Renoprotective effect of erythropoietin in rats subjected to ischemia/reperfusion injury: gender differences

BACKGROUND

Renal ischemia reperfusion injury induces gender-dependent heat-shock protein 72 expression, which maintains membrane localization of renal Na(+)/K(+)ATPase-α1. The erythropoietin has a protecting effect against ischemia reperfusion injury in various organs. In this study, we investigated whether erythropoietin exerts a beneficial effect against post-ischemic renal injury. Furthermore, we studied the erythropoietin signaling on heat-shock protein 72 and Na(+)/K(+)ATPase-α1 expression and localization.

METHODS

In male and female Wistar rats, rHuEPO (1000 IU/bwkg intraperitoneal) or vehicle was administered 24 hours prior to unilateral left renal ischemia reperfusion (50 minutes). Kidneys were subsequently removed at hours 2 or 24 of the reperfusion; sham-operated rats served as controls (C) (n = 8/group). We measured serum erythropoietin, renal function, evaluated histological injury, and observed heat-shock protein 72 as well as Na(+)/K(+)ATPase-α1 protein level and localization. Additional groups were followed for 7-day survival.

RESULTS

Erythropoietin treatment was associated with better post-ischemic survival and less impaired renal function in males while diminishing the renal structural damage in both sexes. Endogenous erythropoietin was higher in males and increased in both genders after erythropoietin treatment. The erythropoietin treatment elevated protein levels of heat-shock protein 72 and Na(+)/K(+)ATPase-α1 in 24 hours in males, whereas in females, the already higher expression of heat-shock protein 72 and Na(+)/K(+)ATPase-α1 was not increased. Moreover, erythropoietin prevented ischemia reperfusion induced Na(+)/K(+)ATPase-α1 translocation from the basolaterale membrane in males.

CONCLUSION

Erythropoietin diminishes gender difference in the susceptibility to renal post-ischemic injury and reduces post-ischemic structural damage while preserving kidney function, particularly in males. This additional protection may be associated with a heat-shock protein 72-mediated effect on Na(+)/K(+)ATPase-α1 expression and translocation.

ARFI-based tissue elasticity quantification in comparison to histology for the diagnosis of renal transplant fibrosis

BACKGROUND AND PURPOSE

Until recently clinical diagnosis of chronic renal allograft dysfunction could only be established invasively by renal biopsy. Given the risks of that procedure, a non-invasive, diagnostic test would be very advantageous. Novel ultrasound-based elasticity tools, using "Acoustic Radiation Force Impulse (ARFI)" technology are now available. Previously this technique has been utilised to quantify liver fibrosis. First results of these studies are promising. The purpose of our study was to investigate correlation between stiffness values obtained by ARFI-quantification and histological fibrosis score in renal transplants.

METHODS

We employed "Virtual Touch™ tissue quantification" (Siemens Acuson, S2000) to quantitatively measure tissue stiffness in the cortex of transplant kidneys. Eighteen patients were included in this prospective study, recording close temporal ARFI-quantification and fibrosis measurements. All patients undergoing renal transplant biopsy were examined with ARFI-quantification (15 measurements per transplant kidney). Resistive indices were also calculated from pulsed-wave Doppler ultrasound. Transplant biopsies were histologically evaluated by a reference nephropathologist and graded according to the percentage of fibrosis and to the BANFF-score. Due to the non-normal distribution of the data the Spearman-correlation-coefficient (rho) was used to assess the bivariate relationship of ARFI and fibrosis in the transplant kidney.

RESULTS

There was a significant positive moderate correlation between mean ARFI-values and the grade of fibrosis (rho = +0.465; p = 0.026). This correlation was also valid for the mean ARFI-values and the BANFF-category (rho = +0.468; p = 0.025). There was no significant correlation between the mean ARFI-values and the resistive indices in the transplant kidney (rho = +0.034; p = 0.904). Nevertheless, a positive correlation between the mean RI-values of the kidney and the grade of fibrosis was established (rho = +0.563; p = 0.015).

