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1.
J Vasc Surg ; 56(5): 1468-9, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22975334
2.
Shock ; 36(2): 162-9, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21430603

RESUMO

Burn injury initiates an enhanced inflammatory condition referred to as the systemic inflammatory response syndrome or the two-hit response phenotype. Prior reports indicated that macrophages respond to injury and demonstrate a heightened reactivity to Toll-like receptor stimulation. Since we and others observed a significant increase in splenic GR-1 F4/80 CD11b macrophages in burn-injured mice, we wished to test if these macrophages might be the primary macrophage subset that shows heightened LPS reactivity. We report here that burn injury promoted higher level TNF-α expression in GR-1, but not GR-1 macrophages, after LPS activation both in vivo and ex vivo. We next tested whether CD4 T cells, which are known to suppress injury-induced inflammatory responses, might control the activation and expansion of GR-1 macrophages. Interestingly, we found that GR-1 macrophage expansion and LPS-induced TNF-α expression were not significantly different between wild-type and CD4 T cell-deficient CD4(-/-) mice. However, further investigations showed that LPS-induced TNF-α production was significantly influenced by CD4 T cells. Taken together, these data indicate that GR-1 F4/80 CD11b macrophages represent the primary macrophage subset that expands in response to burn injury and that CD4 T cells do not influence the GR-1 macrophage expansion process, but do suppress LPS-induced TNF-α production. These data suggest that modulating GR-1 macrophage activation as well as CD4 T cell responses after severe injury may help control the development of systemic inflammatory response syndrome and the two-hit response phenotype.


Assuntos
Queimaduras/imunologia , Queimaduras/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Receptores de Superfície Celular/metabolismo , Animais , Antígeno CD11b/metabolismo , Citometria de Fluxo , Lipopolissacarídeos/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fator de Necrose Tumoral alfa/metabolismo
3.
J Leukoc Biol ; 89(1): 137-47, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20884652

RESUMO

Injury initiates local and systemic host responses and is known to increase CD4 Treg activity in mice and humans. This study uses a TCR transgenic T cell adoptive transfer approach and in vivo Treg depletion to determine specifically the in vivo influence of Tregs on antigen-driven CD4 T cell reactivity following burn injury in mice. We report here that injury in the absence of recipient and donor Tregs promotes high antigen-driven CD4 T cell expansion and increases the level of CD4 T cell reactivity. In contrast, CD4 T cell expansion and reactivity were suppressed significantly in injured Treg-replete mice. In additional experiments, we found that APCs prepared from burn- or sham-injured, Treg-depleted mice displayed significantly higher antigen-presenting activity than APCs prepared from normal mice, suggesting that Tregs may suppress injury responses by controlling the intensity of APC activity. Taken together, these findings demonstrate that Tregs can actively control the in vivo expansion and reactivity of antigen-stimulated, naïve CD4 T cells following severe injury.


Assuntos
Queimaduras/imunologia , Antígenos CD4/imunologia , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Células Apresentadoras de Antígenos/imunologia , Antígeno B7-1/metabolismo , Antígeno B7-2/metabolismo , Queimaduras/patologia , Proliferação de Células , Células Dendríticas/metabolismo , Epitopos/imunologia , Linfonodos/imunologia , Ativação Linfocitária/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Modelos Imunológicos , Linfócitos T Reguladores/citologia , Células Th1/imunologia
4.
Proc Natl Acad Sci U S A ; 107(22): 9923-8, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20479259

RESUMO

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/.


Assuntos
Queimaduras/genética , Análise de Sequência com Séries de Oligonucleotídeos/estatística & dados numéricos , Adulto , Fatores Etários , Análise de Variância , Queimaduras/imunologia , Criança , Pré-Escolar , Estudos Transversais , Interpretação Estatística de Dados , Bases de Dados Genéticas , Feminino , Perfilação da Expressão Gênica/estatística & dados numéricos , Genes de Imunoglobulinas , Genes Mitocondriais , Humanos , Lactente , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Prognóstico , Software , Fatores de Tempo
5.
J Leukoc Biol ; 85(5): 862-70, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19228816

