Interventional treatment of para-valvular leaks after prosthetic valve replacement with plug devices -first results from a prospective registry

Background

Interventional closure of symptomatic paravalvular leaks (PVL) after surgical or interventional valve replacement by plug implantation has emerged as an alternative to surgical correction, which is associated with high morbitity and mortality rates. To date, data on procedural efficacy and clinical outcome after transcatheter closure with plugs is sparse, especially prospective data are missing.

Methods

We analysed data from a multi-center prospective registry on interventional PVL closure with plug devices.

Results

Between 06/2012 and 04/2020 55 interventions were performed with different numbers of plugs (maximal 4) in 51 patients at 9 hospitals. Interventions were performed in 15 women and 36 men at high surgical risk for repeat surgery. 48% of procedures were performed for mitral PVLs and 52% procedures were performed for aortic PVLs. Mean age of the population treated was 69±13 years and mean log. Euro-Score I was 22.5±14.2%. Patients were treated by implantation of Amplatzer Vascular Plug III (80%) and Occlutec occluders (9%). Aortic PVLs were treated using a retrograde transfemoral access, mitral PVLs were treated using either a transseptal (25/26) or transapical access (1/26) with 3-dimensional transesophageal echocardiographic and fluoroscopic guidance. Indication for PVL closure was previous surgery (n=39), high-risk patients (n=24), heart failure (n=22), age (n=20) and hemolysis (n=12). 40 patients had NYHA class III/IV at admission. Interventional closure of PVL was completely successful in 40 procedures (73%), partially successful in 7 procedures (13%) and failed in 7 procedures (13%). NYHA class I/II after PVL closure was achieved in 75% patients. However, 8 out of 12 patients with hemolysis as indication still hemolyzed at discharge. Complications occurred in 16% of patients. In-hospital mortality rate was 4% of procedures (2/51). After hospital discharge no death occurred during 30-day follow-up.

Conclusions

In this prospective interventional PVL registry inclusion rate was lower than expected. There was an equal distribution of aortal and mitral PVLs. At least partial success could be achieved in 86% of patients, with significant functional improvement in most patients. In this high risk population hospital mortaliy was low (4%), indicating that interventional PVL treatment should be the treatment of choice, when discussed by a heart team.

Funding Acknowledgement

Type of funding sources: None.

Rat Model of Widespread Cerebral Cortical Demyelination Induced by an Intracerebral Injection of Pro-Inflammatory Cytokines

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system (CNS) and progressively leads to physical disability and death, caused by white matter lesions in the spinal cord and cerebellum, as well as by demyelination in grey matter. Whilst conventional models of experimental allergic encephalomyelitis are suitable for the investigation of the cell-mediated inflammation in the spinal and cerebellar white matter, they fail to address grey matter pathologies. Here, we present the experimental protocol for a novel rat model of cortical demyelination allowing the investigation of the pathological and molecular mechanisms leading to cortical lesions. The demyelination is induced by an immunization with low-dose myelin oligodendrocyte glycoprotein (MOG) in an incomplete Freund's adjuvant followed by a catheter-mediated intracerebral delivery of pro-inflammatory cytokines. The catheter, moreover, enables multiple rounds of demyelination without causing injection-induced trauma, as well as the intracerebral delivery of potential therapeutic drugs undergoing a preclinical investigation. The method is also ethically favorable as animal pain and distress or disability are controlled and relatively minimal. The expected timeframe for the implementation of the entire protocol is around 8 - 10 weeks.

4291Six-month outcomes from the multicenter, prospective study with the novel PASCAL transcatheter valve repair system for patients with mitral regurgitation in the CLASP study

Background

Severe mitral regurgitation may lead to an impaired prognosis if left untreated. Transcatheter treatment options have emerged as an alternative to surgery and an adjunct to medical therapy. We report the six-month results of the PASCAL transcatheter valve repair system in treating patients with mitral regurgitation enrolled in the multicenter, prospective, single arm CLASP study.

Methods

The PASCAL Transcatheter Valve Repair System is a leaflet repair therapy that uses clasps and paddles to place a woven Nitinol spacer between the native valve leaflets to fill the regurgitant orifice via a transseptal approach. Eligible patients had clinically significant MR despite optimal medical therapy and were deemed candidates for transcatheter mitral repair by the local Heart Team. Safety, performance, and clinical outcomes were prospectively assessed at baseline, discharge, 30 days, and 6 months post-procedure. All major adverse events (MAE) were adjudicated by an independent clinical events committee and echocardiographic images were assessed by a core lab. The MAE rate was the primary safety endpoint, defined as the composite of cardiovascular mortality, stroke, MI, new need for renal replacement therapy, severe bleeding, and re-intervention for study device-related complications.

