Evaluation of safety and efficacy of autologous oral mucosa-derived epithelial cell sheet transplantation for prevention of anastomotic restenosis in congenital esophageal atresia and congenital esophageal stenosis

BACKGROUND

We performed the first autologous oral mucosa-derived epithelial cell sheet transplantation therapy in a patient with refractory postoperative anastomotic stricture in congenital esophageal atresia (CEA) and confirmed its safety. In this study, patients with CEA and congenital esophageal stenosis were newly added as subjects to further evaluate the safety and efficacy of cell sheet transplantation therapy.

METHODS

Epithelial cell sheets were prepared from the oral mucosa of the subjects and transplanted into esophageal tears created by endoscopic balloon dilatation (EBD). The safety of the cell sheets was confirmed by quality control testing, and the safety of the transplantation treatment was confirmed by 48-week follow-up examinations.

RESULTS

Subject 1 had a stenosis resected because the frequency of EBD did not decrease after the second transplantation. Histopathological examination of the resected stenosis revealed marked thickening of the submucosal layer. Subjects 2 and 3 did not require EBD for 48 weeks after transplantation, during which time they were able to maintain a normal diet by mouth.

CONCLUSIONS

Subjects 2 and 3 were free of EBD for a long period of time after transplantation, confirming that cell sheet transplantation therapy is clearly effective in some cases. In the future, it is necessary to study more cases; develop new technologies such as an objective index to evaluate the efficacy of cell sheet transplantation therapy and a device to achieve more accurate transplantation; identify cases in which the current therapy is effective; and find the optimal timing of transplantation; and clarify the mechanism by which the current therapy improves stenosis.

TRIAL REGISTRATION

UMIN, UMIN000034566, registered 19 October 2018, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000039393 .

First-in-human autologous oral mucosal epithelial sheet transplantation to prevent anastomotic re-stenosis in congenital esophageal atresia

Background

Congenital esophageal atresia postoperative anastomotic stricture occurs in 30–50% of cases. Patients with severe dysphagia are treated with endoscopic balloon dilatation (EBD) and/or local injection of steroids, but many patients continue to experience frequent stricture. In this study, we investigated the transplantation of autologous oral mucosa-derived cell sheets (epithelial cell sheets) as a prophylactic treatment for congenital esophageal atresia postoperative anastomotic stricture.

Methods

Epithelial cell sheets were fabricated from a patient’s oral epithelial tissue, and their safety was confirmed by quality control tests. The epithelial cell sheets were transported under controlled conditions from the fabrication facility to the transplantation facility and successfully transplanted onto the lacerations caused by EBD using a newly developed transplantation device for pediatric patients. The safety of the transplantation was confirmed by follow-up examinations over 48 weeks.

Results

The dates that EBD was performed were recorded for one year before and after epithelial cell sheet transplantation, and the intervals (in days) were evaluated. For about 6 months after transplantation, the intervals between EBDs were longer than in the year before transplantation. The patients were also aware of a reduction in dysphagia after transplantation.

Conclusions

These results suggest that cell sheet transplantation may be effective in preventing anastomotic stricture after surgery for congenital esophageal atresia, but the effect was temporary and limited in this case. Although we chose a very severe case for the first human clinical study, it may be possible to obtain a more definitive effect if the transplantation is performed before the disease becomes so severe. Future studies are needed to identify cases in which cell sheet transplantation is most effective and to determine the appropriate timeframes for transplantation.

Trial registration: UMIN, UMIN000034566, registered 19 October 2018, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000039393.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02710-9.

A stable protocol for the fabrication of transplantable human oral mucosal epithelial cell sheets for clinical application

Introduction

Cultured stratified epithelial cell sheets have been clinically utilized as transplantable grafts for the regeneration of epithelial tissues, such as the esophagus, cornea, skin, and intraoral cavity. These cell sheets are expected to gain widespread use as regenerative medicine products and save many patients. For this purpose, establishing and disseminating the stale protocol of fabricating the cell sheet is crucial. The fabrication of cultured stratified epithelial cell sheets consists of many important steps, and since the patients' epithelial cell conditions vary widely and are sometimes unstable, the qualities of the epithelial cell grafts are likewise potentially unstable. Therefore, in this paper, we report the stable protocol for fabrication of the transplantable cell sheet particularly from patient-derived oral mucosal tissues.

Methods

Serum extracted from blood and buccal mucosal tissue were collected in Nagasaki University and transported to Tokyo Women's Medical University. Oral mucosal epithelial cells were collected by minimum trypsin method, and this treatment was studied whether to be a critical procedure. After 14 days cultivation, cultured cells were examined whether to be transplantable as cell sheets.

Results

We successfully transported buccal mucosal tissue and serum without damage and contamination. Oral mucosal epithelial cells were collected with high viability by minimum trypsin method. Finally, we succeeded to stably fabricate oral mucosal epithelial cell sheets in all 10 patients.

Conclusions

We established a stable protocol for the fabrication of human oral mucosal epithelial cell sheets and their transportation in clinical settings in this study. These methodologies could also be basis for transplantation therapy using cultured cell sheets of various types other than oral mucosal epithelial cell and will contribute largely to the future development of regenerative medicine.

Oral keratinocyte-derived exosomes regulate proliferation of fibroblasts and epithelial cells

Extracellular vesicles (EVs), including exosomes, are small membrane-bound particles released by cells. From a therapeutic point of view, EVs can often convey similar biological function as their parent cell. Grafts originating from oral mucosa have frequently been used in regenerative medicine, and we have previously described the use of oral cell sheets to prevent stricture formation of the esophagus. Further, we recently found that exosomes derived from these cell sheets have pro-regenerative effect on skin wound healing. Here, we have isolated exosomes from conditioned media from oral keratinocyte ("OKEx") and dermal fibroblast ("FEx") cultures. The exosomes were probed for classical EV-markers by western blot (CD9, annexin V and Flotillin-1), FEx were positive for all markers while OKEx were positive only for CD9. Tunable resistive pulse sensing indicated a mean size of around 110 nm and transmission electron microscopy showed a spherical morphology, for both groups. After fluorescent labelling, we studied the uptake of exosomes co-cultured with fibroblasts or keratinocytes. Signal from OKEx could be detected after 90 min, and signal could be detected in all groups after 16 h. Finally we studied the exosomes' modulation of cell proliferation. Both groups suppressed proliferation of healthy keratinocyte and fibroblasts, at some doses to similar levels as dexamethasone (a drug commonly used to prevent stricture formation). In contrast, the exosomes also suppressed the proliferation of the carcinoma cell line TR146, while dexamethasone had no effect. In conclusion, we believe that exosome-signaling might be one of the mode-of-actions of cell sheet-therapy for stricture prevention.