RESUMO

Severe injury disrupts normal immune regulation causing a transient hyperinflammatory reaction and suppressed adaptive immune function. This report addresses the potential contribution of dendritic cells (DC) to changes in adaptive immune function after injury by specifically measuring injury-induced changes in splenic DC numbers and subsets, cell-surface markers, TLR responses, and APC function. Using a mouse burn injury model, we found that injury did not markedly alter the relative percentage of lymphoid, myeloid, or plasmacytoid DC in the spleens of burn-injured mice. Moreover, we did not observe a significant reduction in cell-surface expression of several major costimulatory molecules, CD40, CD80, CD86, programmed death 1 ligand, ICOS ligand, and B7-H3, on DC. Instead, we observed increased cell-surface expression of CD86 at 1 day after injury with no significant changes in costimulatory molecule expression at 7 days after injury, suggesting that burn injury causes an early activation of DC. In addition, injury did not suppress DC reactivity to TLR2, TLR4, or TLR9 agonists. Most important, DC prepared from injured mice were able to present peptide antigen to naive OTII TCR transgenic CD4+ T cells as efficiently and effectively as DC from sham-injured mice. We also found that CD4 T cells stimulated with antigen presented by DC from sham or burn mice showed similar levels of IL-2, IFN-gamma, IL-10, and IL-13 production. Taken together, these findings support the conclusion that DC do not acquire a suppressive phenotype following severe injury in mice.


Assuntos
Apresentação de Antígeno/imunologia , Queimaduras/imunologia , Células Dendríticas/imunologia , Baço/citologia , Animais , Antígeno B7-2/imunologia , Antígeno B7-2/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Citocinas/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Baço/imunologia , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/imunologia , Células Th2/metabolismo , Receptores Toll-Like/imunologia
6.
J Vasc Surg ; 47(6): 1351-5, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18440184

RESUMO

The American Vascular Association/Lifeline Foundation is celebrating its 20th anniversary this year. This remarkable two-decade journey represents a cumulative effort by the leaders and members of the Society for Vascular Surgery (SVS). For the historical record, we would like to chart the sequence of events leading to various programs. In 1986, the Executive Council of SVS approved the formation of an Education/Research Foundation, from which the Lifeline Foundation evolved, with the mission to support the career development of young research-oriented vascular surgeons. Since that time, Lifeline has awarded 141 Student Fellowships, 21 Wylie Traveling Fellowships, 17 Mentored Clinical Scientist Development (K08) Awards, and three Mentored Patient-Oriented Research Career Development (K23) Awards. In 2001, the American Vascular Association (AVA) was established under the aegis of American Association for Vascular Surgery (formerly International Society for Cardiovascular Surgery-North American Chapter). In 2004, with the merger of the SVS and the American Association of Vascular Surgery into a single entity (SVS), Lifeline and the AVA merged into a single foundation, the AVA. As AVA/Lifeline is poised to launch a campaign for an endowment fund, we hope this report will let the members of the SVS know what has been accomplished, what we plan to do, and, most importantly, what we need to do in the future.


Assuntos
Pesquisa Biomédica , Fundações , Desenvolvimento de Programas , Sociedades Médicas , Procedimentos Cirúrgicos Vasculares , Aniversários e Eventos Especiais , Pesquisa Biomédica/economia , Pesquisa Biomédica/história , Bolsas de Estudo , Fundações/economia , Fundações/história , História do Século XX , História do Século XXI , Humanos , Desenvolvimento de Programas/economia , Apoio à Pesquisa como Assunto , Sociedades Médicas/economia , Sociedades Médicas/história , Estados Unidos , Procedimentos Cirúrgicos Vasculares/economia , Procedimentos Cirúrgicos Vasculares/história
7.
J Immunol ; 180(4): 2450-8, 2008 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18250454

RESUMO

Major injury is widely thought to predispose the injured host to opportunistic infections. This idea is supported by animal studies showing that major injury causes reduced resistance to polymicrobial sepsis induced by cecal ligation and puncture. Although cecal ligation and puncture represents a clinically relevant sepsis model, we wanted to test whether injury might also lead to greater susceptibility to peritoneal infection caused by a single common pathogen, Escherichia coli. Contrary to our expectation, we show herein that the LD(50) for sham-injured mice was 10(3) CFU of E. coli, whereas the LD(50) for burn-injured mice was 50 x 10(3) CFU at 7 days postinjury. This injury-associated enhanced resistance was apparent as early as 1 day after injury, and maximal resistance was observed at days 7 and 14. We found that burn-injured mice had higher numbers of circulating neutrophils and monocytes than did sham mice before infection and that injured mice were able to recruit greater numbers of neutrophils to the site of infection. Moreover, the peritoneal neutrophils in burn-injured mice were more highly activated than neutrophils from sham mice as determined by Mac-1 expression, superoxide generation, and bactericidal activity. Our findings suggest that the enhanced innate immune response that develops following injury, although it is commonly accepted as the mediator of the detrimental systemic inflammatory response syndrome, may also, in some cases, benefit the injured host by boosting innate immune antimicrobial defenses.


