Interlayer repair with porcine small intestinal submucosa versus internal repair with tragus cartilage in endoscopic tympanoplasty

Objective Endoscopic tympanoplasty includes various surgical methods,such as internal repair,interlayer repair,and external overlay.This technique requires autologous materials,allografts,and xenografts,which are used to repair tympanic membrane(TM)perforation.To obtain good results,appropriate surgical methods and repair materials should be selected.This study aims to assess the efficacy of repairing refractory TM perforations in the porcine small intestinal submucosa(SIS)during transcanal endoscopic type I tympanoplasty.Method A retrospective chart review was performed on patients who underwent TM perforation repair with porcine SIS and tragus cartilage between January 2022 and September 2022 at Sir Run Run Shaw Hospital,Zhejiang University School of Medicine.Perforation size,tympanic status,pre-and postoperative symptoms,follow-up data,wound healing rates,and hearing improvement were analysed.Results Of the 115 patients included in the study,56 underwent interlayer repair with porcine SIS of the TM,and 59 patients underwent internal repair with tragus cartilage.No significant difference was found between the two groups at baseline in terms of age,sex,disease course,perforation side,tympanic status,underlying disease,or preoperative infection.The total postoperative effective rate of interlayer implantation with porcine SIS was 91.07%(51 patients),and that of internal implantation with tragus cartilage was 88.14%(52 patients).No significant difference was found in terms of the graft success rate between the two surgical methods(p=0.887).Postoperative pure tone auditory(PTA)and air-bone gap(ABG)density significantly increased in both groups compared with before surgery(p<0.05).However,the postoperative PTA and ABG density were not significantly different 3 months post-surgery between the two groups(p>0.05).Compared to those in the internal implantation group,the patients in the interlayer group had a shorter operation duration(51.36±6.76 min vs.59.71±7.45 min,t=6.298,p<0.001)and less blood loss(11.91±2.61 mL vs.15.27±2.57 mL,t=7.019,p<0.001).Conclusions Our study suggests that the porcine SIS,as well as the tragus cartilage,has a high success rate in repairing irreversible TM perforation.Endoscopic tympanoplasty via interlayer implantation with porcine SIS offers distinct advantages,including the absence of donor-site incision and scar formation,and ease of graft modification and manipulation.

Decellularized small intestine submucosa/polylactic-co-glycolic acid composite scaffold for potential application in hypopharyngeal and cervical esophageal tissue repair

There has been an increase in the incidence of hypopharyngeal and cervical esophageal cancer worldwide,and hence growing needs for hypopharyngeal and cervical esophageal tissue repair.This work produced a bi-layer composite scaffold with decellularized small intestine submucosa and polylactic-co-glycolic acid,which resembled the layered architectures of its intended tissues.The decellularized small intestine submucosa contained minimal residual DNA(52.5±61.2 ng/mg)and the composite scaffold exhibited satisfactory mechanical properties(a tensile modulus of 21.1±64.8 MPa,an ultimate tensile strength of 14.0±62.9MPa and a failure strain of 26.9±65.1%).The interactions between cells and the respective layers of the scaffold were characterized by CCK-8 assays,immunostaining and Western blotting.Desirable cell proliferation and phenotypic behaviors were observed.These results have provided an important basis for the next-step in vivo studies of the scaffold,and bode well for its future clinical applications.

Surface modification of small intestine submucosa in tissue engineering

With the development of tissue engineering,the required biomaterials need to have the ability to promote cell adhesion and proliferation in vitro and in vivo.Especially,surface modification of the scaffold material has a great influence on biocompatibility and functionality of materials.The small intestine submucosa(SIS)is an extracellular matrix isolated from the submucosal layer of porcine jejunum,which has good tissue mechanical properties and regenerative activity,and is suitable for cell adhesion,proliferation and differentiation.In recent years,SIS is widely used in different areas of tissue reconstruction,such as blood vessels,bone,cartilage,bladder and ureter,etc.This paper discusses the main methods for surface modification of SIS to improve and optimize the performance of SIS bioscaffolds,including functional group bonding,protein adsorption,mineral coating,topography and formatting modification and drug combination.In addition,the reasonable combination of these methods also offers great improvement on SIS surface modification.This article makes a shallow review of the surface modification of SIS and its application in tissue engineering.

