High blood soluble receptor p80 for tumour necrosis factor-alpha is associated with erythropoietin resistance in haemodialysis patients

Effects of the inspiratory muscle training and aerobic training on respiratory and functional parameters, inflammatory biomarkers, redox status and quality of life in hemodialysis patients: A randomized clinical trial

Objective

Evaluate and compare the isolated and combined effects of Inspiratory Muscle Training (IMT) and Aerobic Training (AT) on respiratory and functional parameters, inflamatory biomarkers, redox status and health-related quality of life (HRQoL) in hemodialysis patients.

Methods

A randomised controlled trial with factorial allocation and intention-to-treat analysis was performed in hemodialysis patients. Volunteers were randomly assigned to performe 8-weeks of IMT at 50% of maximal inspiratory pressure (MIP), low intensity AT or combined training (CT). Before the interventions, all the volunteers went 8-weeks through a control period (without training). Measures are taken at baseline, 8-week (after control period) and 16-week (after the interventions). Primary outcomes were functional capacity (incremental shuttle walk test), MIP and lower limbs strength (Sit-to-Stand test of 30 seconds). Plasma levels of interleukin-6 (IL-6), soluble tumor necrosis factor receptor 1 (sTNFR1) and 2 (sTNFR2), adiponectin, resistin and leptin, redox status parameters and HRQoL (KDQOL-SF questionnaire) were the scondary outcomes. Data analyses were performed by two-way repeated measurements ANOVA.

Results

37 hemodialysis patients aged 48.2 years old (IC95% 43.2–54.7) were randomized. Increase of MIP, functional capacity, lower limbs strength and resistin levels, and reduction of sTNFR2 levels in 16-week, compared to baseline and 8-week, were observed in all the groups (p<0.001). IMT improved functional capacity, MIP and lower limbs strength in 96.7m (IC95% 5.6–189.9), 34.5cmH₂O (IC95% 22.4–46.7) and 2.2repetitions (IC95% 1.1–3.2) respectively. Increase in resistin leves and reduction in sTNFR2 leves after IMT was 0.8ng/dL (IC95% 0.5–1.1) and 0.8ng/dL (IC95% 0.3–1.3), respectively, without between-group differences. Compared to baseline and 8-week, adiponectin levels (p<0.001) and fatigue domain of the HRQoL (p<0.05) increased in 16-week only in CT.

Conclusion

IMT, AT and CT improved functional parameters and modulated inflammatory biomarkers, in addition, IMT provoked a similar response to low intensity AT in hemodialysis patients.

Trial registration

Registro Brasileiro de Ensaios clínicos RBR-4hv9rs.

Peripheral blood mononuclear cell-derived erythroid progenitors and erythroblasts are decreased in burn patients

Patients with large burns suffer from anemia of critical illness. Administration of exogenous erythropoietin is ineffective, and transfusion remains the only effective treatment. We have previously shown that erythroid precursors are decreased 1 week after burn in an animal model. Therefore, we have used a two-phase liquid culture system to quantify peripheral blood mononuclear cell (PBMC) compartment-derived erythroid progenitors (EPs) in burn patients. Institutional review board approval and informed consent were obtained. Blood samples were collected at 1 to 30 days after burn, with a mean TBSA of 37.7 ± 15.8% (n = 10; 90% men; age, 46.0 ± 18 years). Four healthy volunteers served as controls. PBMCs were isolated by Ficoll-Hypaque density-gradient centrifugation and were placed in serum-free expansion medium containing cyclosporine A (1 ng/ml), granulocyte macrophage colony-stimulating factor (20 ng/ml), stem cell factor (30 ng/ml), and interleukin-3 (5 ng/ml; phase I). On day 7, cells were reseeded in serum-free expansion medium containing erythropoietin (1 U/ml), holotransferrin (0.3 mg/ml), and stem cell factor (10 ng/ml; phase II). Aliquots from the phase II culture system on day 6 were incubated with anti-CD71, CD235a, and CD36. EPs (CD71 CD36) and erythroblast subpopulations (colony-forming unit erythroids, Proerythroblasts, and intermediate erythroblasts) were identified based on the expressions of CD71 and CD235a by flow cytometry, calculated per million expanded cells, and expressed as a percentage of controls. Total EPs were significantly decreased by days 28 to 31 after the burn (19%; P < .05). Among the erythroblast subpopulations, colony-forming unit erythroids (11%; P < .004) and proerythroblasts (24%; P < .05), were decreased significantly by days 28 to 31 after the burn. PBMCs of burn patients can be used to study impaired erythropoiesis and anemia of critical illness.

Iron homeostasis in chronic inflammation

Inflammation induced anemia and resistance to erythropoietin are common features in patients with chronic kidney disease (CKD). Elevated levels of cytokines and enhanced oxidative stress, conditions associated with inflammatory states, are implicated in the development of anemia. Accumulating evidence suggests that activation of cytokine cascade and the associated acute-phase response, as it often occurs in patients with CKD, divert iron from erythropoiesis to storage sites within the reticuloendothelial system leading to functional iron deficiency and subsequently to anemia or resistance to erythropoietin. Other processes have also been shown to be involved in the pathogenesis of anemia provoked by the activated immune system including an inhibition of erythroid progenitor proliferation and differentiation, a suppression of erythropoietin production and a blunted response to erythropoietin. The present review concerns the underlying alterations in iron metabolism induced by chronic inflammation that result in anemia.

