Bone loss and reduced osteoblast function in primary biliary cirrhosis

Prevalence and risk factors of osteoporosis detected by dual-energy X-ray absorptiometry among Chinese patients with primary biliary cholangitis

BACKGROUND

Osteoporosis is an extrahepatic complication of primary biliary cholangitis (PBC) that increases the risk of fractures and mortality. However, Epidemiological studies of osteoporosis in patients with PBC in China and the Asia-Pacific region is lack.

AIM

To assess the prevalence and clinical characteristics of osteoporosis in Chinese patients with PBC.

METHODS

This retrospective analysis included consecutive patients with PBC from a tertiary care center in China who underwent bone mineral density (BMD) assessment using dual-energy X-ray absorptiometry between January 2013 and December 2021. We defined subjects with T-scores ≤ -2.5 in any sites (L1 to L4, femoral neck, or total hip) as having osteoporosis. Demographic, serological, clinical, and histological data were collected. Independent risk factors for osteoporosis were identified by multivariate logistic regression analysis.

RESULTS

A total of 268 patients with PBC [236 women (88.1%); mean age, 56.7 ± 10.6 years; 163 liver biopsies (60.8%)] were included. The overall prevalence of osteoporosis in patients with PBC was 45.5% (122/268), with the prevalence of osteoporosis in women and men being 47.0% and 34.4%, respectively. The prevalence of osteoporosis in postmenopausal women was significantly higher than that in premenopausal women (56.3% vs 21.0%, P < 0.001). Osteoporosis in patients with PBC is associated with age, fatigue, menopausal status, previous steroid therapy, body mass index (BMI), splenomegaly, gastroesophageal varices, ascites, Mayo risk score, histological stage, alanine aminotransferase, albumin, bilirubin, platelet and prothrombin activity. Multivariate regression analysis identified that older age, lower BMI, previous steroid therapy, higher Mayo risk score, and advanced histological stage as the main independent risk factors for osteoporosis in PBC.

CONCLUSION

Osteoporosis is very common in Chinese patients with PBC, allowing for prior screening of BMD in those PBC patients with older age, lower BMI, previous steroid therapy and advanced liver disease.

Role of hormones in bone remodeling in the craniofacial complex: A review

Background

Diseases such as periodontitis and osteoporosis are expected to rise tremendously by 2050. Bone formation and remodeling are complex processes that are disturbed in a variety of diseases influenced by various hormones.

Objective

This study aimed to review and present the roles of various hormones that regulate bone remodeling of the craniofacial complex.

Methods

A literature search was conducted on PubMed and Google Scholar for studies related to hormones and jawbone. Search strategies included the combinations ("name of hormone" + "dental term") of the following terms: "hormones", "oxytocin", "estrogen", "adiponectin", "parathyroid hormone", "testosterone", "insulin", "angiotensin", "cortisol", and "erythropoietin", combined with a dental term "jaw bone", "alveolar bone", "dental implant", "jaw + bone regeneration, healing or repair", "dentistry", "periodontitis", "dry socket", "osteoporosis" or "alveolitis". The papers were screened according to the inclusion criteria from January 1, 2000 to March 31, 2021 in English. Publications included reviews, book chapters, and original research papers; in vitro studies, in vivo animal, or human studies, including clinical studies, and meta-analyses.

Results

Bone formation and remodeling is a complex continuous process involving many hormones. Bone volume reduction following tooth extractions and bone diseases, such as periodontitis and osteoporosis, cause serious problems and require a great understanding of the process.

Conclusion

Hormones are with us all the time, shape our development and regulate homeostasis. Newly discovered effects of hormones influencing bone healing open the possibilities of using hormones as therapeutics to combat bone-related diseases.

Impact of Compensated Cirrhosis Etiology on Postoperative Outcomes Following Total Knee Arthroplasty

BACKGROUND

Cirrhotics often demonstrate worse outcomes than their non-cirrhotic counterparts following orthopedic surgery; however, there are limited arthroplasty-focused data on this occurrence. Additionally, variances in postoperative outcomes among the different etiologies of cirrhosis have not been well described. The aim of this study is to evaluate the effect compensated cirrhosis had on postoperative outcomes following elective total knee arthroplasty (TKA).

METHODS

In total, 1,734,568 patients who underwent primary TKA from 2006 to 2013 were identified using the Medicare Claims Database. Patients were divided into those with a history of compensated cirrhosis and those with no history of liver disease. Subgroup analysis was performed based on the etiology of cirrhosis. Multivariate logistic regression was used to evaluate postsurgical outcomes of interest.

RESULTS

Cirrhotic patients had higher risk of developing disseminated intravascular coagulation (odds ratio [OR] 2.76, P = .003), encephalopathy (OR 3.00, P < .001), and periprosthetic infection (OR 1.79, P < .001) compared to controls. Following subgroup analysis, alcoholic cirrhotics had high risk of periprosthetic infection (OR 2.12, P < .001), fracture (OR 3.28, P < .001), transfusion (OR 2.45, P < .001), and encephalopathy (OR 7.34, P < .001) compared to controls. Viral cirrhosis was associated with an increase in 90-day charges ($14,941, P < .001) compared to controls, while cirrhosis secondary to other causes was associated with few adverse outcomes compared to controls.

CONCLUSION

Liver cirrhosis is an independent risk factor for increased perioperative morbidity and financial burden following TKA. Cirrhosis due to etiologies other than viral infections and alcoholism are associated with few adverse outcomes. Surgeons should be aware of these complications to properly optimize postoperative management.

The Pharmacologic Management of Osteoporosis in Primary Biliary Cholangitis: A Systematic Review and Meta-Analysis

INTRODUCTION

Osteoporosis is a common complication of primary biliary cholangitis (PBC) yet evidence for effective therapy is lacking. We sought to review all randomized controlled trials evaluating pharmacotherapy against placebo or no intervention for treatment of osteoporosis in PBC.

METHODOLOGY

A comprehensive database search was conducted from inception through 29 March 2017. The primary outcome was incidence of fractures; secondary outcomes were change in bone mineral density (BMD) and adverse events. We assessed studies for risk of bias, graded quality of evidence, and used meta-analysis to obtain overall effect by pooling studies of the same drug class.

RESULTS

We identified 11 randomized controlled trials evaluating bisphosphonates (3), hormone replacement therapy (2), ursodeoxycholic acid (1), obeticholic acid (1), cyclosporin A (1), vitamin K (1), calcitriol (1), and sodium fluoride (1). No intervention significantly reduced fractures compared to control. Although significant improvement in BMD was seen in one study with alendronate, a third-generation bisphosphonate, no significant improvement was seen on pooled analysis of all bisphosphonates including first-generation bisphosphonates (standard mean difference 0.41, p = 0.68). On pooled analysis, hormone replacement therapy modestly improved lumbar BMD (standard mean difference 0.69, p = 0.02), but with significantly increased adverse events (odds ratio 8.82, p = 0.01).

CONCLUSIONS

There is a lack of high-quality evidence supporting the efficacy of any treatment of osteoporosis in PBC. This may be explained by lack of power in the included studies. However, our current understanding of PBC-related osteoporosis indicates that it results from decreased bone formation, which may explain the attenuated effect of traditional antiresorptive agents. Future studies should investigate newer anabolic bone agents.

