The impact of the catechol-O-methyltransferase genotype on vascular function and blood pressure after acute green tea ingestion.
METHODS
Evidence for the benefits of green tea catechins on vascular function is inconsistent, with genotype potentially contributing to the heterogeneity in response. Here, the impact of the catechol-O-methyltransferase (COMT) genotype on vascular function and blood pressure (BP) after green tea extract ingestion are reported.


RESULTS
Fifty subjects (n = 25 of the proposed low-activity [AA] and of the high-activity [GG] COMT rs4680 genotype), completed a randomized, double-blind, crossover study. Peripheral arterial tonometry, digital volume pulse (DVP), and BP were assessed at baseline and 90 min after 1.06 g of green tea extract or placebo. A 5.5 h and subsequent 18.5 h urine collection was performed to assess green tea catechin excretion. A genotype × treatment interaction was observed for DVP reflection index (p = 0.014), with green tea extract in the AA COMT group attenuating the increase observed with placebo. A tendency for a greater increase in diastolic BP was evident at 90 min after the green tea extract compared to placebo (p = 0.07). A genotypic effect was observed for urinary methylated epigallocatechin during the first 5.5 h, with the GG COMT group demonstrating a greater concentration (p = 0.049).


CONCLUSIONS
Differences in small vessel tone according to COMT genotype were evident after acute green tea extract.
Department of Food and Nutritional Sciences, University of Reading, Reading, UK.
Rosalind J
RJ
Miller
Kim G
KG
Jackson
Tony
T
Dadd
Andrew E
AE
Mayes
A Louise
AL
Brown
Julie A
JA
Lovegrove
Anne M
AM
Minihane
D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D001808:Blood Vessels / Q000502:physiology*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism / Q000652:urine; D002394:Catechol O-Methyltransferase / Q000235:genetics* / Q000378:metabolism; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D056726:Genetic Association Studies; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry; D020641:Polymorphism, Single Nucleotide; D055815:Young Adult
C518873:4'-O-methylepigallocatechin; D010936:Plant Extracts; D002392:Catechin; D002394:Catechol O-Methyltransferase