Exosomes derived from clinical-grade oral mucosal epithelial cell sheets promote wound healing

The oral mucosa exhibits unique regenerative properties, sometimes referred to as foetal-like wound healing. Researchers from our institute have used sheets of oral mucosa epithelial cells (OMECs) for regenerative medicine applications including cornea replacement and oesophageal epithelial regeneration for stricture prevention. Here, we have isolated exosomes from clinical-grade production of OMEC sheets from healthy human donors (n = 8), aiming to evaluate the clinical potential of the exosomes to stimulate epithelial regeneration and to improve understanding of the mode-of-action of the cells. Exosomes were isolated from conditioned (cExo) and non-conditioned (ncExo) media. Characterization was performed using Western blot for common exosomal-markers: CD9 and flotillin were positive while annexin V, EpCam and contaminating marker GRP94 were negative. Nanoparticle tracking analysis revealed a diameter of ~120 nm and transmission electron microscopy showed a corresponding size and spherical appearance. Human skin fibroblasts exposed to exosomes showed dose-dependent reduction of proliferation and a considerable increase of growth factor gene expression (HGF, VEGFA, FGF2 and CTGF). The results were similar for both groups, but with a trend towards a larger effect from cExo. To study adhesion, fluorescently labelled exosomes were topically applied to pig oesophageal wound-beds ex vivo and subsequently washed. Positive signal could be detected after as little as 1 min of adhesion, but increased adhesion time produced a stronger signal. Next, labelled exosomes were added to full-thickness skin wounds in rats and signal was detected up to 5 days after application. cExo significantly reduced the wound size at days 6 and 17. In conclusion, exosomes from OMEC sheets showed pro-regenerative effects on skin wound healing. This is the first time that the healing capacity of the oral mucosa is studied from an exosome perspective. These findings might lead to a combinational therapy of cell sheets and exosomes for future patients with early oesophageal cancer.

Esophageal tissue engineering: from bench to bedside

For various esophageal diseases, the search for alternative techniques for tissue repair has led to significant developments in basic and translational research in the field of tissue engineering. Applied to the esophagus, this concept is based on the in vitro combination of elements judged necessary for in vivo implantation to promote esophageal tissue remodeling. Different methods are currently being explored to develop substitutes using cells, scaffolds, or a combination of both, according to the severity of lesions to be treated. In this review, we discuss recent advances in (1) cell sheet technology for preventing stricture after extended esophageal mucosectomy and (2) full-thickness circumferential esophageal replacement using tissue-engineered substitutes.

Approaches for stricture prevention after esophageal endoscopic resection

BACKGROUND AND AIMS

Endoscopic resection of extensive esophageal lesions has become more common as endoscopic resection techniques and equipment have developed. However, extensive esophageal endoscopic resections can cause postoperative esophageal strictures, which have a negative impact on the quality of life of patients. We aimed to review current treatments and innovative approaches to prevent esophageal strictures after widespread endoscopic resection of esophageal lesions.

METHODS

We performed a comprehensive literature search from 2000 to 2016 using predetermined search terms to identify relevant articles and summarized their results as a narrative review.

RESULTS

A total of 21 original articles and case series were identified. A circumferential mucosal defect involving more than three fourths of the esophageal luminal circumference was the primary risk factor for developing an esophageal stricture after endoscopic resection. Oral and injectable steroid therapy demonstrated promise in preventing post-endoscopic submucosal dissection esophageal strictures, with both strategies significantly reducing the number of required endoscopic balloon dilations. More data are needed on prophylactic self-expandable metal stents, local botulinum toxin injection, and oral tranilast as a strategy to prevent post-endoscopic submucosal dissection esophageal strictures. Although preliminary studies of tissue-shielding resection sites with polyglycolic acid sheets and fibrin glue and autologous cell sheet transplantation have demonstrated promising results, additional larger validation studies are needed.

CONCLUSIONS

Oral and locally injected/administered steroids are first-line options for the prevention of esophageal strictures, but additional innovative solutions are being developed.

Autologous adipose-derived stem cell sheets enhance the strength of intestinal anastomosis

Objective

Adipose-derived stem cells (ASCs) are capable of multiple differentiation pathways, imparting immunomodulatory effects, and secreting factors that are important for wound healing. These characteristics can be exploited to decrease the incidence of anastomotic leakage.

Methods

In order to delay local wound healing at the anastomotic site, we induced ischemia in a portion of porcine small intestine by ligating vessels. Then, we injected mitomycin C into the serosa of the small intestine above the ligated vessels. Anastomotic sites were created by 2 cm incisions made in the opposite mesenteric area. ASCs were isolated from the porcine subcutaneous fat tissues and expanded under culture conditions. ASCs were trypsinized and seeded on temperature-responsive dishes and cultured to form confluent sheets. Three ASC sheets were transplanted onto the serous membrane after suturing. The extent of anastomotic wound healing was evaluated by bursting pressure, hydroxyproline content, and mRNA expression of collagen-1 alpha1 and collagen-3 alpha1.

Results

We found that transplantation of ASC sheets increased anastomotic site bursting pressure. Additionally, transplantation of ASC sheets increased the hydroxyproline content of the anastomoses. Furthermore, transplantation of ASC sheets increased mRNA expression of collagen-1 alpha1 and collagen-3 alpha1.

Conclusions

Our findings showed that transplantation of autologous ASC sheets enhanced collagen synthesis and anastomotic strength. Further studies are necessary to identify substances that, in combination with ASC sheets, might enhance collagen synthesis and healing in sites of anastomosis.

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Transplantation of adipose-derived stem cell (ASC) sheets after intestinal anastomosis stimulated collagen synthesis and improved anastomotic strength.

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Paracrine effects of the growth factors released by the ASC sheets might contribute to healing at the anastomotic site and stimulate the fibroblast and the collagen synthesis.

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This new approach might be a feasible and promising strategy to prevent anastomotic leakage.

In Vitro and in Vivo Grafting of Xeno Pig Fetal Liver Fragments Using Ultrafiltration Membrane

Transplantation of xeno fetal liver fragments (FLF) could be an alternative or supplementary therapy for acute and chronic liver failure not resolved by routine medical therapies. However, the xenografts themselves are rejected by the host immune system. To overcome these problems, immunoisolate capsules with various cutoff points, from 50,000 (YM30) to 500,000 (ZM500) were tested for their protective effects on FLF graft survival. In an in vitro study, the capsule with the smallest cutoff size (YM30) had an excellent protective effect on the grafts it contained, and showed the lowest GOT values in the culture supernatant and the normal histological structure. In an in vivo study using rats, the same capsule enabled a FLF graft to survive as long as 21 days, even with severe IgG deposition on and within the graft. In another in vivo study, which used beagle dog, however, it did not improve the natural course of survival of the graft, which had totally degenerated by day 7. In conclusion, 1) Immunocapsules, especially those with the smallest cutoff values, impeded the infiltration of the (xeno) humoral attacking factor, but the blocking effect was not complete, as shown by the immunoglobulin (IgG) deposit on the grafts they contained. 2) The FLFs with capsules survived longer than those without capsules—only in rats, not in beagles. This difference may be attributable to the difference of the extent of humoral or nutritional response to the xenografts.

