Multiplex SARS-CoV-2 Genotyping Reverse Transcriptase PCR for Population-Level Variant Screening and Epidemiologic Surveillance

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with concerning phenotypic mutations is of public health interest. Genomic surveillance is an important tool for a pandemic response, but many laboratories do not have the resources to support population-level sequencing. We hypothesized that a nucleic acid amplification test (NAAT) to genotype mutations in the viral spike protein could facilitate high-throughput variant surveillance. We designed and analytically validated a one-step multiplex allele-specific reverse transcriptase PCR (RT-qPCR) to detect three nonsynonymous spike protein mutations (L452R, E484K, N501Y). Assay specificity was validated with next-generation whole-genome sequencing. We then screened a large cohort of SARS-CoV-2-positive specimens from our San Francisco Bay Area population. Between 1 December 2020 and 1 March 2021, we screened 4,049 unique infections by genotyping RT-qPCR, with an assay failure rate of 2.8%. We detected 1,567 L452R mutations (38.7%), 34 N501Y mutations (0.84%), 22 E484K mutations (0.54%), and 3 (0.07%) E484K plus N501Y mutations. The assay had perfect (100%) concordance with whole-genome sequencing of a validation subset of 229 specimens and detected B.1.1.7, B.1.351, B.1.427, B.1.429, B.1.526, and P.2 variants, among others. The assay revealed the rapid emergence of the L452R variant in our population, with a prevalence of 24.8% in December 2020 that increased to 62.5% in March 2021. We developed and clinically implemented a genotyping RT-qPCR to conduct high-throughput SARS-CoV-2 variant screening. This approach can be adapted for emerging mutations and immediately implemented in laboratories already performing NAAT worldwide using existing equipment, personnel, and extracted nucleic acid.

Multiplex SARS-CoV-2 Genotyping Reverse Transcriptase PCR for Population-Level Variant Screening and Epidemiologic Surveillance

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with concerning phenotypic mutations is of public health interest. Genomic surveillance is an important tool for a pandemic response, but many laboratories do not have the resources to support population-level sequencing. We hypothesized that a nucleic acid amplification test (NAAT) to genotype mutations in the viral spike protein could facilitate high-throughput variant surveillance. We designed and analytically validated a one-step multiplex allele-specific reverse transcriptase PCR (RT-qPCR) to detect three nonsynonymous spike protein mutations (L452R, E484K, N501Y). Assay specificity was validated with next-generation whole-genome sequencing. We then screened a large cohort of SARS-CoV-2-positive specimens from our San Francisco Bay Area population. Between 1 December 2020 and 1 March 2021, we screened 4,049 unique infections by genotyping RT-qPCR, with an assay failure rate of 2.8%. We detected 1,567 L452R mutations (38.7%), 34 N501Y mutations (0.84%), 22 E484K mutations (0.54%), and 3 (0.07%) E484K plus N501Y mutations. The assay had perfect (100%) concordance with whole-genome sequencing of a validation subset of 229 specimens and detected B.1.1.7, B.1.351, B.1.427, B.1.429, B.1.526, and P.2 variants, among others. The assay revealed the rapid emergence of the L452R variant in our population, with a prevalence of 24.8% in December 2020 that increased to 62.5% in March 2021. We developed and clinically implemented a genotyping RT-qPCR to conduct high-throughput SARS-CoV-2 variant screening. This approach can be adapted for emerging mutations and immediately implemented in laboratories already performing NAAT worldwide using existing equipment, personnel, and extracted nucleic acid.

Significance of research in a surgeon-scientist's career - A view from Japan

Reflections of academic pediatric surgery in Japan are shared by the authors. As in most areas of surgical practice committement and life long dedication are emphasized as the key(s) to success. An enquiring mind is always an advantage.

919. Understanding Intermittent Detection of Multidrug-Resistant Organisms (MDROs) in Rectally Colonized Patients

Background

MDRO detection in colonized patients may be intermittent for reasons that are incompletely understood. We examined temporal patterns of gut MDRO colonization after initial MDRO detection by rectal swab screening, and determined the relationship of culture positivity to the relative abundance of corresponding MDRO operational taxonomic units (OTUs) identified by 16S rRNA gene sequence analysis.

Methods

Rectal or fecal swabs were collected daily from MICU patients 1/11/2017-1/11/2018. First MICU admissions with ≥2 swabs and MICU stays ≥3 days were studied. Samples were cultured for vancomycin-resistant enterococci (VRE), carbapenem-resistant Enterobacteriaceae (CRE) and P. aeruginosa (CRPA), and extended-spectrum β-lactamase-producing (ESBL) Enterobacteriaceae by selective media. Resistance mechanisms were confirmed by phenotypic methods and/or PCR. Limit of detection was similar for different MDROs (24-52 CFU/sample). OTU categories corresponding to MDRO species were identified by taxonomy and BLAST. Multilevel regression models estimated the association between MDRO detection and relative abundance of the corresponding OTU.

Results

796 unique patients with 3519 swabs were studied. Median (IQR) age was 64 (51-74) years, MICU length of stay was 5 (3-8) days, and number of samples-per-patient was 3 (2-5). Following initial MDRO detection, the probability of subsequent detection varied by MDRO type, and was highest for VRE and lowest for CRPA [Figure 1]. Within each sample, we found a significant association between MDRO detection and relative abundance of the corresponding OTU [Table 1]. In contrast, relative OTU abundance in the first sample with MDRO detection was not predictive of odds of future MDRO detection (p >0.05 for all comparisons). Carriage of >1 MDRO did not affect the odds of MDRO detection in later samples.

Figure 1. Probability of Subsequent MDRO Detection after First Positive Varies by MDRO Type

Table 1. Higher Mean Corresponding OTU Relative Abundance Within Each Sample is Associated with MDRO Detection

Conclusion

MDRO culture positivity in rectally colonized patients was correlated with relative abundance of the corresponding OTU in the same sample. Serial detection of different MDRO types was variable, possibly due to distinct microbial community dynamics of different MDRO types. Intermittent failure to detect MDROs could result in misattribution of MDRO acquisition, resulting in inappropriate investigation or intervention.

Disclosures

All Authors: No reported disclosures

Estimating tadpole-detection rates using visual field surveys: effects of survey time, tadpole species and tadpole density

Context When understanding species occupancy, estimation of detection probability for the target species is often required, provided by repeated surveys. However, if the actual detection probability of the species is determined experimentally, such estimates are not required, and the reliability of the occupancy data obtained by a particular survey effort can be determined. Aims The aim of this study was to determine the detection rate of tadpoles using visual field surveys, as well as to explore the effects of survey time, species and tadpole density on the tadpole-detection rate. The suitability of visual surveys for detecting tadpole occupancy was also assessed. Methods Batch-identified tadpoles were released into several pools and repeatedly counted over successive days to calculate detection rates using visual observation. In Experiment 1, the effects of tag colour, survey time (morning vs night) and species on the detection rates of two species of tadpoles (Babina subaspera and Odorrana splendida) were examined. In Experiment 2, the effects of tadpole density on O. splendida were examined. Key results Detection rates varied by survey time, species and tadpole density; mean rates ranged from 0.2 to 0.6 for B. subaspera and 0.4 to 0.8 for O. splendida, with higher rates at night. There was a negative relationship between detection rate and tadpole density. Based on these detection rates, it was calculated that single visual surveys of O. splendida tadpoles can achieve detection probabilities near 1.0 when more than four individuals occur in a patch. Conclusions Variations in detection probability should be considered in field surveys. If the factors that cause variations in detection rates are controlled, visual surveys of tadpoles should, at least in some species, provide detection probabilities near 1.0. Implications When repeated surveys to estimate species occupancy are not practicable, determination of the actual detection probability of the target species using real detection rates provides a robust alternative approach.

