An Injectable Dual-Function Hydrogel Protects Against Myocardial Ischemia/Reperfusion Injury by Modulating ROS/NO Disequilibrium

Hydrogel adhesives for tissue recovery

Hydrogel adhesives (HAs) are promising and rewarding tools for improving tissue therapy management. Such HAs had excellent properties and potential applications in biological tissues, such as suture replacement, long-term administration, and hemostatic sealing. In this review, the common designs and the latest progress of HAs based on various methodologies are systematically concluded. Thereafter, how to deal with interfacial water to form a robust wet adhesion and how to balance the adhesion and non-adhesion are underlined. This review also provides a brief description of gelation strategies and raw materials. Finally, the potentials of wound healing, hemostatic sealing, controlled drug delivery, and the current applications in dermal, dental, ocular, cardiac, stomach, and bone tissues are discussed. The comprehensive insight in this review will inspire more novel and practical HAs in the future.

Sprayable Reactive Oxygen Species-Responsive Hydrogel Coatings Restore Endothelial Barrier Integrity for Functional Vascular Healing

Drug-coated balloons are advancing in coronary interventional therapy for stenosis but often cause traumatic vascular injury, leading to late-stage restenosis. A critical pathological event in this process is the early disruption of the endothelial barrier integrity, which triggers inflammation and hyperplasia. However, effective therapeutic strategies to promptly restore endothelial integrity are lacking. Here, we identify the elimination of excess reactive oxygen species (ROS) as a key mechanism for reinforcing intercellular tight junctions (TJs) and restoring the endothelial barrier function. We thus propose a sprayable, ROS-responsive hydrogel coating, OA@G-NO/B-EC, for vascular balloons designed to mitigate late-stage restenosis. This hydrogel, precisely fabricated via ultrasonic spraying, comprises a reversible phenylboronic ester-bearing caffeate prodrug (B-EC) and a macromolecular nitric oxide (NO) donor (G-NO), both dynamically self-cross-linked with dopamine-modified oxidized dextran (OA) through Schiff base chemistry. The dual dynamic covalent linkages enable the hydrogel to gradually disintegrate in response to ROS accumulation at lesion sites, providing controlled, on-demand therapeutic action. Sustained release of herbal antioxidant caffeates effectively scavenges ROS, rescuing TJ integrity and attenuating inflammation. This favorable microenvironment further enhances both endogenous NO production and exogenous NO delivery, facilitating endothelial proliferation and migration. Moreover, this hydrogel's robust adhesion to the arterial wall ensures sufficient drug retention and delivery. In vitro and in vivo results, supported by RNA sequencing analysis, strongly demonstrate the hydrogel's enhanced capacity for vascular healing and restenosis prevention. This system holds broad potential for surface engineering across diverse biomedical materials and devices, advancing localized drug delivery.

PCL-fibrin-alginate hydrogel based cell co-culture system for improving angiogenesis and immune modulation in limb ischemia

Stem cell therapy has demonstrated promise in regenerative medicine due to their ability to differentiate into various cell types and secrete growth factors. However, challenges such as poor survival rate of transplanted cells under ischemic and immune conditions limit its effectiveness. To address these issues, we developed a polycaprolactone (PCL)-fibrin-alginate matrix hydrogel, which combines adipose-derived stem cells and human umbilical vein endothelial cells with a PCL fiber, encapsulated within fibrin and alginate hydrogel to enhance cell survival, proliferation, and immune modulation. This structure offers protection to the encapsulated cells, supports angiogenesis, and modulates the immune response, significantly improving therapeutic outcomes in a mouse model of hindlimb ischemia. Our in vitro and in vivo results demonstrate the scaffold's ability to support cell viability, promote angiogenesis, and modulate inflammatory responses, indicating its potential as a promising platform for ischemic tissue repair and regenerative medicine. This innovative approach to cell-based therapy highlights the importance of scaffold design in enhancing the therapeutic efficacy of stem cell treatments for ischemic diseases.

Myeloid SHP2 attenuates myocardial ischemia‑reperfusion injury via regulation of BRD4/SYK/STING/NOX4/NLRP3 signaling

The objective of the present study was to investigate the impact of myeloid Src homology region 2‑containing protein tyrosine phosphatase 2 (SHP2) on myocardial ischemia reperfusion (MI/R) injury and the underlying mechanism. Bioinformatics was used to analyze genes specifically associated with MI/R. In addition, myeloid‑specific SHP2 knockout mice and wild‑type mice were subjected to MI/R or sham surgery. Echocardiography and Masson's staining were used to observe the myocardial function and infarct area of the mice. In addition, double immunofluorescence staining was used to detect the relative fluorescence intensity of SHP2 and bromodomain‑containing protein 4 (BRD4) in bone marrow‑derived macrophages (BMMs) from the mice. Western blot analysis was conducted to determine the expression levels of SHP2, BRD4, spleen tyrosine kinase (SYK), stimulator of interferon genes (STING), NADPH oxidase 4 (NOX4), NLR family pyrin domain containing 3 (NLRP3), IL‑1β and gasdermin D (GSDMD) in BMMs and mouse myocardial cells co‑cultured with the BMMs. In addition, flow cytometry was employed to assess myocardial cell apoptosis. Bioinformatics analysis revealed the downregulated expression of SHP2 and upregulated expression of BRD4 and SYK in mice with MI/R. The deletion of myeloid SHP2 aggravated MI/R injury, impaired cardiac function and increased the infarct area in mice. In addition, myeloid SHP2 deletion in BMMs promoted the expression of BRD4, SYK, STING, NOX4 and NLRP3 in BMMs, and the expression of IL‑1β and GSDMD in mouse myocardial cells co‑cultured with the BMMs. In addition, the deletion of myeloid SHP2 promoted cardiomyocyte apoptosis. These results indicate that myeloid SHP2 inhibits MI/R injury by regulating BRD4/SYK/STING/NOX4/NLRP3 signaling in BMMs.

Conductive bioadhesive hydrogel with controlled astragaloside IV release for ferroptosis-mediated cardiac repair

Myocardial infarction (MI) poses significant therapeutic challenges due to the heart's limited regenerative capacity, often resulting in fibrosis, impaired electrical conduction, and adverse ventricular remodeling. To overcome these challenges, we engineered a conductive and bioadhesive hydrogel capable of controlled, sustained release of Astragaloside IV (AST), targeting ferroptosis-associated pathways to promote cardiac repair. The hydrogel was synthesized through dynamic Schiff-base crosslinking between dopamine-functionalized gelatin (GelDA) and aldehyde-modified Pluronic F127 (F127-CHO), with polydopamine-polypyrrole (PDA-PPy) nanoparticles incorporated to enhance electrical conductivity, mechanical stability, and tissue adhesion via synergistic catechol chemistry. Thermosensitive F127 micelles within the hydrogel efficiently encapsulated and delivered AST to the infarction myocardium, overcoming the bioavailability limitations of hydrophobic therapeutics. In vitro studies confirmed that AST-loaded hydrogels effectively suppressed hypoxia-induced ferroptosis in cardiomyocytes by activating the Nrf2/HO-1 pathway, substantially reducing lipid peroxidation, attenuating inflammation, and enhancing cell viability. In vivo evaluations in a rat MI model demonstrated robust myocardial adhesion, restoration of synchronized electrical conduction, reduced fibrosis, and preservation of mitochondrial integrity. Histological assessments further revealed enhanced cardiomyocyte organization, improved intercellular connectivity, and increased neovascularization, collectively contributing to functional ventricular recovery. These results underscore the therapeutic efficacy and mechanistic innovation of this multifunctional hydrogel, presenting substantial translational potential for controlled, ferroptosis-targeted cardiac repair.

