Targeted repair of heart injury by stem cells fused with platelet nanovesicles

Enhanced Proliferation of Visualizable Mesenchymal Stem Cell-Platelet Hybrid Cell for Versatile Intracerebral Hemorrhage Treatment

The intrinsic features and functions of platelets and mesenchymal stem cells (MSCs) indicate their great potential in the treatment of intracerebral hemorrhage (ICH). However, neither of them can completely overcome ICH because of the stealth process and the complex pathology of ICH. Here, we fabricate hybrid cells for versatile and highly efficient ICH therapy by fusing MSCs with platelets and loading with lysophosphatidic acid-modified PbS quantum dots (LPA-QDs). The obtained LPA-QDs@FCs (FCs = fusion cells) not only inherit the capabilities of both platelets and MSCs but also exhibit clearly enhanced proliferation activated by LPA. After systemic administration, many proliferating LPA-QDs@FCs rapidly accumulate in ICH areas for responding to the vascular damage and inflammation and then efficiently prevent both the primary and secondary injuries of ICH but with no obvious side effects. Moreover, the treatment process can be tracked by near-infrared II fluorescence imaging with highly spatiotemporal resolution, providing a promising solution for ICH therapy.

Nanomedicines for cardiovascular disease

The leading cause of death in the world, cardiovascular disease (CVD), remains a formidable condition for researchers, clinicians and patients alike. CVD comprises a broad collection of diseases spanning the heart, the vasculature and the blood that runs through and interconnects them. Limitations in CVD therapeutic and diagnostic landscapes have generated excitement for advances in nanomedicine, a field focused on improving patient outcomes through transformative therapies, imaging agents and ex vivo diagnostics. CVD nanomedicines are fundamentally shaped by their intended clinical application, including (1) cardiac or heart-related biomaterials, which can be functionally (for example, mechanically, immunologically, electrically) improved by incorporating nanomaterials; (2) the vasculature, involving systemically injected nanotherapeutics and imaging nanodiagnostics, nano-enabled biomaterials or tissue-nanoengineered solutions; and (3) improving the sensitivity and/or specificity of ex vivo diagnostic devices for patient samples. While immunotherapy has developed into a key pillar of oncology in the past dozen years, CVD immunotherapy and immunoimaging are recently emergent and likely to factor substantially in CVD management in the coming decade. The nanomaterials in CVD-related clinical trials and many promising preclinical strategies indicate that nanomedicine is on the cusp of greatly impacting patients with CVD. Here we review these recent advances, highlighting key clinical opportunities in the rapidly emerging field of CVD nanomedicine.

Bridging the Gap between Nonliving Matter and Cellular Life

A cell, the fundamental unit of life, contains the requisite blueprint information necessary to survive and to build tissues, organs, and systems, eventually forming a fully functional living creature. A slight structural alteration can result in data misprinting, throwing the entire life process off balance. Advances in synthetic biology and cell engineering enable the predictable redesign of biological systems to perform novel functions. Individual functions and fundamental processes at the core of the biology of cells can be investigated by employing a synthetically constrained micro or nanoreactor. However, constructing a life-like structure from nonliving building blocks remains a considerable challenge. Chemical compartments, cascade signaling, energy generation, growth, replication, and adaptation within micro or nanoreactors must be comparable with their biological counterparts. Although these reactors currently lack the power and behavioral sophistication of their biological equivalents, their interface with biological systems enables the development of hybrid solutions for real-world applications, such as therapeutic agents, biosensors, innovative materials, and biochemical microreactors. This review discusses the latest advances in cell membrane-engineered micro or nanoreactors, as well as the limitations associated with high-throughput preparation methods and biological applications for the real-time modulation of complex pathological states.

Application of Nanomaterials in Stem Cell-Based Therapeutics for Cardiac Repair and Regeneration

Cardiovascular disease is a leading cause of disability and death worldwide. Although the survival rate of patients with heart diseases can be improved with contemporary pharmacological treatments and surgical procedures, none of these therapies provide a significant improvement in cardiac repair and regeneration. Stem cell-based therapies are a promising approach for functional recovery of damaged myocardium. However, the available stem cells are difficult to differentiate into cardiomyocytes, which result in the extremely low transplantation efficiency. Nanomaterials are widely used to regulate the myocardial differentiation of stem cells, and play a very important role in cardiac tissue engineering. This study discusses the current status and limitations of stem cells and cell-derived exosomes/micro RNAs based cardiac therapy, describes the cardiac repair mechanism of nanomaterials, summarizes the recent advances in nanomaterials used in cardiac repair and regeneration, and evaluates the advantages and disadvantages of the relevant nanomaterials. Besides discussing the potential clinical applications of nanomaterials in cardiac therapy, the perspectives and challenges of nanomaterials used in stem cell-based cardiac repair and regeneration are also considered. Finally, new research directions in this field are proposed, and future research trends are highlighted.

Tuning the Extracellular Vesicles Membrane through Fusion for Biomedical Applications

Membrane fusion is one of the key phenomena in the living cell for maintaining the basic function of life. Extracellular vesicles (EVs) have the ability to transfer information between cells through plasma membrane fusion, making them a promising tool in diagnostics and therapeutics. This study explores the potential applications of natural membrane vesicles, EVs, and their fusion with liposomes, EVs, and cells and introduces methodologies for enhancing the fusion process. EVs have a high loading capacity, bio-compatibility, and stability, making them ideal for producing effective drugs and diagnostics. The unique properties of fused EVs and the crucial design and development procedures that are necessary to realize their potential as drug carriers and diagnostic tools are also examined. The promise of EVs in various stages of disease management highlights their potential role in future healthcare.

Chemically engineering cells for precision medicine

Cell-based therapy holds great potential to address unmet medical needs and revolutionize the healthcare industry, as demonstrated by several therapeutics such as CAR-T cell therapy and stem cell transplantation that have achieved great success clinically. Nevertheless, natural cells are often restricted by their unsatisfactory in vivo trafficking and lack of therapeutic payloads. Chemical engineering offers a cost-effective, easy-to-implement engineering tool that allows for strengthening the inherent favorable features of cells and confers them new functionalities. Moreover, in accordance with the trend of precision medicine, leveraging chemical engineering tools to tailor cells to accommodate patients individual needs has become important for the development of cell-based treatment modalities. This review presents a comprehensive summary of the currently available chemically engineered tools, introduces their application in advanced diagnosis and precision therapy, and discusses the current challenges and future opportunities.

