Background-Immune responses participate in several phases of atherosclerosis; there is, in fact, increasing evidence that both adaptive immunity and innate immunity tightly regulate atherogenesis. Pentraxins are a superfamily of acute-phase proteins that includes short pentraxins such as C-reactive protein or long pentraxins such as PTX3, a molecule acting as the humoral arm of innate immunity. To address the potential role of PTX3 in atherogenesis, we first investigated the expression of PTX3 during atherogenesis, generated double-knockout mice lacking PTX3 and apolipoprotein E, and then studied the effect of murine PTX3 deficiency on plasma lipids, atherosclerosis development, and gene expression pattern in the vascular wall. Methods and Results-PTX3 expression increases in the vascular wall of apolipoprotein E-knockout mice from 3 up to 18 months of age. Double-knockout mice lacking PTX3 and apolipoprotein E were fed an atherogenic diet for 16 weeks. Aortic lesions were significantly increased in double-knockout mice and mice heterozygous for PTX3 compared with apolipoprotein E-knockout mice. Mice lacking PTX3 showed a more pronounced inflammatory profile in the vascular wall as detected by cDNA microarray and quantitative polymerase chain reaction analysis and an increased macrophage accumulation within the plaque. Finally, lesion size correlated with the number of bone marrow monocytes. Conclusion-PTX3 has atheroprotective effects in mice, which, in light of the cardioprotective effects recently reported, suggests a cardiovascular protective function of the long pentraxin 3 through the modulation of the immunoinflammatory balance in the cardiovascular system. (Circulation. 2009;120:699-708.)

Heat shock protein 27 (HSP27) is traditionally viewed as an intracellular chaperone protein with anti-apoptotic properties. However, recent data indicate that a number of heat shock proteins, including HSP27, are also found in the extracellular space where they may signal via membrane receptors to alter gene transcription and cellular function. Therefore, there is increasing interest in better understanding how HSP27 is released from cells, its levels and composition in the extracellular space, and the cognate cell membrane receptors involved in effecting cell signaling. In this paper, the knowledge to date, as well as some emerging paradigms about the extracellular function of HSP27 is presented. Of particular interest is the role of HSP27 in attenuating atherogenesis by modifying lipid uptake and inflammation in the plaque. Moreover, the abundance of HSP27 in serum is an emerging new biomarker for ischemic events. Finally, HSP27 replacement therapy may represent a novel therapeutic opportunity for chronic inflammatory disorders, such as atherosclerosis.