Carbonic Anhydrase Activators for Neurodegeneration: An Overview

Carbonic anhydrases (CAs) are a family of ubiquitous metal enzymes catalyzing the reversible conversion of CO2 and H2O to HCO3- with the release of a proton. They play an important role in pH regulation and in the balance of body fluids and are involved in several functions such as homeostasis regulation and cellular respiration. For these reasons, they have been studied as targets for the development of agents for treating several pathologies. CA inhibitors have been used in therapy for a long time, especially as diuretics and for the treatment of glaucoma, and are being investigated for application in other pathologies including obesity, cancer, and epilepsy. On the contrary, CAs activators are still poorly studied. They are proposed to act as additional (other than histidine) proton shuttles in the rate-limiting step of the CA catalytic cycle, which is the generation of the active hydroxylated enzyme. Recent studies highlight the involvement of CAs activation in brain processes essential for the transmission of neuronal signals, suggesting CAs activation might represent a potential therapeutic approach for the treatment of Alzheimer's disease and other conditions characterized by memory impairment and cognitive problems. Actually, some compounds able to activate CAs have been identified and proposed to potentially resolve problems related to neurodegeneration. This review reports on the primary literature regarding the potential of CA activators for treating neurodegeneration-related diseases

NANOSTRUCTURED MATERIALS: A NEW APPROACH TO DESIGN INNOVATIVE SCAFFOLDS FOR THE TREATMENT OF BONE DEFECTS

ntroduction The wide bone defects, caused by trauma, tumor, infectious, periprosthetic osteolysis, need to be surgically treated because their low potential of repair. Nowadays the bone allograft and autograft represent 80% of all transplantation done in the world. However this technique shows many disadvantages, such as the risk of infections, the immunological rejection, the low bone availability and the high costs. These reasons have motivated extensive research to find alternative strategies. As shown in literature, the future strategies are based on the synergic combination of different methodologies: use of biomimetic scaffold in order to support bone regeneration, use of mesenchymal stromal cells (MSCs) and growth factors. Successful regeneration necessitates the development of tissue-inducing scaffolds that mimic the hierarchical architecture of native tissue extracellular matrix (ECM). Cells in nature recognise and interact with the surface topography they are exposed to via ECM proteins. Here we are going to show the guidelines recently published for the design and development of nanostructured scaffolds for the bone regeneration, and the morphofunctional changing of MSCs interacting with nanogratings. Methods Aim of this study is to design, develop and preclinical test PET nanostructured scaffolds for the transplantation and differentiation of MSCs in the treatment of bone defects. The first step of our study was the extraction of patient's bone marrow and the isolation of MSCs. After characterizing (demonstrating the typical cell surface markers) and isolating the MSCs were cultivated on the PET substrates. The PET nanosubstrates were obtained by a low temperature embossing lithography (HEL) achieving low-damage nanotopographic surface modifications. After MSC cultivation on PET substrates we made a cytotoxicity evaluation, an optic and confocal microscopic evaluation (cells adhesion, cells polarization…) and tests to optimise cell differentiation towards osteogenic fate. Results PET is a highly suitable thermo-plastic material, able to sustain the necessary methods to obtain nanostructured substrates. MSCs cultivated on nanostructured PET rapidly align with the direction of the nanostructure itself without any cytotoxic effects. After the cultivation on the nanostructures, MSCs sustained cytoskeleton changes suggesting the activation of intracellular signaling (mechanotrasduction) promoting osteogenesis. Discussion The mechanisms by which nanotopographic cues influence stem cell proliferation and differentiation appear to involve changes in cytoskeletal organization and structure, potentially in response to the geometry and size of the underlying features of the ECM by a process called mechanotrasduction. The interaction of cells with nanotopographical features such as pores, ridges, groves, fibers, nodes, and their combinations has proven to be an important signaling modality in controlling cellular processes. Integrating nanotopographical cues is especially important in engineering complex tissues that have multiple cell types and require precisely defined cell-cell and cell-matrix interactions at the nanoscale. Thus, in the next-generation regenerative engineering approaches, nanoscale materials/scaffolds are expected to play a parimary role in controlling MSC fate and the consequent regenerative capacity. We believe that the continuous development of nanotechnology and deeply comprehension of how mechanical inputs can affect cell biology is fundamental to design the future scaffold for orthopedic applicatio

