Influence of Menstrual Cycle and Oral Contraceptive Phases on Bone (re)modelling Markers in Response to Interval Running.

To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and ß-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases in response to running. 17ß-oestradiol, progesterone, P1NP and ß-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17ß-oestradiol concentrations (pg·ml-1) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85;p = < 0.001) and mid-luteal phase (165.56 ± 80.6;p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24;p < 0.001). Progesterone (ng·ml-1) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586;p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml-1) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64;p = 0.006;) and mid-luteal phase (59.122 ± 11.77;p = 0.002). ß-CTX-1 concentrations (ng·ml-1) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6;p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26;p < 0.001), late-follicular (80.66 ± 16.35;p < 0.001) and mid-luteal phases (64.57 ± 9.68;p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.

Real-world effects, safety, and predictors of the effectiveness of romosozumab in primary and secondary osteoporosis: An observational study.

Romosozumab is an anti-sclerostin antibody that increases bone formation and decreases bone resorption. It became available for patients at high risk of osteoporotic fractures in Japan in 2019. The aim of this study was to clarify the clinical effects, safety, and predictors of the effectiveness of 12 months of romosozumab therapy. The study had an observational pre-post design and included 460 patients. Romosozumab was administered at a dose of 210 mg subcutaneously every 4 weeks for 12 months. The incidence of new fractures, safety, and changes in bone mineral density (BMD) and bone turnover markers were recorded. New fractures occurred in 11 cases (3.0 %). Nine patients (2.0 %) experienced cardiovascular events, which were fatal in 3 (0.65 %). Percent changes in BMD at the spine and total hip at 12 months from baseline were +7.7 % and +1.8 %, respectively. Romosozumab had better effects in patients with good renal function, low spine BMD, and high TRACP-5b at baseline and low TRACP-5b or high P1NP after 1 month of treatment. The percent change in spine BMD at 12 months was significantly lower in patients transitioning from denosumab than in those not previously treated with other anti-osteoporosis agents. Romosozumab is considered to be relatively safe in patients with primary osteoporosis compared to those with secondary osteoporosis. Romosozumab resulted in larger increases in spine BMD in patients with primary osteoporosis who were not previously treated with other anti-osteoporosis therapies and those with low spine BMD at the start of treatment.

Predictive value of bone turnover markers and thyroid indicators for bone metabolism in GD patients after treatment.

Purpose: To investigate the relationship between bone turnover markers (BTMs) and thyroid indicators in Graves' disease (GD) and to further assess predictive value of changes in early stage retrospectively. Methods: We studied 435 patients with GD and 113 healthy physical examiners retrospectively and followed up these two groups of patients after 6 months. We investigated the correlations between BTMs and other 15 observed factors, and analyzed the predictive value of FT3 and FT4 before and after treatment (FT3-P/FT3-A, FT4-P/FT4-A) on whether BTMs recovered. Results: The levels of thyroid hormones and BTMs in GD group were significantly higher than those in control group (P < 0.05) and decreased after 6 months of treatment. FT3, W, Ca and ALP were independent factors in predicting the elevation of OST. Duration of disease, FT3, TSH and ALP were independent factors in predicting the elevation of P1NP. Age, duration of disease, TRAb and ALP were independent factors in predicting the elevation of CTX-1. The AUC of FT3-P/FT3-A and FT4-P/FT4-A for predicting OST recovery were 0.748 and 0.705 (P < 0.05), respectively, and the cut-off values were 0.51 and 0.595. There was no predictive value for P1NP and CTX-1 recovery (P > 0.05). Conclusion: BTMs were abnormally elevated in GD and were significantly correlated with serum levels of FT3, FT4, TRAb, Ca, and ALP. FT3 decreased more than 51% and FT4 dropped more than 59.5% after 6 months of treatment were independent predictors for the recovery of BTMs in GD.

Human Airway Organoids and Multimodal Imaging-Based Toxicity Evaluation of 1-Nitropyrene.

