RESUMEN
The microgravity conditions of prolonged spaceflight are known to result in skeletal muscle atrophy that leads to diminished functional performance. To assess if inhibition of the growth factor myostatin has potential to reverse these effects, mice were treated with a myostatin antibody while housed on the International Space Station. Grip strength of ground control mice increased 3.1% compared to baseline values over the 6 weeks of the study, whereas grip strength measured for the first time in space showed flight animals to be -7.8% decreased in strength compared to baseline values. Control mice in space exhibited, compared to ground-based controls, a smaller increase in DEXA-measured muscle mass (+3.9% vs +5.6% respectively) although the difference was not significant. All individual flight limb muscles analyzed (except for the EDL) weighed significantly less than their ground counterparts at the study end (range -4.4% to -28.4%). Treatment with myostatin antibody YN41 was able to prevent many of these space-induced muscle changes. YN41 was able to block the reduction in muscle grip strength caused by spaceflight and was able to significantly increase the weight of all muscles of flight mice (apart from the EDL). Muscles of YN41-treated flight mice weighed as much as muscles from Ground IgG mice, with the exception of the soleus, demonstrating the ability to prevent spaceflight-induced atrophy. Muscle gene expression analysis demonstrated significant effects of microgravity and myostatin inhibition on many genes. Gamt and Actc1 gene expression was modulated by microgravity and YN41 in opposing directions. Myostatin inhibition did not overcome the significant reduction of microgravity on femoral BMD nor did it increase femoral or vertebral BMD in ground control mice. In summary, myostatin inhibition may be an effective countermeasure to detrimental consequences of skeletal muscle under microgravity conditions.
Asunto(s)
Fuerza Muscular/genética , Músculo Esquelético/fisiología , Atrofia Muscular/genética , Miostatina/genética , Actinas/genética , Animales , Extremidades/fisiología , Fémur/fisiología , Expresión Génica/genética , Guanidinoacetato N-Metiltransferasa/genética , Inmunoglobulina G/genética , Ratones , Ratones Endogámicos BALB C , Fuerza Muscular/fisiología , Atrofia Muscular/fisiopatología , Vuelo Espacial/métodos , IngravidezRESUMEN
Diabetic nephropathy (DN) is a primary cause of end-stage renal disease and is becoming more prevalent because of the global rise in type 2 diabetes. A model of DN, the db/db uninephrectomized ( db/db-uni) mouse, is characterized by obesity, as well as compromised renal function. This model also manifests defects in mineral metabolism common in DN, including hyperphosphatemia, which leads to severe endocrine disease. The FGF23 coreceptor, α-Klotho, circulates as a soluble, cleaved form (cKL) and may directly influence phosphate handling. Our study sought to test the effects of cKL on mineral metabolism in db/db-uni mice. Mice were placed into either mild or moderate disease groups on the basis of the albumin-to-creatinine ratio (ACR). Body weights of db/db-uni mice were significantly greater across the study compared with lean controls regardless of disease severity. Adeno-associated cKL administration was associated with increased serum Klotho, intact, bioactive FGF23 (iFGF23), and COOH-terminal fragments of FGF23 ( P < 0.05). Blood urea nitrogen was improved after cKL administration, and cKL corrected hyperphosphatemia in the high- and low-ACR db/db-uni groups. Interestingly, 2 wk after cKL delivery, blood glucose levels were significantly reduced in db/db-uni mice with high ACR ( P < 0.05). Interestingly, several genes associated with stabilizing active iFGF23 were also increased in the osteoblastic UMR-106 cell line with cKL treatment. In summary, delivery of cKL to a model of DN normalized blood phosphate levels regardless of disease severity, supporting the concept that targeting cKL-affected pathways could provide future therapeutic avenues in DN. NEW & NOTEWORTHY In this work, systemic and continuous delivery of the "soluble" or "cleaved" form of the FGF23 coreceptor α-Klotho (cKL) via adeno-associated virus to a rodent model of diabetic nephropathy (DN), the db/db uninephrectomized mouse, normalized blood phosphate levels regardless of disease severity. This work supports the concept that targeting cKL-affected pathways could provide future therapeutic avenues for the severe mineral metabolism defects associated with DN.
