Vitamin D receptor and vitamin D metabolizing enzymes are expressed in the human male reproductive tract

Vitamin D alleviates chronic stress-induced testicular steroidogenesis disruption in Wistar rats

Stress is associated with various health issues. Research has highlighted the relationship between chronic stress and male reproductive health. One of the primary mechanisms underlying stress-induced male reproductive dysfunction is impaired steroidogenesis. In the present study, we validated a chronic unpredictable stress (CUS) model and investigated testicular dysfunction in CUS rats. The CUS paradigm involved exposing rats to a variety of stressors daily for 8 weeks. Vitamin D (10 µg/kg/twice a week, p.o) was administered to CUS rats starting 2 weeks after the onset of stress exposure and continued until the end of study. The stress in rats was confirmed by the occurrence of anxiety and depressive-like behaviours through elevated plus-maze test & novelty-suppressed feeding test and rise in serum corticosterone levels. Testicular dysfunction in CUS rats was assessed via serum gonadotropins, testosterone, cytokines, oxidative stress, and testis-epididymis-sperm morphology. The reduction in steroidogenesis was confirmed via immunohistochemical analysis of 17β-hydroxysteroid dehydrogenase-3 (17β-HSD3), steroidogenic acute regulatory gene (StAR) and vitamin D receptor (VDR) expression. Further, we studied the role of vitamin D in alleviating stress-induced testicular damage and the potential mechanisms underlying steroidogenic alterations in CUS rats. Notably, vitamin D treatment prevented CUS-induced decline in testicular 17β-HSD3, StAR and VDR expression. Moreover, vitamin D ameliorated the CUS-induced reduction in serum testosterone levels. Histological assessment revealed that vitamin D prevented CUS-induced damage in sperm, testis and epididymis morphology. In conclusion, our findings suggest that CUS exposure induces testicular dysfunction, which can be prevented by vitamin D, potentially through the regulation of steroidogenic pathways.

Value of inflammatory markers for monitoring disease severity and progression in granuloma induced by cosmetic oil injections

OBJECTIVE

Cosmetic oil injections can cause foreign body granulomas, leading to inflammation-driven extrarenal production of activated vitamin D (1,25(OH)2D3) and severe hypercalcemia. This study investigates longitudinal changes in inflammatory markers: interleukin 2 receptor (IL-2R), peptidyl dipeptidase (ACE), and ferritin in patients with oil-induced granuloma.

MATERIALS AND METHODS

109 male patients were stratified according to baseline calcium status. 28 % had hypercalcemia, and 72 % normocalcemia. Normocalcemic patients were subdivided based on serum parathyroid hormone (PTH) concentrations into suppressed (< 2.0 pmol/L, n = 30) or normal (≥ 2.0 pmol/L, n = 49) concentrations. Blood samples were collected over 48 months and longitudinal changes in inflammatory markers and calcium homeostasis were examined using Pearson correlation and mixed model analyses.

RESULTS

IL-2R, ACE, and ferritin were positively correlated with serum concentration of ionized calcium, while IL-2R was associated with serum 1,25(OH)2D3. In patients with hypercalcemia, IL-2R decreased at 6 (p = 0.041), 24 (p = 0.048), and 36 months (p = 0.035). ACE increased at 48 months (p = 0.008). In patients with normocalcemia and suppressed PTH, IL-2R increased at 24 months (p = 0.021), while serum ferritin increased in patients with normocalcemia and normal PTH at 6 (p = 0.040), 12 (p = 0.008), 24 (p = 0.028), and 48 months (p = 0.005).

CONCLUSIONS

Positive correlations were observed at baseline between ionized calcium concentrations and IL-2R, ionized calcium and ferritin, and 1,25(OH)₂D₃ and IL-2R. Hypercalcemia and suppressed PTH was associated with elevated IL-2R and ferritin concentrations at baseline. Over time, IL-2R and ferritin concentrations decreased in patients with hypercalcemia, some treated with immunomodulatory drugs. IL-2R and ferritin concentrations increased in untreated patients with normocalcemia.

1,25(OH)2D3 up-regulated mitochondrial dynamics and biogenesis to modulate steroidogenesis in the scent glands of muskrats (Ondatra zibethicus)

Vitamin D3 plays a crucial regulatory role in steroid hormone production, but the specific mechanism remains not fully understood. In this study, we investigated the expression and distribution patterns of Vitamin D receptor (VDR), vitamin D3 metabolic enzymes (CYP2R1, CYP27B1 and CYP24A1), mitochondrial dynamics and biogenesis (proteins and genes), and steroidogenic enzymes in the scent glands of muskrats during the breeding and non-breeding periods. VDR, vitamin D3 metabolic enzymes, mitochondrial dynamics and biogenesis-related proteins, and steroidogenic enzymes were immunolocalized in the scent glandular cells in both breeding and non-breeding seasons, with stronger immunostaining in the breeding season. The mRNA expression levels of Cyp27b1, Cyp24a1, Vdr, Mfn1, Opa1, Vdac, Tfam, Pgc1b, Star, Cyp11a1, Cyp17a1, and Cyp19a1 were higher in the scent glands during the breeding season than those of the non-breeding season. 1,25(OH)₂D₃ concentration were positively correlated with the mean mRNA expression levels of mitochondrial dynamics and biogenesis marker genes and steroidogenic enzymes in the scent glands. The concentrations of circulating testosterone (T) and 17β-estradiol (E2), and 1,25(OH)₂D₃ of the scent glands were also significantly higher in the breeding season. Additionally, the addition of 1,25(OH)2D3 to the primary scent glandular cells in vitro increased the expression levels of mitochondrial dynamics and biogenesis-related genes and steroidogenic enzymes in the scent glands of muskrats. These findings suggested that 1,25(OH)₂D₃ might promote the secretion of steroid hormones by upregulating the mitochondrial dynamics and biogenesis in the scent glands of muskrats.

Importance of assessing erectile dysfunction in patients with type 2 diabetes mellitus based on glucose fluctuation: a Cross-Sectional study

PURPOSE

To investigate the relationship between glucose fluctuation and erectile dysfunction (ED) in patients with type 2 diabetes mellitus (T2DM).

METHODS

This cross-sectional study included 317 male patients with T2DM. Participants were categorized into non-ED group (76 cases) and ED group (241 cases) based on International Index of Erectile Function-5 (IIEF-5) scores. Patients were additionally segmented into quartiles based on time in range (TIR). Demographic and laboratory data were collected, and glucose fluctuation indicators were ascertained using flash glucose monitoring.

RESULTS

The ED group exhibited significantly lower TIR and IIEF-5 scores compared to the non-ED group (P < 0.05). An increase in TIR levels corresponded with higher IIEF-5 scores and a significant reduction in ED incidence (P < 0.05). Spearman's correlation analysis indicated a positive correlation between IIEF-5 scores and TIR (r = 0.48, P < 0.01). Restricted cubic spline analysis revealed a negative linear association between TIR and ED (P for linearity <0.05). Multivariate logistic regression analysis, after adjusting for confounding factors, confirmed that low TIR is an independent risk factor for ED (P < 0.05).

CONCLUSION

Glucose fluctuation in T2DM patients correlate with ED, with low TIR being independently and positively associated with ED incidence, suggesting it may be a significant risk factor for ED in patients with T2DM.

Associations between serum and seminal vitamin D levels and sperm parameters

AIM

To examine the association between serum/seminal plasma vitamin D levels and sperm parameters, the possible effects of serum/seminal vitamin D on sperm motility via seminal intracellular calcium measurement, and the antioxidant effect via malondialdehyde (MDA) measurement.

METHODS

This prospective study was conducted on 87 male patients. Serum vitamin D levels of patients were evaluated and grouped based on their serum vitamin D levels: low (<50 nmol/L), normal (50-75 nmol/L), and high (>75 nmol/L). Sperm characteristics were evaluated. Seminal plasma vitamin D, intracellular calcium, and MDA concentrations were measured using Liquid Chromatography Mass Spectrometry (LC-MS/MS), High-performance liquid chromatography (HPLC), and fluorescence plate reader methods, respectively.

RESULTS

Patients with normal serum vitamin D levels had higher total progressive motile sperm concentrations (14.0 vs. 8.5 vs. 4 million/mL, p = 0.037) and higher normal sperm morphology (6% vs. 4% vs. 3%, p = 0.020) compared to those with low and high levels. No correlations were found between serum vitamin D levels and seminal vitamin D (r = 0.052, p = 0.468), MDA (r = -0.048, p = 0.791), and intracellular calcium levels (r = 0.064, p = 0.929). Seminal intracellular calcium levels were significantly correlated with total (r = 0.241, p = 0.024) and progressive (r = 0.217, p = 0.043) sperm motility.

CONCLUSIONS

There were positive correlations between serum vitamin D levels, total progressive motile sperm concentration, and normal sperm morphology. However, serum vitamin D levels were not correlated with seminal vitamin D levels and showed no correlations with potential mechanisms of action, reflected by intracellular calcium and MDA concentrations. Conversely, intracellular calcium levels were positively correlated with both total and progressive sperm motility, suggesting that intracellular calcium plays an essential role in sperm motility.

