Markers of Oxidative Stress, Inflammation, and Endothelial Dysfunction in Diabetic and Nondiabetic Patients with Chronic Kidney Disease on Peritoneal Dialysis

Chronic kidney disease (CKD) is a low-grade inflammatory state which is accom-panied by elevated markers of oxidative stress, inflammatory, and endothelial dysfunction in patients on peritoneal dialysis (PD). These represent a key triad for the development and progression of atherosclerosis. The present study assessed the markers of oxidative stress, inflammatory and endothelial dysfunction in diabetic and non-diabetic CKD patients on PD. A cross-sectional study was undertaken on 100 CKD patients on PD, of whom 52 patients were nondiabetic and 48 were diabetic patients. Blood samples were estimated for malondialdehyde (MDA) and ferric reducing ability of plasma (FRAP) as markers of oxidative stress; interleukin (IL)-6, high-sensitivity C-reactive protein (hs-CRP), and fibrinogen as inflammatory markers; and markers of endothelial dysfunction such as nitric oxide (NO), carotid wall intimal medial thickness (CIMT), and number of plaques, among others. The MDA levels increased and FRAP levels decreased in both diabetic and nondiabetic CKD patients on PD. The levels of IL-6, hs-CRP, fibrinogen, NO, CIMT, and the number of plaques were significantly higher in diabetic patients than in nondiabetic CKD patients on PD. The lipid profile was significantly atherogenic in diabetic patients compared with nondiabetics CKD patients. The results showed increased oxidative stress, inflammation, and endothelial dysfunction in diabetic patients compared with nondiabetics CKD patients on PD.

Influence of Residual Renal Function in Carotid Modeling as a Marker of Early Atherosclerosis in Dialysis Patients

Atherosclerosis is frequently present in patients with chronic kidney disease (CKD) treated with dialysis. We evaluated the association between residual renal function (RRF), phosphate level, inflammation and other risk factors in carotid modeling as a marker of early atherosclerosis in peritoneal dialysis (PD) compared with hemodialysis (HD) patients. We studied 39 stable PD and 53 HD patients on renal replacement therapy (RRT) for 3 to 36 months duration. B-mode ultrasonography was used to determine carotid artery intima media thickness (CIMT). We classified patients with atherosclerosis if they have CIMT >10 mm and or presence of plaque. Out of our total dialysis population studied of 92 patients, 16.3% were diabetics and 57.6% were on hemodialysis. Expectedly, PD patients had a higher RRF (P < 0.001), 24 h urine volume (P < 0.001); C-reactive protein (P = 0.047), and a lower serum phosphate (P = 0.01), PTH (P < 0.05), alkaline phosphatase (P < 0.05), and albumin levels (P < 0.001) compared to hemodialysis patients. Atherosclerosis was found in 66.3% of patients and in 100% of a diabetic population. There was no significant difference in the presence of atherosclerosis between PD and HD patients [56.4 vs 73.6% HD, respectively]. Multiple regression analysis showed age, diabetes, HD modality, RRF, phosphate, PTH and pulse pressure as independent parameters associated with atherosclerosis. Apart from the traditional risk factors like age and diabetes, our study showed a link of atherosclerosis with metabolic abnormalities secondary to renal failure. We demonstrated a novel, independent association between RRF and atherosclerosis, underlining the importance of preservation of the RRF in dialysis patients.

Fibroblast growth factor-23 levels are associated with uric acid but not carotid intima media thickness in renal transplant recipients

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of mortality in chronic kidney disease (CKD) patients. Fibroblast growth factor-23 (FGF-23) is associated with atherosclerosis and cardiovascular mortality in CKD patients and healthy subjects. However, data in renal transplant recipients (RTR) are scarce. We aimed to determine factors associated with FGF-23 and to explore its relationship to atherosclerosis.

METHODS

Forty-six patients and 44 controls were included. FGF-23 was measured from plasma. Carotid intima media thickness (CIMT) was evaluated ultrasonographically.

