The adipose tissue is responsible for fat storage and is the major producer of exosomes. Biological content transported by the exosomes provides information, such as immunometabolic alterations. This study aimed to isolate whole exosomes from plasma and supernatant of differentiated 3T3-L1 cells using three isolation techniques. Plasma from 120 individuals categorized by body adipose tissue proportion and differentiated 3T3-L1 cells were used in this study. The exosome isolation techniques were differential centrifugation (DC), size exclusion chromatography (SEC), and a commercial kit (Invitrogen), and characterized by cryo-TEM, TEM, and western blot for the tetraspanins CD9 and CD81. In the three isolation techniques, cryo-TEM and TEM analysis showed similar quality, quantity, and morphology of exosomes; at the same time, no difference was observed between individuals categorized by proportion of body fat. According to our results, the concentration of the circulating exosomes is not different between normal and high-fat percentage individuals, but rather their composition. The SEC and kit commercial proved that compile with most of the advantages of an exosome isolation technique, nerveless we emphasize the importance of selecting the appropriate methodology depending on the specific research objectives.

Trauma to the spinal cord causes extensive neuronal death contributing to the loss of sensory-motor and autonomic functions below the injury level. Apoptosis affects neurons after spinal cord injury (SCI) and is associated with increased caspase activity. Cleavage of X-linked inhibitor of apoptosis protein (XIAP) after SCI may contribute to this rise of caspase activity. Accordingly, we have shown that the elevation of XIAP resulted in increased neuronal survival after SCI and improved functional recovery. Therefore, we hypothesize that neuronal overexpression of XIAP can be neuroprotective after SCI with improved functional recovery. In line with this, studies of a transgenic mouse with overexpression of XIAP in neurons revealed that higher levels of XIAP after spinal cord trauma favours neuronal survival, tissue preservation, and motor recovery after the spinal cord trauma. Using the human SH-SY5Y cells overexpressing XIAP we show further that XIAP reduced caspase activity and apoptotic cell death after pro-apoptotic stimuli. In conclusion, this study shows that the levels of XIAP expression are an important factor for the outcome after spinal cord trauma and identifies XIAP as an important therapeutic target for alleviating the deleterious effects of SCI.