S. Ginanni Corradini

Measurement of oxysterols and α-tocopherol in plasma and tissue samples as indices of oxidant stress status

Oxidant stress seems to play a role in several setting of human pathology, such as atherosclerosis, cancer, and aging. The study of oxidant stress in human disease should be based on the evaluation of either sensitive and specific markers of enhanced oxidant stress, such as oxysterols, or antioxidant defense, by measuring alpha-tocopherol. We have developed a rapid method to measure the oxysterols 7beta-hydroxycholesterol and 7-ketocholesterol in plasma (50 healthy subjects) and tissue as an index of oxidant stress in vivo, and from the same sample alpha-tocopherol content. The mean plasma concentration of 7beta-hydroxycholesterol and 7-ketocholesterol was 4.6+/-1.1 and 13.4+/-7.6 ng/mL, respectively. Plasma alpha-tocopherol concentration was 5.8+/-1.0 micromol/mol cholesterol. Samples from atherosclerotic plaques contained 20 times more cholesterol, about 45 times higher oxysterols levels, and 600 times more alpha-tocopherol compared to normal arteries. No significant difference in cholesterol and oxysterol content was observed between cirrhotic and normal liver. However, cirrhotic liver contained significantly smaller concentration of alpha-tocopherol compared to normal liver. In conclusion, we have developed a rapid and reliable method for the assay of cholesterol oxidation products and alpha-tocopherol in plasma and tissue useful for estimation of oxidant stress/antioxidant balance.

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.

RIFLE Criteria and Hepatic Function in the Assessment of Acute Renal Failure in Liver Transplantation

Renal dysfunction in cirrhotic patients is primary related to disturbances of circulatory function, triggered by portal hypertension with chronic intrarenal vasoconstriction and hypoperfusion. Pretransplant renal function is an important factor implicated in the development of acute renal failure (ARF) after liver transplantation (OLT), but other factors mostly related to liver function seem to influence the development of ARF. The Acute Dialysis Quality Initiative workgroup developed the RIFLE classification to define ARF. We sought to evaluate the incidence of ARF among patients undergoing OLT, to evaluate the association of ARF with pre-OLT renal and hepatic functions, and to evaluate the influence of ARF on chronic kidney disease (CKD) at 1 month post-OLT. Clinical, renal, hepatic function, and donor risk index data of 24 patients who underwent deceased donor OLT were collected before transplantation, in the perioperative period and in the first month post-OLT. ARF occurred in 37.5% of patients with 56% developing the R grade and 44% the I grade; no patient showed the F grade. An association was observed between ARF and a higher Model for End-Stage Liver Disease (MELD) score and between ARF and a reduced pre-OLT serum albumin. No association was noted between ARF and other pre-OLT parameters. In cirrhotic patients serum creatinine is a bias for renal function assessment and the Modification of Diet in Renal Disease formula overestimates GFR. Post-OLT CKD was present in 6.7% of patients without ARF and in 44.4% of patients with ARF. The R grade developed more frequently among patients with viral cirrhosis. The association of ARF with MELD and hypoalbuminemia may be the result of a close relationship between renal and hepatic functions among cirrhotic patients. Post-OLT CKD may be the result of unrecognized, preexisting CKD and/or the effects of not fully resolved acute damage to an injured kidney.

Influence of tauroursodeoxycholic and taurodeoxycholic acids on hepatic metabolism and biliary secretion of phosphatidylcholine in the isolated rat liver

Studies were carried out using an isolated rat liver system to define: the contribution of exogenous phosphatidylcholine (PC) to biliary phospholipid secretion; and its hepatic metabolism during perfusion of the livers with conjugated bile salts with different hydrophilic/hydrophobic properties. A tracer dose of sn-1-palmitoyl-sn-2-[14C]linoleoylPC was injected as a bolus into the recirculating liver perfusate, under constant infusion of 0.75 mumol/min of tauroursodeoxycholate or taurodeoxycholate. The effects on bile flow, biliary lipid secretion, 14C disappearance from the perfusate and its appearance in bile, as well as hepatic and biliary biotransformation were determined. With both the bile salts, about 40% of the [14C]PC was taken up by the liver from the perfusate over 100 min. During the same period less than 2% of the given radioactivity was secreted into bile. More than 95% of the 14C recovered in bile was located within the identical injected PC molecular species. The biliary secretion of labeled as well as unlabeled PC, however, was significantly higher in livers perfused with taurodeoxycholate than tauroursodeoxycholate, while the reverse was observed with respect to bile flow and total bile salt secretion. The exogenous PC underwent extensive hepatic metabolization which appeared to be influenced by the type of bile salt perfusing the liver. After 2 h perfusion, the liver radioactivity was found, in decreasing order, in PC, triacylglycerol, phosphatidylethanolamine and diacylglycerol. In addition, the specific activity of triacylglycerol was significantly higher in tauroursodeoxycholate than in taurodeoxycholate-perfused livers (P less than 0.025), while the reverse was true for the specific activity of hepatic PC (P less than 0.01). Because taurodeoxycholate and tauroursodeoxycholate showed opposite effects on both biliary lipid secretion and hepatic PC biotransformations, we conclude that the hepatic metabolism of glycerolipids is influenced by the physiochemical properties of bile salts.

