Chronic alcohol ingestion induces osteoclastogenesis and bone loss through IL-6 in mice

Alcohol Intake and Prevalent Kidney Stone: The National Health and Nutrition Examination Survey 2007-2018

The association of alcohol intake with kidney stone disease (KSD) is not clear based on current clinical evidence. We examined the National Health and Nutrition Examination Survey (NHANES) 2007-2018 and used logistic regression analyses to determine the independent association between alcohol intake and prevalent KSD. In total, 29,684 participants were eligible for the final analysis, including 2840 prevalent stone formers (SFs). The mean alcohol intake was 37.0 ± 2.4 g/day among SFs compared to 42.7 ± 0.9 among non-SFs (p = 0.04). Beer [odds ratio (OR) = 0.76, 95% CI: 0.61-0.94, p = 0.01] and wine (OR = 0.75, 95% CI: 0.59-0.96, p = 0.03) intakes were strongly associated with lower odds of prevalent KSD, while liquor intake had no association. Furthermore, the effects of beer and wine intakes on stone formation were dose-dependent. The OR for comparing participants drinking 1-14 g/day of beer to non-drinkers was 1.41 (95%CI: 0.97-2.05, p = 0.07), that of >14-≤28 g/day of beer to non-drinkers was 0.65 (95% CI: 0.42-1.00, p = 0.05), that of >28-≤56 g/day of beer to non-drinkers was 0.60 (95% CI: 0.39-0.93, p = 0.02), and that of >56 g/day of beer to non-drinkers was 0.34 (95% CI: 0.20-0.57, p < 0.001). Interestingly, the effect of wine intake was only significant among participants drinking moderate amounts (>14-28 g/day), with an OR of 0.54 (95% CI: 0.36-0.81, p = 0.003) compared to non-drinkers, but this effect was lost when comparing low-level (1-14 g/day) and heavy (>28 g/day) wine drinkers to non-drinkers. These effects were consistent in spline models. This study suggests that both moderate to heavy beer intake and moderate wine intake are associated with a reduced risk of KSD. Future prospective studies are needed to clarify the causal relationship.

Impaired Osteogenesis in Human Induced Pluripotent Stem Cells with Acetaldehyde Dehydrogenase 2 Mutations

Acetaldehyde dehydrogenase 2 (ALDH2) is the second enzyme involved in the breakdown of acetaldehyde into acetic acid during the process of alcohol metabolism. Roughly 40% of East Asians carry one or two ALDH2*2 alleles, and the presence of ALDH2 genetic mutations in individuals may affect the bone remodeling cycle owing to accumulation of acetaldehyde in the body. In this study, we investigated the effects of ALDH2 mutations on bone remodeling. In this study, we examined the effects of ALDH2 polymorphisms on in vitro osteogensis using human induced pluripotent stem cells (hiPSCs). We differentiated wild-type (ALDH2*1/*1-) and ALDH2*1/*2-genotyped hiPSCs into osteoblasts (OBs) and confirmed their OB characteristics. Acetaldehyde was administered to confirm the impact caused by the mutation during OB differentiation. Calcium deposits formed during osteogenesis were significantly decreased in ALDH2*1/*2 OBs. The expression of osteogenic markers were also decreased in acetaldehyde-treated OBs differentiated from the ALDH2*1/*2 hiPSCs. Furthermore, the impact of ALDH2 polymorphism and acetaldehyde-induced stress on inflammatory factors such as 4-hydroxynonenal and tumor necrosis factor α was confirmed. Our findings suggest that individuals with ALDH2 deficiency may face challenges in acetaldehyde breakdown, rendering them susceptible to disturbances in normal bone remodeling therefore, caution should be exercised regarding alcohol consumption. In this proof-of-concept study, we were able to suggest these findings as a result of a disease-in-a-dish concept using hiPSCs derived from individuals bearing a certain mutation. This study also shows the potential of patient-derived hiPSCs for disease modeling with a specific condition.

Osteoclasts control endochondral ossification via regulating acetyl-CoA availability

Osteoclast is critical in skeletal development and fracture healing, yet the impact and underlying mechanisms of their metabolic state on these processes remain unclear. Here, by using osteoclast-specific small GTPase Rheb1-knockout mice, we reveal that mitochondrial respiration, rather than glycolysis, is essential for cathepsin K (CTSK) production in osteoclasts and is regulated by Rheb1 in a mechanistic target of rapamycin complex 1 (mTORC1)-independent manner. Mechanistically, we find that Rheb1 coordinates with mitochondrial acetyl-CoA generation to fuel CTSK, and acetyl-CoA availability in osteoclasts is the central to elevating CTSK. Importantly, our findings demonstrate that the regulation of CTSK by acetyl-CoA availability is critical and may confer a risk for abnormal endochondral ossification, which may be the main cause of poor fracture healing on alcohol consumption, targeting Rheb1 could successfully against the process. These findings uncover a pivotal role of mitochondria in osteoclasts and provide a potent therapeutic opportunity in bone disorders.

Less sclerotic microarchitecture pattern with increased bone resorption in glucocorticoid-associated osteonecrosis of femoral head as compared to alcohol-associated osteonecrosis of femoral head

BACKGROUND

Glucocorticoid usage and alcohol abuse are the most widely accepted risk factors for nontraumatic osteonecrosis of femoral head (ONFH). Despite distinct etiologies between glucocorticoid-associated ONFH (GONFH) and alcohol-associated ONFH (AONFH), little is known about the differences of the microarchitectural and histomorphologic characteristics between these subtypes of ONFH.

PURPOSES

To investigate bone microarchitecture, bone remodeling activity and histomorphology characteristics of different regions in femoral heads between GONFH and AONFH.

METHODS

From September 2015 to October 2020, 85 patients diagnosed with GONFH and AONFH were recruited. Femoral heads were obtained after total hip replacement. Femoral head specimens were obtained from 42 patients (50 hips) with GONFH and 43 patients (50 hips) with AONFH. Micro-CT was utilized to assess the microstructure of 9 regions of interest (ROIs) in the femoral head. Along the supero-inferior orientation, the femoral head was divided into necrotic region, reactive interface, and normal region; along the medio-lateral orientation, the femoral head was divided into medial region, central region and lateral region. Decalcified and undecalcified bone histology was subsequently performed to evaluate histopathological alterations and bone remodeling levels.

RESULTS

In the necrotic region, most of the microarchitectural parameters did not differ significantly between GONFH and AONFH, whereas both the reactive interface and normal region revealed a less sclerotic microarchitecture but a higher bone remodeling level in GONFH than AONFH. Despite similar necrotic pathological manifestations, subchondral trabecular microfracture in the necrotic region was more severe and vasculature of the reactive interface was more abundant in GONFH.

CONCLUSIONS

GONFH and AONFH shared similar microarchitecture and histopathological features in the necrotic region, while GONFH exhibited a less sclerotic microarchitecture and a more active bone metabolic status in both the reactive interface and normal region. These differences between GONFH and AONFH in bone microarchitectural and histopathological characteristics might contribute to the development of disease-modifying prevention strategies and treatments for ONFH, taking into etiologies.

A20 controls RANK-dependent osteoclast formation and bone physiology

The anti-inflammatory protein A20 serves as a critical brake on NF-κB signaling and NF-κB-dependent inflammation. In humans, polymorphisms in or near the TNFAIP3/A20 gene have been associated with several inflammatory disorders, including rheumatoid arthritis (RA), and experimental studies in mice have demonstrated that myeloid-specific A20 deficiency causes the development of a severe polyarthritis resembling human RA. Myeloid A20 deficiency also promotes osteoclastogenesis in mice, suggesting a role for A20 in the regulation of osteoclast differentiation and bone formation. We show here that osteoclast-specific A20 knockout mice develop severe osteoporosis, but not inflammatory arthritis. In vitro, osteoclast precursor cells from A20 deficient mice are hyper-responsive to RANKL-induced osteoclastogenesis. Mechanistically, we show that A20 is recruited to the RANK receptor complex within minutes of ligand binding, where it restrains NF-κB activation independently of its deubiquitinating activity but through its zinc finger (ZnF) 4 and 7 ubiquitin-binding functions. Together, these data demonstrate that A20 acts as a regulator of RANK-induced NF-κB signaling to control osteoclast differentiation, assuring proper bone development and turnover.

Leukemia inhibitory factor is a therapeutic target for renal interstitial fibrosis

BACKGROUND

The role of the IL6 family members in organ fibrosis, including renal interstitial fibrosis (TIF), has been widely explored. However, few studies have ever simultaneously examined them in the same cohort of patients. Besides, the role of leukemia inhibitory factor (LIF) in TIF remains unclear.

