Effects of vitamin D supplementation on follicular development, gonadotropins and sex hormone concentrations, and insulin resistance in induced polycystic ovary syndrome

Consequences of vitamin D deficiency or overdosage on follicular development and steroidogenesis in Normo and hypo calcemic mouse models

Vitamin D deficiency (VDD) is a widespread situation, linked to patients' dietary habits and/or geographical origins. On the other hand, hypervitaminosis D (VDO) is also a worldwide problem, mainly associated with uncontrolled self-administration. In this study, we investigated the effects of VDD and VDO on sex steroid production and ovarian histology in mice. In addition to addressing the rarely explored situation of VDO, the originality of our approach is to disconnect VDD/VDO situations from the well-known calciotrophic effect of vitamin D (VitD). Our data indicate that VDD led to a significant decrease in serum LH and FSH levels, independently of serum calcium levels. VDD was also associated with increased testosterone and reduced oestradiol levels. VDO animals showed increased LH and reduced testosterone levels. Hormonal changes in the VDO animal groups were correlated with a lower accumulation of transcripts of steroidogenic genes such as CYP11A1 and 3ß-HSD, whereas these transcripts were higher in the VDD groups. CYP19A1 transcripts were lower in VDD animals than in controls. This study highlights the complex interaction between vitamin D status, the regulation of reproductive hormones and, consequently, reproductive performance. It underlines the need for caution when oral vitamin D supplementation is chosen as a therapeutic action to boost female reproductive performance, as VDO can be as detrimental as VDD.

1,25(OH)₂D₃ regulates androgen synthesis via transcriptional control of steroidogenic enzymes and LHR in the scented glands of muskrats (Ondatra zibethicus)

Photoperiodic changes induce seasonal variations in vitamin D3 levels, which can affect reproductive function. The muskrat, a seasonal breeder, possesses a pair of scented glands that secrete musky substances to attract mates. The scented glands can also synthesize androgens, which regulate their function through autocrine or paracrine signaling. This study aimed to investigate whether active vitamin D3 was synthesized locally and to explore how seasonal changes affected the specific mechanisms of androgen synthesis in the scented glands. The scented glands showed significant seasonal changes in morphology and histology. Transcriptomic analysis revealed that differentially expressed genes were enriched in pathways related to sex steroid hormone synthesis and calcium signaling. Quantitative analyses using qPCR and Western blotting demonstrated significant seasonal variations in the expressions of vitamin D3 receptors (VDR) and key synthetic and metabolic enzymes. Seasonal fluctuations in 1,25(OH)₂D₃ levels were positively correlated with the expressions of steroidogenic enzymes and androgen concentrations in the scented glands. Additionally, 1,25(OH)₂D₃ enhanced the expressions of steroidogenic enzymes in cultured primary cells. ChIP-seq analysis revealed that VD/VDR directly regulated the transcription of Cyp11a1, Cyp17a1, and Lhr by binding to their promoter regions. Furthermore, elevated androgen levels were observed when hCG was combined with 1 nM 1,25(OH)₂D₃. This study suggests that the scented glands can produce 1,25(OH)₂D₃ in autocrine or paracrine forms, with levels varying seasonally. VD/VDR enhanced androgen synthesis through a dual mechanism: (1) directly up-regulating the transcription of Cyp11a1 and Cyp17a1 to increase steroidogenic enzyme levels, and (2) indirectly promoting the expressions of steroidogenic enzymes by modulating Lhr transcription.

Natural compounds in the management of polycystic ovary syndrome: a comprehensive review of hormonal regulation and therapeutic potential

Polycystic ovary syndrome (PCOS) is a multifaceted endocrine disorder characterized by irregularities in gonadotropin secretion, hyperandrogenism, chronic anovulation, and polycystic ovarian morphology. In addition, it is often associated with metabolic dysfunctions, most notably insulin resistance (IR). This disorder affects approximately 6-20% of individuals, primarily emerging during early adolescence, and considerably increases the risk of conditions such as impaired glucose tolerance, type 2 diabetes, endometrial cancer, cardiovascular diseases, dyslipidemia, and postpartum complications. To date, there is no standardized protocol for treating PCOS. Existing therapies primarily rely on personalized pharmacotherapy and lifestyle modifications. However, these treatments may often lead to adverse effects, and most medications prescribed for PCOS are used off-label and have not secured approval from the U.S. Food and Drug Administration specifically for this condition. Recently, natural compounds have garnered considerable attention due to their efficacy in hormone modulation and minimal toxicity. Substances such as myo-inositol, resveratrol, berberine, and quercetin have shown promise in mitigating PCOS symptoms. Their multi-target properties offer the potential to achieve outcomes unattainable by single-target pharmaceuticals, particularly in managing heterogeneous conditions. This review aims to comprehensively analyze in vivo and in vitro research alongside clinical interventions to evaluate the influence of natural compounds on the prevalence of PCOS and their therapeutic potential. These investigations lay the groundwork for developing innovative therapeutic strategies for PCOS.

