Neutrophil Gelatinase–Associated Lipocalin Drives Cardiac Remodeling in Rats With Chronic Kidney Disease

BACKGROUND: Patients with chronic kidney disease (CKD) are at high risk of cardiovascular complications. We have shown that Ngal (neutrophil gelatinase–associated lipocalin)/lcn2 is involved in aldosterone-induced cardiac remodeling and inflammation. Here, we investigated the role of Ngal in the progression of cardiorenal syndrome. METHODS: CKD was induced in rats via 5/6 nephrectomy in wild-type and Ngal knockout rats. Cardiorenal functions were assessed 3 months after subtotal nephrectomy or sham operation. Cardiac fibroblasts were isolated from wild-type rats and incubated with or without rNgal (recombinant Ngal) and Gal-3 (galectin-3). RESULTS: Cardiac perfusion was less impaired in CKD Ngal knockout than in CKD wild type. Left ventricle interstitial fibrosis was more severe in CKD wild type than in sham but was blunted in CKD Ngal knockout rats. Levels of Gal-3, Col1 (collagen 1), Ccl2 (C-C motif chemokine ligand 2), and IL-6 (interleukin-6) were high in cardiac fibroblasts incubated with rNgal. A similar pattern was observed in cells treated with recombinant Gal-3. Both Ngal and Gal-3 induced activation of the Tlr4 (toll-like receptor 4)-Myd88 (myeloid differentiation primary response 88) pathway. The effects of rNgal were blunted by concomitant treatment with Gal-3 or Tlr4 inhibitors, suggesting that Gal-3 contributes to Ngal-induced cardiac fibrosis and inflammation by activating the Tlr4-Myd88 pathway. In both MEDIA-DHF (Metabolic Road to Diastolic Heart Failure) and BIOSTAT-CHF (Biology Study to Tailored Treatment in Chronic Heart Failure) cohorts, elevated levels of Ngal and Gal-3 were associated with advanced diastolic dysfunction and adverse clinical outcomes, particularly among patients with impaired renal function. CONCLUSIONS: In CKD rats, Ngal was involved in cardiac remodeling via a Gal-3/Tlr4-dependent pathway, increasing inflammation and fibrosis, and correlated to cardiac outcomes in the MEDIA-DHF and BIOSTAT-CHF cohorts.