Mammary Stem Cell Self-Renewal Is Regulated by Slit2/Robo1 Signaling through SNAI1 and mINSC

Tissue homeostasis requires somatic stem cell maintenance; however, mechanisms regulating this process during organogenesis are not well understood. Here, we identify asymmetrically renewing basal and luminal stem cells in the mammary end bud. We demonstrate that SLIT2/ROBO1 signaling regulates the choice between self-renewing asymmetric cell divisions (ACDs) and expansive symmetric cell divisions (SCDs) by governing Inscuteable (mInsc), a key member of the spindle orientation machinery, through the transcription factor Snail (SNAI1). Loss of SLIT2/ROBO1 signaling increases SNAI1 in the nucleus. Overexpression of SNAI1 increases mInsc expression, an effect that is inhibited by SLIT2 treatment. Increased mInsc does not change cell proliferation in the mammary gland (MG) but instead causes more basal cap cells to divide via SCD, at the expense of ACD, leading to more stem cells and larger outgrowths. Together, our studies provide insight into how the number of mammary stem cells is regulated by the extracellular cue SLIT2.

Self-regulated left-right asymmetric expression of Pitx2c in the developing mouse limb

The transcription factor Pitx2c is expressed in primordial visceral organs in a left-right (L-R) asymmetric manner and executes situs-specific morphogenesis. Here we show that Pitx2c is also L-R asymmetrically expressed in the developing mouse limb. Human PITX2c exhibits the same transcriptional activity in the mouse limb. The asymmetric expression of Pitx2c in the limb also exhibits dorsal-ventral and anterior-posterior polarities, being confined to the posterior-dorsal region of the left limb. Left-sided Pitx2c expression in the limb is regulated by Nodal signaling through a Nodal-responsive enhancer. Pitx2c is expressed in lateral plate mesoderm (LPM)-derived cells in the left limb that contribute to various limb connective tissues. The number of Pitx2c(+) cells in the left limb was found to be negatively regulated by Pitx2c itself. Although obvious defects were not apparent in the limb of mice lacking asymmetric Pitx2c expression, Pitx2c may regulate functional L-R asymmetry of the limb.

SLIT/ROBO2 signaling promotes mammary stem cell senescence by inhibiting Wnt signaling

WNT signaling stimulates the self-renewal of many types of adult stem cells, including mammary stem cells (MaSCs), but mechanisms that limit this activity are poorly understood. Here, we demonstrate that SLIT2 restricts stem cell renewal by signaling through ROBO2 in a subset of basal cells to negatively regulate WNT signaling. The absence of SLIT/ROBO2 signaling leads to increased levels of nuclear β-catenin. Robo2 loss does not increase the number of stem cells; instead, stem cell renewal is enhanced in the absence of SLIT/ROBO2 signaling. This is due to repressed expression of p16(INK4a), which, in turn, delays MaSC senescence. Together, our studies support a model in which SLITs restrict the expansion of MaSCs by countering the activity of WNTs and limiting self-renewal.

PCSK5 and GDF11 expression in the hindgut region of mouse embryos with anorectal malformations

BACKGROUND/PURPOSE

Retinoid-mediated signal transduction plays a crucial role in the embryonic development of various organs. We previously reported that retinoic acid induced anorectal malformations (ARM) in mice. GDF11 is a TGFβ superfamily molecule and is cleaved and activated by proprotein convertase subtilisin/kexin 5 (PCSK5). PCSK5 (PC5/6) mutations result in an abnormal expression of Hlxb9 and Hox genes, which include known GDF11 targets that are necessary for caudal development in vertebrate embryos. To determine a possible role of the retinoid-mediated signaling pathway in the pathogenesis of ARM, we investigated whether all-trans retinoic acid (ATRA) affected the expression patterns of PCSK5 and GDF11 in ARM-treated mouse embryos.

METHODS

Pregnant ICR-Slc mice were administered 100 mg/kg ATRA by gavage on embryonic day (E) 9.0. Embryos were harvested between days E12 and E18, and mid-sagittal sections of the hindgut region were prepared for immunohistochemistry using antibodies against PCSK5 (PC5/6) and GDF11 (GDF8/11).

RESULTS

Over 95% of the embryos treated with ATRA showed ARM, with rectourethral fistula or rectocloacal fistula, and a short tail. Furthermore, most of these embryos exhibited sacral malformations, tethered spinal cords, and presacral masses resembling those malformations found in caudal regression syndrome. By E14, normal mouse embryos formed a rectum and anus, and the somites behind the hindgut were positive for PC5/6 and GDF8/11. In contrast, in ARM embryos, the somites behind the hindgut were negative for PC5/6 and GDF8/11.

CONCLUSION

ATRA treatment affected the caudal development in mouse embryos, resulting in anorectal, sacral, and spinal malformations, and inhibited PCSK5 and GDF11 expression in the hindgut region. These findings indicate that the expression of PCSK5 and GDF11, which plays a crucial role in the organogenesis of the hindgut, was disturbed in the hindgut region when retinoid-mediated signaling was disrupted. This study offers a new insight into the pathogenesis of ARM in mice as affected by the interaction between ATRA and PCSK5/GDF11.

Establishment of a rescue program for anorectal malformations induced by retinoic acid in mice

AIMS OF STUDY

Retinoid-mediated signal transduction plays a crucial role in the embryogenesis of various organs. We previously reported the successful induction of anorectal malformations in mice using retinoic acid (RA). Retinoic acid controls the expression of essential target genes for cell differentiation, morphogenesis, and apoptosis through a complicated interaction in which RA receptors form heterodimers with retinoid X receptors. In the present study, we investigated whether the retinoid antagonist, LE135, could prevent the induction of anorectal malformations (ARMs) in mice.

METHODS

Retinoic acid was intraperitoneally administered as 100 mg/kg of all-trans RA on E9; and then the retinoid antagonist, LE135, was intraperitoneally administered to pregnant ICR strain mice on the eighth gestational day (E8), 1 day before administration of RA (group B) or on E9, simultaneously (group C) with RA administration. All of the embryos were obtained from the uteri on E18. Frozen sections were evaluated for concentric layers around the endodermal epithelium by hematoxylin and eosin staining.

