Whole rat stomach decellularisation using a detergent-enzymatic protocol

Characterization of decellularized porcine oviduct- and uterine-derived scaffolds evaluated by spermatozoa-based biocompatibility and biotoxicity

Decellularized extracellular matrix (dECM) are widely utilized in regenerative medicine and tissue engineering due to their ability to promote cell growth, proliferation, and differentiation. In reproduction, research is focused on the utilization of these scaffolds to treat pathologies causing reproductive dysfunction or to improve assisted reproduction technologies (ARTs). We developed an efficient protocol employing the immersion-agitation technique to decellularize porcine oviductal and uterine sections, comparing the efficacy of fresh versus frozen treatments. Both methods successfully generated acellular matrices with less than 3 % residual DNA, effectively preserving structural and protein integrity. Scanning and transmission electron microscopy confirmed the ultrastructural integrity, whereas Masson's Trichrome staining highlighted better collagen preservation in frozen treatments. Proteomic analysis of decellularized scaffolds revealed collagen and key macromolecules such as laminin, filamin, dermatopontin, and fibronectin, which are essential for extracellular matrix structure and cell functions such as adhesion and migration. Innovatively, we assessed the biocompatibility and cytotoxicity of the scaffolds using spermatozoa, demonstrating that thorough washing ensures the scaffold biocompatibility without compromising sperm viability or motility. Our findings not only contribute to the standardization of decellularization protocols for female reproductive organs but also emphasize the importance of evaluating sperm biocompatibility to ensure the safety of dECM scaffolds.

Stomach engineering: region-specific characterization of the decellularized porcine stomach

PURPOSE

Patients affected by microgastria, severe gastroesophageal reflux, or those who have undergone subtotal gastrectomy, have commonly described reporting dumping syndromes or other symptoms that seriously impair the quality of their life. Gastric tissue engineering may offer an alternative approach to treating these pathologies. Decellularization protocols have great potential to generate novel biomaterials for large gastric defect repair. There is an urgency to define more reliable protocols to foster clinical applications of tissue-engineered decellularized gastric grafts.

METHODS

In this work, we investigated the biochemical and mechanical properties of decellularized porcine stomach tissue compared to its native counterpart. Histological and immunofluorescence analyses were performed to screen the quality of decellularized samples. Quantitative analysis was also performed to assess extracellular matrix composition. At last, we investigated the mechanical properties and cytocompatibility of the decellularized tissue compared to the native.

RESULTS

The optimized decellularization protocol produced efficient cell removal, highlighted in the absence of native cellular nuclei. Decellularized scaffolds preserved collagen and elastin contents, with partial loss of sulfated glycosaminoglycans. Decellularized gastric tissue revealed increased elastic modulus and strain at break during mechanical tensile tests, while ultimate tensile strength was significantly reduced. HepG2 cells were seeded on the ECM, revealing matrix cytocompatibility and the ability to support cell proliferation.

CONCLUSION

Our work reports the successful generation of acellular porcine gastric tissue able to support cell viability and proliferation of human cells.

Zinc Deficiency Exacerbates Bisphenol A-Induced Hepatic and Renal Damage: Delineation of Molecular Mechanisms

Zinc (Zn) plays an important role in the maintenance of redox status in the biological system. Zn deficiency has been found to be associated with negative effects on the functioning of many organ systems, including hepatic and renal systems. Bisphenol A (BPA) can alter Zn homeostasis and perturb the physiological system by provoking oxidative stress, which can lead to damage of different organs such as reproductive, immune, neuroendocrine, hepatic and renal systems. The present study aims to investigate the toxicity of BPA in Zn deficient condition in the liver and kidney of rat and to correlate its synergistic actions. Zn deficiency was induced by feeding Zn-deficient diet (ZDD), and BPA was administered orally (100 mg/kg/d). Male Sprague-Dawley rats were divided into four groups: NPD + Vehicle (normal feed and water), NPD + BPA (100 mg/kg/d), ZDD + Vehicle (fed with Zn-deficient diet only) and ZDD + BPA (Zn-deficient diet + BPA; 100 mg/kg/d) for 8 weeks. Biochemical, histopathological, TUNEL assay and protein expression profiles were determined to decipher the oxidative damage induced by ZDD and the toxicant BPA. Expression profile of nuclear factor erythroid 2-related factor 2, proliferating cell nuclear antigen, kelch-like ECH-associated protein 1, superoxide dismutase-1, metallothionein and apoptosis incidence showed that ZDD and BPA have a synergistic exacerbation effect on the liver and kidney of rat.

