Therapeutic application of decellularized porcine small intestinal submucosa scaffold in conjunctiva reconstruction.

The objective of this study was to investigate the biological feasibility and surgical applicability of decellularized porcine small intestinal submucosa (DSIS) in conjunctiva reconstruction. A total of 52 Balb/c mice were included in the study. We obtained the DSIS by decellularization, evaluated the physical and biological properties of DSIS in vitro, and further evaluated the effect of surgical transplantation of DSIS scaffold in vivo. The histopathology and ultrastructural analysis results showed that the scaffold retained the integrity of the fibrous morphology while removing cells. Biomechanical analysis showed that the elongation at break of the DSIS (239.00 ± 12.51%) were better than that of natural mouse conjunctiva (170.70 ± 9.41%, P < 0.05). Moreover, in vivo experiments confirmed the excellent biocompatibility of the decellularized scaffolds. In the DSIS group, partial epithelialization occurred at day-3 after operation, and the conjunctival injury healed at day-7, which was significantly faster than that in human amniotic membrane (AM) and sham surgery (SHAM) group (P < 0.05). The number and distribution of goblet cells of transplanted DSIS were significantly better than those of the AM and SHAM groups. Consequently, the DSIS scaffold shows excellent biological characteristics and surgical applicability in the mouse conjunctival defect model, and DSIS is expected to be an alternative scaffold for conjunctival reconstruction.

Small intestinal submucosa graft bulbar urethroplasty is a viable technique: results compared to buccal mucosa graft urethroplasty after propensity score matching.

PURPOSE: Small intestinal submucosa (SIS) graft urethroplasty has been employed to decrease buccal mucosa morbidity and facilitate the procedure. The first published series had a short follow-up, inhomogeneous patient selection, and a lack of a control group. Our purpose is to report treatment outcomes at 13 years in a propensity score-matched cohort comparing bulbar urethroplasty with SIS (SISU) or buccal mucosa (BMU). METHODS: From our institutional database of 1132 bulbar urethroplasties, we used propensity score matching with the nearest-neighbor method without replacement to generate a study sample of 25 BMU and 25 SISU. Failure was defined as any treatment after urethroplasty. Survival analyses were used to analyze treatment failure occurrence with data censored at 156mo. RESULTS: Matching resulted in a complete correction of bias between the two samples except for the follow-up duration, which was slightly longer in the SIS group. The cumulative treatment success probability of BMU and SISU at 156mo was 83.4% and 68%, respectively. At multivariable Cox regression, SIS graft, previous urethrotomy, stricture length, and lower postoperative Qmax (within 2mo after catheter removal) were predictors of failure. Stricture length had a more remarkable effect in SISU, with estimated survival probabilities from the Cox model lower than 80% in strictures > = 3 cm. CONCLUSION: SIS has poorer outcomes compared to BM but may still be useful when BM grafting is not possible. The best candidates for SISU, with similar success to BMU, are patients with strictures shorter than 3 cm, preferably without a history of DVIU.

Reinforcing decellularized small intestine submucosa with cellulose acetate nanofibrous and silver nanoparticles as a scaffold for wound healing applications.

BACKGROUND: The formation of chronic wounds accounts for considerable costs in health care systems. Despite the several benefits of decellularized small intestinal submucosa (SIS) as an appropriate scaffold for different tissue regeneration, it has shortcomings such as lack of antibacterial features and inappropriate mechanical properties for skin tissue regeneration. We aimed to examine the efficacy and safety of decellularized SIS scaffold enhanced with cellulose acetate (CA) and silver (Ag) nanoparticles (NPs) for healing full-thickness wounds. METHODS AND RESULTS: The scaffolds were prepared by decellularizing bovine SIS and electrospinning CA/Ag nanoparticles and characterized using a transmission electron microscope (TEM), scanning electron microscope (SEM), tensile testing, and X-ray diffraction. In vivo evaluations were performed using full-thickness excisions covered with sterile gauze as the control group, SIS, SIS/CA, and SIS/CA/Ag scaffolds on the dorsum of twenty male Wistar rats divided into four groups randomly with 21-days follow-up. All in vivo specimens underwent Masson's trichrome (MT) staining for evaluation of collagen deposition, transforming growth factor-ß (TGF-ß) immunohistochemistry (IHC), and Haematoxylin Eosin (H&E) staining. The IHC and MT data were analyzed with the ImageJ tool by measuring the stained area. The TEM results revealed that Ag nanoparticles are successfully incorporated into CA nanofibers. Assessment of scaffolds hydrophilicity demonstrated that the contact angle of SIS/CA/Ag scaffold was the lowest. The in vivo results indicated that the SIS/CA/Ag scaffold had the most significant wound closure. H&E staining of the in vivo specimens showed the formation of epidermal layers in the SIS/CA/Ag group on day 21. The percentage of the stained area of MT and TGF-ß IHC staining's was highest in the SIS/CA/Ag group. CONCLUSION: The decellularized SIS/CA/Ag scaffolds provided the most significant wound closure compared to other groups and caused the formation of epidermal layers and skin appendages. Additionally, the collagen deposition and expression of TGF-ß increased significantly in SIS/CA/Ag group.

