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Gillespie ER, Grice LF, Courtney IG, Lao HW, Jung W, Ramkomuth S, Xie J, Brown DA, Walsham J, Radford KJ, Nguyen QH, Ruitenberg MJ. Single-cell RNA sequencing reveals peripheral blood leukocyte responses to spinal cord injury in mice with humanised immune systems. J Neuroinflammation 2024; 21:63. [PMID: 38429643 PMCID: PMC10908016 DOI: 10.1186/s12974-024-03048-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 02/14/2024] [Indexed: 03/03/2024] Open
Abstract
Next-generation humanised mouse models and single-cell RNA sequencing (scRNAseq) approaches enable in-depth studies into human immune cell biology. Here we used NSG-SGM3 mice engrafted with human umbilical cord haematopoietic stem cells to investigate how human immune cells respond to and/or are changed by traumatic spinal cord injury (SCI). We hypothesised that the use of such mice could help advance our understanding of spinal cord injury-induced immune depression syndrome (SCI-IDS), and also how human leukocytes change as they migrate from the circulation into the lesion site. Our scRNAseq experiments, supplemented by flow cytometry, demonstrate the existence of up to 11 human immune cell (sub-) types and/or states across the blood and injured spinal cord (7 days post-SCI) of humanised NSG-SGM3 mice. Further comparisons of human immune cell transcriptomes between naïve, sham-operated and SCI mice identified a total of 579 differentially expressed genes, 190 of which were 'SCI-specific' (that is, genes regulated only in response to SCI but not sham surgery). Gene ontology analysis showed a prominent downregulation of immune cell function under SCI conditions, including for T cell receptor signalling and antigen presentation, confirming the presence of SCI-IDS and the transcriptional signature of human leukocytes in association with this phenomenon. We also highlight the activating influence of the local spinal cord lesion microenvironment by comparing the transcriptomes of circulating versus infiltrated human immune cells; those isolated from the lesion site were enriched for genes relating to both immune cell activity and function (e.g., oxidative phosphorylation, T cell proliferation and antigen presentation). We lastly applied an integrated bioinformatics approach to determine where immune responses in humanised NSG-SGM3 mice appear congruent to the native responses of human SCI patients, and where they diverge. Collectively, our study provides a valuable resource and methodological framework for the use of these mice in translational research.
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Affiliation(s)
- Ellen R Gillespie
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Laura F Grice
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Isabel G Courtney
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Hong Wa Lao
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Woncheol Jung
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Sonny Ramkomuth
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Jacky Xie
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - David A Brown
- Neuroinflammation Research Group, Centre for Immunology and Allergy Research, Westmead Institute for Medical Research, Sydney, Australia
- Centre for Immunology and Allergy Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia
- Institute for Clinical Pathology, New South Wales Health Pathology, Sydney, Australia
| | - James Walsham
- Intensive Care Unit, Princess Alexandra Hospital, Brisbane, Australia
- Medical School, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Kristen J Radford
- Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Australia
| | - Quan H Nguyen
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Marc J Ruitenberg
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4072, Australia.
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Dhillon NK, Adjamian N, Fierro NM, Conde G, Barmparas G, Ley EJ. Early Antibiotic Administration is Independently Associated with Improved Survival in Traumatic Brain Injury. J Surg Res 2021; 270:495-502. [PMID: 34808469 DOI: 10.1016/j.jss.2021.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 08/12/2021] [Accepted: 10/05/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Central and systemic immune dysfunction after traumatic brain injury (TBI) can lead to infectious-related complications, which may result in delayed mortality. The role of early empiric antibiotics after TBI has not been characterized to date, but is recommended in select cases to decrease complications. We aimed to determine the relationship between early antibiotic use and in-hospital mortality in TBI patients. METHODS A retrospective review was conducted of TBI patients requiring ICU admission at an urban, academic, Level I trauma center from 01/2014 to 08/2016. Data collection included demographics, injury characteristics, details regarding antibiotic use, and outcomes. Early antibiotic administration was defined as any antibiotic given within 48 hs from admission. Patients given early antibiotics (EARLY) were compared to those who received their first dose later or did not receive any antibiotics (non-EARLY). RESULTS Of the 488 TBI patients meeting inclusion criteria, 189 (38.7%) received early antibiotics. EARLY patients were younger (EARLY 54.2 versus non-EARLY 61.5 ys, P <0.01) and more likely to be male (71.4% versus 60.9%, P = 0.02). Injury severity scores (23.6 versus 17.2, P <0.01) and regional head abbreviated injury scale scores (3.9 versus 3.7, P <0.01) were significantly higher in patients who received early antibiotics. Unadjusted in-hospital mortality rates were similar, however EARLY was associated with a lower mortality rate (AOR 0.17, 95% CI: 0.07 - 0.43, adjusted P <0.01) after adjusting for confounders. CONCLUSIONS Despite presenting with a higher injury burden, TBI patients who received early antibiotics had a lower associated mortality rate compared to their counterparts. Future investigations are necessary to understand the underlying mechanisms that result in this potential survival benefit.
