scholarly journals Myocardial ischemia and reperfusion injury is dependent on both IgM and mannose-binding lectin

2009 ◽  
Vol 297 (5) ◽  
pp. H1853-H1859 ◽  
Author(s):  
Marc N. Busche ◽  
Vasile Pavlov ◽  
Kazue Takahashi ◽  
Gregory L. Stahl
Keyword(s):  
Myocardial Ischemia ◽  
Complement Activation ◽  
Tissue Injury ◽  
Left Ventricular ◽  
Mannose Binding Lectin ◽  
Left Ventricular Ejection ◽  
Ischemia And Reperfusion ◽  
Myocardial Ischemia And Reperfusion ◽  
Mannose Binding ◽  
Binding Lectin

Complement activation has been shown to play an important role in the inflammation and tissue injury following myocardial ischemia and reperfusion (MI/R). Several recent studies from our laboratory demonstrated the importance of mannose-binding lectin (MBL) as the initiation pathway for complement activation and the resulting pathological effects following MI/R. However, other studies from the past suggest an important role of the classical pathway and perhaps natural antibodies. In the present study, we used newly generated genetically modified mice that lack secreted IgM (sIgM), MBL-A, and MBL-C (sIgM/MBL null) in a plasma reconstitution mouse model of MI/R. Following 30 min of ischemia and 4 h of reperfusion, left ventricular ejection fractions were significantly higher in sIgM/MBL null mice reconstituted with MBL null or sIgM/MBL null plasma compared with reconstitution with wild-type (WT) plasma or WT mice reconstituted with WT plasma following MI/R. Serum troponin I concentration, myocardial polymorphonuclear leukocyte infiltration, and C3 deposition were dependent on the combined presence of sIgM and MBL. These results demonstrate that MI/R-induced complement activation, inflammation, and subsequent tissue injury require both IgM and MBL. Thus MBL-dependent activation of the lectin pathway may not be completely antibody independent in I/R models.

Sulfhydryl compounds, captopril, and MPG inhibit complement-mediated myocardial injury

1994 ◽  
Vol 266 (1) ◽  
pp. H28-H35 ◽  
Author(s):  
K. S. Kilgore ◽  
J. W. Homeister ◽  
P. S. Satoh ◽  
B. R. Lucchesi
Keyword(s):  
Complement Activation ◽  
Diastolic Pressure ◽  
Tissue Injury ◽  
Left Ventricular ◽  
Antioxidant Compounds ◽  
Ischemia And Reperfusion ◽  
Dependent Manner ◽  
Myocardial Ischemia And Reperfusion ◽  
Arterial Perfusion ◽  
Sulfhydryl Compounds

Factors including complement activation, neutrophil infiltration, and oxygen-derived free radicals have been implicated in the pathogenesis of myocardial tissue injury during ischemia and reperfusion. Certain sulfhydryl-containing compounds have been shown to inhibit complement activation. The sulfhydryl compounds captopril and N-(2-mercaptopropionyl)-glycine (MPG) are antioxidant compounds that previously have been shown to protect the myocardium from ischemia and reperfusion-induced damage. In this study, captopril (an angiotensin-converting-enzyme inhibitor; ACEI) and MPG, and the non-sulfhydryl compound enalaprilat (also an ACEI) were tested for their ability to protect the isolated perfused rabbit heart against complement-induced injury. Both captopril and MPG protected hearts against complement-mediated increases in left ventricular end-diastolic pressure and increases in coronary arterial perfusion pressure in a concentration-dependent manner, whereas enalaprilat was not protective. The ability of these compounds to inhibit complement activation also was tested using an in vitro complement-mediated red blood cell hemolysis assay. These findings offer additional insight as to the mechanism whereby captopril, MPG, and possibly other sulfhydryl compounds, may be acting to provide cytoprotection during myocardial ischemia and reperfusion.