Treatment of chemically induced oral ulcer using adipose-derived mesenchymal stem cell sheet

BACKGROUND

This study investigated the effects of mesenchymal stem cell (MSC) sheet transplantation on healing of chemically induced oral ulceration in a rabbit animal model.

METHODS

Oral mucosal ulcers were induced by topical application of filter paper soaked with 70% acetic acid to the anterior gingiva and buccal mucosa of 12 New Zealand white rabbits. The animals were randomly assigned to two groups: with (treatment group, n = 6) or without (control group, n = 6) cell sheets applied to ulcers. Gross findings were sequentially evaluated, and histologic examination was performed on day 7.

RESULTS

Based on gross inspection, ulceration resolved before day 5 in the treatment group; however, in the control group, healing was incomplete on day 7. In the treatment group, the total area of the ulcer decreased significantly from day 2 to day 5 (P < 0.001) and from day 5 to day 7 (P = 0.020), whereas the area decreased significantly from day 5 to day 7 in the control group (P < 0.001). Histologic and immunofluorescence examination revealed full-thickness mucosa healing and complete basal cell coverage in the treatment group; in contrast, only partial healing was observed on day 7 in the control group.

CONCLUSIONS

Cell sheet technology using MSC can be an alternative treatment for oral ulcerations in that it can decrease healing time without invasive properties.

Transplantation of epidermal cell sheets by endoscopic balloon dilatation to avoid esophageal re-strictures: initial experience in a porcine model

Background and study aims: Epidermal cell sheet (ECS) transplantation immediately after aggressive endoscopic submucosal dissection (ESD) has been shown to be safe and effective in the prevention of esophageal strictures. This study evaluated the feasibility of ECS transplantation after endoscopic balloon dilation (EBD) in a porcine model. Methods: Six pigs underwent circumferential esophageal ESD under general anesthesia. Two weeks later, two pigs underwent EBD and transplantation of an autologous ECS, two underwent EBD alone, and two underwent endoscopic observation only (control). Results: The two pigs in the transplantation group underwent six ECS transplants after EBD with five of the six (83 %) being successful, as shown by engraftment of transplanted ECSs after 7 days. No adverse events were observed. Stricture rates were lower in the two transplanted pigs (55 % and 60 %) than in the control (92.2 % and 87.7 %) and EBD-treated (71.7 % and 78.2 %) pigs. Infiltration of inflammatory cells was significantly lower in the transplanted pigs than in the control and EBD-treated pigs. Conclusion: Preliminary results indicate the stability of the ECS transplantation procedure and the engraftment of transplanted ECS in the tears after EBD. This proof-of-concept study suggests that covering tears with ECSs after EBD may avoid re-strictures.

Transplantation of tissue-engineered cell sheets for stricture prevention after endoscopic submucosal dissection of the oesophagus

BACKGROUND AND OBJECTIVE

Endoscopic mucosal dissection (ESD) is a treatment option for oesophagus tumours localized to the mucosa enabling en bloc removal of large lesions. The resulting larger mucosal defects have resulted in an increase in the occurrence of post-treatment strictures. Transplantation of autologous cell sheets, cultured from oral mucosa, has been shown to prevent post-ESD strictures. The aim of the study was to assess the efficacy and safety of cell sheet transplantation after oesophageal ESD in a Western patient population where reflux-associated pre-malignant and malignant conditions predominate.

METHODS

Patients with Barrett's oesophagus associated high-grade dysplasia or early adenocarcinoma where ESD entailed a resection >3 cm in length and ≥75% of the circumference were eligible for treatment under hospital exemption. Cell sheets were cultured from buccal mucosa according to Good Manufacturing Practice and were endoscopically applied to the post-ESD defect directly after resection. Patients were followed with weekly endoscopy examinations, including confocal laser microscopy, for a total of four weeks.

RESULTS

Five patients were treated. ESD was extensive with resections being circumferential in three patients and 9-10 cm in length in two. The number of transplanted cell sheets ranged from two to six. Three patients developed strictures requiring two to five dilatation sessions.

CONCLUSIONS

Cell sheet transplantation shows to be safe and feasible in a Western population. Results suggest that transplantation has a protective effect on the mucosal defect after ESD, decreasing both the risk for and extent of stricture formation.

Endoscopic cell sheet transplantation device developed by using a 3-dimensional printer and its feasibility evaluation in a porcine model

BACKGROUND

To prevent severe esophageal stenosis after aggressive endoscopic submucosal dissection (ESD), our group previously reported an efficient treatment using cell sheets that had been fabricated from patient cells. However, this transplantation procedure had not been easy for every endoscopist and needed to be improved to derive the full effect of epithelial cell sheets.

OBJECTIVE

To develop an endoscopic device that enables easy and effective cell sheet transplantation and to evaluate its performance and clinical feasibility.

DESIGN

Animal study.

SETTING

Animal experimentation laboratory.

INTERVENTION

Three pigs underwent circumferential esophageal ESD while under general anesthesia. A total of 12 cell sheets were endoscopically transplanted to the ESD site; 6 cell sheets were transplanted by using an endoscopic device that we developed, and 6 cell sheets were transplanted by using the conventional method.

MAIN OUTCOME MEASUREMENTS

Procedure time, transplanted area on the ESD site, transplantation success rate, and monitoring of adverse events or incidents.

RESULTS

The device allowed successful transplantation of all cell sheets with a shorter procedure time than with the conventional method (4.8 ± 0.8 minutes vs 13.3 ± 5.7 minutes, respectively) (P = .005) and onto a larger area (111.3 ± 56.3 mm(2) vs 41.8 ± 4.2 mm(2), respectively) (P = .023) with a higher success rate (100% vs 83%, respectively). No adverse incidents were monitored in each method.

LIMITATIONS

Animal study, small sample.

CONCLUSION

A newly designed endoscopic cell sheet transplantation device would be useful.

Novel isolated cecal pouch model for endoscopic observation in rats

AIM: To create a new rat model for drug administration, cell transplantation, and endoscopic examination for the treatment of intestinal diseases.

METHODS: F344/NJc l-rnu/rnu rats (10-wk-old males, 350-400 g) were used in this study. The rats were anesthetized via 2% isoflurane inhalation. The rat’s cecum was isolated from the intestines, and a pouch was created. The remainder of the intestines was rejoined to create an anastomosis. The “side-to-side” anastomosis (SSA) technique initially involves the creation of a 2-cm longitudinal incision into each intestinal wall. To create an anastomosis along the ileal and colonic walls, both intestines were cut, and a continuous suture procedure was performed that included all layers of both intestines. The serous membrane was sutured along the edge and on the anterior wall of the anastomosis. The “end-to-end” anastomosis (EEA) technique was compared with the SSA technique. In the EEA technique, the frontal surfaces of both cut intestinal lumens were joined together by continuous sutures. Additional sutures were made at the serosa. After the anastomotic intestine was successfully constructed, the two intestinal lumens that were cut at the isolated cecum were managed. In addition, one luminal side of the pouch remained open to create an artificial anus on the dorsum as a passage for the residual substances in the pouch. Finally, small animal endoscopy was used to observe the inside of the pouch.

