Surgical Considerations for Osteoporosis, Osteopenia, and Vitamin D Deficiency in Upper Extremity Surgery.

Fragility fractures as a result of osteoporosis, osteopenia, or vitamin D deficiency are some of the most common injuries encountered in orthopedics and require careful consideration when determining the appropriate management and treatment options. A thorough perioperative evaluation can identify causes of low bone mineral density allowing for initiation of appropriate therapy. Surgical treatment of these fractures can be difficult, and techniques should be employed to ensure stable fixation. It is important to understand the potential pitfalls associated with treatment of fragility fractures to prevent avoidable complications. Postoperative management is key to preventing future injuries in this unique patient population.

Effect of early preventive supplementation with calcium and phosphorus on metabolic bone disease in premature infants.

OBJECTIVE: The objective was to study the effect of early preventive calcium and phosphorus supplementation on metabolic bone disease in preterm infants. METHODS: A retrospective analysis of 234 preterm infants with a gestational age < 32 weeks or birth weight < 1500 g who were hospitalized in the Neonatology Department of the Second Hospital of Shandong University from 01.2018 to 12.2020 was conducted. One hundred thirty-two premature infants hospitalized from 01.2018 to 06.2019 did not receive prophylactic calcium and phosphorus supplementation in the early postnatal period. These infants received calcium or phosphorus supplementation at the time of hypocalcaemia or hypophosphatemia diagnosis. One hundred two premature infants hospitalized from 07.2019 to 12.2020 received early preventive calcium and phosphorus supplementation after birth. The levels of serum calcium and phosphorus, alkaline phosphatase, 25-hydroxyvitamin D, calcitonin, and parathyroid hormone at different time points and growth indicators at six months of age were compared between the two groups of infants. The number of cases of metabolic bone disease and fracture between the two groups was compared. RESULTS: 1) A total of 12 infants (5.13%) among the 234 preterm infants were diagnosed with metabolic bone disease, including 2 (1.96%) in the prophylactic supplementation group and 10 (7.58%) in the nonprophylactic supplementation group. Fractures occurred in 3 premature infants (25.0%) with metabolic bone disease, all of whom were in the group that did not receive prophylactic supplementation. 2) There was no significant difference in serum calcium and calcitonin levels between the two groups. The levels of serum phosphorus and 25 hydroxyvitamin D in the prophylactic supplementation group were higher than those in the nonprophylactic supplementation group (P < 0.05). In comparison, alkaline phosphatase and parathyroid hormone levels were lower in the prophylactic supplementation group than in the nonprophylactic supplementation group (P < 0.05). Preterm infants in the prophylactic supplementation group had higher weight, length, head circumference, and bone density values than those in the nonprophylactic supplementation group (P < 0.05). CONCLUSION: Preventive supplementation with calcium and phosphorus after birth can effectively improve calcium and phosphorus metabolism, and reduce the incidence of metabolic bone disease and fractures in premature infants. This can be further publicized and used clinically.

Prevalencia de osteopenia del prematuro antes y después de la implementación de una estrategia temprana de manejo fosfocálcico / Prevalence of osteopenia of prematurity before and after implementing an early strategy with the use of calcium and phosphate

Introducción. Con el uso de la nutrición parenteral agresiva en recién nacidos de muy bajo peso, se detectaron alteraciones del metabolismo fosfocálcico. En 2016 se implementó una estrategia de prevención a través del monitoreo fosfocálcico y su suplementación temprana. El objetivo fue estudiar si esta estrategia disminuye la prevalencia de osteopenia e identificar factores de riesgo asociados. Población y métodos. Estudio cuasiexperimental que comparó la prevalencia de osteopenia entre dos grupos: uno después de implementar la estrategia de monitoreo y suplementación fosfocálcica (01/01/2017-31/12/2019), y otro previo a dicha intervención (01/01/2013-31/12/2015). Resultados. Se incluyeron 226 pacientes: 133 pertenecen al período preintervención y 93 al posintervención. La prevalencia de osteopenia global fue del 26,1 % (IC95% 20,5-32,3) y disminuyó del 29,3 % (IC95% 21,7-37,8) en el período preintervención al 21,5 % (IC95% 13,6-31,2) en el posintervención, sin significancia estadística (p = 0,19). En el análisis multivariado, el puntaje NEOCOSUR de riesgo de muerte al nacer, recibir corticoides posnatales y el período de intervención se asociaron de manera independiente a osteopenia. Haber nacido luego de la intervención disminuyó un 71 % la probabilidad de presentar fosfatasa alcalina >500 UI/L independientemente de las restantes variables incluidas en el modelo. Conclusión. La monitorización y suplementación fosfocálcica precoz constituye un factor protector para el desarrollo de osteopenia en recién nacidos con muy bajo peso al nacer.