Assuntos
Queimaduras/imunologia , Queimaduras/microbiologia , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/prevenção & controle , Imunidade Inata , Animais , Líquido Ascítico/imunologia , Líquido Ascítico/microbiologia , Queimaduras/mortalidade , Infecções por Escherichia coli/mortalidade , Injeções Intraperitoneais , Dose Letal Mediana , Ativação de Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ativação de Neutrófilo/imunologia , Infecções Oportunistas/imunologia , Infecções Oportunistas/mortalidade , Infecções Oportunistas/prevenção & controle
8.
Physiol Genomics ; 32(3): 299-310, 2008 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-17986522

RESUMO

A primary objective of the large collaborative project entitled "Inflammation and the Host Response to Injury" was to identify leukocyte genes that are differentially expressed after two different types of injury in mouse models and to test the hypothesis that both forms of injury would induce similar changes in gene expression. We report here the genes that are expressed in white blood cells (WBCs) and in splenocytes at 2 h, 1 day, 3 days, and 7 days after burn and sham injury or trauma-hemorrhage (T-H) and sham T-H. Affymetrix Mouse Genome 430 2.0 GeneChips were used to profile gene expression, and the results were analyzed by dCHIP, BRB Array Tools, and Ingenuity Pathway Analysis (IPA) software. We found that the highest number of genes differentially expressed following burn injury were at day 1 for both WBCs (4,989) and for splenocytes (4,715) and at day 1 for WBCs (1,167) and at day 3 for splenocytes (1,117) following T-H. The maximum overlap of genes that were expressed after both forms of injury were at day 1 in WBCs (136 genes) and at day 7 in splenocytes (433 genes). IPA revealed that the cell-to-cell signaling, cell death, immune response, antiapoptosis, and cell cycle control pathways were affected most significantly. In summary, this report provides a database of genes that are modulated in WBCs and splenocytes at sequential time points after burn or T-H in mice and reveals that relatively few leukocyte genes are expressed in common after these two forms of injury.


Assuntos
Queimaduras/genética , Regulação da Expressão Gênica , Redes Reguladoras de Genes/genética , Hemorragia/genética , Leucócitos/metabolismo , Animais , Perda Sanguínea Cirúrgica , Perfilação da Expressão Gênica , Inflamação/genética , Masculino , Camundongos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Baço/patologia , Fatores de Tempo
9.
J Vasc Surg ; 45 Suppl A: A2-7, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17544018

RESUMO

The Lifeline Foundation/National Heart, Lung, and Blood Institute William J. von Liebig Mentored Clinical Scientist Development (K08) Award program was established as a unique partnership to support vascular surgeon-scientists. Between 1999 and 2005, 39 applications were submitted, and the overall funding rate was 49% (14 von Liebig K08s and 5 additional NHLBI K08s). Vascular surgeon K08 recipients (median age, 38 years) had held faculty appointments for 2.5 +/- 0.4 years, with 2.6 +/- 0.2 years of previous research experience and 28.4 +/- 6.2 publications. These individuals subsequently authored 5.1 +/- 0.8 peer-reviewed publications per recipient per year, of which 35% were research and 65% were clinical. Six of seven holding the K08 over 3 years had received academic promotion, and all five completing the 5-year award had achieved independent investigator status with National Institutes of Health support. The von Liebig K08 program has therefore been an effective vehicle to stimulate research career development in the field of vascular surgery.


Assuntos
Distinções e Prêmios , Pesquisa Biomédica , Bolsas de Estudo , Fundações , National Institutes of Health (U.S.) , Setor Privado/economia , Especialidades Cirúrgicas , Procedimentos Cirúrgicos Vasculares , Adulto , Pesquisa Biomédica/economia , Escolha da Profissão , Docentes de Medicina , Bolsas de Estudo/economia , Fundações/economia , Humanos , Manuscritos Médicos como Assunto , Mentores , National Institutes of Health (U.S.)/economia , Revisão da Pesquisa por Pares , Publicações Periódicas como Assunto , Avaliação de Programas e Projetos de Saúde , Salários e Benefícios , Especialidades Cirúrgicas/economia , Estados Unidos , Procedimentos Cirúrgicos Vasculares/economia
10.
Ann Surg ; 244(4): 514-23, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16998360

