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Updated: Jul 12, 2026
Murine Renal Transplantation Procedure
Published on: July 10, 2009
Azoospermia in a renal transplant recipient during sirolimus (rapamycin) treatment
1Department of Dermatology and Allergology, School of Medicine, Philipps University, Marburg, Germany. skrzypek@mailer.uni-marburg.de
Abstract:
Sirolimus is used as a powerful immunosuppressant drug in patients after organ transplantation. It was shown to block spermatogenesis by interrupting the stem cell factor/c-kit system. Oligozoospermia was shown in single patients. In addition, a decrease of testosterone and an increase of gonadotropin levels were observed. We report on a young patient who showed azoospermia during the treatment with sirolimus after renal transplantation. After changing the immunosuppression to tacrolimus, spermatogenesis of the patient recovered. Five months after cessation of the treatment with sirolimus, a sperm concentration of 8 x 10(6) ml(-1) was found. Depression of spermatogenesis is an important side effect in younger men who aspire paternity, so that waiving of sirolimus is advisable in these patients.
Insights
Sirolimus, an immunosuppressant, can impair sperm production by affecting the stem cell factor/c-kit pathway. Reversing this effect is possible by switching to tacrolimus, aiding fertility in transplant patients.
Area of Science:
- Immunology
- Reproductive Medicine
- Pharmacology
Background:
- Sirolimus is a potent immunosuppressant used post-organ transplantation.
- Previous studies indicate sirolimus can disrupt spermatogenesis via the stem cell factor/c-kit system.
- Oligozoospermia, decreased testosterone, and increased gonadotropin levels have been observed in patients on sirolimus.
Observation:
- A young renal transplant patient experienced azoospermia during sirolimus therapy.
- Hormonal changes included decreased testosterone and increased gonadotropins.
Findings:
- Spermatogenesis resumed after immunosuppression was switched from sirolimus to tacrolimus.
- Significant sperm concentration was noted five months after sirolimus discontinuation.
Implications:
- Sirolimus-induced testicular toxicity is a reversible side effect.
- Discontinuation or avoidance of sirolimus is recommended for young men desiring paternity.
- This highlights the importance of fertility preservation in transplant recipients.
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