Bone Health in Patients With Liver Diseases

Osteoporosis is the most common bone disease in chronic liver disease (CLD) resulting in frequent fractures and leading to significant morbidity in this population. In addition to patients with cirrhosis and chronic cholestasis, patients with CLD from other etiologies may be affected in the absence of cirrhosis. The mechanism of osteoporosis in CLD varies according to etiology, but in cirrhosis and cholestatic liver disease it is driven primarily by decreased bone formation, which differs from the increased bone resorption seen in postmenopausal osteoporosis. Direct toxic effects from iron and alcohol play a role in hemochromatosis and alcoholic liver disease, respectively. Chronic inflammation also has been proposed to mediate bone disease in viral hepatitis and nonalcoholic fatty liver disease. Treatment trials specific to osteoporosis in CLD are small, confined to primary biliary cholangitis and post-transplant patients, and have not consistently demonstrated a benefit in this population. As it stands, prevention of osteoporosis in CLD relies on the mitigation of risk factors such as smoking and alcohol use, treatment of underlying hypogonadism, and encouraging a healthy diet and weight-bearing exercise. The primary medical intervention for the treatment of osteoporosis in CLD remains bisphosphonates though a benefit in terms of fracture reduction has never been shown. This review outlines what is known regarding the pathogenesis of bone disease in CLD and summarizes current and emerging therapies.

Preventative care in cholestatic liver disease: Pearls for the specialist and subspecialist

Cholestatic liver diseases (CLDs) encompass a variety of disorders of abnormal bile formation and/or flow. CLDs often lead to progressive hepatic insult and injury and following the development of cirrhosis and associated complications. Many such complications are clinically silent until they manifest with severe sequelae, including but not limited to life-altering symptoms, metabolic disturbances, cirrhosis, and hepatobiliary diseases as well as other malignancies. Primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) are the most common CLDs, and both relate to mutual as well as unique complications. This review provides an overview of PSC and PBC, with a focus on preventive measures aimed to reduce the incidence and severity of disease-related complications.

Primary biliary cholangitis and bone disease

Osteoporosis, characterized by compromised bone strength leading to fragility fractures, is a common event in patients with primary biliary cholangitis (PBC). Osteomalacia, defined by poor bone mineralization is very uncommon. The pathogenesis of osteoporosis is not well clarified, but it mainly results from low bone formation. Few reports have revealed increased bone resorption, particularly in end-stage disease. The prevalence of osteoporosis is about 35% in the most significant studies, and it depends on the diagnostic criteria and severity of liver damage. Osteoporosis is associated with age, postmenopausal status, duration of PBC and advanced histological stage. Bone densitometry is the common method for the diagnosis of osteoporosis and should be performed in all patients with PBC. Lateral X-rays of the dorsal and lumbar spine should also be carried out to disclose vertebral fractures. There is no specific treatment but bisphosphonates, especially alendronate and ibandronate, efficiently increases bone mass and prevents bone loss. Despite these positive effects on bone mass no clear results on decreasing the fracture rate have been demonstrated, probably because the low number of patients included in the trials. The potential value of new agents requires further evaluation.

Sclerostin Expression in Bile Ducts of Patients With Chronic Cholestasis May Influence the Bone Disease in Primary Biliary Cirrhosis

Sclerostin is involved in the regulation of osteoblastogenesis and little is known about its role in the development of bone disease in primary biliary cirrhosis (PBC), characterized by low bone formation. Therefore, we have assessed the circulating levels and the liver expression of sclerostin in this cholestatic disease. Serum sclerostin levels were measured in 79 women with PBC (mean age 60.6 ± 1.2 years) and in 80 control women. Lumbar and femoral bone mineral density (BMD), as well as parameters of mineral metabolism and bone remodeling, were measured. Moreover, sclerostin gene (SOST) expression in the liver was assessed by real-time PCR in samples of liver tissue taken by biopsy in 11 PBC patients and in 5 normal liver specimens. Presence and distribution of sclerostin was evaluated in liver slices from 11 patients by immunohistochemistry. The severity of histologic lesions was assessed semiquantitatively in the same liver samples. PBC patients had higher sclerostin levels than controls (75.6 ± 3.9 versus 31.7 ± 1.6 pmol/L, p < 0.001). Serum sclerostin correlated inversely with markers of bone formation and resorption. Sclerostin mRNA in the liver was overexpressed compared with control samples (2.7-fold versus healthy liver). Sclerostin was detected by immunohistochemistry in 7 of the 11 liver samples, mainly located in the bile ducts. Liver sclerostin was associated with the severity of cholangitis (p = 0.02) and indirectly with the degree of lobular inflammation (p = 0.03). Sclerostin mRNA expression was higher in samples that tested positive by immunohistochemistry and particularly in those with lobular granuloma (p = 0.02). The increased expression of sclerostin in the liver and the association with histologic cholangitis may explain the high serum levels of this protein in patients with PBC, thus suggesting that sclerostin may influence the decreased bone formation in this cholestatic disease. © 2016 American Society for Bone and Mineral Research.

Women and primary biliary cirrhosis

Primary biliary cirrhosis occurs more frequently in women, and previous studies indicated that the average age of primary biliary cirrhosis (PBC) onset makes pregnancy in PBC patients uncommon. However, more recently, improved diagnostic testing has enabled detection of PBC in younger women, including those of childbearing age. This has led investigators to become increasingly interested in the relationship between the ontogeny of PBC and pregnancy. Published cases indicate that the typical age for pregnant women to be diagnosed with PBC is in the early 30s, and that during gestation, pruritus and jaundice are the most common symptoms. During gestation, susceptible women may experience onset of PBC resulting from the drastic changes in female hormones; this would include not only the mitochondrial damage due to accumulation of bile acids but also changes in the immune response during the different stages of pregnancy that might play an important role in the breakdown of self-tolerance. The mechanisms underlying the potential relationship between PBC and pregnancy warrant further investigation. For women first diagnosed with PBC during gestation, or those for whom first appearance of a flare up occurs during and postpartum, investigation of the immune response throughout gestation could provide new avenues for immunologic therapeutic intervention and the discovery of new treatment strategies for PBC.

Serum vitamin D level is associated with disease severity and response to ursodeoxycholic acid in primary biliary cirrhosis

BACKGROUND

Serum vitamin D levels are associated with bone complications in patients with primary biliary cirrhosis (PBC). Increasing evidence suggests a nonskeletal role of vitamin D in various autoimmune and liver diseases.

AIM

To investigate the clinical relevance of vitamin D levels in PBC, especially their association with the therapeutic effects of ursodeoxycholic acid (UDCA).

METHODS

Consecutive PBC patients were retrospectively reviewed. 25-hydroxyvitamin D [25(OH)D] levels were determined in frozen serum samples collected before initiation of UDCA treatment. Response to UDCA was evaluated by Paris-I and Barcelona criteria. Logistic regressions were performed to identify the treatment response-associated parameters.

RESULTS

Among 98 patients, the mean serum 25(OH)D concentration was 17.9 ± 7.6 ng/mL. 25(OH)D levels decreased with increasing histological stage (P = 0.029) and were negatively correlated with bilirubin and alkaline phosphatase levels. After 1 year of UDCA therapy, 31 patients failed to achieve complete response according to Paris-I criteria. The baseline 25(OH)D level was significantly lower in nonresponders (14.8 ± 6.4 vs. 19.3 ± 7.6 ng/mL, P = 0.005). Vitamin D deficiency at baseline was associated with an increased risk of incomplete response independent of advanced stages (OR = 3.93, 95% CI = 1.02-15.19, P = 0.047). Similar results were obtained when biochemical response was evaluated by Barcelona criteria. Furthermore, 25(OH)D levels were lower in patients who subsequently suffered death or liver transplantation (12.1 ± 4.6 vs. 18.4 ± 7.6 ng/mL, P = 0.023).

