Analysis of cytokine gene polymorphisms in Mestizo and native populations from Mexico

Interleukin-1 Alpha Polymorphisms Are Associated With Body Mass Index in Male But Not in Female Adolescents

BACKGROUND

The Interleukin (IL)-1 family of cytokines plays a key role in the inflammatory response. Genes coding for IL-1α, IL-1β, and IL-1Ra are located together as a block gene known as the IL-1 cluster. This genomic region shows wide nucleotide variability, and some polymorphisms have been widely studied and associated with features related to the metabolic syndrome.

METHODS

Eight polymorphisms within three genes of the IL-1 cluster, including IL1A (rs3783553, rs17561, and rs1800587), IL1B (rs1143634, rs1143627, and rs16944) and IL1RN (rs419598 and rs2234663) were genotyped in 460 Mexican adolescents. Genotype and haplotype frequencies are reported, as well as the linkage disequilibrium analysis. Genetic associations with some anthropometric and metabolic traits were evaluated.

RESULTS

Allele frequencies were similar to those found in other populations, and genotype proportions were according to the Hardy-Weinberg equilibrium. Seven haplotypes were observed at frequencies ≥5%. Of the entire cluster, only the rs17561-rs1800587 and rs1143627-rs16944 pairs showed highest and significant linkage disequilibrium values. An haplotype of IL1A, rs17561T-rs1800587T, was significantly associated with increase in body mass index in males (p <0.008), whereas IL1B and IL1RN variants showed associations with insulin, and hs-CRP (p <0.05).

CONCLUSIONS

Some MetS parameters seem to be influenced by variations in the IL-1 gene cluster in Mexican adolescents. These variations may confer risk for metabolic alterations from early ages, and and these risks may be different when variables such as sex are considered. Strategies leading to generate protective behaviors could be designed to take into account specific variations in the IL-1 gene cluster and biological conditions such as sex.

Intrauterine growth restriction and overweight, obesity, and stunting in adolescents of indigenous communities of Chiapas, Mexico

BACKGROUND/OBJECTIVES

Intrauterine growth restriction (IUGR) and low-birth-weight (LBW) are determinant factors in the development of metabolic diseases in children and adolescents. To estimate the magnitude of the association between LBW and IUGR with stunting or obesity among adolescents of two indigenous regions of the southern State of Chiapas, Mexico.

SUBJECTS/METHODS

We assessed a random sample of 303 adolescents selected from a birth cohort study (2003) conducted in three hospitals serving urban and rural communities of Tzotzil-Tzeltal and Selva regions of Chiapas, Mexico. Sociodemographic and anthropometric data from a sample of adolescents were correlated with their anthropometric data at birth (weight, length for age). Logistic regression models were fitted to estimate odds ratios (OR) with 95% confidence intervals to measure the magnitude of the association among the variables of interest. Models were adjusted for potential confounders.

RESULTS

In all, 12% of the sample had LBW and 28.8% IUGR. In total, 29% of adolescents were overweight/obese and 21% were stunted. We found a statistically significant association between IUGR and a lower risk of being overweight/obese. A higher probability for stunting was observed for LBW and IUGR.

CONCLUSIONS

Stunting and overweight/obesity prevalence in this population of adolescents was high and was associated with IUGR.

Apolipoprotein E4, Gender, Body Mass Index, Inflammation, Insulin Resistance, and Air Pollution Interactions: Recipe for Alzheimer's Disease Development in Mexico City Young Females

Given the epidemiological trends of increasing Alzheimer's disease (AD) and growing evidence that exposure and lifestyle factors contribute to AD risk and pathogenesis, attention should be paid to variables such as air pollution, in order to reduce rates of cognitive decline and dementia. Exposure to fine particulate matter (PM2.5) and ozone (O3) above the US EPA standards is associated with AD risk. Mexico City children experienced pre- and postnatal high exposures to PM2.5, O3, combustion-derived iron-rich nanoparticles, metals, polycyclic aromatic hydrocarbons, and endotoxins. Exposures are associated with early brain gene imbalance in oxidative stress, inflammation, innate and adaptive immune responses, along with epigenetic changes, accumulation of misfolded proteins, cognitive deficits, and brain structural and metabolic changes. The Apolipoprotein E (APOE) 4 allele, the most prevalent genetic risk for AD, plays a key role in the response to air pollution in young girls. APOE 4 heterozygous females with >75% to <94% BMI percentiles are at the highest risk of severe cognitive deficits (1.5-2 SD from average IQ). This review focused on the relationships between gender, BMI, systemic and neural inflammation, insulin resistance, hyperleptinemia, dyslipidemia, vascular risk factors, and central nervous system involvement in APOE4 urbanites exposed to PM2.5 and magnetite combustion-derived iron-rich nanoparticles that can reach the brain. APOE4 young female heterozygous carriers constitute a high-risk group for a fatal disease: AD. Multidisciplinary intervention strategies could be critical for prevention or amelioration of cognitive deficits and long-term AD progression in young individuals at high risk.