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Hypothermia increases mortality rates and should be treated aggressively in the forward echelons of care, but no practical solution exists to accomplish such treatment. The enormous energy burden for this task requires maximal thermodynamic efficiency for a practical portable solution. This review article presents an overview of the clinical and thermodynamic challenges related to the development of a successful system for treatment of hypothermia in the forward echelons. Specific issues addressed include (1) the clinical and logistical reasons why thermal resuscitation should be attempted at all in such a difficult environment, (2) the thermodynamic reasons why warm intravenous fluids, although helpful in not worsening hypothermia, cannot safely transmit enough energy to treat established hypothermia, (3) which among the various methods of rewarming are most likely to result in successful therapy, and (4) the energetic considerations that dictate that any practical portable solution to the treatment of hypothermia must use hydrocarbon combustion as the source of heat. [ABSTRACT FROM AUTHOR]

Recently, it has been well-established that the glymphatic or glial-lymphatic system plays a vital role in the pathophysiology of various neurological compromise, especially hydrocephalus (HCP). Till now, the complete pathway is not yet fully understood, and little evidence is available from the literature that links hydrocephalus to disorders of the glymphatic system. Most published molecular studies and animal research have shown that, in models with hydrocephalus, the drainage of cerebrospinal fluid (CSF) via the glymphatic system is disrupted. This is strongly observed in normal pressure and post-hemorrhagic hydrocephalus cases. A thorough search of the literature to date yields scarce evidence on studies conducted on humans. Despite major similarities between non-human and human glymphatic pathways, the need for studies conducted on humans is becoming more urgent as the glymphatic pathway has been shown to be a good candidate for therapeutic intervention. In this review, we collect and report the most updated evidence addressing the glymphatic drainage pathways and their associations with the development of various types of hydrocephalus. In addition, we reveal the current scientific gap in human studies and our recommendations for the conduction of future clinical studies., Competing Interests: Declarations. Conflict of Interest: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Abstract: The variant single nucleotide polymorphism rs8104571 has been associated with poor outcomes following traumatic brain injury (TBI) and is most prevalent in those of African ancestry. This single nucleotide polymorphism (SNP) resides within a gene coding for the TRPM4 protein, which complexes with SUR1 protein to create a transmembrane ion channel and is believed to contribute to cellular swelling and cell death in neurological tissue. Our study evaluates the relationship between circulating TRPM4 and SUR1, rs8104571 genotype, and clinical outcome in TBI patients. Trauma patients with moderate to severe TBI were included in this retrospective study. rs8104571 genotyping and admission plasma TRPM4 and SUR1 quantification were performed with real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Adequate plasma for TRPM4 and SUR1 ELISA quantification was available for 289 patients, 54 of whom were African American (AA). Plasma TRPM4 concentration was increased in those with a variant rs8104571 allele compared with wild type when controlling for demographics and injury characteristics in the overall cohort ( P = 0.04) and within the AA subgroup ( P = 0.01). There was no significant association between plasma TRPM4 or SUR1 and clinical outcome (each P > 0.05). Plasma TRPM4 abundance increased with acute kidney injury severity ( P = 0.02). The association between increased plasma TRPM4 and variant rs810457 supports an underlying mechanism involving increased neuroinflammation with a subsequent increase in the leakage of TRPM4 from the central nervous system into circulation. Alternative sources of plasma TRPM4 including the kidney cannot be excluded and may play a significant role in the pathophysiology of trauma as well., Competing Interests: This research was supported by the National Institute of General Medical Sciences of the National Institutes of Health (T32GM008792). Additional funding was provided by the William Stamps Farish Fund, the Howell Family Foundation, and the James H. “Red” Duke Professorship. Dr. Cox reports additional support from the National Institutes of Health; Department of Defense-Medical Technology Enterprise Consortium; State of Texas Emerging Technology Fund; Generate Life Sciences, Inc.; Athersys, Inc.; Celgene Cellular Therapeutics; Cellvation, Inc.; Cellularity, Inc.; Hope Biosciences, Inc.; The Bentsen Foundation; Mission Connect; Let's Cure CP; Ladybug Foundation; Evelyn Griffin Foundation; Glassell Family Foundation; The George and Cynthia Mitchell Foundation; Grace R. Walls Endowment; Brown Foundation; Cellvation, Inc.; Coagulex, Inc.; and EMIT Corporation. No other authors report funding or conflicts of interest., (Copyright © 2024 by the Shock Society.)

As of 2020, penetrating injuries became the leading cause of death among children and adolescents ages 1-19 in the United States. For those patients who survive and receive advanced medical care, vascular injuries are a significant cause of morbidity and trigger notable trauma team angst. Moreover, penetrating injuries can lead to life-threatening hemorrhage and/or limb-threatening ischemia if not addressed promptly. Vascular injury management demands timely and unique expertise, particularly for pediatric patients. In part 1 of this review, we discussed the scope and extent of the epidemic of traumatic vascular injuries in pediatric patients, reviewed current evidence and outcomes, discussed various challenges and advantages of a myriad of existing team structures, and outlined potential outcome targets and solutions. However, in order to optimize care for pediatric vascular trauma, we must also understand the fundamental best practice principles, surgical options and approaches, medical management, and recommendations for ongoing, outpatient follow-up. In part 2, we will address the best evidence, combined with expert consensus, regarding strategies for diagnosing, managing, and ongoing follow-up of vascular trauma, with particular focus on the nuances that define the unique approaches to pediatric patients. LEVEL OF EVIDENCE: n/a., Competing Interests: Conflict of interest Authors have no relevant financial conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

