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

Ischemia/Reperfusion Injury Enhances Accumulation of Perfluoropropane Droplets

OBJECTIVE

Perfluoropropane droplets (PD) are nanometer-sized particles that can be formulated from commercially available contrast agents. The preferential retention of PDs in diseased microvascular beds can be detected by ultrasound imaging techniques after acoustic activation and offers an opportunity for the detection of such processes as scar formation or inflammation. We hypothesized that in the presence of ischemia/reperfusion (I/R) injury, retention of intravenously injected PDs would be enhanced.

METHODS

Using an established intravital microscopy model of rat cremaster microcirculation, we determined the retention and subsequent acoustic activation behavior of PDs in exteriorized rat cremaster tissue. DiI-labeled droplets (200 µL) were administered intravenously. Acoustic activation was achieved with a clinical ultrasound system at two ultrasound frequencies (1.5 and 7 MHz).

RESULTS

Fluorescent microbubbles could be detected in the microvasculature after intravenous injection of PDs and subsequent acoustic activation. Increased retention of PDs was observed in the I/R group compared with control group with both ultrasound frequencies (p < 0.05). Using higher-resolution microscopy, we found evidence that some droplets extravasate to the outside of the endothelial border or are potentially engulfed by leukocytes.

CONCLUSION

Our data indicate that targeted imaging of the developing scar zones might be possible with ultrasound activation of intravenously injected PDs, and a method of targeting therapies to these same regions could be developed.

Platelet-mimicking nanoparticles loaded with diallyl trisulfide for Mitigating Myocardial Ischemia-Reperfusion Injury in rats

Hydrogen sulfide (H2S) shows promise in treating myocardial ischemia-reperfusion injury (MIRI), but the challenge of controlled and sustained release hinders its clinical utility. In this study, we developed a platelet membrane-encapsulated mesoporous silica nanoparticle loaded with the H2S donor diallyl trisulfide (PM-MSN-DATS). PM-MSN-DATS demonstrated optimal encapsulation efficiency and drug-loading content. Comprehensive in vitro and in vivo assessments confirmed the biosafety of PM-MSN-DATS. In vitro, PM-MSN-DATS adhered to inflammation-activated endothelial cells and exhibited targeted accumulation in MIRI rat hearts. In vivo experiments revealed significant reductions in reactive oxygen species (ROS) and myocardial fibrosis area, improving cardiac function. Our findings highlight successfully creating a targeted H2S delivery system through platelet membrane-coated MSN nanoparticles. This well-designed drug delivery platform holds significant promise for advancing MIRI treatment strategies.

Biomembrane-Modified Biomimetic Nanodrug Delivery Systems: Frontier Platforms for Cardiovascular Disease Treatment

Cardiovascular diseases (CVDs) are one of the leading causes of death worldwide. Despite significant advances in current drug therapies, issues such as poor drug targeting and severe side effects persist. In recent years, nanomedicine has been extensively applied in the research and treatment of CVDs. Among these, biomembrane-modified biomimetic nanodrug delivery systems (BNDSs) have emerged as a research focus due to their unique biocompatibility and efficient drug delivery capabilities. By modifying with biological membranes, BNDSs can effectively reduce recognition and clearance by the immune system, enhance biocompatibility and circulation time in vivo, and improve drug targeting. This review first provides an overview of the classification and pathological mechanisms of CVDs, then systematically summarizes the research progress of BNDSs in the treatment of CVDs, discussing their design principles, functional characteristics, and clinical application potential. Finally, it highlights the issues and challenges faced in the clinical translation of BNDSs.

