Hyperglycemia is considered a key risk factor for development of
diabetic complications including neuropathy. There is strong scientific evidence showing a primary role of
aldose reductase, the first
enzyme of the
polyol pathway, in the cascade of metabolic imbalances responsible for the detrimental effects of
hyperglycemia.
Aldose reductase is thus considered a significant drug target. We investigated the effects of
cemtirestat, a novel
aldose reductase inhibitor, in the
streptozotocin-induced rat model of uncontrolled
type 1 diabetes in a 4-month experiment. Markedly increased
sorbitol levels were recorded in the erythrocytes and the sciatic nerve of diabetic animals. Osmotic fragility of red blood cells was increased in diabetic animals. Indices of thermal hypoalgesia were significantly increased in diabetic rats.
Tactile allodynia, recorded in diabetic animals in the early stages, turned to mechanical hypoalgesia by the end of the experiment. Treatment of diabetic animals with
cemtirestat (i) reduced plasma
triglycerides and TBAR levels; (ii) did not affect the values of HbA1c and
body weights; (iii) reversed erythrocyte
sorbitol accumulation to near control values, while
sorbitol in the sciatic nerve was not affected; (iv) ameliorated indices of the erythrocyte osmotic fragility; and (v) attenuated the symptoms of
peripheral neuropathy more significantly in the middle of the experiment than at the end of the treatment. Taking into account the lipid metabolism as an interesting molecular target for prevention or treatment of diabetic
peripheral neuropathy, the
triglyceride-lowering effect of
cemtirestat should be considered in future studies. The most feasible mechanisms of
triglyceride-lowering action of
cemtirestat were suggested.