GPR15-mediated T cell recruitment during acute viral myocarditis is associated with improved virus elimination and outcome

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK

Ernst und Berta Grimmke Stiftung

Background

Myocarditis is an inflammatory disease of the myocardium indicated by mononuclear cell infiltration. It is predominantly caused by infectious agents such as coxsackievirus B3 (CVB3). Especially in young adults, myocarditis is a major source of sudden cardiac arrest. However, its clinical course has a broad spectrum of outcomes, ranging from mild symptoms and complete recovery to cardiac dysfunction and dilated cardiomyopathy. G protein-coupled receptor 15 (GPR15) was identified as a T cell homing receptor in the context of inflammatory intestine and skin diseases. We found Gpr15 to be highly upregulated in the left ventricle (LV) 7 days after CVB3 infection in wild type (WT) mice.

Purpose

GPR15 has not been described in a cardiac context, yet. Our aim was to investigate the role of GPR15 in recruiting immune cell subsets and later in virus elimination during viral myocarditis.

Methods

Gpr15 deficient (Gpr15gfp/gfp) and WT mice were infected intraperitoneal with CVB3 to investigate the acute (6 & 7 days post infection(p.i.)) and the subacute phase (16 days p.i.) of myocarditis. To study differentially expressed genes, LV tissue was used for TaqMan analysis and RNA-sequencing. Inflammation and fibrosis were evaluated on histological level. For functional characterization, healthy and diseased mice were hemodynamically characterized 16 days p.i.. Furthermore, in vitro migration assays were used to study the interaction between GPR15 and its ligands in vitro.

Results

Infected Gpr15gfp/gfp mice exhibited higher upregulation of immune response related genes on mRNA level in the acute phase of myocarditis 7 days p.i.. For instance, Cd8a, a cytotoxic T cell marker, and Foxp3, a regulatory T cell marker, were significantly higher in infected Gpr15gfp/gfp compared to infected WT mice. Bulk RNA-sequencing confirmed that the response to virus did not decline from day 6 to 7 in infected GPR15-deficient mice as observed in infected WT mice. Subsequent gene ontology (GO) term analyses reveled enhanced chemotaxis and cytotoxic T cell-related GO terms in GPR15-deficient mice on day 7.

Among investigated T cell subsets, GPR15 was highest expressed on CD8+ T cell. Its deficiency abolished chemotaxis of T cells, especially of cytotoxic T cells, towards GPR15 ligand in vitro.

In the subacute phase of myocarditis 16 days p.i., viral persistence was observed in more than 85 % of Gpr15gfp/gfp mice. In contrast, more than 70 % of WT mice with verified viremia cleared the virus successfully. Furthermore, Gpr15gfp/gfp mice demonstrated a decreased cardiac function accompanied by increased fibrosis in comparison to WT mice.

Conclusion

Our findings indicate that despite the prolonged inflammatory response, scant virus elimination was presumably caused by decelerated recruitment of cytotoxic T cells leading to impaired outcome in the GPR15-deficient mice.

The Multiple Sclerosis Inventory of Cognition for Adolescents (MUSICADO): A brief screening instrument to assess cognitive dysfunction, fatigue and loss of health-related quality of life in pediatric-onset multiple sclerosis

OBJECTIVE

Screening for cognitive impairment (CI), fatigue and also Health-related quality of life (HRQoL) in patients with pediatric-onset multiple sclerosis (POMS) is of utmost importance in clinical practice. The aim of this study was to establish a new and validated pediatric screening tool "MUSICADO" that is easy to use and time economical.

METHODS

106 patients with POMS aged 12-18 years and 210 healthy controls (HCs) stratified for age and education underwent neuropsychological testing including a screening test "Multiple Sclerosis Inventory of Cognition" for adults and 8 standardized cognitive tests and established scales to assess fatigue and HRQoL.

RESULTS

The phonemic verbal fluency task (RWT "s-words"), the Trail Making Test A (TMT-A), and the Digit Span Forward discriminated significantly between patients and HCs (p = 0.000, respectively) and showed the highest proportion of test failure in patients (24.5%, 17.9%; 15.1%, respectively). Therefore, they were put together to form the cognitive part of the "MUSICADO". After applying a scoring algorithm with balanced weighting of the subtests and age and education correction and a cut-off score for impairment, 35.8% of patients were categorized to be cognitively impaired (specificity: 88.6%). Fatigue was detected in 37.1% of the patients (specificity: 94.0%) and loss of HRQoL in 41.8% (specificity 95.7%) with the screening version, respectively.

CONCLUSION

The MUSICADO is a newly designed brief and easy to use screening test to help to early identify CI, fatigue, and loss of HRQoL in patients with POMS as cut scores are provided for all three items. Further studies will have to show its usability in independent samples of patients with POMS.

Solid-phase combinatorial synthesis using microarrays of microcompartments with light-induced on-chip cell screening

The process of drug discovery includes individual synthesis and characterization of drug candidates, followed by a biological screening, which is separated from synthesis in space and time. This approach suffers from low throughput and associated high costs, which in turn lead to inefficiency in the field of drug discovery. Here, we present a miniaturized platform combining combinatorial solid-phase synthesis with high-throughput cell screenings. The method is based on the formation of nanoporous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) layers patterned with hydrophilic spots separated from each other by superhydrophobic liquid-impermeable barriers. The porous polymer inside the hydrophilic spots is used as a support to conduct solid-phase synthesis. The hydrophilic spots can be then filled with droplets containing either reagents for synthesis or live cells. Upon irradiation with UV light, products of solid-phase synthesis are released from the porous polymer because of the photo-cleavable linkers used and diffuse into separate droplets. The light-induced release of the products allows the control of the release spatially, temporally, and quantitatively. To demonstrate the versatility and usability of the platform for various cell lines, we have successfully implemented peptide synthesis to create an exemplary chemical library and demonstrated high cell viability after the UV-triggered small-molecule release.

