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Introduction: Isolated ultrafiltration (IUF) is an alternative treatment for diuretic-resistant patients with fluid retention. Although hemodialysis (HD) predominantly decreases extracellular water (ECW), the impact of IUF on fluid distribution compared with HD remains unclear. Methods: We compared the effect of HD (n = 22) and IUF (n = 10) sessions on the body fluid status using a bioimpedance analysis device (InBody S10). Results: The total ultrafiltration volume was similar between HD and IUF (HD 2.5 ± 0.3 vs. ICF 2.1 ± 0.3 L/session, p = 0.196). The reduction rate of ECW was significantly higher than that of intracellular water (ICW) after HD (ECW −7.9% ± 0.8% vs. ICW −3.0% ± 0.9%, p < 0.001) and IUF (ECW −5.8% ± 0.9% vs. ICW -3.6% ± 0.8%, p = 0.048). However, the change in the ratio of ECW to total body water in HD was significantly larger than that in IUF (HD −3.2% ± 0.3% vs. ICF −1.1% ± 0.4%, p < 0.001). The reduction rates in serum tonicity (effective osmolality) were higher after HD than after IUF (HD −1.8% ± 0.5% vs. IUF −0.6% ± 0.2%, p = 0.052). Among the components of effective osmolality, the reduction rates of serum K+ and glucose levels after HD were significantly higher than those after IUF (serum K+: HD −30.5% ± 1.6% vs. IUF −0.5% ± 3.8%, p < 0.001; serum glucose: HD −15.4% ± 5.0% vs. IUF 0.7% ± 4.8%, p = 0.026), while the serum Na+ level was slightly and similarly reduced (HD −0.8% ± 0.4% vs. IUF −0.8% ± 0.4%, p = 0.500). The reduction in the osmolal gap value (measured osmolality–calculated osmolarity) was significantly greater after HD sessions than after IUF sessions (HD −12.4 ± 1.4 vs. IUF 2.0 ± 1.0 mOsm/kg, p = 0.001). Conclusion: The extracellular fluid reduction effect of HD is stronger than that of IUF. The different changes in effective osmolality and osmolal gap after HD and IUF sessions may be related to the different effects of HD and IUF on fluid distribution.

We retrospectively compared the post-transplantation graft survival and the donor's estimated glomerular filtration rates (eGFRs) following living donor kidney transplantations (LDKTs) involving medically complex living donors (MCLDs) (the elderly and patients with obesity, hypertension, diabetes mellitus, or reduced renal function) and standard living donors (SLDs). The clinical data on patients who underwent LDKTs at our institution from 2006-2019, including 192 SLDs and 99 MCLDs, were evaluated. Regarding recipients, the log-rank test and multivariable Cox proportional hazards analyses showed a higher incidence of overall and death-censored graft loss in the recipients who received kidneys from MCLDs (Hazard ratio = 2.16 and 3.25, P = 0.015 and 0.004, respectively), after adjusting for recipient-related variables including age, sex, duration of dialysis, ABO compatibility, and donor-specific antibody positivity. Regarding donors, a linear mixed model showed significantly lower postdonation eGFRs (-2.25 ml/min/1.73 m2 , P = 0.048) at baseline in MCLDs than SLDs, but comparable change (difference = 0.01 ml/min/1.73 m2 /year, P = 0.97). In conclusion, although kidneys from MCLDs are associated with impaired graft survival, the donation did not adversely affect the MCLDs' renal health in at least the short-term. LDKTs involving carefully selected MCLDs would be an acceptable alternative for recipients with no SLDs.

The new type 2 diabetes drug, dapagliflozin, reduces blood glucose levels and body weight by inhibiting sodium glucose transporter 2 (SGLT2) in proximal tubular cells. SGLT2 inhibitors might modulate glucose influx into renal tubular cells, thereby regulating the metabolic conditions that cause endoplasmic reticulum (ER) stress in the cells. In this study, we examined the effect of dapagliflozin on ER stress in the HK-2 proximal tubular cell line and in the kidney of db/db mice to characterise its function in diabetic nephropathy (DN). We found that dapagliflozin regulated ER stress-mediated apoptosis in vitro and in vivo. Only the elf2α-ATF4-CHOP pathway was regulated under these conditions. Notably, the drug rescued C2 ceramide-induced ER stress-mediated apoptosis and ER stress-mediated apoptosis, which might occur in DN, in db/db mice. Our study shows a novel role for dapagliflozin as an inhibitor of ER stress and suggests that dapagliflozin might be useful for the prevention of DN.

A 73-year-old man with liver cirrhosis and advanced chronic kidney disease was admitted to our hospital due to bilateral lower leg edema and appetite loss. Furosemide to treat fluid retention markedly decreased extracellular water compared with intracellular water, but the addition of tolvaptan equally decreased both with a greater diuretic response than furosemide alone. Furthermore, tolvaptan administration increased the plasma colloid osmotic pressure, which might facilitate the shift of fluid from the extravascular space to the intravascular space. This is the first case showing different effects on the fluid distribution between furosemide and additional tolvaptan in the same patient.