Application of multi-layer porcine small intestinal submucosa for the reconstruction of deep corneal defects in cats.

OBJECTIVE: This study documented the application of porcine small intestinal submucosa (SIS) as a stand-alone scaffold for treating deep corneal defects in cats. METHODS: Medical records of 20 cats with deep stromal ulcers, perforations, or corneal sequestra that underwent surgical treatment with SIS grafts between 2021 and 2022 were retrospectively reviewed. Data on re-epithelialization time, corneal transparency score, and complications were collected to analyze the reconstruction of deep corneal defects after SIS biomaterial implantation. RESULTS: All cats were unilaterally affected. The corneal defects varied in size, with a median diameter of 8.3 mm (range: 3-15 mm). Re-epithelialization of the SIS graft was completed 16-32 days after surgery (median, 22.3 days). No, mild, or moderate corneal transparency was detected in 90% of the cases. Complications were observed in eight cases (40%), including aqueous leakage (10%), partial SIS malacia (25%), and persistent bullous keratopathy (5%). The follow-up period ranged 90-725 days, with a median duration of 255 days. The SIS graft was successfully applied as a single scaffold in 17 of 20 cases (85%). CONCLUSION: The results of this study suggest that the application of commercial SIS is an effective surgical technique for managing deep corneal defects in cats.

Multi-Omics Characterization of Colon Mucosa and Submucosa/Wall from Crohn's Disease Patients.

Crohn's disease (CD) is a subtype of inflammatory bowel disease (IBD) characterized by transmural disease. The concept of transmural healing (TH) has been proposed as an indicator of deep clinical remission of CD and as a predictor of favorable treatment endpoints. Understanding the pathophysiology involved in transmural disease is critical to achieving these endpoints. However, most studies have focused on the intestinal mucosa, overlooking the contribution of the intestinal wall in Crohn's disease. Multi-omics approaches have provided new avenues for exploring the pathogenesis of Crohn's disease and identifying potential biomarkers. We aimed to use transcriptomic and proteomic technologies to compare immune and mesenchymal cell profiles and pathways in the mucosal and submucosa/wall compartments to better understand chronic refractory disease elements to achieve transmural healing. The results revealed similarities and differences in gene and protein expression profiles, metabolic mechanisms, and immune and non-immune pathways between these two compartments. Additionally, the identification of protein isoforms highlights the complex molecular mechanisms underlying this disease, such as decreased RTN4 isoforms (RTN4B2 and RTN4C) in the submucosa/wall, which may be related to the dysregulation of enteric neural processes. These findings have the potential to inform the development of novel therapeutic strategies to achieve TH.

Implementation of esophageal endoscopic submucosal dissection in Spain: Results from the nationwide registry. / Implementación de la disección endoscópica submucosa esofágica en España: resultados del registro nacional.

INTRODUCTION AND AIMS: The outcomes of endoscopic submucosal dissection (ESD) in the esophagus have not been assessed in our country. Our primary aim was to analyze the effectiveness and safety of the technique. MATERIAL AND METHODS: Analysis of the prospectively maintained national registry of ESD. We included all superficial esophageal lesions removed by ESD in 17 hospitals (20 endoscopists) between January 2016 and December 2021. Subepithelial lesions were excluded. The primary outcome was curative resection. We conducted a survival analysis and used logistic regression analysis to assess predictors of non-curative resection. RESULTS: A total of 102 ESD were performed on 96 patients. The technical success rate was 100% and the percentage of en-bloc resection was 98%. The percentage of R0 and curative resection was 77.5% (n=79; 95%CI: 68%-84%) and 63.7% (n=65; 95%CI: 54%-72%), respectively. The most frequent histology was Barrett-related neoplasia (n=55 [53.9%]). The main reason for non-curative resection was deep submucosal invasion (n=25). The centers with a lower volume of ESD obtained worse results in terms of curative resection. The rate of perforation, delayed bleeding and post-procedural stenosis were 5%, 5% and 15.7%, respectively. No patient died or required surgery due to an adverse effect. After a median follow-up of 14months, 20patients (20.8%) underwent surgery and/or chemoradiotherapy, and 9 patients died (mortality 9.4%). CONCLUSIONS: In Spain, esophageal ESD is curative in approximately two out of three patients, with an acceptable risk of adverse events.

