Association of Klotho gene polymorphism with hypertension and coronary artery disease in an Iranian population

Effects of flaxseed supplementation on weight loss, lipid profiles, glucose, and high-sensitivity C-reactive protein in patients with coronary artery disease: A systematic review and meta-analysis of randomized controlled trials

This meta-analysis aimed to evaluate the effects of flaxseed supplementation on weight loss, lipid profiles, high-sensitivity C-reactive protein (hs-CRP), and glucose levels in patients with coronary artery disease (CAD). A systematic search was performed using various online databases, including Scopus, PubMed, Web of Science, EMBASE, and Cochrane Library, to identify relevant randomized controlled trials (RCTs) until June 2023. To evaluate heterogeneity among the selected studies, the Q-test and I2 statistics were employed. Data were combined using either a fixed- or random-effects model and presented as a weighted mean difference (WMD) with a 95% confidence interval (CI). Of the 428 citations, six RCTs were included. The pooled results did not show significant changes in the WMD of lipid factors (high-density lipoprotein cholesterol, triglycerides (TG), low-density lipoprotein cholesterol, and total cholesterol) following flaxseed intake. However, after performing a sensitivity analysis to determine the source of heterogeneity, flaxseed supplementation resulted in a significant decrease in TG levels (WMD = -18.39 mg/dL; 95% CI: -35.02, -1.75). Moreover, no significant differences were observed in either weight or BMI following flaxseed intake. However, the circulating levels of fasting blood glucose (WMD = -8.35 mg/dL; 95% CI: -15.01, -1.69, p = .01) and hs-CRP (WMD = -1.35 mg/L; 95% CI: -1.93, -0.77, p < .01) significantly decreased after the intervention. Flaxseed supplementation was associated with lowering FBS, hs-CRP, and TG levels but did not affect weight loss parameters and other lipid markers in CAD.

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.

A study of the molecular mechanism of quercetin and dasatinib combination as senolytic in alleviating age-related and kidney diseases

Aging is a significant risk factor for the majority of prevalent human illnesses. The chance of having severe chronic conditions grows dramatically with advancing age. Indeed, more than 90% of people over 65 get at least one chronic disease, including diabetes, heart disease, malignancy, memory loss, and kidney disease, whereas more than 70% have two or more of these ailments. Mouse and human aging lead to increased senescent cells and decreased klotho concentrations. Mice lacking the protein α-klotho show faster aging, similar to human aging. α-Klotho upregulation extends life and slows or suppresses the onset of many age-related illnesses and kidney diseases. Like the consequences of α-klotho deficiency, senescent cell accumulation is linked to tissue dysfunction in various organs and multiple age-related kidney diseases. In addition, α-klotho and cell senescence are negatively and presumably mechanistically linked. Earlier research has demonstrated that klotho exerts its protective effects in age-related and kidney disease by interacting with Wnt ligands, serving as an endogenous antagonist of Wnt/β-catenin signaling. In addition, decreasing senescent cell burden with senolytics, a class of drugs that remove senescent cells selectively and extend the life span of mice. In this work, we are studying the molecular mechanism of the combination of quercetin and dasatinib as senolytic in easing age-related chronic renal illness by altering the level of klotho/Wnt/β-catenin. PRACTICAL APPLICATIONS: There is an inverse relationship between the onset and the development of age-related disorders and cellular senescence and Klotho. Earlier attempts to suppress transforming growth factor-beta 1 (TGF-β1) in kidney disease with anti-TGF-β1 antibodies were ineffective, and this should be kept in mind. Senolytic medications may benefit from targeting senescent cells, which enhances the protective factor α-klotho. In addition, our study provides a unique, translationally feasible route for creating orally active small compounds to enhance α-klotho, which may also be a valuable biomarker for age-related kidney disease. Additionally, other aspects of aging can be affected by senolytics, such as limiting age-related mitochondrial dysfunction, lowering inflammation and fibrosis, blunting reactive oxygen species (ROS) generation, decreasing deoxyribonucleic acid (DNA) damage, and reinforcing insulin sensitivity. Senolytic agents have been shown to increase adipose progenitor and cardiac progenitor cell activity in aging animals and animals with cellular senescence-related diseases, such as heart, brain, and kidney disease.

