What do Trauma Surgery Textbooks Teach About Racial Disparities and the Roots of Violence?

This study presents a formal text analysis of trauma surgery textbooks. We examine passages that describe disparities or mechanisms of injury, and we report types of underlying causes and preventative interventions discussed. Trauma textbooks were drawn from an industry-standard list used by medical libraries. Chi-square testing was used to determine whether different types of underlying causes or preventative interventions were discussed by disparity type (those affecting racial minorities vs rural populations) and injury mechanism (accidental injuries vs intentional interpersonal injury). 146 passages were extracted from 7 textbooks, totaling 5576 pages of text. Passages discussing rural disadvantages or unintentional injury were substantially more likely to describe structural risk factors or governmental interventions than those discussing racial disadvantages or intentional injury, respectively. Textbook authors should consider enriching discussion of violence prevention or racial disparities to emphasize structural causes and interventions.

Safety of lung cancer surgery during COVID-19 in a pandemic epicenter.

BACKGROUND: The influence of SARS-CoV-2 on surgery for non-small cell lung cancer needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. OBJECTIVE: This study reports on the 90-day rate of infection as well as the morbidity and mortality of lung surgery for cancer in a tertiary care hospital located in a pandemic epicenter. METHODS: We conducted a retrospective review of a prospective database to identify consecutive patients who underwent lung cancer resection before (January 1, 2020-March 10, 2020, group 1; 57 patients) and during the COVID-19 pandemic (March 11, 2020-June 10, 2020, group 2; 41 patients). The primary end point was the occurrence of SARS-CoV-2 infection during the first 90-days after surgery. The secondary outcome measure was 90-day perioperative morbidity and mortality. RESULTS: Patient characteristics were not significantly different between the groups. Ninety-day COVID-19 infection rates was 7.3% (3 out of 41) for patients undergoing an operation during the pandemic and 3.5% (2 out of 57) in patients operated on immediately before the pandemic. All patients tested positive 10 to 62 days after the index surgical procedure following hospital discharge. Four COVID-19-positive patients were symptomatic and 4 out of 5 patients required hospitalization, were men, previous or current smokers with hyperlipidemia, and underwent a sublobar resection. Univariate analysis did not identify any differences in postoperative complications before or during the COVID-19 pandemic. Ninety-day mortality was 5% (2 out of 41) for lung cancer surgery performed during the pandemic, with all deaths occurring due to COVID-19, compared with 0% (0 out of 57) mortality in patients who underwent an operation before the pandemic. CONCLUSIONS: During the COVID-19 pandemic, COVID-19 infections occurred in 7.3% of patients who underwent surgery for non-small cell lung cancer. In this series all infections occurred after hospital discharge. Our results suggest that COVID-19 infections occurring within 90 days of surgery portend a 40% mortality, warranting close postoperative surveillance.

Endothelial Targeted Strategies to Combat Oxidative Stress: Improving Outcomes in Traumatic Brain Injury.

The endothelium is a thin monolayer of specialized cells that lines the luminal wall of blood vessels and constitutes the critical innermost portion of the physical barrier between the blood and the brain termed the blood-brain barrier (BBB). Aberrant changes in the endothelium occur in many neuropathological states, including those with high morbidity and mortality that lack targeted therapeutic interventions, such as traumatic brain injury (TBI). Utilizing ligands of surface determinants expressed on brain endothelium to target and combat injury mechanisms at damaged endothelium offers a new approach to the study of TBI and new avenues for clinical advancement. Many factors influence the targets that are expressed on endothelium. Therefore, the optimization of binding sites and ideal design features of nanocarriers are controllable factors that permit the engineering of nanotherapeutic agents with applicability that is specific to a known disease state. Following TBI, damaged endothelial cells upregulate cell adhesion molecules, including ICAM-1, and are key sites of reactive oxygen species (ROS) generation, including hydrogen peroxide. Reactive oxygen species along with pro-inflammatory mediators are known to contribute to endothelial damage and loss of BBB integrity. The use of targeted endothelial nanomedicine, with conjugates of the antioxidant enzyme catalase linked to anti-ICAM-1 antibodies, has recently been demonstrated to minimize oxidative stress at the BBB and reduce neuropathological outcomes following TBI. Here, we discuss targeted endothelial nanomedicine and its potential to provide benefits in TBI outcomes and future directions of this approach.

