Homocysteine enhances bone resorption by stimulation of osteoclast formation and activity through increased intracellular ROS generation

Association Between Homocysteine and All-Cause Mortality Among Osteoarthritis Patients: A Cohort Study from the NHANES Database

This study explored the association between serum Hcy level and the all-cause mortality among osteoarthritis (OA) patients. This cohort study included patients diagnosed as OA from the National Health and Nutrition Examination Survey (NHANES) 1999-2006. Abbott Homocysteine assay, a fully automated fluorescence polarization immunoassay (FPIA) method, was used to measure the level of serum Hcy. Covariates included sociodemographic information, lifestyles, history of diseases and medications were extracted from the database. The weighted univariate, multivariate Cox proportional hazard models and restricted cubic splines (RCS) were utilized to explore the association between Hcy level and all-cause mortality in OA patients, with hazard ratios (HRs) and 95% confidence intervals (CIs). Subgroup analyses based on different age, gender, duration of OA, complications and C-reactive protein (CRP) were further assessed by this association. Totally 1384 OA patients were included in this study, of which 817 (59.03%) died by 31 December 2019. After adjusting all covariates, high Hcy level was associated with the high all-cause mortality among OA patients (HR=1.31, 95%CI: 1.02-1.67), especially in females (HR=1.43, 95%CI: 1.07-1.91), aged >60 years (HR=1.49, 95%CI: 1.14-1.94), duration of OA >10 years (HR=1.40, 95%CI: 1.01-1.95), with the history of hypertension (HR=1.37, 95%CI: 1.03-1.80), without the history of diabetes (HR=1.36, 95%CI: 1.01-1.82) or CRP >0.29 mg/l (HR=1.51, 95%CI: 1.04-2.19). High serum Hcy level was associated with high risk of all-cause mortality in OA patients. Our results suggest that serum Hcy is a promising biomarker for the prognosis of OA patients.

Decoding ferroptosis: transforming orthopedic disease management

As a mechanism of cell death, ferroptosis has gained popularity since 2012. The process is distinguished by iron toxicity and phospholipid accumulation, in contrast to autophagy, apoptosis, and other cell death mechanisms. It is implicated in the advancement of multiple diseases across the body. Researchers currently know that osteosarcoma, osteoporosis, and other orthopedic disorders are caused by NRF2, GPX4, and other ferroptosis star proteins. The effective relief of osteoarthritis symptoms from deterioration has been confirmed by clinical treatment with multiple ferroptosis inhibitors. At the same time, it should be reminded that the mechanisms involved in ferroptosis that regulate orthopedic diseases are not currently understood. In this manuscript, we present the discovery process of ferroptosis, the mechanisms involved in ferroptosis, and the role of ferroptosis in a variety of orthopedic diseases. We expect that this manuscript can provide a new perspective on clinical diagnosis and treatment of related diseases.

Exploring the effects of homocysteine metabolism in osteoporosis management in Indian adult females

Objectives: Women are at a significantly higher risk of osteoporotic fractures, largely due to progressive bone demineralization and impaired bone microarchitecture. Low bone mineral density (BMD) is a common condition in women worldwide. Disrupted homocysteine (Hcy) metabolism has been linked to reduced BMD and increased risk of osteoporotic fractures. Hyperhomocysteinemia (Hhcy) affects osteoblast and osteoclast activity, interferes with collagen cross-linking in the extracellular matrix, and has a detrimental effect on bone health. This study aimed to establish the association between hematological and biochemical parameters and osteoporosis in adult females. Methods: We measured Hcy, creatinine, uric acid (UA), vitamin B12, and vitamin D levels. Significantly elevated Hcy (27.322 ± 0.816 vs 10.152 ± 0.381 µmol/L), creatinine (0.670 ± 0.012 vs 0.587 ± 0.011 mg/dL), and UA (5.118 ± 0.083 vs 2.786 ± 0.060 mg/dL) were found in osteoporotic females, while reduced concentrations of vitamin B12 (148.883 ± 2.192 vs 294.14 ± 6.505 pg/mL) and vitamin D (24.98 ± 0.621 vs 33.7 ± 0.652 ng/mL) were observed. Results: Hematological parameters were found differentially expressed in osteoporotic females. Elevated Hcy levels, combined with reduced vitamin B12 and vitamin D, were strongly associated with decreased BMD and a higher susceptibility to osteoporotic fractures. Women with increased Hcy levels also had lower T-scores compared to those without Hhcy. Conclusions: These findings suggest that Hcy plays a critical role in bone resorption and osteoporotic fractures. Regulating Hcy metabolism may serve as an effective therapeutic strategy for managing bone resorption and osteoporosis. We hypothesize that elevated Hcy levels are closely related to low BMD and an increased risk of osteoporosis.

Association between folate intake and radiographic progression, pain function scores in subjects with radiographic knee osteoarthritis: Data from the osteoarthritis initiative

BACKGROUND

Folate has an important role in the functioning of the musculoskeletal system, including modulation of inflammation, immunity, cartilage regeneration, prevention of osteoporosis, and maintenance of muscle strength, but evidence on the association between folate intake and knee pain, functional scores, and radiographic progression in patients with knee osteoarthritis (OA) is still limited.

METHODOLOGY

Our population-based cohort was extracted from the osteoarthritis initiative (OAI), focusing on individuals with prevalent radiographic knee OA (with a Kellgren-Lawrence score ≥2). Folate consumption was determined using the food frequency questionnaire. Data regarding the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and radiographic readings were collected over 48 months. We analyzed the compiled data using generalized additive mixed models.

RESULTS

Our cohort consisted of 1472 OA patients (626 men and 846 women, mean [SD] age 62.35 [8.92]). At the 48-month follow-up, we observed a significant correlation between higher folate intake and a slower progression of knee pain and functional scores, as evidenced by a statistically significant decrease in the WOMAC total score, WOMAC pain subscale score, and WOMAC function/disability subscale score (p < .05). The fully adjusted models estimated a reduction of -0.028 points per 50 μg/1000 kcal of daily folate intake on the WOMAC pain subscale, -0.117 points on the WOMAC function subscale, and -0.160 points on the total WOMAC scale. Furthermore, our nonparametric fit analysis suggested that a higher intake of folate might decelerate the radiographic progression of OA. Stratified analyses indicated that an increase in folate consumption might particularly benefit men, older adults, overweight and obese individuals, and those with a higher dietary fiber intake.

CONCLUSION

Higher folate intake is correlated with improved knee function and reduced pain in patients with knee OA and might deter the radiographic progression of OA. The benefits appear to be more pronounced in men, older adults, overweight and obese individuals, and those with a higher dietary fiber intake.

Outcomes following spinal instrumented fusions in patients with parkinson's disease: a systematic review and meta-analysis

BACKGROUND

Parkinson's Disease (PD) patients represent challenging spinal surgery candidates due to associated frailty and deformity. This study consolidates the literature concerning spinal surgery outcomes in PD versus non-PD patients, to evaluate if PD predisposes patients to worse post-operative outcomes, so that treatment protocols can be optimised.

METHODS

A systematic review and meta-analysis was conducted of PubMed/Medline, Embase, and Google Scholar databases per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies of interest included comparative (PD versus non-PD) cohorts undergoing spinal instrumented fusions. Post-operative clinical outcomes were collated and compared for significance between cohorts. Further analysis was made on outcomes based on the different surgical procedures performed (Anterior Cervical Discectomy and Fusion (ACDF), Thoracolumbar or Lumbar fusions, Thoracolumbar or Lumbar fusions without Osteoporotic Vertebral Compression fracture (OVCF) patients). All statistical analysis was performed using The R Project for Statistical Computing (version 4.1.2), with a p-value of < 0.05 deemed statistically significant.

RESULTS

In total, 2,323,650 patients were included across 16 studies. Of those, 2,308,949 (99.37%) were patients without PD (non-PD), while 14,701 (0.63%) patients had PD at time of surgery. The collective mean age was 68.23 years (PD: 70.14 years vs non-PD: 64.86 years). Comparatively, there were 844,641 males (PD: 4,574; non-PD: 840,067) and 959,908 females (PD: 3,213; non-PD: 956,695). Overall, there were more post-operative complications in the PD cohort. Specifically, PD patients experienced significantly more surgical site infections (p = 0.01), increased rates of revision surgeries (p = 0.04) and increased venous thromboembolic events (p = 0.02) versus the non-PD cohort. In thoracolumbar/lumbar spinal fusions without OVCF patients, the PD cohort had increased rates of revision surgeries (p < 0.01) in comparison to the non-PD cohort. However, when including OVCF patients in thoracolumbar/lumbar spinal fusions, the PD cohort had significantly higher amounts of postoperative complications (p = 0.01), pneumonia (p = 0.02), and revision surgeries (p < 0.01) when compared to the non-PD cohort.

CONCLUSION

Although more robust prospective studies are needed, the results of this study highlight the need for advanced wound care management in the postoperative period, both in-hospital and in the community, in addition to comprehensive multidisciplinary care from allied health professionals, with potential for the use of Enhanced Recovery After Surgery (ERAS) protocols in PD patients undergoing spinal instrumented fusions.

