Small Intestinal Submucosa Research Articles

The Goat as a Model for Temporomandibular Joint Disc Replacement: Techniques for Scaffold Fixation

A state-of-the-art scaffold capable of efficiently reconstructing the temporomandibular joint (TMJ) disc after discectomy remains elusive. The major challenge has been to identify a degradable scaffold that remodels into a TMJ disc-like tissue, and prevents increased joint pathology, among other significant complications. Tissue engineering research provides a foundation for promising approaches toward the creation of successful implants/scaffolds aiming to restore the TMJ disc. In light of improving the quality of life of patients who undergo TMJ disc removal, it is critical to establish a preclinical animal model to evaluate the properties of promising scaffolds implanted post-discectomy and to determine the most efficient implantation procedures to ensure a more reliable in-depth evaluation of the biomaterial replacing the articular disc. The present study evaluated the outcomes of two protocols for the implantation of an acellular scaffold composed of an extracellular matrix (ECM) derived from the small intestinal submucosa (SIS) of the pig, as a regenerative template for the TMJ disc in a goat model. The outcomes suggest that leaving one-half of the disc medially will allow anchoring the device to the medial aspect of the joint while avoiding lateral displacement of the ECM scaffold. The goat model is ideal to assess the longevity of tissue-engineered solutions for the TMJ disc as the goat chews for 12-16 hours a day. This study provides an important reference for selecting a suitable scaffold implantation procedure and the goat model for the development of new strategies to assess TMJ disc regeneration.

Mechanical and Geometric Characterization of a Novel 2-Ply Vacuum-Pressed Biological Scaffold Patch Design for Posterior Mitral Valve Reconstruction.

To assess the mechanical properties of small intestinal submucosal extracellular matrix (SIS-ECM) iterations and choose the optimal version for evaluating functional geometrics after posterior mitral valve reconstruction. Four SIS-ECM versions (2- and 4-ply vacuum-pressed and lyophilized) underwent uniaxial tensile testing. A posterior mitral valve reconstruction patch was developed based on MRI scans (n = 5). Posterior mitral valve reconstruction using 2-ply vacuum-pressed SIS-ECM was performed (n = 7), and geometrics were evaluated using a modified left heart simulator. The vacuum-pressed iterations displayed superior maximum stress values compared to lyophilized (2-ply: median [IQR], 15.8 [15.2-19.0] vs 7.9 [7.3-8.3] MPa, p < 0.001; 4-ply: median (IQR), 15.8 -[14.6-22.0] vs 7.9 [7.6-8.4] MPa). All reconstructed valves were competent with preserved total leaflet area, but individual leaflet segment areas were redistributed. Posterior mitral valve reconstruction with our 2-ply vacuum-pressed SIS-ECM patch design was feasible in vitro. Further in vivo evaluation is warranted.

Exosomes from hypoxic urine-derived stem cells facilitate healing of diabetic wound by targeting SERPINE1 through miR-486-5p

Vascular pathologies and injuries are important factors for the delayed wound healing in diabetes. Previous studies have demonstrated that hypoxic environments could induce formation of new blood vessels by regulating intercellular communication and cellular behaviors. In this study, we have enhanced the angiogenic potential of exosomes by subjecting urine-derived stem cells (USCs) to hypoxic preconditioning. To prolong the retention of exosomes at the wound site, we have also engineered a novel dECM hydrogel termed SISMA, which was modified from porcine small intestinal submucosa (SIS). For its rapid and controllable gelation kinetics, excellent biocompatibility, and exosome release capability, the SISMA hydrogel has proven to be a reliable delivery vehicle for exosomes. The hypoxia-induced exosomes-loaded hydrogel has promoted endothelial cell proliferation, migration, and tube formation. More importantly, as evidenced by significant in vivo vascular regeneration in the early stages post-injury, it has facilitated tissue repair. This may because miR-486–5p in H-exo inhibit SERPINE1 activity in endothelial cell. Additionally, miRNA sequencing analysis suggested that the underlying mechanism for enhanced angiogenesis may be associated with the activation of classical HIF-1α signaling pathway. In summary, our study has presented a novel non-invasive, cell-free therapeutic approach for accelerating diabetes wound healing and development of a practical and efficient exosomes delivery platform.

Reconstruction of deep and perforating corneal defects in dogs-A review (Part II/III): Biomaterials and keratoprosthesis.

