Low-Frequency Intermittent Hypoxia Promotes Subcutaneous Adipogenic Differentiation

Area of Science:

• Physiology
• Metabolic Disorders
• Obesity Research

Background:

• Obstructive sleep apnea (OSA) involves intermittent hypoxia (IH), linked to obesity and metabolic issues.
• Adipogenesis, the creation of fat cells, is crucial for adipose tissue mass and function.
• The specific effects of low-frequency IH on adipogenesis remain largely uninvestigated.

Purpose of the Study:

• To investigate the impact of low-frequency intermittent hypoxia on adipogenesis.
• To explore the underlying molecular mechanisms, including the IGF-1R/Akt pathway, in human preadipocytes.

Main Methods:

• Rats were exposed to IH or intermittent normoxia (IN) for six weeks.
• Adipogenic differentiation was assessed using transcriptional factors and protein markers in subcutaneous (SAT) and visceral (VAT) adipose tissue.
• In vitro studies used human preadipocytes (HPAs) subjected to IH or IN, with and without an IGF-1R inhibitor.

Main Results:

• IH exposure in rats upregulated proadipogenic markers (CEBPα, PPARγ, FABP4) and downregulated an antiadipogenic marker (CHOP) in SAT, with smaller adipocyte size.
• In vitro, IH promoted oily droplet accumulation and adipogenesis markers in HPAs.
• The IGF-1R kinase inhibitor NVP-AEW541 counteracted the proadipogenic effects of IH in HPAs.

Conclusions:

• Low-frequency intermittent hypoxia may enhance adipogenesis, particularly in subcutaneous adipose tissue.
• The IGF-1R/Akt pathway appears to mediate the proadipogenic effects of IH in human preadipocytes.