Advances in Engineered Nanoparticles for the Treatment of Ischemic Stroke by Enhancing Angiogenesis

Angiogenesis, or the formation of new blood vessels, is a natural defensive mechanism that aids in the restoration of oxygen and nutrition delivery to injured brain tissue after an ischemic stroke. Angiogenesis, by increasing vessel development, may maintain brain perfusion, enabling neuronal survival, brain plasticity, and neurologic recovery. Induction of angiogenesis and the formation of new vessels aid in neurorepair processes such as neurogenesis and synaptogenesis. Advanced nano drug delivery systems hold promise for treatment stroke by facilitating efficient transportation across the the blood-brain barrier and maintaining optimal drug concentrations. Nanoparticle has recently been shown to greatly boost angiogenesis and decrease vascular permeability, as well as improve neuroplasticity and neurological recovery after ischemic stroke. We describe current breakthroughs in the development of nanoparticle-based treatments for better angiogenesis therapy for ischemic stroke employing polymeric nanoparticles, liposomes, inorganic nanoparticles, and biomimetic nanoparticles in this study. We outline new nanoparticles in detail, review the hurdles and strategies for conveying nanoparticle to lesions, and demonstrate the most recent advances in nanoparticle in angiogenesis for stroke treatment.

Platelet membrane-derived biomimetic microbubbles with enhanced targeting ability for the early detection of myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a widely recognized cardiovascular disease that significantly impacts the prognosis of patients undergoing myocardial infarction recanalization. This condition can be fatal and involves complex pathophysiological mechanisms. Early diagnosis of MIRI is crucial to minimize myocardial damage and reducing mortality. Based on the inherent relationship between platelets and MIRI, we developed biomimetic microbubbles coated with platelet membrane (MB-pla) for early identification of MIRI. The MB-pla were prepared through a recombination process involving platelet membrane obtained from rat whole blood and phospholipids, blended in appropriate proportions. By coating the microbubbles with platelet membrane, MB-pla acquired various adhesion molecules, thereby gaining the capability to selectively adhere to damaged endothelial cells in the context of MIRI. In vitro experiments demonstrated that MB-pla exhibited remarkable targeting characteristics, particularly toward type IV collagen and human umbilical vein endothelial cells that had been injured through hypoxia/reoxygenation procedures. In a rat model of MIRI, the signal intensity produced by MB-pla was notably higher than that of control microbubbles. These findings were consistent with results obtained from fluorescence imaging of isolated hearts and immunofluorescence staining of tissue sections. In conclusion, MB-pla has great potential as a non-invasive early detection method for MIRI. Furthermore, this approach can potentially find application in other conditions involving endothelial injury in the future.

Platelet membrane-coated bio-nanoparticles of indocyanine green/elamipretide for NIR diagnosis and antioxidant therapy in acute kidney injury

Acute kidney injury (AKI) is a prevalent condition in critically ill patients that is often associated with significant morbidity and mortality. As the lack of effective early diagnosis methods often delays AKI treatment, there is currently no definitive clinical intervention available. In this study, we aimed to address these challenges by developing a nano-system called Platelet membranes-ICG-SS31-PLGA (PISP), which was designed to selectively target to the kidney site, taking advantage of the natural tendency of platelets to accumulate at sites of vascular injury. This approach allowed for the accumulation of PISP within the kidney as the disease progresses. By incorporating ICG, the in vivo distribution of PISP can be observed for NIR diagnosis of AKI. This non-invasive imaging technique holds great promise for early detection and monitoring of AKI. Furthermore, Elamipretide (SS31) acts as a mitochondria-targeted antioxidant that protects against mitochondrial damage and reduces oxidative stress, inflammation, and apoptosis. The combination of diagnostic and therapeutic capabilities within a single nano-system makes the PISP approach a valuable tool for addressing AKI. This intervention helps to prevent the deterioration of AKI and promotes the recovery. STATEMENT OF SIGNIFICANCE.

