B2M and heart failure: In addition to known markers of renal dysfunction that accumulate when glomerular filtration is impaired (George and Gounden, 2019), such as PTGDS, LTBP2, F13A1, and the secreted factors cystatin C (CST3, Figure 3D) and beta-2 microglobulin (B2M) (Figure 3E), we also detected leucine-rich alpha-2-glycoprotein (LRG1) (Figure 3F), previously suggested (Glorieux et al., 2015) as an indicator of vascular damage and heart failure; TXNDC5, a mediator of cardiac fibrosis (Chen et al., 2021); and calreticulin (CALR, Figure 3C), a marker of renal fibrosis (Lu et al., 2020).