Exosomes and ultrasound: The future of theranostic applications

Biomaterials and pertaining formulations have been very successful in various diagnostic and therapeutic applications because of its ability to overcome pharmacological limitations. Some of them have gained significant focus in the recent decade for their theranostic properties. Exosomes can be grouped as biomaterials, since they consist of various biological micro/macromolecules and possess all the properties of a stable biomaterial with size in nano range. Significant research has gone into isolation and exploitation of exosomes as potential theranostic agent. However, the limitations in terms of yield, efficacy, and target specificity are continuously being addressed. On the other hand, several nano/microformulations are responsive to physical or chemical alterations and were successfully stimulated by tweaking the physical characteristics of the surrounding environment they are in. Some of them are termed as photodynamic, sonodynamic or thermodynamic therapeutic systems. In this regard, ultrasound and acoustic systems were extensively studied for its ability towards altering the properties of the systems to which they were applied on. In this review, we have detailed about the diagnostic and therapeutic applications of exosomes and ultrasound separately, consisting of their conventional applications, drawbacks, and developments for addressing the challenges. The information were categorized into various sections that provide complete overview of the isolation strategies and theranostic applications of exosomes in various diseases. Then the ultrasound-based disease diagnosis and therapy were elaborated, with special interest towards the use of ultrasound in enhancing the efficacy of nanomedicines and nanodrug delivery systems, Finally, we discussed about the ability of ultrasound in enhancing the diagnostic and therapeutic properties of exosomes, which could be the future of theranostics.

Nanoparticle Based Cardiac Specific Drug Delivery

Heart failure secondary to myocardial injuries is a leading cause of death worldwide. Recently, a growing number of novel therapies have emerged for injured myocardium repairment. However, delivering therapeutic agents specifically to the injured heart remains a significant challenge. Nanoparticles are the most commonly used vehicles for targeted drug delivery. Various nanoparticles have been synthesized to deliver drugs and other therapeutic molecules to the injured heart via passive or active targeting approaches, and their targeting specificity and therapeutic efficacies have been investigated. Here, we summarized nanoparticle-based, cardiac-specific drug delivery systems, their potency for treating heart diseases, and the mechanisms underlying these cardiac-targeting strategies. We also discussed the clinical studies that have employed nanoparticle-based cardiac-specific drug delivery.

Thrombus-specific/responsive biomimetic nanomedicine for spatiotemporal thrombolysis and alleviation of myocardial ischemia/reperfusion injury

Acute myocardial infarction (AMI) is usually caused by coronary thrombosis. However, the short half-life, lack of targetability and inevitable ischemia/reperfusion injury secondary to revascularization, which characterizes tissue plasminogen activator (tPA) limit its thrombolytic efficacy for AMI. To address the targeted and site-specific delivery of tPA, the current study reports the construction of a thrombus-targeting and responsive biomimetic nanoparticle (PTPN) for spatiotemporal treatment of AMI. PTPN was constituted by the thrombus microenvironment- responsive phenylboronic acid (PBA) nanocarrier, antioxidant molecular protocatechualdehyde (PC) and tPA with thrombolytic effect, which were enclosed by the platelet membrane. The thrombus-targeting capability of the platelet membrane enabled the adhesion of PTPN to damaged endothelial cells. The nanoparticle disintegrated under slightly acid condition and re-opened the infarct-related artery during the period of ischemia. Sequentially, ROS induced by blood reperfusion was eliminated by PC released from particle disintegration, and the cardiomyocyte mitochondrial function was protected from reperfusion injury. Therefore, this thrombus-specific/responsive biomimetic nanomedicine provides a spatiotemporal paradigm for AMI treatment with promising clinical translation prospects.

Extracellular-Vesicle-Based Drug Delivery Systems for Enhanced Antitumor Therapies through Modulating the Cancer-Immunity Cycle

Although immunotherapy harnessing activity of the immune system against tumors has made great progress, the treatment efficacy remains limited in most cancers. Current anticancer immunotherapy is primarily based on T-cell-mediated cellular immunity, which highly relies on efficiency of triggering the cancer-immunity cycle, namely, tumor antigen release, antigen presentation by antigen presenting cells, T cell activation, recruitment and infiltration of T cells into tumors, and recognition and killing of tumor cells by T cells. Unfortunately, these immunotherapies are restricted by inefficient drug delivery and acting on only a single step of the cancer-immunity cycle. Due to high biocompatibility, low immunogenicity, intrinsic cell targeting, and easy chemical and genetic manipulation, extracellular vesicle (EV)-based drug delivery systems are widely used to amplify anticancer immune responses by serving as an integrated platform for multiple drugs or therapeutic strategies to synergistically activate several steps of cancer-immunity cycle. This review summarizes various mechanisms related to affecting cancer-immunity cycle disorders. Meanwhile, preparation and application of EV-based drug delivery systems in modulating cancer-immunity cycle are introduced, especially in the improvement of T cell recruitment and infiltration into tumors. Finally, opportunities and challenges of EV-based drug delivery systems in translational clinical applications are briefly discussed.

Rescuing Cardiac Cells and Improving Cardiac Function by Targeted Delivery of Oxygen-Releasing Nanoparticles after or Even before Acute Myocardial Infarction

Myocardial infarction (MI) causes massive cell death due to restricted blood flow and oxygen deficiency. Rapid and sustained oxygen delivery following MI rescues cardiac cells and restores cardiac function. However, current oxygen-generating materials cannot be administered during acute MI stage without direct injection or suturing methods, both of which risk rupturing weakened heart tissue. Here, we present infarcted heart-targeting, oxygen-releasing nanoparticles capable of being delivered by intravenous injection at acute MI stage, and specifically accumulating in the infarcted heart. The nanoparticles can also be delivered before MI, then gather at the injured area after MI. We demonstrate that the nanoparticles, delivered either pre-MI or post-MI, enhance cardiac cell survival, stimulate angiogenesis, and suppress fibrosis without inducing substantial inflammation and reactive oxygen species overproduction. Our findings demonstrate that oxygen-delivering nanoparticles can provide a nonpharmacological solution to rescue the infarcted heart during acute MI and preserve heart function.

