Introduction

CHRFAM7A is a uniquely-human gene that encodes a human-specific variant of the alpha-7 nicotinic acetylcholine receptor (α7nAchR). While the homopentameric α7nAChR consists of 5 equal subunits, previous studies demonstrated that CHRFAM7A expression disrupts the formation of α7nAChR homopentamers. Here we use a rat neuronal cell line expressing CHRFAM7A and a transgenic mouse expressing CHRFAM7A to define the alpha-bungarotoxin (α-BTX) binding in vitro and in vivo.

Methods

Rat PC12 cells were stably transfected with human CHRFAM7A. α-BTX, a protein that irreversibly binds the α7nAchR, was utilized to assess the capacity for CHRFAM7A to interfere with α 7AchR subunits using immunohistochemistry and flow cytometry. To evaluate the effects of CHRFAM7A on α7nAchR at the neuromuscular junction in vivo, transgenic mice were engineered to express the uniquely human gene CHRFAM7A under the control of the EF1-α promoter. Using this model, muscle was harvested and CHRFAM7A and CHRNA7 gene expression evaluated by PCR. Binding of α-BTX to the α7nAchR in muscle was compared in sibling-matched wild-type C57 mice by immunostaining the neuromuscular junction using α-BTX and neurofilament antibodies.

Results

Expression of CHRFAM7A in transfected, but not vector cells, was confirmed by PCR and by immunoblotting using an antibody we raised to a peptide sequence unique to CHRFAM7A. CHRFAM7A decreased α-BTX binding as detected by immunohistochemistry and flow cytometry. In vivo, α-BTX co-stained with neurofilament at the neuromuscular junction in wild-type mice, however, α-BTX staining was decreased at the neuromuscular junction of CHRFAM7A transgenic mice.

Conclusion

CHRFAM7A expression interferes with the binding of α7nAchR to α-BTX. Understanding the contribution of this uniquely human gene to human disease will be important in the identification of potential therapeutic targets.

Background

Trauma/hemorrhagic shock (T/HS) causes a release of proinflammatory mediators into the mesenteric lymph (ML) that may trigger a systemic inflammatory response and subsequent organ failure. Recently, we showed that exosomes in postshock ML are biologically active mediators of this inflammation. Because the specific inflammatory mediators in postshock ML exosomes have yet to be characterized, we hypothesized that T/HS would lead to a distinct ML proinflammatory exosome phenotype that could be identified by proteomic analysis. We further hypothesized that their regulation by the neuroenteric axis via the vagus nerve would modify this proinflammatory profile.

Methods

Male rats underwent an established T/HS model including 60 minutes of HS followed by resuscitation. Mesenteric lymph was collected before HS (preshock) and after resuscitation (postshock). A subset of animals underwent cervical vagus nerve electrical stimulation (VNS) after the HS phase. Liquid chromatography with tandem mass spectroscopy (LC-MS/MS) followed by protein identification, label free quantification, and bioinformatic analysis was performed on exosomes from the pre-shock and post-shock phases in the T/HS and T/HS + vagus nerve electrical stimulation groups. Biological activity of exosomes was evaluated using a monocyte nuclear factor kappa B (NF-κB) activity assay.

Results

ML exosomes express a distinct protein profile after T/HS with enrichment in pathways associated with cell signaling, cell death and survival, and the inflammatory response. Stimulation of the vagus nerve following injury attenuated the transition of ML exosomes to this T/HS-induced inflammatory phenotype with protein expression remaining similar to pre-shock. Monocyte NF-κB activity was increased after exposure to ML exosomes harvested after T/HS, while ML exosomes from preshock had no effect on monocyte NF-κB expression.

Conclusion

Postshock ML exosomes carry a distinct, proinflammatory protein cargo. Stimulating the vagus nerve prevents the T/HS-induced changes in ML exosome protein payload and suggests a novel mechanism by which the neuroenteric axis may limit the systemic inflammatory response after injury.

Introduction

The analysis of surgical research using bibliometric measures has become increasingly prevalent. Absolute citation counts (CC) or indices are commonly used markers of research quality but may not adequately capture the most impactful research. A novel scoring system, the disruptive score (DS) has been found to identity academic work that either changes paradigms (disruptive (DIS) work) or entrenches ideas (developmental (DEV) work). We sought to analyze the most DIS and DEV versus most cited research in civilian trauma.

Methods

The top papers by DS and by CC from trauma and surgery journals were identified via a professional literature search. The identified publications were then linked to the National Institutes of Health iCite tool to quantify total CC and related metrics. The top 100 DIS and DEV publications by DS were analyzed based on the area of focus, citation, and perceived clinical impact, and compared with the top 100 papers by CC.

