Strong association between malnutrition, inflammation, and atherosclerosis in chronic renal failure

Dialysate as Food: Combined Amino Acid and Glucose Dialysate Improves Protein Anabolism in Renal Failure Patients on Automated Peritoneal Dialysis

Protein-energy malnutrition as a result of anorexia frequently occurs in dialysis patients. In patients who are on peritoneal dialysis (PD), dialysate that contains amino acids (AA) improves protein anabolism when combined with a sufficient oral intake of calories. It was investigated whether protein anabolism can be obtained with a mixture of AA plus glucose (G) as a source of proteins and calories during nocturnal automated PD (APD). A random-order cross-over study was performed in eight APD patients to compare in two periods of 7 d each AA plus G dialysate obtained by cycler-assisted mixing of one bag of 2.5 L of AA (Nutrineal 1.1%, 27 g of AA) and four bags of 2.5 L of G (Physioneal 1.36 to 3.86%) versus G as control dialysate. Whole-body protein turnover was determined using a primed continuous infusion of L-[1-13C]leucine, and 24-h nitrogen balance studies were performed. During AA plus G dialysis, when compared with control, rates of protein synthesis were 1.20 +/- 0.4 and 1.10 +/- 0.2 micromol/kg per min leucine (mean +/- SD), respectively (NS), and protein breakdown rates were 1.60 +/- 0.5 and 1.72 +/- 0.3 micromol/kg per min (NS). Net protein balance (protein synthesis minus protein breakdown) increased on AA plus G in all patients (mean 0.21 +/- 0.12 micromol leucine/kg per min; P < 0.001). The 24-h nitrogen balance changed by 0.96 +/- 1.21 g/d, from -0.60 +/- 2.38 to 0.35 +/- 3.25 g/d (P = 0.061, NS), improving in six patients. In conclusion, APD with AA plus G dialysate improves protein kinetics. This dialysis procedure may improve the nutritional status in malnourished PD patients.

Nutritional and Inflammatory Markers in the Prediction of Mortality in Chinese Hemodialysis Patients

BACKGROUND/AIMS

The prevalence of cardiovascular disease and mortality rate is relatively low in Chinese dialysis patients. This study aimed to evaluate the predictive value of nutritional and inflammatory markers in Chinese hemodialysis patients.

METHODS

A total of 158 patients (70 men and 88 women, age 59.9 +/- 13.2 years) were studied. Nutritional and inflammatory markers, including subjective global assessment (SGA), insulin-like growth factor-1, albumin, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, serum amyloid A (SAA), and C-reactive protein (CRP), were measured. These patients were followed up until April 2004 (36 months) to determine the incidence and causes of death.

RESULTS

SGA (p = 0.001), IL-1beta (p = 0.032), SAA (p = 0.031), IL-6 (p = 0.001) and CRP (p < 0.001) were found to be significant predictors of mortality. After adjusting with age, sex, diabetes, coronary artery disease, Kt/Vurea, and duration on dialysis, CRP (odds ratio = 4.58; p = 0.038) and SGA (odds ratio = 6.57; p = 0.004) remained the independent predictors of mortality. The adjusted mortality rate was highest for patients with a high CRP level and malnutrition (assessed by SGA).

CONCLUSIONS

SGA and CRP levels are the most significant predictors of mortality in Chinese dialysis patients. Chinese dialysis patients with a high CRP level tend to be at higher risk of mortality only if they are malnourished.

C-reactive protein as an independent risk factor for carotid atherosclerosis in hemodialysis patients

C-reactive protein is a known risk factor for cardiovascular diseases, but the association of CRP with the early phase of atherosclerosis has been insufficiently investigated. The aim of the present study was to investigate the relationship between CRP and indicators of subclinical atherosclerosis in hemodialysis patients. Intima-media thickness, lumen-diameter and cross-sectional intima-media area (CSIM area) of the common carotid artery were established using B-mode ultrasound imaging in 43 HD patients and 21 age- and gender-matched healthy controls. CSIM area and LD were significantly higher in HD patients compared with control subjects. Inflammation (CRP> 10 mg/l) was present in 58.1% of HD patients and was associated with higher values of all ultrasonographic markers of atherosclerosis, as well as higher prevalence of atherosclerotic vascular diseases. Higher CSIM area was associated with elevated CRP level (r=0.619, p=0.000), advanced age (R=0.704, p=0.005) and smoking habits (R=0.742, p=0.039). Results of our investigation support the concept on key role of inflammation in the development of atherosclerosis in HD patients.

Dialysis water as a determinant of the adequacy of dialysis

Hemodialysis patients are exposed to large volumes of water in the form of dialysate. Contaminants from the dialysate may cross the dialyzer membrane into the blood and have the potential to compromise the adequacy of dialysis. Several chemicals found commonly in drinking water have long been known to be toxic to hemodialysis patients. More recently, it has become apparent that even low levels of bacterial products in dialysate may adversely impact dialysis adequacy through their ability to stimulate an inflammatory response. Minimum levels of water and dialysate quality have been recommended to protect patients from chemical and microbiologic contaminants. Complying with these recommendations requires an appropriately designed water purification and distribution system, combined with a surveillance program designed to maintain dialysate quality.

Cognitive function in dialysis patients

There are few detailed studies of cognitive function in dialysis patients. However, appreciating the prevalence and risk factors for cognitive impairment is important because cognitive impairment may decrease an individual's quality of life, increase resource utilization, and result in suboptimal medical care because of difficulty following caregiver recommendations. Cognitive impairment also is likely to become more of a problem as the dialysis population ages. In this review, we argue that cerebrovascular disease is an important cause of cognitive impairment in dialysis patients and discuss risk factors specific for vascular disease, as well as other factors that may influence cognitive function. We describe the structural brain abnormalities frequently seen in dialysis patients and the specific neurocognitive changes noted in prior studies. We explore potential measures to reduce cognitive impairment in this population. We conclude that additional research is needed in this area.

C-Reactive Protein Levels in Patients on Maintenance Hemodialysis: Reliability and Reflection on the Utility of Single Measurements

BACKGROUND

Single C-reactive protein (CRP) values have been associated with death and cardiovascular disease in dialysis patients. We prospectively obtained multiple CRP values in stable patients, hypothesizing that values would remain stable in the absence of disease and that a single CRP value would be a reliable marker of risk.

METHODS

Four CRP values per week for three consecutive weeks were obtained in 10 clinically stable patients receiving conventional HD. Using prespecified cutoffs of 2.2 and 4.4 mg/l, the frequency of risk misclassification relative to the lowest CRP value obtained was determined. Within and between patient variability was also calculated.

RESULTS

The median age was 54 years, and the average duration of dialysis was 41 months. Nine out of ten patients had at least one abnormal CRP value (>2.2 mg/l), six had all values elevated, and seven had an abnormal median CRP. The overall coefficient of reliability was 0.63 (95% CI 0.42-0.87). The misclassification rate varied with cutoff, and ranged from 0-83% and 0-58% using upper limit of normal (ULN) and twice ULN, respectively. The within patient variability was 0.37 for the entire cohort, and 0.33 when three patients with intercurrent acute inflammation were excluded.

CONCLUSIONS

CRP exhibits short term variability in HD patients, resulting in a risk of misclassification depending on sampling time and chosen cutoff point. Single CRP values must be interpreted with caution, and multiple measurements, or use of other biomarkers, should be considered.

TNF Alpha-308 Genotype and Renin-Angiotensin System in Hemodialysis Patients: An Effect on Inflammatory Cytokine Levels?

BACKGROUND

Renin-angiotensin system (RAS) was suggested to modulate inflammatory cytokine production. Angiotensin II was consistently shown to increase production of tumor necrosis factor alpha (TNF-alpha). However, inflammatory cytokines and RAS were modulated by genetic polymorphisms such as TNF-alpha-308 G > A and angiotensin-converting enzyme (ACE) I/D gene polymorphisms. The aim of this study was to investigate the effects of ACE and TNF-alpha genotypes on inflammatory cytokines in hemodialysis (HD) patients.

