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Background Peripheral arterial disease (PAD) is a major complication of haemodialysis (HD), especially in patients with diabetes mellitus. Although previous reports have indicated that low-density lipoprotein apheresis (LDL-A) improves arteriosclerosis in PAD patients, the mechanism by which LDL-A affects PAD is still unclear. In this study, we tested the hypothesis that LDL-A attenuates reactive oxygen species (ROS) production in HD patients with PAD. Methods Twenty HD patients with PAD were investigated in this study. Clinical effects were evaluated by thermography and angiography. Oxidative stress in serum was evaluated by thiobarbituric acid reactive substances (TBARS) and expression of p22phox mRNA. Results Ischaemic symptoms due to PAD were gradually improved in 13 patients (65%) after LDL-A. One session of LDL-A removed approximately 75% of LDL from serum. Some patients exhibited dramatic improvement of severe symptoms of PAD such as skin ulcers after serial performance of LDL-A. The levels of LDL cholesterol, malondialdehyde-modified LDL, high-sensitivity C-reactive protein, vascular endothelial growth factor, international normalized ratio of pro-thrombin time and bradykinin were decreased after a single session of LDL-A, although there were no additional changes after 10 sessions of LDL-A. The levels of fibrinogen and p22phox mRNA were decreased by a single session of LDL-A, and these decreases continued over the entire period of treatment. TBARS was decreased after a course of LDL-A. Conclusions LDL-A improved ischaemic symptoms in HD patients with PAD by reducing ROS production in leucocytes. We conclude that LDL-A is an effective therapy for patients with HD complicated by PAD.

Background Peritoneal mesothelial cells play an important role in peritoneal dialysis and are often exposed to dialysis fluid containing high glucose levels. Loss of peritoneal function is a major complication associated with long-term peritoneal dialysis. In this study, we hypothesized that high glucose levels induce apoptosis, and that insulin attenuates this apoptosis in peritoneal mesothelial cells. To clarify this hypothesis, we examined the effects of insulin on the phosphatidylinositol 3-kinase/Akt signaling pathway and apoptosis in rat peritoneal mesothelial cells. Methods Phosphorylated insulin receptor and Akt were detected by western blot analysis. Apoptosis was evaluated by measuring caspase 3 activity and by TUNNEL staining. Results Insulin (100 nmol/L) increased tyrosine phosphorylation of insulin receptor in peritoneal mesothelial cells. Furthermore, insulin (1-100 nmol/L) dose-dependently stimulated Akt phosphorylation. Treatment with the phosphatidylinositol 3-kinase inhibitors wortmannin (100 nmol/L) and LY294002 (10 micromol/L) attenuated insulin-induced Akt phosphorylation, indicating that insulin phosphorylates Akt via a phosphatidylinositol 3-kinase-dependent pathway. Insulin attenuated caspase 3 activity and decreased the number of TUNNEL-positive cells. The phosphatidylinositol 3-kinase inhibitors and overexpression of a dominant-negative mutant of Akt inhibited the effect of insulin on apoptosis. Conclusions The present data indicate that insulin attenuates high glucose-induced apoptosis via the phosphatidylinositol 3-kinase/Akt signaling pathway in peritoneal mesothelial cells. Therefore, the insulin signaling pathway may play a protective role in peritoneal function.