Effects of cilazapril and verapamil on myocardial iodine-125-metaiodobenzylguanidine accumulation in cardiomyopathic BIO 53.58 hamsters.
Sympathetic nervous system activation is important in the pathophysiology of congestive heart failure. However, little about how the treatment for heart failure may influence myocardial sympathetic nervous activity has been established. In this study, we evaluated effects of cilazapril (CLZ) and verapamil (VER) on myocardial sympathetic nervous activity in cardiomyopathic BIO 53.58 hamsters using [125I]metaiodobenzylguanidine ([125I]MIBG).


METHODS
We used BIO 53.58 hamsters aged 3, 6 and 10 mo and age-matched normal F1b hamsters. We divided BIO 53.58 hamsters into untreated, CLZ- and VER-treated groups. We measured myocardial [125I]MIBG uptakes and norepinephrine concentrations and evaluated the extent of fibrosis and the distribution of [125I]MIBG.


RESULTS
The myocardial [125I]MIBG uptake was significantly lower in BIO 53.58 hamsters aged 6 and 10 mo than in age-matched F1b hamsters. Myocardial [125I]MIBG uptake was significantly correlated to myocardial norepinephrine concentration in BIO 53.58 hamsters. Myocardial [125I]MIBG uptake was significantly higher in both of the treated groups than in the untreated group. The extent of myocardial fibrosis was significantly lower in both of the treated groups than in the untreated group. The myocardial [125I]MIBG uptake showed a significant inverse correlation with the extent of fibrosis. Myocardial [125I]MIBG distribution was highly heterogeneous in the untreated BIO 53.58 hamsters, whereas it was homogeneous in the F1b hamsters aged 6 mo and the treated BIO 53.58 hamsters.


CONCLUSIONS
In BIO 53.58 hamsters, myocardial [125I]MIBG uptake decreased with the progression of cardiomyopathy, and the decreased uptake was improved by treatment with CLZ and VER. Thus, myocardial [125I]MIBG uptake can reflect the effects of treatment on cardiomyopathy, as well as the progression of cardiomyopathy.
Wakabayashi
Y
Y
Department of Medicine III, Hamamatsu University School of Medicine, Japan.
Kurata
C
C
Mikami
T
T
Shouda
S
S
Okayama
K
K
Tawarahara
K
K
D019797:3-Iodobenzylguanidine; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000818:Animals; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000378:metabolism; D017315:Cilazapril / Q000627:therapeutic use*; D006224:Cricetinae; D006321:Heart / Q000000981:diagnostic imaging* / Q000294:innervation; D007457:Iodine Radioisotopes; D008297:Male; D008647:Mesocricetus; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009638:Norepinephrine / Q000378:metabolism; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013564:Sympathetic Nervous System / Q000503:physiopathology; D014700:Verapamil / Q000627:therapeutic use*
D000806:Angiotensin-Converting Enzyme Inhibitors; D002121:Calcium Channel Blockers; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D017315:Cilazapril; D019797:3-Iodobenzylguanidine; D014700:Verapamil; D009638:Norepinephrine