Systematic Review of the Role of Microparticles in Systemic Sclerosis

Abstract

Microparticles (MPs) are small, membrane-coated vesicles released in response to injury, cell activation or apoptosis. Growing evidence suggests associations between MPs and disease manifestations in systemic sclerosis (SSc). The aim of this study is to systematically review published articles and abstracts that discuss the role of MPs in SSc. The Web of Science(®), PubMed(®) and Google Scholar databases were searched for all articles and abstracts that discussed MPs in the context of SSc. The literature search was conducted on 18 July 2013 and restricted to English-language articles and abstracts. From a total of 150 distinct articles and 10 abstracts, only 14 articles and 4 abstracts met the criteria for an attempt of quantitative synthesis. Twenty articles were accepted for a review of reviews. Conference proceedings and journals not cataloged in either Web of Science(®) or PubMed(®) or searchable by Google Scholar would have been undetected. There is a risk of valid studies with negative results going unpublished. Few studies have been conducted on MPs in patients with SSc so it was possible to thoroughly consider each. While there is low quality evidence from studies that plasma concentrations of circulating endothelial and platelet MPs are elevated in SSc patients and that plasma concentrations of circulating endothelial MPs are higher in SSc cases with either pulmonary hypertension or interstitial lung disease than those SSc cases without, definitive conclusions are not possible due to heterogeneity of the studies with respect to inclusion criteria, populations studied, laboratory analysis methods, and choice of outcome statistics.