Alcohol consumption inhibits osteoblastic cell proliferation and activity in vivo

Six months of voluntary alcohol consumption in male cynomolgus macaques reduces intracortical bone porosity without altering mineralization or mechanical properties

Chronic heavy alcohol consumption is a risk factor for low trauma bone fracture. Using a non-human primate model of voluntary alcohol consumption, we investigated the effects of 6 months of ethanol intake on cortical bone in cynomolgus macaques (Macaca fascicularis). Young adult (6.4 ± 0.1 years old, mean ± SE) male cynomolgus macaques (n = 17) were subjected to a 4-month graded ethanol induction period, followed by voluntary self-administration of water or ethanol (4 % w/v) for 22 h/d, 7 d/wk. for 6 months. Control animals (n = 6) consumed an isocaloric maltose-dextrin solution. Tibial response was evaluated using densitometry, microcomputed tomography, histomorphometry, biomechanical testing, and Raman spectroscopy. Global bone response was evaluated using biochemical markers of bone turnover. Monkeys in the ethanol group consumed an average of 2.3 ± 0.2 g/kg/d ethanol resulting in a blood ethanol concentration of 90 ± 12 mg/dl in longitudinal samples taken 7 h after the daily session began. Ethanol consumption had no effect on tibia length, mass, density, mechanical properties, or mineralization (p > 0.642). However, compared to controls, ethanol intake resulted in a dose-dependent reduction in intracortical bone porosity (Spearman rank correlation = -0.770; p < 0.0001) and compared to baseline, a strong tendency (p = 0.058) for lower plasma CTX, a biochemical marker of global bone resorption. These findings are important because suppressed cortical bone remodeling can result in a decrease in bone quality. In conclusion, intracortical bone porosity was reduced to subnormal values 6 months following initiation of voluntary ethanol consumption but other measures of tibia architecture, mineralization, or mechanics were not altered.

Deleterious effect of chronic high-dose ethanol intake on biomechanical bone properties and periodontal status

To evaluate the effect of high-graduation chronic ethanol (EtOH) intake on bone and periodontal tissues of rats. Male Wistar rats (250 g) were divided into two groups of n = 12 each one. EtOH (5 ml of 3 g/kg) was administered to the experimental group by gastric gavage twice a day for 20 days and the control group received water under the same conditions. The rats were euthanized and used to perform biochemical determination in plasma and gingival tissue, and histological and biomechanical studies in the femur and mandibular tissues. Alcohol increased both TNFα (p < 0.01) and PGE2 (p < 0.05) in plasma and gingiva (p < 0.05) as compared to controls. In addition, EtOH increased the alveolar bone loss as evidenced by the increased distance between the cement enamel junction and the alveolar crest (p < 0.01), the lower % of interradicular bone expressed as bone area/total area (B.Ar/T.Ar, p < 0.05) and the larger periodontal space (p < 0.05), as compared to controls. Likewise, the mandibular microtomographic analysis in alcoholized rats revealed a lower % of interradicular bone volume/total volume (BV/TV, p < 0.05), greater trabecular separation (p < 0.05) and greater % trabecular porosity (p < 0.05) than controls. No biomechanical alteration was observed in lower jaws, while the femur of alcoholized rats presented a decrease in the structural bone properties (p < 0.001), as a systemic consequence of deterioration of the diaphyseal architecture (p < 0.01) without changes in material properties. The consumption of high doses of alcohol produces deleterious effects on periodontal tissues that could be due not only to local but also systemic effects.

Episodic alcohol exposure attenuates mesenchymal stem cell chondrogenic differentiation during bone fracture callus formation

BACKGROUND

During bone fracture repair, mesenchymal stem cells (MSC) differentiate into chondrocytes and osteoblasts to form a fracture callus. Our laboratory previously reported that alcohol-exposed rodents with a surgically created tibia fracture display deficient fracture callus formation and diminished signs of endochondral ossification characterized by the absence of chondrocytes and mature hypertrophic chondrocytes, suggesting that alcohol may inhibit MSC differentiation. These findings led to our hypothesis that alcohol exposure inhibits mesenchymal stem cell chondrogenic differentiation within the developing fracture callus.

METHODS

In the present study, we utilized a lineage-tracing approach to determine which stage(s) of chondrogenic differentiation are affected by alcohol exposure. We utilized lineage-specific reporter mice to determine the effects of alcohol on MSC and early and late chondrogenic cell frequencies within the fracture callus. In addition, serially sectioned slides were stained immunofluorescently and immunohistochemically and quantified to determine the effect of alcohol on cell proliferation and apoptosis, respectively, within the fracture callus of alcohol-administered rodents.

RESULTS

Alcohol-administered rodents had a reduced fracture callus area at 4, 6, and 9 days postfracture. Alcohol had no effect on apoptosis in the fracture callus at any of the examined timepoints. Alcohol-administered rodents had significantly fewer proliferative cells in the fracture callus at 9 days postfracture, but no effect on cell proliferation was observed at earlier fracture callus timepoints. Alcohol-administered rodents had reduced Collagen2a1- and Collagen10a1-expressing cells in the developing fracture callus, suggesting that alcohol inhibits both early chondrogenic differentiation and later chondrocyte maturation during fracture callus development.

CONCLUSION

The data suggest that alcohol could affect normal fracture healing through the mitigation of MSC chondrogenic differentiation at the callus site.

Phenotype and synthesis activity of joint chondrocytes extracted from newborn rats with prenatal ethanol exposure

Thirteen female Wistar rats were divided into two groups: one treated with ethanol and the other of untreated. Four newborns from each mother were selected and weighed, measured, and evaluated for physical characteristics. From these neonates, chondrocytes were extracted from the articular cartilages of the femur and tibia, and cultivated in a chondrogenic medium at 37^oC and 5% CO₂. At 7, 14, and 21 days of cultivation, alkaline phosphatase activity tests, MTT conversion to formazan, and percentage area covered by cells per field were performed. At 21 days, the percentage of PAS⁺ areas in 3D cultures was performed, as well as the evaluation of gene transcript expression for aggrecan, SOX-9, collagen type II, collagen X, Runx-2, and VEGF by real-time RT-PCR. The means were compared by Student's t-test. The weight of the ethanol group neonates was significantly lower than that of the controls. Chondrocyte cultures from the ethanol group showed significantly higher AP activity, MTT conversion, and cell percentage. There was higher expression of collagen type II and lower expression of SOX-9 in the ethanol group. There was no difference in the percentage of PAS⁺ areas in pellets and in expression of aggrecan, collagen X, Runx-2, or VEGF between groups. In conclusion, prenatal exposure to ethanol alters the phenotype and activity of offspring chondrocytes, which may be mechanisms by which endochondral bone formation is compromised by maternal ethanol consumption.

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.

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.

