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Thermal injury is often associated with a proinflammatory state resulting in serious complications. After a burn, the innate immune system is activated with subsequent immune cell infiltration and cytokine production. Although the innate immune response is typically beneficial, an excessive activation leads to cytokine storms, multiple organ failure, and even death. This overwhelming immune response is regulated by damage-associated molecular patterns (DAMPs). DAMPs are endogenous molecules that are actively secreted by immune cells or passively released by dead or dying cells that can bind to pathogen recognition receptors in immune and nonimmune cells. Recent studies involving animal models along with human studies have drawn great attention to the possible pathological role of DAMPs as an immune consequence of thermal injury. In this review, we outline DAMPs and their function in thermal injury, shedding light on the mechanism of sterile inflammation during tissue injury and identifying new immune targets for treating thermal injury.
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Queimaduras/imunologia , Sistema Imunitário/imunologia , Imunidade Inata/imunologia , Inflamação/imunologia , Animais , Síndrome da Liberação de Citocina/imunologia , HumanosRESUMO
BACKGROUND: Cardiac dysfunction is a major component of sepsis-induced multiorgan failure in critical care units. Changes in cardiac autophagy and its role during sepsis pathogenesis have not been clearly defined. Targeted autophagy-based therapeutic approaches for sepsis are not yet developed. METHODS: Beclin-1-dependent autophagy in the heart during sepsis and the potential therapeutic benefit of targeting this pathway were investigated in a mouse model of lipopolysaccharide (LPS)-induced sepsis. RESULTS: LPS induced a dose-dependent increase in autophagy at low doses, followed by a decline that was in conjunction with mammalian target of rapamycin activation at high doses. Cardiac-specific overexpression of Beclin-1 promoted autophagy, suppressed mammalian target of rapamycin signaling, improved cardiac function, and alleviated inflammation and fibrosis after LPS challenge. Haplosufficiency for beclin 1 resulted in opposite effects. Beclin-1 also protected mitochondria, reduced the release of mitochondrial danger-associated molecular patterns, and promoted mitophagy via PTEN-induced putative kinase 1-Parkin but not adaptor proteins in response to LPS. Injection of a cell-permeable Tat-Beclin-1 peptide to activate autophagy improved cardiac function, attenuated inflammation, and rescued the phenotypes caused by beclin 1 deficiency in LPS-challenged mice. CONCLUSIONS: These results suggest that Beclin-1 protects the heart during sepsis and that the targeted induction of Beclin-1 signaling may have important therapeutic potential.
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Autofagia , Proteína Beclina-1/metabolismo , Sepse/patologia , Animais , Autofagia/efeitos dos fármacos , Modelos Animais de Doenças , Lipopolissacarídeos/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Miocárdio/metabolismo , Miocárdio/patologia , PTEN Fosfo-Hidrolase/metabolismo , Sepse/etiologia , Proteína Sequestossoma-1/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Ubiquitina-Proteína Ligases/metabolismoRESUMO
This article introduces the Consumer Ear Disease Risk Assessment (CEDRA) tool. CEDRA is a brief questionnaire designed to screen for targeted ear diseases. It offers an opportunity for consumers to self-screen for disease before seeking a hearing device and may be used by clinicians to help their patients decide the appropriate path to follow in hearing healthcare. Here we provide highlights of previously published validation in the context of a more thorough description of CEDRA's development and implementation. CEDRA's sensitivity and specificity, using a cut-off score of 4 or higher, was 90% and 72%, respectively, relative to neurotologist diagnoses in the initial training sample used to create the scoring algorithm (n = 246). On a smaller independent test sample (n = 61), CEDRA's sensitivity and specificity were 76% and 80%, respectively. CEDRA has readability levels similar to many other patient-oriented questionnaires in hearing healthcare, and informal reports from pilot CEDRA-providers indicate that the majority of patients can complete it in less than 10 min. As the hearing healthcare landscape changes and provider intercession is no longer mandated, CEDRA provides a measure of safety without creating a barrier to access.