METHODS

RNA-seq data of kidney biopsies from chronic kidney disease (CKD) patients, in both public databases and our assays, were used to analyze transcript levels of IL6 family members. Two TIF mouse models, the unilateral ureteral obstruction (UUO) and the ischemia reperfusion injury (IRI), were employed to validate the finding. To assess the role of LIF in vivo, short hairpin RNA, lenti-GFP-LIF was used to knockdown LIF receptor (LIFR), overexpress LIF, respectively. LIF-neutralizing antibody was used in therapeutic studies. Whether urinary LIF could be used as a promising predictor for CKD progression was investigated in a prospective observation patient cohort.

FINDINGS

Among IL6 family members, LIF is the most upregulated one in both human and mouse renal fibrotic lesions. The mRNA level of LIF negatively correlated with eGFR with the strongest correlation and the smallest P value. Baseline urinary concentrations of LIF in CKD patients predict the risk of CKD progression to end-stage kidney disease by Kaplan-Meier analysis. In mouse TIF models, knockdown of LIFR alleviated TIF; conversely, overexpressing LIF exacerbated TIF. Most encouragingly, visible efficacy against TIF was observed by administering LIF-neutralizing antibodies to mice. Mechanistically, LIF-LIFR-EGR1 axis and Sonic Hedgehog signaling formed a vicious cycle between fibroblasts and proximal tubular cells to augment LIF expression and promote the pro-fibrotic response via ERK and STAT3 activation.

INTERPRETATION

This study discovered that LIF is a noninvasive biomarker for the progression of CKD and a potential therapeutic target of TIF.

FUNDINGS

Stated in the Acknowledgements section of the manuscript.

Comparison of the inhibitory effect of tocilizumab and etanercept on the progression of joint erosion in rheumatoid arthritis treatment

We compared the efficacy of tocilizumab and etanercept in inhibiting radiographic progression of joint destruction in rheumatoid arthritis. Overall, 187 patients treated with etanercept or tocilizumab were selected. To adjust for baseline patient characteristics between the tocilizumab and etanercept treatment groups, a propensity score matching was performed. Radiographic progression of joint destruction was compared between patients treated with tocilizumab or etanercept. Clinical disease activity index (CDAI) and modified health assessment questionnaire (mHAQ) scores at the administration of biologic treatment and after 12 months of tocilizumab and etanercept therapy were measured and compared to radiographical parameters between the groups. Levels of C-reactive protein (CRP), matrix metalloproteinase-3 (MMP-3), CDAI, and mHAQ scores improved after 12 months of treatment in the two groups. Proportion of patients with no Sharp erosion score progression was significantly higher with tocilizumab treatment than with etanercept treatment (p = 0.032). Multivariate analysis demonstrated that Sharp erosion score was significantly associated with baseline CDAI (odds ratio, 1.05; 95% confidence interval, 1.003-1.099, p = 0.037). Tocilizumab treatment suppressed joint erosion progression compared to etanercept, and the progression correlated with baseline CDAI.

Alcohol Increases Lung Angiotensin-Converting Enzyme 2 Expression and Exacerbates Severe Acute Respiratory Syndrome Coronavirus 2 Spike Protein Subunit 1-Induced Acute Lung Injury in K18-hACE2 Transgenic Mice

During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, alcohol consumption increased markedly. Nearly one in four adults reported drinking more alcohol to cope with stress. Chronic alcohol abuse is now recognized as a factor complicating the course of acute respiratory distress syndrome and increasing mortality. To investigate the mechanisms behind this interaction, a combined acute respiratory distress syndrome and chronic alcohol abuse mouse model was developed by intratracheally instilling the subunit 1 (S1) of SARS-CoV-2 spike protein (S1SP) in K18-human angiotensin-converting enzyme 2 (ACE2) transgenic mice that express the human ACE2 receptor for SARS-CoV-2 and were kept on an ethanol diet. Seventy-two hours after S1SP instillation, mice on an ethanol diet showed a strong decrease in body weight, a dramatic increase in white blood cell content of bronchoalveolar lavage fluid, and an augmented cytokine storm, compared with S1SP-treated mice on a control diet. Histologic examination of lung tissue showed abnormal recruitment of immune cells in the alveolar space, abnormal parenchymal architecture, and worsening Ashcroft score in S1SP- and alcohol-treated animals. Along with the activation of proinflammatory biomarkers [NF-κB, STAT3, NLR family pyrin domain-containing protein 3 (NLRP3) inflammasome], lung tissue homogenates from mice on an alcohol diet showed overexpression of ACE2 compared with mice on a control diet. This model could be useful for the development of therapeutic approaches against alcohol-exacerbated coronavirus disease 2019.

Sclerostin in Excessive Drinkers: Relationships with Liver Function and Body Composition

Background: Sclerostin was initially described as an inhibitor of the Wnt-β catenin bone-forming pathway, but it also exerts important effects on intermediate metabolism and body composition. Osteosarcopenia and altered body fat distribution are common findings in excessive drinkers. The role of sclerostin in these patients is uncertain. We aim to analyze the behavior of sclerostin in excessive drinkers and its relationships with body composition (fat mass, lean mass, bone mass), handgrip strength, body mass index (BMI), liver function and ethanol intake. Methods: 107 male active heavy drinkers and 26 age-matched controls were included. Serum sclerostin was determined by ELISA. Body composition analysis was performed by double X-ray absorptiometry. Handgrip strength was recorded using a dynamometer. Liver function was assessed according to Child’s classification. Results: Sclerostin was higher among Child’s C patients, keeping a relationship with deranged liver function. Obesity, defined according to BMI, and body fat were strongly related to sclerostin, being independent of serum creatinine and of liver function. The relationship of sclerostin with total hip bone mineral density was displaced by BMI. Conclusion: Deranged liver function is associated with higher sclerostin levels in alcoholics. Raised sclerostin levels are related to fat deposition and increased BMI.

Effects of Drugs and Chemotherapeutic Agents on Dental Implant Osseointegration: Narrative Review

BACKGROUND

Dental implants have been one of the most popular treatments for rehabilitating individuals with single missing teeth or fully edentulous jaws since their introduction. As more implant patients are well-aged and take several medications due to various systemic conditions, clinicians should be mindful of possible drug implications on bone remodeling and osseointegration.

OBJECTIVE

The present study aims to study and review some desirable and some unwelcomed implications of medicine on osseointegration.

METHODS

A broad search for proper relevant studies were conducted in four databases, including Web of Science, Pubmed, Scopus, and Google Scholar.

RESULTS

Some commonly prescribed medicines such as nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, proton pump inhibitors (PPIs), selective serotonin reuptake inhibitors (SSRIs), anticoagulants, metformin, and chemotherapeutic agents may jeopardize osseointegration. On the contrary, some therapeutic agents such as anabolic, anti-catabolic, or dual anabolic and anti-catabolic agents may enhance osseointegration and increase the treatment's success rate.

CONCLUSION

Systemic medications that enhance osseointegration include mineralization promoters and bone resorption inhibitors. On the other hand, medications often given to the elderly with systemic problems might interfere with osseointegration, leading to implant failure. However, to validate the provided research, more human studies with a higher level of evidence are required.

A Traditional Chinese Medicine Plant Extract Prevents Alcohol-Induced Osteopenia

Traditional Chinese medicine (TCM) has been practiced in the treatment of bone diseases and alcoholism. Chronic excessive alcohol use results in alcohol-induced bone diseases, including osteopenia and osteoporosis, which increases fracture risk, deficient bone repair, and osteonecrosis. This preclinical study investigated the therapeutic effects of TCM herbal extracts in animal models of chronic excessive alcohol consumption-induced osteopenia. TCM herbal extracts (Jing extracts) were prepared from nine Chinese herbal medicines, a combinative herbal formula for antifatigue and immune regulation, including Astragalus, Cistanche deserticola, Dioscorea polystachya, Lycium barbarum, Epimedium, Cinnamomum cassia, Syzygium aromaticum, Angelica sinensis, and Curculigo orchioides. In this study, Balb/c male mice were orally administrated alcohol (3.2 g/kg/day) with/without TCM herbal extracts (0.125 g/kg, 0.25 g/kg, or 0.5 g/kg) by gavage. Our results showed that after 50 days of oral administration, TCM herbal extracts prevented alcohol-induced osteopenia demonstrated by μ-CT bone morphological analysis in young adults and middle-aged/old Balb/c male mice. Biochemical analysis demonstrated that chronic alcohol consumption inhibits bone formation and has a neutral impact on bone resorption, suggesting that TCM herbal extracts (Jing extracts) mitigate the alcohol-induced abnormal bone metabolism in middle-aged/old male mice. Protocatechuic acid, a natural phenolic acid in Jing extracts, mitigates in vivo alcohol-induced decline of alkaline phosphatase (ALP) gene expression in the bone marrow of Balb/c male mice and in vitro ALP activity in pre-osteoblast MC3T3-E1 cells. Our study suggests that TCM herbal extracts prevent chronic excessive alcohol consumption-induced osteopenia in male mice, implying that traditional medicinal plants have the therapeutic potential of preventing alcohol-induced bone diseases.

