Publications by authors named "Ildiko Racz"

72 Publications

Systemic inflammation induced the delayed reduction of excitatory synapses in the CA3 during ageing.

J Neurochem 2021 Aug 11. Epub 2021 Aug 11.

Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Bonn, Germany.

Sepsis-associated encephalopathy (SAE) represents diverse cerebral dysfunctions in response to pathogen-induced systemic inflammation. Peripheral exposure to lipopolysaccharide (LPS), a component of the gram-negative bacterial cell wall, has been extensively used to model systemic inflammation. Our previous studies suggested that LPS led to hippocampal neuron death and synaptic destruction in vivo. However, the underlying roles of activated microglia in these neuronal changes remained unclear. Here, LPS from two different bacterial strains (Salmonella enterica or E. coli) were compared and injected in 14- to 16-month-old mice and evaluated for neuroinflammation and neuronal integrity in the hippocampus at 7 or 63 days post-injection (dpi). LPS injection resulted in persistent neuroinflammation lasting for seven days and a subsequent normalisation by 63 dpi. Of note, increases in proinflammatory cytokines, microglial morphology and microglial mean lysosome volume were more pronounced after E. coli LPS injection than Salmonella LPS at 7 dpi. While inhibitory synaptic puncta density remained normal, excitatory synaptic puncta were locally reduced in the CA3 region of the hippocampus at 63 dpi. Finally, we provide evidence that excitatory synapses coated with complement factor 3 (C3) decreased between 7 dpi and 63 dpi. Although we did not find an increase of synaptic pruning by microglia, it is plausible that microglia recognised and eliminated these C3-tagged synapses between the two time points of investigation. Since a region-specific decline of CA3 synapses has previously been reported during normal ageing, we postulate that systemic inflammation may have accelerated or worsened the CA3 synaptic changes in the ageing brain.
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http://dx.doi.org/10.1111/jnc.15491DOI Listing
August 2021

Predictors of Hospital Mortality in Patients with Acute Coronary Syndrome Complicated by Cardiogenic Shock.

Sensors (Basel) 2021 Feb 1;21(3). Epub 2021 Feb 1.

Department of Cardiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary.

As demonstrated by earlier studies, pre-hospital triage with trans-telephonic electrocardiogram (TTECG) and direct referral for catheter therapy shows great value in the management of out-of-hospital chest pain emergencies. It does not only improve in-hospital mortality in ST-segment elevation myocardial infarction, but it has also been identified as an independent predictor of higher in-hospital survival rate. Since TTECG-facilitated triage shortens both transport time and percutaneous coronary intervention (PCI)-related procedural time intervals, it was hypothesized that even high-risk patients with acute coronary syndrome (ACS) and cardiogenic shock (CS) might also benefit from TTECG-based triage. Here, we decided to examine our database for new triage- and left ventricular (LV) function-related parameters that can influence in-hospital mortality in ACS complicated by CS. ACS patients were divided into two groups, namely, (1) hospital death patients ( = 77), and (2) hospital survivors (control, = 210). Interestingly, TTECG-based consultation and triage of CS and ACS patients were confirmed as significant independent predictors of lower hospital mortality risk (odds ratio (OR) 0.40, confidence interval (CI) 0.21-0.76, = 0.0049). Regarding LV function and blood chemistry, a good myocardial reperfusion after PCI (high area at risk (AAR) blush score/AAR LV segment number; OR 0.85, CI 0.78-0.98, = 0.0178) and high glomerular filtration rate (GFR) value at the time of hospital admission (OR 0.97, CI 0.96-0.99, = 0.0042) were the most crucial independent predictors of a decreased risk of in-hospital mortality in this model. At the same time, a prolonged time interval between symptom onset and hospital admission, successful resuscitation, and higher peak creatine kinase activity were the most important independent predictors for an increased risk of in-hospital mortality. In ACS patients with CS, (1) an early TTECG-based teleconsultation and triage, as well as (2) good myocardial perfusion after PCI and a high GFR value at the time of hospital admission, appear as major independent predictors of a lower in-hospital mortality rate.
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http://dx.doi.org/10.3390/s21030969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7867036PMC
February 2021

Level of the SARS-CoV-2 receptor ACE2 activity is highly elevated in old-aged patients with aortic stenosis: implications for ACE2 as a biomarker for the severity of COVID-19.

