Scaffold-free bone-like 3D structure established through osteogenic differentiation from human gingiva-derived stem cells.

Introduction & objectives: Stem cell therapy for regenerative medicine has been sincerely investigated, but not still popular although some clinical trials show hopeful results. This therapy is suggested to be a representative candidate such as bone defect due to the accident, iatrogenic resection oncological tumor, congenital disease, and severe periodontitis in oral region. Recently, the Bio-3D printer "Regenova®" has been introduced as an innovative three-dimensional culture system, equipped scaffold-free bio-assembling techniques without any biomaterials. Therefore, we expected a mount of bone defect could be repaired by the structure established from this Bio-3D printer using osteogenic potential stem cells. Material & methods: The gingival tissue (1x1 mm) was removed from the distal part of the lower wisdom tooth of the patients who agreed our study. Human Gingival Mesenchymal Stem Cells (hGMSCs) were isolated from this tissue and cultured, since we confirmed the characteristics such as facile isolation and accelerated proliferation, further, strong potential of osteogenic-differentiation. Spheroids were formed using hGMSC in 96-well plates designed for low cell adhesion. The size of the spheroids was measured, and fluorescent immunostaining was employed to verify the expression of stem cell and apoptosis marker, and extracellular matrix. Following four weeks of bone differentiation, µCT imaging was performed. Calcification was confirmed by alizarin red and von Kossa staining. Fluorescent immunostaining was utilized to assess the expression of markers indicative of advanced bone differentiation. Results: We have established and confirmed the spheroids (∼600 µm in diameter) constructed from human GMSCs (hGMSCs) still maintain stem cell potentials and osteogenic differentiation abilities from the results that CD73 and not CD34 were expressed as stem cell positive and negative marker, respectively. These spheroids were pilled up like cylindal shape to the "Kenzan" platform of Bio-3D printer and cultured for 7days. The cylindal structure originated from compound spheroids were tried to differentiate into bone four weeks with osteogenic induction medium. The calcification of bio-3D printed bone-like structures was confirmed by alizarin red and Von Kossa staining. In addition, µCT analysis revealed that the HU (Hounsfield Unit) of the calcified structures was almost identical to that of trabecular bone. Immunofluorescent staining detected osteocalcin expression, a late-stage bone differentiation marker. Conclusion: For the first time, we have achieved the construction of a scaffold-free, bone-like luminal structure through the assembly of spheroids comprised of this hGMSCs. This success is sure to be close to the induction of clinical application against regenerative medicine especially for bone defect disease.

Correlation between extended pelvic lymph node dissection and urinary incontinence at early phase after robot-assisted radical prostatectomy.

OBJECTIVES: To investigate the impact of extended pelvic lymph node dissection (ePLND) on urinary incontinence (UI) at early post-surgery robot-assisted radical prostatectomy (RARP). METHODS: Patients who underwent RARP without cavernous nerve sparing were included between 2014 and 2019. Patient data were obtained prospectively. The associations between ePLND and postoperative urinary continence were defined as a maximum of one daily pad use. International prostate symptom score (IPSS) was examined. Expression of synaptophysin and tyrosine hydroxylase (TH) in perilymph node adipose tissue (PLA) was evaluated by immunohistochemistry. RESULTS: In total, 186 and 163 patients underwent RARP with and without ePLND. Urinary continence rate at 1 month postoperatively among patients with ePLND was lower than those without ePLND (24.1% vs. 35.1%, p < 0.05), however, not significantly different at 3, 6, and 12 months after RARP (57.4 vs. 62.6%, 73.1 vs. 74.2%, and 83.0 vs. 81.2%, respectively). Total and voiding plus postvoiding IPSS scores at 1 month were higher in patients with ePLND than in those without ePLND (14.5 ± 0.5 vs. 13.6 ± 0.6, 7.0 ± 0.3 vs. 6.2 ± 0.4, respectively, p < 0.05). In univariate and multivariate analyses, larger prostate volume and ePLND were factors associated with an increased UI rate. Among patients who underwent ePLND, synaptophysin and TH-positive nerve fibers were detected in PLA. CONCLUSIONS: Detection of synaptophysin and TH-immunopositive nerves suggested denervation of sympathetic and peripheral nerves caused by ePLND might be associated with a higher UI rate and poor urinary symptoms at an early stage after RARP.