Urinary metabolic profiling by 1H NMR spectroscopy in patients with cirrhosis may discriminate overt but not covert hepatic encephalopathy.

To date urinary metabolic profiling has been applied to define a specific metabolic fingerprint of hepatocellular carcinoma on a background of cirrhosis. Its utility for the stratification of other complications of cirrhosis, such as hepatic encephalopathy (HE), remains to be established. Urinary proton nuclear magnetic resonance (1H-NMR) spectra were acquired and NMR data from 52 patients with cirrhosis (35 male; 17 female, median (range) age [60 (18-81) years]) and 17 controls were compared. A sub-set of 45 patients (33 male; 12 female, [60 (18-90) years, median model for end stage liver disease (MELD) score 11 (7-27)]) were fully characterised by West-Haven criteria, Psychometric Hepatic Encephalopathy Score (PHES) and electroencephalogram (EEG), and defined as overt HE (OHE, n = 21), covert HE (cHE, n = 7) or no HE (n = 17). Urinary proton nuclear magnetic resonance (1H-NMR) spectra were analysed by partial-least-squares discriminant analysis (PLS-DA). The results showed good discrimination between patients with cirrhosis (n = 52) and healthy controls (n = 17) (R2X = 0.66, R2Y = 0.47, Q2Y = 0.31, sensitivity-60 %, specificity-100 %) as the cirrhosis group had higher 1-methylnicotinamide with lower hippurate, acetate, phenylacetylglycine and N-methyl nicotinic acid levels. While patients with OHE could be discriminated from those with no HE, with higher histidine, citrate and creatinine levels, the best models lack robust validity (R2X = 0.65, R2Y = 0.48, Q2Y = 0.12, sensitivity-100 %, specificity-64 %) with the sample size used. Urinary 1H-NMR metabolic profiling did not discriminate patients with cHE from those without HE, nor discriminate subjects on the basis of PHES/EEG result or MELD score. In conclusion, patients with cirrhosis showed different urinary 1H-NMR metabolic profiles compared to healthy controls and those with OHE may be distinguished from those with no HE although larger studies are required. However, urinary 1H-NMR metabolic profiling did not discriminate patients with differing grades of HE or according to severity of underlying liver disease.

Melatonin secretion and metabolism in patients with hepatic encephalopathy.

BACKGROUND AND AIM: The rhythm of melatonin secretion and its blood level changes in cirrhotic patients, but the causes of these alterations have not been sufficiently appreciated. The aim of study was to estimate the dependence between melatonin secretion and metabolism and the severity of hepatic encephalopathy. METHODS: The study included 75 alcoholic cirrhotic patients (A, B, C) with hepatic insufficiency and 25 healthy subjects (group K). Three groups of patients were identified, 25 patients each, with grade 1, 2, and 3 hepatic encephalopathy according to West-Haven Scale. Immunoenzymatic method was used to measure serum melatonin (at 02:00 h and 09:00 h) level and 6-sulfatoxymelatonin (6-HMS) excretion in the urine (during night and day). RESULTS: Nocturnal serum melatonin levels (pg/mL) in groups were: K-57.1 ± 11.4, A-38.5 ± 11.2, B-53.4 ± 17.9, C-79.5 ± 27.9 (P < 0.01); whereas diurnal levels were: K-10.9 ± 3.5, A-33.5 ± 12.0, B-53.8 ± 23.1, C-98.5 ± 34.6 (P < 0.01). Similar differences were found in the evaluation of 6-HMS excretion (µg/9 h) in urine at night: group K-23.4 ± 14.4, A-16.6 ± 5.4, B-14.3 ± 6.2 (P < 0.01), C-3.3 ± 1.5 (P < 0.001). Diurnal 6-HMS excretion (µg/15 h) was lower only in group C and it was respectively: K-6.9 ± 3.4, A-7.1 ± 1.7, B-7.6 ± 1.7, C-4.3 ± 2.2 (P < 0.001). Serum ammonia concentrations (µg/dL) were: group K-30.4 ± 8.9, A-51.8 ± 25.4 (P < 0.05), B-73.0 ± 29.8 (P < 0.001), C-107.5 ± 34.8 (P < 0.001). No correlation between melatonin and ammonia levels in all groups was found. CONCLUSIONS: The elevated melatonin blood levels both at night and day may account for some of the clinical manifestations of hepatic encephalopathy (daytime sleepiness, fatigue).

Aquaporin-2 urinary excretion in cirrhosis: relationship to vasopressin and nitric oxide.

