[Show abstract][Hide abstract] ABSTRACT: Pathologic extraskeletal bone formation, or heterotopic ossification (HO), occurs following mechanical trauma, burns, orthopedic operations, and in patients with hyperactivating mutations of the type I bone morphogenetic protein receptor ACVR1 (Activin type 1 receptor). Extraskeletal bone forms through an endochondral process with a cartilage intermediary prompting the hypothesis that hypoxic signaling present during cartilage formation drives HO development and that HO precursor cells derive from a mesenchymal lineage as defined by Paired related homeobox 1 (Prx). Here we demonstrate that Hypoxia inducible factor-1α (Hif1α), a key mediator of cellular adaptation to hypoxia, is highly expressed and active in three separate mouse models: trauma-induced, genetic, and a hybrid model of genetic and trauma-induced HO. In each of these models, Hif1α expression coincides with the expression of master transcription factor of cartilage, Sox9 [(sex determining region Y)-box 9]. Pharmacologic inhibition of Hif1α using PX-478 or rapamycin significantly decreased or inhibited extraskeletal bone formation. Importantly, de novo soft-tissue HO was eliminated or significantly diminished in treated mice. Lineage-tracing mice demonstrate that cells forming HO belong to the Prx lineage. Burn/tenotomy performed in lineage-specific Hif1α knockout mice (Prx-Cre/Hif1α(fl:fl)) resulted in substantially decreased HO, and again lack of de novo soft-tissue HO. Genetic loss of Hif1α in mesenchymal cells marked by Prx-cre prevents the formation of the mesenchymal condensations as shown by routine histology and immunostaining for Sox9 and PDGFRα. Pharmacologic inhibition of Hif1α had a similar effect on mesenchymal condensation development. Our findings indicate that Hif1α represents a promising target to prevent and treat pathologic extraskeletal bone.
Full-text · Article · Dec 2015 · Proceedings of the National Academy of Sciences
[Show abstract][Hide abstract] ABSTRACT: This review explores the series of published analyses from Massachusetts General Hospital to better understand how changes in medical specialization of burn medicine likely enabled the most important increase in survival from burns in the past 70 years.
Seventy years ago, survival from the most serious burn injuries was not possible even in the most advanced countries until critical advances were introduced. Insights into those few medical advances that actually impacted survival might be better understood from the consideration of a continuous series of survival analyses over 7 decades at Massachusetts General Hospital.
Mortality data from previously reported probit and logit analyses from thousands of patients treated at Massachusetts General Hospital were reviewed. A comparison of mortality from these prior mortality analyses from a more recent multicenter study and a national data set was performed.
The only giant leap forward in survival occurred during the 1970s, with no improvement during either the preceding or subsequent 30-year intervals. Despite the many modern advances that have been added to the care of these patients since 1984, although these may have represented medical progress, these advances did not impact survival.
Survival rates from burn injury may have been maximized by current treatment approaches within medical centers of excellence in burn medicine. Further efforts to improve the quality of life of survivors of burn injury should ultimately have very favorable impact upon the long-term outcomes in these patients who now survive such devastating injuries.
No preview · Article · Mar 2014 · Annals of surgery
[Show abstract][Hide abstract] ABSTRACT: Introduction: The impact of burn size on mortality is well
known, but empiric measurement of the association of burn size
with long-term functional outcomes remains poorly studied.
Methods: This five year (2003-8) prospective multi-center
study included burned adults ages 19-30 years who completed
the Young Adult Burn Outcome Questionnaire (YABOQ) at
initial contact, 10 days, and at 6, 12, 24, and 36 months after
initial questionnaire administration. Non-burned subjects of
comparable ages also completed the questionnaire as a reference
group. The association between functional recovery and total
body surface area (TBSA) burned was analyzed longitudinally
using generalized linear models with the generalized estimation
equation (GEE) technique. Functional status was characterized
in 15 domains: physical function, fine motor function, pain,
itch, social function limited by physical function, perceived
appearance, social function limited by appearance, sexual
function, emotion, family function, family concern, satisfaction
with symptom relief, satisfaction with role, work reintegration,
and religion. Domain scores were standardized to a mean of 50
and a standard deviation of 10 based on non-burned controls.
Results: There were 153 burned and 112 nonburned subjects
with a total of 620 questionnaires. TBSA burned was 11+14%
(Mean+SD); 31% had face involvement and 57% had hand
involvement. The lag from burn injury to questionnaire
administration was on average 7+7.7months, with a maximum
of 36 months. Lower recovery levels were associated with
increasing burn size for physical function, pain, itch, work
reintegration, emotion, satisfaction with symptom relief,
satisfaction with role, family function, and family concern
(p-value ranged from 0.04 to <0.0001).
