Association of vitamin A deficiency with cervical squamous intraepithelial lesions in human immunodeficiency virus-infected women

Risk Factors for Cervical Cancer in Ghana

BACKGROUND

The major burden of cervical cancer occurs in low- and middle-income countries. In Ghana, it is the second most common cancer among women. Infection with high-risk human papilloma virus (HPV) has been established as the cause of cervical cancer. As such, it is important to identify risk factors that may affect progression from HPV infection to cancer.

AIMS

We assessed the risk factors assocaited with cervical cancer in Ghana.

METHODS

To identify the risk factors for cervical cancer, we conducted an unmatched case-control study in two hospitals in Ghana where most cervical cancer cases are diagnosed. Women with histologically confirmed cervical cancer were the cases, whereas women without cancer seeking care at the two hospitals were controls. A structured questionnaire was administered to the women, after which cervical samples were sent for HPV deoxyribonucleic acid (DNA) testing.

RESULTS

Overall, 206 cases and 230 controls were recruited. After adjusting for possible confounders, women with the highest educational level had a significantly lower risk of cervical cancer than those with no or little formal education. Parity was a major risk factor (odd ratio [OR] for five or more children = 7.9; 95% CI: 2.3-27.6), with risk increasing with increasing parity (p for trend <0.001). Women reporting the use of a homemade sanitary towel during menstruation also had an increased risk of cervical cancer compared with women who used a pad (OR: 7.3; 95% CI: 2.5-22.0).

CONCLUSION

In this Ghanaian population, high parity and poor personal hygienic conditions were the main contributing factors to the risk of cervical cancer after adjustment for the presence of high-risk HPV genotypes.

Retinoic acid metabolism in cancer: potential feasibility of retinoic acid metabolism blocking therapy

Retinoic acid (RA) is an active metabolite of vitamin A, which is an essential signaling molecule involved in cell fate decisions, such as differentiation, proliferation, and apoptosis, in a wide variety of cell types. Accumulated data have demonstrated that expression of RA-metabolizing enzymes, CYP26A1, B1, and C1 (cytochrome P450, family 26A1, B1, and C1, respectively), protects cells and tissues from exposure to RA through restriction of RA access to transcriptional machinery by converting RA to rapidly excreted derivatives. CYP26 enzymes play similar but separate roles in limiting the consequences of fluctuations in nutritional vitamin A. Recently, we found that RA depletion caused by expression of CYP26A1 promotes malignant behaviors of tumor cells derived from various tissues, implicating CYP26A1 as a candidate oncogene. We also showed that the expression levels of CYP26 enzymes are elevated in various types of cancer. We have provided evidence for oncogenic and cell survival properties of CYP26 enzymes, indicating that these molecules are possible therapeutic targets for CYP26-expressing malignancies.

HPV11E7 inhibits IMQ-induced chemokine and colony-stimulating factor production in keratinocytes

Imiquimod (IMQ) is approved as a first-line treatment for genital warts caused by human papillomavirus (HPV) infection. However, the recurrence rate is very high. HPV E7 protein plays a critical role in HPV immune escape. However, the role of HPV11 E7 protein in genital warts recurrence during IMQ treatment is not clear. Here, we found that the expression profile of NHEK cells was obviously changed after IMQ treatment, and a large number of genes encoding cytokines and genes involved in cytokine-mediated signaling pathways and cellular metabolic signaling pathways were up- or downregulated. HPV11E7 overexpression inhibited the IMQ-induced production of of multiple chemokines and colony-stimulating factors in NHEK cells. Furthermore, we found that HPV11E7 could impair the activation of mitogen-activated protein kinase (MAPK) signaling pathway. Therefore, our results suggested that HPV11 E7 diminishes the production of chemokines, colony-stimulating factors and other cytokines via inhibition of the MAPK signaling pathway, which suppresses the therapeutic effect of IMQ and promotes the recurrence of diseases, such as condyloma acuminatum.

How Dietary Deficiency Studies Have Illuminated the Many Roles of Vitamin A During Development and Postnatal Life

Vitamin A deficiency studies have been carried out since the early 1900s. Initially, these studies led to the identification of fat soluble A as a unique and essential component of the diet of rodents, birds, and humans. Continuing work established that vitamin A deficiency produces biochemical and physiological dysfunction in almost every vertebrate organ system from conception to death. This chapter begins with a review of representative historical and current studies that used the nutritional vitamin A deficiency research model to gain an understanding of the many roles vitamin A plays in prenatal and postnatal development and well-being. This is followed by a discussion of recent studies that show specific effects of vitamin A deficiency on prenatal development and postnatal maintenance of the olfactory epithelium, brain, and heart. Vitamin A deficiency studies have helped define the necessity of vitamin A for the health of all vertebrates, including farm animals, but the breadth of deficient states and their individual effects on health have not been fully determined. Future work is needed to develop tools to assess the complete vitamin A status of an organism and to define the levels of vitamin A that optimally support molecular and systems level processes during all ages and stages of life.