Enhanced mobilization of the bone marrow-derived circulating progenitor cells by intracoronary freshly isolated bone marrow cells transplantation in patients with acute myocardial infarction

Autologous bone marrow cell transplantation (BMCs-Tx) is a promising novel option for treatment of cardiovascular disease. We analysed in a randomized controlled study the influence of the intracoronary autologous freshly isolated BMCs-Tx on the mobilization of bone marrow–derived circulating progenitor cells (BM-CPCs) in patients with acute myocardial infarction (AMI). Sixty-two patients with AMI were randomized to either freshly isolated BMCs-Tx or to a control group without cell therapy. Peripheral blood (PB) concentrations of CD34/45⁺- and CD133/45⁺-circulating progenitor cells were measured by flow cytometry in 42 AMI patients with cell therapy as well as in 20 AMI patients without cell therapy as a control group on days 1, 3, 5, 7, 8 and 3, 6 as well as 12 months after AMI. Global ejection fraction (EF) and the size of infarct area were determined by left ventriculography. We observed in patients with freshly isolated BMCs-Tx at 3 and 12 months follow up a significant reduction of infarct size and increase of global EF as well as infarct wall movement velocity. The mobilization of CD34/45⁺ and CD133/45⁺ BM-CPCs significantly increased with a peak on day 7 as compared to baseline after AMI in both groups (CD34/45⁺: P < 0.001, CD133/45⁺: P < 0.001). Moreover, this significant mobilization of BM-CPCs existed 3, 6 and 12 months after cell therapy compared to day 1 after AMI. In control group, there were no significant differences of CD34/45⁺ and CD133/45⁺ BM-CPCs mobilization between day 1 and 3, 6 and 12 months after AMI. Intracoronary transplantation of autologous freshly isolated BMCs by use of point of care system in patients with AMI may enhance and prolong the mobilization of CD34/45⁺ and CD133/45⁺ BM-CPCs in PB and this might increase the regenerative potency after AMI.

Systemic delivery of triplex-forming PNA and donor DNA by nanoparticles mediates site-specific genome editing of human hematopoietic cells in vivo

In vivo delivery is a major barrier to the use of molecular tools for gene modification. Here we demonstrate site-specific gene editing of human cells in vivo in hematopoietic stem cell-engrafted NOD.Cg-Prkdc(scid)IL2rγ(tm1Wjl) (abbreviated NOD-scid IL2rγ(null)) mice, using biodegradable nanoparticles loaded with triplex-forming peptide nucleic acids (PNAs) and single-stranded donor DNA molecules. In vitro screening showed greater efficacy of nanoparticles containing PNAs/DNAs together over PNA-alone or DNA-alone. Intravenous injection of particles containing PNAs/DNAs produced modification of the human CCR5 gene in hematolymphoid cells in the mice, with modification confirmed at the genomic DNA, mRNA and functional levels. Deep sequencing revealed in vivo modification of the CCR5 gene at frequencies of 0.43% in hematopoietic cells in the spleen and 0.05% in the bone marrow: off-target modification in the partially homologous CCR2 gene was two orders of magnitude lower. We also induced specific modification in the β-globin gene using nanoparticles carrying β-globin-targeted PNAs/DNAs, demonstrating this method's versatility. In vivo testing in an enhanced green fluorescent protein-β-globin reporter mouse showed greater activity of nanoparticles containing PNAs/DNAs together over DNA only. Direct in vivo gene modification, such as we demonstrate here, would allow for gene therapy in systemic diseases or in cells that cannot be manipulated ex vivo.

Anisotropic remastering for reducing feature sizes on UV nanoimprint lithography replica molds

We present an approach that uses existing nanoimprint molds and reduces the size of the resulting features significantly via a remastering process utilizing the anisotropic etchant tetramethylammonium hydroxide and a mold casting step. Inverted pyramidal structures and V-grooves were imprinted using these 2.5-dimensional (2.5D) replica molds. Pattern transfer into silicon (Si) substrates was established with an intermediate silicon nitride (SiN(x)) layer that can be etched with a much larger selectivity against the imprint resist than the Si substrate. The 2.5D resist profiles are thus transferred back into binary structures in the SiN(x) layer and subsequently into the Si substrate. A substantial size reduction of the diameter of pits from 91 to 33 nm and the width of lines from 600 to 142 nm was achieved.

Improved functional activity of bone marrow derived circulating progenitor cells after intra coronary freshly isolated bone marrow cells transplantation in patients with ischemic heart disease

Objectives

There is growing evidence that intracoronary autologous bone marrow cells transplantation (BMCs-Tx) in patients with chronic myocardial infarction beneficially affects postinfarction remodelling. In this randomized controlled study we analyzed the influence of intracoronary autologous freshly isolated bone marrow cells transplantation by use of point of care system on cardiac function and on the functional activity of bone marrow derived circulating progenitor cells (BM-CPCs) in patients with ischemic heart disease (IHD).

Methods

56 patients with IHD were randomized to either received freshly isolated BMC-Tx or a control group that did not receive cell therapy. The functional activity of BM-CPCs in peripheral blood (PB) was measured by migration assay and colony forming unit assay pre- and 3, 6 as well as 12 months after procedure. Global ejection fraction (EF) and infarct size area were determined by left ventriculography.

