METHODS: Human adipose-derived stem cells isolated from fat tissues were differentiated into smooth muscle cells and then seeded onto a triple-layered PLGA sheet to form a bladder construct. Adult athymic rats underwent subtotal urinary bladder resection and were divided into three treatment groups (n = 3): Group 1 ("sham") underwent anastomosis of the remaining basal region, Group 2 underwent reconstruction with the cell-free scaffold, and Group 3 underwent reconstruction with the tissue-engineered bladder construct. Animals were monitored on a daily basis and euthanisation was performed 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 weeks post-operation. It was found that by Day 14, substantial ingrowth of smooth muscle and urothelial cells had occurred in Group 2 and 3. In the long-term follow up of group 3 (tissue-engineered bladder construct group), it was found that the urinary bladder wall was completely regenerated and bladder function was fully restored. Urodynamic and radiological evaluations of the reconstructed bladder showed a return to normal bladder volume and function.Histological analysis revealed the presence of three muscular layers and a urothelium similar to that of a normal bladder. Immunohistochemical staining using human-specific myocyte markers (myosin heavy chain and smoothelin) confirmed the incorporation of the seeded cells in the newly regenerated muscular layers.
CONCLUSION: Implantation of PLGA construct seeded with smooth muscle cells derived from human adipose stem cells can lead to regeneration of the muscular layers and urothelial ingrowth, leading to formation of a completely functional urinary bladder.
Results: This review discusses the current status of mesenchymal stem cell (MSC) therapy for SCI, criteria to considering for the application of MSC therapy and novel biological therapies that can be applied together with MSCs to enhance its efficacy. Bone marrow-derived MSCs (BMSCs), umbilical cord-derived MSCs (UC-MSCs) and adipose tissue-derived MSCs (ADSCs) have been trialed for the treatment of SCI. Application of MSCs may minimize secondary injury to the spinal cord and protect the neural elements that survived the initial mechanical insult by suppressing the inflammation. Additionally, MSCs have been shown to differentiate into neuron-like cells and stimulate neural stem cell proliferation to rebuild the damaged nerve tissue.
Conclusion: These characteristics are crucial for the restoration of spinal cord function upon SCI as damaged cord has limited regenerative capacity and it is also something that cannot be achieved by pharmacological and physiotherapy interventions. New biological therapies including stem cell secretome therapy, immunotherapy and scaffolds can be combined with MSC therapy to enhance its therapeutic effects.
METHODS: In this review, we first discussed the anatomy, physiology and pathophysiology of tendon and ligament injuries and its current treatment. Secondly, we explored the current role of tendon and ligament tissue engineering, describing its recent advances. After that, we also described stem cell and cell secreted product approaches in tendon and ligament injuries. Lastly, we examined the role of the bioreactor and mechanical loading in in vitro maturation of engineered tendon and ligament.
RESULTS: Tissue engineering offers various alternative ways of treatment from biological tissue constructs to stem cell therapy and cell secreted products. Bioreactor with mechanical stimulation is instrumental in preparing mature engineered tendon and ligament substitutes in vitro.
CONCLUSIONS: Tissue engineering showed great promise in replacing the damaged tendon and ligament. However, more study is needed to develop ideal engineered tendon and ligament.
METHODs: Data collection was based on the key articles published in English language in years between 2006 and 2018 using the searching terms of urethral stricture and tissue engineering on PubMed database.
RESULTS: Differentiation of mesenchymal stem cells into urothelial and smooth muscle cells to be used for urologic application does not offer any advantage over autologous urothelial and smooth muscle cells. Among studied scaffolds, synthetic scaffolds with proper porosity and mechanical strength is the best option to be used for urethral tissue engineering.
CONCLUSION: Hypoxia-preconditioned mesenchymal stem cells in combination with autologous cells seeded on a pre-vascularized synthetic and biodegradable scaffold can be said to be the best combinatory strategy in engineering of human urethra.