Hypertension and mild chronic kidney disease persist following severe haemolytic uraemic syndrome caused by Shiga toxin-producing Escherichia coli O104:H4 in adults.

BACKGROUND: Shiga toxin-producing, enteroaggregative Escherichia coli was responsible for the 2011 outbreak of haemolytic uraemic syndrome (HUS). The present single-centre, observational study describes the 1-year course of the disease with an emphasis on kidney function. Outcome data after 1 year are associated with treatment and patient characteristics at onset of HUS. METHODS: Patients were treated according to a standardized approach of supportive care, including a limited number of plasmapheresis. On top of this treatment, patients with severe HUS (n = 35) received eculizumab, a humanized anti-C5 monoclonal antibody inhibiting terminal complement activation. The per-protocol decision--to start or omit an extended therapy with eculizumab accompanied by azithromycin--separated the patients into two groups and marked Day 0 of the prospective study. Standardized visits assessed the patients' well-being, kidney function, neurological symptoms, haematological changes and blood pressure. RESULTS: Fifty-six patients were regularly seen during the follow-up. All patients had survived without end-stage renal disease. Young(er) age alleviated restoring kidney function after acute kidney injury even in severe HUS. After 1 year, kidney function was affected with proteinuria [26.7%; 95% confidence interval (CI) 13.8-39.6], increased serum creatinine (4.4%, CI 0.0-10.4), increased cystatin C (46.7%, CI 32.1-61.3) and reduced (<90 mL/min) estimated glomerular filtration rate (46.7%, CI 32.1-61.3). Nine of the 36 patients without previous hypertension developed de novo hypertension (25%, CI 10.9-39.1). All these patients had severe HUS. CONCLUSIONS: Although shiga toxin-producing Escherichia coli (STEC)-HUS induced by O104:H4 was a life-threatening acute disease, follow-up showed a good recovery of organ function in all patients. Whereas kidney function recovered even after longer duration of dialysis, chronic hypertension developed after severe HUS with neurological symptoms and could not be prevented by the extended therapy.

Lack of difference in acute nephrotoxicity of intravenous bisphosphonates zoledronic acid and ibandronate in women with breast cancer and bone metastases.

BACKGROUND: More than 50% of patients with advanced breast cancer develop bone metastases that may lead to multiple complications such as pathological fractures, bone pain or hypercalcaemia. The standard treatment, besides endocrine, targeted-therapy or chemotherapy, is the use of bisphosphonates. However, one of their main adverse side-effects is bisphosphonate-induced nephrotoxicity. The mechanism by which the latter occurs is not well-understood, although emerging evidence suggests that the effect of bisphosphonates on the kidney may differ between agents. PATIENTS AND METHODS: The aim of this evaluation was to compare the renal toxicity of 6 mg ibandronate i.v. versus 4 mg zoledronic acid i.v. over a period of six months in women with breast cancer and bone metastases. A prospective randomized trial was carried out to examine specific kidney and other parameters (α1- and ß2-microglobulin, albumin, α2-macroglobulin, IgG and C-reactive protein (CRP) generated from spontaneous urine samples from 17 patients of each group. RESULTS: We were unable to find any significant difference between the two treatment groups with regard to renal toxicity. All patients, independently of the applied bisphosphonate, experienced only temporary renal dysfunction without any evidence of irreversible damage in terms of acute nephrotoxicity during the study period. α1-Microglobulin, a marker for proximal tubular damage, in particular, was not differently elevated in either group. CONCLUSION: Both applied bisphosphonates were found to be well-tolerated and safe with regard to renal toxicity during a six-month treatment period in patients with otherwise healthy kidneys having advanced breast cancer and bone metastases.

Best supportive care and therapeutic plasma exchange with or without eculizumab in Shiga-toxin-producing E. coli O104:H4 induced haemolytic-uraemic syndrome: an analysis of the German STEC-HUS registry.

