IDENTIFICATION OF NOVEL BIOMARKERS OF KIDNEY FIBROSIS SUITABLE FOR HIGH-THROUGHPUT SCREENING OF ANTI-FIBROTIC AGENTS

Renal fibrosis is a key driver of chronic kidney disease (CKD) progression, yet its assessment still relies mainly on kidney biopsy, an invasive and specialized technique. This thesis aims to tackle this important issue, by investigating potential non-invasive biomarkers predictive of renal fibrosis, with innovative laboratory techniques and long-term follow-up of chronic patients. Further, this thesis aims to look into the effect of targeted therapies on renal fibrosis, with particular focus on patients with autoimmune conditions, such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS), where renal injury is mediated by immune dysregulation. First we analyzed the available evidence on serological biomarkers associated with renal fibrosis, evaluating the most promising biomarkers emerging in the last years. Despite some biomarkers being tested in different studies, evidence regarding their efficacy in assessing kidney fibrosis is still scattered and none of the biomarkers are routinely employed in clinical practice. Second, we focused our work in investigating promising biomarkers in renal involvement in patients with SLE and APS. In the context of lupus nephritis (LN), we evaluated Dickkopf homolog-3 (DKK3), observing higher levels in patients with prevalent CKD, higher chronicity index at the biopsy and rate of flares and that they also predicted the worsening of the renal function during the follow-up. To gain more insights into the ongoing pathological process in patients’ kidney, we explored the so-called “macryptins”, extracellular matrix fragments which are generated during fibrotic remodeling, observing that ECM-derived biomarkers (in particular Pro-C3 and Pro-C6) could provide a more accurate and dynamic monitoring of LN progression. In APS, we identified Caveolin-1 (Cav-1) as a potential immunohistochemical marker for APS nephropathy, with its expression linked to thrombotic microangiopathy, hence with a poorer prognosis. 5 Third, we investigated the histopathological significance of repeated biopsies during long-term follow-up in patients with SLE and we observed that early chronicity index scores are strong predictors of renal outcome in LN, suggesting that incorporating these assessment into clinical decision-making may improve risk stratification and inform therapeutic strategies aimed at preventing irreversible kidney damage. Fourth, we investigated new potential therapeutic approaches to manage refractory LN. In this particularly challenging subgroup of patients, Daratumumab showed promising efficacy and safety, and a role in modulating the underlying immunological, fibrotic and endothelial profile. In this thesis, we aimed to identify novel biomarkers of renal fibrosis suitable for high-throughput screening of anti-fibrotic agents. Notably, multiple measures capable of addressing the different aspects involved in this pathological condition (e.g. glomerular and tubular injury, and inflammation) could be the most suitable way to capture the high complexity characterizing renal fibrotic process, having consequently a great impact on clinical practice by maximizing prevention, diagnosis, and management. Overall, the identified biomarkers not only deepen our understanding of renal fibrotic mechanisms but also hold promise as candidate tools for high-throughput screening platforms aimed at discovering and evaluating novel anti-fibrotic therapies.