As of 2020, penetrating injuries became the leading cause of death among children and adolescents ages 1-19 in the United States. For the patients who initially survive and receive advanced medical care, vascular injuries are a significant cause of morbidity and additionally trigger notable trauma team angst. Moreover, penetrating injuries can lead to life-threatening hemorrhage and/or limb-threatening ischemia if not addressed promptly. Vascular injury management demands timely and unique expertise, particularly for pediatric patients. As the frequency of vascular injuries requiring operative management increases, it becomes clear that an ad hoc approach is not ideal. An integrated team would provide the best approach for rapid hemorrhage control and revascularization, but the structure of vascular response teams at children's hospitals is highly variable. In part 1 of this review, we will evaluate the scope and extent of the epidemic of traumatic vascular injuries in pediatric patients, review current evidence and outcomes, discuss various challenges and advantages of different team structures, and outline potential outcome targets and pediatric vascular trauma response solutions. LEVEL OF EVIDENCE: n/a., Competing Interests: Conflicts of interest Authors have no relevant financial conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Autologous bone marrow mononuclear cells (BMMNCs) infused after severe traumatic brain injury have shown promise for treating the injury. We evaluated their impact in children, particularly their hypothesized ability to preserve the blood-brain barrier and diminish neuroinflammation, leading to structural CNS preservation with improved outcomes. We performed a randomized, double-blind, placebo-sham-controlled Bayesian dose-escalation clinical trial at two children's hospitals in Houston, TX and Phoenix, AZ, USA (NCT01851083). Patients 5-17 years of age with severe traumatic brain injury (Glasgow Coma Scale score ≤ 8) were randomized to BMMNC or placebo (3:2). Bone marrow harvest, cell isolation and infusion were completed by 48 h post-injury. A Bayesian continuous reassessment method was used with cohorts of size 3 in the BMMNC group to choose the safest between two doses. Primary end points were quantitative brain volumes using MRI and microstructural integrity of the corpus callosum (diffusivity and oedema measurements) at 6 months and 12 months. Long-term functional outcomes and ventilator days, intracranial pressure monitoring days, intensive care unit days and therapeutic intensity measures were compared between groups. Forty-seven patients were randomized, with 37 completing 1-year follow-up (23 BMMNC, 14 placebo). BMMNC treatment was associated with an almost 3-day (23%) reduction in ventilator days, 1-day (16%) reduction in intracranial pressure monitoring days and 3-day (14%) reduction in intensive care unit (ICU) days. White matter volume at 1 year in the BMMNC group was significantly preserved compared to placebo [decrease of 19 891 versus 40 491, respectively; mean difference of -20 600, 95% confidence interval (CI): -35 868 to -5332; P = 0.01], and the number of corpus callosum streamlines was reduced more in placebo than BMMNC, supporting evidence of preserved corpus callosum connectivity in the treated groups (-431 streamlines placebo versus -37 streamlines BMMNC; mean difference of -394, 95% CI: -803 to 15; P = 0.055), but this did not reach statistical significance due to high variability. We conclude that autologous BMMNC infusion in children within 48 h after severe traumatic brain injury is safe and feasible. Our data show that BMMNC infusion led to: (i) shorter intensive care duration and decreased ICU intensity; (ii) white matter structural preservation; and (iii) enhanced corpus callosum connectivity and improved microstructural metrics., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Introduction: Traumatic brain injury (TBI) is a leading cause of death and morbidity in the trauma population. Microglia drive the secondary neuroinflammatory response after TBI. We sought to determine if the microglial response to neurologic injury was exacerbated by a second stimulus after exposure to neurologic injury., Methods: Sprague-Dawley rats (age 2-3 wk) were divided into injured and noninjured groups. Injured rats underwent a controlled cortical impact injury; noninjured rats remained naïve to any injury and served as the control group. Primary rat microglia were isolated and applied to in vitro cultures. After incubation for 24 h, the microglia were stimulated with lipopolysaccharide (LPS) or norepinephrine. Twenty-four hours after stimulation, cell culture supernatant was collected. Tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) production were measured by standard enzyme-linked immunosorbent assays. GraphPad Prism was used for statistical analysis., Results: When compared to noninjured microglia, LPS induced a significantly greater production of TNF-α in microglia isolated from the injured ipsilateral (versus noninjured = 938.8 ± 155.1, P < 0.0001) and injured contralateral hemispheres (versus noninjured = 426.6 ± 155.1, P < 0.0001). When compared to microglia from noninjured cerebral tissue, IL-6 production was significantly greater after LPS stimulation in the injured ipsilateral hemisphere (mean difference versus noninjured = 9540 ± 3016, P = 0.0101) and the contralateral hemisphere (16,700 ± 3016, P < 0.0001). Norepinephrine did not have a significant effect on IL-6 or TNF-α production., Conclusions: LPS stimulation may amplify the release of proinflammatory cytokines from postinjury microglia. These data suggest that post-TBI complications, like sepsis, may propagate neuroinflammation by augmenting the proinflammatory response of microglia., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background Aims: Mesenchymal stromal cells (MSCs) are multipotent adult cells that can be isolated from tissues including bone marrow [MSC(BM)], adipose [MSC(AT)] and umbilical cord [MSC(CT)]. Previous studies have linked expression of tissue factor (TF) on MSC surfaces to a procoagulant effect. Venous thromboembolism (VTE), immediate blood-mediated inflammatory reaction (IBMIR) and microvascular thrombosis remain a risk with intravascular MSC therapy. We examined the effect of low molecular weight heparin (LMWH) on clinical-grade MSCs using calibrated automated thrombography (CAT)., Methods: Clinical grade MSC(BM)s, MSC(AT)s and MSC(CT)s harvested at passage 4 were added to normal pooled plasma (NPP) to a final concentration of either 400 000 or 50 000 cells/mL. LMWH was added to plasma in increments of 0.1 U/mL. Thrombin generation (TG) was measured using CAT. Flow cytometry was conducted on the cells to measure MSC phenotype and TF load., Results: Presence of MSCs decreased lag time and increased peak TG. All cell lines demonstrated a dose response to LMWH, with MSC(AT) demonstrating the least thrombogenicity and most sensitivity to LMWH. TG was significantly reduced in all cell lines at doses of 0.2 U/mL LMWH and higher., Discussion: All MSC types and concentrations had a decrease in peak thrombin and TG with increasing amounts of LMWH. While this in vitro study cannot determine optimal dosing, it suggests that LMWH can be effectively used to lower the risk of VTE associated with intravascular administration of MSCs. Future in vivo work can be done to determine optimal dosing and effect on IBMIR and VTE., Competing Interests: Declaration of Competing Interest/Funding CSC has the following relationships to disclose: he has existing or previous sponsored research agreements with CBR Systems, Inc. and has served on CBR’s Scientific & Medical Advisory Board, as well as on Biostage, Inc./Harvard Apparatus Regenerative Technology, Inc.’s Scientific Advisory Board. BSG has the following relationships to disclose: Coagulex, Inc.: Sponsored Research Funding and Equity/Royalty (interest via UTHealth). UTHealth has an institutional COI for holding equity in Coagulex. JCC has funding from the Department of Defense, Aniara, and has received speaker honoraria and research funding from Grifols. SDO is supported by NINDS R21NS116302. FT and SDO have existing or previous sponsored research agreements with Biostage, Inc./Harvard Apparatus Regenerative Technology, Inc., and CBR Systems, Inc. JBS was supported by a T32 fellowship from the National Institute of General Medical Sciences of the National Institutes of Health under award number 2T32GM008792. Manufacturing of MSC(AT)s and corresponding validation was funded by FT’s and SDO’s Sponsored Research Agreements with Biostage, Inc. The manufacturing and validation of MSC(CT)s were funded by a Sponsored Research Agreements with CBR Systems, Inc. in which CSC is the primary investigator and FT and SDO are coinvestigators., (Copyright © 2023 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Declaration of interests We declare no competing interests.

Introduction: Citrate-phosphate-dextrose (CPD) is the most common anticoagulant for blood product storage in the United States. It was developed to prolong shelf life, though there is little research regarding its impact on function following transfusion. We used flow cytometry (FC), thromboelastography (TEG), and a clot contraction assay called the zFlex platform to measure platelet activation and global clot formation in blood samples anticoagulated with either CPD or in a standard blue top citrate (BTC) tube., Methods: Samples were obtained through venipuncture of the antecubital fossa from healthy donors who had not recently taken antiplatelet medication. Samples for FC analysis were spun to obtain platelet-rich plasma, while TEG and zFlex utilized recalcified whole blood., Results: Mean fluorescence intensity for CD62p (P-selectin, marker of platelet activation) in baseline samples was equal, while mean fluorescence intensity in samples activated with thrombin receptor activating peptide was higher in CPD than BTC (65,814 ± 4445 versus 52,483 ± 5435, P = 0.007). TEG results demonstrated similar maximum amplitude for CPD (62.7 ± 1.8 mm versus 61 ± 1 mm) (P = 0.33), though reaction time and kinetics time were significantly longer in CPD versus BTC. CPD R-time: 7.9 ± 0.4 min versus BTC: 3.8 ± 0.4 (P < 0.001). CPD K-time: 2.2 ± 0.2 min versus BTC: 1.6 ± 0.1 min (P < 0.001). Clot contraction strength was not different between the two groups on zFlex: CPD 4353 ± 6 = 517 μN versus BTC 4901 ± 390 μN (P = 0.39)., Conclusions: Our findings suggest that CPD does not affect platelet function (minimal difference on FC and no difference in ultimate clot strength, which is ∼80% due to platelet function) but may alter clot dynamics by attenuating thrombin generation., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: A reduction in clot strength is a hallmark feature of trauma-induced coagulopathy. A better understanding of clot integrity can optimize resuscitation strategies. We designed a device to gauge clot strength by pressurizing fluids over a formed clot and measuring the pressure needed to dislodge the clot. We hypothesized that this device could distinguish between clots formed in hypocoagulable and hypercoagulable states by observing differences in the clot burst pressure., Methods: Whole blood from healthy volunteers was collected into sodium citrate tubes and was treated with heparin or fibrinogen to generate clots in a hypocoagulable or hypercoagulable state, respectively. Small bore holes were drilled into polystyrene plates, and recalcified blood was pipetted into the holes. Plates were incubated at 37°C for 30 min to form clots. A pressure cap with an inlet for fluid from a syringe pump and an outlet leading to a measurement column was secured in the wells with a watertight seal., Results: Clot burst pressure was normalized to individual baseline values to account for inherent differences in clot strength. The 1.0 g/L and 2.0 g/L fibrinogen groups were 1.65 ± 0.07 (P = 0.0078) and 2.26 ± 0.16 (P = 0.0078) times as strong as baseline, respectively. The 0.10, 0.15, or 0.20 USP units/mL groups were 0.388 ± 0.07 (P = 0.125), 0.31 ± 0.07 (P = 0.125), 0.21 ± 0.07 (P = 0.125) times as strong as baseline, respectively. Data were analyzed using Wilcoxon matched pairs signed rank testing., Conclusions: This device tests clot strength using burst pressure, an easily interpreted clinical parameter not measured in existing devices. Future work can test blood from trauma patients to better understand trauma pathophysiology., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Traumatic brain injury (TBI) results in activated microglia. Activated microglia can be measured in vivo by using positron emission topography (PET) ligand peripheral benzodiazepine receptor standardized uptake values (PBR28suv). Cell based therapies have utilized autologous bone marrow mononuclear cells (BMMNCs) to attenuate activated microglia after TBI. This study aims to utilize in vivo PBR28suv to assess the efficacy of BMMNCs therapy after TBI. Seventy-two hours after CCI injury, BMMNCs were harvested from the tibia and injected via tail-vein at 74 h after injury at a concentration of 2 million cells per kilogram of body weight. There were three groups of rats: Sham, CCI-alone and CCI-BMMNCs (AUTO). One hundred twenty days after injury, rodents were imaged with PBR28 and their cognitive behavior assessed utilizing the Morris Water Maze. Subsequent ex vivo analysis included brain volume and immunohistochemistry. BMMNCs therapy attenuated PBR28suv in comparison to CCI alone and it improved spatial learning as measured by the Morris Water Maze. Ex vivo analysis demonstrated preservation of brain volume, a decrease in amoeboid-shaped microglia in the dentate gyrus and an increase in the ratio of ramified to amoeboid microglia in the thalamus. PBR28suv is a viable option to measure efficacy of BMMNCs therapy after TBI., (© 2023. Springer Nature Limited.)

