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Background: Long-term peritoneal dialysis (PD) causes morphologic and functional changes in the peritoneum that hamper the continuation of PD therapy. Because macrophages play important roles in the development of peritoneal fibrosis and liposome-encapsulated clodronate (LC) induces macrophage apoptosis, we examined the effect of LC on chlorhexidine gluconate (CG)-induced peritoneal fibrosis in rats., Methods: Fifty Sprague-Dawley rats were randomly allocated into five groups of 10 receiving intraperitoneal (i.p.) injections (1.5 mL/100 g) of either 0.1% CG (four groups) or vehicle (one group) three times a week. Three of the CG-treated groups also received intravenous injections of clodronate twice a week: 10 mg of LC, 20 mg of LC or 20 mg of unencapsulated clodronate (UC20). Twenty-one days after the first i.p. injection, the rats were sacrificed and the parietal peritoneum was harvested., Results: The number of peritoneal macrophages in the rats given clodronate was significantly smaller than that in rats not given clodronate (92.0 ± 4.6 cells per field). It was 54.1 ± 3.2 cells per field in the group given 20 mg UC, 43.2 ± 5.2 cells per field in the group given 10 mg LC and 27.2 ± 2.8 cells per field in the group given 20 mg LC. This decrease in macrophage number was paralleled by decreases in peritoneal thickening, in the number of mesothelial cells staining positive for cytokeratin and α-smooth muscle actin and in messenger RNA expression for transforming growth factor-β1 and collagen types I and III., Conclusions: These data suggest that macrophages play a critical role in the development of peritoneal fibrosis and that LC may be useful for treating peritoneal fibrosis in PD patients.

Background: Corticosteroids are often used for the treatment of glomerular diseases. We examined whether bisphosphonate or vitamin D3 has beneficial effects on bone mineral density (BMD) in patients with glomerular diseases being treated with high-dose corticosteroids, including pulse therapy., Methods: Thirty-eight patients (19 men and 19 women, aged 42 +/- 16 years) were randomized into three groups: bisphosphonate alone (risedronate 2.5 mg/day, group R, n = 12), vitamin D3 alone (alfacalcidol 0.5 mug/day, group A, n = 15) and the combination of both agents (group R+A, n = 11). BMD at the lumbar spine was measured before and 12 months after treatment. The biochemical parameters of bone metabolism were assessed before and 3, 6 and 12 months after treatment., Results: In group R+A, BMD was significantly increased (+2.0%), whereas BMD was significantly decreased in group A (-5.6%). The BMD in group R did not show a significant change. In patients treated with steroid-pulse, BMD was decreased in groups R and A. In group R+A, BMD was significantly increased (+2.1%). Serum osteocalcin and alkaline phosphatase levels, markers of bone formation, were significantly decreased in all groups. Urinary crosslinked N-telopeptide of type I collagen (NTx) levels, a marker of bone resorption, were decreased in groups R and R+A. In patients with decreased BMD, the urinary NTx levels at baseline were significantly higher than the patients with increased BMD., Conclusions: Bisphosphonate might be beneficial for the prevention of steroid-induced bone loss in patients with glomerular diseases compared with vitamin D3. The combined therapy may be more effective, especially in patients treated with high-dose corticosteroids, including pulse therapy. A high urinary NTx level before receiving corticosteroids might be a predictive marker of the loss of BMD.

Background: We previously reported that fractalkine was upregulated in streptozotocin-induced diabetic kidneys. Fractalkine in diabetic kidneys was detected on glomerular capillaries and the mesangium. This upregulation was suppressed by treatment with angiotensin-converting enzyme inhibitor (ACE-I) or aminoiguanidine. We examined what factors induce fractalkine upregulation in normal rat glomeruli., Methods: Glomeruli were collected from the kidneys of normal Sprague-Dawley rats by a microdissection method. Ten glomeruli were incubated in a solution with glucose, mannitol, angiotensin II, tumour necrosis factor (TNF)-alpha and advanced glycation end-product (AGE)-bovine serum albumin (BSA) for 1, 2 and 4 h. Fractalkine mRNA expression in glomeruli was examined by reverse transcription-polymerase chain reaction., Results: Fractalkine mRNA levels in the 30 mM glucose solution significantly increased (121%) compared with those in the control or 30 mM mannitol solution at 1 h. Fractalkine mRNA levels in the 15 mM glucose solution showed no significant differences at 1 or 2 h, but significantly increased (106%) after 4 h incubation. Fractalkine mRNA levels in 10(-6)-10(-8) M angiotensin II solution showed no significant differences. Fractalkine mRNA levels in the 5 or 10 ng/ml TNF-alpha solution significantly increased compared with those in the control in a time- and dose-dependent manner (by 94 to 253%). Fractalkine mRNA levels in the 50-200 microg/ml AGE-BSA solution also increased compared with those in BSA solution in a time- and dose-dependent manner (by 119 to 261%). By pre-incubation with MG132, a nuclear factor-kappaB inhibitor, fractalkine upregulation by AGE-BSA or 30 mM glucose was completely suppressed., Conclusions: High glucose levels, AGE formation and cytokine activation in diabetes may induce fractalkine upregulation in the kidneys and lead to progression of diabetic nephropathy.