Soluble Klotho and Incident Hypertension

Association of serum klotho level with albuminuria in middle‑aged and elderly participants without diabetes mellitus: a cross‑sectional study

BACKGROUND

The relationship between serum klotho level and albuminuria is unknown in middle-aged and elderly participants without diabetes mellitus (DM). Therefore, we will investigate the association between serum klotho level and albuminuria in middle-aged and elderly participants without DM.

METHODS

Participants (aged 40-79) were from the five continuous cycles (2007-2016) of the National Health and Nutrition Examination Survey (NHANES). Multiple logistic regression was performed to investigate the association between serum klotho level and albuminuria.

RESULTS

9217 participants were included in the present study. 47.6% of the participants were male. The average age of the overall participants was 56.3 years (40-79 years). Overall, 823 participants with albuminuria were identified. After adjusted confounders (age, gender, marital status, ethnicity, family income to poverty ratio, education, body mass index, smoke, charlson comorbidity index, hypertension, hyperlipidemia, angiotensin converting enzyme inhibitor/angiotonin receptor blocker, and estimated glomerular filtration rate), participants with a high serum klotho level had a decreased risk for albuminuria. Compared with the lowest serum klotho level (Tertile 1), participants in Tertile 2 (odds ratio [OR] 0.83, 95% CI 0.70-0.99, P = 0.044) and Tertile 3 (OR 0.76, 95% CI 0.63-0.91, P = 0.003) had a lower risk of albuminuria (P for trend = 0.002). The stratified analysis showed that serum klotho level was still negatively associated with albuminuria in the subgroups, and statistically significant interactions were not observed in the subgroups (all P values for interactions > 0.05, except for the hypertension subgroup).

CONCLUSIONS

In middle-aged and elderly participants without DM, a high serum klotho level is associated with a decreased risk of albuminuria. In the future, the mechanism of the interaction between klotho and albuminuria needs to be elucidated to find new treatment targets for individuals without DM who suffer from albuminuria.

Dietary caffeine and its negative link to serum Klotho concentrations: evidence from the National Health and Nutrition Examination Survey

Background

This is the initial investigation assessing the association between caffeine consumption through diet and circulating Klotho concentrations, with Klotho being recognized as a key biomarker of healthspan and aging.

Methods

This cross-sectional analysis utilized data from 11,169 adults who participated in the National Health and Nutrition Examination Survey (NHANES). Caffeine consumption was evaluated using 24-h dietary recall interviews by trained professionals, and serum Klotho concentrations were measured via an enzyme-linked immunosorbent assay (ELISA). Generalized linear models and threshold effect analysis were employed to examine the relationship between caffeine intake and serum Klotho concentrations. Interaction tests and subgroup analyses were conducted to identify potential effect modifiers.

Results

After controlling for covariates, a negative correlation was observed between dietary caffeine consumption and serum Klotho concentrations, with each additional 100 mg of dietary caffeine consumption, Klotho decreased by 3.40 pg./mL (95% confidence interval [CI]: -5.73, -1.07). Participants in the fourth quartile of dietary caffeine consumption showed a 23.00 pg./mL reduction in serum Klotho concentrations (95% CI: -39.41, -6.58) compared to individuals in the first quartile. Threshold effect analysis revealed a threshold point corresponding to natural log-transformed caffeine value >3.74 (equivalent to ~41 mg/day), above which Klotho levels demonstrated a more pronounced decline. Subgroup analyses indicated that this association was more significant in participants with sedentary activity >480 min and without hypertension.

Conclusion

Our study reveals a significant, dose-dependent negative association linking caffeine intake with serum Klotho concentrations in the United States adults aged 40-79 years, with potential thresholds beyond which the effects become more pronounced. Additional studies are required to verify these results and investigate the underlying biological processes involved.

