Osteocalcin of maternal and embryonic origins synergize to establish homeostasis in offspring.

Many physiological osteocalcin-regulated functions are affected in adult offspring of mothers experiencing unhealthy pregnancy. Furthermore, osteocalcin signaling during gestation influences cognition and adrenal steroidogenesis in adult mice. Together these observations suggest that osteocalcin may broadly function during pregnancy to determine organismal homeostasis in adult mammals. To test this hypothesis, we analyzed in unchallenged wildtype and Osteocalcin-deficient, newborn and adult mice of various genotypes and origin maintained on different genetic backgrounds, the functions of osteocalcin in the pancreas, liver and testes and their molecular underpinnings. This analysis revealed that providing mothers are Osteocalcin-deficient, Osteocalcin haploinsufficiency in embryos hampers insulin secretion, liver gluconeogenesis, glucose homeostasis, testes steroidogenesis in adult offspring; inhibits cell proliferation in developing pancreatic islets and testes; and disrupts distinct programs of gene expression in these organs and in the brain. This study indicates that osteocalcin exerts dominant functions in most organs it influences. Furthermore, through their synergistic regulation of multiple physiological functions, osteocalcin of maternal and embryonic origins contributes to the establishment and maintenance of organismal homeostasis in newborn and adult offspring.

Osteocalcin: A Multifaceted Bone-Derived Hormone.

Together, loss- and gain-of-function experiments have identified the bone-derived secreted molecule osteocalcin as a hormone with a broad reach in rodents and primates. Following its binding to one of three receptors, osteocalcin exerts a profound influence on various aspects of energy metabolism as well as steroidogenesis, neurotransmitter biosynthesis and thereby male fertility, electrolyte homeostasis, cognition, the acute stress response, and exercise capacity. Although this review focuses mostly on the regulation of energy metabolism by osteocalcin, it also touches on its other functions. Lastly, it proposes what could be a common theme between the functions of osteocalcin and between these functions and the structural functions of bone.

Reference limits for osteocalcin in infancy and early childhood: A longitudinal birth cohort study.

OBJECTIVE: The longitudinal variations in serum levels of the hormone osteocalcin is largely unknown during infancy and early childhood. Our aim was to establish reference limits for total serum osteocalcin during specific time points from birth until 5 years of age and present those in the context of sex, breastfeeding practices and gestational age (GA). DESIGN: Blood samples from 551 Swedish children were analysed at birth, 4, 12, 36 and 60 months of age. Total serum osteocalcin was measured using the IDS-iSYS N-MID Osteocalcin assay technique. Information about the mother, birth, anthropometrics and a food diary were collected. RESULTS: Sex-specific and age-specific reference limits were established for the five time points. The median osteocalcin levels over time were 40.8, 90.0, 67.8, 62.2 and 80.9 µg/L for boys and 38.1, 95.5, 78.3, 73.9 and 92.6 µg/L for girls. Lower GA was associated to higher osteocalcin at birth, and ongoing breastfeeding was associated to higher osteocalcin levels. CONCLUSION: Osteocalcin followed a wavelike pattern with low levels in the umbilical cord and a postnatal peak during the first year which then declined and rose again by the age of five. Knowledge of this wavelike pattern and association to factors as sex, breastfeeding and GA may help clinicians to interpret individual osteocalcin levels and guide in future research.

Effect of vitamin D supplementation or fortification on bone turnover markers in women: a systematic review and meta-analysis.

