MMP inhibition as a novel strategy for extracellular matrix preservation during whole liver decellularization.

As the only reliable treatment option for end-stage liver diseases, conventional liver transplantation confronts major supply limitations. Accordingly, the decellularization of discarded livers to produce bioscaffolds that support recellularization with progenitor/stem cells has emerged as a promising translational medicine approach. The success of this approach will substantially be determined by the extent of extracellular matrix (ECM) preservation during the decellularization process. Here, we assumed that the matrix metalloproteinase (MMP) inhibition could reduce the ECM damage during the whole liver decellularization of an animal model using a perfusion-based system. We demonstrated that the application of doxycycline as an MMP inhibitor led to significantly higher preservation of collagen, glycosaminoglycans, and hepatic growth factor (HGF) contents, as well as mechanical and structural features, including tensile strength, fiber integrity, and porosity. Notably, produced bioscaffolds were biocompatible and efficiently supported cell viability and proliferation in vitro. We also indicated that produced bioscaffolds efficiently supported HepG2 cell function upon seeding onto liver ECM discs using albumin and urea assay. Additionally, MMP inhibitor pretreated decellularized livers were more durable in contact with collagenase digestion compared to control bioscaffolds in vitro. Using zymography, we confirmed the underlying mechanism that results in these promising effects is through the inhibition of MMP2 and MMP9. Overall, we demonstrated a novel method based on MMP inhibition to ameliorate the ECM structure and composition preservation during liver decellularization as a critical step in fabricating transplantable bioengineered livers.

Integrated bioinformatics and wet-lab analysis revealed cell adhesion prominent genes CDC42, TAGLN and GSN as prognostic biomarkers in colonic-polyp lesions.

Colorectal cancers are derived from intestinal polyps. Normally, alterations in cell adhesion genes expression cause deviation from the normal cell cycle, leading to cancer development, progression, and invasion. The present study aimed to investigate the elusive expression pattern of CDC42, TAGLN, and GSN genes in patients with high and low-risk polyp samples, and also colorectal cancer patients and their adjacent normal tissues. In upcoming study, 40 biopsy samples from Taleghani Hospital (Tehran, Iran) were collected, consisting of 20 colon polyps and 20 paired adjacent normal tissues. The expression of the nominated genes CDC42, TAGLN, and GSN was analyzed using quantitative polymerase chain reaction (Q-PCR) and relative quantification was determined using the 2-ΔΔCt method. ROC curve analysis was performed to compare high-risk and low-risk polyps for the investigated genes. The expression of adhesion molecule genes was also evaluated using TCGA data and the correlation between adhesion molecule gene expression and immunophenotype was analyzed. The role of mi-RNAs and lncRNAs in overexpression of adhesion molecule genes was studied. Lastly, GO and KEGG were performed to identify pathways related to adhesion molecule genes expression in healthy, normal adjacent, and COAD tissues. The results showed that the expression patterns of these genes were significantly elevated in high-risk adenomas compared to low-risk polyps and normal tissues and were associated with various clinicopathological characteristics. The estimated AUC for CDC42, TAGLN, and GSN were 0.87, 0.77, and 0.80, respectively. The study also analyzed COAD cancer patient data and found that the selected gene expression in cancer patients was significantly reduced compared to high-risk polyps and healthy tissues. Survival analysis showed that while the expression level of the GSN gene had no significant relationship with survival rate, the expression of CDC42 and TAGLN genes did have a meaningful relationship, but with opposite effects, suggesting the potential use of these genes as diagnostic or prognostic markers for colorectal cancer. The present study's findings suggest that the expression pattern of CDC42, TAGLN, and GSN genes was significantly increased during the transformation of normal tissue to polyp lesions, indicating their potential as prognostic biomarkers for colorectal polyp development. Further results provide valuable insights into the potential use of these genes as diagnostic or prognostic markers for colorectal cancer. However, further studies are necessary to validate these findings in larger cohorts and to explore the underlying mechanisms of these genes in the development and progression of colorectal cancer.

Wet-spinnability and crosslinked Fiber properties of alginate/hydroxyethyl cellulose with varied proportion for potential use in tendon tissue engineering.

Researchers have examined different bio-inspired materials in tissue engineering and regenerative medicine to fabricate scaffolds to address tendon regeneration requirements. We developed fibers based on alginate (Alg) and hydroxyethyl cellulose (HEC) by wet-spinning technique to mimic the fibrous sheath of ECM. Various proportions (25:75, 50:50, 75:25) of 1 % Alg and 4 % HEC were blended to this aim. Two steps of crosslinking with different concentrations of CaCl2 (2.5 and 5 %) and glutaraldehyde (2.5 %) were used to improve physical and mechanical properties. The fibers were characterized by FTIR, SEM, swelling, degradation, and tensile tests. The in vitro proliferation, viability, and migration of tenocytes on the fibers were also evaluated. Moreover, the biocompatibility of implanted fibers was investigated in an animal model. The results showed ionic and covalent molecular interactions between the components. In addition, by properly maintaining surface morphology, fiber alignment, and swelling, lower concentrations of HEC in the blending provided good degradability and mechanical features. The mechanical strength of fibers was in the range of collagenous fibers. Increasing the crosslinking led to significantly different mechanical behaviors in terms of tensile strength and elongation at break. Because of good in vitro and in vivo biocompatibility, tenocyte proliferation, and migration, the biological macromolecular fibers could serve as desirable tendon substitutes. This study provides more practical insight into tendon tissue engineering in translational medicine.

