Current Pharmaceutical Design - Volume 25, Issue 42, 2019

Background: Exosomes open exciting new opportunities for advanced drug transport and targeted release. Furthermore, exosomes may be used for vaccination, immunosuppression or wound healing. To fully utilize their potential as drug carriers or immune-modulatory agents, the optimal purity of exosome preparations is of crucial importance. Methods: Articles describing the isolation and purification of exosomes were retrieved from the PubMed database. Results: Exosomes are often separated from biological fluids containing high concentrations of proteins, lipids and other molecules that keep vesicle purification challenging. A great number of purification protocols have been published, however, their outcome is difficult to compare because the assessment of purity has not been standardized. In this review, we first give an overview of the generation and composition of exosomes, as well as their multifaceted biological functions that stimulated various medical applications. Finally, we describe various methods that have been used to purify small vesicles and to assess the purity of exosome preparations and critically compare the quality of these evaluation protocols. Conclusion: Combinations of various techniques have to be applied to reach the required purity and quality control of exosome preparations.

Sepsis is the leading cause of death in medical intensive care units, and thus represents a serious healthcare problem worldwide. Sepsis is often caused by the aberrant host responses to infection, which induce dysregulated inflammation that leads to life-threatening multiple organ failures. Mediators such as proinflammatory cytokines that drive the sepsis pathogenesis have been extensively studied. Exosomes, biological lipid bilayer nanoparticles secreted via the endosomal pathway of cells, have recently emerged as important cargos that carry multiple mediators critical for the pathogenesis of sepsis-associated organ dysfunctions. Here we will review current knowledge on the exosomes in sepsis and relevant inflammatory tissue injuries.

Exosomes are nano-sized extracellular vesicles that are released by a variety of cells. Exosomes contain cargo from cells they derived, including lipids, proteins and nucleic acids. The bilayer lipid membrane structure of exosomes protects these contents from degradation, allowing them for intercellular communication. The role of exosomes in fibrotic diseases is increasingly being valued. Exosomes, as carriers of profibrotic signals, are involved in the development of fibrotic diseases, and also regulate fibrosis by transmitting signals that inhibit fibrosis or inflammation. Exosomes mobilize and activate a range of effector cells by targeted delivery of bioactive information. Exosomes can also reflect the condition of cells, tissues and organisms, and thus become potential biomarkers of fibrotic diseases. Exosomes from bone marrow stem cells support biological signaling that regulates and inhibits fibrosis and thus initially used in the treatment of fibrotic diseases. This article briefly summarizes the role of exosomes in the pathogenesis and treatment of fibrotic diseases and raises some issues that remain to be resolved.

Exosomes are extracellular vesicles produced by eukaryotic cells that are also found in most biological fluids and tissues. While they were initially thought to act as compartments for removal of cellular debris, they are now recognized as important tools for cell-to-cell communication and for the transfer of pathogens between the cells. They have attracted particular interest in neurodegenerative diseases for their potential role in transferring prion-like proteins between neurons, and in Parkinson’s disease (PD), they have been shown to spread oligomers of α-synuclein in the brain accelerating the progression of this pathology. A potential neuroprotective role of exosomes has also been equally proposed in PD as they could limit the toxicity of α-synuclein by clearing them out of the cells. Exosomes have also attracted considerable attention for use as drug vehicles. Being nonimmunogenic in nature, they provide an unprecedented opportunity to enhance the delivery of incorporated drugs to target cells. In this review, we discuss current knowledge about the potential neurotoxic and neuroprotective role of exosomes and their potential application as drug delivery systems in PD.

Exosomes are phospholipid bilayer-enclosed membrane vesicles derived and constitutively secreted by various metabolically active cells. They are capable of mediating hetero- and homotypic intercellular communication by transferring multiple cargos from donor cells to recipient cells. Nowadays, non-coding RNAs (ncRNAs) have emerged as novel potential biomarkers or disease-targeting agents in a variety of diseases. However, the lack of effective delivery systems may impair their clinical application. Recently, accumulating evidence demonstrated that ncRNAs could be efficiently delivered to recipient cells using exosomes as a carrier, and therefore can exert a critical role in musculoskeletal diseases including osteoarthritis, rheumatoid arthritis, osteoporosis, muscular dystrophies, osteosarcoma and other diseases. Herein, we present an extensive review of biogenesis, physiological relevance and clinical implication of exosome-derived ncRNAs in musculoskeletal diseases.

Exosomes, which mediate cell-to-cell communications and provide a novel insight into information exchange, have drawn increasing attention in recent years. The homeostasis of bone metabolism is critical for bone health. The most common bone diseases such as osteoporosis, osteoarthritis and bone fractures have apparent correlations with exosomes. Accumulating evidence has suggested the potential regenerative capacities of stem cell-derived exosomes. In this review, we summarise the pathophysiological mechanism, clinical picture and therapeutic effects of exosomes in bone metabolism. We introduce the advantages and challenges in the application of exosomes. Although the exact mechanisms remain unclear, miRNAs seem to play major roles in the exosome.