Long-term outcomes of drug-induced autoimmune-like hepatitis after pulse steroid therapy.

AIM: Pulse steroid therapy occasionally causes drug-induced autoimmune-like hepatitis (DI-ALH), but the long-term outcome of treated patients is not well known. In this study, we investigated the long-term outcomes of DI-ALH due to pulse steroid therapy. METHODS: We retrospectively reviewed the medical records of 405 patients treated with pulse high-dose methylprednisolone in Kurashiki Central Hospital. The frequency and clinicopathological characteristics of acute liver injury that occurred within 3 months after the therapy were analyzed. The diagnosis of DI-ALH was made according to the revised international autoimmune hepatitis group criteria. RESULTS: Among the 405 patients treated with methylprednisolone, 61 (15.1%) had acute liver injury after the pulse steroid therapy, and DI-ALH was diagnosed in five patients (1.2%). Absence of oral prednisolone tapering after the pulse steroid therapy was a significant risk factor for the subsequent development of DI-ALH (odds ratio 11.9; p = 0.017). One patient was treated with 3 days of intravenous methylprednisolone followed by oral prednisolone. Two patients were treated with glycyrrhizin followed by oral prednisolone due to ineffectiveness of glycyrrhizin. Remission was achieved with glycyrrhizin alone, and spontaneous remission without drug therapy occurred in one patient each. During the median follow-up period of 34 months, no relapse was evident in all the patients without maintenance therapy. CONCLUSIONS: Pulse steroid therapy can cause DI-ALH, especially when subsequent prednisolone is not tapered. Prednisolone is effective for DI-ALH due to pulse steroid therapy, and can be safely withdrawn once remission is achieved.

[Antiemetic Therapy for Vomiting and Nausea Related to Hepatic Arterial Infusion Chemotherapy Using Cisplatin in Patients with Hepatocellular Carcinoma].

Combination therapy using multiple antiemetic drugs is recommended for intravenous administration of cisplatin, a highly emetogenic agent, whereas a 5-HT3 receptor antagonist alone is commonly used in hepatic arterial infusion chemotherapy using cisplatin for hepatocellular carcinoma owing to its less toxicity than that in the intravenous administration. Given that optimal antiemetic therapy is not yet established, we retrospectively investigated the efficacy of antiemetic drugs for hepatic arterial infusion chemotherapy using cisplatin. This study enrolled 72 patients with hepatocellular carcinoma who received hepatic arterial infusion chemotherapy using cisplatin at Kurashiki Central Hospital between January 2011 and May 2019. A 5-HT3 receptor antagonist was used in all cases, while aprepitant and/or dexamethasone were used concomitantly in 6 cases. After chemotherapy, a complete response rate for 5 days was achieved in 73.6% of the patients; however, complete control could be achieved only in 29.2%. During these 5 days, both rates were lower on days 2-5 than on day 1. In addition, younger age was associated with worse control rates. Our findings suggest that more effective antiemetic therapy is needed for hepatic arterial infusion chemotherapy using cisplatin, especially in non-elderly patients.

Endoscopic placement of covered versus uncovered self-expandable metal stents for palliation of malignant gastric outlet obstruction.

OBJECTIVE: Stenting is an established endoscopic therapy for malignant gastric outlet obstruction (mGOO). The choice of stent (covered vs uncovered) has been examined in prior randomised studies without clear results. DESIGN: In a multicentre randomised prospective study, we compared covered (CSEMS) with uncovered self-expandable metal stents (UCSEMS) in patients with mGOO; main outcomes were stent dysfunction and patient survival, with subgroup analyses of patients with extrinsic and intrinsic tumours. RESULTS: Overall survival was poor with no difference between groups (probability at 3 months 49.7% for covered vs 48.4% for uncovered stents; log-rank for overall survival p=0.26). Within that setting of short survival, the proportion of stent dysfunction was significantly higher for uncovered stents (35.2% vs 23.4%, p=0.01) with significantly shorter time to stent dysfunction. This was mainly relevant for patients with extrinsic tumours (stent dysfunction rates for uncovered stents 35.6% vs 17.5%, p<0.01). Subgrouping was also relevant with respect to tumour ingrowth (lower with covered stents for intrinsic tumours; 1.6% vs 27.7%, p<0.01) and stent migration (higher with covered stents for extrinsic tumours: 15.3% vs 2.5%, p<0.01). CONCLUSIONS: Due to poor patient survival, minor differences between covered and uncovered stents may be less relevant even if statistically significant; however, subgroup analysis would suggest to use covered stents for intrinsic and uncovered stents for extrinsic malignancies.