CONCLUSION

The mean values of ARFI measurements and the resistive indices are potentially independent explanation variables for evaluating the grade of fibrosis in transplant kidneys.

MEIS1 and BTBD9: genetic association with restless leg syndrome in end stage renal disease

Background

Restless legs syndrome (RLS) is a sleep related movement disorder that occurs both in an idiopathic form and in symptomatic varieties. RLS is a frequent and distressing comorbidity in end stage renal disease (ESRD). For idiopathic RLS (iRLS), genetic risk factors have been identified, but their role in RLS in ESRD has not been investigated yet. Therefore, a case–control association study of these variants in ESRD patients was performed.

Methods

The study genotyped 10 iRLS associated variants at four loci encompassing the genes MEIS1, BTBD9, MAP2K5/SKOR1, and PTPRD, in two independent case–control samples from Germany and Greece using multiplex PCR and MALDI-TOF (matrix assisted laser desorption/ionisation time-of-flight) mass spectrometry. Statistical analysis was performed as logistic regression with age and gender as covariates. For the combined analysis a Cochran–Mantel–Haenszel test was applied.

Results

The study included 200 RLS-positive and 443 RLS-negative ESRD patients in the German sample, and 141 and 393 patients, respectively, in the Greek sample. In the German sample, variants in MEIS1 and BTBD9 were associated with RLS in ESRD (P_nom≤0.004, ORs 1.52 and 1.55), whereas, in the Greek sample, there was a trend for association to MAP2K5/SKOR1 and BTBD9 (P_nom≤0.08, ORs 1.41 and 1.33). In the combined analysis including all samples, BTBD9 was associated after correction for multiple testing (P_corrected=0.0013, OR 1.47).

Conclusions

This is the first demonstration of a genetic influence on RLS in ESRD patients with BTBD9 being significantly associated. The extent of the genetic predisposition could vary between different subgroups of RLS in ESRD.

Endorsement of the Kidney Disease Improving Global Outcomes (KDIGO) guidelines on kidney transplantation: a European Renal Best Practice (ERBP) position statement

KDIGO (Kidney Disease: Improving Global Outcomes) is an international independent body aiming to 'improve the care and outcomes of kidney disease patients worldwide, through the development and implementation of clinical practice guidelines'. Recently, the KDIGO work group has produced comprehensive clinical practice guidelines for the care of kidney transplant recipients (KTRs). The guideline makes recommendations for immunosuppression, graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy and other complications that are common in KTRs, including haematological and bone disorders. Because most guidelines were 'soft' rather than 'strong', and because global guidelines need to be adapted and implemented into the regional context where they are used, the European Renal Best Practice (ERBP) Advisory Board appointed a work group of transplant nephrologists and surgeons to review the newest KDIGO guideline and comment on its relevance and applicability for European KTRs. In this article, we concentrate only on those guidelines which we considered worth amending or adapting. All guidelines not mentioned are fully endorsed.

STAT1-mediated signal integration between IFNγ and LPS leads to increased EC and SMC activation and monocyte adhesion

Inflammation plays an important role in host defenses against infectious agents and injury, but it also contributes to the pathophysiology of atherosclerosis. Signal transducer and activated transcription 1 (STAT1) has been identified as a point of convergence for the cross talk between the pro-inflammatory cytokine interferon γ (IFNγ) and the Toll-like receptor-4 (TLR4) ligand LPS in immune cells. However, there is no information available on the role of STAT1 in TLR4-mediated progression of atherosclerosis and on potential synergism between lipopolysaccharides (LPS) and IFNγ signaling in cells from the vasculature. Cultured human microvascular endothelial cells (HMECs) exposed to LPS activated STAT1 in a delayed manner that was inhibited by cycloheximide treatment. Pretreatment of HMECs as well as primary vascular smooth muscle cells (VSMCs) with IFNγ followed by LPS resulted in a significant increase in STAT1 phosphorylation compared with both factors alone. Increased STAT1 protein levels, strictly mediated by IFNγ, correlated with the augmented STAT1 phosphorylation that was absent in TLR4(-/-) cells. As assessed by PCR, Western analysis, and ELISA, this coincided with increased expression of the chemokine interferon gamma-induced protein 10 kDa (IP-10) and the adhesion molecule ICAM-1 in a TLR4-dependent manner.The STAT1-inhibitor fludarabine markedly reduced these effects as well as IFNγ and LPS-dependent adhesion of U937 cells to endothelial cells, emphasizing the potential importance of STAT1 in the integration of both signals. With the established roles of IFNγ and TLRs in atherosclerotic pathology, the STAT1-dependent signal integration between IFNγ and TLR in ECs and VSMCs in response to exogenous and endogenous atherogenic ligands could result in amplification of pro-inflammatory responses in the damaged vessel and be a novel mechanism involved in the initiation and progression of atherosclerosis.

