Molecular Blood Test Could Diagnose Ischemic Stroke

Ischemic strokes, the most common and deadliest form of stroke, are caused when the contents of plaque in a major artery break away, forming a clot and blocking blood flow to the brain.

Quickly identifying whether a patient has had a stroke is critical as clot-busting treatments must be administered within hours to reverse damage and increase odds of a full recovery. No blood test exists for diagnosing stroke or identifying those who are at greatest risk for imminent stroke due to cardiovascular disease.

Scientists at Ochsner Medical Center (New Orleans, LA, USA) and their colleagues compared blood levels of non-coding ribonucleic acids (RNAs), molecules that regulate gene expression, in patients who had a stroke within five days to those who either had not had a stroke or had a stroke more than five days prior. They measured serum levels of micro-RNAs, miR-221, miR-222, miR-145, and circular RNA (circR)-284 in 24 asymptomatic (asymptomatic) and 17 acutely symptomatic patients ([urgent] ischemic cerebrovascular event within the previous five days) undergoing carotid endarterectomy.

The investigators found that miR-221 was significantly lower, whereas circR-284 was elevated in the serum of the urgent compared with the asymptomatic group. The ratio of serum circR-284: miR-221 was significantly elevated in the urgent group and exhibited favorable characteristics as a biomarker indicative of carotid plaque rupture and stroke. A validation study in 112 patients (47 asymptomatic, 41 urgent, and 24 patients with a cerebrovascular event between five and 180 days of the carotid endarterectomy [symptomatic]) confirmed elevation of serum circR-284:miR-221 uniquely in the urgent group and favorable sensitivity and specificity for detecting plaque rupture and stroke.

The authors concluded that serum circR-284: miR-221 has potential as a diagnostic biomarker of carotid plaque rupture and stroke. Moreover, they demonstrated the use of functionally related pairs of circulating noncoding RNAs as biomarkers in cardiovascular disease. Hernan A. Bazan, MD, an assistant professor of surgery and lead author of the study, said, “This work represents an important step towards understanding and predicting carotid-related strokes. Through ongoing translational studies such as this, we are aiming to develop better treatments and work towards preventing these episodes.” The study was published on August 4, 2017, in the journal Circulation: Cardiovascular Genetics.

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