Vitamin D, Its Receptor Gene Polymorphism and Breast Cancer

Vitamin D is synthesized within skin followed by the peripheral maturation in liver and kidneys. Vitamin D is most essential secosteroid produced its systemic functions via complex with steroid/thyroid nuclear receptor called vitamin D receptor (VDR). The binding of the vitamin D3 to VDR causes conformational changes that permit VDR-RXR heterodimer formation and VDR/ SRC-1 (transcriptional co-activator proteins) interactions. Functional expression and nuclear activation of VDR is necessary to produce its effects upon binding with vitamin D response element (VDRE) on target gene where it causes transcriptional activation resulting in the prevention of breast cancer by inhibiting proliferation, impeding differentiation and stimulating pro-apoptosis. Season, latitude, pigmentation of skin, aging, sunscreen use, obesity, and smoking all affect the production of vitamin D. In case of vitamin D deficiency or VDR gene polymorphisms, vitamin D responses are altered and probably are involved in the risk of breast cancer. Since many epidemiological, observational and interventional studies have been done to illustrate the role of vitamin D and its receptor gene polymorphism in breast cancer development but controversial findings have been observed. Therefore, the role of vitamin D and its receptor gene polymorphisms in development of breast cancer are still a matter of discussion

Association of oxidative stress with female infertility - a case control study

Objective: To compare stress markers and reproductive hormones in fertile and infertile females, and to relate the markers with age, duration and cause of infertility, and body mass index..Methods: The case-control study was conducted at Aga Khan University Hospital, Karachi, from March 2017 to February 2018. Females aged 16-50 years regardless of ethnic background were recruited from the Australian Concept Infertility Medical Centre, Karachi, and were equally divided into infertile cases group A, and fertile controls group B. Serum follicular stimulating hormone, luteinizing hormone, estradiol, glutathione reductase and cortisol were measured using enzyme-linked innmunosorbent assay. SPSS 19 was used for statistical analysis..Results: There were 328 female subjects divided into two equal groups of 164(50%). Serum luteinizing hormone and cortisol was higher in the group A than in group B (p\u3c0.001). Serum glutathione reductase was low in group A compared to group B (p\u3c0.001). Duration of infertility, serum levels of glutathione reductase and cortisol were also significantly different among infertile females when distributed on the basis of cause of infertility (p\u3c0.05). Serum cortisol had negative correlation with glutathione reductase (p\u3c0.001). Age and body mass index had a positive correlation with serum cortisol (p=0.035; p=0.63), while there was a negative correlation with glutathione reductase (p = -0.732)..Conclusions: Prolonged duration of infertility, age of females and body mass index enhanced the production of stress hormones and decreased antioxidant activity which augmented the risk of infertility

KCNQ1 rs2237895 polymorphism is associated with Gestational Diabetes in Pakistani Women

Background and Objective: Genetic studies on gestational diabetes (GDM) are relatively scarce; moreover, limited data is available for KCNQ1 polymorphism in Pakistani pregnant women. We aimed to determine the frequency of KCNQ1 rs2237895 in GDM and normal pregnant controls and its association with GDM-related phenotypes.Methods: A total of 637 pregnant females (429 controls and 208 cases) in their second trimester were classified according to the International Association of the Diabetes and Pregnancy Study criteria in this study. Their blood samples were genotyped for KCNQ1 SNP rs2237895 using PCR-RFLP method and sequencing. Fasting and two hour-post glucose load blood levels, serum HbA1c, insulin, and anthropometric assessment was performed.: Pearson\u27s Chi Square test, Mann- Whitney U test, and regression analyses were performed. A p-value of \u3c 0.05 was considered significant.Results: The variant genotyped was in Hardy-Weinberg equilibrium (p \u3e 0.05). The rs2237895 showed an association with GDM (OR 2.281; 1.388-3.746: p \u3c 0.001) and remained significant after multiple adjustments for age and body mass index (OR 2.068; 1.430-2.997: p=0.005). The C allele showed positive association with insulin level, and HOMA-IR in study subjects.Conclusions: This study identifies that KCNQ1 rs2237895 polymorphisms might be associated with risk of GDM in Pakistani population and that it is related to higher glucose levels and insulin resistance. Further large scale studies are required to consolidate on the functional aspect of this polymorphism

