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Walker PF, Foster AD, Rothberg PA, Davis TA, Bradley MJ. Tranexamic acid decreases rodent hemorrhagic shock-induced inflammation with mixed end-organ effects. PLoS One 2018; 13:e0208249. [PMID: 30496326 PMCID: PMC6264800 DOI: 10.1371/journal.pone.0208249] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 11/08/2018] [Indexed: 11/18/2022] Open
Abstract
Beyond its anti-fibrinolytic mechanism, tranexamic acid has been suggested to have anti-inflammatory properties which may contribute to the survival benefit it provides to trauma patients. The objective of this study was to assess possible immunomodulatory effects of tranexamic acid as well as potential amelioration of end-organ injury in a rodent hemorrhagic shock model. Controlled hemorrhagic shock was induced in adult Sprague Dawley rats to a mean arterial pressure of 30 mmHg. Groups of 10 rats were administered intravenous tranexamic acid (300mg/kg) or vehicle control (normal saline) intravenously 15 minutes after the induction of shock. After 60 minutes of hemorrhagic shock, resuscitation was started. Animals were euthanized at six, 24, or 72 hours from the start of shock. Serum laboratory values to include inflammatory biomarkers were measured, and end organ histology was evaluated. Tranexamic acid treatment was associated with a significant decrease in serum IL-1β at six and 24 hours and IL-10 at 24 hours from start of shock compared to vehicle control. Histologic analysis demonstrated mild decreases in both perivascular pulmonary edema and follicular mesenteric lymph node hyperplasia in the tranexamic acid treatment group but also increased myocardial lymphocytic infiltration with necrosis and degeneration. Tranexamic acid was also associated with a small but significant increase in peripheral neutrophil count as well as a significant decrease in neutrophil aggregation in pulmonary tissue at six hours post-injury. These data thus demonstrate a mixed effect of tranexamic acid. While there was an improvement in pulmonary edema and a suppressive effect on several key inflammatory mediators, there was also increased myocardial degeneration and necrosis, which is possibly related to the pro-thrombotic effect of tranexamic acid.
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Weller M, Butowski N, Tran DD, Recht LD, Lim M, Hirte H, Ashby L, Mechtler L, Goldlust SA, Iwamoto F, Drappatz J, O'Rourke DM, Wong M, Hamilton MG, Finocchiaro G, Perry J, Wick W, Green J, He Y, Turner CD, Yellin MJ, Keler T, Davis TA, Stupp R, Sampson JH. Go, no-go decision making for phase 3 clinical trials: ACT IV revisited - Authors' reply. Lancet Oncol 2018; 18:e709-e710. [PMID: 29208433 DOI: 10.1016/s1470-2045(17)30856-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 11/03/2017] [Accepted: 11/03/2017] [Indexed: 10/18/2022]
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Vicente DA, Bradley MJ, Bograd B, Leonhardt C, Elster EA, Davis TA. The impact of septic stimuli on the systemic inflammatory response and physiologic insult in a preclinical non-human primate model of polytraumatic injury. JOURNAL OF INFLAMMATION-LONDON 2018; 15:11. [PMID: 29849508 PMCID: PMC5968671 DOI: 10.1186/s12950-018-0187-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/13/2018] [Indexed: 11/10/2022]
Abstract
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.
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Martin EC, Qureshi AT, Llamas CB, Boos EC, King AG, Krause PC, Lee OC, Dasa V, Freitas MA, Forsberg JA, Elster EA, Davis TA, Gimble JM. Trauma induced heterotopic ossification patient serum alters mitogen activated protein kinase signaling in adipose stem cells. J Cell Physiol 2018; 233:7035-7044. [PMID: 29377109 DOI: 10.1002/jcp.26504] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/24/2018] [Indexed: 12/15/2022]
Abstract
Post-traumatic heterotopic ossification (HO) is the formation of ectopic bone in non-osseous structures following injury. The precise mechanism for bone development following trauma is unknown; however, early onset of HO may involve the production of pro-osteogenic serum factors. Here we evaluated serum from a cohort of civilian and military patients post trauma to determine early induction gene signatures in orthopaedic trauma induced HO. To test this, human adipose derived stromal/stem cells (hASCs) were stimulated with human serum from patients who developed HO following trauma and evaluated for a gene panel with qPCR. Pathway gene analysis ontology revealed that hASCs stimulated with serum from patients who developed HO had altered gene expression in the activator protein 1 (AP1) and AP1 transcriptional targets pathways. Notably, there was a significant repression in FOS gene expression in hASCs treated with serum from individuals with HO. Furthermore, the mitogen-activated protein kinase (MAPK) signaling pathway was activated in hASCs following serum exposure from individuals with HO. Serum from both military and civilian patients with trauma induced HO had elevated downstream genes associated with the MAPK pathways. Stimulation of hASCs with known regulators of osteogenesis (BMP2, IL6, Forskolin, and WNT3A) failed to recapitulate the gene signature observed in hASCs following serum stimulation, suggesting non-canonical mechanisms for gene regulation in trauma induced HO. These findings provide new insight for the development of HO and support ongoing work linking the systemic response to injury with wound specific outcomes.
