Klotho Protein and Cardio-Vascular System

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.

Association between Serum α-Klotho Levels and Behçet Disease

BACKGROUND

Endothelial dysfunction (ED) has a well-known role in promoting vascular inflammation in Behçet disease (BD). α-klotho is involved in regulation of endothelial function, and its reduction has been reported to be associated with ED.

OBJECTIVE

To assess serum α-klotho in patients with BD, compared with healthy control individuals.

METHODS

In a cross-sectional study, 55 patients with BD and 30 age- and sex-matched healthy controls were enrolled, and their serum levels of α-klotho were measured.

RESULTS

Common clinical symptoms in patients with BD were oral aphthous ulcers, uveitis, and genital ulcers. Median (IQR) serum α-klotho levels in the BD and control groups were 0.30 (0.20-0.70) and 1.00 (0.70-2.52) ng/mL, respectively. The difference was statistically significant (P = .005). No significant correlation was observed between serum α-klotho and age (r = 0.194; P = .14). Serum α-klotho levels in patients with uveitis were significantly lower.

CONCLUSION

α-klotho may have a role in the pathogenesis of ED and is a potential biomarker for uveitis in BD.

[Synergistic effects of GABA and hypoglycemic drugs]

Diabetes mellitus (DM) is the leading cause of premature death and disability. Despite a significant number of drugs, the effectiveness of therapy aimed at normalizing the level of glycemia and preventing complications does not fully satisfy doctors and patients. Therefore, the search for new approaches for the prevention and treatment of DM and its complications continues. Significant resources are used to develop new drugs, but recently the possibility of using «old» widely available drugs with newly discovered pleiotropic properties has been substantiated. These may include preparations of gammaaminobutyric acid (GABA) and agents that directly or indirectly activate GABAergic transmission, which have a pronounced pancreatic protective effect, which has been widely discussed in foreign literature over the past 10-15 years. However, there are few such publications in the domestic literature.It has been established that the content of GABA in β-cells in patients with type 1 and type 2 diabetes is reduced and this correlates with the severity of the disease. Genetic suppression of GABA receptors causes a significant decrease in the mass of β-cells and glucose-stimulated insulin secretion, which confirms the importance of GABA in ensuring glucose homeostasis and the advisability of replenishing the GABA deficiency in DM with its additional administration. It has been established that in animals with DM, GABA suppresses apoptosis and stimulates the regeneration of β-cells, increases β-cell mass and insulin production.Experimental data have been obtained indicating a synergistic effect of GABA when combined with glucagon-like peptide-1 (GLP-1) receptor agonists, DPP-4 inhibitors and sodium-glucose cotransporter 2 (SGLT-2) inhibitors, when a more pronounced pancreoprotective effect is observed, due to decrease in oxidative and nitrosative stress, inflammation, increase in the level of Klotho protein, Nrf-2 activity and antioxidant defense enzymes, suppression of NF-kB activity and expression of pro-inflammatory cytokines. As a result, all this leads to a decrease in apoptosis and death of β-cells, an increase in β-cell mass, insulin production and, at the same time, a decrease in glucagon levels and insulin resistance.The review substantiates the feasibility of using GABA and drugs with a positive GABAeric effect in combination with new generation antidiabetic agents: GLP-1 receptor agonists, DPP-4 inhibitors and SGLT-2 inhibitors in order to increase their antidiabetic potential.The search was carried out in the databases Pubmed, eLibrary, Medline. Keywords: diabetes mellitus, gamma-aminobutyric acid, glucagon-like peptide-1, GLP-1 receptor agonists, glucose-dependent insulinotropic peptide, dipeptidyl peptidase inhibitors, sodium-glucose cotransporter 2 inhibitors. The search was carried out from 2000 to 2022, but the review presents the results studies published mainly in the last 3 years, due to the requirements of the journal for the maximum amount of work and the number of sources.