Introduction. With the use of aggressive parenteral nutrition in very low birth weight infants, alterations in calcium and phosphate metabolism were detected. In 2016, a prevention strategy was implemented through calcium phosphate monitoring and early supplementation. Our objective was to study whether this strategy reduces the prevalence of osteopenia and to identify associated risk factors. Population and methods. Quasi-experiment comparing the prevalence of osteopenia between two groups: one after implementing the calcium phosphate monitoring and supplementation strategy (01/01/2017­12/31/2019) and another prior to such intervention (01/01/2013­12/31/2015). Results. A total of 226 patients were included: 133 in the pre-intervention period and 93 in the post-intervention period. The overall prevalence of osteopenia was 26.1% (95% CI: 20.5­32.3) and it was reduced from 29.3% (95% CI: 21.7­37.8) in the pre-intervention period to 21.5% (95% CI: 13.6­31.2) in the post-intervention period, with no statistical significance (p = 0.19). In the multivariate analysis, the NEOCOSUR score for risk of death at birth, use of postnatal corticosteroids, and the intervention period were independently associated with osteopenia. Being born after the intervention reduced the probability of alkaline phosphatase > 500 IU/L by 71%, regardless of the other variables included in the model. Conclusion. Calcium phosphate monitoring and early supplementation is a protective factor against the development of osteopenia in very low birth weight infants.

Phenolic acids prevent sex-steroid deficiency-induced bone loss and bone marrow adipogenesis in mice.

Phenolic acids, such as hippuric acid (HA) and 3-(3-hydroxyphenyl) propionic acid (3-3-PPA), can be produced from microbiome digestion of polyphenols. Previously it was found that HA and 3-3-PPA facilitate bone formation and suppress bone resorption. However, the mechanism of action by which HA and 3-3-PPA protect bone from degeneration is currently unknown. In this report, we present that HA and 3-3-PPA suppression of bone resorption is able to ameliorate bone loss in an ovariectomy (OVX) osteopenic mouse model though not to the extent of Zoledronic acid (ZA). HA and 3-3-PPA treatments were shown to significantly decrease bone marrow adipocyte-like cell formation and inhibited gene expression of key adipogenesis regulator peroxisome proliferator activated receptor gamma (PPARγ) and lipoprotein lipase (Lpl) in bone from OVX mice. In addition, ChIP experiments showed that the association between PPARγ and Lpl promoter region in preadipocyte-like cells was significantly suppressed following HA or 3-3-PPA treatment. Contrasting HA and 3-3-PPA, ZA significantly increased TRAP activity in the area close to growth plate and significantly suppressed bone cell proliferation. These data suggest that phenolics acids such as HA or 3-3-PPA may prevent bone degeneration after OVX through suppression of inflammatory milieu in the bone.

The microarchitecture and chemical composition of the femur neck of senescent female rats after different physical training protocols.

A sedentary lifestyle, coupled with a decrease in estrogen, impairs bone homeostasis, favoring to the development of osteopenia and osteoporosis, both recognized as risk factors for fractures. Here, we investigated the quality of the femur, particularly the femur neck region, and the ambulation performance of senescent rats subjected to three different physical training protocols during the periestropause period. Forty-eight female rats, 18 months of age, were subjected to a 120-day training period, three times a week. The rats were distributed into four groups: aerobic training (AT), strength training (ST), concurrent training (CT), or no training (NT). After the experimental period, at 21 months of age, ambulation performance and femur were analyzed using microtomography, Raman stereology, densitometry, and mechanical strength tests. The results demonstrated greater remodeling activity and improvement in resistance and bone microarchitecture in the femur neck of senescent female rats after undergoing physical training. Our verified higher intensities of bands related to collagen, phosphate, amide III, and amide I. Furthermore, the analysis of the secondary collagen structures indicated alterations in the collagen network due to the exercise, resulting in increased bone strength. Both AT and strength-based training proved beneficial, with AT showing greater adaptations in bone density and stiffness in the femur, while strength-based training greater adaptations in trabecular and cortical structure. These insights contribute to the understanding of the potential interventions for preventing osteopenia and osteoporosis, which are critical risk factors for fractures.