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Wheatley BM, Cilwa KE, Dey D, Qureshi AT, Seavey JG, Tomasino AM, Sanders EM, Bova W, Boehm CA, Iwamoto M, Potter BK, Forsberg JA, Muschler GF, Davis TA. Palovarotene inhibits connective tissue progenitor cell proliferation in a rat model of combat-related heterotopic ossification. J Orthop Res 2018; 36:1135-1144. [PMID: 28960501 DOI: 10.1002/jor.23747] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/20/2017] [Indexed: 02/04/2023]
Abstract
Heterotopic ossification (HO) develops in the extremities of wounded service members and is common in the setting of high-energy penetrating injuries and blast-related amputations. No safe and effective prophylaxis modality has been identified for this patient population. Palovarotene has been shown to reduce bone formation in traumatic and genetic models of HO. The purpose of this study was to determine the effects of Palovarotene on inflammation, progenitor cell proliferation, and gene expression following a blast-related amputation in a rodent model (n = 72 animals), as well as the ability of Raman spectroscopy to detect early HO before radiographic changes are present. Treatment with Palovarotene was found to dampen the systemic inflammatory response including the cytokines IL-6 (p = 0.01), TNF-α (p = 0.001), and IFN-γ (p = 0.03) as well as the local inflammatory response via a 76% reduction in the cellular infiltration at post-operative day (POD)-7 (p = 0.03). Palovarotene decreased osteogenic connective tissue progenitor (CTP-O) colonies by as much as 98% both in vitro (p = 0.04) and in vivo (p = 0.01). Palovarotene treated animals exhibited significantly decreased expression of osteo- and chondrogenic genes by POD-7, including BMP4 (p = 0.02). Finally, Raman spectroscopy was able to detect differences between the two groups by POD-1 (p < 0.001). These results indicate that Palovarotene inhibits traumatic HO formation through multiple inter-related mechanisms including anti-inflammatory, anti-proliferative, and gene expression modulation. Further, that Raman spectroscopy is able to detect markers of early HO formation before it becomes radiographically evident, which could facilitate earlier diagnosis and treatment. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1135-1144, 2018.
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Cholok D, Chung MT, Ranganathan K, Ucer S, Day D, Davis TA, Mishina Y, Levi B. Heterotopic ossification and the elucidation of pathologic differentiation. Bone 2018; 109:12-21. [PMID: 28987285 PMCID: PMC6585944 DOI: 10.1016/j.bone.2017.09.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/27/2017] [Accepted: 09/27/2017] [Indexed: 01/23/2023]
Abstract
Tissue regeneration following acute or persistent inflammation can manifest a spectrum of phenotypes ranging from the adaptive to the pathologic. Heterotopic Ossification (HO), the endochondral formation of bone within soft-tissue structures following severe injury serves as a prominent example of pathologic differentiation; and remains a persistent clinical issue incurring significant patient morbidity and expense to adequately diagnose and treat. The pathogenesis of HO provides an intriguing opportunity to better characterize the cellular and cell-signaling contributors to aberrant differentiation. Indeed, recent work has continued to resolve the unique cellular lineages, and causative pathways responsible for ectopic bone development yielding promising avenues for the development of novel therapeutic strategies shown to be successful in analogous animal models of HO development. This review details advances in the understanding of HO in the context of inciting inflammation, and explains how these advances inform the current standards of diagnosis and treatment.
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Aleynick M, Peng P, Hammerich L, Upadhyay R, Marshall N, Agudo J, Yellin MJ, Keler T, Davis TA, Brown B, Brody J. Natural pattern-recognition-receptor agonists as adjuvants for in situ vaccination lymphoma immunotherapy. J Clin Oncol 2018. [DOI: 10.1200/jco.2018.36.5_suppl.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
123 Background: In patients with low-grade lymphoma, in situ vaccination has yielded both partial and complete remissions in clinical trials. Though clinical responses have been observed with multiple pattern recognition receptor agonists (PRRa), the optimal immune stimulant is unknown. We hypothesize that natural PRRa, such as the attenuated pathogens or subunits found in common prophylactic vaccines, could target multiple PRR in a physiologically relevant context and lead to a more robust activation of dendritic cells (DCs) versus synthetic PRRa. Methods: 20 vaccines, including BCG, Typhim Vi, MMR-II, etc. were screened in vitro, where DC phenotype and function were evaluated by flow cytometry. Flt3L-mobilized DC ability to phagocytose, process, present, and cross-present soluble protein or tumor derived antigen, were assessed using CRISPR gene-edited, β2m(-/-) GFP-lymphoma cells and a novel GFP-specific (‘JEDI’) CD8 T cell system. Vaccine mechanism of immune activation was elucidated using a library of PRR-null macrophage cell lines. Potent vaccines were also evaluated in vivo in a Flt3L-primed in situ vaccination using the A20 murine lymphoma model. Results: Several vaccines induced robust DC activation and several showed significant increases in subsequent T cell activation, proliferation, and tumor killing, suggesting increased antigen processing and cross-presentation by DCs. Some vaccines, either as single agents or in combination, were significantly more effective than synthetic PRRa in activating DCs and inducing a T cell response. In vivo, vaccine combination therapies induced tumor regression in a majority of animals, suggesting synergistic immune activation. Conclusions: This data suggests prophylactic vaccines are effective clinical-grade DC activators and can be repurposed for use in the in situ vaccination maneuver, with immediate translation into the clinic. Additionally, by extensive in vitro evaluation in parallel with in vivo studies, this work aims to identify a predictive in vitro molecular immune signature that correlates closely with adjuvant efficacy in vivo.
