CHANGES OF THE COLLAGEN COMPOSITION IN THE HEART CAUSED BY MICROCURRENT APPLICATION. AN EXPLANATION FOR THE IMPROVEMENT OF CARDIAC FUNCTION BY BI-VENTRICULAR PACING?
Johannes Müller, Barbara Kapeller, Gerd Wallukat and Karin Macfelda
Berlin Heart Berlin, Germany; Institute of Biomedical Research Vienna, Austria
OBJECTIVE: Improvement of cardiac function by the unloading effect of a cardiac assist device mainly depends on the duration of heart failure (HF). Patients with a short history of HF (< 5years) show improvement due to reverse remodeling of the myocytes and in particular of the collagen composition of the extracellular matrix. In contrast, one reason why patients with longterm heart failure (> 5 years) do not show significant cardiac functionimprovement is that the collagen composition of the extracellular matrix is irreversible.
It is successful clinical practice to apply microcurrent in patients with bone fractures andwound healing disturbances in order to improve the healing process by modulation of thecollagen synthesis.
In order to examine whether microcurrent can also influence the collagen synthesis in the myocardium, the effect of microcurrent application on collagen synthesis of adult cardiomyocytes was investigated.
METHODS: Adult cardiomyocytes were isolated and cultivated in 24 well cell culture plates. Current of different magnitudes (0, 20, 40, 60, 80, 100 :A) was applied via platinum electrodes by a special custom-made device. The whole equipment was incubated under cell culture conditions (+37°C, 5% CO2) over a period of 7 days. Changes of the collagen type I and type III synthesis were analyzed using immunohistochemical staining methods. Collagen type I andtype III content was quantified using a special fluorescence confocal laser scanning microscopy system including special analysis software.
RESULTS: Compared to cardiomyocytes exposed to 0 :A (control cells), collagen type I synthesis of cardiomyocytes showed no significant change after exposure to a moderate current magnitude(40, 60 :A) but a highly significant mean decrease (20.6 %) if exposed to high current (80, 100 :A). Collagen type III revealed a mean increase at moderate current of 29.7 % and a decrease of 25.2 % at high current exposure. As a side effect, we detected an increase in the cell proliferation rate at moderate and high current.
CONCLUSION: The results obtained in cell culture suggest that the application of micro-current is able to modulate the synthesis of collagen. In particular, in dependency of the current magnitude collagen type I can be up- or down-regulated. Collagen type I is responsible for the stiffness and the degree of dilatation of the heart. Therefore it can be envisaged that this method -if applied clinically - may help to improve cardiac function, as it helps to heal bone fractures.
Xanya Sofra Weiss
No comments:
Post a Comment