Backgroundand Aims: Calcium-containing phosphate binders have been shown to increase the progression of vascular calcification in hemodialysis patients. This is a prospective study that compares the effects of calcium acetate and sevelamer on coronary calcification (CAC) and bone histology. Methods: 101 hemodialysis patients were randomized for each phosphate binder and submitted to multislice coronary tomographies and bone biopsies at entry and 12 months. Results: The 71 patients who concluded the study had similar baseline characteristics. On follow-up, the sevelamer group had higher levels of intact parathyroid hormone (498 ± 352 vs. 326 ± 236 pg/ml, p = 0.017), bone alkaline phosphatase (38 ± 24 vs. 28 ± 15 U/l, p = 0.03) and deoxypyridinoline (135 ± 107 vs. 89 ± 71 nmol/l, p = 0.03) and lower LDL cholesterol (74 ± 21 vs. 91 ± 28 mg/dl, p = 0.015). Phosphorus (5.8 ± 1.0 vs. 6 ± 1.0 mg/dl, p = 0.47) and calcium (1.27 ± 0.07 vs. 1.23 ± 0.08 mmol/l, p = 0.68) levels did not differ between groups. CAC progression (35 vs. 24%, p = 0.94) and bone histological diagnosis at baseline and 12 months were similar in both groups. Patients of the sevelamer group with a high turnover at baseline had an increase in bone resorption (eroded surface, ES/BS = 9.0 ± 5.9 vs. 13.1 ± 9.5%, p = 0.05), whereas patients of both groups with low turnover at baseline had an improvement in bone formation rate (BFR/BS = 0.015 ± 0.016 vs. 0.062 ± 0.078, p = 0.003 for calcium and 0.017 ± 0.016 vs. 0.071 ± 0.084 μm³/μm²/day, p = 0.010 for sevelamer). Conclusions: There was no difference in CAC progression or changes in bone remodeling between the calcium and the sevelamer groups.

Coronary calcification is highly prevalent in pre-dialysis patients and correlates with traditional and non-traditional risk factors for CVD.

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We evaluated neutrophil activation by measuring its phagocytic ability and oxidative burst activity in 16 patients with sepsis and 16 healthy volunteers. We also focused on neutrophil apoptosis as a regulatory mechanism of the inflammatory response. Neutrophil phagocytosis was evaluated by the detection of propidium iodide (PI)-labeled Staphylococcus aureus added to whole blood. Reactive oxygen species (ROS) formation was quantified by measuring the oxidation of 2',7' dichlorofluorescein diacetate (DCFH-DA) at baseline and after cell stimulation with phorbol myristate acetate (PMA), and bacterial cells (killed S. aureus) or products (lipopolysaccharide [LPS] and N-formyl-methionyl-leucyl-phenylalanine [FMLP]). Apoptosis was assessed in neutrophils stained with annexin V and PI. Neutrophil phagocytic ability was increased in patients with sepsis compared with healthy controls (median geometric mean fluorescence intensity [GMFI] was 101.9 and 54.7, respectively; P = 0.05). ROS formation was enhanced in patients with sepsis compared with healthy volunteers at baseline (median GMFI 275.6 and 52.1, respectively; P < 0.001), and after stimulation with S. aureus (median GMFI 2395.8 and 454.9, respectively; P < 0.001), PMA (median GMFI 1120.6 and 307.5, respectively; P = 0.003), FMLP (median GMFI 792.4 and 123.2, respectively; P < 0.001), and LPS (median GMFI 624.8 and 144.8, respectively; P < 0.001). Early neutrophil apoptosis was increased in patients with sepsis compared with healthy volunteers (median 11.3% and 9.1%, respectively; P = 0.03). These data demonstrate that neutrophil function is enhanced in patients with sepsis. Additionally, circulating neutrophils from patients with sepsis presented with increased early apoptosis, which may be consequence of a regulatory mechanism of the inflammatory response.

Our results suggest that both uraemia and treatment modality may interfere with PMN apoptosis and function. Dialysis appears to normalize the increased PMN apoptosis rates observed in CKD patients.