Bone Marrow Support of the Heart in Pressure Overload Is Lost with Aging

Exogenous stem cell delivery is under investigation to prevent and treat cardiac dysfunction. It is less studied as to the extent endogenous bone marrow derived stem cells contribute to cardiac homeostais in response to stress and the affects of aging on this stress response.To determine the role of bone marrow (BM) derived stem cells on cardiac homeostasis in response to pressure overload (PO) and how this response is altered by aging.Young (8 weeks) and old (>40 weeks) C57/b6 mice underwent homo- and heterochronic BM transplantation prior to transverse aortic constriction (TAC). We found that older BM is associated with decreased cardiac function following TAC. This decreased function is associated with decrease in BM cell engraftment, increased myocyte apoptosis, decreased myocyte hypertrophy, increased myocardial fibrosis and decreased cardiac function. Additionally, there is a decrease in activation of resident cells within the heart in response to PO in old mice. Interestingly, these effects are not due to alterations in vascular density or inflammation in response to PO or differences in ex vivo stem cell migration between young and old mice.BM derived stem cells are activated in response to cardiac PO, and the recruitment of BM derived cells are involved in cardiac myocyte hypertrophy and maintenance of function in response to PO which is lost with aging

Adaptation of HIV-1 Depends on the Host-Cell Environment

Many viruses have the ability to rapidly develop resistance against antiviral drugs and escape from the host immune system. To which extent the host environment affects this adaptive potential of viruses is largely unknown. Here we show that for HIV-1, the host-cell environment is key to the adaptive potential of the virus. We performed a large-scale selection experiment with two HIV-1 strains in two different T-cell lines (MT4 and C8166). Over 110 days of culture, both virus strains adapted rapidly to the MT4 T-cell line. In contrast, when cultured on the C8166 T-cell line, the same strains did not show any increase in fitness. By sequence analyses and infections with viruses expressing either yellow or cyan fluorescent protein, we were able to show that the absence of adaptation was linked to a lower recombination rate in the C8166 T-cell line. Our findings suggest that if we can manipulate the host-cellular factors that mediate viral evolution, we may be able to significantly retard viral adaptability

Économie politique de l’Asie (1)

L’analyse hétérodoxe du développement asiatique n’est pas neuve, mais elle reste encore et toujours à approfondir. Ce travail est nécessaire en raison, d’une part de la taille de la région économique couverte, immense et très diverse, d’autre part de la méconnaissance dont elle pâtit en France, en particulier pour l’Asie du Sud-Est (mais aussi peut-être l’Asie du Sud), et enfin de la rapidité des changements qui s’y opèrent. Ce numéro consacré à l’économie politique asiatique contemporaine fait écho au dossier de la revue paru en 2012 sur Les capitalismes en Amérique latine, de l’économique au politique. Pour ces deux continents saisis par la mondialisation, la question majeure posée par la théorie de la régulation, à savoir les mécanismes à l’origine de la cohérence et de la viabilité des économies capitalistes, prend un relief particulier. Ici comme là, les économies étudiées se caractérisent par une foison d’architectures institutionnelles qui alimentent la diversité des capitalismes. >> lire la suite Heterodox analysis of Asian development is not new, as shown in the intellectual history of Ha-Joon Chang, retraced in the interview of this special issue, but there is still room for a great deal of in-depth analysis. This research is necessary because of the scale of the vast, extremely diverse economic region covered and the rapidity of the changes taking place, as well as the lack of knowledge concerning it in France. This issue devoted to contemporary Asian political economy echoes our special section on Capitalisms in Latin America, from economics to politics, published in Spring 2012. For these two continents in the throes of globalisation, the main question raised by Regulation theory – namely the mechanisms underlying the cohesiveness and viability of capitalist economies – assumes particular importance. In both instances, the economies studied are characterised by an abundance of institutional architectures feeding the diversity of capitalisms. >> read mor