Effect of ethanol consumption during pregnancy and lactation on bone histomorphometry and in vitro osteogenic differentiation of bone marrow mesenchymal stem cells in maternal rats

This study aimed to evaluate the effect of maternal ethanol consumption during gestation and lactation on bone mass and osteogenic differentiation of mesenchymal stem cells of the bone marrow (BMMSCs) in rats. Thirteen adult Wistar rats were used. The rats were mated, and after confirmation of gestation, (day 0) they were distributed in two groups: the control group and the ethanol-treated group. From the ninth day of gestation, the rats of the ethanol and control groups were administered 40% alcoholic solution (4 g ethanol/kg) and distilled water, respectively, daily via gavage until the thirtieth day of lactation. The BMMSCs were extracted from the right femurs and tibiae and cultured using an osteogenic medium for 7, 14, and 21 days. The conversion of MTT to formazan crystals, alkaline phosphatase activity, and percentages of cells per field were analyzed. The number of mineralized nodules per field was examined, and quantification of the gene transcripts for osteopontin, osteocalcin, and BMP-2 was evaluated on day 21 by real-time RT-PCR. Morphometric evaluations of the percentage of trabecular bone and cortical thickness in the left femur and tibia were performed. The means were compared by the Student's t-test, and the differences were considered significant if p < 0.05. The BMMSCs of the rats that consumed ethanol during gestation and lactation, when subjected to osteogenic differentiation in vitro, demonstrated higher conversion of MTT to formazan, higher alkaline phosphatase activity, a higher percentage of cells per field, higher expression of BMP-2, and higher synthesis of mineralized nodules when compared to those of control rat cells. However, there was no significant difference in the percentage of trabecular bone or cortical thickness between both groups. Hence, the consumption of ethanol during pregnancy and lactation did not alter the trabecular and cortical bone tissues of the femur and tibia compared with that of pregnant and lactating control rats that did not consume alcohol, despite BMMSCs showing higher osteogenic differentiation under in vitro conditions.

Neuropathophysiology of coronavirus disease 2019: neuroinflammation and blood brain barrier disruption are critical pathophysiological processes that contribute to the clinical symptoms of SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) is caused by the novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) first discovered in Wuhan, Hubei province, China in December 2019. SARS-CoV-2 has infected several millions of people, resulting in a huge socioeconomic cost and over 2.5 million deaths worldwide. Though the pathogenesis of COVID-19 is not fully understood, data have consistently shown that SARS-CoV-2 mainly affects the respiratory and gastrointestinal tracts. Nevertheless, accumulating evidence has implicated the central nervous system in the pathogenesis of SARS-CoV-2 infection. Unfortunately, however, the mechanisms of SARS-CoV-2 induced impairment of the central nervous system are not completely known. Here, we review the literature on possible neuropathogenic mechanisms of SARS-CoV-2 induced cerebral damage. The results suggest that downregulation of angiotensin converting enzyme 2 (ACE2) with increased activity of the transmembrane protease serine 2 (TMPRSS2) and cathepsin L in SARS-CoV-2 neuroinvasion may result in upregulation of proinflammatory mediators and reactive species that trigger neuroinflammatory response and blood brain barrier disruption. Furthermore, dysregulation of hormone and neurotransmitter signalling may constitute a fundamental mechanism involved in the neuropathogenic sequelae of SARS-CoV-2 infection. The viral RNA or antigenic peptides also activate or interact with molecular signalling pathways mediated by pattern recognition receptors (e.g., toll-like receptors), nuclear factor kappa B, Janus kinase/signal transducer and activator of transcription, complement cascades, and cell suicide molecules. Potential molecular targets and therapeutics of SARS-CoV-2 induced neurologic damage are also discussed.

Alcohol consumption induces murine osteoporosis by downregulation of natural killer T-like cell activity

Introduction

Chronic alcohol consumption (CAC) can induce several deleterious effects on the body, including the promotion of osteoporosis; however, the immunological mechanism underlying alcohol‐induced osteoporosis is still unclear.

Methods

We administered alcohol to mice for 4 weeks as the experimental CAC model and analyzed the bone and immune cells that are located in the vicinity of a bone.

Results

IL‐4 is known to be a suppressive factor for osteoclastogenesis, and we found that natural killer T (NKT)‐like cells, which showed NK1.1‐positive, CD3‐positive, and α‐galactosylceramide‐loaded CD1d tetramer‐negative, produced IL‐4 more effectively than CD4⁺ T and natural killer (NK) cells. The alcohol consumption facilitated a significant decrease of bone mineral density with the upregulation of nuclear factor of activated T cells 1 and receptor activator of NF‐κB ligand expression. Meanwhile, we confirmed that alcohol consumption suppressed the activity of antigen‐presenting cells (APCs) and NKT‐like cells, leading to decreased IL‐4 secretion. Moreover, these harmful effects of alcohol consumption were reduced by simultaneous treatment with a glycolipid antigen OCH.

Conclusions

Our results indicate that the inactivation of innate immune cells, APCs, and NKT‐like cells are likely to be crucial for alcohol‐induced osteoporosis and provide a new therapeutic approach for preventing osteoporosis.

Potential mechanisms linking psychological stress to bone health

Chronic psychological stress affects many body systems, including the skeleton, through various mechanisms. This review aims to provide an overview of the factors mediating the relationship between psychological stress and bone health. These factors can be divided into physiological and behavioural changes induced by psychological stress. The physiological factors involve endocrinological changes, such as increased glucocorticoids, prolactin, leptin and parathyroid hormone levels and reduced gonadal hormones. Low-grade inflammation and hyperactivation of the sympathetic nervous system during psychological stress are also physiological changes detrimental to bone health. The behavioural changes during mental stress, such as altered dietary pattern, cigarette smoking, alcoholism and physical inactivity, also threaten the skeletal system. Psychological stress may be partly responsible for epigenetic regulation of skeletal development. It may also mediate the relationship between socioeconomic status and bone health. However, more direct evidence is required to prove these hypotheses. In conclusion, chronic psychological stress should be recognised as a risk factor of osteoporosis and stress-coping methods should be incorporated as part of the comprehensive osteoporosis-preventing strategy.

Binge-Like Exposure During Adolescence Induces Detrimental Effects in Alveolar Bone that Persist in Adulthood

BACKGROUND

Alcohol (EtOH) intake during adolescence has become an important public health issue. Although the detrimental effects of EtOH intake on the musculoskeletal system are well known, only a few studies have investigated its impact on the stomatognathic system of adolescents. This study aimed to investigate the effect of EtOH binge drinking on the alveolar bone and the long-term consequences after abstinence.

METHODS

Adolescent female Wistar rats (35 days old) were exposed to 4 cycles of EtOH binge drinking (3 g/kg/d; 3 days On-4 days Off) or distilled water (control group). Alveolar bone micromorphology and vertical bone distance were evaluated at 1, 30, and 60 days after that last EtOH intake through X-ray computed microtomography. The mineral:matrix ratio was assessed through Raman spectroscopy.

RESULTS

A decrease in both trabecular thickness and volume ratio, and an increase in trabecular separation were observed at the 1-day evaluation (immediate withdrawal). After 30 and 60 days, the alveolar bone parameters were found similar to control, except for the mineral:matrix ratio in the long-term abstinence.

CONCLUSIONS

EtOH binge drinking during adolescence results in alveolar bone damage that may persist in adulthood, even after abstinence.

G-CSF shifts erythropoiesis from bone marrow into spleen in the setting of systemic inflammation

The anemia of inflammation is related in part to abnormal erythropoiesis in bone marrow. G-CSF regulates granulopoiesis and is increased during systemic inflammation. Here, we have showed that high levels of G-CSF are associated with repression of bone marrow erythropoiesis and expansion of splenic erythropoiesis in Escherichia coli-infected mice and lipopolysaccharide-treated mice. Under lipopolysaccharide-induced systemic inflammatory conditions in mice, G-CSF neutralization with antibody alleviated the blockage of bone marrow erythropoiesis, prevented the enhancement of splenic erythropoiesis, ameliorated splenomegaly, and reduced the brittleness of spleen. We further demonstrated that after lipopolysaccharide treatment, TLR4-knockout mice display low levels of G-CSF, healthy bone marrow erythropoiesis, almost no stress erythropoiesis in the spleen, and normal size and toughness of spleen. In addition, we found HIF-mediated erythropoietin production is essential for splenic erythropoiesis in the setting of G-CSF-induced suppression of bone marrow erythropoiesis. Our findings identify G-CSF as a critical mediator of inflammation-associated erythropoiesis dysfunction in bone marrow and offer insight into the mechanism of G-CSF-induced splenic erythropoiesis. We provide experimentally significant dimension to the biology of G-CSF.