Asunto(s)
Nefropatías Diabéticas/sangre , Glucuronidasa/metabolismo , Fosfatos/sangre , Animales , Glucemia/metabolismo , Línea Celular Tumoral , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/metabolismo , Nefropatías Diabéticas/metabolismo , Modelos Animales de Enfermedad , Factor-23 de Crecimiento de Fibroblastos , Factores de Crecimiento de Fibroblastos/metabolismo , Hiperfosfatemia/sangre , Hiperfosfatemia/metabolismo , Proteínas Klotho , Ratones , Osteoblastos/metabolismo , RatasRESUMEN
Progress in research and developing therapeutics to prevent diabetic kidney disease (DKD) is limited by a lack of animal models exhibiting progressive kidney disease. Chronic hypertension, a driving factor of disease progression in human patients, is lacking in most available models of diabetes. We hypothesized that superimposition of hypertension on diabetic mouse models would accelerate DKD. To test this possibility, we induced persistent hypertension in three mouse models of type 1 diabetes and two models of type 2 diabetes by adeno-associated virus delivery of renin (ReninAAV). Compared with LacZAAV-treated counterparts, ReninAAV-treated type 1 diabetic Akita/129 mice exhibited a substantial increase in albumin-to-creatinine ratio (ACR) and serum creatinine level and more severe renal lesions. In type 2 models of diabetes (C57BKLS db/db and BTBR ob/ob mice), compared with LacZAAV, ReninAAV induced significant elevations in ACR and increased the incidence and severity of histopathologic findings, with increased serum creatinine detected only in the ReninAAV-treated db/db mice. The uninephrectomized ReninAAV db/db model was the most progressive model examined and further characterized. In this model, separate treatment of hyperglycemia with rosiglitazone or hypertension with lisinopril partially reduced ACR, consistent with independent contributions of these disorders to renal disease. Microarray analysis and comparison with human DKD showed common pathways affected in human disease and this model. These results identify novel models of progressive DKD that provide researchers with a facile and reliable method to study disease pathogenesis and support the development of therapeutics.
Asunto(s)
Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Nefropatías Diabéticas/etiología , Modelos Animales de Enfermedad , Hipertensión/complicaciones , Renina/genética , Animales , Antihipertensivos/uso terapéutico , Creatinina/sangre , Dependovirus , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Nefropatías Diabéticas/sangre , Nefropatías Diabéticas/patología , Progresión de la Enfermedad , Femenino , Vectores Genéticos , Hipertensión/tratamiento farmacológico , Hipertensión/genética , Hipoglucemiantes/uso terapéutico , Quinasas Janus/metabolismo , Operón Lac/genética , Lisinopril/uso terapéutico , Masculino , Ratones , Nefrectomía , Óxido Nítrico Sintasa de Tipo III/genética , Rosiglitazona/uso terapéutico , Factores de Transcripción STAT/metabolismo , Albúmina Sérica/metabolismo , Índice de Severidad de la Enfermedad , Transducción de SeñalRESUMEN
αKlotho (αKL) regulates mineral metabolism, and diseases associated with αKL deficiency are characterized by hyperphosphatemia and vascular calcification (VC). αKL is expressed as a membrane-bound protein (mKL) and recognized as the coreceptor for fibroblast growth factor-23 (FGF23) and a circulating soluble form (cKL) created by endoproteolytic cleavage of mKL. The functions of cKL with regard to phosphate metabolism are unclear. We tested the ability of cKL to regulate pathways and phenotypes associated with hyperphosphatemia in a mouse model of CKD-mineral bone disorder and αKL-null mice. Stable delivery of adeno-associated virus (AAV) expressing cKL to diabetic endothelial nitric oxide synthase-deficient mice or αKL-null mice reduced serum phosphate levels. Acute injection of recombinant cKL downregulated the renal sodium-phosphate cotransporter Npt2a in αKL-null mice supporting direct actions of cKL in the absence of mKL. αKL-null mice with sustained AAV-cKL expression had a 74%-78% reduction in aorta mineral content and a 72%-77% reduction in mineral volume compared with control-treated counterparts (P<0.01). Treatment of UMR-106 osteoblastic cells with cKL + FGF23 increased the phosphorylation of extracellular signal-regulated kinase 1/2 and induced Fgf23 expression. CRISPR/Cas9-mediated deletion of fibroblast growth factor receptor 1 (FGFR1) or pretreatment with inhibitors of mitogen-activated kinase kinase 1 or FGFR ablated these responses. In summary, sustained cKL treatment reduced hyperphosphatemia in a mouse model of CKD-mineral bone disorder, and it reduced hyperphosphatemia and prevented VC in mice without endogenous αKL. Furthermore, cKL stimulated Fgf23 in an FGFR1-dependent manner in bone cells. Collectively, these findings indicate that cKL has mKL-independent activity and suggest the potential for enhancing cKL activity in diseases of hyperphosphatemia with associated VC.
