Mechanism of benign biliary stricture: A morphological and immunohistochemical study

Long-Term Outcomes Following Surgical Repair for Post-cholecystectomy Biliary Strictures

INTRODUCTION

Bile duct injuries (BDIs) are a serious complication of cholecystectomy. Strictures that form after major injuries ultimately require surgical repair. This study aimed to analyse our experience with the surgical repair of post-cholecystectomy biliary strictures (PCBS).

METHODS

Patients who underwent surgical repair for PCBS between January 2013 and March 2020 were retrospectively reviewed. The strictures were classified using the Bismuth system. Delayed repair with Roux-en-Y hepaticojejunostomy was performed using the Hepp-Couinaud technique. Outcomes were graded according to McDonald's criteria. Statistical analysis was performed to identify factors influencing the outcomes.

RESULTS

Sixty-eight patients underwent repair for PCBS. Forty-five patients presented within one month and eight patients presented late after six months. Presenting symptoms were jaundice, external biliary fistula, biliomas, cholangitis and peritonitis. Portal hypertension was present in two patients. The median interval for definitive repair was 22 weeks. The median hospital stay was 9.5 days. Eighteen patients had postoperative complications. One patient had postoperative mortality due to uncorrectable coagulopathy. With a median follow-up of 54 months, successful outcomes were achieved in 61 (90%) patients. Four patients had anastomotic strictures evident at two, four, five and eight years after repair. Portal hypertension and postoperative complications were the variables associated with poor outcomes.

CONCLUSION

BDIs following cholecystectomy are a devastating complication. Surgical repair for biliary strictures yields durable long-term outcomes with early identification and timely referral to a tertiary care centre where standardized techniques for biliary reconstruction are followed.

Long-term outcome of combined radiologic and surgical strategy for the management of biliary complications after pediatric liver transplantation

OBJECTIVES

We aimed to analyze the risk factors for management failure of BC after pediatric liver transplantation (pLT) by retrospectively analyzing primary pLT performed between 1997 and 2018 (n = 620 patients).

RESULTS

In all, 117/620 patients (19%) developed BC. The median (range) follow-up was 9 (1.4-21) years. Patient survival at 1, 5 and 10 years was 88.9%, 85.7%, 84.4% and liver graft survival was 82.4%, 77.4%, and 74.3% respectively. Graft not patient survival was impaired by BC (p = 0.01). Multivariate analysis identified the number of dilatation courses > 2 (p = 0.008), prolonged cold ischemia time (p = 0.004), anastomosed multiple biliary ducts (p = 0.019) and hepatic artery thrombosis (p = 0.01) as factors associated with impaired graft survival. The number of dilatation courses > 2 (p < 0.001) and intrahepatic vs anastomotic stricture (p = 0.014) were associated with management failure. Thus, repeated (> 2) radiologic dilatation courses are associated with impaired graft survival and management failure. Overall, graft but not patient survival was impaired by BC.

The short- and long-term outcome after the surgical management of common bile duct stones in a tertiary referral hospital

BACKGROUND

The removal of common bile duct stones by endoscopic retrograde cholangiopancreatography (ERCP) shows excellent results with low complication rates and is therefore considered a gold standard. However, in case of stones non-removable by ERCP, surgical extraction is needed. The surgical approach is still controversial and clinical guidelines are missing. This study aims to analyze the outcomes of patients treated with choledochotomy or hepaticojejunostomy for common bile duct stones.

METHODS

All patients who underwent choledochotomy or hepaticojejunostomy for common bile duct stones at a tertiary referral hospital over 11 years were included. The analyzed data contains basic demographics, diagnostics, surgical parameters, length of hospitalization, and morbidity and mortality.

RESULTS

Over the study period, 4375 patients underwent cholecystectomy, and 655 received an ERCP with stone extraction, with 48 of these patients receiving subsequent surgical treatment. ERCP was attempted in 23/30 (77%) of the choledochotomy patients pre/intraoperatively and 11/18 (56%) in hepaticojejunostomy patients. The 30-day major complication rate (Clavien-Dindo > II) was 1/30 (3%) in the choledochotomy group and 2/18 (11%) in the hepaticojejunostomy group. Complications after 30 days occurred in 3/30 (10%) patients and 2/18 (11%), respectively, and no mortality occurred.

CONCLUSION

ERCP should still be considered the gold standard, although due to low short- and long-term morbidity rates, choledochotomy and hepaticojejunostomy represent effective surgical solutions for common bile duct stones.

Surgical Management of Recurrence of Primary Intrahepatic Bile Duct Stones

BACKGROUND

The surgical treatment of primary intrahepatic bile duct stones is associated with high rates of postoperative complications, stone recurrence, and reoperation. This study aimed to report an 11-year experience in the management of postoperative recurrence of intrahepatic bile duct stones, analyze the causes of the reoperation, and establish appropriate surgical procedures.