Effects of Chronic Ethanol Consumption and Ovariectomy on the Spontaneous Alveolar Bone Loss in Rats

Postmenopausal estrogen deficiency and ethanol (EtOH) abuse are known risk factors for different diseases including bone tissues. However, little is known about the synergic effects of EtOH abuse and estrogen deficiency on alveolar bone loss in women. The present study evaluated the effects of EtOH chronic exposure and ovariectomy on the alveolar bone loss in female rats. For this, 40 female Wistar rats were randomly divided into 4 groups: control, EtOH exposure, ovariectomy (OVX), and OVX plus EtOH exposure. Initially, half of the animals were ovariectomized at 75 days of age. After that, the groups received distilled water or EtOH 6.5 g/kg/day (20% w/v) for 55 days via gavage. Thereafter, animals were sacrificed and the mandibles were collected, dissected, and separated into hemimandibles. Alveolar bone loss was evaluated by measuring the distance between the cementoenamel junction and the alveolar bone crest through a stereomicroscope in 3 different anatomical regions of the tissue. One-way ANOVA and post hoc Tukey were used to compare groups (p < 0.05). The results showed that the ovariectomy and EtOH exposure per se were able to induce alveolar bone loss, and their association did intensify significantly the effect. Therefore, OVX associated with heavy EtOH exposure increase the spontaneous alveolar bone loss in rats.

A critical assessment of the potential of pharmacological modulation of aldehyde dehydrogenases to treat the diseases of bone loss

Chronic alcoholism (CA) decreases bone mass and increases the risk of hip fracture. Alcohol and its main metabolite, acetaldehyde impairs osteoblastogenesis by increasing oxidative stress. Aldehyde dehydrogenase (ALDH) is the rate-limiting enzyme in clearing acetaldehyde from the body. The clinical relevance of ALDH in skeletal function has been established by the discovery of single nucleotide polymorphism, SNP (rs671) in the ALDH2 gene giving rise to an inactive form of the enzyme (ALDH2*2) that causes increased serum acetaldehyde and osteoporosis in the affected individuals. Subsequent mouse genetics studies have replicated human phenotype in mice and confirmed the non-redundant role of ALDH2 in bone homeostasis. The activity of ALDH2 is amenable to pharmacological modulation. ALDH2 inhibition by disulfiram (DSF) and activation by alda-1 cause reduction and induction of bone formation, respectively. DSF also inhibits peak bone mass accrual in growing rats. On the other hand, DSF showed an anti-osteoclastogenic effect and protected mice from alcohol-induced osteopenia by inhibiting ALDH1a1 in bone marrow monocytes. Besides DSF, there are several classes of ALDH inhibitors with disparate skeletal effects. Alda-1, the ALDH2 activator induced osteoblast differentiation by increasing bone morphogenic protein 2 (BMP2) expression via ALDH2 activation. Alda-1 also restored ovariectomy-induced bone loss. The scope of structure-activity based studies with ALDH2 and the alda-1-like molecule could lead to the discovery of novel osteoanabolic molecules. This review will critically discuss the molecular mechanism of the ethanol and its principal metabolite, acetaldehyde in the context of ALDH2 in bone cells, and skeletal homeostasis.

Joint Reconstituted Signaling of the IL-6 Receptor via Extracellular Vesicles

Interleukin-6 (IL-6) signaling is a crucial regulatory event important for many biological functions, such as inflammation and tissue regeneration. Accordingly, several pathological conditions are associated with dysregulated IL-6 activity, making it an attractive therapeutic target. For instance, blockade of IL-6 or its α-receptor (IL-6R) by monoclonal antibodies has been successfully used to treat rheumatoid arthritis. However, based on different signaling modes, IL-6 function varies between pro- and anti-inflammatory activity, which is critical for therapeutic intervention. So far, three modes of IL-6 signaling have been described, the classic anti-inflammatory signaling, as well as pro-inflammatory trans-signaling, and trans-presentation. The IL-6/IL-6R complex requires an additional β-receptor (gp130), which is expressed on almost all cells of the human body, to induce STAT3 (signal transducer and activator of signal transcription 3) phosphorylation and subsequent transcriptional regulation. In contrast, the IL-6R is expressed on a limited number of cells, including hepatocytes and immune cells. However, the proteolytic release of the IL-6R enables trans-signaling on cells expressing gp130 only. Here, we demonstrate a fourth possibility of IL-6 signaling that we termed joint reconstituted signaling (JRS). We show that IL-6R on extracellular vesicles (EVs) can also be transported to and fused with other cells that lack the IL-6R on their surface. Importantly, JRS via EVs induces delayed STAT3 phosphorylation compared to the well-established trans-signaling mode. EVs isolated from human serum were already shown to carry the IL-6R, and thus this new signaling mode should be considered with regard to signal intervention.

Indian Hedgehog regulates senescence in bone marrow-derived mesenchymal stem cell through modulation of ROS/mTOR/4EBP1, p70S6K1/2 pathway

Premature senescence of bone marrow-derived mesenchymal stem cells (BMSC) remains a major concern for their application clinically. Hedgehog signaling has been reported to regulate aging-associated markers and MSC skewed differentiation. Indian Hedgehog (IHH) is a ligand of Hedgehog intracellular pathway considered as an inducer in chondrogenesis of human BMSC. However, the role of IHH in the aging of BMSC is still unclear. This study explored the role IHH in the senescence of BMSC obtained from human samples and senescent mice. Isolated BMSC were transfected with IHH siRNA or incubated with exogenous IHH protein and the mechanisms of aging and differentiation investigated. Moreover, the interactions between IHH, and mammalian target of rapamycin (mTOR) and reactive oxygen species (ROS) were evaluated using the corresponding inhibitors and antioxidants. BMSC transfected with IHH siRNA showed characteristics of senescence-associated features including increased senescence-associated β-galactosidase activity (SA-β-gal), induction of cell cycle inhibitors (p53/p16), development of senescence-associated secretory phenotype (SASP), activation of ROS and mTOR pathways as well as the promotion of skewed differentiation. Interestingly, BMSC treatment with IHH protein reversed the senescence markers and corrected biased differentiation. Moreover, IHH shortage-induced senescence signs were compromised after mTOR and ROS inhibition. Our findings presented anti-aging activity for IHH in BMSC through down-regulation of ROS/mTOR pathways. This discovery might contribute to increasing the therapeutic, immunomodulatory and regenerative potency of BMSC and introduce a novel remedy in the management of aging-related diseases.

Iron-enriched diet contributes to early onset of osteoporotic phenotype in a mouse model of hereditary hemochromatosis

Osteoporosis is associated with chronic iron overload secondary to hereditary hemochromatosis (HH), but the causative mechanisms are incompletely understood. The main objective of this study was to investigate the role of dietary iron on osteoporosis, using as biological model the Hfe-KO mice, which have a systemic iron overload. We showed that these mice show an increased susceptibility for developing a bone loss phenotype compared to WT mice, which can be exacerbated by an iron rich diet. The dietary iron overload caused an increase in inflammation and iron incorporation within the trabecular bone in both WT and Hfe-KO mice. However, the osteoporotic phenotype was only evident in Hfe-KO mice fed the iron-enriched diet. This appeared to result from an imbalance between bone formation and bone resorption driven by iron toxicity associated to Hfe-KO and confirmed by a decrease in bone microarchitecture parameters (identified by micro-CT) and osteoblast number. These findings were supported by the observed downregulation of bone metabolism markers and upregulation of ferritin heavy polypeptide 1 (Fth1) and transferrin receptor-1 (Tfrc), which are associated with iron toxicity and bone loss phenotype. In WT mice the iron rich diet was not enough to promote a bone loss phenotype, essentially due to the concomitant depression of bone resorption observed in those animals. In conclusion the dietary challenge influences the development of osteoporosis in the HH mice model thus suggesting that the iron content in the diet may influence the osteoporotic phenotype in systemic iron overload conditions.

