Biomedical subjects

K Chijiiwa

Publications and source records attributed to K Chijiiwa.

At least 19 recordsLinked to original sources

PubMed2006

Enhanced expression of hepatocyte growth factor activator inhibitor type 2-related small peptide at the invasive front of colon cancers.

BACKGROUND: Hepatocyte growth factor activator inhibitor type 2-related small peptide (H2RSP) is a small nuclear protein abundantly expressed in the gastrointestinal epithelium. However, its functions remain unknown. AIMS: To investigate the expression and localisation of H2RSP in normal, injured and neoplastic human intestinal tissue. METHODS: Immunohistochemical examination and in situ hybridisation for H2RSP were performed using normal and diseased intestinal specimens. Its subcellular localisation and effects on the cellular proliferation and invasiveness were examined using cultured cells. RESULTS: In the normal intestine, H2RSP was observed in the nuclei of surface epithelial cells and this nuclear localisation was impaired in regenerating epithelium. In vitro, the nuclear translocation of H2RSP was observed along with increasing cellular density, and an overexpression of H2RSP resulted in a reduced growth rate and enhanced invasiveness. H2RSP expression was down regulated in well-differentiated colorectal adenocarcinomas. However, a marked up regulation of the cytoplasmic H2RSP immunoreactivity was observed in cancer cells at the invasive front. These cells showed low MIB-1 labelling, an enhanced p16 expression and nuclear beta-catenin. The number of H2RSP-positive cells in the invasive front of well-differentiated adenocarcinomas was considerably higher in the cases with lymph node metastases than in node-negative ones. CONCLUSION: In the normal intestine, the nuclear accumulation of H2RSP is a marker of differentiated epithelial cells. Although H2RSP was down regulated in colorectal adenocarcinomas, a paradoxical up regulation was observed in actively invading carcinoma cells. H2RSP immunoreactivity at the invasive front may serve as a marker of invasive phenotype of well-differentiated colon cancers.

Adenocarcinoma↗

PubMed2005

Suppressor of cytokine signalling 1 in lymphocytes regulates the development of intestinal inflammation in mice.

BACKGROUND AND AIMS: Imbalance between pro- and anti-inflammatory cytokines produced by intestinal T cells induces inflammatory bowel diseases (IBD). However, the importance of regulation of cytokine signalling in IBD has not been fully clarified. We have demonstrated that suppressor of cytokine signalling 1 (SOCS1) is expressed in inflamed tissues in an experimental colitis model. In the present study, we investigated the role of SOCS1 in colitis models to clarify the mechanism of IBD development. METHODS: Intestinal T cells in transgenic mice expressing high levels of SOCS1 in lymphocytes (SOCS1Tg mice) were characterised by flow cytometric analysis and cytokine production from intestinal T cells was determined by ELISA. 2,4,6-Trinitrobenzene sulphonic acid (TNBS) induced colitis was induced in SOCS1Tg mice and severity was compared with control littermates by measurement of survival rates. Intracellular signalling was assessed by western blotting analysis. RESULTS: SOCS1Tg mice developed colitis spontaneously with age. Young SOCS1Tg mice less than 15 weeks of age, before the onset of colitis, were susceptible to TNBS induced colitis. Intestinal T cells of SOCS1Tg mice showed increased interferon gamma and tumour necrosis factor alpha production and decreased transforming growth factor beta production. Expression of cytotoxic T lymphocyte associated antigen 4 (CTLA-4), a negative regulator of T cell activation, in SOCS1Tg mice was severely impaired at the protein level although mRNA levels of CTLA-4 in SOCS1Tg mice were comparable with those in control mice. CONCLUSIONS: Our data suggest that SOCS1 plays an important role in the regulation of colitis by controlling intestinal T cell activation mediated through CTLA-4 expression.

Animals↗

PubMed2005

Constitutive IL-8 expression in cancer cells is associated with mutation of p53.