Conclusions: Decrements in the outcomes of long term
functional recovery levels in young adult burn survivors were
associated with increasing burn size.
Applicability of Research to Practice: Expectations for
multidimensional recovery from burns in young adults can be
benchmarked based on burn size.
External Funding: This work is partially funded by the National
Institute of Disability and Rehabilitation Research.
No preview · Article · Jan 2014 · Journal of burn care & research: official publication of the American Burn Association
[Show abstract][Hide abstract] ABSTRACT: The optimal concentration of mafenide acetate solution for use in the treatment of burns is unknown. Despite data supporting the use of a 2.5% solution, 5% formulation is traditionally used, and has been the highest-costing medication on formulary. The aim of the current study is to evaluate cost and patient outcomes associated with a new policy implementing the use of 2.5% solution in burn patients and restricting the 5% formulation to specific indications only. A retrospective review of all patients receiving mafenide acetate solution at a single pediatric burn hospital was performed before and after the initiation of the new policy on the use of 5 vs 2.5% solution. Duration of therapy, adverse events, cost, incidence of wound infection, and bacteremia were analyzed. In 2009, 69 patients were treated with 5% mafenide acetate solution for a total cost of $125,000 ($1811 per patient). In 2010, after the initiation of the policy, 48 patients were treated: 19 received 5% mafenide acetate solution with appropriate indication, whereas the remaining 29 received 2.5% solution for a total cost of $38,632 ($804 per patient). There were no significant changes in the incidence of bacteremia or wound infection. No side effects of either solution were noted. Under certain conditions, a 2.5% mafenide acetate solution appears sufficient. In this multinational pediatric burn hospital, the use of a 2.5% solution was not associated with increased bacteremia or wound infection, and proved to be more cost-effective.
No preview · Article · Sep 2013 · Journal of burn care & research: official publication of the American Burn Association
[Show abstract][Hide abstract] ABSTRACT: Objectives: We Previously identified brain regions with decreased immediate early gene (IEG) expression in isolation reared (IR) rats ( Levine et al., 2008). In the current study, effects of burn injury on brain FDG uptake were evaluated in Group reared (GR) and Isolation reared (IR) rats. If FDG PET findings correlate with the genetic changes, they could serve as a biomarker in translational studies aimed at linking findings in isolation reared animals to clinical studies of patients presenting with symptoms due to early psychosocial deprivation.
Methods: A total of 12 male rats were obtained on post natal day (PN) 17 with lactating dams and were housed as in our prior studies (Levine et al., 2008). On PN 21, 1/2 of the animals were subjected to 20% dorsal burn in 90 degree water for 8 sec or sham treatment. The IR rats were then housed individually and the GR rats were housed in groups (Levine et al., 2007). On PN 49 the rats were fasted for 24 h, anaesthetized with isoflurane/N2O2, positioned in to a custom fabricated head holder, injected with FDG (1.0 mCi via tail vein) and brain images of 5 min. duration were acquired with a Siemens focus 220 (PET/CT. Images were reconstructed using the OSEM 3D/MAP algorithm with zoom 6 (256 x 256 matrix) and ROIs (SUV) were constructed for whole brain and multiple regions.
Results: The FDG PET results are summarized in the Table. For whole brain, FDG uptake in sham rats was neatly identical for IR and GR animals (p=NS). In contrast, whole brain FDG PET SUV was reduced by ~53% and IR ~ 68% for GR (p<0.001) and IR (p<0.001) animals at 28 days after burn injury . Similar reduction in FDG PET SUV were observed for thalamus, cerebellum, frontal cortex, parietal cortex and putamen.
Conclusions: The finding of FDG SUV differences, suggest the possibility that metabolic changes that can be measured in vivo using PET can be used as a biomarker of molecular changes that have previously only been accessible by ex-vivo measurements.
[Show abstract][Hide abstract] ABSTRACT: Skeletal muscle wasting is an exacerbating factor in the prognosis of critically ill patients. Using a systemic burn injury model in mice, we have established a role of autophagy in the resulting muscle wasting distant from the burn trauma. We provide evidence that burn injury increases the autophagy turnover in the distal skeletal muscle by conventional post-mortem tissue analyses and by a novel in vivo microscopic method using an autophagy reporter gene (tandem fluorescent LC3). The effect of tadalafil, a phosphodiesterase 5 inhibitor (PDE5I), on burn-induced skeletal muscle autophagy is documented and extends our published results that PDE5Is attenuates muscle degeneration in a muscular dystrophy model. We also designed a translational experiment to examine the impact of PDE5I on whole body and demonstrated the improvement of muscle atrophy, microcirculatory disturbance, and the survival rate after burn injury.
