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Purpose: To test the hypothesis that training with reduced carbohydrate (CHO) availability increases bone resorption in adolescent soccer players. Methods: In a randomised crossover design, ten male players (age: 17.4 ± 0.8 years) from an English Premier League academy completed an acute 90-min field-based training session (occurring between 10:30–12:00) in conditions of high (TRAIN HIGH; 1.5 g.kg−1, 60 g, 1.5 g.kg−1 and 1.5 g.kg−1 consumed at 08:00, during training, 12:30 and 13:30, respectively) or low CHO availability (TRAIN LOW; 0 g.kg−1). Participants also completed a non-exercise trial (REST) under identical dietary conditions to TRAIN LOW. Venous blood samples were obtained at 08:30, 10:30, 12:30 and 14:30 for assessment of bone resorption (βCTX), bone formation (PINP) and calcium metabolism (PTH and ACa). Results: External training load did not differ (all P > 0.05) between TRAIN HIGH and TRAIN LOW, as evident for total distance (5.6 ± 0.8; 5.5 ± 0.1 km), average speed (81 ± 9; 85 ± 12 m.min−1) and high-speed running (350 ± 239; 270 ± 89 m). Area under the curve for both βCTX and PINP was significantly greater (P < 0.01 and P = 0.03) in TRAIN LOW versus TRAIN HIGH, whilst no differences in PTH or ACa (P = 0.11 and P = 0.89) were observed between all three trials. Conclusion: CHO restriction before, during and after an acute soccer training session increased bone (re)modelling markers in academy players. Despite acute anabolic effects of bone formation, the long-term consequence of bone resorption may impair skeletal development and increase injury risk during growth and maturation. [ABSTRACT FROM AUTHOR]

Benign Paroxysmal Positional Vertigo (BPPV) is a common vestibular disorder characterized by vertigo episodes due to head position changes. Emerging research suggests a link between Vitamin D deficiency and BPPV, attributed to Vitamin D's role in calcium metabolism essential for inner ear function. This study investigates the relationship between Vitamin D levels and the incidence, severity, and recurrence of BPPV. This year-long prospective cohort study was conducted at a tertiary care center, enrolling 100 patients diagnosed with BPPV. Vitamin D levels were measured and classified as deficient, insufficient, or sufficient. Patients identified with Vitamin D deficiency (< 20 ng/mL) received supplementation at a dose of 2000 IU daily for six months. Participants were followed monthly for one year to monitor the incidence and severity of BPPV episodes, assessed using the Vertigo Symptom Scale, and recurrence rates. Statistical analysis included Kaplan-Meier curves, log-rank tests, and Cox proportional hazards models to evaluate the Vitamin D-BPPV relationship. The study revealed that patients with Vitamin D deficiency (< 20 ng/mL) had a 71% incidence of BPPV, compared to 20% in those with sufficient levels. The average severity score was higher in the deficient group (7.5) versus the sufficient group (3.5). Vitamin D supplementation correlated with reduced BPPV incidence and severity over time. The findings indicate a significant link between Vitamin D deficiency and increased BPPV incidence and severity, highlighting Vitamin D's role in vestibular health. These results suggest that Vitamin D supplementation could be integral to BPPV management. Further research, including controlled studies, is needed to understand the mechanisms behind these associations and their clinical implications. [ABSTRACT FROM AUTHOR]

Vitiligo is an autoimmune skin disease that can be influenced by stress, including that resulting from sleep deprivation and sleep disturbances. Sleep is essential in the regulation of several hormonal, metabolic and autoimmune pathways that may have important roles in vitiligo. This study aimed to investigate the potential interplay between hormonal, metabolic, and autoimmune markers in vitiligo patients, and the possible influence of sleep quality in these vitiligo pathways. A cohort of 30 vitiligo patients and 26 healthy controls were assessed for various laboratory markers, including thyroid-stimulating hormone (TSH), parathyroid hormone (PTH), serum calcium, 1.25(OH)2D, 25(OH)D, anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-TG), and antinuclear antibodies (ANA). The study evaluated sleep quality using the Pittsburgh Sleep Quality Index (PSQI). Positive anti-TPO were found in the vitiligo group, but did not in the control group. Vitamin D 25(OH)D mean levels were clinically insufficient in both groups (< 30 mg/dL). Reactive ANA was analyzed with 2 variables related to vitiligo: phototherapy and skin activity. No statistical correlation was found in the chi-square test on this relationship. Descriptive findings have shown that the positivity to anti-TPO and anti-TG, associated or not with reactive ANA, was higher in vitiligo group. Great part (85.7%) of vitiligo group were “poor sleepers” (PSQI > 5), which has increased (88.2%) when considering only individuals with signs of vitiligo activity. Autoimmune hypothyroidism and positive anti-TPO are expected in vitiligo, although this marker is not usually measured in the first laboratory screening to this disease. Adequate vitamin D levels may be a key adjuvant in skin pigmentation, and be related to sleep quality and immune regulation, as this vitamin can be related to better sleep and immunomodulation in autoimmune diseases. Evaluating ANA before phototherapy can be controversial, but it should be considered in cases with a poor response to this treatment, or when there is a higher risk of other autoimmune diseases. Poor sleep predominated in the vitiligo group, based on PSQI scores that reported worse subjective sleep in these patients. Worse sleep predominated in individuals with signs of skin activity and reactive autoimmune markers. Screening these components could be important in the management of vitiligo, as maintaining body homeostasis can help to improve the disease course. Sleep should be considered as a potential modulator of several multidirectional vitiligo pathways. [ABSTRACT FROM AUTHOR]

Hypophosphatasia (HPP) is a rare, inherited, and systemic disorder characterized by impaired skeletal mineralization and low tissue nonspecific serum alkaline phosphatase (TNSALP) activity. It is caused by either autosomal recessive or dominant‐negative mutations in the gene that encodes TNSALP. The phenotype of HPP is very broad including abnormal bone mineralization, disturbances of calcium and phosphate metabolism, pain, recurrent fracture, short stature, respiratory impairment, developmental delay, tooth loss, seizures, and premature death. Other than supportive care, there has been no disease‐specific treatment available for those with HPP. Asfotase alfa is a fully humanized, recombinant enzyme replacement therapy for the management of HPP. It is available in several countries for the treatment of the more severe forms of HPP, namely perinatal and infantile HPP. This review will summarize the preclinical data on asfotase alfa and highlight the data from clinical trials and case reports. These data show the transformative nature of asfotase alfa when administered as part of an interdisciplinary treatment model. [ABSTRACT FROM AUTHOR]

(-)-Epigallocatechin-3-O-gallate (EGCG), one of the green tea catechins, exhibits significant antioxidant properties that play an essential role in various diseases. However, the functional role and underlying mechanism of EGCG in stimulating of hepatic stellate cells (HSCs) remain unexplored in transcriptomics sequencing studies. The present study suggests that oral administration of EGCG at a dosage of 200 mg/kg/day for a duration of four weeks exhibits significant therapeutic potential in a murine model of liver fibrosis induced by CCl4. The activation of HSCs in vitro was dose-dependently inhibited by EGCG. The sequencing analysis data reveled that EGCG exerted a regulatory effect on the calcium signal in mouse HSCs, resulting in a decrease in calcium ion concentration. Further analysis revealed that EGCG inhibited the expression of phospholipase C epsilon-1 (PLCE1) and inositol 1, 4, 5-trisphosphate (IP3) in activated mouse HSCs. Additionally, EGCG contributes to the reduction the concentration of calcium ions by regulating PLCE1. After the knockdown of PLCE1, free calcium ion concentrations decreased, resulting in the inhibition of both cell proliferation and migration. Interestingly, the expression of PLCE1 and cytosolic calcium levels were regulated by reactive oxygen species(ROS). Furthermore, our findings suggest that ROS might inhibit the expression of PLCE1 by inhibiting TFEB, a transcription activator involved in the nuclear translocation process. Our study provided novel evidence regarding the regulatory effects of EGCG on activated HSCs (aHSCs) in mice by the calcium signaling pathway, emphasizing the crucial role of PLCE1 within the calcium signaling network of HSCs. The proposition was also made that PLCE1 holds promise as a novel therapeutic target for murine liver fibrosis. [ABSTRACT FROM AUTHOR]

