Ginseng inhibits cardiomyocyte hypertrophy and heart failure via NHE-1 inhibition and attenuation of calcineurin activation.
BACKGROUND
Ginseng is a medicinal plant used widely in Asia that has gained popularity in the West during the past decade. Increasing evidence suggests a therapeutic role for ginseng in the cardiovascular system. The pharmacological properties of ginseng are mainly attributed to ginsenosides, the principal bioactive constituents in ginseng. The present study was carried out to determine whether ginseng exerts a direct antihypertrophic effect in cultured cardiomyocytes and whether it modifies the heart failure process in vivo. Moreover, we determined the potential underlying mechanisms for these actions.


RESULTS
Experiments were performed on cultured neonatal rat ventricular myocytes as well as adult rats subjected to coronary artery ligation (CAL). Treatment of cardiomyocytes with the α(1) adrenoceptor agonist phenylephrine (PE) for 24 hours produced a marked hypertrophic effect as evidenced by significantly increased cell surface area and ANP gene expression. These effects were attenuated by ginseng in a concentration-dependent manner with a complete inhibition of hypertrophy at a concentration of 10 μg/mL. Phenylephrine-induced hypertrophy was associated with increased gene and protein expression of the Na(+)-H(+) exchanger 1 (NHE-1), increased NHE-1 activity, increased intracellular concentrations of Na(+) and Ca(2+), enhanced calcineurin activity, increased translocation of NFAT3 into nuclei, and GATA-4 activation, all of which were significantly inhibited by ginseng. Upregulation of these systems was also evident in rats subjected to 4 weeks of CAL. However, animals treated with ginseng demonstrated markedly reduced hemodynamic and hypertrophic responses, which were accompanied by attenuation of upregulation of NHE-1 and calcineurin activity.


CONCLUSIONS
Taken together, our results demonstrate a robust antihypertrophic and antiremodeling effect of ginseng, which is mediated by inhibition of NHE-1-dependent calcineurin activation.
Guo
Juan
J
Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
Gan
Xiaohong Tracey
XT
Haist
James V
JV
Rajapurohitam
Venkatesh
V
Zeidan
Asad
A
Faruq
Nazo Said
NS
Karmazyn
Morris
M
D000818:Animals; D019703:Calcineurin / Q000378:metabolism*; D065095:Calcineurin Inhibitors; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004195:Disease Models, Animal; D050991:GATA4 Transcription Factor / Q000378:metabolism; D006333:Heart Failure / Q000378:metabolism / Q000517:prevention & control*; D006984:Hypertrophy / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D050778:NFATC Transcription Factors / Q000378:metabolism; D005894:Panax; D010656:Phenylephrine / Q000009:adverse effects; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism*
D065095:Calcineurin Inhibitors; D050991:GATA4 Transcription Factor; D050778:NFATC Transcription Factors; D010936:Plant Extracts; D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1; D010656:Phenylephrine; D012964:Sodium; D019703:Calcineurin; D002118:Calcium