Serum osteoprotegerin and RANKL levels in chronic alcoholic liver disease

Osteoprotegerin is an Early Marker of the Fibrotic Process and of Antifibrotic Treatment Responses in Ex Vivo Lung Fibrosis

BACKGROUND

Lung fibrosis is a chronic lung disease with a high mortality rate with only two approved drugs (pirfenidone and nintedanib) to attenuate its progression. To date, there are no reliable biomarkers to assess fibrosis development and/or treatment effects for these two drugs. Osteoprotegerin (OPG) is used as a serum marker to diagnose liver fibrosis and we have previously shown it associates with lung fibrosis as well.

METHODS

Here we used murine and human precision-cut lung slices to investigate the regulation of OPG in lung tissue to elucidate whether it tracks with (early) fibrosis development and responds to antifibrotic treatment to assess its potential use as a biomarker.

RESULTS

OPG mRNA expression in murine lung slices was higher after treatment with profibrotic cytokines TGFβ1 or IL13, and closely correlated with Fn and PAI1 mRNA expression. More OPG protein was released from fibrotic human lung slices than from the control human slices and from TGFβ1 and IL13-stimulated murine lung slices compared to control murine slices. This OPG release was inhibited when murine slices were treated with pirfenidone or nintedanib. OPG release from human fibrotic lung slices was inhibited by pirfenidone treatment.

CONCLUSION

OPG can already be detected during the early stages of fibrosis development and responds, both in early- and late-stage fibrosis, to treatment with antifibrotic drugs currently on the market for lung fibrosis. Therefore, OPG should be further investigated as a potential biomarker for lung fibrosis and a potential surrogate marker for treatment effect.

Clinical Indicators of Bone Deterioration in Alcoholic Liver Cirrhosis and Chronic Alcohol Abuse: Looking beyond Bone Fracture Occurrence

Although previous studies indicated that chronic alcohol abuse (CAA) and alcoholic liver cirrhosis (ALC) are associated with increased bone fragility, understanding bone fragility determinants is still modest in these individuals. We used a comprehensive individualized clinical fracture risk assessment approach (vertebral osteodensitometry, femoral osteodensitometry and geometry, and serum bone turnover biomarkers) to compare adult male patients with ALC who have not previously had femoral or vertebral fractures (n = 39), patients with CAA (without liver cirrhosis, n = 78) who have not previously had femoral or vertebral fractures and healthy age- and sex-matched controls (n = 43). Our data suggested that intertrochanteric bone mineral density was significantly lower in ALC and CAA patients than in controls. Also, the trabecular bone score was considerably lower in ALC patients compared with CAA and control individuals. The most significant inter-group differences in femoral geometry were noted on the femoral shaft. Patients with ALC and CAA have a higher 10-year risk of major osteoporotic fractures compared to the controls. Analysis of bone turnover biomarkers showed increased osteoprotegerin and beta-C-terminal telopeptide serum concentrations and decreased insulin growth factor-1 concentrations in patients with ALC compared to CAA and control groups. Our data revealed that bone alterations are present in patients with ALC and CAA even if they did not sustain a nontraumatic bone fracture, but it is also indicative that current bone-assessing clinical methods are not entirely reliable. Thus, future studies should focus on developing a reliable integrative clinical tool that can be used to accurately predict and prevent bone fracture occurrences in patients with ALC and CAA.

OPG/RANK/RANKL axis relation to cardiac iron-overload in children with transfusion-dependent thalassemia

OPG/RANK/RANKL axis was reportedly involved in initiating various diseases, especially bone and cardiovascular diseases. This study aimed to assess the relationship between some OPG, RANK, and RANKL polymorphisms and alleles and iron-overload-induced cardiomyopathy in children with transfusion-dependent thalassemia (TDT). This study included 80 TDT children and 80 age and sex-matched controls. Real-time PCR was done for rs207318 polymorphism for the OPG gene and rs1805034, rs1245811, and rs75404003 polymorphisms for the RANK gene, and rs9594782 and rs2277438 polymorphisms for the RANKL gene. Cardiac T2* MRI and ejection fraction (EF) were done to assess the myocardial iron status and cardiac function. In this study, there were no significant differences in frequencies of the studied polymorphisms between cases and controls (p > 0.05 in all). In TDT children, OPG rs2073618 (G > C) had a significant relation to myocardial iron overload (p = 0.02). Its C allele had significantly more frequent normal EF than its G allele (p = 0.04). RANK rs75404403 (C > DEL) had a significant relation to cardiac dysfunction (p = 0.02). Moreover, the C allele of that gene had significantly more frequent affected EF than its DEL allele (p = 0.02). The A allele of RANKL rs2277438 (G > A) had significantly less frequent severe cardiac iron overload than the G allele (p = 0.04). In conclusion, the OPG/ RANK/RANKL genes may act as genetic markers for iron-induced cardiomyopathy in TDT children. Some of the studied genes' polymorphisms and alleles were significantly related to myocardial iron overload and cardiac dysfunction in TDT children.

Bone disease in patients with cirrhosis of different etiology and severity; are Klotho protein and osteoprotegerin potential biomarkers?

BACKGROUND AND AIMS

Cirrhosis is associated with increased risk for osteoporosis and osteopenia. This study aims to further investigate this relationship by examining if etiology and severity of cirrhosis are independent predictors of bone mineral density (BMD) loss. Furthermore we examined the serum levels of osteoprotegerin (OPG) and Klotho proteins that have been involved in bone metabolism.

METHODS

Seventy-four patients with cirrhosis of different etiology and 25 matched healthy controls were included in this study. Bone mineral densitometry at both lumbar spine and femoral neck was measured. Serum total OPG, Klotho protein and vitamin D levels were also determined. Comparisons were performed according to etiology and severity of cirrhosis.

RESULTS

Decreased bone density was observed in cirrhotic patients compared to healthy controls with T = -1.46 and T = -1.37 in lumbar spine and femoral bone respectively compared to T = -0.396 and T = -0.672 in the control group. In the cirrhotic group, osteopenia was observed in 46% in lumbar spine and 51% in femoral bone whereas osteoporosis was observed in 20% in lumbar spine and 9% in femoral bone. Decreased bone density was confirmed, regardless of cirrhosis etiology or stage of liver function. Patients were found to have higher levels of OPG than the control group (136 pg/ml vs. 67 pg/ml, p < 0.001), but lower levels of Klotho protein (1051 pg/ml vs. 1842 pg/ml, p < 0.001) regardless etiology and severity of cirrhosis. High OPG levels were found to be associated with low femoral bone density.

CONCLUSIONS

BMD is lower in cirrhotic patients regardless etiology and severity of liver disease with osteopenia and osteoporosis be present in 50% and 20%, respectively. Higher levels of OPG and lower levels of Klotho protein were observed in cirrhotic patients regardless etiology and severity in comparison to matched healthy group.

Patients With Cirrhosis Have Elevated Bone Turnover but Normal Hepatic Production of Osteoprotegerin

CONTEXT

Severe osteodystrophy is common in patients with liver dysfunction. Markers of bone metabolism may help in early diagnosis of osteodystrophy and in understanding underlying pathophysiological mechanisms.

OBJECTIVE

To elucidate changes in bone metabolism associated with cirrhosis and to determine the route of elimination for the markers.

METHODS

Case-control study at a public university hospital. Fifty-nine patients with cirrhosis (47 alcoholic and 12 nonalcoholic cirrhosis) and 20 controls were included. Participants underwent catheterization of the femoral artery, and the hepatic, renal, and femoral veins with collection of blood from all 4 sites. Regional arteriovenous differences in concentrations of bone metabolism markers were determined: procollagen of type I collagen propeptide (PINP), C-terminal cross-linking telopeptide of type I collagen (CTX), osteocalcin, tartrate-resistant acid phosphatase isoform 5b (TRAcP5b), osteoprotegerin (OPG), and sclerostin and correlated with degree of disease (Child-Pugh classification).

RESULTS

PINP concentration was higher (median: 87.9 µg/L) in patients with cirrhosis than in controls (52.6 µg/L) (P = .001), while hepatic extraction was lower (4.3% vs 14.5%) (P < .001). Both CTX and TRAcP5b were higher in patients with cirrhosis (340 ng/L and 3.20 U/L) than in controls (215 ng/L and 1.60 U/L) (P < .001 and P < .0001). Hepatic sclerostin extraction was lower in patients with cirrhosis (14.6%) than in controls (28.7%) (P < .0001). In both groups OPG showed a hepatic release rate (production) of 6%.

