ABSTRACT
BACKGROUND@#The urinary tract can be affected by both congenital abnormalities as well as acquired disorders, such ascancer, trauma, infection, inflammation, and iatrogenic injuries, all of which may lead to organ damage requiring eventualreconstruction. As a gold standard, gastrointestinal segment is used for urinary bladder reconstruction. However, one majorproblem is that while bladder tissue prevents reabsorption of specific solutes, gastrointestinal tissue actually absorbs them.Therefore, tissue engineering approach had been attempted to provide an alternative tissue graft for urinary bladderreconstruction. @*METHODS@#Human adipose-derived stem cells isolated from fat tissues were differentiated into smooth muscle cells andthen seeded onto a triple-layered PLGA sheet to form a bladder construct. Adult athymic rats underwent subtotal urinarybladder resection and were divided into three treatment groups (n = 3): Group 1 (‘‘sham’’) underwent anastomosis of theremaining basal region, Group 2 underwent reconstruction with the cell-free scaffold, and Group 3 underwent reconstructionwith the tissue-engineered bladder construct. Animals were monitored on a daily basis and euthanisation wasperformed whenever a decline in animal health was detected. @*RESULTS@#All animals in Groups 1, 2 and 3 survived for at least 7 days and were followed up to a maximum of 12 weekspost-operation. It was found that by Day 14, substantial ingrowth of smooth muscle and urothelial cells had occurred inGroup 2 and 3. In the long-term follow up of group 3 (tissue-engineered bladder construct group), it was found that theurinary bladder wall was completely regenerated and bladder function was fully restored. Urodynamic and radiologicalevaluations of the reconstructed bladder showed a return to normal bladder volume and function.Histological analysisrevealed the presence of three muscular layers and a urothelium similar to that of a normal bladder. Immunohistochemicalstaining using human-specific myocyte markers (myosin heavy chain and smoothelin) confirmed the incorporation of theseeded cells in the newly regenerated muscular layers. @*CONCLUSION@#Implantation of PLGA construct seeded with smooth muscle cells derived from human adipose stemcells can lead to regeneration of the muscular layers and urothelial ingrowth, leading to formation of a completelyfunctional urinary bladder.
ABSTRACT
BACKGROUND@#The urinary tract can be affected by both congenital abnormalities as well as acquired disorders, such ascancer, trauma, infection, inflammation, and iatrogenic injuries, all of which may lead to organ damage requiring eventualreconstruction. As a gold standard, gastrointestinal segment is used for urinary bladder reconstruction. However, one majorproblem is that while bladder tissue prevents reabsorption of specific solutes, gastrointestinal tissue actually absorbs them.Therefore, tissue engineering approach had been attempted to provide an alternative tissue graft for urinary bladderreconstruction. @*METHODS@#Human adipose-derived stem cells isolated from fat tissues were differentiated into smooth muscle cells andthen seeded onto a triple-layered PLGA sheet to form a bladder construct. Adult athymic rats underwent subtotal urinarybladder resection and were divided into three treatment groups (n = 3): Group 1 (‘‘sham’’) underwent anastomosis of theremaining basal region, Group 2 underwent reconstruction with the cell-free scaffold, and Group 3 underwent reconstructionwith the tissue-engineered bladder construct. Animals were monitored on a daily basis and euthanisation wasperformed whenever a decline in animal health was detected. @*RESULTS@#All animals in Groups 1, 2 and 3 survived for at least 7 days and were followed up to a maximum of 12 weekspost-operation. It was found that by Day 14, substantial ingrowth of smooth muscle and urothelial cells had occurred inGroup 2 and 3. In the long-term follow up of group 3 (tissue-engineered bladder construct group), it was found that theurinary bladder wall was completely regenerated and bladder function was fully restored. Urodynamic and radiologicalevaluations of the reconstructed bladder showed a return to normal bladder volume and function.Histological analysisrevealed the presence of three muscular layers and a urothelium similar to that of a normal bladder. Immunohistochemicalstaining using human-specific myocyte markers (myosin heavy chain and smoothelin) confirmed the incorporation of theseeded cells in the newly regenerated muscular layers. @*CONCLUSION@#Implantation of PLGA construct seeded with smooth muscle cells derived from human adipose stemcells can lead to regeneration of the muscular layers and urothelial ingrowth, leading to formation of a completelyfunctional urinary bladder.
ABSTRACT
Background: Adipose tissue provides an abundant source of multipotent cells, which represent a source of cell-based regeneration strategies for urinary bladder smooth muscle repair. Our objective was to confirm that adipose-derived stem cells (ADSCs) can be differentiated into smooth muscle cells. Methods: In this study, adipose tissue samples were digested with 0.075% collagenase, and the resulting ADSCs were cultured and expanded in vitro. ADSCs at passage two were differentiated by incubation in smooth muscle inductive media (SMIM) consisting of MCDB I31 medium, 1% FBS, and 100 U/mL heparin for three and six weeks. ADSCs in non-inductive media were used as controls. Characterisation was performed by cell morphology and gene and protein expression. Result: The differentiated cells became elongated and spindle shaped, and towards the end of six weeks, sporadic cell aggregation appeared that is typical of smooth muscle cell culture. Smooth muscle markers (i.e. alpha smooth muscle actin (ASMA), calponin, and myosin heavy chain (MHC)) were used to study gene expression. Expression of these genes was detected by PCR after three and six weeks of differentiation. At the protein expression level, ASMA, MHC, and smoothelin were expressed after six weeks of differentiation. However, only ASMA and smoothelin were expressed after three weeks of differentiation. Conclusion: Adipose tissue provides a possible source of smooth muscle precursor cells that possess the potential capability of smooth muscle differentiation. This represents a promising alternative for urinary bladder smooth muscle repair.