Akihisa Hanatani (1), Minoru Yoshiyama (1,*), Kazuhide Takeuchi (1),
Shokei Kim (2), Koji Nakayama (1), Takashi Omura (1), Hiroshi Iwao (2) and
Junichi Yoshikawa (1)
(1) First Department of Internal Medicine and (2) Department or Pharmacology,
Osaka City University Medical School, Osaka 545-0051, Japan
(*) To whom correspondence should be addressed.
Abstract: The purpose of this study was to analyze the effect
of the angiotensin II type 1-receptor antagonist candesartan cilexitil on
left ventricular systolic and diastolic function and mRNA expression of
contractile proteins, collagen, and Ca2+ handling protein in
myocardial-infarcted rats. After myocardial infarction, the animals were
randomly assigned to candesartan cilexitil-treated or untreated groups (MI).
We performed Doppler-echocardiographic examination and measured the hemodynamics
at four and twelve weeks after myocardial infarction. Following these measurements,
their cardiac mRNA was analyzed. At four weeks in MI, left ventricular end-diastolic
dimension increased (Control, 6.2+/-0.6 mm; MI, 8.7+/-0.6 mm; P<0.01),
fractional shortening decreased (Control, 41+/-5%; MI, 16+/-3%; P<0.01)
and E wave deceleration rate increased (Control, 14.3+/-2.0 m/sec2;
MI, 23.3+/-2.3 m/sec2; P<0.01). Candesartan cilexitil significantly
prevented these changes. The mRNA expressions of beta-myosin heavy chain,
alpha-skeletal actin, atrial natriuretic peptide, and collagens I and III
in the non-infarcted left ventricle and right ventricle were increased at
four weeks and were significantly suppressed by treatment with candesartan
cilexitil. At four weeks, Na+-Ca2+ exchanger mRNA
expression was increased, and candesartan cilexitil suppressed this increase.
At twelve weeks, sarcoplasmic reticulum Ca2+-ATPase mRNA expression
in the infarcted region including the adjacent non-infarcted left ventricle
and right ventricle were decreased and candesartan cilexitil restored it
to the control level. Candesartan cilexitil prevented the systolic and diastolic
dysfunction and abnormal cardiac mRNA expression in myocardial-infarcted
rats.
Keywords: Ventricular remodeling, Angiotensin II type 1-receptor antagonist,
Echocardiography, Gene expression, Diastolic function