Chronic consumption of alcohol increases alveolar bone loss

This study evaluated the effects of the chronic consumption of different concentrations of alcohol on the experimental periodontitis (EP). 160 rats were divided into 4 groups: (EP-NT) rats with EP and no alcohol exposure; (EP-A14) rats with EP exposed to 14% alcohol; (EP-A25) rats with EP exposed to 25% alcohol; (EP-A36) rats with EP exposed to 36% alcohol. The animals from the EP-A14, EP-A25 and EP-A36 groups were subjected to different concentrations of alcohol 30 days before EP induction. The histological characteristics, percentage of bone in the furcation (PBF) and bone metabolism in the furcation region were evaluated. The PBF and tartrate-resistant acid phosphatase (TRAP) data were subjected to statistical analysis. The EP-A14, EP-A25 and EP-A36 groups had lower PBFs compared with the EP-NT group. A more severe inflammatory process and a greater number of TRAP+ cells were also observed. In the EP-A14, EP-A25 and EP-A36 groups, the inflammatory process became more severe as the ingested alcoholic concentration increased. An increase in RANKL immunolabeling and a significantly higher number of TRAP+ cells were also observed. We conclude that chronic alcohol consumption increases the severity of experimental periodontitis in a dose-dependent manner by increasing the magnitude of local inflammatory responses and stimulating alveolar bone resorption.

Impact of Alcohol on Bone Health, Homeostasis and Fracture repair

Purpose of review

Alcohol use continues to rise globally. We review the current literature on the effect of alcohol on bone health, homeostasis and fracture repair to highlight what has been learned in people and animal models of alcohol consumption.

Recent findings

Recently, forkhead box O (FoxO) has been found to be upregulated and activated in mesenchymal stem cells (MSC) exposed to alcohol. FoxO has also been found to modulate Wnt/β-catenin signaling, which is necessary for MSC differentiation. Recent evidence suggests alcohol activates FoxO signaling, which may be dysregulating Wnt/β-catenin signaling in MSCs cultured in alcohol.

Summary

This review highlights the negative health effects learned from people and chronic and episodic binge alcohol consumption animal models. Studies using chronic alcohol exposure or alcohol exposure then bone fracture repair model have explored several different cellular and molecular signaling pathways important for bone homeostasis and fracture repair, and offer potential for future experiments to explore additional signaling pathways that may be dysregulated by alcohol exposure.

CHRONIC CONSUMPTION OF ALCOHOL ADVERSELY AFFECTS THE BONE OF YOUNG RATS

Objective:

To assess the effect of chronic alcohol consumption on the longitudinal growth of the tibia and bone quality parameters in young rats under an experimental setup.

METHODS:

The control (n=10) rats received only water. The ethanol (n=10) rats received ethyl alcohol at concentrations established in the protocol for the induction of chronic alcohol consumption. The blood samples were immediately collected via cardiac puncture and processed to evaluate the levels of alkaline phosphatase by automated spectrophotometry. Following blood sample collection, both tibias were dissected, and weighed; the tibial length was measured., and the samples were stored in a freezer for future analysis of the bone mineral content and mechanical resistance, known as maximal load and stiffness.

RESULTS:

Compromised bone health, with a 35.3% decrease in the serum alkaline phosphatase levels (p < 0.01), a 10% decrease in the tibial mass (p < 0.05), and a 5.3% decrease in the tibial length (p < 0.0001) were noted. Furthermore, a 10% decrease in the bone mineral density was observed (p < 0.01), which led to a 17.2% decrease in the maximum strength (p < 0.01) and 22.6% decrease in stiffness (p < 0.001).

CONCLUSION:

Chronic consumption of alcohol affected the bones of young rats, making them weaker and osteopenic. In addition, the long bones were shorter, suggesting interference with growth. Level of Evidence III, Case Control Study.

Influence of different alcohol intake frequencies on alveolar bone loss in adult rats: A sem study

Background

Alcohol intake is associated with oral diseases and bone changes including alveolar bone loss in humans and in experimental animals. The main aim of the present study is to assess the effect of long-term alcohol intake, at different frequencies, on periodontal bone loss (PBL) in adult rats.

Material and Methods

Thirty-six (36) rats were divided into 3 groups: Control (daily water intake, n=12), daily alcohol intake (20% ethanol, n=12), and social alcohol intake (20% ethanol twice a week, n=12). The rats were sacrificed after 90 days and their right maxillae were removed. Initially, a random portion from each group was analyzed through SEM (scanning electron microscope) to assess surface topography. Next, all pieces were dissected and stained with methylene blue 1% and photographed in stereomicroscope at 10x magnification. The PBL was assessed by measuring the distance between cement-enamel junction and alveolar bone crest.

Results

Results showed higher (p=0.0368) alcohol solution amount in the daily intake group than in the twice week intake one. The SEM showed qualitatively flat bone surface in the control group, the social intake group presented surface with few minor hollows, and the daily intake group evidenced increased number and diameter of wells. The comparison between groups showed higher bone loss (p<0.05) in both frequencies than in the control, but the bone loss was lower (p<0.05) in the social alcohol intake group than in the daily intake one.

Conclusions

Alcohol intake may cause alveolar bone loss in periodontitis-free rats depending on the frequency.

Key words:Alcohol intake, alveolar bone loss, alcohol-induced periodontitis, alcoholic rats.

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.

Effect of Obesity on Bone Healing After Foot and Ankle Long Bone Fractures

As obesity has become more common, fractures in the obese population have become more frequent. Concern exists regarding alterations in bone health and healing in obese patients. A matched case-control study was performed at 1 institution to evaluate whether an association exists between nonunion and a high body mass index in metatarsal and ankle fractures. A total of 48 patients with nonunion were identified, and control patients matched 2 to 1 (n = 96) were selected. The control patients were matched for age, sex, and fracture type. No association was identified between nonunion and the continuous body mass index (p = .23) or morbid obesity, with a body mass index of ≥40 kg/m² (p = .51). However, the results from both univariate and multivariate analysis suggested that patients with a current alcohol problem or a history of an alcohol problem might have a greater risk of nonunion. The odds ratio of a patient with a history of alcohol use experiencing nonunion was 2.7 (95% confidence interval 1.2 to 6.2). Further studies are warranted to confirm these findings.

