[Plasma leptin levels in patients with primary biliary cirrhosis and their relationship with degree of fibrosis]

The relationship between disease activity and UDCA response criteria in primary biliary cholangitis: A cohort study

BACKGROUND

Uncertainty exists about how best to identify primary biliary cholangitis (PBC) patients who would benefit from second-line therapy. Existing, purely clinical, ursodeoxycholic acid (UDCA) response criteria accept degrees of liver biochemistry abnormality in responding patients, emerging data, however, suggest that any degree of ongoing abnormality may, in fact, be associated with an increased risk of adverse outcomes. This cohort study explores the link between response status, the biology of high-risk disease and its implications for clinical practice.

METHODS

Proteomics, exploring 19 markers previously identified as remaining elevated in PBC following UDCA therapy, were performed on 400 serum samples, from participants previously recruited to the UK-PBC Nested Cohort between 2014 and 2019. All participants had an established diagnosis of PBC and were taking therapeutic doses of UDCA for greater than 12 months. UDCA response status was assessed using Paris 1, Paris 2 and the POISE criteria, with additional analyses using normal liver blood tests stratified by bilirubin level. Statistical analysis using parametric t tests and 1-way ANOVA.

FINDINGS

Disease markers were statistically significantly higher in UDCA non-responders than in responders for all the UDCA response criteria, suggesting a meaningful link between biochemical disease status and disease mechanism. For each of the criteria, however, marker levels were also statistically significantly higher in responders with ongoing liver function test abnormality compared to those who had normalised their liver biochemistry. IL-4RA, IL-18-R1, CXCL11, 9 and 10, CD163 and ACE2 were consistently elevated across all responder groups with ongoing LFT abnormality. No statistically significant differences occurred between markers in normal LFT groups stratified by bilirubin level.

INTERPRETATION

This study provides evidence that any ongoing elevation in alkaline phosphatase levels in PBC after UDCA therapy is associated with some degree of ongoing disease activity. There was no difference in activity between patients with normal LFT when stratified by bilirubin. These findings suggest that if our goal is to completely control disease activity in PBC, then normalisation of alkaline phosphatase and bilirubin should be the treatment target. This would also simplify messaging around goals of therapy in PBC, benefiting both patients and clinicians.

FUNDING

Funding by the UK Medical Research Council (Stratified Medicine Programme) and an independent research grant by Pfizer. The study funders played no role in the study design, data collection, data analyses, data interpretation or manuscript writing.

Predictive and Diagnostic Value of Serum Adipokines in Pregnant Women with Intrahepatic Cholestasis

The objective of this study was to assess the value of serum leptin, adiponectin, apelin, and ghrelin as biomarkers for the prediction and diagnosis of intra-hepatic cholestasis (ICP). This prospective study included pregnant women in the third trimester of pregnancy: 63 with ICP, 48 and 15 of whom had mild and severe disease, respectively, and 32 as controls. ICP women had increased median levels of serum leptin, adiponectin, apelin, and ghrelin compared to the controls (p < 0.05). These biomarkers meaningfully changed regarding the severity of ICP: While leptin was reduced, apelin and ghrelin were increased, and adiponectin was increased somewhat. To predict and diagnose ICP, the predictive values of serum leptin, adiponectin, and apelin need to be accepted as comparable, with moderate to high sensitivity and specificity; however, the predictive value of serum ghrelin was somewhat lower. More research is needed to clarify the potential properties of adipokines to gain acceptance as a predictive or diagnostic biomarker for ICP.

Roles of Adipokines in Digestive Diseases: Markers of Inflammation, Metabolic Alteration and Disease Progression

Adipose tissue is a highly dynamic endocrine tissue and constitutes a central node in the interorgan crosstalk network through adipokines, which cause pleiotropic effects, including the modulation of angiogenesis, metabolism, and inflammation. Specifically, digestive cancers grow anatomically near adipose tissue. During their interaction with cancer cells, adipocytes are reprogrammed into cancer-associated adipocytes and secrete adipokines to affect tumor cells. Moreover, the liver is the central metabolic hub. Adipose tissue and the liver cooperatively regulate whole-body energy homeostasis via adipokines. Obesity, the excessive accumulation of adipose tissue due to hyperplasia and hypertrophy, is currently considered a global epidemic and is related to low-grade systemic inflammation characterized by altered adipokine regulation. Obesity-related digestive diseases, including gastroesophageal reflux disease, Barrett’s esophagus, esophageal cancer, colon polyps and cancer, non-alcoholic fatty liver disease, viral hepatitis-related diseases, cholelithiasis, gallbladder cancer, cholangiocarcinoma, pancreatic cancer, and diabetes, might cause specific alterations in adipokine profiles. These patterns and associated bases potentially contribute to the identification of prognostic biomarkers and therapeutic approaches for the associated digestive diseases. This review highlights important findings about altered adipokine profiles relevant to digestive diseases, including hepatic, pancreatic, gastrointestinal, and biliary tract diseases, with a perspective on clinical implications and mechanistic explorations.

