Treatment of Sleep Disordered Breathing with Leptin Loaded Extracellular Vesicles

Obstructive sleep apnea (OSA) is the most common type of sleep disordered breathing (SDB), characterized by recurrent periods of upper airway obstruction during sleep leading to increase in morbidity and mortality. The prevalence of OSA exceeds 50% in individuals with obesity and 10-20% also develop hypercapnia and hypoventilation during sleep which characterizes obesity hypoventilation syndrome (OHS). There is no effective pharmacotherapy for SDB. Leptin, an adipocyte derived hormone, can stimulate breathing and is a potential therapeutic candidate. However, diet-induced obesity is associated with impairment of leptin transport across the blood-brain barrier. Previous studies have shown that extracellular vesicles (EVs) naturally derived from macrophages can penetrate the BBB and be used for drug delivery. The objective of this study was to determine if EVs overcome the BBB and treat SDB in DIO mice.To examine the ability of EVs to cross the BBB, lean (n=5) and DIO (n=5) C57BL/6J mice were injected with fluorescent EVs or saline into the lateral tail vein. After 4h EV biodistribution was evaluated by Bioimaging and Infrared Spectroscopy (IVIS). Sleep studies were performed in a plethysmography chamber in a separate subgroup of male, DIO (n=10) and lean (n=10) mice. Mice received saline, empty exosomes, free leptin, or leptin-loaded exosomes in a crossover manner. Similar design was used to determine energy expenditure in a Comprehensive Laboratory Animal Monitoring System (CLAMS).We demonstrated that EVs accumulated in the brain and the transport across the BBB was 2-times more efficient in DIO when compared to lean mice (p<0.005). In DIO mice, leptin EVs induced 1.7-2.2-fold increases in minute ventilation and 1.5-2.0-fold increases in maximal inspiratory flow during flow-limited and non-flow limited breaths (p<0.05). In contrast, free leptin had no effect. There was no effect of leptin EVs on metabolism. These findings suggest that leptin EVs mitigated upper airway obstruction and improved control of breathing in DIO mice. Lean mice did not present significant sleep disordered breathing and no differences were observed between groups.We demonstrated that EVs overcome the BBB and that leptin loaded EVs treat SDB in DIO mice.