Diabetic retinopathy (DR) is a major microvascular complication of type 2 diabetes mellitus (T2DM), with oxidative stress and micronutrient imbalance potentially leading to disease progression beyond glycemic control. A study published in Diabetology evaluated serum trace element levels and antioxidant enzyme activities in patients with T2DM with and without DR, and assessed their relationship with DR severity.

The study included 61 patients with T2DM and 27 healthy controls. Patients with T2DM were categorized into groups without DR (n=30) and with DR (n=31), while the DR group was further divided into non-proliferative DR (NPDR; n=19) and proliferative DR (PDR; n=12). Serum trace elements, including copper (Cu), zinc (Zn), iron (Fe), magnesium (Mg), chromium (Cr), manganese (Mn), cadmium (Cd), and selenium (Se), were measured using inductively coupled plasma-mass spectrometry. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were assessed using colorimetric assays.

Findings

• Significant differences in trace element levels and antioxidant enzyme activities were observed across study groups (P < 0.001 to 0.05).
• The DR group showed lower Cr, Cu, and Se levels compared with patients with T2DM without DR.
• Cd, Zn, and Mn levels were higher in patients with DR than in those without DR.
• Fe levels were significantly higher in the PDR subgroup than in the T2DM without DR group (P < 0.001).
• Compared with NPDR, the PDR subgroup demonstrated greater reductions in Cr, Cu, and GSH-Px, along with higher Mn, Fe, and Zn levels (P < 0.001).
• Several biomarkers remained significantly associated with DR after metabolic adjustment, and significant correlations were observed between trace elements and antioxidant enzymes. 

The analysis demonstrated distinct trace element and antioxidant enzyme patterns across DR severity stages in T2DM. These findings indicate that oxidative stress and micronutrient imbalance may contribute to biochemical alterations observed in DR progression.