Simultaneous Transplantation of Fetal Ventral Mesencephalic Tissue and Encapsulated Genetically Modified Cells Releasing GDNF in a Hemi-Parkinsonian Rat Model of Parkinson's Disease.

Transplantation of fetal ventral mesencephalic (VM) neurons for Parkinson's disease (PD) is limited by poor survival and suboptimal integration of grafted tissue into the host brain. In a 6-hydroxydopamine rat model of PD, we investigated the feasibility of simultaneous transplantation of rat fetal VM tissue and polymer-encapsulated C2C12 myoblasts genetically modified to produce glial cell line-derived neurotrophic factor (GDNF) or mock-transfected myoblasts on graft function. Amphetamine-induced rotations were assessed prior to transplantation and 2, 4, 6 and 9 wk posttransplantation. We found that rats grafted with VM transplants and GDNF capsules showed a significant functional recovery 4 wk after implantation. In contrast, rats from the VM transplant and mock-capsule group did not improve at any time point analyzed. Moreover, we detected a significantly higher number of tyrosine hydroxylase immunoreactive (TH-ir) cells per graft (2-fold), a tendency for a larger graft volume and an overall higher TH-ir fiber outgrowth into the host brain (1.7-fold) in the group with VM transplants and GDNF capsules as compared to the VM transplant and mock-capsule group. Most prominent was the TH-ir fiber outgrowth toward the capsule (9-fold). Grafting of GDNF-pretreated VM transplants in combination with the implantation of GDNF capsules resulted in a tendency for a higher TH-ir fiber outgrowth into the host brain (1.7-fold) as compared to the group transplanted with untreated VM transplants and GDNF capsules. No differences between groups were observed for the number of surviving TH-ir neurons or graft volume. In conclusion, our findings demonstrate that simultaneous transplantation of fetal VM tissue and encapsulated GDNF-releasing cells is feasible and support the graft survival and function. Pretreatment of donor tissue with GDNF may offer a way to further improve cell transplantation approaches for PD.

Chromoendoscopy in combination with random biopsies does not improve detection of gastric cancer foci in CDH1 mutation positive patients.

Background and study aims: Hereditary diffuse gastric cancer (HGGC), an autosomal dominant tumor-syndrome, accounts for 1 % to 3 % of gastric cancers worldwide. Presumably 30 % to 40 % of all patients fulfilling the clinical guidelines for HDGC are carriers of a pathogenic mutation in the CDH1 gene. Patients often show multiple foci of signet ring cell carcinoma at early age and are advised to undergo prophylactic total gastrectomy (PTG). Our aim was to improve the endoscopic detection of HDGC by using an enhanced endoscopic protocol. Patient and methods: Patients with a proven CDH1 germline mutation identified in our institute were prospectively included. Patients were advised to undergo PTG and offered a baseline endoscopic examination prior surgery. Examination was performed by using high-resolution white-light endoscopy and pan-gastric chromoendoscopy with indigo carmine as dye combined with targeted and multiple random biopsies assessed by an expert histopathologist. Postoperative histopathology was compared with results from endoscopic biopsies. Results: Between September 2012 and November 2014 8 patients with a proven CDH1 germline mutation were included. We conducted 44 targeted (6.3/patient) and 225 random (32.1/patient) biopsies in 7 patients. We detected 1 gastric cancer by random biopsy (14 %). All other examinations showed no signs of cancer. Histopathology of gastrectomy specimen revealed multiple foci of gastric carcinoma in 6 patients (86 %) with a total number of 27 cancer foci. Conclusions: Examination with targeted and random biopsies combined with chromoendoscopy is not able to detect small foci of gastric cancer in CDH1 mutation carriers. Therefore PTG is advocated in these patients.

Genome-wide CNV analysis in 221 unrelated patients and targeted high-throughput sequencing reveal novel causative candidate genes for colorectal adenomatous polyposis.

