NOX2, p22phox and p47phox are targeted to the nuclear pore complex in ischemic cardiomyocytes colocalizing with local reactive oxygen species.

BACKGROUND: NADPH oxidases play an essential role in reactive oxygen species (ROS)-based signaling in the heart. Previously, we have demonstrated that (peri)nuclear expression of the catalytic NADPH oxidase subunit NOX2 in stressed cardiomyocytes, e.g. under ischemia or high concentrations of homocysteine, is an important step in the induction of apoptosis in these cells. Here this ischemia-induced nuclear targeting and activation of NOX2 was specified in cardiomyocytes. METHODS: The effect of ischemia, mimicked by metabolic inhibition, on nuclear localization of NOX2 and the NADPH oxidase subunits p22(phox) and p47(phox), was analyzed in rat neonatal cardiomyoblasts (H9c2 cells) using Western blot, immuno-electron microscopy and digital-imaging microscopy. RESULTS: NOX2 expression significantly increased in nuclear fractions of ischemic H9c2 cells. In addition, in these cells NOX2 was found to colocalize in the nuclear envelope with nuclear pore complexes, p22(phox), p47(phox) and nitrotyrosine residues, a marker for the generation of ROS. Inhibition of NADPH oxidase activity, with apocynin and DPI, significantly reduced (peri)nuclear expression of nitrotyrosine. CONCLUSION: We for the first time show that NOX2, p22(phox) and p47(phox) are targeted to and produce ROS at the nuclear pore complex in ischemic cardiomyocytes

Water displacement leg volumetry in clinical studies - A discussion of error sources

<p>Abstract</p> <p>Background</p> <p>Water displacement leg volumetry is a highly reproducible method, allowing the confirmation of efficacy of vasoactive substances. Nevertheless errors of its execution and the selection of unsuitable patients are likely to negatively affect the outcome of clinical studies in chronic venous insufficiency (CVI).</p> <p>Discussion</p> <p>Placebo controlled double-blind drug studies in CVI were searched (Cochrane Review 2005, MedLine Search until December 2007) and assessed with regard to efficacy (volume reduction of the leg), patient characteristics, and potential methodological error sources. Almost every second study reported only small drug effects (≤ 30 mL volume reduction). As the most relevant error source the conduct of volumetry was identified. Because the practical use of available equipment varies, volume differences of more than 300 mL - which is a multifold of a potential treatment effect - have been reported between consecutive measurements. Other potential error sources were insufficient patient guidance or difficulties with the transition from the Widmer CVI classification to the CEAP (Clinical Etiological Anatomical Pathophysiological) grading.</p> <p>Summary</p> <p>Patients should be properly diagnosed with CVI and selected for stable oedema and further clinical symptoms relevant for the specific study. Centres require a thorough training on the use of the volumeter and on patient guidance. Volumetry should be performed under constant conditions. The reproducibility of short term repeat measurements has to be ensured.</p

Accumulation of fibronectin in the heart after myocardial infarction: a putative stimulator of adhesion and proliferation of adipose-derived stem cells

Stem cell therapy is a promising treatment after myocardial infarction (MI). A major problem in stem cell therapy, however, is that only a small proportion of stem cells applied to the heart can survive and differentiate into cardiomyocytes. We hypothesized that fibronectin in the heart after MI might positively affect stem cell adhesion and proliferation at the site of injury. Therefore, we investigated the kinetics of attachment and proliferation of adipose-tissue-derived stem cells (ASC) on fibronectin and analysed the time frame and localization of fibronectin accumulation in the human heart after MI. ASCs were seeded onto fibronectin-coated and uncoated culture wells. The numbers of adhering ASC were quantified after various incubation periods (5-30 min) by using DNA quantification assays. The proliferation of ASC was quantified after culturing ASC for various periods (0-9 days) by using DNA assays. Fibronectin accumulation after MI was quantified by immunohistochemical staining of heart sections from 35 patients, after different infarction periods (0-14 days old). We found that ASC attachment and proliferation on fibronectin-coated culture wells was significantly higher than on uncoated wells. Fibronectin deposition was significantly increased from 12 h to 14 days post-infarction, both in the infarction area and in the border-zone, compared with the uninfarcted heart. Our results suggest that a positive effect of fibronectin on stem cells in the heart can only be achieved when stem cell therapy is applied at least 12 h after MI, when the accumulation of fibronectin occurs in the infarcted heart. © 2008 The Author(s)

