Impact of tonsillectomy combined with steroid pulse therapy on immunoglobulin A nephropathy depending on histological classification: a multicenter study.

BACKGROUND: In addition to corticosteroids and inhibition of the renin-angiotensin-aldosterone system, tonsillectomy with steroid pulse therapy (TSP) may have a beneficial impact on the clinical course of IgA nephropathy (IgAN). However, there is still much uncertainty regarding the indications for therapy, treatment protocol, and therapeutic options for IgAN. METHODS: In this multicenter retrospective cohort study, we enrolled 284 patients with biopsy-proven IgAN who received TSP or corticosteroid therapy or conservative therapy. The effects of TSP on clinical remission (CR) were evaluated after a median follow-up period of 4.1 years in relation to histological classifications. RESULTS: Among the 284 participants, 161 patients received TSP. During the observation time, 141 patients (49.6%) achieved CR, with a median time to remission of 397 days. In multivariate Cox regression analyses, TSP had an impact on achieving CR in only the group with histological grade 3 defined as glomerulosclerosis, crescent formation or adhesion to Bowman's capsule in 10-30% of all biopsied glomeruli, or mild cellular infiltration in the interstitium (hazard ratio (HR) 4.29, 95% confidence interval (95%CI) 1.88-11.19, P < 0.001). TSP independently contributed to a higher incidence of CR, particularly in the patient group showing evident mesangial hypercellularity (HR 2.54, 95%CI 1.38-5.08, P = 0.002). CONCLUSIONS: TSP may have a beneficial effect on the clinical course in IgAN patients with mild to moderate glomerular and interstitial lesions, particularly with distinct mesangial cell proliferation.

Neuromedin U has a novel anorexigenic effect independent of the leptin signaling pathway.

Neuromedin U (NMU) is a hypothalamic neuropeptide that regulates body weight and composition. Here we show that mice lacking the gene encoding NMU (Nmu(-/-) mice) develop obesity. Nmu(-/-) mice showed increased body weight and adiposity, hyperphagia, and decreased locomotor activity and energy expenditure. Obese Nmu(-/-) mice developed hyperleptinemia, hyperinsulinemia, late-onset hyperglycemia and hyperlipidemia. Notably, however, treatment with exogenous leptin was effective in reducing body weight in obese Nmu(-/-) mice. In addition, central leptin administration did not affect NMU gene expression in the hypothalamus of rats. These results indicate that NMU plays an important role in the regulation of feeding behavior and energy metabolism independent of the leptin signaling pathway. These characteristic functions of NMU may provide new insight for understanding the pathophysiological basis of obesity.

An integrin-activating peptide, PHSRN, ameliorates inhibitory effects of conventional peritoneal dialysis fluids on peritoneal wound healing.

BACKGROUND: Bioincompatible peritoneal dialysis fluids (PDFs) cause pathological changes in the peritoneal membrane, related to membrane dysfunction and progressive peritoneal fibrosis. We investigated the effects of Pro-His-Ser-Arg-Asn (PHSRN) peptide, one of the fibronectin cell-binding domains that activates integrins and reinforces wound healing, on peritoneal remodelling in a rat peritoneal injury model undergoing peritoneal dialysis. METHODS: The peritoneal mesothelial monolayer was removed by a stripping procedure in rats receiving conventional high glucose-containing PDF supplemented with or without PHSRN or control His-Ser-Pro-Asn-Hrg (HSPNR) peptides. Effects of PHSRN on cell motility and signalling molecules were examined in cultured rat peritoneal mesothelial cells (RPMCs) and normal rat kidney fibroblasts (NRKs). RESULTS: The cytokeratin- and HBME-1-positive mesothelial cell monolayer was selectively removed by the procedure. By day 6, HBME-1-positive cells had regenerated to 53.3 +/- 6.5% of the peritoneal surface in the control group. Regeneration of the mesothelial layer was delayed in the PDF group (35.2 +/- 10.2%, P < 0.05), but PHSRN reversed the effects of PDF (51.7 +/- 9.6%, P < 0.05). PDF treatment increased thickening of granulomatous submesothelial tissue and numbers of ED1-, CD31- and alpha-smooth muscle actin-positive cells, but PHSRN ameliorated these effects. HSPNR had no effects on mesothelial regeneration or peritoneal wound healing. PHSRN, but not HSPNR, recovered glucose-induced inhibition of cell motility and phosphorylation of focal adhesion kinase and its downstream p130(Cas) in RPMCs and NRKs. CONCLUSIONS: These results suggest that PHSRN has beneficial effects on peritoneal regeneration by reducing the inhibitory effects of conventional PDF on integrin-mediated wound healing.

