Proteasome activity related with the daily physical activity of COPD patients

Figures & data

Table 1 Characteristics of the 57 participants

Variables	Healthy subjects (n=15)	COPD patients (n=42)	P-value
Age (years), mean ± SD	64.10±11.7	67.1±6.5	0.113
Gender (M/F)	12/3	39/3	0.180
Smoker			0.465
Nonsmoker (%)	11 (73.3)	3 (7.2)
Current smoker (%)	4 (26.7)	9 (21.4)
Ex-smoker (%)	0	30 (71.4)
Anthropometric indicators, mean ± SD
BMI (kg/m^2)	22.8±3.0	24.5±3.4	0.0908
MAC (cm)	26.6±4.2	27.3±3.1	0.9566
CC (cm)	35.5±2.9	33.1±5.8	0.8111
FFMI (kg/m^2)	19.5±6.3	18.0±0.3	0.1718
Pulmonary function tests, mean ± SD
FEV1 (L/min)	2.37±0.53	1.01±0.46	<0.0001
FEV1 (% predicted)a	88.3±7.8	40.5±16.5	<0.0001
FVC (L/min)	2.99±0.66	2.05±0.62	<0.0001
FVC (% predicted)	89.5±10.2	63.1±16.6	<0.0001
FEV1/FVC (%)	80.8±5.6	48.7±11.0	<0.0001
6MWD (meter)	535.1±14.2	416.3±11.7	<0.0001
DPA (counts/min)	213.1±8.1	154.4±3.8	<0.0001
Protein carbonyl	4.7±1.1	9.9±5.4	0.0065
Proteasome activities	0.3±0.2	1.1±0.9	0.0051

Notes:

a According to FEV₁ values, 12 (28.6%) subjects had very severe (FEV₁ <30%), 18 (42.8%) subjects had severe (50%< FEV₁ ≤30%), and 12 (28.6%) subjects had mild to moderate COPD (FEV₁ ≥50%).

Abbreviations: 6MWD, 6 min walking distance; BMI, body mass index; CC, calf circumference; DPA, daily physical activity; FEV₁, forced expiratory volume in the first second; FFMI, fat-free mass index; FVC, forced vital capacity; MAC, mid-arm circumference.

Figure 1 (A) 6MWD during the 6MWT in healthy subjects and COPD patients. (B) Delta SpO₂ during the 6MWT in healthy subjects and COPD patients. (C) DPA in healthy subjects and COPD patients. (D) Delta SpO₂ during DPA in healthy subjects and COPD patients. **P<0.01 between groups.

Abbreviations: 6MWD, 6 min walking distance; 6MWT, 6 min walking test; DPA, daily physical activity; HS, healthy subject; SpO₂, saturation of pulse oxygenation.

Figure 2 Time spent in each of the activities or body positions in healthy subjects and COPD patients during the entire day.

Note: **P<0.01 between groups.

Figure 3 (A) Serum protein carbonyl levels in healthy subjects and subjects with COPD. (B) IL-6 levels in healthy subjects and COPD patients. (C) Serum TNF-α levels in healthy subjects and COPD patients. (D) Serum proteasome activity in healthy subjects and COPD patients. (E) Serum ubiquitin levels in healthy subjects and COPD patients. **P<0.01 between groups.

Abbreviations: HS, healthy subject; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α.

Table 2 Pearson’s correlation coefficients (r) of proteasome activity, protein carbonyl, and functional physical activity in subjects

Indicator	Proteasome activity			Protein carbonyl
	Total subjects	HSs	COPD	Total subjects	HSs	COPD
Anthropometric indicator
BMI (kg/m^2)	0.256	0.573	0.212	−0.223	−0.605	−0.318*
MAC (cm)	0.004	0.032	−0.012	−0.323*	−0.270	−0.350*
CC (cm)	0.156	−0.595	0.070	−0.340*	−0.414	−0.322*
FFMI (kg/m^2)	0.038	0.479	0.050	−0.227	0.074	−0.309
FEV1 (% predicted)	−0.235	−0.191	0.079	−0.526**	0.582	−0.441**
Functional physical activity
DPA (counts/min)a	−0.529*	0.264	−0.568*	0.089	0.310	0.114
Delta SpO2 (%/day)b	−0.350	−0.312	−0.131	−0.063	−0.098	0.208
6MWD (m)	−0.200	−0.339	−0.067	−0.439*	0.338	−0.313*
Delta SpO2 (%)	0.041	0.685	0.186	−0.054	0.042	0.130
Protein carbonyl (nmol/mg)	0.098	−0.459	0.016	–	–	–

Notes:

a According to DPA subjects (11 HSs and 16 COPD patients);

b according to the delta SpO₂ subjects (11 HSs and 16 COPD patients);

* P<0.05,

** P<0.01.

Abbreviations: 6MWD, 6 min walking distance; BMI, body mass index; CC, calf circumference; DPA, daily physical activity; FEV₁, forced expiratory volume in the first second; FFMI, fat-free mass index; HSs, healthy subjects; MAC, mid-arm circumference; SpO₂, saturation of pulse oxygenation.