Pathophysiological Mechanisms of Peritoneal Fibrosis and Peritoneal Membrane Dysfunction in Peritoneal Dialysis.

The characteristic feature of chronic peritoneal damage in peritoneal dialysis (PD) is a decline in ultrafiltration capacity associated with pathological fibrosis and angiogenesis. The pathogenesis of peritoneal fibrosis is attributed to bioincompatible factors of PD fluid and peritonitis. Uremia is associated with peritoneal membrane inflammation that affects fibrosis, neoangiogenesis, and baseline peritoneal membrane function. Net ultrafiltration volume is affected by capillary surface area, vasculopathy, peritoneal fibrosis, and lymphangiogenesis. Many inflammatory cytokines induce fibrogenic growth factors, with crosstalk between macrophages and fibroblasts. Transforming growth factor (TGF)-ß and vascular endothelial growth factor (VEGF)-A are the key mediators of fibrosis and angiogenesis, respectively. Bioincompatible factors of PD fluid upregulate TGF-ß expression by mesothelial cells that contributes to the development of fibrosis. Angiogenesis and lymphangiogenesis can progress during fibrosis via TGF-ß-VEGF-A/C pathways. Complement activation occurs in fungal peritonitis and progresses insidiously during PD. Analyses of the human peritoneal membrane have clarified the mechanisms by which encapsulating peritoneal sclerosis develops. Different effects of dialysates on the peritoneal membrane were also recognized, particularly in terms of vascular damage. Understanding the pathophysiologies of the peritoneal membrane will lead to preservation of peritoneal membrane function and improvements in technical survival, mortality, and quality of life for PD patients.

Granulocyte-colony stimulating factor producing cervical cancer with elevated levels of parathyroid hormone-related protein: a case report and literature review.

Systemic effects associated with hormones and cytokines secreted by tumor cells can cause paraneoplastic syndrome. Leukemoid reactions and hypercalcemia are relatively common manifestations of paraneoplastic syndrome. Here, we describe the case of a 90-year-old woman who presented with leukocytosis and hypercalcemia and was diagnosed with granulocyte-colony stimulating factor (G-CSF)-producing cervical cancer with elevated levels of parathyroid hormone-related protein (PTHrP). The patient visited our hospital complaining of general fatigue and anorexia. On admission, she presented with marked leukocytosis, hypercalcemia, and an increase in C-reactive protein level. On the basis of abdominal magnetic resonance imaging and histopathological examination, the patient was diagnosed with cervical cancer. Additional tests confirmed elevated plasma levels of G-CSF, PTHrP, and serum interleukin-6. Immunostaining of pathological specimens of the uterine cervix showed expression of G-CSF in tumor cells. The patient was diagnosed with G-CSF-producing cervical cancer accompanied by elevation of PTHrP levels. As a treatment for hypercalcemia, discontinuation of oral vitamin D derivative and administration of saline and elcatonin were ineffective, and therapeutic intervention with zoledronic acid hydrate was required. Considering the patient's advanced age, surgical resection of cervical cancer was not performed. She died from congestive heart failure approximately 3 months after hospitalization. This case was indicated to be a paraneoplastic syndrome in which G-CSF and PTHrP-induced leukocytosis and hypercalcemia. To the best of our knowledge, there have been no reports of G-CSF-producing cervical cancer with elevated PTHrP levels, and our case is the first report.

