Essential PTX3 Biology (not only) for Cardiologists and Cardiac Surgeons

New Insights on the Role of pentraxin-3 in Allergic Asthma

Pentraxins are soluble pattern recognition receptors that play a major role in regulating innate immune responses. Through their interaction with complement components, Fcγ receptors, and different microbial moieties, Pentraxins cause an amplification of the inflammatory response. Pentraxin-3 is of particular interest since it was identified as a biomarker for several immune-pathological diseases. In allergic asthma, pentraxin-3 is produced by immune and structural cells and is up-regulated by pro-asthmatic cytokines such as TNFα and IL-1β. Strikingly, some recent experimental evidence demonstrated a protective role of pentraxin-3 in chronic airway inflammatory diseases such as allergic asthma. Indeed, reduced pentraxin-3 levels have been associated with neutrophilic inflammation, Th17 immune response, insensitivity to standard therapeutics and a severe form of the disease. In this review, we will summarize the current knowledge of the role of pentraxin-3 in innate immune response and discuss the protective role of pentraxin-3 in allergic asthma.

Long-term prognostic utility of pentraxin 3 and D-dimer as compared to high-sensitivity C-reactive protein and B-type natriuretic peptide in suspected acute coronary syndrome

BACKGROUND

Vascular inflammation plays a key role in the development of atherosclerosis and acute coronary syndrome (ACS), and pentraxin 3 (PTX3) is one of several novel, promising markers of inflammation. In addition, D-dimer might serve as a marker of thrombogenesis and a hypercoagulable state following plaque rupture. The present study assesses the prognostic utility of these two biomarkers as compared to high-sensitivity C-reactive protein (hsCRP) and B-type natriuretic peptide (BNP), in addition to conventional clinical risk factors for coronary heart disease in patients with suspected ACS.

METHODS

Chest pain patients with suspected ACS (n = 871) were consecutively included in a prospective, observational study with a follow-up time of 84 months.

RESULTS

At 7-year follow-up, 332 patients had died and 203 had suffered an adverse troponin T-positive, non-fatal cardiac event. In the multivariate analysis, levels of PTX3 above 5.88 ng/mL (median) and D-dimer above 436 µg/L (lower limit upper quartile) independently predicted mortality (HR 1.60 [95% CI 1.10-2.33]; p = 0.014 and HR 1.83 [95% CI 1.20-2.78]; p = 0.005, respectively). Also, BNP levels above 310.75 pg/mL (lower limit upper quartile) (HR 2.16 [95% CI 1.37-3.42]; p = 0.001), but not hsCRP, independently predicted mortality. Only hsCRP and BNP also predicted future myocardial infarction (HR 1.59 [95% CI 1.05-2.40]; p = 0.029 and HR 1.91 [95% CI 1.10-3.31]; p = 0.021, respectively).

CONCLUSION

High levels of PTX3, D-dimer and BNP were found to be independent, long-term predictors of all-cause mortality in chest pain patients with a suspected ACS. hsCRP and BNP also predicted future myocardial infarction.

Long pentraxin 3 (PTX3) in the light of its structure, mechanism of action and clinical implications

Pentraxins are a group of evolutionarily conserved ancient proteins. Depending on their structure, pentraxins are divided into short and long pentraxin families. Pentraxin 3 (PTX3) is the prototype of the long pentraxin group. PTX3 synthesis is stimulated by a variety of molecules involved in the inflammatory process. The inflammatory mediator is typically produced at inflammatory sites; however, it can also be released at the sites remote from the original inflammatory insult. Although mainly expressed by vascular endothelium and smooth muscle cells, PTX3 is also synthesized by myeloid dendritic cells, mononuclear macrophages/phagocytes, vascular endothelial and smooth muscle cells, fibroblasts, adipocytes, cumulus oophorus cells mesangial cells, synovial cells and chondrocytes. PTX3 binds to several ligands including complement component C1q, factor H, ficolin-1 (M-ficolin), mannose-binding lectin, fibroblast growth factor 2, P-selectin, matrix protein TSG6 and Klebsiella pneumoniae; it is also known to play a role in humoral innate immunity as well as in degenerated and apoptotic cells clearance. PTX3 acts as a modulator of inflammatory processes, modifies angiogenesis and atherosclerotic lesion development, and participates in extracellular matrix formation. Due to the fact of PTX3 being primarily produced and released by vascular wall cells, it might be used as a sensitive and independent inflammatory marker.