Chemokines and renal disease

Glomerular endothelial glycocalyx-derived heparan sulfate inhibits glomerular leukocyte influx and attenuates experimental glomerulonephritis

Proliferative forms of glomerulonephritis are characterized by the influx of leukocytes, albuminuria, and loss of kidney function. The glomerular endothelial glycocalyx is a thick carbohydrate layer that covers the endothelium and is comprised of heparan sulfate (HS), which plays a pivotal role in glomerular inflammation by facilitating endothelial-leukocyte trafficking. We hypothesize that the exogenous glomerular glycocalyx may reduce the glomerular influx of inflammatory cells during glomerulonephritis. Indeed, administration of mouse glomerular endothelial cell (mGEnC)-derived glycocalyx constituents, or the low-molecular-weight heparin enoxaparin, reduced proteinuria in mice with experimental glomerulonephritis. Glomerular influx of granulocytes and macrophages, as well as glomerular fibrin deposition, was reduced by the administration of mGEnC-derived glycocalyx constituents, thereby explaining the improved clinical outcome. HS_glx also inhibited granulocyte adhesion to human glomerular endothelial cells in vitro. Notably, a specific HS_glx fraction inhibited both CD11b and L-selectin binding to activated mGEnCs. Mass spectrometry analysis of this specific fraction revealed six HS oligosaccharides, ranging from tetra- to hexasaccharides with 2-7 sulfates. In summary, we demonstrate that exogenous HS_glx reduces albuminuria during glomerulonephritis, which is possibly mediated via multiple mechanisms. Our results justify the further development of structurally defined HS-based therapeutics for patients with (acute) inflammatory glomerular diseases, which may be applicable to non-renal inflammatory diseases as well.

RAGE is a critical factor of sex-based differences in age-induced kidney damage

Introduction: Advanced glycation end products (AGEs) are a heterogeneous group of molecules with potential pathophysiological effects on the kidneys. Fibrosis together with the accumulation of AGEs has been investigated for its contribution to age-related decline in renal function. AGEs mediate their effects in large parts through their interactions with the receptor for AGEs (RAGE). RAGE is a transmembrane protein that belongs to the immunoglobulin superfamily and has the ability to interact with multiple pro-inflammatory/pro-oxidative ligands. The role of RAGE in aging kidneys has not been fully characterized, especially for sex-based differences. Methods: Therefore, we analyzed constitutive RAGE knockout (KO) mice in an age- and sex-dependent manner. Paraffin-embedded kidney sections were used for histological analysis and protein expression of fibrosis and damage markers. RNA expression analysis from the kidney cortex was done by qPCR for AGE receptors, kidney damage, and early inflammation/fibrosis factors. FACS analysis was used for immune cell profiling of the kidneys. Results: Histological analysis revealed enhanced infiltration of immune cells (positive for B220) in aged (>70 weeks old) KO mice in both sexes. FACS analysis revealed a similar pattern of enhanced B-1a cells in aged KO mice. There was an age-based increase in pro-fibrotic and pro-inflammatory markers (IL-6, TNF, TGF-β1, and SNAIL1) in KO male mice that presumably contributed to renal fibrosis and renal damage (glomerular and tubular). In fact, in KO mice, there was an age-dependent increase in renal damage (assessed by NGAL and KIM1) that was accompanied by increased fibrosis (assessed by CTGF). This effect was more pronounced in male KO mice than in the female KO mice. In contrast to the KO animals, no significant increase in damage markers was detectable in wild-type animals at the age examined (>70 weeks old). Moreover, there is an age-based increase in AGEs and scavenger receptor MSR-A2 in the kidneys. Discussion: Our data suggest that the loss of the clearance receptor RAGE in male animals further accelerates age-dependent renal damage; this could be in part due to an increase in AGEs load during aging and the absence of protective female hormones. By contrast, in females, RAGE expression seems to play only a minor role when compared to tissue pathology.

Profiling Immune Cells in the Kidney Using Tissue Cytometry and Machine Learning

The immune system governs key functions that maintain renal homeostasis through various effector cells that reside in or infiltrate the kidney. These immune cells play an important role in shaping adaptive or maladaptive responses to local or systemic stress and injury. We increasingly recognize that microenvironments within the kidney are characterized by a unique distribution of immune cells, the function of which depends on this unique spatial localization. Therefore, quantitative profiling of immune cells in intact kidney tissue becomes essential, particularly at a scale and resolution that allow the detection of differences between the various "nephro-ecosystems" in health and disease. In this review, we discuss advancements in tissue cytometry of the kidney, performed through multiplexed confocal imaging and analysis using the Volumetric Tissue Exploration and Analysis (VTEA) software. We highlight how this tool has improved our understanding of the role of the immune system in the kidney and its relevance in the pathobiology of renal disease. We also discuss how the field is increasingly incorporating machine learning to enhance the analytic potential of imaging data and provide unbiased methods to explore and visualize multidimensional data. Such novel analytic methods could be particularly relevant when applied to profiling immune cells. Furthermore, machine-learning approaches applied to cytometry could present venues for nonexhaustive exploration and classification of cells from existing data and improving tissue economy. Therefore, tissue cytometry is transforming what used to be a qualitative assessment of the kidney into a highly quantitative, imaging-based "omics" assessment that complements other advanced molecular interrogation technologies.

Clinical Use of Complement, Inflammation, and Fibrosis Biomarkers in Autoimmune Glomerulonephritis

Introduction

Complement activation, inflammation, and fibrosis play central roles in the mechanisms of injury in autoimmune glomerulonephritis (GN) but they are seldom assessed in epidemiologic studies. The measurement of urinary biomarkers of these pathways of injury could parallel disease activity and add clinical value beyond proteinuria.

Methods

We performed a prospective cohort study of 100 patients with focal and segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), IgA nephropathy (IgAN), lupus nephritis (LN), anti-neutrophil cytoplasmic autoantibody-associated vasculitis (AAV), and membranoproliferative GN (MPGN) followed for 33 (18-54) months. Repeated urinary samples were collected throughout their follow-up to determine proteinuria, urinary sC5b-9, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta 1 (TGF-β1), expressed as creatinine ratios. We identified 177 periods of active and inactive disease based on current remission definitions for each disease.

Results

Urinary sC5b-9, MCP-1, and TGF-β1 were present in each disease. In periods leading to a remission, the reduction of urinary sC5b-9 was 91%, greater than for proteinuria with 76%. During inactive periods, those who did not experience a relapse maintained lower levels of biomarkers compared with those who relapsed. At that time, the increase in urinary sC5b-9 was significantly greater than the rise in proteinuria (8.5-fold increase compared with 3.2-fold) and urinary MCP-1 and TGF-β1. Using current remission definitions for each disease, thresholds for each biomarker were determined using receiver operating characteristic curves. Individuals who averaged levels below these cutoffs during their follow-up had better renal outcomes.

Conclusion

In autoimmune glomerular diseases, urinary sC5b-9, MCP-1, and TGF-β1 are present and parallel disease activity and outcomes. Urinary sC5b-9 appears to be a more discerning marker of immunologic remissions and relapses.

Sex differences in redox homeostasis in renal disease

Sex differences in redox signaling in the kidney present new challenges and opportunities for understanding the physiology and pathophysiology of the kidney. This review will focus on reactive oxygen species, immune-related signaling pathways and endothelin-1 as potential mediators of sex-differences in redox homeostasis in the kidney. Additionally, this review will highlight male-female differences in redox signaling in several major cardiovascular and renal disorders namely acute kidney injury, diabetic nephropathy, kidney stone disease and salt-sensitive hypertension. Furthermore, we will discuss the contribution of redox signaling in the pathogenesis of postmenopausal hypertension and preeclampsia.

