Norbert Schlote

TIME DEPENDENT SMOOTH MUSCLE REGENERATION AND MATURATION IN A BLADDER ACELLULAR MATRIX GRAFT: HISTOLOGICAL STUDIES AND IN VIVO FUNCTIONAL EVALUATION

PURPOSE We evaluated the time dependence of smooth muscle regeneration and restoration of in vivo functional properties in bladder augmented with a bladder acellular matrix graft. MATERIALS AND METHODS A total of 45 Sprague-Dawley rats underwent augmentation cystoplasty with a bladder acellular matrix graft. Two rats each were sacrificed at various intervals within the first 21 days and 6 each were sacrificed at 4, 8 and 12 weeks. This second group underwent preoperative and postoperative assessment of bladder function, including cystometry, electrostimulation and stimulation with ice water, potassium and carbachol, as well as labeling of the bladder wall by the injection of fluorescent microspheres. After sacrifice slides of the bladders prepared for hematoxylin and eosin, trichrome, KI67, vimentin, desmin, smooth muscle specific alpha-actin and fluorescent microspheres were evaluated. RESULTS Within 2 weeks the number of cells in the matrix as well as the proliferation index increased rapidly and then decreased gradually. Erythrocytes and inflammatory cells were found in the matrix within 2 to 4 days, followed by fibroblasts. A bladder host-to-matrix shift was evident by the appearance of microspheres in the matrix. Cell marker expression indicated the early appearance of vimentin and alpha-actin within the first 10 days. Distinct desmin expression was observed later, when the first smooth muscle cells were recognized. Functional evaluation revealed restored bladder function at 12 weeks. CONCLUSIONS The time dependent increase of muscle cell markers during smooth muscle cell regeneration in a bladder acellular matrix graft is concordant with the progressive restoration of bladder function. These results may support the bladder acellular matrix graft concept for clinical application.

The bladder acellular matrix graft in a rat chemical cystitis model: functional and histologic evaluation.

PURPOSE We investigated the feasibility of augmentation in a diseased bladder with a bladder acellular matrix graft. MATERIALS AND METHODS In 50 female Sprague-Dawley rats chemical cystitis was induced by intravesical instillation of HCl repeated monthly to maintain chronic inflammation. Urodynamic studies were performed in all rats 1 week after the induction of chemical cystitis and repeated at sacrifice. The 29 rats in the experimental group underwent partial cystectomy (50% or greater), followed by bladder acellular matrix graft augmentation, while the 21 controls underwent monthly HCl instillation only. The rats were sacrificed at 2 weeks, 1, 2 and 3 months, respectively. The bladder was removed and examined for histological changes. RESULTS Urodynamic studies showed that bladder capacity and compliance were significantly higher in the grafted than in the control group (p = 0.008 and 0.006, respectively, at 3 months). Histological studies revealed urothelial and smooth muscle regeneration within the bladder acellular matrix graft at 1 month and nerve regeneration at 3. The number of mast cells was significantly lower in the grafted region than in the host bladder of all grafted rats (p <0.001). CONCLUSIONS In this rat chemical cystitis model bladder augmentation with a bladder acellular matrix graft led to functional and histological improvement over diseased host bladder.

Tunica albuginea acellular matrix graft for penile reconstruction in the rabbit: a model for treating Peyronie's disease

Objective To evaluate the use of an acellular matrix graft of the tunica albuginea for functional penile reconstruction in severe cases of Peyronies disease.

Homologous acellular matrix graft for vaginal repair in rats: a pilot study for a new reconstructive approach.

Abstract. The purpose of this paper is to investigate using an acellular matrix graft of vagina (VAMG) or bladder (BAMG) in vaginal reconstruction. In 18 rats, vaginal length was measured and a hysterectomy performed. In three control animals, the vaginal stump was closed. In eight rats, the vagina was augmented with a VAMG; in seven, a BAMG was used. After 2–12 weeks, the animals were sacrificed, the vaginal length was reevaluated, and the vaginas were prepared for histologic evaluation. In the controls, the vagina was markedly shorter postoperatively. In the grafted animals, vaginal length was not significantly less than preoperative values with either matrix. Epithelialization, vascularization, and α-actin expression in the grafts were consistently observed. Regeneration appeared to be slightly greater in the organ-specific vagina matrix. With either matrix, however, although the vaginal stump remained open, the grafts lost most of the lumen. Vaginal reconstruction with a vagina acellular matrix graft is technically feasible. If further experiments can address the problem of luminal collapse – with, for instance, tissue expanders in the matrix – this technique may offer an alternative to the complex therapeutic options currently available.

Computer-assisted evaluation of the smooth-muscle electromyogram of the Corpora cavernosa by fast Fourier transformation

OBJECTIVE The aim of our study was to investigate analogous and digital recording of corpus cavernosum EMGs (CC-EMGs) in normal men according to criteria that were recently agreed upon in an international consensus workshop. METHODS CC-EMGs were analogously and digitally registered from 37 normal subjects. Power spectra in the frequency domain were determined via fast Fourier transformation (FFT). RESULTS Thirty-one of men showed identical or at least very similar electrical activity patterns in the analogous and digital registration. Needle penetration artifacts (investigated in 18 subjects) were found in 17/18 CC-EMGs during the first 20 min. Power spectra show a maximum of power at a frequency of 0.3 Hz with more than 90% of the power located between 0 and 5 Hz. CONCLUSIONS Registration of CC-EMGs in normal men resulted in interindividually reproducible recordings. Age hardly affected CC-EMGs. Computer-assisted evaluation by FFT after elimination of artifacts was feasible. Thus, interpretation of the CC-EMG signals by a computer-aided expert system seems to be promising for clinical routine, in particular with respect to an increase in objectivity and a decrease in time needed for interpretation.

Functional tissue engineering of autologous tunica albuginea: A possible graft for peyronie's disease surgery

OBJECTIVES The aim of the present study was to generate a tissue engineered type of mechanically stable graft suitable for surgical replacement of the tunica albuginea penis. METHODS Porcine fibroblasts isolated from open fascia biopsies were seeded on decellularized collagen matrices and then cultivated in a bioreactor under continuous multiaxial stress for up to 21 days (n=12). Static cultures without mechanical stress served as controls. Cell proliferation, cell alignment, and de novo synthesis of extracellular matrix proteins (proteoglycans, procollagen I, elastin) in these grafts was evaluated by hematoxylin-eosin, pentachrome, and immuno-staining. Additionally, the enzymatic isolation of porcine fibroblasts from X4mm skin punch biopsies (n=8) was evaluated. RESULTS Mechanically strained cultures of fibroblasts showed a homogeneous multilayer matrix infiltration and a regular cell alignment in the direction of strain axis after 7 days, as well as a de novo production of extracellular matrix proteins compared to the static control. A large amount of viable fibroblasts was easily obtained from small skin punch biopsies. CONCLUSION This study shows that continuous multiaxial stimuli improve proliferation and extracellular matrix synthesis of mature fibroblasts reseeded on a biological matrix making this a feasible autologous tissue engineered graft for penile surgery. For the clinical setting fibroblasts harvested from small skin biopsies can be a comfortable cell source.