We previously reported that most cancer cell lines constitutively express various cytokines including IL-8. But how IL-8 gene expression is regulated in cancer cells is still unclear. p53 tumor suppressor gene plays an important role in the regulation of transcription and is mutated in cancer cell lines. We investigated whether p53 status affects the constitutive expression of IL-8 in human cancer cells. SUIT-2 and RERF-LCOK cancer cells constitutively produced high levels of IL-8 in culture medium. Both cell lines were shown to carry a p53 mutation, and constitutive NF-kappaB transcriptional activity. To analyze whether p53 status mediates IL-8 expression, the effect of wild-type p53 (wt-p53) gene transfer on activation of NF-kappaB was determined in both cell lines. ELISA showed that the IL-8 concentration in medium decreased dose dependently by transient expression of wt-p53. Western-blot analysis showed no marked change in NF-kappaB protein levels in cell nuclei. EMSA showed no repression of NF-kappaB binding activity after transient expression of wt-p53. In contrast, luciferase reporter studies indicated that transcriptional activity of NF-kappaB is suppressed by transfection of wt-p53. These results show that wt-p53 gene transfer inhibits IL-8 production and NF-kappaB transcription activity in cancer cells and suggest that constitutive IL-8 production in cancer cells is associated with mutation of p53.

Cell Line, Tumor↗

PubMed2004

Sex differences due to dehydroepiandrosterone (DHEA) feeding affecting dehydroepiandrosterone sulfate secretion in golden Syrian hamsters.

The metabolism of orally administered dehydroepiandrosterone (DHEA) by male and female golden Syrian hamsters was examined by quantification of DHEA and dehydroepiandrosterone sulfate (DHEAS) in gallbladder bile, urine and feces using high-performance liquid chromatography (HPLC). Plasma levels of DHEA and DHEAS were also determined by radioimmunoassay (RIA). After 5 days of oral DHEA administration (100 mg/kg body weight twice a day), RIA showed that plasma levels of DHEA and DHEAS were increased approximately 3-6 and 4-5 times, respectively, compared to controls. More than 95 % of circulating DHEA (S) in the peripheral blood was DHEAS. There was no significant sex difference in DHEAS plasma levels between male and female animals in the DHEA-supplemented group. However, 0.2 - 0.3 % of ingested DHEA was conjugated to DHEAS and excreted in urine by females, whereas less than 0.002 % was excreted in urine by males (p < 0.005). DHEAS was excreted in bile by males after DHEA supplementation, and the sex differences in DHEAS levels observed in bile were statistically significant (male, 18.7 +/- 7.5 vs. female, 5.6 +/- 3.1 micromol/l) (p < 0.005). Small amounts of ingested DHEA were excreted in an unchanged state in feces, and no sex difference was observed. These results suggest that there is a considerable sex difference in the conjugation and excretion of orally administered DHEA in the hamster.

Administration, Oral↗

PubMed2001

Liver metastasis from gallbladder carcinoma: anatomic correlation with cholecystic venous drainage demonstrated by helical computed tomography during injection of contrast medium in the cholecystic artery.

BACKGROUND: The current study evaluated whether the sites of liver metastasis from gallbladder carcinoma are correlated with areas of cholecystic venous drainage (CVD) utilizing helical computed tomography (CT) during the injection of contrast medium into the cholecystic artery (cholecystic artery CT). METHODS: Cholecystic artery CT scans were performed in 26 patients with gallbladder carcinoma. Liver metastases were examined retrospectively in these patients on CT, and the sites of liver metastasis and CVD were compared closely. The patients were divided into concurrent (those who had metastasis at the time of cholecystic artery CT), early postoperative metastasis (those who developed metastasis within 6 months after surgery), and late postoperative metastasis (those who developed metastasis more than 6 months after surgery) groups. The frequency of metastasis related to CVD was compared between the three groups. RESULTS: A total of 32 metastases were identified in 11 patients, 21 of which were related to CVD. Six patients were included in the concurrent metastasis group; 18 of 20 tumors were found to be related closely to CVD. There were two patients in the early postoperative metastasis group; all three of the tumors detected were found to be closely related to CVD. Three patients were subclassified as being in the late postoperative metastasis group; none of the nine tumors detected appeared to be in areas associated with CVD. CONCLUSIONS: The sites of liver metastases were found to be well correlated with the areas with CVD, particularly in the concurrent and early postoperative metastasis groups. CVD may be a useful marker of potential areas of liver metastasis from gallbladder carcinoma, particularly in patients with early stage metastasis.

