Cellular and functional defects in a mouse model of heart failure.

Journal Article (Journal Article)

Heart failure and dilated cardiomyopathy develop in mice that lack the muscle LIM protein (MLP) gene (MLP(-/-)). The character and extent of the heart failure that occurs in MLP(-/-) mice were investigated using echocardiography and in vivo pressure-volume (P-V) loop measurements. P-V loop data were obtained with a new method for mice (sonomicrometry) using two pairs of orthogonal piezoelectric crystals implanted in the endocardial wall. Sonomicrometry revealed right-shifted P-V loops in MLP(-/-) mice, depressed systolic contractility, and additional evidence of heart failure. Cellular changes in MLP(-/-) mice were examined in isolated single cells using patch-clamp and confocal Ca(2+) concentration ([Ca(2+)]) imaging techniques. This cellular investigation revealed unchanged Ca(2+) currents and Ca(2+) spark characteristics but decreased intracellular [Ca(2+)] transients and contractile responses and a defect in excitation-contraction coupling. Normal cellular and whole heart function was restored in MLP(-/-) mice that express a cardiac-targeted transgene, which blocks the function of beta-adrenergic receptor (beta-AR) kinase-1 (betaARK1). These data suggest that, despite the persistent stimulus to develop heart failure in MLP(-/-) mice (i.e., loss of the structural protein MLP), downregulation and desensitization of the beta-ARs may play a pivotal role in the pathogenesis. Furthermore, this work suggests that the inhibition of betaARK1 action may prove an effective therapy for heart failure.

Full Text

Duke Authors

Cited Authors

  • Esposito, G; Santana, LF; Dilly, K; Cruz, JD; Mao, L; Lederer, WJ; Rockman, HA

Published Date

  • December 2000

Published In

Volume / Issue

  • 279 / 6

Start / End Page

  • H3101 - H3112

PubMed ID

  • 11087268

International Standard Serial Number (ISSN)

  • 0363-6135

Digital Object Identifier (DOI)

  • 10.1152/ajpheart.2000.279.6.H3101


  • eng

Conference Location

  • United States