The Blood-Brain Barrier (BBB) is a highly-selective physiologic barrier responsible for maintaining cerebral homeostasis. Innovative in vitro models of the BBB are needed to provide useful insights into BBB function with CNS disorders like traumatic brain injury (TBI). TBI is a multidimensional and highly complex pathophysiological condition that requires intrinsic models to elucidate its mechanisms. Current models either lack fluidic shear stress, or neglect hemodynamic parameters important in recapitulating the human in vivo BBB phenotype. To address these limitations in the field, we developed a fluid dynamic novel platform which closely mimics these parameters. To validate our platform, Matrigel-coated Transwells were seeded with brain microvascular endothelial cells, both with and without co-cultured primary human astrocytes and bone-marrow mesenchymal stem cells. In this article we characterized BBB functional properties such as TEER and paracellular permeability. Our platform demonstrated physiologic relevant decreases in TEER in response to an ischemic environment, while directly measuring barrier fluid fluctuation. These recordings were followed with recovery, implying stability of the model. We also demonstrate that our dynamic platform is responsive to inflammatory and metabolic cues with resultant permeability coefficients. These results indicate that this novel dynamic platform will be a valuable tool for evaluating the recapitulating BBB function in vitro, screening potential novel therapeutics, and establishing a relevant paradigm to evaluate the pathophysiology of TBI., (© 2023. Springer Nature Limited.)

Background: Inflammation and white matter injury are consequences of neonatal intraventricular hemorrhage (IVH). Both white matter and the neuroimmune system are developing during the time which IVH occurs and its consequences develop. IVH has been studied in many different animal models; however, the effects of IVH occurring at different developmental time points in the same model have not been examined. Understanding how the timing of IVH affects outcome may provide important insights into both IVH pathophysiology and innate immune development., Methods: We used intraventricular injection of lysed whole blood to model neonatal IVH in postnatal day (P)2 and P5 rats. Flow cytometry was used to detect innate immune activation. MRI was used to screen animals for the development of increased ventricular size. Immunohistochemistry for myelin basic protein was used to quantify white matter and corpus callosum thickness., Results: P5 animals exhibited significant increases in several measures of classically pro-inflammatory innate immune activation that P2 animals did not. Animals with IVH induced at P5 also developed ventricular enlargement visible on MRI whereas animals with IVH induced at P2 did not. On histological analysis, there were no significant effects of IVH in P2 animals, but IVH in P5 animals reduced white matter labeling and corpus callosum thickness., Conclusions: IVH induces a strong innate inflammatory response in P5 as well as changes in ventricular size and reduction of white matter. P2 animals do not exhibit significant changes in innate immune activation or white matter structure after IVH. This suggests that white matter pathology from IVH is due in part to innate immune activation; and that the developmental stage of the innate immune system is a key determinant of IVH pathology., Competing Interests: Declaration of Competing Interest Not applicable., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: While blunt cerebrovascular injury (BCVI) is a rare complication of blunt trauma, it is associated with significant morbidity and mortality. In the pediatric population, unique anatomy and development require screening criteria that accurately diagnose these injuries while limiting unwarranted radiation., Methods: We searched Medline OVID, EMBASE, and Cochrane Library databases for studies that investigated the risk factors of BCVI in individuals younger than 18 years of age. We adhered to the Preferred Reporting Items in Systematic Reviews and Meta-Analyses (PRISMA) guidelines and assessed the quality of each study using the Newcastle-Ottawa Scale. We compared key characteristics of the papers, including incidence of BCVI, incidence of risk factors, and statistical significance of risk factors., Results: Of 1304 studies, 16 met the inclusion criteria. Of these, 15 were retrospective cohort studies and one was a retrospective case control study. Most of the studies included all pediatric blunt trauma admissions, but four only included those which underwent imaging, one only included those with cervical seatbelt sign, and one excluded those who did not survive 24-h post-admission. The ages included as pediatric varied between papers. Papers examined different risk factors and reported differing statistical significances. Though no single risk factor was found to be statistically significant in every study, cervical spine and skull fractures were found to be significant by most. Maxillofacial fractures, depressed GCS score, and stroke were found to be statistically significant by multiple studies. Twelve studies examined cervical soft tissue injury, and none found it to be statistically significant., Conclusions: The risk factors most found to be statistically significant for BCVI were cervical spine fracture (10/16 studies), skull fracture (9/16), maxillofacial fractures (7/16), depressed GCS score (5/16), and stroke (5/16). There is a need for prospective studies on this topic., Level of Evidence: Level III, Systematic Review., Competing Interests: Declaration of Competing Interest The authors report no conflicts of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Blunt cerebrovascular injury (BCVI) is defined as blunt trauma to the head and neck leading to damage to the vertebral and/or carotid arteries; debate exists regarding which children are considered at high risk for BCVI and in need of angiographic/vessel imaging. We previously proposed a screening tool, the McGovern score, to identify pediatric trauma patients at high risk for BCVI, and we aim to validate the McGovern score by pooling data from multiple pediatric trauma centers. This is a multi-center, hospital-based, cohort study from all prospectively registered pediatric (<16 years of age) trauma patients who presented to the emergency department (ED) between 2003 and 2017 at six Level 1 pediatric trauma centers. The registry was retrospectively queried for patients who received a computed tomography angiogram (CTA) as a screening method for BCVI. Age, length of follow-up, mechanism of injury (MOI), arrival Glasgow Coma Scale (GCS) score, and focal neurological deficit were recorded. Radiological variables queried were the presence of a carotid canal fracture, petrous temporal bone fracture, and CT presence of infarction. Patients with BCVI were queried for mode of treatment, type of intracranial injury, artery damaged, and BCVI injury grade. The McGovern score was calculated for all patients who underwent CTA across all data groups. A total of 1012 patients underwent CTA; 72 of these patients were found to have BCVI, 51 of which were in the validation cohort. Across all data groups, the McGovern score has a >80% sensitivity (SN) and >98% negative predictive value (NPV). The McGovern score for pediatric BCVI is an effective, generalizable screening tool.

