The present study describes upregulation of gene transcription for several fibrosis mediators, including HIF1A, MMP2, MMP7, MMP9, TIMP1, and TGFB1, as well as downregulation of the proangiogenic factor VEGFA, in renal tissues from cats with naturally occurring CKD, when compared to those from healthy control cats. Here, TGFB1 is linked to chronic kidney disease.