Trainingstherapie bei Herzinsuffizienz

[Cardiac rehabilitation in heart failure]

Heart failure is a malignant disorder with increasing prevalence and a high socioeconomic impact. Sceletal muscle myopathy seems to play a key role in the development of exercise intolerance. Cardiac rehabilitation for heart failure mainly adresses training, namely moderate continuous endurance training or interval training in combination with resistance training, and is highly recommended in the current ESC-guidelines. Following a multimodal concept cardiac rehabilitation also implements optimisation of neurohumoral therapy, education and counselling to empower self-care as well as psychosocial support.

Role of ROS and RNS Sources in Physiological and Pathological Conditions

There is significant evidence that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. Mitochondria have been thought to both play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including stimulation of opening of permeability transition pores. Until recently, the functional significance of ROS sources different from mitochondria has received lesser attention. However, the most recent data, besides confirming the mitochondrial role in tissue oxidative stress and protection, show interplay between mitochondria and other ROS cellular sources, so that activation of one can lead to activation of other sources. Thus, it is currently accepted that in various conditions all cellular sources of ROS provide significant contribution to processes that oxidatively damage tissues and assure their survival, through mechanisms such as autophagy and apoptosis.

[Exercise training as a key component of heart failure therapy]

Physical exercise has been recognized as a standard therapy in the guidelines for secondary prevention of chronic heart failure. In clinical practice its benefits are widely underestimated. It is still too rarely applied as a therapeutic component, despite overwhelming scientific evidence, including meta-analyses illustrating the positive effect on exercise capacity, quality of life and hospitalization. It is crucial that patients undergo a thorough clinical investigation, including exercise testing and are in a clinically stable condition for at least 6 weeks under optimal guideline-conform medicinal therapy before exercise training is initiated. Moreover, it is important that only approved exercise regimens should be prescribed and exercise sessions should be appropriately monitored. Both moderate continuous endurance training and recently developed interval training have been shown to be safe and effective in chronic heart failure. Ideally, endurance training should be combined with moderate resistance training. Current evidence clearly demonstrates a dose-response relationship in the way that beneficial effects of exercise training are strongly related to factors such as exercise duration and intensity. Development of strategies that support long-term adherence to exercise training are a crucial challenge for both daily practice and future research.

Integration target site selection for retroviruses and transposable elements

When a retrovirus infects a cell, its RNA genome is reverse transcribed into a double-stranded DNA, which is then permanently integrated into the host chromosome. Integration is one of the essential steps in the retroviral life cycle. Many transposable elements also move around and integrate into the host genome as part of their life cycle, some through RNA intermediates and some through 'cut and paste' mechanisms. Integration of retroviruses and transposable elements into 'sensitive areas' of the genome can cause irreparable damage. On the other hand, because of their ability to integrate permanently, and the relatively efficient rates of transgenesis, retroviruses and transposable elements are widely used as gene delivery tools in basic research and gene therapy trials. Recent events in gene therapy treatments for X-linked severe combined immunity deficiencies (X-SCID) have highlighted both the promise and some of the risks involved with utilizing retroviruses. Nine of 11 children were successfully treated for X-SCID using a retrovirus carrying the gene mutated in this disease. However, later two of these children developed leukemias because of retroviral integrations in the putative oncogene LMO2 [1]. A third child has also been demonstrated to have an integration in LMO2, but is as of yet nonsymptomatic [2]. It is a bit difficult to explain the high frequency of integrations into the same gene using a random model of retroviral integration, and there has been evidence for decades that retroviral integrations may not be random. But the data were somewhat limited in their power to determine the precise nature of the integration biases. The completion of the human genome sequence coupled with sensitive polymerase chain reaction techniques and an ever-decreasing cost of sequencing has given a powerful new tool to the study of integration site selection. In this review, we describe the findings from several recent global surveys of target site selection by retroviruses and transposable elements, and discuss the possible ramifications of these findings to both mechanisms of action and to the use of these elements as gene therapy vectors.