RESUMO

OBJECTIVES: We recently reported increased CD4 CD25 T regulatory (Treg) activity after burn injury in mice. This study sought to determine if Tregs mediate the reduction in TH1-type immunity after serious injury in man and if Treg function is altered by injury. METHODS: Peripheral blood was withdrawn from 19 consenting adult patients (35.1 +/- 16.3 years of age) with Injury Severity Scores (ISS) 36.6 +/- 13.9 on days 1 and 7 after trauma and from 5 healthy individuals. CD4 T cells were purified and sorted into Treg (CD25(high)) and Treg-depleted populations. After activation of cells with anti-CD3/CD28 antibody, production of the TH1-type cytokine IFNgamma, TH2-type cytokines (IL-4 and IL-5), and the inhibitory cytokine IL-10 was measured using cytometric bead arrays. Treg activity was measured by in vitro suppression of autologous CD4 T cell proliferation. RESULTS: All patients survived, 9 (47%) developed infection postinjury. IFNgamma production by patient CD4 T cells was decreased on day 1 and day 7, when compared with healthy controls. However, when Tregs were depleted from the CD4 T cells, the IFNgamma production increased to control levels. Tregs were the chief source of IL-4 and IL-5 as well as IL-10. Treg suppression of T cell proliferation increased significantly from day 1 to day 7 after injury. CONCLUSIONS: We demonstrate for the first time that human Tregs are increased in potency after severe injury. Most significantly, Tregs are important mediators of the suppression of T cell activation and the reduction in TH1 cytokine production found after injury.


Assuntos
Linfócitos T CD4-Positivos/fisiologia , Receptores de Interleucina-2 , Linfócitos T/fisiologia , Ferimentos e Lesões/imunologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Células Th1/imunologia , Ferimentos e Lesões/sangue
11.
Shock ; 25(2): 135-40, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16525351

RESUMO

Several reports have shown that burn injury primes the immune system for an early and vigorous proinflammatory CD4 T cell response, suggesting that injury might signal CD4 T cell activation. We addressed this possibility by investigating changes in CD4 T cell activation marker expression, proliferation, and T cell receptor (TCR) usage at several early time points after burn injury. Using a sensitive flow cytometry approach to measure changes in the expression of Ki-67 antigen, a nuclear protein detected only in proliferating cells, we observed an early burst of proliferation by lymph node, but not spleen, CD4 T cells 12 h after burn injury. In contrast, mice that were treated with the bacterial superantigen staphylococcal enterotoxin B (SEB) as a positive control for in vivo T cell activation did not show this early proliferation. Instead, we observed a significant increase in proliferating lymph node and spleen CD4 and CD8 T cells by 3 days after SEB treatment. Burn injury induced higher cell surface CD25 and CD152 expression on lymph node CD4 T cells, whereas SEB treatment increased CD25 and CD69 expression on CD4 and CD8 T cells. Finally, we found that burn injury induced a proliferative response at 12 h by an oligoclonal subset of TCR Vbeta-chain-expressing CD4 T cells (Vbeta4, Vbeta6, Vbeta11, and Vbeta14). Interestingly, CD4 T cells expressing the Vbeta11-TCR remained significantly increased in the lymph nodes 3 days after burn injury. Taken together, these findings indicate that burn injury induces an early proliferation and activation of CD4 T cells in the regional lymph nodes and that these proliferating cells show restricted TCR Vbeta-chain usage consistent with the idea that injury triggers an early T cell activation signal.


Assuntos
Queimaduras/imunologia , Linfócitos T CD4-Positivos/imunologia , Regulação da Expressão Gênica/imunologia , Linfonodos/imunologia , Ativação Linfocitária/imunologia , Animais , Antígenos CD/biossíntese , Antígenos CD/imunologia , Biomarcadores/metabolismo , Queimaduras/metabolismo , Queimaduras/patologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Proliferação de Células/efeitos dos fármacos , Enterotoxinas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Linfonodos/metabolismo , Linfonodos/patologia , Ativação Linfocitária/efeitos dos fármacos , Masculino , Camundongos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia
12.
Blood ; 107(11): 4399-406, 2006 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-16467203

RESUMO

Platelets play a fundamental role in maintaining hemostasis and have been shown to participate in innate and adaptive immunity. However, the role of platelets in the immune response to injury remains undefined. We tested the importance of platelets in the host response to serious injury in a newly developed platelet-deficient mouse model. Wild-type and platelet-depleted C57BL/6J mice underwent a 25% full-thickness total body surface area thermal or sham injury. Platelet-deficient mice showed survival of 51% at 48 hours after injury compared with 94% to 100% survival in experimental control mice (P < .001). Necropsy and histology ruled out hemorrhage and hypovolemia as causes of death. Percentages of peripheral blood monocytes (P < .01) and neutrophils (P < .05) were increased between 36 and 48 hours after thermal injury in platelet-deficient mice compared with control mice. Plasma levels of TNFalpha (P < .001), IL-6 (P < .001), and MCP-1 (P < .05) were also elevated by 24 hours whereas levels of TGFbeta(1) were reduced between 24 and 36 hours following injury in platelet-depleted mice (P < .001) compared with control mice. Our findings demonstrate for the first time that platelets play a critical protective role during the host response to injury. Moreover, our findings suggest that platelets and, more importantly, platelet-derived TGFbeta(1) modulate the systemic inflammatory response occurring after injury.


