The mutation of Trp64Arg in β3-adrenoreceptor-encoding gene is significantly associated with increased hypertension risk and elevated blood pressure: a meta-analysis

The Influence of FAM13A and PPAR-γ2 Gene Polymorphisms on the Metabolic State of Postmenopausal Women

Recently, we have observed two significant pandemics caused by communicable (COVID-19) and non-communicable factors (obesity). Obesity is related to a specific genetic background and characterized by immunogenetic features, such as low-grade systemic inflammation. The specific genetic variants include the presence of polymorphism of the Peroxisome Proliferator-Activated Receptors gene (PPAR-γ2; Pro12Ala, rs1801282, and C1431T, rs3856806 polymorphisms), β-adrenergic receptor gene (3β-AR; Trp64Arg, rs4994), and Family With Sequence Similarity 13 Member A gene (FAM13A; rs1903003, rs7671167, rs2869967). This study aimed to analyze the genetic background, body fat distribution, and hypertension risk in obese metabolically healthy postmenopausal women (n = 229, including 105 lean and 124 obese subjects). Each patient underwent anthropometric and genetic evaluations. The study has shown that the highest value of BMI was associated with visceral fat distribution. The analysis of particular genotypes has revealed no differences between lean and obese women except for FAM13A rs1903003 (CC), which was more prevalent in lean patients. The co-existence of the PPAR-γ2 C1431C variant with other FAM13A gene polymorphisms [rs1903003(TT) or rs7671167(TT), or rs2869967(CC)] was related to higher BMI values and visceral fat distribution (WHR > 0.85). The co-association of FAM13A rs1903003 (CC) and 3β-AR Trp64Arg was associated with higher values of systolic (SBP) and diastolic blood pressure (DBP). We conclude that the co-existence of FAM13A variants with C1413C polymorphism of the PPAR-γ2 gene is responsible for body fat amount and distribution.

Adrenergic receptors gene polymorphisms and autonomic nervous control of heart and vascular tone

Adrenergic receptors (ARs) are the primary targets of catecholamines released from the sympathetic nerve endings during their activation. ARs play a central role in autonomic nervous system and serve as important targets of widely used drugs. Several ARs gene polymorphisms were found to be associated with cardiovascular disease in previous clinical studies. Although more precise mechanism of the polymorphisms influence on autonomic control of cardiovascular system was studied in many previous physiological studies, their results are not unequivocal. This paper reviews the results of clinical and physiological studies focused on the impact of selected common single nucleotide polymorphisms of ARs genes involved in sympathetic control on cardiovascular system and its control. In summary, many studies assessed only a very limited range of cardiovascular control related parameters providing only very limited view on the complex cardiovascular control. The overview of partially contradicting results underlines a need to examine wider range of cardiovascular measures including their reactivity under various stress conditions requiring further study. It is expected that an effect of one given polymorphism is not very prominent, but it is suggested that even subtle differences in cardiovascular control could – on a longer time scale – lead to the development of severe pathological consequences.

Stratified meta-analysis by ethnicity revealed that ADRB3 Trp64Arg polymorphism was associated with coronary artery disease in Asians, but not in Caucasians

BACKGROUND

Previous studies demonstrated that ADRB3, beta-3 adrenergic receptor, participated in lipolysis and thermogenesis in adipose tissue. Consequently, this gene has attracted an increasing number of genetic studies examining its association with coronary artery disease (CAD) in different ethnicities in recent years, but no conclusion has been reached so far. The aim of this study was to explore whether the well-studied locus ADRB3 Trp64Arg in this gene confers a race-specific effect to CAD by conducting a stratified meta-analysis involving 15 independent studies and 11,802 subjects.

METHODS

Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of association. Publication bias was quantified and examined with Begg's funnel plot test and Egger's linear regression method. The overall meta-analysis or stratified meta-analysis by ethnicity was performed by using STATA 12.0 software.

