駒田 敬則

Recent evidence indicates ferroptosis is implicated in the pathophysiology of various liver diseases; however, the organ-specific regulation mechanism is poorly understood. Here, we demonstrate 7-dehydrocholesterol reductase (DHCR7), the terminal enzyme of cholesterol biosynthesis, as a regulator of ferroptosis in hepatocytes. Genetic and pharmacological inhibition (with AY9944) of DHCR7 suppress ferroptosis in human hepatocellular carcinoma Huh-7 cells. DHCR7 inhibition increases its substrate, 7-dehydrocholesterol (7-DHC). Furthermore, exogenous 7-DHC supplementation using hydroxypropyl β-cyclodextrin suppresses ferroptosis. A 7-DHC-derived oxysterol metabolite, 3β,5α-dihydroxycholest-7-en-6-one (DHCEO), is increased by the ferroptosis-inducer RSL-3 in DHCR7-deficient cells, suggesting that the ferroptosis-suppressive effect of DHCR7 inhibition is associated with the oxidation of 7-DHC. Electron spin resonance analysis reveals that 7-DHC functions as a radical trapping agent, thus protecting cells from ferroptosis. We further show that AY9944 inhibits hepatic ischemia-reperfusion injury, and genetic ablation of Dhcr7 prevents acetaminophen-induced acute liver failure in mice. These findings provide new insights into the regulatory mechanism of liver ferroptosis and suggest a potential therapeutic option for ferroptosis-related liver diseases.

Caspase-11 is an inflammatory caspase that triggers an inflammatory response by regulating non-canonical NLRP3 inflammasome activation. Although the deficiency of both caspase-11 and caspase-1, another inflammatory caspase that functions as an executor of the inflammasome, prevents the development of atherosclerosis, the effect of caspase-11 deficiency alone on the development of atherosclerosis has not been fully evaluated. In the present study, we found that caspase-11 deficiency prevented the formation of the necrotic core, whereas it did not affect the development of atherosclerosis in Apoe-deficient mice. Notably, the infiltration of neutrophils into atherosclerotic lesions was attenuated by caspase-11 deficiency. RNA-seq analysis of stage-dependent expression of atherosclerotic lesions revealed that both upregulations of caspase-11 and neutrophil migration are common features of advanced atherosclerotic lesions. Furthermore, similar expression profiles were observed in unstable human plaque. These data suggest that caspase-11 regulates neutrophil recruitment and plaque destabilization in advanced atherosclerotic lesions.

Sepsis is a life-threatening syndrome, and its associated mortality is increased when cardiac dysfunction and damage (septic cardiomyopathy [SCM]) occur. Although inflammation is involved in the pathophysiology of SCM, the mechanism of how inflammation induces SCM in vivo has remained obscure. NLRP3 inflammasome is a critical component of the innate immune system that activates caspase-1 (Casp1) and causes the maturation of IL-1β and IL-18 as well as the processing of gasdermin D (GSDMD). Here, we investigated the role of the NLRP3 inflammasome in a murine model of lipopolysaccharide (LPS)-induced SCM. LPS injection induced cardiac dysfunction, damage, and lethality, which was significantly prevented in NLRP3-/- mice, compared to wild-type (WT) mice. LPS injection upregulated mRNA levels of inflammatory cytokines (Il6, Tnfa, and Ifng) in the heart, liver, and spleen of WT mice, and this upregulation was prevented in NLRP3-/- mice. LPS injection increased plasma levels of inflammatory cytokines (IL-1β, IL-18, and TNF-α) in WT mice, and this increase was markedly inhibited in NLRP3-/- mice. LPS-induced SCM was also prevented in Casp1/11-/- mice, but not in Casp11mt, IL-1β-/-, IL-1α-/-, or GSDMD-/- mice. Notably, LPS-induced SCM was apparently prevented in IL-1β-/- mice transduced with adeno-associated virus vector expressing IL-18 binding protein (IL-18BP). Furthermore, splenectomy, irradiation, or macrophage depletion alleviated LPS-induced SCM. Our findings demonstrate that the cross-regulation of NLRP3 inflammasome-driven IL-1β and IL-18 contributes to the pathophysiology of SCM and provide new insights into the mechanism underlying the pathogenesis of SCM.

