Investigation of phoenix, alpha klotho and relaxin levels in patients with Peyronie's disease

Peyronie's disease (PD) is an inflammatory disorder of the tunica albuginea that can lead to various clinical manifestations, including penile pain, penile deformity, plaque formation, and erectile dysfunction. Although the exact pathogenesis of PD remains unclear, the most widely accepted theory suggests that it represents an abnormal wound-healing disorder accompanied by a fibrotic process triggered by repetitive microtrauma to the penis. In this study, we aimed to measure serum levels of Relaxin, Phoenixin, and α-Klotho, biomolecules known to possess antifibrotic, antioxidative, and anti-inflammatory properties, in patients with Peyronie's disease. Between May 2024 and April 2025, a total of 60 participants were enrolled in the study, including 30 patients with PD and 30 healthy controls without comorbidities, who presented to the outpatient clinic of the Department of Urology at Firat University, Elazığ. The diagnosis of PD was established through palpation of a penile plaque during physical examination and confirmed via superficial/color Doppler ultrasonography. To assess the three-dimensional shape of the penis during erection and determine the degree of curvature, all patients were asked to provide self-photographs. For patients unable to perform self-photography, an erection was induced in clinical settings via intracavernosal injection of a vasoactive agent, and curvature was subsequently measured using a goniometer. From each consenting participant in both groups, 5 mL of venous blood was collected, processed to separate plasma, and stored at –80°C. Serum levels of Relaxin, Phoenixin, and α-Klotho were analyzed at the Department of Medical Biochemistry, Firat University School of Medicine. The mean age and body mass index (BMI) of the patient group were 55.3±11.1 years and 26.8±3.2 kg/m², respectively, while those of the control group were 53±11.3 years and 25.4±3.4 kg/m². No significant differences were observed between the groups in terms of age and BMI (p>0.05). Mean serum Relaxin levels were significantly lower in the patient group compared to controls (37.7±8.9 vs. 47.7±13.4, p<0.01). Similarly, mean serum Phoenixin levels were lower in the patient group than in controls (31±7 vs. 39.2±12, p<0.01). However, mean serum α-Klotho levels were not significantly different between the patient and control groups (249.3±59.2 vs. 244.5±40.9, p>0.05). Pearson correlation analysis was performed to assess the relationships among these biomarkers. A very strong positive correlation was observed between Phoenixin and Relaxin (r>0.8), which was highly statistically significant (p<0.001). Additionally, α-Klotho demonstrated a moderate positive correlation with both Phoenixin and Relaxin (r>0.4), and both associations were statistically significant (p<0.01).