[Effects of different polymers on biomimetic mineralization of small intestine submucosal scaffolds].

OBJECTIVE: To explore the effects of different polymers on in vitro biomimetic mineralization of small intestinal submucosa (SIS) scaffolds, and to evaluate the physicochemical properties and biocompatibility of the SIS scaffolds. METHODS: The SIS scaffolds prepared by freeze-drying method were immersed in simulated body fluid (SBF), mineralized liquid containing polyacrylic acid (PAA) and mine-ralized liquid containing PAA and polyaspartic acid (PASP). After two weeks in the mineralized solution, the liquid was changed every other day. SBF@SIS, PAA@SIS, PAA/PASP@SIS scaffolds were obtained. The SIS scaffolds were used as control group to evaluate their physicochemical properties and biocompatibility. We observed the bulk morphology of the scaffolds in each group, analyzed the microscopic morphology by environment scanning electron microscopy and determined the porosity and pore size. We also analyzed the surface elements by energy dispersive X-ray spectroscopy (EDX), analyzed the structure of functional groups by Flourier transformed infrared spectroscopy (FTIR), detected the water absorption rate by using specific gravity method, and evaluated the compression strength by universal mechanical testing machine. The pro-cell proliferation effect of each group of scaffolds were evaluated by CCK-8 cell proliferation method. RESULTS: Under scanning electron microscopy, the scaffolds of each group showed a three-dimensional porous structure with suitable pore size and porosity, and crystal was observed in all the mineralized scaffolds of each group, in which the crystal deposition of PAA/PASP@SIS scaffolds was more regular. At the same time, the collagen fibers could be seen to thicken. EDX analysis showed that the characteristic peaks of Ca and P were found in the three groups of mineralized scaffolds, and the highest peaks were found in the PAA/PASP@SIS scaffolds. FTIR analysis proved that all the three groups of mineralized scaffolds were able to combine hydroxyapatite with SIS. All the scaffolds had good hydrophilicity. The compressive strength of the mineralized scaffold in the three groups was higher than that in the control group, and the best compressive strength was found in PAA/PASP@SIS scaffold. The scaffolds of all the groups could effectively adsorb proteins, and PAA/PASP@SIS group had the best adsorption capacity. In the CCK-8 cell proliferation experiment, the PAA/PASP@SIS scaffold showed the best ability to promote cell proliferation with the largest number of living cells observed. CONCLUSION: Compared with other mineralized scaffolds, PAA/PASP@SIS scaffolds prepared by mineralized solution containing both PAA and PASP have better physicochemical properties and biocompatibility and have potential applications in bone tissue engineering.

Mfge8 is expressed by pericytes in gastric antrum submucosa from patients with obesity.

The main function of the stomach is to digest ingested food. Gastric antrum muscular contractions mix ingested food with digestive enzymes and stomach acid and propel the chyme through the pyloric sphincter at a rate in which the small intestine can process the chyme for optimal nutrient absorption. Mfge8 binding to α8ß1 integrins helps regulate gastric emptying by reducing the force of antral smooth muscle contractions. The source of Mfge8 within gastric muscles is unclear. Since Mfge8 is a secreted protein, Mfge8 could be delivered via the circulation, or be locally secreted by cells within the muscle layers. In this study, we identify a source of Mfge8 within human gastric antrum muscles using spatial transcriptomic analysis. We show that Mfge8 is expressed in subpopulations of Mef2c+ perivascular cells within the submucosa layer of the gastric antrum. Mef2c is expressed in subpopulations of NG2+ and PDGFRB+ pericytes. Mfge8 is expressed in NG2+/Mef2c+ pericytes, but not in NG2+/Mef2c-, PDGFRB+/Mef2c-, or PDGFRB+/Mef2c+ pericytes. Mfge8 is absent from CD34+ endothelial cells but is expressed in a small population of perivascular ACTA2+ cells. We also show that α8 integrin is not expressed by interstitial cells of Cajal (ICC), supporting the findings that Mfge8 attenuates gastric antrum smooth muscle contractions by binding to α8ß1 integrins on enteric smooth muscle cells. These findings suggest a novel, supplementary mechanism of regulation of gastric antrum motility by cellular regulators of capillary blood flow, in addition to the regulation of gastric antrum motility by the enteric nervous system and the SMC, ICC, and PDGFRα+ cell (SIP) syncytium.

