Kozue Okumura

Interleukin-12 is involved in the enhancement of human natural killer cell activity by Lactobacillus casei Shirota.

We conducted a placebo‐controlled, cross‐over trial to examine the effect of Lactobacillus casei Shirota (LcS) on natural killer (NK) cell activity in humans. NK cell activity exhibited a declining trend during the period of placebo ingestion, but NK cell activity increased after intake for 3 weeks of fermented milk containing 4 × 1010 live LcS. When human peripheral blood mononuclear cells were cultured in the presence of heat‐killed LcS, NK cell activity was enhanced. The ability of LcS to enhance NK cell activity and induce interleukin (IL)‐12 production was correlated, and the addition of anti‐IL‐12 monoclonal antibody reduced the enhancement of NK cell activity triggered by LcS. In addition, separation of NK cells from LcS‐stimulated monocytes with membrane filter reduced NK cell activity to the intermediate level and almost deprived monocytes of the ability to produce IL‐12. These results demonstrate that LcS can enhance NK cell activity in vivo and in vitro in humans, and IL‐12 may be responsible for enhancement of NK cell activity triggered by LcS.

Serum soluble CD4 and CD8 levels in Kawasaki disease

The levels of soluble CD4 (sCD4) and sCD8 in serum correlate with the T cell subset activation and may be important in monitoring and characterizing disease processes during immunological diseases. We compared acute Kawasaki disease (KD) with anaphylactoid purpura (AP) and acute febrile viral infections, such as measles and infectious mononucleosis (IM), in terms of serum sCD4 and sCD8 levels. The levels of serum sCD4 and sCD8 were measured by a sandwich enzyme immunoassay. In addition, peripheral blood mononuclear cell subsets were analysed by single and two‐colour flow‐cytometric analyses in KD and IM patients. The levels of serum sCD4 and sCD8 were significantly elevated in patients during acute stages of KD, measles and IM, but not AP. Peripheral blood CD4+, CD8+ and also HLA‐DR+ T cells count did not increase during the acute stage of KD; however, peripheral blood CD8+ and HLA‐DR+ T cell counts were increased during the acute stage of IM. Our results suggest that there is a low level of activation of peripheral blood T cells during acute KD, or that infiltrated T cells in some local tissues of KD patients contribute to the elevated levels of serum sCD4 and sCD8.

Risk factors associated with increased left ventricular mass index in chronic kidney disease patients evaluated using echocardiography

BACKGROUND It is still not clear which factors are associated with left ventricular mass index (LVMI) in chronic kidney disease (CKD) patients, based on the patients physical and biochemical parameters at the time of echocardiography. The objective of the present study was to identify factors associated with LVMI in CKD patients (predialysis patients), using echocardiography. METHODS Physical, biochemical and LVMI data evaluated by echocardiography were retrospectively analyzed in 930 CKD patients in Juntendo University Hospital, Tokyo, Japan. RESULTS Levels of systolic blood pressure (SBP) and hemoglobin (Hb) were independent risk factors for increased LVMI in multivariate regression analysis. SBP was significantly correlated with LVMI (r=0.314, p<0.0001). The level of Hb was inversely correlated with LVMI (r=-0.372, p<0.0001). LVMI increased with decreasing renal function. SBP was significantly higher in patients with left ventricular hypertrophy (LVH) in CKD stages 2 and 5, and Hb was significantly lower in patients with LVH in stages 4 and 5 than in the group without LVH. CONCLUSIONS It is important to treat hypertension and anemia to prevent LVH in CKD patients. These findings have some therapeutic implications for treatment strategies for predialysis patients.

Role of tumour necrosis factor‐alpha (TNF‐α) in the induction of HIV‐1 gp120‐mediated CD4+ T cell anergy

The HIV‐1 envelope glycoprotein (gp120) is known to induce antigen‐specific and non‐specific CD4+ T cell anergy. We found that early T cell activation, as indicated by HLA‐DP expression in the early G1 (G1A) phase of the cell cycle, and the inhibition of mitogen‐mediated IL‐2 production induced by gp120, required TNF‐α produced by gp120‐stimulated macrophages. In the presence of an antibody to TNF‐α, these changes induced by gp120 were inhibited, while recombinant TNF‐α induced similar abnormalities of CD4+ T cells, even in the absence of gp120. On the other hand, inhibition of the mixed lymphocyte reaction (MLR) in CD4+ T cells by gp120, which may be related to gp120‐mediated down‐regulation of CD4 expression on T cells and activation of protein tyrosine kinase p56lck in CD4+ T cells, was observed even in the absence of macrophage‐derived TNF‐α induced by gp120. These observations indicate that both TNF‐α‐dependent and independent events contribute to gp120‐mediated CD4+ T cell anergy, and TNF‐α appears to play an important role in inducing CD4+ T cell anergy in HIV‐1 infection.

