In the last decade, vitamin D was in the spotlight in many fields of research. Despite numerous publications, its influence on reproductive health remains ambiguous. This paper presents an up-to-date review of current knowledge concerning the role of cholecalciferol in human reproduction. It covers various infertility issues, such as polycystic ovary syndrome, endometriosis, myoma-induced infertility, male infertility, premature ovary failure and in vitro fertilization techniques. Vitamin D deficiency, defined as serum concentration of 25-hydroxycalciferol of less than 50 nmol/L, is commonly noted more frequently than only in fertility clinic patients. It is a global trend that is observed in all age groups. The results of original publications dated up to 2015 have been summarized and discussed in a critical manner. Most experts agree that vitamin D supplementation is a necessity, particularly in women suffering from obesity, insulin resistance or small ovarian reserve, as well as in men with oligo- and asthenozoospermia if serum concentration should fall below 50 nmol/L (normal range up to 125 nmol/L). High concentration of vitamin D and its metabolites in decidua during the 1st trimester suggests its important role in the implantation process and a local immunological embryo-protection. On the other hand, evidence-based research did not prove a significant difference so far in ovulation stimulation or embryo development depending on vitamin D level. In one of the publications, it was also found that vitamin D binding protein (VDBP) has a molecular similarity to anti-sperm antibodies, and another one concluded that both low (125 nmol/L) concentration of vitamin D are associated with decreased number and quality of spermatozoa in semen. Vitamin D is definitely not a Trojan Horse in reproductive health, since there were no adverse effects reported for vitamin D intake of up to 10,000 IU/day, but to proclaim it the Golden Fleece, more evidence is needed.

Endometriosis is a common gynaecological disorder characterized by the ectopic growth of endometrial tissue outside the uterine cavity. It is associated with chronic pelvic inflammation and autoimmune reactivity manifesting by autoantibody production and abrogated cellular immune responses. Endometriotic peritoneal fluid contains various infiltrating leucocyte populations and a bulk of proinflammatory and immunoregulatory cytokines. However, the nature and significance of the peritoneal milieu in women with endometriosis still remains obscure. Therefore, the aim of the present study was to investigate the immunoregulatory activity of the peritoneal fluid (PF) from women with endometriosis. The peritoneal fluid samples were collected during laparoscopic surgery from 30 women with and without endometriosis. Immunoregulatory cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ and TNF) and chemokines (CCL2, CCL5, CXCL8 and CXCL9) were evaluated in PF and culture supernatants generated by unstimulated and CD3/CD28/IL-2-stimulated CD4⁺ T cells cultured in the presence of PF. The effect of PF on the generation of Treg and Th17 cells in CD4⁺ T cell cultures, as well as the natural cytotoxic activity of peripheral blood mononuclear cells, was also investigated. Concentrations of IL-6, IL-10, CCL2, CXCL8 and CXCL9 were significantly upregulated in the PF from women with endometriosis when compared to control women, whereas concentrations of other cytokines and chemokines were unaffected. The culturing of unstimulated and CD3/CD28/IL-2-stimulated CD4⁺ T cells in the presence of endometriotic PF resulted in the downregulation of their IL-2, IFN-γ, IL-17A and TNF production as compared to culture medium alone. On the other side, endometriotic PF significantly stimulated the production of IL-4 and IL-10. Endometriotic PF also stimulated the release of CCL2 and CXCL8, whereas the production of CCL5 and CXCL9 was downregulated. Endometriotic PF stimulated the generation of Treg cells and had an inhibitory effect on the generation of Th17 cells in cultures of CD4⁺ T cells. It also inhibited the NK cell cytotoxic activity of the peripheral blood lymphocytes. These results strongly imply that the PF from patients with endometriosis has immunoregulatory/immunosuppressive activity and shifts the Th1/Th2 cytokine balance toward the Th2 response, which may account for deviation of local and systemic immune responses. However, a similar trend, albeit not a statistically significant one, was also observed in case of PF from women without endometriosis, thus suggesting that peritoneal milieu may in general display some immunoregulatory/immunosuppressive properties. It should be stressed, however, that our present observations were made on a relatively small number of PF samples and further studies are needed to reveal possible mechanism(s) responsible for this phenomenon.