CONCLUSIONS

25(OH)D level is associated with biochemical and histological features in PBC. Pre-treatment vitamin D status is independently related to subsequent response to UDCA. Our results suggest that vitamin D status may have important clinical significance in PBC.

Wilson's disease: An endocrine revelation

Wilson's disease is an inherited disorder of copper metabolism. The affected patients, who otherwise have a near normal life span, may often suffer from some potentially treatable and under recognized endocrine disorders that may hinder their quality of life. We explored previously published literature on the various endocrine aspects of this disease with their probable underlying mechanisms, highlighting the universal need of research in this area.

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.

Efficacy of different therapeutic regimens on hepatic osteodystrophy in chronic viral liver disease

BACKGROUND AND AIMS

Metabolic bone disease is common in patients with chronic liver disease. Comparative studies on the efficacies of antiosteoporotic agents in hepatic osteodystrophy have not been conducted yet. The aim of this study was to evaluate the safety and efficacy of different therapeutic regimens on hepatic osteodystrophy.

METHODS

Eighty-one patients (mean age 48.9 ± 10 years; 50 cases with chronic viral hepatitis and 31 patients with cirrhosis) were enrolled in the study. Treatment groups consisted of 61 patients who had reduced T scores in at least one region, selected randomly and treated for 1 year with vitamin D 400 IU, calcitonin 200 IU, alendronate 10 mg, alendronate 70 mg, or risedronate 5 mg. An untreated group consisting of 20 patients who had no reduction in T scores was followed up during the study period.

RESULTS

No significant adverse effects, including esophageal variceal hemorrhage, were detected. According to the T score at the end of the first year compared with baseline, significant improvements in bone mineral density were observed at all regions with alendronate 70 mg; improvements at the lumbar spine (LS) and distal radius regions with alendronate 10 mg; at the LS and distal radius regions with risedronate; at the LS region with calcitonin; and at the femoral neck region with vitamin D.

CONCLUSION

All therapeutic regimens seemed to be safe, and oral biphosphonates were the most effective in preventing both cortical and trabecular bone loss in patients with chronic viral liver disease. Larger studies with longer follow-up are warranted in hepatic osteodystrophy of chronic viral liver diseases.

MELD score, insulin-like growth factor 1 and cytokines on bone density in end-stage liver disease

AIM

To determine the contributions of insulin-like growth factor 1 (IGF-1), cytokines and liver disease severity to bone mineral density in patients pre-transplantation.

METHODS

Serum IGF-1, tumor necrosis factor-α (TNFα) and interleukin 6 (IL-6) were measured and the Model for End-Stage Liver Disease (MELD) score calculated in 121 adult patients referred to a single centre for liver transplantation. Bone mineral density (BMD) of the lumbar spine and femoral neck were assessed via dual energy X-ray absorptiometry. Demographics, liver disease etiology, medication use and relevant biochemistry were recorded.

RESULTS

A total of 117 subjects were included, with low BMD seen in 68.6%, irrespective of disease etiology. In multivariable analysis, low body mass index (BMI), increased bone turnover and low IGF-1 were independent predictors of low spinal bone density. At the hip, BMI, IGF-1 and vitamin D status were predictive. Despite prevalent elevations of TNFα and IL-6, levels did not correlate with degree of bone loss. The MELD score failed to predict low BMD in this pre-transplant population.

CONCLUSION

Osteopenia/osteoporosis is common in advanced liver disease. Low serum IGF-1 is weakly predictive but serum cytokine and MELD score fail to predict the severity of bone disease.

Osteoporosis following organ transplantation: pathogenesis, diagnosis and management

Organ transplantation has become popular for the management of various chronic illnesses. With the advent of modern immunosuppressive treatments, the longevity of transplant recipients has increased. Consequently, morbid complications such as osteoporosis and bone fractures are seen at an increasing frequency in this population. In most transplant recipients, bone mineral density (BMD) falls shortly after transplantation. However, bone fracture rate plateaus in all except for post-renal transplant patients. Although the underlying pathophysiologic mechanism for this difference is not fully understood, potential mechanisms for sustained bone loss in renal transplant recipients may be persistent phosphorus wasting and defective bone mineralization. Current treatment regimens are based on studies in a small numbers of subjects with BMD as the primary outcome. Although BMD is recognized as a gold standard in the assessment of bone fracture risk, to date, its association with bone fracture risk in the general post-transplant population is not robust. Therefore, randomized controlled trials with bone fracture as the primary end point are crucial. The development of noninvasive bone markers in distinguishing bone turnover and bone mineralization status is also pivotal since skeletal lesions are heterogeneous in various organ transplantations. The elucidation of these underlying skeletal lesions is necessary for the consideration of selective treatment in this population.

Circulating osteocalcin concentrations are associated with parameters of liver fat infiltration and increase in parallel to decreased liver enzymes after weight loss

SUMMARY

The expression of liver genes was associated with insulin action in osteocalcin knockout mice. Our findings suggest that osteocalcin may play a role in the development of insulin resistance-associated fatty liver disease.

INTRODUCTION

The expression of insulin target genes was decreased in the liver of mice lacking osteocalcin. We aimed to explore the association of liver enzymes with osteocalcin.

METHODS

The associations were evaluated in a cross-sectional study (266 men) and following weight loss in 28 obese subjects (nine male, 19 females).

RESULTS

In the cross-sectional study, circulating osteocalcin concentration was negatively associated with alanine transaminase (ALT) (p = 0.002) and aspartate transaminase (AST) levels (p = 0.008). These associations were especially significant in non-obese subjects (n = 191). In a multiple linear regression analysis, age (p = 0.008), insulin sensitivity (p = 0.001), and osteocalcin (p = 0.04) independently contributed to 22% of ALT variance in these latter subjects. In the weight loss study, the increase in circulating osteocalcin concentration (+70.6 ± 29.3 vs. +32 ± 13.5%, p = 0.021) was significantly greater in subjects with the highest decrease in ALT levels, despite similar baseline BMI, insulin resistance and degree of weight loss than remaining subjects. In fact, the change in ALT levels were linearly associated with those of osteocalcin (r = -0.55, p = 0.003).

CONCLUSIONS

In summary, our findings suggest a bone-liver axis in which osteocalcin might be the active regulator.

Low bone mass and severity of cholestasis affect fracture risk in patients with primary biliary cirrhosis

BACKGROUND & AIMS

The influence of osteoporosis and liver disease on fracture risk is not well characterized in patients with primary biliary cirrhosis (PBC). We studied a large series of women with PBC to assess the prevalence and risk factors for fractures and the fracture threshold.

METHODS

In female patients with PBC (n = 185; age, 55.7 +/- 0.7 years; range 28-79 years), age, duration of PBC, menopausal status, and histologic stage and severity of liver disease were assessed. Vertebral and non-vertebral fractures were recorded in 170 and 172 patients, respectively. Osteoporosis and osteopenia were diagnosed based on densitometry analysis.

RESULTS

The prevalences of vertebral, non-vertebral, and overall fractures were 11.2%, 12.2%, 20.8%, respectively. Osteoporosis was significantly more frequent in patients with PBC than in normal women. Osteoporosis was associated with age, weight, height, histologic stage, severity, and duration of liver damage; fractures were associated with osteoporosis, menopause, age, and height but not with severity of PBC. Osteoporosis was a risk factor for vertebral fracture (odds ratio [OR], 8.48; 95% confidence interval [CI]: 2.67-26.95). Lumbar T score <-1.5 (OR, 8.27; 95% CI: 1.84-37.08) and femoral neck T score <-1.5 (OR, 6.83; 95% CI: 1.48-31.63) were significant risk factors for vertebral fractures.

