Imaging neuroinflammation after brain injuries by ultrasensitive MRI and two-photon laser-scanning microscopy.

Worldwide, stroke is the leading cause of disability in the aging population. Neuroinflammation is a common feature of acute stroke and is considered to be a major obstacle to endogenous neurogenesis and exogenously administered stem cells. Therefore, drug and cell therapies aimed at suppressing post-stroke inflammation have emerged as a promising approach to improve recovery after stroke. However, progress toward the development of efficient cell-based therapies for ischemic stroke has been disappointing mainly because the interplay between host neuroinflammation and stem cell-based therapies during the acute stroke and the recuperation phase is virtually unknown. The pathophysiological evolution of stroke events indeed seems driven by complex cellular interactions between several different cell types whose sequential recruitments have been insufficiently documented due to the lack of respective technologies, in particular, of non-invasive imaging modalities. The development of in vivo ultrasensitive magnetic resonance imaging (MRI) and two-photon laser-scanning microscopy has revolutionized our understanding of neuroinflammation. Therefore, the purpose of this review is to highlight the interplay between host neuroinflammation, which is considered to be a major obstacle to exogenous-mediated neuronal precursor cells, and exogenously administered stem cells.