Reproductive defects are corrected in vitamin d-deficient female rats fed a high calcium, phosphorus and lactose diet

Serum Vitamin D Concentrations, Time to Pregnancy, and Pregnancy Outcomes among Preconception Couples: A Cohort Study in Shanghai, China

BACKGROUND

The role of vitamin D in reproductive health is still unclear. This study aimed to assess the effect of serum 25-hydroxyvitamin D (25(OH)D), among preconception couples, on fecundity, and the associations between 25(OH)D concentrations before and during pregnancy, and pregnancy outcomes.

METHODS

200 preconception couples attempting to conceive were recruited and were followed-up until childbirth. Time to pregnancy was collected via telephone every two months or obtained via a questionnaire during pregnancy. Blood samples were collected to measure serum 25(OH)D levels from both partners at enrollment and from women during the second and third trimester of pregnancy.

RESULTS

Couples had higher conception rates within six months (adjusted odds ratio (aOR): 3.72, 95% CI: 1.16, 11.9) and reduced time to pregnancy (adjusted fecundability ratio (aFR): 1.50, 95% CI: 1.01, 2.23) if male partners had sufficient 25(OH)D compared with insufficient 25(OH)D. Compared to pregnant women with insufficient 25(OH)D in the third trimester of pregnancy, sufficient 25(OH)D was associated with reduced odds of anemia (OR: 0.22, 95% CI: 0.06, 0.82), longer gestational age (β: 0.53, 95% CI: 0.04, 1.01) and newborns' higher ponderal index (β: 0.10, 95% CI: 0.01, 0.19).

CONCLUSIONS

Sufficient serum 25(OH)D levels among preconception men or during pregnancy were associated with better reproductive health.

Seasonal dynamic of cholecalciferol (D3) and anti-Muellerian hormone (AMH) with impact on ovarian response and IVF/ICSI

OBJECTIVE

Recent studies revealed intriguing associations between cholecalciferol (D3) and reproductive functions. Seasonal changes of D3 concentrations are well known; however, they are not always considered in the context of reproductive functions. In this study, we analyzed D3 serum concentration in IVF/ICSI patients with respect to seasonal 3-month quartiles and anti-Muellerian hormone (AMH) referring to the impact on Assisted Reproductive Technologies (ART) outcome.

MATERIALS AND RESEARCH METHODS

We studied 469 female patients, presenting between 2012 and 2018 for ART treatment in our fertility center. D3 as well as the AMH serum concentrations were measured at the beginning of the follicle stimulation (days 3-5 of menstrual cycles). Results were evaluated with respect to seasonal quartiles and outcome of the ART cycles.

RESULTS

D3 concentrations showed significant fluctuations within annual quartiles with a pronounced peak in August-October and a minimum in February-April (26.0 vs. 20.5 mg/dl; p < 0.0001). Similar seasonal dynamics were found for AMH (2.98 vs. 1.78 ng/ml; p = 0.010) and these were associated with significantly shorter stimulation periods during August-October (11.29 vs. 12.12 days; p = 0.042), higher number of fertilized oocytes between August and October (6.23 vs. 4.97; p = 0.05) along with a trend towards higher numbers of cumulus-oocyte complexes. However, no such differences were found for the numbers of MII oocytes or pregnancy rates.

CONCLUSION

Our data indicate seasonal 3-month quartile variations of AMH concentrations and characteristics of ART, such as days of ovarian stimulation and number of fertilized oocytes. Highest AMH concentrations were found between August and October and this quartile was associated with highest D3 concentrations.

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.

The combination of smoking with vitamin D deficiency impairs skeletal muscle fiber hypertrophy in response to overload in mice

Vitamin D deficiency, which is highly prevalent in the general population, exerts similar deleterious effects on skeletal muscles to those induced by cigarette smoking. We examined whether cigarette smoke (CS) exposure and/or vitamin D deficiency impairs the skeletal muscle hypertrophic response to overload. Male C57Bl/6JolaH mice on a normal or vitamin D-deficient diet were exposed to CS or room air for 18 wk. Six weeks after initiation of smoke or air exposure, sham surgery or denervation of the agonists of the left plantaris muscle was performed. The right leg served as internal control. Twelve weeks later, the hypertrophic response was assessed. CS exposure instigated loss of body and muscle mass, and increased lung inflammatory cell infiltration (P < 0.05), independently of diet. Maximal exercise capacity, whole body strength, in situ plantaris muscle force, and key markers of hypertrophic signaling (Akt, 4EBP1, and FoxO1) were not significantly affected by smoking or diet. The increase in plantaris muscle fiber cross-sectional area in response to overload was attenuated in vitamin D-deficient CS-exposed mice (smoking × diet interaction for hypertrophy, P = 0.03). In situ fatigue resistance was elevated in hypertrophied plantaris, irrespective of vitamin D deficiency and/or CS exposure. In conclusion, our data show that CS exposure or vitamin D deficiency alone did not attenuate the hypertrophic response of overloaded plantaris muscles, but this hypertrophic response was weakened when both conditions were combined. These data suggest that current smokers who also present with vitamin D deficiency may be less likely to respond to a training program.NEW & NOTEWORTHY Plantaris hypertrophy caused by compensatory overload after denervation of the soleus and gastrocnemius muscles showed increased mass and fiber dimensions, but to a lesser extent when vitamin D deficiency was combined with cigarette smoking. Fatigue resistance was elevated in hypertrophied plantaris, irrespective of diet or smoking, whereas physical fitness, hypertrophic markers, and in situ plantaris force were similar. These data showed that the hypertrophic response to overload is attenuated when both conditions are combined.