Despite significant advances in understanding the general health impacts of air pollution, the toxic effects of air pollution on cells in the human respiratory tract are still elusive. A robust, biologically relevant in vitro model for recapitulating the physiological response of the human airway is needed to obtain a thorough understanding of the molecular mechanisms of air pollutants. In this study, by using 1-nitropyrene (1-NP) as a proof-of-concept, we demonstrate the effectiveness and reliability of evaluating environmental pollutants in physiologically active human airway organoids. Multimodal imaging tools, including live cell imaging, fluorescence microscopy, and MALDI-mass spectrometry imaging (MSI), were implemented to evaluate the cytotoxicity of 1-NP for airway organoids. In addition, lipidomic alterations upon 1-NP treatment were quantitatively analyzed by nontargeted lipidomics. 1-NP exposure was found to be associated with the overproduction of reactive oxygen species (ROS), and dysregulation of lipid pathways, including the SM-Cer conversion, as well as cardiolipin in our organoids. Compared with that of cell lines, a higher tolerance of 1-NP toxicity was observed in the human airway organoids, which might reflect a more physiologically relevant response in the native airway epithelium. Collectively, we have established a novel system for evaluating and investigating molecular mechanisms of environmental pollutants in the human airways via the combinatory use of human airway organoids, multimodal imaging analysis, and MS-based analyses.

ALKBH5 SUMOylation-mediated FBXW7 m6A modification regulates alveolar cells senescence during 1-nitropyrene-induced pulmonary fibrosis.

Our previous study revealed that 1-nitropyrene (1-NP) exposure evoked pulmonary fibrosis in mice. However, the exact mechanism remained elusive. We found that 1-NP induced telomere damage and cellular senescence in mice lungs, and two alveolar epithelial cells lines. 1-NP downregulated telomere repeat binding factor 2 (TRF2), and upregulated FBXW7. Mechanistically, 1-NP-caused TRF2 ubiquitination and proteasomal degradation depended on E3 ubiquitin ligase activity of FBXW7. Moreover, 1-NP upregulated FBXW7 m6A modification via an ALKBH5-YTHDF1-dependent manner. Further analysis suggested 1-NP promoted ALKBH5 SUMOylation and subsequent proteasomal degradation. Additionally, 1-NP evoked mitochondrial reactive oxygen species (mtROS) overproduction. Mito-TEMPO, a mitochondrial-targeted antioxidant, mitigated 1-NP-caused mtROS overproduction, ALKBH5 SUMOylation, FBXW7 m6A modification, TRF2 degradation, cellular senescence, and pulmonary fibrosis. Taken together, mtROS-initiated ALKBH5 SUMOylation and subsequent FBXW7 m6A modification is indispensable for TRF2 degradation and cellular senescence in alveolar epithelial cells during 1-NP-induced pulmonary fibrosis. Our study provides target intervention measures towards 1-NP-evoked pulmonary fibrosis.

Bone Turnover Markers, n-Terminal Propeptide of Type I Procollagen and Tartrate-Resistant Acid Phosphatase Type 5b, for Predicting Castration Resistance in Prostate Cancer.

Bone is a common site of prostate cancer metastasis. Bone turnover markers n-terminal propeptide of type I procollagen (P1NP) and tartrate-resistant acid phosphatase type 5b (TRACP-5b) are highly sensitive to bone remodeling activity. However, their prognostic significance as markers of prostate cancer is unknown. This study retrospectively examined the usefulness of P1NP and TRACP-5b as prognostic biomarkers. Castration-resistant prostate cancer recurrence-free survival (CFS) was estimated using the Kaplan-Meier method. A predictive model for CFS was constructed using multivariate analysis. This study enrolled 255 patients diagnosed with prostate cancer at Kanazawa University Hospital. The median follow-up was 115.1 months. Patients with both high serum P1NP and TRACP-5b levels, defined as having a poor bone turnover category (BTC), had significantly shorter CFS. Multivariate analysis identified Gleason score, metastasis, and BTC poor as predictors for castration resistance in prostate cancer. Using these three factors, a prognostic model was established, categorizing patients into low-risk (no or one factor) and high-risk (two or three factors) groups. In the low-risk group, the median CFS was not reached, contrasting with 19.1 months in the high-risk group (hazard ratio, 32.23, p < 0.001). Combining P1NP and TRACP-5b may better predict castration resistance.

Effects of Exogenous GIP and GLP-2 on Bone Turnover in Individuals With Type 2 Diabetes.

