Liver specification of human iPSC-derived endothelial cells transplanted into mouse liver.

Background & Aims: Liver sinusoidal endothelial cells (LSECs) are important in liver development, regeneration, and pathophysiology, but the differentiation process underlying their tissue-specific phenotype is poorly understood and difficult to study because primary human cells are scarce. The aim of this study was to use human induced pluripotent stem cell (hiPSC)-derived LSEC-like cells to investigate the differentiation process of LSECs. Methods: hiPSC-derived endothelial cells (iECs) were transplanted into the livers of Fah-/-/Rag2-/-/Il2rg-/- mice and assessed over a 12-week period. Lineage tracing, immunofluorescence, flow cytometry, plasma human factor VIII measurement, and bulk and single cell transcriptomic analysis were used to assess the molecular and functional changes that occurred following transplantation. Results: Progressive and long-term repopulation of the liver vasculature occurred as iECs expanded along the sinusoids between hepatocytes and increasingly produced human factor VIII, indicating differentiation into LSEC-like cells. To chart the developmental profile associated with LSEC specification, the bulk transcriptomes of transplanted cells between 1 and 12 weeks after transplantation were compared against primary human adult LSECs. This demonstrated a chronological increase in LSEC markers, LSEC differentiation pathways, and zonation. Bulk transcriptome analysis suggested that the transcription factors NOTCH1, GATA4, and FOS have a central role in LSEC specification, interacting with a network of 27 transcription factors. Novel markers associated with this process included EMCN and CLEC14A. Additionally, single cell transcriptomic analysis demonstrated that transplanted iECs at 4 weeks contained zonal subpopulations with a region-specific phenotype. Conclusions: Collectively, this study confirms that hiPSCs can adopt LSEC-like features and provides insight into LSEC specification. This humanised xenograft system can be applied to further interrogate LSEC developmental biology and pathophysiology, bypassing current logistical obstacles associated with primary human LSECs. Impact and implications: Liver sinusoidal endothelial cells (LSECs) are important cells for liver biology, but better model systems are required to study them. We present a pluripotent stem cell xenografting model that produces human LSEC-like cells. A detailed and longitudinal transcriptomic analysis of the development of LSEC-like cells is included, which will guide future studies to interrogate LSEC biology and produce LSEC-like cells that could be used for regenerative medicine.

The incidence of symptomatic remnant gall bladder: a population study.

BACKGROUND: Subtotal cholecystectomy is utilized in conditions of high risk to critical structures, like the common bile duct. However, the remnant gall bladder may become symptomatic and require a completion cholecystectomy for treatment. This second procedure can itself be a risk to critical structures. To establish the incidence of redo-cholecystectomy and identify risk factors that lead to subtotal cholecystectomy and repeat operation in a review of state-based practices for cholecystectomy. METHODS: A search of state coding records relating to cholecystectomy from 1998 to 2016. Patients who were coded for cholecystectomy-related procedures on different dates were identified. Patients who underwent the procedures within 6 months were excluded to avoid acute post-operative complications and gall bladder malignancy. RESULTS: 210 719 cholecystectomies were performed. 1133 required repeat procedure. 616 were excluded, leaving 516 (0.25%) cholecystectomy patients requiring a second cholecystectomy. The subsequent operation was more likely to be an emergency procedure; involve transcystic bile duct exploration, adhesiolysis and require intensive care unit admission post-operatively. A repeat cholecystectomy was more likely to occur after having the primary procedure at a public hospital and when an intra-operative cholangiogram was not performed. Over the study period, the rate of repeat cholecystectomy increased from 0.02% to 0.6%. Incidentally, the rate of intra-operative cholangiogram during a primary cholecystectomy increased from 43% to 73%. CONCLUSIONS: Repeat cholecystectomy is an uncommon procedure. A second cholecystectomy is a more complex and likely to require intensive care unit support. Referral to a tertiary hepatobiliary unit is recommended.

Endoscopic management of post-cholecystectomy biliary fistula.

