Impact of gallbladder hypoplasia on hilar hepatic ducts in biliary atresia.

BACKGROUND: Biliary atresia (BA) is an intractable disease of unknown cause that develops in the neonatal period. It causes jaundice and liver damage due to the destruction of extrahepatic biliary tracts,. We have found that heterozygous knockout mice of the SRY related HMG-box 17 (Sox17) gene, a master regulator of stem/progenitor cells in the gallbladder wall, exhibit a condition like BA. However, the precise contribution of hypoplastic gallbladder wall to the pathogenesis of hepatobiliary disease in Sox17 heterozygous embryos and human BA remains unclear. METHODS: We employed cholangiography and histological analyses in the mouse BA model. Furthermore, we conducted a retrospective analysis of human BA. RESULTS: We show that gallbladder wall hypoplasia causes abnormal multiple connections between the hilar hepatic bile ducts and the gallbladder-cystic duct in Sox17 heterozygous embryos. These multiple hilar extrahepatic ducts fuse with the developing intrahepatic duct walls and pull them out of the liver parenchyma, resulting in abnormal intrahepatic duct network and severe cholestasis. In human BA with gallbladder wall hypoplasia (i.e., abnormally reduced expression of SOX17), we also identify a strong association between reduced gallbladder width (a morphometric parameter indicating gallbladder wall hypoplasia) and severe liver injury at the time of the Kasai surgery, like the Sox17-mutant mouse model. CONCLUSIONS: Together with the close correlation between gallbladder wall hypoplasia and liver damage in both mouse and human cases, these findings provide an insight into the critical role of SOX17-positive gallbladder walls in establishing functional bile duct networks in the hepatic hilus of neonates.

Biliary atresia (BA) is a disease in newborns that causes a serious liver condition due to damage to the bile ducts (the pathways that carry bile juice). Although reduced function of a key gene called Sox17, which is essential for forming the gallbladder wall, has been observed in some BA cases, the link between gallbladder issues and liver damage is unknown. This study has shown how damage spreads through the bile ducts in the liver around the time of birth when there are problems in the gallbladder wall due to reduced SOX17 function. The findings indicate that proper growth of the gallbladder wall during this critical period is essential for forming a normal network of bile ducts in the developing liver. This discovery is promising for early diagnosis and better treatment of BA in newborns.

Endoplasmic reticulum transporter OAT2 regulates drug metabolism and interaction.

Xenobiotic metabolic reactions in the hepatocyte endoplasmic reticulum (ER) including UDP-glucuronosyltransferase and carboxylesterase play central roles in the detoxification of medical agents with small- and medium-sized molecules. Although the catalytic sites of these enzymes exist inside of ER, the molecular mechanism for membrane permeation in the ER remains enigmatic. Here, we investigated that organic anion transporter 2 (OAT2) regulates the detoxification reactions of xenobiotic agents including anti-cancer capecitabine and antiviral zidovudine, via the permeation process across the ER membrane in the liver. Pharmacokinetic studies in patients with colorectal cancer revealed that the half-lives of capecitabine in rs2270860 (1324C > T) variants was 1.4 times higher than that in the C/C variants. Moreover, the hydrolysis of capecitabine to 5'-deoxy-5-fluorocytidine in primary cultured human hepatocytes was reduced by OAT2 inhibitor ketoprofen, whereas capecitabine hydrolysis directly assessed in human liver microsomes were not affected. The immunostaining of OAT2 was merged with ER marker calnexin in human liver periportal zone. These results suggested that OAT2 is involved in distribution of capecitabine into ER. Furthermore, we clarified that OAT2 plays an essential role in drug-drug interactions between zidovudine and valproic acid, leading to the alteration in zidovudine exposure to the body. Our findings contribute to mechanistically understanding medical agent detoxification, shedding light on the ER membrane permeation process as xenobiotic metabolic machinery to improve chemical changes in hydrophilic compounds.

Osteoid osteoma appearing after bony fracture in a girl with osteogenesis imperfecta.