To uncover novel causative genes in patients with unexplained adenomatous polyposis, a model disease for colorectal cancer, we performed a genome-wide analysis of germline copy number variants (CNV) in a large, well characterized APC and MUTYH mutation negative patient cohort followed by a targeted next generation sequencing (NGS) approach. Genomic DNA from 221 unrelated German patients was genotyped on high-resolution SNP arrays. Putative CNVs were filtered according to stringent criteria, compared with those of 531 population-based German controls, and validated by qPCR. Candidate genes were prioritized using in silico, expression, and segregation analyses, data mining and enrichment analyses of genes and pathways. In 27% of the 221 unrelated patients, a total of 77 protein coding genes displayed rare, nonrecurrent, germline CNVs. The set included 26 candidates with molecular and cellular functions related to tumorigenesis. Targeted high-throughput sequencing found truncating point mutations in 12% (10/77) of the prioritized genes. No clear evidence was found for autosomal recessive subtypes. Six patients had potentially causative mutations in more than one of the 26 genes. Combined with data from recent studies of early-onset colorectal and breast cancer, recurrent potential loss-of-function alterations were detected in CNTN6, FOCAD (KIAA1797), HSPH1, KIF26B, MCM3AP, YBEY and in three genes from the ARHGAP family. In the canonical Wnt pathway oncogene CTNNB1 (ß-catenin), two potential gain-of-function mutations were found. In conclusion, the present study identified a group of rarely affected genes which are likely to predispose to colorectal adenoma formation and confirmed previously published candidates for tumor predisposition as etiologically relevant.

Milrinone relaxes pulmonary veins in guinea pigs and humans.

INTRODUCTION: The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans. MATERIAL AND METHODS: Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL). RESULTS: In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of K ATP-, BK Ca (2+)- and Kv-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted. DISCUSSION: Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K ATP-, BK Ca (2+)- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

Initial diagnosis of Wegener's granulomatosis mimicking severe ulcerative colitis: a case report.

INTRODUCTION: We describe the case of a woman with an unusual presentation of Wegener's granulomatosis. CASE PRESENTATION: A 20-year old Caucasian woman presented with the principal feature of a pancolonic, superficial microulceration mimicking severe ulcerative colitis. Our patient was refractory to therapy and had persisting signs of septic shock as well as being at risk of perforation, so we performed a subtotal colectomy and a cholecystectomy due to the incipient necrosis of her gallbladder. Histologic analysis of her colon showed multiple superficial microulcera of the mucosa, lamina propria mucosae and, to a lesser extent, the lamina submucosa. The medium-sized arteries and arterioles of her entire colon, appendix and gallbladder showed acute vasculitic changes with fibrinoid necrosis of the walls and diffuse infiltration with neutrophil granulocytes, accompanied by a strong perivascular histiocyte-rich and partially granulomatous reaction. These findings strongly suggested an autoimmune multisystem disease like Wegener's granulomatosis or microscopic polyangiitis. A diagnosis of Wegener's granulomatosis was confirmed by the results of serologic antibody tests: her cytoplasmic antineutrophil cytoplasmic antibody titer was considerably elevated at 1:2560 specific for subclass proteinase 3 (>200kU/L). After the histopathological diagnosis and serological tests, immunosuppression with high doses of corticosteroids and plasmapheresis was started. CONCLUSION: In critically ill patients with severe, therapy-refractory ulcerative colitis, Wegener´s granulomatosis should be considered and serologic antibody testing should be performed.

Neurally mediated airway constriction in human and other species: a comparative study using precision-cut lung slices (PCLS).

