Immune Profile and Body Composition of Independent Oldest Old: The Longevous Project

INTRODUCTION

Immunosenescence is associated with changes in lymphocyte function, thymus atrophy, and a chronic inflammatory process referred to as "inflammaging," which may in part be linked to eating disorders.

OBJECTIVE

The aim of the study was to determine the prevalence rate of immunological alterations, including immune risk profile (IRP), and their association with body composition in the oldest old individuals.

METHODS

A cross-sectional study of 201 older adults aged 80 years and over, able to walk unaided, with no cognitive or immunological impairment, and with no serious diseases was conducted. Blood samples were collected between 2012 and 2014 during the morning period, and the following tests were conducted: urea, creatinine, hemogram, fasting glucose, glycated hemoglobin, transferrin, albumin, 25-OH vitamin D, and high-sensitivity CRP. Plasma cytokines were measured and mononuclear cell counts were performed by flow cytometry. Anthropometric measurements and densitometry using dual-energy X-ray absorptiometry (DXA) were performed to assess body composition.

RESULTS

Mean age was 84.4 ± 3.7 years, and the numbers of T cells were CD4, 784.0 cell/µL; CD8, 371.0 cell/µL; and CD4/CD8, 2.4. The rate of CD4/CD8 <1 (IRP) was 9.4%, CD4/CD8 1-5 was 85.6%, while CD4/CD8 >5 was only 5.5%. CRP, tumor necrosis factor, IL1, IL4, IL6, and IL10 variables showed a high coefficient of variation but low mean values of 1.1 ± 3.1 mg/L for CRP (reference range <3 mg/L) and 3.9 ± 5.0 pg/mL for IL6 (reference range <7.0 pg/mL). The same pattern was found for all other inflammatory variables assessed, characterizing a population whose values indicated low level of inflammation, considering age. Lean mass, as measured by DXA, was higher in men than in women, while the inverse was found for fat % (p < 0.001). A positive association between CRP values and DXA fat % (p value: 0.007, r: 0.49) and a negative association between CRP values and DXA lean mass (p value: 0.046, r:-0.37) was observed.

CONCLUSION

In the independent oldest old, IRP rate proved low and high-sensitivity CRP was shown to be associated with body composition.

Increased Serum IL 6 Associated With Mortality and Cognitive Impairment in Elderly Brazilians

Immunological and inflammatory changes are gaining importance in aging as they are associated with functional limitations and mortality. Chronic inflammation associated with aging (Inflammaging) is a systemic and subclinical condition, characterized by changes in the levels of interleukins such as IL1, IL4, IL6, IL8, IL10 and TNF alpha, associated with genetic, physiological and environmental factors, whose importance is to be directly associated with morbidity and mortality in the elderly. Objective: To evaluate, through a longitudinal study, the relationship between chronic inflammation associated with aging and possible outcomes, such as cognitive changes and mortality in independent oldest old adults. Methods: were evaluated 201 elderly, aged 80 years or older, community residents, with preserved cognition, without acute diseases and with controlled chronic diseases. In a 02 years of interval, laboratory collections of inflammatory markers (IL 1, IL 4, IL6, IL10, TNF alpha and CRP) were performed and outcomes such as cognitive impairment and deaths were evaluated. Results: There was a correlation between increased serum IL6 and cognitive impairment, in the group of women (p-value = 0.008) and in the group All (p-value = 0.022). In the group of men, there was a significant difference between the increase in IL6 values ​​(p-value = 0.028) and CRP (p-value = 0.016) in relation to deaths. Conclusion: The results of this longitudinal study showed and confirmed the positive association between changes in inflammatory markers such as IL6 and outcomes such as cognitive impairment and mortality also in elderly Brazilians.

High Serum Levels of Soluble Fas (sFas) in Ckd Patients: Effects of Renal Clearance, Reabsorption and Synthesis

Purpose

Increased serum concentrations of soluble Fas (sFas) have been reported in patients with chronic kidney disease (CKD). However, little is known about the renal clearance of sFas, whether sFas is reabsorbed in the renal tubules, or the behavior of sFas synthesis in CKD.

Materials and Methods

We studied 69 patients with CKD (60±15 years old, creatinine clearance 37+19 ml/min/1.73 m2) and 14 healthy subjects (61±17 years, creatinine clearance 79±24 ml/min/1.73 m2). ELISA was used to measure the levels of sFas (pg/mL) and retinol binding protein (RBP - mg/L). RT-PCR was used to quantify sFasmRNA of leukocytes.

Results

Serum sFas levels were significantly higher in patients with CKD (2781±1214 vs. 2196±773, p=0.02). The concentrations of sFas in 24-hour urine samples (23±27 vs. 40±17, p=0.006) and sFas Clearance (0.019±0.022 vs. 0.036±0.020, p=0.01) were significantly lower in patients with CKD. sFas clearance correlated with creatinine clearance (r=0.25, p=0.02). Urine concentrations of RBP correlated with sFas concentrations in the urine (r=0.80, p<0.001). sFasmRNA were higher in patients with CKD (3.9±1.8 vs. 2.5±0.9, p<0.001).

Conclusions

In CKD patients, the decrease in renal function is followed by a decrease in sFas clearance and an increase in serum sFas. In patients with proximal tubule dysfunction (high urinary RBP concentrations), urinary sFas is also increased, suggesting that sFas is reabsorbed by the proximal tubule. It is possible that an increase in sFas synthesis also contributes to the increase of serum sFas concentrations in uremia.