Geroscience 2021 02 20;43(1):19-29. Epub 2021 Jan 20.

Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.

Coronavirus disease 2019 (COVID-19) has a high mortality in elderly patients with pre-existing cardiovascular diseases. The cellular receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the angiotensin-converting enzyme 2 (ACE2), thereby implicating a link between cardiovascular diseases and SARS-CoV-2 susceptibility. Aortic stenosis (AS) represents a chronic inflammatory state with severe cardiovascular complications in the elderly, a prime condition for COVID-19 mortality. The circulating ACE2 levels were measured in 111 patients with severe AS and compared to patients with hypertension and healthy individuals. About 4 times higher circulating ACE2 activity was found in patients with severe AS than in hypertensives or healthy individuals (88.3 ± 61.6., n = 111, 20.6 ± 13.4, n = 540, and 16.1 ± 7.4 mU/L, n = 46, respectively). Patients with severe AS were older than patients with hypertension (80 ± 6 years vs. 60 ± 15 years, P < 0.05). Serum ACE2 activity correlated negatively with the left ventricular ejection fraction, aortic root area, TAPSE, and positively with the right ventricular systolic pressure, cardiac diameters in patients with AS. In contrast, circulating ACE2 activity was independent of the blood pressure, peak flow velocity at the aortic root, kidney function (GFR), and inflammatory state (CRP). We found no effect of RAAS inhibitory drugs on the serum ACE2 activity in this group of patients. Our results illustrate circulating ACE2 as a potential interface between chronic inflammation, cardiovascular disease, and COVID-19 susceptibility. Elderly patients with AS have markedly elevated ACE2 levels together with altered left and right ventricular functions, which may pose higher risks during COVID-19. Our clinical data do not support a role for RAAS inhibitors in regulating circulating ACE2 levels.
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http://dx.doi.org/10.1007/s11357-020-00300-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7815502PMC
February 2021

Modulation of feeding behavior and metabolism by dynorphin.

Sci Rep 2020 03 2;10(1):3821. Epub 2020 Mar 2.

Institute of Molecular Psychiatry, University of Bonn, Medical Faculty, Venusberg-Campus 1, 53127, Bonn, Germany.

The neuronal regulation of metabolic and behavioral responses to different diets and feeding regimens is an important research area. Herein, we investigated if the opioid peptide dynorphin modulates feeding behavior and metabolism. Mice lacking dynorphin peptides (KO) were exposed to either a normal diet (ND) or a high-fat diet (HFD) for a period of 12 weeks. Additionally, mice had either time-restricted (TR) or ad libitum (AL) access to food. Body weight, food intake and blood glucose levels were monitored throughout the 12-week feeding schedule. Brain samples were analyzed by immunohistochemistry to detect changes in the expression levels of hypothalamic peptides. As expected, animals on HFD or having AL access to food gained more weight than mice on ND or having TR access. Unexpectedly, KO females on TR HFD as well as KO males on AL ND or AL HFD demonstrated a significantly increased body weight gain compared to the respective WT groups. The calorie intake differed only marginally between the genotypes: a significant difference was present in the female ND AL group, where dynorphin KO mice ate more than WT mice. Although female KO mice on a TR feeding regimen consumed a similar amount of food as WT controls, they displayed significantly higher levels of blood glucose. We observed significantly reduced levels of hypothalamic orexigenic peptides neuropeptide Y (NPY) and orexin-A in KO mice. This decrease became particularly pronounced in the HFD groups and under AL condition. The kappa opiod receptor (KOR) levels were higher after HFD compared to ND feeding in the ventral pallidum of WT mice. We hypothesize that HFD enhances dynorphin signaling in this hedonic center to maintain energy homeostasis, therefore KO mice have a more pronounced phenotype in the HFD condition due to the lack of it. Our data suggest that dynorphin modulates metabolic changes associated with TR feeding regimen and HFD consumption. We conclude that the lack of dynorphin causes uncoupling between energy intake and body weight gain in mice; KO mice maintained on HFD become overweight despite their normal food intake. Thus, using kappa opioid receptor agonists against obesity could be considered as a potential treatment strategy.
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http://dx.doi.org/10.1038/s41598-020-60518-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7052232PMC
March 2020

A comprehensive and comparative phenotypic analysis of the collaborative founder strains identifies new and known phenotypes.

