ischemia reperfusion injury (RIRI) is an inevitable complication during renal surgery. Histone deacetylase 6 (HDAC6), a key member of the histone deacetylase family, is associated with multiple pathologies, including renal diseases. However, whether HDAC6 could become a potential therapeutic target for clinical application of RIRI remained to be proven. Here, we found that HDAC6 expression was abnormally enhanced by the transcription factor OSR2 in RIRI. Moreover, we were the first to validate that a selective HDAC6 degrader, proteolysis-targeting chimeras (PROTAC) NP8, could significantly improve RIRI. Further in vivo and in vitro mechanism studies have found that the reduction of HDAC6 alleviated RIRI by inhibiting ROS mediated apoptosis. Remarkably, a renal protective protein, Klotho, has been proven to be a target of HDAC6, and the degradation of HDAC6 restored KL expression, thereby ameliorating ROS mediated apoptosis. Overall, our results illustrated that the degradation of HDAC6 restrained ROS mediated apoptosis by restoring Klotho expression during RIRI. PROTAC-NP8 might be a potential therapeutic strategy for clinical prevention of RIRI.

Histamine deficiency inhibits lymphocyte infiltration in the submandibular gland of aged mice via increased anti-aging factor Klotho

OBJECTIVES

Histidine decarboxylase (HDC), a histamine synthase, is expressed in various tissues and is induced by proinflammatory cytokines such as TNFα. As they age, C57BL/6 mice show auto-antibody deposition and lymphocyte infiltration into various tissues, including salivary glands. However, the mechanism underlying cell infiltration and the change in HDC expression in salivary glands with aging remain unclear. Thus, we aimed to elucidate the relationship between histamine and inflammaging.

METHODS

We investigated the change in histology and HDC expression in the major salivary glands (parotid, submandibular, and sublingual) of 6-week- and 9-month-old wild-type mice. We also determined the histological changes, cytokine expression, and anti-aging factor Klotho in the salivary glands of 9-month-old wild-type and HDC-deficient (HDC-KO) mice.

RESULTS

Cell infiltration was observed in the submandibular gland of 9-month-old wild-type mice. Although most cells infiltrating the submandibular glands were CD3-positive and B220-positive lymphocytes, CD11c-positive and F4/80-positive monocyte lineages were also detected. HDC, TNFα, and IL-1β mRNA expression increased in the submandibular gland of 9-month-old wild-type mice. The expression of PPARγ, an anti-inflammatory protein, declined in 9-month-old wild-type mice, and Klotho expression increased in 9-month-old HDC-KO mice. Immunohistochemistry showed that Klotho-positive cells disappeared in the submandibular gland of 9-month-old wild-type mice, while Klotho was detected in all salivary glands in HDC-KO mice of the same age.

CONCLUSION

Our findings demonstrate the multifunctionality of histamine and can aid in the development of novel therapeutic methods for inflammatory diseases such as Sjogren's syndrome and age-related dysfunctions.

Tubular injury in diabetic kidney disease: molecular mechanisms and potential therapeutic perspectives

Diabetic kidney disease (DKD) is a chronic complication of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. Currently, there are limited therapeutic drugs available for DKD. While previous research has primarily focused on glomerular injury, recent studies have increasingly emphasized the role of renal tubular injury in the pathogenesis of DKD. Various factors, including hyperglycemia, lipid accumulation, oxidative stress, hypoxia, RAAS, ER stress, inflammation, EMT and programmed cell death, have been shown to induce renal tubular injury and contribute to the progression of DKD. Additionally, traditional hypoglycemic drugs, anti-inflammation therapies, anti-senescence therapies, mineralocorticoid receptor antagonists, and stem cell therapies have demonstrated their potential to alleviate renal tubular injury in DKD. This review will provide insights into the latest research on the mechanisms and treatments of renal tubular injury in DKD.