The Relationship Between the Average Decreased Times of Estradiol and Early Miscarriage: An Observational Study

Decreased estradiol (E2) levels are associated with early miscarriage (EM), but the relationship between decreased times of E2 and EM has not been reported. We aimed to investigate the relationship between the average decreased times of E2 (ADTE) and EM. Women with a history of miscarriage were retrospectively recruited from the Reproductive Center of Lanzhou University Second Hospital (Lanzhou, China) between September 2019 and February 2022. Based on pregnancy outcome, they were divided into ongoing pregnancy group (n = 359) and EM group (n = 104). In addition, subgroup analyses were performed for the number of previous miscarriages and whether E2 levels decreased continuously. The exposure and outcome variables were ADTE and miscarriage before 12 weeks of gestation, respectively. Totally, 1171 patients were recruited and 463 patients were finally analyzed. ADTE was associated with EM (odds ratio [OR] = 1.346, 95% confidence interval [CI]1.154-1.571, P < 0.001). When ADTE ≥ 2.5, the EM risk increased 1.17-fold compared to patients with 0-1.249 times (OR = 2.170, 95% CI 1.144-4.117, P = 0.018). Moreover, a threshold effect existed in the ADTE and the risk of EM with a value of 4.9 times. When exceeding 4.9 times, the EM risk increased 4.713-fold for each increased unit (OR = 5.713, 95% CI 1.255-23.170, P = 0.024). Subgroup analysis showed that ADTE had a greater effect on the occurrence of EM in women with a history of 1-2 miscarriages than in women with 3 miscarriages. Decreased E2 was a risk factor for EM regardless of whether it dropped continuously or not. In conclusion, our study identifies a potential link between ADTE and early miscarriage risk in women with prior miscarriages, yet cautious interpretation is necessary due to inherent design limitations. Further research with prospective designs and large population samples is essential to validate ADTE's utility as a predictive indicator for early miscarriage in clinical settings.

Effect of Vitamin D3 on Chemerin and Adiponectin Levels in Uterus of Polycystic Ovary Syndrome Rats

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrine disorder with disrupted uterus structure and function. A positive effect of vitamin D3 (VD3) in female reproduction was observed. Chemerin (RARRES2) and adiponectin (ADIPOQ) are the main adipokines whose levels are altered in PCOS patients. Therefore, the aim of this study was to investigate the impact of VD3 supplementation on RARRES2 and ADIPOQ levels in the uterus of PCOS rats.

METHODS

We analyzed the plasma levels and uterine transcript and protein expression of RARRES2 and ADIPOQ and their receptors (CCRL2, CMKLR1, GPR1, and ADIPOR1 and ADIPOR2, respectively) in rats with letrozole-induced PCOS.

RESULTS

In control animals, VD3 did not change plasma levels of both adipokines, while in PCOS rats supplemented with VD3, they returned to control levels. The expression of RARRES2 and all investigated receptors increased in the uterus of VD3-treated rats; however, the levels of Rarres2 and Gpr1 genes remained unchanged. VD3 supplementation decreased RARRES2, CMKLR1, and GPR1 but increased CCRL2 level to the control value. In the uterus of VD3-treated rats, the transcript and protein levels of ADIPOQ and both receptors ADIPOR1 increased. At the same time, VD3 supplementation induced an increase in Adipoq, Adipor1, and Adipor2 gene expression and restored protein levels to control level values.

CONCLUSIONS

our findings indicate a new mechanism of VD3 action in the uterine physiology of PCOS rats.