Results

Intracoronary transplantation of autologous freshly isolated BMCs led to a significant reduction of infarct size and an increase of global EF as well as infarct wall movement velocity after 3 and 12 months follow-up compared to control group. The colony-forming capacity of BM-CPCs significantly increased 3, 6 and 12 months after cell therapy compared to pre BMCs-Tx and control group (CFU-E: p < 0.001, CFU-GM: p < 0.001). Likewise, we found significant increase of migratory response to stromal cell-derived factor 1 (SDF-1) and vascular endothelial growth factor (VEGF) after cell therapy compared to pre BMCs-Tx (SDF-1: p < 0.001, VEGF: p < 0.001) and to control (SDF-1: p < 0.001, VEGF: p < 0.001). There was no significant difference of migratory- and colony forming capacity between pre- and 3, 6, 12 months after coronary angiography in control group without cell therapy.

Conclusions

Intracoronary transplantation of autologous freshly isolated BMCs by use of point of care system may lead to improvement of BM-CPCs functional activity in peripheral blood, which might increase the regenerative potency in patients with IHD.

Temperature-dependent evolution of the wetting layer thickness during Ge deposition on Si(001)

The evolution of the wetting layer (WL) thickness during Ge deposition on Si(001) is analyzed with the help of a rate-equation approach. The combined role of thickness, island volume and shape-dependent chemical potentials is considered. Several experimental observations, such as WL thinning following the pyramid-to-dome transformation, are captured by the model, as directly demonstrated by a close comparison with photoluminescence measurements (PL) on samples grown at three different temperatures. The limitations of the model in describing late stages of growth are critically addressed.

Excitation Intensity Driven PL Shifts of SiGe Islands on Patterned and Planar Si(001) Substrates: Evidence for Ge-rich Dots in Islands

For randomly nucleated SiGe/Si(001) islands, a significantly stronger blue-shift of the PL spectra as a function of the excitation intensity is observed when compared to islands grown on patterned substrates side by side within the same run in a solid source molecular beam epitaxy chamber. We ascribe this different PL behavior to the much larger inhomogeneity of the Ge distribution in islands on planar substrates when compared to islands grown on pit-patterned ones, as observed previously. 3D band-structure calculations show that Ge-rich inclusions of approximately 5 nm diameter at the apex of the islands can account for the observed differences in the PL spectra. The existence of such inclusions can be regarded as a quantum dot in an island and is in agreement with recent nano-tomography experiments.

Therapeutic potentials of stem cells in cardiac diseases

Coronary heart disease and chronic heart failure are common diseases and have an increasing frequency. Although interventional and conventional drug therapy may delay ventricular remodelling, there is no basic therapeutic regime available for preventing or even reversing this process. Chronic coronary artery disease and heart failure impair quality of life and are associated with subsequent worsening of the cardiac pump function. Numerous studies carried out in the past few years have demonstrated, that the intracoronary stem cell therapy has to be considered as a safe therapeutic procedure in heart disease, when destroyed and/or compromised heart muscle must be regenerated. This kind of cell therapy with autologous bone marrow cells is completely justified ethically, except for the small numbers of patients with direct or indirect bone marrow disease (e.g. myeloma, leukemic infiltration) in whom there would be lesions of mononuclear cells. Several preclinical as well as clinical trials have shown that transplantation of autologous bone marrow cells or precursor cells improved cardiac function after myocardial infarction and in chronic coronary heart disease. The age of infarction seems to be irrelevant to regenerative potency of stem cells, since stem cells therapy in old infarctions (many years old) is almost equally effective in comparison to previous infarcts. Further indications are non-ischemic cardiomyopathy (dilatative cardiomyopathy) and heart failure due to hypertensive heart disease.

Therapeutic potential of stem cells in elderly patients with cardiovascular disease

The success of treatment for acute myocardial infarction and chronic myocardial ischemia has improved general medical care in Europe, resulting in an increasing population of patients with chronic and congestive heart failure. By applying currently available therapeutic options the quality of life and lifespan of these patients have both increased. However, amongst patients -- predominantly the elderly -- who remain symptomatic despite intensive medical treatment, autologous bone marrow-derived mononuclear cells may trigger attempts to repopulate lost tissues directly as a novel therapeutic option. In this concised paper the current understanding of stem cell therapy and early clinical experiences are discussed and related to the application of stem cells in elderly patients with myocardial ischemia.

Antenna-mediated back-scattering efficiency in infrared near-field microscopy

We evaluate the efficiency of back-scattering, eta(B), from a standard cantilevered AFM probe contacting a flat sample, and also the back-scattering phase. Both quantities are spectroscopically determined over a broad 9-12 mum wavelength range by coherent frequency-comb Fourier-transform spectroscopy (c-FTIR). While Fresnel reflectivity contributes a key factor with the SiC Reststrahlen edge at 975 cm(-1)as previously documented, we observe spectral effects ascribable to antenna resonances involving the shaft, cantilever, and sample. Most conspicuous is strong (eta(B) = 13%), resonant back-scattering at 955 cm(-1), a frequency that suggests the involvement of surface-phonon-polariton excitation, when the tip probes the area near a SiC/Au boundary. The probe's antenna properties are elucidated by numerically simulating the near fields, the fields in the radiation zone, and the far-field scattering distributions. The simulations are performed for a realistic tip/sample configuration with a three-orders-of-magnitude scale variation. The results suggest a standing-surface-plasmon-polariton pattern along the shaft, as well as far-field antenna lobes that change with the sample's dielectric properties.