Bioinformatics analyses on the immune status of renal transplant patients, a systemic research of renal transplantation

BACKGROUND

Kidney transplantation is the most effective treatment for end-stage renal disease. Allograft rejections severely affect survivals of allograft kidneys and recipients.

METHODS

Using bioinformatics approaches, the present study was designed to investigate immune status in renal transplant recipients. Fifteen datasets from Gene Expression Omnibus (GEO) were collected and analysed. Analysis of gene enrichment and protein-protein interactions were also used.

RESULTS

There were 40 differentially expressed genes (DEGs) identified in chronic rejection group when compared with stable recipients, which were enriched in allograft rejection module. There were 135 DEGs identified in acute rejection patients, compared with stable recipients, in which most genes were enriched in allograft rejection and immune deficiency. There were 288 DEGs identified in stable recipients when compared to healthy subjects. Most genes were related to chemokine signalling pathway. In integrated comparisons, expressions of MHC molecules and immunoglobulins were increased in both acute and chronic rejection; expressions of LILRB and MAP 4 K1 were increased in acute rejection patients, but not in stable recipients. There were no overlapping DEGs in blood samples of transplant recipients.

CONCLUSION

By performing bioinformatics analysis on the immune status of kidney transplant patients, the present study reports several DEGs in the renal biopsy of transplant recipients, which are requested to be validated in clinical practice.

MCP-1 promotes detrimental cardiac physiology, pulmonary edema, and death in the cpk model of polycystic kidney disease

Polycystic kidney disease (PKD) is characterized by slowly expanding renal cysts that damage the kidney, typically resulting in renal failure by the fifth decade. The most common cause of death in these patients, however, is cardiovascular disease. Expanding cysts in PKD induce chronic kidney injury that is accompanied by immune cell infiltration, including macrophages, which we and others have shown can promote disease progression in PKD mouse models. Here, we show that monocyte chemoattractant protein-1 [MCP-1/chemokine (C-C motif) ligand 2 (CCL2)] is responsible for the majority of monocyte chemoattractant activity produced by renal PKD cells from both mice and humans. To test whether the absence of MCP-1 lowers renal macrophage concentration and slows disease progression, we generated genetic knockout (KO) of MCP-1 in a mouse model of PKD [congenital polycystic kidney (cpk) mice]. Cpk mice are born with rapidly expanding renal cysts, accompanied by a decline in kidney function and death by postnatal day 21. Here, we report that KO of MCP-1 in these mice increased survival, with some mice living past 3 mo. Surprisingly, however, there was no significant difference in renal macrophage concentration, nor was there improvement in cystic disease or kidney function. Examination of mice revealed cardiac hypertrophy in cpk mice, and measurement of cardiac electrical activity via ECG revealed repolarization abnormalities. MCP-1 KO did not affect the number of cardiac macrophages, nor did it alleviate the cardiac aberrancies. However, MCP-1 KO did prevent the development of pulmonary edema, which occurred in cpk mice, and promoted decreased resting heart rate and increased heart rate variability in both cpk and noncystic mice. These data suggest that in this mouse model of PKD, MCP-1 altered cardiac/pulmonary function and promoted death outside of its role as a macrophage chemoattractant.

Biomarkers for Chronic Kidney Disease Associated with High Salt Intake

High salt intake has been related to the development to chronic kidney disease (CKD) as well as hypertension. In its early stages, symptoms of CKD are usually not apparent, especially those that are induced in a “silent” manner in normotensive individuals, thereby providing a need for some kind of urinary biomarker to detect injury at an early stage. Because traditional renal biomarkers such as serum creatinine are insensitive, it is difficult to detect kidney injury induced by a high-salt diet, especially in normotensive individuals. Recently, several new biomarkers for damage of renal tubular epithelia such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (Kim-1) have been identified. Previously, we found a novel renal biomarker, urinary vanin-1, in several animal models with renal tubular injury. However, there are few studies about early biomarkers of the progression to CKD associated with a high-salt diet. This review presents some new insights about these novel biomarkers for CKD in normotensives and hypertensives under a high salt intake. Interestingly, our recent reports using spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) fed a high-salt diet revealed that urinary vanin-1 and NGAL are earlier biomarkers of renal tubular damage in SHR and WKY, whereas urinary Kim-1 is only useful as a biomarker of salt-induced renal injury in SHR. Clinical studies will be needed to clarify these findings.

The chemokines secretion and the oxidative stress are targets of low-level laser therapy in allergic lung inflammation

Recent studies show that low-level laser therapy (LLLT) has an important anti-inflammatory action in acute lung inflammation. The present work explored if laser therapy is able to antagonize eosinophils and allergic inflammation induced by oxidative stress in Balb/c mice. Forty-eight hours after challenge, the leukocyte counting, ROS and nitrite/nitrate level, RANTES, CCL3, CCL8 as well as eotaxins were measured in the bronchoalveolar lavage fluid (BALF) of laser-treated mice or not. Into the lung, some chemokines receptors, the iNOS activity and mRNA expression, and the activities of superoxide dismutase (SOD), catalase, gluthatione, NADPH oxidase activities and thiobarbituric acid reactive species (T-Bars) were measured. Laser-treated allergic mice presented reduction of both the ICAM-1 and eosinophil in the lungs. RANTES, CCL8, CCL3 and eotaxins were reduced in BALF of laser-treated allergic mice. In allergic mice lung LLLT decreased the CCR1 and CCR3 and restored the oxidative stress balance as well. Laser decreased the lipidic peroxidation in allergic mice lung as much as increased SOD, GPx and GR. It shows that LLLT on allergic lung inflammation involves leukocyte-attractant chemokines and endogenous antioxidant. Based on results, LLLT may ultimately become a non- invasive option in allergic lung disease treatment. The top figure illustrates the laser decreasing the eosinophils migration into BALF and the bottom figure shows the laser upregulating the expression of heme-oxygenase (anti-oxidant enzyme) in lung tissue anti-oxidant.

Tubular Dickkopf-3 promotes the development of renal atrophy and fibrosis

Renal tubular atrophy and interstitial fibrosis are common hallmarks of etiologically different progressive chronic kidney diseases (CKD) that eventually result in organ failure. Even though these pathological manifestations constitute a major public health problem, diagnostic tests, as well as therapeutic options, are currently limited. Members of the dickkopf (DKK) family, DKK1 and -2, have been associated with inhibition of Wnt signaling and organ fibrosis. Here, we identify DKK3 as a stress-induced, tubular epithelia-derived, secreted glycoprotein that mediates kidney fibrosis. Genetic as well as antibody-mediated abrogation of DKK3 led to reduced tubular atrophy and decreased interstitial matrix accumulation in two mouse models of renal fibrosis. This was facilitated by an amplified, antifibrogenic, inflammatory T cell response and diminished canonical Wnt/β-catenin signaling in stressed tubular epithelial cells. Moreover, in humans, urinary DKK3 levels specifically correlated with the extent of tubular atrophy and interstitial fibrosis in different glomerular and tubulointerstitial diseases. In summary, our data suggest that DKK3 constitutes an immunosuppressive and a profibrotic epithelial protein that might serve as a potential therapeutic target and diagnostic marker in renal fibrosis.

Angiotensin III increases monocyte chemoattractant protein-1 expression in cultured human proximal tubular epithelial cells

BACKGROUND/AIMS

We investigated whether angiotensin III (Ang III) is involved in monocyte recruitment through regulation of the chemokine monocyte chemoattractant protein-1 (MCP-1) in cultured human proximal tubular epithelial cells (HK-2 cells).