Cardiac-derived extracellular matrix: A decellularization protocol for heart regeneration

Extracellular matrix (ECM) is a fundamental component of the heart, guiding vital cellular processes during organ homeostasis. Most cardiovascular diseases lead to a remarkable remodeling of the ECM, accompanied by the formation of a fibrotic tissue that heavily compromises the heart function. Effective therapies for managing fibrosis and promoting physiological ECM repair are not yet available. The production of a decellularized extracellular matrix (d-ECM) serving as a three-dimensional and bioactive scaffold able to modulate cellular behavior and activities is considered crucial to achieve a successful regeneration. The protocol represents a step-by-step method to obtain a decellularized cardiac matrix through the combination of sodium dodecyl sulphate (SDS) and Triton X-100. Briefly, cardiac samples obtained from left ventricles of explanted, pathological human hearts were dissected and washed to remove residual body fluids. Samples were then snap-frozen and sliced by a cryostat into 350 μm thick sections. The sections obtained were decellularized using a solution containing 1% Triton X-100 and 1% SDS in combination, for 24 hours, until observing the color change from brownish-red to translucent-white. As a result, the protocol shows efficiency in preserving ECM architecture and protein composition during the whole process, suggesting that it is worthwhile, highly reproducible and produces a well- preserved decellularized extracellular matrix from cardiac samples. Notwithstanding, some limitations need to be addressed, such as the risk for microbial contamination and the unpredictable trend of the protocol when applied to decellularize samples other than myocardium, vessels, or skin. These issues require antibiotics mixture supplement during the procedure followed by UV sterilization, and appropriate adjustments for a tissue-specific utilization, respectively. The protocol is intended to produce a cardiac d-ECM for cell settlement, representing the ideal scaffold for tissue engineering purposes.

3D bioprinting of multi-layered segments of a vessel-like structure with ECM and novel derived bioink

3D-Bioprinting leads to the realization of tridimensional customized constructs to reproduce the biological structural complexity. The new technological challenge focuses on obtaining a 3D structure with several distinct layers to replicate the hierarchical organization of natural tissues. This work aims to reproduce large blood vessel substitutes compliant with the original tissue, combining the advantages of the 3D bioprinting, decellularization, and accounting for the presence of different cells. The decellularization process was performed on porcine aortas. Various decellularization protocols were tested and evaluated through DNA extraction, quantification, and amplification by PCR to define the adequate one. The decellularized extracellular matrix (dECM), lyophilized and solubilized, was combined with gelatin, alginate, and cells to obtain a novel bioink. Several solutions were tested, tuning the percentage of the components to obtain the adequate structural properties. The geometrical model of the large blood vessel constructs was designed with SolidWorks, and the construct slicing was done using the HeartWare software, which allowed generating the G-Code. The final constructs were 3D bioprinted with the Inkredible + using dual print heads. The composition of the bioink was tuned so that it could withstand the printing of a segment of a tubular construct up to 10 mm and reproduce the multicellular complexity. Among the several compositions tested, the suspension resulting from 8% w/v gelatin, 7% w/v alginate, and 3% w/v dECM, and cells successfully produced the designed structures. With this bioink, it was possible to print structures made up of 20 layers. The dimensions of the printed structures were consistent with the designed ones. We were able to avoid the double bioink overlap in the thickness, despite the increase in the number of layers during the printing process. The optimization of the parameters allowed the production of structures with a height of 20 layers corresponding to 9 mm. Theoretical and real structures were very close. The differences were 14% in height, 20% internal diameter, and 9% thickness. By tailoring the printing parameters and the amount of dECM, adequate mechanical properties could be met. In this study, we developed an innovative printable bioink able to finely reproduce the native complex structure of the large blood vessel.