Adult↗

PubMed2001

Laparoscopically assisted resection of choledochal cyst and Roux-en-Y reconstruction.

UNLABELLED: Laparoscopic surgery for a congenital choledochal cyst was accomplished in five of eight adult patients for whom it was attempted (63%). Creation of a Roux-en-Y jejunal limb by midline minilaparotomy and hepaticojejunostomy using a laparoscopic sewing instrument facilitated the procedure. BACKGROUND: Congenital choledochal cyst is a good indication for laparoscopic surgery. However, only two case reports are available at this writing. METHODS: Eight adult patients, ages 19 to 61 years (mean, 32.6 years), underwent laparoscopically assisted resection of the choledochal cyst and Roux-en-Y hepaticojejunostomy. RESULTS: The whole procedure was accomplished in five patients (63%). The duration of the procedure ranged from 525 to 680 min (average, 616 min). Open conversion in three patients was necessitated by severance of a small common hepatic duct because of disorientation caused by previous laparoscopic cholecystectomy, electrocautery injury to the common channel distal to the anomalous pancreaticobiliary junction, or heavy adhesion around the cyst secondary to recent severe cholangitis. Creation of a Roux-en-Y jejunal limb by midline minilaparotomy and hepaticojejunostomy using a laparoscopic sewing instrument facilitated the procedure. CONCLUSIONS: Laparoscopically assisted resection of the choledochal cyst and hepaticojejunostomy are technically feasible and deserve further clinical trials.

Adult↗

PubMed2001

Lower activity of CCAAT/enhancer-binding protein and expression of cyclin E, but not cyclin D1, activating protein-1 and p21(WAF1), after partial hepatectomy in obstructive jaundice.

CCAAT/enhancer-binding protein (C/EBP)-alpha stabilizes p21(WAF1), whereas activating protein-1 (AP-1) and C/EBP-beta enhance cyclin D1 and cyclin E expression, respectively, during the progress of liver regeneration. In this study, we investigated the differences in the transcription factors and cell cycle regulators between obstructive jaundiced and control rats before and after hepatectomy accompanied with a release of biliary obstruction by internal biliary drainage. The expressions and activities of C/EBP-alpha and -beta were significantly decreased in the jaundiced group concomitant with the significantly lower cyclin E expression after hepatectomy than in the controls. The activities of AP-1, cyclin D1 and p21(WAF1) were not significantly different between the two groups. These results suggest that obstructive jaundice inhibits hepatic expression and activity of C/EBP, resulting in the impaired cyclin E expression that is partly responsible for the cell cycle dysfunction after hepatectomy.

Animals↗

PubMed2001

Increased urinary excretion of bilirubin oxidative metabolites in septic patients: a new marker for oxidative stress in vivo.

