To investigate the therapeutic effects of granulocyte colony-stimulating factor (G-CSF) on the functional activities of circulating and peritoneal neutrophils during intra-abdominal sepsis.
Placebo, ...controlled study, using a rat model of intra-abdominal sepsis.
Animal research facility.
Male specific pathogen-free Sprague-Dawley rats.
Abdominal sepsis was produced in rats by cecal ligation and puncture. The control animals received a sham operation. G-CSF (subcutaneous injection at 50 microg/kg) or vehicle (100 microL of 5% dextrose) treatment was initiated at 1 hr after cecal ligation and puncture or sham operation and repeated at 12-hr intervals thereafter.
Six hours after cecal ligation and puncture, CD11b/c and CD18 expression on circulating neutrophils was significantly up-regulated when compared with those in the sham operated control animals. Peritoneal neutrophils exhibited a further up-regulation of these adhesion molecules than did the circulating neutrophils. A sustained up-regulation of CD11b/c and CD18 was found in peritoneal neutrophils even at 24 hrs after cecal ligation and puncture. G-CSF treatment increased CD11b/c expression on circulating neutrophils in 6-hr sham-operated rats, but did not further up-regulate CD11b/c or CD18 expression on circulating or peritoneal neutrophils in cecal ligation and puncture rats. Phagocytic activities of circulating neutrophils assessed by uptake of fluorescent latex microspheres were lower in 24-hr cecal ligation and puncture rats when compared with the sham-operated controls. G-CSF treatment prevented this inhibition. Furthermore, G-CSF enhanced the phagocytic activities of peritoneal neutrophils in both 6- and 24-hr cecal ligation and puncture rats when compared with those of the vehicle-treated animals. Spontaneous hydrogen peroxide generation by circulating neutrophils was increased in 6-hr cecal ligation and puncture rats, but not in 24-hr cecal ligation and puncture rats. Peritoneal neutrophils exhibited an inhibition of phorbol myristate acetate-stimulated hydrogen peroxide generation. G-CSF treatment did not up-regulate neutrophil hydrogen peroxide generation.
Circulating and peritoneal neutrophils exhibit marked polymorphism in their functional activities during the host response to abdominal sepsis. G-CSF treatment significantly enhanced the phagocytic function of both circulating and peritoneal neutrophils which may be one mechanism underlying its protective effect in abdominal sepsis.
Translocation of enteric bacteria or their components (or both) has been postulated to play a role in precipitating sepsis or the systemic inflammatory response syndrome. To simulate the effects of ...translocation on pulmonary host defenses, lipopolysaccharide was injected into the portal vein of normal rats that were subsequently challenged by aerosol inoculation with Pseudomonas aeruginosa. Injection of LPS into the portal vein resulted in increased serum tumor necrosis factor (TNF)-α levels and reduction in lung clearance of P. aeruginosa after aerosol challenge. There were corresponding reductions in alveolar neutrophil recruitment, diminished alveolar macrophage phagocytosis and superoxide anion (O-2) production, and diminished lung TNF recovered by bronchoalveolar lavage. Furthermore, prior intravenous injection of recombinant TNF-α reproduced the defective bacterial clearance, the altered recruitment of airspace neutrophils, and the defective alveolar macrophage phagocytosis. Thus, systemic TNF-α is important in altering pulmonary defenses, and this work supports the concept that bacterial translocation may adversely affect host defenses in distant organs.
To investigate the effect of pretreatment with keratinocyte growth factor on acute permeability pulmonary edema.
Prospective, randomized, controlled animal study.
University research laboratory.
...Specific pathogen-free Sprague-Dawley rats.
Acute permeability pulmonary edema was induced with an injection of alpha-naphthylthiourea, and lung leak was assessed in an isolated perfused lung model over 180 mins. Leak was confirmed with wet/dry lung weight ratios, and the alveolar fluid protein concentration was measured after bronchoalveolar lavage. The effect of pretreatment with keratinocyte growth factor (injected intratracheally 48 hrs before the experiment) on alpha-naphthylthiourea-induced pulmonary edema was assessed (keratinocyte growth factor/alpha-naphthylthiourea group). Control groups (Control and keratinocyte growth factor/Control) were also studied. Histopathology was performed for each of the four groups.