3D Printing: Advancement in Biogenerative Engineering to Combat Shortage of Organs and Bioapplicable Materials

Abstract

Organ or cell transplantation is medically evaluated for end-stage failure saving or extending the lives of thousands of patients who are suffering from organ failure disorders. The unavailability of adequate organs for transplantation to meet the existing demand is a major challenge in the medical field. This led to day-day-increase in the number of patients on transplant waiting lists as well as in the number of patients dying while on the queue. Recently, technological advancements in the field of biogenerative engineering have the potential to regenerate tissues and, in some cases, create new tissues and organs. In this context, major advances and innovations are being made in the fields of tissue engineering and regenerative medicine which have a huge impact on the scientific community is three-dimensional bioprinting (3D bioprinting) of tissues and organs. Besides this, the decellularization of organs and using this as a scaffold for generating new organs through the recellularization process shows promising results. This review discussed about current approaches for tissue and organ engineering including methods of scaffold designing, recent advances in 3D bioprinting, organs regenerated successfully using 3D printing, and extended application of 3D bioprinting technique in the field of medicine. Besides this, information about commercially available 3D printers has also been included in this article.

Lay Summary

Today's need for organs for the transplantation process in order to save a patient's life or to enhance the survival rate of diseased one is the prime concern among the scientific community. Recent, advances in the field of biogenerative engineering have the potential to regenerate tissues and create organs compatible with the patient's body. In this context, major advances and innovations are being made in the fields of tissue engineering and regenerative medicine which have a huge impact on the scientific community is three-dimensional bioprinting (3D bioprinting) of tissues and organs. Besides this, the decellularization of organs and using this as a scaffold for generating new organs through the recellularization process shows promising results. This review dealt with the current approaches for tissue and organ engineering including methods of scaffold designing, recent advances in 3D bioprinting, organs regenerated successfully using 3D printing, and extended application of 3D bioprinting technique in the field of medicine. Furthermore, information about commercially available 3D printers has also been included in this article.

Bioreactivity of decellularized animal, plant, and fungal scaffolds: perspectives for medical applications

Numerous biomedical applications imply supportive materials to improve protective, antibacterial, and regenerative abilities upon surgical interventions, oncotherapy, regenerative medicine, and others. With the increasing variability of the possible sources, the materials of natural origin are among the safest and most accessible biomedical tools. Animal, plant, and fungal tissues can further undergo decellularization to improve their biocompatibility. Decellularized scaffolds lack the most reactive cellular material, nuclear and cytoplasmic components, that predominantly trigger immune responses. At the same time, the outstanding initial three-dimensional microarchitecture, biomechanical properties, and general composition of the scaffolds are preserved. These unique features make the scaffolds perfect ready-to-use platforms for various biomedical applications, implying cell growth and functionalization. Decellularized materials can be repopulated with various cells upon request, including epithelial, endothelial, muscle and neuronal cells, and applied for structural and functional biorepair within diverse biological sites, including the skin and musculoskeletal, cardiovascular, and central nervous systems. However, the molecular and cellular mechanisms behind scaffold and host tissue interactions remain not fully understood, which significantly restricts their integration into clinical practice. In this review, we address the essential aspects of decellularization, scaffold preparation techniques, and its biochemical composition and properties, which determine the biocompatibility and immunogenicity of the materials. With the integrated evaluation of the scaffold profile in living systems, decellularized animal, plant, and fungal scaffolds have the potential to become essential instruments for safe and controllable biomedical applications.

Matrix-Bound Nanovesicles: The Effects of Isolation Method upon Yield, Purity, and Function

