Biofabricated Structures Reconstruct Functional Urinary Bladders in Radiation-Injured Rat Bladders

Abstract

The ability to repair damaged urinary bladders through the application of bone marrow-derived cells is in the earliest stages of development. We investigated the application of bone marrow-derived cells to repair radiation-injured bladders. We used a three-dimensional bioprinting robot system to biofabricate bone marrow-derived cell structures. We then determined if the biofabricated structures could restore the tissues and functions of radiation-injured bladders. The bladders of female 10-week-old Sprague-Dawley (SD) rats were irradiated with 2-Gy once a week for 5 weeks. Adherent and proliferating bone marrow-derived cells harvested from the femurs of male 17-week-old green fluorescence protein-transfected Tg-SD rats were cultured in collagen-coated flasks. Bone marrow-derived cell spheroids were formed in 96-well plates. Three layers of spheroids were assembled by the bioprinter onto a 9 × 9 microneedle array. The assembled spheroids were perfusion cultured for 7 days, and then the microneedle array was removed. Two weeks after the last radiation treatment, the biofabricated structures were transplanted into an incision on the anterior wall of the bladders (n = 10). Control rats received the same surgery but without the biofabricated structures (sham-structure, n = 12). At 2 and 4 weeks after surgery, the sham-structure control bladder tissues exhibited disorganized smooth muscle layers, decreased nerve cells, and significant fibrosis with increased presence of fibrosis-marker P4HB-positive cells and hypoxia-marker hypoxia-induced factor 1α (HIF1α)-positive cells. The transplanted structures survived within the recipient tissues, and blood vessels extended within them from the recipient tissues. The bone marrow-derived cells in the structures differentiated into smooth muscle cells and formed smooth muscle clusters. The recipient tissues near the transplanted structures had distinct smooth muscle layers and reconstructed nerve cells, and only minimal fibrosis with decreased presence of P4HB- and HIF1α-positive cells. At 4 weeks after surgery, the sham-structure control rats exhibited significant urinary frequency symptoms with irregular and short voiding intervals, and low micturition volumes. In contrast, the structure-transplanted rats had regular micturition with longer voiding intervals and higher micturition volumes compared with the control rats. Furthermore, the residual volume of the structure-transplanted rats was lower than for the controls. Therefore, transplantation of biofabricated bone marrow-derived cell structures reconstructed functional bladders.

Impact of low‐dose tadalafil on adverse events after low‐dose‐rate brachytherapy for prostate cancer: A bi‐center randomized open‐label trial

“…Although bladder dysfunction after extracorporeal irradiation of the urinary bladder has been investigated in previous basic research studies, animal models of LUTS induced by irradiation of implanted seeds have not yet been established. [12][13][14][15][16][17][18][19] However, LDR may have similar effects to those of extracorporeal irradiation of the lower urinary tract. In animal models, extracorporeal irradiation damage to the urinary bladder leads to pathological change in three phases.…”

“…In animal models, extracorporeal irradiation damage to the urinary bladder leads to pathological change in three phases. [12][13][14][15][16][17][18][19] The first phase is acute damage consisting of urothelial swelling, ulceration, and vascular endothelial cell damage. 13,14 The second phase is the infiltration of inflammatory cells, 13,15 and the third phase is chronic and is associated with collagen deposition, development of fibrosis, and reduction in blood flow.…”

Recovery of cryo-injured rabbit urethras by biofabricated C-shaped adipose-derived mesenchymal cell structures

“…The process holds promise for diseases and injuries that are currently difficult to treat due to lack of suitable therapies. In this study, we used a 3D-bioprinter to biofabricate structures from AMC-derived spheroids (Imamura et al, 2018; Moldovan et al, 2017). The structures were of a suitable size, shape, and autologous cellular composition to be transplanted into the cryo-injured urethras of rabbits.…”

“…Biofabrication of the AMC structures was performed on a 3D-bioprinter (Regenova, Cyfuse Biomedical K.K., Tokyo, Japan) designed to create 3D-structures consisting only of cells (Imamura et al, 2018; Moldovan et al, 2017). Briefly, single spheroids, which were composed of the PKH26-labeled AMCs, were recovered from each well of the 96-well plates, and mounted on a custom designed, C-shaped 9×9 microneedle array.…”

“…The most serious limitation is the low survival rate of the injected cells in the recipient tissues. Previously, we reported that biofabricated structures improve cell survival rates during harvesting and handling and in the recipient tissues (Imamura et al, 2018; Moldovan et al, 2017). In this study, we designed novel biofabricated structures composed of adipose-derived mesenchymal cells (AMCs) and constructed them with a three-dimensional (3D)-bioprinter.…”