On this regard, we believe that our animal and in vitro experimental design might offer a good platform to investigate its contribution to renal fibrosis onset in all those conditions that, beside renal failure, may lead to increased level of circulating IS, such as gut microbiota disequilibrium, reduced plasma albumin, and unbalanced IS/albumin ratio for binding competition with other uremic compounds [31]. This evidence concerns the gene ALB and acute kidney injury.