Effectiveness of neutralizing antibody cocktail in hemodialysis patients: a case series of 20 patients treated with or without REGN-COV2.

The number of patients with SARS-CoV-2 infection continues to increase, and it has become a global pandemic. Although there is an urgent need to establish an effective treatment, the medication available for dialysis patients has been limited. An antibody cocktail containing two SARS-CoV-2-neutrarizing antibodies, REGN-COV2 has been granted special approval for COVID-19 in Japan, since July 2021, and this intravenous preparation can be used for dialysis patients. At our hospital, we had 22 hemodialysis patients with COVID-19, and five of them were treated with REGN-COV2. On admission, four of the five patients had moderate disease (pneumonia but O2 inhalation) and one patient had mild disease (not having pneumonia). The mean duration of hospitalization treated with REGN-COV2 was 10.2 ± 2.86 days (mean ± SD), which was less than half, compared to patients untreated of similar severity on admission (22.12 ± 15.5). The time to fever resolution was average 7 days, and no cases progressed to severe illness or death. Among these patients, no obvious adverse reactions were shown. Although more studies with a larger number of patients could be needed for a rigorous evaluation of the effect, our result suggests that REGN-COV2 may be safe and having the possibilities in preventing severe disease in hemodialysis patients. Given the difficulty in securing inpatient beds tend to be in short supply, the strategy combined with neutralizing antibody could be beneficial for end-stage kidney disease (ESKD) patients with hemodialysis who are at high risk of severe disease.

Munc18-1-interacting protein 3 mitigates renal fibrosis through protection of tubular epithelial cells from apoptosis.

BACKGROUND: Tubulointerstitial fibrosis is a hallmark of chronic kidney disease (CKD), and is initiated by tubular epithelial cell (TEC) injury. Hypoxia promotes tubular cell death, fibrosis and CKD progression. Munc18-1-interacting protein 3 (Mint3) is a molecule that activates hypoxia-inducible factors (HIFs) by binding and suppressing factor inhibiting HIF-1 (FIH). However, the role of Mint3 in tubulointerstitial fibrosis remains unknown. METHODS: We induced fibrosis of the kidney after unilateral ischemia-reperfusion injury (uIRI) in Mint3-knockout and littermate wild-type mice. The duration of ischemia was 23 min and the kidneys were harvested at 24 h and 7 days after ischemia-reperfusion. The function of Mint3 was further investigated by using mouse cortical tubular (MCT) cells, which were treated with Mint3 and/or FIH small interfering RNA and exposed to normoxia or hypoxia. RESULTS: Knockout of Mint3 did not affect the acute injury induced by uIRI, but exacerbated the tubulointerstitial fibrosis, accompanied by an increase in TEC apoptosis. Consistently, hypoxia-induced apoptosis of MCT cells was aggravated by Mint3 knockdown. Unexpectedly, the additional knockdown of FIH did not suppress the increase in apoptosis by Mint3 knockdown, demonstrating the irrelevance of the FIH/HIF pathway. Therefore, we next focused on nuclear factor (NF)-κB, which has an anti-apoptotic role. Indeed, not only the expression of the inhibitory NF-κB p50 but also the DNA-binding activity of p50/p50 homodimer was increased by knockdown of Mint3 in the TECs, along with the decreased expressions of the NF-κB-targeted anti-apoptotic genes. An increase in NF-κB p50 was also confirmed in Mint3-knockout kidneys. CONCLUSIONS: Mint3 in epithelial cells protects the cells from apoptosis by up-regulating anti-apoptotic effects of NF-κB, leading to fibrosis suppression. This new pathophysiology of tubulointerstitial fibrosis could be a target of future therapy for CKD.

Nephrotic syndrome due to minimal-change disease superimposed on anti-glomerular basement membrane antibody positive glomerulonephritis; a case report.

