TGF-β: elusive target in diabetic kidney disease.

Transforming growth factor-beta (TGF-β), a cytokine with near omnipresence, is an integral part of many vital cellular processes across the human body. The family includes three isoforms: Transforming growth factor-beta 1, 2, and 3. These cytokines play a significant role in the fibrosis cascade. Diabetic kidney disease (DKD), a major complication of diabetes, is increasing in prevalence daily, and the classical diagnosis of diabetes is based on the presence of albuminuria. The occurrence of nonalbuminuric DKD has provided new insight into the pathogenesis of this disease. The emphasis on multifactorial pathways involved in developing DKD has highlighted some markers associated with tissue fibrosis. In diabetic nephropathy, TGF-β is significantly involved in its pathology. Its presence in serum and urine means that it could be a diagnostic tool while its regulation provides potential therapeutic targets. Completely blocking TGF-β signaling could reach untargeted regions and cause unanticipated effects. This paper reviews the basic details of TGF-β as a cytokine, its role in DKD, and updates on research carried out to validate its candidacy.