The aquaporin (AQP) water channel plays an important role in the regulation of water. AQP2 is expressed in the collection duct of the kidney, serving as the final channel that helps to regulate water excretion in the kidneys and affecting the regulation of water and hyponatremia in cirrhotic patients. So far, research on aquaporin expression in cirrhosis has had various results. The purpose of this study is to investigate the factors that affect the regulation of expression of AQP in patients with cirrhosis. The study comprised 81 cirrhosis patients and 18 control subjects. In each group, 24-h urine was collected and nitric oxide and vasopressin levels were measured in the blood. The amount of urinary AQP was measured by Western blot. In this study, the positivity rate and amount of expression of AQP was higher in the cirrhotic group than that of the control group. AQP expression in urine was also compared between the groups with use of diuretics and the groups with no use of diuretics. A 57.4% positivity was observed with the former, whereas a 51.5% was seen in the latter. No significance was found between the groups (P = 0.581). Expression of AQP in compensated cirrhotic patients is significantly higher than decompensated cirrhotic patients and is especially higher in cirrhotic patients with ascites than with no ascites. There is no relationship between the concentration of vasopressin and expression of AQP. Concentration of serum NOx is higher in cirrhotic patients than the control group and there is a positive association between the concentration of serum nitric oxide and AQP in urine. In conclusion, expression of AQP is increased in cirrhotic patients and is significantly higher in patients with ascites. There is a positive association between the expression of AQP and concentration of serum nitric oxide.

Renal elimination of protein S-100beta in pigs with acute encephalopathy.

BACKGROUND: Protein S-100beta is an established biochemical marker for cerebral injury in serum. For the further interpretation and possible use of S-100beta serum measurements in acute hepatic encephalopathy, renal elimination of S-100beta was measured in pigs with elevated S-100beta levels due to hepatic encephalopathy. METHODS: Eighteen female Norwegian Landrace pigs were randomly allocated to either hepatic devascularization (n=13) or sham operation (n=5). Repeated samples from the common carotid artery, right renal vein, and urine were simultaneously drawn for S-100beta analysis, using the Sangtec100 Liamat immunoassay. RESULTS: In hepatic devascularized pigs, arterial serum levels of S-100beta increased from 0.96+/-0.04 microg/L (mean +/- SEM) at t = 0h to 1.74+/-0.11 microg/L (mean +/- SEM) at t = 5 h. Urinary excretion increased simultaneously from 8.48+/-3.66 ng/h (mean +/- SEM) to 20.4+/-9.54 ng/h (mean +/- SEM), while renal arterial-venous fluxes for both kidneys increased from 1022+/-404 ng/h (mean +/- SEM) to 2444+/-590 ng/h (mean +/- SEM). CONCLUSIONS: Increased arterial S-100beta levels in pigs with acute hepatic encephalopathy are not a result of decreased renal elimination. The large difference between the renal arterial venous S-100beta concentrations and the urinary excretion of S-100beta indicate that renal metabolism is the major route of elimination.

Effects of a branched-chain amino acid-enriched diet on chronic hepatic encephalopathy in dogs.

A decreased ratio of branched-chain amino acids (BCAA) to aromatic amino acids (AAA) is considered an important pathogenetic factor in hepatic encephalopathy (HE). A relationship between the deranged BCAA/AAA ratio and dopaminergic dysfunction through the formation of "false" neurotransmitters has been postulated. The intermediate lobe of the pituitary is more pronounced in dogs than in humans and because it is primarily under dopaminergic inhibitory influence, it may serve as an indicator of alterations in dopaminergic neurotransmission. We investigated the effects of a diet with a high BCAA/AAA ratio (HR) and an isonitrogenous diet with a low BCAA/AAA ratio (LR) on several physical and biochemical parameters including pituitary function in dogs with portocaval shunts and 40% hepatectomy and in sham-operated pair-fed controls, in a double-blind, randomized cross-over study. Portocaval-shunted dogs had hyperammonemia (33+/-3 microM (mean +/- SEM) before and 214+/-21 after surgery)) and signs of HE. Their BCAA/AAA ratio in plasma and CSF decreased from 4.3+/-0.3 and 2.3+/-0.3 before surgery to 1.3+/-0.1 and 0.5+/-0.1 after surgery, respectively. These parameters remained unaltered in the control dogs. The consumption of the LR diet was significantly higher than consumption of the HR diet. In the portocaval-shunted dogs, plasma ammonia concentration was higher on the HR diet than on the LR diet (344+/-52 v 246+/-45) and the HE grade was worse. The BCAA/AAA ratio remained abnormal in HE dogs during the feeding of both diets. The basal and haloperidol-stimulated release of alpha-melanotropin and cortisol in plasma were not significantly different between or within groups during any period. In contrast, urinary cortisol excretion was increased in the HE dogs after surgery (urinary cortisol:creatinine ratio (x10(-6)) 8.5+/-1.4 before and 30.4+/-8.9 after surgery). The basal plasma concentration of adrenocorticotropin in HE dogs was decreased after surgery (68.3+/-10.2 ng/L before and 40.8+/-4.4 after surgery). This indicates a non-pituitary-dependent hyperresponsiveness of the adrenals. We conclude from these results that chronic HE in dogs is not associated with an abnormal dopaminergic neurotransmission at least at the level of the pituitary, and that it is not the content of the dietary neutral amino acids but rather the total protein intake that may have a beneficial effect on HE.