Prevalence of osteopenia of prematurity before and after implementing an early strategy with the use of calcium and phosphate. / Prevalencia de osteopenia del prematuro antes y después de la implementación de una estrategia temprana de manejo fosfocálcico.

Introduction. With the use of aggressive parenteral nutrition in very low birth weight infants, alterations in calcium and phosphate metabolism were detected. In 2016, a prevention strategy was implemented through calcium phosphate monitoring and early supplementation. Our objective was to study whether this strategy reduces the prevalence of osteopenia and to identify associated risk factors. Population and methods. Quasi-experiment comparing the prevalence of osteopenia between two groups: one after implementing the calcium phosphate monitoring and supplementation strategy (01/01/2017-12/31/2019) and another prior to such intervention (01/01/2013-12/31/2015). Results. A total of 226 patients were included: 133 in the pre-intervention period and 93 in the post-intervention period. The overall prevalence of osteopenia was 26.1% (95% CI: 20.5-32.3) and it was reduced from 29.3% (95% CI: 21.7-37.8) in the pre-intervention period to 21.5% (95% CI: 13.6-31.2) in the post-intervention period, with no statistical significance (p = 0.19). In the multivariate analysis, the NEOCOSUR score for risk of death at birth, use of postnatal corticosteroids, and the intervention period were independently associated with osteopenia. Being born after the intervention reduced the probability of alkaline phosphatase > 500 IU/L by 71%, regardless of the other variables included in the model. Conclusion. Calcium phosphate monitoring and early supplementation is a protective factor against the development of osteopenia in very low birth weight infants.

Introducción. Con el uso de la nutrición parenteral agresiva en recién nacidos de muy bajo peso, se detectaron alteraciones del metabolismo fosfocálcico. En 2016 se implementó una estrategia de prevención a través del monitoreo fosfocálcico y su suplementación temprana. El objetivo fue estudiar si esta estrategia disminuye la prevalencia de osteopenia e identificar factores de riesgo asociados. Población y métodos. Estudio cuasiexperimental que comparó la prevalencia de osteopenia entre dos grupos: uno después de implementar la estrategia de monitoreo y suplementación fosfocálcica (01/01/2017-31/12/2019), y otro previo a dicha intervención (01/01/2013-31/12/2015). Resultados. Se incluyeron 226 pacientes: 133 pertenecen al período preintervención y 93 al posintervención. La prevalencia de osteopenia global fue del 26,1 % (IC95% 20,5-32,3) y disminuyó del 29,3 % (IC95% 21,7-37,8) en el período preintervención al 21,5 % (IC95% 13,6-31,2) en el posintervención, sin significancia estadística (p = 0,19). En el análisis multivariado, el puntaje NEOCOSUR de riesgo de muerte al nacer, recibir corticoides posnatales y el período de intervención se asociaron de manera independiente a osteopenia. Haber nacido luego de la intervención disminuyó un 71 % la probabilidad de presentar fosfatasa alcalina >500 UI/L independientemente de las restantes variables incluidas en el modelo. Conclusión. La monitorización y suplementación fosfocálcica precoz constituye un factor protector para el desarrollo de osteopenia en recién nacidos con muy bajo peso al nacer.

Prenatal and Neonatal Bone Health: Updated Review on Early Identification of Newborns at High Risk for Osteopenia.

Bone health starts with maternal health and nutrition, which influences bone mass and density already in utero. The mechanisms underlying the effect of the intrauterine environment on bone health are partly unknown but certainly include the 'foetal programming' of oxidative stress and endocrine systems, which influence later skeletal growth and development. With this narrative review, we describe the current evidence for identifying patients with risk factors for developing osteopenia, today's management of these populations, and screening and prevention programs based on gestational age, weight, and morbidity. Challenges for bone health prevention include the need for new technologies that are specific and applicable to pregnant women, the foetus, and, later, the newborn. Radiofrequency ultrasound spectrometry (REMS) has proven to be a useful tool in the assessment of bone mineral density (BMD) in pregnant women. Few studies have reported that transmission ultrasound can also be used to assess BMD in newborns. The advantages of this technology in the foetus and newborn are the absence of ionising radiation, ease of use, and, above all, the possibility of performing longitudinal studies from intrauterine to extrauterine life. The use of these technologies already in the intrauterine period could help prevent associated diseases, such as osteoporosis and osteopenia, which are characterised by a reduction in bone mass and degeneration of bone structure and lead to an increased risk of fractures in adulthood with considerable social repercussions for the related direct and indirect costs.

