Raman Fingerprint of Extracellular Vesicles and Conditioned Media for the Reproducibility Assessment of Cell-Free Therapeutics

Mesenchymal stem cell-derived cell-free technologies: a patent landscape

Mesenchymal stem/stromal cells (MSC) play a pivotal role in regenerative therapies. Recent studies show that factors secreted by MSC can replicate their biological activity, driving the emergence of cell-free therapy, likely to surpass stem cell therapy. Patents are an objective measure of R&D and innovation activities, and patent mapping allows us to verify the state of the art and technology, anticipate trends, and identify emerging lines of research. This review performed a search on Derwent World Patents Index™ and retrieved 269 patent families related to the MSC-derived cell-free products. Analysis reveals an exponential increase in patents from the mid-2010s, primarily focusing on exosomes. The patent's contents offer a great diversity of applications and associated technologies by using the products as medicinal agents or drug delivery systems. Nevertheless, numerous application branches remain unexplored, suggesting vast potential for cell-free technologies alone or combined with other approaches.

Toward the nanoscale chemical and physical probing of milk-derived extracellular vesicles using Raman and tip-enhanced Raman spectroscopy

Tip-enhanced Raman spectroscopy (TERS) is an advanced technique to perform local chemical analysis of the surface of a sample through the improvement of the sensitivity and the spatial resolution of Raman spectroscopy by plasmonic enhancement of the electromagnetic signal in correspondence with the nanometer-sized tip of an atomic force microscope (AFM). In this work, TERS is demonstrated to represent an innovative and powerful approach for studying extracellular vesicles, in particular bovine milk-derived extracellular vesicles (mEVs), which are nanostructures with considerable potential in drug delivery and therapeutic applications. Raman spectroscopy has been used to analyze mEVs at the micrometric and sub-micrometric scales to obtain a detailed Raman spectrum in order to identify the 'signature' of mEVs in terms of their characteristic molecular vibrations and, therefore, their chemical compositions. With the ability to improve lateral resolution, TERS has been used to study individual mEVs, demonstrating the possibility of investigating a single mEV selected on the surface of the sample and, moreover, analyzing specific locations on the selected mEV with nanometer lateral resolution. TERS potentially allows one to reveal local differences in the composition of mEVs providing new insights into their structure. Also, thanks to the intrinsic properties of TERS to acquire the signal from only the first few nanometers of the surface, chemical investigation of the lipid membrane in correspondence with the various locations of the selected mEV could be performed by analyzing the peaks of the Raman shift in the relevant range of the spectrum (2800-3000 cm-1). Despite being limited to mEVs, this work demonstrates the potential of TERS in the analysis of extracellular vesicles.

A roadmap towards manufacturing extracellular vesicles for cardiac repair

For the past two decades researchers have linked extracellular vesicle (EV)-mediated mechanisms to various physiological and pathological processes in the heart, such as immune response regulation, fibrosis, angiogenesis, and the survival and growth of cardiomyocytes. Although use of EVs has gathered momentum in the cardiac field, several obstacles in both upstream and downstream processes during EV manufacture need to be addressed before clinical success can be achieved. Low EV yields obtained in small-scale cultures deter clinical translation, as mass production is a prerequisite to meet therapeutic doses. Moreover, standardizing EV manufacture is critical given the inherent heterogeneity of EVs and the constraints of current isolation techniques. In this review, we discuss the critical steps for the large-scale manufacturing of high-potency EVs for cardiac therapies.

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.

Boosting the therapeutic potential of cell secretome against osteoarthritis: Comparison of cytokine-based priming strategies

The secretome, or conditioned medium (CM), from Mesenchymal Stem/stromal Cells (MSCs) has recently emerged as a promising cell-free therapeutic against osteoarthritis (OA), capable of promoting cartilage regeneration and immunoregulation. Priming MSCs with 10 ng/ml tumor necrosis factor α (TNFα) and/or 10 ng/ml interleukin 1β (IL-1β) aims at mimicking the pathological milieu of OA joints in order to target their secretion towards a pathology-tailored phenotype. Here we compare the composition of the CM obtained after 24 or 72 h from untreated and cytokine-treated adipose-derived MSCs (ASCs). The 72-hour double-primed CM presents a higher total protein yield, a larger number of extracellular vesicles, and a greater concentration of bioactive lipids, in particular sphingolipids, fatty acids, and eicosanoids. Moreover, the levels of several factors involved in immunomodulation and regeneration, such as TGF-β1, PGE2, and CCL-2, are strongly upregulated. Additionally, the differential profiling of 80 bioactive molecules indicates that primed CM is enriched in immune cell chemotaxis and migration factors. Our results indicate that pre-conditioning ASCs with inflammatory cytokines can modulate the composition of their CM, promoting the release of factors with recognized anti-inflammatory, chondroprotective, and immunoregulatory properties.

