Exosomes are nano‐sized bioactive vesicles of 30–150 nm in diameter. They are secreted by exocytosis of nearly all type of cells in to the extracellular fluid. Thereby, they can be found in many biological fluids. Exosomes regulate intracellular communication between cells via delivery of their cargo which include lipids, proteins, and nucleic acid. Many desirable features of exosomes made them promising candidates in several therapeutic applications. In this review, we discuss the use of exosomes as diagnostic tools and their possible biomedical applications. Additionally, current techniques used for isolation, purification, and characterization of exosomes from both biological fluids and in vitro cell cultures were discussed.

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BACKGROUND: Community participation in physical activity is considered a major public health preference of WHO. Saudi Arabia in the last decades faced many tremendous economic changes leading to adoption of western dietary habits associated with sedentary lifestyle. AIM: We aimed to study the relationship between both physical activity knowledge and attitude of community to the practice of individuals. METHODS: We used a questionnaire consists of a mixture of closed-ended questions. Participants were recruited through direct meetings in local markets, schools, and workplaces. Seven hundred and sixty six individuals agreed to participate. RESULTS: Overall correct answers to questions about importance of physical activity were 76.58%. The predominance of participants’ attitude was to establish public places for physical activity in each neighborhood (92.1%). Participants acknowledged that they exercise to improve their health (47.5%). Participants mainly perform light exercises (47.2%) on basis of 1–3 times weekly (48.9%). About 90.8% of participants admitted that they like to increase duration of their physical activity. CONCLUSIONS: Overall physical activity practice of participants’ needs encourage overcoming obstacles that prevent individuals from practicing especially lack of time.

Since the end of 2019, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has spread as a new strain of coronavirus disease (COVID‐19) and progressed as a global pandemic. Exosomes are membrane‐bound vesicles released from almost all cells and are crucially involved in cell–cell communication. Interestingly, COVID‐19 viral particles produce exosomes that moderate communication between infected and uninfected cells. Hence, there is growing evidence highlighting the crucial implications of exosomes in COVID‐19 infection, transmission, intercellular spread, and reinfection. On the other hand, clinical trials have demonstrated mesenchymal stem cell‐derived exosomes as a promising therapeutic strategy for severely affected COVID‐19 patients. Also, convalescent plasma‐derived exosomes have been proposed for multiple efficacies in COVID‐19 patients. Furthermore, messenger RNAs (mRNA)‐loaded exosomes were superior to mRNA‐loaded lipid nanoparticles as a delivery system. Hence, exosomes can be used to safely induce SARS‐CoV‐2 immunity via their loading with mRNAs encoding immunogenic forms of SARS‐CoV‐2 spike and nucleocapsid proteins. Moreover, exosomes can be used as a nano‐delivery system for microRNA to alleviate cytokine storm and prevent the progression of organ failure in COVID‐19 patients. The present review summarizes state of the art concerning the role of exosomes in COVID‐19 infection and accompanying organ complications as well as the potential use of exosomes in COVID‐19 diagnosis, treatment, drug delivery, and vaccination. The review also sheds the light on the common biogenic pathway between the SARS‐CoV‐2 virus and exosomes. Additionally, the latest and current clinical trials using exosomes for COVID‐19 infection are summarized.

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