RESULTS

In group A, all of the embryos demonstrated ARM with rectoprostatic urethral fistula, or rectocloacal fistula, and all of the embryos showed the absence of a tail. In group B, 36% of the embryos could be rescued from ARM. However, all of the rescued embryos had a short tail that was shorter than their hind limb. The ARM rescue rates in group B were significantly improved compared to those in group A (P < .01). In group C, 45% of the embryos were rescued from ARM, but all of the rescued embryos had short tail. The ARM rescue rate in group C was significantly improved compared to that in group A (P < .01). However, there was no significant difference in the ARM rescue rate between group B and Group C.

CONCLUSION

The present study provides evidence that in the hindgut region, RAR selective retinoid antagonist, LE135, could rescue embryos from ARM. However, the disturbance of all-trans RA acid was limited to the caudal region. Further study to establish an appropriate rescue program for ARM in a mouse model might suggest a step toward protection against human ARM in the future.

Diagnostic impact of computed tomography cholangiography and magnetic resonance cholangiopancreatography on pancreaticobiliary maljunction

BACKGROUND/PURPOSE

The aim of this study was to investigate the diagnostic potential of computed tomography cholangiography (CTC) and magnetic resonance cholangiopancreatography (MRCP) in children with pancreaticobiliary maljunction (PBM).

METHODS

Fifty-three children with PBM were consecutively treated between 1997 and 2009. Among them, the patients who underwent CTC and/or MRCP preoperatively were enrolled in this study. Computed tomography cholangiography was examined after infusion of meglumine iodoxamate with subsequent 3-dimensional rendering. The visualization of the biliary and pancreatic duct systems was evaluated and compared with that visualized with MRCP. The findings of direct cholangiography were used as the standard of reference.

RESULTS

Of the 53 cases with PBM, 17 cases were examined by CTC, 10 cases by MRCP, and 17 with both. The extrahepatic bile tract was visualized in 32 (94.1%) of 34 patients in CTC and in all 27 patients in MRCP. The intrahepatic bile duct was more frequently demonstrated by MRCP than by CTC (96.3% vs 70.6%, P = .02). Pancreaticobiliary maljunction was noted in 13 (38.2%) of 34 with CTC and in 12 (44.4%) of 27 with MRCP. The minimum age for visualization of PBM was at 10 months in CTC and at 1 year and 11 months in MRCP, respectively. The main pancreatic duct was more frequently visualized by MRCP than by CTC (81.5% vs 8.8%, P < .001).

CONCLUSIONS

Magnetic resonance cholangiopancreatography provides superior visualization of the intrahepatic duct and the pancreatic system when compared with CTC. However, it is still challenging to perform a good-quality examination in young infant. The great advantage of CTC is its ability to produce high-quality images without respiratory artifacts and that it allows accurate assessment of the presence of PBM equivalent to MRCP.

Diagnosis and treatment of pancreaticobiliary maljunction in children

Pancreaticobiliary maljunction (PBM), which may be called by synonymous terms such as "anomalous arrangement of the pancreaticobiliary duct" or "anomalous union of biliopancreatic ducts," is defined as an anatomical maljunction of the pancreatic duct and the biliary duct outside of the duodenal wall beyond the influence of the sphincter of Oddi. Pancreaticobiliary maljunction is classified into three groups according to the type of the pancreaticobiliary junction. Pancreaticobiliary maljunction is diagnosed mainly by endoscopic retrograde cholangiopancreatography; however, in pediatric patients, it may be diagnosed by intraoperative cholangiography, and more recently has been diagnosed by computed tomographic cholangiography or contrast-enhanced helical computed tomography. Children with PBM without choledochal cysts usually do not show any symptoms except for abdominal pain and hyperamylasemia. Pancreaticobiliary maljunction is considered to be a major risk factor for biliary tract malignancy. In patients with PBM, free reflux of pancreatic juice into the biliary tract might induce biliary tract damage and biliary carcinogenesis. Thus, total resection of the extrahepatic bile duct and hepaticojejunostomy are recommended in children diagnosed with PBM with choledochal cyst. Early diagnosis and early surgical treatment provide a good prognosis with few complications. In addition, successive follow-up is necessary for early detection of biliary tract malignancy, especially in patients demonstrating postoperative complications.

Left-right asymmetry in the level of active Nodal protein produced in the node is translated into left-right asymmetry in the lateral plate of mouse embryos

Left-right (L-R) asymmetry in the mouse embryo is generated in the node and is dependent on cilia-driven fluid flow, but how the initial asymmetry is transmitted from the node to the lateral plate has remained unknown. We have now identified a transcriptional enhancer (ANE) in the human LEFTY1 gene that exhibits marked L>R asymmetric activity in perinodal cells of the mouse embryo. Dissection of ANE revealed that it is activated in the perinodal cells on the left side by Nodal signaling, suggesting that Nodal activity in the node is asymmetric at a time when Nodal expression is symmetric. Phosphorylated Smad2/3 (pSmad2) indeed manifested an L-R asymmetric distribution at the node, being detected in perinodal cells preferentially on the left side. This asymmetry in pSmad2 distribution was found to be generated not by unidirectional transport of Nodal but rather as a result of L<R asymmetric expression of the Nodal antagonist Cerl2. For various mutant embryos examined, the asymmetry in pSmad2 distribution among the perinodal cells closely matched that in lateral plate mesoderm (LPM). However, autocrine-paracrine Nodal signaling in perinodal cells is dispensable for L-R patterning of LPM, given that its inhibition by expression of dominant negative forms of Smad3 or ALK4 was still associated with normal (left-sided) Nodal expression in LPM. Our results suggest that LPM is the direct target of Nodal secreted by the perinodal cells, and that an L>R distribution of active Nodal in the node is translated into the asymmetry in LPM.

OK-432 therapy for chylous pleural effusion or ascites associated with lymphatic malformations

OK-432 therapy is effective for the treatment of macrocystic lymphatic malformations (LMs), but the optimal management of patients with microcystic LMs associated with large chylous pleural effusions or chylous ascites is not resolved. We performed thoracoscopic- or laparoscopic-guided injection of OK-432 for 2 patients with diffuse microcystic LMs accompanied by refractory chylous pleural effusion or chylous ascites. Both cases responded well to OK-432 therapy with improvement/resolution of fluid collections and associated symptoms. We recommend the use of OK-432 therapy as a promising treatment for microcystic LMs with functionally significant lymphatic fluid collections.

Impact of age at diagnosis on clinical features in children with anomalous arrangement of the pancreaticobiliary duct

AIMS

In patients with an anomalous arrangement of the pancreaticobiliary duct (AAPBD), clinical presentations may differ between infants and older children. The optimal timing of surgery remains controversial, particularly in early infancy. The aim of this study was to evaluate the clinicopathological features and clinical outcomes using comparative methods between infants and older cases. MATERIALS AD METHODS: From 1983 to 2007, a total of 85 consecutive children with AAPBD were treated at our institute. They included 46 with the cystic type, 33 with the fusiform type, and 6 with the non-dilatation type. These patients were divided into 2 age groups: "infant" (n=9), <12 months old; and "older", >1 year old (n=76). A retrospective study was performed.