Asymptomatic primary hyperparathyroidism (PHPT) involves 80–90% of the parathyroid tumor-associated cases of PHPT in the modern medical era, while normocalcemic PHPT (NPHPT) has a prevalence of 0.1–11%. We aimed to analyze the bone status and mineral metabolism in NPHPT amid conservative or surgical management. In this narrative review, we searched PubMed (between January 2020 and July 2024) via different keywords. Fourteen studies from the final analysis (388 patients with NPHPT; 1188 with PHPT; and 803 controls) showed that mean serum calcium levels varied between 2.57 and 2.26 mmol/L in NPHPT. Ten studies identified a similar 24 h urinary calcium in NPHPT versus hypercalcemic PHPT (HPHPT). Except for one study, a mandatory vitamin D analysis was performed, but the 25-hydroxyvitamin D cut-offs varied. Osteoporosis (n = 6 studies; N = 172 with NPHPT) was confirmed in 41.7–100% of NPHPT subjects. In surgery candidates, this rate might be overestimated. A DXA analysis was performed in eight studies (235 subjects with NPHPT, and 455 patients with HPHPT); two studies identified a lower BMD in HPHPT < NPHPT, but the results were not homogenous. A single study analyzed the TBS and found similar results in NPHPT. The prevalence of fractures (n = 9) varied between 7.4% and 42.8% in NPHPT. Bone turnover markers (N = 262 patients, n = 8 studies) showed lower bone formation markers in NPHPT versus PHPT (n = 3). Two studies analyzed the BMD and bone turnover markers following parathyroidectomy (161 patients, including 30 patients with NPHPT; mean ages over 60 years). To conclude, given the wide spectrum of complications associated with PHPT, an early diagnosis and proper management is essential. A more extensive screening in patients with osteoporosis and kidney stones might lead to the discovery of NPHPT, a more recently described form of PHPT. While it is still unclear whether NPHPT is an early stage of HPHPT or a separate entity, recent findings show similar osteoporosis and fracture occurrence, and an improvement in bone metabolism, following parathyroidectomy. More extensive prospective studies are crucial to understand the natural course of the disease, to reach a consensus regarding parathyroidectomy indications and surgery candidates' selection, and to ensure proper personalized management for these patients. With the evolving diagnosis methods, PHPT has become a condition with a changing clinical presentation, which now requires modern evaluation and treatment approaches. [ABSTRACT FROM AUTHOR]

Androgen receptors are expressed in the kidney and serum testosterone is negatively associated with serum phosphate in males, suggesting a role of testosterone in renal phosphate handling. In this cross‐sectional study, we examined the association of serum total and free testosterone with acute phosphate and calcium excretion in males in response to an oral phosphate challenge. Thirty‐five healthy adult males with normal baseline testosterone levels consumed a 500 mg phosphorus drink and the urinary excretion of minerals, as well as levels of relevant circulating parameters, were assessed at baseline and hourly for 4 h. Serum total testosterone was positively associated with overall phosphate excretion (r = 0.35, p = 0.04) and calcium excretion (r = 0.44, p = 0.00) in response to the challenge. Serum free testosterone was positively associated with post‐challenge calcium excretion (r = 0.34, p = 0.048), but significance was not reached for phosphate excretion (r = 0.31, p = 0.07). Serum total and free testosterone were not associated with parathyroid hormone, fibroblast growth factor‐23, or vitamin D—key factors implicated in phosphate and calcium regulation. Overall, higher serum total testosterone levels in healthy middle‐aged males are associated with a greater capacity to acutely excrete phosphate and calcium after a single oral phosphate challenge, suggesting potential ramifications of testosterone deficiency related to mineral homeostasis. [ABSTRACT FROM AUTHOR]

In conversations about bone loss and the importance of calcium homeostasis, patients frequently inquire about the association with arterial calcifications. Although a relationship between bone loss and the occurrence of vascular calcifications is suspected, it is not yet fully investigated and understood. This study aims to analyze associations between bone mineralization, structure, and vascular calcification at the lower leg in patients with low bone mineral density in HR-pQCT. We retrospectively analyzed 774 high-resolution quantitative computed tomography (HR-pQCT) scans of the distal tibia for the presence of vascular calcifications. After sex-specific propensity score matching for age and BMI to account for confounders, 132 patients remained for quantification of bone microstructure, bone density, lower leg arterial calcification (LLAC), and laboratory parameters of bone turnover. The interactions between bone parameters and vascular calcification were quantified by regression analyses. The calcium metabolism was not different between individuals with and without LLAC, nor oral calcium supplementation. Female patients with LLAC had a higher cortical perimeter (p = 0.016) compared to female patients without LLAC, whereas male patients with LLAC had lower cortical pore diameter than male patients without LLAC (p = 0.027). The appearance of LLAC was sex specifically associated with bone parameters. In female patients, only plaque density was associated with HR-pQCT bone parameters and age, whereas in male patients, plaque volume was associated with HR-pQCT parameters of the distal tibia. Female patients exhibit an increasing plaque density depended on age and trabecular thinning. Decreasing cortical pore diameter and trabecular number along with increasing bone mineralization are linked to increasing plaque volume in male patients. [ABSTRACT FROM AUTHOR]

Keel bone fractures (KBF) are one of the most important welfare problems in commercial laying hens. Despite extensive research on the matter, its etiology remains unclear. Studying fracture characteristics in radiographic images can aid in the understanding of the disorder. The aim of the current study was to provide detailed description of fracture characteristics and explore ossification in the keel bone. In this descriptive study, repeated cross-sectional sampling was performed in one commercial laying hen flock. The flock was visited at 11 time points from 17–57 weeks of age (WOA), radiographing 30 laying hens at each visit resulting in altogether 330 unique radiographs. Fracture characteristics and the keel bone's level of ossification were assessed in each radiograph. In total, 344 fractures were recorded, of which 71.5% were complete and 28.5% were incomplete. Of the complete fractures, 82.9% were recorded as transverse, and 15.9% as oblique. One comminuted and two butterfly fractures were recorded. The caudal third of the keel was the most common area for fractures. Fracture characteristics differed between the different regions of the keel bone; all incomplete fractures in the cranial third appeared on the ventral surface of the keel, whilst the majority of incomplete fractures on the caudal third appeared on the dorsal surface. This indicates that the underlying etiology might differ between the cranial and caudal part. Folding fractures were observed in 18.6% of all the fractures, and occurred in both cranial-, and caudal third of the keel, indicating possible underlying disorders of calcium metabolism. All hens at 32 WOA and older had a fully ossified keel, based on radiographic evaluation. Displacement and soft tissue swelling are common characteristics in fractures of traumatic origin. We found a high frequency of simple fractures, without these characteristics, indicating that non-traumatic causes may be of higher importance than conventional beliefs. [ABSTRACT FROM AUTHOR]

The article discusses a pilot trial investigating the impact of vitamin D on glycaemic control in patients with type 2 diabetes. The study compared the effects of vitamin D-rich food, sun exposure, and commercial supplements on glycaemic control. Results showed that dietary intervention was most effective in increasing serum vitamin D levels, while both diet and supplement groups saw significant reductions in HbA1c levels. Sun exposure group showed benefits in blood lipid profiles. The study suggests that diet and vitamin D supplements can improve glycaemic control in type 2 diabetes patients. [Extracted from the article]

Background: Living kidney donors (LKD) experience an abrupt decline in glomerular filtration rate (GFR) resulting in abnormalities of mineral and bone metabolism (MBD), and this may have implications for skeletal health. We prospectively studied acute and long term MBD adaptation of LKD from two kidney transplant centers (São Paulo, Brazil and Miami, USA). Methods: Renal function and MBD parameters longitudinally after kidney donation (baseline – D0, day 1, 14, 180 and 360 post-operatively) were measured in 74 patients (40 y, 73% female, 54% Brazilian). A subset of 20 donors from Brazil were reassessed after 10 years of nephrectomy. Results: At baseline, Brazilian donors presented lower intact FGF23 (20.8 vs. 80.1 pg/mL, P < 0.01) and higher PTH (47.4 vs. 40.1, P = 0.04) than their US counterparts. GFR decreased to 63% of its baseline levels just after donation but improved 10% during the first year. PTH levels increased on D1, returning to baseline levels on D14, while FGF23 remained higher than baseline over the first year. LKD had a significant reduction of serum phosphate on D1, which returned to baseline levels on D180. A higher fractional excretion of phosphate (FEP) was noted since D14. After 10 years of donation, 20 LKD presented a sustained reduction in GFR (74.8 ± 14mL/min). There was a return to baseline in serum FGF23 [21.8 (18–30) pg/mL] and FEP, accompanied by an increase in serum calcium. PTH remained elevated (57.9 ± 18 pg/mL), whereas serum calcitriol and Klotho were lower than before the donation. Conclusions: The abrupt decline in kidney mass is associated with an increase in PTH and FGF23 that is not explained by phosphate retention. In a long-term evaluation, LKD showed a sustained drop in GFR, with lower serum calcitriol and Klotho, and higher PTH. The effects of these changes should be investigated in further studies. [ABSTRACT FROM AUTHOR]

Vascular calcification (VC) is common in patients with advanced chronic kidney disease (CKD).A series of factors, such as calcium and phosphorus metabolism disorders, uremic toxin accumulation, inflammation and oxidative stress and cellular senescence, cause osteoblast‐like differentiation of vascular smooth muscle cells, secretion of extracellular vesicles, and imbalance of calcium regulatory factors, which together promote the development of VC in CKD. Recent advances in epigenetics have provided better tools for the investigation of VC etiology and new approaches for finding more accurate biomarkers. These advances have not only deepened our understanding of the pathophysiological mechanisms of VC in CKD, but also provided valuable clues for the optimization of clinical predictors and the exploration of potential therapeutic targets. The aim of this article is to provide a comprehensive overview of the pathogenesis of CKD VC, especially the new advances made in recent years, including the various key factors mentioned above. Through the comprehensive analysis, we expect to provide a solid theoretical foundation and research direction for future studies targeting the specific mechanisms of CKD VC, the establishment of clinical predictive indicators and the development of potential therapeutic strategies. [ABSTRACT FROM AUTHOR]