Gender-specific association between circulating 25-hydroxyvitamin D levels and diabetic retinopathy in patients with type 2 diabetes mellitus

Background

Diabetic retinopathy (DR), one of the most common microvascular complications of diabetes mellitus (DM), remains to be a major driver of vision loss worldwide. Vitamin D has been reported to be involved in DR pathogenesis, but results have been inconsistent. We aimed to explore the relationship between blood 25-hydroxyvitamin D, 25(OH)D, level and the risk of DR in patients with type 2 diabetes (T2DM).

Methods

A total of 535 adults with T2DM from our department were included. Demographic information, biochemical data, 25(OH)D, and sex hormones were collected. Fundus photography was performed to determine the presence of DR. Participants were grouped into the DR group and the non-DR (NDR) group according to the fundus examinations and four groups based on serum 25(OH)D levels as follows: normal, insufficient, deficient, and severely deficient. Multivariate logistic regression analysis was used to evaluate the association between 25(OH)D and risk of DR.

Results

Males but not females with DR had significantly decreased levels of 25(OH)D (16.4 ± 5.6 ng/ml vs. 21.0 ± 5.0 ng/ml, P = 0.001) and increased proportion of severe 25(OH)D deficiency (14.8% vs. 6.7%, P = 0.022) compared to those without DR. Likewise, there was a gradually increasing percentage of DR with the reduction of 25(OH)D levels only in males (35.7%, 44.4%, 53.2%, 70.3%, P = 0.022). Intriguingly, total testosterone (TT) levels decreased markedly in males with DR (12.9 ± 5.2 nmol/L vs. 14.2 ± 5.5 nmol/L, P = 0.035) compared to their counterparts and correlated positively with 25(OH)D (β = 0.161, P = 0.007), which did not occur in females. After multivariate adjustment, we observed a significant inverse association between serum 25(OH)D and the occurrence of DR in males, showing that the adjusted ORs (AORs) and 95% confidence interval for DR were 0.233 (0.070-0.779) in the normal group, 0.280 (0.103-0.756) in the insufficient group, and 0.477 (0.196-1.164) in the deficiency group with the severely deficient group as a reference (P-trend = 0.003). However, such a significant association was not observed in females (P-trend = 0.137).

Conclusion

We concluded a gender-specific relationship between serum 25(OH)D and the incidence of DR in T2DM, supported by a significant inverse association between serum 25(OH)D and DR only in males, which could be mediated by a marked reduction in TT levels.

Changes in local mineral homeostasis facilitate the formation of benign and malignant testicular microcalcifications

Testicular microcalcifications consist of hydroxyapatite and have been associated with an increased risk of testicular germ cell tumors (TGCTs) but are also found in benign cases such as loss-of-function variants in the phosphate transporter SLC34A2. Here, we show that fibroblast growth factor 23 (FGF23), a regulator of phosphate homeostasis, is expressed in testicular germ cell neoplasia in situ (GCNIS), embryonal carcinoma (EC), and human embryonic stem cells. FGF23 is not glycosylated in TGCTs and therefore cleaved into a C-terminal fragment which competitively antagonizes full-length FGF23. Here, Fgf23 knockout mice presented with marked calcifications in the epididymis, spermatogenic arrest, and focally germ cells expressing the osteoblast marker Osteocalcin (gene name: Bglap, protein name). Moreover, the frequent testicular microcalcifications in mice with no functional androgen receptor and lack of circulating gonadotropins are associated with lower Slc34a2 and higher Bglap/Slc34a1 (protein name: NPT2a) expression compared with wild-type mice. In accordance, human testicular specimens with microcalcifications also have lower SLC34A2 and a subpopulation of germ cells express phosphate transporter NPT2a, Osteocalcin, and RUNX2 highlighting aberrant local phosphate handling and expression of bone-specific proteins. Mineral disturbance in vitro using calcium or phosphate treatment induced deposition of calcium phosphate in a spermatogonial cell line and this effect was fully rescued by the mineralization inhibitor pyrophosphate. In conclusion, testicular microcalcifications arise secondary to local alterations in mineral homeostasis, which in combination with impaired Sertoli cell function and reduced levels of mineralization inhibitors due to high alkaline phosphatase activity in GCNIS and TGCTs facilitate osteogenic-like differentiation of testicular cells and deposition of hydroxyapatite.

Joint and individual associations between multiple vitamins and sperm quality in adult men

Background

Several studies have suggested that a healthy diet is associated with improved male fertility outcomes. However, the joint and individual associations between the status of multiple vitamins and sperm quality remain unclear.

Objectives

This study aimed to investigate the associations between serum vitamin levels and sperm quality parameters in adult men.

Methods

A cross-sectional study was conducted among 156 adult men seeking fertility care at a reproductive center from December 2023 to June 2024. Blood and semen were collected on the same day to determine the concentrations of nine kinds of vitamins (B1, B2, B6, B9, B12, C, A, D, E) and five parameters of sperm quality [total sperm number, sperm concentration, progressive motile sperm, morphologically normal rate, and DNA fragment index (DFI)]. The joint and individual associations between vitamin levels and sperm quality were analyzed using multiple linear regression and Bayesian kernel machine regression (BKMR) models.

Results

Increased tertiles of vitamin B1 and 1,25-dihydroxyvitamin D3 [1,25-(OH)2-D3] in serum were associated with higher sperm quality (all P for trends < 0.10). Compared with the lowest tertiles, the highest tertiles of vitamin B12 had β: 3.0 (95% CI: 0.8, 5.2) increasing in DFI, and vitamin A was negatively associated with progressive sperm motility (P for trends = 0.05). We generally found null results between multiple vitamin levels and the parameters of sperm quality in the BKMR models.

Discussion

These research findings imply that vitamins could have a dose-dependent dual effect on sperm quality. More specifically, the impact of vitamins varies according to their dosage levels and types. Personalized vitamin supplementation may be more effective than taking multivitamins in improving sperm quality.

Vitamin D in Reproductive Health Disorders: A Narrative Review Focusing on Infertility, Endometriosis, and Polycystic Ovarian Syndrome

Vitamin D (VD) is a fat-soluble steroid hormone with essential physiological functions beyond calcium and bone metabolism. In recent years, its role in women's reproductive health has gained attention, influencing ovarian function, follicular development, endometrial receptivity, and steroid hormone regulation. VD deficiency has been linked to reproductive disorders such as polycystic ovarian syndrome (PCOS), endometriosis, and infertility. Studies indicate that up to 40-50% of healthy pregnant women have insufficient VD levels, which may contribute to adverse pregnancy outcomes and reduced fertility. With growing evidence connecting VD to reproductive health, this review examines its molecular and endocrine mechanisms in fertility, endometriosis, and PCOS. It explores VD's therapeutic potential and its implications for improving clinical approaches and future research in reproductive medicine. Maintaining adequate VD levels is crucial for ovarian function, immune modulation in reproductive tissues, and overall fertility. Its deficiency is associated with insulin resistance, hormonal imbalances, and inflammatory processes, which contribute to reproductive pathophysiology. Establishing reference values for VD in reproductive medicine is essential for optimizing fertility treatments and improving clinical outcomes. This review synthesizes current research on VD's role in reproductive health and highlights the need for further investigation into its therapeutic applications.

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.

All Properties of Infertility Microbiome in a Review Article

BACKGROUND

The microbiome is crucial for many physiological processes, including immunity, metabolism, and reproduction.

AIMS

This review aims to contribute to a detailed understanding of the microbiome of the genital tract, which can lead to better management of dysbiosis and reproductive disorders.

METHODS

Data from the four international information databases Medline, Scopus, Embase, and Google Scholar. The search strategy was based on the combination of the following terms: "microbiota," "microbiome," "microfilm," "microflora," "fertility," or "infertility."

RESULT

The advent of next-generation sequencing-based technologies during the last decade has revealed the presence of microbial communities in nearly every part of the human body, including the reproductive system. Several studies have shown significant differences between the microbiota of the vagina and endometrium, as well as other parts of the upper genital tract.

DISCUSSION

The human microbiome plays a critical role in determining a person's health state, and the microbiome of the genital tract may impact fertility potential before and after assisted reproductive treatments (ARTs).

CONCLUSION

To completely understand the role of the microbiome, future research should focus not only on the description of microbiota but also on the interaction between bacteria, the production of biofilms, and the interaction of microorganisms with human cells.

Vitamin D in pituitary driven osteopathies

The evidence that pituitary hormones may bypass peripheral endocrine glands to exert remarkable effects on the skeleton is gaining ground. Both hormonal excess and deficit may determine impairment in bone structure, and they commonly result in bone loss in patients affected by pituitary and neuroendocrine disorders. Vertebral fractures are the most common skeletal alterations and may occur independently of bone mass. Use of vitamin D (VD) supplementation is still debated in this setting. This review will focus on the interactions between different metabolites of VD and pituitary hormones, and the effects of VD supplementation on bone metabolism in patients with pituitary diseases.