Vitamin D is a vital indicator of musculoskeletal health, as it plays an important role through the regulation of bone and mineral metabolism. This meta-analysis was performed to investigate the effects of vitamin D supplementation/fortification on bone turnover markers in women. All human randomised clinical trials reported changes in bone resorption markers (serum C-terminal telopeptide of type-I collagen (sCTX) and urinary type I collagen cross-linked N-telopeptide (uNTX)) or bone formation factors (osteocalcin (OC), bone alkaline phosphatase (BALP) and procollagen type-1 intact N-terminal propeptide (P1NP)) following vitamin D administration in women (aged ≥ 18 years) were considered. Mean differences (MD) and their respective 95 % CI were calculated based on fixed or random effects models according to the heterogeneity status. Subgroup analyses, meta-regression models, sensitivity analysis, risk of bias, publication bias and the quality of the included studies were also evaluated. We found that vitamin D supplementation had considerable effect on sCTX (MD: -0·038, n 22) and OC (MD: -0·610, n 24) with high heterogeneity and uNTX (MD: -8·188, n 6) without heterogeneity. Our results showed that age, sample size, dose, duration, baseline vitamin D level, study region and quality of studies might be sources of heterogeneity in this meta-analysis. Subgroup analysis also revealed significant reductions in P1NP level in dose less than 600 µg/d and larger study sample size (>100 participants). Moreover, no significant change was found in BALP level. Vitamin D supplementation/fortification significantly reduced bone resorption markers in women. However, results were inconsistent for bone formation markers.

Identification of novel risk factors for postoperative severe hypocalcemia in patients with primary hyperparathyroidism undergoing parathyroidectomy: a case control study.

BACKGROUND: Patients with primary hyperparathyroidism (PHPT) are at risk for severe hypocalcemia (SH) following parathyroidectomy (PTX), but limited data exist on the predictors of SH. We aimed to identify risk factors for early postoperative SH after PTX in patients with PHPT and to evaluate the predictive value of clinical parameters. METHODS: A retrospective review of patients with PHPT who underwent PTX between January 2010 and December 2022 was performed. A total of 46 patients were included in the study, with 15 (32.6%) experiencing postoperative SH, 19 (41.3%) having calculi in the ureter or kidney, and 37 (80.4%) having osteoporosis. Patients were divided into SH and non-SH groups based on postoperative serum calcium levels. Preoperative biochemical indicators, bone turnover markers, and renal function parameters were analyzed and correlated with postoperative SH. RESULTS: Statistically significant (P < 0.05) differences were found in preoperative serum calcium (serum Ca), intact parathyroid hormone, serum phosphorus (serum P), serum Ca/P, percentage decrease of serum Ca, total procollagen type 1 intact N-terminal propeptide, osteocalcin (OC), and alkaline phosphatase levels between the two groups. Multivariate analysis showed that serum P (odds ratio [OR] = 0.989; 95% confidence interval [95% CI] = 0.981-0.996; P = 0.003), serum Ca (OR = 0.007; 95% CI = 0.001-0.415; P = 0.017), serum Ca/P (OR = 0.135; 95% CI = 0.019-0.947; P = 0.044) and OC levels (OR = 1.012; 95% CI = 1.001-1.024; P = 0.036) were predictors of early postoperative SH. The receiver operating characteristic curve analysis revealed that serum P (area under the curve [AUC] = 0.859, P < 0.001), serum Ca/P (AUC = 0.735, P = 0.010) and OC (AUC = 0.729, P = 0.013) had high sensitivity and specificity. CONCLUSION: Preoperative serum P, serum Ca/P and osteocalcin levels may identify patients with PHPT at risk for early postoperative SH after PTX.

Adult alcohol drinking and emotional tone are mediated by neutral sphingomyelinase during development in males.

Alcohol use, abuse, and addiction, and resulting health hazards are highly sex-dependent with unknown mechanisms. Previously, strong links between the SMPD3 gene and its coded protein neutral sphingomyelinase 2 (NSM) and alcohol abuse, emotional behavior, and bone defects were discovered and multiple mechanisms were identified for females. Here we report strong sex-dimorphisms for central, but not for peripheral mechanisms of NSM action in mouse models. Reduced NSM activity resulted in enhanced alcohol consumption in males, but delayed conditioned rewarding effects. It enhanced the acute dopamine response to alcohol, but decreased monoaminergic systems adaptations to chronic alcohol. Reduced NSM activity increased depression- and anxiety-like behavior, but was not involved in alcohol use for the self-management of the emotional state. Constitutively reduced NSM activity impaired structural development in the brain and enhanced lipidomic sensitivity to chronic alcohol. While the central effects were mostly opposite to NSM function in females, similar roles in bone-mediated osteocalcin release and its effects on alcohol drinking and emotional behavior were observed. These findings support the view that the NSM and multiple downstream mechanism may be a source of the sex-differences in alcohol use and emotional behavior.

