Platelet-leucocyte aggregation is augmented in cirrhosis and further increased by platelet transfusion.

BACKGROUND: Thrombocytopenia and circulating dysfunctional immune cells are commonly observed in patients with cirrhosis. Platelets may form complexes with neutrophils, monocytes and T cells modulating their function. We recently reported increased frequencies of platelet-complexed neutrophils in cirrhosis with evidence of neutrophil activation upon contact with healthy platelets in vitro. Whether this occurs in vivo following platelet transfusion and contributes to systemic inflammation and endothelial activation is unknown. AIMS: To characterise platelet-leucocyte aggregation in cirrhosis and to determine whether elective platelet transfusion results in perturbations associated with changes in markers of haemostasis, inflammation or endothelial activation. METHODS: We collected blood from cirrhotics (n = 19) before and following elective platelet transfusion. We measured platelet-leucocyte aggregation, activation and function, and markers of platelet activation, systemic inflammation and endothelial activation by flow cytometry. Haemostasis was assessed by thromboelastometry and plasma haemostatic proteins. RESULTS: We observed a 2.5-fold increase in platelet-complexed neutrophils in patients with cirrhosis compared with healthy subjects and twofold more platelets attached per monocyte and T cell. All platelet-complexed leucocytes expressed higher levels of activation markers and platelet-complexed neutrophils had higher resting oxidative burst and phagocytic capacity than their nonplatelet-complexed counterparts (P < 0.001); most pronounced in patients with cirrhosis. Paradoxically, platelet-complexed leucocyte frequency decreased with increasing MELD score. Platelet transfusion increased soluble CD40 ligand (platelet activation marker), the frequency of platelet-complexed monocytes (P < 0.05) and improved haemostatic status. CONCLUSION: Cirrhotic patients have activated circulating platelet-complexed leucocytes with increased platelet-monocyte aggregation following elective platelet transfusion. Elective platelet transfusion might therefore exacerbate immune dysfunction in cirrhosis.

Review article: the gut microbiome as a therapeutic target in the pathogenesis and treatment of chronic liver disease.

BACKGROUND: Mortality from chronic liver disease is rising exponentially. The liver is intimately linked to the gut via the portal vein, and exposure to gut microbiota and their metabolites translocating across the gut lumen may impact upon both the healthy and diseased liver. Modulation of gut microbiota could prove to be a potential therapeutic target. AIM: To characterise the changes in the gut microbiome that occur in chronic liver disease and to assess the impact of manipulation of the microbiome on the liver. METHODS: We conducted a PubMed search using search terms including 'microbiome', 'liver' and 'cirrhosis' as well as 'non-alcoholic fatty liver disease', 'steatohepatitis', 'alcohol' and 'primary sclerosing cholangitis'. Relevant articles were also selected from references of articles and review of the ClinicalTrials.gov website. RESULTS: Reduced bacterial diversity, alcohol sensitivity and the development of gut dysbiosis are seen in several chronic liver diseases, including non-alcoholic fatty liver disease, alcohol-related liver disease and primary sclerosing cholangitis. Perturbations in gut commensals could lead to deficient priming of the immune system predisposing the development of immune-mediated diseases. Furthermore, transfer of stool from an animal with the metabolic syndrome may induce steatosis in a healthy counterpart. Patients with cirrhosis develop dysbiosis, small bowel bacterial overgrowth and increased gut wall permeability, allowing bacterial translocation and uptake of endotoxin inducing hepatic and systemic inflammation. CONCLUSIONS: Manipulation of the gut microbiota with diet, probiotics or faecal microbiota transplantation to promote the growth of "healthy" bacteria may ameliorate the dysbiosis and alter prognosis.

The severity of circulating neutrophil dysfunction in patients with cirrhosis is associated with 90-day and 1-year mortality.

BACKGROUND: Patients with cirrhosis are susceptible to sepsis, pre-disposing to the development of encephalopathy, bleeding and organ dysfunction with associated high mortality. AIM: To characterise circulating neutrophil function in a cirrhotic cohort as a determinant of 90-day and 1-year mortality. METHODS: Sixty-two patients with cirrhosis [49 stable (Child-Pugh A/B/C = 24%/39%/37%); 13 acute-on-chronic liver failure] were prospectively studied and compared with 11 healthy controls. Neutrophil function was evaluated at baseline and repeated at critical points during the course of the patient's illness until death/transplantation. Neutrophil phenotype was determined using fluorochrome-labelled antibodies to CD16/CD11b and assessed by flow cytometry. Neutrophil phagocytic activity (NPA) and capacity (NPC) were determined using FITC-labelled opsonised Escherichia coli. Oxidative burst (OB) was quantified by the percentage of neutrophils producing reactive oxygen species (ROS) and mean fluorescence intensity at rest, and after stimulation with E. coli. Physiological variables, biochemistry, microbiology and outcomes were collected. Plasma pro- and anti-inflammatory cytokine profiles were performed by ELISA. RESULTS: NPA/NPC was impaired in cirrhosis with the most significant dysfunction being observed in those with advanced disease and in those treated with propranolol. NPC predicted survival in stable cirrhosis [AUROC 0.83 (95% CI 0.68-0.97); P = 0.021] and differentiated survivors from nonsurvivors (90-day P = 0.01; 1 year P < 0.001). Resting OB ≥12% predicted 90-day mortality with 80% sensitivity and 71% specificity [AUROC 0.81 (95% CI 0.64-0.97); P = 0.026 and differentiated survivors from nonsurvivors; P = 0.015]. CONCLUSION: Circulating neutrophils in patients with cirrhosis are dysfunctional and predict the development of infection, organ dysfunction and survival at 90 days and 1 year.