Characterization of cancer-associated IDH2 mutations that differ in tumorigenicity, chemosensitivity and 2-hydroxyglutarate production.

The family of isocitrate dehydrogenase (IDH) enzymes is vital for cellular metabolism, as IDH1 and IDH2 are required for the decarboxylation of isocitrate to α-ketoglutarate. Heterozygous somatic mutations in IDH1 or IDH2 genes have been detected in many cancers. They share the neomorphic production of the oncometabolite (R)-2-hydroxyglutarate [(R)-2-HG]. With respect to IDH2, it is unclear whether all IDH2 mutations display the same or differ in tumorigenic properties and degrees of chemosensitivity. Here, we evaluated the three most frequent IDH2 mutations occurring in cancer. The predicted changes to the enzyme structure introduced by these individual mutations are supported by the observed production of (R)-2-HG. However, their tumorigenic properties, response to chemotherapeutic agents, and baseline activation of STAT3 differed. Paradoxically, the varying levels of endogenous (R)-2-HG produced by each IDH2 mutant inversely correlated with their respective growth rates. Interestingly, while we found that (R)-2-HG stimulated the growth of non-transformed cells, (R)-2-HG also displayed antitumor activity by suppressing the growth of tumors harboring wild type IDH2. The mitogenic effect of (R)-2-HG in immortalized cells could be switched to antiproliferative by transformation with oncogenic RAS. Thus, our findings show that despite their shared (R)-2-HG production, IDH2 mutations are not alike and differ in shaping tumor cell behavior and response to chemotherapeutic agents. Our study also reveals that under certain conditions, (R)-2-HG has antitumor properties.

Characterization of human fetal brain endothelial cells reveals barrier properties suitable for in vitro modeling of the BBB with syngenic co-cultures.

Endothelial cells (ECs) form the basis of the blood-brain barrier (BBB), a physical barrier that selectively restricts transport into the brain. In vitro models can provide significant insight into BBB physiology, mechanisms of human disease pathology, toxicology, and drug delivery. Given the limited availability of primary human adult brain microvascular ECs ( aBMVECs), human fetal tissue offers a plausible alternative source for multiple donors and the opportunity to build syngenic tri-cultures from the same host. Previous efforts to culture fetal brain microvascular ECs ( fBMVECs) have not been successful in establishing mature barrier properties. Using optimal gestational age for isolation and flow cytometry cell sorting, we show for the first time that fBMVECs demonstrate mature barrier properties. fBMVECs exhibited similar functional phenotypes when compared to aBMVECs for barrier integrity, endothelial activation, and gene/protein expression of tight junction proteins and transporters. Importantly, we show that tissue used to culture fBMVECs can also be used to generate a syngenic co-culture, creating a microfluidic BBB on a chip. The findings presented provide a means to overcome previous challenges that limited successful barrier formation by fBMVECs. Furthermore, the source is advantageous for autologous reconstitution of the neurovascular unit for next generation in vitro BBB modeling.

Dexamethasone Attenuates the Enhanced Rewarding Effects of Cocaine Following Experimental Traumatic Brain Injury.

