Caspase 3 expression and plasma level of Fas ligand as apoptosis biomarkers in inflammatory endotoxemic lung injury.

OBJECTIVE: The objective of this study is to evaluate if the immunohistochemical expression of a pulmonary apoptosis marker and plasma level of Fas ligand (FasL) correlates with the dose- and time-dependent severity of lung injury, induced by the administration of lipo-polysaccharide (LPS) in an endotoxemic rat model. MATERIALS AND METHODS: Our study included 30 male Wistar rats, randomly divided into three groups: one control group (n=6) and two experimental groups (n=12÷group), in whom we induced endotoxemia by intraperitoneal injection of progressively increasing doses of LPS (5, 10 mg÷kg). We measured FasL plasma levels of the rats at different time points and analyzed the relationships with markers of lung injury. To investigate the level of caspase 3-protein expression, the immunohistochemistry of the lung tissue was assessed. RESULTS: The median percentage of caspase 3-stained cells for the 5 mg÷kg LPS dose was 0.36%, for the 10 mg÷kg LPS dose was 0.4% and for the control group was 0.03% (p<0.0001). The elevated expression levels of caspase 3 were consistent with the altered lung morphologies observed (rs=0.88). LPS administration in rats resulted in a significant dose-dependent increase in the levels of plasma FasL (p<0.0001). These levels correlated with markers of lung injury: degree of hypoxemia (rs=-0.42), histological measured lung injury score (rs=0.72), the density of the caspase 3 staining cells in the immunohistochemistry assessment of apoptosis (rs=0.81) and with the plasma RAGE (receptor for advanced glycated end-products) values (rs=0.70). CONCLUSIONS: Apoptosis is increased in edotoxemia induced lung injury and is likely to contribute to alveolar injury.

Factors Favouring the Development of Clostridium Difficile Infection in Critically Ill Patients.

Clostridium difficile, an anaerobic, spore-forming, toxin-forming, gram-positive bacillus present in the bacterial flora of the colon is the principal cause of nosocomial diarrhoea in adults. AIM: Assessment of favouring factors of Clostridium difficile infections as well as the interactions between them, in critically ill hospitalized patients undergoing complex medical and surgical treatments. MATERIAL AND METHODS: A retrospective case-control study involving eighty patients admitted in the Intensive Care Unit (ICU) of the County Clinical Emergency Hospital Tîrgu-Mures was conducted between January and October 2014. Patients aged eighteen years and over, who had undergone complex medical and surgical treatment, were divided into two subgroups. Group 1 included patients who developed diarrhoea but were not diagnosed as having a Clostridium difficile infection (CDI). Group 2 included patients who developed diarrhoea due to CDI as indicated by a positive culture and the expression of exotoxin. The assessed parameters were age, length of stay (LOS), antibiotic spectrum, association with proton pump inhibitors (PPI) or H2-receptor antagonists, immunological status, the presence or lack of gastrointestinal tract surgery. RESULTS: The mean age was 64.6 years with an average LOS of 10 days. Fifty-six percent of patients came to the ICU from internal medicine wards and forty-three percent from surgical wards. 20.5% of them were immunosuppressed. Co-association of ceftriaxone and pantoprazole significantly increased the risk of CDI compared to co-administration of any other antibiotic or pantoprazole (p=0.01). The odds ratio for Pantoprazole together with any antibiotic versus antibiotic therapy alone was significantly higher (p=0.018) with a sevenfold increase in the risk of positive exotoxin increase. CONCLUSIONS: Antibiotic use is associated with "no risk to develop CDI" in the first five days of administration. PPIs associated therapy increased the risk of CDI in first seventy-two hours regardless of the antibiotic type, and contributes to an active expression of CD exotoxin.

Ischemic preconditioning and inflammatory response syndrome after reperfusion injury: an experimental model in diabetic rats.

Quantification of local ischemia and inflammatory response syndrome correlated with histological changes associated with ischemia-reperfusion injury (IRI) after revascularization techniques. We included 12 adult male Wistar rats, aged eight weeks that were randomly divided into two groups. The first group acted as the control and at the second group, we induced diabetes by intraperitoneal streptozotocin administration (60 mg/kg). After eight weeks, the rats were subject to ischemic preconditioning for 10 minutes at three regular intervals. Twenty-four hours post-preconditioning, both groups were subject to ischemia for 20 minutes, followed by 30 minutes of reperfusion. Oxygen extraction was higher in Group 1, the arterio-venous CO2 gradient was higher in the control group, but not significant. The lactate production was higher in Group 1. The second group had a higher Na+ and also a significant difference in K+ values. Receptor for Advanced Glycation End (RAGE) values were higher in the second group but with no significant difference (RAGE1=0.32 ng/mL versus RAGE2=0.40 ng/mL). The muscle samples from the control group displayed significant rhabdomyolysis, damage to the nucleus, while the preconditioned group showed almost normal morphological characteristics. The lungs and kidneys were most damaged in the control group, with damage expressed as thickened alveolar septa, neutrophil infiltrates, eosinophilic precipitates in the proximal convolute tubule. Ischemic preconditioning significantly attenuates the ischemic reperfusion injury.

Time- and dose-dependent severity of lung injury in a rat model of sepsis.

Different animal models of experimental lung injury have been used to investigate mechanisms of lung injury. Lipopolysaccharide (LPS) administration is the most often used approach to model the consequences of bacterial sepsis. We created an endotoxemia rat model, simulating sepsis-related lung injury, in order to quantify the time and dose dependent severity lesions induced by the administration of lipopolysaccharide. Our study included 42 male Wistar rats, randomly divided into four groups: one control group (n=6) and three experimental groups (n=12/group) in whom we induced sepsis by intraperitoneal injection of progressively increasing doses of LPS (3, 5, 10 mg/kg). At six hours, the animals included in the groups with higher doses of LPS developed thrombocytopenia, elevated lactate levels, and liver and renal injury in a dose and time dependent manner. The severity of hypoxemia at six hours correlated with the increasing doses of LPS, with a slight improvement at 24 hours. Lung injury scores became more severe with increased dose and time of exposure to LPS without reaching the level of hyaline membranes formation. We also demonstrated translocation of a protein from the airspaces into plasma (RAGE - receptor for advanced glycation end products). Induction of sepsis using LPS is a known experimental model, but LPS treatment in rats does not cause the severe endothelial and epithelial injury that occurs in humans with acute respiratory distress syndrome (ARDS). In our study, the clinical, laboratory and histopathological findings confirmed sepsis and the damage of the alveolar-capillary membrane in a dose-dependent manner.