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Paolo Carraro

Publications and source records attributed to Paolo Carraro.

14 recordsLinked to original sources
PubMed2006

Metabolic activity of rat hepatocytes cultured on homologous acellular matrix and transplanted into Gunn rats.

The metabolic activity of hepatocytes cultured on homologous acellular matrix (HAM) and transplanted into rats genetically incapable of bilirubin conjugation (Gunn rats) has been investigated. Hepatocytes from Wistar male rats were seeded on HAM and cultured for 9 days, and the proliferation rate and albumin mRNA expression were assayed daily. HAM alone or HAM plus hepatocytes (cultured for 3 days) were implanted in a subcutaneous pocket of the dorsal region of Gunn rats. No immunosuppression therapy was used. Blood samples were collected weekly and rats were sacrificed 10 weeks after surgery. Hepatocytes cultured on HAM displayed a higher proliferation rate than those cultured on plastic, and albumin mRNA expression was detected in hepatocytes seeded on HAM, but not on plastic. Serum bilirubin concentrations did not differ from baseline values in both the sham-operated control and HAM transplanted rats. On the contrary, in rats transplanted with HAM plus hepatocytes, circulating bilirubin levels decreased from week 4-7, and then plateaued until week 10. Histology did not evidence signs of rejection, but only a mild degree of inflammation around the implanted patches. It is concluded that hepatocytes seeded on HAM and transplanted into Gunn rats are able to metabolize bilirubin for at least two months, without signs of rejection even in the absence of immunosuppressive therapy.

Animals↗
PubMed2005

Effects of long-term administration of high-dose recombinant human antithrombin in immunosuppressed primate recipients of porcine xenografts.

BACKGROUND: Fibrin deposition is central to the acute humoral rejection process occurring in the presence of consumptive coagulopathy when pig organs are transplanted into primates. METHODS: To assess whether strategies aimed at preventing fibrin formation may extend xenograft survival, we administered high daily doses of recombinant human antithrombin (rhAT) (500 U/kg twice daily) to obtain both anticoagulant and anti-inflammatory effects in immunosuppressed primate recipients of porcine kidneys. RESULTS: Some degree of consumptive coagulopathy developed in both rhAT-treated (n=3) and untreated (n=3) primates. No major differences in the coagulation parameters analyzed were observed between the 2 groups. Similarly, no difference in survival was seen between rhAT-treated (20.6+/-4 days; range: 15-23 days) and untreated animals (17.3+/-11.6 days; range: 7-30 days), although the rhAT-treated primates had a higher bleeding tendency. Despite the high daily dose of rhAT, considerable fibrin deposition was observed in the graft as early as 2 weeks after transplantation. CONCLUSIONS: These results suggest that a high daily dose of rhAT fails to influence survival or prevent fibrin formation and deposition in the graft in our pig-to-primate model. However, the potential role of rhAT administered in combination with heparins or other clotting inhibitor concentrates in this model remains to be determined.

Animals↗
PubMed2005

Syngeneic living-donor liver transplantation for hemangioendothelioma: a clinical model for studying liver regeneration.

A 22-year-old Caucasian patient underwent living-donor liver transplantation (LDLT) for hepatic hemangioendothelioma in a healthy liver. The organ donor was his monozygotic twin brother. Surgery was uneventful in both donor and recipient, who received the same postoperative treatment (i.e. no immunosuppression for the recipient). Although both donor and recipient achieved a full liver function recovery, the volume of the recipient's graft increased much more than the donor's residual liver in the first postoperative month (1.6-fold vs. 1.2-fold). This different growth rate correlated with growth hormone (GH)/insulin growth factor (IGF) axis dynamics: the donor had significantly lower insulin-like growth factor 1 (IGF-1), insulin-like growth factor 2 (IGF-2) and insulin-like growth factor binding protein 3 (IGFBP-3) values than the recipient on postoperative days (POD) 3-30, although they had similar GH values. Other potential regenerative factors, e.g. tumor necrosis alpha, interleukin 6 (IL-6), insulin and C peptide did not correlate with liver regeneration rate. The particular endocrine picture of the graft may be explained by a modified GH-hepatocyte interaction due to cold ischemia during preservation resulting in a higher IGF production. Whether this is a potential molecular tool by means of which transplanted partial livers promote their regeneration remains to be seen in a larger number of patients.

Adult↗
PubMed2005

Isolated hepatocyte transplantation for Crigler-Najjar syndrome type 1.