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Glucuronidasa/uso terapéutico , Hiperfosfatemia/tratamiento farmacológico , Calcificación Vascular/tratamiento farmacológico , Animales , Huesos/metabolismo , Enfermedad Crónica , Nefropatías Diabéticas/complicaciones , Modelos Animales de Enfermedad , Femenino , Factor-23 de Crecimiento de Fibroblastos , Glucuronidasa/administración & dosificación , Glucuronidasa/fisiología , Hiperfosfatemia/etiología , Proteínas Klotho , Masculino , Ratones , Ratones NoqueadosRESUMEN
Skeletal muscle wasting occurs in a great majority of cancer patients with advanced disease and is associated with a poor prognosis and decreased survival. Myostatin functions as a negative regulator of skeletal muscle mass and has recently become a therapeutic target for reducing the loss of skeletal muscle and strength associated with clinical myopathies. We generated neutralizing antibodies to myostatin to test their potential use as therapeutic agents to attenuate the skeletal muscle wasting due to cancer. We show that our neutralizing antimyostatin antibodies significantly increase body weight, skeletal muscle mass, and strength in non-tumor-bearing mice with a concomitant increase in mean myofiber area. The administration of these neutralizing antibodies in two preclinical models of cancer-induced muscle wasting (C26 colon adenocarcinoma and PC3 prostate carcinoma) resulted in a significant attenuation of the loss of muscle mass and strength with no effect on tumor growth. We also show that the skeletal muscle mass- and strength-preserving effect of the antibodies is not affected by the coadministration of gemcitabine, a common chemotherapeutic agent, in both non-tumor-bearing mice and mice bearing C26 tumors. In addition, we show that myostatin neutralization with these antibodies results in the preservation of skeletal muscle mass following reduced caloric intake, a common comorbidity associated with advanced cancer. Our findings support the use of neutralizing antimyostatin antibodies as potential therapeutics for cancer-induced muscle wasting.
Asunto(s)
Anticuerpos Neutralizantes/farmacología , Músculo Esquelético/efectos de los fármacos , Miostatina/inmunología , Neoplasias/tratamiento farmacológico , Síndrome Debilitante/tratamiento farmacológico , Animales , Anticuerpos Neutralizantes/inmunología , Afinidad de Anticuerpos/inmunología , Peso Corporal/efectos de los fármacos , Línea Celular Tumoral , Evaluación Preclínica de Medicamentos , Femenino , Células HEK293 , Humanos , Masculino , Ratones Endogámicos BALB C , Ratones SCID , Fuerza Muscular/efectos de los fármacos , Músculo Esquelético/patología , Músculo Esquelético/fisiopatología , Miofibrillas/efectos de los fármacos , Neoplasias/complicaciones , Neoplasias Experimentales/complicaciones , Neoplasias Experimentales/tratamiento farmacológico , Trasplante Heterólogo , Resultado del Tratamiento , Síndrome Debilitante/etiologíaRESUMEN
The acute phase response (APR) produces marked alterations in lipid and carbohydrate metabolism including decreasing plasma ketone levels. Fibroblast growth factor 21 (FGF21) is a recently discovered hormone that regulates lipid and glucose metabolism and stimulates ketogenesis. Here we demonstrate that lipopolysaccharide (LPS), zymosan, and turpentine, which induce the APR, increase serum FGF21 levels 2-fold. Although LPS, zymosan, and turpentine decrease the hepatic expression of FGF21, they increase FGF21 expression in adipose tissue and muscle, suggesting that extrahepatic tissues account for the increase in serum FGF21. After LPS administration, the characteristic decrease in plasma ketone levels is accentuated in FGF21-/- mice, but this is not due to differences in expression of carnitine palmitoyltransferase 1α or hydroxymethyglutaryl-CoA synthase 2 in liver, because LPS induces similar decreases in the expression of these genes in FGF21-/- and control mice. However, in FGF21-/- mice, the ability of LPS to increase plasma free fatty acid levels is blunted. This failure to increase plasma free fatty acid could contribute to the accentuated decrease in plasma ketone levels because the transport of fatty acids from adipose tissue to liver provides the substrate for ketogenesis. Treatment with exogenous FGF21 reduced the number of animals that die and the rapidity of death after LPS administration in leptin-deficient ob/ob mice and to a lesser extent in control mice. FGF21 also protected from the toxic effects of cecal ligation and puncture-induced sepsis. Thus, FGF21 is a positive APR protein that protects animals from the toxic effects of LPS and sepsis.