The peripheral airway innervation of the lower respiratory tract of mammals is not completely functionally characterized. Recently, we have shown in rats that precision-cut lung slices (PCLS) respond to electric field stimulation (EFS) and provide a useful model to study neural airway responses in distal airways. Since airway responses are known to exhibit considerable species differences, here we examined the neural responses of PCLS prepared from mice, rats, guinea pigs, sheep, marmosets and humans. Peripheral neurons were activated either by EFS or by capsaicin. Bronchoconstriction in response to identical EFS conditions varied between species in magnitude. Frequency response curves did reveal further species-dependent differences of nerve activation in PCLS. Atropine antagonized the EFS-induced bronchoconstriction in human, guinea pig, sheep, rat and marmoset PCLS, showing cholinergic responses. Capsaicin (10 µM) caused bronchoconstriction in human (4 from 7) and guinea pig lungs only, indicating excitatory non-adrenergic non-cholinergic responses (eNANC). However, this effect was notably smaller in human responder (30 ± 7.1%) than in guinea pig (79 ± 5.1%) PCLS. The transient receptor potential (TRP) channel blockers SKF96365 and ruthenium red antagonized airway contractions after exposure to EFS or capsaicin in guinea pigs. In conclusion, the different species show distinct patterns of nerve-mediated bronchoconstriction. In the most common experimental animals, i.e. in mice and rats, these responses differ considerably from those in humans. On the other hand, guinea pig and marmoset monkey mimic human responses well and may thus serve as clinically relevant models to study neural airway responses.

Web-based virtual microscopy at the RWTH Aachen University: didactic concept, methods and analysis of acceptance by the students.

Fundamental knowledge of microscopic anatomy and pathology has always been an essential part in medical education. The traditional didactic concept comprises theoretical and practical lessons using a light microscope and glass slides. High-speed Internet connections and technical improvement in whole-slide digital microscopy (commonly termed "virtual microscopy") provide a new and attractive approach for both teachers and students. High picture quality and unlimited temporal and spatial availability of histology samples from different fields are key advantages of web-based digital microscopy. In this report we discuss the technical requirements, system efficiency, optical resolution and didactic concept. Furthermore, we present a review of the experience gained in the course of one year based on an analysis of student acceptance. Three groups with a total of 192 students between the 3rd and 5th year of medical studies attending the practical courses of general and advanced histopathology had access to both glass-mounted and digitalized slides. Prior to exams, students were asked to answer an anonymous questionnaire. The results of the study reflect the high acceptance and intensive use of the web-based digital histology by students, thus encouraging the development of further Web-based learning strategies for the teaching of histology and pathology.

Long-term survival and characterisation of human umbilical cord-derived mesenchymal stem cells on dermal equivalents.

During early embryogenesis, mesenchymal cells arise from the primitive epithelium and can revert to an epithelial phenotype by passing through mesenchymal-to-epithelial transition (MET). Mesenchymal stem cells (MSC) of the Wharton's Jelly of the umbilical cord (UC-MSC) express pluripotency markers underlining their primitive developmental state. As mesenchymal stem cells from bone marrow (BM-MSC) possess a strong propensity to ameliorate mesenchymal tissue damage, UC-MSC might also be able to differentiate into cells apart from the mesoderm, allowing replacement of ectodermal and mesodermal tissues. In this study, we analysed the possible epidermal differentiation of UC-MSC on dermal equivalents (DEs) consisting of collagen I/III with dermal fibroblasts and subjected to the culture conditions for tissue engineering of skin with keratinocytes. The culture conditions were further modified by pre-treating the cells with 5-azacytidine or by supplementing the medium with all trans retinoic acid. Interestingly, a subpopulation of UC-MSC (29%) co-expressed pan-cytokeratin (epithelial marker; pan-CK) and vimentin (mesenchymal marker) after isolation. Under the three-dimensional conditions of skin, the number of pan-CK(+)-cells increased to >30% after 21 days of cultivation, while under osteogenic culture conditions the cells were pan-CK-negative, thus showing the influence of the artificial niche. Nevertheless, the pan-CK-expression was neither accompanied by typical epithelial morphology nor expression of other epidermal markers. The pan-CK-detection can be explained by the expression of cytokeratins in myofibroblasts. UC-MSC expressed alpha-smooth muscle actin after isolation and displayed all features of functional myofibroblasts like morphology, cell-mediated contraction of a collagen gel and production of components of the extracellular matrix (ECM). The treatment with all trans retinoic acid or 5-azacytidine could neither induce an epidermal differentiation nor enhance the myofibroblastic differentiation. Concluding, UC-MSC might be an interesting cell source to support the regeneration of wounds by their differentiation into myofibroblasts and their extensive synthesis of ECM components.

