Showing papers by "Ronald G. Tompkins published in 2017"

iNOS as a Driver of Inflammation and Apoptosis in Mouse Skeletal Muscle after Burn Injury: Possible Involvement of Sirt1 S-Nitrosylation-Mediated Acetylation of p65 NF-κB and p53.

Abstract: Inflammation and apoptosis develop in skeletal muscle after major trauma, including burn injury, and play a pivotal role in insulin resistance and muscle wasting. We and others have shown that inducible nitric oxide synthase (iNOS), a major mediator of inflammation, plays an important role in stress (e.g., burn)-induced insulin resistance. However, it remains to be determined how iNOS induces insulin resistance. Moreover, the interrelation between inflammatory response and apoptosis is poorly understood, although they often develop simultaneously. Nuclear factor (NF)-κB and p53 are key regulators of inflammation and apoptosis, respectively. Sirt1 inhibits p65 NF-κB and p53 by deacetylating these transcription factors. Recently, we have shown that iNOS induces S-nitrosylation of Sirt1, which inactivates Sirt1 and thereby increases acetylation and activity of p65 NF-κB and p53 in various cell types, including skeletal muscle cells. Here, we show that iNOS enhances burn-induced inflammatory response and apoptotic change in mouse skeletal muscle along with S-nitrosylation of Sirt1. Burn injury induced robust expression of iNOS in skeletal muscle and gene disruption of iNOS significantly inhibited burn-induced increases in inflammatory gene expression and apoptotic change. In parallel, burn increased Sirt1 S-nitrosylation and acetylation and DNA-binding capacity of p65 NF-κB and p53, all of which were reversed or ameliorated by iNOS deficiency. These results indicate that iNOS functions not only as a downstream effector but also as an upstream enhancer of burn-induced inflammatory response, at least in part, by Sirt1 S-nitrosylation-dependent activation (acetylation) of p65 NF-κB. Our data suggest that Sirt1 S-nitrosylation may play a role in iNOS-mediated enhanced inflammatory response and apoptotic change, which, in turn, contribute to muscle wasting and supposedly to insulin resistance after burn injury.

Prevention of Burn-Induced Inflammatory Responses and Muscle Wasting by GTS-21, a Specific Agonist for α7 Nicotinic Acetylcholine Receptors.

Abstract: Introduction:Muscle wasting (MW) in catabolic conditions (e.g., burn injury [BI]) is a major risk factor affecting prognosis. Activation of interleukin-1β (IL-1β)/nuclear factor-kappa B (NF-κB), interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3), and/or forkhead

Quantifying risk factors for long-term sleep problems after burn injury in young adults

Abstract: Restorative sleep is an important component of quality of life. Disturbances in sleep after burn injury were reported but all based on uncontrolled or nonstandardized data. The occurrence and the effect of long-term sleep problems in young adult burn survivors have not been well defined. This 5-year (2003-2008) prospective multicenter longitudinal study included adults with burn injuries ages 19 to 30 years who completed the Young Adult Burn Outcome Questionnaire (YABOQ) up to 36 months after injury. The items measured 15 patient-reported outcomes including physical, psychological, and social statuses and symptoms such as itch and pain. Scores of these 15 YABOQ outcome domains were standardized to a mean of 50 and a SD of 10 based on an age-matched nonburned reference group of young adults. Sleep quality was assessed using the item 'How satisfied are you now with your sleep,' rated by a 5-point Likert scale. Patients responding with very and somewhat dissatisfied were classified as having sleep dissatisfaction and the remaining as less or not dissatisfied. The associations between sleep dissatisfaction (yes/no) and YABOQ outcome domains were analyzed longitudinally using mixed-effect generalized linear models, adjusted for %TBSA burned, age, gender, and race. Generalized estimating equations were used to take into account correlated error resulting from repeated surveys on each patient over time. One hundred and fifty-two burn survivors participated in the YABOQ survey at baseline and during the follow-up who had at least one survey with a response to the sleep item. Among them, sleep dissatisfaction was twice as prevalent (76/152, 50%) when compared with the nonburned reference group (29/112, 26%). The likelihood of a burn survivor being dissatisfied with sleep was reduced over time after the burn injury. Sleep dissatisfaction following burns was significantly associated, in a dose-dependent manner, with increasing burn size (P = .001). Better sleep was associated with better outcomes in all domains (P < .05) except Fine Motor Function, and this association was significantly more apparent in the longer term compared with the shorter term with the same domains (P < .05). Dissatisfaction with sleep is highly prevalent following burn injuries in young adults. Lower satisfaction with sleep is associated with poorer scores in nearly all quality of life measures. Satisfaction with sleep should be addressed during the long-term clinical follow-up of young adults with burn injuries. Further research should be undertaken to understand the components of sleep quality that are important to burn survivors and which ones might be modified and tested in future intervention studies.

