Ai-Hua Zhang

Changes of urinary phospholipids in the chronic kidney disease patients

Abstract Objective: To evaluate whether urinary phospholipids could be regarded as biomarkers of chronic kidney disease. Materials and methods: Thirteen healthy volunteers and 26 consecutive chronic kidney disease patients were included. Urinary phospholipids were quantified by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Results: Urinary phosphatidylcholines concentrations (PC 16:0/16:0, 16:0/22:3, 16:0/18:1 and 16:0/18:2) were significantly higher both in glomerulonephritis group (all p < 0.001) and in tubulointerstitial injury group (all p < 0.05) than in healthy control group. Meanwhile, sphingomyelin concentrations (SM 18:1/16:0 and 18:1/18:0) in glomerulonephritis group were significantly higher than those in healthy control group (all p < 0.001). Urinary PCs and SMs were positively correlated with proteinuria but negatively correlated with serum albumin. Meanwhile, PCs were positively correlated with serum creatinine. Conclusion: Our work first demonstrated that urinary phospholipids might be biomarkers for the chronic kidney disease patients. Increased urinary phospholipids in chronic kidney disease patients might result from proteinuria, damaged kidney function or proteinuria induced hypoalbuminemia or lipotoxicity.

Metabolic syndrome and its components associated with endothelial dysfunction in chronic kidney disease patients

Background Cardiovascular disease is more common in patients with chronic kidney disease (CKD) than in the general population. Endothelial dysfunction is an early predictor of cardiovascular events. Objective We conducted a cross-sectional study in CKD patients to explore the association of metabolic syndrome (MetS) components with endothelial cell function. Methods We evaluated clinical and laboratory data in 161 CKD patients from stage 1 to stage 5. Endothelial function was estimated by flow-mediated dilatation (FMD) of the brachial artery and expressed as percentage change relative to baseline diameter. MetS was defined according to the National Cholesterol Education Program-Adult Treatment Panel III criteria. Results Patients were grouped into two groups according to whether or not they had MetS. FMD was significantly lower in the MetS group than in the group without MetS (P = 0.012). In a Pearson’s correlation analysis, FMD was significantly negatively correlated with waist circumference in women (r = −0.223, P = 0.03) and fasting blood glucose (r = −0.186, P = 0.001). Multiple linear regression analysis showed that fasting blood glucose was an independently associated factor for FMD. Conclusion MetS and some components of MetS (waist circumference in women and fasting blood glucose) are closely associated with a decreased FMD in CKD patients.

Metabolic syndrome is associated with better nutritional status, but not with cardiovascular disease or all-cause mortality in patients on haemodialysis

BACKGROUND Metabolic syndrome increases the risk of cardiovascular disease (CVD) and all-cause mortality in the general population. AIMS To investigate whether metabolic syndrome affects CVD and all-cause mortality in chronic haemodialysis patients. METHODS This prospective, observational cohort study was carried out at Peking university third hospital from June 2006 to June 2010. Baseline anthropometric and laboratory parameters were evaluated, and causes and times of mortality were documented. Nutritional status of the patients was assessed using subject global assessment (SGA) and serum albumin levels. RESULTS Of 162 haemodialysis patients recruited, five were lost to follow-up, leaving 157 in the final cohort, who were followed for 36-42 months. Mean age was 62 ± 11 years and 55.4% were men. Forty-six patients (30%) had metabolic syndrome. In the metabolic syndrome versus the non-metabolic syndrome group, there were fewer patients with malnutrition (by SGA) (15.2% vs. 55.0%; P < 0.001), but there were no significant differences in CVD mortality (8.7% vs. 10.8%; P = 0.9) or all-cause mortality (15.2% vs. 22.5%; P = 0.39), nor in mean observed survival time (30.8 ± 7.3 vs. 29.8 ± 8.5 months; P = 0.49) or total survival time (67 ± 43 vs. 78 ± 48 months; P = 0.20). Cox regression analysis showed that independent mortality risk factors were pre-existing CVD, age more than or equal to 66 years and serum albumin less than 37 g/L (indicating malnutrition). CONCLUSION Metabolic syndrome was associated with a better nutritional status, but not with CVD or all-cause mortality in the haemodialysis patients in this prospective cohort study.

Outcomes of stage 1-5 chronic kidney disease in Mainland China.

