The Study Of Relationship Between Expression Level Of Receptor Activator Of NF-kappa B Ligand MRNA In Peripheral Blood Mononuclear Cell And Renal Osteodystrophy In Maintenance Hemodialysis Patients

Background: Receptor activator of NF -kappa B ligand (RANKL) is an important biological active substance which belongs to type Ⅱ transmembrane protein found in tumor necrosis factor receptor ligand superfamily in recent years. Its physiological function is to promote osteoclast formation, fusion, differentiation, activation, and survival, leading to enhanced bone resorption and bone loss. RANKL plays an important role in bone metabolism. Renal osteodystrophy is almost found in all end-stage chronic renal failure (ESCRF) patients. The accurate interactivity mechanism between RANKL and ESCRF has not yet clarified. Neither domestic nor overseas clinical report about relationship between transcriptional level of RANKL gene and renal osteodystrophy can be found.Objective: To investigate the change of expression level of RANKL mRNA in peripheral blood mononuclear cells ()in patients of ESCRF and the effects of hemodialysis on its mRNA expression. We also explored the significance that expression level of RANKL_mRNA in PBMCs and evaluated the true bone status in maintenance hemodialysis patients.Methods: Twenty-nine maintenance hemodialysis patients and twenty-three healthy people were recruited in this study. The level of expression of RANKL mRNA in PBMCs was assessed by half-quantitive RT-PCR. The intact parathyroid hormone was measured by radioimmunityassay. Alkaline phosphates, calcium, phosphate, BUN, and creatinine were also measured. The bone mineral density of lumbar spine, neck of femur, Ward's triangle of femur and trochanter of femur was measured by dual energy X-ray absorptionmetry. Data were analyzed by independent sample t-test, nonparametric test, correlation analysis, regression analysis.Results: The expression level of RANKL mRNA in single pre-dialysis and post-dialysis in study group were higher than control group (Z=-5.36, P<0.01 and Z—5.65, P<0.01 respectively). There was no significant change of expression level of RANKL mRNA between single pre-dialysis and post-dialysis (Z=-2.37,P=0.71). However, it distinctly enhanced that the post- dialytic expression level of RANKL mRNA of the patients whose serum IPTH concentration increased after HD compareing with the predialytic. And there was a correlation between the osseous status of nect of femur, ward's triangle and the expression level of RANKL mRNA in PBMCs. .A negative correlation between expression level of RANKL mRNA and age in health control was found (r = — 0.42 p<0.05). A negative correlation between expression level of RANKL mRNA and OPG serum concentration in health control was found (r=0.47 P=0.04. The bone mineral density analyzed by MANOVA in study group was lower than control group, while the bone mineral density of neck of femar, Ward's triangle of femar and trochanter of femur in study group was lower than control group. (P<0.01). No difference of lumbar spine bone mineral density was found between study group and control group.Conclusion: The expression level of RANKL_mRNA in PBMCs of ESCRF patients was higher than healthy people. And it correlate positively with the osseous status of the neck of femur and Ward's triangle of femar. It suggested that RANKLjnRNA can be in response to the severity of renal...