Tumour necrosis factor-α plus interleukin-10 low producer phenotype predicts acute kidney injury and death in intensive care unit patients

Genetic polymorphism studies of cytokines may provide an insight into the understanding of acute kidney injury (AKI) and death in intensive care unit (ICU) patients. The aim of this study was to investigate whether the genetic polymorphisms of -308 G < A tumour necrosis factor (TNF)-α, -174 G > C interleukin (IL)-6 and -1082 G > A IL-10 may predispose ICU patients to the development of AKI and/or death. In a prospective nested case-control study, 303 ICU patients and 244 healthy individuals were evaluated. The study group included ICU patients who developed AKI (n = 139) and 164 ICU patients without AKI. The GG genotype of TNF-α (low producer phenotype) was significantly lower in the with AKI than without AKI groups and healthy individuals (55 versus 62 versus 73%, respectively; P = 0·01). When genotypes were stratified into four categories of TNF-α/IL-10 combinations, it was observed that low TNF-α plus low IL-10 producer phenotypes were more prevalent in patients with AKI, renal replacement therapy and death (P < 0·05). In logistic regression analysis, low TNF-α producer plus low IL-10 producer phenotypes remained as independent risk factors for AKI and/or death [odds ratio (OR) = 2·37, 95% confidence interval (CI): 1·16-4·84; P = 0·02] and for renal replacement therapy (RRT) and/or death (OR = 3·82, 95% CI: 1·19-12·23; P = 0·02). In this study, the combination of low TNF-α plus low IL-10 producer phenotypes was an independent risk factor to AKI and/or death and RRT and/or death in critically ill patients. Our results should be validated in a larger prospective study with long-term follow-up to emphasize the combination of these genotypes as potential risk factors to AKI in critically ill patients.

Postprandial interleukin-6 response in elderly with abdominal obesity and metabolic syndrome

OBJECTIVE

The aim of this study is to evaluate the contribution of central obesity to inflammatory responses in the postprandial state in elderly patients with and without metabolic syndrome (MetS).

MATERIAL/METHODS

We evaluated 80 elderly individuals who were distributed into three groups: MetS, abdominal obesity (AbObes) and Control, according to ATPIII criteria. Interleukin-6 (IL-6) serum concentration was measured at 0, 2, 4 and 6 hours after the ingestion of a physiological meal without an overload of fat.

RESULTS

Serum IL-6 increased 6 hours after the meal in all of the groups (P<0.001). Comparing the groups, there was no difference in the area under the curve (AUC) of IL-6 in the postprandial state. There was a correlation between the 6-hour changes in the concentrations of IL-6 and the homeostasis model assessment of insulin resistance (HOMA-IR) (r = 0.25, P<0.05).

CONCLUSION

In this study, differences in abdominal circumference (AC) have not determined a different behavior of IL-6 in the postprandial state, despite the correlation between AC and IL-6. However, we found that, in the elderly, there is a rise in serum IL-6 at 6 hours.

Clinical implications of initial renal function after deceased donor transplant

The aim of this study was to investigate whether slow graft function (SGF) after transplantation of deceased-donor kidneys affected the prevalence of anemia or the glomerular filtration rate (GFR). We retrospectively evaluated the records of 534 kidney transplant patients who were classified based on their initial renal function, namely, immediate graft function (IGF), slow graft function (SGF), or delayed graft function (DGF). Among the 534 kidney transplant patients studied, the occurrences of each condition were IGF 104, SGF 133, and DGF 297. Six months after transplantation, a greater percentage of DGF patients were anemic compared with the others (P = .028). However, at 12 months after transplantation, SGF patients showed more anemia than the IGF group. DGF and SGF patients displayed similar GFR values at 18 and 24 months after transplantation. However, IGF patients displayed higher GFRs, even when subjects who experienced acute rejection episodes were censored (P = .004). The incidence of acute rejection episodes was similar among SGF and DGF patients. Patients displaying SGF after deceased-donor transplantation showed a greater tendency to be anemic than those displaying IGF. This study also suggested that SGF patients were at risk for acute rejection episodes and/or significantly reduced kidney function as measured by GFR.

Infectious complications after deceased kidney donor transplantation

BACKGROUND

Despite improvements in immunosuppressive therapy, infections remain a complication of renal transplantation that is associated with increased morbidity and graft rejection. The aim of this study was to evaluate the relationship between initial renal function after deceased donor transplantation and viral infections.

METHODS

We included patients 18 years and older who received a deceased donor transplantation between January 1995 and December 2004. They were divided into 2 groups: cases from 1994 to 1999, versus from 2000 to 2004. Initial renal function was classified as immediate (IGF), slow (SGF), or delayed (DGF). Infections were classified according to Centers for Disease Control and prevention standards.

RESULTS

Among 534 patients, SGF and DGF patients who underwent immunosuppression between 2000 and 2004 show a higher infection rate than IGF patients (P = .005). SGF patients showed a higher incidence of tissue-invasive cytomegalovirus disease (P < .001). Second episodes of viral infections were more common among all patients in this period. However, DGF patients were more susceptible to second episodes of viral infection. In the first group, OKT3 use (P = .013) and donor age (P = .012) were the major risk factors associated with viral infections whereas in the second group, thymoglobulin use (P = .002), acute rejection episode (P = .003), and anemia (P = .044) were the risk factors for viral infection.

CONCLUSION

Initial renal function after deceased donor transplantation was correlated with viral infection. DGF patients had a higher risk for second infection episodes. SGF patients had a higher risk for tissue-invasive cytomegalovirus infection.

Lack of Impact of Hepatitis C Virus Coinfection in End-Stage Renal Disease Patients With Hepatitis B Virus Infection

INTRODUCTION

Hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfection results in more severe forms of liver disease in nonuremic patients; however, the impact of HCV coinfection is not clearly known in end-stage renal disease (ESRD) patients with HBV infection. We sought to determine the impact of HCV coinfection in HBV-infected ESRD patients.