Associations Between Urinary Phthalate Metabolites and Decreased Serum α-Klotho Level: A Cross-Sectional Study Among US Adults in Middle and Old Age

Phthalates are widely used chemicals with ubiquitous human exposure. Evidence indicated that phthalate exposure was associated with an increased risk of aging-related diseases. Klotho is a transmembrane protein with anti-aging functions, and its association with phthalates remains unknown. To find the association between phthalate exposure and serum α-Klotho, a cross-sectional study was performed in 4482 adults (40-79 years old) who completed the National Health and Nutrition Examination Survey (NHANES) (2007-2016). As shown in the results of multivariable linear regression analyses, mono(carboxynonyl) phthalate (MCNP) and mono-n-butyl phthalate (MBP) were inversely associated with α-Klotho, and the regression coefficients of MCNP and MBP were -1.14 (95% confidence interval (CI): -2.00, -0.27) and -0.08 (95% CI: -0.14, -0.02). Subgroup analyses based on the quartiles of each phthalate metabolite showed that both MCNP and MBP were only inversely associated with α-Klotho in the subgroups of the highest levels. For mono-isobutyl phthalate (MIBP), the inverse association with α-Klotho was only statistically significant in the subgroup of the lowest level, and the regression coefficient was -26.87 (95% CI: -52.53, -1.21). Our findings suggest that α-Klotho might be involved in the association of phthalate exposure with aging-related diseases. Future research investigating the causality between phthalates and α-Klotho and its underlying mechanisms is encouraged.

The prognostic value of serum α-klotho in age-related diseases among the US population: A prospective population-based cohort study

Objective

α-Klotho is a potential biological marker of aging with satisfactory clinical applicability. However, its prognostic significance in age-related diseases has largely been undermined. Therefore, we aimed to report the prognostic value of serum α-klotho levels in age-related diseases.

Methods

Participants with available serum α-klotho data from the National Health and Nutrition Examination Survey (2007-2016) were included. Their survival status was collected at 7.62 ± 2.99 years after serum α-klotho data was collected, and the endpoint was all-cause and cardiovascular mortality. A Cox regression model was established to examine the association between serum α-klotho levels and all-cause and cardiovascular mortality.

Results

The present study included 13,746 U.S. adults with a survey-weighted mean age of 56.19 ± 10.42 years old. Of these, 52.2 % were female and 72.9 % were non-Hispanic whites. The optimal cutoff value of serum α-klotho for predicting all-cause mortality risk in the general population was 603.5 pg/ml. Individuals with low serum α-klotho (<603.5 pg/ml) had a significantly higher risk of all-cause (adjusted HR: 1.34(1.18-1.52), P < 0.001) and cardiovascular mortality (adjusted HR: 1.63(1.27-2.10), P < 0.001). Subgroup analysis showed that low serum α-klotho level was an independent risk factor for all-cause and cardiovascular mortality in people with hypertension, congestive heart failure, diabetes mellitus, and emphysema, while it was an independent risk factor for all-cause mortality in patients with renal insufficiency.

Conclusion

A low serum α-klotho concentration (<603.5 pg/ml) could serve as a marker of all-cause and cardiovascular mortality in the general population and in people with age-related diseases, including hypertension, congestive heart failure, diabetes mellitus, and emphysema.

Association between smoking, smoking cessation and serum α-klotho levels among American adults: National Health and Nutrition Examination Survey

α-klotho is an anti-aging protein. The correlation between smoking, smoking cessation and serum α-klotho levels remains controversial. The aim of this study was to investigate the association between smoking, smoking cessation and serum α-klotho levels. This cross-sectional study finally included 4877 participants, aged 40-79 years, who participated in the National Health and Nutrition Examination Survey studies from 2013 to 2016. Of these, 2312 (47.4%) were men and 894 (18.3%) were current smokers, and the mean age of the participants was 57.8±10.7 years. Multivariate linear regression modeling was used to assess the association between smoking, smoking cessation and serum α-klotho levels. After adjustment for multiple confounders, this study observed that smoking was negatively associated with serum α-klotho levels (β: -58.3; 95% confidence interval CI: -82.0 to -34.6; p<0.001), whereas smoking cessation was positively associated with serum α-klotho levels (β: 52.3; 95% CI: 24.1 to 80.6; p<0.001). In subgroup and interaction analyses, p-value for the interaction between smoking and race on serum klotho levels was found to be less than 0.001. The correlation between smoking, smoking cessation and serum α-klotho levels remained stable after propensity score matching (β: -54.1; 95% CI: -81.5 to -26.7; p<0.001, β: 54.8; 95% CI: 24.2 to 85.4; p<0.001). In a large sample population, the present study found that smoking, smoking cessation and serum α-klotho levels were associated in opposite directions.