The Utilization of Plant-Material-Loaded Vesicular Drug Delivery Systems in the Management of Pulmonary Diseases

Medicinal plants have been utilized to treat a variety of conditions on account of the bioactive properties that they contain. Most bioactive constituents from plants are of limited effectiveness, due to poor solubility, limited permeability, first-pass metabolism, efflux transporters, chemical instability, and food-drug interactions However, when combined with vesicular drug delivery systems (VDDS), herbal medicines can be delivered at a predetermined rate and can exhibit site-specific action. Vesicular drug delivery systems are novel pharmaceutical formulations that make use of vesicles as a means of encapsulating and transporting drugs to various locations within the body; they are a cutting-edge method of medication delivery that combats the drawbacks of conventional drug delivery methods. Drug delivery systems offer promising strategies to overcome the bioavailability limitations of bioactive phytochemicals. By improving their solubility, protecting them from degradation, enabling targeted delivery, and facilitating controlled release, drug delivery systems can enhance the therapeutic efficacy of phytochemicals and unlock their full potential in various health conditions. This review explores and collates the application of plant-based VDDS with the potential to exhibit protective effects against lung function loss in the interest of innovative and effective treatment and management of respiratory illnesses.

MFGE-8 identified in fetal mesenchymal-stromal-cell-derived exosomes ameliorates acute hepatic failure pathology

Liver transplantation is the gold-standard therapy for acute hepatic failure (AHF) with limitations related to organ shortage and life-long immunosuppressive therapy. Cell therapy emerges as a promising alternative to transplantation. We have previously shown that IL-10 and Annexin-A1 released by amniotic fluid human mesenchymal stromal cells (AF-MSCs) and their hepatocyte progenitor-like (HPL) or hepatocyte-like (HPL) cells induce liver repair and downregulate systemic inflammation in a CCl4-AHF mouse model. Herein, we demonstrate that exosomes (EXO) derived from these cells improve liver phenotype in CCl4-induced mice and promote oval cell proliferation. LC-MS/MS proteomic analysis identified MEFG-8 in EXO cargo that facilitates rescue of AHF by suppressing PI3K signaling. Administration of recombinant MFGE-8 protein also reduced liver damage in CCl4-induced mice. Clinically, MEFG-8 expression was decreased in liver biopsies from AHF patients. Collectively, our study provides proof-of-concept for an innovative, cell-free, less immunogenic, and non-toxic alternative strategy for AHF.

Mesenchymal Stem Cell Conditioned Medium Modulates Inflammation in Tenocytes: Complete Conditioned Medium Has Superior Therapeutic Efficacy than Its Extracellular Vesicle Fraction

Tendinopathy, a prevalent overuse injury, lacks effective treatment options, leading to a significant impact on quality of life and socioeconomic burden. Mesenchymal stem/stromal cells (MSCs) and their secretome, including conditioned medium (CM) and extracellular vesicles (EVs), have shown promise in tissue regeneration and immunomodulation. However, it remains unclear which components of the secretome contribute to their therapeutic effects. This study aimed to compare the efficacy of CM, EVs, and the soluble protein fraction (PF) in treating inflamed tenocytes. CM exhibited the highest protein and particle concentrations, followed by PF and EVs. Inflammation significantly altered gene expression in tenocytes, with CM showing the most distinct separation from the inflamed control group. Treatment with CM resulted in the most significant differential gene expression, with both upregulated and downregulated genes related to inflammation and tissue regeneration. EV treatment also demonstrated a therapeutic effect, albeit to a lesser extent. These findings suggest that CM holds superior therapeutic efficacy compared with its EV fraction alone, emphasizing the importance of the complete secretome in tendon injury treatment.

Serum starvation affects mitochondrial metabolism of adipose-derived stem/stromal cells

BACKGROUND AIMS

A large part of mesenchymal stromal cell (MSC) regenerative and immunomodulatory action is mediated by paracrine signaling. Hence, an increasing body of evidence acknowledges the potential of MSC secretome in a variety of preclinical and clinical scenarios. Mid-term serum deprivation is a common approach in the pipeline of MSC secretome production. Nevertheless, up to now, little is known about the impact of this procedure on the metabolic status of donor cells.

METHODS

Here, through untargeted differential metabolomics, we revealed an impairment of mitochondrial metabolism in adipose-derived MSCs exposed for 72 h to serum deprivation.

RESULTS

This evidence was further confirmed by the significant accumulation of reactive oxygen species and the reduction of succinate dehydrogenase activity. Probably as a repair mechanism, an upregulation of mitochondrial superoxide dismutase was also induced.

CONCLUSIONS

Of note, the analysis of mitochondrial functionality indicated that, despite a significant reduction of basal respiration and ATP production, serum-starved MSCs still responded to changes in energy demand. This metabolic phenotype correlates with the obtained evidence of mitochondrial elongation and branching upon starvation.

