Activated human polymorphonuclear leucocytes reduce rabbit papillary muscle function: role of the CD18 glycoprotein adhesion complex.
OBJECTIVE
The aim was to determine if human polymorphonuclear leucocytes activated by human recombinant C5a (hrC5a) reduce the contractile function of the isolated papillary muscle and if this response depends upon the functional integrity of the CD18 glycoprotein adhesion complex.


METHODS
Human neutrophils with or without pretreatment with monoclonal antibodies to the CD18 adhesion complex were added to organ baths containing isolated papillary muscles of the rabbit and activated with hrC5a. Changes in papillary muscle function were measured.


METHODS
52 right ventricular papillary muscles isolated from rabbit and neutrophils isolated from human whole blood were used.


RESULTS
Neither neutrophils nor hrC5a alone reduced papillary muscle function, but activation of neutrophils with hrC5a provoked reduction in myocardial contractility. This correlated with the degree of neutrophil stimulation, assessed by cell aggregation. Pretreatment of neutrophils with antibodies to the CD18 adhesion complex significantly attenuated the neutrophil induced contractile impairment.


CONCLUSIONS
Activated human neutrophils can impair contractile function of papillary muscles, which is dependent upon adhesion of the leucocytes to the muscle via the CD18 complex.
Department of Pharmacology, New York Medical College, Valhalla.
R
R
Kraemer
C W
CW
Smith
K M
KM
Mullane
D000818:Animals; D015703:Antigens, CD / Q000502:physiology*; D018821:CD18 Antigens; D002449:Cell Aggregation; D002478:Cells, Cultured; D015936:Complement C5a / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008297:Male; D009200:Myocardial Contraction; D009504:Neutrophils / Q000502:physiology*; D010210:Papillary Muscles / Q000502:physiology*; D011817:Rabbits; D016028:Receptors, Leukocyte-Adhesion / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology
D015703:Antigens, CD; D018821:CD18 Antigens; D016028:Receptors, Leukocyte-Adhesion; D011994:Recombinant Proteins; D015936:Complement C5a; D006861:Hydrogen Peroxide