Adipose tissue as a buffer for daily lipid flux

Area of Science:

• Metabolic disease
• Endocrinology
• Lipid metabolism

Background:

• Insulin resistance is a hallmark of obesity and Type II diabetes, and also prominent in lipodystrophy.
• Adipose tissue plays a key role in managing circulating fatty acids post-meal, similar to how other tissues manage glucose.
• Impaired buffering capacity of adipose tissue can lead to lipid accumulation in non-adipose tissues, causing insulin resistance.

Purpose of the Study:

• To investigate the role of adipose tissue in buffering postprandial fatty acid flux.
• To elucidate the mechanisms underlying insulin resistance in conditions of both excess and deficiency of adipose tissue.
• To explore the implications of adipose tissue buffering capacity for understanding insulin resistance and therapeutic interventions.

Main Methods:

• The study conceptually reviews the physiological role of adipose tissue in lipid metabolism.
• It analyzes the consequences of impaired adipose tissue buffering on extra-adipose tissues.
• The research framework integrates findings related to obesity, lipodystrophy, and insulin sensitivity.

Main Results:

• Adipose tissue buffers circulating fatty acids by suppressing release and enhancing triacylglycerol clearance via "fatty acid trapping."
• Impaired adipose tissue buffering leads to triacylglycerol accumulation in liver, muscle, and pancreatic beta cells, resulting in insulin resistance and impaired insulin secretion.
• Both obesity (impaired response) and lipodystrophy (insufficient capacity) demonstrate impaired adipose tissue buffering, leading to similar insulin resistance phenotypes.

Conclusions:

• Adipose tissue's buffering capacity is critical for preventing ectopic lipid accumulation and maintaining insulin sensitivity.
• The concept of adipose tissue buffering provides a unified explanation for insulin resistance in obesity and lipodystrophy.
• Understanding adipose tissue buffering may offer insights into the mechanisms of insulin-sensitizing drugs like thiazolidinediones.