Rhabdomyolysis is a severe condition that commonly leads to acute kidney injury (AKI). While double-stranded DNA (dsDNA) released from injured muscle can be involved in its pathogenesis, the exact mechanism of how dsDNA contributes to rhabdomyolysis-induced AKI (RIAKI) remains obscure. A dsDNA sensor, absent in melanoma 2 (AIM2), forms an inflammasome and induces gasdermin D (GSDMD) cleavage resulting in inflammatory cell death known as pyroptosis. In this study using a mouse model of RIAKI, we found that Aim2-deficiency led to massive macrophage accumulation resulting in delayed functional recovery and perpetuating fibrosis in the kidney. While Aim2-deficiency compromised RIAKI-induced kidney macrophage pyroptosis, it unexpectedly accelerated aberrant inflammation as demonstrated by CXCR3+CD206+ macrophage accumulation and activation of TBK1-IRF3/NF-κB. Kidney macrophages with intact AIM2 underwent swift pyroptosis without IL-1β release in response to dsDNA. On the other hand, dsDNA-induced Aim2-deficient macrophages escaped from swift pyroptotic elimination and instead engaged STING-TBK1-IRF3/NF-κB signalling, leading to aggravated inflammatory phenotypes. Collectively, these findings shed light on a hitherto unknown immunoregulatory function of macrophage pyroptosis. dsDNA-induced rapid macrophage cell death potentially serves as an anti-inflammatory program and determines the healing process of RIAKI.

Cryopyrin-associated periodic syndrome (CAPS) is an autoinflammatory syndrome caused by mutations of NLRP3 gene encoding cryopyrin. Familial cold autoinflammatory syndrome, the mildest form of CAPS, is characterized by cold-induced inflammation induced by the overproduction of IL-1β. However, the molecular mechanism of how mutated NLRP3 causes inflammasome activation in CAPS remains unclear. Here, we found that CAPS-associated NLRP3 mutants form cryo-sensitive aggregates that function as a scaffold for inflammasome activation. Cold exposure promoted inflammasome assembly and subsequent IL-1β release triggered by mutated NLRP3. While K+ efflux was dispensable, Ca2+ was necessary for mutated NLRP3-mediated inflammasome assembly. Notably, Ca2+ influx was induced during mutated NLRP3-mediated inflammasome assembly. Furthermore, caspase-1 inhibition prevented Ca2+ influx and inflammasome assembly induced by the mutated NLRP3, suggesting a feed-forward Ca2+ influx loop triggered by mutated NLRP3. Thus, the mutated NLRP3 forms cryo-sensitive aggregates to promote inflammasome assembly distinct from canonical NLRP3 inflammasome activation.

Absent in melanoma-2 (AIM2) is an inflammasome-forming innate immune sensor for dsDNA but also exhibits inflammasome-independent functions such as restricting cellular proliferation. AIM2 is expressed in the kidney, but its localization and function are not fully characterized. In normal human glomeruli, AIM2 localized to podocytes. In patients with glomerulonephritis, AIM2 expression increased in CD44+-activated parietal epithelial cells within glomerular crescents. To explore AIM2 effects in glomerular disease, studies in Aim2 -/- mice were performed. Aim2-/- glomeruli showed reduced expression of Wilm tumor gene-1 (WT1), WT1-driven podocyte genes, and increased proliferation in outgrowth assays. In a nephrotoxic serum (NTS)-induced glomerulonephritis model, Aim2-/- (B6) mice exhibited more severe glomerular crescent formation, tubular injury, inflammation, and proteinuria compared with wild-type controls. Inflammasome activation markers were absent in both Aim2 -/- and wild-type kidneys, despite an increased inflammatory transcriptomic signature in Aim2 -/- mice. Aim2 -/- mice also demonstrated dysregulated cellular proliferation and an increase in CD44+ parietal epithelial cells during glomerulonephritis. The augmented inflammation and epithelial cell proliferation in Aim2 -/- (B6) mice was not due to genetic background, as Aim2 -/- (B6.129) mice demonstrated a similar phenotype during NTS glomerulonephritis. The AIM2-like receptor (ALR) locus was necessary for the inflammatory glomerulonephritis phenotype observed in Aim2 -/- mice, as NTS-treated ALR -/- mice displayed equal levels of injury as wild-type controls. Podocyte outgrowth from ALR -/- glomeruli was still increased, however, confirming that the ALR locus is dispensable for AIM2 effects on epithelial cell proliferation. These results identify a noncanonical role for AIM2 in suppressing inflammation and epithelial cell proliferation during glomerulonephritis.

