Francisco Javier Gálvez-Gastélum

Molecular aspects of hepatic encephalopathy

INTRODUCTION Liver fibrosis and its end stage, cirrhosis, is an enormous worldwide health problem. Hepatic encephalopathy (HE) or portal-systemic encephalopathy continues to be a major clinical problem of long-term cirrhosis. In this review we emphasise the molecular basis of HE and the involvement of oxidative stress in the development of this disease. BACKGROUND Several studies suggest that the pathogenesis of HE could be multifactorial and have implicated different factors, such as alterations in blood brain barrier, substances; such as ammonia and manganese, neurotransmission disorders such as dopamine, glutamate and GABA. DEVELOPMENT HE is a severe complication of both acute and chronic liver failure. Neuropathologically, it is characterized by astrocyte changes known as Alzheimer type II astrocytosis. In addition, astrocytes manifest altered expression of astrocyte-specific proteins, such as, glial fibrillary acidic protein, glutamine synthetase, monoamine oxidase and peripheral type benzodiazepine receptors. CONCLUSIONS HE is a complex neuropsychiatric syndrome associated with liver failure. These alterations are products of increases in oxidative stress in brain due to neurotoxin activity. The main strategy for HE treatment is directed at ammonia reduction, which can be achieved either by decreasing its absorption/production or increasing its removal.

Isosorbide Dinitrate Spray as Therapeutic Strategy for Treatment of Chronic Venous Ulcers

Venous ulcers are the most common form of leg ulcers, which induce lesion because of the loss of substances deposited on the damaged skin. Isosorbide dinitrate is a vasodilator with effects on both arteries and veins and induces opening of vascular layers. The objective is to study the effects of isosorbide dinitrate-spray in patients with chronic venous ulcers. Forty-five patients of both sexes with chronic venous ulcers were randomized to receive isosorbide dinitrate or placebo sprays daily for 3 months. The ulcers were measured and clinical characteristics were taken every 15 days during the treatment. Patients treated with isosorbide dinitrate showed an improvement of the ulcerated area (71.29%) compared with patients treated with placebo (54.35%). The histopathological study indicated an increment in the number of hypertrophic and hyperplasic capillaries. Macroscopically, the isosorbide dinitrate-treatment showed the best results, but it was only during the first 6 weeks of treatment. Patients with chronic venous ulcer receiving isosorbide dinitrate spray showed improvement.

El factor de crecimiento transformante beta como blanco terapéutico

El factor de crecimiento transformante beta (TGF-beta) es una familia de proteinas que incluye al TGF-beta, activinas y a la proteina morfogenica de hueso (BMP, por sus siglas en ingles), citocinas que son secretadas y se relacionan estructuralmente en diferentes especies de metazoarios. Los miembros de la familia del TGF-beta regulan diferentes funciones celulares como proliferacion, apoptosis, diferenciacion, migracion, y tienen un papel clave en el desarrollo del organismo. El TGF-beta esta implicado en varias patologias humanas, incluyendo desordenes autoinmunes y vasculares, asi como enfermedades fibroticas y cancer. La activacion del receptor del TGF-beta propicia su fosforilacion en residuos de serina/treonina y dispara la fosforilacion de proteinas efectoras intracelulares (smad), que una vez activas se translocan al nucleo para inducir la transcripcion de genes blanco, y asi regular procesos y funciones celulares. Se estan desarrollando novedosas estrategias terapeuticas encaminadas a corregir las alteraciones presentes en patologias que involucran al TGF-beta como actor principal.

Natural polymorphisms and unusual mutations in HIV-1 protease with potential antiretroviral resistance: a bioinformatic analysis

BackgroundThe correlations of genotypic and phenotypic tests with treatment, clinical history and the significance of mutations in viruses of HIV-infected patients are used to establish resistance mutations to protease inhibitors (PIs). Emerging mutations in human immunodeficiency virus type 1 (HIV-1) protease confer resistance to PIs by inducing structural changes at the ligand interaction site. The aim of this study was to establish an in silico structural relationship between natural HIV-1 polymorphisms and unusual HIV-1 mutations that confer resistance to PIs.ResultsProtease sequences isolated from 151 Mexican HIV-1 patients that were naïve to, or subjected to antiretroviral therapy, were examined. We identified 41 unrelated resistance mutations with a prevalence greater than 1%. Among these mutations, nine exhibited positive selection, three were natural polymorphisms (L63S/V/H) in a codon associated with drug resistance, and six were unusual mutations (L5F, D29V, L63R/G, P79L and T91V). The D29V mutation, with a prevalence of 1.32% in the studied population, was only found in patients treated with antiretroviral drugs. Using in silico modelling, we observed that D29V formed unstable protease complexes when were docked with lopinavir, saquinavir, darunavir, tipranavir, indinavir and atazanavir.ConclusionsThe structural correlation of natural polymorphisms and unusual mutations with drug resistance is useful for the identification of HIV-1 variants with potential resistance to PIs. The D29V mutation likely confers a selection advantage in viruses; however, in silico, presence of this mutation results in unstable enzyme/PI complexes, that possibly induce resistance to PIs.