[Recurrence of malignant lymphoma immediately after treatment for hepatitis C virus using direct-acting antivirals].

A Japanese male in his 70s with chronic hepatitis C was diagnosed with diffuse large B-cell lymphoma and achieved and maintained complete remission following treatment with eight cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisolone). Seven years later, he received the direct-acting antivirals (DAAs) sofosbuvir/ledipasvir for hepatitis C virus (HCV) genotype 1b. Although the patient achieved sustained virological response immediately after the initial treatment period, laboratory data showed elevation of LD and soluble IL-2R. Computer tomography showed diffuse intraabdominal lymph node swelling and splenomegaly. Lymph node biopsy revealed the relapse of lymphoma. The lymphoma cells were resistant to chemotherapy, and the patient died five months later. Several studies reported early recurrence of hepatocellular carcinoma after HCV treatment using DAAs. However, the relationship between DAAs and hepatocellular carcinoma recurrence remains unclear. Nonetheless, possible cancer recurrence should be considered in patients with a history of lymphoma who are prescribed DAAs to treat HCV.

Outcomes of endoscopic biliary drainage in pancreatic cancer patients with an indwelling gastroduodenal stent: a multicenter cohort study in West Japan.

BACKGROUND AND AIMS: Gastroduodenal and biliary obstruction may occur synchronously or asynchronously in advanced pancreatic cancer, and endoscopic double stent placement may be required. EUS-guided biliary drainage (EUS-BD) often is performed after unsuccessful placement of an endoscopic transpapillary stent (ETS), and EUS-BD may be beneficial in double stent placement. This retrospective multicenter cohort study compared the outcomes of ETS placement and EUS-BD in patients with an indwelling gastroduodenal stent (GDS). METHODS: We recorded the clinical outcomes of patients at 5 tertiary-care medical centers who required biliary drainage after GDS placement between March 2009 and March 2014. RESULTS: Thirty-nine patients were included in this study. Patients' mean age was 68.5 years; 23 (59.0%) were men. The GDS overlay the papilla in 23 patients (59.0%). The overall technical success rate was significantly higher with EUS-BD (95.2%) than with ETS placement (56.0%; P < .01). Furthermore, the technical success rate was significantly higher with EUS-BD (93.3%) than with ETS placement (22.2%; P < .01) when the GDS overlies the papilla. The overall clinical success rate of EUS-BD also was significantly higher than for ETS placement (90.5% vs 52.0%, respectively; P = .01), and there was no significant difference in the incidence of adverse events (ETS, 32.0% vs EUS-BD, 42.9%; P = .65). CONCLUSION: Endoscopic double stent placement with EUS-BD is technically and clinically superior to ETS placement in patients with an indwelling GDS. EUS-BD should be considered the first-line treatment option for patients with an indwelling GDS that overlies the papilla. ETS placement remains a reasonable alternative when the papilla is not covered by the GDS.

Factors predicting through-the-scope gastroduodenal stenting outcomes in patients with gastric outlet obstruction: a large multicenter retrospective study in West Japan.

