[Show abstract][Hide abstract] ABSTRACT: Introduction and Aims: IgA nephropathy, the most common primary glomerulonephritis worldwide, can lead to end-stage renal disease and kidney transplantation. Disease recurrence frequently occurs after transplantation. We investigated the predictive value of three markers including galactose-deficient (Gd) IgA1, IgG anti-IgA autoantibodies, IgA-soluble (s) CD89 complexes for IgA nephropathy recurrence. The efficacy of intravenous pulse steroid administration for treatment of recurrent IgA nephropathy was evaluated.Methods: The IgA nephropathy recurrent group (R group, n=11) was compared to matched patients transplanted for IgA nephropathy but without recurrence (NR group, n=13) and healthy subjects (n=22) for proportions of serum Gd-IgA1, IgA-IgG complexes and IgA-sCD89 complexes. Efficacy of pulse steroid therapy in reducing proteinuria was analysed in kidney transplant recipients R group.Results: Pre-transplantation serum proportion of Gd-IgA1 and IgA-IgG complexes were higher in R group compared to NR g
Full-text · Article · May 2014 · Nephrology Dialysis Transplantation
[Show abstract][Hide abstract] ABSTRACT: Focal and segmental glomerulosclerosis (FSGS) is one of the most important renal diseases related to end stage renal failure. Bradykinin has been implicated in the pathogenesis of renal inflammation whereas the role of its receptor 2 (B2RBK) in FSGS has not been studied. FSGS was induced in wild type and B2RBK KO mice by a single intravenous injection of Adriamycin (ADM). In order to further modulate the kinin receptors, animals were also treated with B2RBK antagonist HOE-140, and DALBK, B1RBK antagonist. Here, we show that the blockage of B2RBK with HOE-140 protects mice from FSGS development, including podocyte foot process effacement and reestablishment of slit diaphragm-related proteins. However, B2RBK KO mice were not protected from FSGS. These opposite results were due to B1RBK expression. B1RBK was up regulated after ADM injection and it was exacerbated in B2RBK KO animals. Further, HOE-140 treatment down regulated B1RBK receptor. The blockade of B1RBK in B2RBK KO animals promoted FSGS regression, with a less inflammatory phenotype. These results indicate a deleterious role of both kinin receptors in FSGS model and suggest a possible crosstalk of them in disease progression.
[Show abstract][Hide abstract] ABSTRACT: To study the correlation between fungal colonization and bacterial pneumonia and to test the effect of antifungal treatments on the development of bacterial pneumonia in colonized rats.
Experimental animal investigation.
University research laboratory.
Pathogen-free male Wistar rats weighing 250-275 g.
Rats were colonized by intratracheal instillation of Candida albicans. Fungal clearance from the lungs and immune response were measured. Both colonized and noncolonized animals were secondarily instilled with different bacterial species (Pseudomonas aeruginosa, Escherichia coli, or Staphylococcus aureus). Bacterial phagocytosis by alveolar macrophages was evaluated in the presence of interferon-gamma, the main cytokine produced during fungal colonization. The effect of antifungal treatments on fungal colonization and its immune response were assessed. The prevalence of P. aeruginosa pneumonia was compared in antifungal treated and control colonized rats.
C. albicans was slowly cleared and induced a Th1-Th17 immune response with very high interferon-gamma concentrations. Airway fungal colonization favored the development of bacterial pneumonia. Interferon-gamma was able to inhibit the phagocytosis of unopsonized bacteria by alveolar macrophages. Antifungal treatment decreased airway fungal colonization, lung interferon-gamma levels and, consequently, the prevalence of subsequent bacterial pneumonia.
C. albicans airway colonization elicited a Th1-Th17 immune response that favored the development of bacterial pneumonia via the inhibition of bacterial phagocytosis by alveolar macrophages. Antifungal treatment decreased the risk of bacterial pneumonia in colonized rats.