CONCLUSION

Patients with cirrhosis have increased bone resorption, but unaltered bone formation. Sclerostin is eliminated through the liver while OPG is produced in the liver. Bone markers may prove useful in evaluating bone turnover in patients with cirrhosis.

Assessment of bone metabolism biomarkers in serum and saliva of cirrhotic patients

OBJECTIVE

To assess the serum and salivary levels of biomarkers related to bone metabolism in cirrhotic patients as well as the evidence of osteoporotic changes on panoramic radiographs.

MATERIALS AND METHODS

Thirty-eight cirrhotic patients underwent anamnesis and physical examination. Specimens of blood and saliva were collected for evaluation by using Luminex™ xMAP technology to quantify RANKL, OPG, IL-1β, IL-6 and TNF-α. Panoramic radiographs were evaluated based on the mandibular cortical index (MCI) and the resulting data were compared to the expression of biomarkers in serum and saliva. Descriptive data analysis was performed and the Mann-Whitney's test and Spearman's correlation were used.

RESULTS

Most of the sample consisted of males (68.4%) who had cirrhosis mostly resulting from alcoholism (28.9%). Median concentration values of RANKL (74.44 pg/mL), IL-1 β (45.91 pg/mL), IL-6 (67.69 pg/mL) and TNF-α (5.97 pg/mL) in saliva were higher than those observed in serum. In 72.7% of the panoramic radiographs, MCI was found to be suggestive of osteoporotic changes. No statistically significant correlation was observed between salivary and serum expressions of biomarkers or between biomarkers and MCI.

CONCLUSION

RANKL, OPG, IL-1β, IL-6 and TNF-α are expressed differently in serum and saliva and the concentration of these biomarkers is not related to MCI.

CLINICAL RELEVANCE

This study contributes to the study of the mechanisms of osteoporosis in cirrhotic individuals.

The role of osteoprotegerin (OPG) in fibrosis: its potential as a biomarker and/or biological target for the treatment of fibrotic diseases

Fibrosis is defined by excessive formation and accumulation of extracellular matrix proteins, produced by myofibroblasts, that supersedes normal wound healing responses to injury and results in progressive architectural remodelling. Fibrosis is often detected in advanced disease stages when an organ is already severely damaged and can no longer function properly. Therefore, there is an urgent need for reliable and easily detectable markers to identify and monitor fibrosis onset and progression as early as possible; this will greatly facilitate the development of novel therapeutic strategies. Osteoprotegerin (OPG), a well-known regulator of bone extracellular matrix and most studied for its role in regulating bone mass, is expressed in various organs and functions as a decoy for receptor activator of nuclear factor kappa-B ligand (RANKL) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Recently, OPG has been linked to fibrosis and fibrogenesis, and has been included in a panel of markers to diagnose liver fibrosis. Multiple studies now suggest that OPG may be a general biomarker suitable for detection of fibrosis and/or monitoring the impact of fibrosis treatment. This review summarizes our current understanding of the role of OPG in fibrosis and will discuss its potential as a biomarker and/or novel therapeutic target for fibrosis.

Effects of graded increases in ethanol consumption on biochemical markers of bone turnover in young adult male cynomolgus macaques

Chronic heavy alcohol use is often associated with reduced bone mineral density and altered bone turnover. However, the dose response effects of ethanol on bone turnover have not been established. This study examined the effects of graded increases of ethanol consumption on biochemical markers of bone turnover in young adult male cynomolgus macaques (Macaca fascicularis). For this study, 6.6-year-old (95% CI: 6.5, 6.7) male macaques were subjected to three 30-day sessions of increased ethanol intake over a 90-day interval. During the first 30 days, the monkeys drank a predetermined volume of ethanol corresponding to 0.5 g/kg/day, followed by 1.0 g/kg/day and 1.5 g/kg/day. Osteocalcin, a marker of bone formation, and carboxyterminal cross-linking telopeptide of type 1 collagen (CTX), a marker of resorption, were measured during each 30-day session. In addition, the ratio of osteocalcin to CTX was determined as a surrogate measure of global turnover balance. Mean osteocalcin decreased by 2.6 ng/mL (1.8, 3.5) for each one-half unit (0.5 g/kg/day) increase in dose (p < 0.001). Mean CTX decreased by 0.13 ng/mL (0.06, 0.20) for each one-half unit increase in dose (p < 0.001). Furthermore, there was an inverse relationship between dose and the ratio of osteocalcin to CTX, such that the mean ratio decreased by 0.9 (0.3, 1.5) for each one-half unit increase in dose (p = 0.01). In summary, male cynomolgus macaques had decreased blood osteocalcin and CTX, and osteocalcin to CTX ratio during the 90-day interval of graded increases in ethanol consumption, indicative of reduced bone turnover and negative turnover balance, respectively. These findings suggest that over the range ingested, ethanol resulted in a linear decrease in bone turnover. Furthermore, the negative bone turnover balance observed is consistent with reported effects of chronic alcohol intake on the skeleton.

Association of serum osteoprotegerin with severity of chronic liver disease in female patients: A potential biomarker

Objective

To determine the association of serum osteoprotegerin (OPG) with the severity of chronic liver disease in female patients.

Methods

This case-control study was conducted in Madina Teaching Hospital from 2019-2020.An institutional review board of University Medical and Dental College, The University of Faisalabad gave the approval to conduct the study. Only female patients of age group 40 to 60 years having CLD were included in this study. Total 80 participants were enrolled after fulfilling the inclusion and exclusion criteria. Serum OPG levels were measured by enzyme linked immunosorbant assay (ELISA) supplied by ELAB Sciences, USA. The severity of disease was assessed by Child-Pugh classification.

Results

OPG levels were significantly different between the three Child-Pugh classes. OPG levels were significantly high in class C indicating increased level of this cytokine in CLD as compared to class A (p = <0.05). There was a positive association of OPG with splenomegaly (OR = 2.10, p = <0.001), hepatomegaly (OR = 4.41, (p = <0.05), skin pigmentation (OR = 2.06, p = <0.05), malena (OR = 1.87, p = <0.05) and prolonged bleeding (OR = 1.86, p = <0.05).

Conclusion

The levels of serum Osteoprotegerin is increased in severe form of chronic liver disease (Class C) of Child-Pughs classification as compared to mild (Class A) and moderate (Class B) forms of Child-Pughs classification.

Osteoprotegerin is More than a Possible Serum Marker in Liver Fibrosis: A Study into its Function in Human and Murine Liver

Osteoprotegerin (OPG) serum levels are associated with liver fibrogenesis and have been proposed as a biomarker for diagnosis. However, the source and role of OPG in liver fibrosis are unknown, as is the question of whether OPG expression responds to treatment. Therefore, we aimed to elucidate the fibrotic regulation of OPG production and its possible function in human and mouse livers. OPG levels were significantly higher in lysates of human and mouse fibrotic livers compared to healthy livers. Hepatic OPG expression localized in cirrhotic collagenous bands in and around myofibroblasts. Single cell sequencing of murine liver cells showed hepatic stellate cells (HSC) to be the main producers of OPG in healthy livers. Using mouse precision-cut liver slices, we found OPG production induced by transforming growth factor β1 (TGFβ1) stimulation. Moreover, OPG itself stimulated expression of genes associated with fibrogenesis in liver slices through TGFβ1, suggesting profibrotic activity of OPG. Resolution of fibrosis in mice was associated with decreased production of OPG compared to ongoing fibrosis. OPG may stimulate fibrogenesis through TGFβ1 and is associated with the degree of fibrogenesis. It should therefore be investigated further as a possible drug target for liver fibrosis or biomarker for treatment success of novel antifibrotics.

Risk factors for bone loss in juvenile-onset systemic lupus erythematosus: a prospective study

OBJECTIVE

Juvenile-onset systemic lupus erythematosus (JoSLE) is associated with low bone mass for age and fractures; nevertheless, risk factors for bone impairment are poorly understood. The aim of this study was to evaluate risk factors for bone mass loss in JoSLE patients.

METHODS

Forty-nine female JoSLE patients were evaluated at baseline and after a 3.5-year follow-up regarding clinical, laboratory (including bone turnover markers), areal bone mineral density (aBMD) and bone microarchitecture parameters using high-resolution peripheral quantitative computed tomography (HR-pQCT). Based on the difference between final and baseline aBMD value, the patients were divided into three groups: aBMD gain (BG), aBMD loss (BL) and aBMD no change (NC).

