A patient with uncontrolled diabetes mellitus experiences persistent hyperglycemia. Over time, this leads to damage to the basement membranes of small blood vessels in the kidneys, eyes, and nerves. This long-term complication is primarily due to:
- AIncreased insulin sensitivity in peripheral tissues.
- BGlycation of proteins, leading to advanced glycation end products (AGEs).
- CDecreased production of inflammatory cytokines.
- DOxidative stress caused by excessive glucose metabolism.
Show answer & explanationAnswer & explanation
Correct answer: B. Glycation of proteins, leading to advanced glycation end products (AGEs).
Persistent hyperglycemia in diabetes leads to the non-enzymatic glycation of proteins, where glucose molecules attach to proteins without the need for an enzyme. This process forms advanced glycation end products (AGEs), which accumulate in tissues, including the basement membranes of blood vessels, contributing to their stiffening, thickening, and dysfunction, characteristic of diabetic complications.
Why the other options are wrong
- A. Uncontrolled diabetes is characterized by insulin resistance (decreased sensitivity), not increased sensitivity.
- C. Uncontrolled diabetes typically leads to increased inflammation, not decreased cytokine production.
- D. While oxidative stress is a contributing factor in diabetic complications, glycation and AGE formation are a more direct and primary mechanism for basement membrane damage.
Protein Glycation in Diabetes
Protein glycation is a non-enzymatic reaction where glucose molecules attach to amino groups of proteins, forming Schiff bases and then Amadori products. Over time, these can rearrange and cross-link to form Advanced Glycation End products (AGEs), which contribute significantly to diabetic complications by altering protein structure and function.
- Non-enzymatic attachment of glucose to proteins.
- Forms Advanced Glycation End products (AGEs).
- AGEs accumulate in tissues (e.g., blood vessel basement membranes).
- Contributes to microvascular and macrovascular complications of diabetes.
Memory trick: Hyperglycemia: 'High' 'Glucose' makes 'Glycated' proteins 'Damage' tissues.