Traumatic injury is linked increasingly to alterations in both stress response systems and psychological health. We investigated reactivity of salivary analytes of the hypothalamic-pituitary-adrenal axis (cortisol) and autonomic nervous system (salivary alpha amylase, sAA) during a psychosocial stress procedure in relation to psychological health outcomes. In a prospective cohort design, stress reactivity of children ages 8 to 15 years hospitalized for traumatic brain injury (TBI; n  = 74) or extracranial injury (EI; n  = 35) was compared with healthy controls ( n  = 51) 7 months after injury. Area under the curve increase (AUCinc) assessed pre-stressor to post-stressor cortisol and sAA values. Multi-variable general linear models evaluated demographic, family functioning, group, cortisol, and sAA AUCinc, and their interactions in relation to concurrent child and parent ratings of emotion regulation and internalizing and externalizing problems. Although AUCinc values were similar across groups, their relations with outcomes varied by group. Higher stress reactivity is typically associated with fewer adjustment problems. Relative to controls, greater sAA reactivity was associated with greater emotion dysregulation after TBI. In contrast, the relation of sAA reactivity with internalizing and generalized anxiety scores was flatter for both TBI and EI groups. The flattened and/or reversed direction of sAA reactivity with psychological health outcomes after TBI, and to a lesser degree EI, suggests autonomic nervous system dysregulation. Across groups, sAA reactivity interacted with sex on several psychological health outcomes with greater dysregulation in girls than in boys. Our findings highlight altered sAA, but not cortisol reactivity, as a potential mechanism of biological vulnerability associated with poorer adjustment after TBI.

Background and Objective: Stem cell therapy is a regenerative medicine modality that has the potential to decrease morbidity and mortality by promoting tissue regeneration or modulating the inflammatory response. An increase in the number of clinical trials investigating the efficacy and safety of stem cell therapy in pediatric diseases has led to advancements in this field. Currently, multiple sources and types of stem cells have been utilized in the treatment of pediatric diseases. This review aims to inform researchers and clinicians about preclinical and clinical stem cell therapy trials in pediatric patients. We discuss the different types of stem cells and the wide spectrum of stem cell therapy trials for pediatric diseases, with an emphasis on the outcomes and advancements in the field., Methods: PubMed and clinicaltrials.gov databases were searched on October 28, 2022 using the following Medical Subject Headings (MeSH) terms "stem cell" or "stem cell therapy" with an age filter <18 years. Our search was limited to publications published between 2000 and 2022., Key Content and Findings: Diverse sources of stem cells have different properties and mechanisms of action, which allow tailored application of stem cells according to the pathophysiology of the disease. Advancements in stem cell therapies for pediatric diseases have led to improvements in clinical outcomes in some pediatric diseases or in quality of life, such therapies represent a potential alternative to the current treatment modalities., Conclusions: Stem cell therapy in pediatric diseases has shown promising results and outcomes. However, further studies focusing on the implementation and optimal treatment timeframe are needed. An increase in preclinical and clinical trials of stem cell therapy targeting pediatric patients is required to advance our therapeutic applications., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tp.amegroups.com/article/view/10.21037/tp-23-92/coif). The series “The Impact of the Progresses of Knowledge and Technologies in Pediatrics” was commissioned by the editorial office without any funding or sponsorship. RES received support for attending meetings and/or travel from University of Texas. CSC reports grants/contracts received from NIH, DOD/MTEC/CDMRP, HopeBio, and Athersys, royalties or licenses from EMIT, Coagulex, and Cellvation, consulting fees from Stream Biomedical, payments or honoraria from CellCare Australia, and Generate Life Sciences, and support for attending meetings and/or travel from CTTACC. CSC has patents planned, issued or pending by University of Texas, participates on advisory board for Duke University, and holds stock or stock options from Cellvation, Inc. The authors have no other conflicts of interests to declare., (2023 Translational Pediatrics. All rights reserved.)

Background: Microglia are a primary mediator of the neuroinflammatory response to neurologic injury, such as that in traumatic brain injury. Their response includes changes to their cytokine expression, metabolic profile, and immunophenotype. Dexmedetomidine (DEX) is an α 2 adrenergic agonist used as a sedative in critically ill patients, such as those with traumatic brain injury. Given its pharmacologic properties, DEX may alter the phenotype of inflammatory microglia., Methods: Primary microglia were isolated from Sprague-Dawley rats and cultured. Microglia were activated using multiple mediators: lipopolysaccharide (LPS), polyinosinic-polycytidylic acid (Poly I:C), and traumatic brain injury damage-associated molecular patterns (DAMP) from a rat that sustained a prior controlled cortical impact injury. After activation, cultures were treated with DEX. At the 24-h interval, the cell supernatant and cells were collected for the following studies: cytokine expression (tumor necrosis factor-α [TNFα], interleukin-10 [IL-10]) via enzyme-linked immunosorbent assay, 6-phosphofructokinase enzyme activity assay, and immunophenotype profiling with flow cytometry. Cytokine expression and metabolic enzyme activity data were analyzed using two-way analysis of variance. Cell surface marker expression was analyzed using FlowJo software., Results: In LPS-treated cultures, DEX treatment decreased the expression of TNFα from microglia (mean difference = 121.5 ± 15.96 pg/mL; p < 0.0001). Overall, DEX-treated cultures had a lower expression of IL-10 than nontreated cultures (mean difference = 39.33 ± 14.50 pg/mL, p < 0.0001). DEX decreased IL-10 expression in LPS-stimulated microglia (mean difference = 74.93 ± 12.50 pg/mL, p = 0.0039) and Poly I:C-stimulated microglia (mean difference = 23.27 ± 6.405 pg/mL, p = 0.0221). In DAMP-stimulated microglia, DEX decreased the activity of 6-phosphofructokinase (mean difference = 18.79 ± 6.508 units/mL; p = 0.0421). The microglial immunophenotype was altered to varying degrees with different inflammatory stimuli and DEX treatment., Conclusions: DEX may alter the neuroinflammatory response of microglia. By altering the microglial profile, DEX may affect the progression of neurologic injury., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and Neurocritical Care Society.)

This narrative review article seeks to highlight the effects of citrate on physiology during massive transfusion of the bleeding patient., Data Sources: A limited library of curated articles was created using search terms including "citrate intoxication," "citrate massive transfusion," "citrate pharmacokinetics," "hypocalcemia of trauma," "citrate phosphate dextrose," and "hypocalcemia in massive transfusion." Review articles, as well as prospective and retrospective studies were selected based on their relevance for inclusion in this review., Study Selection: Given the limited number of relevant studies, studies were reviewed and included if they were written in English. This is not a systematic review nor a meta-analysis., Data Extraction and Synthesis: As this is not a meta-analysis, new statistical analyses were not performed. Relevant data were summarized in the body of the text., Conclusions: The physiologic effects of citrate independent of hypocalcemia are poorly understood. While a healthy individual can rapidly clear the citrate in a unit of blood (either through the citric acid cycle or direct excretion in urine), the physiology of hemorrhagic shock can lead to decreased clearance and prolonged circulation of citrate. The so-called "Diamond of Death" of bleeding-coagulopathy, acidemia, hypothermia, and hypocalcemia-has a dynamic interaction with citrate that can lead to a death spiral. Hypothermia and acidemia both decrease citrate clearance while circulating citrate decreases thrombin generation and platelet function, leading to ionized hypocalcemia, coagulopathy, and need for further transfusion resulting in a new citrate load. Whole blood transfusion typically requires lower volumes of transfused product than component therapy alone, resulting in a lower citrate burden. Efforts should be made to limit the amount of citrate infused into a patient in hemorrhagic shock while simultaneously addressing the induced hypocalcemia., Competing Interests: Drs. Cox and Gill received sponsored research funding from Coagulex and Equity/Royalty (interest via UTHealth). UTHealth has an institutional conflicts of interest for holding equity in Coagulex (to Dr. Gill). Dr. Olson is supported by National Institute of Neurological Disorders and Stroke R21NS116302. Dr. Schriner was supported by a T32 fellowship from the National Institute of General Medical Sciences of the National Institutes of Health under award number 2T32GM008792. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.)