Total osteocalcin levels are independently associated with worse testicular function and a higher degree of hypothalamic-pituitary-gonadal axis activation in Klinefelter syndrome.

PURPOSE: The role of osteocalcin (OCN) in pubertal development, male hypogonadism, and the effect of testosterone (Te) replacement therapy (TRT) remains unclear. We aimed to investigate the total OCN (tOCN) concentrations in male patients with Klinefelter syndrome (KS), a model of adult hypergonadotropic hypogonadism. METHODS: This retrospective longitudinal study investigated 254 male patients with KS (47,XXY) between 2007 and 2021 at an academic referral center, categorized as (1) prepubertal, (2) pubertal, and (3) adults. All prepubertal patients were Te-naïve. Adult patients were subcategorized as (1) eugonadal, (2) hypogonadal, and (3) receiving TRT. We also analyzed 18 adult patients with available tOCN levels before and 3 months after TRT commencement. RESULTS: The tOCN levels varied throughout the lifespan according to pubertal status, were highest in eugonadal and significantly lower in TRT subjects, correlated with both LH (p = 0.017) and FSH levels (p = 0.004) in adults, and significantly declined after 3 months of TRT (p = 0.006) in the adult KS cohort. HPG-axis hormones levels demonstrated no correlation in prepubertal boys. Adjustment for age and body mass index confirmed previous results and revealed significant inverse correlations with total Te (p = 0.004), calculated free Te (p = 0.016), the Te/LH (p = 0.010), and calculated free Te/LH ratios (p = 0.031). CONCLUSION: In KS, a model of male hypergonadotropic hypogonadism, tOCN levels were not associated with gonadal function during normal prepuberty and pubertal development but were associated with worse testicular function and a higher degree of HPG stimulation in adults. TRT acutely reduced tOCN levels in adults.

Final irrigation with bioglass solution in regenerative endodontic procedure induces tissue formation inside the root canals, collagen maturation, proliferation cell and presence of osteocalcin.

AIM: To evaluate the influence of an experimental solution of cobalt-doped F18 bioactive glass (F18Co) on tissue repair following regenerative endodontic procedure (REP) in rat molars. METHODOLOGY: The F18Co solution was prepared at a ratio of 1:5 F18Co powder to distilled water. The right or left upper first molars of 12 Wistar rats were used, where the pulps were exposed, removed, and irrigated with 2.5% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA) (5 min each). Subsequently, the molars were divided into two groups (n = 6): REP-SS and REP-F18Co, where they received a final irrigation (5 min) with saline solution (SS) or F18Co solution, respectively. Then, intracanal bleeding was induced, and the tooth was sealed. Untreated molars were used as controls (n = 3). At 21 days, the rats were euthanized, and the specimens were processed for analysis of mineralized tissue and soft tissue formation inside the root canal using haematoxylin-eosin. The presence and maturation of collagen were evaluated by Masson's trichrome and picrosirius red staining. Immunolabelling analyses of proliferating cell nuclear antigen (PCNA) and osteocalcin (OCN) were performed. The data were submitted to the Mann-Whitney U-test (p < .05). RESULTS: There was a similar formation of mineralized tissue in thickness and length in REP-SS and REP-F18Co groups (p > .05). Regarding the presence of newly formed soft tissue, most specimens of the REP-F18Co had tissue formation up to the cervical third of the canal, whilst the REP-SS specimens showed formation up to the middle third (p < .05), and there was higher maturation of collagen in REP-F18Co (p < .05). The number of PCNA-positive cells found in the apical third of the root canal was significantly higher in the F18Co group, as well as the OCN immunolabelling, which was severe in most specimens of REP-F18Co, and low in most specimens of REP-SS. CONCLUSION: The final irrigation with F18Co bioactive glass solution in REP did not influence mineralized tissue formation but induced soft tissue formation inside the root canals, with higher collagen maturation, and an increase in PCNA-positive cells and OCN immunolabelling.