The surgical reconstruction of severe corneal ulcers is a common and crucial component of the clinical practice of veterinary ophthalmology. Numerous surgical techniques are used in dogs for corneal reconstruction, and these techniques may be categorized by the material used to repair the corneal lesion. The first part of the present review described procedures that utilize autogenous ocular tissues, homologous donor tissues, and heterologous donor tissues. In this second part of the review, the categories of biomaterials and keratoprosthetics will be summarized. Biomaterials that are reported for use in dogs include amniotic membrane, porcine urinary bladder acellular matrix, porcine small intestinal submucosa, acellular porcine corneal stroma, and other miscellaneous soft tissue and cartilage grafts (e.g., preserved equine renal capsule, autologous omentum, autologous buccal mucosa membrane, bovine pericardium, and homologous peritoneum). Descriptions of keratoprosthesis surgery in dogs are currently limited, but the use of artificial corneal transplants hold promise for dogs with severe, vision-compromising corneal disease that is not amenable to other reconstruction techniques. This review describes the results of experimental studies evaluating these graft materials in dogs, and it will summarize the findings and outcomes of the clinical articles published in each material category. Reporting inconsistencies and areas where additional research is required will be highlighted to help guide future studies in this area. A major aim of this review is to help identify potential subjects that could be evaluated in future investigations and that might lead to refinements in clinical practice.

Evaluation of Bi-layer Silk Fibroin Grafts for Inlay Vaginoplasty in a Rat Model.

Autologous tissues derived from bowel, buccal mucosa and skin are primarily used to repair or replace diseased vaginal segments as well as create neovaginas for male-to-female transgenders. These grafts are often limited by scarce tissue supply, donor site morbidity and post-operative complications. Bi-layer silk fibroin (BLSF) biomaterials represent potential alternatives for vaginoplasty given their structural strength and elasticity, low immunogenicity, and processing flexibility. The goals of the current study were to assess the potential of acellular BLSF scaffolds for vaginal tissue regeneration in respect to conventional small intestinal submucosal (SIS) matrices in a rat model of vaginoplasty. Inlay vaginoplasty was performed with BLSF and SIS scaffolds (N = 21 per graft) in adult female rats for up to 2months of implantation. Nonsurgical controls (N = 4) were investigated in parallel. Outcome analyses included histologic, immunohistochemical and histomorphometric evaluations of wound healing patterns; µ-computed tomography (CT) of vaginal continuity; and breeding assessments. Animals in both scaffold cohorts exhibited 100% survival rates with no severe post-operative complications. At 2months post-op, µ-CT analysis revealed normal vaginal anatomy and continuity in both graft groups similar to controls. In parallel, BLSF and SIS grafts also induced comparable constructive remodeling patterns and were histologically equivalent in their ability to support formation of vascularized vaginal neotissues with native tissue architecture, however with significantly less smooth muscle content. Vaginal tissues reconstructed with both implants were capable of supporting copulation, pregnancy and similar amounts of live births. BLSF biomaterials represent potential "off-the-shelf" candidates for vaginoplasty.

Comparison of porcine small intestinal submucosa and autologous graft material for repairing tympanic membrane perforation: a systematic review and meta-analysis.

To perform a systematic review and meta-analysis exploring the effectiveness of porcine small intestinal submucosa(pSIS) compared with autologous grafts for tympanic membrane perforation repair. A prospective meta-analysis protocol was registered on PROSPERO (International Prospective Register of Systematic Reviews) on June 5th, 2024, under protocol CRD42024551979. PubMed, Embase/Ovid and Cochrane Central databases were searched from inception to 28/05/2024 for studies comparing the use of pSIS versus autologous grafts (perichondrium, cartilage, temporalis fascia or cartilage-perichondrium) for tympanic membrane perforation repair. The outcomes evaluated were persistent perforation after surgery, operative time and hearing outcome. Statistical analyses were performed using the online Review Manager (Cochrane Collaboration). A subgroup analyses were carried out for the paediatric population. We included 1,407 patients (1447 ears) from seven records; six retrospective cohort studies and one randomised controlled trial (RCT). pSIS graft was used in 563 ear surgeries (38.1%). Four studies included children with a mean age ranging from 7.3 to 11.7 years and the other 3 studies included adults with a mean age ranging from 30.8 to 48.4 years. Follow-up ranged from 2 to 132 months. There was no statistically significant difference in the failure rate (persistent perforation) between pSIS graft and autologous graft (RR 0.95; 95% CI 0.67-1.33; p = 0.76). However, reduced operative time was associated with using pSIS grafts (MD -16.12min; 95% CI -22.94-9.31; p = < 0.00001). Tympanic membrane perforation repair with pSIS grafts had a similar failure rate and hearing outcome compared to autologous grafts and demonstrated an association with reduced operative time.