Preview · Article · Mar 2013 · AJP Endocrinology and Metabolism
[Show abstract][Hide abstract] ABSTRACT: Increasing evidence indicates that bacterial quorum sensing (QS) signals are important mediators of immunomodulation. However, whether microbes utilize these immunomodulatory signals to maintain infection remain unclear. Here, we show that the Pseudomonas aeruginosa QS-regulated molecule 2-amino acetophenone (2-AA) modulates host immune responses in a manner that increases host ability to cope with this pathogen. Mice treated with 2-AA prior to infection had a 90% survival compared to 10% survival rate observed in the non-pretreated infected mice. Whilst 2-AA stimulation activates key innate immune response pathways involving mitogen-activated protein kinases (MAPKs), nuclear factor (NF)-κB, and pro-inflammatory cytokines, it attenuates immune response activation upon pretreatment, most likely by upregulating anti-inflammatory cytokines. 2-AA host pretreatment is characterized by a transcriptionally regulated block of c-JUN N-terminal kinase (JNK) and NF-κB activation, with relatively preserved activation of extracellular regulated kinase (ERK) 1/2. These kinase changes lead to CCAAT/enhancer-binding protein-β (c/EBPβ) activation and formation of the c/EBPβ-p65 complex that prevents NF-κB activation. 2-AA's aptitude for dampening the inflammatory processes while increasing host survival and pathogen persistence concurs with its ability to signal bacteria to switch to a chronic infection mode. Our results reveal a QS immunomodulatory signal that promotes original aspects of interkingdom communication. We propose that this communication facilitates pathogen persistence, while enabling host tolerance to infection.
[Show abstract][Hide abstract] ABSTRACT: There have been few studies on costs of burn treatment. Furthermore, quantifying the actual cost of care at the patient level is hindered by anomalies of our insurance system. This article presents a practical method for determining the cost of caring for pediatric burn patients, using a cohort of patients from the Multi-Center Benchmarking Study at the Shriners Hospitals for Children-Boston and allows an estimate of resource use that may be linked to need or to best practices, without the confounding variable of inconsistent billing practices.
We estimated the cost of hospitalization for a cohort of 230 pediatric patients who sustained burn injuries. In a simulation of billing patterns of all US hospitals between 2001 and 2009, we applied Shriners Hospitals for Children use data to two external sources of cost information. For the hospital component of costs, we used the Healthcare Cost and Utilization Project Kid's Inpatient Database, and for the physician component of costs, we used the Medicare fee schedule.
Patients had a mean of 1.9 hospitalizations over 3 to 4 years. The mean total cost of hospitalization was $83,535 per patient, and the median total cost was $16,331 in 2006 dollars.
This is the first effort to estimate the early hospital costs of caring for children and young adults with burns in specialty hospitals and to establish a referent for quantifying the cost of caring for patients with acute burns. It lays the groundwork for studies relating costs of specific interventions to their effects on patient-centered outcomes.
[Show abstract][Hide abstract] ABSTRACT: Despite ongoing improvements in resuscitation, care, and outcomes, traumatic injury remains a significant health care and economic burden. The causes are multifactorial, but our approach to the clinical management of these patients remains limited by our current understanding of the pathobiology of the disease. A multicenter, multidisciplinary program known as the “Inflammation and the Host Response to Injury” Large Scale Collaborative Research Program was created by the National Institute of General Medical Sciences (NIGMS, U54 GM062119-10) in 2001 in a 10-year effort to address some of these issues. Its primary goal is to describe the human genomic response to severe trauma and burns, and to examine changes in gene expression in the context of different clinical outcomes. The Program has not only successfully implemented clinical care guidelines for managing the severe trauma patient based on the best available evidence to minimize iatrogenic variability, but it has also examined the genome-wide, immune-inflammatory response in total and isolated blood leukocyte populations. This review will address current milestones as well as future directions for the Program.
