Host responses to concurrent combined injuries in non-human primates

Development, refinement, and characterization of a nonhuman primate critical care environment

BACKGROUND

Systemic inflammatory response remains a poorly understood cause of morbidity and mortality after traumatic injury. Recent nonhuman primate (NHP) trauma models have been used to characterize the systemic response to trauma, but none have incorporated a critical care phase without the use of general anesthesia. We describe the development of a prolonged critical care environment with sedation and ventilation support, and also report corresponding NHP biologic and inflammatory markers.

METHODS

Eight adult male rhesus macaques underwent ventilation with sedation for 48-96 hours in a critical care setting. Three of these NHPs underwent "sham" procedures as part of trauma control model development. Blood counts, chemistries, coagulation studies, and cytokines/chemokines were collected throughout the study, and histopathologic analysis was conducted at necropsy.

RESULTS

Eight NHPs were intentionally survived and extubated. Three NHPs were euthanized at 72-96 hours without extubation. Transaminitis occurred over the duration of ventilation, but renal function, acid-base status, and hematologic profile remained stable. Chemokine and cytokine analysis were notable for baseline fold-change for Il-6 and Il-1ra (9.7 and 42.7, respectively) that subsequently downtrended throughout the experiment unless clinical respiratory compromise was observed.

CONCLUSIONS

A NHP critical care environment with ventilation support is feasible but requires robust resources. The inflammatory profile of NHPs is not profoundly altered by sedation and mechanical ventilation. NHPs are susceptible to the pulmonary effects of short-term ventilation and demonstrate a similar bioprofile response to ventilator-induced pulmonary pathology. This work has implications for further development of a prolonged care NHP model.

Characterization of the cortisol response to traumatic hemorrhage and intra-abdominal contamination models in Cynomologus Macaques

INTRODUCTION

Trauma, hemorrhage, and peritonitis have widely varying impacts on endocrine response in the injured patient. We sought to examine cortisol response in established non-human primate models of traumatic hemorrhage and intra-abdominal contamination.

METHODS

Cynomologus Macaques were separated into two experimental groups, the polytrauma and hemorrhage model, involving a laparoscopic liver resection with uncontrolled hemorrhage, cecal perforation, and soft tissue excision; and the traumatic hemorrhage model, involving only liver resection and uncontrolled hemorrhage. Cortisol levels were measured pre-operatively, at the time of injury, and at regular intervals until post-operative day 1.

RESULTS

Cortisol levels increased 600% from the pre-operative value in the polytrauma and hemorrhage model, with minimal changes (20%) in the hemorrhage only model.

CONCLUSION

Cortisol levels increase dramatically in response to polytrauma and intra-abdominal contamination as compared to hemorrhage only. The lack of response in the hemorrhage only group may be due to relative adrenal insufficiency caused by the shock state or lack of enticing stimuli from fecal peritonitis.

Concomitant chest trauma and traumatic brain injury, biomarkers correlate with worse outcomes

BACKGROUND

Clinical data are lacking on the influence of chest trauma on the secondary injury process after traumatic brain injury (TBI), with some data suggesting that multiple trauma may worsens brain injury. Blunt chest trauma and TBI represent the two major single injury entities with the highest risk of complications and are potential biomarker targets.

METHODS

Trauma patients with severe TBI were enrolled. Serum biomarker levels were obtained every 6 hours for 72 hours. Baseline, 6 hours and 24 hours CT head scans were evaluated. Neurologic worsening was defined as increased contusions, ischemia, compression of basal cisterns, and/or midline shift. The TBI patients with chest injury (Abbreviated Injury Scale chest score ≥1) and those without chest injury were compared. Wilcoxon rank sum test, univariate logistic regression and receiver operating characteristic were reported.

RESULTS

Fifty-seven patients. Mean age of 40.5 years. Median motor Glasgow Coma Scale score at admission and 24 hours was 3 (interquartile range, 1-5) and 5 (interquartile range, 3-5). Of the patients enrolled, 12.2% patients underwent craniotomy within 6 hours from the time of admission and 22.8% within 12 hours. Patients with chest trauma, 24.5% had a chest Abbreviated Injury Scale score of 3 or greater, and 73.6% sustained blunt chest trauma. Stratifying TBI patients with and without chest injury revealed higher mean levels of IL-4, IL-5, IL-8, and IL-10 and lower mean IFN-γ and IL-7 levels in patient with chest injury. IL-7 levels adjusted for chest injury predicted neurological worsening with area under the receiver operating characteristic of 0.59 (p value = 0.011). The TBI and chest trauma patients' IL-4 and neuron-specific enolase levels were predictive of mortality (area under the receiver operating characteristic of 0.67 and 0.63, p = 0.0001, 0.003), respectively.

CONCLUSION

Utilizing biomarkers for early identification of patients with TBI and chest trauma has the capability of modifying adverse factors affecting morbidity and mortality in this subset of TBI patients.

LEVEL OF EVIDENCE

Level III.

Impact of epidural analgesia on the systemic biomarker response after hepatic resection

Background

Perioperative inflammation is associated with poor oncologic outcomes. Regional analgesia has been shown mitigate some of these inflammatory changes and be associated with better oncologic outcomes in patients with hepatic malignancies. The mechanism for this effect, however, remains unclear. The authors sought to compare systemic biomarker concentrations in a comprehensive and oncologically relevant panel in the perioperative setting between patients undergoing thoracic epidural analgesia (TEA) and intra-venous patient- controlled analgesia (IV-PCA) for resection of hepatic metastatic disease.

