Search Results (415)

Heterotopic ossification (HO) refers to the pathological formation of bone in soft tissues, typically following trauma, surgical procedures, or as a result of genetic disorders. Notably, injuries to the central nervous system significantly increase the risk of HO, a condition referred to as neurogenic HO (NHO). This review outlines the cellular and molecular mechanisms driving HO, focusing on the inflammatory response, progenitor cell reprogramming, and current treatment strategies. HO is primarily fuelled by a prolonged and dysregulated inflammatory response, characterized by sustained expression of osteoinductive cytokines secreted by M1 macrophages. These cytokines promote the aberrant differentiation of fibro-adipogenic progenitor cells (FAPs) into osteoblasts, leading to ectopic mineralization. Additional factors such as hypoxia, BMP signalling, and mechanotransduction pathways further contribute to extracellular matrix (ECM) remodelling and osteogenic reprogramming of FAPs. In the context of NHO, neuroendocrine mediators enhance ectopic bone formation by influencing both local inflammation and progenitor cell fate decisions. Current treatment options such as nonsteroidal anti-inflammatory drugs (NSAIDs), radiation therapy, and surgical excision offer limited efficacy and are associated with significant risks. Novel therapeutic strategies targeting inflammation, neuropeptide signalling, and calcium metabolism may offer more effective approaches to preventing or mitigating HO progression. Full article

Sarcopenia is a progressive age-related musculoskeletal disorder characterized by loss of muscle mass, strength, and physical performance, contributing to functional decline and increased risk of disability. Emerging evidence suggests that vitamin D (Vit D) plays a pivotal role in skeletal muscle physiology beyond its classical functions in bone metabolism. This review aims to critically analyze the relationship between serum Vit D levels and sarcopenia in older adults, focusing on pathophysiological mechanisms, diagnostic criteria, clinical evidence, and preventive strategies. An integrative narrative review of observational studies, randomized controlled trials, and meta-analyses published in the last decade was conducted. The analysis incorporated international diagnostic criteria for sarcopenia (EWGSOP2, AWGS, FNIH, IWGS), current guidelines for Vit D sufficiency, and molecular mechanisms related to Vit D receptor (VDR) signaling in muscle tissue. Low serum 25-hydroxyvitamin D levels are consistently associated with decreased muscle strength, reduced physical performance, and increased prevalence of sarcopenia. Although interventional trials using Vit D supplementation report variable results, benefits are more evident in individuals with baseline deficiency and when combined with protein intake and resistance training. Mechanistically, Vit D influences muscle health via genomic and non-genomic pathways, regulating calcium homeostasis, mitochondrial function, oxidative stress, and inflammatory signaling. Vit D deficiency represents a modifiable risk factor for sarcopenia and functional impairment in older adults. While current evidence supports its role in muscular health, future high-quality trials are needed to establish optimal serum thresholds and dosing strategies for prevention and treatment. An individualized, multimodal approach involving supplementation, exercise, and nutritional optimization appears most promising. Full article

Osteoclastogenesis—the activation and differentiation of osteoclasts—is one of the pivotal processes of bone remodeling and is regulated by RANKL/RANK signaling, the decoy function of osteoprotegerin (OPG), and a cascade of pro- and anti-inflammatory cytokines. The disruption of this balance leads to pathological bone loss in diseases such as osteoporosis and rheumatoid arthritis. FFAR4 (Free Fatty Acid Receptor 4), a G protein-coupled receptor for long-chain omega-3 fatty acids, has been confirmed as a key mediator of metabolic and anti-inflammatory effects. This review focuses on how FFAR4 acts as the selective receptor for the omega-3 fatty acid docosahexaenoic acid (DHA). It activates two divergent signaling pathways. The Gαq-dependent cascade facilitates intracellular calcium mobilization and ERK1/2 activation. Meanwhile, β-arrestin-2 recruitment inhibits NF-κB. These collective actions reshape the cytokine environment. In macrophages, DHA–FFAR4 signaling lowers the levels of TNF-α, interleukin-6 (IL-6), and IL-1β while increasing IL-10 secretion. Consequently, the activation of NFATc1 and NF-κB p65 is profoundly suppressed under TNF-α or RANKL stimulation. Additionally, DHA modulates the RANKL/OPG axis in osteoblastic cells by suppressing RANKL expression, thereby reducing osteoclast differentiation in an inflammatory mouse model. Full article

