A preliminary approach to the repair of myocardial infarction using adipose tissue-derived stem cells encapsulated in magnetic resonance-labelled alginate microspheres in a porcine model.

Adipose tissue-derived stem cells (ASCs) have properties of self-renewal, pluripotency and high proliferative capability that make them useful for the treatment of cardiac ventricular function following ischaemic injury. However, their therapeutic use is limited due to the low retention of the cells at the targeted site. To address this issue, we developed semipermeable membrane microcapsules labelled with Endorem (magnetocapsules) that provide mechanical and immunological immune protection to the cells while maintaining internal cell microenvironment. In addition, the particles allow tracking the presence and migration of injected cells in vivo by Magnetic Resonance Imaging (MRI). Results indicate that after 21 days in culture, the cells encapsulated in the magnetocapsules showed similar viabilities than cells encapsulated in conventional microcapsules. MRI confirmed a gradual loss of the intensity of the iron oxide label in the non-encapsulated Endorem labelled cells, while magnetocapsules were detected throughout the study period, suggesting that cell retention in the myocardium is improved when cells are enclosed within the magnetocapsules. To further evaluate treatment's effect on global cardiac function, MRI determination of infarct size and left ventricular ejection fraction (LVEF) was performed. In vivo results showed no statistically significant differences in heart rate and cardiac output between treatment groups. In conclusion, cells enclosed within magnetocapsules have shown suitable viability and have been detected in vivo throughout the study period. Further studies will evaluate whether increasing cell loading with the particles may help to improve the therapeutic results.