Device-assisted enteroscopy performance measures in the United Kingdom: DEEP-UK quality improvement project.

BACKGROUND: Device-assisted enteroscopy (DAE) has become a well-established diagnostic and therapeutic tool for the management of small-bowel pathology. We aimed to evaluate the performance measures for DAE across the UK against the quality benchmarks proposed by the European Society of Gastrointestinal Endoscopy (ESGE). METHODS: We retrospectively collected data on patient demographics and DAE performance measures from electronic endoscopy records of consecutive patients who underwent DAE for diagnostic and therapeutic purposes across 12 enteroscopy centers in the UK between January 2017 and December 2022. RESULTS: A total of 2005 DAE procedures were performed in 1663 patients (median age 60 years; 53% men). Almost all procedures (98.1%) were performed for appropriate indications. Double-balloon enteroscopy was used for most procedures (82.0%), followed by single-balloon enteroscopy (17.2%) and spiral enteroscopy (0.7%). The estimated depth of insertion was documented in 73.4% of procedures. The overall diagnostic yield was 70.0%. Therapeutic interventions were performed in 42.6% of procedures, with a success rate of 96.6%. Overall, 78.0% of detected lesions were marked with a tattoo. Patient comfort was significantly better with the use of deep sedation compared with conscious sedation (99.7% vs. 68.5%; P<0.001). Major adverse events occurred in only 0.6% of procedures. CONCLUSIONS: Performance measures for DAE in the UK meet the ESGE quality benchmarks, with high diagnostic and therapeutic yields, and a low incidence of major adverse events. However, there is room for improvement in optimizing sedation practices, standardizing the depth of insertion documentation, and adopting marking techniques to aid in the follow-up of detected lesions.

Long-term follow-up in patients with gastric antral vascular ectasia (GAVE) after treatment with endoscopic band ligation (EBL).

Background and study aims Gastric antral vascular ectasia (GAVE) is a capillary-type vascular malformation of the gastric antrum, usually diagnosed endoscopically in patients presenting with iron deficiency anemia or gastrointestinal bleeding. While there is established evidence for treatment with thermal modalities, such as argon plasma coagulation (APC) therapy, more recent studies have shown endoscopic band ligation (EBL) to be safe and effective in achieving remission. Our study aimed to evaluate long-term outcomes of patients with GAVE who underwent EBL at our institution. Patients and methods We retrospectively reviewed data from 33 patients with GAVE who underwent esophagogastroduodenoscopy and EBL between September 2012 and July 2017 within our institution, looking primarily at clinical response, recurrence, and blood transfusion requirements. Results Clinical response was achieved in 27 patients (81.8%). Among responders, recurrence-free survival decreased with time from 88 % at 1 year to 44 % at 2 years. Thirteen patients (48.1 %) had recurrence of GAVE at a mean time of 18.2 months (range 4.7 - 51.8). The only predictor of recurrence was greater number of pre-procedure blood transfusions. Conclusion This is the first study to evaluate long-term response and recurrence in patients with GAVE after treatment with EBL and predictors of clinical response after initial endoscopic therapy have been identified. While we were able to demonstrate excellent remission achievement rates in our GAVE patients who had undergone EBL, close clinical follow-up is clearly required as almost 50 % will have recurrence at around 18 months.

Pancreatic pseudocyst-portal vein fistula with refractory hepatic pseudocyst: Two cases treated with EUS cyst-gastrostomy and review of the literature.

Background and study aims Pseudocysts are the most common pancreatic cystic lesions and they usually develop in association with pancreatitis of at least 4 weeks' duration. Extra-pancreatic pseudocysts, although reported, are relatively uncommon. Secondary liver pseudocysts are recognized within the literature, and most patients described have required percutaneous or surgical drainage due to infection or symptoms. The mechanism of hepatic pseudocyst formation is not entirely clear but it is postulated that this phenomenon may occur through pseudocyst-portal vein fistulization. We describe two cases of patients presenting with pancreatic pseudocysts invading the portal venous system with embolization of pancreatic fluid to the liver and subsequent hepatic pseudocyst formation. Interestingly, liver pseudocyst resolution was incomplete with antibiotics and percutaneous drainage alone, and only occurred following endoscopic ultrasonography-guided pancreatic cyst-gastrostomy and metal stent insertion. We have reviewed the current literature on the diagnosis and management of pseudocyst-portal vein fistula formation and we believe that our cases represent the first published within the literature to describe this treatment approach.

Single-operator cholangioscopy for diagnosis of cholangioadenoma (bile duct adenoma) and its potential impact on surgical management.

Background and study aims Cholangioadenoma is not recognized commonly and is often only diagnosed on surgical specimens. Direct per oral single-operator cholangioscopy (SOC) allows characterization of common bile duct (CBD) lesions through direct visualization and directed forceps biopsies with potential for impacting surgical management decisions. This is a retrospective review of all SOC cases diagnosed with cholangioadenoma. Patient demographics and outcomes were recorded. Three patients (all male), average age 68 years (range 62 - 76 years), were identified to have a cholangioadenoma. The clinical indication for SOC was deranged liver enzymes with a dilated CBD and a CBD abnormality identified on biliary imaging. The site of cholangioadenoma was proximal, mid and distal CBD, respectively. All patients had a successful SOC with targeted biopsy-proven diagnosis. One patient had a synchronous cholangiocarcinoma and underwent palliative stenting whereas the other two patients underwent appropriate curative resection based on cholangioadenoma location. We conclude that SOC is safe and effective for diagnosis of cholangioadenoma and has potential impact on decisions for surgical management.