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.

Calciprotein particles (CPPs) are nanoparticles composed of calcium phosphate crystals and fetuin-A and have been implicated in diseases associated with inflammation. In the current study, we investigated the molecular mechanisms underlying CPP-induced inflammation in mice. CPPs predominantly upregulated IL-1β and IL-1α and provided priming and activation signals for the NLRP3 inflammasome in murine macrophages. Pharmacological and genetic inhibition of the NLRP3 inflammasome revealed that CPPs induced the release of IL-1β and IL-1α via NLRP3 inflammasome-dependent and -independent mechanisms, respectively. CPPs also induced necrotic cell death, but gasdermin D was dispensable for CPP-induced IL-1β release and necrotic cell death. Although phagocytosis of CPPs was required for CPP-induced IL-1β/α release and necrotic cell death, lysosomal dysfunction and K+ efflux were mainly involved in CPP-induced NLRP3 inflammasome activation and subsequent IL-1β release but not in CPP-induced IL-1α release and necrotic cell death. In vivo experiments showed that CPP administration evoked acute inflammatory responses characterized by neutrophil accumulation via both IL-1β and IL-1α. In particular, CPP-induced neutrophil inflammation was mediated predominantly through an IL-1α-induced CXCL1/CXCR2 signaling pathway. These results provide new insights into the mechanism underlying CPP-induced inflammation and suggest that targeting both IL-1β and IL-1α is necessary to regulate the CPP-induced inflammatory response and to treat CPP-associated inflammatory disorders.

BACKGROUND: Platelets are critical mediators of vascular homeostasis and thrombosis, and also contribute to the development of inflammation. NLRP3 inflammasome is a cytosolic multi-protein complex that consists of NLRP3, ASC and caspase-1, and regulates IL-1β-mediated inflammation. METHOD AND RESULTS: Using two mouse models of thrombosis (i.e., occlusion of the middle cerebral artery and inferior vena cava), we found that thrombus formation was significantly enhanced in ASC-deficient (ASC-/-) mice, compared to that in wild-type (WT) and IL-1β-/- mice. ASC deficiency had no effects on blood coagulation parameters (i.e., prothrombin time [PT] and activated partial thromboplastin time [APTT]). Platelets from WT mice express ASC, but neither NLRP3 nor caspase-1. ASC deficiency significantly enhanced the expression of P-selectin and GPIIb/IIIa in response to a GPVI agonist (collagen-related peptide [CRP]), but not to thrombin, in platelets. CRP induced ASC speck formation in WT platelets. ASC deficiency also enhanced cytosolic Ca2+ elevation and phosphorylation of ERK1/2 and Akt in platelets. CONCLUSION: Our results demonstrate that ASC negatively regulates GPVI signaling in platelets and enhances thrombus formation, independent of NLRP3 inflammasome and IL-1β, and provide novel insights into the link between inflammation and thrombosis.

Intestinal ischemia/reperfusion (I/R) injury is a life-threatening complication that leads to inflammation and remote organ damage. The NLRP3 inflammasome regulates the caspase-1-dependent release of IL-1β, an early mediator of inflammation after I/R injury. In this study, we investigated the role of the NLRP3 inflammasome in mice with intestinal I/R injury. Deficiency of NLRP3, ASC, caspase-1/11, or IL-1β prolonged survival after intestinal I/R injury, but neither NLRP3 nor caspase-1/11 deficiency affected intestinal inflammation. Intestinal I/R injury caused acute lung injury (ALI) characterized by inflammation, reactive oxygen species generation, and vascular permeability, which was markedly improved by NLRP3 deficiency. Bone marrow chimeric experiments showed that NLRP3 in non-bone marrow-derived cells was the main contributor to development of intestinal I/R-induced ALI. The NLRP3 inflammasome in lung vascular endothelial cells is thought to be important to lung vascular permeability. Using mass spectrometry, we identified intestinal I/R-derived lipid mediators that enhanced NLRP3 inflammasome activation in lung vascular endothelial cells. Finally, we confirmed that serum levels of these lipid mediators were elevated in patients with intestinal ischemia. To our knowledge, these findings provide new insights into the mechanism underlying intestinal I/R-induced ALI and suggest that endothelial NLRP3 inflammasome-driven IL-1β is a novel potential target for treating and preventing this disorder.