Minimal change nephrotic syndrome in a patient with strongyloidiasis.

Strongyloidiasis, a chronic infection caused by the intestinal parasite Strongyloides stercoralis, is prevalent in the Nansei Islands of Japan. Here, we report our findings on a case of strongyloidiasis complicated with steroid-resistant minimal change nephrotic syndrome in a 69-year-old male resident of Fukuoka Prefecture who had lived in Yakushima, one of the Nansei Islands, until age 15. In October 2006, he developed proteinuria and edema, and was diagnosed with minimal change nephrotic syndrome on the basis of the renal biopsy findings. Following treatment with prednisolone, the level of proteinuria decreased to 0.29 g/day by day 35. However, 5 days later (day 40), the patient developed persistent watery diarrhea and vomiting, leading to dehydration and malnutrition. Pneumonia and bacterial meningitis subsequently developed (day 146); filarial (infectious-type) and rhabditiform (noninfectious-type) S. stercoralis larvae were detected for the first time in the patient's sputum, gastric juice, feces, and urine. Although treatment with ivermectin was started immediately and the parasitosis responded to the treatment, the patient died of sepsis. Consequently, although strongyloidiasis is a rare infection except in endemic regions, it is essential to consider the possibility of this disease and begin treatment early for patients who have lived in endemic areas and who complain of unexplained diarrhea during steroid-induced or other immunosuppression.

Changes in gene expressions of hypothalamic neuropeptides controlling feeding behaviors in bilateral nephrectomized rats.

Anorexia is one of the most widespread eating disorders that appears to contribute to malnutrition in patients with advanced kidney dysfunction. The changes of neuropeptides controlling feeding behaviors synthesized in the hypothalamus under several physiological condition could induce anorexia. While several mechanisms underlying uremic anorexia have been proposed, the changes of hypothalamic neuropeptides controlling feeding behaviors of uremic patients are poorly understood. The gene expressions of hypothalamic neuropeptides controlling feeding behaviors were evaluated after bilateral nephrectomy, which is a model of acute kidney dysfunction, by in situ hybridization histochemistry. Food consumption decreased markedly in bilateral nephrectomized rats. The mRNA levels of corticotrophin-releasing hormone, proopiomelanocortin, cocaine- and amphetamine-regulated transcript, which suppress feeding behavior, were significantly higher in bilateral nephrectomized rats than in sham-operated rats. On the other hand, the mRNA levels of Agouti-related peptide, neuropeptide Y, melanin-concentrating hormone, and orexin, which promote feeding behavior, were significantly lower in bilateral nephrectomized rats than in sham-operated rats. In addition, the plasma level of leptin, which has an anorexic effect, increased after bilateral nephrectomy. The results suggest that hypothalamic neuropeptides controlling feeding behaviors may be involved in the development of anorexia in bilateral nephrectomized rats. This report is the first step to elucidating the physiological mechanisms of anorexia in patients with kidney dysfunction.

Effects of acute kidney dysfunction on hypothalamic arginine vasopressin synthesis in transgenic rats.

Acute loss of kidney function is a critical internal stressor. Arginine vasopressin (AVP) present in the parvocellular division of the paraventricular nucleus (PVN) plays a key role in the regulation of stress responses. However, hypothalamic AVP dynamics during acute kidney dysfunction remain unclear. In this study, we investigated the effects of bilateral nephrectomy on AVP, using a transgenic rat line that expressed the AVP-enhanced green fluorescent protein (eGFP). The eGFP fluorescent intensities in the PVN were dramatically increased after bilateral nephrectomy. The mRNA levels of eGFP, AVP, and corticotrophin-releasing hormone in the PVN were dramatically increased after bilateral nephrectomy. Bilateral nephrectomy also increased the levels of Fos-like immunoreactive cells in brainstem neurons. These results indicate that bilateral nephrectomy upregulates the AVP-eGFP synthesis. Further studies are needed to identify the neural and/or humoral factors that activate AVP synthesis and regulate neuronal circuits during acute kidney dysfunction.

