Soy Isoflavones and Bone Health: Focus on the RANKL/RANK/OPG Pathway.

Bone remodels via resorption and formation, two phenomena that continuously occur in bone turnover. The RANKL/RANK/OPG pathway is one of the several mechanisms that affect bone turnover. The RANKL/OPG ratio has a substantial role in bone resorption. An imbalance between formation and resorption is related to an increased RANKL/OPG balance. OPG, a member of this system, can bind to RANKL and suppress RANK-RANKL interaction, and subsequently, inhibit further osteoclastogenesis. The serum levels of RANKL and OPG in the bone microenvironment are vital for osteoclasts formation. The RANK/RANKL/OPG system plays a role in the pathogenesis of bone disorders. This system can be considered a new treatment target for bone disorders. Soy isoflavones affect the RANK/RANKL/OPG system through numerous mechanisms. Soy isoflavones decrease RANKL levels and increase OPG levels. Therefore, isoflavones improve bone metabolism and decrease bone resorption. Soy isoflavones decrease serum markers of bone resorption and improve bone metabolism. However, while the available data are promising, the results of several studies reported no change in RANKL and OPG levels with isoflavones supplementation. In this regard, current evidence is insufficient for conclusive approval of the efficacy of isoflavones on RANKL/RANK/OPG and further research, including animal and human studies, are needed to confirm the effect of soy isoflavones on the RANKL/RANK/OPG pathway. This study was a review of available evidence to determine the role of isoflavones in bone hemostasis and the RANK/RANKL/OPG pathway. The identification of the effects of isoflavones on the RANKL/RANK/OPG pathway directs future studies and leads to the development of effective treatment strategies for bone disorders.

Associations of vascular and bone status in arthritis patients.

Cardiovascular (CV) disease and osteoporosis (OP) have been associated with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Bone and vascular biomarkers and parameters along with the effect of 1-year anti-TNF therapy on these markers were assessed in order to determine correlations between vascular pathophysiology and bone metabolism in RA and AS. Thirty-six patients treated with etanercept or certolizumab pegol and 17 AS patients treated with ETN were included in a 12-month follow-up study. Bone and vascular markers were previously assessed by ELISA. Bone density was measured by DXA and quantitative CT (QCT). Flow-mediated vasodilation (FMD), common carotid intima-media thickness (IMT) and pulse-wave velocity (PWV) were assessed by ultrasound. Multiple correlation analyses indicated associations between bone and vascular markers. Osteoprotegerin, sclerostin and cathepsin K were significantly associated with FMD, IMT and PWV, respectively (p < 0.05). Moreover, total and trabecular BMD determined by QCT inversely correlated with IMT (p < 0.05). On the other hand, among vascular parameters, platelet-derived growth factor BB and IMT correlated with DXA femoral and QCT total BMD, respectively (p < 0.05). In the RM-ANOVA analysis, anti-TNF treatment together with baseline osteocalcin, procollagen 1 N-terminal propeptide (P1NP) or vitamin D3 levels determined one-year changes in IMT (p < 0.05). In the MANOVA analysis, baseline disease activity indices (DAS28, BASDAI), the one-year changes in these indices, as well as CRP exerted effects on multiple correlations between bone and vascular markers (p < 0.05). As the pattern of interactions between bone and vascular biomarkers differed between baseline and after 12 months, anti-TNF therapy influenced these associations. We found a great number of correlations in our RA and AS patients undergoing anti-TNF therapy. Some of the bone markers have been associated with vascular pathophysiology, while some vascular markers correlated with bone status. In arthritis, systemic inflammation and disease activity may drive both vascular and bone disease.

14-3-3ζ: A suppressor of inflammatory arthritis.