Increased RUNX3 expression mediates tumor-promoting ability of human breast cancer-associated fibroblasts.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are a major stromal component of human breast cancers and often promote tumor proliferation, progression and malignancy. We previously established an experimental CAF (exp-CAF) cell line equipped with a potent tumor-promoting ability. It was generated through prolonged incubation of immortalized human mammary fibroblasts with human breast cancer cells in a tumor xenograft mouse model. RESULTS: Herein, we found that the exp-CAFs highly express Runt-related transcription factor 3 (RUNX3), while counterpart fibroblasts do not. In breast cancer patients, the proportion of RUNX3-positive stromal fibroblast-like cells tends to be higher in cancerous regions than in non-cancerous regions. These findings suggest an association of RUNX3 with CAF characteristics in human breast cancers. To investigate the functional role of RUNX3 in CAFs, the exp-CAFs with or without shRNA-directed knockdown of RUNX3 were implanted with breast cancer cells subcutaneously in immunodeficient mice. Comparison of the resulting xenograft tumors revealed that tumor growth was significantly attenuated when RUNX3 expression was suppressed in the fibroblasts. Consistently, Ki-67 and CD31 immunohistochemical staining of the tumor sections indicated reduction of cancer cell proliferation and microvessel formation in the tumors formed with the RUNX3-suppressed exp-CAFs. CONCLUSION: These results suggest that increased RUNX3 expression could contribute to the tumor-promoting ability of CAFs through mediating cancer cell growth and neoangiogenesis in human breast tumors.

Pathophysiology of encapsulating peritoneal sclerosis: lessons from findings of the past three decades in Japan.

Encapsulating peritoneal sclerosis (EPS), a condition with a high mortality rate, is a serious complication of peritoneal dialysis (PD). In Japan, EPS became a central issue in the clinical setting during the mid-90s and the beginning of this century. However, following the introduction of biocompatible neutral PD solutions containing lower levels of glucose degradation products, the incidence and clinical severity of EPS has been greatly lessened. During the past three decades, the etiology of EPS has been elucidated by findings obtained by peritoneal biopsy, laparoscopy, and surgical intervention. Accumulating findings suggest the need for a paradigm change on the nature of EPS pathophysiology; notably, EPS appears not to reflect peritoneal sclerosis per se, but rather the formation of a neo-membrane as a biological reaction to peritoneal injury. This narrative review looks back on the history of EPS in Japan, and discusses EPS pathophysiology, the impact of neutral PD solution on peritoneal protection, and a future novel diagnostic approach, ultra-fine endoscope, for the identification of patients at high risk of EPS.

Peritoneal Expression of Membrane Complement Regulators Is Decreased in Peritoneal Dialysis Patients with Infected Peritonitis.

In peritoneal dialysis (PD) patients, fungi and Pseudomonas aeruginosa are considered important causative microorganisms for peritonitis with poor prognosis. Our objective was to explore expressions of membrane complement (C) regulators (CRegs) and tissue injuries in the peritoneum of patients with PD-related peritonitis, including fungal and Pseudomonas aeruginosa peritonitis. In peritoneal biopsy tissues obtained at PD catheter removal, we investigated the severity of peritonitis-associated peritoneal injuries and the expression of CRegs, CD46, CD55, and CD59 against peritoneal tissues without any episode of peritonitis. In addition, we evaluated peritoneal injuries among fungal and Pseudomonas aeruginosa-peritonitis (P1) and Gram-positive bacterial peritonitis (P2). We also observed deposition of C activation products such as activated C and C5b-9 and measured sC5b-9 in the PD fluid of patients. As a result, the severity of peritoneal injuries correlated inversely with the expression of peritoneal CRegs. Peritoneal CReg expression in peritonitis was significantly reduced compared to no peritonitis. Peritoneal injuries were more severe in P1 than in P2. CReg expression was further decreased and C5b-9 further increased in P1 than in P2. In conclusion, severe peritoneal injuries due to fungal and Pseudomonas aeruginosa-peritonitis decreased CReg expression and increased deposition of activated C3 and C5b-9 in the peritoneum, suggesting that peritonitis, particularly fungal and Pseudomonas aeruginosa-peritonitis, might induce susceptibility to further peritoneal injuries due to excessive C activation.

Malnutrition according to the GLIM criteria with kidney dysfunction is associated with increased mortality in hospitalized patients with cardiovascular disease: A retrospective cohort study.

