High levels of chemerin associated with variants in the NOS3 and APOB genes in rural populations of Ouro Preto, Minas Gerais, Brazil

Chemerin is an adipokine that has been associated with components of metabolic syndrome. It has been described to affect adipocyte metabolism and inflammatory responses in adipose tissue, as well as the systemic metabolism of lipids and glucose. Few epidemiological studies have evaluated classical and genetics cardiovascular risk factors (CVRFs) in the mixed adult rural population in Brazil. Therefore, the present study explored possible associations between CVRFs and chemerin. This cross-sectional study included 508 adults from the rural localities of Lavras Novas, Chapada, and Santo Antônio do Salto in Ouro Preto, Minas Gerais, Southeast Brazil. Demographic, behavioral, clinical, biochemical, anthropometric variables, and 12 single nucleotide polymorphisms (SNPs) linked with metabolic syndrome phenotypes were evaluated for associations with chemerin level. There was a significant association of high triglyceride levels [odds ratio (OR)=1.91, 95%CI: 1.23−2.98], insulin resistance (OR=1.82, 95%CI: 1.03−3.22), age (OR=1.64, 95%CI: 1.08−2.49), and sex (OR=1.99, 95%CI: 1.35−2.95) with high levels of chemerin. High chemerin levels were significantly associated with the genetic polymorphisms rs693 in the APOB gene (OR=1.50, 95%CI: 1.03−2.19) and rs1799983 in the NOS3 gene (OR=1.46, 95%CI: 1.01−2.12) for the AA and GT+TT genotypes, respectively. In the concomitant presence of genotypes AA of rs693 and GT+TT of rs1799983, the chance of presenting high levels of chemerin showed a 2.21-fold increase (95%CI: 1.25−3.88) compared to the reference genotype. The development of classical CVRFs in this population may be influenced by chemerin and by two risk genotypes characteristic of variants in well-studied genes for hypertension and dyslipidemia.

IGF2, LEPR, POMC, PPARG, and PPARGC1 gene variants are associated with obesity-related risk phenotypes in Brazilian children and adolescents

Association studies of genetic variants and obesity and/or obesity-related risk factors have yielded contradictory results. The aim of the present study was to determine the possible association of five single-nucleotide polymorphisms (SNPs) located in the IGF2, LEPR, POMC, PPARG, and PPARGC1 genes with obesity or obesity-related risk phenotypes. This case-control study assessed overweight (n=192) and normal-weight (n=211) children and adolescents. The SNPs were analyzed using minisequencing assays, and variables and genotype distributions between the groups were compared using one-way analysis of variance and Pearson's chi-square or Fisher's exact tests. Logistic regression analysis adjusted for age and gender was used to calculate the odds ratios (ORs) for selected phenotype risks in each group. No difference in SNP distribution was observed between groups. In children, POMC rs28932472(C) was associated with lower diastolic blood pressure (P=0.001), higher low-density lipoprotein (LDL) cholesterol (P=0.014), and higher risk in overweight children of altered total cholesterol (OR=7.35, P=0.006). In adolescents, IGF2 rs680(A) was associated with higher glucose (P=0.012) and higher risk in overweight adolescents for altered insulin (OR=10.08, P=0.005) and homeostasis model of insulin resistance (HOMA-IR) (OR=6.34, P=0.010). PPARG rs1801282(G) conferred a higher risk of altered insulin (OR=12.31, P=0.003), and HOMA-IR (OR=7.47, P=0.005) in overweight adolescents. PARGC1 rs8192678(A) was associated with higher triacylglycerols (P=0.005), and LEPR rs1137101(A) was marginally associated with higher LDL cholesterol (P=0.017). LEPR rs1137101(A) conferred higher risk for altered insulin, and HOMA-IR in overweight adolescents. The associations observed in this population suggested increased risk for cardiovascular diseases and/or type 2 diabetes later in life for individuals carrying these alleles.