Targeting the Role of PRME in Regulating Bone Remodelling During Postmenopausal Osteoporosis.

Kariavattom Campus Postmenopausal osteoporosis (PMO) is an old age disorder associated with estrogen deficiency, which reduces bone mass and makes bones more prone to fracture. The present study was proposed to evaluate the invivo osteogenic efficiency of Pterospermum rubiginosum methanolic bark extract (PRME) in the PMO model. Molecular docking studies on transcription factor NFATC1 showed excellent interactions with phytochemical ligands with the lowest binding energies. Female Sprague Dawley (SD) rats (n=24) were divided into four groups, (n=6 each) sham control (Group I) and osteoporotic control (Group II) groups treated with saline, PRME (50 mg/kg/day) and alendronate (10 mg/kg/day) treated with Group III and Group IV (n=6) respectively. The serum tartrate-resistant acid phosphatase 5b and cathepsin-K also exhibited a significant rise after PRME treatment 12.33±2.30 mU/ml and 427.68±46.97 pg/ml, respectively. DEXA results exhibited a remarkable increase in total bone mineral content and density values in PRME-treated animals (0.175±0.002 g/cm2) and (7.95±0.23 g) when compared to osteoporotic control (0.163±0.004 g/cm2) and (6.83±0.34 g). Long-term toxicity study revealed that PRME is non-toxic, up to 100 mg/kg bodyweight for 6 months. Our findings suggest PRME protects osteoporotic SD rats from PMO damage resulting from estrogen deficiency by regulating bone remodelling markers and upregulating BMD indices.

Extrahepatic Vitamin K-Dependent Gla-Proteins-Potential Cardiometabolic Biomarkers.

One mechanism to regulate pathological vascular calcification (VC) is its active inhibition. Loss or inactivation of endogenic inhibitors is a major inductor of VC. Such inhibitors are proteins rich in gamma-glutamyl residues (Gla-proteins), whose function strongly depends on vitamin K. The current narrative review is focused on discussing the role of extrahepatic vitamin K-dependent Gla-proteins (osteocalcin, OC; matrix Gla-protein, MGP; Gla-rich protein, GRP) in cardio-vascular pathology. Gla-proteins possess several functionally active forms whose role in the pathogenesis of VC is still unclear. It is assumed that low circulating non-phosphorylated MGP is an indicator of active calcification and could be a novel biomarker of prevalent VC. High circulating completely inactive MGP is proposed as a novel risk factor for cardio-vascular events, disease progression, mortality, and vitamin K deficiency. The ratio between uncarboxylated (ucOC) and carboxylated (cOC) OC is considered as an indicator of vitamin K status indirectly reflecting arterial calcium. Despite the evidence that OC is an important energy metabolic regulator, its role on global cardio-vascular risk remains unclear. GRP acts as a molecular mediator between inflammation and calcification and may emerge as a novel biomarker playing a key role in these processes. Gla-proteins benefit clinical practice as inhibitors of VC, modifiable by dietary factors.

Osteocalcin: A Potential Marker of Peripheral Arterial Stiffness in Hypertensive Patients.

