Association between reduced left ventricular ejection fraction and peritoneal dialysis related peritonitis: a single center retrospective cohort study in Japan.

We present a single-center retrospective analysis of 228 Japanese patients with peritoneal dialysis, in which we examined whether reduced left ventricular ejection fraction (LVEF) is a risk factor for peritonitis development. Time-dependent multivariable-adjusted Cox proportional hazards models revealed that reduced LVEF (LVEF < 50% vs. preserved LVEF ≥ 50%, hazard ratio (HR) 2.10; 95% confidence interval (CI) 1.16-3.82) was associated with peritonitis. Qualitatively, similar associations with reduced LVEF (< 50%) were observed for enteric peritonitis (adjusted HR 7.68; 95% CI 2.51-23.5) but not for non-enteric peritonitis (adjusted HR 1.15; 95% CI 0.54-2.44). Reduced LVEF is associated with a significantly higher risk of subsequent peritonitis, particularly enteric peritonitis. These results indicate that patients with reduced LVEF may be at risk of enteric peritonitis from bowel sources caused by intestinal involvement due to cardiac dysfunction.

Development and Evaluation of a Robust Sandwich Immunoassay System Detecting Serum WFA-Reactive IgA1 for Diagnosis of IgA Nephropathy.

Aberrant glycosylation of IgA1 is involved in the development of IgA nephropathy (IgAN). There are many reports of IgAN markers focusing on the glycoform of IgA1. None have been clinically applied as a routine test. In this study, we established an automated sandwich immunoassay system for detecting aberrant glycosylated IgA1, using Wisteria floribunda agglutinin (WFA) and anti-IgA1 monoclonal antibody. The diagnostic performance as an IgAN marker was evaluated. The usefulness of WFA for immunoassays was investigated by lectin microarray. A reliable standard for quantitative immunoassay measurements was designed by modifying a purified IgA1 substrate. A validation study using multiple serum specimens was performed using the established WFA-antibody sandwich automated immunoassay. Lectin microarray results showed that WFA specifically recognized N-glycans of agglutinated IgA1 in IgAN patients. The constructed IgA1 standard exhibited a wide dynamic range and high reactivity. In the validation study, serum WFA-reactive IgA1 (WFA+-IgA1) differed significantly between healthy control subjects and IgAN patients. The findings indicate that WFA is a suitable lectin that specifically targets abnormal agglutinated IgA1 in serum. We also describe an automated immunoassay system for detecting WFA+-IgA1, focusing on N-glycans.

Role of Palatine Tonsil and Epipharyngeal Lymphoid Tissue in the Development of Glomerular Active Lesions (Glomerular vasculitis) in Immunoglobulin A Nephropathy.

Hematuria is an essential symptom of immunoglobulin A nephropathy (IgAN). Although the etiology of hematuria in IgAN has not been fully elucidated, it is thought that the rupture of the glomerular basement membranes caused by intra-capillary leukocyte influx, so-called glomerular vasculitis, is the pathological condition responsible for severe hematuria. Glomerular vasculitis are active lesions that exist in the glomeruli of acute phase IgAN and it is important because it is suspected to make the transition to segmental glomerular sclerosis (SGS) as a repair scar lesion in the chronic phase, and the progression of SGS would eventually lead to glomerular obsolescence. Worsening of hematuria concomitant with acute pharyngitis is common in patients with IgAN; therefore, elucidating the relationship between the immune system of Waldeyer's ring, including the palatine tonsil and epipharyngeal lymphoid tissue, and the glomerular vasculitis may lead to understanding the nature of IgAN. The epipharynx is an immunologically activated site even under normal conditions, and enhanced activation of innate immunity is likely to occur in response to airborne infection. Hyperactivation of innate immunity via upregulation of Toll-like receptors in the interfollicular area of the palatine tonsil and epipharyngeal lymphoid tissue, followed by enhanced fractalkine/CX3CR1 interactions, appears to play an important role in the development of glomerular vasculitis in IgAN. As latent but significant epipharyngitis is present in most patients with IgAN, it is plausible that acute upper respiratory infection may contribute as a trigger for the innate epipharyngeal immune system, which is already upregulated in a chronically inflamed environment. Given that epipharyngitis and its effects on IgAN are not fully understood, we propose that the so-called "epipharynx-kidney axis" may provide an important focus for future research.