Assuntos
Plaquetas/fisiologia , Temperatura Alta/efeitos adversos , Ferimentos e Lesões/sangue , Animais , Quimiocina CCL2/sangue , Modelos Animais de Doenças , Inflamação/sangue , Camundongos , Camundongos Endogâmicos C57BL , Contagem de Plaquetas , Taxa de Sobrevida , Fator de Crescimento Transformador beta/sangue , Fator de Necrose Tumoral alfa/análise , Ferimentos e Lesões/imunologia , Ferimentos e Lesões/mortalidade
13.
Physiol Genomics ; 24(3): 298-309, 2006 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-16478828

RESUMO

The aim of this study was to compare gene expression profiles of leukocytes from blood (white blood cells; WBCs) and spleen harvested at an early time point after injury or sham injury in mice subjected to trauma/hemorrhage, burn injury, or lipopolysaccharide (LPS) infusion at three experimental sites. Groups of injured or LPS-infused animals and sham controls were killed at 2 h after injury and resuscitation, blood and spleen were harvested, and leukocyte populations were recovered after erythrocyte lysis. RNA was extracted from postlysis leukocyte populations. Complementary RNA was synthesized from each RNA sample and hybridized to microarrays. A large number (500-1,400) of genes were differentially expressed at the 2-h time point in injured or LPS-infused vs. sham animals. Thirteen of the differentially expressed genes in blood, and 46 in the spleen, were upregulated or downregulated in common among all three animal models and may represent a common, early transcriptional response to systemic inflammation from a variety of causes. The majority of these genes could be assigned to pathways involved in the immune response and cell death. The up- or downregulation of a cohort of 23 of these genes was validated by RT-PCR. This large-scale microarray analysis shows that, at the 2-h time point, there is marked alteration in leukocyte gene expression in three animal models of injury and inflammation. Although there is some commonality among the models, the majority of the differentially expressed genes appear to be uniquely associated with the type of injury and/or the inflammatory stimulus.


Assuntos
Expressão Gênica , Inflamação/genética , Leucócitos/metabolismo , Ferimentos e Lesões/sangue , Animais , Perfilação da Expressão Gênica , Inflamação/sangue , Inflamação/metabolismo , Leucócitos/imunologia , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/sangue , Lipopolissacarídeos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Análise em Microsséries , RNA/análise , RNA/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Baço/metabolismo , Ferimentos e Lesões/complicações , Ferimentos e Lesões/imunologia
14.
J Immunol ; 176(1): 225-36, 2006 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-16365414

RESUMO

CD4+CD25+ regulatory T cells (Tregs) play a critical role in suppressing the development of autoimmune disease, in controlling potentially harmful inflammatory responses, and in maintaining immune homeostasis. Because severe injury triggers both excessive inflammation and suppressed adaptive immunity, we wished to test whether injury could influence Treg activity. Using a mouse burn injury model, we demonstrate that injury significantly enhances Treg function. This increase in Treg activity is apparent at 7 days after injury and is restricted to lymph node CD4+CD25+ T cells draining the injury site. Moreover, we show that this injury-induced increase in Treg activity is cell-contact dependent and is mediated in part by increased cell surface TGF-beta1 expression. To test the in vivo significance of these findings, mice were depleted of CD4+CD25+ T cells before sham or burn injury and then were immunized to follow the development of T cell-dependent Ag-specific immune reactivity. We observed that injured mice, which normally demonstrate suppressed Th1-type immunity, showed normal Th1 responses when depleted of CD4+CD25+ T cells. Taken together, these observations suggest that injury can induce or amplify CD4+CD25+ Treg function and that CD4+CD25+ T cells contribute to the development of postinjury immune suppression.


Assuntos
Queimaduras/imunologia , Linfonodos/imunologia , Linfócitos T Reguladores/imunologia , Animais , Antígenos CD4/imunologia , Antígenos CD4/metabolismo , Comunicação Celular/imunologia , Proliferação de Células , Citocinas/biossíntese , Citometria de Fluxo , Imunofenotipagem , Depleção Linfocítica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Receptores de Interleucina-2/imunologia , Receptores de Interleucina-2/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Crescimento Transformador beta/imunologia , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta1
15.
J Leukoc Biol ; 78(2): 565-73, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15857937

