Combinatorial G-CSF/AMD3100 Treatment in Cardiac Repair after Myocardial Infarction

Aims

Several studies suggest that circulating bone marrow derived stem cells promote the regeneration of ischemic tissues. For hematopoietic stem cell transplantation combinatorial granulocyte-colony stimulating factor (G-CSF)/Plerixafor (AMD3100) administration was shown to enhance mobilization of bone marrow derived stem cells compared to G-CSF monotherapy. Here we tested the hypothesis whether combinatorial G-CSF/AMD3100 therapy has beneficial effects in cardiac recovery in a mouse model of myocardial infarction.

Methods

We analyzed the effect of single G-CSF (250 µg/kg/day) and combinatorial G-CSF/AMD3100 (100 µg/kg/day) treatment on cardiac morphology, vascularization, and hemodynamics 28 days after permanent ligation of the left anterior descending artery (LAD). G-CSF treatment started directly after induction of myocardial infarction (MI) for 3 consecutive days followed by a single AMD3100 application on day three after MI in the G-CSF/AMD3100 group. Cell mobilization was assessed by flow cytometry of blood samples drawn from tail vein on day 0, 7, and 14.

Results

Peripheral blood analysis 7 days after MI showed enhanced mobilization of white blood cells (WBC) and endothelial progenitor cells (EPC) upon G-CSF and combinatorial G-CSF/AMD3100 treatment. However, single or combinatorial treatment showed no improvement in survival, left ventricular function, and infarction size compared to the saline treated control group 28 days after MI. Furthermore, no differences in histology and vascularization of infarcted hearts could be observed.

Conclusion

Although the implemented treatment regimen caused no adverse effects, our data show that combinatorial G-CSF/AMD therapy does not promote myocardial regeneration after permanent LAD occlusion.     

Identification of a Potent Endothelium-Derived Angiogenic Factor

The secretion of angiogenic factors by vascular endothelial cells is one of the key mechanisms of angiogenesis. Here we report on the isolation of a new potent angiogenic factor, diuridine tetraphosphate (Up₄U) from the secretome of human endothelial cells. The angiogenic effect of the endothelial secretome was partially reduced after incubation with alkaline phosphatase and abolished in the presence of suramin. In one fraction, purified to homogeneity by reversed phase and affinity chromatography, Up₄U was identified by MALDI-LIFT-fragment-mass-spectrometry, enzymatic cleavage analysis and retention-time comparison. Beside a strong angiogenic effect on the yolk sac membrane and the developing rat embryo itself, Up₄U increased the proliferation rate of endothelial cells and, in the presence of PDGF, of vascular smooth muscle cells. Up₄U stimulated the migration rate of endothelial cells via P2Y2-receptors, increased the ability of endothelial cells to form capillary-like tubes and acts as a potent inducer of sprouting angiogenesis originating from gel-embedded EC spheroids. Endothelial cells released Up₄U after stimulation with shear stress. Mean total plasma Up₄U concentrations of healthy subjects (N = 6) were sufficient to induce angiogenic and proliferative effects (1.34±0.26 nmol L^-1). In conclusion, Up₄U is a novel strong human endothelium-derived angiogenic factor.     

The Burden of Research on Trauma for Respondents: A Prospective and Comparative Study on Respondents Evaluations and Predictors

The possible burden of participating in trauma research is an important topic for Ethical Committees (EC''s), Review Boards (RB''s) and researchers. However, to what extent research on trauma is more burdensome than non-trauma research is unknown. Little is known about which factors explain respondents evaluations on the burden: to what extent are they trauma-related or dependent on other factors such as personality and how respondents evaluate research in general? Data of a large probability based multi-wave internet panel, with surveys on politics and values, personality and health in 2009 and 2011, and a survey on trauma in 2012 provided the unique opportunity to address these questions. Results among respondents confronted with these events in the past 2 years (N = 950) showed that questions on trauma were significantly and systematically evaluated as less pleasant (enjoyed less), more difficult, but also stimulated respondents to think about things more than almost all previous non-trauma surveys. Yet, the computed effect sizes indicated that the differences were (very) small and often meaningless. No differences were found between users and non-users of mental services, in contrast to posttraumatic stress symptoms. Evaluations of the burden of previous surveys in 2011 on politics and values, personality and health most strongly, systematically and independently predicted the burden of questions on trauma, and not posttraumatic stress symptoms, event-related coping self-efficacy and personality factors. For instance, multiple linear regression analyses showed that 30% of the variance of how (un)pleasant questions on trauma and life-events were evaluated, was explained by how (un)pleasant the 3 surveys in 2011 were evaluated, in contrast to posttraumatic stress symptoms (not significant) and coping self-efficacy (5%). Findings question why EC''s, RB''s and researchers should be more critical of the possible burden of trauma research than of the possible burden of other non-trauma research.     