METHODS

ACE I/D and TNF-alpha-308 G > A genotypes, pre- and postdialysis plasma renin activity (PRA), serum ACE, interleukin-1 beta (IL-1beta), and TNF-alpha levels were determined in 22 HD patients.

RESULTS

Predialysis serum ACE activity is correlated with TNF-alpha (r = 0.63; P = 0.01), and PRA was correlated with IL-1beta levels (r = 0.49; P = 0.02). Pre/postdialysis IL-1beta and TNF-alpha were similar in DD and II/ID ACE genotypes. Predialysis TNF-alpha and IL-1beta (32.4 +/- 5; 35.1 +/- 4.2 vs. 28.1 +/- 3.7; 26.5 +/- 6.2 pg/mL; P < 0.05) and postdialysis TNF-alpha levels (30.4 +/- 1.4 vs. 28.4 +/- 0.82 pg/mL; P < 0.05) were significantly higher in TNF1/2 than TNF1/1 patients.

CONCLUSION

ACE and TNF-alpha-308 G > A (1/2) gene polymorphisms may contribute to modulation of proinflammatory cytokine production and hence chronic inflammation in HD patients.

Antioxidant therapy in uremia: evidence-based medicine?

Because of correlations between cardiovascular disease, inflammation, and renal failure, many investigators are pursuing nontraditional risk factors and therapies in order to reduce cardiovascular morbidity and mortality in the end-stage renal disease (ESRD) population. Despite the disappointing lack of clinical effects with antioxidative therapies seen in large studies of the general population, some studies suggest a diminished cardiovascular risk in individuals with renal failure. This expanding new line of evidence is promising as a method to help alleviate the more than 20-fold increase in risk of cardiovascular events in the ESRD population. Most of the current available studies have evaluated laboratory or physiologic endpoints, such as endothelial function and measures of oxidative burden, and have evaluated relatively small numbers of patients. However, it is currently premature to initiate widespread clinical therapy with antioxidants. Further investigation in this area should be supported to see if reported benefits can be duplicated in more widespread study populations, and to more accurately define the most appropriate choice of therapy, mode of therapy, and dose.

Use of Ultrapure Dialysate in Reduction of Chronic Inflammation during Hemodialysis

Chronic inflammation contributes to the pathogenesis of several complications of hemodialysis therapy. It is thought that backfiltration of bacteria-derived contaminations during dialysis may induce a chronic inflammatory state. High-sensitivity C-reactive protein (hs-CRP) is one of the tools which can take a hold on such a chronic inflammatory condition. We examined the effect of ultrapure dialysate which contributes to chronic inflammation with hs-CRP and tried to reduce endotoxin (ET) levels at the end of the dialysate from 70 EU/l to <1.0 EU/l (ultrapure dialysate). Other dialysis conditions, except ET level, were fixed. We investigated the hs-CRP of 23 patients receiving regular dialysis before the use of ultrapure dialysate and 1 year after use of it prospectively. The data showed a significant decrease in the median value of the hs-CRP from 0.16 to 0.07 mg/dl (p < 0.05). The value of serum beta(2)-microglobulin decreased from 33.2 to 28.4 mg/dl (p < 0.01) and the hemoglobin level increased from 10.0 to 11.0 g/dl (p < 0.05). These results indicate that even a dialysate containing 70 EU/l of ET level may induce a chronic inflammatory state. hs-CRP is a very useful marker of chronic inflammation and the use of ultrapure dialysate is necessary to improve a chronic inflammatory state. The targeted ET level at the end of the dialysate should be set at < or = 1.0 EU/l.

Inflammation and resistance to treatment with recombinant human erythropoietin

Despite an increase in the use and average dose of recombinant human EPO (rh-EPO) over the last 15 years, a substantial percentage of patients still do not achieve hemoglobin targets recommended by international guidelines. The definition of rh-EPO resistance has been introduced to identify those patients in whom the target hemoglobin level is not attained despite a greater-than-usual dose of erythropoietin-stimulating agent (ESA). In recent years, increasing attention has been paid to the relationship between dialysis, increased inflammatory stimulus, malnutrition, and ESA response. About 35% to 65% of hemodialysis patients show signs of inflammation that could be a cause of anemia through the suppression of bone marrow erythropoiesis by a number of cytokines. A large proportion of chronic kidney disease patients also have protein-energy malnutrition and wasting; low serum albumin levels, together with other more specific nutritional markers, are predictors of rh-EPO response. A diminished nutritional state could then be a feature of patients who are resistant to ESA treatment, with malnutrition probably being a consequence of a chronic inflammatory state. Starting from the hypothesis that anemia, partially attributable to a reduced response to ESA, could be the link among malnutrition, inflammation, and the poor outcome of chronic kidney disease patients, we designed a multicenter observational study, the Malnutrition-Inflammation-Resistance-Treatment Outcome Study (MIRTOS), aimed at evaluating the impact and possible causes of resistance to ESA in a large sample of hemodialysis patients. We hope the results of MIRTOS will represent a step forward toward a better understanding of the factors influencing the response to ESA in hemodialysis patients.

Preventing cardiovascular outcome in patients with renal impairment: is there a role for lipid-lowering therapy?

Patients with chronic kidney disease (CKD), ranging from modest renal impairment to dialysis and transplant, have an increased risk for cardiovascular disease (CVD). Patients with CKD have both traditional and non-traditional risk factors for CVD. The role of lipids as risk factors for CVD in these populations has not been firmly established. In a recent prospective controlled trial, it was established that atherogenic lipids are indeed strong risk factors for CVD in renal transplant recipients, and that treatment with a HMG-CoA reductase inhibitor reduced the incidence of cardiac death and myocardial infarction. For patients receiving dialysis, the association between serum lipid levels and cardiovascular outcome is uncertain and there is no evidence from controlled trials that lipid-lowering therapy does have a beneficial effect on cardiovascular outcome in these patients. Atherogenic lipids are probably a risk factor for patients with mild or moderate CKD, and five subgroup analyses have indicated a favorable effect of lipid-lowering therapy on cardiovascular outcome, although we still lack prospective controlled trials in these patients. CVD in patients with CKD has been a neglected area of research.

The influence of obesity on the development and survival outcomes of chronic kidney disease

The prevalence of obesity, defined as a body mass index (BMI) greater than 30 kg/m2 , has more than doubled in many Western countries over the past 2 decades and has become a major public health challenge. This epidemic of obesity in developed countries has been matched closely by alarming increases in the incidence of diabetes mellitus, hypertension, chronic kidney disease (CKD), and cardiovascular disease. However, the exact role that increased body size plays in the development of nephropathy and its subsequent contribution to cardiovascular morbidity and mortality remain unclear. For example, whether obesity per se is a risk factor for CKD independent of diabetes mellitus and hypertension is uncertain. Moreover, in patients with end-stage kidney disease, strong evidence suggests that obesity may paradoxically enhance patient survival. This review will focus on the evidence for obesity as an independent risk factor for the development and progression of CKD and as a paradoxical survival factor in patients with end-stage kidney failure. Possible mechanisms underlying these observed associations will be discussed.

Evaluation of handgrip strength as a nutritional marker and prognostic indicator in peritoneal dialysis patients

BACKGROUND

Serum albumin has limitations as a nutritional marker in patients undergoing peritoneal dialysis (PD) in that it is affected by inflammation, systemic disease, overhydration, and urinary and dialysate protein loss. Handgrip strength is a simple, easily performed bedside test that has been shown to correlate with lean body mass in patients close to inception of dialysis.

OBJECTIVE

We evaluated the associations of handgrip strength with other clinical factors and examined its relations with mortality and cardiovascular death in PD patients.