OBJECTIVE: Bile duct injury is an uncommon but potentially serious complication in cholecystectomy. A recognized treatment for minor biliary injury is internal biliary decompression by endoscopic retrograde cholangiopancreatography (ERCP) and stent insertion. The aim of this study was to assess the effectiveness of ERCP in the management of minor biliary injuries. METHODS: A retrospective review of medical records at a tertiary referral centre identified 36 patients treated for postoperative minor biliary injuries between 2006 and 2010. Management involved establishing a controlled biliary fistula followed by ERCP to confirm the nature of the injury and decompress the bile duct with stent insertion. RESULTS: Controlled biliary fistulae were established in all 36 patients. Resolution of the bile leak was achieved prior to ERCP in seven patients, and ERCP with stent insertion was successful in 27 of the remaining 29 patients. Resolution of the bile leak was achieved in all patients without further intervention. The median time to resolution after successful ERCP was 4 days. Two patients underwent ERCP complicated by mild pancreatitis. No other complications were seen. CONCLUSIONS: This review confirms that postoperative minor biliary injuries can be managed by sepsis control and semi-urgent endoscopic biliary decompression.

Endoscopic management of recurrent primary bile duct stones.

BACKGROUND: The management of recurrent choledocholithiasis today remains as challenging as in the pre-endoscopic era. Between 2 and 7% of affected patients have historically required surgical intervention for the treatment of recurrent or retained choledocholithiasis and of these, as many as 24% develop biliary complications. To avoid surgery, repeated endoscopic management of the problem has been suggested. In this study, we evaluate our policy of repeated endoscopic management of recurrent primary bile duct stones. METHODS: This study examined a cohort of nine patients identified from a prospective database with recurrent choledocholithiasis. Demographic, clinical and investigative details were recorded and data were analysed. Complications were determined from a review of the patient's file. RESULTS: There were nine patients and 66 procedures were carried out. Mean age at time of first endoscopy was 70.1 years (36-91 years). Three patients were of male sex (33.3%). The mean number of endoscopies carried out per patient was 7.3 (3-13). Failure to completely clear the duct occurred in 36.4% of all endoscopies. There were no periprocedural complications. CONCLUSION: Repeated endoscopic stone extraction by endoscopic retrograde cholangiopancreatography when required is a safe policy. However, this technique will only provide temporary relief from primary duct stones and repeated endoscopic treatment, again safe, will be required.

Pancreatic cancer - current management.

BACKGROUND: Pancreatic cancer remains a common and lethal cancer with a median survival of approximately 6 months. OBJECTIVE: This article discusses the current management of pancreatic cancer, both potentially curative and palliative treatment. DISCUSSION: Surgical resection of the primary tumour is only possible in about 10% of cases as many patients have locally advanced or metastatic disease at the time of presentation. For the majority of patients, treatment is palliative and may include surgical treatments or endoscopic or percutaneous stenting to relieve obstructive jaundice or gastric obstruction, chemotherapy, radiotherapy or interventional radiological techniques. Adequate pain relief and treatment of pancreatic insufficiency are important components of treatment.

Percutaneous cholecystostomy in the management of acute cholecystitis.

BACKGROUND: Percutaneous cholecystostomy (PC) has been used in managing acute cholecystitis in the setting of a patient with severe comorbidities where emergency cholecystectomy would carry significant mortality. The present study aims to assess the role, efficacy and complications of PC in acute cholecystitis. METHODS: Retrospective review of case notes of patients who underwent PC at Box Hill Hospital, Melbourne, Australia between July 1997 and December 2002. RESULTS: Sixteen patients (mean age 75 years; range 50-96) underwent PC. Indications for PC were significant comorbidities (n = 6), failure of conservative treatment (n = 4), bile duct malignancy (n = 2), sepsis of unknown origin (n = 2), patient declined surgery (n = 1) and local perforation (n = 1). Technical success rate was 94%. Clinical response to PC was observed in 15 patients. Overall mortality was 18% (3/16) with one death caused by PC failure. Interval cholecystectomy was performed in seven patients (44%). CONCLUSIONS: Percutaneous cholecystostomy is a useful alternative means of treating non-resolving acute cholecystitis in circumstances where emergency surgery is hazardous. It also offers effective palliation in patients not suitable for subsequent surgery.

