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Type II diabetic mice exhibit contractile dysfunction but maintain cardiac output by favourable loading conditions

2006; Elsevier BV; Volume: 8; Issue: 8 Linguagem: Inglês

10.1016/j.ejheart.2006.03.001

1879-0844

An Van den Bergh, Willem Flameng, Paul Herijgers,

Adipose Tissue and Metabolism

Abstract Background Cardiomyopathy in type II diabetes is incompletely understood. The leptin receptor‐deficient (db/db) mouse is a well‐accepted model of type II diabetes. To date, left ventricular contractility has not been studied in animal models of type II diabetes with in vivo load‐independent parameters. Aim To determine cardiac function in db/db mice in vivo. Methods Cardiac function in 12‐ and 24‐week‐old db/db and wild‐type mice was assessed using a microtip‐pressure‐conductance catheter. Results Left ventricular contractile dysfunction, measured by load‐independent parameters (preload recruitable stroke work, end‐systolic elastance, d P /d t ‐ V ed ), is present in diabetic mice from age 24 weeks onwards. Despite this contractile dysfunction, the conventional parameters cardiac output, ejection fraction and d P /d t max were maintained, which was due to an increased preload and decreased afterload. Ventriculo‐arterial coupling was increased and mechanical efficiency significantly reduced in db/db mice. Conclusion Our results demonstrate that, despite impaired cardiac contractility and mechanical efficiency, cardiac output is maintained in db/db mice by favourable loading conditions and that in vivo load‐independent measurements are necessary to fully characterize cardiac performance in animal models of pathophysiological states.