thromboxane-b2 and Pseudomonas-Infections

To examine the activity of myeloperoxidase (MPO) and the concentrations of the proinflammatory metabolites of arachidonic acid (AA) in ocular tissue of mice that are either capable or incapable of restoring corneal clarity during an intraocular Pseudomonas aeruginosa infection.. For a period of 11 days after infection, whole eyes were enucleated and homogenized in buffer from mice given only an initial infection as well as from mice given a subsequent infection in the previously uninfected eye either 4 or 8 weeks after the initial infection. Tissue-free supernatants from the ocular homogenates were used for the determination of MPO activity by quantitating the conversion of specific substrate by spectrophotometric methods and for the quantitation of AA metabolites by ELISA:. Overall, animals reinfected at 4 and 8 weeks had a lower inflammatory response when compared to the mice given only the initial infection. The lowest levels of LTB4 and MPO activity, indicators of PMN involvement, were observed in the the 8-week reinfected mice, which restored corneal clarity in an enhanced manner.. These results suggest that induced ocular PMN responses may play a role, in part, in the inflammatory response leading to the tissue destruction observed during ocular P. aeruginosa infection.

Topics: Animals; Arachidonic Acid; Cornea; Dinoprostone; Enzyme-Linked Immunosorbent Assay; Eye Infections, Bacterial; Female; Keratitis; Leukocyte Count; Leukotriene B4; Mice; Mice, Inbred C57BL; Neutrophils; Peroxidase; Pseudomonas Infections; Thromboxane B2

In order to characterize the inflammatory response to corneal infection by Pseudomonas aeruginosa, ocular cytokine and arachidonic acid metabolite levels were determined in the C57BL/6J strain of mice. The effects of topical anti-inflammatory drugs on the ability of the mice to clear viable P. aeruginosa from the eyes during the 12 day infection period was also examined. Ocular IL-1 alpha, IL-6, and TNF-alpha were detected over an 11 day time period. Little or no bacteria, as determined by quantitative plate counts, was detected after this time period. The kinetics of the cytokine production varied from one another, with an immediate release of peak levels of IL-1 alpha within 24 hours after infection which did not begin to approach baseline until 9 to 11 days after infection. Five to ten-fold lower concentrations of IL-6 and TNF-alpha were detected. IL-6 levels were induced at 24 hours after infection but there was essentially no distinct peak time-point. Peak levels of TNF-alpha were detected at 6 days post-infection. The kinetics of arachidonic acid metabolite release from infected eyes were also examined. Peak levels of PGE2 and TxB2 were observed at 6 days post-infection whereas peak LTB4 levels were determined at 3 days post-infection. Topical treatment of infected eyes with the two anti-inflammatory drugs, prednisolone or quercetin, resulted in higher ocular bacterial levels throughout the infection.

Topics: Animals; Colony Count, Microbial; Cytokines; Dinoprostone; Eye Infections, Bacterial; Keratitis; Mice; Mice, Inbred C57BL; Ophthalmic Solutions; Prednisolone; Pseudomonas aeruginosa; Pseudomonas Infections; Quercetin; Thromboxane B2

Sipid mediators of inflammation have been implicated in the pathogenesis of Pseudomonas aeruginosa (PA) related pulmonary damage in patients with cystic fibrosis. We studied the role of these mediators in a rat model of PA endobronchitis using essential fatty acid deficient (EFAD) animals. Whole blood from EFAD animals produced significantly less leukotriene B4 (LTB4) and hydroxyheptadecatrienoic acid when stimulated ex vivo than did whole blood from control animals (p less than 0.005). Similarly, lung lavage fluid from EFAD animals infected with PA contained less LTB4 and thromboxane B2 (TXB2) than that from control animals. Despite these differences, cellular infiltration of airways in response to PA infection was virtually identical in animals from the regular diet and the EFAD groups. Both EFAD and control animals had a significant increase in white blood cells (WBC) in lung lavage fluid at 1, 3 and 6 days following infection with PA when compared to animals receiving sterile beads. Localized areas of consolidation and nodularity were grossly evident in the lungs of all PA infected animals irrespective of their ability to generate the lipid inflammatory mediators. Microscopic examination of lung sections demonstrated similar changes in all infected animals. We conclude that LTB4 and TXB2 production occurs early in the course of PA pulmonary infection in rats. This early rise in lipid mediators is temporally associated with an influx of WBC into the airways. However, attenuation of eicosanoid production by use of an EFAD diet does not lead to a reduction in the inflammatory response to PA infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bronchoalveolar Lavage Fluid; Dietary Fats, Unsaturated; Eicosanoids; Fatty Acids, Essential; Fatty Acids, Unsaturated; Inflammation; Leukotriene B4; Male; Pneumonia; Pseudomonas Infections; Rats; Rats, Inbred Strains; Thromboxane B2