The TRPM4 gene codes for a membrane ion channel subunit related to inflammation in the central nervous system. Recent investigation has identified an association between TRPM4 single nucleotide polymorphisms (SNPs) rs8104571 and rs150391806 and increased intracranial (ICP) pressure following traumatic brain injury (TBI). We assessed the influence of these genotypes on clinical outcomes and ICP in TBI patients. We included 292 trauma patients with TBI. DNA extraction and real-time PCR were used for TRPM4 rs8104571 and rs150391806 allele discrimination. Five participants were determined to have the rs8104571 homozygous variant genotype, and 20 participants were identified as heterozygotes; 24 of these 25 participants were African American. No participants had rs150391806 variant alleles, preventing further analysis of this SNP. Genotypes containing the rs8104571 variant allele were associated with decreased Glasgow outcome scale-extended (GOSE) score (P = 0.0231), which was also consistent within our African-American subpopulation (P = 0.0324). Regression analysis identified an association between rs8104571 variant homozygotes and mortality within our overall population (P = 0.0230) and among African Americans (P = 0.0244). Participants with rs8104571 variant genotypes exhibited an overall increase in ICP (P = 0.0077), although a greater frequency of ICP measurements > 25 mmHg was observed in wild-type participants (P =  < 0.0001). We report an association between the TRPM4 rs8104571 variant allele and poor outcomes following TBI. These findings can potentially be translated into a precision medicine approach for African Americans following TBI utilizing TRPM4-specific pharmaceutical interventions. Validation through larger cohorts is warranted., (© 2023. The Author(s).)

Cell-based therapies are an emerging biopharmaceutical paradigm under investigation for the treatment of a range of neurological disorders. Accumulating evidence is demonstrating that cell-based therapies might be effective, but the mechanism of action remains unclear. In this Review, we synthesize results from over 20 years of animal studies that illustrate how transdifferentiation, cell replacement and restoration of damaged tissues in the CNS are highly unlikely mechanisms. We consider the evidence for an alternative model that we refer to as the bioreactor hypothesis, in which exogenous cells migrate to peripheral organs and modulate and reprogramme host immune cells to generate an anti-inflammatory, regenerative environment. The results of clinical trials clearly demonstrate a role for immunomodulation in the effects of cell-based therapies. Greater understanding of these mechanisms could facilitate the optimization of cell-based therapies for a variety of neurological disorders., (© 2022. Springer Nature Limited.)

Increased microvascular permeability at the level of the blood-brain barrier (BBB) often leads to vasogenic brain edema following traumatic brain injury (TBI). These pathologic conditions compromise the integrity of the neurovascular unit resulting in severe brain dysfunction. To quantify this permeability and assess ionic equillibrium, preclinical researchers have relied on the use of various molecular weight permeable dyes such as Evans Blue that normally cannot enter the brain parenchyma under homeostatic conditions. Evans Blue, the most cited of the molecular weight dyes, has reported reproducibility issues because of harsh extraction processes, suboptimal detection via absorbance, and wide excitation fluorescence spectra associated with the dye. Our laboratory group transitioned to Alexa Fluor 680, a far-red dye with improved sensitivity compared to Evans Blue and thus improved reproducibility to alleviate this issue. To evaluate our reproducibility and increase the rigor of our experimental design, we retrospectively analyzed our controlled cortical impact (CCI) experiments over the past 10 years to evaluate effect size with larger samples and potential sources of variability. All of our BBB permeability experiments were performed with Male, Sprague Dawley rats weighing between 225 and 300 g. Historically, Sprague Dawleys were randomly divided into treatment groups: SHAM, CCI, and a stem cell-based treatment from years 2007-2020. The assessment of microvascular hyperpermeability were evaluated by comparing the mean at minimum threshold, area at 1 k-2 k, and intensity density obtained from Alexa Fluor 680 permeability data. Studies utilizing Evans Blue were further compared by tip depth, diameter size, and the hemisphere of injury. Statistical evaluation utilizing the G Power software analysis did not yield a significant difference in sample size comparing experimental groups for Evans Blue and Alexa Fluor 680 analyzed brain tissue. Our analysis also demonstrated a trend in that recent studies (years 2018-2020) have yielded more compact sample sizes between experimental groups in Alexa Fluor 680 analyzed rats. This retrospective study further revealed that Alexa Fluor 680 image analysis provides greater sensitivity to BBB permeability following TBI in comparison to Evans Blue. Significant differences in sample size were not detected between Evans Blue and Alexa Fluor 680; there were significant differences found throughout year to year analysis at the lower range of thresholds. SUMMARY STATEMENT: This work provides a comparative analysis of BBB permeability assay techniques after CCI model of injury in rats., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Mesenchymal stromal cells (MSC) undergo functional maturation upon their migration from bone marrow and introduction to a site of injury. This inflammatory licensing leads to heightened immune regulation via cell-to-cell interaction and the secretion of immunomodulatory molecules, such as anti-inflammatory mediators and antioxidants. Pro-inflammatory cytokines are a recognized catalyst of inflammatory licensing; however, biomechanical forces, such as fluid shear stress, are a second, distinct class of stimuli that incite functional maturation. Here we show mechanotransduction, achieved by exposing MSC to various grades of wall shear stress (WSS) within a scalable conditioning platform, enhances the immunomodulatory potential of MSC independent of classical pro-inflammatory cytokines. A dose-dependent effect of WSS on potency is evidenced by production of prostaglandin E2 (PGE 2 ) and indoleamine 2,3 dioxygenase 1 (IDO1), as well as suppression of tumor necrosis factor-α (TNF- α) and interferon-γ (IFN-γ) production by activated immune cells. Consistent, reproducible licensing is demonstrated in adipose tissue and bone marrow human derived MSC without significant impact on cell viability, cellular yield, or identity. Transcriptome analysis of WSS-conditioned BM-MSC elucidates the broader phenotypic implications on the differential expression of immunomodulatory factors. These results suggest mechanotransduction as a viable, scalable pre-conditioning alternative to pro-inflammatory cytokines. Enhancing the immunomodulatory capacity of MSC via biomechanical conditioning represents a novel cell therapy manufacturing approach., Competing Interests: SO has received research support from Athersys, CBR Systems, Hope Bio, Generate Life Sciences, Cellvation, and Biostage. CC has received research support from Athersys, CBR Systems, Hope Bio, Biostage, Generate Life Sciences, and Cellvation, and is on the Scientific Advisory Board of Cellvation and Generate Life Sciences. BG is on the Scientific Advisory Board of Cellvation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Skibber, Olson, Prabhakara, Gill and Cox.)

Abstract: Platelets are subcellular anucleate components of blood primarily responsible for initiating and maintaining hemostasis. After injury to a blood vessel, platelets can be activated via several pathways, resulting in changed shape, adherence to the injury site, aggregation to form a plug, degranulation to initiate activation in other nearby platelets, and acceleration of thrombin formation to convert fibrinogen to fibrin before contracting to strengthen the clot. Platelet function assays use agonists to induce and measure one or more of these processes to identify alterations in platelet function that increase the likelihood of bleeding or thrombotic events. In severe trauma, these assays have revealed that platelet dysfunction is strongly associated with poor clinical outcomes. However, to date, the mechanism(s) causing clinically significant platelet dysfunction remain poorly understood. We review the pros, cons, and evidence for use of many of the popular assays in trauma, discuss limitations of their use in this patient population, and present approaches that can be taken to develop improved functional assays capable of elucidating mechanisms of trauma-induced platelet dysfunction. Platelet dysfunction in trauma has been associated with need for transfusions and mortality; however, most of the current platelet function assays were not designed for evaluating trauma patients, and there are limited data regarding their use in this population. New or improved functional assays will help define the mechanisms by which platelet dysfunction occurs, as well as help optimize future treatment., Competing Interests: C.S.C. has the following relationships to disclose: Coagulex, Inc. sponsored research funding and equity/royalty (interest via The University of Texas Health Science Center at Houston [UTHealth]). B.S.G. has the following relationships to disclose: Coagulex, Inc. sponsored research funding and equity/royalty (interest via UTHealth). UTHealth has an institutional conflict of interest for holding equity in Coagulex. C.E.W. receives funding from the William Stamps Farish Fund, the Howell Family Foundation, and the James H. “Red” Duke Professorship. Unrelated to the present effort, C.E.W. holds a financial interest in Dicisio Health LLC and receives grants from Grifols and Athersys. J.C.C. has funding from the Department of Defense, Aniara, and has received speaker honoraria and research funding from Grifols. S.D.O. is supported by National Institute of Neurological Diseases and Stroke of the National Institutes of Health award number R21NS116302. J.B.S. is supported by a T32 fellowship from the National Institute of General Medical Sciences of the National Institutes of Health under award number T32GM008792., (Copyright © 2022 by the Shock Society.)

