Host genes regulate transcription of sperm-introduced hepatitis B virus genes in embryo

Hepatitis B virus infection, infertility, and assisted reproduction

BACKGROUND: Hepatitis B virus (HBV) is one of the most widespread viruses worldwide and a major cause of hepatitis, cirrhosis, and hepatocellular carcinoma. Previous studies have revealed the impacts of HBV infection on fertility. An increasing number of infertile couples with chronic hepatitis B (CHB) virus infection choose assisted reproductive technology (ART) to meet their fertility needs. Despite the high prevalence of HBV, the effects of HBV infection on assisted reproduction treatment remain limited and contradictory. OBJECTIVE: The aim of this study was to provide a comprehensive overview of the effect of HBV infection on fertility and discuss its effects on pregnancy outcomes, vertical transmission, pregnancy complications, and viral activity during ART treatment. METHODS: We conducted a literature search in PubMed for studies on HBV infection and ART published from 1996 to 2022. RESULTS: HBV infection negatively affected fertility in both males and females. Existing research shows that HBV infection may increase the risk of pregnancy complications in couples undergoing assisted reproduction treatment. The impact of HBV infection on the pregnancy outcomes of ART is still controversial. Current evidence does not support that ART increases the risk of vertical transmission of HBV, while relevant studies are limited. With the development of ART, the risk of HBV reactivation (HBVr) is increasing, especially due to the wide application of immunosuppressive therapy. CONCLUSIONS: Regular HBV infection screening and HBVr risk stratification and management are essential to prevent HBVr during ART. The determination of optimal strategy and timing of prophylactic anti-HBV therapy during ART still needs further investigation.

The influence of male HBV infection on sperm quality, embryonic development, and assisted reproductive outcomes

STUDY QUESTION

What is the impact of male hepatitis B virus (HBV) infection on sperm quality, embryonic development, and assisted reproductive outcomes?

SUMMARY ANSWER

Male HBV infection did not affect assisted reproductive outcomes, but HBV is capable of impairing human sperm and embryo formation in the early stages following fertilization.

WHAT IS KNOWN ALREADY

HBV is found in germ cells and early embryos of patients with HBV. HBV may impair human sperm function via increasing reactive oxygen species.

STUDY DESIGN, SIZE, DURATION

We conducted a retrospective cohort study of 1581 infertile couples, including 496 male patients clinically confirmed to have hepatitis B infection, and a laboratory study of effects of HBV proteins on early embryos, using human embryonic stem cells (hESCs), human sperm, and golden hamster oocytes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 1581 infertile couples (24-40 years of age) who were admitted to a reproductive medicine center to undergo ART for the first time from January 2019 to November 2021 were selected as the study subjects. The case group was composed of 469 couples with hepatitis B surface antigen (HBsAg)-seropositive men and seronegative women (368 for IVF and 101 for ICSI treatment). The negative control group was composed of 1112 couples where both men and women were seronegative for hepatitis B antigen. We divided these couples into three comparison groups (IVF/ICSI, IVF, and ICSI). IVF of human sperm and hamster oocytes was used to evaluate the influence of the HBV HBs protein on formation of 2-cell embryos. Mitochondrial membrane potential (MMP) of hESCs was assayed via a fluorescence intensity system. Immunofluorescence staining of the phosphorylated histone H2A.X was applied to identify DNA damage to hESCs caused by the HBV X (HBx) protein.