Effect of the alcohol consumption on osteocyte cell processes: a molecular imaging study

We have previously shown microarchitectural tissue changes with cellular modifications in osteocytes following high chronic alcohol dose. The aim of this study was to assess the dose effect of alcohol consumption on the cytoskeleton activity, the cellular lipid content and modulation of differentiation and apoptosis in osteocyte. Male Wistar rats were divided into three groups: Control (C), Alcohol 25% v/v (A25) or Alcohol 35% v/v (A35) for 17 weeks. Bone mineral density (BMD) was assessed by DXA, osteocyte empty lacunae, lacunae surface, bone marrow fat with bright field microscopy. Osteocyte lipid content was analysed with transmission electron microscopy (TEM) and epifluorescence microscopy. Osteocyte apoptosis was analysed with immunolabelling and TEM. Osteocyte differentiation and cytoskeleton activity were analysed with immunolabelling and real time quantitative PCR. At the end of the protocol, BMD was lower in A25 and A35 compared with C, while the bone marrow lipid content was increased in these groups. More empty osteocyte lacunae and osteocyte containing lipid droplets in A35 were found compared with C and A25. Cleaved caspase-3 staining and chromatin condensation were increased in A25 and A35 versus C. Cleaved caspase-3 was increased in A35 versus A25. CD44 and phosphopaxillin stainings were higher in A35 compared with C and A25. Paxillin mRNA expression was higher in A35 versus A25 and C and sclerostin mRNA expression was higher in A35 versus C. We only observed a dose effect of alcohol consumption on cleaved caspase-3 osteocyte immunostaining levels and on the number of lipid droplets in the bone marrow.

Is the expression of Transforming Growth Factor-Beta1 after fracture of long bones solely influenced by the healing process?

PURPOSE

Circulating TGF-β1 levels were found to be a predictor of delayed bone healing and non-union. We therefore aimed to investigate some factors that can influence the expression of TGF-β1. The correlation between the expression of TGF-β1 and the different socio-demographic parameters was analysed.

METHODS

Fifty-one patients with long bone fractures were included in the study and divided into different groups according to their age, gender, cigarette smoking status, diabetes mellitus and regular alcohol intake. TGF-β1 levels were analysed in patient's serum and different groups were retrospectively compared.

RESULTS

Significantly lower TFG-β1 serum concentrations were observed in non-smokers compared to smokers at week 8 after surgery. Significantly higher concentrations were found in male patients compared to females at week 24. Younger patients had significantly higher concentrations at week 24 after surgery compared to older patients. Concentrations were significantly higher in patients without diabetes compared to those with diabetes at six weeks after surgery. Patients with chronic alcohol abuse had significantly higher concentrations compared to those patients without chronic alcohol abuse.

CONCLUSION

TGF-β1 serum concentrations vary depending upon smoking status, age, gender, diabetes mellitus and chronic alcohol abuse at different times and therefore do not seem to be a reliable predictive marker as a single-point-in-time measurement for fracture healing.

Alcohol and bone: review of dose effects and mechanisms

Alcohol is widely consumed across the world. It is consumed in both social and cultural settings. Until recently, two types of alcohol consumption were recognized: heavy chronic alcohol consumption or light consumption. Today, there is a new pattern of consumption among teenagers and young adults namely: binge drinking. Heavy alcohol consumption is detrimental to many organs and tissues, including bones, and is known to induce secondary osteoporosis. Some studies, however, have reported benefits from light alcohol consumption on bone parameters. To date, little is known regarding the effects of binge drinking on bone health. Here, we review the effects of three different means of alcohol consumption: light, heavy, and binge drinking. We also review the detailed literature on the different mechanisms by which alcohol intake may decrease bone mass and strength. The effects of alcohol on bone are thought to be both direct and indirect. The decrease in bone mass and strength following alcohol consumption is mainly due to a bone remodeling imbalance, with a predominant decrease in bone formation. Recent studies, however, have reported new mechanisms by which alcohol may act on bone remodeling, including osteocyte apoptosis, oxidative stress, and Wnt signalling pathway modulation. The roles of reduced total fat mass, increased lipid content in bone marrow, and a hypoleptinemia are also discussed.

Cortical bone is more sensitive to alcohol dose effects than trabecular bone in the rat

OBJECTIVE

While chronic alcohol consumption is known to decrease bone mineral content (BMC), bone mineral density (BMD), and negatively modify trabecular bone microarchitecture, the impact of alcohol on cortical microarchitecture is still unclear. The aim of this study was to investigate the effects of various doses of alcohol on bone density, trabecular and cortical parameters and bone strength in rats.

METHODS

Forty-eight male Wistar rats were divided into four groups: control (C), alcohol 25% v/v (A25), alcohol 30% v/v (A30) and alcohol 35% v/v (A35). Rats in the alcohol groups were fed a solution composed of ethanol and water for 17 weeks while the control group drank only water. Bone quality and quantity were evaluated through the analysis of density, trabecular and cortical bone microarchitectural parameters, osteocalcin and N-Telopeptide concentrations and a 3-point bending test.

RESULTS

Bone density along with trabecular and cortical thickness were lower in alcohol groups compared to C. BMD was lower in A35 vs. A30 and cortical thickness was lower in A35 vs. A25 and A30. Pore number was increased by alcohol and the porosity was greater in A35 compared to C. N-Telopeptide concentration was decreased in alcohol groups compared to control whereas no differences were observed in osteocalcin concentrations. Maximal energy to failure was lower in A25 and A35 compared to C.

CONCLUSION

Chronic ethanol consumption increases cortical bone damage in rats and may have detrimental effects on bone strength. These effects were dose-dependent, with greater negative effects proportionate to greater alcohol doses.

Low bone accrual is associated with osteocyte apoptosis in alcohol-induced osteopenia

INTRODUCTION

Alcohol is known to decrease bone mineral density (BMD) and to induce trabecular microarchitecture deterioration. However, little is known about the effects of chronic alcohol consumption on osteocytes in situ. The aim of this study was to assess the effects of a high alcohol dose on osteocytes in an alcohol-induced osteopenia model.

MATERIALS AND METHODS

24 male Wistar rats, 2-months old were separated in 2 groups: Control (C) or Alcohol (A35). The rats in the A35 group drank a beverage composed of 35% ethanol v/v mixed to water for 17 weeks. BMD was assessed by DXA, while the microarchitecture was analyzed using μCT. Bone remodeling was studied measuring serum concentration of osteocalcin, NTx and TRAP. Bone marrow adiposity, osteoblastic lineage differentiation, osteocyte morphology and apoptosis were assessed using bright field, epifluorescence, transmission electron and confocal microscopy.

RESULTS

BMD, trabecular thickness, TRAP and NTx concentration were significantly decreased in A35, while cortical thickness was thinner. There were 10 fold more cells stained with cleaved caspase-3, and 35% more empty lacunae in A35, these data indicating a large increase in osteocyte apoptosis in the A35 group. The number of lipid droplets in the marrow was increased in A35 (7 fold). Both the osteocyte apoptosis and the fat bone marrow content strongly correlated with femur BMD (p=0.0017, r = -0.72 and p=0.002, r = -0.70) and whole body BMD.

CONCLUSION

These data suggest that low BMD is associated with osteocyte apoptosis and bone marrow fat content in alcohol-induced osteopenia.

