DOC News November 1, 2007
Volume 4 Number 11 p. 15
© 2007 American Diabetes Association
Fat Infiltrates Heart Before Diabetes Onset
Heart tissue gets fatty in people with impaired glucose tolerance long
before they show signs of diabetes or heart disease, according to a recent
report.
A group of investigators from University of Texas Southwestern Medical
Center, Dallas VA Medical Center, and the Institute for Exercise and
Environmental Medicine at Presbyterian Hospital in Dallas employed magnetic
resonance spectroscopy to measure myocardial triglyceride content in 134
participants.
The subjects were chosen to represent the progressive stages in the natural
history of type 2 diabetes: Those who were lean and had normal blood glucose
levels; those who were overweight or obese who still had normal blood glucose
levels; those who had impaired glucose tolerance; and those with full-blown
type 2 diabetes.
Software allowed investigators to determine levels of triglycerides in
cardiac muscle cells versus adipocytes. They also measured triglycerides in
the liver and subcutaneous and visceral fat. Left ventricular function was
measured by cardiac magnetic resonance imaging.
The group found that levels of triglycerides in the cardiac muscle were 2.3
times higher in people with impaired glucose tolerance, compared with lean,
normoglycemic people. Triglyceride levels were 2.1 times higher in people with
type 2 diabetes, the researchers found. No differences were noted in any group
in terms of left ventricular function.
"Impaired glucose tolerance is accompanied by cardiac steatosis,
which precedes the onset of type 2 diabetes and left ventricular systolic
dysfunction," the researchers conclude. "Thus, lipid overstorage
in human cardiac myocytes is an early manifestation in the pathogenesis of
type 2 diabetes mellitus and is evident in the absence of heart
failure."
McGavock JM, Lingvay I, Zib I, et al.: Cardiac steatosis
in diabetes mellitus. Circulation 116: 1170–1175, 2007.[Abstract/Free Full Text]

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