In vitro investigation of the effects of Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 exopolysaccharides on tight junction damage caused by influenza virus infection

It is a problem that influenza virus infection increases susceptibility to secondary bacterial infection in lungs leading to lethal pneumonia. We previously reported that exopolysaccharides (EPS) derived from Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 (OLL1073R-1) could prevent against influenza virus infection followed by secondary bacterial infection in vitro. Therefore, the present study assessed whether EPS derived OLL1073R-1 protects the alveolar epithelial barrier disfunction caused by influenza virus infection. After A549 cells treated with EPS or without EPS were infected influenza virus A/Puerto Rico/8/34 (IFV) for 12 h, the levels of tight junction genes expression and inflammatory genes expression were measured by reverse transcription polymerase chain reaction. As results, EPS treatment could protect against low-titer IFV infection, but not high-titer IFV infection, followed by suppression of the increased expression of inflammatory cytokine gene levels and recovery of the decrease in the expression level of ZO-1 gene that was caused by low-titer IFV infection, leading to an improvement trend in the barrier function. Our findings showed that EPS derived from OLL1073R-1 could inhibit low-titer IFV infection leading to maintenance of the epithelial barrier function through the suppression of inflammatory cytokine genes expression.

Exploring the significance of interleukin-33/ST2 axis in minimal change disease

Minimal change disease (MCD), a common cause of idiopathic nephrotic syndrome, has been postulated to exhibit an association with allergic conditions. Recent studies revealed the crucial role of interleukin (IL)-33 in type 2 innate immunity. We hypothesized that development of MCD involves an IL-33-related immune response. We examined 49 patients with biopsy-proven MCD, 6 healthy volunteers, and 29 patients in remission. In addition to clinical features, serum and urinary levels of IL-33 and soluble suppression of tumorigenicity 2 protein (sST2), a secreted form of the receptor of IL-33, were analyzed. Although IL-33 was barely detectable in either MCD or control samples, sST2 levels at diagnosis were elevated in MCD patients. Serum sST2 levels of MCD patients were correlated with serum total protein level (r =  - 0.36, p = 0.010) and serum creatinine level (r = 0.34, p = 0.016). Furthermore, the elevated sST2 levels were observed to decrease following remission. Immunofluorescence revealed IL-33 expression in the podocytes among MCD patients, with a significant increase compared with controls. In vitro, mouse podocyte cells incubated with serum from a MCD patient at disease onset showed increased IL-33 secretion. These results suggest an IL-33-related immune response plays a role in MCD.

The essential role of intestinal microbiota in cytomegalovirus reactivation

Human cytomegalovirus (HCMV) is a member of Herpesviridae. It has been reported that HCMV is reactivated in the breast milk of HCMV-seropositive lactating women. As we have reported various aspects of the roles of indigenous microbiota, its role in the murine CMV (MCMV) reactivation was examined in this study. MCMV was latently infected in the salivary gland, mammary tissues, and colon in the pregnant mice. When the salivary gland, mammary tissues, and colon were removed 5 days after delivery, MCMV reactivation of latent infection in each organ was confirmed by the detection of MCMV IE1 mRNA using reverse transcription-quantitative PCR. MCMV reactivation was observed in 100% of the mice during pregnancy. Next, for the elimination of intestinal microbiota, the pregnant mice were treated with low-dose or high-dose non-absorbable antibiotics. Although the numbers of aerobe/anaerobe in cecal content in low-dose antibiotic-treated mice were comparable to those in untreated controls, high-dose antibiotic treatment decreased the number of aerobe/anaerobe microbes from ca.9.0 Log10 to ca.3.0 Log10 (cfu/g). However, it could not be confirmed in 16S rRNA analysis that specific bacterial phylum or genus was eliminated by this high-dose treatment. Interestingly, MCMV reactivation was also observed in 100% of low-dose antibiotic-treated mice, whereas, in high-dose antibiotic-treated mice, MCMV reactivation was not observed in the salivary gland or colon. MCMV IE1 mRNA was detected only in 33% of the mammary tissues of those high-dose-treated mice. These results suggest that the indigenous microbiota played a crucial role in the reactivation of latent infection. IMPORTANCE Human cytomegalovirus (HCMV) infection via breast milk is a serious problem for very preterm infants such as developing a sepsis-like syndrome, cholestasis, or bronchopulmonary dysplasia, among others. It has been reported that HCMV is reactivated in the breast milk of HCMV-seropositive lactating women. In this study, the roles of indigenous microbiota in the murine CMV (MCMV) reactivation were examined using a mouse model. In MCMV latently infected mice, MCMV reactivation was observed in 100% of the mice during pregnancy. For the elimination of intestinal microbiota, MCMV-latent mice were treated with non-absorbable antibiotics. After delivery, MCMV reactivation was not observed in antibiotic-treated mice. This result suggested that the indigenous microbiota played a crucial role in the reactivation of latent infection.

Effects of NKT Cells on Metabolic Disorders Caused by High-Fat Diet Using CD1d-Knockout Mice

Purpose

The purpose of this study was to investigate whether NKT cells play an important role in preventing or exacerbating diseases caused by high-fat diet (HFD) using CD1d-knockout (KO) mice which lack NKT cells.

Methods

Five-week-old male Balb/c (wild-type; WT) or CD1dKO mice were fed with control-diet (CTD) or HFD for 16 weeks.

Results

The present study revealed four main findings. First, CD1dKO mice were susceptible to obesity caused by HFD in comparison to WT mice. Second, clinical conditions of fatty liver caused by HFD were comparable between CD1dKO mice and WT mice. Third, HFD-fed WT mice showed high levels of serum biochemical markers, involved in lipid metabolisms, in comparison to WT mice fed a CTD. Notably, the serum concentrations of ALT, T-CHO, TG and HDL-C in CD1dKO mice fed a HFD were almost comparable to those of CD1dKO mice fed a CTD. Fourth, the expression of peroxisome proliferator-activated receptor (PPAR) γ, low-density lipoprotein receptor (LDLR), CD36 of epididymal adipose tissue enhanced and proprotein convertase subtilisin/kexin type (PCSK) 9 in serum decreased.

Conclusion

NKT cells were responsible for protection against HFD-induced obesity. However, CD1dKO mice were resistant to serum biochemical marker abnormalities after HFD feeding. One possible explanation is that the epididymal adipose tissue of CD1dKO mice could take up greater amounts of excess lipids in serum in comparison to WT mice.

Effect of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibition on Podocytes in Mouse Nephrotic Syndrome

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is known to play a crucial role in dyslipidemia, and an increase in serum PCSK9 levels has also been reported in patients with nephrotic syndrome (NS). However, the specific effects of PCSK9 in kidney disease and the therapeutic potential of targeting PCSK9 in NS remain elusive. We thus investigated the effects of evolocumab (EVO) in mice with adriamycin (ADR)-induced NS. Male BALB/c mice were divided into the following 4 groups: Control, N = 11; EVO (monoclonal antibody for PCSK9), N = 11; ADR, N = 11; and ADR+EVO, N = 11. We also performed in vitro experiments using immortalized murine podocyte cells to validate the direct effects of PCSK9 on podocytes. EVO decreased urinary albumin levels and ameliorated podocytopathy in mice with ADR nephropathy. Further, EVO suppressed the Nod-like receptor protein 3 (NLRP3) inflammasome pathway in podocytes. PCSK9 expression upregulated CD36, a scavenger receptor of oxidized low-density lipoprotein (Ox-LDL), which in turn stimulated the absorption of Ox-LDL in vitro. EVO downregulated CD36 expression in podocytes both in vitro and in vivo. Immunofluorescence staining analysis reveals that CD36 and PCSK9 colocalized in the glomerular tufts of mice with ADR nephropathy. In the patients with focal segmental glomerulosclerosis, the CD36+ area in glomerular tufts increased compared with those diagnosed with minor glomerular abnormalities. This study revealed that EVO ameliorated mouse ADR nephropathy through the regulation of CD36 and NLRP3 inflammasome signaling. EVO treatment represents a potential therapeutic strategy for human NS.

