Search Results

You are looking at 1 - 7 of 7 items for

  • Author: Barbara Obermayer-Pietsch x
  • Refine by Access: Content accessible to me x
Clear All Modify Search
Free access

Elisabeth Lerchbaum and Barbara Obermayer-Pietsch

Background

Vitamin D has been well-known for its function in maintaining calcium and phosphorus homeostasis and promoting bone mineralization. There is some evidence that in addition to sex steroid hormones, the classic regulators of human reproduction, vitamin D also modulates reproductive processes in women and men.

Aim

The aim of this review was to assess the studies that evaluated the relationship between vitamin D and fertility in women and men as well as in animals.

Methods

We performed a systematic literature search in Pubmed for relevant English language publications published until October 2011.

Results and discussion

The vitamin D receptor (VDR) and vitamin D metabolizing enzymes are found in reproductive tissues of women and men. Vdr knockout mice have significant gonadal insufficiency, decreased sperm count and motility, and histological abnormalities of testis, ovary and uterus. Moreover, we present evidence that vitamin D is involved in female reproduction including IVF outcome (clinical pregnancy rates) and polycystic ovary syndrome (PCOS). In PCOS women, low 25-hydroxyvitamin D (25(OH)D) levels are associated with obesity, metabolic, and endocrine disturbances and vitamin D supplementation might improve menstrual frequency and metabolic disturbances in those women. Moreover, vitamin D might influence steroidogenesis of sex hormones (estradiol and progesterone) in healthy women and high 25(OH)D levels might be associated with endometriosis. In men, vitamin D is positively associated with semen quality and androgen status. Moreover, vitamin D treatment might increase testosterone levels. Testiculopathic men show low CYP21R expression, low 25(OH)D levels, and osteoporosis despite normal testosterone levels.

Free access

Verena Schwetz, Thomas Pieber, and Barbara Obermayer-Pietsch

Based on the observation that diabetes, obesity, and hypogonadism influence bone metabolism, the existence of a feedback loop and a common regulation was postulated and an endocrine role ascribed to the skeleton. In the first part of this review, two pathways are described whereby adipose tissue acts on bone mass. In the first, leptin activates the sympathetic nervous system via serotonin and diminishes bone mass accrual. The second pathway functions via the activation of CART (CARTPT) and inhibits bone resorption. The first pathway leads to a decrease in bioactivity of the osteoblast-produced hormone osteocalcin (OC) (part 2). In its undercarboxylated form, OC acts on the three targets pancreas, adipose tissue, and gonads (part 3) and thereby causes an increase in insulin secretion and sensitivity, β-cell proliferation, and male fertility. Insulin (part 4) is part of a recently discovered regulatory feedback loop between pancreas and osteoblasts. It is a strong counterplayer of leptin as it causes a decrease in OPG expression and enhances bone resorption and OC decarboxylation. Numerous clinical studies (part 5) have shown associations of total and undercarboxylated OC and markers of energy metabolism. Interventional studies, to date only performed in murine models, have shown positive effects of OC administration on energy metabolism. Whether bone tissue has an even further-reaching endocrine role remains to be elucidated.

Free access

Elisabeth Lerchbaum, Verena Schwetz, Albrecht Giuliani, and Barbara Obermayer-Pietsch

Objective

There is evidence suggesting a strong genetic background of polycystic ovary syndrome (PCOS). We aim to study the metabolic and endocrine characteristics of PCOS women with and without a family history (FHx) of type 2 diabetes mellitus (T2DM) and PCOS.

Design

Cross-sectional study.

Methods

We analysed the association of T2DM FHx and PCOS FHx with metabolic and endocrine parameters in 714 PCOS women.