METHODS

We measured MCP-1 levels in HK-2 cells that had been treated with various concentrations of Ang III and Ang II type-1 (AT1) receptor antagonists at various time points. The phosphorylation states of p38, c-Jun N-terminal kinases (JNK), and extracellular-signal-regulated kinases were measured in Ang III-treated cells to explore the mitogen-activated protein kinase (MAPK) pathway. MCP-1 levels in HK-2 cell-conditioned media were measured after pre-treatment with the transcription factor inhibitors curcumin or pyrrolidine dithiocarbamate.

RESULTS

Ang III increased MCP-1 protein production in dose- and time-dependent manners in HK-2 cells, which was inhibited by the AT1 receptor blocker losartan. p38 MAPK activity increased significantly in HK-2 cells exposed to Ang III for 30 minutes, and was sustained at higher levels after 60 minutes (p < 0.05). Total phosphorylated JNK protein levels tended to increase 20 minutes after stimulation with Ang III. Pre-treatment with a p38 inhibitor, a JNK inhibitor, or curcumin significantly inhibited Ang III-induced MCP-1 production.

CONCLUSIONS

Ang III increases MCP-1 synthesis via stimulation of intracellular p38 and JNK MAPK signaling activity and subsequent activated protein-1 transcriptional activity in HK-2 cells.

Role of chemokines in proteinuric kidney disorders

Experimental and human studies have shown that proteinuria contributes to the progression of renal disease. Overexposure to filtered proteins promotes the expression and release of chemokines by tubular epithelial cells, thus leading to inflammatory cell recruitment and renal impairment. This review focuses on recent progress in cellular and molecular understanding of the role of chemokines in the pathogenesis of proteinuria-induced renal injury, as well as their clinical implications and therapeutic potential.

Exposure of a distinct PDCA-1+ (CD317) B cell population to agonistic anti-4-1BB (CD137) inhibits T and B cell responses both in vitro and in vivo

4-1BB (CD137) is an important T cell activating molecule. Here we report that it also promotes development of a distinct B cell subpopulation co-expressing PDCA-1. 4-1BB is expressed constitutively, and its expression is increased when PDCA-1⁺ B cells are activated. We found that despite a high level of surface expression of 4-1BB on PDCA-1⁺ B cells, treatment of these cells with agonistic anti-4-1BB mAb stimulated the expression of only a few activation markers (B7-2, MHC II, PD-L2), cytokines (IL-12p40/p70), and chemokines (MCP-1, RANTES), as well as sTNFR1, and the immunosuppressive enzyme, IDO. Although the PDCA-1⁺ B cells stimulated by anti-4-1BB expressed MHC II at high levels and took up antigens efficiently, Ig class switching was inhibited when they were pulsed with T-independent (TI) or T-dependent (TD) Ags and adoptively transferred into syngeneic recipients. Furthermore, when anti-4-1BB-treated PDCA-1⁺ B cells were pulsed with OVA peptide and combined with Vα2⁺CD4⁺ T cells, Ag-specific cell division was inhibited both in vitro and in vivo. Our findings suggest that the 4-1BB signal transforms PDCA-1⁺ B cells into propagators of negative immune regulation, and establish an important role for 4-1BB in PDCA-1⁺ B cell development and function.

Mycophenolate mofetil inhibits macrophage infiltration and kidney fibrosis in long-term ischemia-reperfusion injury

Immunosuppressants have been widely used in renal transplantation, in which ischemia-reperfusion injury is inevitable. Mycophenolate mofetil (MMF) is a relative novel immunosuppressant and also attenuates ischemia-reperfusion injury in the acute phase, but its long-term effects are still obscure. Unilateral renal ischemia-reperfusion injury model was established in Sprague-Dawley rats and 30 mg/kg/day MMF or natural saline was administered a day before the surgery. Renal function was monitored, and histological changes and fibrosis in the kidney were evaluated in both short and long terms. TGF-β1 secretion and MCP-1 expression were determined by immunohistochemistry and real-time PCR respectively. The infiltration of macrophages in renal tissues was also assessed by fluorescence activated cell sorting (FACS). MMF treatment significantly improved renal function in ischemia-reperfusion injury rats in the short and long-term and also effectively prevented interstitial fibrosis. TGF-β1 secretion and MCP-1 expression in the renal tissue of MMF-treated rats were much lower than those in natural saline-treated rats, with much less macrophage infiltration as well. MMF treatment effectively prevented the deterioration of renal function and interstitial fibrosis in ischemia-reperfusion injury rats, which may be associated with decreased TGF-β1, MCP-1 and macrophages. These results provide evidence for the choice of MMF in the renal transplant patients not only for acute renal injury but also for long-term survival of renal allograft.

Chemokines and their receptors in the allergic airway inflammatory process

The development of the allergic airway disease conveys several cell types, such as T-cells, eosinophils, mast cells, and dendritic cells, which act in a special and temporal synchronization. Cellular mobilization and its complex interactions are coordinated by a broad range of bioactive mediators known as chemokines. These molecules are an increasing family of small proteins with common structural motifs and play an important role in the recruitment and cell activation of both leukocytes and resident cells at the allergic inflammatory site via their receptors. Trafficking and recruitment of cell populations with specific chemokines receptors assure the presence of reactive allergen-specific T-cells in the lung, and therefore the establishment of an allergic inflammatory process. Different approaches directed against chemokines receptors have been developed during the last decades with promising therapeutic results in the treatment of asthma. In this review we explore the role of the chemokines and chemokine receptors in allergy and asthma and discuss their potential as targets for therapy.

Role of Salvia miltiorrhiza for Modulation of Th2-derived Cytokines in the Resolution of Inflammation

Background

Salvia miltiorrhiza (SM) has been used to treat inflammatory diseases including edema and arthritis; however, the anti-inflammatory mechanism of SM action remains unresolved.

Methods

The effects of an ethanol extract of SM (ESM) on pro-inflammatory cytokines such as TNF-α, IL-1β, IL-6, and NO, on anti-inflammatory cytokines including IL-4, IL-10, TGF-β, and IL-1Ra have been studied in an attempt to elucidate the anti-inflammatory mechanism in murine macrophages.

Results

ESM inhibited the production of pro-inflammatory cytokines via down-regulation of gene and protein expression whereas it increased the anti-inflammatory cytokines. Furthermore, ESM inhibited the expression of the chemokines, RANTES and CX3CL1, as well as of inflammatory mediators such as TLR-4 and 11β-HSD1.

Conclusion

These results indicated that the regulatory effects of ESM may be mediated though the suppression of pro-inflammatory cytokines as well as the induction of anti-inflammatory cytokines. Consequently, we speculate that ESM has therapeutic potential for inflammation-associated disorders.

Acute pyelonephritis and renal scarring are caused by dysfunctional innate immunity in mCxcr2 heterozygous mice

The CXCR1 receptor and chemokine CXCL8 (IL-8) support neutrophil-dependent clearance of uropathogenic Escherichia coli from the urinary tract. CXCR1 is reduced in children prone to pyelonephritis, and heterozygous hCXCR1 polymorphisms are more common in this patient group than in healthy individuals, strongly suggesting a disease association. Since murine CXCR2 (mCXCR2) is functionally similar to human CXCR1, we determined effects of gene heterozygosity on the susceptibility to urinary tract infection by infecting heterozygous (mCxcr2(+/-)) mice with uropathogenic Escherichia coli. Clearance of infection and tissue damage were assessed as a function of innate immunity in comparison to that in knockout (mCxcr2(-/-)) and wild-type (mCxcr2(+/+)) mice. Acute sepsis-associated mortality was increased and bacterial clearance drastically impaired in heterozygous compared to wild-type mice. Chemokine and neutrophil responses were delayed along with evidence of neutrophil retention and unresolved kidney inflammation 1 month after infection. This was accompanied by epithelial proliferation and subepithelial fibrosis. The heterozygous phenotype was intermediate, between knockout and wild-type mice, but specific immune cell infiltrates that accompany chronic infection in knockout mice were not found. Hence, the known heterozygous CXCR1 polymorphisms may predispose patients to acute pyelonephritis and urosepsis.

