Acellular Matrices Research Articles

Proposing Novel Biological Scaffolds for the Regeneration of the Dura Mater

ABSTRACTThe dura mater protects underlying tissues and cerebrospinal fluid, but dural abnormalities can cause leaking and meningitis and wound infections. This review emphasizes the relevance of dural repair and the progress of dural reconstruction materials, focusing on biological scaffolds. A comprehensive assessment of dural substitution literature focused on composite, acellular, natural, synthetic, and homologous materials. Decellularized dura scaffolds as viable natural biomaterials for tissue engineering are explored in this overview of these materials' properties, effectiveness, and therapeutic uses. The evaluation also compares materials and assesses host tissue response in preclinical and clinical studies. The review highlights various dural substitution findings. There is no gold standard for dural repair, despite the variety of materials used. Replicating natural dura mater's mechanical and structural qualities is difficult. Recent research suggests that decellularized dura scaffolds can regenerate tissue while reducing inflammation and transplant rejection. Furthermore, the movement toward personalized medicine in this sector suggests that bespoke alternatives might be chosen depending on patient characteristics, improving treatment effects. Synthesizing dural replacement research and clinical uses in this review adds to knowledge. It tackles standard materials' shortcomings and shows how biological scaffolds might improve dural repair. The analysis opens the door to personalized dural repair research that might enhance patient outcomes and advance neurosurgery. The insights presented herein highlight the intriguing prospects for appropriate dural restorative materials, seeking to improve dural defect treatment.

Current Scenario and Future Perspectives of Porcine Corneal Xenotransplantation.

Corneal diseases represent a significant cause of blindness worldwide, with corneal transplantation being an effective treatment to prevent vision loss. Despite substantial advances in transplantation techniques, the demand for donor corneas exceeds the available supply, particularly in developing countries. Cornea xenotransplantation has emerged as a promising strategy to address the worldwide scarcity, notably using porcine corneas. In addition to the inherent immune privilege of the cornea, the low cost of porcine breeding and the anatomical and physiological similarities between humans and pigs have made porcine corneas a viable alternative. Nonetheless, ethical concerns, specifically the risk of xenozoonotic transmission and the necessity for stringent biosafety measures, remain significant obstacles. Moreover, the success of xenotransplantation is compromised by innate and adaptive immune responses, which requires meticulous consideration and further studies. Despite these challenges, recent breakthroughs have further contributed to reducing immunogenicity while preserving the corneal architecture. Advances in genetic engineering, such as the use of CRISPR-Cas9 to eliminate critical porcine antigens, have shown promise for mitigating immune reactions. Additionally, new immunosuppressive protocols, such as have techniques like decellularization and the use of porcine-derived acellular matrices, have greatly increased graft survival in preclinical models. Future research must focus on refining immunomodulatory strategies and improving graft preparation techniques to ensure the long-term survival and safety of porcine corneal xenotransplantation in clinical trials in humans.

Development and Biocompatibility Assessment of Decellularized Porcine Uterine Extracellular Matrix-Derived Grafts.

Biomaterials derived from biological matrices have been widely investigated due to their great therapeutic potential in regenerative medicine, since they are able to induce cell proliferation, tissue remodeling, and angiogenesis in situ. In this context, highly vascularized and proliferative tissues, such as the uterine wall, present an interesting source to produce acellular matrices that can be used as bioactive materials to induce tissue regeneration. Therefore, this study aimed to establish an optimized protocol to generate decellularized uterine scaffolds (dUT), characterizing their structural, compositional, and biomechanical properties. In addition, in vitro performance and invivo biocompatibility were also evaluated to verify their potential applications for tissue repair. Results showed that the protocol was efficient to promote cell removal, and dUT general structure and extracellular matrix composition remained preserved compared with native tissue. In addition, the scaffolds were cytocompatible, allowing cell growth and survival. In terms of biocompatibility, the matrices did not induce any signs of immune rejection invivo in a model of subcutaneous implantation in immunocompetent rats, demonstrating an indication of tissue integration after 30 days of implantation. In summary, these findings suggest that dUT scaffolds could be explored as a biomaterial for regenerative purposes, which is beyond the studies in the reproductive field.