Inflammatory arthritis (IA) is a common disease that affects millions of individuals worldwide. Proinflammatory events during IA pathogenesis are well studied; however, loss of protective immunity remains underexplored. Earlier, we reported that 14-3-3zeta (ζ) has a role in T-cell polarization and interleukin (IL)-17A signal transduction. Here, we demonstrate that 14-3-3ζ knockout (KO) rats develop early-onset severe arthritis in two independent models of IA, pristane-induced arthritis and collagen-induced arthritis. Arthritic 14-3-3ζ KO animals showed an increase in bone loss and immune cell infiltration in synovial joints. Induction of arthritis coincided with the loss of anti-14-3-3ζ antibodies; however, rescue experiments to supplement the 14-3-3ζ antibody by passive immunization did not suppress arthritis. Instead, 14-3-3ζ immunization during the presymptomatic phase resulted in significant suppression of arthritis in both wild-type and 14-3-3ζ KO animals. Mechanistically, 14-3-3ζ KO rats exhibited elevated inflammatory gene signatures at the messenger RNA and protein levels, particularly for IL-1ß. Furthermore, the immunization with recombinant 14-3-3ζ protein suppressed IL-1ß levels, significantly increased anti-14-3-3ζ antibody levels and collagen production, and preserved bone quality. The 14-3-3ζ protein increased collagen expression in primary rat mesenchymal cells. Together, our findings indicate that 14-3-3ζ causes immune suppression and extracellular remodeling, which lead to a previously unrecognized IA-suppressive function.

Network Pharmacological Study of Achyranthis bidentatae Radix Effect on Bone Trauma.

PURPOSE: Bone trauma is a clinical condition that afflicts the majority of the world's population. For the management of bone trauma, the underlying mechanisms of the drugs effective for bone healing are deemed necessary. Achyranthis bidentatae Radix (ABR) is a popular alternative medicine recommended in the treatment of bone trauma and injury, yet its mechanism of action persists to be vague. This study was conducted for the evaluation of the mode of action of ABR through network pharmacology in treating bone trauma. METHODS: An extensive survey of published works led to the development of a drug-target database, after which multiple protein targets for bone trauma were discerned. The protein-protein interaction network was developed by utilizing the STITCH database and gene ontology (GO) enrichment analysis using Cytoscape and ClueGO. Moreover, docking studies were performed for revealing the affinity of various ingredients with IL6. RESULTS: The extensive literature survey yielded the presence of 176 components in ABR, and 151 potential targets were acquired. Scrutinization of these targets revealed that 21 potential targets were found to be associated with bone trauma. Out of which, some remarkable targets such as IL6, MAPK14, MAPK8, SRC, PTGS2, and MMP2 were observed to be associated in the functional interaction of ABR. According to docking results, several ingredients of ABR such as Baicalien, Copistine, Epiberberine, Kaempferol, and Palmatine have the lowest docking scores (range between -6 and -7). CONCLUSIONS: The results of the study elucidated that ABR can positively be utilized for the management of bone trauma, which can be mediated by multiple molecular mechanisms such as ERBB2 signaling pathway, positive regulation of oxidoreductase activity, JNK cascade pathway, multicellular organism metabolic process, T cell costimulation, and the positive regulation of MAPK activity. The findings also suggest that several ingredients of ABR such as Baicalien, Copistine, Epiberberine, Kaempferol, and Palmatine have good affinity with IL6, suggesting the promising potential of ABR in treating bone trauma, likely through IL6.

Anacardic acid-mediated regulation of osteoblast differentiation involves mitigation of inflammasome activation pathways.