BACKGROUND: Bilirubin oxidative metabolites (BOMs) are generated from bilirubin as a result of its scavenging action against free radicals. During sepsis, excess amounts of free radicals are produced, and they play an important role in the pathophysiological process. We studied whether urinary excretion of BOMs would increase under septic conditions in humans and compared BOM levels with other well-established clinical parameters of inflammation. METHODS: In 19 septic patients and 28 nonseptic control patients, the BOM concentrations in urine were measured by enzyme-linked immunosorbent assay with an anti-bilirubin antibody. RESULTS: Urinary BOM levels in septic patients were much higher than those in control patients (21.6 +/- 2.5 vs 1.4 +/- 0.4 micromol/g creatinine, P < 0.001). Although there was a linear correlation between urinary BOM and serum total bilirubin levels (r = 0.392, P = 0.008), serum bilirubin levels were not significantly higher in the septic group than in the control group (P = 0.072). BOM levels correlated with body temperature (r = 0.801, P < 0.001), white blood cell counts in the peripheral blood (r = 0.590, P < 0.001), serum C-reactive protein (r = 0.653, P < 0.001), and the acute physiological and chronic health evaluation (APACHE II) score (r = 0.467, P = 0.003). CONCLUSIONS: These results demonstrated a urinary increase in BOMs in septic patients. This increase indicates that urinary BOM level is a possible marker for continuous monitoring of sepsis severity in clinical practice.

APACHE↗

PubMed2001

FR167653 improves survival and pulmonary injury after partial hepatectomy under ischemia/reperfusion in rats.

BACKGROUND: FR167653 is a potent suppressant of production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta, which play an important role in hepatic and pulmonary injury due to ischemia/reperfusion of the liver and in liver regeneration after hepatectomy. We examined the effects of FR167653 on hepatectomy under ischemia/reperfusion in rats. METHODS: After initial 15-min ischemia and 5-min reperfusion, 70% hepatectomy was performed during the second 15-min ischemia period in FR167653-treated (FR group) and saline-treated (saline group) rats. The survival rate, relative liver weight, TNF-alpha, IL-1 beta, DNA synthesis rate of the remnant liver, and histological change and adhesion molecule (ICAM-1) of the lung were examined. Serum glutamic pyruvic transaminase and hepatic malondialdehyde were also measured. RESULTS: Expressions of TNF-alpha and IL-1 beta in the remnant liver were significantly inhibited in the FR group compared to the saline group. The survival was significantly better and pulmonary damage was less in the FR group after hepatectomy under ischemia/reperfusion. ICAM-1 expression of the lung was not altered after hepatectomy and was not significantly different between the two groups. Liver regeneration and injury were not significantly different between the two groups. CONCLUSION: FR167653 does not affect liver injury and regeneration after hepatectomy under ischemia/reperfusion, while it ameliorates pulmonary injury and improves the survival.

Alanine Transaminase↗

PubMed2001

Therapeutic efficacy of G207, a conditionally replicating herpes simplex virus type 1 mutant, for gallbladder carcinoma in immunocompetent hamsters.

Gallbladder cancer is an extremely difficult disease to cure once metastases occur. In this paper, we explored the potential of G207, an oncolytic, replication-competent herpes simplex virus type 1 mutant, as a new therapeutic means for gallbladder cancer. Gallbladder carcinoma cell lines (four human and one hamster) showed nearly total cell killing within 72 h of G207 infection at a m.o.i. of 0.25 to 2.5 in vitro. The susceptibility to G207 cytopathic activity correlated with the infection efficiency demonstrated by lacZ expression. Intraneoplastic inoculation of G207 (1 x 10(7) pfu) in immunocompetent hamsters bearing established subcutaneous KIGB-5 tumors caused a significant inhibition of tumor growth and prolongation of survival. Repeated inoculations (three times with 4-day intervals) were significantly more efficacious than a single inoculation. In hamsters with bilateral subcutaneous KIGB-5 tumors, inoculation of one tumor alone with G207 caused regression or growth reduction of uninoculated tumors as well as inoculated tumors. In athymic mice, however, the anti-tumor effect was largely reduced in inoculated tumors and completely abolished in remote tumors, suggesting large contribution of T-cell-mediated immune responses to both local and systemic anti-tumor effect of G207. These results indicate that G207 may be useful as a new strategy for gallbladder cancer treatment.

Animals↗

PubMed2001

Surgical bypass versus metallic stent for unresectable pancreatic cancer.