DESIGN

We prospectively enrolled 233 chronic PD patients and assessed handgrip strength and other variables at baseline and then followed the patients for a mean (+/-SD) of 30 +/- 14 mo.

RESULTS

Baseline handgrip strength was significantly associated with age, sex, height, diabetes, residual glomerular filtration rate (GFR), and hemoglobin but not with C-reactive protein (CRP). After adjustment for age, sex, and height, handgrip strength was most strongly correlated with lean body mass on the basis of creatinine kinetics (r = 0.334, P < 0.001), followed by serum albumin and subjective global assessment. Both men and women who died had lower handgrip strengths than did those who remained alive (P < 0.001). After control for age, sex, diabetes, atherosclerotic vascular disease, GFR, hemoglobin, CRP, and serum albumin, greater handgrip strength was predictive of lower all-cause [hazards ratio (HR): 0.95 (95% CI: 0.92, 0.99); P = 0.005] and cardiovascular [HR: 0.94 (0.90, 0.98); P = 0.004] mortality.

CONCLUSIONS

Handgrip strength not only is a marker of body lean muscle mass but also provides important prognostic information independent of other covariates, including CRP and serum albumin. Our data suggest that handgrip strength may be used in conjunction with serum albumin as a nutrition-monitoring tool in patients undergoing PD.

LDL-apheresis improves peripheral arterial occlusive disease with an implication for anti-inflammatory effects

Although it is known that LDL-apheresis improves ischemic limb seen in patients with peripheral arterial occlusive disease (PAOD), anti-inflammatory effects are not well known. We studied whether or not serum or plasma levels of high sensitivity C-reactive protein (hsCRP), monocyte chemoatractant protein-1 (MCP-1), or fibrinogen could contribute to favorable effects for ischemic limbs after LDL-apheresis. Twenty-eight patients with PAOD (24 men, 4 women) were enrolled in our study. LDL-apheresis was performed 10 times (treated plasma of 3,000 ml) for 5 weeks. Serum levels of logarithmically transformed values of hsCRP significantly decreased from 3.666 +/- 0.126 to 3.482 +/- 0.139 ng/ml before and after a single session of LDL-apheresis (P < 0.001). Serum levels of MCP-1 decreased from 233 +/- 17.5 to 187 +/- 13.5 pg/ml before and after LDL-apheresis (P < 0.05). Likewise, plasma fibrinogen levels statistically decreased from 196 +/- 9.82 to 159 +/- 9.60 mg/dl (P < 0.001). Overall rates of improvement including foot chillness or numbness, and double folds increase in walking distance were 82.1% 3 months after a completion of LDL-apheresis, while gangrene was only improved 14.3%. Intermittent claudication improved in 53.6%. The favorable actions of LDL-apheresis might include anti-inflammatory effects. To avoid amputation, LDL-apheresis should be applied for patients with PAOD at an early stage of the disease process and may be applicable for patients with atherosclerotic cardiovascular disorders.

POOR NUTRITIONAL STATUS AND INFLAMMATION: Serum Albumin: Relationship to Inflammation and Nutrition

Hypoalbuminemia is the result of the combined effects of inflammation and inadequate protein and caloric intake in patients with chronic disease such as chronic renal failure. Inflammation and malnutrition both reduce albumin concentration by decreasing its rate of synthesis, while inflammation alone is associated with a greater fractional catabolic rate (FCR) and, when extreme, increased transfer of albumin out of the vascular compartment. A vicious cascade of events ensues in which inflammation induces anorexia and reduces the effective use of dietary protein and energy intake and augments catabolism of the key somatic protein, albumin. Hypoalbuminemia is a powerful predictor of mortality in patients with chronic renal failure, and the major cause of death in this population is due to cardiovascular events. Inflammation is associated with vascular disease and likely causes injury to the vascular endothelium, and hypoalbuminemia as two separate expressions of the inflammatory process. Albumin has a myriad of important physiologic effects that are essential for normal health. However, simply administering albumin to critically ill patients with hypoalbuminemia has not been shown to improve survival or reduce morbidity. Thus the inference from these clinical studies suggests that the cause of hypoalbuminemia, rather than low albumin levels specifically, is responsible for morbidity and mortality.

POOR NUTRITIONAL STATUS AND INFLAMMATION: Novel Approaches in an Integrated Therapy of Inflammatory-Associated Wasting in End-Stage Renal Disease

It is increasingly apparent that end-stage renal disease (ESRD) patients carry an inflammatory burden, which may play a pivotal role in the evolution of not only wasting, but also the massive increase in the relative risk of cardiovascular disease (CVD). Thus wasting is strongly associated with a persistent systemic inflammatory response, CVD, and impaired patient survival in end-stage renal disease (ESRD), as well as in other chronic diseases. Evidence suggests that a facilitative interaction between inflammatory cytokines and other factors such as poor appetite, comorbidity, acidosis, anemia, and hormonal derangements may cause wasting in this patient group. Clearly, isolated interventions in the form of nutritional energy and protein supplementation have seldom proven to be very effective in improving nutritional status and outcome in ESRD patients, presumably because of the need to attack other causative factors. Therefore, new treatment strategies must be evaluated. Strategies such as multiple appetite stimulants, various "anti-inflammatory diets," and new potentially useful anti-inflammatory pharmacologic agents may be tested alone, or in combination, to evaluate if these new therapeutic modalities can improve the outcome of ESRD patients. As the etiology of wasting in ESRD is multifactorial, we propose that its treatment must include not one, but a number of concomitant measures to provide an integrated therapy against this devastating complication.

POOR NUTRITIONAL STATUS AND INFLAMMATION: Ultrapure Dialysate

To prevent pyrogenic reactions during hemodialysis, it is recommended that bacteria and endotoxin in dialysate not exceed 100-200 colony forming units (CFU)/ml and 0.25-2 endotoxin units (EU)/ml, respectively. While these limits are adequate to prevent acute pyrogenic reactions, data are accumulating to suggest they may not prevent stimulation of chronic inflammation in hemodialysis patients. Fragments of endotoxin and other bacterial products capable of stimulating immune cells cross low-flux and high-flux membranes in vitro. In clinical studies, use of ultrapure dialysate (bacteria < 0.1 CFU/ml and endotoxin < 0.03 EU/ml) is associated with lower concentrations of inflammatory markers and acute phase reactants than are observed with dialysate meeting current quality recommendations. Moreover, observational studies suggest a link between clinical outcomes and dialysate purity. Treatment of patients with ultrapure dialysate is reported to improve nutritional status, increase responsiveness to erythropoietin, slow the decline in residual renal function, lessen cardiovascular morbidity, and decrease the incidence of beta(2)-microglobulin amyloidosis. To date, however, none of these studies has shown a cause-and-effect relationship between dialysate purity and outcome. Further, there are no data defining the concentration dependence of outcomes on dialysate purity and the relative importance of dialysate purity as a trigger of inflammation remains unclear. While the technology exists to routinely provide ultrapure dialysate, controlled clinical trials are still needed to answer the question of whether or not introducing ultrapure dialysate into routine clinical practice represents an efficient use of limited resources in terms of decreasing inflammation and improving outcomes in hemodialysis patients.

Impairment of small intestinal protein assimilation in patients with end-stage renal disease: extending the malnutrition-inflammation-atherosclerosis concept

BACKGROUND

Protein malnutrition is a common finding in renal disease. Recently, we showed that impaired protein assimilation (digestion and absorption) may contribute to protein malnutrition in nondiabetic patients with chronic renal failure.

OBJECTIVE

The aim of the present study was to evaluate whether these findings can be extended to the dialysis population. Moreover, relations with indexes of the malnutrition-inflammation-atherosclerosis (MIA) syndrome were investigated.