PATIENTS AND METHODS

The HBsAg-positive ESRD patients evaluated between March 1999 and May 2003 were divided into two groups: group B, HBV infection alone, and group BC, HBV-HCV coinfection (anti-HCV-positive). Both groups were compared regarding epidemiological, laboratory, and histological findings. A liver biopsy was obtained in cases with evidence of viral replication and/or elevated alanine aminotransferase.

RESULTS

One hundred patients (73% men) with mean age of 42 +/- 11 years (55 patients in group B and 45 in group BC) were studied. Comparison between groups showed a difference in time on hemodialysis and duration of infection, which were higher in group BC (P < .001 and P = .001, respectively) and in history of blood transfusion, which was also more frequent in group BC (P = .04). Liver biopsies, obtained from 15 patients in group B and 28 patients in group BC, showed no difference in frequency of septal fibrosis (60% in group B vs 48% in group BC, P = .46) or interface hepatitis (73% vs 71%, P = .99).

CONCLUSIONS

HBV-HCV coinfection was related to a longer time on hemodialysis, longer duration of infection, and history of blood transfusion. Contrary to nonuremic patients, HCV coinfection was not associated with more severe forms of liver disease in ESRD patients.

High prevalence of low bone mineral density in pre-dialysis chronic kidney disease patients: bone histomorphometric analysis

Chronic kidney disease (CKD) leads to reduced bone mineral density (BMD) in pre-dialysis and dialysis patients. A few studies have used dual-energy x-ray absorptiometry (DEXA) to assess BMD in pre-dialysis CKD patients and have shown low BMD to be highly prevalent. Until now there have been no studies reporting the histological features of low BMD in pre-dialysis CKD patients.

AIM

To determine the prevalence and histological features of low BMD in pre-dialysis CKD patients.

METHOD

Pre-dialysis CKD patients (n = 103, 46 females/57 males), median creatinine clearance of 29 (10 - 78) ml/min/ 1.73 m2, were evaluated using biochemical analysis and DEXA. Bone biopsies were obtained from those with low BMD.

RESULTS

Fifty (48.5%) out of the 103 patients had low BMD (LBD group) and 53 (51.5%) had normal BMD (NBD group). The risk for low BMD was increased in those patients with alkaline phosphatase levels above 190 U/l and intact-PTH (iPTH) below 70 pg/ml (p < 0.05). Demographic and biochemical parameters from both groups were comparable, except for lower body mass index (BMI) in LBD subjects (p = 0.04). Women who had been post-menopausal for at least 1 year comprised 65% (13/20) and 50% (13/26) of the LBD and NBD groups, respectively (p = NS). In 40 LBD patients, bone histomorphometry revealed adynamic bone disease (ABD, 52.5%), osteomalacia (OM, 42.5%) and mixed bone disease (MBD, 5%). Trabecular bone volume (BV/TV) was lower in ABD and OM patients. A nearly significant association was found between ABD and iPTH < or = 150 pg/ml (p = 0.056), whereas higher values of iPTH were associated with OM. Total alkaline phosphatase < or = 190 U/l was significantly associated with ABD, whereas higher values were associated with OM. No correlation was observed between BV/TV and BMD.

CONCLUSION

Low BMD is frequent in pre-dialysis CKD patients, and low turnover bone disease, manifesting as ABD and OM, was the hallmark of this bone loss.

Customized bicarbonate buffered dialysate and replacement solutions for continuous renal replacement therapies: effect of crystallization on the measured levels of electrolytes and buffer

The aim of this study was to investigate the impact of the addition of calcium to bicarbonate solutions for continuous renal replacement therapy (CRRT). We tested single bag (bicarbonate and calcium mixed 24 h before testing) and double bag solutions (mixed immediately before) with and without the addition of 4 mEq/L of acetate. Prescribed calcium varied from 0 to 5 mEq/L. All test solutions containing calcium showed crystallization at light microscopy. The double bag solutions decreased but did not prevent crystallization. The addition of acetate did not interfere with crystallization. Crystallization, as measured by the weight of the crystals after filtration of the solutions, showed a significant positive correlation with the calcium deficit (prescribed minus measured) and with partial pressure of carbon dioxide. The measured level of calcium was lower than expected and correlated with crystallization. Our results suggest that the use of bicarbonate solutions containing calcium as replacement fluids for CRRT is a potentially unsafe procedure.

Parathyroid hormone changes during phosphorus load in patients with chronic renal insufficiency with low serum parathyroid hormone or adynamic bone disease

Adynamic bone disease (ABD) is frequently associated with low serum parathyroid hormone (PTH) concentrations. Many clinical and therapeutic conditions have been associated with ABD, and recently, a low phosphorus intake accompanied by low serum concentration of phosphorus and PTH has been described.

AIM

To evaluate the parathyroid gland response of chronic renal insufficiency patients (CRI) with low serum PTH or ABD to a phosphorus load.

METHODS

We examined the effects of 0.5 and 1.0 g/d of phosphorus load over a period of 60 days in 18 patients with mild CRI with a bone biopsy showing ABD (n = 7) or with low serum PTH (serum intact PTH < or = 40 ng/l) and serum phosphorus < 4.5 mg/dl (n = 11).

RESULTS

Serum intact PTH increased significantly only after 1 g of phosphorus (58.5 to 83 ng/l) with a median percent increase of 72%. PTH secretion increased more in patients with lower basal PTH levels (81%). Serum phosphorus did not change significantly and urinary phosphorus increased from 487 to 1,062 mg/dl (p < 0.05). Significant decreases in serum ionized calcium (from 1.26 to 1.19 mmol/l) and calcitriol (from 34.5 to 24.9 pg/ml) were observed. Changes in PTH were inversely correlated with changes in serum ionized calcium (r = -0.54, p < 0.05) and the final PTH concentrations were positively correlated with changes in serum phosphorus (r= 0.52, p < 0.05).