BACKGROUND: May 22nd marks the beginning of a Shiga-toxin-producing Escherichia coli (STEC) O104:H4 outbreak in Northern Germany. By its end on 27 July, it had claimed 53 deaths among 2987 STEC and 855 confirmed haemolytic-uraemic syndrome (HUS) cases. METHODS: To describe short-term effectiveness of best supportive care (BSC), therapeutic plasma exchange (TPE) and TPE with eculizumab (TPE-Ecu) in 631 patients with suspected HUS treated in 84 hospitals in Germany, Sweden and the Netherlands using the web-based registry of the DGfN (online since 27 May). RESULTS: Of 631 entries, 491 fulfilled the definition of HUS (median age 46 years; 71% females). The median (inter-quartile range) hospital stay was 22 (14-31) days. Two hundred and eighty-one (57%) patients underwent dialysis and 114 (23%) mechanical ventilation. Fifty-seven patients received BSC, 241 TPE and 193 TPE-Ecu. Treatment strategy was dependent on disease severity (laboratory signs of haemolysis, thrombocytopenia, peak creatinine level, need for dialysis, neurological symptoms, frequency of seizures) which was lower in BSC than in TPE and TPE-Ecu patients. At study endpoint (hospital discharge or death), the median creatinine was lower in BSC [1.1 mg/dL (0.9-1.3)] than in TPE [1.2 mg/dL (1.0-1.5), P < 0.05] and TPE-Ecu [1.4 mg/dL (1.0-2.2), P < 0.001], while need for dialysis was not different between BSC (0.0%, n = 0), TPE (3.7%; n = 9) and TPE-Ecu (4.7%, n = 9). Seizures were absent in BSC and rare in TPE (0.4%; n = 1) and TPE-Ecu (2.6%; n = 5) patients. Total hospital mortality in HUS patients was 4.1% (n = 20) and did not differ significantly between the TPE and TPE-Ecu groups. CONCLUSIONS: Despite frequent renal impairment, advanced neurological disorders and severe respiratory failure, short-term outcome was better than expected when compared with previous reports. Within the limitations of a retrospective registry analysis, our data do not support the notion of a short-term benefit of Ecu in comparison to TPE alone in the treatment of STEC-HUS. A randomized trial comparing BSC, TPE and Ecu seems to be prudent and necessary prior to establishing new treatment guidelines for STEC-HUS.

Association between azithromycin therapy and duration of bacterial shedding among patients with Shiga toxin-producing enteroaggregative Escherichia coli O104:H4.

CONTEXT: An outbreak of Shiga toxin-producing enteroaggregative Escherichia coli (STEC O104:H4) infection with a high incidence of hemolytic uremic syndrome (HUS) occurred in Germany in May 2011. Antibiotic treatment of STEC infection is discouraged because it might increase the risk of HUS development. However, antibiotic therapy is widely used to treat enteroaggregative E coli infection. In the German outbreak, a substantial number of patients received prophylactic azithromycin treatment as part of a therapeutic regimen with the C5 antibody eculizumab. OBJECTIVE: To analyze the duration of bacterial shedding in patients with STEC infection who did and did not receive oral azithromycin therapy. DESIGN, SETTING, AND PATIENTS: At a single center in Lübeck, Germany, 65 patients with STEC infection, including patients with HUS as well as STEC-infected outpatients without manifestation of HUS, were investigated between May 15 and July 26, 2011, and were monitored for a mean of 39.3 days after onset of clinical symptoms. MAIN OUTCOME MEASURE: Carriage of STEC after azithromycin therapy. RESULTS: Twenty-two patients received oral azithromycin and 43 patients did not receive antibiotic treatment. Among antibiotic-treated patients, long-term STEC carriage (>28 days) was observed in 1 of 22 patients (4.5%; 95% CI, 0%-13.3%) compared with 35 of 43 patients (81.4%; 95% CI, 69.8%-93.0%) who were not treated with antibiotics (P < .001). All 22 patients receiving azithromycin treatment had at least 3 STEC-negative stool specimens after the completion of treatment, and no recurrence of STEC was observed in these patients. As proof of principle, 15 patients who initially were not treated with antibiotics and were long-term STEC carriers were treated with oral azithromycin given for 3 days and subsequently had negative stool specimens. CONCLUSION: Treatment with azithromycin was associated with a lower frequency of long-term STEC O104:H4 carriage.

[Resistant hypertension despite nine different antihypertensive drugs?]. / Therapierefraktärer Hypertonus unter 9-facher antihypertensiver Medikation?

