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J Prieto

Publications and source records attributed to J Prieto.

At least 73 records · Page 4Linked to original sources
PubMed2001

IL-12 gene therapy for cancer: in synergy with other immunotherapies.

In preclinical models of cancer, gene therapy with interleukin 12 (IL-12) has reached unprecedented levels of success when combined with immunotherapy approaches such as gene transfer of other cytokines and/or chemokines, costimulatory molecules or adoptive cell therapy. These combinations have been found to produce synergistic rather than additive effects. Meanwhile, IL-12 gene therapy is beginning clinical testing as a single agent, but combination strategies are at hand.

4-1BB Ligand↗
PubMed2001

Disturbed synthesis of insulinlike growth factor I and its binding proteins may influence renal function changes in liver cirrhosis.

Insulinlike growth factor-1 (IGF-1) is an anabolic hormone synthesized by the liver upon stimulation by growth hormone (GH). IGF-1 exerts important effects on renal hemodynamics and renal sodium handling. The bioactivity of this hormone is influenced by its binding proteins (BP) of which IGF-BP3 favors retention in the capillary lumen while IGF-BP1 facilitates the transport to the target tissues. IGF-BP1 modulates the actions of IGF-1 on target cells including renal tubules. Although a number of reports have dealt with disturbances of the IGF-1/IGF-BP system in cirrhosis, no studies have yet addressed the relationship between alterations in this system and renal function changes in cirrhosis. In the present study we have included 20 patients with cirrhosis and 10 healthy subjects (control group). As compared with the controls, patients showed lower circulating levels of IGF-1 and IGF-BP3, higher IGF-BP1 levels, and a tendency to higher insulinemia and GH values. The index IGF-1 x IGF-BP1/IGF-BP3 (IGF-1-IGF-BP index, reflecting the accessibility of circulating IGF-1 to target cells) was higher in patients with ascites. IGF-1 directly correlated with renal blood flow (P < 0.05), with IGF-BP3 (P < 0.001) and inversely with the Pugh's score (P < 0.02). A negative correlation was found between IGF-1-IGF-BP index and fractional sodium excretion (P < 0.01) and between IGF-BP1 and urinary sodium excretion (P < 0.02). Our findings support the hypothesis that the disturbance of the IGF-1/IGF-BP axis may be related to the degree of renal vasodilation and renal sodium retention in cirrhotic patients.

Female↗
PubMed2001

Insulin-like growth factor-I restores the reduced somatostatinergic tone controlling growth hormone secretion in cirrhotic rats.

BACKGROUND/AIMS: An altered growth hormone/insulin-like growth factor-I (GH/IGF-I) axis occurs in advanced liver cirrhosis, characterised by diminished serum levels of IGF-I and increased concentrations of GH. Under normal conditions, GH release is mediated by somatostatin (SS) inhibition. However, the influence of SS on GH release in cirrhosis is not well known. IGF-I supplementation has beneficial effects in experimental cirrhosis, and - under physiological conditions - IGF-I increases SS, inhibiting GH. The aims of this work were to study SS tone in cirrhotic animals and to evaluate whether IGF-I treatment influences SS tone, controlling GH secretion in cirrhosis. METHODS: We studied the influence of SS on GH secretion by assessing GH response to pyridostigmine (PD) in cirrhotic rats treated and untreated with IGF-I. Liver cirrhosis was induced with CCl4-inhalation for 11 weeks in male Wistar rats. The animals were randomly divided into two groups: CI+IGF (n=12), which received IGF-I treatment for 12 days (2 microg/100 g body wt-1 x d-1) and CI (n=12), which received saline. Healthy controls (CO, n=12) were studied at the same time. On day 13, animals from each group were subdivided into two groups (n=6) in order to explore the effect of a PD intrajugular bolus (10 microg x 100 gbw-1) on serum GH levels (at 0,10,20,30 and 60 min), which were assessed by RIA. RESULTS: PD bolus did not exert any effect on GH serum levels in the CI group, suggesting a low SS tone in cirrhotic rats. However, PD induced an increase in GH levels into CO and CI+IGF groups. In conclusion, as occurs under normal conditions, the cholinergic system is a significant modulator of GH secretion in experimental liver cirrhosis. CONCLUSION: Cirrhotic rats have a reduced somatostatinergic tone which can be restored by IGF-I supplementation, suggesting that somatostatin is the main factor involved in the feed-back regulation between GH and IGF-I in cirrhosis.

Administration, Inhalation↗
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

Cytokine mRNA expression in patients with mild allergic asthma following low dose or cumulative dose allergen provocation.