BACKGROUND AND AIMS: Endoscopic gastroduodenal stenting for malignant gastric outlet obstruction recently has become more effective, but the factors that predict gastroduodenal stenting outcomes are poorly defined. This multicenter retrospective cohort study evaluated the clinical outcomes of gastroduodenal stenting in malignant gastroduodenal obstruction and identified factors predicting clinical ineffectiveness, stent dysfunction, and adverse events. METHODS: All consecutive patients with malignant gastroduodenal obstruction who underwent through-the-scope gastroduodenal stenting from 2009 to 2014 at 4 tertiary-care medical centers were identified. Clinically ineffective stenting was defined as symptom recurrence and a gastric outlet obstruction scoring system (GOOSS) score <2. RESULTS: Of the 278 patients (mean age ± standard deviation [SD] 71.7 ± 11.4 years), 121 (43.5%) and 87 (31.3%) had pancreatic and gastric cancer, respectively. Technical success was achieved in 277 patients (99.6%). GOOSS scores rose from 0.5 ± 0.6 to 2.6 ± 0.8. Stenting was ineffective in 32 patients (12.6%). Stent dysfunction that caused symptom recurrence during follow-up developed in 46 patients (16.6%). Adverse events occurred in 49 patients (17.7%). Three or more stenosis sites (odds ratio [OR] = 6.11; P < .01) and Karnofsky performance scores ≤50 (OR = 6.63; P < .01) predicted clinical ineffectiveness. Karnofsky performance scores ≤50 predicted stent dysfunction (hazard ratio [HR] = 3.63; P < .01). Bile duct stenosis (HR = 9.55; P = .02) and liver metastasis (HR = 9.42; P < .01) predicted stent overgrowth. Covered stent predicted stent migration (HR = 12.63; P < .01). Deployment of 2 stents predicted perforation (HR = 854.88; P < .01). CONCLUSIONS: Through-the-scope gastroduodenal stenting tended to be ineffective in patients with poor performance status and long stenosis sites. Stent dysfunction occurred more frequently in patients with poorer performance status. Deployment of 2 stents was a risk factor for perforation. Identification of these risk variables may help yield better gastroduodenal stenting outcomes.

Comparison of combined transcatheter arterial chemoembolization and radiofrequency ablation with surgical resection by using propensity score matching in patients with hepatocellular carcinoma within Milan criteria.

PURPOSE: To retrospectively compare the outcome of combined transcatheter arterial chemoembolization (TACE) and radiofrequency ablation (RFA) (hereafter, TACE-RFA) with that of surgical resection (SR) in patients with hepatocellular carcinoma (HCC) within the Milan criteria. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. From January 2000 to December 2010, 154 patients (mean age, 69.9 years; age range, 50-89 years; 107 men, 47 women) underwent TACE-RFA, and 176 patients (mean age, 66.9 years; age range, 29-83 years; 128 men, 48 women) underwent SR. Patients with HCC who underwent TACE-RFA or SR were enrolled if they met the following inclusion criteria: no previous HCC treatment, one HCC lesion no larger than 5 cm or up to three nodules smaller than 3 cm without vascular invasion or extrahepatic metastasis, and Child-Pugh class A or B disease. Cumulative overall survival (OS) and disease-free survival (DFS) rates were compared after adjustment with propensity score matching. RESULTS: After this adjustment, OS rates were comparable between the groups (P = .393), but DFS was superior in the SR group (P < .048). Among patients with very early stage HCC (lesions <2 cm in diameter), OS and DFS rates in the SR group were significantly higher than those in the TACE-RFA group (P < .001 and P = .008, respectively). However, adjustment with propensity score matching yielded comparable OS and DFS rates between the two groups (P = .348 and P = .614, respectively). CONCLUSION: TACE-RFA may be a viable alternative treatment for early-stage HCC when SR is not feasible.

Corticosteroid-refractory autoimmune hepatitis after COVID-19 vaccination: a case report and literature review.