Upregulation of hypothalamic arginine vasopressin by peripherally administered furosemide in transgenic rats expressing arginine vasopressin-enhanced green fluorescent protein.

Furosemide, which is used worldwide as a diuretic agent, inhibits sodium reabsorption in the Henle's loop, resulting in diuresis and natriuresis. Arginine vasopressin (AVP) is synthesized in the supraoptic nucleus (SON), paraventricular nucleus (PVN), and suprachiasmatic nucleus (SCN) of the hypothalamus. The synthesis AVP in the magnocellular neurons of SON and PVN physiologically regulated by plasma osmolality and blood volume and contributed water homeostasis by increasing water reabsorption in the collecting duct. Central AVP dynamics after peripheral administration of furosemide remain unclear. Here, we studied the effects of intraperitoneal (i.p.) administration of furosemide (20 mg/kg) on hypothalamic AVP by using transgenic rats expressing AVP-enhanced green fluorescent protein (eGFP) under the AVP promoter. The i.p. administration of furosemide did not affect plasma osmolality in the present study; however, eGFP in the SON and magnocellular divisions of the PVN (mPVN) were significantly increased after furosemide administration compared to the control. Immunohistochemical analysis revealed Fos-like immunoreactivity (IR) in eGFP-positive neurons in the SON and mPVN 90 min after i.p. administration of furosemide, and AVP heteronuclear (hn) RNA and eGFP mRNA levels were significantly increased. These furosemide-induced changes were not observed in the suprachiasmatic AVP neurons. Furthermore, furosemide induced a remarkable increase in Fos-IR in the organum vasculosum laminae terminals (OVLT), median preoptic nucleus (MnPO), subfornical organ (SFO), locus coeruleus (LC), nucleus of the solitary tract (NTS), and rostral ventrolateral medulla (RVLM) after i.p. administration of furosemide. In conclusion, we were able to visualize and quantitatively evaluate AVP-eGFP synthesis and neuronal activations after peripheral administration of furosemide, using the AVP-eGFP transgenic rats. The results of this study may provide new insights into the elucidation of physiological mechanisms underlying body fluid homeostasis induced by furosemide. This article is protected by copyright. All rights reserved.

Monocarboxylate Transporter-1 Mediates the Protective Effects of Neutral-pH Bicarbonate/Lactate-Buffered Peritoneal Dialysis Fluid on Cell Viability and Apoptosis.

We investigated the effects of bicarbonate/lactate-buffered peritoneal dialysis fluid (B/L-PDF) and lactate-buffered PDF (L-PDF) on cell viability and apoptosis, focusing on monocarboxylate transporters (MCTs). MCT-1 transports lactate into cells. Cell viability and apoptosis of human peritoneal mesothelial cells (HPMCs) were examined by water-soluble tetrazolium salt-1 and TUNEL assays, respectively. The relative number of viable HPMCs was significantly decreased by L-PDF at 48 h (8.8 ± 0.4%) compared with cells cultured in M199, but not by B/L-PDF (66.7 ± 1.1%). Apoptosis was markedly induced by L-PDF at 48 h (69.3 ± 16.2%), but not by B/L-PDF (2.6 ± 0.3%). Knockdown of MCT-1 by small interfering RNA (siRNA) attenuated the L-PDF-induced reduction of viable cells and increased apoptosis compared with control siRNA, but MCT-4 knockdown had no effect. B/L-PDF had lesser effects on cell viability and apoptosis of HPMCs compared with L-PDF. These results suggest that B/L-PDF biocompatibility occurs by avoiding the induction of apoptosis in HPMCs.

Corrigendum to "High glucose concentration-induced expression of pentraxin-3 in a rat model of continuous peritoneal dialysis".

This correct the article DOI: 10.14670/HH-11-756.

High glucose concentration-induced expression of pentraxin-3 in a rat model of continuous peritoneal dialysis.