NADPH oxidases in cardiovascular disease: insights from in vivo models and clinical studies

NADPH oxidase family enzymes (or NOXs) are the major sources of reactive oxygen species (ROS) that are implicated in the pathophysiology of many cardiovascular diseases. These enzymes appear to be especially important in the modulation of redox-sensitive signalling pathways that underlie key cellular functions such as growth, differentiation, migration and proliferation. Seven distinct members of the family have been identified of which four (namely NOX1, 2, 4 and 5) may have cardiovascular functions. In this article, we review our current understanding of the roles of NOX enzymes in several common cardiovascular disease states, with a focus on data from genetic studies and clinical data where available

Influência da altura do salto de sapatos na função venosa da mulher jovem Influence of shoe heel height on venous function in young women

CONTEXTO: A influência da altura do salto de sapatos na função venosa é ainda assunto controverso na literatura mundial. A importância da ergonomia na qualidade de vida é um fator consagrado e situações que a prejudiquem como permanência prolongada na posição supina, qualidade dos calçados e condições do local de trabalho podem interferir na saúde do indivíduo. OBJETIVO: Estudar a influência da altura do salto do sapato na drenagem venosa dos membros inferiores, utilizando-se a pletismografia a ar (PGA). MÉTODO: Quinze mulheres, com idade média de 24,6 anos, assintomáticas, utilizando calçados de tamanhos apropriados, foram examinadas em três momentos: descalças (0 cm), salto médio (3,5 cm) e alto (7 cm). Apresentavam índice de massa corporal < 25 e foram classificadas de acordo com a Classificação Internacional CEAP, em critérios: clínico (C0 ou C1), etiológico (Ep), anatômico (As) e fisiopatológico (Pr). Os valores do índice de enchimento venoso (IEV), da fração de ejeção (FE) e da fração de volume residual (FVR) foram separados em três categorias pela altura do salto e comparados entre si, utilizando-se a análise de variância para médias repetidas (ANOVA). RESULTADOS: Houve diminuição da FE e aumento da FVR no grupo de salto alto em relação ao grupo descalço (p < 0,005). Não ocorreu diferença desses parâmetros entre o grupo de salto médio e os outros grupos. O IEV comportou-se de maneira semelhante nas três situações avaliadas. CONCLUSÃO: O salto alto diminui a função de bomba muscular demonstrado pela queda da FE e aumento da FVR, podendo, com o seu uso contínuo, provocar hipertensão venosa nos membros inferiores, o que poderia ser preditivo de sintomatologia na doença venosa.<br>BACKGROUND: The influence of shoe heel height on venous function is still a controversial subject in the international literature. The importance of ergonomics for quality of life is a universally accepted factor, and situations that impair it, such as prolonged permanence in the supine position, shoe quality and workplace conditions may interfere with the individual"s health. OBJECTIVE: To analyze the influence of shoe heel height on lower limb venous drainage using air plethysmography. METHOD: Fifteen asymptomatic women with mean age of 24.6 years, wearing shoes of appropriate size were examined in three different situations: barefoot (0 cm), medium heels (3.5 cm) and high heels (7 cm). Body mass index was < 25 and the subjects were classified according to the CEAP International Classification based on clinical (C0 or C1), etiologic (Ep), anatomic (As) and physiopathological (Pr) criteria. The values of venous filling index (VFI), ejection fraction (EF) and residual volume fraction (RVF) were divided into three categories according to heel height and compared to one another by repeated means analysis of variance (ANOVA). RESULTS: EF was decreased and RVF was increased in the high heel group compared to the barefoot group (p < 0.005). These parameters did not differ between the medium heel group and the other groups. VFI showed a similar behavior in the three situations evaluated. CONCLUSION: High heels reduce muscle pump function, as demonstrated by the fall in EF and increase in RVF, and their continued use may provoke venous hypertension in the lower limbs, possibly representing a predictive factor of venous disease symptoms