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Hermann Haller

Publications and source records attributed to Hermann Haller.

At least 19 recordsLinked to original sources
PubMed2007

Engulfment of apoptotic cells by microvascular endothelial cells induces proinflammatory responses.

Circulating endothelial cells (CECs) have been detected in a variety of vascular disorders, but their interactions with healthy endothelium remain unknown. The aim of this study was to evaluate the response of human endothelial cells (ECs) to apoptotic or necrotic ECs in an in vitro model and to delineate pathogenetic pathways. Here we show that incubation of the human microvascular endothelial cell line (HMEC-1) with apoptotic ECs resulted in increased expression of chemokines and enhanced binding of leukocytes to HMEC-1 cells, whereas exposure of HMEC-1 cells to necrotic ECs caused no changes in leukocyte-binding affinity. Both apoptotic and necrotic cells were bound and engulfed by HMEC-1 cells and primary human umbilical vein endothelial cells (HUVECs). We therefore suggest that exposures to apoptotic and necrotic ECs induce different patterns of chemokine synthesis and leukocyte adhesion in healthy ECs. These data indicate that CECs are not only markers of vascular damage but may induce proinflammatory signals in the endothelium.

Apoptosis↗
PubMed2007

p38 mitogen-activated protein kinase inhibition ameliorates angiotensin II-induced target organ damage.

We investigated whether or not p38 mitogen-activated protein kinase inhibition ameliorates angiotensin II-induced target organ damage. We used double transgenic rats harboring both human renin and angiotensinogen genes (dTGRs). dTGR, with or without p38 inhibitor (BIRB796; 30 mg/kg per day in the diet), and nontransgenic Sprague-Dawley rats were studied in 2 protocols. In protocol 1 (week 7), systolic blood pressure of untreated dTGRs was 204+/-4 mm Hg, but partially reduced after BIRB796 treatment (166+/-7 mm Hg), whereas Sprague-Dawley rats were normotensive. The cardiac hypertrophy index was unchanged in untreated and BIRB796-treated dTGRs. The beta-myosin heavy chain expression of BIRB796-treated hearts was significantly lower in BIRB796 compared with dTGRs, indicating a delayed switch to the fetal isoform. BIRB796 treatment significantly reduced cardiac fibrosis, connective tissue growth factor, tumor necrosis factor-alpha, interleukin-6, and macrophage infiltration. Albuminuria was not reduced in BIRB796-treated dTGRs. Tubular and glomerular damage with tumor necrosis factor-alpha expression was unaltered, although serum creatinine and cystatin C were normalized. Renal macrophage infiltration, fibrosis, and vessel damage were reduced. In protocol 2 (week 8), we focused on mortality and arrhythmogenic electrical remodeling. Mortality of untreated dTGRs was 100% but was reduced to 10% in the BIRB796 group. Cardiac magnetic field mapping showed prolongation of depolarization and repolarization in untreated dTGRs compared with Sprague-Dawley rats with a partial reduction by BIRB796. Programmed electrical stimulation elicited ventricular tachycardias in 81% of untreated dTGRs but only in 48% of BIRB796-treated dTGRs. In conclusion, BIRB796 improved survival, target organ damage, and arrhythmogenic potential in angiotensin II-induced target organ damage.

Angiotensin II↗
PubMed2007

CD2AP/CIN85 balance determines receptor tyrosine kinase signaling response in podocytes.

