An injectable conductive hydrogel with dual responsive release of rosmarinic acid improves cardiac function and promotes repair after myocardial infarction

Fish Swim Bladder-Derived ECM Hydrogels Effectively Treat Myocardial Ischemic Injury through Immunomodulation and Angiogenesis

Injectable hydrogel implants represent a promising therapeutic approach for ischemic heart failure; but their efficacy is often limited by low bioactivity, poor durability, and inadequate injection techniques. Herein, a unique hydrogel incorporating extracellular matrix from fish swim bladder (FSB-ECM), which has distinct advantages over mammalian derived ECM, such as low antigenicity, bioactivity, and source safety, is developed. It consists of collagen, glycoproteins, and proteoglycans, including 13 proteins common in the myocardial matrix and three specific proteins: HSPG, Col12a1, and vWF. This hydrogel enhances cardiac cell adhesion and stretching while promoting angiogenesis and M2 macrophage polarization. In addition, its storage modulus (G') increases over time, reaching about 1000 Pa after 5 min, which facilitates transcatheter delivery and in situ gelling. Furthermore, this hydrogel provides sustained support for cardiac contractions, exhibiting superior longevity. In a rat model of ischemic heart failure, the ejection fraction significantly improves with FSB-ECM treatment, accompanied by increased angiogenesis, reduced inflammation, and decreased infarct size. Finally, RNA sequencing combined with in vitro assays identifies ANGPTL4 as a key protein involved in mediating the effects of FSB-ECM treatment. Overall, this new injectable hydrogel based on FSB-ECM is suitable for transcatheter delivery and possesses remarkable reparative capabilities for treating heart failure.

Injection of ROS-Responsive Hydrogel Loaded with IL-1β-targeted nanobody for ameliorating myocardial infarction

The cardiac microenvironment profoundly restricts the efficacy of myocardial regeneration tactics for the treatment of myocardial infarction (MI). A prospective approach for MI therapeutics encompasses the combined strategy of scavenging reactive oxygen species (ROS) to alleviate oxidative stress injury and facilitating macrophage polarization towards the regenerative M2 phenotype. In this investigation, we fabricated a ROS-sensitive hydrogel engineered to deliver our previously engineered IL-1β-VHH for myocardial restoration. In mouse and rat models of myocardial infarction, the therapeutic gel was injected into the pericardial cavity, effectively disseminated over the heart surface, forming an in situ epicardial patch. The IL-1β-VHH released from the hydrogel exhibited penetrative potential into the myocardium. Our results imply that this infarct-targeting gel can adhere to the damaged cardiac tissue and augment the quantity of anti-IL-1β antibodies. Moreover, the anti-IL-1β hydrogel safeguards cardiomyocytes from apoptosis by neutralizing IL-1β and inducing M2-type polarization within the myocardial infarction regions, thereby facilitating therapeutic cardiac repair. Our results emphasize the effectiveness of this synergistic comprehensive treatment modality in the management of MI and showcase its considerable potential for promoting recovery in infarcted hearts.

Injectable hydrogels with ROS-triggered drug release enable the co-delivery of antibacterial agent and anti-inflammatory nanoparticle for periodontitis treatment

Periodontitis, a chronic inflammatory disease caused by bacteria, is characterized by localized reactive oxygen species (ROS) accumulation, leading to an inflammatory response, which in turn leads to the destruction of periodontal supporting tissues. Therefore, antibacterial, scavenging ROS, reducing the inflammatory response, regulating periodontal microenvironment, and alleviating alveolar bone resorption are effective methods to treat periodontitis. In this study, we developed a ROS-responsive injectable hydrogel by modifying hyaluronic acid with 3-amino phenylboronic acid (PBA) and reacting it with poly(vinyl alcohol) (PVA) to form a borate bond. In addition, the ROS-responsive hydrogel encapsulated the antibacterial agent minocycline hydrochloride (MH) and Fe-Quercetin anti-inflammatory nanoparticles (Fe-Que NPs) for on-demand drug release in response to the periodontitis microenvironment. This hydrogel (HP-PVA@MH/Fe-Que) exhibited highly effective antibacterial properties. Moreover, by modulating the Nrf2/NF-κB pathway, it effectively eliminated ROS and promoted macrophage polarization to the M2 phenotype, reducing inflammation and enhancing the osteogenic differentiation potential of human periodontal ligament stem cells (hPDLSCs) in the periodontal microenvironment. Animal studies showed that HP-PVA@MH/Fe-Que significantly reduced alveolar bone loss and enhanced osteogenic factor expression by killing bacteria and inhibiting inflammation. Thus, HP-PVA@MH/Fe-Que hydrogel had efficient antibacterial, ROS-scavenging, anti-inflammatory, and alveolar bone resorption-alleviation abilities, showing excellent application potential for periodontitis healing.