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

Extracellular matrix-derived scaffolds (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 using 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.

Hierarchically Structured Biodegradable Microspheres Promote Therapeutic Angiogenesis.

Promoting neovascularization is a prerequisite for many tissue engineering applications and the treatment of cardiovascular disease. Delivery of a pro-angiogenic stimulus via acellular materials offers several benefits over biological therapies but has been hampered by interaction of the implanted material with the innate immune response. However, macrophages, a key component of the innate immune response, release a plurality of soluble factors that can be harnessed to stimulate neovascularization and restore blood flow to damaged tissue. This study investigates the ability of biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres to restore tissue perfusion in a hind limb model of ischaemia. Microspheres exhibiting a hierarchical porous structure are associated with an increase in blood flow at day 21 post-implantation compared with solid microspheres composed of the same polymer. This corresponds with an increase in blood vessel density in the surrounding tissue. In vitro simulation of the foreign body response observed demonstrates M2-like macrophages incubated with the porous microspheres secreted increased amounts of vascular endothelial growth factor (VEGF) compared with M1-like macrophages providing a potential mechanism for the increased neovascularization. The results from this study demonstrate implantable biodegradable porous microspheres provide a novel approach for increasing neovascularization that could be exploited for therapeutic applications.

Stem cells, cell therapies, and bioengineering in lung biology and diseases 2023.

Repair and regeneration of a diseased lung using stem cells or bioengineered tissues is an exciting therapeutic approach for a variety of lung diseases and critical illnesses. Over the past decade, increasing evidence from preclinical models suggests that mesenchymal stromal cells, which are not normally resident in the lung, can be used to modulate immune responses after injury, but there have been challenges in translating these promising findings to the clinic. In parallel, there has been a surge in bioengineering studies investigating the use of artificial and acellular lung matrices as scaffolds for three-dimensional lung or airway regeneration, with some recent attempts of transplantation in large animal models. The combination of these studies with those involving stem cells, induced pluripotent stem cell derivatives, and/or cell therapies is a promising and rapidly developing research area. These studies have been further paralleled by significant increases in our understanding of the molecular and cellular events by which endogenous lung stem and/or progenitor cells arise during lung development and participate in normal and pathological remodeling after lung injury. For the 2023 Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases Conference, scientific symposia were chosen to reflect the most cutting-edge advances in these fields. Sessions focused on the integration of "omics" technologies with function, the influence of immune cells on regeneration, and the role of the extracellular matrix in regeneration. The necessity for basic science studies to enhance fundamental understanding of lung regeneration and to design innovative translational studies was reinforced throughout the conference.

Use of three-dimensional acellular collagen matrix in deep or tunnelling diabetic foot ulcers: a retrospective case series.

While most xenograft wound matrices are flat sheets not designed for deep or tunnelling wounds, three-dimensional acellular collagen matrices (3D-ACM) can fill deep wound beds and enable full wound wall apposition. This case series examines the use of 3D-ACM in treating diabetic foot ulcers (DFUs) that are deep, tunnelling, undermining, or irregularly shaped. We report outcomes of cases where 3D-ACM was applied to deep or tunnelling DFUs present for at least four weeks. In this retrospective case series, 3D-ACM was applied, healing was monitored and measurements were collected. Additional 3D-ACM was applied as needed. In total, 11 patients with 13 wounds were treated. Improved wound appearance and reduced size were observed at most follow-ups. Mean initial wound depth was 1.6cm, and several wounds showed significant depth reductions shortly after therapy initiation. In total, 62% of wounds (8/13) reached 50% closure by four weeks. Additionally, 54% (7/13) were fully closed by 12 weeks. The remaining 46% (6/13) took between 12-22.3 weeks to heal. Overall mean therapy time was 13.1 weeks (range: 2.0-22.3 weeks). Deeper wounds generally took longer to close. The findings of this case series showed that 3D-ACM could offer a protective microenvironment for wound management for deep or tunnelling DFUs. While some took >12 weeks to close, this may be attributable to large initial depths and volumes, rather than a failure to respond to the treatment modality. Other wounds that require a conforming 3D matrix, enabling full wound wall apposition, may benefit from 3D-ACM. Further investigations would be beneficial to understand the capabilities of this treatment modality.

