Background : Urethral tissue damage can cause stress urinary incontinence or urinary retention, and there are few long-term, effective treatments. For structural and functional recovery of urethral tissues, we designed and constructed C-shaped structures composed of adipose-derived mesenchymal cells (AMCs) by using a three-dimensional (3D)-bioprinter system, which could be transplanted in damaged urethras without obstructing the lumen.
Methods : AMCs were harvested from New Zealand White rabbits, labeled with PKH26 for later identification, and cultured to form spheroids. The spheroids were assembled on a custom-designed C-shaped support by a three-dimensional bioprinter, and perfusion cultured for 7 days. Urethras of female rabbits were cryo-injured by spraying with liquid nitrogen for 20 seconds. The damaged region was incised, and the biofabricated structure was autologously transplanted into the cryo-injured region (n＝4). Control rabbits were treated similarly but without transplantation of a C-shaped structure (n＝4). Two and four weeks after surgery, the urethras were harvested for analyses.
Results : Prior to transplantation, the AMCs within the biofabricated structures expressed mesenchymal cell markers and extracellular matrices. Two and four weeks after surgery, the control urethras were partially constricted ; however, the structure-transplanted urethras were patent. The AMCs within the structures had differentiated into skeletal muscle, smooth muscle, or nerve cells. Some cells contained growth factors and cytokines. In addition, they expressed decreased fibroblast markers, hypoxia markers, and apoptotic markers.
Conclusions : The transplantation of biofabricated C-shaped AMC structure has the potential to be an effective treatment for urethral recovery due to enhanced reconstruction of muscle, and nerve cells.

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The aim of this study was to examine the status of cancer patients in the adolescent and young adult (AYA) population in Nagano Prefecture, using data from the hospital-based cancer registry (HBCR). Patients in the AYA population (15-39 years of age) included in the HBCR from January 2016 to December 2018 in Nagano Prefecture were analyzed in this study.
Results ; A total of 1640 (male : 386, female : 1254) were enrolled. The number of registered patients markedly increased over the age of 25 and 70％ of patients were observed at 30-39 years old. The distribution of cancer types in AYA was dependent on age and sex. The increased numbers were due to the increase in breast and cervical cancer in females. Most cases of cervical cancer were detected in early stages and by health screening, but the frequency of advanced staged breast cancer (stage IV) in the AYA population was similar to that in non-AYA population breast cancer and 70％ of breast cancer was detected not by health screening but mainly by symptoms in Nagano Prefecture. In addition, the frequency of spinal-brain tumor in Nagano Prefecture was relatively higher compared with that in national HBCR data in Japan.
Such information provides an overview of AYA cancer and reveals that a substantial number of AYA are diagnosed every year in Nagano Prefecture. Hospital-based cancer registries can be powerful tools for evaluating the epidemiology of cancer in Nagano Prefecture.

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