Although the intimate linkage between hypoxia and inflammation is well known, the mechanism underlying this linkage has not been fully understood. Nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is an intracellular multiprotein complex that regulates interleukin-1β (IL-1β) secretion and pyroptosis, and is implicated in the pathogenesis of sterile inflammatory diseases. Here, we investigated the regulatory mechanism of NLRP3 inflammasome activation in response to hypoxia in macrophages. Severe hypoxia (0.1% O2 ) induced the processing of pro-IL-1β, pro-caspase-1, and gasdermin D, as well as the release of IL-1β and lactate dehydrogenase in lipopolysaccharide (LPS)-primed murine macrophages, indicating that hypoxia induces NLRP3 inflammasome-driven inflammation and pyroptosis. NLRP3 deficiency and a specific caspase-1 blockade inhibited hypoxia-induced IL-1β release. Hypoxia-induced IL-1β release and cell death were augmented under glucose deprivation, and an addition of glucose in the media negatively regulated hypoxia-induced IL-1β release. Under hypoxia and glucose deprivation, hypoxia-induced glycolysis was not driven and subsequently, the intracellular adenosine triphosphates (ATPs) were depleted. Atomic absorption spectrometry analysis showed a reduction of intracellular K+ concentrations, indicating the K+ efflux occurring under hypoxia and glucose deprivation. Furthermore, hypoxia and glucose deprivation-induced IL-1β release was significantly prevented by inhibition of K+ efflux and KATP channel blockers. In vivo experiments further revealed that IL-1β production was increased in LPS-primed mice exposed to hypoxia (9.5% O2 ), which was prevented by a deficiency of NLRP3, an apoptosis-associated speck-like protein containing a caspase recruitment domain, and caspase-1. Our results demonstrate that NLRP3 inflammasome can sense intracellular energy crisis as a danger signal induced by hypoxia and glucose deprivation, and provide new insights into the mechanism underlying hypoxia-induced inflammation.

Acetaminophen (APAP) overdose is a common cause of drug-induced acute liver failure. Although hepatocyte cell death is considered to be the critical event in APAP-induced hepatotoxicity, the underlying mechanism remains unclear. Ferroptosis is a newly discovered type of cell death that is caused by a loss of cellular redox homeostasis. As glutathione (GSH) depletion triggers APAP-induced hepatotoxicity, we investigated the role of ferroptosis in a murine model of APAP-induced acute liver failure. APAP-induced hepatotoxicity (evaluated in terms of ALT, AST, and the histopathological score), lipid peroxidation (4-HNE and MDA), and upregulation of the ferroptosis maker PTGS2 mRNA were markedly prevented by the ferroptosis-specific inhibitor ferrostatin-1 (Fer-1). Fer-1 treatment also completely prevented mortality induced by high-dose APAP. Similarly, APAP-induced hepatotoxicity and lipid peroxidation were prevented by the iron chelator deferoxamine. Using mass spectrometry, we found that lipid peroxides derived from n-6 fatty acids, mainly arachidonic acid, were elevated by APAP, and that auto-oxidation is the predominant mechanism of APAP-derived lipid oxidation. APAP-induced hepatotoxicity was also prevented by genetic inhibition of acyl-CoA synthetase long-chain family member 4 or α-tocopherol supplementation. We found that ferroptosis is responsible for APAP-induced hepatocyte cell death. Our findings provide new insights into the mechanism of APAP-induced hepatotoxicity and suggest that ferroptosis is a potential therapeutic target for APAP-induced acute liver failure.

