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An essential role for complement C5a in the pathogenesis of septic cardiac dysfunction
Andreas D Niederbichler1, Laszlo M Hoesel, Margaret V Westfall
1Department of Surgery, The University of Michigan Medical School, Ann Arbor, MI 48109, USA.
The Journal of Experimental Medicine
|December 29, 2005
Summary
Sepsis impairs heart function by activating the complement system. Blocking C5a, a complement component, prevented sepsis-induced cardiac dysfunction in rats, highlighting a key mechanism.
Area of Science:
- Cardiovascular Biology
- Immunology
- Sepsis Pathophysiology
Background:
- Sepsis-induced cardiomyopathy is a critical complication.
- The complement system is extensively activated during sepsis.
- C5a and its receptor (C5aR) are implicated in inflammatory responses.
Purpose of the Study:
- To investigate the role of complement component C5a in sepsis-induced cardiac dysfunction.
- To examine the expression and function of the C5a receptor (C5aR) on cardiomyocytes during sepsis.
Main Methods:
- Cecal ligation and puncture (CLP) model in rats to induce sepsis.
- In vivo assessment of cardiac function (left ventricular pressures).
- In vitro evaluation of cardiomyocyte contractility and C5aR expression.
Main Results:
- CLP rats exhibited significantly reduced cardiac function and cardiomyocyte contractility.
- Administration of a C5a-blocking antibody prevented these cardiac defects.
- C5a receptor (C5aR) expression increased on cardiomyocytes post-CLP.
- Exogenous C5a induced greater contractile dysfunction in cardiomyocytes from CLP rats.
Conclusions:
- Sepsis induces C5a receptor (C5aR) expression on cardiomyocytes.
- In vivo generated C5a interacts with C5aR, leading to cardiomyocyte dysfunction.
- This C5a-C5aR interaction contributes to sepsis-induced cardiomyopathy.