Glomerular endothelial derived vesicles mediate podocyte dysfunction: A potential role for miRNA

MicroRNAs (miRNA) are shown to be involved in the progression of several types of kidney diseases. Podocytes maintain the integrity of the glomerular basement membrane. Extracellular vesicles (EV) are important in cell-to-cell communication as they can transfer cellular content between cells, including miRNA. However, little is known about how extracellular signals from the glomerular microenvironment regulate podocyte activity. Using a non-contact transwell system, communication between glomerular endothelial cells (GEnC) and podocytes was characterised in-vitro. Identification of transferred EV-miRNAs from GEnC to podocytes was performed using fluorescence cell tracking and miRNA mimetics. To represent kidney disease, podocyte molecular profiling and functions were analysed after EV treatments derived from steady state or activated GEnC. Our data shows activation of GEnC alters EV-miRNA loading, but activation was not found to alter EV secretion. EV delivery of miRNA to recipient podocytes altered cellular miRNA abundance and effector functions in podocytes, including decreased secretion of VEGF and increased mitochondrial stress which lead to altered cellular metabolism and cytoskeletal rearrangement. Finally, results support our hypothesis that miRNA-200c-3p is transfered by EVs from GEnC to podocytes in response to activation, ultimately leading to podocyte dysfunction.

Prognosis and future developments in vasculitis

The prognosis of ANCA-associated vasculitis has been transformed in recent years. Once it was a set of invariably acute and fatal conditions, but these disorders are currently considered to be chronic diseases. This change is largely attributable to earlier diagnosis and the careful application of immunotherapeutics. However, patients still experience premature mortality, relapse, comorbid ill health and poor quality of life. Mortality rates in large-vessel vasculitis are not comparable; however, morbidity and poor patient outcomes prevail. Toxicity secondary to glucocorticoids represents a common driver of poor outcomes across systemic vasculitis. The main thrust of future treatment strategies is to reduce if not eliminate exposure to these agents.

European consensus statement on the terminology used in the management of lupus glomerulonephritis

Systemic lupus erythematosus (SLE) is a complex, multisystem autoimmune disorder, which often involves referral to multiple medical specialists. Lupus nephritis (LN) occurs in ~35% of adults with SLE and predicts poor survival. There is currently no consensus on how to manage patients with SLE or LN across specialties and across different European countries. The Lupus Nephritis Terminology Advisory Group was formed to address this issue as it impacts upon LN treatment. It has developed consensus statements based on opinions from expert panel meetings with nephrologists, nephropathologists, rheumatologists, clinical immunologists and internal medicine specialists from many European countries, after reviewing current guidelines from the European League Against Rheumatism, the American College of Rheumatology and the participants’ experience. In this article, we report consensus statements that were developed in six important areas: classification of patients with LN, how classification affects the selection of treatment options and definitions of induction, response, flare and maintenance. We have also proposed a consensus for the terminology involved in the management of LN that is consistent with clinical opinion gathered from multidisciplinary expert meetings and with existing guidelines. We believe this consensus approach provides agreed expert opinion to clinicians and will form the basis for optimising LN treatment.

Severe insulin resistance secondary to insulin antibodies: successful treatment with the immunosuppressant MMF

We have evaluated the use of the immunosuppressant mycophenolate mofetil (MMF) in the treatment of severe insulin resistance caused by neutralising anti-insulin antibodies in type 1 diabetes mellitus (T1DM). A 12-yr-old boy with a 5-month history of T1DM developed severe immunological insulin resistance secondary to human insulin antibodies. Various different treatment modalities, including lispro insulin, intravenous insulin, prednisolone and immunoabsorption, were tried, all without a sustained response to treatment. Although the introduction of the immunosuppressant MMF only resulted in a small reduction in haemoglobin A1c (from 10.9 to 9.8%), it did result in a significant reduction in insulin requirements from 6000 to 250 U/d (75 to 3.1 U/kg/d), disappearance of the severe nocturnal hypoglycaemia associated with high titres of insulin antibodies and a reduction in the level of these antibodies from 34.6 to 2.7 mg/dL. MMF may be considered as a means of immunosuppression in patients with markedly raised insulin antibodies whose diabetes cannot be controlled with insulin alone.

