Elevated serum levels of glial fibrillary acidic protein are associated with covert hepatic encephalopathy in patients with cirrhosis

Background & Aims

Blood biomarkers facilitating the diagnosis of covert hepatic encephalopathy (CHE) in patients with cirrhosis are lacking. Astrocyte swelling is a major component of hepatic encephalopathy. Thus, we hypothesised that glial fibrillary acidic protein (GFAP), the major intermediate filament of astrocytes, might facilitate early diagnosis and management. This study aimed to investigate the utility of serum GFAP (sGFAP) levels as a biomarker of CHE.

Methods

In this bicentric study, 135 patients with cirrhosis, 21 patients with ongoing harmful alcohol use and cirrhosis, and 15 healthy controls were recruited. CHE was diagnosed using psychometric hepatic encephalopathy score. sGFAP levels were measured using a highly sensitive single-molecule array (SiMoA) immunoassay.

Results

In total, 50 (37%) people presented with CHE at study inclusion. Participants with CHE displayed significantly higher sGFAP levels than those without CHE (median sGFAP, 163 pg/ml [IQR 136; 268] vs. 106 pg/ml [IQR 75; 153]; p <0.001) or healthy controls (p <0.001). sGFAP correlated with results in psychometric hepatic encephalopathy score (Spearman's ρ = -0.326, p <0.001), model for end-stage liver disease score (Spearman's ρ = 0.253, p = 0.003), ammonia (Spearman's ρ = 0.453, p = 0.002), and IL-6 serum levels (Spearman's ρ = 0.323, p = 0.006). Additionally, sGFAP levels were independently associated with the presence of CHE in multivariable logistic regression analysis (odds ratio 1.009; 95% CI 1.004-1.015; p <0.001). sGFAP levels did not differ between patients with alcohol-related cirrhosis vs. patients with non-alcohol-related cirrhosis or between patients with ongoing alcohol use vs. patients with discontinued alcohol use.Conclusions: sGFAP levels are associated with CHE in patients with cirrhosis. These results suggest that astrocyte injury may already occur in patients with cirrhosis and subclinical cognitive deficits and that sGFAP could be explored as a novel biomarker.

Impact and implications

Blood biomarkers facilitating the diagnosis of covert hepatic encephalopathy (CHE) in patients with cirrhosis are lacking. In this study, we were able to demonstrate that sGFAP levels are associated with CHE in patients with cirrhosis. These results suggest that astrocyte injury may already occur in patients with cirrhosis and subclinical cognitive deficits and that sGFAP could be explored as a novel biomarker.

Prevalence of Minimal Hepatic Encephalopathy in Patients With Liver Cirrhosis: A Cross-Sectional, Clinicoepidemiological, Multicenter, Nationwide Study in India: The PREDICT Study

BACKGROUND

The study aimed at assessing the prevalence and clinical profile of minimal hepatic encephalopathy (MHE) in patients with cirrhosis using neuropsychological assessment and at understanding the management practices of MHE in the Indian clinical setting.

METHODS

This cross-sectional, clinicoepidemiological study conducted at 20 sites enrolled liver cirrhosis patients with Grade 0 hepatic encephalopathy according to West-Haven Criteria. Patients were subjected to mini-mental state examination and those with a score of ≥24 were assessed using psychometric hepatic encephalopathy score. Short Form-36 questionnaire was administered to assess the impact on health-related quality of life.

RESULTS

Of the 1260 enrolled patients, 1114 were included in the analysis. The mean age was 49.5 years and majority were males (901 [81%]). The prevalence of MHE was found to be 59.7% (665/1114) based on the psychometric hepatic encephalopathy score of ≤-5. Alcohol-related liver disease was the most common etiology (482 [43.27%]) followed by viral infection (239 [21.45%]). Past smokers as well as those currently smoking were more likely to have MHE than nonsmokers. A significant association was found between tobacco chewing, smoking, alcohol consumption, diabetes, and the presence of MHE. Multivariable analysis revealed smoking as the only parameter associated with MHE. A total of 300 (26.9%) patients were on prophylaxis with lactulose/lactitol or rifaximin. These patients were less likely to have MHE as compared to those not on prophylaxis (odds ratio, 0.67; 95% confidence interval, 0.50-0.88; P = 0.005).

CONCLUSION

The disease burden of MHE is quite substantial in patients with cirrhosis with no apparent cognitive defect. Smoking, whether past or current, has significant association with the presence of MHE. Although MHE has been shown to adversely affect quality of life, prophylaxis for MHE is not routinely practiced in the Indian setting.The study has been registered under clinical trials registry of India (CTRI/2014/01/004306).

