Fabrication of Multi-Channel Nerve Guidance Conduits Containing Schwann Cells Based on Multi-Material 3D Bioprinting.

Nerve guidance conduits (NGCs) are an essential solution for peripheral nerve repair and regeneration in tissue engineering and medicine. However, the ability of current NGCs is limited to repairing longer nerve gap (i.e., >20 mm) because it cannot meet the following two conditions simultaneously: (1) directional guidance of the axial high-density channels and (2) regenerative stimulation of the extracellular matrix secreted by Schwann cells (SCs). Therefore, we propose a multi-material 3D bioprinting process to fabricate multi-channel nerve guide conduits (MNGCs) containing SCs. In the article, cell-laden methacrylate gelatin (GelMA) was used as the bulk material of MNGCs. To improve the printing accuracy of the axial channels and the survival rate of SCs, we systematically optimized the printing temperature parameter based on hydrogel printability analysis. The multi-material bioprinting technology was used to realize the alternate printing of supporting gelatin and cell-laden GelMA. Then, the high-accuracy channels were fabricated through the UV cross-linking of GelMA and the dissolving technique of gelatin. The SCs distributed around the channels with a high survival rate, and the cell survival rate maintained above 90%. In general, the study on multi-material 3D printing was carried out from the fabricating technology and material analysis, which will provide a potential solution for the fabrication of MNGCs containing SCs.

Prognostic value of programmed cell death ligand-1 expression in patients with bladder urothelial carcinoma undergoing radical cystectomy: A meta-analysis.

Background: Radical cystectomy and removal of pelvic lymph nodes (RC-PLND) is a recommended treatment for high-risk non-muscle-invasive and muscle-invasive non-metastatic bladder cancer (BC). However, 50% of patients relapse after RC-PLND. This study aimed to evaluate the effect of programmed cell death ligand-1 (PD-L1) on the prognosis of bladder urothelial carcinoma (BUC) after RC-PLND. Methods: We present this meta-analysis according to the Preferred Reporting Items for Systematic Review and Meta-Analyses Guidelines. The main outcomes were overall survival (OS), recurrence-free survival (RFS), and cancer-specific survival (CSS) of 3 and 5 years after RC-PLND. Results: Overall, 11 studies and 1393 BUC cases were included in our meta-analysis. In tumor cells (TCs), the PD-L1 negative group had statistically significant advantage in 5-year OS (risk ratio [RR]: 0.85, 95% confidence interval [CI]: 0.74-0.97, P = 0.02), RFS (RR: 0.76, 95% CI: 0.58-0.99, P = 0.04), and CSS (RR: 0.73, 95% CI: 0.58-0.92, P = 0.009) compared with the PD-L1 positive group. But, no statistically significant difference in 5-year OS and RFS was observed between the PD-L1 negative and positive groups in tumor-infiltrating immune cells. Conclusions: Our study found that patients with BUC who tested positive for PD-L1 in TCs had a poor prognosis after RC-PLND. PD-1 or PD-L1 inhibitors could be used as a adjuvant medication for patients with BUC after RC-PLND who exhibit PD-L1 overexpression in TCs. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42022301424.

A comprehensive gene expression profile analysis of prostate cancer cells resistant to paclitaxel and the potent target to reverse resistance.

Background: Paclitaxel resistance is the major clinical obstacle in the chemotherapy of prostate cancer (PCa), but the resistant mechanism is less investigated.Purpose: To establish two paclitaxel-resistant PCa cells, provide a comprehensive gene expression profile analysis of resistant cells and the potential target to reverse resistance.Methods: Two Paclitaxel-resistant PCa cells (PC3/PR, LNcap/PR) were established by gradually increasing drug concentration. MTT and transwell assays were performed to detect drug sensitivity, cell proliferation and migration abilities. RNA-Sequencing (RNA-seq) and bioinformatic analyses were performed to identify abnormally expressed genes (AEGs) in resistant cells, and annotate the biological functions of AEGs. The role of the candidate AEG, TLR-4, on the resistant phenotypes was further investigated.Results: The resistance index of resistant cells was 2-3, and they showed a slower proliferation and increased migration ability. 4741 AEGs were screened out (Log2fold change absolute: log2FC(abs) > 1) in the resistant cells, and they were enriched in 2'-5'-oligoadenylate synthetase activity and chemical carcinogenesis. A number of AEGs, CCND2, IGFBP3, FOS, SHH, ZEB2, and members of FGF, FGFR and WNT families were also identified to be involved in cancer- and resistant phenotype-related processes. Finally, TLR-4 was validated significantly increased in resistant cells, and knockdown of TLR-4 increased drug-sensitivity, inhibited the proliferation and migration abilities.Conclusions: The study provided a comprehensive gene expression profile of paclitaxel-resistant PCa cells, and TLR-4 could be a potential target to reverse paclitaxel resistance.

A novel prognostic model based on three clinic-related miRNAs for prostate cancer.

Background: Prostate cancer (PCa) is the second most common malignant tumor in men worldwide. MiRNAs have been reported to play significant roles in prognosis prediction for patients with malignant tumors. Methods: The survival-related miRNAs (sDMIRs) were identified by Cox regression analysis. A risk score model (RSM) was established based on three sDMIRs. The expression levels of sDMIRs in cell lines and clinical samples were detected via quantitative polymerase chain reaction. The correlations between sDMIRs and clinicopathological characteristics of PCa patients were evaluated using the chi-square test and Fisher's exact probability method. Results: Four sDMIRs were remarkably related to the prognosis of PCa patients based on univariate Cox analysis, of which miR-10a-5p, miR-20a-5p, and miR-508-3p were used to establish the RSM. The OS in the low-risk group was better than that in the high-risk group. In the verification of various prostate cell lines and clinical samples from 162 PCa patients, the prominently higher expression of miR-10a-5p and miR-20a-5p and lower expression of miR-508-3p were detected in PCa cell lines and tumor tissues, especially the more advanced T-stage. Besides, the higher expression of miR-20a-5p and miR-10a-5p was significantly correlated to the higher level of PSA, Gleason score, more advanced T-stage, and distant metastasis status. Conclusion: We identify and validate the clinical significance of three sDMIRs and establish a verified RSM to evaluate the prognosis for PCa patients. The findings not only provide a reliable tool for clinical decision-makers to evaluate patients' prognosis but also offer a novel perspective into the field of biomarker identification.

