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Biomedical subjects

B Sangro

Publications and source records attributed to B Sangro.

At least 19 recordsLinked to original sources
PubMed2006

New therapies for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC), one of the most common cancers worldwide, is often diagnosed at an advanced stage when most potentially curative therapies such as resection, transplantation or percutaneous and transarterial interventions are of limited efficacy. The fact that HCC is resistant to conventional chemotherapy, and is rarely amenable to radiotherapy, leaves this disease with no effective therapeutic options and a very poor prognosis. Therefore, the development of more effective therapeutic tools and strategies is much needed. HCCs are phenotypically and genetically heterogeneous tumors that commonly emerge on a background of chronic liver disease. However, in spite of this heterogeneity recent insights into the biology of HCC suggest that certain signaling pathways and molecular alterations are likely to play essential roles in HCC development by promoting cell growth and survival. The identification of such mechanisms may open new avenues for the prevention and treatment of HCC through the development of targeted therapies. In this review we will describe the new potential therapeutic targets and clinical developments that have emerged from progress in the knowledge of HCC biology, In addition, recent advances in gene therapy and combined cell and gene therapy, together with new radiotherapy techniques and immunotherapy in patients with HCC will be discussed.

Carcinoma, Hepatocellular↗
PubMed2004

[Treatment of chronic hepatitis B virus infection].

The treatment of the patient with chronic hepatitis B virus infection (HBV) must be carried out with the knowledge that the percentage of patients infected with the B virus that develop chronic hepatitis remains between 5-10%. Of these, 10-30% will present chronic infection with active viral replication, necroinflammatory hepatic lesion, evolution to hepatic cirrhosis and the risk of developing hepatocarcinoma. For this reason, the aim of treatment is to achieve negativisation of the HBeAg, seroconversion to anti-HBe and a reduction of viral replication to undetectable values (estimated by level of DNA-HBV), for protracted periods of time. When a sustained loss of HBeAg and a reduction of viral replication are obtained, a biochemical, clinical and histological remission is achieved. Up until now the therapeutic alternatives in chronic infection by the B virus have been immunomodulation with Interferon alpha and the blocking of viral replication with lamivudine or adefovir dipivoxil. A difference must be drawn between the biochemical response, defined as a fall in the transaminases to normal values, and the virological response, which refers to a fall in the levels of DNA-HBV below 10(5) copies/ml. Finally, the complete response is defined as the virological and biochemical response with negativisation of the HBsAg. If a sustained response is obtained for several months, a histological response can be predicted with reduction in the intensity of the hepatic lesion and an absence or stabilisation in the process of fibrosis. The sustained response should last for no less than 6 to 12 months following the end of treatment.

Adenine↗
PubMed2003

Conversion from calcineurin inhibitors to mycophenolate mofetil in liver transplant recipients with diabetes mellitus.

Diabetes mellitus, a frequent metabolic complication in liver transplant recipients, may be produced by the diabetogenic effect of calcineurin inhibitors cyclosporine and tacrolimus. The aim of this study was to investigate the safety and metabolic effects of a gradual switch from cyclosporine or tacrolimus to mycophenolate mofetil among 12 diabetic liver transplant recipients. One patient was withdrawn from the study due to gastrointestinal side effects. Of the 11 remaining patients, cyclosporine or tacrolimus was completely withdrawn in five patients. Two patients developed suspected acute rejection episodes that were controlled by increasing the tacrolimus dosage. Glycosylated hemoglobin A1C and C-peptide levels were significantly lower at 3 and 6 months after the initiation of mycophenolate mofetil (P<.03 in all cases). Furthermore, urea and uric acid levels were significantly reduced after the change of treatment. In conclusion, a switch from cyclosporine/tacrolimus to mycophenolate mofetil may produce beneficial metabolic effects in diabetic liver transplant recipients, but poses a risk of graft rejection.

Blood Glucose↗
PubMed2003

The promise of gene therapy in gastrointestinal and liver diseases.

Gene therapy consists of the transfer of genetic material to cells to achieve a therapeutic goal. In the field of gastroenterology and hepatology gene therapy has produced considerable expectation as a potential tool in the management of conditions that lack effective therapy including non-resectable neoplasms of the liver, pancreas and gastrointestinal tract, chronic viral hepatitis unresponsive to interferon therapy, liver cirrhosis, and inflammatory bowel disease.