Disruption of the finely tuned osteoblast-osteoclast balance is the underlying basis of several inflammatory bone diseases, such as osteomyelitis, osteoporosis, and septic arthritis. Prolonged and unrestrained exposure to inflammatory environment results in reduction of bone mineral density by downregulating osteoblast differentiation. Earlier studies from our laboratory have identified that Anacardic acid (AA), a constituent of Cashew nut shell liquid that is used widely in traditional medicine, has potential inhibitory effect on gelatinases (MMP2 and MMP9) which are over-expressed in numerous inflammatory conditions (Omanakuttan et al. in Mol Pharmacol, 2012 and Nambiar et al. in Exp Cell Res, 2016). The study demonstrated for the first time that AA promotes osteoblast differentiation in lipopolysaccharide-treated osteosarcoma cells (MG63) by upregulating specific markers, like osteocalcin, receptor activator of NF-κB ligand, and alkaline phosphatase. Furthermore, expression of the negative regulators, such as nuclear factor-κB, matrix metalloproteinases (MMPs), namely MMP13, and MMP1, along with several inflammatory markers, such as Interleukin-1ß and Nod-like receptor protein 3 were downregulated by AA. Taken together, AA expounds as a novel template for development of potential pharmacological therapeutics for inflammatory bone diseases.

A potential role for astaxanthin in the treatment of bone diseases (Review).

Alterations in molecular signaling impair cellular functions and induce degenerative diseases. Among the factors affecting intracellular signaling pathways, oxidative stress serves an important role. Astaxanthin (3,3'­dihydroxy­ß, ß­carotene-4,4'­dione), a pigment found in aquatic organisms, belongs to the xanthophylls family. Astaxanthin exerts a strong antioxidant activity and is widely used in food, cosmetic and pharmaceutical industries. Oxidative stress damages bone homeostasis by producing reactive oxygen species and increasing the production of pro­resorption cytokines, such as interleukin (IL)­1, tumor necrosis factor­α and IL­6. Therefore, antioxidant molecules can counteract the negative effects of oxidative stress on bone. Accordingly, previous studies have demonstrated that supplementation of astaxanthin in bone contributes to the restoration of bone homeostasis. The present review summarizes the negative effects of oxidative stress in bone and explores the role of astaxanthin in counteracting skeletal injuries consequent to oxidative stress.

Updating the role of matrix metalloproteinases in mineralized tissue and related diseases.

Bone development and healing processes involve a complex cascade of biological events requiring well-orchestrated synergism with bone cells, growth factors, and other trophic signaling molecules and cellular structures. Beyond health processes, MMPs play several key roles in the installation of heart and blood vessel related diseases and cancer, ranging from accelerating metastatic cells to ectopic vascular mineralization by smooth muscle cells in complementary manner. The tissue inhibitors of MMPs (TIMPs) have an important role in controlling proteolysis. Paired with the post-transcriptional efficiency of specific miRNAs, they modulate MMP performance. If druggable, these molecules are suggested to be a platform for development of "smart" medications and further clinical trials. Thus, considering the pleiotropic effect of MMPs on mammals, the purpose of this review is to update the role of those multifaceted proteases in mineralized tissues in health, such as bone, and pathophysiological disorders, such as ectopic vascular calcification and cancer.

Bone metabolism markers and hungry bone syndrome after parathyroidectomy in dialysis patients with secondary hyperparathyroidism.

OBJECTIVE: To explore the short-term variation in bone metabolic markers and the characteristics of hungry bone syndrome (HBS) after parathyroidectomy (PTX) with forearm autotransplantation in uremic patients with secondary hyperparathyroidism (SHPT) and to provide a basis for the pathogenesis, diagnosis and treatment of metabolic bone disease in SHPT. METHODS: A total of 115 patients with SHPT receiving PTX from July 2015 to December 2017, hospitalized at the First Affiliated Hospital of Nanjing Medical University, were enrolled in our study. We retrospectively analyzed the baseline clinical data, the levels of bone metabolism markers before and on the third day after PTX, and the risk factors predicting HBS. RESULTS: Preoperative baseline data showed that the levels of bone metabolic markers such as bone metabolism-regulating hormones: iPTH, calcitonin (CT); bone formation markers: phosphatase (ALP), osteocalcin (OC); bone resorption markers: type I collagen cross-linked N-telopeptides (NTX), type I collagen cross-linked C-telopeptides (CTX), tartrate-resistant acid phosphatase 5b (TRAP-5b) were all increased compared to normal levels. The levels of postoperative serum iPTH, CT, CTX and TRAP-5b decreased significantly compared to preoperative levels, while the levels of OC and ALP increased significantly. Of the 115 patients, 101 (87.8%) developed HBS after PTX. High preoperative serum ALP and low preoperative serum calcium level independently predicted the occurrence of HBS. Younger preoperative age, high preoperative serum ALP and iPTH level independently predicted the severity of HBS. CONCLUSIONS: In severe SHPT, both bone formation and resorption were active, which suggested the presence of high-turnover bone diseases characterized by up-regulation of osteoclasts-osteoblasts functionally coupling activation in the patients. PTX could promote osteoblast activity and reduce osteoclast activity. HBS was common after PTX. Preoperative higher serum ALP and lower calcium were independent predictors of the occurrence of HBS. Younger patients with higher preoperative ALP and PTH may need to closely monitor serum calcium levels and intensive calcium supplementation after PTX.

