M. Angelico

Relationships between bile salts hydrophilicity and phospholipid composition in bile of various animal species

Bile salts and phospholipids from bile of chicken, dog, sheep, rat, ox, pig, guinea-pig and man were analyzed by high-performance liquid chromatography. Bile salts showed marked differences in their hydrophilic properties, owing to hydroxyl structure and type of conjugation. Phospholipids were generally similar, containing 90-95% of phosphatidylcholine which was made of molecular species containing palmitic acid in the sn-1 position. The comparative analysis of bile salts and phosphatidylcholines profile demonstrated that bile salts hydrophilicity influences the quantity of phosphatidylcholine in bile but not the quality.

High performance liquid chromatographic analysis of molecular species of phosphatidylcholine - development of quantitative assay and its application to human bile

In this paper we propose a novel, rapid and simple high-performance liquid chromatographic (HPLC) method for the identification and quantitation of individual phosphatidylcholine (PC) molecular species from natural mixtures. To overcome difficulties deriving from the lack of adequate standards and from the variability of the responses to UV spectrophotometric detectors currently used in HPLC analysis, we first fractionated and quantitated the major molecular species of a commercial egg PC by means of a preparative column. The identification of PC molecular species was confirmed by gas-liquid chromatographic analysis of fatty acids. We employed the fractions recovered from preparative HPLC to determine the detector calibration factors of the individual molecular species separated using an analytical, high-speed, reversed-phase HPLC column. The proposed method seems to be adequate for the analysis of PC from many biological sources. Its application to the analysis of human hepatic and gallbladder biliary PC is shown.

Switch to 1.5 grams MMF monotherapy for CNI-related toxicity in liver transplantation is safe and improves renal function, dyslipidemia, and hypertension

Although mycophenolate mofetil (MMF) monotherapy has been successfully used in liver transplant recipients suffering from calcineurin‐inhibitor (CNI)‐related chronic toxicity, still no consensus has been reached on its safety, efficacy and tolerability. We attempted the complete weaning off CNI in 42 individuals presenting chronic renal dysfunction and/or dyslipidemia and/or arterial hypertension and simultaneously introduced 1.5 gm/day MMF. CNI could be completely withdrawn in 41 cases. A total of 32 (75%) patients are currently on ≤1.5 gm/day of MMF. Mean follow‐up from the introduction of MMF is 31.5 months and mean length of follow‐up from the beginning of MMF monotherapy is 27.3 months. Renal function improved in 31/36 (89%) cases. Blood levels of cholesterol and triglycerides decreased in 13 of 17 (76%) and 15 of 17 (89%) patients, respectively. Arterial hypertension improved in 4 of 5 (80%) cases. A total of 8 patients showed a single episode of fluctuation of liver function tests during tapering off CNI. This feature was interpreted as an acute rejection (AR), based on the resolution of the clinical setting after escalation of MMF daily dose to 2 gm. A further patient developed a biopsy‐proven AR insensitive to MMF adjustment, requiring reinstitution of the CNI dose. No deaths or major toxicity requiring MMF discontinuation occurred. In conclusion, low dose MMF monotherapy is safe, effective, and well tolerated. Liver Transpl, 2007.

The Tor Vergata weaning off immunosuppression protocol in stable HCV liver transplant patients: The updated follow up at 78 months

