Content of alpha-tocopherol in blood serum of human Papillomavirus-infected women with cervical dysplasias

Effect of vitamin E supplementation on uterine cervical neoplasm: A meta-analysis of case-control studies

Several epidemiological studies have suggested that vitamin E could reduce the risk of uterine cervical neoplasm. However, controversial data were presented by different reports. Hence, we conducted a meta-analysis to assess the relationship between vitamin E and the risk of cervical neoplasia. We performed a comprehensive search of the PubMed, Embase and Cochrane databases through December 31, 2016. Based on a fixed-effects or random-effects model, the odds ratio (OR) and 95% confidence intervals (CIs) were calculated to assess the combined risk. Subgroup analyses and meta-regression were done to assess the source of heterogeneity. Subgroup analyses were performed according to survey ways, types of cervical neoplasia, study populations. A protocol was registered with PROSPERO (No. CRD42016036672). In total, 15 case-control studies were included, involving 3741 cases and 6328 controls. Our study suggested that higher category of vitamin E could reduce the cervical neoplasia risk (OR = 0.58, 95% CIs = 0.47–0.72, I² = 83%). In subgroup-analysis, both vitamin E intake and blood levels of vitamin E had a significant inverse association with the risk of cervical neoplasm. Additionally, we found the same relationship between vitamin E and cervical neoplasia among different populations and types of cervical neoplasia. Meta-regression showed that none of the including covariates were significantly related to the outcomes. No evidence of publication bias was observed. In conclusion, vitamin E intake and blood vitamin E levels were inversely associated with the risk of cervical neoplasia.

Effects of vitamin E on reproductive protection in pregnant mice infected with pseudorabies virus (PRV) via regulating expression of Toll-like receptors (TLRs) and cytokine balance

Vitamin E supplement and pseudorabies virus (PRV) infection have a reciprocal role in influencing the maternal immune response, a key determinant of the success or failure of pregnancy. However, it remains unknown whether vitamin E supplement provides protection against PRV-induced failure of pregnancy. This study was therefore conducted to investigate the effect of dietary vitamin E level (0, 75, 375, 750 and 1,500 mg/kg) on the reproduction performance, immunity and expression of Toll-like receptors (TLRs) of PRV-challenged mice. The mortality and abortion rate of PRV-challenged mice decreased with the increase in vitamin E consumption. Overall, PBS-injected mice had a higher live embryo number and live litter size than PRV-challenged mice. Both live embryo number and live litter size of PRV-challenged mice increased with increasing vitamin E levels. Vitamin E supplement resulted in decreased concentration of serum IL-2 and IFN-γ, but increased concentration of serum IL-10. The concentration of serum IgG, IgA and IgM increased with increasing vitamin E levels. In the uterine and embryo mRNA abundance of TLR3, TLR7 and TLR9 was higher in PRV-challenged mice than that in PBS-injected mice fed on the same dosage of vitamin E. The mRNA abundance of embryonic TLR3, TLR7 and TLR9 in PRV-challenged mice decreased with increasing vitamin E levels. Collectively, vitamin E supplement may improve reproductive performance of PRV-challenged mice by attenuating PRV-induced negative effects on the cytokine profile, immunoglobulin synthesis and TLR expression.

Vitamin or antioxidant intake (or serum level) and risk of cervical neoplasm: a meta-analysis

BACKGROUND

Case-control studies have reported the preventive effect of vitamin or antioxidant intake on cervical neoplasms such as cervical intraepithelial neoplasia (CIN) and invasive cervical cancer. However, the findings are inconsistent.

OBJECTIVE

To investigate quantitative effects of vitamin or antioxidant intake on cervical neoplasm using meta-analysis.

SEARCH STRATEGY

We searched PubMed, EMBASE and the Cochrane Library in November 2008. All articles searched were independently reviewed and selected by two evaluators according to predetermined selection criteria.

SELECTION CRITERIA

We included case-control studies reporting an association between vitamin or antioxidant intake (or serum level) and cervical neoplasm risk and reporting the adjusted odds ratios (OR) and 95% confidence intervals (CI), whenever possible.

DATA COLLECTION AND ANALYSIS

After retrieval of data from selected articles, we performed a meta-analysis using both fixed-effects and random- effects models.

MAIN RESULTS

Of 274 articles meeting our initial criteria, we included 22 case-control studies involving a total of 10,073 participants. In meta-analyses by type of vitamin or antioxidant, a significant preventive effect on cervical neoplasm was found in intakes of vitamin B12 (OR 0.35, 95% CI 0.19-0.63; n=2), vitamin C (OR 0.67, 95% CI 0.55-0.82; n=8), vitamin E (OR 0.56, 95% CI 0.35-0.88; n=10), and beta-carotene (OR 0.68, 95% CI 0.55-0.84; n=9).

AUTHORS' CONCLUSIONS

The findings of this meta-analysis indicate that overall, there were preventive effects of vitamin or antioxidant intake on cervical neoplasms in case-control studies.

[Human papillomavirus and cervical neoplasia]

Human papillomavirus (HPV) has been established as an important etiological factor for the development of cervical cancer. This DNA virus primarily infects the epithelium and can induce benign and malignant lesions of the mucous membranes and skin. Some HPVs are considered high risk due to their role in malignant progression of cervical tumors. Genital HPV infections are common and usually transient among young sexually active women. Only a small fraction of infected women develop cervical cancer, implying the involvement of environmental and genetic cofactors in cervical carcinogenesis. Classification, virology, pathology, natural history, epidemiological features of genital HPV infection, and future prospects for cervical cancer prevention with HPV vaccines will be reviewed here.

Chapter 4: Genital tract infections, cervical inflammation, and antioxidant nutrients--assessing their roles as human papillomavirus cofactors

Cervical infections by approximately 15 human papillomavirus (HPV) types are the necessary cause of cervical cancer and its immediate precursor lesions. However, oncogenic HPV infections are usually benign and usually resolve within 1-2 years. A few of these infections persist and progress to cervical precancer and cancer. A number of cervical factors, such as infection by sexually transmitted pathogens other than HPV, cervical inflammation, and antioxidant nutrients, may influence the natural history of HPV infection along the pathways of persistence and progression or resolution. We examine the possible roles of these HPV cofactors in cervical carcinogenesis and discuss new methodologies that may enable researchers to measure relevant markers of the cervical microenvironment in which these cofactors may be active.