Osteoid osteoma (OO) is a common, benign bone tumor. However, there are no case reports of OO associated with osteogenesis imperfecta (OI), or pathological fractures in OO. A 3-year-old girl with OI sustained a complete right tibial diaphyseal fracture. Bony fusion was completed after 4 months of conservative therapy; nevertheless, 18 months later spontaneous pain appeared at the fracture site, without any cause. Plain radiographs showed a newly apparent, rounded area of translucency 1 cm in diameter, just overlapping the previous fracture. Images obtained using three-dimensional time-resolved contrast-enhanced magnetic resonance angiography showed strong central enhancement in the early phase, with an apparent nidus, suggesting the diagnosis of OO. Nineteen months after the first fracture, while skipping, the patient refractured her tibial diaphysis at the site of the previous fracture. This is a very rare case of OO, apparently co-existing with OI and leading to a bony fracture. In our case, the combination of bone fragility in OI and a recent fracture at the site of the OO may have caused the re-fracture.

Living-donor liver transplantation for methylmalonic acidemia patient with hepatocellular carcinoma: A case report and literature review.

BACKGROUND: Methylmalonic acidemia (MMA) is an autosomal recessive disorder caused by defects in propionyl-CoA (P-CoA) catabolism; of note, liver neoplasms rarely occur as a long-term complication of the disorder. Herein, we report the case of a patient with MMA and hepatocellular carcinoma (HCC) who was successfully treated with a living-donor liver transplant (LDLT) following prior kidney transplantation. CASE REPORT: A 25-year-old male patient with MMA underwent LDLT with a left lobe graft because of metabolic instability and liver neoplasms. He had presented with chronic symptoms of MMA, which had been diagnosed by genetic testing. Additionally, he had undergone living-donor kidney transplantation with his father as the donor due to end-stage kidney disease 6 years before the LDLT. He had an episode of metabolic decompensation triggered by coronavirus disease in 2019. Imaging studies revealed an intrahepatic neoplasm in the right hepatic lobe. Due to concerns about metabolic decompensation after hepatectomy, LDLT was performed using a left lobe graft obtained from the patient's mother. Pathological findings were consistent with the characteristics of well-to-moderately differentiated HCC. The postoperative course was uneventful, and the patient was discharged 48 days after the LDLT without any complications. At the 9-month follow-up, the patient's condition was satisfactory, with sufficient liver graft function and without metabolic decompensation. CONCLUSION: This case indicates that although HCC is a rare complication in patients with MMA, clinicians should be aware of hepatic malignancies during long-term follow-up.

Historical Cohort Study of Congenital Isolated Hypoganglionosis of the Intestine: Determining the Best Surgical Interventions.

No standard diagnostic method or surgical treatment for congenital isolated hypoganglionosis (CIHG) has been established. This study aimed to analyze the clinical outcomes of patients with CIHG and identify the best surgical interventions provided thus far. Data on surgical interventions in 19 patients were collected between 1992 and 2020, including the type of enterostomy, type of revision, and length of the intestines. Ganglion cells in the myenteric plexus were enumerated using Hu C/D staining. The ratio of the length of the small intestine to its height was defined as the intestinal ratio (IR). The outcomes were assessed using the stoma output, growth parameters including the body mass index (BMI), and parenteral nutrition (PN) dependency. All patients required a diverting enterostomy. The IR ranged from 0.51 to 1.75 after multiple non-transplant surgeries. The stoma types were tube-stoma, end-stoma, Santulli-type, and Bishop-Koop (BK)-type. Patients with Santulli- or BK-type stomas had better BMIs and less PN dependency in terms of volume than those with end-stomas or tube-stomas. Two patients with BK-type stomas were off PN, and three who underwent an intestinal transplantation (Itx) achieved enteral autonomy. The management of CIHG involves a precise diagnosis using Hu C/D staining, neonatal enterostomy, and stoma revision using the adjusted IR and Itx if other treatments do not enable enteral autonomy.

Prevalence of pathogenic variants in cancer-predisposing genes in second cancer after childhood solid cancers.