MATERIALS AND METHODS

The records of 148 patients with postoperative recurrence of primary intrahepatic bile duct stones treated from January 2005 to December 2015 were retrospectively reviewed. Prior surgical treatment and postoperative data were analyzed to investigate possible causes of recurrence and reoperation.

RESULTS

All patients with a prior cholangiojejunostomy (n = 61) developed biliary stenosis (100%). Of the 86 patients without cholangiojejunostomy, 71 (82.56%) had abnormalities in the structure and function of the lower end of the common bile duct, and 86 had hilar and intrahepatic bile duct stenosis. Of all 148 patients, 136 (91.89%) had positive intraoperative bile cultures. Patients were treated with a modified surgical procedure, and the combined excellent and good rate of long-term outcomes reached 85.48% (106/124). The stone recurrence rate of the 124 patients decreased from 100% (124/124) of the prior operation to 5.65% (7/124) during the reoperation.

CONCLUSIONS

The pathogenesis of primary intrahepatic bile duct stones is associated with biliary infection and intrahepatic bile duct cholestasis. According to the etiology and pathogenic mechanism, surgical procedures that improve long-term outcomes and reduce postoperative recurrence include bile duct exploration with stone extraction, partial hepatectomy, hilar ductoplasty, and Roux-en-Y hepaticojejunostomy.

Local application of triamcinolone acetonide-conjugated chitosan membrane to prevent benign biliary stricture

Benign biliary stricture (BBS) is the proliferation of fibrous tissue of the biliary tract caused by the biliary operation, bile duct stones, cholangitis, trauma, and other etiologies due to scar contracture. Recent therapeutic strategies to suppress stenosis are insufficient. Here, we developed a sustained-release membrane (SM) of triamcinolone acetonide (TA) with N-succinyl hydroxypropyl chitosan (TASM) for inhibiting fibroblast proliferation in vitro and bile duct hyperplasia in the rabbit model for benign biliary stricture formation. The TASM were successfully placed in 45 of 50 rabbits. Evaluation of subcutaneous stimulation and acute liver injury confirms the safety of TASM in vivo. Compared to the control group, the TASM can significantly inhibit the proliferation of scar muscle fibroblasts in vitro. ELISA and immunofluorescence showed TASM could increase bFGF level and inhibit expression of TGFβ1 and αSMA. Cholangiographic and histologic examinations demonstrated significantly decreased tissue hyperplasia in the TASM groups compared with the model group. The immunohistochemical staining showed that TASM could reduce the level of cytokine-induced scars and inhibit the proliferation of myofibroblasts. Taken together, the chitosan membrane chemically conjugated with TA can effectively inhibit the benign biliary stricture. Further clinical usage of this membrane may effectively reduce the occurrence of benign biliary stricture.

Preclinical evaluation of endoscopic placement of a steroid-eluting metal stent in an in vivo porcine benign biliary stricture model

Treatment of benign biliary strictures (BBS) using fully covered self-expandable metal stents (FCSEMS) has a high success rate, but recurrence can occur. Corticosteroids may be useful based on their anti-fibrotic and anti-inflammatory effects. We investigated the safety and efficacy of corticosteroid-eluting FCSEMS in an animal model. BBSs were created by radiofrequency ablation in 12 mini-pigs. Four weeks later, FCSEMS coated with 0 mg (control), 15 mg (steroid 1 × group), or 30 mg (steroid 2 × group) triamcinolone were inserted endoscopically. The in vitro drug release assay revealed that the optimal stent had 15 mg of triamcinolone and a hydrophilic membrane. No transmural necrosis or perforation occurred in any animal. Fibrous wall thickness tended to decrease macroscopically and microscopically in a triamcinolone dose-dependent manner (control vs. steroid 2 × group: 773.1 vs. 468.5 µm, P = 0.037). Thickness also decreased over time in the steroid 2 × group (3 days vs. 4 weeks: 907.9 vs. 468.5 µm, P = 0.025). Blood parameters tended to improve after stent insertion. In a porcine BBS model, steroid-eluting FCSEMS showed potential as a safe and effective treatment modality to reduce fibrotic tissue. Studies are required to confirm their safety and efficacy in humans with refractory BBS.

The Utility of Biliary Manometry in Assessing Early Catheter Removal After Percutaneous Balloon Dilatation of Hepaticojejunostomy Strictures

Background and objective

Percutaneous balloon dilatation followed by long-term internal-external biliary catheter (IEBC) placement is the standard radiological management for postoperative hepaticojejunostomy (HJ) strictures. The treatment is considered successful when cholangiography shows a free flow of contrast across the anastomosis and the patient passes a "clinical test". However, these tests may not be suitable predictors of long-term successful treatment outcomes. The purpose of this study was to assess the utility of biliary manometry in the evaluation of successful treatment outcomes after HJ stricture dilatation and IEBC placement and its efficacy as a tool for early catheter removal.

