Annett Hoffmann1, Thomas Ebert2, Nora Klöting3, Janine Dokas4, Franziska Jeromin4, Beate Jessnitzer1, Ralph Burkhardt4, Mathias Fasshauer2, Susan Kralisch5. 1. University of Leipzig, Department of Endocrinology and Nephrology, 04103 Leipzig, Germany. 2. University of Leipzig, Department of Endocrinology and Nephrology, 04103 Leipzig, Germany; Leipzig University Medical Center, IFB AdiposityDiseases, 04103 Leipzig, Germany. 3. Leipzig University Medical Center, IFB AdiposityDiseases, 04103 Leipzig, Germany. 4. University of Leipzig, Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, 04103 Leipzig, Germany. 5. University of Leipzig, Department of Endocrinology and Nephrology, 04103 Leipzig, Germany; Leipzig University Medical Center, IFB AdiposityDiseases, 04103 Leipzig, Germany. Electronic address: susan.kralisch@medizin.uni-leipzig.de.
Abstract
OBJECTIVES: Conflicting evidence concerning leptin in atherosclerosis has been published. Furthermore, dose-dependent effects of leptin on atherogenesis have not been studied. METHODS: Leptin-deficient low-density lipoprotein receptor (LDLR) knockout (LDLR(-/-);ob/ob) mice were treated with saline, 0.1, 0.5, or 3.0mg/kg body weight (BW)/d recombinant leptin over 12weeks starting at 8weeks of age. Aortic root and brachiocephalic artery (BCA) atherosclerotic lesions were analyzed by oil red O staining. Furthermore, glucose homeostasis, lipid metabolism, and liver function including tissue studies were assessed in all animals. RESULTS: Leptin treatment dose-dependently decreased BW in LDLR(-/-);ob/ob mice as compared to saline. Mice in the 0.1 and 0.5mg/kgBW/d groups remained heavier (i.e. subphysiological leptin dose) and in the 3.0mg/kgBW/d group had similar weight (i.e. physiological leptin dose) as compared to non-leptin-deficient LDLR(-/-) animals. Recombinant leptin dose-dependently reduced plaque area in the aortic root and the BCA by 36% and 58%, respectively. Leptin-mediated reductions of plasma total and LDL-cholesterol (Chol) remained independent predictors for aortic root plaque area. Chol content in liver, as well as hepatic expression of key lipid and proinflammatory genes, were dose-dependently regulated by leptin. Furthermore, leptin treatment increased circulating levels and adipose tissue mRNA expression of the adipokine adiponectin. CONCLUSIONS: Leptin administration within the subphysiological to physiological range diminishes atherosclerotic lesions. Leptin appears to mediate its antiatherogenic effects indirectly through reduction of hypercholesterolemia and liver steatosis, as well as upregulation of insulin-sensitizing and atheroprotective adiponectin.
OBJECTIVES: Conflicting evidence concerning leptin in atherosclerosis has been published. Furthermore, dose-dependent effects of leptin on atherogenesis have not been studied. METHODS:Leptin-deficient low-density lipoprotein receptor (LDLR) knockout (LDLR(-/-);ob/ob) mice were treated with saline, 0.1, 0.5, or 3.0mg/kg body weight (BW)/d recombinant leptin over 12weeks starting at 8weeks of age. Aortic root and brachiocephalic artery (BCA) atherosclerotic lesions were analyzed by oil red O staining. Furthermore, glucose homeostasis, lipid metabolism, and liver function including tissue studies were assessed in all animals. RESULTS:Leptin treatment dose-dependently decreased BW in LDLR(-/-);ob/ob mice as compared to saline. Mice in the 0.1 and 0.5mg/kgBW/d groups remained heavier (i.e. subphysiological leptin dose) and in the 3.0mg/kgBW/d group had similar weight (i.e. physiological leptin dose) as compared to non-leptin-deficient LDLR(-/-) animals. Recombinant leptin dose-dependently reduced plaque area in the aortic root and the BCA by 36% and 58%, respectively. Leptin-mediated reductions of plasma total and LDL-cholesterol (Chol) remained independent predictors for aortic root plaque area. Chol content in liver, as well as hepatic expression of key lipid and proinflammatory genes, were dose-dependently regulated by leptin. Furthermore, leptin treatment increased circulating levels and adipose tissue mRNA expression of the adipokine adiponectin. CONCLUSIONS:Leptin administration within the subphysiological to physiological range diminishes atherosclerotic lesions. Leptin appears to mediate its antiatherogenic effects indirectly through reduction of hypercholesterolemia and liver steatosis, as well as upregulation of insulin-sensitizing and atheroprotective adiponectin.