Adhesive and Conductive Hydrogels for the Treatment of Myocardial Infarction

Myocardial infarction (MI) is a leading cause of mortality among cardiovascular diseases. Following MI, the damaged myocardium is progressively being replaced by fibrous scar tissue, which exhibits poor electrical conductivity, ultimately resulting in arrhythmias and adverse cardiac remodeling. Due to their extracellular matrix-like structure and excellent biocompatibility, hydrogels are emerging as a focal point in cardiac tissue engineering. However, traditional hydrogels lack the necessary conductivity to restore electrical signal transmission in the infarcted regions. Imparting conductivity to hydrogels while also enhancing their adhesive properties enables them to adhere closely to myocardial tissue, establish stable electrical connections, and facilitate synchronized contraction and myocardial tissue repair within the infarcted area. This paper reviews the strategies for constructing conductive and adhesive hydrogels, focusing on their application in MI repair. Furthermore, the challenges and future directions in developing adhesive and conductive hydrogels for MI repair are discussed.

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.

Enhancing cardiac repair post-myocardial infarction: a study on GATM/Gel hydrogel therapeutics

BACKGROUND AND PURPOSE

Significant advancements in therapeutic approaches are imperative to address the prevalent impact of myocardial infarction (MI) on morbidity and mortality rates worldwide. This study explores the therapeutic potential of GATM/Gel hydrogel, focusing on its ability to enhance cardiac repair and functionality after MI through modulation of inflammatory and repair pathways.

EXPERIMENTAL APPROACH

The effects of GATM/Gel hydrogel on cardiac recovery were studied in a murine MI model. HA-CHO and gelatin solutions were mixed in situ using a dual syringe with a static mixing needle, and the resulting hydrogel was applied directly to the epicardium during MI modeling, followed by repositioning of the heart and closure of the thorax. Comprehensive in vivo assessments-including echocardiography, electrocardiography, and histopathological analysis-were combined with molecular techniques such as RT-qPCR, Western blotting, and immunofluorescence to elucidate the underlying mechanisms. Key cellular and molecular changes were tracked, focusing on macrophage polarization, angiogenesis, and modulation of the TNF/TNFR2 signaling pathway.

KEY RESULTS

Employing the GATM/Gel hydrogel led to a substantial improvement in heart function, shown through enhanced ejection fraction and fractional shortening, and reduced infarction size compared to control groups. Mechanistically, the hydrogel promoted the polarization of anti-inflammatory M2 macrophages and stimulated angiogenesis. Moreover, treatment with GATM/Gel hydrogel altered the TNF/TNFR2 pathway, pivotal in mediating inflammatory responses and facilitating myocardial repair. The discoveries highlight the possibility of GATM/Gel hydrogels as an innovative remedy for MI, providing a twofold role in regulating inflammation and fostering recovery.

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.

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.

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.

Advanced Nanomedicine Approaches for Myocardial Infarction Treatment

Myocardial infarction, usually caused by the rupture of atherosclerotic plaque, leads to irreversible ischemic cardiomyocyte death within hours followed by impaired cardiac performance or even heart failure. Current interventional reperfusion strategies for myocardial infarction still face high mortality with the development of heart failure. Nanomaterial-based therapy has made great progress in reducing infarct size and promoting cardiac repair after MI, although most studies are preclinical trials. This review focuses primarily on recent progress (2016-now) in the development of various nanomedicines in the treatment of myocardial infarction. We summarize these applications with the strategy of mechanism including anti-cardiomyocyte death strategy, activation of neovascularization, antioxidants strategy, immunomodulation, anti-cardiac remodeling, and cardiac repair.

Advances in injectable hydrogels for radiation-induced heart disease

Radiological heart damage (RIHD) is damage caused by unavoidable irradiation of the heart during chest radiotherapy, with a long latency period and a progressively increasing proportion of delayed cardiac damage due to conventional doses of chest radiotherapy. There is a risk of inducing diseases such as acute/chronic pericarditis, myocarditis, delayed myocardial fibrosis and damage to the cardiac conduction system in humans, which can lead to myocardial infarction or even death in severe cases. This paper details the pathogenesis of RIHD and gives potential targets for treatment at the molecular and cellular level, avoiding the drawbacks of high invasiveness and immune rejection due to drug therapy, medical device implantation and heart transplantation. Injectable hydrogel therapy has emerged as a minimally invasive tissue engineering therapy to provide necessary mechanical support to the infarcted myocardium and to act as a carrier for various bioactive factors and cells to improve the cellular microenvironment in the infarcted area and induce myocardial tissue regeneration. Therefore, this paper combines bioactive factors and cellular therapeutic mechanisms with injectable hydrogels, presents recent advances in the treatment of cardiac injury after RIHD with different injectable gels, and summarizes the therapeutic potential of various types of injectable hydrogels as a potential solution.

