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Department
of Dermatology (HJCdV, DNHE, JRM, JDB), and Department of Electron Microscopy
(JvM), Academic Medical Center, University of Amsterdam, and Department
of Plastic, Reconstructive and Hand Surgery (PPMvZ), Academic Medical Center,
University of Amsterdam, Amsterdam, and Burns Center, Red Cross Hospital,
Beverwijk, The Netherlands
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SUMMARY: Scleroderma, a chronic, progressive disorder, is characterized
by dermal fibrosis with collagen bundles orientated parallel to the epidermis.
Simple objective parameters to evaluate disease progression and therapies
are needed. We describe two methods, the laser scatter method and the
fast Fourier transform (FFT), to measure collagen bundle orientation and
spacing. Lesional sclerodermic skin (LS), nonlesional sclerodermic skin
(nonLS), and control skin (CS) sections were evaluated for orientation
ratio using the laser scatter method. The FFT was used to calculate orientation
ratio, variation, and spacing of collagen bundles. Parameters were correlated
with local and mean skin score measurements, on a scale of 0 (normal)
to 3 (severely sclerotic). With both the laser scatter method and the
FFT, orientation ratios of LS (respectively, 2.16± 0.33 and 1.83± 0.62)
were significantly higher than CS (respectively, 1.70± 0.35 and 1.38±
0.15). NonLS orientation ratios (respectively, 1.92± 0.15 and 1.48± 0.44)
were between LS and CS ratios. Orientation variation and bundle spacing
of LS (respectively, 57.3± 19.4 and 15.7± 5.6 um) were significantly reduced
compared to CS (respectively, 73.8± 15.0 and 18.9± 1.9 um). NonLS orientation
ratios (respectively, 57.2± 29.0 and 15.6± 6.1 um) were similar to LS.
Bundles in LS are more parallel, show less variation in orientation, and
are more densely packed than in CS. There was a linear correlation between
mean skin score and orientation ratio. Local skin score was not linearly
correlated to orientation ratio. Our findings suggest that nonLS dermis
without clinical sclerosis already shows fibrotic characteristics. Both
techniques were easy to use and suitable for objectifying dermal fibrosis
in scleroderma lesions. FFT is more accurate and reproducible than the
laser scatter method and allows simultaneous pathological evaluation of
the location of the analyzed tissue sections. Future studies will need
to focus on the correlation between clinical disease severity and collagen
bundle characteristics.
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