linoleic-acid and Diabetic-Retinopathy

One hundred and forty nine diabetic patients were ophthalmologically assessed seven years after randomisation to a low carbohydrate or modified fat diet (rich in linoleic acid). Glycaemic control, regardless of the type of diet, was a major determinant of the development of retinopathy. Poorly controlled patients (haemoglobin A1c greater than 8%) with low levels of linoleic acid in cholesterol ester had a significantly greater frequency of retinopathy than well controlled patients or patients with similarly unsatisfactory control but higher levels of linoleic acid. The findings support an earlier suggestion that linoleic acid might protect against diabetic retinopathy.

Topics: Cholesterol Esters; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Diet, Diabetic; England; Fatty Acids, Unsaturated; Female; Glycated Hemoglobin; Humans; Linoleic Acid; Linoleic Acids; Male; Middle Aged; Prospective Studies; Random Allocation

An excess of Oxidative Stress can occur either through an increase in the generation of free radicals and their metabolites (which overwhelm the protective capacity of the normal defence mechanisms of the body) or through a decrease in the protective ability of the body to withstand normal Oxidative Stress or both. Excessive Oxidative Stress plays an important role in the pathogenesis of diabetes and its chronic complications like retinopathy and nephropathy. Through various mechanisms, it plays a prominent role in the progression and acceleration of atherosclerosis. Free radicals being highly unstable due to their high reactivity are very difficult to measure accurately. Recourse is therefore taken to measure the compounds that are formed due to the activity of these free radicals. These compounds are relatively more stable and therefore can be measured as diene congugate and lipid peroxides. Another valuable measurement is to measure the levels of reduced glutathione in serum. Measurements of these products can be an excellent parameter to judge the metabolic control of diabetes.

Topics: Adult; Aged; Antioxidants; Arteriosclerosis; Diabetes Mellitus; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Retinopathy; Disease Progression; Evaluation Studies as Topic; Female; Free Radicals; Glutathione; Humans; Linoleic Acid; Linoleic Acids; Lipid Peroxides; Male; Middle Aged; Myocardial Ischemia; Oxidative Stress

The retinae of 137 patients were examined ophthalmologically and for visual acuity at diagnosis of non-insulin dependent diabetes and again in 1982 and 1983, approximately 7 and 8 years later, when colour photographs were also taken. In 1983, 46% were without detectable retinopathy, 32% had haemorrhages (including microaneurysms) only, 4% exudates alone and 18% both lesions. Those with haemorrhages were more hyperglycaemic than those without retinopathy and those with exudates only. Indeed, those with exudates alone had lower mean glucose levels than those without retinopathy (p less than 0.05). Patients with exudates (+/- haemorrhages) had a lower percentage of the fatty acids of plasma cholesterol esters as linoleate than those without (p less than 0.05) but this did not hold for those developing haemorrhages. Different risk factors appear to operate in different features of diabetic retinopathy. In some respects exudate formation may be more akin to macro than to micro angiopathy.

Topics: Aged; Aneurysm; Cholesterol Esters; Diabetic Retinopathy; Exudates and Transudates; Humans; Linoleic Acid; Linoleic Acids; Middle Aged; Prospective Studies; Retina; Retinal Hemorrhage; Risk

Platelet function, estimated from plasma beta-thromboglobulin (beta-TG, ng/ml), is frequently altered in insulin-dependent diabetics (IDDs). As several factors may affect beta-TG, we studied respectively in 15 IDDs, the roles played by: (i) diabetic control evaluated from glycosylated haemoglobin (HbA1); (ii) plasma C-peptide and pancreatic glucagon; (iii) plasma lipids and the relative percentages of fatty acids in total plasma lipids. Plasma beta-TG did not correlate significantly with the first 3 parameters. However, beta-TG was correlated: (i) positively with plasma triglycerides (P less than 0.01), cholesterol (P less than 0.02), phospholipids (P less than 0.05) and total plasma lipids (P less than 0.01) and the percentage of oleic acid (C18 : 1 omega 9) in plasma lipids (P less than 0.01); (ii) negatively with the percentage of linoleic acid (C18 : 2 omega 6) in plasma lipids (P less than 0.02). No correlation was found between beta-TG and the percentages of the other saturated (C16 : 0, C18 : 0), monounsaturated (C16 : 1 omega 7) and polyunsaturated fatty acids (C18 : 3 omega 6, C20 : 3 omega 6 and C20 : 4 omega 6). The present results indicate that beta-TG in IDDs can be markedly improved by all dietary and therapeutic measures which lower plasma lipids and increase the percentage of the linoleic acid in the body.

Topics: Adult; Aged; beta-Thromboglobulin; Blood Platelets; Cholesterol; Diabetes Mellitus, Type 1; Diabetic Retinopathy; Fatty Acids; Female; Humans; Linoleic Acid; Linoleic Acids; Lipids; Male; Middle Aged; Oleic Acid; Oleic Acids; Phospholipids; Triglycerides