Cedrol alleviates postmenopausal osteoporosis in rats through inhibiting the activation of the NF-κB signaling pathway

Pharmacological studies have shown that Cedrol (CE) exhibits extensive biological activities, including anti-inflammatory and analgesic. Moreover, it can inhibit the NF-κB pathway and the expression of various associated proteins. This study aimed to investigate the role of CE in postmenopausal osteoporosis. The results showed that intragastric administration of CE (10 and 20 mg/kg) significantly improved the bone microstructure damage and increased bone mineral density, trabecular bone volume, and bone trabecular thickness in ovariectomized (OVX) rats (p < 0.05). CE treatment additionally made a well-organized arrangement of bone trabeculae and improved its thickness and density. Compared with the OVX group, the levels of tartrate-resistant acid phosphatase from 5b and C-terminal telopeptide of type I collagen were significantly reduced by 42.75% and 49.27% in the OVX + CE rats (p < 0.05). TRAP staining visually showed that the number of osteoclasts in the femur tissue of CE-treated rats was less than that of the OVX group. The expressions of nuclear factor of activated T-cells, cytoplasmic 1, acid phosphatase 5, and cathepsin K in OVX + CE rats were significantly decreased by 51.61%, 46.07%, and 50.34% compared to the OVX group (p < 0.01). In addition, CE intervention effectively reduced the phosphorylation levels of P65 and IκBα and inhibited the NF-κB signaling pathway. Meanwhile, CE diminished the number of multinucleated osteoclasts induced by receptor activator for nuclear factor-κB ligand and hindered cell fusion as well as nuclear translocation of osteoclast precursor cells P65. In conclusion, CE inhibits osteoclastogenesis by suppressing the activation of the NF-κB signaling pathway, thereby alleviating postmenopausal osteoporosis.

The role of ferroptosis in intervertebral disc degeneration

Nucleus pulposus, annulus fibrosus, and cartilage endplate constitute an avascular intervertebral disc (IVD), which is crucial for spinal and intervertebral joint mobility. As one of the most widespread health issues worldwide, intervertebral disc degeneration (IVDD) is recognized as a key contributor to back and neck discomfort. A number of degenerative disorders have a strong correlation with ferroptosis, a recently identified novel regulated cell death (RCD) characterized by an iron-dependent mechanism and a buildup of lipid reactive oxygen species (ROS). There is growing interest in the part ferroptosis plays in IVDD pathophysiology. Inhibiting ferroptosis has been shown to control IVDD development. Several studies have demonstrated that in TBHP-induced oxidative stress models, changes in ferroptosis marker protein levels and increased lipid peroxidation lead to the degeneration of intervertebral disc cells, which subsequently aggravates IVDD. Similarly, IVDD is significantly relieved with the use of ferroptosis inhibitors. The purpose of this review was threefold: 1) to discuss the occurrence of ferroptosis in IVDD; 2) to understand the mechanism of ferroptosis and its role in IVDD pathophysiology; and 3) to investigate the feasibility and prospect of ferroptosis in IVDD treatment.

Genetically predicted circulating serum homocysteine levels on osteoporosis: a two-sample mendelian randomization study

To investigate the causal relationship between circulating serum homocysteine (Hcy) levels and osteoporosis (OP). Using public datasets gathered from independently published genome-wide association studies (GWAS), Mendelian randomization (MR) analysis was done to investigate the causal influence of Hcy on OP. SNPs were selected from a meta-analysis of GWAS on Hcy concentrations in 44,147 individuals of European ancestry. Meanwhile, SNPs of individuals of European descent for OP were extracted from the Genetic Factors of Osteoporosis Consortium (GEFOS) UK Biobank. The odds ratio (OR) of inverse variance weighted (IVW) approaches was established as the primary outcome. Moreover, weighted median (WM) and MR-Egger regressions were included in the sensitivity analysis. There were no causal effects of Hcy on forearm bone mineral density and lumbar bone mineral density according to IVW, MR-Egger, and WM analyses (all p > 0.05). In the IVW, we discovered the causality between genetically predicted Hcy and heel bone mineral density (H-BMD) with an OR of 0.96 [95% confidence interval (CI) = 0.927-0.990, p = 0.011]. In the additional sensitivity analysis, WM regression (OR = 0.97, 95% CI = 0.995-1.076, p = 0.084) and MR-Egger regression (OR = 0.98, 95% CI = 0.918-1.049, p = 0.609) yielded values that were comparable in direction but less precise. The MR-Egger intercept, funnel plot, and IVW all indicate the absence of any discernible directional pleiotropy. The leave-one-out analysis revealed that a single SNP did not influence the results of the MR analysis. In conclusion, our MR investigation revealed evidence of a causal relationship between circulating serum Hcy levels and H-BMD, but not OP in the European population. However, larger sample sizes are needed in the future to get more reliable conclusions.

Effect of Vitamin B6 on Osteoporosis Fracture

Osteoporosis is a medical condition that causes bones to become weak and brittle, making them more likely to break or fracture. This condition occurs when the body loses too much bone, makes too little bone, or both. Bones are living tissues that are constantly being broken down and rebuilt. However, as we age, this process slows down, and our bodies may be unable to replace bone as quickly as it is broken down. This can lead to a loss of bone density, making bones weaker and more prone to fracture. Unfortunately, osteoporosis often has no symptoms until a bone is broken, so taking steps to prevent this condition is essential. This may include getting enough calcium and vitamin D, engaging in weight-bearing exercise, quitting smoking, limiting alcohol intake, and taking medication if prescribed by a doctor. Vitamin B6, also known as pyridoxine, is a water-soluble vitamin that plays a vital role in various bodily functions. It is part of the B-vitamin complex and is essential for metabolizing proteins, carbohydrates, and fats. Vitamin B6 produces neurotransmitters such as serotonin, which helps regulate mood, and dopamine, which is involved in motivation and reward. Several previous studies have found that women with higher intakes of vitamin B6 have higher bone mineral density (BMD) of the hips and spine than women with lower intakes. Another study found that men and women with higher blood levels of vitamin B6 had higher BMD in the hips and spine.

Associations of Homocysteine, Folate, and Vitamin B12 with Osteoarthritis: A Mendelian Randomization Study

Homocysteine, inversely related to folate and vitamin B12, is an independent risk factor for several age-related disorders. However, little is known about the association of homocysteine and related vitamins with osteoarthritis (OA). This study aimed to elucidate the potential causal effects of homocysteine, folate, and vitamin B12 on site- and gender-specific OA by applying the two-sample Mendelian randomization (MR) approach. Genetically predicted homocysteine showed adverse effects on overall OA (95% confidence interval (CI): 1.044–1.155), knee OA (95% CI: 1.000–1.167), hip OA (95% CI: 1.057–1.297), and spine OA (95% CI: 1.017–1.216). Genetically predicted folate showed protective effects on overall OA (95% CI: 0.783–0.961) and spine OA (95% CI: 0.609–0.954). Folate (95% CI: 0.887–1.004) and vitamin B12 (95% CI: 0.886–1.009) showed a protective trend against knee OA. The patterns of associations were site and gender specific. In conclusion, homocysteine had adverse effects on OA, especially on OA at weight-bearing joints and in females. Folate and vitamin B12 had protective effects on OA. Homocysteine-lowering interventions may be a potential option in the treatment and prevention of OA.

AA. The effect of Hyperhomocysteinemia on the Osteoclasts activity in Male New Zealand White Rabbits

Methionine is a specific amino acid which contains sulfur, and can be used to make proteins, found in fish, meat, and dairy products, the excess intake of L-methionine lead to elevated homocysteine (Hcy) level that known as Hyperhomocysteinemia (HHcy). Increased Hcy plasma may represent an independent risk factor for osteoporotic fractures, and therefore may also negatively affect bone metabolism. This study was designed to examine the impact of Hcy on osteoclast activity in Male Rabbits, following methionine overload. To achieve this study's aims, we recruiting (20) males of New Zealand white rabbits that were divided into (10/group) control group and a group treated with methionine. Then after the intubation of methionine overload, we measured the "Receptor Activator of Nuclear factor Kappa-b" (RANK) and "Receptor Activator of Nuclear factor Kappa-b ligand" (RANK-L) levels in the blood, in addition to histological examination of the trabecular structure of femur bone. The results show a significant (p≤0.001) increase in serum RANK and RANK-L levels of methionine treated group in comparison with the control group. The histological examination of the trabecular structure of femur bone shows an increase in osteoclasts percentage, activity, and large resorption pits in the methionine treated group. The HHcy that was induced by methionine overload, caused an increase in osteoclast activity and numbers in male rabbits suggested a mechanistic role for bone resorption by Hcy. Future research clarifying the mechanistic function of elevated concentrations of Hcy in osteoporosis may have important therapeutic implications.

Inferring causal effects of homocysteine and B-vitamin concentrations on bone mineral density and fractures: Mendelian randomization analyses

Objectives

In the progress of bone metabolism, homocysteine (Hcy) and B vitamins play substantial roles. However, the causal associations of homocysteine, B-vitamin concentrations with bone mineral density (BMD), and fractures remain unclear. Therefore, we employed a two-sample Mendelian randomization (MR) design to infer the causal effects of Hcy and B vitamins on BMD and fractures.