Several vaccines have been developed for coronavirus disease 2019 (COVID-19) and are used worldwide. Here we report a case of severe acute hepatitis induced by COVID-19 vaccination. A 54-year-old woman received two doses of the Pfizer-BioNTech COVID-19 mRNA vaccine and an additional dose of the Moderna COVID-19 mRNA vaccine. Seven days after the third dose, she noticed fatigue, appetite loss and dark urine. Laboratory tests were consistent with severe liver injury and jaundice. Anti-smooth muscle antibody and HLA-DR4 were positive; thus, we suspected that she had autoimmune hepatitis (AIH). Intravenous methylprednisolone followed by oral prednisolone were administered. Because remission was not achieved, we performed percutaneous liver biopsy. Histologically, pan-lobular inflammation with moderate infiltration of lymphocytes and macrophages, interface hepatitis, and rosette formation were present. We regarded these findings as confirmation of the diagnosis of AIH. As she had not responded to corticosteroids, we added azathioprine. Liver biochemistry tests gradually improved, and prednisolone could be tapered without relapse of AIH. Dozens of cases of AIH after COVID-19 vaccination have been reported. Corticosteroids were effective in most cases, but some patients have died from liver failure after vaccination. This case illustrates the efficacy of azathioprine for steroid-refractory AIH induced by COVID-19 vaccination.

Real-world efficacy of antibiotic prophylaxis for upper gastrointestinal bleeding in cirrhotic patients in Japan.

BACKGROUND AND AIMS: Antibiotic prophylaxis is recommended for cirrhotic patients with upper gastrointestinal bleeding (UGIB). However, the frequency of bacterial infection in such patients has remarkably decreased over the decades, which has reduced the necessity for prophylaxis. Therefore, here we investigated the real-world adherence and effectiveness of antibiotic prophylaxis in cirrhotic patients with UGIB in Japan. METHODS: This population-based study was conducted with a Japanese real-world database of the Health, Clinic, and Education Information Evaluation Institute. We enrolled cirrhotic patients who were hospitalized for UGIB between April 2010 and March 2020. After those who died within 24 h and who had aspiration pneumonia at admission were excluded, 1232 patients were analyzed. Rates of 6-week mortality, in-hospital bacterial infection, 30-day readmission, and length of hospital stay were evaluated. RESULTS: Prophylactic antibiotics were prescribed in 142 (11.5%) patients. Multivariate analysis revealed that antibiotic prophylaxis was not significantly associated with either 6-week mortality or bacterial infection. After propensity score matching, the rates of 6-week mortality (7.2% vs. 8.4%, P = 0.810), bacterial infection (9.6% vs. 4.2%, P = 0.082), and 30-day unexpected readmission (7.2% vs. 7.8%, P = 1.000) were similar in patients with and without prophylaxis, whereas the median length of hospital stay was significantly longer in patients with prophylaxis (17 days vs. 13 days, P = 0.013). CONCLUSIONS: Under current real-world circumstances in Japan, prophylactic antibiotics were prescribed in only 11.5% of cirrhotic patients with UGIB and were not associated with better clinical outcomes.

Mycophenolate mofetil for immune checkpoint inhibitor-related hepatotoxicity relapsing during dose reduction of corticosteroid: A report of two cases and literature review.

BACKGROUND: Immune checkpoint inhibitors (ICIs) sometimes cause immune-related liver injury, which can lead to cessation of treatment, hospitalization, and even mortality. Although high-dose corticosteroids are usually effective in treatment of ICI-related liver injury, one fifth of affected patients require additional immunosuppressive therapy. It remains uncertain how best to treat ICI-related liver injury that relapses under corticosteroid therapy after temporary remission. CASE: Here we report two cases of ICI-related liver injury successfully treated with mycophenolate mofetil (MMF). In the first case, a 74-year-old man with stage IIIA lung cancer underwent curative chemoradiotherapy. After the second infusion of durvalumab, grade 3 ICI-related liver injury (mixed pattern) developed. In the second case, a 46-year-old man with stage IVB lung cancer received pembrolizumab-containing chemotherapy. After the first cycle, grade 2 ICI-related hepatitis developed. In the both cases, liver injury improved with high-dose prednisolone but relapsed during tapering of the drug. After liver biopsy was performed to confirm the diagnosis of ICI-related liver injury, MMF (2000 mg/day) was added. MMF was effective for both patients and permitted discontinuation or reduction of prednisolone. CONCLUSION: MMF appears to be an appropriate treatment option for ICI-related liver injury that respond to high-dose corticosteroids but relapse during steroid tapering.

