Sevelamer carbonate lowers serum phosphorus effectively in haemodialysis patients: a randomized, double-blind, placebo-controlled, dose-titration study

BACKGROUND

Hyperphosphataemia in patients with advanced chronic kidney disease (CKD) is associated with adverse outcomes, including vascular calcification and higher mortality rates. While phosphate lowering is an integral aspect of CKD management, the efficacy and safety of phosphate binders in a contemporary cohort of Chinese haemodialysis patients (who have different genetics and dietary patterns than other populations) has not been previously described. Moreover, sparse data are available on strategies for optimal dose titration when transitioning from a calcium-based to a polymer-based phosphate binder.

METHODS

This randomized, double-blind, dose-titration study compared sevelamer carbonate (starting dose 800 mg three times daily) with placebo over 8 weeks' duration in Chinese CKD patients on haemodialysis. Patients were required to be using calcium-based binders prior to study start.

RESULTS

In all, 205 patients were randomized (sevelamer, n = 135; placebo, n = 70); mean age was 48.6 years, 61% were male and the mean time on dialysis was 4.4 years. The mean serum phosphorus decreased significantly in patients treated with sevelamer carbonate [change -0.69 ± 0.64 mmol/L (-2.14 ± 1.98 mg/dL)] but remained persistently elevated with placebo [change -0.06 ± 0.57 mmol/L (-0.19 ± 1.76 mg/dL)] (P < 0.0001). When compared with placebo, sevelamer carbonate treatment resulted in statistically significant greater mean reductions from baseline in serum total (-17.1 versus -3.3%) and low-density lipoprotein cholesterol (-33.5 versus-7.6%) (P < 0.0001 for both). Sevelamer carbonate was well tolerated with 96% adherence compared with 97% adherence in the placebo arm. Overall, adverse events experienced by patients in the sevelamer carbonate and placebo treatment groups were similar and consistent with their underlying renal disease.

CONCLUSIONS

This study demonstrated that hyperphosphataemia developed quickly following the cessation of phosphate binders and remained persistently elevated in end-stage CKD in the placebo-treated group. Gradually titrating up sevelamer carbonate from an initial dose of 2.4 g/day to an average daily dose of 7.1 ± 2.5 g/day was well tolerated, safe and efficacious in contemporary Chinese haemodialysis patients.

Abnormal changes of plasma acute phase proteins in schizophrenia and the relation between schizophrenia and haptoglobin (Hp) gene

In this study we focused on detecting schizophrenia related changes of plasma proteins using proteomic technology and examining the relation between schizophrenia and haptoglobin (Hp) genotype. We investigated plasma proteins from schizophrenic subjects (n = 42) and healthy controls (n = 46) by two-dimensional gel electrophoresis (2-DE) in combination with mass spectrometry. To further reveal the genetic relationship between acute phase proteins (APPs) and schizophrenia disease, we tested Hp alpha1/Hp alpha2 (Hp 1/2) polymorphism and two single nucleotide polymorphisms (SNPs) of Hp, rs2070937 and rs5473, for associations with schizophrenia in the Chinese Han population. With the relatively high number of samples for 2-DE work, we found that four proteins in the family of positive APPs were all up-regulated in patients. In genetic association study, we found significant associations existing between schizophrenia and Hp polymorphisms, Hp 1/2 and rs2070937 variants. Schizophrenia is accompanied by both an altered expression of Hp protein and a different genotype distribution of Hp gene, demonstrating that Hp is associated with schizophrenia. The results from proteomic and genomic aspects both indicate that acute phase reaction is likely to be an aetiological agent in the pathophysiology of schizophrenia, but not just an accompanying symptom. The positive APPs are schizophrenic related proteins, with the highly concordant results on four positive APPs.

[Effect of exercise on glucose transporter gene expression in diabetic rat skeletal muscle]

OBJECTIVE

To investigate the effect of the exercise on glucose transporter 4 (GLUT4) gene expression in skeletal muscles of rats with streptozotocin-induced diabetes.

METHODS

Three experiment groups of rats were investigated: diabetic non-exercise group; diabetic exercise group; and normal controls. Diabetic exercise rats were swim-trained for 6 weeks. The GULT4 mRNA of skeletal muscle cells was determined with dot blot.

RESULTS

There was weak gene expression of GULT4 in diabetic rats, and dot blot revealed that the GLUT4 mRNA decrease 54.9% in skeletal muscle cells compared with the normal control. After 6 weeks exercise training, the hyperglycemia of diabetic exercise rats decreased significantly (from 18.5 +/- 1.9 mmol/L to 14.0 +/- 3.3 mmol/L, t = 4.64 P < 0.01). In muscle cells of diabetic exercise rats, the GLUT4 mRNA increased 56% as compared with the diabetic rats (t = 15.56, P < 0.01).

CONCLUSION

Chronic hyperglycemia may inhibit the gene expression of GLUT4 in diabetic rats, which caused the post-receptor insulin resistance in peripheral tissue. Exercise training can improve the impaired GLUT4 expression in diabetic rats, which may contribute to the mechanisms of enhanced insulin sensitivity and decreased hyperglycemia in diabetics mellitus.