RESULTS: In this animal model, mucus and feces are excreted through the reconstructed passage. Accordingly, the cecal pouch mucosa was not obstructed or contaminated by feces, thus facilitating observations of the luminal surface of the intestine. The endoscopic observation of the cecal pouch provided clear visualization given the absence of feces. The membrane surface of the cecum was clearly observed. Two methods of creating an anastomotic intestine, the “SSA” and “EEA” techniques, were compared with regard to animal survival rate, complication rate, and operation time. The SSA technique resulted in a significantly increased survival rate and a lower incidence of complications in rat models compared with the EEA technique. The complications of stenosis and leakage resulted in death in the EEA technique. Thus, the EEA technique exhibited a lower survival rate compared with the SSA technique. However, the SSA technique required a significantly longer operation time compared with the EEA technique.

CONCLUSION: Our new rat model is potentially useful for the development of a novel treatment for intestinal diseases.

How to prevent contamination with Candida albicans during the fabrication of transplantable oral mucosal epithelial cell sheets

We have utilized patients' own oral mucosa as a cell source for the fabrication of transplantable epithelial cell sheets to treat limbal stem cell deficiency and mucosal defects after endoscopic submucosal dissection of esophageal cancer. Because there are abundant microbiotas in the human oral cavity, the oral mucosa was sterilized and 40 μg/mL gentamicin and 0.27 μg/mL amphotericin B were added to the culture medium in our protocol. Although an oral surgeon carefully checked each patient's oral cavity and although candidiasis was not observed before taking the biopsy, contamination with Candida albicans (C. albicans) was detected in the conditioned medium during cell sheet fabrication. After adding 1 μg/mL amphotericin B to the transportation medium during transport from Nagasaki University Hospital to Tokyo Women's Medical University, which are 1200 km apart, no proliferation of C. albicans was observed. These results indicated that the supplementation of transportation medium with antimycotics would be useful for preventing contamination with C. albicans derived from the oral mucosa without hampering cell proliferation.

•

Normal human oral mucosal epithelial cells were cultured in a clinical setting.

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Contamination with Candida albicans was detected in the culture.

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The culture medium included 0.27 μg/mL amphotericin B.

•

Contamination was prevented by 1 μg/mL amphotericin B in the medium for transportation of the oral tissue.

Application of regenerative medical technology using tissue-engineered cell sheets for endoscopic submucosal dissection of esophageal neoplasms

We have developed a technique for endoscopic transplantation of cultured autologous oral mucosal epithelial cell sheets to an esophageal ulcer following endoscopic submucosal dissection (ESD). The epithelial cell sheets successfully prevented esophageal stricture after ESD. Key technology is that epithelial cell sheets cultured from oral mucosal tissue and attached proteins can be harvested using cell sheet technology and can be transplanted to a wound site without the use of adhesive material. This regenerative procedure can promote the epithelialization of ulceration safely and effectively. In the near future, the development of advanced endoscopic treatment of regenerative medicine shows promise.

Prevention of esophageal strictures after endoscopic submucosal dissection

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have recently been accepted as less invasive methods for treating patients with early esophageal cancers such as squamous cell carcinoma and dysplasia of Barrett’s esophagus. However, the large defects in the esophageal mucosa often cause severe esophageal strictures, which dramatically reduce the patient’s quality of life. Although preventive endoscopic balloon dilatation can reduce dysphagia and the frequency of dilatation, other approaches are necessary to prevent esophageal strictures after ESD. This review describes several strategies for preventing esophageal strictures after ESD, with a particular focus on anti-inflammatory and tissue engineering approaches. The local injection of triamcinolone acetonide and other systemic steroid therapies are frequently used to prevent esophageal strictures after ESD. Tissue engineering approaches for preventing esophageal strictures have recently been applied in basic research studies. Scaffolds with temporary stents have been applied in five cases, and this technique has been shown to be safe and is anticipated to prevent esophageal strictures. Fabricated autologous oral mucosal epithelial cell sheets to cover the defective mucosa similarly to how commercially available skin products fabricated from epidermal cells are used for skin defects or in cases of intractable ulcers. Fabricated autologous oral-mucosal-epithelial cell sheets have already been shown to be safe.

Cell sheets engineering for esophageal regenerative medicine

Recently, cell-based therapies, regenerative medicine, and tissue engineering have been progressing rapidly. We have developed a novel strategy for regenerative medicine to recover tissue functions using temperature-responsive cell culture surfaces. To overcome of conventional methods such as the usage of single-cell suspension injection, we have applied transplantable cell sheets fabricated with temperature-responsive culture surfaces for cell delivery. In the field of gastroenterology, transplantable cell sheets from autologous oral mucosal epithelial cells can prevent esophageal stricture following extensive endoscopic mucosal resection.

Cell sheet technology for regeneration of esophageal mucosa

The progress of tissue-engineering technology has realized development of new therapies to treat various disorders by using cultured cells. Cell- and tissue-based therapies have been successfully applied to human patients, and several tissue-engineered products have been approved by the regulatory agencies and are commercially available. In the review article, we describe our experience of development and clinical application of cell sheet-based regenerative medicine. Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been shown to be useful for removal of gastrointestinal neoplasms with less invasiveness compared with open surgery, especially in esophageal surgery. However, postoperative inflammation and stenosis are major complications observed after intensive mucosal resection. Therefore, we have developed novel regenerative medicine to prevent such complications and promote wound healing of esophageal mucosa after EMR or ESD. Transplantable oral mucosal epithelial cell sheets were fabricated from patients’ own oral mucosa. Immediately after EMR or ESD, fabricated autologous cell sheets were endoscopically transplanted to the ulcer sites. We performed a preclinical study with a canine model. In human clinical settings, cell culture and cell sheet fabrication were performed in clean rooms according to good manufacturing practice guidelines, and pharmaceutical drugs were used as supplements to culture medium in place of research regents used in animal study. We believe that cell-based regenerative medicine would be useful to improve quality of life of patients after EMR or ESD.

[Regenerative medicine using cell-sheet engineering]

We have developed a novel strategy for regenerative medicine to recover tissue functions using temperature-responsive cell culture surfaces. To overcome the disadvantages of conventional methods such as the usage of single-cell suspension injections and biodegradable polymer scaffolds, we use transplantable cell sheets fabricated with temperature-responsive culture surfaces for cell delivery. Here, we summarize our progress in promoting regenerative medicine using cell-sheet engineering with respect to research and regulatory systems and describe recent challenges in the standardization of cell-sheet engineering.