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Otopatias/diagnóstico , Acessibilidade aos Serviços de Saúde , Auxiliares de Audição , Perda Auditiva/reabilitação , Humanos , Programas de Rastreamento , Reprodutibilidade dos Testes , Medição de Risco , Sensibilidade e Especificidade , Inquéritos e QuestionáriosRESUMO
OBJECTIVES: The purpose of this study was to evaluate the specificity and sensitivity of two red flag protocols in detecting ear diseases associated with changes in hearing. DESIGN: The presence of red-flag symptoms was determined in a chart review of 307 adult patients from the Mayo Clinic Florida Departments of Otorhinolaryngology and Audiology. Participants formed a convenience sample recruited for a separate study. Neurotologist diagnosis was the criterion for comparisons. RESULTS: Of the 251 patient files retained for analysis, 191 had one or more targeted diseases and 60 had age- or noise-related hearing loss. Food and Drug Administration red flags sensitivity was 91% (confidence interval [CI], 86 to 95%) and specificity was 72% (CI, 59 to 83%). American Academy of Otolaryngology-Head and Neck Surgery red flags sensitivity was 98% (CI, 95 to 99%) and specificity was 20% (CI, 11 to 32%). CONCLUSIONS: Stakeholders must determine which diseases are meaningful contraindications for hearing aid use and whether these red-flag protocols have acceptable levels of sensitivity and specificity. As direct-to-consumer models of hearing devices increase, a disease detection method that does not require provider intercession would be useful.
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Contraindicações , Auxiliares de Audição , Perda Auditiva/diagnóstico , Testes Auditivos , Adulto , Idoso , Análise Custo-Benefício , Feminino , Regulamentação Governamental , Perda Auditiva/reabilitação , Humanos , Masculino , Programas de Rastreamento/economia , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Estados Unidos , United States Food and Drug AdministrationRESUMO
Mitochondria-derived danger-associated molecular patterns (DAMPs) play important roles in sterile inflammation after acute injuries. This study was designed to test the hypothesis that 17ß-estradiol protects the heart via suppressing myocardial mitochondrial DAMPs after burn injury using an animal model. Sprague-Dawley rats were given a third-degree scald burn comprising 40% total body surface area (TBSA). 17ß-Estradiol, 0.5 mg/kg, or control vehicle was administered subcutaneously 15 min following burn. The heart was harvested 24 h postburn. Estradiol showed significant inhibition on the productivity of H2O2 and oxidation of lipid molecules in the mitochondria. Estradiol increased mitochondrial antioxidant defense via enhancing the activities and expression of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Estradiol also protected mitochondrial respiratory function and structural integrity. In parallel, estradiol remarkably decreased burn-induced release of mitochondrial cytochrome c and mitochondrial DNA (mtDNA) into cytoplasm. Further, estradiol inhibited myocardial apoptosis, shown by its suppression on DNA laddering and downregulation of caspase 1 and caspase 3. Estradiol's anti-inflammatory effect was demonstrated by reduction in systemic and cardiac cytokines (TNF-α, IL-1ß, and IL-6), decrease in NF-κB activation, and attenuation of the expression of inflammasome component ASC in the heart of burned rats. Estradiol-provided cardiac protection was shown by reduction in myocardial injury marker troponin-I, amendment of heart morphology, and improvement of cardiac contractility after burn injury. Together, these data suggest that postburn administration of 17ß-estradiol protects the heart via an effective control over the generation of mitochondrial DAMPs (mtROS, cytochrome c, and mtDNA) that incite cardiac apoptosis and inflammation.
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Queimaduras/fisiopatologia , Cardiotônicos/uso terapêutico , Citocromos c/metabolismo , DNA Mitocondrial/metabolismo , Estradiol/uso terapêutico , Mitocôndrias Cardíacas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Apoptose/efeitos dos fármacos , Queimaduras/complicações , Cardiotônicos/farmacologia , Caspases/metabolismo , Citocinas/metabolismo , Estradiol/farmacologia , Glutationa Peroxidase/metabolismo , Cardiopatias/etiologia , Cardiopatias/metabolismo , Cardiopatias/prevenção & controle , Peróxido de Hidrogênio/metabolismo , Masculino , Mitocôndrias Cardíacas/efeitos dos fármacos , Modelos Animais , NF-kappa B/metabolismo , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismoRESUMO
The medical community seeks to provide evidence-based guidelines for treating any disease to ensure optimal care delivery. Occasionally, a patient's unique physiology does not respond to guideline-driven treatments and requires experienced clinical personalization for treatment. Failure of clinicians to recognize patient outliers and augment care can delay treatment, provide substandard care, and potentially threaten a patient's life. This paper describes a clinical caveat for treating profound or persistent hypokalemia in patients with DKA (diabetic ketoacidosis).