BACKGROUND: The prognosis for renal function in anti-GBM glomerulonephritis (anti-GBM GN) is extremely poor, and when renal impairment progresses severely, it is difficult to expect improvement. In addition, it is also known that once the disease activity can be controlled by aggressive treatment, its recurrence is rare. We experienced an anti-GBM GN that improved from severe renal dysfunction and relapsed. A possible cause was the superimpose of nephrotic syndrome due to minimal change disease (MCD). CASE PRESENTATION: A 30-year-old man was admitted to our hospital because of general malaise, fever, oliguria and renal dysfunction. The patient's laboratory data showed serum creatinine as high as 6.6 mg/dl, and severe inflammation (C-reactive protein 20.6 mg/dl). Anti-glomerular basement membrane antibody (anti-GBM Ab) was detected in his serum, which led to the diagnosis of anti-GBM GN. Treatment was initiated with high-dose glucocorticoid (GC) and plasma exchange therapy (PE), and the patient's renal function and oliguria improved rapidly and he was discharged 40 days after admission. Renal biopsy findings showed cellular crescents associated with linear IgG depositions along the glomerular tufts compatible with anti-GBM GN, but only about one-third of the glomeruli was involved, suggesting that it still remains an early stage of the disease. However, 2 months after discharge, he had a relapse and was readmitted due to severe proteinuria with positive anti-GBM Ab. On the second admission, after high-dose GC and PE combined with intravenous cyclophosphamide, and remission was achieved. Despite the relatively minor renal biopsy findings, the patient showed rapid renal dysfunction and relatively rapid improvement with our treatment. Electron microscopy of the renal biopsy tissue showed significant foot process effacement on podocytes in the apparently normal glomeruli, without electron dense deposits. CONCLUSION: On the basis of clinical course and renal pathology, it is suggested that the present case was a rare complication of an early stage of anti-GBM GN and minimal change nephrotic syndrome. Although the simultaneous development of anti-GBM GN and MCD with anti-GBM antibody is unclear, it might have been precipitated by influenza infection or some unknown factor.

Vascular adhesion protein-1 enhances neutrophil infiltration by generation of hydrogen peroxide in renal ischemia/reperfusion injury.

Vascular adhesion protein-1 (VAP-1) is a unique molecule since it acts as an adhesion molecule as well as an ectoenzyme catalyzing oxidative deamination of primary amines and generates hydrogen peroxide in the extracellular space. While VAP-1 is implicated in various inflammatory diseases, its role in acute kidney injury is less characterized. Here we studied VAP-1 expression in the kidney and the effect of its inhibition in a rat model of renal ischemia/reperfusion injury. VAP-1 was predominantly expressed in pericytes, which released enzymatically active enzyme. In vivo, a specific VAP-1 inhibitor, RTU-1096, significantly ameliorated rat renal ischemia/reperfusion injury and decreased neutrophil infiltration measured 12 hours after injury without altering macrophage or T lymphocyte populations. The protective effect of VAP-1 inhibition was lost in neutrophil-depleted rats, suggesting its inhibition ameliorated renal ischemia/reperfusion injury by suppressing neutrophil infiltration. To investigate whether hydrogen peroxide generated by VAP-1 enzyme reaction enhances neutrophil infiltration, we conducted an under-agarose migration assay with purified human neutrophils. Recombinant human VAP-1 significantly induced neutrophil migration, which was almost completely inhibited by RTU-1096 or catalase. Thus, VAP-1 plays a critical role in the pathophysiology of renal ischemia/reperfusion injury by enhancement of neutrophil infiltration generating a local hydrogen peroxide gradient. Hence, VAP-1 inhibition may be a novel therapy in ischemic acute kidney injury.

Deficient Autophagy Results in Mitochondrial Dysfunction and FSGS.