BACKGROUND & AIMS: Cardiovascular disease (CVD) is a significant cause of mortality and rising healthcare costs, involving numerous chronic and nutritional risk. Although several studies have reported that malnutrition based on the Global Leadership Initiative on Malnutrition (GLIM) criteria is associated with mortality in patients with CVD, they have not evaluated this association in terms of malnutrition severity (moderate or severe). Furthermore, the relationship between malnutrition combined with renal dysfunction, a risk factor for death in CVD patients, and mortality has not been previously evaluated. Thus, we aimed to assess the association between malnutrition severity and mortality, as well as malnutrition status stratified by kidney function and mortality, in patients hospitalized due to CVD events. METHODS: This single-centre, retrospective cohort study included 621 patients with CVD aged ≥18 years admitted to Aichi Medical University between 2019 and 2020. The relationship between nutritional status based on the GLIM criteria (without malnutrition, moderate malnutrition, or severe malnutrition) and the incidence of all-cause mortality was evaluated by multivariable Cox proportional hazards models. RESULTS: Patients with moderate and severe malnutrition were significantly more prone to mortality than those without malnutrition (adjusted hazard ratio [HR] of patients without, with moderate, and with severe malnutrition: 1.00 [reference], 1.94 [1.12-3.35], and 2.63 [1.53-4.50], respectively). Furthermore, we found the highest all-cause mortality rate in patients with malnutrition and a lower estimated glomerular filtration rate (eGFR <30 mL/min/1.73 m2) (adjusted HR, 10.1; confidence interval, 3.90-26.4) than in patients without malnutrition and normal eGFR (eGFR ≥60 mL/min/1.73 m2). CONCLUSIONS: The present study indicated that malnutrition according to the GLIM criteria was associated with increased all-cause mortality in patients with CVD, and malnutrition associated with kidney dysfunction was associated with a higher risk of mortality. These findings provide clinically relevant information to identify high mortality risk in patients with CVD and highlight the need for giving careful attention to malnutrition with kidney dysfunction among patients with CVD.

Outcomes of Window Therapy with Carboplatin and Ifosfamide for Pediatric Osteosarcoma: A Case Series.

For the treatment of osteosarcoma, cisplatin (CDDP) can be substituted by carboplatin (CBDCA) to reduce toxicity. We report a single institution experience of CBDCA-based regimen. Two to three cycles of CBDCA + ifosfamide (IFO) therapy (window therapy) were administered as neoadjuvant therapy for osteosarcoma. Depending on the response of window therapy, the subsequent protocols were determined; for good responders, surgery is performed, and postoperative therapies with CBDCA + IFO, adriamycin (ADM) and high-dose methotrexate (MTX) were administered; for stable disease, the postoperative regimens were advanced before surgery, and the remaining amount of postoperative chemotherapy is deduced; for progressive disease, CBDCA-based regimen is changed to CDDP-based regimen. From 2009 to 2019, seven patients were treated with this protocol. During the window therapy, two patients (28.6%) were assessed as good responders and completed the regimen as planned. Four patients (57.1%) had stable disease, and the chemotherapy schedules were modified. One patient (14.2%) with progressive disease was shifted to the CDDP-based regimen. At final follow-up, four patients showed no evidence of disease and three patients died of the disease. Since the efficacy during window therapy was limited, a CBDCA-based regimen in the neoadjuvant setting was considered insufficient for performing adequate surgery.

Evaluation of the Immunological Response of Childhood Cancer Patients Treated with a Personalized Peptide Vaccine for Refractory Soft Tissue Tumor: A Four-Case Series.