BACKGROUND: Treatment-resistant hypertension is a common problem in an outpatient setting and often results in hospital admission. Non-identified secondary hypertension, hypertensive nephrosclerosis and non-compliance are major reasons for treatment resistance. CASE REPORT: A 75-year old woman was admitted to the emergency room because of a hypertensive crisis with alleged treatment-resistant hypertension and progressive headache. Two months ago, renal artery stenosis had been ruled out and a diagnosis of hypertensive cardiomyopathy was established. On admission, the patient had a blood pressure of 210/100 mmHg despite an antihypertensive treatment with nine different drugs. Further investigations ruled out secondary hypertension due to an endocrine cause but were consistent with hypertensive nephrosclerosis. With a supervised drug intake the blood pressure was rather normal to hypotensive, resulting in the need for significant reduction of the antihypertensive medication. The apparent discrepancies were discussed in detail with the patient who finally admitted a previous inconsistent intake of the antihypertensive drugs. Following thorough training and education on the purpose of continued antihypertensive therapy, the patient could be discharged with a normotensive blood pressure profile. CONCLUSIONS: Therapy of treatment-resistant hypertension should always consider non-compliance and secondary hypertension as possible reason.

[Acute and chronic renal insufficiency. Diagnostics and practical implications]. / Akutes und chronisches Nierenversagen. Diagnostik und Folgen für die Praxis.

A newly diagnosed renal insufficiency should be investigated thoroughly, since even slight elevations of renal retention parameters reflect a relevant loss of renal function. Acute creatinine elevations above 0.3 mg/dl are considered an acute kidney injury. Renal failure can be classified according to different criteria. Generally, an acute kidney injury should be separated from chronic renal failure leading to different diagnostic and therapeutic consequences. In most cases, some easy procedures (history, ultrasound, blood tests) help to differentiate between acute and chronic failure. While adequate therapy results in restitution of acute kidney injury in most cases, the aim in chronic renal failure is to minimize complications and to delay renal replacement therapy. Therefore, it is mandatory to involve renal specialists as it has been shown that early referral to nephrologists can ameliorate renal morbidity and mortality. Except for postrenal causes of renal deterioration the diagnostic and therapeutic work-up should be done by nephrologists to avoid unnecessary complications and expenses.

Insulin inhibits caspase-3 activity in human renal tubular epithelial cells via the PI3-kinase/Akt pathway.

Apoptotic mechanisms in proximal renal tubular epithelial cells (PTEC) are crucial in the pathogenesis of acute kidney injury. We investigated whether insulin alters anti-apoptotic signalling in human PTEC. Cells were deprived of insulin for 0, 24 or 48 h and then stimulated with insulin for 0 or 5 min. Apoptosis was induced by camptothecin incubation. Insulin receptor kinase (IR-kinase) activity, phosphorylation of insulin receptor substrate-1 (IRS-1), IRS-1-associated PI3-kinase (p85), Ser(273)-phosphorylation of Akt and caspase-3 activity (C3-activity) were determined. Insulin stimulation increased the activity of IR-kinase, IRS-1 phosphorylation, p85 association with IRS-1 and Ser(273)-phosphorylation of Akt by at least 250%, respectively and decreased the C3-activity by 45% (p < 0.01, respectively). Deprivation of insulin for 24 and 48 h reduced basal and insulin-stimulated IR-kinase activity, IRS-1 phosphorylation, p85 association with IRS-1 and Ser(273)-phosphorylation of Akt by 30-40% and increased C3-activity by 15-20% (p < 0.01, respectively). Incubation with camptothecin increased C3-activity by 250-300% (p < 0.001). Subsequent insulin stimulation reversed the camptothecin induced increase of C3-activity. Our data indicate that apoptosis in PTEC is regulated by the insulin dependent PI3-kinase/Akt pathway. The enhancement of tubular-specific cell survival signals might represent a potential therapeutic tool for the protection of renal function in acute kidney injury.

Cells differentiated from mouse embryonic stem cells via embryoid bodies express renal marker molecules.

Differentiation of mouse embryonic stem (ES) cells via embryoid bodies (EB) is established as a suitable model to study cellular processes of development in vitro. ES cells are known to be pluripotent because of their capability to differentiate into cell types of all three germ layers including germ cells. Here, we show that ES cells differentiate into renal cell types in vitro. We found that genes were expressed during EB cultivation, which have been previously described to be involved in renal development. Marker molecules characteristic for terminally differentiated renal cell types were found to be expressed predominantly during late stages of EB cultivation, while marker molecules involved in the initiation of nephrogenesis were already expressed during early steps of EB development. On the cellular level--using immunostaining--we detected cells expressing podocin, nephrin and wt-1, characteristic for differentiated podocytes and other cells, which expressed Tamm-Horsfall protein, a marker for distal tubule epithelial cells of kidney tissue. Furthermore, the proximal tubule marker molecules renal-specific oxido reductase, kidney androgen-related protein and 25-hydroxyvitamin D3alpha-hydroxylase were found to be expressed in EBs. In particular, we could demonstrate that cells expressing podocyte marker molecules assemble to distinct ring-like structures within the EBs. Because the differentiation efficiency into these cell types is still relatively low, application of fibroblast growth factor (FGF)-2 in combination with leukaemia inhibitory factor was tested for induction, but did not enhance ES cell-derived renal differentiation in vitro.