Protective Effects of Moderate Ca Supplementation against Cd-Induced Bone Damage under Different Population-Relevant Doses in Young Female Rats.

Estimation of the skeleton-protective effects of Ca in Cd-induced bone damage is helpful in the assessment of Cd health risk. The aim of this study was to identify whether Ca supplementation during exposure to different population-relevant doses of Cd can prevent Cd-induced bone damage under the tolerable upper intake level of Ca supplementation. Young female Sprague-Dawley rats were given different population-relevant doses of Cd (1, 5, and 50 mg Cd/kg diet) and Ca supplementation (0.4% Ca supplementation) intervention. Ca supplementation significantly decreased Cd-induced bone microstructure damage, increased bone biomechanics (p < 0.05), serum bone formation marker level (p < 0.05) and expression of osteogenic gene markers exposure to the 5 and 50 mg Cd/kg diets. However, it had no impact on these indicators under the 1 mg Cd/kg diets, with the exception of expression of osteogenic marker genes. Ca supplementation significantly decreased serum Klotho level (p < 0.05), and fibroblast growth factor 23/Klotho-associated gene expression in the kidney and bone showed significant changes. In conclusion, Ca supplementation has a positive effect on bone formation and bone quality against the damaging impact of Cd, especially with exposure to the 5 mg and 50 mg Cd/kg diet, which may be related to its impact on the fibroblast growth factor 23/Klotho axis.

Biophysical stimulation of bone and cartilage: state of the art and future perspectives.

INTRODUCTION: Biophysical stimulation is a non-invasive therapy used in orthopaedic practice to increase and enhance reparative and anabolic activities of tissue. METHODS: A sistematic web-based search for papers was conducted using the following titles: (1) pulsed electromagnetic field (PEMF), capacitively coupled electrical field (CCEF), low intensity pulsed ultrasound system (LIPUS) and biophysical stimulation; (2) bone cells, bone tissue, fracture, non-union, prosthesis and vertebral fracture; and (3) chondrocyte, synoviocytes, joint chondroprotection, arthroscopy and knee arthroplasty. RESULTS: Pre-clinical studies have shown that the site of interaction of biophysical stimuli is the cell membrane. Its effect on bone tissue is to increase proliferation, synthesis and release of growth factors. On articular cells, it creates a strong A2A and A3 adenosine-agonist effect inducing an anti-inflammatory and chondroprotective result. In treated animals, it has been shown that the mineralisation rate of newly formed bone is almost doubled, the progression of the osteoarthritic cartilage degeneration is inhibited and quality of cartilage is preserved. Biophysical stimulation has been used in the clinical setting to promote the healing of fractures and non-unions. It has been successfully used on joint pathologies for its beneficial effect on improving function in early OA and after knee surgery to limit the inflammation of periarticular tissues. DISCUSSION: The pooled result of the studies in this review revealed the efficacy of biophysical stimulation for bone healing and joint chondroprotection based on proven methodological quality. CONCLUSION: The orthopaedic community has played a central role in the development and understanding of the importance of the physical stimuli. Biophysical stimulation requires care and precision in use if it is to ensure the success expected of it by physicians and patients.