BACKGROUND: Allergen provocation is a very useful way to study the inflammatory response in asthmatic patients. Although cumulative dose regimens are most often applied, another provocation model with repeated inhalations of low doses of allergens has recently come into use. OBJECTIVE: We were interested to compare these two allergen provocation models. To evaluate the inflammation induced by either model, we examined the mRNA expression of several cytokines that are implicated in the orchestration of the inflammatory response observed in asthma. METHODS: Interleukin (IL)-4, IL-5, IL-13 and interferon (IFN)-gamma mRNA expression was analysed in bronchoalveolar lavage (BAL) cells and peripheral blood (PB) CD4+ and PB CD8+ T cells following any of the two provocation regimens. IL-4 and IFN-gamma mRNA expression was analysed by a competitive reverse transcriptase-polymerase chain reaction (RT-PCR) method, while IL-5 and IL-13 were analysed semiquantitatively, before and after allergen provocation with either model. RESULTS: After low dose provocations none of the cell populations studied showed a clear change in the pattern of IL-4 or IFN-gamma gene expression. In contrast, after cumulative dose provocation there was a clear tendency towards an increased IL-4 mRNA expression in BAL cells, correlating with a significant increase in IL-4 mRNA in PB CD4+ as well as in CD8+ T cells (P = 0.005 and P = 0.04, respectively). Regardless of the allergen provocation method used, in PB IL-4 mRNA was preferentially expressed by CD4+ cells while IFN-gamma was expressed more by CD8+ cells. IL-5 transcripts increased after low dose provocations in PB CD4+ T cells in six of eight patients, while after cumulative dose provocation IL-5 mRNA increased in BAL cells in six out of nine patients but decreased especially in PB CD8+ T cells in six out of eleven patients, suggesting an accumulation of IL-5 expressing cells to the lungs. CONCLUSION: Thus, the cumulative dose provocation regimen can induce a more pronounced Th2-like immune response in asthmatic patients than the low dose provocation model.

Adult↗
PubMed2001

Expression of interferon-alpha subtypes in peripheral mononuclear cells from patients with chronic hepatitis C: a role for interferon-alpha5.

Interferon (IFN)-alpha is a family of antiviral proteins encoded by different genes. The biological significance of the existence of various IFN-alpha subtypes is not clear. We have investigated the interferon system in chronic hepatitis C virus (HCV) infection, a disease that responds to interferon-alpha2 therapy in only a limited proportion of cases. We analysed the expression of interferon regulatory factor (IRF)-1, IRF-2, and IFN-alpha subtypes in nonstimulated and Sendai virus-stimulated peripheral blood mononuclear cells (PBMC) from HCV infected patients and healthy controls. We observed that the IRF-1 mRNA and IRF-1/IRF-2 ratios were increased in PBMC from hepatitis C patients with respect to normal subjects. Sendai virus stimulation of PBMC led to a significant increase in the levels of IRF-1, IRF-2 and IFN-alpha mRNAs and in the production of IFN-alpha protein with respect to basal values in healthy controls as well as in patients with HCV infection. In addition, we found that while natural HCV infection induced increased IFN-alpha5 expression in PBMC, in vitro infection of these cells with Sendai virus caused a raise in the expression of IFN-alpha8 in both patients and normal controls. In summary, our results indicate that virus-induced activation of the IFN system in human PBMC is associated with selective expression of individual IFN-alpha subtypes, IFN-alpha5 being the specific subtype induced in PBMC from patients with chronic HCV infection.

Adult↗
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

Adenovirus-mediated CD40 ligand gene therapy in a rat model of orthotopic hepatocellular carcinoma.

Unresectable hepatocellular carcinoma (HCC) lacks effective therapy and entails very poor prognosis. In this study, we have explored a gene-therapeutic approach to stimulate antitumor immunity by adenoviral-mediated transfer of CD40 ligand to treat HCC in rats. In vitro infection of a rat HCC cell line (McA-RH7777) with adenoviral vector expressing CD40 ligand (AdCMVmCD40L) induced CD40L expression in a dose-dependent manner. Expression of CD40L in McA-RH7777 cells did not alter their growth rate in vitro, but it abrogated their tumorigenicity when CD40L-expressing cells were implanted into the liver of syngenic Buffalo rats. In vivo gene therapy of established orthotopic HCC nodules (6.5 mm in diameter) in Buffalo rats by intratumor injection of AdCMVmCD40L vector led to complete tumor eradication and long-term survival in 69.5% of treated animals. Therapy with AdCMVmCD40L induced strong lymphocytic infiltration of the tumoral tissue and increased apoptosis of malignant cells. The observed antitumoral effect was mediated by CD8(+) T cells and was associated with increased interleukin (IL)-12 serum levels and enhanced natural killer (NK) activity. Animals that eliminated the tumor after in vivo gene therapy developed protective antitumor immunity being resistant to rechallenge with neoplastic cells. Toxicity of the therapy with AdCMVmCD40L was slight, with only a transient increase in the level of serum transaminases and minor lymphocyte infiltration of normal liver tissue. These data demonstrate that intratumoral administration of AdCMVmCD40L may provide an efficient and safe treatment for HCC.