Boronate-containing polymer brushes: characterization, interaction with saccharides and mammalian cancer cells.

Boronate-containing polymer brushes were synthesized by free radical copolymerization of N,N-dimethylacrylamide (DMAA) and N-acryloyl-m-phenylboronic acid (NAAPBA) (9:1) on the surface of 3-mercaptopropyl-silylated glass plates and capillaries. The brushes were characterized with time-of-flight secondary ion mass-spectrometry (ToF SIMS), atomic force microscopy and contact angle measurements. Fructose caused a well-expressed drop spreading on the surface of copolymer-grafted glass, due to the strong interaction with the boronate groups. Sedimentation of murine hybridoma cells M2139 or human myeloid leukemia cells KG1 onto the DMAA-NAAPBA copolymer-grafted glass plates from 10 mM phosphate buffer solution (pH 8.0) resulted in the cell adhesion. The adhered M2139 and KG1 cells could be quantitatively detached from the grafted plates with 0.1 M fructose, which competed with cell surface carbohydrates for binding to the boronates. Evaluation of the binding strength between M2139 cells and the copolymer brush was performed by exposure of the adhered cells to a shear stress. Detachment of a fraction of 18% of the adhered M2139 cells was obtained at a shear force of 1400-2800 pN/cell generated by the running phosphate buffer (pH 8.0), whereas the remaining adhered cells (70%) could be detached with 0.1 M fructose dissolved in the same buffer. Possible applications of the boronate-containing polymer brushes to affinity cell separation can be based upon the facile recovery of the attached cells.

Blood-brain barrier traversal by African trypanosomes requires calcium signaling induced by parasite cysteine protease.

In this study we investigated why bloodstream forms of Trypanosoma brucei gambiense cross human brain microvascular endothelial cells (BMECs), a human blood-brain barrier (BBB) model system, at much greater efficiency than do T. b. brucei. After noting that T. b. gambiense displayed higher levels of cathepsin L-like cysteine proteases, we investigated whether these enzymes contribute to parasite crossing. First, we found that T. b. gambiense crossing of human BMECs was abrogated by N-methylpiperazine-urea-Phe-homopheylalanine-vinylsulfone-benzene (K11777), an irreversible inhibitor of cathepsin L-like cysteine proteases. Affinity labeling and immunochemical studies characterized brucipain as the K11777-sensitive cysteine protease expressed at higher levels by T. b. gambiense. K11777-treated T. b. gambiense failed to elicit calcium fluxes in BMECs, suggesting that generation of activation signals for the BBB is critically dependant on brucipain activity. Strikingly, crossing of T. b. brucei across the BBB was enhanced upon incubation with brucipain-rich supernatants derived from T. b. gambiense. The effects of the conditioned medium, which correlated with ability to evoke calcium fluxes, were canceled by K11777, but not by the cathepsin B inhibitor CA074. Collectively, these in vitro studies implicate brucipain as a critical driver of T. b. gambiense transendothelial migration of the human BBB.

African trypanosome interactions with an in vitro model of the human blood-brain barrier.

The neurological manifestations of sleeping sickness in man are attributed to the penetration of the blood-brain barrier (BBB) and invasion of the central nervous system by Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. However, how African trypanosomes cross the BBB remains an unresolved issue. We have examined the traversal of African trypanosomes across the human BBB using an in vitro BBB model system constructed of human brain microvascular endothelial cells (BMECs) grown on Costar Transwell inserts. Human-infective T. b. gambiense strain IL 1852 was found to cross human BMECs far more readily than the animal-infective Trypanosoma brucei brucei strains 427 and TREU 927. Tsetse fly-infective procyclic trypomastigotes did not cross the human BMECs either alone or when coincubated with bloodstreamform T. b. gambiense. After overnight incubation, the integrity of the human BMEC monolayer measured by transendothelial electrical resistance was maintained on the inserts relative to the controls when the endothelial cells were incubated with T. b. brucei. However, decreases in electrical resistance were observed when the BMEC-coated inserts were incubated with T. b. gambiense. Light and electron microscopy studies revealed that T. b. gambiense initially bind at or near intercellular junctions before crossing the BBB paracellularly. This is the first demonstration of paracellular traversal of African trypanosomes across the BBB. Further studies are required to determine the mechanism of BBB traversal by these parasites at the cellular and molecular level.

Trypanosome hydrolases and the blood-brain barrier.

African trypanosomes cross the blood-brain barrier, but how they do so remains an area of speculation. We propose that proteases, such as the trypanopains and oligopeptidases that are released by trypanosomes, could mediate in this process. The trypanosomes also possess cell-surface-associated acid phosphatases that could play a role in invasion similar to that in advancing cancer cells. Such enzymes, perhaps acting in concert, have the potential to cause tissue degradation and ease the passage of the trypanosomes through various tissues in the host, including the blood-brain barrier.