Letters and Replies Combined Treatment with Renin-angiotensin System Blockers and Polyunsaturated Fatty Acids

Sir, We have read with interest the paper concerning the antiproteinuric effect of polyunsaturated fatty acid (PUFA) in IgA patients [1]. The authors mentioned that the evaluation of effectiveness of PUFA in IgA therapy gave conflicting results. Their results suggested that the hypoalbuminuric effect of PUFA was detected in the patients on ACEi/ARB therapy in which a haemodynamic-dependent factor of albuminuria was already offset. However, the haemodynamic-related beneficial effect of PUFA on albumin excretion could not be excluded in the face of our previous study in IgA patients [2]. In this study, patients were given PUFA for 12 months in a dose three times smaller than used in the patients of Ferraro et al. [1]. We also observed that the fall in protein excretion was associated with improvement of intrarenal haemodynamics, estimated as a response of GFR to dopamine infusion [2]. We therefore can speculate that long-term therapy of IgA patients with PUFA may delay the progression of renal disease via improvement of intrarenal blood flow and that was associated with a fall of NAG excretion [2]. Our findings are complementary to the paper of Ferraro et al. showing that treatment with PUFA may either reduce albuminuria or improve renal blood flow also in patients with a preserved renin–angiotensin– aldosterone system. But neither Ferrano’s study nor our study could preclude to what extend the beneficial effect of PUFA was related to improvement in the balance between vasodilator/vasoconstrictor mediators or activation of an anti-inflammatory response. Ferraro et al. revealed that the antiproteinuric effect of PUFA was more prominent in patients with more haematuria. This may impute that the effectiveness of the therapy with PUFA is determined rather by activity of the disease per se than by concomitant therapy.