Successful immunoadsorption of life-threatening bleeding in factor VIII inhibitor disease, but no long-term remission with anti-CD20 treatment.

A 62-year-old man and a 64-year-old woman presented to our institution with acquired haemophilia A. They both developed life-threatening bleeding. Immunoadsorption using protein A columns was used to rapidly lower factor VIII inhibitor levels. Immunosuppression with steroids and the anti-CD20 antibody, rituximab, was instituted. Yet their effects were either partial or complicated by an early relapse. Repetitive cyclophosphamide administration led to a sustained immunological response. While immunoadsorption appears effective and safe to lower factor VIII inhibitor levels, it seems that further preferably randomised controlled trials are needed to establish the value of rituximab versus the standard immunosuppressive regime comprising cyclophosphamide.

Pulmonary infiltrate and painful nodular leg lesions in a patient with membranous glomerulonephritis.

Nocardia otitidis-cavarium is rarely isolated as an infectious pathogen in the western world. We report on a 71-year-old Caucasian man with membranous glomerulonephritis who presented with several seemingly unrelated clinical symptoms that, after laborious diagnostics, turned out to be caused by disseminated infection with N. otitidis-cavarium. This case highlights the variable clinical presentations that can occur in nocardial infections and underscores the need to search for rare pathogens in patients taking immunosuppressive medication.

Shared decision-making in antihypertensive therapy: a cluster randomised controlled trial.

BACKGROUND: Hypertension is one of the key factors causing cardiovascular diseases. A substantial proportion of treated hypertensive patients do not reach recommended target blood pressure values. Shared decision making (SDM) is to enhance the active role of patients. As until now there exists little information on the effects of SDM training in antihypertensive therapy, we tested the effect of an SDM training programme for general practitioners (GPs). Our hypotheses are that this SDM training (1) enhances the participation of patients and (2) leads to an enhanced decrease in blood pressure (BP) values, compared to patients receiving usual care without prior SDM training for GPs. METHODS: The study was conducted as a cluster randomised controlled trial (cRCT) with GP practices in Southwest Germany. Each GP practice included patients with treated but uncontrolled hypertension and/or with relevant comorbidity. After baseline assessment (T0) GP practices were randomly allocated into an intervention and a control arm. GPs of the intervention group took part in the SDM training. GPs of the control group treated their patients as usual. The intervention was blinded to the patients. Primary endpoints on patient level were (1) change of patients' perceived participation (SDM-Q-9) and (2) change of systolic BP (24h-mean). Secondary endpoints were changes of (1) diastolic BP (24h-mean), (2) patients' knowledge about hypertension, (3) adherence (MARS-D), and (4) cardiovascular risk score (CVR). RESULTS: In total 1357 patients from 36 general practices were screened for blood pressure control by ambulatory blood pressure monitoring (ABPM). Thereof 1120 patients remained in the study because of uncontrolled (but treated) hypertension and/or a relevant comorbidity. At T0 the intervention group involved 17 GP practices with 552 patients and the control group 19 GP practices with 568 patients. The effectiveness analysis could not demonstrate a significant or relevant effect of the SDM training on any of the endpoints. CONCLUSION: The study hypothesis that the SDM training enhanced patients' perceived participation and lowered their BP could not be confirmed. Further research is needed to examine the impact of patient participation on the treatment of hypertension in primary care. TRIAL REGISTRATION: German Clinical Trials Register (DRKS): DRKS00000125.

Implementation of shared decision making by physician training to optimise hypertension treatment. Study protocol of a cluster-RCT.