Epigenetic aging of semen is associated with inflammation

Male infertility has been a primary cause of global infertility, affecting 8-12% of couples worldwide. Previous studies have shown that semen quality decreases with advanced aging with an increased presence of inflammatory cells. In this study, we examined changes in the epigenome across a diverse cohort that includes both fertile and infertile men. We also compare the age-associated changes in semen to those observed in buccal swabs in order to characterize differences in epigenetic aging across diverse tissues. We found that variations in the semen methylome associated with aging are linked to inflammatory genes. Many age-associated sites are demethylated with advanced aging and are associated with the activation of inflammatory pathways. By contrast, we do not observe age-associated changes in inflammatory genes in buccal swab methylomes, which instead are characterized by changes to bivalent promoters. Our findings highlight the potential of epigenetic markers as indicators of male reproductive health.

Modulation of NRF2 and CYP24A1 Pathways by Hookah Smoke: Implications for Male Reproductive Health

Antioxidants act by preventing excessive oxidative stress within the developing sperm cells. Hookah smoking has been implicated in inducing oxidative stress which may be a risk factor for male infertility. This study aims to bridge this knowledge gap by evaluating the effect of hookah smoking on sperm quality and the expression of nuclear factor erythroid 2-related factor 2 (NRF2) and Cytochrome P450 family 24 subfamily A member 1 (CYP24A1) genes which are involved in antioxidant response. Young fertile men in reproductive age were categorized into hookah smokers (n = 32) and non-smokers (n=52). Sperm parameters (concentration, volume, motility, morphology) as well as gene expression of NRF2 and CYP24A1 were evaluated in each sperm sample. There was no meaningful change in sperm parameters in the case group compared with the controls. The mRNA levels of NRF2 was significantly higher in the case group compared with the controls (p = 0.01), while CYP24A1 expression did not significantly change between the study groups. A remarkable increase in NRF2 expression in hookah smokers might be a cellular defense mechanism, indicating activation of antioxidant response in sperm to counteract potential oxidative stress caused by hookah use. However, further research is needed to understand the functional consequences of this upregulation.

The Impact of Vitamin D on Androgens and Anabolic Steroids among Adult Males: A Meta-Analytic Review

BACKGROUND

Recent studies indicate that vitamin D impacts male reproductive function, with deficiency linked to infertility. This review evaluates the effect of vitamin D supplementation on male fertility, focusing on total testosterone, free testosterone, the free androgen index (FAI), follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex-hormone-binding globulin (SHBG), and estradiol.

METHODS

We systematically searched Medline, Web of Science, Cochrane Library, and Scopus from their inception until July 2024 for randomized controlled trials (RCTs) involving adult males. The primary focus of these studies was on reproductive hormone parameters, analyzed using a random-effects meta-analysis and weighted mean difference (WMD). Evidence quality was assessed using ROB2 and GRADE. Meta-regression and dose-response analyses were performed.

RESULTS

Seventeen studies met the criteria for quantitative analysis. Vitamin D supplementation significantly increased total testosterone levels (WMD 0.38, 95% CI 0.06-0.70, n = 15, I2 = 67.03). However, it had no significant effect on other hormone parameters: free testosterone (WMD 0.00, 95% CI -0.02-0.03, n = 9, I2 = 48.12), FSH (WMD -0.02, 95% CI -0.57-0.53, n = 7, I2 = 48.72), LH (WMD -0.09, 95% CI -0.30-0.12, n = 8, I2 = 0.00), SHBG (WMD 0.73, 95% CI -1.14-2.61, n = 10, I2 = 69.05), FAI (WMD -0.92, 95% CI -2.12-0.27, n = 6, I2 = 0.00), and estradiol (WMD -0.02, 95% CI -2.95-2.92, n = 5, I2 = 20.63).

CONCLUSION

This meta-analysis shows that vitamin D supplementation may increase total testosterone levels in men. However, further well-designed RCTs are needed to determine vitamin D's effects on other reproductive hormone parameters.

Relationship between serum vitamin D concentration and parameters of gonadal function in infertile male patients

Background

Vitamin D (vitD) deficiency could affect male reproductive function. Our objective was to investigate the relationship between serum vitD concentrations and hormonal and seminal parameters in infertile patients and to compare the results with those in healthy controls.

Materials and methods

Infertile patients (n = 29) and normozoospermic healthy donors (n = 27) were recruited for the study. Serum concentrations of vitD, total testosterone, estradiol, and sex hormone-binding globulin were determined using chemiluminescence assays, and free testosterone concentration was determined by radioimmunoassay. Semen analysis was performed as suggested by the World Health Organization. Statistical analysis was conducted using Student's t test, contingency tables, and linear regression studies.

Results

VitD concentrations were lower in patients than in controls (p < 0.001). A significant association (p < 0.001) was observed between vitD concentrations <20ng/mL and infertility. In the control group, significant correlations were reported between vitD concentrations >30 ng/mL and the concentrations of testosterone (p < 0.05), free testosterone (p < 0.01), and estradiol (p < 0.05). A direct correlation was found between vitD concentration and percentage of sperm vitality (p = 0.01). VitD also positively correlated with the percentage of progressive sperm motility (p <0.05) and sex hormone-binding globulin concentrations (p < 0.01).

Conclusions

VitD may affect male reproductive parameters, and its deficiency could be associated with infertility.

An association weight matrix identified biological pathways associated with bull fertility traits in a multi-breed population

Using seven indicator traits, we investigated the genetic basis of bull fertility and predicted gene interactions from SNP associations. We used percent normal sperm as the key phenotype for the association weight matrix-partial correlation information theory (AWM-PCIT) approach. Beyond a simple list of candidate genes, AWM-PCIT predicts significant gene interactions and associations for the selected traits. These interactions formed a network of 537 genes: 38 genes were transcription cofactors, and 41 genes were transcription factors. The network displayed two distinct clusters, one with 294 genes and another with 243 genes. The network is enriched in fertility-associated pathways: steroid biosynthesis, p53 signalling, and the pentose phosphate pathway. Enrichment analysis also highlighted gene ontology terms associated with 'regulation of neurotransmitter secretion' and 'chromatin formation'. Our network recapitulates some genes previously implicated in another network built with lower-density genotypes. Sequence-level data also highlights additional candidate genes relevant to bull fertility, such as FOXO4, FOXP3, GATA1, CYP27B1, and EBP. A trio of regulatory genes-KDM5C, LRRK2, and PME-was deemed core to the network because of their overarching connections. This trio probably influences bull fertility through their interaction with genes, both known and unknown as to their role in male fertility. Future studies may target the trio and their target genes to enrich our understanding of male fertility further.

The effects of supplementation of vitamin D to the egg-yolk extender on cryopreservation of ram semen

OBJECTIVES

This study aimed to examine the effects of supplementation of vitamin D to the egg-yolk extender on characteristics of frozen-thawed ram semen.

METHODS

Semen samples obtained from adult rams were pooled and divided into five equal volumes. It was reconstituted with extenders containing different concentrations of vitamin D: 0 (control), 12.5 (VITD 12.5), 25 (VITD 25), 50 (VITD 50), and 100 ng/mL (VITD 100), and then they were frozen. Sperm motility parameters, plasma membrane functional integrity, acrosomal integrity, DNA fragmentation, and mitochondrial membrane potential of the groups were evaluated after sperm thawing.

RESULTS

Total motility and progressive motility were higher in VITD 50 than in all other groups (p < 0.05). Higher sperm straightness, linearity, and wooble were higher in VITD 50 than in the control group (p < 0.05). A similar pattern of VITD 50 was observed for plasma membrane integrity and mitochondrial membrane potential (p > 0.05).

CONCLUSIONS

In the study, it was observed that adding vitamin D to the extender had a beneficial effect on ram spermatological parameters. In addition, it was concluded that the use of the 50 ng/mL vitamin D in the extender provided more effective protection than the other doses.

Effects of Simulated Microgravity on Rat Reproductive System: Potential Benefits of Vitamin D3 Intervention

Gravity in space can have a negative impact on the reproductive system. Given that the reproductive system is one of vitamin D's objectives, this study will use a simulated microgravity model to evaluate its impact on the rat reproductive system.Twenty-two male Wistar rats were allocated into four groups at random. Under microgravity circumstances, the rats were housed in both special and standard cages. Each group was then separated into two subgroups, one of which received vitamin D3 and the other did not. Blood was drawn twice to determine blood levels of vitamin D3, LH, FSH, and testosterone. Rat testes were isolated for histological analysis, as well as a piece of epididymis for sperm count and morphological examination.Microgravity had a detrimental effect on testicular tissue, resulting in lower serum levels of LH and testosterone (p-value < 0.001). Spermatogenesis was largely inhibited under microgravity. During microgravity conditions, however, vitamin D3 had a good effect on testicular structure, and the total number of sperm. Simulated microgravity affects the male reproductive system, compromising testicular morphology, sperm parameters, and hormonal balance. However, this study shows that vitamin D3 supplementation can act as a preventative strategy, minimizing the negative consequences of microgravity. The beneficial effect of vitamin D3 on testicular health and sperm quality implies that it may be useful in protecting male reproductive function in space-related situations.

