Acceleration of Development of Diabetic Cataract by Hyperlipidemia and Low High-Density Lipoprotein in Rats.

Abstract

Diabetic cataracts are thought to be caused by hyperglycemia associated with disturbed glucose metabolism. Diabetes mellitus often involves abnormal lipid metabolism in addition to abnormal glucose metabolism. To date, however, very few studies have counted hyperlipidemia as a risk factor for diabetic cataracts. The present study was undertaken to determine whether this abnormal lipid metabolism is a risk factor for diabetic cataracts in rats. Cataracts were caused by streptozotocin (STZ) administration in the ordinary diet or cholesterol rich diet fed rats. When rats with STZ (65 mg/kg)-induced diabetes mellitus were fed an ordinary diet, cataracts became evident at 9 weeks in 26.7% of animals, and increased to an incidence of 53.3% after 10 weeks of STZ treatment. However, in rats with STZ-induced diabetes mellitus that were fed a cholesterol rich diet to induce severe hyperlipidemia and low high density lipoprotein (HDL) cholesterol, cataracts were observed one week earlier, after 8 weeks of treatment, in 40.0% of animals, with an increase to a 53.3% incidence and an 86.7% incidence after 9 and 10 weeks of STZ treatment, respectively. Plasma glucose levels did not differ between the groups. These results suggest that hyperlipidemia and low HDL cholesterol are associated with an earlier onset and an elevated incidence of diabetic cataracts. We then investigated the relationship between plasma lipids and cataracts by STZ (45-85 mg/kg) administration. The results showed that the onset of cataracts correlated positively with plasma total cholesterol, triglyceride, non-HDL cholesterol and glucose levels, and negatively with HDL cholesterol levels. The results of this study suggest that hyperlipidemia and low HDL cholesterol levels may be risk factors for the onset of diabetic cataracts and that diabetic cataracts may be accelerated by hyperlipidemia and low HDL cholesterol in rats.

Is cataract associated with cardiovascular morbidity?

“…28 Animal studies indicate that these factors interact to promote cataract development, and modification of one factor may be used to reduce risk from another. 29 Similar to our findings, HTN has also been associated with cataract in other cross-sectional 30 and case-control studies. However, the results are inconsistent 31 and the Blue Mountains Eye Study even reported HTN to be inversely related to nuclear cataract (OR ¼ 0.8).…”

Community-based study of cataracts among type 2 diabetics in Kinmen

“…Other cross-sectional studies also reported that either no association with serum cholesterol levels or higher levels of serum cholesterol in controls [20,21]. One animal study had suggested a possible association between abnormal lipid metabolism and the early onset of diabetic cataracts [22]. Both whole blood glutathione values and erythrocyte superoxide dismutase activities, the indicator of lipid peroxidation concentrations, were significantly lower in the diabetic cataractous patients than those in the senile cataractous group [23].…”

Gender Difference in the Association of Metabolic Syndrome and Its Components with Age-Related Cataract: The Korea National Health and Nutrition Examination Survey 2008-2010

“…A strong association was found between low levels of HDL cholesterol and the development of lens opacities of adults of both genders from South Africa [38]. Animal studies have shown acceleration of the development of diabetic cataracts by hyperlipidemia and low HDL in rats [39]. Inflammation and oxidative stress resulting from reduced HDL cholesterol levels could induce cataract formation [28], [40]–[42].…”