Constant-load exercise decreases the serum concentration of myeloperoxidase in healthy smokers and smokers with COPD

Figures & data

Table 1 Demographic and physiological parameters

	Healthy smokers (n=23)	COPD smokers (n=23)
Men/women	6/17	6/17
Age (years)	54 (42, 65)	55 (46, 68)
Weight (kg)	79.6±14.0	77.3±12.3
BMI (kg/m^2)	25.4±2.5	25.2±3.4
Pack-years	39±23.2	47.9± 11.0***
Cigarette per day	20.7±8.9	24.8±6.2***
Cotinine (ng/ml): Scr	1,262±722	1,566±989
V1	1,378±722	1,772±1,107
V3	1,451 ±823	1,779±1,011
FEV1 (L)a	3.8±0.8	2.2±0.4***
FEV1% predicteda	112.5±14.1	66.1±7.2***
FEV1/FVC (%)a	75.4±5.0	50.0±8.7***
Wpeak (W)	154.8±35.1	110.9±23.9***
PaO2	82.9±9.7	73.5±5.4
PaCO2	41.6±2.0	41.3±2.5

Notes: Values are presented as mean ± SD, except for age where we report median (Min, Max);

* P<0.05,

** P<0.01,

*** P<0.001. W_peak means peak exercise level that could be maintained for 30 seconds (during an escalation scheme with a stepwise increase in the work rate by 10 W every minute.

a Data of COPD patients was assessed post bronchodilator treatment. PaO₂, PaCO₂ stand for partial pressure of O₂ and CO₂ derived from the blood gas analysis.

Abbreviations: COPD, chronic obstructive pulmonary disease; BMI, body mass index; Scr, screening; V, visit; SD, standard deviation; Min, minimum; Max, maximum; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity.

Figure 1 Study design.

Notes: The TP1 and TP2 were fixed, while constant-load exercise was performed until the subject was exhausted; TP3 was therefore different between individuals (maximum 30 minutes). The period of rest was always 20 minutes following the end of exercise.
Abbreviations: TP, time points; Max, maximum; min, minutes; V, visit; d, day.

Figure 2 Individual constant-load exercise level for COPD smokers (Y) and for healthy smokers (N).

Notes: Median levels and interquartile ranges are presented. ***P<0.001.
Abbreviation: COPD, chronic obstructive pulmonary disease.

Figure 3 Individual time points until the exercise challenge was terminated due to exhaustion.

Notes: (Left) COPD smokers. (Right) Healthy smokers. Both axes display the absolute duration of exercise. The enlarged open dot (COPD smoker) represents two data points, and the enlarged closed dot (healthy smoker) represents six data points. Median and interquartile ranges are displayed.

Abbreviations: COPD, chronic obstructive pulmonary disease; min, minutes.

Figure 4 Time course for the peripheral blood concentrations of lactate, separately for COPD smokers (open symbols) and healthy smokers (closed symbols).

Notes: The results of visit 1 are displayed on the left (n=23/23); the results of the repeated visit (28±5 days later, n=20/19) are displayed on the right. Blood was drawn before (displayed at 0 minutes), after 5 minutes of exercise (displayed at 5 minutes), at the time of exhaustion or a maximum duration of 30 minutes exercise, and following a period of 20 minutes of rest (both displayed at the median duration for each group). Median levels and interquartile ranges are presented. There were no differences between COPD smokers and healthy smokers at the different time points.

Abbreviations: COPD, chronic obstructive pulmonary disease; min, minutes.

Figure 5 Time course for the peripheral blood concentrations of IL6, MPO, and CRP, separately for COPD smokers (open symbols) and healthy smokers (closed symbols).

Notes: For more details, refer to the legend of Figure 4. Median levels and interquartile ranges are presented. ***P<0.001, **P<0.01, *P<0.05.

Abbreviations: IL6, interleukin 6; MPO, myeloperoxidase; CRP, C-reactive protein; COPD, chronic obstructive pulmonary disease; min, minute; V, visit.

Figure 6 Time course for the peripheral blood concentrations of sVCAM1, sICAM1, VWF, and LTB4 separately for COPD smokers (open symbols) and healthy smokers (closed symbols).

Notes: For more details, refer to the legend of Figure 4. Median levels and interquartile ranges are presented. ***P<0.001, **P<0.01, *P<0.05.
Abbreviations: sVCAM1, soluble vascular cell adhesion molecule 1; sICAM1, soluble intercellular adhesion molecule 1; VWF, von Willebrand factor; LTB4, leukotriene B4; COPD, chronic obstructive pulmonary disease; min, minute; V, visit.