Aim Wilms' tumour 1 (WT1) is essential for normal podocyte function. Previous reports have demonstrated that the WT1 promoter is often methylated in cancers, leading to transcriptional silencing. Transforming growth factor-β1 (TGF-β1) is reported to down-regulate WT1 expression in podocytes. Based on the hypothesis that epigenetic modification plays a role in this process, we examined whether TGF-β1 affects the methylation status of WT1 regulatory regions. Methods Conditional immortalized human podocytes were treated with TGF-β1. A human renal proximal tubular epithelial cell line (HK2), which does not express WT1, was used as a control. The degree of DNA methylation of the WT1 promoter, 5' enhancer, intron 3 enhancer and 3' enhancer was determined using quantitative methylation-specific PCR, bisulfite sequencing and pyrosequencing. Results Both WT1 mRNA and protein expression were reduced by long-term treatment with TGF-β1. The WT1 promoter was hypomethylated, and the 5' enhancer and intron 3 enhancer were substantially methylated in untreated podocytes. In contrast, in HK2 cells, the WT1 promoter was strongly methylated, and the 5' enhancer and intron 3 enhancer were less methylated than in untreated podocytes. TGF-β1 tended to increase WT1 promoter methylation, tended to decrease 5' enhancer methylation and significantly decreased intron 3 enhancer methylation in podocytes. Methylation levels of the 3' enhancer did not differ among untreated cells, TGF-β1-treated podocytes or HK2 cells. Conclusion Our data suggest that the methylation pattern of the WT1 promoter and enhancers in human podocytes are distinctive from those in HK2. Furthermore, TGF-β1 alters the methylation levels of the WT1 promoter and enhancers in human podocytes. This modification may be relevant to the attenuation of WT1 by TGF-β1, which could contribute to podocyte injury.

Pregnancy is an important issue for many women with systemic lupus erythematosus (SLE). This study examined maternal and fetal outcomes among SLE women with or without a history of lupus nephritis (LN). We retrospectively analyzed 98 pregnancies in 57 women previously diagnosed with SLE who gave birth at our hospital. There were 44 pregnancies in women with a history of LN and 54 pregnancies in those without. Fetal loss was observed in 16.1% of SLE pregnancies when excluding induced abortion, and preeclampsia and SLE flare were observed in 12.2 and 6.1% of SLE pregnancies, respectively. No significant differences were evident between women with or without LN in rate of fetal loss, preeclampsia or SLE flare. Women with a history of LN exhibited a significantly shorter duration of gestation (37.0 weeks vs. 38.4 weeks, P = 0.006) and lower birth weight (2484 g vs. 2746 g, P = 0.007) than those without LN. Multivariate analysis revealed glucocorticoid dose but not history of LN, as an independent risk factor for preterm delivery and low birth weight. This study was unable to conclude that a history of LN predicted pregnancy outcomes among SLE women. Instead, a higher dose of glucocorticoid at conception was unexpectedly associated with preterm delivery and low birth weight. Further studies are awaited to verify the relationship.

Nivolumab is an anti-programmed cell death-1 (PD-1) antibody that is utilized as an immune checkpoint inhibitor (ICI) for cancer therapy. We herein present the case of a 57-year-old man who developed acute kidney injury during treatment with nivolumab for lung cancer. A renal biopsy revealed acute tubulointerstitial nephritis. Immunohistochemical staining demonstrated marked infiltration of macrophages and T cells together with mild B cell infiltration. Of note, strong CD163+ M2 macrophage infiltration was observed. The cessation of nivolumab and high-dose prednisolone therapy improved the renal function of the patient. Further, we review the pertinent literature on renal-infiltrating cells in ICI-induced tubulointerstitial nephritis.

Acute kidney injury (AKI) is a common but complex condition that is associated with increased morbidity and mortality. In the present study, we examined whether urinary activin A, a member of the TGF-beta superfamily, is present in mice with ischemia-reperfusion injury and in humans with AKI, as well as its potential as a biomarker for AKI. Expression of activin A was markedly increased in ischemic mouse kidneys. In situ hybridization demonstrated that activin mRNA was expressed in tubular cells of ischemic kidneys but not of normal kidneys. Immunoreactive activin A, which was absent in normal kidneys, was detected in the cytoplasm of proximal tubular cells in ischemic kidneys. Activin A was undetectable in the urine of normal mice. In contrast, activin A was significantly increased in the urine of ischemic mice at 3 h after reperfusion. Urinary activin A levels increased according to the period of ischemia. In humans, urinary activin A was almost undetectable in healthy volunteers and in patients with pre-renal AKI, but was significantly increased in patients with renal AKI. There was no significant correlation between urinary activin A and serum activin A. Collectively, urinary activin A might be a useful biomarker reflecting the severity of AKI.

