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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
PubMed

Insights

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.

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