Comparison of scoring systems and outcome of patients admitted to a liver intensive care unit of a tertiary referral centre with severe variceal bleeding.

BACKGROUND: Acute variceal haemorrhage (AVH) is associated with significant mortality. AIMS: To determine outcome and factors associated with hospital mortality (HM) in patients with AVH admitted to intensive care unit (ICU) and to compare outcomes of patients requiring transfer to a tertiary ICU (transfer group, TG) to a local in-patient group (LG). METHODS: A retrospective study of all adult patients (N = 177) admitted to ICU with AVH from 2000-2008 was performed. RESULTS: Median age was 48 years (16-80). Male represented 58%. Median MELD score was 16 (6-39), SOFA score was 8 (6-11). HM was higher in patients who had severe liver disease or critical illness measured by MELD, SOFA, APACHE II scores and number of failed organs (NFO), P < 0.05. Patients with day-1 lactate ≥ 2 mmol/L had increased HM (P < 0.001). MELD score performed as well as APACHE II, SOFA and NFO (P < 0.001) in predicting HM (AUROC = 0.84, 0.81, 0.79 and 0.82, respectively P > 0.05 for pair wise comparisons). Re-bleeding was associated with increased HM (56.9% vs. 31.6%, P = 0.002). The TG (n = 124) had less severe liver disease and critical illness and consequently had lower HM than local patients (32% vs. 57%, P = 0.002). TG patients with ≥2 endoscopies prior to transfer had increased 6-week mortality (P = 0.03). Time from bleeding to transfer ≥3 days was associated with re-bleeding (OR = 2.290, P = 0.043). CONCLUSIONS: MELD score was comparable to ICU prognostic models in predicting mortality. Blood lactate was also predictive of hospital mortality. Delays in referrals and repeated endoscopy were associated with increased re-bleeding and mortality in this group.

Review article: the design of clinical trials in hepatic encephalopathy--an International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) consensus statement.

BACKGROUND: The clinical classification of hepatic encephalopathy is largely subjective, which has led to difficulties in designing trials in this field. AIMS: To review the current classification of hepatic encephalopathy and to develop consensus guidelines on the design and conduct of future clinical trials. METHODS: A round table was convened at the 14th International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) meeting. Key discussion points were the nomenclature of hepatic encephalopathy and the selection of patients, standards of care and end-points for assessing the treatment and secondary prevention of hepatic encephalopathy. RESULTS: It was generally agreed that severity assessment of hepatic encephalopathy in patients with cirrhosis, whether made clinically or more objectively, should be continuous rather than categorical, and a system for assessing the SONIC (Spectrum of Neuro-cognitive Impairment in Cirrhosis) was proposed. Within this system, patients currently classified as having minimal hepatic encephalopathy and Grade I hepatic encephalopathy would be classified as having Covert hepatic encephalopathy, whereas those with apparent clinical abnormalities would continue to be classified as overt hepatic encephalopathy. Some aspects of the terminology require further debate. Consensus was also reached on the patient populations, standards of care and endpoints to assess clinical trial outcomes. However, some compromises had to be made as there is considerable inter- and intravariability in the availability of some of the more objective surrogate performance markers. CONCLUSIONS: The objectives of the round table were met. Robust, defendable guidelines for the conduct of future studies into hepatic encephalopathy have been provided. Outstanding issues are few and will continue to be discussed.

Infection and systemic inflammation, not ammonia, are associated with Grade 3/4 hepatic encephalopathy, but not mortality in cirrhosis.

BACKGROUND & AIMS: Patients with cirrhosis are prone to infection which is a frequent precipitant of hepatic encephalopathy (HE). Clinical studies have examined the importance of inflammation and infection in modulating the manifestation of symptoms of HE in acute liver failure and patients with cirrhosis and minimal/low grade HE. It would be logical to presume that this relationship persists in patients who develop severe HE in cirrhosis although this has not been examined to date. METHODS: We report the findings of a prospective audit of 100 consecutive patients with cirrhosis admitted between Jan 2000 and March 2008 to a liver Intensive Care Unit (ICU) where HE was the primary indication for admission (59% Grade 3; 41% Grade 4). Haematological and microbiological data were collected at ICU admission, and organ scores and outcomes were recorded. RESULTS: 46% of patients had positive cultures taken within ± 48h from admission to ICU [25% blood] and a further 22% were culture negative but had evidence of systemic inflammation (SIRS). SIRS score (p=0.03) and SOFA score (p=0.006) were significantly higher in those patients with Grade 4 HE, who were also less likely to survive (p<0.001). HE grade/coma score did not correlate with ammonia, biochemistry or MELD score. Fifty-two percent of patients survived their ICU stay while the remainder developed progressive multiorgan failure and died; 38% survived to discharge, and 16% were transplanted. CONCLUSIONS: These data support an association between infection/SIRS and not ammonia, in patients with cirrhosis that develop severe HE. The presence or absence of infection/SIRS did not determine survival.