Comparative anti-inflammatory activities of antagonists to C3a and C5a receptors in a rat model of intestinal ischaemia/reperfusion injury

1. Complement activation is implicated in the pathogenesis of intestinal ischaemia–reperfusion injury (I/R), although the relative importance of individual complement components is unclear. A C3a receptor antagonist N(2)-[(2,2-diphenylethoxy)acetyl]-L-arginine (C3aRA) has been compared with a C5a receptor antagonist (C5aRA), AcF-[OPdChaWR], in a rat model of intestinal I/R. 2. C3aRA (IC(50)=0.15 μM) and C5aRA (IC(50)=0.32 μM) bound selectively to human polymorphonuclear leukocyte (PMN) C3a and C5a receptors, respectively. Effects on circulating neutrophils and blood pressure in the rat were also assessed. 3. Anaesthetised rats, subjected to intestinal ischaemia (30 min) and reperfusion (120 min), were administered intravenously with either (A) the C3aRA (0.1–1.0 mg kg(−1)); the C5aRA (1.0 mg kg(−1)); the C3aRA+C5aRA (each 1.0 mg kg(−1)); or vehicle, 45 min prior, or (B) the C3aRA (1.0 mg kg(−1)) or vehicle, 120 min prior to reperfusion. 4. The C3aRA and C5aRA, administered 45 min prior to reperfusion, displayed similar efficacies at ameliorating several disease markers (increased oedema, elevated ALT levels and mucosal damage) of rat intestinal I/R. The combination drug treatment did not result in greater injury reduction than either antagonist alone. However, doses of the C3aRA (0.01–10 mg kg(−1)) caused transient neutropaenia, and the highest dose (10 mg kg(−1)) also caused a rapid and transient hypertension. 5. The C3aRA (1.0 mg kg(−1)), delivered 120 min prior to reperfusion to remove the global effect of C3aRA-induced neutrophil sequestration, did not attenuate the markers of intestinal I/R, despite persistent C3aR antagonism at this time. 6. C3aR antagonism does not appear to be responsible for the anti-inflammatory actions of this C3aRA in intestinal I/R in the rat. Instead, C3aRA-mediated global neutrophil tissue sequestration during ischaemia and early reperfusion may account for the protective effects observed

Comparative protection against rat intestinal reperfusion injury by a new inhibitor of sPLA(2), COX-1 and COX-2 selective inhibitors, and an LTC(4) receptor antagonist

1. A new group IIa sPLA(2) inhibitor was compared with selective inhibitors of COX-1, COX-2 and an LTC(4) antagonist for effects on local and remote tissue injuries following ischaemia and reperfusion (I/R) of the small intestine in rats. 2. In an acute model of ischaemia (30 min) and reperfusion (150 min) injury in the absence of inhibitors, there was significant intestinal haemorrhage, oedema and mucosal damage, neutropenia, elevated serum levels of aspartate aminotransferase (AST) and hypotension. 3. Preischaemic treatment with the inhibitor of sPLA(2) (Group IIa), at 5 mg kg(−1) i.v. or 10 mg kg(−1) p.o. significantly inhibited I/R-induced neutropenia, the elevation of serum levels of AST, intestinal oedema and hypotension. 4. Pretreatment with the COX-2 inhibitor celebrex (10 mg kg(−1) i.v.) and the LTC(4) antagonist zafirlukast (1 mg kg(−1) i.v.) also showed marked improvement with I/R-induced AST, oedema and neutropenia. Hypotension was only reduced by the LTC(4) antagonist. The COX-1 inhibitor flunixin (1 mg kg(−1) i.v.) did not effect improvement in the markers of tissue injury. 5. Histological examination of rat I/R injury showed that all of the drugs offered some protection to the mucosal layer damage compared to no drug treatment. Given i.v., the sPLA(2) inhibitor was more effective than either the COX-1 or COX-2 inhibitors in preventing rat I/R injury. 6. These results indicate that a potent new inhibitor of sPLA(2) (group IIa) protects the rat small intestine from I/R injury after oral or intravenous administration. COX-2 and LTC(4) inhibitors also showed some beneficial effects against intestinal I/R injury. Our study suggests that sPLA(2) (Group IIa) may have a pathogenic role in intestinal I/R in rats