Vitamin D and calcium, together and separately, play roles in female reproductive performance

Vitamin D (VD) deficiency reduces the chances of successful fertilization; however, it remains to be validated whether this effect is dependent or not on calcium. To address this question, we generated several situation using a mouse model in which VD content was either increased or decreased in a normo or hypocalcemia context. After the measurement of serum 25-hydroxyvitamin D₂, calcium and phosphorus levels, an analysis was carried out in terms of oocytes maturation as well as reproductive performance. VD overdose, despite the fact that it resulted in an increased number of mature oocytes, reduced developmental competence and offspring survival. VD deficiency (VDD), on the contrary, reduced the number and percentage of mature oocytes, blastocyst rate, as well as fertility rate and offspring survival. Hypo-calcemia when VD levels were normal, had a similar effect than VDD. The effects of VDD were reversed by a diet that corrected calcium level. Therefore, both VD overdose (in a context of normal calcium level) VD deficiency as well as hypo-calcemia have an effect on female reproductive function. In conclusion, although closely related, VD and calcium act in part independently of each other in defining the “optimum” for female reproductive performance.

Vitamin D in follicular development and oocyte maturation

Vitamin D (VD) is a secosteroid hormone synthesized predominantly in the skin upon UV light exposure, which can also be obtained from dietary sources. In target cells, the bioactive VD binds to specific VD receptor to regulate downstream transcription of genes that are involved in a wide range of cellular processes. There is an increasing recognition that the proper physiological levels of VD are critical for optimizing reproductive potential in women. The direct VD action in the ovary was first suggested in the 1980s. Since then, research has attempted to determine the role of VD in follicular development and oocyte maturation in animal models and clinical settings. However, data published to date are inconclusive due to the complexity in VD metabolism and the fact that VD actions are pervasive in regulating physiological functions in various systems, including the reproductive, endocrine and nervous systems that control reproduction. This review summaries in vitro, in vivo, and clinical evidence regarding VD metabolism and signaling in the ovary, as well as VD-regulated or VD-associated ovarian follicular development, steroidogenic function, and oocyte maturation. It is suggested that adequate animal models are needed for well-controlled studies to unravel molecular mechanisms of VD action in the ovary. For clinical studies, follicular development and function may be evaluated more effectively in a relatively homogeneous patient population under a well-controlled experimental design. A comprehensive understanding of VD-regulated folliculogenesis and oogenesis will provide critical insight into the impact of VD in female reproductive health.

Effects of supraphysiological vitamin D3 (cholecalciferol) supplement on normal adult rat ovarian functions

This study measured the sequelae of cholecalciferol (VD₃) therapy on ovarian functions in adult VD-replete rats (n = 48). The animals were distributed into the control and VD groups following estrous cycle synchronisation. The VD group received VD₃ injections for 4 weeks (600 IU/Kg; 3 times/week). Vaginal cytology and cycle durations were recorded throughout the study. Serum VD (25-OH VD), Ca²⁺, gonadotrophins (FSH & LH) and sex steroids (E2 & progesterone) were measured following euthanasia. Follicles and corpora lutea were counted in ovarian tissue sections. VD receptor, binding protein, Ca²⁺-sensing receptor and retinoid X receptor-α genes and proteins were measured by quantitative RT-PCR and immunohistochemistry. Serum VD, LH, E2 and progesterone levels were significantly higher, whereas FSH declined, in the VD group than controls. VD₃ therapy was also associated with markedly higher rates alongside shorter durations of estrous cycles than controls. While serum Ca²⁺ levels were equal between the study groups, they correlated directly with serum 25-OH VD. The numbers of small and medium size ovarian follicles were equal in both study groups, whereas large follicles and corpora lutea counts were significantly higher in the VD group. The mRNAs and proteins of targeted molecules also increased substantially in the VD group than controls. In conclusion, treating VD-sufficient female rats with supraphysiological VD₃ supplements was not associated with hypercalcaemia, and could contribute to ovarian functions by regulating the hypothalamic-pituitary-ovarian hormones and ovarian VD-related molecules. However, further studies are still needed to illustrate the clinical significance of VD₃ in female reproduction.