Cigarette smoking is a major risk factor for aortic aneurysm and dissection; however, no causative link between smoking and these aortic disorders has been proven. In the present study, we investigated the mechanism by which cigarette smoke affects vascular wall cells and found that cigarette smoke extract (CSE) induced a novel form of regulated cell death termed ferroptosis in VSMCs. CSE markedly induced cell death in A7r5 cells and primary rat VSMCs, but not in endothelial cells, which was completely inhibited by specific ferroptosis inhibitors (Ferrostatin-1 [Fer-1] and Liproxstatin-1) and an iron chelator (deferoxamine). CSE-induced VSMC death was partially inhibited by a GSH precursor (N-acetyl cysteine) and NADPH oxidase inhibitor (DPI), but not by inhibitors of pan-caspases (Z-VAD), caspase-1 (Z-YVAD), or necroptosis (Necrostatin-1). CSE also upregulated IL-1β, IL-6, TNF-α, MMP-2, MMP-9, and TIMP-1 in A7r5 cells, which was inhibited by Fer-1. Furthermore, CSE induced the upregulation of Ptgs2 mRNA, lipid peroxidation, and intracellular GSH depletion, which are key features of ferroptosis. VSMC ferroptosis was induced by acrolein and methyl vinyl ketone, major constituents of CSE. Furthermore, CSE caused medial VSMC loss in ex vivo aortas. Electron microscopy analysis showed mitochondrial damage and fragmentation in medial VSMCs of CSE-treated aortas. All of these manifestations were partially restored by Fer-1. These findings demonstrate that ferroptosis is responsible for CSE-induced VSMC death and suggest that ferroptosis is a potential therapeutic target for preventing aortic aneurysm and dissection.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) injury is a life-threatening complication that leads to inflammation and remote organ damage. However, the underlying mechanism is not yet fully understood. Toll-like receptor 5 (TLR5) is highly expressed in mucosa and recognizes flagellin, the main component of the bacterial flagella. Here, we investigated the role of TLR5 in inflammation and tissue damage after intestinal I/R injury using TLR5-deficient mice. METHODS AND RESULTS: Intestinal levels of TLR5 mRNA and flagellin protein were elevated in wild-type mice subjected to intestinal I/R. Although TLR5 deficiency had no effect on intestinal flagellin levels, it significantly attenuated intestinal injury and inflammatory responses after intestinal I/R. TLR5 deficiency also markedly improved survival in mice after intestinal I/R injury. In wild-type mice, intestinal I/R injury induced remote organ damage, particularly in the lung, which was attenuated by TLR5 deficiency. Furthermore, TLR5 deficiency prevented lung inflammatory responses and vascular permeability after intestinal I/R injury. CONCLUSION: These findings demonstrate a novel role of TLR5 and provide new insights into the mechanism underlying inflammation and tissue damage after intestinal I/R injury.

Inflammation plays an important role in the development of obesity and metabolic disorders; however, it has not been fully understood how inflammation occurs and is regulated in their pathogenesis. Low-molecular mass protein-7 (LMP7) is a proteolytic subunit of the immunoproteasome that shapes the repertoire of antigenic peptides on major histocompatibility complex class I molecule. In this study, we investigated the role of LMP7 in the development of obesity and metabolic disorders using LMP7-deficient mice. LMP7 deficiency conveyed resistant to obesity, and improved glucose intolerance and insulin sensitivity in mice fed with high-fat diet (HFD). LMP7 deficiency decreased pancreatic lipase expression, increased fecal lipid contents, and inhibited the increase of plasma triglyceride levels upon oral oil administration or HFD feeding. Using bone marrow-transferred chimeric mice, we found that LMP7 in both bone marrow-and non-bone marrow-derived cells contributes to the development of HFD-induced obesity. LMP7 deficiency decreased inflammatory responses such as macrophage infiltration and chemokine expression while it increased serum adiponection levels. These findings demonstrate a novel role for LMP7 and provide new insights into the mechanisms underlying inflammation in the pathophysiology of obesity and metabolic disorders.