Injectable Hydrogel for Cardiac Repair via Dual Inhibition of Ferroptosis and Oxidative Stress

Ferroptosis plays a significant role in ischemic heart disease by exacerbating myocardial injury through oxidative stress, iron metabolism disorder, and inflammation. Herein, we develop an injectable hydrogel (HSD/DFO@GMs) with antiferroptosis and antioxidant properties for cardiac repair. The hydrogel is composed of dopamine-grafted oxidized hyaluronic acid, adipic acid dihydrazide grafted hyaluronic acid, and deferoxamine loaded gelatin microsphere, connected via a dynamic Schiff base bond. This hydrogel exhibits a favorable injectability and stable mechanical properties. It effectively chelates Fe2+ and scavenges the reactive oxygen species (ROS), creating a conducive microenvironment for cardiac repair. The dynamic Schiff base bond and gelatin matrix respond to the weakly acidic and MMP-2-rich microenvironment postinjury, enabling on-demand release of DFO in the injured myocardium. In vitro experiments indicate that the hydrogel significantly inhibits the ferroptosis and oxidative stress damage in H9C2 cardiomyocytes under a hypoxia/reoxygenation microenvironment. In an in vivo ischemia-reperfusion model, the HSD/DFO@GMs hydrogel reduces oxidative stress, modulates intracellular labile iron pool levels, and promotes revascularization, ultimately improving cardiac function. Overall, the HSD/DFO@GMs hydrogel provides a new strategy to improve cardiac repair by inhibiting ferroptosis and mitigating oxidative stress damage.

Immune in myocardial ischemia/reperfusion injury: potential mechanisms and therapeutic strategies

Myocardial infarction (MI), which is characterized by high morbidity and mortality, is a serious threat to human life and health, and timely reperfusion therapy to save ischemic myocardium is currently the most effective intervention. Although reperfusion therapy effectively restores coronary blood flow and maximally limits the infarct size, it triggers additional cell death and tissue damage, which is known as myocardial ischemia/reperfusion injury (MIRI). Multiple immune cells are present in the reperfusion area, executing specific functions and engaging in crosstalk during diverse stages, constituting a complex immune microenvironment involved in tissue repair and regeneration after MIRI. Immunotherapy brings new hope for treating ischemic heart disease by modulating the immune microenvironment. In this paper, we explore the regulatory roles of various immune cells during MIRI and the close relationship between different cell deaths and the immune microenvironment. In addition, we present the current status of research on targeting the immune system to intervene in MIRI, with the expectation of providing a basis for achieving clinical translation.

Multifunctional Double-Loaded Oral Nanoplatform for Computed Tomography Imaging-Guided and Integrated Treatment of Inflammatory Bowel Disease

Excessive reactive oxygen species, disruption of the epithelial barrier, immune dysregulation, and gut microbiota imbalance are key factors driving the onset of inflammatory bowel disease (IBD) and complicating its treatment. Prompt diagnosis of diseases and precise delivery of therapeutic agents to inflamed intestinal sites offer promising targeted strategies for effectively treating IBD. Here, a barium sulfate-based nanoplatform (BaSO4@PDA@CeO2/DSP, BPCD) for synergistic delivery of nanozymes and drugs was developed. With enhanced colonic retention after oral drug delivery, this nanoplatform enables precise and effective targeting of inflammatory sites and CT imaging guidance to address multiple factors contributing to IBD. A comprehensive therapeutic effect was achieved through the synergistic action of cerium oxide with the optimized Ce3+/Ce4+ ratio and sustained release of dexamethasone sodium phosphate. Benefiting from superior gastrointestinal stability, the nanoplatform is highly effective in treating IBD by alleviating oxidative stress, modulating macrophage polarization balance, gut flora composition, and repairing the epithelial barrier. BPCD inhibits the development of IBD through multiple mechanisms and has superior biocompatibility, emerging as a practical alternative to traditional IBD therapies.

Microenvironment-Regulated Hydrogels Prepared with a Brand-New Small Molecule Cross-Linker for Stepwise Treatment of Myocardial Infarction

Despite the development of many injectable hydrogels intended for the repair of myocardial infarction (MI), their effectiveness is often compromised because they target merely one or two phases of MI's pathological progression. Here, a multifunctional hydrogel delivery platform is prepared with a brand-new small molecule cross-linker for stepwise treatment of MI. The synthesis and reporting of a novel small-molecule phenylboronic acid cross-linker ((N(BA)3)) with a precise molecular structure is conducted for the first time, and it is successfully utilized with polyvinyl alcohol (PVA) dopamine to prepare a hydrogel with infarct microenvironmental responsiveness and anti-oxidant. Further, considering the multistage of MI repair, hydrogel contains both hyperoside bioactive nanoparticles (EGCG@Hyp&Arg NPs) and PLGA microspheres loaded with galunisertib (PLGA@Gal Ms). The EGCG@Hyp&Arg NPs are rapidly released and demonstrate anti-inflammatory and pro-angiogenesis effects, while in the long term, Gal is released from the PLGA@Gal Ms to inhibit myocardial fibrosis and improve cardiac function. Results from both in vitro and in vivo studies reveal that the hydrogel is engineered with programmed capabilities for anti-oxidation, reducing inflammation, promoting new blood vessel formation, and inhibiting fibrosis, thereby significantly enhancing heart function post-MI. Overall, this multifunctional hydrogel delivery platform has great potential for application as a therapeutic strategy for MI.

Innovative approaches to boost mesenchymal stem cells efficacy in myocardial infarction therapy

Stem cell-based therapy has emerged as a promising approach for heart repair, potentially regenerating damaged heart tissue and improving outcomes for patients with heart disease. However, the efficacy of stem cell-based therapies remains limited by several challenges, including poor cell survival, low retention rates, poor integration, and limited functional outcomes. This article reviews current enhancement strategies to optimize mesenchymal stem cell therapy for cardiac repair. Key approaches include optimizing cell delivery methods, enhancing cell engraftment, promoting cell functions through genetic and molecular modifications, enhancing the paracrine effects of stem cells, and leveraging biomaterials and tissue engineering techniques. By focusing on these enhancement techniques, the paper highlights innovative approaches that can potentially transform stem cell therapy into a more viable and effective treatment option for cardiac repair. The ongoing research and technological advancements continue to push the boundaries, hoping to make stem cell therapy a mainstream treatment for heart disease.

Diselenide Nanogels Modulate Mitochondrial Function and Mitigate Oxidative Stress in Cardiomyocytes for Enhanced Cardiac Repair

Mitochondrial dysfunction and oxidative stress are pivotal factors contributing to the loss of cardiac function following heart injury, yet these aspects are frequently underappreciated in the medication design paradigm. Here we have developed diselenide-cross-linked zwitterionic nanogels to restore mitochondrial homeostasis and boost energy supply for damaged heart repair. These nanogels exhibit an enhanced circulation time within the bloodstream post systemic administration and have been observed to concentrate at the site of the damaged myocardium in both myocardial infarct (MI) rat model and cardiotoxic mouse model. Our mechanistic investigations have revealed that these nanogels have the capacity to mitigate the oxidative microenvironment, thereby preserving the mitochondrial function of cardiomyocytes. Moreover, the degradation products of these nanogels have been shown to upregulate intracellular ATP synthesis, which in turn increases cardiac contractility and promotes the recovery of cardiac function. The innovative nanogel system presented herein holds significant potential for clinical translation, offering a therapeutic strategy for the restoration of cardiac function and a fresh perspective on maintaining energy metabolism homeostasis in the treatment of heart injury.

Design and advances in antioxidant hydrogels for ROS-induced oxidative disease

Reactive oxygen species (ROS) play a crucial role in human physiological processes, but oxidative stress caused by excessive ROS may lead to a variety of acute and chronic diseases. Despite the development of various strategies and biomaterials, an efficiently and broadly applied method for treatment of ROS-induced oxidative disease remains a bottleneck. Aiming to improve the local oxidative stress environment, numerous bioactive hydrogels with antioxidant properties have emerged and are proven to quickly and continuously eliminate excessive ROS. To deeply understand the design principles and applications of antioxidant hydrogels is highly beneficial for designing antioxidant hydrogels for treatment of oxidative disease. This review provides a detailed summary of recent advances in design and applications of antioxidant hydrogels for various ROS-induced oxidative diseases. In this review, the kinds of antioxidant components in antioxidant hydrogels are outlined in detail. Additionally, the crosslinking methods and the biomedical applications of antioxidant hydrogels are widely summarized and discussed, especially focusing on their usage in different types of diseases and the attention given to the treatment of diseases such as skin wounds, myocardial infarction, and osteoarthritis. Finally, the future development direction of antioxidant hydrogel is further proposed. STATEMENT OF SIGNIFICANCE: Oxidative stress is a pivotal biochemical process that plays a critical role in cellular homeostasis. Excessive cellular oxidative stress triggers an inflammatory response, which is implicated in a spectrum of associated diseases. Given the critical need for managing oxidative stress, antioxidant therapies have become a vital focus in medical research. Hydrogels have garnered substantial interest among biomaterial scientists due to their hydrophilic nature and biocompatibility. The review delves into the realm of antioxidant hydrogels, encompassing the classification of antioxidant components, the synthesis and fabrication of hydrogels, and a comprehensive overview of the biological applications and challenges of these antioxidant hydrogels. Aiming to provide new perspectives for researchers in developing cutting-edge therapeutic approaches that leverage antioxidant hydrogels.