[A case of erythropoietic protoporphyria with severe liver dysfunction].

A 27-year-old man was admitted to our hospital for evaluation and treatment of liver dysfunction with jaundice and hepatosplenomegaly. The patient had severe photosensitivity from childhood. Upper gastrointestinal endoscopy revealed mild esophageal varices. The clinical manifestations, analyses of the urine and blood for porphyrins and skin biopsy led us to a diagnosis of erythropoietic protoporphyria. Because of acute deterioration of liver function, living donor liver transplantation was performed. The resected liver revealed cirrhosis. We report a rare case of erythropoietic protoporphyria with severe liver dysfunction and present a review of the literature.

Stereotactic body radiation therapy versus radiofrequency ablation for single small hepatocellular carcinoma: a propensity-score matching analysis of their impact on liver function and clinical outcomes.

BACKGROUND: Stereotactic body radiation therapy (SBRT) has high efficacy for early-stage hepatocellular carcinoma (HCC) and is an accepted alternative to radiofrequency ablation (RFA). However, SBRT for HCC may cause subacute liver injury leading to negative clinical outcomes. In this study, we compared changes of liver function and prognosis after SBRT or RFA in patients with single, small HCC by using a propensity-score matching analysis. METHODS: We reviewed medical records of 140 patients with single ≤3 cm HCC treated with SBRT or RFA at Kurashiki Central Hospital between January 2014 and February 2019. Changes of albumin-bilirubin (ALBI) score, local recurrence, and overall survival were compared between the propensity-score matched groups (31 patients treated with SBRT and 62 treated with RFA). RESULTS: The ALBI score increased modestly but significantly after SBRT, while it was unchanged in the RFA group; the intergroup difference was statistically significant (P=0.004). No local recurrence was identified in the SBRT group, whereas the cumulative recurrence incidence was 9.7% in the RFA group (P=0.023). Overall survival was not significantly different between the two groups (hazard ratio: 1.32, 95% confidence interval: 0.60-2.89, P=0.401). CONCLUSIONS: SBRT had modestly negative impact on liver function but with appraisable local control of HCC. Our findings should contribute to the selection of this modality for treatment of single, small HCC.

Universal antibiotic prophylaxis may no longer be necessary for patients with acute variceal bleeding: A retrospective observational study.

A few decades ago, antibiotic prophylaxis for patients with acute variceal bleeding was reported beneficial. However, endoscopic and systemic therapy for variceal bleeding has dramatically improved since then, so the necessity of prophylactic antibiotics can be questioned. In this study, we reevaluated the efficacy of antibiotic prophylaxis in acute variceal bleeding, using the most recent data in our hospital.We retrospectively analyzed the medical records of 150 patients with acute variceal bleeding who were admitted to Kurashiki Central Hospital between January 2012 and December 2016. We compared the rates of bacterial infection, in-hospital mortality, 5-day rebleeding rate, and 30-day emergency readmission between patients treated or not treated with antibiotic prophylaxis.Forty-six patients (30.7%) received antibiotic prophylaxis; 104 (69.3%) did not. The rates of the outcomes in patients with antibiotic prophylaxis were 6.5% (bacterial infection), 4.3% (in-hospital mortality), 2.2% (5-day rebleeding), and 10.9% (30-day emergency readmission) and were not significantly different form the corresponding figures in those without antibiotic prophylaxis (1.9%, 7.7%, 1.9%, and 10.6%, respectively). Moreover, these rates in our patients, even without antibiotic prophylaxis, were much lower than rates reported in past years, perhaps because of improvements in care of patients with variceal hemorrhage.Antibiotic prophylaxis was not associated with significantly better outcomes of bacterial infection, mortality, rebleeding or readmission rate in patients with acute variceal bleeding. Universal antibiotic prophylaxis for patients with acute variceal bleeding should be reconsidered.

