Six weeks after renal transplantation, a recipient converted from tacrolimus to sirolimus because of rising creatinine returns with a copious serous discharge from his lower midline wound. Which property of sirolimus best explains this complication?

• A Inhibition of vascular endothelial growth factor release
• B Induction of a systemic corticosteroid-like catabolic state
• C Direct inhibition of collagen cross-linking by lysyl oxidase
• D Impairment of fibroblast proliferation through mTOR blockade, delaying wound healing ✓

Explanation

Sirolimus blocks the mammalian target of rapamycin, arresting cells in the G1 phase. Fibroblast and smooth muscle proliferation are therefore suppressed, producing delayed wound healing, wound dehiscence, and lymphocele formation, particularly when started early after surgery. Its great advantage over calcineurin inhibitors is the absence of nephrotoxicity, which is exactly why this patient was switched. Wound complications are the trade-off tested here.

Reference: Schwartz Principles of Surgery, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.