Bioengineering Extracellular Vesicles for the Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVD) remain one of the leading causes of mortality worldwide. Despite recent advances in diagnosis and interventions, there is still a crucial need for new multifaceted therapeutics that can address the complicated pathophysiological mechanisms driving CVD. Extracellular vesicles (EVs) are nanovesicles that are secreted by all types of cells to transport molecular cargo and regulate intracellular communication. EVs represent a growing field of nanotheranostics that can be leveraged as diagnostic biomarkers for the early detection of CVD and as targeted drug delivery vesicles to promote cardiovascular repair and recovery. Though a promising tool for CVD therapy, the clinical application of EVs is limited by the inherent challenges in EV isolation, standardization, and delivery. Hence, this review will present the therapeutic potential of EVs and introduce bioengineering strategies that augment their natural functions in CVD.

Functional Extracellular Vesicles for Regenerative Medicine

The unique biological characteristics and promising clinical potential of extracellular vesicles (EVs) have galvanized EV applications for regenerative medicine. Recognized as important mediators of intercellular communication, naturally secreted EVs have the potential, as innate biotherapeutics, to promote tissue regeneration. Although EVs have emerged as novel therapeutic agents, challenges related to the clinical transition have led to further functionalization. In recent years, various engineering approaches such as preconditioning, drug loading, and surface modification have been developed to potentiate the therapeutic outcomes of EVs. Also, limitations of natural EVs have been addressed by the development of artificial EVs that offer advantages in terms of production yield and isolation methodologies. In this review, an updated overview of current techniques is provided for the functionalization of natural EVs and recent advances in artificial EVs, particularly in the scope of regenerative medicine.

Global research trends in extracellular vesicles based on stem cells from 1991 to 2021: A bibliometric and visualized study

Objective: With the development of extracellular vesicles (EVs) based on stem cells research all over the world, our present study was aiming to discover the global trends in this field.

Methods: All publications related to EVs based on stem cells from 1991 to 2021 were collected from the Science Citation Index-Expanded of Web of Science Subsequently, the data were evaluated using the bibliometric methodology. In terms of visualized study, the VOS viewer software was performed to investigate the bibliographic coupling, co-citation, co-authorship, and co-occurrence trends, and last for the publication’s trends involved in the field of EVs based on stem cells.

Results: A total of 8,208 publications were retrieved and the relative number of global publications and research interests were increasing every year especially in recent 5 years. China rank top one in terms of total publications, prolific authors, and funds, whereas the USA made the greatest contributions with the most total citations and highest H-index to the global research. Stem cell research therapy contributed the highest publications, whereas the journal of PLOS ONE showed the best total link strength. The Shanghai Jiao Tong University, University of California System, and Harvard University were the most contributive institutions. The global studies could be divided into six clusters as follows: cancer research, musculoskeletal system research, respiratory system research, urinary system and endocrine system research, nerve system research, and cardiovascular system research. All the directions were predicted to still hotspots in near future researches in this field.

Conclusion: The total number of publications about EVs based stem cells would be increasing according to the current global trends. China and the USA was the largest contributors in this field. Further efforts should be put in the directions of cancer research, musculoskeletal system research, respiratory system research, urinary system and endocrine system research, nerve system research, as well was cardiovascular system research in this field of EVs based stem cells.

Phytochemical natural killer cells reprogram tumor microenvironment for potent immunotherapy of solid tumors

Natural killer cells (NKs) hold great promise in cancer treatment, but their application in solid tumors remains a great challenge because current solutions hardly can overcome various difficulties that faced. Herein, we endow NKs with the phytochemical feature for effective immunotherapy of solid tumors. NKs are decorated with natural thylakoid (Tk) membranes through an efficient and convenient membrane fusion strategy. Tk engineering effectively activates NKs, because the antioxidase on Tk induce glycogen synthase kinase-3β inhibition, and subsequently increase the expression of activating receptor and cytotoxic effector molecules in NKs. After systemic administration, the phytochemical NKs (PC-NKs) can target tumor tissues, and then profoundly reprogram tumor microenvironment (TME) with the help of catalase on Tk, resulting in significantly enhanced direct killing of PC-NKs and immune activated TME. Therefore, potent therapeutic effects with few abnormalities are achieved, providing a novel idea for the development of highly efficient NKs for solid tumors.

Engineering stem cell therapeutics for cardiac repair

Cardiovascular disease is the leading cause of death in the world. Stem cell-based therapies have been widely investigated for cardiac regeneration in patients with heart failure or myocardial infarction (MI) and surged ahead on multiple fronts over the past two decades. To enhance cellular therapy for cardiac regeneration, numerous engineering techniques have been explored to engineer cells, develop novel scaffolds, make constructs, and deliver cells or their derivatives. This review summarizes the state-of-art stem cell-based therapeutics for cardiac regeneration and discusses the emerged bioengineering approaches toward the enhancement of therapeutic efficacy of stem cell therapies in cardiac repair. We cover the topics in stem cell source and engineering, followed by stem cell-based therapies such as cell aggregates and cell sheets, and biomaterial-mediated stem cell therapies such as stem cell delivery with injectable hydrogel, three-dimensional scaffolds, and microneedle patches. Finally, we discuss future directions and challenges of engineering stem cell therapies for clinical translation.

Tregs biomimetic nanoparticle to reprogram inflammatory and redox microenvironment in infarct tissue to treat myocardial ischemia reperfusion injury in mice

Background

At present, patients with myocardial infarction remain an increased risk for myocardial ischemia/reperfusion injury (MI/RI). There lacks effectively method to treat MI/RI in clinic. For the treatment of MI/RI, it is still a bottleneck to effectively deliver drug to ischemic myocardium. In this paper, a regulatory T cells (Tregs) biomimetic nanoparticle (CsA@PPTK) was prepared by camouflaging nanoparticle with platelet membrane.