The search for an optimal tissue-engineered urethra model for clinical application based on preclinical trials in male animals: A systematic review and meta-analysis.

Tissue engineering has emerged as a promising avenue for reconstructive urology, though only a limited number of tissue-engineered urethral constructs have advanced to clinical testing. Presently, there exists a dearth of agreement regarding the most promising constructs deserving of implementation in clinical practice. The objective of this review was to provide a comprehensive analysis of preclinical trials findings of a tissue-engineered urethra and to identify the most promising constructs for future translation into clinical practice. A systematic search of the Pubmed, Scopus, and PMC databases was conducted in accordance with the PRISMA statement. Manuscripts published in English between 2015 and 2022, reporting on the methodology for creating a tissue-engineered urethra, assessing the regenerative potential of the scaffold in a male animal model, and evaluating the clinical and histological outcomes of treatment, were included. A total of 48 manuscripts met the inclusion criteria, with 12 being eligible for meta-analysis. Meta-analysis revealed no significant benefit of any matrix type in terms of complication rates. However, acellular matrices demonstrated significant advantage over cellular matrices in case of no postoperative stricture formation (odds ratio = 0.06 [95% CI 0.01; 0.23], p < 0.01). Among all subgroups (animal models and scaffold types), the usage of acellular matrices resulted in advantageous effects. The meta-regression analysis did not show a significant impact of defect length (β1 = -0.02 [-0.28; 0.23], p = 0.86). We found that decellularized materials may carry less relevance for urethral reconstruction due to unfavorable preclinical outcomes. Natural polymers, used independently or with synthetic materials, resulted in better postoperative outcomes in animals compared to purely synthetic constructs. Acellular scaffolds showed promising outcomes, matching or exceeding cellular constructs. However, more studies are needed to confirm their clinical effectiveness.

Use of acellular matrices as scaffolds in cartilage regeneration - a systematic review.

Cartilage regeneration remains a significant challenge in the field of regenerative medicine. Acellular matrix-based cartilage tissue regeneration offers an innovative approach to repairing cartilage defects by providing a scaffold for new tissue growth. Its significance lies in its potential to restore joint function, mitigate pain, and improve the quality of life for patients suffering from cartilage-related injuries and conditions. Recent advances in acellular matrix-based cartilage regeneration have focused on enhancing scaffold properties for improved cell adhesion, proliferation, and differentiation. Moreover, several scaffold techniques such as combining ADM and ACM with cartilage tissue, as well as biphasic scaffolding enjoy rising research activity. Incorporating bioactive factors and advanced manufacturing techniques holds promise for producing more biomimetic scaffolds, advancing efficient cartilage repair and regeneration. Obstacles in acellular matrix-based cartilage regeneration include achieving proper integration with surrounding tissue and ensuring long-term durability of the regenerated cartilage. Further, issues such as high costs and limited availability of suitable cells for scaffold seeding must be considered. The heterogeneity and limited regenerative capabilities of cartilage need to be addressed for successful clinical translation. Research should focus on exploring advanced biomaterials and developing new techniques, regarding easily reproductible scaffolds, ideally constructed from clinically validated and readily available commercial products. Findings underline the potential of AM-based approaches, especially rising exploration of tissue-derived ADM and ACM. In future, the primary objective should not only be the regeneration of small cartilage defects, but rather focus on fully regenerating a joint or larger cartilage defect.