Impaired expansion and multipotentiality of adult stromal cells in a rat chronic alcohol abuse model

It is well established that bone maintenance and healing is compromised in alcoholics. Adult bone marrow-derived stromal cells (BMSCs) and adipose tissue-derived stromal cells (ASCs) likely contribute to bone homeostasis and formation. Direct and indirect alcohol exposure inhibits osteoprogenitor cell function through a variety of proposed mechanisms. The goal of this study was to characterize the effects of chronic alcohol ingestion on the native number and in vitro growth characteristics and multipotentiality of adult BMSCs and ASCs in a rat model. Adult male Sprague-Dawley rats received a liquid diet containing 36% ethanol or an isocaloric substitution of dextramaltose (control). After 4, 8, or 12 weeks of the diet, ASCs were harvested from epididymal adipose tissue and BMSCs from femoral and tibial bone marrow. Cell doublings (CDs) per day and doubling times (DTs) were determined for primary cells (P0) and cell passages 1 through 6 (P1-P6). Fibroblastic (CFU-F), adipogenic (CFU-Ad), and osteogenic (CFU-Ob) colony-forming unit (CFU) frequencies were assessed for P0, P3, and P6. The CDs and DTs were lower and higher, respectively, for ASCs and BMSCs harvested from ethanol versus control rats at all time points. The CFU-F, CFU-Ad, and CFU-Ob were significantly higher in ASCs harvested from control versus ethanol rats for P0, P3, and P6 at all times. Both CFU-Ad and CFU-Ob were significantly higher in P0 BMSCs harvested from control versus ethanol rats after 12 weeks of the diet. The CFU-Ob for P3 BMSCs from control rats was significantly higher than those from ethanol rats after 8 and 12 weeks on the diet. All three CFU frequencies in ASCs from ethanol rats tended to decrease with increasing diet duration. The ASC cell and colony morphology was different between control and ethanol cohorts in culture. These results emphasize the significant detrimental effects of chronic alcohol ingestion on the in vitro expansion and multipotentiality of adult mesenchymal stromal cells (MSCs). Maintenance of the effects through multiple cell passages in vitro suggests cells may be permanently compromised.

Reduced bone formation in alcohol-induced osteopenia is associated with elevated p21 expression in bone marrow cells in aldehyde dehydrogenase 2-disrupted mice

INTRODUCTION

High consumption of alcohol is one of the risk factors for osteoporosis. Approximately 45% of Chinese and Japanese individuals have the inactive aldehyde dehydrogenase 2 (Aldh2) phenotype. The absence of the ALDH2*2 allele is found to adversely influence the risk of osteoporosis. The aim of this study is to clarify the effects of alcohol consumption on osteoblast differentiation in bone marrow and trabecular bone formation in Aldh2-disrupted mice.

MATERIALS AND METHODS

Seven-week-old male Aldh2 knockout mice (Aldh2(-/-)) and wild-type (Aldh2(+/+)) mice were fed with water (groups Aldh2(-/-)/Wa and Aldh2(+/+)/Wa) or with 5% ethanol (groups Aldh2(-/-)/Al and Aldh2(+/+)/Al) for 4 weeks. At the age of 12 weeks, bone histomorphometry was performed at the secondary spongiosa of the tibias. Bone marrow cells from the bilateral femurs and tibias were used for mRNA expression analysis.

RESULTS

Histomorphometrical study revealed that trabecular bone was significantly reduced in the Aldh2(-/-)/Al group compared with that in the Aldh2(-/-)/Wa and Aldh2(+/+)/Wa groups. Bone formation rate was significantly decreased in Aldh2(-/-)/Al compared with the other three groups. Quantitative RT-PCR revealed a significant decrease in type I collagen, osterix, osteopontin, and osteocalcin mRNA expressions in Aldh2(-/-)/Al compared with Aldh2(-/-)/Wa. In bone marrow cell cultures, mineralized nodule formation in Aldh2(-/-)/Al was significantly decreased compared with that in Aldh2(+/+)/Wa and Aldh2(-/-)/Wa, while PAK18, a p21-activated kinase inhibitor, recovered the decreased mineralized nodule formation in Aldh2(-/-)/Al.

CONCLUSION

Alcohol consumption suppressed the differentiation and mineralization of osteoblasts and then reduced trabecular bone formation and bone volume in association with the elevated p21 expression in bone marrow cells, especially in aldehyde dehydrogenase 2-disrupted mice.

Combined effects of chronic alcohol consumption and physical activity on bone health: study in a rat model

Chronic alcohol consumption may be deleterious for bone tissue depending on the amount of ethanol consumed, whereas physical activity has positive effects on bone. This study was designed to analyze the effects of moderate alcohol consumption on bone in trained rats. 48 male Wistar rats were divided into four groups: control (C), alcohol (A), exercise (E) and alcohol + exercise (AE). A and AE groups drank a solution composed of water and ethanol. E and AE groups were trained for 2 months (treadmill: 40 min/day, 5 times/week). Body composition and bone mineral density (BMD) were assessed by dual X-ray absorptiometry and microarchitectural parameters using micro-computed tomography. Serum osteocalcin and CTx were determined by ELISA assays. The body weight and lean mass gain were lower in group A, while the fat mass gain was lower in exercised groups. BMD and BMC were higher with alcohol after body weight adjustment. Trabecular thickness was significantly higher in AE and A groups compared to C and E; cross-sectional area was larger in A and C groups compared to AE and E. CTx levels were higher in A compared to C and in AE and E versus C and A. Osteocalcin levels were significantly greater in AE and E groups versus C and A. In conclusion, the light to moderate alcohol consumption over a short period increased the trabecular thickness, BMC and BMD in A and AE groups. However, we observed alterations in bone remodeling and body composition with alcohol, at the end of the protocol, which did not appear when alcohol was combined to exercise.

Alcohol and the older adult: a comprehensive review

Alcohol consumption in the older adult is of major concern with the advent of baby boomers coming into the over 65-age bracket. Alcohol consumption has been touted as beneficial for health, and while that may be accurate for moderate consumption in younger persons, there is considerable risk associated with increased alcohol intake in older adults. This increase is partially due to age-related physiological changes, existing diagnoses, number of comorbid conditions, and increased use of prescribed and/or over-the-counter medications, coupled with other concerns. This review addresses the current research regarding ethanol consumption in older adults and all-cause mortality as well as several conditions more frequently seen in the geriatric population. These conditions include vascular diseases, hypertension, type 2 diabetes, gastrointestinal disorders, hepatic disorders, dental and oro-facial problems, bone density decline, and falls and fractures. In addition, drug interactions and recent research into select vitamin and mineral considerations with increased alcohol intake in older persons are addressed. While recommendations for alcohol intake have not been specifically established for age ranges within the 65-year-and-older bracket, and practitioners do not routinely assess alcohol intake or ethanol related adverse events in this population, common sense approaches to monitoring will become increasingly important as the generation of "boomers" who believe that alcohol intake improves health comes of age.