Extracellular matrix gene set and microRNA network in intestinal ischemia-reperfusion injury: Insights from RNA sequencing for diagnosis and therapy

Intestinal ischemia-reperfusion injury (IIRI) is a complex and severe pathophysiological process characterized by oxidative stress, inflammation, and apoptosis. In recent years, the critical roles of extracellular matrix (ECM) genes and microRNAs (miRNAs) in IIRI have garnered widespread attention. This review aims to systematically summarize the diagnostic and therapeutic potential of ECM gene sets and miRNA regulatory networks in IIRI. First, we review the molecular mechanisms of IIRI, focusing on the dual role of the ECM in tissue injury and repair processes. The expression changes and functions of ECM components such as collagen, elastin, and matrix metalloproteinases during IIRI progression are deeply analyzed. Second, we systematically summarize the regulatory roles of miRNAs in IIRI, particularly the mechanisms and functions of miRNAs such as miR-125b and miR-200a in regulating inflammation, apoptosis, and ECM remodeling. Additionally, this review discusses potential diagnostic biomarkers and treatment strategies based on ECM genes and miRNAs. We extensively evaluate the prospects of miRNA-targeted therapy and ECM component modulation in preventing and treating IIRI, emphasizing the clinical translational potential of these emerging therapies. In conclusion, the diagnostic and therapeutic potential of ECM gene sets and miRNA regulatory networks in IIRI provides new directions for further research, necessitating additional clinical and basic studies to validate and expand these findings for improving clinical outcomes in IIRI patients.

Injectable pH Responsive Conductive Hydrogel for Intelligent Delivery of Metformin and Exosomes to Enhance Cardiac Repair after Myocardial Ischemia-Reperfusion Injury

Myocardial ischemia-reperfusion injury (MIRI) is a leading cause of complications and high mortality associated with acute myocardial infarction. Injectable hydrogel emerges as a promising biomaterial for myocardial repair due to their ability to mimic the mechanical and electrophysiological properties of heart tissue. In this study, an injectable conductive hydrogel is developed that responds to the weakly acidic microenvironment of ischemic injury, enabling the intelligent release of metformin and exosomes to enhance cardiac repair following MIRI. This multifunctional hydrogel demonstrates self-healing properties, shear-thinning injectability, electrical conductivity, and an elastic modulus comparable to natural myocardium, alongside excellent biocompatibility. At the cellular level, the hydrogel system exhibits significant antioxidant, anti-apoptotic, improvement of electrophysiological characteristics, mitochondrial protection and angiogenic effects, with transcriptome sequencing revealing the effective activation of the PI3K/AKT, VEGF, and AMPK signaling pathways. In vivo studies further confirm that the hydrogel treatment reduces infarct size, cardiac fibrosis and incidence of arrhythmia, while improving ventricular ejection fraction and facilitating the restoration of cardiac function after MIRI. In conclusion, an injectable pH-responsive conductive hydrogel is presented that enables the intelligent delivery of metformin and exosomes, offering a promising and novel therapeutic approach for enhancing cardiac repair and treating MIRI.

Nanomaterials: Promising Tools for the Diagnosis and Treatment of Myocardial Infarction

Myocardial infarction (MI) is the leading cause of mortality from cardiovascular diseases. Rapid diagnosis and effective treatment are critical for improving patient prognosis. Although current diagnostic and therapeutic approaches have made significant progress, they still face challenges such as ischemia-reperfusion injury, microcirculatory disorders, adverse cardiac remodeling, and inflammatory responses. These issues highlight the urgent need for innovative solutions. Nanomaterials, with their diverse types, excellent physicochemical properties, biocompatibility, and targeting capabilities, offer promising potential in addressing these challenges. Advances in nanotechnology have increasingly drawn attention to the application of nanomaterials in both diagnosing and treating myocardial infarction. We summarize the pathophysiological mechanisms and staging of myocardial infarction. We systematically review the applications of nanomaterials in MI diagnosis, including the detection of biomarkers and imaging techniques, as well as in MI treatment, encompassing anti-inflammatory effects, antioxidant stress, inhibition of fibrosis, promotion of angiogenesis, and cardiac conduction repair. We analyze the existing challenges and provide insights into future research directions and potential solutions. Specifically, we discuss the need for rigorous safety assessments, long-term efficacy studies, and the development of robust strategies for translating laboratory findings into clinical practice. In conclusion, nanotechnology holds significant promise as a new strategy for diagnosing and treating myocardial infarction. Its potential to enhance clinical outcomes and revolutionize patient care makes it an exciting area of research with practical applications in real-world clinical settings.

Multifunctional NO supramolecular nanomedicine for thrombus risk reduction and intimal hyperplasia inhibition

Cardiovascular diseases (CVDs) are the foremost cause of mortality worldwide, with incidence and mortality rates persistently climbing despite extensive research efforts. Innovative therapeutic approaches are still needed to extend patients' lives and preserve their health. In the present study, novel supramolecular nanomedicine with both nitric oxide (NO) and antioxidant releasing ability was developed to enhance therapeutic efficacy against vascular injuries. Utilizing α-cyclodextrin (α-CD) as a host molecule, the nanomedicine aims to achieve site-specific delivery via targeting peptide rendered selective accumulation. By scavenging ROS and amplifying NO's regulatory effects, the nanomedicine readily restored vascular homeostasis, in both acute and chronic CVDs. It served as a promising solution to overcome the challenges associated with NO-based therapies and may inspire future research studies on new therapies for CVDs.

Rational Design of Genetically Engineered Mitochondrial-Targeting Nanozymes for Alleviating Myocardial Ischemic-Reperfusion Injury

The development of mitochondria-targeting nanozymes holds significant promise for treating myocardial ischemia-reperfusion (IR) injury but faces significant biological barriers. To overcome these obstacles, we herein utilized genetically engineered ferritin nanocages (i.e., imFTn) to develop mitochondria-targeting nanozymes consisting of three ferritin subunit assembly modules: an IR-injured cardiomyocyte-targeting module, a lysosome-escaping module, and a mitochondria-targeting module. Using imFTn as a nanozyme platform, we developed nanozymes capable of efficiently catalyzing the l-Arg substrate to produce NO. The imFTn-Ru exhibits NO-generating activities, reduces mitochondrial reactive oxygen species generation, inhibits mitochondrial permeability transition pore opening, and enhances mitochondrial membrane potential. Furthermore, imFTn-Ru provides synergistic effects by specifically targeting myocardial IR-injured tissues, facilitating their accumulation in mitochondria, and protecting mitochondria against myocardial IR-induced injury in both in vitro and in vivo models. This study underscores a rational approach to designing nanozymes for targeting specific subcellular organelles in the treatment of IR injury.

Innovative hydrogel-based therapies for ischemia-reperfusion injury： bridging the gap between pathophysiology and treatment

Ischemia-reperfusion injury (IRI) commonly occurs in clinical settings, particularly in medical practices such as organ transplantation, cardiopulmonary resuscitation, and recovery from acute trauma, posing substantial challenges in clinical therapies. Current systemic therapies for IRI are limited by poor drug targeting, short efficacy, and significant side effects. Owing to their exceptional biocompatibility, biodegradability, excellent mechanical properties, targeting capabilities, controlled release potential, and properties mimicking the extracellular matrix (ECM), hydrogels not only serve as superior platforms for therapeutic substance delivery and retention, but also facilitate bioenvironment cultivation and cell recruitment, demonstrating significant potential in IRI treatment. This review explores the pathological processes of IRI and discusses the roles and therapeutic outcomes of various hydrogel systems. By categorizing hydrogel systems into depots delivering therapeutic agents, scaffolds encapsulating mesenchymal stem cells (MSCs), and ECM-mimicking hydrogels, this article emphasizes the selection of polymers and therapeutic substances, and details special crosslinking mechanisms and physicochemical properties, as well as summarizes the application of hydrogel systems for IRI treatment. Furthermore, it evaluates the limitations of current hydrogel treatments and suggests directions for future clinical applications.