DESIGN

Protein assimilation was evaluated in 24 healthy control subjects and in 40 patients with end-stage renal disease (ESRD; 14 treated with peritoneal dialysis and 26 with hemodialysis) by means of a [13C]protein breath test, quantification of the generation rate of p-cresol, or both methods. Both approaches provide reliable information on the efficiency of protein assimilation. Breath test results were expressed as the maximum percentage recovery per hour of the administered dose of 13C (%max) and as the cumulative percentage recovery at the end of the test (%cum end). Several indexes of nutritional status, inflammation, and atherosclerosis were assessed.

RESULTS

Compared with the control subjects, ESRD patients had significantly lower breath-test derived indexes of protein assimilation [%max=3.75 +/- 0.30 compared with 4.90 +/- 0.25, P=0.006; %cum end=12.41 (5.74-23.22) compared with 16.87 (9.42-22.99), P=0.020] and a higher 24-h p-cresol generation rate corrected for dietary protein intake [3.89 (0.48-11.60) compared with 2.81 (0.21-11.20) mg p-cresol/g urea nitrogen; P=0.028]. The presence of impaired protein assimilation was associated with indexes of the MIA syndrome.

CONCLUSION

Our study provides evidence that protein assimilation is impaired in ESRD patients. Moreover, this disorder is associated with the severity of the MIA syndrome.

Dialysis Outcomes and Practice Patterns Study (DOPPS) data on medications in hemodialysis patients

BACKGROUND

Medications affect many measures of hemodialysis patients' well-being.

METHODS

The Dialysis Outcomes and Practice Patterns Study (DOPPS) has evaluated the use of hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins), analgesics, antidepressants, and multivitamins. Additionally, DOPPS has reported on the associations between vascular access outcomes and related medications.

RESULTS

Prescription of statins varied widely across countries, with the highest use in the United States. Patients prescribed statins had lower risk of cardiac and noncardiac causes of mortality than those who were not prescribed statins. DOPPS data also show that statins are underprescribed relative to recent Kidney Disease Outcomes Quality Initiative guidelines. No guidelines have been established for analgesic use, but high pain levels self-reported by hemodialysis patients suggest opportunities for improved pain management strategies. Guidelines for analgesic use in dialysis patients may help balance improved quality of life against potential side effects of analgesics. Medical and patient questionnaires show that depression in hemodialysis patients is common, frequently underdiagnosed, usually untreated, and associated with increased rates of mortality and hospitalization. Calcium channel blockers were associated with improved primary graft patency, aspirin with improved secondary graft patency, and angiotensin-converting enzyme inhibitors with improved secondary fistula patency. All 3 medications were associated with significantly decreased relative risk for access failure. There is large country variation in multivitamin use, with significantly higher use in the United States compared with Europe and Japan. Patients taking multivitamins had lower mortality risk than patients not taking multivitamins.

CONCLUSION

DOPPS findings on medications indicate that prospective trials are needed before guidelines can be developed for appropriate medication use in these different therapeutic categories.

Uremia accelerates both atherosclerosis and arterial calcification in apolipoprotein E knockout mice

Chronic renal failure (CRF) favors the development of atherosclerosis and excessive calcification of atheromatous lesions. CRF was induced in apolipoprotein E knockout (apoE(-/-)) mice to study (1) a possible acceleration of aortic atherosclerosis, (2) the degree and type of vascular calcification, and (3) factors involved in the calcification process. For creating CRF, 8-wk-old apolipoprotein E gene knockout (apoE(-/-)) mice underwent partial kidney ablation. Control animals underwent sham operation. Aortic atherosclerotic plaques and calcification were evaluated using quantitative morphologic image processing. At 6 wk after nephrectomy, CRF mice had significantly higher serum urea, cholesterol, and triglyceride concentrations than non-CRF controls. The serum levels of advanced oxidation protein products were elevated in the uremic group and were correlated with serum urea levels. Atherosclerotic lesions in thoracic aorta were significantly larger in uremic apoE(-/-) mice than in nonuremic controls. The relative proportion of calcified area to total surface area of both atherosclerotic lesions and lesion-free vascular tissue was increased in aortic root of uremic apoE(-/-) mice when compared with controls. The calcium deposits were made of hydroxyapatite and calcite crystals. In addition, plaques from uremic animals showed a significant increase in collagen content, whereas the degree of macrophage infiltration was comparable in both groups. There was no difference in mean arterial BP. These findings demonstrate that CRF aggravates atherosclerosis in apoE(-/-) mice. Moreover, CRF enhances arterial calcification at both atheromatous intimal sites and atheroma-free medial sites. We anticipate that this experimental model will be useful to test treatment strategies aimed at decreasing the accelerated atherosclerosis and arterial calcification in uremia.

Epidemiology, pathophysiology and therapeutic implications of lipoprotein(a) in kidney disease

Chronic kidney disease is associated with a tremendously increased risk for cardiovascular disease. Traditional risk factors for cardiovascular disease, however, show a diminished predictive power in these patients compared with the general population. This review provides an overview of lipoprotein(a), which is considered a nontraditional risk factor. The characteristic genetic and nongenetic changes of lipoprotein(a) in kidney disease are discussed and set into the context of risk prediction. In particular, genetically determined apolipoprotein(a) polymorphism is a powerful risk predictor for cardiovascular disease and total mortality in these patients. Finally, the limited interventional strategies available to lower lipoprotein(a) are considered.

Truncal fat mass as a contributor to inflammation in end-stage renal disease

BACKGROUND

An activated inflammatory response is a common feature of end-stage renal disease (ESRD) and predicts outcome. Adipose tissue is an endocrine organ that may contribute to an inflammatory burden by secreting adipocytokines such as interleukin 6 (IL-6).

OBJECTIVE

The objective was to relate plasma concentrations of IL-6 in ESRD patients to body composition, regional fat mass distribution, and blood lipid profiles.

DESIGN

One hundred ninety-seven ESRD patients (123 men; +/- SE age: 52 +/- 1 y) were evaluated shortly before dialysis started. Lean body mass and truncal and nontruncal fat mass were estimated by dual-energy X-ray absorptiometry. Nutritional status was evaluated on the basis of subjective global assessment and handgrip strength. Inflammatory biomarker and blood lipid concentrations were also evaluated.

RESULTS

Median IL-6 (8.5 compared with 4.5 pg/mL; P < 0.001) concentrations were significantly greater in malnourished than in well-nourished patients. Moreover, negative correlations were observed between IL-6 and serum creatinine (rho = -0.19, P < 0.01), handgrip strength (rho = -0.24, P < 0.001), and serum albumin (rho = -0.34, P < 0.001). A significantly higher truncal fat mass (12.8 +/- 0.7 compared with 10.5 +/- 0.4 kg; P < 0.005) was observed in ESRD patients with inflammation (C-reactive protein >/= 10 mg/L). Inverse correlations were observed between plasma IL-6 and HDL cholesterol (rho = -0.16, P < 0.05) and apolipoprotein A (rho = -0.23, P < 0.001).

CONCLUSIONS

Plausible relations exist between inflammatory biomarkers, such as IL-6 and high-sensitivity C-reactive protein, and regional fat distribution in ESRD patients. Moreover, the strong inverse relations between HDL cholesterol and apolipoprotein A and biomarkers of inflammation suggest that the chronic inflammatory response observed in ESRD patients is an important contributor to the atherogenic lipoprotein profile in uremia.

Uremic malnutrition is a predictor of death independent of inflammatory status

BACKGROUND

Several studies have pointed out the influence of nutritional parameters and/or indices of inflammation on morbidity and mortality. Often, these conditions coexist, and the relative importance of poor nutritional status and chronic inflammation in terms of predicting clinical outcomes in chronic hemodialysis (CHD) patients has not been clarified.

