[From genotype to phenotype: amylase gene in childhood obesity]. / Del genotipo al fenotipo: gen de la amilasa en obesidad infantil.

Worldwide, Mexico is one of the countries with the highest rate of obesity, which is a condition considered the main risk factor for type 2 diabetes. Among the mechanisms that predispose to obesity, the interaction between food intake and genetic components has been little explored. Recently we evidenced a significant association between the copy number (CN) of AMY1A and AMY2A genes, the enzymatic activity of salivary and pancreatic amylase, and the frequency of childhood obesity in Mexico, a particular population due to the high consumption of starch in the diet and the high prevalence of obesity in children and adults. This review aims to find a better understanding of the role of amylase in obesity through a description of the evolution of the CN of its genes, the association of its enzymatic activity with obesity, and the effect of its interaction with starch intake on Mexican children. In addition, it denotes the importance of the experimental perspectives of further investigation regarding the mechanism by which amylase could regulate the abundance of oligosaccharide-fermenting bacteria and producers of short-chain fatty acids and/or branched-chain amino acids that could contribute to the alteration of the physiological processes associated with intestinal inflammation and metabolic deregulation that predispose to the development of obesity.

A nivel mundial, México es uno de los países con la tasa más alta de obesidad, un padecimiento considerado como el principal factor de riesgo de diabetes tipo 2. Dentro de los mecanismos que predisponen a la obesidad, la interacción entre la ingesta alimentaria y el componente genético ha sido poco explorada. Recientemente evidenciamos la asociación del número de copias (NC) de los genes AMY1A y AMY2A, y la actividad enzimática de amilasa salival y pancreática con la frecuencia de obesidad infantil en México, una población que se caracteriza por presentar alto consumo de almidón en la dieta y alta prevalencia de obesidad. La presente revisión busca conseguir un mejor entendimiento del papel de la amilasa en la obesidad por medio de una descripción de la evolución del NC de sus genes, la asociación de su actividad enzimática con la obesidad y el efecto de su interacción con la ingesta de almidón en niños mexicanos. Además, refiere las perspectivas experimentales que permitirían profundizar en la investigación del mecanismo por el cual la amilasa podría regular la abundancia de bacterias fermentadoras de oligosacáridos y productoras de ácidos grasos de cadena corta o aminoácidos de cadena ramificada que podrían contribuir con la alteración de los procesos fisiológicos asociados con la inflamación intestinal y la desregulación metabólica que predispone al desarrollo de obesidad.

Type 2 diabetes-associated polymorphisms correlate with SIRT1 and TGF-ß1 gene expression.

The polymorphisms rs3758391 and rs1800470 located in SIRT1 and TGF-ß1 have been associated with type 2 diabetes in different populations but its functional effect is not clear. In this study, we evaluated their effect on the expression of SIRT1 and TGF-ß1 in peripheral blood as well as their participation in the formation of DNA-protein complexes in a pancreas-derived cell line. It has been described that SIRT1 and TGF-ß1 participate in cell growth and regulation of production and secretion of insulin in the pancreas. Anthropometric and biochemical profiles of 127 adults were measured. Genotypes for rs3758391 and rs1800470 were determined using TaqMan assays. Expression analysis of SIRT1 and TGF-ß1 were performed using real-time PCR. Gene expression of these genes increased 1.8 ± 0.6- and 1.3 ± 0.6-fold in patients carrying the TT genotype of rs3758391 and rs1800470 when compared to carriers of the CC genotype. Then, we tested whether these single-nucleotide polymorphisms (SNPs) (and rs932658, which is in linkage disequilibrium with rs3758391) are located in regulatory DNA-protein binding sites by electrophoretic mobility shift assays using nuclear extract from the pancreas-derived cell line BxPC-3. The electrophoretic mobility shift assay showed no binding of nuclear proteins to DNA. In conclusion, the genotypes of rs3758391 and rs1800470 are associated with modifications in the expression of the genes SIRT1 and TGF-ß1, respectively, but none of the tested SNPs are located in regulatory DNA-protein binding sites.

Altered Glycemic Control Associated With Polymorphisms in the SLC22A1 (OCT1) Gene in a Mexican Population With Type 2 Diabetes Mellitus Treated With Metformin: A Cohort Study.

The organic cation transporters OCT1 and OCT2 and the multidrug and toxin extrusion transporter MATE1, encoded by the SLC22A1, SLC22A2, and SLC47A1 genes, respectively, are responsible for the absorption of metformin in enterocytes, hepatocytes, and kidney cells. The aim of this study was to evaluate whether genetic variations in the SLC22A1, SLC22A2, and SLC47A1 genes could be associated with an altered response to metformin in patients with type 2 diabetes mellitus. A cohort study was conducted in 308 individuals with a diagnosis of type 2 diabetes mellitus of less than 3 years and who had metformin monotherapy. Three measurements of blood glycated hemoglobin (HbA1c ) were obtained at the beginning of the study and after 6 and 12 months. Five polymorphisms were analyzed in the SLC22A1 (rs622342, rs628031, rs594709), SLC22A2 (rs316019), and SLC47A1 (rs2289669) genes by real-time polymerase chain reaction. The results showed a significant association among genotypes CC-rs622342 (ß = 1.36; P < .001), AA-rs628031 (ß = 0.98; P = .032), and GG-rs594709 (ß = 1.21; P = .016) in the SLC22A1 gene with an increase in HbA1c levels during the follow-up period. Additionally, a significant association was found in the CGA and CAG haplotypes with an increase in HbA1c levels compared to the highest-frequency haplotype (AGA). In conclusion, the genetic variation in the SLC22A1 gene was significantly related to the variation of the HbA1c levels, an important indicator of glycemic control in diabetic patients. This information may contribute to identifying patients with an altered response to metformin before starting their therapy.