Establishment of a risk prediction model for postoperative constipation in patients with oral and maxillofacial malignant tumors / 口腔疾病防治

Objective@#To understand the incidence and influencing factors of postoperative constipation in patients with malignant tumors who undergo oral and maxillofacial surgery and construct a constipation risk prediction model to provide a reference for the prevention and treatment of postoperative constipation.@*Methods@#The data of 191 patients who underwent oral and maxillofacial malignant tumor surgery at the Affiliated Stomatological Hospital of Sun Yat sen University from June 2019 to June 2020 were analyzed retrospectively. The independent influencing factors were selected via univariate analysis and logistic multivariate regression analysis, a risk prediction nomogram was established, and the prediction model was evaluated by the area under the ROC curve. Both internal and external use the C index to verify the accuracy of the model. @*Results @#Among 191 patients, 52 (27.23%) had postoperative constipation. Univariate analysis showed that a preoperative secret history of defecation, total energy intake, tracheotomy, smoking, drinking, operation duration, bleeding volume, bed time, eating homogenate diet, sex, surgical repair method, use of probiotics, T-stage of cancer and food intake may be the influencing factors of postoperative constipation in patients with oral and maxillofacial malignant tumors (P<0.05). Multivariate analysis showed that repair method, bed time and sex were independent risk factors for postoperative constipation in patients with oral and maxillofacial malignant tumors (P<0.05). The repair method was a fibular myocutaneous flap with a long bed time, and male patients were prone to constipation after surgery. The c-index values in the training group and the verification group were 0.882 and 0.953, respectively. The area under the ROC curve of the training group was 0.909 (95%CI: 0.850-0.968), and the area under the ROC curve of the verification group was 0.893 (95%CI: 0.787-0.999). The nomogram showed good discrimination ability.@*Conclusion @#The repair method, bed time and sex are independent risk factors for postoperative constipation in patients with oral and maxillofacial malignant tumors. The risk prediction model has good discrimination ability.

Collagen-Based Thiol-Norbornene Photoclick Bio-Ink with Excellent Bioactivity and Printability.

As the essential foundation of bioprinting technology, cell-laden bio-ink is confronted with the inevitable contradiction between printability and bioactivity. For example, type I collagen has been widely applied for its excellent biocompatibility; however, its relatively low self-assembly speed restricts the performance in high-precision bioprinting of cell-laden structures. In this study, we synthesize norbornene-functionalized neutral soluble collagen (NorCol) by the reaction of acid-soluble collagen (Col) and carbic anhydride in the aqueous phase. NorCol retains collagen triple-helical conformation and can be quickly orthogonally cross-linked to build a cell-laden hydrogel via a cell-friendly thiol-ene photoclick reaction. Moreover, the additional carboxyl groups produced in the reaction of carbic anhydride and collagen obviously improve the solubility of NorCol in neutral buffer and miscibility of NorCol with other polymers such as alginate and gelatin. It enables hybrid bio-ink to respond to multiple stimuli, resulting in continuous cross-linked NorCol networks in hybrid hydrogels. For the first time, the collagen with a triple helix structure and gelatin can be mixed and printed, keeping the integrity of the printed construct after gelatin's dissolution. The molecular interaction among giant collagen molecules allows NorCol hydrogel formation at a low concentration, which leads to excellent cell spreading, migration, and proliferation. These properties give NorCol flexible formability and excellent biocompatibility in temperature-, ion-, and photo-based bioprinting. We speculate that NorCol is a promising bio-ink for emerging demands in tissue engineering, regenerative medicine, and personalized therapeutics.

Valve-based consecutive bioprinting method for multimaterial tissue-like constructs with controllable interfaces.

Bioprinting is a promising technology focusing on tissue manufacturing, whose vital problem is the precise assembly of multiple materials. As the primary solution, the extrusion-based multi-printhead bioprinting (MPB) method requires printhead switching during the printing process, which induces inefficient motion time and material interface defects. We present a valve-based consecutive bioprinting (VCB) method to resolve these problems, containing a precise integrated switching printhead and a well-matched voxelated digital model. The rotary valve built-in the VCB printhead guarantees the precise assembling of different materials at the interface isolated from the viscoelastic inks' elastic potential energy in the cartridge. We study the coordinated control approach of the valve rotation and pressure adjustment to achieve the seamless switching, leading to a controllable multimaterial interface, including boundary and suture structure. Furthermore, we compare the VCB method and MPB method, quantitatively and comprehensively, indicating that the VCB method obtained greater mechanical strength (maximum tensile deformation increased by 44.37%) and higher printing efficiency (effective time ratio increased by 29.48%). As an exemplar, we fabricate a muscle-like tissue with a vascular tree, suture interface encapsulating C2C12, and human dermal fibroblasts (HDFB) cells, then placed it in complete medium with continuous perfusion for 5 d. Our study suggests that the VCB method is sufficient to fabricate heterogeneous tissues with complex multimaterial interfaces.