Investigation of Klotho G395A and C1818T Polymorphisms and Their Association with Serum Glucose Level and Risk of Type 2 Diabetes Mellitus

Objective: The objective was to study the association of Klotho gene G395A and C1818T single nucleotide polymorphisms with glycemia, serum, glycosylated hemoglobin (HbA1c) level and the risk of type 2 diabetes mellitus (T2DM) in the Pashtun population of Pakistan. Methods: In this study, 195 normal individuals and 217 T2DM patients were enrolled. All subjects were divided into three groups, namely overall subjects (control + T2DM patients), control individuals and T2DM patients, and their fasting glucose, HbA1c level, lipid profile and C1818T and G395A polymorphisms were determined. Results: The allele frequencies of G395A in overall subjects were 0.568 for A and 0.432 for G. Similarly, allele frequencies for G395A in overall subjects were 0.597 and 0.403 for C and T alleles, respectively. The AA genotype of G395A was observed to be a risk factor for T2DM. In normal individuals, no significant (p > 0.05) association was observed between klotho C1818T and G395A polymorphisms and hyperglycemia. In overall subjects, the C1818T polymorphism was associated (p < 0.05) with high fasting glucose and HbA1c levels in female subjects only. In T2DM patients, both C1818T and G395A polymorphisms were found to be significantly (p < 0.05) associated with high fasting glucose and HbA1c levels both in males and females. Conclusion: The G395A polymorphism was observed to increase the risk of T2DM. Both C1818T and G395 were associated with high fasting glucose and HbA1c levels in T2DM patients.

Apelin and its ratio to lipid factors are associated with cardiovascular diseases: A systematic review and meta-analysis

Background

The present systematic review and meta-analysis aimed to ascertain if the circulating levels of apelin, as an important regulator of the cardiovascular homeostasis, differ in patients with cardiovascular diseases (CVDs) and controls.

Methods

A comprehensive search was performed in electronic databases including PubMed, Scopus, EMBASE, and Web of Science to identify the studies addressing apelin in CVD up to April 5, 2021. Due to the presence of different units to measure the circulating levels of apelin across the included studies, they expressed the standardized mean difference (SMD) and their 95% confidence interval (CI) as summary effect size. A random-effects model comprising DerSimonian and Laird method was used to pool SMDs.

Results

Twenty-four articles (30 studies) comprised of 1793 cases and 1416 controls were included. Pooled results obtained through random-effects model indicated that apelin concentrations in the cases’ blood samples were significantly lower than those of the control groups (SMD = -0.72, 95% CI: -1.25, -0.18, P = 0.009; I2 = 97.3%, P<0.001). New combined biomarkers showed a significant decrease in SMD of apelin/high-density lipoprotein cholesterol (apelin/HDL-C) ratio [-5.17; 95% CI, -8.72, -1.63, P = 0.000; I2 = 99.0%], apelin/low-density lipoprotein cholesterol (apelin/LDL-C) ratio [-4.31; 95% CI, -6.08, -2.55, P = 0.000; I2 = 98.0%] and apelin/total cholesterol (apelin/TC) ratio [-17.30; 95% CI, -22.85, -11.76, P = 0.000; I2 = 99.1%]. However, no significant differences were found in the SMD of apelin/triacylglycerol (apelin/TG) ratio in cases with CVDs compared to the control group [-2.96; 95% CI, -7.41, 1.49, P = 0.000; I2 = 99.2%].

Conclusion

The association of apelin with CVDs is different based on the region and disease subtypes. These findings account for the possible usefulness of apelin as an additional biomarker in the diagnosis of CVD in diabetic patients and in the diagnosis of patients with CAD. Moreover, apelin/HDL-c, apelin/LDL-c, and apelin/TC ratios could be offered as diagnostic markers for CVD.

S-Klotho level and physiological markers of cardiometabolic risk in healthy adult men

S-Klotho is perceived as a biomarker of healthy aging that has been shown to be inversely associated with cardiometabolic risk in elderly individuals. The aim of this study was to test if s-Klotho level is associated with cardiometabolic risk markers in younger healthy men in order to verify the possible role of s-Klotho level as an early marker of cardiometabolic risk. A cross-sectional study was conducted among 186 healthy men (M_age=35.33, SD_age=3.47) from a Western urban population. Serum basal levels of s-Klotho, lipid profile, homocysteine, glycemia markers, C-reactive protein, liver transaminases and creatinine were evaluated. Also, blood pressure was measured and cardiometabolic risk score and homeostatic model assessment for insulin resistance (HOMA-IR) were calculated. Testosterone and cortisol levels, self-reported psychological stress, physical activity, smoking in the past, alcohol use and body adiposity were controlled for. We found no relationship between levels of s-Klotho and physiological markers of cardiometabolic risk in the studied population. The results were similar when controlled for adiposity, testosterone level, physical activity, alcohol use and smoking in the past. We suggest that s-Klotho level is not an early marker of cardiometabolic risk in younger middle-aged healthy men.