Interplay between oxidative stress, SIRT1, reproductive and metabolic functions

Silent information Regulators (SIRT1) gene stimulates antioxidants\u27 expression, repairs cells damaged by oxidative stress (OS), and prevents the cells\u27 dysfunction. In particular, the role of different Sirtuins, particularly SIRT1 in reproduction, has been widely studied over the past decade. Decreased SIRT 1 causes mitochondrial dysfunction by increasing Reactive Oxygen Species (ROS), lipid peroxidation, and DNA damage in both male and female gametes (Sperms and Oocytes), leading to infertility. In the female reproductive system, SIRT1 regulates proliferation and apoptosis in granulosa cells (GCs), and its down-regulation is associated with a reduced ovarian reserve. SIRT1 also modulates the stress response to OS in GCs by targeting a transcription factor vital for ovarian functions and maintenance. ROS-mediated damage to spermatozoa\u27s motility and morphology is responsible for 30-80% of men\u27s infertility cases. High levels of ROS can cause damage to deoxyribo nucleic acid (DNA) in the nucleus and mitochondria, lipid peroxidation, apoptosis, inactivation of enzymes, and oxidation of proteins in spermatozoa. SIRT 1 is a cardioprotective molecule that prevents atherosclerosis by modulating various mechanisms such as endothelial injury due to impaired nitric oxide (NO) production, inflammation, OS, and regulation of autophagy. SIRT 1 is abundantly expressed in tubular cells and podocytes. It is also found to be highly expressed in aquaporin 2 positive cells in the distal nephron suggesting its involvement in sodium and water handling. SIRT1 improves insulin resistance by reducing OS and regulating mitochondrial biogenesis and function. It also decreases adiposity and lipogenesis and increases fatty acid oxidation. So, its involvement in the multiple pathways ensures its unique role in reproductive and metabolic derangement mechanisms

Gestational diabetes mellitus and the predisposing factors

Objective: To evaluate the occurrence of gestational diabetes mellitus and its association with demographic and anthropometric variables in pregnant women.Methods: This cross-sectional study was conducted at the Aga Khan University Hospital, Abbasi Shaheed Hospital and Memon Hospital in Karachi, from February 2014 to December 2015, and comprised pregnant women who were screened by 75-g 2-hour oral glucose tolerance test, (24-28 weeks of gestation) and classified as per the criteria of the International Association of Diabetes and Pregnancy Study Group. Weight, body mass index and serum glycated haemoglobin levels were measured. Women with pre-gestational diabetes were excluded. SPSS 21 was used for data analysis.Results: Of the 1,210 participants, 208(17.2%) had gestational diabetes, while 1,002(82.8%) did not have the condition. Gestational diabetes was associated with advancing age, deranged glycated haemoglobin, elevated body mass index at booking (p0.05).Conclusions: Pre-existing adiposity and presence of strong family history rendered a considerable number of pregnant women to suffer from gestational diabetes

Association of promoter region A-1012G polymorphism (rs4516035) of vitamin-D receptor gene with coronary artery disease

Objective: To investigate the correlation of Adenine-1012-Guanine (rs4516035) promoter region polymorphism of vitamin-D receptor gene with serum levels of omentin-1, vitamin-D and vitamin-D receptor protein in patients with coronary artery disease. Method: The case-control study was conducted January to June 2020 at the cardiac unit of Civil hospital Karachi (CHK), and comprised coronary artery disease patients and controls. The tetra-primer amplification refractory mutation system polymerase chain reaction method was used to genotype Adenine-1210Guanine polymorphism in the vitamin D receptor gene.  Serum levels of omentin-1, vitamin-D, and vitamin-D receptor protein were measured in both the groups using an enzyme-linked immunosorbent assay. Data was analysed using SPSS 17. Results: Of the 1,000 subjects, there were 500(50%) cases; males 306(61.2%) and 194(38.8%) females with overall mean age of 51.08±9.55 years. The remaining 500(50%) were controls; 290(58%) males and 210(42%) females with overall mean age of 50.9±10.78 years. The mutant Guanine allele was more prevalent in controls 261(52.2%), and had a non-significant correlation with coronary artery disease (p=0.45).  Among the cases, the wild Adenine-Adenine genotype had a higher prevalence 402(80.4%) and had a significant correlation with coronary artery disease (p<0.001). The heterozygous genotype Adenine-Guanine was significantly more predominant among the controls 346(69.2%) compared to the cases 66(13.2) (p=0.002). Conclusion: Adenine-1012-Guanine polymorphism in the vitamin-D receptor gene was found to be a protective polymorphism for coronary artery disease in the recessive model. Key Words: Coronary artery disease, Omentin-1, Vitamin-D, Vitamin-D receptor