CONCLUSIONS

Fractures, particularly vertebral fractures, are associated with osteoporosis, osteopenia, and T scores less than -1.5, whereas osteoporosis and osteopenia are associated with the severity of liver damage. Patients with T scores less than -1.5 might require additional monitoring and be considered for therapy to prevent fractures.

Hepatic osteodystrophy and liver cirrhosis

AIM: To investigate the correlation between hepatic osteodystrophy and osteoporosis in patients with liver cirrhosis.

METHODS: Bone mineral density of the patients (n = 55) and that of the control group (n = 30) were measured by dual-energy X-ray absorptiometry. All the women in the study were premenopausal. Deoxypyridinoline, pyridinoline and urinary Ca²⁺ were measured as bone destruction markers, while alkaline phosphatase (ALP), osteocalcin and insulin-like growth factor-1 (IGF-1) were measured as bone formation markers. Furthermore, interleukin-1 (IL-1), IL-6, tumor necrosis factor α (TNF-α), vitamin D3, direct bilirubin, albumin, cortisol and parathyroid hormone (PTH) levels were measured. The independent Student t test and χ² test were employed in comparing both groups, and the Pearson correlation test was used to determine associations.

RESULTS: Comparing cirrhosis and control groups, lumbar total T-score (-1.6 ± 1.2 g/cm²vs -0.25 ± 1.3 g/cm², P < 0.001), lumbar total Z-score (-1.2 ± 1.23 g/cm²vs -0.6 ± 1.3 g/cm², P < 0.001), total femur T-score (-0.05 ± 1 g/cm²vs -0.6 ± 0.9 g/cm², P = 0.003) and total femur Z-score (-0.08 ± 1.5 g/cm²vs 0.7 ± 0.9 g/cm², P = 0.003) showed significantly lower values in the cirrhosis group. Blood ALP level (109.2 ± 57 U/L vs 62.6 ± 32.5 U/L, P < 0.001), IL-6 level (27.9 ± 51.6 pg/mL vs 3.3 ± 3.1 pg/mL, P = 0.01), TNF-α level (42.6 ± 33.2 pg/mL vs 25.3 ± 12.3 pg/mL, P = 0.007) and direct bilirubin level (0.9 ± 0.7 mg/dL vs 0.3 ± 0.2 mg/dL, P < 0.001) were significantly higher in the cirrhosis group. IGF-1 level (47.7 ± 26.2 ng/mL vs 143.4 ± 53.2 ng/mL, P < 0.001), osteocalcin level (1.05 ± 2.5 ng/mL vs 7.0 ± 13 ng/mL, P = 0.002) and 24 h urinary Ca²⁺ (169.6 ± 227.2 mg/dL vs 287 ± 168.6 mg/dL, P = 0.003) were significantly lower in the cirrhosis group. Urinary deoxypyridinoline/creatinine (9.4 ± 9.9 pmol/μmol vs 8.1 ± 5.3 pmol/μmol, P = 0.51), urinary pyridinoline/creatinine (51.3 ± 66.6 pmol/μmol vs 29 ± 25.8 pmol/μmol, P = 0.08), blood IL-1 level (3.4 ± 8.8 pg/mL vs 1.6 ± 3.5 pg/mL, P = 0.29), vitamin D3 level (18.6 ± 13.3 μg/L vs 18.4 ± 8.9 μg/L, P = 0.95), cortisol level (11.1 ± 4.8 μg/dL vs 12.6 ± 4.3 μg/dL, P = 0.15) and PTH level (42.7 ± 38 μg/dL vs 34.8 ± 10.9 μg/dL, P = 0.27) were not significantly different.

CONCLUSION: Hepatic osteodystrophy is an important complication encountered in patients with liver cirrhosis and all patients should be monitored for hepatic osteodystrophy.

Lithocholic acid downregulates vitamin D effects in human osteoblasts

BACKGROUND

Osteoporosis is a common complication in chronic cholestasis. It has been proposed that retained substances such as bile acids may produce a damaging effect on bone cells. This study analyses the effects of lithocholic acid (LCA) on cell survival and vitamin D metabolism in human osteoblasts (hOB).

MATERIALS AND METHODS

Human osteoblasts cultures were performed with or without foetal bovine serum (FBS) or human albumin (HA) at different LCA concentrations and times with or without vitamin D.

RESULTS

Lithocholic acid at concentrations higher than 10(-5 )M decreased cell survival. This effect was partially prevented by the presence of FBS or HA. Vitamin D stimulated CYP24A, BGLAP and TNFSF11 expression in hOB and these effects were modified by nontoxic LCA concentrations. LCA significantly decreased vitamin D stimulation of CYP24A, BGLAP and TNFSF11 gene expression at 72%, 79% and 56% (respectively). LCA alone has an agonistic effect, as has vitamin D, thus partially increasing CYP24A and BGLAP expression, but with no changes on TNFRSF11B expression. Equivalent effects of the LCA were observed by performing gene reporter assays using MG-63 cells transfected with constructs containing CYP24A1 promoter regions.

CONCLUSIONS

Lithocholic acid decreases the stimulatory effect of vitamin D on CYP24A, BGLAP and TNFSF11 expression in hOB. This effect is produced through vitamin D response elements (VDREs), located in the promoter regions of these genes, suggesting that LCA acts as a mild analogous of vitamin D, interacting with the vitamin D receptor. These results may explain the potential deleterious effects of retained bile acids on hOB.

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.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease with a slowly progressive course. Without treatment, most patients eventually develop fibrosis and cirrhosis of the liver and may need liver transplantation in the late stage of disease. PBC primarily affects women (female preponderance 9–10:1) with a prevalence of up to 1 in 1,000 women over 40 years of age. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The diagnosis is based on sustained elevation of serum markers of cholestasis, i.e., alkaline phosphatase and gamma-glutamyl transferase, and the presence of serum antimitochondrial antibodies directed against the E2 subunit of the pyruvate dehydrogenase complex. Histologically, PBC is characterized by florid bile duct lesions with damage to biliary epithelial cells, an often dense portal inflammatory infiltrate and progressive loss of small intrahepatic bile ducts. Although the insight into pathogenetic aspects of PBC has grown enormously during the recent decade and numerous genetic, environmental, and infectious factors have been disclosed which may contribute to the development of PBC, the precise pathogenesis remains enigmatic. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at adequate doses of 13–15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. The mode of action of UDCA is still under discussion, but stimulation of impaired hepatocellular and cholangiocellular secretion, detoxification of bile, and antiapoptotic effects may represent key mechanisms. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarizes current knowledge on the clinical, diagnostic, pathogenetic, and therapeutic aspects of PBC.

Etiopathogenesis of hepatic osteodystrophy in Wistar rats with cholestatic liver disease

The pathophysiology of hepatic osteodystrophy (HO) remains poorly understood. Our aim was to evaluate bone histomorphometry, biomechanical properties, and the role of the growth hormone (GH)/insulin-like growth factor-I (IGF-I) system in the onset of this disorder. Forty-six male Wistar rats were divided into two groups: sham-operated (SO, n = 23) and bile duct-ligated (BDL, n = 23). Rats were killed on day 30 postoperatively. Immunohistochemical expression of IGF-I and GH receptor was determined in liver tissue and in the proximal growth plate cartilage of the left tibia. Histomorphometric analysis was performed in the right tibia, and the right femur was used for biomechanical analysis. The maximal force at fracture and the stiffness of the mid-shaft femur were, respectively, 53% and 24% lower in BDL compared to SO. Histomorphometric measurements showed low cancellous bone volume and decreased cancellous bone connectivity in BDL, compatible with osteoporosis. This group also showed increased mineralization lag time, indicating disturbance in bone mineralization. Serum levels of IGF-I were lower in BDL (basal 1,816 +/- 336 vs. 30 days 1,062 +/- 191 ng/ml, P < 0.0001). BDL also showed higher IGF-I expression in the liver tissue but lower IGF-I and GH receptor expression in growth plate cartilage than SO. Osteoporosis is the most important feature of HO; BDL rats show striking signs of reduced bone volume and decreased bone strength, as early as after 1 month of cholestasis. The endocrine and autocrine-paracrine IGF-I systems are deeply affected by cholestasis. Further studies will be necessary to establish their role in the pathogenesis of HO.

