Serum components stimulate pericardial tissue contraction.
OBJECTIVE
Previous experiments have demonstrated the retraction and fibrosis of vital autologous pericardial flap implants in the descending aorta of sheep. An in-vitro model of pericardial tissue contraction was developed that showed healing reactions similar to those observed in the fresh in-vivo flap. Here, the component(s) of serum that stimulate tissue contraction were partially characterized. The molecular weight range and stability (heat and protease resistance) of the serum component(s) are described. Tissue contraction also requires de-novo protein synthesis.


METHODS
Sections (1 cm2) of sheep pericardium were incubated with fractionated, heat-treated, or protease-treated fetal bovine serum for 14 days. In addition, SDS-PAGE protein profiles were generated using tissues incubated with and without cycloheximide for up to 12 days.


RESULTS
Tissue contraction was observed in molecular weight serum fractions > or =5 kDa, as well as in samples incubated with heat and protease-treated serum. SDS-PAGE showed the appearance of a protein band after day 4 during the process of tissue contraction that was absent in samples incubated with cycloheximide.


CONCLUSIONS
Serum fractions > or =5 kDa stimulated protein synthesis and pericardial tissue contraction. The active component(s) was shown to be heat stable, but partially sensitive to protease. The addition of cycloheximide to the culture medium, shown previously to prevent pericardial tissue contraction, inhibited de-novo synthesis of the protein that appeared during the process of tissue contraction.
Marchion
Douglas C
DC
The International Heart Institute of Montana, Missoula 59802, USA.
Sticka
Josh J
JJ
Han
Tian Hao
TH
Weber
Patricia A
PA
Cheung
David T
DT
Grobe
Albert C
AC
Duran
Carlos M G
CM
D000818:Animals; D001798:Blood Proteins / Q000096:biosynthesis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003470:Culture Media / Q000494:pharmacology; D046508:Culture Techniques; D003513:Cycloheximide / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D023421:Models, Animal; D008955:Models, Cardiovascular; D008970:Molecular Weight; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D010496:Pericardium / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D010949:Plasma / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012016:Reference Values; D012756:Sheep
D001798:Blood Proteins; D003470:Culture Media; D011500:Protein Synthesis Inhibitors; D003513:Cycloheximide