An interplay of progesterone, leukemia inhibitor factor and interleukin-6 in the window of implantation; impact on fertility

Background: The process of implantation is crucial for the initiation of conception and hence fertility. In addition to a number of factors, it is regulated by a cross talk of gonadotrophins [Luteinizing Hormone (LH), Follicle Stimulatory Hormone (FSH)], ovarian steroids [Estrogen (Et), Progesterone (Pt)] and cytokines [Leukemia inhibitory factor (LIF) and Interleukin 6 (IL6)]. These biomarkers are chief players of implantation.Objective: We aimed to explore the role of gonadotrophins (LH, FSH, LH/FSH ratio), ovarian steroids (Et, Pt) and cytokines (LIF, IL6) in the implantation process. This aim was achieved by comparing these hormones and cytokines in the fertile and infertile groups [Polycystic ovaries (PCOs), endometriosis, unexplained infertility (Uex-IF)] and finding their association in all study groups.Methods: A case control study conducted from October 2020-March 2023. A total of 135 infertile women (with PCOs, Uex-IF, and endometriosis) and 177 fertile women (matched for age and BMI) were selected. Levels of \u27Et\u27, \u27Pt\u27, \u27LIF\u27 and, \u27IL6\u27 were estimated using Enzyme Linked Immunosorbent Assay (ELISA). LH and FSH values were obtained from hospital desk records. The Independent Student\u27st-test was used to compare fertile and infertile groups. One-way ANOVA test was used to compare more than two groups, and Pearson\u27s chi-square (χ2) test was employed to compare percentages of variables. Pearson correlation analysis was performed to assess the associations and correlations. A p value \u3c 0.05 was considered statistically significant.Results: Significantly higher levels of LIF and IL6 were observed in fertile women compared to infertile women. Pt levels were significantly greater in the fertile group than in the infertile group. The FSH/LH ratio was significantly higher in the fertile group. Among infertile women, PCOs (71%) and Uex-IF (91%) exhibited lower Pt levels than the fertile controls (p \u3c 0.01), but these levels remained within the reference range (RR). Among the fertile group (81%), levels of LIF within the RR were significantly higher compared to those with Uex-IF (49%) and females with endometriosis (37%). Moreover, the highest number of participants (57%) with Uex-IF exhibited IL6 levels significantly below the RR in comparison to the fertile group and infertile groups (PCOS and endometriosis). However, lower levels of IL6 were observed in women with Uex-IF. In the control group, LIF exhibited a significant positive correlation with IL6 (r = 0.370), Pt (r = 0.496), Et (r = 0.403), and LH (r = 0.428). Among women with PCOs, LIF showed a significant positive correlation with IL6 (r = 0.443), Pt (r = 0.607), and LH (r = 0.472). In cases of Uex-IF, LIF demonstrated a significant positive correlation with IL6 (r = 0.727). Females with endometriosis displayed a significant positive correlation between LIF and IL6 (r = 0.535) as well as Pt (r = 0.605). In fertile women, a positive correlation was observed between LH and IL6 (r = 0.197, p = 0.009), LIF (r = 0.428, p = 0.000), Pt (r = 0.238, p = 0.001), and Et (r = 0.356, p = 0.000). Furthermore, a positive correlation was found between LH and LIF (r = 0.472, p = 0.000) in women with PCOs.Conclusion: Elevated levels of Pt were found to increase the production of LIF in fertile females. However, infertile females with PCOs and Uex-IF exhibited deficient levels of Pt, supporting its role as a biomarker for successful implantation in infertile women. These females showed decreased levels of gonadotropins as well as reduced LH/FSH ratio and diminished secretion of receptivity marker LIF, in addition to reduced Pt secretion. This suggests that reduced gonadotropin levels contribute to a lower LH/FSH ratio, resulting in decreased Pt secretion and ultimately leading to low levels of LIF, thereby causing impaired implantation in women with PCOs and Uex-IF. The exploration of low levels of LIF in patients with endometriosis requires further investigation. The significantly low levels of IL6 in the Uex-IF group elucidate the role of this cytokine in association with decreased Pt and LIF synthesis within this group