Diffuse Chorangiomatosis as a Cause of Cardiomegaly, Microangiopathic Hemolytic Anemia and Thrombocytopenia in a Newborn.

INTRODUCTION: The hallmark of diffuse chorangiomatosis is capillary dysvasculogenesis, diffusely involving the placenta. It can cause massive placental enlargement and may have adverse fetal effects. CASE REPORT: A 32 weeks gestation male infant was born via cesarean section and had a placenta weighing 900 g. There was diffuse vascular proliferation involving the stem villi and intermediate villi. Short Nucleotide Polymorphism (SNP) microarray analysis of the placenta showed no biparental mosaicism or loss of heterozygosity, ruling out placental mesenchymal dysplasia. The infant also had cardiomegaly, microangiopathic hemolytic anemia and thrombocytopenia which spontaneously improved over time. CONCLUSION: Diffuse chorangiomatosis can be associated with hemolysis, thrombocytopenia and cardiomegaly in the newborn. However, once delivered, these findings can spontaneously resolve over time.

Nebulized Epinephrine Limits Pulmonary Vascular Hyperpermeability to Water and Protein in Ovine With Burn and Smoke Inhalation Injury.

OBJECTIVES: To test the hypothesis that nebulized epinephrine ameliorates pulmonary dysfunction by dual action-bronchodilation (ß2-adrenergic receptor agonism) and attenuation of airway hyperemia (α1-adrenergic receptor agonism) with minimal systemic effects. DESIGN: Randomized, controlled, prospective, and large animal translational studies. SETTING: University large animal ICU. SUBJECTS: Twelve chronically instrumented sheep. INTERVENTIONS: The animals were exposed to 40% total body surface area third degree skin flame burn and 48 breaths of cooled cotton smoke inhalation under deep anesthesia and analgesia. The animals were then placed on a mechanical ventilator, fluid resuscitated, and monitored for 48 hours in a conscious state. After the injury, sheep were randomized into two groups: 1) epinephrine, nebulized with 4 mg of epinephrine every 4 hours starting 1 hour post injury, n = 6; or 2) saline, nebulized with saline in the same manner, n = 6. MEASUREMENTS AND MAIN RESULTS: Treatment with epinephrine had a significant reduction of the pulmonary transvascular fluid flux to water (p < 0.001) and protein (p < 0.05) when compared with saline treatment from 12 to 48 hours and 36 to 48 hours, respectively. Treatment with epinephrine also reduced the systemic accumulation of body fluids (p < 0.001) with a mean of 1,410 ± 560 mL at 48 hours compared with 3,284 ± 422 mL of the saline group. Hemoglobin levels were comparable between the groups. Changes in respiratory system dynamic compliance, mean airway pressure, PaO2/FiO2 ratio, and oxygenation index were also attenuated with epinephrine treatment. No considerable systemic effects were observed with epinephrine treatment. CONCLUSIONS: Nebulized epinephrine should be considered for use in future clinical studies of patients with burns and smoke inhalation injury.

Histological evidence of oxidative stress and premature senescence in preterm premature rupture of the human fetal membranes recapitulated in vitro.

Preterm prelabor rupture of the membranes (pPROM) may lead to preterm births (PTBs). We investigated premature senescence of fetal membranes in women with pPROM and spontaneous PTB with intact membranes (<34 weeks) and the inducibility fetal membrane senescence phenotype by oxidative stress in vitro. IHC was performed for p53, p21, and phospho (p)-p38 mitogen-activated protein kinase (MAPK) as markers of senescence phenotype in pPROM, PTBs, and term births. Term fetal membranes were exposed to cigarette smoke extract to induce oxidative stress. Western blots documented p-p53 and p-p38 MAPK. Transmission electron microscopy assessed cellular morphologic features in clinical and cigarette smoke extract-treated membranes. A total of 80% of pPROM cells and >60% of term cells were positive for all three senescence phenotype markers, and concentrations were higher than in PTBs (P < 0.05). p53 staining was comparable in membranes from PTB and term birth pregnancies, whereas only <30% and <45% of cells were positive for p21 and p38 MAPK, respectively. In vitro cigarette smoke extract exposure increased p-p38 MAPK without any detectable change in p-p53 MAPK. Enlargement of organelles consistent with senescence phenotype was evident in pPROM and term membranes in vivo and after cigarette smoke extract treatment in vitro but was less apparent in PTBs. Histologic and biochemical resemblance of pPROM and term membranes suggests premature senescence of the membranes is a mechanistic feature in pPROM, and this can be phenocopied in an in vitro model.