Patients and methods

A total of 14 patients underwent percutaneous balloon dilatation of HJ strictures with IEBC placement. A two-to-three-month interval was maintained between sessions of exchanging or upsizing IEBCs. Biliary manometry was performed after a mean duration of 6.3 months. Intra-biliary pressure of <15 mmHg was considered as the success threshold.

Results

Among the 14 patients, 11 patients passed initial manometry and had their IEBCs removed and were followed up for a mean duration of 47.8 months. Of these, one patient developed biliary obstruction after six months and underwent repeat HJ stricture dilatation and long-term IEBC placement. Three patients failed manometry and underwent re-dilatation of HJ strictures with IEBC placement. Using Kaplan-Meier survival analysis, the probability of patients remaining stricture-free after HJ stricture dilatation was found to be 100% at three months and 91% at six, 12, 18, 24, 36, and 47.8 months.

Conclusion

Biliary manometry prevents subjective variations in determining treatment endpoints and helps to assess early catheter removal after percutaneous balloon dilatation of HJ strictures.

Resection of extrahepatic bile ducts with partial hepatectomy for treating intra- and extrahepatic hepatolithiasis

Background

To evaluate the efficacy and safety of our new surgical procedures for primary intra- and extrahepatic hepatolithiasis. Hepatolithiasis is an intractable disease with frequent recurrences.

Methods

From 1996 to 2005, 142 patients with intrahepatic and/or extrahepatic hepatolithiasis treated with the conventional surgical methods were included as the control group, while 128 consecutive patients treated with new surgical methods from 2006 to 2015 were included as the observation group. The new surgical procedures included a comprehensive intraoperative exploration of the bile ducts, focusing on the structure and function of the hilar bile duct and duodenal papilla, exploration of the affected liver, and bile culture.

Results

The observation group had a significantly higher complete stone clearance rate than the control group (100% vs. 65.96%). The observation group had significantly lower incidences of cholangitis and bile duct stones, as well as a higher excellent and good long-term surgical efficacy rate (86.24% vs. 52.73%). Multivariate Cox analysis showed that the control group had a higher risk for fair + poor efficacy than the observation group (HR: 8.47).

Conclusions

Our new surgical procedures are safe and can provide a good long-term efficacy for treating primary hepatolithiasis intra- and extrahepatic hepatolithiasis.

Percutaneous Balloon Dilatation for Hepaticojejunostomy Stricture Following Paediatric Liver Transplantation: Long-Term Results of an Institutional "Three-Session" Protocol

PURPOSE

The aim of this study was to report the long-term results of an institutional protocol of percutaneous biliary balloon dilatation (PBBD) on paediatric patients with benign anastomotic stricture after liver transplantation. As a secondary objective, we evaluated risk factors associated with post-treatment re-stricture.

MATERIALS AND METHODS

Fourteen paediatric, post-liver transplant patients with benign anastomotic stricture of Roux-en-Y hepaticojejunostomy were included. All patients underwent the same treatment protocol of three PBBD procedures with 15-day intervals. Clinical outcome was analysed using the Terblanche classification. Primary patency rate was assessed with the Kaplan-Meier test.

RESULTS

All patients had an initial successful result (Terblanche grade, excellent/good) after PBBD. At the end of the follow-up time of 35.7 ± 21.1 months (CI95%, 23.5-47.9), 10 patients persisted with excellent/good grading, while the remaining 4 had re-stricture, all of the latter occurring within the first 19 months. Patency rate after percutaneous treatment at 1, 3, and 5 years were 85.7%, 70%, and 70%, respectively. History of major complication after liver transplantation was associated with 5 times higher risk of re-stricture, HR 5.48 [95% CI, 2.18-8.78], p = 0.018.

CONCLUSION

In paediatric patients with benign anastomotic stricture of hepaticojejunostomy after liver transplantation, the "Three-session" percutaneous biliary balloon dilatation protocol is associated with a high rate of long-term success. In this limited series, the history of post-liver transplant major complication, defined as complications requiring a reintervention under general anaesthesia or advanced life support, seems to be an independent risk factor for stricture recurrence.

Risk factors for anastomotic stricture after hepaticojejunostomy for bile duct injury-A systematic review and meta-analysis

BACKGROUND

After major bile duct injury, hepaticojejunostomy can result in good long-term patency, but anastomotic stricture is a common cause of long-term morbidity. There is a need to assimilate high-level evidence to establish risk factors for development of anastomotic stricture after hepaticojejunostomy for bile duct injury.

METHODS

A systematic review of studies reporting the rate of anastomotic stricture after hepaticojejunostomy for bile duct injury was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Meta-analyses of proposed risk factors were then performed.