High dose human insulin and insulin glargine promote T24 bladder cancer cell proliferation via PI3K-independent activation of Akt

BACKGROUND

This study was to investigate the effects of human insulin and insulin glargine on proliferation of T24 human bladder cancer cells and the implication of the PI3K/Akt and MEK/ERK1/2 pathways.

METHODS

After exposure to insulin or glargine at the indicated concentrations for certain time courses, in the absence or presence of inhibitor for MEK (PD98059) or PI3K (LY294002), T24 cell proliferation was evaluated by CCK-8 assay. Phosphorylation of Akt and ERK1/2 was analyzed by Western blot.

RESULTS

Insulin and glargine similarly induced phosphorylation of Akt and slight increases in T24 cell proliferation at 10-100IU/L. LY294002 remarkably reduced T24 cell proliferation in all groups. However, in the presence of LY294002, cell growth was still promoted by insulin and glargine relative to LY294002-treated group. Accordingly, LY294002 profoundly reduced protein levels of pAkt, while insulin and glargine increased pAkt in T24 cells pretreated with LY294002 as compared with cells treated with LY294002 alone. PD98059 reduced pERK while enhanced T24 cell proliferation. Insulin and glargine increased pERK at 15, 30, 60 min, not at 24h.

CONCLUSIONS

High dose human insulin and insulin glargine similarly promoted T24 bladder cancer cell proliferation via PI3K-independent activation of Akt.

Donor antigen-specific regulatory T-cell function affects outcome in kidney transplant recipients

Chronic transplant dysfunction, a major impediment to long-term allograft survival, is caused by several factors including an ongoing alloimmune response termed chronic rejection. To define some of these factors further, we selected 107 patients mismatched to their donors from 623 patients transplanted at a single center. Patients were categorized according to their immunosuppressive treatment and further divided into those with stable or chronic allograft dysfunction. Donor human lymphocyte antigen allopeptide-specific T-cell lines were then generated from stable patients and those with biopsy-proven chronic allograft nephropathy. Increased amounts of CD4+CD25+ regulatory T cells (Tregs) and Treg-associated gene expression profiles were found in cell lines derived from the patients with stable compared with those with chronic allograft dysfunction. Furthermore, a higher percentage of Tregs was found in patients with stable graft function on tacrolimus-based compared with cyclosporine-based immunosuppression protocols. Patients with stable graft function had a significantly higher expression of interleukin (IL)-4 and IL-10, whereas the cytokines IL-2, IL-17, and interferon-γ were significantly higher in patients with allograft dysfunction in vitro. Thus, enhancing the operational role of naturally occurring donor-specific Tregs in allograft recipients by adjusting the immunosuppression protocol may be advantageous particularly for patients with ongoing chronic rejection.

If the knee hurts, don't forget the spine!

Calcium pyrophosphate dihydrate crystal-deposits (CPPD) at the spine are rare but the lesions detected with CT scans or MRI are often interpreted as a spondylodiscitis or osteitis. CPPD is a disease of the elderly without major sex predominance. The diagnosis of CPPD requires typical manifestations on a radiograph and/or detection of positively birefringent crystals in the synovial fluid of (peripheral) joints by compensated polarized light microscopy. CPPD crystal deposition at the spine has been associated with clinical manifestations, typically spine stiffness, and is sometimes associated with bony ankylosis or diffuse idiopathic skeletal hyperostosis. The preferred treatment of CPPD in the acute phase is oral non-steroidal anti-inflammatory medication or alternatively oral or intravenous glucocorticoids. CPPD should be considered in patients with non-specific spinal lesions.