RESULTS

The mean patient age was 18.7 ± 3.3 years. Sixty-one percent of patients presented with aBMD gain, 18.4% aBMD loss, and 20.4% remained stable during this follow-up period. Comparing the BL with the BG group, there was a higher frequency of alcohol consumption (p = 0.009), a higher frequency of inadequate calcium intake (p = 0.047) and lower levels of baseline procollagen type 1 amino-terminal propeptide (P1NP) (p = 0.036) in the BL group. Moreover, worsening of HR-pQCT parameters trabecular volumetric density (p = 0.003) and cortical thickness (p = 0.009) was observed in the BL group. In addition, a higher frequency of renal activity was observed comparing the BL + NC with the BG group (p = 0.036).

CONCLUSIONS

This is the first longitudinal study that has analyzed the risk factors of bone loss in JoSLE patients. The authors emphasize the importance of evaluating lifestyle habits and renal disease activity in these young women. Furthermore, this study suggests that trabecular and cortical compartments deteriorated, and low levels of P1NP may be a predictor of bone impairment in JoSLE.

Creation of RANKL mutants with low affinity for decoy receptor OPG and their potential anti-fibrosis activity

Fibrosis is characterized by the progressive alteration of the tissue structure due to the excessive production of extracellular matrix (ECM). The signaling system encompassing Receptor Activator of Nuclear factor NF‐κB Ligand (RANKL)/RANK/Osteoprotegerin (OPG) was discovered to play an important role in the regulation of ECM formation and degradation in bone tissue. However, whether and how this signaling pathway plays a role in liver or pulmonary ECM degradation is unclear up to now. Interestingly, increased decoy receptor OPG levels are found in fibrotic tissues. We hypothesize that RANKL can stimulate RANK on macrophages and initiate the process of ECM degradation. This process may be inhibited by highly expressed OPG in fibrotic conditions. In this case, RANKL mutants that can bind to RANK without binding to OPG might become promising therapeutic candidates. In this study, we built a structure‐based library containing 44 RANKL mutants and found that the Q236 residue of RANKL is important for OPG binding. We show that RANKL_Q236D can activate RAW cells to initiate the process of ECM degradation and is able to escape from the obstruction by exogenous OPG. We propose that the generation of RANKL mutants with reduced affinity for OPG is a promising strategy for the exploration of new therapeutics against fibrosis.

Hepatic Osteodystrophy-Molecular Mechanisms Proposed to Favor Its Development

Almost all patients with chronic liver diseases (CLD) show altered bone metabolism. Depending on the etiology, this manifests in a severe osteoporosis in up to 75% of the affected patients. Due to high prevalence, the generic term hepatic osteodystrophy (HOD) evolved, describing altered bone metabolism, decreased bone mineral density, and deterioration of bone structure in patients with CLD. Once developed, HOD is difficult to treat and increases the risk of fragility fractures. Existing fractures affect the quality of life and, more importantly, long-term prognosis of these patients, which presents with increased mortality. Thus, special care is required to support the healing process. However, for early diagnosis (reduce fracture risk) and development of adequate treatment strategies (support healing of existing fractures), it is essential to understand the underlying mechanisms that link disturbed liver function with this bone phenotype. In the present review, we summarize proposed molecular mechanisms favoring the development of HOD and compromising the healing of associated fractures, including alterations in vitamin D metabolism and action, disbalances in transforming growth factor beta (TGF-β) and bone morphogenetic protein (BMP) signaling with histone deacetylases (HDACs) as secondary regulators, as well as alterations in the receptor activator of nuclear factor kappa B ligand (RANKL)–osteoprotegerin (OPG) system mediated by sclerostin. Based on these mechanisms, we give an overview on the limitations of early diagnosis of HOD with established serum markers.

Influence of experimental alcoholism on the repair process of bone defects filled with beta-tricalcium phosphate

This study evaluated the effect of ethanol on the repair in calvaria treated with beta-tricalcium phosphate (β-TCP). Forty rats were distributed into 2 groups: Water group (CG, n = 20) and Alcohol Group (AG, n = 20), which received 25% ethanol ad libitum after an adaptation period of 3 weeks. After 90 days of liquid diet, the rats were submitted to a 5.0 mm bilateral craniotomy in the parietal bones; the left parietal was filled with β-TCP (CG-TCP and AG-TCP) and the contralateral only with blood clot (CG-Clot and AG-Clot). The animals were killed after 10, 20, 40 and 60 days. The groups CG-Clot and AG-Clot showed similar pattern of bone formation with a gradual and significant increase in the amount of bone in CG-Clot (22.17 ± 3.18 and 34.81 ± 5.49) in relation to AG-Clot (9.35 ± 5.98 and 21.65 ± 6.70) in periods of 20-40 days, respectively. However, in the other periods there was no statistically significant difference. Alcohol ingestion had a negative influence on bone formation, even with the use of β-TCP, exhibiting slow resorption and replacement by fibrous tissue, with 16% of bone formation within 60 days in AG-TCP, exhibiting immature bone tissue with predominance of disorganized collagen fibers. Defects in CG-TCP showed bone tissue with predominance of lamellar arrangement filling 39% of the original defect. It can be concluded that chronic ethanol consumption impairs the ability to repair bone defects, even with the use of a β-TCP biomaterial.

High Prevalent Hypovitaminosis D Is Associated with Dysregulation of Calcium-parathyroid Hormone-vitamin D Axis in Patients with Chronic Liver Diseases

Background and Aims: Although hypovitaminosis D is common among patients with chronic liver disease (CLD), the data are inconsistent on its prevalence and its relationship with CLD. This study aimed to estimate the prevalence of hypovitaminosis D among patients with CLD and to determine the relationship between hypovitaminosis D and severity of liver dysfunction, and calcium (Ca), phosphate (PO4) and parathyroid hormone (PTH) levels in CLD. Methods: The study included 236 CLD patients attending the Department of Hepatology, Rajiv Gandhi Government General Hospital (Chennai, India). Serum levels of 25-hydroxyvitamin D (25(OH)D), PTH, Ca, and PO4 were estimated. Severity of liver dysfunction was graded using the Child-Turcotte-Pugh (CTP) score. Results: The first report from our population showed that 162 of 236 (68.6%) CLD patients had hypovitaminosis D (25(OH)D levels of <30 ng/mL), with higher frequency (124/162) 76.5% among CTP B, C patients. Significant negative correlation (r = -0.288, p = 0.0001) between 25(OH)D and CTP scores was noted in hypovitaminosis D conditions. Level of 25(OH)D was correlated negatively with PTH (r = -0.537, p = 0.0001), positively with Ca (r = 0.657, p = 0.0001), and positively with PO4 (r = 0.477, p = 0.0001) in sufficient vitamin D conditions. Conclusions: Hypovitaminosis D is associated with higher CTP scores and is strongly associated with dysregulation of the Ca-PTH-vitamin D axis in CLD. Timely measurement of vitamin D levels is essential, along with levels of PTH, Ca and PO4, to manage CLD patients.

Changes in the microstructure of compact and trabecular bone tissues of mice subchronically exposed to alcohol

BACKGROUND

Alcohol is one of the most commonly consumed neurotoxins by humans. Its negative effect on bone health is known for a long time. However, its impact on qualitative and quantitative 2D characteristics of the compact bone is still unclear. Therefore, the aim of this study was to investigate in detail the effects of subchronic alcohol exposure on compact and trabecular bone tissues microstructure of laboratory mice using 2D and 3D imaging methods. Ten clinically healthy 12 weeks-old mice (males) were randomly divided into two groups. Animals from experimental group (group E; n = 5) drank a solution composed of 15% ethanol and water (1.7 g 100% ethanol kg-1 b.w. per day) for 8 weeks, while those from control group (group C; n = 5) drank only water.

RESULTS

Subchronic exposure to alcohol leads to several changes in qualitative 2D characteristics of the compact bone such as the presence of primary vascular radial bone tissue in pars anterior of endosteal border and a higher number of resorption lacunae (five times more) in the middle part of substantia compacta. Morphometrical 2D evaluations of the compact bone showed significantly increased sizes of primary osteons' vascular canals (p < 0.05) in mice from the experimental group (E group). Sizes of Haversian canals and secondary osteons were not affected by alcohol consumption. In mice from the E group, significantly lower values for relative bone volume and bone mineral density of the compact bone were observed. In the trabecular bone, decreased values for bone volume, trabecular number, trabecular thickness and bone surface (p < 0.05) were documented.

