Osteodystrophy in Cholestatic Liver Diseases Is Attenuated by Anti-γ-Glutamyl Transpeptidase Antibody

The dark side of gamma-glutamyltransferase (GGT): Pathogenic effects of an 'antioxidant' enzyme

Having long been regarded as just a member in the cellular antioxidant systems, as well as a clinical biomarker of hepatobiliary diseases and alcohol abuse, gamma-glutamyltransferase (GGT) enzyme activity has been highlighted by more recent research as a critical factor in modulation of redox equilibria within the cell and in its surroundings. Moreover, due to the prooxidant reactions which can originate during its metabolic function in selected conditions, experimental and clinical studies are increasingly involving GGT in the pathogenesis of several important disease conditions, such as atherosclerosis, cardiovascular diseases, cancer, lung inflammation, neuroinflammation and bone disorders. The present article is an overview of the laboratory findings that have prompted an evolution in interpretation of the significance of GGT in human pathophysiology.

Review: Pathogenesis of cholestatic liver diseases

Cholestatic liver diseases (CLD) begin to develop after an impairment of bile flow start to affect the biliary tree. Cholangiocytes actively participate in the liver response to injury and repair and the intensity of this reaction is a determinant factor for the development of CLD. Progressive cholangiopathies may ultimately lead to end-stage liver disease requiring at the end orthotopic liver transplantation. This narrative review will discuss cholangiocyte biology and pathogenesis mechanisms involved in four intrahepatic CLD: Primary biliary cholangitis, primary sclerosing cholangitis, cystic fibrosis involving the liver, and polycystic liver disease.

Chronic Liver Disease Patients have Worse Outcomes and Increased Postoperative Complications After Orthopedic Fractures

INTRODUCTION

Cirrhotic patients are at a higher risk for sustaining orthopedic fractures with a reported prevalence of 5% to 20%. Cirrhosis also affects wound healing and bleeding risk, and hence, impacts the postoperative outcomes after fracture repair. However, there is limited data available on the postoperative risk factors and clinical outcomes of fractures in patients with chronic liver disease (CLD).

METHODS

Data from the National Inpatient Sample for the years 2012 to 2015 were analyzed. Patients were identified using ICD-9 codes for any fracture. ICD-9 codes for CLD were used to categorize patients into CLD and non-CLD groups. Primary outcomes included inpatient mortality, length of stay (LOS), and total hospital charges. Secondary outcomes included complications such as postoperative infection, prosthetic failure, bleeding, and improper wound healing.

RESULTS

A total of 931,193 patient encounters for orthopedic fractures were identified and divided into 17,388 with CLD and 913,806 without CLD (non-CLD). The inpatient mortality in patients with CLD was almost twice that of non-CLD patients (odds ratio, 1.95; 95% confidence interval, 1.8-2.1). Patients with CLD also had a longer mean LOS at 7.4±8.6 days versus 5.6±7.2 days (P<0.001) and higher total hospital charges at $76,198±99,494 versus $64,294±95,673 (P<0.001). CLD patients also had higher rates of infections, improper wound healing, and bleeding.

DISCUSSION

In this large retrospective study, CLD patients with fractures had significantly higher mortality, LOS and hospital charges. These findings correlate with the higher rates of infection, bleeding, and poorer wound healing in this population. Increased clinician awareness of these risks is a key to improving the care of CLD patients.

Risk of secondary osteoporosis due to lobular cholestasis in non-cirrhotic primary biliary cholangitis

BACKGROUND AND AIM

It remains unclear whether primary biliary cholangitis (PBC) represents a risk factor for secondary osteoporosis.

METHODS

A case-control study was conducted to examine bone mineral density and bone turnover markers in middle-aged postmenopausal PBC patients without liver cirrhosis. We compared the incidence of low bone mineral density between propensity-score matched subgroups of PBC patients and healthy controls and investigated the mechanisms underlying unbalanced bone turnover in terms of the associations between bone turnover markers and PBC-specific histological findings.

RESULT

Our analysis included 128 consecutive PBC patients, all postmenopausal women aged in their 50s or 60s, without liver cirrhosis or fragility fracture at the time of PBC diagnosis. The prevalence of osteoporosis was significantly higher in the PBC group than in the control group (26% vs 10%, P = 0.015, the Fisher exact probability test). In most PBC patients (95%), the level of bone-specific alkaline phosphatase was above the normal range, indicating increased bone formation. On the other hand, the urine type I collagen-cross-linked N-telopeptide showed variable levels among our PBC patients, indicating unbalanced bone resorption. Advanced fibrosis was associated with low bone turnover. Lobular cholestasis, evaluated as aberrant keratin 7 expression in hepatocytes, showed significant negative correlations with bone formation and resorption, indicating low bone turnover.

CONCLUSION

Our results show that, compared with healthy controls, even non-cirrhotic PBC patients have significantly higher risk of osteoporosis. Moreover, lobular cholestasis was associated with low bone turnover, suggesting this feature of PBC may itself cause secondary osteoporosis in PBC patients.

Anti-steatotic and anti-fibrotic effects of the KCa3.1 channel inhibitor, Senicapoc, in non-alcoholic liver disease

AIM

To evaluate a calcium activated potassium channel (KCa3.1) inhibitor attenuates liver disease in models of non-alcoholic fatty liver disease (NAFLD).

METHODS

We have performed a series of in vitro and in vivo studies using the KCa3.1 channel inhibitor, Senicapoc. Efficacy studies of Senicapoc were conducted in toxin-, thioacetamide (TAA) and high fat diet (HFD)-induced models of liver fibrosis in rats. Efficacy and pharmacodynamic effects of Senicapoc was determined through biomarkers of apoptosis, inflammation, steatosis and fibrosis.

RESULTS

Upregulation of KCa3.1 expression was recorded in TAA-induced and high fat diet-induced liver disease. Treatment with Senicapoc decreased palmitic acid-driven HepG2 cell death. (P < 0.05 vs control) supporting the finding that Senicapoc reduces lipid-driven apoptosis in HepG2 cell cultures. In animals fed a HFD for 6 wk, co-treatment with Senicapoc, (1) reduced non-alcoholic fatty liver disease (NAFLD) activity score (NAS) (0-8 scale), (2) decreased steatosis and (3) decreased hepatic lipid content (Oil Red O, P < 0.05 vs vehicle). Randomization of TAA animals and HFD fed animals to Senicapoc was associated with a decrease in liver fibrosis as evidenced by hydroxyproline and Masson’s trichrome staining (P < 0.05 vs vehicle). These results demonstrated that Senicapoc mitigates both steatosis and fibrosis in liver fibrosis models.

CONCLUSION

These data suggest that Senicapoc interrupts more than one node in progressive fatty liver disease by its anti-steatotic and anti-fibrotic activities, serving as a double-edged therapeutic sword.