Results

Between June 2017 and September 2018, 62 patients were enrolled at 14 sites worldwide for transcatheter mitral valve reconstruction using the PASCAL system. The mean age was 76.5 years (62.9% male). All patients had MR grade ≥3+, with 59% functional, 34% degenerative, and 7% mixed etiology, and 51.6% of patients were in NYHA Class III/IV. Successful implantation of the PASCAL device was achieved in 95% of patients. At discharge, 95% of patients had MR grade ≤2+ with 81% grade ≤1+. There was one cardiovascular mortality and the MAE rate was 4.8%. At 30-day follow-up, paired analyses shows that 98% of patients had MR grade ≤2+ with 81% grade ≤1+ and 88% were in NYHA Class I/II (p<0.0001). The 6MWD improved by 38.9 m (p=0.0015) and was accompanied by average improvements in KCCQ and EQ5D scores by 14.1 points (p<0.0001) and 8.3 points (p=0.0028), respectively. The six-month data will be available for presentation.

Conclusions

In this early device experience, the PASCAL transcatheter valve repair system showed an acceptable safety profile and performed as intended in treating patients with mitral regurgitation. The PASCAL device resulted in significant MR grade reduction, which was associated with clinically and statistically significant improvements in functional status, exercise capacity, and quality of life. Continued follow-up is warranted to validate these initial promising results.

Acknowledgement/Funding

Edwards Lifesciences

P4716One-year outcomes of the tri-repair study assessing cardioband tricuspid valve reconstruction system for patients with severe tricuspid regurgitation

Background

Severe tricuspid regurgitation (TR) is associated with high morbidity and mortality rates with limited treatment options.

Objectives

We report the one-year outcomes of the Cardioband™ Tricuspid Valve Reconstruction System in the treatment of severe functional TR in 30 patients enrolled in the TRI-REPAIR study.

Methods

Between October 2016 and July 2017, 30 patients were enrolled in this single-arm, multicenter, prospective study. Patients were diagnosed with severe, symptomatic TR in the absence of untreated left-heart disease and deemed inoperable because of unacceptable risk for open-heart surgery by the local heart team. Clinical, functional, and echocardiographic data were prospectively collected before and up to one year post-procedure. An independent core lab assessed all echocardiographic data and an independent clinical event committee adjudicated the safety events.

Results

Mean patient age was 75 years, 73% were females, 23% had ischemic heart disease, and 93% had atrial fibrillation. At baseline, 83% were in NYHA Class III-IV, 63% had edema, and LVEF was 58%. Technical success was 100%. Through one year, one patient had a reintervention and exited the study. Five patients died of which one was device-related. Between baseline and one year (paired analyses), echocardiography showed average reductions of annular septolateral diameter of 16% (44mm vs. 37mm; p<0.0001), PISA EROA of 49% (0.73cm2 vs. 0.37cm2, p=0.0037), and mean vena contracta of 30% (1.2cm vs. 0.9cm, p=0.0046). Clinical assessment showed that at one year 78% of patients were in NYHA Class I-II (p=0.0003). Six minute walk distance improved by 42m (p=0.0525). Kansas City Cardiomyopathy Questionnaire score improved by 19 points (p=0.0009). Edema was absent in 70% of the patients.

Conclusions

These results show that the Cardioband tricuspid system performs as intended and appears to be safe in patients with symptomatic and severe functional TR. At one year significant reduction of TR through a sustained decrease of annular dimensions, improvements in heart failure symptoms, quality of life, and exercise capacity were observed. Further studies are warranted to validate these initial promising results.

Acknowledgement/Funding

Edwards Lifescieinces

P3858High H2FPEF score is an independent predictor of adverse outcome in patients with severe aortic stenosis and preserved ejection fraction undergoing TAVR

Background

Recently, the H2FPEF score has been developed in an evidence-based approach relying on simple clinical and echocardiographic variables. It enables the identification of patients with high probability of prevalent heart failure with preserved ejection fraction (HFpEF) which is associated with a dismal prognosis. Left ventricular diastolic dysfunction, a key mechanism in HFpEF, is also a common finding in patients with severe aortic stenosis.

Objective

To assess the prognostic impact of the H2FPEF score in patients with preserved ejection fraction and severe aortic stenosis undergoing Transcatheter Aortic Valve Replacement (TAVR).

