Document Type

Journal Article

Department/Unit

School of Chinese Medicine

Language

English

Abstract

Hypertensive patients have been found to be associated with elevated levels of homocysteine, known as hyperhomocysteinemia. Homocysteine (Hcy) can induce endoplasmic reticulum (ER) stress in endothelial cells. This study aims to investigate whether black tea (BT) protects against hypertension-associated endothelial dysfunction through alleviation of ER stress. Rat aortae and cultured rat aortic endothelial cells were treated with Hcy, BT extract, and theaflavin-3,3′-digallate (TF3). Male Sprague Dawley rats were infused with angiotensin II (Ang II) to induce hypertension and orally administrated with BT extract at 15â €‰mg/kg/day for 2 weeks. Hcy impaired endothelium-dependent relaxations of rat aortae and led to ER stress in endothelial cells, which were ameliorated by co-incubation of BT extract and TF3. The blood pressure of Ang II-infused rats and plasma Hcy level were normalized by BT consumption. Impaired endothelium-dependent relaxations in renal arteries, carotid arteries and aortae, and flow-mediated dilatations in third-order mesenteric resistance arteries were improved. Elevations of ER stress markers and ROS level, plus down-regulation of Hcy metabolic enzymes in aortae from Ang II-infused rats were prevented by BT treatment. Our data reveal the novel cardiovascular benefits of BT in ameliorating vascular dysfunctions, providing insight into developing BT into beneficial dietary supplements in hypertensive patients.

Publication Date

5-2015

Source Publication Title

Scientific Reports

Volume

5

Start Page

10340

Publisher

Nature Publishing Group

Peer Reviewed

1

Copyright

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material.

Funder

This study was supported by Hong Kong General Research Fund (260712) and Natural Science Foundation of China (2012CB517805).

DOI

10.1038/srep10340

Link to Publisher's Edition

http://dx.doi.org/10.1038/srep10340

ISSN (print)

20452322

ISSN (electronic)

20452322

Additional Files

JA-4984-27856_suppl.pdf (324 kB)

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