FSGS is a heterogeneous fibrosing disease of the kidney, the cause of which remains poorly understood. In most cases, there is no effective treatment to halt or retard progression to renal failure. Increasing evidence points to mitochondrial dysfunction and the generation of reactive oxygen species in the pathogenesis of CKD. Autophagy, a major intracellular lysosomal degradation system, performs homeostatic functions linked to metabolism and organelle turnover. We prevented normal autophagic pathways in nephrons of mice by mutating critical autophagy genes ATG5 or ATG7 during nephrogenesis. Mutant mice developed mild podocyte and tubular dysfunction within 2 months, profound glomerular and tubular changes bearing close similarity to human disease by 4 months, and organ failure by 6 months. Ultrastructurally, podocytes and tubular cells showed vacuolization, abnormal mitochondria, and evidence of endoplasmic reticulum stress, features that precede the appearance of histologic or clinical disease. Similar changes were observed in human idiopathic FSGS kidney biopsy specimens. Biochemical analysis of podocytes and tubules of 2-month-old mutant mice revealed elevated production of reactive oxygen species, activation of endoplasmic reticulum stress pathways, phosphorylation of p38, and mitochondrial dysfunction. Furthermore, cultured proximal tubule cells isolated from mutant mice showed marked mitochondrial dysfunction and elevated mitochondrial reactive oxygen species generation that was suppressed by a mitochondrial superoxide scavenger. We conclude that mitochondrial dysfunction and endoplasmic reticulum stress due to impaired autophagic organelle turnover in podocytes and tubular epithelium are sufficient to cause many of the manifestations of FSGS in mice.

Resident renal mononuclear phagocytes comprise five discrete populations with distinct phenotypes and functions.

Recent reports have highlighted greater complexity, plasticity, and functional diversity of mononuclear phagocytes (MPCs), including monocytes, macrophages, and dendritic cells (DCs), in our organs than previously understood. The functions and origins of MPCs resident within healthy organs, especially in the kidney, are less well understood, whereas studies suggest they play roles in disease states distinct from recruited monocytes. We developed an unbiased approach using flow cytometry to analyze MPCs residing in the normal mouse kidney, and identified five discrete subpopulations according to CD11b/CD11c expression as well as F4/80, CD103, CD14, CD16, and CD64 expression. In addition to distinct marker profiles, these subpopulations have different lineages and expression of genes involved in tissue homeostasis, including angiogenesis. Among them, the CD11b(int)CD11c(int) F4/80(high) subpopulation notably exhibited high capacity to produce a representative anti-inflammatory cytokine, IL-10. Each subpopulation had different degrees of both macrophage (phagocytosis) and DC (Ag presentation) capacities, with a tendency to promote differentiation of regulatory T cells, whereas two of these showed expression of transcription factors reported to be highly expressed by classical DCs, and proclivity to exit the kidney following stimulation with LPS. In summary, resident kidney MPCs comprise discrete subpopulations, which cannot be simply classified into the conventional entities, and they produce anti-inflammatory and tissue-homeostatic factors to differing degrees.

Wnt signalling in kidney diseases: dual roles in renal injury and repair.

Wnt signalling is a complex, highly conserved, cell-to-cell communication pathway in multicellular organisms, regulating cell fate, function and phenotype in development, and diseases, including neoplasia. Although the critical role of the Wnt pathway in nephrogenesis is well established, recent investigations have shown its involvement in many adult kidney diseases, including ischaemic kidney injury, glomerular diseases, diabetic nephropathy, interstitial fibrosis and cystic kidney diseases. Overall, activation of the Wnt pathway is deleterious to many chronic diseases of the kidney, contributing to the maintenance of cells in an activated state. In addition, the Wnt pathway is activated during repair and regeneration in animal models of acute ischaemic injury, a scenario that is frequently encountered in human acute kidney injury. This activation recapitulates features of nephrogenesis and appears to play an indispensable role in repair and regeneration in this acute setting. As tools are being developed to regulate the Wnt pathway intracellularly and at the cell surface, the Wnt pathway has become a potential avenue for urgently required novel therapeutics for treating human kidney diseases. In this review, we describe consensus models for major Wnt signalling cascades and then discuss their roles in kidney diseases.

Plasmapheresis for systemic vasculitis.