Results

32 293 articles published between 1954 and 2014 were identified. The most common publication location of selected articles was published in Journal of Trauma (31%). Retrospective reviews (73%) were common in DIS (73%) and top CC (67%) papers, while DEV papers were frequently case reports (49%). Only 1 publication was identified in the top 100 DIS and top 100 CC lists. There was no significant correlation between CC and DS among the top 100 DIS papers (r=0.02; p=0.85), and only a weak correlation between CC and DS score (r=0.21; p<0.05) among the top 100 DEV papers.

Conclusion

The disruption score identifies a unique subset of trauma academia. The most DIS trauma literature is highly distinct and has little overlap with top trauma publications identified by standard CC metrics, with no significant correlation between the CC and DS.

Level of evidence

Level IV.

A subset of genes in the human genome are uniquely human and not found in other species. One example is CHRFAM7A, a dominant-negative inhibitor of the antiinflammatory α7 nicotinic acetylcholine receptor (α7nAChR/CHRNA7) that is also a neurotransmitter receptor linked to cognitive function, mental health, and neurodegenerative disease. Here we show that CHRFAM7A blocks ligand binding to both mouse and human α7nAChR, and hypothesized that CHRFAM7A-transgenic mice would allow us to study its biological significance in a tractable animal model of human inflammatory disease, namely SIRS, the systemic inflammatory response syndrome that accompanies severe injury and sepsis. We found that CHRFAM7A increased the hematopoietic stem cell (HSC) reservoir in bone marrow and biased HSC differentiation to the monocyte lineage in vitro. We also observed that while the HSC reservoir was depleted in SIRS, HSCs were spared in CHRFAM7A-transgenic mice and that these mice also had increased immune cell mobilization, myeloid cell differentiation, and a shift to inflammatory monocytes from granulocytes in their inflamed lungs. Together, the findings point to a pathophysiological inflammatory consequence to the emergence of CHRFAM7A in the human genome. To this end, it is interesting to speculate that human genes like CHRFAM7A can account for discrepancies between the effectiveness of drugs like α7nAChR agonists in animal models and human clinical trials for inflammatory and neurodegenerative disease. The findings also support the hypothesis that uniquely human genes may be contributing to underrecognized human-specific differences in resiliency/susceptibility to complications of injury, infection, and inflammation, not to mention the onset of neurodegenerative disease.

Background

Bibliometric analysis of surgical research has become increasingly prevalent. Citation count (CC) is a commonly used marker of research quality, but may overlook impactful military research. The disruption score (DS) evaluates manuscripts on a spectrum from most innovative with more positive scores (disruptive [DR]) to most entrenched with more negative scores (developmental; DV). We sought to analyze the most DR and DV versus most cited research in military trauma.

Methods

Top trauma articles by DS and by CC were identified via professional literature search. All publications in military journals were included. Military trauma-related keywords were used to query additional top surgical journals for military-focused publications. Publications were linked to the iCite NIH tool for CC and related metrics. The top 100 DR and DV publications by DS were analyzed and compared with the top 100 articles by CC.

Results

Overall, 32,040 articles published between 1954 and 2014 were identified. The average DS and CC were 0.01 and 22, respectively. Most articles were published in Mil Med ( 68%). The top 100 DR articles were frequently published in Mil Med (51%) with a mean DS of 0.148. Of these, the most cited article was only the 40th most disruptive. The top 100 CC articles averaged a DS of 0.009 and were commonly found in J Trauma (53%). Only five publications were on both the top 100 DR and top 100 CC lists; 19 were on both the top DV and CC lists. Citation count was not correlated with DR ( r = -0.134; p = 0.07) and only weakly correlated with DV ( r = 0.215; p = 0.003).

Conclusion

DS identifies publications that changed military paradigms and future research directions previously overlooked by citation count alone. The DR and DV articles are distinct with little overlap between highly cited military articles. Multiple bibliometric measures should be employed to avoid overlooking impactful military trauma research.

Level of evidence

Diagnostic Test or Criteria; Level IV.

