In-vivo induction of monocyte chemotactic and activating factor in patients with chronic renal failure

Unexpected and striking effect of heparin-free dialysis on cytokine release

Heparin (both unfractionated and low molecular weight) is not only a potent anticoagulant but also has many pleiotropic effects, some of which are mediated by cytokine release. We compared the effect of hemodialysis (HD) with enoxaparin as an anticoagulant and without systemic anticoagulation (heparin-grafted membrane—Evodial) on the release of monocyte chemoattractant protein 1 (MCP-1), endostatin (ES) and activin A (Act-A). Nineteen stable HD patients were dialyzed with or without heparin, and plasma levels of MCP-1, ES and Act-A were measured after such a dialysis. During HD with Evodial, the intradialytic levels of all three cytokines were 2–3 folds lower. The between-anticoagulant differences were significant over time for all three cytokines: MCP-1 (P < 0.001), ES (P < 0.001) and Act-A (P < 0.001). This striking effect of heparin-free dialysis with Evodial membrane may be beneficial not only because it reduces the possibility of bleeding complications but also because it might reduce proinflammatory cytokine concentration and therefore contribute to the improvement in endothelial function. Further studies are needed to determine whether it has a positive effect on morbidity and mortality of maintenance HD patients.

The Effect of Vitamin D Administration on Intracellular Adhesion Molecule-1 and Vascular Cell Adhesion Molecule-1 Levels in Hemodialysis Patients: A Placebo-controlled, Double-blinded Clinical Trial

Objective:

Vitamin D deficiency is quite common among end-stage renal disease (ESRD) patients, and Vitamin D administration could reduce morbidity and mortality in these patients through different mechanisms. Cardiovascular diseases are the most common cause of mortality in these patients that are caused by vascular injuries. Intracellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) are vascular inflammation indicators. The goal of this study is to find the effect of Vitamin D administration on ICAM-1 and VCAM-1 serum levels in ESRD patients on hemodialysis.

Methods:

The current study is a double-blind, randomized, placebo-controlled clinical trial on 64 patients in two groups of control and treatment. Serum levels of Vitamin D, ICAM-1, and VCAM-1 were measured before and after the study. Treatment group was treated with Vitamin D pearls while control group underwent treatment with placebo pearls. Average serum levels of Vitamin D, ICAM, and VCAM were measured in both groups before and after the study and were analyzed by ANOVA, paired t-test, and Chi-square test using SPSS software.

Findings:

Sixty-four ESRD patients were recruited for this study consisting of 32 male and 32 female subjects within the ages of 18 and 76 years. The change in serum level of Vitamin D was significant in treatment group (P = 0.001) but not in control group (P > 0.05). Serum levels of ICAM and VCAM also changed significantly in treatment group (P = 0.001) but not in control group (P > 0.05)

Conclusion:

Based on the findings of this study, it could be said that Vitamin D administration in ESRD patients may increase serum level of Vitamin D up to four times. It also reduces serum levels of ICAM and VCAM which might improve the vascular condition of these patients.

Effect of magnesium sulfate and thyroxine on inflammatory markers in a rat model of hypothyroidism

Inflammation is a major risk factor for cardiovascular complications. Magnesium sulfate (MgSO4) has anti-inflammatory actions. Therefore we investigated the effects of levothyroxine and MgSO4 on inflammatory markers as C-reactive protein (CRP), interleukin-6, tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in hypothyroid rats. Sixty male rats were divided into 6 groups; normal, normal + MgSO4, hypothyroidism, hypothyroidism + levothyroxine, hypothyroidism + MgSO4, and hypothyroidism + levothyroxine + MgSO4. Thyroxine, triiodothyronine, and thyroid-stimulating hormone (TSH), CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1 were measured in all rats. Hypothyroidism significantly increased TSH, CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1 and decreased triiodothronine and thyroxine. Treatment of hypothyroid rats with levothyroxine or MgSO4 significantly decreased CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1. Combined therapy of hypothyroid rats with levothyroxine and MgSO4 significantly decreased CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1 compared with hypothyroid rats either untreated or treated with levothyroxine or MgSO4. This study demonstrates that hypothyroid rats have chronic low grade inflammation, which may account for increased risk of cardiovascular diseases. Combined levothyroxine and MgSO4 is better than levothyroxine or MgSO4 alone in alleviating the chronic low grade inflammatory status and therefore reducing the risk of cardiovascular diseases in hypothyroid animals.

