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1.
Roles of Vitamin D in Reproductive Systems and Assisted Reproductive Technology.
Chen, Y, Zhi, X
Endocrinology. 2020;(4)
Abstract
Vitamin D, an essential steroid hormone in the human body, plays an important role in not only the regulation of calcium and phosphorus metabolism, but also in various physiological processes, such as cell differentiation and apoptosis, inflammation, and insulin resistance. Vitamin D receptors are widely distributed in male and female reproductive systems, suggesting that vitamin D is essential for fertility. Because vitamin D deficiency is highly prevalent around the world, this review aims to discuss the potential functions of vitamin D in male and female reproductive systems and the associations between vitamin D and assisted reproductive technology (ART) outcomes. Vitamin D is involved in many physiological reproductive processes, including steroidogenesis, spermatogenesis, and acrosome reaction. It is correlated with sperm quality, ovarian reserve, polycystic ovarian syndrome, and endometriosis, among others. Controversial clinical findings on vitamin D levels and ART outcomes were revealed in this review, and demonstrations of efficacy for human fertility in randomized controlled trials of vitamin D supplementation are notably lacking. Thus, further studies are highly required involving molecular mechanisms among different species and human populations, as well as randomized controlled trials.
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2.
The Relationship Between Female Reproductive Functions and Vitamin D.
Arslan, S, Akdevelioğlu, Y
Journal of the American College of Nutrition. 2018;(6):546-551
Abstract
Nonclassical target organs recently defined for vitamin D, a major regulator of calcium phosphorus homeostasis and bone health, include reproductive ones. This compilation study focuses on the potential effects of vitamin D on female reproductive functions. Vitamin D receptor enzymes that metabolize vitamin D are expressed in both central and peripheral reproductive organs. Most studies suggest that vitamin D may be directly or indirectly related to gonadal functions. Vitamin D's effects on reproductive functions may be indirectly related to diseases such as polycystic ovary syndrome (PCOS), uterine leiomyomas, and endometriosis. In case of vitamin D deficiency during infertility treatment, vitamin D supplementation can be recommended especially for women who have PCOS, insulin resistance, or low anti-Mullerian hormone levels. Supplementation, however, should take into account possible toxic effects of high-dose vitamin D. To be able to recommend measuring vitamin D as a routine screening test and to better understand the effects of vitamin D and its supplementation on female reproductive functions, larger randomized controlled prospective studies are needed.
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3.
Vitamin D receptor polymorphisms and the polycystic ovary syndrome: A systematic review.
Reis, GV, Gontijo, NA, Rodrigues, KF, Alves, MT, Ferreira, CN, Gomes, KB
The journal of obstetrics and gynaecology research. 2017;(3):436-446
Abstract
Polycystic ovary syndrome (PCOS) is the most frequent endocrinological disorder that affects women of reproductive age, leading to metabolic alterations, such as hyperandrogenism, obesity, menstrual irregularities, insulin resistance, and polycystic ovaries. The etiology remains unclear, but several genetic and environmental factors have been correlated with manifestations of this syndrome. Vitamin D plays important roles in metabolic pathways affected by PCOS, including calcium homeostasis, the insulin pathway, and sex hormone synthesis. Vitamin D concentration has been related with the severity of this disorder, and vitamin D receptor polymorphisms have been shown in some studies to have an association with some of the patterns presented by PCOS. The objective of this study is to provide an up-to-date review about vitamin D receptor polymorphisms and their association with PCOS.
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4.
VDR Gene variation and insulin resistance related diseases.