Laparoscopic adrenalectomy for phaeochromocytoma: with caution.

INTRODUCTION: Laparoscopic adrenalectomy is well described and many series include patients with phaeochromocytoma. Our aim was to establish whether laparoscopic adrenalectomy for phaeochromocytoma was a safe and feasible technique at our institution. METHODS: Patients requiring adrenalectomy were entered into a prospective database that included patient details, operative data, hormone excretion, tumour size, hospital stay and complications. All operations were performed under the supervision of a single surgeon. Analysis was performed for those patients with a diagnosis of phaeochromocytoma. RESULTS: Of 60 patients having laparoscopic adrenal surgery, 18 had phaeochromocytoma as the indication. Seventeen (89%) of 19 tumours in these 18 patients were successfully removed laparoscopically. Median operative time was 180 min (range 130-300 min) and this was significantly longer compared with other adrenal pathology. The median tumour size was 6 cm which was significantly larger than other adrenal tumours. Seven (38%) patients developed complications and median postoperative inpatient stay was 5 days (range 3-8 days). CONCLUSIONS: The postoperative stay was equivalent to other laparoscopic series and laparoscopic removal was successful in 89%. The laparoscopic approach to the adrenal gland in phaeochromocytoma is safe and effective treatment.

Recognition and management of biliary complications after laparoscopic cholecystectomy.

INTRODUCTION: Injuries to the extrahepatic biliary tree at laparoscopic cholecystectomy cause major morbidity and are a major source of litigation. Injuries are often diagnosed late, leading to further complications and decreasing the chance of a successful repair. METHODS: A prospective study was carried out of all patients with extrahepatic biliary injuries from cholecystectomy who were referred to the surgeons of the Universities of Melbourne Hepatobiliary Group between 1997 and 1999. RESULTS: Twenty-seven patients sustained biliary injuries to the extrahepatic biliary tree. Twenty patients (74%) had unrecognized injuries at the time of cholecystectomy. The median time to referral was 9 days. Only two of 11 operative cholangiograms were interpreted as showing a biliary injury. CONCLUSION: Biliary injuries are still occurring at laparoscopic cholecystectomy. Guidelines about the management of a suspected biliary injury are discussed. Clinical, radiological and pathological assessment should enable prompt diagnosis and management should be instituted early, preferably with the involvement of a hepatobiliary specialist.

Prospective assessment of magnetic resonance cholangiopancreatography for noninvasive imaging of the biliary tree.

BACKGROUND: Traditionally, ERCP has been the only reliable method for imaging the biliary tree, but it is invasive and carries a risk of complications. Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive method for imaging the biliary tree. The aim of this study was to prospectively assess the accuracy of MRCP in a large number of patients. METHODS: Consecutive patients referred to a teaching hospital for ERCP were eligible for study entry. MRCP was performed within 24 hours before ERCP. MRCP findings were compared with ERCP findings or, when the initial ERCP was unsuccessful, with results of repeat ERCP, percutaneous transhepatic cholangiography, or surgery. RESULTS: One hundred forty-six patients underwent 149 ERCP/MRCP procedures, of which 129 were evaluable with successful MRCP and ERCP or an ERCP-equivalent study. Diagnoses included choledocholithiasis in 46 and biliary stricture in 12 patients. The sensitivity, specificity, positive, and negative predictive values for MRCP in the diagnosis of choledocholithiasis were 97.9%, 89.0%, 83.6%, and 98.6%, respectively. All 12 strictures were diagnosed by MRCP (sensitivity 100%, specificity 99.1%). CONCLUSIONS: MRCP is an accurate, noninvasive alternative to ERCP for imaging the biliary tree. Choledocholithiasis and biliary strictures can be reliably diagnosed or excluded by MRCP. MRCP should be used increasingly in patients with suspected biliary obstruction to select those who require a therapeutic procedure.