Association between serum alpha-Klotho and severe abdominal aortic calcification among civilians in the United States

A combined circulating microRNA panel predicts the risk of vascular calcification in community-dwelling older adults with age strata differences

BACKGROUND

Older adults have a higher risk of developing vascular calcification (VC). Circulating miRNAs can be potential risk indicators. However, prior studies used single miRNA mostly, whereas miRNA panels were rarely evaluated. We aimed to examine whether a miRNA panel outperformed each miRNA alone, and analyzed whether advanced age affected VC risk predictive performance offered by the miRNA panel.

METHODS

We prospectively enrolled older adults (age ≥65 years) during their annual health checkup in 2017, and examined their VC severity followed by analyzing sera for VC regulatory miRNAs (miR-125b-5p, miR-125b-3p, and miR-378a-3p). We used multiple regression analyses to determine associations between each miRNA or a 3-combind panel and VC risk, followed by area under the receiver-operating-characteristics curve (AUROC) analysis. Participants were further divided to those of 65-75 and ≥75 years for comparison.

RESULTS

From 199 older adults screened, 169 (median age, 73.3 years) with available calcification assessment were analyzed, among whom 74.6 % having VC. Those with VC had significantly lower circulating miR-125b-5p, miR-125b-3p, and miR-378a-3p levels than those without. Regression analyses showed that the 3-combined miRNA panel exhibited significant associations with VC risk, with significantly higher AUROC than those of models based on individual miRNA. Importantly, in those ≥75 years, the miRNA-predicted risk of VC was more prominent than that in the 65-75 years group.

CONCLUSION

A miRNA panel for VC risk prediction might outperform individual miRNA alone in older adults, and advanced age modified the association between circulating miRNAs and the risk of VC.

A cross-sectional study investigating the relationship between urinary albumin creatinine ratio and abdominal aortic calcification in adults

Introduction

The presence of abdominal aortic calcification (AAC) is strongly linked to the development of atherosclerosis and the incidence of morbidity and mortality related to cardiovascular diseases (CVD). Urinary albumin creatinine ratio (UACR) was found related with the increased risk of CVD. The aim of this study is to explore the relationship between the UACR and severe AAC (SAAC).

Methods and Results

This study included a total of 2,379 individuals aged over 40 years, and their information was obtained from the National Health and Nutrition Examination Survey conducted (NHANES) in 2013-2014. The measurement of AAC was conducted through dual-energy x-ray absorptiometry and assessed using the Kauppila scoring system. SAAC was characterized by a Kauppila score of 6 or higher. Multivariate regression models were used to analyze the relationship between UACR level and SAAC, with covariate adjustment. In the completely adapted model, the top third subgroup exhibits increased likelihood of SAAC (odds ratio 1.50; 95%CI: 0.98, 2.29; p = 0.030) in contrast to the bottom third subgroup. The subgroup analyses revealed a more pronounced correlation among the older participants (p-value for interaction = 0.013).

Discussion

In the United States, SAAC was more likely to occur in adults who had a higher probability of UACR. The use of UACR has the potential to be a valuable method for forecasting the likelihood of SAAC.

Association between dietary selenium intake and severe abdominal aortic calcification in the United States: a cross-sectional study

Abdominal aortic calcification (AAC) is an important predictor of cardiovascular disease. The purpose of the current study was to detect the association between dietary selenium intake and severe AAC. We included 2651 participants from the National Health and Nutrition Examination Survey (NHANES, 2013-2014). Dietary selenium intake was measured using the 24-hour recall method. AAC was quantified using the Kauppila score system based on dual-energy X-ray absorptiometry, with a score of >6 indicating severe AAC. The association between dietary selenium intake and severe AAC was analyzed by using a weighted multivariate logistic regression model, smooth curve fitting, and stratified subgroup analysis. After adjusting for multiple covariates, we found that higher dietary selenium intake was negatively associated with severe AAC incidence. When selenium intake was converted into tertiles, the highest tertile of dietary selenium intake was significantly associated with the incidence of severe AAC (odds ratio = 0.66). Smooth curve fitting revealed that this relationship was nonlinear. Subgroup analysis revealed that this negative association was present in participants with chronic kidney disease, but was absent when participants had hypertension or diabetes mellitus. Higher dietary selenium intake was negatively associated with severe AAC incidence in a nonlinear pattern, except in participants with diabetes mellitus or hypertension. However, further cohort studies are required to validate these findings.