Results

A positive FHx of T2DM and PCOS were prevalent in 36.8 and 21.4% of PCOS women respectively. We found an independent association of T2DM FHx with central fat accumulation, obesity, prediabetes, metabolic syndrome (MS), insulin resistance, low HDL and elevated blood pressure (P<0.05 for all). PCOS FHx was independently associated with prediabetes (P<0.05). We observed an independent association of PCOS FHx with clinical and biochemical hyperandrogenism (P<0.05 for all), whereas there was no independent association of T2DM FHx with hyperandrogenism. PCOS women with a positive FHx of both T2DM and PCOS had an adverse metabolic and endocrine profile including a linear increase in risk of obesity, central fat accumulation, MS, prediabetes and low HDL (P<0.05 for all).

Conclusions

Our findings suggest that the assessment of FHx might allow risk stratification of PCOS women, which is important considering the high prevalence of PCOS.

Free access

Simona Gaberšček, Katja Zaletel, Verena Schwetz, Thomas Pieber, Barbara Obermayer-Pietsch, and Elisabeth Lerchbaum

Thyroid disorders, especially Hashimoto's thyroiditis (HT), and polycystic ovary syndrome (PCOS) are closely associated, based on a number of studies showing a significantly higher prevalence of HT in women with PCOS than in controls. However, the mechanisms of this association are not as clear. Certainly, genetic susceptibility contributes an important part to the development of HT and PCOS. However, a common genetic background has not yet been established. Polymorphisms of the PCOS-related gene for fibrillin 3 (FBN3) could be involved in the pathogenesis of HT and PCOS. Fibrillins influence the activity of transforming growth factor beta (TGFβ). Multifunctional TGFβ is also a key regulator of immune tolerance by stimulating regulatory T cells (Tregs), which are known to inhibit excessive immune response. With lower TGFβ and Treg levels, the autoimmune processes, well known in HT and assumed in PCOS, might develop. In fact, lower levels of TGFβ1 were found in HT as well as in PCOS women carrying allele 8 of D19S884 in the FBN3 gene. Additionally, vitamin D deficiency was shown to decrease Tregs. Finally, high estrogen-to-progesterone ratio owing to anovulatory cycles in PCOS women could enhance the immune response. Harmful metabolic and reproductive effects were shown to be more pronounced in women with HT and PCOS when compared with women with HT alone or with controls. In conclusion, HT and PCOS are associated not only with respect to their prevalence, but also with regard to etiology and clinical consequences. However, a possible crosstalk of this association is yet to be elucidated.

Free access

Elisabeth Wehr, Olivia Trummer, Albrecht Giuliani, Hans-Jürgen Gruber, Thomas R Pieber, and Barbara Obermayer-Pietsch

Introduction

Women with polycystic ovary syndrome (PCOS) frequently suffer from metabolic disturbances including insulin resistance (IR), which might be related to vitamin D metabolism. We aimed to investigate the association of polymorphisms in the vitamin D receptor (VDR) gene as well as vitamin D level-associated genes with metabolic and endocrine parameters in PCOS women. Moreover, we examined whether there are associations with PCOS susceptibility.

Methods

Metabolic, endocrine, and anthropometric measurements and oral glucose tolerance tests were performed in 545 PCOS and 145 control women. Genotyping of VDR (Cdx2, Bsm-I, Fok-I, Apa-I, and Taq-I), GC, DHCR7, and CYP2R1 polymorphisms was performed.

Results

25-Hydroxyvitamin D (25(OH)D) levels showed significant negative correlation with IR and positive correlation with insulin sensitivity (P<0.05 for all) in PCOS women. In PCOS women, the VDR Cdx2 ‘AA’ genotype was associated with lower fasting insulin (P=0.039) and homeostatic model assessment-IR (P=0.041) and higher quantitative insulin-sensitivity check index (P=0.012) and MATSUDA index (P=0.003). The VDR Apa-I ‘AA’ genotype was associated with lower testosterone (P=0.028) levels. In PCOS women, 170 women (31.2%) presented with 25(OH)D levels <20 ng/ml. PCOS women carrying the GC ‘GG’ genotype and the DHCR7 ‘GG’ genotype had a significantly higher risk for 25(OH)D levels <20 ng/ml (OR 2.53 (1.27–5.06), P=0.009, and OR 2.66 (1.08–6.55), P=0.033 respectively) compared with PCOS women carrying the GC ‘TT’ genotype and DHCR ‘TT’ genotype in multivariate analyses. We observed no association of genetic variations and PCOS susceptibility.