Endogenous endothelin-1 impairs endothelium-dependent relaxation after myocardial ischemia and reperfusion

1994 ◽  
Vol 267 (5) ◽  
pp. H1833-H1841 ◽  
Author(s):  
J. M. Hagar
Keyword(s):  
Myocardial Ischemia ◽  
Control Release ◽  
Microvascular Dysfunction ◽  
Coronary Perfusion Pressure ◽  
Left Ventricular ◽  
Coronary Perfusion ◽  
Ischemia And Reperfusion ◽  
Myocardial Ischemia And Reperfusion ◽  
Developed Pressure ◽  
Eta Receptor Antagonist

Endothelin (ET)-1 is produced in response to myocardial ischemia and reperfusion. It is a potent constrictor of coronary resistance vessels and may therefore contribute to myocardial injury and postischemic microvascular dysfunction. Isolated buffer-perfused rabbit hearts, under conditions of constant flow and isovolumic contraction, underwent 60 min of global ischemia and 60 min of reperfusion after pretreatment with selective ETA receptor antagonist BQ-123 (10(-7) M) in perfusate, exogenous ET-1 (10(-11) M), or control. Release of ET increased significantly at 20 and 60 min of reperfusion. BQ-123 did not enhance the recovery of left ventricular developed pressure or coronary perfusion pressure, whereas exogenous ET tended to worsen them. Cumulative creatine kinase release over 20 min of reperfusion did not differ significantly between groups. Maximum endothelium-dependent dilation to acetylcholine (ACh) was initially 62 +/- 6, 71 +/- 6, and 63 +/- 8% (SE) of U-46619-induced preconstriction in control, BQ-123-, and ET-treated hearts. At 20 min of reperfusion it was 37 +/- 5, 73 +/- 9, and 22 +/- 5%, and at 60 min of reperfusion it was 35 +/- 7, 79 +/- 6, and 22 +/- 3% (P < 0.001 for BQ-123 vs. control at 20 min and P < 0.0001 at 60 min). Endothelium-independent dilation to nitroglycerin was unaltered by ischemia and reperfusion. Neither BQ-123 alone nor a 1-h infusion of ET (10(-10) M) altered the response to ACh in nonischemic hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Mannose-Binding Lectin is Associated with Thrombosis and Coagulopathy in Critically Ill COVID-19 Patients

2020 ◽  
Vol 120 (12) ◽  
pp. 1720-1724 ◽  
Author(s):  
Michael Hultström ◽  
Robert Frithiof ◽  
Oskar Eriksson ◽  
Barbro Persson ◽  
Miklos Lipcsey ◽  
...  
Keyword(s):  
Critically Ill ◽  
Complement Activation ◽  
Tertiary Hospital ◽  
Mannose Binding Lectin ◽  
Lectin Pathway ◽  
Strongly Correlated ◽  
Increased Risk ◽  
Mannose Binding ◽  
Patients At Risk ◽  
Binding Lectin

AbstractThe ongoing COVID-19 pandemic has caused significant morbidity and mortality worldwide, as well as profound effects on society. COVID-19 patients have an increased risk of thromboembolic (TE) complications, which develop despite pharmacological thromboprophylaxis. The mechanism behind COVID-19-associated coagulopathy remains unclear. Mannose-binding lectin (MBL), a pattern recognition molecule that initiates the lectin pathway of complement activation, has been suggested as a potential amplifier of blood coagulation during thromboinflammation. Here we describe data from a cohort of critically ill COVID-19 patients (n = 65) treated at a tertiary hospital center intensive care unit (ICU). A subset of patients had strongly elevated MBL plasma levels, and activity upon ICU admission, and patients who developed symptomatic TE (14%) had significantly higher MBL levels than patients without TE. MBL was strongly correlated to plasma D-dimer levels, a marker of COVID-19 coagulopathy, but showed no relationship to degree of inflammation or other organ dysfunction. In conclusion, we have identified complement activation through the MBL pathway as a novel amplification mechanism that contributes to pathological thrombosis in critically ill COVID-19 patients. Pharmacological targeting of the MBL pathway could be a novel treatment option for thrombosis in COVID-19. Laboratory testing of MBL levels could be of value for identifying COVID-19 patients at risk for TE events.

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