Model for end-stage liver disease score versus simplified acute physiology score criteria in acute renal failure after liver transplantation

Hepatic function and renal failure are closely related among patients with end-stage liver disease (ESLD) due to splanchnic hemodynamic mechanisms that characterize advanced decompensated cirrhosis. Acute renal failure (ARF) is a frequent complication that occurs immediately post-orthotopic liver transplantation (OLT). The Model for End-stage Liver Disease (MELD) score describes the survival of patients with ESLD awaiting OLT related to the severity of liver disease. The Simplified Acute Physiology Score (SAPS II) is a mortality prediction model that scores the severity of illness among intensive care unit patients. In a previous study we observed an association between ARF post-OLT and a higher MELD score, but it was not clear whether this association depends on the grade of ESLD or on the critical condition of liver transplant patients. The aim of this study was to evaluate the association of ARF with MELD score and/or SAPS II criteria among liver transplant patients. We analyzed 46 patients with ESLD who underwent deceased donor OLT. All patients were evaluated at baseline and in the first 7 days post-OLT. According to the RIFLE classification, the incidence of the worst grade of ARF post-OLT was 19.2%. These patients showed significantly higher MELD scores, while there was no association with systemic parameters related to the critical patients condition or with the mortality score as evaluated by SAPS II criteria. We confirmed the association between renal failure and hepatic function among liver transplant patients. A more severe degree of hepatic dysfunction before OLT was associated with a greater incidence of ARF that can adversely affect patient survival.

Conversion From Twice-Daily to Once-Daily Tacrolimus Administration in Liver Transplant Patient

BACKGROUND Compliance to immunosuppressive therapy is critical to prevent organ rejection and possible graft loss. A once-daily Tacrolimus formulation that may improve adherence-to-therapy while allowing the same patient care strategies, total daily dose and monitoring techniques that have been recently approved. The present study was sought to evaluate the feasibility of this formulation among liver transplantation patients (OLT). MATERIALS AND METHODS Patients transplanted for at least 6 months were enrolled if they had stable doses of Tacrolimus over the last 3 months. Conversion from a twice to a once-daily regimen was based on a 1 mg:1 mg proportion. Tacrolimus blood levels were assessed at 0, 15, 30, 60, 90 days as well and 6 months after conversion. We recorded liver and renal function as well as adverse events. RESULTS Among twenty-eight patients enrolled in the study including 23 males and 5 females the overall mean age was 59 +/- 8 years and the mean distance from OLT was 39 +/- 22. 32% of patients did not require any dose adjustment. In contrast, 43% required an increase (+0.6 +/- 0.3 mg/d), while 25%, a decrease (-0.5 +/- 0.0 mg/d) in the drug dose to maintain the same tacrolimus blood concentrations as at baseline. Ninety percent of patients stabilized blood levels within 45 days. None of the patients experienced adverse events or alterations in liver function. CONCLUSIONS Our study confirmed that once-daily Tacrolimus is a useful therapeutic option for OLT patients; however dose adjustments are frequently needed in the short term. The drug is safe and may improve patient compliance.

Acute Renal Failure in Liver Transplant Recipients: Role of Pretransplantation Renal Function and 1-Year Follow-Up

Chronic renal failure and acute renal failure (CRF and ARF) are common complications after orthotopic liver transplantation (OLT) that adversely affect patient survival. Many factors influence the development of ARF in the OLT setting. In a previous study we reported an association between ARF and the development of CRF at 1 month after OLT. The aims of our study were to evaluate the influence of ARF on short-, middle-, and long-term renal function after OLT and its influence on 1-year survival of patients and grafts. Fourty-four patients who underwent deceased donor OLT between August 2008 and August 2010 were evaluated pretransplantation, in the perioperative period, and at 1, 6, and 12 months posttransplantation. ARF was associated with CRF at 1 month post-OLT, whereas no association was observed at 6 and 12 months post-OLT. The development of CRF at 6 months post-OLT was associated with pre-OLT renal dysfunction and 1 month post-OLT CRF. Four patients died in the ARF group, whereas 3 patients died in the group without ARF. We confirmed ARF to be a predictive event for short-term renal dysfunction. The majority of patients recovered renal function after the first month. Although many pre-, peri-, and post-OLT factors may contribute to the development of posttransplantation CRF, pre-OLT CRF seemed to be the most important risk factor.