Polymeric materials for ultrasound imaging and therapy

Ultrasound (US) is routinely used for diagnostic imaging and increasingly employed for therapeutic applications. Materials that act as cavitation nuclei can improve the resolution of US imaging, and facilitate therapeutic US procedures by promoting local drug delivery or allowing temporary biological barrier opening at moderate acoustic powers. Polymeric materials offer a high degree of control over physicochemical features concerning responsiveness to US, e.g. via tuning chain composition, length and rigidity. This level of control cannot be achieved by materials made of lipids or proteins. In this perspective, we present key engineered polymeric materials that respond to US, including microbubbles, gas-stabilizing nanocups, microcapsules and gas-releasing nanoparticles, and discuss their formulation aspects as well as their principles of US responsiveness. Focusing on microbubbles as the most common US-responsive polymeric materials, we further evaluate the available chemical toolbox to engineer polymer shell properties and enhance their performance in US imaging and US-mediated drug delivery. Additionally, we summarize emerging applications of polymeric microbubbles in molecular imaging, sonopermeation, and gas and drug delivery, based on refinement of MB shell properties. Altogether, this manuscript provides new perspectives on US-responsive polymeric designs, envisaging their current and future applications in US imaging and therapy.

What do we know about platelets in myocardial ischemia-reperfusion injury and why is it important?

Myocardial ischemia-reperfusion injury (MIRI), the joint result of ischemic injury and reperfusion injury, is associated with poor outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention. Accumulating evidence demonstrates that activated platelets directly contribute to the pathogenesis of MIRI through participating in the formation of microthrombi, interaction with leukocytes, secretion of active substances, constriction of microvasculature, and activation of spinal afferent nerves. The molecular mechanisms underlying the above detrimental effects of activated platelets include the homotypic and heterotypic interactions through surface receptors, transduction of intracellular signals, and secretion of active substances. Revealing the roles of platelet activation in MIRI and the associated mechanisms would provide potential targets/strategies for the clinical evaluation and treatment of MIRI. Further studies are needed to characterize the temporal (ischemia phase vs. reperfusion phase) and spatial (systemic vs. local) distributions of platelet activation in MIRI by multi-omics strategies. To improve the likelihood of translating novel cardioprotective interventions into clinical practice, basic researches maximally replicating the complexity of clinical scenarios would be necessary.

Biomimetic Nanoparticles Loaded with Ulinastatin for the Targeted Treatment of Acute Pancreatitis

Ulinastatin is commonly used in the clinic to treat acute pancreatitis (AP), but its therapeutic effect was limited by the presence of the blood-pancreas barrier (BPB) and low specificity. Here, we prepared a macrophage biomimetic nanoparticle (MU) that delivered ulinastatin to address the above issues. Macrophage membrane was used as a shell for a mixture of PEG-PLGA and ulinastatin. It was found that MU showed good stability and biocompatibility in vitro and in vivo. According to in vivo fluorescence imaging, MU displayed a great inflammation targeting effect both in a subcutaneous inflammation model and in situ pancreatitis mouse model, which was ascribed to the presence of adhesion proteins. In vitro and in vivo results demonstrated that MU have a superior AP treatment effect by inhibiting pro-inflammatory factors and keeping cells viability. It was suggested the MU could provide a new strategy for targeted AP treatment.

Dual-modal molecular imaging and therapeutic evaluation of coronary microvascular dysfunction using indocyanine green-doped targeted microbubbles

Coronary microvascular dysfunction (CMD), which causes a series of cardiovascular diseases, seriously endangers human health. However, precision diagnosis of CMD is still challenging due to the lack of sensitive probes and complementary imaging technologies. Herein, we demonstrate indocyanine green-doped targeted microbubbles (named T-MBs-ICG) as dual-modal probes for highly sensitive near-infrared (NIR) fluorescence imaging and high-resolution ultrasound imaging of CMD in mouse models. In vitro results show that T-MBs-ICG can specifically target fibrin, a specific CMD biomarker, via the cysteine-arginine-glutamate-lysine-alanine (CREKA) peptide modified on the surface of microbubbles. We further employ T-MBs-ICG to achieve NIR fluorescence imaging of injured myocardial tissue in a CMD mouse model, leading to a signal-to-background ratio (SBR) of up to 50, which is 20 fold higher than that of the non-targeted group. Furthermore, ultrasound molecular imaging of T-MBs-ICG is obtained within 60 s after intravenous injection, providing molecular information on ventricular and myocardial structures and fibrin with a resolution of 1.033 mm × 0.466 mm. More importantly, we utilize comprehensive dual-modal imaging of T-MBs-ICG to evaluate the therapeutic efficacy of rosuvastatin, a cardiovascular drug for the clinical treatment of CMD. Overall, the developed T-MBs-ICG probes with good biocompatibility exhibit great potential in the clinical diagnosis of CMD.

