Nicole Hacker

Osteocalcin levels on oral glucose load in women being investigated for polycystic ovary syndrome.

OBJECTIVE Osteocalcin (OC) might play a hormone-like role in energy metabolism and the regulatory circuit between the pancreas and osteoblasts. Effects of a 75-g oral glucose tolerance test (OGTT) on total OC, undercarboxylated (ucOC), and carboxylated osteocalcin (cOC) in insulin-resistant (IR) and noninsulin-resistant (nIR) premenopausal women was evaluated, and the relationships of changes in OC, ucOC, and cOC with area under the curve (AUC) insulin and the Matsuda index were examined. METHODS In this cross-sectional study, 105 premenopausal women underwent OGTT; 18 were IR (homeostatic model assessment of insulin resistance [HOMA-IR] > 2.6; (2 with type 2 diabetes, 2 with impaired glucose tolerance), and 87 were nIR (3 with impaired glucose tolerance). Changes in total OC, ucOC, and cOC were evaluated 60 and 120 minutes after glucose loading. RESULTS At baseline, IR subjects had significantly lower levels of total OC, cOC, and ucOC. In nIR women, total OC decreased by 19% from 18.0 ng/mL (14.5-24.7) at baseline to 14.6 ng/mL (10.9-17.8) after 120 minutes, ucOC decreased by 22% from 3.2 ng/mL (2.1-4.5) to 2.5 ng/mL (1.7-3.5), and cOC decreased by 26% from 14.9 ng/mL (12.1-20.4) to 11.1 ng/mL (9.0-14.5) (P < .001, respectively). No significant decreases were noted in IR subjects. The declines in OC and cOC predicted AUCinsulin (ΔOC: β = 0.301, P = .001; ΔcOC: β = 0.315, P < .001) and the Matsuda index (ΔOC: β = -0.235, P = .003; ΔcOC: β = -0.245, P = .002). CONCLUSIONS Glucose intake lowers levels of OC, ucOC, and cOC in nIR women, the extent of which predicts IR and insulin sensitivity in premenopausal women. OC parameters seem suppressed in IR women. There might be a differential osteoblast response to oral glucose in IR and nIR women, with OC reflecting this finding.

Osteocalcin is not a strong determinant of serum testosterone and sperm count in men from infertile couples.

Osteocalcin (OC) – released by osteoblasts and known as a marker of bone turnover – has been suggested to influence male fertility in murine models by enhancing testosterone production and sperm count. Results from clinical studies are scarce, however. The aim of this cross‐sectional study was to investigate the proposed association of OC, undercarboxylated osteocalcin (ucOC) or carboxylated osteocalcin (cOC) with testosterone and sperm count in a cohort of 159 young male adults from infertile couples. Semen analysis was performed. Testosterone, free testosterone, LH, OC and ucOC were measured in serum samples after an overnight fast. cOC and OC correlated weakly but significantly with testosterone (OC: r = 0.165, p = 0.040, cOC: r = 0.193, p = 0.017), but not after adjusting for age and body mass index (BMI) or waist–hip ratio (WHR). %ucOC (ucOC levels expressed as percentage of total OC) correlated inversely with LH (r = −0.184, p = 0.023) and remained significant after the same adjustment. No significant correlations were observed between OC, cOC, ucOC, %ucOC and sperm count, semen volume and number of vital spermatozoa. In binary logistic regression analyses, none of the parameters of OC were predictors of oligozoospermia after adjusting for age and BMI or WHR. The weak association between %ucOC and LH has marginal clinical importance because of the lack of associations of parameters of OC with testosterone and sperm count. The current data thus cannot support the notion that OC is associated with male fertility in young men from infertile couples.

Vasculature and bone: stages of atherosclerosis come along with changes in gene expression levels of calcification regulators

Calcification in the vasculature is one of the leading causes of cardiovascular diseases and mortality outcomes. The present knowledge about expression of calcification regulators in bone compared to vasculature is fragmentary. Therefore, the aim of our study was to investigate changes in the gene expression of calcification regulators (CR) in arterial vessels during different stages of atherosclerosis and to document potential corresponding changes in the bone. Atherosclerotic changes in the vessels were defined by three histological stages of atherosclerosis: (0) no changes, (1) intima thickening or (2) intima calcification. Bone tissue samples were subgrouped accordingly.

Changes of expression of regulators of calcification in different stages of atherosclerosis in vasculature and bone

Introduction and aim: Calcification is physiologically present in bone but also pathophysiologically in the vasculature, favouring cardiovascular diseases. Cardiovascular diseases are one of the most common causes of death within patients with chronic kidney disease and crucial for kidney transplantation (RTX) outcomes. The present knowledge about expression of calcification regulators in bone compared to vasculature is fragmentary. Our aim was to investigate these changes in the expression of calcification regulators (CR) during vascular calcification simultanously in bone and vasculature. Furthermore we tested the effect of systemic regulators of bone calcification in HEK293, HOS, EA.hy926 cells and HUVECs.