Operatoria dental y endodoncia 1: la degradación de la interfaz resina-dentina favorece la filtración bacteriana / Operative dentistry and endodontics 1: the interface resin-dentin degradation allows for the bacterial microleakage

La integridad y la estabilidad de la interfase adhesivo/dentina en las restauraciones realizadas mediante resinas compuestas se encuentra constantemente comprometida por la hidrólisis progresiva de sus componentes hidrofílicos y la degradación de la matriz colágena, producida por la reactivación de una serie de endopeptidasas denominadas metaloproteinasas (MMP) y otras enzimas colagenolíticas que se encuentran fosilizadas en la matriz de la dentina. Esto lleva a la destrucción de la capa híbrida y facilita la penetración bacteriana en la interfase, el aumento de la hipersensibilidad posoperatoria y la formación de caries recurrentes. Estos problemas inciden además en la pérdida de retención de la restauración y se constituyen en el principal factor etiológico de los procesos inflamatorios que comprometen seriamente la salud de la pulpa dental. Debido a que la integridad de la matriz colágena es esencial para preservar la durabilidad de la adhesión de las restauraciones, se han intentado algunas estrategias, con el objeto de inhibir o al menos reducir en lo posible la acción de las enzimas colagenolíticas sobre la estabilidad de la interfase. A pesar de que algunas de las estrategias ensayadas hasta el momento han demostrado ser eficaces, aún se encuentran en una etapa netamente experimental y requieren ser más profundamente investigadas

Rol de las metaloproteinasas y sus inhibidores en patología tumoral / Role of metalloproteinases and their inhibitors in tumors

Las metaloproteinasas (MMPs) intervienen en diversos procesos fisiológicos y patológicos del organismo. Regulan, por ejemplo, las vías de señalización que controlan el crecimiento celular, la inflamación y la angiogénesis. Cumplen funciones moduladoras en el complejo microambiente tumoral interviniendo en las etapas tempranas de la carcinogénesis, en la invasión y la producción de metástasis tumorales. Participan en el procesamiento de moléculas bioactivas como citoquinas, quemoquinas y factores de crecimiento. Las MMPs tienen como substrato a las proteínas de la matriz extracelular (MEC) y su actividad es regulada por inhibidores endógenos (TIMPs). El adecuado balance entre ambas moléculas es fundamental para mantener la homeostasis. Debido al papel que desempeñan en diferentes etapas de la biología del cáncer, son un blanco potencial para futuras estrategias en la terapéutica de esta enfermedad.

Metalloproteinases (MMPs) are involved in different physiological and pathological processes. They regulate several signaling pathways in cell growth, inflammation and angiogenesis. The MMPs modulate the complex tumor microenvironment and are involved in the early stages of carcinogenesis, tumor invasion and metastasic processes. MMPs participate in the processing of bioactive molecules such as cytokines, chemokines and growth factors. Their substrates are the extracellular matrix proteins and endogenous inhibitors (TIMPs) regulate their functions. The accurate balance between these two molecules, MMPs and TIMPs, is critical for maintaining homeostasis. Due to their role in cancer biology, MMPs are potential targets for fu ture therapeutic strategies of this malignant disease.

Perfil de expressão das metaloproteinases de matriz (MMPs) e seus inibidores (TIMP e RECK) em tumores odontogênicos benignos / Expression profile of matrix metalloproteinases (MMPs) and their inhibitors (TIMP and RECK) in odontogenic tumors benign

