RESUMEN
The impact of Pseudomonas aeruginosa biofilm infections in chronic wounds and clinical implication for healing is receiving increased attention. However, the pathophysiology of host/pathogen interplay is not fully understood. By further revealing the mechanisms, necessary new treatment strategies may be identified. Since the background for chronic wounds is diverse, representative animal models are important. We assessed host response and spontaneous wound closure in the relatively resistant C3H/HeN and the susceptible BALB/c mouse strain. Full-thickness burn wounds were inflicted in 108 mice. Pseudomonas aeruginosa biofilm (106 colony forming units) was injected subcutaneously in 72 mice, euthanised day 4, 7 or 10 days post-infection. Wounds were analysed for neutrophil host response markers: S100A8/A9, keratinocyte-derived chemokine and granulocyte-colony stimulating factor. Total peripheral blood leucocyte and polymorphonuclear count were assessed in parallel. Histopathology evaluated wound inflammatory burden. Photoplanimetry described macroscopical wound closure. Stable chronic wound infection was established in all challenged mice. Pseudomonas aeruginosa biofilm suppressed neutrophil host response in wounds. C3H/HeN mice achieved earlier systemic inflammatory control and healed faster than BALB/c mice. Pseudomonas aeruginosa biofilms perturb host defence thereby inducing a steady state of chronic infection which may impair wound healing. These results indicate therapeutic options for immune modulation of biofilm-infected wounds.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Quemaduras por Electricidad/microbiología , Calgranulina A/inmunología , Calgranulina B/inmunología , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/patogenicidad , Infección de Heridas/microbiología , Animales , Quemaduras por Electricidad/inmunología , Quemaduras por Electricidad/patología , Calgranulina A/genética , Calgranulina B/genética , Modelos Animales de Enfermedad , Femenino , Regulación de la Expresión Génica , Factor Estimulante de Colonias de Granulocitos/genética , Factor Estimulante de Colonias de Granulocitos/inmunología , Interacciones Huésped-Patógeno , Interleucina-1beta/genética , Interleucina-1beta/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Neutrófilos/inmunología , Neutrófilos/microbiología , Infecciones por Pseudomonas/inmunología , Infecciones por Pseudomonas/patología , Pseudomonas aeruginosa/fisiología , Especificidad de la Especie , Cicatrización de Heridas/inmunología , Infección de Heridas/inmunología , Infección de Heridas/patologíaRESUMEN
OBJECTIVE: One of the major obstacles in the treatment of severe electrical burns is properly handling the resulting uncontrolled inflammation. Such inflammation often causes secondary injury and necrosis, thus complicating patient outcomes. Vascular endothelial grow factor (VEGF) has emerged as an important mediator for the recruitment of monocytes to the site inflammation. This study was designed to explore the effects and possible mechanism of VEGF on monocyte-endothelial cellular adhesion. To do so, we used a cultured human monocytic cell line (THP-1) that was stimulated with serum derived from rats that had received electrical burns. METHODS: Serum was obtained from rats that had received electrical burns. Both the VEGF and soluble flt-1 (sflt-1) concentrations of the serum were determined by double-antibody sandwich ELISA. The concentrations of VEGF, sflt-1, and TNF-α obtained from the cell-free cultured supernatant of THP-1 cells that had been exposed to the serum were then determined by double-antibody sandwich ELISA. Serum-stimulated THP-1 cells were added to wells with a monolayer of endothelial cells to detect the level of monocyte-endothelial cells adhesion. Finally, the state of phosphorylation of AKT was determined by Western blotting. RESULTS: Both in vivo and in vitro studies showed that compared to controls, the levels of VEGF were significantly increased after electrical burns. This increased was accompanied by a reduction of sflt-1 levels. Furthermore, the serum of rats that had received electrical burns was able to both activate monocytes to secrete TNF-α and enhance monocyte-endothelial cell adhesion. Treatment with the serum also resulted in an up-regulation of the phosphorylation of AKT, but had no effect on the total levels of AKT. Phosphatidylinositide 3-kinases (PI3K) inhibition decreased the number of THP-1 cells that were adhered to endothelial cells. Finally, sequestering VEGF with sflt-1 was able to reduce the effect on monocyte-endothelial cells adhesion by blocking the PI3K signaling pathway. CONCLUSION: Our results indicate that VEGF is implicated in the pathogenesis of inflammation after electrical burns. Inhibition of VEGF activity could attenuate monocyte-endothelial cells adhesion by suppressing the state of phosphorylation of AKT, which is downstream of the PI3K signaling pathway.