CONCLUSIONS

Alcohol decreased not only bone volume and density of the compact bone, but it also reduced trabecular bone volume and leads to trabecular thinning. It caused vasodilation of primary osteons' vascular canals and increased porosity in the compact bone.

Subacute exposure to alcohol in relation to bone microstructure of mice

Our study aimed to investigate subacute exposure to alcohol in relation to bone microstructure of mice. Animals from experimental (E) group drank a solution composed of 15 % ethanol and water for 14 days (one remodeling cycle), while those from control (C) group drank only water. In the compact bone of E group, decreased bone formation and increased porosity were observed which corresponds with lower levels of serum alkaline phosphatase and glutathione. Alcohol significantly increased sizes of primary osteon's vascular canals and decreased those of secondary osteons, Haversian canals. Relative bone volume, bone mineral density (BMD), relative bone volume without marrow cavity were also lower in E group. On the contrary, trabecular bone microstructure did not differ significantly between E and C groups. Liver function test showed higher levels of alanine aminotransferase, aspartate aminotransferase in alcohol-fed mice. Serum calcium, phosphate were significantly lower in E group. According to our study, only changes in compact bone microstructure of mice following one remodeling cycle were observed due to both direct and indirect effects of alcohol.

A study on OPG/RANK/RANKL axis in osteoporotic bile duct-ligated rats and the involvement of nitrergic and opioidergic systems

Chronic liver disease (CLD) affects millions of people and its impact on bone loss has become a subject of interest. Nitric oxide and endogenous opioids are suggested to increase during cholestasis/cirrhosis and may impact bone resorption by different mechanisms. The receptor activator of nuclear factor-κB (RANK)/RANK-ligand (RANKL)/osteoprotegerin (OPG) signaling pathway regulates bone resorption, but its role in metabolic bone disease subsequent to CLD is unknown. We aimed to investigate the involvement of nitrergic and opioidergic systems in bone loss relative to the RANK/RANKL/OPG pathway, in bile duct-ligated (BDL) rats. Eighty BDL/sham-operated (SO) rats received injections of 3 mg/kg/day Nω-Nitro-L-arginine methyl ester ± naltrexone (10 mg/kg/day) or saline for 28 days. Plasma bone turnover markers, OPG, RANK, and RANKL along with mRNA expression levels of the latter three were assessed. Plasma bone turnover markers and OPG level increased, but RANKL decreased in the BDL group compared with their SO controls (both: P ≤ 0.05). Administration of naltrexone reduced bone turnover markers and OPG level while increased RANKL content in comparison to BDL rats (P ≤ 0.05). As compared to untreated BDL rats, nitric oxide inhibition showed no effect on bone turnover marker i.e. OPG, RANK, and RANKL levels. BDL significantly increased RANK mRNA, but had no significant effect on RANKL and OPG mRNA expression. The lack of association between plasma levels and quantitative gene expression of RANKL and OPG suggests an indirect function of these markers in BDL rats. Considering that opioid receptor blockage by naltrexone in BDL animals caused a significant decrease in OPG and an increase in RANKL plasma contents, it could be postulated that the opioidergic system may have a regulatory effect on these bone markers.

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.

Diagnostic accuracy of the Coopscore© to predict liver fibrosis in human immunodeficiency virus/hepatitis B virus co-infection

Background Non-invasive methods for assessing liver fibrosis are increasingly used as an alternative to liver biopsy. Recently, a score-based biochemical blood test (Coopscore^©) was developed in a cohort of patients chronically infected with hepatitis C virus, showing higher diagnostic performances than Fibrometer®, Fibrotest®, Hepascore® and Fibroscan™. Here, we assess its performance in patients co-infected with the human immunodeficiency virus and hepatitis B virus. Methods Ninety-seven human immunodeficiency virus/hepatitis B virus co-infected patients with liver biopsies were included from a previously described cohort. Histological fibrosis staging using METAVIR criteria was used as the reference. Coopscore^©, Fibrotest®, Fibrometer®, Hepascore® and Zeng score were computed and compared with the Coopscore© using the Obuchowski index and area under the receiving operator characteristic curves. Results The distribution of liver fibrosis levels was as follows: F0-F1 ( n = 42), F2 ( n = 25), F3 ( n = 15) and F4 ( n = 15). The Obuchowski index was higher for Coopscore^© (0.774) than Fibrometer® (0.668), Hepascore® (0.690) and Zeng scores (0.704) ( P < 0.05), reflecting a better ability to discriminate between fibrosis stages. Similarly, when predicting significant fibrosis (≥F2), the AUROC was significantly greater for the Coopscore^© (0.836) than the Hepascore® (0.727) and Zeng scores (0.746), but not for the Fibrotest® (0.778, P = 0.14) or Fibrometer® (0.790, P = 0.19). The Coopscore^© did not show a higher capacity than other scores to predict advanced fibrosis (≥F3) or cirrhosis (F4). Conclusions This study supports the diagnostic value of the Coospcore^© in fibrosis staging among human immunodeficiency virus/hepatitis B virus co-infected patients, especially to predict significant fibrosis.

Concentrations of fetuin-A, osteoprotegerin and α-Klotho in patients with alcoholic liver cirrhosis

The aim of the present study was to evaluate the concentrations of fetuin-A, osteoprotegerin (OPG) and α-Klotho protein in patients with alcoholic cirrhosis at different stages of the disease, and to demonstrate that fetuin-A, osteoprotegin and α-Klotho may be used as markers of the severity of cirrhosis. A total of 54 patients with alcoholic liver cirrhosis treated in various hospitals in the Lublin region of Poland were randomly enrolled. The control group consisted of 18 healthy individuals without liver disease, who did not drink alcohol. Serum levels of fetuin-A, OPG and α-Klotho were measured by ELISA kits. Levels of fetuin-A were significantly reduced in patients with alcoholic liver cirrhosis compared with the control group. OPG levels were higher in patients with alcoholic liver cirrhosis than in the controls, whereas the levels of α-Klotho were comparable in the cirrhosis and control groups. No statistically significant differences in the concentrations of fetuin-A, OPG and α-Klotho protein were demonstrated according to type of liver cirrhosis. The findings of the present study revealed a significant negative correlation between the level of α-Klotho protein and C-reactive protein in the patients with alcoholic liver cirrhosis. Concentrations of fetuin-A were lower, whereas those of OPG were higher, in the alcoholic liver cirrhosis group compared with the control group. Fetuin-A, OPG and α-Klotho may not be good indicators of liver cirrhosis severity. In conclusion, fetuin-A and OPG may be used in the diagnosis of liver cirrhosis.

Osteoprotegerin Levels Decrease in Abstinent Alcohol-Dependent Patients

BACKGROUND

Osteoprotegerin (OPG) is a parameter of increasing interest in the search for pathophysiological mechanisms of reduced bone mineral density (BMD). It has been shown to be increased in alcohol-dependent subjects. In our study, we wanted to examine whether changes in OPG and receptor activator of the nuclear factor-κB ligand (RANKL) levels during an 8-week abstinence period in alcohol-dependent patients treated in an alcohol rehabilitation clinic would occur and whether alcohol-related variables, smoking, status, or physical activity prior to the study served as an influence on BMD and on OPG/RANKL levels.

METHODS

Forty-three patients, who were abstinent not longer than a week, were included in the study. OPG and RANKL as well as other markers of bone metabolism were measured at baseline, and after 8 weeks of treatment, BMD was measured once.

RESULTS

OPG levels decreased significantly, while osteocalcin, a marker of bone formation, increased significantly. RANKL as well as RANKL/OPG ratio, Serum CrossLaps, and all examined hormones showed no significant changes over time. Inflammatory parameters showed a significant reduction after 8 weeks. We detected no influence of potentially confounding variables of alcohol dependency on the course of OPG or other laboratory values.

CONCLUSIONS

Our results could point to the well-known risk for reduced BMD in these patients being reversible with abstinence through an excess of bone formation. We also confirmed earlier findings that inflammatory processes play a role in the pathogenesis of alcohol-induced disturbances in bone metabolism.

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.