Management of autoimmune and cholestatic liver disorders

The management of autoimmune and cholestatic liver disorders is a challenging area of hepatology. Autoimmune and cholestatic liver diseases represent a comparatively small proportion of hepatobiliary disorders, yet their appropriate management is of critical importance for patient survival. In this article, management strategies are discussed, including the indications and expectations of pharmacologic therapy, endoscopic approaches, and the role of liver transplantation.

Isoform of fibronectin mediates bone loss in patients with primary biliary cirrhosis by suppressing bone formation

Osteoporosis is a major cause of morbidity and decreased quality of life in patients with chronic cholestatic liver disease. It is established that this osteoporosis results from decreased bone formation, but the mechanisms for the interaction between liver and bone remain elusive. The aim of this study was to test the hypothesis that an increase in the production of cellular fibronectins during liver disease may result in decreased osteoblast-mediated mineralization and thus explain the decrease in bone formation. We performed a prospective cross-sectional study in patients with primary biliary cirrhosis and matched controls, followed by experiments on human and mouse osteoblasts in culture and injections in mice in vivo. In patients with primary biliary cirrhosis, the oncofetal domain of fibronectin correlated significantly with the decrease in osteocalcin, a marker of bone formation (r = -0.57, p < 0.05). In vitro, amniotic fluid fibronectin (aFN) containing mainly the oncofetal domain and EIIIA domain resulted in decreased osteoblast-mediated mineralization in human osteoblasts (69% decrease at 100 microg/ml; p < 0.01) and mouse osteoblasts (71% decrease; p < 0.05). Removing the EIIIA domain from aFN similarly suppressed mineralization by osteoblasts (78% decrease; p < 0.05). Injection of labeled aFN in mice showed that it infiltrates the bone, and its administration over 10 days resulted in decreased trabecular BMD (17% drop; p < 0.05), mineralizing surface (30% drop; p < 0.005), and number of osteoblasts (45% drop; p < 0.05). Increased production of a fibronectin isoform containing the oncofetal domain and its release in the circulation in patients with primary biliary cirrhosis is at least partially responsible for the decrease in bone formation seen in these patients. This establishes that a molecule that has thus far been viewed as an extracellular matrix protein exerts hormone-like actions.

Clinical features and management of primary biliary cirrhosis

Primary biliary cirrhosis (PBC), which is characterized by progressive destruction of intrahepatic bile ducts, is not a rare disease since both prevalence and incidence are increasing during the last years mainly due to the improvement of case finding strategies. The prognosis of the disease has improved due to both the recognition of earlier and indolent cases, and to the wide use of ursodeoxycholic acid (UDCA). New indicators of prognosis are available that will be useful especially for the growing number of patients with less severe disease. Most patients are asymptomatic at presentation. Pruritus may represent the most distressing symptom and, when UDCA is ineffective, cholestyramine represents the mainstay of treatment. Complications of long-standing cholestasis may be clinically relevant only in very advanced stages. Available data on the effects of UDCA on clinically relevant end points clearly indicate that the drug is able to slow but not to halt the progression of the disease while, in advanced stages, the only therapeutic option remains liver transplantation.

Osteoporosis in primary biliary cirrhosis: pathogenesis and treatment

Osteoporosis, characterized by loss of bone strength leading to fragility fractures, is a common event in patients who have primary biliary cirrhosis. Although its pathogenesis is not well known, it results mainly from low bone formation. There is no specific treatment, but bisphosphonates, especially alendronate, effectively increases bone mass and prevents bone loss. Despite these favorable effects on bone mass, no clear effects on decreasing the fracture rate are demonstrated, probably because of the low number of patients included in the trials. The potential usefulness of new agents requires further evaluation.

Primary biliary cirrhosis is not an additional risk factor for bone loss in women receiving regular calcium and vitamin D supplementation: a controlled longitudinal study

BACKGROUND AND GOALS

Alterations in bone metabolism in primary biliary cirrhosis (PBC) are generally considered to be highly prevalent and severe, but no data are available from prospective studies with adequate control groups. The aims of this study were: (1) to measure changes in bone mineral density (BMD) over time; (2) to correlate the degree of bone loss with the severity of liver disease; and (3) to characterize bone disease in PBC patients receiving regular calcium and vitamin D supplementation.

STUDY

We enrolled 118 women with PBC (mean age+/-SD: 56+/-11 y; 72% postmenopausal; 43% with cirrhosis), and measured BMD (lumbar spine, DXA-Hologic) at entry and serially over the following 5 years. The controls were 472 healthy women selected from a large observational group matched for age and menopausal status (mean age+/-SD: 55+/-10 y; 73% postmenopausal).

RESULTS

Mean BMD was 0.851+/-0.142 g/cm2 in the PBC group and 0.857+/-0.158 g/cm2 in the control group; the prevalence of osteoporosis was 28% and 29%, respectively. BMD significantly correlated with age and postmenopausal status, but not with liver cirrhosis or serum bilirubin levels. The biochemical markers of bone turnover were high in about 50% of the patients. The yearly bone loss in the PBC group was 0.008 g/cm2 (95% confidence interval: 0.014-0.003) similar to that calculated in the control group.

CONCLUSIONS

Among patients with PBC, the prevalence of osteoporosis and the yearly rate of BMD loss are similar to those observed in the general population, and are not associated with the severity of liver disease.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology characterized by injury of the intrahepatic bile ducts that may eventually lead to liver failure. Affected individuals are usually in their fifth to seventh decades of life at time of diagnosis, and 90% are women. Annual incidence is estimated between 0.7 and 49 cases per million-population and prevalence between 6.7 and 940 cases per million-population (depending on age and sex). The majority of patients are asymptomatic at diagnosis, however, some patients present with symptoms of fatigue and/or pruritus. Patients may even present with ascites, hepatic encephalopathy and/or esophageal variceal hemorrhage. PBC is associated with other autoimmune diseases such as Sjogren's syndrome, scleroderma, Raynaud's phenomenon and CREST syndrome and is regarded as an organ specific autoimmune disease. Genetic susceptibility as a predisposing factor for PBC has been suggested. Environmental factors may have potential causative role (infection, chemicals, smoking). Diagnosis is based on a combination of clinical features, abnormal liver biochemical pattern in a cholestatic picture persisting for more than six months and presence of detectable antimitochondrial antibodies (AMA) in serum. All AMA negative patients with cholestatic liver disease should be carefully evaluated with cholangiography and liver biopsy. Ursodeoxycholic acid (UDCA) is the only currently known medication that can slow the disease progression. Patients, particularly those who start UDCA treatment at early-stage disease and who respond in terms of improvement of the liver biochemistry, have a good prognosis. Liver transplantation is usually an option for patients with liver failure and the outcome is 70% survival at 7 years. Recently, animal models have been discovered that may provide a new insight into the pathogenesis of this disease and facilitate appreciation for novel treatment in PBC.