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Hammerich L, Dhainaut M, Davis TA, Keler T, Salazar AM, Brown BD, Brody J. Improving efficacy of PD-1 blockade in unresponsive lymphoma tumors with in situ vaccination through induction of a highly efficient cross-presenting dendritic cell subset. J Clin Oncol 2018. [DOI: 10.1200/jco.2018.36.5_suppl.76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
76 Background: Low-grade non-Hodgkin’s B-cell lymphomas are generally incurable; preliminary results with anti-PD-1 therapy have yielded low response rates. Tumoral DC infiltration correlates with efficacy of checkpoint blockade and tumor-targeted vaccines represent promising, novel treatment strategies to induce anti-tumor T cells. Methods: A20 lymphoma-bearing mice were treated with a PD-1 blocking antibody with an in situ vaccine (ISV) consisting of intratumoral injections of FMS-like tyrosine kinase-3 ligand (Flt3L), local irradiation (XRT) of the tumor and intratumoral injections of the TLR3 agonist poly-ICLC (pIC). Results: Untreated lymphoma tumors contained very low numbers of DC and treatment with anti-PD1 alone did not induce tumor regression or increase survival. Flt3L treatment resulted in a dramatic increase of IRF8+TLR3+ DC at the tumor site, the draining lymph node and the spleen. XRT of A20 cells induced activation of Flt3L-treated splenic DC in vitro and local XRT of the tumor in vivo induced expression of CD103 on infiltrating TLR3+ DC. Local XRT also enhanced uptake of dying tumor cells by DC. Interestingly, tumor antigens were taken up mainly by CD103+ DC and not CD103- subtypes. CD103+ expression distinguishes a subset of migratory cross-presenting DC. Accordingly, CD103+ DC isolated from the tumor induced proliferation of tumor-specific CD8+ T cells more efficiently than CD103- subsets. The combination of Flt3L with XRT and pIC induced tumor-reactive, IFNg-producing T cells, but delayed tumor growth and improved survival only in 40% of mice. ISV also increased expression of PD-L1 on tumor cells and tumor infiltrating DC. Consistently, combination of ISV with PD-1 blockade led to complete tumor regression and increased long-term survival in the majority of mice. PD-1 blockade also increased the number of tumor-reactive T cells and depletion of CD8+ T cells abrogated the anti-tumor effect. Conclusions: In situ vaccination can improve efficacy of anti-PD-1 in checkpoint-unresponsive lymphoma tumors through induction of a cross-presenting DC subset leading to long-term regression of established lymphoma tumors.
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Foster AD, Clark N, Davis TA. Induction of Skin Allograft Transplantation Tolerance in Mice Using Human Adipose Derived Stromal Cells. Methods Mol Biol 2018; 1773:73-91. [PMID: 29687382 DOI: 10.1007/978-1-4939-7799-4_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Murine models of allograft transplantation are valuable for understanding the immunological mechanisms of allograft acceptance and rejection, the evaluation of immunosuppressive drugs and strategies, and the restoration of functional defects. Herein, we describe methods to create a skin murine allograft surgical model and how to administer adipose-derived stromal cells (ASC) with limited numbers of donor bone marrow to create stable multilineage donor cell chimerism and indefinite immunological tolerance.
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Bradley MJ, Vicente DA, Bograd BA, Sanders EM, Leonhardt CL, Elster EA, Davis TA. Host responses to concurrent combined injuries in non-human primates. JOURNAL OF INFLAMMATION-LONDON 2017; 14:23. [PMID: 29118676 PMCID: PMC5667447 DOI: 10.1186/s12950-017-0170-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 10/23/2017] [Indexed: 11/10/2022]
Abstract
Background Multi-organ failure (MOF) following trauma remains a significant cause of morbidity and mortality related to a poorly understood abnormal inflammatory response. We characterized the inflammatory response in a non-human primate soft tissue injury and closed abdomen hemorrhage and sepsis model developed to assess realistic injury patterns and induce MOF. Methods Adult male Mauritan Cynomolgus Macaques underwent laparoscopy to create a cecal perforation and non-anatomic liver resection along with a full-thickness flank soft tissue injury. Treatment consisted of a pre-hospital phase followed by a hospital phase after 120 minutes. Blood counts, chemistries, and cytokines/chemokines were measured throughout the study. Lung tissue inflammation/apoptosis was confirmed by mRNA quantitative real-time PCR (qPCR), H&E, myeloperoxidase (MPO) and TUNEL staining was performed comparing age-matched uninjured controls to experimental animals. Results Twenty-one animals underwent the protocol. Mean percent hepatectomy was 64.4 ± 5.6; percent blood loss was 69.0 ± 12.1. Clinical evidence of end-organ damage was reflected by a significant elevation in creatinine (1.1 ± 0.03 vs. 1.9 ± 0.4, p=0.026). Significant increases in systemic levels of IL-10, IL-1ra, IL-6, G-CSF, and MCP-1 occurred (11-2986-fold) by 240 minutes. Excessive pulmonary inflammation was evidenced by alveolar edema, congestion, and wall thickening (H&E staining). Concordantly, amplified accumulation of MPO leukocytes and significant pulmonary inflammation and pneumocyte apoptosis (TUNEL) was confirmed using qRT-PCR. Conclusion We created a clinically relevant large animal multi-trauma model using laparoscopy that resulted in a significant systemic inflammatory response and MOF. With this model, we anticipate studying systemic inflammation and testing innovative therapeutic options.