Inhibition of NADPH oxidases prevents chronic ethanol-induced bone loss in female rats

Previous in vitro data suggest that ethanol (EtOH) activates NADPH oxidase (Nox) in osteoblasts leading to accumulation of reactive oxygen species (ROS). This might be a mechanism underlying inhibition of bone formation and increased bone resorption observed in vivo after EtOH exposure. In a rat model in which cycling females were infused intragastrically with EtOH-containing liquid diets, EtOH significantly decreased bone formation and stimulated osteoblast-dependent osteoclast differentiation. These effects were reversed by exogenous 17-β-estradiol coadministration. Moreover, coadministration of N-acetyl cysteine (NAC), an antioxidant, or diphenylene iodonium (DPI), a specific Nox inhibitor, also abolished chronic EtOH-associated bone loss. EtOH treatment up-regulated mRNA levels of Nox1, 2, 4, and the receptor activator of nuclear factor-κB ligand (RANKL), an essential factor for differentiation of osteoclasts in bone. Protein levels of Nox4, a major Nox isoform expressed in nonphagocytic cells, was also up-regulated by EtOH in bone. 17-β-Estradiol, NAC, and DPI were able to normalize EtOH-induced up-regulation of Nox and RANKL. In vitro experiments demonstrated that EtOH directly up-regulated Nox expression in osteoblasts. Pretreatment of osteoblasts with DPI eliminated EtOH-induced RANKL promoter activity. Furthermore, EtOH induced RANKL gene expression, and RANKL promoter activation in osteoblasts was ROS-dependent. These data suggest that inhibition of Nox expression and activity may be critical for prevention of chronic EtOH-induced osteoblast-dependent bone loss.

The effect of alcohol consumption on periodontal bone support in experimental periodontitis in rats

Objective:

The aim of this study was to evaluate the effect of the alcohol consumption on the periodontal bone support (PBS) in experimental periodontitis in rats.

Materials and Methods:

Sixty-three male rats were divided into seven groups: G1 (control); G2 (10% ethanol); G3 (nutritional control of G2); G4 (20% ethanol); G5 (nutritional control of G4); G6 (30% ethanol) and G7 (nutritional control of G6). The groups G3, G5 and G7 received controlled diets with equivalent caloric amounts to those consumed in G2, G4 and G6 respectively, with the ethanol replaced by sucrose. After anesthesia, ligatures were installed around the mandibular first molar, leaving the contralateral teeth unligated. After 8 weeks, the rats were killed and their mandibles were radiographed to measure the percentage of PBS on the distal aspect.

Results:

The intragroup analyses showed that presence of ligatures induced periodontitis (p<0.05). Unligated groups did not show significant differences among the percentages of PBS (p=0.1969). However, in ligated groups the rats that received alcohol (G2:48.71%±3.88; G4:47.66%±2.54; G6:47.32%±3.24) and the nutritional control group associated with a high concentration of ethanol (G7:47.40%±3.24) presented a significantly lower percentage of PBS than the other groups (G1:52.40%±2.75; G3:52.83%±2.41; G5:50.85%±4.14).

Conclusions:

These results demonstrated that alcohol consumption in rats may result in a direct effect on alveolar bone loss and increased development of periodontitis. In addition, they suggest that heavy caloric consumption of ethanol may also present an indirect effect on periodontal tissue as a consequence of malnutrition.

Chronic ethanol intake inhibits in vitro osteogenesis induced by osteoblasts differentiated from stem cells

The study investigated whether chronic ethanol (ETH) intake and subsequent ETH exposure of cell cultures affects osteoblast differentiation by evaluating key parameters of in vitro osteogenesis. Rats were treated with 5-20% (0.85-3.43 mm) ETH, increasing by 5% per week for a period of 4 weeks (habituation), after which the 20% level was maintained for 15 days (chronic intake). Bone-marrow stem cells from control (CONT) or ETH-treated rats were cultured in osteogenic medium which was either supplemented (ETH) or not supplemented (CONT) with 1.3 mm ethanol. Thus, four groups relating to rat treatment/culture supplementation were evaluated: (1) CONT/CONT, (2) ETH/CONT, (3) CONT/ETH and (4) ETH/ETH. Cell morphology, proliferation and viability, total protein content, alkaline phosphatase (ALP) activity and bone-like nodule formation were evaluated. Chronic ethanol intake significantly reduced both food and liquid consumption and body weight gain. No difference was seen in cell morphology among treatments. Cell number was affected at 7 and 10 days as follows: CONT/CONT = CONT/ETH < ETH/CONT = ETH/ETH. Doubling time between 3 and 10 days was greater in groups of CONT animals: ETH/ETH = ETH/CONT < CONT/ETH = CONT/CONT. Cell viability and ALP activity were not affected by either animal treatment or culture exposure to ethanol. At day 21, the total protein content was affected as follows: ETH/ETH = CONT/ETH < ETH/CONT = CONT/CONT. Bone-like nodule formation was affected as follows: ETH/ETH < CONT/ETH < ETH/CONT < CONT/CONT. These results show that chronic ethanol intake, followed by the exposure of osteoblasts to ethanol, inhibited the differentiation of osteoblasts, as indicated by an increased proliferation rate and reduced bone-like nodule formation.

Differing effects of acute and chronic stressors on plasma osteocalcin and leptin in rats

Stressor activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis can have profound effects on bone and also appetite and metabolism. We tested in rats the response of plasma osteocalcin (pOC, a bone biomarker that is acutely stress responsive), corticosterone, and leptin to (1) ethanol consumption (5% w/v) in a liquid diet (compared with ad libitum and pair-fed rats), (2) acute restraint, and (3) acute (once, 1 h) and (4) chronic (1 h/day for 7 weeks) social aggression. Basal pOC concentration did not differ with ethanol diet or social interaction, but was elevated by both foot restraint immobilization (Imo) and restraint in wire mesh cylinders (WMR). As previously reported for chronic Imo, ingestion of ethanol blunted the pOC response to Imo. Plasma corticosterone concentration was increased by acute WMR and acute social interaction but was unaltered by chronic social interaction. Plasma leptin concentration was markedly increased by Imo in ad libitum fed, but only slightly in ethanol or pair-fed rats. In contrast, the data reflect significant differences between acute and chronic stressor effects since chronic social stress had little effect on pOC or plasma corticosterone, but tended to decrease leptin level in relation to dominance. Lack of significant impact of prolonged ethanol intake or social aggression suggests physiological adaptation.