Activin A, a member of the transforming growth factor-beta superfamily, is a critical modulator of inflammation and plays a key role in controlling the cytokine cascade that drives the inflammatory response. However, the role of activin A in inflammatory kidney diseases remains unknown. To address this issue, we examined here whether activin A can be detected in the kidney and/or urine from patients with antineutrophil cytoplasmic antibody (ANCA) -associated vasculitis (AAV). Fifty-one patients who had been diagnosed with AAV and were treated in our department between November 2011 to March 2018 were included in this study. Forty-one patients had renal complications (renal AAV). Serum and urinary activin A levels were measured by enzyme-linked immunosorbent assay. Correlation of urinary activin A concentration with clinical parameters was analyzed. Urinary activin A was undetectable in healthy volunteers. In contrast, urinary activin A concentration was significantly increased in patients with renal AAV but not in those with non-renal AAV. Urinary activin A concentration decreased rapidly after immunosuppressive treatment. There was a significant correlation of urinary activin A level with urinary protein, L-FABP, and NAG. Histologic evaluation revealed that urinary activin A levels were significantly higher in patients with cellular crescentic glomeruli than in those lacking this damage. In situ hybridization demonstrated that the mRNA encoding the activin A βA subunit was undetectable in normal kidneys but accumulated in the proximal tubules and crescentic glomeruli of the kidneys of patients with renal AAV. Immunostaining showed that activin A protein also was present in the proximal tubules, crescentic glomeruli, and macrophages infiltrating into the interstitium in the kidneys of patients with renal AAV. These data suggested that urinary activin A concentration reflects renal inflammation and tubular damage in AAV and may be a useful biomarker for monitoring renal AAV.

AIM Sodium-glucose cotransporter 2 (SGLT2) inhibitors are an antihyperglycemic drug with diuretic properties. We recently reported that an SGLT2 inhibitor ameliorated extracellular fluid expansion with a transient increase in urinary Na+ excretion. However, the effects of SGLT2 inhibitors on fluid distribution in comparison to conventional diuretics remain unclear. METHODS Forty chronic kidney disease patients with fluid retention (average estimated glomerular filtration rate 29.2 ± 3.2 mL/min per 1.73 m2 ) were divided into the SGLT2 inhibitor dapagliflozin (DAPA), loop diuretic furosemide (FR) and vasopressin V2 receptor antagonist tolvaptan (TLV). The body fluid volume was measured on days 0 and 7 using a bioimpedance analysis device. RESULTS In all three groups, body weight was significantly and similarly decreased, and urine volume numerically increased for 7 days. Bioimpedance analysis showed that the changes in intracellular water were similar, but that there were significant changes in the extracellular water (ECW) (DAPA -8.4 ± 1.7, FR -12.5 ± 1.3, TLV -7.4 ± 1.5%, P = 0.048). As a result, the change in the ratio of ECW to total body water in the DAPA group was significantly smaller than that in the FR group, but numerically larger than that in the TLV group (DAPA -1.5 ± 0.5, FR -3.6 ± 0.5, TLV -0.5 ± 0.4%, P

Renal impairment (RI) is a common complication of multiple myeloma (MM) that significantly affects treatment efficacy and mortality. However, no useful biomarkers for early detection of renal damage in MM exist. Reports indicate that activin A, a multifunctional cytokine of the TGF-β superfamily, is involved in the development and progression of various kidney diseases. In the present study, we measured urinary activin A levels in patients with newly diagnosed MM (NDMM) (n=41), smoldering MM (SMM) (n=10), and monoclonal gammopathy of undetermined significance (MGUS) (n=28), including monoclonal gammopathy of renal significance (MGRS), and assessed the correlation between urinary activin A and several clinical parameters. Urinary activin A, undetectable in healthy volunteers, was significantly increased in NDMM patients but not in patients with SMM and MGUS (97.3, 25.0, and 6.61 mg/gCr, respectively, P

Objective: We aimed to describe the clinical characteristics and treatment course of hypertrophic pachymeningitis (HPM) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Methods: We retrospectively analysed 15 patients (11 men and four women). HPM was diagnosed based on thickening and enhancing of the brain and/or spinal dura mater on gadolinium-enhanced magnetic resonance imaging (MRI) T1 sequence. Results: The median age at HPM onset was 60 years. Headache and cranial nerve impairment were observed in 14 and 10 patients, respectively. Otitis media and/or mastoiditis were found as complications of AAV in 11 patients. Fourteen patients were classified as having granulomatosis with polyangiitis (GPA). Single-positive myeloperoxidase-ANCA, single-positive proteinase 3-ANCA, and double-positive ANCA were identified in seven patients, five patients, and one patient, respectively. With MRI, thickening of the dura mater in the cranial fossa and tentorium cerebelli was found in 10 and eight patients, respectively. For remission induction, all patients were treated with corticosteroids, and immunosuppressants were added in 10 patients. Dura mater thickening partially improved in all patients, and cranial neuropathy completely remitted in eight patients. In a median follow-up of 43 months, four patients had HPM relapse and underwent reinduction therapy. All six patients treated with cyclophosphamide at initial therapy did not relapse. Conclusions: HPM was mostly associated with patients with GPA with otitis media and/or mastoiditis having either type of ANCA serology. Treatment with corticosteroids with or without immunosuppressants was effective. However, HPM relapse occasionally occurred, especially when cyclophosphamide was not used in initial treatment.