Pre-treatment hematuria and crescents predict estimated glomerular filtration rate trajectory after methylprednisolone pulse therapy with tonsillectomy for IgA nephropathy.

BACKGROUND: Glomerular hematuria and proteinuria are typical manifestations of IgA nephropathy (IgAN). However, hematuria severity is not considered a useful marker of the potential benefits of corticosteroid administration as proteinuria severity only is included in the current guidelines. METHODS: In this retrospective cohort study, we enrolled 133 patients diagnosed with IgAN through biopsy. We calculated the 2-year estimated glomerular filtration rate (eGFR) slope (mL/min/1.73m2/year) and eGFR trajectory after methylprednisolone pulse therapy using mixed effects models stratified by the Oxford classification and three categories of pre-treatment hematuria: mild [urinary red blood cells (URBCs) < 10/high-power field (HPF)], moderate (URBCs 10-30/HPF), and severe (URBCs ≥ 30/HPF). RESULTS: The severe pre-treatment hematuria group showed a significantly higher likelihood of having crescents (odds ratio (OR), 4.3; 95% confidence interval (CI), 1.7-10.9). In the longitudinal analysis of 103 patients, most of whom underwent tonsillectomy, the severe pre-treatment hematuria group had a significantly higher 2-year eGFR slope after methylprednisolone pulse therapy than the mild and moderate hematuria groups (mild, -0.52 ± 1.97; moderate, -0.32 ± 1.99; severe, 1.44 ± 3.20 mL/min/1.73m2/year). Patients with C2 scores showed a significantly higher 2-year eGFR slope after methylprednisolone pulse therapy than those with C0 and C1 scores (C0, -0.38 ± 1.74; C1, 0.81 ± 3.02; C2, 3.29 ± 3.68 mL/min/1.73m2/year). Analyses of eGFR trajectory after methylprednisolone pulse therapy revealed that the eGFR improved only in patients with severe pre-treatment hematuria or C2 score (Pinteraction with time < 0.001). CONCLUSIONS: The eGFR is likely to improve after methylprednisolone pulse therapy with tonsillectomy in IgAN patients with severe pre-treatment hematuria or a high percentage of crescents.

The Association between Earlobe Creases and Cardiovascular Events in Japanese Hemodialysis Patients: A Prospective Cohort Study.

Objective The earlobe crease, a wrinkle extending from the tragus to the outer border of the earlobe, is a well-known surrogate marker for a high risk of cardiovascular disease. However, information is lacking about its association with cardiovascular events among hemodialysis patients, who already have an increased risk of cardiovascular disease. We tested the hypothesis that earlobe creases are independently associated with the risk of cardiovascular events among Japanese hemodialysis patients. Methods This prospective cohort study followed 247 adult hemodialysis patients with no history of cardiovascular disease for 4 years. The presence of earlobe creases was defined by two researchers using photos of patients' earlobes on both sides while blinded to one another's assessments and clinical data. The primary outcome was defined as the first fatal or nonfatal cardiovascular event (myocardial infarction, ischemic or hemorrhagic stroke, or peripheral vascular disease requiring aortic or peripheral vascular bypass surgery or below- or above-the-knee amputation). A Fine-Gray competing risks regression model was used to examine the association between earlobe creases and cardiovascular events. Results During the 4-year follow-up period, 43 patients suffered cardiovascular events. After the competing risk of non-cardiovascular death was accounted for, patients with earlobe creases had an increased cumulative incidence of cardiovascular events compared to those without earlobe creases (subhazard ratio =2.04, 95% confidence interval: 1.09 to 3.82). This association was no longer significant after adjusting for age. Conclusion Earlobe creases were not independently associated with cardiovascular events among Japanese hemodialysis patients, suggesting that these marks are simply indicative of advanced age.

Proton pump inhibitor use increases the risk of peritonitis in peritoneal dialysis patients.

