Thesis Abstracts 1994

Because the current assessment of scleroderma skin through clinical skin scoring is subjective and imprecise, we investigated fully quantitative, physical measures of cutaneous involvement in the disease. First, we developed image analysis software for calculating the dermal density of colla-gen from 58 scleroderma and 327 control biopsies scanned onto our computer. Second, using a durometer gauge, we obtained measurements of skin hardness over 12 prespecified body regions for 13 scleroderma patients and 100 controls; we also obtained ultrasonic measurements of skin thickness for the same 13 scleroderma patients and four controls. At 2 cm intervals over the dorsal and ventral arms of four scleroderma patients, we obtained serial durom-eter and ultrasound measurements, correlating them with independent and blinded assessments of skin score at each point. Third, we acquired two-dimensional laser Doppler maps of cutaneous blood flow over the dorsal hands of 10 scleroderma patients and 16 controls. We developed software to abstract mean blood flow, arteriolar islands and avascular areas from the images. Finally, with continuous laser Doppler point measurement of blood flow, we assessed the hyperemic response to occlusion in eight scleroderma hands, three scleroderma forearms and 15 controls (both sites). Average dermal collagen density was significantly higher in scleroderma at 88.5 + 6.9 percent, compared with 75 + 9.3 percent in controls (p < .001). Durometer measurements were significantly greater for scleroderma patients (p < .05) over the finger, hand, wrist, forearm and ventral arm, although differences in ultrasonic thickness did not reach significance. While skin scores of 0 and 1 were associated with significantly different (p < .05) durometer readings in all four patients, the durometer fared less well in distinguishing among more severe degrees of sclerosis where skin thickness showed the greatest differences. In sclero-derma, mean blood flow at 483.2 + 421.2 mV and arteriolar island density at 1.4 + 0.5 /cm2 were significantly greater than the control averages of 276.3 + 146.3 mV and 1.0 + 0.5 /cm2, respectively (p < .05). We did not detect any abnormalities in reflex hyperemic response in scleroderma. Dermal collagen density and durometer measurements of skin hardness accurately quantify skin sclerosis in scleroderma. Moreover, increased cutaneous blood flow and greater use of microvascular reserve reflect defects in vascular regulation inherent to the disease. These reproducible, physical measurements will allow us to more precisely monitor the progression of scleroderma and evaluate its response to experimental treatments. Synaptic circuits of the …