Defects in podocyte signaling are the basis of many inherited glomerular diseases leading to glomerulosclerosis. CD2-associated protein (CD2AP) is highly expressed in podocytes and is considered to play an important role in the maintenance of the glomerular slit diaphragm. Mice deficient for CD2AP (CD2AP(-/-)) appear normal at birth but develop a rapid onset nephrotic syndrome at 3 weeks of age. We demonstrate that impaired intracellular signaling with subsequent podocyte damage is the reason for this delayed podocyte injury in CD2AP(-/-) mice. We document that CD2AP deficiency in podocytes leads to diminished signal initiation and termination of signaling pathways mediated by receptor tyrosine kinases (RTKs). In addition, we demonstrate that CIN85, a paralog of CD2AP, is involved in termination of RTK signaling in podocytes. CIN85 protein expression is increased in CD2AP(-/-) podocytes in vitro. Stimulation of CD2AP(-/-) podocytes with various growth factors, including insulin-like growth factor 1, vascular endothelial growth factor, and fibroblast growth factor, resulted in a significantly decreased phosphatidylinositol 3-kinase/AKT and ERK signaling response. Moreover, increased CIN85 protein is detectable in podocytes in diseased CD2AP(-/-) mice, leading to decreased base-line activation of ERK and decreased phosphorylation after growth factor stimulation in vivo. Because repression of CIN85 protein leads to a restored RTK signaling response, our results support an important role of CD2AP/CIN85 protein balance in the normal signaling response of podocytes.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Decreased renal transplant function after parathyroidectomy.

BACKGROUND: Persistent secondary hyperparathyroidism after renal transplantation may require parathyroidectomy (PTX). Clinical experience suggests that these patients commonly develop decreased renal function thereafter. METHODS: To test this notion, we evaluated 76 transplant patients who underwent pararhyroidectomy between 1997 and 2003. RESULTS: In half the patients (47%), creatinine clearance decreased >20% (before vs after PTX, 57 +/- 21 vs 38 +/- 17 ml/min, P = 0.001). The patients with decreased creatinine clearance had higher parathyroid hormone (PTH) concentrations before and lower values after PTX compared with those who did not (594 +/- 392 vs 447 +/- 234 pg/ml before PTX, P = 0.03; 35 vs 123 pg/ml thereafter, P = 0.002). They also had lower serum calcium concentrations after PTX (2.0 vs 2.2 mmol/l, P = 0.005) and they required more calcium and vitamin D analogues. These patients also more commonly underwent total PTX with autotransplantation, compared with subtotal (75 vs 50%, P = 0.03). However, in multivariate analysis, only the delta PTH decline (%) after PTX was a significant predictor of deteriorating renal function (P = 0.005) and was correlated with the creatinine clearance decrease (R = 0.369, P = 0.001). Prospectively measured inulin and para-amino-hippuric acid (PAH) clearance decreased significantly after PTX in a subgroup of 19 patients (inulin before vs after PTX 67 vs 55 ml/min/1.73 m(2), P = 0.001; PAH 360 vs 289 ml/min/1.73 m(2), P = 0.001). Transplant biopsies revealed calcification in 70% of biopsied cases. CONCLUSION: Since PTH has a known positive regulatory effect on renal perfusion and glomerular filtration rate, we conclude that relative hypoparathyroidism after PTX is the main mechanism contributing to decreased renal function in these patients. There was no difference in 10-year-graft survival between the deteriorating and the non-deteriorating group.

Biopsy↗
PubMed2006

EPO: renoprotection beyond anemia correction.

Until recently the major physiological function of erythropoietin (EPO) was thought to be the induction of erythropoiesis. However, a growing body of evidence indicates that EPO has tissue-protective properties and prevents ischemia induced tissue damage in several organs including the kidney. A pivotal intracellular pathway mediating the beneficial effects of EPO is the activation of Akt, i.e. serine/threonine protein kinase B. As a result, Akt phosphorylates the proapoptotic factor Bad, which in turn causes inhibition of programmed cell death (apoptosis). In the present article we review data on the non-hematological effects of recombinant human EPO (rHuEPO) in different experimental settings of acute and chronic kidney injury, and discuss clinical renoprotective strategies with rHuEPO or analogues substances that are not related to anemia correction.

Anemia↗
PubMed2006

CCL19-IgG prevents allograft rejection by impairment of immune cell trafficking.