Non-fecalith-induced appendicitis: etiology, imaging, and pathology.

This study aims to document the imaging and pathology findings in non-fecalith-induced appendicitis. We reviewed the imaging and pathologic findings in 40 patients with histologically proven purulent appendicitis seen over a 2-year period. Findings documented were (1) total appendiceal involvement, (2) predominant appendiceal tip involvement, (3) presence of a fecalith, and (4) presence of lymphoid hyperplasia. There were a total of 40 patients, 28 males and 12 females. The age range was 2-18 years with a mean of 11.5 years. Twenty-two (55 %) patients demonstrated classic purulent appendicitis of the whole appendix, 20 (91 %) of these appendices had a fecalith. Eighteen (45 %) patients demonstrated purulent appendicitis confined to or predominately involving the tip of the appendix, and all 18 (100 %) patients demonstrated marked lymphoid hyperplasia. Only two (11 %) of these appendices had a fecalith. Overall, a fecalith was found in only 55 % of our cases, while 45 % demonstrated no fecalith, but rather marked lymphoid hyperplasia. Lymphoid hyperplasia appeared to be the underlying predisposing cause of purulent appendicitis in these cases.

Human mesenchymal stem cells reduce the severity of acute lung injury in a sheep model of bacterial pneumonia.

BACKGROUND: Human bone marrow-derived mesenchymal stem (stromal) cells (hMSCs) improve survival in mouse models of acute respiratory distress syndrome (ARDS) and reduce pulmonary oedema in a perfused human lung preparation injured with Escherichia coli bacteria. We hypothesised that clinical grade hMSCs would reduce the severity of acute lung injury (ALI) and would be safe in a sheep model of ARDS. METHODS: Adult sheep (30-40 kg) were surgically prepared. After 5 days of recovery, ALI was induced with cotton smoke insufflation, followed by instillation of live Pseudomonas aeruginosa (2.5×10(11) CFU) into both lungs under isoflurane anaesthesia. Following the injury, sheep were ventilated, resuscitated with lactated Ringer's solution and studied for 24 h. The sheep were randomly allocated to receive one of the following treatments intravenously over 1 h in one of the following groups: (1) control, PlasmaLyte A, n=8; (2) lower dose hMSCs, 5×10(6) hMSCs/kg, n=7; and (3) higher-dose hMSCs, 10×10(6) hMSCs/kg, n=4. RESULTS: By 24 h, the PaO2/FiO2 ratio was significantly improved in both hMSC treatment groups compared with the control group (control group: PaO2/FiO2 of 97±15 mm Hg; lower dose: 288±55 mm Hg (p=0.003); higher dose: 327±2 mm Hg (p=0.003)). The median lung water content was lower in the higher-dose hMSC-treated group compared with the control group (higher dose: 5.0 g wet/g dry [IQR 4.9-5.8] vs control: 6.7 g wet/g dry [IQR 6.4-7.5] (p=0.01)). The hMSCs had no adverse effects. CONCLUSIONS: Human MSCs were well tolerated and improved oxygenation and decreased pulmonary oedema in a sheep model of severe ARDS. TRAIL REGISTRATION NUMBER: NCT01775774 for Phase 1. NCT02097641 for Phase 2.

The selective vasopressin type 1a receptor agonist selepressin (FE 202158) blocks vascular leak in ovine severe sepsis*.