Adenoviridae↗
PubMed2001

Nuclear factor-kappa B in the liver of patients with chronic hepatitis C: decreased RelA expression is associated with enhanced fibrosis progression.

The mechanisms of liver damage in chronic hepatitis C virus (HCV) infection are poorly understood. The transcription factor, nuclear factor-kappa B (NF-kappa B), regulates the expression of genes involved in apoptosis, inflammation, and antiviral response. It plays a protective role in several forms of liver damage. In this study, we analyzed NF-kappa B by gel mobility shift assay and immunohistochemistry in liver biopsies from HCV-infected patients, and we have determined the hepatic levels of the components of the NF-kappa B system by semiquantitative polymerase chain reaction (PCR). We found that NF-kappa B was activated in the liver of patients with chronic hepatitis C. Neither NF-kappa B activity nor the RNA levels of NF-kappa B subunits showed correlation with liver inflammatory activity, viral load, or HCV genotype. By contrast, hepatic mRNA values of RelA, the main element of active NF-kappa B, correlated inversely with apoptosis (r = -.68; P <.05) and with the rate of fibrosis progression (r = -.51; P <.04). In intermediate/rapid fibrosers, RelA mRNA levels were significantly decreased as compared with slow fibrosers (P <.003) and with normal livers (P <.03). In conclusion, we found that NF-kappa B is activated in chronic HCV-infected livers, and that the expression of RelA is inversely correlated with liver cell apoptosis and with the rate of fibrosis progression. Our data thus suggest that RelA expression may protect against liver fibrosis and hepatocellular damage.

Adult↗
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

Influence of the decrease in ciprofloxacin susceptibility and the presence of human serum on the in vitro susceptibility of Streptococcus pneumoniae to five new quinolones.

Sixty recent Streptococcus pneumoniae isolates with different susceptibilities to ciprofloxacin (14 with MIC 0.5 mg/L, 10 with MIC 1 mg/L, eight with MIC 2 mg/L, 11 with MIC 4 mg/L and 17 with MIC > or =8 mg/L) were tested against five new quinolones using Todd-Hewitt broth with and without 80% serum. The final inoculum was 5 x 10(5) cfu/mL. Gemifloxacin and clinafloxacin exhibited the lowest MIC90 values and resistance rates (percentage above and defined breakpoint) with and without serum for strains with a ciprofloxacin MIC of > or =4 mg/L. Other quinolones tested were less active against strains with reduced ciprofloxacin susceptibility. The presence of serum did not affect susceptibility to moxifloxacin, but increased the resistance rates to other new quinolones for strains with high ciprofloxacin MICs.

Anti-Infective Agents↗
PubMed2001

Streptococcus pneumoniae isolates with reduced susceptibility to ciprofloxacin in Spain: clonal diversity and appearance of ciprofloxacin-resistant epidemic clones.

Analysis of the pulsed-field gel electrophoretic profiles of 82 pneumococcal isolates with reduced susceptibility to ciprofloxacin (RSC) and of 90 co-occurring susceptible isolates indicates a considerable genetic diversity among isolates with RCS and points to a close relation between the two groups. This finding suggests that pneumococci with RCS emerge through independent mutational events.

Anti-Infective Agents↗
PubMed2001

Protection against woodchuck hepatitis virus (WHV) infection by gene gun coimmunization with WHV core and interleukin-12.

Woodchuck hepatitis virus (WHV) and hepatitis B virus (HBV) are closely similar with respect to genomic organization, host antiviral responses, and pathobiology of the infection. T-cell immunity against viral nucleocapsid (HBcAg or WHcAg) has been shown to play a critical role in viral clearance and protection against infection. Here we show that vaccination of healthy woodchucks by gene gun bombardment with a plasmid coding for WHcAg (pCw) stimulates proliferation of WHcAg-specific T cells but that these cells do not produce significant levels of gamma interferon (IFN-gamma) upon antigen stimulation. In addition, animals vaccinated with pCw alone were not protected against WHV inoculation. In order to induce a Th1 cytokine response, another group of woodchucks was immunized with pCw together with another plasmid coding for woodchuck interleukin-12 (IL-12). These animals exhibited WHcAg-specific T-cell proliferation with high IFN-gamma production and were protected against challenge with WHV, showing no viremia or low-level transient viremia after WHV inoculation. In conclusion, gene gun immunization with WHV core generates a non-Th1 type of response which does not protect against experimental infection. However, steering the immune response to a Th1 cytokine profile by IL-12 coadministration achieves protective immunity. These data demonstrate a crucial role of Th1 responses in the control of hepadnavirus replication and suggest new approaches to inducing protection against HBV infection.

Animals↗
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↗