Objective: Diabetic osteoporosis (DOP) is a metabolic disease that occurs in patients with diabetes due to insufficient insulin secretion. This condition can lead to sensory neuropathy, nephropathy, retinopathy, and hypoglycemic events, which can increase the risk of fractures. This study aimed to assess the effectiveness of Empagliflozin, a sodium–glucose cotransporter-2 (SGLT-2) inhibitor, in treating diabetic osteoporosis (DOP) and preventing fractures. Methods: This quasi-experimental study enrolled 100 patients with diabetic osteoporosis from February 2023 to February 2024. Participants were randomly assigned to an intervention group (n = 50) and a control group (n = 50). The intervention group received Empagliflozin in combination with symptomatic treatment, while the control group received only symptomatic treatment. The treatment duration was six months. Fasting blood glucose (FBG), 2-hour postprandial blood glucose (2 h PG), glycosylated hemoglobin A1c (Hb A1c), bone mineral density (BMD), serum phosphorus and calcium concentration were measured after the intervention and the incidence of fracture was followed up for 12 months. The data were analyzed using SPSS 23. Descriptive statistics (mean, standard deviation, and percentage) and analytical methods (t test, Chi square) were also used to analyze the data. Results: After six months of treatment, the intervention group exhibited significantly lower levels of FBG (P < 0.001), 2 h-PG (P = 0.001), and HbA1c (P < 0.001) than the control group. Additionally, bone mineral density, serum phosphorus, and calcium levels were significantly higher in the intervention group (P < 0.001). After a 12-months follow-up, the incidence of fractures in the intervention group was 2%, while it was 16.33% in the control group (P < 0.05). Conclusion: Empagliflozin, when combined with symptomatic treatment, demonstrates a positive clinical effect in patients with diabetic osteoporosis. The treatment effectively improves blood glucose metabolism, bone mineral density, and phosphorus and calcium metabolism, ultimately leading to a significant reduction in the incidence of fracture. [ABSTRACT FROM AUTHOR]

Diabetic osteoporosis (DOP) is a secondary disease that severely affects the health and quality of life of patients with diabetes mellitus. This study aimed to explore the bone protective effect of aqueous extract of Eucommia ulmoides (EUL) in DOP mice. DOP mice were established using a high‐sugar, high‐fat diet and streptozotocin (STZ) (35 mg/kg for three consecutive days), and the EUL aqueous extract (2.5 g/kg/day) was orally administered for 6 weeks. The serum levels of oxidative stress‐related factors, calcium, and phosphorus were assessed using biochemical assays. The osteoprotective effect of EUL was assessed using micro‐computer tomography, three‐point bending assay, histological analysis, and immunoblotting. Quantitative real‐time polymerase chain reaction and western blotting were performed to detect the expression levels of calcium transport channel factors in the kidney and small intestine tissues. Furthermore, the expression levels of nuclear factor erythroid 2‐related factor 2 (Nrf2) and heme oxygenase‐1 (HO‐1) in the femur, kidney, and small intestine tissues were detected using western blotting and quantitative real‐time polymerase chain reaction. EUL aqueous extract reduced blood glucose levels, increased body weight, and relieved symptoms in DOP mice (p <.05). It also increased bone mineral density, improved the bone microstructure, decreased the number of femoral osteoclasts, and increased the expression of femoral Runx2 and Bmp2 in DOP mice (p <.01). After 6 weeks of EUL aqueous extract administration, serum levels of SOD, CTA, calcium, and phosphorus were upregulated, whereas MDA levels were decreased (p <.01). The aqueous EUL extract also upregulated the expression of TRPV5, PMCA‐1b, and CaBP‐9 k in the kidney and small intestine of DOP mice (p <.01). Furthermore, the expression of Nrf2 and HO‐1 in the kidney, small intestine, and femur tissues was increased (p <.01). EUL aqueous extract reduced blood glucose levels in DOP mice and regulated oxidative stress through the Nrf2/HO‐1 pathway, thereby maintaining calcium homeostasis and ultimately improving bone quality. Our study suggested that EUL aqueous extract may be effective in the treatment of DOP. [ABSTRACT FROM AUTHOR]

Skeletal muscle fibers need to have mechanisms to decrease energy consumption during intense physical exercise to avoid devastatingly low ATP levels, with the formation of rigor cross bridges and defective ion pumping. These protective mechanisms inevitably lead to declining contractile function in response to intense exercise, characterizing fatigue. Through our work, we have gained insights into cellular and molecular mechanisms underlying the decline in contractile function during acute fatigue. Key mechanistic insights have been gained from studies performed on intact and skinned single muscle fibers and more recently from studies performed and single myosin molecules. Studies on intact single fibers revealed several mechanisms of impaired sarcoplasmic reticulum Ca2+ release and experiments on single myosin molecules provide direct evidence of how putative agents of fatigue impact myosin's ability to generate force and motion. We conclude that changes in metabolites due to an increased dependency on anaerobic metabolism (e.g., accumulation of inorganic phosphate ions and H+) act to directly and indirectly (via decreased Ca2+ activation) inhibit myosin's force and motion-generating capacity. These insights into the acute mechanisms of fatigue may help improve endurance training strategies and reveal potential targets for therapies to attenuate fatigue in chronic diseases. [ABSTRACT FROM AUTHOR]

Carbohydrates are the main macromolecule of poultry feed (40-70 %), categorized into digestible and indigestible forms. Poultry uses digestible carbohydrates to supply energy. Still, the indigestible part (water-soluble and nonsoluble) has different roles in anatomy, histology, water loss, bacterial microflora, mucosal health, normal secretions, feed transport time, and digestion rate in the gastrointestinal tract. Cereals (like corn), the carbohydrate source in poultry feed, can contain mycotoxins or water-soluble indigestible fibers; thus, some mycotoxin-free commercial products contain insoluble indigestible carbohydrates. In this study, the effect of micronized Lignocelluloses (Under trade name ARBOCEL®) was evaluated on calcium metabolism, eggshell quality, and performance of commercial Hy-Line W-36 layers. The results showed that the product had a good effect on the evaluated factors, but in some cases, there was not any significant effect that compared to other groups. However, it is better to evaluate the impact of using this product in various concentrations, ages, periods, heat-stress conditions, and digestive tract microflora disturbance, which is beyond the aim of this study and can be subject to subsequent researches. [ABSTRACT FROM AUTHOR]

Simple Summary: Vitamin D3 and vitamin K3 each play a crucial role in the growth, skeletal development, and regulation of bone biomarkers and calcium homeostasis in larval and juvenile gilthead seabream. Although their interaction has been shown to influence these parameters in animals and humans, there is limited research on this interaction in fish. In this study, juvenile gilthead seabream was fed diets with varying combinations of vitamin D3 and K3. The results showed no significant effects on growth, serum calcitriol levels, or morphometric parameters. However, a significant impact was observed on bone biomarkers and calcium-regulating genes across different tissues. Additionally, there was an increasing tendency of skeletal anomalies with higher vitamin levels. These findings suggest that, while dietary vitamin D3 and K3 can modulate bone biomarkers and calcium-regulating genes in fish, they do not significantly influence growth or serum calcitriol, likely due to the size and developmental stage of the fish. Based on this, we recommend considering vitamin D3 and K3 in diets to support skeletal health but note that they may not yield substantial changes in growth outcomes for juvenile gilthead seabream. The interaction between vitamin D and vitamin K is crucial for regulating bone metabolism and maintaining calcium homeostasis across diverse animal species due to their complementary roles in calcium metabolism and bone health. However, research on this interaction of vitamin D and K in fish, particularly Mediterranean species like gilthead seabream, is limited or not studied. This study aimed to understand the effects of different dietary combinations of vitamin D3 and K3 on juvenile gilthead seabream. Accordingly, seabream juveniles were fed with varying combinations of vitamin D3/vitamin K3 (mg/kg diet) for 3 months: (0.07/0.01), (0.20/0.58), (0.19/1.65), (0.51/0.74), (0.56/1.00). At the end of the trial, survival, growth, body morphology, serum calcitriol, and vertebral mineral composition remained unaffected by varying vitamin levels, while gene expression patterns related to bone formation, resorption, and calcium regulation in various tissues were significantly influenced by both vitamins and their interaction. Gilthead seabream juveniles fed the 0.07/0.01 mg/kg diet upregulated calcium-regulating genes in the gills, indicating an effort to enhance calcium absorption to compensate for dietary deficiencies. Conversely, an increase in vitamin D3 and K3 up to 0.19 and 1.65 mg/kg, respectively, upregulated bone formation, bone remodeling, and calcium homeostasis-related gene expression in vertebra and other tissues. On the contrary, a dietary increase in these vitamins up to 0.56 mg/kg vitamin D3 and 1.00 mg/kg vitamin K3 downregulated calcium metabolism-related genes in tissues, suggesting an adverse interaction resulting from elevated levels of these vitamins in the diet. Hence, sustaining an equilibrium in the dietary intake of vitamin D3 and vitamin K3, in an appropriately combined form, may potentially induce interactions between the vitamins, contributing to favorable effects on bone development and calcium regulation in gilthead seabream juveniles. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction is implicated in heat-induced skeletal muscle (SKM) injury and its underlying mechanisms remain unclear. Evidence suggests that cellular ions and molecules, including divalent cations and adenine nucleotides, are involved in the regulation of mitochondrial function. In this study, we examined Ca2+, Mg2+, and NAD+ levels in mouse C2C12 myoblasts and SKM in response to heat exposure. During heat exposure, mitochondrial Ca2+ levels increased significantly, whereas cytosolic Ca2+ levels remained unaltered. The mitochondrial Ca2+ levels in the SKM of heat-exposed mice were 28% higher compared to control mice. No changes in cytosolic Ca2+ were detected between the two groups. Following heat exposure, cytosolic and mitochondrial Mg2+ levels were reduced by 47% and 23% in C2C12 myoblasts, and by 51% and 44% in mouse SKMs, respectively. In addition, heat exposure decreased mitochondrial NAD+ levels by 32% and 26% in C2C12 myoblasts and mouse SKMs, respectively. Treatment with the NAD+ precursor nicotinamide riboside (NR) partially prevented heat-induced depletion of NAD+. Additionally, NR significantly reduced heat-increased mitochondrial fission, mitochondrial depolarization, and apoptosis in C2C12 myoblasts and mouse SKMs. No effects of NR on heat-induced changes in intracellular Ca2+ and Mg2+ levels were observed. This study provides in vitro and in vivo evidence that acute heat stress causes alterations in mitochondrial Ca2+, Mg2+, and NAD+ homeostasis. Our results suggest mitochondrial NAD+ homeostasis as a therapeutic target for the prevention of heat-induced SKM injury. [ABSTRACT FROM AUTHOR]