Tumor necrosis factor (TNF) is implicated in the pathophysiology of gram-negative sepsis. This study examined physiologic and biochemical effects of pretreatment with an anti-TNF alpha monoclonal antibody immediately before the onset of sepsis. Three groups of anesthetized ventilated pigs were studied for 300 minutes. Groups 1 (n = 12) and 2 (n = 6) received a 1-hour infusion of live Pseudomonas aeruginosa. Group 2 was pretreated with anti-TNF alpha monoclonal antibody (15 mg/kg). Group 3 (n = 8) received intravenous sterile saline. Group 1 exhibited a significant rise in plasma TNF activity, which was abolished in group 2. Cardiac index was reduced in both groups 1 and 2 in the first hour but recovered in group 2 (3.3 +/- 0.4 l/min per square meter at 300 minutes in group 2 vs 1.3 +/- 0.2 L/min per square meter in group 1). Metabolic acidosis was attenuated (arterial pH, 7.39 +/- 0.01 in group 2 vs 7.16 +/- 0.03 at 300 minutes in group 1). Increased extravascular lung water was also attenuated (5.9 +/- 0.7 in group 2 vs 13.2 +/- 1.5 mL/kg at 300 minutes in group 1). However, pulmonary hypertension and hypoxemia, which are known cyclooxygenase effects, were not affected. In the early phase of the study, plasma thromboxane B2 levels were elevated in both groups 1 and 2. We conclude that anti-TNF alpha monoclonal antibody offered significant protection against the effects of sepsis, but that other mediators may be responsible for the early changes seen in this model.

Topics: Animals; Antibodies, Monoclonal; Bacteremia; Extravascular Lung Water; Hemodynamics; Lung; Pseudomonas Infections; Shock, Septic; Swine; Thromboxane B2; Tumor Necrosis Factor-alpha

Since fatty acids influence prostaglandin synthesis, and since both fatty acids and prostaglandins modulate immune function, we investigated the hypothesis that manipulation of dietary fats would affect survival after infection in a murine burn model. Mice were fed for 2 to 3 weeks with diets containing different types and amounts of fat. They were then subjected to a 20% flame burn and infected with Pseudomonas aeruginosa. Survival in the group fed 40% of total calories as fish oil had significantly higher mortality than those fed safflower oil. This difference was not noted at lower fat levels. Similar groups of animals were sacrificed the day after injection. Splenic macrophage production of PGE2 was significantly lower in the fish-oil group, but production of LTB4 and TXB2 were not affected. In vitro tests of T- and B-cell function were not different amongst groups. We conclude that manipulation of dietary fats can alter outcome in this murine model of infection after thermal injury.

Topics: Animals; Burns; Dietary Fats, Unsaturated; Dinitrofluorobenzene; Dinoprostone; Fatty Acids, Unsaturated; Female; Hemolytic Plaque Technique; Leukotriene B4; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Pseudomonas Infections; Thromboxane B2

