Berger, R

De Sain-Van der Velden, MGM

Kaysen, GA

Prinsen, BHCMT

Rabelink, TJ

Stellaard, F

Straver, HWHC

Van Rijn, HJM

The urinary loss of transferrin is sufficient to reduce plasma transferrin concentrations in the nephrotic syndrome. Hypotransferrinemia may lead to iron loss and microcytic anemia. The mechanism responsible for the hypotransferrinemia in the nephrotic syndrome is, however, unknown. In the present study, synthesis rate of transferrin was measured in vivo in nephrotic patients (n = 7) compared with control subjects (n = 6) using L-[1-C-13]-valine. Plasma transferrin and iron concentration in the patients were significantly lower than in control subjects (transferrin, 1.39 +/- 0.08 versus 2.57 +/- 0.11 g/L, P &lt;0.0001; iron, 10.2 +/- 0.8 versus 21.1 +/- 4.5 mol/L, P = 0.02). Furthermore, albuminuria correlated with transferrinuria (r(2) = 0.901, P = 0.001). The absolute synthesis rate of transferrin was increased in the patients (10.0 +/- 1.1 versus 7.4 +/- 0.7 mg/kg per d, P = 0.07), although this value failed to achieve significance. C-reactive protein, plasma iron, and proteinuria did not correlate with transferrin synthesis. In contrast, transferrin synthesis correlated with albumin synthesis (r(2) = 0.648, P = 0.03; n = 7). The present study indicates that increased transferrin synthesis occurs in nephrotic patients but is insufficient to compensate for urinary tosses. Because, overall, no significant relationship was found between transferrin synthesis and either C-reactive protein of iron, it is unlikely that inflammation suppresses or that iron deficiency stimulates increased transferrin synthesis in these patients. The correlation between transferrin synthesis and albumin synthesis suggests that transferrin synthesis is a component of a general response in hepatic protein synthesis in the nephrotic syndrome. This suggests that a therapeutic approach to maximize plasma transferrin concentrations in nephrotic patients should be aimed primarily at reducing urinary protein excretion.</p

ARTS repository - University of Groningen

Transferrin synthesis is increased in nephrotic patients insufficiently to replace urinary losses

Transferrin synthesis is increased in nephrotic patients insufficiently to replace urinary losses

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ARTS repository - University of Groningen