CONTEXT: Individuals with type 2 diabetes (T2D) have an increased risk of bone fractures despite normal or increased bone mineral density. The underlying causes are not well understood but may include disturbances in the gut-bone axis, in which both glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) are regulators of bone turnover. Thus, in healthy fasting participants, both exogenous GIP and GLP-2 acutely reduce bone resorption. OBJECTIVE: The objective of this study was to investigate the acute effects of subcutaneously administered GIP and GLP-2 on bone turnover in individuals with T2D. METHODS: We included 10 men with T2D. Participants met fasting in the morning on 3 separate test days and were injected subcutaneously with GIP, GLP-2, or placebo in a randomized crossover design. Blood samples were drawn at baseline and regularly after injections. Bone turnover was estimated by circulating levels of collagen type 1 C-terminal telopeptide (CTX), procollagen type 1 N-terminal propeptide (P1NP), sclerostin, and PTH. RESULTS: GIP and GLP-2 significantly reduced CTX to (mean ± SEM) 66 ± 7.8% and 74 ± 5.9% of baseline, respectively, compared with after placebo (P = .001). In addition, P1NP and sclerostin increased acutely after GIP whereas a decrease in P1NP was seen after GLP-2. PTH levels decreased to 67 ± 2.5% of baseline after GLP-2 and to only 86 ± 3.4% after GIP. CONCLUSION: Subcutaneous GIP and GLP-2 affect CTX and P1NP in individuals with T2D to the same extent as previously demonstrated in healthy individuals.

Increased bone resorption that outpaces increased bone formation: An important pathology of rapidly destructive coxarthrosis.

Rapid joint destruction caused by rapidly destructive coxarthrosis (RDC) can increase surgical complexity and intraoperative blood loss. This single-center retrospective study investigates osteoporosis-related biomarkers for early RDC diagnosis and explores new treatment targets. We included 398 hip joints from patients who underwent total hip arthroplasty, examining medical records for preoperative patient demographics, bone mineral density of the hip and lumbar spine from dual-energy X-ray absorptiometry scans, and osteoporosis-related biomarkers including TRACP-5b, total P1NP, intact parathyroid hormone, and homocysteine. We compared RDC and osteoarthritis (OA) patients, and univariate analysis showed that RDC patients were older (p < 0.001) and had lower serum levels of albumin (p < 0.001) and higher serum levels of TRACP-5b, total P1NP (p < 0.001), and homocysteine (p = 0.006). Multivariable analysis showed that the ratio of serum TRACP-5b to total P1NP had a more significant difference in RDC patients than in OA patients (p = 0.04). Serum TRACP-5b levels were negatively correlated with the time between RDC onset and blood collection, and Japanese Orthopedic Association pain score. Receiver operating characteristic curve analysis revealed that the ratio of serum TRACP-5b to total P1NP had the highest area under the curve value. This study is the first to demonstrate that the ratio of serum TRACP-5b to total P1NP-increased bone resorption that outpaces increased bone formation-is significantly elevated in patients with RDC and that TRACP-5b is higher in the early stages of RDC. Inhibiting serum levels of TRACP-5b, activated osteoclasts, during early RDC may suppress disease progression.

Effect of Anamorelin, a Ghrelin Receptor Agonist, on Muscle and Bone in Adults With Osteosarcopenia.

CONTEXT: Anamorelin, a ghrelin receptor agonist known to stimulate the pulsatile release of GH from the pituitary, has the potential to improve musculoskeletal health in adults with osteosarcopenia. OBJECTIVE: To determine the effect of anamorelin treatment for 1 year on muscle mass and strength and on biochemical markers of bone turnover in adults with osteosarcopenia (OS). DESIGN: Randomized, placebo-controlled, 1-year anamorelin intervention trial. SETTING: The Bone Metabolism Laboratory at the USDA Nutrition Center at Tufts University. PARTICIPANTS: 26 men and women, age 50 years and older, with OS. MAIN OUTCOME MEASURES: Muscle mass by D3-creatine dilution and lean body mass (LBM) and bone mineral density (BMD) by dual-energy X-ray absorptiometry, muscle strength, serum IGF-1, and bone turnover markers, serum procollagen 1 intact N-terminal (P1NP), and C-terminal telopeptide (CTX). RESULTS: Anamorelin did not have a significant effect on muscle mass or LBM; it significantly increased knee flexion torque at 240°/s by 20% (P = .013) and had a similar nonstatistically significant effect on change in knee extension; it increased bone formation (P1NP) by 75% (P = .006) and had no significant effect on bone resorption (CTX) or BMD. Serum IGF-1 increased by 50% in the anamorelin group and did not change in the placebo group (P = .0001 for group difference). CONCLUSION: In this pilot study, anamorelin did not significantly alter muscle mass; however, it may potentially improve lower extremity strength and bone formation in addition to increasing circulating IGF-1 levels in adults with OS. Further study of anamorelin in this population is warranted.