RESULTS

Mean age was 5.2 months (range, 8 days-11 months) in the infant group and 5.2 years (range, 1.2-17.3 years) in the older group. Jaundice was significantly more frequent in the infant group ( P<0.05), whereas abdominal pain was more common in the older group ( P<0.001). Bleeding tendencies such as cranial hemorrhage or bloody stools were noted in only 3 infants. In terms of liver histology, liver cirrhosis was observed in 2 infants, one of whom was a 3-month-old girl with severe jaundice resulting in living-donor liver transplantation, despite bile drainage. A single postoperative death occurred due to an adenocarcinoma arising in a choledochal cyst in a 12-year-old girl.

CONCLUSIONS

Problems characteristic of infantile AAPBD were a severe bleeding tendency and irreversible liver cirrhosis, which could develop as young as 3 months old. The surgical recommendation for infantile AAPBD is thus early surgery before the age of 3 months to prevent liver failure.

Usefulness of magnetic resonance imaging for congenital prepubic fistula

Congenital prepubic fistula is a rare congenital anomaly. Complete removal of the fistular tract remains challenging because of the complicated course. Although conventional fistulography has been used widely as a diagnostic tool for congenital prepubic fistula, more detailed information such as accurate localization of the fistular end or relative position to the urinary tract cannot be preoperatively obtained because the conventional contrast studies have insufficient capability. In this article, we reported the complete removal of congenital prepubic fistula based on preoperative magnetic resonance imaging findings, especially T2-weighted imaging. Magnetic resonance imaging clearly displayed not only the tract of the prepubic fistula originating from a subcutaneous cyst but also the tract extending and ending near the top of the urinary bladder.

Clinical course of obstructive jaundice associated with operated meconium peritonitis in neonates

BACKGROUND/PURPOSE

Meconium peritonitis (MP) may induce prolonged cholestasis after laparotomy. In this study, we investigated the postoperative clinical course of MP retrospectively and discuss the relationship between MP and the development of obstructive jaundice, including biliary atresia (BA).

PATIENTS AND METHODS

Between 1979 and 2008, 23 infants with MP underwent laparotomy at our institution. Eleven of the 23 infants (47.8%) developed obstructive jaundice postoperatively. The medical charts of these 11 infants were reviewed.

RESULTS

The causative disease underlying MP included jejunoileal atresia in 10 and cloacal anomaly in 1. Of these 11 infants, 4 had acholic stools. Nine of the 11 improved with conservative management including an expectant approach, choleretic agents, and exchange blood transfusion. To differentiate the diagnosis from BA, open cholangiography was required in 2 cases following negative HIDA scintigraphy and a small gallbladder on ultrasonography. One of these 2 cases was diagnosed as BA and underwent hepatic portoeneterostomy simultaneously, after which the infant became jaundice free.

CONCLUSIONS

Postoperative cholestasis after MP was a transient condition in most cases. However, ultrasonography and HIDA scintigraphy should be performed to differentiate BA in infants with MP who show prolonged jaundice with acholic stools.

Predicting factors on the occurrence of cystic dilatation of intrahepatic biliary system in biliary atresia

PURPOSE

Cystic dilatation of intrahepatic biliary system (CDIB) is an intractable complication of biliary atresia (BA). In this study, we investigated the predicting factors of CDIB development after jaundice resolved following hepatoportoenterostomy (HPE).

METHODS

From 1988 to 2008, 28 (80.0%) of 35 uncorrectable type of BA patients became jaundice-free after HPE. Of these 28 patients, this retrospective study included comparisons of the preoperative characteristics, postoperative jaundice period, cumulative steroid dose, outcome, and liver fibrosis grade at the time of HPE between CDIB-positive and -negative groups, divided by postoperative ultrasonography findings.

RESULTS

There were no differences between groups in perioperative characteristics. Liver fibrosis in the CDIB-positive group (n = 7) included grade II in two patients, grade III in four patients, and grade IV in one patient. On the contrary, the CDIB-negative group (n = 21) included 8, 11, 2, and 0 patients with grades I-IV, respectively, with a significant difference (p < 0.05) between groups. Survival rate with native liver in CDIB-positive group was significantly lower than that in CDIB-negative group (p < 0.05).

CONCLUSION

Postoperative CDIB might be a poor prognostic factor, and the liver fibrosis grade at the time of HPE could be helpful to predict the development of CDIB after HPE.

Long-term outcomes after hepaticojejunostomy for choledochal cyst: a 10- to 27-year follow-up

INTRODUCTION

Choledochal cyst (CC) is closely associated with anomalous arrangement of the pancreaticobiliary duct, which is considered a high-risk factor for biliary tract malignancy. Early diagnosis and early treatment for CC could lead to a good prognosis. This study investigated late complications and long-term outcomes after surgery for CC.

PATIENTS AND METHODS

Fifty-six patients with CC and over 10 years of postoperative follow-up were analyzed retrospectively. All patients had undergone total resection of the extrahepatic bile duct and hepaticojejunostomy.

RESULTS

Six patients showed liver dysfunction manifested in the first 10 years after surgery, but all returned to normal thereafter. Dilatation of intrahepatic bile ducts persisted in 6 postoperatively, and in 3, this was still apparent more than 10 years after. Recurrent abdominal pain was encountered in 3, 1 had pancreas divisum with a pancreatic stone, and 1 had adhesive small bowel obstruction. Two patients developed biliary tract malignancy. A 14-year-old girl died of recurrent common bile duct cancer 2 years after the initial resection of CC with adenocarcinoma. A 26-year-old man with repeated cholangitis owing to multiple intrahepatic bile stones developed cholangiocarcinoma 26 years after the initial resection of CC. Event-free survival rate and overall survival rate were 89% (50/56) and 96% (54/56), respectively.

CONCLUSIONS

Choledochal cyst generally has an excellent prognosis with early total resection and reconstruction. Long-term surveillance for the development of malignancy is still essential, especially if there is ongoing dilatation of the intrahepatic bile duct or biliary stones.

Choledochal cyst associated with duodenal atresia: case report and review of the literature

We report a rare case of choledochal cyst (CC) associated with congenital duodenal atresia (DA) and annular pancreas (AP). A girl was born at 37 weeks of gestation weighing 2,974 g with a prenatal diagnosis of DA. She underwent a duodenoduodenostomy for type III DA with an AP 1 day after birth. At 4 years of age, she was admitted for evaluation of cholangitis and pancreatitis. Radiological studies demonstrated a fusiform-type CC with pancreaticobiliary maljunction (PBMJ). Excision of the CC and hepaticojejunostomy were performed. The patient was discharged without complications. Despite the fact that CC, DA, and AP are embryologically closely related entities, to the best of our knowledge, only eight such cases have been documented. We must be aware of the possible combination of CC in the follow-up of the patients with DA associated with AP.