Computational Model for Early-Stage Aortic Valve Calcification Shows Hemodynamic Biomarkers.

Heart disease is a leading cause of mortality, with calcific aortic valve disease (CAVD) being the most prevalent subset. Being able to predict this disease in its early stages is important for monitoring patients before they need aortic valve replacement surgery. Thus, this study explored hydrodynamic, mechanical, and hemodynamic differences in healthy and very mildly calcified porcine small intestinal submucosa (PSIS) bioscaffold valves to determine any notable parameters between groups that could, possibly, be used for disease tracking purposes. Three valve groups were tested: raw PSIS as a control and two calcified groups that were seeded with human valvular interstitial and endothelial cells (VICs/VECs) and cultivated in calcifying media. These two calcified groups were cultured in either static or bioreactor-induced oscillatory flow conditions. Hydrodynamic assessments showed metrics were below thresholds associated for even mild calcification. Young's modulus, however, was significantly higher in calcified valves when compared to raw PSIS, indicating the morphological changes to the tissue structure. Fluid-structure interaction (FSI) simulations agreed well with hydrodynamic results and, most notably, showed a significant increase in time-averaged wall shear stress (TAWSS) between raw and calcified groups. We conclude that tracking hemodynamics may be a viable biomarker for early-stage CAVD tracking.

Pig-derived ECM-SIS provides a novel matrix gel for tumor modeling

The absence of effective extracellular matrix to mimic the natural tumor microenvironment remains a significant obstacle in cancer research. Matrigel, abundant in various biological matrix components, is limited in its application due to its high cost. This has prompted researchers to explore alternative matrix substitutes. Here, we have investigated the effects of the extracellular matrix derived from pig small intestinal submucosa (ECM-SIS) in xenograft tumor modeling. Our results showed that the pig-derived ECM-SIS effectively promotes the establishment of xenograft tumor models, with a tumor formation rate comparable to that of Matrigel. Furthermore, we showed that the pig-derived ECM-SIS exhibited lower immune rejection and fewer infiltrating macrophages than Matrigel. Gene sequencing analysis demonstrated only a 0.5% difference in genes between pig-derived ECM-SIS and Matrigel during the process of tumor tissue formation. These differentially expressed genes primarily participate in cellular processes, biological regulation, and metabolic processes. These findings emphasize the potential of pig-derived ECM-SIS as a cost-effective option for tumor modeling in cancer research.

The effect of acellular scaffold loaded with Wharton's jelly-derived stem cells and mineral pitch on healing of burn model in rat.

Severe burns often result in an exacerbated inflammatory response, which can contribute to further injury. This inflammatory response may lead to an increased risk of infection, multiple organ failure, and death. This study aimed to investigate the potential of reducing inflammation to enhance burn wound healing in rats using ovine's small intestinal submucosa as a carrier for Wharton's jelly mesenchymal stem cells (WJ-MSCs) and Mineral Pitch (MP). A rat burn model was developed, and the animals were divided into four groups: control group: burn, placebo group: scaffold-treated burn, cell experimental group: WJ-MSCs seeded scaffold-treated burn, and cell and MP experimental group: scaffolds loaded with WJ-MSCs and MP-treated burn. After treating the wounds in the relevant groups and sampling them on days 5, 14 and 21, histological and pathological parameters, and the expression of genes involved in angiogenesis and epithelialization were evaluated. The study results revealed several findings in the burn wounds. These included changes in mast cell populations, a decrease in inflammatory neutrophils and lymphocytes, an increase in fibroblasts and blood vessels, and upregulation of angiogenesis and epithelialization genes. These changes collectively contributed to enhanced wound healing in cell and MP experimental group compared to the other groups. The findings suggest that scaffolds loaded with Wharton's jelly-derived stem cells and MP can serve as engineered tools to modulate inflammatory conditions during the burn wound healing process. These interventions can improve burn wound management and promote better outcomes.

Improved Composite Hydrogel for Bioengineered Tracheal Graft Demonstrates Effective Early Angiogenesis.