We examined an autologous mononuclear-cell-therapy-based approach to treat cerebral palsy using autologous umbilical cord blood or bone-marrow-derived mononuclear cells. The primary objective was to determine if autologous cells are safe to administer in children with cerebral palsy. The secondary objectives were to determine if there was improvement in motor function of patients 12 months after infusion using the Gross Motor Function Measure and to evaluate impact of treatment on corticospinal tract microstructure as determined by radial diffusivity measurement. This Phase 1/2a trial was a randomized, blinded, placebo-controlled, crossover study in children aged 2-10 years of age with cerebral palsy enrolled between November 2013 and November 2016. Participants were randomized to 2:1 treatment:placebo. Treatment was either autologous bone-marrow-derived mononuclear cells or autologous umbilical cord blood. All participants who enrolled and completed their baseline visit planned to return for follow-up visits at 6 months, 12 months and 24 months after the baseline visit. At the 12-month post-treatment visit, participants who originally received the placebo received either bone-marrow-derived mononuclear cell or umbilical cord blood treatment. Twenty participants were included; 7 initially randomized to placebo, and 13 randomized to treatment. Five participants randomized to placebo received bone-marrow-derived mononuclear cells, and 2 received umbilical cord blood at the 12-month visit. None of the participants experienced adverse events related to the stem cell infusion. Cell infusion at the doses used in our study did not dramatically alter motor function. We observed concordant bilateral changes in radial diffusivity in 10 of 15 cases where each corticospinal tract could be reconstructed in each hemisphere. In 60% of these cases (6/10), concordant decreases in bilateral corticospinal tract radial diffusivity occurred post-treatment. In addition, 100% of unilateral corticospinal tract cases (3/3) exhibited decreased corticospinal tract radial diffusivity post-treatment. In our discordant cases ( n  = 5), directionality of changes in corticospinal tract radial diffusivity appeared to coincide with handedness. There was a significant improvement in corticospinal tract radial diffusivity that appears related to handedness. Connectivity strength increased in either or both pathways (corticio-striatal and thalamo-cortical) in each participant at 12 months post-treatment. These data suggest that both stem cell infusions are safe. There may be an improvement in myelination in some groups of patients that correlate with small improvements in the Gross Motor Function Measure scales. A larger autologous cord blood trial is impractical at current rates of blood banking. Either increased private banking or matched units would be required to perform a larger-scale trial., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Traumatic brain injury (TBI) results in a cascade of cellular responses, which produce neuroinflammation, partly due to the activation of microglia. Accurate identification of microglial populations is key to understanding therapeutic approaches that modify microglial responses to TBI and improve long-term outcome measures. Notably, previous studies often utilized an outdated convention to describe microglial phenotypes. We conducted a temporal analysis of the response to controlled cortical impact (CCI) in rat microglia between ipsilateral and contralateral hemispheres across seven time points, identified microglia through expression of activation markers including CD45, CD11b/c, and p2y12 receptor and evaluated their activation state using additional markers of CD32, CD86, RT1B, CD200R, and CD163. We identified unique sub-populations of microglial cells that express individual or combination of activation markers across time points. We further portrayed how the size of these sub-populations changes through time, corresponding to stages in TBI response. We described longitudinal changes in microglial population after CCI in two different locations using activation markers, showing clear separation into cellular sub-populations that feature different temporal patterns of markers after injury. These changes may aid in understanding the symptomatic progression following TBI and help define microglial subpopulations beyond the outdated M1/M2 paradigm., (© 2022. The Author(s).)

In children, diarrhea has a global incidence of 2.7 episodes per child-year and contributes to significant disease burden and mortality in children under 5 years of age. Chronic diarrhea, defined as diarrhea lasting for more than 2 weeks, may be particularly challenging to evaluate and manage in children under 2 years of age. While most have infectious enteritis or cow milk protein intolerance, others have conditions such as malnutrition, anatomic abnormalities, or congenital enteropathies that can be challenging to diagnose and treat. We present here a complex case of chronic diarrhea in an infant and highlight such diagnostic and therapeutic challenges., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Introduction: Traumatic brain injury is a leading cause of injury-related death and morbidity. Multiple clinical and pre-clinical studies have reported various results regarding sex-based differences in TBI. Our accepted rodent model of traumatic brain injury was used to identify sex-based differences in the pathological features of TBI., Methods: Male and female Sprague-Dawley rats were subjected to either controlled-cortical impact (CCI) or sham injury; brain tissue was harvested at different time intervals depending on the specific study. Blood-brain barrier (BBB) analysis was performed using infrared imaging to measure fluorescence dye extravasation. Microglia and splenocytes were characterized with traditional flow cytometry; microglia markers such as CD45, P2Y12, CD32, and CD163 were analyzed with t-distributed stochastic neighbor embedding (t-SNE). Flow cytometry was used to study tissue cytokine levels, and supplemented with ELISAs of TNF-⍺, IL-17, and IL-1β of the ipsilateral hemisphere tissue., Results: CCI groups of both sexes recorded a higher BBB permeability at 72 hours post-injury than their respective sham groups. There was significant difference in the integrated density value of BBB permeability between the male CCI group and the female CCI group (female CCI mean = 3.08 x 108 ± 2.83 x 107, male CCI mean = 2.20 x 108 ± 4.05 x 106, p = 0.0210), but otherwise no differences were observed. Traditional flow cytometry did not distinguish any sex-based difference in regards to splenocyte cell population after CCI. t-SNE did not reveal any significant difference between the male and female injury groups in the activation of microglia. Cytokine analysis after injury by flow cytometry and ELISA was limited in differences at the time point of 6 hours post-injury., Conclusion: In our rodent model of traumatic brain injury, sex-based differences in pathology and neuroinflammation at specified time points are limited, and only noted in one specific analysis of BBB permeability., Competing Interests: CC is on the Scientific Advisory Board of Cellvation and CBR. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Scott, Prabhakara, Walters, Olson and Cox.)

Introduction: Resection and reconstruction of the esophagus remains fraught with morbidity and mortality. Recently, data from a porcine reconstruction model revealed that segmental esophageal reconstruction using an autologous mesenchymal stromal cell-seeded polyurethane graft (Cellspan esophageal implant [CEI]) can facilitate esophageal regrowth and regeneration. To this end, a patient requiring a full circumferential esophageal segmental reconstruction after a complex multiorgan tumor resection was approved for an investigational treatment under the Food and Drug Administration Expanded Access Use (Investigational New Drug 17402)., Methods: Autologous adipose-derived mesenchymal stromal cells (Ad-MSCs) were isolated from the Emergency Investigational New Drug patient approximately 4 weeks before surgery from an adipose tissue biopsy specimen. The Ad-MSCs were grown and expanded under current Good Manufacturing Practice manufacturing conditions. The cells were then seeded onto a polyurethane fiber mesh scaffold (Cellspan scaffold) and cultured in a custom bioreactor to manufacture the final CEI graft. The cell-seeded scaffold was then shipped to the surgical site for surgical implantation. After removal of a tumor mass and a full circumferential 4 cm segment of the esophagus that was invaded by the tumor, the CEI was implanted by suturing the tubular CEI graft to both ends of the remaining native esophagus using end-to-end anastomosis., Results: In this case report, we found that a clinical-grade, tissue-engineered esophageal graft can be used for segmental esophageal reconstruction in a human patient. This report reveals that the graft supports regeneration of the esophageal conduit. Histologic analysis of the tissue postmortem, 7.5 months after the implantation procedure, revealed complete luminal epithelialization and partial esophageal tissue regeneration., Conclusions: Autologous Ad-MSC seeded onto a tubular CEI tissue-engineered graft stimulates tissue regeneration following implantation after a full circumferential esophageal resection., (© 2021 THE AUTHORS.)