Combined Liver-Kidney Transplantation in Polycystic Disease: Case Reports

Polycystic disease causes a progressive decrease in renal function and liver degeneration. The progression of the disease evolves separately between organs and transplantation options vary: simultaneous or sequential liver-kidney transplantation or single-organ transplantation. From September 2006 to June 2007 3 combined liver kidney transplantations (CLKT) were performed for polycystic disease with end-stage renal disease: 2 with polycystic liver disease, and 1 with hepatic failure due to congenital hepatic fibrosis. The widest dimensions of the polycystic liver of 50 and 60 cm diameter were due to extensive cystic degeneration. We performed 1 simultaneous CLKT and 2 sequential transplantations: 1 liver after kidney, and 1 kidney after liver. At present all patients are alive with 100% graft function. Median creatinine level at discharge was 0.9 mg/dL (ranges, +/-0.2). Good liver graft function was reported in all 3 cases. Transplant benefit in polycystic liver-kidney disease has been already demonstrated; conservative surgical options may result in a high incidence of complications in highly involved polycystic livers. Delaying transplantation results in a more difficult surgical technique, a higher rate of postoperative complications, and a disturbance of optimal graft retrieval because of the worse preoperative condition of the patients.

Biliary secretion of phosphatidylcholine and its molecular species in cholecystectomized T-tube patients: effects of bile acid hydrophilicity

The aim of the present study was to establish whether the oral administration of bile acids with different hydrophilic properties affects the amount of phosphatidylcholine as well as the pattern of PC molecular species secreted in bile. We studied the biliary output of total and individual PC species in cholecystectomized T-tube patients, with a total biliary outflow, after oral administration of 750 mg of ursodeoxycholate (3 patients) or deoxycholate (3 patients). The latter experiments were repeated after 3 days of taurine supplementation (1500 mg daily) in order to increase, by means of the tauro-conjugation, the hydrophilicity of the secreted BA. A linear function was observed, during all the studies, between BA and PC biliary secretion, but the amount of PC secreted per mole of BA was higher for the less hydrophilic BA, such as deoxycholate, than for the more hydrophilic ursodeoxycholate or during deoxycholate plus taurine experiments. With regard to the pattern of PC molecular species, we observed no changes after administration of ursodeoxycholate. An increase in the secretion of the major polyenoic species (i.e., 16:0-18:2 and 16:0-20:4), with respect to the secretion of the monoenoic, was revealed during deoxycholate experiments. Conversely, during the deoxycholate plus taurine experiments, the secretion of the major monoenoic PC species (i.e., 16:0-18:1) increased more than that of the polyenoic species. We suggest that the observed modifications of the pattern of PC molecular species, secreted in bile, represent the result of a physicochemical effect of BA on liver membranes.

Preoperative donor scores and postoperative early measures of graft function: relevance to the outcome of liver transplantation.

BACKGROUND Several donor and recipient parameters play a role in the determination of post-liver transplant allograft function. The identification of prognostic indices presents great implications for correct allocation of donors and more targeted recipient management. The aim of our review was to detect the role of preoperative scoring systems and early postoperative measures of graft function as predictive factors for the development of graft failure and recipient death. METHODS We stratified a cohort of 97 patients in two groups according to a 1-year functional (Group A; n = 72) versus non-functional (Group B; n = 25) status of the allograft. RESULTS Patients in group B showed higher preoperative Model for End-stage Liver Disease (MELD) values, longer warm ischemia times, reduced bile outputs and increased peak values of transaminases and INR content within the first 3 days after transplantation. Group B showed 48% of patients with initial poor graft function. The parameters which resulted in a significant prediction of graft loss by multivariate analysis were MELD (P = .012); postoperative day 1 serum alanine aminotransferase (ALT) (P < .0001) and day 3 ALT (P = .003). The predictive factors for patient death were postoperative day 1 serum ALT (P < .0001) and day 3 ALT (P = .001). CONCLUSIONS MELD score was a useful preoperative parameter for the prediction of post-transplant graft survival. Early ALT values predicted both graft and recipient survivals. Minimization of parameters related to their peaks (warm ischemia time) may improve graft and patients survival rates.