Anakinra (IL-1R antagonist) lowers pulmonary artery pressure in a neonatal surfactant depleted piglet model.

In acute respiratory distress syndrome (ARDS) with pulmonary hypertension, interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) are involved in the pulmonary inflammatory reaction. The purpose of this study was to determine whether systemic and aerosolized administered IL-1 receptor antagonist (IL-1Ra) Anakinra (Kineret) improves lung mechanics and pulmonary artery pressure in surfactant depleted newborn piglets. After induction of acute lung injury by lung lavage, neonatal piglets received repetitive treatment of either aerosolized IL-1Ra (IL-1Ra-Aerosol) or intravenous IL-1Ra (IL-1Ra-i.v.), or saline solution as control. IL-1Ra given as aerosol or intravenously significantly reduced mean pulmonary artery pressure (MPAP) but did not influence mean systemic arterial pressure (MAP) compared with the control group. IL-1 beta and IL-8 mRNA expressions normalized to beta-actin and hypoxanthine-guanine-phosphoribosyl transferase were significantly reduced in the IL-1Ra-Aerosol group but not in IL-1Ra-i.v. group compared to the control group. The lung injury score was not significantly different between IL-1Ra groups and the control group. Application of aerosolized IL-1Ra reduced MPAP without affecting MAP in a piglet model of surfactant depletion with pulmonary hypertension. Furthermore, there is evidence for reduction of early pro-inflammatory pulmonary reaction.

Comparison of aerosol therapy with different perfluorocarbons in surfactant-depleted animals.

OBJECTIVE: The study investigates the effectiveness of aerosol treatment on gas exchange and pulmonary inflammatory reaction using perfluorocarbons with different molecular structure and vapor pressure. DESIGN: Experimental, prospective, randomized, controlled study. SETTING: Experimental laboratory at a university hospital. SUBJECTS: Twenty anesthetized neonatal piglets assigned to four groups. INTERVENTIONS: After establishment of lung injury by bronchoalveolar lavage, piglets either received aerosolized FC77 (n = 5), perfluorooctylbromide (n = 5), or FC43 (n = 5, 10 mL x kg(-1) x hr(-1) for 2 hrs) or intermittent mandatory ventilation (control, n = 5). Thereafter, animals were supported for another 6 hrs. MEASUREMENTS AND MAIN RESULTS: Pao2 significantly improved in the perfluorocarbon groups compared with control (p < .01). Final Pao2 (mean +/- SEM) was FC77, 406 +/- 27 mm Hg; perfluorooctylbromide, 332 +/- 32 mm Hg; FC43, 406 +/- 19 mm Hg; control, 68 +/- 8 mm Hg. Paco2 and mean pulmonary arterial pressure were lower in all perfluorocarbon groups compared with control. The ratio of terminal dynamic compliance to total compliance was significantly higher in the FC77 than in the FC43, perfluorooctylbromide, and control groups. Relative gene expression of interleukin-1beta, interleukin-8, P-selectin, E-selectin, and intercellular adhesion molecule-1 in lung tissue was determined by TaqMan real time polymerase chain reaction normalized to hypoxanthineguanine-phosphoribosyl-transferase and was shown to be reduced by all perfluorocarbons. CONCLUSIONS: Aerosol treatment with all the perfluorocarbons investigated improved gas exchange and reduced pulmonary inflammatory reaction independently from molecular structure and vapor pressure of the perfluorocarbons. Although differences in vapor pressure and molecular structure may account for varying optimal dosing strategies, several different perfluorocarbons were shown to be principally suitable for aerosol treatment.

Pilot intervention: aerosolized adrenomedullin reduces pulmonary hypertension.

In pulmonary hypertension, systemic infusion of adrenomedullin (ADM), a potent vasodilator peptide, leads to pulmonary vasodilatation. However, systemic blood pressure declines alike. The present study investigated the effect of aerosolized ADM on pulmonary arterial pressure in surfactant-depleted newborn piglets with pulmonary hypertension. Animals randomly received aerosolized ADM (ADM, n = 6), aerosolized ADM combined with intravenous application of NG-nitro-l-arginine methylester to inhibit nitric-oxide (NO) synthases (ADM + l-NAME, n = 5), or aerosolized normal saline solution (control, n = 6). Aerosol therapy was performed in 30-min intervals for 5 h. After a total experimental period of 8 h, mRNA expression of endothelial and inducible NO synthase and endothelin-1 (ET-1) in lung tissue was quantified using TaqMan real-time polymerase chain reaction. Aerosolized ADM reduced mean pulmonary artery pressure (MPAP) compared with control (p < 0.001; at the end of the study, Delta-MPAP -13.5 +/- 1.4 versus -6.2 +/- 2.4 mm Hg). PaO2 significantly increased in the ADM (DeltaPaO2 243.3 mm Hg) and the ADM + l-NAME group (DeltaPaO2 217.4 mm Hg) compared with the control group (DeltaPaO2 82.9 mm Hg; p < 0.001). Aerosolized ADM did not influence mean systemic arterial pressure (baseline 63.2 +/- 2.7 versus end of the study 66.3 +/- 6.5 mm Hg; not significant). NO synthases gene expressions were 20 to 30% lower with ADM compared with control. ET-1 gene expression was significantly reduced (>50%) after ADM aerosol therapy (p < 0.001). Aerosolized adrenomedullin significantly reduced MPAP without lowering the systemic arterial pressure and improved profoundly the arterial oxygen tension. This effect seems to be mediated at least in part by the reduction of ET-1.

