3D analysis of capillary network in skeletal muscle of obese insulin-resistant mice

Mechanisms of muscle insulin resistance and the cross‐talk with liver and adipose tissue

“…In obesity and insulin resistance, the skeletal muscle capillary network is compromised, impairing insulin-mediated capillary recruitment. A study by Umek et al (2019) investigated the possibility that the anatomical changes in the capillary network could be linked to fiber-type specific differences. Capillary density was found to be increased in small muscle fibers (type I) compared to large fibers (type II) and is attributed to increased capillarization selectiveness towards more insulin-sensitive oxidative muscle fibers (Umek et al, 2019).…”

“…A study by Umek et al (2019) investigated the possibility that the anatomical changes in the capillary network could be linked to fiber-type specific differences. Capillary density was found to be increased in small muscle fibers (type I) compared to large fibers (type II) and is attributed to increased capillarization selectiveness towards more insulin-sensitive oxidative muscle fibers (Umek et al, 2019). Their findings suggest that the selective increase in capillarization surrounding more insulin-sensitive oxidative muscle fibers act to alleviate obesity-related insulin resistance (Umek et al, 2019).…”

“…Obese insulin‐resistant humans and mice present muscle fiber type transformation, which provides a possible mechanism related to impaired glucose metabolism and T2D. Although intriguing in the context of diabetic microangiopathy, further studies are required to more fully appreciate these observations (Albers et al., 2015; Umek et al., 2019).…”

In focus in HCB

“…The identification of muscle fiber subtypes, along with capillary density assessments is of critical importance in muscle training experiments, following nerve injuries (Cebasek and Ribaric 2019), or in relation to specific pathologies or disease entities (Umek et al 2019). Techniques have been developed, and progressed over the years to perform these assays on muscle tissue sections through the use of histochemical, immunohistochemical, and lectin cytochemical means.…”

In focus in HCB

“…In this regard, given the world-wide increase in obesity and concomitant type 2 diabetes, an investigation of the potential correlation between obesity and muscle capillarity is of great interest. Umek et al (2019) have performed an extensive morphometric analysis of the capillary network of the mouse gluteus maximus muscle from lean healthy mice versus high-fat-diet (HFD)-induced insulin-resistant littermates. Thick (100 μm), transverse sections of muscle were stained with an anti-collagen IV antibody to visualize basement membranes, and with Griffonia simplicifolia lectin I to visualize capillary endothelial cells, followed by acquisition of 3D stacks of images by confocal microscopy.…”