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Introduction: Repairing damaged cartilage poses significant challenges, particularly in cases of congenital cartilage defects such as microtia or congenital tracheal stenosis, or as a consequence of traumatic injury, as the regenerative potential of cartilage is inherently limited. Stem cell therapy and tissue engineering offer promising approaches to overcome these limitations in cartilage healing. However, the challenge lies in the size of cartilage-containing organs, which necessitates a large quantity of cells to fill the damaged areas. Therefore, pluripotent stem cells that can proliferate indefinitely are highly desirable as a cell source. This study aims to delineate the differentiation conditions for cartilage derived from human embryonic stem cells (ESCs) and to develop an automated cell culture system to facilitate mass production for therapeutic applications. Methods: Cartilage cell sheets were derived from human ESCs (SEES2, clinical trial-compatible line) by forming embryoid bodies (EBs) with either conventional manual culture or a benchtop multi-pipetter and an automated medium exchange integrated cell incubator, using xeno-free media. Cell sheets were implanted into the subcutaneous tissue of immunodeficient NOG mice to obtain cartilage tissue. The properties of cartilage tissues were examined by histological staining and quantitative PCR analysis. Results: We have optimized an efficient xeno-free system for cartilage production with the conventional culture method and successfully transitioned to an automated system. Differentiated cartilage was histologically uniform with cartilage-specific elasticity and strength. The cartilage tissues were stained by Alcian blue, safranin O, and toluidine blue, and quantitative PCR showed an increase in differentiation markers such as ACAN, COL2A1, and Vimentin. Automation significantly enhanced the efficiency of human ESC-derived chondrocyte differentiation. The number of constituent cells within EBs and the seeding density of EBs were identified as key factors influencing chondrogenic differentiation efficiency. By automating the process of chondrogenic differentiation, we achieved scalable production of chondrocytes. Conclusions: By integrating the differentiation protocol with an automated cell culture system, there is potential to produce cartilage of sufficient size for clinical applications in humans. The resulting cartilage tissue holds promise for clinical use in repairing organs such as the trachea, joints, ears, and nose.

Introduction: In cartilage regenerative medicine, transplanted chondrocytes contain a mixture of populations, that complicates the regeneration of uniform cartilage tissue. Our group previously reported that chondrocytes with higher chondrogenic ability could be enriched by selection of rapidly growing cells. In this study, the detailed properties of rapidly growing chondrocytes were examined and compared to slowly growing cells. Methods: Human auricular chondrocytes were fluorescently labeled with carboxyfluorescein succinimidyl ester (CFSE) and analyzed using flow cytometry, focusing on division rates as indicated by fluorescence intensity and cell morphology according to the forward scatter and side scatter. Rapid and slow growing cell groups were harvested on days 2 and 4 after CFSE labeling, and their ability to produce cartilage matrix in vitro was examined. To compare the chondrogenic ability in vivo, the cells were seeded on poly-l-lactic acid scaffolds and transplanted into nude mice. Gene expression differences between the rapid and slow cell groups were investigated by microarray analysis. Results: On day 2 after CFSE labeling, the rapidly growing cell group showed the highest proliferation rate. The results of pellet culture showed that the rapid cell group produced more glycosaminoglycans per cell than the slow cell group. The amount of glycosaminoglycan production was highest in the rapid cell group on day 2 after CFSE labeling, indicating high chondrogenic ability. Furthermore, microarray, gene ontology, and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed upregulation of genes that promote cell division such as origin recognition complex subunit 1 and downregulation of genes that inhibit cell division such as cyclin dependent kinase inhibitor 1A. Besides cell cycle-related genes, chondrocyte-related genes such as serpin family B member 2, clusterin, bone morphogenetic protein 2, and matrix metalloproteinase 3 were downregulated, while fibroblast growth factor 5 which is involved in stem cell maintenance, and coiled-coil and C2 domain containing 2A, which is required for cilia formation, were upregulated. Conclusion: The results showed that the rapid cell group proliferated well and had more undifferentiated properties, suggesting a higher stemness. The present findings provide a basis for the use of the rapid cell group in cartilage regeneration.

Afferent loop obstruction (ALO) is a rare complication of Kasai portoenterostomy (KPE) for biliary atresia. A 23-year-old Japanese woman who had undergone KPE with Roux-en-Y reconstruction for biliary atresia at age 42 days experienced intermittent abdominal pain during pregnancy. From computed tomography findings, she was diagnosed with ALO of the Roux-en-Y limb due to obstruction at the jejunojejunostomy. At 22 weeks of gestation, we inserted an endoscopic nasobiliary drainage (ENBD) tube into the dilated Roux-en-Y limb during double-balloon small-bowel endoscopy for treatment of the ALO. As no findings of jejunojejunostomy obstruction were evident during the endoscopy, we consider the obstruction was caused by flexion of the jejunojejunostomy associated with pregnancy. The ENBD tube afforded good drainage, and decompression of the Roux-en-Y limb was confirmed. We waited until 28 weeks of gestation to remove the ENBD tube, considering both the durability of ENBD tube and continued safety of the fetus. At 39 weeks of gestation, the patient delivered of a live baby boy (2,864 g) via vaginal delivery. ENBD tube insertion could be a minimally invasive option for treating ALO during pregnancy after KPE with Roux-en-Y reconstruction.

Objective: There are several approaches to pyloromyotomy for the treatment of hypertrophic pyloric stenosis including open transumbilical pyloromyotomy and laparoscopic pyloromyotomy. Beginning in 2012, we adopted intraumbilical longitudinal incision as a new transumbilical approach for pyloromyotomy. We describe details of the operative technique and results of this new approach. Methods: We reviewed records of patients undergoing transumbilical pyloromyotomy from 2005 to 2018. Perioperative outcomes were compared between intraumbilical longitudinal incision and supraumbilical incision, the latter of which is the conventional incision for transumbilical pyloromyotomy. Results: Twenty-four patients underwent pyloromyotomy with intraumbilical longitudinal incision (intraumbilical group) and 28 patients with supraumbilical incision (supraumbilical group). The median operative time was longer in the intraumbilical group (58.0 vs. 43.5 min, p = 0.002). However, the time to full feeding did not differ significantly between the two groups, and the median postoperative stay was shorter in the intraumbilical group (3 vs. 5.5 days, p = 0.003). There was no difference in the rate of complications (4.2% vs. 7.1%, p = 1.0). Scars after intraumbilical longitudinal incision were localized inside the umbilicus. Conclusion: Pyloromyotomy can be performed through intraumbilical longitudinal incision as safely as supraumbilical incision and intraumbilical longitudinal incision may improve cosmetic results. This approach can be an alternative technique for pyloromyotomy. [ABSTRACT FROM AUTHOR]