Probable Association Between Oral Lichen Planus and presence of Helicobacter Pylori: a Preliminary Study in a Chilean Population / Probable Asociación entre Liquen plano Oral y la presencia de Helicobacter pylori: estudio Preliminar en Chile

ABSTRACT: Oral Lichen planus (OLP) is one of the main inflammatory diseases of the oral mucosa that is considered as a potentially malignant disorder. The exact pathogenesis of OLP remains to be completely understood. However, presence of bacteria has been associated to the inflammatory response observed in OLP. Particularly, Helicobacter pylori a major etiological agent of gastrointestinal inflammatory diseases and risk factor for gastric cancer, has been associated to Lichen planus. Here we studied a group of Chilean patients if there is any association between the presence of Helicobacter pylori and the clinical manifestation of OLP. We found a significant difference between the patients positive for H. pylori and the age of OLP diagnosis, suggesting that oral H. pylori might induce the disease at an earlier age. However, we could not confirm a statistically significance between the presence of the bacteria and OLP.

RESUMEN: Liquen Plano Oral (LPO) es una enfermedad inflamatoria de la mucosa oral considerada como desorden potencialmente maligno. La patogénesis exacta de LPO es desconocida. Sin embargo, se ha asociado la presencia de bacterias como responsables de la inflamación observada en LPO. Particularmente, Helicobacter pylori (H. pylori), agente etiológico principal de enfermedades inflamatorias gastrointestinales y factor de riesgo de cáncer gástrico, ha sido asociado con LPO. Se estudió la posible asociación entre H. pylori y manifestaciones clínicas de LPO en un grupo de pacientes Chilenos. Se encontró diferencia significativa entre los pacientes positivos para H. pylori y la edad de diagnóstico de LPO, sugiriendo que H. pylori podría inducir la enfermedad a temprana edad. Sin embargo, no se pudo confirmar significancia estadística entre la presencia de esta bacteria y la presencia de displasia en LPO.

Infection and invasion mechanisms of Trypanosoma cruzi in the congenital transmission of Chagas' disease: A proposal

Chagas' disease is produced by the haemophlagelated protozoan Trypanosoma cruzi and transmitted by haematophages insects such as Triatoma infestans (vinchuca). Due to vector control, congenital transmission gains importance and is responsible for the presence and expansion of this disease in non-endemic areas. The mechanisms of congenital infection are uncertain. It has been suggested that the parasite reaches the fetus through the bloodstream by crossing the placental barrier, and that congenital Chagas' disease is the result of complex interactions between the immune response, placental factors, and the parasite's characteristics. We review the cellular and molecular mechanisms of infection and invasion of the parasite and how immune and placental factors may modulate this process. Finally, we propose a possible model for the vertical transmission of Chagas' disease.

Chagas disease: Present status of pathogenic mechanisms and chemotherapy

There are approximately 7.8 million people in Latin America, including Chile, who suffer from Chagas disease and another 28 million who are at risk of contracting it. Chagas is caused by the flagellate protozoan Trypanosoma cruzi. It is a chronic disease, where 20 percent-30 percent of infected individuals develop severe cardiopathy, with heart failure and potentially fatal arrhythmias. Currently, Chagas disease treatment is more effective in the acute phase, but does not always produce complete parasite eradication during indeterminate and chronic phases. At present, only nifurtimox or benznidazole have been proven to be superior to new drugs being tested. Therefore, it is necessary to find alternative approaches to treatment of chronic Chagas. The current treatment may be rendered more effective by increasing the activity of anti-Chagasic drugs or by modifying the host's immune response. We have previously shown that glutathione synthesis inhibition increases nifurtimox and benznidazole activity. In addition, there is increasing evidence that cyclooxygenase inhibitors present an important effect on T. cruzi infection. Therefore, we found that aspirin reduced the intracellular infection in RAW 264.7 cells and, decreased myocarditis extension and mortality rates in mice. However, the long-term benefit of prostaglandin inhibition for Chagasic patients is still unknown.

Signal transduction and gene expression regulated by calcium release from internal stores in excitable cells

Calcium regulation of several transcription factors involves different calcium-dependent signaling cascades and engages cytoplasmic as well as nuclear calcium signals. The study of the specific sources of calcium signals involved in regulation of gene expression in skeletal muscle has been addressed only recently. In this tissue, most cytoplasmic and nuclear calcium signals originate from calcium release from internal stores, mediated either by ryanodine receptor (RyR) or IP3 receptor (IP3R) channels. The latter are located both in the sarcoplasmic reticulum (SR) and in the nuclear membrane, and their activation results in long-lasting nuclear calcium increase. The calcium signals mediated by RyR and IP3R are very different in kinetics, amplitude and subcellular localization; an open question is whether these differences are differentially sensed by transcription factors. In neurons, it is well established that calcium entry through L-type calcium channels and NMDA receptors plays a role in the regulation of gene expression. Increasing evidence, however, points to a role for calcium release from intracellular stores in this process. In this article, we discuss how RyR-mediated calcium release contributes to the activation of the calcium-dependent transcription factor CREB and the subsequent LTP generation. We present novel results from our laboratory showing ERK-mediated CREB activation by hydrogen peroxide. This activation takes place in the absence of extracellular calcium and is blocked by inhibitory ryanodine concentrations, suggesting it is caused by redox activation of RyR-mediated calcium release.