Tubulogenesis, the organization of epithelial cells into tubular structures, is an essential step during renal organogenesis as well as during the regeneration process of renal tubules after injury. In the present study, endothelial cell-derived factors that modulate tubule formation were examined using an in vitro human tubulogenesis system. When human renal proximal tubular epithelial cells (RPTECs) were cultured in gels, tubular structures with lumens were induced in the presence of hepatocyte growth factor (HGF). Aquaporin 1 was localized in the apical membrane of these tubular structures, suggesting that these structures are morphologically equivalent to renal tubules in vivo. HGF-induced tubule formation was significantly enhanced when co-cultured with human umbilical vein endothelial cells (HUVECs) or in the presence of HUVEC-conditioned medium (HUVEC-CM). Co-culture with HUVECs did not induce tubular structures in the absence of HGF. A phospho-receptor tyrosine kinase array revealed that HUVEC-CM markedly enhanced phosphorylation of Ret, glial cell-derived neurotrophic factor (GDNF) receptor, in HGF-induced tubular structures compared to those without HUVEC-CM. HUVECs produced GDNF, and RPTECs expressed both Ret and GDNF family receptor alpha1 (co-receptor). HGF-induced tubule formation was significantly enhanced by addition of GDNF. Interestingly, not only HGF but also GDNF significantly induced phosphorylation of the HGF receptor, Met. These data indicate that endothelial cell-derived GDNF potentiates the tubulogenic properties of HGF and may play a critical role in the epithelial-endothelial crosstalk during renal tubulogenesis as well as tubular regeneration after injury.

Aberrant expression of T helper cell (Th) cytokines is believed to play a central role in the pathogenesis of systemic lupus erythematosus (SLE). While the glomerulus is one of the major targets of lupus inflammation, little is known about the cytokine expression in glomeruli. The current study aimed to explore the profiles of Th cytokine gene expressions in isolated glomeruli of lupus-prone mice.Glomeruli were purified from lupus-prone MRL/lpr mice using the magnetic microbead method. Expressions of cytokine genes representing the Th subset and FoxP3 were examined using real-time polymerase chain reaction. Serum levels of these cytokines were also measured by enzyme-linked immunosorbent assay. MRL/n mice were used as controls. Histologic glomerular damages were scored semiquantitatively. To examine the role of TNF-α in glomerular damage, we administered etanercept, a TNF-α antagonist, into the subjects.Glomerular gene expressions of TNF-α in lpr mice increased with week postpartum and reached statistically significant levels at 16 weeks compared with those of the glomeruli from control mice. Expressions of IFN-γ, IL-4 and FoxP3 also increased, but the difference was not significant. There was a significant increase in serum levels of TNF-α, IFN-γ, and IL-17 and decrease in those of IL-4. Among the genes examined, TNF-α significantly correlated with glomerular damage score. Administration of etanercept did not affect glomerular cytokine expressions or proteinuria and failed to ameliorate histologic glomerular damages.Our data suggest that Th1 cytokines, especially TNF-α, are dominantly expressed in the glomeruli of lupus-prone mice, but its pathophysiological role remains unclear.

Hepatitis E is an acute self-limiting disease caused by hepatitis E virus (HEV). Recent reports show that HEV can induce chronic hepatitis or be reactivated in immunocompromised hosts. We report a 63-year-old woman with rheumatoid arthritis (RA) who developed hepatitis E during treatment with tocilizumab. Analysis of serially stocked serum samples confirmed that hepatitis was caused by primary infection with HEV and not by viral reactivation. Her liver function improved after discontinuing tocilizumab and remained within the normal range without reactivation of HEV for >5 years after restarting tocilizumab. We also reviewed the published cases of hepatitis E that developed during RA treatment.

Objectives The objective of this study was to test the correlation of urinary podocyte number (U-Pod) and urinary podocalyxin levels (U-PCX) with histology of lupus nephritis. Methods This was an observational, cross-sectional study. Sixty-four patients were enrolled: 40 with lupus nephritis and 24 without lupus nephritis (12 lupus nephritis patients in complete remission and 12 systemic lupus erythematosus patients without lupus nephritis). Urine samples were collected before initiating treatment. U-Pod was determined by counting podocalyxin-positive cells, and U-PCX was measured by sandwich ELISA, normalized to urinary creatinine levels (U-Pod/Cr, U-PCX/Cr). Results Lupus nephritis patients showed significantly higher U-Pod/Cr and U-PCX/Cr compared with patients without lupus nephritis. U-Pod/Cr was high in proliferative lupus nephritis (class III±V/IV±V), especially in pure class IV (4.57 (2.02–16.75)), but low in pure class V (0.30 (0.00–0.71)). U-Pod/Cr showed a positive correlation with activity index ( r=0.50, P=0.0012) and was independently associated with cellular crescent formation. In contrast, U-PCX/Cr was high in both proliferative and membranous lupus nephritis. Receiver operating characteristic analysis revealed significant correlation of U-Pod/Cr with pure class IV, class IV±V and cellular crescent formation, and the combined values of U-Pod/Cr and U-PCX/Cr were shown to be associated with pure class V. Conclusions U-Pod/Cr and U-PCX/Cr correlate with histological features of lupus nephritis.