Abstract Objective: This study aims to quantify and compare the risks of death and end stage renal disease (ESRD) in a prospective cohort of patients with chronic kidney disease (CKD) stages 1–5 under renal management clinic at Peking University Third Hospital and to evaluate the risk factors associated with these two outcomes. Method: This was a prospective cohort study. Finally, 1076 patients at CKD stage 1–5 short of dialysis were recruited from renal management clinic. Patients were monitored for up to Dec, 2011 or until ESRD and death. Glomerular filtration rate was estimated (eGFR) according to the using the CKD Epidemiology Collaboration (CKD-EPI) formula. Results: At the end of follow-up, 111 patients (10.1%) developed ESRD (initiated dialysis or kidney transplantation (ESRD)) and 24 patients (2.2%) had died. There were more ESRD occurrence rate in patients with baseline diabetic nephropathy, lower eGFR, hemoglobin <100 g/L and 24 h urinary protein excretion ≥3.0 g. By multivariate Cox regression model, having heavy proteinuria and CKD stage were the risk factors of ESRD. For all-cause mortality, the most common cause was cardiovascular disease, followed by infectious disease and cancer. But we failed to conclude any significant variable as risk factors for mortality in multivariate analysis. Conclusions: Our study indicated that baseline diabetic nephropathy, lower hemoglobin level, lower baseline GFR and heavy proteinuria were the risk factors of ESRD. In this CKD cohort, patients were more likely to develop ESRD than mortality, and cardiovascular mortality was the leading cause of death, and then followed by infectious diseases and cancer in this population.

The Effect of Decreased Residual Renal Function on Endothelial Function in CAPD Patients

1. Koyner JL, Bennett MR, Worcester EM, Ma Q, Raman J, Jeevanandam V, et al. Urinary cystatin C as an early biomarker of acute kidney injury following adult cardiothoracic surgery. Kidney Int 2008; 74:1059–69. 2. Hellerstein S, Berenbom M, Erwin P, Wilson N, DiMaggio S. The ratio of urinary cystatin C to urinary creatinine for detecting decreased GFR. Pediatr Nephrol 2004; 19: 521–5. 3. Uchida K, Gotoh A. Measurement of cystatin C and creatinine in urine. Clin Chim Acta 2002; 323:121–8. 4. Kyhse-Anderson J, Schmidt C, Nordin G, Andersson B, Nilsson-Ehle P, Lindström V, et al. Serum cystatin C, determined by a rapid, automated particle-enhanced turbidimetric method, is a better marker than serum creatinine for glomerular f iltration rate. Clin Chem 1994; 40: 1921–6. 5. Filler G, Bökenkamp A, Hofmann W, Le Bricon T, MartínezBrú C, Grubb A. Cystatin C as a marker of GFR—history, indications, and future research. Clin Biochem 2005; 38:1–8. 6. Montini G, Amici G, Milan S, Mussap M, Naturale M, Rätsch IM, et al. Middle molecule and small protein removal in children on peritoneal dialysis. Kidney Int 2002; 61: 1153–9. 7. King AJ, Levey AS. Dietary proteins and renal function. J Am Soc Nephrol 1993; 3:1723–37. doi:10.3747/pdi.2009.00045 The Effect of Decreased Residual Renal Function on Endothelial Function in CAPD Patients

Roles of human urotensin II in volume resistance hypertension in peritoneal dialysis patients.

Human urotensin II (hUII) is a newly discovered substance that can dilate small blood vessels to decrease the blood pressure (BP). Our previous studies showed that some volume-overloaded patients on peritoneal dialysis can maintain normal BP (congestive heart failure excluded), suggesting that these patients have volume resistance capacity. This study is to investigate whether hUII plays an important role in this subgroup of patients on peritoneal dialysis. In this study, 105 patients on continuous ambulatory peritoneal dialysis were enrolled. Volume load was evaluated by the overhydration (OH) value obtained by bioimpedance analysis. OH < 2.0 kg was defined as normal volume (NV), and OH ≥ 2.0 kg as high volume (HV). Systolic blood pressure (SBP) <130 mmHg was defined as normotension (NT) and ≥130 mmHg as hypertension (HT). The patients were thus divided into four subgroups: (1) normotension with normal volume (NT-NV), (2) normotension with high volume (NT-HV), (3) normal volume with hypertension (HT-NV), and (4) high volume with hypertension (HT-HV). hUII was measured using radioimmunoassay method. hUII was significantly higher in normal SBP group than that in high SBP group (p < 0.05). hUII was higher in the NT-HV group compared with that in the HT-HV group (p < 0.05). Our study suggests that hUII may be involved in the pathogenesis of the volume resistance HT in peritoneal dialysis patients.

