A bioengineered artificial interstitium supports long-term islet xenograft survival in nonhuman primates without immunosuppression.

Cell-based therapies hold promise for many chronic conditions; however, the continued need for immunosuppression along with challenges in replacing cells to improve durability or retrieving cells for safety are major obstacles. We subcutaneously implanted a device engineered to exploit the innate transcapillary hydrostatic and colloid osmotic pressure generating ultrafiltrate to mimic interstitium. Long-term stable accumulation of ultrafiltrate was achieved in both rodents and nonhuman primates (NHPs) that was chemically similar to serum and achieved capillary blood oxygen concentration. The majority of adult pig islet grafts transplanted in non-immunosuppressed NHPs resulted in xenograft survival >100 days. Stable cytokine levels, normal neutrophil to lymphocyte ratio, and a lack of immune cell infiltration demonstrated successful immunoprotection and averted typical systemic changes related to xenograft transplant, especially inflammation. This approach eliminates the need for immunosuppression and permits percutaneous access for loading, reloading, biopsy, and recovery to de-risk the use of "unlimited" xenogeneic cell sources to realize widespread clinical translation of cell-based therapies.

Technical Considerations and Approach to Redo Foregut Surgery.

Foregut surgical techniques have advanced significantly over the years and have become increasingly popular. However, new challenges and technical considerations have arisen when dealing with reoperation for complications or surgical failure. This study focuses on the technical considerations and approach when dealing with reoperative foregut surgery, particularly redo hiatal hernia repair. We describe our approach starting from the preoperative workup to the procedural steps of the surgery. The present study describes the main steps for robotic reoperative hiatal hernia repair in a patient who had previously undergone laparoscopic hiatal hernia repair with Nissen fundoplication but did not present a recurrence of reflux and dysphagia symptoms. The patient is positioned supine with arms out and a footboard for steep Trendelenburg. We place six trocars, including an assistant port and a liver retractor port, to facilitate visualization and retraction. After docking the robot, we use a combination of electrocautery and sharp dissection to free the hernia sac and reduce the hiatal hernia. The previous fundoplication is then taken down carefully and the esophagus is mobilized through a transhiatal approach with a combination of blunt and sharp dissection until at least 3 cm of intra-abdominal esophageal length is achieved, after which a leak test is performed. We then perform a crural repair to reapproximate the hiatus with two posterior stitches and one anterior stitch. Lastly, a redo Nissen fundoplication is performed over a bougie, and endoscopy is used to confirm a loose stack-of-coin appearance. By emphasizing the crucial steps of redo hiatal hernia repair, including preoperative evaluation, our goal is to provide an approach for the foregut surgeon to maximize patient outcomes.

Suture Tape With Broad Full-Width Core Versus Traditional Round Suture With Round Core: A Mechanical Comparison.

PURPOSE: To compare the inherent mechanical properties of suture in tape configuration with a flat, evenly distributed core to a round suture with a round core composed of the same materials. METHODS: SutureTape and FiberWire composed of equivalent materials were used to tie surgical knots. Knot height was measured. Knot security was measured at the maximum load at 1, 2, and 3 mm of displacement and at failure. Tensile strength and stiffness were measured using untied samples. RESULTS: SutureTape demonstrated superior knot security with greater ultimate load to failure (327.2 ± 15.4 N vs 257.4 ± 12.2 N; P = .002), maximum load at 1 mm of displacement (149.8 ± 18.6 N vs 108.8 ± 13.8 N; P = .001), and 2 mm of displacement (242.7 ± 38.6 N vs 181.2 ± 24.4 N; P = .008). It also demonstrated greater stiffness (5.4 ± 0.3 N/mm vs 2.8 ± 0.3 N/mm; P < .001) and tensile strength (378.8 ± 13.6 N vs 235.6 ± 4.8 N). Knot height differences (1.27 ± .11 mm vs 1.37 ± .08 mm; P = .110) and load at 3 mm of displacement (279.3 ± 42.4 N vs 225.5 ± 46.1 N; P = .062) were not statistically significant. CONCLUSIONS: During mechanical testing, SutureTape with a broad core distributed over the full width of the tape demonstrated greater knot security, ultimate load to failure, and tensile stiffness than FiberWire, a round core suture. We found no significant difference in knot stack height between the suture designs. CLINICAL RELEVANCE: The study demonstrates the superior mechanical properties of suture in tape configuration over similarly composed round suture without a significant difference in knot stack height. Suture in tape configuration has the potential to perform as well as round suture in the clinical setting.