Androgen-deprivation therapy (ADT) is the primary systemic therapy for treating advanced or metastatic prostate cancer (PCa), which has improved survival outcomes in patients with PCa. However, ADT may develop metabolic and cardiovascular adverse events that impact the quality of life and lifespan in PCa survivors. The present study was designed to establish a murine model of ADT with a gonadotropin-releasing hormone (GnRH) agonist leuprolide and to investigate its effects on metabolism and cardiac function. We also examined the potential cardioprotective role of sildenafil (inhibitor of phosphodiesterase 5) under chronic ADT. Middle-aged male C57BL/6J mice received a 12-wk subcutaneous infusion via osmotic minipumps containing either saline or 18 mg/4 wk leuprolide with or without 1.3 mg/4 wk sildenafil cotreatment. Compared with saline controls, leuprolide treatment significantly reduced prostate weight and serum testosterone levels, confirming chemical castration in these mice. The ADT-induced chemical castration was not affected by sildenafil. Leuprolide significantly increased the weight of abdominal fat after 12-wk treatment without a change in total body weight, and sildenafil did not block the proadipogenic effect of leuprolide. No signs of left ventricular systolic and diastolic dysfunction were observed throughout the leuprolide treatment period. Interestingly, leuprolide treatment significantly elevated serum levels of cardiac troponin I (cTn-I), a biomarker of cardiac injury, and sildenafil did not abolish this effect. We conclude that long-term ADT with leuprolide increases abdominal adiposity and cardiac injury biomarker without cardiac contractile dysfunction. Sildenafil did not prevent ADT-associated adverse changes.
Keywords: GnRH agonists; androgen-deprivation therapy; cardiotoxicity; prostate cancer; sildenafil citrate.