Duplicate prealbumin bands in urine. Association with hepatorenal failure.

By electrophoresis, prealbumin is seen as a discrete band anodic to the albumin fraction. Cases of duplicate bands in the prealbumin region have been described previously in serum, cerebrospinal fluid, and urine, and have had an association with varied clinical entities. The authors describe a novel association of severe hepatic and renal failure with the presence of prominent duplicate prealbumin bands in urine.

Atracurium infusions in patients with fulminant hepatic failure awaiting liver transplantation.

OBJECTIVE: To determine the pharmacokinetics and pharmacodynamics of the neuromuscular blocking agent atracurium besylate in patients with fulminant hepatic failure (FHF). DESIGN: Open study of patients receiving atracurium infusions to facilitate mechanical ventilation. SETTING: Intensive care unit in a tertiary referral university teaching hospital. PATIENTS: Ten encephalopathic patients with FHF requiring mechanical ventilation while awaiting orthotopic liver transplantation. Three patients died before transplantation could be performed, three died after transplantation, and four survived following successful transplantation. METHODS: Plasma, urine and dialysate fluid were analysed for atracurium and its metabolites using HPLC. Neuromuscular blockade was measured using transcutaneous ulnar nerve stimulation and an accelerometer. Electroencephalography and liver function tests were performed daily. RESULTS: Patients received atracurium infusions for a period ranging from 38 to 217 h. Six patients required continuous arteriovenous haemodiafiltration (CAVHD) to replace renal function. Atracurium mean steady state clearance was 8.6 ml/min/kg, and train-of-four recovery ratio to 75% took 63 min (range 32-108). Laudanosine clearance was markedly reduced in the non-survivors; the half-life was 38.5 hrs compared with 5.3 h in the 4 patients who underwent successful transplantation. Laudanosine accumulation could be observed in all patients before transplantation, but kinetics returned to normal after successful transplantation. The highest laudanosine level recorded was 6,860 ng/ml. There was no evidence of adverse central neurological effects attributable to laudanosine. CAVHD did not contribute significantly to clearance of atracurium or its metabolites. CONCLUSIONS: Atracurium kinetics and dynamics are near-normal even in patients with fulminant hepatic failure and renal failure; laudanosine accumulation will occur, but this is not associated with measurable central neurological effects. Implantation of a functioning liver graft results in clearance of laudanosine, which seems to be independent of renal function. Atracurium is an appropriate choice for producing neuromuscular blockade for periods of several days in patients with fulminant hepatic failure and renal impairment.

Fractional excretion of beta-2-microglobulin in the urine of patients with normal or reduced renal function and hepatic coma.

The purpose of this prospective study was to evaluate beta-2-microglobulin (beta 2m) as a differential diagnostic indicator between hepatic nephropathy (HN) and acute tubulointerstitial nephropathy (ATIN) in patients with reduced renal function and hepatic coma, and to determine whether beta 2m excretion could be used as a marker of renal impairment before increased serum creatinine (S-Cr) concentration or decreased creatinine clearance (Cr-Cl). Finally, the use of beta 2m as a prognostic indicator was investigated. Eighteen patients in hepatic coma grade III-IV were entered in the study and were divided into two groups in accordance with their renal function (serum creatinine above/below 180 mumol/l). The fractional excretion of beta 2m (FE-beta 2m) was used to monitor beta 2m elimination. The study failed to show any distinction in FE-beta 2m between HN and ATIN patients, presumably owing to the small number of patients. FE-beta 2m could not predict the development of renal failure earlier than the increase in S-Cr or decrease in Cr-Cl. However, a few patients who survived paracetamol intoxication had increased FE-beta 2M in the beginning of the coma and normal S-Cr and Cr-Cl. Patients who died as a result of paracetamol intoxication had both abnormal FE-beta 2m and abnormal S-Cr and Cr-Cl, suggesting that if therapy had been initiated earlier, when only FE-beta 2m was affected, these patients might have survived. All patients who survived, except three paracetamol- and one aminoglycoside-intoxicated patient, had normal FE-beta 2m in the beginning of the coma.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of lactulose and lactitol on protein digestion and metabolism in conventional and germ free animal models: relevance of the results to their use in the treatment of portosystemic encephalopathy.