Retinoic acid-metabolizing enzyme cytochrome P450 26A1 promotes skin carcinogenesis induced by 7,12-dimethylbenz[a]anthracene

Elevated expression of the retinoic acid-metabolizing enzyme cytochrome P450 26A1 (CYP26A1) has been demonstrated to have an oncogenic function in carcinogenesis. In order to address the oncogenic capacity of CYP26A1 in vivo, transgenic mice that ubiquitously overexpressed CYP26A1 driven by the cytomegalovirus promoter were generated in the present study. Since the growth of these animals was normal for ≤15 months and they presented no evident abnormalities, a two-stage skin carcinogenesis analysis was performed. In the CYP26A1 transgenic mice, papilloma formation was observed within 7 weeks after administration of the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA). Development of papillomas in these animals was significantly accelerated when compared with that observed in the control mice following treatment with DMBA in combination with the chemical tumor promoter 12-O-tetradecanoylphorbol-13-acetate. In addition, constitutive expression of CYP26A1 increased the susceptibility of these mice to the generation of squamous cell carcinomas caused by treatment with the carcinogen alone. It is thus concluded that CYP26A1 expression promotes skin carcinogenesis initiated by DMBA.

Cellular retinoic acid bioavailability in various pathologies and its therapeutic implication

Retinoic acid (RA), an active metabolite of vitamin A, is a critical signaling molecule in various cell types. We found that RA depletion caused by expression of the RA-metabolizing enzyme CYP26A1 promotes carcinogenesis, implicating CYP26A1 as a candidate oncogene. Several studies of CYP26s have suggested that the biological effect of RA on target cells is primarily determined by "cellular RA bioavailability", which is defined as the RA level in an individual cell, rather than by the serum concentration of RA. Consistently, stellate cells store approximately 80% of vitamin A in the body, and the state of cellular RA bioavailability regulates their function. Based on the similarities between stellate cells and astrocytes, we demonstrated that retinal astrocytes regulate tight junction-based endothelial integrity in a paracrine manner. Since diabetic retinopathy is characterized by increased vascular permeability in its early pathogenesis, RA normalized retinal astrocytes that are compromised in diabetes, resulting in suppression of vascular leakiness. RA also attenuated the loss of the epithelial barrier in murine experimental colitis. The concept of "cellular RA bioavailability" in various diseases will be directed at understanding various pathologies caused by RA insufficiency, implying the potential feasibility of a therapeutic strategy targeting the stellate cell system.

Vitamin A Inhibits Development of Dextran Sulfate Sodium-Induced Colitis and Colon Cancer in a Mouse Model

Vitamin A is essential to mucosal immunity and cell differentiation. The fact that lack of it might involve chronic inflammation and increased risk of cancer has been reported. Little is known about the mechanism of vitamin A deficiency in the development of colitis and its influence on development of colorectal cancer. To determine the influence of vitamin A deficiency on colitis and colorectal cancer development, an experimental study using a colitis mouse model was performed. Dextran sulfate sodium (DSS) colitis was induced in vitamin A-deficient and vitamin A-supplemented mice. Further, colorectal carcinoma was induced by a combination of azoxymethane preinjection and DSS colitis. Results were compared between the two groups mainly by immunohistochemical analysis. Colitis was more severe and recovery from colitis was slower in vitamin A-deficient mice than in vitamin A-supplemented mice. Compared with vitamin A-supplemented mice, vitamin A-deficient mice had decreases in colonic subepithelial myofibroblasts and the ratio of mucosal IgA(+)/IgG(+) cells, increases in CD11c(+) dendritic cells, and a higher rate of development of colorectal carcinoma with colitis following azoxymethane. Vitamin A lipid droplets in subepithelial myofibroblasts were decreased in vitamin A-deficient mice, suggesting alterations in colonic crypt niche function. Thus, vitamin A inhibited colitis and the development of colorectal cancer.