Chronic pulmonary infection/colonization caused by Pseudomonas aeruginosa accounts for much of the morbidity and mortality in cystic fibrosis (CF). The effect of chronic pulmonary P. aeruginosa infection on the pulmonary circulation has not been studied. Therefore, we investigated the effect of chronic P. aeruginosa infection on pulmonary hemodynamics in a rat model. Two groups of rats were inoculated with either agar beads containing 1.0 x 10(4) colony-forming units of P. aeruginosa (infected) or an equal volume of sterile beads alone (control). In vivo, pulmonary vasoreactivity measured as the percent change in total pulmonary resistance during hypoxia was decreased at 1 wk (22 +/- 7% versus 57 +/- 3%), 2 wk (29 +/- 5% versus 73 +/- 17%), 3 wk (41 +/- 8% versus 77 +/- 14%), and 6 to 9 wk (23 +/- 10 versus 53 +/- 7; p less than 0.05 all time points; mean +/- SEM) postinoculation in infected animals when compared with that in time-matched control animals. At 6 to 9 wk postinoculation, pulmonary artery pressure was significantly elevated in infected rats (25.8 +/- 1.6 versus 21.0 +/- 1.0 mm Hg; p less than 0.05) when compared with that in control animals. Histopathologic findings were characterized by bronchiectasis as well as by chronic bronchial, parenchymal, and perivascular inflammation at all time points in infected animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Lung; Male; Pneumonia; Pseudomonas Infections; Pulmonary Circulation; Pulmonary Wedge Pressure; Rats; Rats, Inbred Strains; SRS-A; Thromboxane B2

Acute bilateral Pseudomonas aeruginosa pneumonia was induced in 10 anesthetized dogs, after which five dogs received intravenous indomethacin (2 mg/kg) (indomethacin group), whereas five others were infused with saline (2 ml/kg) (control group). Plasma levels of 6-ketoprostaglandin F1 alpha(6-keto-PGF1 alpha) and thromboxane B2 (TxB2), stable metabolites of prostacyclin (PGI2) and thromboxane A2 (TxA2), respectively, were measured by radioimmunoassay. Although TxB2 levels were not different before and after inoculation in either group, 6-keto-PGF1 alpha levels increased from their base-line value in each animal as pneumonia developed (indomethacin group: less than 100 to 330 +/- 90 pg/ml; control group: less than 100 to 630 +/- 300 pg/ml). Both prostaglandins fell to less than 100 pg/ml in each dog after indomethacin infusion, whereas they remained elevated in the control group after infusion of normal saline. Perfusion of consolidated lung regions (Qp/QT), measured with radioactive microspheres and expressed as a percent of total pulmonary blood flow, was dramatically reduced after indomethacin (35 +/- 3 to 16 +/- 1%) with consequent improvement in pulmonary shunt (Qs/QT: 30 +/- 8 to 18 +/- 6%) and arterial O2 tension (PaO2: 123 +/- 25 to 274 +/- 77 Torr). These parameters remained unchanged or deteriorated further in the control group after infusion of saline. Three additional dogs with Pseudomonas pneumonia were studied in which the indomethacin-induced reduction in Qp/QT was substantially but not completely reversed by intravenous infusion of PGI2.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Carbon Monoxide; Dogs; Epoprostenol; Hemodynamics; Indomethacin; Lung; Pneumonia; Pseudomonas Infections; Pulmonary Gas Exchange; Regional Blood Flow; Thromboxane B2; Vasoconstriction

The effects of ibuprofen (I) and methylprednisolone (M) were studied in the Pseudomonas porcine model of adult respiratory distress syndrome (ARDS). Four groups of animals were anesthetized and ventilated with 0.5 FIO2, 5 cm PEEP, and 20 cc/kg tidal volume: a control group given saline alone; Pseudomonas infusion alone (P); Pseudomonas with ibuprofen (I), 12.5 mg/kg given at 20 and 120 min; and P with methylprednisolone (M), 30 mg/kg given at 20 and 120 min. We compared the alteration in pulmonary hemodynamics with the alteration in the plasma concentration of thromboxane (TxB2) and 6-keto PGF1 alpha in the treated and untreated groups. Hemodynamic parameters measured included the pulmonary (PAP) and systemic (SAP) arterial pressures, cardiac index (C1), thermal-cardiogreen extravascular lung water (EVLW), and PaO2. Albumin Flux was measured by a gamma scintigraphic method (slope index; SI). P produced a dramatic increase in PAP (P less than 0.05) with a progressive increase in EVLW and SI (P less than 0.05) and fall (P less than 0.05) in PaO2, CI, and SAP. The acute pulmonary hypertension was associated with a significant rise in TxB2 and 6-keto PGF1 alpha in the Pseudomonas group. I effectively blocked the elevation of TxB2 and caused a significant but transient improvement in PAP and rise in PaO2. Albumin flux and water leak as measured by SI and EVLW were not affected by ibuprofen. M reduced the elevation of TxB2 and 6-keto PGF1 alpha but failed to block these prostaglandins significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Pressure; Capillary Permeability; Disease Models, Animal; Hemodynamics; Ibuprofen; Methylprednisolone; Pseudomonas Infections; Respiratory Distress Syndrome; Swine; Thromboxane B2