Aerosolized adrenomedullin suppresses pulmonary transforming growth factor-beta1 and interleukin-1 beta gene expression in vivo.

The effect of aerosolized adrenomedullin on interleukin-1 beta and transforming growth factor (TGF)-beta1 mRNA and protein expression was studied in surfactant depleted piglets, receiving aerosolized adrenomedullin (adrenomedullin, n=6), aerosolized adrenomedullin plus i.v. N(G)-nitro-L-arginine-methylester (adrenomedullin+L-NAME, n=5), or aerosolized saline solution (control, n=6). After 8 h of aerosol interval therapy, mRNA expression of interleukin-1 beta and TGF-beta1 in lung tissue was quantified normalized to beta-actin and hypoxanthine-guanine-phosphoribosyl-transferase by real-time polymerase chain reaction (PCR). Interleukin-1 beta and TGF-beta1 protein concentration in lung tissue was quantified by enzyme-linked immunosorbent assay (ELISA). In the adrenomedullin group, interleukin-1 beta and TGF-beta1 mRNA expression was lower than in controls. Reduction for interleukin-1 beta/beta-actin was 56% (p<0.001), for interleukin-1 beta/hypoxanthine-guanine-phosphoribosyl-transferase 60% (p<0.001), for TGF-beta1/beta-actin 65.5% (p<0.001), and for TGF-beta1/hypoxanthine-guanine-phosphoribosyl-transferase 56.2% (p<0.001). Mean interleukin-1 beta protein expression was different between the groups, p<0.05 (adrenomedullin 601+/-61, Control 836+/-88 pg/mg protein). L-NAME did not antagonize adrenomedullin effect on TGF-beta1 mRNA. In conclusion, aerosolized adrenomedullin reduced pulmonary inflammatory and pro-fibrotic response.

Aerosolized perfluorocarbon reduces adhesion molecule gene expression and neutrophil sequestration in acute respiratory distress.

In acute respiratory distress syndrome, neutrophil migration into the lung plays a key role in the development of lung injury. To study the effect of different modes of ventilation with perfluorocarbon (FC77), intrapulmonary neutrophil accumulation and mRNA expression of E-selectin, P-selectin and intercellular adhesion molecule-1 (ICAM-1), mediating leukocyte sequestration, were measured in surfactant depleted piglets. After bronchoalveolar lavage, 20 animals either received aerosolized perfluorocarbon (Aerosol-PFC), partial liquid ventilation (PLV) with perfluorocarbon at functional residual capacity filling volume (FRC-PLV) or at low volume (LV-PLV) or intermittent mandatory ventilation (control). After 2 h of perfluorocarbon application, intermittent mandatory ventilation was continued for 6 h. In the Aerosol-PFC group, all measured adhesion molecules showed a significantly reduced gene expression compared to controls. FRC-PFC treatment was effective in significantly diminishing P-selectin and ICAM-1 mRNA expression. Relative lung tissue neutrophil counts were significantly reduced in the Aerosol-PFC and the FRC-PLV group. Treatment with aerosolized perfluorocarbon is at least as effective as partial liquid ventilation at FRC volume in reducing pulmonary adhesion molecule expression and neutrophil accumulation in acute respiratory distress syndrome.

Aerosolized perfluorocarbon suppresses early pulmonary inflammatory response in a surfactant-depleted piglet model.

The effect of new ventilation strategies on initial pulmonary inflammatory reaction was studied in a surfactant-depleted piglet model. Sixty minutes after induction of lung injury by bronchoalveolar lavage, piglets received either aerosolized FC77 (aerosol-PFC, 10 mL/kg/h, n = 5) or partial liquid ventilation (PLV) with FC77 at functional residual capacity volume (FRC-PLV, 30 mL/kg, n = 5), or at low volume (LV-PLV, 10 mL/kg per hour, n = 5), or intermittent mandatory ventilation (control, n = 5). After 2 h, perfluorocarbon application was stopped and intermittent mandatory ventilation continued for 6 h. After a total experimental period of 8 h, animals were killed and lung tissue obtained. mRNA expression of IL-1beta, IL-6, IL-8, and TGF-beta in porcine lung tissue was quantified using TaqMan real-time PCR and normalized to beta-actin (A) and hypoxanthine-guanine-phosphoribosyl-transferase (H). In the aerosol-PFC group, IL-1beta, IL-6, IL-8, and transforming growth factor (TGF)-beta mRNA expression in lung tissue was significantly lower than in the control group. Reduction was 95% for IL-1beta/H (p < 0.001), 73% for IL-6/H (p < 0.05), 87% for IL-8/H (p < 0.001), and 38% for TGF-beta/H (p < 0.01). A lower mRNA gene expression was also determined for IL-1beta and IL-8 when the aerosol-PFC group was compared with the LV-PLV group [91% for IL-1beta/H (p < 0.001), 75% for IL-8/H (p < 0.001)]. In the FRC-PLV group, mRNA expression of IL-1beta was significantly lower than in the control (p < 0.05) and LV-PLV (p < 0.01) group. In a surfactant-depleted piglet model, aerosol therapy with perfluorocarbon but not LV-PLV reduces the initial pulmonary inflammatory reaction at least as potently as PLV at FRC volume.