Early Hypoxic Respiratory Failure in Extreme Prematurity: Mortality and Neurodevelopmental Outcomes.

OBJECTIVES: To evaluate the survival and neurodevelopmental impairment (NDI) in extremely low birth weight (ELBW) infants at 18 to 26 months with early hypoxemic respiratory failure (HRF). We also assessed whether African American infants with early HRF had improved outcomes after exposure to inhaled nitric oxide (iNO). METHODS: ELBW infants ≤1000 g and gestational age ≤26 weeks with maximal oxygen ≥60% on either day 1 or day 3 were labeled as "early HRF" and born between 2007 and 2015 in the Neonatal Research Network were included. Using a propensity score regression model, we analyzed outcomes and effects of exposure to iNO overall and separately by race. RESULTS: Among 7639 ELBW infants born ≤26 weeks, 22.7% had early HRF. Early HRF was associated with a mortality of 51.3%. The incidence of moderate-severe NDI among survivors was 41.2% at 18 to 26 months. Mortality among infants treated with iNO was 59.4%. Female sex (adjusted odds ratio [aOR]: 2.4, 95% confidence interval [CI]: 1.8-3.3), birth weight ≥720 g (aOR: 2.3, 95% CI: 1.7-3.1) and complete course of antenatal steroids (aOR: 1.6, 95% CI: 1.1-2.2) were associated with intact survival. African American infants had a similar incidence of early HRF (21.7% vs 23.3%) but lower exposure to iNO (16.4% vs 21.6%). Among infants with HRF exposed to iNO, intact survival (no death or NDI) was not significantly different between African American and other races (aOR: 1.5, 95% CI: 0.6-3.6). CONCLUSIONS: Early HRF in infants ≤26 weeks' gestation is associated with high mortality and NDI at 18 to 26 months. Use of iNO did not decrease mortality or NDI. Outcomes following iNO exposure were not different in African American infants.

Inducible nitric oxide synthase inhibition attenuates physical stress-induced lung hyper-responsiveness and oxidative stress in animals with lung inflammation.

Mechanisms involved in stress-induced asthmatic alterations have been poorly characterised. We assessed whether inducible nitric oxide synthase (iNOS) inhibition modulates the stress-amplified lung parenchyma responsiveness, oxidative stress and extracellular matrix remodelling that was previously increased by chronic lung inflammation. Guinea pigs were subjected to 7 exposures to ovalbumin (1-5 mg/ml) or saline (OVA and SAL groups) over 4 weeks. To induce behavioural stress, animals were subjected to a forced swimming protocol (5 times/week, over 2 weeks; SAL-Stress and OVA-Stress groups) 24 h after the 4th inhalation. 1400W (iNOS-specific inhibitor) was administered intraperitoneally in the last 4 days of the protocol (SAL-1400W, OVA-1400W, SAL-Stress+1400W and OVA-Stress+1400W groups). Seventy-two hours after the last inhalation, animals were anaesthetised and exsanguinated, and adrenal glands were removed. Lung tissue resistance and elastance were evaluated by oscillatory mechanics and submitted for histopathological evaluation. Stressed animals had higher adrenal weights compared to non-stressed groups, which were reduced by 1400W treatment. Behavioural stress in sensitised animals amplified the resistance and elastance responses after antigen challenge, numbers of eosinophils and iNOS+ cells, actin content and 8-iso-PGF2α density in the distal lung compared to the OVA group. 1400W treatment in ovalbumin-exposed and stressed animals reduced lung mechanics, iNOS+ cell numbers and 8-iso-PGF2α density compared to sensitised and stressed animals that received vehicle treatment. We concluded that stress amplifies the distal lung constriction, eosinophilic inflammation, iNOS expression, actin content and oxidative stress previously induced by chronic lung inflammation. iNOS-derived NO contributes to stress-augmented lung tissue functional alterations in this animal model and is at least partially due to activation of the oxidative stress pathway.

A prospective, single-blind, multicenter, dose escalation study of intracoronary iNOS lipoplex (CAR-MP583) gene therapy for the prevention of restenosis in patients with de novo or restenotic coronary artery lesion (REGENT I extension).

Neointimal hyperplasia causing recurrent stenosis is a limitation of the clinical utility of percutaneous transluminal coronary interventions (PCI). Nitric oxide (NO) inhibits smooth muscle cell proliferation, platelet activation, and inflammatory responses, all of which have been implicated in the pathogenesis of restenosis. In animals, neointimal proliferation after balloon injury has been shown to be effectively reduced by gene transfer of the inducible NO synthase (iNOS). The primary objective of this first multicenter, prospective, single-blind, dose escalation study was to obtain safety and tolerability information of the iNOS lipoplex (CAR-MP583) gene therapy for reducing restenosis following PCI. Local coronary intramural CAR-MP583 delivery was achieved using the Infiltrator balloon catheter. A total of 30 patients were treated in the study (six patients, 0.5 µg; six patients, 2.0 µg; six patients, 5.0 µg; and 12 patients, 10 µg). There were no complications related to local application of CAR-MP583. In one patient, PCI procedure-related transient vessel occlusion occurred with consecutive troponin elevation. There were no signs of inflammatory responses or hepatic or renal toxicity. No dose relationship was seen with regard to adverse events across the dose groups. Thus, coronary intramural lipoplex-enhanced iNOS gene therapy during PCI is feasible and appears to be safe. These initial clinical results are encouraging to support further clinical research, in particular in conjunction with new local drug delivery technologies.

Beta cell cytoprotection using lentiviral vector-based iNOS-specific shRNA delivery.

Cytokine-induced beta cell pathophysiology is characterised by the induction of iNOS expression. Inhibition of iNOS expression protects beta cells from cytokine-mediated destruction. The development of vector-based shRNA strategies capable of stably suppressing iNOS expression may provide a novel platform to protect beta cells from cytokine toxicity. In this report the utility of lentiviral shRNA vectors to silence iNOS expression was evaluated with respect to insulinoma cell viability, the induction of iNOS expression and the accumulation of nitrite in a cytokine-induced beta cell toxicity model. Here, we report for the first time on the use of lentiviral vector-based shRNA delivery to efficiently suppress the IL-1beta-mediated induction of iNOS expression, the accumulation of nitrite and provide significant protection against the cytotoxic effects of IL-1beta exposure. Moreover, non-specific knockdown of endogenous beta cell nNOS did not occur.