Osteoporosis in liver disease: pathogenesis and management

Osteoporosis affects a substantial proportion of patients with chronic liver disease. Pathologic fracture in osteoporosis significantly affects quality of life and life expectancy. By some estimates, 40% of patients with chronic liver disease may experience osteoporotic fracture. In this study we review the pathogenesis, diagnosis and treatment of specific liver disease entities and their relation to osteoporosis.

Primary biliary cirrhosis: Clinical and laboratory criteria for its diagnosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic granulomatous, and destructive inflammatory lesion of small intralobular and septal bile ducts, which is likely to be caused by an autoimmune mechanism with a the presence of serum antimitochondrial antibodies and a potential tendency to progress to cirrhosis. Despite the fact that the etiology of this disease has been unknown so far, there has been a considerable body of scientific evidence that can reveal the clinical and laboratory signs of PBC and the individual components of its pathogenesis and elaborate diagnostic criteria for the disease and its symptomatic therapy. Deficiencies in autoimmune tolerance are critical factors for the initiation and perpetuation of the disease. The purpose of this review is to summarize the data available in the literature and the author’s findings on clinical and laboratory criteria for the diagnosis of PBC. This review describes the major clinical manifestations of the disease and the mechanisms of its development. It presents the immunological, biochemical, and morphological signs of PBC and their significance for its diagnosis. A great deal of novel scientific evidence for the problem of PBC has been accumulated. However, the inadequate efficiency of therapy for the disease lends impetus to the quest for its etiological factors and to further investigations of its pathogenetic mechanisms and, on this basis, to searches for new methods for its early diagnosis.

Curcumin targets multiple pathways to halt hepatic stellate cell activation: updated mechanisms in vitro and in vivo

Nonalcoholic steatohepatitis (NASH) is the advanced form of nonalcoholic fatty liver disease, which is often accompanied by obese and/or type II diabetes mellitus. Approximately one-third of NASH patients develop hepatic fibrosis. Hepatic stellate cells are the major effector cells during liver fibrogenesis. Advanced liver fibrosis usually proceeds to cirrhosis and even hepatocellular carcinoma, leading to liver failure, portal hypertension and even death. Currently, there are no approved agents for treatment and prevention of liver fibrosis in human beings. Curcumin, the principal curcuminoid of turmeric, has been reported to show antitumor, antioxidant, and anti-inflammatory properties both in in vitro and in vivo systems. Accumulating data shows that curcumin plays a critical role in combating liver fibrogenesis. This review will discuss the inhibitory roles of curcumin and update the underlying mechanisms by which curcumin targets in inhibiting hepatic stellate cell activation.

Osteoporosis in primary biliary cirrhosis of the liver

Osteoporosis is a metabolic bone disease associated with a reduction in bone mass and deterioration of bone architecture, leading to increased fragility and subsequent low-trauma fractures in the vertebral column, hip, forearm and other bones. In literature, metabolic bone diseases such as osteoporosis and osteomalacia have been recognised as a complication of chronic liver disease, although the mechanisms of this association remain unclear. An increasing body of research data indicates a strong relationship between osteoporosis and primary biliary cirrhosis (PBC), which mainly results from early diagnosis of the disease, usually when it is still asymptomatic. The incidence of osteoporosis in PBC ranges from 20% to 44% and increases with the progression of the disease. Similarly, the incidence of bone fractures is high in this group of patients (10-20%). In this article, current knowledge on risk factors, pathogenesis, diagnosis and treatment of osteoporosis in PBC is reviewed.

p38 mitogen-activated protein kinase and liver X receptor-α mediate the leptin effect on sterol regulatory element binding protein-1c expression in hepatic stellate cells

Leptin, a key hormone in regulating energy homeostasis, is mainly produced by adipocytes. Cogent evidence indicates a unique role of leptin in the promotion of liver fibrosis. Hepatic stellate cell (HSC) activation is a pivotal step in the process of liver fibrosis. Sterol regulatory element binding protein (SREBP)-1c, a critical transcription factor for lipid synthesis and adipocyte differentiation, functions as a key transcription factor in inhibition of HSC activation. SREBP-1c is highly expressed in quiescent HSCs and downregulated upon HSC activation. The aim of this study is to examine the effect of leptin on SREBP-1c gene expression in HSCs in vitro and in vivo and elucidate the underlying mechanisms. The results of the present study demonstrated that leptin strongly inhibited SREBP-1c expression in HSCs in vivo and in vitro. p38 MAPK was involved in leptin regulation of SREBP-1c expression in cultured HSCs. Leptin-induced activation of p38 MAPK led to the decreases in liver X receptor (LXR)-α protein level, activity and its binding to the SREBP-1c promoter, which caused the downregulation of SREBP-1c expression. Moreover, leptin inhibition of SREBP-1c expression via p38 MAPK increased the expression of alpha1(I) collagen in HSCs. Our results might provide new insights into the mechanisms of the unique role of leptin in the development of liver fibrosis and might have potential implications for clarifying the molecular mechanisms underlying liver fibrosis in diseases in which circulating leptin levels are elevated such as nonalcoholic steatohepatitis, type 2 diabetes mellitus and alcoholic cirrhosis.