RESULTS

A total of 15 eligible studies involving 5779 CAD cases and 6023 health controls were included in this meta-analysis. The pooled results indicated that ADRB3 Trp64Arg polymorphism was significantly associated with an increased risk of CAD. Further stratified analysis by ethnicity revealed that ADRB3 Trp64Arg polymorphism was significantly associated with CAD in Asians (allelic: OR = 1.48, 95%CI 1.13-1.94, P = .005; homozygous: OR = 2.66, 95%CI 1.87-3.77, P < .001; recessive: OR = 2.46, 95%CI 1.74-3.47, P < .001), but not in Caucasians (allelic: OR = 1.09, 95%CI 0.93-1.27, P = .290; homozygous: OR = 1.31, 95%CI 0.61-2.86, P = .490; recessive: OR = 1.31, 95%CI 0.60-2.84, P = 2.494).

CONCLUSIONS

This meta-analysis suggests that ADRB3 Trp64Arg polymorphism confers a race-specific effect to CAD.

Metabolic syndrome: an update on diagnostic criteria, pathogenesis, and genetic links

Metabolic syndrome (MetS), today a major global public health problem, is a cluster of clinical, metabolic, and biochemical abnormalities, such as central adiposity, hypertension, insulin resistance, and dyslipidemias. These MetS-related traits significantly increase the risk of type 2 diabetes mellitus, adverse cardiac events, stroke, and hepatic steatosis. The pathogenesis of MetS is multifactorial, with the interplay of environmental, nutritional, and genetic factors. Chronic low-grade inflammation together with visceral adipose tissue, adipocyte dysfunction, and insulin resistance plays a major role in the progression of the syndrome by impairing lipid and glucose homeostasis in insulin-sensitive tissues, such as the liver, muscle, and adipocytes. Adipose-derived inflammatory cytokines and non-esterified fatty acids establish the link between central obesity IR, inflammation, and atherogenesis. Various studies have reported an association between MetS and related traits with single-nucleotide polymorphisms of different susceptibility genes. Modulation of cytokine levels, pro-oxidants, and disturbed energy homeostasis, in relation to the genetic variations, is described in this review of the recent literature, which also provides updated data regarding the epidemiology, diagnostic criteria, and pathogenesis of MetS.

ADRB3 polymorphism rs4994 (Trp64Arg) associates significantly with bodyweight elevation and dyslipidaemias in Saudis but not rs1801253 (Arg389Gly) polymorphism in ARDB1

Background

In some populations, obesity and body weight related disorders show a correlation with polymorphisms in three subtypes of beta-adrenoceptor (β1, β2, and β3) [ADRB1, ADRB2 and ADRB3] genes. We scanned for the polymorphism of Arg389Gly (rs1801253) in ADRB1 and Trp64Arg (rs4994) in ADRB3 genes in Saudi population to determine association, if any, of these polymorphisms with obesity and related disorders.

Methods

We studied 329 non-related adults (33.1% men and 66.9% women), aged 18–36 years. Anthropometric measurements were recorded, and Body mass index (BMI) and waist/hip ratio were calculated; leptin, insulin, lipidogram, and glucose concentrations were determined. ADRB1 and ADRB3 polymorphisms (Arg389Gly and Trp64Arg, respectively) were screened by DNA sequencing. The subjects were divided into three groups according to BMI: normal weight (BMI < 25 kg/m²), overweight (BMI ≥25.1–29.9 kg/m²) subjects, and obese (≥30 kg/m²).

Results

In the age-matched groups of the normal weight, overweight and obese male and female subjects, all anthropometric parameters were found to be significantly higher, and in the obese group, all biochemical parameters were significantly elevated compared to the normal weight controls. The allelic frequency of Gly389 ADRB1 did not differ amongst the three groups, whereas the frequency of Arg64 of ADRB3 gene was significantly higher in the overweight and obese subjects, compared with the normal weight subjects. In addition, subjects carrying Arg64 allele regardless of their BMI had a greater waist and hip circumference, W/H ratio, plasma cholesterol, triglyceride, LDL, leptin, insulin, and glucose level compared to those with the wild-type Trp allele.

Conclusion

The results of this study have shown a significant association between the Trp64Arg polymorphism in ADRB3 gene and the development of overweight and obesity in Saudi populations. It also has an influence on the levels of lipid, insulin, leptin, and glucose, whereas, Arg389Gly polymorphism in ADRB1 is not associated with overweight, obesity or dyslipidaemias in Saudis.