The advent of three-dimensional printing (3DP) technology has enabled the creation of a tangible and complex 3D object that goes beyond a simple 3D-shaded visualization on a flat monitor. Since the early 2000s, 3DP machines have been used only in hard tissue applications. Recently developed multi-materials for 3DP have been used extensively for a variety of medical applications, such as personalized surgical planning and guidance, customized implants, biomedical research, and preclinical education. In this review article, we discuss the 3D reconstruction process, touching on medical imaging, and various 3DP systems applicable to medicine. In addition, the 3DP medical applications using multi-materials are introduced, as well as our recent results.

Cyclophosphamide (CP) causes extensive cystitis, which is ameliorated with concomitant treatment with mesna. We investigated the protective mechanisms of mesna in the expression of uroplakin (UP), a strong mucosal barrier against toxic materials, in CP-induced rat cystitis. A total of 54 SD female rats received a single intraperitoneal injection of 200 mg of CP/kg. Six CP-treated, 6 CP + mesna (120 mg/kg)-treated rats, and 6 negative controls were sequentially sacrificed at 12, 24, and 72 h post-CP injection. The bladders were harvested. The levels of UPIa, Ib, II, and III mRNA on real-time PCR, the UPII and III expressions on immunoblotting, and the UPII expression on immunolocalization study in the harvested bladder were maximally suppressed within 12-24 h, whereas partially or completely recovered at 24-72 h post-CP injection. In addition, the responses in UPs after a CP insult were heterogeneous (i.e., markedly suppressed in UPII and lesser destructive in UPIII). Even though the mesna-treated rats also showed transient and small reductions in the mRNA levels of all UPs, mesna clearly preserved the UP expressions of mRNA and protein in CP-induced urinary bladder mucosa. In conclusion, this study suggests that CP transiently reduces the expression of UPs and mesna protects the urinary bladder mucosa through the preservation of UPs protein.

We investigated the attenuated effect of intravesical epinephrine (EPI) on uroplakin II (UPII) expression in cyclophosphamide (CYP)-induced rat cystitis. Sixty-eight Sprague-Dawley female rats were divided into one negative control group (GI) and five intraperitoneally CYP (150 mg CYP/kg)-injected groups (GII-VI) consisting of a positive control group (GII), three groups (GIII-V) with retaining intravesically instillated ameliorating agents for 90 min by urethral ligation until sacrifice, and one group (GVI) with freely voiding after intravesical EPI instillation. The retention groups were further classified into null-treated- (GIII), EPI- (GIV), and vehicle group (GV). All rats were euthanized 24 h after CYP injection. The UPII and α1-adrenergic receptors (AR) levels were measured with real-time polymerase chain reaction (RT-PCR) method and the morphological changes were also evaluated. CYP induced severe cystitis and decreased vesical UPII mRNA level. The EPI-treated groups had showed attenuation effects against submucosal edema and hemorrhage, and preserved UPII expression. Concurrently, intravesical EPI resulted in a significant preservation of both subtypes of α1A- and α1B AR expressions, which was well correlated with the hemostatic pattern in the samples. The obstructed and null-treated group (GIII) revealed severe cystitis and maximally decreased UPII levels, and the diluting effect of vehicle (GV) on CYP toxicity was insignificant on UPII preservation. The UPII level of RT-PCR was well correlated with the UPII immunohistological expression and their morphological changes. Intravesical instillation of EPI preserves UPII expression and attenuates the toxic responses in the bladder in CYP-induced rat cystitis.