Regulation of fetal hemoglobin expression during hematopoietic stem cell development and its importance in bone metabolism and osteoporosis

We have shown that an altered tissue redox environment in mice lacking either murine beta Hemoglobin major (Hgbβ_maKO) or minor (Hgbβ_miKO) regulates inflammation. The REDOX environment in marrow stem cell niches also control differentiation pathways. We investigated osteoclastogenesis (OC)/osteoblastogenesis (OB), in bone cultures derived from untreated or FSLE-treated WT, Hgbβ_maKO or Hgbβ_miKO mice. Marrow mesenchymal cells from 10d pre-cultures were incubated on an osteogenic matrix for 21d prior to analysis of inflammatory cytokine release into culture supernatants, and relative OC:OB using (TRAP:BSP, RANKL:OPG) mRNA expression ratios and TRAP or Von Kossa staining. Cells from WT and Hgbβ_maKO mice show decreased IL-1β,TNFα and IL-6 production and enhanced osteoblastogenesis with altered mRNA expression ratios and increased bone nodules (Von Kossa staining) in vitro after in vivo stimulation of mRNA expression of fetal Hgb genes (Hgbε and Hgbβ_mi) by a fetal liver extract (FSLE). Marrow from Hgbβ_miKO showed enhanced cytokine release and preferential enhanced osteoclastogenesis relative to similar cells from WT or Hgbβ_maKO mice, with no increased osteoblastogenesis after mouse treatment with FSLE. Pre-treatment of WT or Hgbβ_maKO, but not Hgbβ_miKO mice, with other molecules (rapamycin; hydroxyurea) which increase expression of fetal Hgb genes also augmented osteoblastogenesis and decreased cytokine production in cells differentiating in vitro. Infusion of rabbit anti- Hgbε or anti- Hgbβ_mi, but not anti-Hgbα or anti- Hgbβ_ma into WT mice from day 13 gestation for 3 weeks led to attenuated osteoblastogenesis in cultured cells. We conclude that increased fetal hemoglobin expression, or use of agents which improve fetal hemoglobin expression, increases osteoblast bone differentiation in association with decreased inflammatory cytokine release.

Cellular and molecular mechanisms of alcohol-induced osteopenia

Alcoholic beverages are widely consumed, resulting in a staggering economic cost in different social and cultural settings. Types of alcohol consumption vary from light occasional to heavy, binge drinking, and chronic alcohol abuse at all ages. In general, heavy alcohol consumption is widely recognized as a major epidemiological risk factor for chronic diseases and is detrimental to many organs and tissues, including bones. Indeed, recent findings demonstrate that alcohol has a dose-dependent toxic effect in promoting imbalanced bone remodeling. This imbalance eventually results in osteopenia, an established risk factor for osteoporosis. Decreased bone mass and strength are major hallmarks of osteopenia, which is predominantly attributed not only to inhibition of bone synthesis but also to increased bone resorption through direct and indirect pathways. In this review, we present knowledge to elucidate the epidemiology, potential pathogenesis, and major molecular mechanisms and cellular effects that underlie alcoholism-induced bone loss in osteopenia. Novel therapeutic targets for correcting alcohol-induced osteopenia are also reviewed, such as modulation of proinflammatory cytokines and Wnt and mTOR signaling and the application of new drugs.

Lifestyle factors are significantly associated with the locomotive syndrome: a cross-sectional study

Background

The Japanese Orthopedic Association first proposed the concept of “locomotive syndrome” in 2007. It refers to circumstances in which elderly people need nursing care services or are at high risk of requiring such services within a short time. Recently, the public health burden of providing nursing care for elderly individuals has increased. Therefore, locomotive syndrome, and the means of preventing it, are a major public health focus in Japan. The purpose of this study was to investigate the relationships of lifestyle factors, such as smoking, alcohol consumption, sleep duration, and dental health, with locomotive syndrome.

Methods

We conducted a cross-sectional study using an internet panel survey. The participants comprised 747 individuals aged 30–90 years. Factors related to demographics (age, sex), general health (number of teeth, presence of periodontal disease), and lifestyle (smoking, alcohol consumption, sleep duration) were assessed. We also used the 25-question Geriatric Locomotive Function Scale to determine whether each participant had locomotive syndrome. Multivariate analysis was conducted using logistic regression to investigate the independent relationships between locomotive syndrome and lifestyle factors after adjusting for sex and age.

Results

A greater proportion of women (17.7%) than men (11.2%) had locomotive syndrome (p < 0.05). Participants aged ≥65 years showed significantly higher percentages (men: 21.4%, women: 75.7%) of locomotive syndrome compared with those aged <65 years (p < 0.05). Logistic regression analysis revealed that older age (≥ 65 years), sex, current smoking status, number of existing teeth, and presence of periodontal disease were associated with locomotive syndrome, whereas sleep duration was not. The frequency of alcohol consumption, except for daily drinking, was also associated with locomotive syndrome.

Conclusion

Our study indicates that lifestyle factors, such as smoking and number of existing teeth, may partly affect the prevalence of locomotive syndrome. Hence, lifestyle modifications, such as improving oral hygiene and promoting cessation of smoking, are important means to reduce the risk of locomotive syndrome and should be promoted by public health staff.

Chronic alcohol abuse in men alters bone mechanical properties by affecting both tissue mechanical properties and microarchitectural parameters

OBJECTIVE OF THE STUDY

Alcohol-induced secondary osteoporosis in men has been characterized by higher fracture prevalence and a modification of bone microarchitecture. Chronic alcohol consumption impairs bone cell activity and results in an increased fragility. A few studies highlighted effects of heavy alcohol consumption on some microarchitectural parameters of trabecular bone. But to date and to our knowledge, micro- and macro-mechanical properties of bone of alcoholic subjects have not been investigated.

PATIENTS

In the present study, mechanical properties and microarchitecture of trabecular bone samples from the iliac crest of alcoholic male patients (n=15) were analyzed and compared to a control group (n=8).

MATERIALS AND METHODS

Nanoindentation tests were performed to determine the tissue's micromechanical properties, micro-computed tomography was used to measure microarchitectural parameters, and numerical simulations provided the apparent mechanical properties of the samples.

RESULTS

Compared to controls, bone tissue from alcoholic patients exhibited an increase of micromechanical properties at tissue scale, a significant decrease of apparent mechanical properties at sample scale, and significant changes in several microarchitectural parameters. In particular, a crucial role of structure model index (SMI) on mechanical properties was identified.

CONCLUSIONS

3D microarchitectural parameters are at least as important as bone volume fraction to predict bone fracture risk in the case of alcoholic patients.

Does Oxidative Stress Induced by Alcohol Consumption Affect Orthodontic Treatment Outcome?

HIGHLIGHTS Ethanol, Periodontal ligament, Extracellular matrix, Orthodontic movement. Alcohol is a legal drug present in several drinks commonly used worldwide (chemically known as ethyl alcohol or ethanol). Alcohol consumption is associated with several disease conditions, ranging from mental disorders to organic alterations. One of the most deleterious effects of ethanol metabolism is related to oxidative stress. This promotes cellular alterations associated with inflammatory processes that eventually lead to cell death or cell cycle arrest, among others. Alcohol intake leads to bone destruction and modifies the expression of interleukins, metalloproteinases and other pro-inflammatory signals involving GSKβ, Rho, and ERK pathways. Orthodontic treatment implicates mechanical forces on teeth. Interestingly, the extra- and intra-cellular responses of periodontal cells to mechanical movement show a suggestive similarity with the effects induced by ethanol metabolism on bone and other cell types. Several clinical traits such as age, presence of systemic diseases or pharmacological treatments, are taken into account when planning orthodontic treatments. However, little is known about the potential role of the oxidative conditions induced by ethanol intake as a possible setback for orthodontic treatment in adults.

Partial Protection by Dietary Antioxidants Against Ethanol-Induced Osteopenia and Changes in Bone Morphology in Female Mice

BACKGROUND

Chronic alcohol consumption leads to increased fracture risk and an elevated risk of osteoporosis by decreasing bone accrual through increasing osteoclast activity and decreasing osteoblast activity. We have shown that this mechanism involves the generation of reactive oxygen species (ROS) produced by NADPH oxidases. It was hypothesized that different dietary antioxidants, N-acetyl cysteine (NAC; 1.2 mg/kg/d), and α-tocopherol (Vit.E; 60 mg/kg/d) would be able to attenuate the NADPH oxidase-mediated ROS effects on bone due to chronic alcohol intake.

METHODS

To study the effects of these antioxidants, female mice received a Lieber-DeCarli liquid diet containing ethanol (EtOH) with or without additional antioxidant for 8 weeks.

RESULTS

Tibias displayed decreased cortical bone mineral density in both the EtOH and EtOH + antioxidant groups compared to pair-fed (PF) and PF + antioxidant groups (p < 0.05). However, there was significant protection from trabecular bone loss in mice fed either antioxidant (p < 0.05). Microcomputed tomography analysis demonstrated a significant decrease in bone volume (bone volume/tissue volume) and trabecular number (p < 0.05), along with a significant increase in trabecular separation in the EtOH compared to PF (p < 0.05). In contrast, the EtOH + NAC and EtOH + Vit.E did not statistically differ from their respective PF controls. Ex vivo histologic sections of tibias were stained for nitrotyrosine, an indicator of intracellular damage by ROS, and tibias from mice fed EtOH exhibited significantly more staining than PF controls. EtOH treatment significantly increased the number of marrow adipocytes per mm as well as mRNA expression of aP2, an adipocyte marker in bone. Only NAC was able to reduce the number of marrow adipocytes to PF levels. EtOH-fed mice exhibited reduced bone length (p < 0.05) and had a reduced number of proliferating chondrocytes within the growth plate. NAC and Vit.E prevented this (p < 0.05).