Animals↗
PubMed2003

Suicide gene therapy mediated by the Herpes Simplex virus thymidine kinase gene/Ganciclovir system: fifteen years of application.

Gene-directed enzyme prodrug therapy (GDEPT) is a two step therapeutic approach for cancer gene therapy. In the first step, the transgene is delivered into the tumor and expressed. In the second step a prodrug is administered and is selectively activated by the expressed enzyme. The first GDEPT system described was the thymidine kinase gene of the Herpes Simplex virus (HSVtk) in combination with the prodrug Ganciclovir (GCV). A large number of experiments have been performed with this system, in different types of tumors and initial studies in animal models were very promising. This encouraged investigators to move into clinical trials although poor results have been obtained so far. A large effort has been made with numerous different strategies to enhance HSVtk/GCV efficacy in cellular and in vivo models and very strong cytotoxic effects have been obtained. The present review describes the current state of preclinical research and summarizes the results of the clinical trials undertaken.

Cell Death↗
PubMed2002

Gene therapy for liver diseases: recent strategies for treatment of viral hepatitis and liver malignancies.

Gene therapy has emerged as a powerful and very plastic tool to regulate biological functions in diseased tissues with application in virtually all medical fields. An increasing number of experimental and clinical studies underline the importance of genes as curative agents in the future. However, intense research is needed to evaluate the potential of gene therapy to improve efficacy and minimise the toxicity of the procedure.

Clinical Trials, Phase I as Topic↗
PubMed2001

Genetic heterogeneity in the toxicity to systemic adenoviral gene transfer of interleukin-12.

Despite the efficacy of IL-12 in cancer experimental models, clinical trials with systemic recombinant IL-12 showed unacceptable toxicity related to endogenous IFNgamma production. We report that systemic administration of a recombinant adenovirus encoding IL-12 (AdCMVmIL-12) has a dramatically different survival outcome in a number of mouse pure strains over a wide range of doses. For instance at 2.5 x 10(9) p.f.u., systemic AdCMVmIL-12 killed all C57BL/6 mice but spared all BALB/c mice. Much higher IFNgamma concentrations in serum samples of C57BL/6 than in those from identically treated BALB/c were found. Causes for heterogeneous toxicity can be traced to differences among murine strains in the levels of gene transduction achieved in the liver, as assessed with adenovirus coding for reporter genes. In accordance, IL-12 serum concentrations are higher in susceptible mice. In addition, sera from C57BL/6 mice treated with AdCMVmIL-12 showed higher levels of IL-18, a well-known IFNgamma inducer. Interestingly, lethal toxicity in C57BL/6 mice was abolished by administration of blocking anti-IFNgamma mAbs and also by simultaneous depletion of T cells, NK cells, and macrophages. These observations together with the great dispersion of IFNgamma produced by human PBMCs upon in vitro stimulation with IL-12, or infection with recombinant adenovirus encoding IL-12, suggest that patients might also show heterogeneous degrees of toxicity in response to IL-12 gene transfer.

Adenoviridae↗
PubMed2001

Gene therapy of orthotopic hepatocellular carcinoma in rats using adenovirus coding for interleukin 12.

The use of gene therapy to enhance antitumor immunity has emerged as a promising procedure to fight cancer. In this study we have tested the ability of an adenovirus carrying interleukin 12 (IL-12) gene (AdCMVIL-12) to eliminate tumoral lesions in 3 animal models of orthotopic hepatocellular carcinoma (HCC). Intratumoral injection of AdCMVIL-12 in animals with a single big tumor nodule implanted in the liver resulted in significant inhibition of tumor growth in a dose-dependent manner. Fifty percent of animals that received a dose of 5 x 10(9) plaque-forming units, showed complete regression of the tumor 2 weeks after treatment. In animals with 2 independent tumor nodules in the left liver lobe, injection in only one of them of 5 x 10(9) pfu AdCMVIL-12 induced, 15 days after therapy, complete regression of 50% of treated tumors and also of 50% of untreated lesions, with 60% long-term survival. Rats that were tumor free after therapy with AdCMVIL-12 showed protection against tumor rechallenge. A group of rats received the carcinogen diethylnitrosamine and developed multiple hepatic dysplasic nodules of 1 to 5 mm in diameter. These animals were treated by intrahepatic artery injection of either AdCMVIL-12 (5 x 10(9) pfu) or control vector. In this model AdCMVIL-12 induced complete tumor regression in 20% of treated rats and inhibited tumor growth in 60% of cases with an increase in rat survival. Activation of natural killer (NK) cells and inhibition of angiogenesis were found to be antitumor mechanisms set in motion by AdCMVIL-12. Our data indicate that experimental HCC can be efficiently treated by intratumoral or intravascular injection of adenovirus expressing IL-12.

