Alterations in the muscle-to-capillary interface in patients with different degrees of chronic obstructive pulmonary disease

Table 2 Fibre type distribution, fibre area, fibre perimeter, CAF and CAFA for type I and type IIa fibres.

	Healthy subjects (n = 12)	Mild COPD (n = 8)	Moderate COPD (n = 9)	Severe COPD (n = 6)	P-value
Proportion type I fibres (%)	78.3 ± 8.7	70.2 ± 11.4	74.5 ± 11.9	59.4 ± 9.5*	0.009
Proportion type IIa fibres (%)	20.2 ± 8.9	24.6 ± 10.6	22.6 ± 11.4	40.2 ± 7.6*	0.02
Proportion type IIx fibres (%)	0	1.0 ± 1.6	0.6 ± 1.1	1.2 ± 2.1	ns
Proportion type IIx-a fibres (%)	0	0.2 ± 0.3	0.3 ± 0.6	0.5 ± 0.7	ns
Proportion type I-IIa fibres (%)	1.5 ± 1.4	4.0 ± 6.4	2.0 ± 2.3	1.6 ± 1.4	ns
Perimeter type I fibres	330 ± 38	332 ± 60	295 ± 40	320 ± 87	ns
Perimeter type IIa fibres	380 ± 48	348 ± 56	274 ± 53*	303 ± 81	0,003
Area type I fibres (μm²)	7143 ± 1508	7315 ± 2471	5736 ± 1497	6557 ± 2901	ns
Area type IIa fibres (μm²)	9262 ± 2215	7711 ± 2427	4880 ± 1970*	5418 ± 2232	0,004
CAF type I fibres (μm)	6,8 ± 1,1	6,8 ± 2,6	5,2 ± 0,9*	5,1 ± 1,2*	0,006
CAF type IIa fibres (μm)	6,7 ± 1,9	6,3 ± 2,4	4,4 ± 0,8*	4,5 ± 1,0*	0,002
CAFA type I fibres	1,0 ± 0,1	1,1 ± 0,4	1,0 ± 0,3	0,9 ± 0,2	ns
CAFA type IIa fibres	0,8 ± 0,3	1,0 ± 0,3	1,1 ± 0,3	1,0 ± 0,3	ns

Data are presented as mean ± SD.
*Significant difference compared to healthy subjects.
n = number of test subjects; CAF = number of capillaries around a single fibre; CAFA = the ratio between CAF and the area of the muscle fibre; ns = not significant

ISSN: 1465-993X