METHODS

We undertook a prospective cohort study analyzing time-dependent changes in several established nutritional and inflammatory markers, and their influence on mortality in 194 CHD patients (53% male, 36% white, 30% with diabetes mellitus, mean age 55.7 +/- 15.4 years) throughout a 57-month period. Serial measurements of serum concentrations of albumin, prealbumin, creatinine, transferrin, cholesterol, and C-reactive protein (CRP), as well as normalized protein catabolic rate, postdialysis weight, and phase angle and reactance by bioelectrical impedance analysis were performed every 3 months. Clinical outcomes were simultaneously assessed using indicators of mortality.

RESULTS

Serum albumin, serum prealbumin, serum creatinine, and phase angle were significant predictors of all-cause mortality, even after adjustment for serum CRP concentrations. Serum CRP concentrations were not significantly associated with mortality. Serum albumin concentrations and phase angle were also independent predictors of cardiovascular deaths in the multivariate model.

CONCLUSION

The nutritional status of CHD patients predicts mortality independent of concomitant presence or absence of inflammatory response. Prevention of, and timely intervention to treat uremic malnutrition by suitable means are necessary independent of the presence and/or therapy of inflammation in terms of improving clinical outcomes in CHD patients.

Parenteral iron compounds sensitize mice to injury-initiated TNF-alpha mRNA production and TNF-alpha release

Intravenous Fe is widely used to treat anemia in renal disease patients. However, concerns of potential Fe toxicity exist. To more fully define its spectrum, this study tested Fe's impact on systemic inflammation following either endotoxemia or the induction of direct tissue damage (glycerol-mediated rhabdomyolysis). The inflammatory response was gauged by tissue TNF-alpha message expression and plasma TNF-alpha levels. CD-1 mice received either intravenous Fe sucrose, -gluconate, or -dextran (FeS, FeG, or FeD, respectively; 2 mg), followed by either endotoxin (LPS) or glycerol injection 0-48 h later. Plasma TNF-alpha was assessed by ELISA 2-3 h after the LPS or glycerol challenge. TNF-alpha mRNA expression (RT-PCR) was measured in the kidney, heart, liver, lung, and spleen with Fe +/- LPS treatment. Finally, the relative impacts of intramuscular vs. intravenous Fe and of glutathione (GSH) on Fe/LPS- induced TNF-alpha generation were assessed. Each Fe preparation significantly enhanced LPS- or muscle injury-mediated TNF-alpha generation. This effect was observed for at least 48 h post-Fe injection, a time at which plasma iron levels were increased by levels insufficient to fully saturate transferrin. Fe did not independently increase plasma TNF-alpha or tissue mRNA. However, it potentiated postinjury-induced TNF-alpha mRNA increments and did so in an organ-specific fashion (kidney, heart, and lung; but not in liver or spleen). Intramuscular administration, but not GSH treatment, negated Fe's ability to synergize LPS-mediated TNF-alpha release. We conclude 1) intravenous Fe can enhance TNF-alpha generation during LPS- or glycerol-induced tissue damage; 2) increased TNF-alpha gene transcription in the kidney, heart, and lung may contribute to this result; and 3) intramuscular administration, but not GSH, might potentially mitigate some of Fe's systemic toxic effects.

Regulation of PTH1 receptor expression by uremic ultrafiltrate in UMR 106-01 osteoblast-like cells

BACKGROUND

Homologous down-regulation/desensitization of the parathyroid hormone receptor (PTH1R)/adenylate cyclase system has been demonstrated in uremia, and may contribute to parathyroid hormone (PTH) resistance; however, additional studies have shown that parathyroidectomy fails to normalize the down-regulation of the PTH1R. The present studies were designed to test directly, in vitro, the hypothesis that factors circulating in the uremic environment, other than PTH, decrease the response of osteoblastic cells to PTH.

METHODS

Studies were conducted in confluent cultures of UMR 106-01 osteoblast-like cells. Uremic ultrafiltrate (UUF) was obtained from patients on hemodialysis. Cells were exposed to media containing 50% uremic ultrafiltrate for periods of up to 72 hours. Control cultures were exposed to a buffered salt solution containing a comparable ionic composition to that of the UUF. PTH-stimulated cyclic adenosine monophosphate (cAMP) generation was determined by radioimmunoassay (RIA), PTH binding and PTH1R mRNA levels were determined by radioligand binding and Northern analysis, respectively.

RESULTS

PTH-stimulated cAMP generation from cultures treated with uremic ultrafiltrate for 48 hours was 1385.8 +/- 183.2 pmol/culture/5 minutes, whereas control cultures generated 2389.5 +/- 271 pmol cAMP/culture/5 minutes (P < 0.05). PTH binding was decreased by 30% in cultures incubated with UUF as compared to controls. The decrease in binding induced by UUF was accompanied by a decrease in PTH1R mRNA levels.

CONCLUSION

These findings demonstrate that factors present in UUF decrease PTH-stimulated cAMP generation by a mechanism that involves a decrease in the levels of PTH1R mRNA levels. Thus, the skeletal resistance to PTH in the setting of chronic kidney disease, may be explained, at least in part, by circulating factors other than PTH.

Increased prevalence of oxidant stress and inflammation in patients with moderate to severe chronic kidney disease

BACKGROUND

The prevalence of increased oxidative stress and acute-phase inflammation in patients with chronic kidney disease (CKD) has not been thoroughly investigated.

METHODS

Biomarkers of oxidative stress and acute-phase inflammation were measured in a cohort of 60 patients with stage 3-5 CKD compared to a healthy subject cohort. Levels of oxidative stress and inflammation were also compared to estimated glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) formula.

RESULTS

All biomarkers of oxidative stress (plasma protein carbonyl group content, plasma free F2-isoprostane content, plasma protein reduced thiol content) and all markers of inflammation [C-reactive protein (CRP), interleukin-6 (IL-6)] differed significantly between CKD patients and healthy subjects. There was no significant relationship between estimated GFR and any oxidative stress or inflammation biomarker. CRP levels were higher in patients with known coronary vascular disease (CVD) and in patients not taking angiotensin II inhibitors. Plasma IL-6 levels were significantly higher in patients with known coronary vascular disease and lower in patients taking statins. Biomarkers of oxidative stress were significantly higher in patients with diabetes and hypercholesterolemia.

CONCLUSION

There is evidence of increased oxidative stress and acute-phase inflammation in patients with stage 3-5 chronic kidney disease compared to healthy subjects that does not closely correlate with estimates of GFR. Among CKD patients, inflammatory biomarkers correlate with known CVD and inversely correlate with the use of angiotensin II inhibitors and statins. A further increase in oxidative stress was noted in diabetic and hypercholesterolemic patients. Inflammation and oxidative stress may contribute to cardiovascular risk in CKD patients.

The renal patient with coronary artery disease

The patient with chronic kidney disease and coronary artery disease (CAD) presents special challenges. This report reviews the scope of the challenge, the hostile internal milieu predisposing to CAD and cardiac events, management issues, unresolved dilemmas, and the need for randomized trials to allow for evidence-based treatment.

Adiponectin in renal disease: relationship to phenotype and genetic variation in the gene encoding adiponectin

BACKGROUND

The prevalence of cardiovascular disease (CVD) and inflammation is high in patients with end-stage renal disease (ESRD). Adiponectin is an adipocytokine that may have significant anti-inflammatory and anti-atherosclerotic effects. Low adiponectin levels have previously been found in patients with high risk for CVD.

METHODS

In a cohort of 204 (62% males) ESRD patients aged 52 +/- 1 years the following parameters were studied: presence of CVD, body composition, plasma adiponectin (N= 107), cholesterol, triglycerides, HDL-cholesterol, serum leptin, high-sensitivity C-reactive protein (hs-CRP), urinary albumin excretion (UAE), and single-nucleotide polymorphisms (SNPs) in the apM1 gene at positions -11391, -11377, 45, and 276. Thirty-six age- (52 +/- 2 years) and gender-matched (64% males) healthy subjects served as control subjects.

