Osteoporosis in liver disease: pathogenesis and management

Osteoporosis in chronic liver disease

Osteoporosis is a frequent complication in patients with chronic liver disease, especially in end-stages and in chronic cholestasis, in addition to non-alcoholic fatty liver disease, haemochromatosis and alcoholism. Mechanisms underlying osteoporosis are poorly understood, but osteoporosis mainly results from low bone formation. In this setting, sclerostin, a key regulator of the Wnt/β-catenin signalling pathway which regulates bone formation, in addition to the effects of the retained substances of cholestasis such as bilirubin and bile acids on osteoblastic cells, may influence the decreased bone formation in chronic cholestasis. Similarly, the damaging effects of iron and alcohol on osteoblastic cells may partially explain bone disease in haemochromatosis and alcoholism. A role for proinflammatory cytokines has been proposed in different conditions. Increased bone resorption may occur in cholestatic women with advanced disease. Low vitamin D, poor nutrition and hypogonadism, may be contributing factors to the full picture of bone disorders in chronic liver disease.

25-Hydroxyvitamin D levels and bone mineral density evaluation in patients with cholecystectomy: a case-control study

This study compared the 25-hyrdoxyvitamin (OH) D and bone mineral density (BMD) values of patients with and without cholecystectomy. Although 25(OH) D levels were significantly lower in the cholecystectomy group (12.1 ± 6.2 vs. 15.6 ± 6.6 ng/mL), no significant difference was observed between the groups in terms of BMD measurements.

INTRODUCTION

Although 25 (OH) D levels were studied and found to be lower in patients with cholecystectomy, the data is scarce as regards the BMD. Therefore, the aim of this study was to compare the 25(OH) D and BMD values of patients with cholecystectomy and without cholecystectomy.

METHODS

This study was a single-center and case-control trial. The cholecystectomy group comprised the patients with a history of cholecystectomy. In addition, a healthy control group without history of cholecystectomy was defined. All patients were selected consecutively from the patients who admitted to the outpatient clinics of physical and rehabilitation medicine or internal medicine between the June 2016 and August 2016. The patients were ambulatory and did not receive any osteoporosis treatment before. Chemiluminescence microparticle immunoassay method was used for 25(OH) D measurements. Dual-energy X-ray absorptiometry was used for the BMD evaluations.

RESULTS

There were 46 patients in the cholecystectomy group with a mean age of 58.6 ± 14.1 years and 64 patients in the control group with a mean age of 59.2 ± 13.3 years. Although 25(OH) D levels were significantly lower in the cholecystectomy group (12.1 ± 6.2 vs. 15.6 ± 6.6 ng/mL) (p =  0.010), no significant difference was observed between the groups in terms of BMD measurements (p > 0.05). While there was a weak positive correlation between the BMI and BMD measurements (all p < 0.05), linear regression analyses showed that the models were not valid (femoral neck R = 0.092; femur total R = 0.170; and lumbar total R = 0.199). No significant difference was observed between the BMD measurements and time after cholecystectomy in the cholecystectomy group (p > 0.05).

CONCLUSION

In the light of our results, cholecystectomy patients seem to have lower level of 25(OH) D levels in comparison with healthy subjects, but both groups have similar BMD values. Further studies in cohort designs taking into account the bone formation and resorption markers are awaited.

Hepatitis C virus infection and risk of osteoporotic fracture: A systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Hepatitis C virus (HCV) infection is one of the most common causes of chronic liver disease. Several epidemiologic studies have suggested that patients with HCV infection might have a higher risk of osteoporotic fracture. However, the data are inconclusive. This systematic review and meta-analysis was conducted with the aims to summarize all available evidence.

METHODS

A literature search was performed using MEDLINE and EMBASE database from inception to June 2016. Studies that reported relative risks, odd ratios, or hazard ratios comparing the risk of osteoporotic fracture among HCV-infected patients versus subjects without HCV infection were included. Pooled risk ratio (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Three studies with 362,285 participants met our eligibility criteria and were included in analysis. We found a significantly higher risk of osteoporotic fracture among patients with HCV infection with RR of 1.53 (95% CI 1.09 to 2.14).

CONCLUSIONS

Our study demonstrated an increased risk of osteoporotic fracture among HCV-infected patients. Further studies are required to clarify how this risk should be addressed in clinical practice.