RESULTS

Patients had higher waist circumference (WC; 92.2 ± 14.9 vs 85.3 ± 11.0 cm; P < .05), glucose (99.8 ± 17.2 vs 90.3 ± 6.5 mg/dL; P < .01), creatinine (1.43 ± 0.6 vs 0.86 ± 0.1 mg/dL; P < .01), triglyceride (160.4 ± 58.9 vs 135.6 ± 59.8 mg/dL; P < .05), white blood cells (WBC; 7938.6 ± 2105.2 vs 6715.7 ± 1807.5 WBC/mm(3); P < .01), ferritin (217.0 ± 255.8 vs 108.3 ± 142.4 ng/mL; P < .05), uric acid (6.5 ± 1.6 vs 4.7 ± 1.3 mg/dL; P < .01), C-reactive protein (CRP; 8.2 ± 18.2 vs 5.3 ± 7.9 mg/L; P < .01), parathyroid hormone (PTH; 89.7 ± 59.2 vs 44.1 ± 16.7 pg/mL; P < .01), and alkaline phosphatase (ALP; 162.5 ± 86.6 vs 74.2 ± 21.9 U/L; P < .01). FGF-23 was higher in patients (11.7 ± 7.2 vs 9.6 ± 6.8 pg/mL; P < .05). CIMT was similar (0.58 ± 0.09 vs 0.57 ± 0.1 mm; P > .05). WC, creatinine, and uric acid were positively correlated with FGF-23, whereas albumin showed negative correlation. On multivariate analysis only creatinine and uric acid were determinants of FGF-23.

CONCLUSION

FGF-23 levels are associated with uric acid in RTR. Larger studies are needed to confirm this finding.

Effects of dialysis solution on the cardiovascular function in peritoneal dialysis patients

Objective Peritoneal dialysis (PD) patients have an increased cardiovascular burden. In this study, we aimed to compare certain PD solutions (Physioneal(®) and Dianeal(®)) in terms of the ambulatory blood pressure, echocardiographic parameters (ECHO), carotid atherosclerosis, endothelial function and serum asymmetric dimethylarginine (ADMA) level. Methods A total of 45 PD patients were enrolled in this prospective randomized controlled study: 23 patients in the Dianeal(®) group and 22 patients in the Physioneal(®) group. Ambulatory blood pressure measurements, echocardiography, carotid artery intima-media thickness measurements and flow mediated dilatation (FMD) and ADMA values were obtained at baseline and 12 months. Results The baseline parameters were similar between the groups with respect to the echocardiographic parameters, 24-hour ambulatory blood monitoring measurements and ADMA and FMD levels. All 24-hour blood pressure monitoring measurements, except for the average daytime systolic blood pressure, were significantly decreased in both groups at the first year. In the Physioneal(®) group, a significant decrease was observed with regard to the ADMA levels. Considering the FMD values, significant augmentation was seen at the end of the first year in both groups. Improvements in the FMD measurements were prominent in the Physioneal(®) group; however, this finding was not statistically significant. Conclusion The use of solutions with a neutral pH in PD patients results in decreased ADMA levels, which may be an important contributor to reductions in the incidence of cardiovascular events and deaths in this population.

Assessment of endothelial dysfunction in Asian Indian patients with chronic kidney disease and changes following renal transplantation

BACKGROUND

Endothelial dysfunction may explain increased cardiovascular risk in patients with chronic kidney disease (CKD).

METHODS

Brachial artery was imaged during reactive hyperemia (endothelium-dependent, flow-mediated dilatation, FMD) and during glyceryl trinitrate-mediated dilatation (nitroglycerine-mediated dilatation, NMD, endothelium-independent) in 108 patients with CKD and three months following renal transplantation (RT) in 60 of them.

RESULTS

Patients with CKD had significantly lower FMD vs. controls (9.1% vs. 18.3%, p < 0.001) while NMD was comparable (19.8% vs. 21.8%, p = ns). Impaired FMD (<4.5%) was observed in 26.8% patients with CKD and was more common in those on hemodialysis (HD; 28.4% vs. 15.4%) vs. those not on dialysis. FMD for patients with glomerular filtration rate (GFR) 15-60 vs. <15 mL/min/1.73 m(2) was 12.9% and 8.8% (p = 0.05; respectively -29% and -52% lower vs. controls), indicating reduced FMD with increasing CKD severity. There was +72% increase in FMD following RT (9.1 to 15.7%, p < 0.001) while mean NMD was unchanged. Following RT, only 3.3% had impaired FMD.