Polymorphism of proinflammatory cytokine genes and albuminuria in the Japanese general population: the Takahata study

BACKGROUND

A cluster of proinflammatory cytokines plays an important role in the development of various renal diseases, and the expression of these cytokines is genetically modified. To examine the association between polymorphisms of proinflammatory cytokine genes and albuminuria, a cross-sectional study was conducted in the general population.

METHODS

Single nucleotide polymorphisms (SNPs) in six proinflammatory cytokine genes, including interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, CC chemokine ligand 1 (CCL1) and monocyte chemoattractant protein-1 (MCP-1), were genotyped in 2927 Japanese subjects. Urine albumin-creatinine ratio (UACR) was measured in morning spot urine samples.

RESULTS

Albuminuria (UACR ≥ 30 mg/g) was significantly associated with the A/A + A/G genotype at rs2069852 in the IL-6 gene (P = 0.01) and the A/A genotype at rs228269 in the CCL1 gene (P = 0.002). Multivariate analysis with adjustment for traditional risk factors showed that these genotypes independently predicted albuminuria [odds ratio (OR) 1.782, 95% confidence interval (CI) 1.171-2.712, P = 0.007 for the A/A + A/G genotype at rs2069852 in IL-6, and OR 1.432, 95% CI 1.128-1.770, P = 0.003 for the A/A genotype at rs228269 in CCL1]. The prevalence of albuminuria and the UACR were increased along with the increase of risk genotypes.

CONCLUSIONS

This study revealed that SNPs in the IL-6 and CCL1 genes were associated with albuminuria, and the combination of these genotypes had an additive effect on the prevalence and severity of albuminuria. This indicates that genetic factors influencing inflammatory responses may affect the development of renal injury in the Japanese general population.

Chemokine (CCR) and fractalkine (CX3CR) receptors and end stage renal disease

OBJECTIVE AND DESIGN

Genetic polymorphisms of chemokines and their receptors were reported to be independent risk factors for inflammation associated disease. We explored the role of CCR5-Δ32, CCR5-G59029A, CX3CR1 V249I and T280M gene polymorphisms as susceptibility for end stage renal disease (ESRD).

SUBJECTS AND METHODS

We genotyped 258 ESRD and 569 healthy controls by sequence-specific primers and RFLP and examined their association.

RESULTS

There was significant difference in genotype frequencies of CCR5-G59029A (p = 0.005), and CX3CR1 V249I (p < 0.0001) between ESRD and controls. No homozygous individuals were observed for CCR5-Δ32. The haplotype analysis of all four studied genes reveled that haplotype +/A/T/I was more significant in patients and associated with higher risk (OR = 2.95) of ESRD. Further, the haplotype of CX3CR1 (T280M, V249I) gene showed 3.6-fold higher in an individual carrying T/I haplotype. No risk was seen for CCR5 haplotypes.

CONCLUSIONS

These results highlight the role of CCR5 and CX3CR1 in ESRD.

Upper urinary tract infections are associated with RANTES promoter polymorphism

We evaluated the association between MCP-1, CCR2, RANTES, and CCR5 gene polymorphisms and upper urinary tract infection in 273 children recruited in Northeast Italy. Statistical analysis of RANTES-403 G>A genotype frequencies showed that children carrying the RANTES-403 G allele are at higher risk for urinary tract infection, irrespective of vesicoureteral reflux.

The cardiorenal syndrome: making the connection

The heart and the kidneys share responsibility for maintaining hemodynamic stability and end-organ perfusion. Connections between these organs ensure that subtle physiologic changes in one system are tempered by compensation in the other through a variety of pathways and mediators. In the setting of underlying heart disease or chronic kidney disease, the capacity of each organ to respond to perturbation caused by the other may become compromised. This has recently led to the characterization of the cardiorenal syndrome (CRS). This review will primarily focus on CRS type 1 where acute decompensated heart failure (ADHF) results in activation of hemodynamic and neurohormonal factors leading to an acute drop in the glomerular filtration rate and the development of acute kidney injury. We will examine the scope and impact of this problem, the pathophysiology associated with this relationship, including underperfuson and venous congestion, diagnostic tools for earlier detection, and therapeutic interventions to prevent and treat this complication.

Expression and function of the C-class chemokine lymphotactin (XCL1) in Wegener's granulomatosis

OBJECTIVE

In Wegener's granulomatosis (WG), vasculitic lesions are characterized by prominent infiltration of polymorphonuclear neutrophils (PMN) and T cells, but underlying pathogenic mechanisms remain to be defined. We analyzed the expression and functional role of the C-class chemokine lymphotactin, XCL1, in WG.

METHODS

Sera and peripheral blood mononuclear cells (PBMC) were obtained from 16 patients with WG and healthy controls. Serum XCL1 concentrations were measured by ELISA. PBMC were subjected to flow cytometry for activation markers and immunophenotype of XCL1+ T cells. Renal biopsies were analyzed by double-label immunohistochemistry. In vitro stimulation of PMN with XCL1 was performed to study its function.

RESULTS

Flow cytometry demonstrated coexpression of the activation markers CD25, CD69, and HLA-DR in a significantly higher proportion of T cells in WG patients in comparison to controls. XCL1 was found to be mainly expressed in CD4+CD28- T cells in WG patients. In renal biopsies, the presence of XCL1 was only detected within interstitial CD4+ and CD8+ T cells. Functional studies demonstrated a significant enhancement of IL-8 production in isolated PMN after in vitro stimulation with XCL1. There were no significant differences in XCL1 serum concentrations between WG patients and controls (p = 0.88).

CONCLUSION

Our data indicated increased expression of XCL1 in CD4+ and CD8+ T cells in WG. Considering its function as a lymphocyte-specific chemoattractant, XCL1 might be a key modulator of T cell recruitment in WG. Functional studies further suggest that XCL1 may support vascular inflammation by induction of release of interleukin 8 in PMN.

Effect of Zanthoxylum schinifolium on TNF-alpha-induced vascular inflammation in human umbilical vein endothelial cells

Pro-inflammatory cytokines induce the injury of endothelial cells in response to increases of adhesion molecules, leading to vascular inflammation and the development of atherosclerosis. In this study, we evaluated an ethanol extract of Zanthoxylum schinifolium (EZS) to determine if it inhibits the expressions of cellular adhesion molecules in human umbilical vein endothelial cells (HUVEC). When pretreatment of HUVEC with EZS, EZS suppressed the expression levels of cell adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-), and E-selectin induced by TNF-alpha. The adhesion of HL-60 cells to TNF-alpha-induced endothelial cells was decreased significantly in a concentration-dependent manner. Furthermore, TNF-alpha-induced MCP-1 and IL-8 mRNA expression levels were also attenuated by pretreatment with EZS. In addition, EZS suppressed TNF-alpha-induced production of reactive oxygen species (ROS). EZS inhibited NF-kappaB activation and IkappaB-alpha phosphorylation induced by TNF-alpha, subsequent degradation of IkappaB-alpha. Finally, EZS inhibited TNF-alpha-induced p38 MAPK and c-Jun N-terminal kinase (JNK) phosphorylation. Taken together, these results demonstrate that EZS suppresses vascular inflammatory process, which may be closely related to the inhibition of ROS, JNK, p38 MAPK and NF-kappaB activation in HUVEC.