Parathyroidectomy Improves Bone Density in Women With Primary Hyperparathyroidism and Preoperative Osteopenia.

CONTEXT: Osteoporosis and/or bone fractures are indications of parathyroidectomy in primary hyperparathyroidism (PHPT), especially in women. However, the benefit of surgery in patients with osteopenia remains unclear. OBJECTIVE: To evaluate bone mineral density (BMD) and bone remodeling biomarkers changes 1 year after parathyroidectomy in women with PHPT. DESIGN: In the prospective, monocentric, observational prospective cohort with primary hyperparathyroidism patients (CoHPT) cohort, women operated for sporadic PHPT since 2016 with ≥1 year follow-up were included. BMD (dual-X ray absorptiometry) and bone remodeling biomarkers [cross-linked C-telopeptide (CTX), procollagen type 1 N-terminal propeptide (P1NP), and bone-specific alkaline phosphatases] were assessed before and 1 year after parathyroidectomy. SETTING: Referral center. PATIENTS: A total of 177 women with PHPT (62.5 ± 13.3 years, 83.1% menopausal, 43.9% osteopenic, and 45.1% osteoporotic) were included. INTERVENTION: Parathyroidectomy. MAIN OUTCOME MEASURE: BMD change between before and 1 year after parathyroidectomy. RESULTS: Parathyroidectomy resulted in significant increase in BMD and decrease in serum bone remodeling biomarker concentrations. In the 72 patients with baseline osteopenia, mean BMD significantly increased at the lumbar spine [+0.05 g/cm2 (95% confidence interval [CI], 0.03-0.07)], the femoral neck [+0.02 g/cm2 (95% CI 0.00-0.04)], the total hip [+0.02 g/cm2 (95% CI 0.01-0.02)], and the forearm [+0.01 (95% CI 0.00-0.02)], comparable to osteoporotic patients. Among osteopenic patients, those with individual BMD gain (>0.03 g/cm2) at ≥1 site had higher preoperative serum CTX, P1NP, and urine calcium concentrations than those without improvement. CONCLUSION: Parathyroidectomy significantly improved BMD and remodeling biomarkers in women with osteopenia, thereby supporting the benefit of parathyroidectomy in these patients. Preoperative serum CTX and P1NP concentrations could be useful to predict expected BMD gain.

Night shift work and serum markers of bone turnover in male shift workers.

Night shift work is related to sleep disorders, disruption of circadian rhythm and low serum levels of vitamin D. It is known that all these conditions can adversely affect bone mass. The rate of bone turnover can be assessed through the measurement of molecules called bone turnover markers, including C-terminal telopeptide fragment of type I collagen (CTX) and procollagen type I N-terminal propeptide (P1NP). In this study, we evaluated the serum levels of CTX, P1NP and 25-Hydroxy Vitamin D in 82 male subjects (42 daytime workers and 40 night shift workers) to assess the possible risk of osteoporosis in male shift workers. Serum levels of CTX and P1NP were found to be higher in night shift workers than in daytime workers. No significant difference was found in vitamin D levels between night shift and daytime workers. The increased CTX and P1NP levels reveal a higher rate of bone turnover in night shift workers and thus a possible increased risk of osteoporosis in this category of workers compared with daytime workers. In view of this, our results highlight the importance of further studies investigating the bone health in male night shift workers.

Impact of Intravenous Iron Substitution on Serum Phosphate Levels and Bone Turnover Markers-An Open-Label Pilot Study.