Background and Objectives: Brachial-ankle pulse wave velocity (baPWV) is an established independent risk factor for cardiovascular events, cardiovascular mortality, and all-cause mortality. Osteocalcin (OC) is recognized to be associated with vascular function. The present study assessed the correlation between serum OC levels and peripheral arterial stiffness (PAS) measured through baPWV in hypertensive patients. Materials and Methods: Fasting blood samples were collected from 120 hypertensive participants. The serum total OC levels were measured using a commercial enzyme-linked immunosorbent assay kit, whereas the baPWV device was used to detect PAS. The PAS group had left or right baPWV > 18.0 m/s. Results: Among the hypertensive patients, 24 (20.0%) were classified into the PAS group. The PAS group exhibited a significantly older age (p = 0.011), higher prevalence of diabetes (p = 0.010), systolic blood pressure (p = 0.019), levels of serum fasting glucose (p = 0.003), blood urea nitrogen (p = 0.024), creatinine (p = 0.004), C-reactive protein (p = 0.007), OC (p = 0.002), and lower estimated glomerular filtration rate (p = 0.004) than the non-PAS group. Age (odds ratio [OR]: 1.076, 95% CI: 1.004-1.153, p = 0.037) and serum OC level (OR: 1.797, 95% confidence interval (CI): 1.077-3.000, p = 0.025) were independent factors linked to PAS in hypertensive patients in the multivariate logistic regression analysis. Conclusions: Serum OC levels and older age are positively associated with PAS in hypertensive patients.

Undercarboxylated osteocalcin and ibandronate combination ameliorates hindlimb immobilization-induced muscle wasting.

Immobilization leads to muscle wasting and insulin resistance, particularly during ageing. It has been suggested that undercarboxylated osteocalcin (ucOC) improves muscle mass and glucose metabolism. Bisphosphonates, an anti-osteoporosis treatment, might protect muscle wasting independent of ucOC. We hypothesize that the combination of ucOC and ibandronate (IBN) treatments has superior protective effects against immobilization-induced muscle wasting and insulin resistance than either treatment alone. C57BL/6J mice were hindlimb-immobilized for two weeks, with injections of vehicle, ucOC (90 ng/g daily) and/or IBN (2 µg/g weekly). Insulin/oral glucose tolerance tests (ITT/OGTT) were performed. Immediately after immobilization, muscles (extensor digitorum longus (EDL), soleus, tibialis anterior, gastrocnemius and quadriceps) were isolated and measured for muscle mass. Insulin-stimulated glucose uptake (EDL and soleus) was examined. Phosphorylation/expression of proteins in anabolic/catabolic pathways were examined in quadriceps. Primary human myotubes derived from older adult muscle biopsies were treated with ucOC and/or IBN, then signalling proteins were analysed. Combined treatment, but not individual treatments, significantly increased the muscle weight/body weight ratio in immobilized soleus (31.7%; P = 0.013) and quadriceps (20.0%; P = 0.0008) muscles, concomitant with elevated p-Akt (S473)/Akt ratio (P = 0.0047). Combined treatment also enhanced whole-body glucose tolerance (16.6%; P = 0.0011). In human myotubes, combined treatment stimulated greater activation of ERK1/2 (P = 0.0067 and 0.0072) and mTOR (P = 0.036), and led to a lesser expression of Fbx32 (P = 0.049) and MuRF1 (P = 0.048) than individual treatments. These findings suggest a potential therapeutic role for the ucOC and bisphosphonates combination in protecting against muscle wasting induced by immobilization and ageing. KEY POINTS: It has been suggested that undercarboxylated osteocalcin (ucOC) improves muscle mass and glucose metabolism. Bisphosphonates, an anti-osteoporosis treatment, might protect against muscle wasting independent of ucOC. The combination treatment of ucOC and ibandronate was shown to exert a greater therapeutic effect against immobilization-induced muscle wasting, and led to greater activation of anabolic pathway and less expression of catabolic signalling proteins in myotubes derived from older adults, compared with individual treatments. The combination treatment was found to improve whole-body glucose tolerance. Our findings suggest a potential therapeutic role for the ucOC and bisphosphonates combination in protecting against muscle wasting induced by immobilization and ageing.

Epithelial-like transport of mineral distinguishes bone formation from other connective tissues.