Han, FF, Lv, YL, Gong, LL, Liu, H, Wan, ZR, Liu, LH
Lipids in health and disease. 2017;(1):157
Abstract
BACKGROUND Vitamin D status may influence the risk of Insulin resistance related diseases such as Type 2 diabetes (T2DM), metabolic syndrome (MetS), and polycystic ovarian syndrome (PCOS). Several studies have assessed vitamin D receptor (VDR) gene polymorphism in relationship with these diseases; however, results remain inconsistent. Our study was conducted to elucidate whether VDR Gene polymorphisms could predict insulin resistance on a large scale. METHODS A meta-analysis using MEDLINE and EMBASE, was performed up to December 16th, 2016. Studies reporting association of vitamin D gene polymorphism with incident T2DM, MetS and PCOS outcomes were included and sub-group analysis by pigment of skin and latitude were performed. RESULTS A total of 28 articles based on four gene variation, and comprising 9232 participants with 5193 Insulin resistance related diseases patients were included. No significant associations of the VDR ApaI, BsmI, FokI and TaqI variant with Insulin resistance related diseases were found. However, sub-group analysis analysis showed that PCOS in TaqI (OR = 1.47, 95% CI = 1.03-2.09, P = 0.03) for T allele and MetS for G allele (OR = 1.41, 95% CI = 1.07-1.85, P = 0.01) in BsmI was significant association with VDR gene polymorphism. Simultaneously, sub-group analysis showed VDR ApaI rs7975232(G > T)variant was associated with insulin resistance related diseases in Asians (GG/GT + TT) (OR, 1.62; 95% CI, 1.03-2.53; P = 0.04) and population who lived in middle latitude district (30-60°) (GG/GT + TT) (OR, 1.22; 95% CI, 1.04-1.43; P = 0.02), VDR BsmI rs1544410 (A > G)and VDR Taq1rs731236 (T/C) variant were associated with insulin resistance related diseases in Caucasian (dark-pigmented). CONCLUSION The results suggested that the association between insulin resistance related diseases and VDR ApaI, BsmI, FokI variant was more obvious in dark-pigmented Caucasians and Asians but not in Caucasian with white skin.
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5.
The role of vitamin D in metabolic disturbances in polycystic ovary syndrome: a systematic review.
Krul-Poel, YH, Snackey, C, Louwers, Y, Lips, P, Lambalk, CB, Laven, JS, Simsek, S
European journal of endocrinology. 2013;(6):853-65
Abstract
CONTEXT Metabolic disturbances, in particular, insulin resistance (IR) and dyslipidemia, are common in women suffering from polycystic ovary syndrome (PCOS). Evidence is accumulating that vitamin D status may contribute to the development of metabolic disturbances in PCOS. OBJECTIVE The aim of this study was to carry out a systematic review addressing the association between vitamin D status, vitamin D receptor polymorphisms, and/or polymorphisms related to vitamin D metabolism and metabolic disturbances in women with PCOS. DESIGN AND METHODS A systematic search of electronic databases was carried out up to January 2013 for observational studies and clinical trials in women suffering from PCOS with outcome measures that were related to vitamin D status. We conducted univariate and multivariate regression analyses of the weighted means to gain insights into the association between vitamin D, BMI, and IR based on existing literature. RESULTS We found 29 eligible trials with inconsistency in their results. One well-designed randomized controlled trial has been carried out until now. Univariate regression analyses of the weighted means revealed vitamin D to be a significant and independent predictor of IR in both PCOS and control women. The significance disappeared after adjustment for BMI in PCOS women. CONCLUSIONS Current evidence suggests an inverse association between vitamin D status and metabolic disturbances in PCOS. Owing to the heterogeneity of the studies, it is hard to draw a definite conclusion. The causal relationship between vitamin D status and metabolic disturbances in PCOS remains to be determined in well-designed placebo-controlled randomized clinical trials.
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6.
Mineral metabolism abnormalities and vitamin D receptor activation in cardiorenal syndromes.
Ronco, C, Cozzolino, M
Heart failure reviews. 2012;(2):211-20
Abstract
Over the last decade, it has become increasingly clear that the cardiovascular and renal systems are interdependent. Primary disorders of either system have been shown to disturb the other system. As a result, a class of cardiorenal syndromes (CRS) has been identified wherein a vicious cycle is established as an acute/chronic dysfunction of either the kidney or the heart exacerbates the loss of function in the other organ. Progressive loss of kidney function observed in patients with CRS (mostly types 2 and 4) leads to reduced production of calcitriol (active vitamin D) and an imbalance in calcium and phosphorus levels, which are correlated with increased rates of cardiovascular events and mortality. In addition, hypocalcemia can lead to prolonged and excessive secretion of parathyroid hormone (PTH), eventually leading to development of secondary hyperparathyroidism. Therefore, based on this important mechanism of organ damage, one of the major goals of therapy for patients with CRS is to restore regulatory control of PTH. Although administration of calcitriol increases serum calcium levels and reduces PTH levels, it is also associated with elevated serum levels of calcium-phosphorus product. Therefore, compounds that selectively activate vitamin D receptors, potentially reducing calcium × phosphate toxicity, are likely to enhance cardiorenal protection and provide significant clinical benefit.