NLRP3 inflammasome activation in dialyzed chronic kidney disease patients

To assess whether NLR pyrin domain-containing protein 3 (NLRP3) inflammasome, a multiprotein complex that mediates the activation of caspase-1 (CASP-1) and pro-inflammatory cytokines IL-18 and IL-1β, could be involved in the chronic inflammatory state observed in chronic kidney disease patients undergoing hemodialysis treatment (CKD-HD), we employed several biomolecular techniques including RT-PCR, western blot, FACS analysis, confocal microscopy and microarray. Interestingly, peripheral blood mononuclear cells from 15 CKD-HD patients showed higher mRNA levels of NLRP3, CASP-1, ASC, IL-1β, IL-18 and P2X7receptor compared to 15 healthy subjects. Western blotting analysis confirmed the above results. In particular, active forms of CASP-1, IL1-β and IL-18 resulted significantly up-regulated in CKD-HD versus controls. Additionally, elevated mitochondrial ROS level, colocalization of NLRP3/ASC/mitochondria in peripheral blood mononuclear cells from CKD-HD patients and down-regulation of CASP-1, IL1-β and IL-18 protein levels in immune-cells of CKD-HD patients stimulated with LPS/ATP in presence of mitoTEMPO, inhibitor of mitochondrial ROS production, suggested a possible role of this organelle in the aforementioned CKD-associated inflammasome activation. Then, microarray analysis confirmed, in an independent microarray study cohort, that NLRP3 and CASP-1, along with other inflammasome-related genes, were up-regulated in 17 CKD-HD patients and they were able to clearly discriminate these patients from 5 healthy subjects. All together these data showed, for the first time, that NLRP3 inflammasome was activated in uremic patients undergoing dialysis treatment and they suggested that this unphysiological condition could be possibly induced by mitochondrial dysfunction.

Dialysis-related transcriptomic profiling: the pivotal role of heparanase

Peritoneal (PD) and hemodialysis (HD) represent the leading renal replacement therapies in advanced chronic kidney disease (CKD). Although absolutely necessary to ensure patient survival, these treatments are responsible for considerable biological alterations primarily due to the un-physiological contact of blood and tissues with bioincompatible devices or plastificants. Although extensively described, this complex dialysis-related deregulated bio-molecular machinery is still not completely known. Therefore, to select a set of genes deregulated in patients on dialysis treatment and to assess the possible differences between dialysis modalities, we measured the expression level of 132 genes involved in proteoglycans (PGs) biosynthesis/metabolism by microarray in peripheral blood mononuclear cells (PBMCs), biological elements involved in the inflammatory/immune response, from 5 healthy subjects (HS), 9 CKD, 10 PD, and 17 HD patients. We focused on PGs biosynthesis/metabolism pathways because of their involvement in the onset and development of several CKD-related clinical complications. Statistical analysis/bioinformatics identified 70 genes discriminating HD/PD patients from HS/CKD subjects (P < 0.009, FDR < 5%). Twenty-five genes were up-regulated (e.g. HPSE, VCAN, and VEGFA) and 45 down-regulated (e.g. IDS and HEXA) in PD/HD compared to HS/CKD. Gene expression and plasma activity of Heparanase (HPSE), one of the top selected up-regulated genes in PD/HD, validated microarray results. In addition, for the second part of the study, HPSE plasmatic activities were first assessed in an independent testing-group (7 HS, 10 CKD, 17 PD, and 11 HD), and then correlated with high-sensitive C reactive protein (HS-CRP) measurements. HPSE activity was higher in PD and HD versus CKD/HS and it correlated with HS-CRP levels (R (2 )= 0.37, P = 0.007). Lipopolysaccharide (LPS)-stimulated PBMCs showed a significant up-regulation of HPSE mRNA level (P = 0.04). Our results revealed that dialysis treatments induce change in the transcriptomic pattern of biosynthetic proteoglycans in PBMCs with an up-regulation of HPSE. Our selected genes could be useful in the future as potential biomarkers and new therapeutic targets.