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Seavey JG, Wheatley BM, Pavey GJ, Tomasino AM, Hanson MA, Sanders EM, Dey D, Moss KL, Potter BK, Forsberg JA, Qureshi AT, Davis TA. Early local delivery of vancomycin suppresses ectopic bone formation in a rat model of trauma-induced heterotopic ossification. J Orthop Res 2017; 35:2397-2406. [PMID: 28390182 DOI: 10.1002/jor.23544] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 02/09/2017] [Indexed: 02/04/2023]
Abstract
Heterotopic ossification (HO) is a debilitating sequela of high-energy injuries. It frequently requires surgical excision once symptomatic and there is no practical prophylaxis for combat-injured patients. In this study, we examined the effect of local vancomycin powder on HO formation in a small animal model of blast-related, post-traumatic HO. Male Sprague-Dawley rats were subjected to a polytraumatic extremity injury and amputation with or without methicillin-resistant Staphylococcus aureus infection. Animals were randomized to receive a single local application of vancomycin (20 mg/kg) at the time of injury (POD-0, n = 34) or on postoperative day-3 (POD-3, n = 11). Quantitative volumetric measurement of ectopic bone was calculated at 12-weeks post-injury by micro-CT. Bone marrow and muscle tissues were also collected to determine the bacterial burden. Blood for serum cytokine analysis was collected at baseline and post-injury. Vancomycin treatment on POD-0 suppressed HO formation by 86% and prevented bone marrow and soft tissue infections. We concurrently observed a marked reduction histologically in nonviable tissue, chronic inflammatory cell infiltrates, bone infection, fibrous tissue, and areas of bone necrosis within this same cohort. Delayed treatment was significantly less efficacious. Neither treatment had a marked effect on the production of pro-inflammatory cytokines. Our study demonstrates that local vancomycin treatment at the time of injury significantly reduces HO formation in both the presence and absence of infection, with decreased efficacy if not given early. These findings further support the concept that the therapeutic window for prophylaxis is narrow, highlighting the need to develop early treatment strategies for clinical management. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2397-2406, 2017.
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Qureshi AT, Dey D, Sanders EM, Seavey JG, Tomasino AM, Moss K, Wheatley B, Cholok D, Loder S, Li J, Levi B, Davis TA. Inhibition of Mammalian Target of Rapamycin Signaling with Rapamycin Prevents Trauma-Induced Heterotopic Ossification. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2536-2545. [PMID: 29029772 DOI: 10.1016/j.ajpath.2017.07.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/18/2017] [Accepted: 07/26/2017] [Indexed: 12/27/2022]
Abstract
A pressing clinical need exists for 63% to 65% of combat-wounded service members and 11% to 20% of civilians who develop heterotopic ossification (HO) after blast-related extremity injury and traumatic injuries, respectively. The mammalian target of rapamycin pathway is a central cellular sensor of injury. We evaluated the prophylactic effects of rapamycin, a selective inhibitor of mammalian target of rapamycin signaling, on HO formation in a rat model of blast-related, polytraumatic extremity injury. Rapamycin was administered intraperitoneally daily for 14 days at 0.5 mg/kg or 2.5 mg/kg. Ectopic bone formation was monitored by micro-computed tomography and confirmed by histologic examination. Connective tissue progenitor cells, platelet-derived growth factor receptor-α-positive cells, and α-smooth muscle actin-positive blood vessels were assayed at postoperative day 7 by colony formation and immunofluorescence. Early gene expression changes were determined by low-density microarray. There was significant attenuation of 1) total new bone and soft tissue ectopic bone with 0.5 mg/kg (38.5% and 14.7%) and 2.5 mg/kg rapamycin (90.3% and 82.9%), respectively, 2) connective tissue progenitor cells, 3) platelet-derived growth factor receptor-α-positive cells, 4) α-smooth muscle actin-positive blood vessels, and 5) of key extracellular matrix remodeling (CD44, Col1a1, integrins), osteogenesis (Sp7, Runx2, Bmp2), inflammation (Cxcl5, 10, IL6, Ccl2), and angiogenesis (Angpt2) genes. No wound healing complications were noted. Our data demonstrate the efficacy of rapamycin in inhibiting blast trauma-induced HO by a multipronged mechanism.
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Cappelle M, Walker WS, Davis TA. Improving Desalination Recovery Using Zero Discharge Desalination (ZDD): A Process Model for Evaluating Technical Feasibility. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.7b02472] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Salisbury EA, Dickerson AR, Davis TA, Forsberg JA, Davis AR, Olmsted-Davis EA. Characterization of Brown Adipose-Like Tissue in Trauma-Induced Heterotopic Ossification in Humans. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2071-2079. [PMID: 28686851 DOI: 10.1016/j.ajpath.2017.05.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/03/2017] [Accepted: 05/15/2017] [Indexed: 12/27/2022]
Abstract
Heterotopic ossification (HO), the abnormal formation of bone within soft tissues, is a major complication after severe trauma or amputation. Transient brown adipocytes have been shown to be a critical regulator of this process in a mouse model of HO. In this study, we evaluated the presence of brown fat within human HO lesions. Most of the excised tissue samples displayed histological characteristics of bone, fibroproliferative cells, blood vessels, and adipose tissue. Immunohistochemical analysis revealed extensive expression of uncoupling protein 1 (UCP1), a definitive marker of brown adipocytes, within HO-containing tissues but not normal tissues. As seen in the brown adipocytes observed during HO in the mouse, these UCP1+ cells also expressed the peroxisome proliferator-activated receptor γ coactivator 1α. However, further characterization showed these cells, like their mouse counterparts, did not express PR domain containing protein 16, a key factor present in brown adipocytes found in depots. Nor did they express factors present in beige adipocytes. These results identify a population of UCP1+ cells within human tissue undergoing HO that do not entirely resemble either classic brown or beige adipocytes, but rather a specialized form of brown adipocyte-like cells, which have a unique function. These cells may offer a new target to prevent this unwanted bone.
