Issue: June 2017
May 02, 2017
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Nutrient raising TMAO level linked to platelet hyperresponsiveness, but aspirin mitigates effect

Issue: June 2017
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Supplementation with choline, a nutrient abundant in a Western diet, raised trimethylamine N-oxide levels and increased risk for platelet hyperresponsiveness, but the effect can be mitigated by low-dose aspirin, researchers reported in Circulation.

“This is the first time, as far as I am aware, that you could directly link a specific dietary nutrient to changing platelet function,” Stanley L. Hazen, MD, PhD, chair of the department of cellular and molecular medicine in the Lerner Research Institute and head of preventive cardiology and rehabilitation in the Miller Family Heart & Vascular Institute at Cleveland Clinic, told Cardiology Today.

Hazen and colleagues administered choline bitartrate at a level of approximately 200 mg free choline twice daily for 2 months (mean intake, 302 mg per day) to 18 volunteers (eight vegetarian or vegan, 10 omnivores; mean age, 46 years; 40% men) without CHD or major risk factors.

Stanley L. Hazen, MD, PhD
Stanley L. Hazen

Platelet aggregation affected

At 1 month and 2 months, levels of plasma trimethylamine N-oxide (TMAO), a choline metabolite produced from gut microbiota and linked to atherogenesis and thrombosis, increased 10-fold in the vegetarian/vegan group and 15-fold in the omnivore group (P < .01 for both), according to the researchers.

In all participants, there was an association between change in TMAO level and change in platelet aggregation (Spearman rho = 0.38; P < .03).

Omnivores not taking aspirin were then, after a choline-free washout period, administered aspirin 81 mg per day for 1 month, followed by both choline and continued aspirin for another 2 months. Aspirin was associated with a 40% decrease in the level of TMAO and a significant reduction in platelet hyperresponsiveness at 1 month (P = .006) and 2 months (P = .009).

Taking a baby aspirin reduced TMAO by about 40% and also reduced the prothrombotic effects of TMAO,” Hazen, a member of the Cardiology Today Editorial Board, said in an interview. However, the data suggest that “in people who are at high risk for heart disease, if they have a high level of TMAO, just a simple baby aspirin may not be enough.”

Implications for patients

Hazen said the implication for primary prevention is that “these studies, along with others showing high TMAO predicts CV events and thrombotic events, collectively argue that a person in primary prevention with a high TMAO is at a higher thrombotic and CV event risk, and as long as there’s no contraindication, they should consider a low-dose aspirin.”

Patients in secondary prevention with high TMAO levels should modify their diet and “there should be consideration for dual antiplatelet therapy or a more aggressive antithrombosis prophylaxis type of approach,” Hazen said. Although these patients do not need to switch to a vegetarian or vegan diet immediately, “I do suggest that they cut back on the red meat and at least start to eat vegetarian at least 2 days per week and see how that goes,” he said. “Over time, they can slowly increase that.” – by Erik Swain

Disclosure: Hazen reports being named as a co-inventor on pending and issued patents held by Cleveland Clinic relating to CV diagnostics and therapeutics, consulting for Esperion and Proctor & Gamble, receiving research funds from Proctor & Gamble, Pfizer, Roche Diagnostics and Takeda and receiving royalties from Cleveland HeartLab, Esperion, Frantz Biomarkers LLC, Proctor & Gamble and Siemens. Another researcher reports being named as a co-inventor on pending and issued patents held by Cleveland Clinic and receiving royalties from Cleveland HeartLab.