BACKGROUND: Second malignant neoplasms (SMNs) are one of the most severe late complications after pediatric cancer treatment. However, the effect of genetic variation on SMNs remains unclear. In this study, we revealed germline genetic factors that contribute to the development of SMNs after treatment of pediatric solid tumors. METHODS: We performed whole-exome sequencing in 14 pediatric patients with SMNs, including three brain tumors. RESULTS: Our analysis revealed that five of 14 (35.7%) patients had pathogenic germline variants in cancer-predisposing genes (CPGs), which was significantly higher than in the control cohort (p < 0.01). The identified genes with variants were TP53 (n = 2), DICER1 (n = 1), PMS2 (n = 1), and PTCH1 (n = 1). In terms of the type of subsequent cancer, leukemia and multiple episodes of SMN had an exceptionally high rate of CPG pathogenic variants. None of the patients with germline variants had a family history of SMN development. Mutational signature analysis showed that platinum drugs contributed to the development of SMN in three cases, which suggests the role of platinum agents in SMN development. CONCLUSIONS: We highlight that overlapping effects of genetic background and primary cancer treatment contribute to the development of second cancers after treatment of pediatric solid tumors. A comprehensive analysis of germline and tumor samples may be useful to predict the risk of secondary cancers.

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 .

Minimal residual disease detection by mutation-specific droplet digital PCR for leukemia/lymphoma.

Minimal residual disease (MRD) is usually defined as the small number of cancer cells that remain in the body after treatment. The clinical significance of MRD kinetics is well recognized in treatment of hematologic malignancies, particularly acute lymphoblastic leukemia (ALL). Real time quantitative PCR targeting immunoglobulin (Ig) or T-cell receptor (TCR) rearrangement (PCR-MRD), as well as multiparametric flow cytometric analysis targeting antigen expression, are widely used in MRD detection. In this study, we devised an alternative method to detect MRD using droplet digital PCR (ddPCR), targeting somatic single nucleotide variants (SNVs). This ddPCR-based method (ddPCR-MRD) had sensitivity up to 1E-4. We assessed ddPCR-MRD at 26 time points from eight T-ALL patients, and compared it to the results of PCR-MRD. Almost all results were concordant between the two methods, but ddPCR-MRD detected micro-residual disease that was missed by PCR-MRD in one patient. We also measured MRD in stored ovarian tissue of four pediatric cancer patients, and detected 1E-2 of submicroscopic infiltration. Considering the universality of ddPCR-MRD, the methods can be used as a complement for not only ALL, but also other malignant diseases regardless of tumor-specific Ig/TCR or surface antigen patterns.

"Another inchworm sign" on dynamic contrast-enhanced magnetic resonance imaging in pediatric patients with cystitis cystica and glandularis: Radiologic-pathologic correlation.

Cystitis cystica and glandularis is a hyperproliferative disease of the urothelium, and may form a papillary or polypoid mass. Clinically, these mass lesions are often difficult to distinguish from malignant tumors. We present a pediatric patient of cystitis cystica and glandularis with a bladder mass and discuss dynamic contrast-enhanced magnetic resonance imaging (MRI) findings and histopathological profiles, which have not been previously explored in the literature. Dynamic contrast-enhanced MRI showed unique, superficial, strong enhancement that resembles an inchworm in appearance. The term "inchworm sign" is a characteristic finding on diffusion-weighted MRI, proposed as a criterion for T-staging in non-muscle-invasive bladder cancer. We would like to propose another "inchworm sign" on dynamic contrast-enhanced MRI as a new hallmark of cystitis cystica and glandularis, which may differentiate it from a malignant tumor.

STAT6 gain-of-function variant exacerbates multiple allergic symptoms.

BACKGROUND: Allergic diseases were long considered to be complex multifactorial disorders. However, recent findings indicate that severe allergic inflammation can be caused by monogenic immune defects. OBJECTIVES: We sought to clarify the molecular pathogenesis of a patient with early-onset multiple allergic diseases, a high serum IgE level, hypereosinophilia, treatment-resistant severe atopic dermatitis with increased dermal collagen fiber deposition, and eosinophilic gastrointestinal disorder with numerous polypoid nodules. METHODS: A missense variant in STAT6 was identified, and its function was examined using peripheral blood, transfected HEK293 cells, lymphoblastoid cell lines, and knock-in mice with the corresponding mutation. RESULTS: Whole-exome sequencing identified a de novo heterozygous missense variant in signal transducer and activator of transcription 6 (STAT6) (p.Asp419Asn). Luciferase reporter assay revealed that the transcriptional activity of this STAT6 mutant was upregulated even without IL-4 stimulation. Phosphorylation of STAT6 was not observed in either the patient's TH2 cells or lymphoblastoid cell lines without stimulation, whereas it was induced more strongly in both by IL-4 stimulation compared with healthy controls. STAT6 protein was present in the nuclear fraction of the lymphoblastoid cell lines of the patient even in the absence of IL-4 stimulation. The patient's gastric mucosa showed upregulation of STAT6-, fibrosis-, and germinal center formation-related molecules. Some of the knock-in mice with the corresponding mutation spontaneously developed dermatitis with skin thickening and eosinophil infiltration. Moreover, serum IgE levels and mRNA expression of type 2 cytokines were increased in the knock-in mice-with or without development of spontaneous dermatitis-compared with the wild-type mice. CONCLUSIONS: A novel STAT6 gain-of-function variant is a potential cause of primary atopic disorders.