Biomimetic cell membrane-coated poly(lactic-co-glycolic acid) nanoparticles for biomedical applications

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are commonly used for drug delivery because of their favored biocompatibility and suitability for sustained and controlled drug release. To prolong NP circulation time, enable target-specific drug delivery and overcome physiological barriers, NPs camouflaged in cell membranes have been developed and evaluated to improve drug delivery. Here, we discuss recent advances in cell membrane-coated PLGA NPs, their preparation methods, and their application to cancer therapy, management of inflammation, treatment of cardiovascular disease and control of infection. We address the current challenges and highlight future research directions needed for effective use of cell membrane-camouflaged NPs.

Platelet Internalization Mediates Ferroptosis in Myocardial Infarction

BACKGROUND

Myocardial cell death is the hallmark of myocardial infarction. In the process of myocardial injury, platelets contribute to the pathogenesis by triggering intense inflammatory responses. Yet, it is still unclear if platelets regulate cardiomyocyte death directly, thereby exacerbating myocardial injury in myocardial infarction.

METHODS

We describe a mechanism underlying the correlative association between platelets accumulation and myocardial cell death by using myocardial infarction mouse model and patient specimens.

RESULTS

Myocardial infarction induces platelets internalization, resulting in the release of miR-223-3p, a platelet-enriched miRNA. By targeting the ACSL3, miR-223-3p delivered by internalized platelets cause the reduction of stearic acid-phosphatidylcholine in cardiomyocytes. The presence of stearic acid-phosphatidylcholine protects cardiomyocytes against ferroptosis.

CONCLUSIONS

Our work reveals a novel mechanism of platelet-mediated myocardial injury, highlighting antiplatelet therapies could potentially represent a multimechanism treatment of myocardial infarction, and implying ferroptosis being considered as novel target for therapeutics.

Berberin sustained-release nanoparticles were enriched in infarcted rat myocardium and resolved inflammation

Inflammatory regulation induced by macrophage polarization is essential for cardiac repair after myocardial infarction (MI). Berberin (BBR) is an isoquinoline tetrasystemic alkaloid extracted from plants. This study analyzes the most likely mechanism of BBR in MI treatment determined via network pharmacology, showing that BBR acts mainly through inflammatory responses. Because platelets (PLTs) can be enriched in the infarcted myocardium, PLT membrane-coated polylactic-co-glycolic acid (PLGA) nanoparticles (BBR@PLGA@PLT NPs) are used, which show enrichment in the infarcted myocardium to deliver BBR sustainably. Compared with PLGA nanoparticles, BBR@PLGA@PLT NPs are more enriched in the infarcted myocardium and exhibit less uptake in the liver. On day three after MI, BBR@PLGA@PLT NPs administration significantly increases the number of repaired macrophages and decreases the number of inflammatory macrophages and apoptotic cells in infarcted rat myocardium. On the 28th day after MI, the BBR@PLGA@PLT group exhibits a protective effect on cardiac function, reduced cardiac collagen deposition, improved scar tissue stiffness, and an excellent angiogenesis effect. In addition, BBR@PLGA@PLT group has no significant impact on major organs either histologically or enzymologically. In summary, the therapeutic effect of BBR@PLGA@PLT NPs on MI is presented in detail from the perspective of the resolution of inflammation, and a new solution for MI treatment is proposed.