The Impact of Vitamin D and L-Cysteine Co-Supplementation on Upregulating Glutathione and Vitamin D-Metabolizing Genes and in the Treatment of Circulating 25-Hydroxy Vitamin D Deficiency

Vitamin D receptors are expressed in many organs and tissues, which suggests that vitamin D (VD) affects physiological functions beyond its role in maintaining bone health. Deficiency or inadequacy of 25(OH)VD is widespread globally. Population studies demonstrate that a positive association exists between a high incidence of VD deficiency and a high incidence of chronic diseases, including dementia, diabetes, and heart disease. However, many subjects have difficulty achieving the required circulating levels of 25(OH)VD even after high-dose VD supplementation, and randomized controlled clinical trials have reported limited therapeutic success post-VD supplementation. Thus, there is a discordance between the benefits of VD supplementation and the prevention of chronic diseases in those with VD deficiency. Why this dissociation exists is currently under debate and is of significant public interest. This review discusses the downregulation of VD-metabolizing genes needed to convert consumed VD into 25(OH)VD to enable its metabolic action exhibited by subjects with metabolic syndrome, obesity, and other chronic diseases. Research findings indicate a positive correlation between the levels of 25(OH)VD and glutathione (GSH) in both healthy and diabetic individuals. Cell culture and animal experiments reveal a novel mechanism through which the status of GSH can positively impact the expression of VD metabolism genes. This review highlights that for better success, VD deficiency needs to be corrected at multiple levels: (i) VD supplements and/or VD-rich foods need to be consumed to provide adequate VD, and (ii) the body needs to be able to upregulate VD-metabolizing genes to convert VD into 25(OH)VD and then to 1,25(OH)2VD to enhance its metabolic action. This review outlines the association between 25(OH)VD deficiency/inadequacy and decreased GSH levels, highlighting the positive impact of combined VD+LC supplementation on upregulating GSH, VD-metabolizing genes, and VDR. These effects have the potential to enhance 25(OH)VD levels and its therapeutic efficacy.

Vitamin D and reproductive disorders: a comprehensive review with a focus on endometriosis

Vitamin D is a fat-soluble steroid hormone that was initially known only for regulating calcium and phosphorus levels and maintaining bone health. However, it was later discovered that many organs express vitamin D metabolizing enzymes and have a ligand for vitamin D, which regulates the expression of an extensive assortment of genes. As a result, vitamin D is indispensable for the proper function of organs, and its deficiency is believed to be a critical factor in symptoms and disorders such as cardiovascular diseases, autoimmune diseases, and cancers. The significance of vitamin D in reproductive tissues was recognized later, and studies have revealed its crucial role in male and female fertility, as well as proper reproductive function during pregnancy. Vitamin D deficiency has been identified as a risk factor for infertility, gonadal cancers, pregnancy complications, polycystic ovary syndrome, and endometriosis. However, data investigating the association between vitamin D levels and reproductive disorders, including endometriosis, have encountered inconsistencies. Therefore, the present study aims to review existing research on the effect of vitamin D on proper reproductive function, and the role of deficiency in reproductive diseases and specifically focuses on endometriosis.

Do serum vitamin D levels affect assisted reproductive outcomes and perinatal outcomes in young non-PCOS patients? A retrospective study

PURPOSE

This study aimed to determine the influence of serum vitamin D levels on assisted reproductive and perinatal outcomes in young non-polycystic ovary syndrome (PCOS) patients.

METHODS

A total of 3397 non-PCOS women under 35 years who underwent their first IVF/ICSI cycle at the Reproductive Medicine Center of the Third Affiliated Hospital of Zhengzhou University, from 2018 to 2019, were included. The women were categorized into two groups based on their serum 25(OH)D concentrations: deficient group [25(OH)D < 50 nmol/L] and non-deficient group [25(OH)D ≥ 50 nmol/L]. Ovulation induction results, clinical pregnancy rate, cumulative live birth rate (CLBR), and perinatal outcomes of both groups were compared.

RESULTS

A total of 1113 non-PCOS women had successful pregnancies in their first completed IVF cycle. Comparison of laboratory results between the two groups revealed a significantly higher number of oocytes retrieved in the vitamin D-non-deficient group (15.2 ± 6.8 vs. 14.5 ± 6.7, p = 0.015). After controlling for confounding factors, there was no significant difference in the CLBR between the vitamin D-deficient group and the non-deficient group (71.0%, 1,973/2,778 vs. 69.0%, 427/619, p = 0.314, unadjusted). The prevalence of gestational diabetes mellitus (GDM) was higher in the vitamin D-deficient group than in the vitamin D-non-deficient group in both fresh-cycle singleton live births (3.8% vs. 1.2%) and twin live births (2.3% vs. 1.5%).

CONCLUSION

This study demonstrated that vitamin D-deficient group had a lower number of oocytes retrieved than the non-deficient group and a higher prevalence of GDM, suggesting that vitamin D deficiency impacts assisted pregnancies and perinatal outcomes in infertile non-PCOS women. However, further studies are required to confirm these findings.

Calcium and vitamin D homoeostasis in male fertility

Calcium and vitamin D have well-established roles in maintaining calcium balance and bone health. Decades of research in human subjects and animals have revealed that calcium and vitamin D also have effects on many other organs including male reproductive organs. The presence of calcium-sensing receptor, vitamin D receptor, vitamin D activating and inactivating enzymes and calcium channels in the testes, male reproductive tract and human spermatozoa suggests that vitamin D and calcium may modify male reproductive function. Functional animal models have shown that vitamin D deficiency in male rodents leads to a decrease in successful mating and fewer pregnancies, often caused by impaired sperm motility and poor sperm morphology. Human studies have to a lesser extent validated these findings; however, newer studies suggest a positive effect of vitamin D supplementation on semen quality in cases with vitamin D deficiency, which highlights the need for initiatives to prevent vitamin D deficiency. Calcium channels in male reproductive organs and spermatozoa contribute to the regulation of sperm motility and capacitation, both essential for successful fertilisation, which supports a need to avoid calcium deficiency. Studies have demonstrated that vitamin D, as a regulator of calcium homoeostasis, influences calcium influx in the testis and spermatozoa. Emerging evidence suggests a potential link between vitamin D deficiency and male infertility, although further investigation is needed to establish a definitive causal relationship. Understanding the interplay between vitamin D, calcium and male reproductive health may open new avenues for improving fertility outcomes in men.

Effects of vitamin D on sex steroids, luteinizing hormone, and testosterone to luteinizing hormone ratio in 307 infertile men

OBJECTIVE

Vitamin D status has been associated with sex steroid production. The question is whether vitamin D supplementation has an impact on sex steroid production in infertile men with vitamin D insufficiency?

DESIGN

A single-center, double-blinded, randomized clinical trial. Differences in sex steroids and reproductive hormones were predefined secondary outcomes, vitamin D status at baseline was a predefined subgroup and the primary outcome was differences in semen quality.

METHODS

A total of 307 infertile men were included and randomized 1:1 to active or placebo treatment for 150 days. Men in the active group initially received an oral bolus of 300,000 IU cholecalciferol, followed by daily supplementation with 1400 IU cholecalciferol and 500 mg calcium.

RESULTS

After intervention, no differences were found in serum concentrations of sex steroids, luteinizing hormone, testosterone/luteinizing hormone ratio or SHBG between the vitamin D and placebo group. However, in a predefined subgroup analysis of men with serum 25OHD ≤ 50 nmol/L, men treated with vitamin D had a significantly higher testosterone/luteinizing hormone ratio [4.2 (3.8-4.4) vs. 3.7 (3.4-4.0); p = 0.033] compared with placebo treatment. In men with vitamin D deficiency, the difference between groups was larger but not significant due to few men with serum 25OHD < 25 nmol/L.

CONCLUSION

Vitamin D + calcium supplementation did not alter sex steroid production in infertile men. However, vitamin D insufficient men treated with vitamin D supplementation had a significantly higher testosterone/LH ratio compared with placebo-treated men, suggesting that optimal Leydig cell function are dependent on adequate vitamin D status.

Vitamin D Abuse in Pursuit of "Gains" Resulting in Acute Kidney Injury

Vitamin toxicity represents an increasingly frequent clinical diagnosis and can be difficult to initially recognize given the plethora of over-the-counter supplements available. The young, active, and heavily male population of the military is especially susceptible to such supplementation pitfalls. Here we present the case of acute renal failure with hypercalcemia that was found to be secondary to unrecognized high-dose over-the-counter vitamin supplementation and subsequent vitamin D hypervitaminosis initiated by the patient in the hope of boosting testosterone production. This clinical scenario demonstrates the dangers of easily accessible, often seemingly benign supplements and the need for greater education and awareness of supplementation use.