RESULTS

Meta-analysis included 5 factors (n = 2,155 patients, 17 studies). Concomitant vascular injury (odds ratio 4.96; 95% confidence interval 1.92-12.86; P = .001), postrepair bile leak (odds ratio: 8.03; 95% confidence interval 2.04-31.71; P = .003), and repair by nonspecialist surgeon (odds ratio 11.29; 95% confidence interval 5.21-24.47; P < .0001) increased the rate of anastomotic stricture of hepaticojejunostomy after bile duct injury. Level of injury according to the Strasberg Grade did not significantly affect the rate of anastomotic stricture (odds ratio: 0.97; 95% confidence interval 0.45-2.10; P = .93). Owing to heterogeneity of reporting, it was not possible to perform a meta-analysis for the impact of timing of repair on anastomotic stricture rate.

CONCLUSION

The only modifiable risk factor, repair by a nonspecialist surgeon, demonstrates the importance of broad awareness of these data. Knowledge of these risk factors may permit risk stratification of follow-up, better informed consent, and understanding of prognosis.

Causes and Countermeasures of Difficult Selective Biliary Cannulation: A Large Sample Size Retrospective Study

OBJECTIVE

Selective biliary cannulation is a difficult part of endoscopic retrograde cholangiopancreatography (ERCP). Therefore, endoscopists have focused on how to improve the cannulation success rate and reduce the postoperative complication rate. This study aims to provide practical advice on safe operation for endoscopists.

MATERIALS AND METHODS

Data from the ERCP database of our medical center from January 2008 to December 2017 were retrospectively reviewed. All patients underwent ERCP for the first time. Data pertaining to diseases, anatomic factors, difficult cannulation rates, cannulation success rates, and postoperative complication rates for various assistive cannulation techniques were analyzed by using the Pearson χ2 tests and Fisher exact tests.

RESULTS

The difficult cannulation rate was 8.1%. The main influencing factors were benign and malignant biliary stricture, duodenal papillae or ampullary tumors, thick and long duodenal papillae, peridiverticular papillae, ectopic papillae, edematous papillae, ulcerative papillae, anomalous pancreaticobiliary junction, and Billroth II gastrectomy. The postoperative complication rates and overall cannulation success rates of 7 assistive techniques were not statistically different (P>0.05), but the overall complication rates were statistically different (P<0.05). Needle-knife precut sphincterotomy had the highest rate of complications.

CONCLUSIONS

Benign and malignant biliary stricture, duodenal papillae or ampullary tumors, thick and long duodenal papillae, peridiverticular papillae, ectopic papillae, edematous papillae, ulcerative papillae, anomalous pancreaticobiliary junction, and Billroth II gastrectomy were the main factors of difficult selective biliary cannulation. The overall incidence of needle-knife precut sphincterotomy complications was higher than that of other techniques, but various assistive techniques were safe and effective in our single center.

Surgical strategy for recurrent common bile duct stones: a 10-year experience of a single center

Recurrence of common bile duct stones (CBDS) is common after surgical stone extraction, but the causes of recurrence are not fully understood. This study aimed to report the experience of treating recurrent CBDS. A total of 106 consecutive cases of recurrent CBDS treated from January 2006 to December 2015 were included. During surgery, the choledochoscopic pass-through test was performed to assess the structure and function of the duodenal papilla. The choledochoscopic pass-through test revealed 62 patients (58.49%) with incomplete closure of the lower end of the common bile duct, and 28 (26.42%) with stenosis at the lower common bile duct. Intra-operative bile bacterial culture was positive in 98 (92.45%) patients. The rate of complete stone clearance was 99.1%. The total recurrence rate of CBDS was 3.13%. The long-term success rate of surgical treatment (excellent and good) reached 92.7% .Duodenal papilla (Oddi sphincter) dysfunction is the main cause of recurrent CBDS. Common bile duct exploration with stone extraction, hilar ductoplasty, and Roux-en-Y hepaticojejunostomy can effectively eliminate the recurrence of CBDS and reduce the incidence of post-hepaticojejunostomy complications. Thus, it is an optimal surgical procedure for recurrent CBDS.

A Novel Rabbit Model for Benign Biliary Stricture Formation and the Effects of Medication Infusions on Stricture Formation

BACKGROUND

Benign biliary stricture (BBS) is highly refractory. Currently, there is no effective strategy for prevention of BBS recurrence. The aim of this study is to establish a novel BBS rabbit model and to investigate the efficacy of biliary infusion with anti-proliferative medications for treating BBS.

METHOD

A BBS model was established via surgical injury and biliary infection. The biliary infusion tube was inserted into the common bile duct via the stump of cystic duct after cholecystectomy. Biliary infusions with Rapamycin, Pirfenidone and Fasudil were performed daily during the 4 weeks following the surgery. The wall thickness and luminal area of the bile duct were assessed.