RESULTS

Markedly (P < 0.0001) elevated median plasma adiponectin levels were observed in ESRD patients (22.2 microg/mL), especially type 1 diabetic patients (36.8 microg/mL), compared to control subjects (12.2 microg/mL). Log plasma adiponectin correlated to visceral fat mass (R=-0.29; P < 0.01) and Log hs-CRP (R=-0.26; P < 0.01). In a stepwise (forward followed by backward) multiple regression model only type-1 diabetes (P < 0.001) and visceral fat mass (P < 0.05) were independently associated with plasma adiponectin levels. The adiponectin gene -11377 C/C genotype was associated with a lower prevalence of CVD (25 vs. 42%) compared to the G/C genotype.

CONCLUSION

The present cross-sectional study demonstrates that, whereas genetic variations seem to have a minor impact on circulating adiponectin levels, lower visceral fat mass and type 1 diabetes mellitus are associated with elevated plasma adiponectin levels in ESRD patients. Furthermore, low levels of adiponectin are associated with inflammation in ESRD.

Impaired Endothelial Release of Tissue-Type Plasminogen Activator in Patients With Chronic Kidney Disease and Hypertension

We have shown that the capacity for local release of tissue-type plasminogen activator (tPA) from the vascular endothelium is impaired in patients with primary hypertension. Because this response is an important protective mechanism against intravascular clotting, we investigated whether this system is also defective in patients with advanced chronic kidney disease and hypertension. Nine nondiabetic nonsmoking men with chronic kidney disease (glomerular filtration rate 11 to 28 mL/min x 1.73 m2; aged 33 to 75 years) were compared with age-matched healthy controls. Intraarterial infusions of desmopressin, methacholine, and sodium nitroprusside were given locally in the brachial artery. Forearm blood flow was measured by venous occlusion plethysmography and blood collected repeatedly during the desmopressin infusion for determination of stimulated net and total cumulated release of tPA. The maximal release rate of active tPA (P<0.05) and the capacity for acute tPA release were markedly impaired in the renal patients as compared with healthy subjects (ANOVA, P=0.013). Accordingly, the accumulated release of tPA was 1905 (SEM 366) and 3387 (718) ng/L tissue, respectively (P<0.05). However, there were no significant differences in vasodilator responses between the groups. Thus, patients with advanced chronic kidney disease and hypertension have a markedly impaired capacity for acute release of tissue plasminogen activator, despite preserved endothelium-dependent vasodilation. This defect may contribute to a defective local defense against arterial thrombosis.

Albumina sérica como marcador nutricional de pacientes em hemodiálise

A prevalência de desnutrição protéico-energético em pacientes com insuficiência renal crônica submetidos à terapia de hemodiálise é elevada. Dentre os diversos parâmetros disponíveis para a avaliação do estado nutricional, a albumina tem sido o mais comumente utilizado para este fim visto a sua estreita associação com a morbidade e mortalidade nesta população. No entanto, vários fatores como idade, comorbidades, hipervolemia e perdas corpóreas podem influenciar as concentrações séricas de albumina. Além disso, na vigência de inflamação, condição comumente presente neste grupo de pacientes, o metabolismo da albumina pode encontrar-se alterado, influenciando os seus níveis plasmáticos. Sendo assim, esta comunicação tem como objetivo abordar os aspectos gerais da albumina e discutir a sua utilização na avaliação do estado nutricional de pacientes com insuficiência renal crônica submetidos à hemodiálise.

Serum malondialdehyde and coronary artery disease in hemodialysis patients

BACKGROUND/AIMS

It has been suggested that enhanced oxidative stress participates in the acceleration of coronary artery disease (CAD) in patients with end-stage renal disease (ESRD). The aim of this study was to investigate the relationship between the level of malondialdehyde (MDA), which is a marker of lipid peroxidation, and the severity of CAD in ESRD patients.

METHODS

We conducted a study of 39 hemodialysis patients (median age 58 years; 27 males and 12 females; diabetics 44%). In these patients, the predialysis serum concentrations of MDA and C-reactive protein (CRP) were measured. We performed multirow spiral computed tomography to derive coronary artery calcification (CAC) scores, as a marker of CAD severity.

RESULTS

Eleven of the 39 patients had minimal CAC (28%, CAC score <10), 10 patients had mild to moderate CAC (26%, 10-400), and 18 patients had severe CAC (46%, >400). The MDA levels increased (p < 0.05) with increasing CAC category and were correlated (r = 0.35, p < 0.05) with the CAC scores. The levels of MDA also correlated with the serum concentrations of CRP and albumin (r = 0.34, p < 0.05 and r = -0.32, p < 0.05, respectively). Patients in the highest tertile of MDA compared with the other patients were over four times as likely to have severe CAC, and the highest tertile of MDA was an independent predictor of severe CAC, along with a previous cardiovascular event.

CONCLUSION

An increased level of MDA, which was associated with inflammatory markers, was a predictive factor for severe CAC in ESRD patients.

Carotid atherosclerosis in chronic renal failure-the central role of increased plaque burden

Studies on carotid artery atherosclerosis have been performed in order to understand the high risk for cardiovascular disease in chronic renal failure (CRF). The purpose of this study was to evaluate the extent and nature of carotid artery atherosclerosis in patients with CRF. Of the 135 patients with CRF (52 +/- 11 years), 58 had moderate to severe predialysis CRF (PR), 36 were on dialysis treatment (DI), and 41 were renal transplant recipients (TR). In addition, 58 control subjects (CO) were examined. Common carotid artery intima-media thickness (IMT), plaque prevalence, plaque score, and stiffness index beta were determined. Furthermore, plaque calcification and internal carotid artery stenoses were classified. Plaque prevalence (PR 64%, DI 61%, TR 51%, CO 28%; P < 0.001) and plaque score (PR 3.3 +/- 4.3, DI 3.0 +/- 3.4, TR 2.5 +/- 3.2, CO 0.8 +/- 1.7 mm; P < 0.001) were significantly greater in the CRF patient groups compared to the controls, whereas no difference in IMT was noted between the study groups. The prevalences of plaque calcification and internal carotid artery stenoses were higher among the CRF patient groups. In addition, the stiffness index beta was higher in the CRF patient groups. The present study shows that the characteristic alterations of the carotid arteries in CRF include increased plaque burden, calcification and increased arterial stiffness.

The body mass index paradox and an obesity, inflammation, and atherosclerosis syndrome in chronic kidney disease

The association of high body mass index (BMI) with better survival in chronic kidney disease (CKD) is considered a "risk factor paradox" or "reverse epidemiology." Since malnutrition is a powerful predictor of death and cardiovascular disease is its leading cause, it has been suggested that malnutrition and atherosclerosis must be associated. Thus the current paradigm is that malnutrition is a risk factor for atherosclerosis and obesity is protective in CKD patients. We recently showed that high-BMI patients with inferred high body fat have an increased prevalence of atherosclerosis and subsequent cardiovascular and all-cause mortality. Prior cross-sectional studies also showed that high BMI in CKD is associated with higher C-reactive protein (CRP) levels and increased coronary calcification on electron beam computed tomography (CT) scan. These apparently conflicting data on better survival but increased inflammation and atherosclerosis in high-BMI CKD patients could be explained as follows. It is hypothesized that nutrition exerts a much stronger influence on survival than atherosclerosis in CKD. Malnutrition strongly augments the hazard of death from coexistent diseases, while better nutrition has the opposite effect. Thus the risk of death is highest in malnourished patients (low muscle and low fat mass) and lowest in well-nourished patients (high BMI, high muscle mass). Obesity (high BMI, high fat mass) is associated with inflammation and atherosclerosis. The risk of death from obesity and atherosclerosis is increased, but not so much as occurs with malnutrition. Therefore high body fat patients have intermediate survival. Thus it is postulated that an association of obesity, inflammation, and atherosclerosis (OIA syndrome) might exist in CKD.

