Smith, Alexander J.

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, with a dismal 5-year survival rate of ~6.5%. Vasogenic cerebral edema is a severe complication that occurs in the majority of GBM patients, leading to a significant increase in intracranial pressure, neurological deficits, and increased mortality rates. GBM-associated edema is almost exclusively managed by the corticosteroid dexamethasone, the use of which is associated with immunosuppression and interference with radiation therapy. While there is considerable research on edema formation, little is known about how edema resolution occurs in GBM, particularly in response to dexamethasone or other anti-edema therapies. This gap in understanding highlights the need for new approaches to treat edema effectively. The water channel aquaporin-4 (AQP4), a key player in the brain’s water homeostasis, is upregulated in GBM compared to the normal brain. To investigate the role of AQP4 in GBM-associated edema, we used the RCAS/tv-a system to generate de novo GBM with different driver mutations in Aqp4 knockout (KO) and wild-type (WT) mice. Our results indicated that Aqp4 KO tumor-bearing mice had shortened survival and increased edema content. Additionally, Aqp4 loss decreased astrocyte coverage specifically in the tumor core but not the tumor periphery. Our single cell RNA-seq data suggested that Aqp4 loss led to an astrocytic shift towards a less reactive, progenitor-like state, while also decreasing the myeloid and CD8+ T cell population in the tumor microenvironment. Interestingly, tumor-bearing mice treated with anti-VEGFA antibody, which has anti-edema properties, showed increased expression of Aqp4 and reduced vessel leakage. This suggests that AQP4 plays a critical role in mediating the effects of anti-VEGFA therapy. Overall, this study highlights the important role of AQP4 in the resolution of edema, while also revealing its additional effects on astrocyte activation and the immune microenvironment in GBM.

INTRODUCTION: Inflammatory Bowel Disease (IBD) is associated with a reduced quality of life, including a high incidence of poor sleep. Minority patients with IBD describe poorer subjective symptoms of disease. Minority patients are more likely to report poorer sleep quality compared to Caucasian patients. There are limited data on the assessment of sleep in minority patients with IBD. In this prospective cohort study, we aim to compare objective sleep parameters assessed by wrist actigraphy in minority IBD patients compared to Caucasian IBD patients. METHODS: 73 patients with a diagnosis of IBD were recruited to take part in this IRB approved study. Subjects were stratified into two cohorts by self-identification: minority subjects (Blacks and Non-Black Hispanic subjects) and Caucasian, non-minority individuals. Subjects were excluded based on significant co-morbidity, a history of a sleep disorder, or demographics which did not fit into categorized cohorts. Subjects completed sleep surveys and were provided with an accelerometer that estimated sleep patterns. Comparisons of actigraphic parameters were performed between minority and non-minority cohorts. Regression analyses were performed to determine whether minority status was independently associated with poorer sleep parameters assessed by actigraphy. Predictors that were found to be different by < 0.1 between cohorts were included in the models. RESULTS: Of the recruited subjects, 64 subjects completed 3 days of actigraphy data. 33 subjects were minority patients and 31 individuals were non-minority patients. The demographics of the cohorts are provided in Table 1. Table 2 details the univariate analyses. A higher proportion of minority patients had poorer sleep efficiency (SE) and fragmented sleep compared to Caucasian patients (90.9% vs. 67.7%, P = 0.03 and 87.8% vs. 61.3%, P = 0.02). Minority status was independently associated with both poor SE (OR: 6.41 CI: 1.48-28.17, P = 0.0139) and fragmented sleep (OR: 4.98, CI: 1.09-22.89, P = 0.0389), (Tables 3.0A and 3.0B). CONCLUSION: In our study minority subjects were found to have poorer objective measures of sleep assessed by actigraphy compared to non-minority subjects. Culturally relevant care addressing psychosocial issues, including sleep are important in the care of minority patients with IBD. Further studies investigating the role of sleep in diverse populations with IBD are warranted to determine the etiologies of poor sleep in these patients.