Characterization of peripheral T helper 17 (Th17) cells phenotype in postmenopausal women with estrogen insufficiency.

Over the past few years, Th17 cells is considered a key player in osteoporosis pathogenesis. Although extensively studied in murine models, comprehensive Th17 cell characterization in osteoporotic women is elusive. We thus aimed to examine peripheral Th17 cells frequency and phenotypes in healthy and osteoporotic women. Our results demonstrated that Th17 cells were primarily CD4+CD45RA-CCR7-HALDR+CCR6lowT-cells. Compared to Pre-N, Post-L showed increased proportion of Th17 with concomitant decrease in Th1 cells. The Th17 cells frequency in effector memory CD4+ T cells was significantly elevated in Post-N with a decrease of Th1 cells in effector memory subsets compared to Pre-N and Post-L. Both Post-N and Post-L had decreased frequency of dual positive Th1-Th17 cells and increased HLA-DR expression on Th17 cells compared to Pre-N. Thus, our study demonstrates increased Th17 cells frequency and reduced Th1 cells frequency with effector memory phenotype in postmenopausal women with estrogen insufficiency and correlates with aging process.

Association of OPG and RANKL gene polymorphisms with bone mineral density in Indian women.

Osteoprotegerin (OPG) and receptor activator of the NF-kB ligand (RANKL) are key players in bone remodelling. Reports show that OPG and RANKL gene polymorphisms are associated with osteoporosis and fracture risk. The aim of this study was to examine the influence of 5 single nucleotide polymorphisms (SNPs) in OPG and RANKL gene on bone mineral density (BMD) in Indian women. The study included 374 healthy Indian women. Kompetitive Allele Specific PCR (KASP) was used for genotyping. There was a significant difference in the BMD at spine between genotypes of OPG rs2073618 (CC: 0.988 ± 0.167 CG: 1.023 ± 0.17 GG: 1.053 ± 0.155; p = 0.039) which was lost upon adjustment for age and BMI (p = 0.087). Multiple linear regression revealed that genotypes of OPG rs2073618 (ß = 0.098; p = 0.027) and rs3102735 (ß = 0.092; p = 0.038) are predictors of BMD at spine in Indian women. We did not observe any association of SNPs in RANKL gene with BMD. Thus, SNPs rs2073618 and rs3102735 in OPG gene may influence BMD at spine in Indian women.

Increased frequency of Th17 cells and IL-17 levels are associated with low bone mineral density in postmenopausal women.

Osteoporosis is one of the chronic and often neglected bone diseases in aging postmenopausal women that affect the quality of life. Studies on ovariectomized mice models indicated the reciprocal role of Th17 cells and Treg cells in the aetiology of osteoporosis. While Th17 cells promote osteoclastogenesis, Treg cells exhibit anti-osteoclastogenic activity. This exploratory study aimed to determine the difference in the frequency of these T-cell subtypes in pre-and postmenopausal women and to examine their association with BMD. In our study, the frequency of Treg cells, analyzed by flow cytometry, did not differ between pre-and postmenopausal women. However, plasma levels of IL-10 along with IL-10+CD4+T cells were higher in post- compared to premenopausal women. The frequency of Th17 cells was higher in postmenopausal women irrespective of their BMD, however, only postmenopausal women with low BMD had elevated IL-17 levels and their T-scores were associated with Th17 frequency. Collectively, the results suggest that estrogen insufficiency in postmenopausal women may lead to increased Th17 cell frequency and elevated IL-17 levels which are associated with low BMD. This study highlights, Th17 cells and IL-17 as key players in the pathogenesis of osteoporosis and they can be the potential targets for immunotherapy in the treatment of osteoporosis.

Effect of Vitamin D Levels on Bone Remodeling in Healthy Women.

BACKGROUND: Vitamin D deficiency is prevalent among Indian women. Subclinical vitamin D deficiency is a significant risk factor for osteopenia and fractures. However, its effect on bone metabolism and bone mineral density (BMD) is still debatable. OBJECTIVES: This study aimed to determine relationships of the vitamin D status with bone turnover markers, carboxy-terminal telopeptide of type-I collagen (CTX), N-terminal propeptide of type I procollagen (PINP), and BMD in healthy Indian women. METHODS: In this cross-sectional study, we determined serum levels of 25-hydroxy vitamin D (25(OH)D), parathyroid hormone, serum CTX, and PINP using commercial ELISA kits in 310 healthy Indian women aged 25 - 65 years who underwent BMD measurements with DXA scan. RESULTS: The prevalence of vitamin D deficiency was 53.87% and vitamin D insufficiency 31.29%. A direct correlation of BMD with vitamin D levels was not observed. PINP negatively correlated with vitamin D in both premenopausal (Spearman's r = -0.169, P < 0.05) and postmenopausal (Spearman's r = -0.241, P < 0.05) women. However, CTX positively correlated with vitamin D in both premenopausal (Spearman's r = 0.228, P < 0.01) and postmenopausal (Spearman's r = 0.244, P < 0.05) women. CONCLUSIONS: Vitamin D deficiency is more prevalent in premenopausal women than in postmenopausal ones. Although vitamin D does not show any association with BMD, it affects bone remodeling, which is reflected by changes in the bone formation marker PINP and the bone resorption marker CTX.

Development of an in house ELISA for human intact osteocalcin and its utility in diagnosis and management of osteoporosis.

BACKGROUND: Serum Osteocalcin (OC) is a biomarker for evaluating bone turnover in humans. Commercial kits of OC in India are imported, hence the associated high cost prohibits their use in routine screening of osteoporosis. The present study describes the development, validation of human OC ELISA and establishes cut off values for its use in screening and management of women at risk for osteoporosis. METHODS: A sandwich OC ELISA was developed using immuno-reagents prepared indigenously and validated for analytical sensitivity, specificity, accuracy and compared with commercial kit using Bland-Altman method. The utility of OC assay was evaluated by ROC analysis. RESULTS: The new ELISA was sufficiently precise, accurate, matrix-free, sensitive and cost effective. The levels of OC were significantly different in women with osteopenia and osteoporosis (ANOVA, p < .0001) compared to women with normal BMD. ROC analysis demonstrated the cut off values of OC >11.9 ng/mL for osteopenia and > 14.9 ng/mL for osteoporosis. The OC levels had maximum AUC of 0.831 in osteopenia and 0.932 in osteoporosis. Further, OC levels showed significant changes within 3 months in women monitored on therapy. CONCLUSION: The developed OC ELISA has great potential to be used as a biomarker for routine screening and management of osteoporosis in Indian women.