European Journal of Cardio-Thoracic Surgery, Vol 11, 818-823, Copyright © 1997 by European Association for Cardio-thoracic Surgery
Increased growth factor transcription after pulmonary artery banding
EP Bauer, S Kuki, M Arras, R Zimmerman and W Schaper
Division of Cardiothoracic Surgery, Max-Planck-Institute for Clinical and Physiological Research, Kerckhoff-Clinic, Bad Nauheim, Germany. Erwin.P.Bauer@kerckhoff.med.uni-giessen.de
OBJECTIVE: Several mechanisms are known to produce mechanical stress during
and after cardiac surgery, e.g. aortic cross-clamping and pulmonary artery
banding (PAB). However, little is known about the transcription of
myocardial genes which are changed during mechanical overload. This study
was performed to investigate growth factor mRNA expression after PAB in
porcine hearts. METHODS: The experiment was performed in 35 pigs (five
groups). Each group consisted of three sham- pigs (S-pigs) and four
banding-pigs (B-pigs). The mean transbanding gradient in B-pigs was 29 +/-
2.5 mm Hg. The hearts were excised after different time intervals. The
probes were snap-frozen in liquid nitrogen and stored at -80 degrees C.
Analysis was performed by Northern blot. RESULTS: Right ventricular weight
increased significantly after 7 and 24 days (P < 0.05). There was an
upregulation of transcriptional and growth factors in B-pigs: c-jun mRNA:
412 +/- 12.1% after 2 h (P < 0.001); c-fos mRNA: 303 +/- 18.5% after 2 h
(P < 0.001); vascular endothelial growth factor (VEGF) mRNA: 203 +/-
18.2% after 2 h (P < 0.001); Flk-1 mRNA: 156 +/- 16% after 2 h (P <
0.05), 253 +/- 5% after 24 h (P < 0.01) and 184 +/- 12% after 3 days (P
< 0.01); transforming growth factor-beta1 (TGF-beta1) mRNA: 255 +/-
21.5% after 24 h (P < 0.002). Fibroblast growth factors 1 and 2 (FGF-1
and FGF-2) were constitutively expressed in B- and S-pigs and did not
change their expression. CONCLUSIONS: Pulmonary artery banding results in
significant right ventricular hypertrophy and upregulation of different
growth factors. However, growth factors known to induce hypertrophy in
vitro, like the FGFs, showed unchanged expression. We think that myocardial
growth factors may have trophic functions in the heart which may be useful
for cardiac surgery in future.