The association between intravenous iron substitution therapy and hypophosphatemia was previously reported in patients with iron deficiency anemia. However, the extent of hypophosphatemia is thought to depend on the type of iron supplementation. We hypothesized that the intravenous application of ferric carboxymaltose and iron sucrose leads to a different longitudinal adaptation in serum phosphate levels. In this open-label pilot study, a total of 20 patients with inflammatory bowel diseases or iron deficiency anemia were randomly assigned to one of two study groups (group 1: ferric carboxymaltose, n = 10; group 2: iron sucrose, n = 10). Serum values were controlled before iron substitution therapy, as well as 2, 4, and 12 weeks after the last drug administration. The primary objective of the study was the longitudinal evaluation of serum phosphate levels after iron substitution therapy with ferric carboxymaltose and iron sucrose. The secondary objective was the longitudinal investigation of calcium, 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone, procollagen type 1 amino-terminal propeptide (P1NP), beta-CrossLaps (CTX), hemoglobin (Hb), iron, ferritin, and transferrin saturation levels. Two weeks after drug administration, phosphate levels were significantly lower (p < 0.001) in group 1 and ferritin levels were significantly higher (p < 0.001) in group 1. Phosphate levels (0.8-1.45 mmol/L) were below the therapeutic threshold and ferritin levels (10-200 ng/mL for women and 30-300 ng/mL for men) were above the therapeutic threshold in group 1. P1NP (15-59 µg/L) and CTX (<0.57 ng/mL) levels were above the therapeutic threshold in group 2. Four weeks after drug administration, significant differences were still observed between both study groups for phosphate (p = 0.043) and ferritin (p = 0.0009). All serum values except for Hb were within the therapeutic thresholds. Twelve weeks after drug administration, no differences were observed in all serum values between both study groups. Hb values were within the therapeutic threshold in both study groups. Serum 25(OH)D levels did not differ between both study groups throughout the whole study period and remained within the therapeutic threshold.

Seasonality of Polyaromatic Hydrocarbons (PAHs) and Their Derivatives in PM2.5 from Ljubljana, Combustion Aerosol Source Apportionment, and Cytotoxicity of Selected Nitrated Polyaromatic Hydrocarbons (NPAHs).

Airborne particulate matter (PM) is a vector of many toxic pollutants, including polyaromatic hydrocarbons (PAHs) and their derivatives. Especially harmful is the fine fraction (PM2.5), which penetrates deep into the lungs during inhalation and causes various diseases. Amongst PM2.5 components with toxic potential are nitrated PAHs (NPAHs), knowledge of which is still rudimentary. Three of the measured NPAHs (1-nitropyrene (1-nP), 9-nitroanthracene (9-nA), and 6-nitrochrysene (6-nC)) were detected in ambient PM2.5 from Ljubljana, Slovenia, along with thirteen non-nitrated PAHs. The highest concentrations of pollutants, which are closely linked with incomplete combustion, were observed in the cold part of the year, whereas the concentrations of NPAHs were roughly an order of magnitude lower than those of PAHs throughout the year. Further on, we have evaluated the toxicity of four NPAHs, including 6-nitrobenzo[a]pyrene (6-nBaP), to the human kidney cell line, HEK293T. The most potent was 1-nP (IC50 = 28.7 µM), followed by the other three NPAHs, whose IC50 was above 400 or 800 µM. According to our cytotoxicity assessment, atmospheric 1-nP is the most harmful NPAH among the investigated ones. Despite low airborne concentrations of NPAHs in ambient air, they are generally considered harmful to human health. Therefore, systematic toxicological assessment of NPAHs at different trophic levels, starting with cytotoxicity testing, is necessary in order to accurately evaluate their threat and adopt appropriate abatement strategies.

The short-term effects of CGRP monoclonal antibodies on bone turnover: A prospective cohort study.

BACKGROUND: Calcitonin gene-related peptide monoclonal antibodies (CGRP mAb) are an effective treatment of migraine however may have possible off-target effects. Pre-clinical studies implicate CGRP in several aspects of bone turnover and homeostasis. The clinical effect of CGRP mAb on bone turnover is not known, however. METHODS: Between June 2021 and July 2022, a multi-centre prospective cohort study was undertaken with eligible patients undergoing paired testing of the validated bone turnover markers procollagen type I N-terminal propeptide (P1NP) and serum C-terminal telopeptide of type I collagen (CTX) prior to and at least three months following administration of a CGRP mAb. RESULTS: A total of 45 patients with a mean age of 41.8 (SD 11.9) were included in the final analysis, all of whom received a ligand-targeting CGRP mAb. Administration of a CGRP mAb was associated with a statistically significant increase in P1NP from 44.5 microg/L to 51.5 microg/L (p = 0.004), but no significant change in CTX. CONCLUSION: In otherwise homeostatic conditions, short-term administration of a CGRP mAb is associated with increased P1NP, a bone formation marker but not with increased CTX, a bone resorption marker. Further study is required to validate these findings over longer time periods, in a larger cohort, and in pre-existing states of increased calcium stress and bone-turnover.