BACKGROUND: Continuous exposure to peritoneal dialysis fluids (PDFs) is associated with pathological responses such as persistent micro-inflammation, which leads to ultrafiltration failure. Pentraxin-3 (PTX3), a multifunctional soluble pattern recognition receptor, is produced at sites of inflammation by a wide range of cell types. This study investigates the in vivo expression of PTX3 in the peritoneal membrane of a rat continuous peritoneal dialysis (PD) model, as well as the effect of high glucose on the in vitro expression of PTX3. METHODS: The expression of PTX3 was analyzed using RT-PCR, real-time PCR, immunohistochemistry and western blotting in a PD rat model receiving saline or conventional PDF containing 3.86% glucose for 8 weeks. The effects of high glucose on the expression of PTX3 were examined in cultured rat peritoneal mesothelial cells (RPMCs), mouse macrophage-like cells, and mouse fibroblasts. RESULTS: In a rat model of PD, eight-week instillation of the conventional PDF produced increased submesothelial thickening, followed by substantially enhanced PTX3 protein levels in the submesothelial layer of peritoneal membrane. PTX3 was detected in peritoneal mesothelial cells, macrophages and fibroblasts in the thickened submesothelial area. Glucose was found to induce PTX3 protein expression in RPMCs as well as macrophage-like cells and fibroblasts. CONCLUSION: Continuous exposure to conventional PDF induces PTX3 expression in the peritoneal membrane of rats. High glucose may be involved in the mechanism of PDF-induced local micro-inflammation in the peritoneum.

Transgenic expression of enhanced green fluorescent protein enables direct visualization for physiological studies of vasopressin neurons and isolated nerve terminals of the rat.

We have generated transgenic rats expressing an arginine vasopressin (AVP)-enhanced green fluorescent protein (eGFP) fusion gene. The expression of the eGFP gene and strong fluorescence were observed in the supraoptic nucleus (SON), the paraventricular nucleus (PVN), and the suprachiasmatic nucleus (SCN) in transgenic rats. The hypothalamo-neurohypophyseal tract, isolated SON neurons, and isolated axon terminals in the neurohypophysis also showed robust eGFP fluorescence. Water deprivation for 2 d increased the fluorescence of the eGFP in the SON and the PVN but not the SCN. The whole-cell patch-clamp technique was then used to record the electrical activities specifically identifying eGFP-expressing SON, PVN, and SCN AVP neurons in in vitro brain slice preparations. The AVP-eGFP transgenic rats are a unique new tool with which to study the physiological role of AVP-secreting neurons in the central nervous system and the dynamics of the regulation of AVP secretion in the living neurons and their axon terminals.

A novel UMOD gene mutation associated with uromodulin-associated kidney disease in a young woman with moderate kidney dysfunction.

Uromodulin-associated kidney disease (UAKD) is an autosomal dominant disease caused by a mutation in the uromodulin (UMOD) gene, leading to end-stage renal disease. We herein report the case of a family with UAKD caused by a novel mutation (C135G) in the UMOD gene. A 31-year-old woman had a low estimated glomerular filtration rate (59.7 mL/min per 1.73 m(2)). Her father, grandfather and paternal aunt had received maintenance hemodialysis therapy since their 40's. This case underscores the importance of performing genetic testing in young patients even in cases involving only moderate abnormalities in the kidney function.

Six-hour selective REM sleep deprivation increases the expression of the galanin gene in the hypothalamus of rats.

The effect of short-term selective REM sleep deprivation (RSD) on the gene expression of galanin in the rat hypothalamus was examined using in situ hybridization histochemistry. Monitoring an electroencephalogram (EEG) and electromyogram (EMG) on an on-line computer screen, as the RSD rats entered REM sleep, they were gently stroked on their backs using a brush to wake them during the RSD period. Galanin mRNA levels in the preoptic area (POA) were significantly increased by RSD for a period of 6 h. RSD had no significant effect on the mRNA levels of corticotrophin-releasing factor (CRF), arginine vasopressin (AVP), oxytocin (OXT) or orexins. These results suggest that 6-h selective RSD may not be sufficient to induce the activation of the hypothalamo-pituitary adrenal axis, and that the expression of the galanin gene in the hypothalamus reacts more readily against the loss of REM sleep in comparison to other hypothalamic neuropeptides such as arginine vasopressin, oxytocin and orexins.