AURKA is one of the downstream targets of MAPK1/ERK2 in pancreatic cancer

DUSP6/MKP-3, a specific inhibitor of MAPK1/ERK2, frequently loses its expression in primary pancreatic cancer tissues. This evidence suggests that constitutive activation of MAPK1 synergistically induced by frequent mutation of KRAS2 and the loss of function of DUSP6 plays key roles in pancreatic carcinogenesis and progression. By profiling of gene expressions associated with downregulation of MAPK1 induced by exogenous overexpression of DUSP6 in pancreatic cancer cells, we found that AURKA/STK15, the gene encoding Aurora-A kinase, which plays key roles in cellular mitosis, was among the downregulated genes along with its related genes, which included AURKB, TPX2 and CENPA. An association of expression and promoter activity of AURKA with MAPK activity was verified. Knockdown of ETS2 resulted in a reduction of AURKA expression. These results indicate that AURKA is a direct target of the MAPK pathway and that its overexpression in pancreatic cancer is induced by hyperactivation of the pathway, at least via ETS2.

Immunohistochemical classification of the localization of laminin in the thickened bronchial epithelial basement membrane of deceased bronchial asthma patients

To ascertain histological changes in the basal lamina of the bronchial epithelial basement membrane in patients with severe bronchial asthma, an immunohistochemical study was conducted in 43 patients who died of bronchial asthma. Antibodies against laminin, a component of the lamina lucida, were utilized. The results revealed various patterns for immunoreactivity to laminin in the thickened basement membrane layer. We were able to classify these reactivities into four patterns. In Pattern A, laminin reactions branched vertically in relation to the thickened basement membrane layer. In Pattern B, laminin reactions formed lines along the lower margin of the thickened basement membrane layer. In Pattern C, laminin reactions formed lines along the upper margin of the thickened basement membrane layer. Finally, in Pattern D, no laminin reactions were observed. In addition, relationships between immunohistological characteristics of laminin and findings such as epithelial cell shedding, basal cell proliferation and basement membrane layer thickening were investigated. In many Pattern A patients, epithelial cell shedding was observed, but goblet cell hyperplasia and basal cell proliferation were barely detectable. Conversely, in numerous Pattern D patients, epithelial cell shedding was barely seen, but goblet cell hyperplasia and basal cell proliferation were marked. Hence, Patterns A and D were on opposite ends of the spectrum of morphological characteristics associated with severe bronchial asthma. In Patterns B and C, laminin reactions formed lines along the lower and upper margin of the thickened basement membrane layer, respectively. However, no marked differences existed in epithelial cell shedding and basement membrane layer thickening. The present study is thus the first to clarify that laminin reactions in the thickened basement membrane layer vary, and this feature is unique to the bronchi of patients with severe bronchial asthma.

Utility and limitations of intraductal ultrasonography in distinguishing longitudinal cancer extension along the bile duct from inflammatory wall thickening

BACKGROUND

We wanted to distinguish wall thickening caused by cancer extension from that caused by inflammation after placing a biliary catheter on intraductal ultrasonography (IDUS).

METHODS

We studied 51 patients with biliary tract malignancies who had undergone placement of biliary drainage catheters before IDUS. IDUS was performed from a transhepatic (n = 34) or transpapillary (n = 17) route with a thin-caliber ultrasonic probe (2.0 mm in diameter, 20-MHz frequency). At the hepatic side of the tumor, the thickness, asymmetry, outer margin, inner margin, and internal echoes of the bile duct wall were reviewed prospectively and correlated with the histologic findings of the surgically resected specimens in all cases.

RESULTS

When IDUS showed wall thickening in a semicircular fashion, notched outer margin, rigid inner margin, papillary inner margin, and heterogeneous internal echoes, each finding had a positive predictive value for diagnosing cancer extension (100%, 100%, 83%, 100%, and 90%, respectively). When these factors were used as the diagnostic criteria of cancer extension, IDUS accurately demonstrated suitable surgical margins in 76% of all patients and 71% of patients with bile duct carcinoma.

CONCLUSION

Wall thickening in a semicircular fashion, notched outer margin, rigid or papillary inner margin, and heterogeneous internal echoes are specific for cancer extension. However, surgical margins can be inaccurately assessed in some patients.

Living-related partial liver transplantation for decompensated hepatitis B without reactivation of hepatitis B in the following 30 months

We report a case of living-related partial liver transplantation for decompensated hepatitis B without reactivation of hepatitis B in the following 30 months, and we analyze the factors that indicate a favorable prognosis for transplantation. The 42-year-old female patient received continuously administered lamivudine before transplantation, and hepatitis B virus immunoglobulin (HBIG) from the anhepatic phase to the present. Currently, she shows a normal aminotransferase level and is negative for hepatitis B surface antigen and hepatitis B virus (HBV) DNA by polymerase chain reaction amplification. Sequence analysis was performed. The entire precore/core region and part of the polymerase region of HBV were sequenced by a direct sequencing method after polymerase chain reaction. No specific mutation was found in these regions. These observations show that the key factors in the long-term successful treatment of this patient appear to be the combination therapy of lamivudine and HBIG that the patient received from around the time of the transplantation. Furthermore, the lack of specific mutations, including lamivudine resistant-mutations, is likely to represent an additional factor in the effectiveness of this treatment.

Transpapillary intraductal US prior to biliary drainage in the assessment of longitudinal spread of extrahepatic bile duct carcinoma

BACKGROUND

The utility of intraductal US via the transpapillary route prior to biliary drainage in the assessment of longitudinal extension of extrahepatic bile duct carcinoma was investigated.

METHODS

In 19 patients with extrahepatic bile duct carcinoma who underwent surgical resection, an ultrasonic probe (diameter, 2.0 mm; frequency, 20 MHz) was inserted into the bile duct via the transpapillary route prior to biliary drainage. Longitudinal cancer extension along the bile duct was prospectively determined and compared with the histologic findings in the resected specimens.

RESULTS

Results on the hepatic side were as follows: Intraductal US demonstrated more extensive longitudinal cancer spread than cholangiography in 9 of 19 patients with one instance of overdiagnosis. The accuracy of intraductal US in assessing the extent of spread (84%) was superior to that of cholangiography (47%) (p < 0.05). Results on the duodenal side were as follows: In patients with suprapancreatic bile duct cancer (n = 14), intraductal US demonstrated more extensive longitudinal cancer spread than cholangiography in 8 of 14 patients. The accuracy of intraductal US in assessing the extent of the spread (86%) was superior to that of cholangiography (43%) (p < 0.05).

CONCLUSIONS

Transpapillary intraductal US prior to biliary drainage is useful in demonstrating longitudinal extension of bile duct cancer. However, the surgical margins were inaccurate in some patients.

