Guest guest Posted August 28, 2000 Report Share Posted August 28, 2000 From author Elzi Volk to the " low-carbing gods' list " , responding to Carroll ... *************** This phenonemon is a basic biochemical reaction. In fact, it is a contribution to normal aging of tissues and accelerated aging of tissues (especially connective tissue) seen in diabetics, ultimately leading to associated complications. Oxidative damage coupled with non-enzymatic glycation of tthese tissues area result of excess glucose as well as other factors. Excerpted from my article on connective tissue: " Changes in connective tissue in diabetics parallel those evident in aging and cause many complications seen in later stage diabetes. The most apparent clinical disorders affect the skin, eyes, arteries and kidneys. Arteries and joints of diabetics become prematurely stiff with decreased elasticity. Nonenzymatic glycation of collagen protein and oxidative stress are associated with aging and diabetes, and caused by hyperglycemia ('glucose toxicity') (4,5,6 ,7, 8). Excessive plasma and tissue glucose undergo reactions that produce advanced glycation products. The long-lived proteins of collagen and elastin accumulate enough advanced glycation products that irreversibly alter many of the protein's physical properties. The collagen becomes saturated and excessively cross-linked inhibiting normal turnover. Progressive changes in properties ultimately modify arrangements and functioning of the tissue (8). These alterations in the matrix may affect cell behavior such as migration, growth, proliferation and gene expression. Glycation is the nonenzymatic reaction between a sugar and the free amino acid group of proteins. Several mechanisms initiate glycation including glucose auto-oxidation and the Amadori degradation pathway. Lipid peroxidation (oxidation of polyunsaturated fatty acids) may also contribute to oxidative reactants. Intermediates of carbohydrate peroxidation are similar to lipid peroxidation; both form carboxymethyllysine (CML). Under oxidative conditions and in the presence of a transition metal, such as copper or iron, CML forms and accumulates in tissue, altering collagen cross-linking. Other advanced glycation products also affect the physical, chemical and mechanical properties of collagen protein. Collagen becomes browned and excessively cross-linked, altering its tensile strength. Diabetic rats exhibit acceleration of procollagen degradation in tendons (9). An interventional strategy that shows success in animal models is glycemic control and is discussed further along with carbohydrate nutrition. " Quote Link to comment Share on other sites More sharing options...
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