Kidney Fibrosis: Origins and Interventions

Area of Science:

• Nephrology
• Transplantation Immunology
• Fibrosis Research

Background:

• Severe or sustained renal allograft injury commonly causes chronic histological damage, characterized by interstitial fibrosis and tubular atrophy.
• The precise drivers of fibrosis and atrophy progression in individual patients often remain unclear without identifying a specific underlying disease process.

Purpose of the Study:

• To review clinicopathological factors influencing renal allograft fibrosis progression.
• To evaluate the impact of current and novel therapeutic strategies on chronic histological damage in renal allografts.

Main Methods:

• Literature review of factors predicting and driving allograft fibrosis.
• Analysis of evidence for current immunosuppressive strategies (e.g., calcineurin inhibitor minimization, steroid minimization, renin-angiotensin-aldosterone system blockade) on histology.
• Exploration of emerging antifibrotic targets and their potential applications in renal transplantation.

Main Results:

• Clinicopathological factors such as graft quality, inflammation, infections (e.g., polyomavirus-associated nephropathy), calcineurin inhibitors (CNI), and genetic factors contribute to allograft fibrosis.
• While chronic damage has decreased, the specific impact of innovations like lower CNI dosing and BK viremia screening is hard to isolate.
• Current strategies like CNI-sparing, steroid minimization, and RAS blockade show limited evidence for improving intermediate-term histology. Treatment of subclinical rejection is beneficial only when rejection rates exceed 10-15%.

Conclusions:

• Novel antifibrotic strategies targeting pathways like TGF-β, CTGF, tyrosine kinase ligands, endothelin, and chemotaxis inhibitors hold potential for treating renal allograft fibrosis.
• These agents, some developed for oncology and idiopathic pulmonary fibrosis, may also benefit diabetic nephropathy and eventually find applications in renal transplantation.