Zoledronic acid after spinal cord injury mitigates losses in proximal femoral strength independent of ambulation ability.

Rapid bone loss can occur after spinal cord injury (SCI) and a standard of care to prevent or treat this phenomenon is an active area of research. Using advanced analysis techniques, this study demonstrates that zoledronic acid, a possible treatment, prevented loss of bone strength at the hip following SCI. INTRODUCTION: Bone loss below the level of neurological lesion is a well-known complication of spinal cord injury (SCI), and effective preventive treatment for this phenomenon is an active area of research. Zoledronic acid has demonstrated efficacy to attenuate bone loss at the hip after SCI, but previous studies relied on measurements from dual-energy X-ray absorptiometry. The purpose of this investigation was to more thoroughly characterize changes to bone mineral and strength at the proximal femur in individuals receiving zoledronic acid in the acute SCI stage; we also examined the influence of ambulatory ability on bone outcomes. METHODS: Participants randomized to either zoledronic acid (n = 29) or placebo (n = 30) received computed tomography (CT) scans and ambulatory assessments at baseline and 6 and 12 months following drug infusion. CT-based finite element (FE) modeling was used to predict changes in proximal femoral strength associated with treatment. RESULTS: After 12 months, FE-predicted bone strength was reduced by a mean (SD) of 9.6 (17.9)% in the zoledronic acid group versus 24.6 (24.5)% in the placebo group (p = 0.007). These differences in strength were explained by reductions in CT measurements of both trabecular (p < 0.001) and cortical (p ≤ 0.021) bone at the femoral neck and trochanteric region. Ambulation ability influenced select trabecular and cortical parameters, but we were unable to detect an impact on FE-predicted bone strength. CONCLUSION: These findings demonstrate that treatment with zoledronic acid in acute SCI attenuates losses in proximal femoral strength, which may reduce the risk of hip fractures across patients with varying degrees of ambulatory abilities.

Nicotinamide mononucleotide supplementation mitigates osteopenia induced by modeled microgravity in rats.

Exposure to weightlessness causes severe osteopenia, resulting in raised fracture risk. The current study aimed to investigate whether nicotinamide mononucleotide (NMN) supplementation protected against the osteopenia in hindlimb unloading (HLU) rats in vivo and modeled microgravity-induced osteoblastic dysfunction in vitro. The 3-mo-old rats were exposed to HLU and intragastrically administered NMN every 3 days (500 mg/kg body weight) for 4 weeks. NMN supplementation mitigated HLU-induced bone loss, evidenced by greater bone mass and biomechanical properties and better trabecular bone structure. NMN supplementation mitigated HLU-induced oxidative stress, evidenced by greater levels of nicotinamide adenine dinucleotide and activities of superoxide dismutase 2 and lesser malondialdehyde levels. Modeled microgravity stimulation using rotary wall vessel bioreactor in MC3T3-E1 cells inhibited osteoblast differentiation, which was reversed by NMN treatment. Furthermore, NMN treatment mitigated microgravity-induced mitochondrial impairments, evidenced by lesser reactive oxygen species generation and greater adenosine triphosphate production, mtDNA copy number, and activities of superoxide dismutase 2 and Complex I and II. Additionally, NMN promoted activation of AMP-activated protein kinase (AMPK), evidenced by greater AMPKα phosphorylation. Our research suggested that NMN supplementation attenuated osteoblastic mitochondrial impairment and mitigated osteopenia induced by modeled microgravity.

A low-intensity lifelong exercise routine changes miRNA expression in aging and prevents osteosarcopenic obesity by modulating inflammation.

Osteosarcopenic obesity (OSO) has been associated with increase immobility, falls, fractures, and other dysfunctions, which could increase mortality risk during aging. However, its etiology remains unknown. Recent studies revealed that sedentarism, fat gain, and epigenetic regulators are critical in its development. One effective intervention to prevent and treat OSO is exercise. Therefore, in the present study, by keeping rats in conditions of sedentarism and others under a low-intensity exercise routine, we established an experimental model of OSO. We determined the degree of sarcopenia, obesity, and osteopenia at different ages and analyzed the miRNA expression during the lifespan using miRNA microarrays from gastrocnemius muscle. Interestingly microarrays results showed that there is a set of miRNAs that changed their expression with exercise. The pathway enrichment analysis showed that these miRNAs are strongly associated with immune regulation. Further inflammatory profiles with IL-6/IL-10 and TNF-α/IL-10 ratios showed that exercised rats presented a lower pro-inflammatory profile than sedentary rats. Also, the body fat gain in the sedentary group increased the inflammatory profile, ultimately leading to muscle dysfunction. Exercise prevented strength loss over time and maintained skeletal muscle functionality over time. Differential expression of miRNAs suggests that they might participate in this process by regulating the inflammatory response associated with aging, thus preventing the development of OSO.