Expression of JAKs/STATs pathway molecules in rat model of rapid focal segmental glomerulosclerosis

The objective of this study was to investigate the role of the Janus kinase-signal transducers and activators of transcription (JAKs/STATs) pathway in focal segmental glomerulosclerosis. Sixty specific pathogen-free male Wistar rats were randomly divided into two groups: a model group (MG) and a control group (CG). In the MG group, nephropathy was induced by unilateral nephrectomy and a single tail vein injection of adriamycin (5 mg/kg). Ten rats were sacrificed every 2 weeks in each group. The expressions of smooth muscle alpha actin (alpha-SMA), collagen (COL)-IV, STAT1, and STAT3 were examined using histochemical techniques, and Western blotting was used to examine the protein levels of STAT1, STAT3, phosphorylated (P)-STAT1, P-STAT3, and transforming growth factor beta1 (TGFbeta(1)). The expressions of JAK1, JAK2, STAT1, STAT3, suppressors of cytokine signaling (SOCS)1, SOCS3, protein inhibitors of activated STAT (PIAS)1, and PIAS3 were also measured by real-time quantitative reverse transcriptase-PCR. A steady and significant increase in the expressions of alpha-SMA, COL-IV and TGFbeta(1) were observed in MG rats over the whole experimental course. Increased STAT1 and P-STAT1 levels in MG rats were observed by week 6, whereas increased levels of STAT3 and P-STAT3 were noted by week 2. At the mRNA levels, JAK1, STAT1, and PIAS1 were significantly increased in MG rats in week 2, whereas JAK2 mRNA showed a significant decrease by weeks 2 and 4, followed by an significant increase in week 6. Significantly increased STAT3 levels were noted in week 2, followed by a steady and significant decrease in weeks 4 and 6. Significantly reduced levels of SOCS1, SOCS3, and PIAS3 mRNA were noted at all time points. We conclude that the JAKs/STATs signaling pathway may play an important role in the pathological process of rapid focal segmental glomerulosclerosis in the rat model.

The Importance of Glomerular Deposits of Von Willebrand Factor in Human Renal Allografts

OBJECTIVE

The aim of this study was to evaluate the importance of glomerular expression of von Willebrand factor (vWF) in human renal allografts.

METHODS

We investigated graft biopsies from 72 renal transplant recipients, 40 with acute rejection (AR) and 32 with chronic allograft nephropathy (CAN). All biopsy specimens were immunostained with vWF and CD68 and graded using 3-tiered scales. The follow-up biopsies of patients with AR were reevaluated for development of glomerular sclerosis.

RESULTS

A significant difference was found between type 1 and type 2 AR with regard to glomerular vWF expression (P < 0.01). None of the patients with type 1 AR showed mesangial vWF expression, but 36.4% of patients with type 2 AR showed segmental mesangial vWF expression. In follow-up biopsies, 18 of 40 patients developed significant glomerular sclerosis, and patients with mesangial vWF expression (grade 3 GvWF) showed glomerular sclerosis earlier than did others (P < 0.01). In addition, the outcome for grafts that showed grade 3 glomerular vWF was significantly worse than was the outcome noted for grafts that showed grade 1 or grade 2 glomerular vWF (P < 0.001). Half of the biopsy specimens in the CAN group showed global mesangial vWF expression. Glomerular macrophage infiltration was correlated with degree of glomerular vWF expression both in the AR and in the CAN groups (P < 0.05, P= 0.001, respectively).

CONCLUSION

We hypothesized that the increasing amount of glomerular vWF may be used as a marker of acute vascular rejection and may help for the evaluation of renal allograft biopsies without sufficient arteries. In addition, it can also be a marker for development of early glomerular sclerosis and may help us determine which patients are in need of further treatment.

Genetic interactions between the donor and the recipient for susceptibility to acute rejection in kidney transplantation: polymorphisms of CCR5

BACKGROUND

Acute rejection (AR) contributes to the development of chronic allograft nephropathy that is the major cause of graft failure. We analyzed the 59029G>A polymorphism and an internal 32 bp deletion (CCR5 32) of CCR chemokine receptor 5 (CCR5) Delta and tried to prove the hypothesis that genetic interactions between the donor and the recipient influence the development of AR.

METHODS

We detected genetic polymorphisms by the TaqMan(R) method and by sizing PCR amplicons (n = 486). The primary outcomes were early acute rejection (EAR) and repeated early acute rejection (RR). We defined EAR as the occurrence of a biopsy-proven AR within 3 months after transplantation.

RESULTS

The development of EAR was dependent on the number of A alleles in recipients and showed a dose-response relationship (P = 0.002). When we combined the number of A alleles in both donor and recipient, episodes of EAR and RR were more prevalent as the allelic number increased (A allelic number 0 & 1, 2 versus 3 & 4, P = 0.048; 0 & 1 versus 3 & 4, P = 0.006). Statistical significance was preserved after multivariate analysis of sex, HLA mismatch and type of donor with the recipient's age as the continuous term. Also, graft survival was different according to the presence of the A allele, i.e. recipients carrying A allele (+) grafts showed poor graft survival (P = 0.008 by a log-rank test). Again, the number of A alleles affected graft survival as the recipients who carried more A alleles had poor graft survival (A allele number 0 & 1 versus 2 versus 3 & 4, P = 0.011; 0 & 1 versus 3 & 4, P = 0.08; 0 & 1 versus 2, P = 0.002; by a log-rank test). All of the participants were wild-type homozygotes for CCR5Delta32.

CONCLUSIONS

The A allele of CCR5 59029G>A was a risk factor for EAR and RR. As the number of A alleles increased, episodes of EAR were more frequently observed.

Role of FTY720 on M1 and M2 macrophages, lymphocytes, and chemokines in 5/6 nephrectomized rats

Renal injury is accompanied by the presence of infiltrating inflammatory cells in the glomerulus and tubulointerstitium. FTY720 modifies lymphocyte migration into injured tissues by lymphocyte sequestration to secondary lymphoid organs. The purpose of this study was to examine the potential of FTY720 to influence the inflammatory response in a nonimmunological model of renal failure. Sham-operated and 5/6 nephrectomized (SNX) Sprague-Dawley rats received two different doses of FTY720 or vehicle orally for 14 wk. Treatment with FTY720 reduced glomerular and tubulointerstitial damage in SNX rats but failed to stabilize creatinine clearance. The increase in gene expression of chemokine receptors CCR1, CCR2, and CCR5 in kidneys of vehicle-treated SNX rats was significantly attenuated by high-dose FTY720. Treatment with high-dose FTY720 tended to normalize RANTES and MCP-1 renal gene expression. FTY720 affected not only glomerular and tubulointerstitial lymphocytes, but M1 and M2 phenotype macrophages were also reduced. FTY720 significantly reduced key mediators of renal inflammation and fibrosis. FTY720 also decreased immunoregulation of M2 macrophages, which are beneficial for tissue remodeling and repair.