CONCLUSIONS

The parathyroid glands of chronic renal insufficiency patients with "relative hypoparathyroidism" or ABD responded to a phosphorus load with an increase in serum PTH levels. The decrease in serum ionized calcium and calcitriol as well as minimal changes in serum phosphorus appeared to be involved in this response.

Resting energy expenditure in pre-dialysis diabetic patients

BACKGROUND

The metabolic derangements of diabetes mellitus (DM) associated with those of chronic renal failure (CRF) may interfere with the energy and protein balance of patients with both diseases. The aim of this study was to verify whether the resting energy expenditure (REE) of non-dialysis chronic renal failure diabetic patients differs from that of chronic renal failure patients without DM.

METHODS

REE was measured by indirect calorimetry in 24 CRF diabetic patients (CRF diabetes group), matched for age, gender, and degree of renal impairment to 24 CRF patients without DM (CRF control group).

RESULTS

The CRF diabetes group had a significantly higher REE (1538+/-230 kcal/day) than the CRF control group (1339+/-315 kcal/day, P = 0.009). This difference was maintained even when the REE was adjusted for lean body mass (LBM; 30.3+/-4.3 vs 26.3+/-5.4 kcal/kg LBM/day, P = 0.004). Mean protein intake was significantly higher in the CRF diabetes than in the CRF control group (0.89+/-0.20 vs 0.76+/-0.25 g/kg/day, P = 0.02). Mean protein equivalent of nitrogen appearance (PNA) was also significantly higher in the CRF diabetes patients (1.21+/-0.31 vs 1.03+/-0.22 g/kg/day, P = 0.02), reflecting a higher protein intake and/or elevated protein breakdown. Accordingly, REE was directly correlated with PNA mainly in the CRF diabetes group (r = 0.57, P < 0.003).

CONCLUSION

Metabolic disturbances of poorly controlled DM may account for the higher REE observed in the CRF diabetes group. The role of the apparently higher protein breakdown in this increased REE remains to be clarified.

Apoptosis of leukocytes: basic concepts and implications in uremia

Circulating blood leukocytes have short life expectancies and end their lives by committing programmed cell death or apoptosis. Apoptosis is an active form of cell death that is initiated by a number of stimuli and is intricately regulated. Apoptosis in both excessive and reduced amounts has pathological implications. Evidence suggests that apoptosis may play a role in the pathophysiology of immune dysfunction in uremia. Indeed, accelerated programmed cell death has been observed in lymphocytes, monocytes, and polymorphonuclear leukocytes among patients with chronic renal failure. This may be due in part to the retention of uremic toxins. The aim of this article is to review the evidence for accelerated leukocyte apoptosis, key regulatory apoptotic pathways, and the possible role of this highly organized process in the pathogenesis of immune dysfunction in uremia.

Nutritional status of hemodialysis patients with secondary hyperparathyroidism

The repercussions of secondary hyperparathyroidism on the nutritional status of chronic renal failure patients have not been well established. Therefore, the aim of this study was to compare the nutritional indices of hemodialysis patients with and without secondary hyperparathyroidism. Sixteen hemodialysis patients with serum parathyroid hormone (PTH) levels higher than 420 pg/ml (hyperparathyroidism group) were matched for gender, age and length of dialysis treatment to 16 patients with serum PTH between 64 and 290 pg/ml (control group). The following parameters were assessed: anthropometric indices (body mass index, skinfold thickness, midarm muscle circumference and body fat), 4-day food diaries, protein catabolic rate, biochemical indices (blood urea nitrogen, serum creatinine, albumin, ionized calcium, inorganic phosphorus, serum alkaline phosphatase, PTH, pH and HCO(3)) and dialysis efficiency. We did not observe differences in the anthropometric indices between the two groups. Only calcium intake was significantly different between groups (307.9 mg/day for the hyperparathyroidism group vs 475.8 mg/day for the control group). Protein catabolic rate tended to be higher in the hyperparathyroidism group compared to the control group (1.3 vs 0.9 g kg(-1) day(-1); P = 0.08). Except for blood urea nitrogen (86.4 vs 75.7 mg/dl), alkaline phosphatase (175 vs 65 U/l) and PTH (898 vs 155 pg/ml), no other differences were found between groups in the biochemical indices studied. PTH was directly correlated with protein catabolic rate (r = 0.61; P<0.05) and length of dialysis (r = 0.53; P<0.05) only in the hyperparathyroidism group. Considering the indices used, we could not demonstrate the deleterious effect of high PTH levels on the nutritional status of hemodialysis patients. Indirect evidence, however, suggests an action of PTH on protein metabolism.

New polyether sulfone dialyzers attenuate passage of cytokine-inducing substances from pseudomonas aeruginosa contaminated dialysate

