December 18, 2014

Atrial disease and hypertension links

New findings suggest that misfolded proteins accumulate in the heart atria, particularly in patients with hypertension, and may contribute to atrial heart disease.

Illustration of heart

Preamyloid oligomers – precursors of the insoluble, misfolded proteins linked to aging-related degenerative diseases such as Alzheimer disease – are present in human heart atria, according to new findings from Vanderbilt investigators. While atrial amyloidosis (accumulation of amyloid) can develop with aging, the presence of preamyloid oligomers in atrial tissue had not been previously investigated.

Katherine Murray, M.D., and colleagues analyzed atrial tissue samples collected during elective heart surgery for aortic valve replacement, coronary artery bypass grafting and mitral valve replacement. Patients did not have a history of atrial arrhythmias, congestive heart failure or cardiomyopathy.

The researchers detected preamyloid oligomers, heterogeneously distributed throughout the myocardium, in a majority of the atrial samples. Preamyloid oligomer burden was independently associated with the presence of clinical hypertension, which is the most important comorbidity contributing to atrial fibrillation.

The findings, reported recently in the Journal of the American Heart Association, provide evidence for a novel potential mechanism whereby hypertension can promote atrial pathology.

This research was supported by grants from the National Institutes of Health (HL096844, GM007569, TR000445) and the American Heart Association, Southeast Affiliate.

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