Os tumores odontogênicos benignos compreendem um grupo de neoplasias originárias dos tecidos dentários. Pesquisas vêm buscando identificar moléculas envolvidas nos mecanismos moleculares que regulam a remodelação da matriz extracelular (MEC) e como isto influencia no comportamento localmente invasivo presente em alguns destes tumores. A Transição Epitélio-Mesenquimal (TEM conversão do fenótipo epitelial em mesenquimal) é bem caracterizada em diversos carcinomas, culminando em mestástase. MMPs são enzimas que degradam os componentes da MEC, geram moléculas bioativas, participam da TEM e o controle da remodelação da MEC dá-se pelo balanço entre elas, seus inibidores (TIMPs e RECK) e seu ativador (EMMPRIN). Assim, o objetivo deste trabalho foi delinear o perfil de expressão das MMPs (-2, -7, -9 e -14), seus inibidores (TIMPs -2, -3, -4 e RECK), seu ativador (EMMPRIN) e marcadores da TEM (Snail, Slug, N-caderina, Fibronectina, a-Actina de músculo liso e Vimentina) em Ameloblastomas (AB) e Tumores Odontogênicos Cístico Calcificantes (TOCC). Ainda, realizamos a comparação da expressão de cada molécula avaliada em cada compartimento celular (epitélio e estroma) e correlação entre as moléculas avaliadas no mesmo tumor. Utilizamos 19 casos de AB e 18 casos de TOCC (Serviço de Anatomia Patológica da FOUSP), localização das enzimas/proteínas por imunoistoquímica e analisadas nos compartimentos epitelial e estromal

Todas as proteínas/enzimas analisadas foram detectadas tanto nos AB quanto nos TOCC, sendo a maioria expressa em ambos os compartimentos. A N-caderina foi localizada apenas no epitélio dos AB e a Vimentina somente no estroma em ambos os tumores. Na comparação entre o epitélio x estroma dos ameloblastomas, verificamos que houve diferença estatisticamente significante (p<0,05) para a MMP-2, MMP-7, EMMPRIN/CD147, Fibronectina, a-Actina de músculo liso, N-caderina, Vimentina, Snail e Slug. Na comparação entre o epitélio x estroma dos TOCC, verificamos que houve diferença estatisticamente significante (p<0,05) para a MMP-9, RECK, EMMPRIN/CD147, Vimentina, N-caderina, Snail e Slug. Assim, entre o epitélio x estroma dos ameloblastomas e TOCC, verificamos que houve diferença estatisticamente significante (p<0,05) para a MMP-2, MMP-7, MMP-9, RECK, EMMPRIN/CD147, Fibronectina, Vimentina, a-Actina de músculo liso, N-caderina, Snail e Slug. Esta é a primeira vez que a EMMPRIN, RECK, TIMP-3, TIMP-4, Ncaderina, Snail e Slug são descritas em TOCC e TIMP-3, TIMP-4, Snail e Slug em ameloblastomas. Concluímos que estas proteínas/enzimas estão diferencialmente expressas tanto no epitélio quanto no estroma destes tumores e sugerimos que estes podem participar do comportamento localmente invasivo.

Odontogenic tumors comprise a group of benign neoplasms originating from dental tissues. Research looking for identify molecules involved in the molecular mechanisms that regulate extracellular matrix remodeling (ECM) and how this impacts on locally invasive behavior present in some of these tumors. Epithelial-Mesenchymal Transition (EMT - conversion of epithelial phenotype into mesenchymal phenotype) is well characterized in several carcinomas, leaving to metastasis. MMPs are enzymes that degrade ECM components, generate bioactive molecules, participating in the EMT and control ECM remodeling is given by the balance between them, their inhibitors (TIMPs and RECK) and its activator (EMMPRIN). The aim of this study was evaluate expression profile of MMPs (-2, -7, -9 and - 14), their inhibitors (TIMPs -2, -3, -4 and RECK), its activator (EMMPRIN) and EMT markers (Snail, Slug, N-cadherin, Fibronectin, -smooth muscle actin and Vimentin) in ameloblastomas (AB) and Calcifying Cystic Odontogenic Tumor (CCOT). We also compared the expression of each molecule assessed in each cellular compartment (epithelium and stroma) and correlation between molecules evaluated in the same tumor. We used 19 AB cases and 18 CCOT cases from files of Pathology Laboratory (FOUSP), localization of enzymes/proteins and analyzed by immunohistochemistry in epithelial and stromal compartments

