Kan Suzuki

An animal model study for tissue-engineered trachea fabricated from a biodegradable scaffold using chondrocytes to augment repair of tracheal stenosis

INTRODUCTION We have designed an engineered graft fabricated from a biodegradable scaffold using chondrocytes and applied this construct to augment repair of tracheal stenosis. This study investigated the feasibility of using such tissue-engineered airways with autologous chondrocytes in a rabbit model. MATERIAL AND METHODS Chondrocytes were isolated and expanded from the auricular cartilage of New Zealand white rabbits, then seeded onto composite 3-layer scaffolds consisting of a collagen sheet, a polyglycolic acid mesh, and a copolymer (l-lactide/epsilon-caprolactone) coarse mesh. The engineered grafts were implanted into a 0.5 x 0.8-cm defect created in the midventral portion of the cervical trachea. Gelatin sponges that slowly released basic fibroblast growth factor (b-FGF) were then placed on the constructs, which were retrieved 1 or 3 months after implantation. RESULTS The biodegradable scaffold seeded with chondrocytes could maintain airway structure up to 3 months after implantation. Tracheal epithelial regeneration occurred in the internal lumen of this composite scaffold. Three months after implantation, staining of the sections showed cartilage accumulation in the engineered tracheal wall. CONCLUSION This composite biodegradable scaffold may be useful for developing engineered trachea. A gelatin sponge slowly releasing b-FGF might enhance chondrogenesis.

In vitro organogenesis from undifferentiated cells in Xenopus

Amphibians have been used for over a century as experimental animals. In the field of developmental biology in particular, much knowledge has been accumulated from studies on amphibians, mainly because they are easy to observe and handle. Xenopus laevis is one of the most intensely investigated amphibians in developmental biology at the molecular level. Thus, Xenopus is highly suitable for studies on the mechanisms of organ differentiation from not only a single fertilized egg, as in normal development, but also from undifferentiated cells, as in the case of in vitro organogenesis. Based on the established in vitro organogenesis methods, we have identified many genes that are indispensable for normal development in various organs. These experimental systems are useful for investigations of embryonic development and for advancing regenerative medicine. Developmental Dynamics 238:1309–1320, 2009.

A Female Infant Who Had both Complete VACTERL Association and MURCS Association : Report of a Case

A 41-day-old female infant with VACTERL association was transferred to the pediatric intensive care unit of our hospital. She had been delivered at 36 weeks gestation by spontaneous vaginal delivery and weighed 2340 g. Esophageal atresia type A with long gap, anal atresia, cardiac anomaly (atrial septal defect and patent ductus arteriosus), thoracic vertebral dysplasia, left renal agenesis, and minor anomalies (left-side facial nerve palsy, left-side difficulty in hearing, and the absence of the right thenar) had been diagnosed by various examinations. She was transferred to our hospital to receive treatment for heart failure due to a cardiac anomaly. We recognized vaginal atresia during a radical operation for anal atresia (rectovestibular fistula) at 8 months of age. Furthermore, magnetic resonance imaging (MRI) revealed agenesis of the uterus. MURCS association includes Mullerian duct aplasia or hypoplasia, renal aplasia, and cervicothoracic somite dysplasia. This is the first case of complete VACTERL association combined with MURCS association.

Long-Term Survival of a Baby with Body Stalk Anomaly: Report of a Case

Body stalk anomaly is characterized by severe scoliosis, severe pulmonary hypoplasia, and giant omphalocele. The prognosis of the disease is poor and most obstetricians consider it fatal. Very few patients with body stalk anomaly survive. We report the case of a baby diagnosed with body stalk anomaly in fetal life, who was saved by intensive care after birth. We closed the giant omphalocele successfully by placing karaya gum sheets over it, which created a humidified environment and promoted natural skin epithelization over the skin defect.

XRASGRP2 is essential for blood vessel formation during Xenopus development.

Ras guanyl nucleotide-releasing protein 2 (RASGRP2), one of the Ras guanine exchange factors, is implicated as a critical regulator of inside-out integrin activation in human lymphocytes, neutrophils and platelets. However, the activities of this protein in endothelial cells remain unclear. In the current study, we identify a physiological function in blood vessel formation for XRASGRP2, which is the Xenopus ortholog of mammalian RASGRP2. XRASGRP2 over-expression induced ectopic vascular formation, and XRASGRP2-knockdown embryos showed delayed vascular development. We also investigated the upstream signaling of XRASGRP2 in endothelium formation. XRASGRP2 expression was up-regulated in the presence of VEGF-A and down-regulated following VEGF-A depletion. XRASGRP2 knockdown abolished the ectopic induction of endothelial cells by VEGF-A in the posterior ventral blood island. These results suggest that XRASGRP2 is essential for vascular formation during Xenopus development.