HIF-PHD inhibitor regulates the function of group2 innate lymphoid cells and polarization of M2 macrophages

Hypoxia-inducible factor-prolyl hydroxylase (HIF-PHD) inhibitors are therapeutic agents for renal anemia that work through HIF2-mediated upregulation of erythropoietin (EPO) and have also been reported to suppress renal fibrosis. Group 2 innate lymphoid cells (ILC2s) have been proven to be involved in the pathogenesis of fibrosis in various organs, including the kidney. However, the relationship between the HIF pathway, renal fibrosis, and kidney ILC2s remains unclear. In the present study, we found that HIF activation by HIF-PHD inhibitors suppressed type 2 cytokine production from kidney ILC2s. The enhanced HIF pathway downregulated the IL-33 receptor ST2L on ILC2s, and phosphorylation of downstream p38 MAPK was attenuated. M2 macrophages that promote renal fibrosis were polarized by ILC2 supernatants, but reduced cytokine production from ILC2s treated with HIF-PHD inhibitors suppressed this polarization. Our findings suggest that HIF-PHD inhibitors are potential therapeutic agents for renal fibrosis that are mediated by the alteration of ILC2 function.

Serum Uromodulin Levels Reflect Severity of Clinicopathological Findings in Early Stage IgA Nephropathy

INTRODUCTION

Uromodulin (UMOD), also known as Tamm-Horsfall protein, is a kidney-specific protein. Recently, low levels of urinary UMOD (uUMOD) have been reported as a risk factor for renal function decline in IgA nephropathy (IgAN). However, the clinical significance of serum UMOD (sUMOD) is not clear. In this study, we clarified the clinical significance of sUMOD in IgAN.

METHODS

One hundred eight biopsy-proven IgAN patients were included in this study. The relationships between sUMOD levels and various clinicopathological findings were evaluated.

RESULTS

sUMOD was positively correlated with estimated glomerular filtration rate (eGFR) (p < 0.001, r = 0.5) and negatively correlated with creatinine (Cr) (p < 0.0001, r = -0.51) and urinary protein (UP) (p = 0.005, r = -0.33). In the low sUMOD group (<145 ng/mL), Cr was significantly higher (p < 0.0001) and histopathological changes were severe. The cumulative incidence of a 30% decline in eGFR was 25.6% overall, 0% in histological grade (H-G) I, 33.3% in H-G II, 59.6% in H-G III, and 66.7% in H-G IV. In univariate analyses, prognostic factors for a 30% decline in eGFR were male, high UP, low albumin, low eGFR, and low sUMOD. When comparing the severe histopathological classes (H-G II-IV) and H-G I, low sUMOD was a risk factor for severe histopathological changes. Furthermore, in patients with eGFR > 60 (n = 74), multivariate analyses revealed that low sUMOD independently predicted a 30% decline in eGFR and having severe histopathological changes.

CONCLUSION

In IgAN, sUMOD levels were associated with renal function. Low sUMOD levels may be a risk factor for worsening renal function, especially in the early stage of IgAN.

IL-33 attenuates renal fibrosis via group2 innate lymphoid cells

Renal fibrosis is a common pathway in the progression of various kidney diseases and injuries. Unilateral ureteral obstruction (UUO) induces renal fibrosis, and immune responses profoundly affect its pathogenesis. Group2 innate lymphoid cells (ILC2s) are strongly activated by interleukin (IL) -33, which is a member of IL-1 family and recognize as alarmin. ILC2s quickly produce large amounts of type 2 cytokines including IL-5 and IL-13, which are involved in inflammation, tissue homeostasis, and wound healing. However, the relationship between renal fibrosis and ILC2s has been unclear. In the present study, we investigated the roles of the ILC2/L-33 axis in renal fibrosis using a UUO model. We found that kidney ILC2s decreased in UUO-affected kidneys compared with their counterpart kidneys despite IL-33 upregulation. There was no effect of reactive oxygen species or TGF-β from reduced ILC2 caused by UUO. Pretreatment with IL-33 before UUO induced ILC2s and Tregs in kidneys and alleviated renal fibrosis. Furthermore, this protective effect was maintained even when CD4⁺T cells was depleted. These findings demonstrated that ILC2s play a predominant role in the suppressive function of renal fibrosis mediated by pretreatment with IL-33. In contrast, post-treatment with IL-33 after UUO increased ILC2s in kidneys but had no therapeutic effect on renal fibrosis. Our findings suggest that ILC2s have potential roles in the prevention of renal fibrosis and can serve as a therapeutic and diagnostic target.

Reliability of an Ion-Selective Electrode as a Simple Diagnostic Tool for Mastitis

BACKGROUND

Developing a simple quantitative tool for mastitis diagnosis is essential. The Ion-Selective Electrode for sodium has been reported to reliably measure sodium concentrations in human milk.

RESEARCH AIM

To determine whether an Ion-Selective Electrode measurement of sodium:potassium ratios could serve as a diagnostic tool for mastitis and, if so, to determine the diagnostic cut-off value.

METHODS

A total of 107 milk samples, including 55 from milk bank donors and 52 from participants with mastitis, were studied. The sodium:potassium ratios were determined in 33 samples (without mastitis n = 15; with mastitis n = 18) by the Ion-Selective Electrode and ion chromatography. The remaining 74 samples (donor milk n = 40; participants with mastitis n = 34) were analyzed by Ion-Selective Electrode only. Values were averaged over three measurements for each method.

RESULTS

The median postpartum months of donors and participants with mastitis were 2 and 3 months, respectively. The mean (SD) sodium:potassium ratios without and with mastitis were 0.5 (0.1) and 1.7 (1.2), respectively. A positive correlation existed between sodium:potassium ratios obtained from the two methods (r = 0.98). Area under the curve values were 0.951 (95% CI [0.904, 0.986]) for the Ion-Selective Electrode (N = 107) and 0.978 (95% CI [0.926, 1.000]) for the ion chromatography (n = 33) methods. The optimal cut-off value for the Ion-Selective Electrode method was 0.60, with 86.5% sensitivity and 92.7% specificity.

CONCLUSIONS

The Ion-Selective Electrode was sufficiently accurate for the diagnosis of mastitis. Cohort studies are needed to explore the relationship between sodium:potassium ratios and clinical outcomes.