Procyanidins-crosslinked small intestine submucosa: A bladder patch promotes smooth muscle regeneration and bladder function restoration in a rabbit model

Currently the standard surgical treatment for bladder defects is augmentation cystoplasty with autologous tissues,which has many side effects.Biomaterials such as small intestine submucosa(SIS)can provide an alternative scaffold for the repair as bladder patches.Previous studies have shown that SIS could enhance the capacity and compliance of the bladder,but its application is hindered by issues like limited smooth muscle regeneration and stone formation since the fast degradation and poor mechanical properties of the SIS.Procyanidins(PC),a natural bio-crosslinking agent,has shown anti-calcification,anti-inflammatory and anti-oxidation properties.More importantly,PC and SIS can crosslink through hydrogen bonds,which may endow the material with enhanced mechanical property and stabilized functionalities.In this study,various concentrations of PC-crosslinked SIS(PC-SIS)were prepared to repair the full-thickness bladder defects,with an aim to reduce complications and enhance bladder functions.In vitro assays showed that the crosslinking has conferred the biomaterial with superior mechanical property and anti-calcification property,ability to promote smooth muscle cell adhesion and upregulate functional genes expression.Using a rabbit model with bladder defects,we demonstrated that the PC-SIS scaffold can rapidly promote in situ tissue regrowth and regeneration,in particular smooth muscle remodeling and improvement of urinary functions.The PC-SIS scaffold has therefore provided a promising material for the reconstruction of a functional bladder.

Small intestinal submucosa improves islet survival and function during in vitro culture

AIM： To evaluate the recovery and function of isolated rat pancreatic islets during in vitro culture with small intestinal submucosa （SIS）. METHODS： Pancreatic islets were isolated from Wistar rats by standard surgical procurement followed by intraductal collagenase distension, mechanical dissociation and Euroficoll purification. Purified islets were cultured in plates coated with multilayer SIS （SIS-treated group） or without multilayer SIS （standard cultured group） for 7 and 14 d in standard islet culture media of RPMI 1640. After isolation and culture, islets from both experimental groups were stained with dithizone and counted. Recovery of islets was determined by the ratio of counts after the culture to the yield of islets immediately following islet isolation. Viability of islets after the culture was assessed by the glucose challenge best with low （2.7 mmol/L） and high glucose （16.7 mmol/L） solution supplemented with 50 mmol/L 3-isobutyl-1- methylxanthine （IBMX） solution. Apoptosis of islet cells after the culture was measured by relative quantification of histone-complexed DNA fragments using ELISA. RESULTS： After 7 or 14 d of in vitro tissue culture, the recovery of islets in SIS-treated group was significantly higher than that cultured in plates without SIS coating. The recovery of islets in SIS-treated group was about twice more than that of in the control group. In SIS treated group, there was no significant difference in the recovery of islets between short- and long-term periods of culture （95.8±1.0% vs 90.8±1.5%, P〉0.05）. When incubated with high glucose （16.7 mmol/L） solution, insulin secretion in SIS-treated group showed a higher increase than that in control group after 14 d of culture （20.7±1.1 mU/L vs 11.8±1.1 mU/L, P〈0.05）. When islets were placed in high glucose solution containing IBMX, stimulated insulin secretion was higher in SlS-treated group than in control group. Calculated stimulation index of SlS-treated group was about 23 times of control group. In addition, the stimulation index of SlS-treated group remained constant regardless of short- and long- term periods of culture （9.5±0.2 vs 10.2±1.2, P〉0.05）. Much less apoptosis of islet cells occurred in SlS-treated group than in control group after the culture. CONCLUSION： Co-culture of isolated rat islets with native sheet-like SIS might build an extracellular matrix for islets and provide possible biotrophic and growth factors that promote the recovery and subsequent function of islets.