MIF rs755622 and IL6 rs1800795 Are Implied in Genetic Susceptibility to End-Stage Renal Disease (ESRD)

Chronic kidney disease (CKD) is characterized by an increased risk of kidney failure and end-stage renal disease (ESRD). Aging and comorbidities as cardiovascular diseases, metabolic disorders, infectious diseases, or tumors, might increase the risk of dialysis. In addition, genetic susceptibility factors might modulate kidney damage evolution. We have analyzed, in a group of ESRD patients and matched controls, a set of SNPs of genes (Klotho rs577912, rs564481, rs9536314; FGF23 rs7955866; IGF1 rs35767; TNFA rs1800629; IL6 rs1800795; MIF rs755622, rs1007888) chosen in relation to their possible involvement with renal disease and concomitant pathologies. Analysis of the raw data did indicate that IL6 rs180795 and MIF rs755622 SNPs might be markers of genetic susceptibility to ESRD. In particular, the C positive genotypes of MIF rs755622, (dominant model) seem to be an independent risk factor for ESDR patients (data adjusted for age, gender, and associated pathologies). Stratifying results according to age MIF rs755622 C positive genotype frequencies are increased in both the two age classes considered (<59 and ≥59-year-old subjects). Analyses of data according to gender allowed us to observe that ESRD women shoved a significantly reduced frequency of genotypes bearing IL6 rs180795 C allele. In addition, MIF rs755622 might interact with diabetes or hypercholesterolemia in increasing susceptibility to ESRD. In conclusion, our data indicate that some polymorphisms involved in the regulation of both renal function and inflammatory response can influence the evolution of chronic kidney disease and suggest that the modulation of the activities of these and other genes should also be considered as therapeutic targets on to intervene with innovative therapies.

Role of Klotho in the Development of Essential Hypertension

Klotho has antiaging properties, and serum levels decrease with physiological aging and aging-related diseases, such as hypertension, cardiovascular, and chronic kidney disease. Klotho deficiency in mice results in accelerated aging and cardiovascular injury, whereas Klotho supplementation slows down the progression of aging-related diseases. The pleiotropic functions of Klotho include, but are not limited to, inhibition of insulin/IGF-1 (insulin-like growth factor 1) and WNT (wingless-related integration site) signaling pathways, suppression of oxidative stress and aldosterone secretion, regulation of calcium-phosphate homeostasis, and modulation of autophagy with inhibition of apoptosis, fibrosis, and cell senescence. Accumulating evidence shows an interconnection between Klotho deficiency and hypertension, and Klotho gene polymorphisms are associated with hypertension in humans. In this review, we critically review the current understanding of the role of Klotho in the development of essential hypertension and the most important underlying pathways involved, such as the FGF23 (fibroblast growth factor 23)/Klotho axis, aldosterone, Wnt5a/RhoA, and SIRT1 (Sirtuin1). Based on this critical review, we suggest avenues for further research.

No significant association of serum klotho concentration with blood pressure and pulse wave velocity in a Chinese population

Klotho, an important anti-aging protein, may be related to elevated blood pressure (BP) and arterial stiffness. We aimed to investigate associations between the serum klotho concentration and peripheral/central BP and arterial stiffness based on the carotid–femoral pulse wave velocity (cfPWV) in a Chinese population. We invited all inhabitants aged ≥ 18 years in two Dali communities for participation. The SphygmoCor system was used to record radial arterial waveforms. Aortic waveforms were derived using a generalized transfer function. The central BP was assessed by calibrating the brachial BP, which was measured using an oscillometric device. The serum klotho concentration was measured using an enzyme-linked immunosorbent assay and logarithmically transformed. Of the 716 participants (mean age: 51.9 ± 12.6 years), 467 (65.2%) were women. The median serum klotho concentration was 381.8 pg/mL. The serum klotho concentration did not significantly differ between patients with and without hypertension (P > 0.05) and between those with and without arterial stiffness (cfPWV ≥ 10 m/s) (P > 0.05). After adjusting for confounders, the serum klotho concentration was not significantly associated with the peripheral or central BP (P > 0.05) and cfPWV (P > 0.05). Our data indicated that the serum klotho concentration was not associated with BP or cfPWV in the general Chinese population.