Oxidative stress in patients with cardiovascular disease and chronic renal failure

Oxidative response regulates many physiological response in human health, but if not properly regulated it could also lead to a number of deleterious effects. The importance of oxidative stress injury depends on the molecular target, the severity of the stress, and the mechanism by which the oxidative stress is imposed: it has been implicated in several diseases including cancer, neurodegenerative diseases, malaria, rheumatoid arthritis and cardiovascular and kidney disease. Most of the common diseases, such as hypertension, atherosclerosis, heart failure, and renal dysfunction, are associated with vascular functional and structural alterations including endothelial dysfunction, altered contractility, and vascular remodeling. Common to these processes is increased bioavailability of reactive oxygen species (ROS), decreased nitric oxide (NO) levels, and reduced antioxidant capacity. Oxidative processes are up-regulated also in patients with chronic renal failure (CRF) and seem to be a cause of elevated risk of morbidity and mortality in these patients. In this review, we highlight the role of oxidative stress in cardiovascular and renal disease.

Inflammation disrupts the LDL receptor pathway and accelerates the progression of vascular calcification in ESRD patients

Background

Chronic inflammation plays a crucial role in the progression of vascular calcification (VC). This study was designed to investigate whether the low-density lipoprotein receptor (LDLr) pathway is involved in the progression of VC in patients with end-stage renal disease (ESRD) during inflammation.

Methods and Results

Twenty-eight ESRD patients were divided into control and inflamed groups according to plasma C-reactive protein (CRP) level. Surgically removed tissues from the radial arteries of patients receiving arteriovenostomy were used in the experiments. The expression of tumour necrosis factor-α (TNF-α) and monocyte chemotactic protein-1 (MCP-1) of the radial artery were increased in the inflamed group. Hematoxylin-eosin and alizarin red S staining revealed parallel increases in foam cell formation and calcium deposit formation in continuous cross-sections of radial arteries in the inflamed group compared to the control, which were closely correlated with increased LDLr, sterol regulatory element binding protein-2 (SREBP-2), bone morphogenetic proteins-2 (BMP-2), and collagen I protein expression, as shown by immunohistochemical and immunofluorescent staining. Confocal microscopy confirmed that inflammation enhanced the translocation of the SREBP cleavage-activating protein (SCAP)/SREBP-2 complex from the endoplasmic reticulum to the Golgi, thereby activating LDLr gene transcription. Inflammation increased alkaline phosphatase protein expression and reduced α-smooth muscle actin protein expression, contributing to the conversion of the vascular smooth muscle cells in calcified vessels from the fibroblastic to the osteogenic phenotype; osteogenic cells are the main cellular components involved in VC. Further analysis showed that the inflammation-induced disruption of the LDLr pathway was significantly associated with enhanced BMP-2 and collagen I expression.

Conclusions

Inflammation accelerated the progression of VC in ESRD patients by disrupting the LDLr pathway, which may represent a novel mechanism involved in the progression of both VC and atherosclerosis.

MCP-1 and MIP3-alpha serum levels in acute liver failure and molecular adsorbent recirculating system (MARS) treatment: a pilot study

OBJECTIVE

The CC chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-3 alpha (MIP3-alpha) may be involved in the pathogenesis of acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). In ALF and ACLF, the molecular adsorbent recirculating system (MARS) has been used to support liver function. Enhancement of MCP-1, as seen in other extracorporeal support systems such as haemodialysis, might thus have mitigated the beneficial effects of the MARS system in acute hepatic failure.

MATERIAL AND METHODS

Serum concentrations of MCP-1 and MIP3-alpha were measured in 10 patients with ALF or ACLF treated with MARS. Thirteen patients suffering from chronic hepatic failure (CHF) and 15 healthy individuals served as controls.

RESULTS

Baseline MCP-1 serum concentrations were significantly increased in ALF and ACLF patients as compared to patients with CHF (p=0.0027 and p=0.0046, respectively) and controls (p=0.0006 and p=0.0012, respectively). MIP3-alpha serum concentrations were also significantly enhanced in the ALF and ACLF groups as compared with those in CHF patients (p=0.0002 and p=0.0003, respectively) and controls (p<0.0001 and p<0.0001, respectively). Moreover, MIP3-alpha levels were significantly increased in CHF patients as compared to controls (p=0.0002). MCP-1 and MIP3-alpha concentrations did not change significantly during MARS treatment in ALF and ACLF patients.

