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Microvascular Content and Insulin Sensitivity within Skeletal Muscle and Adipose Tissue Differs between Male and Female Mice on a High‐fat Diet
Author(s) -
Abdifarkoosh Ghoncheh,
Rudnicki Martina,
Roudier Emilie,
Haas Tara L.
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.678.9
Subject(s) - medicine , endocrinology , adipose tissue , skeletal muscle , insulin , biology , stimulation , insulin resistance , metabolic syndrome , brown adipose tissue , obesity , insulin receptor
Capillary networks within skeletal muscle and adipose tissue have a critical role in the delivery of energy sources and the maintenance of proper tissue function. A reduction in capillary density is correlated with impairments in whole body metabolic functions, as occurs in obesity. It is known that the susceptibility to develop obesity‐associated metabolic disturbances differs between males and females. However, studies investigating these sex‐related differences have largely overlooked the potential contribution of capillary content. The goal of this investigation is to determine whether there are sex differences in skeletal muscle and adipose tissue microvascular content and to relate these to insulin signaling in normal and obese mice. Male mice fed a high‐fat (HF) diet for 16 weeks exhibited reduced systemic insulin sensitivity compared to females who maintained a response similar to the normal‐chow (NC) group. Insulin stimulation increased levels of phosphorylated Akt (pAkt) protein equivalently in the skeletal muscle of male and female NC mice. With HF diet, males had significantly lower insulin‐stimulated pAkt levels vs. females (0.7 vs. 1.9, P <0.0001). Capillary‐to‐fiber ratio was not different in the skeletal muscle of HF male vs. female mice (1.5 vs. 1.4, n=3 ns). Ex vivo insulin stimulation of visceral adipose tissue increased pAkt in HF females but not in HF males. Microvascular content in visceral adipose was not different between NC males and females. In contrast, HF males had reduced, but HF females maintained, their adipose vascular content. This was further supported by higher mRNA levels of vascular marker CD31 (0.17 vs. 0.12, p< 0.05) and pro‐angiogenic factor VEGF (0.14 vs. 0.07, p< 0.05) in HF females vs. HF males. Our data suggest that capillary content and a pro‐angiogenic environment is maintained in the adipose of HF‐fed females, which in turn may be linked with maintained adipose insulin sensitivity. Support or Funding Information CIHR