Moxibustion as adjuvant therapy for preventing bone loss in postmenopausal women: protocol for a randomised controlled trial.

INTRODUCTION: Postmenopausal osteoporosis, caused by ageing and oestrogen deficiency, seriously threatens women's physical and mental health. Postmenopausal osteopenia is the transition from healthy bone to osteoporosis, and it may be the key period for preventing bone loss. Moxibustion, a physical therapy of Traditional Chinese Medicine, has potential benefits for osteoporosis treatment and prevention, but it has not been adequately studied. This study aims to explore the clinical effects and safety of moxibustion in delaying bone loss in postmenopausal women. METHODS AND ANALYSIS: In this parallel-design, randomised, patient-blind and assessor-blind, controlled clinical study, 150 women with osteopenia at low fracture risk will be randomly assigned to a moxibustion treatment (MT) group or a placebo-moxibustion control (PMC) group in a 1:1 ratio. In addition to the fundamental measures (vitamin D3 and calcium) as recommended by the guidelines, participants of the two groups will receive MT or PMC treatment for 42 sessions over 12 months. The primary outcome will be the bone mineral density (BMD) of the lumbar spine at the end of the 12-month treatment, and secondary outcomes will be the BMD of the femoral neck and total hip, T-scores, bone turnover markers, serum calcium levels, serum magnesium levels, serum phosphorus levels, serum parathyroid hormone levels and 25-hydroxyvitamin D levels, intensity of bone pain, quality of life, incidence of osteoporosis and fractures, usage of emergency drugs or surgery, participant self-evaluation of therapeutic effects and the rate of adverse events. All statistical analyses will be performed based on the intention-to-treat and per-protocol principle. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the Ethics Committee on Biomedical Research, West China Hospital of Sichuan University (permission number: 2021-1243). The results are expected to be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ChiCTR2100053953.

Don't Forget the Bones: Incidence and Risk Factors of Metabolic Bone Disease in a Cohort of Preterm Infants.

Metabolic bone disease of prematurity (MBD) is a condition of reduced bone mineral content (BMC) compared to that expected for gestational age (GA). Preterm birth interrupts the physiological process of calcium (Ca) and phosphorus (P) deposition that occurs mostly in the third trimester of pregnancy, leading to an inadequate bone mineralization during intrauterine life (IUL). After birth, an insufficient intake of Ca and P carries on this alteration, resulting in overt disease. If MBD is often a self-limited condition, in some cases it could hesitate the permanent alteration of bone structures with growth faltering and failure to wean off mechanical ventilation due to excessive chest wall compliance. Despite advances in neonatal intensive care, MBD is still frequent in preterm infants, with an incidence of 16−23% in very-low-birth-weight (VLBW, birth weight <1500 g) and 40−60% in extremely low-birth-weight (ELBW, birth weight <1000 g) infants. Several risk factors are associated with MBD (e.g., malabsorption syndrome, parenteral nutrition (PN), pulmonary bronchodysplasia (BPD), necrotizing enterocolitis (NEC), and some chronic medications). The aim of this study was to evaluate the rate of MBD in a cohort of VLBWI and the role of some risk factors. We enrolled 238 VLBWIs (107 male). 52 subjects were classified as increased risk (G1) and 186 as standard risk (G2) according to serum alkaline phosphatase (ALP) and phosphorus (P) levels. G1 subjects have lower GA (p < 0.01) and BW (p < 0.001). Moreover, they need longer PN support (p < 0.05) and invasive ventilation (p < 0.01). G1 presented a higher rate of BPD (p = 0.026). At linear regression analysis, BW and PN resulted as independent predictor of increased risk (p = 0.001, p = 0.040, respectively). Preventive strategies are fundamental to prevent chronic alteration in bone structures and to reduce the risk of short stature. Screening for MBD based on serum ALP could be helpful in clinical practice to identify subjects at increased risk.

Incidence of Metabolic Bone Disease After Implementation of Bone Protective Nutritional Strategies: A Prospective Cohort Study.

