Overexpressed miRNA-155 dysregulates intestinal epithelial apical junctional complex in severe acute pancreatitis.

AIM: To investigate whether miRNA-155 (miR-155) dysregulates apical junctional complex (AJC) protein expression in experimental severe acute pancreatitis (SAP). METHODS: Twenty-four male BALB/c mice were randomly assigned to two groups: the SAP group (n = 12) receiving sequential intraperitoneal injection of 50 µg/kg caerulein and 10 mg/kg lipopolysaccharide over 6 h, and the control group (n = 12) receiving intraperitoneal injection of normal saline. Animals were sacrificed 3 h following the last injection for collection of blood samples and pancreas and distal ileal segment specimens. Routine pancreas and intestine histology was used to assess SAP pathology and intestinal epithelial barrier damage. Levels of serum amylase, diamine oxidase (DAO), and tumor necrosis factor (TNF)-α were determined using commercial kits. Total RNA samples were isolated from intestinal epithelial specimens and reversely transcribed into cDNA. miR-155 and RhoA mRNA expression profiles were determined using quantitative real-time polymerase chain reaction. Target genes for miR-155 were predicted using the miRTarBase database, RNA22 and PicTar computational methods. Western blotting was performed to quantitate the protein expression levels of the target gene RhoA, as well as zonula occludens (ZO)-1 and E-cadherin, two AJC component proteins. RESULTS: Intraperitoneal injection of caerulein and lipopolysaccharide successfully induced experimental acute pancreatic damage (SAP vs control, 10.0 ± 2.0 vs 3.2 ± 1.2, P < 0.01) and intestinal epithelial barrier damage (3.2 ± 0.7 vs 1.4 ± 0.7, P < 0.01). Levels of serum amylase (21.6 ± 5.1 U/mL vs 14.3 ± 4.2 U/mL, P < 0.01), DAO (21.4 ± 4.1 mg/mL vs 2.6 ± 0.8 mg/mL, P < 0.01), and TNF-α (61.0 ± 15.1 ng/mL vs 42.9 ± 13.9 ng/mL, P < 0.01) increased significantly in SAP mice compared to those in control mice. miR-155 was significantly overexpressed in SAP intestinal epithelia (1.94 ± 0.50 fold vs 1.03 ± 0.23 fold, P < 0.01), and RhoA gene containing three miR-155-specific binding sites in the three prime untranslated regions was one of the target genes for miR-155. RhoA (22.7 ± 5.8 folds vs 59.6 ± 11.6 folds, P < 0.01), ZO-1 (46 ± 18 folds vs 68 ± 19 folds, P < 0.01), and E-cadherin proteins (48 ± 15 folds vs 77 ± 18 folds, P < 0.01) were underexpressed in SAP intestinal epithelia although RhoA mRNA expression was not significantly changed in SAP (0.97 ± 0.18 folds vs 1.01 ± 0.17 folds, P > 0.05). CONCLUSION: TNF-α-regulated miR-155 overexpression inhibits AJC component protein syntheses of ZO-1, and E-cadherin by downregulating post-transcriptional RhoA expression, and disrupts intestinal epithelial barrier in experimental SAP.

Myocardial infarction following recombinant tissue plasminogen activator treatment for acute ischemic stroke: a dangerous complication.

Thrombolysis with intravenous tissue plasminogen activator (t-PA) is currently an approved therapy for patients with acute ischemic stroke. Acute myocardial infarction (AMI) immediately following t-PA treatment for stroke is a rare but serious complication. A case of acute myocardial infarction (MI) following IV t-PA infusion for acute stroke was observed. This is a 52-year-old male with a known history of hypertension and chest pain, who subsequently developed MI four hours after IV t-PA was administered for acute ischemic stroke. The disruption of intra-cardiac thrombus and subsequent embolization to the coronary arteries may be an important mechanism. In addition, spontaneous recanalization of infarct-related arteries may be associated with greater myocardial salvage and better prognosis.

