RESEARCH - C-reactive protein: the underlying cause of microvascular dysfunction in RA

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Rheumatology Advance Access published online on October 14, 2008

Rheumatology, doi:10.1093/rheumatology/ken386

C-reactive protein: the underlying cause of microvascular dysfunction

in rheumatoid arthritis

B. Galarraga1, F. Khan1, P. Kumar1, T. Pullar1 and J. J. F. Belch1

1The Institute of Cardiovascular Research, Vascular and Inflammatory

Diseases Research Unit, University Division of Medicine and

Therapeutics, Ninewells Hospital and Medical School, Dundee, UK.

Abstract

Objective. RA is a chronic autoimmune inflammatory condition

associated with increased cardiovascular morbidity and mortality.

Endothelial dysfunction, a marker of early atherosclerotic disease,

occurs in some inflammatory diseases but this relationship has not

been previously explored within the microvasculature of patients with

RA. We therefore assessed forearm microvascular endothelial function

in patients with RA and determined its relationship to RA disease

activity and inflammation.

Methods. A total of 128 RA patients with no previous history of

cardiovascular disease were evaluated. Endothelium-dependent and

-independent forearm skin microvascular function was measured using

laser Doppler imaging after iontophoretic delivery of acetylcholine

(ACh) and sodium nitroprusside (SNP), respectively. Parameters of RA

disease activity and inflammation were also checked.

Results. There was a significant negative correlation between the

level of inflammation measured by log10CRP and maximum vasodilatation

measured by peak ACh response (r2 = ¨C0.209, P = 0.018, Pearson

correlation test). In a multiple regression model, age (¦Â = ¨C0.449, P

< 0.0001) and log10CRP (¦Â = ¨C0.193, P = 0.026) were independently

negatively associated with ACh responses. When RA patients were

sub-divided according to their systemic inflammatory status (CRP > 10

mg/l vs CRP 10 mg/l), the high CRP group showed lower vasodilator

responses to ACh [P = 0.018, analysis of variance (ANOVA)] and SNP (P

= 0.05, ANOVA) than the low CRP group.

Conclusions. In this large cross-sectional study, we found for the

first time systemic inflammation (CRP) to be independently associated

with microvascular dysfunction in patients with RA. This strong

correlation was independent of other conventional vascular risk

factors.

http://rheumatology.oxfordjournals.org/cgi/content/abstract/ken386v1?papetoc

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