CONCLUSIONS

Patients with CKD have endothelial dysfunction as evidenced by reduced FMD. Decreased FMD indicating worsening endothelial function was noted with increasing severity of CKD. Within three months of RT, there was significant improvement in FMD, while NMD values did not change.

Impact of hypertension on various markers of subclinical atherosclerosis in early type 2 diabetes

Background

Presence of Diabetes Mellitus increases the risk of subclinical atherosclerosis. In this study was aimed to determine the influence of hypertension (HTN) on surrogate markers of atherosclerosis in a population of patients with early type 2 diabetes.

Methods

125 diabetic subjects drawn from Dr. Shariati outpatient’s clinic list and 153 non- diabetic subjects who were the relatives in law of diabetic participants were recruited. Participants with type 2 diabetes were free of clinical evidence of cardiovascular disease and renal involvement. Two groups of diabetic and control were further divided into two subgroups of hypertensive (known case of HTN or blood pressure ≥140/90 mmHg) and normotensive, and anthropometric characteristics, metabolic biomarkers as well as markers of subclinical atherosclerosis including Carotid intima media thickness (CIMT), flow mediated dilation (FMD) and Ankle Brachial Index (ABI) were measured.

Results

Diabetic group with a mean age of 49.9 ± 7.5 years had significantly higher CIMT (0.64 ± 0.14 vs 0.76 ± 0.19, p = 0.001) and lower FMD (16.5 ± 8.1 vs 13.3 ± 7.1, p = 0.003) and ABI (1.2 ± 0.1 vs 1.1 ± 0.1, p = 0.01) than control with mean age of 52.9 ± 10.1 years. 34% of control and 59.2% of diabetic were hypertensive. Fasting blood sugar, insulin levels and calculated insulin resistance index of HOMA IR. of hypertensive subjects were higher than normotensive subjects in both groups of diabetic and non-diabetic. Similar pattern was presented for measured inflammatory mediators of hs-CRP and IL-6. Among subclinical atherosclerosis markers, only CIMT was significantly different between hypertensive and normotensive subjects in both groups. In adjusted linear regression analysis, a constant significant association existed between age and CIMT, ABI and FMD in non-diabetic, while in diabetic, age only correlated with CIMT and not the other two markers. In multiple regression model, HTN was recognized as a risk factor for increasing CIMT (OR = 2.93, 95% CI = 1.03-8.33, p = 0.04) but not attenuating FMD or ABI.

Conclusions

Since FMD and CIMT may measure a different stage of subclinical atherosclerosis in diabetic patients, influence of HTN on these markers might be different.

Impact of peritoneal dialysis treatment on arterial stiffness and vascular changes in diabetic type 2 and nondiabetic patients with end-stage renal disease

Diabetes mellitus (DM) is the leading cause of the end-stage renal disease (ESRD). Vascular diseases are the most common cause of morbidity and mortality in the chronic kidney disease. The aim of this study was to analyze the impact of peritoneal dialysis (PD) treatment on morphologic and hemodynamic vascular parameters of carotid arteries in diabetic type 2 and nondiabetic patients with ESRD during the period of one year after the start of PD treatment using ultrasonography of carotid arteries and their relation on uremia and PD inherent factors. Mean intima-media thickness, plaque score, peak systolic velocity, end-diastolic velocity, and carotid diameter significantly decreased 12 months after PD treatment start in both groups. Significant reduction in median serum endothelin-1 concentration after 12 months on PD treatment was observed in the group of patients with DM (7.6–5.9 pg/mL) and also in group of patients without DM (3.6–3.3 pg/mL). Also median nitric oxide concentration significantly increased after 12 months on PD compared to baseline levels both in patients with DM (25.0–34.3 μmol/L) as was observed in patients without DM (49.6–56.5 μmol/L). PD treatment, with the regulation of these vasoactive molecules and other vascular risk factors, significantly contributes to vascular remodeling, especially in DM patients.

Fibroblast growth factor-23 levels are associated with vascular calcifications in peritoneal dialysis patients

BACKGROUND

The aim of the study was to assess the relationship between fibroblast growth factor-23 (FGF-23) and vascular calcifications (VC) in peritoneal dialysis (PD) patients.