Full-text · Article · Jul 2013 · Critical care medicine
[Show abstract][Hide abstract] ABSTRACT: Acute pyelonephritis (APN), which is mainly caused by uropathogenic Escherichia coli (UPEC), is the most common bacterial complication in renal transplant recipients receiving immunosuppressive treatment. However, it remains unclear how immunosuppressive drugs, such as the calcineurin inhibitor cyclosporine A (CsA), decrease renal resistance to UPEC. Here, we investigated the effects of CsA in host defense against UPEC in an experimental model of APN. We show that CsA-treated mice exhibit impaired production of the chemoattractant chemokines CXCL2 and CXCL1, decreased intrarenal recruitment of neutrophils, and greater susceptibility to UPEC than vehicle-treated mice. Strikingly, renal expression of Toll-like receptor 4 (Tlr4) and nucleotide-binding oligomerization domain 1 (Nod1), neutrophil migration capacity, and phagocytic killing of E. coli were significantly reduced in CsA-treated mice. CsA inhibited lipopolysaccharide (LPS)-induced, Tlr4-mediated production of CXCL2 by epithelial collecting duct cells. In addition, CsA markedly inhibited Nod1 expression in neutrophils, macrophages, and renal dendritic cells. CsA, acting through inhibition of the nuclear factor of activated T-cells (NFATs), also markedly downregulated Nod1 in neutrophils and macrophages. Silencing the NFATc1 isoform mRNA, similar to CsA, downregulated Nod1 expression in macrophages, and administration of the 11R-VIVIT peptide inhibitor of NFATs to mice also reduced neutrophil bacterial phagocytosis and renal resistance to UPEC. Conversely, synthetic Nod1 stimulating agonists given to CsA-treated mice significantly increased renal resistance to UPEC. Renal transplant recipients receiving CsA exhibited similar decrease in NOD1 expression and neutrophil phagocytosis of E. coli. The findings suggest that such mechanism of NFATc1-dependent inhibition of Nod1-mediated innate immune response together with the decrease in Tlr4-mediated production of chemoattractant chemokines caused by CsA may contribute to sensitizing kidney grafts to APN.
[Show abstract][Hide abstract] ABSTRACT: Background & aims:
Lipopolysaccharide (LPS)-expressing bacteria cause severe inflammation in cirrhotic patients. The global gene response to LPS is unknown in cirrhotic immune cells.
Gene-expression profiling using Affymetrix Human Exon Array analyzed the expression of 14,851 genes in LPS-stimulated peripheral blood mononuclear cells (PBMCs) from 4 patients with cirrhosis and 4 healthy subjects. We performed validation studies using RT-qPCR in LPS-stimulated PBMCs from 52 patients and 9 healthy subjects and investigated the association of gene induction with mortality in 26 patients.
Gene-expression profiling of LPS-stimulated cirrhotic cells showed 509 upregulated genes and 1588 downregulated genes. In LPS-stimulated "healthy" cells, 952 genes were upregulated and 838 genes downregulated. The 741 LPS-regulated genes shared by cirrhotic and "healthy" cells were involved in cytokine production/activity and induction of "immune paralysis". Comparison of functions associated with the 1356 genes, specifically regulated by LPS in cirrhotic cells, to functions of the 1049 genes, specifically regulated in "healthy" cells, allowed to define a cirrhosis-specific phenotype. Unlike in "healthy" cells, LPS failed to induce an interferon-mediated program in cirrhotic cells. In cirrhotic PBMCs, LPS specifically induced certain molecules involved in apoptosis and downregulated molecules involved in endocytic trafficking. RT-qPCR experiments showed that LPS-stimulated cirrhotic PBMCs had an enhanced induction of certain proinflammatory cytokines and chemokines. In the prognosis study, higher ex vivo LPS-induction of the inflammatory genes IL6 and CXCL5 was a significant predictor of mortality.
Our results show that LPS-stimulated cirrhotic PBMCs exhibit an extensive and often unexpected transcriptional response.
No preview · Article · Jan 2013 · Journal of Hepatology
[Show abstract][Hide abstract] ABSTRACT: Introduction and Aims: Pauci-immune necrotizing glomerulonephritis (PINGN) with antineutrophil cytoplasmic autoantibody (ANCA) are observed in systemic
vasculitis (Microscopic polyangiitis [MPA] with or without granuloma) but can be isolated and considered as vasculitis limited
to the kidney. By immunofluorescence, very few immmunoglobulin deposits can be observed associated with some C3 deposits.
Recent studies in murine models indicate that complement alternative pathway is involved in the development of necrotizing
glomerulonephritis. We seeked to analyse the deposition of complement activation products in kidney biopsies of PINGN, using
immunohistochemistry (IHC) and immunofluorescence (IF) staining.
Methods: Renal biopsies from 11 patients with PR3-ANCA and 8 patients with MPO-ANCA (5 MPA without granuloma, 3 isolated PINGN) were
studied with anti-C3d (IHC), anti-C4d (IHC) and anti-C5b-9 (IF) antibodies and compared to C3c deposits observed with standard
IF in glomeruli. Control biopsies were 2 cases of PINGN without C3c deposits, 1 case of acute post infectious glomerulonephritis
with C3c granular deposits, and one normal kidney biopsy.
