Cell therapy attenuates cardiac dysfunction post myocardial infarction: effect of timing, routes of injection and a fibrin scaffold.
BACKGROUND
Cell therapy approaches for biologic cardiac repair hold great promises, although basic fundamental issues remain poorly understood. In the present study we examined the effects of timing and routes of administration of bone marrow cells (BMC) post-myocardial infarction (MI) and the efficacy of an injectable biopolymer scaffold to improve cardiac cell retention and function.


RESULTS
(99m)Tc-labeled BMC (6 x 10(6) cells) were injected by 4 different routes in adult rats: intravenous (IV), left ventricular cavity (LV), left ventricular cavity with temporal aorta occlusion (LV(+)) to mimic coronary injection, and intramyocardial (IM). The injections were performed 1, 2, 3, or 7 days post-MI and cell retention was estimated by gamma-emission counting of the organs excised 24 hs after cell injection. IM injection improved cell retention and attenuated cardiac dysfunction, whereas IV, LV or LV* routes were somewhat inefficient (<1%). Cardiac BMC retention was not influenced by timing except for the IM injection that showed greater cell retention at 7 (16%) vs. 1, 2 or 3 (average of 7%) days post-MI. Cardiac cell retention was further improved by an injectable fibrin scaffold at day 3 post-MI (17 vs. 7%), even though morphometric and function parameters evaluated 4 weeks later displayed similar improvements.


CONCLUSIONS
These results show that cells injected post-MI display comparable tissue distribution profile regardless of the route of injection and that there is no time effect for cardiac cell accumulation for injections performed 1 to 3 days post-MI. As expected the IM injection is the most efficient for cardiac cell retention, it can be further improved by co-injection with a fibrin scaffold and it significantly attenuates cardiac dysfunction evaluated 4 weeks post myocardial infarction. These pharmacokinetic data obtained under similar experimental conditions are essential for further development of these novel approaches.
Nakamuta
Juliana S
JS
Heart Institute (InCor), University of São Paulo Medical School, São Paulo, São Paulo, Brazil.
Danoviz
Maria E
ME
Marques
Fabio L N
FL
dos Santos
Leonardo
L
Becker
Claudia
C
Gonçalves
Giovana A
GA
Vassallo
Paula F
PF
Schettert
Isolmar T
IT
Tucci
Paulo J F
PJ
Krieger
Jose E
JE
D000818:Animals; D001704:Biopolymers / Q000737:chemistry; D001854:Bone Marrow Cells / Q000166:cytology; D016026:Bone Marrow Transplantation / Q000379:methods; D064987:Cell- and Tissue-Based Therapy / Q000379:methods*; D005337:Fibrin / Q000737:chemistry*; D006331:Heart Diseases / Q000503:physiopathology / Q000628:therapy; D006439:Hemodynamics; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D051381:Rats; D011917:Rats, Inbred Lew; D013667:Technetium / Q000737:chemistry; D013997:Time Factors
D001704:Biopolymers; D013667:Technetium; D005337:Fibrin