Bone changes in alcoholic liver disease

Alcoholism has been associated with growth impairment, osteomalacia, delayed fracture healing, and aseptic necrosis (primarily necrosis of the femoral head), but the main alterations observed in the bones of alcoholic patients are osteoporosis and an increased risk of fractures. Decreased bone mass is a hallmark of osteoporosis, and it may be due either to decreased bone synthesis and/or to increased bone breakdown. Ethanol may affect both mechanisms. It is generally accepted that ethanol decreases bone synthesis, and most authors have reported decreased osteocalcin levels (a “marker” of bone synthesis), but some controversy exists regarding the effect of alcohol on bone breakdown, and, indeed, disparate results have been reported for telopeptide and other biochemical markers of bone resorption. In addition to the direct effect of ethanol, systemic alterations such as malnutrition, malabsorption, liver disease, increased levels of proinflammatory cytokines, alcoholic myopathy and neuropathy, low testosterone levels, and an increased risk of trauma, play contributory roles. The treatment of alcoholic bone disease should be aimed towards increasing bone formation and decreasing bone degradation. In this sense, vitamin D and calcium supplementation, together with biphosphonates are essential, but alcohol abstinence and nutritional improvement are equally important. In this review we study the pathogenesis of bone changes in alcoholic liver disease and discuss potential therapies.

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.

Bone alterations in hepatitis C virus infected patients

BACKGROUND AND AIMS

Most studies have shown that patients with chronic hepatitis C virus (HCV) infection are affected by osteoporosis. However, liver function impairment and deranged nutrition may both play a role in the bone alterations observed. In some works no osteoporosis was found, and some cases of osteosclerosis have been reported. The aim of the study is to assess bone alterations in treatment-naïve, well-nourished HCV patients, in order to discern whether or not HCV infection causes osteoporosis.

METHODS

Whole-body bone densitometry and assessment of T-score at lumbar spine and hip were performed to 40 patients and 40 age- and sex-matched controls, with a Lunar Prodigy Advance (General Electric, Piscataway, NJ, USA). All the patients underwent liver biopsy. Nutritional evaluation was performed by subjective nutritional assessment, body mass index (BMI), and densitometric assessment of total lean mass and total fat mass. Serum osteocalcin, osteoprotegerin, RANKL, PTH, crosslaps, vitamin D3, testosterone, IGF-1, and estradiol were determined.

RESULTS

Patients did not show differences in total bone mineral density (BMD) or T-score with controls. On the contrary, about a third of them showed positive T scores. Patients showed lower IGF-1, vitamin D3 and testosterone, but higher telopeptide levels, and a trend to higher osteoprotegerin levels. Multivariate analyses disclosed that age, sex, and total lean mass were the only parameters independently related with BMD.

CONCLUSIONS

Therefore, chronic HCV infection in well nourished patients with preserved liver function does not cause osteoporosis.

Osteoporosis in chronic liver disease

Osteoporosis is a common skeletal complication seen in patients with chronic liver disease. Osteoporosis is usually asymptomatic and, if untreated, can result in fractures and impaired quality of life. For this review, we performed a systematic search of the PubMed database, and all recent peer-reviewed articles regarding the prevalence, pathophysiology, diagnosis, and management of osteoporosis in chronic liver disease were included. The prevalence of osteoporosis varies between 11% and 58% in patients with chronic liver disease and in transplant recipients. The etiology of osteoporosis is multifactorial and only partially understood. Various factors linked to the pathogenesis of bone loss are vitamin D, calcium, insulin growth factor-1, receptor activation of nuclear factor-κB ligand (RANKL), bilirubin, fibronectin, leptin, proinflammatory cytokines, and genetic polymorphisms. Management of osteoporosis involves early diagnosis, identifying and minimizing risk factors, general supportive care, nutrition therapy, and pharmacotherapy. Osteoporosis is diagnosed based on the bone mineral density (BMD) assessment using dual-energy X-ray absorptiometry scan. Measurement of BMD should be considered in all patients with advanced liver disease and in transplant recipients. Vitamin D and calcium supplementation is recommended for all patients with osteoporosis. Specific agents used for treatment of osteoporosis include bisphosphonates, calcitonin, hormonal therapy, and raloxifene. Bisphosphonates have become the mainstay of therapy for osteoporosis prevention and treatment. Prolonged suppression of bone remodeling resulting in atypical fractures has emerged as a significant complication with long-term use of bisphosphonates. Newer treatment agents and better fracture prevention strategies are necessary to prevent and treat osteoporosis.

Including osteoprotegerin and collagen IV in a score-based blood test for liver fibrosis increases diagnostic accuracy

BACKGROUND

Noninvasive methods for liver fibrosis evaluation in chronic liver diseases have been recently developed, i.e. transient elastography (Fibroscan™) and blood tests (Fibrometer®, Fibrotest®, and Hepascore®). In this study, we aimed to design a new score in chronic hepatitis C (CHC) by selecting blood markers in a large panel and we compared its diagnostic performance with those of other noninvasive methods.

METHODS

Sixteen blood tests were performed in 306 untreated CHC patients included in a multicenter prospective study (ANRS HC EP 23 Fibrostar) using METAVIR histological fibrosis stage as reference. The new score was constructed by non linear regression using the most accurate biomarkers.

RESULTS

Five markers (alpha-2-macroglobulin, apolipoprotein-A1, AST, collagen IV and osteoprotegerin) were included in the new function called Coopscore©. Using the Obuchowski Index, Coopscore© shows higher diagnostic performances than for Fibrometer®, Fibrotest®, Hepascore® and Fibroscan™ in CHC. Association between Fibroscan™ and Coopscore© might avoid 68% of liver biopsies for the diagnosis of significant fibrosis.

CONCLUSION

Coopscore© provides higher accuracy than other noninvasive methods for the diagnosis of liver fibrosis in CHC. The association of Coopscore© with Fibroscan™ increases its predictive value.

Hepatic osteodystrophy: An important matter for consideration in chronic liver disease

Hepatic osteodystrophy (HO) is the generic term defining the group of alterations in bone mineral metabolism found in patients with chronic liver disease. This paper is a global review of HO and its main pathophysiological, epidemiological and therapeutic aspects. Studies examining the most relevant information concerning the prevalence, etiological factors, diagnostic and therapeutic aspects involved in HO were identified by a systematic literature search of the PubMed database. HO generically defines overall alterations in bone mineral density (BMD) (osteoporosis or osteopenia) which appear as a possible complication of chronic liver disease. The origin of HO is multifactorial and its etiology and severity vary in accordance with the underlying liver disease. Its exact prevalence is unknown, but different studies estimate that it could affect from 20% to 50% of patients. The reported mean prevalence of osteoporosis ranges from 13%-60% in chronic cholestasis to 20% in chronic viral hepatitis and 55% in viral cirrhosis. Alcoholic liver disease is not always related to osteopenia. HO has been commonly studied in chronic cholestatic disease (primary biliary cirrhosis and primary sclerosing cholangitis). Several risk factors and pathogenic mechanisms have been associated with the loss of BMD in patients with chronic liver disease. However, little information has been discovered in relationship to most of these mechanisms. Screening for osteopenia and osteoporosis is recommended in advanced chronic liver disease. There is a lack of randomized studies assessing specific management for HO.

Bone mineral density assessed by dual-energy X-ray absorptiometry in patients with viral or alcoholic compensated cirrhosis. A prospective study

BACKGROUND/AIM

Cirrhosis is considered as a risk factor for osteoporosis whose prevalence is poorly known. The aim was to assess prospectively bone mineral density (BMD) in patients with alcoholic or viral compensated cirrhosis.

METHODS

From 2006 to 2008, patients with viral or alcoholic compensated cirrhosis had BMD assessment by dual-energy X-ray absorptiometry. The prevalence of osteopenia (-2.5SD <T-score<-1SD) and osteoporosis (T-score ≤-2.5SD), and the influence of age, gender and aetiology of cirrhosis were assessed using univariate and multiple regression analysis.

RESULTS

One hundred and nine patients were studied (72 men, 55.3 ± 11.4 years and 37 women, 65.2 ± 11.0); with HBV (n=35), HCV (n=43), or alcoholic cirrhosis (n=31). At the lumbar spine, 25 patients had osteopenia and 12 had osteoporosis. At the femoral site, 23 had osteopenia and 4 had osteoporosis. Female gender had an independent decreased effect on the total BMD.

CONCLUSIONS

The prevalence of osteoporosis was up to 11% at the lumbar spine, greater in women independently of age, without significant difference according to the aetiology of cirrhosis.

Bone mineral density, bone turnover markers and cytokines in alcohol-induced cirrhosis

AIMS

Liver cirrhosis is a risk factor for osteoporosis. However, the pathogenesis of the bone mass loss in patients with alcohol-induced cirrhosis (AC) is not well understood. Serum concentrations of soluble tumour necrosis factor receptor (sTNF-R55), neopterin and soluble interleukin 2 receptor (sIL-2R), activation markers of cellular immunity, correlate with clinical activity and severity of the AC. The aim of this study is to evaluate the association of these soluble markers with the development of osteoporosis in patients with AC.

