Association of serum and urinary galectin-3 with renal fibrosis in patients with lupus nephritis: A cross-sectional controlled study

Objective Our objective was to explore the correlation between serum (sGal-3) and urinary galectin-3 (uGal-3) levels and renal fibrosis (RF) severity in lupus nephritis (LN) patients, besides assessing their diagnostic performance for identifying moderate/severe interstitial fibrosis and tubular atrophy (IFTA). Methods This cross-sectional controlled study recruited 150 participants: 50 LN patients, 50 diagnosed with systemic lupus erythematosus (SLE) without LN, and 50 healthy controls. Both sGal-3 and uGal-3 levels were measured using ELISA. Histopathological assessment included evaluation of IFTA severity. Patients with LN were stratified into mild IFTA (<26%) and moderate/severe IFTA (≥26%). Moreover, we performed correlation, ROC curve, and multivariable logistic regression analyses. Results LN patients showed significantly higher sGal-3 and uGal-3 levels than other groups ( p < 0.001). Both biomarkers exhibited strong positive correlations with IFTA percentage (sGal-3: rho = 0.76; uGal-3: rho = 0.81; p < 0.001). Unlike those with mild IFTA, moderate/severe IFTA patients had significantly higher sGal-3 and uGal-3 levels ( p < 0.001). Based on ROC analysis, uGal-3 had higher discriminatory ability for moderate/severe IFTA (AUC = 0.903) than sGal-3 (AUC = 0.801). In multivariable logistic regression, both sGal-3 and uGal-3 levels were independently associated with moderate/severe IFTA after adjusting for renal function parameters. Conclusions Both sGal-3 and uGal-3 levels are significantly associated with RF severity in LN. The uGal-3 had superior diagnostic performance for moderate/severe IFTA and may be a promising non-invasive RF biomarker in LN. Validation in large-scale prospective studies is warranted.