Results

CsA@PPTK actively accumulated in ischemic myocardium of MI/RI mice. CsA@PPTK significantly scavenged reactive oxygen species (ROS) and increased the generation of Tregs and the ratio of M2 type macrophage to M1 type macrophage in ischemic myocardium. Moreover, CsA@PPTK significantly attenuated apoptosis of cardiomyocytes and reduced the infarct size and fibrosis area in ischemic myocardium. CsA@PPTK markedly decreased the protein expression of MMP-9 and increased the protein expression of CX43 in ischemic myocardium tissue. Subsequently, the remodeling of the left ventricle was significant alleviated, and heart function of MI/RI mice was markedly improved.

Conclusion

CsA@PPTK showed significant therapeutic effect on MI/RI, and it has great potential application in the treatment of MI/RI.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01445-2.

Recent advances in biomaterial-assisted cell therapy

With the outstanding achievement of chimeric antigen receptor (CAR)-T cell therapy in the clinic, cell-based medicines have attracted considerable attention for biomedical applications and thus generated encouraging progress. As the basic construction unit of organisms, cells harbor low immunogenicity, desirable compatibility, and a strong capability of crossing various biological barriers. However, there is still a long way to go to fix significant bottlenecks for their clinical translation, such as facile preparation, strict stability requirements, scale-up manufacturing, off-target toxicity, and affordability. The rapid development of biotechnology and engineering approaches in materials sciences has provided an ideal platform to assist cell-based therapeutics for wide application in disease treatments by overcoming these issues. Herein, we survey the most recent advances of various cells as bioactive ingredients and outline the roles of biomaterials in developing cell-based therapeutics. Besides, a perspective of cell therapies is offered with a particular focus on biomaterial-involved development of cell-based biopharmaceuticals.

Engineered extracellular vesicles and their mimics in cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Current pharmacological interventions for the CVDs suffer from low bioavailability, low retention rate, poor targeting, drug resistance complicated side effects. Extracellular vesicles (EVs), which are lipid vesicles secreted by cells, play key roles in pathological processes of CVDs. Engineered EVs and EV mimics with superior properties can overcome limitations of traditional medicine, thus emerging as alternative therapeutic options for the CVDs. In this Review, we summarized basic concepts of EVs and EV mimics, highlighted engineering strategies, and lastly discussed applications of engineered EVs and EV mimics against the CVDs. We believe this Review can provide some new insights on engineering EVs and EV mimics and facilitate their application in precise control of CVDs.

Minimally invasive delivery of a hydrogel-based exosome patch to prevent heart failure

Coronary heart disease (CHD) has been the number one killer in the United States for decades and causes millions of deaths each year. Clinical treatment of heart ischemic injury relieves symptoms in the acute stage of CHD; however, patients with an infarcted heart muscle can develop heart failure (HF) due to chronic maladaptive remodeling. Regenerative therapy has been studied as a potential treatment option for myocardial infarction (MI) and HF. Cardiac patches have been designed and tested to increase therapeutic retention and integration in this field. However, the delivery usually requires invasive surgical techniques, including open-chest surgeries and heart or pericardium manipulation. Those procedures may cause chronic adhesions between the heart anterior wall and chest wall. This study created and tested an injectable ExoGel by embedding mesenchymal stem cell (MSC) -derived exosomes into hyaluronic acid (HA) hydrogel. ExoGel was injected into the pericardial cavity of rats with transverse aortic constriction (TAC) induced heart failure. ExoGel therapy reduced LV chamber size and preserved wall thickness. The feasibility and safety ExoGel injection was further confirmed in a pig model.

Nanocarrier-Based Targeted Therapies for Myocardial Infarction

Myocardial infarction is a major cause of morbidity and mortality worldwide. Due to poor inherent regeneration of the adult mammalian myocardium and challenges with effective drug delivery, there has been little progress in regenerative therapies. Nanocarriers, including liposomes, nanoparticles, and exosomes, offer many potential advantages for the therapy of myocardial infarction, including improved delivery, retention, and prolonged activity of therapeutics. However, there are many challenges that have prevented the widespread clinical use of these technologies. This review aims to summarize significant principles and developments in the field, with a focus on nanocarriers using ligand-based or cell mimicry-based targeting. Lastly, a discussion of limitations and potential future direction is provided.

Depletion of tumor associated macrophages enhances local and systemic platelet-mediated anti-PD-1 delivery for post-surgery tumor recurrence treatment

Immunosuppressive cells residing in the tumor microenvironment, especially tumor associated macrophages (TAMs), hinder the infiltration and activation of T cells, limiting the anti-cancer outcomes of immune checkpoint blockade. Here, we report a biocompatible alginate-based hydrogel loaded with Pexidartinib (PLX)-encapsulated nanoparticles that gradually release PLX at the tumor site to block colony-stimulating factor 1 receptors (CSF1R) for depleting TAMs. The controlled TAM depletion creates a favorable milieu for facilitating local and systemic delivery of anti-programmed cell death protein 1 (aPD-1) antibody-conjugated platelets to inhibit post-surgery tumor recurrence. The tumor immunosuppressive microenvironment is also reprogrammed by TAM elimination, further promoting the infiltration of T cells into tumor tissues. Moreover, the inflammatory environment after surgery could trigger the activation of platelets to facilitate the release of aPD-1 accompanied with platelet-derived microparticles binding to PD-1 receptors for re-activating T cells. All these results collectively indicate that the immunotherapeutic efficacy against tumor recurrence of both local and systemic administration of aPD-1 antibody-conjugated platelets could be strengthened by local depletion of TAMs through the hydrogel reservoir.

Increased density of tumor associated macrophages has been correlated with tumor recurrence following surgery. Here the authors design an alginate-based hydrogel encapsulating anti-PD-1-conjugated platelets and nanoparticles loaded with the macrophage-depleting CSF-1R inhibitor pexidartinib, showing inhibition of post-surgery tumor recurrence in preclinical models.