The role of Klotho and FGF23 in cardiovascular outcomes of diabetic patients with chronic limb threatening ischemia: a prospective study

Cardiovascular complications after lower extremity revascularization (LER) are common in diabetic patients with peripheral arterial disease (PAD) and chronic limb threatening ischemia (CLTI). The Klotho-fibroblast growth factor 23 (FGF23) axis is associated with endothelial injury and cardiovascular risk. We aimed to analyze the relationship between Klotho and FGF23 serum levels and the incidence of major adverse cardiovascular events (MACE) and major adverse limb events (MALE) after LER in diabetic patients with PAD and CLTI. Baseline levels of Klotho and FGF23, and their association with subsequent incidence of MACE and MALE were analyzed in a prospective, non-randomized study in a population of diabetic patients with PAD and CLTI requiring LER. A total of 220 patients were followed for 12 months after LER. Sixty-three MACE and 122 MALE were recorded during follow-up period. Baseline lower Klotho serum levels (295.3 ± 151.3 pg/mL vs. 446.4 ± 171.7 pg/mL, p < 0.01), whereas increased serum levels FGF23 (75.0 ± 11.8 pg/mL vs. 53.2 ± 15.4 pg/mL, p < 0.01) were significantly associated with the development of MACE. Receiver operating characteristic (ROC) analysis confirmed the predictive power of Klotho and FGF23 baseline levels. Furthermore, decreased Klotho levels were associated with the occurrence of MALE after LER (329.1 ± 136.8 pg/mL vs 495.4 ± 183.9 pg/mL, p < 0.01). We found that Klotho and FGF23 baseline levels are a potential biomarker for increased cardiovascular risk after LER in diabetic patients with PAD and CLTI.

Association between environmental exposure to perchlorate, nitrate, and thiocyanate and serum α-Klotho levels among adults from the National Health and nutrition examination survey (2007–2014)

Background & aims

Aging is a pathophysiological process driven by a diverse set of complex biological processes, and environmental pollution plays an important role in this process. This study aimed to explore the association between serum α-Klotho levels and urinary perchlorate, nitrate, and thiocyanate levels.

Methods

This secondary dataset analysis included 4875 participants (mean age, 57.69 year; male, 49.58%; non-Hispanic White, 47.67%) from the US National Health and Nutrition Examination Survey (2007–2014). Enzyme-linked immunosorbent assay was used to quantify α-Klotho levels, and ion chromatography coupled with electrospray tandem mass spectrometry was used to quantify thiocyanate, nitrate, and perchlorate levels. Multivariate linear regression models were applied to estimate the association between perchlorate, nitrate, and thiocyanate levels and serum α-Klotho levels.

Results

Urinary thiocyanate levels were negatively associated with α-Klotho levels (β = − 0.006; 95% confidence interval, − 0.010 to − 0.003; P = 0.0004) after adjusting for age, sex, body mass index, race, alcohol consumption, estimated glomerular filtration rate, underlying disease, physical activity, smoking status, usual energy intake, and urinary creatinine and serum cotinine levels and mutual adjustment of urinary perchlorate, urinary nitrate, and urinary thiocyanate levels. The α-Klotho level in participants in the highest quartile was higher by 50.567 ng/mL (β = 50.567; 95% confidence interval, 14.407 to 86.726; P = 0.009) than that in participants in the lowest quartile of urinary perchlorate. A linear relationship was observed between urinary thiocyanate and α-Klotho levels.

Conclusions

Urinary thiocyanate levels were negatively associated with serum α-Klotho levels. Urinary thiocyanate should be further investigated as a potential mediator of aging and age-related diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03444-2.

Pathobiology of the Klotho Antiaging Protein and Therapeutic Considerations

The α-Klotho protein (henceforth denoted Klotho) has antiaging properties, as first observed in mice homozygous for a hypomorphic Klotho gene (kl/kl). These mice have a shortened lifespan, stunted growth, renal disease, hyperphosphatemia, hypercalcemia, vascular calcification, cardiac hypertrophy, hypertension, pulmonary disease, cognitive impairment, multi-organ atrophy and fibrosis. Overexpression of Klotho has opposite effects, extending lifespan. In humans, Klotho levels decline with age, chronic kidney disease, diabetes, Alzheimer’s disease and other conditions. Low Klotho levels correlate with an increase in the death rate from all causes. Klotho acts either as an obligate coreceptor for fibroblast growth factor 23 (FGF23), or as a soluble pleiotropic endocrine hormone (s-Klotho). It is mainly produced in the kidneys, but also in the brain, pancreas and other tissues. On renal tubular-cell membranes, it associates with FGF receptors to bind FGF23. Produced in bones, FGF23 regulates renal excretion of phosphate (phosphaturic effect) and vitamin D metabolism. Lack of Klotho or FGF23 results in hyperphosphatemia and hypervitaminosis D. With age, human renal function often deteriorates, lowering Klotho levels. This appears to promote age-related pathology. Remarkably, Klotho inhibits four pathways that have been linked to aging in various ways: Transforming growth factor β (TGF-β), insulin-like growth factor 1 (IGF-1), Wnt and NF-κB. These can induce cellular senescence, apoptosis, inflammation, immune dysfunction, fibrosis and neoplasia. Furthermore, Klotho increases cell-protective antioxidant enzymes through Nrf2 and FoxO. In accord, preclinical Klotho therapy ameliorated renal, cardiovascular, diabetes-related and neurodegenerative diseases, as well as cancer. s-Klotho protein injection was effective, but requires further investigation. Several drugs enhance circulating Klotho levels, and some cross the blood-brain barrier to potentially act in the brain. In clinical trials, increased Klotho was noted with renin-angiotensin system inhibitors (losartan, valsartan), a statin (fluvastatin), mTOR inhibitors (rapamycin, everolimus), vitamin D and pentoxifylline. In preclinical work, antidiabetic drugs (metformin, GLP-1-based, GABA, PPAR-γ agonists) also enhanced Klotho. Several traditional medicines and/or nutraceuticals increased Klotho in rodents, including astaxanthin, curcumin, ginseng, ligustilide and resveratrol. Notably, exercise and sport activity increased Klotho. This review addresses molecular, physiological and therapeutic aspects of Klotho.