Assessing the effects of bladder decellularization protocols on extracellular matrix (ECM) structure, mechanics, and biology

Acellular matrices have historically been applied as biologic scaffolds in surgery, wound care, and tissue engineering, albeit with inconsistent outcomes. One aspect that varies widely between products is the selection of decellularization protocol, yet few studies assess comparative effectiveness of these protocols in preserving mechanics, and protein content. This study characterizes bladder acellular matrix (BAM) using two different detergent and enzymatic protocols, evaluating effects on nuclei and DNA removal (≥90%), structure, tensile properties, and maintenance of extracellular matrix proteins. Porcine bladders were decellularized with 0.5% Sodium Dodecyl Sulfate (SDS) or 0.25% Trypsin-hypotonic-Triton X-100 hypertonic (TT)-based agitation protocols, followed by DNase/RNase agents. Characterization of BAM included decellularization efficacy (DAPI, DNA quantification), structure (histology and scanning electron microscopy), tensile testing (Instron 345C-1 mechanical tester), and protein presence and diversity (mass spectrometry). SDS and TT data was directly compared to the same native bladder using two-tailed paired t-tests. Native, TT, and SDS cohorts for tensile testing were compared using one-way ANOVA; Tukey's post-hoc tests for among group differences. Effective nuclei removal was achieved by SDS- and TT-based protocols. However, target DNA removal was achieved with SDS but not TT. SDS more effectively maintained qualitative tissue architecture compared to TT. The tensile modulus of the TT cohort increased, and stretchability decreased after decellularization in both SDS and TT. UTS was unaffected by either protocol. Higher overall diversity and quantity of core matrisome and matrisome-associated proteins was maintained in the SDS vs TT cohort post-decellularization. The results indicated that detergent selection affects multiple aspects of the resultant BAM biologic product. In the selected protocols, SDS was superior to TT efficacy, and maintenance of gross tissue architecture as well as maintenance of ECM proteins. Decellularization increased scaffold resistance to deformation in both cohorts. Future studies applying biologic scaffolds must consider the processing method and agents used to ensure that materials selected are optimized for characteristics that will facilitate effective translational use.

Hybrid Materials for Vascular Applications: A Preliminary In Vitro Assessment.

The production of biomedical devices able to appropriately interact with the biological environment is still a great challenge. Synthetic materials are often employed, but they fail to replicate the biological and functional properties of native tissues, leading to a variety of adverse effects. Several commercial products are based on chemically treated xenogeneic tissues: their principal drawback is due to weak mechanical stability and low durability. Recently, decellularization has been proposed to bypass the drawbacks of both synthetic and biological materials. Acellular materials can integrate with host tissues avoiding/mitigating any foreign body response, but they often lack sufficient patency and impermeability. The present paper investigates an innovative approach to the realization of hybrid materials that combine decellularized bovine pericardium with polycarbonate urethanes. These hybrid materials benefit from the superior biocompatibility of the biological tissue and the mechanical properties of the synthetic polymers. They were assessed from physicochemical, structural, mechanical, and biological points of view; their ability to promote cell growth was also investigated. The decellularized pericardium and the polymer appeared to well adhere to each other, and the two sides were distinguishable. The maximum elongation of hybrid materials was mainly affected by the pericardium, which allows for lower elongation than the polymer; this latter, in turn, influenced the maximum strength achieved. The results confirmed the promising features of hybrid materials for the production of vascular grafts able to be repopulated by circulating cells, thus, improving blood compatibility.

Decellularized tissue exhibits large differences of extracellular matrix properties dependent on decellularization method: novel insights from a standardized characterization on skeletal muscle

Decellularized matrices are an attractive choice of scaffold in regenerative medicine as they can provide the necessary extracellular matrix (ECM) components, signals and mechanical properties. Various detergent-based protocols have already been proposed for decellularization of skeletal muscle tissue. However, a proper comparison is difficult due to differences in species, muscle origin and sample sizes. Moreover, a thorough evaluation of the remaining acellular matrix is often lacking. We compared an in-house developed decellularization protocol to four previously published methods in a standardized manner. Porcine skeletal muscle samples with uniform thickness were subjected to in-depth histological, ultrastructural, biochemical and biomechanical analysis. In addition, 2D and three-dimensional cytocompatibility experiments were performed. We found that the decellularization methods had a differential effect on the properties of the resulting acellular matrices. Sodium deoxycholate combined with deoxyribonuclease I was not an effective method for decellularizing thick skeletal muscle tissue. Triton X-100 in combination with trypsin, on the other hand, removed nuclear material but not cytoplasmic proteins at low concentrations. Moreover, it led to significant alterations in the biomechanical properties. Finally, sodium dodecyl sulphate (SDS) seemed most promising, resulting in a drastic decrease in DNA content without major effects on the ECM composition and biomechanical properties. Moreover, cell attachment and metabolic activity were also found to be the highest on samples decellularized with SDS. Through a newly proposed standardized analysis, we provide a comprehensive understanding of the impact of different decellularizing agents on the structure and composition of skeletal muscle. Evaluation of nuclear content as well as ECM composition, biomechanical properties and cell growth are important parameters to assess. SDS comes forward as a detergent with the best balance between all measured parameters and holds the most promise for decellularization of skeletal muscle tissue.

