BackgroundScleroderma is an autoimmune disease with a characteristic vascular pathology. The vasculopathy associated with scleroderma is one of the major contributors to the clinical manifestations of the disease.Methodology/Principal FindingsWe used immunohistochemical and mRNA in situ hybridization techniques to characterize this vasculopathy and showed with morphometry that scleroderma has true capillary rarefaction. We compared skin biopsies from 23 scleroderma patients and 24 normal controls and 7 scleroderma patients who had undergone high dose immunosuppressive therapy followed by autologous hematopoietic cell transplant. Along with the loss of capillaries there was a dramatic change in endothelial phenotype in the residual vessels. The molecules defining this phenotype are: vascular endothelial cadherin, a supposedly universal endothelial marker required for tube formation (lost in the scleroderma tissue), antiangiogenic interferon α (overexpressed in the scleroderma dermis) and RGS5, a signaling molecule whose expression coincides with the end of branching morphogenesis during development and tumor angiogenesis (also overexpressed in scleroderma skin. Following high dose immunosuppressive therapy, patients experienced clinical improvement and 5 of the 7 patients with scleroderma had increased capillary counts. It was also observed in the same 5 patients, that the interferon α and vascular endothelial cadherin had returned to normal as other clinical signs in the skin regressed, and in all 7 patients, RGS5 had returned to normal.Conclusion/SignificanceThese data provide the first objective evidence for loss of vessels in scleroderma and show that this phenomenon is reversible. Coordinate changes in expression of three molecules already implicated in angiogenesis or anti-angiogenesis suggest that control of expression of these three molecules may be the underlying mechanism for at least the vascular component of this disease. Since rarefaction has been little studied, these data may have implications for other diseases characterized by loss of capillaries including hypertension, congestive heart failure and scar formation.

Abstract-We performed a systematic analysis of gene expression in arteries and veins by comparing message profiles of macaque aorta and vena cava media using a cDNA array containing 4048 known human genes, Ϸ35% of currently named human genes (Ϸ11 000). The data show extensive differences in RNA expression in artery versus vein media. Sixty-eight genes had consistent elevation in message expression by the aorta, but none were elevated in the vena cava. The most differentially expressed gene was regulator of G-protein signaling (RGS) 5, at an expression ratio of 46.5Ϯ12.6 (meanϮSEM). The data set also contained 2 genes already known to be expressed in the aorta, elastin at 5.0Ϯ1.4, and the aortic preferentially expressed gene 1 (APEG-1) at 2.3Ϯ0.6. We chose to analyze RGS5 expression further because of its high level of differential expression in the aorta. Levels of RGS5 mRNA were confirmed by Northern analysis and in situ hybridization. A human tissue RNA dot blot showed that RGS5 message is highest in aorta, followed by small intestine, stomach, and then heart. Northern analysis confirmed that RGS5 expression in human aorta is higher than in any region of the heart. RGS5 is a G-protein signaling regulator of unknown specificity most homologous to RGS4, an inhibitory regulator of pressure-induced cardiac hypertrophy. The expression pattern of the 68 differential genes as a whole is a start toward identifying the molecular phenotypes of arteries and veins on a systematic basis. (Circ Res. 2000;87:623-631.)Key Words: cDNA array Ⅲ aorta Ⅲ vena cava Ⅲ expression profile Ⅲ RGS5 W e have begun a systematic analysis of expression differences between vascular smooth muscle tissues. We chose to begin with an analysis of the media of aorta and vena cava because of the possibility of isolating relatively homogenous cellular populations and because of the distinct functional requirements, embryological origins, and hemodynamic environments of these 2 tissues.The present study, using a cDNA array containing 35% of human named genes (4048 of the Ϸ10 900 functionally identified human genes in UniGene Build No. 109 of the National Center for Biotechnology Information human Unigene collection), identified 68 genes that are consistently expressed at higher levels in the aorta. No genes were more consistently highly expressed by the vena cava. One of these aortic markers, regulator of G-protein signaling (RGS) 5, showed extreme levels of differential expression. Together, these genes offer a molecular definition of the phenotypes of these 2 types of smooth muscle. Materials and Methods Array HybridizationResearch Genetics GF211 cDNA arrays (4048 human genes) were used as specified. Equivalent amounts of RNA per vessel pair were used to synthesize cDNA probes, and equivalent counts per minute were added to hybridizations. Washed blots were exposed to phosphor image screens and scanned on a Storm phosphor imager (Molecular Dynamics). Expression was quantified from scans with similar intensity and background, using Pathways software ...