Prevalence of and Factors Associated With Minimal Hepatic Encephalopathy in Patients With Cirrhosis of Liver

BACKGROUND/OBJECTIVES

Minimal hepatic encephalopathy (MHE), though highly prevalent, is a frequently underdiagnosed complication of cirrhosis of the liver. Because lack of time is reported as the major reason for non-testing, identifying patients at high risk of MHE would help in targeting them for screening. We aimed to determine the factors associated with MHE to help identify patient subgroups with a higher risk of MHE for targeted screening.

METHODS

Patients with cirrhosis of liver presenting between April 2015 and November 2016 were included. Those with a Psychometric Hepatic Encephalopathy Score (PHES) of ≤-5 points on psychometric testing were diagnosed to have MHE. Various demographic, clinical and laboratory parameters were included in a univariate and later multiple logistic regression models.

RESULTS

Of the 180 (male = 166, 92.2%) patients included 94 (52.2%) had MHE. Though serum albumin, serum total bilirubin, serum aspartate aminotransferase, international normalized ration, Child-Turcotte-Pugh and Model-For-End-Stage-Liver-Disease scores were significant on univariate analysis, only CTP score was found to be significantly associated with MHE (P = 0.002) on multivariate analysis. A higher CTP class was associated with a higher risk of the presence of MHE. The Odds ratio for having MHE was higher with CTP classes of B (P ≤ 0.001) and C (P ≤ 0.001) compared to class A.

CONCLUSIONS

MHE is a common complication in patients with cirrhosis of liver and higher CTP scores independently predict the presence of MHE. Patients with CTP class B and C have a higher risk of suffering from MHE than CTP class A. Screening of patients in CTP class B and C is likely to increase the MHE detection rates while saving time, although select CTP class A patients may also need screening in view of public safety or poor quality of life.

Management of overt hepatic encephalopathy

Hepatic encephalopathy (HE) is an important complication of cirrhosis with significant morbidity and mortality. Management of HE primarily involves avoidance of precipitating factors and administration of various ammonia-lowering therapies such as non-absorbable disaccharides, antimicrobial agents like rifaximin and l-ornithine l-aspartate. The non-absorbable disaccharides which include lactulose and lactitol are considered the first-line therapy for the treatment of HE and in primary and secondary prophylaxis of HE. Lactitol is comparable to lactulose in the treatment of HE with fewer side effects. Rifaximin is effective in treatment of HE and recent systemic reviews found it comparable to disaccharides and is effective in secondary prophylaxis of HE. Many agents like l-ornithine l-aspartate, probiotics, zinc, sodium benzoate have been tried either alone or in combination with lactulose for the treatment of HE. Combination therapy of disaccharides either with rifaximin, l-ornithine l-aspartate, probiotics for the treatment of HE needs further validation in large studies.

Pathogenesis of hepatic encephalopathy: role of ammonia and systemic inflammation

The syndrome we refer to as Hepatic Encephalopathy (HE) was first characterized by a team of Nobel Prize winning physiologists led by Pavlov and Nencki at the Imperial Institute of Experimental Medicine in Russia in the 1890's. This focused upon the key observation that performing a portocaval shunt, which bypassed nitrogen-rich blood away from the liver, induced elevated blood and brain ammonia concentrations in association with profound neurobehavioral changes. There exists however a spectrum of metabolic encephalopathies attributable to a variety (or even absence) of liver hepatocellular dysfunctions and it is this spectrum rather than a single disease entity that has come to be defined as HE. Differences in the underlying pathophysiology, treatment responses and outcomes can therefore be highly variable between acute and chronic HE. The term also fails to articulate quite how systemic the syndrome of HE can be and how it can be influenced by the gastrointestinal, renal, nervous, or immune systems without any change in background liver function. The pathogenesis of HE therefore encapsulates a complex network of interdependent organ systems which as yet remain poorly characterized. There is nonetheless a growing recognition that there is a complex but influential synergistic relationship between ammonia, inflammation (sterile and non-sterile) and oxidative stress in the pathogenesis HE which develops in an environment of functional immunoparesis in patients with liver dysfunction. Therapeutic strategies are thus moving further away from the traditional specialty of hepatology and more towards novel immune and inflammatory targets which will be discussed in this review.

Encephalopathy in Wilson disease: copper toxicity or liver failure?

Hepatic encephalopathy (HE) is a complex syndrome of neurological and psychiatric signs and symptoms that is caused by portosystemic venous shunting with or without liver disease irrespective of its etiology. The most common presentation of Wilson disease (WD) is liver disease and is frequently associated with a wide spectrum of neurological and psychiatric symptoms. The genetic defect in WD leads to copper accumulation in the liver and later in other organs including the brain. In a patient presenting with Wilsonian cirrhosis neuropsychiatric symptoms may be caused either by the metabolic consequences of liver failure or by copper toxicity. Thus, in clinical practice a precise diagnosis is a great challenge. Contrary to HE in neurological WD consciousness, is very rarely disturbed and pyramidal signs, myoclonus dominate. Asterixis and many other clinical symptoms may be present in both disease conditions and are quite similar. However details of neurological assessment as well as additional examinations could help in differential diagnosis.