We compared the effects of high frequency jet ventilation (HFV), conventional ventilation (CMV), and spontaneous breathing (SB) on regional pulmonary blood flows (QLLL), standard cardiopulmonary measurements and the serum levels of the first generation metabolites of prostacyclin (6-keto-PGF1 alpha) and thromboxane A2 (TxB2) in established left lower lobe pseudomonas aeruginosa pneumonia in 11 sheep. Gram negative pneumonia resulted in significant increases in alveolar-arterial oxygen gradients [(A-a)DO2] and pulmonary shunt fractions (Qs/Qt), as well as a significant decrease in QLLL during SB. Significant differences in standard haemodynamics, (A-a)DO2, Qs/Qt, and QLLL were not observed when HFV was compared to CMV. However, serum levels of 6-keto-PGF1 alpha were elevated when the animals underwent HFV. We conclude that HFV is a safe and efficient method of oxygenation and ventilation in unilobar gram negative pneumonia and also results in a significant increase in the serum levels of 6-keto-PGF1 alpha when compared to CMV in sheep. The exact significance of the latter finding is the subject of current investigation.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Cardiac Output; Female; Hemodynamics; Pneumonia, Pneumococcal; Pseudomonas Infections; Pulmonary Circulation; Respiration; Respiration, Artificial; Sheep; Thromboxane B2

The effects of ibuprofen (I) were studied in the Pseudomonas (P) porcine ARDS model. Pigs, 14-26 kg (5 in each group), were anesthetized and ventilated with 0.5 FiO2 and 5 cm H2O PEEP. A control (C) group received saline only, a second group was given P, 1 X 10(8) org/ml at 0.3 cc/20 kg/min, and a third group was given P followed by 12.5 mg I at 20 and 120 min. Pulmonary arterial (PAP), wedge (PWP) and systemic arterial pressures, cardiac output (CO), and thermal-cardiogreen extravascular lung water (EVLW), thromboxane (TxB2), 6-keto-PGF1 alpha, PaO2, PaCO2 were determined every 30 min. Albumin flux was measured with scintigraphic determination of lung:heart radioactivity ratios versus time, called slope index (SI). At 3 hr, P produced marked (P less than 0.05) increases in PAP (18 +/- 7 to 37 +/- 2 mm Hg), TxB2 (471 +/- 513 to 9216 +/- 3615 pg/ml), 6-keto-PGF1 alpha, EVLW (6.4 +/- 1.4 to 14.6 +/- 5.7 mg/kg), and SI (0.4 +/- 0.2 to 1.7 +/- 0.5 X 10(-3) U/min) with decreases in PaO2 (214 +/- 47 to 101 +/- 41 torr), CO and SAP. Ibuprofen caused a rapid clearing of TxB2 and 6-keto-PGF1 alpha associated with a transient decrease in PAP; PaO2 was considerably improved compared to P; however, CO, SAP, EVLW, and SI were unaffected. Prostaglandin blockage temporarily ameliorated the pulmonary hypertension and markedly improved oxygenation in this porcine septic ARDS model, but failed to alter increased permeability, confirming other studies that the increased pulmonary shunt in ARDS is not only dependent upon capillary leak.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Blood Pressure; Carbon Dioxide; Cardiac Output; Disease Models, Animal; Ibuprofen; Oxygen; Pseudomonas Infections; Pulmonary Artery; Pulmonary Wedge Pressure; Radioimmunoassay; Respiratory Distress Syndrome; Swine; Thromboxane B2