Association between serum cotinine and α-Klotho levels among adults: Findings from the National Health and Nutrition Examination Survey 2007–2016

INTRODUCTION

Serum cotinine is a sensitive and specific marker of tobacco smoke exposure. α-Klotho is an anti-ageing molecule, which plays an important role in several diseases. We aimed to examine the association between smoke exposure indicated by the serum cotinine and α-Klotho levels, as previous reports regarding the level of α-Klotho in smokers have been inconsistent.

METHODS

This secondary dataset analysis included 9833 participants (aged 40–79 years; 47.0% females and 53.0% males) from the US National Health and Nutrition Examination Survey 2007–2016. Independent variables were serum cotinine level, age, sex, race, body mass index (BMI), and alcohol consumption. The outcome variable was serum α-Klotho level. Multiple linear regression analysis was used to examine the association between serum cotinine and α-Klotho levels.

RESULTS

The serum cotinine level was negatively associated with the α-Klotho level (β= -0.107, 95% CI: -0.155 to -0.059, p<0.0001) after adjusting for age, BMI, sex, race, and alcohol consumption. The α-Klotho level in participants with cotinine ≥3 ng/mL decreased by 44.514 pg/mL (p<0.0001) compared to that in participants with cotinine <3 ng/mL. There is a non-linear relationship between serum cotinine and α-Klotho levels. The piecewise linear models indicated a significant threshold effect between serum cotinine and α-Klotho levels. On the left of the inflection point (cotinine <130 ng/mL), the serum cotinine level increased with decreased α-Klotho level (β= -0.519, 95% CI: -0.682 to -0.356). On the right of the inflection point (cotinine ≥130 ng/mL), the serum cotinine level increased with increased α-Klotho level (β=0.085, 95% CI: 0.000 to 0.170).

CONCLUSIONS

Based on our study results, serum cotinine level was associated with the serum α-Klotho level.

Renal Function Mediates the Association Between Klotho and Congestive Heart Failure Among Middle-Aged and Older Individuals

Objective

Using a newly released National Health and Nutrition Examination Survey (NHANES) data of serum Klotho, this study aimed to explore the relationship between Klotho and specific cardiovascular diseases (CVD), as well as the mediation effect of renal function, among middle-aged and older individuals within the general population.

Methods

This nationally representative cross-sectional study analyzed data from the 2007–2016 NHANES. A total of 13,765 participants, who aged 40 years or older, from the general population were examined. Klotho were divided into four groups based on median and interquartile range. The associations among Klotho (exposure), congestive heart failure (CHF; outcome), and renal function markers [estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), uric acid (UA), and urine albumin-to-creatinine ratio (UACR); mediators] were investigated using mediation analysis.

Results

In comparison to the lowest quartile, Klotho in the highest quartile was independently associated with the prevalence of CHF (OR 0.59; 95% CI 0.46–0.77, p for trend = 0.001), but not with other individual CVDs. Klotho had a significant direct effect on the prevalence of CHF (all p < 0.001), while eGFR, BUN, UA, and UACR partly mediated the indirect effect of Klotho on the prevalence of CHF (all p < 0.05), explaining 19.51, 6.98, 13.93, and 0.71% of the association between Klotho and CHF, respectively. Additionally, restricted cubic spline regression demonstrated a linear association and negative correlation between Klotho level and CHF.

Conclusion

These findings suggest that Klotho is closely linked to CHF and renal function may be a key mediator of this association.