Diabetes and other glucose metabolism abnormalities in Mexican Zapotec and Mixe Indians

AIMS

Aboriginal populations are experiencing an explosive rise in the prevalence of Type 2 diabetes. The purpose of this study was to estimate the prevalence of diabetes and other glucose metabolism abnormalities in Mexican Zapotec and Mixe Indians and to determine their association with known risk factors.

METHODS

A cross-sectional study was conducted in the southern Mexican state of Oaxaca. Two communities of Zapotec population and three of Mixe population were randomly chosen. Mexican Indians>or=35 years old were invited to participate; 394 Zapotec and 730 Mixe Indians participated. Diabetes and other glucose metabolism abnormalities were diagnosed using standard World Health Organization criteria after an oral glucose tolerance test. Prevalence and odds ratio (OR) were estimated with 95% confidence intervals (95% CI).

RESULTS

The crude prevalence of diabetes was 8.19% (95% CI 6.7-9.9%) and the age- and sex-adjusted prevalence was 8.27%, significantly higher among Zapotec (8.71%) than among Mixe Indians (6.90%). The prevalence of impaired glucose tolerance was 9.9% and 4.7% of the studied subjects had impaired fasting glucose. The main risk factors related to the occurrence of diabetes were a family history of diabetes (OR 4.1; 95% CI 1.9-8.8), obesity (OR 3.0; 95% CI 1.6-5.6), hypertension (OR 2.6; 95% CI 1.5-4.7) and a high-risk waist-hip ratio (4.6; 95% CI 1.2-17.7).

CONCLUSIONS

The prevalence of diabetes is high in this population, the highest so far reported in Mexican Indians. Mexico's health system faces a huge challenge to avert the advanced spread of diabetes in this susceptible population.

c/EBPbeta is a major regulatory element driving transcriptional activation of the CXCL12 promoter

CXCL12 is considered a constitutively expressed chemokine with homeostatic functions. However, induction of CXCL12 expression and its potential role in several pathologic conditions have been reported, suggesting that CXCL12 gene expression can be induced by different stimuli. To elucidate the molecular mechanisms involved in the regulation of CXCL12 gene expression, we aim to define the molecular factors that operate at the transcriptional level. Basal, constitutive expression of CXCL12 was dependent on basic helix-loop-helix factors. Transcriptional up-regulation of the CXCL12 gene was induced by cellular confluence or inflammatory stimuli such as interleukin-1 and interleukin-6, in a CCAAT/enhancer binding protein beta (c/EBPbeta)-dependent manner. Chromatin immunoprecipitation assays confirmed c/EBPbeta binding to a specific response element located at -1171 of the promoter region of CXCL12. Our data show that c/EBPbeta is a major regulatory element driving transcription of the CXCL12 gene in response to cytokines and cell confluence.

The structure of phage phi29 transcription regulator p4-DNA complex reveals an N-hook motif for DNA

Protein p4 affects the transcriptional switch that divides bacteriophage phi29 infection in early and late phases. The synthesis of DNA replication proteins and p4 takes place in the early phase, while structural, morphogenesis, and lysis proteins are synthesized in the late phase. Transcriptional switch by p4 is achieved by activating the late promoter A3 and repressing the early promoters A2b and A2c. The crystal structure of p4 alone and in complex with a 41 bp DNA, including the A3 promoter binding site, helps us to understand how the phage cycle is controlled. Protein p4 has a unique alpha/beta fold that includes a DNA recognition motif consisting of two N-terminal beta turn substructures, or N-hooks, located at the tips of an elongated protein homodimer. The two N-hooks enter the major groove of the double helix, establishing base-specific contacts. A high DNA curvature allows p4 N-hooks to reach two major groove areas three helical turns apart, like a bow and its string.