RESUMO

Severe injury primes the innate-immune system for increased Toll-like receptor 4 (TLR4)-induced proinflammatory cytokine production by macrophages. In this study, we examined changes in TLR4 signaling pathways in splenic macrophages from burn-injured or sham mice to determine the molecular mechanism(s) responsible for the increased TLR4 responsiveness. Using flow cytometry and specific antibodies, we first looked for injury-induced changes in the expression levels of several TLR-associated signaling molecules. We found similar levels of myeloid differentiation primary-response protein 88 (MyD88) and interleukin-1 receptor-associated kinase-M (IRAK-M) and somewhat lower levels of total p38, extracellular signal-regulated kinase (ERK), and stress-activated protein kinase (SAPK)/c-jun N-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs) in burn compared with sham macrophages. However, with the use of antibodies specific for the phosphorylated (activated) forms of the three MAPKs, we found that macrophages from burn mice showed a twofold increase in purified lipopolysaccharide (LPS)-stimulated p38 activation as compared with cells from sham mice on days 1 and 7 post-injury, whereas ERK and SAPK/JNK activation was increased by burn injury only on day 1. Using the specific p38 inhibitor (SB203580), we confirmed that the increase in tumor necrosis factor alpha production by LPS-stimulated burn macrophages requires p38 activation. Although we demonstrated that injury increases macrophage TLR4 mRNA expression and intracellular expression of TLR4-myeloid differentiation protein-2 (MD-2) protein, macrophage cell-surface expression of TLR4-MD-2 was not changed by burn injury. Our results suggest that the injury-induced increase in TLR4 reactivity is mediated, at least in part, by enhanced activation of the p38 signaling pathway.


Assuntos
Queimaduras/metabolismo , Ativação Enzimática , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Macrófagos/metabolismo , Glicoproteínas de Membrana/biossíntese , Receptores de Superfície Celular/biossíntese , Transdução de Sinais , Animais , Queimaduras/patologia , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Regulação da Expressão Gênica/efeitos dos fármacos , Imidazóis/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos/patologia , Masculino , Camundongos , Proteína MyoD/metabolismo , Proteínas Quinases/metabolismo , Piridinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Baço/metabolismo , Baço/patologia , Receptor 4 Toll-Like , Receptores Toll-Like
16.
J Immunol ; 174(5): 2957-63, 2005 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-15728508

RESUMO

Major injury initiates a systemic inflammatory response that can be detrimental to the host. We have recently reported that burn injury primes innate immune cells for a progressive increase in TLR4 and TLR2 agonist-induced proinflammatory cytokine production and that this inflammatory phenotype is exaggerated in adaptive immune system-deficient (Rag1(-/-)) mice. The present study uses a series of adoptive transfer experiments to determine which adaptive immune cell type(s) has the capacity to control innate inflammatory responses after injury. We first compared the relative changes in TLR4- and TLR2-induced TNF-alpha, IL-1beta, and IL-6 production by spleen cell populations prepared from wild-type (WT), Rag1(-/-), CD4(-/-), or CD8(-/-) mice 7 days after sham or burn injury. Our findings indicated that splenocytes prepared from burn-injured CD8(-/-) mice displayed TLR-induced cytokine production levels similar to those in WT mice. In contrast, spleen cells from burn-injured CD4(-/-) mice produced cytokines at significantly higher levels, equivalent to those in Rag1(-/-) mice. Moreover, reconstitution of Rag1(-/-) or CD4(-/-) mice with WT CD4(+) T cells reduced postinjury cytokine production to WT levels. Additional separation of CD4(+) T cells into CD4(+)CD25(+) and CD4(+)CD25(-) subpopulations before their adoptive transfer into Rag1(-/-) mice showed that CD4(+)CD25(+) T cells were capable of reducing TLR-stimulated cytokine production levels to WT levels, whereas CD4(+)CD25(-) T cells had no regulatory effect. These findings suggest a previously unsuspected role for CD4(+)CD25(+) T regulatory cells in controlling host inflammatory responses after injury.


Assuntos
Queimaduras/imunologia , Queimaduras/patologia , Mediadores da Inflamação/antagonistas & inibidores , Receptores de Interleucina-2/biossíntese , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Transferência Adotiva , Animais , Queimaduras/genética , Queimaduras/microbiologia , Antígenos CD4/genética , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Proteínas de Homeodomínio/genética , Imunidade Inata/genética , Mediadores da Inflamação/agonistas , Mediadores da Inflamação/fisiologia , Interleucina-1/biossíntese , Interleucina-6/biossíntese , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Peptidoglicano/farmacologia , Receptores de Superfície Celular/agonistas , Receptores de Superfície Celular/antagonistas & inibidores , Receptores de Superfície Celular/fisiologia , Baço/citologia , Baço/imunologia , Baço/metabolismo , Linfócitos T Reguladores/transplante , Receptor 2 Toll-Like , Receptor 4 Toll-Like , Fator de Necrose Tumoral alfa/biossíntese
17.
J Leukoc Biol ; 77(1): 16-23, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15496450

