Monitoring Antioxidant Enzyme Activity during Exacerbations of Chronic Obstructive Pulmonary Disease

Figures & data

Figure 1. Flowchart showing the study profile in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). EBC: exhaled breath condensate.

Table 1. Demographic and clinical characteristics of study subjects.

	Healthy controls	Stable COPD	AECOPD
Subjects (n)	23	24	36
Sex (male/female, n)	13/10	14/10	19/17
Age (years)	59.3 ± 2.8	64.5 ± 2.6	68.5 ± 3.1
Smoking (pack-years)	40.1 ± 2.5	46.5 ± 4.3	44.2 ± 2.3
GOLD stages (n, %)	–
I–II.		14 (58)	16 (44)
III–IV.		10 (42)	20 (56)
			At admission	After treatment
Pulmonary function
FVC (L)	3.96 ± 0.17	3.66 ± 0.20	1.99 ± 0.12	2.25 ± 0.13*
FVC (% predicted)	101.6 ± 3.3	79.3 ± 3.1	69.9 ± 3.34	74.8 ± 3.24*
FEV1 (L)	3.1 ± 0.12	1.87 ± 0.16	0.93 ± 0.08	1.09 ± 0.09***
FEV1 (% predicted)	107.3 ± 2.88	65.3 ± 4.92	41.9 ± 3.78	46.6 ± 3.4***
FEV1/FVC	0.78 ± 0.01	0.51 ± 0.03	0.47 ± 0.03	0.48 ± 0.02*
Blood gases
PaCO2 (kPa)	5.23 ± 0.09	5.09 ± 0.12	5.69 ± 0.16	6.03 ± 0.18
PaO2 (kPa)	9.9 ± 0.51	8.51 ± 0.21	6.87 ± 0.19	7.77 ± 0.21*
FENO (ppb)^†	14.0 (10.4–20.3)	16.2 (11.0–25.8)	19.2 (9.78–33.1)	10.9 (7.13–16.1)**

Data are presented as mean ± SEM unless stated otherwise. FVC: forced vital capacity, FEV₁: forced expiratory volume in one second, FENO: fractional exhaled nitric oxide, ppb: parts per billion, PaCO₂: arterial carbon dioxide tension, PaO₂: arterial oxygen tension, GOLD: Global Initiative for Chronic Obstructive Pulmonary Disease. *p < 0.05, **p < 0.01, and ***p < 0.005 vs. admission, ^†median (interquartile ranges).

Figure 2. Superoxide dismutase (SOD) (a) and catalase (CAT) (b) activities in sputum supernatant of healthy controls (controls), stable COPD patients (stable), and AECOPD patients at the time of acute exacerbation (ex) and after hospital treatment (treat). Horizontal bars represent median values. *p < 0.05 and **p < 0.01 vs. stable COPD patients, ^§p < 0.001 vs. healthy controls, ^#p < 0.05 and ^##p < 0.005 vs. acute exacerbation.

Table 2. Superoxide dismutase (SOD) and catalase (CAT) activities in sputum and serum of healthy controls, stable COPD patients, and AECOPD patients at the time of acute exacerbation and after hospital treatment.

			AECOPD
Antioxidants	Healthy controls	Stable COPD	At admission	After treatment
Sputum
SOD (U/mL)	0.01 (0–0.043)	0.038 (0.002–0.146)	0.142 (0.053–0.81)^§**	0.094 (0.046–0.45)^#
CAT (nmol/min/mL)	5.2 (0.44–16.6)	10.2 (2.9–40.6)	48.7 (18.7–72.6)^§*	28.0 (7.3–60.4)^##
Serum
SOD (U/mL)	7.69 (6.31–12.7)	9.94 (6.93–13.4)	6.14 (3.53–12.8)	8.28 (6.04–11.8)
CAT (nmol/min/mL)	39.4 (5.94–57.7)	42.5 (5.15–58.3)	36.6 (4.65–58.9)	31.2 (4.77–50.0)

Data are presented as median (interquartile ranges). *p < 0.05 and **p < 0.01 vs. stable COPD patients, ^§p < 0.001 vs. healthy controls, ^#p < 0.05 and ^##p < 0.005 vs. at admission.

Table 3. Correlations between sputum superoxide dismutase (SOD)/catalase (CAT) activities and clinical variables, sputum inflammatory cells, and sputum MDA levels in stable COPD patients and in those with AECOPD.

Variables	Sputum SOD		Sputum CAT
	r value	p value	r value	p value
Stable COPD
PaO2 (kPA)	–0.123	0.559	−0.228	0.308
FEV1 (% predicted)	–0.114	0.587	−0.32	0.166
Sputum
Total cell counts (×10^6/g)	0.402	0.052	0.642	0.003*
Neutrophils (×10^6/g)	0.435	0.033*	0.543	0.016*
MDA (nmol/L)	–0.004	0.986	0.009	0.973
AECOPD (at admission)
PaO2 (kPA)	–0.02	0.242	–0.047	0.829
FEV1 (% predicted)	–0.116	0.536	–0.271	0.223
Sputum
Total cell counts (×10^6/g)	0.432	0.005*	0.447	0.017*
Neutrophils (×10^6/g)	0.557	<0.001*	0.514	0.007*
Neutrophils (%)	0.376	0.024*	0.493	0.009*
Lymphocytes (×10^6/g)	0.417	0.012*	0.392	0.048*
MDA (nmol/L)	0.402	0.023*	0.48	0.015*
AECOPD (at discharge)
PaO2 (kPA)	–0.102	0.626	–0.121	0.622
FEV1 (% predicted)	–0.167	0.361	–0.289	0.192
Sputum
Total cell counts (×10^6/g)	0.054	0.746	0.491	0.007*
Neutrophils (×10^6/g)	0.249	0.156	0.468	0.014*
Neutrophils (%)	0.140	0.407	0.442	0.018*
Lymphocytes (×10^6/g)	–0.183	0.454	0.079	0.696
MDA (nmol/L)	0.424	0.019*	0.498	0.011*

FEV₁: forced expiratory volume in one second, PaO₂: arterial oxygen tension, MDA: malondialdehyde, *significant correlations.