Pre-conception 25-hydroxyvitamin D (25(OH)D) and fecundability

STUDY QUESTION

Is pre-conception 25(OH)D associated with the per cycle probability of conception, i.e fecundability, in a prospective cohort study?

SUMMARY ANSWER

There are suggestive associations of high 25(OH)D (at least 50 ng/ml) with increased fecundability and low 25(OH)D (<20 ng/ml) with reduced fecundability, but the estimates were imprecise.

WHAT IS KNOWN ALREADY

Vitamin D has been associated with reproductive function and fertility in animal studies, but few human studies exist.

STUDY DESIGN, SIZE, DURATION

This community-based prospective cohort study included 522 women attempting to become pregnant between 2010 and 2016. The women completed online daily and monthly diaries until a positive home pregnancy test was observed or 12 months had elapsed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included women from central North Carolina who were aged 30-44 with no history of infertility, with no more than 3 months of attempt time at recruitment. Women recorded vaginal bleeding so that the ongoing number of attempt cycles could be counted and used to quantify a woman's pregnancy attempt time. Blood collected at the study entry was analysed for 25(OH)D using liquid chromatography tandem mass spectrometry. Associations with fecundability were estimated with a log-binomial discrete time-to-event model.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 522 women, 257 conceived during the study. The mean age was 33 years and the mean 25(OH)D was 36 ng/ml. There was an estimated 10% higher fecundability with each 10 ng/ml increase in 25(OH)D (fecundability ratio (FR) 1.10, 95% CI: 0.96, 1.25). The suggestive dose-response association with the continuous measure of 25(OH)D was driven by women in the lowest and the highest categories of 25(OH)D. Compared to women with 25(OH)D of 30-40 ng/ml, women below 20 ng/ml had an estimated 45% reduction in fecundability (FR (CI): 0.55 (0.23, 1.32)), and women with at least 50 ng/ml had an estimated 35% increase in fecundability (FR (CI): 1.35 (0.95, 1.91)). Across these three categories (25(OH)D of <20 ng/ml, 30-40 ng/ml and > 50 ng/ml), the probability of taking longer than 6 months to conceive was, respectively, 51% (17%, 74%), 28% (17%, 39%) and 15% (10%, 37%).

LIMITATIONS, REASONS FOR CAUTION

While the distribution of 25(OH)D was wide, the number of observed cycles with high 25(OH)D (N = 107) or low 25(OH)D (N = 56) was small.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings are consistent with prior reports of reduced fertility in women with 25(OH)D concentrations below the clinically defined deficiency level (20 ng/ml). Further studies are needed to evaluate the possible reproductive benefits of considerably higher 25(OH)D concentration (>50 ng/ml).

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (NIH) under award numbers R00HD079659 and R01HD067683 and supported in part by the Intramural Research Program of the National Institute of Environmental Health Sciences, under projects ES103086, ES049003 and ES044003. ClearBlue ovulation predictor kits were generously donated to AMZJ and AJW by Swiss Precision Diagnostics. Drs Wilcox and Jukic report non-financial support from Swiss Precision Diagnostics during the conduct of the study; Dr Jukic reports non-financial support from Theralogix, LLC, outside the submitted work. Otherwise there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Airway infection with Nontypeable Haemophilus influenzae is more rapidly eradicated in vitamin D deficient mice

Chronic obstructive pulmonary disease (COPD), which is characterized by an excessive inflammatory response of the airways, is often complicated by exacerbations. Vitamin D deficiency has been associated with an increased risk for COPD and may predispose COPD patients to a higher exacerbation rate, particularly during smoking. In the current study, we investigated the effect of vitamin D deficiency and cigarette smoke (CS)-exposure on lung inflammation and bacterial clearance after an acute infection with Nontypeable Haemophilus influenzae (NTHi). Vitamin D deficient or sufficient mice were exposed to nose-only CS or ambient air for 6 weeks and oropharyngeally instilled with 10⁶ NTHi. Residual viable NTHi were measured at different time points post-infection. Mechanisms of bacterial clearance (e.g. phagocytosis, pattern recognition receptors, antimicrobial peptides, surfactant proteins and mucin) and lung remodeling (e.g. metalloproteinases, MMP's) were assessed. Although smoking resulted in reduced phagocytosis capacity of macrophages and neutrophils, bacterial clearance was similar to control mice. By contrast and independent of smoking, bacterial clearance was significantly accelerated in vitamin D deficient mice already from 24 h post-infection (p = 0.0087). This faster and complete eradication was associated with a more rapid resolution of cytokines and neutrophils 72 h post-infection and dominated by an upregulation of cathelicidin-related antimicrobial peptide (CRAMP) mRNA during infection (p = 0.026). However, vitamin D deficiency also resulted in more MMP12 protein in broncho-alveolar lavage and a shift in mRNA expression of MMP12/TIMP1 (p = 0.038) and MMP9/TIMP1 (p = 0.024) ratio towards more protease activity. Overall, vitamin D deficient mice resolved NTHi infection faster with a faster resolution of local lung inflammation, possibly through upregulation of CRAMP. This was associated with a disruption of the protease/anti-protease balance, which may potentially scale towards a higher extracellular matrix breakdown.