RESUMO

Severe injury can initiate an exaggerated systemic inflammatory response and multiple organ failure (MOF) if a subsequent immune stimulus, "second hit", occurs. Using a mouse thermal injury model, we tested whether changes in innate immune cell reactivity following injury can contribute to the development of heightened inflammation and MOF. Using high-purity Escherichia coli lipopolysaccharide (LPS) to selectively stimulate Toll-like receptor 4 (TLR4), we demonstrate augmented interleukin (IL)-1beta, tumor necrosis factor alpha (TNF-alpha), and IL-6 production by 1 day but particularly, at 7 days after injury. The in vivo significance of enhanced TLR4 responsiveness was explored by challenging sham or burn mice with LPS at 1 or 7 days after injury and determining mortality along with in vivo cytokine and chemokine levels. Mortality was high (75%) in LPS-challenged burn but not sham mice at 7 days, although not at 1 day, after injury. Death was associated with leukocyte sequestration in the lungs and livers along with increased proinflammatory cytokine and chemokine levels in these organs. Blocking TNF-alpha activity prevented this mortality, suggesting that excessive TNF-alpha production contributes to this lethal response. These findings demonstrate the potential lethality of excessive TLR4 reactivity after injury and provide an explanation for the exaggerated inflammatory response to a second hit, which can occur following severe injury.


Assuntos
Queimaduras/imunologia , Glicoproteínas de Membrana/metabolismo , Receptores de Superfície Celular/metabolismo , Ferimentos e Lesões/imunologia , Animais , Queimaduras/metabolismo , Queimaduras/patologia , Modelos Animais de Doenças , Interleucina-1/metabolismo , Interleucina-6/metabolismo , Leucócitos/metabolismo , Lipopolissacarídeos/farmacologia , Fígado/lesões , Fígado/metabolismo , Fígado/patologia , Pulmão/metabolismo , Pulmão/patologia , Lesão Pulmonar , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Taxa de Sobrevida , Receptor 4 Toll-Like , Receptores Toll-Like , Fator de Necrose Tumoral alfa/metabolismo , Ferimentos e Lesões/complicações
18.
J Vasc Surg ; 39(6): 1163-70, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15192553

RESUMO

OBJECTIVE: Repair of thoracovisceral aortic aneurysms (TVAA) after previous open repair of an infrarenal abdominal aortic aneurysm (AAA) poses significant challenges. We sought to better characterize such recurrent aneurysms and to evaluate their operative outcome. METHODS: We reviewed the records and radiographs of 49 patients who underwent repair of TVAAs between 1988 and 2002 after previous repair of an AAA. Visceral artery reconstructions were completed with combinations of beveled anastomoses, inclusion patches, and side arm grafts. In 14 patients visceral endarterectomy was required to treat associated occlusive disease. Sixteen patients had cerebrospinal fluid drainage, and 10 patients had distal perfusion during cross-clamping. RESULTS: Patient mean age was 72 years, and 80% were men. Fifty-one percent of patients had symptomatic disease, and average TVAA diameter was 6.2 cm. Mean time between AAA and TVAA repair was 77 months. Twenty-six percent of aneurysms were restricted to the lower visceral aortic segment, 35% extended to the diaphragm, another 35% extended to the distal or middle thoracic aorta, and 4% involved the entire remaining visceral and thoracic aorta. The 30-day operative mortality rate was 4.1% in patients with nonruptured aneurysms and 50% in patients with ruptured aneurysms, for an overall mortality rate of 8.2%. Fifteen patients (30.6%) had major morbidity, including paresis in two patients and dialysis-dependent renal failure in five patients. At late follow-up, three patients required further aortic operations to treat additional aneurysms, and four patients had fatal aortic ruptures. Two-year and 5-year cumulative survival rates were 61% (+/-7.5%) and 37% (+/-7.8%), respectively. At univariate analysis, operative blood loss was the sole significant predictor of major morbidity (P <.023), and rupture (P <.030, P <.0001) and aneurysm extent (P <.0007, P <.0001) correlated with both operative death and long-term survival. Only aneurysm extent (P <.010, relative risk 37.3) remained a significant predictor of long-term survival at multivariate analysis. CONCLUSION: Elective repair of TVAAs after previous AAA repair can be performed with an acceptable level of operative mortality, though with considerable operative morbidity. Limited long-term survival mandates careful patient selection, and the high mortality associated with ruptured TVAA underscores the need for post-AAA surveillance.


Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Aneurisma da Aorta Torácica/etiologia , Aneurisma da Aorta Torácica/cirurgia , Implante de Prótese Vascular , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Reoperação , Vísceras/irrigação sanguínea , Vísceras/cirurgia , Idoso , Idoso de 80 Anos ou mais , Aorta Torácica/patologia , Aorta Torácica/transplante , Aneurisma da Aorta Torácica/mortalidade , Ruptura Aórtica/etiologia , Ruptura Aórtica/mortalidade , Ruptura Aórtica/cirurgia , Boston , Feminino , Artéria Femoral/patologia , Artéria Femoral/transplante , Seguimentos , Humanos , Artéria Ilíaca/patologia , Artéria Ilíaca/transplante , Masculino , Artéria Mesentérica Superior/patologia , Artéria Mesentérica Superior/transplante , Pessoa de Meia-Idade , Análise Multivariada , Complicações Pós-Operatórias/mortalidade , Recidiva , Artéria Renal/patologia , Artéria Renal/transplante , Análise de Sobrevida , Resultado do Tratamento , Vísceras/patologia
19.
J Immunol ; 172(8): 4883-92, 2004 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-15067067

RESUMO

Severe injury induces a temporal shift in immune reactivity that can cause serious complications or even death. We previously reported that mice exposed to bacterial superantigen (SAg) early after injury undergo a strong SAg response with lethal consequences. This study compares the early and late effects of burn injury on SAg reactivity in vivo to establish how injury influences adaptive immune responses. We found that mice challenged with ordinarily sublethal doses of staphylococcal enterotoxin A or staphylococcal enterotoxin B at 1 day after burn injury exhibited high mortality, whereas no mortality occurred at 7 days after injury. This shift in mortality correlated with higher Th2-type cytokines (IL-4 and IL-10) being expressed by CD4(+) and CD8(+) T cells from burn as opposed to sham mice at 7 days after injury. Lymph node cells from burn-injured mice also produced higher levels of Th2-type cytokines at 7 days after injury. The results of cell-mixing studies using CD4(+) and CD8(+) T cells mixed with APCs from sham or burn mice suggested that changes in both T cells and APCs are involved in the altered SAg response. Finally, the biological significance of altered SAg reactivity following injury was shown by demonstrating that blocking IL-10 activity in vivo caused higher SAg-induced mortality at 7 days after injury. These findings support the idea that injury promotes a Th2-type shift in adaptive immune reactivity. Although prior studies link this counterinflammatory-type response to lowered resistance to infection, the present results suggest it may sometimes benefit the injured host.


Assuntos
Queimaduras/imunologia , Queimaduras/mortalidade , Superantígenos/administração & dosagem , Subpopulações de Linfócitos T/imunologia , Animais , Anticorpos Bloqueadores/administração & dosagem , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/metabolismo , Queimaduras/complicações , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Citocinas/biossíntese , Suscetibilidade a Doenças , Enterotoxinas/administração & dosagem , Enterotoxinas/imunologia , Imunofenotipagem , Injeções Intraperitoneais , Interleucina-10/antagonistas & inibidores , Interleucina-10/imunologia , Linfonodos/imunologia , Linfonodos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Choque Traumático/imunologia , Baço/imunologia , Baço/metabolismo , Staphylococcus aureus/imunologia , Superantígenos/imunologia , Taxa de Sobrevida , Subpopulações de Linfócitos T/metabolismo
20.
J Leukoc Biol ; 75(3): 400-7, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14557385

RESUMO

Although we tend to think that the immune system has evolved to protect the host from invading pathogens and to discriminate between self and nonself, there must also be an element of the immune system that has evolved to control the response to tissue injury. Moreover, these potential immune-regulatory pathways controlling the injury response have likely coevolved in concert with self and nonself discriminatory immune-regulatory networks with a similar level of complexity. From a clinical perspective, severe injury upsets normal immune function and can predispose the injured patient to developing life-threatening infectious complications. This remains a significant health care problem that has driven decades of basic and clinical research aimed at defining the functional effects of injury on the immune system. This review and update on our ongoing research efforts addressing the immunological response to injury will highlight some of the most recent advances in our understanding of the impact that severe injury has on the innate and adaptive immune system focusing on phenotypic changes in innate immune cell responses to Toll-like receptor stimulation.


Assuntos
Glicoproteínas de Membrana/imunologia , Receptores de Superfície Celular/imunologia , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Ferimentos e Lesões/imunologia , Animais , Humanos , Sistema Imunitário/fisiologia , Glicoproteínas de Membrana/metabolismo , Receptores de Superfície Celular/metabolismo , Sepse/imunologia , Sepse/patologia , Síndrome de Resposta Inflamatória Sistêmica/patologia , Receptores Toll-Like , Ferimentos e Lesões/patologia
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