Development of Crystalline Corneal Opacities (Steroid Keratopathy) in Dogs After Treatment With Ophthalmic Corticosteroids.

To retrospectively evaluate and describe the relationship between the use of topical corticosteroids and the development of crystalline corneal opacities (steroid keratopathy) in a colony of research Beagles and Beagle-derived dogs. Medical records of 73 purpose-bred Beagles and Beagle-derived dogs were reviewed from June 2012 to May 2021. All dogs were treated with topical ophthalmic corticosteroids for at least 21 days. In addition to regular ophthalmic examination, some dogs also had a systemic lipid profile (n = 6) performed to work up further and characterize the crystalline corneal opacities. Globes of 3 dogs were examined histopathologically. Axial stromal crystalline corneal opacities were appreciated in 25 eyes of 14 dogs after a median of 141 days after initiating treatment (35-396 days). Multiple corticosteroids were used, including neomycin-polymyxin b-dexamethasone 0.1% ophthalmic ointment, prednisolone acetate 1% ophthalmic suspension, and difluprednate 0.05% ophthalmic emulsion (Durezol). Resolution of corneal opacity was documented in 4 of 25 eyes when ophthalmic corticosteroids were discontinued after a median of 406.5 days (271-416 days). Histopathologic examination revealed a dense band of acellular material, poorly staining with periodic acid-Schiff, subtending the corneal epithelium, and being surrounded by spindle cells. This case series documents the onset of steroid keratopathy in Beagles and Beagle-derived dogs after treatment with ophthalmic corticosteroids. Clinical resolution of steroid keratopathy lesions may be possible after discontinuation of ophthalmic corticosteroids.

Soft Tissue Substitutes in Periodontal and Peri-Implant Soft Tissue Augmentation: A Systematic Review.

Different extracellular matrix (ECM)-based technologies in periodontal and peri-implant soft tissue augmentation have been proposed in the market. The present review compared the efficacy of soft tissue substitutes (STSs) and autogenous free gingival grafts (FGGs) or connective tissue grafts (CTGs) in mucogingival procedures to increase keratinized tissue (KT) width around teeth and implants. Two independent examiners performed an electronic search on MEDLINE and the Cochrane Library based on the following PICOS format: (P) adult patients; (I) soft tissue substitutes and FGGs/CTGs; (C) STSs vs. CTGs; STSs vs. FGGs; STSs vs control; (O) KT width gain; (S) systematic reviews, randomized controlled trials. Studies published before November 2023 were included. Around teeth, all biomaterials showed superior performance compared to a coronally advanced flap (CAF) alone for treating gingival recessions. However, when compared to CTGs, acellular dermal matrices (ADMs) yield the most similar outcomes to the gold standard (CTGs), even though in multiple recessions, CTGs continue to be considered the most favorable approach. The use of STSs (acellular matrix or tissue-engineered) in combination with apically positioned flaps (APF) resulted in significantly less gain in KT width compared to that achieved with FGGs and APFs. Around dental implants, free gingival grafts were deemed more effective than soft tissue substitutes in enhancing keratinized mucosa width. Based on the available evidence, questions remain about the alternative use of soft tissue substitutes for conventional grafting procedures using free gingival grafts or connective tissue grafts around teeth and implants.