Peritonitis is a major and the most significant complication of peritoneal dialysis (PD). Although some predictors of peritonitis in PD patients are known, the association between proton pump inhibitor (PPI) use and peritonitis has not been characterized. Here, we examined whether PPI use is a risk factor for the development of peritonitis, based on a single-center retrospective analysis of 230 consecutive Japanese PD patients at Narita Memorial Hospital. We assessed the association between PPI use and subsequent first episode of peritonitis using multivariate Cox proportional hazards models, following adjustment for clinically relevant factors. The median follow-up period was 36 months (interquartile range, 19-57 months). In total, 86 patients (37.4%) developed peritonitis. Analysis with multivariate Cox proportional hazards models revealed the following significant predictors of peritonitis: PPI use (adjusted hazard ratio [HR] = 1.72, 95% confidence interval [CI]: 1.11-2.66; P = 0.016) and low serum albumin level (per g/dl adjusted HR = 0.59, 95% CI: 0.39-0.90; P = 0.014). Thus, PPI use was independently associated with PD-related peritonitis. The results suggest that nephrology physicians should exercise caution when prescribing PPIs for PD patients.

Podocyte penetration of the glomerular basement membrane to contact on the mesangial cell at the lesion of mesangial interposition in lupus nephritis: a three-dimensional analysis by serial block-face scanning electron microscopy.

BACKGROUND: The interaction among the glomerular components plays an important role in the development of glomerular lesions; thus, investigation of the ultrastructural three-dimensional (3D) configuration of the human glomerular cells and extracellular matrix (ECM) is important for understanding the pathogenesis of glomerulosclerosis, especially glomerulonephritis. METHODS: We applied a new technique of serial block-face scanning electron microscopy (SBF-SEM), which helps to acquire serial electron microscopic images to reconstruct a 3D ultrastructure, to a human kidney biopsy specimen obtained from a 25-year-old woman with lupus nephritis. RESULTS: SBF-SEM demonstrated that the cytoplasmic processes of the podocyte penetrated into the lamina densa of the glomerular basement membrane, and was in direct contact with the cytoplasm of mesangial cells at the site of mesangial interposition. CONCLUSION: Although this is a single-case observational study, SBF-SEM revealed a unique 3D configuration, suggesting a novel mechanism of direct intercellular cross-communication between podocytes and mesangial cells, aside from the presumed paracrine communication.

Prevalence of Earlobe Creases and Their Association With History of Cardiovascular Disease in Patients Undergoing Hemodialysis: A Cross-Sectional Study.

Earlobe creases are surrogate markers for high risk of cardiovascular disease. There is no data concerning earlobe creases among hemodialysis patients, who have an increased risk of cardiovascular disease. A cross-sectional study was conducted to determine the prevalence of earlobe creases and their association with prevalent cardiovascular disease among hemodialysis patients. Patients undergoing hemodialysis were recruited from five outpatient hemodialysis centers. Both earlobes were photographed during a dialysis session with the patient in a supine position and the photos evaluated independently by two experienced nephrologists blinded to the participants' clinical characteristics. Prevalent cardiovascular diseases were defined as a history of myocardial infarction, cerebrovascular accident, or peripheral vascular disease. Sensitivity, specificity, and positive and negative predictive values for detection of prevalent cardiovascular disease were calculated. Logistic analysis was used to examine the association between earlobe creases and prevalent cardiovascular disease. Earlobe creases were identified in 24.5% of 330 hemodialysis patients (200 men; mean age, 67.8 years). The prevalence of earlobe creases increased with age for men (P for trend <0.0001), but not for women (P for trend = 0.07). Sensitivity, specificity, and positive and negative predictive values were 30.9% (95% confidence interval, 21.9-41.6), 77.5% (71.9-82.3), 30.9% (21.9-41.6), and 77.5% (71.9-82.3), respectively. Multivariate logistic analyses indicated the prevalence of earlobe crease was not associated with prevalent cardiovascular diseases. The prevalence is similar to that previously reported for Japanese individuals not undergoing dialysis. No association between earlobe creases and prevalent cardiovascular diseases was identified.

Toll-Like Receptor 9 Stimulation Induces Aberrant Expression of a Proliferation-Inducing Ligand by Tonsillar Germinal Center B Cells in IgA Nephropathy.