Optimization of decellularization methods using human small intestinal submucosa for scaffold generation in regenerative medicine.

Porcine small intestinal submucosa, despite its successful use as a scaffold in regenerative medicine, has innate biomechanical heterogeneity. In this study, we hypothesized that human small intestinal submucosa could be a viable alternative bio-scaffold. For the first time, we characterize submucosal extraction from human small intestine and examine appropriate decellularization methods. In total, 16 human small intestinal submucosal samples were obtained and decellularized using three reported methods of porcine decellularization: Abraham, Badylak, and Luo. For each method, four specimens were decellularized. The remaining four specimens were designated as non-decellularized. We measured the amount of residual DNA and growth factors in decellularized human intestinal samples. Additionally, decellularized human small intestinal submucosa was co-cultured with mouse bone marrow-derived mesenchymal stem cells to examine mesenchymal stem cell survival and proliferation. The reference value for the amount of residual DNA deemed appropriate in decellularized tissue was established as 50 ng/mg of extracellular matrix dry weight or less. Abraham's method most successfully met this criterion. Measurement of residual growth factors revealed low levels observed in samples decellularized using the Abraham and Badylak methods. Co-culture of each small intestinal submucosal sample with mouse bone marrow-derived mesenchymal stem cells confirmed viable cell survival and proliferation in samples derived using protocols by Abraham and Badylak. Abraham's method most successfully met the criteria for efficient tissue decellularization and cell viability and proliferation. Thus, we consider this method most suitable for decellularization of human small intestinal submucosa.

The long-term outcomes of vaginoplasty using acellular porcine small intestinal submucosa grafts in patients with Mayer-Rokitansky-Küster-Hauser syndrome: A case series.

OBJECTIVE: To investigate the long-term outcomes for Mayer-Rokitansky-Küster-Hauser syndrome (MRKH) patients undergoing vaginoplasty using acellular porcine small intestinal submucosa grafts (SIS). DESIGN: A case series. POPULATION: Seventy-eight MRKH syndrome patients and a post-SIS patient who delivered a baby following the world's first robot-assisted uterus transplantation. METHODS: Mayer-Rokitansky-Küster-Hauser syndrome patients were grouped based on the postoperative time and the diagnosis-surgery interval. Outcomes of sexual function and psychological status were assessed using the female sexual function index (FSFI), self-rating scale of body image (SSBI) and self-acceptance questionnaire (SAQ). Anatomical outcomes were measured by clinicians. MAIN OUTCOME MEASURES: The primary outcome was restoration of sexual function, defined by an FSFI score in the 'good' range. Anatomical and psychological outcomes were also analysed. RESULTS: Sexual function was restored in 42.3% (33/78) of patients and the total FSFI score was 23.44 ± 4.43. Three factors (body defect, recognition of physical appearance and willingness to change physical appearance scores) in the SSBI and two in the SAQ decreased as the postoperative time increased. Based on the interval between diagnosis and surgery, the total SSBI score was lower in the short-interval group than in the long-interval group (7.25 ± 5.55 versus 12.04 ± 10.21, p = 0.038). CONCLUSIONS: Nearly half of MRKH patients in our study had good long-term sexual function after SIS vaginoplasty. Sexual function and psychological status improved as postoperative time increased. In addition, reducing the diagnosis to surgery interval was associated with improved psychological function.

What role does the submucosa play in the pathophysiology and treatment of achalasia? An analysis of impedance planimetry during POEM.