Burn-induced muscle metabolic derangements and mitochondrial dysfunction are associated with activation of HIF-1α and mTORC1: Role of protein farnesylation

Abstract: Metabolic derangements are a clinically significant complication of major trauma (e.g., burn injury) and include various aspects of metabolism, such as insulin resistance, muscle wasting, mitochondrial dysfunction and hyperlactatemia. Nonetheless, the molecular pathogenesis and the relation between these diverse metabolic alterations are poorly understood. We have previously shown that burn increases farnesyltransferase (FTase) expression and protein farnesylation and that FTase inhibitor (FTI) prevents burn-induced hyperlactatemia, insulin resistance, and increased proteolysis in mouse skeletal muscle. In this study, we found that burn injury activated mTORC1 and hypoxia-inducible factor (HIF)-1α, which paralleled dysfunction, morphological alterations (i.e., enlargement, partial loss of cristae structure) and impairment of respiratory supercomplex assembly of the mitochondria, and ER stress. FTI reversed or ameliorated all of these alterations in burned mice. These findings indicate that these burn-induced changes, which encompass various aspects of metabolism, may be linked to one another and require protein farnesylation. Our results provide evidence of involvement of the mTORC1-HIF-1α pathway in burn-induced metabolic derangements. Our study identifies protein farnesylation as a potential hub of the signaling network affecting multiple aspects of metabolic alterations after burn injury and as a novel potential molecular target to improve the clinical outcome of severely burned patients.

Technical Advance: Changes in neutrophil migration patterns upon contact with platelets in a microfluidic assay

Abstract: Neutrophils are traditionally regarded as the "first responders" of the immune system. However, recent observations revealed that platelets often respond earlier to recruit and activate neutrophils within sites of injury and inflammation. Currently, platelet-neutrophil interactions are studied by intravital microscopy. Although such studies provide exceptional, physiologic in vivo data, they are also laborious and have low throughput. To accelerate platelet-neutrophil interaction studies, we have developed and optimized an ex vivo microfluidic platform with which the interactions between platelets and moving neutrophils are measured at single-cell level in precise conditions and with high throughput. With the use of this new assay, we have evaluated changes in neutrophil motility upon direct contact with platelets. Motility changes include longer distances traveled, frequent changes in direction, and faster neutrophil velocities compared with a standard motility response to chemoattractant fMLP. We also found that the neutrophil-platelet direct interactions are transient and mediated by CD62P-CD162 interactions, localized predominantly at the uropod of moving neutrophils. This "crawling," oscillatory neutrophil behavior upon platelet contact is consistent with previous in vivo studies and validates the use of this new test for the exploration of this interactive relationship.

An ALPHA7 Nicotinic Acetylcholine Receptor Agonist (GTS-21) Promotes C2C12 Myonuclear Accretion in Association with Release of Interleukin-6 (IL-6) and Improves Survival in Burned Mice.

Abstract: The role of interleukin-6 (IL-6) in physiological processes and disease is poorly understood. The hypothesis tested in this study was that selective alpha7 acetylcholine receptor (α7AChR) agonist, GTS-21, releases IL-6 in association with myonuclear accretion and enhances insulin signaling i

KERIS: kaleidoscope of gene responses to inflammation between species

Abstract: A cornerstone of modern biomedical research is the use of animal models to study disease mechanisms and to develop new therapeutic approaches In order to help the research community to better explore the similarities and differences of genomic response between human inflammatory diseases and murine models, we developed KERIS: kaleidoscope of gene responses to inflammation between species (available at http://wwwigenomedorg/keris/) As of June 2016, KERIS includes comparisons of the genomic response of six human inflammatory diseases (burns, trauma, infection, sepsis, endotoxin and acute respiratory distress syndrome) and matched mouse models, using 2257 curated samples from the Inflammation and the Host Response to Injury Glue Grant studies and other representative studies in Gene Expression Omnibus A researcher can browse, query, visualize and compare the response patterns of genes, pathways and functional modules across different diseases and corresponding murine models The database is expected to help biologists choosing models when studying the mechanisms of particular genes and pathways in a disease and prioritizing the translation of findings from disease models into clinical studies

Development of clinical process measures for pediatric burn care: Understanding variation in practice patterns.