Genetic modification and preconditioning strategies to enhance functionality of mesenchymal stromal cells: a clinical perspective.

INTRODUCTION: Mesenchymal stromal cell (MSC)-based therapy has generated great hope for the treatment of various diseases such as myocardial infarction and stroke. Unfortunately, MSC-based therapy faces major hurdles in its translation to clinical practice. To address these issues, preconditioning and genetic modification strategies have been developed. Through preconditioning, MSCs are cultured under sub-lethal conditions of environmental stresses or treated with specific drugs, biomolecules, and growth factors. Genetic modification is a procedure in which specific genetic sequences are transferred into the MSCs via viral vectors or CRISP/Cas9 in order to alter the expression of distinctive genes. AREAS COVERED: In this article, a comprehensive review on preconditioning and gene modification inducers, mechanisms of action, and their impacts were discussed. In addition, clinical trials that used preconditioned and genetic modified MSCs are debated. EXPERT OPINION: Numerous preclinical investigations have demonstrated that preconditioning and genetic modifications considerably enhance MSC's therapeutic capacity through improving their survival rate, antioxidant activity, growth factor secretion, immunomodulation, homing efficiency, and angiogenesis. For MSC preconditioning and genetic modification to achieve clinical translation, remarkable outcomes in clinical trials are of pivotal importance.

Angiogenesis and Re-endothelialization in decellularized scaffolds: Recent advances and current challenges in tissue engineering.

Decellularization of tissues and organs has recently become a promising approach in tissue engineering and regenerative medicine to circumvent the challenges of organ donation and complications of transplantations. However, one main obstacle to reaching this goal is acellular vasculature angiogenesis and endothelialization. Achieving an intact and functional vascular structure as a vital pathway for supplying oxygen and nutrients remains the decisive challenge in the decellularization/re-endothelialization procedure. In order to better understand and overcome this issue, complete and appropriate knowledge of endothelialization and its determining variables is required. Decellularization methods and their effectiveness, biological and mechanical characteristics of acellular scaffolds, artificial and biological bioreactors, and their possible applications, extracellular matrix surface modification, and different types of utilized cells are factors affecting endothelialization consequences. This review focuses on the characteristics of endothelialization and how to optimize them, as well as discussing recent developments in the process of re-endothelialization.

Immunogenicity of decellularized extracellular matrix scaffolds: a bottleneck in tissue engineering and regenerative medicine.

Tissue-engineered decellularized extracellular matrix (ECM) scaffolds hold great potential to address the donor shortage as well as immunologic rejection attributed to cells in conventional tissue/organ transplantation. Decellularization, as the key process in manufacturing ECM scaffolds, removes immunogen cell materials and significantly alleviates the immunogenicity and biocompatibility of derived scaffolds. However, the application of these bioscaffolds still confronts major immunologic challenges. This review discusses the interplay between damage-associated molecular patterns (DAMPs) and antigens as the main inducers of innate and adaptive immunity to aid in manufacturing biocompatible grafts with desirable immunogenicity. It also appraises the impact of various decellularization methodologies (i.e., apoptosis-assisted techniques) on provoking immune responses that participate in rejecting allogenic and xenogeneic decellularized scaffolds. In addition, the key research findings regarding the contribution of ECM alterations, cytotoxicity issues, graft sourcing, and implantation site to the immunogenicity of decellularized tissues/organs are comprehensively considered. Finally, it discusses practical solutions to overcome immunogenicity, including antigen masking by crosslinking, sterilization optimization, and antigen removal techniques such as selective antigen removal and sequential antigen solubilization.

Recent advances on small molecules in osteogenic differentiation of stem cells and the underlying signaling pathways.

Bone-related diseases are major contributors to morbidity and mortality in elderly people and the current treatments result in insufficient healing and several complications. One of the promising areas of research for healing bone fractures and skeletal defects is regenerative medicine using stem cells. Differentiating stem cells using agents that shift cell development towards the preferred lineage requires activation of certain intracellular signaling pathways, many of which are known to induce osteogenesis during embryological stages. Imitating embryological bone formation through activation of these signaling pathways has been the focus of many osteogenic studies. Activation of osteogenic signaling can be done by using small molecules. Several of these agents, e.g., statins, metformin, adenosine, and dexamethasone have other clinical uses but have also shown osteogenic capacities. On the other hand, some other molecules such as T63 and tetrahydroquinolines are not as well recognized in the clinic. Osteogenic small molecules exert their effects through the activation of signaling pathways known to be related to osteogenesis. These pathways include more well-known pathways including BMP/Smad, Wnt, and Hedgehog as well as ancillary pathways including estrogen signaling and neuropeptide signaling. In this paper, we review the recent data on small molecule-mediated osteogenic differentiation, possible adjunctive agents with these molecules, and the signaling pathways through which each small molecule exerts its effects.