Sestrin 2, initially identified as a p53 target protein, accumulates in cells exposed to stress and inhibits mammalian target of rapamycin (mTOR) signaling. In normal rat kidneys, sestrin 2 was selectively expressed in parietal epithelial cells (PECs), identified by the marker protein gene product 9.5. In adriamycin nephropathy, sestrin 2 expression decreased in PECs on day 14, together with increased expression of phosphorylated S6 ribosomal protein (P-S6RP), a downstream target of mTOR. Sestrin 2 expression was markedly decreased on day 42, coinciding with glomerulosclerosis and severe periglomerular fibrosis. In puromycin aminonucleoside nephropathy, decreased sestrin 2 expression, increased P-S6RP expression, and periglomerular fibrosis were observed on day 9, when massive proteinuria developed. These changes were transient and nearly normalized by day 28. In crescentic glomerulonephritis, sestrin 2 expression was not detected in cellular crescents, whereas P-S6RP increased. In conditionally immortalized cultured PECs, the forced downregulation of sestrin 2 by short hairpin RNA resulted in increased expression of P-S6RP and increased apoptosis. These data suggest that sestrin 2 is involved in PEC homeostasis by regulating the activity of mTOR. In addition, sestrin 2 could be a novel marker of PECs, and decreased expression of sestrin 2 might be a marker of PEC injury.

The kidney has the capacity for regeneration and repair after a variety of insults. Over the past few decades, factors that promote repair of the injured kidney have been extensively investigated. By using kidney injury animal models, the role of intrinsic and extrinsic growth factors, transcription factors, and extracellular matrix in this process has been examined. The identification of renal stem cells in the adult kidney as well as in the embryonic kidney is an active area of research. Cell populations expressing putative stem cell markers or possessing stem cell properties have been found in the tubules, interstitium, and glomeruli of the normal kidney. Cell therapies with bone marrow-derived hematopoietic stem cells, mesenchymal stem cells, endothelial progenitor cells, and amniotic fluid-derived stem cells have been highly effective for the treatment of acute or chronic renal failure in animals. Embryonic stem cells and induced pluripotent stem cells are also utilized for the construction of artificial kidneys or renal components. In this review, we highlight the advances in regenerative medicine for the kidney from the perspective of renotropic factors, renal stem/progenitor cells, and stem cell therapies and discuss the issues to be solved to realize regenerative therapy for kidney diseases in humans.

N-type Ca2+channels are densely distributed in sympathetic nerves that innervate renal tubules. However, the role of N-type Ca2+channels in renal fibrosis remains unknown. To address this issue, we examined the difference between the effects of amlodipine (an L-type Ca2+channel blocker) and cilnidipine (a dual L/N-type Ca2+channel blocker) on fibrotic changes using a rat unilateral ureteral obstruction (UUO) model. The expression of both L-type and N-type Ca2+channels was significantly upregulated in UUO kidneys compared with that in contralateral kidneys. There were no significant differences in mean blood pressure among the rats tested. Both amlodipine and cilnidipine significantly attenuated fibrotic changes in UUO kidneys. The antifibrotic effect of cilnidipine was more potent than that of amlodipine. Amlodipine as well as cilnidipine reduced type III collagen deposition, α-smooth muscle actin (α-SMA) expression, and interstitial cell proliferation. In addition, cilnidipine significantly reduced deposition of type I collagen and macrophage infiltration in UUO kidneys. With the use of in vivo bromodeoxyuridine labeling, label-retaining cells (LRCs) were identified as a population of tubular cells that participate in epithelial-mesenchymal transition after UUO. Some LRCs migrated into the interstitium, expressed α-SMA and vimentin, and produced several extracellular matrixes in UUO kidneys. The number of interstitial LRCs was significantly decreased by cilnidipine but not amlodipine. These data suggest that N-type Ca2+channels contribute to multiple steps of renal fibrosis, and its blockade may thus be a useful therapeutic approach for prevention of renal fibrosis.

Objectives: In this study, we aimed to assess the effect of combination of proliferative and membranous lesions (Class III + V or IV + V) on renal outcomes as an independent category distinct from Class III and IV. Methods: We retrospectively analyzed 103 Japanese patients (14 male and 89 female) with Class III/IV LN, with or without Class V, who underwent renal biopsy and were treated at our institution. Renal endpoint was defined as doubling of serum creatinine or end-stage renal disease (ESRD). Results: The number of patients in each group was as follows: pure Class III/IV, 81 patients and mixed Class III/IV + V, 22 patients. During a median follow-up period of 125.0 months, 10 patients developed renal endpoint: five had Class III/IV LN and five had a combination of Class III/IV + V. Kaplan–Meier analyses demonstrated that patients with mixed Class III/IV + V LN had significantly poorer renal outcomes than patients with Class III/IV LN. Multivariate Cox regression analyses identified serum creatinine, active and chronic lesions (A/C), and mixed Class III/IV + V) as independent risk factors for poor renal outcomes. Conclusions: This study demonstrated a combination of proliferative and membranous LN (ISN/RPS Class III/IV + V) predicts poor renal outcomes.