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.

Birth size and the serum level of biological age markers in men

Previous studies showed that intrauterine growth restrictions, resulting in smaller body size at birth, are associated with altered development and the risk of age-related diseases in adult life. Thus, prenatal development may predict aging trajectories in humans. The study aimed to verify if body size at birth is related to biological age in adult men. The study sample consisted of 159 healthy, non-smoking men with a mean age of 35.24 (SD 3.44) years. Birth weight and length were taken from medical records. The ponderal index at birth was calculated. Biological age was evaluated based on serum levels of s-Klotho, hsCRP, DHEA/S, and oxidative stress markers. Pregnancy age at birth, lifestyle, weight, cortisol, and testosterone levels were controlled. The results showed no relationship between birth size and s-Klotho, DHEA/S level, inflammation, or oxidative stress. Also, men born as small-for-gestational-age (N = 49) and men born as appropriate-for-gestational-age (N = 110) did not differ in terms of biological age markers levels. The results were similar when controlled for pregnancy week at birth, chronological age, BMI, testosterone, or cortisol level. The results suggest that there is no relationship between intrauterine growth and biomarkers of aging in men aged 30-45 years from the affluent population.

The association of serum Klotho concentrations with hyperlipidemia prevalence and lipid levels among US adults: a cross-sectional study

BACKGROUND

Klotho has anti-oxidative and anti-inflammatory properties. However, little is known about whether high Klotho concentrations were associated with reduced hyperlipidemia risk and improved plasma lipid levels.

METHODS

Participants with complete data on serum Klotho and plasma lipid concentrations from the 2007-2016 National Health and Nutrition Examination Survey were included. Weighted regression models were fitted to explore the association of Klotho concentrations with hyperlipidemia risk and plasma lipid levels while restricted cubic spline models were applied to explore the dose-response relationship. Additionally, we assessed the mediating effects of C-reaction protein (CRP) on the foregoing association.

RESULTS

Individuals in the fourth and fifth quintile of serum Klotho had an adjusted odds ratio (OR) of 0.77 (95%CI: 0.65, 0.93) and 0.67 (95%CI: 0.65, 0.93) for hyperlipidemia. Doubling of serum Klotho concentrations was associated with decreased hyperlipidemia risk (OR = 0.81; 95%CI: 0.68, 0.95) and triglyceride levels (13.25 mg/dL; 95%CI: 4.02, 22.47), with a monotonic dose-response relationship. Individuals in the fourth and fifth quintile of serum Klotho had a 0.07 (95%CI: 0.002, 0.13), 0.08 (95%CI: 0.02, 0.15) and 0.05 (95%CI: -0.03, 0.12) mg/dL decreased CRP levels, with a marginally significant trend (Ptrend = 0.05).

CONCLUSIONS

Higher Klotho concentrations were associated with reduced hyperlipidemia risk and triglyceride levels. Klotho supplementation maybe a promising method to intervene and prevent hyperlipidemia, but the underlying mechanism should be further explored.

Association between serum Klotho concentration and hypertension in postmenopausal women, a cross-sectional study from NHANES 2013-2016

BACKGROUND

The objective of this study was to examine the correlation between serum Klotho protein concentration and postmenopausal hypertension.

METHODS

A cross-sectional study design was used, in which 1713 postmenopausal women who participated in the National Health and Nutrition Examination Survey (NHANES) 2013-2016 were included. Multivariate logistic regression models were applied to assess the association between serum Klotho concentration and postmenopausal hypertension.