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Affiliation(s)
- Navpreet K Dhillon
- Department of Surgery, Division of Trauma and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California
| | - Norair Adjamian
- Department of Surgery, Community Memorial Health System, Ventura, California
| | - Nicole M Fierro
- Department of Surgery, Division of Trauma and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California
| | - Geena Conde
- Department of Surgery, Division of Trauma and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California
| | - Galinos Barmparas
- Department of Surgery, Division of Trauma and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California
| | - Eric J Ley
- Department of Surgery, Division of Trauma and Critical Care, Cedars-Sinai Medical Center, Los Angeles, California.
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Karakaya D, Cakir-Aktas C, Uzun S, Soylemezoglu F, Mut M. Tailored Therapeutic Doses of Dexmedetomidine in Evolving Neuroinflammation after Traumatic Brain Injury. Neurocrit Care 2021; 36:802-814. [PMID: 34782991 DOI: 10.1007/s12028-021-01381-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 10/13/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND Understanding the secondary damage mechanisms of traumatic brain injury (TBI) is essential for developing new therapeutic approaches. Neuroinflammation has a pivotal role in secondary brain injury after TBI. Activation of NLRP3 inflammasome complexes results in the secretion of proinflammatory mediators and, in addition, later in the response, microglial activation and migration of the peripheral immune cells into the injured brain are observed. Therefore, these components involved in the inflammatory process are becoming a new treatment target in TBI. Dexmedetomidine (Dex) is an effective drug, widely used over the past few years in neurocritical care units and during surgical operations for sedation and analgesia, and has anti-inflammatory effects, which are shown in in vivo studies. The aim of this original research is to discuss the anti-inflammatory effects of different Dex doses over time in TBI. METHODS Brain injury was performed by using a weight-drop model. Half an hour after the trauma, intraperitoneal saline was injected into the control groups and 40 and 200 μg/kg of Dex were given to the drug groups. Neurological evaluations were performed with the modified Neurological Severity Score before being killed. Then, the mice were killed on the first or the third day after TBI and histopathologic (hematoxylin-eosin) and immunofluorescent (Iba1, NLRP3, interleukin-1β, and CD3) findings of the brain tissues were examined. Nonparametric data were analyzed by using the Kruskal-Wallis test for multiple comparisons, and the Mann-Whitney U-test was done for comparing two groups. The results are presented as mean ± standard error of mean. RESULTS The results showed that low doses of Dex suppress NLRP3 and interleukin-1β in both terms. Additionally, high doses of Dex cause a remarkable decrease in the migration and motility of microglial cells and T cells in the late phase following TBI. Interestingly, the immune cells were influenced by only high-dose Dex in the late phase of TBI and it also improves neurologic outcome in the same period. CONCLUSIONS In the mice head trauma model, different doses of Dex attenuate neuroinflammation by suppressing distinct components of the neuroinflammatory process in a different timecourse that contributes to neurologic recovery. These results suggest that Dex may be an appropriate choice for sedation and analgesia in patients with TBI.
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Affiliation(s)
- Dicle Karakaya
- Faculty of Medicine, Department of Neurosurgery, Hacettepe University, Ankara, Turkey
| | - Canan Cakir-Aktas
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Sennur Uzun
- Faculty of Medicine, Department of Anesthesiology and Reanimation, Hacettepe University, Ankara, Turkey
| | - Figen Soylemezoglu
- Faculty of Medicine, Department of Pathology, Hacettepe University, Ankara, Turkey
| | - Melike Mut
- Faculty of Medicine, Department of Neurosurgery, Hacettepe University, Ankara, Turkey.
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