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OBJECTIVE: Damage associated molecular patterns (DAMPs) are pathological mediators linking local tissue damage to systemic inflammation in various diseases. Some DAMPs, such as mitochondrial DNA (mtDNA), can be recognized by the cytoplasmic cGAS protein to trigger the activation of the stimulator of interferon genes (STING)-dependent innate immune pathway responsible for infection or sterile inflammation. The objective of our study was to evaluate the association between circulating mtDNA and cGAS-STING pathway activation in mediating inflammation following burn injury. METHODS: 48 adult Sprague-Dawley male rats were divided into eight groups (Sham, 2, 4, 8, 12, 24, 48, 72 h after burn injury). The animals underwent 40% total body surface area scald injury to produce a full-thickness burn. Plasma samples were collected via cardiac puncture under deep anesthesia. Tissues were harvested and placed in formalin, followed by paraffin embedment. Total plasma DNA was isolated followed by measurement of mtDNA using quantitative polymerase chain reaction. Haemotoxylin-Eosin stain and Western blot was used for lung histology and protein assays, respectively. Statistical analyses were performed using ANOVA and student's t-test and represented as mean ± s.d. RESULTS: Plasma mtDNA trended upward at early time-points following burn injury with peak levels at 8 h after burn when compared to the control group (345 ± 83.4 copies/µl vs. 239 ± 43.1 copies/µl, p = 0.07) and followed a bell-shaped distribution. Lung slices from burned rats showed acute injury marked by increased inflammatory infiltrate, with the maximum changes seen at 24 h, accompanied with significant upregulation of neutrophil elastase (p = 0.04). Compared with sham animals, cGAS and STING protein levels in lung tissue were up-regulated at 4 and 8 h after burn (p = 0.03 and p < 0.001, respectively). CONCLUSION: Activation of the cGAS-STING pathway by increased plasma mtDNA is an important pathway driving neutrophil infiltration in burn-induced acute lung injury in rats. A further understanding of the STING-mediated immunopathology in lung and other susceptible organs may be important for the development of novel therapies for burn injury.
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Lesão Pulmonar Aguda , Proteínas Adaptadoras de Transdução de Sinal , Queimaduras , Proteínas de Membrana , Nucleotidiltransferases , Lesão Pulmonar Aguda/complicações , Animais , Queimaduras/complicações , Inflamação/metabolismo , Masculino , Nucleotidiltransferases/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de SinaisRESUMO
OBJECTIVE: To describe the implementation of a department-wide research curriculum and infrastructure created to promote academic collaboration and productivity, particularly amongst trainees and junior investigators involved in basic, translational, clinical, quality, or education research. DESIGN: Description of UT Southwestern Medical Center's (UTSW) surgical research resources and infrastructure and the development of a didactic curriculum focused on research methods, writing skills, and optimizing academic time and effort. SETTING: The collaboration was initiated by UTSW Department of Surgery residents who were on dedicated research time (DRT) and grew to include trainees and faculty at all levels of the institution. Guest lecturers from institutions around the country were incorporated via virtual meeting platforms. PARTICIPANTS: Medical students, residents, and clinical and research faculty from the Department of Surgery were invited to attend research meetings, didactics, and the guest-lecture series. Additionally, all groups were given access to shared resources and encouraged to share their own work. RESULTS: A robust set of resources including data analysis tools, manuscript and grant writing templates, funding opportunities, and a comprehensive list of surgical conferences was created and made accessible to UTSW Surgery team members. Moreover, a curriculum of lectures covering a broad variety of topics for all types of research was created and has thus far reached an audience of over 40 UTSW Surgery trainees and staff. CONCLUSIONS: A comprehensive set of lectures and resources targeted toward facilitating surgical research was designed and implemented at one of the largest surgical training programs in the country. This effort represents a low-cost, feasible, and accessible way to improve academic productivity and enhance the training of surgeon-scientists and can serve as a blueprint for other institutions around the country.