Results: 10 of 11 renal biopsies from patients with PR3-ANCA had a moderate segmental or diffuse granular C3d staining in 38,5% of
glomeruli, with identical localisation compared to C3c deposits. A C4d staining was noted in the same localization as C3d
but with milder intensity and in only 4 cases. C5b-9 studied in the 10 cases with IF available showed a moderate to intense
granular deposit in the flocculus (along glomerular basement membrane in 1 case). The 8 renal biopsies from patients with
MPO-ANCA had a strong granular C3d staining in 57% of glomeruli. As for PR3-ANCA biopsies, C4d was positive only in 5 of 8
renal biopsies. C5b-9 staining was positive in the 4 cases tested with IF available. The C5b-9 staining was similar in the
two groups, but in the MPO group, some segmental accumulation was observed in segmental lesions corresponding to crescents
and necrosis. In control biopsies, C5b-9 was absent in glomerulus floculus of normal kidney but had identical distribution
in acute post infectious glomerulonephritis.
Conclusions: Complement pathways activation products, including those of the classical alternative pathway, are detected in the glomeruli
of patients with PINGN. We have observed a more intense staining of C3d in patients with MPO-ANCA compared to patients with
PR3-ANCA, which may reflect the more chronic/subacute course of MPO-PINGN compared to PR3-PIGN.
Full-text · Article · May 2012 · Nephrology Dialysis Transplantation
[Show abstract][Hide abstract] ABSTRACT: Kidney International aims to inform the renal researcher and practicing nephrologists on all aspects of renal research. Clinical and basic renal research, commentaries, The Renal Consult, Nephrology sans Frontieres, minireviews, reviews, Nephrology Images, Journal Club. Published weekly online and twice a month in print.
Preview · Article · Sep 2011 · Kidney International
[Show abstract][Hide abstract] ABSTRACT: INTRODUCTION AND AIMS: The development of vascular calcification (VC) in elderly patients generates significantly increased cardiovascular risk.
In patients with chronic kidney disease (CKD) the VC process occurs much more rapidly. Matrix-Gla protein (MGP) is a vitamin-K
dependent protein that inhibits calcification. Warfarin, a common therapy used in dialysis patients, attenuates the activity
of MGP by blocking the formation of vitamin K. In the present study we sought to determine whether a therapeutic warfarin
treatment accelerated the rate of VC in a rat model of CKD.
METHODS: Sprague Dawley rats were fed a diet containing either 0.25% adenine (CKD) or 0% adenine (control), both diets containing
high phosphate (1%) and low vitamin K (0.2 mg/kg). Warfarin (0.1 mg/kg body weight/day) was administered in the drinking water
of CKD (n=8) and control (n=8) animals. After 7 weeks on the diet, rats were anesthetized and fluid filled catheters inserted
into the carotid artery were used to measure blood pressure using PowerLab data aquisition system (ADInstruments, Colarado,
USA). Kidney function was assessed by measuring serum creatinine and urea. INR values were assessed using INRatio 2 (HemoSense,
San Diego, CA, USA). VC was assessed using the calcium-O-cresophthalein assay.
RESULTS: Creatinine levels were significantly elevated in the CKD group (345 ± 117 µmol/L) compared to controls (51 ± 10 µmol/L).
Serum phosphate levels were also elevated in CKD animals (4.8 ± 2.8 mM) compared to controls (1.9 ± 0.4 mM) and linearly correlated
with creatinine (r2=0.73, p<0.0001). INR levels were elevated from 1.3 ± 0.2 in controls to 3.3 ± 0.8 in warfarin treated animals. The calcium
content was analyzed in the thoracic aorta, abdominal aorta, renal artery and carotid artery. The average calcium content
in all these vessels was significantly elevated in warfarin treated CKD animals (445 ± 576 nmol/mg tissue) compared to untreated
CKD animals (33 ± 59 nmol/mg tissue) and control animals with no CKD (6 ± 1.8 nmol/mg tissue). Pulse pressure in CKD animals
with VC was significantly elevated compared to animals with no VC (p<0.01).
CONCLUSIONS: Taken together, these results indicate that therapeutic warfarin treatment in a rat model of CKD accelerates the development
of VC. Further studies are necessary to elucidate potential treatment targets to prevent this calcification process and evaluate
the safety of potential alternative anticoagulation therapies in CKD. (Funds: KFOC, KM:CIHR, NS:CIHR).