Peroxynitrite-Free Nitric Oxide-Embedded Nanoparticles Maintain Nitric Oxide Homeostasis for Effective Revascularization of Myocardial Infarcts

Revascularization is crucial for treating myocardial infarction (MI). Nitric oxide (NO), at an appropriate concentration, is recognized as an ideal and potent pro-angiogenic factor. However, the application of NO in the treatment of MI is limited. Improper NO supplementation is harmful to revascularization because NO is converted into harmful peroxynitrite (ONOO-) in MI tissues with high reactive oxygen species (ROS) levels. We overcome these obstacles by embedding biliverdin and NO into Prussian blue (PB) nanolattices to obtain an ONOO--free NO-embedded nanomedicine (OFEN). Unlike previous NO donors, OFEN provides NO stably and spontaneously for a longer time (>7 days), which makes it possible to maintain a stable concentration of NO, suitable for angiogenesis, through dose optimization. More importantly, based on the synergy between PB and biliverdin, OFEN converts ROS into beneficial O2 and inhibits the production of ONOO- from the source. OFEN specifically targets MI tissues and achieves sustained and stable NO delivery at the MI site. OFEN effectively promotes revascularization in the MI tissue, significantly reduces myocardial death and fibrosis, and ultimately promotes the complete recovery of cardiac function. Our strategy provides a promising approach for the treatment of myocardial and other ischemic diseases.

Drug-Loaded Mesoporous Polydopamine Nanoparticles in Chitosan Hydrogels Enable Myocardial Infarction Repair through ROS Scavenging and Inhibition of Apoptosis

In this study, we synthesized mesoporous polydopamine nanoparticles (MPDA NPs) using an emulsion-induced interface assembly strategy and loaded epigallocatechin gallate (EGCG) into MPDA NPs via electrostatic attraction to form EGCG@MPDA NPs. In the post myocardial infarction (MI) environment, these interventions specifically aimed to eliminate reactive oxygen species (ROS) and facilitate the repair of MI. We further combined them with a thermosensitive chitosan (CS) hydrogel to construct an injectable composite hydrogel (EGCG@MPDA/CS hydrogel). Utilizing in vitro experiments, the EGCG@MPDA/CS hydrogel exhibited excellent ROS-scavenging ability of H9C2 cells under the oxidative stress environment and also could inhibit their apoptosis. The EGCG@MPDA/CS hydrogel significantly promoted left ventricular ejection fraction (LVEF) in infarcted rat models post injection for 28 days compared to the PBS group (51.25 ± 1.73% vs 29.31 ± 0.78%, P < 0.05). In comparison to the PBS group, histological analysis revealed a substantial increase in left ventricular (LV) wall thickness in the EGCG@MPDA/CS hydrogel group (from 0.58 ± 0.03 to 1.39 ± 1.11 mm, P < 0.05). This work presents a novel approach to enhance MI repair by employing the EGCG@MPDA/CS hydrogel. This hydrogel effectively reduces local oxidative stress by ROS and stimulates the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway.

Nitric oxide-based multi-synergistic nanomedicine: an emerging therapeutic for anticancer

Gas therapy has emerged as a promising approach for treating cancer, with gases like NO, H2S, and CO showing positive effects. Among these, NO is considered a key gas molecule with significant potential in stopping cancer progression. However, due to its high reactivity and short half-life, delivering NO directly to tumors is crucial for enhancing cancer treatment. NO-driven nanomedicines (NONs) have been developed to effectively deliver NO donors to tumors, showing great progress in recent years. This review provides an overview of the latest advancements in NO-based cancer nanotherapeutics. It discusses the types of NO donors used in current research, the mechanisms of action behind NO therapy for cancer, and the different delivery systems for NO donors in nanotherapeutics. It also explores the potential of combining NO donors with other treatments for enhanced cancer therapy. Finally, it examines the future prospects and challenges of using NONs in clinical settings for cancer treatment.

Cu-Doping Layered Double Hydroxides Nanozyme Integrated with Nitric Oxide Donor for Enhanced Antioxidant Therapy in Retinopathy

The prevalence of retinal neovascular diseases necessitates novel treatments beyond current therapies like laser surgery or anti-VEGF treatments, which often carry significant side effects. A novel therapeutic approach is introduced using copper-containing layered double hydroxides (Cu-LDH) nanozymes integrated with nitric oxide-releasing molecules (GSHNO), forming Cu-LDH@GSHNO aimed at combating oxidative stress within the retinal vascular system. Combination of synthetic chemistry and biological testing, Cu-LDH@GSHNO are synthesized, characterized, and assessed for curative effect in HUVECs and an oxygen-induced retinopathy (OIR) mouse model. The results indicate that Cu-LDH@GSHNO demonstrates SOD-CAT cascade catalytic ability, accompanied with GSH and nitric oxide-releasing capabilities, which significantly reduces oxidative cell damage and restores vascular function, presenting a dual-function strategy that enhances treatment efficacy and safety for retinal vascular diseases. The findings encourage further development and clinical exploration of nanozyme-based therapies, promising a new horizon in therapeutic approaches for managing retinal diseases driven by oxidative stress.

Oxidative Stress and Inflammation in Myocardial Ischemia-Reperfusion Injury: Protective Effects of Plant-Derived Natural Active Compounds

Acute myocardial infarction (AMI) remains a leading cause of death among patients with cardiovascular diseases. Percutaneous coronary intervention (PCI) has been the preferred clinical treatment for AMI due to its safety and efficiency. However, research indicates that the rapid restoration of myocardial oxygen supply following PCI can lead to secondary myocardial injury, termed myocardial ischemia-reperfusion injury (MIRI), posing a grave threat to patient survival. Despite ongoing efforts, the mechanisms underlying MIRI are not yet fully elucidated. Among them, oxidative stress and inflammation stand out as critical pathophysiological mechanisms, playing significant roles in MIRI. Natural compounds have shown strong clinical therapeutic potential due to their high efficacy, availability, and low side effects. Many current studies indicate that natural compounds can mitigate MIRI by reducing oxidative stress and inflammatory responses. Therefore, this paper reviews the mechanisms of oxidative stress and inflammation during MIRI and the role of natural compounds in intervening in these processes, aiming to provide a basis and reference for future research and development of drugs for treating MIRI.

Research progress of two-pore potassium channel in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a secondary injury caused by restoring blood flow after acute myocardial infarction, which may lead to serious arrhythmia and heart damage. In recent years, the role of potassium channels in MIRI has attracted much attention, especially the members of the two-pore domain potassium (K2P) channel family. K2P channel has unique structure and function, and the formation of its heterodimer increases its functional diversity. This paper reviews the structural characteristics, types, expression and physiological functions of K2P channel in the heart. In particular, we pay attention to whether members of the subfamily such as TWIK, TREK, TASK, TALK, THIK and TRESK participate in MIRI and their related mechanisms. Future research will help to reveal the molecular mechanism of K2P channel in MIRI and provide new strategies for the treatment of cardiovascular diseases.

Advances in Functionalized Hydrogels in the Treatment of Myocardial Infarction and Drug-Delivery Strategies

Myocardial infarction (MI) is a serious cardiovascular disease with high morbidity and mortality rates, posing a significant threat to patient's health and quality of life. Following a MI, the damaged myocardial tissue is typically not fully repaired, leading to permanent impairment of myocardial function. While traditional treatments can alleviate symptoms and reduce pain, their ability to repair damaged heart muscle tissue is limited. Functionalized hydrogels, a broad category of materials with diverse functionalities, can enhance the properties of hydrogels to cater to the needs of tissue engineering, drug delivery, medical dressings, and other applications. Recently, functionalized hydrogels have emerged as a promising new therapeutic approach for the treatment of MI. Functionalized hydrogels possess outstanding biocompatibility, customizable mechanical properties, and drug-release capabilities. These properties enable them to offer scaffold support, drug release, and tissue regeneration promotion, making them a promising approach for treating MI. This paper aims to evaluate the advancements and delivery methods of functionalized hydrogels for treating MI, while also discussing their potential and the challenges they may pose for future clinical use.

Ellagic acid-enhanced biocompatibility and bioactivity in multilayer core-shell gold nanoparticles for ameliorating myocardial infarction injury

BACKGROUND

Myocardial infarction (MI) is the main contributor to most cardiovascular diseases (CVDs), and the available post-treatment clinical therapeutic options are limited. The development of nanoscale drug delivery systems carrying natural small molecules provides biotherapies that could potentially offer new treatments for reactive oxygen species (ROS)-induced damage in MI. Considering the stability and reduced toxicity of gold-phenolic core-shell nanoparticles, this study aims to develop ellagic acid-functionalized gold nanoparticles (EA-AuNPs) to overcome these limitations.