Vitamin D is essential for calcium homeostasis, bone mineralization, immunity, and disease prevention. In a field study with Holstein-Friesian dairy cows, the impact of prepartum vitamin D₃ treatment on early postpartum placental gene expression, focusing on calcium metabolism, feto-placental growth, and immune response, had been investigated. Eight multiparous cows were treated with 10 mL vitamin D₃ (1 million IU cholecalciferol/mL) intramuscularly on day 273 of pregnancy, while eight others remained untreated and served as controls. Placental tissues were collected post-calving, and gene expression was analyzed using quantitative real-time PCR. Among 23 genes, 5 showed significant downregulation in the treated group: CaBP-9k (reduced by 88.1% from 32.80 ± 91.50 to 3.90 ± 8.54), ESR1 (reduced by 95.7% from 7.89 ± 17.87 to 0.34 ± 0.34), LHR (reduced by 96.5% from 3.75 ± 5.45 to 0.13 ± 0.17), NOD1 (reduced by 94.1% from 4.21 ± 7.00 to 0.25 ± 0.30), and TLR1 (reduced by 99.7% from 24.80 ± 61.45 to 0.07 ± 0.08). These results suggest that vitamin D₃ supplementation affects key pathways related to calcium transport, reproductive function, and immune response in the bovine placenta. These molecular changes may help to explain improved calcium homeostasis and reduced postpartum complications, offering insights into how targeted nutritional interventions can enhance reproductive efficiency in high-producing dairy cows. Full article

Optimal dietary calcium (Ca) and phosphorus (P) requirements remain undetermined for Ningxiang pigs, a valuable indigenous Chinese breed. This study conducted a continuous feeding trial with two growth phases (grower: 30–50 kg; finisher: 50–80 kg) using fixed Ca/P ratios to systematically evaluate the effects of Ca/P levels on growth performance and mineral metabolism. A total of 180 pigs per phase were allocated to four Ca/P levels. During the grower phase, a dietary regimen of 0.83% Ca/0.67% P significantly increased the average daily feed intake (ADFI), average daily gain (ADG), and apparent total tract digestibility (ATTD) of energy and P. In the finisher phase, 0.60/0.48% Ca/P showed optimal growth performance, upregulated jejunal mineral transporters (CaSR and SLC34A2), enhanced bone mineralization (metatarsal ash content), and improved intestinal morphology (duodenal and jejunal villus height, jejunal villus surface area). This regimen also selectively enriched Peptostreptococcaceae abundance, indicating improved host–microbe interactions. Based on these findings, stage-specific nutritional strategies were recommended: 0.83% Ca/0.67% P during the grower phase and 0.60% Ca/0.48% P during the finisher phase. These protocols synergistically improve microbial ecology, intestinal function, and bone metabolism, thereby maximizing the growth potential of Ningxiang pigs. Full article