Expression of C-reactive protein by renal cell carcinomas and unaffected surrounding renal tissue.

BACKGROUND: Elevation of plasma C-reactive protein (CRP) is common in patients with renal cell carcinoma (RCC). Renal tubular epithelial cells are capable of synthesizing CRP. Although production of interleukin (IL)-6 has been described in RCC, CRP expression by carcinoma cells has yet not been investigated. METHODS: In the present study we analyzed CRP plasma levels as well as intratumoral CRP and IL-6 expression of RCC from 40 patients who underwent radical nephrectomy by means of quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. For each tumor, specimens were obtained from tumor center, tumor margin, and unaffected surrounding renal tissue. RESULTS: Preoperative plasma CRP levels correlated significantly with tumor stage (P = 0.05) and grade (P < 0.01). CRP mRNA expression was detected in 26 of 33 (79%), 30 of 36 (83%), and 32 of 36 (89%) samples from tumor center, tumor margin, and unaffected surrounding tissue, respectively. However, levels of CRP mRNA were significantly higher in tumor tissue compared to adjacent renal tissue (P < 0.01). Clear cell carcinoma exhibited significantly higher CRP mRNA levels than papillary carcinoma (P < 0.05). CRP plasma levels correlated significantly with quantitative levels of CRP mRNA within tumors (P < 0.0001). Immunohistochemically, strong CRP production was observed both in tumor cells and in tubular epithelial cells in unaffected tissue, respectively. All kidneys expressed IL-6 mRNA in the tumor and/or the unaffected tissue, but levels of intratumoral IL-6 mRNA showed no significant correlation with CRP plasma levels or local CRP transcription. CONCLUSION: In patients with RCC, a tumor-derived origin of some plasma CRP is likely. Activity of the IL-6/CRP network in RCC contributes to the accumulating evidence of the acute-phase reaction as a local inflammatory process.

Time course and frequency of Epstein-Barr virus reactivation after kidney transplantation: linkage to renal allograft rejection.

The onset and frequency of Epstein-Barr virus (EBV) reactivation after kidney transplantation are unknown. By use of quantitative real-time polymerase chain reaction measurements, evidence of early EBV reactivation, occurring within the first week after the initiation of immunosuppressive therapy (median, 3 days), was observed in 13 of 23 patients, of whom 10 subsequently developed rejection episodes after 2-45 days (median, 5 days). By contrast, rejection was only diagnosed in 1 of 10 patients who did not show signs of viral reactivation. We suggest that EBV reactivation may induce a T cell response that, through the phenomenon of allo-cross-reactivity, could play a critical role in graft rejection.

Molecular parameters for precise diagnosis of asymptomatic Epstein-Barr virus reactivation in healthy carriers.

Asymptomatic Epstein-Barr virus (EBV) reactivations periodically occur in oral mucosa-associated lymphoid tissues. Until now, EBV reactivation has been diagnosed by serologic profiles that suggest virus replication. Serologic responses, however, are delayed and do not necessarily indicate ongoing replicative activity. The aim of the present study was to establish in healthy carriers parameters for a molecular diagnosis of reactivated EBV infection. Recent studies emphasized the association of an increase in peripheral-B-cell viral load with replicative activity at remote sites. Therefore, real-time PCR was used to quantitate EBV genomes in the peripheral blood mononuclear cells (PBMC) (viral load) and plasma samples (viremia) of 22 healthy EBV-seropositive blood donors over a period of 15 months. Furthermore, transcription of the immediate-early gene encoding BZLF1 was investigated in the PBMC of all volunteers. Serology suggested reactivation in nine donors, of whom all but one showed at least once a significant increase in viral load. Another five individuals also exhibited significant changes in viral load but no serologic response. Of the 13 volunteers with significant increases in viral load, 6 had a period of viremia accompanying the rise in viral load. A stable viral load without viremia and negative serology was seen in eight adults. BZLF1 mRNA was undetectable throughout. We conclude that for healthy subjects serology underestimates the frequency of asymptomatic EBV reactivations. Prospective examination of peripheral viral load and viremia is suitable for the exact diagnosis of EBV reactivation, which might be of advantage for immunocompromised patients in whom EBV reactivations are considerably harmful.