Methods

We selected instrumental variables from large genome-wide association studies (GWASs). Specifically, the exposures mainly included Hcy (sample size: 44,147), vitamin B12 (sample size: 45,576), folate (sample size: 37,465), and vitamin B6 (sample size: 1,864). The outcome variables included total body BMD (sample size: 66,628), heel BMD (sample size: 142,487), femoral neck BMD (sample size: 32,735), lumbar spine BMD (sample size: 28,498), and forearm BMD (sample size: 8143). Additionally, the total body BMD in several age strata was also included. Furthermore, the fractures of the forearm, femoral neck, lumbar spine, heel corresponding with the BMD regions, and femoral neck and lumbar spine BMD in men and women, separately, were added as additional outcomes. Two-sample MR approaches were utilized in this study. Inverse variance weighting (IVW) was adopted as the main analysis. MR-PRESSO, MR-Egger, the weighted median estimate, and multivariable MR were performed as sensitivity methods.

Results

In the main analysis, Hcy concentrations have an inverse association with heel BMD (Beta = 0.046, 95% confidence interval (CI) -0.073 to -0.019, P = 9.59E-04) per SD unit. In addition, for one SD increase of vitamin B12, the total body BMD decreased 0.083 unit (95%CI -0.126 to -0.040, P = 1.65E-04). The trend was more obvious in age over 45 years (Beta = -0.135, 95%CI -0.203-0.067, P = 9.86E-05 for age 45-60; Beta = -0.074, 95%CI -0.141 to -0.007, P = 0.031 for age over 60 years). No association of B vitamins and Hcy levels with the risk of fractures and femoral neck and lumbar spine BMD in men and women was found in this study. Other sensitivity MR methods elucidated consistent results.

Conclusions

Our findings indicated that there exist the inversely causal effects of Hcy and vitamin B12 on BMD in certain body sites and age strata. These give novel clues for intervening bone-related diseases in public health and nutrition.

Changes in interstitial fluid flow, mass transport and the bone cell response in microgravity and normogravity

In recent years, our scientific interest in spaceflight has grown exponentially and resulted in a thriving area of research, with hundreds of astronauts spending months of their time in space. A recent shift toward pursuing territories farther afield, aiming at near-Earth asteroids, the Moon, and Mars combined with the anticipated availability of commercial flights to space in the near future, warrants continued understanding of the human physiological processes and response mechanisms when in this extreme environment. Acute skeletal loss, more severe than any bone loss seen on Earth, has significant implications for deep space exploration, and it remains elusive as to why there is such a magnitude of difference between bone loss on Earth and loss in microgravity. The removal of gravity eliminates a critical primary mechano-stimulus, and when combined with exposure to both galactic and solar cosmic radiation, healthy human tissue function can be negatively affected. An additional effect found in microgravity, and one with limited insight, involves changes in dynamic fluid flow. Fluids provide the most fundamental way to transport chemical and biochemical elements within our bodies and apply an essential mechano-stimulus to cells. Furthermore, the cell cytoplasm is not a simple liquid, and fluid transport phenomena together with viscoelastic deformation of the cytoskeleton play key roles in cell function. In microgravity, flow behavior changes drastically, and the impact on cells within the porous system of bone and the influence of an expanding level of adiposity are not well understood. This review explores the role of interstitial fluid motion and solute transport in porous bone under two different conditions: normogravity and microgravity.

Trimethylamine-N-Oxide Promotes Osteoclast Differentiation and Bone Loss via Activating ROS-Dependent NF-κB Signaling Pathway

Trimethylamine-N-oxide (TMAO), an important gut microbiota (GM)-derived metabolite, has been shown to be abnormally increased in osteoporosis. However, the role and underlying mechanism of TMAO in regulating bone loss during osteoporosis have not been fully investigated. In the current study, we found that 100–400 μM TMAO dose-dependently enhanced TRAP-positive osteoclasts, F-actin ring formation, and resorption area on bovine bone slices and up-regulated osteoclast-related gene expression (Calcr, Traf6, Dcstamp, Acp5, C-Fos, and NFATc1). Western blotting validated that TMAO not only activated NF-κB signaling pathway but also stimulated c-Fos and NFATc1 protein expression in a dose-dependent manner. Furthermore, BAY 11-7082, an NF-κB inhibitor, pretreatment markedly suppressed TRAP-positive osteoclast formation and osteoclast-related genes under TMAO treatment. BAY 11-7082 also inhibited p-p65/p65, c-Fos, and NFATc1 protein expression promoted by TMAO. Moreover, TMAO significantly increased ROS production, which was inhibited by N-acetylcysteine (NAC), an ROS antagonist. In addition, we proved that NAC pretreatment could inhibit TMAO-promoted NF-κB activation. NAC also suppressed TRAP-positive osteoclast formation, osteoclast-related gene expression, and protein expression of c-Fos and NFATc1 under TMAO treatment. In vivo studies showed significantly decreased bone mass and increased TRAP-positive osteoclasts in TMAO-treated C57BL/6 mice. Moreover, western-blotting and immunohistochemical staining showed that TMAO administration markedly stimulated NF-κB p65 expression. Additionally, TMAO administration significantly promoted the gene and protein expression of C-Fos and NFATc1. In conclusion, TMAO could promote osteoclast differentiation and induce bone loss in mice by activating the ROS-dependent NF-κB signaling pathway.

Paradoxical role of reactive oxygen species in bone remodelling: implications in osteoporosis and possible nanotherapeutic interventions

Osteoporosis is a metabolic bone disorder that affects both sexes and is the most common cause of fractures. Osteoporosis therapies primarily inhibit osteoclast activity, and are seldom designed to trigger new bone growth thereby frequently causing severe systemic adverse effects. Physiologically, the intracellular redox state depends on the ratio of pro-oxidants, oxidizing agents (reactive oxygen species, ROS) and antioxidants. ROS is the key contributor to oxidative stress in osteoporosis as changes in redox state are responsible for dynamic bone remodeling and bone regeneration. Imbalances in ROS generation vs. antioxidant systems play a pivotal role in pathogenesis of osteoporosis, stimulating osteoblasts and osteocytes towards osteoclastogenesis. ROS prevents mineralization and osteogenesis, causing increased turnover of bone loss. Alternatively, antioxidants either directly or indirectly, contribute to activation of osteoblasts leading to differentiation and mineralization, thereby reducing osteoclastogenesis. Owing to the unpredictability of immune responsiveness and reported adverse effects, despite promising outcomes from drugs against oxidative stress, treatment in clinics targeting osteoclast has been limited. Nanotechnology-mediated interventions have gained remarkable superiority over other treatment modalities in regenerative medicine. Nanotherapeutic approaches exploit the antioxidant properties of nanoparticles for targeted drug delivery to trigger bone repair, by enhancing their osteogenic and anti-osteoclastogenic potentials to influence the biocompatibility, mechanical properties and osteoinductivity. Therefore, exploiting nanotherapeutics for maintaining the differentiation and proliferation of osteoblasts and osteoclasts is quintessential.

Homocysteine Levels and Osteoporotic Fracture in a Population Aged 55 Years Over in Medan District Indonesia

BACKGROUND: Osteoporosis is a chronic, progressive, systemic, skeletal, multifactorial disorder characterized by low bone mass, microarchitectural deterioration of bone tissues that increased the risk of fragility fracture. The increased prevalence of early osteoporosis in homocystinuria illustrates that homocysteine metabolism is involved in the process of osteoporosis. AIM: This study was aimed to look for the relationship between homocysteine levels in the blood and the occurrence of osteoporotic fractures in the population above 55 years old. METHODS: This is a descriptive study with cross-sectional approach, total sixty-five patients aged 55 years or older with osteoporotic fracture and as a control group without osteoporotic fracture. Blood pressure, heart rate, and body weight were recorded, bone density was measured using central dual-energy x-ray absorptiometry (DXA) machine/DXA and homocysteine plasma levels were measured using the enzyme-linked immunoassay method. RESULTS: Total of 65 samples with age range between 55 and 88 years, they were 38 peoples with osteoporosis, which 12 got the osteoporotic fracture. Among the 16 samples in osteopenia group, two got the fracture, among 11 samples with normal bone density, one got the osteoporotic fracture. There was statistical significant between fracture and bone mineral density (p = 0.00) and no statistical significant between bone density and gender (p = 0.08), bone density and body mass index (BMI) (p = 0.11). There was statistical significant correlation between homocysteine and age (p = 0.02), age and bone density (p = 0.002) but no statistical significant correlation between homocysteine and BMI (p = 0.07), homocysteine and osteoporotic fracture (p = 0.87). CONCLUSIONS: Homocysteine level did not increased the incidence of osteoporotic fracture, however homocysteine increased with aging and correlated with bone mineral density.

Osteoporosis Complications in Crohn's Disease Patients: Factors, Pathogenesis, and Treatment Outlines

The causes of osteoporosis in Crohn’s disease (CD) are multifactorial; cytokines, steroids, and vitamin deficiency all have an essential role. It is imperative to distinguish the factors that contribute to bone resorption, potentially increasing the risk of low bone mineral density (BMD), osteoporosis, and fracture. However, the pathogenicity of osteoporosis associated with CD remains unclear. Although osteoporosis treatment may vary between bisphosphonate and corticosteroid, infliximab's efficacy, when combined with immune modulators, suppresses both CD symptoms and osteoporosis progression. In this review, we aim to understand the present pathogenicity of osteoporosis, including the factors pro-inflammatory cytokines, chronic steroid use, and malnutrition, developing osteoporosis in a different pathological way, and to assist the treatment lines implying a positive outcome of osteoporosis in CD patients.