Reduced Serum IGF-1 Associated With Hepatic Osteodystrophy Is a Main Determinant of Low Cortical but Not Trabecular Bone Mass

Hepatic osteodystrophy is multifactorial in its pathogenesis. Numerous studies have shown that impairments of the hepatic growth hormone/insulin-like growth factor-1 axis (GH/IGF-1) are common in patients with non-alcoholic fatty liver disease, chronic viral hepatitis, liver cirrhosis, and chronic cholestatic liver disease. Moreover, these conditions are also associated with low bone mineral density (BMD) and greater fracture risk, particularly in cortical bone sites. Hence, we addressed whether disruptions in the GH/IGF-1 axis were causally related to the low bone mass in states of chronic liver disease using a mouse model of liver-specific GH-receptor (GHR) gene deletion (Li-GHRKO). These mice exhibit chronic hepatic steatosis, local inflammation, and reduced BMD. We then employed a crossing strategy to restore liver production of IGF-1 via hepatic IGF-1 transgene (HIT). The resultant Li-GHRKO-HIT mouse model allowed us to dissect the roles of liver-derived IGF-1 in the pathogenesis of osteodystrophy during liver disease. We found that hepatic IGF-1 restored cortical bone acquisition, microarchitecture, and mechanical properties during growth in Li-GHRKO-HIT mice, which was maintained during aging. However, trabecular bone volume was not restored in the Li-GHRKO-HIT mice. We found increased bone resorption indices in vivo as well as increased basal reactive oxygen species and increased mitochondrial stress in osteoblast cultures from Li-GHRKO and the Li-GHRKO-HIT compared with control mice. Changes in systemic markers such as inflammatory cytokines, osteoprotegerin, osteopontin, parathyroid hormone, osteocalcin, or carboxy-terminal collagen cross-links could not fully account for the diminished trabecular bone in the Li-GHRKO-HIT mice. Thus, the reduced serum IGF-1 associated with hepatic osteodystrophy is a main determinant of low cortical but not trabecular bone mass. © 2017 American Society for Bone and Mineral Research.

Bone mineral density loss in patients with cirrhosis

BACKGROUND/AIMS

Evidence of increased risk of osteoporosis and osteopenia in chronic liver disease and cirrhosis is inconsistent. This study aims to investigate this relationship and to identify the predictors of increased loss of bone mineral density in Saudi patients.

PATIENTS AND METHODS

One hundred and sixty-four patients and controls who are age and gender matched, were included in this study with 1:1 ratio. Patients' included in this study were adults with confirmed liver cirrhosis. Bone mineral densitometry (BMD) at both lumbar spine (LS) and femoral neck (FN) were collected for both groups. Univariate and multivariate regression analyses were performed to identify predictors of BMD loss.

RESULTS

Results showed that cirrhotic patients are at higher risk of developing osteoporosis or osteopenia at LS (OR 2.23, 95% CI [1.19-4.19], P = 0.01) but not at FN, when compared to control sample. Patients with cirrhosis were found to have lower vitamin D and PTH levels (P = 0.0005) and (P = 0.006), respectively. Of the possible predictors tested (gender, age, body mass index [BMI], phosphorus, calcium, parathyroid hormone (PTH), vitamin D, and Model for End Stage Liver Disease [MELD] score), female gender was the main predictor of loss of BMD at LS only (OR 4.80, 95% CI [1.47-15.73], P = 0.01).

CONCLUSIONS

The study showed that cirrhotic patients are at increased susceptibility of having decreased BMD, particularly at the LS and it highlights the need for preventive measures, especially for female patients.

Treatment Response and Outcome with Two Different Prednisolone Regimens in Autoimmune Hepatitis

BACKGROUND

Beyond available guidelines, therapy of autoimmune hepatitis (AIH) shows wide variation among physicians. We compared two regimens for treatment naive AIH: one recommended protocol with an initial prednisolone dose of 30 mg/day and our own 40 mg/day prednisolone with a slow dose tapering protocol. We analyzed the safety, response rates, and outcomes for two groups of treated patients.

PATIENTS AND METHODS

We retrospectively evaluated data of 71 AIH patients including, group I (n = 32, prednisone 30 mg/day) and group II (n = 39, prednisone 40 mg/day). All patients also received azathioprine.