Crigler-Najjar syndrome type 1 (CN1) is an inherited disorder characterized by the absence of hepatic uridine diphosphoglucuronate glucuronosyltransferase (UDPGT), the enzyme responsible for the conjugation and excretion of bilirubin. We performed allogenic hepatocyte transplantation (AHT) in a child with CN1, aiming to improve bilirubin glucuronidation in this condition. A 9-year-old boy with CN1 was prepared with plasmapheresis and immunosuppression with prednisolone and tacrolimus. When a graft was made available, 7.5 x 10(9) hepatocytes were isolated and infused into the portal vein percutaneously. After 2 weeks phenobarbitone was added to promote the enzymatic activity of UDPGT of the transplanted hepatocytes. Nocturnal phototherapy was continued throughout the studied period. Total bilirubin was considered a reliable marker of allogenic cell function. There was no significant variation of vital signs nor complications during the infusion. Mean +/- SD bilirubin level was 530 +/- 38 micromol/L before and 359 +/- 46 micromol/L after AHT (t-test, p < 0.001). However, the introduction of phenobarbitone was followed by a drop of tacrolimus level with increase of alanine aminotransferase (ALT) and increase of bilirubin. After standard treatment of cellular rejection bilirubin fell again but from then on it was maintained at a greater level. After discharge the patient experienced a further increase of bilirubin that returned to predischarge levels after readmission to the hospital. This was interpreted as poor compliance with phototherapy. Only partial correction of clinical jaundice and the poor tolerability to nocturnal phototherapy led the parents to refuse further hepatocyte infusions and request an orthotopic liver transplant. After 24 months the child is well, with good liver function on tacrolimus and prednisolone-based immunosuppression. Isolated AHT, though effective and safe, is not sufficient to correct CN1. Maintenance of adequate immunosuppression and family compliance are the main factors hampering the success of this procedure.

Child↗
PubMed2004

Clinical significance of alpha-fetoprotein mRNA in blood of patients with hepatocellular carcinoma.

BACKGROUND: Alpha-fetoprotein (AFP) messenger RNA (mRNA) in the blood reflects the presence of circulating hepatocellular carcinoma (HCC) cells and is a sensitive marker of HCC extrahepatic metastases. The specificity of this molecular marker and its correlation with the main HCC clinical-pathological parameters remains controversial, however. METHODS: AFPmRNA was determined in 50 HCC patients and in 50 patients with diagnosis of cirrhosis (6), or colon (24) or, pancreatic (20) carcinoma. HCC patients with clinically evident extrahepatic metastasis were excluded. HCC diagnosis was confirmed in all patients by histology on percutaneous biopsies or surgical specimens; pathological grading was assessed at the same time. RESULTS: AFPmRNA was positive in 20 HCC patients (40%) and in 18 patients without HCC (36%). The presence of AFPmRNA in the blood correlated significantly with cholestatic indices (p<0.01), nodule size (p=0.03), vascular invasion (p=0.006) and moderately or poorly differentiated HCC (p<0.0001). Moreover, survival analysis showed a significant impact of AFPmRNA detection on overall (p=0.04) and recurrence-free survival (p=0.0007) after a median follow-up of 17 months. CONCLUSIONS: Although AFPmRNA is frequently detected in the blood, even in benign liver diseases or gastroenteric tumors, in HCC patients without clinical evidence of extrahepatic metastases it seemed to identify the biologically more aggressive tumors.

Adult↗
PubMed2003

Appropriateness of choice and interpretation of tests for thrombophilic defects: a practical experience.

BACKGROUND: The use of laboratory coagulation tests in some fields of primary medicine is not well defined in available guidelines. In Italy, general practitioners tend to lack a thorough understanding of the utility of knowledge of coagulation inhibitors. METHODS: We reviewed the clinical conditions for which outpatients have been referred to our laboratory for antithrombin testing or for inherited thrombophilia tests panels over a 3-week period. Evidence-based guidelines were used to identify the appropriate requests. RESULTS: Numerous unnecessary tests were requested for both antithrombin and thrombophilia, particularly in obstetric and gynaecological situations in the setting of hormonal contraceptive treatment. CONCLUSIONS: Laboratory specialists must improve upon their communication with physicians in order to achieve an appropriate use of coagulation tests.

Blood Coagulation Tests↗
PubMed2003

Methotrexate for immunosuppression in life-supporting pig-to-cynomolgus monkey renal xenotransplantation.