Results

Clinicopathologic variables and baseline biomarkers were similar between TEA (n = 46) and IV-PCA (n = 16) groups. Of the biomarkers which were significantly changed from baseline, there was a lower fold change from baseline in the TEA patients compared to IV-PCA including IL-6 (13.5vs19.1), MCP-1 (1.9vs3.0), IL-8 (2.4vs3.0), and Pentraxin-3 (10.8vs15.6). Overall decreased systemic concentrations of TGFb signaling were noted in TEA patients on POD1 TGFb3 (243.2 vs. 86.0, p = 0.005), POD3 TGFb1 (6558.0 vs. 2063.3, p = 0.004), POD3 TGFb2 (468.3 vs. 368.9, p = 0.036), POD3 TGFb3 (132.2 vs. 77.8, p = 0.028), and POD5 TGFb3 (306.5 vs. 92.2, p = 0.032). POD1 IL-12p70 concentrations were significantly higher in TEA patients (8.3 vs. 1.6, p = 0.024).

Conclusion

Epidural analgesia damped the postoperative inflammatory response and systemic immunosuppressive signaling, as well as promoted Th1 systemic signaling early in the post-operative period after hepatic resection for metastatic disease. These differences elaborate on known mechanisms for improved oncologic outcomes with regional anesthesia, and may be considered for biomarker monitoring of effective regional anesthesia in oncologic surgery.

Materials and Methods

Patient data, including clinicopathologic variables were collected for this study from the database of a randomized controlled trial comparing perioperative outcomes in patients undergoing hepatic resection with TEA vs. IV-PCA. Patients undergoing resection for metastatic disease were selected for this study. Plasma concentrations (pg/mL) of well-studied biomarkers (IL-1b/2/4/5/6/7/8/10/12p70/13/17, MCP-1 IFNγ, TNFα, MIP-1b, GM-CSF, G-CSF, VEGF, Resistin, TGFb1, TGFb2, and TGFb3), as well as novel perioperative markers (CXCL12, CXCL10, Omentin-1, sLeptin R, Vaspin, Pentraxin-3, Galactin-3, FGF-23, PON-1, FGF-21) were measured preoperatively, and on postoperative day (POD)1, POD3, and POD5 using multiplex bead assays. Clinicopathologic variables and perioperative variations in these biomarkers were compared between TEA vs IV-PCA groups.

Enrichment-triggered prodrug activation demonstrated through mitochondria-targeted delivery of doxorubicin and carbon monoxide

Controlled activation is a critical component in prodrug development. Here we report a concentration-sensitive platform approach for bioorthogonal prodrug activation by taking advantage of reaction kinetics. Using two 'click and release' systems, we demonstrate enrichment and prodrug activation specifically in mitochondria to demonstrate the principle of the approach. In both cases, the payload (doxorubicin or carbon monoxide) was released inside the mitochondrial matrix following the enrichment-initiated click reaction. Furthermore, mitochondria-targeted delivery yielded substantial augmentation of functional biological and therapeutic effects in vitro and in vivo when compared to controls, which did not result in enrichment. This method is thus a platform for targeted drug delivery that is amenable to conjugation with a variety of molecules and is not limited to cell-surface delivery. Taken together, these two 'click and release' pairs clearly demonstrate the concept of enrichment-triggered drug release and the critical feasibility of treating clinically relevant diseases such as acute liver injury and cancer.

The impact of septic stimuli on the systemic inflammatory response and physiologic insult in a preclinical non-human primate model of polytraumatic injury

BACKGROUND

Established animal trauma models are limited in recapitulating the pathophysiology of human traumatic injury. Herein, we characterize the physiologic insult and inflammatory response in two clinically relevant non-human primate (NHP) trauma models.

METHODS

Mauritian Cynomolgus Macaques underwent either a laparoscopic closed abdomen liver injury (laparoscopic 60% left-lobe hepatectomy) in an established uncontrolled severe hemorrhage model (THM), or a polytrauma hemorrhage model (PHM) involving combined liver and bowel injury, uncontrolled severe hemorrhage as well as an open full-thickness cutaneous flank wound. Fixed volume resuscitation strategies were employed in the THM and goal directed resuscitation was used in the PHM. Complete peripheral blood and critical clinical chemistry parameters, serum biomarkers of systemic inflammation, tissue perfusion parameters, as well as survival, were compared between the models throughout the 2-week study period.

RESULTS

NHPs in both the THM (n = 7) and the PHM (n = 21) demonstrated tissue hypoperfusion (peak lactate 6.3 ± 0.71 mmol/L) with end organ injury (peak creatinine 3.08 ± 0.69 mg/dL) from a similar liver injury (60% left hemi-hepatectomy), though the PHM NHPs had a significantly higher blood loss (68.1% ± 12.7% vs. 34.3% ± 2.3%, p = 0.02), lower platelet counts (59 ± 25 vs. 205 ± 46 K/uL, p = 0.03) and a trend towards higher mortality (90.5% vs. 33.3%, p = 0.09). The inflammatory response was robust in both models with peak cytokine (IL-6 > 6000-fold above baseline) and peak leukocyte values (WBC 27 K/uL) typically occurring around t = 240 min from the time of hepatic injury. A more robust systemic inflammatory response was appreciated in the PHM resulting in marked elevations in peak serum IL-6 (7887 ± 2521 pg/mL vs.1076 ± 4833 pg/mL, p = 0.02), IL-1ra (34,499 ± 5987 pg/mL vs. 2511 ± 1228 pg/mL, p < 0.00), and IL-10 (13,411 pg/mL ± 5598 pg/mL vs. 617 pg/mL ± 252 pg/mL, p = 0.03).

CONCLUSION

This comparative analysis provides a unique longitudinal perspective on the post-injury inflammatory response in two clinically relevant models, and demonstrates that the addition of septic stimuli to solid organ injury increases both the hemorrhagic insult and inflammatory response.