Melatonin, a product of tryptophan metabolism via serotonin, is a molecule with an indole backbone that is widely produced by bacteria, unicellular eukaryotic organisms, plants, fungi and all animal taxa. Aside from its role in the regulation of circadian rhythms, it has diverse biological actions including regulation of cytoprotective responses and other functions crucial for survival across different species. The latter properties are also shared by its metabolites including kynuric products generated by reactive oxygen species or phototransfomation induced by ultraviolet radiation. Vitamins D and related photoproducts originate from phototransformation of ∆5,7 sterols, of which 7‐dehydrocholesterol and ergosterol are examples. Their ∆5,7 bonds in the B ring absorb solar ultraviolet radiation [290–315 nm, ultraviolet B (UVB) radiation] resulting in B ring opening to produce previtamin D, also referred to as a secosteroid. Once formed, previtamin D can either undergo thermal‐induced isomerization to vitamin D or absorb UVB radiation to be transformed into photoproducts including lumisterol and tachysterol. Vitamin D, as well as the previtamin D photoproducts lumisterol and tachysterol, are hydroxylated by cyochrome P450 (CYP) enzymes to produce biologically active hydroxyderivatives. The best known of these is 1,25‐dihydroxyvitamin D (1,25(OH)2D) for which the major function in vertebrates is regulation of calcium and phosphorus metabolism. Herein we review data on melatonin production and metabolism and discuss their functions in insects. We discuss production of previtamin D and vitamin D, and their photoproducts in fungi, plants and insects, as well as mechanisms for their enzymatic activation and suggest possible biological functions for them in these groups of organisms. For the detection of these secosteroids and their precursors and photoderivatives, as well as melatonin metabolites, we focus on honey produced by bees and on body extracts of Drosophila melanogaster. Common biological functions for melatonin derivatives and secosteroids such as cytoprotective and photoprotective actions in insects are discussed. We provide hypotheses for the photoproduction of other secosteroids and of kynuric metabolites of melatonin, based on the known photobiology of ∆5,7 sterols and of the indole ring, respectively. We also offer possible mechanisms of actions for these unique molecules and summarise differences and similarities of melatoninergic and secosteroidogenic pathways in diverse organisms including insects. [ABSTRACT FROM AUTHOR]

Vitamin D is a hormone-like vitamin that plays a primary physiological role in regulating calcium metabolism. In addition to endogenous synthesis through sunlight exposure, dietary supplementation with vitamin D is indispensable for maintaining optimal vitamin D levels. To ensure precision and efficacy in quantifying daily vitamin D intake among the Japanese people, we established a method to measure vitamin D in food. This method optimizes instrument costs and streamlines cumbersome processes. Initially, thin-layer chromatography (TLC) was used to separate vitamin D from food samples, followed by a quantitative analysis using gas chromatography-mass spectrometry (GC-MS) with deuterated vitamin D as an internal standard. Despite the elevated temperature conditions of GC-MS, which lead to the generation of thermal decomposition compounds, the method remains accurate and effective, with an limit of quantitation (LOQ) as low as 0.8 ng for vitamin D. Subsequently, we applied this method to quantify the vitamin D content in 120 meal samples. The meals, designed by a registered dietitian (RD), were served in the dormitory and cafeteria of a Japanese company. The total vitamin D content {mean ± standard deviation (SD)} was 14.7 ± 13.7 µg/day. The measured total vitamin D content in the meal samples, showing a congruent range of 15.7 ± 12.6 µg/day, closely aligned with the corresponding estimate derived from Excel Eiyou-kun. In summary, this study established a method using GC-MS to simultaneously measure vitamin D2 and D3 in meals, which may be suitable for analyzing food samples for their vitamin D content in large quantities. [ABSTRACT FROM AUTHOR]

Background: Variants in SLC34A1 and SLC34A2 genes, which encode co-transporters NaPi2a and NaPi2c, respectively, can lead to hypophosphatemia due to renal phosphate loss. This condition results in hypercalcitriolemia and hypercalciuria, leading to formation of kidney stones and nephrocalcinosis. Phenotype is highly variable. Management includes hyperhydration, dietary modifications, and/or phosphate supplementation. Thiazides and azoles may be used, but randomized studies are needed to confirm their clinical efficacy. Methods: We conducted a retrospective study in the pediatric nephrology unit at Grenoble University Hospital from January 2010 to December 2023. The study aimed to describe clinical and biological symptoms of patients with confirmed SLC34A1 and SLC34A3 gene variants and their outcomes. Results: A total of 11 patients (9 females) from 6 different families had variants in the SLC34A1 (5 patients) and SLC34A3 (6 patients) genes. Median age at diagnosis was 72 [1–108] months. Average follow-up duration was 8.1 ± 4.5 years. Presenting symptom was nephrocalcinosis (4 cases), followed by renal colic (3 cases). At diagnosis, 90% of patients had hypercalciuria and 45% had hypercalcitriolemia. Management included hyperhydration and dietary advice. All patients showed favorable outcomes with normal growth and school attendance. One patient with an SLC34A3 variant showed regression of nephrocalcinosis. Kidney function remained normal. Conclusion: Clinical and biological manifestations of SLC34 gene variants are highly variable, even among siblings; therefore, management must be personalized. Hygienic and dietary measures (such as hyperhydration, a low sodium diet, and age-appropriate calcium intake) result in favorable outcomes in most cases. Use of azoles (e.g., fluconazole) appears to be a promising therapeutic option. [ABSTRACT FROM AUTHOR]

Acute cartilage injuries, such as intra-articular fractures and blunt impacts, frequently result in chondrocyte death and extracellular matrix (ECM) degradation, significantly elevating the risk of post-traumatic osteoarthritis (PTOA). Despite advances in treatment, no effective therapies currently exist to fully cure PTOA or halt its progression. This study explores the protective effects of the dietary fatty acid eicosapentaenoic acid (EPA) on human primary chondrocytes (HPCs) and cartilage explants exposed to mechanical overload and blunt trauma. HPCs were isolated and subjected to mechanical stretching using BioFlex six-well culture plates, while cartilage explants were subjected to impact loading via a customized drop tower. EPA was incorporated into the culture medium, followed by assays to evaluate cell viability, calcium (Ca²⁺) influx, apoptosis, reactive oxygen species (ROS) levels, and collagen type II alpha (Col-2a) expression. EPA treatment markedly decreased chondrocyte mechanical sensitivity, as demonstrated by enhanced cell viability and reduced lactate dehydrogenase (LDH) release. Furthermore, EPA inhibited Piezo1 activation, leading to lower intracellular Ca²⁺ concentrations, decreased apoptosis, and diminished ROS levels. In cartilage explants, EPA improved chondrocyte viability, minimized structural damage, and sustained higher Col-2a expression compared to the blunt trauma group. These results indicate that EPA effectively shields chondrocytes and cartilage explants from mechanical overload-induced damage by inhibiting Piezo1 activation and mitigating Ca²⁺ influx, apoptosis, and oxidative stress. The findings suggest that EPA supplementation could offer a promising strategy for preventing PTOA progression following acute cartilage injuries. Further research is warranted to assess the clinical applications of EPA and confirm its efficacy in larger animal models and human trials. [ABSTRACT FROM AUTHOR]

