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Platelets are small anucleated blood cells primarily known for their vital hemostatic role. Allogeneic platelet concentrates (PCs) collected from healthy donors are an essential cellular product transfused by hospitals to control or prevent bleeding in patients affected by thrombocytopenia or platelet dysfunctions. Platelets fulfill additional essential functions in innate and adaptive immunity and inflammation, as well as in wound-healing and tissue-repair mechanisms. Platelets contain mitochondria, lysosomes, dense granules, and alpha-granules, which collectively are a remarkable reservoir of multiple trophic factors, enzymes, and signaling molecules. In addition, platelets are prone to release in the blood circulation a unique set of extracellular vesicles (p-EVs), which carry a rich biomolecular cargo influential in cell–cell communications. The exceptional functional roles played by platelets and p-EVs explain the recent interest in exploring the use of allogeneic PCs as source material to develop new biotherapies that could address needs in cell therapy, regenerative medicine, and targeted drug delivery. Pooled human platelet lysates (HPLs) can be produced from allogeneic PCs that have reached their expiration date and are no longer suitable for transfusion but remain valuable source materials for other applications. These HPLs can substitute for fetal bovine serum as a clinical grade xeno-free supplement of growth media used in the in vitro expansion of human cells for transplantation purposes. The use of expired allogeneic platelet concentrates has opened the way for small-pool or large-pool allogeneic HPLs and HPL-derived p-EVs as biotherapy for ocular surface disorders, wound care and, potentially, neurodegenerative diseases, osteoarthritis, and others. Additionally, allogeneic platelets are now seen as a readily available source of cells and EVs that can be exploited for targeted drug delivery vehicles. This article aims to offer an in-depth update on emerging translational applications of allogeneic platelet biotherapies while also highlighting their advantages and limitations as a clinical modality in regenerative medicine and cell therapies.

Extracellular vesicles (EVs) hold significant promise as biomarkers and therapeutics, yet their isolation remains challenging due to their low abundance and complex sample matrices. Here, we introduce EV-Osmoprocessor (EVOs), a novel device that leverages osmosis-driven filtration for rapid and efficient EV isolation. EVOs employs a high osmolarity polymer solution to concentrate EVs while simultaneously removing smaller contaminants. Compared to traditional methods such as ultracentrifugation and precipitation, EVOs offers speed and convenience, achieving a 50-fold volume reduction in under 2 h. Our results show that EVOs retained EVs and removed >99% albumin from the cell conditioned culture medium (CCM). The isolated EVs exhibited a particle size distribution centered around 140 nm, which was very similar to EVs isolated via precipitation or ultracentrifugation. The standalone EVOs process achieved a particle:protein ratio (EV purity) of ~10 particles/µg protein. Comprehensive characterization, including cryo-electron microscopy, validation of protein markers and known miRNA cargo confirmed the successful isolation of EVs. Functional assays, based on protection of cardiomyocytes from hypoxia/reoxygenation injury, demonstrated the bioactivity of EVOs-isolated EVs. Furthermore, we show that EVOs can be used to concentrate 30 ml of CCM into a 0.5 ml solution, which was then further processed with size-exclusion chromatography (SEC), improving EV purity to ~10 particles/µg protein. This work establishes EVOs as a promising tool for EV research and clinical applications, offering a streamlined approach to EV isolation with enhanced analytical performance.

Nanoparticles represent an attractive option for systemic delivery of therapeutic compounds to the heart following myocardial infarction. However, it is well known that physicochemical properties of nanoparticles such as size, shape and surface modifications can vastly alter the distribution and uptake of injected nanoparticles. Therefore, we aimed to provide an examination of the rapid size-dependent uptake of fluorescent PEG-modified polystyrene nanoparticles administered immediately following cardiac ischaemia-reperfusion injury in mice. By assessing the biodistribution of nanoparticles with core diameters between 20 nm and 2 μm 30 minutes after their administration, we conclude that 20–200 nm diameter nanoparticles are optimal for passive targeting of the injured left ventricle.