Associations of fetuin-A levels with vascular disease in type 2 diabetes patients with early diabetic nephropathy

Background

Ambigous results exist on fetuin-A as marker for vascular disease in type 2 diabetes. This study aims to define the role of fetuin-A as marker for micro- and macrovascular disease in a high risk population of patients with type 2 diabetes mellitus and early diabetic nephropathy.

Methods

Fetuin-A serum levels were assessed by ELISA in a cross-sectional setting in 153 patients with type 2 diabetes. Associations of fetuin-A with metabolic, inflammatory and vascular markers were studied. Atherosclerotic burden was assessed by ankle-brachial-index (ABI) as well as detection of common carotid artery intima-media thickness (IMT).

Results

Levels of fetuin-A were lower in male than in female patients (0.49 ± 0.15 vs. 0.56 ± 0.20 g/L, p = 0.02). In addition, there was an inverse correlation with age (r = -0.20, P = 0.01). Bivariate correlations adjusted for age and gender revealed no significant correlations with metabolic parameters, except for a weak inverse correlation with serum adiponectin (r = -0.19, p = 0.02). Regarding parameters of micro- and macrovascular disease, fetuin-A was significantly associated with ABI (r = 0.18, p = 0.04), while there was no association with IMT (r = -0.07, p = n.s). Patients with an ABI < 0.9 had lower fetuin A levels than patients with an ABI 0.9-1.3 or > 1.3 (0.43 ± 0.10 vs. 0.52 ± 0.17 vs. 0.54 ± 0.18 g/L p = 0.05). Neither GFR nor albuminuria were associated with fetuin-A serum levels. Patients with prevalent neuropathy did not have altered fetuin-A levels compared to diabetic controls. In step-wise logistic regression analysis including age, gender, HbA1c, total cholesterol, glomerular filtration rate and fetuin-A, only total cholesterol (β = 0.01, p = 0.02) and fetuin-A (β = -5.99, p = 0.03) proved to be independent predictors of an ABI < 0.9.

Conclusions

The results of this cross-sectional study suggest that lower fetuin-A levels are associated with macrovascular late complications in high-risk type 2 diabetes patients while there are no associations of fetuin-A with metabolic status or microvascular complications.

Toll-like receptor (TLR) 7 and TLR8 expression on CD133+ cells in colorectal cancer points to a specific role for inflammation-induced TLRs in tumourigenesis and tumour progression

Toll-like receptor (TLR) stimulation results in activation of NF-κB, a key modulator in driving inflammation to cancer and mitogen-activated protein kinases that have been shown to recruit mitotic and cyclooxygenase-2 (COX-2) induced pathways in carcinogenesis. Here we asked whether different TLR, COX-2 and stem cell marker expression profiles in colorectal cancer (CRC) provide further evidence for this hypothesis from a clinical perspective. We analysed gene and protein expression of TLR7-TLR10, COX-2 and CD133 as a marker for colon-initiating cells in CRC patients (n=65). Gene analysis demonstrated significantly upregulated TLR7-TLR10 and COX-2 expression in CRC tumour tissues. Analysis of isolated tumour cells from primary tumours showed co-expression of TLR7 and TLR8 with CD133 and gave evidence for a subpopulation of colon cancer-initiating cells. In multivariate analyses TLR8 expression was found to be an independent prognostic factor. Persistent TLR-specific activation of NF-κB in CRC and particularly in tumour-initiating cells may thus sustain further tumour growth and progression through perpetuated signalling known from inflammatory and tissue repair mechanisms with consecutive self-renewal in pluripotent tumour cells. Activation through self-ligands or viral RNA fragments may putatively maintain this inflammatory process, suggesting a key role in cancer progression.

