1698-P: Obesity-Induced Increase in Cystatin C Alleviates Tissue Inflammation and Hepatic Insulin Resistance

Removal of one kidney (uninephrectomy; UniNx) in mice reduced high fat-diet (HFD)-induced adipose tissue inflammation thereby improving adipose tissue and hepatic insulin sensitivity. Such finding was accompanied by increased circulating cystatin C levels in UniNx compared to sham-operated mice. Importantly, cystatin C may have anti-inflammatory properties, and circulating cystatin C levels were reported to positively correlate with obesity as well as type 2 diabetes. However, the causal relationship of such correlation remains unclear. Herein, HFD feeding of cystatin C-deficient (CysC KO) mice aggravated obesity-associated adipose tissue dysfunction and inflammation, as reflected by an accumulation of pro-inflammatory monocytes and elevated expression of pro-inflammatory mediators. Moreover, markers of adipocyte differentiation were decreased. Similarly to findings in adipose tissue, expression of pro-inflammatory cytokines was increased in liver and skeletal muscle of HFD-fed CysC KO mice. In line, HFD-induced hepatic insulin resistance and impairment of glucose tolerance were further aggravated in knockout mice. Consistently, chow-fed CysC KO mice were more susceptible to lipopolysaccharide (LPS)-induced adipose tissue inflammation. In people with obesity, circulating cystatin C levels correlated negatively with mRNA expression of pro-inflammatory cytokines such as Hif1α as well as IL-6. Moreover, healthy (i.e., insulin-sensitive) subjects with obesity depicted significantly higher mRNA expression of cystatin C in subcutaneous white adipose tissue. In conclusion, cystatin C is upregulated under obesity conditions and thereby counteracts inflammation of peripheral insulin-sensitive tissues and, thus, obesity-associated deterioration of glucose metabolism. Disclosure M.A. Dedual: None. S. Wueest: None. T. Challa: None. F. Lucchini: None. T. Aeppli: None. M. Borsigova: None. A.A. Mauracher: None. S. Vavassori: None. J. Pachlopnik Schmid: Advisory Panel; Self; Novartis AG, Swedish Orphan Biovitrum. M. Blüher: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk A/S, Sanofi. Speaker’s Bureau; Self; Amgen, Novartis AG. D. Konrad: Research Support; Self; Novo Nordisk A/S. Funding Children’s Research Centre; University Children’s Hospital Zurich; University of Zurich (FK-18-027); Swiss National Science Foundation (310030-160129, 10030-179344); Wolfermann-Nägeli Foundation