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

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.

Osteosarcopenia in autoimmune cholestatic liver diseases: Causes, management, and challenges

Primary biliary cholangitis and primary sclerosing cholangitis (PSC) are the most common cholestatic liver diseases (CLD) in adults and are both characterized by an immune pathogenesis. While primary biliary cholangitis is a model autoimmune disease, with over 90% of patients presenting very specific autoantibodies against mitochondrial antigens, PSC is considered an immune mediated disease. Osteoporosis is the most common bone disease in CLD, resulting in frequent fractures and leading to significant morbidity. Further, sarcopenia is emerging as a frequent complication of chronic liver diseases with a significant prognostic impact and severe implications on the quality of life of patients. The mechanisms underlying osteoporosis and sarcopenia in CLD are still largely unknown and the association between these clinical conditions remains to be dissected. Although timely diagnosis, prevention, and management of osteosarcopenia are crucial to limit the consequences, there are no specific guidelines for management of osteoporosis and sarcopenia in patients with CLD. International guidelines recommend screening for bone disease at the time of diagnosis of CLD. However, the optimal monitoring strategies and treatments have not been defined yet and vary among centers. We herein aim to comprehensively outline the pathogenic mechanisms and clinical implications of osteosarcopenia in CLD, and to summarize expert recommendations for appropriate diagnostic and therapeutic approaches.

Leptin Enhances Hepatic Fibrosis and Inflammation in a Mouse Model of Cholestasis

Leptin is an adipokine with roles in food intake and energy metabolism through its actions on neurons in the hypothalamus. The role of leptin in obesity and cardiovascular disorders is well documented. However, its influence on liver conditions such as cholestasis is poorly understood. The effects of exogenous leptin and leptin-neutralizing antibody on biliary hyperplasia, hepatic fibrosis, and inflammation in the multidrug resistance protein 2 knockout (Mdr2KO) mouse model of cholestasis were assessed by quantifying markers specific for cholangiocytes, activated hepatic stellate cells (HSCs), and cytokines. Serum and hepatic leptin were increased in Mdr2KO mice compared with FVB/NJ (FVBN) controls, and exogenous leptin enhanced biliary hyperplasia and liver fibrosis in Mdr2KO and FVBN mice. Leptin administration increased hepatic expression of C-C motif chemokine ligand 2 and IL-6 in Mdr2KO mice. In contrast, leptin-neutralizing antibody reduced intrahepatic bile duct mass and decreased HSC activation in Mdr2KO mice compared with FVBN controls. Sex-related differences were noted, with female Mdr2KO mice having more leptin than males. In cholangiocytes and LX2 cells in vitro, leptin increased phosphorylated Akt and stimulated cell proliferation. Leptin receptor siRNA and inhibitors of Akt phosphorylation impaired leptin-induced cell proliferation and proinflammatory cytokines. The current data suggest that leptin is abnormally increased in cholestatic mice, and excess leptin increases ductular reaction, hepatic fibrosis, and inflammation via leptin receptor-mediated phosphorylation of Akt in cholangiocytes and HSCs.

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.

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.

Expression of fibroblast growth factor 21 in patients with biliary atresia

Fibroblast growth factor 21 is a critical circulating adipokine involving in metabolic disorders and various liver diseases. This study was performed to investigate whether FGF21 is also associated with the pathophysiology of biliary atresia. Serum FGF21 levels were measured in 57 BA patients and 20 age matched healthy controls. We also examined hepatic FGF21 mRNA expression and FGF21 protein levels in liver tissues obtained from 15 BA patients undergoing liver transplantation and 5 cases of pediatric donation after cardiac death donor without liver diseases by RT-PCR and Western blotting. Patients with BA showed significantly higher serum FGF21 levels than those without BA (554.7pg/mL [83-2300] vs. 124.5pg/mL [66-270], P<0.05). Patients with BA also had significantly higher FGF21 mRNA and protein levels in hepatic tissues than control subjects. Serum FGF21 expression increased corresponding to the severity of liver fibrosis. Furthermore, serum FGF21 levels dropped significantly in BA patients within 6months after liver transplantation and approached baseline in healthy controls (P>0.05). In vivo, FXR knockout could significantly abrogate cholestasis induced FGF21 expression. FGF21 levels in serum and liver tissue increased significantly in BA patients. In vivo, cholestasis could induce FGF21 expression in FXR dependent manner.

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.