Castleman's disease is a benign lymphoproliferative disorder in which interleukin-6 (IL-6), a pleiotropic proinflammatory cytokine, is thought to play a pathogenetic role. Presented is the case of a 72-year-old man with Castleman's disease who exhibited progressive renal dysfunction with proteinuria. Renal biopsy revealed mesangial hypercellularity and matrix expansion in most glomeruli and peritubular inflammatory cell infiltration. Immunofluorescence studies showed intense deposition of IgG in a granular pattern along the glomerular basement membrane. Histological features were compatible with membranoproliferative glomerulonephritis accompanied by interstitial inflammatory cell infiltration. Immunohistological analysis showed that IL-6 was abundantly expressed by tubular cells and interstitial macrophages, suggesting involvement of IL-6 in the renal injury. As a result of administration of tocilizumab, a humanized anti-IL-6 receptor antibody, the patient experienced clinical and biochemical improvement of Castleman's disease, including marked reduction of proteinuria and stabilization of renal function. These findings suggest the efficacy of tocilizumab against Castleman's disease and its renal complications.

Renal proximal tubular epithelium can regenerate after various insults. To examine whether the tubular repair process is regulated by surrounding peritubular capillaries, we established an in vitro human tubulogenesis model that mimics in vivo tubular regeneration after injury. In this model, HGF, a potent renotropic factor, dose dependently induced tubular structures in human renal proximal tubular epithelial cells cultured in gels. Consistent with regenerating tubular cells after injury, HGF-induced tubular structures expressed a developmental gene, Pax-2, and a mesenchymal marker, vimentin, and formed a lumen with aquaporin-1 expression. Electron microscopic analysis showed the presence of microvilli on the apical site of the lumen, suggesting that these structures are morphologically equivalent to renal tubules in vivo. When cocultured with human umbilical vein endothelial cells (HUVEC), HGF-induced tubular formation was significantly enhanced. This could not be reproduced by the addition of VEGF, basic FGF, or PDGF. Protein array revealed that HUVEC produced various matrix metalloproteinases (MMPs). The stimulatory effects of coculture with HUVEC or HUVEC-derived conditional medium were almost completely abolished by addition of the tissue inhibitor of metalloproteinase (TIMP)-1 or TIMP-2. These data suggest that endothelial cell-derived factors including MMPs play a critical role in tubulogenesis and imply a potential role of peritubular capillary endothelium as a source of factor(s) required for tubular recovery after injury.

Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) is a secretory protein that shares a structural similarity with IGFBP. Studies have shown that IGFBP-rP1 synergistically increases fibroblast growth with insulin and stimulates angiogenesis in tumor tissues. In this report, we examined the expression and function of IGFBP-rP1 in rheumatoid arthritis (RA). IGFBP-rP1 expression in synovial tissues was examined by reverse transcription-polymerase chain reaction (RT-PCR), real-time PCR, and immunohistochemical analysis. In vitro, IGFBP-rP1 expression was examined in synovial fibroblasts established from rheumatoid synovium (RASFs) by RT-PCR, Western blot, and immunostaining. The effect of IGFBP-rP1 small interfering RNA (siRNA) on RASF proliferation was assessed by alamarBlue assay. IGFBP-rP1 mRNA was detected by RT-PCR in all synovial tissues from RA and OA patients. In immunohistochemical analysis, IGFBP-rP1 was mainly expressed in synovial cells in the lining layers and endothelial cells in the sublining layers of RA synovium. In vitro, constitutive expression of IGFBP-rP1 in RASFs was detected by RT-PCR, Western blot, and immunostaining. Treatment with IGFBP-rP1 siRNA induced a 26% decrease in RASF growth compared to control siRNA. A similar extent of growth-suppressive effect by IGFBP-rP1 siRNA was also observed when RASF proliferation was induced by TNF-α. Collectively, these data suggest that IGFBP-rP1 may regulate synovial fibroblast proliferation in RA.

While tumor necrosis factor (TNF) inhibitors have dramatically improved the clinical outcomes of rheumatoid arthritis (RA) in recent years, infectious complications are a serious concern. Adalimumab (ADA) is a newly-developed human monoclonal antibody against TNF-alpha. Here we report 2 cases of pneumocystis pneumonia (PCP) which developed in RA patients during ADA therapy. One patient is a 66-year-old woman who had a history of RA for 6 months. The patient was given ADA at 40 mg biweekly for her active arthritis which had been refractory to 6 mg/week of methotrexate (MTX), and 5 mg/day of prednisolone (PSL). One hundred and six days later, she was admitted to our hospital because of fever, cough, and dyspnea. Another patient is a 62-year-old man who had a history of RA for 3 years. Since his arthritis was so active even under the treatment with MTX (8 mg/week) and PSL (15 mg/day), the patient started to be given ADA at 40 mg biweekly. After 28 days, the patient was admitted to the hospital because of dyspnea. Chest roentgenogram and computed tomography revealed interstitial pneumonia in both patients. Beta-D-glucan levels were so high in their serum suggesting the diagnosis of PCP, which was confirmed by the detection of Pneumocystis jirovecii DNA in the sputa by polymerase chain reaction. The patients were immediately treated with sulfamethoxazole/trimethoprim and high-dose prednisolone, which successfully improved pneumonia, and they were discharged from the hospital on the 8(th) and 16(th) day, respectively. PCR and β-D-glucan were useful for the early diagnosis of PCP and lead to the timely induction of adequate treatment and the rescue of these patients.