TRAF6 knockdown promotes survival and inhibits inflammatory response to lipopolysaccharides in rat primary renal proximal tubule cells

AIM

TRAF6 is a unique adaptor protein of the tumour necrosis factor receptor-associated factor family that mediates both tumour necrosis factor receptor (TNFR) and interleukin-1 receptor/Toll-like receptor (IL-1R/TLR) signalling. Activation of IL-1R/TLR and TNFR pathways in renal tubular cells contributes to renal injury. This study aimed to investigate if blockade of lipopolysaccharide (LPS)-triggered TLR4 signalling by small interfering RNA (siRNA) targeting TRAF6 protects survival and inhibits inflammatory response in isolated rat renal proximal tubular cells (PTCs).

METHODS

PTCs isolated from F344 rat kidneys were transfected with chemically synthesized siRNA targeting TRAF6 mRNA. Real-time quantitative PCR was applied to measure mRNA level of TRAF6, TNF-alpha, IL-6 and monocyte chemoattractant protein-1 (MCP-1). Protein levels of extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase, caspase 3 and cleaved caspase 3 were evaluated by Western blotting. Cell viability was analysed with XTT reagents.

RESULTS

We found that the TRAF6 gene was effectively silenced in PTCs using siRNA. TRAF6 knockdown resulted in reduced TNF-alpha and IL-6 mRNA expression upon LPS challenge. LPS-induced phosphorylation of JNK and p38 was attenuated in TRAF6 siRNA-transfected cells while the change in the phosphorylation of ERK was not remarkable. TRAF6 knockdown was associated with increased cell viability and reduced protein level of cleaved caspase-3, both, in the absence and presence of LPS.

CONCLUSION

Our studies suggest that TRAF6 knockdown may inhibit inflammatory response and promote cell survival upon LPS challenge in primary rat proximal renal tubular cells.

Serum fetuin-A, cardiovascular risk factors, and six-year follow-up outcome in patients with coronary heart disease

High circulating fetuin-A has recently been linked to risk of primary cardiovascular disease (CVD). The clinical importance of fetuin-A in patients at markedly increased cardiovascular risk, however, has not been fully elucidated. We studied the association between serum fetuin-A and future cardiovascular outcome in patients with prevalent coronary heart disease (CHD). Fetuin-A levels were measured in 1,049 patients with CHD. Associations with traditional cardiovascular risk factors and with secondary CVD events during 6 years of follow-up (median 73.4 months, interquartile range 57.4 to 74.3) were analyzed. Serum fetuin-A levels were significantly increased in patients with prevalent hypertriglyceridemia (0.71 vs 0.69 g/L, p = 0.013). No association with baseline metabolic syndrome was found (odds ratio 0.95 for highest vs lowest fetuin-A quintile, 95% confidence interval 0.59 to 1.53, p = 0.82). In Cox proportional hazards analyses, serum fetuin-A levels were not significantly associated with secondary CVD events (hazard ratio 0.67 for highest vs lowest fetuin-A quintile, 95% confidence interval 0.37 to 1.21, p = 0.18). In conclusion, fetuin-A is significantly associated hypertriglyceridemia but not with other traditional cardiovascular risk factors or metabolic syndrome in patients with manifest CHD. Measurement of serum fetuin-A levels may not emerge as a valuable tool for evaluating future CVD risk in patients aggressively treated for advanced atherosclerosis.

Anti-inflammatory treatment strategies for ischemia/reperfusion injury in transplantation

Inflammatory reactions in the graft have a pivotal influence on acute as well as long-term graft function. The main reasons for an inflammatory reaction of the graft tissue are rejection episodes, infections as well as ischemia/reperfusion (I/R) injury. The latter is of particular interest as it affects every solid organ during the process of transplantation. I/R injury impairs acute as well as long-term graft function and is associated with an increased number of acute rejection episodes that again affect long-term graft outcome.

