Females' “healthier fat” protects them from obesity-related health issues, mice study finds

24 Oct 2018 --- Female abdominal fat, in mice, has more blood vessels than males' which may explain why males and females differ in susceptibility to cardiovascular disease, insulin resistance and diabetes, notes research from York University, Canada. Previously, it was noted that female fat tissue tends to be more protective against health issues, such as diabetes and cardiovascular disease, than male fat tissue but the underlying reasons were not understood. Understanding the underlying mechanisms behind sex differences in cellular processes are important as they may contribute to individual's susceptibility to develop serious health issues.

“We found that female mice have a higher number of blood vessels in their fat than males and that females increase the number of blood vessels as they are fed a high-fat diet, while males do not. We concluded that this response enabled females to maintain healthier fat and better insulin sensitivity as they grew fat,” says Tara Haas, a Professor in the School of Kinesiology and Health Science, Faculty of Health.

Blood vessels are critical for maintaining healthy fat tissue by ensuring that the expanding fat cells are supplied with enough oxygen and nutrients, so the researchers looked at whether the abilities of the fat tissue to grow blood vessels and maintain healthy fat tissue would be different between males and females.

The sex differences in the fundamental cellular processes that regulate the growth of blood vessels were unappreciated in the past, says Haas. It is important to understand them because they may contribute to an individual's susceptibility to develop serious obesity-related health complications such as diabetes, heart disease and cancer, ultimately impacting the health of more than 5.3 million Canadian adults.

Martina Rudnicki, a York post-doctoral Associate and first author of the study, pointed out that the study, published in Frontiers in Physiology – Vascular Physiology, was unique because it focused on the differences in male and female fat tissue in the abdominal area. 

Although fat accumulates in different regions of the body, it is abdominal fat that is closely linked with increased risk of developing diabetes, particularly in males. So, the fact that females grow new blood vessels in this abdominal fat during weight gain may exert a health advantage for females.

The research team plans to confirm these findings in human samples. While it is clear that females also develop health problems with obesity, the fact that there was such a difference in the vascularization in male and female fat may mean it would be more effective to have different treatments for males and females.