Abstract: BACKGROUND There has been little systematic examination of variation in pediatric burn care clinical practices and its effect on outcomes. As a first step, current clinical care processes need to be operationally defined. The highly specialized burn care units of the Shriners Hospitals for Children system present an opportunity to describe the processes of care. The aim of this study was to develop a set of process-based measures for pediatric burn care and examine adherence to them by providers in a cohort of pediatric burn patients. METHODS We conducted a systematic literature review to compile a set of process-based indicators. These measures were refined by an expert panel of burn care providers, yielding 36 process-based indicators in four clinical areas: initial evaluation and resuscitation, acute excisional surgery and critical care, psychosocial and pain control, and reconstruction and aftercare. We assessed variability in adherence to the indicators in a cohort of 1,076 children with burns at four regional pediatric burn programs in the Shriners Hospital system. The percentages of the cohort at each of the four sites were as follows: Boston, 20.8%; Cincinnati, 21.1%; Galveston, 36.0%; and Sacramento, 22.1%. The cohort included children who received care between 2006 and 2010. RESULTS Adherence to the process indicators varied both across sites and by clinical area. Adherence was lowest for the clinical areas of acute excisional surgery and critical care, with a range of 35% to 48% across sites, followed by initial evaluation and resuscitation (range, 34%-60%). In contrast, the clinical areas of psychosocial and pain control and reconstruction and aftercare had relatively high adherence across sites, with ranges of 62% to 93% and 71% to 87%, respectively. Of the 36 process indicators, 89% differed significantly in adherence between clinical sites (p < 0.05). Acute excisional surgery and critical care exhibited the most variability. CONCLUSION The development of this set of process-based measures represents an important step in the assessment of clinical practice in pediatric burn care. Substantial variation was observed in practices of pediatric burn care. However, further research is needed to link these process-based measures to clinical outcomes. LEVEL OF EVIDENCE Therapeutic/care management, level IV.

Local and Systemic Changes Associated with Long-term, Percutaneous, Static Implantation of Titanium Alloys in Rhesus Macaques ( Macaca mulatta ).

Abstract: Metal alloys are frequently used as implant materials in veterinary medicine. Recent studies suggest that many alloys induce both local and systemic inflammatory responses. In this study, 37 rhesus macaques with long-term skull-anchored percutaneous titanium alloy implants (duration, 0 to 14 y) were evaluated for changes in their hematology, coagulation, and serum chemistry profiles. Negative controls (n = 28) did not have implants. Macaques with implants had higher plasma D-dimer and lower antithrombin III concentrations than nonimplanted animals. In addition, animals with implants had higher globulin and lower albumin and calcium concentrations compared with nonimplanted macaques. Many of these changes were positively correlated with duration of implantation and the number of implants. Chronic bacterial infection of the skin was present around many of the implant sites and within deeper tissues. Representative histopathology around the implant site of 2 macaques revealed chronic suppurative to pyogranulomatous inflammation extending from the skin to the dura mater. X-ray fluorescence microscopy of tissue biopsies from the implant site of the same 2 animals revealed significantly higher levels of free metal ions in the tissue, including titanium and iron. The higher levels of free metal ions persisted in the tissues for as long as 6 mo after explantation. These results suggest that long-term skull-anchored percutaneous titanium alloy implants can be associated with localized inflammation, chronic infection, and leaching of metal ions into local tissues.

Addressing the Missing Part of Evidence-based Practice: The Importance of Respecting Clinical Judgment in the Process of Adopting a New Screening Tool for Postpartum Depression.

