Relationship between tumor necrosis factor-alpha and ammonia in patients with hepatic encephalopathy due to chronic liver failure

Hypercytokinemia-induced metabolic encephalopathy in a multiple myeloma patient on hemodialysis undergoing autologous stem cell transplantation: clinical response after plasma exchange

We report here a 50-years old female with multiple myeloma-associated chronic renal failure who underwent high-dose chemotherapy supported by autologous hematopoietic stem cell transplantation. She developed progressive encephalopathy on day 5 progressing to coma despite hemodialysis and no obvious organ failure. She finally recovered after a single 1-liter plasma exchange. The final diagnosis was metabolic encephalopathy due to hypercytokinemia, particularly high serum TNF levels. We discuss here the pathogenesis and raise an alert for monitoring cytokine levels in patients with renal failure undergoing high-dose chemotherapy.

Advance in roles of ammonia and cytokines in hepatic encephalopathy

Hyperammonia theory has been thought as a most feasible mechanism of hepatic encephalopathy following liver injury. Astroglial swelling was reckoned as pathological basis of hepatic encephalopathy. Many assumed mechanisms include oxidative stress activation, mitochondrial permeability transition and glutamine theory, by which ammonia acts on astroglial swelling. Cytokins have influence on the development of hepatic encephalopathy. There are mutual effects of both ammonia and cytokines inducing hepatic encephalopathy.

IL-6 and IL-18 in blood may discriminate cirrhotic patients with and without minimal hepatic encephalopathy

BACKGROUND AND AIMS

Patients with liver cirrhosis may present minimal hepatic encephalopathy (MHE) that can be unveiled using specific neuropsychologic examination. Evaluation of MHE in cirrhotic patients might have prognostic value. The psychometric HE score (PHES) has been recommended as the "gold standard" in the diagnosis of MHE. It has been proposed that critical flicker frequency (CFF) analysis would be useful for easier detection of MHE. It would also be useful to have some peripheral parameter that could reflect the presence of MHE. It has been recently proposed that inflammation-associated alterations and hyperammonemia may cooperate in the induction of hepatic encephalopathy. The aim of the present work was to assess whether there is a correlation between the alterations in parameters reflecting inflammation, hyperammonemia, and the presence of MHE.

METHODS

We have studied in 55 patients with liver cirrhosis and 26 controls the performance in the PHES battery and the CFF, ammonia, and some interleukins (ILs) as inflammatory markers.

RESULTS

IL-6 and IL-18 were significantly higher (2.5-fold and 2.2-fold, respectively) in patients with MHE than in those without MHE. There were significant correlations between IL-6 or IL-18 levels and PHES score and CFF. Moreover, all patients with MHE had IL-6 levels higher than 11 ng/mL, whereas all patients without MHE had IL-6 levels lower than 11 ng/mL.

CONCLUSIONS

Inflammatory alterations related with IL-6 and IL-18 may contribute to MHE. Serum concentration of IL-6 and IL-18 may be useful to discriminate cirrhotic patients with and without MHE.

Decreased heart rate variability in patients with cirrhosis relates to the presence and degree of hepatic encephalopathy

Heart rate variability (HRV) is reduced in several clinical settings associated with either systemic inflammation or neuropsychiatric impairment. The possibility that the changes in HRV observed in patients with neuropsychiatric impairment might relate to the overproduction of inflammatory cytokines does not seem to have been considered in the studies undertaken to date. HRV is decreased in patients with liver cirrhosis but its relationship to the impairment of neuropsychiatric performance, commonly observed in these patients, is unknown. The aim of this study was to investigate the relationship between HRV, hepatic encephalopathy, and production of inflammatory cytokines in patients with cirrhosis. Eighty patients with cirrhosis [53 men, 27 women; mean (+/-1SD) age 54 +/- 10 yr], classified as neuropsychiatrically unimpaired or as having minimal or overt hepatic encephalopathy, and 11 healthy subjects were studied. HRV was assessed by applying Poincaré plot analysis to the R-R interval series on a 5-min ECG. Inflammatory cytokines (TNF-alpha, IL-6, IL-10, and IL-12) were measured in a subgroup of patients. Long-term R-R variability was significantly decreased in the patients with cirrhosis, in parallel with the degree of neuropsychiatric impairment (P < 0.01) and independently of the degree of hepatic dysfunction (P = 0.011). The relative risk of death increased by 7.7% for every 1-ms drop in this variable. Plasma levels of IL-6 significantly correlated with indexes of both HRV and neuropsychiatric performance. The changes observed in HRV and in neuropsychiatric status in patients with cirrhosis are significantly correlated, most likely reflecting a common pathogenic mechanism mediated by inflammatory cytokines.

Tumor necrosis factor-alpha 308.2 polymorphism is associated with advanced hepatic fibrosis and higher risk for hepatocellular carcinoma

BACKGROUND/AIMS

Host genetic factor and hepatic fibrosis may predispose to risk for hepatocellular carcinoma (HCC). This study aimed to assess the association between tumor necrosis factor (TNF) alpha polymorphism and hepatic fibrosis, and risk for HCC.