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Burris HA, Infante JR, Ansell SM, Nemunaitis JJ, Weiss GR, Villalobos VM, Sikic BI, Taylor MH, Northfelt DW, Carson WE, Hawthorne TR, Davis TA, Yellin MJ, Keler T, Bullock T. Safety and Activity of Varlilumab, a Novel and First-in-Class Agonist Anti-CD27 Antibody, in Patients With Advanced Solid Tumors. J Clin Oncol 2017; 35:2028-2036. [DOI: 10.1200/jco.2016.70.1508] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Purpose CD27, a costimulatory molecule on T cells, induces intracellular signals that mediate cellular activation, proliferation, effector function, and cell survival upon binding to its ligand, CD70. Varlilumab is a novel, first-in-class, agonist CD27 antibody that stimulates the CD27 pathway, which results in T-cell activation and antitumor activity in tumor models. This first-in-human, dose-escalation and expansion study evaluated the safety, pharmacology, and activity of varlilumab in patients with advanced solid tumors. Methods In a 3 + 3 dose-escalation design (n = 25), patients received a single dose of varlilumab (0.1, 0.3, 1.0, 3.0, or 10 mg/kg intravenously) with a 28-day observation, followed by up to five multidose cycles (one dose per week for 4 weeks), depending on tumor response. Expansion cohorts were initiated at 3.0 mg/kg in patients with melanoma (n = 16) and renal cell carcinoma (RCC; n = 15). Primary objectives were to assess the safety and the maximum tolerated and optimal biologic doses of varlilumab. Secondary objectives were to evaluate the pharmacokinetics, pharmacodynamics, and clinical antitumor activity of varlilumab. Results Exposure to varlilumab was linear and dose proportional across dose groups. Only one patient experienced a dose-limiting toxicity—grade 3 transient asymptomatic hyponatremia at the 1.0-mg/kg dose level. Treatment-related adverse events were generally grade 1 or 2 in severity. Evidence of biologic activity consistent with CD27 stimulation—chemokine induction, T-cell stimulation, regulatory T cell depletion—was observed at all dose levels. A patient with metastatic RCC experienced a partial response (78% shrinkage, progression-free survival > 2.3 years). Eight patients experienced stable disease > 3 months, including a patient with metastatic RCC with progression-free survival of > 3.9 years. Conclusion Dose escalation of varlilumab to 10 mg/kg was well tolerated without identification of a maximum tolerated dose. Varlilumab was biologically and clinically active.
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Olmsted-Davis EA, Salisbury EA, Hoang D, Davis EL, Lazard Z, Sonnet C, Davis TA, Forsberg JA, Davis AR. Progenitors in Peripheral Nerves Launch Heterotopic Ossification. Stem Cells Transl Med 2017; 6:1109-1119. [PMID: 28198109 PMCID: PMC5442844 DOI: 10.1002/sctm.16-0347] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/31/2016] [Indexed: 12/23/2022] Open
Abstract
Studies presented here, using a murine model of bone morphogenetic protein type 2 (BMP2)-induced heterotopic ossification (HO) show that the protein initiates HO by signaling through progenitors in the endoneurium of peripheral nerves. In the mouse, these cells were identified in the endoneurium one day after BMP2 induction using antibody against phosphoSMAD (PS) 1, 5, and 8. Studies conducted in a tracking mouse that contains a tamoxifen-regulated Wnt1-Cre recombinase crossed with a td Tomato red (TR) reporter (Wnt1CreErt :Ai9Tm) confirmed their neural origin. In this model both BMP2 induction and tamoxifen are absolutely required to induce TR. SP7+ (osterix+ )TR+ cells were found in the endoneurium on day 1 and associated with bone on day 7. Quantification of TR+ and TR- cells isolated by fluorescence-activated cell sorting showed that all SP7+ cells were found in the TR+ population, whereas only about 80% of the TR+ cells expressed SP7. Pre-chondrocytes (Sox 9+ ) and transient brown fat (tBAT, UCP1+ ) also coexpressed TR, suggesting that the progenitor in nerves is multi-potential. The endoneurium of human nerves near the site of HO contained many PS+ cells, and SP7+ cells were found in nerves and on bone in tissue from patients with HO. Control tissues and nerves did not contain these PS+ and SP7+ cells. Some osteoblasts on bone from patients with HO were positive for PS, suggesting the continued presence of BMP during bone formation. The data suggests that the progenitors for HO are derived from the endoneurium in both the mouse model of HO and in humans with HO. Stem Cells Translational Medicine 2017;6:1109-1119.