BACKGROUND: It is thought the therapeutic benefit of per-oral endoscopic myotomy (POEM) in the treatment of esophageal dysmotility disorders is from longitudinal myotomy creation, but it is unknown if the submucosa contributes to the pathophysiology. This study investigates if submucosal tunnel (SMT) dissection alone contributes to POEM's luminal changes as measured by EndoFLIP. METHODS: A single-center, retrospective review of consecutive POEM cases from June 1, 2011 to September 1, 2022 with intraoperative luminal diameter and distensibility index (DI) data as measured by EndoFLIP. Patients with diagnoses of achalasia or esophagogastric junction outflow obstruction were grouped by those with pre-SMT and post-myotomy measurements (Group 1) and those with a third measurement post-SMT dissection (Group 2). Outcomes and EndoFLIP data were analyzed using descriptive and univariate statistics. RESULTS: There were 66 patients identified, of whom 57 (86.4%) had achalasia, 32 (48.5%) were female, and median pre-POEM Eckardt score was 7 [IQR: 6-9]. There were 42 (64%) patients in Group 1, and 24 (36%) patients in Group 2, with no differences in baseline characteristics. In Group 2, SMT dissection changed luminal diameter by 2.15 [IQR: 1.75-3.28]cm, which comprised 38% of the median 5.6 [IQR: 4.25-6.3]cm diameter of complete POEM change. Similarly, the median post-SMT change in DI of 1 [IQR: 0.5-1.2]units comprised 30% of the median 3.35 [2.4-3.98]units overall change in DI. Post-SMT diameters and DI were both significantly lower than the full POEM. CONCLUSIONS: Esophageal diameter and DI are significantly affected by SMT dissection alone, though not equaling the magnitude of diameter or DI changes from full POEM. This suggests that the submucosa does play a role in achalasia, presenting a future target for refining POEM and developing alternative treatment strategies.

Outcome of a novel porcine-derived UBM/SIS composite biological mesh in a rabbit vaginal defect model.

INTRODUCTION AND HYPOTHESIS: To investigate the tissue reactions of a novel porcine-derived urinary bladder matrix/small intestinal submucosa (UBM/SIS) biological mesh and SIS mesh implanted in a rabbit vaginal defect model. METHODS: Thirty-two rabbits were implanted with UBM/SIS mesh (Group A) and SIS mesh (Group B), respectively. Rabbits were sacrificed at 7, 14, 60, and 180 days after implantation. The tensile strength, elongation at break, and elastic modulus of the tissue were measured using biomechanical methods. The inflammatory response, cell infiltration, vascularization, and collagen fibers were observed. RESULTS: Compared with Group B, the tensile strength and elongation at break of group A was higher at 14, 60, and 180 days. The elastic modulus of group A was lower at 180 days. Inflammatory response of group A was milder at 14, 60, and 180 days. There was more cell infiltration in group A at 7 and 14 days. Vascularization was higher in group A at 7 days and 14 days. The order of collagen in group A was better at 14, 60, and 180 days. The proportion of thick red fibers in both groups showed an increasing trend. At 14 days, group A had more thick red fibers. CONCLUSIONS: The novel UBM/SIS composite mesh had a milder inflammatory response; earlier induction of cell infiltration, angiogenesis, and collagen regeneration. Collagen fibers had a better order. It has a higher tensile strength and greater elongation at break, and can be used as a potential material for the treatment of pelvic organ prolapse.

Comparison of Sheares vaginoplasty, vaginoplasty using acellular porcine small intestinal submucosa graft and laparoscopic peritoneal vaginoplasty in patients with Mayer-Rokitansky-Küster-Hauser syndrome.

INTRODUCTION AND HYPOTHESIS: The aim of this study is to compare the perioperative, anatomical and functional outcomes of patients with Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS), undergoing Sheares vaginoplasty, vaginoplasty using acellular porcine small intestinal submucosa (SIS) graft or laparoscopic peritoneal (Davydov) vaginoplasty. METHODS: In this retrospective study, a total of 117 patients with MRKHS undergoing creation of a neovagina from 2017 to 2020 were retrospectively investigated. Comparisons between continuous variables were performed using Student's t-test and between qualitative variables using chi-squared tests. RESULTS: The operative time, return of bowel activity and return to work were the longest in the laparoscopic Davydov group (P < 0.001). The total cost was the highest in the SIS graft group (P < 0.001). The length of the neovagina was 7.9 ± 1.2 cm in the Sheares group, 7.1 ± 0.8 cm in the SIS graft group and 8.1 ± 1.1 cm in the laparoscopic Davydov group. The difference in the length of the neovagina was significant (P < 0.001). There was significant difference in the duration of continuous mould wearing (P < 0.001). There were no significant differences in the total female sexual function index (FSFI) scores or in the satisfaction scores of the male partner among the three groups. CONCLUSION: Sheares vaginoplasty and the vaginoplasty using SIS graft caused less trauma and provided similar functional results to laparoscopic peritoneal vaginoplasty. However, the patients in the Sheares group and SIS graft group needed to wear the mould for a longer duration post-surgery. Sheares vaginoplasty can provide a valuable and economic alternative method for the creation of a neovagina in patients with MRKHS.

