Coffee: Caffeine Improves Microvascular Endothelial Function

MedicalResearch.com Interview with:
Masato Tsutsui, MD, PhD, FAHA
Professor and Chairman
Department of Pharmacology
Graduate School of Medicine
University of the Ryukyus
Okinawa 903-0215, Japan

MedicalResearch.com: What are the main findings of the study?

Dr. Tsutsui: A recent large prospective study reported that coffee consumption is associated with reduced mortality for cardiovascular disease (NEJM 2012).  However, its precise mechanisms remain to be clarified.  Our double-blind, placebo-controlled, crossover study demonstrated, for the first time, that caffeine contained in a cup of coffee ameliorates microvascular endothelial function in healthy individuals.  These findings may explain, at least in part, the association of coffee consumption with reduced mortality for cardiovascular disease.

MedicalResearch.com: Were any of the findings unexpected?


Dr. Tsutsui:  Coffee might adversely affect cardiovascular health.  However, our study suggests that caffeinated coffee improves microvascular endothelial function.  What this beneficial effect was observed by only a cup of caffeinated coffee is also an interesting finding.

MedicalResearch.com: What should clinicians and patients take away from this study?

Dr. Tsutsui: Our study subjects were healthy persons.  Whether or not caffeine contained in a cup of coffee is beneficial to patients with cardiovascular disease remains to be examined in future studies.

MedicalResearch.com: What further research do you recommend as a result of your study?

Dr. Tsutsui: We examined only a small number of subjects (n=27).  Our findings should be confirmed by large-scale clinical studies.  Furthermore, whether or not caffeine contained in a cup of coffee is beneficial to patients with cardiovascular disease also should be studied.

Addendum:

Dr. Tsutsui: Although the AHA News Release says that caffeine contained in a cup of coffee improves finger blood flow, it is not correct.  Correctly, it improved reactive hyperemia of finger blood flow.  Let me explain reactive hyperemia of finger blood flow.  Reactive hyperemia is a marker of vascular endothelial function, and reactive hyperemia of finger blood flow is a marker of microvascular endothelial function.  Reactive hyperemia of finger blood flow was measured by laser Doppler flowmetry.  A flow-probe of laser Doppler flowmetry was placed at the tip of the left index finger or thumb, and a manchette was placed on the left upper arm.  Reactive hyperemia of finger blood flow was induced by inflating a manchette for 1 minute in order to interrupt finger arterial blood flow, and then deflating the manchette.  Reactive hyperemia was evaluated by the extent of an increase in finger blood flow after deflating a manchette.  Caffeine contained in a cup of coffee improved reactive hyperemia of finger blood flow, but not finger blood flow.

Citation:

Presented at the 2013 American Heart Association

American Heart Association Meeting Report: Abstract 12428 (Hall F, Core 7, Poster Board: 7062)
Co-authors are Katsuhiko Noguchi, Ph.D.; Toshihiro Matsuzaki, M.D., Ph.D.; Mayuko Sakanashi, Ph.D.; Naobumi Hamadate, Ph.D.; Taro Uchida; B.Sc.; Mika Kina-Tanada, D.D.S.; Haruaki Kubota, M.D.; Junko Nakasone, Ph.D.; Matao Sakanashi, M.D., Ph.D.; Fumihiko Kamezaki, M.D., Ph.D.; Akihide Tanimoto, M.D., Ph.D.; Nobuyuki Yanagihara, Ph.D.; Yusuke Ohya, M.D., Ph.D.; Hiroaki Masuzaki, M.D., Ph.D.; and Shogo Ishiuchi, M.D., Ph.D.