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Agarwal S, Loder SJ, Cholok D, Peterson J, Li J, Breuler C, Cameron Brownley R, Hsin Sung H, Chung MT, Kamiya N, Li S, Zhao B, Kaartinen V, Davis TA, Qureshi AT, Schipani E, Mishina Y, Levi B. Scleraxis-Lineage Cells Contribute to Ectopic Bone Formation in Muscle and Tendon. Stem Cells 2016; 35:705-710. [PMID: 27862618 DOI: 10.1002/stem.2515] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 09/16/2016] [Indexed: 11/11/2022]
Abstract
The pathologic development of heterotopic ossification (HO) is well described in patients with extensive trauma or with hyperactivating mutations of the bone morphogenetic protein (BMP) receptor ACVR1. However, identification of progenitor cells contributing to this process remains elusive. Here we show that connective tissue cells contribute to a substantial amount of HO anlagen caused by trauma using postnatal, tamoxifen-inducible, scleraxis-lineage restricted reporter mice (Scx-creERT2/tdTomatofl/fl ). When the scleraxis-lineage is restricted specifically to adults prior to injury marked cells contribute to each stage of the developing HO anlagen and coexpress markers of endochondral ossification (Osterix, SOX9). Furthermore, these adult preinjury restricted cells coexpressed mesenchymal stem cell markers including PDGFRα, Sca1, and S100A4 in HO. When constitutively active ACVR1 (caACVR1) was expressed in scx-cre cells in the absence of injury (Scx-cre/caACVR1fl/fl ), tendons and joints formed HO. Postnatal lineage-restricted, tamoxifen-inducible caACVR1 expression (Scx-creERT2/caACVR1fl/fl ) was sufficient to form HO after directed cardiotoxin-induced muscle injury. These findings suggest that cells expressing scleraxis within muscle or tendon contribute to HO in the setting of both trauma or hyperactive BMP receptor (e.g., caACVR1) activity. Stem Cells 2017;35:705-710.
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Davis EL, Sonnet C, Lazard ZW, Henslee G, Gugala Z, Salisbury EA, Strecker EV, Davis TA, Forsberg JA, Davis AR, Olmsted‐Davis EA. Location-dependent heterotopic ossification in the rat model: The role of activated matrix metalloproteinase 9. J Orthop Res 2016; 34:1894-1904. [PMID: 26919547 PMCID: PMC5001934 DOI: 10.1002/jor.23216] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/23/2016] [Indexed: 02/04/2023]
Abstract
Extremity amputation or traumatic injury can often lead to the formation of heterotopic ossification (HO). Studies to induce HO in rat muscle using cell-based gene therapy show that this process appears to be location dependent. In the present study, HO was induced in mice and rats through injection of immunologically matched cells transduced with either a replication-defective adenovirus possessing bone morphogenetic protein 2 (BMP2) or an empty adenovirus vector (control). Injection in rat near the skeletal bone resulted in HO, whereas cells injected into the same muscle group but distal from the bone did not result in bone formation. When cells were injected in the same limb at both locations at the same time, HO was formed at both sites. Characterization of the bone formation in rats versus mice demonstrated that different sources of osteogenic progenitors were involved, which may account for the location dependent bone formation observed in the rat. Further experimentation has shown that a potential reason for this difference may be the inability of rat to activate matrix metalloproteinase 9 (MMP9), an essential protease in mice necessary for recruitment of progenitors. Inhibition of active MMP9 in mice led to a significant decrease in HO. The studies reported here provide insight into the mechanisms and pathways leading to bone formation in different animals and species. It appears that not all animal models are appropriate for testing HO therapies, and our studies also challenge the conventional wisdom that larger animal models are better for testing treatments affecting bone. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1894-1904, 2016.
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Pavey GJ, Qureshi AT, Tomasino AM, Honnold CL, Bishop DK, Agarwal S, Loder S, Levi B, Pacifici M, Iwamoto M, Potter BK, Davis TA, Forsberg JA. Targeted stimulation of retinoic acid receptor-γ mitigates the formation of heterotopic ossification in an established blast-related traumatic injury model. Bone 2016; 90:159-67. [PMID: 27368930 PMCID: PMC5546218 DOI: 10.1016/j.bone.2016.06.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/24/2016] [Accepted: 06/26/2016] [Indexed: 10/21/2022]
Abstract
Heterotopic ossification (HO) involves formation of endochondral bone at non-skeletal sites, is prevalent in severely wounded service members, and causes significant complications and delayed rehabilitation. As common prophylactic treatments such as anti-inflammatory drugs and irradiation cannot be used after multi-system combat trauma, there is an urgent need for new remedies. Previously, we showed that the retinoic acid receptor γ agonist Palovarotene inhibited subcutaneous and intramuscular HO in mice, but those models do not mimic complex combat injury. Thus, we tested Palovarotene in our validated rat trauma-induced HO model that involves blast-related limb injury, femoral fracture, quadriceps crush injury, amputation and infection with methicillin-resistant Staphylococcus aureus from combat wound infections. Palovarotene was given orally for 14days at 1mg/kg/day starting on post-operative day (POD) 1 or POD-5, and HO amount, wound dehiscence and related processes were monitored for up to 84days post injury. Compared to vehicle-control animals, Palovarotene significantly decreased HO by 50 to 60% regardless of when the treatment started and if infection was present. Histological analyses showed that Palovarotene reduced ectopic chondrogenesis, osteogenesis and angiogenesis forming at the injury site over time, while fibrotic tissue was often present in place of ectopic bone. Custom gene array data verified that while expression of key chondrogenic and osteogenic genes was decreased within soft tissues of residual limb in Palovarotene-treated rats, expression of cartilage catabolic genes was increased, including matrix metalloproteinase-9. Importantly, Palovarotene seemed to exert moderate inhibitory effects on wound healing, raising potential safety concerns related to dosing and timing. Our data show for the first time that Palovarotene significantly inhibits HO triggered by blast injury and associated complications, strongly indicating that it may prevent HO in patients at high risk such as those sustaining combat injuries and other forms of blast trauma.
