Response to Polymorphisms of Inflammatory Markers/Mediators and Arterial Stiffness
We thank Vlachopoulos et al1 for their comments on our study investigating the relationship among circulating C-reactive protein (CRP) levels, CRP genotypes, and arterial stiffness. The positive association between circulating CRP levels and aortic pulse wave velocity in the Caerphilly Study confirms our previous observations in a younger population of healthy individuals2 in the ACCT cohort. Moreover, like Vlachopoulos et al,1 we have also demonstrated a positive association between interleukin 6 and arterial stiffness,3 which was not unexpected given that interleukin 6 is one of the major cytokines driving hepatic synthesis of CRP.
As we stated, the lack of association between CRP genotype and aortic pulse wave velocity indicates that CRP itself is unlikely to play a causal role in arterial stiffening. This view is substantiated by a large meta-analysis, not cited by Vlachopoulos et al,1 in which there was no relationship between CRP polymorphisms and cardiovascular outcome.4 Therefore, we believe that either serum CRP levels are a marker of other factors that promote arterial stiffening, eg, atheroma, or that arterial stiffening leads to elevated CRP levels. Nevertheless, we would agree that a better understanding of the pathophysiology of arterial stiffening remains crucial to future therapeutic strategies aimed at reducing cardiovascular events, especially in conditions characterized by increased arterial stiffening, eg, isolated systolic hypertension, and those associated with premature vascular ageing, eg, diabetes mellitus. The intriguing observations reported by Vlachopoulos et al1 must be treated with caution, because past experience suggests that such findings are often weaker or not at all replicated by subsequent research.5
Vlachopoulos C, Terentes-Printzios D, Dima I, Aznaouridis K, Stefanadis C. Polymorphisms of inflammatory markers/mediators and arterial stiffness. Hypertension. 2009; 53: e39.
Yasmin, McEniery CM, Wallace S, Mackenzie IS, Cockcroft JR, Wilkinson IB. C-reactive protein is associated with arterial stiffness in apparently healthy individuals. Arterioscler Thromb Vasc Biol. 2004; 24: 969–974.
Shah T, Casas JP, Cooper JA, Tzoulaki I, Sofat R, McCormack V, Smeeth L, Deanfield JE, Lowe GD, Rumley A, Fowkes FGR, Humphries SE, Hingorani AD. Critical appraisal of CRP measurements for the prediction of coronary heart disease events: new data and systematic review of 31 prospective cohorts. Int J Epidemiol. 2009; 38: 217–231.