Updating the role of matrix metalloproteinases in mineralized tissue and related diseases

Abstract Bone development and healing processes involve a complex cascade of biological events requiring well-orchestrated synergism with bone cells, growth factors, and other trophic signaling molecules and cellular structures. Beyond health processes, MMPs play several key roles in the installation of heart and blood vessel related diseases and cancer, ranging from accelerating metastatic cells to ectopic vascular mineralization by smooth muscle cells in complementary manner. The tissue inhibitors of MMPs (TIMPs) have an important role in controlling proteolysis. Paired with the post-transcriptional efficiency of specific miRNAs, they modulate MMP performance. If druggable, these molecules are suggested to be a platform for development of "smart" medications and further clinical trials. Thus, considering the pleiotropic effect of MMPs on mammals, the purpose of this review is to update the role of those multifaceted proteases in mineralized tissues in health, such as bone, and pathophysiological disorders, such as ectopic vascular calcification and cancer.

Intestinal Phosphorus Absorption in Chronic Kidney Disease.

Chronic kidney disease (CKD) affects approximately 10% of adults worldwide. Dysregulation of phosphorus homeostasis which occurs in CKD leads to development of CKD-Mineral Bone Disorder (CKD-MBD) and contributes to increased morbidity and mortality in these patients. Phosphorus is regulated by multiple hormones (parathyroid hormone (PTH), 1,25-dihyxdroxyvitamin D (1,25D), and fibroblast growth factor 23 (FGF23)) and tissues (kidney, intestine, parathyroid glands, and bone) to maintain homeostasis. In health, the kidneys are the major site of regulation for phosphorus homeostasis. However, as kidney function declines, the ability of the kidneys to adequately excrete phosphorus is reduced. The hormonal changes that occur with CKD would suggest that the intestine should compensate for impaired renal phosphorus excretion by reducing fractional intestinal phosphorus absorption. However, limited studies in CKD animal models and patients with CKD suggest that there may be a break in this homeostatic response where the intestine fails to compensate. As many existing therapies for phosphate management in CKD are aimed at reducing absolute intestinal phosphorus absorption, better understanding of the factors that influence fractional and absolute absorption, the mechanism by which intestinal phosphate absorption occurs, and how CKD modifies these is a much-needed area of study.

Evidence for Bone and Mineral Metabolism Alterations in Children With Autosomal Dominant Polycystic Kidney Disease.

Context: Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. Hypophosphatemia was demonstrated in adult patients with preserved renal function, together with high fibroblast growth factor 23 (FGF23) and low soluble Klotho levels. The latter explained the relative FGF23 hyporesponsiveness in this cohort. Objective: Evaluating phosphate and bone mineral metabolism in children with ADPKD compared with what is known in adult ADPKD patients. Design: Observational cross-sectional study. Setting: Multicenter study via ambulatory care in tertiary centers. Participants: Ninety-two children with ADPKD (52 males; mean ± standard deviation age, 10.2 ± 5.0 years) and 22 healthy controls (HCs, 10 males; mean ± standard deviation age, 10.3 ± 4.1 years). Main Outcome Measures: The predictor was early ADPKD stage. Bone mineral metabolism and renal phosphate handling were the main outcome measures. Performed measurements were serum phosphate, tubular maximum phosphorus reabsorption per glomerular filtration rate, FGF23, soluble Klotho, sclerostin, and bone alkaline phosphatase. Results: ADPKD children had significantly lower serum phosphate levels compared with HC. Low tubular maximum phosphorus reabsorption per glomerular filtration rate was observed in 24% of patients, although not significantly different from HC. Serum FGF23 and soluble Klotho levels were comparable between patients and HC. In addition, we showed decreased bone alkaline phosphatase levels in ADPKD children, suggesting suppressed bone formation. Conclusions: This report demonstrates hypophosphatemia and suppressed bone formation in a pediatric ADPKD cohort, with preserved renal function, compared with HC. Although FGF23 levels were not different from controls, they should be considered inappropriate, given the concomitant hypophosphatemia. Further studies are required to elucidate underlying pathophysiology and potential clinical consequences.