The pulmonary and systemic response to a full-thickness burn (15% of total body surface area) was determined in 15 adult sheep. Also compared was the effect of wound bacterial content and prostanoid release on this response. Burn wound thromboxane A2, measured as TxB2, and prostacyclin, measured as 6-keto-PGF1 alpha, were measured in burn wound lymph. Animals were monitored for 7 days. On the final day, a full-thickness biopsy specimen of burn tissue was obtained for quantitative bacteriology. Wounds with 10(4) or less organisms per gram of burn tissue were considered colonized, whereas those with 10(5) or more organisms per gram of burn tissue indicated wound infection. Seven sheep had 10(4) or less bacteria and the remaining eight sheep had 10(6) or greater bacteria. We noted a significant mean increase in cardiac index from a baseline of 5 to 6.2 L/min/m2, a decrease in systemic vascular resistance from 16 to 12 mm Hg/L/min, and a mean increase in oxygen consumption from a baseline of 135 to 165 ml/min/m2 during the 7-day study period. There were no differences in these responses between the colonized and the infected wounds. Pulmonary artery pressure increased from a mean baseline of 19 to 24 mm Hg and arterial oxygen tension (PaO2) decreased from a baseline of 90 to 80 mm Hg in the infected wound group, with values remaining at baseline in the colonized wound group. These changes corresponded with an increase in lymph and plasma TxB2 from a baseline of 200 to 210 pg/ml to 1000 +/- 250 and 600 +/- 190 pg/ml, respectively. Values in the animals with colonized wounds were not significantly increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Burns; Escherichia coli Infections; Extracellular Space; Hemodynamics; Lung; Lymph; Pseudomonas Infections; Sheep; Thromboxane B2; Time Factors; Wound Infection

In chronic P. aeruginosa infection, lung tissue damage is induced by either the microorganism or the inflammatory response. We investigated, in an animal model, whether a non-steroidal anti-inflammatory drug, ibuprofen, reduced lung inflammation produced by P. aeruginosa. Lung lavages, pulmonary clearance of P. aeruginosa and lung pathology were studied in CD-1 mice injected with sodium ibuprofenate. A single dose of the drug, injected immediately after 30 min exposure to the P. aeruginosa aerosol, decreased the recruitment of granulocytes into airways in a dose-dependent manner. Pretreatment with 2 doses of the drug 18 and 6 h before the P. aeruginosa challenge was even more effective. The kinetics of changes in prostaglandin E2, 6-keto-prostaglandin F1 alpha and thromboxane B2 concentrations in lung lavage fluids after P. aeruginosa aerosol were also modified by ibuprofen. Moreover, ibuprofen treatment did not impair lung clearance of the challenge microorganisms, and the animals had less inflammation of the lungs.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Dinoprostone; Disease Models, Animal; Ibuprofen; Inflammation; Kinetics; Lung; Male; Mice; Neutrophils; Pneumonia; Prostaglandins E; Pseudomonas Infections; Therapeutic Irrigation; Thromboxane B2

Blockade of the arachidonic acid cascade has been shown to improve survival and hemodynamic alterations in animal models of sepsis and acute respiratory failure (ARF). The effects of intravenous ibuprofen, a cyclooxygenase inhibitor, were observed in 20-30 kg pigs with ARF induced by a continuous LD100 infusion of live Pseudomonas aeruginosa (2 X 10(8)/20 kg/min). Cardiopulmonary parameters were monitored in animals intubated, paralyzed, and ventilated at a 250-ml tidal volume and 0.5 FiO2. Pigs were randomly assigned to three groups: Group I received 2 bolus infusions of ibuprofen (12.5 mg/kg) at 20 and 210 min after baseline; Group II had Ps. aeruginosa (2 X 10(8) CFU/20 kg/min) only; Group III received Ps. aeruginosa and 12.5 mg/kg of ibuprofen at 20 and 210 min of ARF. Ibuprofen alone caused no significant changes in cardiorespiratory parameters. With Ps. aeruginosa infusion, significant pulmonary hypertension, hypoxemia, increased intrapulmonary shunt fraction, and systemic hypotension occurred. In the septic animals treated with ibuprofen, oxygenation was improved by a significant decrease in shunt, pulmonary edema, and pulmonary hypertension.

Topics: Acute Disease; Animals; Disease Models, Animal; Hemodynamics; Ibuprofen; Lung; Male; Pseudomonas Infections; Respiratory Insufficiency; Swine; Thromboxane B2