Otologic use of porcine small intestinal submucosal graft (biodesign): A MAUDE database review.

OBJECTIVE: To review and summarize reported adverse events related to the use of porcine small intestine submucosal grafts (Biodesign™) in otologic procedures. STUDY DESIGN: Retrospective cross-sectional analysis. SETTING: Food and Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database. MATERIAL AND METHODS: The MAUDE database was queried for all medical device reports (MDR) related to otologic use of Biodesign™ (Cook Medical, Bloomington, IN) from January 2016 to November 2022. Adverse events (AEs) were identified by reviewing all reports with the basic search term "Biodesign" and "Biodesign, Otologic". Reports were individually reviewed and categorized with special attention to AEs. RESULTS: A total of 500 reports were reviewed. Since FDA approval of Biodesign™ in 2016, there have been 5 adverse events reported for use of Biodesign™ during otologic surgery (tympanoplasty, n = 3; stapes surgery, n = 2). All reported events described patient injury, and all cases required at least one revision surgery. Four cases described significant foreign body inflammatory reactions. Complications included hearing loss (n = 3), severe otalgia (n = 2), persistent perforation (n = 2), vertigo (n = 2), and facial paralysis (n = 1). CONCLUSION: The use of porcine small intestinal submucosal graft has been thought to be a safe and effective option for otologic surgery, with the advantage of availability without graft harvest in minimally invasive endoscopic surgery. However, foreign body or granulomatous reactions have been documented and should be considered prior to its use in otologic surgery.

[Effect of pH on the chelation between strontium ions and decellularized small intestinal submucosal sponge scaffolds].

OBJECTIVE: To investigate the preparation of decellularized small intestinal submucosa (dSIS) sponge scaffolds with chelated strontium (Sr) ions at different pH values, and to select the appropriate pH values for synthesizing Sr/dSIS scaffolds using the physicochemical properties and biocompatibility of the scaffolds as evaluation indexes. METHODS: (1) Sr/dSIS scaffolds preparation and grouping: After mixing dSIS solution and strontium chloride solution in equal volumes, adjusting pH of the solution to 3, 5, 7, and 9 respectively, porous scaffolds were prepared by freeze-drying method after full reaction at 37℃, which were named Sr/dSIS-3, -5, -7, and -9 respectively, and the dSIS scaffolds were used as the control group. (2) Physicochemical property evaluation: The bulk morphology of the scaffolds was observed in each group, the microscopic morphology analyzed by scanning electron microscopy, and the porosity and pore size determined, the surface elements analyzed by energy spectroscopy, the structure of functional groups analyzed by infrared spectroscopy, the chelation rate determined by atomic spectrophotometry, the water absorption rate detected by using specific gravity method, and the compression strength evaluated by universal mechanical testing machine.(3) Biocompatibility evaluation: The cytotoxicity and proliferative effect to bone mesenchymal stem cells (BMSCs) of each group were evaluated by Calcein-AM/PI double staining method. RESULTS: Scanning electron microscopy showed that the scaffolds of each group had an interconnected three-dimensional porous structure with no statistical difference in pore size and porosity. Energy spectrum analysis showed that strontium could be detected in Sr/dSIS-5, -7 and -9 groups, and strontium was uniformly distributed in the scaffolds. Functional group analysis further supported the formation of chelates in the Sr/dSIS-5, -7 and -9 groups. Chelation rate analysis showed that the Sr/dSIS-7 group had the highest strontium chelation rate, which was statistically different from the other groups (P < 0.05). The scaffolds in all the groups had good water absorption. The scaffolds in Sr/dSIS-5, -7 and -9 groups showed significantly improved mechanical properties compared with the control group (P < 0.05). The scaffolds in all the groups had good biocompatibility, and the Sr/dSIS-7 group showed the best proliferation of BMSCs. CONCLUSION: When pH was 7, the Sr/dSIS scaffolds showed the highest strontium chelation rate and the best proliferation effect of BMSCs, which was the ideal pH value for the preparation of the Sr/dSIS scaffolds.

Small intestinal submucosa xenograft to manage lower urinary tract prostheses perforation: a new path?