RESULTS

A weighted analysis was executed, revealing a noteworthy hypertension prevalence rate of 53.44% among the study participants. Participants with lower quartile of serum Klotho concentration had a higher prevalence of hypertension than those in higher quartiles (Q1:62.29% vs. Q2: 48.52% vs. Q3: 47.33% vs. Q4: 55.02%, p < 0.001). Furthermore, a multivariate logistic regression analysis confirmed that participants with higher quartiles of serum Klotho concentration had a significantly reduced risk of postmenopausal hypertension compared to those in the lowest quartile. Subgroup analysis displayed consistent findings in those following subgroups: aged ≥ 65 years, obesity, nonsmokers, individuals without diabetes and coronary heart disease, and those with higher levels of estradiol and estimated glomerular filtration rate. Based on the results, we concluded that there is a significant association between serum Klotho concentration and postmenopausal hypertension.

CONCLUSION

The findings of this study revealed a significant inverse association between serum Klotho concentration and hypertension among postmenopausal women. Serum Klotho concentration may serve as a valuable biomarker for risk stratification in postmenopausal women who are at risk of developing hypertension.

The Association between Dietary Fiber Intake and Serum Klotho Levels in Americans: A Cross-Sectional Study from the National Health and Nutrition Examination Survey

BACKGROUND

Klotho is an aging-related marker closely associated with a number of diseases. A growing body of evidence suggests that dietary factors and lifestyle habits can impact serum Klotho levels. The effect of dietary fiber, a key component of a healthy diet, on the body's serum Klotho levels has not been fully elucidated.

OBJECTIVE

The aim of this study was to explore the relationship between dietary fiber intake and serum Klotho levels in people aged 40-79 years in the United States.

METHODS

A total of 11,282 participants were included in this study, all from the National Health and Nutrition Examination Survey from 2007 to 2016. Dietary fiber intake was assessed by uniformly trained interviewers using the 24 h dietary recall method. Serum Klotho was quantified using commercially available ELISA kits manufactured by IBL International, Japan. The relationship between dietary fiber intake and serum Klotho levels was analyzed using a multiple linear regression model. Subsequently, the non-linear dose-response relationship between the two was further explored using a restricted cubic spline (RCS) model.

RESULTS

After adjusting for potential confounders, serum Klotho levels increased by 1.9% (95% confidence interval [CI]: 0.8%, 3.0%) for each interquartile range increase in dietary fiber intake in all participants. Considering dietary fiber intake as a categorical variable, serum Klotho levels were found to be 4.7% higher in participants in the highest quartile of dietary fiber intake than in those in the lowest quartile (95% CI: 1.8%, 7.6%). RCS plots depicted a non-linear positive correlation between dietary fiber intake and serum Klotho levels. Subgroup analysis revealed that the relationship between dietary fiber intake and serum Klotho levels was more pronounced in older (percentage change: 7.0%; 95% CI: 2.5%, 11.7%) and overweight and obese participants (percentage change: 4.9%; 95% CI: 1.5%, 8.4%).

CONCLUSIONS

The results of this study showed that dietary fiber intake was significantly associated with serum Klotho levels in participants. This finding is yet to be further confirmed by prospective studies.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

Associations between concentrations of serum α-klotho and selected urinary monohydroxy metabolites of polycyclic aromatic hydrocarbons: data for US adults aged 40-79 years

For the first time, the associations between urinary concentrations of oxidant polycyclic aromatic hydrocarbon (PAH) metabolites and serum concentrations of anti-oxidant α-klotho were estimated for US adults aged 40-79 years. Multivariate regression models with α-klotho as dependent variable and one of the urinary metabolite of PAH as independent variables were fitted. In the absence of albuminuria and normal (eGFR > 90 mL/min/1.73 m²) kidney function, 10% increases in concentrations of 2-hydroxynaphthalene, 9-hydroxyfluorene, and ∑PAH were associated with 0.25%, 0.32%, and 0.19% decreases in serum α-klotho concentrations. In the absence of albuminuria and near normal (60 <  = eGFR < 90 mL/min/1.73 m²) kidney function, 10% increases in concentrations of 1-hydroxynaphthalene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, and ∑PAH were associated with 0.17%, 0.38%, 0.34%, and 0.18% decreases in serum α-klotho concentrations. To what degree, these mild decreases in α-klotho are a matter of concern, is a subject ripe for discussion and additional investigations. When kidney function was normal or near normal but albuminuria was present, the associations between α-klotho and different metabolites of PAH were, more or less, randomly positive or negative and none reached statistical significance. To conclude, exposure to polycyclic aromatic hydrocarbons may result in reduced concentrations of α-klotho, an antiaging protein.