I/R injury is the result of ATP depletion during prolonged hypoxia. Further tissue damage results from the reperfusion of the tissue after the ischemic insult. Adaptive cellular responses activate the innate immune system with its Toll-like receptors and the complement system as well as the adaptive immune system. This results in a profound inflammatory tissue reaction with immune cells infiltrating the tissue. The damage is mediated by various cytokines, chemokines, adhesion molecules, and compounds of the extracellular matrix. The expression of these factors is regulated by specific transcription factors with NF-κB being one of the key modulators of inflammation.

Strategies to prevent or treat I/R injury include blockade of cytokines/chemokines, adhesion molecules, NF-κB, specific MAP kinases, metalloproteinases, induction of protective genes, and modulation of the innate immune system. Furthermore, preconditioning of the donor is an area of intense research. Here pharmacological treatment as well as new additives to conventional cold storage solutions have been analyzed together with new techniques for the perfusion of grafts, or methods of normothermic storage that would avoid the problem of cold damage and graft ischemia.

However, the number of clinical trials in the field of I/R injury is limited as compared to the large body of experimental knowledge that accumulated during recent years in the field of I/R injury. Future activities in the treatment of I/R injury should focus on the translation of experimental protocols into clinical trials in order to reduce I/R injury and, thus, improve short- as well as long-term graft outcome.

Treatment of relapsing polychondritis with the TNF-alpha antagonist adalimumab

Relapsing polychondritis (RP) is a rare immune-mediated disease which is associated with inflammation in cartilaginous tissue throughout the body. Especially, the cartilaginous structures of ear, respiratory tract, nose, and joints are affected. Around 30% of the cases are associated with other diseases especially systemic vasculitis. Onset of RP is most likely between the ages of 40-60 years. This case reports the often disguised and similar symptoms of RP to Wegner's granulomatosis and the challenge of diagnosis. The relative rarity of RP has not permitted clinical trials to determine the efficacy and safety of different therapies. Current treatment is largely empiric and based on case reports. In this case, we successfully used a treatment with the TNF-alpha antagonist adalimumab.

Effect of experimental hyperglycaemia on renal haemodynamics in prediabetic patients with and without AT1 receptor blockade

BACKGROUND AND OBJECTIVES

To prevent diabetic nephropathy, knowledge about early renal impairment caused by a disturbed glucose homoeostasis is essential. The purpose of our study was to investigate haemodynamic changes of the kidney in subjects with impaired glucose tolerance (prediabetics, IGT) during experimental hyperglycaemia and the effect of angiotensin receptor blockade.

DESIGN

In our prospective case control study, we measured renal haemodynamics in 13 non-albuminuric males with normal kidney function and IGT (diagnosed by an oral glucose tolerance test, OGTT) and in 13 matched controls with a normoglycemic response in the OGTT. Glomerular filtration rate (GFR) was assessed by determination of sinistrin clearance; renal plasma flow (RPF) by para-aminohippuric acid clearance. All measurements were performed at rest and during hyperglycaemic stress testing (clamp technique; target blood glucose approximately 170 mg dL(-1)). We examined renal effects of valsartan (4 weeks 160 mg day(-1)) at rest and during experimental hyperglycaemia. Metabolic (glycosylated haemoglobin, adiponectin) and inflammatory (high sensitive C-reactive protein) parameters were compared with and without valsartan in both groups.

RESULTS

During experimental hyperglycaemia, GFR and RPF decreased significantly more in prediabetics compared with controls. Under valsartan, the hyperglycaemia induced decrease of GFR and RPF was blunted in part by valsartan. Hs-CRP and HbA1c were significantly higher in prediabetics when compared with controls and improved both under valsartan. Adiponectin was lower in prediabetics and increased significantly under valsartan.

CONCLUSIONS

Hyperglycaemia induces impairments of renal haemodynamics as well as inflammatory and metabolic parameters in subjects with impaired glucose tolerance, which improve under valsartan.