BACKGROUND: Hypertension is one of the key factors causing cardiovascular diseases which make up the most frequent cause of death in industrialised nations. However about 60% of hypertensive patients in Germany treated with antihypertensives do not reach the recommended target blood pressure. The involvement of patients in medical decision making fulfils not only an ethical imperative but, furthermore, has the potential of higher treatment success. One concept to enhance the active role of patients is shared decision making. Until now there exists little information on the effects of shared decision making trainings for general practitioners on patient participation and on lowering blood pressure in hypertensive patients. METHODS/DESIGN: In a cluster-randomised controlled trial 1800 patients receiving antihypertensives will be screened with 24 h ambulatory blood pressure monitoring in their general practitioners' practices. Only patients who have not reached their blood pressure target (approximately 1200) will remain in the study (T1 - T3). General practitioners of the intervention group will take part in a shared decision making-training after baseline assessment (T0). General practitioners of the control group will treat their patients as usual. Primary endpoints are change of systolic blood pressure and change of patients' perceived participation. Secondary endpoints are changes of diastolic blood pressure, knowledge, medical adherence and cardiovascular risk. Data analysis will be performed with mixed effects models. DISCUSSION: The hypothesis underlying this study is that shared decision making, realised by a shared decision making training for general practitioners, activates patients, facilitates patients' empowerment and contributes to a better hypertension control. This study is the first one that tests this hypothesis with a (cluster-) randomised trial and a large sample size.

Reversible pulmonary hypertension in a kidney transplant with patent A-V fistula.

Pulmonary hypertension (PH) occurs in end-stage renal disease (ESRD) patients on long-term haemodialysis (HD) using an arterio-venous (A-V) access and can be attenuated by either kidney transplantation per se or surgical fistula ligation/revision. We report an exceptional case with severe PH after kidney transplantation due to ESRD and prior chronic intermittent HD via a patent A-V fistula. Gold-standard right heart catheterization findings have-for the first time-proven that following surgical shunt ligation of the A-V fistula, haemodynamics normalized completely in this patient.

Long-term outcome of ABO-incompatible living donor kidney transplantation based on antigen-specific desensitization. An observational comparative analysis.

BACKGROUND: ABO-incompatible living donor kidney transplantation based on specific conditioning has been successfully adopted by transplant centres worldwide. Excellent short-term results have been reported in small cohorts. However, long-term data and comparative analyses are still sparse. We report on the outcome of 40 consecutive ABO-incompatible living donor kidney transplant recipients and compare their clinical course to a control group of 43 ABO-compatible living donor transplant patients transplanted during the same time period. METHODS: This is an observational single-centre analysis of 40 consecutive patients undergoing ABO-incompatible kidney grafting between April 2004 and April 2009, using a protocol of rituximab, antigen-specific immunoadsorption, intravenous immunoglobulin, basiliximab induction and oral triple immunosuppression with tacrolimus, mycophenolic acid and prednisone. Forty-three ABO-compatible kidney transplant recipients served as controls. The control group had also received basiliximab induction and an identical initial maintenance immunosuppression. The two groups were observed for an average of 39 and 19 months, respectively. RESULTS: There was a significantly higher incidence of lymphoceles requiring surgical revisions in the ABO-incompatible group. However, this surgical complication did not affect patient or graft survival. Mean serum creatinine, estimated glomerular filtration rate and proteinuria did not differ between the two groups. Furthermore, ABO-incompatible and ABO-compatible patients had the same incidence of humoral and cellular rejections. Despite a more aggressive induction therapy, no differences in infectious or malignant complications were observed. CONCLUSIONS: ABO-incompatible living donor kidney transplantation utilizing a combination of rituximab and antigen-specific immunoadsorption yielded results identical to ABO-compatible transplantation despite a significantly higher number of human leukocyte antigen mismatches.

Hemofiltration of recombinant hirudin by different hemodialyzer membranes: implications for clinical use.

Recombinant hirudin (lepirudin) is a potent direct thrombin inhibitor that is used particularly for treatment of immune-mediated heparin-induced thrombocytopenia. Because hirudin is almost exclusively eliminated by the kidneys, its half-life is markedly prolonged in patients with severe renal insufficiency. Therefore, these patients are at risk for bleeding, particularly because no antidote is available. To use hirudin safely in patients who are on renal replacement therapy, knowledge of hirudin-sieving characteristics of different hemodialyzers is required. Data on this issue are sparse and in part contradictory. Eight different conventional low-flux and high-flux hemodialyzers were tested in an in vitro circuit with ultrafiltrate reinfusion. In each experiment, lepirudin concentration was repetitively measured during 3 h in the prefilter, the postfilter, and the filtration line using a chromogenic assay. On the basis of these data, sieving coefficients were calculated. All high-flux hemodialyzers tested allowed filtration of hirudin yet with marked differences in steady-state sieving (sieving coefficients in whole blood: polysulfone [PS] 0.97 +/- 0.03; polymethylmethacrylate [PMMA] 0.75 +/- 0.02; polyarylethersulfone 0.73 +/- 0.02; polyamide 0.49 +/- 0.02). None of the low-flux hemodialyzer membranes tested (cuprophane, hemophane, PS, and PMMA) showed significant hirudin filtration. Owing to marked differences in hirudin-sieving characteristics, choice of the appropriate hemodialyzer membrane is an important determinant of bleeding risk in dialysis-dependent patients who are treated with hirudin. In case of overdosage or bleeding complications, hemofiltration via PS membranes is recommended to reduce plasma hirudin concentration. Hirudin dosage should be adapted not only to the clinical situation but also to the hirudin-sieving characteristics of the assigned dialyzer.