OBJECTIVE: To determine if the selective vasopressin type 1a receptor agonist selepressin (FE 202158) is as effective as the mixed vasopressin type 1a receptor/vasopressin V2 receptor agonist vasopressor hormone arginine vasopressin when used as a titrated first-line vasopressor therapy in an ovine model of Pseudomonas aeruginosa pneumonia-induced severe sepsis. DESIGN: Prospective, randomized, controlled laboratory experiment. SETTING: University animal research facility. SUBJECTS: Forty-five chronically instrumented sheep. INTERVENTIONS: Sheep were anesthetized, insufflated with cooled cotton smoke via tracheostomy, and P. aeruginosa were instilled into their airways. They were then placed on assisted ventilation, awakened, and resuscitated with lactated Ringer's solution titrated to maintain hematocrit ± 3% from baseline levels. If, despite fluid management, mean arterial pressure fell by more than 10 mm Hg from baseline level, an additional continuous IV infusion of arginine vasopressin or selepressin was titrated to raise and maintain mean arterial pressure within no less than 10 mm Hg from baseline level. Effects of combination treatment of selepressin with the selective vasopressin V2 receptor agonist desmopressin were similarly investigated. MEASUREMENTS AND MAIN RESULTS: In septic sheep, MAP fell by ~30 mm Hg, systemic vascular resistance index decreased by ~50%, and ~7 L of fluid were retained over 24 hours; this fluid accumulation was partially reduced by arginine vasopressin and almost completely blocked by selepressin; and combined infusion of selepressin and desmopressin increased fluid accumulation to levels similar to arginine vasopressin treatment. CONCLUSIONS: Resuscitation with the selective vasopressin type 1a receptor agonist selepressin blocked vascular leak more effectively than the mixed vasopressin type 1a receptor/vasopressin V2 receptor agonist arginine vasopressin because of its lack of agonist activity at the vasopressin V2 receptor.

Tiotropium bromide suppresses smoke inhalation and burn injury-induced ERK 1/2 and SMAD 2/3 signaling in sheep bronchial submucosal glands.

The effects of tiotropium bromide on ERK 1/2, SMAD 2/3 and NFκB signaling in bronchial submucosal gland (SMG) cells of sheep after smoke inhalation and burn injury (S + B) were studied. We hypothesized that tiotropium would modify intracellular signaling processes within SMG cells after injury. Bronchial tissues were obtained from uninjured (sham, n = 6), S + B injured sheep 48 h after injury (n = 6), and injured sheep nebulized with tiotropium (n = 6). The percentage (mean ± SD) of cells showing nuclear localization of phosphorylated ERK 1/2, pSMAD 2/3, and NFκB (p65) was determined by immunohistochemistry. Nuclear pERK 1/2 staining was increased in injured animals as compared to sham, (66 ± 20 versus 14 ± 9), p = 0.0022, as was nuclear pSMAD, 84 ± 10 versus 20 ± 10, p = 0.0022. There was a significant decrease in pERK 1/2 labeling in the tiotropium group compared to the injured group (31 ± 20 versus 66 ± 20, p = 0.013), and also a decrease in pSMAD labeling, 62 ± 17 versus 84 ± 10, p = 0.04. A significant increase for NFκB (p65) was noted in injured animals as compared to sham (73 ± 16 versus 7 ± 6, p = 0.0022). Tiotropium-treated animals showed decreased p65 labeling as compared to injured (35 ± 17 versus 74 ± 16, p = 0.02). The decrease in nuclear expression of pERK, pSMAD and NFκB molecules in SMG cells with tiotropium treatment is suggestive that their activation after injury is mediated in part through muscarinic receptors.

Maternal tobacco use is associated with increased markers of oxidative stress in the placenta.