Cell membrane-camouflaged PLGA biomimetic system for diverse biomedical application

The emerging cell membrane (CM)-camouflaged poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) (CM@PLGA NPs) have witnessed tremendous developments since coming to the limelight. Donning a novel membrane coat on traditional PLGA carriers enables combining the strengths of PLGA with cell-like behavior, including inherently interacting with the surrounding environment. Thereby, the in vivo defects of PLGA (such as drug leakage and poor specific distribution) can be overcome, its therapeutic potential can be amplified, and additional novel functions beyond drug delivery can be conferred. To elucidate the development and promote the clinical transformation of CM@PLGA NPs, the commonly used anucleate and eukaryotic CMs have been described first. Then, CM engineering strategies, such as genetic and nongenetic engineering methods and hybrid membrane technology, have been discussed. The reviewed CM engineering technologies are expected to enrich the functions of CM@PLGA for diverse therapeutic purposes. Third, this article highlights the therapeutic and diagnostic applications and action mechanisms of PLGA biomimetic systems for cancer, cardiovascular diseases, virus infection, and eye diseases. Finally, future expectations and challenges are spotlighted in the concept of translational medicine.

Targeted delivery of fat extract by platelet membrane-cloaked nanocarriers for the treatment of ischemic stroke

BACKGROUND

Our previous studies suggest that human fat extract (FE) contains a variety of angiogenic factors and may provide an alternative treatment option for stroke. However, the therapeutic effect is largely limited due to its short half-life, and inaccurate targeting.

RESULTS

Herein, we leverage the targeting abilities of platelets (PLTs) to the lesion area of stroke and Arg-Gly-Asp (RGD) peptides to the angiogenic blood vessels to develop a biomimetic nanocarrier that capable of delivering FE precisely to treat stroke. The biomimetic nanocarriers are comprised of FE-encapsulated PLGA (poly(lactic-co-glycolic acid)) core enclosed by RGD peptides decorated plasma membrane of PLTs, namely RGD-PLT@PLGA-FE. We found that RGD-PLT@PLGA-FE not only targeted damaged and inflamed blood vessels but also achieved rapid accumulation in the lesion area of ischemic brain. In addition, RGD-PLT@PLGA-FE kept a sustained release behavior of FE at the lesion site, effectively increased its half-life and promoted angiogenesis and neurogenesis with delivering neurotrophic factors including BDNF, GDNF and bFGF to the brain, that ultimately resulted in blood flow increase and neurobehavioral recovery.

CONCLUSIONS

In conclusion, our study provides a new strategy to design a biomimetic system for FE delivery and it is a promising modality for stroke therapy.

Research Progress of Imaging Methods for Detection of Microvascular Angina Pectoris in Diabetic Patients

Diabetes is a complex metabolic disease characterized by hyperglycemia. Its complications are various, often involving the heart, brain, kidney, and other essential organs. At present, the number of diabetic patients in the world is growing day by day. The cardiovascular disease caused by diabetes has dramatically affected the quality of life of diabetic patients. It is the leading cause of death of diabetic patients. Diabetic patients often suffer from microvascular angina pectoris without obstructive coronary artery disease. Still, there are typical ECG ischemia and angina pectoris, that is, chest pain and dyspnea under exercise. Unlike obstructive coronary diseases, nitrate does not affect chest pain caused by coronary microvascular angina in most cases. With the increasing emphasis on diabetic microvascular angina, the need for accurate diagnosis of the disease is also increasing. We can use SPECT, PET, CMR, MCE, and other methods to evaluate coronary microvascular function. SPECT is commonly used in clinical practice, and PET is considered the gold standard for non-invasive detection of myocardial blood flow. This article mainly introduces the research progress of these imaging methods in detecting microvascular angina in diabetic patients.