This case series aimed to evaluate the peptide-specific immunoglobulin G (IgG) response, clinical effectiveness, and the safety of a personalized peptide vaccine (PPV) in four children with refractory solid cancer. Although the pre-vaccination IgG responses were suppressed, IgG levels against the vaccinated peptides after 12 vaccinations were increased in all three cases who received at least 12 vaccinations. Vaccination-related adverse effects were grade 1 injection-site local skin lesions. One patient, whose diagnosis was relapsed rhabdomyosarcoma, remains in sustained remission after 37 months. Although the pre-vaccination immune response in this patient was low, IgG levels against 2 of the 4 peptide vaccines were increased after the sixth vaccination, followed by a strong increase at the eighteenth vaccination against all 4 peptides, with a >100-fold increase vs. 2 peptides. The remaining three patients exhibited progressive disease and eventually died of their original cancer. The results of the current case series suggest that in cases of childhood solid tumors, when the tumor is controlled at the time of entry PPV may have some consolidation effect. Therefore, PPV could be a new immunotherapy modality for refractory childhood solid tumors.

Inhibition of Transglutaminase 2 Reduces Peritoneal Injury in a Chlorhexidine-Induced Peritoneal Fibrosis Model.

Long-term peritoneal dialysis (PD) is often associated with peritoneal dysfunction leading to withdrawal from PD. The characteristic pathologic features of peritoneal dysfunction are widely attributed to peritoneal fibrosis and angiogenesis. The detailed mechanisms remain unclear, and treatment targets in clinical settings have yet to be identified. We investigated transglutaminase 2 (TG2) as a possible novel therapeutic target for peritoneal injury. TG2 and fibrosis, inflammation, and angiogenesis were investigated in a chlorhexidine gluconate (CG)-induced model of peritoneal inflammation and fibrosis, representing a noninfectious model of PD-related peritonitis. Transforming growth factor (TGF)-ß type I receptor (TGFßR-I) inhibitor and TG2-knockout mice were used for TGF-ß and TG2 inhibition studies, respectively. Double immunostaining was performed to identify cells expressing TG2 and endothelial-mesenchymal transition (EndMT). In the rat CG model of peritoneal fibrosis, in situ TG2 activity and protein expression increased during the development of peritoneal fibrosis, as well as increases in peritoneal thickness and numbers of blood vessels and macrophages. TGFßR-I inhibitor suppressed TG2 activity and protein expression, as well as peritoneal fibrosis and angiogenesis. TGF-ß1 expression, peritoneal fibrosis, and angiogenesis were suppressed in TG2-knockout mice. TG2 activity was detected by α-smooth muscle actin-positive myofibroblasts, CD31-positive endothelial cells, and ED-1-positive macrophages. CD31-positive endothelial cells in the CG model were α-smooth muscle actin-positive, vimentin-positive, and vascular endothelial-cadherin-negative, suggesting EndMT. In the CG model, EndMT was suppressed in TG2-knockout mice. TG2 was involved in the interactive regulation of TGF-ß. As inhibition of TG2 reduced peritoneal fibrosis, angiogenesis, and inflammation associated with TGF-ß and vascular endothelial growth factor-A suppression, TG2 may provide a new therapeutic target for ameliorating peritoneal injuries in PD.

Serum and plasma levels of Ba, but not those of soluble C5b-9, might be affected by renal function in chronic kidney disease patients.

BACKGROUND: During the last few decades, pathogenic mechanisms associated with uncontrolled activation of the complement (C) system and development of anti-C agents have been closely investigated in the field of nephrology. The usefulness of some C products such as C5a and sC5b-9 for diagnostic and prognostic purposes remains controversial. On the other hand, decreased renal function is being observed in many patients with or without nephritis as a background factor in progressively aging societies. We therefore investigated whether renal function influenced the evaluation of various complement components and activation products. METHODS: To investigate the influence of renal function on evaluations of C3, C4, CH50, Ba, C5a and sC5b-9, 40 patients were retrospectively chosen from among 844 patients without active glomerulonephritis from 2009 to 2016. We measured plasma and serum levels of C3, C4, CH50, Ba, C5a and sC5b-9 using enzyme-linked immunosorbent assays and compared the findings with inulin clearance (Cin) as a marker of preserved renal function. RESULTS: Both plasma and serum levels of Ba correlated significantly with Cin, but other values did not. Compared with patients with Cin ≥ 60 or ≥ 30 mL/min/1.73 m2, plasma and serum levels of Ba were increased in patients with Cin decreased to < 60 or < 30 mL/min/1.73 m2, but levels of C5a and sC5b-9 were not. CONCLUSION: The influence of renal function might need to be considered when evaluating Ba, but not C5a and sC5b-9, in plasma and serum samples from chronic kidney disease patients.