Apolipoprotein E polymorphism in Brazilian dyslipidemic individuals: Ouro Preto study

The influence of apolipoprotein E alleles and genotypes on plasma lipid levels was determined in 185 individuals of mixed ethnicity living in Ouro Preto, Brazil. DNA was obtained from blood samples and the genotypes were determined by an RFLP-PCR procedure. The *3 allele was the most frequent (72 percent), followed by *4 (20 percent) and *2 (8 percent); *4 frequency was higher and *2 frequency was lower in the dyslipidemic group than in the normal control group. The *2 carriers presented lower LDL and total cholesterol levels compared to the *3 and *4 carriers. All six expected genotypes were observed in the individuals genotyped: E2/2 (2.1 percent), E4/4 (2.7 percent), E2/4 (3.7 percent), E2/3 (8.0 percent), E3/3 (53.3 percent), E3/4 (29.9 percent); no difference in genotype frequencies was found between the normal and dyslipidemic groups. Compared with *2, the presence of *3 increases more than two times the risk for dyslipidemia (OR = 2.31; P = 0.025; 95 percent CI = 1.06-5.06) and the presence of *4 increases it three times (OR = 3.31; P = 0.006; 95 percent CI = 1.36-8.04). The only significant effect of genotype was an increased risk for dyslipidemia in the *4 genotype carriers (E3/4 + E4/4) compared with the *2 genotype carriers (E2/2 + E2/3) with OR = 3.69 (95 percent CI = 1.25-10.88). The present study indicates that in the Ouro Preto admixed population the presence of APOE *2 can confer a protective effect, whereas the presence of APOE *4 implies an enhanced risk for dyslipidemia.

Kinetic characterization of rat tissue kallikrein using NÓ-substituted arginine 4-nitroanilides and NÓ-benzoyl-L-arginine ethyl ester as substrates

Hydrolysis of seven N(alpha-substituted L-arginine 4-nitroanilides: henzoyl-arginine p-nitroanilide (Bz-Arg-Nan), tosyl-arginine p-nitroanilide (Tos-Arg-Nan), acetyl-leucyl-arginine p-nitroanilide (Ac-Leu-Arg-Nan), acetyl-phenylalanyl-arginine p-nitroanilide (Ac-Phe-Arg-Nan), benzoyl-phenylalanyl-arginine p-nitroanilide (Bz-Phe-Arg-Nan), tosyl-phenylalanyl-arginine p-nitroanilide (Tos-Phe-Arg-Nan), and D-valyl-leucyl-arginine p-nitroanilide (D-Val-Leu-Arg-Nan), and the N(alpha-substituted L-arginine ester: benzoyl-arginine ethyl ester (Bz-Arg-OEt), by rat tissue kallikrein was studied throughout a wide range of substrate concentrations. The enzyme showed a bimodal behavior with all the substrates tested except Tos-Arg-Nan. At low substrate concentrations (10 to 170 muM for p-nitroanilides and 50 to 190 muM for Bz-Arg-OEt) the hydrolysis followed Michaelis-Menten kinetics, but at higher substrate concentrations (150 to 700 muM for p-nitroanilides and 200 to 1800 muM for Bz-Arg-OEt) a deviation from Michaelis-Menten kinetics was observed with a significant decrease in hydrolysis rates. At high concentrations of the p-nitroanilide substrates, partial enzyme inhibition was observed, whereas complete enzyme inhibition was observed with Bz-Arg-OEt at high concentration. The kinetic parameters reported here were calculated from data for substrate concentrations range where the enzyme followed Michaelis-Menten behavior. D-Val-Leu-Arg-Nan (Km = 24 ñ 2 muM; Vmax 10.42 ñ 0.28 muM/min) was the best substrate tested, followed by Ac-Phe-Arg-Nan (Km = 13 ñ 2 muM; Vmax = 3.21 ñ 0.11 muM/min), while Tos-Arg-Nan (Km = 29 ñ 2 muM; Vmax, = 0. 10 ñ 0.002 muM/min) was the worst of the tested substrates for rat tissue kallikrein. For the hydrolysis of Bz-Arg-OEt (Km = 125 ñ 15 muM; Vmax = 121.3 ñ 7.6 muM/min), the kinetic parameters using a substrate inhibition model can reasonably account for the observed enzyme behavior, with a Ksi value about 13.6 times larger than the estimated Km value.