High-dose vitamin D3 supplementation shows no beneficial effects on white blood cell counts, acute phase reactants, or frequency of respiratory infections

BACKGROUND

Vitamin D has been suggested to influence the immune system, and vitamin D metabolites and the vitamin D receptor (VDR) are generated and expressed in white blood cells (WBC). Moreover, vitamin D status has been associated with incidence and prognosis of some respiratory tract infections (RTI). Therefore, we investigated the effect of vitamin D3 supplementation on WBC, acute phase reactants (APR), and the risk of developing RTIs.

METHODS

A double-blinded, randomized, placebo-controlled clinical trial of 307 infertile men with multiple secondary immunological endpoints. The vitamin D3 group (n = 151) initially received 300,000 IU (7,500 µg) cholecalciferol once - followed by 1,400 IU (35 µg) daily for 150 days. The placebo group (n = 156) did not receive active ingredients.

RESULTS

At baseline, stratification into clinically relevant groups of vitamin D status (< 25; 25-50; 50-75; >75 nmol/L), showed an inverse association with total leucocyte concentrations (7.0 vs. 6.0 vs. 6.0 vs. 5.5 (109/L); p = 0.007), lymphocytes (2.4 vs. 2.1 vs. 2.0 vs. 2.0 (109/L); p = 0.048), CRP (2.0 vs. 1.7 vs. 1.2 vs. 1.2 (mg/L); p = 0.037), and orosomucoid (0.82 vs. 0.77 vs. 0.76 vs. 0.70 (g/L); p = 0.015). After 150 days, no differences were detected in WBC counts or APRs between the vitamin D3 and the placebo group. However, vitamin D3 treated men had a higher prevalence of self-reported RTIs compared with the placebo group (55% vs. 39%; p = 0.005).

CONCLUSIONS

High-dose vitamin D3 supplementation did not alter WBCs or APRs, but a higher prevalence of respiratory infections was observed in the vitamin D3 group. Serum 25(OH)D3 was negatively correlated with most WBCs, indicating that vitamin D status may be linked with inflammation and WBC turnover, but not an important determinant of developing RTIs.

TRIAL REGISTRATION

NCT01304927 (ClinicalTrials.gov). Registered February 20, 2011.

Effects of sub-chronic exposure to microcystin-LR on the endocrine system of male rats

Microcystins (MCs) can cause reproductive and developmental toxicity and disrupt endocrine homeostasis in mammals. In the present study, male, Sprague-Dawley (SD) rats were administrated 3 or 30 μg MC-LR/kg, body mass (bm) per day via intraperitoneal (i.p.) injections for 6 weeks. Effects of MC-LR on histology, hormone concentrations, gene transcriptional profiles and protein expressions along the hypothalamic-pituitary-adrenal (HPA), -gonad (HPG) and -thyroid (HPT) axes were assessed. Sub-chronic administration with MC-LR caused histological damage to hypothalamus, pituitary, adrenal, testes and thyroid and affected relative masses of pituitary, adrenal and testes. The HPA axis was activated and serum concentrations of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were significantly augmented. Along the HPG axis, serum concentrations of gonadotropin-releasing hormone (GnRH) and dihydrotestosterone (DHT) were diminished, while concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) and estradiol (E2) were augmented. For the HPT axis, only concentrations of free tetra-iodothyronine (fT4) were significantly diminished, while concentrations of thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH) or free tri-iodothyronine (fT3) were not significantly changed. Also, several genes and proteins related to synthesis of steroid hormones were significantly altered. Findings of the present study illustrate that MC-LR can cause endocrine-disrupting effects through the disruption of synthesis and secretion of hormones along the HPA, HPG and HPT axes and negative feedback regulation. Also, there could be crosstalk among HPA, HPG and HPT axes. These findings elucidate mechanisms of endocrine-disrupting effects of MCs.

The association of medications and supplements with human male reproductive health: a systematic review

Some medications used to treat comorbidities and conditions in reproductive-aged individuals could have a negative impact on fertility. This may occur through hormonal disruption, toxicity to germ cells and spermatozoa, functional impact on the sperm, teratogenicity potential, or ejaculatory abnormalities. Having knowledge of these potential interactions between medications and reproductive potential is important for clinicians to be aware of and guide the patient, along with their treating clinicians, to reproductively favorable alternatives when available. This review aims to summarize the state of the literature regarding medication interactions with human male reproduction using the Anatomical Therapeutic Chemical Classification System of medications.

The role of the transsulfuration pathway in spermatogenesis of vitamin D deficient mice

Vitamin D deficiency is a global health problem and has been linked to defective spermatogenesis and male infertility. In this study, we aimed to investigate the main enzymes involved in the transsulfuration pathway of 1-carbon metabolism, and spermatogenesis function. Therefore, sixteen male C57 mice were addressed to a control (standard diet) or vitamin D deficient (VDD) diet for 14 weeks. The results show that compared to the standard diet, VDD increased final body weight and reduced sperm quality, caused damage to the testicular structure, and decreased the serum levels of testosterone. In addition, serum concentrations of homocysteine, vitamin B12, and sperm oxidative stress markers increased. In testicular tissues, the CBS and CSE protein levels were down-regulated whereas HO-1 was up-regulated at both mRNA and protein expression levels. Within a mice deprivation model, VDD deeply suppressed testosterone and impaired spermatogenesis with oxidative stress-mediated mechanisms. The effects of the deprivation appeared to be at least in part independent of genomic and receptor-mediated vitamin D actions and suggest a specific impairment of the alternative transsulfuration pathway.

VDR promotes testosterone synthesis in mouse Leydig cells via regulation of cholesterol side chain cleavage cytochrome P450 (Cyp11a1) expression

BACKGROUND

The vitamin D receptor (VDR) mediates the pleiotropic biological actions that include osteoporosis, immune responses and androgen synthesis.VDR is widely expressed in testis cells such as Leydig cells, Sertoli cells, and sperm. The levels of steroids are critical for sexual development. In the early stage of steroidogenesis, cholesterol is converted to pregnenolone (precursor of most steroid hormones) by cholesterol side-chain lyase (CYP11A1), which eventually synthesizes the male hormone testosterone.

OBJECTIVE

This study aims to reveal how VDR regulates CYP11A1 expression and affects testosterone synthesis in murine Leydig cells.

METHODS

The levels of VDR, CYP11A1 were determined by quantitative real-time polymerase chain reaction (RT-qPCR) or western blot. Targeted relationship between VDR and Cyp11a1 was evaluated by dual-luciferase reporter assay. The levels of testosterone concentrations in cell culture media serum by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Phylogenetic and motif analysis showed that the Cyp11a1 family had sequence loss, which may have special biological functions during evolution. The results of promoter prediction showed that vitamin D response element (VDRE) existed in the upstream promoter region of murine Cyp11a1. Dual-luciferase assay confirmed that VDR could bind candidate VDREs in upstream region of Cyp11a1, and enhance gene expression. Tissue distribution and localizatio analysis showed that Cyp11a1 was mainly expressed in testis, and dominantly existed in murine Leydig cells. Furthermore, over-expression VDR and CYP11A1 significantly increased testosterone synthesis in mice Leydig cells.

CONCLUSIONS

Active vitamin D3 (VD3) and Vdr interference treatment showed that VD3/VDR had a positive regulatory effect on Cyp11a1 expression and testosterone secretion. VDR promotes testosterone synthesis in male mice by up-regulating Cyp11a1 expression, which played an important role for male reproduction.

Anti-Aging Activity and Modes of Action of Compounds from Natural Food Sources

Aging is a natural and inescapable phenomenon characterized by a progressive deterioration of physiological functions, leading to increased vulnerability to chronic diseases and death. With economic and medical development, the elderly population is gradually increasing, which poses a great burden to society, the economy and the medical field. Thus, healthy aging has now become a common aspiration among people over the world. Accumulating evidence indicates that substances that can mediate the deteriorated physiological processes are highly likely to have the potential to prolong lifespan and improve aging-associated diseases. Foods from natural sources are full of bioactive compounds, such as polysaccharides, polyphenols, carotenoids, sterols, terpenoids and vitamins. These bioactive compounds and their derivatives have been shown to be able to delay aging and/or improve aging-associated diseases, thereby prolonging lifespan, via regulation of various physiological processes. Here, we summarize the current understanding of the anti-aging activities of the compounds, polysaccharides, polyphenols, carotenoids, sterols, terpenoids and vitamins from natural food sources, and their modes of action in delaying aging and improving aging-associated diseases. This will certainly provide a reference for further research on the anti-aging effects of bioactive compounds from natural food sources.

Effects of Vitamin D Supplementation on Testosterone, Prostate, and Lower Urinary Tract Symptoms: A Prospective, Comparative Study

PURPOSE

Several studies have associated the serum vitamin D level with total testosterone levels and the prostate volume. Herein, we investigated the effect of vitamin D supplementation on testosterone, prostate, and lower urinary tract symptoms (LUTS) in men.

MATERIALS AND METHODS

Men over 40 years of age diagnosed with a vitamin D deficiency (25[OH]D <20 ng/mL) who received vitamin D supplementation for one year were included in the study and administered 25,000 IU of cholecalciferol every 2 weeks. Prostate ultrasound, uroflowmetry, postvoid residual urine volume measurement, and serological tests (serum testosterone levels, etc.) were performed upon diagnosis and one year later. Participants also answered the International Prostate Symptom Score (IPSS) and Aging Males' Symptoms Scale (AMS) questionnaires.