The TNF family member a proliferation-inducing ligand (APRIL; also known as TNFSF13), produced by myeloid cells, participates in the generation and survival of antibody-producing plasma cells. We studied the potential role of APRIL in the pathogenesis of IgA nephropathy (IgAN). We found that a significant proportion of germinal centers (GCs) in tonsils of patients with IgAN contained cells aberrantly producing APRIL, contributing to an overall upregulation of tonsillar APRIL expression compared with that in tonsils of control patients with tonsillitis. In IgAN GC, antigen-experienced IgD-CD38+/-CD19+ B cells expressing a switched IgG/IgA B cell receptor produced APRIL. Notably, these GC B cells expressed mRNA encoding the common cleavable APRIL-α but also, the less frequent APRIL-δ/ζ mRNA, which encodes a protein that lacks a furin cleavage site and is, thus, the uncleavable membrane-bound form. Significant correlation between TLR9 and APRIL expression levels existed in tonsils from patients with IgAN. In vitro, repeated TLR9 stimulation induced APRIL expression in tonsillar B cells from control patients with tonsillitis. Clinically, aberrant APRIL expression in tonsillar GC correlated with greater proteinuria, and patients with IgAN and aberrant APRIL overexpression in tonsillar GC responded well to tonsillectomy, with parallel decreases in serum levels of galactose-deficient IgA1. Taken together, our data indicate that antibody disorders in IgAN associate with TLR9-induced aberrant expression of APRIL in tonsillar GC B cells.

Association between warfarin use and incidence of ischemic stroke in Japanese hemodialysis patients with chronic sustained atrial fibrillation: a prospective cohort study.

BACKGROUND: Although generally recommended for atrial fibrillation (AF) in the general population, the efficacy and safety of warfarin in hemodialysis patients remains controversial. Warfarin use in hemodialysis patients may confer an additional risk of bleeding that is not appreciated in patients without renal failure because hemodialysis patients have platelet defects and receive anticoagulation agents during dialysis. The incidence of major bleeding was reported to be higher in Japanese AF patients on warfarin therapy compared to patients in other countries, suggesting that racial differences may influence bleeding tendency. Thus, examining risks and benefits of warfarin therapy in Japanese hemodialysis patients with AF is important. METHODS: In order to determine associations between warfarin use and new ischemic stroke events, major bleeding, and all-cause mortality, a prospective cohort study of 60 Japanese hemodialysis patients with chronic sustained AF was conducted using Cox proportional modeling and propensity score matching. RESULTS: The mean patient age was 68.1 years. During 110 person-years of follow-up, 13 ischemic strokes occurred. After adjusting for CHADS2 score, warfarin use was not associated with a significant reduction in ischemic stroke events [hazard ratio (HR) 3.36; 95 % confidence interval (CI) 0.94-11.23]. Similar results were obtained after propensity score matching (HR 3.36; 95 % CI 0.67-16.66). Warfarin use was not associated with significant increases in major bleeding or all-cause mortality. CONCLUSIONS: These results suggest that warfarin may not prevent ischemic stroke in Japanese hemodialysis patients with chronic sustained AF. Adequately powered studies are needed to determine the risks and benefits of anticoagulation therapy in these patients.

A case of "pure" preeclampsia with nephrotic syndrome before 15 weeks of gestation in a patient whose renal biopsy showed glomerular capillary endotheliosis.

A 35-year-old Japanese woman for whom a previous health checkup showed normal blood pressure and urinalysis results without serological abnormalities developed nephrotic syndrome with severe hypertension at 15 gestational weeks. The renal biopsy performed at 17 weeks of gestation showed severe glomerular capillary endotheliosis. By means of electron microscopy, no electron-dense deposits were observed in glomeruli, and foot-process arrangement was normal. Histological findings indicated the patient's glomerular damage was caused by the mechanisms of preeclampsia. The patient underwent an elective abortion at 18 weeks of gestation. Clinical abnormalities vanished completely within 3 months after the elective abortion, which provided additional evidence that proteinuria and hypertension were caused purely by pregnancy. In general, the term preeclampsia refers to new onset of hypertension and proteinuria after 20 weeks of gestation. When proteinuria or hypertension is newly observed before 20 weeks of gestation, they are practically associated with triploidy, trophoblastic disease, or antiphospholipid syndrome. However, our case was not associated with them. Therefore, we called this case "pure" preeclampsia. We confirm the notion for the first time that preeclampsia associated with glomerular capillary endotheliosis can occur before 20 weeks of gestation. In addition, this report describes the earliest onset of preeclampsia compared with previously published reports. We also discuss causes of preeclampsia in early gestation and refer to the issue of the application of renal biopsies during pregnancy.