The severe acute respiratory syndrome coronavirus (SARS-CoV)-2 disease (COVID)-19 is having profound effects on the global economy and food trade. Limited data are available on how this pandemic is affecting our dietary and lifestyle-related behaviors at the global level. Google Trends was used to obtain worldwide relative search volumes (RSVs) covering a timeframe from before the COVID-19 pandemic 1 June 2019 to 27 April 2020. Spearman’s rank-order correlation coefficients were used to measure relationships between daily confirmed cases and aforementioned RSVs between 31 December 2019 and 15 April 2020. RSV curves showed increased interest in multiple keywords related to dietary and lifestyle behaviors during the COVID-19 lockdown period in March and April 2020. Spearman’s correlation analysis showed that the strongest variables in each keyword category were (1) food security (food shortage: r = 0.749, food bank: r = 0.660, and free food: r = 0.555; all p < 0.001), (2) dietary behaviors (delivery: r = 0.780, restaurant: r = −0.731, take-away: r = 0.731, and food-delivery: r = 0.693; all p < 0.001), (3) outdoor-related behaviors (resort: r = −0.922, hotel: r = −0.913, cinema: r = −0.844, park: r = −0.827, fitness: r = −0.817, gym: r = −0.811; plant: r = 0.749, sunbathing: r = 0.668, and online: r = 0.670; all p < 0.001), and (4) immune-related nutrients/herbs/foods (vitamin C: r = 0.802, vitamin A: r = 0.780, zinc: r = 0.781, immune: r = 0.739, vitamin E: r = 0.707, garlic: r = 0.667, omega-3 fatty acid: r = −0.633, vitamin D: r = 0.549, and turmeric: r = 0.545; all p < 0.001). Restricted movement has affected peoples’ dietary and lifestyle behaviors as people tend to search for immune-boosting nutrients/herbs and have replaced outdoor activities with sedentary indoor behaviors.

Treatment of brain tumors is challenging since the blood–brain tumor barrier prevents chemotherapy drugs from reaching the tumor site in sufficient concentrations. Nanomedicines have great potential for therapy of brain disorders but are still uncommon in clinical use despite decades of research and development. Here, we provide an update on nano-carrier strategies for improving brain drug delivery for treatment of brain tumors, focusing on liposomes, extracellular vesicles and biomimetic strategies as the most clinically feasible strategies. Finally, we describe the obstacles in translation of these technologies including pre-clinical models, analytical methods and regulatory issues.

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.

Background Cell therapy can protect cardiomyocytes from hypoxia, primarily via paracrine secretions, including extracellular vesicles (EVs). Since EVs fulfil specific biological functions based on their cellular origin, we hypothesised that EVs from human cardiac stromal cells (CMSCLCs) obtained from coronary artery bypass surgery may have cardioprotective properties. Objectives This study characterises CMSCLC EVs (C_EVs), miRNA cargo, cardioprotective efficacy and transcriptomic modulation of hypoxic human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). C_EVs are compared to bone marrow mesenchymal stromal cell EVs (B_EVs) which are a known therapeutic EV type. Methods Cells were characterised for surface markers, gene expression and differentiation potential. EVs were compared for yield, phenotype, and ability to protect hiPSC-CMs from hypoxia/reoxygenation injury. EV dose was normalised by both protein concentration and particle count, allowing direct comparison. C_EV and B_EV miRNA cargo was profiled and RNA-seq was performed on EV-treated hypoxic hiPSC-CMs, then data were integrated by multi-omics. Confirmatory experiments were carried out using miRNA mimics. Results At the same dose, C_EVs were more effective than B_EVs at protecting CM integrity, reducing apoptotic markers, and cell death during hypoxia. While C_EVs and B_EVs shared 70–77% similarity in miRNA content, C_EVs contained unique miRNAs, including miR-202-5p, miR-451a and miR-142-3p. Delivering miRNA mimics confirmed that miR-1260a and miR-202/451a/142 were cardioprotective, and the latter upregulated protective pathways similar to whole C_EVs. Conclusions This study demonstrates the potential of cardiac tissues, routinely discarded following surgery, as a valuable source of EVs for myocardial infarction therapy. We also identify miR-1260a as protective of CM hypoxia.