Chlamydial infection and progression of carotid atherosclerosis in patients on regular haemodialysis

BACKGROUND

Recent findings have suggested a possible contribution of chlamydial infection to the pathogenesis of atherosclerosis in the general population. However, the role that chlamydial antibody status plays in atherosclerosis generation in haemodialysis (HD) patients remains uncertain.

METHODS

We measured carotid artery intima medial thickness (IMT) over 4 years in 100 HD subjects (age: 58+/-10 years; time on HD: 13+/-7 years; male/female: 67/33) and examined potential associations between Chlamydia pneumoniae (Cp) antibody seropositivity and changes in carotid artery IMT.

RESULTS

During 4 years, carotid artery IMT increased significantly from 0.62+/-0.13 to 0.73+/-0.12 mm (P< 0.01). IMT progression was significantly and positively correlated with age (r = 0.37, P<0.01), log-transformed C-reactive protein (CRP; r = 0.33, P<0.01) and log-transformed interleukin-6 (IL-6; r = 0.22, P<0.04), but inversely correlated with blood creatinine (r = -0.36, P<0.01) and albumin (r = -0.24, P<0.02). IMT increases were more prominent in patients positive for IgA antibodies (0.039+/- 0.022 mm/year, n = 52) compared with those without IgA antibodies (0.025+/-0.032 mm/year, n = 48) (P<0.01). IgA seropositivity did not accelerate IMT progression in patients with increased CRP (>0.11 mg/dl, n = 53), but significantly increased IMT to a greater extent in IgA-positive subjects than in IgA-negative subjects having lower CRP (</=0.11 mg/dl, n = 47) (0.017+/-0.024 vs 0.034+/- 0.021 mm/year; P = 0.01). Multivariate regression analysis revealed that serum creatinine, log-transformed CRP and IgA Cp seropositivity were independent risk factors for IMT progression (P<0.01). In contrast, IgG Cp antibody did not affect IMT progression or carotid plaque formation.

CONCLUSIONS

IMT progression is associated with inflammation and malnutrition. In addition, persistent chlamydial infection may be associated with IMT progression, but only in HD patients having low blood CRP.

Measurement of circulating troponin Ic enhances the prognostic value of C-reactive protein in haemodialysis patients

BACKGROUND

Cardiac Troponin I (cTnI) levels are considered an important diagnostic tool in acute coronary events. They could be of predictive value in haemodialysis (HD) patients. However, the relationship between cTnI and the HD-induced inflammatory state remains unclear. The aim of this study was to explore the prognostic relevance to all-cause and cardiovascular mortalities in HD patients of cTnI, in combination with highly sensitive C-reactive protein (hs-CRP) levels.

METHODS

We measured cTnI and hs-CRP at baseline (March 10 to November 16, 2001) in 191 HD patients without clinical signs of acute coronary artery disease [median age 66.7 years (range 22.3-93.5), 94 females, 97 males]. We used a cTnI concentration with a total imprecision of 10% (0.03 microg/l), determined in the laboratory, as the analytical threshold value. Patients were followed for mortality until 1 January, 2003 (median follow-up 418 days). The adjusted relative risks (RRs) of death and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models.

RESULTS

A significant proportion (25.1%) of patients had elevated CTnl, > or =0.03 microg/l; 40.3% of patients had CRP concentrations > or =10 mg/l. During follow-up, 29 patients died, 44.8% due to cardiac causes. Elevated cTnI or CRP levels were associated with increased mortality [RR adjusted for age, sex and duration of dialysis 4.2 (1.9-9.0) for cTnI > or =0.03 microg/l and 3.6 (1.6-8.1) for CRP > or =10 mg/l], cTnI being particularly predictive of cardiovascular death. Moreover, the combination of elevated hs-CRP (> or =10 mg/l) and circulating cTnI (> or =0.03 microg/l) dramatically impaired the HD survival rate [adjusted RR for all-cause mortality 16.9 (4.5-63.8)].

CONCLUSION

Circulating cTnI was associated with poor prognosis, especially when combined with elevated CRP, strongly supporting the adoption of regular cTnI testing in HD patients.

Monocyte adhesion molecule expression in interstitial inflammation in patients with renal failure

BACKGROUND

Patients with renal failure have an increased susceptibility to infections. We therefore studied the recruitment of monocytes and their expression of adhesion molecules CD11b and CD62L at the site of interstitial inflammation in patients with renal failure. Furthermore, we studied if the capacity of monocytes to up-regulate CD11b in interstitial inflammation was determined by the interstitial concentration of chemotactic factors.

METHODS

Three intensities of interstitial inflammation (0, intermediate and intense) were established in skin blister chambers. Leukocyte count, CD11b/CD62L expression, monocyte chemotactic protein-1 (MCP-1) and blister activity in terms of CD11b mobilization were determined.

RESULTS

The CD62L expression on monocytes was lower in the peripheral circulation in patients with renal failure compared with healthy subjects (P<0.005 and P<0.001). At the site of interstitial inflammation patients had a higher expression of CD62L (intermediate, P<0.05; intense, P<0.005). Furthermore, monocytes from patients had an impaired capacity to mobilize CD11b both in the peripheral circulation (P<0.005) and at the intermediate and intense sites of interstitial inflammation (P<0.005 and P<0.001, respectively) compared with cells collected from healthy subjects. We incubated monocytes in blister exudates, in order to explore whether this phenomenon is caused by cellular factors and/or to the interstitial concentration of chemotactic mediators. The expression of CD11b on monocytes from healthy blood donors incubated in blister exudates from either patients or healthy subjects in vitro was similar. The interstitial concentration of MCP-1 at the site of intermediate inflammation was significantly lower in patients with renal failure compared with the corresponding blister exudate collected from healthy subjects (P<0.05), but no differences were observed at the site of intense inflammation. Furthermore, neutralizing the action of MCP-1 in blister exudates with monoclonal antibodies did not have any impact on monocyte CD11b expression following incubation in blister exudates.

CONCLUSION

These studies indicate that the impaired capacity of monocytes to mobilize CD11b at the site of inflammation in patients with renal failure is more dependent on constitutive cellular factors than the concentration of CD11b mobilizing factors in the interstitium.

Reduced gene expression of adiponectin in fat tissue from patients with end-stage renal disease

BACKGROUND

Cardiovascular disease (CVD) is the main cause of death in end-stage renal disease (ESRD) patients. It has been suggested that inflammation plays a key role in the development of both atherosclerosis and malnutrition (MIA), a combination of complications associated with poor outcome. Although plasma levels of adiponectin, a recently discovered anti-inflammatory and antiatherogenic adipocytokine, are markedly elevated in ESRD, gene expression of adiponectin (ApM1) has not been analyzed in ESRD patients.

METHODS

We analyzed the ApM1 gene expression in adipose tissue from 18 ESRD patients of whom 9 (7 males, 60 +/- 8 years, BMI 24 +/- 6 kg/m(2)) had a high prevalence of MIA complications, and 9 age- (55 +/- 9 years), gender- (7 males) and BMI- (24 +/- 2 kg/m(2)) matched ESRD patients had few MIA complications. The results were compared with age- (59 +/- 11 years), gender- (7 males), and BMI- (24 +/- 6 kg/m(2)) matched healthy control patients. Information on CVD was obtained at the recruitment based on a detailed medical history. Malnutrition was defined as a subjective global assessment (SGA) score >1. Inflammation was defined as CRP >/=10 mg/L. Gene expression analysis was performed using the in situ hybridization technique.

RESULTS

Gene expression of ApM1 was lower in ESRD patients compared with healthy control patients (P= 0.001). On the other hand, when comparing the gene expression between ESRD patients with and without MIA complications, respectively, no difference in the ApM1 gene expression was detected.

CONCLUSION

Adiponectin gene expression is significantly down-regulated in ESRD patients compared with healthy control patients. We propose that the decrease in expression may be the result of a negative feedback regulation, as a result of elevated levels of circulating adiponectin caused by renal failure.

