Soluble factors from multipotent mesenchymal stromal cells have antinecrotic effect on cardiomyocytes in vitro and improve cardiac function in infarcted rat hearts.
The mechanisms underlying the functional improvement after injection of multipotent mesenchymal stromal cells (MSCs) in infarcted hearts remain incompletely understood. The aim of this study was to investigate if soluble factors secreted by MSCs promote cardioprotection. For this purpose,  conditioned medium (CM) was obtained after three passages from MSC cultures submitted to 72 h of conditioning in serum-free DMEM under normoxia (NCM) or hypoxia (HCM) conditions. CM was concentrated 25-fold before use (NCM-25X, concentrated normoxia conditioned medium; HCM-25X, concentrated  hypoxia conditioned medium). The in vitro cardioprotection was evaluated in neonatal ventricular cardiomyocytes by quantifying apoptosis after 24 h of serum deprivation associated with hypoxia (1% O(2)) in the absence or presence of NCM and HCM (nonconcentrated and 25-fold concentrated).  The in vivo cardioprotection of HCM was tested in a model of myocardial infarction (MI) induced in Wistar male rats by permanent left coronary occlusion. Intramyocardial injection of HCM-25X (n = 14) or nonconditioned DMEM (n = 16) was performed 3 h after coronary occlusion and  cardiac function was evaluated 19-21 days after medium injection. Cardiac function was evaluated by electro- and echocardiogram, left ventricular catheterization, and treadmill test. The in vitro results showed that HCM was able to decrease cardiomyocyte necrosis. The in vivo results  showed that HCM-25X administered 3 h after AMI was able to promote a significant reduction (35%) in left ventricular end-diastolic pressure and improvement of cardiac contractility (15%) and relaxation (12%). These results suggest that soluble factors released in vitro by MSCs are able to  promote cardioprotection in vitro and improve cardiac function in vivo.
Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, Brazil.
P
P
Fidelis-de-Oliveira
J P S
JP
Werneck-de-Castro
V
V
Pinho-Ribeiro
B C M
BC
Shalom
J H
JH
Nascimento-Silva
R H
RH
Costa e Souza
I S
IS
Cruz
R R
RR
Rangel
R C S
RC
Goldenberg
A C
AC
Campos-de-Carvalho
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015687:Cell Hypoxia; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D016895:Culture Media, Serum-Free; D004452:Echocardiography; D006321:Heart / Q000503:physiopathology; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D016277:Ventricular Function, Left / Q000187:drug effects
D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free