Monocyte chemoattractant protein (MCP)-1 production via functionally reconstituted Fcα receptor (CD89) on glomerular mesangial cells

AbstractBackground: Fc alpha receptor (FcαR; CD89) is the receptor for Fc portion of IgA in various cells, and displays various immunological responses on binding. It is important to analyze the mesangial functions via FcαR in the pathogenesis of IgA nephropathy. However, it is still controversial whether FcαR is expressed on mesangial cells. To assess biological functions of FcαR on the mesangial cells, we established mesangial transfectants that expressed FcαR with or without FcRγ chain that is a common signaling molecule of FcRs. The production of monocyte chemoattractant protein-1 (MCP-1) by mesangial cells is known to contribute to cellular infiltration into glomeruli and subsequent glomerular injuries. Methods: Murine mesangial cell lines (SV40 MES 13) were transfected with cDNA of the human FcαR. Furthermore, we co-transfected some of the FcαR transfectants with cDNA of human FcRγ chain. The tyrosine phosphorylation of the intra-mesangial proteins after FcαR cross-linking was examined by immunoprecipitation. MCP-1 production from each transfectant stimulated with heat aggregated IgA was determined by sandwich ELISA. Results: Two kinds of mesangial transfectants stably expressed human FcαR with or without FcRγ chain (FcαR+, FcαR+/γ+). Phosphorylation of FcRγ chain and syk kinase was detected in FcαR+ and FcαR+/γ+ cells, but not in untransfected cells. Aggregated IgA induced significantly higher MCP-1 production in FcαR+/γ+ than those in FcαR+ or untransfected control. Conclusions: Present study demonstrated that FcαR and FcRγ chain could be reconstituted in mesangial cells and mediated MCP-1 production by aggregated IgA in a dose-dependent manner. Current data would argue that FcαR can be activated in mesangial cells through their own machinery, although underlying mechanisms for FcαR induction in mesangial cells remain unclear.

Predictive factors associated with left ventricular hypertrophy at baseline and in the follow-up period in non-diabetic hemodialysis patients.

Hemodialysis (HD) patients frequently have an elevated left ventricular mass index (LVMI). Currently, left ventricular (LV) hypertrophy and dysfunction are considered to be the strongest predictors of cardiovascular mortality in dialysis patients. The objectives of the present study are to investigate the factors associated with elevated LVMI and to discuss therapeutic implications for the treatment strategy for pre‐dialysis and HD patients. The correlation among biochemical values, physical specimens, and LVMI using echocardiography was prospectively analyzed in 30 non‐diabetic HD patients in the Juntendo University Hospital. Measurement of these parameters was performed at 0, 12, and 24 months after initiation of HD. Systolic blood pressure (SP), human atrial natriuretic peptide (hANP), and hemoglobin (Hb) levels were significantly correlated with LVMI. SBP, residual glomerular filtration rate (rGFR), and serum albumin levels were identified as independent risk factors for LVMI in multivariate regression analysis at initiation of HD. SBP, hANP, and Hb levels were identified as independent risk factors for LVMI in multivariate regression analysis after 24 months. SBP, rGFR, and serum albumin levels were predictive factors for LVMI at initiation of HD. SBP, hANP, and Hb levels were also predictive factors for LVMI after initiation of HD.