Background/Objectives: Recent data on long-term consequences of prematurity on bone health are conflicting. The aim of this study was to assess the metabolic bone profile and bone mineral density (BMD) in prepubertal children born prematurely and to examine possible associations between bone health parameters and perinatal morbidity factors. Methods: This cross-sectional observational study included 144 children of mean (SD) age 10.9 (1.6) years: 49 children born very preterm (≤32 gestational weeks), 37 moderate-to-late preterm (32⁺¹ to 36⁺⁶ gestational weeks), and 58 born at term (controls). Serum levels of calcium/Ca, phosphorus/P, alkaline phosphatase/ALP, 25-hydroxyvitamin D/25(OH)D, bone formation markers (osteocalcin/OC, procollagen type I C-terminal propeptide/PICP, and insulin growth factor-1/IGF-1), and bone resorption markers (serum tartrate-resistant acid phosphatase 5b/bone TRAP5band urinary calcium-to-creatinine ratio) were measured. Total-body and lumbar-spine BMD and BMD Z-scores were calculated using dual-energy X-ray absorptiometry/DXA. Results: Children born very preterm showed significantly higher ALP, OC, PICP, and bone TRAP5b levels compared to controls, as well as compared to children born moderate-to-late preterm. Total-body and lumbar-spine BMD Z-scores were significantly lower in the very preterm-born group compared to controls. Gestational diabetes, preeclampsia, and bronchopulmonary dysplasia were associated with lower total-body BMD in the very preterm-born population. Conclusions: Preterm birth is associated with impaired metabolic bone profile and lower total-body and lumbar-spine BMD in childhood. Moderate-to-late preterm-born children exhibit altered metabolic bone parameters compared to very preterm-born children. Further research in children might allow better insight into the long-term impact of preterm birth on bone health. Full article

Background/Objectives: Primary hyperparathyroidism (PHPT) has been associated with systemic inflammation and metabolic disturbances. This study aimed to evaluate changes in the Systemic Immune-Inflammation Index (SII) and Prognostic Nutritional Index (PNI) following parathyroidectomy (PTX) in PHPT patients, and to assess their return toward healthy control values. Materials and Methods: This retrospective study was conducted between January 2010 and March 2022. It analyzed the demographic characteristics, clinical findings, and laboratory results of patients diagnosed with and operated for PHPT, with comparisons to healthy controls. Postoperative values were recorded at least six months after surgery. Bone mineral density was classified according to World Health Organization criteria, and nephrolithiasis was assessed with imaging. Results: After applying exclusion criteria, 415 PHPT patients and 410 controls were included. PHPT patients were older (p < 0.001) and had a higher proportion of females (p = 0.016). Compared to controls, they had lower phosphorus, albumin, high-density lipoprotein cholesterol, total cholesterol, hemoglobin, and PNI (p < 0.001 for all), while triglycerides, monocytes, platelets, CRP, and SII were higher (p < 0.05). Postoperatively, albumin, platelets, total cholesterol, and triglycerides increased (p < 0.001), while calcium, white blood cell count, neutrophils, lymphocytes, and CRP decreased (p < 0.05), approaching healthy control values. In age- and sex-matched comparisons (propensity score matching, n = 259 in each group), platelets (p = 0.002) and hemoglobin (p = 0.018) were found to be higher postoperatively. Conclusions: Preoperative SII and PNI levels were significantly altered in PHPT patients compared to healthy controls. Following PTX, both of these markers and other parameters showed significant improvements, reflecting positive changes in systemic inflammation and nutritional status. Full article

Background/Objectives: Bisphosphonates may influence vascular calcification and atheroma formation via farnesyl pyrophosphate synthase inhibition in the mevalonate pathway regulating bone and lipid metabolism. However, the clinical impact of NCB use on cardiovascular outcomes remains uncertain, largely due to methodological heterogeneity in prior studies. We aimed to evaluate the association between nitrogen-containing bisphosphonate (NCB) therapy and coronary artery calcium (CAC) progression, as well as the incidence of cardiovascular disease (CVD) and coronary heart disease (CHD) events. Methods: From 6814 participants in MESA Exam 1, we excluded males (insufficient male NCB users in the MESA cohort), pre-menopausal women, baseline NCB users, and users of hormone replacement therapy, raloxifene, or calcitonin. Among 166 NCB initiators and 1571 non-users with available CAC measurements, propensity score matching was performed using the available components of FRAX, namely age, race, BMI, LDL cholesterol, alcohol, smoking, and steroid use, and baseline CAC yielded 165 NCB initiators matched to 473 non-users (1:3 ratio). Linear mixed-effects models evaluated CAC progression, and Cox models analyzed incident CVD and CHD events. Results: In the overall cohort, NCB use was not significantly associated with CAC progression (annual change: −0.01 log Agatston units; 95% CI: −0.05 to 0.01). However, among participants with a baseline estimated glomerular filtration rate (eGFR) < 65 mL/min/1.73 m², NCB use was associated with attenuated CAC progression compared with non-users (−0.06 log Agatston units/year; 95% CI: −0.12 to −0.007). No significant association was observed between NCB use and incident CVD events in the overall cohort (HR: 0.90; 95% CI: 0.60−1.36) or within kidney function subgroups. Conclusions: Incident NCB use among postmenopausal women with mild or no CAC at baseline was associated with reduced CAC progression only in women with impaired kidney function. However, this association did not correspond to a decreased risk of subsequent cardiovascular events, suggesting that the observed imaging benefit may not translate into meaningful clinical association. Full article

