Perivascular Inflammation and Vascular Remodeling: A Common Cause of Hemorrhage in Cerebral Small Vessel Diseases?

Massachusetts General Hospital, Boston MA

Investigators

Abstract

Project Summary / Abstract Title project: “Perivascular inflammation and vascular remodeling: a common cause of hemorrhage in cerebral small vessel diseases?” Cerebral small vessel disease (CSVD) is a major contributor to intracerebral hemorrhage in the aging human brain. The two most common sporadic forms of CSVD are cerebral amyloid angiopathy (CAA) and arteriolosclerosis. By the time CSVD is diagnosed during life, the underlying small vessel pathology has already advanced to end-stage disease. There are currently no treatments that target the final steps leading up to vessel rupture and hemorrhage. This proposal builds on recent key observations from the applicant’s lab suggesting immune-mediated vascular remodeling and reduced β-amyloid in individual vessels associated with microhemorrhages in CAA. This project will test the overarching hypothesis that perivascular inflammation contributes to vascular remodeling, resulting in vessel rupture and hemorrhage in CAA. Understanding these fundamental pathophysiological mechanisms may uncover novel targets for much needed treatment strategies. This project will leverage well-characterized autopsy cases of patients with a neuropathologically confirmed diagnosis of CAA and other forms of sporadic and hereditary CSVD to determine shared pathways. The complementary use of quantitative neuropathology in human brain tissue samples with longitudinal in vivo two- photon microscopy in mouse models with CAA will allow studying the sequence of events leading up to vessel wall remodeling and hemorrhage in real-time. If successful, the outcomes of this project are expected to have high impact, because 1) the analyses are targeted at the disease stage present at the time CSVD is diagnosed, 2) inflammatory pathways have substantial likelihood to be ‘druggable’ (i.e. response to candidate intervention), and 3) since arteriolosclerosis also seems to entail a gradual loss of normal vessel wall components followed by remodeling and vessel rupture, there is high potential for the results of the CAA study to generalize to the other common CSVD.