Systemic vasculitides include a variety of, and numerous diseases. In 2012, the International CHAPEL HILL Consensus Conference (CHCC2012) led to a major reorganization of the classification of vasculitis, and this is still in wide use today. Although the results of plasmapheresis for individual diseases have been sometimes shown, there are few systematic reviews that discuss the effects along with vasculitis classification. Therefore, we will discuss the efficacy and the latest evidence for each vasculitis according to the CHCC 2012 classification in this review. This review provides a comprehensive overview of the estimation of plasmapheresis in each of the vasculitides, with a particular focus on small vasculitides, which have recently discussed frequently. For some time now, plasma exchange therapy (PEX) has been frequently used and is expected to be effective in some diseases, most of which are included in small vessel vasculitides. In particular, data showing efficacy have been accumulated for immune complex vasculitis, and the recommendation seems to be high. For instance, anti-GBM nephritis, concomitant use of PEX is essential and strongly recommended. On the other hand, for ANCA-related vasculitis among small vessel vasculitis, RCTs have recently shown negative results. In particular, the PEXIVAS trial statistically showed that PEX has no potential to reduce the mortality and renal death in AAV, but the ASFA, ACR, and KDIGO guidelines following this trial all regard PEX as salvage therapy or selective treatment for severe cases. As plasmapheresis is often performed in combination with other therapies, it is difficult to evaluate to clarify its efficacy on its own, and this predisposition may be pronounced in vasculitis, a rare disease. Although statistically significant differences are not apparent, the diseases that show a trend toward efficacy may possibly include treatment-sensitive subgroups. Further analysis is expected in the future.

Clinical features of psoriatic arthritis.

Psoriatic arthritis (PsA) is associated with decreased quality of life. As delayed diagnosis may lead to progressive joint destruction and long-term disability, the key clinical features of PsA should be recognizable to a wide range of clinicians to facilitate early diagnosis. In addition to assessment and identification of skin and nail lesions, which occur in up to 85% of those with musculoskeletal manifestations, clinicians should be aware of both the peripheral and axial manifestations of musculoskeletal disease reviewed here. Peripheral joint diseases include polyarticular, oligoarticular, distal, and arthritis mutilans subtypes, and cognizance of these patterns of disease, as well as periarticular manifestations, including dactylitis and enthesitis, is useful for swift diagnosis of PsA. Axial psoriatic arthritis (axial PsA), also known as the spondylitis subtype, may be limited to the spine and sacroiliac joints, but may also affect peripheral structures. Meticulous history-taking and physical examination and familiarity with appropriate imaging studies are often necessary to distinguish axial-PsA from other differential diagnoses. Swift diagnosis and treatment are necessary to both control PsA disease and mitigate the risks of the many associate comorbidities that may accompany it.

Extensive bilateral renal metastases of non-small cell lung carcinoma caused acute kidney injury resulting in end-stage renal disease.

Non-small cell lung carcinoma unusually causes clinically relevant metastases in the kidney while they are usually found only in autopsy. Acute kidney injury (AKI) due to direct metastatic invasion of a solid tumor is also very rare whereas it usually happens with hematologic malignancy, including lymphoma. We report a case with these two rarities. A 54-year-old man who had a 6.7 × 6.0 cm-sized tumor in the left upper lobe of the lung in computed tomography was diagnosed as squamous cell lung carcinoma with bronchoscopy with biopsy. His renal function was normal and no proteinuria or hematuria was recognized. He underwent left upper lobectomy and the pathologic examination revealed pT4N1M0 stage IIIA disease. Four months after the surgery, a single brain metastasis in the right frontal lobe found in brain magnetic resonance imaging was treated with Gamma Knife radiosurgery. He presented with macroscopic hematuria and AKI (the serum creatinine level was 1.35 mg/dL) nine months after surgery. The cause was enormous bilateral renal metastases, maximally 8 cm-sized lesions with poor enhancement, which were found in enlarged bilateral kidneys in enhanced CT. Intrapulmonary metastatic lesions were also newly detected. Chemotherapy with pembrolizumab, an antibody against anti-programmed cell death protein 1, had little effect and his renal function continued to decline rapidly, resulting in end-stage renal disease and maintenance hemodialysis. Chemotherapy with carboplatin and paclitaxel was additionally performed. However, two months after hemodialysis induction, the patient died with pneumonia and acute respiratory distress syndrome.