Bombesin can minimize impairments of interstitial cells of Cajal induced by FK506 in small bowel transplantation

PURPOSE

Interstitial cells of Cajal (ICC) are known as intestinal pacemaker cells and express c-kit on their membrane. Previously, we reported that FK506 had neurotoxicity to enteric ganglia, and bombesin (BBS) preserved them against FK506. The aim of this study was to investigate whether ICC was impaired by FK506 and whether ICC was preserved by BBS against FK506.

METHODS

Twelve rats underwent allogeneic SBTx heterotopically and were divided into 2 groups as follows: group A underwent SBTx with FK506 and group B with FK506/BBS. All rats were administered FK506 daily. Either BBS or normal saline was infused continuously from day 14 to 28. Analysis of ICC was performed immunohistochemically with c-kit. Interstitial cells of Cajal were evaluated by counting the number of c-kit-positive clusters in each graft.

RESULTS

The expression of c-kit accumulated around 60% of PGP9.5-positive enteric ganglia. The number of c-kit-positive clusters in group A was 22.3 +/- 5.5 clusters per cross section (C/CS) and that in group B was 36.3 +/- 5.1 C/CS. Interstitial cells of Cajal were well preserved in group B. There was a significant difference between groups A and B (P <.001).

CONCLUSION

Interstitial cells of Cajal were impaired by FK506 in allografts, and BBS could minimize the impairment of ICC against FK506.

A novel PAX3 rearrangement in embryonal rhabdomyosarcoma

Rhabdomyosarcoma is the most common soft tissue tumor seen in children and young adults, and it can be classified into 2 major histological subtypes, alveolar and embryonal. In the alveolar subtype, 2 recurrent chromosomal translocations, t(2;13)(q35;q14) and its variant t(1;13)(p36;q14), have been identified as the specific cytogenetic abnormalities. These translocations produce the PAX3-FOXO1 and PAX7-FOXO1 fusion genes, respectively. In the embryonal subtype, however, no recurrent chromosomal abnormalities have been identified. In this study, we analyzed the complex chromosomal translocation in one case with embryonal rhabdomyosarcoma by means of spectral karyotyping (SKY) and identified a novel translocation involving chromosome band 2q35, which is the locus of PAX3 gene. Furthermore, we identified the novel PAX3 rearrangement using fluorescence in situ hybridization (FISH) analysis. Additional identification of the partner gene may help disclose the molecular mechanism of the development of this embryonal subtype.

Congenital anomalies induced by triamcinolone acetonide in murine embryos

INTRODUCTION

We have studied the morphogenesis of anorectal malformations in mice using retinoids. Several investigators have reported an interaction between glucocorticoids and retinoids. It was supposed that glucocorticoids had some effects on the morphogenesis of murine embryos similar to retinoids. Therefore, we investigated alterations in the morphogenesis of murine embryos after triamcinolone acetonide (TAC) administration.

MATERIAL AND METHODS

TAC was administered in a single dose (15 mg/kg or 30 mg/kg body weight) to pregnant ICR-SLC mice on embryonic day 7 (E7), 8, 9, and 10. They were sacrificed on E18, and fetuses were examined for internal and external malformations. Randomly chosen fetuses were embedded in paraffin for immunohistochemical staining of the glucocorticoid receptor (GR).

RESULTS

The groups given 15 mg/kg TAC had one peak in the incidence of cleft palate on E9 (100 %) and the groups given 30 mg/kg TAC showed a biphasic pattern in the incidence of cleft palate on E7 and E10. No other anomalies were found. GR expression was marked in the subepithelial layer of palatal processes in the treated specimens.

CONCLUSION

The group given 15 mg/kg TAC on E9 provided a good model of cleft palate in ICR-SLC mice, and cleft palate was probably induced by various factors including disturbance of the bone morphogenetic protein (BMP) signaling pathway, shown by GR overexpression.

Development of bile duct cancer in a 26-year-old man after resection of infantile choledochal cyst

Anomalous arrangement of the pancreaticobiliary duct is considered to be a high-risk factor for biliary tract malignancy. We report a case of intrahepatic cholangiocarcinoma in a 26-year-old man after total resection of choledochal cyst with anomalous arrangement of the pancreaticobiliary duct at the age of 5 months. He had been doing well after total resection of the choledochal cyst; however, he suddenly presented with a spiky fever and abdominal pain in the right upper quadrant at the age of 26 years. Computed tomographic scan and percutaneous transhepatic cholangioscope revealed multiple stones and stenosis of the hepatic duct and the left intrahepatic bile duct. Histologic examination of a biopsy specimen obtained from the stenotic site showed adenocarcinoma of the intrahepatic bile duct. Left lobectomy with re-reconstruction by right hepaticojejunostomy was performed, and his postoperative course was uneventful. One year after the operation, however, he died of carcinomatous peritonitis with recurrence of cholangiocarcinoma. This report warns us that bile stasis owing to stenosis of the intrahepatic bile duct and repeated cholangitis with multiple stones are high-risk factors for carcinogenesis of the intrahepatic bile duct even after total resection of the infantile choledochal cyst.

Horizontal basal cells are multipotent progenitors in normal and injured adult olfactory epithelium

The mammalian olfactory neuroepithelium provides a unique system for understanding the regulation of neurogenesis by adult neural stem cells. Recently, mouse horizontal basal cells (HBCs) were identified as stem cells that regenerate olfactory receptor neurons (ORNs) and non-neuronal cell types only after extensive injury of the olfactory epithelium (OE). Here we report a broader spectrum of action for these cells. We show that even during normal neuronal turnover, HBCs actively generate neuronal and non-neuronal cells throughout adulthood. This occurs in a temporally controlled manner: an initial wave of HBC-derived neurogenesis was observed soon after birth, and a second wave of neurogenesis was observed at 4 months of age. Moreover, upon selective depletion of mature ORNs by olfactory bulbectomy, HBCs give rise to more neurons. Our findings demonstrate a crucial role for HBCs as multipotent progenitors in the adult OE, acting during normal neuronal turnover as well as in acute regeneration upon injury.

Significance of ductal plate malformation in the postoperative clinical course of biliary atresia

PURPOSE

Ductal plate malformation (DPM) is one of the etiologic theories for the development of biliary atresia (BA). In this study, we investigated the significance of DPM in the postoperative clinical course of BA, especially as a predictive factor of jaundice clearance.

METHODS

Between 1988 and 2005, 31 patients with uncorrectable BA underwent hepatoportoenterostomy and steroid therapy. Immunohistochemistry was used to characterize biliary structures using cytokeratin 19. Specimens were defined as DPM-positive if a concentric cellular arrangement was detected. This retrospective study included comparisons of preoperative characteristics, the postoperative jaundice period, and cumulative steroid doses between patients with and without DPM.