Controle de danos: uma opção tática no tratamento dos traumatizados com hemorragia grave Damage control: a tactical alternative for the management of exanguinating trauma patients

RACIONAL: O choque hemorrágico persistente cursa com alta mortalidade. Grande importância tem sido dada para o "controle de danos" como opção terapêutica nestes casos. OBJETIVO: Avaliar a definição, indicações, técnicas e resultados do controle de danos no tratamento dos traumatizados com hemorragia grave. MÉTODO: Revisão bibliográfica. RESULTADOS: Como "controle de danos" entende-se a interrupção da operação antes que o choque hemorrágico alcance a sua fase irreversível, mesmo que as lesões encontradas não tenham o tratamento definitivo neste primeiro momento. Esta alternativa envolve três tempos: a operação abreviada, a recuperação na unidade de terapia intensiva e a reoperação programada. Desta forma, frente à acidose metabólica, hipotermia e coagulopatia, a operação é abreviada através do controle temporário da hemorragia e contaminação. São empregadas técnicas como o tamponamento hepático com compressas e ligadura de eventuais cotos intestinais. Na unidade de terapia intensiva são realizados o aquecimento do doente, restauração da volemia e débito cardíaco, e adequada oferta de oxigênio, além da reposição dos fatores de coagulação. Somente após a estabilização, o traumatizado é levado novamente ao centro cirúrgico para o tratamento definitivo das lesões. Trata-se de uma tática com bons resultados, mas que deve ser restrita a centros especializados, com supervisão cirúrgica contínua e recursos disponíveis para o tratamento de doentes graves. CONCLUSÃO: O controle de danos é opção prática nos casos de hemorragia grave, contudo deve ser empregado com julgamento crítico devido a complicações que podem decorrer da sua indicação.<br>BACKGROUND: Despite the advances in the treatment of exanguinating patients, hemorrhage remains as the leading cause of early deaths. A great deal of attention has been given to "damage control" as a therapeutic alternative in this scenario. AIM: To appraise the definition, indications, operative techniques and results of damage control for the treatment of exanguinating trauma patients. METHOD: Bibliographic review. RESULTS: Damage control introduces the concept of breaking the vicious cycle of metabolic acidosis, hypothermia and coagulopathy which results from hemorrhagic shock. Thus, the operation has to be interrupted before this irreversible stage, even if the injured organs were not given the definitive treatment at this moment. So, damage control involves three steps: an abbreviated operation, a recovering period in the intensive care unit, and the reoperation for the definitive treatment. At the abbreviated operation, operative techniques as stapling intestinal injuries or packing liver wounds are applied, allowing rapid control of the bleeding and spillage. In the intensive care unit, the patient is warmed, oxygen delivery and consumption are restored and coagulation factors administered. As soon as the hemodynamic stability, ideal body temperature and coagulation status are reached, the definitive operation is carried out. Damage control is a helpful option if correctly used. However, there are also severe complications that can occur. Therefore, it should be employed only in centers that could provide optimum resources. CONCLUSION: Damage control is an important tactical alternative for the treatment of exanguinating trauma patients