Reduction of calprotectin and phosphate during testosterone therapy in aging men: a randomized controlled trial

Objectives: To investigate the effect of testosterone treatment on biomarkers calprotectin, fibroblast growth factor 23 (FGF23), soluble Klotho, phosphate, calcium, parathyroid hormone, creatinine and estimated glomerular filtration rate. Design: Randomized, double-blinded, placebo-controlled study. Setting: Odense Androgen Study—the effect of Testim and training in hypogonadal men. Participants: Men aged 60–78 years old with a low normal concentration of free of bioavailable testosterone <7.3 nmol/L and waist circumference >94 cm recruited from 2008 to 2009 (N = 48) by advertisement. Intervention: Participants were randomized to receive 5–10 g gel/50–100 mg testosterone (Testim^®, Ipsen, France) or 5–10 g gel/placebo. Results: The plasma levels of calprotectin and phosphate were significantly reduced in the group receiving testosterone therapy (gel) compared to the placebo group (p < 0.05). Testosterone treatment did not have any significant effect on plasma levels of FGF23 or soluble Klotho. The reduction in phosphate levels was inversely associated with bioavailable testosterone. Conclusion: Compared to the placebo group, 6 months of testosterone therapy (gel) reduced calprotectin and phosphate levels suggesting decreased inflammation and decreased cardiovascular risk.