Methods

Among 1148 patients with preserved ejection fraction who received TAVR at our institution between 2013 and 2018, data for calculation of the H2FPEF score was available in 535 patients. Score variables include BMI >30 kg/m2, arterial hypertension, atrial fibrillation, pulmonary hypertension >35 mmHg, age >60 years, and elevated LV filling pressure. Patients were dichotomized according to “low” (1–5 points; n=377) and “high” H2FPEF scores (6–9; n=158). Kaplan-Meier survival curves and Cox regression analyses were used to assess the prognostic impact of H2FPEF scores. Median follow-up time was 0.3 years.

Results

TAVR patients presenting with high H2FPEF scores had higher prevalence of moderate to severe mitral regurgitation (19.4% vs. 33.6%, p<0.001) as well as tricuspid regurgitation (15.2% vs. 35.1%, p<0.001), and presented with lower stroke volume index (42.2 ml/m2 vs. 36.0 ml/m2, p<0.001) compared to those with low H2FPEF scores. All-cause mortality one year after TAVR was significantly higher in patients in the high H2FPEF score group (10.5% vs. 21.0%, p=0.0019, Figure 1). Multivariate analysis revealed a high H2FPEF score to be independently predictive for 1-year all-cause mortality (HR 2.66, 95% CI: 1.41–5.02, p=0.025). Among the single H2FPEF score variables, atrial fibrillation (HR 3.45, 95% CI: 1.86–6.40, p<0.001) and systolic pulmonary hypertension >55 mmHg (HR=2.68, 95% CI: 0.97–7.40, p=0.057) were strong independent predictors of adverse outcome.

Figure 1. All-cause mortality of patients undergoing TAVR after one year stratified by low (1–5 points) and high (6–9) H2FPEF score

Conclusion

An elevated H2FPEF score of >6 is independently predictive for mortality in patients with preserved ejection fraction undergoing TAVR for severe aortic stenosis. Our findings provide evidence that the H2FPEF score, which was meant for diagnostic use originally, is able to serve as a prognostic tool in patients with preserved ejection fraction undergoing TAVR, highlighting the adverse impact of diastolic dysfunction in patients with preserved ejection fraction and aortic stenosis.

P1848Prevalence and outcomes in patients with Heyde syndrome after transcatheter aortic valve implantation, a single centre experience

Introduction

Heyde syndrome is known as the association of severe aortic stenosis (AS) and recurrent gastrointestinal bleeding (GIB) from angiodysplasia. To date only few data exist regarding the prevalence of Heyde syndrome and results after transcatheter aortic valve implantation (TAVI) for the treatment of AS.

Purpose

We sought to evaluate the prevalence of Heyde syndrome in a routine clinical cohort of patients undergoing TAVI and analyze the effectiveness of treatment of AS regarding recurrent GIB in these patients.

Methods

We conducted a retrospective single-center analysis of 2545 consecutive patients who underwent TAVI for the treatment of AS in 2008–2017. Patients with a history of GIB were identified. The diagnosis of Heyde syndrome was defined as a clinical triad of presence of severe AS, a history of recurrent GIB, and an endoscopic diagnosis of angiodysplasia. GIB of unknown origin or related to other causes was defined as bleeding unrelated to angiodysplasia. Clinical outcomes of patients with Heyde syndrome were evaluated with emphasis on bleeding complications and recurrence of GIB.

Results

A history of GIB prior to TAVI was detected in 190 patients (7.5%) of the TAVI cohort. Among them, 143 patients had a GIB unrelated to angiodysplasia (5.6%) and 47 patients (1.8%) were diagnosed with Heyde syndrome. Median age and STS-PROM were 80.7 (75.3, 84.0) years and 4.7 (2.7, 9.0) respectively in Heyde patients. TAVI was successfully performed in all cases (66% endovascular access, 34% transapical access). The effective orifice areas increased from 0.8±0.1 cm2 to 2.1±0.5 cm2. Periprocedural major/life-threatening bleeding was found in 6 patients (12.8%), mainly access-related and none due to GIB. In 51% of Heyde-patients transfusion of 4.5±5.7 packed red blood cells was required during the index hospitalisation. During a mean follow-up of 12 months, recurrent GIB after TAVI was detected in 32% of patients with Heyde syndrome. In contrast only 18% of patients with GIB unrelated to angiodysplasia (Non-Heyde) had recurrent GIB after TAVI. In patients diagnosed with Heyde syndrome and recurrent GIB after TAVI the rate of residual mild or moderate paravalvular regurgitation was higher compared to those with an unremarkable course (73% vs. 37%, p=0.045).