Do Serum Vitamin D Levels Have Any Effect on Intrauterine Insemination Success?

BACKGROUND

Recent studies have shown that vitamin D has an essential role in the reproductive system. In this study, we aimed to investigate the effect of vitamin D levels in patients undergoing ovulation induction (OI), and subsequent intrauterine insemination (IUI) procedure.

MATERIALS AND METHODS

One hundred and four infertile and one hundred and three fertile women were recruited in this cross-sectional study which was conducted in a tertiary level maternity hospital. Infertile patients were divided into pregnant and non-pregnant subgroups after treatment. Individual characteristics and 25-hydroxyvitamin D3 [25 (OH) D3] levels were compared between the groups.

RESULTS

The vast majority of our study population consisted of women who had vitamin D deficiency (96.6%). There was no statistically significant difference between infertile and fertile groups in terms of serum 25 (OH) D3 levels (P=0.512). Similarly, no significant difference was observed between the pregnant and non-pregnant subgroups of infertile patients regarding 25 (OH) D3 levels (P=0.267).

CONCLUSION

There is no association between female infertility and serum vitamin D levels. Vitamin D does not predict pregnancy in infertile women undergoing OI with IUI. Further research which will provide a comparison between much more women who have deficient and sufficient 25 (OH) D3 levels is warranted.

Vitamin D is associated with bioavailability of androgens in eumenorrheic women with prior pregnancy loss

BACKGROUND

Prior studies have reported mixed results regarding relationships between vitamin D, androgens, and sex hormone-binding globulin in patients with polycystic ovary syndrome. However, less is known regarding these associations in eumenorrheic, premenopausal women.

OBJECTIVE

Our objective was to study the relationships between serum vitamin D and androgen biomarkers in eumenorrheic women with a history of pregnancy loss who were attempting pregnancy.

STUDY DESIGN

This was an analysis of a cohort of 1191 participants from the Effects of Aspirin in Gestation and Reproduction trial (2006-2012). Participants were attempting to conceive, aged 18-40 years, with 1-2 documented prior pregnancy losses and no history of infertility, and recruited from 4 academic medical centers in the United States. Serum vitamin D (25-hydroxyvitamin D) and hormone concentrations were measured at baseline.

RESULTS

Vitamin D concentration was negatively associated with free androgen index (percentage change [95% confidence interval, -5% (-8% to -2%)] per 10 ng/mL increase) and positively associated with sex hormone-binding globulin (95% confidence interval, 4% [2-7%]), although not with total testosterone, free testosterone, or dehydroepiandrosterone sulfate after adjusting for age, body mass index, smoking status, race, income, education, physical activity, and season of blood draw.

CONCLUSION

Overall, vitamin D was associated with sex hormone-binding globulin and free androgen index in eumenorrheic women with prior pregnancy loss, suggesting that vitamin D may play a role in the bioavailability of androgens in eumenorrheic women. We are limited in making assessments regarding directionality, given the cross-sectional nature of our study.

Vitamin D, the placenta and early pregnancy: effects on trophoblast function

Pregnancy is associated with significant changes in vitamin D metabolism, notably increased maternal serum levels of active vitamin D, 1,25-dihydroxyvitamin (1,25(OH)₂D). This appears to be due primarily to increased renal activity of the enzyme 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1) that catalyzes synthesis of 1,25(OH)₂D, but CYP27B1 expression is also prominent in both the maternal decidua and fetal trophoblast components of the placenta. The precise function of placental synthesis of 1,25(OH)₂D remains unclear, but is likely to involve localized tissue-specific responses with both decidua and trophoblast also expressing the vitamin D receptor (VDR) for 1,25(OH)₂D. We have previously described immunomodulatory responses to 1,25(OH)₂D by diverse populations of VDR-expressing cells within the decidua. The aim of the current review is to detail the role of vitamin D in pregnancy from a trophoblast perspective, with particular emphasis on the potential role of 1,25(OH)₂D as a regulator of trophoblast invasion in early pregnancy. Vitamin D deficiency is common in pregnant women, and a wide range of studies have linked low vitamin D status to adverse events in pregnancy. To date, most of these studies have focused on adverse events later in pregnancy, but the current review will explore the potential impact of vitamin D on early pregnancy, and how this may influence implantation and miscarriage.

Prevalence of vitamin D deficiency in girls with idiopathic central precocious puberty

The relationship between vitamin D deficiency and idiopathic central precocious puberty (ICPP) has been recently documented. In this study, 280 girls diagnosed with ICPP and 188 normal puberty control girls of similar ages were enrolled and retrospectively studied. The ICPP group had significantly lower serum 25-hydroxyvitamin D (25[OH]D) levels than the control group. Furthermore, a nonlinear relationship was found between serum 25[OH]D and ICPP, and a cut-off point for serum 25[OH]D was found at 31.8 ng/ml for ICPP with and without adjusting the different confounding factors. Girls with serum 25[OH]D ≥ 31.8 ng/ml had a lower odds ratio (unadjusted: OR 0.36, 95% CI 0.15 to 0.83, P < 0.05; height and weight adjusted: OR 0.44, 95% CI 0.18 to 1.08, P = 0.072; BMI adjusted: OR 0.36, 95% CI 0.16 to 0.84, P < 0.05). The ICPP subjects with 25[OH]D deficiency had a higher body mass index (BMI) than the subjects from the two other subgroups. Correlation analysis showed that vitamin D level is correlated with BMI and some metabolic parameters in the ICPP group. Our study suggested that vitamin D status may be associated with ICPP risk and may have a threshold effect on ICPP.