RESULTS

All rabbits formed BBS after surgery. The mortality rate was 13% (8/60) and tube withdrawal rate was 4% (2/48). The thickness of the bile duct wall was significantly reduced; whereas the luminal area of the bile duct was dramatically enlarged in the Rapamycin or the Pirfenidone treated group, compared to the saline treated group. Furthermore, the local treatment significantly decreased the levels of proliferation makers, including PCNA, Collagen I and fibrogenic mediators, including ACTA2 and TGF-beta.

CONCLUSION

We have established a novel animal model for BBS formation. We have further demonstrated that biliary infusion with Rapamycin or Pirfenidone limits the biliary strictures through inhibiting the proliferation of the bile duct wall in this model. This may represent a new avenue for preventing biliary restenosis.

Effect of tamoxifen on fibrosis, collagen content and transforming growth factor-β1, -β2 and -β3 expression in common bile duct anastomosis of pigs

End-to-end anastomosis in the treatment for bile duct injury during laparoscopic cholecystectomy has been associated with stricture formation. The aim of this study was to experimentally investigate the effect of oral tamoxifen (tmx) treatment on fibrosis, collagen content and transforming growth factor-β1, -β2 and -β3 expression in common bile duct anastomosis of pigs. Twenty-six pigs were divided into three groups [sham (n = 8), control (n = 9) and tmx (n = 9)]. The common bile ducts were transected and anastomosed in the control and tmx groups. Tmx (40 mg/day) was administered orally to the tmx group, and the animals were euthanized after 60 days. Fibrosis was analysed by Masson's trichrome staining. Picrosirius red was used to quantify the total collagen content and collagen type I/III ratio. mRNA expression of transforming growth factor (TGF)-β1, -β2 and -β3 was quantified using real-time polymerase chain reaction (qRT-PCR). The control and study groups exhibited higher fibrosis than the sham group, and the study group showed lower fibrosis than the control group (P = 0.011). The control and tmx groups had higher total collagen content than the sham group (P = 0.003). The collagen type I/III ratio was higher in the control group than in the sham and tmx groups (P = 0.015). There were no significant differences in the mRNA expression of TGF-β1, -β2 and -β3 among the groups (P > 0.05). Tmx decreased fibrosis and prevented the change in collagen type I/III ratio caused by the procedure.

Delayed rearterialization unlikely leads to nonanastomotic stricture but causes temporary injury on bile duct after liver transplantation

Nonanastomotic strictures (NAS) are common biliary complications after liver transplantation (LT). Delayed rearterialization induces biliary injury in several hours. However, whether this injury can be prolonged remains unknown. The correlation of this injury with NAS occurrence remains obscure. Different delayed rearterialization times were compared using a porcine LT model. Morphological and functional changes in bile canaliculus were evaluated by transmission electron microscopy and real-time PCR. Immunohistochemistry and TUNEL were performed to validate intrahepatic bile duct injury. Three months after LT was performed, biliary duct stricture was determined by cholangiography; the tissue of common bile duct was detected by real-time PCR. Bile canaliculi were impaired in early postoperative stage and then exacerbated as delayed rearterialization time was prolonged. Nevertheless, damaged bile canaliculi could fully recover in subsequent months. TNF-α and TGF-β expressions and apoptosis cell ratio increased in the intrahepatic bile duct only during early postoperative period in a time-dependent manner. No abnormality was observed by cholangiography and common bile duct examination after 3 months. Delayed rearterialization caused temporary injury to bile canaliculi and intrahepatic bile duct in a time-dependent manner. Injury could be fully treated in succeeding months. Solo delayed rearterialization cannot induce NAS after LT.

Repair of extrahepatic bile duct defect using a collagen patch in a Swine model

Extrahepatic bile duct (EBD) injury can happen during surgery. To repair a defect of the EBD and prevent postoperative biliary complications, a collagen membrane was designed. The collagen material was porous, biocompatible, and degradable and could maintain its shape in bile soaking for about 4 weeks. The goal was to induce rapid bile duct tissue regeneration. Twenty Chinese experimental hybrid pigs were used in this study and divided into a patch group and a control group. A spindle-shaped defect (20 mm × 6 mm) was made in the anterior wall of the lower EBD in the swine model, and then the defect was reconstructed using a collagen patch with a drainage tube and wrapped with greater omentum. Ultrasound was performed at 2, 4, 8, and 12 weeks postoperatively. Liver function tests and white blood cell count (WBC) were measured. Hematoxylin-eosin staining, cytokeratin 7 immunohistochemical staining, and Van Gieson's staining of EBD were used. The diameter and thickness of the EBD at the graft site were measured. There was no significant difference in liver function tests or WBC in the patch group compared with the control group. No evidence of leakage or stricture was observed, but some pigs developed biliary sludge or stone at 4 and 8 weeks. The drainage tube was lost within 12 weeks. The neo-EBD could withstand normal biliary pressure 2 weeks after surgery. Histological study showed the accessory glands and epithelial cells gradually regenerated at graft sites from 4 weeks, with increasing vessel infiltration and decreasing inflammation. The collagen fibers became regular with full coverage of epithelial cells. The statistical analysis of diameter and thickness showed no stricture formation at the graft site, but the EBD wall was slightly thicker than in the normal bile duct due to collagen fiber deposition. The structure of the neo-EBD was similar to that of the normal EBD. The collagen membrane patch associated with a drainage tube and wrapped with greater omentum effectively induced the regeneration of the EBD defect within 12 weeks.