An adaptive immune response is initiated in the T cell area of secondary lymphoid organs, where antigen-presenting dendritic cells may induce proliferation and differentiation in co-localized T cells after T cell receptor engagement. The chemokines CCL19 and CCL21 and their receptor CCR7 are essential in establishing dendritic cell and T cell recruitment and co-localization within this unique microenvironment. It is shown that systemic application of a fusion protein that consists of CCL19 fused to the Fc part of human IgG1 induces effects similar to the phenotype of CCR7-/- animals, like disturbed accumulation of T cells and dendritic cells in secondary lymphoid organs. CCL19-IgG further inhibited their co-localization, which resulted in a marked inhibition of antigen-specific T cell proliferation. The immunosuppressive potency of CCL19-IgG was tested in vivo using murine models for TH1-mediated immune responses (delayed-type hypersensitivity) and for transplantation of different solid organs. In allogeneic kidney transplantation as well as heterotopic allogeneic heart transplantation in different strain combinations, allograft rejection was reduced and organ survival was significantly prolonged by treatment with CCL19-IgG compared with controls. This shows that in contrast to only limited prolongation of graft survival in CCR7 knockout models, the therapeutic application of a CCR7 ligand in a wild-type environment provides a benefit in terms of immunosuppression.

Animals↗
PubMed2006

IGF-binding protein-3 modulates TGF-beta/BMP-signaling in glomerular podocytes.

Podocyte apoptosis initiates progressive glomerulosclerosis in TGF-beta1 transgenic and CD2AP-knockout (CD2AP-/-) mice. It was previously shown that in both mouse models, activation of the TGF-beta pathway is the key event during development of podocyte apoptosis. Furthermore, CD2AP is an important modifier of TGF-beta-induced survival signaling via activation of the phosphoinositol 3-kinase/AKT signaling pathway. This article presents IGF-binding protein-3 (IGFBP-3) as a new modulator of apoptosis and survival signaling in glomerular podocytes. High expression of IGFBP-3 protein in the urine of diseased CD2AP-/- mice was discovered, and IGFBP-3 expression in glomerular podocytes and parietal cells was detected. IGFBP-3 can induce changes in podocyte actin cytoskeleton, leads to apoptosis in cultured murine podocytes, and can enhance TGF-beta1-induced apoptosis in vitro. For studying this process on a molecular level, proapoptotic p38 mitogen-activated protein kinase pathways and antiapoptotic phosphoinositol 3-kinase/AKT pathways were examined in cultured murine podocytes. It was found that IGFBP-3 increments the level of TGF-beta1-induced phosphorylated p38 mitogen-activated protein kinase and decreases the phosphorylation of antiapoptotic AKT. This effect is specific for the co-stimulation of IGFBP-3 with TGF-beta1 because a combination of IGFBP-3 with bone morphogenic protein-7 (BMP-7), another member of the TGF-beta superfamily, results in apoptosis opposing signaling effects with a strong increase of phosphorylated AKT and subsequent functional effects. These results demonstrate that the IGF/IGFBP axis plays an important role in the development of podocyte apoptosis by modulation of TGF-beta and BMP-7-induced pro- and antiapoptotic signals.

Adolescent↗
PubMed2006

Cellular and molecular mechanisms of tissue protection by lipophilic calcium channel blockers.

