Fk Li

Differential expression of receptors for advanced glycation end-products in peritoneal mesothelial cells exposed to glucose degradation products

Autoclaving peritoneal dialysate fluid (PDF) degrades glucose into glucose degradation products (GDPs) that impair peritoneal mesothelial cell functions. While glycation processes leading to formation of advanced glycation end‐products (AGE) were viewed commonly as being mediated by glucose present in the PDF, recent evidence indicates that certain GDPs are even more powerful inducers of AGE formation than glucose per se. In the present study, we examined the expression and modulation of AGE receptors on human peritoneal mesothelial cells (HPMC) cultured with GDPs, conventional PDF or PDF with low GDP content. HPMC cultured with GDPs differentially modulated AGE receptors (including RAGE, AGE–R1, AGE–R2 and AGE–R3) expression in a dose‐dependent manner. At subtoxic concentrations, GDPs increased RAGE mRNA expression in HPMC. 2‐furaldehyde (FurA), methylglyoxal (M‐Glx) and 3,4‐dideoxy‐glucosone‐3‐Ene (3,4‐DGE) increased the expression of AGE–R1 and RAGE, the receptors that are associated with toxic effects. These three GDPs up‐regulated the AGE synthesis by cultured HPMC. In parallel, these GDPs also increased the expression of vascular endothelial growth factor (VEGF) in HPMC. PDF with lower GDP content exerted less cytotoxic effect than traditional heat‐sterilized PDF. Both PDF preparations up‐regulated the protein expression of RAGE and VEGF. However, the up‐regulation of VEGF in HPMC following 24‐h culture with conventional PDF was higher than values from HPMC cultured with PDF containing low GDP. We have demonstrated, for the first time, that in addition to RAGE, other AGE receptors including AGE–R1, AGE–R2 and AGE–R3 are expressed on HPMC. Different GDPs exert differential regulation on the expression of these receptors on HPMC. The interactions between GDPs and AGE receptors may bear biological relevance to the intraperitoneal homeostasis and membrane integrity.

Star fruit intoxication in uraemic patients: case series and review of the literature

Abstract

Clinicopathologic features of antineutrophil cytoplasm autoantibody (ANCA)-associated acute renal failure in Chinese patients

Summary: The clinical course and renal pathologic features of anti‐neutrophil cytoplasm auto‐antibody (ANCA)‐associated renal disease were studied among Chinese patients from a single centre. Eight ANCA positive patients with acute renal impairment were studied, four of whom required dialysis shortly after presentation. Their mean age at presentation was 61.6 ± 4.2 years. Renal histology, obtained in seven patients, showed paucummune crescentic glomerulonephritis in five patients, interstitial nephritis in two patients, and small vessel vasculitis in one patient. Pulmonary baemorrhage was the other common disease manifestation, present in four of the eight patients, necessitating ventilatory support in three patients. Neurologic, cutaneous, and gastrointestinal involvement were also observed. Seven of the eight patients tested positive for pANCA and anti‐myeloperoxidase, while cANCA was detected in one patient of the eight patients, six (75%) responded to therapy, consisting of prednisolone and cyclophosphamide in five patients, and antibacterial therapy alone in one patient, who had interstitial nephritis but no evidence of vasculitis. Two patients died from sepsis and severe debilitation one month after presentation. of the other six patients, five had significant improvement of renal function, while one became dialysis‐dependent. the levels of ANCA and C‐reactive protein remained normal, and disease reactivation was not observed during follow‐up for 32.4 ± 6.1 months. Patient and renal survival rates at one year were 75% and 62.5%, respectively. It was concluded that the clinical and pathologic features of ANCA‐associated renal disease in Chinese patients are, in general, similar to those described in Caucasians. Nevertheless, cANCA‐positivity is distinctly uncommon. the demonstration of interstitial nephritis in two of the eight patients underlines the importance of renal biopsy for correct histologic diagnosis. Early institution of aggressive immunosuppression and supportive therapies are essential for the achievement of favourable outcome in patients with vasculitis.