Association between hemoglobin A1c and abdominal aortic calcification: results from the National Health and Nutrition Examination Survey 2013-2014

BACKGROUND

Hemoglobin A1c (HbA1c), a "gold standard" for the assessment of glycemic control, was associated with an increased risk of cardiovascular disease and coronary artery calcification. However, its effects on abdominal aortic calcification (AAC) are uncertain. The present study comprehensively investigated the association between HbA1c and AAC in the 2013-2014 National Health and Nutrition Examinations Surveys.

METHODS

Among 1,799 participants ≥ 40 years, dual-energy X-ray absorptiometry-derived AAC was quantified using the Kauppila score (AAC-24). Severe AAC was defined as a total AAC-24 > 6. Weighted linear regression models and logistic regression models were used to determine the effects of HbA1c on AAC. The restricted cubic spline model was used for the dose-response analysis.

RESULTS

The mean AAC-24 of participants was 1.3, and 6.7% of them suffered from severe AAC. Both AAC-24 and the prevalence of severe AAC increased with the higher tertile of HbA1c (P < 0.001). Elevated HbA1c levels would increase the AAC-24 (β = 0.73, 95% CI: 0.30-1.16) and the risk of severe AAC (OR = 1.63, 95% CI: 1.29-2.06), resulting in nearly linear dose-response relationships in all participants. However, this positive correlation were not statistically significant when participants with diabetes were excluded. Furthermore, subgroup analysis showed significant interactions effect between HbA1c and hypertension on severe AAC with the OR (95% CI) of 2.35 (1.62-3.40) for normotensives and 1.39 (1.09-1.79) for hypertensives (P for interaction = 0.022).

CONCLUSION

Controlling HbA1c could reduce AAC scores and the risk of severe AAC. Glycemic management might be a component of strategies for preventing AAC among all participants, especially normotensives.

Coffee consumption and abdominal aortic calcification among adults with and without hypertension, diabetes, and cardiovascular diseases

BACKGROUND AND AIMS

This study was performed to investigate the effect of coffee consumption on abdominal aortic calcification (AAC) among adults with and without hypertension, diabetes, and cardiovascular diseases (CVD).

METHODS AND RESULTS

A total of 2548 participants from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 were included. Coffee consumption was obtained from 24-h dietary recalls. Dual-energy X-ray absorptiometry (DXA) was used to measure the severity of AAC. In the fully adjusted model, compared with non-drinkers, high coffee consumption (≥390 g/d) was associated with higher AAC scores among participants with hypertension (β = 0.72, 95% CI: 0.21-1.22), diabetes (β = 1.20, 95% CI: 0.35-2.05), and CVD (β = 2.03, 95% CI: 0.71-3.36). We did not observe such an association among participants without hypertension, diabetes, and CVD. Furthermore, decaffeinated coffee was not associated with AAC.

CONCLUSION

In conclusion, patients with hypertension, diabetes, and CVD should focus on coffee consumption, especially caffeinated coffee, to reduce the burden of AAC.

A cross-sectional analysis of association between visceral adiposity index and serum anti-aging protein Klotho in adults

BACKGROUND

The visceral adiposity index (VAI) is regarded as a reliable indicator to assess body fat distribution and dysfunction. Klotho protein is a hormone with anti-aging biological functions. However, the relationship between them has not been researched.

OBJECTS

This study aimed to evaluate the association between VAI and serum anti-aging protein klotho in American adults.