Figure 1. 1-year Follow-Up

Conclusions

A relevant number of patients presenting for treatment of AS can be diagnosed with Heyde syndrome. In these patients TAVI can be successfully performed with moderate incidence of periprocedural bleeding complications but significant transfusion rates. Regardless of successful treatment of AS, recurrent GIB was detected in a significant number of Heyde patients during follow-up. The possible association with residual paravalvular regurgitation requires further investigation to improve treatment options in patients with Heyde syndrome.

MicroRNA-451a overexpression induces accelerated neuronal differentiation of Ntera2/D1 cells and ablation affects neurogenesis in microRNA-451a-/- mice

MiR-451a is best known for its role in erythropoiesis and for its tumour suppressor features. Here we show a role for miR-451a in neuronal differentiation through analysis of endogenous and ectopically expressed or silenced miR-451a in Ntera2/D1 cells during neuronal differentiation. Furthermore, we compared neuronal differentiation in the dentate gyrus of hippocampus of miR-451a^-/- and wild type mice. MiR-451a overexpression in lentiviral transduced Ntera2/D1 cells was associated with a significant shifting of mRNA expression of the developmental markers Nestin, βIII Tubulin, NF200, DCX and MAP2 to earlier developmental time points, compared to control vector transduced cells. In line with this, accelerated neuronal network formation in AB.G.miR-451a transduced cells, as well as an increase in neurite outgrowth both in number and length was observed. MiR-451a targets genes MIF, AKT1, CAB39, YWHAZ, RAB14, TSC1, OSR1, POU3F2, TNS4, PSMB8, CXCL16, CDKN2D and IL6R were, moreover, either constantly downregulated or exhibited shifted expression profiles in AB.G.miR-451a transduced cells. Lentiviral knockdown of endogenous miR-451a expression in Ntera2/D1 cells resulted in decelerated differentiation. Endogenous miR-451a expression was upregulated during development in the hippocampus of wildtype mice. In situ hybridization revealed intensively stained single cells in the subgranular zone and the hilus of the dentate gyrus of wild type mice, while genetic ablation of miR-451a was observed to promote an imbalance between proliferation and neuronal differentiation in neurogenic brain regions, suggested by Ki67 and DCX staining. Taken together, these results provide strong support for a role of miR-451a in neuronal maturation processes in vitro and in vivo.

Effects of Corroded and Non-Corroded Biodegradable Mg and Mg Alloys on Viability, Morphology and Differentiation of MC3T3-E1 Cells Elicited by Direct Cell/Material Interaction

This study investigated the effect of biodegradable Mg and Mg alloys on selected properties of MC3T3-E1 cells elicited by direct cell/material interaction. The chemical composition and morphology of the surface of Mg and Mg based alloys (Mg2Ag and Mg10Gd) were analysed by scanning electron microscopy (SEM) and EDX, following corrosion in cell culture medium for 1, 2, 3 and 8 days. The most pronounced difference in surface morphology, namely crystal formation, was observed when Pure Mg and Mg2Ag were immersed in cell medium for 8 days, and was associated with an increase in atomic % of oxygen and a decrease of surface calcium and phosphorous. Crystal formation on the surface of Mg10Gd was, in contrast, negligible at all time points. Time-dependent changes in oxygen, calcium and phosphorous surface content were furthermore not observed for Mg10Gd. MC3T3-E1 cell viability was reduced by culture on the surfaces of corroded Mg, Mg2Ag and Mg10Gd in a corrosion time-independent manner. Cells did not survive when cultured on 3 day pre-corroded Pure Mg and Mg2Ag, indicating crystal formation to be particular detrimental in this regard. Cell viability was not affected when cells were cultured on non-corroded Mg and Mg alloys for up to 12 days. These results suggest that corrosion associated changes in surface morphology and chemical composition significantly hamper cell viability and, thus, that non-corroded surfaces are more conducive to cell survival. An analysis of the differentiation potential of MC3T3-E1 cells cultured on non-corroded samples based on measurement of Collagen I and Runx2 expression, revealed a down-regulation of these markers within the first 6 days following cell seeding on all samples, despite persistent survival and proliferation. Cells cultured on Mg10Gd, however, exhibited a pronounced upregulation of collagen I and Runx2 between days 8 and 12, indicating an enhancement of osteointegration by this alloy that could be valuable for in vivo orthopedic applications.

