Oral administration of melatonin increases plasma calcium and magnesium and improves bone metabolism in aged male mice

We previously reported that the oral administration of melatonin from 4 to 20 months to male mice improved femoral bone strength and bone density during the aging. Additionally, melatonin receptor, MT2, was immunologically detected in both osteoblasts and osteoclasts of the mouse femoral bone. Thus, melatonin can act on both osteoblasts and osteoclasts to maintain bone strength during the aging process. Here, we analyzed plasma calcium (Ca2+), magnesium (Mg2+), and inorganic phosphorus ([PO4]3-) in 20-month-old male mice with or without administration melatonin (15-20 mg/kg/day) in drinking water. We found that plasma Ca2+ and Mg2+ levels in melatonin-treated mice increased significantly as compared with control mice. In [PO4]3-, melatonin administration tended to increase its plasma level, but did not reach statistical significance. The potential association between these divalent ions and metabolism markers of femoral bone was also examined. In the femoral diaphysis, the plasma Ca2+ and Mg2+ concentrations were positively correlated with periosteal and endosteal circumference which were significantly associated with the Strength Strain Index. Therefore, melatonin treatment enlarged femoral diaphysis and enhanced bone strength by increasing mineral depositions. In addition, the plasma melatonin levels were significantly positive correlation with total bone density and critical thickness in the femoral diaphysis. Since we had not observed the primary trabecular bone and osteoclasts in 20-month-old mice previously, it is suggested that plasma Ca2+ and Mg2+ are not elevated due to bone resorption. The increased plasma Ca2+ and Mg2+ by melatonin may originate from the intestinal absorption of these ions since melatonin binds to the vitamin D3 receptor, its activation is known to promote the intestinal absorption of Ca2+.

Femoral defects in revision hip arthroplasty: a therapy-oriented classification

Introduction The complex field of femoral defects in revision hip arthroplasty displays a lack of standardized, intuitive pre- and intraoperative assessment. To address this issue, the femoral defect classification (FDC) is introduced to offer a reliable, reproducible and an intuitive classification system with a clear therapeutic guideline. Materials and methods The FDC is based on the integrity of the main femoral segments which determine function and structural support. It focuses on the femoral neck, the metaphysis consisting of the greater and lesser trochanter, and the femoral diaphysis. The four main categories determine the location of the defect while subcategories a, b and c are being used to classify the extent of damage in each location. In total, 218 preoperative radiographs were retrospectively graded according to FDC and compared to intraoperatively encountered bone defects. To account for inter-rater and intra-rater agreement, 5 different observers evaluated 80 randomized cases at different points in time. Results A Cohens kappa of 0.832 ± 0.028 could be evaluated, accounting for excellent agreement between preoperative radiographs and intraoperative findings. To account for inter-rater reliability, 80 patients have been evaluated by 5 different observers. Testing for inter-rater reliability, a Fleiss Kappa of 0.688 could be evaluated falling into the good agreement range. When testing for intra-rater reliability, Cohens Kappa of each of the 5 raters has been analyzed and the mean was evaluated at 0.856 accounting for excellent agreement. Conclusion The FDC is a reliable and reproducible classification system. It combines intuitive use and structured design and allows for consistent preoperative planning and intraoperative guidance. A therapeutic algorithm has been created according to current literature and expert opinion. Due to the combination of the FDC with the recently introduced Acetabular Defect Classification (ADC) a structured approach to the entire field of hip revision arthroplasty is now available.

Rhizoma Drynariae protects against Canaglifloxacin induced bone loss

Osteoporosis is a condition marked by a loss of bone mass and degradation of the bone microstructure, both of which lead to increased fragility and consequent fragility fractures, particularly in the elderly. Rhizoma Drynariae (DRE) is one of the most often used herbal remedies for osteoporosis therapy. Transdermal drug administration is a well- established new method for drug delivery that offers numerous benefits over conventional routes. Wistar albino rats were split into five groups of six rats each: vehicle control, diabeticgroup, DRE group, Canagliflozin (CGF), and CGF + DRE group. Each medication was given by gastric gavage once a day for 35 days. The drug canagliflozin appears to raise the risk of fractur. When compared to the control group, DRE treatment increased bone strength at the femoral diaphysis in osteoporotic fractures in rats by increasing ultimate load and stiffness. The goal of this study is to investigate the anti-osteoporosis effects of DRE in diabetic rats co-treated with CGF. Blood glucose levels and bone mineral density (BMD) were measured. According to the data, DRE produced a significant increase in bone amount. DRE may help prevent and cure diabetic osteoporosis by increasing bone mineral density, according to one study. Keywords: Rhizoma Drynariae Diabetic osteoporosis, Streptozotocin induced diabetes, Canagliflozin