METHODS

A cross-sectional study was performed in 55 PD patients who underwent pelvic X-ray to assess for VC. Patients with and without linear calcifications were recorded.

RESULTS

Fifteen patients (27.3%) had linear calcifications on pelvic X-ray. FGF-23 levels were higher in patients with VC (299.5 (30.4-2,410.0) vs. 74.4 (14.8-1,030) pg/ml, p < 0.01). Diabetic patients had lower FGF-23 values (43.2 (14.9-134.0) vs. 103.5 (14.8-2,410) pg/ml, p < 0.01). Patients with residual renal function (RRF) had lower FGF-23 levels (70.6 (14.8-513) vs. 179.5 (30.4-2,410) pg/ml, p = 0.06); however, this did not reach statistical significance. FGF-23 levels, age, creatinine, Ca, dialysis duration and HbA1c were positively correlated with VC, whereas RRF, Ca intake and ALP were negatively associated. Multivariate logistic analysis confirmed FGF-23 levels, age, dialysis duration and RRF to be associated with VC.

CONCLUSIONS

FGF-23 levels are associated with VC in PD patients. Further studies are needed to clarify whether it is simply a marker or a potential factor. It may prove to be an important therapeutic target for VC management.

Visceral fat thickness is associated with carotid atherosclerosis in peritoneal dialysis patients

Visceral fat has been known to associate with atherosclerosis, inflammation, and insulin resistance. However, the influence of visceral fat on cardiovascular disease (CVD) in peritoneal dialysis (PD) patients has never been elucidated. We investigated whether visceral fat thickness (VFT) has a predictive role in carotid atherosclerosis determined by carotid intima-media thickness (cIMT) in PD patients. A cross-sectional study was undertaken in 88 prevalent PD patients. BMI and waist circumference (WC) were measured as anthropometric indexes of obesity. VFT and subcutaneous fat thickness (SFT) were determined by sonographic measurement of abdominal fat. Carotid atherosclerosis was defined as increased cIMT (>1.0 mm) or presence of plaque. Thirty-two (36.3%) patients had carotid atherosclerosis. Patients with carotid atherosclerosis showed significantly higher VFT, BMI, and WC. In univariate logistic analysis, BMI, WC, and VFT except SFT were significant risk factors of carotid atherosclerosis. However, multivariate analysis revealed VFT was an independent factor associated with carotid atherosclerosis after adjusting for demographic, biochemical parameters, and anthropometric indexes (per 1 mm increase, odds ratio (OR) = 2.294, 95% confidence interval: 1.048-5.021, P = 0.038). When the patients were divided into three groups according to VFT, log high sensitivity C-reactive protein (hs-CRP), and homeostasis model assessment-insulin resistance (HOMA(IR)) were both higher in the third tertile compared to other tertiles. In conclusion, VFT, not SFT, is independently associated with carotid atherosclerosis in PD patients. Therefore sonographic measurement of VFT could be useful to stratify the risk of cardiovascular disease in PD patients.

Vascular health, systemic inflammation and progressive reduction in kidney function; clinical determinants and impact on cardiovascular outcomes

INTRODUCTION

Systemic inflammation, endothelial dysfunction and arterial thickening contribute to the elevated cardiovascular risk of dialysis patients. However, the course of these derangements and their relative contribution to the cardiovascular risk of nondialysed chronic kidney disease (CKD) are scarcely investigated.

METHODS

Flow-mediated dilatation (FMD) and intima-media thickness (IMT) were assessed in 304 nondialysed CKD patients Stages 1-5 (mean age 46 ± 12 years, 158 men), together with routine biochemical measurements, C-reactive protein (CRP) and insulin resistance. Patients were then followed for time-to-event analysis of cardiovascular outcomes (fatal and nonfatal).