RESULTS

We have successfully synthesized EA-AuNPs with enhanced biocompatibility and bioactivity. These core-shell gold nanoparticles exhibit excellent ROS-scavenging activity and high dispersion. The results from a label-free imaging method on optically transparent zebrafish larvae models and micro-CT imaging in mice indicated that EA-AuNPs enable a favorable excretion-based metabolism without overburdening other organs. EA-AuNPs were subsequently applied in cellular oxidative stress models and MI mouse models. We found that they effectively inhibit the expression of apoptosis-related proteins and the elevation of cardiac enzyme activities, thereby ameliorating oxidative stress injuries in MI mice. Further investigations of oxylipin profiles indicated that EA-AuNPs might alleviate myocardial injury by inhibiting ROS-induced oxylipin level alterations, restoring the perturbed anti-inflammatory oxylipins.

CONCLUSIONS

These findings collectively emphasized the protective role of EA-AuNPs in myocardial injury, which contributes to the development of innovative gold-phenolic nanoparticles and further advances their potential medical applications.

Application of Pro-angiogenic Biomaterials in Myocardial Infarction

Biomaterials have potential applications in the treatment of myocardial infarction (MI). These biomaterials have the ability to mechanically support the ventricular wall and to modulate the inflammatory, metabolic, and local electrophysiological microenvironment. In addition, they can play an equally important role in promoting angiogenesis, which is the primary prerequisite for the treatment of MI. A variety of biomaterials are known to exert pro-angiogenic effects, but the pro-angiogenic mechanisms and functions of different biomaterials are complex and diverse, and have not yet been systematically described. This review will focus on the pro-angiogenesis of biomaterials and systematically describe the mechanisms and functions of different biomaterials in promoting angiogenesis in MI.

Reactive oxygen species (ROS)-responsive biomaterials for treating myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a critical issue that arises when restoring blood flow after an ischemic event in the heart. Excessive reactive oxygen species (ROS) production during this process exacerbates cellular damage and impairs cardiac function. Recent therapeutic strategies have focused on leveraging the ROS microenvironment to design targeted drug delivery systems. ROS-responsive biomaterials have emerged as promising candidates, offering enhanced therapeutic efficacy with reduced systemic adverse effects. This review examines the mechanisms of ROS overproduction during myocardial ischemia-reperfusion and summarizes significant advancements in ROS-responsive biomaterials for MIRI treatment. We discuss various chemical strategies to impart ROS sensitivity to these materials, emphasizing ROS-induced solubility switches and degradation mechanisms. Additionally, we highlight various ROS-responsive therapeutic platforms, such as nanoparticles and hydrogels, and their unique advantages in drug delivery for MIRI. Preclinical studies demonstrating the efficacy of these materials in mitigating MIRI in animal models are reviewed, alongside their mechanisms of action and potential clinical implications. We also address the challenges and future prospects of translating these state of the art biomaterial-based therapeutics into clinical practice to improve MIRI management and cardiac outcomes. This review will provide valuable insights for researchers and clinicians working on novel therapeutic strategies for MIRI intervention.

TRIM11 expression levels was downregulated and prevents ferroptosis of cardiomyocyte by Dusp6 in acute myocardial infarction

Acute myocardial infarction (AMI) is the high incidence rate and mortality of common cardiovascular disease. Herein, we explored the critical role of TRIM11 in AMI and its underlying mechanism. Serum from patients with AMI were collected from our hospital. Mice of model group received angiotensin II. Mice of model + TRIM11 group received with Ang II and TRIM11 vectors. Mice of sham group received normal saline. H9c2 cells were performed transfections using Lipofectamine 2000 (Thermo Fisher Scientific Inc, Shanghai, China), and treated with Ang II. TRIM11 mRNA expression was reduced, was negative correlation with collagen I/III mRNA expression, systolic blood pressure, diastolic blood pressure, left anteroposterior atrial diameter, right atrial diameter, or left ventricular ejection fraction in patient with AMI. TRIM11 mRNA and protein expression were also suppressed. METTL3 regulates TRIM11 methylation to reduce TRIM11 gene stability in model of AMI. TRIM11 gene ameliorated AMI in mice model. TRIM11 gene reduced reactive oxygen species production level of cardiomyocyte in-vitro model. TRIM11 gene reduced ferroptosis of cardiomyocyte in-vitro model. TRIM11 gene reduced ferroptosis by the inhibition of mitochondrial damage of cardiomyocyte in model of AMI. TRIM11 induced Dusp6 protein expression. Bioluminescence imaging showed that TRIM11 virus increased Dusp6 expression in heart tissue of mice model. The inhibition of Dusp6 reduced the effects of TRIM11 on ferroptosis of cardiomyocyte in model of AMI. In conclusion, this study demonstrates that TRIM11 improves AMI by regulating Dusp6 to inhibit ferroptosis of cardiomyocyte, and suggest a novel target for AMI.

Reactive Oxygen Species-Responsive Composite Fibers Regulate Oxidative Metabolism through Internal and External Factors to Promote the Recovery of Nerve Function

It is challenging to sufficiently regulate endogenous neuronal reactive oxygen species (ROS) production, reduce neuronal apoptosis, and reconstruct neural networks under spinal cord injury conditions. Here, hydrogel surface grafting and microsol electrospinning are used to construct a composite biomimetic scaffold with "external-endogenous" dual regulation of ROS. The outer hydrogel enhances local autophagy through responsive degradation and rapid release of rapamycin (≈80% within a week), neutralizing extracellular ROS and inhibiting endogenous ROS production, further reducing neuronal apoptosis. The inner directional fibers continuously supply brain-derived neurotrophic factors to guide axonal growth. The results of in vitro co-culturing show that the dual regulation of oxidative metabolism by the composite scaffold approximately doubles the neuronal autophagy level, reduces 60% of the apoptosis induced by oxidative stress, and increases the differentiation of neural stem cells into neuron-like cells by ≈2.5 times. The in vivo results show that the composite fibers reduce the ROS levels by ≈80% and decrease the formation of scar tissue. RNA sequencing results show that composite scaffolds upregulate autophagy-associated proteins, antioxidase genes, and axonal growth proteins. The developed composite biomimetic scaffold represents a therapeutic strategy to achieve neurofunctional recovery through programmed and accurate bidirectional regulation of the ROS cascade response.

Brown Adipose Stem Cell-Loaded Resilin Elastic Hydrogel Rebuilds Cardiac Function after Myocardial Infarction via Collagen I/III Reorganisation

Irreversible fibrosis following myocardial infarction (MI) stiffens the infarcted myocardium, which remains challenging to restore. This study aimed to investigate whether the injectable RLP12 hydrogel, derived from recombinant resilin protein, could serve as a vehicle for stem cells to enhance the function of the infarcted myocardium. The RLP12 hydrogel was prepared and injected into the myocardium of rats with MI, and brown adipose-derived mesenchymal stem cells (BADSCs) were loaded. The survival and differentiation of BADSCs in vivo were investigated using immunofluorescence one week and four weeks after treatment, respectively. The heart function, MI area, collagen deposition, and microvessel density were further assessed four weeks after treatment through echocardiography, histology, immunohistochemistry, and immunofluorescence. The RLP12 hydrogel was prepared with a shear modulus of 10-15 kPa. Four weeks after transplantation, the RLP12 hydrogel significantly improved cardiac function by increasing microvessel density and reducing infarct area size and collagen deposition in MI rats. Furthermore, the distribution ratio of collagen III to I increased in both the centre and edge areas of the MI, indicating the improved compliance of the infarct heart. Moreover, the RLP12 hydrogel also promoted the survival and differentiation of BADSCs into cardiac troponin T- and α-smooth muscle-positive cells. The RLP12 hydrogel can be utilised as an injectable vehicle of BADSCs for treating MI and regulating collagen I and III expression profiles to improve the mechanical microenvironment of the infarct site, thereby restoring heart function. The study provides novel insights into the mechanical interactions between the hydrogel and the infarct microenvironment.