RESULTS

Of the 31 patients with uncorrectable BA, 25 (80.6%) became jaundice-free. Ductal plate malformation was detected in 11 (35.5%) of the 31. Between the 2 groups, there were no differences in preoperative characteristics or in the postoperative jaundice-free rate. Among those who became anicteric, the postoperative jaundice period was 145.3 +/- 69.9 days in the DPM-positive group (n = 9) and 81.8 +/- 44.7 days in the DPM-negative group (n = 16) (P < .05). The total administered steroids were 149.7 +/- 78.2 and 95.0 +/- 60.2 mg/kg, respectively (P = .09).

CONCLUSION

Ductal plate malformation may disturb bile flow and require more steroid to improve bile drainage. Therefore, the presence of DPM in the liver predicts poor bile flow after hepatoportoenterostomy in infants with BA.

Bowel function after surgery for anorectal malformations in patients with tethered spinal cord

Tethered spinal cord (TC) is an anomaly frequently recognized in association with anorectal malformations (ARM). However, the influence of TC on bowel function in children with ARM remains unknown. Furthermore, there are few studies that have assessed anorectal function in children with ARM and TC. The aim of this study was to evaluate anorectal function in ARM patients with TC using clinical assessment and anorectal manometry. Among 258 patients with ARM, this retrospective investigation included 35 patients who underwent spinal magnetic resonance imaging (MRI) after surgery for ARM. The patients were divided into two groups based on the presence or absence of TC, and bowel function was assessed by Kelly's clinical score and anorectal manometry. Tethered cord was found in nine of the 35 patients (26%) with ARM. Of the ARM patients, TC was noted in four of 11 (36%) with high type anomalies, one of 8 (13%) with intermediate type anomalies, two of 14 (14%) with low type anomalies, and two of two patients (100%) with cloacal anomalies. Kelly's clinical score did not significantly differ between the two groups. However, two of the nine patients with TC had poor bowel function (Kelly's score; 2-0 points). On the contrary, patients without TC did not have poor bowel function. Anorectal manometry did not show a significant difference between patients with and without TC. However, the two patients with TC who had poor bowel function by Kelly's score had low anal resting pressure, which was essential for achieving fecal continence. In conclusion, the present study showed that tethered cord was more frequently found in patients with more severe anorectal anomalies. Patients with TC were more likely to have poor bowel function, but this did not reach statistical significance.

Preoperative evaluation of the aberrant artery in intralobar pulmonary sequestration using multidetector computed tomography angiography

Intralobar pulmonary sequestration is a rare congenital malformation of the lung, and identification of the aberrant artery from the systemic circulation to the sequestered lung is crucial in definitive surgery. Nowadays, various noninvasive imaging modalities such as helical computed tomography, magnetic resonance imaging, and color Doppler sonography have been developed. Among them, multidetector computed tomography angiography, which allows simultaneous imaging of the aberrant artery and venous drainage, has the potential to become the first-line examination in the preoperative assessment of pulmonary sequestration. In this article, we describe 2 cases of intralobar pulmonary sequestration, in which multidetector computed tomography angiography was useful in the preoperative management and surgery was successfully performed.

Continuous remission in an infant with chest wall malignant rhabdoid tumor after relapse

Malignant rhabdoid tumor (MRT) is a highly aggressive tumor that occurs in infancy or childhood. The prognosis, especially in infants, is very poor. Here we report the long-term survival of a 5-month-old boy with MRT that arose from the chest wall. After total resection of the tumor, the patient was given 4 cycles of doxorubicin, vincristine, and cyclophosphamide, alternating with ifosfamide and etoposide. After 18 months off therapy, he had a local recurrence at the same site. After a second total resection, he was given additional chemotherapy with 30.6-Gy local irradiation. No further recurrence has been observed for 5 years since the second complete remission. Currently, he is alive and well at 7.5 years post-onset. Our experience in this case suggests a fundamental strategy of successful treatment of this highly malignant pediatric tumor: (1) complete resection of the localized tumor, (2) intensive multiagent chemotherapy for the minimal disseminated disease, and (3) radiotherapy for local control of the disease.

The inv mouse as an experimental model of biliary atresia

BACKGROUND/PURPOSE

The causation of biliary atresia (BA) remains unclear. However, ductal plate malformation (DPM), maldevelopment of the intrahepatic bile ducts, is 1 of the preferred theories. The inv homozygous mouse (inv mouse), created by insertional mutagenesis, shows situs inversus and jaundice. This study investigated whether the inv mouse could be an experimental model of human BA.

METHODS

In the inv mice (n = 12) and wild-type littermates (n = 12), we examined the liver function and morphologic changes in the biliary tract through serum biochemical study and morphological study.

RESULTS

The level of serum total and conjugated bilirubin in the inv mouse was 8.1 +/- 3.8 and 4.4 +/- 2.4 mg/dL, respectively, significantly higher than in the wild type. Macroscopically, 11 (92%) of 12 inv mice had situs inversus, and 3 (25%) of 12 mice had preduodenal portal vein. Histologically, the continuity of the extrahepatic bile duct was preserved. However, DPM, showing proliferative biliary epithelium around the intrahepatic portal vein, was found in the liver of the inv mouse.

CONCLUSION

In the inv mouse, the pathologic changes in DPM were found in the intrahepatic biliary system, which were observed in some clinical cases of BA. Therefore, the intrahepatic biliary system of the inv mouse could be an experimental model of human BA with DPM.

Clinical significance of the confluence of the cystic duct in patients with anomalous arrangement of the pancreaticobiliary duct

BACKGROUND/PURPOSE

In anomalous arrangement of the pancreaticobiliary duct (AAPBD), there is anatomical diversity of the cystic duct. In this study, we evaluated the influence of the level of insertion of the cystic duct into the extrahepatic bile duct on the pathophysiology of AAPBD.

METHODS

Thirty-two children with AAPBD were examined using cholangiopancreatography. If the cystic duct entered the hepatic duct at the lower middle point of the extrahepatic bile duct, it was defined as low confluence; otherwise, it was considered as high confluence. Clinical details and radiological variables were compared between these 2 groups.

RESULTS

Low confluence was noted in 8 of the 32 patients. Seven of the 8 had fusiform-type or nondilatation-type choledochus, and the cystic-type was significantly less frequent than in the high-confluence group. The diameter of the common bile duct was significantly smaller and the main pancreatic duct was significantly greater than in the high-confluence group. Pancreatitis was more common and biliopancreatic reflux on computed tomography combined with intravenous infusion cholangiography was more often seen in the low-confluence group than in the high-confluence group.

CONCLUSIONS

Bile juice could regurgitate into the pancreatic duct via the low confluence of the cystic duct, resulting in severe pancreatitis in patients with AAPBD.

Effects of herbal medicine Dai-Kenchu-to on anorectal function in children with severe constipation

AIM

We administered the herbal medicine Dai-Kenchu-To (DKT) to children with severe chronic constipation or with severe constipation after surgery for anorectal malformations. We then objectively assessed the effect of DKT on anorectal function by manometric study in addition to using a clinical scoring system.