Bovine serum albumin-based biomimetic gene complexes with specificity facilitate rapid re-endothelialization for anti-restenosis

Re-endothelialization is a critical problem to inhibit postoperative restenosis, and gene delivery exhibits great potential in rapid endothelialization. Unfortunately, the therapeutic effect is enormously limited by inefficient specificity, poor biocompatibility and in vivo stability owing largely to the complicated in vivo environment. Herein, we developed a series of platelet membrane (PM) cloaked gene complexes based on natural bovine serum albumin (BSA) and polyethyleneimine (PEI). The gene complexes aimed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. Based on BSA and PM coating, these gene complexes exhibited good biocompatibility, stability with serum and robust homing to endothelium-injured site inherited from platelets. Besides, they enhanced the expression of VEGF protein by their high internalization and nucleus accumulation efficiency, and also substantially promoted migration and proliferation of vascular endothelial cells. The biological properties were further optimized via altering PEI and PM content. Finally, rapid recovery of endothelium in a carotid artery injured mouse model (79% re-endothelialization compared with model group) was achieved through two weeks' treatment by the PM cloaked gene complexes. High level of expressed VEGF in vivo was also realized by the gene complexes. Moreover, neointimal hyperplasia (IH) was significantly inhibited by the gene complexes according to in vivo study. The results verified the great potential of the PM cloaked gene complexes in re-endothelialization for anti-restenosis. STATEMENT OF SIGNIFICANCE: Rapid re-endothelialization is a major challenge to inhibit postoperative restenosis. Herein, a series of biodegradable and biocompatible platelet membrane (PM) cloaked gene complexes were designed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. The PM cloaked gene complexes provided high VEGF expression in vascular endothelial cells (VECs), rapid migration and proliferation of VECs and robust homing to endothelium-injured site. In a carotid artery injured mouse model, PM cloaked gene complexes significantly promoted VEGF expression in vivo, accelerated re-endothelialization and inhibited neointimal hyperplasia due to their good biocompatibility and superior specificity. Overall, the optimized PM cloaked gene complexes overcomes multiple obstacles in gene delivery for re-endothelialization and can be a promising candidate for gene delivery and therapy of postoperative restenosis.

Biomimetic Design of Artificial Hybrid Nanocells for Boosted Vascular Regeneration in Ischemic Tissues

Restoration of sufficient blood supply for the treatment of ischemia remains a significant scientific and clinical challenge. Here, a cell-like nanoparticle delivery technology is introduced that is capable of recapitulating multiple cell functions for the spatiotemporal triggering of vascular regeneration. Specifically, a copper-containing protein is successfully prepared using a recombinant protein scaffold based on a de novo design strategy, which facilitates the timely release of nitric oxide and improved accumulation of particles within ischemic tissues. Through closely mimicking physiological cues, the authors demonstrate the benefits of bioactive factors secreted from hypoxic stem cells on promoting angiogenesis. Following this cell-mimicking manner, artificial hybrid nanosized cells (Hynocell) are constructed by integrating the hypoxic stem cell secretome into nanoparticles with surface coatings of cell membranes fused with copper-containing protein. The Hynocell, hybridized with different cell-derived components, provides synergistic effects on targeting ischemic tissues and promoting vascular regeneration in acute hindlimb ischemia and acute myocardial infarction models. This study offers new insights into the utilization of nanotechnology to potentiate the development of cell-free therapeutics.

Direct Detection of Pulmonary Fibrosis by Near-Infrared-Responsive Biomimetic Platelets

Background

Purpose

Methods

Results

Conclusion

Cardiac Remodeling and Repair: Recent Approaches, Advancements, and Future Perspective

The limited ability of mammalian adult cardiomyocytes to proliferate following an injury to the heart, such as myocardial infarction, is a major factor that results in adverse fibrotic and myocardial remodeling that ultimately leads to heart failure. The continued high degree of heart failure-associated morbidity and lethality requires the special attention of researchers worldwide to develop efficient therapeutics for cardiac repair. Recently, various strategies and approaches have been developed and tested to extrinsically induce regeneration and restoration of the myocardium after cardiac injury have yielded encouraging results. Nevertheless, these interventions still lack adequate success to be used for clinical interventions. This review highlights and discusses both cell-based and cell-free therapeutic approaches as well as current advancements, major limitations, and future perspectives towards developing an efficient therapeutic method for cardiac repair.

Ischemic Microenvironment-Responsive Therapeutics for Cardiovascular Diseases

Cardiovascular diseases caused by ischemia are attracting considerable attention owing to its high morbidity and mortality worldwide. Although numerous agents with cardioprotective benefits have been identified, their clinical outcomes are hampered by their low bioavailability, poor drug solubility, and systemic adverse effects. Advances in nanoscience and nanotechnology provide a new opportunity to effectively deliver drugs for treating ischemia-related diseases. In particular, cardiac ischemia leads to a characteristic pathological environment called an ischemic microenvironment (IME), significantly different from typical cardiac regions. These remarkable differences between ischemic sites and normal tissues have inspired the development of stimuli-responsive systems for the targeted delivery of therapeutic drugs to damaged cardiomyocytes. Recently, many biomaterials with intelligent properties have been developed to enhance the therapeutic benefits of drugs for the treatment of myocardial ischemia. Strategies for stimuli-responsive drug delivery and release based on IME include reactive oxygen species, pH-, hypoxia-, matrix metalloproteinase-, and platelet-inspired targeting strategies. In this review, state-of-the-art IME-responsive biomaterials for the treatment of myocardial ischemia are summarized. Perspectives, limitations, and challenges are also discussed for the further development of innovative and effective approaches to treat ischemic diseases with high effectiveness and biocompatibility.