Essentials of anticoagulation in hemodialysis.

Numerous acquired hemostatic abnormalities have been identified in renal insufficiency. Hemodialysis procedures add to these disturbances as they repetitively imply turbulent blood flow, high shear stress, and contact of blood to artificial surfaces. This nonphysiological environment leads to activation of platelets, leukocytes, and the coagulation cascade, resulting in fouling of the membrane and ultimately in clotting of fibers and the whole hemodialyzer. Anticoagulation in hemodialysis is targeted to prevent this activation of coagulation during the procedure. Most agents inhibit the plasmatic coagulation cascade. Still commonly used is unfractionated heparin, followed by low-molecular-weight heparin preparations with distinct advantages. Immune-mediated heparin-induced thrombocytopenia constitutes a potentially life-threatening complication of heparin therapy requiring immediate switch to nonheparin alternative anticoagulants. Danaparoid, lepirudin, and argatroban are currently being used for alternative anticoagulation, all of which possess both advantages and limitations. In the past, empirical strategies reducing or avoiding heparin were applied for patients at bleeding risk, whereas nowadays regional citrate anticoagulation is increasingly used to prevent bleeding by allowing procedures without any systemic anticoagulation. Avoidance of clotting within the whole hemodialyzer circuit is not granted. Specific knowledge of the mechanisms of coagulation, the targets of the anticoagulants in use, and their respective characteristics constitutes the basis for individualized anticoagulation aimed at achieving full patency of the circuit throughout the procedure. Patency of the circuit is an important prerequisite for optimal hemodialysis quality.

The direct thrombin inhibitor argatroban: a review of its use in patients with and without HIT.

Argatroban is a synthetic direct thrombin inhibitor with a relative short elimination half-life of 45 minutes and elimination which is predominantly performed via hepatic metabolism. Argatroban anticoagulation has been systematically studied in patients exhibiting the heparin-induced thrombocytopenia (HIT)/thrombosis syndrome and demonstrated to be a safe and effective therapy in this indication. Moreover, in smaller studies argatroban has also been assessed in special clinical settings in non-HIT patients. The current review presents the pharmacology of argatroban, data regarding monitoring of the agent, and an overview of the results of the major clinical trials assessing argatroban anticoagulation in HIT patients. Additionally, data from clinical trials with argatroban use outside HIT, in more special indications such as in percutaneous coronary intervention, stroke, renal replacement therapy, and intensive care medicine, are reviewed.

Functional expression of the renin-angiotensin system in human podocytes.

Experimental and clinical studies impressively demonstrate that angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) significantly reduce proteinuria and retard progression of glomerular disease. The underlying intraglomerular mechanisms are not yet fully elucidated. As podocyte injury constitutes a critical step in the pathogenesis of glomerular proteinuria, beneficial effects of ACEI and ARB may partially result from interference with a local renin-angiotensin system (RAS) in podocytes. The knowledge of expression and function of a local RAS in podocytes is limited. In this study, we demonstrate functional expression of key components of the RAS in differentiated human podocytes: podocytes express mRNA for angiotensinogen, renin, ACE type 1, and the AT(1) and AT(2) angiotensin receptor subtypes. In Western blot experiments and immunostainings, expression of the AT(1) and AT(2) receptor was demonstrated both in differentiated human podocytes and in human kidney cortex. ANG II induced a concentration-dependent increase in cytosolic Ca(2+) concentration via AT(1) receptors in differentiated human podocytes, whereas it did not increase cAMP. Furthermore, ANG II secretion was detected, which was blocked by neither the ACEI captopril nor the renin inhibitor remikiren nor the chymase inhibitor chymostatin. ANG II secretion of podocytes was not increased by mechanical stress. Finally, ANG II was found to increase staurosporine-induced apoptosis in podocytes. We speculate that ACEI and ARB exert their beneficial effects, in part, by interfering with a local RAS in podocytes. Further experiments are required to identify the underlying molecular mechanism(s) of podocyte protection.