Increased expression of the retinoic acid-metabolizing enzyme CYP26A1 during the progression of cervical squamous neoplasia and head and neck cancer

Background

Retinoic acid (RA) is a critical regulator of cell differentiation, proliferation, and apoptosis in various cell types. Recently, the RA-metabolizing enzyme CYP26A1 (cytochrome P450, family 26, subfamily A, polypeptide 1) has been shown to have an oncogenic function in breast carcinogenesis. However, the relevance of elevated CYP26A1 expression in human cancers remains to be clarified.

Methods

We immunohistochemically examined the expression of CYP26A1 in cervical squamous cell carcinoma (SCC) and its precursors, including low- and high-grade squamous intraepithelial lesions (LSIL and HSIL, respectively), as well as head and neck cancer (HNC). The association between CYP26A1 expression and a number of clinicopathological parameters was also evaluated.

Results

CYP26A1 was not expressed in normal cervical epithelium. CYP26A1 expression was present in LSIL but limited to basal and parabasal cells. HSIL cases exhibited strong nuclear expression of CYP26A1 and mixed cytoplasmic expression patterns with widely distributed expression toward the epithelial surface. Importantly, strong cytoplasmic staining of CYP26A1 was observed in 19 of 50 (38%) patients with cervical SCC. Elevated expression of CYP26A1 was significantly associated with younger age (<50 years) and lymph node involvement (pN). Similarly, CYP26A1 was not expressed in non-neoplastic tissues of the head and neck, but strong cytoplasmic staining of CYP26A1 was observed in 52 of 128 (41%) HNC cases. Such strong CYP26A1 expression was significantly associated with the primary tumor stage of carcinomas (pT) and the pathological tumor-node-metastasis (pTNM) stage in HNC.

Conclusion

Our results indicated an elevated CYP26A1 expression in malignant and precancerous dysplastic lesions of the human cervix, which also increased with the progression of cervical squamous neoplasia. In addition, this report is the first to demonstrate the increased expression of CYP26A1 in HNC and its significant correlation with primary tumor growth. These data suggested that CYP26A1 overexpression might contribute to the development and progression of cervical malignancies and squamous neoplasia of the head and neck.

Electronic supplementary material

The online version of this article (doi:10.1186/1756-0500-7-697) contains supplementary material, which is available to authorized users.

Oncogenic and cell survival properties of the retinoic acid metabolizing enzyme, CYP26A1

Vitamin A deficiency (VAD) is associated with increased susceptibility to carcinogenesis in animal models and elevated risk for a number of human cancers. Here, we found that CYP26A1, the gene encoding a cytochrome P450 enzyme specifically involved in metabolic inactivation of retinoic acid (RA), the most active vitamin A derivative, is highly expressed in 42% (27/65) of primary breast cancers. We also showed that enhanced expression of CYP26A1 suppresses cellular responses to anoikis and consequently promotes anchorage-independent growth. This transformed phenotype was sufficient to markedly increase tumorigenic and metastatic potential. Suppression of CYP26A1 significantly reversed the CYP26A1-mediated oncogenic characteristics, suggesting a direct link between intracellular RA status and tumorigenicity. Our observations provide strong evidence for oncogenic and cell survival properties of CYP26A1 in carcinogenesis, and suggest mechanisms whereby VAD might promote cancer development.

Women and HIV infection: the makings of a midlife crisis

With the advent of highly active antiretroviral agents, women with HIV infection can expect to live longer than ever before. This increased survival has led to concerns about the long-term implications of HIV disease and its treatment. Women with HIV infection appear to lose ovarian function earlier in life than women without HIV infection. They also have evidence of reduced bone mineral density and increased cardiovascular risk. Moreover, many of these increases in risk factors are present even prior to the menopausal transition. All of these risks, present at midlife, augur poorly for future health and describe a substantially increased burden of disease likely to accrue to HIV-infected women as they enter older age groups. Further compounding the adversity faced by the HIV infected, the demographics of women most vulnerable to this disease include adverse social and economic influences, both of which worsen their long-term prognosis. For example, drug use and poverty are related to more severe menopausal symptoms and chronic stress is related to worse psychological and cardiovascular risk. An understanding of how menopause interacts with HIV infection is therefore most important to alert the clinician to perform surveillance for common health problems in postmenopausal women, and to address directly and appropriately symptomatology during the menopausal transition.

Gynecologic issues in the HIV-infected woman

In this article, gynecologic conditions of increased importance in the HIV-infected woman are discussed. Women living with HIV may have an increase in menstrual disorders, lower genital tract neoplasias, gynecologic surgery, and sexually transmitted infections. The literature relevant to choosing a method of contraception for HIV-positive women is also discussed. With the advent of HAART, seropositive women are now facing issues around longevity, such as menopause and disorders of bone mineral density, as well as those associated with fertility.