Microbubble Functionalization with Platelet Membrane Enables Targeting and Early Detection of Sepsis-Induced Acute Kidney Injury

The morbidity and mortality of sepsis-induced acute kidney injury (SAKI) remain high. Early detection using molecular ultrasound imaging may reduce mortality and improve the prognosis. Inspired by the intrinsic relationship between platelets and SAKI, platelet membrane-coated hybrid microbubbles (Pla-MBs) are designed for early recognition of SAKI. Pla-MBs are prepared by ultrasound-assisted recombination of liposomes and platelets, consisting of inherent platelet membrane isolated from platelets. By coating with platelet membranes, Pla-MBs are endowed with various adhesive receptors (such as integrin αIIbβ3), providing a benefit for selective adhesion to damaged endothelium in SAKI. In a rat SAKI model, by combining the advantages of molecular ultrasound imaging and platelet membrane, Pla-MBs display platelet-mimicking properties and achieve the early targeted diagnosis of SAKI prior to the regular laboratory markers of kidney function. Moreover, the expression of platelet-binding proteins (von Willebrand factor and fibrinogen) in the kidneys shows consistent results with molecular ultrasound imaging. Together, microbubble functionalization with platelet membranes is diagnostically beneficial for SAKI and might be a promising modality for endothelial injury diseases in the future.

Extruded Mesenchymal Stem Cell Nanovesicles Are Equally Potent to Natural Extracellular Vesicles in Cardiac Repair

Mesenchymal stem cells (MSCs) repair injured tissues mainly through their paracrine actions. One of the important paracrine components of MSC secretomes is the extracellular vesicle (EV). The therapeutic potential of MSC-EVs has been established in various cardiac injury preclinical models. However, the large-scale production of EVs remains a challenge. We sought to develop a scale-up friendly method to generate a large number of therapeutic nanovesicles from MSCs by extrusion. Those extruded nanovesicles (NVs) are miniature versions of MSCs in terms of surface marker expression. The yield of NVs is 20-fold more than that of EVs. In vitro, cell-based assays demonstrated the myocardial protective effects and therapeutic potential of NVs. Intramyocardial delivery of NVs in the injured heart after ischemia-reperfusion led to a reduction in scar sizes and preservation of cardiac functions. Such therapeutic benefits are similar to those injected with natural EVs from the same MSC parental cells. In addition, NV therapy promoted angiogenesis and proliferation of cardiomyocytes in the post-injury heart. In summary, extrusion is a highly efficient method to generate a large quantity of therapeutic NVs that can potentially replace extracellular vesicles in regenerative medicine applications.

Cell-derived extracellular vesicles and membranes for tissue repair

Humans have a limited postinjury regenerative ability. Therefore, cell-derived biomaterials have long been utilized for tissue repair. Cells with multipotent differentiation potential, such as stem cells, have been administered to patients for the treatment of various diseases. Researchers expected that these cells would mediate tissue repair and regeneration through their multipotency. However, increasing evidence has suggested that in most stem cell therapies, the paracrine effect but not cell differentiation or regeneration is the major driving force of tissue repair. Additionally, ethical and safety problems have limited the application of stem cell therapies. Therefore, nonliving cell-derived techniques such as extracellular vesicle (EV) therapy and cell membrane-based therapy to fulfil the unmet demand for tissue repair are important. Nonliving cell-derived biomaterials are safer and more controllable, and their efficacy is easier to enhance through bioengineering approaches. Here, we described the development and evolution from cell therapy to EV therapy and cell membrane-based therapy for tissue repair. Furthermore, the latest advances in nonliving cell-derived therapies empowered by advanced engineering techniques are emphatically reviewed, and their potential and challenges in the future are discussed.

A fluid-powered refillable origami heart pouch for minimally invasive delivery of cell therapies in rats and pigs

BACKGROUND

Cardiac repair after heart injury remains a big challenge and current drug delivery to the heart is suboptimal. Repeated dosing of therapeutics is difficult due to the invasive nature of such procedures.

METHODS

We developed a fluid-driven heart pouch with a memory-shaped microfabricated lattice structure inspired by origami. The origami structure allowed minimally invasive delivery of the pouch to the heart with two small incisions and can be refilled multiple times with the therapeutic of choice.

FINDINGS

We tested the pouch's ability to deliver mesenchymal stem cells (MSCs) in a rodent model of acute myocardial infarction and demonstrated the feasibility of minimally invasive delivery in a swine model. The pouch's semi-permeable membrane successfully protected delivered cells from their surroundings, maintaining their viability while releasing paracrine factors to the infarcted site for cardiac repair.

CONCLUSIONS

In summary, we developed a fluid-driven heart pouch with a memory-shaped microfabricated lattice structure inspired by origami. The origami structure allowed minimally invasive delivery of the pouch to the heart with two small incisions and can be refilled with the therapeutic of choice.

Proteomic basis of modulation of postischemic fibrosis by MSC exosomes

After an ischemic event, there is activation of fibroblasts leading to scar formation. It is critical to limit the profibrotic remodeling and activate the reparative remodeling phase to limit cardiac diastolic dysfunction. Mesenchymal stem cell (MSC) exosomes offer significant protection against ischemia-related systolic dysfunction. Here, we studied if MSC exosomes would offer protection against profibrotic events in mouse hearts subjected to acute ischemia [1 h left coronary artery (LCA) occlusion] or chronic ischemia (7 days LCA occlusion). After acute ischemia, there was activation of inflammatory signals, more in the peri-infarct than in the infarct area, in the saline (vehicle)-treated mice. At the same time, there was expression of cardiac remodeling signals (vimentin, collagens-1 and -3, and fibronectin), more in the infarct area. Treatment with MSC exosomes before LCA ligation suppressed inflammatory signals during acute and chronic ischemia. Furthermore, exosome treatment promoted pro-reparative cardiac extracellular matrix (ECM) remodeling in both infarct and peri-infarct areas by suppressing fibronectin secretion and by modulating collagen secretion to reduce fibrotic scar formation through altered cellular signaling pathways. Proteomics study revealed intense expression of IL-1β and activation of profibrotic signals in the saline-treated hearts and their suppression in MSC exosome-treated hearts. To our knowledge, this is the first report on the infarct and peri-infarct area proteomics of ischemic mice hearts to explain MSC exosome-mediated suppression of scar formation in the ischemic mouse hearts.