[The relationship between HIF-1α expression and the early lung fibrosis in rats with acute paraquat poisoning].

OBJECTIVE: To explore the role of hypoxia-inducible factor 1alpha (HIF-1α) in early lung fibrosis of rats with acute paraquat (PQ) poisoning. METHODS: Forty eight healthy SD rats were randomly divided into control group (6 rats) and paraquat poisoning group (42 rats). Control group was exposed to 1 ml normal solution by gastric gavage. The paraquat group was exposed to 1 ml paraquat solution (50 mg/kg) by gastric gavage for 2, 6, 12, 48, 72 and 120 h, respectively. The arterial blood gas analysis (PaO(2)) was detected. The pathological examinations of lung tissues were performed by HE and Mason staining. HIF-1α in lung tissues were measured by immunofluorescence. Western blot assay was used to detect the expression levels of HIF-1α protein in lung tissues. RESULTS: PaO2 of rats exposed to paraquat for 72 h was (62.33 ± 0.22) mm Hg, which was significantly lower than that (96.00 ± 5.20) of control group (P < 0.05). Pathological examination by HE staining indicated that the acute diffuse lesion appeared in the alveolar capillary endothelium, epithelia and interstitial tissues, and there was the inflammatory cell infiltration in the alveolar of rats exposed to paraquat at 2 h after exposure. At 12 h after exposure, the interstitial edema in lung tissues of rats decreased and the alveolar space became narrow. At 120 h after exposure, there were the alveolar structure derangement, abundant cicatrix, more fibroblasts and peripheral inflammation absorption. Pathological examination by Masson staining showed that there was obvious collagen deposition in the alveolar epithelia at 2h after exposure, the increased collagen fibrosis at 24 and 48 h after exposure and the obvious damage of alveolar tissues or much more fibrous connective tissue deposition at 120 h after exposure. The results of western blot and immunofluorescence assays exhibited that the expression levels of HIF-1α in lung tissues at 2, 24 and 48 h after exposure significantly increased, as compared with control group (P < 0.05), but there were no significant differences of HIF-1α expression among sub-groups at different time points after exposure. CONCLUSION: The results of present study shown that there were the pulmonary fibrosis and increased expression of HIF-1α in acute PQ poisoning rats at the early stage, and HIF-1α may be associated with pulmonary fibrosis.

Effects of dynamic ventilatory factors on ventilator-induced lung injury in acute respiratory distress syndrome dogs.

BACKGROUND: Mechanical ventilation is a double-edged sword to acute respiratory distress syndrome (ARDS) including lung injury, and systemic inflammatory response high tidal volumes are thought to increase mortality. The objective of this study is to evaluate the effects of dynamic ventilatory factors on ventilator induced lung injury in a dog model of ARDS induced by hydrochloric acid instillation under volume controlled ventilation and to investigate the relationship between the dynamic factors and ventilator-induced lung injuries (VILI) and to explore its potential mechanisms. METHODS: Thirty-six healthy dogs were randomly divided into a control group and an experimental group. Subjects in the experimental group were then further divided into four groups by different inspiratory stages of flow. Two mL of alveolar fluid was aspirated for detection of IL-8 and TNF-α. Lung tissue specimens were also extracted for total RNA, IL-8 by western blot and observed under an electronic microscope. RESULTS: IL-8 protein expression was significantly higher in group B than in groups A and D. Although the IL-8 protein expression was decreased in group C compared with group B, the difference was not statistically significant. The TNF-α ray degree of group B was significantly higher than that in the other groups (P<0.01), especially in group C (P>0.05). The alveolar volume of subjects in group B was significantly smaller, and cavity infiltration and cell autolysis were marked with a significant thicker alveolar septa, disorder of interval structures, and blurring of collagenous and elastic fiber structures. A large number of necrotic debris tissue was observed in group B. CONCLUSION: Mechanical ventilation with a large tidal volume, a high inspiratory flow and a high ventilation frequency can cause significant damage to lung tissue structure. It can significantly increase the expression of TNF-α and IL-8 as well as their mRNA expression. Furthermore, the results of our study showed that small tidal ventilation significantly reduces the release of pro-inflammatory media. This finding suggests that greater deterioration in lung injury during ARDS is associated with high inspiratory flow and high ventilation rate.