METHODS

One hundred eight pairs of gender-matched and age-matched patients with HCC and unrelated healthy controls were genotyped for TNF308.2 and TNF238.2 alleles with polymerase chain reaction and direct sequencing.

RESULTS

The frequency of TNF308.1/TNF308.2 genotype in cases was higher than that in controls [odds ratio (OR) = 4.37]. Multivariate analysis indicated that TNF308.2 allele (OR = 3.23), hepatitis B surface antigen (OR = 17.17), and antibodies to hepatitis C virus (OR = 45.52) were independent risk factors for HCC. Surrogate markers for significant fibrosis implied that cases with the TNF308.2 allele have more advanced liver fibrosis. Moreover, multivariate analysis indicated that cirrhosis with Child-Pugh grade C, low serum albumin, and low platelet count were independent risk factors for carrying the TNF308.2 allele.

CONCLUSIONS

TNF308.2 allele carriage and chronic hepatitis B virus/hepatitis C virus infection are independent risk factors for HCC. Carriage of the TNF308.2 allele correlates with disease severity and hepatic fibrosis, which may contribute to a higher risk for HCC.

Pathogenesis of hepatic encephalopathy: the tumour necrosis factor-alpha theory

Hepatic encephalopathy (HE) is a major complication for acute and chronic liver failure. Despite several decades of intensive clinical and basic research, the pathogenesis of HE is still incompletely understood, and the precise mechanisms causing brain dysfunction in liver failure are still not fully established. Several theories concerning the pathogenesis of HE have been previously suggested, including the ammonia theory, which received the most attention. These theories are not mutually exclusive and the validity of none of them has been definitely proved experimentally. In this review article, an attractive theory concerning the pathogenesis of HE, the tumour necrosis factor-alpha (TNF) theory, is presented and comprehensively discussed after accumulation of sufficient data which indicate that the pro-inflammatory cytokine, TNF, is strongly involved in the pathogenesis of HE associated with both acute and chronic liver failure. This theory seems to be superior to all other previous theories in the pathogenesis of HE, and may induce development of other beneficial therapeutical modalities for HE directed towards inhibition of TNF production and/or action, and towards enhancement of its degradation.

Activation of soluble guanylate cyclase by nitric oxide in lymphocytes correlates with minimal hepatic encephalopathy in cirrhotic patients

Patients with liver cirrhosis with normal neurological and mental status examination may present minimal forms of hepatic encephalopathy, showing intellectual function impairment that cannot be detected through general clinical examination but can be unveiled using specific neuropsychological or neurophysiological examination. Evaluation of minimal hepatic encephalopathy (MHE) in cirrhotic patients would have prognostic value. The psychometric hepatic encephalopathy score (PHES) has been recommended as the "gold standard" in the diagnosis of MHE. Altered modulation of cyclic GMP (cGMP) levels in the brain seems to be responsible for the impairment of some types of cognitive function in liver disease. In animal models of liver disease, some of the alterations in modulation of cGMP levels in the brain are reproduced in lymphocytes. The aim of the present work was to assess whether there is a correlation between the alterations in different parameters involved in modulation of cGMP levels and the presence of MHE in patients with liver disease. We studied in 46 patients with liver cirrhosis and 26 controls the performance in the PHES battery of psychometric tests and the critical flicker frequency (CFF), the concentration of cGMP in plasma and lymphocytes, activation of guanylate cyclase by nitric oxide (NO) in lymphocytes, and several parameters likely involved in altered cGMP homeostasis in liver disease such as ammonia, NO metabolites, and atrial natriuretic peptide (ANP). Activation of guanylate cyclase by NO in lymphocytes and cGMP in plasma were higher and CFF lower in patients with MHE than in patients without MHE. Ammonia, ANP, and metabolites of NO were higher in patients than in controls but were no different in patients with or without MHE. Alteration in activation of guanylate cyclase by NO in lymphocytes correlates with PHES performance, CFF, and ammonia levels. This suggests that altered modulation of guanylate cyclase by NO in lymphocytes would reflect a parallel alteration in the brain occurring in patients with MHE that would be involved in their cognitive impairment.

Impaired 11 beta-hydroxysteroid dehydrogenase contributes to renal sodium avidity in cirrhosis: hypothesis or fact?

Exaggerated renal sodium retention with concomitant potassium loss is a hallmark of cirrhosis and contributes to the accumulation of fluid as ascites, pleural effusion, or edema. This apparent mineralocorticoid effect is only partially explained by increased aldosterone concentrations. I present evidence supporting the hypothesis that cortisol confers mineralocorticoid action in cirrhosis. The underlying molecular pathology for this mineralocorticoid receptor (MR) activation by cortisol is a reduced activity of the 11 beta-hydroxysteroid dehydrogenase type 2, an enzyme protecting the MR from promiscuous activation by cortisol in healthy mammalians.