The role of insulin resistance in peripheral vascular disease

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Date: August-September 2003
Publisher: The Townsend Letter Group
Document Type: Article
Length: 2,848 words

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Insulin Resistance Syndrome (IRS) plays a primary role in the initiation and perpetuation of disorders of the human vascular system. IRS is an impaired metabolic response to our body's own insulin so that active muscle cells decrease their uptake of glucose. This causes blood insulin levels to be higher. In turn, higher insulin equates to fat cells not being able to give up their energy stores to let us lose weight. This disorder is associated with obesity, vascular disorders, abnormal triglycerides, glucose intolerance (syndrome "X") and Type 2 diabetes mellitus.

Excess fat in the midriff (apple-shaped physiognomy), an increased waist-to-hip ratio and an androgenic shift in hormone metabolism is common in IRS patients. Moreover, when the body cannot metabolize glucose in a natural and normal fashion, the complications include heart disease, stroke, end-stage renal disease, peripheral arterial disease, and nerve damage. (1-7)

IRS is a consequence of the breakdown of homeostatic mechanisms via glucoregulatory substances, including insulin, glucagon, insulin-like-growth factor, somatostatin, human growth hormone, cortisol, and the catacholamines. Binding of insulin to its receptors promotes tissue uptake of glucose (this physiology increases transport of glucose receptors to the cell surface and by increasing the activity of the intrinsic tyrosine kinase type enzymes which phosphorylate glucose once it is inside the cell).

A high percentage of patients with hypertension are estimated to have insulin resistance. The main problem is that this condition can exist unrecognized and metabolic damage can occur before a full blown Type 2 diabetes is finally diagnosed. Insulin resistant diabetics are 2-5 times more likely to die from heart attack or stroke than are non diabetics. (1-7)

Failure to treat IRS results in abnormalities in glucose and lipid (blood fats) metabolism, obesity, and high blood pressure. In fact, this cluster of abnormalities has been called Syndrome X, and the Deadly Quartet.

Insulin resistance is a reduced sensitivity in the tissues of the body to the action of insulin, which brings glucose into tissues to be used as a source of energy. And, when insulin resistance, or reduced insulin sensitivity, is present the body attempts to overcome this resistance by secreting more insulin from the pancreas. The result of this compensatory physiology: hyperinsulinemia (high insulin levels in the blood) results in the development of Type II, or non-insulin dependent, diabetes because the pancreas eventually fails to sustain this increase insulin secretion. According to Jennifer B. Marks, MD of the University of Miami School of Medicine, insulin resistance contributes directly to abnormalities in blood lipids--cholesterol and triglycerides. (7)

Compensating for IRS is critical as this syndrome is typically characterized by varying degrees of glucose intolerance, abnormal cholesterol and/or triglyceride levels, high blood pressure, and upper body obesity, all independent risk factors for cardiac disease. IRS combined with other stressors, the aging process, a sedentary lifestyle, and genetic susceptibility lead to increased cardiovascular (heart and blood vessels) disease risk. Experts agree that the mere presence of any one major feature alone substantially increases the risk of heart disease, but when they...

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Gale Document Number: GALE|A107201204