Disassociated increases of adrenomedullin in the rat cerebrospinal fluid and plasma after salt loading and systemic administration of lipopolysaccharide.

To determine the role of adrenomedullin (AM) in the fluid electrolyte homeostasis and endotoxin shock, cerebral spinal fluid (CSF) and plasma were sampled from rats after respective challenges. The AM levels were measured by a highly sensitive immunoassay. The AM levels in the CSF of the rats anesthetized with ether (10.7 +/- 0.60 fmol/ml) were significantly higher than those with isoflurane 5.17 +/- 0.70 fmol/ml, P < 0.01), while the plasma level did not differ significantly. The CSF levels of the rats received 2% saline drinking increased to 3 and 4 folds at day 5 and day 7, respectively, while the plasma levels did not differ from controls at both time points. The AM levels in CSF or plasma increased to 1.5 and 3 folds at 1.5 h after intraperitoneal (i.p.) administration of lipopolysaccharide (LPS, 5 mg/kg), reached 6.5 and 30 folds at 6 h, respectively, while no change was observed in the controls. The present findings suggest that AM in the CSF is regulated independently from that in the plasma, the centrally synthesized AM plays and important role in the regulation of the fluid electrolyte homeostasis. Furthermore, the circulatory AM plays an important role in the endotoxin shock.

Effects of restricted feeding on the activity of hypothalamic Orexin (OX)-A containing neurons and OX2 receptor mRNA level in the paraventricular nucleus of rats.

We have examined the effects of 3 weeks of food restriction on both the activity of neurons containing hypothalamic orexin (OX)-A and the level of OX receptor type 2 (OX2R) mRNA in the paraventricular nucleus (PVN) of rats. Double immunohistochemistry was used to examine the expression of OX-A and Fos in the lateral hypothalamic area (LHA), and in situ hybridization histochemistry was used to measure levels of OX2R mRNA in the PVN. After the period of restricted feeding, 20-30% of OX-A-containing neurons exhibited Fos-like immunoreactivity (LI). The distribution of OX-A-LI/Fos-LI cells in the food-restricted rats was similar to that observed in glucose-deprived rats after intracerebroventricular (icv) administration of 2-deoxy-D-glucose (2-DG). In addition, 3 weeks of food restriction caused a significant decrease in the expression of the OX2R gene in the parvocellular division of the PVN. These results suggest that the activation of OX-A-containing neurons induced by restricted feeding may be involved in neuroendocrine responses to food restriction.

Upregulation of CRH gene expression and downregulation of arginine vasopressin gene expression in the hypothalamus of bilateral nephrectomized rats.

The expression of the corticotropin-releasing hormone (CRH) gene and the arginine vasopressin (AVP) gene in the hypothalamus examined in bilateral nephrectomized rats by in situ hybridization histochemistry. The expression of the CRH gene was significantly increased in the parvocellular part of the paraventricular nucleus (PVN) 12 and 20 h after bilateral nephrectomy in comparison with that after sham operation. The plasma concentration of adrenocorticotropic hormone (ACTH) in nephrectomized rats was significantly higher than that in sham operated rats 20 h after surgery. In contrast, the expression of the AVP gene in both the parvocellular and magnocellular parts of the PVN and throughout the supraoptic nucleus (SON) was significantly decreased 20 h after bilateral nephrectomy in comparison with that after sham operation. These results suggest that nephrectomy-induced upregulation of the CRH gene with elevation of plasma ACTH may be due to the activation of the hypothalamo-pituitary adrenal (HPA) axis.

Impacts of icodextrin on integrin-mediated wound healing of peritoneal mesothelial cells.

