Researchers found a novel blood biomarker for penumbra in acute ischemic stroke
The penumbra means a dysfunctional but reversible brain tissue affected by hypoperfusion due to vessel occlusion, especially in ischemic stroke. Treating acute ischemic stroke is mainly to salvage the dying penumbra. Recently established evaluation of the penumbra using perfusion imaging with automated analysis software has converted brain tissue analysis from “time-based” to “tissue-based” approach. Moreover, a recent advance of reperfusion therapies has greatly improved the prognosis of stroke, which led to emphasis of the significance of the penumbra. However, as the penumbra evaluation requires experts with special technologies, easily accessed blood biomarkers for the penumbra have been awaited.
Hiroyuki Ishiyama and colleagues found a peptide named mid-regional pro-adrenomedullin (MR-proADM) as a useful blood biomarker for the penumbra in hyperacute ischemic stroke. They evaluated the penumbra with an established method by measuring ’clinical-core mismatch’ which means discrepancy between clinical symptoms and image-based area of dead brain tissues. A higher mismatch means a broader salvageable brain tissue. Patients with higher mismatch presented with higher plasma MR-proADM levels compared to those without (0.81 vs. 0.61 nmol/L, P < 0.001). MR-proADM levels were also correlated with the penumbra volume calculated by automated software (See Figure).
“If MR-proADM can be established as a blood biomarker for the ischemic penumbra, it enables not only the early diagnosis of hyperacute ischemic stroke but also the triage of patients who require reperfusion therapies. The results of the current study could dramatically change the clinical practice of the stroke patients” – Dr. Masafumi Ihara, PI of this study, said.
Figure. The correlation between the penumbra volume and plasma MR-proADM levels. Numbers in each circle indicate the ischemic core volumes (mL).
The current research has been published in Brain pathology, the official journal of the International Society of Neuropathology, as “Plasma mid-regional pro-adrenomedullin: A biomarker of the ischemic penumbra in hyperacute stroke” (DOI: 10.1111/bpa.13110).