Use of small intestinal submucosa graft for repair of anterior urethral strictures

Objective To investigate the feasibility of using small intestinal submucosa ( SIS) graft for repair of anterior urethral strictures. Methods From June 2009 to August 2010,18 men ( mean age,38 yrs) with anterior urethral strictures underwent urethroplasty using a four layer SIS as an onlay patch graft. SIS was used to

Bioactive mineralized small intestinal submucosa acellular matrix/PMMA bone cement for vertebral bone regeneration

Polymethylmethacrylate(PMMA)bone cement extensively utilized for the treatment of osteoporotic vertebral compression fractures due to its exceptional handleability and mechanical properties.Nevertheless,the clinical application of PMMA bone cement is restricted by its poor bioactivity and excessively high modulus of elasticity.Herein,mineralized small intestinal submucosa(mSIS)was incorporated into PMMA to prepare a partially degradable bone cement(mSIS-PMMA)that provided suitable compressive strength and reduced elastic modulus compared to pure PMMA.The ability of mSIS-PMMA bone cement to promote the attachment,proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells was shown through cellular experiments carried out in vitro,and an animal osteoporosis model validated its potential to improve osseointegration.Considering these benefits,mSIS-PMMA bone cement shows promising potential as an injectable biomaterial for orthopedic procedures that require bone augmentation.

Porcine Small Intestinal Submucosa Mesh for Treatment of Pelvic Organ Prolapsed

Background：Pelvic organ prolapse （POP） is a major health concern that affects women.Surgeons have increasingly used prosthetic meshes to correct POP.However,the most common used is synthetic mesh,and absorbable mesh is less reported.This research aimed to evaluate the clinical effectiveness of porcine small intestinal submucosa （SIS）.Methods：Consecutive forty POP patients who met the inclusion criteria underwent pelvic reconstruction surgery with SIS between March 2012 and December 2013.The patients＆#39; clinical characteristics were recorded preoperatively.Surgical outcomes,measured by objective and subjective success rates,were investigated.We evaluated the quality of life （QOL） using the Pelvic Floor Distress Inventory-20 （PFDI-20） and the Pelvic Floor Impact Questionnaire-7 （PFIQ-7）.Sexual QOL was assessed by the Pelvic Organ Prolapse/Urinary Incontinence Sexual Function Questionnaire-12 （P1SQ-12）.Results：At postoperative 12 months,the subjective recurrence rate （7.5%） was much lower than the objective recurrence rate （40.0%）.Postoperatively,no erosion was identified.One underwent a graft release procedure because of urinary retention,and one had anus sphincter reconstruction surgery due to defecation urgency.Another experienced posterior vaginal wall infection where the mesh was implanted,accompanied by severe vaginal pain.Estrogen cream relieved the pain.One patient with recurrence underwent a secondary surgery with Bard Mesh because of stage 3 anterior vaginal wall prolapse.Scoring system of PFDI-20 was from 59.150 ± 13.143 preoperatively to 8.400 ± 4.749 postoperatively and PFIQ-7 was from 73.350 ± 32.281 to 7.150 ± 3.110,while PISQ-12 was from 15.825 ± 4.050 to 12.725 ± 3.471.Conclusions：QOL and the degree of subjective satisfaction were significantly improved postoperatively.Anterior repair deserves more attention because of the higher recurrence rate.The long-term follow-up of the patient is warranted to draw firm conclusion.