Bone remodeling and regulating biomarkers in women at the time of breast cancer diagnosis.

PURPOSE: The majority of breast cancer patients receive endocrine therapy, including aromatase inhibitors known to cause increased bone resorption. Bone-related biomarkers at the time of breast cancer diagnosis may predict future risk of osteoporosis and fracture after endocrine therapy. METHODS: In a large population of 2,401 female breast cancer patients who later underwent endocrine therapy, we measured two bone remodeling biomarkers, TRAP5b and BAP, and two bone regulating biomarkers, RANKL and OPG, in serum samples collected at the time of breast cancer diagnosis. We analyzed these biomarkers and their ratios with patients' demographic, lifestyle, clinical tumor characteristics, as well as bone health history. RESULTS: The presence of bone metastases, prior bisphosphonate (BP) treatment, and blood collection after chemotherapy had a significant impact on biomarker levels. After excluding these cases and controlling for blood collection time, several factors, including age, race/ethnicity, body mass index, physical activity, alcohol consumption, smoking, and hormonal replacement therapy, were significantly associated with bone biomarkers, while vitamin D or calcium supplements and tumor characteristics were not. When prior BP users were included in, recent history of osteoporosis and fracture was also associated. CONCLUSIONS: Our findings support further investigation of these biomarkers with bone health outcomes after endocrine therapy initiation in women with breast cancer.

Comparison of the effects of novel vitamin D receptor analog VS-105 and paricalcitol on chronic kidney disease-mineral bone disorder in an experimental model of chronic kidney disease.

When using vitamin D, the most important clinical problems are hypercalcemia, hyperphosphatemia, and vascular calcification. VS-105 is a novel vitamin D receptor (VDR) analog. In the present study, we compared the effects of VS-105 and paricalcitol on chronic kidney disease-mineral bone disorder (CKD-MBD) in a CKD rat model. We used male Sprague-Dawley (SD) rats and performed 5/6 nephrectomy at 8-9 weeks. At 10 weeks, the rats were classified into five groups and administered vehicle, low-dose paricalcitol (LP, 0.1µg/kg), high-dose paricalcitol (HP, 0.3µg/kg), low-dose VS-105 (LV, 0.2µg/kg), and high-dose VS-105 (HV, 0.6 µg/kg) three times a week for 10 weeks. There were no significant differences in blood pressure or renal function among the five groups. Alhough serum calcium levels were comparable between the LP and LV groups, they were higher in the HP group than in the HV group. Serum phosphate levels were higher in the paricalcitol-treated groups than in the VS-105-treated groups and paticularly higher in the HP group than in the other groups. The urinary excretion of phosphate was greater in the VS-105-treated groups than in the paricalcitol-treated groups. Serum parathyroid hormone (PTH) levels decreased and serum fibroblast growth factor-23 (FGF23) levels were elevated after administering paricalcitol and VS-105; however, serum FGF23 levels were remarkably elevated in the paricalcitol-treated groups. Further biochemical analyses revealed that the calcium content of the aorta was higher in the paricalcitol-treated groups than in the VS-105-treated group. VDR and Klotho expression in the kidney was significantly higher in the VS-105-treated groups than in the paricalcitol-treated groups although both agents increased these expressions. Our data suggest that VS-105 had a lesser effect on CKD-MBD than paricalcitol except in the case of serum PTH levels. The mechanism appears to be associated with the difference in VDR and Klotho expression.

Mineral bone disorder and its management among hemodialysis patients in the Gulf Cooperation Council: Initial findings from the dialysis outcomes and practice patterns study (2012-2015).