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Reacción de Fase Aguda/metabolismo , Factores de Crecimiento de Fibroblastos/metabolismo , Leptina/deficiencia , Sepsis/metabolismo , Células 3T3-L1 , Reacción de Fase Aguda/sangre , Reacción de Fase Aguda/etiología , Animales , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Ácidos Grasos no Esterificados/sangre , Femenino , Factores de Crecimiento de Fibroblastos/sangre , Factores de Crecimiento de Fibroblastos/genética , Estimación de Kaplan-Meier , Cetonas/sangre , Leptina/genética , Lipopolisacáridos/toxicidad , Hígado/efectos de los fármacos , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , PPAR alfa/deficiencia , PPAR alfa/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sepsis/sangre , Sepsis/fisiopatologíaRESUMEN
Chronic kidney disease pathogenesis involves both tubular and vascular injuries. Despite abundant investigations to identify the risk factors, the involvement of chronic endothelial dysfunction in developing nephropathies is insufficiently explored. Previously, soluble thrombomodulin (sTM), a cofactor in the activation of protein C, has been shown to protect endothelial function in models of acute kidney injury. In this study, the role for sTM in treating chronic kidney disease was explored by employing a mouse model of chronic vascular activation using endothelial-specific TNF-α-expressing (tie2-TNF) mice. Analysis of kidneys from these mice after 3 mo showed no apparent phenotype, whereas 6-mo-old mice demonstrated infiltration of CD45-positive leukocytes accompanied by upregulated gene expression of inflammatory chemokines, markers of kidney injury, and albuminuria. Intervention with murine sTM with biweekly subcutaneous injections during this window of disease development between months 3 and 6 prevented the development of kidney pathology. To better understand the mechanisms of these findings, we determined whether sTM could also prevent chronic endothelial cell activation in vitro. Indeed, treatment with sTM normalized increased chemokines, adhesion molecule expression, and reduced transmigration of monocytes in continuously activated TNF-expressing endothelial cells. Our results suggest that vascular inflammation associated with vulnerable endothelium can contribute to loss in renal function as suggested by the tie2-TNF mice, a unique model for studying the role of vascular activation and inflammation in chronic kidney disease. Furthermore, the ability to restore the endothelial balance by exogenous administration of sTM via downregulation of specific adhesion molecules and chemokines suggests a potential for therapeutic intervention in kidney disease associated with chronic inflammation.