[A case of ruptured giant liver cyst complicated by Candida infection].

A 75-year-old woman who had been given a diagnosis of a giant liver cyst occupying the right hepatic lobe was admitted to our hospital complaining of abdominal pain. CT examination revealed the size of cyst was smaller than before and the level of CRP was elevated, suggesting the development of peritonitis due to rupture of the cyst. As Candida albicans was detected from both ascites and the cyst, we treated her with continuous percutaneous transhepatic drainage and antimycotic agents. The cyst markedly diminished, and she became free of infection and peritonitis, suggesting drainage was exceedingly effective.

Mucin-producing hepatocellular carcinoma without morphological features of biliary differentiation: A case report.

RATIONALE: Hepatocellular carcinoma has been believed not to produce mucin unless it has biliary differentiation. However, some cases of hepatocellular carcinoma with extracellular myxoid change have been reported recently, raising the possibility that, in rare cases, hepatocellular carcinoma cells produce mucin. PATIENT CONCERNS: Here we report a case of hepatocellular carcinoma that contained intracellular and extracellular myxoid matrix without morphological evidence of biliary differentiation, although cells in a portion of the tumor were positive for the epithelial markers cytokeratin 7 and 19. She was brought to our hospital due to abnormal liver tests and a large liver tumor found by ultrasound examination. DIAGNOSES: The liver tumor showed typical imaging findings of hepatocellular carcinoma. INTERVENTIONS: The tumor was resected with negative margins, and pathologically diagnosed as hepatocellular carcinoma with mucin production. OUTCOMES: The patient has been free from recurrence of cancer during two-years' follow-up. LESSONS: Our case suggests that hepatocellular carcinoma cells can produce mucin without or before morphological differentiation to biliary phenotypes, an observation that may help elucidate the mechanism for the development of combined hepatocellular and cholangiocarcinoma.

STAT3 is constitutively activated and supports cell survival in association with survivin expression in gastric cancer cells.

Signal transduction and activator of transcription 3(STAT3) signaling is constitutively activated in various tumors, and is involved in cell survival and proliferation during oncogenesis. There are few reports, however, on the role of STAT3 signaling in gastric cancer. The aim of the present study was to clarify the role of STAT3 signaling in apoptosis and cellular proliferation in gastric cancer. Here we reported that STAT3 was constitutively activated in various human gastric cancer cells and its inhibition by ectopic dominant-negative STAT3 or Janus kinase inhibitor, tyrphostin AG490, induced apoptosis. Furthermore, STAT3 inhibition markedly decreased survivin expression, and forced expression of survivin rescued AGS cells from apoptosis induced by STAT3 inhibition. Although some reports demonstrated that the PI3K/Akt pathway regulates survivin expression, inhibition of the PI3K/Akt pathway did not affect survivin expression in AGS and MKN1 cells. Finally, activated form of STAT3, Tyr-705 phospho-stat3, was found in the nucleus of cancer cells in 11 of 40 (27.5%) human gastric cancer specimens. These findings suggest that constitutively activated STAT3 signaling supports gastric cancer cell survival in association with survivin expression.2004

Candidate markers for stem and early progenitor cells, Musashi-1 and Hes1, are expressed in crypt base columnar cells of mouse small intestine.

Musashi-1, a neural RNA-binding protein, is important for maintaining neural stem cells. Both Musashi-1 and Hes1, a transcriptional factor regulated by Musashi-1, are expressed in the small intestine. Here we show that Musashi-1 is present in a few epithelial cells just above the Paneth cells in the small intestinal crypt, the putative position of stem cells, whereas Hes1 is expressed in lower crypt cells just above the Paneth cells, including Musashi-1-positive cells. Musashi-1 and Hes1 were not expressed in Paneth cells. Notably, Musashi-1 and Hes1 were coexpressed in the crypt base columnar cells located between the Paneth cells. These findings suggest that not only the cells just above Paneth cells but also the crypt base columnar cells between the Paneth cells have stem cell characteristics.