Potential cardiovascular risk factors in chronic kidney disease: AGEs, total homocysteine and metabolites, and the C-reactive protein

BACKGROUND

Total homocysteine (tHcy) and advanced glycation end-products (AGEs) are implicated in the pathogenesis of vascular damage. This study aimed to investigate whether elevated serum levels of the AGEs pentosidine, N(epsilon)-carboxymethyllysine (CML) and imidazolone; tHcy, cystathionine, methylmalonic acid (MMA), and 2-methylcitric acid (2-MCA), as well as C-reactive protein (CRP), are related to a higher risk for cardiovascular events.

METHODS

A total of 232 patients with chronic kidney diseases (mean age 57.6 +/- 13.1 years, 82 female and 150 male); 99 with chronic renal failure (CRF), 84 maintenance hemodialysis patients and 49 renal transplant recipients were followed for 2 years. The relationship between the parameters of interest, conventional risk factors and elevated levels of CRP with cardiovascular events was tested in all subjects by the Cox proportional hazards model.

RESULTS

Mean serum levels of AGEs, tHcy, and of the metabolites were found to be significantly increased in all three groups compared to the healthy subjects (P < 0.01, respectively). Fifty-three cardiovascular events occurred during follow-up; a total of 40 patients died. Final multivariate analysis showed diabetes (RR 2.06, 95% CI 1.17-3.60, P= 0.013), end-stage renal disease (ESRD) (RR 4.88, 95% CI 2.40-9.89, P < 0.001) and elevated CRP levels (RR 2.00, 95% CI 1.11-3.60, P= 0.021) as independent risk factors for cardiovascular events.

CONCLUSION

Data from a group consisting of patients with CRF, patients undergoing maintenance hemodialysis treatment, and renal transplant recipients provide evidence that conventional risk factors such as the presence of diabetes, ESRD, as well as elevated levels of the considered risk factor CRP, seem to play a more important role for cardiovascular outcome in patients with chronic kidney disease than elevated levels of AGEs, tHcy, and related metabolites. The evidence suggests that routine CRP measurement can be recommended in cases of chronic renal insufficiency.

Asymptomatic cerebral lacunae in patients with chronic kidney disease

BACKGROUND

It remains unknown whether the prevalence of silent lacunar infarcts increases as renal function declines or what factors known as atherosclerotic risk factors are related to the development of lacunar infarcts.

METHODS

Fifty-one patients with chronic kidney disease without diabetes mellitus and 80 patients with essential hypertension with normal renal function were included in the study. The existence of lacunar infarcts was evaluated on brain magnetic resonance imaging scans. We evaluated the severity of carotid atherosclerosis by means of intima-media thickness of 1.0 mm or greater height in bilateral carotid arteries and by affecting factors, including plasma homocysteine levels.

RESULTS

Lacunae prevalence was 25% in patients with a creatinine clearance (Ccr) greater than 40 mL/min/1.73 m2, 85% in patients with a Ccr less than 40 mL/min/1.73 m2, and 29% in patients with essential hypertension with normal renal function. Patients with lacunae had significantly lower hematocrits associated with increased fibrinogen and lipoprotein(a) levels compared with those without lacunae. Plasma total homocysteine and insulin levels at 2 hours after a 75-g glucose tolerance test correlated significantly with lacunae. Ischemic heart changes shown by electrocardiogram and thickened carotid intima-media thickness were significantly more frequent in patients with lacunae. However, logistic regression analysis showed that the most strongly contributing factor for lacunar infarcts was decline in Ccr (confidence interval, 0.933 to 0.995; P < 0.05).

CONCLUSION

Decreased renal function, even without diabetes mellitus, is a risk factor for silent lacunar infarcts.

Body size and outcomes on peritoneal dialysis in the United States

BACKGROUND

Being overweight is often cited as a relative contraindication to peritoneal dialysis. Our primary objective was to determine whether actual mortality rates support this opinion.

METHODS

Retrospective cohort study of United States Medicare patients initiating dialysis between 1995 and 2000 (N = 418,021; 11% peritoneal dialysis).

RESULTS

Seven percent were underweight [body mass index (BMI) < 18.5 kg/m2], 27% were overweight (BMI 25.0 to 29.9 kg/m2), and 23% were obese (BMI> 29.9 kg/m2) at dialysis initiation. Compared to those with normal BMI, the adjusted odds of initiating peritoneal dialysis were 0.70 (P < 0.05) in underweight, 1.12 (P < 0.05) in overweight, and 0.87 (P < 0.05) in obese subjects. Among peritoneal dialysis patients, adjusted mortality hazard ratios in the first, second, and third year were 1.45 (P < 0.05), 1.28 (P < 0.05), and 1.17 for the underweight, respectively; 0.84 (P < 0.05), 0.89 (P < 0.05), and 0.98 for the overweight, respectively; and 0.89 (P < 0.05), 0.99, and 1.00 for the obese, respectively. Apart from higher third-year mortality in the obese, associations were similar after censoring at a switch to hemodialysis. For transplantation, the corresponding results were 0.76 (P < 0.05), 0.90 (P < 0.05), and 0.88 for the underweight, respectively; 0.95, 1.06, and 0.93 for the overweight, respectively; and 0.62 (P < 0.05), 0.68, and 0.71 for the obese, respectively. For switching to hemodialysis, hazards ratios were 0.92, 0.97, and 0.80 for the underweight, respectively; 1.07, 1.11 (P < 0.05), and 1.03 for the overweight, respectively; and 1.28 (P < 0.05), 1.29 (P < 0.05), and 1.36 (P < 0.05) for the obese, respectively.

CONCLUSION

Although less likely to initiate peritoneal dialysis, overweight and obese peritoneal dialysis patients have longer survival than those with lower BMI, not adequately explained by lower transplantation and technique survival rates.

Association between serum ferritin and measures of inflammation, nutrition and iron in haemodialysis patients

BACKGROUND

Serum ferritin is a frequently used marker of iron status in dialysis patients. Iron administration is to be withheld for ferritin values >800 ng/ml according to K/DOQI guidelines. We hypothesized that such non-iron-related factors as elements of the malnutrition-inflammation complex syndrome (MICS) may increase serum ferritin concentration independently of iron status.

METHODS

We studied 82 prevalent maintenance haemodialysis (MHD) patients (including 43 men), aged 55.7 +/- 15.3 years. The inflammatory and nutritional status was evaluated by serum C-reactive protein (CRP), Subjective Global Assessment (SGA) and its newer, fully quantitative versions, i.e. Dialysis Malnutrition Score (DMS) and Malnutrition-Inflammation Score (MIS).

RESULTS

All but six patients had been on maintenance doses of intravenous iron dextran (between 100 and 200 mg/month) during the 10 weeks prior to the measurements. Serum ferritin levels were increased across SGA categories: (ANOVA P-value 0.03). Both unadjusted and multivariate adjusted correlation coefficients (r) for serum ferritin and CRP vs pertinent values were statistically significant for DMS and MIS and some other measures of nutritional status and iron indices. After deleting 10 MHD patients with either iron deficiency (ferritin <200 ng/ml) or iron overload (ferritin >2000 ng/ml), in the remaining 72 MHD patients both bivariate and multivariate correlations were much stronger and statistically significant (r = -0.33 and -0.29, respectively, P < 0.01). A multivariate model showed simultaneous, significant correlations between serum ferritin and both markers of inflammation and iron status independent of each other. After dividing the 72 MHD patients into two groups of serum ferritin based on a K/DOQI recommended serum ferritin cut-off of 800 ng/ml, the MIS and logarithm of serum CRP were significantly higher in the higher ferritin group.

CONCLUSIONS

Serum ferritin values in the range of 200-2000 ng/ml may be increased due to non-iron-related factors including elements of MICS.