The osteogenic differentiation of adult bone marrow and perinatal umbilical mesenchymal stem cells and matrix remodelling in three-dimensional collagen scaffolds.

Adult human mesenchymal stem cells from bone marrow (BM-MSC) represent a promising source for skeletal regeneration. Perinatal MSC from Wharton's Jelly of the umbilical cord (UC-MSC) are expected to possess enhanced differentiation capacities due to partial expression of pluripotency markers. For bone tissue engineering, it is important to analyse in vitro behaviour of stem cell/biomaterial hybrids concerning in vivo integration into injured tissue via migration, matrix remodelling and differentiation. This study compares the cell-mediated remodelling of three-dimensional collagen I/III gels during osteogenic differentiation of both cell types. When activated through collagen contact and subjected to osteogenic differentiation, UC-MSC differ from BM-MSC in expression and synthesis of extracellular matrix (ECM) proteins as shown by histology, immunohistochemistry, Western Blot analysis and realtime-RT-PCR. The biosynthetic activity was accompanied in both cell types by the ultrastructural appearance of hydroxyapatite/calcium crystals and osteogenic gene induction. Following secretion of matrix metalloproteinases (MMP), both MSC types migrated into and colonised the collagenous matrix causing matrix strengthening and contraction. These results indicate that UC-MSC and BM-MSC display all features needed for effective bone fracture healing. The expression of ECM differs in both cell types considerably, suggesting different mechanisms for bone formation and significant impact for bone tissue engineering.

The use of a shape-memory poly(epsilon-caprolactone)dimethacrylate network as a tissue engineering scaffold.

Shape-memory polymers produced from many natural or synthetic raw polymers are able to undergo a shape transformation after exposure to a specific external stimulus. This feature enables their use in minimal-invasive surgery with a small, compact starting material switching over to a more voluminous structure in the body. The use of biomaterials in modern medicine calls for compatibility tests with cell types, encountering the biomaterial during a short-term or long-term in vivo application. We analysed the cell behaviour of L929 mouse fibroblasts, human mesenchymal stem cells, human mesothelial cells and rat mesothelial cells on a biodegradable shape-memory polymer network to assess its suitability for medical applications. Further, we investigated the differentiation capacity of mesenchymal stem cells into osteoblasts and adipocytes on the polymer and we analysed the influence of the shape-memory effect on adherent cells. The polymer was cytocompatible for all tested cell types, supporting cell viability and proliferation. The differentiation capacity of mesenchymal stem cells was supported by the polymer and shape-memory effect activation did not affect the majority of adherent cells.

Magnetic resonance-guided angioplasty with delivery of contrast-media doped solutions to the vessel wall: an experimental study in swine.

