Clinical Study On The Relationship Between Serum Retinol Binding Protein 4 And Type 2 Diabetic Retinopathy

Background and Objective With the improvement of the human living standard and the acceleration of aging,the number of patients with type 2 diabetes(T2DM)is increasing year by year.Diabetic retinopathy(DR)is the main complication of T2 DM,and it is the main cause of visual impairment and preventable blindness.About 1/3 of diabetic patients suffer from DR,while 1/3 DR patients suffer from vision-threatening diabetic retinopathy(VTDR)which includes diabetic macular edema(DME)and proliferative DR(PDR).Long term hyperglycemia is the main cause of DR.The control of blood glucos can effectively reduce the occurrence and development of DR,but it does not completely prevent DR.The pathogenesis of DR is not yet clear.In addition to long-term hyperglycemia,many factors are also involved in the development of DR.Retinol binding protein 4(RBP4)is a new adipocytokine,which is associated with obesity,insulin resistance,cardiovascular disease and T2 D microvascular complications.The serum RBP4 is mainly synthesized from the liver.RBP4 and vitamin A,transthyretin(TTR)combined with a ternary complex,involved in the transport of vitamin A.Recent studies have found that RBP4 is also secreted by adipocytes and is involved in insulin resistance,which has attracted many scholars' attention to the new serum RBP4.In addition,two clinical studies found that compared with patients with mild retinopathy or non DR diabetes,the level of serum RBP4 increased in proliferative diabetic retinopathy(PDR).The full field electroretinogram(F-ERG)can record the electrophysiological activity of the whole retinal neurons.B wave mainly reflects the function of bipolar cells in the inner retina,and its amplitude can be used to evaluate the early degree of DR.In view of the fact that the pathogenesis of serum RBP4 in DR is not clear at present,we intend to explore the significance of serum RBP4 to the pathogenesis of DR by measuring the serum RBP4 concentration and b wave amplitude of DR,so as to provide evidence for early prevention and treatment of DR.Methods Object:All cases were from October 2015 to October 2016.There were 83 cases of T2 DM in Henan Province People's Hospital,including 44 males and 39 females,ranging in age from 37 to 73 years old,with an average age of 55.7 years.Grouping:According to the severity of DR,all the collection objects are divided into three groups: no diabetic retinopathy group(group NDR),non proliferative diabetic retinopathy group(group NPDR)and proliferative diabetic retinopathy group(group PDR).The NPDR group included microaneurysms,small bleeding;bleeding spots,hard exudates,white cotton wool spots,bleeding spots;while group PDR included angiogenesis,vitreous hemorrhage;fiber hyperplasia;concurrent tractional retinal detachment.Measurements: We used SIEMENS biochemical line to measure the following biochemical indicators: retinol binding protein 4,glycosylated hemoglobin(Hb A1c),low density lipoprotein(LDL-C),high-density lipoprotein(HDL-C),total cholesterol(TC),triglyceride(TG)and so on.The data of blood pressure,height,weight,and the course of diabetes were collected.We detected the electrophysiological activity of patients with Rowland multifocal visual electrophysiology instrument and collected the b wave amplitude of F-ERG when the stimulation intensity was 3.0 cd · s / m2.Statistical treatment: The data were statistically processed with SPSS22.0 statistics software.All measurement data were expressed with mean±standard deviation(x±s).The measurement data between group NDR,NPDR group and PDR group were compared by single factor analysis of variance.The sex composition of group NDR,group NPDR and group PDR was compared with chi square test.The Pearson test was used to analyze the relationship between RBP4 and various factors.The difference was statistically significant with P < 0.05.Results1.Among all 83 subjects,32(38.55%)were in group PDR,20 in group NPDR(24.1%),and 31 in group NDR(37.35%).The three group of RBP4[(56.729.82)mg/L vs(46.906.86)mg/L vs(41.689.15)mg/L,P < 0.05],ERG[(172.3736.47)?V vs(287.1536.15)?V vs(369.6867.96)?V,P < 0.05],duration of diabetes mellitus[(13.565.59)years vs(9.54.96)vs years(2.031.49)years.P < 0.05] had significant difference(P < 0.05).2.Simple correlation analysis showed that serum RBP4 was negatively associated with ERG(r=-0.458,p=0.000),positively correlated with Hb A1c(r=0.302,p=0.006),positively correlated with TCH(r=0.332,p=0.002),positively correlated with LDL-C(r=0.252,p=0.022),positively correlated with age(r=0.270,p= 0.014),positively correlated with the course of diabetes into(r=0.409,p=0.000).Conclusion The level of serum RBP4 is closely related to the occurrence and development of DR.The increase of its level may be a clinical marker for the progression of DR in T2 DM patients.We speculate that besides the insulin resistance,serum RBP4 may also cause the occurrence and development of DR through the mechanism of neuroinflammation.