Indoxyl sulfate inhibits proliferation of human proximal tubular cells via endoplasmic reticulum stress.

Uremic toxins can deteriorate renal function, but little is known about its mechanism. Because tubular injury is central to progression of chronic kidney disease (CKD), we investigated the effects of a representative uremic toxin indoxyl sulfate (IS) on tubular cells. IS induced endoplasmic reticulum (ER) stress in cultured human proximal tubular cells, demonstrated by the increase in C/EBP homologous protein (CHOP) in the immunoblots. Moreover, administration of an oral adsorbent AST-120 reduced serum IS concentration and decreased tubular expression of CHOP in immunohistochemistry in 5/6-nephretomized, CKD model, rats. Furthermore, we disclosed that IS inhibited proliferation of tubular cells in 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium and 5-bromo-2'-deoxyuridine assay, whereas the results of trypan blue exclusion and lactate dehydrogenase assay showed that IS did not promote cell death. This inhibition was mitigated by small interfering (si) RNA against CHOP. Furthermore, IS increased the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) (p21). Surprisingly, this was mediated by the inflammatory cytokine interleukin (IL)-6, the expression of which was decreased by siRNA against activating transcription factor 4, another ER stress marker; however, the induction of IL-6 and p21 by IS was not suppressed by siRNA targeted to CHOP, suggesting that they were downstream of ER stress, but independent of CHOP. Moreover, we found that their upregulation was dependent on ERK, using the ERK pathway inhibitor U-0126. Collectively, we demonstrated that IS induced ER stress in tubular cells and inhibited cell proliferation via two pathways downstream of ER stress, namely CHOP and ERK-IL-6-p21. These are possible targets for suppressing progression of CKD.

Uremia induces abnormal oxygen consumption in tubules and aggravates chronic hypoxia of the kidney via oxidative stress.

In addition to causing uremic symptoms, uremic toxins accelerate the progression of renal failure. To elucidate the pathophysiology of uremic states, we investigated the effect of indoxyl sulfate (IS), a representative uremic toxin, on oxygen metabolism in tubular cells. We demonstrated an increase in oxygen consumption by IS in freshly isolated rat and human proximal tubules. Studies utilizing ouabain, the Na-K-ATPase inhibitor, and apocynin, the NADPH oxidase inhibitor, as well as the in vivo gene-silencing approach to knock down p22(phox) showed that the increase in tubular oxygen consumption by IS is dependent on Na-K-ATPase and oxidative stress. We investigated whether the enhanced oxygen consumption led to subsequent hypoxia of the kidney. An increase in serum IS concentrations in rats administered indole was associated with a decrease in renal oxygenation (8 h). The remnant kidney in rats developed hypoxia at 16 wk. Treatment of the rats with AST-120, an oral adsorbent that removes uremic toxins, reduced serum IS levels and improved oxygenation of the kidney. Amelioration of hypoxia in the remnant kidney was associated with better renal functions and less histological injury. Reduction of serum IS levels also led to a decrease in oxidative stress in the kidney. Our ex vivo and in vivo studies implicated that uremic states may deteriorate renal dysfunction via dysregulating oxygen metabolism in tubular cells. The abnormal oxygen metabolism in tubular cells by uremic toxins was, at least in part, mediated by oxidative stress.

Endoplasmic reticulum stress induces autophagy in renal proximal tubular cells.