Methotrexate (MTX) has been used successfully as an immunosuppressant in rodent xenotransplantation models, but the data generated so far with MTX in pig-to-baboon cardiac transplantation studies have been disappointing. The potential of this agent was consequently explored in a life-supporting pig-to-primate renal model using the cynomolgus monkey as the recipient species. Introductory in vitro and in vivo pharmacokinetic and pharmacodynamic studies with MTX were conducted in three cynomolgus monkeys. Subsequently, 10 cynomolgus monkey recipients of a life-supporting kidney from human decay-accelerating factor transgenic pigs were administered MTX intravenously according to three different regimens. All the animals also received cyclosporine A and steroids. In addition, mycophenolate sodium (MPS) was administered post-operatively in two of the three groups of transplanted animals. At clinically relevant concentrations, MTX is able in vitro to inhibit the mixed lymphocyte reactions (MLR) in cynomolgus monkeys. After intravenous administration, moreover, exposure of cynomolgus monkeys to MTX appeared to be higher than had been previously reported in baboons. Graft function was observed in the transplanted animals, which survived from 0 to 41 days. All but two animals revealed acute humoral rejection in the explanted graft and developed diarrhea. Diarrhea was the cause of euthanasia in five cases. It was unrelated to the administration of MPS and associated with severe histopathological signs of enteritis. This study demonstrates that the pharmacokinetic and pharmacodynamic profiles if MTX vary substantially between non-human primate species. In vitro, MTX has immunosuppressive properties in the cynomolgus monkey at clinically relevant concentrations. In vivo, MTX has a very narrow therapeutic window in cynomolgus monkeys, however, as it does in baboons. We conclude that MTX is scarcely effective as an immunosuppressant, be it for induction or maintenance, in pig-to-cynomolgus monkey renal xenotransplantation.

Animals↗
PubMed2003

Guidelines for the laboratory investigation of inherited thrombophilias. Recommendations for the first level clinical laboratories.

Recent advances in the laboratory diagnostic approach to inherited thrombophilia call for an update on laboratory strategies and organization. The present paper therefore deals in particular with: the panel test choice, timing and test appropriateness, and analytical methods in several clinical conditions. Specific recommendations are supported by the state-of-the-art in this branch.

Antithrombin III Deficiency↗
PubMed2003

Hepatocyte transplantation in the treatment of acute liver failure: microencapsulated hepatocytes versus hepatocytes attached to an autologous biomatrix.

A liver transplant is considered today to be the only effective therapeutic solution for many otherwise intractable hepatic disorders. However, liver transplantation is beset by shortage of donors. Over the years, many liver support systems have been developed to supply the liver functions, mostly as a bridge to transplantation. Transplantation of isolated hepatocytes (HcTx) instead of whole liver has constituted one of the most appealing possibilities to treat several diseases. We compared two different models of HcTx in a surgical model of acute liver failure in pigs, using microencapsulated hepatocytes (MHcTx) and hepatocytes attached to a porcine biomatrix (PBMHcTx), both transplanted into peritoneum. The collected data were survival, laboratory findings, hemodynamic parameters, light microscopy, histology, MTT, and glycogen content. The group with PBMHcTx has a better outcome than the group with MHcTx (p < 0.05). Histology showed normal morphology of the hepatocytes, high glycogen content, 75% viability, positive MTT, and 95% adhesion of the hepatocytes to the biomatrix. Our biomatrix (PBM) provides cell-to-cell contact and interaction with extracellular matrix, which have been shown to play major roles in hepatocyte survival and physiologic regulation of gene expression, and guarantee a prompt engraftment and an adequate neovascularization. PBMHcTx is a useful method to treat acute liver failure and it indicates a possible liver-direct gene therapy in the treatment of inherited and acquired disorders.

Animals↗
PubMed2003

Peripheral artery disease in type 2 diabetes: the role of fibrinolysis.