BACKGROUND: Metabolic bone disease (MBD) is a morbidity of multifactorial etiology with a high incidence in very preterm infants. We planned to study the incidence of MBD after implementation of bone health focussed nutritional strategy (BNS) in those <30 weeks gestation at birth. METHODS: This prospective cohort study including preterm newborns (<30 weeks) who received nutrition that incorporated (a) Early initiation of intravenous potassium phosphate; (b) Early enteral supplementation with multicomponent human milk fortifier at enteral feed tolerance of 40 mL/kg/day feeds itself; and (c) Weekly phosphorus measurements with optimization of enteral intakes. Incidence of MBD at 4 weeks of postnatal age and beyond were analyzed. Other relevant safety and clinical outcomes were measured. RESULTS: Of the 67 included neonates receiving BNS, 20.9% were classified as MBD. There was a low rate of hyper-phosphatemia (4.5%) and hyperkalemia (2.9%). Full enteral feeds were achieved by median (IQR) of 6 (5,7) postnatal days. CONCLUSION: In preterm newborns (24-30 weeks) MBD incidence was 20.9% after BNS was implemented. Intravenous potassium salt of phosphorus and early use of HMF were safe and feasible.

Early calcium and phosphorus supplementation in VLBW infants to reduce metabolic bone disease of prematurity: a quality improvement initiative.

OBJECTIVE: To reduce the incidence of metabolic bone disease (MBD) among very low birthweight (VLBW) infants admitted to neonatal intensive care unit from baseline of 35% by 50% over 2 years by implementing a quality improvement (QI) initiative. METHODS: A multidisciplinary QI team used evidence-based interventions and the healthcare improvement model to reduce MBD rate in VLBW infants. The specific interventions included routine enteral supplementation of calcium and phosphorus using Human Milk Fortifier (HMF) to expressed breast milk by day 14 of life (Plan/Do/Study/Act (PDSA) cycle 1), parenteral and early enteral supplementation of calcium and phosphorus (PDSA cycles 2 and 3). We included VLBW infants admitted within the study period at birth and excluded babies with congenital malformations, skeletal disorders and those who died before 2 weeks of age. Compliance with adding HMF by day 14, compliance with adding calcium and phosphorus in total parenteral nutrition (TPN) from day 1 of life and compliance with starting HMF when the baby reached 100 mL/kg/day of feeds were used as process indicators. The incidence of MBD was used as an outcome indicator during the study. The incidence of MBD was tracked using the Statistical Process Control methodology. RESULTS: The baseline MBD rate in 2015 was 35%. After the first PDSA cycle, 20% developed MBD (p=0.02). The same was sustained for a period of 1 year with the rate of 22%. After the second and third PDSA cycles, there was a drop in the MBD rate to 17%, and sustained for 3 months with 21%. CONCLUSION: Implementation of QI initiatives decreased the MBD rate from 35% to <20%. Early parenteral calcium and phosphorus supplementation in TPN and optimising enteral supplementation with multicomponent fortifiers appear to have significant reduction in the incidence of MBD.

Dietary Bioactives: Their Role in the Prevention and Treatment of Cardiovascular and Metabolic Bone Diseases.

Cardiovascular and metabolic bone diseases are demanding health problems with high morbidity and mortality [...].

Absence of P2Y2 Receptor Does Not Prevent Bone Destruction in a Murine Model of Muscle Paralysis-Induced Bone Loss.

Increased incidence of bone fractures in the elderly is associated with gradual sarcopenia. Similar deterioration of bone quality is seen with prolonged bed rest, spinal cord injuries or in astronauts exposed to microgravity and, preceded by loss of muscle mass. Signaling mechanisms involving uridine-5'-triphosphate (UTP) regulate bone homeostasis via P2Y2 receptors on osteoblasts and osteoclasts, whilst dictating the bone cells' response to mechanical loading. We hypothesized that muscle paralysis-induced loss of bone quality would be prevented in P2Y2 receptor knockout (KO) mice. Female mice injected with botulinum toxin (BTX) in the hind limb developed muscle paralysis and femoral DXA analysis showed reduction in bone mineral density (<10%), bone mineral content (<16%) and bone area (<6%) in wildtype (WT) compared to KO littermates (with <13%, <21%, <9% respectively). The femoral metaphyseal strength was reduced equally in both WT and KO (<37%) and <11% in diaphysis region of KO, compared to the saline injected controls. Tibial micro-CT showed reduced cortical thickness (12% in WT vs. 9% in KO), trabecular bone volume (38% in both WT and KO), trabecular thickness (22% in WT vs. 27% in KO) and increased SMI (26% in WT vs. 19% in KO) after BTX. Tibial histomorphometry showed reduced formation in KO (16%) but unchanged resorption in both WT and KO. Furthermore, analyses of DXA and bone strength after regaining the muscle function showed partial bone recovery in the KO but no difference in the bone recovery in WT mice. Primary osteoblasts from KO mice displayed increased viability and alkaline phosphatase activity but, impaired bone nodule formation. Significantly more TRAP-positive osteoclasts were generated from KO mice but displayed reduced resorptive function. Our data showed that hind limb paralysis with a single dose of BTX caused profound bone loss after 3 weeks, and an incomplete reversal of bone loss by week 19. Our findings indicate no role of the P2Y2 receptor in the bone loss after a period of skeletal unloading in mice or, in the bone recovery after restoration of muscle function.