A case of acute poststreptococcal glomerulonephritis complicated by interstitial nephritis related to streptococcal pyrogenic exotoxin B

This paper presents the case of a patient who developed acute kidney injury and nephrotic syndrome following streptococcal cutaneous infection. He presented with microhematuria, severe proteinuria and systemic edema 5 days after infection. Blood examination showed elevated creatinine level, hypocomplementemia, and elevated anti-streptolysin O level. Renal biopsy revealed endocapillary proliferative glomerulonephritis with tubulointerstitial nephritis (TIN). Immunofluorescence revealed C3-dominant glomerular staining, while electron microscopy showed hump-shaped subepithelial deposits. The patient was therefore diagnosed with poststreptococcal glomerulonephritis. The unique histological feature was C3 deposition in the tubular basement membrane (TBM), in which we detected streptococcal pyrogenic exotoxin B (SpeB), a nephritogenic antigen produced by streptococci. No nephritis-associated plasmin receptor or plasmin activity was evident in the TBM. These nephritogenic antigens and upregulation of plasmin activity were observed in glomeruli. This case suggests that TIN after poststreptococcal infection might be partially attributable to SpeB toxicity.

Exopolysaccharides from Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 prevent influenza virus infection and attenuate secondary bacterial infection risk

The present study assessed the inhibitory action of exopolysaccharides (EPS) produced by Lactobacillus delbrueckii spp. bulgaricus OLL1073R-1 against influenza virus infection followed by secondary bacterial infection. We found that the presence of 200 or 400 μg ml^-1 of EPS significantly protected against influenza virus infection in a dose-dependent manner when A549 cells were treated with EPS before infection but not after it. The expression of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1), an adhesion molecule for bacteria adherence, on A549 cells was significantly enhanced during influenza virus infection compared to viral-non-infected A549 cells. However, this upregulated CEACAM-1 expression was significantly decreased by EPS treatment before viral infection in association with the reduction in the virus titer in A549 cells. In a bacterial adhesion assay using Staphylococcus aureus, the bacterial adherence to viral-infected A549 cells was significantly greater than that to viral-non-infected A549 cells, and the increased bacterial adherence induced by influenza virus infection tended to be decreased by EPS treatment before the infection. Our findings show that EPS treatment before viral infection can inhibit influenza virus infection and alleviate secondary bacterial infection through decreased CEACAM-1 expression.

The Roles of Kidney-Resident ILC2 in Renal Inflammation and Fibrosis

Innate lymphoid cells (ILCs) are a recently discovered lymphocyte population with high cytokine productive capacity. Type-2 ILCs (ILC2s) are the most studied, and they exert a rapid type-2 immune response to eliminate helminth infections. Massive and sustainable ILC2 activation induces allergic tissue inflammation, so it is important to maintain correct ILC2 activity for immune homeostasis. The ILC2-activating cytokine IL-33 is released from epithelial cells upon tissue damage, and it is upregulated in various kidney disease mouse models and in kidney disease patients. Various kidney diseases eventually lead to renal fibrosis, which is a common pathway leading to end-stage renal disease and is a chronic kidney disease symptom. The progression of renal fibrosis is affected by the innate immune system, including renal-resident ILC2s; however, the roles of ILC2s in renal fibrosis are not well understood. In this review, we summarize renal ILC2 function and characterization in various kidney diseases and highlight the known and potential contributions of ILC2s to kidney fibrosis.

Reno-protective effect of IL-34 inhibition on cisplatin-induced nephrotoxicity in mice

INTRODUCTION

Interleukin-34 (IL-34) shares a receptor (cFMS) with colony stimulating factor-1 (CSF-1), and these two ligands mediate macrophage proliferation. However, in contrast to CSF-1, the influence of IL-34 on tubular epithelial cells (TECs) injury remains unclear. We investigated the physiological effects of IL-34 on TEC damage caused by cisplatin nephrotoxicity (CP-N).

METHODS

Mice were administered anti-mouse IL-34 antibody (anti-IL-34 Ab; 400 ng/kg) or vehicle from 1 day before and up to 2 days after CP-N induction. In vitro, mouse renal proximal TECs (MRPTEpiC) were cultured to analyze the inhibitory effects of IL-34 on CP-induced TEC apoptosis.

RESULTS

Compared to vehicle treatment, anti-IL-34 Ab treatment significantly suppressed the intra-renal expression of IL-34 and its two receptors, cFMS and PTP-ζ, and significantly improved renal function, ameliorated tubulointerstitial injury, suppressed macrophage infiltration, and reduced apoptotic cell numbers in CP-N mice. It also significantly reduced the renal transcript levels of Kim-1, MIP-1/CCL3, TNF-α, and Bax in CP-N mice. Furthermore, anti-IL-34 Ab-treated CP-N mice showed less renal infiltration of F4/80+TNF-α+ cells. In vitro, stimulation with CP induced the expression of IL-34 and its two receptors in MRPTEpiC. Anti-IL-34 Ab treatment significantly suppressed CP-induced Bax expression with the degradation of ERK1/2 phosphorylation in damaged MRPTEpiC.

CONCLUSIONS

IL-34 secreted from damaged TECs appeared to be involved in the progression of CP-N. Inhibition of IL-34 with neutralizing antibody directly prevented CP-induced TEC apoptosis by inhibiting the phosphorylation of ERK 1/2. Blocking of IL-34 appears to suppress the proliferation of cytotoxic macrophages, which indirectly attenuates CP-N. Thus, IL-34 represents a potential therapeutic target for TEC injury, and the inhibition of IL-34 might have a reno-protective effect.

Oral administration of trehangelin-A alleviates metabolic disorders caused by a high-fat diet through improvement of lipid metabolism and restored beneficial microbiota

The present study investigated whether or not the oral administration of trehangelin-A (THG-A) is effective for metabolic disorders caused by a high-fat diet, as we previously showed that the intraperitoneal administration of THG-A improved metabolic disorders caused by a high-fat diet. Mice received a control diet or high-fat diet for eight weeks. Concurrently, mice were orally administered 0.2 ml/mouse phosphate-buffered saline (PBS) or 1 or 10 mg/0.2 ml/mouse of THG-A once daily during the experiment. The weight gain caused by a high-fat diet was significantly suppressed by oral THG-A compared to a high-fat diet without THG-A. In addition, at eight weeks after starting the diet, the increased plasma total-cholesterol (T-CHO) and low-density lipoprotein-cholesterol (LDL-C) levels caused by a high-fat diet were significantly reduced by 10 mg/mouse THG-A and tended to attenuated by 1 mg/mouse THG-A. The LDL receptor and CYP7A1 mRNA expression in liver associated with lipid metabolism for reducing plasma LDL-C levels was significantly enhanced by oral THG-A. In contrast, oral THG-A exerted no marked effects on mice fed the control diet. The dysbiosis of a high-fat diet fed mice, which is in the form of an increased Firmicutes-to-Bacteroidetes ratio, also recovered, and the high-fat diet induced decreased levels of Bacteroides and Akkermansia genera, which are beneficial microbiota against metabolic disorders, were also restored by oral THG-A. These results indicate that oral THG-A administration acts on metabolic disorders by improving the lipid metabolism and restoring beneficial microbiota to resolve high-fat diet induced dysbiosis.

P0528RENOPROTECTIVE EFFECT OF IL-34 INHIBITION ON CISPLATIN-INDUCED NEPHROTOXICITY IN MICE

Background and Aims

Interleukin (IL)-34, a macrophage (Mø) mediator, is expressed by tubular epithelial cells (TECs). However, the influence of IL-34 on TECs injury has not been fully elucidated. We investigated the physiological properties of IL-34 on TECs damage caused by cisplatin-nephrotoxicity (CP-N).