Conclusion

VDR and vitamin D level-related variants are associated with metabolic and endocrine parameters including 25(OH)D levels in PCOS women.

Free access

Elisabeth Lerchbaum, Hans-Jürgen Gruber, Verena Schwetz, Albrecht Giuliani, Reinhard Möller, Thomas R Pieber, and Barbara Obermayer-Pietsch

Introduction

Women with polycystic ovary syndrome (PCOS) frequently suffer from metabolic disturbances and might be affected by hepatic steatosis. The fatty liver index (FLI) was developed as a simple and accurate predictor of hepatic steatosis. We aimed to analyze the association of FLI with endocrine and metabolic parameters in a cohort of PCOS and control women.

Methods

FLI was calculated using body mass index (BMI), waist circumference, triglycerides, and gamma-glutamyl transferase in 611 PCOS and 139 BMI-matched control women within the same age range. Elevated FLI was defined as >60. Metabolic, endocrine, and anthropometric measurements and oral glucose tolerance tests were performed.

Results

PCOS women had significantly higher FLI levels than control women in age-adjusted analyses (11.4 (4.3–48.8) and 8.8 (3.9–35.0), respectively, P=0.001), whereas fibrosis indices were similar (aspartate amino transferase-to-platelet ratio index) or lower (FIB-4) respectively. In binary logistic regression analysis adjusted for age, odds ratio (OR) for elevated FLI was 2.52 (1.31–4.85), P=0.006, for PCOS women when compared with controls. PCOS women with high FLI levels had an adverse anthropometric, metabolic, and endocrine risk profile. The prevalence of elevated FLI was 88.7% in PCOS women with metabolic syndrome (MS) and 11.3% in PCOS women without MS (P<0.001). In control women, elevated FLI was present in 66.7% of women with MS and 30.8% of women without MS.

Conclusion

High FLI levels are a common finding in obese PCOS women and are closely linked to MS. FLI calculation might be a useful tool for identifying PCOS patients at high risk for metabolic and hepatic disturbances.

Free access

Paul Lips, Kevin D Cashman, Christel Lamberg-Allardt, Heike Annette Bischoff-Ferrari, Barbara Obermayer-Pietsch, Maria Luisa Bianchi, Jan Stepan, Ghada El-Hajj Fuleihan, and Roger Bouillon

Vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) <50 nmol/L or 20 ng/mL) is common in Europe and the Middle East. It occurs in <20% of the population in Northern Europe, in 30–60% in Western, Southern and Eastern Europe and up to 80% in Middle East countries. Severe deficiency (serum 25(OH)D <30 nmol/L or 12 ng/mL) is found in >10% of Europeans. The European Calcified Tissue Society (ECTS) advises that the measurement of serum 25(OH)D be standardized, for example, by the Vitamin D Standardization Program. Risk groups include young children, adolescents, pregnant women, older people (especially the institutionalized) and non-Western immigrants. Consequences of vitamin D deficiency include mineralization defects and lower bone mineral density causing fractures. Extra-skeletal consequences may be muscle weakness, falls and acute respiratory infection, and are the subject of large ongoing clinical trials. The ECTS advises to improve vitamin D status by food fortification and the use of vitamin D supplements in risk groups. Fortification of foods by adding vitamin D to dairy products, bread and cereals can improve the vitamin D status of the whole population, but quality assurance monitoring is needed to prevent intoxication. Specific risk groups such as infants and children up to 3 years, pregnant women, older persons and non-Western immigrants should routinely receive vitamin D supplements. Future research should include genetic studies to better define individual vulnerability for vitamin D deficiency, and Mendelian randomization studies to address the effect of vitamin D deficiency on long-term non-skeletal outcomes such as cancer.