Silk fibroin and hydroxypropyl cellulose composite injectable hydrogel-containing extracellular vesicles for myocardial infarction repair

Extracellular vesicles (EVs) have been recognized as one of the promising specific drugs for myocardial infarction (MI) prognosis. Nevertheless, low intramyocardial retention of EVs remains a major impediment to their clinical application. In this study, we developed a silk fibroin/hydroxypropyl cellulose (SF/HPC) composite hydrogel combined with AC16 cell-derived EVs targeted modification by folic acid for the treatment of acute myocardial infarction repair. EVs were functionalized by distearoylphosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG-FA) via noncovalent interaction for targeting and accelerating myocardial infarction repair.In vitro, cytocompatibility analyses revealed that the as-prepared hydrogels had excellent cell viability by MTT assay and the functionalized EVs had higher cell migration by scratch assay.In vivo, the composite hydrogels can promote myocardial tissue repair effects by delaying the process of myocardial fibrosis and promoting angiogenesis of infarct area in MI rat model.

Advancing homogeneous networking principles for the development of fatigue-resistant, low-swelling and sprayable hydrogels for sealing wet, dynamic and concealed wounds in vivo

Effective sealing of wet, dynamic and concealed wounds remains a formidable challenge in clinical practice. Sprayable hydrogel sealants are promising due to their ability to cover a wide area rapidly, but they face limitations in dynamic and moist environments. To address this issue, we have employed the principle of a homogeneous network to design a sprayable hydrogel sealant with enhanced fatigue resistance and reduced swelling. This network is formed by combining the spherical structure of lysozyme (LZM) with the orthotetrahedral structure of 4-arm-polyethylene glycol (4-arm-PEG). We have achieved exceptional sprayability by controlling the pH of the precursor solution. The homogeneous network, constructed through uniform cross-linking of amino groups in protein and 4-arm-PEG-NHS, provides the hydrogel with outstanding fatigue resistance, low swelling and sustained adhesion. In vitro testing demonstrated that it could endure 2000 cycles of underwater shearing, while in vivo experiments showed adhesion maintenance exceeding 24 h. Furthermore, the hydrogel excelled in sealing leaks and promoting ulcer healing in models including porcine cardiac hemorrhage, lung air leakage and rat oral ulcers, surpassing commonly used clinical materials. Therefore, our research presents an advanced biomaterial strategy with the potential to advance the clinical management of wet, dynamic and concealed wounds.

Injectable Nano-Micro Composites with Anti-bacterial and Osteogenic Capabilities for Minimally Invasive Treatment of Osteomyelitis

The effective management of osteomyelitis remains extremely challenging due to the difficulty associated with treating bone defects, the high probability of recurrence, the requirement of secondary surgery or multiple surgeries, and the difficulty in eradicating infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Hence, smart biodegradable biomaterials that provide effective and precise local anti-infection effects and can promote the repair of bone defects are actively being developed. Here, a novel nano-micro composite is fabricated by combining calcium phosphate (CaP) nanosheets with drug-loaded GelMA microspheres via microfluidic technology. The microspheres are covalently linked with vancomycin (Van) through an oligonucleotide (oligo) linker using an EDC/NHS carboxyl activator. Accordingly, a smart nano-micro composite called "CaP@MS-Oligo-Van" is synthesized. The porous CaP@MS-Oligo-Van composites can target and capture bacteria. They can also release Van in response to the presence of bacterial micrococcal nuclease and Ca2+, exerting additional antibacterial effects and inhibiting the inflammatory response. Finally, the released CaP nanosheets can promote bone tissue repair. Overall, the findings show that a rapid, targeted drug release system based on CaP@MS-Oligo-Van can effectively target bone tissue infections. Hence, this agent holds potential in the clinical treatment of osteomyelitis caused by MRSA.

Exoskeleton Partial-Coated Stem Cells for Infarcted Myocardium Restoring

The integration of abiotic materials with live cells has emerged as an exciting strategy for the control of cellular functions. Exoskeletons consisting ofmetal-organic frameworks are generated to produce partial-coated bone marrow stem cells (BMSCs) to overcome low cell survival leading to disappointing effects for cell-based cardiac therapy. Partially coated exoskeletons can promote the survival of suspended BMSCs by integrating the support of exoskeletons and unimpaired cellular properties. In addition, partial exoskeletons exhibit protective effects against detrimental environmental conditions, including reactive oxygen species, pH changes, and osmotic pressure. The partial-coated cells exhibit increased intercellular adhesion forces to aggregate and adhere, promoting cell survival and preventing cell escape during cell therapy. The exoskeletons interact with cell surface receptors integrin α5β1, leading to augmented biological functions with profitable gene expression alteration, such as Vegfa, Cxcl12, and Adm. The partial-coated BMSCs display enhanced cell retention in infarcted myocardium through non-invasive intravenous injections. The repair of myocardial infarction has been achieved with improved cardiac function, myocardial angiogenesis, proliferation, and inhibition of cell apoptosis. This discovery advances the elucidation of potential molecular and cellular mechanisms for cell-exoskeleton interactions and benefits the rational design and manufacture of next-generation nanobiohybrids.