BME Joint Graduate Program Seminar

Martina Doubková, MSc. and Simon Prazak, MSc.
Institute of Physiology of the Czech Academy of Sciences

Attendance is MANDATORY for all BME graduate and honors students.

Friday, October 11, 2024

3:30 - 4:30 PM
University of Tennessee Health Science Center

North Auditorium, Coleman Building

956 Court Ave.

Abstracts

ABSTRACT 1: Amelioration of fibrosis in the contracted tissue of clubfoot: An in vitro model to identify potential therapeutic agents

Doubková M. 1,2, Knitlova J. 1, Eckhardt A. 3, Vondrasek D. 4, Filova E. 1, Ostadal M. 5, Novotny T. 6

1. Laboratory of Biomaterials and Tissue Engineering, Institute of Physiology, The Czech Academy of Sciences, Prague
2. Czech Republic
3. Second Faculty of Medicine, Charles University, Prague, Czech Republic
4. Laboratory of Translational Metabolism, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
5. Laboratory of Biomathematics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
6. Department of Orthopaedics, Na Bulovce Hospital, Prague, Czech Republic
7. Department of Orthopaedics, Masaryk Hospital, Usti nad Labem, Czech Republic

Idiopathic clubfoot is the second most common congenital orthopedic deformity of the lower limb. The stiff,contracted tissue mass formed between the medial malleolus, sustentaculum tali, and os naviculare, causes thefoot to rotate inward and downward. The contracted tissue of clubfoot exhibits increased amounts of type I, III, V,and VI collagen, fibronectin, tenascin-C, TGF-β, smooth muscle α-actin, increased collagen cross-linking andcross-linking enzymes. Increased deposition of extracellular matrix (ECM) proteins, especially fibrillar collagens,and growth factors that regulate cell behavior to drive the ECM deposition are typical in fibroproliferativeconnective tissue diseases such as Dupuytren’s contracture and hypertrophic scars. Fibrotic changes in pediatricclubfoot provide an opportunity to improve corrective therapy and prevent relapses with targeted drugs. Usingclubfoot-derived primary fibroblast cell cultures, we have established in vitro models to identify potentialtherapeutic agents. We evaluated the effect of selected antifibrotic substances (minoxidil, β-aminopropionitrile,relaxin, ilomastat) in standard cell culture, in 3D collagen-based hydrogels and a simple pseudo-3D biomimeticenvironment induced by the water-soluble polymers Ficoll and Polyvinylpyrrolidone, using the principle ofmacromolecular crowding. Our model environment stimulated a higher conversion of soluble collagen intoinsoluble collagen, accelerated the formation of the ECM layer, collagen cross-linking, and up-regulation offibrosis-related genes in clubfoot fibroblasts, similarly to the original tissue. In subsequent experiments, minoxidileffectively blocked the expression of lysyl hydroxylases, limiting the formation of collagen cross-links in both themodel and control environment. Our findings provide a tool for expanding preclinical research for clubfoot andsimilar fibroproliferative conditions.

ABSTRACT 2: Utilization of Hydrogels Seeded with Mesenchymal Stromal Cells for Tissue Engineering

Simon Prazak, MSc.

The use of allogeneic mesenchymal stromal cells (MSCs) for treating vascular and osteochondral defects is currently generating significant interest both research and clinical settings. Umbilical cord tissue-derived MSCs (WJSCs) have emerged as a frequently utilized source of allogeneic stem cells due to their abundant supply, high growth capacity, and non-invasive isolation method. Current cardiovascular patches made off synthetic materials are non-degradable and stiff. Mismatch in mechanical properties causes intimal hyperplasia and calcification. We prepared vascular patches based on reinforced composite hydrogels cellularized with WJSCs and differentiated into a smooth muscle phenotype that mimics the tunica media of native vessels. The reinforcement of these gels has more functions, e.g. improves mechanical properties of the gel and supports mesenchymal stem cell growth and differentiation.  In addition, we have provided a comprehensive evaluation of the safety, efficacy, and regenerative potential of WJSCs for the treatment of osteochondral defects. Our novel approach combines cell-based and cell-free advanced therapies by utilizing spheroids and spheroid-conditioned media derived from WJSCs for repairing damaged cartilage in a pig model. To facilitate the treatment, MSC spheroids were immobilized within the clinically-approved hyaluronan scaffold using a fibrin-based hydrogel. The resulting 3D grafts were then implanted into artificial osteochondral defect of pigs.