BACKGROUND: Posttraumatic venous thromboembolism (VTE) remains prevalent in severely injured patients despite chemoprophylaxis. Importantly, although platelets are central to thrombosis, they are not routinely targeted in prevention of posttraumatic VTE. Furthermore, platelets from injured patients show ex vivo evidence of increased activation yet impaired aggregation, consistent with functional exhaustion. However, the relationship of this platelet functional phenotype with development of posttraumatic VTE is unknown. We hypothesized that, following injury, impaired ex vivo platelet aggregation (PA) is associated with the development of posttraumatic VTE. METHODS: We performed a secondary analysis of 133 severely injured patients from a prospective observational study investigating coagulation and inflammation (2011-2019). Platelet aggregation in response to stimulation with adenosine diphosphate (ADP), collagen, and thrombin was measured at presentation (preresuscitation) and 24 hours (postresuscitation). Viscoelastic clot strength and lysis were measured in parallel by thromboelastography. Multivariable regression examined relationships between PA at presentation, 24 hours, and the change (δ) in PA between presentation and 24 hours with development of VTE. RESULTS: The 133 patients were severely injured (median Injury Severity Score, 25), and 14% developed VTE (all >48 hours after admission). At presentation, platelet count and PA were not significantly different between those with and without incident VTE. However, at 24 hours, those who subsequently developed VTE had significantly lower platelet counts (126 × 10 9 /L vs. 164 × 10 9 /L, p = 0.01) and lower PA in response to ADP ( p < 0.05), collagen ( p < 0.05), and thrombin ( p = 0.06). Importantly, the magnitude of decrease in PA (δ) from presentation to 24 hours was independently associated with development of VTE (adjusted odds ratios per 10 aggregation unit decrease: δ-ADP, 1.31 [ p = 0.03]; δ-collagen, 1.36 [ p = 0.01]; δ-thrombin, 1.41 [ p < 0.01]). CONCLUSION: Severely injured patients with decreasing ex vivo measures of PA despite resuscitation have an increased risk of developing VTE. This may have implications for predicting development of VTE and for studying platelet targeted chemoprophylaxis regimens. LEVEL OF EVIDENCE: Prognostic/Epidemiological; Level III.

Introduction

Since their release in 2017, standing electric motorized scooters (eScooters) have risen in popularity as an alternative mode of transportation. We sought to examine the incidence of injury, injury patterns, prevalence of helmet and drug and alcohol use in eScooter trauma.

Methods

This was a multi-institutional retrospective case series of patients admitted for injuries related to operation of an eScooter following the widespread release of these devices in September 2017 (September 1, 2017 to October 31, 2018). Demographics, drug and alcohol use, helmet use, admission vitals, injuries, procedures, hospital and intensive care unit length of stay (LOS), death, and disposition were analyzed.

Results

103 patients were admitted during the study period, and monthly admissions increased significantly over time. Patients were young men (mean age 37.1 years; 65% male), 98% were not wearing a helmet. Median LOS was 1 day (IQR 1-3). 79% of patients were tested for alcohol and 48% had a blood alcohol level >80 mg/dL. 60% of patients had a urine toxicology screen, of which 52% were positive. Extremity fractures were the most frequent injury (42%), followed by facial fractures (26%) and intracranial hemorrhage (18%). Median Injury Severity Score was 5.5 (IQR 5-9). One-third of patients (n=34) required an operative intervention, the majority of which were open fixations of extremity and facial fractures. No patients died during the study. The majority of patients were discharged home (86%).

Conclusion

eScooter-related trauma has significantly increased over time. Alcohol and illicit substance use among these patients was common, and helmet use was extremely rare. Significant injuries including intracranial hemorrhage and fractures requiring operative intervention were present in over half (51%) of patients. Interventions aimed at increasing helmet use and discouraging eScooter operation while intoxicated are necessary to reduce the burden of eScooter-related trauma.

Level of evidence

Level IV.

Given the evidence for a hyperactive platelet phenotype in COVID-19, we investigated effector cell properties of COVID-19 platelets on endothelial cells (ECs). Integration of EC and platelet RNA sequencing revealed that platelet-released factors in COVID-19 promote an inflammatory hypercoagulable endotheliopathy. We identified S100A8 and S100A9 as transcripts enriched in COVID-19 platelets and were induced by megakaryocyte infection with SARS-CoV-2. Consistent with increased gene expression, the heterodimer protein product of S100A8/A9, myeloid-related protein (MRP) 8/14, was released to a greater extent by platelets from COVID-19 patients relative to controls. We demonstrate that platelet-derived MRP8/14 activates ECs, promotes an inflammatory hypercoagulable phenotype, and is a significant contributor to poor clinical outcomes in COVID-19 patients. Last, we present evidence that targeting platelet P2Y₁₂ represents a promising candidate to reduce proinflammatory platelet-endothelial interactions. Together, these findings demonstrate a previously unappreciated role for platelets and their activation-induced endotheliopathy in COVID-19.