Osteoporosis is considered to be one of the early complications of CD where early detection can prevent osteoporosis progression. This can be done by utilizing dual-energy X-ray-absorptiometry (DEXA) to evaluate the Z-score and treat the existing factors that have a role in the progression of osteoporosis in CD patients.

Adequate intake and supplementation of B vitamins, in particular folic acid, can play a protective role in bone health

In vitro and animal model studies have shown that B vitamins (VB) deficiency have negative consequences on bone, as a result of direct or mediated activity of hyperhomocysteinemia. However, there are still no precise indications regarding a possible VB role in order to maintain bone health. So, the aim of this narrative review was to consider the state of the art on correlation between VB dietary intake, blood levels and supplementation and bone health (bone mineral density (BMD), bone turnover markers and fractures risk) in humans. This review included 29 eligible studies. Considering VB blood levels, the 14 studies considered have shown that low serum folate can be a factor risk for reduced BMD and fractures in elderly, particularly women; no independent association was found for other VB. Studies that evaluate relationship between VB dietary intake and BMD are only 2; one, conducted on 1869 women, demonstrated a positive effect of folate intake on BMD, another demonstrated a dose-dependent inverse relationship between vitamin B6 dietary intake and risk of hip fracture, but only for 35298 female participants. Regarding the relationship between BV supplementation and bone health (9 studies with only VB and 4 with other nutrients), all studies that considered patients with hyperhomocysteinemia or with low folate blood levels, are in agreement in demonstrating that folate supplementation (500mcg-5mg) is useful in improving BMD. In conclusion, a request for folate and homocysteine blood levels in elderly patients with osteopenia/osteoporosis is mandatory. For patients with hyperhomocysteinemia or with low folate blood levels, folate supplementation (500mcg-5mg) is crucial.

Inhibitory Effects of Rhaponticin on Osteoclast Formation and Resorption by Targeting RANKL-Induced NFATc1 and ROS Activity

The extravagant osteoclast formation and resorption is the main cause of osteoporosis. Inhibiting the hyperactive osteoclastic resorption is considered as an efficient treatment for osteoporosis. Rhaponticin (RH) is a small molecule that has been reported to possess anti-inflammatory, anti-allergic, anti-fibrotic, and anti-diabetic activities. However, the influence of RH on osteoclasts differentiation and function is still unclear. To this end, an array of assays including receptor activator of nuclear factor kappa-Β (NF-κB) ligand (RANKL) induced osteoclastogenesis, tartrate-resistant acidic phosphatase (TRAcP) staining, immunofluorescence, and hydroxyapatite resorption were performed in this study. It was found that RH had significant anti-catabolic effects by inhibiting osteoclastogenesis and bone resorption without cytotoxicity. Mechanistically, the expression of NADPH oxidase 1 (Nox1) was found to be suppressed and antioxidant enzymes including catalase, superoxide dismutase 2 (SOD-2), and heme oxygenase-1(HO-1) were enhanced following RH treatment, suggesting RH exhibited antioxidant activity by reducing the generation of reactive oxygen species (ROS) as well as enhancing the depletion of ROS. In addition, MAPKs, NF-κB, and intracellular Ca2+ oscillation pathways were significantly inhibited by RH. These changes led to the deactivation of osteoclast master transcriptional factor-nuclear factor of activated T cells 1 (NFATc1), as examined by qPCR and Western blot assay, which led to the decreased expression of downstream integrin β3, c-Fos, cathepsin K, and Atp6v0d2. These results suggested that RH could effectively suppress RANKL-regulated osteoclast formation and bone resorption. Therefore, we propose that RH can represent a novel natural small molecule for the treatment of osteoporosis by inhibiting excessive osteoclast activity.

Oral manifestations associated with inherited hyperhomocysteinemia: A first case description

Hyperhomocysteinemia is a rare disease caused by nutritional deficiencies or genetic impairment of cysteine metabolism. To date, no oral manifestations of hyperhomocysteinemia have been described in humans. Therefore, to our knowledge, the present case report is the first description of a hyperhomocysteinemic patient showing oral tissue alterations leading to both early tooth loss and failed implant osseointegration. The patient presented with a methylenetetrahydrofolate reductase gene mutation (677T polymorphism) leading to mild hyperhomocysteinemia. The radiologic analysis showed hyperdense lesions scattered in the maxillae. The histologic observations indicated alterations in both collagen and elastic networks in the gingiva and dermis. Interestingly, the presence of ectopic mineralized inclusions was noted in both periodontal ligament and gingiva. Strong osteoclastic activity was associated with abnormal calcification of trabecular spaces. Uneven oral tissue remodeling due to high tissue levels of homocysteine could explain the pathologic manifestations observed in this case.

Melatonin effects on bone: Implications for use as a therapy for managing bone loss

Melatonin is the primary circadian output signal from the brain and is mainly synthesized in pinealocytes. The rhythm and secretion of melatonin are under the control of an endogenous oscillator located in the SCN or the master biological clock. Disruptions in circadian rhythms by shift work, aging, or light at night are associated with bone loss and increased fracture risk. Restoration of nocturnal melatonin peaks to normal levels or therapeutic levels through timed melatonin supplementation has been demonstrated to provide bone-protective actions in various models. Melatonin is a unique molecule with diverse molecular actions targeting melatonin receptors located on the plasma membrane or mitochondria or acting independently of receptors through its actions as an antioxidant or free radical scavenger to stimulate osteoblastogenesis, inhibit osteoclastogenesis, and improve bone density. Its additional actions on entraining circadian rhythms and improving quality of life in an aging population coupled with its safety profile make it an ideal therapeutic candidate for protecting against bone loss in susceptible populations. The intent of this review is to provide a focused discussion on bone loss and disorders of the bone as it relates to melatonin and conditions that modify melatonin levels with the hope that future therapies include those that include melatonin and correct those factors that modify melatonin levels like circadian disruption.

Evaluation of the relationship between homocysteine levels and bone mineral density in postmenopausal women

OBJECTIVE

The current study aimed to evaluate the relationship between homocysteine (Hcy) levels and bone mineral density (BMD) in postmenopausal women.

METHODS

The present, cross-sectional study included 760 postmenopausal women. The following variables were recorded: age, age at menopause, body mass index (BMI), BMD (measured by dual-energy X-ray absorptiometry [DXA] scanning and expressed as lumbar, femoral neck and total hip T-scores), smoking status, biochemical parameters (Hcy, creatinine, calcium, phosphorus, vitamin D and parathormone levels) and vitamin D supplementation.

RESULTS

The mean age of the sample population was 56.4 ± 5.77 years and the mean age at menopause was 49.9 ± 3.62 years. The mean BMI was 25.2 ± 4.49 kg/m². In the current study, a comparison of the subjects with osteoporosis, osteopenia and normal BMD revealed that the subjects in the low BMD group were significantly older (p < 0.001), had a lower age at menopause (p < 0.001) and had lower BMI (p < 0.001). There was no statistically significant difference among the groups with regard to the plasma levels of Hcy (p = 0.946). The levels of Hcy were positively correlated to the creatinine levels (r = 0.21). The present study did not observe any significant correlations between the Hcy levels and other parameters.

CONCLUSIONS

In the present study, 15.3% of the subjects had hyperhomocysteinemia and 62.11% had low BMD. The current results obtained from a group of postmenopausal women suggest that the plasma levels of Hcy are not related to BMD in the lumbar spine (L1-L4), femoral neck and total hip. In the current study, age, age at menopause and low BMI were observed to be associated with low BMD.

Probiotic Supplementation Facilitates Recovery of 6-OHDA-Induced Motor Deficit via Improving Mitochondrial Function and Energy Metabolism

Parkinson’s disease (PD) is a neurodegenerative disease associated with progressive impairment of motor and non-motor functions in aging people. Overwhelming evidence indicate that mitochondrial dysfunction is a central factor in PD pathophysiology, which impairs energy metabolism. While, several other studies have shown probiotic supplementations to improve host energy metabolism, alleviate the disease progression, prevent gut microbiota dysbiosis and alter commensal bacterial metabolites. But, whether probiotic and/or prebiotic supplementation can affect energy metabolism and cause the impediment of PD progression remains poorly characterized. Therefore, we investigated 8-weeks supplementation effects of probiotic [Lactobacillus salivarius subsp. salicinius AP-32 (AP-32)], residual medium (RM) obtained from the AP-32 culture medium, and combination of AP-32 and RM (A-RM) on unilateral 6-hydroxydopamine (6-OHDA)-induced PD rats. We found that AP-32, RM and A-RM supplementation induced neuroprotective effects on dopaminergic neurons along with improved motor functions in PD rats. These effects were accompanied by significant increases in mitochondrial activities in the brain and muscle, antioxidative enzymes level in serum, and altered SCFAs profile in fecal samples. Importantly, the AP-32 supplement restored muscle mass along with improved motor function in PD rats, and produced the best results among the supplements. Our results demonstrate that probiotic AP-32 and A-RM supplementations can recover energy metabolism via increasing SCFAs producing and mitochondria function. This restoring of mitochondrial function in the brain and muscles with improved energy metabolism might additionally be potentiated by ROS suppression by the elevated generation of antioxidants, and which finally leads to facilitated recovery of 6-OHDA-induced motor deficit. Taken together, this work demonstrates that probiotic AP-32 supplementation could be a potential candidate for alternate treatment strategy to avert PD progression.

