Circulatory miRNA biomarkers of metabolic syndrome.

AIMS: Circulatory microRNAs (c-miRNAs) exert important roles in the molecular dysregulation of cardio-metabolic diseases. However, little is known whether dysregulated miRNA expression occurs when risk factors are elevated, as in the metabolic syndrome (MetS). This study quantified c-miRNA expression in individuals with MetS compared to healthy, further examining the relationship of gene pathways with the underlying pathogenesis. METHODS: Expression of 26 miRNAs was quantified in plasma from 40 women (20 healthy and 20 MetS) and 39 men (20 healthy and 19 MetS) by qPCR. In silico analysis was performed to investigate biological effects of the dysregulated miRNAs. Dysregulated miRNA expression was further validated in an independent cohort of 20 women (10 healthy and 10 MetS). RESULTS: Regression model adjusted for age and sex identified miR-15a-5p, miR-17-5p, miR-370-3p and miR-375 as important predictors of MetS presence. Analysis of predictive miRNAs in the validation cohort strengthened the relationship with miR-15a-5p and miR-17-5p expression. These miRNAs share genes involved in the regulation of metabolic pathways including insulin, wnt, fatty acid metabolism and AMPK. CONCLUSIONS: miR-15a-5p and miR-17-5p were identified as predictive biomarkers of MetS, irrespective of sexes, further demonstrating the relationship of c-miRNAs to known pathways of metabolic disturbances present in cardio-metabolic diseases.

Effect of PM(10) and O(3) on infant mortality among residents in the Mexico City Metropolitan Area: a case-crossover analysis, 1997-2005.

INTRODUCTION: Consistent evidence has shown a positive association between air pollution and daily mortality among adults. Less is known about its effect on infant mortality and the modification of this association by socioeconomic status (SES). OBJECTIVE: To assess the association of particulate matter with an aerodynamic diameter of ≤10µm (PM(10)) and ozone (O(3)) on infant mortality and its modification by SES. METHODS: We evaluated the relationship of 24 h mean PM(10) and 1h daily maximum O(3) levels with 12 079 all-cause deaths (3903 respiratory deaths) among 1- to 11-month-old infants residing in the Mexico City Metropolitan Area between January 1997 and December 2005 using a case-crossover approach. The data were analysed using conditional logistic regression models, controlling for weather conditions and day of the week. RESULTS: Single-effect models showed, for all-cause mortality, increases of 5.5% (95% CI 1% to 10%) at lag1 and 6.6% (2% to 11.4%) at lag2; cumulative exposure models (0-2 days) showed an increase of 6.3% (0.01% to 32.7%). Respiratory mortality increased marginally at 5.3% (-0.02% to 13.2%) with a 1-day lag and 10% (2.1% to 18%) with a 2-day lag per increase of 38.7 µg/m(3) (IQR) in PM(10) levels. When data were stratified by SES (low, medium, and high), only infants with low and medium SES presented a significant increase in risk of all-cause mortality and respiratory mortality in relation to PM(10). O(3) was only significantly related to respiratory mortality in low SES. CONCLUSION: Our results suggest that in the Mexico City Metropolitan Area, infants with lower SES (low to medium) are at higher risk of mortality when exposed to ambient PM(10) and O(3).