OBJECTIVE: We sought to extend our prior observations and histopathologically characterize key metabolic enzymes (CYP1A1) with markers of oxidative damage in the placental sections from smokers. STUDY DESIGN: Placental specimens were collected from term singleton deliveries from smokers (n = 10) and nonsmokers (n = 10) and subjected to a detailed histopathological examination. To quantify the extent of oxidative damage, masked score-graded (0-6) histopathology against 4-hydroxy-2-nonenal (4-HNE) and 8-hydroxydeoxyguanisine (8-OHdG) was performed. Minimal significance (P < .05) was determined with a Fisher's exact and a 2-tailed Student t test as appropriate. RESULTS: We observed a significant increase in the presence of syncytial knots in placentas from smokers (70% vs 10%, P = .02). These gross observations were accompanied by a significant aberrant placental aromatic hydrocarbon metabolism (increased CYP1A1, 4.4 vs 2.1, P = .002) in addition to evidence of oxidative damage (4-HNE 3.4 vs 1.1, P = .00005; 8-OHdG 4.9 vs 3.1, P = .0038). CONCLUSION: We observed a strong association between maternal tobacco use and aberrant placental metabolism, syncytial knot formation, and multiple markers of oxidative damage.

Association between dietary fat content and outcomes in pediatric burn patients.

BACKGROUND: The aim of the study was to compare a low fat/high-carbohydrate diet and a high-fat diet on clinical outcomes by a retrospective cohort study. METHODS: Nine hundred forty-four children with burns ≥ 40% of their total body surface area (TBSA) were divided into two groups: patients receiving Vivonex T.E.N. (low-fat/high-carbohydrate diet; n = 518) and patients receiving milk (high-fat diet; n = 426). Patient demographics, caloric intake, length of hospital stay, and incidence of sepsis, mortality, hepatic steatosis, and organomegaly at autopsy were determined. RESULTS: Demographics and caloric intake were similar in both groups. Patients receiving Vivonex T.E.N. had shorter (intensive care unit) ICU stays (Vivonex T.E.N.: 31 ± 2 d; milk: 47 ± 2 d; P < 0.01), shorter ICU stay per % TBSA burn (Vivonex T.E.N.: 0.51 ± 0.02 d/%; milk: 0.77 ± 0.03 d/%; P < 0.01), lower incidence of sepsis (Vivonex T.E.N.: 11%; milk: 20%; P < 0.01), and lived significantly longer until death than those receiving milk (Vivonex T.E.N.: 20 ± 3 d; milk: 10 ± 2 d; P < 0.01). There was no difference in overall mortality between the two groups (Vivonex T.E.N.:15% versus milk: 13%; P < 0.9). Autopsies revealed decreased hepatic steatosis and decreased enlargement of kidney and spleen in patients receiving Vivonex T.E.N. CONCLUSIONS: The period with a low-fat/high-carbohydrate diet was associated with lower LOS, decreased incidence of organomegaly, infection, and hepatic steatosis post-burn compared with the period when a high-fat diet was used. These associations indicate the benefit of high carbohydrate/low fat nutrition; however, the findings in these time periods can also be likely due to the multifactorial effects of advances in burn care. We believe that these results have some relevance because high fat is associated with poorer outcomes compared with low fat.

Is there a difference in clinical outcomes, inflammation, and hypermetabolism between scald and flame burn?

OBJECTIVE: Severe thermal injury induces inflammatory and hypermetabolic responses that are associated with morbidity and mortality. However, it is not well-documented whether the causes of burns affect inflammation, hypermetabolism, and morbidity. The aim of the present study was to determine whether there is a difference in degree of inflammation, hypermetabolism, endocrine and acute-phase response, and clinical outcome between pediatric patients with scald and flame burns. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Children with burns requiring surgical intervention were enrolled in this cohort study and divided into two groups, scald or flame burn. In a second assignment, we analyzed the study populations in representative subgroups containing individuals with third-degree burns of 40% to 60% total body surface area. We determined clinical outcomes, resting energy expenditures, cytokine profiles, acute-phase proteins, constitutive proteins, and hormone panels. Statistical analysis was evaluated by analysis of variance, Student's t test corrected with the Bonferroni post hoc test, and the propensity score. Statistical significance was set at p < .05. A total of 912 patients were identified. Six hundred seventy-four had a flame burn and 238 had a scald burn. There was a significant difference (p < .05) in burn size (flame, 48% ± 23%; scald, 40% ± 21%), third-degree burn (flame, 39% ± 27%; scald 22% ± 25%), age (flame, 8 ± 5 yrs; scald, 3 ± 3 yrs), and mortality between groups. Propensity analysis confirmed the type of burn as a significant risk factor for morbidity and mortality. Subanalysis conducted in a representative patient group suffering from 40% to 60% burn total body surface area revealed that flame burns lead to significantly increased hypermetabolic, inflammatory, and acute-phase responses when compared to scald burns (p < .05). The frequency of sepsis was 3% in the scald burn group, while it was 14% in the flame group (p < .001). Multiorgan failure occurred in 14% of the scald patients, while it occurred in 17% of flame patients. The mortality in patients suffering from a scald burn was 3% compared to 6% in the flame-burned group (p < .05). CONCLUSION: The type of burn affects hypermetabolism, inflammation, acute-phase responses, and mortality postburn.

