Cholesterols, Apolipoproteins, and Their Associations with the Presence and Severity of Diabetic Retinopathy: A Systematic Review

Abstract

Serum apolipoproteins have been reported as a more significant marker for diabetic retinopathy (DR) compared with serum cholesterols. This article aims to review the associations between serum cholesterols and apolipoproteins, and the presence and severity of DR. The protocol of this systematic review was registered at the PROSPERO registry (CRD42022303331). We conducted a systematic search of literature published between 2011 to 2022 using the search terms “serum cholesterol” AND/OR “lipoprotein” AND/OR “apolipoprotein” AND/OR “diabetic retinopathy”. Fifteen studies were included in this review. Six studies assessed the association between serum cholesterols, apolipoproteins, and the presence of DR. Three studies reported lower levels of apolipoprotein A1, and one study reported higher levels of apolipoprotein B in patients with DR. The remaining nine studies compared serum cholesterol and apolipoprotein levels according to DR severity. Patients with more severe grades of DR presented with lower apolipoprotein A1 in six (66.7%) studies, higher apolipoprotein B levels in seven (77.8%) studies, and a higher apolipoprotein B/apolipoprotein A1 ratio in six out of seven (85%) studies. In conclusion, serum apolipoproteins, in particular the apolipoprotein B/apolipoprotein A1 ratio, were a more consistent marker for DR severity compared with serum cholesterols.

The Predictors of Early Treatment Effectiveness of Intravitreal Bevacizumab Application in Patients with Diabetic Macular Edema

“…Several apolipoproteins, including ApoA-I, apolipoprotein C3, ApoB, and apolipoprotein A5, are associated with lipid metabolism and are found in serum lipoprotein complexes. These apolipoproteins have been linked to the development and progression of DR [33]. In contrast to individuals without diabetes, patients with diabetes exhibited elevated ApoA-I expression within the retinal pigment epithelium [34].…”

“…In contrast, ApoB has been shown to have a positive correlation with the severity of DR [36,37]. In a systematic review, Soedarman et al concluded that apolipoprotein parameters are associated with the presence of DR, especially with more severe stages of DR, and that the ApoB/ApoA-I ratio is a more accurate predictor of DR severity than either ApoB or ApoA-I alone [33]. Analyzing the ApoB/ApoA-I ratio yielded more consistent findings than interpreting ApoA-I and ApoB results separately [8,36].…”

Effect of Lipids on Diabetic Retinopathy in a Large Cohort of Diabetic Patients after 10 Years of Follow-Up

“…Evaluating lipid indices is a relatively recent development in the study of patients with cardiovascular risk, since LDL-C values have exclusively turned out to not be optimal for assessing risk-especially in patients at intermediate risk [18]. The Framingham Heart Study and the Coronary Primary Prevention Trial [19] demonstrated that the TC/HDL-C and LDL-C/HDL-C indices are good predictors of cardiovascular disease-especially in cases of hypertriglyceridemia, in which it is preferable to use the values of TC/HDL-C.…”

Circulating Biomarkers to Predict Diabetic Retinopathy in Patients with Diabetic Kidney Disease

“…While Apo-A1, as a component of the HDL protein, possesses anti-oxidant and anti-inflammatory properties, Apo-B is the main apolipoprotein of LDL, and in contrast, exerts atherogenic effects in the retinal vessels [ 26 ]. Elevated Apo-A1 and low Apo-B levels have been shown to be protective factors of DR, and an increased Apo-B/Apo-A1 ratio was associated with a more severe form of DR [ 27 ]. Zhang et al [ 28 ].…”