The role of recombinant hirudins in the management of thrombotic disorders.

Native hirudin is the most potent natural direct thrombin inhibitor currently known; it is capable of inhibiting not only fluid phase, but also clot-bound thrombin. Recombinant technology now allows production of recombinant hirudins (r-hirudins), which are available in sufficient purity and quantity with essentially unaltered thrombin-inhibitory potency. As thrombin is known to play a key role in a number of thrombotic disorders, numerous studies focused on the impact of r-hirudins on the clinical course in these diseases. R-hirudins provided significantly more stable anticoagulation than standard heparin, but demonstrated a relatively narrow therapeutic range with relevant bleeding risk even at clinically effective doses. In doses that are not associated with an increased bleeding risk, r-hirudins often failed to demonstrate significant superiority to heparin. To date, r-hirudins have a definite role in the treatment of heparin-induced thrombocytopenia, where they markedly reduce the high risk of thrombosis. For prophylaxis of deep vein thrombosis, r-hirudins have been shown to be superior to both unfractionated and low molecular weight heparin, but are not extensively used in this indication. In acute coronary syndromes, a definite role of r-hirudins has not yet been firmly established. When applied in an appropriate dose as adjunct to thrombolysis in patients with acute myocardial infarction, randomized, controlled trials did not show a consistent benefit of r-hirudins, especially in the long-term. In patients undergoing coronary balloon angioplasty for acute coronary syndromes, promising effects in the early postprocedural phase did not translate to an improved outcome after 6 months. In patients with unstable angina pectoris, efficacy and safety of r-hirudins as primary antithrombotic therapy are still under debate. In the future, r-hirudins are to be compared with alternative or additional potent antithrombotic agents or treatment strategies. This comparison will ultimately lead to their final placement in the management of thrombotic disorders.

Anti-hirudin antibodies alter pharmacokinetics and pharmacodynamics of recombinant hirudin.

Recombinant hirudin (r-hirudin) is a potent direct thrombin inhibitor with immunogenic properties. Anti-hirudin antibodies (aHAb) are detected in up to 74% of patients treated with r-hirudin for more than 5 days. aHAb may alter the pharmacokinetics and pharmacodynamics of r-hirudin. The effects of aHAb on the pharmacokinetics of r-hirudin were investigated in rats receiving r-hirudin intravenously either without aHAb (controls), 15 min after intravenous administration of non-specific antibodies or aHAb, and after pre-incubation with aHAb. When both were compared to controls and pre-treatment with non-specific antibodies, aHAb significantly altered the pharmacokinetics of r-hirudin with similar effects in both approaches: In the presence of aHAb, the volume of distribution in a steady state and total plasma clearance were diminished, while the half-life of elimination was prolonged. Both the maximum r-hirudin plasma concentration and the area under the curve were increased. In addition, r-hirudin filtration by high-flux hemodialyzer membranes (polysulfone, AN69) was investigated 1) in the absence of aHAb, 2) in the presence of non-specific mouse antibodies, and 3) in the presence of three monoclonal aHAb. In the absence of aHAb, both hemodialyzers allowed for significant r-hirudin filtration. Non-specific mouse antibodies did not markedly affect r-hirudin filtration. By contrast, all three aHAb almost completely hindered r-hirudin filtration. aHAb varied in their capacity to neutralize r-hirudin. In conclusion, aHAb markedly alter the pharmacokinetics of r-hirudin leading to r-hirudin accumulation. In the presence of aHAb, hemofiltration does not allow for rapid reduction of r-hirudin concentration. aHAb are capable of modifying pharmacodynamics of r-hirudin. Close monitoring of aHAb-positive patients treated with r-hirudin is considered mandatory.

Up-regulation of early growth response gene-1 via the CXCR3 receptor induces reactive oxygen species and inhibits Na+/K+-ATPase activity in an immortalized human proximal tubule cell line.