The aim of the present study is to verify the relationship between peripheral artery disease (PAD) and some coagulation/fibrinolysis parameters in type 2 diabetic patients. Sixty-three type 2 diabetic patients, without PAD, were studied at baseline and after 4 years. Assessments included tissue-Plasminogen Activator (t-PA), Plasminogen Activator Inhibitor-1 antigen (PAI-1 Ag), Plasminogen Activator Inhibitor-1 activity (PAI-1 Act), Plasminogen (Pl), Fibrin peptide A (FPA), Fibrinogen (Fr), and the ankle/brachial pressure index (ABI). We observed a significant difference between diabetic patients and controls as regards tPA (11.8 +/- 5.4 vs. 6.6 +/- 3.0 ng/ml; p <0.05) and PAI-1 Act (17.8 +/- 9.2 vs. 11.7 +/- 6.6 ng/dl; p <0.005). After 4 years 13 diabetic patients became vasculopathic and, at baseline, had significantly lower tPA (8.9 +/- 4.8 vs. 12.5 +/- 5.3; p <0.011), and higher PAI-1 Ag (50.8 +/- 22.2 vs. 32 +/- 22.2; p <0.006), and PAI-1 Act values (24.1 +/- 9.5 vs. 16.1 +/- 8.4; p <0.014), compared with 50 diabetic patients who did not develop PAD after 4 years. These data show that the physiological equilibrium which exists between t-PA and PAI-1 moves towards higher levels in our diabetic patients compared with controls, at baseline, whereas diabetic patients who developed PAD showed a shift towards an antifibrinolytic pathway with diminished t-PA, increased PAI-1 Ag and PAI-1 Act and consequently procoagulant activity. Our study suggests that hypofibrinolysis may be involved in the future onset of PAD in type 2 diabetic patients.

Aged↗
PubMed2003

Cytokines and liver failure: modification of TNF- and IL-6 in patients with acute on chronic liver decompensation treated with Molecular Adsorbent Recycling System (MARS).

Liver transplantation, considered today as the most effective treatment for end-stage liver diseases, can not always be performed on every patient affected with a liver disease. Patients with end-stage liver diseases, usually have high bilirubin, encephalopathy and renal failure. In these situations cytokines play an important role in different processes, from apoptosis to regeneration. The aim of this clinical study has been to analyse the action of new artificial liver system, called Molecular Adsorbent Recycling System (MARS) on cytokines metabolism in patients affected with acute on chronic liver failure. The results are intriguing because an increase of IL-6 and a decrease of TNF-alpha observed during MARS treatment. The study confirms the efficacy of MARS therapy in terms of homeostasis of the cytokines network and suggests an usefulness of monitoring their level during liver failure.

Adsorption↗
PubMed2002

SiO(2) entrapment of animal cells: liver-specific metabolic activities in silicaoOverlaid hepatocytes.

Rat hepatocytes in a collagen-gel sandwich configuration were exposed to silicon alkoxides in a gas phase, yielding a 0.05 to 0.15 microm porous silica layer on the gel surface. Cell viability was unaffected by the procedure. After 24 h, bilirubin conjugation, ammonia removal, urea synthesis, and diazepam metabolism were unaffected by the procedure. However, both the ammonia removal rate and diazepam metabolism were increased after 48 hr, whereas urea synthesis was unaffected. These data indicate that silica overlay allows efficient metabolic activity of collagen-gel entrapped hepatocytes. The fact that the KM of bilirubin conjugation was unaffected by the presence of the silica membrane suggests that the transport of albumin-bound substrates is not decreased. The enhancement in some metabolic activities found 48 h after the entrapment procedure may be the result of favorable changes in the hepatocyte microenvironment. These characteristics might be useful for the development of organotypical bioartificial liver devices.

Ammonia↗
PubMedDate not supplied

Development of a new bioartificial liver using a porcine autologous biomatrix as hepatocyte support.

Long-term maintenance of hepatocyte viability and differentiated function expression is crucial for bioartificial liver support. The maintenance of hepatocyte function in a bioreactor is still a problem. A major advance was the recognition that hepatocytes in attachment cultures can maintain their differentiation longer. To restore hepatocyte polarity and prolong their function, we developed a new bioreactor with a cross-flow geometry configuration and an original hepatocyte extracellular autologous biomatrix (Porcine Bio-Matrix) support. To test this new bioreactor, we compared it with a standard bioartificial liver cartridge in a suitable surgical model of acute liver failure in pigs. In our model, we performed a total hepatectomy, followed by partial liver transplantation after an 18 hour anhepatic phase. The results showed that the bioreactor containing the biomatrix was able to bridge the animal to transplantation and to sustain the transplanted liver until all function recovered (80% of animals survived, p = 0.0027). No animal survived more than 24 hours after liver transplantation in the group treated with the traditional bioartificial liver, whereas hepatocyte viability on the Porcine Bio-Matrix was 65% after 12 hours of treatment. The results suggest that our biomatrix is a suitable cell support and guarantees long-term maintenance of metabolic activity of hepatocytes. Further studies are needed, but the results obtained with this new three-dimensional bioreactor are promising, and its potential is attractive.

Animals↗