Background: Vitamin D is a steroid hormone, essential for the immune system and bone health. Since the sun is meant to provide at least 80% of daily vitamin D requirements, the COVID-19 pandemic is likely to have induced a considerable influence on calcium metabolism. Methods: We analyzed data from 1138 children, seen in an outpatient pediatric endocrinology clinic from 2022–2023. Vitamin D status was classified as deficiency if 25(OH)D ≤ 20 ng/mL, insufficiency < 30 ng/mL, and sufficiency ≥ 30 ng/mL. Results: Overall, 60.8% of children had vitamin D deficiency or insufficiency worsened with age (p < 0.005), and with adolescent males having higher 25(OH)D concentrations than females (p < 0.05). A negative correlation was found between 25(OH)D and BMI SDS (R² = 0.02, p < 0.001), and 25(OH)D concentrations varied seasonally, decreasing in winter. Subclinical hyperparathyroidism [parathyroid hormone (PTH) > 45 pg/mL) and normal calcium] was found in 21.5% of children, with 73.5% of them being vitamin D deficient or insufficient. A negative correlation between PTH and 25(OH)D was observed, with PTH plateauing at 25(OH)D above 40 ng/mL (p < 0.001). Conclusions: Compared to the pre-pandemic data (2016–2018), with only 5.1% of children having subclinical hyperparathyroidism (p < 0.001), these findings suggest a marked deterioration in vitamin D status and calcium metabolism in children, with possible unforeseen consequences for bone, immune, and general health. Full article

Novel three-dimensional porous composites of alginate–pectin (A/P) with zinc- or manganese-substituted hydroxyapatites (A/P-ZnHA and A/P-MnHA) were synthesized via lyophilization and calcium cross-linking. Powder X-ray diffraction and infrared spectroscopy analyses confirmed single-phase apatite formation (crystallite sizes < 1 µm), with ZnHA exhibiting lattice contraction (*c*-axis: 6.881 Å vs. 6.893 Å for HA). Mechanical testing revealed tunable properties: pristine A/P sponges exhibited an elastic modulus of 4.7 MPa and a tensile strength of 0.10 MPa, reduced by 30–70% by HA incorporation due to increased porosity (pore sizes: 112 ± 18 µm in the case of MnHA vs. 148 ± 23 µm-ZnHA). Swelling capacity increased 2.3–2.8-fold (125–155% vs. 55% for A/P), governed by polysaccharide interactions. Scanning electron microscopy investigation showed microstructural evolution from layered A/P (<100 µm) to tridimensional architectures with embedded mineral particles. The A/P-MnHA composites demonstrated minimal cytotoxicity for the NCTC cells and good viability of dental pulp stem cells, while A/P-ZnHA caused ≈20% metabolic suppression, attributed to hydrolysis-induced acidification. Antibacterial assays highlighted A/P-MnHA′s broad-spectrum efficacy against Gram-positive (Bacillus atrophaeus) and Gram-negative (Pseudomonas protegens) strains, whereas A/P-ZnHA targeted only the Gram-positive strain. The developed composite sponges combine cytocompatibility and antimicrobial activity, potentially advancing osteoplastic materials for bone regeneration and infection control in orthopedic/dental applications. Full article