Clinical studies have identified traumatic brain injury (TBI) as a risk factor for the development of cocaine dependence. This claim is supported by our recent preclinical studies showing enhancement of the rewarding effects of cocaine in mice sustaining moderate controlled cortical impact (CCI) injury during adolescence. Here we test the efficacy of dexamethasone, an anti-inflammatory corticosteroid, to attenuate augmentation of the behavioral response to cocaine observed in CCI-TBI animals using the conditioned place preference (CPP) assay. These studies were performed in order to determine whether proinflammatory activity in the nucleus accumbens (NAc), a key brain nucleus in the reward pathway, mediates enhanced cocaine-induced CPP in adolescent animals sustaining moderate CCI-TBI. Our data reveal robust glial activation in the NAc following CCI-TBI and a significant increase in the cocaine-induced CPP of untreated CCI-TBI mice. Furthermore, our results show that dexamethasone treatment following CCI-TBI can attenuate the cocaine place preference of injured animals without producing aversion in the CPP assay. Our studies also found that dexamethasone treatment significantly reduced the expression of select immune response genes including Monocyte chemoattractant protein-1 (MCP-1/CCL2) and intercellular adhesion molecule-1 ( ICAM-1), returning their expression to control levels, which prompted an investigation of peripheral blood monocytes in dexamethasone-treated animals. Experimental findings showed that no craniectomy/dexamethasone mice had a significant increase, while CCI-TBI/dexamethasone animals had a significant decrease in the percentage of circulating nonclassical patrolling monocytes. These results suggest that a portion of these monocytes may migrate to the brain in response to CCI-TBI, potentially sparing the development of chronic neuroinflammation in regions associated with the reward circuitry such as the NAc. Overall, our findings indicate that anti-inflammatory agents, such as dexamethasone, may be effective in normalizing the rewarding effects of cocaine following CCI-TBI.

Acute administration of catalase targeted to ICAM-1 attenuates neuropathology in experimental traumatic brain injury.

Traumatic brain injury (TBI) contributes to one third of injury related deaths in the US. Treatment strategies for TBI are supportive, and the pathophysiology is not fully understood. Secondary mechanisms of injury in TBI, such as oxidative stress and inflammation, are points at which intervention may reduce neuropathology. Evidence suggests that reactive oxygen species (ROS) propagate blood-brain barrier (BBB) hyperpermeability and inflammation following TBI. We hypothesized that targeted detoxification of ROS may improve the pathological outcomes of TBI. Following TBI, endothelial activation results in a time dependent increase in vascular expression of ICAM-1. We conjugated catalase to anti-ICAM-1 antibodies and administered the conjugate to 8 wk old C57BL/6J mice 30 min after moderate controlled cortical impact injury. Results indicate that catalase targeted to ICAM-1 reduces markers of oxidative stress, preserves BBB permeability, and attenuates neuropathological indices more effectively than non-targeted catalase and anti-ICAM-1 antibody alone. Furthermore, the study of microglia by two-photon microscopy revealed that anti-ICAM-1/catalase prevents the transition of microglia to an activated phenotype. These findings demonstrate the use of a targeted antioxidant enzyme to interfere with oxidative stress mechanisms in TBI and provide a proof-of-concept approach to improve acute TBI management that may also be applicable to other neuroinflammatory conditions.

Factors affecting increased risk for substance use disorders following traumatic brain injury: What we can learn from animal models.

Recent studies have helped identify multiple factors affecting increased risk for substance use disorders (SUDs) following traumatic brain injury (TBI). These factors include age at the time of injury, repetitive injury and TBI severity, neurocircuits, neurotransmitter systems, neuroinflammation, and sex differences. This review will address each of these factors by discussing 1) the clinical and preclinical data identifying patient populations at greatest risk for SUDs post-TBI, 2) TBI-related neuropathology in discrete brain regions heavily implicated in SUDs, and 3) the effects of TBI on molecular mechanisms that may drive substance abuse behavior, like dopaminergic and glutamatergic transmission or neuroimmune signaling in mesolimbic regions of the brain. Although these studies have laid the groundwork for identifying factors that affect risk of SUDs post-TBI, additional studies are required. Notably, preclinical models have been shown to recapitulate many of the behavioral, cellular, and neurochemical features of SUDs and TBI. Therefore, these models are well suited for answering important questions that remain in future investigations.

Adolescent Traumatic Brain Injury Induces Chronic Mesolimbic Neuroinflammation with Concurrent Enhancement in the Rewarding Effects of Cocaine in Mice during Adulthood.

