Sialic Acid Is a Predictor of Cardiovascular Complications in Renal Transplantation Recipients

Dr. Rafael Romero, Servicio de Nefrología, Hospital General de Galicia, Clínico Universitario, c/ Galeras s/n, E-15705 Santiago de Compostela (Spain) Fig. 1. SSA levels in the RTR group {W) and the control group (®). calculated creatinine clearance (r =-0.107) was found. More significant is the fact that 3 patients had an atherosclerotic vascular complication (1 stroke, 2 acute myocardial infarctions) 5-8 months after the study was done, and these 3 patients were in the 95th percen-tile of SSA level in the RTR group (SSA levels: 97, 97 and 105 mg/dl, respectively). Higher levels of SSA in RTR than in controls might be explained because of their lower renal function, but the lack of a clear correlation between SSA and creatinine or calculated creatinine clearance is against this hypothesis. We cannot exclude that SSA levDear Sir, Recently, Lindberg et al. [1] have identified a positive association between serum sialic acid (SSA) concentration and mortality from cardiovascular disease in a general population. Sialic acid is bound to the nonre-ducing end of carbohydrate chains of glyco-proteins and glycolipids. Some of these are called acute phase reactants and such substances rapidly increase in concentration after the onset of an inflammatory reaction or injury [2]. Although the cause of the association between SSA and mortality from cardiovascular disease is not known, a possible explanation of this fact is that SSA concentration may reflect the existence or the activity of an atherosclerotic process [1]. We have examined SSA concentration [3] in a group of 87 renal transplant recipients (RTR, 57 males, 30 females, age 40 ± 12.4, mean ± SD, years, time since transplantation more than 6 months, creatinine level 132 ± 59.2 μmol/l) treated with conventional therapy (prednisone, azathioprine and/or ci-closporin) and we have compared them with a group of 41 healthy subjects (29 males, 12 females, age 43 ± 13.8 years). SSA levels were higher in the RTR group in comparison with the control group (77 ± 10.5 mg/dl, range 55-105, versus 66 ± 9.3 mg/dl, range 44-81; p < 0.001, Mann-Whitney test), and