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Albuminuria/prevención & control , Inflamación/tratamiento farmacológico , Fallo Renal Crónico/metabolismo , Trombomodulina/uso terapéutico , Albuminuria/tratamiento farmacológico , Albuminuria/genética , Albuminuria/metabolismo , Animales , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Regulación de la Expresión Génica/fisiología , Inflamación/genética , Inflamación/metabolismo , Fallo Renal Crónico/genética , Ratones , Ratones Transgénicos , Proteínas Tirosina Quinasas Receptoras/genética , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptor TIE-2 , Técnicas de Cultivo de Tejidos , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Hazardous site management in the United States includes remediation of contaminated environmental media and restoration of injured natural resources. Site remediation decisions are informed by ecological risk assessment (ERA), whereas restoration and compensation decisions are informed by the natural resource damage assessment (NRDA) process. Despite similarities in many of their data needs and the advantages of more closely linking their analyses, ERA and NRDA have been conducted largely independently of one another. This is the 4th in a series of papers reporting the results of a recent workshop that explored how ERA and NRDA data needs and assessment processes could be more closely linked. Our objective is to evaluate the technical underpinnings of recentmethods used to translate natural resource injuries into ecological service losses and to propose ways to enhance the usefulness of data obtained in ERAs to the NRDA process. Three aspects are addressed: 1) improving the linkage among ERA assessment endpoints and ecological services evaluated in the NRDA process, 2) enhancing ERA data collection and interpretation approaches to improve translation of ERA measurements in damage assessments, and 3) highlighting methods that can be used to aggregate service losses across contaminants and across natural resources. We propose that ERA and NRDA both would benefit by focusing ecological assessment endpoints on the ecosystem services that correspond most directly to restoration and damage compensation decisions, and we encourage development of generic ecosystem service assessment endpoints for application in hazardous site investigations. To facilitate their use in NRDA, ERA measurements should focus on natural resource species that affect the flow of ecosystem services most directly, should encompass levels of biological organization above organisms, and should be made with the use of experimental designs that support description of responses to contaminants as continuous (as opposed to discrete) variables. Application of a data quality objective process, involving input from ERA and NRDA practitioners and site decision makers alike, can facilitate identification of data collection and analysis approaches that will benefit both assessment processes. Because of their demonstrated relationships to a number of important ecosystem services, we recommend that measures of biodiversity be targeted as key measurement endpoints in ERA to support the translation between risk and service losses. Building from case studies of recent successes, suggestions are offered for aggregating service losses at sites involving combinations of chemicals and multiple natural resource groups. Recognizing that ERA and NRDA are conducted for different purposes, we conclude that their values to environmental decision making can be enhanced by more closely linking their data collection and analysis activities.
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Ecosistema , Monitoreo del Ambiente/métodos , Medición de Riesgo/métodos , Toma de Decisiones , EcologíaRESUMEN
The protein C (PC) pathway plays an important role in vascular function, and acquired deficiency during sepsis is associated with increased mortality. We have explored the role of PC suppression in modulating early inflammatory events in a model of polymicrobial sepsis. We show that increased levels of organ damage and dysfunction are associated with decreased levels of endogenous PC. Notably, animals with low PC had correspondingly high levels of pulmonary iNOS expression, which correlated with chemokines KC/Gro and MIP2, previously shown to predict outcome in this model. Treatment with activated protein C (aPC) not only reduced the pathology score, leukocyte infiltration and markers of organ dysfunction, but also suppressed the induction of iNOS, and the chemokine response (including KC/Gro, MIP2, IP-10, RANTES, GCP-2 and lymphotactin), and increased apoA1. aPC treatment also suppressed the induction of VEGF, a marker recently suggested to play a pathophysiological role in sepsis. These data demonstrate a clear link between low protein C and degree of organ damage and dysfunction in sepsis, as well as the early reversal with aPC treatment. Moreover, our data show a direct role of aPC in broadly modulating monocyte and T-cell chemokines following systemic inflammatory response.
