| PREFACELeptin , a recently discovered peptide, is the protein product of the ob gene. Leptin are related closely with the feeding behavior and the regulation of energy metabolism. In patients with chronic renal failure, the levels of leptin are obviously higher than those in the control group. As a uremic toxin causing anorexia, these studies on leptin and its determinants in patients with chronic renal failure have become hot spot. There are many studies about it, but the results are quite different. This study was undertaken to learn serum leptin levels and the determinants of serum leptin in patients with chronic renal failure , as well as to clarify the relationship between serum leptin and parathyroid hormone ( PTH) , a medium molecular toxin, which can result in anorexia and malnutrition.SUBJECTS AND METHODSSubjectsWe collected 55 patients with chronic renal failure caused by various reasons of diseases(29 men and 26 women) aged 48. 56 ± 14.41 years old( mean ± SD) and with a body mass index( BMI) of 22. 25 ± 3.02kg/m . At the same time,we collected 30 healthy subjects(16men and 14 women) matched for age,sex and BMI served as controls.MeasurementsBlood samples were taken after an overnight fast at 7 Am to measure serum creatinine (Scr) , albumin ( ALB ) , total cholesterol (TC ) , triglyceride ( TG ) , calcium ( Ca ) , phosphor ( P ) , alkaline phosphatase ( ALP) , serum leptin and serum PTH in patients with chronic renal failure. In healthy subjects we only measured the serum leptin by the same way. At the same time,the height and weight were measured for each subjects. Serum leptin levels were measured with a radioimmuno-assay kit and serum PTH levels were measured with a chemilumi -nescent immune kit. BMI was calculated by weight ( kg) /height2 ( m2) . The clearance rate of creatinine was calculated by simply formula : [( 140 - age ) x weight ( kg) ]/[ 72 x Scr( mg/ dl) ] (men) and [ ( 140 - age) x weight( kg) ]/ [ 85 x Scr( mg/dl) ] ( women) raised by Cockcroft and Gault et al.Statistical analysisAll data were presented as the mean ± SD. t test was used to compare differences. Simple and multiple stepwise regression analysis were used to evaluate the correlation between variables. Statistical analysis were obtained by SPSS 10. 0 software package. A P value less than 0. 05 was considered significant.RESULTS1 Serum leptin levels in patients with chronic renal failure and in normal controlsSerum leptin levels in chronic renal failure patients were obviously higher than those in normal controls and they had statistical differences ( 18. 69 ±6.96ng/ml vs. 8.09 ±4. 54 ng/ml,p <0.001). Leptin concentrations in female subjects were higher than those in male subjects in both chronic renal failure and control group ( chronic renal failure group :23. 19 ± 6. 01 ng/ml vs. 14. 66 ± 5.06ng/ml, p< 0.001; control group : 11. 16 ±4. 6 9 ng/ml vs.5.41 ±2.07 ng/ml,p< 0.001).We defined BMI ^ 25kg/m2 as obesity. Both genders in two groups were divided into obese and non - obese group in which serum leptin levels were compared. It was found that serum leptin levels in non - obese group were significandy lower than those in obese group in both genders( control group:men4. 55 ± 1. 12ng/ml vs. 7. 97 ±2.21 ng/ml,p= 0.0011; women 9.51 ±3.54ng/ml vs. 17. 22 ±3. 27 ng/ ml, p =0.0054; chronic renal failure group:men 13.61 ±4.56ng/ml vs. 19.67 ±4.67 ng/ml,p= 0.012; women 21.97 ±5.69ng/ml vs. 29.89±1.99ng/ml, p =0.012).2 Determinants of serum leptin levels in chronic renal failure groupSimple correlation analysis showed that there was only significant correlation between serum leptin levels and BMI (r=0.478,p< 0. 001) , gender( r = 0. 618, P < 0.001) in chronic renal failure group , and in control group, we also found the significant correlation between serum leptin levels and BMI ( r = 0. 375 , p = 0. 041 ) , gender( r = 0.644,P<0.001).In a multiple linear stepwise regression analysis ,with serum leptin levels as dependent variable and other variables as inde...
|
PDF Full Text Request