Free fatty acid can induce cardiac dysfunction and alter insulin signaling pathways in the heart

• Published in: Lipids in health and disease 2018-08, Vol.17 (1), p.185-185, Article 185
• Main Authors: Han, Lina, Liu, Jiali, Zhu, Leilei, Tan, Fang, Qin, Yupei, Huang, He, Yu, Yerong
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; AMP; Cardiac dysfunction; Causes of; Complications and side effects; Congestive heart failure; Development and progression; Echocardiography; Fatty acids; Free fatty acids; Genetic aspects; Glucose; Glucose transporter; Glycerol; Heart failure; Heparin; Hyperinsulinemia; Insulin resistance; Kinases; Myocardium; Nitric oxide; Nitric-oxide synthase; Physiological aspects; Protein transport; Protein-serine/threonine kinase; Risk factors; Rodents; Signal transduction; Structure-function relationships; Western blotting
• ISSN: 1476-511X; 1476-511X
• DOI: 10.1186/s12944-018-0834-1

Insulin resistance has been independently related to heart failure. However, the specific mechanisms of high FFA levels in the pathophysiology of heart failure in insulin-resistant states are remain largely unclear. This study investigated whether elevated circulating free fatty acids (FFA) levels result in impaired cardiac structure and function in vivo via insulin-related signaling pathways in myocardium. Male Wistar rats were randomly divided into the intralipid group (20% intralipid plus heparin infusion) and the control group (glycerol infusion). Blood samples were collected before and after 6-, 12-, and 24-h infusions. Cardiac structure and function were measured using echocardiography. Maximum velocity of myocardial contraction (+dP/dt ) and diastole (-dP/dt ) were measured using a physiological polygraph in vivo. Heart tissues were collected for western blotting. Compared with the control group, plasma FFA, plasma glucose, and serum insulin levels increased significantly in the intralipid group. With increasing infusion time, cardiac function in the intralipid group decreased gradually compared with the control group. After a 24-h infusion, early (E', cm/s) diastolic peak velocities and (-dP/dt ) decreased significantly. Protein expression of phosphatidylinositol 3-kinase (PI3K), the serine/threonine kinase Akt, and phosphorylated Akt in myocardium increased after a 6-h infusion and decreased significantly after a 24-h infusion in the intralipid group. Protein expression of glucose transporter type 4 (GLUT4), Adenosine 5'-monophosphate -activated protein kinase (AMPK), phosphorylated AMPK(p-AMPK), and endothelial nitric oxide synthase (eNOS) in myocardium gradually decreased in the intralipid group. Elevated FFA levels may impair cardiac function and cardiac dysfunction might result from myocardial insulin resistance with significant changes to PI3K-Akt-GLUT4 and AMPK-eNOS signaling pathways with increasing FFA levels.