Document Type : Original Article
Authors
1 Department of Pathology, Shahid Sadoughi Hospital, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
2 Department of Internal Medicine, Shahid Sadoughi Hospital, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Abstract
Keywords
Human papillomavirus (HPV) infection is caused by a
DNA virus and it is considered the most common sexually
transmitted disease (STD) worldwide (
HPV may be found anywhere in the male reproductive
tract such as external genitalia, epididymis, vas deferens,
and urethra (
Sexually active couples who cannot achieve pregnancy
after one year are considered infertile. According to this
definition, approximately 15-20% of couples are infertile.
Despite the available advanced diagnostic methods, approximately
20-35% of infertile men have unexplained
infertility (
Evidence suggests that sexually transmitted infections
(STI) such as
In addition, HPV has been recently considered as an infectious
agent that affects fertility (
The prevalence of sperm infection by HPV is reported to be 2-31% in the general male population and 10-35% in men with unexplained infertility (
We conducted this case-control study on 70 infertile male patients and 70 confirmed fertile males who referred to Yazd Infertility Center in 2015. The Ethics Committee of Shahid Sadoughi University of Medical Sciences, Yazd, Iran approved this study (IR.SSU.MEDICINE.REC.1393.130) and all participants signed the study informed consent form. The major inclusion criterion of the case group was infertility after at least one year of unprotected sexual intercourse. The main exclusion criteria of the case group were as follows: chromosome abnormalities, azoospermia, undescended testis, and history of orchitis or varicocele. In addition, we excluded men whose spouses had histories of uterine and ovarian disorders. The control group included fertile men who had at least one child. The exclusion criterion of the control group was the presence of genital warts. The semen samples were collected and allowed to liquefy for 1 hour at 37°C. The spermogram was carried out for every specimen to determine semen parameters such as total sperm number, sperm motility, and morphology according to the World Health Organization (WHO) guidelines. Semen samples were immediately stored at -20°C until nucleic acid extraction and HPV detection.
The semen samples were centrifuged at 2500 rpm for 10 minutes. The supernatants were removed, and the pellets were transferred to Eppendorf tubes. DNA extraction was performed with a RIBO-prep Extraction Kit (AmpliSens, Russia) according to the manufacturer’s instructions. High-risk HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59 were detected using the AmpliSens® HPV HCR Screen-titre-FRT kit (AmpliSens, Russia) based on multiplex real-time polymerase chain reaction (PCR). The real-time PCR assays were performed using an ABI Step One Plus system (Applied Biosystems, Foster City, CA, USA). The reaction mixture in a total volume of 25 μl contained 10 μl of extracted DNA and 15 μl of the master mix according to the kit instructions. The conditions for real-time PCR assay consisted of an initial denaturation phase at 95ºC for 15 minutes followed by 60 cycles at 95ºC for 5 seconds, annealing at 60ºC for 20 seconds, and extension at 72ºC for 15 seconds.
