Stimulation of coronary collateral growth by granulocyte stimulating factor: role of reactive oxygen species.
OBJECTIVE
The purpose of this study was to determine whether G-CSF promotes coronary collateral growth (CCG) and decipher the mechanism for this stimulation.


RESULTS
In a rat model of repetitive episodic myocardial ischemia (RI, 40 seconds LAD occlusion every 20 minutes for 2 hours and 20 minutes, 3 times/d for 5 days) CCG was deduced from collateral-dependent flow (flow to LAD region during occlusion). After RI, G-CSF (100 microg/kg/d) increased CCG (P<0.01) (0.47+/-0.15) versus vehicle (0.14+/-0.06). Surprisingly, G-CSF treatment without RI increased CCG (0.57+/-0.18) equal to G-CSF+RI. We evaluated ROS by dihydroethidine (DHE) fluorescence (LV injection, 60 microg/kg, during two episodes of ischemia). DHE fluorescence was double in G-CSF+RI versus vehicle+RI (P<0.01), and even higher in G-CSF without RI (P<0.01). Interestingly, the DHE signal did not colocalize with myeloperoxidase (immunostaining, neutrophil marker) but appeared in cardiac myocytes. The study of isolated cardiac myocytes revealed the cytokine stimulates ROS which elicit production of angiogenic factors. Apocynin inhibited G-CSF effects both in vivo and in vitro.


CONCLUSIONS
G-CSF stimulates ROS production directly in cardiomyocytes, which plays a pivotal role in triggering adaptations of the heart to ischemia including growth of the coronary collaterals.
Carrão
Ana Catarina R
AC
Centre for Cardiovascular Research, Charité Medical University, Berlin, Germany.
Chilian
William M
WM
Yun
June
J
Kolz
Christopher
C
Rocic
Petra
P
Lehmann
Kerstin
K
van den Wijngaard
Jeroen P H M
JP
van Horssen
Pepijn
P
Spaan
Jos A E
JA
Ohanyan
Vahagn
V
Pung
Yuh Fen
YF
Buschmann
Ivo
I
D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D003097:Collateral Circulation / Q000187:drug effects / Q000502:physiology*; D003326:Coronary Circulation / Q000187:drug effects; D004195:Disease Models, Animal; D004452:Echocardiography; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism* / Q000494:pharmacology; D006334:Heart Function Tests; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D011336:Probability; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012016:Reference Values
D017382:Reactive Oxygen Species; D016179:Granulocyte Colony-Stimulating Factor