en Medical Biology Medical Biology مقاله پژوهشی Original Research Article <p style="text-align: justify;"><span style="font-size:16px;"><span style="font-family:Times New Roman;"><span style="color:#ffffff;"><strong><span style="background-color:#008080;">Background & Objective:</span></strong></span><em> </em>Diabetic retinopathy (DR) is a common microvascular complication of type 2 diabetes mellitus (T2DM) and the leading cause of vision loss in working-age adults. Vitamin A (retinol) has a role in the mechanism of vision process and retinol binding protein-4 (RBP4), is a carrier of vitamin A, and as an adipokine may be associated with increased risk for insulin resistance and DR. This case-control study was aimed to determine and analyze plasma RBP4-to-vitamin A ratio in relation with terms of DR severity.<span dir="RTL"></span><br> <span style="color:#ffffff;"><strong><span style="background-color:#008080;">Materials & Methods:</span></strong></span> In the present analytical cross-sectional study, 51 T2DM patients, aged 48-73 years old, were enrolled from those attending to the Ophthalmology Center of Vali-e Asr Hospital, Zanjan, Iran. Patients were categorized as non-retinopathy diabetic patients (NRDP) without any eye problem, those with mild non-proliferative DR (mild NPDR) (n=12), those with severe non-proliferative diabetic retinopathy (severe NPDR) (n=12), and those with proliferative DR (PDR) (n=12); a control group (n=15) was also considered. Anthropometric parameters, BMI, and WHR were determined and blood sample weas taken from each participant after overnight fasting (12-14h) to measure their biochemical parameters. Serum RBP4 and vitamin A levels were measured via ELISA and C18 reverse-phase HPLC methods, respectively.<br> <span style="color:#ffffff;"><strong><span style="background-color:#008080;">Results:</span></strong></span> Plasma RBP4 concentration was significantly higher in three different stages of DR than that of the control group suffering from diabetes (77.0&plusmn;11.0, 81.7&plusmn;10.9 and 88.3&plusmn;11.9 vs. 71.4&plusmn;12.3, respectively; <em>P</em>=0.004). The ratio of plasma RBP4-to-retinol in DR groups was found to be significantly higher than that in the control group suffering from diabetes (0.21&plusmn;0.06, 0.27&plusmn;0.12 and 0.28&plusmn;0.07 vs. 0.16&plusmn;0.14, respectively; <em>P</em>=0.001).<span dir="RTL"></span><br> <span style="color:#ffffff;"><strong><span style="background-color:#008080;">Conclusion:</span></strong></span> Higher plasma RBP4-to-vitamin A ratio was related to DR severity. Further experimental studies with larger scales are recommended.</span></span></p> Diabetic retinopathy, RBP4, RBP4 delivery kinetic, Vitamin A 175 182 http://journal.zums.ac.ir/browse.php?a_code=A-10-123-3&slc_lang=en&sid=1 Hadi Rostamkhani hadirostamkhan@gmail.com 5200319475328460052609 5200319475328460052609 No Zanjan Metabolic Diseases Research Center, Zanjan University of Medical Sciences, Zanjan, Iran Arezo Karimimoghaddam arezookarimimoghaddam@yahoo.com 5200319475328460052610 5200319475328460052610 No Zanjan Metabolic Diseases Research Center, Zanjan University of Medical Sciences, Zanjan, Iran Jalal Hejazi jalal hejazi@yahoo.co.uk 5200319475328460052611 5200319475328460052611 No Zanjan Metabolic Diseases Research Center, Zanjan University of Medical Sciences, Zanjan, Iran Hossein Chiti chiti@zums.ac.ir 5200319475328460052612 5200319475328460052612 No Zanjan Metabolic Diseases Research Center, Zanjan University of Medical Sciences, Zanjan, Iran Ali Awsat Mellati mellati@zums.ac.ir 5200319475328460052613 5200319475328460052613 Yes Zanjan Metabolic Diseases Research Center, Zanjan University of Medical Sciences, Zanjan, Iran