Identification of matrix-bound nanovesicles (MBV) as ubiquitous components of the extracellular matrix (ECM) raises questions regarding their biologic functions and their potential theranostic application. Unlike liquid-phase extracellular vesicles (e.g., exosomes), MBV are tightly bound to the ECM, which makes their isolation and harvesting more challenging. The indiscriminate use of different methods to harvest MBV can alter or disrupt their structural and/or functional integrity. The objective of the present study was to compare the effect of various MBV harvesting methods upon yield, purity, and biologic activity. Combinations of four methods to solubilize the ECM (collagenase [COL], liberase [LIB], or proteinase K [PK] and nonenzymatic elution with potassium chloride) and four isolation methods (ultracentrifugation, ultrafiltration [UF], density barrier, and size exclusion chromatography [SEC]) were used to isolate MBV from urinary bladder-derived ECM. All combinations of solubilization and isolation methods allowed for the harvesting of MBV, however, distinct differences were noted. The highest yield, purity, cellular uptake, and biologic activity were seen with MBV isolated by a combination of liberase or collagenase followed by SEC. The combination of proteinase K and UF was shown to have detrimental effects on bioactivity. The results show the importance of selecting appropriate MBV harvesting methods for the characterization and evaluation of MBV and for analysis of their potential theranostic application. Impact statement Identification of matrix-bound nanovesicles (MBV) as ubiquitous components of the extracellular matrix (ECM) has raised questions regarding their biologic functions and their potential theranostic application. This study demonstrates that the harvesting methods used can result in samples with physical and biochemical properties that are unique to the isolation and solubilization methods used. Consequently, developing harvesting methods that minimize sample contamination with ECM remnants and/or solubilization agents will be essential in determining the theranostic potential of MBV in future studies.

Optimizing the decellularization process of human maxillofacial muscles for facial reconstruction using a detergent-only approach

Trauma, congenital diseases, and cancer resection cause muscle deformities of the human facial muscle. Muscle defects are either treated with local or distal flaps if direct closure is not possible. However, such surgical interventions are limited by donor morbidity and limited tissue availability. Decellularized scaffolds provide alternative strategies for replacing and restoring missing facial muscle by creating scaffolds that mimic the native tissue. This study aimed to develop a protocol to decellularize human zygomaticus major muscle (ZMM) and masseter muscle (MM). Three protocols were assessed including a detergent-only treatment (DOT), detergent-enzymatic treatment (DET) protocol, and a third nondetergent nonenzymatic treatment protocol. Scaffolds were then characterized via histological, immunofluorescent, and quantitative techniques to assess which protocol provided optimal decellularization and maintenance of the extracellular matrix (ECM). The results demonstrated three cycles of DOT protocol consisting of 2% sodium dodecyl sulfate for 4 hr was optimal for decellularization for both ZMM and MM. After three cycles, DNA content was significantly reduced compared with native ZMM and MM (p < .05) with preservation of collagen and glycosaminoglycan content and ECM on histological analysis. DET and nondetergent nonenzymatic treatment protocols were unsuccessful in decellularizing the ZMM and MM with residual DNA content after four cycles and caused ECM disruption on histological analysis. All protocols did not impair the mechanical properties and supported human fibroblast growth. In conclusion, the DOT protocol is effective in producing human decellularized muscle scaffolds that maintain the ECM. Further investigation of detergent only decellurization techniques should be explored as a first step to create effective scaffolds for muscle tissue engineering.

M. leprae interacts with the human epidermal keratinocytes, neonatal (HEKn) via the binding of laminin-5 with α-dystroglycan, integrin-β1, or -β4

Although Mycobacterium leprae (M.leprae) is usually found in macrophages and nerves of the dermis of patients with multibacillary leprosy, it is also present in all layers of the epidermis, basal, suprabasal, prickle cells, and keratin layers. However, the mechanism by which M.leprae invades the dermis remains unknown, whereas the underlying mechanism by which M.leprae invades peripheral nerves, especially Schwann cells, is well defined. M. leprae binds to the α-dystroglycan (DG) of Schwann cells via the interaction of α-DG and laminin (LN) -α2 in the basal lamina, thus permitting it to become attached to and invade peripheral nerves. In the current study, we investigated the issue of how M.leprae is phagocytosed by human epidermal keratinocytes, neonatal (HEKn). LN-5 is the predominant form of laminin in the epidermis and allows the epidermis to be stably attached to the dermis via its interaction with α/β-DG as well as integrins that are produced by keratinocytes. We therefore focused on the role of LN-5 when M. leprae is internalized by HEKn cells. Our results show that M.leprae preferentially binds to LN-5-coated slides and this binding to LN-5 enhances its binding to HEKn cells. The findings also show that pre-treatment with an antibody against α-DG, integrin-β1, or -β4 inhibited the binding of LN-5-coated M.leprae to HEKn cells. These results suggest that M. leprae binds to keratinocytes by taking advantage of the interaction of LN-5 in the basal lamina of the epidermis and a surface receptor of keratinocytes, such as α-DG, integrin-β1, or -β4.