Primary biliary cirrhosis and osteoporosis: a case-control study

Osteoporosis is a common complication of chronic liver disease, from cholestatic disorders to autoimmune, alcoholic, and posthepatitic cirrhosis. Osteoporosis appears more striking in patients with primary biliary cirrhosis (PBC) because the disease usually affects elderly women, who are naturally prone to osteoporosis. Our aims were (1) to compare the prevalence of osteoporosis (T-score <-2.5 SD) between PBC patients and a group of age-and sex-matched controls consisting of healthy subjects from the general population; and (2) to identify the main risk factors for the development of bone loss. Thirty-three women with PBC (mean age, 47.3 +/- 10.4 years) and 66 healthy subjects were enrolled in the study. Bone mineral density (BMD) was assessed at the lumbar spine by dual-photon X-ray absorptiometry. Bone metabolism was evaluated by measuring serum calcium corrected for serum albumin, 25-hydroxyvitamin D (25-OH vit D), parathyroid hormone, and osteocalcin. Vertebral fractures were analyzed using vertebral fracture assessment (VFA). The mean T-score was lower in the PBC group compared to healthy controls, with a significant statistical difference (-2.39 +/- 0.93 and -1.47 +/- 0.99 in lumbar spine and total hip, respectively, in the PBC group versus -0.99 +/- 0.51 and -0.56 +/- 1.14 in healthy controls (P < 0.001). The prevalence of osteoporosis was 51.5% in the PBC group versus 22.7% in healthy controls with a statistically significant difference (P = 0.004). BMD of the PBC group was significantly correlated positively with body mass index (BMI) and 25-OH vit D, and negatively with menopausal status, duration of disease, and parathyroid hormone (PTH) levels. Vertebral fractures were present in 9% of the patients. We found that osteoporosis is more prevalent in women with PBC than in the general population. BMI, menopausal status, duration of the disease, and vitamin D deficiency are the main risk factors for osteoporosis in this liver disease.

Human parathyroid hormone 1-34 prevents bone loss in experimental biliary cirrhosis in rats

BACKGROUND & AIMS

Reduced bone mass and increased fracture rate are complications of primary biliary cirrhosis (PBC). The effect of intermittent administration of human parathyroid hormone (hPTH) 1-34 on bone mass and architecture in bile duct-ligated (BDL) rats was studied.

METHODS

Six-month-old male rats were subjected to BDL or sham operation (SO) and were treated from the second postoperative week intermittently with either hPTH 1-34 40 microg/kg per day, 80 microg/kg per day, or a vehicle for 4 weeks. Femoral and tibial bones were evaluated ex vivo by dual x-ray absorptiometry, microcomputed tomography, and histomorphometry. Serum osteocalcin and urinary deoxypyridinoline cross-links (DPD) were determined.

RESULTS

BDL rats had decreased bone mass compared with SO rats as indicated by a 6% decrease in femoral and tibial bone mineral density (BMD), 18% reduction in femoral trabecular bone volume (bone volume/total volume [BV/TV]), 17% decrease in trabecular thickness, and 10% decrease in tibial cortical thickness. The administration of hPTH 1-34 at 40 microg/kg per day increased femoral and tibial BMD (9% and 9%), femoral trabecular BV/TV (50%), trabecular thickness (50%), tibial cortical thickness (17%), and serum osteocalcin (82%). On the other hand, hPTH 1-34 80 microg/kg per day had no effect on BMD and tibial cortical thickness, was associated with a smaller increase in trabecular BV/TV (24%), and had a higher osteoclast number and DPD compared with untreated BDL rats and the lower hPTH 1-34 dose treatment group.

CONCLUSIONS

BDL rats exhibit loss of bone mass and structure, which can be prevented by the intermittent administration of hPTH 1-34, a potential therapy for osteoporosis in PBC.

Osteoporosis in haemophilia - an underestimated comorbidity?

A relationship between haemophilia and osteoporosis has been suggested, leading to the initiative for a larger study assessing this issue. Bone mineral density (BMD) was measured by osteodensitometry using dual energy X-ray absorptiometry (DEXA) in 62 male patients with severe haemophilia A; mean age 41 +/- 13.1 years, mean body mass index (BMI) 23.5 +/- 3.6 kg m(-2). Using the clinical score suggested by the World Federation of Hemophilia, all patients were assessed to determine the severity of their arthropathy. A reduced BMD defined as osteopenia and osteoporosis by World Health Organization criteria was detected in 27/62 (43.5%) and 16/62 (25.8%) patients, respectively. Fifty-five of sixty-two (88.7%) patients suffered from haemophilic arthropathy. An increased number of affected joints and/or an increased severity were associated with lower BMD in the neck of femur. Pronounced muscle atrophy and loss of joint movement were also associated with low BMD. Furthermore, hepatitis C, low BMI and age were found to be additional risk factors for reduced BMD in the haemophiliac. Our data shows that in haemophilic patients osteoporosis represents a frequent concomitant observation. The main cause for reduced bone mass in the haemophiliac is most probably the haemophilic arthropathy being typically associated with chronic pain and loss of joint function subsequently leading to inactivity. Further studies including control groups are necessary to elucidate the impact of comorbidities such as hepatitis C or HIV on the development of osteoporosis in the haemophiliac.

Proliferating cholangiocytes: a neuroendocrine compartment in the diseased liver

In the last 15 years, the intrahepatic biliary tree has become the object of extensive studies, which highlighted the extraordinary biologic properties of cholangiocytes involved in bile formation, proliferation, injury repair, fibrosis, angiogenesis, and regulation of blood flow. Proliferation is a "typical" property of cholangiocytes and is key as a mechanism of repair responsible for maintaining the integrity of the biliary tree. Cholangiocyte proliferation occurs virtually in all pathologic conditions of liver injury where it is associated with inflammation, regeneration, and repair, thus conditioning the evolution of liver damage. Interestingly, proliferating cholangiocytes acquire the phenotype of neuroendocrine cells, and secrete different cytokines, growth factors, neuropeptides, and hormones, which represent potential mechanisms for cross talk with other liver cells. Many studies suggest the generation of a neuroendocrine compartment in the injured liver, mostly constituted by cells with cholangiocyte features, which functionally conditions the progression of liver disease. These insights on cholangiocyte pathophysiology will provide new potential strategies for the management of chronic liver diseases. The purpose of this review is to summarize the recent findings on the mechanisms regulating cholangiocyte proliferation and the significance of the neuroendocrine regulation of cholangiocyte biology.

Estrogens and the pathophysiology of the biliary tree

The scientific framework concerning estrogen effects on different tissues has expanded enormously during the last decades, when estrogen receptor (ER) subtypes were identified. Estrogens are not only essential for the female reproductive system, but they also control fundamental functions in other tissues including the cardiovascular system, bone, brain and liver. Recently, estrogens have been shown to target the biliary tree, where they modulate the proliferative and secretory activities of cholangiocytes, the epithelial cells lining bile ducts. By acting on both estrogen receptors (ER-α) and (ER-β) subtypes, and by activating either genomic or non-genomic pathways, estrogens play a key role in the complex loop of growth factors and cytokines, which modulates the proliferative response of cholangiocytes to damage. Specifically, estrogens activate intracellular signalling cascades [ERK1/2 (extracellular regulated kinases 1/2, PI3- kinase/AKT (phosphatidylinositol-3’ kinase/AKT)] typical of growth factors such as insulin like growth factor (IGF1), nerve growth factor (NGF) and vascular endothelial growth factor (VEGF), thus potentiating their action. In addition, estrogens stimulate the secretion of different growth factors in proliferating cholangiocytes. This review specifically deals with the recent advances related to the role and mechanisms by which estrogens modulate cholangiocyte functions in normal and pathological conditions.

