Related Experiment Videos
Intermittent hypoxia induces hyperlipidemia in lean mice
Jianguo Li1, Laura N Thorne, Naresh M Punjabi
1Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Md, USA.
Circulation Research
|August 27, 2005
Summary
Intermittent hypoxia (IH) from sleep apnea increases cholesterol and triglycerides in lean mice. However, IH does not worsen lipid issues in obese mice with existing metabolic problems.
Area of Science:
- Metabolic Physiology
- Sleep Medicine
- Cardiovascular Research
Background:
- Obstructive sleep apnea (OSA) is linked to hypercholesterolemia, irrespective of obesity.
- Recurrent intermittent hypoxia (IH) is a hallmark of OSA, potentially impacting lipid metabolism.
- Understanding IH's specific effects on lipid profiles is crucial for targeted interventions.
Purpose of the Study:
- To investigate the impact of experimentally induced IH on serum lipid levels and hepatic lipid metabolism pathways.
- To compare these effects in lean versus obese states, using a mouse model.
- To elucidate the molecular mechanisms underlying IH-induced metabolic alterations.
Main Methods:
- Lean and leptin-deficient obese mice were exposed to IH for five days.
- Serum lipid profiles (cholesterol, HDL, phospholipids, triglycerides) were analyzed.
- Liver lipid content and the expression of key lipid metabolism genes (SREBP-1, SCD-1, SR-B1) were assessed.
Main Results:
- In lean mice, IH significantly increased serum total cholesterol, HDL cholesterol, phospholipids, and triglycerides.
- IH also elevated liver triglyceride content and upregulated hepatic SREBP-1 and SCD-1 expression and activity in lean mice.
- Obese mice exhibited baseline hyperlipidemia and fatty liver; IH did not exacerbate these conditions.
Conclusions:
- Short-term IH exposure in lean mice dysregulates lipid metabolism, increasing lipid synthesis and decreasing hepatic cholesterol uptake.
- These effects are distinct from the metabolic disturbances seen in established obesity.
- IH-induced metabolic changes in lean individuals may contribute to cardiovascular risk associated with sleep apnea.