Mamm Genome 2020 02 14;31(1-2):30-48. Epub 2020 Feb 14.

Department of Neurology, Friedrich-Baur-Institute, Klinikum Der Ludwig-Maximilians-Universität München, Ziemssenstr. 1a, 80336, Munich, Germany.

The collaborative cross (CC) is a large panel of mouse-inbred lines derived from eight founder strains (NOD/ShiLtJ, NZO/HILtJ, A/J, C57BL/6J, 129S1/SvImJ, CAST/EiJ, PWK/PhJ, and WSB/EiJ). Here, we performed a comprehensive and comparative phenotyping screening to identify phenotypic differences and similarities between the eight founder strains. In total, more than 300 parameters including allergy, behavior, cardiovascular, clinical blood chemistry, dysmorphology, bone and cartilage, energy metabolism, eye and vision, immunology, lung function, neurology, nociception, and pathology were analyzed; in most traits from sixteen females and sixteen males. We identified over 270 parameters that were significantly different between strains. This study highlights the value of the founder and CC strains for phenotype-genotype associations of many genetic traits that are highly relevant to human diseases. All data described here are publicly available from the mouse phenome database for analyses and downloads.
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http://dx.doi.org/10.1007/s00335-020-09827-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060152PMC
February 2020

Soluble Aβ oligomers and protofibrils induce NLRP3 inflammasome activation in microglia.

J Neurochem 2020 12 30;155(6):650-661. Epub 2020 Jan 30.

Department of Neurodegenerative Disease and Geriatric Psychiatry, Bonn, Germany.

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder causing memory loss, language problems and behavioural disturbances. AD is associated with the accumulation of fibrillar amyloid-β (Aβ) and the formation of neurofibrillary tau tangles. Fibrillar Aβ itself represents a danger-associated molecular pattern, which is recognized by specific microglial receptors. One of the key players is formation of the NOD-, LRR- and pyrin domain-containing 3 (NLRP3) inflammasome, whose activation has been demonstrated in AD patient brains and transgenic animal models of AD. Here, we investigated whether Aβ oligomers or protofibrils that represent lower molecular aggregates prior to Aβ deposition are able to activate the NLRP3 inflammasome and subsequent interleukin-1 beta (IL-1β) release by microglia. In our study, we used Aβ preparations of different sizes: small oligomers and protofibrils of which the structure was confirmed by atomic force microscopy. Primary microglial cells from C57BL/6 mice were treated with the respective Aβ preparations and NLRP3 inflammasome activation, represented by caspase-1 cleavage, IL-1β production, and apoptosis-associated speck-like protein containing a CARD speck formation was analysed. Both protofibrils and low molecular weight Aβ aggregates induced a significant increase in IL-1β release. Inflammasome activation was confirmed by apoptosis-associated speck-like protein containing a CARD speck formation and detection of active caspase-1. The NLRP3 inflammasome inhibitor MCC950 completely inhibited the Aβ-induced immune response. Our results show that the NLRP3 inflammasome is activated not only by fibrillar Aβ aggregates as reported before, but also by lower molecular weight Aβ oligomers and protofibrils, highlighting the possibility that microglial activation by these Aβ species may initiate innate immune responses in the central nervous system prior to the onset of Aβ deposition. Cover Image for this issue: https://doi.org/10.1111/jnc.14773.
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http://dx.doi.org/10.1111/jnc.14945DOI Listing
December 2020

Low catalytic activity is insufficient to induce disease pathology in triosephosphate isomerase deficiency.

J Inherit Metab Dis 2019 09 11;42(5):839-849. Epub 2019 Jun 11.

Max Planck Institute for Molecular Genetics, Berlin, Germany.