With the development of interventional radiology and endoscopy, the practice of inserting expandable metallic stents for malignant jaundice has become widespread. Many studies have compared surgical bypass with polyethylene stents, or metallic stents with polyethylene stents. However, few data are available on the comparison of surgical bypass and metallic stents. The aim of this study was to compare the patient's postprocedure course and the cost performance of surgical bypass and metallic stents in patients with unresectable pancreatic cancer. The parameters analyzed were the rates of procedural and therapeutic success, duration of hospital stay, prevalence of early and late complications, cost performance, and prognosis. The rates of procedural and therapeutic success were excellent with both palliative treatments. With surgical bypass, there was a low prevalence of late complications, but duodenal obstruction sometimes occurred in patients without gastric bypass. With metallic stents, there was shorter hospitalization and lower cost, but a higher prevalence of late complications. Stent occlusion tended to occur in patients with uncovered metallic stents. There was no difference in the prognosis between the two palliative treatments. Thus, in consideration of the poor prognosis of pancreatic cancer, in patients with unresectable pancreatic cancer, insertion of covered metallic stents would be preferable to surgical bypass, because of the subsequent short hospitalization and the low cost. On the other hand, in patients with a relatively long expected prognosis, or in those with existing duodenal obstruction, biliary bypass with gastrojejunostomy may provide an advantage.

Adult↗

PubMed2001

Comparison of laparoscopic versus open cholecystectomy in patients with cardiac valve replacement.

To evaluate the benefits and safety of laparoscopic cholecystectomy (LC) in patients with cardiac valve replacement (which frequently leads to cholelithiasis), 12 patients with cholelithiasis associated with cardiac valve replacement were studied. The patients were divided into two groups, of 6 patients each, according to the type of operation performed, open cholecystectomy (OC) or LC. The postoperative course was monitored with respect to laboratory data on postoperative days (POD) 1, 3, and 7. The mean duration of operation, blood loss, days to food resumption, length of hospital stay, and morbidity were compared between the two groups. Significant differences (P < 0.05) were found between the OC and LC groups in white blood cell counts on POD 1 (12 980 +/- 3040/mm3 vs 8300 +/- 1590/mm3), days to food resumption (2.7 +/- 0.4 days vs 1.0 +/- 0.7 days), and length of postoperative stay (15.8 +/- 1.0 days vs 10.8 +/- 1.6 days). There were no complications in the LC group, but 1 patient in the OC group had heart failure postoperatively. Our findings indicate the efficacy and safety of LC in patients with cardiac valve replacement.

Adult↗

PubMed2001

Periampullary choledochoduodenal fistula in ampullary carcinoma.

Most patients with ampullary carcinoma have obstructive jaundice without cholangitis. We experienced a patient with ampullary carcinoma who presented with obstructive jaundice and cholangitis, probably because of an accompanying periampullary choledochoduodenal fistula. A 77-year-old Japanese man had jaundice, high fever, and upper abdominal pain and was diagnosed, at another hospital, with obstructive cholangitis. On admission to our hospital, his symptoms and signs had subsided spontaneously. Abdominal ultrasonography showed cholecystolithiasis and dilatation of the common bile duct. Duodenoscopy showed an ulcerating tumor at the oral prominence of the ampulla of Vater and a periampullary choledochoduodenal fistula at the bottom of the ulcer. Biopsy from the fistula showed well differentiated adenocarcinoma. With a diagnosis of ampullary carcinoma with fistula formation, the patient underwent pylorus-preserving pancreatoduodenectomy. The diagnosis was confirmed by histology. This communication presents a unique case of ampullary carcinoma that caused obstructive jaundice, which subsided spontaneously but was associated with cholangitis caused by the divergent effects of the periampullary choledochoduodenal fistula formed by the carcinoma.

Aged↗

PubMed2001

Effect of prepyloric gastric transection and anastomosis on sphincter of Oddi cyclic motility in conscious dogs.

