Simulated aeromedical evacuation exacerbates burn induced lung injury: targeting mitochondrial DNA for reversal.

BACKGROUND: Aeromedical evacuation of patients with burn trauma is an important transport method in times of peace and war, during which patients are exposed to prolonged periods of hypobaric hypoxia; however, the effects of such exposure on burn injuries, particularly on burn-induced lung injuries, are largely unexplored. This study aimed to determine the effects of hypobaric hypoxia on burn-induced lung injuries and to investigate the underlying mechanism using a rat burn model. METHODS: A total of 40 male Wistar rats were randomly divided into four groups (10 in each group): sham burn (SB) group, burn in normoxia condition (BN) group, burn in hypoxia condition (BH) group, and burn in hypoxia condition with treatment intervention (BHD) group. Rats with 30% total body surface area burns were exposed to hypobaric hypoxia (2000 m altitude simulation) or normoxia conditions for 4 h. Deoxyribonuclease I (DNase I) was administered systemically as a treatment intervention. Systemic inflammatory mediator and mitochondrial deoxyribonucleic acid (mtDNA) levels were determined. A histopathological evaluation was performed and the acute lung injury (ALI) score was determined. Malonaldehyde (MDA) content, myeloperoxidase (MPO) activity, and the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome level were determined in lung tissues. Data among groups were compared using analysis of variance followed by Tukey's test post hoc analysis. RESULTS: Burns resulted in a remarkably higher level of systemic inflammatory cytokines and mtDNA release, which was further heightened by hypobaric hypoxia exposure (P < 0.01). Moreover, hypobaric hypoxia exposure gave rise to increased NLRP3 inflammasome expression, MDA content, and MPO activity in the lung (P < 0.05 or P < 0.01). Burn-induced lung injuries were exacerbated, as shown by the histopathological evaluation and ALI score (P < 0.01). Administration of DNase I markedly reduced mtDNA release and systemic inflammatory cytokine production. Furthermore, the NLRP3 inflammasome level in lung tissues was decreased and burn-induced lung injury was ameliorated (P < 0.01). CONCLUSIONS: Our results suggested that simulated aeromedical evacuation further increased burn-induced mtDNA release and exacerbated burn-induced inflammation and lung injury. DNase I reduced the release of mtDNA, limited mtDNA-induced systemic inflammation, and ameliorated burn-induced ALI. The intervening mtDNA level is thus a potential target to protect from burn-induced lung injury during aeromedical conditions and provides safer air evacuations for severely burned patients.

Lymph node ratio-based staging system for esophageal squamous cell carcinoma.

AIM: To analyze a modified staging system utilizing lymph node ratio (LNR) in patients with esophageal squamous cell carcinoma (ESCC). METHODS: Clinical data of 2011 patients with ESCC who underwent surgical resection alone between January 1995 and June 2010 at the Cancer Hospital of Shantou University Medical College were reviewed. The LNR, or node ratio (Nr) was defined as the ratio of metastatic LNs ompared to the total number of resected LNs. Overall survival between groups was compared with the log-rank test. The cutoff point of LNR was established by grouping patients with 10% increment in Nr, and then combining the neighborhood survival curves using the log-rank test. A new TNrM staging system, was constructed by replacing the American Joint Committee on Cancer (AJCC) N categories with the Nr categories in the new TNM staging system. The time-dependent receiver operating characteristic curves were used to evaluate the predictive performance of the seventh edition AJCC staging system and the TNrM staging system. RESULTS: The median number of resected LNs was 12 (range: 4-44), and 25% and 75% interquartile rangeswere8 and 16. Patients were classified into four Nr categories with distinctive survival differences (Nr0: LNR = 0; Nr1: 0% < LNR ≤ 10%; Nr2: 10% < LNR ≤ 20%; and Nr3: LNR > 20%). From N categories to Nr categories, 557 patients changed their LN stage. The median survival time (MST) for the four Nr categories (Nr0-Nr3) was 155.0 mo, 39.0 mo, 28.0 mo, and 19.0 mo, respectively, and the 5-year overall survival was 61.1%, 41.1%, 33.0%, and 22.9%, respectively (P < 0.001). Overall survival was significantly different for the AJCC N categories when patients were subgrouped into 15 or more vs fewer than 15 examined nodes, except for the N3 category (P = 0.292). However, overall survival was similar when the patients in all four Nr categories were subgrouped into 15 or more vs fewer than 15 nodes. Using the time-dependent receiver operating characteristic, we found that the Nr category and TNrM stage had higher accuracy in predicting survival than the AJCC N category and TNM stage. CONCLUSION: A staging system based on LNR may have better prognostic stratification of patients with ESCC than the current TNM system, especially for those undergoing limited lymphadenectomy.

PTPRO promoter methylation is predictive of poorer outcome for HER2-positive breast cancer: indication for personalized therapy.