We review unique properties of bone formation including current understanding of mechanisms of bone mineral transport. We focus on formation only; mechanism of bone degradation is a separate topic not considered. Bone matrix is compared to other connective tissues composed mainly of the same proteins, but without the specialized mechanism for continuous transport and deposition of mineral. Indeed other connective tissues add mechanisms to prevent mineral formation. We start with the epithelial-like surfaces that mediate transport of phosphate to be incorporated into hydroxyapatite in bone, or in its ancestral tissue, the tooth. These include several phosphate producing or phosphate transport-related proteins with special expression in large quantities in bone, particularly in the bone-surface osteoblasts. In all connective tissues including bone, the proteins that constitute the protein matrix are mainly type I collagen and γ-carboxylate-containing small proteins in similar molar quantities to collagen. Specialized proteins that regulate connective tissue structure and formation are surprisingly similar in mineralized and non-mineralized tissues. While serum calcium and phosphate are adequate to precipitate mineral, specialized mechanisms normally prevent mineral formation except in bone, where continuous transport and deposition of mineral occurs.

Inhibition of miR-101-3p prevents human aortic valve interstitial cell calcification through regulation of CDH11/SOX9 expression.

BACKGROUND: Calcific aortic valve disease (CAVD) is the second leading cause of adult heart diseases. The purpose of this study is to investigate whether miR-101-3p plays a role in the human aortic valve interstitial cells (HAVICs) calcification and the underlying mechanisms. METHODS: Small RNA deep sequencing and qPCR analysis were used to determine changes in microRNA expression in calcified human aortic valves. RESULTS: The data showed that miR-101-3p levels were increased in the calcified human aortic valves. Using cultured primary HAVICs, we demonstrated that the miR-101-3p mimic promoted calcification and upregulated the osteogenesis pathway, while anti-miR-101-3p inhibited osteogenic differentiation and prevented calcification in HAVICs treated with the osteogenic conditioned medium. Mechanistically, miR-101-3p directly targeted cadherin-11 (CDH11) and Sry-related high-mobility-group box 9 (SOX9), key factors in the regulation of chondrogenesis and osteogenesis. Both CDH11 and SOX9 expressions were downregulated in the calcified human HAVICs. Inhibition of miR-101-3p restored expression of CDH11, SOX9 and ASPN and prevented osteogenesis in HAVICs under the calcific condition. CONCLUSION: miR-101-3p plays an important role in HAVIC calcification through regulation of CDH11/SOX9 expression. The finding is important as it reveals that miR-1013p may be a potential therapeutic target for calcific aortic valve disease.

Impact of vitamin D supplementation on markers of bone turnover: Systematic review and meta-analysis of randomised controlled trials.

AIM: The effects of vitamin D administration on bone turnover markers (BTMs) in adults are controversial. Thus, we carried out a meta-analysis of available randomised controlled trials (RCTs) to examine the impact of vitamin D supplementation on BTMs. METHODS: To identify relevant RCTs, we searched the PubMed/MEDLINE, Web of Science, Scopus, Cochrane Library and Embase databases for manuscripts published up to July 2022. The present study was conducted in agreement with the PRISMA guidelines. Weighed mean difference (WMD) and 95% confidence intervals (CI) were used to calculate the magnitude of the effect of the intervention. RESULTS: A total of 42 RCTs were included in the meta-analysis. The age of the participants enrolled in the RCTs ranged from 19.4 to 84 years. The pooled results depicted a decrease in deoxypyridinoline (DPD) concentrations (WMD: -1.58 nmol/mmol, 95% CI: -2.55, -.61, p = .001) following vitamin D supplementation. In addition, subgroup analyses demonstrated that vitamin D administration notably reduced procollagen type I N-terminal propeptide (PINP) levels in individuals aged >50 years and led to a pronounced decrease in alkaline phosphatase (ALP) values when the intervention lasted >12 weeks. No significant effect was observed on other BTMs, for example, collagen type 1 cross-linked C-telopeptide (CTX) and osteocalcin (OC) levels. CONCLUSION: Vitamin D administration decreases DPD, PINP and ALP levels, indicating a reduced bone turnover following the intervention. Other BTMs, for example, CTX or OC values, were not affected by vitamin D prescription. Vitamin D supplementation may exert a positive effect on some important BTMs.