Asunto(s)
Anticoagulantes/uso terapéutico , Quimiocinas/metabolismo , Proteína C/fisiología , Proteína C/uso terapéutico , Sepsis/tratamiento farmacológico , Animales , Biomarcadores/sangre , Ciego/cirugía , Modelos Animales de Enfermedad , Inducción Enzimática/efectos de los fármacos , Ligadura , Óxido Nítrico Sintasa de Tipo II/metabolismo , Proteína C/genética , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/uso terapéutico , Sepsis/sangre , Sepsis/etiología , Sepsis/patología , Índice de Severidad de la Enfermedad , Estadística como Asunto , Resultado del TratamientoRESUMEN
The protein C (PC) pathway plays an important role in vascular and immune function, and acquired deficiency during sepsis is associated with increased mortality in both animal models and in clinical studies. However, the association of acquired PC deficiency with the pathophysiology of lung injury is unclear. We hypothesized that low PC induced by sepsis would associate with increased pulmonary injury and that replacement with activated protein C (APC) would reverse the activation of pathways associated with injury. Using a cecal ligation and puncture (CLP) model of polymicrobial sepsis, we examined the role of acquired PC deficiency on acute lung injury assessed by analyzing changes in pulmonary pathology, chemokine response, inducible nitric-oxide synthase (iNOS), and the angiotensin pathway. Acquired PC deficiency was strongly associated with an increase in lung inflammation and drivers of pulmonary injury, including angiotensin (Ang) II, thymus and activation-regulated chemokine, plasminogen activator inhibitor (PAI)-1, and iNOS. In contrast, the protective factor angiotensin-converting enzyme (ACE)-2 was significantly suppressed in animals with acquired PC deficiency. The endothelial protein C receptor, required for the cytoprotective signaling of APC, was significantly increased post-CLP, suggesting a compensatory up-regulation of the signaling receptor. Treatment of septic animals with APC reduced pulmonary pathology, suppressed the macrophage inflammatory protein family chemokine response, iNOS expression, and PAI-1 activity and up-regulated ACE-2 expression with concomitant reduction in AngII peptide. These data demonstrate a clear link between acquired PC deficiency and pulmonary inflammatory response in the rat sepsis model and provide support for the concept of APC as a replacement therapy in acute lung injury associated with acquired PC deficiency.
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Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Peptidil-Dipeptidasa A/efectos de los fármacos , Deficiencia de Proteína C/tratamiento farmacológico , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Sepsis/complicaciones , Síndrome de Respuesta Inflamatoria Sistémica/tratamiento farmacológico , Enzima Convertidora de Angiotensina 2 , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Animales , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas Inflamatorias de Macrófagos/genética , Óxido Nítrico Sintasa de Tipo II/genética , Inhibidor 1 de Activador Plasminogénico/genética , Deficiencia de Proteína C/etiología , RatasRESUMEN
Low levels of protein C (PC) predict outcome as early as 10 h after insult in a rat polymicrobial sepsis model and were associated with suppression of PC mRNA, upstream transcription factor FoxA2, and cofactor hepatocyte nuclear factor 6 (HNF6). Small interfering RNA suppression of FoxA2 in isolated hepatocytes demonstrated regulation of both its cofactor HNF6 and PC. Our data suggest that reduced FoxA2 may be important in the suppression of PC and resulting poor outcome in sepsis.
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Factor Nuclear 3-beta del Hepatocito/fisiología , Proteína C/antagonistas & inhibidores , Proteína C/biosíntesis , Sepsis/metabolismo , Enfermedad Aguda , Animales , Secuencia de Bases , Biomarcadores , Ciego , Modelos Animales de Enfermedad , Femenino , Factor Nuclear 3-beta del Hepatocito/antagonistas & inhibidores , Factor Nuclear 3-beta del Hepatocito/genética , Ligadura , Datos de Secuencia Molecular , Valor Predictivo de las Pruebas , Pronóstico , Proteína C/genética , Proteína C/fisiología , Punciones , ARN Mensajero/antagonistas & inhibidores , ARN Mensajero/biosíntesis , ARN Interferente Pequeño/farmacología , Ratas , Ratas Sprague-Dawley , Sepsis/diagnóstico , Sepsis/mortalidadRESUMEN
Regulatory CD4(+)CD25(+) T cells (Tregs) suppress autoimmune and inflammatory diseases through mechanisms that are only partly understood. Previous studies suggest that Tregs can suppress bacterially triggered intestinal inflammation and respond to LPS through TLRs with enhanced suppressive activity. In this study, we have used murine cecal ligation and puncture as a model of polymicrobial sepsis to explore the effects of adoptive transfer of Tregs on septic outcome. Adoptive transfer of in vitro-stimulated Tregs in both prevention and therapeutic modes significantly improved survival of cecal ligation and puncture mice. Furthermore, the effect was dependent on both the number of Tregs adoptively transferred and the presence of host T cells. Animals that received stimulated Tregs had significantly increased peritoneal mast cells and peritoneal TNF-alpha production. More importantly, adoptive transfer of in vitro-stimulated Tregs significantly improved bacterial clearance, which resulted in improved survival. Our results suggest a novel role for Tregs in sepsis.