Reference intervals for plasma ß-CTX and P1NP in children: A systematic review and pooled estimates.

OBJECTIVE: Reference intervals for plasma P1NP and ß-CTX in children and adolescents from several studies have recently been published. The aim of this study was to combine the available data into a set of reference intervals for use in clinical laboratories. DESIGN AND METHODS: A systematic literature search for primary studies reporting reference intervals for plasma P1NP and ß-CTX in infants, children and adolescents using the Roche methods was carried out. Reference limits were extracted. For each year of age, mean upper and lower reference limits were calculated, weighted by the number of subjects in each study, and were plotted against age. Proposed reference limits were developed from the weighted mean data with age partitions determined pragmatically. RESULTS: Reference limits for clinical use for females to 25 years and males to 18 years, based on the weighted mean reference data, are presented. Ten studies contributed to the pooled analysis. The proposed reference limits are identical for males and females <9 years age, prior to the pubertal growth spurt. For ß-CTX, the weighted mean reference limits showed relatively constant values during the pre-pubertal years but a marked increase during puberty before a rapid decline towards adult values. Those for P1NP showed high values declining rapidly in the first 2 years of life, followed by a modest increase during early puberty. Limited published information for late adolescent and young adult subjects was noted. CONCLUSIONS: The proposed reference intervals may be useful for clinical laboratories reporting these bone turnover markers measured by the Roche assays.

1-Nitropyrene disrupts testicular steroidogenesis via oxidative stress-evoked PERK-eIF2α pathway.

Our previous study showed 1-Nitropyrene (1-NP) exposure disrupted testicular testosterone synthesis in mouse, but the exact mechanism needs further investigation. The present research found 4-phenylbutyric acid (4-PBA), an endoplasmic reticulum (ER) stress inhibitor, recovered 1-NP-induced ER stress and testosterone synthases reduction in TM3 cells. GSK2606414, a protein kinase-like ER kinase (PERK) kinase inhibitor, attenuated 1-NP-induced PERK-eukaryotic translation initiation factor 2α (eIF2α) signaling activation and downregulation of steroidogenic proteins in TM3 cells. Both 4-PBA and GSK2606414 attenuated 1-NP-induced steroidogenesis disruption in TM3 cells. Further studies used N-Acetyl-L-cysteine (NAC) as a classical antioxidant to explore whether oxidative stress-activated ER stress mediated 1-NP-induced testosterone synthases reduction and steroidogenesis disruption in TM3 cells and mouse testes. The results showed NAC pretreatment mitigated oxidative stress, and subsequently attenuated ER stress, particularly PERK-eIF2α signaling activation, and downregulation of testosterone synthases in 1-NP-treated TM3 cells. More importantly, NAC extenuated 1-NP-induced testosterone synthesis in vitro and in vivo. The current work indicated that oxidative stress-caused ER stress, particularly PERK-eIF2α pathway activation, mediates 1-NP-downregulated steroidogenic proteins and steroidogenesis disruption in TM3 cells and mouse testes. Significantly, the current study provides a theoretical basis and demonstrates the experimental evidence for the potential application of antioxidant, such as NAC, in public health prevention, particularly in 1-NP-induced endocrine disorder.

The efficacy of alendronate for the treatment of thalassemia-associated osteoporosis: a randomized controlled trial.