Alcohol-induced bone loss and deficient bone repair

BACKGROUND

Chronic consumption of excessive alcohol eventually results in an osteopenic skeleton and increased risk for osteoporosis. Alcoholics experience not only increased incidence of fractures from falls, but also delays in fracture healing compared with non-alcoholics. In this review the term "alcohol-induced bone disease" is used to refer to these skeletal abnormalities. Alcohol-induced osteopenia is distinct from osteoporoses such as postmenopausal osteoporosis and disuse osteoporosis. Gonadal insufficiency increases the rate of bone remodeling, whereas alcohol decreases this rate. Thus, histomorphometric studies show different characteristics for the bone loss that occurs in these two disease states. In particular, alcohol-induced osteopenia results mainly from decreased bone formation rather than increased bone resorption. Human, animal and cell culture studies of the effects of alcohol on bone strongly suggest alcohol has a dose-dependent toxic effect on osteoblast activity. The capacity of bone marrow stromal cells to differentiate into osteoblasts has a critical role in the cellular processes involved in the maintenance of the adult human skeleton by bone remodeling. Chronic alcohol consumption suppresses osteoblastic differentiation of bone marrow cells and promotes adipogenesis. In fracture healing, the effect of alcohol is to suppress synthesis of an ossifiable matrix, possibly due to inhibition of cell proliferation and maldifferentiation of mesenchymal cells in the repair tissue. This results in the deficient bone repair observed in animal studies, characterized by repair tissue of lower stiffness, strength and mineral content. Current knowledge of cellular effects and molecular mechanisms involved in alcohol-induced bone disease is insufficient to develop interventional strategies for its prevention and treatment.

OBJECTIVES

The objectives of this review are 1) to identify the characteristics of alcohol-induced bone loss and deficient bone repair as revealed in human and animal studies, 2) to determine the current understanding of the cellular effects underlying both skeletal abnormalities, and 3) to suggest directions for future studies to resolve current ambiguities regarding the cellular basis of alcohol-induced bone disease.

Effect of ethanol on human osteosarcoma cell proliferatation, differentiation and mineralization

The habitual consumption of even moderate quantities of alcoholic beverages is clearly associated with reduced bone mass, increased prevalence of skeletal fracture and also it is the major risk factor for the development of secondary osteoporosis. The present in vitro study was designed to determine the dose response effects of ethanol on osteoblast-like human osteosarcoma cells (SaOS-2) proliferation, differentiation, mineralization and cyto-toxicity. SaOS-2 cells were plated in 48 and 6 well culture plates and exposed to different concentrations of ethanol (1, 10, 100, 200 and 300 mM) for 24, 48 and 72 h. At the end of incubation, proliferation of cells was studied using crystal violet Bioassay. The cell lysate was utilized to determine ALP activity and conditioned media were used to measure LDH activity. Histochemical localization of ALP and mineralized nodules were studied from cells treated with ethanol (10 and 100 mM) for 21 days. At higher doses, there was a significant reduction in cell number, whereas at lower doses there were variable effects. In 24 h treatment, the higher doses showed a significant increase in ALP activity, whereas 48 and 72 h treatments showed an opposite trend. Ethanol treatment caused a dose- and time-dependent increase in LDH activity. Ethanol treatment altered the quality of mineralization at 10 mM dose whereas completely inhibited mineralization at 100 mM dose, despite the presence of serum. In conclusion, the toxic effect of ethanol is reflected on cell proliferation, differentiation and mineralization even at low doses and at extended treatment duration.

Inhibition of bone repair in a rat model for chronic and excessive alcohol consumption

Alcohol abuse is associated with increases in both the incidence of fractures and complications in fracture healing. The purpose of this study was to determine the dose-dependent effects of ethanol on bone repair in a rat model. Three-month-old male Wistar rats were continuously fed liquid diets containing ethanol as either 36% or 26% of total calories or control diets for 6 weeks. Then, a bone repair model was created in all rats. Bone healing and liver metabolism were evaluated 7 weeks after bone injury. For each dose, there were three ethanol-feeding groups receiving (1) ethanol for 13 weeks, (2) control diet for 13 weeks (pair-fed), and (3) ethanol before bone injury and control diet (pair-fed) after injury. Another group was fed ethanol (36%) before injury and given control diet ad libitum after injury. There were also two nutritional controls consuming control diet and standard rat chow ad libitum for 13 weeks. Abnormal liver metabolism was evident at the higher ethanol dose - increases in cytochrome P4502E1 specific activity (5-fold; P < .01), triglyceride content (4-fold; P < .02), and liver weight (25%; P = .05) - compared with pair-fed controls. The higher dose of ethanol resulted in deficient bone repair when compared with rats receiving ethanol-free control diet by pair-feeding: 26% less (P = .02) rigidity of the repaired bone, 41% less (P = .02) intrinsic stiffness, 24% less intrinsic strength (P = .05), and 14% less (P = .001) ash density of the repair tissue. The reduced food consumption of ethanol-fed rats compared with that in the nutritional controls did not contribute to this deficiency. Furthermore, removal of ethanol (as 36% of calories) from the diet after bone injury completely restored normal bone healing and nearly normalized the liver metabolism. The lower ethanol dose (26% of calories) had a minimal effect on liver metabolism and bone repair. We conclude that ethanol (as 36% of calories) in the rat diet, especially during the postinjury period, was solely responsible for the observed inhibition of bone repair.

The role of nitric oxide on bone metabolism in ovariectomized rats following chronic ethanol intake

This experimental study was designed to examine the effect of nitric oxide (NO) on bone metabolism in ovariectomized rats following chronic ethanol treatment. Chronic ethanol intake was produced by gradual substitution (within 3 weeks) of tap water in diet with 5,10,15 and finally 20% of ethanol. Thereafter, the rats were maintained under these conditions for a duration of 4 months. The rats were divided into two groups. The first group received sham operation (SHAM) and the rats in Group II were ovariectomized (OVX). Five weeks after the SHAM and ovariectomy, the rats were treated with ethanol for 4 months. After this period of ethanol administration, the NOS inhibitor N(W)-nitro-L-arginine methyl ester (L-NAME) was given for three weeks along with ethanol to the same rats. Serum interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, NO, calcium (Ca), phosphorous (P), parathyroid hormone (PTH), 25 HydroxyvitaminD3 [25(OH)D3], alkaline phosphatase (ALP), bone alkaline phosphatase (b-ALP), alanine amino transferase (ALT), aspartate amino transferase (AST), gamma-glutamyltransferase (GGT) levels were measured in different stages of the experiment. IL-1beta, IL-6, TNFalpha and NO levels increased after ethanol administration in SHAM and OVX rats. The decrease in serum Ca was significant while the changes in P, PTH and 25 (OH)D3 levels were not. ALP and b-ALP levels were significantly decreased; ALT, AST and GGT levels were significantly increased. In ovariectomized and SHAM rats, administration of L-NAME together with ethanol, produced a significant increase in IL-1beta, IL-6 and TNFalpha levels. In this group, Ca and P levels were significantly increased, PTH and 25 (OH)D3 levels were significantly decreased. Also, there was a significant decrease in ALT, AST, ALP, b-ALP, and GGT levels. NO increase due to alcohol intake may function as a protective mechanism preventing bone resorption in cases of estrogen insufficiency.