Long non-coding RNA lnc-CHAF1B-3 promotes renal interstitial fibrosis by regulating EMT-related genes in renal proximal tubular cells.

Renal interstitial fibrosis (RIF) is a common pathological manifestation of chronic kidney diseases. Epithelial-mesenchymal transition (EMT) of tubular epithelial cells is considered a major cause of RIF. Although long non-coding RNAs (lncRNAs) are reportedly involved in various pathophysiological processes, the roles and underlying molecular mechanisms of lncRNAs in the progression of RIF are poorly understood. In this study, we investigated the function of lncRNAs in RIF. Microarray assays showed that expression of the lncRNA lnc-CHAF1B-3 (also called claudin 14 antisense RNA 1) was significantly upregulated in human renal proximal tubular cells by both transforming growth factor-ß1 (TGF-ß1) and hypoxic stimulation, accompanied with increased expression of EMT-related genes. Knockdown of lnc-CHAF1B-3 significantly suppressed TGF-ß1-induced upregulated expression of collagen type I alpha 1, cadherin-2, plasminogen activator inhibitor-1, snail family transcriptional repressor I (SNAI1) and SNAI2. Quantitative reverse transcriptase PCR analyses of paraffin-embedded kidney biopsy samples from IgA nephropathy patients revealed lnc-CHAF1B-3 expression was correlated positively with urinary protein levels and correlated negatively with estimated glomerular filtration rate. In situ hybridization demonstrated that lnc-CHAF1B-3 is expressed only in proximal tubules. These findings suggest lnc-CHAF1B-3 affects the progression of RIF by regulating EMT-related signaling. Thus, lnc-CHAF1B-3 is a potential target in the treatment of RIF.

Recurrent Cerebrovascular Complications under Enzyme Replacement Therapy in a Patient with Fabry Disease on Peritoneal Dialysis.

Fabry disease is an X-linked lysosomal storage disorder due to mutations in the alpha-galactosidase A gene, which leads to the accumulation of globotriaosylceramide in various organs. In Fabry disease with end-stage renal disease (ESRD), cerebrovascular events are lethal, even with enzyme replacement therapy (ERT). However, the utility of biomarkers to evaluate the ERT response is unclear. We herein report a case of recurrent cerebrovascular complications under ERT in a Fabry disease patient, progressing to ESRD on peritoneal dialysis. Further studies are warranted, but Fabry disease patients with ESRD receiving ERT might need careful long-term follow-up in cases with cerebrovascular manifestations.

Mepolizumab administration for eosinophilic granulomatosis with polyangiitis in an elderly patient with an abrupt onset of limb ischaemia and peripheral neuropathy: A case-based literature review.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a type of anti-neutrophil cytoplasmic antibody-associated vasculitis characterised by small- to medium-sized vessel vasculitis and is typically associated with eosinophilic granulomatous inflammation. EGPA can affect any organ system, most commonly the lungs, skin, and the nervous system. However, limb ulcers are rare complications and have only been described in few case reports. Furthermore, no documented cases of EGPA have been treated with mepolizumab. Herein, we report a case of an 86-year-old Japanese woman with anti-neutrophil cytoplasmic antibody-negative EGPA, who had an abrupt onset of upper limb ulcers and bilateral foot drop due to multiple mononeuropathy. Clinicopathological sural nerve biopsy showed eosinophil-associated vascular damage. The patient was administered steroids, intravenous immunoglobulin, vasodilators, and mepolizumab; this resulted in clinical improvement of her finger ulcers and peripheral neuropathy without any adverse effects. In cases of an abrupt onset of limb ischaemia and peripheral neuropathy, physicians should consider the possibility of EGPA as a differential diagnosis. Furthermore, the early administration of mepolizumab might yield better outcomes in terms of improving limb ischaemia and peripheral neuropathy.