Curcumin protects hepatic stellate cells against leptin-induced activation in vitro by accumulating intracellular lipids

Obesity and type II diabetes mellitus are often associated with hyperleptinemia and commonly accompanied by nonalcoholic steatohepatitis, which could cause hepatic fibrosis. During hepatic fibrogenesis, the major effectors hepatic stellate cells (HSCs) become active, coupling with depletion of cellular lipid droplets and downexpression of genes relevant to lipid accumulation. Accumulating evidence supports the proposal that recovering the accumulation of lipids would inhibit HSC activation. We recently reported that leptin stimulated HSC activation, which was eliminated by curcumin, a phytochemical from turmeric. The current study was designed to explore the underlying mechanisms, focusing on their effects on the level of intracellular lipids. We hypothesized that one of the mechanisms by which leptin stimulated HSC activation was to stimulate the depletion of intracellular lipids, which could be abrogated by curcumin by inducing expression of genes relevant to lipid accumulation. In this report, we observed that leptin dose dependently reduced levels of intracellular fatty acids and triglycerides in passaged HSCs, which were eliminated by curcumin. The phytochemical abrogated the impact of leptin on inhibiting the activity of AMP-activated protein kinase (AMPK) in HSCs in vitro. The activation of AMPK resulted in inducing expression of genes relevant to lipid accumulation and increasing intracellular lipids in HSCs in vitro. In summary, curcumin eliminated stimulatory effects of leptin on HSC activation and increased AMPK activity, leading to inducing expression of genes relevant to lipid accumulation and elevating the level of intracellular lipids. These results provide novel insights into mechanisms of curcumin in inhibiting leptin-induced HSC activation.

Curcumin eliminates leptin's effects on hepatic stellate cell activation via interrupting leptin signaling

Nonalcoholic steatohepatitis (NASH) is commonly found in patients with obesity and is often accompanied with abnormally elevated levels of plasma leptin, i.e. hyperleptinemia. A relatively high population of NASH patients develops hepatic fibrosis, even cirrhosis. Hepatic stellate cells (HSCs) are the major effector cells during liver fibrogenesis and could be activated by leptin. The antioxidant curcumin, a phytochemical from turmeric, has been shown to suppress HSC activation in vitro and in vivo. This project is to evaluate the effect of curcumin on leptin-induced HSC activation and to elucidate the underlying mechanisms. We hypothesize that curcumin abrogates the stimulatory effect of leptin on HSC activation by interrupting leptin signaling and attenuating leptin-induced oxidative stress. Curcumin eliminates the stimulatory effects of leptin on regulating expression of genes closely relevant to HSC activation. Curcumin interrupts leptin signaling by reducing phosphorylation levels of leptin receptor (Ob-R) and its downstream intermediators. In addition, curcumin suppresses gene expression of Ob-R in HSCs, which requires the activation of endogenous peroxisome proliferator-activated receptor-gamma and de novo synthesis of glutathione. In conclusion, our results demonstrate that curcumin abrogates the stimulatory effect of leptin on HSC activation in vitro by reducing the phosphorylation level of Ob-R, stimulating peroxisome proliferator-activated receptor-gamma activity, and attenuating oxidative stress, leading to the suppression of Ob-R gene expression and interruption of leptin signaling. These results provide novel insights into therapeutic mechanisms of curcumin in inhibiting HSC activation and intervening liver fibrogenesis associated with hyperleptinemia in NASH patients.

[Fibrogenesis and inflammatory bowel disease]

A substantial proportion of patients with Crohn's disease develops intestinal stenosis due to anomalous fiber deposits. These patients frequently require resection of the affected segment. Despite its evident clinical significance, intestinal fibrogenesis has received little attention in comparison with research into hepatic, pulmonary, renal or cutaneous fibrosis. There seems to be a certain genetic predisposition to developing intestinal fibrosis. A meta-analysis has demonstrated that the three main variants of the NOD2/CARD15 gene are associated with this complication. In Crohn's disease, a series of alterations in collagen synthesis, expression of various pro- and anti-fibrogenic factors and intestinal fibroblast function have been described in the last few years. More recently, the development of intestinal fibrosis has been attenuated in several experimental models. Nevertheless, further studies are required to improve our understanding of intestinal fibrogenesis and to develop effective strategies for its prevention and treatment.