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Agarwal S, Drake J, Qureshi AT, Loder S, Li S, Shigemori K, Peterson J, Cholok D, Forsberg JA, Mishina Y, Davis TA, Levi B. Characterization of Cells Isolated from Genetic and Trauma-Induced Heterotopic Ossification. PLoS One 2016; 11:e0156253. [PMID: 27494521 PMCID: PMC4975503 DOI: 10.1371/journal.pone.0156253] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/11/2016] [Indexed: 12/13/2022] Open
Abstract
Heterotopic ossification (HO) is the pathologic formation of bone separate from the normal skeleton. Although several models exist for studying HO, an understanding of the common in vitro properties of cells isolated from these models is lacking. We studied three separate animal models of HO including two models of trauma-induced HO and one model of genetic HO, and human HO specimens, to characterize the properties of cells derived from tissue containing pre-and mature ectopic bone in relation to analogous mesenchymal cell populations or osteoblasts obtained from normal muscle tissue. We found that when cultured in vitro, cells isolated from the trauma sites in two distinct models exhibited increased osteogenic differentiation when compared to cells isolated from uninjured controls. Furthermore, osteoblasts isolated from heterotopic bone in a genetic model of HO also exhibited increased osteogenic differentiation when compared with normal osteoblasts. Finally, osteoblasts derived from mature heterotopic bone obtained from human patients exhibited increased osteogenic differentiation when compared with normal bone from the same patients. These findings demonstrate that across models, cells derived from tissues forming heterotopic ossification exhibit increased osteogenic differentiation when compared with either normal tissues or osteoblasts. These cell types can be used in the future for in vitro investigations for drug screening purposes.
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Bhardwaj N, Pavlick AC, Ernstoff MS, Hanks BA, Albertini MR, Luke JJ, Yellin MJ, Keler T, Davis TA, Crocker A, Vitale L, Morishima C, Friedlander PA, Cheever MA, Fling S. A Phase II Randomized Study of CDX-1401, a Dendritic Cell Targeting NY-ESO-1 Vaccine, in Patients with Malignant Melanoma Pre-Treated with Recombinant CDX-301, a Recombinant Human Flt3 Ligand. J Clin Oncol 2016. [DOI: 10.1200/jco.2016.34.15_suppl.9589] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abstract
Heterotopic ossification--a complication of severe burns, head or blast injuries, and orthopaedic trauma--can result from altered adenosine metabolism in mesenchymal stem cells in response to elevated extracellular ATP (Peterson et al., this issue).
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Reardon DA, Desjardins A, Schuster J, Tran DD, Fink KL, Nabors LB, Li G, Bota DA, Lukas RV, Ashby LS, Duic JP, Mrugala MM, Werner A, Vitale L, He Y, Green J, Yellin MJ, Turner CD, Davis TA, Sampson JH. IMCT-08ReACT: LONG-TERM SURVIVAL FROM A RANDOMIZED PHASE II STUDY OF RINDOPEPIMUT (CDX-110) PLUS BEVACIZUMAB IN RELAPSED GLIOBLASTOMA. Neuro Oncol 2015. [DOI: 10.1093/neuonc/nov218.08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Alfieri KA, Potter BK, Davis TA, Wagner MB, Elster EA, Forsberg JA. Preventing Heterotopic Ossification in Combat Casualties-Which Models Are Best Suited for Clinical Use? Clin Orthop Relat Res 2015; 473:2807-13. [PMID: 25917420 PMCID: PMC4523530 DOI: 10.1007/s11999-015-4302-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND To prevent symptomatic heterotopic ossification (HO) and guide primary prophylaxis in patients with combat wounds, physicians require risk stratification methods that can be used early in the postinjury period. There are no validated models to help guide clinicians in the treatment for this common and potentially disabling condition. QUESTIONS/PURPOSES We developed three prognostic models designed to estimate the likelihood of wound-specific HO formation and compared them using receiver operating characteristic (ROC) curve analysis and decision curve analysis (DCA) to determine (1) which model is most accurate; and (2) which technique is best suited for clinical use. METHODS We obtained muscle biopsies from 87 combat wounds during the first débridement in the United States, all of which were evaluated radiographically for development of HO at a minimum of 2 months postinjury. The criterion for determining the presence of HO was the ability to see radiographic evidence of ectopic bone formation within the zone of injury. We then quantified relative gene expression from 190 wound healing, osteogenic, and vascular genes. Using these data, we developed an Artificial Neural Network, Random Forest, and a Least Absolute Shrinkage and Selection Operator (LASSO) Logistic Regression model designed to estimate the likelihood of eventual wound-specific HO formation. HO was defined as any HO visible on the plain film within the zone of injury. We compared the models accuracy using area under the ROC curve (area under the curve [AUC]) as well as DCA to determine which model, if any, was better suited for clinical use. In general, the AUC compares models based solely on accuracy, whereas DCA compares their clinical utility after weighing the consequences of under- or overtreatment of a particular disorder. RESULTS Both the Artificial Neural Network and the LASSO logistic regression models were relatively accurate with AUCs of 0.78 (95% confidence interval [CI], 0.72-0.83) and 0.75 (95% CI, 0.71-0.78), respectively. The Random Forest model returned an AUC of only 0.53 (95% CI, 0.48-0.59), marginally better than chance alone. Using DCA, the Artificial Neural Network model demonstrated the highest net benefit over the broadest range of threshold probabilities, indicating that it is perhaps better suited for clinical use than the LASSO logistic regression model. Specifically, if only patients with greater than 25% risk of developing HO received prophylaxis, for every 100 patients, use of the Artificial Network Model would result in six fewer patients who unnecessarily receive prophylaxis compared with using the LASSO regression model while not missing any patients who might benefit from it. CONCLUSIONS Our findings suggest that it is possible to risk-stratify combat wounds with regard to eventual HO formation early in the débridement process. Using these data, the Artificial Neural Network model may lead to better patient selection when compared with the LASSO logistic regression approach. Future prospective studies are necessary to validate these findings while focusing on symptomatic HO as the endpoint of interest. LEVEL OF EVIDENCE Level III, prognostic study.
