Serum levels of 12 renal function and injury markers in patients with glomerulonephritis

INTRODUCTION    Glomerulonephritis (GN) is a complex disease that affects the function of the whole nephron. There are few data on the serum levels of the most common biomarkers of kidney function and injury in GN, or the studies provide ambiguous results.
OBJECTIVES    The aim of the study was to evaluate the levels of known kidney-specific and nonspecific markers of renal function or injury in the serum of patients with diagnosed primary or secondary GN, with or without the presence of nephrotic syndrome (NS) and arterial hypertension (AH).
PATIENTS AND METHODS    The study included 58 patients with diagnosed GN and 6 patients with congenital defects (CD) of the kidney and AH (CD+AH). The serum levels of β2-microglobulin (β2M), neutrophil‑gelatinase associated lipocalin (NGAL), osteopontin, trefoil factor 3 (TFF-3), calbindin, glutathione-S‑transferase-π (GST-π), interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), and monocyte chemoattractant protein 1 (MCP-1) were measured with Kidney Toxicity Panels 1 and 2 using the Bio-Plex method. Renalase levels were measured using an enzyme-linked immunosorbent assay.
RESULTS    In the whole group and in the subgroups (GN, GN+AH, GN+NS, CD+AH), NGAL, KIM-1, TFF-3, IL-18, β2M, and calbindin levels correlated with estimated glomerular filtration rate (eGFR). In patients with NS, this correlation for calbindin was reversed. Renalase, MCP-1, GST-π, and osteopontin levels were independent of eGFR. Increase in IL-18 levels in the group with GN was assiociated with lower odds of the kidney disease. When this group was divided according to eGFR into subgroups G1–G5, TFF-3, NGAL, and β2M levels increased with the stage of the disease.
CONCLUSIONS In patients with NS, renalase and MCP-1 might regulate each other’s levels. Further studies are needed to investigate associations between renalase, MCP-1, and osteopontin as factors unrelated to eGFR in GN. NS may contribute to the loss of calbindin from serum. NGAL, KIM-1, TFF-3, IL-18, β2M, and calbindin are good indicators of kidney function loss in patients with GN.