Agarwal, Vijay

Abstract Introduction Glioblastoma (GBM), the most aggressive primary brain tumor in adults, is marked by profound immune suppression. Tumor-derived extracellular vesicles (TEVs) are increasingly recognized as key mediators of this immunosuppressive environment. Methods In this study, we examined the tumor-immune microenvironment using ultrasonic aspirate samples from GBM patients (n = 14). Results Several immune checkpoint molecules, including PDL1, B7-H3, and VISTA, were notably elevated. TIGIT, a receptor typically associated with T cells, was widely expressed across multiple myeloid subsets, including monocytic myeloid-derived suppressor cells (mMDSCs; 64.27±7.99%) and non-classical monocytes (NCM; 39.8±4.37%). Co-culture of healthy donor CD11b+ cells (n = 10) with TEVs replicated similar effects (mMDSCs; control 11.691.87 vs EV treated 23.322.0). We found CD155, a primary TIGIT ligand, to be heavily enriched in TEVs and co-localized with TIGIT in co-culture, suggesting the TIGIT/CD155 axis may be involved in promoting immune suppression. induced MDSCs markedly suppressed T cell proliferation (30.65 ± 5.97% vs. control 86.47 ± 2.94, p = 0.0001), accompanied by elevated Th2 cytokine production and increased NLRP3 and IL-1β expression. Interestingly, TIGIT knockdown did not affect NLRP3 expression, but did restore T cell proliferation (64.13±1.33%; p = 0.02) and pro-inflammatory cytokine production. However, this effect was lost upon NLRP3 knockdown, indicating its essential role in mediating immune rescue. Furthermore, IL-13 (a Th2 cytokine) blockade, in this model, enhanced pro-inflammatory response by suppressing phosphorylation of STAT-6 protein. Conclusion Overall, our findings highlight a crucial role for the TIGIT/CD155 axis in driving myeloid-mediated immune suppression in GBM. Furthermore, TIGIT inhibition may unmask NLRP3 function, potentially contributing to immune rescue. Funding Source Neurosurgery Research & Education Foundation through the B*CURED & NREF Young Clinician Investigator Award, as well as intramural K12 funding through the Institute for Clinical and Translational Research and the NCI Paul Calabresi Career Development Award (1K12CA279871). Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Abstract Glioblastoma (GBM), the most aggressive primary brain tumor in adults, is marked by profound immune suppression. Tumor-derived extracellular vesicles (TEVs) are increasingly recognized as key mediators of this immunosuppressive environment. In this study, we examined the tumor-immune microenvironment using ultrasonic aspirate samples from GBM patients (n = 14). Several immune checkpoint molecules, including PDL1, B7-H3, and VISTA, were notably elevated. TIGIT, a receptor typically associated with T cells, was widely expressed across multiple myeloid subsets, including monocytic myeloid-derived suppressor cells (mMDSCs; 64.27 ± 7.99%) and non-classical monocytes (NCM; 39.8 ± 4.37%). Co-culture of healthy donor monocytes (n=10) with TEVs replicated similar effects (control 11.69±1.87 vs EV treated 23.32±2.0). We found CD155, the primary TIGIT ligand, to be heavily enriched in TEVs and co-expressed with TIGIT in co-culture, suggesting the TIGIT/CD155 axis may be involved in promoting immune suppression. Additionally, induced MDSCs significantly inhibit T cell proliferation (30.65±5.97% proliferation, v/s control 86.47±2.94, p=0.0001), concomitant with a surge in Th2 immune responses via TIGIT+ monocytes along with an increase in NLRP3 and IL-1β expressing cells. Interestingly, TIGIT knockdown did not affect NLRP3 expression but did restore T cell proliferation (64.13 ± 1.33%; p = 0.02) and pro-inflammatory cytokine production. However, the restoration of T cell proliferation was lost when NLRP3 was also silenced, indicating its essential role in mediating immune rescue. Overall, our findings highlight a crucial role of TIGIT in driving myeloid-mediated immune suppression in GBM. Furthermore, TIGIT inhibition may unmask NLRP3 function, potentially contributing to immune rescue.

Abstract BackgroundOur study aims to fill the vacancy of litigation studies related to trigeminal neuralgia management, and to give healthcare providers the necessary information needed to better understand the potential litigious outcomes that often follow certain treatment methods.MethodsWe queried the Westlaw Edge legal database to identify litigation cases related to the management of trigeminal neuralgia for the years 1985-2019 using the following search criteria: (trigeminal & neuralgia), (tic & douloureux) and (microvascular & decompression). Key variables extracted included the following: plaintiff medical complaints, trial outcome, payout, and demographic characteristics. Continuous variables were compared between cases in favor of defendant and cases in favor of plaintiff using t-test or Wilcoxon rank sum test. Categorical variables were compared using chi-square or Fischer’s exact test.Results49 cases met the inclusion criteria – for those cases surgical complication (42.9%) and failure to diagnose (32.7%) were cited as the most common alleged reasons for filing a malpractice claim. Cranial nerve deficits (34.7%) and loss of consortium (12.2%) were the most frequent post-operative complaints. Verdicts ruled in favor of the defendant in 61.2% of cases, and for the plaintiff in 26.5% of cases with a mean payout of $1,982,428.46. Dental specialists were included in the most cases, 63.3%, and the average payout was $415,908, while Neurosurgical specialists were involved in 20.4% of cases with an average payout of $618,775. Cases where the verdict was in favor of the plaintiff were more likely to be older than cases with a verdict in favor of the defendant (p=0.03). ConclusionsOver one-half of the cases resulted in a defendant’s verdict with surgical complications cited as the most common reason for litigation. Dentistry and neurosurgery were listed as the most common individual physician specialties for defendants, also contributing to the largest average payouts based on specialty (for specialties > 1 occurrence). Cranial nerve deficits and loss of consortium were the most common plaintiff post-operative complaints. A key implication of this study is the need for more extensive discussions between physician and patient regarding informed consent, especially when neurosurgical interventions are required.