CONCLUSIONS

These data show that alcohol's pathological effects on bone extend beyond decreasing bone mass and suggest a partial protective effect of the dietary antioxidants NAC and Vit.E at these doses with regard to alcohol effects on bone turnover and bone morphology.

Interleukin-16 rs11556218 is associated with a risk of osteoporosis in Chinese postmenopausal women

BACKGROUND

Interleukins (ILs), a multifunctional cytokine, play a fundamental role in inflammatory diseases, as well as in the development of osteoporosis. However, there are no data about the role of IL-16 polymorphism in development of osteoporosis.

PATIENTS AND METHODS

In this study, we investigated the association between the IL-16 rs11556218 T/G and rs4072122 C/T polymorphisms respectively, and the risk of osteoporosis among 230 patients with osteoporosis and 230 healthy controls. Serum IL-16 level and its correlation with the IL-16 rs11556218 T/G genotypes were analyzed.

RESULTS

Significant differences of genotype distribution were observed between osteoporosis cases and controls at the IL-16 rs11556218 T/G genotypes. Compared with the IL-16 rs11556218 T/G homozygote TT, the heterozygous TG genotype was associated with significantly increased risk for osteoporosis (OR=2.29, 95% CI=(1.15-3.82), p=0.026); the GG genotype was associated with increased risk for osteoporosis (OR=1.84, 95% CI=1.48-3.97, p=0.015). TG and GG combined variants that were associated with increased risk for osteoporosis compared with the TT genotype (OR=1.92, 95% CI=1.43-4.86, p=0.023). Moreover, in patients with osteoporosis, there was a correlation between the serum IL-16 and rs11556218 T/G genotype. However, the genotype and allele frequencies of IL-16 rs4072122 C/T polymorphisms in osteoporosis patients were not significantly different from controls.

CONCLUSION

IL-16 rs11556218 T/G genotype was associated with increased risk for development of osteoporosis in Chinese postmenopausal women.

Diagnosis and Management of Cirrhosis-Related Osteoporosis

Management of cirrhosis complications has greatly improved, increasing survival and quality of life of the patients. Despite that, some of these complications are still overlooked and scarcely treated, particularly those that are not related to the liver. This is the case of osteoporosis, the only cirrhosis complication that is not solved after liver transplantation, because bone loss often increases after immunosuppressant therapy. In this review, the definitions of bone conditions in cirrhotic patients are analyzed, focusing on the more common ones and on those that have the largest impact on this population. Risk factors, physiopathology, diagnosis, screening strategies, and treatment of osteoporosis in cirrhotic patients are discussed, presenting the more striking data on this issue. Therapies used for particular conditions, such as primary biliary cirrhosis and liver transplantation, are also presented.

Bone health and vitamin D status in alcoholic liver disease

Alcohol consumption is harmful to many organs and tissues, including bones, and it leads to osteoporosis. Hepatic osteodystrophy is abnormal bone metabolism that has been defined in patients with chronic liver disease (CLD), including osteopenia, osteoporosis, and osteomalacia. Decreased bone density in patients with CLD results from decreased bone formation or increased bone resorption. The prevalence of osteopenia in alcoholic liver disease (ALD) patients is between 34 % and 48 %, and the prevalence of osteoporosis is between 11 % and 36 %. Cirrhosis is also a risk factor for osteoporosis. The liver has an important role in vitamin D metabolism. Ninety percent of patients with alcoholic liver cirrhosis have vitamin D inadequacy (<80 nmol/L). The lowest serum vitamin D levels were observed in patients with Child-Pugh class C. Bone densitometry is used for the definitive diagnosis of osteoporosis in ALD. There are no specific controlled clinical studies on the treatment of osteoporosis in patients with ALD. Alcohol cessation and abstinence are principal for the prevention and treatment of osteoporosis in ALD patients, and the progression of osteopenia can be stopped in this way. Calcium and vitamin D supplementation is recommended, and associated nutritional deficiencies should also be corrected. The treatment recommendations of osteoporosis in CLD tend to be extended to ALD. Bisphosphonates have been proven to be effective in increasing bone mineral density (BMD) in chronic cholestatic disease and post-transplant patients, and they can be used in ALD patients. Randomized studies assessing the management of CLD-associated osteoporosis and the development of new drugs for osteoporosis may change the future. Here, we will discuss bone quality, vitamin D status, mechanism of bone effects, and diagnosis and treatment of osteoporosis in ALD.

Clinical effects of tocilizumab on cytokines and immunological factors in patients with rheumatoid arthritis

Interleukin (IL)-6 is one of the crucial proinflammatory cytokines. The dysregulation of IL-6 plays a pivotal role in rheumatoid arthritis (RA) and is involved in several of the common clinical manifestations associated with active RA. Recent therapies targeting IL-6 and tumor necrosis factor (TNF) have resulted in clinical improvements in signs and symptoms, disability and quality of life in patients with early and long-standing RA. Because it has been demonstrated that cytokines and inflammatory/immunological factors appear to be important and sensitive mediators in RA patients treated with tocilizumab and with anti-TNF biologics, it is important to investigate whether tocilizumab administration has any effect(s) on the profiles of cytokines and inflammatory/immunological factors and whether these changes correlate with the clinical improvement in RA disease activity. In this review, we discuss the effects on cytokine regulation and the differentiation of immune cells, especially T cells, after tocilizumab therapy in patients with RA.

Alcohol: A Simple Nutrient with Complex Actions on Bone in the Adult Skeleton

BACKGROUND

Alcohol is an important nonessential component of diet, but the overall impact of drinking on bone health, especially at moderate levels, is not well understood. Bone health is important because fractures greatly reduce quality of life and are a major cause of morbidity and mortality in the elderly. Regular alcohol consumption is most common following skeletal maturity, emphasizing the importance of understanding the skeletal consequences of drinking in adults.

METHODS

This review focuses on describing the complex effects of alcohol on the adult skeleton. Studies assessing the effects of alcohol on bone in adult humans as well as skeletally mature animal models published since the year 2000 are emphasized.

RESULTS

Light to moderate alcohol consumption is generally reported to be beneficial, resulting in higher bone mineral density (BMD) and reduced age-related bone loss, whereas heavy alcohol consumption is generally associated with decreased BMD, impaired bone quality, and increased fracture risk. Bone remodeling is the principal mechanism for maintaining a healthy skeleton in adults and dysfunction in bone remodeling can lead to bone loss and/or decreased bone quality. Light to moderate alcohol may exert beneficial effects in older individuals by slowing the rate of bone remodeling, but the impact of light to moderate alcohol on bone remodeling in younger individuals is less certain. The specific effects of alcohol on bone remodeling in heavy drinkers are even less certain because the effects are often obscured by unhealthy lifestyle choices, alcohol-associated disease, and altered endocrine signaling.

CONCLUSIONS

Although there have been advances in understanding the complex actions of alcohol on bone, much remains to be determined. Limited evidence implicates age, skeletal site evaluated, duration, and pattern of drinking as important variables. Few studies systematically evaluating the impact of these factors have been conducted and should be made a priority for future research. In addition, studies performed in skeletally mature animals have potential to reveal mechanistic insights into the precise actions of alcohol and associated comorbidity factors on bone remodeling.

Lifestyle and osteoporosis

Osteoporosis is associated with a number of lifestyle factors, including nutritional factors such as intake of calcium, protein, dairy food, fruits and vegetables and vitamin D status, and behavioural factors such as physical activity, smoking and alcohol consumption. Ensuring adequate calcium intake and vitamin D status and having regular weight-bearing physical activity throughout life are important for bone health and the prevention of osteoporosis and related fractures. Studies have shown that smoking and excessive alcohol intake have adverse effects on bone health and increase the risk of fracture. There is evidence suggesting that adequate protein intake and higher intake of fruits and vegetables are beneficial to bone health.

Characterization of bone marrow-derived mesenchymal stem cells in aging

Adult mesenchymal stem cells are a resource for autologous and allogeneic cell therapies for immune-modulation and regenerative medicine. However, patients most in need of such therapies are often of advanced age. Therefore, the effects of the aged milieu on these cells and their intrinsic aging in vivo are important considerations. Furthermore, these cells may require expansion in vitro before use as well as for future research. Their aging in vitro is thus also an important consideration. Here, we focus on bone marrow mesenchymal stem cells (BMSCs), which are unique compared to other stem cells due to their support of hematopoietic cells in addition to contributing to bone formation. BMSCs may be sensitive to age-related diseases and could perpetuate degenerative diseases in which bone remodeling is a contributory factor. Here, we review (1) the characterization of BMSCs, (2) the characterization of in vivo-aged BMSCs, (3) the characterization of in vitro-aged BMSCs, and (4) potential approaches to optimize the performance of aged BMSCs. This article is part of a Special Issue entitled "Stem Cells and Bone".