Role of ammonia and inflammation in minimal hepatic encephalopathy.

BACKGROUND: Minimal hepatic encephalopathy (MHE) is common in cirrhosis but its pathophysiologic basis remains undefined. We evaluated whether the presence of MHE was associated with severity of liver disease, ammonia levels or the presence of inflammation and assessed factors determining neuropsychological deterioration accompanying induction of hyperammonemia. METHODS: Eighty four cirrhotics were studied. A neuropsychological test battery was performed and blood taken for ammonia, WCC, CRP, nitrate/nitrite, IL-6 and amino acids, before and after, induction of hyperammonemia by administration of a solution mimicking the amino acid composition of haemoglobin (60) or placebo (24). RESULTS: The presence and severity of MHE were independent of severity of liver disease and ammonia concentration but markers of inflammation were significantly higher in those with MHE compared with those without. Induction of hyperammonemia produced deterioration in one or more neuropsychological tests by > or =1 SD in 73.3%. This was independent of the magnitude of change in plasma ammonia and severity of liver disease but was significantly greater in those with more marked inflammation. CONCLUSION: Our data show that inflammation is an important determinant of the presence and severity of MHE. The change in neuropsychological function following induced hyperammonemia is greater in those with more severe inflammation.

The pathophysiologic basis of hepatic encephalopathy: central role for ammonia and inflammation.

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome associated with both acute and chronic liver dysfunction. It defines prognosis in acute liver injury in which patients can succumb with brain oedema and intracranial hypertension. In cirrhosis, it occurs insidiously, causing a range of neuropsychiatric disturbances. For over a century, we have known that ammonia is important in its pathogenesis and astrocytes are the cells that have been most commonly found to be affected neuropathologically. In this review we centre on the story of the 'sick astrocyte', focusing on the molecular pathogenesis of HE and the important role that inflammation has on its modulation. We describe new developments in this area with respect to potential targets for future therapies.

Ammonia and hepatic encephalopathy: the more things change, the more they remain the same.

Ammonia is thought to be central in the pathogenesis of hepatic encephalopathy and has been of importance to generations dating back to the early Egyptians. Hippocrates 2500 years ago described 'encephalopathy' simply translated as 'inside head suffering.' Over 1500 papers have been written on hepatic encephalopathy since 1966, but only a minority of these actually refer to the original observation of hepatic encephalopathy and the link with ammonia made by Marcel Nencki and Ivan Pavlov in 1893 with very little acknowledgement being made to the early landmark studies which described the importance of the muscle and kidneys in maintaining ammonia homeostasis as well as the liver and gut. Furthermore, infection was recognized as being an important modulator of brain function by the ancient Greek physicians and philosophers. This review focuses upon the original experiments of Nencki and Pavlov and describes how they fit into what we understand about the pathophysiology and treatment of hepatic encephalopathy today.

Low myo-inositol and high glutamine levels in brain are associated with neuropsychological deterioration after induced hyperammonemia.

The neuropsychological effect of hyperammonemia is variable. This study tests the hypothesis that the effect of ammonia on the neuropsychological function in patients with cirrhosis is determined by the ability of the brain to buffer ammonia-induced increase in glutamine within the astrocyte by losing osmolytes like myo-inositol (mI) and not by the magnitude of the induced hyperammonemia. Fourteen cirrhotic patients with no evidence of overt hepatic encephalopathy were given a 75-g amino acid (aa) solution mimicking the hemoglobin molecule to induce hyperammonemia. Measurement of a battery of neuropsychological function tests including immediate memory, ammonia, aa, and short-echo time proton magnetic resonance spectroscopy were performed before and 4 h after administration of the aa solution. Eight patients showed deterioration in the Immediate Memory Test at 4 h. Demographic factors, severity of liver disease, change in plasma ammonia, and aa profiles after the aa solution were similar in those that showed a deterioration compared with those who did not. In patients who showed deterioration in the memory test, the mI-to-creatine ratio (mI/Cr) was significantly lower at baseline than those that did not deteriorate. In contrast, the glutamate/glutamine-to-Cr ratio was significantly greater in the patients that deteriorated. The observation that deterioration in the memory test scores was greater in those with lower mI/Cr supports the hypothesis that the neuropsychological effects of induced hyperammonemia is determined by the capacity of the brain to handle ammonia-induced increase in glutamine.