[The study on pro-adrenomedullin as a new biomarker in sepsis prognosis and risk stratification].

OBJECTIVE: To assess the clinical value of pro-adrenomedullin (pro-ADM) in the prognosis and risk stratification in sepsis. METHODS: Fifty-one critically ill patients admitted to the intensive care unit (ICU) were prospectively stratified into four groups according to internationally recognized criteria: systemic inflammatory response syndrome (SIRS, 25 cases), sepsis (12 cases), severe sepsis (9 cases) and septic shock (5 cases). The levels of plasma pro-ADM was determined in every patient using a new sandwich immunoassay, and compared with procalcitonin (PCT), C-reactive protein (CRP) and interleukin-6 (IL-6), and the acute physiology and chronic health evaluation II (APACHE II) score. RESULTS: (1) Median pro-ADM concentration was 0.34 microg/L for SIRS, 2.23 microg/L for sepsis, 4.57 microg/L for severe sepsis and 8.21 microg/L for septic shock. The plasma concentration of pro-ADM exhibited a gradual increase, and the median pro-ADM value was highest in the septic shock group (all P<0.05). (2) Compared with the other biomarkers, in the sepsis, severe sepsis and septic shock groups, the plasma concentration of pro-ADM and APACHE II score in the non-survivors was significantly higher than in the survivors (pro-ADM: 2.01 microg/L vs. 9.75 microg/L, APACHE II score: 23.44 scores vs. 38.21 scores, both P<0.05). (3) By the receiver operating characteristic (ROC) curve plot analysis of pro-ADM in sepsis, the area under the ROC curve for pro-ADM (0.87) in survivors was similar to the area under the ROC curve for PCT (0.81) and APACHE II score (0.81), and was significantly higher than the area under the ROC curve for CRP (0.53) and IL-6 (0.71). CONCLUSION: The measurement of pro-ADM is a new and useful marker in sepsis prognosis and risk stratification.

[Evaluation of mechanical ventilation for patients with acute respiratory distress syndrome as a result of interstitial pneumonia after renal transplantation].

OBJECTIVE: To evaluate the clinical value of mechanical ventilation for patients with acute respiratory distress syndrome(ARDS) as a result of interstitial pneumonia after renal transplantation in the intensive care unit (ICU). METHODS: All the clinical data (totally 16 cases) were collected, including the improvement of hypoxemia before and after mechanical ventilation. RESULTS: Different levels of positive end-expiratory pressure (PEEP) 4-15 cm H2O (1 cm H2O=0.098 kPa) were applied in the patients in whom mechanical ventilation was instituted. The time for different mechanical ventilation was different [1-87 days, (15.4+/-21.1) days] and duration of survival was different [1-1 945 days, (154.4+/-497.1) days]. Only one of them was survived (6.7%), and the others died (93.3%). The causes of death were analyzed. Among the patients who received the mechanical ventilation, 3 patients were alive less than 3 days and their dire ct cause of death was not respiratory (circulation and central). Only one of them did not receive artificial ventilation and the cause of death was hypoxemia. The successful experience for one survivor among the patients who received the ventilator was that hypoxemia was improved by the mechanical ventilation, winning the time for the treatment of the original disease. CONCLUSION: The major value of mechanical ventilation was to correct the hypoxemia in order to win the time to cure the interstitial pneumonia and ARDS. The survival rate was still low for such a group of patients because the pathogenesis was not identified, and therefore the disease could not be controlled, even the mechanical ventilation is instituted in time.