Increased urinary levels of CXCL5, CXCL8 and CXCL9 in patients with Type 2 diabetic nephropathy

CXC chemokines are particularly significant for leukocyte infiltration in inflammatory diseases. Recent reports have shown that inflammation is one of potential pathogenic mechanisms for diabetic nephropathy. However, information on inflammation related with CXC chemokines in human Type 2 diabetic nephropathy still remains scarce. We measured urinary and serum levels of three CXC chemokines, CXCL5, CXCL8 and CXCL9, in 45 Type 2 diabetic patients (DM), 42 primary renal disease (PRD) patients and 22 healthy controls by enzyme-linked immunosorbent assay. Urinary levels of CXCL5, CXCL8 and CXCL9 in DM were significantly elevated compared to those in controls (P<.0001, P<.01, P<.001; respectively). They increased consistent with urinary albumin excretion rate (UAER) and correlated with UAER in partial correlation analyses (r=0.41, P<.01; r=0.40, P<.01; r=0.45, P<.01; respectively). Urinary levels of CXCL5 in DM were significantly interrelated to HbA(1c) (r=0.42, P<.01). On the other hand, PRD showed significant increased levels of urinary CXCL8 and CXCL9 compared to controls (P<.001, P<.01; respectively), and so did PRD as UAER increased. However, there were no significant elevations of urinary levels of CXCL5 in PRD in spite of the increased UAER. We found significant associations of UAER in DM with diabetes duration, 1/serum creatinine, urinary CXCL5 (adjusted R(2)=0.67, P<.0001) or CXCL9 (adjusted R(2)=0.69, P<.0001) in a stepwise multiple regression analysis. These results suggest that these three CXC chemokines may be involved in the progression of human Type 2 diabetic nephropathy and that CXCL5 may be of use for telling diabetic nephropathy from primary renal diseases.

Cytokine (IL-10 -1082 and -819) and chemokine receptor (CCR2 and CCR5) gene polymorphism in North Indian patients with end-stage renal disease

End-stage renal disease (ESRD) is associated with the inflammatory state characterized by infiltrating macrophages/lymphocytes, a major source of cytokines and chemokines. This study examined the role of genetic polymorphisms in cytokine, IL-10, and chemokine receptors, CCR2 and CCR5, with susceptibility to ESRD. Polymorphisms in IL-10 (-1082 G/A, PCR-RFLP; -819 C/T, ARMS-PCR), CCR2 (Val/Ile, PCR-RFLP), and CCR5Delta32 were detected in 184 ESRD patients and 180 controls. Our results demonstrated a significant difference in genotype frequencies of IL-10 -1082G/A (p<0.001), IL-10 -819C/T (p=0.007), and CCR2Val/Ile (p=0.033) between ESRD patients and controls. However, only low-producing genotype AA of IL-10 -1082G/A showed significantly threefold higher risk for all ESRD patients (odds ratio [OR]=3.164, 95%CI=1.74-5.72) as well as patients with only inflammatory causes of renal diseases (OR=2.979, 95%CI=1.61-5.52). No risk was seen in variant genotype of other genes. The genotypic frequencies of CCR5Delta32 were comparable in patients and controls (p=0.203). In haplotype analysis, A-T haplotype (low producer) of IL-10 showed 1.7-fold risk (p>0.05). No risk was seen for CCR2 and CCR5 haplotypes. The AA genotype of IL-10 -1082G/A polymorphism was associated with increased susceptibility to ESRD. This study implies the basis for defined antiinflammatory approaches to impede renal disease progression.

Differential regulation of chemokine CCL5 expression in monocytes/macrophages and renal cells by Y-box protein-1

The Y-box protein-1 (YB-1) belongs to the family of cold shock proteins that have pleiotropic functions such as gene transcription, RNA splicing, and mRNA translation. YB-1 has a critical role in atherogenesis due to its regulatory effects on chemokine CCL5 (RANTES) gene transcription in vascular smooth muscle cells. Since CCL5 is a key mediator of kidney transplant rejection, we determined whether YB-1 is involved in allograft rejection by manipulating its expression. In human kidney biopsies, YB-1 transcripts were amplified 17-fold in acute and 21-fold in chronic allograft rejection with a close correlation between CCL5 and YB-1 mRNA expression in both conditions. Among three possible YB-1 binding sites in the CCL5 promoter, a critical element was mapped at -28/-10 bps. This site allowed up-regulation of CCL5 transcription in monocytic THP-1 and HUT78 T-cells and in human primary monocytes; however, it repressed transcription in differentiated macrophages. Conversely, YB-1 knockdown led to decreased CCL5 transcription and secretion in monocytic cells. We show that YB-1 is a cell-type specific regulator of CCL5 expression in infiltrating T-cells and monocytes/macrophages and acts as an adaptive controller of inflammation during kidney allograft rejection.

The preventive effect of Met-RANTES on postoperative intraperitoneal adhesion formation in the rat model

BACKGROUND

Chemokines are proinflammatory proteins that participate in immune and inflammatory responses through chemoattraction and leukocyte activation. The chemokine antagonist Met-RANTES (Regulated upon Activation Normal T cell Expressed and Secreted) has been shown to be efficacious in decreasing inflammation in several animal disease models. The purpose of this study was to investigate the effects of administration of Met-RANTES on intra-abdominal adhesion formation after abdominal operation.

MATERIALS AND METHODS

A 42 and 4-month-old female Wistar-Albino rats were subjected to standardized lesions by cauterization of the cecum and uterine horn. They were divided randomly into 3 groups containing 14 rats each: group 1 (control), operative procedure without further treatment; group 2 (Seprafilm), operative procedure with an antiadhesive membrane; 2 x 1 cm of Seprafilm was interposed beneath the peritoneal incision, and group 3 (Met-RANTES), operative procedure with the chemokine antagonist Met-RANTES. The extent and severity of adhesions at the operative site were evaluated. Light microscopic examination was performed to determine semiquantitative scores of VEGF expression.

RESULTS

Rats in the control group formed extensive adhesions. In comparison with the control group, the adhesion scores were significantly lower in the 2 other groups. The immunohistochemical grading scores of vascular endothelial growth factor correlated closely with the total adhesion scores and were less in groups 2 and 3 (P < .005).

CONCLUSIONS

Selective chemokine suppression with Met-RANTES seems to decrease rates, extent, and severity of postoperative intraperitoneal adhesions.

Association of CC chemokine ligand 5 genotype with urinary albumin excretion in the non-diabetic Japanese general population: the Takahata study

Albuminuria is an early marker of vascular damage, and its development in diabetic nephropathy is associated with genotype of inflammatory CC chemokine ligand 5 (CCL5). This study investigated whether the association of CCL5 and albuminuria is a general phenomenon. We characterized a Japanese population consisting of 2,749 non-diabetic individuals over 40 years in Takahata, Japan. The urine albumin-creatinine ratio (UACR) was obtained from morning spot urine. We genotyped SNPs within the CCL5 gene that displayed frequent minor allele frequencies in Japanese (i.e., rs2107538, rs2280789, rs3817655 and rs9909416). Assessment of possible association and linkage disequilibrium (LD) revealed that all four SNP genotypes are correlated significantly with UACR (P = 0.004-0.005), and these four SNPs variations showed an obvious consistency of genotypes by detecting almost complete linkage disequilibrium (D' = 1 and r (2) > 0.95). We found two exclusive haplotypes in the CCL5 gene (haplotype1: rs2107538G/rs2280789T/rs3817655T/rs9909416G, frequency 0.64 and haplotype2: rs2107538A/rs2280789C/rs3817655A/rs9909416A, frequency 0.35) among the population. A significant association with elevated UACR was identified with haplotype1 (P = 0.002). Homozygotes for haplotype1 displayed strikingly-elevated UACR (48.5 +/- 6.6 mg/g, n = 1,116) compared to the rest (28.6 +/- 1.6 mg/g, n = 1,530) (P = 0.001). In conclusion, these results suggested that genetic variation of CCL5 might be an important risk factor for albuminuria in the non-diabetic Japanese general population.