Nanomedicines as Guardians of the Heart: Unleashing the Power of Antioxidants to Alleviate Myocardial Ischemic Injury

Ischemic heart disease (IHD) is increasingly recognized as a significant cardiovascular disease with a growing global incidence. Interventions targeting the oxidative microenvironment have long been pivotal in therapeutic strategies. However, many antioxidant drugs face limitations due to pharmacokinetic and delivery challenges, such as short half-life, poor stability, low bioavailability, and significant side effects. Fortunately, nanotherapies exhibit considerable potential in addressing IHD. Nanomedicines offer advantages such as passive/active targeting, prolonged circulation time, enhanced bioavailability, and diverse carrier options. This comprehensive review explores the advancements in nanomedicines for mitigating IHD through oxidative stress regulation, providing an extensive overview for researchers in the field of antioxidant nanomedicines. By inspiring further research, this study aims to accelerate the development of novel therapies for myocardial injury.

Targeted H2S-Mediated Gas Therapy with pH-Sensitive Release Property for Myocardial Ischemia-Reperfusion Injury by Platelet Membrane

Management of myocardial ischemia-reperfusion injury (MIRI) in reperfusion therapy remains a major obstacle in the field of cardiovascular disease, but current available therapies have not yet been achieved in mitigating myocardial injury due to the complex pathological mechanisms of MIRI. Exogenous delivery of hydrogen sulfide (H2S) to the injured myocardium can be an effective strategy for treating MIRI due to the multiple physiologic functions of H2S, including anti-inflammatory, anti-apoptotic, and mitochondrial protective effects. Here, to realize the precise delivery and release of H2S, we proposed the targeted H2S-mediated gas therapy with pH-sensitive release property mediated by platelet membranes (PMs). In this study, a biomimetic functional poly(lactic-co-ethanolic acid) nanoparticle (RAPA/JK-1-PLGA@PM) was fabricated by loading rapamycin (RAPA; mTOR inhibitor) and JK-1 (H2S donor) and then coated with PM. In vitro observations were conducted including pharmaceutical evaluation, H2S release behaviors, hemolysis analysis, serum stability, cellular uptake, cytotoxicity, inhibition of myocardial apoptosis, and anti-inflammation. In vivo examinations were performed including targeting ability, restoration of cardiac function, inhibition of pathological remodeling, and anti-inflammation. RAPA/JK-1-PLGA@PM was successfully prepared with good size distribution and stability. Utilizing the natural infarct-homing ability of PM, RAPA/JK-1-PLGA@PM could be effectively targeted to the damaged myocardium. RAPA/JK-1-PLGA@PM continuously released H2S triggered by inflammatory microenvironment, which could inhibit cardiomyocyte apoptosis, realize the transition of pro-inflammation, and alleviate myocardial injury demonstrated in hypoxia/reoxygenation myocardial cell in vitro. Precise delivery and release of H2S attenuated inflammatory response and cardiac damage, promoted cardiac repair, and ameliorated cardiac function proven in MIRI mouse model in vivo. This research outlined the novel nanoplatform that combined immunosuppressant agents and H2S donor with the pH-sensitive release property, offering a promising therapeutic for MIRI treatment that leveraged the synergistic effects of gas therapy.

Cardiac tissue engineering: an emerging approach to the treatment of heart failure

Heart failure is a major health problem in which the heart is unable to pump enough blood to meet the body's needs. It is a progressive disease that becomes more severe over time and can be caused by a variety of factors, including heart attack, cardiomyopathy and heart valve disease. There are various methods to cure this disease, which has many complications and risks. The advancement of knowledge and technology has proposed new methods for many diseases. One of the promising new treatments for heart failure is tissue engineering. Tissue engineering is a field of research that aims to create living tissues and organs to replace damaged or diseased tissue. The goal of tissue engineering in heart failure is to improve cardiac function and reduce the need for heart transplantation. This can be done using the three important principles of cells, biomaterials and signals to improve function or replace heart tissue. The techniques for using cells and biomaterials such as electrospinning, hydrogel synthesis, decellularization, etc. are diverse. Treating heart failure through tissue engineering is still under development and research, but it is hoped that there will be no transplants or invasive surgeries in the near future. In this study, based on the most important research in recent years, we will examine the power of tissue engineering in the treatment of heart failure.

ROS-responsive hydrogels: from design and additive manufacturing to biomedical applications

Hydrogels with intricate 3D networks and high hydrophilicity have qualities resembling those of biological tissues, making them ideal candidates for use as smart biomedical materials. Reactive oxygen species (ROS) responsive hydrogels are an innovative class of smart hydrogels, and are cross-linked by ROS-responsive modules through covalent interactions, coordination interactions, or supramolecular interactions. Due to the introduction of ROS response modules, this class of hydrogels exhibits a sensitive response to the oxidative stress microenvironment existing in organisms. Simultaneously, due to the modularity of the ROS-responsive structure, ROS-responsive hydrogels can be manufactured on a large scale through additive manufacturing. This review will delve into the design, fabrication, and applications of ROS-responsive hydrogels. The main goal is to clarify the chemical principles that govern the response mechanism of these hydrogels, further providing new perspectives and methods for designing responsive hydrogel materials.

Novel Approach for Cardioprotection: In Situ Targeting of Metformin via Conductive Hydrogel System

Ischemia/reperfusion (I/R) injury following myocardial infarction is a major cause of cardiomyocyte death and impaired cardiac function. Although clinical data show that metformin is effective in repairing cardiac I/R injury, its efficacy is hindered by non-specific targeting during administration, a short half-life, frequent dosing, and potential adverse effects on the liver and kidneys. In recent years, injectable hydrogels have shown substantial potential in overcoming drug delivery challenges and treating myocardial infarction. To this end, we developed a natural polymer hydrogel system comprising methacryloylated chitosan and methacryloylated gelatin modified with polyaniline conductive derivatives. In vitro studies demonstrated that the optimized hydrogel exhibited excellent injectability, biocompatibility, biodegradability, suitable mechanical properties, and electrical conductivity. Incorporating metformin into this hydrogel significantly extended the administration cycle, mitigated mitochondrial damage, decreased abnormal ROS production, and enhanced cardiomyocyte function. Animal experiments indicated that the metformin/hydrogel system reduced arrhythmia incidence, infarct size, and improved cardiac mitochondrial and overall cardiac function, promoting myocardial repair in I/R injury. Overall, the metformin-loaded conductive hydrogel system effectively mitigates mitochondrial oxidative damage and improves cardiomyocyte function, thereby offering a theoretical foundation for the potential application of metformin in cardioprotection.

Gas Therapy: Generating, Delivery, and Biomedical Applications

Oxygen (O2), nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H2S), and hydrogen (H2) with direct effects, and carbon dioxide (CO2) with complementary effects on the condition of various diseases are known as therapeutic gases. The targeted delivery and in situ generation of these therapeutic gases with controllable release at the site of disease has attracted attention to avoid the risk of gas poisoning and improve their performance in treating various diseases such as cancer therapy, cardiovascular therapy, bone tissue engineering, and wound healing. Stimuli-responsive gas-generating sources and delivery systems based on biomaterials that enable on-demand and controllable release are promising approaches for precise gas therapy. This work highlights current advances in the design and development of new approaches and systems to generate and deliver therapeutic gases at the site of disease with on-demand release behavior. The performance of the delivered gases in various biomedical applications is then discussed.

Chemically Programmed Hydrogels for Spatiotemporal Modulation of the Cardiac Pathological Microenvironment

After myocardial infarction (MI), sustained ischemic events induce pathological microenvironments characterized by ischemia-hypoxia, oxidative stress, inflammatory responses, matrix remodeling, and fibrous scarring. Conventional clinical therapies lack spatially targeted and temporally responsive modulation of the infarct microenvironment, leading to limited myocardial repair. Engineered hydrogels have a chemically programmed toolbox for minimally invasive localization of the pathological microenvironment and personalized responsive modulation over different pathological periods. Chemically programmed strategies for crosslinking interactions, interfacial binding, and topological microstructures in hydrogels enable minimally invasive implantation and in situ integration tailored to the myocardium. This enhances substance exchange and signal interactions within the infarcted microenvironment. Programmed responsive polymer networks, intelligent micro/nanoplatforms, and biological therapeutic cues contribute to the formation of microenvironment-modulated hydrogels with precise targeting, spatiotemporal control, and on-demand feedback. Therefore, this review summarizes the features of the MI microenvironment and chemically programmed schemes for hydrogels to conform, integrate, and modulate the cardiac pathological microenvironment. Chemically programmed strategies for oxygen-generating, antioxidant, anti-inflammatory, provascular, and electrointegrated hydrogels to stimulate iterative and translational cardiac tissue engineering are discussed.