KLOTHO polymorphisms and age-related outcomes in community-dwelling older subjects: The São Paulo Ageing & Health (SPAH) Study

Defective KLOTHO gene expression in mice led to a syndrome resembling human ageing. This study evaluated three KLOTHO polymorphisms, namely G395A, C1818T, and C370S, in an elderly population (mean age of 73 years) and their associations with ageing-related outcomes (cardiovascular events, kidney function, osteoporosis, sarcopenia) and mortality. Estimated glomerular filtration rates (eGFR) was lower in subjects with 1818TT (P = 0.047) and 370SS (P = 0.046) genotypes. The 1818TT genotype (P = 0.006) and 1818T allele were associated with higher frequency of myocardial infarction (MI) (CC:1.7% vs. CT + TT:7.0%; P = 0.002). The 370SS genotype was associated with lower stroke frequency (P = 0.001). MI (OR 3.35 [95% CI: 1.29–8.74]) and stroke (OR 3.64 [95% CI: 1.48–8.97]) were associated with mortality. Regarding MI, logistic regression showed 1818T allele was a risk factor for death-related MI (OR 4.29 [95% CI: 1.60–11.52]; P = 0.003), while 370C was protective (OR 0.03 [95% CI: 0.01–0.08]; P < 0.001). Regarding stroke, the 395A and 370C alleles were protective factors (respectively: OR 0.28 [95% CI: 0.20–0.80]; P = 0.018; OR 0.10 [95% CI: 0.05–0.18]; P < 0.001). This is the first study to determine potential associations between common ageing-related outcomes/mortality and KLOTHO polymorphisms. The 1818T allele was a risk factor for MI-related death. The 395A and 370C alleles were protective factors for stroke-related death in elderly from community.

KLB gene polymorphism is associated with obesity and non-alcoholic fatty liver disease in the Han Chinese

Klotho beta (KLB) mediates binding of fibroblast growth factor (FGF) 21 to the FGF receptor (FGFR). FGF21-KLB-FGFR signaling regulates multiple metabolic systems in the liver, and we hypothesized that FGF21, KLB and FGFR single-nucleotide polymorphisms (SNPs) are involved in hepatic lipid accumulation. The SNPs were detected in 1688 individuals divided into four groups: non-obese without non-alcoholic fatty liver disease (NAFLD), obese without NAFLD, non-obese with NAFLD, and obese with NAFLD. The A-allele of KLB SNP rs7670903 correlated with higher body mass index (P = 0.0005), and the A-allele frequency was higher in the obese than non-obese group (P = 0.003). The G-allele frequency of KLB rs7674434 and T-allele frequency of rs12152703 were higher in the obese with NAFLD than obese without NAFLD group (P = 0.004 and P = 0.006), but the genotype distribution between two non-obese groups did not differ. KLB rs7674434 and rs12152703 had associations with alanine aminotransferase (ALT) (P = 0.03 and P = 0.04, respectively) and gamma-glutamyltransferase (P = 0.03 and P = 0.02, respectively) levels in all subjects, but the associations were especially strong with ALT in the NAFLD group (P = 0.005 and P = 0.008, respectively). These findings suggest that KLB SNPs are related to obesity and hepatic inflammation and that they may be involved in the pathogenesis of NAFLD.

CD36 gene polymorphism rs1761667 (G > A) is associated with hypertension and coronary artery disease in an Iranian population

Background

CD36 is associated with regulation of lipid metabolism, atherosclerosis, and blood pressure. Moreover, its variation may be involved in the development of hypertension and/or coronary artery disease (CAD). The present study was conducted to investigate the possible association of CD36 rs1761667 (G > A) polymorphism with hypertension and/or CAD in the southeastern of Iran.

Methods

The present observational study was composed of 238 subjects who were admitted for coronary angiography, and divided into four groups: 1) hypertensive without CAD (H-Tens, n = 52); 2) hypertensive with CAD (CAD + H-Tens, n = 57); 3) CAD without hypertension (CAD, n = 65); and 4) non-hypertensive without CAD as the control group (Ctrl, n = 64). The CD36 rs1761667 polymorphism was genotyped with PCR-RFLP method. Association between CD36 rs1761667 genotypes and the risk of CAD and hypertension was assessed using multinomial regression by adjusting for age, sex, creatinine, fasting blood sugar (FBS), systolic blood pressure (SBP) and diastolic blood pressure (DBP).

Results

In the present study, minor allele (A) frequency was 0.36. The genotype, but not allele frequency of the CD36 rs1761667 was significantly different between the four study groups (p = 0.003). Furthermore, using a recessive inheritance model CD36 rs1761667 polymorphism was significantly associated with an increased risk of CAD with hypertension (OR = 5.677; 95% CI = 1.053–30.601; p = 0.043). However, using the dominant model of CD36 rs1761667 had a protective effect on H-Tens and CAD patients.

Conclusion

The present findings revealed an association between CD36 rs1761667 polymorphism and susceptibility to hypertension and/or CAD in a southeastern Iranian population.