Natural medicine delivery from biomedical devices to treat bone disorders: A review

With an increasing life expectancy and aging population, orthopedic defects and bone graft surgeries are increasing in global prevalence. Research to date has advanced the understanding of bone biology and defect repair mechanism, leading to a marked success in the development of synthetic bone substitutes. Yet, the quest for functionalized bone grafts prompted the researchers to find a viable alternative that regulates cellular activity and supports bone regeneration and healing process without causing serious side-effects. Recently, researchers have introduced natural medicinal compounds (NMCs) in bone scaffold that enables them to release at a desirable rate, maintains a sustained release allowing sufficient time for tissue in-growth, and guides bone regeneration process with minimized risk of tissue toxicity. According to World Health Organization (WHO), NMCs are gaining popularity in western countries for the last two decades and are being used by 80% of the population worldwide. Compared to synthetic drugs, NMCs have a broader range of safety window and thus suitable for prolonged localized delivery for bone regeneration. There is limited literature focusing on the integration of bone grafts and natural medicines that provides detailed scientific evidences on NMCs, their toxic limits and particular application in bone tissue engineering, which could guide the researchers to develop functionalized implants for various bone disorders. This review will discuss the emerging trend of NMC delivery from bone grafts, including 3D-printed structures and surface-modified implants, highlighting the significance and potential of NMCs for bone health, guiding future paths toward the development of an ideal bone tissue engineering scaffold. STATEMENT OF SIGNIFICANCE: To date, additive manufacturing technology provids us with many advanced patient specific or defect specific bone constructs exhibiting three-dimensional, well-defined microstructure with interconnected porous networks for defect-repair applications. However, an ideal scaffold should also be able to supply biological signals that actively guide tissue regeneration while simultaneously preventing post-implantation complications. Natural biomolecules are gaining popularity in tissue engineering since they possess a safer, effective approach compared to synthetic drugs. The integration of bone scaffolds and natural biomolecules exploits the advantages of customized, multi-functional bone implants to provide localized delivery of biochemical signals in a controlled manner. This review presents an overview of bone scaffolds as delivery systems for natural biomolecules, which may provide prominent advancement in bone development and improve defect-healing caused by various musculoskeletal disorders.

Causal effects of homocysteine levels on the changes of bone mineral density and risk for bone fracture: A two-sample mendelian randomization study

BACKGROUND & AIMS

Observational studies have demonstrated the relations of homocysteine (HCY) with bone mineral density (BMD) and bone fracture risk, but yielding contradictory results. The present study was conducted to evaluate whether the genetically predicted plasma HCY levels were causally associated with the change of BMD and the risk of bone fracture.

METHODS

Genetic summary statistics were extracted from genome-wide association study (GWAS) meta-analysis of plasma HCY levels (n = 44,147), GWAS meta-analyses of measured forearm (FA), femoral neck (FN) and lumbar spine (LS) BMD (n = up to 32,735), UK Biobank estimated heel BMD (eBMD) (n = 426,824) and fracture (n = 426,795) GWAS data. Two Sample Mendelian Randomization (TSMR) analysis was performed to assess the causal effects of genetically determined plasma HCY on the BMD and bone fractures.

RESULTS

The MR analysis indicated that, genetically decreased plasma HCY was associated with the increased FA-BMD based on the inverse variance weighting (IVW) method (standard deviation [SD] = 0.348, 95% CI: 0.146 to 0.550, P = 7 × 10^-4). However, there were no significant associations of genetically decreased plasma HCY with FN-BMD, LS-BMD, eBMD and the risk for bone fracture (SD = -0.041, 95% CI: -0.189 to 0.106, P = 0.582; SD = -0.053, 95% CI: -0.238 to 0.131, P = 0.572; SD = -0.030, 95% CI: -0.090 to 0.030, P = 0.328, odds ratio [OR]: 1.03, 95% CI: 0.94 to 1.13, P = 0.562, respectively). Moreover, the results also found that genetically determined HCY increase was not correlated with the changes of BMD and the risk for bone fracture.

CONCLUSION

Our study revealed that genetically decreased plasma HCY was associated with increase of FA-BMD.

Dietary betaine reduces plasma homocysteine concentrations and improves bone strength in laying hens

1. This study tested the hypothesis that the methyl-donor properties of betaine could reduce homocysteine concentrations, which has been recognised in a previous genetics study to be linked to bone quality. This was combined with phytase treatment, as phosphorus is critical for bone mineralisation.2. Using a 2 × 2 factorial arrangement, a total of 1920 Lohmann LSL-lite chickens housed as 24 replicates of 20 chickens were fed one of four diets containing dietary betaine (0 or 1000 mg/kg) and phytase (300 or 1000 FTU/kg) from one day old until end-of-lay. Blood and bone samples were collected at 45 and 70 weeks of age.3. Hens fed betaine had lower plasma homocysteine level (P < 0.05), higher tibia breaking strength (P < 0.05) and higher tibia bone density (P < 0.05).4. Egg production and quality was excellent throughout the study and were not affected by the dietary treatments.5. The addition of dietary betaine was successful at reducing plasma homocysteine concentrations and improving bone strength in laying hens, which could be used as an intervention to alleviate welfare concerns.

Gut microbiota and the periodontal disease: role of hyperhomocysteinemia

Periodontal disease is one of the most common conditions resulting from poor oral hygiene and is characterized by a destructive process in the periodontium that essentially includes gingiva, alveolar mucosa, cementum, periodontal ligament, and alveolar bone. Notably, the destructive event in the alveolar bone has been linked to homocysteine (Hcy) metabolism; however, it has not been fully investigated. Therefore; the implication of Hcy towards initiation, progression, and maintenance of the periodontal disease remains incompletely understood. Higher levels of Hcy (also known as hyperhomocysteinemia (HHcy)) exerts deleterious effects on gum health and teeth in distinct ways. Firstly, increased production of proinflammatory cytokines such as TNF-α, IL-1β, IL-6, and IL-8 leads to an inflammatory cascade of events that affect methionine (Met) and Hcy metabolism (i.e., 1-carbon metabolism) leading to HHcy. Secondly, metabolic dysregulation during chronic medical conditions increases systemic inflammation leading to a decrease in vitamins, more specifically B6, B12, and folic acid, that play important roles as cofactors in Hcy metabolism. Also, given the folate level in the HHcy state that is important during dysbiosis, these two conditions appear to be intimately related, and in this context, HHcy-induced dysbiosis may be one of the potential causes of periodontal disease. This paper sums up the link between periodontitis and HHcy, with a special emphasis on the "oral-gut microbiome axis" and the potential probiotic intervention towards warding off some of the serious periodontal disease conditions.

The role of cystatin C as a proteasome inhibitor in multiple myeloma

Objectives: Bone destruction and renal impairment are two frequent complications of multiple myeloma (MM). Cystatin C, an extracellular cysteine proteinase inhibitor, is encoded by the housekeeping gene CST3 and associated with human tumors. The role of cystatin C in multiple myeloma has been revealed recently. The purpose of this study was to explore the role of cystatin C as a proteasome inhibitor in multiple myeloma. Methods : A comprehensive literature review was conducted through Pubmed to summarize the published evidence on cystatin C in multiple myeloma. English literature sources since 1999 were searched, using the terms cystatin C, multiple myeloma. Results: cystatin C is a sensitive indicator for the diagnosis of myeloma nephropathy and has a dual role in myeloma bone disease. Also, cystatin C reflects tumor burden and is strongly associated with prognosis in patients with multiple myeloma. Conclusion: Cystatin C have great diagnostic and prognostic value in multiple myeloma. It can provide a new treatment direction for MM by designing and searching for antagonists of cystatin C or cysteine protease agonists using cystatin C as a therapeutic target.

Bone Mineral Density and Related Scores in Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Parkinson's disease (PD) is the second most common degenerative neurologic disorder in older adults, and increasing attention has been paid to bone health in PD. Although several studies have shown that patients with PD have a lower bone mineral density (BMD) than do non-PD controls, there have been no systematic reviews in recent years.

METHODS

PubMed, Medline, and Web of Science were used to search relevant studies up to May 2020. BMD, BMD T score, and BMD Z score of patients with and without PD were statistically analyzed. Meta-analysis was conducted using Review Manager version 5.3.

RESULTS

This meta-analysis included 17 studies comprising 10,289 individuals. In the meta-analysis, adults with PD had lower total body, total hip, total radius, lumbar spine, total femur, femur neck, right-hand, and left-hand BMD than did non-PD controls. The T score of total body BMD, total hip BMD, total radius BMD, lumbar spine BMD, L1-L4 spine BMD, total femur BMD, and femur neck BMD in adults with PD were lower than those in non-PD controls. Futhermore, the Z score of total body BMD, total hip BMD, total radius BMD, lumbar spine BMD, L1-L4 spine BMD, and femur neck BMD was lower in adults with PD than in non-PD controls.