The use of bicarbonate dialysate and high-flux and reprocessed dialyzers has raised concerns about the reverse transfer of dialysate contaminants into the blood compartment. This in vitro study was performed to investigate the reverse transfer of soluble Pseudomonas aeruginosa bacterial products across a polyether sulfone (PES), a newly developed synthetic polymer dialyzer. In vitro dialysis was carried out at 37 degreesC in a closed countercurrent recirculating loop dialysis circuit with a new PES dialyzer. An equal mixture of heparinized whole blood (from healthy volunteers) with pyrogen-free tissue culture medium was circulated in the blood compartment, and bicarbonate dialysate was circulated in the dialysate compartment. After 15 min of dialysis, the dialysate was challenged sequentially with 10(-4), 10(-3), and 10(-2) dilutions of a P. aeruginosa culture supernatant. 1-ml samples were drawn from the blood compartment 5 and 15 min after each challenge and incubated upright at 37 degrees C. At the end of 24 h, Triton X-100 was added, in order to extract total interleukin (IL) 6 and IL-8 production by the whole-blood mixture. These cytokines were measured by electrochemiluminescence assays. At dilutions of 10(-4) and 10(-3), the reverse transfer of soluble bacterial products across the dialyzer was negligible. Five and 15 min after contaminating the dialysate with the highest concentration (10(-2) dilution), the increase in IL-6 production was 239 +/- 170% (p = 0.06) and 886 +/- 444% (p = 0.02), respectively. However, comparing the IL-6-inducing potency of the 10(-2) bacterial supernatant dilution to the spontaneous IL-6 production in the blood compartment during dialysis with the same dilution of dialysate contaminant, there was a dramatic reduction in IL-6 production by 94 and 89% at 5 and 15 min, respectively. Similarly, 5 and 15 min after contaminating the dialysate with the 10(-2) dilution, the increase in IL-8 production was 357 +/- 147% (p = 0.07) and 630 +/- 229% (p = 0.04), respectively. However, comparing the IL-8-inducing potency of the 10(-2) bacterial supernatant dilution to the spontaneous IL-8 production in the blood compartment during dialysis with the same dilution of dialysate contaminant, there was a dramatic reduction in IL-8 production by 93 and 92% at 5 and 15 min, respectively. These results demonstrate that PES dialyzers markedly attenuate passage of cytokine-inducing substances from contaminated dialysate, using a method that detects the entire cytokine synthetic output in the blood compartment.

Impact of dialyzer membrane selection on cellular responses in acute renal failure: a crossover study

BACKGROUND

When acute renal failure (ARF) is severe enough to require dialysis, in-hospital mortality rates approach 60%. These alarming figures have been ascribed in part to advanced age and the high prevalence of comorbid conditions. In the past several years, a number of attempts have been made to investigate the impact of dialyzer membrane type on clinical outcomes. Unfortunately, to date, clinical studies addressing this question have reported conflicting results.

METHODS

This crossover study examined the effect of dialyzer membrane type on cytokine synthesis by peripheral blood mononuclear cells (PBMCs), superoxide release by neutrophils, and apoptosis or programmed cell death of neutrophils in 24 patients with ARF requiring intermittent hemodialysis. The patients were assigned in an alternate order to a low-flux cellulose acetate (CA) or polysulfone (PS) dialyzer. After three consecutive dialysis sessions, patients were crossed over to the second dialyzer for three additional treatments. These cellular responses were measured upon dialyzer assignment and at the third and sixth dialysis session in relationship to the dialyzer type.

RESULTS

The results of the study showed no impact of dialyzer biocompatibility on synthesis of tumor necrosis factor-alpha (TNF-alpha) or interleukin 10 (IL-10) by PBMCs, superoxide release by neutrophils, or neutrophil apoptosis. This held true regardless of the initial dialyzer assignment. Furthermore, there was no correlation between dialysis adequacy (measured by single-pool Kt/V) and postdialysis cellular responses.

CONCLUSIONS

In summary, this study refines the question of biocompatibility by comparing a substituted cellulose rather than unsubstituted cellulose dialyzer to a PS dialyzer in the setting of ARF. The results failed to demonstrate a dialyzer advantage on the selected cellular responses.

Quality of life at the initiation of maintenance dialysis treatment--a comparison between the SF-36 and the KDQ questionnaires

OBJECTIVE

To evaluate the construct validity of the Medical Outcomes Study Questionnaire 36-Item Short Form Health Survey (SF-36) and to assess the quality of life of patients with end-stage renal disease (ESRD) at the initiation of maintenance dialysis treatment.

METHODS

Cross-sectional study.

SETTING

Eight ambulatory dialysis units in São Paulo city, Brazil.

STUDY PARTICIPANTS

Eighty ESRD patients at the initiation of chronic dialysis program and consecutively accepted for treatment in selected units in 1998.

MAIN OUTCOME MEASURES

Quality of life as measured by the dimensions of the SF-36 questionnaire. The 'Kidney Disease Questionnaire' was used in a subgroup of patients to evaluate the validity of the SF-36.

RESULTS

Median (range) scores of the SF-36 dimensions (ranging from 0 to 100, higher scores representing better quality of life) were: Physical Function 70 (0-100), Role Limitations due to Physical Problems 25 (0-100), Bodily Pain 62 (0-100), General Health 57 (5-100), Vitality 55 (10-100), Social Function 63 (0-100), Role Limitations due to Emotional Problems 34 (0-100) and Mental Health 68 (0-100). SF-36 dimensions correlated significantly with those of the 'Kidney Disease Questionnaire' (correlation coefficients ranging from 0.23 to 0.68).

CONCLUSIONS

The SF-36 was shown to have construct validity when used in patients with ESRD in Brazil. The quality of life of ESRD patients is impaired at the initiation of dialysis treatment and this was clearly evidenced in the Role Limitations due to Physical Function and Emotional Function items. Greater attention should be given to interventions that could improve the quality of life parameters at the initiation of dialysis treatment.

