Bioactive polymeric materials and electrical stimulation strategies for musculoskeletal tissue repair and regeneration

Polypyrrole (PPy) is a promising conducting polymer in bone regeneration; however, due to the biological inertia of the PPy surface, it has poor cell affinity and bioactivity. Based on the excellent adhesion capacity, biocompatibility, and bioactivity of polydopamine (PDA), the PDA is used as a functional coating in tissue repair and regeneration. Herein, we used a two-step method to construct a functional conductive coating of polypyrrole/polydopamine (PPy/PDA) nanocomposite for bone regeneration. PPy nanowires (NWs) are used as the morphologic support layer, and a layer of highly bioactive PDA is introduced on the surface of PPy NWs by solution oxidation. By controlling the depositing time of PDA within 5 h, the damage of nano morphology and conductivity of the PPy NWs caused by the coverage of PDA deposition layer can be effectively avoided, and the thin PDA layer also significantly improve the hydrophilicity, adhesion, and biological activity of PPy NWs coating. The PPy/PDA NWs coating performs better biocombaitibility and bioactivity than pure PPy NWs and PDA, and has benefits for the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells cultured on the surface. In addition, PPy/PDA NWs can significantly promote the osteogenesis of MC3T3-E1 in combination with micro galvanostatic electrical stimulation (ES).

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Signals and Mechanisms Regulating Monocyte and Macrophage Activation in the Pathogenesis of Juvenile Idiopathic Arthritis

International Journal of Molecular Sciences ◽

10.3390/ijms22157960 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7960

Author(s):

Chao-Yi Wu ◽

Huang-Yu Yang ◽

Jing-Long Huang ◽

Jenn-Haung Lai

Keyword(s):

Juvenile Idiopathic Arthritis ◽

Innate Immune System ◽

Tissue Repair ◽

Macrophage Activation ◽

Cell Activation ◽

Innate Immune ◽

Inflammatory Joint Diseases ◽

Tissue Repair And Regeneration ◽

Related Cell ◽

Key Players

Monocytes (Mos) and macrophages (Mφs) are key players in the innate immune system and are critical in coordinating the initiation, expansion, and regression of many autoimmune diseases. In addition, they display immunoregulatory effects that impact inflammation and are essential in tissue repair and regeneration. Juvenile idiopathic arthritis (JIA) is an umbrella term describing inflammatory joint diseases in children. Accumulated evidence suggests a link between Mo and Mφ activation and JIA pathogenesis. Accordingly, topics regarding the signals and mechanisms regulating Mo and Mφ activation leading to pathologies in patients with JIA are of great interest. In this review, we critically summarize recent advances in the understanding of how Mo and Mφ activation is involved in JIA pathogenesis and focus on the signaling pathways and mechanisms participating in the related cell activation processes.

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Repair cell first, then regenerate the tissues and organs

Military Medical Research ◽

10.1186/s40779-021-00297-5 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Xiao-Bing Fu

Keyword(s):

Tissue Repair ◽

Cell Damage ◽

Ischemia Reperfusion ◽

Severe Trauma ◽

Basic Unit ◽

Basic Process ◽

Tissue Repair And Regeneration ◽

Healing Tissue ◽

Organ Repair ◽

And Function

AbstractWound healing, tissue repair and regenerative medicine are in great demand, and great achievements in these fields have been made. The traditional strategy of tissue repair and regeneration has focused on the level of tissues and organs directly; however, the basic process of repair at the cell level is often neglected. Because the cell is the basic unit of organism structure and function; cell damage is caused first by ischemia or ischemia-reperfusion after severe trauma and injury. Then, damage to tissues and organs occurs with massive cell damage, apoptosis and even cell death. Thus, how to achieve the aim of perfect repair and regeneration? The basic process of tissue or organ repair and regeneration should involve repair of cells first, then tissues and organs. In this manuscript, it is my consideration about how to repair the cell first, then regenerate the tissues and organs.

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Interactome Analysis of iPSC Secretome and Its Effect on Macrophages In Vitro

International Journal of Molecular Sciences ◽

10.3390/ijms22020958 ◽

2021 ◽

Vol 22 (2) ◽

pp. 958

Author(s):

Luca Tamò ◽

Kleanthis Fytianos ◽

Fabienne Caldana ◽

Cedric Simillion ◽

Anis Feki ◽

...