ROS-responsive & scavenging NO nanomedicine for vascular diseases treatment by inhibiting endoplasmic reticulum stress and improving NO bioavailability

Vascular diseases seriously threaten human life and health. Exogenous delivery of nitric oxide (NO) represents an effective approach for maintaining vascular homeostasis during pathological events. However, the overproduction of reactive oxygen species (ROS) at vascular injury sites would react with NO to produce damaging peroxynitrite (ONOO-) species and limit the therapeutic effect of NO. Hence, we design a ROS-responsive NO nanomedicine (t-PBA&NO NP) with ROS scavenging ability to solve the dilemma of NO-based therapy. t-PBA&NO NP targets NO and anti-oxidant ethyl caffeate (ECA) to the injury sites via collagen IV homing peptide. The ROS-triggered ROS depletion and ECA release potently alleviate local oxidative stress via ROS scavenging, endoplasmic reticulum and mitochondrial regulation. It subsequently maximizes vascular modulation effects of NO, without production of harmful compounds, reactive nitrogen species (RNS). Therefore, it significantly increases competitiveness of human umbilical vein endothelial cells (HUVECs) over human aortic smooth muscle cells (HASMCs) both in vitro and in vivo. The strategy proved effective in inducing faster re-endothelialization, inhibiting neointimal formation and restoring vascular homeostasis. The synergy between ROS depletion and NO therapy served as a new inspiration for the treatment of cardiovascular diseases and other ROS-associated illnesses.

Intramyocardial delivery of injectable hydrogel with arctigenin alleviated myocardial ischemia-reperfusion injury in rats

Arctigenin belongs to a major bioactive component of Fructus arctii and has been found with cardioprotective effects on rats with ischemia‒reperfusion (I/R) injury. The application of arctigenin is limited due to poor water solubility and low bioavailability. Hydrogel drug delivery systems can improve the efficacy and safety of drugs, increase drug utilization, and reduce side effects. We hypothesized that hydrogels containing arctigenin would facilitate the effect of arctigenin and alleviate I/R injury in the rat heart. Presently, adult Sprague-Dawley (SD) rats were subjected to 1 h of I/R injury, then hydrogels comprising arctigenin were implanted into the myocardium of rats. Triphenyl tetrazolium chloride staining, hematoxylin-eosin staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining and Western blot were performed for evaluating the infarct size, histopathological, and vital protein alterations of hearts. It was discovered that the hydrogel combined with arctigenin abated apoptosis and reduced infarct size. In addition, the results of echocardiography and Masson staining suggested that the hydrogel with arctigenin improved cardiac function, restrained myocardial fibrosis, and activated AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1). Collectively, the injectable hydrogel delivery system enhances the effect of arctigenin, which may play a protective role in I/R injury by activating AMPK and SIRT1.

Protective effects of the bioactive peptide from maggots against skin flap ischemia‒reperfusion injury in rats

Ischemia‒reperfusion (I/R) injury is a frequently observed complication after flap surgery, and it affects skin flap survival and patient prognosis. Currently, there are no proven safe and effective treatment options to treat skin flap I/R injury. Herein, the potential efficacies of the bioactive peptide from maggots (BPM), as well as its underlying mechanisms, were explored in a rat model of skin flap I/R injury and LPS- or H2O2-elicited RAW 264.7 cells. We demonstrated that BPM significantly ameliorated the area of flap survival, and histological changes in skin tissue in vivo. Furthermore, BPM could markedly restore or enhance Nrf2 and HO-1 levels, and suppress the expression of pro-inflammatory cytokines, including TLR4, p-IκB, NFκB p65, p-p65, IL-6, and TNF-α in I/R-injured skin flaps. In addition, BPM treatment exhibited excellent biocompatibility with an adequate safety profile, while it exhibited superior ROS-scavenging ability and the upregulation of antioxidant enzymes in vitro. Mechanistically, the above benefits related to BPM involved the activation of Nrf2/HO-1 and suppression of TLR4/NF-κB pathway. Taken together, this study may provide a scientific basis for the potential therapeutic effect of BPM in the prevention of skin flap I/R injury and other related diseases.

A cigarette filter-derived biomimetic cardiac niche for myocardial infarction repair

Cell implantation offers an appealing avenue for heart repair after myocardial infarction (MI). Nevertheless, the implanted cells are subjected to the aberrant myocardial niche, which inhibits cell survival and maturation, posing significant challenges to the ultimate therapeutic outcome. The functional cardiac patches (CPs) have been proved to construct an elastic conductive, antioxidative, and angiogenic microenvironment for rectifying the aberrant microenvironment of the infarcted myocardium. More importantly, inducing implanted cardiomyocytes (CMs) adapted to the anisotropic arrangement of myocardial tissue by bioengineered structural cues within CPs are more conducive to MI repair. Herein, a functional Cig/(TA-Cu) CP served as biomimetic cardiac niche was fabricated based on structural anisotropic cigarette filter by modifying with tannic acid (TA)-chelated Cu2+ (TA-Cu complex) via a green method. This CP possessed microstructural anisotropy, electrical conductivity and mechanical properties similar to natural myocardium, which could promote elongation, orientation, maturation, and functionalization of CMs. Besides, the Cig/(TA-Cu) CP could efficiently scavenge reactive oxygen species, reduce CM apoptosis, ultimately facilitating myocardial electrical integration, promoting vascular regeneration and improving cardiac function. Together, our study introduces a functional CP that integrates multimodal cues to create a biomimetic cardiac niche and provides an effective strategy for cardiac repair.

A snake cathelicidin enhances transcription factor EB-mediated autophagy and alleviates ROS-induced pyroptosis after ischaemia-reperfusion injury of island skin flaps

BACKGROUND AND PURPOSE

Ischaemia-reperfusion (I/R) injury is a major contributor to skin flap necrosis, which presents a challenge in achieving satisfactory therapeutic outcomes. Previous studies showed that cathelicidin-BF (BF-30) protects tissues from I/R injury. In this investigation, BF-30 was synthesized and its role and mechanism in promoting survival of I/R-injured skin flaps explored.

EXPERIMENTAL APPROACH

Survival rate analysis and laser Doppler blood flow analysis were used to evaluate I/R-injured flap viability. Western blotting, immunofluorescence, TdT-mediated dUTP nick end labelling (TUNEL) and dihydroethidium were utilized to examine the levels of apoptosis, pyroptosis, oxidative stress, transcription factor EB (TFEB)-mediated autophagy and molecules related to the adenosine 5'-monophosphate-activated protein kinase (AMPK)-transient receptor potential mucolipin 1 (TRPML1)-calcineurin signalling pathway.

KEY RESULTS

The outcomes revealed that BF-30 enhanced I/R-injured island skin flap viability. Autophagy, oxidative stress, pyroptosis and apoptosis were related to the BF-30 capability to enhance I/R-injured flap survival. Improved autophagy flux and tolerance to oxidative stress promoted the inhibition of apoptosis and pyroptosis in vascular endothelial cells. Activation of TFEB increased autophagy and inhibited endothelial cell oxidative stress in I/R-injured flaps. A reduction in TFEB level led to a loss of the protective effect of BF-30, by reducing autophagy flux and increasing the accumulation of reactive oxygen species (ROS) in endothelial cells. Additionally, BF-30 modulated TFEB activity via the AMPK-TRPML1-calcineurin signalling pathway.

CONCLUSION AND IMPLICATIONS

BF-30 promotes I/R-injured skin flap survival by TFEB-mediated up-regulation of autophagy and inhibition of oxidative stress, which may have possible clinical applications.