AIMS: Exposure to glucose and its metabolites in peritoneal dialysis fluid (PDF) results in structural alterations of the peritoneal membrane. Icodextrin-containing PDF eliminates glucose and reduces deterioration of peritoneal membrane function, but direct effects of icodextrin molecules on peritoneal mesothelial cells have yet to be elucidated. We compared the impacts of icodextrin itself with those of glucose under PDF-free conditions on wound healing processes of injured mesothelial cell monolayers, focusing on integrin-mediated cell adhesion mechanisms. MAIN METHODS: Regeneration processes of the peritoneal mesothelial cell monolayer were investigated employing an in vitro wound healing assay of cultured rat peritoneal mesothelial cells treated with icodextrin powder- or glucose-dissolved culture medium without PDF, as well as icodextrin- or glucose-containing PDF. The effects of icodextrin on integrin-mediated cell adhesions were examined by immunocytochemistry and Western blotting against focal adhesion kinase (FAK). KEY FINDINGS: Cell migration over fibronectin was inhibited in conventional glucose-containing PDF, while icodextrin-containing PDF exerted no significant inhibitory effects. Culture medium containing 1.5% glucose without PDF also inhibited wound healing of mesothelial cells, while 7.5% icodextrin-dissolved culture medium without PDF had no inhibitory effects. Glucose suppressed cell motility by inhibiting tyrosine phosphorylation of FAK, formation of focal adhesions, and cell spreading, while icodextrin had no effects on any of these mesothelial cell functions. SIGNIFICANCE: Our results demonstrate icodextrin to have no adverse effects on wound healing processes of peritoneal mesothelial cells. Preservation of integrin-mediated cell adhesion might be one of the molecular mechanisms accounting for the superior biocompatibility of icodextrin-containing PDF.

Fluvastatin attenuates IGF-1-induced ERK1/2 activation and cell proliferation by mevalonic acid depletion in human mesangial cells.

AIMS: Insulin-like growth factor (IGF)-1 is a major mitogenic growth factor for mesangial cells (MCs). Statins slow the progression of chronic kidney disease by affecting inflammatory cell signaling pathways, in addition to improving lipid profile, however, no studies have investigated the effects of fluvastatin on mitogen-activated protein (MAP) kinase activity or MC proliferation in kidney cells. We investigated the effects of fluvastatin on IGF-1-induced activation of intracellular signal pathways and MC proliferation, and examined the inhibitory mechanisms of fluvastatin. MAIN METHODS: Western blotting and cell proliferation assay were used. KEY FINDINGS: IGF-1 induced phosphorylation of extracellular-related kinase (ERK)1/2, MAP or ERK kinase (MEK)1/2, and Akt, expression of cyclin D1, and MC proliferation in cultured human MCs. Fluvastatin or PD98059, an MEK1 inhibitor, completely abolished IGF-1-induced MEK1/2 and ERK1/2 phosphorylation and MC proliferation, whereas inhibition of Akt had no effect on MC proliferation. Mevalonic acid prevented fluvastatin inhibition of IGF-1-induced MEK1/2 and ERK1/2 phosphorylation, cyclin D1 expression, and MC proliferation. SIGNIFICANCE: Fluvastatin inhibits IGF-1-induced activation of the MAP kinase pathway and MC proliferation by mevalonic acid depletion, and might have renoprotective effects by inhibiting IGF-1-mediated MC proliferation.

A case report of steroid-resistant antineutrophil cytoplasmic antibody-related vasculitis successfully treated by mizoribine in a hemodialysis patient.

Mizoribine (MZR) has shown to be effective against antineutrophil cytoplasmic antibody (ANCA)-related vasculitis; however, no reports have described the successful treatment of steroid-resistant ANCA-related vasculitis with MZR in patients with renal insufficiency requiring hemodialysis. We herein report the case of a 39-year-old man undergoing hemodialysis in whom MZR successfully lowered the myeloperoxidase (MPO)-ANCA titer accompanied by remission of interstitial pneumonia, together with the pharmacokinetics of MZR. The patient developed severe renal insufficiency and interstitial pneumonia, and was started on hemodialysis. Although prednisolone was administered followed by azathioprine, the MPO-ANCA level and interstitial pneumonia showed insufficient improvement. Azathioprine was replaced by MZR and the administered dose of MZR was determined by measuring serum concentrations of MZR at the start of the dialysis session; this was because we confirmed that MZR could only be removed via dialysis, and that the serum concentration of MZR was maintained until the next dialysis session. The maintenance dose was finally set at MZR 75 mg after each dialysis. Subsequently, the ANCA titer decreased and interstitial pneumonia resolved without any MZR-related side effects. This case demonstrates that MZR is safe and effective, even in patients with steroid-resistant ANCA-related vasculitis undergoing hemodialysis, and can be monitored by measuring serum concentrations of MZR.