Investigation of the effects of cold stress on angiogenic factors in adipose tissue of obese rats

Abstract

Adipose tissue produces both vascular growth factors and inhibitors. Since obesity is associated with expansion of the capillary bed in regional adipose depots the balance between these factors may favor angiogenesis. White and brown adipose tissues (WAT and BAT) plasticity, namely the ability to expand, plays a critical role in the regulation of body energy balance. as a thermogenic organ, the activity of BAT counteracts the obesity. BAT possesses extraordinarily complex vascular networks to support its high thermogenic activity. It also meets the needs of supplying oxygen and substrates to fuel thermogenesis and distributing heat throughout the body rapidly. Brown adipose tissue is related to thermogenesis while white adipose tissue is the shape of storage of high‐calorie foods. The temperature conditions, when normal and above, cause a decrease in the activity of brown adipose tissue which plays a role in the regulation of body temperature while the nutrients are collected as adipocytes instead of being consumed as heat. Therefore, in this study, we aimed to compare the differences in angiogenic/antiangiogenic factor levels in normal and obese rats due to cold application and to investigate possible changes in brown adipose tissue due to the application of cold stress. Vascular endothelial growth factor (VEGF), matrix metalloproteinase II (MMP‐II), hypoxia inducible factor 1α (HIF1‐α), angiostatin ve endostatin concentrations were measured in brown adipose tissue (BAT) and white adipose tissue (WAT) from 12 control (6 rats kept in room temperature, 6 rats kept in 10 °C for 72 h) and 12 obese (6 rats kept in room temperature and 6 rats kept in 10 °C for 72 h). All animals were 6 months old. In our the study, vascular endothelial growth factor (VEGF), matrix metalloproteinase‐II, hypoxia inducible factor 1α, angiostatin and endostatin levels were investigated. While angiogenic factors increased in cold stress application in control animals, antiangiogenic factors decreased. Angiogenic factors decreased due to cold stress application and increased in antiangiogenic factors in obese animals. Antiangiogenic factors were found to be increased in brown adipose tissue and angiogenic factors increased in white adipose tissue. It was observed that the increase in antiangiogenic factors was more evident in brown fat tissue of obese rats exposed to cold stress. In addition to nutritional conditions, it is concluded that the temperature conditions of the body are effective on angiogenic/antiangiogenic factors and may be effective on brown fat tissue which plays a role in thermogenesis. It should be evaulated that increased levels of antiangiogenic factors are in obese rats may contribute to reducing adipose tissue activity in cope with obesity.Support or Funding InformationThis research was funded by Inonu University, Department of Scientific Research Projects Project No: FYL‐2018‐943).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.