A 48-year-old man undergoes living-donor renal transplantation and is started on tacrolimus, mycophenolate mofetil and prednisolone. His surgeon adds sirolimus to the regimen. Two weeks later he develops poor healing of the wound with serous discharge and partial fascial dehiscence. Which property of sirolimus best explains this complication?
- A It causes leukopenia leading to wound infection
- B It inhibits mTOR signalling required for fibroblast proliferation and angiogenesis ✓
- C It induces a hypercoagulable state causing microvascular thrombosis of the wound edge
- D It causes hyperkalaemia impairing collagen cross-linking
Correct answer: B. It inhibits mTOR signalling required for fibroblast proliferation and angiogenesis
Explanation
Sirolimus blocks mTOR, which is needed for IL-2 driven T-cell proliferation, but the same pathway drives fibroblast proliferation, collagen deposition and new vessel formation in healing tissue. Wound dehiscence, lymphocele and delayed wound healing are recognised sirolimus complications, so many centres delay starting it until the incision has healed. Leukopenia is more typical of mycophenolate and does not cause dehiscence itself.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.