P230 Type III collagen mRNA expression correlates with cardiac function.
1V.Arps, 1H.Eschert, 2J.Stypmann, 3H.H.Scheld, 3G.Plenz
1Institute for Arteriosclerosis Research, Muenster; 2Department of Cardiology and Angiology, University Hospital, Muenster; 3Department of Thoracic and Cardiovascular Surgery, University Hospital, Muenster.

Background: As the major structure of the interstitial matrix the collagen fibers contribute to the maintenance of cardiac function. Particularly, the composition of the collagen fibers determines the resilience and tensile strength of the heart and thus its functional capacity. Therefore, we studied the expression of fibrilar collagens (CI,CIII) in relation to changes in cardiac function in the canine model of adriamycin-induced cardiomyopathy.

Methods: In FBI dogs the deterioration of cardiac function was induced using repetitive intracoronary administration of adriamycin for five weeks (10mg/50ml saline over 1h per week). Besides acquisition of echocardiographic data, transmural left ventricular biopsies were taken before catheter insertion (control) and 6 weeks after adriamycin-administration. The mRNA was isolated and analyzed by RT-PCR for CI and CIII. Expression data were correlated with echocardiographic parameters. Results: Adriamycin-administration led to cardiac deterioration as reflected by echocardiographic data and by interstitial fibrosis as a result of increased expression of fibrilar CI and III. Regression analyses revealed that changes in CIII expression positively correlated with alterations in EDV, ESV, SV and CO (P<0.05), whereas they negatively correlated with EF (P<0.05). CI only positively correlated with CO (P<0.05).

Conclusions: Our data show that during the development of cardiomyopathy mainly alterations in the expression of CIII correlated with changes of parameters of both cardiac contractility and dilatation. This general deterioration of the cardiac performance is reflected by a decreased cardiac output. Thus, particularly alterations in the resilience of the collagen fiber define cardiac function.