Background: Although physiologic differences exist between younger and older children, pediatric trauma analyses are weighted toward older patients. Trauma-induced coagulopathy, determined by rapid thrombelastography (rTEG), is a predictor of outcome in trauma patients, but the significance of rTEG values among very young trauma patients remains unknown. Our objective was to identify the prehospital or physiologic factors, including rTEG values, that were associated with mortality in trauma patients younger than 5 y old., Materials and Methods: Patients younger than 5 y old that met the highest-level trauma activation criteria at an academic children's hospital from 2010-2016 were included. Data regarding demographics, pre-hospital management, laboratory values, injury severity, and outcome were queried. Univariate and multivariate analyses were performed comparing survivors and non-survivors., Results: A total of 356 patients were included. 60% were male, and the median age was 3 y (IQR 1-4). Overall mortality was 13% (n = 45); brain injury (91%) and hemorrhage (9%) were the causes of death. Compared to survivors, rTEG values in nonsurvivors showed longer activated clotting time and slower speed of clot formation. Clot strength was also decreased in nonsurvivors. On stepwise regression modeling, rTEG values were not significant predictors of mortality. Admission base deficit, arrival temperature, and head injury severity were identified as independent predictors of mortality., Conclusions: While rTEG identified coagulopathy in trauma patients < 5 y old, it was not an independent predictor of mortality. Our findings suggest that trauma providers should pay close attention to admission base deficit, arrival temperature, and head injury severity when managing the youngest trauma patients., Competing Interests: Disclosures Dr. Cotton has served on the Scientific Advisory Council for Haemonetics Corp (Braintree, MA). The remaining authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article., (Copyright © 2021. Published by Elsevier Inc.)

Objective: To model pre-injury child and family factors associated with the trajectory of internalizing and externalizing behavior problems across the first 3 years in children with pediatric traumatic brain injury (TBI) relative to children with orthopedic injuries (OI). Parent-reported emotional symptoms and conduct problems were expected to have unique and shared predictors. We hypothesized that TBI, female sex, greater pre-injury executive dysfunction, adjustment problems, lower income, and family dysfunction would be associated with less favorable outcomes. Methods: In a prospective longitudinal cohort study, we examined the level of behavior problems at 12 months after injury and rate of change from pre-injury to 12 months and from 12 to 36 months in children ages 4-15 years with mild to severe TBI relative to children with OI. A structural equation model framework incorporated injury characteristics, child demographic variables, as well as pre-injury child reserve and family attributes. Internalizing and externalizing behavior problems were indexed using the parent-rated Emotional Symptoms and Conduct Problems scales from the Strengths and Difficulties questionnaire. Results: The analysis cohort of 534 children [64% boys, M (SD) 8.8 (4.3) years of age] included 395 with mild to severe TBI and 139 with OI. Behavior ratings were higher after TBI than OI but did not differ by TBI severity. TBI, higher pre-injury executive dysfunction, and lower income predicted the level and trajectory of both Emotional Symptoms and Conduct Problems at 12 months. Female sex and poorer family functioning were vulnerability factors associated with greater increase and change in Emotional Symptoms by 12 months after injury; unique predictors of Conduct Problems included younger age and prior emotional/behavioral problems. Across the long-term follow-up from 12 to 36 months, Emotional Symptoms increased significantly and Conduct Problems stabilized. TBI was not a significant predictor of change during the chronic stage of recovery. Conclusions: After TBI, Emotional Symptoms and Conduct Problem scores were elevated, had different trajectories of change, increased or stayed elevated from 12 to 36 months after TBI, and did not return to pre-injury levels across the 3 year follow-up. These findings highlight the importance of addressing behavioral problems after TBI across an extended time frame., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Ewing-Cobbs, Montroy, Clark, Holubkov, Cox and Keenan.)

Bone marrow mononuclear cells (MNCs) attenuate secondary degeneration and enhance recovery in stroke animal models. In a nonrandomized clinical trial, we imaged 37 patients with stroke: 17 patients treated with MNCs (treated) and 20 patients who received standard of care (nontreated) at 1, 3, and 12 months onset of stroke on 3.0T MRI system. Three-dimensional anatomical and diffusion tensor images were obtained. The integrity of the corticospinal tract was assessed by measuring absolute and relative fractional anisotropy (FA) and mean diffusivity (MD) in the rostral pons (RP), posterior limb of the internal capsule, and corona radiata by drawing regions of interest. Infarct volume and stroke severity, which was assessed via the NIH Stroke Scale (NIHSS), were higher in the MNC group compared with the nontreated patients, which is a major limitation. Overall, the relative FA (rFA) of the nontreated patients exhibited continued reduction and an increase in relative MD (rMD) from 1 to 12 months, whereas despite larger infarcts and higher severity, treated patients displayed an increase in rFA from 3 to 12 months and no change in rMD. Contrary to the nontreated group, the treated patients' rFA was also significantly correlated (P < .05) with NIHSS score in the RP at all time points, whereas rMD at the last two., (© 2021 The Authors. STEM CELLS TRANSLATIONAL MEDICINE published by Wiley Periodicals LLC on behalf of AlphaMed Press.)

Myosin Light Chain (MLC) regulates platelet contraction through its phosphorylation by Myosin Light Chain Kinase (MLCK) or dephosphorylation by Myosin Light Chain Phosphatase (MLCP). The correlation between platelet contraction force and levels of MLC phosphorylation is unknown. We investigate the relationship between platelet contraction force and MLC phosphorylation using a novel microelectromechanical (MEMS) based clot contraction sensor (CCS). The MLCK and MLCP pair were interrogated by inhibitors and activators of platelet function. The CCS was fabricated from silicon using photolithography techniques and force was validated over a range of deflection for different chip spring constants. The force of platelet contraction measured by the clot contraction sensor (CCS) was compared to the degree of MLC phosphorylation by Western Blotting (WB) and ELISA. Stimulators of MLC phosphorylation produced higher contraction force, higher phosphorylated MLC signal in ELISA and higher intensity bands in WB. Inhibitors of MLC phosphorylation produced the opposite. Contraction force is linearly related to levels of phosphorylated MLC. Direct measurements of clot contractile force are possible using a MEMS sensor platform and correlate linearly with the degree of MLC phosphorylation during coagulation. Measured force represents the mechanical output of the actin/myosin motor in platelets regulated by myosin light chain phosphorylation.

Traumatic brain injury (TBI) causes both physical disruption of the blood brain barrier (BBB) and altered immune responses that can lead to significant secondary brain injury and chronic inflammation within the central nervous system (CNS). Cell therapies, including mesenchymal stromal cells (MSC), have been shown to restore BBB integrity and augment endogenous splenic regulatory T cells (Treg), a subset of CD4+ T cells that function to regulate immune responses and prevent autoimmunity. We have recently shown that infusion of human cord blood-derived Treg decreased neuroinflammation after TBI in vivo and in vitro. However, while both cells have demonstrated anti-inflammatory and regenerative potential, they likely utilize differing, although potentially overlapping, mechanisms. Furthermore, studies investigating these two cell types together, as a combination therapy, are lacking. In this study, we compared the ability of Treg+MSC combination therapy, as well as MSC and Treg monotherapies, to improve BBB permeability in vivo and suppress inflammation in vitro. While Treg+MSC combination did not significantly augment potency in vivo, our in vitro data demonstrates that combination therapy may augment therapeutic potency and immunosuppressive potential compared to Treg or MSC monotherapy., Competing Interests: The authors have read the journal’s policy and have the following competing interests: SDO was a Guest Editor on the “Stem Cell Plasticity in Tissue Repair and Regeneration” Call for Papers for PLOS ONE. CSC has received research support from Athersys, CBR Systems, Hope Bio, Biostage, and is on the Scientific Advisory Board of Cellvation, Biostage, and CBR. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Importance: Executive functions are critical for school and social success. Although these functions are adversely affected by pediatric traumatic brain injury (TBI), recovery patterns are not well established., Objective: To examine 3-year trajectories of selected children's executive functions after TBI., Design, Setting, and Participants: This prospective cohort study was conducted from January 22, 2013, to September 30, 2015, with 3-year follow-up at the level I pediatric trauma centers Primary Children's Hospital in Salt Lake City, Utah and Children's Memorial Hermann Hospital in Houston, Texas. Study participants included children aged 2 to 15 years with TBI or orthopedic injury (OI) who were treated at the participating hospitals. Children were consecutively recruited and stratified by injury severity and age group. A total of 625 children consented and completed a baseline survey; 559 (89%) children completed at least 1 follow-up and composed the analysis cohort. It was hypothesized that recovery would differ by injury severity, age at injury, and sex. Data analyses were performed from June to October 2019., Main Outcomes and Measures: Growth curve models examined the pattern of change in the Emotional Control, Inhibit, Working Memory, and Plan-Organize subscales of the Behavior Rating Inventory of Executive Function (BRIEF) or BRIEF-Preschool. For all BRIEF subscales, higher scores indicate worse symptoms, and a score of 65 or greater represents clinical impairment., Results: A total of 559 children (mean [SD] age, 8.6 [4.4] years; 356 boys [64%], 328 non-Hispanic White children [59%]) were included in the study: 155 (28%) children had mild TBI, 162 (29%) had complicated mild or moderate TBI, 90 (16%) had severe TBI, and 152 (27%) had OI. Growth curve trajectories varied by BRIEF subscale and injury severity. Overall, children with TBI did not return to their preinjury baseline, with a stepwise worsening of each outcome at 36 months by TBI severity compared with OI. Among children with severe TBI, trajectories accelerated fastest, indicating increased problems, from injury to 12 months for the Emotional Control (9.0 points; 95% CI, 6.0-11.9 points), Inhibit (3.6 points; 95% CI, 1.6-5.6 points), and Working Memory (7.0 points; 95% CI, 4.1-9.9 points) subscales. Their trajectories plateaued, with a secondary acceleration before 36 months for the Emotional Control and Working Memory subscales. Children with mild TBI had worse 36-month scores on all subscales except Inhibit compared with OI. Recovery patterns were similar for boys and girls., Conclusions and Relevance: In this longitudinal cohort study of children with TBI, trajectory analysis revealed that some children worsen after a recovery plateau, suggesting a need for longitudinal reassessment beyond 1 year postinjury.