Identification and characterization of a novel gene that is upregulated in leukaemia cells by nitric oxide

Nitric oxide (NO) inhibits growth and induces differentiation in acute myeloid leukaemia (AML) cells. To identify genes associated with these processes, we studied the effect of NO on AML gene expression using the technique of Representational Difference Analysis. Exposure of HL-60 cells to the NO donor DETA-NO for 24 h induced the expression of a novel gene that was named rno (regulated by nitric oxide). Treatment of HL-60 cells with dimethyl sulphoxide induced expression of rno, but treatment with Vitamin D3 or all-trans retinoic acid did not. Upregulation of rno by NO was cGMP independent. Northern blot analysis indicated that constitutive expression of the novel gene was limited to leucocytes. Three isoforms of rno were identified. An rno cDNA clone was obtained by screening a human leucocyte library. The nucleotide sequence of the open reading frame shared significant homology with that of the human ribonuclease/angiogenin inhibitor (RI). The predicted amino acid sequence indicated that, like RI, rno is leucine and cysteine rich and is comprised of a series of repetitive elements (leucine-rich repeats) that may mediate macromolecular interactions. Enhancement of expression of rno may be a component of the process by which differentiation and growth inhibition of leukaemia cells is induced by NO.

Xenotransplantation of the liver

Xenotransplantation of the liver, in its broadest conception, might involve the transplantation of an intact organ or xenogeneic hepatocytes, or the use of an intact xenogeneic liver or cells as an ex vivo "device." The indications for xenotransplantation include not only hepatic failure but also, potentially, the treatment of metabolic diseases. The hurdles to xenotransplantation include immune, physiologic, and infectious complications. New information and progress in experimental systems are bringing xenotransplantation closer to clinical application.

Biliopancreatic fistula associated with intraductal papillary-mucinous pancreatic cancer: institutional experience and review of the literature

Intraductal papillary-mucinous tumour is clinicopathologically characterized by papillary growth and mucin production within the pancreatic duct system. The category includes a wide range of dysplasia, ranging from adenoma to carcinoma, the latter designated as intraductal papillary-mucinous cancer. In general, the tumor renders a favorable prognosis after complete resection. However, intraductal papillary-mucinous tumor with overt invasion outside the gland has been reported to have a poor prognosis, as is the case with the usual type of duct cell cancer of the pancreas. We experienced two cases of intraductal papillary-mucinous cancer with obstructive jaundice due to impaction of thick mucus protruding from the pancreas via a "spontaneous" biliopancreatic fistula. Preoperative examinations of both patients showed a large intraductal papillary-mucinous tumor in the head of the pancreas with fistula formation between the intrapancreatic portion of the common bile duct and the main pancreatic duct. Histopathological investigation of the two resected specimens suggested that the fistula may not have developed from invasion by papillary or tubular adenocarcinoma, but from compression and destruction of the intercalating tissues by abundant mucinous secretion. The first patient died of peritoneal carcinomatosis with clinicopathologic features of pseudomyxoma peritonei 6 years after surgery. The second patient is alive and has been well for 2 years postoperatively. Review of the world literature showed that half of the patients with intraductal papillary-mucinous cancer plus biliopancreatic fistula had no stromal invasion around the fistula, indicating that the fistula might have been caused by mechanical pressure. However, the other half of the cases did have stromal invasion around the fistula. Two-thirds of these cases, including our own patients, had foci of mucinous carcinoma in the stroma around the fistulization, implying that mucinous lakes in the stroma may have served as part of the "waterway" from the pancreatic duct to the bile duct, assisted by increased pressure by mucus production. Since intraductal papillary-mucinous cancer with biliopancreatic fistula has a comparatively favorable prognosis, surgical resection should be considered.

Inhibition of Epstein-Barr virus (EBV)-specific CD8+ cytotoxic T lymphocyte (CTL) activity by soluble HLA class I in vitro

In the present study, the effects of soluble HLA (sHLA) class I molecules against EBV-specific CTL were examined. Two different sources of sHLA class I, either bioengineered spliced form of HLA-B7 (sB7) or natural production from EBV-transformed B cells (natural sHLA), were added during the induction of CTL or incubated with MHC-restricted CD8+ CTL, which were selected by immunobeads just before testing for their cytotoxic activity. Both sB7 and natural sHLA class I blocked the generation of CD8+ CTL and also inhibited the cytotoxic activity of established CTL in a dose-dependent manner. In both ways, natural sHLA class I was effective in 10-fold lower concentrations compared with sB7. The inhibitory effect did not require a sharing of the HLA allotypes between sHLA and the CTL. CTL, after being treated with sHLA, underwent apoptosis, which was considered here as the main mechanism.

Prediction of the histologic type of bile duct cancer by using intraductal ultrasonography

BACKGROUND

Patients with papillary adenocarcinoma survive longer than do patients with other histologic types of bile duct tumors. We evaluated the usefulness of intraductal ultrasonography (IDUS) for predicting the histology.

METHODS

Preoperative tumor assessment was performed by using IDUS through a percutaneous tract or the transpapillary route in 37 patients with extrahepatic bile duct cancer. In 30 of 37 patients, imaging results were compared prospectively with histologic findings in resected specimens. Probes 2.0 mm in diameter and 20 MHz in frequency were mainly used. When IDUS showed a "narrow-based polypoid pattern" or a "papillary surface pattern," the patients were judged as having papillary adenocarcinoma.

RESULTS

The accuracy, sensitivity, and specificity of IDUS in predicting papillary adenocarcinoma were 90%, 89%, and 90%, respectively. When intraductal ultrasonography showed a papillary surface pattern or a narrow-based polypoid pattern, lymph node metastases and perineural invasion were rarely seen when compared with other patients with bile duct cancer (p < 0.05).

CONCLUSION

IDUS is useful for assessing the histologic type of bile duct cancer.

Rapid death following papillary serous carcinoma of the endometrium without myometrial invasion

A 72-year-old woman was diagnosed with a stage I endometrial carcinoma, and total hysterectomy, bilateral salpingo-oophorectomy, and systematic pelvic and paraaortic lymphadenectomy were performed. Postoperative pathological examination determined that the tumor was confined to the endometrium, with no myometrial invasion or lymph-vascular involvement; histological examination revealed a papillary serous carcinoma of the endometrium. Peritoneal washing cytology during surgery revealed an adenocarcinoma. Despite postoperative adjuvant chemotherapy, early recurrence resulted in death 13 months after surgery. In the absence of myometrial invasion and lymph-vascular involvement, the data suggest that peritoneal washing cytology may serve as a prognostic factor in papillary serous carcinoma of the endometrium.

A novel method of endoscopic mucosal resection using sodium hyaluronate

BACKGROUND

Saline-assisted endoscopic mucosal resection is an established therapeutic method. However, it is sometimes difficult to maintain a desired level of tissue elevation after injection of saline. Therefore we decided to use a mucinous substance such as sodium hyaluronate instead of saline.

METHODS

Two resected porcine stomachs and five dogs were used for the study. The elevations, made by submucosal injections of sodium hyaluronate, were compared with those produced with normal saline. Sodium hyaluronate-assisted mucosal resections were compared with the saline-assisted resections.

