A transient apical extracellular matrix relays cytoskeletal patterns to shape permanent acellular ridges on the surface of adult C. elegans

Apical extracellular matrices can form protruding structures such as denticles, ridges, scales, or teeth on the surfaces of epithelia. The mechanisms that shape these structures remain poorly understood. Here, we show how the actin cytoskeleton and a provisional matrix work together to sculpt acellular longitudinal alae ridges in the cuticle of adult C. elegans. Transient actomyosin-dependent constriction of the underlying lateral epidermis accompanies deposition of the provisional matrix at the earliest stages of alae formation. Actin is required to pattern the provisional matrix into longitudinal bands that are initially offset from the pattern of longitudinal actin filaments. These bands appear ultrastructurally as alternating regions of adhesion and separation within laminated provisional matrix layers. The provisional matrix is required to establish these demarcated zones of adhesion and separation, which ultimately give rise to alae ridges and their intervening valleys, respectively. Provisional matrix proteins shape the alae ridges and valleys but are not present within the final structure. We propose a morphogenetic mechanism wherein cortical actin patterns are relayed mechanically to the laminated provisional matrix to set up distinct zones of matrix layer separation and accretion that shape a permanent and acellular matrix structure.

Characterization of Composite Nano-Bioscaffolds Based on Collagen and Supercritical Fluids-Assisted Decellularized Fibrous Extracellular Matrix

Nano-bioscaffolds obtained from decellularized tissues have been employed in several medical applications. Nano-bioscaffolds could provide structural support for cell attachment and a suitable environment with sufficient porosity for cell growth and proliferation. In this study, a new combined method constitutes a decellularization protocol to remove the tissue and cellular molecules from porcine dermis for preparation of nano-bioscaffolds with fibrous extracellular matrix via pre- and post-treatment of supercritical fluids. The supercritical fluids-assisted nano-bioscaffolds were characterized by peptide identification, infrared spectrum of absorption, morphology, histological observations, DNA quantification, and hemocompatibility. Further, the resulting nano-bioscaffolds could be employed to obtain new cross-linked composite nano-bioscaffold containing collagen and acellular matrix.

Smart Bio-Polymeric Matrix for Accelerated Wound Healing and Tissue Regeneration

Traditionally in Chinese medicine, animal sources and their by-products widely used for surgical and healing purposes. Eggshell Membrane (ESM) has been potentially used as grafting material for wound covering and healing due to its fibrous mesh enriched with collagen and glycoproteins. However, the fragile nature of ESM limits applicability for small and superficial wounds. Therefore, acellular matrix/scaffold fabricated from the allogeneic or xenogeneic tissues widely used as grafting material for the repairing and regeneration tissue. Here, we modified an acellular scaffold in different concentrations of ESM protein (ESMP)-5, 7.5 and 10%, and studied synergistic effect for intensifying the tissue healing and regeneration process. Modified Scaffolds (ESMP-AGDS) were evaluated for tissue regeneration by subjecting it through physicochemical and biological characterization i.e., biochemical assay, FTIR, FESEM, in vitro and in vivo analysis. The study revealed proper interaction between the ESMP and acellular matrix 3D interconnected pores structure (57.69±15.65 μm) with good porosity (60.56±9.78%) for better cell and nutrient diffusion. In vitro studies revealed good biodegradability and biocompatibility of modified scaffold with 3T3 mouse fibroblast cells. At the very least concentration of 5% ESMP, acellular matrix showed excellent proliferation and attachment of fibroblast with the progression of time. Similarly, in vivo study showed a full-thickness excisional wound in the albino mice model healed within 14 days along with hair follicles regenerated neo-skin tissue, without any immunogenicity and inflammation. Thus, the study confirmed ESMP and acellular matrix synergistic effect results in a cost-effective, biodegradable, biocompatible smart material potentially applicable for tissue regeneration.

Electrospun PLGA and PLGA/gelatin scaffolds for tubularized urethral replacement: Studies in vitro and in vivo

To investigate the biocompatibility of polylactic acid-glycolic acid copolymer (PLGA) and PLGA/gelatin scaffolds and their suitability for tubular urethral replacement in a canine model. PLGA and PLGA/gelatin scaffolds was constructed by electrospinning. Microstructural differences between the scaffolds was examined by Scanning electron microscopy (SEM) followed by mechanical properties testing. Biocompatibility of the material was evaluated using SEM 4, 8, 12 and 72 h after PLGA and PLGA/gelatin scaffolds co-culture with urothelial cells. And confocal analysis was also used to showed the cell adhesive and growth at 12 h. Approximately 2 cm of the anterior urethra of twelve dogs were removed and replaced with a scaffold. After the surgery for 1 month performed urethrography and for 3 month perform hematoxylin–eosin (H&E) and Masson. The results indicated that PLGA and PLGA/gelatin scaffolds had a void microfilament structure, similar to that of normal acellular matrix tissue. And the tensile strength was decreased whereas the tensile deformation and suture retention strength was increased in PLGA/gelatin scaffolds compared to that in PLGA scaffolds Urothelial cells grew well on both scaffolds. Postoperatively, animals recovered well and urinated spontaneously. However, urethrography showed varying degrees of urethral strictures in the reconstructed urethras. H&E and Masson showed that multilayer urothelial cells were formed in both the proximal and distal segments of the reconstructed urethras but without continuity. There was a small amount of smooth muscle and blood vessels under the epithelium, but regenerative urothelial cells at the midpoint of the reconstructed segment did not continue. Lots of lymphocyte infiltration was observed under the epithelium, some collagen tissue was deposited under the neo-urethral epithelium were observed. In conclusion, PLGA and PLGA/gelatin scaffolds are not suitable for tubularized urethral replacement in the canine model.

REPAIR OF ABDOMINAL WALL DEFECTS WITH ACELLULAR BOVINE PERICARDIUM MATRIX - A MULTICENTER PROSPECTIVE STUDY

Background: The association of prosthetic meshes in the abdominal wall repair , reducing the recurrence rates in an impactful way, has become an almost mandatory routine for the success of these surgeries. After decades using non-biological synthetic implants, from the 90s onwards biological acellular membranes of animal or human origin were introduced , beginning a new era in abdominal wall defects correction . Methods: Thirty patients underwent repair for different abdominal wall deformities, with acellular matrices of bovine pericardium, in a total of 40 anatomically individualized implants. The median follow-up was 22 months, with patients evaluated clinically and radiologically. In three cases, biopsies of the implanted areas were performed, allowing histological analysis of the material. Results: There was no recurrence of hernias in any of the cases, both clinically and radiologically. There was also no record of hematomas, infections or any phenomenon of a local or systemic reaction nature. Radiologically, it was not possible to visualize the matrices at the implantation site in any of the analysed postoperative periods. Biopsies showed important tissue neoformation replacing the implanted membranes, with important deposition of collagen, normal-looking cellularized tissue, and absence of foreign body reactions. Conclusions: The analysed matrices showed similarity to other biological membranes described in the international literature. Representing an important update and conceptual evolution, biological matrices must be incorporated into the therapeutic arsenal in abdominal wall repairs. Key Words: Biological prosthetic mesh; Biological acellular matrix; Acellular bovine pericardium matrix; Abdominal hernia; Ventral hernia repair;