RESULTS

The frequency of complete biochemical response was significantly higher in group II than in group I (69.2 vs. 43.8%, p = 0.031) after 3 months of therapy, but not after 6 and 12 months (79.5 vs. 59.4%, p = 0.065 and 89.5 vs. 80.6%, p = 0.30). In patients with severe interface hepatitis, the complete response rates were significantly higher in group II than in group I after 3 (63.6 vs. 23.1%, p = 0.02) and 6 months (72.7 vs. 38.5%, p = 0.046), but not after 12 months of therapy (86.4 vs. 69.2%, p = 0.221). Relapses were observed in 50% of group I and in 35.9% of group II during maintenance therapy (p = 0.23). Overall survival was significantly better in group II than in group I (100 vs. 87.5%, log-rank, p = 0.048). No severe steroid-related side effects were observed in either group.

CONCLUSIONS

Our real-world experience suggests that an initial prednisolone dose of 40 mg/day with a slower tapering protocol induces earlier biochemical response, tends to result in less relapses during maintenance, and is associated with a better disease outcome.

Association between primary biliary cholangitis and osteoporosis: meta-analysis

The relationship between primary biliary cholangitis (PBC, previously termed primary biliary cirrhosis) and risks of osteoporosis remains controversial. This meta-analysis was designed to comprehensively analyze the association between PBC and osteoporosis. We conducted a systematic literature search of the PubMed, EMBASE, and Web of Science. Either fixed or random effects models were applied to assess bone mineral density (BMD), osteoporosis rates, and fractures in PBC patients and normal controls. A total of eight studies were included (including 1643 PBC patients and 10,921 controls). PBC patients had a relative risk (RR) of 2.79 (95% CI 1.26 to 6.16) for the development of osteoporosis, lower lumbar spine BMD (95% CI - 0.13 to - 0.04, P = 0.0002), hip BMD (95% CI - 0.13 to - 0.03, P = 0.002), and lumbar spine t score (95% CI - 1.69 to - 1.02, P < 0.00001) than controls. Moreover, PBC patients had an OR of 1.86 (95%CI 1.54 to 2.24, P < 0.00001) for the development of fractures. Collectively, this meta-analysis indicates that PBC patients were more likely to suffer from osteoporosis. Given the limited literature available, better designed and larger scale primary studies will be required to confirm our conclusion.

Effects of long-term oral administration of methimazole on femur and tibia properties in male Wistar rats

Physiological concentrations of thyroid hormones are crucial for skeletal growth and development, physiological bone turnover and bone homeostasis maintenance. Methimazole (1-methyl-2-mercaptoimidazole) is an antithyroid drug used for the treatment of the hyperthyroidism in humans and animals. The aim of the study was to determine effects of long-term oral methimazole treatment in male Wistar rats on biochemical bone metabolism markers, as well as morphological, geometric, densitometric and mechanical properties of femur and tibia. Experimental rats were subjected to 90-day-long oral treatment with 0.05% water solution of methimazole and were kept under identical environmental conditions and received the same diet ad libitum as the control group. Serum concentration of osteocalcin (OC) and C-terminal telopeptides of type I collagen (CTX-I) was determined. Femur and tibia were evaluated using quantitative computed tomography (QCT), peripheral QCT (pQCT) and three-point bending test. Final body weight of the experimental group was significantly decreased by 30% (P=0.01). Methimazole treatment significantly decreased serum OC concentration by 21% (P=0.02) and increased CTX-I concentration by 17% (P=0.06). Methimazole decreased morphological, geometric and densitometric parameters of femur and tibia in rats. Mechanical evaluation of bones has shown significantly decreased maximum elastic strength and ultimate strength of femur in rats treated with methimazole by 36% and 40% when compared to the control group (P<0.05). In conclusion, this study has shown that long-term treatment with methimazole inhibits bone formation and accelerates bone resorption processes. The observed negative effects of methimazole treatment on body weight gain and skeletal properties may be considered as additional possible side effects in living organisms to those reported in the previous studies. It may be suggested that long-term antithyroid treatment should be combined with prevention of the negative effects of methimazole on bone tissue and whole body metabolism.

Cholestatic Liver Injury: Care of Patients With Primary Biliary Cholangitis or Primary Sclerosing Cholangitis

The most common causes of chronic cholestatic liver disease are primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). Both disease processes are characterized by a destruction of intrahepatic and/or extrahepatic biliary ducts. The etiology is not entirely clear; however, there is an underlying autoimmune component contributing to both disease processes. Although PBC and PSC are often diagnosed and managed in the outpatient setting, in some instances, a patient may have jaundice, fatigue, and pruritus requiring evaluation and determination of the cholestatic cause. Patients with PSC should be monitored for evidence of cholangiocarcinoma, colon cancer, and gallbladder polyps as they are at an increased risk of malignant neoplasms. Liver transplant has the potential for improving quality of life, although disease recurrence is a risk.