Gouya Ram-Liebig

Induction of proliferation and differentiation of cultured urothelial cells on acellular biomaterials

To determine the optimum conditions for the proliferation of urothelial cells, leading to the confluent coverage of large surfaces of biocompatible membranes, and for their terminal differentiation.

Regulatory challenges for autologous tissue engineered products on their way from bench to bedside in Europe.

Since the late eighties of last century the high potential of tissue engineered products (TEP)s has been shown for the treatment of various diseases and many scientific publications appeared in this field. However, only few products reached the market since. Development of TEPs is a promising but owing to its novelty a very challenging task that requires experts in this still developing field as well as ample financial resources. This paper summarises relevant regulatory challenges during quality, preclinical and clinical development of autologous TEPs in Europe. Selected strategies on how to manage major issues are presented, together with some examples from the development of an autologous TEP for urethroplasty. Considering these aspects may help other investigators with potential strategies during the development of novel TEPs.

New approaches in the modulation of bladder smooth muscle cells on viable detrusor constructs

Identification of biochemical and mechanical stimuli in order to modulate the function of bladder smooth muscle cells (SMC) in viable detrusor constructs. Human bladder detrusor cells were seeded on bladder acellular matrix and cultured under different conditions. Cell viability and proliferation were assessed by fluorescent microscopic analyses. Histological, immunohistochemical and flow cytometric analyses were performed to compare growth characteristics and differentiation of SMC. The combination of medium conditioned with proliferative urothelium and mechanical stretch resulted in a more densely populated membrane. In this culture system, the expression of α-smooth muscle actin (α-SMA) and desmin were clearly induced after serum elimination. SMC-phenotype can be modulated in viable detrusor constructs by applying selected combinations of urothelial-conditioned media and mechanical stimulation under stepwise reduction and elimination of serum.

Results of Use of Tissue-Engineered Autologous Oral Mucosa Graft for Urethral Reconstruction: A Multicenter, Prospective, Observational Trial

Background Harvest of oral mucosa for urethroplasty due to urethral stricture is associated with donor-site-morbidity. We assessed functionality and safety of an authorized tissue-engineered oral mucosa graft (TEOMG) under routine practice in stricture recurrences of any etiology, location, length and severity (real-world data). Methods 99 patients from eight centers with heterogenous urethroplasty experience levels were included in this prospective, non-interventional observational study. Primary and secondary outcomes were success rate (SR) and safety at 12 and 24 months. Findings All but one patient had ≥ 1, 77.1% (64 of 83) ≥ 2 and 31.3% (26 of 83) ≥ 4 previous surgical treatments. Pre- and postoperative mean ± SD peak flow rate (Qmax) were 8.3 ± 4.7 mL/s (n = 57) and 25.4 ± 14.7 mL/s (n = 51). SR was 67.3% (95% CI 57.6–77.0) at 12 and 58.2% (95% CI 47.7–68.7) at 24 months (conservative Kaplan Meier assessment). SR ranged between 85.7% and 0% in case of high and low surgical experience. Simple proportions of 12-month and 24-month SR for evaluable patients in all centers were 70.8% (46 of 65) and 76.9% (30 of 39). Except for one patient, no oral adverse event was reported. Interpretations TEOMG is safe and efficient in urethroplasty.

Tissue Engineering der Harnblase

ZusammenfassungIm Tissue Engineering der Harnblase mit autologer Zelltransplantation ist die hochgradige Differenzierung der in vitro auf biokompatiblen Matrizes kultivierten Zellen für die Funktionalität der Gewebekonstrukte nach der Implantation essenziell. In diesem Zusammenhang hat die terminale Differenzierung der oberflächlichen Urothelzellen (UZ) aufgrund deren Barrierefunktion gegen Urin eine entscheidende Rolle. In dieser Arbeit beschäftigen wir uns mit der Bestimmung von optimierten Konditionen für die Bildung von terminal differenziertem Urothel für die Beschichtung von größeren Flächen biologischer Membranen. Das kann uns dem Ziel der klinischen Anwendung von funktionierenden Gewebekonstrukten näher bringen.AbstractIn tissue engineering of the urinary bladder with autologous cell transplantation, high differentiation of the cells cultivated in vitro on biocompatible membranes is essential for the functionality of the tissue constructs after implantation. The terminal differentiation of superficial urothelial cells has a key role because of the barrier function of these cells against urine. The aim of this study was to determine optimized conditions for the creation of terminally differentiated urothelium to cover large membrane surfaces. This can bring us closer to the goal of using functioning tissue constructs in clinical trials.