All proteins/enzymes were detected in both AB and CCOT, mostly expressed in both compartments. N-cadherin was localized only in the epithelium of AB and Vimentin only in stromal in both tumors. Comparing "epithelium vs stroma" of AB, we observed a statistically significant difference (p <0.05) for MMP-2, MMP-7, EMMPRIN/CD147, Fibronectin, -smooth muscle actin, N-cadherin, Vimentin, Snail and Slug. Comparing "epithelium vs stroma" of CCOT, we observed a statistically significant difference (p <0.05) for MMP-9, RECK, EMMPRIN/CD147, Vimentin, N-cadherin, Snail and Slug. Analizing epithelium vs stroma" between AB and CCOT, we observed a statistically significant difference (p <0.05) for MMP-2, MMP-7, MMP-9, RECK, EMMPRIN/CD147, Fibronectin, Vimentin , -smooth muscle actin, N-cadherin, Snail and Slug. This is the first time that EMMPRIN, RECK, TIMP-3, TIMP-4, N-cadherin, Snail and Slug are described in CCOT and TIMP-3, TIMP-4, Snail and Slug in AB. We conclude that these proteins/enzymes are differentially expressed in both epithelium and stroma of these tumors and suggest that they may participate locally invasive behavior.

Estrés oxidativo e inflamación en insuficiencia cardiaca: Mecanismos de daño y alternativas terapéuticas / Oxidative stress and inflammation in heart failure: Mechanisms of damage and therapeutic alternatives

Despite advances in treatment, chronic heart failure still is associated with a poor prognosis and remains a leading cause of cardiovascular death. Cumulating evidence suggests that imbalances in redox state lead to a higher generation of reactive oxygen species. This phenomenon, along with pro-inflammatory cytokine activation and extra cellular matrix alterations with reactive fibrosis, play an important role in the pathogenesis and progression of heart failure, through the development of endothelial and myocardial dysfunction. The understanding of the underlying phenomena and the metabolic pathways involved will allow further development of therapies aiming to change the natural history of heart failure.

Microglia, major player in the brain inflammation: their roles in the pathogenesis of Parkinson's disease

Inflammation, a self-defensive reaction against various pathogenic stimuli, may become harmful self-damaging process. Increasing evidence has linked chronic inflammation to a number of neurodegenerative disorders including Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis. In the central nervous system, microglia, the resident innate immune cells play major role in the inflammatory process. Although they form the first line of defense for the neural parenchyma, uncontrolled activation of microglia may directly toxic to neurons by releasing various substances such as inflammatory cytokines (IL-1beta, TNF-alpha, IL-6), NO, PGE

Las metaloproteinasas en la remodelación de la pared vascular / The metalloproteinases in the vascular wall remodelling

Metalloproteinases (MTP) are enzymes that degrade the extracellular matrix, mainly collagen tissue. Normally these enzymes are expressed in vascular walls as proenzyme together with inhibitors of the active enzymes. By effect of different citokines, produced by an inflammatory process in the vascular wall, these proenzymes are activated to an extent that surprasses the action of the inhibitors and degrade collagen. This action may partly explain the rupture of atherosclerosis plaques (vulnerability) and also the remodelling of the vessel wall with compensatory enlargement of the vessel (increase in the outer size of the vessel) that allows the plaques to develop inside the arterial wall without protruding into the vessel lumen for many years. The occlusion of safenous vein in aortocoronary bypass grafts is due to fibromuscular proliferation and atheroma development and therefore the participation of MTP in the occlusion of these vessels is a reasonable hypothesis. However, the structural features of safenous vein bypass grafts are different from those of atheroma in native coronary arteries. Mainly the compensatory enlargement of the vessels does not occur because of intense fibrous tissue development including the adventitia and therefore the new tissue in the wall is forced to protrude into the vessel lumen. The reason for this difference in the vessel wall remodeling is not clear and the article by Grez et al in this issue of this journal is an starting and promising study in the regard

Actividades hemorrágicas y coagulante del veneno de Bothrops alternatus de Argentina / Haemorrhagic and clotting activities of Argentina B. alternatus venon

Se trabajó con veneno crudo de Bothrops alternatus para determinar sus actividades hemorrágica y coagulante. Para hallar la actividad hemorrágica se inocularon ratones, en forma intradérmica, con diluciones seriadas de veneno, en un volumen de 0,1 ml de solución salina amortiguada con fosfato, pH 7,2. Luego de 2 horas, se sacrificaron con éter y se midió el área hemorrágica. La Dosis Hemorrágica Mínima (DHM) es la cantidad de veneno que produce un área hemorrágica mínima de 10 mm de diámetro, para el veneno de B. alternatus fue de 3,6 µg. El estudio de la Dosis Coagulante Mínima (DCM) se realizó confrontando diluciones seriadas de veneno con plasma humano. La DMC, capaz de coagular el plasma humano en 60 seg, fue de 14,5 µg/ml. Al igual que otras especies del género Bothrops de Latinoamérica, el veneno de B. alternatus de Argentina posee marcada actividad hemorrágica y coagulante