Background/Objectives: Collagen-agarose hydrogel blends currently used in tracheal graft bioengineering contain relatively high concentrations of collagen to withstand mechanical stresses associated with native trachea function (e.g., breathing). Unfortunately, the high collagen content restricts effective cell infiltration into the hydrogel. In this study, we created an improved hydrogel blend with lower concentrations of collagen (<5 mg/mL) and characterized its capacity for fibroblast invasion and angiogenesis. Methods: Four collagen-agarose hydrogel blends were created: 1 mg/mL type 1 collagen (T1C) and 0.25% agarose, 1 mg/mL T1C and 0.125% agarose, 2 mg/mL T1C and 0.25% agarose, and 2 mg/mL T1C and 0.125% agarose. The hydrogel surface was seeded with fibroblasts, while both endothelial cells and fibroblasts (3:1 ratio) were mixed within the hydrogel matrix. We assessed early angiogenesis by observing fibroblast migration and endothelial cell morphology (elongation and branching) at 7 days. In addition, we performed immunostaining for alpha-smooth muscle actin (aSMA) and explored the gene expression of various angiogenic markers (including vascular endothelial growth factor; VEGF). Results: Gels with lower agarose concentrations (0.125%) with 1 or 2 mg/mL T1C were more effective in allowing early attachment and migration of surface-applied fibroblasts compared to gels with higher (0.25%) agarose concentrations. The low-agarose gels also allowed cells to quickly adopt a spread morphology and self-assemble into elongated structures indicative of early angiogenesis, while demonstrating positive immunostaining for aSMA and increased gene expression of VEGF by day 7. Conclusions: Hydrogel blends with collagen and low agarose concentrations may be effective in allowing early cellular infiltration and angiogenesis, making such gels a suitable cell substrate for use in the development of composite bioengineered tracheal grafts. The collagen-agarose hydrogel blend is meant to be cast around a three-dimensional (3D) printed polycaprolactone support structure and wrapped in porcine small intestine submucosa ECM to create an off-the-shelf bioengineered tracheal implant.

Small Intestinal Submucosa Hydrogel Loaded With Gastrodin for the Repair of Achilles Tendinopathy.

Achilles tendinopathy (AT) is an injury caused by overuse of the Achilles tendon or sudden force on the Achilles tendon, with a considerable inflammatory infiltrate. As Achilles tendinopathy progresses, inflammation and inflammatory factors affect the remodeling of the extracellular matrix (ECM) of the tendon. Gastrodin(Gas), the main active ingredient of Astrodia has anti-inflammatory, antioxidant, and anti-apoptotic properties. The small intestinal submucosa (SIS) is a naturally decellularized extracellular matrix(dECM)material and has a high content of growth factors as well as good biocompatibility. However, the reparative effects of SIS and Gas on Achilles tendinopathy and their underlying mechanisms remain unknown. Here, it is found that SIS hydrogel loaded with gastrodin restored the mechanical strength of the Achilles tendon, facilitated ECM remodeling, and restored ordered collagen arrangement by promoting the translocation of protein synthesis. It also decreases the expression of inflammatory factors and reduces the infiltration of inflammatory cells by inhibiting the NF-κB signaling pathway. It is believed that through further research, Gas + SIS may be used in the future for the treatment of Achilles tendinopathy and other Achilles tendon injury disorders.

Accelerated cartilage regeneration through immunomodulation and enhanced chondrogenesis by an extracellular matrix hydrogel encapsulating Kartogenin

Articular cartilage is crucial for the functional integrity of joints yet vulnerable to a spectrum of injuries. The adverse immune microenvironment ensuing from injury, coupled with the intrinsic property of the tissue characterized by limited cellularity, poses a significant challenge to the reconstruction of cartilage defect. In this study, an extracellular matrix hydrogel derived from porcine small intestinal submucosa (SIS) with encapsulation of Kartogenin (KGN) has been designed for the cartilage repair and regeneration. The SIS hydrogel, which possessed a three-dimensional porous structure akin to the natural cartilage, has provided a scaffold essential for the progenitor cells engaged in the repair process and sustained release of KGN. As shown by in vitro experiments, the KGN could recruit host endogenous bone marrow-derived mesenchymal stem cells (BMSCs) and induce them to differentiate into chondrocytes, thus enabling in situ cartilage regeneration without cell transplantation. Notably, the bioactive component of SIS was further revealed to possess excellent immunomodulatory capacity to induce the phenotypic shift from M1 to M2 macrophages, which could enhance the chondrogenic differentiation of BMSCs indirectly. Additionally, in vivo experiments showed that the regenerated tissues of the composite SIS hydrogel group were close to the natural hyaline cartilage. Leveraging the combined effects of KGN and SIS hydrogel, this innovative composite material shows great potential as a biomaterial for effective cartilage repair and regeneration.