Calcium metabolism dysregulation in the setting of primary hyperparathyroidism (PHPT) mediated chondrocalcinosis is implicated in joint pain, a key element in the decision regarding arthroplasty for osteoarthritis. The relationship between hypercalcemia and joint pain, before and after arthroplasty, is unknown. This study investigates the association between preoperative hypercalcemia and postoperative outcomes following total knee (TKA) and total hip arthroplasty (THA). A retrospective chart review was conducted on patients who underwent initial elective THA or TKA. Patients with a preoperative serum calcium >10.2 mg/dL were matched (1:2-1:4) with nearest neighbor to patients with normal serum calcium. THA and TKA functional outcomes were measured at baseline and 1-y postoperatively using patient-reported Hip Disability and Osteoarthritis Outcome Scores and Knee Injury and Osteoarthritis Outcome Scores surveys. Postoperative complications, readmissions, length of stay, and functional outcome scores were compared. Four hundred ninety-five patients (106 hypercalcemic cases, 389 matched controls) were included. Of these, 223 patients underwent THA (46 cases; 177 controls) and 272 patients underwent TKA (61 cases; 211 controls). There were no differences in Hip Disability and Osteoarthritis Outcome Scores and Knee Injury and Osteoarthritis Outcome Scores scores, postoperative complications, readmissions, or length of stay between cases and controls. Only 19/106 (18%) hypercalcemic patients had a parathyroid hormone (PTH); of these, 9 (47%) had possible PHPT (PTH > 40). Patients with hypercalcemia undergoing arthroplasty have similar functional and postoperative outcomes as normocalcemic patients. As PTH was obtained in <20% of hypercalcemic cases and 50% had possible PHPT, we recommend that hypercalcemic patients undergo PHPT workup. Additional investigation is needed to determine the effect of PHPT on arthroplasty outcomes. [ABSTRACT FROM AUTHOR]

Purpose: This aim of this study was to assess the possible association between diurnal oscillations and biochemical markers associated with calcium homeostasis. This included the markers parathyroid hormone (PTH), total calcium, total alkaline phosphatase, phosphate, and 25-hydroxyvitamin D (25-OH-D). By examining the influence of circadian rhythms on these parameters, the study aimed to deepen the understanding of calcium metabolism dynamics and its clinical implications. Patients and methods: Blood samples from 24 Caucasian male volunteers aged 20 to 40 (mean age 26) with normal pulse, blood pressure, and BMI were analyzed for biochemical markers related to calcium homeostasis. Data was obtained from the Bispebjerg study of diurnal variations. Blood samples were collected every three hours over a 24-hour period. Patients were fasting from 22:00 to 09:00. The participants spent 24 h in the hospital ward, receiving regular meals and engaging in low-intensity activities. They experienced 15 h of daylight and 9 h of complete darkness during sleep. Diurnal oscillations were analyzed using cosinor analysis with statistical significance set at p < 0.05. Results: Total calcium, phosphate, and PTH exhibited significant diurnal variations. Total calcium and PTH were inversely synchronized while PTH and phosphate oscillated in synchronization. The three parameters showed relatively large amplitude/reference range ratios from 25.4% to 41.5%. Conclusion: This study found notable fluctuations in total calcium, phosphate, and PTH levels over a 24-hour cycle, while 25-OH-D and total alkaline phosphatase remained consistent. It highlights the importance of considering sampling times for total calcium, PTH, and phosphate in clinical settings. [ABSTRACT FROM AUTHOR]

Calcium stress can negatively impact plant growth, prompting plants to respond by mitigating this effect. However, the specific mechanisms underlying this response remain unclear. In this study, we used non-targeted metabolomics and transcriptomics to investigate the response mechanisms of Zelkova schneideriana leaves under varying degrees of calcium stress. Results revealed that calcium stress led to wilt in young leaves. When calcium stress exceeds the tolerance threshold of the leaf, it results in wilting of mature leaves, rupture of chloroplasts in palisade tissue, and extensive wrinkling and breakage of leaf cells. Transcriptomic analysis indicated that calcium stress inhibited photosynthesis by suppressing the expression of genes related to photosynthetic system II and electron transport. Leaf cells activate phenylpropanoid biosynthesis, flavonoid biosynthesis, and Vitamin B6 metabolism to resist calcium stress. When calcium accumulation gradually surpassed the tolerance threshold of the cells, this results in failure of conventional anti-calcium stress mechanisms, leading to cell death. Furthermore, excessive calcium stress inhibits the expression of CNGC and anti-pathogen genes. The results of the metabolomics study showed that five key metabolites increased in response to calcium stress, which may play an important role in countering calcium stress. This study provides insights into the response of Z. schneideriana leaves to different levels of calcium stress, which could provide a theoretical basis for cultivating Z. schneideriana in karst areas and enhance our understanding of plant responses to calcium stress. [ABSTRACT FROM AUTHOR]

Calcium is a fundamental and integrative element and helps to ensure optimal health by regulating various physiological and pathological processes. While there is substantiated evidence confirming the beneficial effects of calcium in the treatment, management, and prevention of various health conditions, including cancer, conflicting studies are imperative to acknowledge the potential negative role of calcium supplementation. The studies on calcium supplementation showed that a specific dose can help in the maintenance of good human health, and in the control of different types of diseases, including cancer. Calcium alone and when combined with vitamin D, emerges as a promising therapeutic option for efficiently managing cancer growth, when used with chemotherapy. Combination therapy is considered a more effective approach for treating advanced types of colorectal cancer. Nevertheless, several challenges drastically influence the treatment of cancer, such as individual discrepancy, drug resistance, and stage of cancer, among others. Henceforth, novel preventive, reliable therapeutic modalities are essential to control and reduce the incidence and mortality of colorectal cancer (CRC). The calcium-sensing receptor (CaSR) plays a pivotal role in calcium homeostasis, metabolism, and regulation of oncogenesis. Numerous studies have underscored the potential of CaSR, a G protein-coupled receptor, as a potential biomarker and target for colorectal cancer prevention and treatment. The multifaceted involvement of CaSR in anti-inflammatory and anti-carcinogenic processes paves the way for its utilization in the diagnosis and management of colorectal cancer. The current review highlights the important role of supplemental calcium in overall health and disease, along with the exploration of intricate mechanisms of CaSR pathways in the management and prevention of colorectal cancer. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a dangerous heavy metal that is non-degradable in the environment. Many organs can accumulate Cd and adversely affect organ function and health. Cd is considered as a teratogenic and embryotoxic agent. This study aims to evaluate the teratogenicity of Cd at concentrations lesser than the permissible and its effects on the heart during chick embryogenesis. Fertilized eggs of the chick Gallus domesticus were divided into; control, saline injected and four experimental groups injected with single doses of 5, 25, 50 or 75 µM of CdCl2. Histological observations of the heart before hatching and the cardiomyocytes after hatching were recorded. Morphometric measurements of heart chambers were achieved at 3, 4 and 6 days of incubation. Electrocardiograph and respiratory rate were recorded at tenth day. Different cardiac problems had been brought on by Cd. In comparison to controls, the heart looked much larger, and in certain cases, growth retardation was seen. Degeneration in heart walls and malformations of dorsal aorta were noticed. Morphometrically, the width and wall thickness of heart chambers showed significant changes. Heart beats and respiratory rate significantly decreased compared to control. The cardiotoxic effect of Cd on heart compartments structure and function was dose dependent. One of Cd toxicity is its ability to induce cellular oxidative stress. The heart in particular is sensitive to oxidative stress. Cardiac oxidative stress might intensify heart failure and promote disease progression. Calcium is one of the components that is needed for normal heart work. Cd might interfere with calcium metabolism by removing it from the body. [ABSTRACT FROM AUTHOR]

Dysferlin is a multi‐functional protein that regulates membrane resealing, calcium homeostasis, and lipid metabolism in skeletal muscle. Genetic loss of dysferlin results in limb girdle muscular dystrophy 2B/2R (LGMD2B/2R) and other dysferlinopathies – rare untreatable muscle diseases that lead to permanent loss of ambulation in humans. The mild disease severity in dysferlin‐deficient mice and diverse genotype‐phenotype relationships in LGMD2B patients have prompted the development of new in vitro models for personalized studies of dysferlinopathy. Here the first 3‐D tissue‐engineered hiPSC‐derived skeletal muscle ("myobundle") model of LGMD2B is described that exhibits compromised contractile function, calcium‐handling, and membrane repair, and transcriptomic changes indicative of impaired oxidative metabolism and mitochondrial dysfunction. In response to the fatty acid (FA) challenge, LGMD2B myobundles display mitochondrial deficits and intracellular lipid droplet (LD) accumulation. Treatment with the ryanodine receptor (RyR) inhibitor dantrolene or the dissociative glucocorticoid vamorolone restores LGMD2B contractility, improves membrane repair, and reduces LD accumulation. Lastly, it is demonstrated that chemically induced chronic RyR leak in healthy myobundles phenocopies LGMD2B contractile and metabolic deficit, but not the loss of membrane repair capacity. Together, these results implicate intramyocellular Ca2+ leak as a critical driver of dysferlinopathic phenotype and validate the myobundle system as a platform to study LGMD2B pathogenesis. [ABSTRACT FROM AUTHOR]

