metabolic disorders

In Utero Maternal Benzene Exposure Predisposes to the Metabolic Imbalance in the Offspring

AUTHORS

Lisa Koshko, Lucas K Debarba, Mikaela Sacla, Juliana B M de Lima, Olesya Didyuk, Patrick Fakhoury, Marianna Sadagurski

ABSTRACT

Environmental chemicals play a significant role in the development of metabolic disorders, especially when exposure occurs early in life. We have recently demonstrated that benzene exposure, at concentrations relevant to cigarette smoke, induces a severe metabolic imbalance in a sex-specific manner affecting male but not female mice. However, the roles of benzene in the development of aberrant metabolic outcomes following gestational exposure, remain largely unexplored. In this study, we exposed pregnant C57BL/6JB dams to benzene at 50 ppm or filtered air for 6 h/day from gestational day 0.5 (GD0.5) through GD21 and studied male and female offspring metabolic phenotypes in their adult life. While no changes in body weight or body composition were observed between groups, 4-month-old male and female offspring exhibited reduced parameters of energy homeostasis (VO2, VCO2, and heat production). However, only male offspring from benzene-exposed dams were glucose intolerant and insulin resistant at this age. By 6 months of age, both male and female offspring exhibited marked glucose intolerance however, only male offspring developed severe insulin resistance. This effect was accompanied by elevated insulin secretion and increased beta-cell mass only in male offspring. In support, Homeostatic Model Assessment for Insulin Resistance, the index of insulin resistance was elevated only in male but not in female offspring. Regardless, both male and female offspring exhibited a considerable increase in hepatic gene expression associated with inflammation and endoplasmic reticulum stress. Thus, gestational benzene exposure can predispose offspring to increased susceptibility to the metabolic imbalance in adulthood with differential sensitivity between sexes.

FIAT deletion increases bone mass but does not prevent high-fat-diet-induced metabolic complications

FIAT (Factor Inhibiting ATF4-mediated Transcription) interacts with ATF4 to repress its transcriptional activity. We performed a phenotypic analysis of Fiat-deficient male mice (Fiat-/Y) at 8 and 16 weeks of age. Fiat-/Y mice appeared normal at birth and weight gain was comparable between genotypes. μCT analysis of proximal femur demonstrated 46% and 13% age-dependent increases in trabecular bone volume and thickness, respectively, in Fiat-/Y mice.