EVs from cells at the early stages of chondrogenesis delivered by injectable SIS dECM promote cartilage regeneration

Articular cartilage defect therapy is still dissatisfactory in clinic. Direct cell implantation faces challenges, such as tumorigenicity, immunogenicity, and uncontrollability. Extracellular vesicles (EVs) based cell-free therapy becomes a promising alternative approach for cartilage regeneration. Even though, EVs from different cells exhibit heterogeneous characteristics and effects. The aim of the study was to discover the functions of EVs from the cells during chondrogenesis timeline on cartilage regeneration. Here, bone marrow mesenchymal stem cells (BMSCs)-EVs, juvenile chondrocytes-EVs, and adult chondrocytes-EVs were used to represent the EVs at different differentiation stages, and fibroblast-EVs as surrounding signals were also joined to compare. Fibroblasts-EVs showed the worst effect on chondrogenesis. While juvenile chondrocyte-EVs and adult chondrocyte-EVs showed comparable effect on chondrogenic differentiation as BMSCs-EVs, BMSCs-EVs showed the best effect on cell proliferation and migration. Moreover, the amount of EVs secreted from BMSCs were much more than that from chondrocytes. An injectable decellularized extracellular matrix (dECM) hydrogel from small intestinal submucosa (SIS) was fabricated as the EVs delivery platform with natural matrix microenvironment. In a rat model, BMSCs-EVs loaded SIS hydrogel was injected into the articular cartilage defects and significantly enhanced cartilage regeneration in vivo. Furthermore, protein proteomics revealed BMSCs-EVs specifically upregulated multiple metabolic and biosynthetic processes, which might be the potential mechanism. Thus, injectable SIS hydrogel loaded with BMSCs-EVs might be a promising therapeutic way for articular cartilage defect.

A multicenter randomized controlled trial comparing short- and medium-term outcomes of novel biologics and lightweight synthetic mesh for laparoscopic inguinal hernia repair.

The use of biological graft in laparoscopic inguinal hernia repair (LIHR) has been controversial, and there is a lack of high-level evidence to confirm the value of biological graft in LIHR. The purpose of this study is to evaluate the effectiveness of a novel composite biologics in LIHR. A multicenter, single-blinded, randomized controlled clinical trial was designed. Fifty patients with unilateral primary inguinal hernia were randomly assigned to the experimental and control group (1:1). The experimental group was repaired with a non-crosslinked composite extracellular matrix from porcine urinary bladder matrix and small intestinal submucosa (UBM/SIS). The control group was repaired with a lightweight, large-pore, synthetic mesh. The primary endpoint was the effectiveness rate of hernia repair. The patients were followed up for four years. No significant difference was found between the experimental group and the control group in the effective rate of hernia repair (24/24[100%] vs 21/22[95.45%], RR, 0.4667; 95%CI, 0.3294-2.304; P = 0.4783). There was no fever, seroma, infection, groin pain, foreign body discomfort or recurrence in the experimental group during the follow-up. In the control group, there were 2 cases of seroma 14days after operation, 1 case of groin discomfort 60days after operation and one case of recurrence 410days after surgery. Compared with the lightweight synthetic mesh, the novel UBM/SIS graft has comparable short-term and medium-term effectiveness in LIHR, and the incidence of postoperative complications such as seroma groin discomfort is lower. Trial registration Clinical Trials Registry: ChiCTR1800020173.

Enhanced fibrocartilage regeneration at the tendon-bone interface injury through extracellular matrix hydrogel laden with bFGF-overexpressing human urine-derived stem cells