Background Previous research has indicated that extracellular vesicles (EVs) potentially play significant roles in multiple ageing phenotypes. This study uses a factorial experimental design to explore the interactions between circulating EVs and bone marrow-derived macrophages (BMDMs) isolated from young (7–12 weeks) and aged (70–90 weeks) mice. Results In this study, plasma EVs from young (Y_EV) and aged (O_EV) mice were isolated and compared based on abundance, size, and miRNA cargo. Compared to some previous studies, we found relatively few differences in EV miRNA cargo between Y_EVs and O_EVs. Young and old EVs were then used to stimulate naïve BMDMs isolated from young (Y_BMDM) and aged (O_BMDM) mice. A panel of five “M1” and six “M2” macrophage markers were used to assess the degree of polarisation. Our results revealed differences in the immunomodulatory effects of Y_EVs and O_EVs in Y_BMDMs and O_BMDMs. Y_EVs induced less pro-inflammatory gene expression, while O_EVs exhibited a more varied impact, promoting both pro- and anti-inflammatory markers. However, neither EV population induced a clearly defined ‘M1’ or ‘M2’ macrophage phenotype. We also report that EVs elicited responses that differed markedly from those induced by whole plasma. Plasma from old mice had strong pro-inflammatory effects on Y_BMDMs, increasing Il1b , Nlrp3 and Tnfa . However, O_EVs did not have these effects, supporting current evidence that EVs are a separate component of circulating factors during ageing. More research is needed to elucidate specific factors involved in inflammageing processes. Conclusions Our findings reveal age-related differences in EV cargo and function, with young EVs tending to suppress inflammatory markers more effectively than aged EVs. However, this is not straightforward, and EVs often promoted both M1 and M2 markers. These results suggest that EVs are a distinct component of circulating factors and hold potential for therapeutic strategies aimed at mitigating age-related inflammation and immune dysregulation.

Although remnant cardiomyocytes (CMs) possess a certain degree of proliferative ability, efficiency is too low for cardiac regeneration after injury. In this study, we identified a distinct stage within the initiation phase of CM reprogramming before the MET process, and microarray analysis revealed the strong up‐regulation of several mitosis‐related genes at this stage of reprogramming. Several candidate genes were selected and tested for their ability to induce CM proliferation. Delivering a cocktail of three genes, FoxM1, Id1, and Jnk3‐shRNA (FIJs), induced CMs to re‐enter the cell cycle and complete mitosis and cytokinesis in vitro . More importantly, this gene cocktail increased CM proliferation in vivo and significantly improved cardiac function and reduced fibrosis after myocardial infarction. Collectively, our findings present a cocktail FIJs that may be useful in cardiac regeneration and also provide a practical strategy for probing reprogramming assays for regeneration of other tissues. Synopsis The proliferation rate of remnant cardiomyocytes (CMs) is too low for cardiac regeneration after injury. Here, a gene cocktail is defined to induce CMs to efficiently proliferate, while improving cardiac function after myocardial infarction in mice. The second day prior to the mesenchymal–epithelial transition was identified as the critical time for initiating cardiomyocyte reprogramming. Microarray data analysis pinpointed a set of up‐regulated genes that were used to derive a reprogramming gene cocktail. The gene cocktail recipe comprising FoxM1, Id1, and Jnk3‐shRNAs (FIJs) enhances cardiomyocyte proliferation. Cardiomyocyte cell cycle re‐entry is followed by completed mitosis and cytokinesis to execute a delayed reprogramming. The FIJs gene cocktail improves heart function after myocardial infarction in a mouse model. Graphical Abstract The proliferation rate of remnant cardiomyocytes (CMs) is too low for cardiac regeneration after injury. Here, a gene cocktail is defined to induce CMs to efficiently proliferate, while improving cardiac function after myocardial infarction in mice.

There is significant interest in the role of stem cells in cardiac regeneration, and yet little is known about how cardiac disease progression affects native cardiac stem cells in the human heart. In this brief report, cardiac mesenchymal stem cell-like cells (CMSCLC) from the right atria of a 21-year-old female patient with a bicuspid aortic valve and aortic stenosis (referred to as biscuspid aortic valve disease BAVD-CMSCLC), were compared with those of a 78-year-old female patient undergoing coronary artery bypass surgery (referred to as coronary artery disease CAD-CMSCLC). Cells were analyzed for expression of MSC markers, ability to form CFU-Fs, metabolic activity, cell cycle kinetics, expression of NANOG and p16, and telomere length. The cardiac-derived cells expressed MSC markers and were able to form CFU-Fs, with higher rate of formation in CAD-CMSCLCs. BAVD-CMSCLCs did not display normal MSC morphology, had a much lower cell doubling rate, and were less metabolically active than CAD-CMSCLCs. Cell cycle analysis revealed a population of BAVD-CMSCLC in G2/M phase, whereas the bulk of CAD-CMSCLC were in the G0/G1 phase. BAVD-CMSCLC had lower expression of NANOG and shorter telomere lengths, but higher expression of p16 compared with the CAD-CMSCLC. In conclusion, BAVD-CMSCLC have a prematurely aged phenotype compared with CAD-CMSCLC, despite originating from a younger patient.