Epithelial-mesenchymal transition-related protein expression in biliary epithelial cells associated with hepatolithiasis

BACKGROUND AND AIM

Epithelial-mesenchymal transition (EMT) of biliary epithelial cells (BECs) plays major roles in many cholangiopathies. This study evaluated whether EMT of BECs has a role in hepatolithiasis-induced biliary fibrosis and types of BECs that are involved.

METHODS

The expression of EMT-related proteins and epidermal growth factor receptor was evaluated by immunohistochemistry of liver tissues from 102 patients with hepatolithiasis, 32 patients with post-hepatitis cirrhosis, and 48 normal livers. Antibodies against E-cadherin, β-catenin, and cytokeratin were used to identify epithelial cells and antibodies against vimentin, S100A4, podoplanin, and α-smooth muscle actin (α-SMA) were used to identify mesenchymal cells. The relationship between clinical and histological parameters and immunohistochemistry findings in BECs, and the surrounding stroma were evaluated.

RESULTS

Loss of E-cadherin and acquisition of S100A4 and vimentin were observed in BECs. In all BECs, cytokeratin and β-catenin expression were unchanged, while podoplanin and α-SMA were not expressed. Although hepatic fibrosis was more severe in post-hepatitis cirrhosis, EMT of BECs was more widespread in hepatolithiasis. In hepatolithiasis, EMT-related proteins were more highly expressed in small bile ducts than in medium or large bile ducts. Their expression was associated with the severity of biliary fibrosis and the expressions of epidermal growth factor receptor. Expression of α-SMA in fibroblasts from the portal space was closely linked to pathological changes in small bile ducts and EMT-related protein expressions in BECs.

CONCLUSIONS

Proliferating cholangiocytes that form small bile ducts may contribute to cholangiopathies in hepatolithiasis through an EMT-like phenomenon or through interactions with stromal myofibroblasts.

Interest of a new biodegradable stent coated with paclitaxel on anastomotic wound healing after biliary reconstruction

OBJECTIVE

Benign biliary stricture of anastomotic stoma is frequent after biliary reconstruction. To prevent such a complication, a new paclitaxel-coated poly-L-lactide acid (PLLA) biodegradable biopolymer stent was designed. This original device was intended both to exert adequate mechanical support properties and to allow controlled drug delivery from the coating, with the goal of favoring wound healing after biliary reconstruction.

METHODS

PLLA stents coated with three different paclitaxel concentrations were implanted in the biliary anastomosis of mongrel dogs (defining groups B, C, and D, respectively). Dogs without stent placement were included in control group A. Liver function tests and residual dosage of paclitaxel from each stent were measured. Histological data and α-smooth muscle actin immunohistochemical staining of biliary-enteric anastomosis were examined.

RESULTS

There were no significant differences in liver function among the four groups and no bile leakage was observed. The paclitaxel-coated stents could slowly release paclitaxel for 9 weeks. In groups C and D, histological examinations showed less granulation tissue and glandular hyperplasia in biliary-enteric anastomosis than in control groups A and B. Submucosal collagen deposition was reduced and α-smooth muscle actin-positive cells decreased significantly, indicating the inhibition of myofibroblast proliferation in groups C and D.

CONCLUSION

PLLA-paclitaxel-coated stents reduced the proliferation of granulation tissue and glandular hyperplasia, and inhibited the myofibroblast proliferation and extracellular matrix overdeposition during the healing process of biliary-enteric anastomotic stoma. This original device may offer a new way for the prevention of benign biliary structure.

Tamoxifen decreases the myofibroblast count in the healing bile duct tissue of pigs

OBJECTIVE

The aim of this study was to evaluate the effect of oral tamoxifen treatment on the number of myofibroblasts present during the healing process after experimental bile duct injury.