Effects of Vitamin D Supplementation on Surrogate Markers of Fertility in PCOS Women: A Randomized Controlled Trial

Vitamin D (VD) might play an important role in polycystic ovary syndrome (PCOS) and female fertility. However, evidence from randomized controlled trials (RCT) is sparse. We examined VD effects on anti-Müllerian hormone (AMH) and other endocrine markers in PCOS and non-PCOS women. This is a post hoc analysis of a single-center, double-blind RCT conducted between December 2011 and October 2017 at the endocrine outpatient clinic at the Medical University of Graz, Austria. We included 180 PCOS women and 150 non-PCOS women with serum 25-hydroxyvitamin D (25(OH)D) concentrations <75 nmol/L in the trial. We randomized subjects to receive 20,000 IU of VD3/week (119 PCOS, 99 non-PCOS women) or placebo (61 PCOS, 51 non-PCOS women) for 24 weeks. Outcome measures were AMH, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, dehydroepiandrosterone sulfate, and androstenedione. In PCOS women, we observed a significant treatment effect on FSH (mean treatment effect 0.94, 95% confidence interval [CI] 0.087 to 1.799, p = 0.031) and LH/FSH ratio (mean treatment effect −0.335, 95% CI −0.621 to 0.050, p = 0.022), whereas no significant effect was observed in non-PCOS women. In PCOS women, VD treatment for 24 weeks had a significant effect on FSH and LH/FSH ratio but no effect on AMH levels.

Androgens and hirsutism score of overweight women with polycystic ovary syndrome improved after vitamin D treatment: A randomized placebo controlled clinical trial

BACKGROUND & AIM

The objective of this study was to investigate the effect of vitamin D treatment on androgen levels and hirsutism scores in overweight women with PCOS.

METHODS

A prospective, randomized, double-blind, placebo-controlled clinical study was conducted at King Abdullah University Hospital in Irbid, Jordan. Overweight Jordanian females aged 18-49 years with vitamin D deficiency and PCOS (n = 60) were assigned to two groups: the treatment group (n = 30) who received 50,000 IU per week of vitamin D₃ and the control group (n = 30) who received a placebo.

RESULTS

After receiving the treatment for 12 consecutive weeks, the levels of total testosterone, parathyroid hormone, free androgen index, and hirsutism score were significantly decreased (P < 0.001), and the levels of 25-hydroxyvitamin D (25(OH)D), sex hormone binding globulin, and phosphorus were significantly increased (P < 0.05). Furthermore, significant changes were observed in ovarian volume and follicle numbers and size ultrasonography, and in the regularity of the menstrual cycle (P < 0.001). In the placebo group, no significant changes were observed in either androgen levels, hirsutism score, or menstrual regularity.

CONCLUSION

Vitamin D₃ at a treatment dose of 50,000 IU per week improved 25(OH)D levels and decreased the hirsutism scores and androgen levels of overweight women with PCOS. These results could mean increased fertility and better reproductive health for overweight women with PCOS; the use of vitamin D₃ as a treatment for these patients should be further investigated. CLINICALTRIALS.

GOV REGESTRATION NUMBER

NCT02328404.

Assessing the effect of MitoQ10 and Vitamin D3 on ovarian oxidative stress, steroidogenesis and histomorphology in DHEA induced PCOS mouse model

Polycystic ovary syndrome (PCOS) continues to be one of the most complex reproductive and endocrine disorder among women of reproductive age. Recent reports have identified close interaction of Vitamin D deficiency and oxidative stress (OS) in exacerbating the pathophysiology of PCOS. This current study aims at assessing the combine effect of MitoQ₁₀ and Vitamin D3 on dehydroepiandrosterone (DHEA) induced PCOS. Following successful induction of PCOS using DHEA, mice were organized into five groups (n = 8) namely: Negative Control (NC), Vitamin D3 Vehicle (VDV), Vitamin D3 (VD), MitoQ₁₀ (MQ), Vitamin D3 plus MitoQ₁₀ (V+M) and DHEA, ethanol and distilled water, Vitamin D3, MitoQ₁₀ and Vitamin D3 plus MitoQ₁₀ were respectively administered for 20 consecutive days. The study also included positive control (PC) group (n = 8) in which no treatment was applied. Treatment effects were assessed using hormonal assays, biochemical assays, Real-Time PCR, western blotting and histological analysis. Combination of Vitamin D3 and MitoQ₁₀ significantly reduced levels of estradiol, progesterone, FSH, LH, LH/FSH, SOD and MDA. The expression rate of mRNAs of 3β-HSD, Cyp19a1, Cyp11a1, StAR, Keap1, HO-1 and Nrf2 were also significantly low in V+M group. Moreover, the histomorphological inspection of ovaries from this group revealed many healthy follicles at various stages of development including few atretic follicles, pre-antral and antral follicles and many corpora lutea. The characteristics observed in this group were in many ways similar to that of the PC group. The combination of MitoQ₁₀ and Vitamin D3 may be potential candidate to ameliorate PCOS.