The prospective cohort Dialysis Outcomes and Practice Patterns Study (DOPPS) initiated data collection in national samples of hemodialysis (HD) units (total of 41 study sites) in all six Gulf Cooperation Council (GCC) countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates) in late 2012. Here, we report initial results regarding mineral bone disorders (MBDs) and its management in the GCC countries. Forty-one randomly selected HD facilities, treating >23 HD patients each, were sampled and represent care for >95% of GCC HD patients. Descriptive results for the GCC countries based on a random sample of 20-30 HD patients in each study facility. Initial results for the GCC are from 931 HD patients treated at 41 dialysis units (ranging from 1 unit in Bahrain to 21 in Saudi Arabia). Results are presented as weighted estimates, accounting for the sampling fraction in each unit. Baseline descriptive statistics (e.g., mean, median, or percentage), weighted by facility sampling fraction were calculated for the study sample. For analyses examining the percent of facility patients having (a) serum phosphorus >6.0 mg/dL or (b) parathyroid hormone (PTH) >600 pg/mL, analyses were restricted to facilities having at least 10 HD patients with a reported serum phosphorus or PTH measurement, respectively. Logistic regression analyses of the indicated binary outcomes were based on the use of generalized estimating equations and were adjusted for GCC country, patient age category (<45 years, 45-65 years, and >65 years old), sex, and whether the patient was diagnosed with diabetes mellitus. Logistic models accounted for clustering of patients within facilities, assuming an exchangeable working correlation matrix. Mean age of HD patients in the GCC countries was 53 years vs. 61-64 years in the three other DOPPS regions. MBD markers showed slightly lower mean serum Calcium in the GCC countries, similar mean serum phosphorus, and intermediate median PTH levels compared with the three other DOPPS regions. Among GCC countries, the country mean value of MBD markers ranged from 8.6-9.0 mg/dL for serum calcium, 4.4-5.4 mg/dL for serum phosphorus, whereas median PTH ranged from 163-389 pg/mL. Similar to other DOPPS regions, PTH was higher among patients who were younger or without diabetes, and serum phosphorus was lower with older age (P <0.001 for each). History of parathyroidectomy was lower in the GCC countries versus other regions but did not differ when adjusted for age and dialysis vintage. Among treatments used for managing MBD, the GCC countries showed one of the highest uses of cinacalcet (24%) and phosphorus binder use (81%), whereas intravenous Vitamin D use (24%) was slightly higher than that in EURANZ. A much larger fraction of HD patients in the GCC countries had a dialysate calcium bath ≥3.5 mEq/L (43%) versus 0-4% in the three other DOPPS regions. Although many aspects of MBD management and MBD marker achievement are similar in the GCC countries to that seen in other DOPPS study regions, large variability was seen across countries and facilities in the GCC. Mean serum calcium was lower in the GCC despite the much greater use of dialysate Ca of ~3.5 mEq/L which may be due to the relatively low use of vitamin D and higher cinacalcet use, meriting further study. Future work will focus on GCC facility HD practices and patient characteristics most strongly related to the achievement of MBD target levels and associated outcomes.

Crucial Role of Vitamin D in the Musculoskeletal System.

Vitamin D is well known to exert multiple functions in bone biology, autoimmune diseases, cell growth, inflammation or neuromuscular and other immune functions. It is a fat-soluble vitamin present in many foods. It can be endogenously produced by ultraviolet rays from sunlight when the skin is exposed to initiate vitamin D synthesis. However, since vitamin D is biologically inert when obtained from sun exposure or diet, it must first be activated in human beings before functioning. The kidney and the liver play here a crucial role by hydroxylation of vitamin D to 25-hydroxyvitamin D in the liver and to 1,25-dihydroxyvitamin D in the kidney. In the past decades, it has been proven that vitamin D deficiency is involved in many diseases. Due to vitamin D's central role in the musculoskeletal system and consequently the strong negative impact on bone health in cases of vitamin D deficiency, our aim was to underline its importance in bone physiology by summarizing recent findings on the correlation of vitamin D status and rickets, osteomalacia, osteopenia, primary and secondary osteoporosis as well as sarcopenia and musculoskeletal pain. While these diseases all positively correlate with a vitamin D deficiency, there is a great controversy regarding the appropriate vitamin D supplementation as both positive and negative effects on bone mineral density, musculoskeletal pain and incidence of falls are reported.

