REVIEW ARTICLE Fatty Acids in Nephrotic Syndrome and Chronic Kidney Disease Stefano Turolo, BD,* Alberto Edefonti, MD,* Marie Louise Syren, MSc,† Franca Marangoni, PhD,‡ William Morello, MD,* Carlo Agostoni, MD, PhD,† and Giovanni Montini, MD, PhD* , † The role of fatty acids (FAs) in inflammation and in the related chronic diseases has been demonstrated. However, there is a lack of consistent and agreed knowledge about the role of FA profile and renal physiology and pathology, most articles focusing on the effect of polyunsaturated FAs supplementation, without considering the impact of basal FA metabolism on the efficacy of the supplementation. Here, we have summarized the specific literature concerning the assessment of circulating FA in 2 renal diseases, namely nephrotic syn- drome and chronic kidney disease, also under hemodialytic treatment, and have received the most significant contributions in the last years. The effects of changes of FA profile and metabolism and the possible involvement of polyunsaturated FA metabolites in raising and modulating inflammation are discussed. Ó 2017 by the National Kidney Foundation, Inc. All rights reserved. Introduction A LTHOUGH FATTYACIDS (FAs) play a clear role in chronic degenerative diseases with an inflammatory component in most organs and systems, 1 their role in the pathogenesis of diseases involving kidney is less evident. 2 As a matter of fact, scarce and scant data are available in this field, possibly explaining why the response to FA sup- plementation in renal diseases is not univocal. Recent literature regarding FA and kidney disorders has mainly focused on FA ability to prevent kidney damage or to ameliorate kidney function in renal diseases than on the basic mechanisms of renal damage induced by alterations of their profile or metabolism. This preference of describing putative preventive FA ac- tions in the kidney to the assumed impact of their anoma- lous profile reverts the logical approach that would be based in the first place on biological plausibility and secondarily on intervention effects. A substantial proportion of publications describes indeed a variation of FA profile in different forms of nephrotic syn- drome, and furthermore experimental data underline the role of FA in the progression of renal damage in nephrotic patients. 3 Significant modifications in the FA profile of circulating lipids have been reported, in comparison to controls, in patients affected by chronic kidney disease (CKD), the most investigated renal condition as regards di- etary and pharmacologic treatment aimed at increasing the n-3PUFA (polyunsaturated FA) intake. Aim of the present review was to summarize the most relevant literature regarding changes in the profiles of FA and their metabolites in nephrotic syndrome and CKD, with the intent of elucidating their contribution in the development and progression of renal damage. General Overview on FAs FA profile in circulating lipids is an index of dietary intake, endogenous metabolism, and pathophysiological conditions, as suggested by the most recent scientific liter- ature. Several studies have confirmed the relationship be- tween health status and levels of selected FA and FA classes in various metabolic processes. 4 In particular, hard data are available on the association (either positive or nega- tive) between PUFA metabolism and both developmental issues 5 and cardiovascular disease risk factors. 6,7 The n-3 PUFA series has mainly positive effects on heart and brain-related functions, 8-11 while heterogeneous data are reported for the kidney, either considering CKD, 12 uri- nary tract inflammatory diseases, 13 or transplanted kidney. 1 Because a positive role for dietary n-3 PUFA on health is even recognized by official institutions, such as the Euro- pean Food Safety Authority, 14,15 a decrease in the level of omega-3, as reported in many diseases, needs monitoring and possibly supplementing. On the other size, n-6 show a dualistic role, both positive and negative, that depends mainly on the effects of their metabolites. 16 Even considering several confounding fac- tors, 17 a putative negative effect of n-6 in various diseases * Pediatric Department of Nephrology Dialysis and Transplantation, IRCCS C a Granda Ospedale Maggiore Policlinico, Milan, Italy. † Pediatric Clinic IRCCS C a Granda Ospedale Maggiore Policlinico, Milan, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy. ‡ Nutrition Foundation of Italy, Milan, Italy. Financial Disclosure: The authors declare that they have no relevant financial interests to disclose. Address correspondence to Stefano Turolo, BD, Pediatric Department of Nephrology Dialysis and Transplantation, IRCCS C a Granda Ospedale Mag- giore Policlinico, Via Della Commenda 9, Milan 20122, Italy. E-mail: stefano. turolo@gmail.com Ó 2017 by the National Kidney Foundation, Inc. All rights reserved. 1051-2276/$36.00 http://dx.doi.org/10.1053/j.jrn.2017.08.005 Journal of Renal Nutrition, Vol -, No - (-), 2017: pp 1-11 1