The alpha-naphthylthiourea produced an acute permeability pulmonary edema detected by lung leak over the 180-min ex vivo period of monitoring the isolated perfused lung (leak = 8+/-mL; wet/dry weight ratio 14.7+/-2; lavage protein 3.1+/-1 mg/mL). Pretreatment with keratinocyte growth factor significantly attenuated these parameters (leak = 2.3+/-0.4 mL; wet/dry weight ratio 7.1 +/- 0.5; lavage protein 0.28 +/-0.03 mg/mL), which were not significantly different from the control group and the keratinocyte growth factor/control group. Histopathology showed abundant type II pneumocyte hyperplasia in the lungs of animals pretreated with keratinocyte growth factor, and marked pulmonary edema in animals pretreated with alpha-naphthylthiourea. Less edema was apparent in the keratinocyte growth factor/alpha-naphthylthiourea group. All data are expressed as mean +/- SEM.
Pretreatment with keratinocyte growth factor significantly attenuates pulmonary edema induced by alpha-naphthylthiourea. The mechanisms of this protection are likely related to type II pneumocyte hyperplasia, but remain to be specifically elucidated.
The effect of G-CSF pretreatment on experimental acute lung injury was studied in Sprague-Dawley rats receiving one of the following treatments: (1) G-CSF 50 micrograms/kg subcutaneously twice daily ...beginning 2 d prior to being killed; (2) ANTU 50 mg/kg intraperitoneally; (3) ANTU+G-CSF 50, 25, or 12.5 micrograms/kg; (4) HCl 0.6 ml of a 0.1 N solution intratracheally; (5) HCl+G-CSF 50 or 25 micrograms/kg; (6) control solutions. Lung injury was quantified by measurement of lung wet/dry weights, by histopathologic scoring, and by measurement of fluid flux during ex vivo perfusion. G-CSF pretreatment elevated the baseline blood neutrophil counts as much as 6-fold compared with Control, and it increased the numbers of lung neutrophils and caused a mild histologic lung injury, but it did not significantly alter wet/dry weight ratios or fluid flux. ANTU alone and HCl alone caused a moderate histologic lung injury, increased wet/dry weight ratio, and resulted in a small increase in flux. The combination injuries, ANTU+G-CSF and HCl+G-CSF, caused a more severe lung injury manifested by increased wet/dry weight ratios and increase in flux when compared with ANTU alone and HCl alone, respectively. We conclude that pretreatment with G-CSF potentiates ANTU- and HCl-induced lung injury in non-neutropenic rats. The potential for G-CSF to aggravate acute lung injury in patients remains speculative.
The present study was undertaken to investigate the effects of adrenomedullin (ADM), a newly discovered peptide in normal human plasma, in the pulmonary and systemic vascular bed of the intact cat. ...Because pulmonary blood flow and left atrial pressure were held constant, changes in lobar arterial pressure directly reflected changes in pulmonary vascular resistance. Under conditions of resting (low) pulmonary vasomotor tone, intralobar arterial bolus injections of ADM-(1-52) and two truncated ADM sequences, ADM-(13-52) and ADM-(1-12), had little effect on baseline lobar arterial pressure. In contrast, when pulmonary vasomotor tone was actively increased by intralobar arterial infusion of U-46619, intralobar arterial bolus injections of ADM-(1-52) (10-3,000 ng) and ADM-(13-52) (10-3,000 ng) decreased lobar arterial pressure in a dose-dependent manner, whereas only the highest doses of ADM-(1-52) and ADM-(13-52) (1,000-3,000 ng) mildly decreased systemic arterial pressure. Under the same experimental conditions, injections of ADM-(1-12) had no effect on lobar arterial and systemic arterial pressures. The present data suggest that ADM-(13-52) or a similar ADM fragment is responsible for the marked pulmonary vasodilator activity of ADM-(1-52) in vivo.
