The Relationship Between The Liver Fat Content And Insulin Resistance

Obesity can induce the insulin resistance. Based on the fat gathering parts, obesity can be divides into two categories, abdominal obesity(visceral obesity, central obesity) that the fat is mainly accumulated in the abdominal cavity(including the parenchyma organ, omentum majus, the mesenterium) and the abdominal subcutaneous tissues, peripheral obesity(adiposis universalis) that the fat is mainly accumulated in subcutaneous tissue. Foreign studies suggested that intraperitoneal fat is significantly different from the abdominal subcutaneous fat in both the endocrine function and the morphology, and the two parts of the fat contributed on the insulin resistance are not the same, the intraperitoneal fat is much higher.A lot of epidemiological data show that, the intraperitoneal fat is relevant to the insulin resistance. But lots of clinical data showed that not all the fat people had the diabetes mellitus,. thus, compared with the fat mass, the fat distribution had more function on the insulin resistance. And the intraperitoneal fat distribution is different, it includes the fat accumulated in the parenchyma organ, omentum majus, the mesenterium. So how to assess the intraperitoneal fat accurately, it is important significance to the insulin resistance and type 2 diabetes mellitus.Nowadays, The main methods which is used in clinic analyzing visceral fat content quantitatively are bioelectrical impedance analysis (BIA), Dual Energy X-ray Absorptiometry(DEXA), supersonic inspection, Computer Tomography(CT), Magnetic Resonance Imaging(MRI), spectral analysis and so on. But all of those cannot measure single organ quantitatively. The method of bioelectrical impedance analysis (BIA) cannot be used to measure the local fat content, and in the actual operating process, it is easily affected by the shifting of our body weight. The method of the dual-energy X-ray absorptiometry—(DEXA) has the poor repeatability. The ultrasonic method is simple, low cost, high repeatability and no radiation, but it also has several defects, for example, the probe cannot bear the high press and so on. The CT equipment is more advanced, but the scanning images are not very clear, then the measuring results cannot be correct all the time, and the measuring process is radiant.In recent years, MRI water-fat separation method is considered as a new fat-measuring technique, compared with BIA method, DEXA method and CT equipment, it has several advantages as follows:(1) simple operation, scanning in the same sequence, high repeatability (2) the scanning images are very clear, especially in the local regions, it is the best and the fist choice for the purpose of high definition(3) using the automatic analysis technique (4) the whole measuring process is in a high magnetic field, it is no harm to human body.Aim:By the MRI fat separation technique(3.0T superconducting high-field) and the bioelectrical impedance analysis(BIA) equipment Inbody 720, we assess the human liver fat content and the fat mass, then we further assess the relationship between the liver fat content and insulin resistance (IR) adding the serological testing.Methods:We enrolled 50 adults who is willing to attend the research in Jinan from September 2010 to March 2011, we excluded the people of DM or family history, those who had the diseases of liver, pancreas and kidney, those who had the autoimmune disease, those who had the drug and drinking-wine addiction, and those who was pregnancy.1. Measuring the liver fat content through the MRI water-fat separation technique(3.0T superconducting high-field).2. Measuring the body composition through the bioelectrical impedance analysis (BIA) equipment Inbody 720.3. Serological testing, including the fasting glucose, fasting insulin, fasting FFA and so on.Results:1. The average liver fat content of the 50 volunteers is (5.66±5.03)%, and 35 subjects(24 male and 11 female) had <5.6%,15 subjects(15 male) had >5.6%.2. BMI, WC, H, WHR, VFA and obesity degree are positive correlation to the liver fat content(LFC) remarkably, the order is WC>BMI>VFA>obesity degree >body fat>WHR>H>height, and the age is irrelevant to the LFC.3. LFC, BMI, WC, H, WHR and obesity degree are positive correlation to HOMA-IR remarkably (P<0.01), the height and the body fat are correlation to HOMA-IR(P<0.05), and the order is LFC> WC> WHR> H> BMI>obesity degree. The age is irrelevant to the HOMA-IR.4. Compared with the lower LFC, the higher LFC has the tall HOMA-IR, the fasting insulin and the glycerin trilaurate level are higher, the HDL lever is decreased, and the fasting glucose and fasting FFA are not influenced.Conclusion:1. Through the measurement of the liver content and serological testing, we find the height, BMI, fat mass, WC, H, WHR and VFA are positive correlation to the liver fat content(LFC) remarkably, and the serological testing(AST,GGT,fasting FFA,fasting glucose and fasting insulin level) are also positive correlation to the liver fat content(LFC) remarkably, and the HDL level is negative correlation to the liver fat content.2. From the standpoint of MRI, LFC is positive correlation to HOMA-IR, and when the liver fat content increased, the HOMA-IR, the fasting insulin and glycerin trilaurate level will corresponding increased, but the protecting factor HDL level is decreased, then further approve the ectopic fat deposition theory.