Targeting aging with the healthy skeletal system: The endocrine role of bone.

Aging is an inevitable biological process, and longevity may be related to bone health. Maintaining strong bone health can extend one's lifespan, but the exact mechanism is unclear. Bone and extraosseous organs, including the heart and brain, have complex and precise communication mechanisms. In addition to its load bearing capacity, the skeletal system secretes cytokines, which play a role in bone regulation of extraosseous organs. FGF23, OCN, and LCN2 are three representative bone-derived cytokines involved in energy metabolism, endocrine homeostasis and systemic chronic inflammation levels. Today, advanced research methods provide new understandings of bone as a crucial endocrine organ. For example, gene editing technology enables bone-specific conditional gene knockout models, which allows the study of bone-derived cytokines to be more precise. We systematically evaluated the various effects of bone-derived cytokines on extraosseous organs and their possible antiaging mechanism. Targeting aging with the current knowledge of the healthy skeletal system is a potential therapeutic strategy. Therefore, we present a comprehensive review that summarizes the current knowledge and provides insights for futures studies.

Circulating Osteocalcin Fractions are Associated with Vascular Calcification and Mortality in Chronic Hemodialysis Patients.

BACKGROUND: Vascular calcification, a component of chronic kidney disease-mineral and bone disorder (CKD-MBD), is prevalent in patients with end-stage kidney disease (ESKD) and contributes to high mortality. However, the association between the blood level of total osteocalcin (OC) and vascular calcification and mortality remains inconclusive. We, therefore, investigated whether different OC fractions can serve as biomarkers of vascular calcification and mortality in the ESKD population. METHODS: This observational cohort study enrolled patients on maintenance hemodialysis. Plasma carboxylated OC (cOC), uncarboxylated OC (ucOC), and intact parathyroid hormone (PTH) were measured. The percentage of carboxylated OC (%cOC) was calculated as dividing cOC by total OC. The vascular calcification severity was defined by an aortic calcification grade. The patients were followed for three years and one month. RESULTS: A total of 184 patients were enrolled. In the multivariable logistic regression, plasma %cOC, but not cOC or ucOC, was independently associated with the severity of vascular calcification (OR 1.019, p = 0.036). A significant U-shaped correlation was found between plasma %cOC and PTH (p = 0.002). In the multivariable Cox regression, patients with higher plasma %cOC had a higher risk of mortality (quartiles Q4 versus Q1-Q3, HR 1.991 [95% CI: 1.036-3.824], p = 0.039). CONCLUSIONS: In patients undergoing chronic hemodialysis, plasma %cOC positively correlated with vascular calcification and exhibited a U-shaped correlation with PTH. Furthermore, a higher plasma %cOC was associated with increased mortality. These findings suggest that plasma %cOC may serve as a biomarker for CKD-MBD and a predictor of clinical outcomes in chronic hemodialysis patients.

Non-psychoactive Cannabidiol Prevents Osteoporosis in an Animal Model and Increases Cell Viability, Proliferation, and Osteogenic Gene Expression in Human Skeletal Stem and Progenitor Cells.