The CXCR3 chemokine receptor, a member of the CXCR family, has been linked to a pathological role in autoimmune disease, inflammatory disease, allograft rejection, and ischemia. In the kidney, expression of the CXCR3 receptor and its ligands is up-regulated in states of glomerulonephritis and in allograft rejection, but little is known about the expression and functional role the CXCR3 receptor might play. Here, we study the function of the CXCR3 chemokine receptor in an immortalized human proximal tubular cell line (IHKE-1). Stimulation of the CXCR3 receptor by its selective agonist monokine induced by IFN-gamma leads via a Ca(2+)-dependent mechanism to an up-regulation of early growth response gene (EGR)-1. Overexpression of EGR-1 induces down-regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase and stimulates the generation of reactive oxygen species (ROS) via the NADH/NADPH-oxidase system. EGR-1 overexpression or treatment with monokine induced by IFN-gamma resulted in a ROS-dependent inhibition of basolateral Na(+)/K(+)-ATPase activity, compromising sodium transport in these cells. Thus, activation of the CXCR3 receptor in proximal tubular cells might disturb natriuresis during inflammatory and ischemic kidney disease via EGR-1-mediated imbalance of ROS.

Hirudin in renal insufficiency.

Recombinant hirudins (r-hirudins) are potent direct thrombin inhibitors increasingly used for alternative anticoagulation, especially in heparin-induced thrombocytopenia. R-hirudins are almost exclusively eliminated by the kidneys, and a close correlation between r-hirudin clearance and endogenous creatinine clearance has been observed. Accordingly, the pharmacokinetics of r-hirudin are altered in patients with renal insufficiency. A decline of renal r-hirudin clearance is associated with an increase of r-hirudin half-life and the area under the curve (AUC). Therefore, renal impairment necessitates reduction of r-hirudin dose to avoid overdose or inadequate accumulation of the thrombin inhibitor. To this end, close monitoring of r-hirudin anticoagulation is required, which at best is performed by measuring r-hirudin blood levels by ecarin clotting times (ECT) or chromogenic assays, in addition to activated partial thromboplastin time (aPTT). Recent studies showed that r-hirudin anticoagulation is feasible in acute or chronic renal failure treated with continuous or intermittent renal replacement therapy, if appropriate r-hirudin dosing and adequate monitoring are warranted. High-volume hemofiltration with r-hirudin-permeable hemodialyzers constitutes a valuable means to markedly reduce r-hirudin blood concentration and total r-hirudin body content in case of r-hirudin overdose or r-hirudin-associated bleeding. In the future, the hepatically eliminated direct thrombin inhibitor argatroban may facilitate alternative anticoagulation in patients with renal insufficiency.

Biological relevance of anti-recombinant hirudin antibodies--results from in vitro and in vivo studies.

This article provides an overview of the clinically relevant characteristics of antibodies directed toward recombinant (r) hirudin, with emphasis on the different ways in which these antibodies may influence pharmacokinetics and pharmacodynamics of r-hirudin. A high incidence of anti-hirudin antibody (AHAb) formation, mainly of the immunoglobulin G (IgG) subclass, was reported in up to 74% of patients treated with r-hirudin for more than 5 days. Like other drug-induced antibodies, AHAb may be responsible for accumulation or neutralization of the drug. Current clinical data support this assumption with reports on reduced metabolism, enhanced activity, and accumulation and neutralization of r-hirudin in the presence of AHAb. By examining AHAb developed in patients, we were able to demonstrate that AHAbs are capable of neutralizing r-hirudin in vitro. In addition, the anticoagulant activity of r-hirudin administered to Sprague-Dawley rats was almost completely abolished when a monoclonal mouse AHAb with known r-hirudin neutralizing capacity in vitro was injected intravenously. Because r-hirudin is mainly eliminated via the kidneys, formation of r-hirudin-AHAb complexes may, due to their size, result in accumulation of r-hirudin. We investigated filtration of r-hirudin incubated with monoclonal mouse AHAb by using high-flux hemodialyzers in a suitable in vitro model. Whereas sieving coefficients (SC) were high in the absence of AHAb, they were minimal (SC < 0.05) in the presence of AHAb. These findings may also be important when AHAb-positive patients treated with r-hirudin undergo hemofiltration procedures, which have recently been described as a rescue measure in case of r-hirudin overdosage. In vivo, the influence of a non-neutralizing monoclonal mouse AHAb on r-hirudin pharmacokinetics was examined in rats. Pharmacokinetic data compared with those of a control group without AHAb administration revealed that r-hirudin elimination half-life was significantly prolonged (59 +/- 25 minutes versus 142 +/- 25 minutes). This was accompanied by a decrease of total plasma clearance of r-hirudin. The volume of distribution of r-hirudin was significantly decreased (275 +/- 112 mL/kg versus 35 +/- 3 mL/kg), indicating that r-hirudin bound by AHAb is mainly distributed to the intravascular compartment. Taken together, both the half-life prolongation and the decrease of the volume of distribution contribute to r-hirudin accumulation and may explain respective findings in patients. In summary, two different effects of AHAbs seem to be clinically relevant: decreasing anticoagulant activity of r-hirudin by neutralization and accumulation of r-hirudin by reducing renal clearance. Formation of AHAbs has not yet been correlated with enhanced major bleeding complications. However, close monitoring of coagulation parameters is recommended in AHAb-positive patients during r-hirudin treatment.