OBJECTIVES: To assess the feasibility of magnetic resonance (MR)-guided delivery of a solution containing contrast-medium and immediate online monitoring of its distribution to the vessel wall during MR-guided angioplasty in peripheral arteries. MATERIALS AND METHODS: In 3 pigs, the feasibility of MR-guided atraumatic delivery of a solution containing contrast-medium and tissue dye (0.05 mmol/mL Gd-DTPA, 3% Evans blue dye) into the vessel wall of the iliac arteries was tested using a permeable balloon catheter (8 mm). Catheter placement was monitored using a steady-state free precession real-time imaging sequence.Additionally, in 5 pigs, surgically created bilateral stenoses in the external iliac artery were dilatated with the porous balloon. In these animals, contrast-enhanced MR angiography was performed before and after the interventions to assess the degree of the stenosis. In all animals, the vessel wall was delineated before and after dilatation using a T1-weighted gradient echo (GE) sequence. RESULTS: In the 3 animals without stenosis, contrast medium was successfully applied to the vessel wall. On the GE images, the normalized signal intensity of the vessel wall was 0.95 +/- 0.015 arbitrary units (a. u.) prior and 2.15 +/- 0.105 a. u. after the intervention (P < 0.01). In the animals with stenosis, MR angiography performed before and after the intervention demonstrated successful dilatation of 9 of the 10 stenoses. Before the intervention, 7 stenoses were severe (76%-99%) and 3 moderate (50%-75%), and after the intervention, 4 stenoses were completely removed and 5 mild (<50%). Also in these 5 animals, the solution was visible in the vessel wall of the arteries on the T1-weighted GE MR images (normalized signal intensity prior the intervention 1.33 +/- 0.16 a. u. and 2.97 +/- 0.23 after angioplasty; P < 0.05). Histology demonstrated the distribution of the Evan's blue dye within the vessel wall in all animals. CONCLUSIONS: MR-guided delivery of a contrast-medium containing solution and immediate online assessment of its distribution to the vessel wall during angioplasty in peripheral arteries is feasible.

Littoral cell angioma of the spleen mimicking posttransplantation lymphoma in a 63-year-old renal transplant patient.

In addition to lymphomas, vascular tumors represent the most common neoplasms of the spleen. Littoral cell angiomas are benign vascular tumors originating from the littoral cells lining the splenic sinuses. In this report, we describe the case of a 63-year-old patient who developed night sweats 16 months after renal transplantation. Diagnostic workup showed multiple splenic masses believed to represent lymphoma infiltration to the spleen. Lymph nodes and bone marrow were unaffected, and diagnostic splenectomy was performed. Histological examination of the pathological specimen from the splenectomy specimen showed multiple littoral cell angiomas of the spleen. We recommend that physicians involved in the area of organ transplantation, especially kidneys, remain alert for other rarer splenic lesions in transplant recipients than posttransplantation lymphoma. More specific tools need to be developed to aid in the differential diagnosis of splenic masses to avoid splenectomy in patients with littoral cell angiomas.

Selective left ventricular adriamycin-induced cardiomyopathy in the pig.

OBJECTIVE: The aim of this study was the development of an experimental cardiomyopathy induced with Adriamycin (Pharmacia & Upjohn, Erlangen, Germany) with selective toxic damage of the left ventricular myocardium that avoided an ischemic component. METHODS: An intracoronary catheter was implanted directly into the left main stem in pigs and connected to a percutaneous access port that was used for repetitive Adriamycin administration (3-5 x 25 mg weekly over a 1-hour period). Hemodynamic and echocardiographic variables were measured before Adriamycin administration, 1 week after, and at 4 weeks. Thereafter, all hearts were autopsied for detailed histologic examination. Statistical analysis was done by an analysis of variance for multiple parameters. RESULTS: All pigs had normal baseline cardiac function. Measurements after Adriamycin administration and 4 weeks later demonstrated a continued increase of the central venous pressure, pulmonary artery pressure, pulmonary wedge pressure, and pulmonary vascular resistance, whereas cardiac output, stroke volume index, and left ventricular stroke work index decreased. These results were supported by the echocardiographic data depicting an increase of left ventricular diameters and volumes, accompanied by a decrease of intraventricular and left ventricular posterior wall thickness as well as left ventricular ejection fraction. Right ventricular volumes and function did not change during the trial. The histologic examination of the hearts revealed a selective toxic damage of the left ventricular myocardium with multifocal necroses and advanced tissue reorganization. CONCLUSION: This animal model creates a selective left ventricular damage that avoids ischemic damage of the myocardium. Both aspects can improve research on Adriamycin-induced cardiomyopathy, especially preventive or therapeutic strategies.

Assessment of stem cell/biomaterial combinations for stem cell-based tissue engineering.

