Refractory lupus nephritis: a survey.

'Refractory lupus nephritis' is a frequently used term but poorly defined. We conducted a survey among nephrologists and rheumatologists to spot the diversity of perceptions of this term and to better understand the clinical practice related to 'refractory lupus nephritis'. A total of 145 questionnaires completed by lupus nephritis experts were available for analysis, of which 52% were nephrologists, 34% rheumatologists, and 13% internists. Response to induction treatment was mostly assessed after six months (58%), but assessment at three months was more common with the use of the EURO lupus protocol than with other treatment protocols. Rheumatologists used urinary sediment to assess response more frequently than nephrologists (66 vs. 48%, p < 0.05, Chi2), while nephrologists conversely relied significantly more on clinical symptoms (61 vs. 31%, p < 0.0001, Chi2). Non-nephrologists quantified proteinuria preferentially by 24 h urine sampling, while the majority of nephrologists relied on the urinary protein/creatinine ratio (UPCR) or the albumin/creatinine ratio of spot urine samples (59 vs. 38%, p < 0.05, Chi2). A total of 91% were concerned about persistent immunological systemic lupus erythematosus activity. There was less concern about drug adherence, renal scarring, genetic factors or other kidney diseases. Less than 20% check for drug adherence by regularly monitoring drug plasma levels. Nephrologists considered a re-biopsy more often than rheumatologists (58 vs. 38%, p < 0.05, Chi2). Together, among lupus nephritis experts there is considerable diversity in the perception of what the term 'refractory lupus nephritis' describes and how it is defined. A consensus definition of 'refractory lupus nephritis' is needed.

Cellular and Molecular Mechanisms of Autoimmunity and Lupus Nephritis.

Autoimmunity involves immune responses directed against self, which are a result of defective self/foreign distinction of the immune system, leading to proliferation of self-reactive lymphocytes, and is characterized by systemic, as well as tissue-specific, inflammation. Numerous mechanisms operate to ensure the immune tolerance to self-antigens. However, monogenetic defects or genetic variants that weaken immune tolerance render susceptibility to the loss of immune tolerance, which is further triggered by environmental factors. In this review, we discuss the phenomenon of immune tolerance, genetic and environmental factors that influence the immune tolerance, factors that induce autoimmunity such as epigenetic and transcription factors, neutrophil extracellular trap formation, extracellular vesicles, ion channels, and lipid mediators, as well as costimulatory or coinhibitory molecules that contribute to an autoimmune response. Further, we discuss the cellular and molecular mechanisms of autoimmune tissue injury and inflammation during systemic lupus erythematosus and lupus nephritis.

Podocyte mitosis - a catastrophe.

Podocyte loss plays a key role in the progression of glomerular disorders towards glomerulosclerosis and chronic kidney disease. Podocytes form unique cytoplasmic extensions, foot processes, which attach to the outer surface of the glomerular basement membrane and interdigitate with neighboring podocytes to form the slit diaphragm. Maintaining these sophisticated structural elements requires an intricate actin cytoskeleton. Genetic, mechanic, and immunologic or toxic forms of podocyte injury can cause podocyte loss, which causes glomerular filtration barrier dysfunction, leading to proteinuria. Cell migration and cell division are two processes that require a rearrangement of the actin cytoskeleton; this rearrangement would disrupt the podocyte foot processes, therefore, podocytes have a limited capacity to divide or migrate. Indeed, all cells need to rearrange their actin cytoskeleton to assemble a correct mitotic spindle and to complete mitosis. Podocytes, even when being forced to bypass cell cycle checkpoints to initiate DNA synthesis and chromosome segregation, cannot complete cytokinesis efficiently and thus usually generate aneuploid podocytes. Such aneuploid podocytes rapidly detach and die, a process referred to as mitotic catastrophe. Thus, detached or dead podocytes cannot be adequately replaced by the proliferation of adjacent podocytes. However, even glomerular disorders with severe podocyte injury can undergo regression and remission, suggesting alternative mechanisms to compensate for podocyte loss, such as podocyte hypertrophy or podocyte regeneration from resident renal progenitor cells. Together, mitosis of the terminally differentiated podocyte rather accelerates podocyte loss and therefore glomerulosclerosis. Finding ways to enhance podocyte regeneration from other sources remains a challenge goal to improve the treatment of chronic kidney disease in the future.