Shiga toxin induces superoxide production in polymorphonuclear cells with subsequent impairment of phagocytosis and responsiveness to phorbol esters

The role of inflammatory cells in the pathogenesis of hemolytic-uremic syndrome induced by Shiga toxin (Stx)-producing Escherichia coli remains unclear. The hypothesis that Stx has direct effects on polymorphonuclear cell (PMN) viability and function was examined by measuring apoptosis, necrosis, phagocytosis, and spontaneous and phorbol myristate acetate (PMA)-stimulated production of reactive oxygen intermediates. PMN from 6 healthy persons were exposed to medium, Stx1 (0.01-100 ng/mL), or heat-inactivated Stx1 or Stx1 B subunit (100 ng/mL). Stx1 induced a prominent dose-dependent respiratory burst from PMN at doses as low as 0.01 ng/mL; they were less responsive to PMA stimulation and had reduced ability for phagocytosis. This dysfunction was not due to cell death, as the magnitude of apoptosis and necrosis of PMN treated with Stx1 (100 ng/mL) for 20 h was identical to that of medium control. These results suggest that Stx has direct effects on PMN that could contribute to tissue injury early in the disease.

Neutrophil apoptosis and dysfunction in uremia

The high prevalence of bacterial infections among patients with end-stage renal disease suggests that "professional" phagocytes such as neutrophils are functionally impaired. This dysfunction has been ascribed to uremic toxins, malnutrition, and dialysis. The aim of this study was to investigate the contribution of apoptosis to neutrophil dysfunction in uremia. Neutrophils harvested from uremic patients (n = 6) and age-/gender-matched healthy control subjects (n = 6) were incubated with either 50% autologous plasma or 10% fetal calf serum. After 24-h incubation, apoptosis was quantified by flow cytometry by using propidium iodide nuclear staining. Neutrophils from healthy volunteers were also incubated with either 50% heterologous normal or uremic plasma. After 24-h incubation, apoptosis was quantified by flow cytometry and transmission electron microscopy. In addition, superoxide production was determined by measuring the capacity to reduce ferri- to ferro-cytochrome C by using 4-beta-phorbol 12-beta-myristate 13-alpha-acetate or N-formyl methionyl-leucyl-phenylalanine (fMLP) for stimulus. Phagocytosis was determined by the uptake of 14C-labeled heat-killed Staphylococcus aureus. Compared with normal neutrophils, uremic neutrophils demonstrated greater apoptosis in the presence of autologous plasma (9 +/- 4 versus 19 +/- 6%, P = 0.01) as well as 10% fetal calf serum (19 +/- 7 versus 31 +/- 6%, P = 0.03). Furthermore, compared with normal neutrophils exposed to heterologous normal plasma, those exposed to heterologous uremic plasma exhibited higher apoptosis rates (19 +/- 3 versus 40 +/- 5%, P = 0.002), lower tMLP-stimulated superoxide production (22.6 +/- 2.5 versus 15.5 +/- 1.1 nmol O2*-/3.12 x 10(5) cells/30 min, P = 0.01), and a lower phagocytosis index (38 +/- 3% versus 27 +/- 5%, P = 0.04). Apoptosis correlated inversely with fMLP-stimulated superoxide production (r = -0.60, P = 0.04) and phagocytosis (r = -0.57, P = 0.05). These results suggest that uremic neutrophils undergo accelerated in vitro apoptosis. Furthermore, uremic plasma accelerates apoptosis of normal neutrophils, resulting in a dysfunctional pattern that is similar to that observed in uremia.

Interleukin-1 receptor antagonist synthesis by peripheral blood mononuclear cells in hemodialysis patients

BACKGROUND

Pro-inflammatory cytokines like interleukin (IL)-1 beta and tumor necrosis factor-alpha (TANF-alpha) are believed to play a significant role in dialysis-related morbidity. It has been previously demonstrated that the endogenous synthesis of interleukin-1 receptor antagonist (IL-1Ra) is a reliable marker of the level of IL-1 beta synthesis in hemodialysis (HD) patients. In this study, we assessed the impact of clinical and laboratory variables on IL-1Ra synthesis by peripheral blood mononuclear cells (PBMC) in patients on HD with unsubstituted cellulose dialyzers.

METHODS

IL-1Ra by PBMC was measured by a specific non-cross-reactive radioimmunoassay. Day to day variation in cytokine synthesis, the correlation between cytokine synthesis under different in vitro stimulatory conditions, and the influence of clinical and laboratory variables on cytokine synthesis were studied.

RESULTS

Although there was a trend towards greater IL-1Ra synthesis by unstimulated, endotoxin-stimulated and IgG-stimulated PBMC drawn before the second and third dialysis sessions of the week when compared to the first dialysis treatment, this was not statistically significant. There was a strong correlation between IL-1Ra synthesis by PBMC cultured under different stimulatory conditions that was best observed between IL-1Ra cell content and from endotoxin-stimulated PBMC (r = 0.51, P = 0.0001), and endotoxin- and IgG-stimulated PBMC (r = 0.44, P = 0.0001). In addition, there was a close correlation between total synthesis (cell associated and secreted) and secreted levels of IL-1Ra in unstimulated (r = 0.59, P = 0.0001) and endotoxin-stimulated PBMC (r = 0.69, P = 0.0001). Interestingly, there was an inverse correlation between IL-1Ra synthesis and duration of dialysis that was strongest for secreted IL-1Ra from unstimulated (r = -0.50, P = 0.002) and endotoxin-stimulated PBMC (r = -0.34, P = 0.04). There was no significant correlation between IL-1Ra synthesis by PBMC and other clinical and laboratory indices.

CONCLUSIONS

The observations from this study indicate that: (1) in HD patients, there were no significant differences in cytokine synthesis by PBMC drawn before the three different dialysis treatments during the week; (2) there is a close relationship between IL-1Ra synthesis from PBMC cultured under different stimulatory conditions; (3) the secreted levels of IL-1Ra correlate directly with total synthesis (cell-associated and secreted); (4) with the exception of duration of dialysis, none of the other clinical or laboratory parameters correlated with cytokine synthesis; and (5) the diminished endotoxin- or IgG-stimulated IL-1Ra synthesis with increasing time on dialysis is possibly another sign of the impaired host-defense system in patients on long-term hemodialysis.

