Reduced Appendicular Lean Body Mass, Muscle Strength, and Size of Type II Muscle Fibers in Patients with Spondyloarthritis versus Healthy Controls: A Cross-Sectional Study
Table 3
Muscle morphology: parameters obtained from biopsy of m. vastus lateralis.
Variable
Patients
Controls
(95% CI lower; upper)
Muscle fiber distribution
Type I, %
54.9 ± 13.8 (33.6–76.8)
48.5 ± 11.4 (30.5–68.3)
0.32 (−7.5; 20.5)
Type II, %
45.1 ± 13.8 (23.2–66.4)
51.5 ± 11.4 (31.7–69.5)
0.34 (−4.2; 10.8)
Ratio CSA type II/type I
1.05 ± 0.17 (0.83–1.37)
1.27 ± 0.22 (0.95–1.94)
0.05 (−0.442; −0.002)
Myonuclei
Type I, pr. fiber
3.6 ± 1.1 (2.2–6.0)
3.8 ± 0.6 (3.1–4.8)
0.65 (−0.96; 0.63)
Type II, pr. fiber
4.0 ± 1.1 (2.6–6.0)
4.6 ± 1.0 (3.2–6.5)
0.25 (−1.75; 0.51)
Central nuclei
Type I, pr. fiber
0.02 ± 0.03 (0.00–0.10)
0.08 ± 0.14 (0.00–0.44)
0.20
Type II, pr. fiber
0.03 ± 0.03 (0.00–0.08)
0.08 ± 0.11 (0.00–0.32)
0.26
Satellite cells, Pax7-positive
Type I, pr. 100 fibers
8.8 ± 8.0 (1.5–29.7)
6.4 ± 4.2 (1.6–17.1)
0.62 (−0.61; 0.97)
Type II, pr. 100 fibers
5.5 ± 2.7 (2.6–11.3)
8.0 ± 6.0 (3.4–24.3)
0.13 (−0.76; 0.12)
Values are mean ± SD (range) unless otherwise indicated. Wilcoxon signed ranks test. Log-transformed variable, paired samples -test. CD68: marker for macrophages. CD66b: marker for neutrophils. CSA: cross-sectional area. ECM: extracellular matrix. Comparison between groups tested by paired samples -test unless otherwise indicated.
