Povilas Barasa has defended his thesis entitled "Adipose Stem Cell Secretome and Bioprinted Tissues: Potential Treatments of Urethral Fibrosis" for the degree of Doctor of Biochemistry.
Scientific consultants: Prof. Dr. Daiva Baltriukienė (Vilnius University, Natural Sciences, Biochemistry); Prof. Dr. Elena Kozlova (Uppsala University, Natural Sciences, Biochemistry).
Composition of the Dissertation Defense Board: Chairperson - Assoc. Prof. Dr. Aušra Sasnauskienė (Vilnius University, Natural Sciences, Biochemistry); Prof. Dr. Gediminas Čepinskas (Centre for Critical Illness Research, Canada, Natural Sciences, Biochemistry); Prof. Dr. Rūta Navakauskienė (Vilnius University, Natural Sciences, Biochemistry); Dr. Augustas Pivoriūnas (Inovative Medicine Centre, Natural Sciences, Biochemistry); Dr. Giulio Preta (Vilnius University, Natural Sciences, Biochemistry).
Urethral strictures – a pathological narrowing of the urethra caused by scarring (fibrosis) – affect between 200 and 1,200 out of every 100,000 people. Two significant shortcomings of current treatment methods are the need for donor tissue for transplantation (in the case of urethroplasty) and a substantial likelihood of disease recurrence after therapy. More effective treatment options could involve using molecules secreted by stem cells – the secretome – or artificial urethral tissue embedded with differentiated stem cells.
This study aimed to evaluate the effectiveness of autologous stem cells in reducing fibrosis marker levels in human fibroblasts in vitro and in restoring urethral structure in vivo using a rabbit model.
The first part of the study analyzed the effect of a medium enriched with the secretome of human adipose-derived stem cells on urethral fibroblasts. It was shown that this medium does not inhibit the fibrosis process in vitro.
The second part describes the development process of bio-printed artificial urethral tissue composed of a hydrogel with embedded cells. This tissue's mechanical properties and the encapsulated cells' viability were investigated.
Further, methods were described for differentiating stem cells derived from rabbit oral mucosa and adipose tissue into epithelial and smooth muscle cells, respectively. Histological analysis confirmed that the artificial tissue containing these cells can integrate into the rabbit urethra.
Finally, the tissue fabrication methodology was tested with human cells to produce constructs of similar structure.
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