A case of 2,8-DHA crystalline nephropathy caused by adenine phosphoribosyltransferase deficiency: diagnosis and treatment.

Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive disorder that leads to the accumulation of poorly soluble 2,8-dihydroxyadenine (DHA) in the kidneys, resulting in a variety of renal presentations including nephrolithiasis, acute kidney injury, and chronic kidney disease (CKD) caused by crystal nephropathy. Here, we report a case of a 43-year-old man with 2,8-DHA crystalline nephropathy caused by APRT deficiency strongly suspected by renal biopsy results and definitively diagnosed by a urine gas chromatography-mass spectrometry (GC/MS)-based plasma metabolomic assessment. This case represents the importance of awareness and recognition of the signs and symptoms of this rare condition and its progression to CKD, which can be prevented by the early administration of xanthine oxidoreductase inhibitors.

Interleukin-6 blockade reduces salt-induced cardiac inflammation and fibrosis in subtotal nephrectomized mice.

Cardiovascular disease is the most common comorbidity in patients with chronic kidney disease (CKD), affecting both their prognosis and quality of life. Cardiac fibrosis is common in patients with CKD with left ventricular diastolic dysfunction, and it is associated with increased risk of heart failure and mortality. Recent evidence suggests that high salt intake activates immune responses associated with local accumulation of sodium. We reported that high salt intake promotes cardiac inflammation in subtotal nephrectomized (Nx) mice. We investigated the effects of administration of MR16-1, a rat anti-mouse monoclonal interleukin (IL)-6 receptor antibody, in Nx mice with salt loading (Nx-salt). Expression of monocyte chemoattractant protein-1, tumor necrosis factor-α, IL-1ß, and IL-6 mRNAs and macrophage infiltration was significantly reduced in the heart of Nx-salt mice treated with MR16-1 (Nx-salt-MR16-1) compared with Nx-salt mice treated with control rat rat IgG1 (Nx-salt-rat IgG1). Correspondingly, cardiac fibrosis was significantly attenuated in Nx-salt-MR16-1 mice compared with Nx-salt-rat IgG1 mice. Furthermore, in the heart of Nx-salt-MR16-1 mice, expression of mRNA for nicotinamide adenine dinucleotide phosphate oxidase-2, an oxidative stress marker, was significantly downregulated compared with Nx-salt-rat IgG1 mice. Increases in cardiac metabolites, including histidine and γ-butyrobetaine, were also reversed by IL-6 blockade treatment. In conclusion, IL-6 blockade exerts anti-inflammatory, antifibrotic, and partial antioxidative effects in the heart of Nx-salt mice.NEW & NOTEWORTHY In the present study, IL-6 blockade exerted anti-inflammatory, antifibrotic, and partial antioxidative effects on the hearts of mice with CKD on a high-salt diet. Therefore, IL-6 potentially mediates cardiac fibrosis induced by high salt intake in patients with CKD, a finding with therapeutic implications. Of note, the next therapeutic implication may simply be the reinforcement of low-salt diets or diuretics and further research on the anti-inflammatory effects of these measures rather than IL-6 blockade with high-salt diet.

Association of alcohol consumption with the incidence of proteinuria and chronic kidney disease: a retrospective cohort study in Japan.