Nanotechnology in cardiac stem cell therapy: cell modulation, imaging and gene delivery

The wide arena of applications opened by nanotechnology is multidimensional. It is already been proven that its prominence can continuously influence human life. The role of stem cells in curing degenerative diseases is another major area of research. Cardiovascular diseases are one of the major causes of death globally. Nanotechnology-assisted stem cell therapy could be used to tackle the challenges faced in the management of cardiovascular diseases. In spite of the positive indications and proven potential of stem cells to differentiate into cardiomyocytes for cardiac repair and regeneration during myocardial infarction, this therapeutic approach still remains in its infancy due to several factors such as non-specificity of injected cells, insignificant survival rate, and low cell retention. Attempts to improve stem cell therapy using nanoparticles have shown some interest among researchers. This review focuses on the major hurdles associated with cardiac stem cell therapy and the role of nanoparticles to overcome the major challenges in this field, including cell modulation, imaging, tracking and gene delivery.

This review summarizes the potential challenges present in cardiac stem cell therapy and the major role of nanotechnology to overcome these challenges including cell modulation, tracking and imaging of stem cells.

Platelet membrane and stem cell exosome hybrid enhances cellular uptake and targeting to heart injury

Exosomes from mesenchymal stem cells have been largely studied as therapeutics to treat myocardial infarctions. However, exosomes injected for therapeutic purposes face a number of challenges, including competition from exosomes already in circulation, and the internalization/clearance by the mononuclear phagocyte system. In this study, we hybrid exosomes with platelet membranes to enhance their ability to target the injured heart and avoid being captured by macrophages. Furthermore, we found that encapsulation by the platelet membranes induces macropinocytosis, enhancing the cellular uptake of exosomes by endothelial cells and cardiomyocytes strikingly. In vivo studies showed that the cardiac targeting ability of hybrid exosomes in a mice model with myocardial infarction injury. Last, we tested cardiac functions and performed immunohistochemistry to confirm a better therapeutic effect of platelet membrane modified exosomes compared to non-modified exosomes. Our studies provide proof-of-concept data and a universal approach to enhance the binding and accumulation of exosomes in injured tissues.

A Minimally Invasive Exosome Spray Repairs Heart after Myocardial Infarction

Myocardial infarction (MI) remains the most common cause of death worldwide. Many MI survivors will suffer from recurrent heart failure (HF), which has been recognized as a determinant of adverse prognosis. Despite the success of improved early survival after MI by primary percutaneous coronary intervention, HF after MI is becoming the major driver of late morbidity, mortality, and healthcare costs. The development of regenerative medicine has brought hope to MI treatment in the past decade. Mesenchymal stem cell (MSC)-derived exosomes have been established as an essential part of stem cell paracrine factors for heart regeneration. However, its regenerative power is hampered by low delivery efficiency to the heart. We designed, fabricated, and tested a minimally invasive exosome spray (EXOS) based on MSC exosomes and biomaterials. In a mouse model of acute myocardial infarction, EXOS improved cardiac function and reduced fibrosis, and promoted endogenous angiomyogenesis in the post-injury heart. We further tested the feasibility and safety of EXOS in a pig model. Our results indicate that EXOS is a promising strategy to deliver therapeutic exosomes for heart repair.

Improved Reactive Oxygen Species Generation by Chiral Co3 O4 Supraparticles under Electromagnetic Fields

One of the most common methods to treat thromboembolism is the use of thrombolytic drugs to activate fibrinolytic protease. The aim of this treatment was to initiate the lysis of fibrin; however, there are many side-effects associated with this form of treatment. Herein, we fabricated chiral Co₃ O₄ supraparticles (SPs) with a g-factor of up to 0.02 at 550 nm and paramagnetic performance applied in the treatment of thromboembolism under an electromagnetic field (MF). In vitro experiments showed that d-SPs degraded blood clot within 8 hours under MF. Compared to l-SPs, d-SPs exhibited much stronger thrombolytic ability and effectively enhanced the survival rate of thrombosis model mice more than 70 % in the 25 d of observation. The results of mechanism study showed that under MF, the level of reactive oxygen species (ROS) produced by d-SPs were 1.5 times higher than that of l-SPs, which might be attributed to the chiral-induced spin selectivity effects.

Nitrate-functionalized patch confers cardioprotection and improves heart repair after myocardial infarction via local nitric oxide delivery

Nitric oxide (NO) is a short-lived signaling molecule that plays a pivotal role in cardiovascular system. Organic nitrates represent a class of NO-donating drugs for treating coronary artery diseases, acting through the vasodilation of systemic vasculature that often leads to adverse effects. Herein, we design a nitrate-functionalized patch, wherein the nitrate pharmacological functional groups are covalently bound to biodegradable polymers, thus transforming small-molecule drugs into therapeutic biomaterials. When implanted onto the myocardium, the patch releases NO locally through a stepwise biotransformation, and NO generation is remarkably enhanced in infarcted myocardium because of the ischemic microenvironment, which gives rise to mitochondrial-targeted cardioprotection as well as enhanced cardiac repair. The therapeutic efficacy is further confirmed in a clinically relevant porcine model of myocardial infarction. All these results support the translational potential of this functional patch for treating ischemic heart disease by therapeutic mechanisms different from conventional organic nitrate drugs.

Biomimetic PLGA Microbubbles Coated with Platelet Membranes for Early Detection of Myocardial Ischaemia-Reperfusion Injury

Early diagnosis of myocardial ischaemia-reperfusion (MI/R) injury is important for protecting the myocardium and improving patient prognoses. Fortunately, the platelet membrane possesses the ability to target the region of MI/R injury. Therefore, we hypothesized that platelet membrane-coated particles (PMPs) could be used to detect early MI/R injury by ultrasound imaging. We designed PMPs with a porous polylactic-co-glycolic acid (PLGA) core coated with a platelet membrane shell. Red blood cell membrane-coated particles (RMPs) were fabricated as controls. Transmission electron microscopy (TEM) and fluorescence microscopy were applied to confirm the membrane coatings of the PMPs and RMPs. In vitro imaging of the PMPs and RMPs was verified. Moreover, binding experiments were designed to examine the targeting ability of the PMPs. Finally, we assessed the signal intensity of the adherent PMPs in the risk area and remote area by ultrasound imaging based on an MI/R rat model. The platelet membrane equipped the PMPs with an accurate targeting ability. Compared with RMPs, PMPs showed significantly more adhesion to human umbilical vein endothelial cells and collagen IV in vitro. Both PMPs and RMPs exhibited good enhancement ability in vitro and in vivo. Furthermore, the signal intensity of PMPs in the risk area was significantly higher than that in remote areas. These results were further validated by an immunofluorescence assay and ex vivo fluorescence imaging. In summary, ultrasound imaging with PMPs can detect early MI/R injury in a noninvasive manner.