Cannabidiol (CBD), the non-psychoactive component of the Cannabis sativa plant, is marketed as a potential therapeutic agent and has been studied for its roles in reducing inflammation and managing neuropathic pain. Some studies have reported that CB1 and CB2 receptor activation can attenuate and reverse bone loss in experimental animal models. Despite this, little is known about the impact of CBD on fracture healing. We investigated the effects of CBD in vitro using human osteoprogenitor cells and in vivo via murine femur fracture and osteoporosis models. In vitro mesenchymal stem cells were treated with increasing concentrations of crystalized pharmaceutical grade CBD or vehicle solution. Cell viability and proliferation were significantly increased in cells treated with CBD compared to vehicle control. Osteocalcin expression was also significantly higher in the CBD-treated human stem cells compared to vehicle control. In vivo the effect of CBD on bone mineral density and fracture healing in mice was examined using a two-phase experimental approach. Fluoxetine was used for pharmacologic induction of osteoporosis and surgical oophorectomy (OVX) was used for hormonal induction of osteoporosis. X-ray and microCT analysis showed that CBD prevented both fluoxetine- and OVX-induced osteoporosis. We found that while OVX resulted in delayed bone healing in control mice, CBD-pretreated mice exhibited normal bone healing. Collectively these in vitro and in vivo findings suggest that CBD exerts cell-specific effects which can be exploited to enhance bone metabolism. These findings also indicate that CBD usage in an osteoporotic population may positively impact bone morphology, warranting further research.

A Systematic Review of the Circadian Rhythm of Bone Markers in Blood.

There exists a marked circadian variation for several bone markers (BM), which is influenced by endogenous as well as exogenous factors including hormones, physical activity, and fasting. Consequently, was the aim of this review to provide an overview of the knowledge of the circadian variation of BM and which factors influence this rhythmicity. A systematic search of PubMed was performed for studies evaluating the circadian variation of BM and which factors influence this rhythmicity. The studies were screened for eligibility by a set of predetermined criteria including a list of relevant BM and a minimum study duration of 24 h with at least 3 blood samples of which two should be at least 6 h apart. In total were 29 papers included. There exists a marked circadian variation for most BM including Carboxy-terminal Cross-Linked Telopeptide of Type I Collagen (CTX) and osteocalcin (OC) with nighttime or early morning peak. Pro-collagen Type I N-terminal Propeptide (PINP) and PTH also showed circadian rhythm but with less amplitude. The inter-osteoblast-osteoclast regulatory markers such as OPG, RANKL, FGF23, and sclerostin showed no circadian rhythm. The markers were differently affected by exogenous factors like fasting, which greatly reduced the circadian variation of CTX but did not affect PINP or OC. The marked circadian variation and the factors which influence the rhythmicity, e.g., fasting are of great consequence when measuring BM. To reduce variation and heighten validity should circadian variation and fasting be kept in mind when measuring BM.

Vitamin K insufficiency predicts incidence of frailty in community-dwelling older adults: The Otassha Study.

INTRODUCTION: Vitamin K is a fat-soluble vitamin discovered as an essential factor for blood coagulation. It is suggested that vitamin K can benefit several aging-related diseases, including osteoporosis, osteoarthritis, and dementia. We previously reported the cross-sectional association of vitamin K insufficiency with frailty in community-dwelling older adults. MATERIALS AND METHODS: In October 2020, a health examination of community-dwelling older adults (The Otassha Study) was performed, including frailty evaluation and blood tests. We used a ucOC and OC ratio (ucOC/OC) to indicate vitamin K insufficiency. One year later, we conducted a follow-up evaluation of frailty on 518 people who were not frail at baseline. The serum ucOC/OC at the baseline examination was divided into quartiles (Q1, Q2, Q3, and Q4). Odds ratio (OR) and 95% confidence interval (CI) were calculated using multivariate binary logistic regression for each quartile of ucOC/OC to determine the risk of incident frailty in the follow-up study, with the lowest quartile (Q1) as the reference. RESULTS: Among the 518 older adults who were not frail at baseline, 66 people (12.7%) became frail in the follow-up study. In the multivariate binary logistic regression analysis, setting the lowest quartile of ucOC/OC (Q1) as a reference, the OR of the incident frailty in the highest quartile (Q4) was 2.53 (95% CI 1.07, 4.92) which was significantly different from Q1. CONCLUSION: The findings of this longitudinal study suggest that vitamin K insufficiency has nutritional importance in predicting the future incidence of frailty in the Japanese older adult population.