Submitted by: Submitted by agathorius
Views: 10
Words: 1468
Pages: 6
Category: Science and Technology
Date Submitted: 05/10/2016 03:17 PM
Eric Bendel
Dr. Snow
5/9/2016
Effect of Extracellular Vesicles of Human Adipose Tissue on Insulin Signaling in Liver and
Muscle Cell
Abstract:
Insulin resistance (IR) plays and important role in obesity-induced cardiovascular disease. The
effects of adipose tissue-extracellular vesicles (AT-EVs) on insulin signaling was measured in
both muscle cells and liver cells. Based on this study, it was speculated that human AT-EVs can
positively or negatively affect insulin signaling in hepatocytes- possibly depending on adipokine
content- and thereby could contribute to systemic IR.
Background:
Insulin resistance (IR) and type 2 diabetes, which are often linked to obesity, greatly
increase the risks for cardiovascular disease (CD) and studies suggest that IR is a key process in
obesity-induced cardiovascular disease. Tissues such as the liver, fat, and muscle have a lesser
response to hormone insulin during insulin-resistant states; which results in things such as
impaired glucose uptake into muscles and impaired regulation of gluconeogenesis in the liver.
Visceral adipose tissue (VAT) is more strongly related to IR and CD than subcutaneous
AT (SAT). Disease contribution from VAT and SAT, though not fully understood, is probably
based on the fact that VAT has a more pronounced AT-inflammation than that of SAT.
Adipokines such as tumor necrosis factor alpha (TNF-a), interleukin-6 (IL-6), retinolbinding protein-4 (RBP-4), and macrophage migration inhibitory factor (MIF) are secreted by
inflamed AT. These adipokines act as inducers of IR. AT-inflammation induces lipolysis; which
increases systemic free fatty acids (FFA); which can activate the innate immune signaling
pathway in muscle and liver cells. This causes lipid-induced IR by accumulation of
diacylglycerols (DAG) and ceramides.
AT of obese mice (as well as human AT) secretes extracellular vesicles (EVs), which are
associated with systemic IR. EVs contain proteins, RNA, and lipids that...