Spinal cord injury has challenging and unpredictable neurological recovery. During inflammatory conditions, the amount of serum albumin and nutrition consumption decrease, nowadays, it is proposed to measure serum albumin and glucose content in human or animal subjects to predict the recovery rate and the efficiency of treatments following SCI. In this study, the effect of extracellular vesicles (EVs) from immortalized human adipose tissue-derived mesenchymal stem cells (Ad-MSCs) equipped with the ectopic expression of human IDO1 gene was investigated on the serum albumin and glucose levels. After pre-clearing steps of 72-hour conditioned media, small EVs (sEVs) were isolated based on the ultrafiltration method. They were encapsulated with a chitosan-based hydrogel. Five experimental groups (female rats, N=30, ~230 g) were considered, including SCI, sham, hydrogel, hTERT-MSCs-GFP-EVs, and hTERT-MSCs-IDO1-EVs. 60 µl of hydrogel or hydrogels containing 100 µg sEVs from control GFP-EVs or IDO1-EVs were locally injected immediately after SCI (laminectomy of the T10 and clip compression). Eight weeks later, non-fasting serum glucose and albumin levels were measured. Results indicated that the level of serum albumin in the animals received IDO1-EVs (3.52±0.04) was increased in comparison to the SCI group (3.00±0.94).Also, these animals indicated higher glucose levels in their serum (250.17±69.61) in comparison to SCI rats (214.00±45.34). Although, these changes were not statistically significant, this could be considered as an evidence for the beneficial effects of IDO1-EVs administration in the context of SCI to reduce hypoalbuminemia and improve energy consumption. However, more detailed experiments are required to confirm these results.

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