The inflammatory response after traumatic brain injury (TBI) can lead to significant secondary brain injury and chronic inflammation within the central nervous system. Cell therapies, including mesenchymal stromal cells (MSC), have led to improvements in animal models of TBI and are under investigation in human trials. One potential mechanism for the therapeutic potential of MSC is their ability to augment the endogenous response of immune suppressive regulatory T cells (Treg). We have recently shown that infusion of human cord blood Treg decreased chronic microgliosis after TBI and altered the systemic immune response in a rodent model. These cells likely use both overlapping and distinct mechanisms to modulate the immune system; therefore, combining Treg and MSC as a combination therapy may confer therapeutic benefit over either monotherapy. However, investigation of Treg + MSC combination therapy in TBI is lacking. In this study, we compared the ability MSC + Treg combination therapy, as well as MSC and Treg monotherapies, to inhibit the neuroinflammatory response to TBI in vivo and in vitro. Treg + MSC combination therapy demonstrated increased potency to reduce the neuro- and peripheral inflammatory response compared to monotherapy; furthermore, the timing of infusion proved to be a significant variable in the efficacy of both MSC monotherapy and Treg + MSC combination therapy in vivo and in vitro., (©AlphaMed Press 2020.)

Traumatic brain injury (TBI) is a chronic, life threatening injury for which few effective interventions are available. Evidence in animal models suggests un-checked immune activation may contribute to the pathophysiology. Changes in regional density of active brain microglia can be quantified in vivo with positron emission topography (PET) with the relatively selective radiotracer, peripheral benzodiazepine receptor 28 (11 C-PBR28). Phenotypic assessment (activated vs resting) can subsequently be assessed (ex vivo) using morphological techniques. To elucidate the mechanistic contribution of immune cells in due to TBI, we employed a hybrid approach involving both in vivo (11 C-PBR28 PET) and ex vivo (morphology) to elucidate the role of immune cells in a controlled cortical impact (CCI), a rodent model for TBI. Density of activated brain microglia/macrophages was quantified 120 hours after injury using the standardized uptake value (SUV) approach. Ex vivo morphological analysis from specific brain regions using IBA-1 antibodies differentiated ramified (resting) from amoeboid (activated) immune cells. Additional immunostaining of PBRs facilitated co-localization of PBRs with IBA-1 staining to further validate PET data. Injured animals displayed greater PBR28suv when compared to sham animals. Immunohistochemistry demonstrated elevated density of amoeboid microglia/macrophages in the ipsilateral dentate gyrus, corpus callosum, thalami and injury penumbra of injured animals compared to sham animals. PBR co-stained with amoeboid microglia/macrophages in the injury penumbra and not with astrocytes. These data suggest the technologies evaluated may serve as bio-signatures of neuroinflammation following severe brain injury in small animals, potentially enabling in vivo tracking of neuroinflammation following TBI and cellular-based therapies.

The only available option to treat radiation-induced hematopoietic syndrome is allogeneic hematopoietic cell transplantation, a therapy unavailable to many patients undergoing treatment for malignancy, which would also be infeasible in a radiological disaster. Stromal cells serve as critical components of the hematopoietic stem cell niche and are thought to protect hematopoietic cells under stress. Prior studies that have transplanted mesenchymal stromal cells (MSCs) without co-administration of a hematopoietic graft have shown underwhelming rescue of endogenous hematopoiesis and have delivered the cells within 24 h of radiation exposure. Herein, we examine the efficacy of a human bone marrow-derived MSC therapy delivered at 3 h or 30 h in ameliorating radiation-induced hematopoietic syndrome and show that pancytopenia persists despite MSC therapy. Animals exposed to radiation had poorer survival and experienced loss of leukocytes, platelets, and red blood cells. Importantly, mice that received a therapeutic dose of MSCs were significantly less likely to die but experienced equivalent collapse of the hematopoietic system. The cause of the improved survival was unclear, as complete blood counts, splenic and marrow cellularity, numbers and function of hematopoietic stem and progenitor cells, and frequency of niche cells were not significantly improved by MSC therapy. Moreover, human MSCs were not detected in the bone marrow. MSC therapy reduced crypt dropout in the small intestine and promoted elevated expression of growth factors with established roles in gut development and regeneration, including PDGF-A, IGFBP-3, IGFBP-2, and IGF-1. We conclude that MSC therapy improves survival not through overt hematopoietic rescue but by positive impact on other radiosensitive tissues, such as the intestinal mucosa. Collectively, these data reveal that MSCs could be an effective countermeasure in cancer patients and victims of nuclear accidents but that MSCs alone do not significantly accelerate or contribute to recovery of the blood system.

Objective: Abnormal pulmonary vasculature directly affects the development and progression of congenital diaphragmatic hernia (CDH)-associated pulmonary hypertension (PH). Though overarching structural and cellular changes in CDH-affected pulmonary arteries have been documented, the precise role of the extracellular matrix (ECM) in the pulmonary artery (PA) pathophysiology remains undefined. Here, we quantify the structural, compositional, and mechanical CDH-induced changes in the main and distal PA ECM and investigate the efficacy of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) as a therapy to ameliorate pathological vascular ECM changes., Methods: Pregnant Sprague-Dawley rodents were administered nitrofen to induce CDH-affected pulmonary vasculature in the offspring. A portion of CDH-affected pups was treated with intravenous infusion of MSC-EVs (1 × 10 10 /mL) upon birth. A suite of histological, mechanical, and transmission electron microscopic analyses were utilized to characterize the PA ECM., Results: The CDH model main PA presented significantly altered characteristics-including greater vessel thickness, greater lysyl oxidase (LOX) expression, and a relatively lower ultimate tensile strength of 13.6 MPa compared to control tissue (25.1 MPa), suggesting that CDH incurs ECM structural disorganization. MSC-EV treatment demonstrated the potential to reverse CDH-related changes, particularly through rapid inhibition of ECM remodeling enzymes (LOX and MMP-9). Additionally, MSC-EV treatment bolstered structural aspects of the PA ECM and mitigated pathological disorganization as exhibited by increased medial wall thickness and stiffness that, while not significantly altered, trends away from CDH-affected tissue., Conclusions: These data demonstrate notable ECM remodeling in the CDH pulmonary vasculature, along with the capacity of MSC-EVs to attenuate pathological ECM remodeling, identifying MSC-EVs as a potentially efficacious therapeutic for CDH-associated pulmonary hypertension., (© 2020 Wiley Periodicals LLC.)