Apolipoproteins an Early and Better Diagnostic Marker for Diabetic Retinopathy
Dr. Geetha Rajagopalan,
Assistant Professor, Department of Biochemistry, Sri Lakshmi Narayana Institute of Medical Sciences, Puducherry-605502, India.
Introduction: Diabetic Retinopathy (DR) is one of the most common microvascular complications of diabetes and is the leading cause of blindness and visual impairment worldwide. Dyslipidemia is the major biochemical alteration in diabetes mellitus. Some studies have shown that traditional serum lipids are positively associated with the risk of DR whereas other studies have not consistently shown similar associations.
Aim: To compare the association of DR with the serum levels of Apo- A1, Apo B, Apo B/Apo-A1 ratio and with traditional lipid profile in Type 2 Diabetes Mellitus (T2D) patients.
Materials and Methods: The present study was a case-control study carried out with 100 T2D patients in ophthalmology department, Sri Lakshmi Narayana Institute of Medical Sciences, Puducherry from June 2016- December 2016. Fasting blood sugar and post-prandial blood sugar were estimated by GODPOD method and HbA1C by turbidimetric method. Serum lipid profile was assessed by autoanalyser. Serum Apo-A1 and Apo-B were measured using fully automated nephelometry. Apo-B/A1 ratio was calculated. Retinopathy was graded from the digital retinal photographs according to Early Treatment of Diabetic Retinopathy Study (ETDRS) criteria.
Results: Serum Apo-A1 was significantly decreased with severity of DR levels (p<0.001). Increasing levels of Apo B (p<0.001) and Apo B-to-Apo-A1 ratio (p<0.001) were found and strongly associated with severity of DR. HDL cholesterol levels were inversely associated with the severity of DR (p<0.05). Triglyceride level was significantly associated with the increased incidence and severity of DR in T2D patients and not LDL or total cholesterol.
Conclusion: There is strong association between serum apolipoproteins (Apo-A1, Apo B, and the ApoB/Apo-A1 ratio) and the progression and severity of DR in T2D patients than traditional lipids. Although apolipoprotein measurements have not been widely used in clinical practice, considering its protective mechanism further studies are needed to unravel the underlying mechanism in order to decrease the prevalence and to offer comprehensive eye care.