CONCLUSIONS

The CC chemokines MCP-1 and MIP3-alpha are increased in ALF and ACLF patients. MARS had no effect on MCP-1 and MIP3-alpha serum concentrations in patients with ALF and ACLF, and yielded no evidence of any harmful effects of the increase of these potentially hepatocidal chemokines.

Mitochondrial dysregulation and oxidative stress in patients with chronic kidney disease

Background

Chronic renal disease (CKD) is characterized by complex changes in cell metabolism leading to an increased production of oxygen radicals, that, in turn has been suggested to play a key role in numerous clinical complications of this pathological condition. Several reports have focused on the identification of biological elements involved in the development of systemic biochemical alterations in CKD, but this abundant literature results fragmented and not exhaustive.

Results

To better define the cellular machinery associated to this condition, we employed a high-throughput genomic approach based on a whole transcriptomic analysis associated with classical molecular methodologies. The genomic screening of peripheral blood mononuclear cells revealed that 44 genes were up-regulated in both CKD patients in conservative treatment (CKD, n = 9) and hemodialysis (HD, n = 17) compared to healthy subjects (HS, n = 8) (p < 0.001, FDR = 1%). Functional analysis demonstrated that 11/44 genes were involved in the oxidative phosphorylation system. Western blotting for COXI and COXIV, key constituents of the complex IV of oxidative phosphorylation system, performed on an independent testing-group (12 healthy subjects, 10 CKD and 14 HD) confirmed an higher synthesis of these subunits in CKD/HD patients compared to the control group. Only for COXI, the comparison between CKD and healthy subjects reached the statistical significance. However, complex IV activity was significantly reduced in CKD/HD patients compared to healthy subjects (p < 0.01). Finally, CKD/HD patients presented higher reactive oxygen species and 8-hydroxydeoxyguanosine levels compared to controls.

Conclusion

Taken together these results suggest, for the first time, that CKD/HD patients may have an impaired mitochondrial respiratory system and this condition may be both the consequence and the cause of an enhanced oxidative stress.

Down-Regulation of Intestinal Drug Transporters in Chronic Renal Failure in Rats

Chronic renal failure (CRF) is associated with an increased bioavailability of drugs by a poorly understood mechanism. One hypothesis is a reduction in the elimination of drugs by the intestine, i.e., drug elimination mediated by protein membrane transporters such as P-glycoprotein (Pgp) and multidrug-resistance-related protein (MRP) 2. The present study aimed to investigate the repercussions of CRF on intestinal transporters involved in drug absorption [organic anion-transportingpolypeptide (Oatp)] and those implicated in drug extrusion (Pgp and MRP2). Pgp, MRP2, MRP3, Oatp2, and Oatp3 protein expression and Pgp, MRP2, and Oatp3 mRNA expression were assessed in the intestine of CRF (induced by five-sixth nephrectomy) and control rats. Pgp and MRP2 activities were measured using the everted gut technique. Rat enterocytes and Caco-2 cells were incubated with sera from control and CRF rats to characterize the mechanism of transporters' down-regulation. Protein expression of Pgp, MRP2, and MRP3 were reduced by more than 40% (p < 0.01) in CRF rats, whereas Oatp2 and Oatp3 expression remained unchanged. There was no difference in the mRNA levels assessed by real-time polymerase chain reaction. Pgp and MRP2 activities were decreased by 30 and 25%, respectively, in CRF rats compared with control (p < 0.05). Uremic sera induced a reduction in protein expression and in activity of drug transporters compared with control sera. Our results demonstrate that CRF in rats is associated with a decrease in intestinal Pgp and MRP2 protein expression and function secondarily to serum uremic factors. This reduction could explain the increased bioavailability of drugs in CRF.