Keyword(s):

Tissue Repair ◽

Mononuclear Cells ◽

Human Peripheral Blood ◽

Critical Role ◽

Organ Injury ◽

Macrophage Phenotype ◽

Gene Interaction Network ◽

Tissue Repair And Regeneration ◽

Secretory Pattern

Induced pluripotent stem cell secretome (iPSC-CM) mitigate organ injury and help in repair. Macrophages play a critical role in tissue repair and regeneration and can be directed to promote tissue repair by iPSC-CM, although the exact mechanisms are not known. In the current investigative study, we evaluated the possible mechanism by which iPSC-CM regulates the phenotype and secretory pattern of macrophages in vitro. Macrophages were obtained from human peripheral blood mononuclear cells and differentiated to various subpopulations and treated with either iPSC-CM or control media in vitro. Macrophage phenotype was assessed by flow cytometry, gene expression changes by qRT PCR and secretory pattern by multiplex protein analysis. The protein and gene interaction network revealed the involvement of Amyloid precursor protein (APP) and ELAV-like protein 1 (ELAVL-1) both present in the iPSC-CM to play an important role in regulating the macrophage phenotype and their secretory pattern. This exploratory study reveals, in part, the possible mechanism and identifies two potential targets by which iPSC-CM regulate macrophages and help in repair and regeneration.

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The Cross-Talk between Mesenchymal Stem Cells and Immune Cells in Tissue Repair and Regeneration

International Journal of Molecular Sciences ◽

10.3390/ijms22052472 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2472

Author(s):

Carl Randall Harrell ◽

Valentin Djonov ◽

Vladislav Volarevic

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Immune Cells ◽

Tissue Repair ◽

Molecular Mechanisms ◽

Current Knowledge ◽

Multipotent Stem Cells ◽

Tissue Repair And Regeneration ◽

Almost All ◽

And Function

Mesenchymal stem cells (MSCs) are self-renewable, rapidly proliferating, multipotent stem cells which reside in almost all post-natal tissues. MSCs possess potent immunoregulatory properties and, in juxtacrine and paracrine manner, modulate phenotype and function of all immune cells that participate in tissue repair and regeneration. Additionally, MSCs produce various pro-angiogenic factors and promote neo-vascularization in healing tissues, contributing to their enhanced repair and regeneration. In this review article, we summarized current knowledge about molecular mechanisms that regulate the crosstalk between MSCs and immune cells in tissue repair and regeneration.

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Design of epidermal growth factor immobilization on 3D biocompatible scaffolds to promote tissue repair and regeneration

Scientific Reports ◽

10.1038/s41598-021-81905-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Teodora Bavaro ◽

Sara Tengattini ◽

Refaya Rezwan ◽

Enrica Chiesa ◽

Caterina Temporini ◽

...

Keyword(s):

Growth Factor ◽

Epidermal Growth Factor ◽

Tissue Repair ◽

Peptide Mapping ◽

Rnase A ◽

Fibroblast Cells ◽

Native State ◽

Tissue Repair And Regeneration ◽

Epidermal Growth ◽

Cell Proliferative Activity

AbstractExogenous application of human epidermal growth factor (hEGF) stimulates epidermal wound healing. The aim of this study was to develop bioconjugates based on hEGF mimicking the protein in its native state and thus suitable for tissue engineering applications, in particular for treating skin-related disorders as burns. Ribonuclease A (RNase A) was used to investigate a number of different activated-agarose carriers: cyanogen bromide (CNBr)-activated-agarose and glyoxyl-agarose showed to preserve the appropriate orientation of the protein for receptor binding. EGF was immobilized on these carriers and immobilization yield was evaluated (100% and 12%, respectively). A peptide mapping of unbound protein regions was carried out by LC–MS to take evidence of the residues involved in the immobilization and, consequently, the flexibility and surface accessibility of immobilized EGF. To assess cell proliferative activities, 10, 25, 50, and 100 ng/mL of each immobilized EGF sample were seeded on fibroblast cells and incubated for 24, 48 and 72 h. The immobilized growth factor showed significantly high cell proliferative activity at 50 and 100 ng/mL compared to control and soluble EGF. Although both of the immobilized samples show dose-dependency when seeded with high number of fibroblast cells, CNBr-agarose-EGF showed a significantly high activity at 100 ng/mL and 72 h incubation, compared to glyoxyl-agarose-EGF.

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