Nutritional biomarkers associated with gynecological conditions among US women with or at risk of HIV infection

BACKGROUND

Women infected with HIV face a combination of health threats that include compromised nutrition and adverse gynecological conditions. This relation among HIV, nutrition, and gynecological conditions is complex and has rarely been investigated.

OBJECTIVE

Our objective was to investigate nutritional biomarkers associated with several gynecological conditions among US women with or at risk of HIV infection.

DESIGN

Data on 369 HIV-infected and 184 HIV-uninfected women with both nutritional and gynecological outcomes were analyzed from a cross-sectional nutritional substudy of the HIV Epidemiology Research Study (HERS). We examined micronutrient distributions comparing HIV-infected with HIV-uninfected participants and both subgroups with the US population. We then modeled the relation of 16 micronutrient serum concentrations to various gynecological conditions, producing partially adjusted odds ratios, adjusted for study site, risk cohort, and HIV status.

RESULTS

HIV-infected women's median antioxidant concentrations were lower than the medians of the US population. HERS women had lower median concentrations for vitamin A, selenium, and zinc irrespective of HIV status. Trichomoniasis prevalence was inversely related to serum alpha-carotene. Lower concentrations of vitamins A, C, and E and beta-carotene were associated with an increased risk of bacterial vaginosis. Higher concentrations of serum zinc were associated with lower risk of human papillomavirus. Candida colonization was higher among women with higher concentrations of total-iron-binding capacity.

CONCLUSION

We identified several significant associations of micronutrient concentrations with the prevalence of gynecological conditions. These findings warrant further investigation into possible causal relations.

Women's voices, women's choices: the challenge of nutrition and HIV/AIDS

The Society for International Nutrition Research sponsored a Symposium titled "Women's Voices, Women's Choices: The Challenge of Nutrition and HIV/AIDS in Asia and Africa" at Experimental Biology 2004 to highlight the challenges facing HIV-positive women living in resource-poor settings of Asia and Africa, when it comes to the everyday decisions they are forced to make about their own health and nutrition, and the health and the nutrition of their children. This introductory paper summarizes the rationale for this session, including a summary of the evidence for women's increased vulnerability to HIV, the nutritional impacts of HIV infection, and the special infant feeding and nutritional concerns facing HIV-positive pregnant and lactating mothers in Africa and Asia. The issue of nutrition and HIV/AIDS is addressed here from an intergenerational perspective, using new data from qualitative research, clinical trials, and behavioral interventions in India, Malawi, South Africa, Tanzania, and Zimbabwe, to illustrate important concerns, using study participants' own words to convey key messages. The focus is on women, because they are shouldering much of the burden of HIV infection in terms of their numbers and in their responsibilities for providing food and care for orphans and HIV-affected family members. Infant feeding choices are also considered in this review, because of the vast implications that not breast-feeding at all and stopping breast-feeding early have on the nutritional well-being of HIV-exposed children, as well as the positive contribution of breast-feeding to child nutrition and survival worldwide.

Human papillomavirus infection and disease in HIV-infected individuals

The possibility of increases in both oral and anogenital pathologic conditions due to human papillomavirus (HPV) in patients infected with the human immunodeficiency virus (HIV) is of concern and is the focus of numerous current research studies. HIV-infected women are at higher risk for cervical HPV detection, for infection with high-oncogenic-risk types of HPV, for persistent HPV infection, for cervical cytologic abnormalities, and for cervical intraepithelial neoplasms. HIV-infected men are at increased risk for anal HPV infection, for anal infection with high oncogenic-risk types of HPV, for persistent anal HPV infection, and for anal intraepithelial defects. Recent studies have shown an increased risk of oral warts in HIV-infected individuals despite treatment with highly active antiretroviral therapy (HAART). Oral HPV infection rates have not declined since the initiation of HAART, and evidence suggests that the rates may have actually increased in white HIV-infected males.

Gynecologic issues in the HIV-infected woman

Science has made great strides in understanding the management of the many gynecologic conditions that affect HIV-positive women with an increased frequency. As HIV-infected women's life expectancy continues to lengthen, new treatments are necessary for recurring conditions, such as lower genital tract neoplasias. The medical field has much to learn about the interaction between sex steroids, HIV-infection, and the immune system. As knowledge grows, clinicians will be better equipped to counsel women about contraceptive issues, pregnancy, and menopause.