Adenoviridae↗
PubMed2001

Liver transplantation in cirrhotic patients with diabetes mellitus: midterm results, survival, and adverse events.

Liver cirrhosis is frequently associated with diabetes mellitus (DM), and this metabolic complication is also frequent after orthotopic liver transplantation (OLT). The aim of our study is to investigate which factors are associated with DM before and after OLT and their impact on post-OLT evolution. We evaluated the prevalence of DM among 115 liver transplant candidates with cirrhosis and assessed their evolution after OLT (median follow-up, 41 months). Sixteen candidates had DM requiring pharmacological therapy (group A), 45 candidates had DM controlled with diet (group B), and 54 candidates did not have DM (group C). One-year and 3-year actuarial survival rates were 100% and 100% for group A, 91% and 85% for group B, and 77% and 74% for group C, respectively (P <.03). Post-OLT DM was more frequent in group A. The incidence of other metabolic complications, major infections, rejection, and arterial hypertension; the need for hospitalization; and renal and graft function of patients in groups A, B, and C were similar. The only risk factor for DM 1 year after OLT on multivariate analysis was pre-OLT DM requiring pharmacological treatment. The incidence of complications, need for hospitalization, and renal and graft function 1 year after OLT for patients with post-OLT DM were similar to those of patients without post-OLT DM. In conclusion, patients with cirrhosis who have DM have a greater risk for post-OLT DM, but their midterm survival is not worse than the survival of those without DM.

Adult↗
PubMed2001

Prognostic model for early acute rejection after liver transplantation.

Hepatic graft rejection is a common complication after liver transplantation (LT), with a maximum incidence within the first weeks. The identification of high-risk patients for early acute rejection (EAR) might be useful for clinicians. A series of 133 liver graft recipients treated with calcineurin inhibitors was retrospectively assessed to identify predisposing factors for EAR and develop a mathematical model to predict the individual risk of each patient. The incidence of EAR (< or =45 days after LT) was 35.3%. Multivariate analysis showed that recipient age, underlying liver disease, and Child's class before LT were independently associated with the development of EAR. Combining these 3 variables, the following risk score for the development of EAR was obtained: EAR score [F(x)] = 2.44 + (1.14 x hepatitis C virus cirrhosis) + (2.78 x immunologic cirrhosis) + (2.51 x metabolic cirrhosis)--(0.08 x recipient age in years) + (1.65 x Child's class A) [corrected]. Risk for rejection = e(F(x))/1 + e(F(x)). The combination of age, cause of liver disease, and Child's class may allow us to predict the risk for EAR.

Calcineurin Inhibitors↗
PubMed2001

Influence of tumor characteristics on the outcome of liver transplantation among patients with liver cirrhosis and hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) may recur after liver transplantation (LT), mainly in patients with multinodular and large tumors. However, factors predictive of outcome after LT in patients with small tumors remain ill defined. We investigated which factors were related to mortality or tumor recurrence among 47 liver transplant recipients with liver cirrhosis and HCC and compared them with 107 patients with liver cirrhosis without tumor who underwent LT in the same period. Patients with HCC were older (P <.001), more frequently had cirrhosis of a viral origin (P <.001), and had lower Child-Pugh scores (P <.001) than patients without tumor. Survival of patients with and without tumor was not significantly different (P =.20). Among patients with HCC, those with lower recurrence-free survival rates had liver cirrhosis of a viral origin, vascular invasion, bilobar disease, and tumor-node-metastasis (TNM) stage IV. At multivariate analysis, the only factor associated with mortality or recurrence was TNM stage IV (P =.02). Our results suggest that in patients with HCC and TNM stage IV, LT might be contraindicated.

Adult↗
PubMed2001

Gene therapy of hepatocellular carcinoma.