Human Osteochondral Explants as an Ex Vivo Model of Osteoarthritis for the Assessment of a Novel Class of Orthobiologics

Osteoarthritis (OA) is a highly prevalent joint disease still lacking effective treatments. Its multifactorial etiology hampers the development of relevant preclinical models to evaluate innovative therapeutic solutions. In the last decade, the potential of Mesenchymal Stem Cell (MSC) secretome, or conditioned medium (CM), has emerged as an alternative to cell therapy. Here, we investigated the effects of the CM from adipose MSCs (ASCs), accounting for both soluble factors and extracellular vesicles, on human osteochondral explants. Biopsies, isolated from total knee replacement surgery, were cultured without additional treatment or with the CM from 10⁶ ASCs, both in the absence and in the presence of 10 ng/mL TNFα. Tissue viability and several OA-related hallmarks were monitored at 1, 3 and 6 days. Specimen viability was maintained over culture. After 3 days, TNFα induced the enhancement of matrix metalloproteinase activity and glycosaminoglycan release, both efficiently counteracted by CM. The screening of inflammatory lipids, proteases and cytokines outlined interesting modulations, driving the attention to new players in the OA process. Here, we confirmed the promising beneficial action of ASC secretome in the OA context and profiled several bioactive factors involved in its progression, in the perspective of accelerating an answer to its unmet clinical needs.

Secretomes as an emerging class of bioactive ingredients for enhanced cosmeceutical applications

Skin aging is predominantly caused by either intrinsic or extrinsic factors, leading to undesirable skin features. Advancements in both molecular and cellular fields have created possibilities in developing novel stem cell-derived active ingredients for cosmeceutical applications and the beauty industry. Mesenchymal stromal cell (MSC)-derived secretomes or conditioned media hold great promise for advancing skin repair and regeneration due to the presence of varying cytokines. These cytokines signal our cells and trigger biological mechanisms associated with anti-inflammatory, antioxidant, anti-aging, proliferative, and immunomodulatory effects. In this review, we discuss the potential of MSC secretomes as novel biomaterials for skincare and rejuvenation by illustrating their mechanism of action related to wound healing, anti-aging, and whitening properties. The advantages and disadvantages of secretomes are compared to both plant-based and animal-derived extracts. In addition, this paper reviews the current safety standards, regulations, market products and research work related to the cosmeceutical applications of secretomes along with strategies to maintain and improve the therapeutic efficacy and production of secretomes. The future outlook of beauty industry is also presented. Lastly, we highlight significant challenges to be addressed for the clinical realization of MSC secretomes-based skin therapies as well as providing perspectives for the future direction of secretomes.

Towards Secretome Standardization: Identifying Key Ingredients of MSC-Derived Therapeutic Cocktail

The therapeutic potential of the conditioned medium (CM) derived from MSCs (mesenchymal stem/stromal cells) in disparate medical fields, from immunology to orthopedics, has been widely suggested by in vitro and in vivo evidences. Prior to MSC-CM use in clinical applications, appropriate quality controls are needed in order to assess its reproducibility. Here, we evaluated different CM characteristics, including general features and precise protein and lipid concentrations, in 3 representative samples from adipose-derived MSCs (ASCs). In details, we first investigated the size and distribution of the contained extracellular vesicles (EVs), lipid bilayer-delimited particles whose pivotal role in intercellular communication has been extensively demonstrated. Then, we acquired Raman signatures, providing an overlook of ASC-CM composition in terms of proteins, lipids, and nucleic acids. At last, we analyzed a panel of 200 molecules including chemokines, cytokines, receptors, and inflammatory and growth factors and searched for 32 lipids involved in cell signalling and inflammation. All ASC-CM contained a homogeneous and relevant number of EVs (1.0 × 10⁹ ± 1.1 × 10⁸ particles per million donor ASCs) with a mean size of 190 ± 5.2 nm, suggesting the appropriateness of the method for EV retaining and concentration. Furthermore, also Raman spectra confirmed a high homogeneity among samples, allowing the visualization of specific peaks for nucleic acids, proteins, and lipids. An in depth investigation that focused on 200 proteins involved in relevant biological pathways revealed the presence in all specimens of 104 factors. Of these, 26 analytes presented a high degree of uniformity, suggesting that the samples were particularly homogenous for a quarter of the quantified molecules. At last, lipidomic analysis allowed the quantification of 7 lipids and indicated prostaglandin-E2 and N-stearoylethanolamide as the most homogenous factors. In this study, we assessed that ASC-CM samples obtained with a standardized protocol present stable features spanning from Raman fingerprint to specific marker concentrations. In conclusion, we identified key ingredients that may be involved in ASC-CM therapeutic action and whose consistent levels may represent a promising quality control in the pipeline of its preparation for clinical applications.