Endometriosis is a common gynecological disorder characterized by the presence of endometrial-like tissue outside the uterus. The disease is associated with disturbed local and systemic immunity. It has been reported that the proportion of CD4⁺CD25^highFOXP3⁺ Treg cells may be significantly increased in the peritoneal fluid of patients with endometriosis. Therefore, the aim of our study was to investigate whether the proportions of Treg cells in the peritoneal cavity of patients with endometriosis are related to the chemotactic and stimulatory activity of the local peritoneal milieu. The peritoneal fluid was collected from 13 women with ovarian endometriosis and 12 control women without the disease. T cell populations were analyzed by flow cytometry, cytokines and chemokines were evaluated using the cytometric bead kit, and cell chemotaxis was studied by cell migration assay. We confirmed that the proportions of Treg cells are increased in the peritoneal fluid of women with endometriosis as compared to the control women. Endometriosis was also associated with elevated concentrations of IL-6, IL-10, and TGF-β1/2 as well as CCL20, CXCL8, CXCL9, and CXCL10. We did not reveal any changes in the proportion of peritoneal Th17 cells and concentrations of IL-17A. Peritoneal Treg cells positively correlated with concentrations of TGF-β, IL-10, and CCL20. Endometriotic peritoneal fluid stimulated chemotaxis of both CD4⁺ and Treg cells. This chemotactic activity positively correlated with concentrations of CCL20. CCL20 stimulated the migration of Treg cells, and the chemotactic activity of the endometriotic peritoneal fluid was inhibited by neutralizing anti-CCL20 antibodies. These results imply that increased proportions of the peritoneal Treg cells in women with endometriosis may result from attraction and activation by local chemokines and cytokines, especially CCL20 and TGF-β. Since Treg cells contribute to the immunopathogenesis of endometriosis, their chemotaxis and activation may be considered as a target for therapeutic intervention.

Introduction: Increased levels and activity of some matrix metalloproteinases (MMPs) are described in obesity-related vascular diseases. Factors that influence MMP blood concentration are still being investigated. This research aims to evaluate the concentration of most types of MMPs: collagenases (MMP-1, -3, -8, -13), matrilysin (MMP-7), gelatinase (MMP-9), and metalloelastase (MMP-12) in serum of women in reproductive age in relation with their body mass index (BMI), age, oestradiol, and progesterone concentrations. Material and methods: Blood samples were taken from 54 healthy reproductive-aged women with normal menstrual cycles. The weight and height of all women were measured, and body mass index (BMI) was calculated. Concentration of MMP-1, -3, -7, -8, -9, -12, and MMP-13 was evaluated using a Procarta Immunoassay Kit. Serum concentrations of oestradiol and progesterone were evaluated by immunochemiluminescence (32 in the proliferative and 20 in the secretory phase of menstrual cycle). The results of the study were statistically calculated using Pearson, Spearman, and Kruskal-Wallis tests. Results: Positive correlation between MMP-7, -8, -9, -12, and -13 levels and BMI was demonstrated. Significantly higher concentrations of MMPs were found especially in obese women compared to women with normal BMI. In healthy, regularly menstruating premenopausal women, MMP levels did not correlate with oestradiol and progesterone concentrations. Conclusions: The results suggest that body mass can influence MMP serum concentration in women with regular menstrual cycles. Introduction: Increased levels and activity of some matrix metalloproteinases (MMPs) are described in obesity-related vascular diseases. Factors that influence MMP blood concentration are still being investigated. This research aims to evaluate the concentration of most types of MMPs: collagenases (MMP-1, -3, -8, -13), matrilysin (MMP-7), gelatinase (MMP-9), and metalloelastase (MMP-12) in serum of women in reproductive age in relation with their body mass index (BMI), age, oestradiol, and progesterone concentrations. Material and methods: Blood samples were taken from 54 healthy reproductive-aged women with normal menstrual cycles. The weight and height of all women were measured, and body mass index (BMI) was calculated. Concentration of MMP-1, -3, -7, -8, -9, -12, and MMP-13 was evaluated using a Procarta Immunoassay Kit. Serum concentrations of oestradiol and progesterone were evaluated by immunochemiluminescence (32 in the proliferative and 20 in the secretory phase of menstrual cycle). The results of the study were statistically calculated using Pearson, Spearman, and Kruskal-Wallis tests. Results: Positive correlation between MMP-7, -8, -9, -12, and -13 levels and BMI was demonstrated. Significantly higher concentrations of MMPs were found especially in obese women compared to women with normal BMI. In healthy, regularly menstruating premenopausal women, MMP levels did not correlate with oestradiol and progesterone concentrations. Conclusions: The results suggest that body mass can influence MMP serum concentration in women with regular menstrual cycles.