CONCLUSIONS

Patients with PD had a lower BMD, BMD T score, and BMD Z score compared with non-PD controls. Therefore, clinicians should routinely monitor BMD of patients with PD to prevent falling and fragility fractures in older adults and optimize BMD before surgical treatment of severe spinal deformity caused by PD.

Effects of Neurological Disorders on Bone Health

Neurological diseases, particularly in the context of aging, have serious impacts on quality of life and can negatively affect bone health. The brain-bone axis is critically important for skeletal metabolism, sensory innervation, and endocrine cross-talk between these organs. This review discusses current evidence for the cellular and molecular mechanisms by which various neurological disease categories, including autoimmune, developmental, dementia-related, movement, neuromuscular, stroke, trauma, and psychological, impart changes in bone homeostasis and mass, as well as fracture risk. Likewise, how bone may affect neurological function is discussed. Gaining a better understanding of brain-bone interactions, particularly in patients with underlying neurological disorders, may lead to development of novel therapies and discovery of shared risk factors, as well as highlight the need for broad, whole-health clinical approaches toward treatment.

Homocysteine induces oxidative stress and ferroptosis of nucleus pulposus via enhancing methylation of GPX4

Homocysteine (Hcy) is an amino acid involved in gene methylation. Plasma concentration of Hcy is elevated in the pathological condition hyperhomocysteinemia (HHcy), which increases the risk of disorders of the vascular, nervous and musculoskeletal systems, including chondrocyte dysfunction. The present study aimed to explore the role of Hcy in intervertebral disc degeneration (IVDD), using a range of techniques. A clinical epidemiological study showed that HHcy is an independent risk factor for human IVDD. Cell culture using rat nucleus pulposus cells showed that Hcy promotes a degenerative cell phenotype (involving increased oxidative stress and cell death by ferroptosis) which is mediated by upregulated methylation of GPX4. An in-vivo mouse 'puncture' model of IVDD showed that folic acid (which is used to treat HHcy in humans) reduced the ability of diet-induced HHcy to promote IVDD. We conclude that Hcy upregulates oxidative stress and ferroptosis in the nucleus pulposus via enhancing GPX4 methylation, and is a new contributing factor in IVDD.

Pristimerin Inhibits Osteoclast Differentiation and Bone Resorption in vitro and Prevents Ovariectomy-Induced Bone Loss in vivo

Introduction

Osteoporosis is a metabolic bone disease characterized by reduced bone quantity and microstructure, typically owing to increased osteoclastogenesis and/or enhanced osteoclastic bone resorption, resulting in uncontrolled bone loss, which primarily affects postmenopausal women. In consideration of the severe side effects of current drugs for osteoporosis, new safe and effective medications are necessary. Pristimerin (Pri), a quinone methide triterpene extracted from Celastraceae and Hippocrateaceae members, exhibits potent antineoplastic and anti-inflammatory effects. However, its effect on osteoclasts remains unknown.

Materials and Methods

We evaluated the anti-osteoclastogenic and anti-resorptive effect of Pri on bone marrow-derived osteoclasts and its underlying mechanism in vitro. In addition, the protective effect of Pri on ovariectomy model was also explored in vivo.

Results

In vitro, Pri inhibited osteoclast differentiation and mature osteoclastic bone resorption in a time- and dose-dependent manner. Further, Pri suppressed the expression of osteoclast-related genes and the activation of key proteins. Pri also inhibited the early activation of ERK, JNK MAPK, and AKT signaling pathways in bone marrow-derived macrophages (BMMs), ultimately inhibiting the induction and activation of the crucial osteoclast transcriptional factor nuclear factor of activated T‐cell cytoplasmic 1 (NFATc1). In vivo, consistent with our in vitro data, Pri clearly prevented ovariectomy-induced bone loss.

Conclusion

Our data showed that Pri inhibits the differentiation and activation of osteoclasts in vitro and in vivo, and could be a promising candidate for treating osteoporosis.

Systems analysis of avascular necrosis of femoral head using integrative data analysis and literature mining delineates pathways associated with disease

Avascular necrosis of femoral head (AVNFH) is a debilitating disease, which affects the middle aged population. Though the disease is managed using bisphosphonate, it eventually leads to total hip replacement due to collapse of femoral head. Studies regarding the association of single nucleotide polymorphisms with AVNFH, transcriptomics, proteomics, metabolomics, biophysical, ultrastructural and histopathology have been carried out. Functional validation of SNPs was carried out using literature. An integrated systems analysis using the available datasets might help to gain further insights into the disease process. We have carried out an analysis of transcriptomic data from GEO-database, SNPs associated with AVNFH, proteomic and metabolomic data collected from literature. Based on deficiency of vitamins in AVNFH, an enzyme-cofactor network was generated. The datasets are analyzed using ClueGO and the genes are binned into pathways. Metabolomic datasets are analyzed using MetaboAnalyst. Centrality analysis using CytoNCA on the data sets showed cystathionine beta synthase and methylmalonyl-CoA-mutase to be common to 3 out of 4 datasets. Further, the genes common to at least two data sets were analyzed using DisGeNET, which showed their involvement with various diseases, most of which were risk factors associated with AVNFH. Our analysis shows elevated homocysteine, hypoxia, coagulation, Osteoclast differentiation and endochondral ossification as the major pathways associated with disease which correlated with histopathology, IHC, MRI, Micro-Raman spectroscopy etc. The analysis shows AVNFH to be a multi-systemic disease and provides molecular signatures that are characteristic to the disease process.

GSH attenuates RANKL-induced osteoclast formation in vitro and LPS-induced bone loss in vivo

Osteoclasts are capable of adhering the bone matrix, then secrete acid and lytic enzymes to resorb it. Reactive oxygen species (ROS), as a signaling messenger, plays an important role in the receptor activator nuclear factor κB ligand (RANKL) signal pathway during osteoclast differentiation. Glutathione (GSH) is known to be a powerful antioxidant which can scavenge intracellular ROS. This study aimed to investigate whether GSH can as a protective agent against the RANKL-stimulated osteoclastogenesis by suppressing intracellular ROS. Here, we showed that GSH markedly restricted RNAKL-induced differentiation of bone marrow-derived macrophages (BMMs) to form osteoclasts. GSH suppressed RANKL-induced ROS generation and subsequent ROS-induced NF-κB signaling pathways within BMMs during osteoclastogenesis. Further, GSH acted to significantly downregulate the osteoclastogenic genes expression of nuclear factor in activated T cells, cytoplasmic1 (NFATc1), C-fos, the tartrate-resistant acid phosphatase (TRAP), and osteoclast-associated immunoglobulin-like receptor (OSCAR). Our results suggested that GSH inhibits intracellular ROS-mediated NF-κB signal pathway involved in osteoclast differentiation. These findings might form the basis of a new strategy for treating bone disease associated with excessive bone resorption.

Vindoline Inhibits RANKL-Induced Osteoclastogenesis and Prevents Ovariectomy-Induced Bone Loss in Mice

Osteolytic bone diseases, for example postmenopausal osteoporosis, arise from the imbalances between osteoclasts and osteoblasts in the bone remodeling process, whereby osteoclastic bone resorption greatly exceeds osteoblastic bone formation resulting in severe bone loss and deterioration in bone structure and microarchitecture. Therefore, the identification of agents that can inhibit osteoclast formation and/or function for the treatment of osteolytic bone disease has been the focus of bone and orthopedic research. Vindoline (Vin), an indole alkaloid extracted from the medicinal plant Catharanthus roseus, has been shown to possess extensive biological and pharmacological benefits, but its effects on bone metabolism remains to be documented. Our study demonstrated for the first time, that Vin could inhibit osteoclast differentiation from bone marrow macrophages (BMMs) precursor cells as well as mature osteoclastic bone resorption. We further determined that the underlying molecular mechanism of action of Vin is in part due to its inhibitory effect against the activation of MAPK including p38, JNK, and ERK and intracellular reactive oxygen species (ROS) production. This effect ultimately suppressed the induction of c-Fos and NFATc1, which consequently downregulated the expression of the genes required for osteoclast formation and bone resorption. Consistent with our in vitro findings, in vivo administration of Vin protected mice against ovariectomy (OVX)-induced bone loss and trabecular bone deterioration. These results provided promising evidence for the potential therapeutic application of Vin as a novel treatment option against osteolytic diseases.

Inhibition of the negative effect of high glucose on osteogenic differentiation of bone marrow stromal cells by silicon ions from calcium silicate bioceramics

Human bone marrow stem cells (hBMSCs) are exploited for miscellaneous applications in bone tissue engineering where they are mainly used as seed cells. However, high glucose (HG) environment has negative impacts on the proliferation and osteogenic differentiation of hBMSCs, thus reducing the bone formation in diabetic patients. In our former research works, we discovered that silicon (Si) ions extracted from silicate-based bioceramics are able to stimulate the proliferation and osteogenic differentiation of hBMSCs under normal culture condition. This study aimed to investigate if Si ions could prevent HG-induced inhibition of proliferation and osteogenesis of hBMSCs. We found that 2.59 ppm concentration of Si ions promoted the proliferation of hBMSCs under HG condition. The results from alkaline phosphatase (ALP) activity assay, Alizarin red S staining and quantitative real-time PCR analysis of osteogenic genes (BMP2, RUNX2, ALP, COL1 and OCN) demonstrated that the 15.92 ppm concentration of Si ions prevented HG-induced inhibition of the osteogenic differentiation of hBMSCs. Moreover, application of Si ions reduced the level of reactive oxygen species in HG-treated hBMSCs. In HG-treated hBMSCs following 15.92 ppm Si ions treatment, activation of BMP2/SMAD signaling pathway was detected, as indicated by the increased expression of BMP2 receptors and its downstream genes such as SMAD1, SMAD4 and SMAD5. Taken together, we provide evidence that the specific concentration of Si ions compensated HG-induced inhibition of proliferation and osteogenic differentiation of hBMSCs through antioxidant effect and modulation of BMP2/SMAD pathway. The results suggest that silicate-based bioceramics might be good scaffold biomaterials for bone engineering applications in diabetes patients.