Adipogenic effect of alcohol on human bone marrow-derived mesenchymal stem cells

BACKGROUND

In addition to a decrease in bone mass in alcoholics their osteopenic skeletons show an increase in bone marrow adiposity. Human bone marrow mesenchymal stem cells (hMSC) in vivo differentiate into several phenotypes including osteogenic and adipogenic cells, both of which remain as resident populations of bone marrow. In vitro, the lineage commitment and differentiation of hMSC toward the adipogenic pathway can be promoted by alcohol.

METHODS

Human male and female mesenchymal stem cells from joint replacement surgery were cultured. Cells were grouped as: 1) Control (no additions to the culture medium), 2) EtOH (50 mm alcohol added to the culture medium), 3) OS (osteogenic inducers added to the culture medium), and 4) OS + EtOH (osteogenic inducers and 50 mm alcohol added to the culture medium). Cultures stained with Nile Red confirmed the development of differentiated adipocytes. Population analysis was performed using fluorescence-activated cell sorting. Gene expression of early, middle, late, and terminal differentiation stage markers (PPAR)gamma2, lipoprotein lipase, adipsin, leptin, and adipocyte P2 (aP2)] was studied by Northern hybridization, and protein synthesis of aP2 was determined by Western analysis.

RESULTS

Nile red staining confirmed increased adipocyte development 10 days after the onset of treatment with 50 mm alcohol and osteogenic induction. By day 21 the number of adipocytes increased to 13.6% of the total population. Alcohol up-regulated the gene expression of PPARgamma2 whereas no up-regulation was observed for the other genes. Protein production of aP2 was significantly increased in hMSC cells by culture in the presence of alcohol.

CONCLUSIONS

The data suggest that alcohol's adipogenic effect on cultured hMSC is through up-regulation of PPARgamma2 at the point of lineage commitment as well as through enhancement of lipid transport and storage through increased aP2 synthesis. The alcohol-induced expression and synthesis changes account for the increased Nile red staining of cultured hMSC.

Alcohol Intake and Osseointegration Around Implants: A Histometric and Scanning Electron Microscopy Study

Alveolar wound healing can be modified by local and systemic factors. The aim of this study was to evaluate the possible effect of alcoholic beverage administration (sugarcane brandy) on reparative bone formation around hydroxyapatite/tricalcium phosphate implants inside the alveolar socket. Male Wistar rats had their upper right incisors extracted and the bioceramic granules implanted in the alveoli. The animals received increasing concentrations of brandy until 30 degrees Gay-Lussac was achieved starting 30 days before dental extraction and maintained for periods varying from 1 hour to 6 weeks, until sacrifice. Blood alcohol concentration analysis was performed as well as histological and histometric analysis through light and scanning electron microscopy to examine the relation between alveolar healing components, including new bone trabeculae, and the implants. Blood alcohol concentration was significantly higher in treated animals compared with controls. A significant delay in reparative bone formation was detected in the alveolus of alcoholic rats by a histometric differential point counting method, whereas the presence of the bioceramic in the alveolar socket improved alveolar wound healing in alcohol-treated rats. It is suggested that the osteoconductive properties of this bioceramic accelerated alveolar wound healing in alcoholic rats.

Modulation of distraction osteogenesis in the aged rat by fibroblast growth factor

This study explores a series of hypotheses related to modulation of bone formation using the distraction model. The tibial lengthening model was scaled down from dog to rat to use immunohistochemistry, in situ hybridization, and reverse transcription-polymerase chain reaction to evaluate cellular events during in vivo bone formation. Different delivery systems such as oral, intragastric, intravenous, subcutaneous, and local diffusion by either extraperiosteal or intramedullary routes, were developed and standardized. Systemic modulators, including diet (total enteral nutrition, calcium, phosphate, soy, whey, casein, lead, and alcohol) and hormones (estrogen, testosterone, growth hormone, and gonadectomy), were tested. To investigate the effects of aging on bone formation, rats of different age groups had tibial lengthening. The aging effect could be distinguished by a reproducible deficiency of endosteal bone formation, consistent with similar deficits in older adult patients having distraction osteogenesis or in patients with senile osteoporosis. Expression of endogenous fibroblast growth factor-2 at the cellular level during the coupled osteogenesis and angiogenesis in young rats was dramatically diminished in old rats. Exogenous fibroblast growth factor-2 reversed the endosteal deficits found in old rats having distraction osteogenesis.

Skeletal toxicity associated with chronic ethanol exposure in a rat model using total enteral nutrition

Chronic alcohol abuse decreases bone mass, inhibits osteoblast differentiation and function, increases fracture incidence, and delays fracture healing. Four studies were designed to use intragastric ethanol delivery as part of a total enteral nutrition (TEN) system to determine the negative systemic effects of chronic ethanol on 1) the rat skeleton and 2) local rapid bone formation during limb lengthening (distraction osteogenesis, DO). In study 1, three-point bending tests demonstrated that after 75 days of ethanol exposure, the tibiae had significantly lower load to failure versus control diet (p = 0.0006) or ad libitum chow-fed rats (p = 0.0029). Study 2 examined alcohol's effects on the density and cross-sectional area of the proximal tibial metaphysis using peripheral quantitative computed tomography and found that after 25 days of ethanol exposure the trabecular volumetric bone mineral density (p = 0.011) and cortical cross-sectional area (p = 0.011) were lower compared with controls. In study 3, a comparison of distracted tibial radiographs and histological sections demonstrated ethanol-related decreases in both gap mineralization (p = 0.03) and bone column formation (p = 0.01). Histological comparisons in study 4 reproduced the ethanol-related deficits in new bone formation during DO (p = 0.001). These results indicate that the TEN system is a viable model to study ethanol's effects on the skeleton and that chronic ethanol delivery via TEN decreases trabecular bone density, cortical area, and mature bone strength. Also, the DO studies demonstrate, for the first time, that chronic ethanol inhibits rapid bone formation during limb lengthening.

