Mechanisms of tubulointerstitial fibrosis

Masayuki Iwano, Eric G. Neilson*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

207 Scopus citations


Purpose of review: Tubulointerstitial fibrosis is the final common pathway to endstage renal disease. Understanding the mechanisms of tubulointerstitial fibrosis is essential in establishing novel therapeutic strategies for the prevention or arrest of progressive kidney diseases. The present review focuses on a newly proposed mechanism of tubulointerstitial fibrosis, one that emphasizes the roles of epithelial-mesenchymal transition and cellular activation. Recent findings: Among the cells that accumulate in the renal interstitium, fibroblasts are the principal effectors mediating tubulointerstitial fibrosis. By contrast, the phagocytosis of extracellular matrix and apoptotic cells by macrophages may actually exert a beneficial effect. Interstitial fibroblasts are more heterogeneous than expected, and during renal fibrosis new fibroblasts are derived mainly through epithelial-mesenchymal transition. The intracellular signaling pathways leading to initiation of epithelial-mesenchymal transition remain largely unknown, though recent studies have identified β-catenin and Smad3 activation of lymphoid enhancer factor, integrin-linked kinase, and small GTPases and mitogen-activated protein kinases as key components. Transforming growth factor-β is believed to be a critical fibrogenic factor, but recent studies have also focused on transforming growth factor-β independent pathways as mechanisms of tubulointerstitial fibrosis. As the mechanisms underlying tubulointerstitial fibrosis leading to epithelial-mesenchymal transition have been identified, so have cytokines that efficiently antagonize renal fibrosis, particularly bone morphogenic protein-7 and hepatocyte growth factor. Summary: In combination with traditional angiotensin converting enzyme inhibitors, newly identified cytokines may eventually form the basis for new therapeutic strategies aimed at inhibiting the progression of renal disease.

Original languageEnglish (US)
Pages (from-to)279-284
Number of pages6
JournalCurrent opinion in nephrology and hypertension
Issue number3
StatePublished - May 2004


  • Epithelial-mesenchymal transition
  • FSP1
  • Fibrosis
  • Renal disease
  • Renal progression

ASJC Scopus subject areas

  • Internal Medicine
  • Nephrology


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