Strategy for hepatoblastoma with major vascular involvement: A guide for surgical decision-making.

BACKGROUND: Surgical management of tumor thrombus extending to the major vascular system for children with hepatoblastoma is challenging and insufficiently discussed. METHODS: We conducted a retrospective review of hepatoblastoma with tumor thrombus extending to the major vascular system (inferior vena cava, 3 hepatic veins, and portal vein trunk) treated at our center between May 2010 and June 2021. We describe our preoperative assessment, surgical strategies, and outcomes. RESULTS: We identified 9 patients (median age at the diagnosis: 3.4 years). All patients received chemotherapy before liver surgery. At the time of the diagnosis, tumor thrombus extended to the portal vein trunk (n = 6), inferior vena cava (n = 3), and 3 hepatic veins (n = 2). Among the 9 patients, 4 underwent liver resection. Liver transplantation was performed in 5 patients. The inferior vena cava wall was circumferentially resected for tumor removal in 1 patient and partially resected in 2 patients. One patient underwent liver transplantation using veno-venous bypass. Patients with tumor thrombus extending to the portal vein trunk were more likely to be managed by liver transplantation in comparison to those with tumor thrombus spreading to the inferior vena cava. The median follow-up period was 5.5 years. One patient underwent transhepatic balloon dilatation for biliary stricture after liver resection. Tumor recurrence was seen in 3 patients (33.3%; lung, n = 2; lymph node and liver, n = 1). No patients died during the follow-up period. CONCLUSION: Surgical intervention for pediatric hepatoblastoma with tumor thrombus extending into the major vascular system is safe, feasible, and achieves excellent outcomes.

Monogenic inflammatory bowel disease with STXBP2 mutations is not resolved by hematopoietic stem cell transplantation but can be alleviated via immunosuppressive drug therapy.

STXBP2, encoding syntaxin-binding protein 2, is involved in intracellular organelle trafficking and is associated with familial hemophagocytic lymphohistiocytosis type 5. Although STXBP2 mutations reportedly cause monogenic inflammatory bowel disease, the clinical course and underlying pathogenic mechanisms remain unclear. We identified a novel mutation in STXBP2 [c.1197delC, p.Ala400fs] in a boy with congenital intractable diarrhea and hemophagocytic lymphohistiocytosis (HLH). HLH was treated with intravenous prednisolone, cyclosporine, and dexamethasone palmitate. Hematopoietic stem cell transplantation (HSCT) along with prophylaxis for graft-versus-host-disease was performed at 5 months of age. Additionally, colonoscopies done before and after HSCT showed mild colitis with cryptitis. The patient showed elevated fecal calprotectin levels and persistent diarrhea even after HSCT and required partial parenteral nutrition. While anti-inflammatory treatment reduced diarrhea, it was not completely normalized even after HSCT, suggesting that the pathogenesis of inflammatory bowel disease associated with STXBP2 mutations involves both hyperinflammation and functional epithelial barrier defects.

Tolerability and safety of a new elimination diet for pediatric eosinophilic gastritis and duodenitis.