No preview · Article · Dec 2011 · European Journal of Trauma and Emergency Surgery
[Show abstract][Hide abstract] ABSTRACT: Excessive proinflammatory activation after trauma plays a role in late morbidity and mortality, including the development of multiple organ dysfunction syndrome (MODS). To date, identification of patients at risk has been challenging. Results from animal and human studies suggest that circulating interleukin 6 (IL-6) may serve as a biomarker for excessive inflammation. The purpose of this analysis was to determine the association of IL-6 with outcome in a multicenter developmental cohort and in a single-center validation cohort. Severely injured patients with shock caused by hemorrhage were evaluated within a multicenter developmental cohort (n = 79). All had blood drawn within 12 h of injury. Plasma IL-6 was determined by multiplex proteomic analysis. Clinical and outcome data were prospectively obtained. Within this developmental cohort, a plasma IL-6 level was determined for the subsequent development of MODS by developing a receiver operating curve and defining the optimal IL-6 level using the Youden Index. This IL-6 level was then evaluated within a separate validation cohort (n = 56). A receiver operating curve was generated for IL-6 and MODS development, with an IL-6 level of 350 pg/mL having the highest sensitivity and specificity within the developmental cohort. IL-6 was associated with MODS after adjusting for Acute Physiology and Chronic Health Evaluation, Injury Severity Score, male sex, and blood transfusions with an odds ratio of 3.9 (95% confidence interval, 1.33 - 11.19). An IL-6 level greater than 350 pg/mL within the validation cohort was associated with an increase in MODS score, MODS development, ventilator days, intensive care unit length of stay, and hospital length of stay. However, this IL-6 level was not associated with either the development of nosocomial infection or mortality. Elevation in plasma IL-6 seems to correlate with a poor prognosis. This measurement may be useful as a biomarker for prognosis and serve to identify patients at higher risk of adverse outcome that would benefit from novel therapeutic interventions.
Full-text · Article · Oct 2010 · Shock (Augusta, Ga.)
[Show abstract][Hide abstract] ABSTRACT: Time-course microarray experiments are capable of capturing dynamic gene expression profiles. It is important to study how these dynamic profiles depend on the multiple factors that characterize the experimental condition under which the time course is observed. Analytic methods are needed to simultaneously handle the time course and factorial structure in the data. We developed a method to evaluate factor effects by pooling information across the time course while accounting for multiple testing and nonnormality of the microarray data. The method effectively extracts gene-specific response features and models their dependency on the experimental factors. Both longitudinal and cross-sectional time-course data can be handled by our approach. The method was used to analyze the impact of age on the temporal gene response to burn injury in a large-scale clinical study. Our analysis reveals that 21% of the genes responsive to burn are age-specific, among which expressions of mitochondria and immunoglobulin genes are differentially perturbed in pediatric and adult patients by burn injury. These new findings in the body's response to burn injury between children and adults support further investigations of therapeutic options targeting specific age groups. The methodology proposed here has been implemented in R package "TANOVA" and submitted to the Comprehensive R Archive Network at http://www.r-project.org/. It is also available for download at http://gluegrant1.stanford.edu/TANOVA/.
Full-text · Article · Jun 2010 · Proceedings of the National Academy of Sciences
[Show abstract][Hide abstract] ABSTRACT: Endotoxemia plays an important role in the pathogenesis of sepsis and is accompanied by dysregulated apoptosis of immune and non-immune cells. Treatment with statins reduces mortality in rodent models of sepsis and endotoxemia. Inhibition of protein isoprenylation, including farnesylation, has been proposed as a mechanism to mediate the lipid-lowering-independent effects of statins. Nonetheless, the effects of the inhibition of isoprenylation have not yet been studied. To investigate the role of farnesylation, we evaluated the effects of farnesyltransferase inhibitor and statin on survival following lipopolysaccharide (LPS) challenge in mice. Both simvastatin (2mg/kg BW) and FTI-277 (20mg/kg BW) treatment improved survival by twofold after LPS injection, as compared with vehicle alone (p<0.01). LPS-induced cleavage (activation) of caspase-3, an indicator of apoptotic change, and increased protein expression of proapoptotic molecules, Bax and Bim, and activation of c-Jun NH(2)-terminal kinase (JNK/SAPK) in the liver and spleen were attenuated by both simvastatin and FTI-277. These results demonstrate that farnesyltransferase inhibitor as well as statin significantly reduced LPS-induced mortality in mice. Our findings also suggest that inhibition of protein farnesylation may contribute to the lipid-lowering-independent protective effects of statins in endotoxemia, and that protein farnesylation may play a role in LPS-induced stress response, including JNK/SAPK activation, and apoptotic change. Our data argue that farnesyltransferase may be a potential molecular target for treating patients with endotoxemia.
Full-text · Article · Jan 2010 · Biochemical and Biophysical Research Communications