PAI-1 contributes to homocysteine-induced cellular senescence

Cellular Senescence is associated with organismal aging and related pathologies. Previously, we reported that plasminogen activator inhibitor-1 (PAI-1) is an essential mediator of senescence and a potential therapeutic target for preventing aging-related pathologies. In this study, we investigate the efficacies of PAI-1 inhibitors in both in vitro and in vivo models of homocysteine (Hcy)-induced cardiovascular aging. Elevated Hcy, a known risk factor of cardiovascular diseases, induces endothelial senescence as evidenced by increased senescence-associated β-Gal positivity (SA-β-Gal), flattened cellular morphology, and cylindrical appearance of cellular nuclei. Importantly, inhibition of PAI-1 by small molecule inhibitors reduces the number of SA-β-Gal positive cells, normalizes cellular morphology and nuclear shape. Furthermore, while Hcy induces the levels of senescence regulators PAI-1, p16, p53 and integrin β3, and suppresses catalase expression, treatment with PAI-1 inhibitors blocks the Hcy-induced stimulation of senescence cadres, and reverses the Hcy-induced suppression of catalase, indicating that PAI-1 specific small molecule inhibitors are efficient to prevent Hcy-induced cellular senescence. Our in vivo study shows that the levels of integrin β3, a recently identified potential regulator of cellular senescence, and its interaction with PAI-1 are significantly elevated in Hcy-treated heart tissues. In contrast, Hcy suppresses antioxidant gene regulator Nrf2 expression in hearts. However, co-treatment with PAI-1 inhibitor completely blocks the stimulation of Hcy-induced induction of integrin β3 and reverses Nrf2 expression. Collectively these in vitro and in vivo studies indicate that pharmacological inhibition of PAI-1 improves endothelial and cardiac health by suppressing the pro-senescence effects of hyperhomocysteinemia through suppression of Hcy-induced master regulators of cellular senescence PAI-1 and integrin β3. Therefore, PAI-1 inhibitors are promising drugs for amelioration of hyperhomocysteinemia-induced vascular aging and aging-related disease.

Diosmetin inhibits osteoclast formation and differentiation and prevents LPS-induced osteolysis in mice

Osteolytic bone diseases are closely linked to the over-activation of osteoclasts and enhancement of bone resorption. It has become a major health issue in orthopedic practice worldwide. Inhibition of osteoclasts is proposed to be the main treatment for osteolytic disorders. Diosmetin (DIO) is a natural flavonoid with properties of antioxidant, anti-infection, and antishock. The effect of DIO on osteoclast differentiation is poorly understood. In this study project, we found that DIO could inhibit osteoclastic formation induced by receptor activator of nuclear factor kappa-B ligand (RANKL) in a dose-dependent manner. The expression of the osteoclast differentiation marker genes, cathepsin K, nuclear factor of activated T-cells 1 (NFATc1), Acp5, Ctr, Atp6v0d2, and Mmp9 were also decreased by the treatment of DIO. In addition, DIO attenuated the formation of actin ring and the ability of bone resorption. Further, the western blotting showed that DIO inhibits the phosphorylation of the mitogen-activated protein kinases signaling pathway induced by RANKL, accompanied by the downregulation of NFATc1 and c-Fos expression. We also found that DIO could reduce the accumulation of reactive oxygen species (ROS) induced by RANKL. In vivo, the study revealed that DIO can significantly reduce LPS-induced osteolysis in mice. Collectively, our study shows that DIO can inhibit osteoclast formation and activation, and could serve as a potential therapeutic drug for osteolytic bone diseases.

Global urinary metabolic profiling of the osteonecrosis of the femoral head based on UPLC-QTOF/MS

INTRODUCTION

Osteonecrosis of the femoral head (ONFH), one of the widespread orthopedic diseases with a decrease in bloodstream to the femoral head, is frequently accompanied by cellular death, trabecula fracture, and collapse of the articular surface. The exactly pathological mechanism of ONFH remains to explore and further identify.

OBJECTIVES

The aim was to identify the global urinary metabolic profiling of ONFH and to detect biomarkers of ONFH.

METHODS

Urine samples were collected from 26 ONFH patients and 26 healthy people. Ultra-performance liquid chromatography-quadrupole time of flight tandem mass spectrometry (UPLC-QTOF/MS) in combination with multivariate statistical analysis was developed and performed to identify the global urinary metabolic profiling of ONFH.

RESULTS

The urinary metabolic profiling of ONFH group was significantly separated from the control group by multivariate statistical analysis. 33 distinctly differential metabolites were detected between the ONFH patients and healthy people. Sulfate, urea, Deoxycholic acid and PE(14:0/14:1(9Z)) were screened as the potential biomarkers of ONFH. In addition, the up/down-regulation of sulfur metabolism, cysteine and methionine metabolism, glycerophospholipid metabolism, and histidine metabolism were clearly be associated with the ONFH pathogenic progress.

CONCLUSION

Our results suggested that metabolomics could serve as a promising approach for identifying the diagnostic biomarkers and elucidating the pathological mechanism of ONFH.

Homocysteine and age-associated disorders

There are numerous theories of aging, a process which still seems inevitable. Aging leads to cancer and multi-systemic disorders as well as chronic diseases. Decline in age- associated cellular functions leads to neurodegeneration and cognitive decline that affect the quality of life. Accumulation of damage, mutations, metabolic changes, failure in cellular energy production and clearance of altered proteins over the lifetime, and hyperhomocysteinemia, ultimately result in tissue degeneration. The decline in renal functions, nutritional deficiencies, deregulation of methionine cycle and deficiencies of homocysteine remethylation and transsulfuration cofactors cause elevation of homocysteine with advancing age. Abnormal accumulation of homocysteine is a risk factor of cardiovascular, neurodegenerative and chronic kidney disease. Moreover, approximately 50% of people, aged 65 years and older develop hypertension and are at a high risk of developing cardiovascular insufficiency and incurable neurodegenerative disorders. Increasing evidence suggests inverse relation between cognitive impairment, cerebrovascular and cardiovascular events and renal function. Oxidative stress, inactivation of nitric oxide synthase pathway and mitochondria dysfunction associated with impaired homocysteine metabolism lead to aging tissue degeneration. In this review, we examine impact of high homocysteine levels on changes observed with aging that contribute to development and progression of age associated diseases.

Hydrogen Sulfide Promotes Bone Homeostasis by Balancing Inflammatory Cytokine Signaling in CBS-Deficient Mice through an Epigenetic Mechanism

Previously, we have shown hyperhomocysteinemia (HHcy) to have a detrimental effect on bone remodeling, which is associated with osteoporosis. During transsulfuration, Hcy is metabolized into hydrogen sulfide (H₂S), a gasotransmitter molecule known to regulate bone formation. Therefore, in the present study, we examined whether H₂S ameliorates HHcy induced epigenetic and molecular alterations leading to osteoporotic bone loss. To test this mechanism, we employed cystathionine-beta-synthase heterozygote knockout mice, fed with a methionine rich diet (CBS^+/− +Met), supplemented with H₂S-donor NaHS for 8 weeks. Treatment with NaHS, normalizes plasma H₂S, and completely prevents trabecular bone loss in CBS^+/− mice. Our data showed that HHcy caused inhibition of HDAC3 activity and subsequent inflammation by imbalancing redox homeostasis. The mechanistic study revealed that inflammatory cytokines (IL-6, TNF-α) are transcriptionally activated by an acetylated lysine residue in histone (H3K27ac) of chromatin by binding to its promoter and subsequently regulating gene expression. A blockade of HDAC3 inhibition in CBS^+/− mice by HDAC activator ITSA-1, led to the remodeling of histone landscapes in the genome and thereby attenuated histone acetylation-dependent inflammatory signaling. We also confirmed that RUNX2 was sulfhydrated by administration of NaHS. Collectively, restoration of H₂S may provide a novel treatment for CBS-deficiency induced metabolic osteoporosis.

The Effects of Homocysteine on the Skeleton

PURPOSE OF REVIEW

Homocystinuria is a congenital metabolic disorder in which cystathionine β-synthase deficiency results in a prominent increase in homocysteine (serum levels > 100 μM), causing mental retardation, atherosclerotic cerebral infarction, and osteoporosis accompanied by fragility fractures. Encountering a case with excessive homocysteinemia such as that seen in hereditary homocystinuria is unlikely during usual medical examinations. However, in individuals who have vitamin B or folate deficiency, serum homocysteine concentrations are known to increase. These individuals may also have a polymorphism in methylenetetrahydrofolate reductase, MTHFR (C677T: TT type), which regulates homocysteine metabolism. These changes in homocysteine levels may elicit symptoms resembling those of homocystinuria (e.g., Alzheimer's disease, atherosclerosis, osteoporosis).