RESULTS

A significant increase was observed in the vitamin D level following one year of vitamin D supplementation, with a significant decrease in the postvoid residual urine volume, total IPSS score and without a significant change in the prostate volume. Improved psychological subscale score of AMS questionnaire was observed with a statistical significance.

CONCLUSIONS

Vitamin D supplementation suppressed the increase in the prostate volume and improved the LUTS. Although there is no direct effect on serum testosterone levels, vitamin D supplementation helped improve hypogonadal symptoms.

Association Between Vitamin D Deficiency and Testosterone Levels in Adult Males: A Systematic Review

Vitamin D deficiency and its potential impact on testosterone levels have been subjects of scientific interest. This systematic review aims to evaluate the association between vitamin D deficiency and testosterone levels in adult males and examine the effects of vitamin D supplementation on testosterone. A comprehensive literature search was conducted in accordance with the PRISMA guidelines across PubMed, Google Scholar, and ScienceDirect. The inclusion criteria involved studies published in English between 2013 and 2023, which investigated the correlation between vitamin D and testosterone levels in adult males. The process of data extraction and synthesis encompassed various aspects, including study characteristics, participant demographics, measurement methods, and outcomes pertaining to the association. The initial search resulted in a pool of 354,235 articles. Through the application of relevant filters and the review of titles and abstracts, 48 articles were chosen for further assessment. Out of these, eight studies fulfilled the inclusion criteria and were ultimately incorporated into the final review. The included studies consisted of four cross-sectional studies, three randomized controlled trials (RCTs), and one analysis utilizing Mendelian randomization. The results showed heterogeneity among the studies, as some reported a positive correlation between vitamin D levels and testosterone, while others did not find a significant association. The effects of vitamin D supplementation on testosterone levels were inconclusive, with limited evidence of significant changes in total testosterone. However, potential influences on sex hormone-binding globulin and free testosterone levels were observed. To establish more definitive evidence regarding the impact of vitamin D on testosterone levels, there is a need for further well-designed, long-term RCTs that encompass diverse populations.

Effect of vitamin D metabolites and gene expression of vitamin D receptor, and 1-alpha-hydroxylase related to the sperm quality

The incidence of male fertility disorders has increased greatly due to various genetic and lifestyle factors. Recently, it has been hypothesized that vitamin D may be involved with idiopathic infertility. The goal of the study was to determine the effect and relationship between blood vitamin D metabolites, intracellular sperm vitamin D levels, and gene expression of 1-α-hydroxylase and VDR, with regard to semen quality. Seventy volunteers aged 25-45 were involved in the study. According to spermogram analysis, participants were stratified into normozoospermic control group, non-normozoospermic target group, and oligoasthenoteratozoospermic group. Vitamin D metabolites (total 25-hydroxycholecalciferol, 1,25-dihydroxycholecalciferol) in blood and spermatozoa were determined by ELISA. Free and bioavailable 25-hydroxycholecalciferol were calculated using the Vermeulen equation. mRNA expression of VDR and 1-α hydroxylase was evaluated by qPCR. Free and bioavailable 25-hydroxycholecalciferol were significantly higher in the control group compared to the target group and compared to the oligoasthenoteratozoospermic group . Intracellular sperm 1,25-dihydroxycholecalciferol was higher in the control group compared to the target group. The mRNA levels of 1- α-hydroxylase were significantly higher in the control samples, while VDR expression was significantly higher in the target group. Significant positive correlations were established between free and bioavailable 25-hydroxycholecalciferol with sperm motility and morphology. Vitamin D metabolites in blood and intracellular sperm 1,25-dihydroxycholecalciferol seem to exert beneficial effects on sperm motility and morphology. Regarding sperm quality, these effects are more pronounced in the free and bioavailable 25OHD compared to the total 25OHD in blood. Higher expression of 1-α-hydroxylase likely leads to higher intracellular levels of 1,25-dihydroxycholecalciferol, which could contribute to sperm motility and morphology. Higher VDR expression may be a compensatory mechanism related to lower intracellular sperm 1,25-dihydroxycholecalciferol.

Assessment of Vitamin D Levels and Other Bone Related Biochemical Markers in Healthy Adults in Rural Population of Uttarakhand, India

Despite being close to equator and receiving sufficient sun rays, evidences revealed that Indians have severe deficiency of vitamin D (vit D) ranging from 41 to 100% in different geographical locations. Therefore, in this study levels of 25(OH)D (physiologically measurable form) along with other bone metabolism associated biochemical markers were determined in serum sample of 300 apparently healthy study subjects (rural) from Doiwala block of Dehradun district in the state of Uttarakhand. Demographic data was also obtained based on a structured questionnaire to establish an association between 25(OH)D levels and various dietary and socio-cultural factors. Results demonstrated that of all study subjects, 197 (65%) had 25(OH)D levels below < 12 ng/mL (deficient) and 65 (21%) had 25(OH)D levels between 12 and 20 ng/mL (insufficient) with all other markers falling within respectively established reference ranges. Further, in univariate analysis, gender, occupation (indoor and outdoor), education were independently associated with vitamin D status. Additionally, parathyroid hormone associated significantly with gender and occupation, while calcium associated significantly with gender, occupation and education. Lastly, regression analysis revealed that gender and occupation independently associated with vitamin D status of subjects. In conclusion, apparently healthy subjects showed considerable vitamin D deficiency thereby generating an urgent need for formulating and implementing better government policies for enrichment of vitamin D levels among rural adults of Uttarakhand in future.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-022-01048-6.

Mechanisms Suggesting a Relationship between Vitamin D and Erectile Dysfunction: An Overview

Vitamin D deficiency (VDD) and erectile dysfunction (ED) heavily burden the male population. The higher prevalence of both conditions in the elderly suggests a possible relationship between the two conditions. In addition, in vitro, animal, and human studies have revealed several mechanisms that may relate VDD to ED. The main mechanism by which vitamin D might exert its action on sexual function appears to be through the regulation of endothelial function. Indeed, VDD correlates with several markers of endothelial function. The action of vitamin D on the endothelium would be exercised both indirectly through its intervention in inflammatory processes and through the production of oxygen free radicals, and directly through the regulation of vascular stiffness, the production of nitric oxide, and the regulation of vessel permeability. Furthermore, the ubiquitous distribution of the vitamin D receptor in the human body means that this hormone can also exert a beneficial effect on erectile function by interfering with those comorbidities significantly associated with ED, such as hypertension, diabetes mellitus, hypercholesterolemia, chronic kidney disease, and hypogonadism. In this review, we thoroughly and carefully presented the evidence and mechanisms that would appear to relate vitamin D levels to erectile function. Furthermore, we have summarized the meta-analytic evidence for and against this association to provide a true representation of this topic. Data published to date suggest that low levels of vitamin D could contribute to worsening erectile function through several mechanisms. Therefore, vitamin D levels should be measured in patients with ED and maintained at adequate levels by specific supplementation in case of deficiency. However, the low quality and heterogeneity of clinical trials evaluating the effects of vitamin D administration on erectile function and ED-associated comorbidities do not allow for a univocal conclusion, and indicate the need for further studies to analyze these aspects.

Isochromosome 12p Formation Regulates Vitamin D Metabolism in Testicular Cancer

Isochromosome 12p (iChr12p) is typical in almost all invasive testicular cancers. Increased copy number of genes on 12p is associated with the development of a clinically manifest tumor; however, the causative genes have not yet been identified. Chromosome 12 harbors many genes involved in Vitamin D metabolism. RNAseq analysis of Vitamin D receptor (VDR) genes from the TCGA cohort revealed that clustering of VDR expression signatures could differentiate between pure seminomas and non-seminomatous germ cell tumors (NSGCT). Using TCGA mRNA expression of anabolic (CYP2R1, CYP27A1 and CYP27B1) and catabolic (CYP24A1) Vitamin D enzymes, positive (PTHLH, IFNG, and TNF) and negative (FGF23) feedback regulators could also clearly distinguish between pure seminomas and NSGCT. We hypothesize that the regulation of Vitamin D metabolism might be disturbed through iChr12p formation, influencing testicular carcinogenesis via increased FGF23 and PTHLH expression. While FGF23 represses CYP27B1 and activates catabolism of active hormone, increased PTHLH secretion can lead to hypercalcemia via inactivation of VDR. In conclusion, testicular cancer is associated with extensive modifications in intratesticular Vitamin D homeostasis. Further research is needed to clarify whether Vitamin D deficiency causes the formation of iChr12p and whether Vitamin D deficiency via iChr12p genomic aberration is involved in testicular carcinogenesis.

Vitamin D and in vitro fertilization: a systematic review

PURPOSE

Vitamin D (VD) action on calcium is well known, but its other properties, particularly in the human reproductive system, are not completely understood. This review aims at assessing the relationship between serum VD levels and IVF results.