Intestinal mitochondrial apoptotic signaling is activated during oxidative stress.

PURPOSE: Reactive oxygen species (ROS) are thought to contribute to the pathogenesis of necrotizing enterocolitis (NEC). Mitochondria as a major source of intracellular ROS and apoptotic signaling during oxidative stress in NEC have not been investigated. We sought to determine: (1) the effects of oxidative stress on intestinal mitochondrial apoptotic signaling, and (2) the role of growth factors in this process. METHODS: We used Swiss-Webster mice pups, and rat intestinal epithelial (RIE)-1, mitochondrial DNA-depleted RIE-1 cell line (RIE-1-ρ°) and human fetal intestinal epithelial cells (FHs74 Int) for our studies. RESULTS: H(2)O(2) induced apoptosis and ROS production. ROS-mediated activation of apoptotic signaling was significantly attenuated with mitochondrial silencing in RIE-1-ρ° cells. Growth factors, especially IGF-1, attenuated this response to H(2)O(2) in intestinal epithelial cells. CONCLUSIONS: Our findings suggest that mitochondria are a major source of intestinal apoptotic signaling during oxidative stress, and modulating mitochondrial apoptotic responses may help ameliorate the effects of NEC.

Molecular biological effects of selective neuronal nitric oxide synthase inhibition in ovine lung injury.

Neuronal nitric oxide synthase is critically involved in the pathogenesis of acute lung injury resulting from combined burn and smoke inhalation injury. We hypothesized that 7-nitroindazole, a selective neuronal nitric oxide synthase inhibitor, blocks central molecular mechanisms involved in the pathophysiology of this double-hit insult. Twenty-five adult ewes were surgically prepared and randomly allocated to 1) an uninjured, untreated sham group (n = 7), 2) an injured control group with no treatment (n = 7), 3) an injury group treated with 7-nitroindazole from 1-h postinjury to the remainder of the 24-h study period (n = 7), or 4) a sham-operated group subjected only to 7-nitroindazole to judge the effects in health. The combination injury was associated with twofold increased activity of neuronal nitric oxide synthase and oxidative/nitrosative stress, as indicated by significant increases in plasma nitrate/nitrite concentrations, 3-nitrotyrosine (an indicator of peroxynitrite formation), and malondialdehyde lung tissue content. The presence of systemic inflammation was evidenced by twofold, sixfold, and threefold increases in poly(ADP-ribose) polymerase, IL-8, and myeloperoxidase lung tissue concentrations, respectively (each P < 0.05 vs. sham). These molecular changes were linked to tissue damage, airway obstruction, and pulmonary shunting with deteriorated gas exchange. 7-Nitroindazole blocked, or at least attenuated, all these pathological changes. Our findings suggest 1) that nitric oxide formation derived from increased neuronal nitric oxide synthase activity represents a pivotal reactive agent in the patho-physiology of combined burn and smoke inhalation injury and 2) that selective neuronal nitric oxide synthase inhibition represents a goal-directed approach to attenuate the degree of injury.

