Anti-inflammatory effects of inhaled carbon monoxide in patients with COPD: a pilot study

Abstract

In vitro and in vivo studies have shown that carbon monoxide (CO) has both antiinflammatory and anti-oxidant capacities. Since chronic obstructive pulmonary disease (COPD) is characterised by inflammation and oxidative stress, low-dose CO could be of therapeutic use. The aim of the present study was to investigate the feasibility and anti-inflammatory effects of 100-125 ppm CO inhalation in patients with stable COPD.In total, 20 ex-smoking COPD patients with post-bronchodilator forced expiratory volume in one second (FEV1) .1.20 L and FEV1/forced vital capacity ,70% were enrolled in a randomised, placebo-controlled, crossover study. Effects on inflammation were measured in induced sputum and blood.CO inhalation was feasible and patients' vital signs were unaffected; 2 h?day -1 inhalation of lowdose CO on 4 consecutive days led to a maximal individual carboxyhaemoglobin level of 4.5%. Two exacerbations occurred in the CO period. CO inhalation led to trends in reduced sputum eosinophils (median reduction 0.25% point) and improved responsiveness to methacholine (median provocative concentration causing a 20% fall in FEV1 0.85 versus 0.63 mg?mL -1 ).Inhalation of 100-125 ppm carbon monoxide by patients with chronic obstructive pulmonary disease in a stable phase was feasible and led to trends in reduction of sputum eosinophils and improvement of responsiveness to methacholine. Further studies need to confirm the safety and efficacy in inflammatory lung diseases.

Heme Oxygenase-1/Carbon Monoxide

“…In this study, ex-smoking patients with stable COPD were subjected to CO inhalation (100-125 ppm for 2 h/d on 4 consecutive days), which produced a maximal individual CO-Hb level of 4.5%. Inhalation of CO by patients with stable COPD led to trends in reduction of sputum eosinophils and improvement of methacholine responsiveness (117). Further studies are required to confirm the safety and efficacy of CO inhalation as a treatment for inflammatory lung diseases.…”

“…An ongoing phase II trial has addressed the safety of inhaled CO during renal transplantation (Clinicaltrials.gov #NCT00531856). A report on a recently completed clinical trial demonstrates the feasibility of administering a low dose of inhaled CO to humans with chronic obstructive pulmonary disease (COPD) (Clinicaltrials.gov #NCT00122694) (117). In this study, ex-smoking patients with stable COPD were subjected to CO inhalation (100-125 ppm for 2 h/d on 4 consecutive days), which produced a maximal individual CO-Hb level of 4.5%.…”

Analysis of the Bacterial Response to Ru(CO)3Cl(Glycinate) (CORM-3) and the Inactivated Compound Identifies the Role Played by the Ruthenium Compound and Reveals Sulfur-Containing Species as a Major Target of CORM-3 Action

“…However, utilizing CO gas as a therapeutic tool has proven difficult due to its toxic properties and the systemic delivery methods used for administration (5). CO-releasing molecules (CO-RMs) have been developed for over 10 years in an attempt to harness the beneficial properties of CO while minimizing its toxic effects.…”

Inflation with carbon monoxide in rat donor lung during cold ischemia phase ameliorates graft injury

“…The CO concentration was maintained in therapeutic concentration (250-500 ppm 9,10 ) when replaced every 30 min during this study. Additionally, CO has already been used in clinical treatments such as endotoxemia and chronic obstructive pulmonary diseases, 18,19 but the dosage was lower and the applied time was shorter. Therefore, the method used in this study should be explored further before being applied in clinical practice.…”