General descriptive data of fertile and infertile men and the values of sperm parameters were presented as mean ± SD. Data were analysed using Stata statistical software, version 14 (StataCorp LLC, College Station, TX, USA). Univariate and multivariate logistic regression analysis were used for comparison of participant characteristics and sperm parameters between infertile and fertile men. Penalized logistic regression model with data augmentation was performed to compare the frequency of high-risk HPV DNA between infertile and fertile men (
A total of 140 men with an average age of 32.74 ± 5.21 years participated in the study. Table 1 summarizes the characteristics and sperm parameters for the fertile and infertile men. Data analysis according to logistic regression showed no statistically significant difference in fertility between smokers and nonsmokers (P=0.42). In addition, the results in Table 1 showed no significant correlation between education, length of marriage, and male infertility (P>0.05). Sperm parameters that included counts, total motility, progressive motility, and normal morphology rate in infertile men were significantly lower than the fertile group (
Penalized logistic regression analysis via data augmentation revealed a significant association between high-risk HPV infection and male infertility (
Characteristics of participants and sperm parameters in the total study population
Characteristics/parameters | Fertile men n=70 | Infertile men n=70 | OR adjusted | 95% CI | P valuea | |
---|---|---|---|---|---|---|
Mean age (Y ± SD) | 33.61 ± 5.25 | 31.88 ± 5.18 | 1.6 | 1.23-2.36 | 0.99 | |
Education n (%) | ||||||
Illiterate | 2 (1.4) | 1 (0.7) | 0.37 | 0.27-3.12 | 0.61 | |
Primary | 6 (4.3) | 4 (2.9) | 0.59 | 0.47-1.78 | 0.46 | |
Secondary | 23 (16.4) | 18 (12.9) | 0.71 | 0.39-1.13 | 0.37 | |
College | 39 (27.8) | 47 (33.6) | 1 | - | Reference | |
Married period (Y) | 5.96 ± 4 | 5.73 ± 4.46 | 0.93 | 0.77-1.12 | 0.43 | |
Smoking (%) | 17 (24.3) | 23 (32.9) | 0.68 | 0.49-1.14 | 0.42 | |
Sperm count (million/ml) | 93.50 ± 37.95 | 59.64 ± 30.21 | 1.01 | 0.95-0.98 | 0.021 | |
Sperm motility (%) | 59.39 ± 8.86 | 31.21 ± 14.04 | 1.05 | 0.80-0.89 | 0.042 | |
Sperm progressive motility (%) | 37.54 ± 17.08 | 6.09 ± 5.20 | 1.06 | 0.64-0.82 | 0.016 | |
Normal sperm morphology rate (%) | 40.10 ± 9.48 | 14.26 ± 11.45 | 1.03 | 0.78-0.88 | 0.031 | |
HPV DNA infection of semen | 0 | 8 (11.43) | 0.1 | 0.01-0.82 | 0.03b | |
Data are presented as mean ± SD or n (%). HPV; Human papillomavirus, OR; Odds ratio, CI; Confidence interval, a; P value obtained by univariate and multivariate logistic regression analysis, and b; P value obtained by penalized logistic regression model via data augmentation.
Comparison of sperm parameters between infertile men infected with HPV and the HPV-negative group
Sperm parameters | HPV positive | HPV negative | P valuea |
---|---|---|---|
Sperm count (million/ml) | 51.38 ± 29.29 | 60.71 ± 30.39 | 0.41 |
Sperm motility (%) | 23.50 ± 13.50 | 32.21 ± 13.90 | 0.04 |
Sperm progressive motility (%) | 0.63 ± 1.77 | 6.79 ± 5.08 | <0.001 |
Normal sperm morphology rate (%) | 7.13 ± 2.64 | 15.18 ± 11.83 | <0.001 |
Sperm parameters are presented as mean ± SD. HPV; Human papillomavirus and a; Pvalue obtained by independent samples t test.
The effect of HPV on sperm quality and male infertility is controversial. Results of the current study have indicated that seminal high-risk HPV in infertile men was higher than in the fertile men, and it could impair sperm quality. These data suggested a possible role for HPV in male infertility. We found an HPV infection prevalence of 11.43% in semen of men who suffered from infertility. Previous studies have also reported a prevalence of HPV in infertile men that ranged from 10 to 30% (
Some STI impair semen quality by inducing epididymitis, orchitis or urethritis (
In the present study, the normal sperm morphology rate in HPV-positive cases significantly decreased compared with its rate in HPV-negative men. Several studies reported no difference in sperm morphology between HPV-infected and noninfected infertile men (
In this study, high-risk HPV infection did not significantly affect total sperm count in infertile men. Rintala et al. obtained similar results from infertile men infected with high-risk types of HPV (
The limitation of our study included the absence of data on volume and pH of semen, which was not obtained in each semen analysis. However, most previous studies have not reported any connection between seminal HPV infection and alteration in these parameters (
Taken together, the result of the present study indicated that HPV could be a risk factor for male infertility. The prevalence of high-risk HPV in infertile men was significantly higher than fertile men. HPV decreased sperm motility and normal morphology rate. Further, larger studies would be required to confirm the impact of HPV on male infertility.