Search Results (10)

Milk is an essential component of the diet. Among its diverse molecular constituents, it contains nanoscale entities, known as extracellular vesicles (EVs), which play a pivotal role in intercellular communication. In particular, milk-derived EVs (MEVs) influence intestinal homeostasis by mitigating inflammatory responses, modulating gut microbiota composition, and contributing to epithelial integrity preservation and restoration. Currently, there are no information regarding their impact on intestinal connective tissue. Here, we investigate bovine MEV effects on the porcine gut stromal compartment, exposing intestinal decellularized bio-scaffolds repopulated with primary intestinal stromal fibroblasts, to different MEV concentrations (10⁶, 10⁸, and 10¹⁰ particles/mL). We observed a dose-dependent effect of MEVs on stromal fibroblast proliferation rate at concentrations higher than 10⁶ particles/mL. In addition, when MEVs were used to pre-condition the decellularized intestinal bio-scaffolds prior to cell repopulation, fibroblast growth was further boosted. Overall, these findings suggest that MEVs may play a significant role in promoting tissue remodeling and repair. This activity appears particularly relevant for enhancing intestinal homeostasis and resilience, as stromal fibroblasts contribute to the maintenance of gut integrity, barrier function, and immune balance. Moreover, the data here presented suggests the possibility of using MEVs to develop serum-free, chemically defined culture media for the generation of advanced three-dimensional (3D) models and intestinal artificial organs. Full article

Uncontrolled fibrosis via excess deposition of extracellular matrix (ECM) is a hallmark of hypertrophic scars and keloids. A decellularized ECM biomaterial from porcine small intestinal submucosa (SIS; Biodesign or BioD, Cook Biotech, Inc.) is widely used in clinical applications for tissue repair. The objective of the current study was to test the effects of BioD scaffolds, as compared with collagen constructs, on normal human skin (nFB) and keloid fibroblasts (kFBs). Immortalized human dermal fibroblasts (hFBs) and human keloid fibroblasts (hKFs) were utilized for all experiments. Cells were cultured either on BioD membranes or on collagen gel (used as a control). To investigate pro-fibrotic signaling pathways, real-time quantitative PCR (qPCR), ELISA, and gene knockdown studies were conducted on cultured cells. ECM gene expression array revealed that BioD significantly attenuated (p < 0.05) the expression of thrombospondin-1 and fibronectin-1, two drivers of fibrosis in nFB as well as kFB. BioD-repressed thrombospondin-1 and fibronectin-1 gene expression manifested as significant downregulation (n = 5–6; p < 0.05) of both proteins in nFB and kFB. The levels of latent transforming-growth factor (LAP-TGFβ-1) were markedly reduced (n = 5; p < 0.05) in both nFB and kFB cultured on BioD, but not the other constructs. Knockdown of FN1 using siRNA significantly attenuated (n = 5, p < 0.05) pro-fibrotic responses, including expression of Col1A1 and the levels of LAP-TGFβ-1 in nFB, suggesting that downregulation of FN1 by BioD is one of the primary underlying mechanisms of attenuated pro-fibrotic responses in keloid fibroblasts. This study reports that a decellularized ECM scaffold may significantly attenuate pro-fibrotic responses in both normal and keloid fibroblasts via TSP1 and FN1-dependent mechanisms. Full article

In recent years, great interest has been focused on the development of highly reproducible 3D in vitro models that are able to mimic the physiological architecture and functionality of native tissues. To date, a wide range of techniques have been proposed to recreate an intestinal barrier in vitro, including synthetic scaffolds and hydrogels, as well as complex on-a-chip systems and organoids. Here, we describe a novel protocol for the generation of an artificial intestine based on the creation of decellularized bio-scaffolds and their repopulation with intestinal stromal and epithelial cells. Organs collected at the local slaughterhouse are subjected to a decellularization protocol that includes a freezing/thawing step, followed by sequential incubation in 1% SDS for 12 h, 1% Triton X-100 for 12 h, and 2% deoxycholate for 12 h. At the end of the procedure, the generated bio-scaffolds are repopulated with intestinal fibroblasts and then with epithelial cells. The protocol described here represents a promising and novel strategy to generate an in vitro bioengineered intestine platform able to mimic some of the complex functions of the intestinal barrier, thus constituting a promising 3D strategy for nutritional, pharmaceutical, and toxicological studies. Full article

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. Full article

Traditional goal of microfabrication was to limitedly construct nano- and micro-geometries on silicon or quartz wafers using various semiconductor manufacturing technologies, such as photolithography, soft lithography, etching, deposition, and so on. However, recent integration with biotechnologies has led to a wide expansion of microfabrication. In particular, many researchers studying pharmacology and pathology are very interested in producing in vitro models that mimic the actual intestine to study the effectiveness of new drug testing and interactions between organs. Various bio–microfabrication techniques have been developed while solving inherent problems when developing in vitro micromodels that mimic the real large intestine. This intensive review introduces various bio–microfabrication techniques that have been used, until recently, to realize two-dimensional and three-dimensional biomimetic experimental models. Regarding the topic of gut chips, two major review subtopics and two-dimensional and three-dimensional gut chips were employed, focusing on the membrane-based manufacturing process for two-dimensional gut chips and the scaffold-based manufacturing process for three-dimensional gut chips, respectively. Full article