Rhabdomyolysis is one of the main causes of community-acquired acute kidney injury (AKI). Although inflammation is involved in the pathogenesis of rhabdomyolysis-induced AKI (RIAKI), little is known about the mechanism that triggers inflammation during RIAKI. Recent evidence has indicated that sterile inflammation triggered by tissue injury can be mediated through multiprotein complexes called the inflammasomes. Therefore, we investigated the role of NLRP3 inflammasomes in the pathogenesis of RIAKI using a glycerol-induced murine rhabdomyolysis model. Inflammasomerelated molecules were upregulated in the kidney of RIAKI. Renal tubular injury and dysfunction preceded leukocyte infiltration into the kidney during the early phase of RIAKI, and they were markedly attenuated in mice deficient in NLRP3, ASC, caspase-1, and interleukin (IL)-1 beta compared with those in wild-type mice. No difference in leukocyte infiltration was observed between wild-type and NLRP3-deficient mice. Furthermore, NLRP3 deficiency strikingly suppressed the expression of renal injury markers and inflammatory cytokines and apoptosis of renal tubular cells. These results demonstrated that NLRP3 inflammasomes contribute to inflammation, apoptosis, and tissue injury during the early phase of RIAKI and provide new insights into the mechanism underlying the pathogenesis of RIAKI.

Inflammation plays a crucial role in the pathophysiologicat characteristics of chronic kidney disease; however, the inflammatory mechanisms underlying the chronic kidney disease process remain unclear. Recent evidence indicates that sterile inflammation triggered by tissue injury is mediated through a muttiprotein complex called the inflammasome. Therefore, we investigated the role of the inflammasome in the development of chronic kidney disease using a murine unilateral ureteral obstruction (UUO) model. Inflammasome-related molecules were up-regulated in the kidney after UUO. Apoptosis-associated speck-like protein containing a caspase recruitment domain deficiency significantly reduced inflammatory responses, such as inflammatory cell infiltration and cytokine expression, and improved subsequent renal injury and fibrosis. Furthermore, apoptosis-associated speck-like protein containing a caspase recruitment domain was specifically up-regulated in collecting duct (CD) epithelial cells of the UUO-treated kidney. In vitro experiments showed that extracellular adenosine triphosphate (ATP) induced inflammasome activation in CD epithelial cells through P2X(7)-potassium efflux and reactive oxygen species dependent pathways. These results demonstrate the molecular basis for the inflammatory response in the process of chronic kidney disease and suggest the CD inflammasome as a potential therapeutic target for preventing chronic kidney disease progression.

Mixed cryoglobulinemia is occasionally seen in patients with hepatitis B virus (HBV) infection. This report presents the case of a quiescent HBV carrier who had type II mixed cryoglobulinemia, protracted purpura, ulcerative skin lesions and advanced chronic kidney disease. The cutaneous manifestations of the patient improved along with a decrease in the serum cryoglobulin and HBV-deoxyribonucleic acid levels following the initiation of oral entecavir in combination with plasmapheresis. However, the patient ultimately required prednisolone due to the limited benefits of these treatments. We also discuss various concerns regarding steroid treatment in patients with mixed cryoglobulinemia complicated by HBV infection.

We herein report the case of a 75-year-old man who developed an increased serum creatinine level (4.93 mg/dL) and oliguria with massive proteinuria (7.14 g/day) on the second day after a single oral administration of high-dose (56 mg) minodronate. The histology of a renal biopsy showed one area of glomerular sclerosis among 20 glomeruli with global foot process effacement of podocytes and mild infiltration of lymphocytes and eosinophils into the interstitial space. Acute kidney injury in nephrotic syndrome due to focal segmental glomerular sclerosis induced by minodronate was diagnosed. Following cessation of minodronate without the administration of immunosuppressive agents, the patient's renal function and proteinuria markedly improved.

We herein report the case of a 17-year-old man who developed an increased plasma creatinine level (11.1 mg/dL) and oliguria with massive proteinuria (27.3 g/day) four weeks after an abraded wound to his right knee. The histology of the renal biopsy specimens showed diffuse endocapillary proliferative glomerulonephritis with the deposition of nephritis-associated plasmin receptor in the glomerulus. A case of acute kidney injury due to nephrotic syndrome caused by acute post-streptococcal glomerulonephritis was diagnosed. His renal function and proteinuria were improved with supportive care, including hemodialysis, without the administration of immunosuppressive agents. © 2013 The Japanese Society of Internal Medicine.