METHODS

We studied 33 consecutive patients with AC and 24 healthy volunteers. Bone mineral density (BMD) was measured by X-ray absorptiometry in the lumbar spine (LS) and femoral neck (FN). Neopterin was measured by radioimmunoassay. Serum concentrations of sTNF-R55 and sIL-2R were measured by enzyme immunoassay. We also determined serum levels of osteocalcin and bone alkaline phosphatase as biochemical markers of bone formation, and deoxypyridinoline urinary excretion (D-Pyr) as marker of bone resorption.

RESULTS

Patients with AC had reduced BMD (expressed as z-score) in all sites (LS: P < 0.001 and FN: P < 0.05). Serum concentrations of sTNF-R55 were significantly higher in patients with both AC and osteoporosis than in those with only AC (P < 0.001). Serum levels of sTNF-R55 positively correlated with D-Pyr urinary excretion (r = 0.354; P = 0.01). Serum levels of sIL-2R were significantly higher in patients with both AC and osteoporosis than in those with only AC (P < 0.05).

CONCLUSIONS

There is a relation between activation of the cellular immunity and osteoporosis in AC. Bone mass loss could be related to the increased bone resorption found in these patients.

Prognosis of osteopenia in chronic alcoholics

Osteoporosis is frequent among alcoholics all by a direct effect of ethanol, malnutrition, and liver failure. Therefore, it may be related to survival. The aim of this study was to assess bone mineral density (BMD), bone mineral content, hormonal status, and to determine prognostic value of these parameters in a total of 124 alcoholics followed up for a median period of 57 months. Several bone homeostasis-related hormones were measured in patients and age- and sex-matched controls. Whole-body densitometry was performed by a Hologic QDR-2000 (Waltham, MA) densitometer; nutritional status and liver function were assessed. Sixty patients underwent a second evaluation 6 months later. Patients showed lower serum insulin-like growth factor-1 (median=58, interquartile range [IQR]=33-135 vs. 135ng/mL, IQR=116-243ng/mL, P<.001), vitamin D (25.5, IQR=18.3-36.8 vs. 79.9pg/mL, IQR=59.2-107.8pg/mL, P<.001), and osteocalcin (2.1, IQR=1.1-4.5 vs. 6.5ng/mL, IQR=4.7-8.7ng/mL, P<.001) than controls, and lower BMD values, and lower Z- and T-scores at right and left legs and arms, thoracic and lumbar spine, pelvis, and right and left ribs. By multiple regression analysis, BMD mainly depends on nutritional parameters and liver function. Kaplan-Meier curves show that subtotal BMD and BMD at both arms and pelvis were significantly related with survival. Patients who had lost total hip BMD after 6 months showed a shorter survival than those who had not, but using Cox's regression, encephalopathy, ascites, and nutritional parameters displaced BMD as prognostic factor. Therefore, osteopenia ensues in chronic alcoholic patients. It mainly depends on poor nutrition and is related to survival, although surpassed in this sense by encephalopathy, ascites, and nutritional parameters.

Vitamin D and nutritional status are related to bone fractures in alcoholics

BACKGROUND

Bone fractures are common in alcoholics.

AIMS

To analyse which factors (ethanol consumption; liver function impairment; bone densitometry; hormone changes; nutritional status, and disrupted social links and altered eating habits) are related to bone fractures in 90 alcoholic men admitted to our hospitalization unit because of organic problems.

METHODS

Bone homoeostasis-related hormones were measured in patients and age- and sex-matched controls. Whole-body densitometry was performed by a Hologic QDR-2000 (Waltham, MA, USA) densitometer, recording bone mineral density (BMD) and fat and lean mass; nutritional status and liver function were assessed. The presence of prevalent fractures was assessed by anamnesis and chest X-ray film.

RESULTS

Forty-nine patients presented at least one fracture. We failed to find differences between patients with and without fractures regarding BMD parameters. Differences regarding fat mass were absent, but lean mass was lower among patients with bone fracture. The presence of fracture was significantly associated with impaired subjective nutritional evaluation (χ² = 5.79, P = 0.016), lower vitamin D levels (Z = 2.98, P = 0.003) and irregular eating habits (χ² = 5.32, P = 0.02). Reduced lean mass and fat mass, and altered eating habits were more prevalent among patients with only rib fractures (n = 36) than in patients with multiple fractures and/or fractures affecting other bones (n = 13). These last were more closely related to decompensated liver disease. Serum vitamin D levels showed a significant relationship with handgrip strength (ρ = 0.26, P = 0.023) and lean mass at different parts of the body, but not with fat mass. By logistic regression analysis, only vitamin D and subjective nutritional evaluation were significantly, independently related with fractures.

CONCLUSION

Prevalent fractures are common among heavy alcoholics. Their presence is related more closely to nutritional status, lean mass and vitamin D levels than to BMD. Lean mass is more reduced, nutritional status is more impaired and there is a trend to more altered eating habits among patients with rib fractures, whereas multiple fractures depend more heavily on advanced liver disease.

Serum levels of osteoprotegerin in the spectrum of nonalcoholic fatty liver disease

OBJECTIVE

Osteoprotegerin (OPG) is a member of the tumor necrosis factor superfamily with pleiotropic effects on inflammation, endocrine function and the immune system. Reduced OPG levels are related to insulin resistance. We tested the hypothesis that serum levels of OPG may be associated with nonalcoholic fatty liver disease (NAFLD).

MATERIAL AND METHODS

Four groups of patients were enrolled in the present study: subjects with definite nonalcoholic steatohepatitis (NASH, n = 56), borderline NASH (n = 26), simple fatty liver (n = 17) and healthy controls without evidence of liver disease (n = 58). Serum levels of OPG were measured by ELISA.

RESULTS

Concentrations of OPG were significantly lower in patients with definite NASH (median: 45 pg/mL, p < 0.001) and borderline NASH (57 pg/mL, p < 0.001) than in controls (92 pg/mL). The area under the ROC curve for distinguishing between steatohepatitis (definite NASH plus borderline NASH) and healthy controls using OPG was 0.82. The use of a cut-off level < 74 pg/mL for serum OPG levels yielded sensitivity and specificity values of 75.6% and 75.9%, respectively.

CONCLUSIONS

Serum osteoprotegerin concentrations are reduced in patients with the more severe forms of NAFLD and may serve as a noninvasive biomarker to identify patients with NASH.

RANKL inhibition for the management of patients with benign metabolic bone disorders

The receptor activator of NF-kappaB ligand (RANKL) is a member of the TNF receptor superfamily, essential for osteoclastogenesis. It binds to its receptor activator of NF-kappaB on the surface of osteoclast precursors and enhances their differentiation, survival and fusion, while it activates mature osteoclasts and inhibits their apoptosis. The effects of RANKL are counteracted by osteoprotegerin (OPG), a neutralizing decoy receptor. Derangement of the balance in RANKL/OPG action is implicated in the pathophysiology of metabolic bone diseases, including osteoporosis. Current therapies used to prevent or treat metabolic bone diseases are thought to act, at least in part, through modification of the RANKL/OPG dipole. The idea of using a molecule that could specifically bind and neutralize RANKL to decrease bone resorption and subsequent bone loss is appealing. Recombinant OPG was initially tested. Denosumab, a fully human monoclonal antibody against RANKL, is a promising antiresorptive agent under investigation. It rapidly decreases bone turnover markers resulting in a significant increase in bone mineral density and reduction in fracture risk. However, because receptor activator of NF-kappaB activation by RANKL is also essential for T-cell growth and dendritic-cell function, inhibition of its action could simultaneously affect the immune system, leading to susceptibility in infections or malignancies.

Current understanding of osteoporosis associated with liver disease

Osteoporosis is a common complication of many types of liver disease. Research into the pathogenesis of osteoporosis has revealed that the mechanisms of bone loss differ between different types of liver disease. This Review summarizes our current understanding of osteoporosis associated with liver disease and the new advances that have been made in this field. The different mechanisms by which cholestatic and parenchymal liver disease can lead to reduced bone mass, the prevalence of osteopenia and osteoporosis in patients with early and advanced liver disease, and the influence of osteoporotic fractures on patient survival are discussed along with the advances in our understanding of the molecular pathways associated with bone loss. The role of the CSF1-RANKL system and that of the liver molecule, oncofetal fibronectin, a protein that has traditionally been viewed as an extracellular matrix protein are also discussed. The potential impact that these advances may have for the treatment of osteoporosis associated with liver disease is also reviewed.