The effects of binge-pattern alcohol consumption on orthodontic tooth movement

OBJECTIVE:

This study aimed to assess tissue changes during orthodontic movement after binge-pattern ethanol 20% exposure.

METHODS:

Male Wistar rats (n = 54) were divided into two groups. The control group (CG) received 0.9% saline solution, while the experimental group (EG) received 20% ethanol in 0.9% saline solution (3 g/kg/day). On the 30^th day, a force of 25 cN was applied with a nickel-titanium closed coil spring to move the maxillary right first molar mesially. The groups were further divided into three subgroups (2, 14 and 28 days). Tartrate-resistant acid phosphatase and picrosirius were used to assess bone resorption and neoformation, respectively. Data were compared by two-way ANOVA, Tukey's HSD, Games-Howell and chi-square test. Significance level was set at 5%.

RESULTS:

There was a decrease in the number of osteoclasts in EG at day 28. The percentage of collagen showed no interaction between group and time.

CONCLUSION:

Binge-pattern 20% ethanol promoted less bone resorption at the end of tooth movement, thereby suggesting delay in tooth movement.

Endothelial interleukin-6 defines the tumorigenic potential of primary human cancer stem cells

Head and neck squamous cell carcinomas (HNSCC) contain a small subpopulation of stem cells endowed with unique capacity to generate tumors. These cancer stem cells (CSC) are localized in perivascular niches and rely on crosstalk with endothelial cells for survival and self-renewal, but the mechanisms involved are unknown. Here, we report that stromal interleukin (IL)-6 defines the tumorigenic capacity of CSC sorted from primary human HNSCC and transplanted into mice. In search for the cellular source of Interleukin-6 (IL-6), we observed a direct correlation between IL-6 levels in tumor-associated endothelial cells and the tumorigenicity of CSC. In vitro, endothelial cell-IL-6 enhanced orosphere formation, p-STAT3 activation, survival, and self-renewal of human CSC. Notably, a humanized anti-IL-6R antibody (tocilizumab) inhibited primary human CSC-mediated tumor initiation. Collectively, these data demonstrate that endothelial cell-secreted IL-6 defines the tumorigenic potential of CSC, and suggest that HNSCC patients might benefit from therapeutic inhibition of IL-6/IL-6R signaling.

Alcoholism: A systemic proinflammatory condition

Excessive ethanol consumption affects virtually any organ, both by indirect and direct mechanisms. Considerable research in the last two decades has widened the knowledge about the paramount importance of proinflammatory cytokines and oxidative damage in the pathogenesis of many of the systemic manifestations of alcoholism. These cytokines derive primarily from activated Kupffer cells exposed to Gram-negative intestinal bacteria, which reach the liver in supra-physiological amounts due to ethanol-mediated increased gut permeability. Reactive oxygen species (ROS) that enhance the inflammatory response are generated both by activation of Kupffer cells and by the direct metabolic effects of ethanol. The effects of this increased cytokine secretion and ROS generation lie far beyond liver damage. In addition to the classic consequences of endotoxemia associated with liver cirrhosis that were described several decades ago, important research in the last ten years has shown that cytokines may also induce damage in remote organs such as brain, bone, muscle, heart, lung, gonads, peripheral nerve, and pancreas. These effects are even seen in alcoholics without significant liver disease. Therefore, alcoholism can be viewed as an inflammatory condition, a concept which opens the possibility of using new therapeutic weapons to treat some of the complications of this devastating and frequent disease. In this review we examine some of the most outstanding consequences of the altered cytokine regulation that occurs in alcoholics in organs other than the liver.

High-throughput screening of mouse gene knockouts identifies established and novel skeletal phenotypes

Screening gene function in vivo is a powerful approach to discover novel drug targets. We present high-throughput screening (HTS) data for 3 762 distinct global gene knockout (KO) mouse lines with viable adult homozygous mice generated using either gene-trap or homologous recombination technologies. Bone mass was determined from DEXA scans of male and female mice at 14 weeks of age and by microCT analyses of bones from male mice at 16 weeks of age. Wild-type (WT) cagemates/littermates were examined for each gene KO. Lethality was observed in an additional 850 KO lines. Since primary HTS are susceptible to false positive findings, additional cohorts of mice from KO lines with intriguing HTS bone data were examined. Aging, ovariectomy, histomorphometry and bone strength studies were performed and possible non-skeletal phenotypes were explored. Together, these screens identified multiple genes affecting bone mass: 23 previously reported genes (Calcr, Cebpb, Crtap, Dcstamp, Dkk1, Duoxa2, Enpp1, Fgf23, Kiss1/Kiss1r, Kl (Klotho), Lrp5, Mstn, Neo1, Npr2, Ostm1, Postn, Sfrp4, Slc30a5, Slc39a13, Sost, Sumf1, Src, Wnt10b), five novel genes extensively characterized (Cldn18, Fam20c, Lrrk1, Sgpl1, Wnt16), five novel genes with preliminary characterization (Agpat2, Rassf5, Slc10a7, Slc26a7, Slc30a10) and three novel undisclosed genes coding for potential osteoporosis drug targets.

Molecular stress-inducing compounds increase osteoclast formation in a heat shock factor 1 protein-dependent manner

Many anticancer therapeutic agents cause bone loss, which increases the risk of fractures that severely reduce quality of life. Thus, in drug development, it is critical to identify and understand such effects. Anticancer therapeutic and HSP90 inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) causes bone loss by increasing osteoclast formation, but the mechanism underlying this is not understood. 17-AAG activates heat shock factor 1 (Hsf1), the master transcriptional regulator of heat shock/cell stress responses, which may be involved in this negative action of 17-AAG upon bone. Using mouse bone marrow and RAW264.7 osteoclast differentiation models we found that HSP90 inhibitors that induced a heat shock response also enhanced osteoclast formation, whereas HSP90 inhibitors that did not (including coumermycin A1 and novobiocin) did not affect osteoclast formation. Pharmacological inhibition or shRNAmir knockdown of Hsf1 in RAW264.7 cells as well as the use of Hsf1 null mouse bone marrow cells demonstrated that 17-AAG-enhanced osteoclast formation was Hsf1-dependent. Moreover, ectopic overexpression of Hsf1 enhanced 17-AAG effects upon osteoclast formation. Consistent with these findings, protein levels of the essential osteoclast transcription factor microphthalmia-associated transcription factor were increased by 17-AAG in an Hsf1-dependent manner. In addition to HSP90 inhibitors, we also identified that other agents that induced cellular stress, such as ethanol, doxorubicin, and methotrexate, also directly increased osteoclast formation, potentially in an Hsf1-dependent manner. These results, therefore, indicate that cellular stress can enhance osteoclast differentiation via Hsf1-dependent mechanisms and may significantly contribute to pathological and therapeutic related bone loss.

Alcohol and bone

Alcohol is widely consumed across the world in different cultural and social settings. Types of alcohol consumption differ between (a) light, only occasional consumption, (b) heavy chronic alcohol consumption, and (c) binge drinking as seen as a new pattern of alcohol consumption among teenagers and young adults. Heavy alcohol consumption is detrimental to many organs and tissues, including bones. Osteoporosis is regularly mentioned as a secondary consequence of alcoholism, and chronic alcohol abuse is established as an independent risk factor for osteoporosis. The review will present the different mechanisms and effects of alcohol intake on bone mass, bone metabolism, and bone strength, including alcoholism-related "life-style factors" such as malnutrition, lack of exercise, and hormonal changes as additional causative factors, which also contribute to the development of osteoporosis due to alcohol abuse.

Cytoprotective effect of American ginseng in a rat ethanol gastric ulcer model

Panax quinquefolium L. (American Ginseng, AG) is one of the most popular herbal medicines in the World. We aimed to investigate whether chronic (28-day) supplementation with AG could protect against ethanol-induced ulcer in gastric tissue. Furthermore, we investigated the possible molecular mechanisms leading to AG-mediated gastric mucosal protection. We randomized 32 male Wistar rats into four groups for treatment (n = 8 per group): supplementation with water (vehicle) and low-dose (AG-1X), medium-dose (AG-2X) and high-dose (AG-5X) AG at 0, 250, 500, and 1250 mg/kg, respectively. In the first experiment, animals were fed vehicle or AG treatments for 4 weeks. At day 29, 75% ethanol was given orally to each animal at 10 mL/kg to induce gastric ulceration for 2 h. In a second experiment, animals were pretreated orally with each treatment for 1 hr before a single oral administration of ethanol (70%, 10 mL/kg). Trend analysis revealed that AG treatments inhibited ethanol-induced gastric mucosal damage. AG supplementation dose-dependently decreased the pro-inflammatory levels of interleukin 1β and cyclooxygenase 2 and the expression of pro-apoptotic proteins tBid, cytochrome C, and caspases-9 and -3 and increased the levels of anti-apoptotic proteins Bcl-2, Bcl-xL and p-Bad. AG could have pharmacological potential for treating gastric ulcer.