A hospital-based study of prostate biopsy results in Indian males.

The prostate is a gland belonging to the male reproductive system. Aging results in the dysfunction of the prostate that may present as inflammation, enlargement, and cancer. Additionally, the diseases of the prostate including cancers are slow in progression, and therefore, it is difficult to diagnose them early. Hence, it is increasingly important for physicians to recommend histopathological examination of the prostate gland to identify, manage, and treat prostate cancers. This study was conducted to assess prostate diseases among biopsy specimen collected from patients with signs of prostate diseases. This prospective study was conducted in the Department of Pathology, Deccan College of Medical Sciences, Owaisi Hospital, Hyderabad, between June 2012 and September 2014. All gross specimens (n = 300) of the prostate such as the needle biopsies of the prostate, transurethral resection of the prostate (TURP) chips, and excised specimens of the prostate were included in the study. Histopathological examinations of the biopsies were performed for nuclear size, chromatin material, nucleoli, membrane thickness, irregularity, cytoplasmic granularity, staining, and cell border conspicuity. The biopsies were also assessed for lobule formation, secretions, polymorphonuclear leukocytes, lymphocytes, macrophages, connective tissue stromal cells, their arrangements, and acellular connective tissue material. Of 300 total prostatic biopsies performed, 56 (18.66%) were identified as inflammatory lesions of the prostate (prostatitis), 98 (32.66%) revealed benign prostatic lesions (benign prostatic hyperplasia (BPH)), 112 (37.33%) were identified as BPH with premalignant lesions, and 34 (11.33%) were revealed as malignant tumors of the prostate. Chronic prostatitis (67.85%) was the common inflammatory lesion. The majority (91.42%) revealed epithelial lesions compared to stromal lesions (08.58%). BPH was predominantly (28.00%) noticed among patients in the age group of 61-70 years. Prostatic intraepithelial neoplasia (PIN) was observed majorly (53.35%) in the age group of 61-70 years. Most of the prostatic cancers were identified as adenocarcinomas. However, three variants were also categorized as small cell carcinoma, signet ring cell carcinoma, and transitional cell carcinomas. The results reveal that prostatic adenocarcinomas are predominant among the study population. Additionally, prostatic diseases including cancer are commonly noticed among people belonging to the age group of 61-70 years. More than one-third of patients showed BPH with premalignant lesions, and a majority of the study population showed evidence of chronic prostatitis.

Comparative evaluation of two different xenogenic acellular matrices on full-thickness skin wound healing.

The purpose of the study was to compare the healing potential of bubaline small intestinal matrix (bSIM) and fish swim bladder matrix (FSBM) on full-thickness skin wounds in rabbits. Four full-thickness skin wounds (each 20×20mm) were created on the dorsum of 18 rabbits that were divided into three groups based on treatment: untreated sham control (I), implanted with double layers of bSIM (II) and implanted with double layers of FSBM (III). Macroscopic, immunologic and histologic observations were made to evaluate wound healing. Gross healing progression in the bSIM and FSBM groups showed significantly (p<0.05) less wound contraction compared with the sham group. The IgG concentration in rabbit sera was significantly (p<0.05) lower in the FSBM group compared with the bSIM group by enzyme-linked immunosorbent assay. The stimulation index of peripheral blood lymphocytes was significantly (p<0.05) lower in the FSBM group compared with the bSIM group by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Implantation of FSBM resulted in improved re-epithelialisation, neovascularisation and fibroplasia. The FSBM is a more effective dermal substitute when compared with the bSIM for full-thickness skin wound repair in rabbit.

A High-biocompatibility Interface for the Breast Implant: First Report of a Novel Biological Matrix-assisted Technique in Aesthetic Revision Surgery.