Four distinct chondrocyte populations in the fetal bovine growth plate: highest expression levels of PTH/PTHrP receptor,Indian hedgehog,and MMP-13 in hypertrophic chondrocytes and their suppression by PTH (1-34) and PTHrP (1-40)

Differentiation and growth of chondrocytes in fetal growth plates of vertebrate long bones and ribs appear to occur in a gradual, continuous manner between the resting zone through the proliferation zone, maturation zone, and upper and lower hypertrophic zones, with a continuous increase in cell size up to 10-fold of the volume of a resting chondrocyte. Here we provide evidence, however, that after centrifugation through a continuous Percoll gradient growth plate chondrocytes separate into four distinct cell populations (B1 to B4) which differ markedly in density, size, and gene expression. These populations collect in the absence of any phase borders in the gradient which might serve as concentration barriers. Fractions B1 and B2 contained the largest cells with the lowest buoyant density and showed the highest expression levels for type X collagen (Col X), but only the B1 population expressed high levels of matrix metalloproteinase-13 (collagenase 3). Cells in fraction B3 were significantly smaller and expressed little Col X, while cells in fraction B4 were of similar size to cells in the resting zone without significant Col X expression. The highest levels of parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor (PTHR-1), and Indian hedgehog (Ihh) expression were also found in the hypertrophic fractions B1 and B2 and not in the prehypertrophic fraction B3, as expected from in situ hybridization data on PTHR-1 expression in fetal rodent or chicken growth plates. Incubation of fractions B1 to B3 with the amino-terminal fragments PTH (1-34) or PTHrP (1-40) suppressed the expression of Col X and PTHR-1 by more than 50% and the expression of Ihh nearly completely. In contrast, the mid-regional PTH fragment PTH (28-48) and PTH (52-84) consistently stimulated the expression of PTHR-1 by 10-20% in fractions B1 to B3. These findings confirm the existence of distinct differentiation stages within chondrocytes of the growth plate and support the hypothesis proposed by Vortkamp et al. (Science 273(1996)613) of a regulatory feedback loop of Ihh and PTH/PTHrP fragments controlling the differentiation of proliferating to prehypertrophic chondrocytes, but extend the ability to respond to PTH/PTHrP hypertrophic chondrocytes.     

Analysis of spiking synchrony in visual cortex reveals distinct types of top-down modulation signals for spatial and object-based attention

The activity of a border ownership selective (BOS) neuron indicates where a foreground object is located relative to its (classical) receptive field (RF). A population of BOS neurons thus provides an important component of perceptual grouping, the organization of the visual scene into objects. In previous theoretical work, it has been suggested that this grouping mechanism is implemented by a population of dedicated grouping (“G”) cells that integrate the activity of the distributed feature cells representing an object and, by feedback, modulate the same cells, thus making them border ownership selective. The feedback modulation by G cells is thought to also provide the mechanism for object-based attention. A recent modeling study showed that modulatory common feedback, implemented by synapses with N-methyl-D-aspartate (NMDA)-type glutamate receptors, accounts for the experimentally observed synchrony in spike trains of BOS neurons and the shape of cross-correlations between them, including its dependence on the attentional state. However, that study was limited to pairs of BOS neurons with consistent border ownership preferences, defined as two neurons tuned to respond to the same visual object, in which attention decreases synchrony. But attention has also been shown to increase synchrony in neurons with inconsistent border ownership selectivity. Here we extend the computational model from the previous study to fully understand these effects of attention. We postulate the existence of a second type of G-cell that represents spatial attention by modulating the activity of all BOS cells in a spatially defined area. Simulations of this model show that a combination of spatial and object-based mechanisms fully accounts for the observed pattern of synchrony between BOS neurons. Our results suggest that modulatory feedback from G-cells may underlie both spatial and object-based attention.     

Effects of aerobic exercise therapy and cognitive behavioural therapy on functioning and quality of life in amyotrophic lateral sclerosis: protocol of the FACTS-2-ALS trial

Background

Neuropathic pain must be correctly diagnosed for optimal treatment. The questionnaire named Neuropathic Pain Symptom Inventory (NPSI) was developed in its original French version to evaluate the different symptoms of neuropathic pain. We hypothesized that the NPSI might also be used to differentiate neuropathic from non-neuropathic pain.

Methods

We translated the NPSI into German using a standard forward-backward translation and administered it in a case-control design to patients with neuropathic (n = 68) and non-neuropathic pain (headache and osteoarthritis, n = 169) to validate it and to analyze its discriminant properties, its sensitivity to change, and to detect neuropathic pain subgroups with distinct profiles.

Results

Using a sum score (the NPSI-G score), we found sensitivity to change (r between 0.37 and 0.5 for pain items of the graded chronic pain scale) and could distinguish between neuropathic and other pain on a group basis, but not for individual patients. Post hoc development of a discriminant score with optimized diagnostic properties to distinguish neuropathic pain from non-neuropathic pain resulted in an instrument with high sensitivity (91%) and acceptable specificity (70%). We detected six different pain profiles in the patient group with neuropathic pain; three profiles were found to be distinct.

Conclusions

The NPSI-G potentially combines the properties of a diagnostic tool and an instrument to identify subtypes of neuropathic pain.     

A 2nd Generation Linkage Map of Heterobasidion annosum s.l. Based on In Silico Anchoring of AFLP Markers

In this study, we present a 2^nd generation genetic linkage map of a cross between the North American species Heterobasidion irregulare and H. occidentale, based on the alignment of the previously published 1^st generation map to the parental genomes. We anchored 216 of the original 308 AFLP markers to their respective restriction sites using an in silico-approach. The map resolution was improved by adding 146 sequence-tagged microsatellite markers and 39 sequenced gene markers. The new markers confirmed the positions of the anchored AFLP markers, fused the original 39 linkage groups together into 17, and fully expanded 12 of these to single groups covering entire chromosomes. Map coverage of the genome increased from 55.3% to 92.8%, with 96.3% of 430 markers collinearly aligned with the genome sequence. The anchored map also improved the H. irregulare assembly considerably. It identified several errors in scaffold arrangements and assisted in reducing the total number of major scaffolds from 18 to 15. This denser, more comprehensive map allowed sequence-based mapping of three intersterility loci and one mating type locus. This demonstrates the possibility to utilize an in silico procedure to convert anonymous markers into sequence-tagged ones, as well as the power of a sequence-anchored linkage map and its usefulness in the assembly of a whole genome sequence.