Total serum testosterone estimation and ultrasonographic volumetric evaluation of testes in patients with alcoholic liver cirrhosis

In the course of cirrhosis, a variety of disturbances of endocrine glands occur. Degenerative changes in the testes with atrophia and fibrosis of the glandular tissue are often found in men. Twenty-one males with compensated alcoholic liver cirrhosis were studied. The age ranged from 29 to 61 years (mean 47,1). Efficiency of the liver was evaluated according to Child classification. HBC (this needs to be spelled out in parenthesis) or HBV (Hepatitis B Virus) infections were excluded. Levels of serum testosterone were determined and the volume size of the testes was measured using 7,5 MHz sector probe, B&K Medical ultrasonograph, 3535 model. Volume size of the testes was measured in 22 healthy control volunteers, as well; age ranged from 25 to 66 years (mean-46,6). All patients were interviewed about sexual function, particularly possible erectile dysfunction using IIEF-5 questionnaire. The mean testosterone level was 8,89 umol/l (ranged: 7,4–10,9 umol/l) in the study patients [the normal range interval: 8,2–34,6 umol/l]. The level was below the normal range in 4 patients, and low but within the normal range in the remaining patients. Statistically significant lower values of both testes volumes were estimated in patients with compensated alcoholic liver cirrhosis in comparison to healthy controls (p<0,001), however only 5 (23,81 %) study group subjects admitted impaired libido and erectile dysfunction. Decreased levels of testosterone in the peripheral blood and diminished volume size of testes are found in patients suffering from alcoholic liver cirrhosis. Erectile dysfunction in patients with liver cirrhosis needs further evaluation.

Cholestasis and metabolic bone disease - a clinical review

Metabolic bone disease, mainly osteopenia/osteoporosis and occasionally osteomalacia, is a major extrahepatic manifestation of chronic cholestatic liver disease (synonym: hepatic osteodystrophy). Reduced bone mineral density is found in up to 60% and atraumatic fractures in about 20% of patients with chronic liver disease. Hepatic osteodystrophy is characterized by reduced formation and increased resorption of bone; major risk factors are chronic cholestasis and advanced cirrhosis. Pathogenetic mechanisms include genetic factors, abnormalities of calcium, vitamin D, vitamin K and bilirubin metabolism, IGF-1 deficiency, the RANKL/OPG-system, hypogonadism, drugs harmful to bone, lifestyle factors (smoking, alcoholism, immobility), malnutrition and low body mass index. Screening for osteopenia should be performed and reversible risk factors must be corrected. At present, bisphosphonates are the predominantly used specific drugs for the treatment of osteoporosis in chronic liver disease. After orthotopic liver transplantation bone mineral density improves in long-term follow-up. Studies are needed for fracture prevention in chronic liver disease.

Osteopenia in alcoholics: effect of alcohol abstinence

AIMS

The aims of this study were to assess bone mineral density (BMD) and content (BMC), osteocalcin, serum telopeptide, PTH and vitamin D in alcoholics, and to determine if a 6-month period of abstinence leads to changes in these parameters.

METHODS

Serum osteocalcin, insulin-like growth factor 1 (IGF-1), telopeptide (40 patients) and 1,25 dihydroxyvitamin D, were measured in 28 controls and 77 alcoholic patients, 48 of whom were evaluated again 6 months later. All patients underwent whole-body assessment of BMD by a Hologic QDR-2000 (Waltham, MA, USA) bone densitometer, at the beginning of the study and 6 months later.

RESULTS

Patients showed higher serum telopeptide levels (0.59 +/- 0.40 versus 0.19 +/- 0.10 nmol/100 ml, P < 0.001), lower IGF-1 [median = 49, interquartile range (IQR) = 31-121 ng/ml versus 135, IQR = 116-237 ng/ml, P < 0.001], vitamin D [26.5, IQR = 17.0-37.8 pg/ml versus 82.4 (IQR = 60.9-107.4 pg/ml, P < 0.001] and osteocalcin (2.1, IQR = 1.1-3.6 ng/ml versus 6.65, IQR = 4.9-8.8 ng/ml, P < 0.001) than those in controls. Patients also showed lower BMD values, Z- and T-scores at many levels of the skeleton and reduced total BMC. After 6 months, those who continued drinking showed a loss of bone mass, whereas those who abstained showed either no change or increase, differences being especially marked at pelvis, right arm and total BMD and BMC. Simultaneously, abstainers showed a significant increase in osteocalcin (versus a decrease among those who continued drinking). Serum telopeptide increased in both groups.

CONCLUSION

Ethanol consumption leads to osteopenia, and decreased serum osteocalcin, which improve with abstinence, whereas those who continue drinking show a worsening of both parameters.

Relationships between OPG, RANKL, bone metabolism, and bone mineral density in biliary atresia

PURPOSE

Osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) have been implicated in osteoclastogenesis. However, the relationship between the OPG-RANKL system and bone status in biliary atresia (BA) has not, as yet, been clarified. Thus, the aim of this study has been to evaluate the relationship between the OPG-RANKL system and bone mineral metabolism in patients with BA.

METHODS

Fifty patients with BA and 13 healthy controls were investigated. The mean age of BA patients and controls was 7.3 +/- 0.6 and 8.0 +/- 1.1 years, respectively. Serum levels of OPG, RANKL, osteocalcin, and C-terminal telopeptide of type I collagen (CTX) were measured by sandwich enzyme-linked immunosorbent assay. Bone mineral density (BMD) of the lumbar spine was determined by dual energy X-ray absorptiometry.

RESULTS

Biliary atresia patients had significantly elevated serum OPG levels compared with controls (4.0 +/- 0.3 vs. 3.0 +/- 0.3 pmol/L, P = 0.02) and serum OPG levels in BA patients with jaundice were higher than in those without jaundice (4.6 +/- 0.4 vs. 3.6 +/- 0.4 pmol/L, P = 0.04). Likewise, serum RANKL levels were significantly higher in BA patients than in controls (2.9 +/- 0.2 vs. 1.2 +/- 0.7 pmol/L, P = 0.001). In addition, serum RANKL levels were increased in BA patients with jaundice compared to those without jaundice, but this difference was not statistically significant (3.2 +/- 0.3 vs. 2.7 +/- 0.2 pmol/L, P = 0.2). The serum osteocalcin levels in BA patients were not significantly different from those in the healthy controls, whereas the serum CTX levels were elevated in BA patients compared with the controls (0.4 +/- 0.1 vs. 0.2 +/- 0.1 ng/mL, P = 0.02). Furthermore, BMD of BA children with jaundice was significantly lower than that of BA children without jaundice (P = 0.0005). BMD of BA patients was inversely correlated with serum levels of OPG (r = -0.452, P < 0.001).

CONCLUSION

Elevated serum OPG levels are associated with reduced BMD and the outcome of BA. The increase of serum OPG in BA patients with severe disease could reflect a compensatory response to bone loss.

Reduced duodenal cytochrome P450 3A protein expression and catalytic activity in patients with cirrhosis

The small intestine and liver express high levels of cytochrome P450 3A (CYP3A), an enzyme subfamily that contributes significantly to drug metabolism. In patients with cirrhosis, reduced metabolism of drugs is typically attributed to decreased liver function, but it is unclear whether drug metabolism in the intestine is also compromised. In this study, we compared CYP3A protein expression and in vitro midazolam hydroxylation in duodenal mucosal biopsies from subjects with normal liver function (controls; n = 20) and subjects with various levels of severity of cirrhosis (n = 23). In samples from subjects with cirrhosis, duodenal CYP3A expression and total midazolam hydroxylation were lower by 47 and 34%, respectively, as compared with samples from controls. Greater decreases in CYP3A expression were seen in subjects with more severe cirrhosis. Therefore, patients with advanced cirrhosis may have greater drug exposure following oral dosing as a result of both impaired liver function and decreased intestinal CYP3A expression and activity.