Gut microbiota: its role in hepatic encephalopathy

Ammonia, a key factor in the pathogenesis of hepatic encephalopathy (HE), is predominantly derived from urea breakdown by urease producing large intestinal bacteria and from small intestine and kidneys, where the enzyme glutaminases releases ammonia from circulating glutamine. Non-culture techniques like pyrosequencing of bacterial 16S ribosomal ribonucleic acid are used to characterize fecal microbiota. Fecal microbiota in patients with cirrhosis have been shown to alter with increasing Child-Turcotte-Pugh (CTP) and Model for End stage Liver Disease (MELD) scores, and with development of covert or overt HE. Cirrhosis dysbiosis ratio (CDR), the ratio of autochthonous/good bacteria (e.g. Lachnospiraceae, Ruminococcaceae and Clostridiales) to non-autochthonous/pathogenic bacteria (e.g. Enterobacteriaceae and Streptococcaceae), is significantly higher in controls and patients with compensated cirrhosis than patients with decompensated cirrhosis. Although their stool microbiota do not differ, sigmoid colonic mucosal microbiota in liver cirrhosis patients with and without HE, are different. Linkage of pathogenic colonic mucosal bacteria with poor cognition and inflammation suggests that important processes at the mucosal interface, such as bacterial translocation and immune dysfunction, are involved in the pathogenesis of HE. Fecal microbiome composition does not change significantly when HE is treated with lactulose or when HE recurs after lactulose withdrawal. Despite improving cognition and endotoxemia as well as shifting positive correlation of pathogenic bacteria with metabolites, linked to ammonia, aromatic amino acids and oxidative stress, to a negative correlation, rifaximin changes gut microbiome composition only modestly. These observations suggest that the beneficial effects of lactulose and rifaximin could be associated with a change in microbial metabolic function as well as an improvement in dysbiosis.

Inhibitory control test for the detection of minimal hepatic encephalopathy in patients with cirrhosis of liver

BACKGROUND & AIMS

Minimal hepatic encephalopathy (MHE) has significant impact on future clinical outcomes, such as occurrence of overt HE (OHE) and survival in patients of cirrhosis. In the absence of a 'gold standard', psychometric hepatic encephalopathy score (PHES) is widely used for the diagnosis of MHE. This cross-sectional and prospective study was carried out to determine the usefulness of inhibitory control test (ICT) for the diagnosis of MHE.

METHODS

One hundred and two patients with cirrhosis and without a history of OHE were enrolled in to the study and were subjected to PHES and ICT. MHE was diagnosed when the PHES was ≤ -5. ICT was considered abnormal when the numbers of ICT lures were more than 14.

RESULTS

Forty-one (40.2%) patients had MHE. There were 40 patients with normal PHES and ICT, 32 with abnormal PHES and ICT, 9 with abnormal PHES and normal ICT, and 21 with abnormal ICT and normal PHES score. ICT had 78% sensitivity and 65.6% specificity and an area-under-the-curve value of 0.735 (95% CI = 0.632-0.830) for the diagnosis of MHE. In patients with cirrhosis, ICT did not correlate with severity of liver disease as measured by CTP score (r = 0.044, P = 0.658) and MELD score (r = 0.176, P = 0.077). ICT did not predict survival as well as PHES; while 6 (11.3%) patients died among those who had altered ICT compared to 4 (8.2%) patients who did not have altered ICT (P = 0.74), 8 (19.5%) patients died among those who had altered PHES compared to 2 (3.3%) patients who did not have altered PHES (P = 0.013).

CONCLUSION

ICT is not as useful as PHES in diagnosing MHE in patients with cirrhosis of the liver. It does not correlate with disease severity and predict survival as well as PHES.

Pathogenesis, diagnosis, and treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a neuropsychiatric disorder seen in patients with advanced liver disease or porto-systemic shunts. Based on etiology and severity of HE, the World Congress of Gastroenterology has divided HE into categories and sub-categories. Many user-friendly computer-based neuropsychiatric tests are being validated for diagnosing covert HE. Currently, emphasis is being given to view HE deficits as a continuous spectrum rather than distinct stages. Ammonia is believed to play crucial role in pathogenesis of HE via astrocyte swelling and cerebral edema. However, evidence has been building up which supports the synergistic role of oxidative stress, inflammation and neurosteroids in pathogenesis of HE. At present, treatment of HE aims at decreasing the production and intestinal absorption of ammonia. But as the role of new pathogenetic mechanisms becomes clear, many potential new treatment strategies may become available for clinician.