Bioengineering Technologies for Cardiac Regenerative Medicine

Cardiac regenerative medicine faces big challenges such as a lack of adult cardiac stem cells, low turnover of mature cardiomyocytes, and difficulty in therapeutic delivery to the injured heart. The interaction of bioengineering and cardiac regenerative medicine offers innovative solutions to this field. For example, cell reprogramming technology has been applied by both direct and indirect routes to generate patient-specific cardiomyocytes. Various viral and non-viral vectors have been utilized for gene editing to intervene gene expression patterns during the cardiac remodeling process. Cell-derived protein factors, exosomes, and miRNAs have been isolated and delivered through engineered particles to overcome many innate limitations of live cell therapy. Protein decoration, antibody modification, and platelet membranes have been used for targeting and precision medicine. Cardiac patches have been used for transferring therapeutics with better retention and integration. Other technologies such as 3D printing and 3D culture have been used to create replaceable cardiac tissue. In this review, we discuss recent advancements in bioengineering and biotechnologies for cardiac regenerative medicine.

Cardiac fibrosis: Myofibroblast-mediated pathological regulation and drug delivery strategies

Cardiac fibrosis remains an unresolved problem in heart diseases. After initial injury, cardiac fibroblasts (CFs) are activated and subsequently differentiate into myofibroblasts (myoFbs) that are major mediator cells in the pathological remodeling. MyoFbs exhibit proliferative and secretive characteristics, and contribute to extracellular matrix (ECM) turnover, collagen deposition. The persistent functions of myoFbs lead to fibrotic scars and cardiac dysfunction. The anti-fibrotic treatment is hindered by the elusive mechanism of fibrosis and lack of specific targets on myoFbs. In this review, we will outline the progress of cardiac fibrosis and its contributions to the heart failure. We will also shed light on the role of myoFbs in the regulation of adverse remodeling. The communication between myoFbs and other cells that are involved in the heart injury and repair respectively will be reviewed in detail. Then, recently developed therapeutic strategies to treat fibrosis will be summarized such as i) chimeric antigen receptor T cell (CAR-T) therapy with an optimal target on myoFbs, ii) direct reprogramming from stem cells to quiescent CFs, iii) "off-target" small molecular drugs. The application of nano/micro technology will be discussed as well, which is involved in the construction of cell-based biomimic platforms and "pleiotropic" drug delivery systems.

Advances in 3D bioprinting technology for cardiac tissue engineering and regeneration

Cardiovascular disease is still one of the leading causes of death in the world, and heart transplantation is the current major treatment for end-stage cardiovascular diseases. However, because of the shortage of heart donors, new sources of cardiac regenerative medicine are greatly needed. The prominent development of tissue engineering using bioactive materials has creatively laid a direct promising foundation. Whereas, how to precisely pattern a cardiac structure with complete biological function still requires technological breakthroughs. Recently, the emerging three-dimensional (3D) bioprinting technology for tissue engineering has shown great advantages in generating micro-scale cardiac tissues, which has established its impressive potential as a novel foundation for cardiovascular regeneration. Whether 3D bioprinted hearts can replace traditional heart transplantation as a novel strategy for treating cardiovascular diseases in the future is a frontier issue. In this review article, we emphasize the current knowledge and future perspectives regarding available bioinks, bioprinting strategies and the latest outcome progress in cardiac 3D bioprinting to move this promising medical approach towards potential clinical implementation.

Bio-inspired nanomaterials as novel options for the treatment of cardiovascular disease

Cardiovascular disease (CVD) and its sequelae have long been the leading causes of death and disability in the developed world. Although mortality associated with CVD has been decreasing, due in large part to novel therapeutic options, the rate of decrease has flattened. Thus, there is a great need to investigate alternate therapeutic strategies that can increase efficacy while decreasing adverse effects. Nanomaterials have been widely investigated and have emerged as promising tools for both therapeutic and diagnostic purposes in oncology; however, the potential of nanomaterials has not been extensively explored for cardiovascular medicine. In this review, we focus on recent developments in the field of nanomedicines targeted for CVDs, with a special emphasis on cell membrane-coated nanoparticles (NPs) and their applications.

Stem cell-based therapies for cardiac diseases: The critical role of angiogenic exosomes

Finding effective treatments for cardiac diseases is among the hottest subjects in medicine; cell-based therapies have brought great promises for managing a broad range of life-threatening heart complications such as myocardial infarction. After clarifying the critical role of angiogenesis in tissue repair and regeneration, various stem/progenitor cell were utilized to accelerate the healing of injured cardiac tissue. Embryonic, fetal, adult, and induced pluripotent stem cells have shown the appropriate proangiogenic potential for tissue repair strategies. The capability of stem cells for differentiating into endothelial lineages was initially introduced as the primary mechanism involved in improving angiogenesis and accelerated heart tissue repair. However, recent studies have demonstrated the leading role of paracrine factors secreted by stem cells in advancing neo-vessel formation. Genetically modified stem cells are also being applied for promoting angiogenesis regarding their ability to considerably overexpress and secrete angiogenic bioactive molecules. Yet, conducting further research seems necessary to precisely identify molecular mechanisms behind the proangiogenic potential of stem cells, including the signaling pathways and regulatory molecules such as microRNAs. In conclusion, stem cells' pivotal roles in promoting angiogenesis and consequent improved cardiac healing and remodeling processes should not be ignored, especially in the case of stem cell-derived extracellular vesicles.