Mechanisms of insulin resistance assessed by dynamic in-vivo positron emission tomography imaging

PURPOSE OF REVIEWSkeletal muscle insulin resistance is a hallmark characteristic of type 2 diabetes, although the exact causes of insulin resistance are unknown. In-vivo methods to assess mechanisms that determine insulin resistance in humans are critical to improve our understanding of insulin resistance in obesity and type 2 diabetes. In this review, we examine recent studies utilizing dynamic in-vivo PET imaging in assessing insulin resistance in humans. RECENT FINDINGSPET imaging of glucose metabolism in vivo has revealed novel and important information about the regulation of glucose metabolism in skeletal muscle. Using dynamic PET imaging, studies have impairments in glucose metabolism at multiple sites, including delivery, phosphorylation, and transport within skeletal muscle. Impairments in glucose phosphorylation as well as glucose transport defects may play an important role in understanding the disorder of skeletal muscle insulin resistance. SUMMARYPET imaging has great potential to yield significant and promising insight into insulin resistance in skeletal muscle. Dynamic in-vivo PET imaging can provide valuable information regarding the mechanisms and specific loci of skeletal muscle insulin resistance in humans.