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Internato e Residência , Currículo , HumanosRESUMO
In the setting of the raging COVID-19 pandemic, the search for innovative therapeutics is desperately sought after. As we learn more about the characteristics and metabolic health of patients and as our understanding of COVID-19 pathophysiology and treatment progresses, so is our understanding of medication effects that might increase disease severity. As of late, ACE inhibitors have been under investigation for a potential increase in illness severity due to ACE2 upregulation. Given our knowledge of other nutrient-pharmaceutical interactions, could the ACE inhibitor impact on COVID be due to something else? In this paper, we discuss the possibility that ACE inhibitors might be affecting COVID-19 patients by causing zinc insufficiency.KEY MESSAGESZinc deficiency caused by chronic ACE inhibitor usage may exacerbate the pathogenicity of COVID-19 in susceptible patients.A multi-center study is needed to assess the zinc levels of patients with COVID-19 who are taking ACE inhibitors and other medications that may result in low zinc levels.
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Enzima de Conversão de Angiotensina 2/metabolismo , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Tratamento Farmacológico da COVID-19 , Zinco/deficiência , Enzima de Conversão de Angiotensina 2/efeitos dos fármacos , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , COVID-19/diagnóstico , COVID-19/epidemiologia , COVID-19/virologia , Interações Medicamentosas , Feminino , Humanos , Masculino , Estado Nutricional/efeitos dos fármacos , Preparações Farmacêuticas , Fatores de Risco , SARS-CoV-2/genética , Índice de Gravidade de Doença , Zinco/sangueRESUMO
BACKGROUND: Almost 80 percent of adults in the United States have had cytomegalovirus (CMV) infection by age 40. The number of symptomatic CMV hepatitis cases has been increasing along with non-alcoholic fatty liver disease (NAFLD) cases in the United States that is estimated to be 25 percent of the population. In this paper, we try to link these two entities together. CASE SUMMARY: In this case report, we describe a young female who presented with fever, nausea, and vomiting who was found to have NAFLD and CMV hepatitis that was treated supportively. CONCLUSION: In this case report, we describe NAFLD as a risk factor for CMV hepatitis and discuss the possible impact on clinical practice. We believe, it is essential to consider NAFLD and it's disease mechanisms' localized immu-nosuppression, as a risk factor of CMV hepatitis and severe coronavirus disease 2019 infection.
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INTRODUCTION: Traditionally, lactated Ringer's solution (LR) has been utilized for the resuscitation of thermally injured patients via the Parkland or Brooke formulas. Both of these formulas include colloid supplementation after 24 h of resuscitation. Recently, the addition of albumin within the initial resuscitation has been reported to decrease fluid creep and hourly fluids given. Our institution has previously advocated for a crystalloid-driven resuscitation. Given reports of improved outcomes with albumin, we pragmatically adjusted these practices and present our findings for doing so. METHODS: Our burn registry, consisting of prospectively collected patient data, was queried for those at least 18 years of age who, between July 2017 and December 2018, sustained a thermal injury and completed a formal resuscitation (24 h). At the attending physician's discretion, rescue colloid was administered using 25% albumin for those failing to respond to traditional resuscitation (patients with sustained urine output of <0.5 mL/kg over 2-3 h, or unstable vital signs and ongoing fluid administration). We compared the total volume of the crystalloid-only and rescue colloid resuscitation fluids given to patients. We also examined the in/out fluid balances during resuscitation. Statistical analysis was performed using Stata software. RESULTS: A total of 91 patients with thermal injuries were included: the median age was 40 (IQR 31-57), 73% were male, and 30 patients received rescue albumin. The percentage of total body surface area burned (%TBSA) was greater in those who received rescue albumin (40.3% vs. 34%; p = 0.047). Despite a higher %TBSA in the albumin group, the total LR given during resuscitation was not significantly different between groups (15,914.43 mL vs. 11,828.71 mL; p = 0.129) even when normalized for TBSA and weight (ml LR/kg/%TBSA: 4.31 vs. 3.66; p = 0.129. The average in/out fluid ratio for the rescue group was higher than for the crystalloid group (0.83 ± 0.05 vs. 0.59 ± 0.11; p = 0.06) and returned to normal after colloid administration. CONCLUSION: Rescue albumin administration decreases the amount of fluid administered per %TBSA during resuscitation, and also increases end organ function as evidenced by increased urinary output. These effects occurred in patients who sustained larger burns and failed to respond to traditional crystalloid resuscitation. Our findings led us to modify our current protocol and a related prospective study of clinical outcomes.