METHODS

A systematic review was carried out using MEDLINE, EMBASE, LILACS, Google scholar, the CAPES journal portal, and the Cochrane Library, as well as the descriptors "vitamin D" and "fertilization in vitro." The review was conducted by two authors following the PRISMA recommendations between September 2021 and February 2022.

RESULTS

Eighteen articles were selected. Five of them showed a positive correlation between serum VD levels and IVF results, 12 lacked any association, and 1 exhibited a negative correlation. The 3 studies that assessed VD in the follicular fluid found a positive correlation between the serum and follicular levels. Non-Hispanic White patients seemed to suffer the consequence of vitamin D deficiency more than Asian patients. In one study alone in the VD-deficient group, there was a larger number of natural killer (NK) cells, B cells, a greater proportion of helper T cells/cytotoxic T cells (Th/Tc), and an association with a smaller number of mature oocytes.

CONCLUSION

The association between serum VD levels and the post-IVF pregnancy rate is uncertain. However, VD levels might be more relevant in the White than in the Asian ethnicity and in the number of aspiration follicles, and they could act in the immune system having an impact both on embryo implantation and on pregnancy.

Roles of sex hormones in mediating the causal effect of vitamin D on osteoporosis: A two-step Mendelian randomization study

Background

Although 25-hydroxyvitamin D [25(OH)D] is a risk factor for osteoporosis, it is not clear whether sex hormones mediate this casual association. We aimed to explore how sex hormones affect the association between 25(OH)D and osteoporosis to provide meaningful insights on the underlying mechanisms from a genetic perspective.

Methods

Genetic variations in 25(OH)D, total testosterone (TT), androstenedione (A4), estradiol (E2), and testosterone/17β-estradiol (T/E2) were determined through summary statistics. Taking osteoporosis as the outcome (FinnGen biobank, 332,020 samples), we conducted a Mendelian randomization (MR) analysis to establish the association between 25(OH)D and these sex hormones. The two-step MR analysis quantified the mediatory effects of sex hormones on osteoporosis. The results were further verified by pleiotropy and heterogeneity analyses.

Results

MR results showed that 25(OH)D (OR= 1.27, p = 0.04) and TT (OR= 1.25, p = 0.04) had a causal effect on osteoporosis. No significant associations were observed between the other sex hormones (A4, E2, and T/E2) and osteoporosis (p&gt;0.05). Sensitivity analysis (p&gt;0.05) confirmed the robustness of the MR results. The two-step MR analysis provided evidence that the mediatory effect of TT was 0.014 (the percentage of TT mediation was 5.91%). Moreover, the direct effect of 25(OH)D on osteoporosis was 0.221. A4, E2, and T/E2 were not considered as potential mediators of the role of 25(OH)D as a risk factor for OP.

Conclusion

This study, through MR analysis, showed that TT mediates the causal effect of 25(OH)D on osteoporosis. Interventions targeting TT, therefore, have the potential to substantially reduce the burden of osteoporosis attributable to high 25(OH)D.

The Association between Vitamin D and the Components of Male Fertility: A Systematic Review

OBJECTIVE

Previous systematic reviews of the effects of vitamin D on the components of male fertility have been inconclusive. This article systematically reviews the latest research to examine the relationship between vitamin D, semen quality parameters, and sex hormones production.

METHODS

MEDLINE, Cochrane, and Web of Science databases were searched using the appropriate keywords.

RESULTS

Observational studies indicate significant correlation between vitamin D levels and sperm parameters, with a particular emphasis on sperm motility, and partially suggest a relationship between higher serum testosterone and vitamin D levels. Additionally, interventional studies confirmed that vitamin D supplementation has a positive effect on sperm motility, especially progressive. However, most randomized clinical trials indicate that vitamin D treatment does not have any significant effect on testosterone or other hormone levels.

CONCLUSIONS

Although our findings add to the discussion regarding the effect of vitamin D on male fertility, there is still no solid evidence to support the use of vitamin D supplementation to improve the outcomes of patients with impaired sperm parameters and hormonal disorders. Additional dedicated clinical studies are needed to clarify the relationship between vitamin D and male fertility, along with its components.

Linagliptin and Vitamin D3 Synergistically Rescue Testicular Steroidogenesis and Spermatogenesis in Cisplatin-Exposed Rats: The Crosstalk of Endoplasmic Reticulum Stress with NF-κB/iNOS Activation

This study investigated the therapeutic effect of linagliptin and/or vitamin D3 on testicular steroidogenesis and spermatogenesis in cisplatin-exposed rats including their impact on endoplasmic reticulum (ER) stress and NF-κB/iNOS crosstalk. Cisplatin (7 mg/kg, IP) was injected into adult male albino rats which then were orally treated with drug vehicle, linagliptin (3 mg/kg/day), vitamin D3 (10 μg/kg/day) or both drugs for four weeks. Age-matched rats were used as the control group. Serum samples and testes were collected for further analyses. Cisplatin induced testicular weight loss, deteriorated testicular architecture, loss of germ cells and declined serum and intra-testicular testosterone levels, compared to the control group. There was down-regulation of steroidogenic markers including StAR, CYP11A1, HSD3b and HSD17b in cisplatin-exposed rats, compared with controls. Cisplatin-exposed rats showed up-regulation of ER stress markers in testicular tissue along with increased expression of NF-κB and iNOS in spermatogenic and Leydig cells. These perturbations were almost reversed by vitamin D3 or linagliptin. The combined therapy exerted a more remarkable effect on testicular dysfunction than either monotherapy. These findings suggest a novel therapeutic application for linagliptin combined with vitamin D3 to restore testicular architecture, aberrant steroidogenesis and spermatogenesis after cisplatin exposure. These effects may be attributed to suppression of ER stress and NF-kB/iNOS.

Vitamin D and Male Reproduction: Updated Evidence Based on Literature Review

The purpose of this study was to clarify the vitamin D (VD) effect on male infertility. Our research was conducted using the following electronic databases: MEDLINE, Embase, Web of Science, Scopus, ClinicalTrials.gov, and Cochrane Library. Selection criteria included all published randomized controlled trials and non-randomized studies, focusing on vitamin D and male reproductive function. The results showed that the effects of VD on male reproduction has been investigated in three different topics: the molecular mechanism underlying VD effects on semen quality (SQ), the relationship between VD levels and SQ, and the effect of VD supplementation on SQ. Results supported the hypothesis of a relevant interrelation between concentrations of male VD and semen parameters, with particular reference to sperm motility; on the contrary, evidence on the effect of VD on male sex steroid hormone levels was inconclusive. The results of this review hold up the thesis that VD plays a role in male reproduction. Most of the data highlighted a positive effect on semen quality, particularly in sperm motility, both in fertile and infertile men. Additional dedicated studies are required to elucidate the still controversial aspects of this topic.

Vitamin D Receptor affects male mouse fertility via regulation of lipid metabolism and testosterone biosynthesis in testis

Vitamin D and vitamin D receptor (VD/VDR) plays a vital role in the development of spermatozoa, which is largely determined by the testosterone level in serum. Testosterone biosynthesis is closely related to lipid metabolism in gonadal adipose around testes. VDR could regulate lipid metabolism in adipocytes as well. However, it still remains unknown how VDR regulates lipid metabolism to impact testosterone biosynthesis in testis. Hereby, various parameters of male fertility were compared between wildtype (WT) and Vdr knockout (Vdr-KO) male mouse. For Vdr-KO mice, the size of testis and gonadal adipose was smaller than that of WT, and the sperm quality and testosterone level were lower than WT. Subsequently, testis proteome data between Vdr-KO and WT mice indicated that dysregulation of lipid metabolism was closely associated with decreased testosterone biosynthesis in Vdr-deficient mouse. And further evaluation of VDR functions in Leydig cells verified that VDR impacted lipid metabolism and regulated the expression of a range of genes involved in testosterone biosynthesis. Knockdown VDR could significantly decrease testosterone synthesis and secretion in Leydig cells. Meanwhile, expression of genes involved in androgen synthesis was decreased but genes related to lipolysis were up-regulated. Collectively, the present study unveiled the relationship between lipid metabolism and testosterone biosynthesis mediated by VDR in mouse testis and its effect on male fertility. These findings will greatly enhance our current understanding of VDR intermediate in lipid metabolism and androgen synthesis.

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.

Effect of Paternal Diet on Spermatogenesis and Offspring Health: Focus on Epigenetics and Interventions with Food Bioactive Compounds

Infertility is a growing public health problem. Consumption of antioxidant bioactive food compounds (BFCs) that include micronutrients and non-nutrients has been highlighted as a potential strategy to protect against oxidative and inflammatory damage in the male reproductive system induced by obesity, alcohol, and toxicants and, thus, improve spermatogenesis and the fertility parameters. Paternal consumption of such dietary compounds could not only benefit the fathers but their offspring as well. Studies in the new field of paternal origins of health and disease show that paternal malnutrition can alter sperm epigenome, and this can alter fetal development and program an increased risk of metabolic diseases and breast cancer in adulthood. BFCs, such as ascorbic acid, α-tocopherol, polyunsaturated fatty acids, trace elements, carnitines, N-acetylcysteine, and coenzyme Q10, have been shown to improve male gametogenesis, modulate epigenetics of germ cells, and the epigenetic signature of the offspring, restoring offspring metabolic health induced by stressors during early life. This indicates that, from a father’s perspective, preconception is a valuable window of opportunity to start potential nutritional interventions with these BFCs to maximize sperm epigenetic integrity and promote adequate fetal growth and development, thus preventing chronic disease in adulthood.

