Green tea modulation of inducible nitric oxide synthase in hypoxic/reoxygenated cardiomyocytes.
Hypoxia/reoxygenation (H/R) is one of the causes of the increased expression of inducible nitric oxide synthase (iNOS) in cardiomyocytes. Since an aberrant NOS induction has detrimental consequences, we evaluated the effect of a green tea extract (GTE) on the NOS induction and activity in H/R-cardiomyocytes to define a nutritional strategy. Cultured rat cardiomyocytes were exposed to H/R in the presence of two concentrations of a green tea extract (GTE), which is reported to inhibit NOS expression and activity in different cells. In cultured cardiomyocytes two NOS isoforms were constitutively expressed, but only iNOS was induced by H/R. GTE supplementation at the lowest concentration, comparable to that in human plasma after dietary consumption, was ineffective, while the highest, comparable to that achievable by dietary supplements, counteracted the effect of H/R on iNOS induction and activity. It is necessary to verify in humans the relationship between the modulation of NO production and green tea dietary consumption.
Agnetti
G
G
Department of Biochemistry G. Moruzzi, Centro Studi e Ricerche sul Metabolismo Cardiaco, University of Bologna, Via Irnerio, 48-4016 Bologna, Italy.
Bordoni
A
A
Angeloni
C
C
Leoncini
E
E
Guarnieri
C
C
Caldarera
C M
CM
Biagi
P L
PL
Hrelia
S
S
D000818:Animals; D015687:Cell Hypoxia; D002478:Cells, Cultured; D019587:Dietary Supplements; D015971:Gene Expression Regulation, Enzymologic; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013662:Tea
D013662:Tea; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D010100:Oxygen