Renal System MCAT Practice Question
A 45-year-old man with a 15-year history of type 2 diabetes mellitus presents for routine urinalysis. Laboratory findings show a serum creatinine of 1.8 mg/dL (previously 1.0 mg/dL 6 months ago) and 24-hour urine protein of 3.2 g. Renal ultrasound demonstrates bilateral kidney enlargement without hydronephrosis. A kidney biopsy is performed and shows nodular glomerulosclerosis with thickened glomerular basement membranes and expansion of the mesangial compartment. Which of the following cell types is primarily responsible for the excessive extracellular matrix accumulation observed in this patient's glomeruli?
Answer choices
- AGlomerular endothelial cells responding to VEGF signaling
- BMesangial cells producing collagen and proteoglycansCorrect answer
- CPodocytes differentiating into fibroblasts
- DParietal epithelial cells lining Bowman's capsule
- EInfiltrating macrophages secreting cytokines
- FJuxtaglomerular cells in response to renin activation
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