VDR mediated HSD3B1 to regulate lipid metabolism and promoted testosterone synthesis in mouse Leydig cells

BACKGROUND

The vitamin D receptor (VDR) mediates the pleiotropic biological actions that include osteoporosis, immune responses and androgen synthesis wherein the VDR transcriptionally regulates expression of the genes involved in this complex process. 3β-Hydroxysteroid dehydrogenase-1 (HSD3B1) is an absolutely necessary enzyme for androgen synthesis.

OBJECTIVE

The purpose of the present study was to explore the molecular mechanism of VDR mediated HSD3B1 regulation of lipid metabolism and testosterone synthesis.

METHODS

The levels of VDR, HSD3B1 and lipid metabolism associated protein were determined by quantitative real-time polymerase chain reaction (RT-qPCR) or western blot. The levels of testosterone concentrations in cell culture media serum by enzyme-linked immunosorbent assay (ELISA). Targeted relationship between VDR and Hsd3b1 was evaluated by dual-luciferase reporter assay.

RESULTS

Based on the data analysis of mouse testicular proteome, we found that the expression of HSD3B1 was significantly reduced after VDR deletion. Here, we identified that Hsd3b1 was widely expressed in different tissues of mice by RT-qPCR, and was highly expressed in testis, and mainly located in testicular Leydig cells. Dual-luciferase assay confirmed that VDR could bind candidate vitamin D responsive elements (VDREs) in upstream region of Hsd3b1, and enhance gene expression. Furthermore, over-expression VDR and HSD3B1 significantly increased testosterone synthesis in mice Leydig cells. Meanwhile, Lpl expression was significantly down-regulated and Angptl4 expression was significantly up-regulated in the present of HSD3B1 overexpression. Both LPL and ANGPTL4 play important roles in regulating lipid metabolism.

CONCLUSIONS

The present study unveiled VDR mediated HSD3B1 to regulate lipid metabolism and promoted testosterone synthesis in mouse Leydig cells. These findings will greatly help us to understand the roles of VDR and HSD3B1 in testosterone synthesis and lipid metabolism.

Vitamin D: Before, during and after Pregnancy: Effect on Neonates and Children

A worldwide high prevalence of vitamin D (VD) deficiency has become of growing concern because of potential adverse effects on human health, including pregnant women and their offsprings. Beyond its classical function as a regulator of calcium and phosphate metabolism, together with its fundamental role in bone health in every stage of life, its deficiency has been associated to multiple adverse health effects. The classic effects of VD deficiency in pregnancy and neonates have been late hypocalcemia and nutritional rickets. Nevertheless, recent studies have linked VD to fertility and 25(OH)D with several clinical conditions in pregnancy: preeclampsia, gestational diabetes, higher incidence of cesarean section and preterm birth, while in infants, the clinical conditions are low birth weight, lower bone mass and possible relationship with the development of such diseases as bronchiolitis, asthma, type 1 diabetes, multiple sclerosis and autism included as VD non-classical actions. The supplementation with Vitamin D and achievement of optimal levels reduce maternal-fetal and newborn complications. Supplementation in children with VD deficiency reduces the risk of respiratory infections and possibly autoimmune diseases and autism. This review emphasizes the roles of Vitamin D deficiency and the consequences of intervention from preconception to infancy.

Investigation of equine testis contribution to vitamin D bioactivation

Although vitamin D acts in various biological processes, it plays a critical role in the maintenance of bone health, and regulates calcium homeostasis. In humans and rodents, the main tissues involved in vitamin D metabolism are the liver and the kidneys, however it has been shown that the testis has strongly participated in its bioactivation. Indeed, in these different species, enzymes metabolizing vitamin D (CYP27A1, CYP27B1 and CYP2R1) have been demonstrated in this tissue. Moreover, men with hypogonadism have shown a decrease in circulating levels of vitamin D. In equine species, the castration of males is a regular practice to reduce the behavior of stallions deemed too aggressive. Castration is carried out at various ages: in foals during their growth or in adulthood once they have reached their optimum size. Although horses exhibit atypical vitamin D metabolism with low circulating levels of vitamin D, it was suggested that testis may contribute to its activation as has been described in rodents and humans; castration could therefore be likely to affect its metabolism. In this study, blood levels of bioactive form of vitamin D (1 α,25[OH] 2 vitamin D 3 ) were measured before and after castration at different ages: 1 wk, after puberty (2 yr) and at adulthood (6 yr). The gene expression of enzymes involved in vitamin D metabolism has been sought in the testis of different experimental groups. No change in bioactive vitamin D3 levels was observed after castration regardless of the age at the time of surgery. The exceptional status of equine species is confirmed with a low or a lack of testis contribution to vitamin D metabolism, regardless of testicular development. This is demonstrated by a low or a lack of signal from enzymes involved in vitamin D bioactivation. Therefore, horses constitute a unique model in comparative endocrinology.

Calcium Homeostasis in the Epididymal Microenvironment: Is Extracellular Calcium a Cofactor for Matrix Gla Protein-Dependent Scavenging Regulated by Vitamins

In the male reproductive tract, the epididymis is an essential organ for sperm maturation, in which sperm cells acquire mobility and the ability to fertilize oocytes while being stored in a protective microenvironment. Epididymal function involves a specialized luminal microenvironment established by the epithelial cells of epididymal mucosa. Low-calcium concentration is a unique feature of this epididymal luminal microenvironment, its relevance and regulation are, however, incompletely understood. In the rat epididymis, the vitamin D-related calcium-dependent TRPV6-TMEM16A channel-coupler has been shown to be involved in fluid transport, and, in a spatially complementary manner, vitamin K2-related γ-glutamyl carboxylase (GGCX)-dependent carboxylation of matrix Gla protein (MGP) plays an essential role in promoting calcium-dependent protein aggregation. An SNP in the human GGCX gene has been associated with asthenozoospermia. In addition, bioinformatic analysis also suggests the involvement of a vitamin B6-axis in calcium-dependent MGP-mediated protein aggregation. These findings suggest that vitamins interact with calcium homeostasis in the epididymis to ensure proper sperm maturation and male fertility. This review article discusses the regulation mechanisms of calcium homeostasis in the epididymis, and the potential role of vitamin interactions on epididymal calcium homeostasis, especially the role of matrix calcium in the epididymal lumen as a cofactor for the carboxylated MGP-mediated scavenging function.

Factors Defining the Association Between Vitamin D and Testosterone in Males With Type 2 Diabetes and Hypogonadism

OBJECTIVE

This study aimed to evaluate Serum 25-hydroxyvitamin D (25[OH]D) levels in diabetic men with and without hypogonadism and figured out the potential factors influencing the connection between vitamin D and testosterone.

METHODS

A total of 367 men with type 2 diabetes mellitus (T2DM) were investigated, including 254 men with normal gonadal function (Group 1) and 113 men with hypogonadism (Group 2). Men with hypogonadism were classified as either hypogonadotropic hypogonadism (Group 2a) or hypergonadotropic hypogonadism (Group 2b). Serum 25(OH)D levels were detected by liquid chromatography-tandem mass spectrometry in all cases. Morning total testosterone (TT), estradiol (E), dehydroepiandrosterone (DHEA), prolactin (PRL), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid function, parathyroid and adrenal hormones, fasting blood glucose (FBG), fasting insulin (Fins) and hemoglobin A1c (HbA1c) were also assessed.

RESULTS

The prevalence of hypovitaminosis D in men with T2DM was up to 96.46%. Serum 25(OH)D levels were significantly lower in men with hypogonadism than those with eugonadism (16.65 ± 6.44 ng/mL vs. 18.17 ± 6.17 ng/mL, P=0.033). The lowest 25(OH)D level was observed in Group 2a (16.22 ± 6.52 ng/mL). After adjustment for the selected factors, serum 25(OH)D concentrations were shown to be positively correlated with TT concentrations (r=0.137, P=0.032). The relationship between 25(OH)D and testosterone was altered by age, duration of T2DM, body mass index, and HbA1c. Serum 25(OH)D level was positively associated with serum TT level in men with age <60 years (r=0.180, P=0.003), or with duration≥5 years (r=0.186, P=0.013), or with body mass index (BMI)≥28kg/m² (r=0.431, P=0.000), or with HbA1c≥9% (r=0.145, P=0.031).

CONCLUSIONS

These findings indicate that type 2 diabetes patients with hypogonadism have lower 25(OH)D levels than those without hypogonadism. There seems to be a positive association between the serum 25(OH)D and TT levels, which affected by age, duration, BMI, and HbA1c.