Predictive factors associated with change rates of LV hypertrophy and renal dysfunction in CKD patients

BACKGROUND This longitudinal study is the first report on the factors associated with change rates of the estimated glomerular filtration rate (eGFR) and left ventricular mass index (LVMI) using echocardiography in chronic kidney disease (CKD) patients. METHODS Measurements of biochemical and physical values, and LVMI evaluated by echocardiography were performed twice (baseline and follow-up period) in pre-dialysis CKD patients. Blood and urine samples were collected at the time of the echocardiographic study. RESULTS The change rates of hemoglobin (Hb) and transferrin saturation (TSAT: (serum iron/total iron binding capacity)) were identified as independent risk factors for changes in eGFR by multivariate regression analysis. In the LVMI improvement group, the change rate of systolic blood pressure (sBP) was identified as an independent factor for change in LVMI. In the LVMI worsening group, the change rates of sBP, proteinuria and Hb were identified as independent risk factors for changes in LVMI. CONCLUSIONS It appears that treatment of renal and iron deficiency anemia might prevent progression of renal dysfunction. To prevent LV hypertrophy in CKD patients, renal anemia, hypertension and proteinuria should be treated.

Effects of Acetate-Free Citrate Dialysate on Glycoxidation and Lipid Peroxidation Products in Hemodialysis Patients

Background/Aims: Previous studies have shown the presence of high levels of glycoxidation and lipid peroxidation products in association with atherosclerosis in patients with end-stage kidney disease. Acetates are commonly used buffer for correcting metabolic acidosis in hemodialysis (HD) patients. Since the toxic effects of acetates are well established, acetate-free citrate dialysate (AFD) has become available in Japan. The objective of the present study was to evaluate the suppressive effects of AFD on oxidative stress in maintenance HD patients by measuring plasma pentosidine and malondialdehyde-modified low-density lipoprotein (MDA-LDL) levels as markers for glycoxidation and lipid peroxidation products. Methods: Plasma pentosidine, MDA-LDL and other laboratory parameters were examined on maintenance HD at the Juntendo University Hospital before and after switching to AFD. Results: MDA-LDL levels divided by LDL cholesterol were significantly lower than those before switching to AFD. Furthermore, levels of plasma pentosidine were lower than those before switching to AFD. Stepwise multiple regression analysis revealed that the percent change of the calcium-phosphorus product in the nondiabetic group and that of phosphorus in the diabetic group were predictive variables for the percent change of MDA-LDL/LDL, whereas the percent change of log high-sensitive C-reactive protein and that of systolic blood pressure in the nondiabetic group and that of diastolic blood pressure in the diabetic group were predictive variables for the percent change of plasma pentosidine. Conclusions: It appears that AFD decreases glycoxidation and lipid peroxidation products when compared with acid citrate dextrose in HD patients. The reduction of oxidative stress by AFD during HD may have possible beneficial effects on atherosclerosis through calcium-phosphorus metabolism and blood pressure.

Negative regulation of inflammatory responses by immunoglobulin A receptor (FcαRI) inhibits the development of Toll-like receptor-9 signalling-accelerated glomerulonephritis.

Myeloid FcαRI, a receptor for immunoglobulin (Ig)A, mediates cell activation or inhibition depending on the type of ligand interaction, which can be either multivalent or monovalent. Anti‐inflammatory signalling is triggered by monomeric targeting using anti‐FcαRI Fab or IgA ligand binding, which inhibits immune and non‐immune‐mediated renal inflammation. The participation of Toll‐like receptors (TLRs) in kidney pathology in experimental models and various forms of human glomerular nephritis has been discussed. However, little is known about negative regulation of innate‐immune activation. In the present study, we generated new transgenic mice that express FcαRIR209L/FcRγ chimeric protein and showed that the monovalent targeting of FcαRI exhibited inhibitory effects in an in vivo model of TLR‐9 signalling‐accelerated nephritis. Mouse monoclonal anti‐FcαRI MIP8a Fab improved urinary protein levels and reduced the number of macrophages and immunoglobulin deposition in the glomeruli. Monovalent targeting using MIP8a Fab attenuates the TLR‐9 signalling pathway and is associated with phosphorylation of extracellular signal‐related protein kinases [extracellular signal‐regulated kinase (ERK), P38, c‐Jun N‐terminal kinase (JNK)] and the activation of nuclear factor (NF)‐κB. The inhibitory mechanism involves recruitment of tyrosine phosphatase Src homology 2 domain‐containing phosphatase‐1 (SHP‐1) to FcαRI. Furthermore, cell transfer studies with macrophages pretreated with MIP8a Fab showed that blockade of FcαRI signalling in macrophages prevents the development of TLR‐9 signalling‐accelerated nephritis. These results suggest a role of anti‐FcαRI Fab as a negative regulator in controlling the magnitude of the innate immune response and a new type of anti‐inflammatory drug for treatment of kidney disease.