The Circulating Level of Klotho Is Not Dependent upon Physical Fitness and Age-Associated Methylation Increases at the Promoter Region of the Klotho Gene

(1) Background: Higher levels of physical fitness are believed to increase the physiological quality of life and impact the aging process with a wide range of adaptive mechanisms, including the regulation of the expression of the age-associated klotho (KL) gene and protein levels. (2) Methods: Here, we tested the relationship between the DNA methylation-based epigenetic biomarkers PhenoAge and GrimAge and methylation of the promoter region of the KL gene, the circulating level of KL, and the stage of physical fitness and grip force in two groups of volunteer subjects, trained (TRND) and sedentary (SED), aged between 37 and 85 years old. (3) Results: The circulating KL level is negatively associated with chronological age in the TRND group (r = -0.19; p = 0.0295) but not in the SED group (r = -0.065; p = 0.5925). The age-associated decrease in circulating KL is partly due to the increased methylation of the KL gene. In addition, higher plasma KL is significantly related to epigenetic age-deceleration in the TRND group, assessed by the biomarker of PhenoAge (r = -0.21; p = 0.0192). (4) Conclusions: The level of physical fitness, on the other hand, does not relate to circulating KL levels, nor to the rate of the methylation of the promoter region of the KL gene, only in males.

Hypertension and cardiomyopathy associated with chronic kidney disease: epidemiology, pathogenesis and treatment considerations

Chronic kidney disease (CKD) is a complex condition with a prevalence of 10-15% worldwide. An inverse-graded relationship exists between cardiovascular events and mortality with kidney function which is independent of age, sex, and other risk factors. The proportion of deaths due to heart failure and sudden cardiac death increase with progression of chronic kidney disease with relatively fewer deaths from atheromatous, vasculo-occlusive processes. This phenomenon can largely be explained by the increased prevalence of CKD-associated cardiomyopathy with worsening kidney function. The key features of CKD-associated cardiomyopathy are increased left ventricular mass and left ventricular hypertrophy, diastolic and systolic left ventricular dysfunction, and profound cardiac fibrosis on histology. While these features have predominantly been described in patients with advanced kidney disease on dialysis treatment, patients with only mild to moderate renal impairment already exhibit structural and functional changes consistent with CKD-associated cardiomyopathy. In this review we discuss the key drivers of CKD-associated cardiomyopathy and the key role of hypertension in its pathogenesis. We also evaluate existing, as well as developing therapies in the treatment of CKD-associated cardiomyopathy.

Aging-suppressor Klotho: Prospects in diagnostics and therapeutics

INTRODUCTION

The protein Klotho (KL) was first discovered in KL-deficient mice, which developed a syndrome similar to premature aging in humans. Since then, KL has been implicated in multiple molecular signaling pathways and diseases. KL has been shown to have anti-aging, healthspan and lifespan extending, cognitive enhancing, anti-oxidative, anti-inflammatory, and anti-tumor properties. KL levels decrease with age and in many diseases. Therefore, it has been of great interest to develop a KL-boosting or restoring drug, or to supplement endogenous Klotho with exogenous Klotho genetic material or recombinant Klotho protein, and to use KL levels in the body as a marker for the efficacy of such drugs and as a biomarker for the diagnosis and management of diseases.

OBJECTIVE

The goal of this study was to provide a comprehensive review of KL levels across age groups in individuals who are healthy or have certain health conditions, using four sources: blood, cerebrospinal fluid, urine, and whole biopsy/necropsy tissue. By doing so, baseline KL levels can be identified across the lifespan, in the absence or presence of disease. In turn, these findings can be used to guide the development of future KL-based therapeutics and biomarkers, which will heavily rely on an individual's baseline KL range to be efficacious.