Triosephosphate isomerase (TPI) deficiency is a fatal genetic disorder characterized by hemolytic anemia and neurological dysfunction. Although the enzyme defect in TPI was discovered in the 1960s, the exact etiology of the disease is still debated. Some aspects indicate the disease could be caused by insufficient enzyme activity, whereas other observations indicate it could be a protein misfolding disease with tissue-specific differences in TPI activity. We generated a mouse model in which exchange of a conserved catalytic amino acid residue (isoleucine to valine, Ile170Val) reduces TPI specific activity without affecting the stability of the protein dimer. TPI mice exhibit an approximately 85% reduction in TPI activity consistently across all examined tissues, which is a stronger average, but more consistent, activity decline than observed in patients or symptomatic mouse models that carry structural defect mutant alleles. While monitoring protein expression levels revealed no evidence for protein instability, metabolite quantification indicated that glycolysis is affected by the active site mutation. TPI mice develop normally and show none of the disease symptoms associated with TPI deficiency. Therefore, without the stability defect that affects TPI activity in a tissue-specific manner, a strong decline in TPI catalytic activity is not sufficient to explain the pathological onset of TPI deficiency.
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http://dx.doi.org/10.1002/jimd.12105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7887927PMC
September 2019

Partial sciatic nerve ligation leads to an upregulation of Ni-resistant T-type Ca currents in capsaicin-responsive nociceptive dorsal root ganglion neurons.

J Pain Res 2019 11;12:635-647. Epub 2019 Feb 11.

Department of Epileptology, University of Bonn Medical Center, Bonn, Germany,

Background: Neuropathic pain resulting from peripheral nerve lesions is a common medical condition, but current analgesics are often insufficient. The identification of key molecules involved in pathological pain processing is a prerequisite for the development of new analgesic drugs. Hyperexcitability of nociceptive DRG-neurons due to regulation of voltage-gated ion-channels is generally assumed to contribute strongly to neuropathic pain. There is increasing evidence, that T-type Ca-currents and in particular the Ca3.2 T-type-channel isoform play an important role in neuropathic pain, but experimental results are contradicting.

Purpose: To clarify the role of T-type Ca-channels and in particular the Ca3.2 T-type-channel isoform in neuropathic pain.

Methods: The effect of partial sciatic nerve ligation (PNL) on pain behavior and the properties of T-type-currents in nociceptive DRG-neurons was tested in wild-type and Ca3.2-deficient mice.

Results: In wild-type mice, PNL of the sciatic nerve caused neuropathic pain and an increase of T-type Ca-currents in capsaicin-responsive neurons, while capsaicin-unresponsive neurons were unaffected. Pharmacological experiments revealed that this upregulation was due to an increase of a Ni-resistant Ca-current component, inconsistent with Ca3.2 up-regulation. Moreover, following PNL Ca3.2-deficient mice showed neuropathic pain behavior and an increase of T-Type Ca-currents indistinguishable to that of PNL treated wild-type mice.

Conclusion: These data suggest that PNL induces an upregulation of T-Type Ca-currents in capsaicin-responsive DRG-neurons mediated by an increase of a Ni-insensitive current component (possibly Ca3.1 or Ca3.3). These findings provide relevance for the development of target specific analgesic drugs.
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http://dx.doi.org/10.2147/JPR.S138708DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6375107PMC
February 2019

A mouse model for intellectual disability caused by mutations in the X-linked 2'‑O‑methyltransferase Ftsj1 gene.

Biochim Biophys Acta Mol Basis Dis 2019 09 14;1865(9):2083-2093. Epub 2018 Dec 14.

Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-University München, Feodor-Lynen Str. 25, 81377 München, Germany.

Mutations in the X chromosomal tRNA 2'‑O‑methyltransferase FTSJ1 cause intellectual disability (ID). Although the gene is ubiquitously expressed affected individuals present no consistent clinical features beyond ID. In order to study the pathological mechanism involved in the aetiology of FTSJ1 deficiency-related cognitive impairment, we generated and characterized an Ftsj1 deficient mouse line based on the gene trapped stem cell line RRD143. Apart from an impaired learning capacity these mice presented with several statistically significantly altered features related to behaviour, pain sensing, bone and energy metabolism, the immune and the hormone system as well as gene expression. These findings show that Ftsj1 deficiency in mammals is not phenotypically restricted to the brain but affects various organ systems. Re-examination of ID patients with FTSJ1 mutations from two previously reported families showed that several features observed in the mouse model were recapitulated in some of the patients. Though the clinical spectrum related to Ftsj1 deficiency in mouse and man is variable, we suggest that an increased pain threshold may be more common in patients with FTSJ1 deficiency. Our findings demonstrate novel roles for Ftsj1 in maintaining proper cellular and tissue functions in a mammalian organism.
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http://dx.doi.org/10.1016/j.bbadis.2018.12.011DOI Listing
September 2019

The transtelephonic electrocardiogram-based triage is an independent predictor of decreased hospital mortality in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention.

