Showing papers by "Tetsuo Shioi published in 2001"

Progressive atrioventricular conduction defects and heart failure in mice expressing a mutant Csx/Nkx2.5 homeoprotein

Abstract: A DNA nonbinding mutant of the NK2 class homeoprotein Nkx2.5 dominantly inhibits cardiogenesis in Xenopus embryos, causing a small heart to develop or blocking heart formation entirely. Recently, ten heterozygous CSX/NKX2.5 homeoprotein mutations were identified in patients with congenital atrioventricular (AV) conduction defects. All four missense mutations identified in the human homeodomain led to markedly reduced DNA binding. To examine the effect of a DNA binding–impaired mutant of mouse Csx/Nkx2.5 in the embryonic heart, we generated transgenic mice expressing one such allele, I183P, under the β-myosin heavy chain promoter. Unexpectedly, transgenic mice were born apparently normal, but the accumulation of Csx/Nkx2.5(I183P) mutant protein in the embryo, neonate, and adult myocardium resulted in progressive and profound cardiac conduction defects and heart failure. P-R prolongation observed at 2 weeks of age rapidly progressed into complete AV block as early as 4 weeks of age. Expression of connexins 40 and 43 was dramatically decreased in the transgenic heart, which may contribute to the conduction defects in the transgenic mice. This transgenic mouse model may be useful in the study of the pathogenesis of cardiac dysfunction associated with CSX/NKX2.5 mutations in humans.

Proinflammatory cytokine inhibitor prolongs the survival of rats with heart failure induced by pressure overload.

Abstract: Although an increased expression of proinflammatory cytokines has been reported in cardiac tissue samples from patients with congestive heart failure (CHF) and in various animal models of CHF, the role of these cytokines in the disease remains to be determined. Dahl salt-sensitive (DS) rats fed a high salt diet develop hypertension, cardiac hypertrophy and eventually CHF. In the present study, DS rats were treated with FR167653 (1-[7-(4-fluorophenyl)-1,2,3,4-tetrahydro-8-(4-pyridyl)pyrazolo[5,1-c][1,2,4]triazin-2-yl]-2-phenylethanedione sulfate monohydrate), a new low molecular weight inflammatory cytokine inhibitor. Treatment with 10 mg/kg per day of FR167653 significantly prolonged the survival of the animals and also prevented the bodyweight loss associated with heart failure. In conclusion, a non-peptide proinflammatory cytokine inhibitor improved the survival of animals with heart failure.