BACKGROUND: Autophagy, an intracellular self-degradation system conserved throughout eukaryotes, plays an important role in a variety of biological processes, including cell death, development, cancer, defence against infection and neurodegeneration. However, little information about autophagy in renal tubular cells is available. We investigated the relationship of autophagy with endoplasmic reticulum (ER) stress in proximal tubular cells. METHODS: Immortalized rat proximal tubular cells were exposed to the classic ER stress inducers tunicamycin or brefeldin A. Autophagy was detected mainly by immunoblot analysis of LC3, a widely used marker of autophagy, and also by immunofluorescent cytochemistry of LC3 and electron microscopy. Biological significance of the phenomenon was studied using bafilomycin A1, an inhibitor of autophagosome degradation. Signal transduction pathways following ER stress were also investigated using inhibitors of the MAPK pathway. RESULTS: Both ER stress inducers significantly increased LC3-II as a marker of autophagy in immunoblot analysis. Immunocytochemistry of LC3 and electron microscopy also showed activation of autophagy by ER stress. Inhibition by bafilomycin A1 showed that autophagy following ER stress fulfilled its intrinsic function, namely degradation of cytoplasmic components. Further, use of the MEK 1/2 inhibitor U0126, which inhibits ER stress-induced autophagy induction and ERK activation, showed that ERK, a MAPK family member, was necessary to the induction of autophagy. CONCLUSIONS: For the first time, we demonstrate the induction of autophagy following ER stress in renal tubules, and clarify its mechanism. These findings serve as the foundation for further investigation into autophagy in renal diseases.

Myeloperoxidase antineutrophil cytoplasmic antibody-associated vasculitis with diffuse tubulointerstitial nephritis.

Renal involvement in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is characterized by focal segmental crescentic and/or necrotizing glomerulonephritis. Here, we report the case of a 66-year-old woman showing myeloperoxidase (MPO)-ANCA positivity and mononeuritis multiplex whose kidney biopsy revealed severe and diffuse tubulointerstitial nephritis despite the fact that crescentic necrotizing glomerulonephritis was focal. The mechanism of tubulointerstitial injury in ANCA-associated vasculitis remains unclear. Further studies are necessary to confirm the relationship between diffuse tubulointerstitial nephritis and ANCA-associated vasculitis.

Preconditioning with endoplasmic reticulum stress ameliorates mesangioproliferative glomerulonephritis.

Accumulating evidence suggests a pathophysiologic role of endoplasmic reticulum (ER) stress in kidney disease. This study investigated the potential of therapeutic approaches targeting ER stress in the anti-Thy1 model of mesangioproliferative glomerulonephritis in rats. Immunohistochemistry and Western blotting showed a time-dependent increase in the expression of the ER stress-inducible chaperones glucose-regulated protein 78 (GRP78) and oxygen-related protein 150 in isolated glomeruli, especially in the glomerular epithelial cells and mesangial cells, after induction of anti-Thy1 nephritis. For evaluation of whether preconditioning with ER stress ameliorates the severity of disease, rats were pretreated with a subnephritogenic dose of the ER stress inducer tunicamycin or thapsigargin for 4 d before disease was induced. Although preconditioning with ER stress had no effect on the degree of disease induction, it strongly ameliorated the manifestations of disease, evidenced by marked reductions in microaneurysm formation, mesangial proliferation, and adhesion of Bowman's capsule to the glomerular tuft. This improvement in histologic damage was associated with reduced proteinuria (39.4 +/- 10.5 versus 126.1 +/- 18.1 mg/d; P < 0.01) and with attenuated increases in glucose-regulated protein 78 and oxygen-related protein 150 expression. Of note, pretreatment with tunicamycin or thapsigargin decreased the excessive ER stress-induced intracellular signaling observed in anti-Thy1 nephritis. In conclusion, preconditioning with ER stress ameliorates the severity of disease in rats with anti-Thy1 nephritis. These findings suggest the possibility of therapeutic approaches targeting ER stress in mesangioproliferative glomerulonephritis.

D-serine, a novel uremic toxin, induces senescence in human renal tubular cells via GCN2 activation.