INTRODUCTION AND HYPOTHESIS: Tapes for stress urinary incontinence (SUI) and meshes for pelvic organ prolapse can result in postoperative complications, such as urethral (UP) or bladder (BP) perforations. Martius fat pad (MFP) is an historic procedure, widely used to treat lower urinary tract (LUT) fistulae. We report our experience with the insertion of the biological small intestinal submucosa (SIS) xenograft as an alternative to MFP in these prosthetic complications. METHODS: We conducted a retrospective, monocentric study which included all patients who underwent SIS insertion during surgical removal of tape/vaginal mesh for UP or BP from 2011 to 2019. Preoperative assessment was based on history, symptoms, physical examination and urethrocystoscopy. Primary outcome was successful repair defined as absence of any LUT defect. Secondary outcomes were complications, LUT symptoms, pain and additional SUI surgical procedures. RESULTS: Thirty-eight patients were included. Twenty-six had a UP and eight a BP. In four cases, perforation involved both the bladder neck and urethra. All LUT defects were cured. Six postoperative complications were reported (five of grade ≤ 2 and one of grade 3b according to the Clavien-Dindo classification). At the mean follow-up of 37.2 (range 6-98) months, 14 patients (36.8%) presenting a postoperative SUI underwent a SUI surgical procedure and 1 patient had a laparoscopic sacrocolpopexy for cystocele recurrence. CONCLUSION: Absorbable SIS xenograft is an effective and safe graft for the management of lower urinary tract tape and mesh perforations. The cost has to be balanced with the good results, short operative time and no fat pad complications as in MFP.

Porcine Small Intestinal Submucosa (SIS) as a Suitable Scaffold for the Creation of a Tissue-Engineered Urinary Conduit: Decellularization, Biomechanical and Biocompatibility Characterization Using New Approaches.

Bladder cancer (BC) is among the most common malignancies in the world and a relevant cause of cancer mortality. BC is one of the most frequent causes for bladder removal through radical cystectomy, the gold-standard treatment for localized muscle-invasive and some cases of high-risk, non-muscle-invasive bladder cancer. In order to restore urinary functionality, an autologous intestinal segment has to be used to create a urinary diversion. However, several complications are associated with bowel-tract removal, affecting patients' quality of life. The present study project aims to develop a bio-engineered material to simplify this surgical procedure, avoiding related surgical complications and improving patients' quality of life. The main novelty of such a therapeutic approach is the decellularization of a porcine small intestinal submucosa (SIS) conduit to replace the autologous intestinal segment currently used as urinary diversion after radical cystectomy, while avoiding an immune rejection. Here, we performed a preliminary evaluation of this acellular product by developing a novel decellularization process based on an environmentally friendly, mild detergent, i.e., Tergitol, to replace the recently declared toxic Triton X-100. Treatment efficacy was evaluated through histology, DNA, hydroxyproline and elastin quantification, mechanical and insufflation tests, two-photon microscopy, FTIR analysis, and cytocompatibility tests. The optimized decellularization protocol is effective in removing cells, including DNA content, from the porcine SIS, while preserving the integrity of the extracellular matrix despite an increase in stiffness. An effective sterilization protocol was found, and cytocompatibility of treated SIS was demonstrated from day 1 to day 7, during which human fibroblasts were able to increase in number and strongly organize along tissue fibres. Taken together, this in vitro study suggests that SIS is a suitable candidate for use in urinary diversions in place of autologous intestinal segments, considering the optimal results of decellularization and cell proliferation. Further efforts should be undertaken in order to improve SIS conduit patency and impermeability to realize a future viable substitute.

[Effects of different crosslinking treatments on the properties of decellularized small intestinal submucosa porous scaffolds].