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Queimaduras , Adulto , Queimaduras/terapia , Coloides/uso terapêutico , Hidratação/métodos , Humanos , Soluções Isotônicas/uso terapêutico , Masculino , Perfusão , Estudos Prospectivos , Ressuscitação/métodosRESUMO
On June 17 to 18, 2019, the American Burn Association, in conjunction with Underwriters Laboratories, convened a group of experts on burn resuscitation in Washington, DC. The goal of the meeting was to identify and discuss novel research and strategies to optimize the process of burn resuscitation. Patients who sustain a large thermal injury (involving >20% of the total body surface area [TBSA]) face a sequence of challenges, beginning with burn shock. Over the last century, research has helped elucidate much of the underlying pathophysiology of burn shock, which places multiple organ systems at risk of damage or dysfunction. These studies advanced the understanding of the need for fluids for resuscitation. The resultant practice of judicious and timely infusion of crystalloids has improved mortality after major thermal injury. However, much remains unclear about how to further improve and customize resuscitation practice to limit the morbidities associated with edema and volume overload. Herein, we review the history and pathophysiology of shock following thermal injury, and propose some of the priorities for resuscitation research. Recommendations include: studying the utility of alternative endpoints to resuscitation, reexamining plasma as a primary or adjunctive resuscitation fluid, and applying information about inflammation and endotheliopathy to target the underlying causes of burn shock. Undoubtedly, these future research efforts will require a concerted effort from the burn and research communities.
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Queimaduras/terapia , Cuidados Críticos/normas , Medicina Baseada em Evidências/normas , Ressuscitação/normas , Humanos , Insuficiência de Múltiplos Órgãos/prevenção & controle , Projetos de Pesquisa/normas , Choque Traumático/prevenção & controle , Sociedades Médicas/normasRESUMO
Neurologic injury is a known and feared complication of extracorporeal membrane oxygenation (ECMO). Neurologic biomarkers may have a role in assisting in early identification of such. Axonal biomarker tau has not been investigated in the pediatric ECMO population. The objective of this study is to evaluate plasma levels of tau in pediatric patients supported with ECMO. Eighteen patients requiring ECMO support in a quaternary pediatric intensive care unit at a university-affiliated children's hospital from October 2015 to February 2017 were enrolled. Patients undergoing extracorporeal cardiopulmonary resuscitation or recent history of bypass were excluded. Plasma tau was measured using enzyme-linked immunosorbent assay. Neuroimaging was reviewed for acute neurologic injury, and tau levels were analyzed to assess for correlation. Tau was significantly higher in ECMO patients than in control subjects. Sixty-one percent of subjects had evidence of acute brain injury on neuroimaging, but tau level did not correlate with injury. Subjects with multifocal injury all experienced infarction and had significantly higher tau levels on ECMO day 3 than patients with isolated injury. In addition, peak tau levels of neuro-injured subjects were compared with controls and noninjured ECMO subjects using receiver operating curve analysis. This study demonstrates preliminary evidence of axonal injury in pediatric ECMO patients.
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Lesões Encefálicas/epidemiologia , Oxigenação por Membrana Extracorpórea/efeitos adversos , Proteínas tau/sangue , Adolescente , Biomarcadores/sangue , Criança , Pré-Escolar , Oxigenação por Membrana Extracorpórea/métodos , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Projetos Piloto , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Severe burn leads to substantial skeletal muscle wasting that is associated with adverse outcomes and protracted recovery. The purpose of our study was to investigate muscle tissue homeostasis in response to severe burn. Muscle biopsies from the right m. lateralis were obtained from 10 adult burn patients at the time of their first operation. Patients were grouped by burn size (total body surface area of <30% vs ≥30%). Muscle fiber size and factors of cell death and muscle regeneration were examined. Muscle cell cross-sectional area was significantly smaller in the large-burn group (2174.3 ± 183.8 µm2 vs 3687.0 ± 527.2 µm2, P = .04). The expression of ubiquitin E3 ligase MuRF1 and cell death downstream effector caspace 3 was increased in the large-burn group (P < .05). No significant difference was seen between groups in expression of the myogenic factors Pax7, MyoD, or myogenin. Interestingly, Pax7 and proliferating cell nuclear antigen (PCNA) expression in muscle tissue were significantly correlated to injury severity only in the smaller-burn group (P < .05). In conclusion, muscle atrophy after burn is driven by apoptotic activation without an equal response of satellite cell activation, differentiation, and fusion.