BACKGROUND We report the update of the Tor Vergata immunosuppression (IS) weaning protocol in stable hepatitis C virus (HCV) liver transplant (LT) recipients. METHODS The weaning off IS was attempted in 34 patients who had received a LT 63.5+/-20.1 month earlier, for HCV-related end stage liver disease. Patients were observed over a period of 6.5 years. During this time, yearly protocol liver biopsies were performed. Primary endpoints were determined as the feasibility of weaning off IS and its impact on the long term disease progression. Secondary endpoints were defined as the impact on patient morbidity and quality of life. RESULTS Of the 8 originally tolerant patients, 7 remain alive and in good condition, while 1 died of severe HCV recurrence 10 years post-LT and 6 years after complete removal of IS. Four out of 26 intolerant individuals died of HCV recurrence (2x), lung carcinoma (1x) and acute myocardial infarction (1x), after a mean follow up period from LT of 115 (range 100-124). The 10-year survival from LT was comparable (89% vs. 87.5%). Liver graft pathology showed no significant differences between the two groups in terms of staging, fibrosis progression rate, and grading. Quantitative HCV RNA assay showed a significant non-logarithmic difference between the two groups (p = 0.03). The two groups were comparable in terms of liver function tests and lipid profile, whereas they differed with regards to glycaemia. While all tolerant individuals were euglicemic, 11 intolerant individuals developed new onset diabetes that required specific treatment (p = 0.03). Finally, significantly more intolerant patients are suffering from either cardiovascular (14/22 vs. 0/7, p = 0.01) or infectious diseases (13/22 vs. 0/7, p = 0.01). CONCLUSIONS After a 6.5-year follow up, the complete withdrawal of IS in HCV LT recipient remains safe and beneficial to patients, because it reduces the IS-related morbidity and increases the quality of life. The impact on HCV disease recurrence is less marked than after 3.5 years.

Most Helicobacter pylori-Infected Patients Have Specific Antibodies, and Some Also Have H. pylori Antigens and Genomic Material in Bile: Is It a Risk Factor for Gallstone Formation?

Bile may contain a 130-kDa protein endowed withaminopeptidase activity and the ability to promotecholesterol crystallisation. As > 90% of H. pyloristrains have a similar peptidase activity, and half the isolates express a 110- to 140-kDa antigen, theCagA protein, we investigated a possible associationbetween H. pylori infection and gallstones, and thepresence in bile samples of factors related to H. pylori that could increase cholesterolcrystallization. The prevalence of H. pylori infectionwas 82.1% in 112 patients with gallstones and 80.3% in112 controls (NS). Fifteen bile samples out of 23specimens from infected patients (65.2%) containedanti-CagA antibodies. A ~60-kDa antigen only reactingwith an anti-CagA antibody was found in five bilesamples (21.7%) from 23 infected patients. One bilesample (4.1%) contained ureA and cagA genes of H.pylori. The homology of CagA with the N-terminalsequence of aminopeptidase N was very low. We concludedthat the presence of specific antibody to H. pylori in most bile samples tested and of an H. pyloriputative antigen in a discrete number of cases mayrepresent factors that increase the risk of gallstoneformation.

Fasting and postprandial serum bile acids as a screening test for hepatocellular disease

Postprandial serum bile acid estimation was recently proposed as the most sensitive test of liver function. In our study, the fasting and postprandial serum bile acid measurements were performed on 19 normal subjects, 20 patients with cirrhosis, 10 with acute hepatitis, 4 with resolving viral hepatitis, and 6 with chronic active hepatitis. A gas-chromatographic method was used. One healthy subject had postprandial serum bile acid levels above the normal range, while 7 patients with liver disease had postprandial levels within normal limits. Of the latter group, 2 had chronic active hepatitis in remission and 3 had resolving viral hepatitis. Significant correlations were seen between serum bile acid levels and most of the conventional “liver function” tests. Our data indicate that the postprandial serum bile acid determination is better than any of the other conventional tests taken separately, but no better than their combined use. No significant modification of the cholic acid/chenodeoxycholic acid ratio was observed between the fasting and the postprandial determinations.

Structure of biliary phosphatidylcholine in cholesterol gallstone patients.

The fatty acid composition of biliary phosphatidylcholine was analyzed in 13 patients with radiolucent gallstones undergoing elective cholecystectomy, and in 11 normolipemic patients without gallstones undergoing abdominal surgery. The only difference in the percentage fatty acid composition between the two groups was a significantly (p<0.05) higher percentage arachidonic acid in the first group. This acid was exclusively located in thesn-2 position of phosphatidylcholine (PC), accounting for 13.0±4.9% in the first group and 8.2±4.9% in the second (p<0.05). The percentage arachidonic acid of PC was negatively correlated (p<0.001) with the percentage biliary chenodeoxycholate in gallstone patients, but not in controls. Explanation of these findings is, at present, only speculative.