The therapeutic potential of stem cells in heart disease

Coronary heart disease and chronic heart failure are common and have an increasing frequency. Although interventional and conventional drug therapy may delay ventricular remodelling, there is no basic therapeutic regime available for preventing or even reversing this process. Chronic coronary artery disease and heart failure impairs quality of life and are associated with subsequent worsening of the cardiac pump function. Numerous studies within the past few years have been demonstrated, that the intracoronary stem cell therapy has to be considered as a safe therapeutic procedure in heart disease, when destroyed and/or compromised heart muscle must be regenerated. This kind of cell therapy with autologous bone marrow cells is completely justified ethically, except for the small numbers of patients with direct or indirect bone marrow disease (e.g. myeloma, leukaemic infiltration) in whom there would be lesions of mononuclear cells. Several preclinical as well as clinical trials have shown that transplantation of autologous bone marrow cells or precursor cells improved cardiac function after myocardial infarction and in chronic coronary heart disease. The age of infarction seems to be irrelevant to regenerative potency of stem cells, since stem cells therapy in old infarctions (many years old) is almost equally effective in comparison to previous infarcts. Further indications are non-ischemic cardiomyopathy (dilative cardiomyopathy) and heart failure due to hypertensive heart disease.

Spectroscopic THz near-field microscope

We demonstrate a scattering-type scanning near-field optical microscope (s-SNOM) with broadband THz illumination. A cantilevered W tip is used in tapping AFM mode. The direct scattering spectrum is obtained and optimized by asynchronous optical sampling (ASOPS), while near-field scattering is observed by using a space-domain delay stage and harmonic demodulation of the detector signal. True near-field interaction is determined from the approach behavior of the tip to Au samples. Scattering spectra of differently doped Si are presented.

Mott transition in VO2 revealed by infrared spectroscopy and nano-imaging

Electrons in correlated insulators are prevented from conducting by Coulomb repulsion between them. When an insulator-to-metal transition is induced in a correlated insulator by doping or heating, the resulting conducting state can be radically different from that characterized by free electrons in conventional metals. We report on the electronic properties of a prototypical correlated insulator vanadium dioxide in which the metallic state can be induced by increasing temperature. Scanning near-field infrared microscopy allows us to directly image nanoscale metallic puddles that appear at the onset of the insulator-to-metal transition. In combination with far-field infrared spectroscopy, the data reveal the Mott transition with divergent quasi-particle mass in the metallic puddles. The experimental approach used sets the stage for investigations of charge dynamics on the nanoscale in other inhomogeneous correlated electron systems.

Factors influencing spontaneous mobilization of CD34+ and CD133+ progenitor cells after myocardial infarction

BACKGROUND

Bone marrow-derived circulating progenitor cells (BM-CPCs) are mobilized into adult peripheral blood (PB) during acute myocardial infarction (AMI) and may contribute to the regeneration of infarcted myocardium. The purpose of the present study is to determine whether mobilization of BM-CPCs into PB depends on cardiovascular risk factors (CVRFs), age of patients, infarct associated inflammatory markers, and left ventricular function after AMI.

MATERIALS AND METHODS

Peripheral blood concentrations of CD34/45(+) and CD133/45(+) BM-CPCs were measured by flow cytometry in 44 patients after AMI and in 16 subjects with atypical chest pain acting as controls.

RESULTS

Mobilization of CD34/45(+) and CD133/45(+) BM-CPCs on day 1 after AMI showed significant negative correlation with age, the number of CVRFs, infarct size, creatine phosphokinase peak in bivariate as well as in multivariate analyses. We additionally found a positive correlation of CD34/45(+) and CD133/45(+) BM-CPCs mobilization on day 1 after AMI with global ejection fraction (EF) in bivariate analysis but could not confirm this in multivariate analysis. Elevated of C-reactive protein (CRP) and leukocyte levels on day 1 after AMI were significantly associated with decreased concentrations of CD34/45(+) BM-CPCs. The concentrations of CD34/45(+) and CD133/45(+) BM-CPCs significantly increased in AMI patients, with the peak on day 7 as compared to the control group.

CONCLUSIONS

The mobilization of CD34/45(+) and CD133/45(+) BM-CPCs into the PB depends on many factors, i.e. the number of CVRFs, age, infarct size and inflammatory markers of patients. Most importantly, the severity of the circulatory dysfunction and the amount of necrotic myocardial tissue are the main determinants. Moreover, this spontaneous mobilization of BM-CPCs may serve as a very important surrogate for infarct size as well as for global EF and it may determine the regenerative potency after AMI.

Erfolgreiche Therapie eines Patienten im therapieresistenten kardiogenen Schock mit intrakoronarer, autologer Knochenmarkstammzelltransplantation

HISTORY AND CLINICAL FINDINGS

A 64-year-old man with known coronary 3-vessel disease (CAD) who had sustained an anterior myocardial infarction 14 years ago was admitted with signs of acute left heart failure associated with another anterior myocardial infarction.

INVESTIGATIONS

The electrocardiogram (ECG) showed ST-segment elevation from V1 to V6. Creatine kinase, troponin I and lactate dehydrogenase levels were elevated.

DIAGNOSIS

Emergency cardiac catheterization revealed a coronary 3-vessel disease with severe stenosis in left anterior descending coronary artery (LAD). Left ventricular angiography demonstrated severe impairment of left ventricular contractile function with akinesia of the entire anterior wall of the left ventricle.

TREATMENT AND COURSE

Coronary angioplasty and stent implantations of the LAD were undertaken, but cardiogenic shock occurred requiring intubation, ventilation and intraaortic counterpulsation (IABP). It was possible to discontinue the latter after two days, but the cardiogenic shock persisted for six weeks, requiring increasing amounts of catecholamines and high inspiratory ventilation pressure (max Pinsp) and high positive end-expiratory wedge pressure (PCW). Nine days after autologous adult bone marrow derived stem cell injection into the right and left coronary artery, the left ventricular function gradually improved and the catecholamine amount gradually reduced. It was then possible to extubate the patient and transfer him to a general ward. Angiocardiography after one month demonstrated an increase of the ejection fraction from 17% to 28% and good coronary blood flow in the LAD.

