Background: Sialic acid is released from terminal oligosaccharide chain of some proteins of the acute phase (fibrinogen, orosomucoid, haptoglobin, etc.). Its serum concentrations have been commonly increased during acute inflammation. Its relation diabetes mellitus or late complications of the disease have been recently studied as well. The aim of our investigation was to determine serum concentrations of sialic acid in patients with diabetes mellitus Type 1 in relation to presence or absence of late diabetic complications.
Methods and results: The authors examined a group of 62 patients treated for diabetes mellitus Type 1, mean age 28.7 +/- 9.8 years, having been treated for this disease for 11.8 +/- 8.7 years on the average. The mean level of glycated hemoglobin HbAlc was 9.08 +/- 1.84%. In 21 patients there were signs of diabetic nephropathy, seven of them already suffering from proteinuria. Retinopathy already developed in 12 patients. The mean concentration of sialic acid in the whole cohort was 1.916 +/- 0.292 mmol/litre. The correlation of serum sialic acid with age, duration of diabetes and glycated hemoglobin was not statistically significant. There was no significant difference between the serum concentration of sialic acid in patients without apparent nephropathy and those who were affected by nephropathy, or the subgroup with proteinuria (1.945 +/- 0.328 against 1.914 +/- 0.302 mmol/litre and 1.943 +/- 0.328 mmol/litre, respectively). Statistically significantly higher concentrations of serum sialic acid were found in the subgroup of patients with present retinopathy (2.085 +/- 0.244 mmol/litre against 1.890 +/- 0.270 mmol/litre, P < 0.018).
Conclusions: Our findings are in agreement with the previously proved increased concentration of proteins of the acute phase in diabetic patients and correspond well to the previously proved finding of elevated serum concentration of sialic acid in diabetic patients of Type 2 with retinopathy against other patients. It may not be excluded that the serum sialic acid could be used as a marked of the risk of late complications of diabetes mellitus.