Local generation of C-reactive protein in diseased coronary artery venous bypass grafts and normal vascular tissue.

BACKGROUND: Venous coronary artery bypass grafts (CABGs) are prone to accelerated atherosclerosis. In atherosclerotic diseases, serum C-reactive protein (CRP) levels have become an important diagnostic and prognostic marker. The origin of CRP in this setting remains to be elucidated. METHODS AND RESULTS: Monoclonal anti-CRP identified CRP expression in medial and intimal alpha-actin-positive smooth muscle cells (SMCs) of diseased CABGs with type V and VI lesions and also of native saphenous veins of atherosclerotic individuals. In addition, patent coronary arteries with type IV and V but not with type I through III lesions exhibited intense SMC staining for CRP. Calcified desobliterates of occluded coronary arteries with end-stage disease did not show SMC staining for CRP and were consistently negative for CRP mRNA, as detected by means of real-time polymerase chain reaction. However, CRP mRNA was expressed in 11 of 15 diseased CABGs and also in 10 of 15 native veins. By contrast, only 3 of 18 internal mammary and 4 of 12 radial arteries with virtually no atherosclerosis were positive for CRP mRNA. CONCLUSIONS: CRP is produced by SMCs of atherosclerotic lesions with active disease but not in end-stage plaques. The role of CRP constitutively expressed by normal vascular tissue in vein graft disease has yet to be elucidated.

[CO2 angiography of transplanted kidneys]. / CO2-Angiographie von Transplantatnierenarterien.

PURPOSE: To compare image quality and diagnostic accuracy of carbon dioxide (CO2) and iodinated contrast medium as a contast medium in renal transplant artery angiography. MATERIAL AND METHODS: In this prospective, non-randomized, intra-individual study, we examined 17 patients. Digital subtraction angiography (DSA) was performed first with CO2 to find the optimal projection. Then at least one confirming run was performed with CM ("gold standard"). The quality of the angiographic studies with CO2 and CM and their diagnostic accuracy were compared. Blood creatinine levels were monitored during three days after angiography. RESULTS: Three of four renal transplant artery stenoses were diagnosed correctly with CO2. The false-negative CO2 angiography was due to poor contrast. There were no false-positive results with CO2. Regardless the inferior image quality of CO2 angiography, its positive predictive value was 100%. Renal function was not compromised. CONCLUSION: The primary use of CO2 as a contrast medium for the angiographic evaluation of renal transplant arteries is feasible and practical. It reduces the amount of CM needed. However, in order to confirm the diagnosis, at least one additional series with CM should be performed.

The kidney as a second site of human C-reactive protein formation in vivo.

C-reactive protein (CRP) is the main acute phase reactant in humans. Its production is presumably restricted to the liver but extrahepatic expression by inflamed tissue has not been studied in detail. By real-time PCR and immunohistochemistry we here show that renal cortical tubular epithelial cells (TEC) express CRP mRNA and protein within 6 h after stimulation with conditioned medium (CM) or IL-6, but not IL-1alpha or TNF-alpha. Western blot analysis with monoclonal anti-CRP antibody that recognizes native CRP revealed protein secretion into supernatants of CM-stimulated TEC cultures. While hepatoma-derived Hep3B cells could be induced similarly, peripheral blood mononuclear cells could not. CRP mRNA transcripts were observed in nephrectomized renal allografts with severe acute rejection but not with chronic allograft nephropathy (CAN). Of 19 needle biopsies of acutely rejecting kidney transplants, 15 demonstrated CRP mRNA production with the relative expression levels increasing with the severity of rejection. On the other hand, none of 7 graft biopsies with acute tubular necrosis (ATN) or CAN showed CRP mRNA expression. By using monoclonal anti-CRP antibody, cortical tubules as well as glomerular cells were shown to locally express CRP in rejecting, but not in ATN kidneys. We conclude that inflamed kidneys represent a so far unknown site of CRP formation in vivo. These data shed new light on the acute phase reaction not merely representing a systemic inflammatory pathway but probably being part of the local immune response.