BACKGROUND: Protein Tyrosine Phosphatase Receptor-type O (PTPRO) has recently been in the spotlight as a tumor suppressor, whose encoding gene is frequently methylated in cancers. We examined the methylation status of the PTPRO gene promoter in breast cancer and evaluated the correlation between PTPRO promoter methylation and both clinicopathological parameters and prognosis of breast cancer patients. METHODS: Two hundred twenty-one formalin-fixed, paraffin-embedded (FFPE) tumor tissues, 20 FFPE normal adjacent tissues and 24 matched plasma samples, collected from primary breast cancer patients, were assessed for PTPRO gene promoter methylation using methylation-specific PCR. Associations of promoter methylation with clinicopathological parameters were evaluated. Kaplan-Meier survival analysis and Cox proportional hazards models were used to estimate the effect on survival. RESULTS: 175 samples gave identifiable PCR products, of which 130 cases (74.3%) had PTPRO gene promoter methylation. PTPRO methylation correlated with higher histological grade (P = 0.028), but not other clinical parameters. Multivariate analysis indicated that overall survival (OS) was significantly poorer in HER2-positive, but not ER-positive patients with methylated-PTPRO. Methylated-PTPRO was detectable in matched plasma samples and only observed in plasma from patients whose corresponding primary tumors were also methylated. CONCLUSIONS: PTPRO methylation is a common event in the primary breast cancer and can be reliably detected in peripheral blood samples. PTPRO methylation is associated with poor survival only in HER2-positive patients, suggesting use of PTPRO methylation as a prognostic factor for breast cancer and for optimizing individualized therapy for HER2-positive patients.

A novel model of burn-blast combined injury and its phasic changes of blood coagulation in rats.

Burn-blast combined injury has a complex pathological process that may cause adverse complications and difficulties in treatment. This study aims to establish a standard animal model of severe burn-blast combined injury in rats and also to investigate early phasic changes of blood coagulation. By using 54 Wistar rats, distance from explosion source (Hexogen) and size of burned body surface area were determined to induce severe burn-blast combined injury. Thereafter, 256 rats were randomly divided into four groups (n = 64): blast injury group, burn injury group, burn-blast combined injury group, and sham injury group. Gross anatomy and pathological changes in lungs were investigated at 3, 24, 72, and 168 h, respectively. Blood was also collected for analyzing coagulation parameters as prothrombin time, activated partial thromboplastin time, and plasma levels of fibrinogen, D-dimer, antithrombin III, and α2-antiplasmin from 0 to 168 h after injury. Severe burn-blast combined injury was induced by inflicting rats with a moderate blast injury when placing rats 75 cm away from explosion source and a full-thickness burn injury of 25% total body surface area. The rats with burn-blast combined injury had more severe lung injuries when compared with the other three groups. Pathological examination in the BBL group showed diffused alveolar hemorrhage, fluid filling, alveolar atelectasis, rupture and hyperplasia of partial alveolar septum, emphysema-like change, reduced capillary bed, and infiltration of extensive polymorphonuclear cells after injury. The blood of combined injured rats was in a hypercoagulable state within 24 h, shortly restored from 24 to 48 h, and rehypercoagulated from 48 to 72 h after injury. A secondary excessively fibrinolytic function was also found thereafter. The rat model of burn-blast combined injury was successfully established by simulating real explosion characteristics. Rats with burn-blast combined injuries suffered from more severe lung injuries and abnormal coagulation and fibrinolytic function than those induced by a burn injury or a blast injury component. Hence, a time-dependent treatment strategy on coagulation function should be emphasized in clinical therapy of burn-blast combined injury.

Role of neutrophil elastase in lung injury induced by burn-blast combined injury in rats.

OBJECTIVE: Neutrophil elastase (NE) takes part in the pathogenesis of acute lung injury. However, its role in lung injury of burn-blast combined injury is unclear. Our objective was to assess the role of NE, and effect of sivelestat, a specific NE inhibitor, in lung injury induced by burn-blast combined injury in rats. METHODS: One hundred and sixty male Sprague-Dawley rats were randomly subjected to burn-blast combined injury (BB) group, burn-blast combined injury plus sivelestat treatment (S) group or control (C) group. Blood gas, protein concentration and NE activity in bronchoalveolar lavage fluid (BALF), pulmonary myeloperoxidase (MPO) activity, serum concentrations of TNF-α and IL-8, etc. were investigated from 0 h to 7 d post-injury. RESULTS: In BB group, PaO2 decreased, while NE activity in BALF, total protein concentration in BALF, pulmonary MPO activity and W/D ratio, serum concentrations of TNF-α and IL-8 increased with neutrophil infiltration, progressive bleeding and pulmonary oedema. Compared with BB group, sivelestat treatment decreased the NE activity and ameliorated the above indexes. CONCLUSION: Sivelestat, exerts a protective effect in lung injury after burn-blast combined injury through inhibiting NE activity to decrease pulmonary vascular permeability, neutrophil sequestration, and production of TNF-α and IL-8.