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Pavey GJ, Qureshi AT, Hope DN, Pavlicek RL, Potter BK, Forsberg JA, Davis TA. Bioburden Increases Heterotopic Ossification Formation in an Established Rat Model. Clin Orthop Relat Res 2015; 473:2840-7. [PMID: 25822455 PMCID: PMC4523512 DOI: 10.1007/s11999-015-4272-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Heterotopic ossification (HO) develops in a majority of combat-related amputations wherein early bacterial colonization has been considered a potential early risk factor. Our group has recently developed a small animal model of trauma-induced HO that incorporates many of the multifaceted injury patterns of combat trauma in the absence of bacterial contamination and subsequent wound colonization. QUESTIONS/PURPOSES We sought to determine if (1) the presence of bioburden (Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus [MRSA]) increases the magnitude of ectopic bone formation in traumatized muscle after amputation; and (2) what persistent effects bacterial contamination has on late microbial flora within the amputation site. METHODS Using a blast-related HO model, we exposed 48 rats to blast overpressure, femur fracture, crush injury, and subsequent immediate transfemoral amputation through the zone of injury. Control injured rats (n = 8) were inoculated beneath the myodesis with phosphate-buffered saline not containing bacteria (vehicle) and treatment rats were inoculated with 1 × 10(6) colony-forming units of A baumannii (n = 20) or MRSA (n = 20). All animals formed HO. Heterotopic ossification was determined by quantitative volumetric measurements of ectopic bone at 12-weeks postinjury using micro-CT and qualitative histomorphometry for assessment of new bone formation in the residual limb. Bone marrow and muscle tissue biopsies were collected from the residual limb at 12 weeks to quantitatively measure the bioburden load and to qualitatively determine the species-level identification of the bacterial flora. RESULTS At 12 weeks, we observed a greater volume of HO in rats infected with MRSA (68.9 ± 8.6 mm(3); 95% confidence interval [CI], 50.52-85.55) when compared with A baumannii (20.9 ± 3.7 mm(3); 95% CI, 13.61-28.14; p < 0.001) or vehicle (16.3 ± 3.2 mm(3); 95% CI, 10.06-22.47; p < 0.001). Soft tissue and marrow from the residual limb of rats inoculated with A baumannii tested negative for A baumannii infection but were positive for other strains of bacteria (1.33 × 10(2) ± 0.89 × 10(2); 95% CI, -0.42 × 10(2)-3.08 × 10(2) and 1.25 × 10(6) ± 0.69 × 10(6); 95% CI, -0.13 × 10(6)-2.60 × 10(6) colony-forming units in bone marrow and muscle tissue, respectively), whereas tissue from MRSA-infected rats contained MRSA only (4.84 × 10(1) ± 3.22 × 10(1); 95% CI, -1.47 × 10(1)-11.1 × 10(1) and 2.80 × 10(7) ± 1.73 × 10(7); 95% CI, -0.60 × 10(7)-6.20 × 10(7) in bone marrow and muscle tissue, respectively). CONCLUSIONS Our findings demonstrate that persistent infection with MRSA results in a greater volume of ectopic bone formation, which may be the result of chronic soft tissue inflammation, and that early wound colonization may be a key risk factor. CLINICAL RELEVANCE Interventions that mitigate wound contamination and inflammation (such as early débridement, systemic and local antibiotics) may also have a beneficial effect with regard to the mitigation of HO formation and should be evaluated with that potential in mind in future preclinical studies.
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MESH Headings
- Acinetobacter baumannii/pathogenicity
- Amputation, Surgical
- Animals
- Bacterial Load
- Biopsy
- Blast Injuries/complications
- Colony Count, Microbial
- Disease Models, Animal
- Femoral Fractures/complications
- Male
- Methicillin-Resistant Staphylococcus aureus/pathogenicity
- Muscle, Skeletal/diagnostic imaging
- Muscle, Skeletal/injuries
- Muscle, Skeletal/microbiology
- Muscle, Skeletal/pathology
- Ossification, Heterotopic/diagnosis
- Ossification, Heterotopic/microbiology
- Osteogenesis
- Rats, Sprague-Dawley
- Risk Factors
- Staphylococcal Infections/diagnosis
- Staphylococcal Infections/microbiology
- Time Factors
- Wound Infection/diagnosis
- Wound Infection/microbiology
- X-Ray Microtomography
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