Faculty Bibliography

The outbreak of coronavirus disease 2019 (COVID-19) is an unprecedented global health crisis. Tissue and peripheral blood analysis indicate profound, aberrant myeloid cell activation, cytokine storm, and lymphopenia, with unknown immunopathological mechanisms. Spatiotemporal control of the quality and quantity of the antiviral immune responses involves synchronized cellular and molecular cascades and cross-talk between innate and adaptive immunity. Dysregulated responses in immunity, such as at the stages of immune sensing, alarming, polarization, and resolution, may contribute to disease pathology. Herein, we approach SARS-CoV-2 through an immunomodulatory lens, discussing possible mechanisms of the asynchronized antiviral immune response and proposing potential therapeutic strategies to correct the dysregulation.

The COVID-19 pandemic dramatically affected the operations of New York City hospitals during March and April of 2020. This article describes the transformation of a neurology division at a 450-bed tertiary care hospital in a multi-ethnic community in Brooklyn during this initial wave of COVID-19. In lieu of a mass redeployment of staff to internal medicine teams, we report a novel method for a neurology division to participate in a hospital's expansion of care for patients with COVID-19 while maintaining existing team structures and their inherent supervisory and interpersonal support mechanisms.

Cytokines were the first modern immunotherapies to produce durable responses in patients with advanced cancer, but they have only modest efficacy and limited tolerability^1,2. In an effort to identify alternative cytokine pathways for immunotherapy, we found that components of the interleukin-18 (IL-18) pathway are upregulated on tumour-infiltrating lymphocytes, suggesting that IL-18 therapy could enhance anti-tumour immunity. However, recombinant IL-18 previously did not demonstrate efficacy in clinical trials³. Here we show that IL-18BP, a high-affinity IL-18 decoy receptor, is frequently upregulated in diverse human and mouse tumours and limits the anti-tumour activity of IL-18 in mice. Using directed evolution, we engineered a 'decoy-resistant' IL-18 (DR-18) that maintains signalling potential but is impervious to inhibition by IL-18BP. Unlike wild-type IL-18, DR-18 exerted potent anti-tumour effects in mouse tumour models by promoting the development of poly-functional effector CD8⁺ T cells, decreasing the prevalence of exhausted CD8⁺ T cells that express the transcriptional regulator of exhaustion TOX, and expanding the pool of stem-like TCF1⁺ precursor CD8⁺ T cells. DR-18 also enhanced the activity and maturation of natural killer cells to effectively treat anti-PD-1 resistant tumours that have lost surface expression of major histocompatibility complex class I molecules. These results highlight the potential of the IL-18 pathway for immunotherapeutic intervention and implicate IL-18BP as a major therapeutic barrier.

Objective: To describe the ischemic stroke subtypes related to coronavirus disease 2019 (COVID-19) in a cohort of New York City hospitals and explore their etiopathogenesis. Background: Most neurological manifestations are non-focal, but few have reported the characteristics of ischemic strokes or investigated its pathophysiology. Methods: Data were collected prospectively April 1-April 15, 2020 from two centers in New York City to review possible ischemic stroke types seen in COVID-19-positive patients. Patient presentation, demographics, related vascular risk factors, associated laboratory markers, as well as imaging and outcomes were collected. Results: The age of patients ranged between 27 and 82 years. Approximately 81% of patients had known vascular risk factors, the commonest being hypertension (75%) followed by diabetes (50%) coronary disease or atrial fibrillation. Eight patients presented with large vessel occlusion (LVO) with median age 55 years (27-82) and all were male. Eight patients presented with non-LVO syndromes, with median age 65.5 years (59-82) and most were female (62.5%). Both groups were 50% African Americans and 37.5% South Asian. Both groups had similar D-dimer levels although other acute phase reactants/disease severity markers (Ferritin, CRP, procalcitonin) were higher in the LVO group. The LVO group also had a significantly higher mortality compared to the non-LVO group. The most common etiology was cryptogenic (6 patients) followed by small vessel occlusion (3 patients) and undetermined-unclassified (3 patients). For the remaining 4 patients, 2 were identified as cardioembolic and 2 with large artery atherosclerosis. Conclusion: COVID-19-related ischemic events can present as small vessel occlusions, branch emboli or large vessel occlusions. The most common etiology is cryptogenic. Patients with LVO syndromes tend to be younger, male and may have elevated acute inflammatory markers.

To identify the factors mediating the progression of diabetic nephropathy (DN), we performed RNA sequencing of kidney biopsy samples from patients with early DN, advanced DN, and normal kidney tissue from nephrectomy samples. A set of genes that were upregulated at early but downregulated in late DN were shown to be largely renoprotective, which included genes in the retinoic acid pathway and glucagon-like peptide 1 receptor. Another group of genes that were downregulated at early but highly upregulated in advanced DN consisted mostly of genes associated with kidney disease pathogenesis, such as those related to immune response and fibrosis. Correlation with estimated glomerular filtration rate (eGFR) identified genes in the pathways of iron transport and cell differentiation to be positively associated with eGFR, while those in the immune response and fibrosis pathways were negatively associated. Correlation with various histopathological features also identified the association with the distinct gene ontological pathways. Deconvolution analysis of the RNA sequencing data set indicated a significant increase in monocytes, fibroblasts, and myofibroblasts in advanced DN kidneys. Our study thus provides potential molecular mechanisms for DN progression and association of differential gene expression with the functional and structural changes observed in patients with early and advanced DN.

PURPOSE OF REVIEW/OBJECTIVE:A major goal in neurocritical care is to monitor for and prevent secondary brain injuries. However, injuries occurring at the cellular and molecular levels evade detection by conventional hemodynamic monitoring and the neurological exam. Cerebral microdialysis (CMD) is an invasive means of providing nearly continuous measurements of cerebral metabolism and is a promising tool that can detect signs of cellular distress before systemic manifestations of intracranial catastrophe. RECENT FINDINGS/RESULTS:In this review, we describe the technique of CMD and the common biomarkers used to monitor cerebral energy metabolism. We examine the published evidence on how CMD data reflect secondary injuries and improve understanding of the pathophysiology of traumatic brain injury (TBI) and aneurysmal subarachnoid hemorrhage. We also discuss some of the caveats of the technique, including how CMD probe position affect the sensitivity of capturing energy failures, and how abnormal levels of cerebral glucose and lactate can reflect different states of cerebral energy metabolism. In order to best incorporate cerebral metabolic monitoring into the management of neurocritical care patients, neurointensivists must be familiar with the nuances in the limitations as well as the interpretations of data obtained from cerebral microdialysis.