Effect of glucose concentration, osmolality, and sterilization process of peritoneal dialysis fluids on cytokine production by peripheral blood mononuclear cells and polymorphonuclear cell functions in vitro

We sought to investigate the effects of high glucose concentration, osmolality, and heat sterilization of peritoneal dialysis fluids on tumor necrosis factor-alpha (TNF-alpha) production by peripheral blood mononuclear cells (PBMC) and polymorphonuclear cell (PMN) functions. Blood samples were obtained from eight healthy volunteers. PBMCs and PMNs were harvested by centrifugation with Ficoll-Hypaque (Sigma, St Louis, MO). PBMC were incubated with an equal volume of test fluids and RPMI for 4 hours (pH equilibrated), followed by incubation for 20 hours in RPMI with or without endotoxin (10 ng/mL). Total TNF-alpha production was measured by radioimmunoassay. PMNs were incubated with pH-adjusted test fluids for 30 minutes. After incubation, phagocytosis was determined by the uptake of 14C-labeled Staphylococcus aureus, oxidative burst by reduction of ferricytochrome C to ferrouscytochrome C on stimulation with phorbol myristate acetate, and enzyme release by measurement of endotoxin-stimulated bactericidal/permeability increasing factor. To study the effects of increasing glucose concentration and osmolality on PBMC and PMN functions, we compared conventional 1.5% Dianeal (1.5%D), (Baxter Healthcare Corp, Deerfield, IL) 2.5% Dianeal (2.5%D), 4.25% Dianeal (4.25%D), and control (RPMI for PBMCs and Hank's balanced salt solution for PMNs). PMNs exposed to 4.25%D exhibited an inhibition of phagocytosis, phorbol myristate acetate (PMA)-stimulated oxidative burst, and bactericidal/permeability increasing factor release compared with control, 1.5%D, or 2.5%D. To study the effects of increased osmolality when controlled for glucose concentration, we compared 1.5%D with 1.5%D in which osmolality was increased to that of 4.25%D with the addition of either sodium chloride (1.5%D+NaCl) or mannitol (1.5%D+M). High osmolality induced higher TNF-alpha production by unstimulated PBMCs and decreased TNF-alpha production by endotoxin-stimulated PBMCs. PMN functions were also inhibited by high osmolality. To study the effects of increased glucose concentration when controlled for osmolality, we compared 4.25%D with 1.5%D+NaCl and 1.5%D+M. High glucose concentration induced an increase in TNF-alpha production by unstimulated PBMCs, a decrease in TNF-alpha production by endotoxin-stimulated PBMCs, and an inhibition of PMN functions. Finally, to investigate the effects of heat sterilization, we compared 4.25%D (heat sterilized) to a filter-sterilized 4.25%D (4.25%D-F). The filter-sterilized fluid induced less changes in PBMC and PMN functions compared with the heat-sterilized fluid. These data suggest that the high glucose concentration, high osmolality, and heat sterilization of peritoneal dialysis fluids adversely affect PBMC and PMN functions. These effects could predispose continuous ambulatory peritoneal dialysis patients to peritonitis, compromise host defense during infection, and jeopardize long-term survival of the peritoneal membrane.

Necrosis and apoptosis of polymorphonuclear cells exposed to peritoneal dialysis fluids in vitro

Conventional peritoneal dialysis (PD) fluids are known to inhibit polymorphonuclear cells (PMN) phagocytosis, oxidative burst and enzyme release. However, the relative contributions of apoptosis and/or necrosis to this dysfunction have not been examined. We investigated the effects of osmolality, glucose concentration and heat-sterilization of PD fluids on necrosis and apoptosis of PMN. Polymorphonuclear cells were isolated from 8 healthy volunteers and exposed to different PD fluids for four hours. PMN were then double-stained with Hoechst 33342 and propidium iodide to study the proportion of viable, apoptotic and necrotic cells. Transmission electron microscopy (TEM) was performed to confirm the results obtained with flow cytometry. The fluids studied were conventionally heat-sterilized 1.5% Dianeal (1.5% D), conventionally heat-sterilized 4.25% Dianeal (4.25% D), 1.5% D in which the osmolality was increased to that of 4.25% D by adding mannitol (1.5% D + M), a filter-sterilized version of 4.25% D (4.25% D-F) and a 1.1% amino acid PD fluid (AA) (Nutrineal PD4). All PD fluids had their pH equilibrated (pH = 7.4) by the addition of sodium bicarbonate. Compared to PMN exposed to culture medium, a significantly higher proportion of necrosis was observed in PMN exposed to 1.5% D (P = 0.04). The 4.25% D induced greater necrosis than 1.5% D (P = 0.001), and the 4.25% D also induced significantly more necrosis (P = 0.002) compared to 4.25% D-F. These data suggest that the consequences of heat-sterilization, rather than high glucose concentration are responsible for the necrosis observed. Indeed, the proportion of necrotic PMN with 4.25% D-F was not significantly different from 1.5% D. The 1.5% D + M and AA induced significantly more apoptosis compared to 1.5% D (P = 0.006 and P < 0.05, respectively), suggesting that apoptosis can be induced by the high osmolality of PD fluids. However, 1.5% D +/- M also induced significantly more apoptosis (P = 0.007) compared to 4.25% D-F. This suggests that the apoptosis effect is specific for the osmolyte present in PD fluids, and that mannitol and amino acids induce more apoptosis than glucose. In summary, the different non-physiological components of conventional PD fluids evaluated in this study had a differential effect on PMN survival. Heat sterilization of high glucose-containing PD fluids was associated predominantly with necrosis of PMN, and high osmolality with apoptosis.