Bone marrow contributes to renal parenchymal turnover and regeneration

In order to establish whether extra-renal cells contribute to the turnover and repair of renal tissues, this study examined kidneys of female mice that had received a male bone marrow transplant and kidney biopsies from male patients who had received kidney transplants from female donors. By using in situ hybridization to detect Y-chromosomes it could be demonstrated that circulating stem cells frequently engraft into the kidney and differentiate into renal parenchymal cells. In the human renal grafts it was confirmed that some of the recipient-derived cells within the kidney exhibited a tubular epithelial phenotype, by combining in situ hybridization with immunostaining for the epithelial markers CAM 5.2 and the lectin Ulex europaeus. Female mouse recipients of male bone marrow grafts showed co-localization of Y-chromosomes and tubular epithelial markers Ricinus communis and Lens culinaris, and a specific cytochrome P450 enzyme (CYP1A2) indicating an appropriate functional capability of clustered newly formed marrow-derived tubular epithelial cells. Y-chromosome-containing cells were observed within glomeruli, with morphology and location appropriate for podocytes. Within the murine kidney, these Y-chromosome-positive cells were negative for the mouse macrophage marker F4/80 antigen and leukocyte common antigen, but were vimentin-positive. The presence of bone marrow-derived cells was noted in both histologically normal mouse kidneys and in human transplanted kidneys suffering damage from a variety of causes. These data indicate that bone marrow cells contribute to both normal turnover of renal epithelia and regeneration after damage, and it is suggested that this could be exploited therapeutically.

Bullous dermatoses in end-stage renal failure: porphyria or pseudoporphyria?

Bullous dermatoses (BD) are well recognized in patients with end-stage renal disease (ESRD). It is important to distinguish pseudoporphyria (porphyrin accumulation due to decreased clearance) from true porphyrias, particularly those in which acute neurological attacks may occur. Investigation of the dialysis patient poses practical diagnostic difficulties because urinary porphyrin profiles are not available. We describe a patient on continuous ambulatory peritoneal dialysis (CAPD) with several recognized causative factors for porphyria cutanea tarda (PCT). The patient presented with a blistering photosensitive rash. We highlight the importance of investigating anuric patients with fractionation of both fecal and plasma porphyrins. Plasma porphyrins were grossly elevated (345 nmol/L; reference range, <13), whereas plasma porphyrins in a control group of CAPD patients without blistering rashes were only minimally elevated (mean, 23.9 nmol/L; SD, 11.0; n = 9). Fractionation of fecal porphyrins by high-performance liquid chromatography (HPLC) yielded a pattern typical of PCT. In addition to the contributory factors for PCT that were present, it is possible that porphyrin accumulation secondary to renal failure played a role in the expression of her disease. Patients with ESRD presenting with BD require careful evaluation, including fractionation of fecal porphyrins.

International Consensus Statement on Testing and Reporting of Antineutrophil Cytoplasmic Antibodies (ANCA)

Antineutrophil cytoplasmic antibody (ANCA) tests are used to diagnose and monitor inflammatory activity in the primary systemic small vessel vasculitides. ANCA is best demonstrated in these diseases by using a combination of indirect immunofluorescence (IIF) of normal peripheral blood neutrophils and enzyme-linked immunosorbent assays (ELISAs) that detect ANCA specific for proteinase 3 (PR3) or myeloperoxidase (MPO). For ANCA testing in "new" patients, IIF must be performed on all serum samples. Serum samples containing ANCA, any other cytoplasmic fluorescence, or an antinuclear antibody (ANA) that results in homogeneous or peripheral nuclear fluorescence then should be tested in ELISAs for PR3-ANCA and MPO-ANCA. Optimally, ELISAs for PR3-ANCA and MPO-ANCA should be performed on all serum samples. Inclusion of the most recent positive sample in the IIF or ELISA may help demonstrate a change in antibody level. Reports should use recommended terms. Any report of positive neutrophil fluorescence issued before the ELISA results are available should indicate that positive fluorescence alone is not specific for the diagnosis of Wegener granulomatosis or microscopic polyangiitis and that decisions about treatment should not be based solely on the ANCA results.