METHODS

A total of 65 studies were collected primarily using the PubMed database. Research articles that were published up to April 2022 were included. Statistical analysis was conducted using RStudio.

RESULTS

Mean and median blood KL levels in healthy individuals, mean blood KL levels in individuals with renal conditions, and mean blood KL levels in individuals with metabolic or endocrine conditions were shown to decrease with age. Similarly, CSF KL levels in patients with AD also declined compared with age-matched controls.

CONCLUSIONS

The present study confirms the trend that KL levels in blood decrease with age in humans, among those who are healthy, and even further among those with renal and endocrine/metabolic illnesses. Further, by drawing this trend from multiple published works, we were able to provide a general idea of baseline KL ranges, specifically in blood in these populations. These data add to the current knowledge on normal KL levels in the body and how they change with time and in disease, and can potentially support efforts to create KL-based treatments and screening tools to better manage aging, renal, and metabolic/endocrine diseases.

Association between serum Klotho concentration and all-cause and cardiovascular mortality among American individuals with hypertension

BACKGROUND AND AIMS

Evidence indicates that serum Klotho concentration is associated with mortality in patients with chronic kidney disease (CKD). However, evidence on this association among people with hypertension is scarce. Therefore, we aimed to examine the association between serum Klotho concentration and all-cause and cardiovascular mortality in American patients with hypertension.

METHODS AND RESULTS

We included 6,778 participants with hypertension from the National Health and Nutrition Examination Survey (NHANES) 2007-2014. A Cox proportional hazard model was used to compute the hazard ratios (HRs) and 95% confidence intervals (CIs). The correlation between serum Klotho concentration and mortality was determined using restricted cubic spline and piecewise linear regression analyses. During 36,714 person-years of follow-up, 575 deaths were documented. Lower serum Klotho concentration was associated with increased all-cause mortality, but not cardiovascular mortality after multivariate adjustment. According to spline analysis, the correlation between serum Klotho concentration and all-cause mortality was non-linear (P < 0.001), and the threshold value was 574 pg/mL. The HR below the threshold point was 0.79 (95% CI: 0.67-0.93); no significant difference was found above the threshold point.

CONCLUSION

Higher serum Klotho concentration was associated with lower all-cause mortality, but not cardiovascular mortality in patients with hypertension with or without chronic renal impairment.

Advances in pathogenesis and treatment of essential hypertension

Hypertension is a significant risk factor for cardiovascular and cerebrovascular diseases and the leading cause of premature death worldwide. However, the pathogenesis of the hypertension, especially essential hypertension, is complex and requires in-depth studies. Recently, new findings about essential hypertension have emerged, and these may provide important theoretical bases and therapeutic tools to break through the existing bottleneck of essential hypertension. In this review, we demonstrated important advances in the different pathogenesis areas of essential hypertension, and highlighted new treatments proposed in these areas, hoping to provide insight for the prevention and treatment of the essential hypertension.

Associations between the concentrations of α-klotho and selected perfluoroalkyl substances in the presence of eGFR based kidney function and albuminuria: Data for US adults aged 40-79 years

