Elastin Insufficiency Predisposes Mice to Impaired Glucose Metabolism

Williams-Beuren syndrome is the consequence of a large contiguous-gene deletion on the seventh human chromosome that includes the elastin gene. Elastin is an extracellular matrix protein responsible for the cardiovascular abnormalities associated with Williams's syndrome, including hypertension and aortic stenosis. A high percentage of individuals with Williams's syndrome also have impaired glucose tolerance, independent of traditional risk factors for diabetes. Here, we show that murine adipose tissue does assemble elastic fibers; however, isolated elastin insufficiency (Eln^+/-) in mice does not independently influence glucose metabolism or tissue lipid accumulation. Similarly, isolated ApoE deficiency (ApoE^-/-), a model of hyperlipidemia and atherosclerosis, does not impair insulin sensitivity. However, Eln^+/-; ApoE^-/- double mutant mice exhibit notable hyperglycemia, adipocyte hypertrophy, inflammation of adipose tissue, and ectopic lipid accumulation in liver tissue. Further, Eln^+/-; ApoE^-/- mutants have significant impairment of insulin sensitivity by insulin tolerance testing, independent of body weight or diet, suggesting that elastin insufficiency predisposes to metabolic disease in susceptible individuals.