Cavernous angiomas (CA) are common vascular anomalies causing brain hemorrhage. Based on mouse studies, roles of gram-negative bacteria and altered intestinal homeostasis have been implicated in CA pathogenesis, and pilot study had suggested potential microbiome differences between non-CA and CA individuals based on 16S rRNA gene sequencing. We here assess microbiome differences in a larger cohort of human subjects with and without CA, and among subjects with different clinical features, and conduct more definitive microbial analyses using metagenomic shotgun sequencing. Relative abundance of distinct bacterial species in CA patients is shown, consistent with postulated permissive microbiome driving CA lesion genesis via lipopolysaccharide signaling, in humans as in mice. Other microbiome differences are related to CA clinical behavior. Weighted combinations of microbiome signatures and plasma inflammatory biomarkers enhance associations with disease severity and hemorrhage. This is the first demonstration of a sensitive and specific diagnostic microbiome in a human neurovascular disease.

clinicaltrials.gov Identifier: NCT00094575.

Background: Patient-reported quality of life (QoL) using standardized tools have been proposed as outcome measures in clinical trials. The NeuroQoL scale has been evaluated in patients with common neurological disorders (e.g., ischemic stroke, epilepsy, ALS, and Parkinson’s), but has not been applied to familial cerebral cavernous malformation (FCCM). FCCM is typically characterized by multiple brain lesions that can cause clinical symptoms (hemorrhages, seizures, headaches, neurological deficits) and affect QoL. The purpose of this study was to summarize NeuroQoL domain scores in FCCM patients. Methods: NeuroQoL short forms covering 12 QoL domains (Figure) were completed by 50 FCCM adults enrolled in the Brain Vascular Malformation Consortium CCM Project. Raw scores summing responses in each domain were converted to T-scores, which are standardized to general (8 domains) or clinical (4 domains) reference populations with mean of 50 and standard deviation of 10. One-sample t-tests were used to determine whether mean T-scores were significantly different from 50 (p<0.05). Results: We observed significant differences between FCCM and the reference populations on several domains (Figure). Compared to the general reference population, FCCM patients were more likely to have higher positive affect (56, p<0.001) and less depression (55, p<0.001), but lower social satisfaction (48, p=0.032). Compared to the clinical reference population, FCCM patients reported significantly less stigma (61, p<0.001) and less fatigue (54, p=0.018). Conclusion: FCCM patients differed from the reference populations on several NeuroQoL domains, including positive affect, depression, stigma, fatigue and social satisfaction. Further studies are needed to understand the effect of clinical symptoms on NeuroQoL domains in FCCM.

Background: Cerebral cavernous malformation (CCM) patients have lesions comprised of dilated capillaries in the brain. Despite the knowledge that mutations of three CCM genes can cause this disease, other genetic and environmental factors that contribute to lesion formation are likely given the highly variable disease expression. Genome-wide association studies in CCM cohorts and mouse models of CCM, both point to a role of lipopolysaccharide. Mouse studies have shown that the microbiome, particularly Gram-negative bacteria, drive CCM lesion development. These data point to a possibility that CCM disease is affected by the gut microbiome. In this study, we investigated if human CCM disease could be linked to the gut microbiome. Methods: Fecal samples from 88 CCM patients, from four sites, were assayed using 16S rRNA gene sequencing. Following taxonomic classification by exact sequence variant analysis (ESV) using DeBlur, microbiome composition was compared with those of a reference non-CCM population (n=348), or between subgroups of CCM patients based on clinical data elements. Results: Analyses of microbiome composition statistics identified bacterial ESVs belonging to Clostridiales , Lachnospiraceae, Ruminococcaceae , and the genus Bacteroides that were significantly enriched in CCM patients compared to healthy controls. Within our CCM cohort, patients with germline CCM mutations had stool-associated enrichment of ESVs annotated to Clostridiales, and the genera Bacteroides and Prevotella , when compared to sporadic CCM patients, while patients with CCM1 and CCM2 mutations had different proportions of Clostridiales, Lachnospiraceae, and the genus Ruminococcus . Furthermore, Lachnospiraceae and Bacteroides proportions differentiated disease aggressiveness (All p<0.05, false discovery rate corrected). Conclusions: These data are the first to show that CCM patients have a distinct microbiome signature. Germline mutation and disease aggressiveness can correlate with further unique microbiome composition. This study supports further investigation into the mechanistic link between CCM disease and the microbiome. This will enhance our understanding of the brain-gut axis in CCM disease and the use of microbiome as a therapeutic target.