Osteoporosis, a systemic skeletal disorder marked by diminished bone mass and compromised bone microarchitecture, is becoming increasingly prevalent due to an aging population. The underlying pathophysiology of osteoporosis is attributed to an imbalance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Osteoclasts play a crucial role in the development of osteoporosis through various molecular pathways, including the RANK/RANKL/OPG signaling axis, cytokines, and integrins. Notably, the calcium signaling pathway is pivotal in regulating osteoclast activation and function, influencing bone resorption activity. Disruption in calcium signaling can lead to increased osteoclast-mediated bone resorption, contributing to the progression of osteoporosis. Emerging research indicates that calciumpermeable channels on the cellular membrane play a critical role in bone metabolism by modulating these intracellular calcium pathways. Here, we provide an overview of current literature on the regulation of plasma membrane calcium channels in relation to bone metabolism with particular emphasis on their dysregulation during the progression of osteoporosis. Targeting these calcium channels may represent a potential therapeutic strategy for treating osteoporosis. [ABSTRACT FROM AUTHOR]

Simple Summary: Sorcin is a protein that helps cells handle calcium. It is often found in high amounts in cancer cells, especially those that are resistant to treatment. Sorcin plays a key role in cancer growth and spread by helping cancer cells avoid the toxic effects of chemotherapy drugs, acting on multiple cellular mechanisms. This review will explore sorcin's structure and function, its role in cancer, and how we might be able to target it for new treatments. SOluble Resistance-related Calcium-binding proteIN (sorcin) earned its name due to its co-amplification with ABCB1 in multidrug-resistant cells. Initially thought to be an accidental consequence of this co-amplification, recent research indicates that sorcin plays a more active role as an oncoprotein, significantly impacting multidrug resistance (MDR). Sorcin is a highly expressed calcium-binding protein, often overproduced in human tumors and multidrug-resistant cancers, and is a promising novel MDR marker. In tumors, sorcin levels inversely correlate with both patient response to chemotherapy and overall prognosis. Multidrug-resistant cell lines consistently exhibit higher sorcin expression compared to their parental counterparts. Furthermore, sorcin overexpression via gene transfection enhances drug resistance to various chemotherapeutic drugs across numerous cancer lines. Conversely, silencing sorcin expression reverses drug resistance in many cell lines. Sorcin participates in several mechanisms of MDR, including drug efflux, drug sequestering, cell death inhibition, gene amplification, epithelial-to-mesenchymal transition, angiogenesis, and metastasis. The present review focuses on the structure and function of sorcin, on sorcin's role in cancer and drug resistance, and on the approaches aimed at targeting sorcin. [ABSTRACT FROM AUTHOR]

Background: In the realm of swine production, optimizing body composition and reducing excessive fat accumulation is critical for enhancing both economic efficiency and meat quality. Despite the acknowledged impact of dietary calcium (Ca) and phosphorus (P) on lipid metabolism, the precise mechanisms behind their synergistic effects on fat metabolism remain elusive. Results: Research observations have shown a decreasing trend in the percentage of crude fat in carcasses with increased calcium and phosphorus content in feed. Concurrently, serum glucose concentrations significantly decreased, though differences in other lipid metabolism-related indicators were not significant across groups. Under conditions of low calcium and phosphorus, there is a significant suppression in the expression of FABPs, CD36 and PPARγ in the jejunum and ileum, leading to inhibited intestinal lipid absorption. Concurrently, this results in a marked increase in lipid accumulation in the liver. Conversely, higher levels of dietary calcium and phosphorus promoted intestinal lipid absorption and reduced liver lipid accumulation, with these changes being facilitated through the activation of the CAMKK2/AMPK signaling pathway by high-calcium-phosphorus diets. Additionally, the levels of calcium and phosphorus in the diet significantly altered the composition of liver lipids and the gut microbiota, increasing α-diversity and affecting the abundance of specific bacterial families related to lipid metabolism. Conclusion: The evidence we provide indicates that the levels of calcium and phosphorus in the diet alter body fat content and lipid metabolism by modulating the response of the gut-liver axis to lipids. These effects are closely associated with the activation of the CAMKK2/AMPK signaling pathway. [ABSTRACT FROM AUTHOR]

Background: Vitamin D is usually consider as an important prohormone, which regulated the metabolism of calcium, phosphate and bone physiology. Serum uric acid (SUA) is the end product of purine metabolism in humans and uric acid is an independent risk factor for insulin resistance, cardiovascular disease (CVD), non-alcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus, metabolic syndrome and atherosclerosis syndrome. However, the relationship between serum uric acid (SUA) and 25 (OH) D is still unclear in our population based study. Methods: The cross sectional study was conducted in department of biochemistry of Malda Medical College and Hospital, 100 consecutive patients were enrolled over a period six months after obtaining institutional ethical clearance. Serum Vitamin D level was analyzed by Siemens ADVIA centaur, standardized against ID-LC/MS/MS, as per vitamin D standardization. Serum uric acid was estimated by Uricase method. Results: The level of 25 (OH) D was higher in hyperuricemic than in normouricemic female and male subjects (t value=-8.4, p value =<0.001 & t value=-4.6, p value= <0.001. Furthermore, 25(OH) D was positively correlated with serum uric acid, (correlation coefficient 7.3 p value= <0.001) Conclusions: Our findings revealed that serum uric acid was positively associated with 25 (OH) D, higher levels of serum 25 (OH) D may be a potential predictor of hyperuricemia. [ABSTRACT FROM AUTHOR]

To survive daily damage, the formation of actomyosin ring at the wound edge is required to rapidly close cell wounds. Calcium influx is one of the start signals for these cell wound repair events. Here, we find that the rapid recruitment of all 3 Drosophila calcium-responding and phospholipid-binding Annexin proteins (AnxB9, AnxB10, and AnxB11) to distinct regions around the wound is regulated by the quantity of calcium influx rather than their binding to specific phospholipids. The distinct recruitment patterns of these Annexins regulate the subsequent recruitment of RhoGEF2 and RhoGEF3 through actin stabilization to form a robust actomyosin ring. Surprisingly, while the wound does not close in the absence of calcium influx, we find that reduced calcium influx can still initiate repair processes, albeit leading to severe repair phenotypes. Thus, our results suggest that, in addition to initiating repair events, the quantity of calcium influx is important for precise Annexin spatiotemporal protein recruitment to cell wounds and efficient wound repair. [ABSTRACT FROM AUTHOR]

Organophosphorus pesticide poisoning can lead to severe brain damage, but the specific mechanisms involved are not fully understood. Our research aims to elucidate the function of the TRPV4 ion channel in the development of brain injury induced by paraoxon (POX). In vivo, we examined the survival rate, behavioral seizures, histopathological alterations, NMDA receptor phosphorylation, as well as the expression of the NLRP3-ASC-caspase-1 complex and downstream inflammatory factors in the POX poisoning model following intervention with the TRPV4 antagonist GSK2193874. In vitro, we investigated the effects of GSK2193874 on NMDA-induced inward current, cell viability, cell death rate, and Ca2+ accumulation in primary hippocampal neurons. The treatment with the TRPV4 antagonist increased the survival rate, suppressed the status epilepticus, improved pathological damage, and reduced the phosphorylation level of NMDA receptors after POX exposure. Additionally, it inhibited the upregulation of NLRP3 inflammasome and inflammatory cytokines expression after POX exposure. Moreover, the TRPV4 antagonist corrected the NMDA-induced increase in inward current and cell death rate, decrease in cell viability, and Ca2+ accumulation. TRPV4 participates in the mechanisms of brain injury induced by POX exposure through NMDA-mediated excitotoxicity and NLRP3-mediated inflammatory response. [ABSTRACT FROM AUTHOR]

Diets containing inorganic phosphate additives are unbalanced with respect to calcium and these diets have been linked to the development of altered bone metabolism. Using 2 randomized cross-over studies in healthy humans, we (1) characterized the hormonal and urinary response to 2 meals with the same reported phosphorus amount (562–572 mg), where one was manufactured with inorganic phosphate additives and a comparatively lower Ca:P molar ratio (0.26 vs 0.48), and (2) assessed how acute homeostatic mechanisms adapt following 5-d exposure to recommended dietary phosphorus amount (~700 mg P/d) compared to a diet enriched with inorganic phosphate additives (~1100 mg P/d). Participants were then challenged with 500 mg of oral phosphorus in the form of inorganic phosphate after an overnight fast following each diet condition. Measurements included serum calcium, phosphate, PTH, and fibroblast growth factor 23 , vitamin D metabolites, and urine calcium and phosphate excretion. Following the meal containing inorganic phosphate additives with a low Ca:P ratio, serum phosphate was higher and more phosphate was excreted in the urine compared to the low additive meal. Although the Ca:P and calcium content was lower in the high additive meal, the same amount of calcium was excreted into the urine. Subsequently, increasing only dietary phosphate through additives resulted in lower 24-h excretion of calcium. The oral phosphate challenge promoted urinary calcium excretion, despite no consumption of calcium, which was attenuated when pre-acclimated to a high phosphate diet. These data suggest that ingestion of inorganic phosphate promotes calcium excretion, but homeostatic mechanisms may exist to reduce calcium excretion that are responsive to dietary intake of phosphate. Future studies are required to evaluate potential implication of diets enriched with inorganic phosphate additives on bone health. Lay Summary: Excessive dietary phosphorus has been linked to the development of bone and vascular disorders. Further, highly bioavailable inorganic phosphate additives, which are unregulated, have been estimated to comprise approximately 50% of an individual's consumed dietary phosphorus. Using 2 randomized cross-over studies in young healthy participants, we assessed (1) the hormonal and urinary response to 2 meals with the same reported phosphate amount, but one manufactured with inorganic phosphate additives, and (2) how acute homeostatic mechanisms adapt following 5-d of a diet supplemented with inorganic phosphate additives. The results suggest that ingestion of meals containing phosphate additives promotes excess calcium excretion, but homeostatic mechanisms in young healthy adults are sufficient to reduce calcium excretion in response to a 5-d dietary intake of these phosphate additives. These findings indicate an important role of inorganic phosphate additives on acute and chronic calcium homeostasis that will need to be carefully explored for potential implications on bone and/or vascular outcomes. Together these findings also indicate the critical importance of bioavailability of phosphate and the balance with calcium in dietary management. Graphical Abstract [ABSTRACT FROM AUTHOR]