METHODS

The sample consisted of 16 pigs that were divided into two groups (the control and study groups). Incisions and suturing of the bile ducts were performed in the two groups. Tamoxifen (20 mg/day) was administered only to the study group. The animals were sacrificed after 30 days. Quantification of myofibroblasts in the biliary ducts was made through immunohistochemistry analysis using anti-alpha smooth muscle actin of the smooth muscle antibody. Immunohistochemical quantification was performed using a digital image system.

RESULTS

In the animals treated with tamoxifen (20 mg/day), there was a significant reduction in immunostaining for alpha smooth muscle actin compared with the control group (0.1155 vs. 0.2021, p = 0.046).

CONCLUSION

Tamoxifen reduced the expression of alpha smooth muscle actin in the healing tissue after bile duct injury, suggesting a decrease in myofibroblasts in the scarred area of the pig biliary tract. These data suggest that tamoxifen could be used in the prevention of biliary tract stenosis after bile duct surgeries.

An end-to-end anastomosis model of guinea pig bile duct: A 6-mo observation

AIM: To establish the end-to-end anastomosis (EEA) model of guinea pig bile duct and evaluate the healing process of bile duct.

METHODS: Thirty-two male guinea pigs were randomly divided into control group, 2-, 3-, and 6-mo groups after establishment of EEA model. Histological, immunohistochemical and serologic tests as well as measurement of bile contents were performed. The bile duct diameter and the diameter ratio (DR) were measured to assess the formation of relative stricture.

RESULTS: Acute and chronic inflammatory reactions occurred throughout the healing process of bile duct. Serology test and bile content measurement showed no formation of persistent stricture in 6-mo group. The DR revealed a transient formation of relative stricture in 2-mo group in comparation to control group (2.94 ± 0.17 vs 1.89 ± 0.27, P = 0.004). However, this relative stricture was released in 6-mo group (2.14 ± 0.18, P = 0.440).

CONCLUSION: A simple and reliable EEA model of guinea pig bile duct can be established with a good reproducibility and a satisfactory survival rate.

Factors predicting failure following high bilio-enteric anastomosis for post-cholecystectomy benign biliary strictures

INTRODUCTION

Failures following Roux-en-Y hepatico-jejunostomy (HJ) for post-cholecystectomy benign bile duct strictures (BBS) pose significant challenge. This study was aimed to find out the factors predicting failure after surgical repair in patients with BBS.

METHODS

Between January 1989 and May 2007, 364 patients underwent Roux-en-Y HJ to the hilum for BBS. With a median follow-up of 61 (6-212) months, 334 (92%) patients had successful outcome and 30 (8%) had failure. A multivariate analysis was performed to find out the factors predicting failure.

RESULTS

Thirty patients who had failure became symptomatic after a median of 35 months (3 days-190 months) after surgical repair. Out of 30 patients, 11 (37%) were experiencing occasional episodes of cholangitis responding to antibiotics. All have patent anastomosis on nuclear scintigraphy and/or cholangiography. Cholangiogram demonstrated anastomotic stricture in 19/30 (63%) patients. Eighteen patients underwent re-intervention for re-strictures (nine--percutaneous balloon dilatation of the stricture, five--revision HJ, one--right hepatectomy, three--a combination of interventions). One patient refused to undergo a planned percutaneous balloon dilatation. Out of 18 patients, 12 (67%) had successful outcome following re-interventions. One patient who underwent revision HJ after a failed percutaneous balloon dilatation died in the immediate postoperative period. Preoperative bilirubin (p = 0.001), attempted bilio-enteric anastomosis before referral (0.004), cirrhosis (0.006), portal hypertension (p = 0.056), repair in the presence of external biliary fistula (0.000), and spontaneous bilio-enteric fistula (p = 0.011) were the factors found to be predicting failure of surgical repair on multivariate analysis.

CONCLUSIONS

Previous attempts of repair and delay in repair which predispose cirrhosis and portal hypertension may cause failure of surgical management in patients with BBS. In patients presenting with external biliary fistula, for a better outcome, surgical repair may be delayed till the fistula resolves.

Treatment of chronic proliferative cholangitis with c-myc shRNA

AIM: To investigate the feasibility and effectiveness of c-myc shRNA in inhibiting the hyperplastic behavior and lithogenic potentiality of chronic proliferative cholangitis (CPC), in order to prevent stone recurrence and biliary restenosis.

METHODS: An animal model of CPC was established by giving intralumenally 0.5 mL of c-myc shRNA. Then, the effects of c-myc shRNA on hyperplastic behavior and lithogenic potentiality of CPC were evaluated by histological observation, immunohistochemistry, real-time PCR and Western blotting for c-myc, proliferating cell nuclear antigen (PCNA), procollagen III, mucin 5AC, enzymatic histochemistry for β-glucuronidase, and biochemistry for hydroxyproline in the diseased bile duct.