[Effects of carbachol on apoptosis of intestinal epithelial cells after gut ischemia/reperfusion in rat].

OBJECTIVE: To investigate the effects of carbachol on apoptosis of intestinal epithelial cells in rats after gut ischemia/reperfusion (I/R). METHODS: A jejunal sac was formed in Wistar rats. The superior mesenteric artery (SMA) was occluded for 45 minutes followed by 240 minutes of reperfusion. Immediately after occlusion of SAM blood flow, either 0.1 mg/kg of carbachol or same amount of 0.9% saline normal was injected into the jejunal sac. Animals were randomized into three groups (each n=40): sham operation, I/R+normal saline injection (I/R model) and I/R+carbachol injection (0.1 mg/kg, Ca). The Pathological changes in gut epithelial cells were assessed by Chiu's scores. The apoptosis index of intestinal epithelial cell was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining. Expressions of caspase-3 and Bcl-2 in intestinal epithelial cells were assayed by immunohistochemistry method. All measurements were done at 0, 30, 60, 120 and 240 minutes after reperfusion. RESULTS: The Pathological injuries were less severe in Ca group than those in I/R model group. Apoptosis index of intestinal epithelial cell and expressions of caspase-3 were significantly decreased, while the expressions of Bcl-2 increased dramatically (all P<0.01) after I/R in Ca group compared with those in I/R model group, especially at 120 minutes after reperfusion. CONCLUSION: Enteral administration of carbachol can inhibit apoptosis of intestinal epithelial cells in rats after gut I/R injury.

[Influence of carbachol on intestinal dysfunction after traumatic or burn injury].

OBJECTIVE: To investigate the influence of enteral administration of carbachol on the intestinal dysfunction of both severely burn patients and rabbits with partial intestinal ischemia/reperfusion (I/R) injury. METHODS: Seventy-five white rabbits were inflicted with I/R injury and randomized into intestinal I/R (I, n=25), carbachol [C, n=25, with 3g/L carbachol (3 mg/kg) injection into duodenum 1 h after SMA occlusion] and sham operation (SO, n=25, with SMA isolation but no occlusion) groups, and 5 other as normal controls. The blood flow of intestinal mucosa was detected before and after SMA occlusion or admission of carbachol. Changes in diamine oxidase (DAO), D-lactate, xylopyranose absorption, blue dextran discharging time were measured at 2, 4, 6, 8, 24, 48, 72 h after SMA occlusion. In addition, eight severe burn patients with TBSA of 84 +/- 12% were enrolled in the study, and carbachol (15 microg/kg) was administered to patients when abdominal distension or bowel sound was lower than 2 times/min, then the number of abdominal distension and bowel sounds per minute were observed. RESULTS: The blood flow in intestinal mucosa of rabbits without SMA occlusion was (102 +/- 5) PU, reduced to (48 +/- 6) PU after SMA occlusion, and increased to (77 +/- 3) PU after injection of carbachol. The plasma DAO activity and D-lactic acid content in I group began to increase 4 hours after SMA occlusion, and they reached the peak 24 hours after SMA occlusion (4.63 +/- 0.27 U/ml, 7.9 +/- 2.4 mg/L) , after that they decreased gradually, but still higher than the normal value (0.89 +/- 0.14 U/ml, 2.0 +/- 1.1 mg/L, P < 0.05). In carbachol group, data showed the same trends as that in intestine I/R group with lower values, while no obvious changes were in sham operation group (P > 0.05). The content of D-lactic decreased dramatically 2 hours after D-lactic administration in both I and C groups, increased 6 hours after SMA occlusion, then decreased gradually, but it in C group was always higher than normal values, and little fluctuation was in sham operation group. There was no blue dextran discharge 2 hours after SMA occlusion. The discharging distance increased 6 hours later, but it was obviously shorter than the normal value 24 hrs after operation (P < 0.05) , then it returned to normal 48 to 72 hrs after operation. In the C group, blue dextran discharge was found immediately after its injection, with obvious increase in the discharging distance to peak value (43 +/- 6 cm) 6 hours after injury, and returning to normal (28 +/- 3 cm) gradually. In severe burned patients, the bowel sounds was (1.6 +/- 1.1) per minutes before carbachol administration, then increased dramatically to (6.9 +/- 1.7) per minutes 10 mins after administration, reached to a higher level 30 minutes after administration (8.3 +/- 2.4 ) times/min, and it maintained to (6.1 +/- 1.3) times/min 1 hour after administration. Abdominal distension was ameliorated 2 hours after carbachol administration, six patients were able to defecate. CONCLUSION: Enteral administration of Carbachol can increase the blood flow of intestine mucosa, help to improve the movement, absorption and barrier functions of intestine, and ameliorate intestinal dysfunction in patients with severe burns.