Omics markers of platelet transfusion in trauma patients

Trauma patients with type O blood exhibit unique multiomics signature with decreased lectin pathway of complement levels

BACKGROUND

Patients with type O blood may have an increased risk of hemorrhagic complications because of lower baseline levels of von Willebrand factor and factor VIII, but the transition to a mortality difference in trauma is less clear. We hypothesized that type O trauma patients will have differential proteomic and metabolomic signatures in response to trauma beyond von Willebrand factor and factor VIII alone.

METHODS

Patients meeting the highest level of trauma activation criteria were prospectively enrolled. Blood samples were collected upon arrival to the emergency department. Proteomic and metabolomic (multiomics) analyses of these samples were performed using liquid chromatography-mass spectrometry. Demographic, clinical, and multiomics data were compared between patients with type O blood versus all other patients.

RESULTS

There were 288 patients with multiomics data; 146 (51%) had type O blood. Demographics, injury patterns, and initial vital signs and laboratory measurements were not different between groups. Type O patients had increased lengths of stay (7 vs. 6 days, p = 0.041) and a trend toward decreased mortality secondary to traumatic brain injury compared with other causes (traumatic brain injury, 44.4% vs. 87.5%; p = 0.055). Type O patients had decreased levels of mannose-binding lectin and mannose-binding lectin-associated serine proteases 1 and 2, which are required for the initiation of the lectin pathway of complement activation. Type O patients also had metabolite differences signifying energy metabolism and mitochondrial dysfunction.

CONCLUSION

Blood type O patients have a unique multiomics signature, including decreased levels of proteins required to activate the lectin complement pathway. This may lead to overall decreased levels of complement activation and decreased systemic inflammation in the acute phase, possibly leading to a survival advantage, especially in traumatic brain injury. However, this may later impair healing. Future work will need to confirm these associations, and animal studies are needed to test therapeutic targets.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Platelet releasates mitigate the endotheliopathy of trauma

BACKGROUND

Platelets are well known for their roles in hemostasis, but they also play a key role in thromboinflammatory pathways by regulating endothelial health, stimulating angiogenesis, and mediating host defense through both contact dependent and independent signaling. When activated, platelets degranulate releasing multiple active substances. We hypothesized that the soluble environment formed by trauma platelet releasates (TPR) attenuates thromboinflammation via mitigation of trauma induced endothelial permeability and metabolomic reprogramming.

METHODS

Blood was collected from injured and healthy patients to generate platelet releasates and plasma in parallel. Permeability of endothelial cells when exposed to TPR and plasma (TP) was assessed via resistance measurement by electric cell-substrate impedance sensing (ECIS). Endothelial cells treated with TPR and TP were subjected to mass spectrometry-based metabolomics.

RESULTS

TP increased endothelial permeability, whereas TPR decreased endothelial permeability when compared with untreated cells. When TP and TPR were mixed ex vivo, TPR mitigated TP-induced permeability, with significant increase in AUC compared with TP alone. Metabolomics of TPR and TP demonstrated disrupted redox reactions and anti-inflammatory mechanisms.

CONCLUSION

Trauma platelet releasates provide endothelial barrier protection against TP-induced endothelial permeability. Our findings highlight a potential beneficial action of activated platelets on the endothelium in injured patients through disrupted redox reactions and increased antioxidants. Our findings support that soluble signaling from platelet degranulation may mitigate the endotheliopathy of trauma. The clinical implications of this are that activated platelets may prove a promising therapeutic target in the complex integration of thrombosis, endotheliopathy, and inflammation in trauma.

Multiomics Signatures of Coagulopathy in a Polytrauma Swine Model Contrasted with Severe Multisystem Injured Patients

Trauma-induced coagulopathy (TIC) is a leading contributor to preventable mortality in severely injured patients. Understanding the molecular drivers of TIC is an essential step in identifying novel therapeutics to reduce morbidity and mortality. This study investigated multiomics and viscoelastic responses to polytrauma using our novel swine model and compared these findings with severely injured patients. Molecular signatures of TIC were significantly associated with perturbed coagulation and inflammation systems as well as extensive hemolysis. These results were consistent with patterns observed in trauma patients who had multisystem injuries. Here, intervention using resuscitative endovascular balloon occlusion of the aorta following polytrauma in our swine model revealed distinct multiomics alterations as a function of placement location. Aortic balloon placement in zone-1 worsened ischemic damage and mitochondrial dysfunction, patterns that continued throughout the monitored time course. While placement in zone-III showed a beneficial effect on TIC, it showed an improvement in effective coagulation. Taken together, this study highlights the translational relevance of our polytrauma swine model for investigating therapeutic interventions to correct TIC in patients.