Association study of IRAK-M and SIGIRR genes with SLE in a large European-descent population.

OBJECTIVE: The aim of this study was to evaluate the relevance of genetic variants of interleukin receptor-associated kinase-M (IRAK-M) (rs11465955, rs1624395, rs1152888 and rs1370128) and single immunoglobulin IL1-1R-related molecule (SIGIRR) (rs3210908) genes in systemic lupus erythematosus (SLE) in four independent European-descent populations. METHODS: Our study population consisted of a total of 2033 SLE patients and 2357 healthy controls from Spain, Germany, Italy and Argentina. The genotyping was performed using a polymerase chain reaction (PCR) system with pre-developed TaqMan allelic discrimination assay. Genetic association between the genotyped markers was determined by PLINK v1.07. RESULTS: After a meta-analysis including these four populations, a trend of association between rs11465955 (P(meta) (-analysis) = 0.06), rs1370128 (P(meta) (-analysis) = 0.07) and rs1624395 (P(meta) (-analysis) = 0.06) polymorphisms was found. However, these differences did not reach statistical significance. In addition, we did not find any association between SLE and the rs1152888 IRAK-M (P(meta) (-analysis) = 0.13) and the rs3210908 SIGIRR (P(meta) (-analysis) = 0.40) polymorphisms after the meta-analysis. No evidence of association with IRAK-M haplotypes was found. CONCLUSION: These results suggest that the tested variations of IRAK-M and SIGIRR genes do not confer a relevant role in the susceptibility to SLE in European-descent populations.

Podocytes produce homeostatic chemokine stromal cell-derived factor-1/CXCL12, which contributes to glomerulosclerosis, podocyte loss and albuminuria in a mouse model of type 2 diabetes.

AIMS/HYPOTHESIS: Chemokine (C-X-C motif) ligand 12 (CXCL12) (also known as stromal cell-derived factor-1 [SDF-1]-alpha) is a homeostatic chemokine with multiple roles in cell homing, tumour metastasis, angiogenesis and tissue regeneration after acute injuries. However, its role in chronic diseases remains poorly defined, e.g. in chronic glomerular diseases like diabetic glomerulosclerosis. We hypothesised that CXCL12 may have a functional role during the evolution of diabetic glomerulosclerosis, either by assisting glomerular repair or by supporting the maladaptive tissue remodelling in response to hyperglycaemia and glomerular hyperfiltration. METHODS: To define the functional role of CXCL12 in the progression of glomerular disease, we used the CXCL12-specific inhibitor NOX-A12, an L: -enantiomeric RNA oligonucleotide (Spiegelmer). A mouse model of type 2 diabetes (db/db mice) was used. Male db/db mice, uni-nephrectomised at 6 weeks of age, received subcutaneous injections with a PEGylated form of NOX-A12, non-functional control Spiegelmer or vehicle on alternate days from 4 to 6 months of age. RESULTS: Immunostaining localised renal CXCL12 production to glomerular podocytes in db/db mice with early or advanced diabetic nephropathy. CXCL12 inhibition significantly reduced the degree of glomerulosclerosis, increased the number of podocytes, prevented the onset of albuminuria and maintained the peritubular vasculature without affecting blood glucose levels, body weight or glomerular macrophage infiltration. CONCLUSIONS/INTERPRETATION: We conclude that podocytes produce CXCL12, which contributes to proteinuria and glomerulosclerosis in our mouse model of type 2 diabetes. This novel pathomechanism provides the first evidence that CXCL12 could be a therapeutic target in (diabetic) glomerulosclerosis.