PATIENTS AND METHODS

Ten children with severe chronic constipation and 5 children with severe constipation after surgery for anorectal malformations were assessed. These 15 children received 0.3 g/kg/day of DKT for periods ranging from 3 months to 1 year. We objectively assessed their bowel function, sphincter function and rectal reservoir function by anorectal manometry and clinical scoring.

RESULTS

In 10 children with severe chronic constipation, the clinical score after administration of DKT (7.2 +/- 0.8) improved significantly compared with that before administration of DKT (4.6 +/- 2.9) (p < 0.02). The threshold sensation volume and the maximum tolerable volume after administration of DKT significantly (p < 0.05; p < 0.01) decreased (128 +/- 63 ml vs. 69 +/- 18 ml; 229 +/- 99 ml vs. 144 +/- 47 ml), and rectal compliance after administration of DKT also significantly (p < 0.05) decreased (12.4 +/- 10.9 ml/cmH(2)O vs. 4.7 +/- 3.9 ml/cmH(2)O).

CONCLUSION

The present study demonstrated that DKT had a favorable clinical effect on severe constipation in children, and anorectal manometry showed an improvement in their rectal reservoir functions. It appears that the results were secondary to DKT-stimulated peristalsis of the intestine, which promoted regular bowel habits.

The significance of steroid therapy after hepatoportoenterostomy in infants with biliary atresia

PURPOSE

Despite improvements in the surgical management of biliary atresia (BA), it is still difficult to maintain good bile flow. In the present study, we examined steroid therapy and determined the appropriate dose to achieve freedom from jaundice after hepatoportoenterostomy (HPE) in the uncorrectable type of BA.

METHODS

A retrospective clinical analysis was done in 23 of 29 (79 %) cases who had become jaundice-free after undergoing HPE with steroid therapy between 1988 and 2004. A correlation between the total or mean steroid dose and the postoperative jaundice period (serum total bilirubin > 1.0 mg/dl) was evaluated using linear regression analysis. The regimen was as follows: prednisolone was given intravenously, starting with 3 to 5 mg/kg/day, and then gradually tapered with repetition until freedom from jaundice was achieved.

RESULTS

Age at HPE was 72 +/- 20 days (mean +/- SD), and the postoperative jaundice period was 108 +/- 68 days. Total and mean steroid doses were 118 +/- 73 mg/kg and 1.31 +/- 0.8 mg/kg/day, respectively. There was no correlation between the total steroid dose and the period of jaundice. However, there was a significant correlation between the mean steroid dose and the period of jaundice (p = 0.021).

CONCLUSION

A high mean dose of steroids could shorten the jaundice period after HPE in the uncorrectable type of BA.

Significance of the anomalous arrangement of the pancreaticobiliary duct in the etiology of biliary atresia

BACKGROUND/PURPOSE

The anomalous arrangement of the pancreaticobiliary duct (AAPBD) is one theory used to explain the etiology of biliary atresia. We investigated whether AAPBD could be involved and evaluated its significance for the etiology of biliary atresia.

MATERIALS AND METHODS

Of 43 patients with biliary atresia, the area between the common bile duct and the duodenum could be visualized by operative cholangiogram in 5 patients with an uncorrectable type of biliary atresia. Three of the 5 showed an anomalous arrangement of the pancreaticobiliary duct. In these 3 patients, the type of anomalous arrangement of the pancreaticobiliary duct and the length of the common channel were studied by operative cholangiogram. Histological findings of the gallbladder and the common bile duct were examined in addition to the measurement of the serum amylase levels.

RESULTS

All 3 patients showed AAPBD with the P-C type of pancreaticobiliary junction. The length of the common channel ranged from 7 mm to 12 mm. Two of the 3 cases did not show an elevated serum amylase level. Epithelial hyperplasia of the gallbladder was observed in one patient, while the other two showed no hyperplasia. Inflammatory changes in the mucosa of the gallbladder and the common bile duct were not remarkable in these 3 patients.

CONCLUSIONS

From these results it seems that AAPBD in biliary atresia might not be an etiological factor for atresia of the extrahepatic bile duct, but might be an associated anomaly in biliary atresia. Other factors should be examined to clarify the etiological factor leading to lumenal obstruction of the extrahepatic bile duct.

Social quality of life for adult patients with anorectal malformations

BACKGROUND/PURPOSE

Pediatric surgeons who performed the initial surgery on anorectal malformations (ARM) lose contact with the patients as they become adults. In the present study, we examined 20- to 40-year-old adult patients with a history of surgery for ARM and analyzed them from the points of social quality of life.

PATIENTS AND METHODS

Twenty-nine patients with ARM, aged 20 to 40, were surveyed by questionnaire or personal interview. Thirteen with high-type and 9 with intermediate-type anomalies underwent abdominoperineal rectoplasty, and 7 with low-type anomalies underwent perineoplasty between 1965 and 1985. Responses were analyzed from the perspectives of bowel, urinary, and sexual functions and social activity.

RESULTS

One third of patients with high- or intermediate-type anomalies occasionally complained of fecal soiling. However, the other patients gained good bowel function and enjoyed occupational or student life without problems. Fecal soiling was the key factor disturbing occupational life, although the problem remained within a socially manageable level. All of the patients with ARM had normal urinary function. Three of the 18 male patients had sexual problems such as erectile or ejaculatory dysfunction because of associated genitourinary anomalies. Nine of the 11 female patients had regular menstruation and the other 2 had irregular menstrual periods. Five female patients were married and 4 of the 5 had children (1-5 children). Modes of delivery were normal vaginal delivery in 8 and cesarean section in 1. Only one of the 5 had a slight sacral anomaly. However, she had no apparent abnormality of bladder function and got through pregnancy and delivery without difficulty.

CONCLUSION

One third of adult patients with high- or intermediate-type anomalies after abdominoperineal rectoplasty had some problems in bowel function. Fecal soiling was the key factor that disturbed their occupational life. Most of the patients had normal urinary and sexual functions if they did not have associated genitourinary anomalies and enjoyed social activities.

Bleeding tendency as a first symptom in children with congenital biliary dilatation

AIM OF THE STUDY

Although a bleeding tendency as a first symptom is a critical condition in congenital biliary dilatation (CBD), the clinical details of this symptom remain unclear. We assessed this condition in children with CBD in this paper.

MATERIALS AND METHODS

Sixty-five children with CBD were treated at our institute between 1983 and 2004. The children, initially presenting with bleeding manifestations such as intracranial hemorrhage and bloody stools, were defined as the bleeding group, and the remaining children with digestive symptoms such as abdominal pain and vomiting were defined as the digestive group. The clinical features were compared between these two groups.