Aim: Transforming growth factor-β (TGF-β) is involved in renal tubulointerstitial fibrosis. Recently, the ubiquitin proteasome system was shown to participate in the TGF-β signalling pathway. The aim of this study was to examine the effects of proteasome inhibitors on TGF-β-induced transformation of renal fibroblasts and tubular epithelial cells in vitro and on unilateral ureteral obstruction (UUO) in vivo. Methods: Rat renal fibroblasts NRK-49F cells and tubular epithelial cells, NRK-52E, were treated with TGF-β in the presence or absence of a proteasome inhibitor, MG132 or lactacystin. Rats were subjected to UUO and received MG132 i.p. for 7 days. Results: In cultured renal cells, both MG132 and lactacystin inhibited TGF-β-induced α-smooth muscle actin (α-SMA) protein expression according to both western blotting and immunofluorescent study results. MG132 also suppressed TGF-β-induced mRNA expression of α-SMA and upregulation of Smad-response element reporter activity. However, MG132 did not inhibit TGF-β-induced phosphorylation and nuclear translocation of Smad2. In contrast, MG132 increased the protein level of Smad co-repressor SnoN, demonstrating that SnoN is one of the target molecules by which MG132 blocks the TGF-β signalling pathway. Although the proteasome inhibitor suppressed TGF-β-induced transformation of cultured fibroblasts and tubular epithelial cells, MG132 treatment did not ameliorate tubulointerstitial fibrosis in the rat UUO model. Conclusion: Proteasome inhibitors attenuate TGF-β signalling by blocking Smad signal transduction in vitro, but do not inhibit renal interstitial fibrosis in vivo.

Aim: Nestin, an intermediate filament originally identified as a marker of neural progenitor cells, is transiently expressed in endothelial cells and tubuloepithelial cells during kidney development. However, in adult kidneys, podocytes are the only cells that express nestin. In this study, we examined tubulointerstitial nestin expression in human glomerulonephritis. Methods: Renal biopsy specimens obtained from 41 adult patients with immunoglobulin (Ig)A nephropathy were studied. Nestin expression was determined by immunohistochemical staining and estimated by digital image analysis. To identify the phenotype of nestin-positive cells, a double immunofluorescent study was performed for nestin and CD34 (a marker for endothelial cells) or α-smooth muscle actin (α-SMA, a marker for myofibroblasts). Results: In normal kidney, nestin expression was restricted to the podocytes and was not detected in tubular cells and tubulointerstitial cells. In contrast, increased nestin expression was observed at tubulointerstitial areas of IgA nephropathy. The degree of tubulointerstitial nestin expression was positively correlated with tubulointerstitial fibrosis (r = 0.546, P

Objective. IL-19 is a novel cytokine of the IL-10 family. In this study, we sought to examine whether IL-19 plays a role in the pathogenesis of RA. Methods. Expression of IL-19, IL-20 receptor 1 (IL-20R1) and IL-20R2 was examined by RT-PCR and immunohistochemical analysis in rheumatoid synovium. The effects of IL-19 on synovial cells established from rheumatoid synovium (RASCs), with regard to IL-6 production and signal transducers and activators of transcription3 (STAT3) activation, were examined by ELISA and western blot analysis, respectively. The effect of IL-19 on RASC apoptosis was examined by Hoechst staining, flow cytometry analysis of annexin V binding and caspase-3 activity. Results. IL-19, IL-20R1 and IL-20R2 mRNA were detected by RT-PCR in synovial tissues from RA patients. Immunohistochemical analysis showed IL-19 was predominantly expressed in the hyperplastic lining layers of RA synovial tissues. The majority of IL-19-positive cells were vimentin-positive and CD68-positive synovial cells, serving as markers of fibroblasts and macrophages, respectively. IL-20R1 and IL-20R2 (IL-20Rs) were expressed in both the lining and sublining layers of RA synovium. In RASC, IL-19 was induced by lipopolysaccharide stimulation and constitutive expression of IL-20Rs was observed, suggesting IL-19 has an autocrine action. In terms of this function, IL-19 induced STAT3 activation and increased IL-6 production by RASC above the medium control. Moreover, IL-19 significantly reduced RASC apoptosis induced by serum starvation. Conclusions. These data suggest that IL-19, produced by synovial cells, promotes joint inflammation in RA by inducing IL-6 production and decreasing synovial cell apoptosis.