CONCLUSIONS

Intracoronary transplantation of adult autologous bone-marrow stem cells achieved safe and efficacious regeneration of ischemic and infarcted myocardium. It can be assumed that myocardial repair was associated with the stem cell transplantation and/or cytokine action. The intracoronary stem cell transplantation may reduce the mortality of otherwise treatment-resistant cardiogenic shock.

Transplantation of autologous mononuclear bone marrow stem cells in patients with peripheral arterial disease (the TAM-PAD study)

OBJECTIVES

For patients with severe, chronic limb ischemia in many cases interventional or surgical treatment is not possible anymore. In the past, both intramuscular and intraarterial transplantation of autologous BMCs had been proved therapeutically beneficial. The TAM-PAD study is the first one to analyze combined intraarterial and intramuscular BMC transplantation in its acute and long-term effects.

METHODS

13 patients with chronically ischemic limbs due to peripheral arterial disease (Fontaine stage IIb) were recruited and underwent follow-up examinations after 2 and 13 months. Mononuclear cells from bone marrow were injected intramuscular and intraarterial into the ischemic limb.

RESULTS

In contrast to the control group, after 2 months the pain-free walking distance of the transplanted patients significantly increased (from 147 +/- 90 to 500 +/- 614 m, p = 0.001). Furthermore the ankle-brachial index was significantly improved (at rest from 0.66+/-0.18 to 0.80+/-0.15, p = 0.003, after stress from 0.64 +/- 0.19 to 0.76 +/- 0.16, p = 0.006). Similar improvement was documented in capillary-venous oxygen-saturation (thigh from 59 +/- 9 to 66 +/- 5, p = 0.005, lower leg from 56 +/- 14 to 63 +/- 5, p = 0.021) and venous occlusion plethysmography (rest from 2.1 +/- 0.7 to 2.5 +/- 0.7, p = 0.009, mean reactive hyperemia from 5.3 +/- 1.8 to 7.2 +/- 1.8, p = 0.003, and peak flow from 7.2 +/- 3.2 to 10.8 +/- 2.8, p = 0.002). After 13 months these positive effects persisted at their improved level. No side effects or complications were monitored.

CONCLUSIONS

Combined intraarterial and intramuscular transplantation of autologous mononuclear bone marrow stem cells is a clinically feasible and minimally invasive therapeutic option for patients with severe chronic peripheral occlusive arterial disease.

Goose-mediated nutrient enrichment and planktonic grazer control in arctic freshwater ponds

A dramatic increase in the breeding population of geese has occurred over the past few decades at Svalbard. This may strongly impact the fragile ecosystems of the Arctic tundra because many of the ultra-oligotrophic freshwater systems experience enrichment from goose feces. We surveyed 21 shallow tundra ponds along a gradient of nutrient enrichment based on exposure to geese. Concentrations of total phosphorus (P) and dissolved inorganic nitrogen (DIN) in the tundra ponds ranged from 2-76 to 2-23 microg l(-1) respectively, yet there was no significant increase in phytoplankton biomass (measured as chlorophyll a; range: 0.6-7.3 microg l(-1)) along the nutrient gradient. This lack of response may be the result of the trophic structure of these ecosystems, which consists of only a two-trophic level food chain with high biomasses of the efficient zooplankton grazer Daphnia in the absence of fish and scarcity of invertebrate predators. Our results indicate that this may cause a highly efficient grazing control of phytoplankton in all ponds, supported by the fact that large fractions of the nutrient pools were bound in zooplankton biomass. The median percentage of Daphnia-N and Daphnia-P content to particulate (sestonic) N and P was 338 and 3009%, respectively, which is extremely high compared to temperate lakes. Our data suggest that Daphnia in shallow arctic ponds is heavily subsidized by major inputs of energy from other food sources (bacteria, benthic biofilm), which may be crucial to the persistence of strong top-down control of pelagic algae by Daphnia.

Increased cardiac mRNA expression of matrix metalloproteinase-1 (MMP-1) and its inhibitor (TIMP-1) in DCM patients

Left ventricular dilation and myocardial remodeling are hallmarks of dilated cardiomyopathy (DCM). It is assumed that left ventricular dilation is caused by the disintegration of the collagenous network by increased collagenolytic activity of matrix metalloproteinases (MMPs) and their adequate tissue inhibitors (TIMPs). In this study the myocardial MMP-1 and TIMP-1 mRNA expressions were investigated by using real-time quantitative PCR analysis from right septal endomyocardial biopsies of patients with dilated cardiomyopathy (n = 46) and control subjects (n = 11). The volume density (Vv%) of collagen was measured morphometrically. Classification was done according to LV diameters [left ventricular enddiastolic diameter (LVEDD, cm) calculated to body surface area (BSA, m(2))] into three DCM groups: group I (LVEDD-BSA > 2.7-3.0 cm/m(2)), group II ( > 3.0-3.6 cm/m(2)), group III ( > 3.6 cm/m(2)), controls (< 2.7 cm/m(2)). Compared with controls, the MMP-1 expression in patients with DCM was significantly increased (119.2 +/- 45.2 vs. 1.3 +/- 0.4; p < 0.001) as was TIMP-1 expression (9.6 +/- 1.2 vs. 1.3 +/- 0.4; p < 0.01). Moreover the MMP-1 and TIMP-1 expression varied according to LV diameter: group I (MMP-1: 8.7 +/- 3.5; p = 0.33; TIMP- 1: 4.5 +/- 1.2; p < 0.01); group II (MMP-1: 211.4 +/- 86.0; p < 0.001; TIMP-1: 12.5 +/- 1.9 ; p < 0.001); group III (MMP-1: 38.8 +/- 22.6; p < 0.01; TIMP-1: 8.1 +/- 1.7; p < 0.001). Compared with controls, the collagen level in DCMPt. was significantly increased: 5.0 +/- 0.6 vol% vs 1.2 +/- 0.2 vol% p < 0.001 and correlates with LV diameter. This study reveals that the overexpression of MMP-1, which is associated with an increased ratio of MMP-1/TIMP-1 in DCM, indicates an activated collagenolytic system while replacement fibrosis is accumulating. The MMP-1 overexpression is mainly found in moderately dilated DCM hearts (group II) indicating the dynamic process of LV dilation and the importance of collagenases in the early phase of LV remodeling.