Biomaterials are used in tissue engineering with the aim to repair or reconstruct tissues and organs. Frequently, the identification and development of biomaterials is an iterative process with biomaterials being designed and then individually tested for their properties in combination with one specific cell type. However, recent efforts have been devoted to systematic, combinatorial and parallel approaches to identify biomaterials, suitable for specific applications. Embryonic and adult stem cells represent an ideal cell source for tissue engineering. Since stem cells can be readily isolated, expanded and transplanted, their application in cell-based therapies has become a major focus of research. Biomaterials can potentially influence e.g. stem cell proliferation and differentiation in both, positive or negative ways and biomaterial characteristics have been applied to repel or attract stem cells in a niche-like microenvironment. Our consortium has now established a grid-based platform to investigate stem cell/biomaterial interactions. So far, we have assessed 140 combinations of seven different stem cell types and 19 different polymers performing systematic screening assays to analyse parameters such as morphology, vitality, cytotoxicity, apoptosis, and proliferation. We thus can suggest and advise for and against special combinations for stem cell-based tissue engineering.

Three-dimensional epidermis-like growth of human mesenchymal stem cells on dermal equivalents: contribution to tissue organization by adaptation of myofibroblastic phenotype and function.

Human mesenchymal stem cells (hMSC) are able to differentiate into mature cells of various mesenchymal tissues. Recent studies have reported that hMSC may even give rise to cells of ectodermal origin. This indication of plasticity makes hMSC a promising donor source for cell-based therapies. This study explores the differentiation potential of hMSC in a tissue-specific microenvironment simulated in vitro. HMSC were cultured air-exposed on dermal equivalents (DEs) consisting of collagen types I and III with dermal fibroblasts and subjected to conditions similar to those used for tissue engineering of skin with keratinocytes. Culture conditions were additionally modified by pre-treating the cells with 5-azacytidine or supplementing the medium with all trans retinoic acid (RA). HMSC were capable of adaptation to epidermis-specific conditions without losing their mesenchymal multipotency. However, despite the viability and evident three-dimensional epidermis-like growth pattern, hMSC showed a persistent expression of mesenchymal but not of epithelial markers, thus indicating a lack of epidermal (trans) differentiation. Further, electron microscopy and immunohistochemical analyses demonstrated that hMSC cultured under epidermis-specific conditions adopted a myofibroblastic phenotype and function, promoted in particular by air exposure. In conclusion, multipotent hMSC failed to differentiate into E-cadherin- or cytokeratin-expressing cells under optimized organotypic culture conditions for keratinocytes but differentiated into myofibroblast-like cells contracting the extracellular matrix, a phenomenon that was enhanced by RA and 5-azacytidine. These results indicate that hMSC might contribute to wound-healing processes by extracellular matrix reorganization and wound contraction but not by differentiation into keratinocytes.

Fibromatosis-like myofibroblastic tumour of forearm: case report and interdisciplinary management.

We present a rare case of a fibromatosis-like myofibroblastic tumour of the forearm with infiltration of muscular, neural, and vascular structures. This is a rare and transitional type of myofibroblastic tumour, and we emphasise important aspects of diagnosis, clinical features, interdisciplinary management, and differential diagnoses.

In vivo experimental testing of a microaxial blood pump for right ventricular support.

The incidence of isolated right ventricular (RV) failure is rare in postcardiotomy patients, but high in patients undergoing implantation of a left ventricular assist device or cardiac transplantation. Therefore, we have developed a new microaxial flow device and report on our first in vivo animal trials. Six healthy adult female sheep weighing 80-90 kg underwent implantation of the microaxial blood pump for partial unloading of the right ventricle. This pump is a miniaturized rotary blood pump with a diameter of only 6.4 mm and a weight of 11 g. The inner volume of the pump is limited to 12 mL, and the inner artificial blood contacting surface is 65 cm(2). The pump consists of a rotor driven by an incorporated brushless direct current motor, the housing of the rotor, the inflow cage, the outflow cannula, and the driveline. At the maximum speed of 32,500 rotations/min, a flow of 6 L/min can be delivered. The inflow and outflow conduit were anastomosed to the right atrium and the main pulmonary artery, respectively. Hemodynamic and echocardiographic data as well as blood samples were measured over the whole test period of 7 days. The hearts and lungs as well as the pump were explanted for a thorough examination at the end of the trial. Systemic arterial blood pressures remained unchanged during the entire test period. RV cardiac output was diminished significantly as demonstrated by the echocardiographic studies. The number of platelets decreased perioperatively, but recovered within the test period. The free hemoglobin was not enhanced postoperatively indicating no significant hemolysis. Liver function was only slightly impaired due to operative reasons (increase in bilirubin on the first postoperative day but normalization within the test period). The pathologic examination revealed some clots at the inflow cage and fibrin depositions on the impeller as well as on the inner surface of the outflow graft without an impairment of pump function. Our results demonstrate that this newly developed microaxial blood pump is a promising device for RV support, but it cannot be driven without any anticoagulation.