Acellular pertussis vaccines in Japan: past, present and future.

An antivaccine movement developed in Japan as a consequence of increasing numbers of adverse reactions to whole-cell pertussis vaccines in the mid-1970s. After two infants died within 24 h of the vaccination from 1974 to 1975, the Japanese government temporarily suspended vaccinations. Subsequently, the public and the government witnessed the re-emergence of whooping cough, with 41 deaths in 1979. This series of unfortunate events revealed to the public that the vaccine had, in fact, been beneficial. Furthermore, researchers and the Japanese government proceeded to develop safer pertussis vaccines. Japan now has the most experience worldwide with acellular pertussis vaccines, being the first country to have approved their use. This review describes the major events associated with the Japanese vaccination program. The Japanese experience should be valuable to other countries that are considering the development and use of such vaccines.

Pertussis immunization in the global pertussis initiative international region: recommended strategies and implementation considerations.

Despite widespread immunization programs in most countries, pertussis disease continues to be a threat to public health. In particular, there has been a resurgence of pertussis disease in older children, adolescents and adults, creating a reservoir of infection, which poses a significant threat to infants who are either unimmunized or incompletely immunized. Global Pertussis Initiative participants from Argentina, Australia, Brazil and Japan considered the relative merits of several strategies to reduce the burden of pertussis disease and suggested strategies that might be implemented in these countries. Infants in these countries receive an initial course of 3 doses of vaccine in the first year of life followed by a fourth dose in the second year. Only children in Japan are not given a preschool booster (age 3-5 years). Of the strategies considered, the addition of a preschool booster is therefore a priority in Japan to overcome the problem of waning vaccine-induced immunity to pertussis in school children. Waning immunity also affects adolescents; Australia introduced an adolescent booster in 2003, and the addition of a booster in this age group was suggested for Argentina and Japan. Immunization of new mothers and other close contacts of young infants, such as child care and health care workers, might be appropriate in Australia in the future. Argentina also suggested a future possibility of immunizing health care and child care workers. Obstacles to new immunization strategies include poor access to standardized laboratory diagnostic techniques, inadequate resources to fund new immunization programs, low awareness of pertussis disease in adults and adolescents and inadequate surveillance techniques to assess the full extent of the problems caused by pertussis or the impact new vaccination strategies might have.

Whooping cough due to Bordetella parapertussis: an unresolved problem.

Bordetella parapertussis is one of the bacteria that causes whooping cough. However, little attention has been paid to this bacterium because it causes a milder illness than Bordetella pertussis and the rate of detection is low, even though research suggests that pertussis vaccines have limited efficacy against B. parapertussis infection. However, recent studies have revealed high rates of detection in patients with whooping cough in some field studies. In this review, the relevant studies of B. parapertussis are summarized and it is demonstrated that it is now necessary to pay greater attention to infections by this bacterium.

Podocalyxin activates RhoA and induces actin reorganization through NHERF1 and Ezrin in MDCK cells.

Podocalyxin (PC) is the major sialoglycoprotein expressed on the apical membrane of the podocyte. Previously it was shown that PC is connected to actin through the PC/NHERF2/ezrin complex, and this connection is disrupted in the nephrotic syndrome. For assessing whether expression of PC affects the organization of the actin cytoskeleton, MDCK cell lines stably expressing either full-length PC or a PC mutant lacking the NHERF binding site was established. It was found that full-length PC but not the PC mutant is connected to actin, induces redistribution of actin toward the apical membrane, and leads to increased RhoA activity. By immunofluorescence redistribution of RhoA and RhoGDI was observed in the presence of both full-length PC and the PC mutant. With the use of pulldown assays, PC and ezrin were found to interact directly and the ezrin binding site was mapped to the juxtamembrane region of PC's cytoplasmic tail. It is concluded that PC binds to ezrin both directly and indirectly. PC activates RhoA through NHERF and ezrin, leading to redistribution of actin filaments. These results suggest that in podocytes, PC may also regulate foot process architecture through RhoA.