Purpose: Pathogenesis of sacral fragility fractures is not fully understood. This study investigates zonal distribution of calcium salt and fat marrow in intact bone-healthy and osteoporotic pelvis. In addition, in unilateral sacral fractures, the fracture side was compared with the intact side. Methods: CT and MRI images of 37 pelves were analyzed. Zonal calcium salt distribution by Hounsfield units (HU) was recorded for each CT dataset. Fat marrow content was measured in MRI mDixon–Quant sequence. The cohort was divided: intact pelves with (PEO, HU < 100, n = 8) and without osteoporosis (PE, HU ≥ 100, n = 14) based on the mean HU value in LWK5. A third group consisted of patients with osteoporosis and unilateral fractures (PEOFx, n = 10). Conclusion: The results suggest that in PEO sacral alae experience disproportionate skeletal rarefaction. This concerns the sacral ala at the S1 level (− 25 ± 55), whereby the calcium salt content is so low that it corresponds to the S3 level of healthy bone (− 20 ± 21 HU). This explains the occurrence of transalar fractures in the load-transmitting zone S1. In PEOFx, the calcium salt density was higher and the fat content was lower on the fractured side than on the intact side, indicating bony compacting due to lateral compression and fat displacement due to hematoma in the accident mechanism. This study makes an important contribution to the understanding of the development of sacral fragility fractures. Furthermore, impaction of the cancellous bone within the fracture can be demonstrated. [ABSTRACT FROM AUTHOR]

Bacterial chondronecrosis with osteomyelitis (BCO) lameness is a major welfare issue for broiler production worldwide affecting approximately 1.5% of broilers over 42 days old. Excessive body weight gain causes mechanical stress on long bones, leading to micro-fractures. This condition induces a bacterial infection of fractures, resulting in bone necrosis and eventual BCO lameness. Increasing gut integrity and supporting Calcium metabolism contribute to the optimal bone structure and subsequently reduce BCO lameness. Probiotics thus provide an excellent strategy for alleviating BCO due to the improvement of intestinal integrity and barrier function. Accordingly, the present study investigated the lameness reduction through the feed supplementation of a selected probiotic. Broiler chickens were assigned to three treatments, including a control litter group (FL), a PoultryStar®Bro probiotic fed group (BRO), and a control wire-flooring group (CW) designed to induce BCO lameness. The probiotic significantly decreased lameness by 46% compared to the control group (p < 0.05). The most predominant bacteria identified from the BCO lesions were Staphylococcus cohnii and Staphylococcus lentus. Moreover, significant increments of tight junction gene expression in jejunum and ileum, plus numerical improvements of body weight gain (BW; +360 g) and feed conversion ratio (FCR; −12 pts) were observed in BRO-supplemented birds. [ABSTRACT FROM AUTHOR]

For prosthodontic operations to be successful, particularly those involving dental implants and the preservation of alveolar bone, adequate calcium levels are necessary. In order to prevent excessive ridge resorption and maintain the stability and effectiveness of dental prostheses, it is imperative to maintain adequate quantities of calcium through diet or supplementation. It is essential for healthy blood clotting, maintaining strong bones, facilitating normal muscle and nerve function, and supporting the strength and shape of teeth. [ABSTRACT FROM AUTHOR]

Evidence is increasing that vitamin D and CYP11A1-derived vitamin D, tachysterol, and lumisterol metabolites play a significant antioxidant role beyond its classical functions in bone health and calcium metabolism. Several recent studies have linked these elements to reduced oxidative stress as well as improved immune, cardiovascular, and neurological functions as a result of chronic kidney disease and cancer. Additionally, supplementation with this vitamin has been shown to be one of the most cost-effective micronutrient interventions worldwide, highlighting its potential as a therapeutic approach. The underlying mechanisms and implications of this antioxidant function of vitamin D or CYP11A1-derived vitamin D, tachysterol, and lumisterol metabolites are not well understood. This comprehensive and narrative review is aimed at summarizing the current evidence regarding the molecular mechanisms implicated in this antioxidant function of vitamin D, as well as to provide a general overview and to identify key research areas for the future, offering an extensive perspective that can guide both researchers and clinicians in the management of diseases associated with oxidative stress and/or insufficient vitamin D status. [ABSTRACT FROM AUTHOR]

Rickets results from defective bone mineralization, leading to skeletal deformities. Among those deformities, rickets has been associated with craniosynostosis, the premature closure of cranial sutures. Most of these patients have fusion of major sutures. Rarely, squamosal craniosynostosis in association with rickets has been described. Squamosal craniosynostosis is noted as lacking a definitive head abnormality and difficult visualization on standard imaging modalities, leading to poor recognition. Careful attention should be given to rickets patients to monitor for these unusual suture closures. Additionally, craniosynostosis could be a presenting feature of rickets, and further rickets evaluation of the patient is indicated. [ABSTRACT FROM AUTHOR]

Vitamin D plays a critical role in many physiological functions, including calcium metabolism and musculoskeletal health. This commentary aims to explore the intricate relationships among skin complexion, race, and 25-hydroxyvitamin D (25[OH]D) levels, focusing on challenges the Endocrine Society encountered during clinical practice guideline development. Given that increased melanin content reduces 25(OH)D production in the skin in response to UV light, the guideline development panel addressed the potential role for 25(OH)D screening in individuals with dark skin complexion. The panel discovered that no randomized clinical trials have directly assessed vitamin D related patient-important outcomes based on participants' skin pigmentation, although race and ethnicity often served as presumed proxies for skin pigmentation in the literature. In their deliberations, guideline panel members and selected Endocrine Society leaders underscored the critical need to distinguish between skin pigmentation as a biological variable and race and ethnicity as socially determined constructs. This differentiation is vital to maximize scientific rigor and, thus, the validity of resulting recommendations. Lessons learned from the guideline development process emphasize the necessity of clarity when incorporating race and ethnicity into clinical guidelines. Such clarity is an essential step toward improving health outcomes and ensuring equitable healthcare practices. [ABSTRACT FROM AUTHOR]

Objective: Intra‐articular (IA) mineralization may contribute to osteoarthritis (OA) structural progression. We studied the association of IA mineralization on knee computed tomography (CT) with cartilage damage worsening on knee magnetic resonance imaging (MRI), with a focus on location‐ and tissue‐specific effects. Methods: Participants from the Multicenter Osteoarthritis Study with knee CT and MRI scans were included. Presence of IA mineralization on CT was defined as a Boston University Calcium Knee Score >0 anywhere in the knee. Cartilage worsening on MRI was defined as any increase in the MRI OA Knee Score, including incident damage. We evaluated the association of whole‐knee, compartment‐specific (ie, medial or lateral), and subregion‐specific (ie, location‐matched) IA mineralization at baseline with cartilage worsening at two years' follow‐up in the corresponding locations using binomial regression with generalized estimating equations, adjusting for age, sex, and body mass index (BMI). Results: We included 1,673 participants (mean age 60 years, 56% female, mean BMI 29). Nine percent had any IA mineralization in the knee, and 47.4% had any cartilage worsening on follow‐up. Mineralization of any tissue in the knee, regardless of location, was not associated with MRI cartilage worsening. However, cartilage mineralization was associated with 1.39 (95% confidence interval 1.04–1.88) times higher risk of cartilage worsening in the same compartment, with similar results in subregion‐specific analysis. Conclusion: CT‐detected IA mineralization in the cartilage was associated with higher risk of MRI cartilage worsening in the same compartment and subregion over two years. These findings suggest potential localized, tissue‐specific effects of IA mineralization on cartilage pathology in knee OA. [ABSTRACT FROM AUTHOR]