Background/Objectives: Children with congenital adrenal hyperplasia (CAH) face significant risks of impaired growth and metabolic disturbances despite standard glucocorticoid therapy. This cross-sectional study aimed to evaluate growth outcomes, nutritional status, and associated factors among children with CAH treated in a Vietnamese tertiary pediatric center. Methods: We assessed 201 children aged 1.1–16.5 years in a tertiary pediatric center in Vietnam for anthropometric parameters, biochemical markers (calcium, phosphate, 25-hydroxyvitamin D), and clinical features. Growth status was evaluated using WHO standards, and bone age was assessed radiographically. Statistical analyses explored associations between growth outcomes and clinical, biochemical, and treatment-related factors. Results: Stunting was present in 16.4% of children, while 53.3% were overweight or obese. Bone age advancement occurred in 51.7% of cases. Vitamin D insufficiency or deficiency was detected in 85.6% of patients, and hypocalcemia was present in 85.1%. Overweight/obesity, vitamin D deficiency, and bone age advancement were associated with older age, prolonged corticosteroid therapy, higher androgen levels, and clinical features of treatment imbalance (e.g., Cushingoid appearance, hyperpigmentation). Female sex was significantly associated with higher rates of stunting. Conclusions: Growth impairment, nutritional deficiencies, and skeletal maturation disturbances are prevalent among children with CAH in Vietnam. Early identification of risk factors and the implementation of tailored management strategies that address both endocrine and nutritional health are crucial for optimizing long-term outcomes. Full article

It is now widely recognized that maintaining magnesium (Mg) homeostasis is critical for health, especially in the context of chronic kidney disease (CKD). Patients with CKD commonly develop hyperphosphatemia and secondary hyperparathyroidism, which are controlled by therapies targeting intestinal phosphate absorption and circulating calcium levels or by modulating parathyroid calcium sensing. Notably, Mg supplementation may provide dual benefits by promoting bone formation and maintaining normal mineralization with slightly elevated serum levels. Importantly, low Mg levels are associated with mortality risk in CKD, highlighting the importance of maintaining adequate serum Mg levels in these patients. Particularly, kidney transplant (KT) patients have lower circulating Mg levels, likely due to interactions with immunosuppressive treatments. Sodium-glucose co-transporter 2 (SGLT2) inhibitors have shown survival benefits in CKD and increased serum Mg levels, suggesting that Mg regulation may contribute to these outcomes. Overall, Mg plays a key role in CKD-associated mineral and bone disorders (CKD-MBD). Thus, understanding the mechanisms underlying the alteration of Mg homeostasis in CKD could improve clinical outcomes. This review summarizes the basic and clinical studies demonstrating (1) the key actions of Mg in CKD-MBD, including secondary hyperparathyroidism and bone abnormalities; (2) the distinctive profile of KT patients for Mg homeostasis; and (3) the interaction between commonly used drugs, such as SGLT2 inhibitors or immunosuppressive treatments, and Mg metabolism, providing a broad understanding of both the key role of Mg in the context of CKD and the treatments that should be considered to manage Mg levels in CKD patients. Full article

