Previous studies have revealed that muscle atrophy emerges as a significant challenge faced by astronauts during prolonged missions in space. A loss in muscle mass results in a weakening of skeletal muscle strength and function, which will not only contribute to a decline in overall physical performance but also elevate the risk of various age-related diseases. Skeletal muscle atrophy in the microgravity environment is thought to be associated with changes in energy metabolism, protein metabolism, calcium ion homeostasis, myostatin levels, and apoptosis. Modulating some pathways could be a promising approach to mitigating muscle atrophy in the microgravity environment. This review serves as a comprehensive summary of research on the impact of microgravity on skeletal muscle, with the aim of providing insights into its pathogenesis and the development of effective treatments.

Peripheral nerve injury (PNI) remains a significant clinical challenge, often leading to long-term functional impairment. Despite advances in therapies, current repair strategies offer unsatisfactory clinical outcomes. Exosomes derived from induced pluripotent stem cells (iPSC-Exos) have emerged as a promising therapeutic approach in regenerative medicine. This study assesses the efficacy and safety of iPSC-Exos in a rat model of sciatic nerve crush injury. Briefly, iPSCs were generated from peripheral blood mononuclear cells (PBMCs) of healthy donors using Sendai virus vectors and validated for pluripotency. iPSC-Exos were characterized and injected at the injury site. Functional recovery was assessed through gait analysis, grip strength, and pain response. Histological and molecular analyses were used to examine axonal regeneration, myelination, Schwann cell (SC) activation, angiogenesis, and changes in gene expression. iPSC-Exos were efficiently internalized by SC, promoting their proliferation. No adverse effects were observed between groups on body weight, organ histology, or hematological parameters. iPSC-Exos injection significantly enhanced nerve regeneration, muscle preservation, and vascularization, with RNA sequencing revealing activation of PI3K-AKT and focal adhesion pathways. These findings support iPSC-Exos as a safe and effective non-cell-based therapy for PNIs, highlighting their potential for clinical applications in regenerative medicine.

Small extracellular vesicles (sEVs), including exosomes as a subtype, with a diameter typically less than 200 nm and originating from the endosomal system, are capable of transporting a diverse array of bioactive molecules, including proteins, nucleic acids, and lipids, thereby facilitating intercellular communication and modulating cellular functions. Vascular dementia (VaD) represents a form of cognitive impairment attributed to cerebrovascular disease, characterized by a complex and multifaceted pathophysiological mechanism. Currently, the therapeutic approach to VaD predominantly emphasizes symptom management, as no specific pharmacological treatment exists to cure the condition. Recent investigations have illuminated the significant role of sEVs in the pathogenesis of vascular dementia. This review seeks to provide a comprehensive analysis of the characteristics and functions of sEVs, with a particular focus on their involvement in vascular dementia and its underlying mechanisms. The objective is to advance the understanding of the interplays between sEVs and vascular dementia, thereby offering novel insights for future research and therapeutic strategies.