Heparan sulfate domains on cultured activated glomerular endothelial cells mediate leukocyte trafficking

Heparan sulfate (HS) proteoglycans by playing key roles in the leukocyte-endothelial interactions are thought to mediate inflammatory cell influx in proliferative glomerulonephritis. Here, we evaluated the specific features within glomerular endothelial HS that promote leukocyte adhesion. Mouse and human glomerular endothelial cells activated by tumor necrosis factor (TNF)-alpha or interleukin (IL)-1beta increased expression of inflammatory N- and 6-O-sulfated HS domains. In addition, altered expression of HS-modifying enzymes occurred, a feature also found in mouse kidneys with anti-glomerular basement membrane disease or lupus nephritis. Inhibition of the nuclear factor (NF)-kappaB pathway repressed cytokine-induced alterations in HS and gene expression of modifying enzymes. Firm adhesion of leukocytes to activated mouse glomerular endothelial cells decreased after removal of endothelial HS or addition of sulfated heparinoids. Specific antibodies that block N- and 6-O-sulfated HS domains on activated mouse endothelial cells reduced the number of rolling and firmly adhering leukocytes under dynamic flow conditions, while they increased the average leukocyte-rolling velocity. Our study shows that N- and 6-O-sulfated domains in HS on activated glomerular endothelium are crucial for leukocyte trafficking and are possible therapeutic targets.

Inhibition of CXCL16 attenuates inflammatory and progressive phases of anti-glomerular basement membrane antibody-associated glomerulonephritis

Chemokines recruit and activate leukocytes during inflammation. CXCL16 is a recently discovered chemokine that is expressed as a transmembrane protein that is cleaved to form the active, soluble chemokine. We analyzed the role of CXCL16 in the development of inflammation and in the progression of the anti-glomerular basement membrane (GBM) antibody-induced experimental glomerulonephritis in Wistar-Kyoto rats. CXCL16 was expressed in glomerular endothelial cells and mediated adhesion of macrophages expressing CXCL16 and its cognate receptor, CXCR6. Glomerular infiltrates displayed a strong migratory response to soluble CXCL16. Soluble CXCL16 and its receptor CXCR6 were induced in nephritic glomeruli throughout the disease, and CXCL16 expression correlated with the up-regulation of ADAM10, suggesting that this disintegrin and metalloproteinase mediates the chemokine activity of CXCL16. Blocking CXCL16 in the acute inflammatory phase or progressive phase of established glomerulonephritis significantly attenuated monocyte/macrophage infiltration and glomerular injury; proteinuria also improved. We conclude that CXCL16/CXCR6 plays a critical role in stimulating leukocyte influx, which causes glomerular damage during anti-GBM glomerulonephritis. Blocking CXCL16 actions limits the progression of anti-GBM glomerulonephritis even when the disease is established.

Association of TGFbeta1, TNFalpha, CCR2 and CCR5 gene polymorphisms in type-2 diabetes and renal insufficiency among Asian Indians

Background

Cytokines play an important role in the development of diabetic chronic renal insufficiency (CRI). Transforming growth factor β1 (TGF β1) induces renal hypertrophy and fibrosis, and cytokines like tumor necrosis factor-alpha (TNFα), chemoattractant protein-1 (MCP-1), and regulated upon activation and normal T cell expressed and secreted (RANTES) mediate macrophage infiltration into kidney. Over expression of these chemokines leads to glomerulosclerosis and interstitial fibrosis. The effect of MCP-1 and RANTES on kidney is conferred by their receptors i.e., chemokine receptor (CCR)-2 and CCR-5 respectively. We tested association of nine single nucleotide polymorphisms (SNPs) from TGFβ1, TNFα, CCR2 and CCR5 genes among individuals with type-2 diabetes with and without renal insufficiency.

Methods

Type-2 diabetes subjects with chronic renal insufficiency (serum creatinine ≥ 3.0 mg/dl) constituted the cases, and matched individuals with diabetes of duration ≥ 10 years and normoalbuminuria were evaluated as controls from four centres in India. Allelic and genotypic contributions of nine SNPs from TGFβ1, TNFα, CCR2 and CCR5 genes to diabetic CRI were tested by computing odds ratio (OR) and 95% confidence intervals (CI). Sub-analysis of CRI cases diabetic retinopathy status as dependent variable and SNP genotypes as independent variable in a univariate logistic regression was also performed.

Results

SNPs Tyr81His and Thr263Ile in TGF β1 gene were monomorphic, and Arg25Pro in TGF β1 gene and Δ32 polymorphism in CCR5 gene were minor variants (minor allele frequency <0.05) and therefore were not considered for case-control analysis. A significant allelic association of 59029G>A SNP of CCR5 gene has been observed and the allele 59029A seems to confer predisposition to development of diabetic CRI (OR 1.39; CI 1.04–1.84). In CRI subjects a compound group of genotypes "GA and AA" of SNP G>A -800 was found to confer predisposition for proliferative retinopathy (OR 3.03; CI 1.08–8.50, p = 0.035).

Conclusion

Of the various cytokine gene polymorphisms tested, allele 59029A of CCR5 gene is significantly associated with diabetic renal insufficiency among Asian Indians. Result obtained for 59029G>A SNP of CCR5 gene is in conformity with reports from a Japanese population but due to sub-optimal power of the sample, replication in larger sample set is warranted.

Human microvascular endothelial synthesis of interleukin-8 during in vitro ischemia and reperfusion

These studies were undertaken to evaluate human microvascular endothelial cell (MEC) synthesis of interleukin-8 (IL-8), a potent neutrophil chemoattractant, under in vitro conditions of ischemia and reperfusion. IL-8 and other related CXC chemokines are believed to mediate tissue injury in a variety of pathologic conditions in humans. MEC grown on microcarrier beads were exposed to 3 or 6 h of in vitro ischemia followed by 2 h of reperfusion. Conditioned medium, MEC protein, and total RNA extracts were assayed for IL-8 using an ELISA. During ischemia alone, MEC increased intracellular, but not extracellular levels of IL-8 secretion. In contrast, reperfusion markedly stimulated both intracellular and extracellular IL-8 secretion. Neither 3 h of ischemia alone or followed by reperfusion altered steady-state levels of IL-8 mRNA when compared to pre-ischemic levels. In contrast, after 6 h of ischemia alone and ischemia followed by reperfusion, IL-8 mRNA was increased eight- and sixfold, respectively, when compared to pre-ischemic levels. These studies demonstrate an inverse relationship between the rate of IL-8 protein secretion and the steady-state levels of IL-8 mRNA during ischemia and reperfusion. During ischemia and reperfusion both the increase in cell-associated IL-8 protein and the release of IL-8 into the medium is dependent on de novo protein synthesis rather than the intracellular accumulation of IL-8. These experiments indicate that post-ischemic modulation of IL-8 release and synthesis following ischemia reperfusion will require strategies directed towards inhibition of IL-8 transcription and in depth knowledge of the mechanisms regulating IL-8 secretion.