Role of Parathyroid Hormone in the Downregulation of Liver Cytochrome P450 in Chronic Renal Failure

Chronic renal failure (CRF) is associated with a decrease in drug metabolism secondary to a decrease in liver cytochrome P450 (P450). The predominant theory to explain this decrease is the presence of factors in the blood of uremic patients. This study tested the hypothesis that parathyroid hormone (PTH) could be this factor. The objectives of this study were to determine (1) the role of PTH in the downregulation of hepatocyte P450 induced by rat uremic serum, (2) the role of PTH in the downregulation of liver P450 in rats with CRF, and (3) the effects of PTH on P450 in hepatocytes. For this purpose, (1) hepatocytes were incubated with serum from rat with CRF that was depleted with anti-PTH antibodies or with serum from parathyroidectomized (CRF-PTX) rat with CRF, (2) the effect of PTX on liver P450 was evaluated in rats with CRF, and (3) the effects of PTH on P450 in hepatocytes were determined. The depletion of PTH from CRF serum completely reversed the downregulating effect of CRF serum on P450 in hepatocytes. Addition of PTH (10(-9) M) to depleted CRF serum induced a decrease in P450 similar to nondepleted CRF serum. The serum of CRF-PTX rats had no effect on P450 in hepatocytes compared with CRF serum. Adding PTH to CRF-PTX serum induced a similar decrease in P450 as obtained with CRF serum. Finally, PTX prevented the decrease of liver P450 in rats with CRF. In summary, PTH is the major mediator implicated in the downregulation of liver P450 in rats with CRF.

Inflammation markers, adhesion molecules, and all-cause and cardiovascular mortality in patients with ESRD: searching for the best risk marker by multivariate modeling

Inflammation is a major risk factor for mortality and cardiovascular (CV) complications in patients with ESRD. The predictive value of C-reactive protein (CRP) of the main proinflammatory cytokines (IL-1beta, IL-6, IL-18, and TNF-alpha) and of two adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) in 217 dialysis patients was compared. Serum IL-6 and CRP added significant prediction power to the multivariate Cox model of all-cause death, and the gain in the prediction power attributable to IL-6 was approximately two times higher than that of CRP. Patients in the third tertiles of serum IL-6 and CRP had a relative risk of all-cause mortality 2.5 and 1.8 times higher than those in the first corresponding tertiles, and there was no statistical difference between these two relative risks. The gain in prediction power associated with TNF-alpha, IL-beta, IL-18, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 was of small degree (P = NS). Similarly, serum IL-6 added the highest prediction power to the CV death model, and the IL-6 attributable gain was approximately two times higher than that of serum CRP. However, the risk estimate for CV mortality of patients with high serum IL-6 did not differ significantly from that of patients with high serum CRP. IL-6 adds significantly greater predictive power for all-cause and CV death to statistical models based on traditional and nontraditional risk factors in ESRD patients. However, the risk estimate by CRP being reasonably close to that of IL-6, CRP may be a cheap alternative to IL-6 in clinical practice.

Effects of renal diseases on the regulation and expression of renal and hepatic drug-metabolizing enzymes: a review

1. The activity of drug-metabolizing enzymes (DMEs) in extrahepatic organs is highest in the kidneys. Generally, the kidneys contain most, if not all, of the DMEs found in the liver. Surprisingly, some of these DMEs show higher activity in the kidneys than in the liver. 2. Most of the renal DMEs are localized in the cortex of the kidneys, especially in the proximal tubules. DMEs are also found in the distal tubules and collecting ducts. 3. Renal diseases such as acute and chronic renal failure and renal cell carcinoma alter the regulation of both hepatic and extrahepatic phase I and II DMEs. Changes in the expression of these DMEs seem to be tissue and species specific. 4. Generally, there is significant down-regulation of most of the phase I and a few of phase II DMEs at the protein, mRNA and activity levels. Unfortunately, the mechanisms leading to the alteration in DMEs in renal diseases remain unclear, although many theories have been made. 5. The presence of some circulating factors such as cytokines, nitric oxide, parathyroid hormones and increased intracellular calcium play a role in the regulation of DMEs in renal diseases.

