APLN and metabolic syndrome: This review highlights the potential role of several biomarkers—angiopoietin-like protein 4 (ANGPTL4), angiopoietin-like protein 8 (ANGPTL8), lipocalin-2 (LCN2/NGAL), CTRP-3, CTRP-9, apelin, and galectin-3 (Gal-3)—in the early detection of microvascular complications in individuals with MetS.