Diabetes Alters Intracellular Calcium Transients in Cardiac Endothelial Cells

Diabetic cardiomyopathy (DCM) is a diabetic complication, which results in myocardial dysfunction independent of other etiological factors. Abnormal intracellular calcium ([Ca2+]i) homeostasis has been implicated in DCM and may precede clinical manifestation. Studies in cardiomyocytes have shown that diabetes results in impaired [Ca2+]i homeostasis due to altered sarcoplasmic reticulum Ca2+ ATPase (SERCA) and sodium-calcium exchanger (NCX) activity. Importantly, altered calcium homeostasis may also be involved in diabetes-associated endothelial dysfunction, including impaired endothelium-dependent relaxation and a diminished capacity to generate nitric oxide (NO), elevated cell adhesion molecules, and decreased angiogenic growth factors. However, the effect of diabetes on Ca2+ regulatory mechanisms in cardiac endothelial cells (CECs) remains unknown. The objective of this study was to determine the effect of diabetes on [Ca2+]i homeostasis in CECs in the rat model (streptozotocin-induced) of DCM. DCM-associated cardiac fibrosis was confirmed using picrosirius red staining of the myocardium. CECs isolated from the myocardium of diabetic and wild-type rats were loaded with Fura-2, and UTP-evoked [Ca2+]i transients were compared under various combinations of SERCA, sarcoplasmic reticulum Ca2+ ATPase (PMCA) and NCX inhibitors. Diabetes resulted in significant alterations in SERCA and NCX activities in CECs during [Ca2+]i sequestration and efflux, respectively, while no difference in PMCA activity between diabetic and wild-type cells was observed. These results improve our understanding of how diabetes affects calcium regulation in CECs, and may contribute to the development of new therapies for DCM treatment

Habitus de migrante: um conceito que visa captar o cotidiano dos atores em mobilidade espacial

A análise das populações em mobilidade espacial negligencia, com frequência, o poder da situação que elas atravessam. Apesar de suas diferenças estruturais, seus membros partilham, no cotidiano, o que a autora chamou de "habitus de migrante", uma segunda natureza que funciona como fonte dos recursos necessários à gestão do novo contexto. Esse conceito se baseia no conjunto das pesquisas qualitativas da autora sobre exilados, migrantes e estudantes no exterior, e em uma extensa literatura internacional sobre esses objetos. Seu status exploratório requer, no entanto, a elaboração de protocolos de pesquisa que possam colocar em evidência os mecanismos de mediação que permitam compreender as mudanças vividas por esses atores na diacronia.<br>The analysis of populations under spatial mobility often ignores the strength of the situation they live in. Despite of the structural differences that singularize them, the displacement situation leads those actors to share a number of characteristics in everyday life that the author has christened a "migrant'shabitus", a second nature that functions as a source of the resources needed to manage the new context. This concept, to which the author still gives an exploratory status, derives from the ethnographic research she has conducted on exiles, migrants and international students, as well as of an extended sociological literature on these groups; and intends to explain the changes these actors go under in a diachronic perspective