The co-deposition coating of collagen IV and laminin on hyaluronic acid pattern for better biocompatibility on cardiovascular biomaterials

Extracellular Matrix Interactome in Modulating Vascular Homeostasis and Remodeling

The ECM (extracellular matrix) is a major component of the vascular microenvironment that modulates vascular homeostasis. ECM proteins include collagens, elastin, noncollagen glycoproteins, and proteoglycans/glycosaminoglycans. ECM proteins form complex matrix structures, such as the basal lamina and collagen and elastin fibers, through direct interactions or lysyl oxidase-mediated cross-linking. Moreover, ECM proteins directly interact with cell surface receptors or extracellular secreted molecules, exerting matricellular and matricrine modulation, respectively. In addition, extracellular proteases degrade or cleave matrix proteins, thereby contributing to ECM turnover. These interactions constitute the ECM interactome network, which is essential for maintaining vascular homeostasis and preventing pathological vascular remodeling. The current review mainly focuses on endogenous matrix proteins in blood vessels and discusses the interaction of these matrix proteins with other ECM proteins, cell surface receptors, cytokines, complement and coagulation factors, and their potential roles in maintaining vascular homeostasis and preventing pathological remodeling.

Advances in Enhancing Hemocompatibility of Hemodialysis Hollow-Fiber Membranes

Hemodialysis, the most common modality of renal replacement therapy, is critically required to remove uremic toxins from the blood of patients with end-stage kidney disease. However, the chronic inflammation, oxidative stress as well as thrombosis induced by the long-term contact of hemoincompatible hollow-fiber membranes (HFMs) contribute to the increase in cardiovascular diseases and mortality in this patient population. This review first retrospectively analyzes the current clinical and laboratory research progress in improving the hemocompatibility of HFMs. Details on different HFMs currently in clinical use and their design are described. Subsequently, we elaborate on the adverse interactions between blood and HFMs, involving protein adsorption, platelet adhesion and activation, and the activation of immune and coagulation systems, and the focus is on how to improve the hemocompatibility of HFMs in these aspects. Finally, challenges and future perspectives for improving the hemocompatibility of HFMs are also discussed to promote the development and clinical application of new hemocompatible HFMs.

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Extracellular Matrix Coatings on Cardiovascular Materials—A Review

Vascular transplantation is an effective and common treatment for cardiovascular disease (CVD). However, the low biocompatibility of implants is a major problem that hinders its clinical application. Surface modification of implants with extracellular matrix (ECM) coatings is an effective approach to improve the biocompatibility of cardiovascular materials. The complete ECM seems to have better biocompatibility, which may give cardiovascular biomaterials a more functional surface. The use of one or several ECM proteins to construct a surface allows customization of coating composition and structure, possibly resulting in some unique functions. ECM is a complex three-dimensional structure composed of a variety of functional biological macromolecules, and changes in the composition will directly affect the function of the coating. Therefore, understanding the chemical composition of the ECM and its interaction with cells is beneficial to provide new approaches for coating surface modification. This article reviews novel ECM coatings, including coatings composed of intact ECM and biomimetic coatings tailored from several ECM proteins, and introduces new advances in coating fabrication. These ECM coatings are effective in improving the biocompatibility of vascular grafts.

The role of extracellular matrix on unfavorable maternal–fetal interface: focusing on the function of collagen in human fertility

Extracellular matrix (ECM) is characterized as widespread, abundant, and pluripotent. Among ECM members, collagen is widely accepted as one of the most prominent components for its essential structural property that can provide a scaffold for other components of ECM and the rich biological functions, which has been extensively used in tissue engineering. Emerging evidence has shown that the balance of ECM degradation and remodeling is vital to regulations of maternal–fetal interface including menstrual cycling, decidualization, embryo implantation and pregnancy maintenance. Moreover, disorders in these events may eventually lead to failure of pregnancy. Although the improvement of assisted conception and embryo culture technologies bring hope to many infertile couples, some unfavorable outcomes, such as recurrent implantation failure (RIF), recurrent pregnancy loss (RPL) or recurrent miscarriage (RM), keep troubling the clinicians and patients. Recently, in vitro three-dimensional (3D) model mimicking the microenvironment of the maternal–fetal interface is developed to investigate the physiological and pathological conditions of conception and pregnancy. The progress of this technology is based on clarifying the role of ECM in the endometrium and the interaction between endometrium and conceptus. Focusing on collagen, the present review summarized the degradation and regulation of ECM and its role in normal menstruation, endometrium receptivity and unsatisfying events occurring in infertility treatments, as well as the application in therapeutic approaches to improve pregnancy outcomes. More investigations about ECM focusing on the maternal–fetal interface interaction with mesenchymal stem cells or local immunoregulation may inspire new thoughts and advancements in the clinical application of infertility treatments.

