Biomaterials for direct cardiac repair-A rapid scoping review 2012-2022.

A plethora of biomaterials for heart repair are being tested worldwide for potential clinical application. These therapeutics aim to enhance the quality of life of patients with heart disease using various methods to improve cardiac function. Despite the myriad of therapeutics tested, only a minority of these studied biomaterials have entered clinical trials. This rapid scoping review aims to analyze literature available from 2012 to 2022 with a focus on clinical trials using biomaterials for direct cardiac repair, i.e., where the intended function of the biomaterial is to enhance the repair of the endocardium, myocardium, epicardium or pericardium. This review included neither biomaterials related to stents and valve repair nor biomaterials serving as vehicles for the delivery of drugs. Surprisingly, the literature search revealed that only 8 different biomaterials mentioned in 23 different studies out of 7038 documents (journal articles, conference abstracts or clinical trial entries) have been tested in clinical trials since 2012. All of these, intended to treat various forms of ischaemic heart disease (heart failure, myocardial infarction), were of natural origin and most used direct injections as their delivery method. This review thus reveals notable gaps between groups of biomaterials tested pre-clinically and clinically. STATEMENT OF SIGNIFICANCE: Rapid scoping review of clinical application of biomaterials for cardiac repair. 7038 documents screened; 23 studies mention 8 different biomaterials only. Biomaterials for repair of endocardium, myocardium, epicardium or pericardium. Only 8 different biomaterials entered clinical trials in the past 10 years. All of the clinically translated biomaterials were of natural origin.

An Injectable, Shape-Retaining Collagen Hydrogel Cross-linked Using Thiol-Maleimide Click Chemistry for Sealing Corneal Perforations.

Injectable hydrogels show great promise in developing novel regenerative medicine solutions and present advantages for minimally invasive applications. Hydrogels based on extracellular matrix components, such as collagen, have the benefits of cell adhesiveness, biocompatibility, and degradability by enzymes. However, to date, reported collagen hydrogels possess severe shortcomings, such as nonbiocompatible cross-linking chemistry, significant swelling, limited range of mechanical properties, or gelation kinetics unsuitable for in vivo injection. To solve these issues, we report the design and characterization of an injectable collagen hydrogel based on covalently modified acetyl thiol collagen cross-linked using thiol-maleimide click chemistry. The hydrogel is injectable for up to 72 h after preparation, shows no noticeable swelling, is transparent, can be molded in situ, and retains its shape in solution for at least one year. Notably, the hydrogel mechanical properties can be fine-tuned by simply adjusting the reactant stoichiometries, which to date was only reported for synthetic polymer hydrogels. The biocompatibility of the hydrogel is demonstrated in vitro using human corneal epithelial cells, which maintain viability and proliferation on the hydrogels for at least seven days. Furthermore, the developed hydrogel showed an adhesion strength on soft tissues similar to fibrin glue. Additionally, the developed hydrogel can be used as a sealant for repairing corneal perforations and can potentially alleviate the off-label use of cyanoacrylate tissue adhesive for repairing corneal perforations. Taken together, these characteristics show the potential of the thiol collagen hydrogel for future use as a prefabricated implant, injectable filler, or as sealant for corneal repair and regeneration.

Checklists to detect potential predatory biomedical journals: a systematic review.