J Telemed Telecare 2020 May 10;26(4):216-222. Epub 2018 Dec 10.

Division of Cardiology, University of Debrecen, Hungary.

Introduction: The transtelephonic electrocardiogram has been shown to have a great value in the management of out-of-hospital chest pain emergencies. In our previous study it not only improved the pre-hospital medical therapy and time to intervention, but also the in-hospital mortality in ST-segment elevation myocardial infarction. It was hypothesised that the higher in-hospital survival rate could be due to improved transtelephonic electrocardiogram-based pre-hospital management (electrocardiogram interpretation and teleconsultation) and consequently, better coronary perfusion of patients at the time of hospital admission. To test this hypothesis, our database of ST-segment elevation myocardial infarction patients was evaluated retrospectively for predictors (including transtelephonic electrocardiogram) that may influence in-hospital survival.

Methods And Results: The ST-segment elevation myocardial infarction patients were divided into two groups, namely (a) hospital death patients ( = 49) and (b) hospital survivors (control,  = 726). Regarding pre-hospital medical management, the transtelephonic electrocardiogram-based triage (odds ratio 0.48, confidence interval 0.25-0.92,  = 0.0261) and the administration of optimal pre-hospital medical therapy (acetylsalicylic acid and/or clopidogrel and glycoprotein IIb/IIIa inhibitor) were the most important independent predictors for a decreased risk in our model. At the same time, age, acute heart failure (Killip class >2), successful pre-hospital resuscitation and total occlusion of the infarct-related coronary artery before percutaneous coronary intervention were the most important independent predictors for an increased risk of in-hospital mortality.

Discussion: In ST-segment elevation myocardial infarction patients, (a) an early transtelephonic electrocardiogram-based teleconsultation and triage, (b) optimal pre-hospital antithrombotic medical therapy and (c) the patency and better perfusion of the infarct-related coronary artery on hospital admission are important predictors of a lower in-hospital mortality rate.
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http://dx.doi.org/10.1177/1357633X18814335DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7222284PMC
May 2020

The heterozygous R155C VCP mutation: Toxic in humans! Harmless in mice?

Biochem Biophys Res Commun 2018 09 9;503(4):2770-2777. Epub 2018 Aug 9.

Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, 91054, Erlangen, Germany. Electronic address:

Heterozygous missense mutations in the human VCP gene cause inclusion body myopathy associated with Paget disease of bone and fronto-temporal dementia (IBMPFD) and amyotrophic lateral sclerosis (ALS). The exact molecular mechanisms by which VCP mutations cause disease manifestation in different tissues are incompletely understood. In the present study, we report the comprehensive analysis of a newly generated R155C VCP knock-in mouse model, which expresses the ortholog of the second most frequently occurring human pathogenic VCP mutation. Heterozygous R155C VCP knock-in mice showed decreased plasma lactate, serum albumin and total protein concentrations, platelet numbers, and liver to body weight ratios, and increased oxygen consumption and CD8+/Ly6C + T-cell fractions, but none of the typical human IBMPFD or ALS pathologies. Breeding of heterozygous mice did not yield in the generation of homozygous R155C VCP knock-in animals. Immunoblotting showed identical total VCP protein levels in human IBMPFD and murine R155C VCP knock-in tissues as compared to wild-type controls. However, while in human IBMPFD skeletal muscle tissue 70% of the total VCP mRNA was derived from the mutant allele, in R155C VCP knock-in mice only 5% and 7% mutant mRNA were detected in skeletal muscle and brain tissue, respectively. The lack of any obvious IBMPFD or ALS pathology could thus be a consequence of the very low expression of mutant VCP. We conclude that the increased and decreased fractions of the R155C mutant VCP mRNA in man and mice, respectively, are due to missense mutation-induced, divergent alterations in the biological half-life of the human and murine mutant mRNAs. Furthermore, our work suggests that therapy approaches lowering the expression of the mutant VCP mRNA below a critical threshold may ameliorate the intrinsic disease pathology.
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http://dx.doi.org/10.1016/j.bbrc.2018.08.038DOI Listing
September 2018

Laboratory mouse housing conditions can be improved using common environmental enrichment without compromising data.