RESULTS

CRP and IMT increased, while FMD decreased in parallel with estimated glomerular filtration rate (eGFR) decline (P < 0.001 for all). CRP and intact parathormone, as well as eGFR, appeared as strong determinants of FMD and IMT in multivariate analyses. After a median follow-up of 41 (range 6-46) months, 30 fatal and 59 nonfatal cardiovascular events occurred. In univariate analysis, FMD, IMT and CRP were significant predictors of outcome. In a multivariate Cox model excluding IMT, both FMD [hazard ratios 0.52 (95% confidence intervals 0.37-0.73) per %] and CRP [1.07 (1.03-1.11) per mg/L] predicted cardiovascular outcomes independently of confounders. In a model excluding FMD, only CRP (and not IMT) was a significant predictor.

CONCLUSIONS

Endothelial dysfunction, arterial thickening and inflammation occur in parallel with the decline in eGFR, contributing to the increased cardiovascular risk of nondialysed CKD. Our results support the use of FMD over IMT measurements to monitor nondialysed CKD patients at risk.

Endothelial dysfunction, inflammation and atherosclerosis in chronic kidney disease--a cross-sectional study of predialysis, dialysis and kidney-transplantation patients

BACKGROUND

Cardiovascular morbidity and mortality are high in chronic kidney disease (CKD) patients compared to the general population. Systemic inflammation may contribute to endothelial dysfunction and accelerated atherosclerosis in CKD patients. We assessed the relationship among, endothelial dysfunction, early atherosclerosis and inflammation in predialysis, dialysis and post kidney-transplantation CKD patients.

METHODS AND RESULTS

We studied 76 consecutive CKD patients; 38 predialysis, 18 haemodialysis and 22 kidney-transplant patients. A group of 65 age and gender matched controls were also studied. In both patients and controls, high-sensitivity C-reactive protein (CRP) levels, systemic endothelial function (brachial artery flow mediated dilation, FMD,%) and carotid artery intima-media thickness (IMT, mm) were measured. CKD patients had increased CRP levels (3.7 [1.0-6.0]mg/L vs 1.0 [0.5-2.1]mg/L; p<0.001), reduced FMD (2.2 [1.0-4.0] vs 5.6 [4.4-7.1]; p<0.001) and increased IMT (0.82±0.21 vs 0.67±0.16; p<0.001) values compared to controls. In CKD patients, a significant negative correlation was found between CRP levels and FMD responses (r=-0.51; p<0.001) while a significant positive correlation was found between CRP and IMT values (r=0.50; p<0.001). Increased CRP levels were an independent predictor of both abnormal FMD and IMT after adjusting for age, systolic and diastolic BP and total cholesterol. Compared with predialysis and kidney-transplant patients, haemodialysis subjects had significantly lower FMD and higher CRP and IMT values.

CONCLUSIONS

CKD patients taken together have a higher inflammatory status compared to controls. Abnormal FMD responses and IMT values are more commonly found in dialysis patients. Our findings suggest that endothelial dysfunction and atherosclerotic changes correlate with inflammation.

Profiles of inflammatory markers and lipoprotein subclasses in patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) often have inflammation and dyslipidemia that accelerate to atherosclerosis. This study aimed to evaluate chronic inflammation and dyslipidemia in CAPD patients.

METHODS

We measured inflammatory markers and lipoprotein subclasses in 20 CAPD patients (12 men and 8 women, aged 59.5 ± 9.9 y) and 20 gender-matched controls. Lipoproteins were separated by high-performance liquid chromatography (HPLC) using an anion-exchange column.

RESULTS

High-sensitivity C-reactive protein and serum amyloid A protein (SAA) were higher among CAPD patients vs. controls (1.6 ± 2.2 vs. 0.8 ± 1.2 mg/l, p<0.05; 11.9 ± 12.8 vs. 4.5 ± 2.4 mg/l). HPLC analysis revealed that chylomicron, VLDL, and IDL cholesterol levels were higher among CAPD vs. controls. In contrast, HDL cholesterol was lower among CAPD patients vs. controls. In the subgroup analysis, SAA levels were significantly lower among patients receiving CAPD for >3 y than among controls. However, IDL cholesterol was consistently higher among CAPD patients vs. controls.

CONCLUSIONS

CAPD patients have chronic inflammation and dyslipidemia. IDL cholesterol is the only lipoprotein subclass that is consistently elevated regardless of CAPD duration. More attention should be paid to dyslipidemia in the management of the CAPD patients.