The Supportive Treatment of IgA Nephropathy and Idiopathic Nephrotic Syndrome: How Useful are Omega-3 Polyunsaturated Fatty Acids?

IgA nephropathy (IgAN) is the most prevalent glomerular disease in young adults worldwide, while idiopathic nephrotic syndrome (INS) represents the most frequent manifestation of glomerular disease in childhood. Over the years, studies have speculated about the potential benefits of omega-3 polyunsaturated fatty acids (PUFAs) in improving morbidity in both forms of chronic kidney disease (CKD). The proposed mechanisms of action include reduction of proteinuria and modulation of dyslipidemia. Although in vitro and in vivo experimental studies report the suppressive effect of omega-3 PUFAs on inflammatory pathways linked with the progression of nephropathy, the evidence supporting their beneficial effect in IgAN and INS is still weak. Also, their ability to regulate levels of total cholesterol, low-density lipoprotein-cholesterol (LDL-C), and triglycerides (TG) suggests that they could delay both dyslipidemia-associated nephrotoxicity and atherosclerosis. Most of the clinical trials that were conducted on their therapeutic benefits in IgAN patients reported positive outcomes with low and high doses of omega-3 PUFAs. However, few of the trials noted inconclusive findings, with low-quality evidence suggesting potential improvements in surrogate renal function outcomes. If the beneficial effect of omega-3 PUFAs is predicated on their hypolipidemic action, much higher doses could be used in well-designed randomized-controlled trials (RCTs) to determine if they could produce better renal function outcomes and provide much stronger evidence of their therapeutic benefits in IgAN and INS. However, the current hypothetical mechanisms of action in these forms of CKD also include the effect of omega-3 PUFAs on renal inflammatory pathways and glomerular proteinuria. Perhaps, the unresolved therapeutic efficacy of these fatty acids in IgAN and INS suggests that their exact mechanisms of action are yet to be fully established. In this narrative review, we aim to appraise the current evidence of their potential therapeutic benefits in these diseases.