Fimbrial lectins influence the chemokine repertoire in the urinary tract mucosa

The defense against mucosal infections relies on chemokines that recruit inflammatory cells to the mucosa. This study examined if the chemokine response to uro-pathogenic Escherichia coli is influenced by fimbrial expression. The CXC (CXCL1, CXCL5, CXCL8, CXCL9, CXCL10) and CC chemokines (CCL2, CCL3, CCL5) were quantified after in vitro infection of uro-epithelial cells with a fimbriated E. coli pyelonephritis isolate, or with P or type 1 fimbriated transformants of an avirulent E. coli K-12 strain. The response profile was shown to vary with the fimbrial type. Type 1 fimbriated E. coli elicited mainly CXCL1 and CXCL8, whereas P fimbriated E. coli stimulated CCL2 and CCL5 and class II were more potent chemokine inducers than class III P fimbriae. Chemokines were also quantified in urine samples from 73 patients with febrile urinary tract infection, and analyzed as a function of disease severity and fimbrial expression by the strain infecting each patient. A complex CXC and CC chemokine response was detected in patient urine, with a significant influence of the fimbrial type. The results show that virulence factors like fimbriae may modify the mucosal chemokine response. This mechanism may allow the host to adjust the inflammatory cell infiltrate to fit the infecting strain.

Heme-oxygenase upregulation ameliorates angiotensin II-induced tubulointerstitial injury and salt-sensitive hypertension

BACKGROUND

Heme oxygenase-1 (HO-1) has been implicated in the modulation of several diseases including hypertension (HTN) and renal injury. The tubulointerstitial (TI) injuries are supposed to be the main determinants for the development of salt-sensitive HTN. Therefore, this study examined the role of HO-1 in angiotensin II (AngII)-induced TI injury and salt-sensitive HTN.

METHODS

Sprague-Dawley rats on a high salt diet were treated by AngII infusion plus either hemin, an inducer of HO-1, or hemin + zinc protoporphyrin, a HO-1 inhibitor, for 2 weeks, and then followed for 6 weeks.

RESULTS

The AngII infusion resulted in acute HTN and proteinuria. Light microscopy revealed focal areas of tubular atrophy with mononuclear cell infiltration and interstitial expansion. The overexpression of osteopontin and TGF-beta(1) accompanied by diminished expression of rat endothelial cell antigen-1, the hallmarks of TI injury, were observed. At 2 weeks, all interventions were withdrawn and systolic blood pressure returned towards normal. After a brief normal salt diet, rats were again placed on high salt diet, resulting in progressive increase in systolic blood pressure in the HO-1-inhibited group.

CONCLUSION

The induction of HO-1 attenuated the development of HTN, suggesting that HO-1 plays a crucial role in significant attenuation of AngII-mediated TI injury and resultant salt-sensitive HTN.

Lysophospholipids increase IL-8 and MCP-1 expressions in human umbilical cord vein endothelial cells through an IL-1-dependent mechanism

Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are both low-molecular-weight lysophospholipid (LPL) ligands which are recognized by the Edg family of G protein-coupled receptors (GPCRs). In endothelial cells, these two ligands activate Edg receptors resulting in cell proliferation and cell migration. Interleukin-8 (IL-8) is a C-X-C chemokine and acts as a chemoattractant of neutrophils, whereas monocyte chemoattractant protein-1 (MCP-1) is a C-C chemokine and functions mainly as a chemoattractant of monocytes/macrophages. Both factors are secreted from endothelial cells and have been implicated in the processes leading to atherosclerosis. We examined the effects of LPLs on the expression of IL-8 and MCP-1, key regulators of leukocyte recruitment in human umbilical cord vein endothelial cells (HUVECs). Work illustrated in this article showed that LPA and S1P enhanced IL-8 and MCP-1 mRNA expressions, and protein secretions in dose- and time-dependent fashions. Maximal mRNA expression appeared at 16 hr post-ligand treatment. Using prior treatments with chemical inhibitors, LPLs enhanced IL-8 and MCP-1 expressions through a Gi-, Rho-, and NFkappaB-dependent mechanism. In a chemotaxis assay system, LPL treatments of endothelial cells enhanced monocyte recruitment through upregulating IL-8 and MCP-1 protein secretions. Pre-incubation with AF12198, an IL-1 receptor antagonist or IL-1 functional blocking antibody both suppressed the enhanced effects elicited by LPLs of IL-8 and MCP-1 mRNA expressions in HUVECs. These results suggest that LPLs released by activated platelets might enhance the IL-8- and MCP-1-dependent chemoattraction of monocytes toward the endothelium through an IL-1-dependent mechanism, which may play an important role in facilitating wound-healing and inflammation processes.

Chemotactic cytokine receptor 5 (CCR5) gene promoter polymorphism (59029A/G) is associated with diabetic nephropathy in Japanese patients with type 2 diabetes: a 10-year longitudinal study

We previously showed that polymorphisms of the promoter area of chemokine receptor 5 (CCR5) gene (59029G/A) and its agonist, regulated upon activation, normal T-cell expressed and secreted (RANTES) gene (-28C/G) were new candidates for susceptibility to diabetic nephropathy. The aim of this study was to confirm the effect of these polymorphisms on the development and progression of diabetic nephropathy. We performed a 10-year retrospective study of 191 Japanese type 2 diabetic patients with normoalbuminuria at baseline. The subjects were classified into two groups: (1) those with persistent normoalbuminuria (group N) and (2) those with progression from normoalbuminuria to microalbuminuria or overt proteinuria (group P). Then, their association with CCR5 59029G/A and RANTES -28C/G polymorphisms was assessed. The frequency of the RANTES -28G(+) genotype did nor differ between the two groups, but the CCR5 59029A(+) genotype had a significantly higher frequency in group P than in group N (83% versus 71%, p=0.04). By discriminant analysis, only the CCR5 59029A(+) genotype showed an independent positive correlation with the onset or progression of nephropathy (p=0.03, odds ratio=2.41, 95% CI=1.09-5.33). Therefore, the CCR5 59029A(+) genotype seems to be related the etiology of diabetic nephropathy in Japanese type 2 diabetics.

Aldosterone blockade attenuates urinary monocyte chemoattractant protein-1 and oxidative stress in patients with type 2 diabetes complicated by diabetic nephropathy

CONTEXT

Aldosterone causes organic impairment by enhancement of oxidative stress and subsequent induction of proinflammatory cytokines and chemokines.

OBJECTIVE

This study was designed to investigate the effect of spironolactone, an aldosterone blocker, on oxidative stress and the level of urinary monocyte chemoattractant protein (MCP)-1, a cysteine-cysteine chemokine that may contribute to progression of various nephropathies in type 2 diabetic patients with diabetic nephropathy. DESIGN, SETTING, PATIENTS AND OTHER PARTICIPANTS, AND INTERVENTION: The patients were randomly assigned to two groups in which they received either spironolactone (50 mg/d; n = 23) or amlodipine (2.5 mg/d; n = 14).

MAIN OUTCOME MEASURES

Urinary 8-iso-prostaglandin (PG) F2alpha (a marker of oxidative stress), urinary MCP-1, and urinary albumin excretion (UAE) were measured at the start of administration (0 months) and after 3 months in each group. Baseline levels of these variables were also measured in 25 age-matched healthy subjects.

RESULTS

There were significant positive correlations between log(10)-transformed (log) 8-iso-PGF2alpha and log MCP-1 levels in control and diabetic subjects and all subjects combined, but no correlations between log UAE and log 8-iso-PGF2alpha or log MCP-1 were found in any group. Significant decreases in 8-iso-PGF2alpha, MCP-1, and UAE were observed with spironolactone (P = 0.0001, P = 0.0041, and P = 0.0037, respectively), and systolic blood pressure significantly decreased after both spironolactone and amlodipine therapy (P = 0.00011 and P = 0.0051, respectively).

CONCLUSIONS

Our data suggest that urinary MCP-1 is correlated with oxidative stress as measured by urinary 8-iso-PGF2alpha and that spironolactone can decrease urinary MCP-1 and oxidative stress.