PhD defence K. (Kasiphak) Kaikaew

Excessive or abnormal fat accumulation in the body causes overweight and obesity. There are two types of adipose tissue which serve opposite roles: lipid-storing white adipose tissue (WAT) and thermogenic lipid-burning brown adipose tissue (BAT). Males and females display differences in adipose tissue distribution and function. Compared to men, women typically have a higher percentage of body fat but accumulate less fat in the intra-abdominal part of the body, and have greater prevalence of active BAT. These differences explain in part why women before menopause have a lower incidence of metabolic diseases. However, the mechanisms underlying these sex differences are not completely understood. Using mouse and human studies, this thesis broadens our understanding of sex differences in control of adipose tissues in many aspects. First, adipose tissues of female mice adapted in a more metabolically protective way upon exposure to stress hormones compared to male mice. Second, the gene expression profile of classical BAT depot differs between male and female mice and this sex difference persisted when brown fat cells are cultured in vitro. Third, female mice prefer residing in a warmer environment than male mice and women started shivering at a higher temperature than men. These sex-biased thermal perception is important for optimal thermoregulation which may explain the sex difference in BAT thermogenesis. In conclusion, our findings strengthen the rationale that sex should be included as an independent biological variable. However, more studies are warranted to fully understand this complex picture of sexual dimorphisms in adipose tissue biology.

The public defence will take place at the Prof. Andries Queridoroom, 3rd floor Education Center, Erasmus MC. The ceremony will begin exactly at 13.30 hrs. In light of the solemn nature of the ceremony, we recommend that you do not take children under the age of 6 to the first part of the ceremony.