Selective apheresis of C-reactive protein: a new therapeutic option in myocardial infarction?

BACKGROUND: There is substantial evidence that C-reactive protein (CRP) mediates secondary damage of the myocardium after acute myocardial infarction (AMI). The aim of this animal trial in pigs was to specifically deplete CRP from porcine plasma after AMI and to study possible beneficial effects of the reduced CRP concentration on the infarcted area. METHODS: Ten pigs received balloon catheter-induced myocardial infarction. CRP was depleted from five animals utilizing a new specific CRP-adsorber, five animals served as controls. The area of infarction was analyzed by cardiovascular magnetic resonance imaging on day 1 and day 14 after AMI. Porcine CRP levels were determined by ELISA. RESULTS: CRP-apheresis resulted in a mean reduction of the CRP levels up to 48.3%. The area of infarction was significantly reduced by 30 ± 6% (P = 0.003) within 14 days in the treatment group, whereas it increased by 19 ± 11% (P = 0.260) in the controls. Fourteen days after infarction, the infarcted area revealed compact, transmural scars in the controls, whereas animals receiving CRP-apheresis showed spotted scar morphology. In the interventional group, a significantly higher left ventricular ejection fraction (LVEF) was observed after 14 days as compared to the controls (57.6 ± 2.4% vs. 46.4 ± 2.7%; P = 0.007). CONCLUSIONS: In a pig model for AMI, we observed that selective CRP-apheresis significantly reduces CRP levels and the volume of the infarction zone after AMI. Additionally, it changes the morphology of the scars and preserves cardiac output (LVEF).

Specific removal of C-reactive protein by apheresis in a porcine cardiac infarction model.

BACKGROUND: C-reactive protein (CRP) is a possible causative factor of the destructive processes observed during the weeks after myocardial infarction. METHODS: We developed a clinically relevant animal model including the removal of CRP from blood plasma utilizing a specific CRP adsorber and the visualization of the infarct scar in the living animal by cardiovascular magnetic resonance imaging as a tool to investigate the impact of CRP after acute myocardial infarction. RESULTS: We describe the facets of this model system and kinetics of clinical blood parameters like CRP and troponin. In addition, we demonstrate the potency of CRP apheresis reducing CRP levels by ~70% in the established treatment system. CONCLUSION: We showed for the first time that it is possible to conduct apheresis at the following 2 days after acute myocardial infarction in a porcine infarction model and to analyze the infarct by cardiovascular magnetic resonance imaging at day 1 and 14.

C-Reactive Protein Causes Blood Pressure Drop in Rabbits and Induces Intracellular Calcium Signaling.

Systemic diseases characterized by elevated levels of C-reactive protein (CRP), such as sepsis or systemic inflammatory response syndrome, are usually associated with hardly controllable haemodynamic instability. We therefore investigated whether CRP itself influences blood pressure and heart rate. Immediately after intravenous injection of purified human CRP (3.5 mg CRP/kg body weight) into anesthetized rabbits, blood pressure dropped critically in all animals, while control animals injected with bovine serum albumin showed no response. Heart rate did not change in either group. Approaching this impact on a cellular level, we investigated the effect of CRP in cell lines expressing adrenoceptors (CHO-α1A and DU-145). CRP caused a Ca2+ signaling being dependent on the CRP dose. After complete activation of the adrenoceptors by agonists, CRP caused additional intracellular Ca2+ mobilization. We assume that CRP interacts with hitherto unknown structures on the surface of vital cells and thus interferes with the desensitization of adrenoceptors.

CRP and SAP from different species have different membrane ligand specificities.

Human C-reactive protein (CRP) and serum amyloid component P (SAP) are well-characterised ligands for dying and dead cells, while facets of their physiological function still need to be unravelled. We partially characterised CRP and SAP from different species with similar acute-phase systems. Human, rabbit and porcine CRP bound phosphocholine (PC) and phosphoethanolamine (PEt). Human and porcine SAP bound PEt while rabbits seem to have very low levels of SAP or rabbit SAP does not bind PEt. Porcine serum additionally contained other ligands for PC and PEt. Some of them were immunoglobulins. Therefore, rabbits, pigs and humans cover the ability to bind PC and PEt with different extents.