Abstract: The aim of the present study was to examine the role of nurse's clinical judgment in the uptake of an evidence-based tool assessing postpartum depression, the Edinburgh Postpartum Depression Scale. Nurses in a home visitation program were being asked to regularly screen for postpartum depression. The screener was introduced as a new standard of practice for nurses. A qualitative investigation of the nurses' reactions in addition to an evidence-based screener was conducted. Prior to and during the implementation, several meetings were held with the nurses and the research team to discuss the nurses' experience with the tool. Nurses participated in semi-structured interviews and notes were reviewed to identify themes that may be useful in further understanding evidence-based practice in nurses' home visitation. It was found that the process of uptake included three phases: dissatisfaction with the utility of the tool; problem solving and integration of clinical judgment into a complementary instrume...

A Method to Localize Occult Infections

Abstract: C ommonly, in the care of the critically ill patient, localization and anatomic delineation of an occult infectious or inflammatory focus is essential to direct further therapeutic management. An infectious or inflammatory focus can be considered occult when the usual imaging modalities (including conventional radiography, computed tomography, and ultrasonography) have failed to delineate the site and extent of the process. Although in these cases, “inflammation scanning” using Ga-citrate and “In-labeled leukocytes has occasionally been useful, more often these techniques have had very limited clinical utility. In 1988, Fischman et al’ described a method to localize focal sites of infection and inflammation using human immunoglobulin (Ig) C coupled to “In with the chelating agent diethylenetriamine pontaacetic acid (DTPA). Using this method, Rubin et a12 in 1989 described findings in 128 patients thought to have focal infections with the indications for study shown in Table 1. In 51 patients, localization of “In..labeled IgC correlated with clinical findings of abdominal or pelvic infections (21 patients), intravascular infections (11 patients), pulmonary infections (7), and skeletal infections (12) (Table 2). No focal localization of “In-labeled IgG was

Adult-onset, chronic, cyclic thrombocytopenia in a Rhesus macaque (

Abstract: An 8-year-old, male Rhesus macaque (Macaca mulatta), previously used for dengue virus (DENV) vaccine research with viral challenge, was presented with adult-onset, chronic, cyclic thrombocytopenia. Platelet number, morphology, and function were evaluated by automated hematology, peripheral blood smears, electron microscopy, flow cytometry, and impedance aggregometry. Bone marrow was evaluated by cytology. Both serum anti-dengue nonstructural protein 1 (NS1) antibodies and anti-platelet antibodies were detected by ELISA. Platelet characterization showed a lack of aggregation to all agonists (ADP, ASP, and collagen), increased activation with increased expression of surface marker (HLA-ABC), and an absence of surface receptor GPIX during clinical episodes of petechiae and ecchymoses, even in the presence of normal platelet counts. Bone marrow aspirates identified potential mild megakaryocytic hypoplasia. All platelet functions and morphologic attributes were within normal limits during clinically normal phases. Presence of anti-dengue NS1 serum antibodies confirmed a positive DENV titer 8 years postvaccination. Based on the history and clinical findings, a primary differential diagnosis for this chronic, cyclic platelet pathology was autoimmune platelet destruction with potential bone marrow involvement.

Adult-onset, chronic, cyclic thrombocytopenia in a Rhesus macaque (Macaca mulatta) after dengue virus vaccination and viral challenge.

Abstract: An 8-year-old, male Rhesus macaque (Macaca mulatta), previously used for dengue virus (DENV) vaccine research with viral challenge, was presented with adult-onset, chronic, cyclic thrombocytopenia Platelet number, morphology, and function were evaluated by automated hematology, peripheral blood smears, electron microscopy, flow cytometry, and impedance aggregometry Bone marrow was evaluated by cytology Both serum anti-dengue nonstructural protein 1 (NS1) antibodies and anti-platelet antibodies were detected by ELISA Platelet characterization showed a lack of aggregation to all agonists (ADP, ASP, and collagen), increased activation with increased expression of surface marker (HLA-ABC), and an absence of surface receptor GPIX during clinical episodes of petechiae and ecchymoses, even in the presence of normal platelet counts Bone marrow aspirates identified potential mild megakaryocytic hypoplasia All platelet functions and morphologic attributes were within normal limits during clinically normal phases Presence of anti-dengue NS1 serum antibodies confirmed a positive DENV titer 8 years postvaccination Based on the history and clinical findings, a primary differential diagnosis for this chronic, cyclic platelet pathology was autoimmune platelet destruction with potential bone marrow involvement