Effects of binge ethanol administration on the behavioral outcome of rats after lateral fluid percussion brain injury

This study examined the effects of 4 weeks of binge ethanol administration (BEAn) on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were intragastrically given 7.5 mL/kg of either 40% ethanol in 5% glucose solution (3 g ethanol/kg; binge ethanol group), or 5% glucose solution (vehicle group), twice on Thursday and Friday of 3 consecutive weeks. Then rats from both groups were subjected to either lateral FP brain injury of moderate severity (1.8 atm) or to sham operation. Postinjury behavioral measurements revealed that brain injury caused significant spatial learning disability in both groups. There were no significant differences in mean search latencies in the sham animals between the vehicle and binge ethanol groups. On the other hand, the mean search latency of the binge ethanol group was significantly higher than that of the vehicle group in trial blocks 2 and 4. There were no significant differences in the target visits (expressed as mean zone difference [MZD]) during the probe trial between the injured animals of binge ethanol and vehicle groups. However, there was only a minor trend towards worsened MZD score in the binge-injured animals. Histologic analysis of injured animals from both injured ethanol and vehicle groups revealed similar extents of ipsilateral cortical and observable hippocampal damage. These results suggest that 4 weeks of binge ethanol treatment followed by ethanol intoxication at the time of injury worsens some aspects of the spatial learning ability of rats. This worsening is probably caused by subtle, undetectable morphologic damage by binge ethanol administration.

Skeletal response to alcohol

This review briefly assesses the well-established effects of alcohol consumption on bone and mineral metabolism and addresses areas of controversy that need additional research. Alcohol consumption is a risk factor for osteoporosis based on the frequent finding of a low bone mass, decreased bone formation rate, and increased fracture incidence in alcoholics. Alcohol also has been shown to reduce bone formation in healthy humans and animals and to decrease proliferation of cultured osteoblastic cells. On the other hand, it has been difficult to demonstrate alcohol-induced bone loss and increased fracture rate in population-based studies. Indeed, most population-based studies have shown a positive association between alcohol and bone mass and no change or a decrease in fracture risk. Overall, the evidence generally supports a detrimental effect of chronic alcohol abuse on the skeleton of men and a neutral or generally beneficial effect of light to moderate alcohol consumption, especially in older women. This latter putative beneficial effect may be due to a reduction in the age-related increase in bone remodeling associated with postmenopausal bone loss. Specific areas of research are recommended to clarify the dose and sex effects of alcohol consumption and to determine cellular and molecular mechanisms of action. The goals of this proposed research emphasis are to determine the degree of risk for the range of alcohol consumption, to set guidelines of consumption compatible with maintaining bone health, and to develop appropriate countermeasures to prevent or reverse the detrimental skeletal effects of alcohol abuse.

Moderate alcohol consumption suppresses bone turnover in adult female rats

Chronic alcohol abuse is a major risk factor for osteoporosis but the effects of moderate drinking on bone metabolism are largely uninvestigated. Here, we studied the long-term dose-response (0, 3, 6, 13, and 35% caloric intake) effects of alcohol on cancellous bone in the proximal tibia of 8-month-old female rats. After 4 months of treatment, all alcohol-consuming groups of rats had decreased bone turnover. The inhibitory effects of alcohol on bone formation were dose dependent. A reduction in osteoclast number occurred at the lowest level of consumption but there were no further reductions with higher levels of consumption. An imbalance between bone formation and bone resorption at higher levels of consumption of alcohol resulted in trabecular thinning. Our observations in rats raise the concern that moderate consumption of alcoholic beverages in humans may reduce bone turnover and potentially have detrimental effects on the skeleton.

Alendronate administration and skeletal response during chronic alcohol intake in the adolescent male rat

Alendronate is an aminobisphosphonate that inhibits bone resorption in osteoporotic humans and rats but does not induce osteomalacia. Several bisphosphonates, including alendronate, also have direct positive actions on osteoblasts, bone formation, and mineralization. We studied the effects of alendronate on skeletal development in adolescent male rats during chronic alcohol intake. Four groups of age- and weight-matched male Sprague-Dawley rats (35 days of age) were fed the Lieber-DeCarli diet containing 36% of calories as EtOH (E), the EtOH diet plus 60 mg/kg alendronate (EA) every other day intraperitoneally (ip), an isocaloric diet (I), or the isocaloric diet plus 60 mg/kg alendronate (IA) every other day ip. Body weight, femur length, serum levels of osteocalcin (OC), insulin-like growth factor 1 (IGF-1), testosterone, and luteinizing hormone (LH); femur distal metaphyseal and middiaphyseal bone mineral density (BMD) and tibial metaphyseal gene expression for alpha-1-type I collagen (Col I), OC, and bone alkaline phosphatase (AP); and femur strength by four-point bending to failure were measured after 28 days of feeding and alendronate injections. Serum alcohol levels at death were 156 +/- 13 mg/dl (E) and 203 +/- 40 mg/dl (EA). Alendronate given to alcohol-fed rats increased metaphyseal BMD by more than 3-fold over rats fed alcohol alone. Alendronate given to isocaloric pair-fed rats increased metaphyseal BMD by more than 2.5-fold over rats fed the isocaloric diet alone. Cortical BMD was reduced by alcohol but was increased by alendronate. Alcohol consumption reduced serum IGF-1 levels, and alendronate increased IGF-1 levels in alcohol-fed rats. Serum OC, testosterone, and LH were unaffected by alcohol and alendronate. Quantitative dot blot hybridization using rat complementary DNA (cDNA) probes and normalization against 18S subunit ribosomal RNA (rRNA) levels revealed no changes in tibial metaphyseal gene expression for type I collagen, osteocalcin, or alkaline phosphatase. Alcohol significantly reduced the biomechanical properties of the femurs that were partially compensated by alendronate. Chronic alcohol consumption uncouples formation from ongoing resorption, and resorption is inhibited by alendronate. However, alendronate's positive effects on osteoblast-mediated mineralization during chronic alcohol consumption point to the potential use of bisphosphonates in the treatment of decreased bone formation secondary to alcohol-induced diminished osteoblast function.

Binge drinking and bone metabolism in a young actively growing rat model

BACKGROUND

Chronic alcohol consumption has been demonstrated to be deleterious to bone health. However, binge drinking is the prevalent form of drinking in young people, which was the impetus for the present study to determine the effect of week-end and week-long binge drinking on bone health in a young actively growing animal model.

METHODS

Four-week-old, female, Sprague-Dawley rats were given the amount of 5% alcohol by gavage to be equivalent to a 63 kg woman drinking six beers a day for either 2 or 5 consecutive days per week.

RESULTS

There were no changes in the 5-day binge animals, but the 2-day binge animals were hypocalcemic. Similarly, 2-day binge animals had slightly increased bone chemistry and histomorphometric values for both tibia and femur, but only femur length, dry weight, and ash weight as well as femur density, presented either as g/ml or ash weight per unit volume, were increased by a statistically significant level. Cross-section periosteal Mineral Apposition Rate (MAR) was significantly decreased in the 2-day alcohol fed animals.

CONCLUSIONS

Actively growing rats given 5% alcohol by gavage for 2 days per week have an increased bone length, bone weight, and bone density. The interpretation of these results must be viewed with great caution because studies of chronic alcohol consumption, and many studies of acute drinking, clearly indicate deleterious effects of alcohol on bone health. Those fed alcohol for 5 days per week showed no change.