H LIEW1,2, MA ROBERTS1,2, L P MCMAHON1,2,
1Department of Renal Medicine, Box Hill, Melbourne, Victoria; 2Eastern Health Clinical School, Monash University, Melbourne, Victoria
Background: The endothelial glycocalyx (EG) on the endothelial luminal surface contributes to endothelial health and function. Its disruption is an early indicator of vascular damage. Increase of the perfused boundary region (PBR) in sublingual capillaries using the novel Glycocheck device is thought to reflect EG damage.
Aim: We aimed to examine the effects of uraemia on the EG by measuring the PBR, microalbuminuria and established biochemical markers of EG damage and endothelial dysfunction (ED).
Methods: A Glycocheck measurement was performed and blood and urine collected in healthy controls, patients with CKD (eGFR 15-60mL/min), and kidney transplant recipients. Urine (albumin:creatinine ratio, ACR) and serum (hyaluronan and von Willebrand factor, vWF) markers of ED) were measured using commercial ELISA kits.
Results: Mean ages were 40±13, 71±9, and 56±11 years (p<0.001) in the control (n=24), CKD (n=26) and transplant (n=27) groups respectively. Median (interquartile range) eGFR was 91 (70-91), 31 (10-59) and 59 (32-90) mL/min (p<0.001), and median ACR was 0.4 (0.0-2.0), 30.2 (0.0-637.0) and 5.3 (0.0-35.0) mg/mmol (p<0.001). The coefficient of variation for PBR measures was 9.6%. There was no difference in PBR between the groups: mean 2.09±0.30, 2.04±0.25, and 2.05±0.29µm (p=0.76). In contrast, serum markers of EG damage and ED were higher in CKD and transplant patients compared to controls. Median hyaluronan levels were 24.79 (7.99-115.77), 85.71 (28.4-257.14), and 56.69 (13.54-217.89) ng/L (p<0.001). Mean vWF levels were 1746.12±735.06, 3186.83±1008.10, and 2058.05±673.70 mIU/mL (p<0.001).
Conclusions: Although serum markers of EG damage and ED are higher in CKD and transplant patients compared to controls, no difference in PBR was detected.