Lower Serum Irisin Levels Are Associated with Increased Vascular Calcification in Hemodialysis Patients.

Background/Aims: Vascular calcification, which involves an active cellular transformation of vascular smooth muscle cells into bone forming cells, is prevalent and predicts mortality in dialysis patients. Its mechanisms are complex and unclear. We presume that irisin, a newly identified myokine also may play roles in vascular calcification in hemodialysis patients. This study aims to evaluate serum irisin levels and establish their relation to vascular calcification and other parameters in hemodialysis patients. Methods: A total of 150 patients on maintenance hemodialysis treatment and 38 age- and sex-matched healthy controls were enrolled in this cross-sectional study. Serum irisin concentrations were measured by ELISA. Vascular calcification was evaluated by abdominal aortic calcification scores. Results: Serum irisin concentrations were significantly lower in hemodialysis patients than in controls [52.8 (22.0, 100.0) vs. 460.8 (434.8, 483.4) ng/ml, P<0.01]. In addition, irisin was negatively correlated with the parathyroid hormone level (P=0.01). The HD patients with vascular calcification showed significantly lower serum irisin concentrations [39.0 (21.7, 86.2) vs.79.0 (39.5, 130.2) ng/mL, P<0.01]. Compared with the group without vascular calcification multivariate logistic regression analyses revealed that serum irisin, HD vintage and age were significant independent determinant factors for vascular calcification in HD patients. Conclusion: Our results are the first to provide a clinical evidence of the association between serum irisin and vascular calcification in HD patients. Lower irisin levels, long-term hemodialysis and old ages are independent risk factors in HD patients.

Irisin and Volume Overload are Associated with Protein Energy Wasting in Peritoneal Dialysis Patients

Background/Aims: Protein energy wasting (PEW) is a common medical phenomenon that is observed in maintenance dialysis patients. PEW also increases morbidity and mortality of these patients. Its pathogenesis is unclear. We hypothesize that serum irisin levels and volume overload may induce PEW in peritoneal dialysis (PD) patients. The aim of this study is to measure serum irisin levels, evaluate volume status of PD patients, and study their correlations with PEW in PD patients. Methods: This study is a cross-sectional study with 160 PD patients from the PD center of Peking University Third Hospital and 35 healthy control subjects. PD patients were divided into PEW group and non-PEW group according to PEW diagnosis criteria. Serum irisin concentrations were measured by ELISA. Volume overload status (volume overload is defined as overhydration value ≥2 liters) of PD patients was analyzed by bioelectrical impedance. Results: The serum irisin levels were significantly lower in PD patients compared with those of the controls (113.2±11.8 ng/ml vs. 464.2±37.4 ng/ml, P<0.01). The serum irisin levels were lower in PD patients with PEW than those of the patients without PEW (106.5±15.2 ng/ml vs. 117.4±17.6 ng/ml, P<0.01). PEW is more prevalent in patients with volume overload than patients without volume overload (62.5% vs. 43.1%, x2=5.756, P=0.016); however, no direct relationship was found between irisin levels and volume overload status. The independent influencing factors of PEW were serum irisin, serum albumin, and volume overload. Conclusion: Our results are the first to provide clinical evidence of the association between serum irisin, volume overload, and PEW in PD patients. PEW may inhibit the release or synthesis of irisin from skeletal muscles, and volume overload may aggravate PEW in PD patients.

Experiences with Establishing the First Self-Care Hemodialysis Program in a Hospital in Mainland China

There has never been a home hemodialysis (HHD) program or self-care hemodialysis (SC-HD) program in Mainland China, and it may be plausible starting from an SC-HD program. This study describes the systems for, and the initial results of, starting an SC-HD program. A program for SC-HD was instituted at the Peking University Third Hospital. A working group had designed the patient education program and water quality assurance. The patient’s education program was established, which consisted of a handbook and a video for training. In May 2009, two patients were recruited and trained for HD. They were adequately dialyzed with satisfactory Kt/V, both the patients could perform all of the self-care procedures after training for 12 weeks. More difficult procedures, such as the self-cannulation, were successfully handled. Significant improvement was found in six of the eight short form (SF)-36 health scales after 6 months for SC-HD treatment. For the past year, there were no severe complications resulting from SC-HD. In summary, our first SC-HD program in Mainland China is feasible and safe. It promotes rehabilitation, increases self-esteem, and improves health-related quality of life. It is also a first attempt for starting an HHD program.