BACKGROUND: Non-esophageal eosinophilic gastrointestinal disorders (non-EoE EGIDs) are chronic inflammatory disorders with massive infiltration of eosinophils into the gastrointestinal tract. Food elimination diets are potentially effective treatments. But the existing dietary therapies have various weak points. We developed a new regimen to compensate for the shortcomings of the elemental diet and 6-food elimination diet. The new regimen consists of an amino-acid-based formula, potatoes, vegetables, fruits and restricted seasonings. We named it the "Rainbow Elimination Diet (ED)." The aims of this study were to evaluate the tolerability and safety of this diet. METHODS: A retrospective medical record examination was conducted at the National Center for Child Health and Development covering the period from January 2010 through December 2018. The medical records of patients (age 2-17 y) with histologically diagnosed non-EoE EGIDs were reviewed. The tolerability, nutritional intake, symptoms, and blood test findings were evaluated. RESULTS: Nineteen patients were offered several kinds of food-elimination diets. Seven patients (eosinophilic gastritis: 5; gastroenteritis: 1; duodenitis: 1) were treated with Rainbow ED. Six patients were compliant with this diet. The median duration of the diet induction phase was 15 days (range 14-30). All 5 patients who had had symptoms just before the induction phase became symptom-free. The body weight decreased in 5 patients (median -0.6 kg), probably because the serum protein increased, resulting in reduced edema. All 5 patients with hypoproteinemia had elevated serum albumin (median 2.9-3.5 g/dL). The ingested nutritional elements were calculated, and most of them were sufficient, except for fat and selenium. CONCLUSIONS: The Rainbow ED was well-tolerated and safe for pediatric non-EoE EGIDs.

Infantile Kaposiform hemangioendothelioma in a female patient complicated with severe obstructed jaundice: a case report.

BACKGROUND: Kaposiform hemangioendothelioma (KHE) is a rare locally aggressive vascular neoplasm that occurs mainly in the pediatric population. KHE usually originates just underneath the skin and affects deeper tissues through infiltrative growth; however, visceral tissue involvement is quite rare. CASE PRESENTATION: An 8-month-old girl with jaundice and acholic stool was referred to our hospital for further evaluation of a hepatoduodenal ligament tumor. A blood examination revealed high bilirubin and liver enzyme levels, but no signs of coagulopathy. The first attempt at a diagnostic surgical procedure did not provide sufficient diagnostic information. However, the histopathological diagnosis of the cystic duct excised in the second surgery indicated KHE. Therefore, in our case, KHE was considered a cause of obstructive jaundice. Sirolimus (rapamycin) was initiated, and the patient was discharged 7 months after admission. CONCLUSIONS: In cases of atypical hypervascular lesions in the abdominal cavity, especially in the pediatric population, it is important to consider the possibility of KHE, and surgical intervention with proper strategies is required for diagnosis, followed sequentially by promising treatments.

Relationships Between Histopathological Findings in the Liver and Prognosis in Patients With Biliary Atresia.

Background: Biliary atresia (BA) is a progressive obstructive hepatic disease that requires early diagnosis and the prompt initiation of treatment. Although portoenterostomy (PES) is usually performed as the initial surgical procedure, the liver damage may subsequently progress, such that liver transplantation (LTx) may be required. In this study, we comprehensively evaluated the histopathology of liver samples collected during PES and retrospectively evaluated its relationship with prognosis. Methods: Forty-seven patients with BA who underwent PES between 2002 and 2021 were included. Their biopsy samples were semi-quantitatively graded according to the severity of liver fibrosis, bile duct proliferation, cholestasis, ductal plate malformation, and inflammatory cell infiltration; and the expression of cluster of differentiation (CD)3, CD20, human leukocyte antigen II-DR, and α-smooth muscle actin (α-SMA). The relationships of each with the prevalence of survival with native liver (SNL) were evaluated to identify prognostic markers. Results: The median postoperative duration of follow-up was 11.8 years (maximum, 18.0 years; minimum, 3.5 years). There were no deaths during this period, but LTx was performed in 31 patients and the final prevalence of SNL was 34.0% (16/47). There were negative correlations of liver fibrosis and α-SMA with SNL, and a positive correlation between CD20 and SNL. Multivariate analysis using a proportional hazards regression model showed that only CD20 expression was significant. Conclusions: Comprehensive histopathological analysis of liver biopsy samples obtained at the time of PES showed a positive correlation between CD20 expression and SNL, suggesting that this may represent a useful prognostic marker. Level of evidence: III.