Gelatinase B (MMP-9) deficiency does not affect murine adipose tissue development

Area of Science:

• Biochemistry
• Physiology
• Obesity Research

Background:

• Gelatinase A (MMP-2) deficiency is known to impair adipose tissue development.
• Gelatinase B (MMP-9) is a functional homologue of MMP-2, prompting investigation into its role in adipose tissue growth.

Purpose of the Study:

• To evaluate the role of gelatinase B (MMP-9) in adipose tissue growth.
• To assess MMP-9 antigen levels in lean and obese women before and after weight loss.
• To examine the impact of MMP-9 deficiency on adipose tissue development in mice on a high-fat diet.

Main Methods:

• MMP-9 serum levels were measured in human subjects (lean and obese) and correlated with body mass index and weight loss.
• MMP-9-deficient mice and wild-type littermates were fed a high-fat diet for 15 weeks.
• Analysis of subcutaneous and gonadal fat pads in mice included weight, adipocyte size/density, and blood vessel characteristics.

Main Results:

• Obese women exhibited higher MMP-9 serum levels than lean controls; levels decreased after weight loss.
• MMP-9-deficient mice and wild-type controls showed no significant differences in body weight or fat weight on a high-fat diet.
• MMP-9 deficiency did not affect adipocyte or blood vessel size/density in mouse adipose tissue depots.

Conclusions:

• Human body mass index positively correlates with serum MMP-9 levels.
• MMP-9 does not appear to play a significant role in adipose tissue development in murine models of diet-induced obesity.