PLoS Biol 2018 04 16;16(4):e2005019. Epub 2018 Apr 16.

German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.

Animal welfare requires the adequate housing of animals to ensure health and well-being. The application of environmental enrichment is a way to improve the well-being of laboratory animals. However, it is important to know whether these enrichment items can be incorporated in experimental mouse husbandry without creating a divide between past and future experimental results. Previous small-scale studies have been inconsistent throughout the literature, and it is not yet completely understood whether and how enrichment might endanger comparability of results of scientific experiments. Here, we measured the effect on means and variability of 164 physiological parameters in 3 conditions: with nesting material with or without a shelter, comparing these 2 conditions to a "barren" regime without any enrichments. We studied a total of 360 mice from each of 2 mouse strains (C57BL/6NTac and DBA/2NCrl) and both sexes for each of the 3 conditions. Our study indicates that enrichment affects the mean values of some of the 164 parameters with no consistent effects on variability. However, the influence of enrichment appears negligible compared to the effects of other influencing factors. Therefore, nesting material and shelters may be used to improve animal welfare without impairment of experimental outcome or loss of comparability to previous data collected under barren housing conditions.
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http://dx.doi.org/10.1371/journal.pbio.2005019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5922977PMC
April 2018

Microglial IL-1β progressively increases with duration of alcohol consumption.

Naunyn Schmiedebergs Arch Pharmacol 2018 04 14;391(4):455-461. Epub 2018 Feb 14.

Institute of Molecular Psychiatry, University of Bonn Medical Center, Bonn, Germany.

Chronic alcohol abuse leads to severe brain damage. Although the underlying neuropathological processes are largely unknown, recent studies show that chronic alcohol consumption leads to neuroinflammation and may result in neurodegeneration and impaired neuronal connectivity. Long-term alcohol consumption promotes the production of pro-inflammatory cytokines, such as TNF-α and IL-1β, and activates microglia cells in the brain. As it has not yet been investigated to what extent these processes dependent on the duration of alcohol consumption or whether microglia are source of pro-inflammatory cytokines in vivo, this study investigated the expression of the pro-inflammatory cytokine, IL-1β, in microglia at different time points in mice chronically exposed to alcohol. In the present study, we exposed mice to 2, 6, and 12 months of alcohol consumption, and using immunohistochemistry, analyzed the expression of the microglial marker, Iba1, together with the pro-inflammatory cytokine IL-1β in several cortical regions. Moreover, we investigated the effect of pro-inflammatory activation of microglia on neuronal density. We found that alcohol drinking progressively enhanced IL-1β expression in microglia, which was paralleled with an overall increased microglial density after long-term alcohol consumption. However, we did not find changes in the neuronal density or cortical volume after long-term alcohol consumption. These data show that 12 months of alcohol drinking leads to a pro-inflammatory activation of microglia, which may contribute to impaired neuronal connectivity in the cortex. Anti-inflammatory drug treatment during or after chronic alcohol consumption may thus provide a strategy for restoring brain homeostasis.
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http://dx.doi.org/10.1007/s00210-018-1475-7DOI Listing
April 2018

Developmental programming of somatic growth, behavior and endocannabinoid metabolism by variation of early postnatal nutrition in a cross-fostering mouse model.

PLoS One 2017 31;12(8):e0182754. Epub 2017 Aug 31.

Pediatric Endocrinology Division, Children's Hospital, University of Bonn, Bonn, Germany.

Background: Nutrient deprivation during early development has been associated with the predisposition to metabolic disorders in adulthood. Considering its interaction with metabolism, appetite and behavior, the endocannabinoid (eCB) system represents a promising target of developmental programming.