RESULTS: Treatment with c-myc shRNA efficiently suppressed the hyperplasia of biliary epithelium, submucosal gland, and collagen fiber by inhibiting mRNA and protein expression of c-myc. More importantly, it decreased the lithogenic potentiality of CPC by inhibiting the expression of mucin 5AC and the secretion of endogenous β-glucuronidase. Further investigation indicated that c-myc shRNA-3 had a better inhibitory effect on CPC.

CONCLUSION: Treatment with c-myc shRNA-3 can control CPC and reduce the lithogenic potentiality of CPC.

Role of transforming growth factor-beta signaling pathway in pathogenesis of benign biliary stricture

AIM: To characterize the expression of members of the transforming growth factor-beta (TGF-β)/Smad/connective tissue growth factor (CTGF) signaling pathway in the tissue of benign biliary stricture, and to investigate the effect of TGF-β signaling pathway in the pathogenesis of benign biliary stricture.

METHODS: Paraffin embedded materials from 23 cases of benign biliary stricture were analyzed for members of the TGF-β/Smad/CTGF signaling pathway. TGF-β₁, TβRI, TβRII, Smad4, Smad7 and CTGF protein were detected by immunohistochemical strepto-advidinbiotin complex method, and CTGF mRNA was evaluated by hybridization in situ, while 6 cases of normal bile duct served as controls. The percentages of positive cells were counted. The correlation between TGF-β₁, Smad4 and CTGF was analyzed.

RESULTS: The positive expression ratios of TGF-β₁, TβRI, TβRII, Smad4, CTGF and CTGF mRNA in 23 cases with benign biliary stricture were 91.3%, 82.6%, 87.0%, 78.3%, 82.6% and 65.2%, respectively, significantly higher than that in 6 cases of normal bile duct respectively (vs 33.3%, 16.7%, 50.0%, 33.3%, 50.0%, 16.7%, respectively, P < 0.05). The positive expression ratio of Smad7 in cases with benign biliary stricture was 70.0%, higher than that in normal bile duct, but this difference is not statistically significant 70.0% vs 50%, P > 0.05). There was a positive correlation between positive expression of TGF-β₁, Smad4 and CTGF in cases with benign biliary stricture.

CONCLUSION: The high expression of TGF-β/Smad/CTGF signaling pathway plays an important role in the pathogenesis of benign biliary stricture.

Wound healing in the biliary tree of liver allografts

An increasing need for liver transplantation requires evaluation and triage of organs harvested from "extended criteria" donors. Although there is currently no widely accepted definition, most would agree that "extended criteria" includes organs donated by individuals that are old (>65 years), obese, infected with HBV or HCV, non-heart beating (NHBD), or had an unstable blood pressure before harvesting or the organ experienced a long cold ischemic time. These organs carry a statistical risk of dysfunction early after transplantation, but in the majority of recipients, hepatic parenchymal function recovers. Later, however, a small but significant percentage of extended criteria donors develop biliary strictures within several months after transplantation. The strictures occur primarily because of preservation injury that leads to "ischemic cholangitis" or deep wounding of the bile duct wall. Subsequent partial wound healing and wound contraction, but failed restitution of the biliary epithelial cell (BEC) lining, result in biliary tract strictures that cause progressive biliary fibrosis, increased morbidity, and decreased organ half-life. Better understanding of the pathophysiologic mechanisms that lead to biliary strictures in extended criteria donors provides an ideal proving ground for regenerative medicine; it also can provide insights into other diseases, such as extrahepatic biliary atresia and primary sclerosing cholangitis, that likely share certain pathogenic mechanisms. Possible points of therapeutic intervention include limiting cold and warm ischemic times, donor and/or donor organ treatment, ex vivo, to minimize the ischemic/preservation injury, maximize blood flow after transplantation, promote BEC wound healing, and limit myofibroblasts activation and proliferation in the bile duct wall. The pathobiology of biliary wound healing and therapeutic potential of interleukin-6 (IL-6) are highlighted.

Biliary wound healing, ductular reactions, and IL-6/gp130 signaling in the development of liver disease

Basic and translational wound healing research in the biliary tree lag significantly behind similar studies on the skin and gastrointestinal tract. This is at least partly attributable to lack of easy access to the biliary tract for study. But clinical relevance, more interest in biliary epithelial cell (BEC) pathophysiology, and widespread availability of BEC cultures are factors reversing this trend. In the extra-hepatic biliary tree, ineffectual wound healing, scarring and stricture development are pressing issues. In the smallest intra-hepatic bile ducts either impaired BEC proliferation or an exuberant response can contribute to liver disease. Chronic inflammation and persistent wound healing reactions in large and small bile ducts often lead to liver cancer. General concepts of wound healing as they apply to the biliary tract, importance of cellular processes dependent on IL-6/gp130/STAT3 signaling pathways, unanswered questions, and future directions are discussed.