Creatine supplementation improves dopaminergic cell survival and protects against MPP+ toxicity in an organotypic tissue culture system.

Cell replacement therapy using mesencephalic precursor cells is an experimental approach for the treatment of Parkinson's disease (PD). A significant problem associated with this procedure is the poor survival of grafted neurons. Impaired energy metabolism is considered to contribute to neuronal cell death after transplantation. Creatine is a substrate for mitochondrial and cytosolic creatine kinases (CK) and buffers cellular ATP resources. Furthermore, elevated cellular creatine levels facilitate metabolic channeling and show antiapoptotic properties. Exogenous creatine supplementation therefore might offer a tool for improvement of dopaminergic neuron survival. The present study aimed at investigating the effects of creatine on cell survival of rat embryonic day 14 (E14) ventral mesencephalic neurons grown as organotypic free-floating roller tube (FFRT) cultures. We found that the brain-specific isoform of CK (BB-CK) and the ubiquitous mitochondrial isoform (uMt-CK) are expressed at high levels in FFRT cultures and colocalize with tyrosine hydroxylase immunoreactive (TH-ir) cells. Exposure of these cultures to creatine induced an increase in the content of the BB-CK isotype. Creatine (5 mM) administration starting at day in vitro (DIV) 7 resulted in a significant increase (+35%) in TH-ir cell density at DIV21. In addition, we observed that creatine treatment provided neuroprotection against 1-methyl-4-phenyl pyridinium ion (MPP+)-induced TH-ir cell loss in the FFRT culture system, resulting in a significantly higher density (+19%) of TH-ir neurons in creatine-treated cultures compared to corresponding controls. The decrease of TH-ir neurons in the MPP+-treated group corresponded with an increase in immunoreactivity for active caspase-3, an effect that was not seen in the group receiving creatine supplementation. In conclusion, our data imply that creatine administration is beneficial for the survival of TH-ir neurons encountering harmful conditions.

ES cell-derived glial precursors contribute to remyelination in acutely demyelinated spinal cord lesions.

Pluripotent embryonic stem (ES) cells have emerged as a powerful tool for disease modeling and neural regeneration. Transplantation studies in rodents indicate that ES cell-derived glial precursors (ESGPs) efficiently restore myelin in dysmyelinating mutants and chemically induced foci of myelin loss. Here we explore the myelination potential of ESGPs in an antibody/complement-induced demyelination model. Microinjection of an antibody to myelin oligodendrocyte glycoprotein (MOG) and complement was employed to generate circumscribed areas of demyelination in the adult rat spinal cord. ESGPs transplanted into 2-day-old lesions were found to survive and differentiate into both oligodendrocytes and astrocytes. The engrafted cells remained largely confined to the lesion site and showed no evidence of tumor formation up until 4 weeks after transplantation. Within areas of pronounced microglial activation and macrophage extravasation, engrafted ES cell-derived oligodendrocytes contacted and enwrapped host axons and alongside endogenous glia, contributed to the formation of new myelin sheaths. These findings demonstrate that ESGPs transplanted into acutely demyelinated lesions can contribute to myelin repair.