Vitamin D Deficiency Does Not Influence Reproductive Outcomes of IVF-ICSI: A Study of Oocyte Donors and Recipients

Background:

Vitamin D and its active metabolite, 1,25-dihydroxy vitamin D (1,25-(OH)₂D₃), play a significant role in reproduction.

Aim:

To assess the effect of serum 25-hydroxy vitamin D level on oocyte quality and endometrial receptivity by studying oocyte donors and their recipients.

Materials and Methods:

This prospective study consisted of two groups: Group A (recipient group) and Group B (donor group). All the participants of Groups A1 and B1 as well as Groups A2 and B2 were subcategorized into vitamin D-deficient (<20 ng/mL) and vitamin D replete-insufficient (20 to ≥30 ng/mL), respectively.

Results:

In the recipient group, out of the 192 participants, 123 were in A1 group, and 69 were in A2 group. In donor group, out of the 99 participants, 54 were in B1 group, and 45 in B2 group. In the recipient group, Group A2 had a higher clinical pregnancy rate, implantation rate and ongoing pregnancy rate, and a lower abortion rate as compared to that of A1, but these are statistically insignificant. The difference in endometrial thickness and number of embryos transferred between both groups was insignificant. In the donor group, the total number of days of controlled ovarian hyperstimulation, the dose of gonadotropins, the number of oocytes retrieved, the percentage of mature oocytes, and the percentage of usable embryos were higher in Group B2 than those in Group B1, but these are statistically insignificant. The fertilization rate was statistically insignificant between Groups B1 and B2.

Conclusion:

Vitamin D deficiency leads to lower reproductive outcomes, though not statistically significant and, thereby, does not have a negative influence on in-vitro fertilization–intracytoplasmic sperm injection outcomes.

Vitamin D3 deficiency is associated with female sexual dysfunction in premenopausal women

PURPOSE

To assess female sexual functions in women who were affected by vitamin D₃ deficiency.

METHODS

A total of 50 women with FSD and 58 healthy women controls were included in the study, according to the Female Sexual Function Index (FSFI) questionnaire using a 26.55 cutoff value. Detailed medical histories were obtained from all sexual active women, and all women were evaluated in terms of possible presence of depression with the Beck Depression Inventory (BDI). Serum 25-hydroxyvitamin D₃, follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, total and free testosterone, estradiol, dehydroepiandrosterone-SO₄ (DHEA-SO₄), sex hormone-binding globulin (SHBG), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) levels were measured.

RESULTS

Mean age of premenopausal women was 34.9 ± 6.3 years. The level of serum 25-hydroxyvitamin D₃ was significantly lower in women with FSD compared with the controls (15.9 ± 8.4 and 26.3 ± 11.7 nmol/L, respectively). Desire (p = 0.0001), arousal (p = 0.0001), lubrication (p = 0.002), orgasm (p = 0.0001), satisfaction (p = 0.018), and pain (p = 0.010) domain scores were also correlated with the levels of serum 25-hydroxyvitamin D₃. The BDI score showed a significant negative correlation with the total FSFI score (r = -0.492, p = 0.0001). The FSFI score not showed a significant correlation with the hormones (p > 0.05).

CONCLUSION

There is a relationship with FSD and deficiency of vitamin D₃. Also, increased depressive symptoms were associated with FSD.

Maternal dietary vitamin D carry-over alters offspring growth, skeletal mineralisation and tissue mRNA expressions of genes related to vitamin D, calcium and phosphorus homoeostasis in swine

Maternal dietary vitamin D carry-over effects were assessed in young pigs to characterise skeletal abnormalities in a diet-induced model of kyphosis. Bone abnormalities were previously induced and bone mineral density (BMD) reduced in offspring from sows fed diets with inadequate vitamin D3. In a nested design, pigs from sows (n 23) fed diets with 0 (-D), 8·125 (+D) or 43·750 (++D) µg D3/kg from breeding through lactation were weaned and, within litter, fed nursery diets arranged as a 2×2 factorial design with 0 (-D) or 7·0 (+D) µg D3/kg, each with 95 % (95P) or 120 % (120P) of P requirements. Selected pigs were euthanised before colostrum consumption at birth (0 weeks, n 23), weaning (3 weeks, n 22) and after a growth period (8 weeks, n 185) for BMD, bone mechanical tests and tissue mRNA analysis. Pigs produced by +D or ++D sows had increased gain at 3 weeks (P<0·05), and at 8 weeks had increased BMD and improved femur mechanical properties. However, responses to nursery diets depended on maternal diets (P<0·05). Relative mRNA expressions of genes revealed a maternal dietary influence at birth in bone osteocalcin and at weaning in kidney 24-hydroxylase (P<0·05). Nursery treatments affected mRNA expressions at 8 weeks. Detection of a maternal and nursery diet interaction (P<0·05) provided insights into the long-term effects of maternal nutritional inputs. Characterising early stages of bone abnormalities provided inferences for humans and animals about maternal dietary influence on offspring skeletal health.