Background: With adequate blood transfusion and iron chelation, thalassemia patients have a longer life expectancy and experience long-term metabolic complications, including osteoporosis, fractures, and bone pain. Alendronate, an oral bisphosphonate, is currently used to treat various types of osteoporosis. However, the efficacy for the treatment of thalassemia-associated osteoporosis remains unclear. Methods: We conducted a randomized controlled trial to evaluate the efficacy of alendronate for the treatment of osteoporosis in thalassemia patients. Patients were included if they were males (18-50 years) or premenopausal females with low bone mineral density (BMD) (Z-score < -2.0 SD) or positive vertebral deformities from vertebral fracture analysis (VFA). Stratified randomization was performed according to sex and transfusion status. Patients were 1:1 allocated to receive once weekly alendronate 70 mg orally or placebo for a total duration of 12 months. BMD and VFA were re-evaluated at 12 months. Markers of bone resorption (C-terminal crosslinking telopeptide of type I collagen; CTX) and bone formation (Procollagen type I N-terminal propeptide; P1NP), and pain scores were measured at baseline, 6 months, and 12 months. The primary outcome was the change of BMD. The secondary endpoints were changes in bone turnover markers (BTM) and pain scores. Results: A total of 51 patients received the study drug, 28 patients were assigned to receive alendronate and 23 patients to receive placebo. At 12 months, patients in the alendronate group had significant improvement of BMD at L1-L4 compared to their baseline (0.72 ± 0.11 vs 0.69 ± 0.11 g/cm2, p = 0.004), while there was no change in the placebo group (0.69 ± 0.09 vs 0.70 ± 0.06 g/cm2, p = 0.814). There was no significant change of BMD at femoral neck in both groups. Serum BTMs were significantly decreased among patients receiving alendronate at 6 and 12 months. The mean back pain score was significantly reduced compared to the baseline in both groups (p = 0.003). Side effects were rarely found and led to a discontinuation of the study drug in 1 patient (grade 3 fatigue). Conclusion: Alendronate 70 mg orally once weekly for 12 months effectively improves BMD at L-spine, reduces serum BTMs, and alleviates back pain in thalassemia patients with osteoporosis. The treatment was well tolerated and had a good safety profile.

An Increase in Plasma Sodium Levels Is Associated With an Increase in Osteoblast Function in Chronic SIAD.

CONTEXT: Hyponatremia is associated with increased risk for osteoporosis. Preclinical studies in untreated hyponatremia suggest osteoclast upregulation, whereas a clinical study showed improved osteoblast function after hyponatremia normalization in hospitalized patients with syndrome of inappropriate antidiuresis (SIAD). OBJECTIVE: This work aimed to investigate the effect of an increase in sodium on bone turnover, that is, the ratio of the osteoblast marker procollagen type 1 N-terminal propeptide (P1NP) to the osteoclast marker cross-linked C-terminal telopeptide of type 1 collagen (CTX), in outpatients with chronic SIAD. METHODS: A predefined secondary analysis was conducted of the 2-month double-blind, crossover, placebo-controlled SANDx Trial (NCT03202667) performed from December 2017 to August 2021. Participants included 11 outpatients with chronic SIAD: 6 women, median age 73 years, who received a 4-week treatment with 25-mg empagliflozin or placebo. Main outcome measures included the relationship between the change in bone formation index (BFI), defined as P1NP/CTX, and the change in plasma sodium levels. RESULTS: Changes in sodium were positively correlated with changes in BFI and P1NP (BFI: ρ=.55; P < .001; P1NP: ρ=.45; P = .004) but not with CTX (P = .184) and osteocalcin (P = .149). A sodium increase of 1 mmol/l was associated with an increase of 5.21 in BFI (95% CI, 1.41-9.00; P = .013) and with an increase of 1.48 µg/l in P1NP (95% CI, .26-2.62; P = .03). The effect of sodium change on bone markers was independent of the study medication empagliflozin. CONCLUSION: An increase in plasma sodium levels in outpatients with chronic hyponatremia due to SIAD, even when mild, was associated with an increase in bone formation index (P1NP/CTX) triggered by an increase in P1NP, a surrogate marker of osteoblast function.

Acarbose diminishes postprandial suppression of bone resorption in patients with type 2 diabetes.