Method

7-week-old male C57BL/6 (B6) mice (n=16) were fasted for 8 hours and then induced CP-N by intraperitoneal injection (IP) of CP (25 mg/kg) on day 0. Groups of animals were given either anti-mouse IL-34 antibody (CP+anti-IL-34 Ab, 400 ng/kg, n=8) or vehicle (CP+V, equal volume of saline, n=8) daily by IP from day -1 to day 2. Three age-matched male B6 mice were used as normal control (NC). All mice were sacrificed on day 3. In addition, mouse renal proximal TECs (MRTEpiC) were cultured to analyze the inhibitory effects of IL-34 on CP-induced TEC apoptosis. Cells were stimulated with CP (2 μg/mL), then treated with or without anti-IL-34 Ab (1000 pg/mL).

Results

Compared to the NC, CP+V mice exhibited marked acute kidney injury (AKI) and upregulated expression of IL-34 and its two receptors, cFMS and PTP-ζ. Compared to the vehicle treatment, anti-IL-34 Ab treatment significantly suppressed the intrarenal expression levels of IL-34 and its two receptors in CP-N mice; it also significantly suppressed serum IL-34 levels (72.1 ± 5.6 vs. 40.4 ± 7.5 pg/mL, p=0.013). Additionally, treatment with anti-IL-34 Ab significantly improved serum Cr levels (1.3 ± 0.2 vs. 0.7 ± 0.1 mg/mL, p=0.033), ameliorated tubulointerstitial injury (numbers of casts/HPF: 11.9 ± 2.6 vs. 6.5 ± 1.8, p=0.048), and suppressed the number of F4/80+ Mø (17.5 ± 2.7 vs. 11.1 ± 1.1/HPF, p=0.041) and TUNEL+ apoptotic cells (29.2 ± 4.9 vs. 16.7 ± 2.7/HPF, p=0.036) in CP-N mice. The renal cortical transcript levels of Kim-1, MIP-1/CCL3, TNF-α, and Bax were significantly lower in the CP+anti-IL-34 Ab mice than in the CP+V mice. Furthermore, the CP+anti-IL-34 Ab mice showed significantly less renal infiltration of CD11b+F4/80+TNF-α+ cells. In vitro, stimulation with CP induced the expression of IL-34 and its two receptors in MRTEpiC. Treatment with anti-IL-34 Ab significantly suppressed CP-induced caspase-3 and Bax expression with degradation of ERK1/2 phosphorylation in the damaged MRTEpiC.

Conclusion

IL-34 secreted from damaged TECs was involved in the progression of CP-N. Inhibition of IL-34 with neutralizing antibody directly prevented CP-induced TEC apoptosis by inhibiting the phosphorylation of ERK1/2. Blocking of IL-34 might suppressed proliferation of cytotoxic Mø, which indirectly led to the attenuation of CP-N. Thus, IL-34 represents a potential as therapeutic target for AKI with TECs injury.

SO076EVOLOCUMAB HAS THERAPEUTIC EFFECTS ON EXPERIMENTAL MODEL OF FSGS

Background and Aims

Proprotein convertase subtilisin/kexin type 9 (PCSK9), which accelerates LDL-receptor degradation, plays a central role in dyslipidemia in nephrotic syndrome (NS). Intracellular LDL-C accumulation is supposed to damage podocytes through oxidative stress, foam cell formation, and apoptosis. In the present study, we investigate the effects of evolocumab (EVO), which is anti-PCSK9 monoclonal antibody, on a murine model of adriamycin-induced focal segmental glomerulosclerosis (FSGS) with NS in order to clarify the potential of EVO as a therapeutic agent in FSGS.

Method

Male BALB/c mice aged 9 to 11 weeks were divided into vehicle and intervention groups. The mice underwent subcutaneous injection of normal saline (FSGS-Vehicle group) or EVO (30 mg/kg) (FSGS-EVO group) and immediately after that, they were administered adriamycin (11.5 mg/kg) from tail vein. All mice were sacrificed on Day 14, and then morphological and functional analyses were performed.

Results

EVO treatment significantly reduced serum levels of LDL-C (mg/dl, 305.3±77.1 vs. 159.1±31.7, p&lt;0.01) and PCSK9 (ng/ml, 652.9±230.0 vs 311±116.5, p&lt;0.001). In addition, EVO treatment significantly improved renal function, including albuminuria (albumin/creatinine (Cr), 15.73±1.26 vs. 7.32±1.02, p&lt;0.001), serum Cr (mg/dl, 0.48±0.13 vs. 0.18±0.044, p&lt;0.001) and BUN (mg/dl, 80.08±20.22 vs. 46.86±9.60, p&lt;0.05). Compatibly with the clinical data, the severity of glomerulosclerosis score (semi-quantification, 2.44 vs. 1.95, p&lt;0.001) was ameliorated and podocyte density (number of podocyte/glomerulus, 2.61 vs. 7.54, p&lt;0.001) was maintained in the FSGS-EVO mice compared with the FSGS-Vehicle mice.

Conclusion

Our findings provided novel insights into the protective effects of EVO on adriamycin nephropathy, indicating EVO as a potent therapeutic agent for FSGS.

A cross-sectional analysis of clinicopathologic similarities and differences between Henoch-Schönlein purpura nephritis and IgA nephropathy

Introduction

Recent studies noted that Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) share the feature of galactose-deficient IgA1 (Gd-IgA1)-oriented pathogenesis, although there are distinct clinical differences. We aimed to clarify the clinicopathologic differences between these 2 diseases.

Methods

We cross-sectionally analyzed adult patients with HSPN (n = 24) or IgAN (n = 56) who underwent renal biopsy (RB) between 2008 and 2018 at Showa University Hospital. Serum Gd-IgA1 (s-Gd-IgA1) levels at the time of RB were compared among study groups using enzyme-linked immunosorbent assay (ELISA) with anti-human Gd-IgA1-specific monoclonal antibody (KM55). We also immunohistochemically stained paraffin-embedded sections for glomerular Gd-IgA1 (g-Gd-IgA1)-deposition using KM55. Serum inflammatory cytokines were measured using ELISA.

Results

Glomerular endothelial injury with subendothelial IgA deposition was significant in patients with HSPN. Serum IL-8, MCP-1, TNF-α, and IL-6 levels were significantly higher in patients with HSPN than IgAN. Levels of s-Gd-IgA1 were comparable among patients with HSPN and IgAN, and a similar degree of g-Gd-IgA1-deposition was detected in both diseases. Furthermore, g-Gd-IgA1-deposition was evident in patients with histopathologically advanced HSPN or IgAN. In HSPN, significant positive correlations between s-Gd-IgA1 levels and crescent formation or IL-6 elevation were confirmed, and g-Gd-IgA1 intensity showed a significant positive correlation with MCP-1 and a tendency to positively correlate with IL-8. Meanwhile, patients with IgAN showed no correlation between inflammatory cytokines and both-Gd-IgA1. Moreover, most g-Gd-IgA1-positive areas were not double stained with CD31 in HSPN.

