Abstract WP17: Plasma Proteins In Correlation With Lesional Iron Content And Permeability Imaging In Clinical Trial Of Cavernous Angioma With Symptomatic Hemorrhage

Background: Increases in mean lesional iron content (≥6%) measurement by QSM and vascular permeability (≥40%) assessed by DCEQP MRI have been associated with new bleeding, and are used as monitoring biomarkers in NINDS funded 1st clinical trial of pharmacotherapy (clinicaltrials.gov NCT02603328) in cavernous angiomas with symptomatic hemorrhage (CASH). Plasma protein levels previously associated with CASH in diagnostic and prognostic contexts have never been compared to lesional QSM and DCEQP in the same subjects. Methods: Plasma samples and MRI sequences were simultaneously acquired during 1 year-epochs of prospective follow-up of CASH patients. Plasma levels of 16 proteins were assayed by ELISA and correlated with lesional QSM and DCEQP during the same epochs. Univariate correlations were followed by multivariate analyses combining multiple protein levels to minimize Akaike Information Criterion (AIC) and increase R 2 . Accuracy (AUC on receiver operating curves) and sum of squared error (SSE) are reported for associations achieving statistical significance with FDR correction. Results: None of the proteins individually correlated with QSM/DCEQP (continuous or categorical). Relative change of angiopoietin2, and absolute change of the combination (endoglin+IL1B+IL16) had the highest accuracy (AUC 78.7%, SD 0.062 and 98.4%, SD 0.013 respectively) for lesional QSM increase ≥6%. Relative change of endoglin+IL1B, and absolute change of angiopoetin2+endoglin+thromobomodulin+VEGF, had the highest accuracy (AUC 64.6%, SD 0.057 and 93.2%, SD 0.040 respectively) for lesional DCEQP increase ≥40%. Relative change in angiopoetin1 had the lowest SSE (8.87) with QSM change as a continuous variable, and relative change in lipopolysaccharide binding protein had the lowest SSE (469.06) with DCEQP change as continuous variable. Conclusion: Circulating proteins reflect changes in lesional iron content and permeability in CASH during prospective follow-up. Results are a proof of concept that blood tests could replace more complex and costly imaging biomarkers in the monitoring of hemorrhage in cavernous angiomas. Additional mechanistic plasma molecules (miRNAs and metabolites) may further enhance the accuracy of these monitoring biomarkers.