Vitamin D deficiency impairs skeletal muscle function in a smoking mouse model

Chronic obstructive pulmonary disease (COPD) is associated with skeletal muscle dysfunction. Vitamin D plays an important role in muscle strength and performance in healthy individuals. Vitamin D deficiency is highly prevalent in COPD, but its role in skeletal muscle dysfunction remains unclear. We examined the time-course effect of vitamin D deficiency on limb muscle function in mice with normal or deficient vitamin D serum levels exposed to air or cigarette smoke for 6, 12 or 18 weeks. The synergy of smoking and vitamin D deficiency increased lung inflammation and lung compliance from 6 weeks on with highest emphysema scores observed at 18 weeks. Smoking reduced body and muscle mass of the soleus and extensor digitorum longus (EDL), but did not affect contractility, despite type II atrophy. Vitamin D deficiency did not alter muscle mass but reduced muscle force over time, downregulated vitamin D receptor expression, and increased muscle lipid peroxidation but did not alter actin and myosin expression, fiber dimensions or twitch relaxation time. The combined effect of smoking and vitamin D deficiency did not further deteriorate muscle function but worsened soleus mass loss and EDL fiber atrophy at 18 weeks. We conclude that the synergy of smoking and vitamin D deficiency in contrast to its effect on lung disease, had different, independent but important noxious effects on skeletal muscles in a mouse model of mild COPD.

Maternal Vitamin D Deficiency Programs Reproductive Dysfunction in Female Mice Offspring Through Adverse Effects on the Neuroendocrine Axis

Vitamin D (VitD) deficiency affects more than 1 billion people worldwide with a higher prevalence in reproductive-aged women and children. The physiological effects of maternal VitD deficiency on the reproductive health of the offspring has not been studied. To determine whether maternal VitD deficiency affects reproductive physiology in female offspring, we monitored the reproductive physiology of C57BL/6J female offspring exposed to diet-induced maternal VitD deficiency at three specific developmental stages: 1) in utero, 2) preweaning, or 3) in utero and preweaning. We hypothesized that exposure to maternal VitD deficiency disrupts reproductive function in exposed female offspring. To test this hypothesis, we assessed vaginal opening and cytology and ovary and pituitary function as well as gonadotropin and gonadal steroid levels in female offspring. The in utero, preweaning, and in utero and preweaning VitD deficiency did not affect puberty. However, all female mice exposed to maternal VitD deficiency developed prolonged and irregular estrous cycles characterized by oligoovulation and extended periods of diestrus. Despite similar gonadal steroid levels and GnRH neuron density, females exposed to maternal VitD deficiency released less LH on the evening of proestrus. When compared with control female offspring, there was no significant difference in the ability of females exposed to maternal VitD deficiency to respond robustly to exogenous GnRH peptide or controlled ovarian hyperstimulation. These findings suggest that maternal VitD deficiency programs reproductive dysfunction in adult female offspring through adverse effects on hypothalamic function.

A novel rat model of vitamin D deficiency: safe and rapid induction of vitamin D and calcitriol deficiency without hyperparathyroidism

Vitamin D deficiency is associated with a range of clinical disorders. To study the mechanisms involved and improve treatments, animal models are tremendously useful. Current vitamin D deficient rat models have important practical limitations, including time requirements when using, exclusively, a vitamin D deficient diet. More importantly, induction of hypovitaminosis D causes significant fluctuations in parathyroid hormone (PTH) and mineral levels, complicating the interpretation of study results. To overcome these shortcomings, we report the successful induction of vitamin D deficiency within three weeks, with stable serum PTH and minerals levels, in Wistar rats. We incorporated two additional manoeuvres compared to a conventional diet. Firstly, the vitamin D depleted diet is calcium (Ca) enriched, to attenuate the development of secondary hyperparathyroidism. Secondly, six intraperitoneal injections of paricalcitol during the first two weeks are given to induce the rapid degradation of circulating vitamin D metabolites. After three weeks, serum 25-hydroxyvitamin D3 (25D) and 1,25-dihydroxyvitamin D3 (1,25D) levels had dropped below detection limits, with unchanged serum PTH, Ca, and phosphate (P) levels. Therefore, this model provides a useful tool to examine the sole effect of hypovitaminosis D, in a wide range of research settings, without confounding changes in PTH, Ca, and P.

Vitamin D improves endometrial thickness in PCOS women who need intrauterine insemination: a randomized double-blind placebo-controlled trial

PURPOSE

To determine whether administration of vitamin D affects the success rates of intra uterine insemination (IUI) in infertile polycystic ovarian syndrome (PCOS) women and their endometrial thickness.

METHODS

This randomized, double-blind, placebo-controlled trial was conducted in an infertility clinic of Women's Hospital, and 110 infertile PCOS patients undergoing IUI were randomly divided to receive vitamin D or placebo. Endometrial thickness, IUI results, number of dominant follicles, duration of IUI cycle, and dose of HMG used in IUI were determined.

RESULTS

The endometrial thickness was significantly different in the group treated with vitamin D versus the placebo group (p = 0.003). There was no statistical difference in pregnancy out come between the two groups (RR = 1.167, CI 95 % 0.70-1.93). No statistical difference was found in number of dominant follicles (p = 0.96), duration of IUI cycles (p = 0.70) and dose of HMG used for IUI (p = 0.95).