Methods: By cross-fostering and variation of litter size, early postnatal nutrition of CB6F1-hybrid mice was controlled during the lactation period (3, 6, or 10 pups/mother). After weaning and redistribution at P21, all pups received standard chow ad libitum. Gene expression analyses (liver, visceral fat, hypothalamus) were performed at P50, eCB concentrations were determined in liver and visceral fat. Locomotor activity and social behavior were analyzed by means of computer-assisted videotracking.

Results: Body growth was permanently altered, with differences for length, weight, body mass index and fat mass persisting beyond P100 (all 3>6>10,p<0.01). This was paralleled by differences in hepatic IGF-I expression (p<0.01). Distinct gene expression patterns for key enzymes of the eCB system were observed in fat (eCB-synthesis: 3>6>10 (DAGLα p<0.05; NAPE-PLD p = 0.05)) and liver (eCB-degradation: 3>6>10 (FAAH p<0.05; MGL p<0.01)). Concentrations of endocannabinoids AEA and 2-AG in liver and visceral fat were largely comparable, except for a borderline significance for higher AEA (liver, p = 0.049) in formerly overfed mice and, vice versa, tendencies (p<0.1) towards lower AEA (fat) and 2-AG (liver) in formerly underfed animals. In the arcuate nucleus, formerly underfed mice tended to express more eCB-receptor transcripts (CB1R p<0.05; CB2R p = 0.08) than their overfed fellows. Open-field social behavior testing revealed significant group differences, with formerly underfed mice turning out to be the most sociable animals (p<0.01). Locomotor activity did not differ.

Conclusion: Our data indicate a developmental plasticity of somatic growth, behavior and parameters of the eCB system, with long-lasting impact of early postnatal nutrition. Developmental programming of the eCB system in metabolically active tissues, as shown here for liver and fat, may play a role in the formation of the adult cardiometabolic risk profile following perinatal malnutrition in humans.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182754PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5578498PMC
October 2017

Every-other-day feeding extends lifespan but fails to delay many symptoms of aging in mice.

Nat Commun 2017 07 24;8(1):155. Epub 2017 Jul 24.

Research Group Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany.

Dietary restriction regimes extend lifespan in various animal models. Here we show that longevity in male C57BL/6J mice subjected to every-other-day feeding is associated with a delayed onset of neoplastic disease that naturally limits lifespan in these animals. We compare more than 200 phenotypes in over 20 tissues in aged animals fed with a lifelong every-other-day feeding or ad libitum access to food diet to determine whether molecular, cellular, physiological and histopathological aging features develop more slowly in every-other-day feeding mice than in controls. We also analyze the effects of every-other-day feeding on young mice on shorter-term every-other-day feeding or ad libitum to account for possible aging-independent restriction effects. Our large-scale analysis reveals overall only limited evidence for a retardation of the aging rate in every-other-day feeding mice. The data indicate that every-other-day feeding-induced longevity is sufficiently explained by delays in life-limiting neoplastic disorders and is not associated with a more general slowing of the aging process in mice.Dietary restriction can extend the life of various model organisms. Here, Xie et al. show that intermittent periods of fasting achieved through every-other-day feeding protect mice against neoplastic disease but do not broadly delay organismal aging in animals.
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http://dx.doi.org/10.1038/s41467-017-00178-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537224PMC
July 2017

Fgf9 Mutation Alters Information Processing and Social Memory in Mice.

Mol Neurobiol 2018 Jun 10;55(6):4580-4595. Epub 2017 Jul 10.

Institutes of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany.