DNA damage drives accelerated bone aging via an NF-κB-dependent mechanism

Advanced age is one of the most important risk factors for osteoporosis. Accumulation of oxidative DNA damage has been proposed to contribute to age-related deregulation of osteoblastic and osteoclastic cells. Excision repair cross complementary group 1-xeroderma pigmentosum group F (ERCC1-XPF) is an evolutionarily conserved structure-specific endonuclease that is required for multiple DNA repair pathways. Inherited mutations affecting expression of ERCC1-XPF cause a severe progeroid syndrome in humans, including early onset of osteopenia and osteoporosis, or anomalies in skeletal development. Herein, we used progeroid ERCC1-XPF-deficient mice, including Ercc1-null (Ercc1(-/-)) and hypomorphic (Ercc1(-/Δ)) mice, to investigate the mechanism by which DNA damage leads to accelerated bone aging. Compared to their wild-type littermates, both Ercc1(-/-) and Ercc1(-/Δ) mice display severe, progressive osteoporosis caused by reduced bone formation and enhanced osteoclastogenesis. ERCC1 deficiency leads to atrophy of osteoblastic progenitors in the bone marrow stromal cell (BMSC) population. There is increased cellular senescence of BMSCs and osteoblastic cells, as characterized by reduced proliferation, accumulation of DNA damage, and a senescence-associated secretory phenotype (SASP). This leads to enhanced secretion of inflammatory cytokines known to drive osteoclastogenesis, such as interleukin-6 (IL-6), tumor necrosis factor α (TNFα), and receptor activator of NF-κB ligand (RANKL), and thereby induces an inflammatory bone microenvironment favoring osteoclastogenesis. Furthermore, we found that the transcription factor NF-κB is activated in osteoblastic and osteoclastic cells of the Ercc1 mutant mice. Importantly, we demonstrated that haploinsufficiency of the p65 NF-κB subunit partially rescued the osteoporosis phenotype of Ercc1(-/Δ) mice. Finally, pharmacological inhibition of the NF-κB signaling via an I-κB kinase (IKK) inhibitor reversed cellular senescence and SASP in Ercc1(-/Δ) BMSCs. These results demonstrate that DNA damage drives osteoporosis through an NF-κB-dependent mechanism. Therefore, the NF-κB pathway represents a novel therapeutic target to treat aging-related bone disease.

Curcumin inhibits inflammatory response and bone loss during experimental periodontitis in rats

OBJECTIVE

Curcumin, an active ingredient of turmeric, is proved to be a potential candidate of controlling inflammation and bone resorption, but few reports are on the periodontitis. The purpose of this study was to evaluate whether the intra-gastric administration of curcumin could inhibit the inflammation and alveolar bone resorption in rats following ligature-induced experimental periodontitis.

MATERIALS AND METHOD

Male Wistar rats were randomly divided into three groups: no ligature placement and administration of vehicle, ligature placement and administration of vehicle, ligature placement and administration of curcumin. After the animals were sacrificed, their mandibles were collected for morphological, histological and immunohistochemical analysis; their gingival tissues were collected for cytokine measurements.

RESULTS

Bone resorption was significantly higher in the experimental periodontitis animals treated with vehicle compared with the curcumin-treated group or the control group. Furthermore, receptor activator of nuclear factor-κB ligand (RANKL), receptor activator of nuclear factor-κB (RANK), osteoprotegerin (OPG), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) expression levels were higher in the experimental periodontitis animals treated with vehicle compared with the curcumin treated group or the control group. CONCLUSIONS. Curcumin may decrease alveolar bone loss in the experimental periodontitis rats via suppressing the expression of RANKL/RANK/OPG and its anti-inflammatory properties.

Serum sclerostin in alcoholics: a pilot study

AIMS

Sclerostin is an endogenous inhibitor of the Wnt/β-catenin pathway secreted by osteocytes, which inhibits osteoblast function, differentiation and survival. As a consequence, sclerostin tends to decrease bone mass. Alcoholics frequently present osteoporosis, mainly due to decreased bone synthesis. The behaviour of sclerostin in these patients is unknown. The aim of this work was to analyse the relationship between serum sclerostin levels and bone mineral density (BMD), ethanol consumption, nutritional status, liver function derangement and biomarkers of bone homeostasis in alcoholic patients.

METHODS

We included 31 alcoholic patients, of whom 11 were infected with Hepatitis C virus (HCV) and 7 age and sex-matched controls. All underwent densitometry, and serum sclerostin, osteocalcin, collagen telopeptide, parathyroid hormone (PTH), vitamin D, cortisol and testosterone were determined.

RESULTS

Sclerostin levels were significantly higher in patients (30.95 ± 18.91 pmol/l) than controls (t = 4.4; P < 0.001), especially in non-HCV patients; they showed an inverse correlation with osteocalcin, prothrombin activity and serum albumin, and a direct correlation with bilirubin and telopeptide, but not with BMD, nutritional status or ethanol intake.

CONCLUSIONS

Serum sclerostin was raised in alcoholic patients, and it correlated with decreased markers of bone synthesis and increased markers of bone breakdown. The elevation in sclerostin levels was clearly related with liver function, but not with ethanol intake, nutritional status or concomitant HCV infection.

Vitamin D supplementation protects against bone loss associated with chronic alcohol administration in female mice

Chronic alcohol abuse results in decreased bone mineral density (BMD), which can lead to increased fracture risk. In contrast, low levels of alcohol have been associated with increased BMD in epidemiological studies. Alcohol's toxic skeletal effects have been suggested to involve impaired vitamin D/calcium homeostasis. Therefore, dietary vitamin D supplementation may be beneficial in reducing bone loss associated with chronic alcohol consumption. Six-week-old female C57BL/6J mice were pair-fed ethanol (EtOH)-containing liquid diets (10 or 36% total calories) for 78 days. EtOH exposure at 10% calories had no effects on any measured bone or serum parameter. EtOH consumption at 36% of calories reduced BMD and bone strength (P<0.05), decreased osteoblastogenesis, increased osteoclastogenesis, suppressed 1,25-hydroxyvitamin D3 [1,25(OH)2D3] serum concentrations (P<0.05), and increased apoptosis in bone cells compared with pair-fed controls. In a second study, female mice were pair-fed 30% EtOH diets with or without dietary supplementation with vitamin D3 (cholecalciferol; VitD) for 40 days. VitD supplementation in the EtOH diet protected against cortical bone loss, normalized alcohol-induced hypocalcaemia, and suppressed EtOH-induced expression of receptor of nuclear factor-κB ligand mRNA in bone. In vitro, pretreatment of 1,25(OH)2D3 in osteoblastic cells inhibited EtOH-induced apoptosis. In EtOH/VitD mice circulating 1,25(OH)2D3 was lower compared with mice receiving EtOH alone (P<0.05), suggesting increased sensitivity to feedback control of VitD metabolism in the kidney. These findings suggest dietary VitD supplementation may prevent skeletal toxicity in chronic drinkers by normalizing calcium homeostasis, preventing apoptosis, and suppressing EtOH-induced increases in bone resorption.

The role of serum cytokines in the pathogenesis of hepatic osteodystrophy in male cirrhotic patients

Objective. In this study, we aimed to investigate the possible role of serum cytokines in the development of hepatic osteodystrophy. Matherial and Methods. 44 consecutive male cirrhotic patients (17 alcoholic, 20 hepatitis B, 7 hepatitis C), 15 age- and sex-matched chronic alcoholics without liver disease, and 17 age- and sex-matched healthy controls were included in the study during one year period. Bone mineral density was measured by dual X-ray absorptiometry in the lumbar vertebrate and femoral neck. Serum interleukin levels were measured by ELISA method. Results. Although osteopenia frequency between our cirrhotic patients was 20%, there was no difference in T-scores among the controls and other groups. Serum interleukin-1, interleukin-8, and tumor necrosis factor-alpha levels were not different between all groups. Serum interleukin-2 and interleukin-6 levels were higher in the cirrhotics than controls (P < 0.001). However, there were no significant difference between osteopenic and nonosteopenic cirrhotics. Conclusion. According to the results of the study in this small population of 44 male cirrhotic patients, frequency of hepatic osteopenia is small and serum interleukins 1, 2, 6, 8, and tumor necrosis factor-alpha may not play a role in the pathogenesis of hepatic osteodystrophy. Further studies in which large number of patients involved are necessary in this field.