Tissue engineered esophagus by copper——small intestinal submucosa graft for esophageal repair in a canine model

Acellular porcine small intestinal submucosa(SIS)has been used for esophagoplasty with success in a canine model.However,it did not lead to complete epithelialization.For better reconstruction,a cellular component is required.Moreover,promotion of angiogenesis with copper has been widely recognized by basic research as well as clinical studies.In this study,we have evaluated the feasibility and effectiveness of combined Cu and SIS(SIS-Cu patch)for the esophageal repair using a canine model.Eighteen male beagle dogs were subjected to surgical resection to produce cervical esophageal defects(5 cm in length,180°in range).SIS with Cu(5 or 25μmol L 1copper)or without Cu was patched on the esophageal defects.Barium esophagram and histology exam were carried out to evaluate the effectiveness of the therapy.As shown,the SIS-Cu graft promoted re-epithelialization,re-vascularization and muscular regeneration.SIS-Cu patch is more effective than SIS alone for esophageal repair,and the SIS+25μmol L 1Cu group demonstrated additional advantages over the SIS+5μmol L 1Cu.

Co-administration of platelet-rich plasma and small intestinal submucosa is more beneficial than their individual use in promoting acute skin wound healing

Background:Acute skin wounds may compromise the skin barrier,posing a risk of infection.Small intestinal submucosa(SIS)is widely used to treat acute and chronic wounds.However,the efficacy of SIS to accelerate wound healing still needs to be improved to meet clinical demands.To tackle this problem,platelet-rich plasma(PRP)is used due to its potency to promote proliferation,migration and adhesion of target cells.In this study,we applied PRP and SIS to skin wounds to explore their effects on wound healing by evaluating re-epithelialization,collagen production,angiogenesis and the inflammatory response.Methods:A1×1-cm full-thickness skin defectwas established in mice.Sixty mice were divided into four treatment groups:PRP+SIS,PRP,SIS and control.On days 3,5,7,10 and 14 post-surgery,tissue specimens were harvested.Haematoxylin and eosin,Masson’s trichrome,immunohistochemical and immunofluorescence double staining were used to visualize epidermal thickness,collagen and vascular regeneration and inflammation.Results:Wound contraction in the PRP and PRP+SIS groups was significantly greater,compared with the other groups,on days 3 and 5 post-surgery.A histological analysis showed higher collagen expression in the PRP and PRP+SIS groups on day 7,whichwas associated with a thicker epidermal layer on day 14.In addition,immunohistochemical staining showed that CD31-positive blood vessels and vascular endothelial growth factor expression in the PRP+SIS and PRP groups were significantly higher,compared with the control group.Furthermore,immunofluorescence double staining showed that the number of M1 and M2 macrophages in the PRP+SIS and PRP groups was higher,compared with the control and SIS groups alone,on day 3.However,on day 7,the number of M1 macrophages dramatically decreased in the PRP+SIS and PRP groups.The ratio of M2 to M1 macrophages in the PRP+SIS and PRP groups was 3.97 and 2.93 times that of the control group and 4.56 and 3.37 times that of the SIS group,respectively.Conclusion:Co-administration of SIS and PRP has a better effect on promoting angiogenesis,reepithelialization and collagen regeneration in managing acute wound healing than either agent alone.

Analysis of mechanical response of fistula plug for structure optimization

Anal fistula is one of the three greatest anorectal diseases with a high prevalence. The traditional treatments（e.g., surgery） for fistula have limitations due to damage to the internal anal sphincter of patients. With recent advances in biomaterials, treatments based on biomaterial filling （e.g., scleraprotein injection, fistula plug） have emerged as novel therapies for fistula. The anal fistula plug （e.g., based on small intestinal submucosa （SIS）） has attracted increasing attention because of short term healing rate and biocompatibility. However, challenges remain for this method such as plug falling as observed in clinics. To address this, this paper analyzes the case of SIS falling under physiological condition from mechanical point of view using ANSYS simulation. It then proposes three new geometrical structures for fistula plug and compares their mechanical behavior （e.g., axial stress, reaction of constraint） with that of clinically used structure （cone shape）. Based on the simulation, it optimizes the geometric parameters of fistula plug. The approach developed here can help to improve the design of fistula plug for better clinical treatments.