Muscarinic receptor antagonist therapy improves acute pulmonary dysfunction after smoke inhalation injury in sheep.

OBJECTIVES: Inhalation injury contributes to the morbidity and mortality of burn victims. In humans and in an ovine model of combined smoke inhalation and burn injury, bronchospasm and acute airway obstruction contribute to progressive pulmonary insufficiency. This study tests the hypothesis that muscarinic receptor antagonist therapy with tiotropium bromide, an M1 and M3 muscarinic receptor antagonist, will decrease the airway constrictive response and acute bronchial obstruction to improve pulmonary function compared to injured animals without treatment. DESIGN: Randomized, prospective study involving 32 sheep. SETTING: Large-animal intensive care research laboratory. INTERVENTIONS: The study consisted of six groups: a sham group (n=4, instrumented noninjured), a control group (n=6, injured and not treated), and tiotropium bromide-treated groups, including both preinjury and postinjury nebulization protocols. Treatments for these groups included nebulization with 36 µg of tiotropium bromide 1 hr before injury (n=6) and postinjury nebulization protocols of 18 µg (n=6), 36 µg (n=6), and 72 µg (n=4) administered 1 hr after injury. All treated groups received an additional 14.4 µg every 4 hrs for the 24-hr study period. MAIN RESULTS: Pretreatment with tiotropium bromide significantly attenuated the increases in ventilatory pressures, pulmonary dysfunction, and upper airway obstruction that occur after combined smoke inhalation and burn injury. Postinjury treatments with tiotropium bromide were as effective as pretreatment in preventing pulmonary insufficiency, although a trend toward decreased obstruction was present only in all post-treatment conditions. There was no improvement noted in pulmonary function in animals that received a higher dose of tiotropium bromide. CONCLUSIONS: This study describes a contribution of acetylcholine to the airway constrictive and lumenal obstructive response after inhalation injury and identifies low-dose nebulization of tiotropium bromide as a potentially efficacious therapy for burn patients with severe inhalation injury.

Acute secretory cell toxicity and epithelial exfoliation after smoke inhalation injury in sheep: an electron and light microscopic study.

Smoke inhalation injury promotes exfoliation of the upper airway columnar epithelium. Tracheal tissues from sheep 30 min after smoke exposure show intact epithelial areas, areas of epithelial disruption with loss of columnar cells and areas denuded of columnar cells. In intact areas detaching ciliated cells can be seen raised above the apical surface. This study aims to assess cell-specific toxicity by examining intact epithelium after inhalation injury. The junctional adhesion integrity between columnar and basal cells and the type of cells initially being displaced were also studied using light (LM) and transmission electron microscopy (TEM). TEM assessment of intact areas of sheep tracheal tissue (n=3) 30 min after exposure showed secretory cell toxicity including extrusion of cytoplasmic contents. In cells with severe secretory cell cytoplasmic disruption, loss of desmosomal junctions between the secretory and adjacent ciliated cells was evident. The number of desmosomes visible between columnar cells and basal cells was reduced (2.8 ± 1.8) in smoke-exposed animals compared to those in uninjured animals (5.0 ± 2.7), p=0.008. Serial sections of intact regions found 52 cells being displaced from the epithelium. All detaching cells were identified as ciliated cells. These studies show that the acute effects of inhalation injury include selective secretory cell toxicity which is associated with loss of junctional adhesion mechanisms and displacement of ciliated cells. Improved understanding of acute hypersecretory responses and epithelial integrity after exposure to toxic agents may improve understanding of epithelial fragility in airway disease.

Substance P antagonist CP-96345 blocks lung vascular leakage and inflammation more effectively than its stereoisomer CP-96344 in a mouse model of smoke inhalation and burn injury.