RESULTS

In 6 of the 65 cases, bleeding manifestations were noted (9.2 %). All six had cystic-type choledochal dilatation. The mean age of the bleeding group was significantly younger than that of the digestive group, and bleeding was more frequent, especially in infants less than 12 months of age. In a laboratory study, the bleeding group showed a more prolonged blood coagulation time than the digestive group did. Serum amylase and lipase levels in the bleeding group were almost normal, while those in the digestive group were significantly higher. The direct bilirubin level in the bleeding group was significantly higher than that in the digestive group.

CONCLUSIONS

Disturbed blood coagulation due to vitamin K deficiency related to cholestasis results in a bleeding tendency in children with CBD. Therefore, pediatric surgeons should be aware of this rare but critical condition which can be prevented by rapid and precise treatment with vitamin K supplementation.

Bombesin can rescue the enteric ganglia from FK506 neurotoxicity on small bowel transplantation

BACKGROUND/PURPOSE

FK506 has been reported to have neurotoxic effects. The aim of this study was to investigate whether FK506 causes neurotoxic effects on the transplanted graft enteric ganglia (TGEG) and whether bombesin (BBS) can prevent such atrophy.

METHODS

Thirty rats heterotopically underwent small bowel transplantation and were divided into 5 groups as follows: group A, syngraft (SYN) alone; group B, SYN with FK506; group C, SYN with FK506 and BBS; group D allograft with FK506; group E, allograft with FK506 and BBS. From postoperative days 14 to 28, either BBS or normal saline was administered continuously. All recipients except for group A received FK506 daily. The ganglionic count was obtained by counting the number of protein gene product 9.5 immunohistochemically stained ganglia in the cross sections of each graft.

RESULTS

The number of TGEG in groups A, B, and C was 69.7 +/- 6.0, 51.5 +/- 7.7, and 84.8 +/- 10.2 ganglia per cross section, respectively. There was a significant difference between each group (P < .001). The number of TGEG in groups D and E was 44.6 +/- 7.5 and 65.1 +/- 9.5 ganglia per cross section, respectively. There was a significant difference between the 2 groups (P < .001).

CONCLUSIONS

FK506 causes severe neurotoxicity in transplanted grafts, and BBS protects graft enteric ganglia against the neurotoxic effects of FK506.

FK506 Induces the Atrophy of Enteric Ganglia in Small Bowel Transplantation, Which Can Be Prevented by the Neuropeptide Bombesin

PURPOSE

FK506, which is widely used for immunosuppression, is reported to have neurotoxicity. However, its neurotoxicity for transplanted graft enteric ganglia (TGEG) has never been reported. The aim of this study was to investigate whether FK506 has a neurotoxic effect on TGEG, and whether bombesin (BBS) prevents such atrophy.

METHODS

Eighteen rats that underwent syngertic heterotopic small bowel transplantation (SBTx) using a cuff method were divided into three groups of six rats each; A: SBTx alone, B: SBTx with FK506, C: SBTx with FK506/BBS. Either BBS (10 mg/kg/d) or normal saline was infused continuously from day 14 to 28. Rats in groups B and C were administered FK506 (0.32 mg/kg/day, intramuscularly) daily. Analysis of TGEG was performed using immunohistochemistry with protein gene product (PGP) 9.5. The ganglionic number was obtained by counting PGP9.5-positive ganglia in each graft.

RESULTS

The number of TGEG were reduced significantly in group B (51.5 +/- 7.7 ganglia per cross section (G/CS)) compared with group A (69.7 +/- 6.0 G/CS), but were well preserved in group C (84.8 +/- 10.2 G/CS). There were significant differences between groups B and C (P < .001) and also between groups A and C (P < .001).

CONCLUSION

FK506 showed severe neurotoxicity on transplanted grafts, and bombesin could rescue TGEG against FK506 neurotoxicity.

Prevention of Warm Ischemic Injury by Neuropeptide Bombesin in Small Bowel Transplantation

PURPOSE

This study investigated whether preoperative administration of neuropeptide bombesin (BBS) had a protective effect against IR/I and subsequent acute rejection.

METHODS

Allogeneic SBTx was performed heterotopically in rats (n = 18). That were administered FK506 (0.32 kg/d) daily. The rats were divided into three groups of six rats each: group 1, BBS(-)5: warm ischemic time (WIT); 5 minutes without BBS; group 2, BBS(-)15: WIT; 15 minutes without BBS; group 3, BBS(+)15: WIT; 15 minutes with BBS. The specimens were obtained from the stoma site at 1 hour after reperfusion and on postoperative days (PODs) 1 and 7. The graft mucosal state and degree of acute rejection were evaluated by H and E staining. The apoptotic cells in the crypt lesion were evaluated using TUNEL immunohistochemistry. An apoptotic index (AI) was calculated for quantitative analysis.

RESULTS

H and E staining revealed that on POD 1 the mucosal villi were shortened in the BBS(-)15 group compared with the other two groups. One hour after reperfusion, the AI in BBS(-)15 group was 125.0 per thousand +/- 37.2 per thousand, which was significantly higher (P < .05) than that in the BBS(-)5 group (32.6 per thousand +/- 5.0 per thousand) or the BBS(+)15 group (32.0 per thousand +/- 3.0 per thousand). On POD 7, the AI in the BBS(-)15 group was 63.7 per thousand +/- 5.03 per thousand, which was significantly higher (P < .05) than in the BBS(-)5 (17.3 per thousand +/- 4.6 per thousand) or the BBS(+)15 group (12.3 per thousand +/- 3.06 per thousand).

CONCLUSIONS

Even a short WIT of 15 minutes induced considerable allograft mucosal damage, which also heightened the possibility of acute rejection. Exogenous BBS prevented mucosal damage by IR/I and was also beneficial to prevent acute rejection.

Neuroendocrine-Immune Modulation May Be Useful for Allograft-Specific Immunosuppression in Small Bowel Transplantation

PURPOSE

The authors have previously demonstrated that the neuropeptide bombesin (BBS) prevented allograft mucosal atrophy under tacrolimus (TRL) immunosuppression for rats small bowel transplantation (SBT). The present study investigated whether BBS had immunosuppressive effects on small bowel allografts.

METHODS

Allogeneic SBT was performed heterotopically in rats (n = 12) that received daily administration of 0.1 mg/kg/d TRL from postoperative day 0 to day 14. Rats divided into two groups of six rats each were administered BBS or normal saline as a control. Biopsy of the allograft was performed from the stomal site on postoperative days 6, 10, and 14. The state of the graft mucosal villi was evaluated by H & E staining and TUNEL immunohistochemistry.

RESULTS

By postoperative day 14, extensive mucosal destruction accompanied by heavy transmural cellular infiltration had developed in the control group. Lymphocytes and plasma cells infiltrated the lamina propria of the allograft without the distorting villous architecture in the BBS group. The TUNEL index of graft mucosa in the control group was 1.26% +/- 0.37% (mean +/- SD) and that in the BBS group, 0.59% +/- 0.20%, respectively (p < .001).

CONCLUSION

This study demonstrated an immunosuppressive effect of bombesin on transplanted allografts, which might dramatically reduce the dose of TRL required for postoperative immunosuppression.