PURPOSE: We previously reported significant changes in sphincter of Oddi cyclic motility after proximal duodenal transection and anastomosis. However, the role of intrinsic myoneural continuity between the antrum and duodenum in this respect is not understood. The aim of this study was to elucidate the effects of prepyloric gastric transection on sphincter of Oddi motility in animals in the conscious state. METHODS: Pressures in the bile duct, duodenum, stomach, and sphincter of Oddi and their response to an injection of cholecystokinin-octapeptide were measured in four conscious dogs, with a duodenal cannula, before and after gastric transection and anastomosis 1.5 cm proximal to the pylorus. RESULTS: Gastric transection did not affect the initiation and propagation of the gastroduodenal migration motor complex. Biliary pressure (5.7 +/- 0.15 to 5.5 +/- 0.2 mmHg; P = 0.91), sphincter of Oddi basal pressure (10.6 +/- 0.3 to 10.7 +/- 0.2 mmHg; P = 0.97), and amplitude (26.0 +/- 1.2 to 32.9 +/- 1.7 mmHg; P = 0.304) did not change after gastric transection. Biliary pressure decreased from phase II to phase III of the duodenal migrating motor complex. Cholecystokinin-octapeptide inhibited sphincter of Oddi phasic waves before and after gastric transection. CONCLUSIONS: Intrinsic myoneural transection at the prepyloric region does not influence sphincter of Oddi cyclic motility. Preservation of pyloroduodenal myoneural continuity in pylorus-preserving gastrectomy would be beneficial to maintain normal sphincter of Oddi motility.

Anastomosis, Surgical↗

PubMed2001

Quality of life after pylorus-preserving pancreatoduodenectomy.

BACKGROUND: With increasing numbers of long-term survivors after pylorus-preserving pancreatoduodenectomy (PPPD), postoperative quality of life (QOL) has become a great concern. However, few reports are available on data of the postoperative changes in QOL after PPPD. METHODS: A total of 20 patients were studied regarding QOL before and at short term (within 2 months), intermediate term (6 months), and long term (1 year) after PPPD, using a questionnaire. The questionnaire consisted of 13 physical and 10 psychosocial items. The medical records were also reviewed to evaluate objective nutritional status. Factors predicting delayed recovery of QOL were examined at intermediate term by univariate and multivariate analyses. RESULTS: Overall and physical QOL scores returned to the preoperative level at intermediate term after PPPD, showing parallel changes with the objective nutritional status. However, the scores of psychosocial condition, which reflected the patient's mental health, remained low even at long term. QOL scores at intermediate term in patients with pancreatic carcinoma were significantly lower than those with other diseases. Univariate analysis showed that preoperative body weight loss, impaired preoperative pancreatic exocrine function, long operative time, intraoperative radiotherapy, pancreatic carcinoma, and postoperative diarrhea were factors predicting the delayed recovery of QOL. Multivariate analysis revealed that preoperative pancreatic exocrine function significantly affected the delayed recovery of QOL. CONCLUSIONS: Preoperative supplement of pancreatic enzymes together with perioperative mental care would improve QOL at long term after PPPD.

Adult↗

PubMed2001

Postoperative pancreatic exocrine function influences body weight maintenance after pylorus-preserving pancreatoduodenectomy.

BACKGROUND: Most patients who undergo pylorus-preserving pancreatoduodenectomy (PPPD) are able to gain their weight postoperatively. However, sometimes patients experience a lack of weight gain even at long term after PPPD. The aim of this study was to examine factors influencing a body weight change after PPPD. METHODS: In 34 Japanese patients with PPPD, 28 clinical parameters were assessed as possible factors affecting body weight maintenance at long term (1 year) after the operation by univariate and multivariate analyses. RESULTS: Univariate analysis showed that long operation time (P = 0.02), extended retroperitoneal lymph node dissection (P = 0.0005), intraoperative radiotherapy (P = 0.02), adjuvant postoperative chemotherapy (P = 0.02), histopathological diagnosis of pancreatic cancer (P = 0.02), postoperative ulceration (P = 0.007), and insufficient postoperative pancreatic exocrine function (P = 0.002) were significantly related with the lack of weight gain at long term after PPPD. Multivariate analysis regarding the seven profound factors revealed that the insufficient postoperative pancreatic exocrine function significantly affected the lack of weight gain after PPPD. The use of ordinary amount of pancreatic exocrine enzymes did not influence the weight gain after PPPD (P = 0.23). CONCLUSIONS: In patients refractory to an ordinary amount of medicine, a large dosage of enzymes may be necessary to gain weight after PPPD.