BopB is a type III secreted protein in Bordetella bronchiseptica and is required for cytotoxicity against cultured mammalian cells.

The cytotoxicity of Bordetella bronchiseptica to infected cells is known to be dependent on a B. bronchiseptica type III secretion system. Although the precise mechanism of the type III secretion system is unknown, BopN, BopD and Bsp22 have been identified as type III secreted proteins. In order to identify other proteins secreted via the type III secretion machinery in Bordetella, a type III mutant was generated, and its secretion profile was compared with that of the wild-type strain. The results showed that the wild-type strain, but not the type III mutant, secreted a 40-kDa protein into the culture supernatant. This protein was identified as BopB by the analysis of its N-terminal amino acid sequence. Severe cytotoxicity such as necrosis was induced in L2 cells by infection with the wild-type B. bronchiseptica. In contrast, this effect was not observed by the BopB mutant infection. The haemolytic activity of the BopB mutant was greatly impaired compared with that of the wild-type strain. The results of a digitonin assay strongly suggested that BopB was translocated into HeLa cells infected with the wild-type strain. Taken together, our results demonstrate that Bordetella secretes BopB via a type III secretion system during infection. BopB may play a role in the formation of pores in the host plasma membrane which serve as a conduit for the translocation of effector proteins into host cells.

The adaptor protein ARH escorts megalin to and through endosomes.

Megalin is an endocytic receptor that binds multiple ligands and is essential for many physiological processes such as brain development and uptake of proteins by the kidney tubule, yolk sac, and thyroid. The cytoplasmic tail of megalin contains two FXNPXY motifs. Autosomal recessive hypercholesterolemia (ARH) is an adaptor protein that binds to the FXNPXY motif of the low-density lipoprotein receptor as well as clathrin and AP-2. We found that ARH also binds to the first FXNPXY motif of megalin in two-hybrid, pull-down and coimmunoprecipitation assays. ARH colocalizes with megalin in clathrin coated pits and in recycling endosomes in the Golgi region. When cells are treated with nocodazole, the recycling endosomes containing megalin and ARH disperse. On internalization of megalin, ARH and megalin are first seen in clathrin coated pits followed by sequential localization in early endosomes and tubular recycling endosomes in the pericentriolar region followed by their reappearance at the cell surface. Expression of ARH in Madin-Darby canine kidney cells expressing megalin mini-receptors enhances megalin-mediated uptake of 125I-lactoferrin, a megalin ligand. These results show that ARH facilitates endocytosis of megalin, escorts megalin along its endocytic route and raise the possibility that transport through the endosomal system is selective and requires interaction with specific adaptor proteins.

Role of systemic and mucosal immune responses in reciprocal protection against Bordetella pertussis and Bordetella parapertussis in a murine model of respiratory infection.

The roles of systemic humoral immunity, cell-mediated immunity, and mucosal immunity in reciprocal protective immunity against Bordetella pertussis and Bordetella parapertussis were examined by using a murine model of respiratory infection. Passive immunization with serum from mice infected with B. pertussis established protective immunity against B. pertussis but not against B. parapertussis. Protection against B. parapertussis was induced in mice that had been injected with serum from mice infected with B. parapertussis but not from mice infected with B. pertussis. Adoptive transfer of spleen cells from mice infected with B. pertussis or B. parapertussis also failed to confer reciprocal protection. To examine the role of mucosal immunity in reciprocal protection, mice were infected with preparations of either B. pertussis or B. parapertussis, each of which had been incubated with the bronchoalveolar wash of mice that were convalescing after infection with B. pertussis or B. parapertussis. Such incubation conferred reciprocal protection against B. pertussis and B. parapertussis on infected mice. The data suggest that mucosal immunity including secreted immunoglobulin A in the lungs might play an important role in reciprocal protective immunity in this murine model of respiratory infection.