Why are diabetic cataracts less common in cats?

Why are diabetic cataracts less common in cats?

• A. Reduced aldose reductase activity
• B. Higher aldose reductase activity
• C. Reduced lens pigment
• D. Increased oxidative stress

Answer: (A)

Diabetic cataracts depend on how much glucose is turned into sorbitol in the lens. Aldose reductase catalyzes that conversion, and sorbitol accumulation inside the lens draws water and causes osmotic swelling, leading to opacities. Cats have reduced aldose reductase activity in the lens, so even with high blood glucose, the polyol pathway isn’t highly activated. This limits sorbitol buildup and reduces osmotic stress, making cataracts less likely. If aldose reductase activity were higher, sorbitol would accumulate more and cataracts would be more common, which contradicts the observed feline pattern. The other options don’t fit the mechanism: lens pigment levels and oxidative stress are not the primary drivers explaining why cats are less prone to diabetic cataracts.

Diabetic cataracts depend on how much glucose is turned into sorbitol in the lens. Aldose reductase catalyzes that conversion, and sorbitol accumulation inside the lens draws water and causes osmotic swelling, leading to opacities. Cats have reduced aldose reductase activity in the lens, so even with high blood glucose, the polyol pathway isn’t highly activated. This limits sorbitol buildup and reduces osmotic stress, making cataracts less likely.

If aldose reductase activity were higher, sorbitol would accumulate more and cataracts would be more common, which contradicts the observed feline pattern. The other options don’t fit the mechanism: lens pigment levels and oxidative stress are not the primary drivers explaining why cats are less prone to diabetic cataracts.