Enhancing cartilage regeneration and repair through bioactive and biomechanical modification of 3D acellular dermal matrix

Acellular dermal matrix(ADM)shows promise for cartilage regeneration and repair.However,an effective decellularization technique that removes cellular components while preserving the extracellular matrix,the transformation of 2D-ADM into a suitable 3D scaffold with porosity and the enhancement of bioactive and biomechanical properties in the 3D-ADM scaffold are yet to be fully addressed.In this study,we present an innovative decellularization method involving 0.125%trypsin and 0.5%SDS and a 1%Triton X-100 solution for preparing ADM and converting 2D-ADM into 3D-ADM scaffolds.These scaffolds exhibit favorable physicochemical properties,exceptional biocompatibility and significant potential for driving cartilage regeneration in vitro and in vivo.To further enhance the cartilage regeneration potential of 3D-ADM scaffolds.we incorporated porcine-derived small intestinal submucosa(SIS)for bioactivity and calcium sulfate hemihydrate(CSH)for biomechanical reinforcement.The resulting 3D-ADM+SIS scaffolds displayed heightened biological activity,while the 3D-ADM+CSH scaffolds notably bolstered biomechanical strength.Both scaffold types showed promise for cartilage regeneration and repair in vitro and in vivo,with considerable improvements observed in repairing cartilage defects within a rabbit articular cartilage model.In summary,this research introduces a versatile 3D-ADM scaffold with customizable bioactive and biomechanical properties,poised to revolutionize the field of cartilageregeneration.

Visualization of vascular ultrastructure during osteogenesis by tissue engineering technique

The aim of this paper was to observe and visualize the changes in osteoblasts by electron microscopy during osteogenesis using tissue engineering technique.We also studied the feasibility of improving tissue vascularization of the engineered bone by using small intestine submucosa(SIS)as the scaffold.Bone mesenchymal stem cells(BMSCs)were isolated by gradient centrifugation method.Bone mesenchymal stem cells were seeded in the SIS,and the scaffold-cell constructs were cultured in vitro for 2 weeks.Small intestine submucosa without BMSCs served as control.Both SIS scaffolds were then implanted subcutaneously in the dorsa of athymic mice.The implants were harvested after in vivo incubation for 4,8 and 12 weeks.The changes in osteoblasts and vascularization were observed under a transmission electron microscope and a scanning electron microscope.The BMSCs grew quite well,differentiating on the surface of the SIS and secreting a great deal of extracellular matrices.The scaffold-cell constructs formed a lot of bone and blood vessels in vivo.The scaffold degraded after 12 weeks.No osteoblasts,but vascularization and fibroblasts were observed,in the control.The SIS can be used as a scaffold for constructing tissue-engineered bone as it can improve the formation of bone and vessels in vivo.

Promotion of right ventricular outflow tract reconstruction using a novel cardiac patch incorporated with hypoxia-pretreated urine-derived stem cells

Approximately 25%of patients with congenital heart disease require implantation of patches to repair.However,most of the currently available patches are made of inert materials with unmatched electrical conductivity and mechanical properties,which may lead to an increased risk for arrhythmia and heart failure.In this study,we have developed a novel Polyurethane/Small intestinal submucosa patch(PSP)with mechanical and electrical properties similar to those of the native myocardial tissue,and assessed its feasibility for the reconstruction of right ventricular outflow tract.A right ventricular outflow tract reconstruction model was constructed in 40 rabbits.Compared with commercially available bovine pericardium patch,the PSP patch has shown better histocompatibility and biodegradability,in addition with significantly improved cardiac function.To tackle the significant fibrosis and relatively poor vascularization during tissue remodeling,we have further developed a bioactive patch by incorporating the PSP composites with urine-derived stem cells(USCs)which were pretreated with hypoxia.The results showed that the hypoxia-pretreated bioactive patch could significantly inhibit fibrosis and promote vascularization and muscularization,resulting in better right heart function.Our findings suggested that the PSP patch combined with hypoxia-pretreated USCs may provide a better strategy for the treatment of congenital heart disease.