Conclusions

Although assessing both-Gd-IgA1 alone was insufficient to distinguish between HSPN and IgAN, patients with HSPN showed considerable glomerular capillaritis with subendothelial IgA deposition and significant elevation of serum inflammatory cytokines. Furthermore, such glomerular subendothelial IgA deposition might not contain Gd-IgA1, and factors associated with Gd-IgA1 were inconsistent among these 2 diseases. Thus, developmental mechanisms for IgAN might not apply to HSPN completely, and these 2 diseases still have different aspects.

Recombinant human soluble thrombomodulin attenuates anti-glomerular basement membrane glomerulonephritis in Wistar-Kyoto rats through anti-inflammatory effects

BACKGROUND

Since recombinant human soluble thrombomodulin (RH-TM) has anti-inflammatory properties through neutralizing high-mobility group box 1 protein (HMGB1), the protective effects of RH-TM were examined in anti-glomerular basement membrane (GBM) glomerulonephritis (GN) in Wistar-Kyoto rats.

METHODS

Rats were injected with nephrotoxic serum (NTS) to induce anti-GBM GN on Day 0, and were given either RH-TM or vehicle from Day 0 to Day 6. Rats were sacrificed 7 days after NTS injection.

RESULTS

RH-TM-treated rats had decreased proteinuria and serum creatinine level. RH-TM significantly reduced the percentage of glomeruli with crescentic features and fibrinoid necrosis. In addition, RH-TM-treated rats had significantly reduced glomerular ED1+ macrophage accumulation as well as reduced renal cortical proinflammatory cytokine expression. Furthermore, RH-TM had a potent effect in reducing intercellular adhesion molecule-1 (ICAM-1) expression in kidneys and urine. RH-TM significantly reduced renal cortical mRNA levels for toll-like receptor -2 and -4, known as receptors for HMGB1, and their downstream adopter protein, myeloid differentiation primary respond protein 88 (MyD88).

CONCLUSIONS

We showed for the first time that anti-inflammatory effects, which were characterized by reduced glomerular macrophage influx concomitant with a marked reduction in proinflammatory cytokines, were involved in the mechanism of attenuating experimental anti-GBM GN by RH-TM. The observed effects might be attributable to the downregulation of ICAM-1 by reducing the HMGB1/TLR/MyD88 signaling pathway.

Therapeutic Potential of Thrombomodulin in Renal Fibrosis of Nephrotoxic Serum Nephritis in Wistar-Kyoto Rats

BACKGROUND

Recombinant human soluble thrombomodulin (rhTM) was approved in 2008 and has been used for treatment of disseminated intravascular coagulation in Japan. The antifibrotic effects of rhTM in acute exacerbation of idiopathic pulmonary fibrosis are well established, but the therapeutic potential of rhTM in renal fibrosis remains poorly understood.

METHODS

Nephrotoxic serum nephritis (NTS-N) was induced in 22 female Wistar-Kyoto (WKY) rats on day 0. Rats were administered either rhTM or vehicle intraperitoneally, every day from day 4 to day 55. Rats were sacrificed on day 56 when renal fibrosis was established and renal morphological investigations were performed. In vitro, rat renal fibroblasts (NRK-49F) were pretreated with rhTM or saline, and expression levels of profibrogenic gene induced by thrombin were analyzed by real-time reverse transcription polymerase chain reaction.

RESULTS

Compared to WKY-GN-vehicle rats, the body weights of WKY-GN-rhTM rats were significantly greater on day 55. By day 56, rhTM had significantly reduced serum creatinine levels in NTS-N. On the other hand, urinary protein excretion was comparable between the two treatment groups throughout the study. The percentage of Masson trichrome-positive areas in WKY-GN-rhTM rats was significantly lower compared to that in WKY-GN-vehicle rats. Glomerular fibrin deposition was significantly reduced in WKY-GN-rhTM rats. In addition, rhTM significantly reduced the renal cortical mRNA expression levels of TNF-α, Toll-like receptor 4, MYD88, TGF-β, αSMA, collagen I, collagen III, fibronectin, and protease-activated receptor 1 (PAR1), a thrombin receptor. In vitro, thrombin stimulation of NRK-49F cells significantly enhanced the mRNA expression levels of αSMA and PAR1, and these upregulations were significantly reduced by pretreatment with rhTM.

CONCLUSIONS

Administration of rhTM after establishment of crescentic glomerulonephritis (GN) attenuated the subsequent development of renal fibrosis in NTS-N, possibly in part by inhibiting thrombin-mediated fibrogenesis. Our results suggest that rhTM may offer a therapeutic option for limiting the progression of chronic kidney disease in crescentic GN.

Serum uromodulin is associated with the severity of clinicopathological findings in ANCA-associated glomerulonephritis

Background

Uromodulin (UMOD), also known as Tamm-Horsfall protein, is a kidney-specific protein expressed by epithelial cells lining the thick ascending limb of the loop of Henle. In the current study, we aimed to clarify the clinical significance of UMOD in ANCA-associated glomerulonephritis (AAG).

Materials and methods

Sixty-one biopsy-proven AAG patients were included in this study. UMOD was measured using ELISA. The relationships between serum UMOD (sUMOD) levels and various clinicopathological findings were evaluated.

Results

AAG was classified into four categories (focal, crescentic, mixed, and sclerotic). In addition, tubulointerstitial lesions were classified as mild, moderate, and severe. The levels of sUMOD and urinary UMOD (uUMOD) were correlated with each other. A negative correlation between sUMOD levels and serum Cr levels, and positive correlation between sUMOD levels and eGFR were found. Patients in the high sUMOD group were associated with low serum Cr levels, focal classification, and mild tubulointerstitial injury compared to the low sUMOD group. Comparing the characteristics among histopathological classes, patients in the focal class had the best renal function and the highest levels of uUMOD/Cr and sUMOD. The focal class had significantly better renal survival compared with the severe histopathological classes (crescentic, mixed, and sclerotic). In univariate logistic regression analyses, prognostic factors for severe histopathological classes were low uUMOD/Cr, high serum Cr, and low sUMOD. Multivariate analyses revealed that low sUMOD predicted severe histopathological classes independent of serum Cr. The mean levels of sUMOD were significantly different between the focal class and severe histopathological classes, with a sensitivity of 70.6% and specificity of 90.0% (cut-off 143 ng/ml, AUC 0.80) by ROC curves.

Conclusion

Low sUMOD levels were associated with severe clinicopathological findings and might be considered as a risk factor for end stage renal disease in AAG.

Erlotinib attenuates the progression of chronic kidney disease in rats with remnant kidney

Background

Increasing evidence indicates that epidermal growth factor receptor (EGFR) has a pathogenic role in renal fibrosis. Currently no effective treatment can completely halt the progression of chronic kidney disease (CKD). This study was undertaken to investigate the renoprotective effects of erlotinib, a tyrosine kinase inhibitor that can block EGFR activity in the progression of CKD and the mechanisms involved.

Methods

Sprague Dawley rats with 5/6 nephrectomy were administered either erlotinib or vehicle from 2 weeks after surgery and for a period of 8 weeks. Blood pressure, proteinuria and serum creatinine were measured periodically. Renal morphological investigations were performed at sacrifice. In vitro, we used normal human mesangial cells (NHMCs) and human proximal tubular cells to investigate the inhibitory effects of erlotinib on renal fibrosis-associated signaling pathways by western blotting.