Clinical psychiatric disorders of depression, anxiety, and substance abuse are most prevalent after traumatic brain injury (TBI). Pre-clinical research has focused on depression and anxiety post-injury; however, virtually no data exist examining whether the preference for illicit drugs is affected by traumatic injury in the developing adolescent brain. Using the controlled cortical impact (CCI) model of TBI and the conditioned place preference (CPP) assay, we tested the underlying hypothesis that brain injury during adolescence exacerbates the rewarding properties of cocaine in adulthood possibly through an active inflammatory status in the mesolimbic pathway. Six-week old, C57BL/6 mice sustained a single CCI-TBI to the right somatosensory cortex. CPP experiments with cocaine began 2 weeks post-TBI. Animals receiving cocaine displayed significant place preference shifts compared to saline controls. Further, within the cocaine-experienced cohort, moderate CCI-TBI during adolescence significantly increased the preference shift in adulthood when compared to naïve controls. Additionally, persistent neuroinflammatory responses were observed in the cortex, nucleus accumbens (NAc), and ventral tegmental area post-CCI-TBI. Significant increases in both astrocytic, glial fibrillary acidic protein, and microglial, ionization basic acid 1, markers were observed in the NAc at the end of CPP testing. Moreover, analysis using focused array gene expression panels identified the upregulation of numerous inflammatory genes in moderate CCI-TBI animals, compared to naïve controls, both in the cortex and NAc at 2 weeks post-TBI, before onset of cocaine administration. These results suggest that sustaining moderate TBI during adolescence may augment the rewarding effects of psychostimulants in adulthood, possibly by induction of chronic mesolimbic neuroinflammation.

Trafficking of adeno-associated virus vectors across a model of the blood-brain barrier; a comparative study of transcytosis and transduction using primary human brain endothelial cells.

Developing therapies for central nervous system (CNS) diseases is exceedingly difficult because of the blood-brain barrier (BBB). Notably, emerging technologies may provide promising new options for the treatment of CNS disorders. Adeno-associated virus serotype 9 (AAV9) has been shown to transduce cells in the CNS following intravascular administration in rodents, cats, pigs, and non-human primates. These results suggest that AAV9 is capable of crossing the BBB. However, mechanisms that govern AAV9 transendothelial trafficking at the BBB remain unknown. Furthermore, possibilities that AAV9 may transduce brain endothelial cells or affect BBB integrity still require investigation. Using primary human brain microvascular endothelial cells as a model of the human BBB, we performed transduction and transendothelial trafficking assays comparing AAV9 to AAV2, a serotype that does not cross the BBB or transduce endothelial cells effectively in vivo. Results of our in vitro studies indicate that AAV9 penetrates brain microvascular endothelial cells barriers more effectively than AAV2, but has reduced transduction efficiency. In addition, our data suggest that (i) AAV9 penetrates endothelial barriers through an active, cell-mediated process, and (ii) AAV9 fails to disrupt indicators of BBB integrity such as transendothelial electrical resistance, tight junction protein expression/localization, and inflammatory activation status. Overall, this report shows how human brain endothelial cells configured in BBB models can be utilized for evaluating transendothelial movement and transduction kinetics of various AAV capsids. Importantly, the use of a human in vitro BBB model can provide import insight into the possible effects that candidate AVV gene therapy vectors may have on the status of BBB integrity. Read the Editorial Highlight for this article on page 192.

Mechanical Injury Induces Brain Endothelial-Derived Microvesicle Release: Implications for Cerebral Vascular Injury during Traumatic Brain Injury.

It is well established that the endothelium responds to mechanical forces induced by changes in shear stress and strain. However, our understanding of vascular remodeling following traumatic brain injury (TBI) remains incomplete. Recently published studies have revealed that lung and umbilical endothelial cells produce extracellular microvesicles (eMVs), such as microparticles, in response to changes in mechanical forces (blood flow and mechanical injury). Yet, to date, no studies have shown whether brain endothelial cells produce eMVs following TBI. The brain endothelium is highly specialized and forms the blood-brain barrier (BBB), which regulates diffusion and transport of solutes into the brain. This specialization is largely due to the presence of tight junction proteins (TJPs) between neighboring endothelial cells. Following TBI, a breakdown in tight junction complexes at the BBB leads to increased permeability, which greatly contributes to the secondary phase of injury. We have therefore tested the hypothesis that brain endothelium responds to mechanical injury, by producing eMVs that contain brain endothelial proteins, specifically TJPs. In our study, primary human adult brain microvascular endothelial cells (BMVEC) were subjected to rapid mechanical injury to simulate the abrupt endothelial disruption that can occur in the primary injury phase of TBI. eMVs were isolated from the media following injury at 2, 6, 24, and 48 h. Western blot analysis of eMVs demonstrated a time-dependent increase in TJP occludin, PECAM-1 and ICAM-1 following mechanical injury. In addition, activation of ARF6, a small GTPase linked to extracellular vesicle production, was increased after injury. To confirm these results in vivo, mice were subjected to sham surgery or TBI and blood plasma was collected 24 h post-injury. Isolation and analysis of eMVs from blood plasma using cryo-EM and flow cytometry revealed elevated levels of vesicles containing occludin following brain trauma. These results indicate that following TBI, the cerebral endothelium undergoes vascular remodeling through shedding of eMVs containing TJPs and endothelial markers. The detection of this shedding potentially allows for a novel methodology for real-time monitoring of cerebral vascular health (remodeling), BBB status and neuroinflammation following a TBI event.