CONCLUSIONS

It seems that administration of vitamin D induces endometrial proliferation in PCOS women during IUI cycle. The study was recorded in Iranian Registry of Clinical Trials(IRCT201104216246N1).

Relevance of vitamin D in reproduction

The steroid hormone vitamin D is historically recognized for its relevance to bone health and calcium homeostasis. Recent years have witnessed a shift in focus to non-skeletal benefits of vitamin D; in this latter context, an accruing body of literature attests to a relevance of vitamin D to reproductive physiology. This article reviews the existing data about the diverse and previously underappreciated roles for vitamin D in reproductive health. A large body of available literature suggests that vitamin D deficiency may be detrimental to reproductive biology. However, given that our appreciation of vitamin D's role in reproductive physiology is almost entirely shaped by 'associative' studies and that data based on prospective interventional trials are limited, these concepts remain predominantly conjectural. Exact mechanisms whereby vitamin D may participate in the regulation of reproductive physiology remain far from clear. This review underscores a need for appropriately designed intervention trials to address the existing knowledge gaps and to delineate the specific roles of vitamin D signaling in reproductive biology.

Peripubertal vitamin D(3) deficiency delays puberty and disrupts the estrous cycle in adult female mice

The mechanism(s) by which vitamin D(3) regulates female reproduction is minimally understood. We tested the hypothesis that peripubertal vitamin D(3) deficiency disrupts hypothalamic-pituitary-ovarian physiology. To test this hypothesis, we used wild-type mice and Cyp27b1 (the rate-limiting enzyme in the synthesis of 1,25-dihydroxyvitamin D(3)) null mice to study the effect of vitamin D(3) deficiency on puberty and reproductive physiology. At the time of weaning, mice were randomized to a vitamin D(3)-replete or -deficient diet supplemented with calcium. We assessed the age of vaginal opening and first estrus (puberty markers), gonadotropin levels, ovarian histology, ovarian responsiveness to exogenous gonadotropins, and estrous cyclicity. Peripubertal vitamin D(3) deficiency significantly delayed vaginal opening without affecting the number of GnRH-immunopositive neurons or estradiol-negative feedback on gonadotropin levels during diestrus. Young adult females maintained on a vitamin D(3)-deficient diet after puberty had arrested follicular development and prolonged estrous cycles characterized by extended periods of diestrus. Ovaries of vitamin D(3)-deficient Cyp27b1 null mice responded to exogenous gonadotropins and deposited significantly more oocytes into the oviducts than mice maintained on a vitamin D(3)-replete diet. Estrous cycles were restored when vitamin D(3)-deficient Cyp27b1 null young adult females were transferred to a vitamin D(3)-replete diet. This study is the first to demonstrate that peripubertal vitamin D(3) sufficiency is important for an appropriately timed pubertal transition and maintenance of normal female reproductive physiology. These data suggest vitamin D(3) is a key regulator of neuroendocrine and ovarian physiology.

Calcium availability influences litter size and sex ratio in white-footed mice (Peromyscus leucopus)

The production of offspring typically requires investment of resources derived from both the environment and maternal somatic reserves. As such, the availability of either of these types of resources has the potential to limit the degree to which resources are allocated to reproduction. Theory and empirical studies have argued that mothers modify reproductive performance relative to exogenous resource availability and maternal condition by adjusting size, number or sex of offspring produced. These relationships have classically been defined relative to availability of energy sources; however, in vertebrates, calcium also plays a critical role in offspring production, as a considerable amount of calcium is required to support the development of offspring skeleton(s). We tested whether the availability of calcium influences reproductive output by providing female white-footed mice with a low-calcium or standard diet from reproductive maturity to senescence. We then compared maternal skeletal condition and reproductive output, based on offspring mass, offspring number and litter sex ratio, between dietary treatments. Mothers on the low-calcium diet exhibited diminished skeletal condition at senescence and produced smaller and strongly female-biased litters. We show that skeletal condition and calcium intake can influence sex ratio and reproductive output following general theoretical models of resource partitioning during reproduction.

Advanced glycation end-products as markers of aging and longevity in the long-lived Ansell's mole-rat (Fukomys anselli)

Mole-rat of the genus Fukomys are mammals whose life span is strongly influenced by reproductive status with breeders far outliving nonbreeders. This raises the important question of whether increased longevity of the breeders is reflected in atypical expression of biochemical markers of aging. Here, we measured markers of glycation and advanced glycation end-products formed in insoluble skin collagen of Ansell's mole-rat Fukomys anselli as a function of age and breeding status. Glucosepane, pentosidine, and total advanced glycation end-product content significantly increased with age after correction for breeder status and sex. Unexpectedly, total advanced glycation end-products, glucosepane, and carboxymethyl-lysine (CML) were significantly higher in breeders versus nonbreeders suggesting that breeders have evolved powerful defenses against combined oxidant and carbonyl stress compared with nonbreeders. Most interestingly, when compared with other mammals, pentosidine formation rate was lower in mole-rat compared with other short-lived rodents confirming previous observations of an inverse relationship between longevity and pentosidine formation rates in skin collagen.

