Intermittent cold exposure enhances fat accumulation in mice

Area of Science:

• Metabolic research
• Adipose tissue biology
• Energy homeostasis

Background:

• Brown adipose tissue (BAT) is crucial for energy metabolism due to its high energy consumption.
• Cold exposure activates BAT, and intermittent cold exposure (ICE) is a clinically feasible method.
• The impact of ICE on overall adiposity and metabolic pathways requires further investigation.

Purpose of the Study:

• To determine if intermittent cold exposure (ICE) reduces adiposity in C57BL/6 mice.
• To investigate the effects of ICE on BAT activation, beige adipocyte induction, and lipogenesis.
• To assess the impact of ICE on systemic insulin sensitivity and liver triglyceride metabolism.

Main Methods:

• C57BL/6 mice were subjected to intermittent cold exposure (ICE).
• Adiposity, Ucp1 expression, and beige adipocyte markers were assessed.
• Systemic insulin sensitivity, liver triglyceride content, and blood triglyceride levels were measured.
• Gene expression profiling of lipogenic pathways in white adipose tissue and liver was performed.

Main Results:

• ICE unexpectedly increased adiposity in mice.
• Ucp1 expression in BAT and beige adipocyte induction in subcutaneous white adipose tissue were enhanced.
• Basal systemic insulin sensitivity remained unchanged, but liver triglyceride content and secretion, along with blood triglyceride levels, increased.
• Lipogenesis was enhanced between cold exposure periods, despite suppression during exposure.

Conclusions:

• Intermittent cold exposure (ICE) does not reduce adiposity in mice and can lead to increased fat accumulation.
• ICE promotes BAT recruitment and beige adipogenesis but stimulates de novo lipogenesis, contributing to increased fat storage.
• The findings suggest a complex interplay between cold exposure, BAT activation, and lipogenic pathways that results in enhanced adiposity.