Intraarterielle und intramuskuläre Transplantation adulter, autologer Knochenmarkstammzellen

HISTORY AND CLINICAL FINDINGS

A 62-year-old man had limb ischemia in stage IIb (Fontaine's classification). After surgical and interventional measures the right superficial femoral artery had remained occluded for more than one year. The patient's walking distance was only 100 meters. It was therefore decided to do a combined intraarterial and intramuscular transplantation of stem cells into the right limb.

INVESTIGATIONS

Before and 10 weeks after the transplantation noninvasive tests, namely walking distance, ankle-brachial index at rest and during exercise, occlusion plethysmography and capillary venous oxygen saturation were measured. The patient was also asked to fill in a questionnaire of his symptoms.

THERAPY AND RESULTS

After harvesting the patient's bone marrow the mononuclear cell fraction was separated (109.8 x 10(6)). Afterwards 10 ml of the cell suspension were injected into the right superficial femoral artery and 5 ml each of the suspension was injected into 5 different locations of the quadriceps femoris and the gastrocnemius muscles. After 10 weeks" follow-up a seven-fold improvement of walking distance and an increase of tissue oxygen saturation of more then 50% were recorded. The ankle-brachial index at rest remained unchanged, but on exercise it increased by 24%.

CONCLUSION

The combined intraarterial and intramuscular transplantation of human autologous bone marrow stem cells may be a novel and clinically feasible treatment for patients with severe chronic limb ischemia. The success of this approach may be the result of increased neo-angiogenesis, especially of the small muscle-supplying vessels.

Comparing grazing on lake seston by Dreissena and Daphnia: lessons for biomanipulation

Biomanipulation measures in lakes, taken to diminish algal blooms, have mainly been restricted to the reduction of zooplanktivorous fish with the aim to stimulate the grazing pressure by native filter feeders such as Daphnia. However, larger filter feeders like the exotic zebra mussel, Dreissena polymorpha, have been suggested as an optional tool because of their high filtering capacity. We compared grazing by two filter feeders, D. polymorpha and Daphnia galeata, offered seston from Lake IJsselmeer, the Netherlands in two consecutive years: 2002 and 2003. The seston in both years was dominated by the colony-forming cyanobacterium Microcystis aeruginosa. The grazing studies were performed under controlled conditions in the laboratory and samples were analyzed on a flow cytometer, making it possible to quantify grazing on different seston components and size fractions, including cyanobacteria, other phytoplankton (green algae, diatoms, etc.), and detritus. No differences in clearance rates, on a per weight basis, were found between the two grazer species. The clearance rate on cyanobacteria (especially <20 microm) was lower in 2003 than in 2002. In 2003, the microcystin concentration of cyanobacteria was higher than in 2002, suggesting that the observed lower clearance rate in 2003 was due to the enhanced toxin content of the cyanobacteria. Zebra mussels, although indiscriminately filtering all seston groups out of the water, positively selected for phytoplankton in their mantle cavity, irrespective of its toxicity, and rejected detritus. Since no differences in clearance rates were found between the two grazer species, we conclude that for biomanipulation purposes of shallow lakes, native species like the daphnids should be preferred over exotic species like zebra mussels. When the seston is dominated by phytoplankton that cannot be filtered out of the water column by Daphnia, however, the use of zebra mussels may be considered. Care should be taken, however, in the choice of the lakes since the mussels may have severe ecological and economic impacts.

Full-genome RNAi profiling of early embryogenesis in Caenorhabditis elegans

A key challenge of functional genomics today is to generate well-annotated data sets that can be interpreted across different platforms and technologies. Large-scale functional genomics data often fail to connect to standard experimental approaches of gene characterization in individual laboratories. Furthermore, a lack of universal annotation standards for phenotypic data sets makes it difficult to compare different screening approaches. Here we address this problem in a screen designed to identify all genes required for the first two rounds of cell division in the Caenorhabditis elegans embryo. We used RNA-mediated interference to target 98% of all genes predicted in the C. elegans genome in combination with differential interference contrast time-lapse microscopy. Through systematic annotation of the resulting movies, we developed a phenotypic profiling system, which shows high correlation with cellular processes and biochemical pathways, thus enabling us to predict new functions for previously uncharacterized genes.