Transición de la forma enzimática latente a activa como un modelo de regulación de la degradación de matriz extracelular en el corioamnios durante el trabajo de parto humano / Transition from the laten to active enzymatic form asa regulation model for the degradation of choriomniotic extracelular matrix during human labor

Las metaloprotesas de matriz extracelular (MMP) son las mediadoras fisiológicas de la degradación de la colágena y su participación en la fisiopatogenia de la ruptura prematura de membranas ha sido sugerida por nuestro grupo. Con objeto de definir si algunas MMP se activan de manera coordinada con el trabajo de parto en las membranas fetales, analizamos la actividad enzimática y proteína inmunorreactiva presente en extractos de membranas obtenidas durante cesáreas, sin trabajo de parto, aunque su actividad/cantidad fue apenas detectable. En cambio los extractos de membranas fetales obtenidas durante el trabajo de parto activo, mostraron gran actividad/cantidad de ésta MMP. Con ayuda de un anticuerpo monoclonal, fue posible demostrar que la forma activa de la MMP-9 se podía encontrar sólo en las muestras con trabajo de parto. La MMP-9 y su ARN mensajero correspondiente fueron localizados por inmunohistoquímica e hibridación in situ en el epitelio amniótico, en algunos fibroblastos de la capa compacta y en células con características de trofoblasto en el corion. Se concluye que: 1. La actividad y la cantidad de la MMP-9 se incrementa de manera selectiva asociada al trabajo de parto y 2. que esta enzima es expresada por diferentes poblaciones celulares de la membrana fetal

Secretion of gelatinases by human pancreatic cancer cell lines: lack of correlation with invasive ability

Se estudiaron doce líneas celulares inmortalizadas humanas derivadas de tumores primarios o metástasis de carcinomas pancreáticos, con respecto a su invasividad in vitro. Se hallaron distintos niveles de capacidad invasiva y respuestas quimiotácticas. Con el objeto de determinar el rol de las metaloproteinasas en la invasión del cáncer pancreático, se realizaron zimogramas de medios condicionados de las células. No se hallaron, sin embargo, correlaciones entre la capacidad invasiva y la secreción de gelatinasas en las líneas de carcinomas pancreáticos. Se discuten las posibles causas de los resultados hallados

Regulation of extracellular matrix-degrading proteases

Extracellular matrix-degrading enzymes have a very important role in many normal and pathological processes. Members of the matrix metalloproteinase and plasminogen activator families are the major modulators of extracellular matrix degradation. Here, we discuss some topics about these enzymes giving special attention to the transcriptional and extracellular regulation of their expression.

The metalloproteinase of Leishmania: leishmanolysin

Zinc metalloproteinases are a diverse group of endo- and exoproteinases related only by their common catalytic mechanism and similar primary structure defining the metal binding domain. They are involved in tissue remodelling, metastasis, peptide hormone processing and digestion. Outside of the zinc binding site, their primary structures are highly divergent, suggesting that this group of enzymes is the product of convergent evolution. The three dimensional structures of small soluble bacterial (thermolysin) and eukaryote (astacin) metalloproteinases has allowed the establishment of several families of metalloproteinases based upon the zinc binding ligands of the enzymes. Thus far, no high-molecular weight membrane bound metalloproteinase has been crystallised; unfortunately these are among the most interesting in terms of human physiology. Leishmanolysin, the abundant surface metalloproteinase of several genera of kinetoplastid protozoans, most notably Leishmania, provides an abundant source of glycophosphatidylinositol-anchored glycoprotein for biochemical and structural studies, which will not only lead to a better understanding of the role of the proteinase in the life cycle of the protozoan, but will also provide a framework upon which to model the structures of mammalian metalloproteinases.