Protein digestion and metabolism have been studied in laboratory rats and miniature pigs to investigate the mechanisms of action of lactulose and lactitol when used in the treatment of patients with portosystemic encephalopathy. Lactulose (beta-D-galactopyranosyl-(1----4)-beta-D-fructofuranose) and lactitol (beta-D-galactopyranosyl-(1----4)-D-glucitol) increased the excretion of nitrogenous material in the faeces and decreased nitrogen excretion in the urine in a similar degree to that reported for human patients. In studies with germ free rats given lactulose no such effect was observed, suggesting that, for lactulose at least, these effects are mediated by the gut flora. Measurement of the alpha-, epsilon-diaminopimelic acid content of the faeces confirmed that the enhancement of faecal nitrogen was due to an increased contribution from bacteria. The similarity in the results for lactulose and lactitol suggests that, from the perspective of protein metabolism, lactitol acts in a similar way to lactulose in the treatment of portosystemic encephalopathy.

"Endogenous" benzodiazepine activity in body fluids of patients with hepatic encephalopathy.

Body fluids from patients with hepatic encephalopathy and from controls with no renal or hepatic disease were assayed for benzodiazepine immunoreactivity and benzodiazepine-receptor-binding activity. The subjects had taken no synthetic benzodiazepines for at least 3 months. Benzodiazepine receptor binding in cerebrospinal fluid was significantly higher in hepatic encephalopathy patients than in controls (210 [SE 50.2] vs 40.7 [7.3] oxazepam equivalents [ng/ml]). The severity of hepatic encephalopathy was directly and significantly correlated with the level of benzodiazepine activity by radioreceptor assay or radioimmunoassay in urine and in plasma. Benzodiazepine activity equivalent to levels of more than 900 ng/ml was found in patients with advanced encephalopathy. Although the chemical identity and source of this substance (or substances) are still unknown, its properties and the estimated levels of activity suggest it may have a role in the pathogenesis of the neural inhibition seen in hepatic encephalopathy.

Serum and urinary copper in acute hepatic encephalopathy.

Serum and 24 hours' urinary copper levels were studied in 71 patients with acute viral hepatitis including 35 with encephalopathy. Thirty age and sex matched healthy controls were also studied. Copper estimation was done by atomic absorption spectrophotometry. Serum and 24 hours' urinary copper levels (164.85 +/- 29.31 micrograms/dl and 123.54 +/- 7.87 micrograms/24 h respectively) were significantly (P less than 0.001) increased in acute viral hepatitis patients. There was no significant difference in levels between patients with and without encephalopathy.

Hypophosphataemia and phosphaturia in paracetamol poisoning.

To find out whether the hypophosphataemia in paracetamol poisoning is due to renal loss of phosphate, serum phosphate concentrations were correlated with indices of hepatotoxicity in 273 patients who had taken an overdose of paracetamol, and the renal handling of phosphate was examined in another 40 patients. Hypophosphataemia was a feature of paracetamol poisoning, whether hepatotoxicity was present or not. It correlated with the degree of hepatic damage and was not influenced by glucose infusions. Serum phosphate correlated with renal threshold phosphate concentration, so renal loss rather than intracellular redistribution of phosphate seems to be the reason for the hypophosphataemia in paracetamol overdose, and it correlates well with other indices of severity of poisoning.

Zinc abnormalities in fulminant hepatic failure.

Zinc is an important trace metal and, in liver disease, abnormal zinc metabolism has been reported. In this study of patients with fulminant hepatic failure progressing to grade IV encephalopathy, plasma zinc concentrations fell during the illness to reach levels significantly below normal; during this time urinary zinc excretion was markedly elevated.

Urinary excretion of dimethyltryptamine in liver disease.

The urinary excretion of N,N-dimethyltryptamine (DMT) was higher in patients with severe liver disease than in normal subjects. This difference remained significant when patients with all grades of hepatic encephalopathy were excluded. Patients with liver disease whose mental states were normal excreted amounts of DMT similar to those of patients with a hospital diagnosis of schizophrenia.