Endothelial cell dysfunction and elevated C reactive protein (CRP) are key risk factors
associated with a high incidence of premature cardiovascular disease (CVD) and early
mortality in patients with rheumatoid arthritis (RA). Having already demonstrated
an anti-arthritic effect of turmeric extracts in an animal model of RA (streptococcal
cell wall [SCW]-induced arthritis)[1,2], studies were undertaken to determine whether
turmeric also lowers CVD risk in RA. To this end, [1] the in vitro ability of well-characterized turmeric extracts to prevent pro-atherogenic changes
in the expression of key genes responsible for decreased vasodilation, increased leukocyte
adhesion, and increased thrombosis in the RA vasculature was assessed in TNF-activated
human umbilical vascular endothelial cells (HUVEC) using real time RT PCR, and [2]
the in vivo effect of these same extracts on elevated serum levels of CRP was determined by ELISA
in the SCW-induced arthritis model of RA. An essential oil-free fraction containing
41% by weight of the 3 major curcuminoids, a purified curcuminoid-only fraction (95%)
and an essential oil-only fraction were compared. In HUVEC, both curcuminoid-containing
samples inhibited TNF-stimulated expression of [1] the adhesion factors, E-selectin,
ICAM and VCAM, and [2] tissue factor, a protein that initiates one arm of the coagulation
cascade, while having no effect on expression of eNOS or thrombomodulin. The essential
oil only fraction of turmeric had no effect on HUVEC gene expression. In complete
contrast, serum levels of CRP were reduced by the essential oil fraction of turmeric
in SCW-induced arthritis, while the curcuminoid-containing samples were without effect.
In conclusion, these results suggest that turmeric may be cardioprotective in RA and
that its various components (polyphenols vs. essential oils) may act by targeting
different pathways.
References: 1. Funk, JL. et al (2006)J Nat Prod 69:351.
2. Funk, JL. et al (2006) Arth Rheum 54:3452.
