Abstract
BackgroundThere is accumulating evidence that oxidative stress plays an important role in the pathophysiology of chronic obstructive pulmonary disease (COPD). One current hypothesis is that the increased oxidant burden in these patients is not adequately counterbalanced by the lung antioxidant systems.ObjectiveTo determine the levels of oxidised human serum albumin (HSA) in COPD lung explants and the effect of oxidation on HSA degradation using an ex vivo lung explant model.MethodsParenchymal lung tissue was obtained from 38 patients (15F/23M) undergoing lung resection and stratified by smoking history and disease using the GOLD guidelines and the lower limit of normal for FEV1/FVC ratio. Lung tissue was homogenised and analysed by ELISA for total levels of HSA and carbonylated HSA. To determine oxidised HSA degradation lung tissue explants were incubated with either 200 μg/ml HSA or oxidised HSA and supernatants collected at 1, 2, 4, 6, and 24 h and analysed for HSA using ELISA and immunoblot.ResultsWhen stratified by disease, lung tissue from GOLD II (median = 38.2 μg/ml) and GOLD I (median = 48.4 μg/ml) patients had lower levels of HSA compared to patients with normal lung function (median = 71.9 μg/ml, P < 0.05). In addition the number of carbonyl residues, which is a measure of oxidation was elevated in GOLD I and II tissue compared to individuals with normal lung function (P < 0.05). When analysing smoking status current smokers had lower levels of HSA (median = 43.3 μg/ml, P < 0.05) compared to ex smokers (median = 71.9 μg/ml) and non-smokers (median = 71.2 μg/ml) and significantly greater number of carbonyl residues per HSA molecule (P < 0.05). When incubated with either HSA or oxidised HSA lung tissue explants rapidly degraded the oxidised HSA but not unmodified HSA (P < 0.05).ConclusionWe report on a reliable methodology for measuring levels of oxidised HSA in human lung tissue and cell culture supernatant. We propose that differences in the levels of oxidised HSA within lung tissue from COPD patients and current smokers provides further evidence for an oxidant/antioxidant imbalance and has important biological implications for the disease.
Highlights
There is accumulating evidence that oxidative stress plays an important role in the pathophysiology of chronic obstructive pulmonary disease (COPD)
We propose that differences in the levels of oxidised Human serum albumin (HSA) within lung tissue from COPD patients and current smokers provides further evidence for an oxidant/antioxidant imbalance and has important biological implications for the disease
Relationship between baseline levels of human serum albumin and Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) I & II Parenchymal lung tissue from 38 individuals categorised as GOLD I, II or patients with no evidence of airway obstruction, was homogenised and the levels of HSA analysed using ELISA
Summary
There is accumulating evidence that oxidative stress plays an important role in the pathophysiology of chronic obstructive pulmonary disease (COPD). Human serum albumin (HSA) is a single nonglycosylated polypeptide containing 35 cysteine residues all involved in the formation of stabilising disulphide bonds except 34cysteine In plasma, this free thiol group is quantitatively the most important scavenger of oxidants [4,5,6], and is an important antioxidant within the body[7]. In particular oxidised HSA is a reliable marker of oxidative stress in patients with chronic renal failure and individuals on hemodialysis therapy [12]. In light of these findings the quantification of carbonyl residues may provide further evidence to support a role of oxidative stress in COPD pathology. We have investigated the effect of oxidation on HSA degradation within human lung tissue explants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