Effects of 25OHD concentrations on chances of pregnancy and pregnancy outcomes: a cohort study in healthy Danish women

BACKGROUND/OBJECTIVES

Plasma 25-hydroxyvitamin D (P-25OHD) concentrations may affect pregnancy outcomes. To elucidate this further, we studied the effects of pre-conception P-25OHD concentrations on chances for pregnancy as well as the effects of P-25OHD during pregnancy on the risk of miscarriage, birth weight and length, Apgar score and head circumference. Moreover, we studied whether pregnancy and breastfeeding patterns affect maternal P-25OHD concentrations.

SUBJECTS/METHODS

A total of 153 healthy Caucasian women with pregnancy plans were followed with measurements performed before pregnancy, at pregnancy weeks 11±2, 22±1 and 35±2 as well as 15±7, 129±12 and 280±15 days postpartum. Furthermore, 75 non-pregnant, age-matched women were followed in parallel as controls.

RESULTS

The 203 women were aged 29 (25-35) years. At baseline, median P-25OHD was 59 nmol/l. Of these women, 31% had P-25OHD <50 nmol/l, whereas 12% had levels above 80 nmol/l. Within ∼6 months after inclusion, 63% conceived. P-25OHD was not associated with chances of conceiving or overall risk of miscarriage. However, women with a miscarriage in their second trimester (n=3) had lower P-25OHD concentrations at measurements performed in the first trimester compared with women without a miscarriage (P=0.03). P-25OHD before or during pregnancy was not associated with gestational length or infant parameters. Adjustments for possible confounders did not change the result. During pregnancy, P-25OHD changed significant over time, but similar changes occurred within the control group, indicating no effect of pregnancy per se (P=0.59). Overall, P-25OHD did not differ according to length of breastfeeding at 2 weeks, and 4 and 9 months postpartum, although women breastfeeding for >9 months had lower P-25OHD levels at the last visit compared with the controls.

CONCLUSION

P-25OHD concentrations did not affect fertility or pregnancy outcomes, although low P-25OHD may be associated with an increased risk of late miscarriage.

Effect of the vitamin D receptor on bone geometry and strength during gestation and lactation in mice

The vitamin D receptor (VDR) plays an important role in maintaining calcium homeostasis, acting as a mediator of transcellular calcium absorption and bone remodeling. Mice lacking a functional VDR have an abnormal skeletal phenotype, which is rescued by feeding a high-calcium diet. In this study, the role of the VDR in maintaining bone geometry and strength during gestation and lactation, when increased demands are placed on the calcium regulatory channels, was examined using a knockout mouse model. A rescue diet was used to counteract the decrease in calcium absorption in the gut that results from the absence of the VDR. Structural and compositional characteristics of the femur were compared between VDR knockout and wild-type mice following 9 and 16 days of gestation and 5 and 10 days of lactation using generalized linear models. Overall, the knockout mice had 6.5% lower cortical area, 23% lower trabecular volume fraction, and 9% lower bending stiffness than wild-type mice. However, the maximum moment of inertia of the femoral diaphyses, ultimate bending load, ash fraction, and trabecular thickness were not significantly different between knockout and wild-type mice. Only the mineral content exhibited interdependence between genotype and time point. Taken together, the results show that the VDR affects the quantity of mineralized bone tissue in the femoral diaphysis and metaphysis independently of reproductive status. However, the moments of inertia were similar between genotypes, resulting in similar bone stiffness and strength despite lower mineral content and cross-sectional area.

Replete vitamin D stores predict reproductive success following in vitro fertilization

OBJECTIVE

To determine whether 25OH-D levels in the follicular fluid (FF) of infertile women undergoing IVF demonstrate a relationship with IVF cycle parameters and outcome, hypothesizing that levels of 25OH-D in body fluids are reflective of vitamin repletion status.

DESIGN

Prospective cohort study.

SETTING

Academic tertiary care center.

PATIENT(S)

Eighty-four infertile women undergoing IVF.

INTERVENTION(S)

Follicular fluid from follicles>or=14 mm; serum (n = 10) and FF levels of 25OH-D.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy (CP), defined as evidence of intrauterine gestation sac on ultrasound, following IVF; IVF cycle parameters.

RESULT(S)

Serum and FF levels of 25OH-D were highly correlated (r=0.94). In a predominantly Caucasian population (66%), significantly lower FF 25OH-D levels were noted in Black versus non-Black patients. Significant inverse correlations were seen between FF 25OH-D levels and body mass index (r=-0.25). Significantly higher CP and implantation rates were observed across tertiles of FF25OH-D; patients achieving CP following IVF (n=26) exhibited significantly higher FF levels of 25OH-D. Multivariable logistic regression analysis confirmed FF 25OH-D levels as an independent predictor to success of an IVF cycle; adjusting for age, body mass index, ethnicity, and number of embryos transferred, each ng/mL increase in FF 25OH-D increased the likelihood for achieving CP by 6%.

CONCLUSION(S)

Our findings that women with higher vitamin D level in their serum and FF are significantly more likely to achieve CP following IVF-embryo transfer are novel. A potential for benefit of vitamin D supplementation on treatment success in infertile patients undergoing IVF is suggested and merits further investigation.