Adult↗

PubMed2001

Is peripapillary choledochoduodenal fistula an indication for endoscopic sphincterotomy?

BACKGROUND: Most patients with a peripapillary choledochoduodenal fistula undergo fistulotomy by endoscopic sphincterotomy for the treatment of bile duct stones. However, whether sphincterotomy should be performed in patients with the fistula but without stones is controversial. METHODS: Among 165 patients in whom a benign peripapillary choledochoduodenal fistula was diagnosed at ERCP, the clinical outcome was retrospectively analyzed and compared between those who underwent fistulotomy by endoscopic sphincterotomy (group 1) and those whose fistula was left untreated (group 2). All patients with hepatolithiasis, residual stones, biliary diversion, or transduodenal papilloplasty were excluded (32, leaving 133). Fistulas were divided into types I and II according to the location of the fistula (Ikeda classification). RESULTS: Follow-up data collected during a median period of 124 months were available for 127 of 133 patients (95%), 76 in group 1 and 53 in group 2. Late complications were bile duct stone recurrence (17 patients), acute cholangitis (7 patients), and biliary carcinoma (2 patients). The incidence of stone recurrence was not significantly different between the 2 groups (p = 0.1). In group 2, 4 patients (8%) with an untreated type II fistula had 1 to 3 episodes of presumed reflux cholangitis, which resolved quickly with conservative treatment. CONCLUSIONS: Endoscopic sphincterotomy is not always necessary for peripapillary choledochoduodenal fistulas if bile duct stones are absent because reflux cholangitis is a relatively rare complication that can be easily managed.

Adult↗

PubMed2001

Effects of internal biliary bypass on the regulation of hepatic cholesterol 7alpha-hydroxylase activity in rats.

In order to re-evaluate the importance of the enterohepatic circulation of bile acid in the regulation of the activities of hepatic cholesterol 7alpha-hydroxylase, bile acid metabolism was examined in internal biliary bypass models of rats. A polyethylene tube was inserted into the common bile duct and another side of the tube was placed in the duodenum (DD), lower jejunum (JD), cecum (CeD), or transverse colon (CoD) as internal biliary bypass models and in the urinary bladder as an external biliary drainage (ED). After bile diversion for 7 days in each group, hepatic cholesterol 7alpha-hydroxylase activities, bile acid concentrations in bile, serum, and portal vein, biliary bile acid compositions, and intestinal absorption rates of infused labeled taurocholic acid were analyzed. Hepatic cholesterol 7alpha-hydroxylase activity was similar in the JD group compared with the DD group, however, it was significantly up-regulated in the CeD (227% of the DD group), CoD (312%), and ED groups (316%). Biliary, serum, and portal bile acid concentrations were not significantly changed in the DD, JD, and CeD groups but those were significantly lower in the CoD and ED groups compared with the DD group. The proportion of the secondary bile acids was significantly increased in the CeD group and was decreased in the CoD and ED groups. The absorption rate of taurocholic acid was almost 100%, 56%, and 23% in the JD, CeD, and the CoD group, respectively. As the cholesterol 7alpha-hydroxylase activity was not significantly changed in the JD group and the predominance of secondary bile acids did not suppress the enzyme activity in the CeD group, the luminal factor, which is absorbed in the presence of bile acids, and the bile acid metabolites are not likely the regulatory factor. The cholesterol 7alpha-hydroxylase activity seems to be primarily regulated by the intestinal absorption of bile acids and partly by the intestinal mucosal factor which is linked to the intestinal bile acid absorption.

Animals↗