Effect of a medium dose of ursodeoxycholic acid with or without taurine supplementation on the nutritional status of patients with cystic fibrosis: a randomized, placebo-controlled, crossover trial

Ursodeoxycholic acid administration has been reported to improve cholestasis and inflammatory activity in primary biliary cirrhosis and, in an uncontrolled study, also in young adults with cystic fibrosis (CF) and chronic cholestasis. As an improvement in nutritional status was also observed in these young adult patients, we investigated whether the administration of a medium dose of ursodeoxycholic acid ameliorates the nutritional status of malnourished young adult CF patients with chronic liver disease. The study included 51 patients (27 male patients and 24 female patients; age range, 8–32 years; median, 14) with body mass percentiles < 90%. Patients were randomly assigned to receive either ursodeoxycholic acid (10–12 mg/kg/day) alone or with taurine (18–22 mg/kg/day). Patients were followed in a crossover fashion within each group; 6 months of treatment was randomly alternated with 6 months of placebo. Nine patients dropped out before concluding the study. Liver function tests, nutritional status, and coefficients of fat absorption were determined at entry and after each 6 months of placebo or treatment. Nutritional status and fat absorption were not significantly modified by either treatment. Liver function tests improved after ursodeoxycholic acid administration only in patients with concomitant chronic liver disease. Our findings indicate that 6 months of therapy with a medium dose of ursodeoxycholic acid, either alone or with taurine, does not improve the nutritional status of young malnourished CF patients. Higher doses given for longer periods might be worth investigating.

Octopamine plasma levels and hepatic encephalopathy: a re-appraisal of the problem

An investigation on the blood levels of octopamine was carried out on 70 adult individuals. There was a statistically significant correlation between the levels of octopamine and hepatic encephalopathy. Normal subjects had values below 1 ng/ml, while patients with grade 3 or grade 4 encephalopathy constantly showed values above 3.2 ng/ml. In these two groups the distribution was fairly homogeneous. Through the differences between cirrhotics without neurologic involvement and those with grade 1 or 2 hepatic encephalopathy displayed statistical significance, distribution of values in these groups was rather non-homogeneous. Octopamine levels paralleled variations in mental state in 3 out 4 cases. No difference was found between venous and arterial values. The reaction of transmethylation used in the assay of octopamine was constantly found to be inhibited by the presence of plasma. This inhibition is probably due to the presence of one or more beta-hydroxyphenylethanolamines other than octopamine.

Effect of glucose and/or branched chain amino acid infusion on plasma amino acid imbalance in chronic liver failure.

The characteristic amino acid pattern observed in chronic liver failure with high aromatic and low branched chain amino acid levels is considered to be consequent to increased muscle protein catabolism. The main catabolic stimulus has been attributed to hyperglucagonemia and to a reduced insulin/glucagon molar ratio. Intravenous administration of a solution containing branched chain amino acids and glucose to patients with chronic liver cirrhosis rapidly normalizes the plasma amino acid pattern. This effect may result from either a change in the insulin/glucagon ratio, induced by glucose, or from the anticatabolic influence of branched chain amino acids on muscle protein turnover. To discriminate between these two possibilities, a crossover study was carried out to determine the effect of a 24-hour infusion of either glucose alone, or glucose plus branched chain amino acids, in seven patients with chronic liver failure. Blood glucose, insulin, glucagon, free fatty acids, and amino acid levels were determined. Branched chain amino acids were much more effective than glucose (p less than 0.01) in decreasing the levels of aromatic amino acids. Conversely, the insulin, glucagon, and free fatty acid levels with glucose alone were not altered with the addition of branched chain amino acids. These findings suggest an anticatabolic effect of branched chain amino acids on muscle protein turnover and suggest that factors other than insulin and glucagon may be responsible for the characteristic plasma amino acid pattern present in chronic liver failure.