Do We Know the Correct Hemoglobin Target for Anemic Patients with Chronic Kidney Disease?: Table 1

The major objectives of this article are to review hemoglobin outcome studies, focusing on the utility of purely observational approaches; the design limitations of hemoglobin target randomized trials; what is known from the trials that have been performed to date; and whether confident recommendations for target ranges can be made. The commonly observed association among lower hemoglobin levels, left ventricular hypertrophy, and higher mortality also has been seen within randomized trials when assigned hemoglobin targets were ignored; critically, however, corresponding relationships were absent when intention-to-treat principles were used, strongly suggesting noncausal associations and the need for randomized designs. This being said, hemoglobin typical target trials often have undesirable features, including inadequate blinding and the use of imbalanced, nonstandardized, nonblinded co-interventions. The trials published to date, spanning hemoglobin levels of approximately 7 to 13 g/dl, suggest that higher treatment targets enhance quality of life but at the price of higher BP, thrombotic events, and reduced dialysis adequacy in hemodialysis patients. To date, there is no convincing evidence that targets that approach the physiologic range (versus intermediate targets) have an effect on left ventricular size or survival. Therefore, depending on the outcome examined, higher hemoglobin levels may have beneficial effects, harmful effects, or no effect, leading to the unsatisfactory situation of having to make opinion-based tradeoff decisions. Whereas the available evidence suggests that 11 g/dl is a reasonable lower bound for the hemoglobin target range, the upper bound remains to be defined and targets above 13 g/dl cannot be routinely recommended.

Anaemia and mortality in haemodialysis patients: interaction of propensity score for predicted anaemia and actual haemoglobin levels

BACKGROUND

Haemoglobin levels in haemodialysis patients could represent unknown comorbidities, more severe levels of known comorbidities, as well as therapeutic choice. Thus, integrating factors predictive of anaemia with actual haemoglobin levels might improve prognostic discrimination.

METHODS

We retrospectively studied 93,087 patients who started haemodialysis between 1998 and 2000. Clinical and treatment factors from months 4 through 9, derived from Medicare claims, were used to develop propensity scores for anaemia (mean haemoglobin <11 g/dl). Tertiles of propensity scores were interacted with five levels of actual mean haemoglobin to form 15 groups, ranging from low (anaemia) probability with (mean) haemoglobin <10 g/dl to high probability with haemoglobin >or=13 g/dl. Cox proportional hazards regression evaluated mortality and first hospitalization among these groups.

RESULTS

The anaemia propensity score improved overall prognostic discrimination. Propensity score adjustment significantly improved prediction of mortality (P<0.0001) after covariate adjustments including haemoglobin. For mortality, the highest and lowest adjusted hazard ratios (AHR) appeared in these groups, respectively: high probability with haemoglobin <10 g/dl (AHR 1.64 [1.54, 1.75], P<0.0001), and low probability with haemoglobin 12 to <13 g/dl (AHR 0.79 [0.74, 0.85], P<0.0001). Higher haemoglobin levels were associated with lower mortality even after propensity score adjustment. Similar patterns resulted for first hospitalization; however, the interaction was significant only for hospitalization (P = 0. 0212).

CONCLUSIONS

Integrating factors predictive of anaemia improves overall prognostic discrimination. Propensity score adjustment refines the prognostic association of haemoglobin levels in haemodialysis patients.

Association between interleukin-6 and carotid atherosclerosis in hemodialysis patients

BACKGROUND

Interleukin-6 (IL-6) is associated with cardiovascular complications in general subjects. Although blood IL-6 is greatly elevated in hemodialysis (HD) patients, the role of IL-6 in the advance of atherosclerosis remains to be determined.

METHODS

We conducted a cross-sectional study to investigate the relationship between circulating IL-6 and carotid atherosclerotic changes in 156 HD patients (age 58 +/- 1 years; time on HD treatment 13 +/- 1 years; 97 males and 59 females). Serum IL-6, IgG and IgA titers of Chlamydia pneumoniae antibodies, the intima-media thickness (IMT) and the cross-sectional intima-media area (IMarea) of the carotid arteries were measured by ultrasonography in each patient.

RESULTS

Serum IL-6 levels were significantly higher in HD patients (2.04 +/- 0.16 pg/mL) compared to normal age-matched control subjects (0.31 +/- 0.06 pg/mL, N = 24). Circulating log IL-6 levels were positively correlated with IMT (r = 0.278, P < 0.01) and IMarea (r = 0.344, P < 0.01), respectively. A stepwise multiple regression analysis revealed that IL-6 became significant predictors for IMT and IMarea but not for aortic wall calcification at L2/3 vertebrae. Serum log IL-6 was significantly correlated with IgG (r = 0.277, P < 0.01) and IgA titers of anti-Chlamydia antibodies (r = 0.192, P < 0.02). Serum IgA anti-Chlamydia titers were also correlated with the maximal diameter of carotid plaque (r = 0.293, P < 0.04).

CONCLUSIONS

These findings suggested that IL-6 is associated with the severity of carotid atherosclerosis in HD patients. Persistent chronic chlamydial infection may be related, in part, to the advance of carotid plaque enlargement in dialysis patients.