[Potentials and limitations of stem cell therapy in myocardial disease]

Acute myocardial infarction (MI) leads to myocardial necrosis and is, by nature, an irreversible injury. The major goal to reverse left ventricular remodeling would be the enhancement of regeneration of cardiac myocytes as well as the stimulation of neovascularization within the infarct area, by repopulation of the injured myocardium with healthy autologous cells. In March 2001, the first patient was treated with direct intracoronary administration of autologous mononuclear bone marrow cells after acute MI. As improvements in myocardial function and perfusion could be detected 3 months later without any complications - a study was initiated in Düsseldorf. Until now 40 patients have been investigated. After a three month follow-up period, significant improvements concerning myocardial function, perfusion and metabolism could be obtained. This therapeutical effect may be attributed to bone marrow cell-associated myocardial regeneration and neovascularization. These results demonstrate that functional and metabolic regeneration of infarcted myocardium can be safely realized in humans by bone marrow mononuclear cell transplantation.

[ Update 2001. Myocarditis--cardiomyopathy]

Myocarditis is a common cardiological disease. New molecular biological and immunohistological methods have confirmed the persistence of viral infection and chronic myocardial inflammation in a considerable number of patients. A causal link between viral myocarditis and the development of dilated cardiomyopathy has been recognized. This has prognostic implications and helps for the decision of a specific immunosuppressive, immunomodulatory and antiviral therapy.

[Intracoronary, human autologous stem cell transplantation for myocardial regeneration following myocardial infarction]

OBJECTIVE

The regenerative potential of human autologous adult stem cells on myocardial regeneration and neovascularisation after myocardial infarction may contribute to healing of the infarction area. But no clinical application has previously been reported. We here describe for the first time the results of this method applied in a patient who had sustained an acute myocardial infarction.

HISTORY AND CLINICAL FINDINGS

14 hours after the onset of left precordial pain a 46-year-old man was admitted to our hospital for interventional diagnosis and treatment. Coronary angiography demonstrated occlusion of the anterior descending branch of the left coronary artery with transmural infarction. This was treated by percutaneous transluminal catheter angioplasty and stent placement.

THERAPY AND RESULTS

Mononuclear bone marrow cells of the patient were prepared and 6 days after infaction 1,2 infinity 107 cells were transplanted at low pressure via a percutaneous transluminal catheter placed in the infarct-related artery. Before and 10 weeks after this procedure left ventricular function, infarct size, ventricular geometry and myocardial perfusion were measured by (201)thallium SPECT both at rest and on exercise, together with bull's-eye analysis, dobutamine stress echocardiography, right heart catheterisation and radionuclide ventriculography. At 10 weeks after the stem cell transplantation the transmural infarct area had been reduced from 24.6 % to 15.7 % of left ventricular circumference, while ejection fraction, cardiac index and stroke volume had increased by 20-30 %. On exercise the end diastolic volume had decreased by 30 % and there was a comparable fall in left ventricular filling pressure (mean pulmonary capillary pressure).

CONCLUSION

These results for the first time demonstrate that selective intracoronary transplantation of human autologous adult stem cells is possible under clinical conditions and that it can lead to regeneration of the myocardial scar after transmural infarction. The therapeutic effects may be ascribed to stem cell-associated myocardial regeneration and neovascularisation.

Functional genomic analysis of cell division in C. elegans using RNAi of genes on chromosome III

Genome sequencing projects generate a wealth of information; however, the ultimate goal of such projects is to accelerate the identification of the biological function of genes. This creates a need for comprehensive studies to fill the gap between sequence and function. Here we report the results of a functional genomic screen to identify genes required for cell division in Caenorhabditis elegans. We inhibited the expression of approximately 96% of the approximately 2,300 predicted open reading frames on chromosome III using RNA-mediated interference (RNAi). By using an in vivo time-lapse differential interference contrast microscopy assay, we identified 133 genes (approximately 6%) necessary for distinct cellular processes in early embryos. Our results indicate that these genes represent most of the genes on chromosome III that are required for proper cell division in C. elegans embryos. The complete data set, including sample time-lapse recordings, has been deposited in an open access database. We found that approximately 47% of the genes associated with a differential interference contrast phenotype have clear orthologues in other eukaryotes, indicating that this screen provides putative gene functions for other species as well.

Repair of coronary arterioles after treatment with perindopril in hypertensive heart disease

In hypertensive heart disease, no data are available on the repair of coronary resistance vessels in patients after long-term ACE inhibitor treatment. Fourteen patients with essential hypertension were studied with coronary flow reserve and with transvenous endomyocardial biopsy before and after 12 months of antihypertensive treatment with perindopril (4 to 8 mg/d, mean 5.9+/-2.3 mg/d). Left ventricular muscle mass index decreased by 11% (from 145+/-41 to 128+/-36 g/m(2), P=0.04). Maximal coronary blood flow was increased by 54% (from 170+/-46 to 263+/-142 mL. min(-1). 100 g(-1), P=0.001), and minimal coronary vascular resistance was diminished by 33% (from 0.67+/-0.21 to 0.45+/-0.19 mm Hg. min. 100 g. mL(-1), P=0.001); consequently, coronary reserve increased by 67% from 2.1+/-0.6 to 3. 5+/-1.9 (P=0.001). Structural analysis revealed regression of periarteriolar collagen area by 54% (from 558+/-270 to 260+/-173 microm(2), P=0.04) and of total interstitial collagen volume density by 22% (from 5.5+/-3.8 Vv% to 4.3+/-3.2 Vv%, P=0.04), whereas arteriolar wall area was slightly but not significantly reduced. Long-term therapy with the ACE inhibitor perindopril induces structural repair of coronary arterioles that is mainly characterized by the regression of periarteriolar fibrosis and associated with a marked improvement in coronary reserve. These findings indicate the beneficial reparative effects of ACE inhibition on coronary microcirculation in hypertensive heart disease.

Activated Borna disease virus in affective disorders

BACKGROUND

Borna disease virus (BDV) is an animal pathogen that causes behavioral changes in animals. Previous studies have found a high prevalence of serum antibodies as well as Borna disease viral antigens (BDVAGs) and RNA in the white blood cells of psychiatric patients, especially those with affective disorders. The present study attempts to offer a better description of the BDVAG cohort using clinical parameters.

