Study: Nerve growth factor concentrations may help evaluate diabetic retinopathy status

Nerve growth factor concentrations may be useful for assessing diabetic retinopathy status, according to a study by researchers in South Korea. Additionally, because serum and tear nerve growth factor concentrations appear to share a strong correlation, tear fluid assays may be an “effective, accurate and noninvasive option” for measuring nerve growth factor, the authors said.

Kyoung Soo Park, MD, and colleagues evaluated demographic data and diabetic parameters for 254 patients with diabetic retinopathy (DR) who were compared against 71 nondiabetic controls. Specifically, the researchers assessed serum and tear nerve growth factor concentrations and the proportion of nerve growth factor to total protein in serum and tear fluid.

The researchers reported that serum and tear nerve growth factor levels were higher in patients with proliferative DR (98.7 ng/mL in serum; 45.6 ng/mL in tear) than in nondiabetic controls (18.5 ng/mL in serum; 8.3 ng/mL in tear). Additionally, serum and tear nerve growth factor levels were higher in patients with proliferative DR than in patients with nonproliferative DR (26.6 ng/mL in serum and 8.6 ng/mL in tear; P < .001 for both serum and tear differences), according to the study.

Similarly, after adjusting for age, gender, serum blood urea nitrogen, creatinine and diabetic parameters, the researchers reported higher nerve growth factor levels in patients with proliferative DR than in both controls and patients with nonproliferative DR.

The proportion of nerve growth factor to total protein for both serum and tear fluid was also higher in patients with proliferative DR than in controls and patients with nonproliferative DR, the authors noted.

“[Nerve growth factor] levels correlated well with diabetes duration, HbA1c, and blood sugar levels and diabetic nephropathy,” they said.

The study is published in the March issue of American Journal of Ophthalmology.