METHODS

A cross-sectional study of participants was conducted based on the National Health and Nutrition Examination Surveys (NHANES) 2007-2016. Visceral adiposity was determined using the VAI score, while the klotho protein concentration was measured by ELISA kit. After adjusting some possible confounding variables, multivariate regression model was conducted to estimate the relationship between VAI and klotho protein. Furthermore, the smooth curve fitting and the segmented regression model were applied to examine the threshold effect and to calculate the inflection point.

RESULT

In total, 6 252 adults were eligible, with a mean VAI of 2.04 ± 0.03 and a mean klotho protein concentration of 848.79 ± 6.98 pg/ml. Multivariate regression analysis indicated that serum klotho protein concentration was lower in participants with high VAI score. When VAI was divided into quartiles, participants in the fourth quartiles of higher VAI had lower klotho protein levels (Q4: -32.25 pg/ml) than participants in the lowest quartile (Q1) after full adjustment (P < 0.05). Segmented regression suggested that the turning point value of VAI was 3.21. A 1-unit increase in VAI was significantly associated with lower klotho protein levels by -18.61 pg/ml (95% CI: -28.87, -8.35; P < 0.05) when VAI ranged from 0.29 to 3.21(accounting for 83.7% of the participants), however, the association was not significant when VAI ranged from 3.21 to 11.81 (P = 0.77).

CONCLUSION

There was a nonlinear correlation between VAI score and the serum anti-aging protein klotho concentrations, showing a saturation effect. When VAI was less than 3.21, they were negatively correlated, and when VAI was greater than 3.21, they had no obvious correlation.

The association between weight-adjusted-waist index and abdominal aortic calcification in adults aged ≥ 40 years: results from NHANES 2013-2014

The negative effects of obesity on the cardiovascular health have drawn much attention. Weight-adjusted-waist index (WWI) has been proved to reflect weight-independent centripetal obesity. However, the association between WWI and abdominal aortic calcification (AAC) has not been reported before. Using data from National Health and Nutrition Examination Survey 2013-2014, we aimed to determine the relationship of WWI and AAC in adults aged ≥ 40 years. WWI was determined by dividing waist circumference by the square root of weight. AAC was measured by dual-energy X-ray absorptiometry and quantified by Kauppila scores. Severe AAC (SAAC) was defined as an AAC score > 6. We utilized weighed multivariable logistic regression and generalized additive model to explore the independent association between WWI and AAC. Threshold effects were further calculated by two-piecewise linear regression model. 3082 participants were enrolled in our analysis, of which 48.2% were male. WWI was positively associated with AAC scores (β = 0.34, 95% CI 0.05-0.63) and exhibited a nonlinear relationship with SAAC. On the left of the breakpoint (WWI = 11.11), WWI and SAAC were positively associated (OR = 2.86, 95% CI 1.40-5.84), while no such relationship was found on the right (OR = 1.07, 95% CI 0.77-1.48). Our findings indicated that WWI may serve as a simple biomarker of AAC in US adults aged ≥ 40 years.

Association of serum klotho levels with different-staged vascular calcification status in patients with maintenance hemodialysis

Background

Vascular calcification (VC) is suggested to be associated with serum klotho levels in patients with maintenance hemodialysis (MHD), whereas there is a lack of reports on the associations of VC status in whole arteries with serum klotho contents.

Methods

One hundred forty eligible patients with MHD and a total of age-and gender-matched normal controls (NCs) were recruited. We analyzed the VC statuses of large arteries and peripheral muscular arteries by calculating the sum of scores from each artery. The levels of serum klotho were determined by ELISA. In addition, the relationship between serum klotho and VC status was evaluated using correlation analysis and regression analysis.

Results

The VC severity in MHD patients tended to be worse in comparison with NCs. Serum klotho level in patients with MHD was lower than that in the NC subjects (​P < 0.0001), which was correlated with VC scores as reflected by correlation analysis and regression analysis. Serum klotho concentrations exhibited a dynamic decline along with increased VC status stages. Subjects with higher levels of serum klotho had a higher prevalence of cardiovascular events.

Conclusion

Our study indicates serum klotho is strongly associated with VC status in a stage-dependent manner.

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.