METHODS

The prevalence of BDVAG was examined in the peripheral mononuclear leukocytes of patients with a major depressive episode. A subgroup of patients underwent further clinical analysis.

RESULTS

In this pilot study, at least, there was a significant difference in the prevalence of BDVAG between psychiatric inpatients with a major depressive episode and control individuals. It also appeared that BDVAG is more frequent in patients with recurrent major depression or bipolar disorder than in those with any other psychiatric disorder studied. The number of previous depressive episodes, as well as symptoms involving fatigue and concentration difficulties were positively related to BDVAG.

CONCLUSIONS

The high rate of BDVAG, especially in fatigued patients with recurrent major depression or bipolar disorder, may be a nonspecific aspect of immunosuppression. The question remains whether this neurotropic virus may contribute to the pathogenesis of some types of affective disorder.

Immunogenicity of herpes simplex virus type 1 mutants containing deletions in one or more alpha-genes: ICP4, ICP27, ICP22, and ICP0

Replication defective mutants of HSV have been proposed both as vaccine candidates and as vehicles for gene therapy because of their inability to produce infectious progeny. The immunogenicity of these HSV replication mutants, at both qualitative and quantitative levels, will directly determine their effectiveness for either of these applications. We have previously reported (Brehm et al., J. Virol., 71, 3534, 1997) that a replication defective mutant of HSV-1, which expresses a substantial level of viral genes without producing virus particles, is as efficient as wild-type HSV-1 in eliciting an HSV-specific cytotoxic T-lymphocyte (CTL) response. In this report, we have further evaluated the immunogenic potential of HSV-1-derived replication defective mutants by examining the generation of HSV-specific CTL following immunization with viruses that are severely restricted in viral gene expression due to mutations in one or more HSV alpha genes (ICP4, ICP27, ICP22, and ICP0). To measure the CTL responses induced by the HSV alpha-mutants, we have targeted two H-2Kb-restricted CTL epitopes: an epitope in a virion protein, gB (498-505), and an epitope in a nonvirion protein, ribonucleotide reductase (RR1 822-829). The HSV mutants used in this study are impaired in their ability to express gB while a majority of them still express RR1. Our findings demonstrate that a single immunization with these mutants is able to generate a strong CTL response not only to RR1 822-829, but also to gB498-505 despite their inability to express wild-type levels of gB. Furthermore, a single immunization with any individual mutant can also provide immune protection against HSV challenge. These results suggest that mutants which are restricted in gene expression may be used as effective immunogens in vivo.

Synthesis and Physicochemical Characterization of a New Gadolinium Chelate: The Liver-Specific Magnetic Resonance Imaging Contrast Agent Gd-EOB-DTPA

A convenient synthesis of disodium S-[4-(4-ethoxybenzyl)-3,6,9-tris[(carboxy-kappaO)methyl]-3,6,9-triazaundecandioato)(5-)-kappa(3)N(3)(),N(6)(),N(9)(),kappa(2)O(1)(),O(11)()]gadolinate(2-) (Gd-EOB-DTPA), 1, is reported. This water-soluble complex is presently undergoing phase III clinical trials as a liver-specific contrast agent for magnetic resonance imaging (MRI). The thermodynamic complex stability constant of 1 and the acid dissociation constants of the ligand have been determined as well as the stability constant of the calcium complex Ca-EOB-DTPA (2), which is used as an additive in the pharmaceutical formulation of the contrast agent. The solid-state structure of the ligand S-4-(4-ethoxybenzyl)-3,6,9-tris(carboxylatomethyl)-3,6,9-triazaundecanedioic acid (H(5)EOB-DTPA), 3, has been elucidated in a single crystal X-ray diffraction study. Additionally, HPLC evidence is given that the enantiomerically pure ligand forms two diastereomeric gadolinium complexes in a 65:35 ratio. The kinetics of isomerization of the isolated diastereomers-as dependent on pH and temperature-has been investigated, and thus, the activation energy for the interconversion of these isomers has been estimated to be 75.3 kJ mol(-1). Finally, the structures of the two components of 1 are discussed in terms of four possible diastereomers.

A molecular basis for how a single TCR interfaces multiple ligands

CD8+ T cells respond to Ags when their clonotypic receptor, the TCR, recognizes nonself peptides displayed by MHC class I molecules. The TCR/ligand interactions are degenerate because, in its life time, the TCR interacts with self MHC class I-self peptide complexes during ontogeny and with self class I complexed with nonself peptides to initiate Ag-specific responses. Additionally, the same TCR has the potential to interact with nonself class I complexed with nonself peptides. How a single TCR interfaces multiple ligands remains unclear. Combinatorial synthetic peptide libraries provide a powerful tool to elucidate the rules that dictate how a single TCR engages multiple ligands. Such libraries were used to probe the requirements for TCR recognition by cloned CD8+ T cells directed against Ags presented by H-2Kb class I molecules. When H-2Kb contact residues were examined, position 3 of the peptides proved more critical than the dominant carboxyl-terminal anchor residue. Thus, secondary anchor residues can play a dominant role in determining the antigenicity of the epitope presented by class I molecules. When the four solvent-exposed potential TCR contact residues were examined, only one or two of these positions required structurally similar residues. Considerable structural variability was tolerated at the remaining two or three solvent-exposed residues of the Kb-binding peptides. The TCR, therefore, requires close physico-chemical complementarity with only a few amino acid residues, thus explaining why TCR/MHC interactions are of low affinity and degenerate.