Multimodal MR imaging of acute and subacute experimental traumatic brain injury: Time course and correlation with cerebral energy metabolites

BACKGROUND

Traumatic brain injury (TBI) is one of the leading causes of death and permanent disability world-wide. The predominant cause of death after TBI is brain edema which can be quantified by non-invasive diffusion-weighted magnetic resonance imaging (DWI).

PURPOSE

To provide a better understanding of the early onset, time course, spatial development, and type of brain edema after TBI and to correlate MRI data and the cerebral energy state reflected by the metabolite adenosine triphosphate (ATP).

MATERIAL AND METHODS

The spontaneous development of lateral fluid percussion-induced TBI was investigated in the acute (6 h), subacute (48 h), and chronic (7 days) phase in rats by MRI of quantitative T2 and apparent diffusion coefficient (ADC) mapping as well as perfusion was combined with ATP-specific bioluminescence imaging and histology.

RESULTS

An induced TBI led to moderate to mild brain damages, reflected by transient, pronounced development of vasogenic edema and perfusion reduction. Heterogeneous ADC patterns indicated a parallel, but mixed expression of vasogenic and cytotoxic edema. Cortical ATP levels were reduced in the acute and subacute phase by 13% and 27%, respectively, but were completely normalized at 7 days after injury.

CONCLUSION

The partial ATP reduction was interpreted to be partially caused by a loss of neurons in parallel with transient dilution of the regional ATP concentration by pronounced vasogenic edema. The normalization of energy metabolism after 7 days was likely due to infiltrating glia and not to recovery. The MRI combined with metabolite measurement further improves the understanding and evaluation of brain damages after TBI.

Repetitive long-term hyperbaric oxygen treatment (HBOT) administered after experimental traumatic brain injury in rats induces significant remyelination and a recovery of sensorimotor function

Cells in the central nervous system rely almost exclusively on aerobic metabolism. Oxygen deprivation, such as injury-associated ischemia, results in detrimental apoptotic and necrotic cell loss. There is evidence that repetitive hyperbaric oxygen therapy (HBOT) improves outcomes in traumatic brain-injured patients. However, there are no experimental studies investigating the mechanism of repetitive long-term HBOT treatment-associated protective effects. We have therefore analysed the effect of long-term repetitive HBOT treatment on brain trauma-associated cerebral modulations using the lateral fluid percussion model for rats. Trauma-associated neurological impairment regressed significantly in the group of HBO-treated animals within three weeks post trauma. Evaluation of somatosensory-evoked potentials indicated a possible remyelination of neurons in the injured hemisphere following HBOT. This presumption was confirmed by a pronounced increase in myelin basic protein isoforms, PLP expression as well as an increase in myelin following three weeks of repetitive HBO treatment. Our results indicate that protective long-term HBOT effects following brain injury is mediated by a pronounced remyelination in the ipsilateral injured cortex as substantiated by the associated recovery of sensorimotor function.

Pharyngeal selective brain cooling is associated with reduced CNS cortical lesion after experimental traumatic brain injury in rats

Therapeutic hypothermia (TH) is still being explored as a therapeutic option after traumatic brain injury (TBI) but clinical data has not supported its efficacy. Experimental approaches were promising, but clinical data did not support its efficacy in the treatment of TBI. A novel approach of pharyngeal selective brain cooling (pSBC), recently introduced by our group, has been accompanied by superior neurofunctional, sensorimotor, and cognitive outcomes. This work is now extended by data on histomorphological and physical outcomes after pSBC in a model of experimental TBI. Male Sprague-Dawley rats were subjected to lateral fluid-percussion (LFP) brain injury, and randomized to the following experimental groups: (1) TBI with pSBC, (2) TBI without pSBC, and (3) sham animals. On day post-injury (DPI) 14, the animals were sacrificed and their brains were harvested for immunohistochemistry using the following antibodies: (1) glial fibrillary acidic protein (GFAP), (2) neurofilament (NF), and (3) synaptophysin (SY). In pSBC animals brain temperature was selectively lowered to 33 ± 0.5°C within 15 min post-injury, and maintained for 180 min after induction, while keeping rectal temperatures at physiological levels. Animals that had undergone pSBC showed a significantly faster recovery of body weight starting on DPI 3, and had gained substantially more weight than TBI-only animals on DPI 14 (p < 0.001), indicating superior physical recovery. Areas of cortical damage were significantly smaller in pSBC animals compared to TBI-only animals (p < 0.01). pSBC was associated with preservation of cortical tissue ipsilateral to the lesion, and superior physical recovery after experimental TBI. These results complement earlier reports in which pSBC was associated with superior neurofunctional and cognitive outcomes using the same experimental model.