Development of human-compatible tissues is an active field of research that is leading to the production of optimized biological scaffolds to support regenerative medicine. Xenogenic acellular matrices are known to have strongly influenced the field of breast surgery, playing an integral role in wound healing and in preventing the foreign body reaction to silicone implants. Here, we present our experience in using a biological matrix for aesthetic revision surgery with malposition and severe capsular contracture. Revisions were performed using the new MASQUE equine acellular-pericardium-matrix (APM) as an anterior cover for the synthetic prosthesis. Acting as an internal support, the thin APM layer provides a biological and biocompatible interface between the synthetic implant and living tissues, exerting a protective function against fibrotic responses and capsular contracture. The role of an APM in matrix-assisted mammoplasty has yet to be fully established. Our early experience of APM-assisted aesthetic revision surgery shows promising results, laying the foundations for equine biological matrices as a valid tool for the management of capsular contracture-susceptible patients.

Trilayer composite scaffold for urethral reconstruction:in vitroevaluation of mechanical, biological, and angiogenic properties.

Regeneration of damaged urethral tissue remains a major challenge in the field of lower urinary tract reconstruction. To address this issue, various synthetic and natural biodegradable biomaterials are currently being explored for the fabrication of scaffolds that promote urethral regeneration and healing. In this study, we present an approach to fabricate a trilayer hybrid scaffold comprising a central layer of poly(lactic acid) (PLA) between two layers of chitosan. The chitosan/PLA/chitosan (CPC) scaffolds were fabricated by a sequential electrospinning process and their properties were evaluated for their suitability for urethral tissue engineering. The physical and biological properties of the CPC scaffolds were evaluated in comparison to electrospun PLA scaffolds and acellular dermis (Alloderm) as controls for a synthetic and a natural scaffold, respectively. Compared to the controls, the CPC scaffolds exhibited higher elastic modulus and ultimate tensile strength, while maintaining extensibility and suture retention strength appropriate for clinical use. The CPC scaffolds displayed significant hydrophilicity, which was associated with a higher water absorption capacity of the chitosan nanofibres. The degradation products of the CPC scaffolds did not exhibit cytotoxicity and promoted wound closure by fibroblastsin vitro. In addition, CPC scaffolds showed increased growth of smooth muscle cells, an essential component for functional regeneration of urethral tissue. Furthermore, in a chicken embryo-based assay, CPC scaffolds demonstrated significantly higher angiogenic potential, indicating their ability to promote vascularisation, a crucial aspect for successful urethral reconstruction. Overall, these results suggest that CPC hybrid scaffolds containing both natural and synthetic components offer significant advantages over conventional acellular or synthetic materials alone. CPC scaffolds show promise as potential candidates for further research into the reconstruction of the urethrain vivo.

Preparation of Decellularized Amniotic Membrane and Adipose-Derived Stromal/Stem Cell Seeding.

Amniotic membrane, being part of the placenta, is discarded as medical waste after childbirth. It can be decellularized to convert it into an acellular material while retaining the extracellular matrix. Such amniotic membrane grafts support stem cell adhesion, growth, and proliferation. These properties make it a useful candidate to be used as a bio-scaffold in regenerative medicine. This chapter describes a method for the decellularization of the amniotic membrane. Furthermore, the method for seeding adipose-derived stem cells on the decellularized amniotic membrane is described.

Nano-enabled dynamically responsive living acellular hydrogels.

As a key building block of mammalian tissues, extracellular matrices (ECMs) stiffen under shear deformation and undergo cell-imparted healing after damage, features that regulate cell fate, communication, and survival. The shear-stiffening behavior is attributed to semi-flexible biopolymeric ECM networks. Inspired by the mechanical behavior of ECMs, we develop acellular nanocomposite living hydrogels (LivGels), comprising network-forming biopolymers and anisotropic hairy nanoparticle linkers that mimic the dynamic mechanical properties of living counterparts. We show that a bifunctional dynamic linker nanoparticle (nLinker), bearing semi-flexible aldehyde- and carboxylate-modified cellulose chains attached to rigid cellulose nanocrystals converts bulk hydrogels to ECM-like analogues via ionic and dynamic covalent hydrazone bonds. The nLinker not only enables the manipulation of nonlinear mechanics and stiffness within the biological window, but also imparts self-healing to the LivGels. This work is a step forward in designing living acellular soft materials with complex dynamic properties using bio-based nanotechnology.