Down-regulation of hepatic cytochrome p450 in chronic renal failure: role of uremic mediators

1. Chronic renal failure (CRF) is associated with a decrease in liver cytochrome p450 (p450). The mechanism remains poorly understood. The present study aimed to investigate the effects of the serum of rats with CRF on liver p450. 2. Normal rat hepatocytes were incubated for 24 h with serum (concentration of 10%) from rats with CRF and from control animals in order to measure (1). total p450 level, (2). protein expression and mRNA levels of major p450 isoforms, and (3). some of their specific metabolic activities (N-demethylation of erythromycin). Time-course experiments (incubation time from 12 to 48 h) and dose-response curves (concentration of serum ranging from 1 to 30%) have been conducted. 3. In normal hepatocytes incubated for 24 h with serum (concentration of 10%) from rats with CRF, total p450 level, protein expression and mRNA levels of several p450 isoforms (CYP2C6, 2C11, 3A1 and 3A2) were decreased by more than 35% (P<0.001) compared to serum from control animals. The protein expression as well as the mRNA levels of CYP2D were similar in hepatocytes incubated with serum from either control or CRF rats. The N-demethylation of erythromycin was decreased by more than 35% (P<0.001) in hepatocytes incubated with serum from rats with CRF. The inhibitory effect of serum from rats with CRF tended to peak at 48 h of incubation and was maximum at a concentration of 20%. 4. In conclusion, uremic serum contains mediator(s) that down-regulate the cytochrome p450 of normal hepatocytes secondary to reduced gene expression.

Circulating levels of ICAM-1, VCAM-1, and MCP-1 are increased in haemodialysis patients: association with inflammation, dyslipidaemia, and vascular events

BACKGROUND

Increased levels of circulating adhesion molecules and chemokines have been reported in haemodialysis (HD) patients but the influence of the HD membranes on their secretion, as well as their pathophysiological implications, remains largely unknown.

METHODS

Circulating levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1) were measured by immunosorbent assay (ELISA) in 81 HD patients (45 male, mean age 57+/-13 years) and 35 normal subjects. All patients had been stabilized on renal replacement therapy for >3 months and were free of active infection. Thirty-three patients (40.7%) were routinely dialysed with modified cellulose membranes and 48 patients (59.3%) were dialysed with polysulfone membranes. Blood samples were taken directly from the arteriovenous fistula immediately before and at the end of a routine HD session.

RESULTS

Pre-dialysis levels were significantly elevated in HD patients compared with controls (ICAM-1 515+/-177 vs 238+/-664 ng/ml, P<0.0001; VCAM-1 2107+/-648 vs 1012+/-115 ng/ml, P<0.0001; MCP-1 427+/-148 vs 125+/-42 pg/ml, P<0.0001). The HD session resulted in a significant increase in the levels of all three molecules measured (515+/-177 vs 679+/-187 ng/ml, P<0.0001; 2107+/-648 vs 2662+/-800 ng/ml, P<0.0001; 427+/-148 vs 567+/-153 pg/ml, P<0.0001, respectively). There was no difference in pre- or post-dialysis levels of the above molecules between patients routinely dialysed with either modified cellulose or polysulfone membranes. MCP-1 levels had a positive correlation with ICAM-1 levels (r=0.41, P<0.0005). VCAM-1 levels had a negative correlation with HDL levels (r=-0.30, P<0.01) and were significantly elevated in patients with HDL <35 mg/dl compared with patients with HDL > or = 35 mg/dl (2300+/-606 vs 1890+/-633 ng/ml, P<0.005). Log-transformed exact C-reactive protein (CRP) values were significantly correlated with ICAM-1 and VCAM-1 levels (r=0.41, P<0.005 and r=0.43, P<0.005, respectively). In addition, compared with patients with normal CRP values, patients with elevated CRP had significantly increased levels of ICAM-1 (466+/-166 vs 580+/-172 ng/ml, P<0.005). Patients with cardiovascular, cerebrovascular, or peripheral vascular diseases had significantly increased serum CRP and ICAM-1 levels compared with patients with no evidence of vascular disease (19.2+/-12.9 vs 7.9+/-11.8 mg/l, P<0.001 and 608+/-189 vs 474+/-155 ng/ml, P<0.005 respectively).

