Molecular profiling of visible polypoid and invisible conventional intestinal-type low-grade dysplasia in patients with idiopathic inflammatory bowel disease.

AIMS: Little is known about the molecular features of visible polyps with low-grade intestinal-type dysplasia in patients with inflammatory bowel disease (IBD). To better understand their origins and biological potential, we sought to genomically profile these lesions and compare them with invisible low-grade dysplasia and sporadic adenomas from non-IBD patients. METHODS: 22 polyps within areas of colitis, 13 polyps outside areas of colitis, 10 foci of invisible dysplasia from patients with IBD and 6 sporadic tubular adenomas from non-IBD patients were analysed using the OncoPanel assay. RESULTS: Polyps arising in areas of colitis showed a greater spectrum of mutations, including APC, KRAS, FBXW7, TP53, ARID1A and TCF7L2. Polyps outside colitis and non-IBD sporadic adenomas showed a limited mutational profile, with APC and CTNNB1 mutations. Invisible dysplasia was characterised by TP53, CTNNB1 and KRAS alterations. Compared with dysplastic polyps, none of the invisible dysplastic foci showed APC alterations (73%-within colitis; p=0.0001, 92%-outside colitis; p<0.0001, 83%-sporadic adenomas; p=0.001). TP53 mutations were significantly higher in invisible dysplasia (50%) compared with polyps within colitis (9%; p=0.02) and outside colitis (8%; p=0.03). CONCLUSIONS: Molecular alterations in visible low-grade dysplastic polyps with conventional intestinal-type dysplasia from patients with IBD and sporadic adenomas from non-IBD patients overlap significantly. APC alterations appear to play a major role in the development of visible low-grade dysplastic lesions in patients with IBD, regardless of background colitis. As with IBD-associated colorectal cancers, TP53 mutations are an early event in the development of invisible, low-grade conventional intestinal-type dysplasia in patients with IBD.

Targeted Cancer Next-Generation Sequencing as a Primary Screening Tool for Microsatellite Instability and Lynch Syndrome in Upper Gastrointestinal Tract Cancers.

BACKGROUND: No consensus guideline has been established for microsatellite instability testing in upper gastrointestinal tract cancers. This study aims to determine whether targeted cancer next-generation sequencing can accurately detect microsatellite instability in upper gastrointestinal tract cancers and screen for patients with Lynch syndrome. METHODS: In a cohort of 645 upper gastrointestinal tract cancers, targeted next-generation sequencing assessed microsatellite instability by identifying characteristic insertion and deletion mutations. Sequencing classification was compared with mismatch repair protein IHC. Cancers with microsatellite instability by sequencing were analyzed using a testing protocol to identify patients with Lynch syndrome. RESULTS: Sequencing identified microsatellite instability in 3.6% (23/645) of upper gastrointestinal tract cancers, including 28% (8/29) of small intestinal and 9% (9/97) of gastric carcinomas. In 20 cancers classified as having microsatellite instability, 19 demonstrated loss of expression of MLH1, PMS2, MSH2, or MSH6, and one cancer was indeterminate by IHC. In contrast, 52 control cancers demonstrated retained expression of all mismatch repair proteins. Using targeted sequencing as the initial screening test, 1.1% (7/645) of patients were identified to have pathogenic germline variants confirming a diagnosis of Lynch syndrome. CONCLUSIONS: Targeted cancer next-generation sequencing is an accurate first-line test to detect microsatellite instability in upper gastrointestinal tract cancers. IMPACT: This study provides a proof of concept for the use of targeted next-generation sequencing to detect microsatellite instability and screen for Lynch syndrome.

Thrombus on the inflow cannula of the HeartWare HVAD: an update.

BACKGROUND: The HeartWare HVAD (Medtronic, Minneapolis, MN) is a continuous-flow left ventricular assist device (LVAD) approved by the FDA in 2012 as a bridge to transplant in patients with end-stage left ventricular heart failure. The current inflow cannula has a smooth outer surface near the inflow edge and a sintered collar of titanium microspheres near the pump. A previous case series of HVAD patients bridged to transplant revealed thrombus on the outer surface of the inflow cannula in 8 of 8 patients, predominantly at the smooth-sintered interface, that was associated with a clinical stroke rate of 12.5%. DESIGN: Cases of HVAD devices removed at the time of heart transplant were identified in the surgical pathology database. The gross and microscopic findings were reviewed along with clinical data. RESULTS: A total of 22 patients with 24 HVAD implants diagnosed with dilated cardiomyopathy (13 patients), ischemic heart disease (4 patients), lymphocytic myocarditis (2 patients), hypertrophic cardiomyopathy (2 patients), and congenital valvular disease (1 patient) were included. Two patients received two HVADs to provide biventricular support. All patients received post-implantation anti-coagulation with an INR goal of 2 to 3. Gross pathologic examination revealed thrombi on the outer aspect of the HVAD inflow cannula in 23 of 24 devices (96%). The inflow cannula of the one device that did not develop thrombus was positioned such that the smooth-sintered interface was buried in the ventricular myocardium and not in contact with blood in the ventricular chamber. Complications during the period of device support included 9 thromboembolic events (41%) including 6 ischemic strokes (27%), 2 intracoronary thromboembolic events and 1 splenic infarct. Patients suffered strokes 4 to 174 days (mean 82) after HVAD placement and had thrombus on the inflow cannula ranging in size from 0.1-2.5 cm (axial), 0.4-4.5 cm (circumferential) and 0.1-0.5 cm (thickness). Histologic evaluation revealed bland, partially organized thrombi without evidence of infection. Other complications included driveline infections (9%), non-driveline related bacteremia (9%) and hemorrhage (5%). CONCLUSIONS: We report here an extension of our original study to a total of 22 patients with 24 HVAD implants who were all successfully bridged to transplant. We validate the very high prevalence of thrombus around the HVAD inflow cannula, associated with a clinical thromboembolic event in over a third of the patients, the majority of which were strokes. The nidus for thrombus formation appears to be the smooth-sintered interface of the HVAD inflow cannula.

Engineered vascular tissue fabricated from aggregated smooth muscle cells.

The goal of this study was to develop a system to rapidly generate engineered tissue constructs from aggregated cells and cell-derived extracellular matrix (ECM) to enable evaluation of cell-derived tissue structure and function. Rat aortic smooth muscle cells seeded into annular agarose wells (2, 4 or 6 mm inside diameter) aggregated and formed thick tissue rings within 2 weeks of static culture (0.76 mm at 8 days; 0.94 mm at 14 days). Overall, cells appeared healthy and surrounded by ECM comprised of glycosoaminoglycans and collagen, although signs of necrosis were observed near the centers of the thickest rings. Tissue ring strength and stiffness values were superior to those reported for engineered tissue constructs cultured for comparable times. The strength (100-500 kPa) and modulus (0.5-2 MPa) of tissue rings increased with ring size and decreased with culture duration. Finally, tissue rings cultured for 7 days on silicone mandrels fused to form tubular constructs. Ring margins were visible after 7 days, but tubes were cohesive and mechanically stable, and histological examination confirmed fusion between ring subunits. This unique system provides a versatile new tool for optimization and functional assessment of cell-derived tissue, and a new approach to creating tissue-engineered vascular grafts.