Results

Erlotinib treatment significantly blunted the progression of CKD as evidenced by reduced levels of serum creatinine, proteinuria and renal cortical profibrogenic genes and scores of glomerulosclerosis and tubulointerstitial damage. Tubulointerstitial macrophage infiltration and multiple pro-inflammatory cytokine gene expression levels were also attenuated by erlotinib treatment. In vitro, heparin-binding epidermal growth factor-like growth factor-induced Akt and extracellular-regulated kinase (ERK) 1/2 activation in normal human mesangial cells and human proximal tubular cells was inhibited by pretreatment with erlotinib.

Conclusions

EGFR blocking by erlotinib protected against renal fibrosis in 5/6 nephrectomized rats via inhibition of Akt and ERK 1/2 signaling pathways, which are associated with renal fibrosis. Erlotinib also has anti-inflammatory properties, which may contribute to its renoprotective effects. Erlotinib represents a potential novel therapeutic strategy for the treatment of CKD.

Elimination of intravenous alendronate by hemodialysis: A kinetic study

INTRODUCTION

The potential utility of intravenous alendronate for the treatment of osteoporosis in hemodialysis patients was recently reported. However, the pharmacokinetics of intravenous alendronate in patients on hemodialysis is not clear.

METHODS

Six hemodialysis patients (mean age, 80.5 years) with osteoporosis who had received intravenous alendronate prior to the study were enrolled. The participants received a 30-min infusion of 900-μg alendronate intravenously at the beginning of the dialysis session. The blood flow rate (Qb) and dialysate flow rate (Qd) were set at 200 mL/min and 500 mL/min, respectively. All patients used the same dialyzer (1.5-m² polysulfone membrane). At the completion of administration, plasma and dialysate samples were collected, and alendronate concentrations were determined using metal-free high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS).

RESULTS

The plasma arterial alendronate concentration was 150.9 ± 46.09 ng/mL. It decreased through the dialyzer to 76.1 ± 34.1 ng/mL (venous alendronate concentration). Mean alendronate clearance was 113.9 ± 25.6 mL/min. Mean alendronate removal by hemodialysis, measured by the difference in arterial-venous concentrations, was 51.8%.

CONCLUSIONS

Fifty percent of intravenous alendronate was removed by hemodialysis, which is nearly equal to elimination of alendronate in patients with normal renal function. The elimination by hemodialysis would decrease the risk of excessive accumulation in bone. UMIN 000027182.

Effects of Denosumab and Alendronate on Bone Health and Vascular Function in Hemodialysis Patients: A Randomized, Controlled Trial

Mineral and bone disorders including osteoporosis are common in dialysis patients and contribute to increased morbimortality. However, whether denosumab and alendronate are effective and safe treatments in hemodialysis patients is not known. Thus, we conducted a prospective, three-center study of 48 hemodialysis patients who were diagnosed as having osteoporosis and had not received anti-osteoporotic agents previously. Participants were randomized to either denosumab or intravenous alendronate, and all subjects received elemental calcium and calcitriol during the initial 2 weeks. The primary endpoint was the percent change in lumbar spine bone mineral density (LSBMD) at 12 months of treatment. The secondary endpoints included the following: change in BMD at other sites; change of serum bone turnover markers (BTM), coronary artery calcium score (CACS), ankle-brachial pressure index (ABI), brachial-ankle pulse wave velocity (baPWV), flow mediated dilation (FMD), and intima-media thickness at the carotid artery (CA-IMT); change from day 0 to day 14 in serum levels of Ca and P; time course of serum calcium (Ca), phosphorus (P), and intact parathyroid hormone (i-PTH); new fractures; and adverse events. Initial supplementation with elemental calcium and calcitriol markedly ameliorated the decrease of serum corrected calcium (cCa) levels induced by denosumab during the first 2 weeks, whereas serum cCa levels in the alendronate group were increased. Denosumab and alendronate markedly decreased serum levels of BTM and increased LSBMD at 12 months compared with baseline. However, no significant differences were found in the changes in LSBMD between the two groups. The serum cCa, P, and i-PTH levels in the two groups were maintained within the appropriate range. In contrast to the anti-osteoporotic effects, no significant differences after 12 months of treatment were found in the CACS, CA-IMT, ABI, baPWV, and FMD compared with pretreatment in both groups. Denosumab and alendronate treatment improved LSBMD, reduced BTM, and appeared to be safe in hemodialysis patients with osteoporosis. © 2019 American Society for Bone and Mineral Research.

Membranous nephropathy caused by rheumatoid arthritis

Membranous nephropathy (MN) caused by disease-modifying antirheumatic drugs is relatively common in patients with rheumatoid arthritis (RA). However, MN rarely occurs due to RA itself. We describe a 61-year-old woman with RA who showed nephrotic syndrome. She was admitted because of systemic edema and severe arthritis. She had a long history of RA successfully treated with methotrexate (MTX), but discontinued all treatments 4 years before hospitalization. She had never been treated with bucillamine or gold. Laboratory test results were positive for anti-cyclic citrullinated peptide antibody and negative for anti-nuclear antibody. Renal pathologic findings were compatible with MN. Immunofluorescence microscopy showed IgG, IgA, κ, λ, and C3 along the glomerular capillary wall, whereas deposition of IgM or C1q was not detected. In terms of the IgG subclasses, only IgG2 findings were positive. Results for glomerular antigen and serum antibody for M-type phospholipase A2 receptor and thrombospondin type 1 domain-containing 7A were negative. HLA type did not include the HLA-DQA1 gene that is a concern in primary MN (PMN). She responded to intensive immunosuppressive therapy consisting of prednisolone, tacrolimus, and MTX with a parallel reduction of proteinuria. Based on assessments for differentiating PMN from secondary MN (SMN), the diagnosis of the present case was incompatible with PMN. Taken together, we consider that SMN in the present case was due to RA itself rather than drug-induced MN.

Clinical significance of serum and mesangial galactose-deficient IgA1 in patients with IgA nephropathy

Introduction

Galactose-deficient IgA1 (Gd-IgA1) is a critical pathogenic factor for IgA nephropathy (IgAN), but its value as a disease-specific biomarker remains controversial. We aimed to clarify the clinical significance of Gd-IgA1 in patients with IgAN.

Methods

We retrospectively reviewed 111 patients who were diagnosed with IgAN based on the findings of renal biopsies (RB) at Showa University Hospital since 2007. Serum Gd-IgA1 (s-Gd-IgA1) at the time of RB was compared among 111 IgAN patients, 18 Henoch-Schönlein purpura nephritis (HSPN) patients, 29 lupus nephritis (LN) patients, 28 ANCA-associated vasculitis (AAV) patients, and 13 minimal change disease (MCD) patients using ELISA with an anti-human Gd-IgA1-specific monoclonal antibody (KM55). We also immunohistochemically stained paraffin-embedded sections for mesangial Gd-IgA1 (m-Gd-IgA1) deposition using KM55.