A probiotic mix partially protects against castration-induced bone loss in male mice.

Studies in postmenopausal women and ovariectomized mice show that the probiotic mix Lacticaseibacillus paracasei DSM13434, Lactiplantibacillus plantarum DSM 15312 and DSM 15313 (L. Mix) can protect from bone loss caused by sex steroid deficiency. Whether probiotic bacteria can protect bone also in sex steroid-deficient males is less studied. We used the orchiectomized mouse as a model for age-dependent bone loss caused by decreasing sex hormone levels in males. We treated 10-week-old male mice with either vehicle (veh) or L. Mix for 6 weeks, starting 2 weeks before orchiectomy (orx) or sham surgery. Importantly, mice treated with L. Mix had a general increase in total body bone mineral density (BMD) and lean mass (P ≤ 0.05) compared with veh-treated mice. Detailed computer tomography analysis of dissected bones showed increased trabecular BMD of the distal metaphyseal region of the femur in L. Mix compared to veh-treated orx mice (+8.0%, P ≤ 0.05). In the vertebra, L. Mix treatment increased trabecular bone volume fraction BV/TV (+11.5%, P ≤ 0.05) compared to veh in orx mice. Also, L. Mix increased the levels of short-chain fatty acids (SCFAs) such as propionate and acetate and important intermediates in SCFA synthesis such as succinate and lactate in the cecal content of male mice. In conclusion, L. Mix treatment resulted in a general increase in BMD in adult male mice and prevented trabecular bone loss in femur and vertebra of orx mice. These bone protective effects of L. Mix were associated with increased levels of SCFAs in the cecal content of male mice.

Wheel-Running Exercise Protects Ovariectomized Mice from Bone Loss via IFN-γ-Mediated Suppression of the NF-κB and MAPK Pathways.

Physical exercise is recommended as a preventative approach for osteoporosis; however, the effect of physical exercise on bone mass remains controversial. Additionally, the immune regulation of physical exercise on bone mass remains unclear. To determine whether wheel-running (WR) exercise contributes to improving bone mineral density (BMD) and investigate the involved immune mechanism, ovariectomized (OVX) and sham-operated mice were treated with 8 weeks of WR exercise. The distal femurs of the mice were sequentially scanned, reconstructed, and analyzed using microcomputed tomography and related software to assess BMD and bone microarchitecture. Flow cytometry assays were applied to investigate alterations in immune cells and inflammatory cytokines. In vitro, osteoclast differentiation was conducted to determine the effect of IFN-γ on osteoclastogenesis and the underlying mechanism. As a result, trabecular parameters were decreased in the OVX mice compared with the sham group. However, WR exercise significantly improved the deterioration in the bone microarchitecture of the OVX mice with an increase of 60.00% in BMD, 55.18% in bone volume, 66.67% in trabecular number, 32.52% in trabecular thickness, and a decrease of 19.44% in trabecular separation. Similarly, WR exercise increased the proportion of CD8+ T cells from 7.26 ± 1.71% to 10.23 ± 1.35% in the spleen and from 1.62 ± 0.54% to 2.38 ± 0.43% in the bone marrow of the OVX mice (P < 0.05). The expression of IFN-γ was also increased in the OVX + WR mice compared with the OVX mice (1.65 ± 0.45% vs. 2.26 ± 0.34%, P < 0.05). In vitro studies demonstrated an inhibitory effect of IFN-γ on osteoclastogenesis in a dose- and time-dependent manner. Meanwhile, the classical NF-κB and MAPK pathways were found to be critical in IFN-γ-mediated inhibition of osteoclast differentiation. In conclusion, our study discovered that WR exercise rescued bone loss in the OVX mice in an IFN-γ-mediated immunomodulatory manner. After WR exercise, IFN-γ expression was restored by activated CD8+ T cells, consequently leading to the inhibition of osteoclastogenesis and the recovery from bone loss through the NF-κB and MAPK pathways.