CONCLUSIONS

Serum levels of ICAM-1, VCAM-1, and MCP-1 are increased in HD patients and probably result from either inadequate clearance or enhanced synthesis and release. HD session resulted in a significant increase of the above molecule levels but the exact mechanism(s) responsible for these alterations are yet to be fully elucidated. Increased levels of adhesion molecules are associated with inflammation, dyslipidaemia, and cardiovascular events. However, the potential link between these processes and its clinical significance warrants further investigation.

Three monocyte-related determinants of atherosclerosis in haemodialysis

BACKGROUND

It has been suggested that monocyte-related inflammatory mediators play a role in atherosclerosis. Haemodialysis induces phenotypic changes in adhesion molecule expression on monocytes. Soluble vascular cell adhesion molecule-1 (sVCAM-1), an adhesion molecule involved in monocyte recruitment, has been proposed to correlate with the extent of atherosclerosis in humans. Monocyte chemotactic protein-1 (MCP-1) functions as a monocyte-specific chemoattractant.

METHODS

We studied monocyte count, CD11b/CD18 expression on monocytes, MCP-1, and sVCAM-1 in nine patients on either cuprophane or polysulphone haemodialysis (n=18 treatments) at times 0 (before haemodialysis), 3 h (end of haemodialysis), 4, 6, 8 and 24 h after start of treatment, as well as in 18 healthy subjects.

RESULTS

Monocyte CD11b/CD18 expression increased with both membranes (P:<0.001) during and after dialysis compared to before treatment. The concentrations of sVCAM-1 and MCP-1 were higher in patients compared to those in controls both before, during and after haemodialysis (P:<0.001 at all time points). There were correlations between the expression of CD11b/CD18 on monocytes and the interdialytic concentrations of sVCAM-1 (r=0.76, P:<0.001) and MCP-1 (r=0.54, P:<0.05) and between MCP-1 and sVCAM-1 before and after haemodialysis (P:<0.05).

CONCLUSION

Patients on haemodialysis have an increased systemic chemotactic activity for monocytes, unphysiological phenotypic alterations in CD11b/ CD18 expression during and after dialysis, and increased sVCAM-1 and MCP-1 concentrations. Prospective studies are needed to establish the role of these abnormalities in the pathogenesis of atherosclerosis in haemodialysis patients.

Impaired monocyte CD11b expression in interstitial inflammation in hemodialysis patients

BACKGROUND

It is not known to what extent intravascular phenotypic alterations in adhesion molecule expression induced by hemodialysis influence the recruitment of monocytes and their ability to up-regulate CD11b at the local site of inflammation in the interstitium. Using a skin suction chamber technique, we addressed these issues in eight hemodialysis patients and in eight healthy subjects.

METHODS

Two skin blisters were raised on the forearm of each individual and blister exudate collected. The blisters were then stimulated with autologous serum (active blister, intense inflammation) or buffer (control blister, intermediate inflammation), respectively. Thereafter the patients were treated with Cuprophan hemodialysis for four hours. After 10 hours, the exudate was aspirated from each chamber in all subjects. Monocyte count and expression of CD11b were analyzed in serum and blister fluid by flow cytometry. Then, monocytes from healthy blood donors were incubated in blister fluid from patients and healthy subjects in order to determine the local chemotactic activity in terms of CD11b up-regulation. Monocyte chemotactic protein-1 (MCP-1), a marker of systemic monocyte chemotactic activity, was also analyzed in serum at 0 and 10 hours in all individuals.

RESULTS

The number of monocytes at the site of inflammation in the interstitium in hemodialysis patients correlated with the expression of CD11b on transmigrated cells (r = 0.78, P < 0.001). Monocytes collected in the active blister fluid of dialysis patients expressed equal levels of CD11b as cells collected from healthy subjects. By contrast, monocytes collected from the control blisters of patients expressed lower levels of CD11b than cells from healthy subjects (P < 0.01), despite equal interstitial biological activity of CD11b-mobilizing factors in blister fluid from patients and healthy subjects and the fact that patients had higher systemic chemotactic activity in terms of MCP-1 concentration in serum (P < 0.001).

CONCLUSION

Monocytes from hemodialysis patients have the capacity to mobilize CD11b to the same extent as cells from healthy individuals at the inflammatory spot, but more intense stimuli are required for such actions, probably because of a transient refractoriness.