The effects of fluid injection on lesion size during bipolar radiofrequency treatment.

BACKGROUND: The effect of preinjected fluid on bipolar radiofrequency (RF) lesion characteristics has not been investigated with conventional pain medicine equipment. The purpose of the present study was to determine the effect of preinjected fluid composition on lesion parameters. METHODS: Bipolar RF lesioning was performed in ex vivo chicken samples without fluid preinjection or with 0.7 mL of fluid injected through the 2 RF cannulas (total volume, 1.4 mL). The preinjected fluids were sterile water, 0.9% NaCl, 3% NaCl, 1% lidocaine, and 6% hydroxyethyl starch (HES). For each condition, RF electrodes were incrementally separated, and the number of trials producing successful lesions was recorded. Maximum and minimum height, length, and depth of the lesions were measured, and volumes of the lesions were calculated. RESULTS: The preinjection of any fluid increased the odds of consistently achieving a continuous lesion between the electrodes that was at least 75% of the maximal height of tissue damaged; 3% NaCl increased the odds of achieving at least 75% maximum height significantly more than any other fluid except for HES. Injection of any fluid containing NaCl (including lidocaine and HES) significantly increased the mean volume of tissue lesioned over that observed with injection of water. CONCLUSIONS: Fluid composition influences success, alters lesion size, and could be an appropriate consideration when selecting treatment parameters for bipolar RF. The enhanced lesion size and improved odds of producing a successful lesion with increasing NaCl concentration suggest a method to enlarge lesion size in a controlled manner.

Spinal cord stimulation utilization to treat the microcirculatory vascular insufficiency and ulcers associated with scleroderma: a case report and review of the literature.

OBJECTIVE: To report a case of scleroderma with associated Raynaud's phenomenon and its successful treatment with spinal cord stimulation. To demonstrate the use of transcutaneous oxygen pressure monitoring to guide the progression from trial to implantation and to assess post-implantation microcirculatory recovery. DESIGN: Case report and literature review. PATIENT: A 51-year-old female with scleroderma, associated Raynaud's phenomenon, and a non-healing 3.7-cm lower extremity ischemic ulcer. Ankle-brachial indexes demonstrated normal macrocirculation, but transcutaneous oxygen pressures demonstrated significant microcirculatory insufficiency. INTERVENTION: Treatment was a spinal cord stimulator implantation after a successful trial. Transcutaneous oxygen pressures were interpreted during the trial and post-implantation stages. Results. Based on a 5-day trial that documented improvements in transcutaneous oxygen pressures and pain relief, the patient underwent implantation. At 4 months, the ischemic ulcer had healed. The patient had significant improvement in pain control and reduced Raynaud's phenomenon signs and symptoms. At 18 months, the patient continued to have improvement with no associated complications. A literature review demonstrated only four published reports, including a total of 18 patients, on spinal cord stimulator treatment for scleroderma and associated Raynaud's phenomenon. CONCLUSIONS: We report the healing of a greater than 3-cm ischemic ulcer in an individual with normal macrocirculation but severe microcirculatory insufficiency from scleroderma. Improvements in microcirculation correlated with wound healing. Spinal cord stimulation may be considered for select individuals with microcirculatory reserves that can be modulated with treatment.