Evolution of our understanding of vitamin D

The development of our understanding of the function of vitamin D from its discovery in the second and third decades of the 20(th) century to its hormonal activation of its nuclear receptor and to its present position of an important factor in public health has been traced. The key discoveries of the conversion of vitamin D to its hormonal form, its regulation, and the evolving picture of its molecular mechanism of action are presented. The recognition of its role beyond mineralization of the skeleton to its role in skin, the immune system, and its protective role in some forms of malignancy represent more recent developments. The evolution of derivatives of 1alpha,25-dihydroxyvitamin D(3) as therapeutic agents suggests a richness of therapeutic potential. All of this nevertheless illustrates that much more remains to be discovered and applied to our armaments for preventing and treating disease.

Calcium metabolism of pregnant rats fed a vitamin D-depleted diet

The effects of vitamin D (VD) deficiency on calcium (Ca) metabolism during pregnancy were evaluated in rats fed VD-repleted (VD-repleted rats) and VD-depleted (VD-depleted rats) diets. In the VD-depleted rats, the plasma concentrations of 1,25-dihydroxyvitamin D and Ca decreased severely, whereas the parathyroid hormone concentrations increased. The Ca contents of the feces of the VD-depleted rats were higher than those of the VD-repleted rats. The fetal Ca contents of the VD-repleted and VD-depleted rats increased continuously, but that of the VD-depleted rats was lower. These data reveal that VD deficiency during pregnancy induces severe hypocalcemia due to reduced intestinal absorption of Ca and elevated fetal demand for Ca.

A prospective study of dairy foods intake and anovulatory infertility

BACKGROUND

Dairy foods and lactose may impair fertility by affecting ovulatory function. Yet, few studies have been conducted in humans and their results are inconsistent. We evaluated whether intake of dairy foods was associated with anovulatory infertility and whether this association differed according to fat content.

METHODS

We prospectively followed 18,555 married, premenopausal women without a history of infertility who attempted a pregnancy or became pregnant during an 8-year period. Diet was assessed twice during the study using food-frequency questionnaires.

RESULTS

During follow-up, 438 women reported infertility due to an ovulatory disorder. The multivariate-adjusted relative risks (RR) [95% confidence interval (CI); P, trend] of anovulatory infertility comparing women consuming > or = 2 servings per day to women consuming < or = 1 serving per week was 1.85 (1.24-2.77; 0.002) for low-fat dairy foods. The RR (95% CI; P, trend) comparing women consuming > or = 1 serving per day of high-fat dairy foods to those consuming < or = 1 serving per week was 0.73 (0.52-1.01; 0.01). There was an inverse association between dairy fat intake and anovulatory infertility (P, trend = 0.05). Intakes of lactose, calcium, phosphorus and vitamin D were unrelated to anovulatory infertility.

CONCLUSIONS

High intake of low-fat dairy foods may increase the risk of anovulatory infertility whereas intake of high-fat dairy foods may decrease this risk. Further, lactose (the main carbohydrate in milk and dairy products) may not affect fertility within the usual range of intake levels in humans.

Adapting to the transition between gestation and lactation: differences between rat, human and dairy cow

Adequate blood calcium concentrations are vital for the normal function of mammals. Mechanisms for maintaining normal blood calcium function adequately most of the time; however, occasionally they fail and calcium homeostasis is compromised. Milk fever or periparturient hypocalcemia in dairy cattle is a well-documented example of a breakdown in the mechanisms of calcium homeostasis. This disease occurs at the time of parturition and is unique to adult dairy animals. The disease results from the inability of animals to cope with the sudden demand for calcium in support of colostrum formation. Animals developing the disease become hypocalcemic and require intravenous calcium to survive. The precise metabolic disorder(s) responsible for the onset of milk fever is still being debated. This report will highlight some of the current concepts related to the causes and prevention of milk fever in dairy cattle, as well as contrasting differences in calcium demands that exist between dairy cattle, humans and rats at the onset of lactation.

Vitamin D receptor status alters mammary gland morphology and tumorigenesis in MMTV-neu mice

The vitamin D(3) receptor (VDR) is a ligand-dependent transcription factor implicated in regulation of cell cycle, differentiation and apoptosis of both normal and transformed cells derived from mammary gland. In these studies we examined whether VDR status altered mammary gland morphology or transformation in the well-characterized MMTV-neu transgenic model of breast cancer. We demonstrate that VDR protein is highly expressed in neu-positive epithelial cells of preneoplastic lesions, established tumors and lung metastases from MMTV-neu mice. Furthermore, MMTV-neu mice lacking VDR exhibit abnormal mammary ductal morphology characterized by dilated, distended ducts containing dysplastic epithelial cells. From 12 months of age on, MMTV-neu mice lacking VDR also experience body weight loss, atrophy of the mammary fat pad, estrogen deficiency and reduced survival. The limited survival of MMTV-neu mice lacking VDR precluded an accurate assessment of the impact of complete VDR ablation on tumor development. MMTV-neu mice heterozygous for VDR, however, did not exhibit body weight loss, mammary gland atrophy or compromised survival. Compared with MMTV-neu mice with two copies of the VDR gene, haploinsufficiency of VDR shortened the latency and increased the incidence of mammary tumor formation. Tumor histology and expression/subcellular localization of the neu transgene were not altered by VDR haploinsufficiency despite a significant decrease in tumor VDR expression. Collectively, these studies suggest that VDR gene dosage impacts on age-related changes in ductal morphology and oncogene-induced tumorigenesis of the mammary gland in vivo.