Exposures to per- and polyfluoroalkyl substances (PFAS) cause oxidative stress, a risk factor for tissue damage leading to kidney and cardiovascular diseases. The antiaging protein klotho is known to act as an anti-oxidative agent, and how klotho homeostasis interacts with PFAS has not been reported. This study among 3981 US adults aged 40-79 years old evaluated relationships of internal PFAS contamination to α-klotho across stages of estimated glomerular filtration rate or eGFR-based kidney function and albuminuria defined as urinary albumin creatinine ratio of >30 mg/g creatinine. In the absence of albuminuria and when eGFR based kidney function was in stage GF-1 (eGFR ≥ 90 mL/min/1.73 m2), statistically significant inverse associations between α-klotho and PFNA (β = -0.04930, p < 0.01), PFDA (β = -0.03307, p = 0.02), and PFUnDA (β = -0.03451, p = 0.01), PFHxS (β = -0.03011, p = 0.04) and PFOS (β = -0.03126, p = 0.03) were noted. No associations between α-klotho and PFAS were observed when kidney function was in stages GF-2 (60 ≤ eGFR < 90 mL/min/1.73 m2) or GF-3A (45 ≤ eGFR < 60 mL/min/1.73 m2) in the presence or absence of albuminuria. Unexpectedly, however, in the absence of albuminuria, with kidney function in stage GF-3B/4 (15 ≤ eGFR < 45 mL/min/1.73 m2), associations were positive between α-klotho and PFOA (β = 0.20989, p < 0.01), PFNA (β = 0.18373, p < 0.1), PFDA (β = 0.20413, p < 0.01), PFUnDA (β = 0.17660, p < 0.01), and PFOS (β = 0.14267, p < 0.01). The inverse relationship of PFAS to the antioxidant protein α-klotho in those with healthy kidney function has not been previously reported and should be evaluated in other populations.

Phosphate intake, hyperphosphatemia, and kidney function

Phosphate is essential in living organisms and its blood levels are regulated by a complex network involving the kidneys, intestine, parathyroid glands, and the skeleton. The crosstalk between these organs is executed primarily by three hormones, calcitriol, parathyroid hormone, and fibroblast growth factor 23. Largely due to a higher intake of ultraprocessed foods, dietary phosphate intake has increased in the last decades. The average intake is now about twice the recommended dietary allowance. Studies investigating the side effect of chronic high dietary phosphate intake suffer from incomplete dietary phosphate assessment and, therefore, often make data interpretation difficult. Renal excretion is quickly adapted to acute and chronic phosphate intake. However, at the high ends of dietary intake, renal adaptation, even in pre-existing normal kidney function, apparently is not perfect. Experimental intervention studies suggest that chronic excess of dietary phosphate can result in sustained higher blood phosphate leading to hyperphosphatemia. Evidence exists that the price of the homeostatic response (phosphaturia in response to phosphate loading/hyperphosphatemia) is an increased risk for declining kidney function, partly due by intraluminal/tubular calcium phosphate particles that provoke renal inflammation. High dietary phosphate intake and hyperphosphatemia are progression factors for declining kidney function and are associated with higher cardiovascular disease and mortality risk. This is best established for pre-existing chronic kidney disease, but epidemiological and experimental data strongly suggest that this holds true for subjects with normal renal function as well. Here, we review the latest advances in phosphate intake and kidney function decline.

Serum klotho and its associations with blood and urine cadmium and lead across various stages of glomerular function: data for US adults aged 40-79 years

Exposures to cadmium and lead can cause oxidative stress, leading to tissue damage resulting in kidney and cardiovascular diseases. The antiaging protein klotho, on the other hand, is known to act as an anti-oxidative agent. How klotho homeostasis interacts with exposure to cadmium and lead has not been reported. Thus, this study was carried to investigate associations of serum klotho with blood and urine cadmium and lead in US adults aged 40-79 years across stages of eGFR-based kidney function and albuminuria defined as urinary albumin/creatinine ratio of > 30 mg/g creatinine. As long as the kidney function was normal (eGFR ≥ 90 mL/min/1.73 m²) or near normal (60 ≤ eGFR < 90 mL/min/1.73 m²), there was no evidence of an association between cadmium exposure and klotho concentrations irrespective of the presence/absence of albuminuria. During kidney dysfunction (15 ≤ eGFR < 60 mL/min/1.73 m²), 10% increases in blood cadmium concentrations resulted in decreases in klotho concentrations between 0.27 and 0.84%. In addition, during severe kidney dysfunction (15 ≤ eGFR < 45 mL/min/1.73 m²), a positive association between urine cadmium and serum klotho concentrations was observed. In the absence of albuminuria and when kidney function was normal or near normal, 10% increases in blood lead concentrations were observed to be associated with modest decreases between 0.28% and 0.37% in serum klotho concentrations. Similar results were observed between the concentrations of urine lead and serum klotho during kidney dysfunction.