Floating aquatic vegetation and algal blooms are increasing with global warming, potentially reducing UVB exposure and, consequently, vitamin D (vit-D) synthesis in freshwater turtles. Vit-D mediates calcium metabolism and overall health, yet the effects of floating aquatic vegetation on vit-D levels remain unclear, as is whether turtles actively avoid habitats with abundant floating vegetation. Here, we address these questions by quantifying vit-D₃ levels in the blood of adult female painted turtles (Chrysemys picta) exposed to high-vegetation (darker/colder) or clear-water (lighter/warmer) treatments for one month outdoors and one month indoors at a single temperature during late summer and early fall. The observed circulating vit-D₃ levels resembled those reported for other freshwater turtles, declined over time in both treatments, and were marginally lower under high vegetation after 60 days compared to clear water. However, this difference disappeared after correcting for lymph contamination and multiple comparisons, suggesting that perhaps adult females are robust to the effect of floating vegetation, but whether they were buffered by vit-D₃ stores in lipids is unclear. Additionally, in subsequent years, females were exposed to habitat choice experiments and exhibited a strong preference for high floating vegetation over clear water, both as a group (outdoors) and individually (outdoors, and indoors at 21 °C and 26 °C), consistent with known benefits conferred by floating vegetation (food, predator avoidance). While no ill effects of high vegetation nor behavioral avoidance were detected here, longer experiments at different seasons on both sexes and varying ages are warranted before concluding whether painted turtles are truly resilient in their vit-D levels or if, instead, a tradeoff exists between the known benefits of floating vegetation and potential [yet unidentified] detrimental effects (lower dissolved oxygen or vit-D) when vegetation is overgrown for extended periods. Full article

In patients with chronic kidney disease (CKD), cardiovascular events (CVA) are the main cause of morbidity and mortality. Vascular calcification, linked to bone mineral metabolism disorders such as elevated serum phosphate, parathyroid hormone (PTH), and FGF23, well-known uremic toxins, aggravate this risk. Calcimimetics are allosteric activators of the calcium-sensing receptor (CaSR), a G protein-coupled receptor that regulates PTH secretion and synthesis in response to changes in extracellular calcium in the parathyroid glands. Through direct and indirect mechanisms, they have demonstrated their efficacy in reducing the progression of vascular, valvular, and soft tissue calcification in experimental studies. Although clinical studies in dialysis patients did not achieve statistical significance in their primary objectives, positive results in subgroup analyses suggest that the lack of significance may be attributable to the short follow-up period. This finding highlights the need to consider early treatment strategies, especially in advanced stages of chronic kidney disease, to more effectively address the progression of vascular calcification through serum uremic toxins control. Full article

Objective: Growth retardation in adolescents caused by nutritional deficiency requires effective intervention. A novel dietary supplement containing bamboo shoot extract, amino acids, and calcium citrate (Kidtal + Ca, KDTCa) was evaluated for its growth-promoting effects. Methods: After acclimatization, sixty-three 3-week-old male Sprague-Dawley (SD) rats were randomly divided into a normal control group and model groups. Growth retardation was induced in the modeling groups through calcium-deficient feeding, followed by administration of KDTCa, bamboo shoot extract and amino acids (Kidtal), or calcium citrate (CC). After 6 weeks of intragastric administration, the mechanical properties, microstructure, and growth plate development of bone were evaluated using three-point bending, micro-CT, and H&E staining, respectively. Bone calcium/phosphorus distribution and fecal calcium apparent absorption rate were measured by ICP-MS. Results: All inter-group differences were analyzed using one-way analysis of variance and checked using the Tuckey test. KDTCa treatment dose-dependently enhanced bone development in calcium-deficient rats. Compared to the model group, H-KDTCa significantly restored naso-anal length (p < 0.05) and body weight (p < 0.01). KDTCa supplementation significantly restored calcium and phosphorus levels in blood and bone. Three-point bending experiments showed that the stiffness and bending energy were increased by 142.58% and 384.7%. In bone microarchitecture, both bone mineral density (BMD) and microstructural parameters were significantly improved. These findings were consistent with the increased long bone length (p < 0.05) and decreased serum BALP/TRACP levels (p < 0.001). Dose-dependent IGF-1 elevation (p < 0.01) potentially mediated growth plate elongation by 35.34%. Notably, KDTCa increased calcium apparent absorption by 6.1% versus calcium-only supplementation at equal intake. Conclusions: KDTCa improves bone microstructure and strength, restores bone metabolism, and enhances growth plate height via promoting IGF-1 secretion to facilitate bone development. Further studies are needed to determine whether the components and calcium in Kidtal have a synergistic effect. Full article