Osteoporosis in primary biliary cirrhosis: a randomized trial of the efficacy and feasibility of estrogen/progestin

The optimal therapy for the prevention and treatment of osteoporosis in primary biliary cirrhosis (PBC) is unknown. Hormone replacement therapy (HRT) prevents osteoporosis, but may promote cholestasis. We performed a double-blind, randomized, placebo-controlled trial of transdermal estrogen/progestin in postmenopausal women with PBC. The 24-month study enrolled 31 patients, but trial uptake was limited and treatment arm dropout was significant. Placebo-treated patients had a higher percentage loss in femoral neck bone mineral density than actively treated patients (-3.76 +/- 1.37% versus 0.21 +/- 1.01%, respectively, P = .058). New fractures occurred in 2 patients on placebo, and in no patients on treatment. The mean monthly increase in bilirubin was not significantly different between groups, but individual data suggest HRT may worsen cholestasis. In conclusion, women with PBC have strong feelings about HRT, and recruitment for this intervention is difficult. Transdermal estrogen/progestin likely provides protection against bone loss in PBC patients, but may worsen cholestasis.

Extrahepatic manifestations of cholestatic liver diseases: pathogenesis and therapy

Pruritus, fatigue, and metabolic bone disease are frequent complications of cholestatic liver diseases, which can be quite distressing for the patient and can considerably reduce the quality of life. The molecular pathogenesis of these extrahepatic manifestations of cholestasis is poorly understood, and hypotheses to explain these symptoms are being discussed. This article provides treatment recommendations for the complications of cholestasis based on putative pathomechanisms and summarizes recent experimental and clinical data involving management options.

Extrahepatic manifestations of cholestatic liver diseases: pathogenesis and therapy

Pruritus, fatigue, and metabolic bone disease are frequent complications of cholestatic liver diseases, which can be quite distressing for the patient and can considerably reduce the quality of life. The molecular pathogenesis of these extrahepatic manifestations of cholestasis is poorly understood, and hypotheses to explain these symptoms are being discussed. This article provides treatment recommendations for the complications of cholestasis based on putative pathomechanisms and summarizes recent experimental and clinical data involving management options.

Osteoporosis in children and adolescents: etiology and management

Bone mass increases progressively during childhood, but mainly during adolescence when approximately 40% of total bone mass is accumulated. Peak bone mass is reached in late adolescence, and is a well recognised risk factor for osteoporosis later in life. Thus, increasing peak bone mass can prevent osteoporosis. The critical interpretation of bone mass measurements is a crucial factor for the diagnosis of osteopenia/osteoporosis in children and adolescents. To date, there are insufficient data to formally define osteopenia/osteoporosis in this patient group, and the guidelines used for adult patients are not applicable. In males and females aged <20 years the terminology 'low bone density for chronologic age' may be used if the Z-score is less than -2. For children and adolescents, this terminology is more appropriate than osteopenia/osteoporosis. Moreover, the T-score should not be used in children and adolescents. Many disorders, by various mechanisms, may affect the acquisition of bone mass during childhood and adolescence. Indeed, the number of disorders that have been identified as affecting bone mass in this age group is increasing as a consequence of the wide use of bone mass measurements. The increased survival of children and adolescents with chronic diseases or malignancies, as well as the use of some treatment regimens has resulted in an increase in the incidence of reduced bone mass in this age group. Experience in treating the various disorders associated with osteoporosis in childhood is limited at present. The first approach to osteoporosis management in children and adolescents should be aimed at treating the underlying disease. The use of bisphosphonates in children and adolescents with osteoporosis is increasing and their positive effect in improving bone mineral density is encouraging. Osteoporosis prevention is a key factor and it should begin in childhood. Pediatricians should have a fundamental role in the prevention of osteoporosis, suggesting strategies to achieve an optimal peak bone mass.

Effects of chronic liver disease on bone mineral density and bone metabolism markers in postmenopausal women

OBJECTIVES

Patients with chronic liver disease (CLD) have an increased prevalence of osteoporosis. However, there is limited information about the effects of end-stage liver disease on bone metabolism and bone mineral density values in postmenopausal women. The aim of this study was to investigate the effects of chronic liver disease on bone mineral density (BMD) and bone metabolism markers in postmenopausal women.

METHODS

We studied BMD by using dual-energy X-ray absorptiometry (DEXA), biochemical markers of bone turnover and calcium-parathyroid hormone (PTH)-Vitamin D axis in 22 postmenopausal women with CLD. Control group consisted of randomly recruited 30 healthy postmenopausal women.

RESULTS

Based on WHO criteria, the prevalence of osteoporosis was significantly higher in patients with CLD (72 versus 33%) compared to healthy postmenopausal women. Bone loss was more significant at the lumbar spine than femur in the study group. Urinary excretion of bone resorption marker deoxypyridinoline was increased significantly in patients with CLD. There were no significant differences in bone formation markers (osteocalcin and bone alkaline phosphatase) between the groups.

CONCLUSIONS

CLD increases the prevalence of osteoporosis in postmenopausal women, particularly in the lumbar spine. Increased bone resorption seems to be the main reason for osteoporosis in these patients. We suggest that treatment strategies should be improved in these women to protect them from subsequent fractures.

Alendronate improves bone mineral density in primary biliary cirrhosis: a randomized placebo-controlled trial

Bone loss is a well-recognized complication of primary biliary cirrhosis (PBC). Although it has been suggested that alendronate might improve bone mineral density (BMD) in PBC, no randomized placebo-controlled trial has been conducted. The primary aim of this study was to compare the effects of alendronate versus placebo on BMD and biochemical measurements of bone turnover in patients with PBC-associated bone loss. We conducted a double-blinded, randomized, placebo-controlled trial. Patients with a PBC and BMD t score of less than -1.5 were randomized to receive 70 mg per week of alendronate or placebo over 1 year. BMD of the lumbar spine and proximal femur were measured at entry and at 1 year. Changes from baseline in BMD and biochemical measurements of bone turnover were assessed. Thirty-four patients were enrolled. Seventeen patients were randomized to each arm. After 1 year, a significantly larger improvement (P = .005) in spine BMD was observed in the alendronate group (0.09 +/- 0.03 g/cm2 SD from baseline) compared with the placebo group (-0.003 +/- 0.02 g/cm2 SD from baseline). A larger improvement (P = .046) was also observed in the femoral BMD of alendronate patients versus placebo. BMD changes were independent of concomitant estrogen therapy. The rate of adverse effects was similar in both groups. In conclusion, in patients with PBC-related bone loss, alendronate significantly improves BMD compared with placebo. Although in this study oral alendronate appears to be well tolerated in patients with PBC, larger studies are needed to formally evaluate safety.

Bone mineral density and cytokine levels during interferon therapy in children with chronic hepatitis B: does interferon therapy prevent from osteoporosis?

BACKGROUND

Our aim was to determinate bone mineral density (BMD), levels of biochemical markers and cytokines in children with chronic hepatitis B treated with interferon (IFN)-alpha and to investigate effect of IFN-alpha therapy on these variables. To the best of our knowledge, this is first study carried out about BMD and cytokine levels in pediatric patients with chronic hepatitis B treated with IFN-alpha.