Outcome of renal replacement therapy in antineutrophil cytoplasmic antibody-associated systemic vasculitis

Antineutrophil cytoplasmic antibody-associated systemic vasculitis (AASV) frequently leads to end-stage renal disease (ESRD). Potentially fatal disease activity can continue after the onset of ESRD in both dialysis and transplant patients, despite the immunosuppressive effects of uremia and rejection prophylaxis, leading to concerns that such patients have greater morbidity and mortality. To assess the outcome of AASV patients receiving renal replacement therapy, a retrospective analysis of 59 patients from our unit who received chronic dialysis, renal transplantation, or both, was performed. The survival of AASV patients with ESRD was comparable to national registry controls, as were both graft and patient survival after renal transplantation. Ther is no evidence that standard immunosuppressive protocols should be altered for AASV patients receiving renal transplants. The rate of relapse of vasculitis for patients on chronic dialysis and after transplantation was 0.09 and 0.02 per patient per year, respectively. These rates are lower than those of other series and support the contention that continued immunosuppression after ESRD, as practiced in our unit, is warranted. Relapses usually responded to cyclophosphamide and high-dose prednisolone treatment. Significantly, vasculitic flare-ups in dialysis patients were sometimes initially misdiagnosed as dialysis complications, leading to fatal delays in effective treatment. Follow-up by physicians experienced in the diagnosis and treatment of vasculitis activity should continue in these patients.

Essential mixed cryoglobulinaemia with false-positive serological tests for syphilis

Analysis of serum from a patient with cutaneous leukocytoclastic vasculitis showed a mixed cryoglobulin with a monoclonal IgM kappa-antiglobulin component (6.5 mg/ml), strong rheumatoid factor activity (latex titre 1/5000), and positive serological tests for syphilis (fluorescent treponemal antibody-absorbed and Treponema pallidum haemagglutination assay). After removal of antiglobulin activity by immunoabsorption with heat-aggregated gammaglobulin all serological test results for treponemal infection became negative. Serological tests for syphilis and rheumatoid factor on the supernatant from whole serum (minus cryoglobulin) remained positive though at a lower titre (latex 1/1250). Cryoglobulin isolated from whole serum retained rheumatoid and TPHA reactivity but was negative in the FTA-ABS test. The IgM and IgG cryoglobulin components purified by gel filtration on Sepharose showed no antitreponemal reactivity even when tested individually. Reducing the concentration of cryoglobulin to 1.5 mg/ml by plasma exchange converted the test results for syphilis to doubtful-positive or negative. These results indicated that high concentrations of antiglobulin activity may be associated with falsely positive specific antitreponemal test results and that this phenomenon depends on the concentration of cryoglobulin in the test sample.

Subacute massive pulmonary embolism

Twenty-four patients with subacute massive pulmonary embolism were studied both during their initial illness and up to nine years after it. The most common mode of presentation was progressive dyspnoea over a two to 12 week period, which in some, but not all, patients was accompanied by pleuritic chest pain and haemoptysis. Physical signs at diagnosis usually suggested right heart strain and ventilation/perfusion mismatch and in the five patients with the highest pulmonary artery pressures the pulmonary component of the second sound was accentuated. The chest x-ray and electrocardiogram provided useful diagnostic information in most patients though occasionally they were normal. Early response to thrombolytic treatment was poor when compared with patients with acute pulmonary embolism but was occasionally dramatically successful, and heparin alone provided satisfactory treatment in the eight patients receiving it. Pulmonary embolectomy provided poor results and four of the five patients undergoing this form of treatment died. Nine patients died during the initial illness and in seven death was directly related to embolic disease. One patient died from neoplastic disease during follow-up. Though the prolonged illness, poor initial response to treatment, and absence of predisposing factors suggest that recurrent embolic disease and late pulmonary hypertension might occur three was no evidence of this during a follow-up period of one to nine years (median five years).