[A 68-year-old patient with atrial flutter/fibrillation, inadequate anticoagulation, subacute amaurosis, normal ESR, and lymphadenopathy]. / 68-jähriger Patient mit Vorhofflattern/Vorhofflimmern, inadäquater Antikoagulation, subakuter Amaurosis, normaler BSG und Lymphadenopathie.

We present a rare manifestation of chronic lymphatic leukemia with progressive bilateral visual loss and the typical fundoscopic picture of anterior ischemic optic nerve neuropathy (AION). Clinical symptoms were due to meningeal metastases and tumor cell infiltration of the optic nerve. The diagnostic clue was provided by lumbar puncture with pressure measurement, which made it possible to differentiate AION from papillitis and papilledema. In this case the patient was able to regain his initial visual activity after intrathecal and systemic polychemotherapy.

[CCL2/MCP1: a novel target in systemic lupus erythematosus and lupus nephritis]. / CCL2/MCP-1 als neues Target beim systemischen Lupus erythematodes und der Lupusnephritis.

Cytokine blockade, a valid therapeutic concept, is not established in lupus nephritis as yet. In lupus nephritis CCL2/MCP-1 and its chemokine receptor CCR2 are of interest because CCL2/CCR2 mediate the recruitment of macrophages and T cells in the nephritic kidney. Lupus nephritis is markedly attenuated in CCL2- or CCR2-deficient autoimmune mice. Epidemiological studies addressing mutations in the CCL2 gene support the hypothesis that CCL2 mediates renal inflammation. Meanwhile experimental studies have shown that several classes of CCL2 antagonists can control established lupus nephritis. Interestingly, therapeutic CCL2 blockade does not affect the autoimmune lymphoproliferative syndrome and the production of lupus autoantibodies. This article briefly summarizes the potential role of therapeutic CCL2 blockade in lupus nephritis.

Tubular atrophy, interstitial fibrosis, and inflammation in type 2 diabetic db/db mice. An accelerated model of advanced diabetic nephropathy.

OBJECTIVE: Advanced diabetic nephropathy (DN) is difficult to address experimentally in mice because available models of DN lack global glomerulosclerosis and major tubulointerstitial pathology. Accelerating the development of DN in mice would be desirable for feasible experimental validation of potential targets that mediate the progression to late stage DN. METHODS: 6 week old male db/db mice underwent uninephrectomy and the development of nephropathy was compared to wild-type mice and sham-operated db/db mice. RESULTS: Uninephrectomy at young age was associated with increased albuminuria and severe glomerulosclerosis in 37% of glomeruli at 24 weeks of age as compared to sham-operated db/db mice (8%). Uninephrectomy also increased the number of glomerular macrophages in db/db mice. The uninephrectomy-related acceleration of glomerular damage was associated with significant tubulointerstitial injury as indicated by an increase in indices of tubular cell damage, tubular dilatation, and expansion of interstitial volume. Uninephrectomy markedly increased the renal mRNA expression of Mcp-1/Ccl2, Tgf-beta, and collagen I. CONCLUSION: Early uninephrectomy can accelerate the development of advanced DN in db/db mice which may be instrumental in the design of interventional studies that intend to focus on the molecular pathology of the progression to late stage DN.

Innate pathogen recognition in the kidney: toll-like receptors, NOD-like receptors, and RIG-like helicases.

How do infections trigger or aggravate renal pathology? The discovery of the toll-like receptors, and more recently, the retinoic-acid-inducible protein-like helicases and the nucleotide-binding oligomerization domain-like receptors may offer new concepts to answer this question. Common pathogen-associated molecules are recognized by these receptors in several cellular compartments of immune cells and non-immune cells inside the kidney. This article summarizes ligand-receptor interactions and their known or potential significance in kidney diseases.

Different roles of TiR8/Sigirr on toll-like receptor signaling in intrarenal antigen-presenting cells and tubular epithelial cells.