Conversion from latent to symptomatic Sheehan's syndrome by pegylated interferon therapy for chronic hepatitis C.

A 58-year-old woman with chronic hepatitis C was admitted to our hospital to receive interferon (IFN) therapy. Twenty years earlier she had received blood transfusion because of obstetric hemorrhage. Blood test showed mild hypothyroidism and a relatively elevated eosinophil count. Therapy with pegylated IFNalpha-2a was started, and two days later she complained of nausea and severe malaise. Blood test showed hyponatremia, and plasma prolactin, growth hormone and cortisol levels were all decreased. A simultaneous administration test of lutenizing hormone releasing-, corticotrophin releasing-, growth hormone releasing- and thyrotropin releasing-hormones revealed that only adrenocorticotropic hormone was responsive. Magnetic resonance imaging showed atrophy of anterior lobe of pituitary gland. We diagnosed that IFN therapy disclosed latent Sheehan's syndrome due to previous obstetric hemorrhage. Following supplementation of thyroid and adrenal cortical hormones, we were able to complete IFN therapy. Thus, before IFN therapy for woman patients it is important to suspect latent Sheehan's syndrome when the patient had a history of obstetric hemorrhage.

Hes1-deficient mice show precocious differentiation of Paneth cells in the small intestine.

We have previously shown that Hes1 is expressed both in putative epithelial stem cells just above Paneth cells and in the crypt base columnar cells between Paneth cells, while Hes1 is completely absent in Paneth cells. This study was undertaken to clarify the role of Hes1 in Paneth cell differentiation, using Hes1-knockout (KO) newborn (P0) mice. Electron microscopy revealed premature appearance of distinct cells containing cytoplasmic granules in the intervillous region in Hes1-KO P0 mice, whereas those cells were absent in wild-type (WT) P0 mice. In Hes1-KO P0 mice, the gene expressions of cryptdins, exclusively present in Paneth cells, were all enhanced compared with WT P0 mice. Immunohistochemistry demonstrated increased number of both lysozyme-positive and cryptdin-4-positive cells in the small intestinal epithelium of Hes1-KO P0 mice as compared to WT P0 mice. Thus, Hes1 appears to have an inhibitory role in Paneth cell differentiation in the small intestine.

Growth promoting effect of thioredoxin on intestinal epithelial cells.

Paneth cells are located at the bases of intestinal crypts, and their cytoplasmic granules contain large amounts of zinc. We previously showed that administration of diphenylthiocarbazone (dithizone), a zinc chelater, to rats induced the selective death of Paneth cells. This was followed by a transient wave of epithelial cell proliferation in the entire crypts. In the study described here, we again applied this experimental model in an attempt to identify novel growth-promoting factors in the small intestine. Male Wistar rats were injected with dithizone and killed 6 hr later. Messenger RNAs (mRNAs) were extracted from the terminal ileum for the construction of a cDNA library. This library was then transfected into the human intestinal cell line Caco-2, and the cells that continued to grow in the medium containing only 1% FBS were cloned. One of the cDNA sequences identified from those transfection experiments was the full-length rat thioredoxin (TRX) gene. To confirm the growth-promoting effect of this cDNA, we transfected it into Caco-2 cells again. These clones proliferated in the medium containing only 1% FBS, while the control clones failed to show any growth. Transient oxidative stress exerted by the addition of oxidative reagents diamide and hydrogen peroxide partially suppressed the growth of TRX-transfected cells. Northern hybridization analysis revealed that TRX expression in rat ileum after dithizone treatment was altered in accordance with intestinal epithelial regeneration in the crypts. Single-cell RT-PCR also showed TRX mRNA expression in Paneth cells. These studies identify rat thioredoxin as a growth-promoting factor for intestinal epithelial cells.