Time course of lymphocyte profile after femoral bone fracture

Isolated fractures of femur account for more than 10% of all road traffic injuries. Traumatic injury of femoral bone triggers a cascade of interrelated neuroendocrine reactions at systemic level, primarily at the hypothalamic-pituitary-adrenal axis, systemic response of immune system, initiated by release of tissue degradation products, cytokines and other mediators of damage into systemic blood circulation. Specific cellular reactions in response to traumatic injury to bone tissue include both innate and adaptive immune responses. In this regard, there is still scarce information on changes in blood lymphocyte subpopulations observed after closed isolated fracture of the femoral diaphysis at the middle third, before and after surgery. The aim of the present study was to evaluate the subpopulations of peripheral blood lymphocytes following closed isolated fracture of the femoral diaphysis with bone displacement in thecourse dynamics of surgical treatment, thus being required for studies in pathogenesis, development of diagnostic criteria and creating innovative treatment approaches. The study included 20 apparently healthy men and 36 men with closed isolated fracture of the femoral diaphysis of the middle third (32A and 32B, by AO/ASIF clinical classification, coded according to ICD-10 S72.3). The exclusion criteria were as follows: exacerbation of chronic comorbidities, diseases of lymphatic system and haematopoietic organs, oncological diseases, and evidence of osteoporosis. The spectrum of blood lymphocyte subsets was assessed on days 5, 7 (immediately after surgery) and on day 18 after closed isolated fracture of femoral diaphysis. We have found that, on the day 5 after IPBC along with leukocytosis in peripheral blood, the number of T-regulatory cells, cells with markers of early (CD25+) and late activation (HLA-DR+) proved to be increased, whereas representation of NK cells was decreased. On the day 7 after IPBC and immediately after surgery, leukocytosis persisted in blood, along with increased number of T-regulatory cells, CD3+ cells with early and late activation markers. On the day 18 after closed isolated fracture of the femoral diaphysis, the total numbers of leukocytes, T-lymphocytes, T-helpers, T-regulatory cells, T cells with an early activation marker are restored in peripheral blood, whereas the number of T-lymphocytes expressing HLA-DR+ molecules showed a significant increase.

Paracrine Kynurenic Pathway Activation in the Bone of Young Uremic Rats Can Antagonize Anabolic Effects of PTH on Bone Turnover and Strength through the Disruption of PTH-Dependent Molecular Signaling

Secondary hyperparathyroidism and abnormalities in tryptophan (TRP) metabolism are commonly observed in chronic kidney disease (CKD). The present study aimed to establish potential interactions between endogenous parathyroid hormone (PTH) and activation of the bone kynurenine (KYN) pathway in relation to bone turnover and strength in young rats after one month (CKD-1) and three months (CKD-3) of experimental CKD. TRP, KYN, KYN/TRP ratio and bone turnover markers (BTMs) were measured in trabecular and cortical bone tissue. Expression of aryl hydrocarbon receptor (AhR) and the genes involved in osteogenesis was determined in femoral bone. Biomechanical testing of femoral diaphysis and femoral neck was also performed. Activation of the KYN pathway in trabecular bone during CKD development intensified the expression of genes related to osteogenesis, which led to a decrease in cyclic adenosine monophosphate (cAMP) and BTMs levels, resulting in a stiffer and mechanically weaker femoral neck. In contrast, reduction of the KYN pathway in cortical bone allowed to unblock the PTH-dependent anabolic activating transcription factor 4/parathyroid hormone 1 receptor (PTH1R/ATF4) axis, led to cAMP accumulation, better bone turnover and strength in the course of CKD development. In summary, the paracrine KYN pathway in bone can interfere with the anabolic effects of PTH on bone through disrupting PTH-dependent molecular signaling.