Simplification from tenofovir disoproxil fumarate plus lamivudine or emtricitabine plus ritonavir-boosted protease inhibitor to ritonavir-boosted atazanavir plus lamivudine in virologically suppressed HIV-infected adults with osteopenia: a pilot study.

BACKGROUND: Tenofovir disoproxil fumarate, particularly when given with a ritonavir-boosted PI, reduces bone mineral density (BMD) and increases bone turnover markers (BTMs). Ritonavir-boosted atazanavir plus lamivudine is a feasible simplified option. We evaluated whether switching from a triple ritonavir-boosted PI plus tenofovir disoproxil fumarate to a two-drug regimen of lamivudine plus ritonavir-boosted atazanavir would improve BMD. METHODS: Single-arm pilot study. Virologically suppressed patients on tenofovir disoproxil fumarate plus lamivudine or emtricitabine plus ritonavir-boosted PI with low BMD, without previous resistance mutations and/or virological failure to study drugs were switched to 100/300 mg of ritonavir-boosted atazanavir plus 300 mg of lamivudine once daily. The primary endpoint was BMD change by DXA at Week 48. RESULTS: There were 31 patients, 4 (13%) female, and median age was 40 years. Seven participants (22.5%) had osteoporosis. At 48 weeks, mean (SD) changes in spine and hip BMD were +0.01 (0.03) (P = 0.0239) and +0.013 (0.03) g/cm2 (P = 0.0046), respectively. Mean (SD) T-score changes were +0.1 (0.23) (P = 0.0089) and +0.25 (0.76) (P = 0.0197), respectively. N-telopeptide and urine tenofovir disoproxil fumarate toxicity markers showed significant improvements. One participant withdrew from the study and two were lost to follow-up. There were no virological failures, or serious or grade 3-4 adverse events. CONCLUSIONS: Switching from a tenofovir disoproxil fumarate plus ritonavir-boosted PI triple therapy to a lamivudine plus ritonavir-boosted atazanavir two-drug regimen in virologically suppressed HIV-infected adults with low BMD was safe, increased low BMD and reduced plasma markers of bone turnover and urine markers of tenofovir disoproxil fumarate toxicity over 48 weeks.

Anti-sclerostin antibodies and abaloparatide have additive effects when used as a countermeasure against disuse osteopenia in female rats.

Prolonged disuse and substantial mechanical unloading are particularly damaging to skeletal integrity. Preclinical studies in rodents and clinical studies have highlighted the need for potent bone anabolic drugs to counteract disuse-induced osteopenia. The aim of present study was to compare the efficacy of romosozumab (Scl-Ab) and abaloparatide (ABL), alone or in combination, to prevent botulinum toxin (BTX) induced bone loss in a rat model. Eighty female Wistar rats were divided into the following six groups: 1. Baseline (n = 12); 2. Control (Ctrl) (n = 12); 3. BTX (n = 12); 4. BTX + Scl-Ab (n = 16); 5. BTX + ABL (n = 12); and 6. BTX + Scl-Ab + ABL (n = 16). Disuse was achieved by injecting 4 IU BTX into the hind limb musculature at study start. Scl-Ab (25 mg/kg) was injected s.c. twice weekly, while ABL (80 µg/kg) was injected s.c. five days a week for four weeks. Hind limb disuse dramatically decreased muscle mass and skeletal integrity and deteriorated the cortical morphology and trabecular microstructure. Treatment with Scl-Ab alone prevented most of the adverse cortical and trabecular effects of disuse, while ABL monotherapy mainly attenuated the disuse-induced loss of femoral areal bone mineral density (aBMD). Moreover, the combination of Scl-Ab and ABL not only counteracted most of the negative skeletal effects of unloading, but also increased aBMD (+10% and +20%), epiphyseal trabecular bone volume fraction (BV/TV) (+25% and +73%), and metaphyseal bone strength (+18% and +30%) significantly above that of Scl-Ab or ABL monotherapy, respectively. The potent and additive osteoanabolic effect of Scl-Ab and ABL, when given in combination, is highly intriguing and underlines that an osteoanabolic bone gain can be maximized by utilizing two pharmaceuticals targeting different cellular signaling pathways. From a clinical perspective, a combination treatment may be warranted in patients where the osteoanabolic effect of either monotherapy is not sufficient, or if a dose-reduction is required due to adverse effects.