Comparative study on the in vitro human skin permeation of monoterpenes and phenylpropanoids applied in rose oil and in form of neat single compounds

Essential oils are ingredients of cosmetic and health care products as well as massage oil used in aromatherapy. There is no doubt that essential oils and their components are able to permeate human skin. But information is rare dealing with percutanous absorption of essential oils in more detail. In this paper we investigated the in vitro skin permeation of monoterpenes and phenylpropanoids applied in pure rose oil and in form of neat single substances. We found that the application form had an exceeding influence on the skin permeation behaviour of the compounds. For substances applied in rose oil a clear relationship between their lipophilic character, chemical structure, and skin permeation could be confirmed. Regarding the P(app)-values the substances are ranked in the order: monoterpene hydrocarbons < monoterpene alcohols < monoterpene ketons < phenylpropanoids. In contrast, for neat single substances there were no relationships between their lipophilic characters, structures and skin permeation. Furthermore, except for alpha-pinene and isomenthone, the P(app)-values of all other substances were several times higher when applied in pure native rose oil than in their neat form. This suggests that co-operative interactions between essential oil components may promote skin permeation behaviour of essential oil and its components.

Pharyngeal selective brain cooling improves neurofunctional and neurocognitive outcome after fluid percussion brain injury in rats

Therapeutic hypothermia (TH) after cardiac arrest reduces mortality and improves neurological outcome. Experimental TH after traumatic brain injury (TBI) indicated similar effects, but benefits were not reproducible in large clinical trials. Therefore, a novel approach of pharyngeal selective brain cooling (pSBC) was tested in respect to neurological outcome in a model of experimental TBI. Male Sprague-Dawley rats were subjected to lateral fluid percussion (LFP) brain injury and received pSBC for 3h post-injury. All animals were examined for neuromotor and sensorimotor dysfunction and coordination: before and after injury, and during recovery on day post-injury (DPI) 7 and 14 using (i) the standardized Composite Neuroscore (NS) test and (ii) the Rotarod test. Recovery of cognitive function was assessed on days 10-14 using (iii) the Barnes Circular Maze (BCM). In pSBC-animals, brain temperature was selectively lowered to 33 +/- 0.5 degrees C at 15 min post-injury, keeping rectal temperature at a physiologic level. All animals subjected to TBI via LFP showed an identical pattern of severe neurofunctional impairment at 24 h after injury. In the time course of the experiment, pSBC-animals showed superior neurofunctional recovery on DPI 7 (p = 0.03) and 14 (p = 0.002). Similarly, distance, time, and maximum speed on the Rota-Rod were significantly increased in pSBC-animals on DPI 7 (p < 0.01) and 14 (p < 0.01), as well as latency, distance, and mean number of errors in the BCM on DPI 14 (p < 0.01). The novel approach of pSBC was associated with improved neuromotor, sensormotor, and neurocognitive outcome after experimental TBI.

"The good into the pot, the bad into the crop!"--a new technology to free stem cells from feeder cells

A variety of embryonic and adult stem cell lines require an initial co-culturing with feeder cells for non-differentiated growth, self renewal and maintenance of pluripotency. However for many downstream ES cell applications the feeder cells have to be considered contaminations that might interfere not just with the analysis of experimental data but also with clinical application and tissue engineering approaches. Here we introduce a novel technique that allows for the selection of pure feeder-freed stem cells, following stem cell proliferation on feeder cell layers. Complete and reproducible separation of feeder and embryonic stem cells was accomplished by adaptation of an automated cell selection system that resulted in the aspiration of distinct cell colonies or fraction of colonies according to predefined physical parameters. Analyzing neuronal differentiation we demonstrated feeder-freed stem cells to exhibit differentiation potentials comparable to embryonic stem cells differentiated under standard conditions. However, embryoid body growth as well as differentiation of stem cells into cardiomyocytes was significantly enhanced in feeder-freed cells, indicating a feeder cell dependent modulation of lineage differentiation during early embryoid body development. These findings underline the necessity to separate stem and feeder cells before the initiation of in vitro differentiation. The complete separation of stem and feeder cells by this new technology results in pure stem cell populations for translational approaches. Furthermore, a more detailed analysis of the effect of feeder cells on stem cell differentiation is now possible, that might facilitate the identification and development of new optimized human or genetically modified feeder cell lines.

Incidence and outcome of traumatic brain injury in an urban area in Western Europe over 10 years

INTRODUCTION

Valid epidemiological data on incidence and outcome of traumatic brain injury (TBI) show great variability. A study on incidence, severity and outcome of TBI was conducted in an urban area of one million inhabitants.