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Queimaduras/metabolismo , Queimaduras/patologia , Homeostase/fisiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/etiologia , Adolescente , Adulto , Fatores Etários , Queimaduras/complicações , Caspase 3/metabolismo , Feminino , Humanos , Masculino , Proteínas Musculares/metabolismo , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Proteína MyoD/metabolismo , Miogenina/metabolismo , Fator de Transcrição PAX7/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Índice de Gravidade de Doença , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Adulto JovemRESUMO
Muscle wasting induced by severe burn worsens clinical outcomes is associated with hyperglycemia. A novel muscle-specific secretory factor, musclin, was reported to regulate glucose metabolism with a homologous sequence of natriuretic peptides. The purpose of the study was to investigate musclin expression in response to burn injury in both human and animal models. Serum was collected from 13 adult burn patients and circulating levels of musclin protein were measured via elisa. The cytokine profile was measured by Bio-Plex multiple immunoassay. Following the clinical study, we used a burn rat model with 40% TBSA to study the time course of musclin expression till day 14. Rat serum and muscle tissue sample were harvested. Finally, an in vitro study was applied to investigate whether the muscle cell C2C12 myoblast expressed musclin under 10% burn serum stimulation. Pearson analysis showed that there was a significant positive correlation of musclin expression to total body surface area of burn in patients (P &= .038). Musclin expression was significantly positively correlated with IL-4, IL-7, IL-12, and IL-13 in burn patients' serum (P < .05). In the animal study, we found that the musclin level evaluated at 6 hours and 1 day in burn rat serum (P < .05). In vitro, musclin mRNA expression significantly increased with burn serum stimulation at 24 hours (P < .05). In conclusion, serum level of musclin elevated both in human patients and burn animals; musclin was correlated with the severity of burn injury as well as with an elevated cytokine profile in patients; burn serum-stimulated musclin expression in vitro further identified the resource of musclin expression after burn.
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Queimaduras/sangue , Proteínas Musculares/sangue , Fatores de Transcrição/sangue , Adulto , Animais , Queimaduras/patologia , Técnicas de Cultura de Células , Citocinas/metabolismo , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Mioblastos/metabolismo , Ratos , Fatores de Tempo , Adulto JovemRESUMO
Severe burn causes systemic inflammation and hypercatabolism, resulting in damage to multiple organs distant to the burn site, including the musculoskeletal system. Bone mass and muscle loss have been reported. However, tendon that connects bone and muscle has not been studied in comparable detail. Here we aimed to characterize the molecular and functional changes in Achilles tendon triggered by severe burn. Forty male Sprague-Dawley rats received 40% total body surface area scald burn. Achilles tendons were collected up to 14 days postburn. Sham-treated animals served as a control group. We analyzed tendons for changes in expression of IL-6, IL-1ß, TNF, MMP9, MMP13, TGFß1, Collagens I and III, and for morphological and biomechanical changes. Gene expression of IL-6 and IL-1ß as well as MMP9 and MMP13 increased in rat tendon 3 days after burn. Col3a1 increased at day 3 and col1a1 at day 7. At day 14, TGFß1 increased, whereas the protein ratio for collagens I/III decreased, indicating tendon remodeling. Histological analysis with H&E and Picrosirius red staining further revealed a decrease in organized collagen fibers 14 days after burn. Biomechanical analysis showed a decrease in stiffness and ultimate force of tendons in burn rats.We conclude that tendinopathy was observed in Achilles tendon 14 days after severe burn, via the induction of inflammation and remodeling. The present study provides a model of tendinopathy that may be used for the development of therapeutic approaches after burn.