Serum concentrations and peripheral secretion of the beta chemokines monocyte chemoattractant protein 1 and macrophage inflammatory protein 1alpha in alcoholic liver disease

BACKGROUND

Alcoholic liver disease is associated with increased hepatic expression of monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1alpha (MIP-1alpha).

AIMS

To determine whether concentrations of chemokines in the peripheral circulation reflect disease activity, and whether chemokine secretion is restricted to the liver or is part of a systemic inflammatory response in alcoholic liver disease.

PATIENTS

Fifty one patients with alcoholic liver disease and 12 healthy controls.

METHODS

Peripheral vein (and hepatic vein in patients undergoing transjugular liver biopsy) chemokine concentrations were measured by ELISA. Chemokine secretion and transcription in isolated peripheral mononuclear cells were assessed using ELISA and in situ hybridisation in patients with severe alcoholic hepatitis.

RESULTS

Serum MCP-1 concentrations were higher in alcoholic hepatitis compared with cirrhosis or healthy controls. MIP-1alpha concentrations were below the assay sensitivity in most patients. Serum MCP-1 concentrations correlated significantly with serum aspartate aminotransferase and creatinine. In severe alcoholic hepatitis, MCP-1 concentrations were higher in hepatic compared with peripheral veins; in mild alcoholic hepatitis there was no difference. Mononuclear cell secretion of both MCP-1 and MIP-1alpha was higher in severe alcoholic hepatitis compared with healthy controls, and chemokine mRNA was identified in monocytes.

CONCLUSIONS

Serum MCP-1 concentrations are raised in alcoholic liver disease and reflect severity of hepatic inflammation. Monocyte secretion of both MCP-1 and MIP-1alpha is increased in severe alcoholic hepatitis. Both intrahepatic sources and peripheral mononuclear cells contribute to the raised serum MCP-1 concentrations.

Interleukin-6, interleukin-8 and monocyte chemotactic peptide-1 gene expression and protein synthesis are independently modulated by hemodialysis membranes

BACKGROUND

Uremia produces a wide range of abnormalities of the immune system. Blood-membrane interaction in hemodialysis results in activation and severe dysfunction of peripheral blood mononuclear cells (PBMC). However, the question of whether the use of different dialytic membranes may improve PBMC dysfunctions remains unanswered.

METHODS

To address this issue, the spontaneous interleukin (IL)-6, IL-8 and monocyte chemotactic peptide-1 (MCP-1) gene expression and protein release were studied in PBMC isolated from 7 healthy subjects, 8 uremic patients on conservative therapy and 8 uremic patients undergoing subsequent one month periods of hemodialysis with cuprophan (CU) and high-flux noncomplement activating membranes, polymethylmethacrylate (PMMA) and polyamide (PA). At the end of each period of treatment, PBMC were harvested at the beginning (T0) and after 180 minutes of dialysis (T180), and then were cultured in complete medium. IL-6, IL-8 and MCP-1 mRNA expression were studied by RT-PCR. In addition, MCP-1 gene expression was evaluated also by in situ hybridization. Cytokines released in the supernatant were measured by ELISA.

RESULTS

Compared to the control group, PBMC from uremic patients on conservative therapy and treated by CU showed a clear reduction in the cytokine release, while PMMA and PA membranes were able to normalize IL-6, IL-8 and MCP-1 protein concentration, which had been reduced by CU treatment. Interestingly, at T0, mRNA expression for all three cytokines was increased in the patients treated by CU, when compared to the control group and the uremic patients on conservative therapy. A further up-regulation was observed at T180. PMMA and PA treatment, despite increasing the cytokine secretion, significantly reduced the dialysis-induced cytokine gene expression.

CONCLUSION

PBMC exposure to CU membranes results in cytokine mRNA overexpression associated with a paradoxically reduced protein release. In contrast, long-term hemodialysis with synthetic high-flux membranes reduces IL-6, IL-8 and MCP-1 gene expression and improves the ability of PBMC to secrete these cytokines. The reduced cytokine secretion during bioincompatible dialysis may reflect a PBMC adaptation that protects uremic patients against the inflammatory effects of persistent cytokine release.