MATERIALS AND METHODS

130,000 prehospital emergencies were screened for TBI.

INCLUSION CRITERIA

Glasgow Coma Scale (GCS) score <or=8 and/or Abbreviated Injury Scale for head injuries (AIS(head)) score >or=2 with confirmed TBI via appropriate diagnostics.

RESULTS

Annual incidence was 7.3/100,000. Overall mortality rate was 45.8%: 182 (28%) were prehospital deaths, 116 (17.8%) patients died in hospital. Two hundred and fourteen of 352 (60.8%) surviving patients were sufficiently rehabilitated at discharge [Glasgow Outcome Scale (GOS) score = 1], but 138 patients (39.2%) survived with persisting deficits. GOS was associated with initial GCS and AIS(head).

CONCLUSION

The incidence of TBI was lower compared to the literature. The overall mortality was high, especially prehospital and early in-hospital mortality rates.

Neural differentiation of embryonic stem cells is induced by signalling from non-neural niche cells

BACKGROUND/AIMS

Embryonic stem cell (ESC) transplantation offers new therapeutic strategies for neurodegenerative diseases and injury. However, the mechanisms underlying integration and differentiation of engrafted ESCs are poorly understood. This study elucidates the influence of exogenous signals on ESC differentiation using in vitro modelling of non-stem/stem cell interactions.

METHODS

Murine ESCs were co-cultured with endothelial cells and astrocytes or conditioned medium obtained from endothelial or astrocyte cultures. After 7 days of co-culture isolated RNA was analysed using RT-PCR for the expression of pluripotency marker oct-4, neural progenitor marker nestin, and neurofilament (NFL), an early marker of neuronal lineage commitment. The presence of the glial cell surface marker A2B5 was determined in ESCs by flow cytometry.

RESULTS

Neuronal differentiation was inhibited in ESCs when grown in close vicinity to cerebral endothelial or glial cells. Under these conditions, ESC differentiation was predominantly directed towards a glial fate. However, treatment of ESCs with endothelial cell- or astrocyte-conditioned medium promoted neuronal as well as glial differentiation.

CONCLUSION

Our results indicate that ESC fate is determined by endothelial and glial cells that comprise the environmental niche of these stem cells in vivo. The direction of differentiation processes appears to be dependent on humoral factors secreted by adjacent cell lines.

Intracoronary enalaprilat during angioplasty for acute myocardial infarction: alleviation of postischaemic neurohumoral and inflammatory stress?

AIM

Reperfusion after myocardial ischaemia is associated with a distinct ischaemia/reperfusion injury. Since ACE-inhibition, beyond its influence on cardiac angiotensin II formation and kinin metabolism, has been shown to be cardioprotective by decreasing leucocyte adhesion and endothelin-1 (ET-1) release, we investigated the effects of intracoronary (i.c.) enalaprilat during primary angioplasty in acute myocardial infarction.

METHODS AND RESULTS

Twenty-two patients were randomized to receive i.c. enalaprilat (50 micro g) or placebo immediately after reopening of the infarct-related artery (IRA). Plasma concentrations of soluble L-selectin, P-selectin, intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), ET-1 and nitric oxide metabolite concentrations (NOx) were measured in pulmonary arterial blood. Coronary blood flow was assessed using corrected thrombolysis in myocardial infarction (TIMI) frame counts (CTFC). During reperfusion, there was a significant increase in sL-selectin, sP-selectin and ET-1 in the placebo group, which was greatly diminished by enalaprilat. Levels of sVCAM-1 and sICAM-1 were not affected in either group. CTFC in the placebo group remained higher than normal in both the IRA and nonculprit vessels, whereas myocardial blood flow improved with enalaprilat.

CONCLUSION

Enalaprilat as adjunct to primary angioplasty might be a protective approach to prevent leucocyte adhesion and the release of ET-1, thereby improving coronary blood flow.

Alpha-fetoprotein-positive carcinoma of the pancreas: a case report

We report on the case of a 19-year-old male with an alpha-fetoprotein (AFP)-producing acinar cell carcinoma of the pancreas. Tumour markers other than AFP were normal. Because of inoperability, a combined radiochemotherapy was initiated with a hyperfractionated dose of 44.8 Gy. Initially, the tumour showed a good response to irradiation and 5-fluorouracil (5-FU) application, and therapy showed sufficient local control. After combined radio-chemotherapy, AFP levels declined from about 3000 ng/ml (reference area: 0-7 ng/ml) to 18 ng/ml, but increased when widespread metastasis appeared. The patient died 18 months after the initial therapy due to general tumour progression. Originally, AFP was thought to be specific to hepatocellular carcinoma and germ cell tumours. Rarely has it been reported in other malignancies. Rare cases of acinar cell carcinomas of the pancreas were found to express AFP. Our patient is the youngest reported in the literature to date. When present, AFP expression is useful for diagnosis and as a marker for monitoring therapeutic response and recurrence of the disease.

