الفهرس 
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Abstract
Subcutaneous human adipose tissue is an abundant source of MSCs, which are promising for several therapeutic applications in esthetic and regenerative medicine. For a long time, adipose tissue has been considered to be an inert tissue and has usually been discarded as surgical waste after liposuction. Nevertheless, it is a highly vascularized tissue and an abundant source of multiple cell types such as MSCs.
MSCs with similar characteristics can be found in a variety of other tissues including the bone marrow, muscle, connective tissue, skin, placenta, blood, cord blood, synovium, periosteum, and perichondrium. BM-MSCs have been extensively used since their discovery in the early 70s, but harvesting bone marrow is accompanied by certain drawbacks including painful procurement as well as low stem cell yield. In comparison to BM-MSCs, MSCs from adipose tissue occur at higher frequency within adipose tissue on a volume basis. Harvesting adipose tissue is minimally invasive and less painful, and liposuction is one of the most commonly performed cosmetic procedures without general anesthesia. Additionally, the adipose source offers two options for selection of regenerative cells: the SVF and the ADSCs contained therein.
The aim of the work is to study the ability of ADSCs differentiation into cardiomyocytes using 5-azacytidine.
The present study included 25 liposuction samples. All samples were subjected to the followings: Isolation of ADSCs was done using enzymatic collagenase digestion with high yield isolation. The cells then identified by their morphology (fibroblast like cells) and flowcytometri analysis of cell surface markers (CD34-, CD44+, CD73+). Moreover, differentiation into cardiomyocytes was done using 5-azacytidine and cardiac cells were identified by their morphological changes (cells showed binucleation, extended cytoplasmic processes with adjacent cells, then form cardiac bundles, At 2 weeks, the cells increased in size and formed a ball-like appearance) and cell surface markers (positive troponin and positive vimentin).
The results were tabulated and statistically analyzed. The results revealed that:
As regards ADSCs morphological changes: At day 7, cells showed multi-polar fibroblastoid cells and 60 % confluence which gradually increased to reach 80 % - 90 % confluence at about 9 days.
As regards Flowcytometric Detection of ADSCs:
Before differentiation ADSCs showed negative expression of vimentin (R=2.0 – 13.0%) with mean value 6.44 ± 3.39 and negative expression of troponin (R=1.0 – 2.90%) with mean value 1.70 ± 0.60.
ADSCs showed negative expression of CD34 (R=0.10 – 1.90%) with mean value 1.03 ± 0.55.
ADSCs showed positive expression of CD44 (R=59.0 –82.0 %) with mean value 75.2 ± 5.40.
ADSCs showed positive expression of CD73 (R= 64.0 – 87.0 %) with mean value 75.88 ± 7.18.
As regards Post-induction morphological changes: ADSCs when treated with 5-azacytidine showed the followings; At 1 week, some cells showed binucleation, extended cytoplasmic processes with adjacent cells and formed cardiac bundles. At 2 weeks, the cells increased in size and formed a ball-like appearance.
As regards Flowcytometric Detection of cardiomyocytes: Flowcytometric analysis of vimentin and troponin on the cells was done before and after differentiation with a cut off 20% (> 20% is considered positive) and showed the following results:
Vimentin (R=2.0 – 13.0%) with mean value 6.44 ± 3.39 and when these cells were treated with 5-azacytidine, they showed expression of positive vimentin (R=40.0 – 75.0%) with mean value 62.44 ± 9.8.
Troponin (R=1.0 – 2.90%) with mean value 1.70 ± 0.60, then when these cells were treated with 5-azacytidine, they showed expression of positive troponin (R=62.0 – 91.0%) with mean value 77.24 ± 8.36. Comparing between before and after differentiation of ADSCs showed highly significant difference (P<0.001).