Effect of two-chambered bicarbonate lactate-buffered peritoneal dialysis fluids on peripheral blood mononuclear cell and polymorphonuclear cell function in vitro

Low pH, high osmolality, increasing glucose concentration, and glucose degradation products (GDP) formed during heat sterilization of conventional peritoneal dialysis (PD) fluids have been shown to have a detrimental effect on cells involved in peritoneal host defense. The two-chambered PD fluid bag in which glucose at pH approximately 3 is separated from a bicarbonate (25 mmol/L)-lactate (15 mmol/L) buffer during heat sterilization permits PD fluids with lower GDP to be delivered to the patient at neutral pH. To establish the possible benefit of two-chambered bag PD fluids on peripheral blood mononuclear cell (PBMC) and polymorphonuclear (PMN) cell function, we compared conventional 1.5% Dianeal (1.5%D) with 1.5% two-chambered bag bicarbonate-lactate (1.5%D-B), and conventional 4.25% Dianeal (4.25%D) with 4.25% two-chambered bag bicarbonate-lactate (4.25%D-B). Furthermore, to study the effect of the sterilization process on PBMC and PMN function, we compared filter-sterilized 4.25%D (4.25%D-F) with 4.25%D and 4.25%D-B. PBMC were harvested by Ficoll-Hypaque separation, and 2.5 x 10(6) cells in RPMI were incubated with an equal volume of the test fluids for 4 hours, pelleted, and resuspended in RPMI containing 10 ng endotoxin for a further 20 hours. Tumor necrosis factor alpha (TNF-alpha) production by endotoxin-stimulated PBMC was not significantly different (P = 0.10) between 1.5%D-B and 1.5%D, but was significantly higher (P = 0.01) with 4.25%D-B compared with 4.25%D. PBMC exposed to filter-sterilized fluid (4.25%D-F) showed significantly higher endotoxin-stimulated TNF-alpha production compared with 4.25%D (P = 0.02), but was not significantly different from 4.25%D-B (P = 0.40). PMN were harvested by Ficoll-Hypaque separation and 10 x 10(6) cells incubated with test fluids for 30 minutes. After incubation, phagocytosis (phagocytosis index) was determined by the uptake of 14C-labeled Staphylococcus aureus, oxidative burst by reduction of ferricytochrome C to ferrocytochrome C on stimulation with PMA, and enzyme release by measurement of endotoxin-stimulated bactericidal/permeability increasing protein (BPI). Bicarbonate-lactate two-chambered fluids of similar osmolality and glucose concentration conferred a significant improvement in phagocytosis (P = 0.02 for 1.5%D-B and P < 0.001 for 4.25%D-B). Oxidative burst and BPI release were significantly higher in 4.25%D-B compared with 4.25%D (P < 0.001). Filter-sterilized 4.25%D-F conferred a significant improvement in phagocytosis and oxidative burst compared with 4.25%D (P < 0.001) or 4.25%D-B (P < 0.001). Furthermore, conventional 4.25%D was associated with significantly lower BPI release compared with 4.25%D-F (P = 0.01). GDP's acetaldehyde and 5-HMF were analyzed in 4.25%D-B, 4.25%D, and 4.25%D-F. Acetaldehyde was below the lower limit (0.79 ppm) of the standard curve in 4.25%D-B and 4.25%D-F fluids but was detected (3.76 to 5.12 ppm) in all of the 4.25%D fluids. Relative levels of 5-HMF in the 4.25%D-B (0.032 to 0.041 Abs @ 284 nm) and 4.25%D (0.031 to 0.036 Abs @ 284 nm) were similar. The lowest levels (0.001 Abs @ 284 nm) were observed in the filter-sterilized 4.25%D-F. The beneficial effects of two-chambered bicarbonate lactate-buffered PD fluids on PBMC and PMN function are probably related to reduction of GDP from heat sterilization of glucose in a separate chamber at a lower pH. This improvement in biocompatibility could have a beneficial affect on peritoneal defenses.

Effect of sodium fusidate and ofloxacin on Staphylococcus aureus colonization and infection in patients on continuous ambulatory peritoneal dialysis

The effectiveness of sodium fusidate and ofloxacin to eliminate nasal and catheter exit-site Staphylococcus aureus colonization and to prevent infections was compared in 31 patients on continuous ambulatory peritoneal dialysis (CAPD). In a prospective randomized study, 9 patients were treated with topical 2% sodium fusidate ointment applied in the anterior nares and in the pericatheter skin twice daily for 5 days; 9 subjects received oral ofloxacin 200 mg taken every 48 hours for 5 days and 13 subjects were in the control group. Treatment courses were repeated at one-month intervals. Mean duration of follow-up was 7.8 months (242 patients-month). Follow-up samples from the nares and the catheter exit-site were obtained every month from all participants to determine the presence of S. aureus. Development of S. aureus exit-site infection and peritonitis were assessed. During the study, S. aureus was recovered from 45%, 59% and 52% of the samples from the nares and/or exit-site in the sodium fusidate, ofloxacin and control groups, respectively (p = 0.13). S. aureus grew less frequently (p < 0.01) in samples from the exit-site in the sodium fusidate than in the other two groups. Eradication of nasal colonization (two negative cultures within one month) was observed in 43%, 40% and 33% of the cases in the sodium fusidate, ofloxacin and control groups, respectively (p > 0.50). The corresponding figures for exit-site eradication were 43%, 33% and 11%, respectively (p = 0.34). Twenty-four S. aureus-associated infection episodes (12 of exit-site and 12 of peritonitis) were diagnosed in 16 of the 31 patients.(ABSTRACT TRUNCATED AT 250 WORDS)