Lupus nephritis is a life-threatening complication of systemic lupus erythematosus (SLE). Various growth factors, cytokines, and chemokines are implicated in the development of SLE. However, the pathophysiological processes involved in the development of lupus nephritis still remain unclear. In this study, we examined the involvement of activin A, a member of the transforming growth factor β (TGF-β) superfamily, in the progression of renal damage in lupus-prone MRL- lpr mice. Activin A was not expressed in the kidneys of control MRL-MpJ mice but was detectable in perivascular infiltrating cluster of differentiation 68 (CD68)-positive cells in the kidneys of MRL- lpr mice. Urinary activin A, which was also absent in MRL-MpJ mice, was detectable in MRL- lpr mice from 16 wk onward. Urinary activin A levels were significantly correlated with the number of perivascular inflammatory cell layers, the number of crescentic glomeruli, and the percentage of Elastica van Gieson (EVG)-positive fibrotic areas, but not with urinary protein levels or serum activin A. When activin action was blocked in vivo by the intraperitoneal administration of an activin antagonist, follistatin, the number of crescentic glomeruli, percentage of EVG-positive fibrotic areas, CD68-positive cell infiltration, and proteinuria were significantly reduced in a dose-dependent manner. These data suggest that infiltrating macrophage-derived activin A is involved in the progression of renal damage in MRL- lpr mice.

The kidney collecting duct system and the ureter derive from the ureteric bud, an outgrowth of the Wolffian duct. It is generally believed that glial cell–derived neurotrophic factor (GDNF) plays a critical role in this earliest stage of kidney development, but 30 to 50% of knockout mice that lack

The kidney is capable of regeneration. In response to a variety of insults, renal epithelial tubular cells dedifferentiate into an immature phenotype, proliferate, migrate to the injured area, and redifferentiate into mature polarized epithelial cells. In animal models of acute kidney injury induced by renal ischemia or renal toxins, various growth factors, transcription factors, chemokines, and extracellular matrix components have been demonstrated to be involved in the regeneration process. Recent research has suggested the existence of renal stem/progenitor cells in the kidney and their involvement in renal regeneration. In this review, we will focus on the mechanisms of tubular regeneration after kidney injury, particularly on label-retaining cells actively engaged in this process, and discuss their potential as targets of regenerative therapy for various kidney diseases.

Nestin is an intermediate filament protein originally identified in neuroepithelial stem cells. This cytoskeletal-associated protein is also expressed in some non-neuronal organs including renal tubular cells and glomerular endothelial cells during kidney development. Little is known, however, about nestin expression in the kidney during injury. In this study, we find nestin expression induced in renal tubular and interstitial myofibroblasts in the adult rat kidney following unilateral ureteral obstruction. The degree of nestin expression was well correlated with the degree of tubulointerstitial fibrosis. Immunohistochemical identification of specific nephron segments showed that nestin was primarily expressed by proximal tubules, partially by distal tubules and thick ascending limbs of Henle but not by collecting ducts. The nestin-positive tubular cells also expressed vimentin and heat-shock protein 47 (HSP47) suggesting these cells reverted to a mesenchymal phenotype. Not all vimentin- or HSP-expressing cells expressed nestin; however, suggesting that nestin is distinct from these conventional mesenchymal markers. Nestin expression was also found associated with phenotypical changes in cultured renal cells induced by hypoxia or transforming growth factor-beta. Nestin expression was located in hypoxic regions of the kidney with an obstructed ureter. Our results indicate that nestin could be a novel marker for tubulointerstitial injury.

Renal progenitor tubular cells (label-retaining cells [LRC]) were recently identified in normal kidneys by in vivo bromodeoxyuridine (BrdU) labeling. This study was conducted to examine the behavior of LRC in renal fibrosis. BrdU was injected intraperitoneally into normal rats daily for 7 d. After a 2-wk chase period, unilateral ureteral obstruction (UUO) was induced in these rats. In normal and contralateral kidneys, LRC were observed scattering among tubular epithelial cells. After UUO, the number of the LRC significantly increased, and most of them were positive for proliferating cell nuclear antigen (PCNA). In contrast, PCNA+ cells lacking BrdU label were rarely observed. It is interesting that LRC were detected not only in tubules but also in the interstitium after UUO. Laminin staining showed that a number of the LRC were adjacent to the destroyed tubular basement membrane. Some tubules, including LRC, lost the expression of E-cadherin after UUO. A large number of cell populations expressed vimentin, heat shock protein 47, or alpha-smooth muscle actin in the UUO kidneys, and each population contained LRC. None of the LRC was positive for these fibroblastic markers in contralateral kidneys. When renal tubules from BrdU-treated rats were cultured in the gel, some cells protruded from the periphery of the tubules and migrated into the gel. Most of these cells were BrdU+. Neither the total content of BrdU in the kidneys nor the number of LRC in bone marrow significantly changed after UUO. Collectively, these results suggest that LRC is a cell population that proliferates, migrates, and transdifferentiates into fibroblast-like cells during renal fibrosis.