Alternatively Activated Macrophages are Associated with Prostate Volume and Lower Urinary Tract Symptoms Severity of Patients with Benign Prostate Hyperplasia

BACKGROUND: Recent studies show that alternatively activated macrophages (AAMs) are involved in tissue remodeling and fibrosis. However, the relationship between AAMs and the development of benign prostate hyperplasia (BPH) is unclear. The aim of this study is to investigate the correlation among AAMs, prostate volume, and lower urinary tract symptoms (LUTS) severity of benign prostate hyperplasia (BPH) patients. METHODS: Patients who underwent transurethral incision of the prostate (TUIP) for BPH were recruited and international prostatic symptom scores (IPSS) were assessed before the operations. Patients were divided into two groups: small (< 40  mL) and large prostate (≥ 40 mL) groups. Total macrophages (CD68) and AAMs (co-localization of CD68 and CD206) were analyzed by immunofluorescence. Prostate volume, post-voided residual volume (PVR), maximal (Qmax) and average (Qave) urinary flow rate were measured. We compared AAMs and clinical features between groups and analyzed the relationship of AAMs and these clinical parameters. RESULTS: A total of 42 patients diagnosed with BPH were recruited. The numbers of AAMs in prostate tissues of BPH patients with small prostate (n = 20) (5.15 ± 2.32 cells/HP) were significantly lower than those of large prostate (n = 22) (7.73 ± 2.83 cells/HP) (p < 0.05). Moreover, percentages of AAMs (AAMs/total macrophages) of small prostate patients (17.28 ± 6.62%) were lower than those of large prostate patients (23.30 ± 8.66%) (p < 0.05). Pearson's correlation analysis showed the numbers of AAMs were significantly positively correlated with prostate volume (r = 0.509, p < 0.01) and international prostatic symptom score (r = 0.344, p < 0.05). Percentages of AAMs were positively correlated with prostate volume (r = 0.447, p < 0.01). CONCLUSIONS: AAMs are associated the degree of BPH and the severity of LUTS, which indicates that AAMs may play an important role in development of BPH.