C-reactive protein activates complement in infarcted human myocardium.
Circulating levels of C-reactive protein (CRP) constitute a cardiovascular risk marker. Immunohistochemical studies have revealed co-localization of CRP and activated complement in human infarcted myocardium suggesting CRP to enhance inflammation in ischemic myocardium by inducing local complement activation. The aim was to establish whether CRP activates complement in infarcted human myocardium and to assess the relationship between this activation and the duration of infarction. Myocardial tissue samples from 56 patients that had died from acute myocardial infarction were evaluated. Specimens were taken from infarcted as well as noninfarcted sites of the heart. CRP-mediated complement activation was assessed by immunohistochemistry and by measuring levels of complement, CRP, and CRP-complement complexes, specific markers for CRP-mediated activation, in homogenates of the heart. Infarctions of 12 hours to 5 days had significantly more extensive depositions of complement and CRP and contained significantly more CRP, activated complement, and CRP-complement complexes than infarctions that were less than 12 hours old. Levels of CRP complexes correlated significantly with CRP and complement concentrations in the infarctions, as well as with the extent of complement and CRP depositions as measured via immunohistochemistry. Specific activation products of CRP-mediated activation of complement are increased in infarcts of more than 12 hours in duration and correlate with the extent of complement depositions. Hence, CRP seems to enhance local inflammatory reactions ensuing in human myocardial infarcts of more than 12 hours duration.
Nijmeijer
Remco
R
Institute for Cardiovascular Research, Vrije Universiteit Medical Center, Amsterdam, The Netherlands.
Lagrand
Wim K
WK
Lubbers
Yvonne T P
YT
Visser
Cees A
CA
Meijer
Chris J L M
CJ
Niessen
Hans W M
HW
Hack
C Erik
CE
D002097:C-Reactive Protein / Q000378:metabolism*; D003167:Complement Activation / Q000502:physiology*; D003181:Complement C4 / Q000378:metabolism*; D015935:Complement C4b; D006801:Humans; D007150:Immunohistochemistry; D009203:Myocardial Infarction / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D010446:Peptide Fragments / Q000378:metabolism*; D013223:Statistics as Topic; D014020:Tissue Extracts / Q000378:metabolism
D003181:Complement C4; D010446:Peptide Fragments; D014020:Tissue Extracts; D015935:Complement C4b; C032261:complement C4d; D002097:C-Reactive Protein