RECENT FINDINGS

High serum homocysteine has been shown to have detrimental effects on neural cells, vascular endothelial cells, osteoblasts, and osteoclasts. Homocysteine is also known to increase oxidative stress, disrupt cross-linking of collagen molecules, and increase levels of advanced glycation end products, which results in reduced bone strength through a mechanism that goes beyond low bone density and increased bone resorption. Therefore, high serum homocysteine may be regarded as a factor that can reduce both bone mass and impair bone quality. In this review, we outline the epidemiology and pathophysiology of osteoporosis associated with hyperhomocysteinemia.

Hydrogen sulfide epigenetically mitigates bone loss through OPG/RANKL regulation during hyperhomocysteinemia in mice

Hydrogen sulfide (H2S) is a novel gasotransmitter produced endogenously in mammalian cells, which works by mediating diverse physiological functions. An imbalance in H2S metabolism is associated with defective bone homeostasis. However, it is unknown whether H2S plays any epigenetic role in bone loss induced by hyperhomocysteinemia (HHcy). We demonstrate that diet-induced HHcy, a mouse model of metabolite induced osteoporosis, alters homocysteine metabolism by decreasing plasma levels of H2S. Treatment with NaHS (H2S donor), normalizes the plasma level of H2S and further alleviates HHcy induced trabecular bone loss and mechanical strength. Mechanistic studies have shown that DNMT1 expression is higher in the HHcy condition. The data show that activated phospho-JNK binds to the DNMT1 promoter and causes epigenetic DNA hyper-methylation of the OPG gene. This leads to activation of RANKL expression and mediates osteoclastogenesis. However, administration of NaHS could prevent HHcy induced bone loss. Therefore, H2S could be used as a novel therapy for HHcy mediated bone loss.

A Metabolomics Study on the Bone Protective Effects of a Lignan-Rich Fraction From Sambucus Williamsii Ramulus in Aged Rats

The lignan-rich fraction (SWR) of Sambucus Williamsii Ramulus, a folk herbal medicine in China for treatment of bone diseases, has previously reported to exert protective effects on bone without exerting uterotrophic effects in ovariectomized (OVX) mice. The aim of the present study was to identify the potential metabolites and the associated metabolic pathways that contribute to the beneficial effects of SWR on bone in vivo. Aged female Sprague Dawley rats (9 months old) were either sham-operated or ovariectomized for 12 weeks, before receiving treatment for another 12 weeks with the following treatment groups (n = 12 each): vehicle (Sham), vehicle (OVX), Premarin (130 μg/kg) or low (57 mg/kg), medium (114 mg/kg), and high (228 mg/kg) doses of SWR. The results showed that SWRH significantly suppressed bone loss, improved bone micro-architecture and increased bone strength on tibia without stimulating uterus weight gain in OVX rats. Premarin exerted similar bone protective effects as SWRH but elicited uterotrophic effects in OVX rats. The metabolic profiles of serum samples were analyzed by using ultra-performance liquid chromatography quadrupole time-of flight mass spectrometry and gas chromatography time-of flight mass spectrometry, and the metabolites that were significantly altered were identified by multivariate statistical analysis. Our study indicated that SWRH effectively restored the changes of 26 metabolites induced by estrogen-deficiency in OVX rats, which related to lipids, amino acids, tryptophan metabolisms, and anti-oxidative system. A subsequent validation showed that the serum level of superoxide dismutase and catalase were indeed up-regulated, while the serotonin level in a tryptophan hydroxylase 1 (TPH1) high expressing cells (rats RBL-2H3 cells) was down regulated after treatment with SWR. The results also suggested that the gut-microbiota may play an important role on the bone protective effects of SWR. The current study provides insight for understanding the unique mechanism of actions of SWR that might be involved in achieving bone protective effects in vivo.

Parkinson's disease and the risk of osteoporotic vertebral compression fracture: a nationwide population-based study

Patients with Parkinson's disease (PD) were at higher risk of osteoporotic vertebral compression fractures (OVCF) compared to controls and had elevated mortality rates. Compared to conservative treatment, surgical treatment for OVCF in PD patients seemed to be associated with better outcomes.

INTRODUCTION

The purpose of this study was to evaluate the risk of OVCF in patients with PD.

METHODS

Data from patients over the age of 60 years who were diagnosed with PD were collected between 2004 and 2013 from the Korean National Health Insurance Database (n = 3370). The comparison group (non-PD) consisted of randomly selected patients (five per patient with PD; n = 16,850) matched to the PD group, who were newly diagnosed annually according to age and sex. Cox proportional hazard regressions were used to examine the relationships between osteoporosis, OVCF, surgery for OVCF, and PD. Household income and residential area of patients were also assessed. Overall survival rates were calculated after adjusting for confounding factors, such as hypertension, diabetes mellitus, and chronic kidney disease.

RESULTS

OVCF was developed in 12.5% of patients in the PD group and in 7.4% of patients in the control group. PD was associated with increased risk of osteoporosis (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.21-1.43; p < 0.001), OVCF (HR 1.66; 95% CI, 1.47-1.87; p < 0.001), and surgery for OVCF (HR 2.69; 95% CI, 1.78-4.08; p < 0.001). Household income was not significantly related with development of osteoporosis, incidence of OVCF, or surgery for OVCF. Residential area was statistically associated with osteoporosis, OVCF, and surgery for OVCF. The mortality rate of the PD group was about 1.7 times higher than that of the non-PD group after adjusting for potential confounders, and the mortality rate of the PD with OVCF group was higher than that of the non-PD group, but not significantly (p = 0.09). The survival rate of the PD group with surgery for OVCF showed a trend toward a more positive prognosis compared with that of the PD group with conservative treatment.

CONCLUSIONS

Patients with PD had significantly increased risk of osteoporosis and OVCF. Surgical treatment for OVCF in PD patients was associated with a better prognosis than conservative treatment.

Homocysteine induces oxidative stress to damage trabecular meshwork cells

The aim of the present study was to investigate the effect of homocysteine (Hcy) in on human trabecular meshwork cells (HTMCs). A total of 41 patients with primary open-angle glaucoma (POAG) and 53 patients with senile cataracts (control group) were recruited. Plasma and aqueous humor samples were collected and the Hcy concentrations were determined using enzymatic cycling assays. In cell experiments, normal HTMCs were passaged and randomly divided into a blank control group, a normal HTMC group and experimental groups, which were treated with different concentrations of Hcy. The HTMC activities were detected using the Cell Counting Kit-8 method and the HTMC mitochondrial membrane potential (MMP) was detected using JC-1 staining. Reactive oxygen species (ROS) released by trabecular meshwork cells was detected using flow cytometry and superoxide dismjutase-1 (SOD1) expression was detected using immunoblotting. The results revealed that the concentration of Hcy in the plasma and aqueous humor of the POAG group (14.44±0.86 and 1.60±0.27 µmol/l, respectively) was significantly higher compared with the control group (10.82±0.29 and 0.69±0.39 µmol/l). All tested concentrations (30, 100, 300 and 1,000 µmol/l) of Hcy reduced the MMP in HTMCs and inhibited HTMC proliferation in a dose-dependent manner. ROS production by HTMCs significantly increased with increased concentrations of Hcy, whereas SOD1 expression significantly decreased in a dose-dependent manner. In summary, patients with POAG were demonstrated to have increased concentrations of Hcy in the plasma and aqueous humor. High concentrations of Hcy in HTMCs induced an oxidative stress state, thereby further inhibiting HTMC proliferation. The results of the present study demonstrate that Hcy may be a potential treatment target in patients with POAG.

Homocysteine causes dysfunction of chondrocytes and oxidative stress through repression of SIRT1/AMPK pathway: A possible link between hyperhomocysteinemia and osteoarthritis

Emerging evidence has indicated that the perturbed expression of homocysteine (Hcy) may induce mitochondrial dysfunction and disturb bone metabolism. Sirtuin 1 (SIRT1) and AMP-activated protein kinase (AMPK) are two critical sensors that regulate mitochondrial biogenesis and have been recognized as therapeutic targets in osteoarthritis (OA). This study was designed to test whether Hcy caused pro-osteoarthritic changes through modulation of SIRT1 and AMPK. Our results showed that administration of Hcy reduced the SIRT1/AMPK/PGC-1α signaling in chondrocytes, leading to mitochondrial dysfunction as a result of increased oxidative stress and apoptosis. Moreover, we demonstrated that the expression of NF-κB, COX-2, IL-8, and MMP-13 were elevated subsequent to inhibition of SIRT1/AMPK/PGC-1α/PPAR-γ pathway by homocysteine, thereby causing detrimental effects on chondrocytes. In the animal model of diet-induced hyperhomocysteinemia (HHcy), we observed the similar findings that SIRT1/PGC-1α/PPAR-γ cascades were downregulated with elevated MMP-13 and COX-2. Taken together, data from the current study revealed that the reduced SIRT1 by Hcy may contribute to degradative cartilage process, which provided insight into the etiology of OA.