No preview · Article · Jun 2011 · CKJ: Clinical Kidney Journal
[Show abstract][Hide abstract] ABSTRACT: Finding two or more genotypes of a single species within an infected sample is a not infrequent event. In this work, three Escherichia coli strains of decreasing extra-intestinal virulence (pathogenic B2S and B1S strains, and the avirulent K-12 MG1655 strain) were tested in septicaemia and urinary tract infection (UTI) mouse models, either separately or in pairs. Survival was monitored and bacteria were counted in various organs. Serum interleukin (IL)-6, tumour necrosis factor alpha (TNFα) and IL-10 were measured. We show that a mix of high amounts of B1S or of MG1655 with low amounts of B2S killed more rapidly (B1S), or killed more mice (MG1655), than either high amounts of B1S, high amounts of MG1655 or low amounts of B2S separately in the mouse septicaemia model. This bacterial synergy persisted when high amounts of dead or abnormal-LPS K-12 cells were injected together with a low amount of B2S. In both septicaemia and UTI models, significantly more bacteria were recovered from the organs of mice injected with the MG1655/B2S mix than from those of mice injected with the inocula separately. Consistently, in the septicaemia model, more IL-6 was secreted before death by the mice that were injected with the mix of bacteria than by the mice that were injected with the inocula separately. The synergistically enhanced mortality in the case of co-infection in the septicaemia model persisted in RFcγ(-/-), Myd88(-/-) and IL-6(-/-) knockout mice. This synergistically increased virulence resulting from the interaction between an avirulent and a pathogenic strain of the same bacterial species raises questions about the role of avirulent bacteria in the development of some extra-intestinal infections.
[Show abstract][Hide abstract] ABSTRACT: Allergic asthma is a chronic lung disease resulting from an inappropriate T helper (Th)-2 response to environmental antigens. Early tolerance induction is an attractive approach for primary prevention of asthma. Here, we found that breastfeeding by antigen-sensitized mothers exposed to antigen aerosols during lactation induced a robust and long-lasting antigen-specific protection from asthma. Protection was more profound and persistent than the one induced by antigen-exposed non-sensitized mothers. Milk from antigen-exposed sensitized mothers contained antigen-immunoglobulin (Ig) G immune complexes that were transferred to the newborn through the neonatal Fc receptor resulting in the induction of antigen-specific FoxP3(+) CD25(+) regulatory T cells. The induction of oral tolerance by milk immune complexes did not require the presence of transforming growth factor-beta in milk in contrast to tolerance induced by milk-borne free antigen. Furthermore, neither the presence of IgA in milk nor the expression of the inhibitory FcgammaRIIb in the newborn was required for tolerance induction. This study provides new insights on the mechanisms of tolerance induction in neonates and highlights that IgG immune complexes found in breast milk are potent inducers of oral tolerance. These observations may pave the way for the identification of key factors for primary prevention of immune-mediated diseases such as asthma.
[Show abstract][Hide abstract] ABSTRACT: HTLV-I is an endemic retrovirus responsible for the adult T-cell leukemia/lymphoma (ATLL). This aggressive lymphoid proliferation is associated with a bad prognosis due to the resistance of HTLV-I-infected cells to most classical chemotherapeutic agents. Here we review recent advances in ATLL immunotherapy. We particularly focus on promising data from our group, characterizing a new mouse monoclonal antibody (mAb A24) against the human transferrin receptor (TfR-1). Monoclonal antibodies to target cell differentiation markers on ATLL cells have already been proposed as therapeutic agents. However, in clinical trials acute forms of ATLL were resistant to these immunotherapies. A24 binds TfR-1 (K(d) 2.7 nM) and competes with transferrin for receptor binding. It blocks the proliferation of malignant cells (TfR-1(high)), such as HTLV-I-infected T cells but not of resting cells. A24 induces TfR-1 endocytosis in lysosomal compartments where the receptor is degraded leading to intracellular iron deprivation. In HTLV-I-infected cells, A24 targets and induces apoptosis of both chronic and acute ATLL forms, independent of antibody aggregation, antibody-dependent cellular cytotoxicity and/or complement addition. The antibody efficacy was confirmed in animal models. We are currently developing strategies to use A24 in clinical trials.
Full-text · Article · Feb 2008 · Leukemia: official journal of the Leukemia Society of America, Leukemia Research Fund, U.K