BACKGROUND: The increase in the number of predatory journals puts scholarly communication at risk. In order to guard against publication in predatory journals, authors may use checklists to help detect predatory journals. We believe there are a large number of such checklists yet it is uncertain whether these checklists contain similar content. We conducted a systematic review to identify checklists that help to detect potential predatory journals and examined and compared their content and measurement properties. METHODS: We searched MEDLINE, Embase, PsycINFO, ERIC, Web of Science and Library, and Information Science & Technology Abstracts (January 2012 to November 2018); university library websites (January 2019); and YouTube (January 2019). We identified sources with original checklists used to detect potential predatory journals published in English, French or Portuguese. Checklists were defined as having instructions in point form, bullet form, tabular format or listed items. We excluded checklists or guidance on recognizing "legitimate" or "trustworthy" journals. To assess risk of bias, we adapted five questions from A Checklist for Checklists tool a priori as no formal assessment tool exists for the type of review conducted. RESULTS: Of 1528 records screened, 93 met our inclusion criteria. The majority of included checklists to identify predatory journals were in English (n = 90, 97%), could be completed in fewer than five minutes (n = 68, 73%), included a mean of 11 items (range = 3 to 64) which were not weighted (n = 91, 98%), did not include qualitative guidance (n = 78, 84%), or quantitative guidance (n = 91, 98%), were not evidence-based (n = 90, 97%) and covered a mean of four of six thematic categories. Only three met our criteria for being evidence-based, i.e. scored three or more "yes" answers (low risk of bias) on the risk of bias tool. CONCLUSION: There is a plethora of published checklists that may overwhelm authors looking to efficiently guard against publishing in predatory journals. The continued development of such checklists may be confusing and of limited benefit. The similarity in checklists could lead to the creation of one evidence-based tool serving authors from all disciplines.

Delivering More of an Injectable Human Recombinant Collagen III Hydrogel Does Not Improve Its Therapeutic Efficacy for Treating Myocardial Infarction.

Injectable hydrogels are a promising method to enhance repair in the heart after myocardial infarction (MI). However, few studies have compared different strategies for the application of biomaterial treatments. In this study, we use a clinically relevant mouse MI model to assess the therapeutic efficacy of different treatment protocols for intramyocardial injection of a recombinant human collagen III (rHCIII) thermoresponsive hydrogel. Comparing a single hydrogel injection at an early time point (3 h) versus injections at multiple time points (3 h, 1 week, and 2 weeks) post-MI revealed that the single injection group led to superior cardiac function, reduced scar size and inflammation, and increased vascularization. Omitting the 3 h time point and delivering the hydrogel at 1 and 2 weeks post-MI led to poorer cardiac function. The positive effects of the single time point injection (3 h) on scar size and vascular density were lost when the hydrogel's collagen concentration was increased from 1% to 2%, and it did not confer any additional functional improvement. This study shows that early treatment with a rHCIII hydrogel can improve cardiac function post-MI but that injecting more rHCIII (by increased concentration or more over time) can reduce its efficacy, thus highlighting the importance of investigating optimal treatment strategies of biomaterial therapy for MI.

Injectable Shape-Holding Collagen Hydrogel for Cell Encapsulation and Delivery Cross-linked Using Thiol-Michael Addition Click Reaction.

Injectable hydrogels based on extracellular matrix-derived polymers show much promise in the field of tissue engineering and regenerative medicine. However, the hydrogels reported to date have at least one characteristic that limits their potential for clinical use, such as excessive swelling, complicated and potentially toxic cross-linking process, or lack of shear thinning and self-healing properties. We hypothesized that a collagen hydrogel cross-linked using thiol-Michael addition click reaction would be able to overcome these limitations. To this end, collagen was modified to introduce thiol groups, and hydrogels were prepared by cross-linking with 8-arm polyethylene glycol-maleimide. Rheological measurements on the hydrogels revealed excellent shear-thinning and self-healing properties. Additionally, only minimal swelling (6%) was observed over a period of 1 month in an aqueous buffer solution. Finally, tests using mesenchymal stromal cells and endothelial cells showed that the hydrogels are cell-compatible and suitable for cell encapsulation and delivery. Thus, the reported thiolated-collagen hydrogel cross-linked using thiol-Michael addition click reaction overcomes most of the challenges in the injectable hydrogel design and is an excellent candidate for cell delivery in regenerative medicine and tissue engineering applications. The hydrogel reported here is the first example of a self-healing hydrogel containing covalent cross-links.

Collagen-Based Photoactive Agent for Tissue Bonding.

Using a combination of methacrylated collagen and the photosensitizer rose Bengal, a new light-activated biomimetic material for tissue sutureless bonding was developed. This formulation was cross-linked using green light. In vivo tests in mice demonstrate the suitability of the material for sutureless wound closure.