The tendon-bone interface (TBI) is crucial in the transfer of mechanical loads; however, it is susceptible to injuries that frequently result in healing via fibrous scar tissue formation. Consequently, regeneration of the fibrocartilaginous zone has become a pivotal area subject. At present, the use of stem cells represents a notably promising approach for TBI treatment. Especially, human urine-derived stem cells (hUSCs) present a practical option for cell-based therapies. Nevertheless, the chondrogenic differentiation potential of hUSCs is limited. To address this, basic fibroblast growth factor (bFGF) was transinfected into hUSCs to bolster their differentiation capacity and facilitate the formation of fibrocartilage in the target area. Additionally, the local immune microenvironment dramatically influences TBI healing, with macrophages playing a vital role. Effective healing relies on the phenotype transition of macrophages, with an imbalance often leading to insufficient regeneration and scar tissue formation. Innovations in biomaterials have provided new avenues for TBI repair, such as the porcine small intestinal submucosa (SIS) hydrogel developed in our prior research. In addition to serving as a carrier for stem cell delivery, the hydrogel’s bioactive components support tissue repair and immune regulation. In the present study, SIS hydrogel loaded with hUSCs that overexpress bFGF was used for the treatment of TBI injury, which is expected to correct inflammatory response imbalances, and promote macrophage polarization towards healing phenotypes, creating a favorable immune microenvironment. The combined effects of bFGF and the optimized immune setting are anticipated to enhance hUSCs’ chondrogenic potential, aiding in the functional restoration of TBI injuries.

Proteomic profiling of regenerated urinary bladder tissue in a non-human primate augmentation model

Urinary bladder dysfunction can be caused by environmental, genetic, and developmental insults. Depending upon insult severity, the bladder may lose its ability to maintain volumetric capacity and intravesical pressure resulting in renal deterioration. Bladder augmentation enterocystoplasty (BAE) is utilized to increase bladder capacity to preserve renal function using autologous bowel tissue as a “patch.” To avoid the clinical complications associated with this procedure, we have engineered composite grafts comprised of autologous bone marrow mesenchymal stem cells (MSCs) co-seeded with CD34+ hematopoietic stem/progenitor cells (HSPCs) onto a pliable synthetic scaffold [poly(1,8-octamethylene-citrate-co-octanol)(POCO)] or a biological scaffold (SIS; small intestinal submucosa) to regenerate bladder tissue in our baboon bladder augmentation model. We set out to determine the global protein expression profile of bladder tissue that has undergone regeneration with the aforementioned stem cell seeded scaffolds along with baboons that underwent BAE. Data demonstrate that POCO and SIS grafted animals share high protein homogeneity between native and regenerated tissues while BAE animals displayed heterogeneous protein expression between the tissues following long-term engraftment. We posit that stem cell-seeded scaffolds can recapitulate tissue that is nearly indistinguishable from native tissue at the protein level and may be used in lieu of procedures such as BAE.

Hydrogel-Integrated Millifluidic Systems: Advancing the Fabrication of Mucus-Producing Human Intestinal Models.

The luminal surface of the intestinal epithelium is protected by a vital mucus layer, which is essential for lubrication, hydration, and fostering symbiotic bacterial relationships. Replicating and studying this complex mucus structure in vitro presents considerable challenges. To address this, we developed a hydrogel-integrated millifluidic tissue chamber capable of applying precise apical shear stress to intestinal models cultured on flat or 3D structured hydrogel scaffolds with adjustable stiffness. The chamber is designed to accommodate nine hydrogel scaffolds, 3D-printed as flat disks with a storage modulus matching the physiological range of intestinal tissue stiffness (~3.7 kPa) from bioactive decellularized and methacrylated small intestinal submucosa (dSIS-MA). Computational fluid dynamics simulations were conducted to confirm a laminar flow profile for both flat and 3D villi-comprising scaffolds in the physiologically relevant regime. The system was initially validated with HT29-MTX seeded hydrogel scaffolds, demonstrating accelerated differentiation, increased mucus production, and enhanced 3D organization under shear stress. These characteristic intestinal tissue features are essential for advanced in vitro models as they critically contribute to a functional barrier. Subsequently, the chamber was challenged with human intestinal stem cells (ISCs) from the terminal ileum. Our findings indicate that biomimicking hydrogel scaffolds, in combination with physiological shear stress, promote multi-lineage differentiation, as evidenced by a gene and protein expression analysis of basic markers and the 3D structural organization of ISCs in the absence of chemical differentiation triggers. The quantitative analysis of the alkaline phosphatase (ALP) activity and secreted mucus demonstrates the functional differentiation of the cells into enterocyte and goblet cell lineages. The millifluidic system, which has been developed and optimized for performance and cost efficiency, enables the creation and modulation of advanced intestinal models under biomimicking conditions, including tunable matrix stiffness and varying fluid shear stresses. Moreover, the readily accessible and scalable mucus-producing cellular tissue models permit comprehensive mucus analysis and the investigation of pathogen interactions and penetration, thereby offering the potential to advance our understanding of intestinal mucus in health and disease.