The prevalence of chronic kidney disease (CKD), characterized by progressive renal dysfunction with tubulointerstitial fibrosis, is increasing because of societal aging. Uremic toxins, accumulated during renal dysfunction, cause kidney damage, leading to renal deterioration. A recent metabolomic analysis revealed that plasma D-serine accumulation is associated with faster progression of renal dysfunction in CKD patients. However, the causal relationship and the underlying mechanisms remain unclear. Herein, we demonstrated that D-serine markedly induced cellular senescence and apoptosis in a human proximal tubular cell line, HK-2, and primary culture of human renal tubular cells. The former was accompanied by G2/M cell cycle arrest and senescence-associated secretory phenotype, including pro-fibrotic and pro-inflammatory factors, contributing to tubulointerstitial fibrosis. Integrated stress response mediated by the general control nonderepressible 2 played an important role in D-serine-induced tubular cell toxicity and pro-fibrotic phenotypes, accelerating CKD progression and kidney aging. D-serine upregulated the L-serine synthesis pathway. Furthermore, D-serine-induced suppression of tubular cell proliferation was ameliorated by L-serine administration, indicating that D-serine exposure induced an L-serine-deprived state in tubular cells, compensated by L-serine synthesis. Thus, this study unveils molecular mechanisms underlying D-serine-induced tubular damage and pro-fibrotic phenotypes, suggesting that D-serine is a uremic toxin involved in CKD pathogenesis.

Umbilical Cord Blood Transplantation-associated Nephrotic Syndrome Successfully Treated by Low-density Lipoprotein Apheresis.

The development of nephrotic syndrome (NS) after umbilical cord transplantation (UBT) has been reported in only four cases to date. We herein report the case of a 50-year-old woman who developed NS 94 days after UBT. She fell into oliguria and required dialysis. A kidney biopsy revealed focal and segmental glomerulosclerosis. Although glucocorticoid monotherapy did not improve her condition, the addition of low-density lipoprotein (LDL) apheresis resulted in remission of NS, a drastic improvement in her renal function, and withdrawal from dialysis. To the best of our knowledge, this is the first report of UBT-associated NS treated with LDL apheresis.

Hypoxia and fibrosis in chronic kidney disease: crossing at pericytes.

Chronic kidney disease (CKD) is placing an increasing burden on patients and societies because no decisive therapy has been established. Tubulointerstitial lesions accompanied by fibrosis, inflammatory cells, and capillary rarefaction not only characterize, but also aggravate renal dysfunction in CKD. In this setting, renal cells, particularly tubular cells, suffer from hypoxia caused by the imbalance of blood perfusion and oxygen demand despite their adaptive responses represented by upregulation of hypoxia-inducible factors (HIFs). Fibrosis is a pathological state characterized by excess extracellular matrix (ECM) deposition, which is also a hallmark and causative factor of many chronic diseases including CKD. Recent studies have suggested that the dominant origin of ECM-producing myofibroblasts (MFs) may be pericytes, which are indispensable cells for maintaining proper capillary functions, as they wrap capillaries and stabilize them through a fine-tuned interplay with endothelial cells. During fibrosis, pericytes are activated and detach from capillaries before conversion into MFs, which compromises capillaries and worsens hypoxia. We also discuss how hypoxia and HIFs affect fibrogenesis. Given that hypoxia is caused by insufficient angiogenesis and that fibrosis results from pericyte loss, restoration of pericytes should be an intriguing target for overcoming both hypoxia and fibrosis. We propose the deactivation of MFs to recover lost pericytes as a promising therapy for CKD.

Changes in macrophage phenotype as the immune response evolves.

Mononuclear phagocytic cells (MPCs), including macrophages and dendritic cells (DCs), are widely distributed throughout our organs where they perform important homeostatic, surveillance and regenerative tasks. In response to infection or injury, the composition and number of MPCs change remarkably, in part due to the recruitment of inflammatory monocytes from bone marrow. In infection or injury, macrophages and DCs perform important innate and adaptive immune roles from the initial insult through repair and regeneration of the tissue and resolution of inflammation. Evidence from mouse models of disease has shown increasing complexity and subtlety to the mononuclear phagocytic system, which will be reviewed here. New studies show that in addition to monocytes, the resident populations of mononuclear phagocytes expand in disease states and play distinct but important roles in the immune response. Finally, new insights into these functionally diverse cells are now translating into therapeutics to treat human disease.