We investigated the effect of alcohol (ethanol) on the ability of the alveolar macrophage to produce tumor necrosis factor-alpha (TNF-alpha), superoxide anion (O2-), and nitric oxide (NO)--three ...critical components of pulmonary host defense. Male rats were treated with alcohol either acutely (priming dose 175 mg/100 g of body weight, followed by a 7-hr continuous intravenous infusion of 30 mg/100 g of body weight/hr) or chronically (12-14 weeks of feeding ethanol in a liquid diet). Three hours before sacrifice, the rats received an intravenous injection of saline or lipopolysaccharide (LPS; Escherichia coli, 026:B6, 100 micrograms/100 g of body weight). Alveolar macrophages (AMs) were then isolated by bronchoalveolar lavage and assessed for their in vitro capacity to produce TNF-alpha, O2-, and NO spontaneously and in response to different stimuli. Acute alcohol administration suppressed in vitro LPS-stimulated AM TNF-alpha secretion by 52%. AMs from both pair-and alcohol-fed rats secreted TNF-alpha spontaneously in culture. However, the AMs from chronic alcohol-fed group secreted 42-53% less TNF-alpha spontaneously and in response to LPS, interferon-gamma (IFN-gamma) or IFN-gamma + LPS compared with the AMs from pair-fed group. Systemic LPS treatment inhibited in vitro LPS-stimulated AM TNF-alpha secretion (50%) only in the control rats. Acute alcohol administration enhanced significantly in vitro phorbol 12-myristate 13-acetate (PMA)- and opsonized zymosan (OPZ)-induced AM O2- secretion (4-and 1.8-fold, respectively). Systemic LPS treatment primed the AMs from control rats to secrete 83% more O2- in response to PMA but not OPZ; however, in the acute alcohol-treated group, it suppressed both PMA (54%)- and OPZ (66%)-induced AM O2- release (loss of priming effect of LPS). Chronic alcohol feeding suppressed PMA-induced AM O2- secretion (40%) without affecting the OPZ-induced release. Although systemic LPS treatment had no significant effect on PMA or OPZ-induced AM O2- secretion in the pair-fed group, it enhanced the PMA-stimulated AM O2- release (88%) in the alcohol-fed group. AMs recovered from control or acute alcohol-treated rats did not secrete NO spontaneously in vitro. However, AMs from both pair and chronic alcohol-fed rats secreted NO spontaneously with AMs from chronic alcohol-fed group secreting 34% less. Both acute and chronic alcohol treatment inhibited AM NO secretion in response to IFN-gamma, LPS, and IFN-gamma + LPS significantly. Systemic LPS had no effect on AM NO production in response to different in vitro stimuli in any of the treatment groups. These data suggest that (1) both acute and chronic alcohol administration to rats inhibit AM TNF-alpha and NO secretion; (2) acute and chronic alcohol treatment have differential effects on AM O2- secretion; and (3) alcohol-induced alteration in AM TNF-alpha, O2-, and NO secretion may in part explain the increased susceptibility of alcohol-consuming individuals to pulmonary infections.
Endothelin is a newly described polypeptide derived from endothelial cells. The effects of porcine endothelin on the pulmonary vascular bed and systemic vascular bed were investigated in the ...anesthetized, intact-chest cat under conditions of constant pulmonary blood flow and left atrial pressure. Intralobar bolus injections of porcine endothelin (100-1000 ng) produced a mild vasoconstrictor response in the pulmonary vascular bed. The pulmonary vasoconstrictor response to endothelin was not altered when pulmonary vasomotor tone was increased by infusion of U46619. In contrast to this mild pulmonary vasoconstrictor response, endothelin decreased systemic arterial pressure. Moreover, injections of porcine endothelin into the right and left atria produced similar reductions in aortic pressure as well as similar increases in cardiac output and decreases in systemic vascular resistance. The systemic vasodilator response to porcine endothelin was not affected by beta 2-adrenoceptor blockade. The present data suggest that endothelin does not undergo significant first-pass pulmonary metabolism. The pulmonary vasoconstrictor response to bolus injections of porcine endothelin is not altered by changes in pulmonary vasomotor tone. In contrast, endothelin markedly dilated the systemic vascular bed independently of activation of beta 2-adrenoceptors. The present study provides the first report of the activity of endothelin on pulmonary and systemic hemodynamics in vivo. Moreover, the potent vasodilator activity of endothelin in the systemic vascular bed and its weak effect on pulmonary vessels suggest that endothelin may be more important in the regulation of peripheral vasomotor tone than the pulmonary vascular bed.