Association between nutritional screening via the Controlling Nutritional Status index and bone mineral density in chronic liver disease of various etiologies

AIM

Bone density disorders are prevalent in patients with chronic liver disease (CLD), who commonly present with hepatic osteodystrophy. However, the relationship between nutritional status and bone mineral density (BMD) has been scarcely studied in CLD.

METHODS

This single-center, cross-sectional study included outpatients consecutively diagnosed with CLD during a 1.5-year period. The nutritional status was assessed with the Controlling Nutritional Status (CONUT) index; dual-energy X-ray absorptiometry scans and parameters of bone mineral metabolism were carried out. Bone fracture risk was estimated with the World Health Organization FRAX tool.

RESULTS

Among the 126 patients recruited (58.7% male), osteopenia and osteoporosis were present in 31.1% and 10.7%, respectively. The 10-year fracture risk was significantly higher among women. Malnutrition estimated with the CONUT index was present in 29.9% of patients and was significantly more frequent in cirrhotic patients, 63.4% of whom were malnourished. Malnutrition stage directly correlated with hepatic function as expressed by the Model for End-Stage Liver Disease index. A non-significant relationship between CONUT-assessed nutritional status and BMD was documented. 25-Hydroxyvitamin-D3 (25[OH]-D3) and fracture risk correlated positively with the CONUT stage, and total cholesterol had an inverse relationship with BMD.

CONCLUSION

Malnutrition assessed by the CONUT was very frequent in patients with liver cirrhosis. The CONUT score inversely correlated with liver function, while malnutrition stage directly correlated with BMD, fracture risk and 25(OH)-D3. Total cholesterol showed a negative association with BMD in this population.

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.

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.

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.

Changes in bone mineral density in patients with liver cirrhosis

AIM: To observe changes in bone mineral density (BMD) of the femur and lumbar spine in patients with liver cirrhosis and analyze factors potentially correlated with such changes.

METHODS: Sixty liver cirrhosis patients, of which 22 had Child-Pugh A liver function, 18 had Child-Pugh B, and 20 had Child-Pugh C, and 42 healthy volunteers were included in the study. The BMD of the femur and lumbar spine as well as serum calcium (Ca²⁺), inorganic phosphate (P³⁺) and cholinesterase (CHE) were simultaneously measured in both groups. Other parameters such as age, body mass index (BMI) and liver function were also recorded.

RESULTS: The BMD of the femur and lumbar spine was significantly lower in liver cirrhosis patients than in normal controls (P< 0.05 and 0.01, respectively). The BMD of the lumbar spine was significantly lower in patients with Child-Pugh A liver function than in normal controls and patients with Child-Pugh C liver function (0.851 ± 0.207 vs 1.070 ± 022 and 1.036 ± 0.192, respectively; both P < 0.05). A linear correlation was noted between the BMD of the femur and lumbar spine and BMI (r = 2.3 and 2.418, respectively; both P < 0.05) as well as between lumbar BMD and CHE (r = 2.734, P < 0.05).

CONCLUSION: The change in the BMD of the lumbar spine was more significant than that in the BMD of the femur in patients with liver cirrhosis. CHE may predict, to some extent, the change in lumbar BMD.

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.

Alterations of leptin during IFN-alpha therapy in patients with chronic viral hepatitis

BACKGROUND/AIMS

Leptin has a particular profibrogenic role in the liver. We investigated whether IFN-alpha influences leptin production in patients with chronic hepatitis B (CHB) and C (CHC). Leptin was determined in serial samples from 63 CHB and 42 CHC IFN-alpha treated patients. Furthermore, we evaluated whether leptin alterations were associated with patients' characteristics.

METHODS

Sera were investigated at serial time-points using an enzyme-linked-immunosorbent-assay. Controls consisted of 36 patients with autoimmune liver diseases and 44 healthy patients.

RESULTS

Leptin levels before IFN-alpha administration were higher in CHB and CHC compared to healthy (P<0.004) and diseased controls (P=0.0001). In CHB patients, we observed a significant reduction of leptin during IFN-alpha treatment and lasting for up to 6 months after the end of treatment, followed by an increase reaching pretreatment levels at 1.5 years after stopping therapy. The pattern of leptin alterations was similar in CHC patients where leptin's decrease was more pronounced at 6 months after the end of treatment. Biochemical or virological response to treatment was not associated with leptin reduction in both groups.

CONCLUSIONS

This study provides information on leptin kinetics during IFN-alpha treatment and follow-up in CHB and CHC patients and suggests IFN-alpha as a potential inhibitor of leptin production.