Morbidities in non-transfusion-dependent thalassemia.

Patients with non-transfusion-dependent thalassemia (NTDT) experience a wide array of clinical complications despite their independence from frequent, regular red blood cell (RBC) transfusions. According to the current understanding of NTDT, these clinical complications stem from the interaction of multiple pathophysiological factors: ineffective erythropoiesis, iron overload, and hypercoagulability. The state of chronic anemia and hypoxia-resulting from ineffective erythropoiesis and hemolysis-leads to the expansion of the erythroid marrow and extramedullary hematopoiesis. The chronic ineffective erythropoiesis also triggers increased intestinal iron absorption and deposition in the liver and endocrine glands despite the lack of transfusional iron load. Patients with NTDT also have a higher incidence of thromboembolic disease, pulmonary hypertension, and silent cerebral ischemia. The treatment of NTDT relies on occasional or more frequent blood transfusions for certain indications (severe infection, pregnancy, and surgery), iron chelation therapy, splenectomy, and hydroxyurea. Splenectomy is no longer routinely performed in all patients with NTDT in light of its association with increased risk of NTDT-related complications. This review focuses on the clinical morbidities associated with NTDT, summarizes the mainstays of treatment, and sheds light on future therapeutic directions in the field.

Targeted Delivery Systems for Molecular Therapy in Skeletal Disorders.

Abnormalities in the integral components of bone, including bone matrix, bone mineral and bone cells, give rise to complex disturbances of skeletal development, growth and homeostasis. Non-specific drug delivery using high-dose systemic administration may decrease therapeutic efficacy of drugs and increase the risk of toxic effects in non-skeletal tissues, which remain clinical challenges in the treatment of skeletal disorders. Thus, targeted delivery systems are urgently needed to achieve higher drug delivery efficiency, improve therapeutic efficacy in the targeted cells/tissues, and minimize toxicities in non-targeted cells/tissues. In this review, we summarize recent progress in the application of different targeting moieties and nanoparticles for targeted drug delivery in skeletal disorders, and also discuss the advantages, challenges and perspectives in their clinical translation.

Effects of low level laser therapy on inflammatory and angiogenic gene expression during the process of bone healing: A microarray analysis.

The process of bone healing as well as the expression of inflammatory and angiogenic genes after low level laser therapy (LLLT) were investigated in an experimental model of bone defects. Sixty Wistar rats were distributed into control group and laser group (830nm, 30mW, 2,8J, 94seg). Histopathological analysis showed that LLLT was able to modulate the inflammatory process in the area of the bone defect and also to produce an earlier deposition of granulation tissue and newly formed bone tissue. Microarray analysis demonstrated that LLLT produced an up-regulation of the genes related to the inflammatory process (MMD, PTGIR, PTGS2, Ptger2, IL1, 1IL6, IL8, IL18) and the angiogenic genes (FGF14, FGF2, ANGPT2, ANGPT4 and PDGFD) at 36h and 3days, followed by the decrease of the gene expression on day 7. Immunohistochemical analysis revealed that the subjects that were treated presented a higher expression of COX-2 at 36h after surgery and an increased VEGF expression on days 3 and 7 after surgery. Our findings indicate that LLLT was efficient on accelerating the development of newly formed bone probably by modulating the inflammatory and angiogenic gene expression as well as COX2 and VEGF immunoexpression during the initial phase of bone healing.