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Tendão do Calcâneo/metabolismo , Queimaduras/metabolismo , Tendão do Calcâneo/patologia , Animais , Queimaduras/patologia , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Inflamação/metabolismo , Inflamação/patologia , Masculino , Metaloproteinase 13 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Ratos , Ratos Sprague-Dawley , Índices de Gravidade do TraumaRESUMO
In the heart, thermal injury activates a group of intracellular cysteine proteases known as caspases, which have been suggested to contribute to myocyte inflammation and dyshomeostasis. In this study, Sprague-Dawley rats were given either a third-degree burn over 40% total body surface area plus conventional fluid resuscitation or sham burn injury. Experimental groups included 1) sham burn given vehicle, 400 microl DMSO; 2) sham burn given Q-VD-OPh (6 mg/kg), a highly specific and stable caspase inhibitor, 24 and 1 h prior to sham burn; 3) burn given vehicle, DMSO as above; 4) burn given Q-VD-OPh (6 mg/kg) 24 and 1 h prior to burn. Twenty-four hours postburn, hearts were harvested and studied with regard to myocardial intracellular sodium concentration, intracellular pH, ATP, and phosphocreatine (23Na/31P nuclear magnetic resonance); myocardial caspase-1, -3,and -8 expression; myocyte Na+ (fluorescent indicator, sodium-binding benzofurzan isophthalate); myocyte secretion of TNF-alpha, IL-1beta, IL-6, and IL-10; and myocardial performance (Langendorff). Burn injury treated with vehicle alone produced increased myocardial expression of caspase-1, -3, and -8, myocyte Na+ loading, cytokine secretion, and myocardial contractile depression; cellular pH, ATP, and phosphocreatine were stable. Q-VD-OPh treatment in burned rats attenuated myocardial caspase expression, prevented burn-related myocardial Na+ loading, attenuated myocyte cytokine responses, and improved myocardial contraction and relaxation. The present data suggest that signaling through myocardial caspases plays a pivotal role in burn-related myocyte sodium dyshomeostasis and myocyte inflammation, perhaps contributing to burn-related contractile dysfunction.
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Clorometilcetonas de Aminoácidos/farmacologia , Queimaduras/complicações , Inibidores de Caspase , Inibidores de Cisteína Proteinase/farmacologia , Cardiopatias/prevenção & controle , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Quinolinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Clorometilcetonas de Aminoácidos/uso terapêutico , Animais , Queimaduras/tratamento farmacológico , Queimaduras/metabolismo , Queimaduras/fisiopatologia , Cálcio/metabolismo , Caspase 1/metabolismo , Caspase 3/metabolismo , Caspase 8/metabolismo , Caspases/metabolismo , Inibidores de Cisteína Proteinase/uso terapêutico , Modelos Animais de Doenças , Cardiopatias/etiologia , Cardiopatias/metabolismo , Cardiopatias/fisiopatologia , Homeostase , Concentração de Íons de Hidrogênio , Interleucina-10/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Espectroscopia de Ressonância Magnética , Masculino , Miócitos Cardíacos/enzimologia , Miócitos Cardíacos/metabolismo , Fosfocreatina/metabolismo , Quinolinas/uso terapêutico , Ratos , Ratos Sprague-Dawley , Índice de Gravidade de Doença , Sódio/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Pressão Ventricular/efeitos dos fármacosRESUMO
BACKGROUND: Burn patients suffer muscle mass loss associated with hyperinflammation and hypercatabolism. The mitochondria are affected by this metabolic alteration. Mitochondrial fission activates a caspase cascade that ultimately leads to cell death. We postulate that burn-induced muscle loss is associated with increased mitochondrial fission and subsequent functional impairment. Further, we investigated whether the cytokine IL-6 plays a major role in mitochondrial fission-associated cell death after burn. METHODS: Murine myoblast C2C12 cells were treated with 10% serum isolated either from control rats or 40% total body surface area burned rats. Mitochondria were labeled with MitoTracker Green for live cell images. Mitochondrial function was assessed with an Enzo Mito-ID membrane potential cytotoxicity kit. Protein signals were detected by Western blot analysis. Moreover, recombinant IL-6 was applied to stimulate C2C12 to differentiate the role of cytokine IL-6; lastly, we treated burn serum-stimulated cells with IL-6 antibodies. RESULTS: Caspase 3 activity increased in C2C12 cells with burn serum stimulation, suggesting increased cell death in skeletal muscle after burn. Mitochondrial morphology shortened and mitochondrial membrane potential decreased in cells treated with burn serum. Western blot data showed that mitofusion-1 expression significantly decreased in burn serum-treated cells, supporting the morphologic observation of mitochondrial fission. Mitochondrial fragmentation increased with IL-6 stimulation, and IL-6 antibody decreased caspase 3 activity and mitochondrial membrane potential improved in burn serum-stimulated cells. CONCLUSION: Burn serum caused muscle cell death associated with increased mitochondrial fission and functional impairment. This alteration was alleviated with IL-6 antibody treatment, suggesting the cytokine plays a role in mitochondrial changes in muscle after systemic injury.