Toll-like receptors (TLRs) exist on both myeloid and intrinsic renal cells contributing to the initiation of innate immunity during renal infection with uropathogenic Escherichia coli. Toll-interleukin 1 receptor (IL-1R) (TIR)8/SIGIRR is an orphan receptor of the TLR/IL-1R family, which suppresses TLR signaling of immune cells and is highly expressed in the kidney. Lack of TIR8/SIGIRR is associated with enhanced renal chemokine signaling upon exposure to lipopolysaccharide (LPS). This was because of TIR8/SIGIRR expression on resident intrarenal myeloid cells rather than tubular epithelial cells which express it on basolateral and luminal membranes. The lack of TIR8/SIGIRR does not enhance TLR/IL-1R signaling in tubular epithelial cells as was observed in monocytes. TIR8/SIGIRR is induced in monocytes treated with LPS or tumor necrosis factor and interferon-gamma in a dose-dependent manner but was downregulated in treated tubule epithelial cells. This cell type-specific regulation and function did not relate to mRNA splice variants but was associated with N- and O-glycosylation of the receptor in renal cells of myeloid and nonmyeloid origin. Our studies show that resident myeloid cells contribute to TLR-mediated antimicrobial immunity in the kidney and that this function is controlled by Tir8/sigirr. TIR8/SIGIRR does not suppress TLR signaling in tubular epithelial cells, which supports their role as sensors of microbial infection in the kidney.

Lupus nephritis.

Lupus nephritis is a common complication of systemic lupus erythematosus (SLE). Early recognition of lupus nephritis requires routine serum creatinine determination, urinalysis and urinary microscopy. Since mild urinary abnormalities such as leucocyturia or proteinuria can be associated with severe lupus nephritis, a renal biopsy is usually indicated in patients with SLE and urinary abnormalities. A renal biopsy is required to determine the class of lupus nephritis which is based on histopathological criteria which have recently been revised. Aggressive immunosuppressive therapy is indicated in diffuse proliferative lupus nephritis. In class III or class V the treatment indication depends on additional prognostic criteria. Intravenous cyclophosphamide is still used but doses and intervals have been modified based on large clinical trials. Mycopheno-late may establish as an alternative for cyclophosphamide in the induction phase, but the data of the transcontinental multicenter Aspreva Lupus Management Study (ALMS) trial have not yet been published in detail. Controlled clinical trials support the use of azathioprine and mycophenolate for maintaining remission of lupus nephritis, and cyclophosphamide is no longer used in that phase. Additional control of cardiovascular risk factors and combined angiotensin and angiotensin receptor blockade are mandatory for all proteinuric SLE patients. Novel treatment options are ahead of us based on the molecular mechanisms of SLE and lupus nephritis, but as evidence from controlled clincial trials is still lacking they are not yet approved for broad clinical use. However, the treatment options for severe lupus nephritis have been improved and are likely to further improve in the near future.

Gastrointestinal manifestations associated with systemic lupus erythematosus.

Gastrointestinal symptoms are often difficult to interpret in patients with systemic lupus erythematosus. Symptoms can develop either from symptomatic autoimmune tissue injury, complications of lupus-related organ dysfunction, infections, thrombembolic manifestations of anti-phospholipid antibody syndrome, medication or unrelated disorders. We describe the gastrointestinal manifestations of lupus and discuss the diagnostic approach and therapy.

[Chronic renal failure]. / Neue Konzepte bei der chronischen Niereninsuffizienz.

The elevated cardiovascular mortality seen in patients with renal insufficiency makes it imperative that this condition be detected and treated in good time. The results of recent studies have led to fundamental changes in the therapeutic approach to the patient with kidney disease. A range of new medications is now available for the treatment of complications of renal failure.

Multipotent mesenchymal stem cells reduce interstitial fibrosis but do not delay progression of chronic kidney disease in collagen4A3-deficient mice.