The Synthetic Cathelicidin HHC-10 Inhibits Mycobacterium bovis BCG In Vitro and in C57BL/6 Mice

Tuberculosis causes close to 1.5 million deaths in the world, with new cases exceeding 9 million in recent years. Coinfection with HIV further worsens the global situation. New molecules that overcome the limitations of currently used drugs are needed. We aimed to determine whether HHC-10 is active against the Mycobacterium tuberculosis complex bacteria Mycobacterium bovis bacille calmette guerin (BCG) in vitro and in vivo. For this, HHC-10 was tested in vitro using different peptide concentrations, and in vivo, in C57BL/6 mice infected intratracheally, at two doses (1.25 and 2.5 mg kg(-1), once a week, 4 weeks). Interferon (IFN)-γ, TNF-α, interleukin (IL)-4, and IL-10 mRNA transcript levels were compared between treated and nontreated mice. In vitro, HHC-10 decreased 69% and 88% the number of colony-forming units (CFU) per millileter recovered after 24-hr treatment at 50 and 100 μg/ml, respectively. In vivo, BCG CFUs in mouse lungs were reduced 77.8% and 95.8% at 1.25 and 2.5 mg kg(-1), respectively. IFN-γ expression was lower in the HHC-10-treated group than that of nontreated animals. Considering genomic conservation between BCG and M. tuberculosis, the in vitro and in vivo activities of HHC-10 observed in this study suggest that the use of this peptide may be useful as therapeutic agent against tuberculosis.

Combinatorial gene therapy renders increased survival in cirrhotic rats

BackgroundLiver fibrosis ranks as the second cause of death in Méxicos productive-age population. This pathology is characterized by acummulation of fibrillar proteins in hepatic parenchyma causing synthetic and metabolic disfunction. Remotion of excessive fibrous proteins might result in benefit for subjects increasing survival index. The goal of this work was to find whether the already known therapeutical effect of human urokinase Plasminogen Activator and human Matrix Metalloprotease 8 extends survival index in cirrhotic animals.MethodsWistar rats (80 g) underwent chronic intoxication with CCl4: mineral oil for 8 weeks. Cirrhotic animals were injected with a combined dose of Ad-delta-huPA plus Ad-MMP8 (3 × 1011 and 1.5 × 1011 vp/Kg, respectively) or with Ad-beta-Gal (4.5 × 1011) and were killed after 2, 4, 6, 8 and 10 days. Then, liver and serum were collected. An additional set of cirrhotic animals injected with combined gene therapy was also monitored for their probability of survival.ResultsOnly the cirrhotic animals treated with therapeutical genes (Ad-delta-huPA+Ad-MMP-8) showed improvement in liver fibrosis. These results correlated with hydroxyproline determinations. A significant decrement in alpha-SMA and TGF-beta1 gene expression was also observed. Cirrhotic rats treated with Ad-delta-huPA plus Ad-MMP8 had a higher probability of survival at 60 days with respect to Ad-beta-Gal-injected animals.ConclusionA single administration of Ad-delta-huPA plus Ad-MMP-8 is efficient to induce fibrosis regression and increase survival in experimental liver fibrosis.

Skin wound healing with chitosan thin films containing supported silver nanospheres

Dermal wound healing involves complex histo-molecular events aimed to repair the discontinuity of the epithelium. Employing nanometric silver particles provides an efficient antimicrobial effect for several dermal infections. The aim is to elucidate imminent advantages of silver nanoparticles, such as the possibility of modulating the epithelial cell repair process. Through the nanostructural implementation of chitosan thin films supporting silver nanoparticles, it was feasible to evaluate in vivo the efficacy and evolution of dermal recuperation after surgical damage. The characterization of chitosan silver nanoparticle films was performed by UV–visible spectra and Fourier transform infrared spectroscopy, X-ray diffraction, and high-resolution electron microscopy. An important dermal healing was accomplished in animals that were treated with chitosan films supporting silver nanoparticles, as confirmed by a histopathological analysis of the skin after 12 days of treatment. The developed chitosan thin film supporting an optimized amount of silver nanoparticles could be employed to treat diseases related to wound healing.