Table 1.
Demographic, clinical, anthropometric, and biochemical characteristics of patients and control subjects.
Figure 1.
Circulating Ang levels in pre-dialysis CKD and dialysis patients.
Serum Ang-1 levels (A) were significantly lower in pre-dialysis CKD patients compared with healthy controls. In dialysis patients Ang-1 levels were similar to values found in healthy controls. Similar levels of both circulating Ang-2 (B) and Ang-2/Ang-1 (C) were found in healthy children and those with pre-dialysis CKD, but these were significantly increased in the dialysis group.
Figure 2.
Correlation of Ang-2 levels with clinical and vascular parameters.
Ang-2 levels in dialysis individuals correlated positively with time on dialysis (A), serum urate levels (B), systolic blood pressure SDS (C) and cIMT (D). Independent variables are shown on the x-axis. Regression lines account for dialysis patients only. Dotted line in D indicates the value for cIMT in healthy age-matched controls. There was no correlation between Ang-2 and any clinical and vascular measures in pre-dialysis CKD patients.
Table 2.
Multiple regression analyses for independent predictors of Angiopoietin-2 (Ang2) and carotid intima media thickness (cIMT).
Figure 3.
Circulating levels of VEGF-A and sFlt-1 in pre-dialysis CKD and dialysis patients.
VEGF-A levels were significantly lower in individuals on dialysis compared with pre-dialysis CKD patients (A). In contrast, sFlt-1 were significantly higher in the dialysis patients (B)
Figure 4.
Circulating levels of soluble cell adhesion molecules.
Compared with pre-dialysis CKD individuals, patients treated with dialysis had significantly elevated levels of soluble E-selectin (A), P-selectin (B) and VCAM-1 (C); there was no difference in ICAM-1 levels (D).
Figure 5.
Immunolocalisation of vascular growth factors in arteries.
Ang-1 was detected in the media of vessels from both pre-dialysis CKD (A) and dialysis patients (B); no differences in staining intensity were observed between the two groups (C). Ang-2 was immunodetected in both the media and endothelia (arrows) in pre-dialysis CKD (D) and dialysis (E) vessels with similar intensity (F). The endothelial later was also positive for von Willebrand factor (arrows, G and H). VEGF-A immunostaining was prominent in the media of pre-dialysis CKD vessels (I), but was significantly decreased in dialysis patients (J and K). All fields taken with ×40 objective.
Figure 6.
Effect of uric acid on Ang-2 secretion in HUVECs.
A) Both non-stimulated and uric acid stimulated HUVECs expressed the mRNA for the transporter Urat1 but not Oat1-4; they were also positive for Ang-1, Ang-2, Tie-1, Tie-2 and Tlr4. Sizes were determined using a 100 bp marker (m), positive (+ive) controls consisted of total kidney cDNA and negative controls were without cDNA addition. (B) Uric acid stimulation for 15 minutes, but not 72 hours (C) led to elevated Ang-2 secretion in the conditioned media of HUVEC cells. Within the cells, uric acid stimulation led to a decreased abundance of Ang-2 mRNA after 6 hours of stimulation (D). a = p<0.05 compared with controls, b = p<0.01 compared with controls, c = p<0.001 compared with controls, d = p<0.01 compared with HUVEC stimulated with 3 mg/dl uric acid, e = p<0.01 compared with HUVEC stimulated with 6 mg/dl uric acid, f = p<0.05 compared with HUVEC stimulated with 9 mg/dl uric acid.
Table 3.
Changes in circulating angiogenic and inflammatory markers between pre-dialysis CKD and dialysis patients.