Characterization of a Na(+)-Ca(2+) exchanger in podocytes.

BACKGROUND: Knowledge about Ca(2+) extrusion mechanisms in podocytes is limited. The aim of the study was to test whether a Na(+)-Ca(2+) exchanger (NCX) is present in differentiated podocytes and if so to examine its regulatory properties. METHODS: Intracellular Ca(2+) concentration ([Ca(2+)](i)) and intracellular pH were measured microspectrofluorometrically in single podocytes. Expression of NCX mRNA was studied by reverse transcription-polymerase chain reaction. NCX protein expression was investigated by immunocytochemistry. RESULTS: Substitution of extracellular Na(+) (from 145 to 0, 5, 10, 20, and 30 mM) with N-methyl-D-glucamine resulted in a Na(+) concentration-dependent, reversible increase of [Ca(2+)](i). Complete extracellular Na(+) substitution (0 Na(+)) increased [Ca(2+)](i) reversibly from 95+/-5 to 275+/-16 and back to 66+/-5 nM (n=205). Raising the intracellular Na(+) concentration by application of 50 micro M monensin increased [Ca(2+)](i) from 105+/-22 to 192+/-45 nM (n=12). The [Ca(2+)](i) response induced by a low Na(+) concentration required extracellular Ca(2+) and did not correlate with changes of intracellular pH. The effect was blocked by the NCX inhibitor benzamil (IC(50) approximately 100 nM). Neither flufenamate (100 micro M, n=6), a blocker of non-selective cation channels, nor Hoe 694 (1 micro M, n=6), an inhibitor of the Na(+)-H(+) exchanger, did significantly influence the [Ca(2+)](i) response induced by extracellular Na(+) depletion. Activation of protein kinase C (PKC) by short-term application (5 min) of phorbol 12-myristate-13-acetate (PMA; 10 nM, n=4; 100 nM, n=7) inhibited Na(+)-Ca(2+) exchange, whereas PKC inhibition by long-term incubation (24 h) with PMA (100 nM, n=9) or bisindolylmaleimide I (100 nM, n=11) both increased Na(+)-Ca(2+) exchange, respectively. Expression of NCX mRNA was detected both in cultured differentiated podocytes and in podocytes directly pulled off from glomeruli ex vivo. NCX protein expression was detected by immunocytochemistry. In a different series of experiments, we studied the potential involvement of the exchanger in podocyte injury induced by the aminonucleoside puromycin. Pre-treatment of podocytes with 0.3 mM puromycin for 24 h significantly reduced the [Ca(2+)](i) response induced by extracellular Na(+) depletion (n=56). Compared with mRNA expression of the housekeeping gene GAPDH, NCX mRNA expression was significantly reduced by puromycin. CONCLUSION: Our results demonstrate the presence of a Na(+)-Ca(2+) exchanger in podocytes and its regulation by PKC. Inhibition of Na(+)-Ca(2+) exchange by puromycin may contribute to podocyte injury in PAN nephrosis.