RESULTS

Mucosal elevations created by submucosal injections of sodium hyaluronate remained for a longer time with a clearer margin compared to those made by saline injection. Endoscopic mucosal resections were performed safely with the assistance of sodium hyaluronate.

CONCLUSIONS

Use of sodium hyaluronate instead of saline for endoscopic mucosal resection could make the procedure easier and more reliable.

[Systemic lupus erythematosus presenting as fulminant thrombotic thrombocytopenic purpura]

A 20-year-old woman visited a nearby hospital because of sudden, severe, and unusual genital bleeding. She also exhibited severe anemia and thrombocytopenia. In transit to our hospital, the patient suddenly suffered cardiac arrest and died soon thereafter despite immediate blood transfusion and therapeutic intubation. Thrombotic thrombocytopenic purpura (TTP) was initially diagnosed at autopsy due to the observation of numerous fragmented erythrocytes in peripheral blood, evidence of hemolysis, and thrombotic microangiopathy in multiple organs. In addition, histopathologic and serologic findings disclosed an association with systemic lupus erythematosus (SLE). Test for anticardiolipin antibody was positive, and hemophagocytic findings were detected in lymph node specimens. Reports of TTP in association with SLE have been increasing in recent years. However, the mechanisms correlating these two illnesses have not been identified. We speculated that the rapid clinical course in this case was attributable to TTP that had been provoked by endothelial microangiopathy due to SLE, and moreover, the fact that the patient's general condition had been seriously complicated by excessive menstrual bleeding.

Paroxysmal nocturnal hemoglobinuria: analysis of the effects of mutant PIG-A on gene expression

Compelling evidence indicates that mutations in PIG-A are necessary for the development of paroxysmal nocturnal hemaglobinuria (PNH), however, it is unclear why mutant PIG-A stem cells have a selective advantage. Further, multiple, discrete PIG-A mutations have been detected in the peripheral blood and bone marrow of patients with PNH, but the contribution of the different mutant clones to hematopoiesis is variable. This observation implies that factors in addition to mutant PIG-A influence the proliferative properties of the abnormal cells. To investigate the etiology of the selective advantage and the clonal dominance in PNH, gene expression in cells with mutant PIG-A was analyzed. Representational difference analysis was used to compare the pattern of cDNA expression between a human lymphoblastoid cell line with mutant PIG-A and its wild-type counterpart. These experiments demonstrated that the pattern of gene expression was different between the two cells lines in that the PIG-A mutant cells failed to express antiquitin mRNA. Transfection of the mutant cells with normal PIG-A restored expression of glycosyl phosphatidylinositol anchored proteins but not antiquitin. These experiments demonstrate that differences in the pattern of gene expression can occur independent of the PIG-A mutation. Depending upon the functional properties of the involved genes, these differences could influence the proliferative properties of PIG-A mutant cells and contribute to the selective advantage and clonal dominance that characterize PNH.

Limitation of cholangiography in assessing longitudinal spread of extrahepatic bile duct carcinoma to the hepatic side

BACKGROUND

Preoperative assessment of longitudinal spread of bile duct carcinoma (BDC) to the hepatic side remains a difficult problem for diagnostic imaging.

METHODS

We studied the accuracy of cholangiography in assessing BDC. In 54 patients with extrahepatic bile duct cancer, cholangiographic findings were compared retrospectively with the histological findings of the resected specimens.

RESULTS

Histological examination of specimens indicated longitudinal spread of the tumour to the hepatic side in 22 of 54 patients. The accuracy of cholangiography in assessing the extent of the longitudinal spread was only 34/54 (63%). When the cholangiographic images showed a main tumour with a collapsed edge, there was a significantly higher frequency of longitudinal spread compared with tumours with sharp edges (P< 0.05). In contrast, the accuracy of mapping biopsy under percutaneous transhepatic cholangioscopy (n=24) was 83%.

CONCLUSIONS

Cholangiography cannot accurately assess the extent of the longitudinal spread of bile duct cancer. When cholangiographic images show a tumour with a collapsed edge, preoperative or intraoperative histological examination is essential to determine a suitable surgical line.

Beneficial effects of immunoisolated fetal and neonatal pig liver fragments on acute liver failure in a large animal

Xenogeneic cell (fragment) transplantation may be used as an interim therapy until the organ allotransplanation. Immunologic rejection, however, constitutes the major hurdle. To overcome this problem, "xeno" fetal and neonatal liver fragments (FLF, NLF) were encapsulated into separate micropore devices that protect them from immunological attack by the recipient. The FLF or NLF were then transplanted into beagles with hepatic failure to observe their biological effects. In Experiment 1 (n = 5) beagles were injected IV with D-galactosamine (D-gal, 1.0 g/kg) on day 0 and then received FLF grafts (0, 0.3, 0.8, 1.0, 2.0 g/kg). In Experiment 2 (n = 6) beagles received NLF grafts (1.8 g/kg) and on the following day were injected with D-gal (1.0 g/kg). In Experiment 1 only the high dose of xeno-FLF (2.0 g/kg) decreased the elevated ALT (GPT) and T. Bil. levels. Histologic examination showed that some of the hepatocytes of the host liver survived only in the high-dose graft. In Experiment 2, at 36 and 48 h after D-gal injection, the transplanted group had a significantly lower AST (GOT) level than the control. The grafted NLF survived for 14 days, according to histologic examinations. Thus, encapsulated FLF and NLF xenotransplantation can prevent liver dysfunction in a large animal hepatic failure model.

The impact of HLA-A matching in corneal transplantation

Previously, we have reported the results of our retrospective study on the effect of HLA class II allele matching on the outcome of corneal transplant. Here, we demonstrate our findings of the study for HLA class I allele matching in the same study subjects. Eighty transplant recipients were typed for HLA-A, and 79 transplant recipients were typed for HLA-B alleles, by PCR-SSOP. The association between HLA class I allele matching and 1-year rejection-free graft survival was evaluated. When a total of 79 transplant recipients were subdivided into groups with matching (one to four alleles matched) and without matching (no allele matched) for HLA class I (HLA-A and -B), a significantly higher rate of 1-year rejection-free graft survival was detected in transplant recipients with matching, compared with those without matching (p=0.0258). We have found that matching for at least one HLA class I allele was more beneficial especially in high-risk transplant recipients (p=0.0076). Also, an analysis of matching for each locus separately, detected that, HLA-A matching was significantly associated with a higher rate of 1-year rejection-free graft survival. Transplant recipients with HLA-A matching (one or two-alleles matched) had significantly higher rejection-free graft survival compared with those without matching (no allele matched), when high- and low-risk groups were analyzed together (p=0.0099). Furthermore, matching for HLA-A allele was significantly beneficial compared with no matching in high-risk transplant recipients (p=0.0154). Nevertheless, no significant effect of HLA-B matching was detected. We conclude that HLA class I, especially HLA-A matching has a beneficial effect for corneal transplant outcome.