Long-acting third-generation dihydropyridine calcium channel blockers (CCBs) improve endothelial dysfunction and prevent cardiovascular events in humans, but their cellular and molecular mechanisms of tissue protection are not elucidated in detail. We assessed organ (renal) protection by the highly lipophilic CCB lercanidipine in a double-transgenic rat (dTGR) model with overexpression of human renin and angiotensinogen genes. We randomly treated dTGR with lercanidipine (2.5 mg/kg/day; n=20) or vehicle (n=20) for 3 wk. Furthermore, we explored the influence of lercanidipine on protein kinase C (PKC) signaling in vivo and in vitro using endothelial and vascular smooth muscle cell cultures. Cumulative mortality was 60% in untreated dTGR, whereas none of the lercanidipine-treated animals died (P<0.001). We found significantly less albuminuria and improved renal function in lercanidipine-treated dTGR (both P<0.05). Lercanidipine treatment also significantly (P<0.05) reduced blood levels of the endogenous NOS inhibitor asymmetric dimethylarginine. On histological examination, we observed significantly less tissue inflammation and fibrosis in lercanidipine-treated animals (both P<0.05). Lercanidipine significantly inhibited angiotensin (ANG) I-mediated PKC-alpha and -delta activation in vivo and in vitro, partly due to reduced intracellular calcium flux. As a result, lercanidipine improved endothelial cell permeability in vitro. Lercanidipine prevents tissue injury and improves survival in a model of progressive organ damage. These effects may result, at least in part, from inhibition of tissue inflammation as well as improved NO bioavailability. Modulation of PKC activity may be an important underlying intracellular mechanism.

Albumins↗
PubMed2006

Removal selectivity of Prometheus: a new extracorporeal liver support device.

AIM: To evaluate whether treatment with the Prometheus reg system significantly affects cytokines, coagulation factors and other plasma proteins. METHODS: We studied nine patients with acute-on-chronic liver failure and accompanying renal failure. Prometheus reg therapy was performed on 2 consecutive days for up to 6 h in all patients. Several biochemical parameters and blood counts were assessed at regular time points during Prometheus reg treatment. RESULTS: We observed a significant decrease of both protein-bound (e.g. bile acids) and water-soluble (e.g. ammonia) substances after Prometheus reg therapy. Even though leukocytes increased during treatment (P<0.01), we found no significant changes of C-reactive protein, interleukin-6, and tumor necrosis factor-alpha plasma levels (all P>0.5). Further, antithrombin 3, factor II and factor V plasma levels did not decrease during Prometheus reg therapy (all P>0.5), and the INR remained unchanged (P=0.4). Plasma levels of total protein, albumin, and fibrinogen were also not altered during Prometheus reg treatment (all P>0.5). Finally, platelet count did not change significantly during therapy (P=0.6). CONCLUSION: Despite significant removal of protein-bound and water-soluble substances, Prometheus reg therapy did not affect the level of cytokines, coagulation factors or other plasma proteins. Thus, the filters and adsorbers used in the system are highly effective and specific for water-soluble substances and toxins bound to the albumin fraction.

Blood Coagulation Factors↗
PubMed2006

[Kidney and hypertension].

The regulation of blood pressure is a complex process, involving several organs. The kidney plays a major role and is involved in the initiation and maintenance of hypertension. Mechanisms involved are: (1) the sympathetic nerveous system, (2) the renin-angiotensin system, (3) the regulation of sodium and water balance, (4) the production of vasoactive substances such as endothelin, adenosine or nitric oxide (NO), and (5) structural alterations such as a reduced number of glomeruli and nephrons. Several therapeutic intervention strategies affecting these mechanisms have already proven to be effective antihypertensive drugs.

Adult↗
PubMed2006

Agonistic antibodies directed at the angiotensin II, AT1 receptor in preeclampsia.

Immune mechanisms and circulating mediators may be important in the pathogenesis of preeclampsia. We review our findings on agonistic antibodies against the angiotensin II (Ang II) receptor (AT1-AA) and their possible role in the pathogenesis of this disorder. AT1-AA appear in the course of preeclampsia and are largely gone by 6 weeks after delivery. AT1-AA detection relies on a bioassay using spontaneously beating neonatal rat cardiomyocytes. Their specificity has been documented by other methods, including Western blotting, co-localization, and co-immunoprecipitation experiments. AT1-AA induce signaling in vascular cells and trophoblasts including transcription factor activation. The signaling results in tissue factor production and reactive oxygen species generation, both of which have been implicated in preeclampsia. The role of AT1-AA in preeclampsia and other severe hypertensive conditions has not yet been proved with certainty. However, we believe the findings are compelling and warrant further study.