BACKGROUND: The difference in the clinical impact of alcohol consumption on kidney function based on sex remains to be elucidated. This study aimed to assess the association between the dose of alcohol consumption and the incidence of proteinuria and chronic kidney disease stratified by sex. METHODS: This retrospective cohort study included 26,788 workers (19,702 men and 7086 women) with normal renal function (estimated glomerular filtration rate ≥ 60 mL/min/1.73 m2) at annual health examinations between January 2010 and March 2015 in Japan. The main exposure was alcohol consumption. The primary outcomes were the incidence of proteinuria (dipstick urinary protein ≥ 1) and incidence of low estimated glomerular filtration rate (eGFR; rate < 60 mL/min per 1.73 m2; decreased from the baseline eGFR by 25%). RESULTS: During a median observational period of 4 years (interquartile range: 2-6), 1993 (10.1%) men and 462 (6.5%) women developed proteinuria, whereas 667 (3.4%) men and 255 (3.6%) women developed low eGFR. After adjustment for clinically relevant factors using a Cox proportional hazards model, alcohol consumption of ≥ 46 g/day in females was significantly associated with the incidence of proteinuria (hazard ratio, 1.57; 95% confidence interval, 1.10-2.26) and low eGFR (hazard ratio, 1.62; 95% confidence interval, 1.04-2.53). However, no significant association between alcohol consumption and primary outcomes was observed in men. CONCLUSIONS: In conclusion, daily higher alcohol consumption was significantly associated with a higher incidence of proteinuria and low eGFR among women. Women might be prone to high alcohol consumption with kidney dysfunction.

Anti-neutrophil cytoplasmic antibody-associated vasculitis complicated by thrombotic microangiopathy with posterior reversible encephalopathy syndrome successfully treated with eculizumab: A case report.

Thrombotic microangiopathy is characterised by endothelial cell injury, intravascular platelet-fibrin thrombi, and vascular damage, leading to acute kidney injury, thrombocytopenia, and microangiopathic haemolytic anaemia. Among the autoimmune diseases related to thrombotic microangiopathy, anti-neutrophil cytoplasmic antibody-associated vasculitis-related thrombotic microangiopathy cases have been rarely reported; therefore, the optimal treatment for associated vasculitis-related thrombotic microangiopathy remains unknown. An 84-year-old woman without significant medical history presented with a 1-month history of general fatigue, fever, and deteriorating bilateral leg numbness and was admitted to our hospital. She had elevated myeloperoxidase anti-neutrophil cytoplasmic antibody levels, polyneuropathy, and rapid progressive glomerulonephritis because of pauci-immune crescentic glomerulonephritis, as revealed by a kidney biopsy. Accordingly, we diagnosed her with microscopic polyangiitis. After administering methylprednisolone pulse therapy, rituximab, and intravenous immunoglobulin, the patient's mental state deteriorated, presenting signs of thrombotic microangiopathy with posterior reversible encephalopathy syndrome. Intermittent haemodialysis and plasma exchange were initiated; however, her condition did not improve, and eculizumab administration was initiated thereafter. The patient's symptoms showed a remarkable response to eculizumab; thrombotic microangiopathy findings, kidney function, and neurological symptoms improved after only two doses of eculizumab, and she achieved sustained remission. The extremely effective course of eculizumab treatment indicated that overt complement activation affected the development of thrombotic microangiopathy. Anti-neutrophil cytoplasmic antibody-associated vasculitis-related thrombotic microangiopathy may be mediated by complement activation, and prompt induction of eculizumab therapy may be a superior strategy to prevent organ damage. Further studies should elucidate the role of complement activation in associated vasculitis-related thrombotic microangiopathy and the efficacy of eculizumab treatment.

Relationships between Slc1a5 and Osteoclastogenesis.

Slc1a5 (ASCT2) encodes a small neutral amino-acid exchanger and is the most well-studied glutamine transporter in cancer cells. To investigate the role of Slc1a5 in osteoclastogenesis, we developed Slc1a5-deficient mice by using a conventional gene-targeting approach. The Slc1a5-/- mice showed no obvious abnormalities in growth. Glutamine uptake was assessed in Slc1a5+/+ and Slc1a5-/- bone marrow cells stimulated with RANKL. The rate of glutamine uptake in Slc1a5-/- bone marrow cells was reduced to 70% of that of cells from Slc1a5+/+ bone marrow. To confirm the involvement of Slc1a5 in osteoclast formation, bone marrow cells derived from Slc1a5+/+ or Slc1a5-/- mice were stimulated with RANKL and macrophage colony-stimulating factor and stained with tartrate-resistant acid phosphatase. The bone resorption activity and actin ring formation of stimulated cells were measured. The formation of multinucleated osteoclasts in bone marrow cells isolated from Slc1a5-/- mice was severely impaired compared with those from Slc1a5+/+ mice. RANKL-induced expression of ERK, NFκB, p70S6K, and NFATc1 was suppressed in Slc1a5-/- osteoclasts. These results show that Slc1a5 plays an important role in osteoclast formation.