Asunto(s)
Quemaduras por Electricidad/inmunología , Células Endoteliales/inmunología , Monocitos/inmunología , Factor A de Crecimiento Endotelial Vascular/inmunología , Receptor 1 de Factores de Crecimiento Endotelial Vascular/inmunología , Animales , Western Blotting , Quemaduras por Electricidad/metabolismo , Adhesión Celular/inmunología , Línea Celular , Células Endoteliales/metabolismo , Ensayo de Inmunoadsorción Enzimática , Humanos , Técnicas In Vitro , Monocitos/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Factor de Necrosis Tumoral alfa/inmunología , Factor de Necrosis Tumoral alfa/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Receptor 1 de Factores de Crecimiento Endotelial Vascular/metabolismoAsunto(s)
Quemaduras por Electricidad/complicaciones , Cardiomiopatía Dilatada/complicaciones , Traumatismos por Electricidad/complicaciones , Disfunción Ventricular/etiología , Quemaduras por Electricidad/inmunología , Traumatismos por Electricidad/inmunología , Humanos , Masculino , Persona de Mediana Edad , Disfunción Ventricular/inmunologíaRESUMEN
BACKGROUND: Unrecognized laparoscopic bowel injury has a delayed and covert presentation. Differences in monocyte migration and apoptosis between laparoscopic and open bowel injury were determined. METHODS: For this study, 24 rabbits were divided into laparoscopic (n = 9) and open surgical (n = 9) bowel injury groups and a control group (n = 6) without bowel injury. Bowel injury was created using monopolar electrocautery. The animals were killed 1 day, 1 week, and 2 weeks after surgery. Monocyte migration assay was performed across a modified Boyden chamber. Apoptosis was assessed by DNA fluorescent stain H-33342. RESULTS: In laparoscopy, monocyte apoptosis was decreased (p < 0.001), and migration was increased (p < 0.05), as compared with the open group. Apoptosis increased over time in both study groups, and was higher than in the control group (p < 0.001). Migration was decreased in both study groups as compared with the control group (p < 0.05) CONCLUSIONS: These results suggest decreased immune system priming with laparoscopic bowel injury, which may contribute to the masking of relevant signs and symptoms of peritonitis.
Asunto(s)
Quemaduras por Electricidad/patología , Electrocoagulación/efectos adversos , Intestinos/lesiones , Complicaciones Intraoperatorias/patología , Laparoscopía , Macrófagos/patología , Monocitos/patología , Animales , Apoptosis , Bencimidazoles/análisis , Quemaduras por Electricidad/etiología , Quemaduras por Electricidad/inmunología , Movimiento Celular/efectos de los fármacos , Células Cultivadas/citología , Células Cultivadas/efectos de los fármacos , Quimiocina CCL2/farmacología , Colorantes Fluorescentes/análisis , Inmunidad Celular , Perforación Intestinal/etiología , Perforación Intestinal/inmunología , Perforación Intestinal/patología , Intestinos/patología , Complicaciones Intraoperatorias/etiología , Complicaciones Intraoperatorias/inmunología , Laparotomía , Macrófagos/efectos de los fármacos , Peritonitis/etiología , Peritonitis/inmunología , Peritonitis/patología , Neumoperitoneo Artificial , Conejos , Distribución AleatoriaRESUMEN
Immunosuppression following thermal injury has been noted in recent years. Both cellular and humoral immune systems have been reported to be affected. The present study aimed to compare the quantitative differences between cutaneous and electrical burn patients in respect to the partition and levels of lymphocyte populations. From March 1997 through February 1998, 15 patients with major thermal injury or high voltage electrical injury were included in this clinical prospective study. Blood samples were collected at three and seven days postburn. The evaluation of lymphocyte populations of patients was performed by SimulTest IMK plus. T cell and B cell populations, activated T cells, natural killer and helper T cell levels were all suppressed in both groups. Suppressor T cell levels were elevated in electrical burn group at both three and seven days. Therefore, CD 4/CD 8 ratios were more suppressed in electrical burn group. In conclusion, lymphocyte populations in electrical burn patients and also contributing factors which play important roles in the development of sepsis in both group need to be investigated further.