MAIN RESULTS AND THE ROLE OF CHANCE

Sperm concentration, total sperm number, and sperm with normal morphology were decreased in the couples with HBV-infected males in couples who were undergoing IVF/ICSI (male HBV(+) vs control: 469 vs 1112 individuals; sperm number, P < 0.01; normal sperm morphology, P < 0.01), IVF (368 vs 792; sperm number, P < 0.01; normal sperm morphology, P ≤ 0.05), and ICSI (101 vs 306; sperm number, P < 0.01; normal sperm morphology, P < 0.001). There was no significant difference in the number of embryo cleavages, blastocyst formation, biochemical pregnancy rate, clinical pregnancy rate, and live-birth rate between case and control groups. The 2PN fertilization rate in IVF/ICSI (P < 0.01) and ICSI (P < 0.05) couples, and the number of 2PN-fertilized oocytes in IVF (P < 0.001) couples were lower in couples with male HBV infection compared to control couples. HBV HBs protein reduced the MMP of human sperm and decreased 2-cell embryo formation in IVF of human sperm and zona-free-hamster oocyte. A reduction in fluorescence intensity and immunofluorescence staining of phosphorylated histone H2A.X indicated that HBx caused MMP impairment and DNA damage in human early embryonic cells, respectively.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

HBV can be examined in samples of sperm or discarded IVF early embryos from HBsAg-seropositive men and seronegative women. The hESC model in vitro may not fully mimic the natural embryos in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

This study furthers our understanding of the influence of male HBV infection on embryonic development. Our results suggest that a semen-washing process may be necessary for male patients with HBV undergoing ART to minimize the potential negative effects of HBV infection on the early embryo.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by grants from the National Natural Science Foundation of China, grant numbers 81870432 and 81570567 to X.Z., 81571994 to P.S., and 81950410640, the Natural Science Foundation of Guangdong Province, China (No. 2023A1515010660 to X.Z.), and the Li Ka Shing Shantou University Foundation (Grant No. L11112008). The authors have no conflicts of interest.

Host microRNAs regulate expression of hepatitis B virus genes during transmission from patients' sperm to embryo

Human sperm nucleus contains diverse RNA populations. This study aimed to screen and identify host microRNAs (miRs) that regulate gene expression of hepatitis B virus (HBV) during transmission from patients' sperm to sperm-derived embryos. Using microarrays, 336 miRs were found to be differentially expressed. After validation using real-time quantitative RT-PCR (RT-qPCR), four miRs were selected as targets. Using RT-qPCR and enzyme-linked immunosorbent assays, when patients' sperm were treated with mimics (or inhibitors) specific for hsa-miR-19a-3p and hsa-miR-29c-3p, the S gene transcription in sperm and translation in sperm-derived embryos was downregulated (or upregulated). There were significant differences in transcriptional and translational levels of the S gene between the test and control groups. These findings suggest that hsa-miR-19a-3p and hsa-miR-29c-3p significantly suppressed expression of the S gene, offering potential therapeutic targets for treating patients with HBV infection, and further reducing the negative impact of HBV infection on sperm fertilizing capacity.

Adverse effect of paternal hepatitis B virus infection on clinical pregnancy after frozen-thawed embryo transfer

PURPOSE

This study aimed to determine the effect of paternal hepatitis B virus (HBV) infection on reproductive outcomes of couples undergoing frozen-thawed embryo transfer (FET).

METHODS

This retrospective cohort study included FET cycles performed between January 2014 and March 2017 in couples with a hepatitis B surface antigen (HBsAg)-positive male partner and an HBsAg-negative female partner, which was categorized as HBsAg group. The FET cycles underwent by couples with both HBsAg-negative partners were randomly selected as controls. The primary outcome was clinical pregnancy.

RESULTS

A total of 117 FET cycles, comprising 39 in the HBsAg group and 78 in the control group, were included. Couples with HBsAg-positive male partners had significantly lower clinical pregnancy rate (17.9 vs 41.0%, P = 0.013), lower implantation rate (11.1 vs 24.5%, P = 0.014), and lower live birth rate (12.8 vs 30.8%, P = 0.034) compared with the control group. Moreover, the multivariate logistic regression analysis showed that paternal HBV infection was negatively associated with clinical pregnancy (odds ratio = 0.297, 95% confidence interval 0.108-0.817, P = 0.019). The miscarriage rate was not significantly different between the two groups (28.6 vs 25.0%, P = 1.000).

CONCLUSIONS

Paternal HBV infection resulted in a lower frequency of clinical pregnancy after FET, a difference that was probably attributed to a detrimental effect of HBV on the ability of embryos to survive freezing and thawing.