Low-GDP, pH-neutral solutions preserve peritoneal endothelial glycocalyx during long-term peritoneal dialysis.

BACKGROUND: During peritoneal dialysis (PD), solute transport and ultrafiltration are mainly achieved by the peritoneal blood vasculature. Glycocalyx lies on the surface of endothelial cells and plays a role in vascular permeability. Low-glucose degradation product (GDP), pH-neutral PD solutions reportedly offer higher biocompatibility and lead to less peritoneal injury. However, the effects on the vasculature have not been clarified. METHODS: Peritoneal tissues from 11 patients treated with conventional acidic solutions (acidic group) and 11 patients treated with low-GDP, pH-neutral solutions (neutral group) were examined. Control tissues were acquired from 5 healthy donors of kidney transplants (control group). CD31 and ratio of luminal diameter to vessel diameter (L/V ratio) were evaluated to identify endothelial cells and vasculopathy, respectively. Immunostaining for heparan sulfate (HS) domains and Ulex europaeus agglutinin-1 (UEA-1) binding was performed to assess sulfated glycosaminoglycans and the fucose-containing sugar chain of glycocalyx. RESULTS: Compared with the acidic group, the neutral group showed higher CD31 positivity. L/V ratio was significantly higher in the neutral group, suggesting less progression of vasculopathy. Both HS expression and UEA-1 binding were higher in the neutral group, whereas HS expression was markedly more preserved than UEA-1 binding in the acidic group. In vessels with low L/V ratio, which were found only in the acidic group, HS expression and UEA-1 binding were diminished, suggesting a loss of glycocalyx. CONCLUSION: Peritoneal endothelial glycocalyx was more preserved in patients treated with low-GDP, pH-neutral solution. The use of low-GDP, pH-neutral solutions could help to protect peritoneal vascular structures and functions.

C1 inhibitor mitigates peritoneal injury in zymosan-induced peritonitis.

Peritonitis, due to a fungal or bacterial infection, leads to injury of the peritoneal lining and thereby forms a hazard for the long-term success of peritoneal dialysis (PD) and remains a lethal complication in patients with PD. This study investigated whether C1 inhibitor (C1-INH) could protect against the progression of peritoneal injuries with five daily administrations of zymosan after mechanical scraping of the rat peritoneum to mimic fungal peritonitis. Severe peritoneal injuries were seen in this model, accompanied by fibrinogen/fibrin exudation and peritoneal deposition of complement activation products such as activated C3 and C5b-9. However, intraperitoneal injection of C1-INH decreased peritoneal depositions of activated C3 and C5b-9, ameliorated peritoneal thickening, reduced the influx of inflammatory cells, and prevented the production of peritoneal fibrous layers with both one and two doses of C1-INH each day. Our results suggest that C1-INH might be useful to protect against peritoneal injuries after causes of peritonitis such as fungal infection. This clinically available agent may thus help extend the duration of PD.NEW & NOTEWORTHY Peritoneal injuries associated with peritonitis comprise an important issue to prevent long-term peritoneal dialysis (PD) therapy. Here, we showed that C1 inhibitor (C1-INH), as an anticomplement agent, protected against peritoneal injuries in a peritonitis animal model related to fungal infection. Therefore, C1-INH might be useful to protect against peritoneal injuries after peritonitis due to fungal infection. This clinically available agent may thus help extend the duration of PD.