Multipotent mesenchymal stem or stromal cells (MSC) have shown to improve outcome of acute renal injury models, but whether MSC can delay renal failure in chronic kidney disease is not known. We injected primary MSC or saline into mice that lack the alpha3-chain of type IV collagen (COL4A3), a model of chronic kidney disease with close similarities to human Alport disease. Weekly injections of MSC from week 6 to 10 of life prevented the loss of peritubular capillaries and reduced markers of renal fibrosis, that is, interstitial volume, numbers of smooth muscle actin-positive interstitial cells, and interstitial collagen deposits as compared to saline-injected COL4A3-deficient mice. However, renal function, that is, blood urea nitrogen, creatinine levels, proteinuria as well as survival of COL4A3-deficient mice were not affected by MSC injections. Although MSC were found to localize to kidneys of COL4A3-deficient mice after injection, differentiation into renal cells was not detected. However, MSC expressed growth factors, that is, vascular endothelial growth factor (VEGF) and bone morphogenetic protein-7 under basal culture conditions. In fact, VEGF mRNA levels were increased in kidneys of MSC-injected COL4A3-deficient mice and MSC supernatants enhance endothelial cell proliferation in vitro. Thus, weekly injections with MSC prevent loss of peritubular capillaries possibly owing to local production of growth factors rather than by differentiation into renal cells. The maintenance of interstitial vasculature is associated with less interstitial fibrosis but, is insufficient to delay renal failure and survival of COL4A3-deficient mice.

Progression of kidney disease: blocking leukocyte recruitment with chemokine receptor CCR1 antagonists.

Chronic kidney disease (CKD) is usually associated with interstitial leukocytic cell infiltrates, which may contribute to disease progression by production of proinflammatory, proapoptotic, and profibrotic mediators. Recruiting leukocytes into the kidney involves local expression of chemotactic cytokines, that is, chemokines, that interact with respective chemokine receptors on the leukocyte's outer surface. Thus, specific chemokine receptor antagonists may represent an attractive therapeutic concept to interfere with renal leukocyte recruitment. Among the proinflammatory chemokine receptors, chemokine receptor (CCR)-1 has nonredundant roles for leukocyte adhesion to activated vascular endothelium and for transendothelial migration. In fact, blocking CCR-1 with specific small-molecule antagonists was shown to retard progression in various types of rodent CKD models. Here we discuss the perspective of CCR-1 as a new potential target for the treatment of CKD.

A Toll for lupus.

Toll-like receptor (TLR)-9 recognizes CpG motifs in microbial DNA. TLR9 signalling stimulates innate antimicrobial immunity and modulates adaptive immune responses including autoimmunity against chromatin, e.g., in systemic lupus erythematosus (SLE). This review summarizes the available data for a role of TLR9 signalling in lupus and discusses the following questions that arise from these observations: 1) Is CpG-DNA/TLR9 interaction involved in infection-induced disease activity of lupus? 2) What are the risks of CpG motifs in vaccine adjuvants for lupus patients? 3) Is TLR9 signalling involved in the pathogenesis of lupus by recognizing self DNA?

[Psoriatic onycho-pachydermo- periostitis]. / Psoriatische Onycho-Pachydermo-Periostitis.

BACKGROUND: Psoriatic onycho-pachydermo-periostitis is a rare manifestation of psoriatic arthritis. It is characterized by the trias of psoriatic onychosis, tender soft tissue thickening, and osteoperiostitis of the distal phalanges in the absence of distal interphalangeal arthritis. Recommendations for the treatment of symptomatic POPP are not available. AIM OF THE STUDY: Treatment of a symptomatic 49-year old male. METHODS: Sulfasalazine 1000mg b.i.d., p.o. for 8 months followed by radiotherapy of both hands with 6x0.5 Gy. RESULTS: No clinical response was observed with either of the two treatments. CONCLUSIONS: The course of this single case does not support sulfasalazine treatment or radiotherapy in psoriatic onycho-pachydermo-periostitis.