SDF-1α peptide-tethered SIS membrane enables biomimetic tissue regeneration via multifactorial synergetic regulation

Tissue injuries occur frequently in daily life, but remain a challenge to treat in clinical medicine. Significant progress has been made in designing materials capable of directing endogenous cells to promote tissue regeneration. However, few studies have described a material that simultaneously promotes endogenous cell recruitment, immunomodulation, angiogenesis, soft tissue healing and bone tissue regeneration. Small intestinal submucosa (SIS) membrane possesses good biocompatibility and a precise spatial structure. The stromal-derived factor-1 (SDF-1) plays an important role in recruiting resident or circulating stem cells. In this work, the derived SDF-1α peptide was modified with a collagen-binding peptide to specifically tether to the SIS membrane. During the initial phase of tissue repair, pSIS@SDF-1α promoted cell recruitment and M2 polarization of macrophages. Subsequently, pSIS@SDF-1α promoted angiogenesis as well as osteogenic differentiation of bone marrow MSCs. The results of in vivo experiments demonstrated that pSIS@SDF-1α promoted soft tissue wound repair and regenerative repair of defective bone tissue. In conclusion, these findings may have important implications for in situ tissue regeneration by orchestrating endogenous cell recruitment and host responses.

Conductive extracellular matrix derived/chitosan methacrylate/ graphene oxide-pegylated hybrid hydrogel for cell expansion.

Electrical stimulation has emerged as a cornerstone technique in the rapidly evolving field of biomedical engineering, particularly within the realms of tissue engineering and regenerative medicine. It facilitates cell growth, proliferation, and differentiation, thereby advancing the development of accurate tissue models and enhancing drug-testing methodologies. Conductive hydrogels, which enable the conduction of microcurrents in 3D in vitro cultures, are central to this advancement. The integration of high-electroconductive nanomaterials, such as graphene oxide (GO), into hydrogels has revolutionized their mechanical and conductivity properties. Here, we introduce a novel electrostimulation assay utilizing a hybrid hydrogel composed of methacryloyl-modified small intestine submucosa (SIS) dECM (SISMA), chitosan methacrylate (ChiMA), and GO-polyethylene glycol (GO-PEG) in a 3D in vitro culture within a hypoxic environment of umbilical cord blood cells (UCBCs). Results not only demonstrate significant cell proliferation within 3D constructs exposed to microcurrents and early growth factors but also highlight the hybrid hydrogel's physiochemical prowess through comprehensive rheological, morphological, and conductivity analyses. Further experiments will focus on identifying the regulatory pathways of cells subjected to electrical stimulation.

One-Year Outcome of an Ongoing Pre-Clinical Growing Animal Model for a Tissue-Engineered Valved Pulmonary Conduit.

Objectives: A self-constructed valved pulmonary conduit made out of a de-cellularized porcine small intestinal submucosal extracellular matrix biological scaffold was tested in a chronic growing lamb model. Methods: The conduit was implanted in pulmonary valve position in 19 lambs. We monitored clinical, laboratory, and echocardiographic findings until 12 months after surgery. In two animals, euthanasia was planned at nine and twelve months. Pre-mortem chest computed tomography and post-mortem pathologic work up were performed. Data are presented as frequency and percentage, median and range, or mean and standard deviation. Results: Twelve (63.2%) animals survived the perioperative period. Three unexpected deaths occurred during the follow-up period: one due to aspiration pneumonia at 23 days after surgery, and two due to early and late infective endocarditis of the conduit at 18 and 256 days. In the two animals with planned scarification, the pre-mortem CT scan revealed mild or no calcification within the conduit or valve leaflets. In the echocardiographic examination at 12 months, peak and mean systolic pressure gradients across the conduit valve were 6.5 (3-21) mmHg and 3 (2-12) mmHg, while valve regurgitation was none (n = 2), trivial (n = 5), moderate (n = 1), or severe (n = 1). No clinical or laboratory signs of hemolysis were seen. After 12 months of follow-up, the animals' body weights had increased from 33 (27-38) kg to 53 (38-66) kg (p = 0.010). Conclusions: Implantation of a valved pulmonary conduit in our growing lamb model was feasible. Infective endocarditis of the implanted valved conduit remained a significant complication.