The periparturient period is characterized by the increased demand for calcium (Ca) in dairy cows. This has resulted in the use of several different prepartal nutritional strategies to prevent hypocalcemia postpartum. The objective of our study was to determine the effects of feeding synthetic zeolite A (XZ), a diet with negative dietary cation-anion difference (−DCAD), or a positive-DCAD diet (CON) during the close-up period on peripartal mineral dynamics and hormones involved in calcium metabolism. To this end, 121 multiparous Holstein cows, blocked by lactation number and expected due date, were enrolled at 254 d of gestation and randomly assigned to 1 of 3 prepartum diets: CON (+190 mEq/kg; n = 40), −DCAD (−65 mEq/kg; n = 41), or a diet supplemented with sodium aluminum silicate (XZ; +278 mEq/kg, fed at 3.3% DM, targeting 500 g/d; n = 40; Protekta Inc.). Blood, urine, and saliva samples were collected from enrollment until parturition, with data analyzed and presented beginning 14 d before parturition (d −14) until parturition (d 0), and on d 1, 2, 3, 6, 9, 12, 15, 18, 21, 35, and 49 postpartum, to assess mineral and hormone dynamics. Total fecal collections were performed in a subset of 8 cows per treatment group to assess fecal mineral loss. Data were analyzed as a randomized complete block design in SAS. Cows fed XZ and −DCAD had higher blood Ca concentrations compared with CON-fed cows, with XZ-fed cows exhibiting the highest blood Ca concentrations pre- and postpartum. Cows fed XZ had decreased blood and salivary phosphorus (P), increased fecal water-extractable phosphate, and the highest blood calcium concentrations pre- and postpartum. Parathyroid hormone was unaffected by diet but was increased at parturition in all treatments. Serotonin concentrations were increased in −DCAD and XZ cows compared with CON during the prepartum period. Our data indicate that the XZ group's improvement in blood Ca concentrations pre- and postpartum is most likely regulated by a dietary P restriction. Taken together, these data suggest that XZ and −DCAD diets improve postpartum calcium metabolism; however, they appear to work through different mechanisms. [ABSTRACT FROM AUTHOR]

In this review, we address the physiological aspects of the gonadotropin-releasing hormone (GnRH) effects on the immune organs, such as red bone marrow, thymus, spleen, and lymph nodes. The use of GnRH drugs leads to the replacement of red bone marrow with yellow one and an increase in the content of lymphoid and myeloid progenitor cells. These processes are paralleled by osteoporosis due to increased bone resorption with changes in calcium metabolism and a decrease in the density of various bone tissues, although there are opposing reports that GnRH has no effect on bone density and calcium metabolism. GnRH affects the thymus during both embryonic development and postnatal ontogenesis, in inflammation and age-related involution. Not only does GnRH cause changes in the thymus, but the thymus may in turn influence the GnRH system. Although a direct impact of GnRH on splenic cells has not been detected, splenic mass changed due to active immunization against GnRH in experiment. Unfortunately, very few articles demonstrate the physiological mechanisms of immunomodulation in such conditions. In any case, the obvious insufficiency and inconsistency of publications on each aspect of GnRH effects indicate that they are still poorly understood, and it is worth furthering not only applied but also fundamental studies in this direction, particularly in the context of developing effective systems for immune control. [ABSTRACT FROM AUTHOR]

Data on the effectiveness of denosumab on osteoporosis after kidney transplantation are limited. We investigated the long-term bone mineral density (BMD) changes in kidney transplant recipients (KTRs) treated with denosumab compared to untreated KTRs. We enrolled KTRs treated with denosumab 60 mg/6 months for 4 years. An untreated group of sex and age-matched KTRs with a 1:1 ratio was included. The primary outcome was BMD changes assessed by Dual-energy X-ray Absorptiometry over 4 years. Data on serum creatinine, alkaline phosphatase (ALP), parathyroid hormone, and 25-hydroxyvitamin D were collected. All patients received oral cholecalciferol and calcium supplementation. 23 denosumab-treated KTRs were enrolled, and 23 untreated KTRs. The median time from transplant to the start of denosumab was 4 years (range 0:24). The denosumab group showed a significant increase from baseline in BMD at the lumbar spine (LS) (9.0 ± 10.7%, p < 0.001), and total hip (TH) (3.8 ± 7.9%, p = 0.041). The untreated group showed a significant decrease at all sites (− 3.0 ± 7%, p = 0.041 at the LS; − 6.3 ± 9.2%, p = 0.003 at the TH; − 6.7 ± 9.3%, p = 0.003 at the FN). The between-group differences in percent BMD changes were statistically significant at all sites. Similar results were found for the respective Z-scores. The ALP serum levels significantly decreased from baseline only in the denosumab group, with a significant between-group difference (p = 0.032). No significant differences in serum creatinine, hypocalcaemic events or acute graft rejection rates were observed. Four years of denosumab therapy were associated with increased BMD in KTRs, while untreated KTRs showed significant BMD losses at all sites. [ABSTRACT FROM AUTHOR]

The addition of heat stress to resistance exercise or heated resistance exercise (HRE) is growing in popularity as emerging evidence indicates altered neuromuscular function and an amplification of several mechanistic targets of protein synthesis. Studies demonstrating increased protein synthesis activity have shown temperature-dependent mammalian target of rapamycin phosphorylation, supplemental calcium release, augmented heat shock protein expression, and altered immune and hormone activity. These intriguing observations have largely stemmed from myotube, isolated muscle fiber, or rodent models using passive heating alone or in combination with immobilization or injury models. A growing number of translational studies in humans show comparable results employing local tissue or whole-body heat with and without resistance exercise. While few, these translational studies are immensely valuable as they are most applicable to sport and exercise. As such, this brief narrative review aims to discuss evidence primarily from human HRE studies detailing the neuro)muscular, hormonal, and molecular responses to HRE and subsequent strength and hypertrophy adaptations. Much remains unknown in this exciting new area of inquiry from both a mechanistic and functional perspective warranting continued research. [ABSTRACT FROM AUTHOR]

BACKGROUND: During high sugar fermentation, yeast is mainly affected by high sugar stress in the early stage. It becomes jointly affected by high sugar and ethanol stress as ethanol accumulates during fermentation. Ca2+, as the second messenger of the cell, mediates various metabolic processes. In this study, the effects of the Ca2+ signal on the activities of key enzymes, expression of related genes of ethanol metabolism, and mitochondrial function were investigated. RESULTS: The results showed a significant increase in the activities of enzymes related to ethanol metabolism in yeast cells under a high sugar environment. Ca2+ significantly promoted the activities of enzymes related to mitochondrial respiratory metabolism and regulated the carbon flow between ethanol metabolism and the tricarboxylic acid cycle. The high sugar environment affected the expression of genes related to carbon metabolism, while the addition of Ca2+ stabilized the expression of related genes. CONCLUSION: Ca2+ signal participated in ethanol and mitochondrial metabolism and regulated the key enzymes and related gene expression to enhance the resistance of yeast to stress during high sugar fermentation. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Cinacalcet is an oral calcimimetic that has potential to non‐invasively treat primary hyperparathyroidism in dogs (Canis lupis familiaris). There is minimal data assessing its efficacy in dogs. This study aimed to determine whether a single dose of cinacalcet decreases serum ionized calcium (iCa), total calcium (tCa), and parathyroid hormone (PTH) concentrations. Twelve dogs received a median dose of 0.49 mg/kg (range 0.30–0.69 mg/kg) cinacalcet per os. Venous blood samples were collected at time 0 (before cinacalcet administration), 3, 8, and 24 h following cinacalcet administration. PTH, iCa, and tCa concentrations were measured at each time point and compared to 0 hour concentrations. A significant (50%) decrease in serum PTH occurred at 3 h with a median PTH of 4.6 pmol/L (range 2.7–10.8) at baseline and 1.65 pmol/L (range 0.5–14.7) at 3 h; p =.005. A significant, but not clinically relevant, decrease in serum iCa from a median baseline of 1.340 mmol/L (range 1.32–1.41) to a 3 h median of 1.325 mmol/L (range 1.26–1.39), p =.043, was also observed. tCa concentrations were not different. This study showed that a single dose of cinacalcet leads to transient decreases in iCa and PTH concentrations in healthy dogs. [ABSTRACT FROM AUTHOR]

ABSTRACT: Eggshell is predominantly composed of calcium carbonate, making up about 95% of its composition. Eggshell quality is closely related to the amount of calcium deposition in the shell, which requires chickens to maintain a robust state of calcium metabolism. In this study, we introduced a novel parameter, Total Eggshell Weight (TESW), which measures the total weight of eggshells produced by chickens over a period of 10 consecutive d, providing valuable information on the intensity of calcium metabolism in chickens. Genome-wide association study (GWAS) was conducted to explore the genetic determinants of eggshell calcification in a population of 570 Rhode Island Red laying hens at 90 wk of age. This study revealed a significant association between a specific SNP (rs14249431) and TESW. Additionally, using random forest modeling and 2-tailed testing, we identified 3 genera, Lactobacillus in the jejunum, Lactobacillus, and Fournierella in the cecum, that exhibited a significant association with TESW. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis of claudin-1 and occludin genes in individuals with low TESW and high abundance of jejunal Lactobacillus confirmed that the inhibitory effect of jejunal Lactobacillus on calcium uptake was achieved through the up-regulation of tight junctions in intestinal epithelial cells. Notably, both host and microbial factors influence TESW, displaying a mutually influential relationship between them. The microbiome-wide Genome-Wide Association Study (mb-GWAS) identified significant associations between these 3 genera and specific genomic variants, such as rs316115020 and rs316420452 on chromosome 5, rs313198529 on chromosome 11, linked to Lactobacillus in the cecum. Moreover, rs312552529 on chromosome 1 exhibited potential association with Fournierella in the cecum. This study highlights the influence of host genetics and gut microbiota on calcium deposition in eggshells during the late laying phase, providing a foundational reference for studying calcium metabolism in hens.