The recently developed murine model of smoke inhalation and burn (SB) injury was used to study the effect of the substance-P antagonist CP96345. C57BL/6 mice were pre-treated with an i.v. dose of a specific NK-1 receptor antagonist, CP9635, or its inactive enantiomer, CP96344, (10 mg/Kg) 1 h prior to SB injury per protocol (n = 5). Mice were anesthetized and exposed to cooled cotton smoke, 2X 30 s, followed by a 40% total body surface area flame burn per protocol. At 48 h after SB injury Evans Blue (EB) dye and myeloperoxidase (MPO) were measured in lung after vascular perfusion. Lungs were also analyzed for hemoglobin (Hb) and wet/dry weight ratio. In the current study, CP96345 pre-treatment caused a significant decrease in wet/dry weight ratio (23%, p = 0.048), EB (31%, p = 0.047), Hb (46%, p = 0.002), and MPO (54%, p = 0.037) levels following SB injury compared to animals with SB injury alone. CP-96344 pre-treatment caused an insignificant decrease in wet/dry weight ratio (14%, p = 0.18), EB (16%, p = 0.134), Hb (9%, p = 0.39), and an insignificant increase in MPO (4%, p = 0.79) as compared to mice that received SB injury alone. As expected, levels of EB, Hb, MPO, and wet/dry weight ratios were all significantly (p < 0.05) increased 48 h following SB injury alone compared to respective sham animals. In conclusion, the current study indicates that pre-treatment with a specific NK-1R antagonist CP-96345 attenuates the lung injury and inflammation induced by SB injury in mice.

Club Cell Protein, CC10, Attenuates Acute Respiratory Distress Syndrome Induced by Smoke Inhalation.

OBJECTIVES: To evaluate the dose effects of Recombinant human Club cell 10-kDa protein (rhCC10) on lung function in a well-characterized ovine model of acute respiratory distress syndrome (ARDS) induced by smoke inhalation injury (SII); specifically, the potential of rhCC10 protein to control the inflammatory response and protect pulmonary tissue and function following SII. DESIGN: Randomized, controlled, prospective, and large animal translational studies. SETTING: University large animal intensive care unit. SUBJECTS: Thirty-six adult female sheep were surgically prepared and allocated into five groups (Sham (no SII), n = 6; 1 mg/kg/d CC10, n = 8; 3 mg/kg/d CC10, n = 7; 10 mg/kg/d CC10, n = 8; Control SII, n = 7). INTERVENTIONS: All groups except the sham group were subjected to SII with cooled cotton smoke. Then, the animals were placed on a ventilator, treated with 1, 3, and 10 mg/kg/d of intravenous rhCC10 or vehicle, divided evenly into two administrations per day every 12 h, fluid resuscitated, and monitored for 48 h in a conscious state. MEASUREMENTS AND MAIN RESULTS: The group treated with 10 mg/kg/d rhCC10 attenuated changes in the following variables: PaO2/FiO2 ratio, oxygenation index, and peak inspiratory pressure; neutrophil content in the airway and myeloperoxidase levels; obstruction of the large and small airways; systemic leakage of fluid and proteins, and pulmonary edema. CONCLUSIONS: In this study, high-dose rhCC10 significantly attenuated ARDS progression and lung dysfunction and significantly reduced systemic extravasation of fluid and proteins, normalizing fluid balance. Based on these results, rhCC10 may be considered a novel therapeutic option for the treatment of SII-induced ARDS.

Combined neuronal and inducible nitric oxide synthase inhibition in ovine acute lung injury.

