Adipogenesis in Obesity Requires Close Interplay Between Differentiating Adipocytes, Stromal Cells, and Blood Vessels

Adipogenesis in Obesity Requires Close Interplay Between Differentiating Adipocytes, Stromal Cells, and Blood Vessels Satoshi Nishimura 1 , Ichiro Manabe 1 2 3 , Mika Nagasaki 1 , Yumiko Hosoya 1 , Hiroshi Yamashita 1 , Hideo Fujita 1 , Mitsuru Ohsugi 4 , Kazuyuki Tobe 4 , Takashi Kadowaki 4 , Ryozo Nagai 1 and Seiryo Sugiura 5 1 Department of Cardiovascular Medicine, University of Tokyo, Tokyo, Japan 2 Nano-Bioengineering Education Program, Tokyo, Japan 3 PRESTO, Japan Science and Technology Agency, Kawaguchi City, Japan 4 Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo, Japan 5 Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, University of Tokyo, Tokyo, Japan Address correspondence and reprint requests to Seiryo Sugiura, Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, the University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan. E-mail: sugiura{at}k.u-tokyo.ac.jp Abstract OBJECTIVE—The expansion of adipose tissue mass seen in obesity involves both hyperplasia and hypertrophy of adipocytes. However, little is known about how adipocytes, adipocyte precursors, blood vessels, and stromal cells interact with one another to achieve adipogenesis. RESEARCH DESIGN AND METHODS—We have developed a confocal microscopy-based method of three-dimensional visualization of intact living adipose tissue that enabled us to simultaneously evaluate angiogenesis and adipogenesis in db/db mice. RESULTS—We found that adipocyte differentiation takes place within cell clusters (which we designated adipogenic/angiogenic cell clusters) that contain multiple cell types, including endothelial cells and stromal cells that express CD34 and CD68 and bind lectin. There were close spatial and temporal interrelationships between blood vessel formation and adipogenesis, and the sprouting of new blood vessels from preexisting vasculature was coupled to adipocyte differentiation. CD34 + CD68 + lectin-binding cells could clearly be distinguished from CD34 − CD68 + macrophages, which were scattered in the stroma and did not bind lectin. Adipogenic/angiogenic cell clusters can morphologically and immunohistochemically be distinguished from crown-like structures frequently seen in the late stages of adipose tissue obesity. Administration of anti–vascular endothelial growth factor (VEGF) antibodies inhibited not only angiogenesis but also the formation o