THE CAPACITY OF α2-MACROGLOBULIN TO INHIBIT AN EXOGENOUS PROTEASE IS SIGNIFICANTLY INCREASED IN CRITICALLY ILL AND SEPTIC PATIENTS

The image of alpha2-macroglobulin is based on a paradigm evolved in the 1970s. During this decade alpha2-macroglobulin was shown to irreversibly entrap and thereby inhibit a maximum of two proteases. Additional binding of nonproteolytic proteins, i.e., inflammatory mediators and growth factors, is dependent on the conformational status of alpha2-macroglobulin. It was our aim to clarify whether the interaction of nonproteolytic proteins with alpha2-macroglobulin during inflammatory conditions might also modulate the capacity of alpha2-macroglobulin to inhibit proteases. To explore this possibility, bromelain, an exogenous protease, was titrated against plasma of critically ill or septic patients, whose pathophysiological conditions are defined by a massive release of inflammatory mediators. The stoichiometry of bromelain inhibition by alpha2-macroglobulin was quantified by caseolytic activity assays. The maximal alpha2-macroglobulin/bromelain inhibition ratios were significantly increased (1:6 and 1:8 in the two patient groups, P < 0.01) as compared with control groups (1:2 with purified alpha2-macroglobulin and 1:4 in healthy volunteers). The increase of alpha2-macroglobulin inhibition capacity in patients was paralleled by the appearance of a large signal on Western blots, suggesting the formation of additional complexes. Our results demonstrate alpha2-macroglobulin to have more flexibility than had been thought, and it may thereby contribute to a shift in a 30-year-old paradigm.

Polyclonal anti-histamine H2 receptor antibodies detect differential expression of H2 receptor protein in primary vascular cell types

OBJECTIVE AND DESIGN

One of the factors defining cellular response might be the distribution and density of receptor subtypes on cell membranes. It was our aim to quantify and compare histamine H2 receptor expression in primary vascular cell types. We have therefore generated antibodies directed against the second extra-cellular loop of the H2 receptor.

METHODS

The specificity of polyclonal anti-H2 receptor antibodies designed for this purpose was examined by Western blot analysis and immunohistochemistry. H2 receptor expression was quantified by ELISA. Regulation of H2 receptor gene expression was analyzed by competitive RT-PCR.

RESULTS

Our results indicate that the polyclonal antibodies specifically interact with the histamine H2 receptor. Furthermore, utilizing these antibodies we were able to show significant differences in H2 receptor levels in human umbilical arterial and vein endothelial cells as well as smooth muscle cells.

CONCLUSIONS

We conclude that the antibodies generated against the extra-cellular domain of the H2 receptor are specific and can be utilized to detect and quantify H2 receptor expression. Furthermore, the significant differences in H2 receptor expression in different vascular cell types might play a critical role in defining histamine induced cellular responses during physiological or pathophysiological processes.

Nitric oxide mediates histamine induced down-regulation of H 2 receptor mRNA and internalization of the receptor protein (R1)

During agonist-dependent long-term stimulation of cells, histamine receptor subtypes are frequently down-regulated. However, the mechanisms underlying the modulation of receptor expression during long-term histamine stimulation have yet to be resolved. Based on our recently reported results showing an H1-mediated down-regulation of histamine H2 receptor mRNA in endothelial cells, our aim was to characterize the mechanism controlling rapid and long-term histamine-mediated modulation of H2 receptor expression in more detail. We were able to show that the histamine-induced down-regulation of H2 receptor mRNA and cell surface expression lasting for 24 h was accompanied by augmentation of the receptor protein level in the cytoplasmatic fraction of endothelial cells for this time period. Furthermore, changes in receptor protein levels in whole-cell lysate were negligible, indicating that the rapid and prolonged modulation of cell surface H2 receptor levels by histamine was regulated solely via internalization. The role of nitric oxide (NO) as a key mediator in histamine-stimulated cell responses was underlined by subsequent studies showing the attenuation of histamine-induced H2 receptor mRNA down-regulation and protein trafficking following NO synthase isozyme inhibition.