Results

Although levels of s-Gd-IgA1 were comparable among IgAN and HSPN, s-Gd-IgA1 levels were significantly elevated in patients with IgAN compared with LN, AAV and MCD (IgAN vs. HSPN, LN, AAV, and MCD: 16.2 ± 9.1 vs. 14.2 ± 10.8, p = 0.263; 12.7 ± 9.4, p = 0.008; 13.1 ± 7.3, p = 0.059; and 8.2 ± 4.8 μg/mL, p<0.001, respectively). Mesangial-Gd-IgA1 deposition was specifically detected in IgAN or HSPN. The increase in s-Gd-IgA1 significantly correlated with m-Gd-IgA1 positivity in patients with IgAN, and s-Gd-IgA1 elevation and m-Gd-IgA1 deposition were evident in patients with histopathologically advanced IgAN. Moreover, s-Gd-IgA1 levels were significantly higher in IgAN patients with glomerular sclerosis and tubulo-interstitial lesions. Mesangial-Gd-IgA1 intensity negatively correlated with eGFR in IgAN. Multivariate analysis selected s-Gd-IgA1 elevation as a significant risk factor for a 30%-reduction in eGFR in IgAN (HR, 1.37; 95% CI, 1.02–1.89; p = 0.038).

Conclusions

Although IgAN and HSPN remain difficult to differentiate, s-Gd-IgA1 elevation and m-Gd-IgA1 deposition are reliable diagnostic factors that reflect IgAN severity. Serum-Gd-IgA1 could serve as a predictor of renal outcomes in IgAN. Thus, Gd-IgA1 could be significant biomarker for patients with IgAN.

The effects of denosumab and alendronate on glucocorticoid-induced osteoporosis in patients with glomerular disease: A randomized, controlled trial

INTRODUCTION

The clinical utility of denosumab for the treatment of glucocorticoid-induced osteoporosis (GIOP) has yet to be established. This study aimed to compare the effects of denosumab on bone mineral density (BMD) and bone turnover markers to those of alendronate in patients with GIOP.

METHODS

A prospective, single-center study of 32 patients (18 men; median age, 66.0 years) with glomerular disease receiving prednisolone (PSL) who were diagnosed as having GIOP and had not received bisphosphonates before was conducted. Participants were randomized to either alendronate (35 mg orally once a week) or denosumab (60 mg subcutaneously once every 6 months), and all subjects received calcitriol. The primary endpoint was the percent change in lumbar spine (LS) BMD at 12 months of treatment.

RESULTS

The demographic and clinical characteristics at baseline were not significantly different between the groups. Denosumab treatment markedly decreased serum levels of t-PINP, BAP, and TRACP-5b at 12 months compared to baseline (-57.4%, p<0.001; -30.9%, p<0.01; -57.7%, p<0.001, respectively). After 12 months of alendronate treatment, serum levels of t-PINP, BAP, and TRACP-5b were also significantly decreased compared to pretreatment (-38.9%, p<0.01; -16.3%, p<0.05; -43.5%, p<0.01, respectively). However, no significant differences in the changes of bone turnover markers were found between the two groups. As for the effects on BMD, denosumab treatment markedly increased LS BMD from 6 months compared to baseline, whereas no significant difference compared to pretreatment was found in the alendronate group during the study period. In the comparison of the two groups, a large increase of LS BMD was found in the denosumab treatment group compared to the alendronate treatment group at 12 months (p<0.05).

CONCLUSIONS

In patients with GIOP, denosumab treatment markedly suppressed bone turnover, which led to a significantly greater increase in LS BMD than with alendronate treatment. These results suggest that denosumab is a therapeutic option for the treatment of GIOP.

Rituximab for the treatment of type B insulin resistance syndrome: a case report and review of the literature

BACKGROUND

Type B insulin resistance syndrome is a rare disease characterized by refractory transient hyperglycaemia and severe insulin resistance associated with circulating anti-insulin receptor antibodies. A standardized treatment regimen for type B insulin resistance syndrome has yet to be established.

CASE REPORT

We report the case of a 64-year-old man undergoing haemodialysis for antineutrophil cytoplasmic antibody-associated vasculitis and diabetic nephropathy, who developed rapid onset of hyperglycaemia (glycated albumin 52.1%). Type B insulin resistance syndrome was diagnosed, on the basis of positivity for anti-insulin receptor antibodies and the man's autoimmune history of antineutrophil cytoplasmic antibody-associated vasculitis and idiopathic thrombocytopenic purpura. Although severe hyperglycaemia persisted in spite of corticosteroids and high-dose insulin therapy, rituximab treatment resulted in remarkable improvement of the man's severe insulin resistance and disappearance of anti-insulin receptor antibodies without any adverse effects.

CONCLUSIONS

According to a literature review of 11 cases in addition to the present case, rituximab appears to be a safe and effective strategy for the treatment of corticosteroid-resistant type B insulin resistance syndrome.

Combination Therapy of Denosumab and Calcitriol for a Renal Transplant Recipient with Severe Bone Loss due to Therapy-Resistant Hyperparathyroidism

Denosumab (DMAb), a complete human type monoclonal antibody directed against the receptor activator of nuclear factor-κB ligand, has gained attention as a novel treatment for osteoporosis. However, its efficacy in patients with chronic kidney disease (CKD) remains unclear. We describe a 64-year-old man with severe bone loss and persistent secondary hyperparathyroidism (SHPT) after renal transplantation, whose condition failed to respond to conventional pharmacologic or surgical interventions. He underwent parathyroidectomy with left forearm autograft of crushed tiny parathyroid gland (PTG) particles. However, the autografted PTGs became swollen and caused persistent SHPT in spite of two additional parathyroidectomies of the left forearm. A single subcutaneous administration of DMAb induced hypocalcemia, which was corrected by calcium supplementation and high-dose calcitriol. Eventually, combination therapy with DMAb and calcitriol led to a decline in the patient's elevated serum parathyroid hormone levels, normalization of laboratory markers of bone metabolism, and improvement in bone mineral density in a short period of time. To the best of our knowledge, this is the first case report of severe bone loss with persistent SHPT in a renal transplant recipient effectively treated with the combination therapy of DMAb and vitamin D (VD). Although DMAb itself exerts no direct effects on PTGs, the DMAb treatment improved the patient's bone loss. In addition, administration of DMAb allowed for high-dose VD therapy which ultimately controlled SHPT and prevented DMAb-induced hypocalcemia. Therefore, this combination therapy might be a reasonable therapeutic strategy to reverse severe bone loss due to therapy-resistant SHPT in patients with CKD.

Anti-Phospholipase A2 Receptor (PLA2R) Antibody and Glomerular PLA2R Expression in Japanese Patients with Membranous Nephropathy

The phospholipase A2 receptor (PLA2R) is the major target antigen (Ag) in idiopathic membranous nephropathy (IMN). Recently, several types of immunoassay systems for anti-PLA2R antibody (Ab) have been developed. However, the correlation of serum anti-PLA2R Abs and glomerular expression of PLA2R Ag, and their association with clinicopathological characteristics have yet to be proven in Japanese patients. We examined serum anti-PLA2R Abs by both ELISA and cell-based indirect immunofluorescence assay (CIIFA), and glomerular PLA2R expression by immunofluorescence (IF) in 59 biopsy-proven MN patients including IMN (n = 38) and secondary MN (SMN) (n = 21). In this study, anti-PLA2R Abs were present in 50% of IMN patients, but was absent in SMN patients. The concordance rate between ELISA and CIIFA was 100%. Serum IgG levels were significantly lower in anti-PLA2R Ab-positive patients. Serum albumin levels correlated inversely with serum anti-PLA2R Ab titers. The prevalence and intensity of glomerular staining for IgG4 by IF were significantly higher in anti-PLA2R Ab-positive patients than in -negative patients. Glomerular PLA2 Ag expression evaluated by IF was positive in 52.6% of IMN patients, but was absent in SMN patients. The concordance rate between the prevalence of glomerular PLA2R Ag expression and anti-PLA2R Ab was 84.2%. The prevalence of anti-PLA2R Abs measured by ELISA/CIIFA was equivalent to previous Japanese studies evaluated using Western blotting. These analyses showed an excellent specificity for the diagnosis of IMN, and anti-PLA2R positivity was associated with some clinicopathological features, especially glomerular IgG4-dominant deposition.

