Cataracts, in diabetes

The same mechanism accounts for the cataracts in diabetics because aldose reductase also converts glucose to sorbitol, which causes osmotic damage. 

Aldose reductase has been implicated in the pathogenesis of cataract in diabetic and galactosaemic animals. The enzyme catalyzes the reduction... 

Lens aldose reductase has been implicated in the pathogenesis of cataracts in diabetic and galac-tosemic animals. The enzyme catalyzes the reduction of glucose and galactose to their polyols, which accumulate in large quantities in the lens and ultimately lead to mature lens opacities. Several key bioflavones have activity against this enzyme. Oral administration of quercitrin decreased the accumulation of sobital in the lens. Therefore, the accumulation of lens opacities could be partially abrogated by certain flavonoids. In a study of 30 flavones, 4 isoflavones, and 13 coumarins, many potent inhibitors were found, but 5,7,3, 4 -tetrahydroxy-3,6-dimethoxyflavone and 6,3, 4 -trihy-droxy-5,7,8-trimethoxyflavone were especially active. 

Dietary curcumin (0.002% and 0.01%) and turmeric (0.5%) are found to be effective against the development of diabetic cataracts in diabetic rats (Suryanarayana et al. 2005). Curcumin and turmeric supplements... 

The accumulation of sorbitol and consequent uptake of water leads to opacification of the lens, 1.e. diabetic cataract. In diabetic rabbit lens, formation of fructose and sorbitol was enhanced, while that of myo-inositol decreased, relative to normal lens. The following polyols have been identified in human urine for the first time 4-deoxythreitol, 4-deoxyerythritol, 5-deoxyxylitol, 5-deoxy-... 

Calpain Tissue specific calpains have been implicated in diabetes, cataracts, multiple sclerosis, and limb-girdle muscular dystrophy type 2A. More than 50 inhibitors of calpain have described which have a potential for therapeutic applications. 

Diabetes mellitus can have serious secondary effects. A constantly raised blood sugar level can lead in the long term to changes in the blood vessels (diabetic angiopathy), kidney damage (nephropathy) and damage to the nervous system (neuropathy), as well as to cataracts in the eyes. 

Lee AY, Chung SS (1999) Contributions of polyol pathway to oxidative stress in diabetic cataract. FASEBJ 13 23-30... 

Complications in diabetes (cataract formation and nephropathy in particular). 

T.J. Lyons, G. Silvestri, J.A. Dunn, D.G. Dyer, and J.W. Baynes, Role of glycation in modification of lens crystallins in diabetic and non-diabetic senile cataracts, Diabetes, 1991, 40, 1010-1015. 

In Ayurveda and folklore medicines, cinnamon is used in the treatment of diabetes. Cinnamon is reported to reduce the blood glucose level in non-insulin-dependent diabetics. Therapeutic studies have proved the potential of cinnamaldehyde as an antidiabetic agent. Cinnamaldehyde inhibits aldose reductase, a key enzyme involved in the polyol pathway. This enzyme catalyses the conversion of glucose to sorbitol in insulin-insensitive tissues in diabetic patients. This leads to accumulation of sorbitol in chronic complications of diabetes, such as cataract, neuropathy and retinopathy. Aldose-reductase inhibitors prevent conversion of glucose to sorbitol, thereby preventing several diabetic complications (Lee, 2002). 

Some typical structural templates embedded with the thiazoHdine frame have been reported as potent inhibitors of aldose reductase (AR), an enzyme in the polyol pathway responsible for the conversion of glucose to sorbitol. In this, the accumulation of sorbitol has been attributed to causing cataracts, neuropathy, and retinopathy in diabetic cases [ 157,158]. The planar hydrophobic (aromatic) regions and propensity to charge transfer interactions have been... 

Topical ocular steroid administration also may cause the development of cataracts in both children and adults. Use of topical steroids for several years to eliminate redness associated with contact lens wear resulted in PSC formation as well as glaucoma and visual field loss. The opacities associated with steroid administration resemble those produced by ionizing radiation and ocular disease such as uveitis, retinitis pigmentosa, and retinal detachment. They differ from opacities associated with diabetes and trauma but are indistinguishable from lens changes associated with posterior subcapsular age-related cataract. 

Elevated glucose in diabetes meliitus may result in sorbitol deposition in the lens and neural tissues, contributing to cataracts and peripheral neuropathy. 

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