BACKGROUND: Klotho is a single-pass transmembrane protein, which appears to be implicated in aging. The purpose of the present study was to characterize the relationship between the soluble Klotho level and renal function in patients with various degrees of chronic kidney disease (CKD). METHODS: The levels of soluble Klotho in the serum and urine obtained from one hundred thirty-one CKD patients were determined by a sandwich enzyme-linked immunosorbent assay system. RESULTS: The amount of urinary excreted Klotho during the 24 hr period ranged from 1.6 to 5178 ng/day (median 427 ng/day; interquartile range [IR] 56.8-1293.1), and the serum Klotho concentration ranged from 163.9 to 2123.7 pg/ml (median 759.7 pg/ml; IR 579.5-1069.1). The estimated glomerular filtration rate (eGFR) was significantly correlated with the log-transformed values of the amount of 24 hr urinary excreted Klotho (r = 0.407, p < 0.01) and the serum Klotho levels (r = 0.232, p < 0.01). However, a stepwise multiple regression analysis identified eGFR to be a variable independently associated only with the log-transformed value of the amount of 24-hr urinary excreted Klotho but not with the log-transformed serum Klotho concentration. Despite the strong correlation between random urine protein-to-creatinine ratio and the 24 hr urinary protein excretion (r = 0.834, p < 0.01), a moderate linear association was observed between the log-transformed value of the amount of 24 hr urinary excreted Klotho and that of the urinary Klotho-to-creatinine ratio (Klotho/Cr) in random urine specimens (r = 0.726, p < 0.01). CONCLUSIONS: The amount of urinary Klotho, rather than the serum Klotho levels, should be linked to the magnitude of the functioning nephrons in CKD patients. The use of random urine Klotho/Cr as a surrogate for the amount of 24-hr urinary excreted Klotho needs to be evaluated more carefully.

Epstein-Barr virus (EBV) infection is common in adolescence, but fulminant infection is very rare. A 40-year-old man presented with high fever and sore throat. Symptoms, including cervical lymphadenopathy, jaundice, atypical lymphocytosis, respiratory distress and oliguria, suggested infectious mononucleosis with multiple organ failure that required mechanical ventilation and renal replacement therapy. Virus markers were consistent with primary EBV infection. Renal function was gradually improved by corticosteroid therapy. Renal biopsy revealed acute tubulointerstitial nephritis. In situ hybridizaion EBV-encoded RNA 1 did not show the presence of virus in the kidney, but acute kidney injury may be explained by cytotoxic/suppressor T lymphocyte infiltration,

Together with Nikkiso in Shizuoka, Japan, we developed a new method for measuring the rate of vascular access recirculation by the blood volume monitor. This measurement is performed via a method of dilution that employs a marker produced by rapid ultrafiltration using a dialysis machine. In this paper, we evaluate the reliability and safety of this machine, in vitro and in vivo. The safety of this method was evaluated by investigating hemolysis after rapid ultrafiltration. The measurement of free hemoglobin, potassium and haptoglobin in the circulating blood were performed before and after rapid ultrafiltration. No data was found to indicate hemolysis in vivo, detected by an increase in potassium or a decrease in haptoglobin. Evaluation of reliability in an experimental system was also performed on an in vitro recirculation system at a rate of 0, 10, 25, 50, and 70%. Almost all of the measured rates were within +/- 10% of the theoretical rate. We performed 20 hemodialysis experiments with vascular access recirculation applying this monitor and simultaneous urea and creatinine dilution methods, which were the recommended standard measurements for vascular recirculation. In 53 measurements of standard vascular shunts with no postural change, differences of the results between the monitor and both dilution methods were only 4.0% and 3.2%, respectively. Regression analysis showed a significant and positive correlation between them (P &lt; 0.0001). We conclude that this new method for measuring vascular access recirculation is applicable in terms of both accuracy and ease of operation.