Concept on the pathogenesis and treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an organ-specific autoimmune disease that predominantly affects women and is characterized by chronic, progressive destruction of small intrahepatic bile ducts with portal inflammation and ultimately fibrosis, leading to liver failure in the absence of treatment. Little is known about the etiology of PBC. PBC is characterized by anti-mitochondrial antibodies and destruction of intra-hepatic bile ducts. The serologic hallmark of PBC is the presence of auto-antibodies to mitochondria, especially to the E2 component of the pyruvate dehydrogenase complex (PDC). Current theories on the pathogenesis of PBC favor the hypothesis that the disease develops as a result of an inappropriate immune response following stimulation by an environmental or infectious agent. Some reports suggest that xenobiotics and viral infections may induce PBC. The pathogenetic mechanism is believed to be caused by a defect in immunologic tolerance, resulting in the activation and expansion of self-antigen specific T and B lymphocyte clones and the production of circulating autoantibodies in addition to a myriad of cytokines and other inflammatory mediators. This leads to ductulopenia and persistent cholestasis, by developing end-stage hepatic-cell failure. In this review are given our own and literary data about mechanisms of development of intrahepatic cholestasis and possible ways of its correction.

[Seropositivity for Chlamydia pneumoniae in patients with primary biliary cirrhosis]

INTRODUCTION

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease characterized by inflammatory injury and bile duct destruction. Recent studies suggest that Chlamydia pneumoniae could be associated with the development of PBC. The aim of this study was to determine the seroprevalence of C. pneumoniae in a cohort of patients with PBC.

PATIENTS AND METHODS

The presence of IgG antibodies against C. pneumoniae was investigated in 46 patients with PBC and in 105 subjects without cirrhosis.

RESULTS

Twenty-one patients (46%) with PBC had antibodies against C. pneumoniae compared with 74 subjects (71%) in the control group (OR = 0.6; 95% CI, 0.3-1.2; p = NS). Subanalysis of the PBC group showed that patients with C. pneumoniae antibodies had a higher frequency of advanced Child-Pugh stages (24% A, 52% B and 24% C vs 64% A, 32% B and 4% C; p = 0.01), a higher score on the Mayo Clinic Prognostic Index (7.8 +/- 2.1 vs 5.6 +/- 1.2; p = 0.004), a higher frequency of ascites (29% vs 4%; OR = 9.6; 95% CI, 1-87; p = 0.02), higher total bilirubin levels (4.5 +/- 2.5 mg/dl vs 2.4 +/- 4.3 mg/dl, p = 0.001) and lower serum albumin levels (2.6 +/- 0.9 g/dl vs 3.3 +/- 0.6 g/dl, p = 0.02).

CONCLUSION

No association was found between C. pneumoniae infection and PBC in this study. An association was found between the severity of PBC and C. pneumoniae, which may suggest a deleterious effect of C. pneumoniae infection or a predisposition in advanced stages of PBC to acquire infection with this microorganism.

Serum leptin, soluble leptin receptor, free leptin index and bone mineral density in patients with primary biliary cirrhosis

BACKGROUND/AIM

The pathophysiology of osteoporosis in chronic liver diseases is unknown. Recent data suggest that serum leptin is associated with bone mineral density (BMD). In animal studies leptin was found to be a potent inhibitor of bone formation. We investigated the relationship between serum leptin levels, soluble leptin receptor (sOB-R), free leptin index (FLI) and BMD in patients with primary biliary cirrhosis (PBC).

PATIENTS AND METHODS

Ninety-four female patients with PBC were included in this study; 122 healthy women served as controls. Serum leptin levels were measured by radioimmunoassay, sOB-R by enzyme-linked immunosorbent assay. BMD was measured by dual energy X-ray absorptiometry in the lumbar spine and femoral neck.

RESULTS

Serum leptin was significantly lower in patients with PBC compared with healthy controls. No difference was found between the body mass index (BMI) of patients and controls. There was a strong positive correlation between leptin and BMI. In PBC no association was found between leptin, sOB-R and liver function tests, histological stages or the presence of osteoporosis. Osteoporosis was present in 38 patients. A positive correlation was found between serum leptin and femoral neck z-score even after adjustment for BMI, whereas serum sOB-R correlated inversely with the serum leptin level. There was no difference in FLI between the subgroups of PBC patients according to the stages of the disease.

CONCLUSIONS

We found a lower serum leptin level and a higher sOB-R in patients with PBC, which could not be explained by the difference in BMI. As leptin was associated with BMD, it may be hypothesized that leptin is involved in the complex regulation of bone metabolism in PBC.