Nanointegrative Glycoengineering-Activated Necroptosis of Triple Negative Breast Cancer Stem Cells Enables Self-Amplifiable Immunotherapy for Systemic Tumor Rejection

Triple-negative breast cancer stem cells (TCSCs) are considered as the origin of recurrence and relapse. It is difficult to kill not only for its resistance, but also the lacking of targetable molecules on membrane. Here, it is confirmed that ST6 β-galactoside alpha-2,6-sialyltransferase 1 (ST6Gal-1) is highly expressed in TCSCs that may be the key enzyme involved in glycoengineering via sialic acid (SA) metabolism. SA co-localizes with a microdomain on cell membrane termed as lipid rafts that enrich CSCs marker and necroptosis proteins mixed lineage kinase domain-like protein (MLKL), suggesting that TCSCs may be sensitive to necroptosis. Thus, the triacetylated N-azidoacetyl-d-mannosamine (Ac3ManNAz) is synthesized as the glycoengineering substrate and applied to introduce artificial azido receptors, dibenzocyclooctyne (DBCO)-modified liposome is used to deliver Compound 6i (C6), a receptor-interacting serine/threonine protein kinase 1(RIPL1)-RIP3K-mixed lineage kinase domain-like protein(MLKL) activator, to induce necroptosis. The pro-necroptosis effect is aggravated by nitric oxide (NO), which is released from NO-depot of cholesterol-NO integrated in DBCO-PEG-liposome@NO/C6 (DLip@NO/C6). Together with the immunogenicity of necroptosis that releases high mobility group box 1(HMGB1) of damage-associated molecular patterns, TCSCs are significantly killed in vitro and in vivo. The results suggest a promising strategy to improve the therapeutic effect on the non-targetable TCSCs with high expression of ST6Gal-1 via combination of glycoengineering and necroptosis induction.

Antimicrobial research of carbohydrate polymer- and protein-based hydrogels as reservoirs for the generation of reactive oxygen species: A review

Reactive oxygen species (ROS) play an important role in biological milieu. Recently, the rapid growth in our understanding of ROS and their promise in antibacterial applications has generated tremendous interest in the combination of ROS generators with bulk hydrogels. Hydrogels represent promising supporters for ROS generators and can locally confine the nanoscale distribution of ROS generators whilst also promoting cellular integration via biomaterial-cell interactions. This review highlights recent efforts and progress in developing hydrogels derived from biological macromolecules with embedded ROS generators with a focus on antimicrobial applications. Initially, an overview of passive and active antibacterial hydrogels is provided to show the significance of proper hydrogel selection and design. These are followed by an in-depth discussion of the various approaches for ROS generation in hydrogels. The structural engineering and fabrication of ROS-laden hydrogels are given with a focus on their biomedical applications in therapeutics and diagnosis. Additionally, we discuss how a compromise needs to be sought between ROS generation and removal for maximizing the efficacy of therapeutic treatment. Finally, the current challenges and potential routes toward commercialization in this rapidly evolving field are discussed, focusing on the potential translation of laboratory research outcomes to real-world clinical outcomes.

Smart Hydrogels for Tissue Regeneration

The rapid growth in the portion of the aging population has led to a consequent increase in demand for biomedical hydrogels, together with an assortment of challenges that need to be overcome in this field. Smart hydrogels can autonomously sense and respond to the physiological/pathological changes of the tissue microenvironment and continuously adapt the response according to the dynamic spatiotemporal shifts in conditions. This along with other favorable properties, make smart hydrogels excellent materials for employing toward improving the precision of treatment for age-related diseases. The key factor during the smart hydrogel design is on accurately identifying the characteristics of natural tissues and faithfully replicating the composition, structure, and biological functions of these tissues at the molecular level. Such hydrogels can accurately sense distinct physiological and external factors such as temperature and biologically active molecules, so they may in turn actively and promptly adjust their response, by regulating their own biological effects, thereby promoting damaged tissue repair. This review summarizes the design strategies employed in the creation of smart hydrogels, their response mechanisms, as well as their applications in field of tissue engineering; and concludes by briefly discussing the relevant challenges and future prospects.

Hydrogels for the Treatment of Myocardial Infarction: Design and Therapeutic Strategies

Cardiovascular diseases (CVDs) have become the leading global burden of diseases in recent years and are the primary cause of human mortality and loss of healthy life expectancy. Myocardial infarction (MI) is the top cause of CVDs-related deaths, and its incidence is increasing worldwide every year. Recently, hydrogels have garnered great interest from researchers as a promising therapeutic option for cardiac tissue repair after MI. This is due to their excellent properties, including biocompatibility, mechanical properties, injectable properties, anti-inflammatory properties, antioxidant properties, angiogenic properties, and conductive properties. This review discusses the advantages of hydrogels as a novel treatment for cardiac tissue repair after MI. The design strategies of various hydrogels in MI treatment are then summarized, and the latest research progress in the field is classified. Finally, the future perspectives of this booming field are also discussed at the end of this review.

Itaconate and citrate releasing polymer attenuates foreign body response in biofabricated cardiac patches

Application of cardiac patches to the heart surface can be undertaken to provide support and facilitate regeneration of the damaged cardiac tissue following ischemic injury. Biomaterial composition is an important consideration in the design of cardiac patch materials as it governs host response to ultimately prevent the undesirable fibrotic response. Here, we investigate a novel patch material, poly (itaconate-co-citrate-co-octanediol) (PICO), in the context of cardiac implantation. Citric acid (CA) and itaconic acid (ITA), the molecular components of PICO, provided a level of protection for cardiac cells during ischemic reperfusion injury in vitro. Biofabricated PICO patches were shown to degrade in accelerated and hydrolytic conditions, with CA and ITA being released upon degradation. Furthermore, the host response to PICO patches after implantation on rat epicardium in vivo was explored and compared to two biocompatible cardiac patch materials, poly (octamethylene (anhydride) citrate) (POMaC) and poly (ethylene glycol) diacrylate (PEGDA). PICO patches resulted in less macrophage infiltration and lower foreign body giant cell reaction compared to the other materials, with corresponding reduction in smooth muscle actin-positive vessel infiltration into the implant region. Overall, this work demonstrates that PICO patches release CA and ITA upon degradation, both of which demonstrate cardioprotective effects on cardiac cells after ischemic injury, and that PICO patches generate a reduced inflammatory response upon implantation to the heart compared to other materials, signifying promise for use in cardiac patch applications.

Transcriptomic analysis reveals the lipid metabolism-related gene regulatory characteristics and potential therapeutic agents for myocardial ischemia-reperfusion injury

Background

Impaired energy balance caused by lipid metabolism dysregulation is an essential mechanism of myocardial ischemia-reperfusion injury (MI/RI). This study aims to explore the lipid metabolism-related gene (LMRG) expression patterns in MI/RI and to find potential therapeutic agents.

Methods

Differential expression analysis was performed to screen the differentially expressed genes (DEGs) and LMRGs in the MI/RI-related dataset GSE61592. Enrichment and protein-protein interaction (PPI) analyses were performed to identify the key signaling pathways and genes. The expression trends of key LMRGs were validated by external datasets GSE160516 and GSE4105. The corresponding online databases predicted miRNAs, transcription factors (TFs), and potential therapeutic agents targeting key LMRGs. Finally, the identified LMRGs were confirmed in the H9C2 cell hypoxia-reoxygenation (H/R) model and the mouse MI/RI model.

Results

Enrichment analysis suggested that the "lipid metabolic process" was one of the critical pathways in MI/RI. Further differential expression analysis and PPI analysis identified 120 differentially expressed LMRGs and 15 key LMRGs. 126 miRNAs, 55 TFs, and 51 therapeutic agents were identified targeting these key LMRGs. Lastly, the expression trends of Acadm, Acadvl, and Suclg1 were confirmed by the external datasets, the H/R model and the MI/RI model.

Conclusion

Acadm, Acadvl, and Suclg1 may be the key genes involved in the MI/RI-related lipid metabolism dysregulation; and acting upon these factors may serve as a potential therapeutic strategy.

Biomaterials-Based Antioxidant Strategies for the Treatment of Oxidative Stress Diseases

Oxidative stress is characterized by an increase in reactive oxygen species or a decrease in antioxidants in the body. This imbalance leads to detrimental effects, including inflammation and multiple chronic diseases, ranging from impaired wound healing to highly impacting pathologies in the neural and cardiovascular systems, or the bone, amongst others. However, supplying compounds with antioxidant activity is hampered by their low bioavailability. The development of biomaterials with antioxidant capacity is poised to overcome this roadblock. Moreover, in the treatment of chronic inflammation, material-based strategies would allow the controlled and targeted release of antioxidants into the affected tissue. In this review, we revise the main causes and effects of oxidative stress, and survey antioxidant biomaterials used for the treatment of chronic wounds, neurodegenerative diseases, cardiovascular diseases (focusing on cardiac infarction, myocardial ischemia-reperfusion injury and atherosclerosis) and osteoporosis. We anticipate that these developments will lead to the emergence of new technologies for tissue engineering, control of oxidative stress and prevention of diseases associated with oxidative stress.