Effect of Renin-Angiotensin system blockade on insulin resistance and inflammatory parameters in patients with impaired glucose tolerance

OBJECTIVE

The study investigated the effect of angiotensin receptor blockers (ARB) on glucose homeostasis and inflammatory parameters in patients with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

We prospectively studied the insulin sensitivity index (ISI) and homeostasis model assessment-insulin resistance (HOMA-IR) in 13 obese males with IGT and in 13 matched control subjects with normal glucose tolerance (NGT) during hyperglycemic testing over 90 min. Adiponectin, retinol-binding protein 4 (RBP4), and high-sensitive C-reactive protein (hsCRP) were analyzed. Measurements were performed at baseline and after a 4-week treatment with 160 mg/day valsartan. The results of the IGT and NGT groups were compared.

RESULTS

At baseline, HOMA-IR (IGT 4.1 +/- 3 vs. NGT 2.3 +/- 1.0, P < 0.01), hsCRP (IGT 3.9 +/- 1.9 vs. NGT 1.8 +/- 1 mg/l, P < 0.05), and RBP4 (IGT 27.1 +/- 2.1 vs. NGT 24.0 +/- 2.0 ng/ml, P < 0.05) were significantly higher, whereas ISI (IGT 1.5 +/- 0.9 vs. NGT 1.8 +/- 1.2, P < 0.05) and plasma adiponectin (IGT 3.2 +/- 0.9, NGT 5.2 +/- 2.4 microg/ml, P < 0.05) were significantly lower in the IGT group compared with the NGT group. Under ARB, there was an increase in both groups of adiponectin (IGT 4.1 +/- 1.9 microg/ml, NGT 6.3 +/- 2.9 microg/ml, P < 0.05) and an increase in ISI (IGT 1.5 +/- 0.9 to 2.3 +/- 1 microg/ml, NGT 1.8 +/- 1 to 2.5 +/- 2 microg/ml, P < 0.05). HOMA-IR (4.1 +/- 3 to 2.6 +/- 2; P < 0.01), hsCRP (3.9 +/- 1.9 to 1.8 +/- 1 mg/l, P < 0.05), and RBP4 (27.1 +/- 2.1 to 22.1 +/- 1.8 ng/ml, P < 0.01) decreased significantly in the IGT group.

CONCLUSIONS

Insulin sensitivity and associated inflammatory factors improve under ARB in IGT patients.

Bismuth coating of non-tunneled haemodialysis catheters reduces bacterial colonization: a randomized controlled trial

BACKGROUND

Haemodialysis (HD) catheter-related blood stream infections are a major cause of morbidity and mortality in patients with acute and chronic renal failure.

METHODS

We conducted a randomized, prospective, double-blinded trial investigating the clinical value of bismuth-coated non-tunneled HD catheters in patients in need of temporary short-term vascular access. A standard catheter (SC) was compared to a surface-modified, bismuth-film-coated catheter (FCC). After removal of the catheter for any reason, both arterial and venous lumina were rinsed and the fluid cultured for detection of bacterial colony-forming units (CFU). The catheter tip was placed in a tube containing sterile saline, sonicated and shortly centrifuged to remove debris (3 min at 1000 g). The supernatant was cultured and assayed for DNA content.

RESULTS

Seventy-seven patients in three HD units were randomized. Thirteen patients suffered from acute renal failure, 60 patients from chronic renal failure, and four patients without renal insufficiency were treated with plasma exchange. The time to catheter removal was not significantly different between groups, with a mean of 18.5 +/- 2 days for SC and 15.1 +/- 2 days for FCC. In most cases, the reasons for catheter removal were related to no further need for extracorporeal therapy or establishment of a permanent vascular access. Six catheters for SC and four catheters for FCC were removed because of presumed infection. Bacterial colonization was significantly lower for coated catheters compared to standard catheters, both for cultured catheter tips as well as for CFU in rinse fluids (P < 0.05).

CONCLUSIONS

Surface modification with bismuth film reduces bacterial colonization of temporary non-tunneled HD catheters in a clinical trial. Larger trials with these modified catheters are justified to further investigate the effect on catheter-related infections, complications and costs.