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Endothelialization strategy of implant materials surface: The newest research in recent 5 years

In recent years, more and more metal or non-metal materials have been used in the treatment of cardiovascular diseases, but the vascular complications after transplantation are still the main factors restricting the clinical application of most grafts, such as acute thrombosis and graft restenosis. Implant materials have been extensively designed and surface optimized by researchers, but it is still too difficult to avoid complications. Natural vascular endodermis has excellent function, anti-coagulant and anti-intimal hyperplasia, and it is also the key to maintaining the homeostasis of normal vascular microenvironment. Therefore, how to promote the adhesion of endothelial cells (ECs) on the surface of cardiovascular materials to achieve endothelialization of the surface is the key to overcoming the complications after implant materialization. At present, the surface endothelialization design of materials based on materials surface science, bioactive molecules, and biological function intervention and feedback has attracted much attention. In this review, we summarize the related research on the surface modification of materials by endothelialization in recent years, and analyze the advantages and challenges of current endothelialization design ideas, explain the relationship between materials, cells, and vascular remodeling in order to find a more ideal endothelialization surface modification strategy for future researchers to meet the requirements of clinical biocompatibility of cardiovascular materials.

Hyaluronic acid-functionalized poly-lactic acid (PLA) microfibers regulate vascular endothelial cell proliferation and phenotypic shape expression

This work was designed to evaluate the efficacy of hyaluronic acid (HA) functionalized tubular poly-lactic acid (PLA) microfibers in directing the luminal pre-endothelialization of vascular endothelial cells (ECs). Tubular HA/PLA microfibers with hierarchical architecture were prepared by electrospinning and chemical cross-linking process. A layer of HA microfibrous film coating was fixed on the inner wall surface of the tubular HA/PLA microfibers, resulting in higher anisotropy wettability and relatively lower surface energy and roughness. We confirmed that HA coating on PLA microfibers surface have reduced hemolytic activity and coagulation degree. Mouse vascular ECs exhibited surface-dependent differences in cell elongation and proliferation (HA/PLA > PLA). Compared with PLA microfibers, the gene expression levels of platelet EC adhesion molecule-1 (PECAM-1/CD31) and vascular endothelial growth factor (VEGF) in ECs of HA/PLA microfibers surface were up-regulated. Immunostaining analysis revealed that the surface of HA/PLA nanofibers supported the expression of mature vascular EC phenotype CD31 protein. In vitro co-culture analysis showed that the luminal pre-endothelialization induced vascular smooth muscle cells (SMCs) to maintain their phenotypic shape and establish natural behavior patterns in the hierarchical tubular scaffold. These studies indicate that the biophysical cues of scaffolds are potent regulators of vascular EC endothelialization.

HA-coated collagen nanofibers for urethral regeneration via in situ polarization of M2 macrophages

In situ tissue engineering utilizes the regenerative potential of the human body to control cell function for tissue regeneration and has shown considerable prospect in urology. However, many problems are still to be understood, especially the interactions between scaffolds and host macrophages at the wound site and how these interactions direct tissue integration and regeneration. This study was designed to evaluate the efficacy of hyaluronic acid (HA) functionalized collagen nanofibers in modulating the pro-healing phenotype expression of macrophages for urethral regeneration. Tubular HA-collagen nanofibers with HA-coating were prepared by coaxial electrospinning. The formation of a thin HA-coating atop each collagen nanofiber endowed its nanofibrous mats with higher anisotropic wettability and mechanical softness. The macrophages growing on the surface of HA-collagen nanofibers showed an elongated shape, while collagen nanofibers' surface exhibited a pancake shape. Immunofluorescence and ELISA analysis showed that elongation could promote the expression of M2 phenotype marker and reduce the secretion of inflammatory cytokines. In vivo experiments showed that tubular HA-collagen nanofibers significantly facilitate male puppy urethral regeneration after injury. In the regenerated urethra bridged by tubular HA-collagen nanofibers, anti-inflammatory M2 macrophages are recruited to the surface of the scaffold, which can promote angiogenesis and endogenous urothelial progenitor cell proliferation.

A tailored extracellular matrix (ECM) - Mimetic coating for cardiovascular stents by stepwise assembly of hyaluronic acid and recombinant human type III collagen

Collagen, a central component of the extracellular matrix (ECM), has been widely applied in tissue engineering, among others, for wound healing or bone and nerve regeneration. However, the inherent thrombogenic properties of collagen hinder the application in blood-contacting devices. Herein, a brand-new recombinant human type III collagen (hCOLIII) was explored that does not present binding sites for platelets while retaining the affinity for endothelial cells. The hCOLIII together with hyaluronic acid (HA) were deposited on the substrates via layer-by-layer assembly to form an ECM-mimetic multilayer coating. In vitro platelet adhesion and ex vivo blood circulation tests demonstrated prominent thromboprotective properties for the hCOLIII-based ECM-mimetic coating. In addition, the coating effectively guided the vascular cell fate by supporting the proliferation of endothelial cells and inhibiting the proliferation of smooth muscle cells by differentiating them to a more contractile phenotype. A polylactic acid (PLA) stent coated with hCOLIII-based ECM-mimetic coating was implanted in the abdominal aorta of rabbits to investigate the healing of the neointima. The enhanced endothelialization, suppressed inflammatory response, inhibition of excessive neointimal hyperplasia, and the superior thromboprotection strongly indicated the prospect of the hCOLIII-based ECM-mimetic coating as a tailored blood-contacting material for cardiovascular stents.