METHODS

BMD, levels of parathyroid hormone (PTH), osteocalcin, C-terminal cross-linking telopeptide of type I collagen (CTX), calcium, alkaline phosphates (ALP), cytokines as TNF-alpha, interleukin (IL)-1beta, IL-2r, IL-6, and IL-8 were studied in 54 children with chronic hepatitis B (4-15 years old) treated with interferon alone (n = 19) or in combination with lamivudine (n = 35) for six months and as controls in 50 age-matched healthy children.

RESULTS

There was no significant difference in respect to serum IL-1beta, TNF-alpha and osteocalcin levels while serum IL-2r (p = 0.002), IL-6 (p = 0.001), IL-8 (p = 0.013), PTH (p = 0.029), and CTX (p = 0.021) levels were higher in children with chronic hepatitis B than in healthy controls. BMD of femur neck (p = 0.012) and trochanter (p = 0.046) in patients were higher than in healthy controls. There was a statistically significant correlation between serum IL-1beta and osteocalcin (r = -0.355, p < 0.01); between serum IL-8 and CTX levels (r = 0.372, p = 0.01), and ALP (r = 0.361, p = 0.01); between serum ALP and femur neck BMD (r = 0.303, p = 0.05), and trochanter BMD (r = 0.365, p = 0.01); between spine BMD and IL-2R (r = -0.330, p < 0.05).

CONCLUSION

In conclusion, our study suggest that BMD of femur, serum IL-2r, IL-6, IL-8, PTH, and CTX levels were higher in children with chronic hepatitis B treated with IFN-alpha alone or combination with lamivudine than in healthy children. High femur BMD measurements found in patients may suggest that IFN-alpha therapy in children with chronic hepatitis B could contribute indirectly to prevent from hip osteoporosis. Additionally, further investigations on effects of IFN-alpha for bone structure in children should be performed in the future.

Is osteoporosis a peculiar association with primary biliary cirrhosis?

AIM

(1) To compare the prevalence of osteoporosis (t-score < or =-2.5 SD) between stage IV PBC patients, and two groups of age- and sex-matched controls: one with hepatitis C virus (HCV)-related cirrhosis, and the other one consisting of a group of healthy subjects from the general population; (2) to identify the main risk factors for the development of bone loss.

METHODS

Thirty-five stage IV PBC patients (mean age 52.5+/-10 years), 49 females with HCV-related cirrhosis (mean age 52.9+/-5.8 years) and 33 healthy females (mean age 51.8+/-2.22 years) were enrolled in the study. Bone metabolism was evaluated by measuring serum calcium corrected for serum albumin (Ca corr.), 25-hydroxy vitamin D (25-OH vit D), parathyroid hormone, osteocalcin. Bone mineral density (BMD) was assessed at the lumbar spine by dual-photon X-ray absorptiometry.

RESULTS

Osteoporosis was present in 5/35 PBC patients (14.2%) and in 7/49 HCV-related cirrhotic patients (14.3%), without any statistical difference between the two groups. Among healthy control subjects, none had osteoporosis. No difference was found between the three groups in serum parameters of bone metabolism. Univariate analysis showed that menopausal state and low BMI were significantly correlated with osteoporosis. Multivariate regression analysis showed that menopausal status, BMI <23, and old age were independent variables significantly correlated with osteoporosis.

CONCLUSION

PBC in itself has no negative influence on BMD. End-stage liver disease patients carry a disease-specific risk for osteoporosis, but have an effective risk of bone loss in relation to individual potential risk for each patient. A practical message should be taken into account, that is, every effort should be made to prevent osteoporosis when a patient has simple osteopenia, or if it is a woman in or near menopausal age.

Hepatic osteodystrophy: does the osteoprotegerin/receptor activator of nuclear factor-kB ligand system play a role?

Multiple factors can contribute to the development of osteodystrophy in patients with chronic liver disease (CLD). Recently, two new cytokines, osteoprotegerin (OPG) and the receptor activator of nuclear factor-kB ligand (RANKL), have been implicated in the pathogenesis of postmenopausal osteoporosis and other metabolic bone diseases. Therefore, the aim of our study was to evaluate bone metabolism, bone mineral density (BMD) and OPG/RANKL system in 65 male patients with CLD and in 65 healthy controls. Our patients showed lower BMD values than controls both at lumbar and femoral levels. Moreover, they had an unbalanced bone turnover with an increased resorption phase, as shown by high levels of urinary deoxypyridinoline and a decreased formation phase, as shown by the slightly, but significant, low levels of bone-alkaline phosphatase. Patients showed lower plasma levels of free-testosterone than controls and higher - although not significantly so - plasma levels of 17 beta-estradiol. Furthermore, patients with CLD had higher levels of sex hormone-binding globulin and OPG, and lower levels of 25-hydroxyvitamin D (25-HOD) and IGF-I than the control group, while RANKL levels were similar in the two groups. In conclusion, our data do not confirm the hypothesis that the OPG/RANKL system could exert a key role in the pathogenesis of hepatic osteodystrophy, but rather that the observed increase in OPG levels may represent either the result of the inflammatory process per se or a compensation for the observed enhanced bone resorption.

Osteoporose após transplante de órgãos sólidos

A osteoporose é uma complicação comum após os transplantes de rim, coração, fígado e pulmão. Os esquemas imunossupressores para evitar a rejeição do órgão enxertado após o transplante freqüentemente incluem glicocorticóides, ciclosporina A e tacrolimus, os quais possuem efeitos danosos sobre a homeostase mineral óssea, impostos a um esqueleto já comprometido. Outros fatores que provavelmente contribuem para a patogênese da osteoporose pós-transplante são deficiência de vitamina D, hiperparatireoidismo secundário e hipogonadismo. Medidas para avaliação da saúde óssea antes do transplante deveriam ser realizadas: densitometria mineral óssea, radiografia da coluna, avaliação do nível de vitamina D e dos hormônios gonadais. Todos os pacientes transplantados deveriam ser submetidos à profilaxia da perda óssea. Estudos clínicos sugerem que os bisfosfonatos são os agentes mais promissores para a prevenção e o tratamento da osteoporose pós-transplante.

Osteoprotegerin and RANKL in alcoholic liver cirrhosis

BACKGROUND/AIMS

The mechanisms leading to osteoporosis in alcoholic liver disease remain poorly understood. Recently identified soluble circulating osteoprotegerin (OPG), is the osteoclastogenesis inhibitory factor. It acts as a decoy receptor for osteoclast activating factor, receptor activator of nuclear factor-kappaB ligand (RANKL), and impairs osteoclast function. The aim of our study was to investigate the OPG/RANKL system in alcoholic cirrhotic patients and their correlation with biochemical marker of bone turnover.

PATIENTS AND METHODS

Serum OPG, RANKL, osteocalcin (OC), C-terminal cross-linking telopeptide of type I collagen (CTX-I), bone alkaline phosphatase activity (bALP), and urinary hydroxyproline were measured in 30 patients with alcoholic cirrhosis, and in 20 age- and sex-matched healthy controls.

RESULTS

OPG levels were significantly increased in patients with alcoholic cirrhosis compared with healthy subjects (5.9 pmol/l, range 2.7-9.0 vs 4.1 pmol/l, range 1.2-6.6; P < 0.001). RANKL levels were significantly higher in patients with cirrhosis (0.48 pmol/l, range 0.01-1.34) than in healthy subjects (0.11 pmol/l, range 0.01-0.90). There was a positive correlation between serum OPG and RANKL (r = 0.37; P < 0.001), bALP (r = 0.66; P < 0.001) and urinary hydroxyproline (r = 0.51; P < 0.05) but not with OC and CTX-I.

CONCLUSIONS

OPG might partly represent a compensating mechanism to the negative balance of bone remodelling in patients with alcoholic cirrhosis.