Sleep-disordered breathing, circulating exosomes, and insulin sensitivity in adipocytes

Area of Science:

• Metabolic dysfunction
• Cellular biology
• Sleep medicine

Background:

• Sleep-disordered breathing (SDB), characterized by intermittent hypoxia (IH) and sleep fragmentation (SF), is linked to metabolic dysfunction, especially in obstructive hypoventilation syndrome (OHS).
• Exosomes, circulating vesicles, can alter cellular functions, but their impact on adipocyte metabolism in OHS or SDB models is not well understood.

Purpose of the Study:

• To investigate the effects of plasma exosomes from patients with OHS and SDB animal models on adipocyte metabolism.
• To determine if CPAP therapy can ameliorate exosome-induced metabolic changes.

Main Methods:

• Plasma exosomes were isolated from obese adults with obstructive sleep apnea (OSA) before and after CPAP treatment, and from mice exposed to sleep fragmentation (SF) or intermittent hypoxia (IH).
• Exosomes were co-cultured with naive human and murine adipocytes.
• Insulin sensitivity was assessed via Akt phosphorylation, and lipolysis was measured by glycerol content.

Main Results:

• Exosomes from OHS patients and SDB mice reduced insulin-induced Akt phosphorylation in adipocytes, mimicking insulin resistance.
• OHS exosomes increased adipocyte lipolysis, an effect attenuated by CPAP therapy.
• Exosomes from SF- and IH-exposed mice similarly impaired insulin signaling and increased lipolysis in murine adipocytes.

Conclusions:

• Alterations in plasma exosomal cargo in SDB contribute to adipocyte metabolic dysfunction.
• CPAP therapy appears to reverse these detrimental exosome-mediated effects.
• Further research into exosomal miRNA signatures in SDB is warranted to identify therapeutic targets.