Identification of Novel Molecular Markers for Vasospasm

Cerebral vasospasm is a recognized and poorly understood complication for many patients who have aneurysmal subarachnoid hemorrhage. Constriction of the cerebral arterial vasculature occurs as free subarachnoid blood under high pressure comes into contact with the surfaces of vessels, particularly in the basal cisterns. However, the exact pathophysiology of vasospasm is unknown. Morbidity and mortality rates for vasospasm are high despite improvements in management. Excluding the initial hemorrhage, cerebral vasospasm is recognized as the main cause of substantial disability and death. Cerebral vasospasm kills 7% of patients, and causes severe deficit in another 7%. Cerebral vasospasm almost never occurs before day 3, has maximal incidence at days 6-8, and rarely occurs after day 17. The disorder is clinically characterized by confusion or decreased consciousness with focal neurological deficit. Experimental evidence suggests that red blood cell hemolysis and subsequent release of oxygen, hemoglobin, reactive oxygen species, and other as yet undescribed mediators are necessary for the development of vasospasm. The goal of this study is to use modern tools of genomics to identify novel molecular markers for the process of vasospasm by studying the release of micro ribonucleic acids (RNA) that are secreted into the cerebrospinal fluid following the initiation of vasospastic cascades. Micro RNA's have recently been identified as important regulators of many cellular processes including cell cycle progression, proliferation, tumor suppressors, oncogenes, and regulators of metabolic pathways. The researchers propose to study the levels of annotated micro RNA's in the cerebrospinal fluid (CSF) of patients who present with subarachnoid hemorrhage from presentation through the hospital stay. The researchers will correlate the level of these micro RNA's with patient clinical presentation, including transcranial Doppler measurements, Glasgow Coma Scale score, vital signs, and angiographic studies. It is well established that the process of vasospasm occurs over the course of many days. Long before vasospasm becomes clinically evident, cellular processes causing spasm are in action and the researchers hope to identify micro RNA mediators of these processes using high throughput screening methods.