Delayed hyperacute xenograft rejection in porcine to canine fetal liver transplantation

Fetal tissues are generally considered to express weaker antigenic cell-surface molecules than adult tissues. We have reported that transplantation of porcine fetal liver tissue (fragments) is useful for acute and chronic hepatic failure in rats. We further investigated, in the present study, whether transplantation of a porcine fetal liver has the advantage of delayed hyperacute xenograft rejection (HAR) in comparison with that of an adult liver. Porcine fetal liver heterotopically transplanted into dogs was compared. Haematoxylin-eosin (HE) and immunohistochemical studies using IgM, C3, IgG antibodies were performed in serial biopsies of the liver grafts. Lectin binding to target antigen epitopes on pig and dog tissues was studied by flow cytometry. Carbohydrate expression on the liver was also studied by immunohistochemistry. The macroscopic and HE section findings indicate that HAR started 15 min postgraft in fetal and adult liver grafts. Thereafter, vascular changes and parenchymal damage progressed more rapidly in the adult grafts. The final HAR time in adult liver transplantation was determined to be 60 min, while it was determined to be 180 min in fetal liver transplantation. IgM, C3 and IgG were deposited more strongly in the adult grafts than in the fetal grafts up until 60 min after xenografting. Phaseolus vulgaris erythroagglutinin lectin competitively blocked dog sera binding to porcine PBLs. The fetal liver expressed oligosaccharide at a significantly lower level than the adult liver. We conclude that porcine fetal liver xenografts had a significantly delayed HAR.

Study of the relation between fluid distribution change in tissue and impedance change during hemodialysis by frequency characteristics of the flowing blood

Erythrocyte orientation and deformation cause differences in impedance between flowing and resting blood. Through theoretical calculation and experimental measurements, we studied the effects of these factors on blood impedance. The size and shape of the erythrocyte and the conductivity of the interior medium of the erythrocyte change when the osmotic pressure of plasma is changed. From experimental results, we obtained the following: when the size of the erythrocyte becomes larger than the normal size due to the osmotic pressure change, the beta dispersion frequency decreases and the intra- and extracellular fluid resistance increase. These experimental results corroborate that the change of tissue impedance like muscle impedance during hemodialysis is caused by the change of the fluid distribution and the change of ionic concentration of the electrolyte in tissues during hemodialysis. Also, we could estimate the relative change value of the intra- and extracellular fluid volume by the impedance method, if there were no ionic concentration change in the electrolyte. It would be very difficult to estimate the absolute change value of them because a shadow effect due to the cells depends greatly upon the shape and size of the cells and the cell concentration.

Preoperative assessment of congenital bile duct dilatation using intraductal US

BACKGROUND

Although congenital bile duct dilatation is frequently associated with biliary tract cancer, conventional cholangiography often does not demonstrate small ductal tumors. This is the first prospective study of the value of intraductal ultrasonography (US) in the examination of the extrahepatic bile ducts in patients with congenital bile duct dilatation.

METHODS

Intraductal US via a transpapillary route was used in consecutive patients with congenital bile duct dilatation. A 2.0 mm diameter, 20 MHz frequency catheter probe was used. The images were correlated with the results of histologic examination of the resection specimens.

RESULTS

Intraductal US was performed successfully via the transpapillary route in 8 of 10 patients. In the other 2 patients, the percutaneous transhepatic route was used. In the 6 patients with cylindrical dilatation, intraductal US demonstrated the entire extrahepatic bile duct. In 1 patient, it showed a bile duct cancer not demonstrated by cholangiography. In 2 of the 4 patients with cystic dilatation, intraductal US did not demonstrate the entire extrahepatic bile duct because of the low penetration depth of the probe. Percutaneous transhepatic cholangioscopy was required in these patients.

CONCLUSIONS

Intraductal US is useful for demonstrating cancers in the extrahepatic bile ducts in patients with congenital cylindrical ductal dilatation.

A G to A transition at the last nucleotide of exon 6 of the gamma c gene (868G-->A) may result in either a splice or missense mutation in patients with X-linked severe combined immunodeficiency

We report here that a defect of the interleukin common gamma subunit (gamma c) in X-linked severe combined immunodeficiency (XSCID) previously known as a missense mutation resulted instead in exon skipping in a Japanese XSCID patient. The phenotype of the patient was consistent with that of typical XSCID, and his Epstein-Barr virus-transformed B cells accordingly entirely lacked surface expression of gamma c . On analysis by the reverse transcription-polymerase chain reaction (RT-PCR), a single but small gamma c mRNA species was detected. Exon 6, which encodes the transmembrane domain of gamma c, was skipped in the mRNA. A G to A mutation was found at the last nucleotide of exon 6 of the gamma c gene (868G-->A). The predicted consequence of the exon skipping is a frameshift resulting in a premature stop codon, and the mutated gamma c presumably loses association with the cell membrane. In XSCID, this mutation (868G-->A) is known as a missense mutation that results in R285Q [corrected]. Previously reported patients with the same mutation apparently had no aberrant or alternative splicing but did have the R285Q [corrected] exchange. Similar mutations at the last nucleotide of an outskipped exon have been reported. However, such mutations do not always cause exon skipping. Analyses of RNA structural changes induced by the mutations supported the variability of consequences of the mutations. Taken together, our findings suggest that the 868G-->A mutation of the gamma c gene may affect gamma c transcripts differently, i.e., generating missense or exon skipping, in XSCID patients with the same mutation. Patient-specific variation in splicing thus appears to occur.

The effects of various extracellular matrices on renal cell attachment to polymer surfaces during the development of bioartificial renal tubules

Extracellular matrices (ECM) are utilized for obtaining better cell attachment to polymer surfaces in cell cultures. To establish beneficial bioartificial renal tubules, tubular epithelial cells and ECM were investigated in this study. MDCK cells and KU-2 cells were seeded onto 96 well plates which had been precoated with collagen types I and IV, laminin, and fibronectin. The culture media were removed and replaced with new ones at 15, 30, 60, 90, 120, and 150 min and 24 h after start time to evaluate the incubation time effects. The degrees of cell attachment onto ECM were measured by MTT assay. In the MDCK cell culture, better cell attachment was observed between 60 min and 24 h after incubation start time with the use of laminin at a concentration of 5 microg/ml, 60 min and more after incubation start time with the use of fibronectin at the concentrations of 1 and 4 microg/ml, or 30 min and more after incubation start time with the use of fibronectin at the concentrations of 16 and 32 microg/ml. On the other hand, in the KU-2 cell culture, better cell attachment was observed between 15 and 60 min after the incubation start time or 24 h after the incubation start time with the use of laminin at a concentration of 40 microg/ml. These data suggest that various cells possibly each have a most suitable ECM kind, best concentration, and best incubation time.