OBJECTIVE: Acute lung injury with subsequent pneumonia and sepsis represents a major cause of morbidity and mortality in thermally injured patients. Production of nitric oxide by the neuronal and inducible nitric oxide synthase may be critically involved in the pathophysiology of the disease process at different time points, and thus specific inhibition at different times may represent an effective treatment regimen. DESIGN: Prospective, controlled, randomized trial. SETTING: University research laboratory. SUBJECTS: Eighteen chronically instrumented, adult, female sheep. INTERVENTIONS: Following baseline measurements, the animals were allocated to either sham-injured, nontreated controls (sham), injured, nontreated controls (control), or injured animals treated with continuous infusion of 7-nitroindazole, a specific neuronal nitric oxide synthase inhibitor, during the first 12 hrs postinjury and infusion of BBS-2, a specific inducible nitric oxide synthase inhibitor, during the next 12 hrs. Injury was induced by 48 breaths of cotton smoke and subsequent instillation of Pseudomonas aeruginosa into the lungs. All sheep were mechanically ventilated and fluid resuscitated for the entire duration of the 24-hr experiment. MEASUREMENTS AND MAIN RESULTS: The injury induced severe pulmonary dysfunction, which was associated with increases in lung edema formation, airway obstruction, and vascular endothelial growth factor, 3-nitrotyrosine, and poly(adenosine diphosphate ribose) expression in lung tissue. The treatment reduced the degree of airway obstruction and improved pulmonary gas exchange, whereas the development of lung edema was not affected. The increases in lung tissue vascular endothelial growth factor, 3-nitrotyrosine, and poly(ribose) expression were attenuated by the treatment. CONCLUSIONS: The combination of early neuronal nitric oxide synthase and delayed inducible nitric oxide synthase inhibition shows potential benefit in ovine acute lung injury by reducing nitrosative stress in the lung and limiting the degree of airway obstruction.

Role of calcitonin gene-related peptide (CGRP) in ovine burn and smoke inhalation injury.

Concomitant smoke inhalation trauma in burn patients is a serious medical problem. Previous investigations in our sheep model revealed that these injuries lead to significant airway hyperemia, enhanced pulmonary fluid extravasation, and severely impaired pulmonary function. However, the pathophysiological mechanisms are still not fully understood. The lung is innervated by sensory nerves containing peptides such as substance P and calcitonin gene-related peptide. Noxious stimuli in the airways can induce a neurogenic inflammatory response, which has previously been implicated in several airway diseases. Calcitonin gene-related peptide is known to be a potent vasodilator. We hypothesized that calcitonin gene-related peptide is also a mediator of the pulmonary reaction to toxic smoke and planned experiments to evaluate its role in this model. We tested the effects of pretreatment with a specific antagonist of the major receptor for calcitonin gene-related peptide (BIBN4096BS; 32 microg/kg, followed by continuous infusion of 6.4 microg.kg(-1).h(-1)) until the animal was killed 48 h after injury in an established ovine model of burn (40% total body surface, third degree) and smoke inhalation (48 breaths, <40 degrees C) injury. In treated animals (n = 7), the injury-related increases in tracheal blood flow and lung lymph flow were significantly attenuated compared with untreated controls (n = 5). Furthermore, the treatment significantly attenuated abnormalities in respiratory gas exchange. The data suggest that calcitonin gene-related peptide contributes to early airway hyperemia, transvascular fluid flux, and respiratory malfunction following ovine burn and smoke inhalation injury. Future studies will be needed to clarify the potential therapeutic benefit for patients with this injury.

Pulmonary expression of nitric oxide synthase isoforms in sheep with smoke inhalation and burn injury.

Previous studies have indicated increased plasma levels of inducible nitric oxide synthase in lung. This study further examines the pulmonary expression of nitric oxide synthase (NOS) isoforms in an ovine model of acute lung injury induced by smoke inhalation and burn injury (S+B injury). Female range bred sheep (4 per group) were sacrificed at 4, 8, 12, 24, and 48 hours after injury and immunohistochemistry was performed in tissues for various NOS isoforms. The study indicates that in uninjured sheep lung, endothelial (eNOS) is constitutively expressed in the endothelial cells associated with the airways and parenchyma, and in macrophages. Similarly, neuronal (nNOS) is constitutively present in the mucous cells of the epithelium and in neurons of airway ganglia. In uninjured lung, inducible (iNOS) was present in bronchial secretory cells and macrophages. In tissue after S+B injury, new expression of iNOS was evident in bronchial ciliated cells, basal cells, and mucus gland cells. In the parenchyma, a slight increase in iNOS immunostaining was seen in type I cells at 12 and 24 hours after injury only. Virtually no change in eNOS or nNOS was seen after injury.