Assessment of endothelial function, accumulation of advanced glycation end products and atherosclerosis in patients with longstanding Rheumatoid Arthritis

The mortality of patients with Rheumatoid Arthritis (RA) is, compared to the
general population increased mainly due to cardiovascular disease. This
premature atherosclerosis can not be explained by the presence of the
traditional cardiovascular risk factors. Additional, autoimmunity-related
non-traditional risk factors, have been suggested to contribute to the
development of atherosclerosis in these patients
Activation and dysfunction of endothelial cells (EC) are considered the first
steps in the atherosclerotic process.
Indeed, endothelial activation markers like vascular cell adhesion molecule-1
(VCAM-1), thrombomodulin (TM) and von Willebrand factor (vWF) are increased in
RA patients. As a result of EC activation and oxidative stress other events
occur, like the formation of advanced glycation endproducts (AGEs). AGEs are a
class of compounds resulting from glycation and oxidation of proteins, lipids
or nucleic acids. The accumulation of AGEs in the vessel wall has also been
related to the development of atherosclerosis
Endothelial function and the role of AGEs in the development of atherosclerosis
in RA are still poorly studied. As EC dysfunction informs about the earliest
stages of the atherosclerotic process it provides the opportunity to intervene
in this stage in order to prevent manifest cardiovascular disease
EC dysfunction can be detected by several techniques. Flow-mediated dilation,
measuring the response to reactive hyperemia, is most commonly used. Indeed,
impaired endothelium dependent vasodilatation was shown in young RA patients
without traditional cardiovascular risk factors or cardiovascular events.
However, the method has a poor reproducibility and informs about larger
vessels. EC dysfunction can also be detected non-invasively by pulse-wave
analysis (PWA), which measures large and small artery elasticity (LAE and SAE,
respectively) [24]. Unlike FMD, PWA is more readily available and
well-tolerated. Several studies have shown that PWA is a reproducible method to
assess EC function in vivo.
AGE accumulation can by measured by autofluorescence with the AutoFluorescence
Reader (AFR, patent PCT/NL99/00607) A tool for noninvasive assessment of AGE
accumulation in skin.
These two measuremnets will be related to the Intima Media Thickness a
surrogate marker for atherosclerosis.

We hypothesise that EC dysfunction, measured by PWA, will be present in
longstanding RA patients and that this EC dysfunction is related to EC
activation, AGE formation, and the presence of atherosclerosis. To analyse the
cause of EC dysfunction, we will investigate all traditional cardiovascular
risk factors as well as non-traditional, disease related, factors.
For this cross-sectional study RA patients with disease duration of 10-15 years
will be compared with age and sex matched healthy controls,

1. Is EC dysfunction, measured by PWA, present RA patients?
2. Is EC dysfunction in RA related to EC activation markers (CRP,
thrombomodulin, sVCAM, vWF), AGEs, and the presence of atherosclerosis?
3. Is EC dysfunction related to traditional cardiovascular risk factors or
non-traditional, disease related, factors such as cumulative markers of
inflammation and/or destruction?

For this cross sectional study we will approach 50 RA patients with a disease
duration of 10-15 years and 50 healthy age and sex matched controls (see power
analysis).
All participants will undergo PWA, IMT measurement by ultrasound, and
assessment of AGE accumulation using the AutoFluorescence Reader (AFR). Blood
will be taken for analysis and a questionnaire will be administrated. In total
this visit will take 1,5 hours.

All measurements, the complete visit will take about 1,5 hour. For the RA
patients we will try to combine this with a regular visit at the outpatient
clinic of the department of Rheumatology.

From RA patients 4 extra tubes of blood (26ml) will be drawn in addition to the
2 regular taken tubes for routine lab. controles at the out-patient clinic.
From the healthy controls a total of 6 tubes (34ml) will be collected for the
lab. measurements.
The other measurements (PWA, AGE-accumulation and IMT measurement) are
non-invasive.