AIMS: The alpha-glucosidase inhibitor acarbose is an antidiabetic drug delaying assimilation of carbohydrates and, thus, increasing the amount of carbohydrates in the distal parts of the intestines, which in turn increases circulating levels of the gut-derived incretin hormone glucagon-like peptide 1 (GLP-1). As GLP-1 may suppress bone resorption, acarbose has been proposed to potentiate meal-induced suppression of bone resorption. We investigated the effect of acarbose treatment on postprandial bone resorption in patients with type 2 diabetes and used the GLP-1 receptor antagonist exendin(9-39)NH2 to disclose contributory effect of acarbose-induced GLP-1 secretion. METHODS: In a randomised, placebo-controlled, double-blind, crossover study, 15 participants with metformin-treated type 2 diabetes (2 women/13 men, age 71 (57-85 years), BMI 29.7 (23.6-34.6 kg/m2), HbA1c 48 (40-74 mmol/mol)/6.5 (5.8-11.6 %) (median and range)) were subjected to two 14-day treatment periods with acarbose and placebo, respectively, separated by a six-week wash-out period. At the end of each period, circulating bone formation and resorption markers were assessed during two randomised 4-h liquid mixed meal tests (MMT) with infusions of exendin(9-39)NH2 and saline, respectively. Glucagon-like peptide 2 (GLP-2) was also assessed. RESULTS: Compared to placebo, acarbose impaired the MMT-induced suppression of CTX as assessed by baseline-subtracted area under curve (P = 0.0037) and nadir of CTX (P = 0.0128). During acarbose treatment, exendin(9-39)NH2 infusion lowered nadir of CTX compared to saline (P = 0.0344). Neither parathyroid hormone or the bone formation marker procollagen 1 intact N-terminal propeptide were affected by acarbose or GLP-1 receptor antagonism. Acarbose treatment induced a greater postprandial GLP-2 response than placebo treatment (P = 0.0479) and exendin(9-39)NH2 infusion exacerbated this (P = 0.0002). CONCLUSIONS: In patients with type 2 diabetes, treatment with acarbose reduced postprandial suppression of bone resorption. Acarbose-induced GLP-1 secretion may contribute to this phenomenon as the impairment was partially reversed by GLP-1 receptor antagonism. Also, acarbose-induced reductions in other factors reducing bone resorption, e.g. glucose-dependent insulinotropic polypeptide, may contribute.

Bone turnover following high-impact exercise is not modulated by collagen supplementation in young men: A randomized cross-over trial.

INTRODUCTION: We assessed whether collagen supplementation augments the effects of high-impact exercise on bone turnover and whether a higher exercise frequency results in a greater benefit for bone metabolism. METHODS: In this randomized, cross-over trial, 14 healthy males (age 24 ± 4 y, BMI 22.0 ± 2.1 kg/m2) performed 5-min of high-impact exercise once (JUMP+PLA and JUMP+COL) or twice daily (JUMP2+COL2) during a 3-day intervention period, separated by a 10-day wash out period. One hour before every exercise bout participants ingested 20 g hydrolysed collagen (JUMP+COL and JUMP2+COL2) or a placebo control (JUMP+PLA). Blood markers of bone formation (P1NP) and resorption (CTXI) were assessed in the fasted state before the ingestion of the initial test drinks and 24, 48, and 72 h thereafter. In JUMP+PLA and JUMP+COL, additional blood samples were collected in the postprandial state at 1, 2, 3, 4, 5 and 13 h after ingestion of the test drink. RESULTS: In the postprandial state, serum P1NP concentrations decreased marginally from 99 ± 37 to 93 ± 33 ng/mL in JUMP+COL, and from 97 ± 32 to 92 ± 31 ng/mL in JUMP+PLA, with P1NP levels having returned to baseline levels after 13 h (time-effect, P = 0.053). No differences in serum P1NP concentrations were observed between JUMP+PLA and JUMP+COL (time x treatment, P = 0.58). Serum CTX-I concentrations showed a ~ 50 % decline (time, P < 0.001) in the postprandial state in JUMP+COL (0.9 ± 0.3 to 0.4 ± 0.2 ng/mL) and JUMP+PLA (0.9 ± 0.3 to 0.4 ± 0.2 ng/mL), with no differences between treatments (time x treatment, P = 0.17). Fasted serum P1NP concentrations increased ~8 % by daily jumping exercise (time-effect, P < 0.01), with no differences between treatments (time x treatment, P = 0.71). Fasted serum CTX-I concentrations did not change over time (time-effect, P = 0.41) and did not differ between treatments (time x treatment, P = 0.58). CONCLUSIONS: Five minutes of high-impact exercise performed daily stimulates bone formation during a 3-day intervention period. This was indicated by an increase in fasted serum P1NP concentrations, rather than an acute increase in post-exercise serum P1NP concentrations. Collagen supplementation or an increase in exercise frequency does not further increase serum P1NP concentrations. The bone resorption marker CTX-I was not affected by daily short-duration high-impact exercise with or without concurrent collagen supplementation.