The extraordinary versatility of gene therapy opens new possibilities for the treatment of incurable diseases, including hepatocellular carcinoma. Gene therapy strategies against tumors include prodrug activation therapy by the transfer of suicide genes, immunogene therapy, tumoral cell phenotype correction by the inhibition of oncogenes or the transfer of tumor suppressor genes, antiangiogenesis and transfer of oncolytic viruses. The experience accumulated during the last decade of clinical gene therapy indicates that genes can be expressed inside the tumor tissue, but the overall results of the studies conducted so far are still disappointing, mainly due to the poor performance of the currently available gene therapy vectors. This review covers the general aspects of gene therapy vectors, preclinical data available in animal models of hepatocellular carcinoma, and finally a brief summary of the gene therapy clinical trials aimed at the treatment of liver cancer.

Animals↗
PubMed2000

Liver damage using suicide genes. A model for oval cell activation.

Liver regeneration from the facultative hepatic stem cells, the oval cells, takes place in situations in which liver regeneration from pre-existing hepatocytes is prevented. Different models have been used to stimulate oval cell response. Many of them involve the use of carcinogenic agents with or without partial hepatectomy. In this study we show that adenovirus-mediated gene transfer of the suicide gene thymidine kinase followed by ganciclovir administration caused hepatotoxicity of variable intensity. Rats with moderate elevation in serum transaminases recovered normal liver architecture few weeks after adenovirus injection. In contrast, rats with severe liver damage exhibited a marked and persisting activation of oval cells accompanied by ductular hyperplasia. In some rats, such lesion eventually evolved to cholangiofibrosis and in one rat to cholangiocarcinoma. Deposition of fibronectin and increased number of hepatic stellate cells were found in association with oval cells and cholangiofibrotic lesions. Hepatocyte growth factor was hyperexpressed in the livers with intense oval cell response or ductular proliferation, suggesting a participation of this factor in those lesions. In summary, our data demonstrate activation of oval cell response after gene transfer of thymidine kinase followed by ganciclovir administration. These findings indicate that high doses of this therapy causes liver damage together with an impairment in hepatocellular regeneration.

Adenoviridae↗
PubMed2000

Hyperhomocysteinemia in liver transplant recipients: prevalence and multivariate analysis of predisposing factors.

Liver transplant recipients have an increased risk for cardiovascular disease because of a high incidence of obesity, arterial hypertension, diabetes mellitus, and hyperlipidemia. Hyperhomocysteinemia has been found to be an important risk factor for cardiovascular disease in large studies. Fasting serum levels of homocysteine were measured in 105 liver transplant recipients, and hyperhomocysteinemia was defined as a fasting serum homocysteine level greater than 13 micromol/L. Patients with versus without hyperhomocysteinemia were compared. The possible association of hyperhomocysteinemia with age, sex, cause of liver disease, time elapsed since liver transplantation, immunosuppressive therapy, folic acid level, liver function test results, renal function, and other cardiovascular risk factors was investigated. Patients with serum homocysteine levels greater than 15 micromol/L were treated with folic acid, 10 mg/d, and serum homocysteine levels were measured again 1 to 3 months later in 10 patients. Hyperhomocysteinemia was detected in 28 patients (27%). In univariate analysis, it was associated with hepatitis C virus infection, treatment with mycophenolate mofetil, and greater serum levels of alkaline phosphatase, gamma-glutamyl transpeptidase, urea, and creatinine. In multivariate analysis, only greater serum levels of creatinine (P =.006) were associated with hyperhomocysteinemia. Treatment with folic acid resulted in a decrease in fasting serum homocysteine levels in 9 of the 10 patients tested (P =.01). Hyperhomocystinemia, associated with renal dysfunction, is a frequent finding in liver transplant recipients. Treatment with folic acid may reduce fasting homocysteine levels.

Creatinine↗
PubMed2000

Aortic valve replacement with bioprostheses in liver transplant recipients.

Three cases of aortic valve replacement with porcine bioprostheses are reported in liver transplant recipients at two to six years after transplantation. Indications for aortic valve replacement (AVR) were aortic stenosis (n = 2) and aortic regurgitation (n = 1). The use of bioprostheses was recommended because of patient age, the need for multiple liver biopsies, and contraindication to the use of anticoagulation therapy. The patient who underwent AVR because of aortic regurgitation developed structural valve deterioration (SVD) during the next five years after surgery, and thus replacement of the bioprosthetic valve was required. Recipients of liver transplant who undergo valve replacement with tissue valves should be carefully followed up because of the risk of early SVD. AVR may be performed safely after liver transplantation.

Adult↗