Angiotensin II↗
PubMed2006

Mechanisms of disease: erythropoietin--an old hormone with a new mission?

The major physiological function of erythropoietin is the induction of erythropoiesis. A growing body of evidence indicates, however, that this hormone has tissue-protective effects and prevents tissue damage during ischemia and inflammation. This review article summarizes the present knowledge on the cardiovascular and renal protective effects of erythropoietin and discusses the possible underlying mechanisms.

Anemia↗
PubMed2006

Circulating endothelial cells as a prognostic marker in thrombotic microangiopathy.

BACKGROUND: Circulating endothelial cells (CECs) are a reliable marker of disease activity in a variety of vascular disorders. Damage to microvascular endothelial cells is a hallmark of thrombotic microangiopathy (TMA). The aim of this study is to identify and count CECs during the course of TMA and evaluate whether cell numbers may serve as a prognostic marker in patients undergoing plasma exchange. METHODS: Fifteen patients (8 women, 7 men) aged 31 to 66 years with TMA of different causes were studied before and after 4 sessions of plasma exchange. CECs were isolated by using anti-CD146-driven immunomagnetic isolation and counted after staining with Ulex Europaeus lectin-1. RESULTS: Numbers of CECs were markedly elevated in all patients before treatment (64 to 672 CEC/mL; mean, 320 +/- 205 CEC/mL) compared with healthy controls (0 to 16 CEC/mL; mean, 6.4 +/- 4.2 CEC/mL; P < 0.001). Patients with a favorable outcome had significantly greater initial CEC levels (mean, 426 +/- 175 CEC/mL; P < 0.001), and cell numbers decreased significantly after 4 treatments of plasma exchange (mean, 101 +/- 53 CEC/mL; P = 0.001). Patients with disease unresponsive to plasma exchange presented with lower initial CEC levels (mean, 108 +/- 36 CEC/mL), and numbers failed to decrease after plasma exchange (mean, 114 +/- 57 CEC/mL; P = 0.827). CONCLUSION: Markedly elevated numbers of CECs reflect severe and widespread endothelial damage in patients with TMA. Cell numbers at presentation and their degree of decrease after 4 sessions of plasma exchange could provide important prognostic clues.

Adult↗
PubMed2006

Treatment of severe refractory pruritus with fractionated plasma separation and adsorption (Prometheus).

OBJECTIVE: Severe pruritus is a serious complication of cholestatic liver disease. Prometheus is a recently introduced extracorporeal liver support system with direct toxin adsorption of the patient's albumin fraction (FPSA; fractionated plasma separation and adsorption). Here we report on the effect of Prometheus therapy in patients with intractable cholestatic pruritus. MATERIAL AND METHODS: Seven patients with different liver diseases and severe pruritus refractory to all medical treatment efforts for more than 4 weeks were treated with Prometheus (3-5 times, 18+/-3 h total). Pruritus intensity was assessed using the visual analogue scale (VAS; from 0 = no pruritus to 10 = unbearable pruritus), and VAS, serum bile acids and total bilirubin were evaluated directly before and after Prometheus treatment, as well as 4 weeks later. RESULTS: After Prometheus therapy, VAS values had dropped significantly from 9+/-1 to 3+/-3 (p<0.001). Likewise, serum bile acids decreased (from 248+/-192 to 101+/-85 micromol/l; p<0.03). All patients, with the exception of one with no initial bile acid elevation, reported a pronounced improvement in pruritus with Prometheus therapy, although in two anicteric patients the amelioration lasted only a few days. In the other four patients a distinct benefit was still observed 4 weeks after the treatment. CONCLUSIONS: Prometheus therapy significantly improved refractory pruritus in all patients with elevated bile acid levels, but in some patients the clinical benefit was of short duration. The clinical findings suggest that we have to better characterize those patients who might derive a long-lasting benefit from this invasive and expensive treatment.

Adsorption↗
PubMed2006

Efficacy and safety of lercanidipine versus hydrochlorothiazide as add-on to enalapril in diabetic populations with uncontrolled hypertension.