OBJECTIVE: To compare the effects of three different crosslinkers on the biocompatibility, physical and chemical properties of decellularized small intestinal submucosa (SIS) porous scaffolds. METHODS: The SIS porous scaffolds were prepared by freeze-drying method and randomly divided into three groups, then crosslinked by glutaraldehyde (GA), 1-ethyl-3-(3-dimethylaminopropyl) carbodi-imide (EDC) and procyanidine (PA) respectively. To evaluate the physicochemical property of each sample in different groups, the following experiments were conducted. Macroscopic morphologies were observed and recorded. Microscopic morphologies of the scaffolds were observed using field emission scanning electron microscope (FESEM) and representative images were selected. Computer software (ImageJ) was used to calculate the pore size and porosity. The degree of crosslinking was determined by ninhydrin experiment. Collagenase degradation experiment was performed to assess the resistance of SIS scaffolds to enzyme degradation. To evaluate the mechanical properties, universal mechanical testing machine was used to determine the stress-strain curve and compression strength was calculated. Human bone marrow mesenchymal cells (hBMSCs) were cultured on the scaffolds after which cytotoxicity and cell proliferation were assessed. RESULTS: All the scaffolds remained intact after different crosslinking treatments. The FESEM images showed uniformed interconnected micro structures of scaffolds in different groups. The pore size of EDC group[(161.90±13.44) µm] was significantly higher than GA group [(149.50±14.65) µm] and PA group[(140.10±12.06) µm] (P < 0.05). The porosity of PA group (79.62%±1.14%) was significantly lower than EDC group (85.11%±1.71%) and GA group (84.83%±1.89%) (P < 0.05). PA group showed the highest degree of crosslinking whereas the lowest swelling ratio. There was a significant difference in the swelling ratio of the three groups (P < 0.05). Regarding to the collagenase degradation experiment, the scaffolds in PA group showed a significantly lower weight loss rate than the other groups after 7 days degradation. The weight loss rates of GA group were significantly higher than those of the other groups on day 15, whereas the PA group had the lowest rate after 10 days and 15 days degradation. PA group showed better mechanical properties than the other two groups. More living cells could be seen in PA and EDC groups after live/dead cell staining. Additionally, the proliferation rate of hBMCSs was faster in PA and EDC groups than in GA group. CONCLUSION: The scaffolds gained satisfying degree of crosslinking after three different crosslinking treatments. The samples after PA and EDC treatment had better physicochemical properties and biocompatibility compared with GA treatment. Crosslinking can be used as a promising and applicable method in the modification of SIS scaffolds.

The Mystery of the Interstitial Cells in the Urinary Bladder.

Intrinsic mechanisms to restrain smooth muscle excitability are present in the bladder, and premature contractions during filling indicate a pathological phenotype. Some investigators have proposed that c-Kit+ interstitial cells (ICs) are pacemakers and intermediaries in efferent and afferent neural activity, but recent findings suggest these cells have been misidentified and their functions have been misinterpreted. Cells reported to be c-Kit+ cells colabel with vimentin antibodies, but vimentin is not a specific marker for c-Kit+ cells. A recent report shows that c-Kit+ cells in several species coexpress mast cell tryptase, suggesting that they are likely to be mast cells. In fact, most bladder ICs labeled with vimentin antibodies coexpress platelet-derived growth factor receptor α (PDGFRα). Rather than an excitatory phenotype, PDGFRα+ cells convey inhibitory regulation in the detrusor, and inhibitory mechanisms are activated by purines and stretch. PDGFRα+ cells restrain premature development of contractions during bladder filling, and overactive behavior develops when the inhibitory pathways in these cells are blocked. PDGFRα+ cells are also a prominent cell type in the submucosa and lamina propria, but little is known about their function in these locations. Effective pharmacological manipulation of bladder ICs depends on proper identification and further study of the pathways in these cells that affect bladder functions.

Early Gastric Cancer: identification of molecular markers able to distinguish submucosa-penetrating lesions with different prognosis.

BACKGROUND: Early Gastric Cancer (EGC) reaches 25% of the gastric cancers surgically treated in some areas of Northeastern Italy and is usually characterized by a good prognosis. However, among EGCs classified according to Kodama's criteria, Pen A subgroup is characterized by extensive submucosal invasion, lymph node metastases and worse prognosis, whereas Pen B subgroup by better prognosis. The aim of the study was to characterize the differences between Pen A, Pen B and locally advanced gastric cancer (T3N0) in order to identify biomarkers involved in aggressiveness and clinical outcome. METHODS: We selected 33 Pen A, 34 Pen B and 20 T3N0 tumors and performed immunohistochemistry of mucins, copy number variation analysis of a gene panel, microsatellite instability (MSI), TP53 mutation and loss of heterozygosity (LOH) analyses. RESULTS: Pen A subgroup was characterized by MUC6 overexpression (p = 0.021). Otherwise, the Pen B subgroup was significantly associated with the amplification of GATA6 gene (p = 0.002). The higher percentage of MSI tumors was observed in T3N0 group (p = 0.002), but no significant differences between EGC types were found. Finally, TP53 gene analysis showed that 32.8% of Pen tumors have a mutation in exons 5-8 and 50.0% presented LOH. Co-occurrence of TP53 mutation and LOH mainly characterized Pen A tumors (p = 0.022). CONCLUSIONS: Our analyses revealed that clinico-pathological parameters, microsatellite status and frequency of TP53 mutations do not seem to distinguish Pen subgroups. Conversely, the amplification of GATA6 was associated with Pen B, as well as the overexpression of MUC6 and the TP53mut/LOH significantly characterized Pen A.