Assuntos
Queimaduras/sangue , Interleucina-6/metabolismo , Mitocôndrias Musculares/metabolismo , Mioblastos Esqueléticos/metabolismo , Soro , Animais , Morte Celular , Linhagem Celular , Camundongos , Mitocôndrias Musculares/patologia , Mioblastos Esqueléticos/patologiaRESUMO
The objective of our study was to examine the effects of isometric resistance training (IRT) on resting blood pressure in adults. We conducted a systematic review and meta-analysis of randomized-controlled trials lasting ⩾2 weeks, investigating the effects of isometric exercise on blood pressure in healthy adults (aged ⩾18 years), published in a peer-reviewed journal between 1 January 1966 to 31 January 2015. We included 11 randomized trials, totaling 302 participants. The following reductions were observed after isometric exercise training; systolic blood pressure (SBP) mean difference (MD) -5.20 mm Hg (95% confidence interval (CI) -6.08 to -4.33, P<0.00001); diastolic blood pressure (DBP) MD -3.91 mm Hg (95% CI -5.68 to -2.14, P<0.0001); and mean arterial blood pressure (MAP) MD -3.33 mm Hg (95% CI -4.01 to -2.66, P<0.00001). Sub-analyses showed males tended to reduce MAP MD -4.13 mm Hg (95% CI -5.08 to -3.18) more than females. Subjects aged ⩾45 years demonstrated larger reductions in MAP MD -5.51 mm Hg (95% CI -6.95 to -4.06) than those <45 years. Subjects undertaking ⩾8 weeks of IRT demonstrated a larger reduction in SBP MD -7.26 mm Hg (95% CI -8.47 to -6.04) and MAP MD -4.22 mm Hg (95% CI -5.08 to -3.37) than those undertaking<8 weeks. Hypertensive participants in IRT demonstrated a larger reduction in MAP MD -5.91 mm Hg (95% CI -7.94 to -3.87) than normotensive participants MD -3.01 mm Hg (95% CI -3.73 to -2.29). Our study indicated that IRT lowers SBP, DBP and MAP. The magnitude of effect may be larger in hypertensive males aged ⩾45 years, using unilateral arm IRT for >8 weeks.
Assuntos
Pressão Sanguínea , Exercício Físico/fisiologia , Hipertensão/terapia , Adulto , Idoso , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Educação Física e Treinamento , Caracteres SexuaisRESUMO
Classical antimicrobial drugs target proliferation and therefore place microbes under extreme selective pressure to evolve resistance. Alternative drugs that target bacterial virulence without impacting survival directly offer an attractive solution to this problem, but to date few such molecules have been discovered. We previously discovered a widespread group of bacterial adhesins, termed Multivalent Adhesion Molecules (MAMs) that are essential for initial binding of bacteria to host tissues and virulence. Thus, targeting MAM-based adherence is a promising strategy for displacing pathogens from host tissues and inhibiting infection. Here, we show that topical application of polymeric microbeads functionalized with the adhesin MAM7 to a burn infected with multidrug-resistant Pseudomonas aeruginosa substantially decreased bacterial loads in the wound and prevented the spread of the infection into adjacent tissues. As a consequence, the application of this adhesion inhibitor allowed for vascularization and wound healing, and maintained local and systemic inflammatory responses to the burn. We propose that MAM7-functionalized microbeads can be used as a topical treatment, to reduce bacterial attachment and hence prevent bacterial colonization and infection of wounds. As adhesion is not required for microbial survival, this anti-infective strategy has the potential to treat multidrug-resistant infections and limit the emergence of drug-resistant pathogens.