OBJECTIVE: Angiotensin-converting enzyme inhibitors plus dihydropyridine calcium channel blockers or low-dose thiazide diuretics are considered first-line therapies in hypertensive diabetic patients as glucose metabolism is not relevantly affected. Most diabetic patients require at least two different drug classes to achieve the recommended target blood pressure of 130/85 mmHg. This controlled clinical trial investigated the calcium channel blocker lercanidipine versus hydrochlorothiazide (HCTZ) as add-on in diabetic patients with uncontrolled hypertension on enalapril monotherapy. METHODS: Overall, 174 patients (18-80 years old, well-controlled diabetes type 1 or 2, mild to moderate hypertension) were included in a 2-week placebo run-in followed by 4 weeks on enalapril 20 mg. Subsequently, 135 non-responders (90 mmHg < or = mean sitting diastolic blood pressure < or = 109 mmHg) were randomized to 20 weeks of double-blind add-on therapy to enalapril with either lercanidipine 10 mg (n = 69) or HCTZ 12.5 mg (n = 66). The primary study objective was to prove non-inferiority of lercanidipine add-on versus HCTZ add-on in reducing sitting diastolic blood pressure; response rates and tolerability data were also observed. RESULTS: Both add-on treatments clearly decreased diastolic blood pressure to a greater extent than enalapril monotherapy (mean +/- SD changes at study end: lercanidipine, -9.3 mmHg; HCTZ, -7.4 mmHg); non-inferiority of lercanidipine versus HCTZ was formally proven. Blood pressure response rates reached 69.6% on enalapril plus lercanidipine as compared with 53.6% on enalapril plus HCTZ (difference between treatments, P > 0.05). Blood pressure of 130/85 mmHg or less was achieved in 30.4% of patients on lercanidipine add-on and in 23.2% of those randomized to HCTZ add-on (P > 0.05). Both treatment regimens were well tolerated. CONCLUSION: Lercanidipine add-on showed comparable efficacy to HCTZ add-on in diabetic patients with hypertension badly controlled on angiotensin-converting enzyme inhibitor monotherapy. The blood pressure response rates seemed to be somewhat higher following enalapril plus lercanidipine than enalapril plus HCTZ.

Adolescent↗
PubMed2006

Preventing microalbuminuria in patients with diabetes: rationale and design of the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) study.

Diabetic nephropathy has developed into a worldwide epidemic and is responsible for the majority of end-stage renal disease in most countries. Antihypertensive treatment slows the progression of the disease. In addition, blockade of the renin-angiotensin system reduces the degree of albuminuria and angiotensin II receptor blockers (ARBs) have been shown to delay the progression from microalbuminuria to overt proteinuria in patients with diabetes. However, few studies have examined whether the initial stage of diabetic nephropathy (i.e. the development of microalbuminuria) in patients with type 2 diabetes can be slowed or prevented by ARB treatment. The Randomised Olmesartan And Diabetes MicroAlbuminuria Prevention (ROADMAP) study is a placebo-controlled, multicentre, double-blind, parallel group study investigating the effect of the ARB, olmesartan medoxomil, on the incidence of microalbuminuria. A total of 4400 type 2 diabetes patients with normoalbuminuria will be randomized to treatment with 40 mg of olmesartan medoxomil once daily or placebo. Goal blood pressure will be 130/80 mmHg. The primary endpoint of the study is the occurrence of microalbuminuria. In ROADMAP, we will also assess as secondary endpoints the effects of olmesartan on fatal and non-fatal cardiovascular events in patients with diabetes. In addition, within subgroups of the ROADMAP patients, the effects of olmesartan on retinopathy and other microvascular circulations will be analysed. The study is expected to last a median of 5 years. The ROADMAP study will answer the question whether an ARB can prevent or delay the onset of microalbuminuria and whether this translates into protection against cardiovascular events and renal disease.

Adolescent↗