A Pilot Study of Laparoscopic Gastric Pull-Up by Using the Natural Orifice Translumenal Endoscopic Surgery Technique: A Novel Procedure for Treating Long-Gap Esophageal Atresia (Type A)

AIM This study aimed to develop a novel procedure for treating long-gap pure esophageal atresia. This procedure, which entails the combined use of laparoscopy and natural orifice translumenal endoscopic surgery (NOTES), would enable primary repair without cervical and thoracic incisions and prevent postoperative gastroesophageal reflux disease (GERD). METHODS Nonsurvival experiments were conducted in 9 pigs to study the technical feasibility. The procedure comprised the following: (1) creation of the disease model by laparoscopic resection of the lower esophagus; (2) laparoscopic fundoplication, complete mobilization of the stomach, and enlargement of the esophageal hiatus; (3) formation of a peroral transesophageal entry site into either the postmediastinum or the right thoracic cavity followed by fashioning a tunnel to the peritoneal cavity; (4) gastric pull-up by using both laparoscopy and NOTES; (5) esophagoesophageal anastomosis using BraceBar™, a prototype of the double T-bar suturing device (Olympus Medical Systems Co., Tokyo, Japan). RESULTS Laparoscopic procedures were performed without complications. The postmediastinal tunnel was successfully created three times with a complication of pleural injury. However, gastric pull-up via this route could not be completed due to porcine anatomical reasons. Gastric pull-up through the right thoracic route was achieved five times in six attempts. Two disorientations and a hemorrhagic death occurred during the procedures. CONCLUSIONS This study showed that combined use of laparoscopy and NOTES enabled gastric pull-up without cervical and thoracic incisions. Our method has the potential of lowering the incidence of GERD and enabling primary repair of this disease.

Slow release of basic fibroblast growth factor (b-FGF) promotes growth of tracheal cartilage ☆

PURPOSE Tracheomalacia is a major cause of morbidity in conditions such as oesophageal atresia. However, symptoms usually improve with age. A more rapid growth of tracheal cartilage can be induced by basic-Fibroblast Growth Factor (b-FGF). This study aimed to investigate whether slow-release b-FGF could act as a novel treatment for tracheomalacia. METHODS Biodegradable gelatin hydrogel sheets incorporating 0.5, 5, or 50 μg/20 μl of b-FGF solution were inserted between the cervical trachea and esophagus of rats. No intervention was performed in rats in a control group. All animals were sacrificed 4 weeks later, and the luminal area of the cervical trachea and the thickness of the cartilage were measured. RESULTS The mean luminal areas in the control group and in the b-FGF groups were 3.1, 3.2, 3.8, and 2.6mm(2), respectively, and showed a peak area at 5 μg of b-FGF. A significant difference was seen only between the control group and the b-FGF 5 μg group (p<0.05). The mean thickness of the tracheal cartilage was 0.12, 0.13, 0.19, and 0.32 mm in the control and the b-FGF groups, respectively, and showed a dose-dependent increase, which was statistically significant between the b-FGF 5 μg or 50 μg groups and the control group (p<0.01). CONCLUSION This study showed that slow-release b-FGF enlarges the tracheal lumen and thickens the cartilage in a dose-dependent fashion.

Plasma citrulline may be a good marker of intestinal functions in intestinal dysfunction.

Plasma citrulline has been reported to be a good indicator of intestinal functional volume in patients with intestinal dysfunction. We reconfirmed the facts and also investigated the dynamic changes of plasma citrulline in acute‐phase patients with intestinal dysfunction.

Interleukin 6 and interleukin 8 play important roles in systemic inflammatory response syndrome of meconium peritonitis

PurposeMeconium peritonitis is caused by an intestinal perforation that may occur in the fetus, followed by severe chemical peritonitis, resulting in high morbidity.MethodsWe have experienced six patients with meconium peritonitis. Cystic drainage was performed soon after birth for all patients. We investigated the concentrations of several cytokines and a chemokine (interleukin 8) in the ascites from the six patients with meconium peritonitis. In two patients we also measured the serum cytokines and chemokine level just after birth.ResultsInterleukin 6 and interleukin 8 concentrations were very high in the cyst or ascites just after birth. In the serum taken from two patients, the levels of interleukin 6 and interleukin 8 were also high. In five patients who underwent drainage of cysts after birth, systemic inflammation could not be completely suppressed before curative surgery.ConclusionsInterleukin 6 and interleukin 8 play important roles in the inflammatory response syndrome associated with meconium peritonitis, and drainage of cystic fluid did not completely suppress this inflammation. To lessen the high morbidity of meconium peritonitis, efforts should be made to suppress the inflammatory response using new treatment strategies, such as administration of steroids or anti-cytokine therapy to supplement cystic drainage.

Mosapride for gastroesophageal reflux disease in neurologically impaired patients

The prokinetic agent cisapride is effective for the treatment of gastroesophageal reflux disease (GERD) in infants and children, but is no longer used for this purpose because of safety concerns. Therefore, other pharmacological agents need to be investigated for efficacy in GERD treatment. In this study, we examined the effectiveness and safety of mosapride for the treatment of neurologically impaired children and adolescents with GERD.