Critical valve diseases in infants have a very poor prognosis for survival. Particularly challenging is for the valve replacement to support somatic growth. From a valve regenerative standpoint, bio-scaffolds have been extensively investigated recently. While bio-scaffold valves facilitate acute valve functionality, their xenogeneic properties eventually induce a hostile immune response. Our goal was to investigate if a bio-scaffold valve could be deposited with tissues derived from allogeneic stem cells, with a specific dynamic culture protocol to enhance the extracellular matrix (ECM) constituents, with subsequent stem cell removal. Porcine small intestinal submucosa (PSIS) tubular-shaped bio-scaffold valves were seeded with human bone marrow-derived mesenchymal stem cells (hBMMSCs), cultured statically for 8 days, and then exposed to oscillatory fluid-induced shear stresses for two weeks. The valves were then safely decellularized to remove the hBMMSCs while retaining their secreted ECM. This de novo ECM was found to include significantly higher (p < 0.05) levels of elastin compared to the ECM produced by the hBMMSCs under standard rotisserie culture. The elastin-rich valves consisted of ~8% elastin compared to the ~10% elastin composition of native heart valves. Allogeneic elastin promotes chemotaxis thereby accelerating regeneration and can support somatic growth by rapidly integrating with the host following implantation. As a proof-of-concept of accelerated regeneration, we found that valve interstitial cells (VICs) secreted significantly more (p < 0.05) collagen on the elastin-rich matrix compared to the raw PSIS bio-scaffold. Full article

Among the many biological scaffold materials currently available for clinical use, the small intestinal submucosa (SIS) is an effective material for wound healing. SIS contains numerous active forms of extracellular matrix that support angiogenesis, cell migration, and proliferation, providing growth factors involved in signaling for tissue formation and assisting wound healing. SIS not only serves as a bioscaffold for cell migration and differentiation, but also restores the impaired dynamic reciprocity between cells and the extracellular matrix, ultimately driving wound healing. Here, we review the evidence on how SIS can shift the biochemical balance in a wound from chronic to an acute state. Full article

The combination of pharmacologic and endoscopic therapies is the gold standard for treating intestinal failures. The possibility of chemical solubility in water is mandatory for intelligent capsules. Functionalised silk fibroin with peptides and covalently linking different molecular entities to its structure make this protein a platform for preparing gels dissolving in the small and large intestine for drug delivery. In the present study, we linked a peptide containing the cell-adhesive motif Arginine–Glycine–Aspartic acid (RGD) to degummed silk fibres (DSF). Regenerated silk fibroin (RS) films obtained by dissolving functionalised DSF in formic acid were used to prepare composite gelatin. We show that such composite gelatin remains stable and elastic in the simulated gastric fluid (SGF) but can dissolve in the small and large intestines’ neutral-pH simulated intestine fluid (SIF). These findings open up the possibility of designing microfabricated and physically programmable scaffolds that locally promote tissue regeneration, thanks to bio-enabled materials based on functionalised regenerated silk. Full article

The utility of implanting a bioscaffold mitral valve consisting of porcine small intestinal submucosa (PSIS) in a juvenile baboon model (12 to 14 months old at the time of implant; n = 3) to assess their in vivo tissue remodeling responses was investigated. Our findings demonstrated that the PSIS mitral valve exhibited the robust presence of de novo extracellular matrix (ECM) at all explantation time points (at 3-, 11-, and 20-months). Apart from a significantly lower level of proteoglycans in the implanted valve’s annulus region (p < 0.05) at 3 months compared to the 11- and 20-month explants, there were no other significant differences (p > 0.05) found between any of the other principal valve ECM components (collagen and elastin) at the leaflet, annulus, or chordae tendinea locations, across these time points. In particular, neochordae tissue had formed, which seamlessly integrated with the native papillary muscles. However, additional processing will be required to trigger accelerated, uniform and complete valve ECM formation in the recipient. Regardless of the specific processing done to the bioscaffold valve, in this proof-of-concept study, we estimate that a 3-month window following bioscaffold valve replacement is the timeline in which complete regeneration of the valve and integration with the host needs to occur. Full article

Tissue engineering and regenerative medicine involve many different artificial and biologic materials, frequently integrated in composite scaffolds, which can be repopulated with various cell types. One of the most promising scaffolds is decellularized allogeneic extracellular matrix (ECM) then recellularized by autologous or stem cells, in order to develop fully personalized clinical approaches. Decellularization protocols have to efficiently remove immunogenic cellular materials, maintaining the nonimmunogenic ECM, which is endowed with specific inductive/differentiating actions due to its architecture and bioactive factors. In the present paper, we review the available literature about the development of grafts from decellularized human tissues/organs. Human tissues may be obtained not only from surgery but also from cadavers, suggesting possible development of Human Tissue BioBanks from body donation programs. Many human tissues/organs have been decellularized for tissue engineering purposes, such as cartilage, bone, skeletal muscle, tendons, adipose tissue, heart, vessels, lung, dental pulp, intestine, liver, pancreas, kidney, gonads, uterus, childbirth products, cornea, and peripheral nerves. In vitro recellularizations have been reported with various cell types and procedures (seeding, injection, and perfusion). Conversely, studies about in vivo behaviour are poorly represented. Actually, the future challenge will be the development of human grafts to be implanted fully restored in all their structural/functional aspects. Full article