Reduced Serum Endostatin in Premenopausal Women with Lipedema Suggests Altered Vascular Homeostasis

Background: Lipedema is a chronic disorder that predominantly affects women and is characterized by abnormal subcutaneous adipose tissue accumulation, pain, and vascular dysfunction. However, reliable circulating biomarkers that reflect disease-specific pathophysiology are still lacking. This study investigated serum markers associated with adipose tissue, inflammation, and angiogenesis to further elucidate the pathophysiology of lipedema. Methods: In this cross-sectional observational study, fasting serum levels of adiponectin, chemerin, lipopolysaccharide-binding protein (LBP), proprotein convertase subtilisin/kexin type 9 (PCSK9), soluble CD163 (sCD163), and soluble CD137 (sCD137)—proteins associated with obesity and inflammation—were measured in 23 premenopausal women with lipedema and 23 age-matched healthy premenopausal controls. Serum endostatin levels, an angiogenesis inhibitor, and insulin-like growth factor binding protein 2 (IGFBP2), a potent proangiogenic factor, were also assessed. Results: Patients with lipedema and obese controls had comparable body mass index, glucose, and serum lipid profiles. No significant differences were observed between groups in circulating levels of adiponectin, chemerin, LBP, PCSK9, sCD163, sCD137 and IGFBP2. In contrast, serum endostatin levels were significantly reduced in patients with lipedema (p = 0.038). Additional analyses demonstrated markedly higher endostatin expression in human subcutaneous adipose tissue than in the liver, suggesting that circulating endostatin levels may be related to adipose tissue mass. However, serum endostatin levels were lower in obese compared with normal-weight women (p < 0.001). Conclusion: Lipedema was not associated with altered circulating levels of adiponectin, chemerin, LBP, PCSK9, sCD163, sCD137 or IGFBP2. Reduced serum endostatin levels support a potential role for vascular dysfunction in the pathophysiology of lipedema.