High osteoprotegerin serum levels in primary biliary cirrhosis are associated with disease severity but not with the mRNA gene expression in liver tissue

The influence of osteoprotegerin and RANKL as regulators of osteoclastogenesis and bone remodeling in liver disease and in the development of osteoporosis in primary biliary cirrhosis (PBC) is uncertain. Therefore, 68 women with PBC and 20 healthy females were studied by assessing circulating osteoprotegerin and RANKL. Bone mineral density and markers of bone turnover were measured as well. Osteoprotegerin-mRNA expression was also assessed in liver tissue from 16 patients and 5 controls. Osteoprotegerin was higher in PBC than in controls (5.4 +/- 0.2 vs. 2.9 +/- 0.2 pM/l, P < 0.0001), whilst RANKL was lower in patients than in controls (0.39 +/- 0.06 vs. 1.40 +/- 0.16 pM/l, P < 0.0001). Osteoprotegerin was more elevated in patients with more advanced disease, as defined by bilirubin above 1.2 mg/dl (6.6 +/- 0.6 vs. 5.2 +/- 0.2 pM/l, P = 0.02) or by Mayo over 4 (5.9 +/- 0.3 vs. 4.8 +/- 0.2 pM/l, P = 0.02). Osteoprotegerin and RANKL were unrelated with osteoporosis, and no associations were found with markers of bone remodeling, except for RANKL, which was particularly decreased in patients with low osteocalcin. This marker of bone formation was also higher in patients with elevated circulating osteoprotegerin. Liver osteoprotegerin gene expression was similar in patients and controls, and no correlation was found between liver osteoprotegerin-mRNA and patients' respective circulating levels. In conclusion, osteoprotegerin and RANKL are abnormal in patients with PBC, regardless of osteoporosis. The elevated circulating osteoprotegerin is associated with the severity of disease, but not with gene expression in the liver.

Skeletal turnover, bone mineral density, and fractures in male chronic abusers of alcohol

BACKGROUND

Chronic alcohol abuse is a risk factor for osteoporosis and fractures, whose pathogenesis is still unclear. We investigated the influence of alcoholism and other risk factors on calcium and skeletal metabolism, bone mineral density (BMD), and fractures.

MATERIALS AND METHODS

In 51 chronic male alcoholics without liver failure and 31 healthy controls, serum total and ionised calcium, phosphate, creatinine, 25-hydroxy vitamin D (25OHD), PTH, total (ALP) and bone-specific (BALP) alkaline phosphatase, osteocalcin (BGP), carboxy-terminal telopeptide of type I collagen (beta-CTx), osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) were assessed. In patients only, we also measured serum testosterone, 17-beta estradiol, LH, and IGF-I. BMD was measured by dual energy x-ray absorptiometry at lumbar spine (LS-) and femur [neck (FN-) and total hip (TF-)]. Vertebral fractures were identified by a semiquantitative method on thoraco-lumbar spine x-ray, non-vertebral fractures (as life-style factors) by history.

RESULTS

Alcoholics were leaner, had significantly higher ALP and BALP, and lower BGP and 25OHD levels than controls. No significant difference in other calcium and bone metabolism parameters was found. OPG/RANKL ratio was significantly higher in alcoholics. Beta-CTx negatively correlated with abuse duration. OPG positively correlated with daily alcohol assumption and with indexes of liver cytolysis. Though LS-, FN- and TF-BMD of alcoholics and controls did not significantly differ, patients had a much higher prevalence of vertebral fractures. The same was found considering both vertebral and non-vertebral fractures.

CONCLUSIONS

Ethanol-induced skeletal damage seems mainly dependent on negative effects on bone formation. Lifestyle factors and traumas likely contribute to the high fracture incidence of alcohol abusers, independently of BMD.

Osteoporosis in celiac disease and in endocrine and reproductive disorders

As the increase in lifespan brings to light diseases that were previously not clinically detectable, osteoporosis has become an issue of worldwide significance. The disease is marked by a loss of bone mass; the bones become less dense, fragile and more prone to fracturing. Because it is regulated by endocrine and environmental factors, osteoporosis presents a multifactorial etiopathogenesis, with the genetic component accounting for 70% of an individual variation in bone mass density (BMD), the principal determinant, with age, of fracture risk. Pathological conditions such as celiac disease (CD) exacerbate the process of bone loss, so that the occurrence of osteoporosis in celiac subjects is of particular note: indeed, the screening of osteoporosis patients for this disease is advisable, since it may be the only sign of undiagnosed CD. An increase in interleukin IL-1β, of the IL-1 system, in the relatives of celiac patients confirms the genetic predisposition to osteoporosis and its presence is evidence of an association between the two conditions. The direct effect on the bones of CD is secondary to poor absorption of calcium and vitamin D. In women osteoporosis is indirectly associated with early menopause and amenorrhea, and it may follow prolonged breast-feeding and frequent pregnancies, while in men it is associated with hypogonadism and GH deficit. These endocrine and non-endocrine factors exert their effects on bones by modulating the RANK/RANK-L/OPG system. An appropriate lifestyle from adolescence onwards, together with early diagnosis of and treatment for CD and primary and secondary endocrine pathologies are important for the prevention of damage to the bones.

Serum osteoprotegerin and its ligand in cirrhotic patients referred for orthotopic liver transplantation: relationship with metabolic bone disease

AIMS

A prospective study was carried out in 22 cirrhotic patients referred for orthotopic liver transplantation, in order to analyze serum osteoprotegerin (OPG) and RANKL levels and their relationship with metabolic bone disease.

METHODS

Serum levels of OPG and RANKL were measured in all patients as well as bone markers, serum parathyroid hormone and 25-hydroxyvitamin D levels. OPG and RANKL values were compared with those obtained in 29 healthy controls. Bone mineral density (BMD) of the lumbar spine and proximal femur was measured by dual X-ray absorptiometry and spinal X-rays were obtained to assess vertebral fractures.

RESULTS

Serum OPG levels were higher in cirrhotic patients than in controls (6.4+/-2 vs 2.7+/-0.7 pmol/l; P=0.001) and RANKL serum levels were lower in cirrhotic patients (0.215+/-0.6 vs 1.012+/-1.2 pmol/l; P=0.002), with an increased OPG:RANKL ratio when compared with the control group (280.3+/-334.5 vs 113+/-137.6; P=0.04). Ten patients had osteoporosis (45%) and up to 45% skeletal fractures. No differences were found in OPG levels between patients with and without osteoporosis by densitometric criteria or fractures. Negative correlations were found between OPG levels and femoral neck (R-0.46; P=0.03) and total hip BMD (R-0.48; P=0.025). By contrast, OPG values were not related to markers of bone turnover.

CONCLUSIONS

OPG values are elevated in cirrhotic patients before liver transplantation, particularly in those with low bone mass at the proximal femur.

Vitamin D and parathyroid hormone in outpatients with noncholestatic chronic liver disease

BACKGROUND & AIMS

The liver plays a central role in vitamin D metabolism. Our aim was to determine the prevalence and type of vitamin D-parathyroid hormone (PTH) disturbance in ambulatory patients with noncholestatic chronic liver disease (CLD) and its relationship with disease severity and liver function.

METHODS

We studied 100 consecutive outpatients (63 men, 37 women; mean age, 49.0 +/- 12.1 [SD] y) with noncholestatic CLD caused by alcohol (n = 40), hepatitis C (n = 38), hepatitis B (n = 12), autoimmune hepatitis (n = 4), hemochromatosis (n = 4), and nonalcoholic steatohepatitis (n = 2); 51 patients had cirrhosis. Serum concentrations of 25-hydroxyvitamin D (25[OH]D), PTH, calcium, phosphate, magnesium, creatinine, and liver function tests were determined.

RESULTS

Serum 25(OH)D levels were inadequate in 91 patients: vitamin D deficiency (<50 nmol/L) was found in 68 patients and vitamin D insufficiency (50-80 nmol/L) was found in 23 patients. Secondary hyperparathyroidism (serum PTH, >6.8 pmol/L) was present in 16 patients. The prevalence of vitamin D deficiency was significantly higher in cirrhotic vs noncirrhotic patients (86.3% vs 49.0%; P = .0001). In Child-Pugh class C patients, 25(OH)D levels were significantly lower than in class A patients (22.7 +/- 10.0 nmol/L vs 45.8 +/- 16.8 nmol/L; P < .001). Serum 25(OH)D independently correlated with international normalized ratio (negatively; P = .018) and serum albumin (positively; P = .007). Serum 25(OH)D levels of less than 25 nmol/L predicted coagulopathy, hyperbilirubinemia, hypoalbuminemia, increased alkaline phosphatase, and anemia and thrombocytopenia.

CONCLUSIONS

Vitamin D inadequacy is common in noncholestatic CLD and correlates with disease severity, but secondary hyperparathyroidism is relatively infrequent. Management of CLD should include assessment of vitamin D status in all patients and replacement when necessary.