Mature, adipocyte derived, dedifferentiated fat cells can differentiate into smooth muscle-like cells and contribute to bladder tissue regeneration.
OBJECTIVE
We recently reported that mature, adipocyte derived, dedifferentiated fat cells show high proliferative activity and multilineage differentiation potential. In the current study we investigated whether such cells could differentiate into a smooth muscle cell lineage and contribute to bladder tissue regeneration in a mouse bladder injury model.


METHODS
Human adipocyte derived dedifferentiated fat cells were cultured for 1 week under conditions favorable for smooth muscle cell differentiation and immunostained for alpha-smooth muscle actin. The expression of smooth muscle cell marker genes for differentiating dedifferentiated fat cells was measured by real-time reverse transcription-polymerase chain reaction. Green fluorescence protein labeled dedifferentiated fat cells were injected into cryo-injured bladder walls in mice. The ability of the fat cells to regenerate smooth muscle tissue was examined immunohistochemically 14 and 30 days after transplantation.


RESULTS
Immunohistochemical analysis revealed that more than 50% of the fat cells were successfully differentiated into alpha-smooth muscle actin positive cells under the optimum culture condition of a medium containing 5% fetal bovine serum and 5 ng/ml transforming growth factor-beta1. Real-time reverse transcription-polymerase chain reaction revealed increased expression of SM22alpha, alpha-smooth muscle actin and smooth muscle-myosin heavy chain in dedifferentiated fat cells during week 1 of differentiation culture. Cells expressing alpha-smooth muscle actin plus green fluorescence protein were observed at the bladder wall injection sites in mice 14 and 30 days after transplantation. Alpha-smooth muscle actin positive areas in injured bladder tissue in mice with fat cell injection were significantly larger than those in saline injected control mice.


CONCLUSIONS
These findings suggest that dedifferentiated fat cells can differentiate into smooth muscle cell lineages and contribute to the regeneration of bladder smooth muscle tissue.
Sakuma
Takahiro
T
Department of Urology, Nihon University School of Medicine, Nihon University, Tokyo, Japan.
Matsumoto
Taro
T
Kano
Koichiro
K
Fukuda
Noboru
N
Obinata
Daisuke
D
Yamaguchi
Kenya
K
Yoshida
Toshio
T
Takahashi
Satoru
S
Mugishima
Hideo
H
D017667:Adipocytes / Q000166:cytology* / Q000502:physiology; D000818:Animals; D054337:Cell Dedifferentiation / Q000502:physiology*; D002454:Cell Differentiation; D017690:Cell Transplantation / Q000379:methods; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000502:physiology; D011336:Probability; D011897:Random Allocation; D012038:Regeneration / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D001743:Urinary Bladder / Q000166:cytology* / Q000293:injuries; D001745:Urinary Bladder Diseases / Q000473:pathology / Q000601:surgery