We developed a new optical device (Nikkiso) to assess changes through blood volume monitoring (BVM) during hemodialysis and were able to determine the ideal levels in which changes in blood volume percentage (BV%) occur among hemodialysis patients in one hemodialysis center. We evaluated both the reliability of BVM and these ideal levels in a multicenter group. The purpose of this manuscript is to develop a navigating system to set dry weight in a variety of situations as the final goal. First, based on the obtained BVM (BV%(BVM)) measurements, the relationships between BV% and hematocrit (BV%(HT)) and between BV% and CRIT-LINE (BV%(CLM); Hema Metrics, Kaysville, UT, USA) were then evaluated. In 30 hemodialysis patients, there was a close correlation between both BV%(BVM) vs. BV%(HT) and BV%(BVM) vs. BV%(CLM) (n = 30, r = 0.967, P &lt; 0.001, and n = 36, r = 0.7867, P &lt; 0.001, respectively). Second, BV% data were obtained from 464 treatment cases performed on 26 subjects in one satellite hemodialysis center on patients whose body weight was deemed clinically suitable. The formulas for the levels of BV% (standardized by the percent change in body weight at the end of hemodialysis treatment: BW%end) were determined. Finally, we revalidated the reliability of the above levels. A total of 1126 measurements were performed on 201 patients whose body weights were deemed suitable in seven hemodialysis centers. New ideal levels were then recalculated. We therefore conclude that BVM is a sufficiently accurate method of monitoring BV% in hemodialysis treatment. Most well-controlled hemodialysis patients display the same pattern of BV%/BW%end. Monitoring BV% during hemodialysis is beneficial for determining dry weight (DW).

われわれは，透析患者の除水による循環血液量の変化をモニターする機器（Blood Volume Monitoring system：BVM）を日機装社（静岡）と共同開発し，多施設共同研究において臨床的にドライウエイト（DW）が適正と判断された患者の循環血液量の変化（BV％）の予想範囲を設定し，すでに報告した（Ther. Apher. Dial. in press）．本論文では，その予想範囲が適正な除水量設定に有用か否かを検討した．維持透析を行っている9施設の144名を対象とし，採血日を含む3回の透析日に，BVM搭載装置を用いて透析を行った．DWが適正と判断された患者のBV％予想範囲は，上限ライン：BV％/BW％後＝－0.437t－0.005 下限ライン：BV％/BW％後＝－0.245ln(t)－0.645t－0.810．BV％は循環血液量変化率，BW％後は透析による除水量の前体重に対する比率，tは透析時間（h）．今回の検討では，DW適正の可否を問わずに144例を抽出し，430データを集積した．プロトコール違反の94データを除外した336データを解析対象症例とした．各施設の判断によりDW適正と判断された230データで，BVMでも適正と判断された適正合致率は167データ（72.6％）であった．臨床的にDWを上げる必要があると判断された45データで，BVMでもDWを上げる必要があると判断されたのは10データ，逆に臨床的にDWを下げる必要があると判断された61データで，BVMでも下げる必要があると判断されたのは37データであった．その結果，BVMによる判定と臨床的判定の適合率は63.7％であった．不適合の原因としては，バスキュラーアクセスの再循環率（VARR），体位変換，体重増加量が1.0kg以下などであった．PWI（Plasma water index）による判定との適正合致率は71.6％で，適合率は58.0％であった．hANPによる判定との適正合致率は68.8％で，適合率は48.7％であった．循環血液量のモニターは，透析患者の除水設定管理の一助になり，われわれが設定したBV％予想範囲は臨床的にも妥当性が高いと考えられた．

Background : Oral adsorbent AST-120 reduces uremic toxins, such as indoxyl sulfate, and retards the progression of chronic kidney disease (CKD). The present study was conducted to elucidate the association between the progression of CKD and the combined effect of AST-120 and standard care based on diet therapy and medications such as ACE inhibitor and ARB Method : Retrospective analysis was performed using forty-four CKD patients (chronic glomerular nephritis 16, diabetic nephropathy 9, nephrosclerosis 13, and others 6) who were treated by AST-120 during the period from October, 2001 through December, 2004 and followed up for more than 6 months. The selection criteria were an estimated creatinine clearance (eCCr) of 30 mL/min or under at the initiation of treatment and a negative change in eCCr over time (ΔeCCr (mL/min/year)) before AST-120 treatment. The eCCr was calculated using the Cockcroft-Gault equation and the ΔeCCr was evaluated as a marker for the progression of chronic renal failure. Result : Overall ΔeCCr before and after AST-120 treatment significantly improved from -7.28 ± 6.33 to - 4.29±5.09(paired Wilcoxon test, p&lt 0.05). AST-120 led to greater +improvement of ΔeCCr in patients with an AeCCr of less than - 10 mL/min/year before AST-120 treatment and who had higher blood uric acid, urinary protein, and urinary specific gravity valves. Conclusion : This finding suggests that AST-120 treatment is effective in slowing the progression of chronic kidney disease, especially, in patients who exhibit a poor response to standard care.