Impact of high-risk and low-risk human papillomavirus infections on the male genital tract: effects on semen inflammation and sperm quality

Abstract

Human Papillomavirus (HPV), a prevalent sexually transmitted infection, comprises high-risk (HR-HPV) and low-risk (LR-HPV) viruses, the former posing a high risk for developing malignancies whereas the latter mainly for benign warts. Despite increasing awareness of HPV's impact on men's health, the influence of HR-HPV and LR-HPV urogenital infections on male fertility potential remains uncertain. This study aimed to investigate whether male urogenital infection with HR- or LR-HPV associates with impaired sperm quality, oxidative stress, and inflammation. A total of 205 male patients attending an urology clinic were enrolled. Semen samples were analyzed for HPV using PCR and genotyped by RFLP. Semen quality was evaluated following WHO guidelines. Semen leukocytes, reactive oxygen species (ROS), and sperm viability were analyzed using flow cytometry. HPV was detected in 19% (39/205) of semen samples. HR-HPV infections were more prevalent, with HPV-16 being the most frequent genotype. Neither HR-HPV nor LR-HPV were associated with significant alterations in routine sperm quality parameters. However, HR-HPV+ individuals showed significantly higher levels of sperm necrosis and exhibited increased proportions of ROS+ spermatozoa compared to LR-HPV+ or control individuals. Furthermore, no significant semen inflammation was detected in patients infected with either HR-HPV or LR-HPV, and unexpectedly reduced semen leukocytes and inflammatory cytokines (IL-6 and IL-1β) were observed in HR-HPV+ patients compared to controls. These observations underscore the importance of comprehensive HPV screening, including genotyping, in urology and fertility clinics to understand the progression of the infection, potential adverse effects on reproductive health, and the oncogenic risks involved.

Keywords: HPV; ROS; high-risk and low-risk HPV genotypes; male genital tract; semen cytokines.

Figure 1

HPV genotypes identified in men with HPV urogenital infection. The bar graph illustrates the number of cases of identified genotypes in the patient cohort under study, classified as intermediate to high oncogenic risk (HR-HPV, depicted in red) and low oncogenic risk (LR-HPV, represented in blue) genotypes using the PCR-RFLP technique. The proportion of unclassified HPV genotype(s) using this method is indicated as ‘Not Determined’ (ND, shown in gray).

Figure 2

Sperm quality from patients bearing high or low-risk HPV male urogenital infections and non-infected control individuals. Violin plots display (A–F) classic sperm quality parameters analyzed following the WHO 2010 criteria, (G–I) the type of sperm death (apoptosis/necrosis) assessed by AnV/PI staining and flow cytometry, (J) frequencies of Reactive Oxygen Species (ROS)-positive spermatozoa and (K) ROS-dependent mean fluorescence intensity (MFI) values in spermatozoa evaluated by flow cytometry using the Dcfh-DA probe. Dotted lines indicate median and interquartile ranges and, for semen analysis parameters, reference ranges are shown in light gray shading. Comparisons were made between the following groups: control individuals (gray) without leukocytospermia and negative for all analyzed uropathogens; HR-HPV patients (red): all HPV-positive patients bearing infections by intermediate or high oncogenic risk genotypes; LR-HPV patients (blue): all HPV-positive patients bearing infections by low oncogenic risk genotypes. Comparisons were performed between each group and the control group, and p-values were calculated using the Mann-Whitney test (*p<0.05, **p<0.01 and ***p<0.001, ****p<0.0001). ns, not significant.