We hypothesized that continuous, automatic turning utilizing a patient-friendly, low air loss surface would reduce the incidence of early ICU pneumonia in selected groups of critically ill medical ...patients.
Prospective, randomized, controlled clinical trial. Setting: Medical ICU of a large community teaching hospital.
One hundred twenty-four critically ill new admissions to the medical ICU at Charity Hospital in New Orleans.
Patients were prospectively randomized within one of five diagnosis-related groups (DRG)— sepsis (SEPSIS), obstructive airways disease (OAD), metabolic coma, drug overdose, and stroke—to either routine turning on a standard ICU bed or to continuous turning on an oscillating air-flotation bed for a total of five days.
Patients were monitored daily during the treatment period for the development of pneumonia. The incidence of pneumonia during the first five ICU days was 22 percent in patients randomized to the standard ICU bed vs 9 percent for the oscillating bed (p=0.05). This treatment effect was greatest in the SEPSIS DRG (23 percent vs 3 percent, p=0.04). Continuous automatic oscillation did not significantly change the number of days of required mechanical ventilation, ICU stay, hospital stay, or hospital mortality overall or within any of the DRGs.
We conclude that air-supported automated turning during the first five ICU days reduces the incidence of early ICU pneumonia in selected DRGs; however, this form of automated turning does not reduce other measured clinical outcome parameters.
Furosemide and morphine reduce pulmonary edema associated with congestive heart failure. It is uncertain whether furosemide or morphine are direct-acting relaxants of arterial and venous smooth ...muscle. The authors compared the effect of furosemide and morphine on isolated rings of canine pulmonary artery (PA) and vein (PV) and mesenteric, splenic and anterior tibial arteries and their corresponding veins precontracted with norepinephrine or (15S)-hydroxy-11 alpha, 9 alpha-(epoxymethano)prosta-5Z,13E-dienoic acid. Furosemide (10-300 microM) selectively relaxed veins by an endothelium-independent mechanism, with its greatest efficacy on the PV. Morphine (10-1000 microM) relaxed both arteries and veins. The mechanism of relaxation by furosemide and morphine was examined in the PV and PA. Morphine-induced relaxation of the PV and PA was dependent on prostanoid release from endothelium and smooth muscle because it was attenuated in endothelium-rubbed and ibuprofen-treated PV and PA but not in blood vessels treated with inhibitors of nitric oxide system/cyclic GMP system (I-NG-nitroarginine and methylene blue). Furosemide-mediated relaxation of the PV was refractory to each of these interventions. Similarly, furosemide- and morphine-induced relaxation of the PV were unaffected by 4-aminopyridine, tetraethylammonium, glibenclamide, dendrodotoxin and apamin and, thereby, were independent of an action on K+ channels. Reduction of extracellular K+ or Cl- attenuated furosemide-mediated relaxation of, and inhibition of 86Rb+ uptake by, PV even in the presence of ouabain. It was concluded that furosemide relaxes veins by an effect on Na+/K+/Cl- cotransport or chloride-mediated refilling of intracellular calcium stores.
Tumor necrosis factor-α (TNF), a mono kine produced by lipopolysaccharide (LPS)-stimulated macrophages, is an activator of phagocytic functions and may modulate host responses during infection. To ...determine the effects of LPS on TNF activity and the pulmonary inflammatory response in vivo, we challenged rats systemically or intratracheally with LPS. Intravenous LPS significantly increased serum TNF content from nondetectable levels in control specimens to peak levels at 90 min, which declined to baseline by 3 h. In response to intratracheal LPS, levels of TNF both in bronchoalveolar lavage fluid and associated with alveolar macrophages increased significantly from near nondetectable levels in control animals. Increases in TNF levels werec onfined to the LPS-challenged compartment. Intravenous LPS resulted in a decrease in the number of peripheral blood neutrophils and in sequestration of these cells within the pulmonary vasculature. In contrast, intratracheal LPS elicited a marked intraalveolar inflammatory response.
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