Study of urinary transferrin and iron excretion in insulin dependent diabetes mellitus [IDDM] with variable degrees of albuminuria

ABSTRACT

This study included 60 insulin dependent diabetic male patients in 3 groups according to urinary albumin excretion. Group I with normal albuminuria [urine albumin < 30 mg/day], group II with microalbuminuria [urine albumin 30-300 mg/day] and group III with macroalbuminuria [urine albumin > 300 mg/day]. Each diabetic group included 20 cases and these groups were compared with control group comprised of 20 healthy subjects. The present work was undertaken to study urinary transferrin and iron in diabetic patients with varying amounts of albuminuria. The following were the results of this work -There was significant increase [P < 0.05] in urinary transferrin and iron in all the studied diabetic groups compared to the normal controls, and this increase occurrs early in the course of the diabetic renal disease. -The iron/transferrin ratio in urine was much higher than that in serum in all the diabetic groups. This means that iron is present in the urine in marked excess than its carrier transferrin. -There was significant positive correlation [P < 0.05] between urinary albumin and urinary transferrin in both the micro and macro albuminuric diabetic groups. -There was significant positive correlation [P < 0.05] between urinary albumin and urinary iron in all the diabetic groups. -There was significant positive correlation [P< 0.05] between urinary iron and urinary transferrin in the macroalbuminuric diabetic group. From this work we can conclude the following -Transferrin which has the similar molecular size as albumin, its urinary excretion in excess as well as the excess excretion of urinary iron in diabetics may suggest the possibility of development of glomerular disease and nephropathy. -Urinary iron excretion is increased early in the course of diabetic renal disease. The fact that iron is present in the urine in marked excess of transferrin further suggests that either iron is dissociated from transferrin in the tubule fluid with transferrin being reabsorped, or that iron is added to the tubule fluid by means other than filtration without transferrin. This finding suggests that iron could be present in tubule fluid in a form which would catalyze the Haber- Weiss reaction with the formation of free radicals resulting in tubulointerstial injury. -The increase of urinary iron excretion in diabetics may reduce iron stores making the individuals more at risk of developing iron deficiency if there are other causes of iron or blood loss. We recommended detection of urinary transferrin and iron in IDDM patients as their excretion in excess may suggest the possibility of development of glomerular disease and nephropathy which may need further investigations and follow up for proper management of this risky diabetic complication