Therapeutic effects and mechanism of conditioned media from human mesenchymal stem cells on anti-GBM glomerulonephritis in WKY rats

Recent studies have demonstrated that conditioned media derived from mesenchymal stem cells (MSC-CM) have therapeutic effects in various experimental diseases. However, the therapeutic mechanism is not fully understood. In the present study, we investigated the therapeutic effects and mechanism of MSC-CM in experimental antiglomerular basement membrane glomerulonephritis. We administered either MSC-CM or vehicle from day 0 to day 10 after the induction of nephrotoxic serum nephritis in Wistar-Kyoto rats. In vitro, we analyzed the effects of MSC-CM on TNF-α-mediated cytokine production in cultured normal human mesangial cells, proximal tubular (HK-2) cells, human umbilical vein endothelial cells, and monocytes (THP-1 and peripheral blood mononuclear cells). Compared with vehicle treatment, MSC-CM treatment improved proteinuria and renal dysfunction. Histologically, MSC-CM-treated rats had reduced crescent formation and glomerular ED1+ macrophage infiltration and increased glomerular ED2+ macrophage infiltration. Increased serum monocyte chemoattractant protein (MCP)-1 levels were observed in MSC-CM-treated rats. Renal cortical mRNA expression levels of proinflammatory cytokines, such as TNF-α and IL-6, and of the T helper cell 1 cytokine interferon-γ were greatly decreased by MSC-CM treatment. In vitro, pretreatment with MSC-CM blocked TNF-α-mediated IL-8 release in normal human mesangial cells and HK-2 cells. TNF-α-mediated MCP-1 release was enhanced by pretreatment with MSC-CM in human umbilical vein endothelial cells and HK-2 cells and was strikingly enhanced in THP-1 cells. Stimulation of peripheral blood mononuclear cells with a combination of MCP-1 and IL-4 enhanced the expression of M2-associated genes compared with IL-4 alone. We demonstrated that MSC-CM had therapeutic effects in experimental antiglomerular basement membrane glomerulonephritis that were mediated through anti-inflammatory effects that were partly due to acceleration of M2 macrophage polarization, which might be mediated by MCP-1 enhancement.

A Novel Mutation in a Japanese Family with X-linked Alport Syndrome

We herein report a novel mutation in a Japanese family with an X-linked Alport syndrome (AS) mutation in COL4A5. Patient 1 was a 2-year-old Japanese girl. She and her mother (patient 2) had a history of proteinuria and hematuria without renal dysfunction, deafness, or ocular abnormalities. Pathological findings were consistent with AS, and a genetic analysis revealed that both patients had a heterozygous mutation (c.2767G>C) in exon 32. In summary, the identification of mutations and characteristic pathological findings was useful in making a diagnosis of AS. For a close long-term follow-up, the early detection and treatment of women with X-linked AS are important.

Streptococcal Infection-related Nephritis (SIRN) Manifesting Membranoproliferative Glomerulonephritis Type I

We herein report the case of an 18-year-old boy who developed nephrotic syndrome and hypertension after upper airway inflammation. Post-streptococcal acute glomerulonephritis was diagnosed on the basis of a high antistreptolysin O titer, hypocomplementemia, proteinuria, and microscopic hematuria. A renal biopsy was performed due to persistent proteinuria, and the pathological diagnosis was membranoproliferative glomerulonephritis (MPGN) type I. Glomeruli showed positive staining for nephritis-associated plasmin receptor (NAPlr), a nephritogenic group A streptococcal antigen, and plasmin activity was found in a similar distribution as NAPlr deposition. This rare case of streptococcal infection-related nephritis (SIRN) manifesting MPGN type I supports the histological diversity of SIRN.

A case of sporadic medullary cystic kidney disease type 1 (MCKD1) with kidney enlargement complicated by IgA nephropathy

Medullary cystic kidney disease (MCKD) is a progressive tubulointerstitial nephropathy, and it leads to end-stage kidney disease (ESKD). It is an autosomal dominant inherited disease, and is categorized into two types according to the localizing chromosome and timing of ESKD onset. Its pathogenesis has not been revealed clearly, thus accumulation of the cases is very valuable. We report here the first reported case of MCKD with kidney enlargement complicated by IgA nephropathy. A 70-year-old male was admitted to our hospital because of renal dysfunction and bilateral kidney enlargement. He was diagnosed as having MCKD complicated by IgA nephropathy (IgA-N) by renal biopsy. We speculated that he had MCKD type 1 on the basis of the late onset of renal failure and no significant evidence of mutation in the UMOD gene that is associated with MCKD type 2. Thereafter, his kidney function decreased progressively and he started to receive hemodialysis. This is an interesting case of MCKD1 in terms of its sporadic nature, kidney enlargement, and complication of IgA-N.

Light-Chain Deposition Disease Successfully Treated with Bortezomib in an Elderly Patient: A Case Report and Review of the Literature

We herein report the case of an elderly patient with light-chain deposition disease (LCDD) successfully treated with bortezomib. An 83-year-old woman was admitted because of nephrotic syndrome. She was diagnosed to have monoclonal gammopathy of undetermined significance (IgG-κ type) and LCDD, on the basis of serum and urinary immunoelectrophoresis and renal biopsy. She responded to a modified regimen of bortezomib-based chemotherapy with disappearance of proteinuria without any adverse effects. According to a literature review of 16 cases, including the present case, bortezomib-based chemotherapy appears to be a convincing strategy for the treatment of LCDD even in elderly patients.

Epidermal growth factor receptor inhibition with erlotinib partially prevents cisplatin-induced nephrotoxicity in rats

The effects of blocking the epidermal growth factor receptor (EGFR) in acute kidney injury (AKI) are controversial. Here we investigated the renoprotective effect of erlotinib, a selective tyrosine kinase inhibitor that can block EGFR activity, on cisplatin (CP)-induced AKI. Groups of animals were given either erlotinib or vehicle from one day before up to Day 3 following induction of CP-nephrotoxicity (CP-N). In addition, we analyzed the effects of erlotinib on signaling pathways involved in CP-N by using human renal proximal tubular cells (HK-2). Compared to controls, rats treated with erlotinib exhibited significant improvement of renal function and attenuation of tubulointerstitial injury, and reduced the number of apoptotic and proliferating cells. Erlotinib-treated rats had a significant reduction of renal cortical mRNA for profibrogenic genes. The Bax/Bcl-2 mRNA and protein ratios were significantly reduced by erlotinib treatment. In vitro, we observed that erlotinib significantly reduced the phosphorylation of MEK1 and Akt, processes that were induced by CP in HK-2. Taken together, these data indicate that erlotinib has renoprotective properties that are likely mediated through decreases in the apoptosis and proliferation of tubular cells, effects that reflect inhibition of downstream signaling pathways of EGFR. These results suggest that erlotinib may be useful for preventing AKI in patients receiving CP chemotherapy.