In neuropsychiatric diseases, such as major depression and anxiety, pathogenic vulnerability is partially dictated by a genetic predisposition. The search continues to define this genetic susceptibility and establish new genetic elements as potential therapeutic targets. The fibroblast growth factors (FGFs) could be interesting in this regard. This family of signaling molecules plays important roles in development while also functioning within the adult. This includes effects on aspects of brain function such as neurogenesis and synapse formation. Of this family, Fgf9 is expressed in the adult brain, but its functional role is less well defined. In this study, we examined the role of Fgf9 in different brain functions by analyzing the behavior of Fgf9 mutant mice, an Fgf9 allele without the confounding systemic effects of other Fgf9 genetic models. Here, we show that this mutation caused altered locomotor and exploratory reactivity to novel, mildly stressful environments. In addition, mutants showed heightened acoustic startle reactivity as well as impaired social discrimination memory. Notably, there was a substantial decrease in the level of adult olfactory bulb neurogenesis with no difference in hippocampal neurogenesis. Collectively, our findings indicate a role for the Fgf9 mutation in information processing and perception of aversive situations as well as in social memory. Thus, genetic alterations in Fgf9 could increase vulnerability to developing neuropsychiatric disease, and we propose the Fgf9 mutant mice as a valuable tool to study the predictive etiological aspects.
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http://dx.doi.org/10.1007/s12035-017-0659-3DOI Listing
June 2018

: effects on motor phenotypes and the sensorimotor system in mice.

Dis Model Mech 2017 08 23;10(8):981-991. Epub 2017 Jun 23.

Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany

encodes a developmental transcription factor and has been linked to restless legs syndrome (RLS) in genome-wide association studies. RLS is a movement disorder leading to severe sleep reduction and has a substantial impact on the quality of life of patients. In genome-wide association studies, has consistently been the gene with the highest effect size and functional studies suggest a disease-relevant downregulation. Therefore, haploinsufficiency of could be the system with the most potential for modeling RLS in animals. We used heterozygous -knockout mice to study the effects of haploinsufficiency on mouse behavioral and neurological phenotypes, and to relate the findings to human RLS. We exposed the -deficient mice to assays of motor, sensorimotor and cognitive ability, and assessed the effect of a dopaminergic receptor 2/3 agonist commonly used in the treatment of RLS. The mutant mice showed a pattern of circadian hyperactivity, which is compatible with human RLS. Moreover, we discovered a replicable prepulse inhibition (PPI) deficit in the -deficient animals. In addition, these mice were hyposensitive to the PPI-reducing effect of the dopaminergic receptor agonist, highlighting a role of Meis1 in the dopaminergic system. Other reported phenotypes include enhanced social recognition at an older age that was not related to alterations in adult olfactory bulb neurogenesis previously shown to be implicated in this behavior. In conclusion, the -deficient mice fulfill some of the hallmarks of an RLS animal model, and revealed the role of Meis1 in sensorimotor gating and in the dopaminergic systems modulating it.
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http://dx.doi.org/10.1242/dmm.030080DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5560065PMC
August 2017

A chronic low dose of Δ-tetrahydrocannabinol (THC) restores cognitive function in old mice.

Nat Med 2017 Jun 8;23(6):782-787. Epub 2017 May 8.

Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany.

The balance between detrimental, pro-aging, often stochastic processes and counteracting homeostatic mechanisms largely determines the progression of aging. There is substantial evidence suggesting that the endocannabinoid system (ECS) is part of the latter system because it modulates the physiological processes underlying aging. The activity of the ECS declines during aging, as CB1 receptor expression and coupling to G proteins are reduced in the brain tissues of older animals and the levels of the major endocannabinoid 2-arachidonoylglycerol (2-AG) are lower. However, a direct link between endocannabinoid tone and aging symptoms has not been demonstrated. Here we show that a low dose of Δ-tetrahydrocannabinol (THC) reversed the age-related decline in cognitive performance of mice aged 12 and 18 months. This behavioral effect was accompanied by enhanced expression of synaptic marker proteins and increased hippocampal spine density. THC treatment restored hippocampal gene transcription patterns such that the expression profiles of THC-treated mice aged 12 months closely resembled those of THC-free animals aged 2 months. The transcriptional effects of THC were critically dependent on glutamatergic CB1 receptors and histone acetylation, as their inhibition blocked the beneficial effects of THC. Thus, restoration of CB1 signaling in old individuals could be an effective strategy to treat age-related cognitive impairments.
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http://dx.doi.org/10.1038/nm.4311DOI Listing
June 2017

Interplay between H1 and HMGN epigenetically regulates OLIG1&2 expression and oligodendrocyte differentiation.

Nucleic Acids Res 2017 04;45(6):3031-3045

Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

An interplay between the nucleosome binding proteins H1 and HMGN is known to affect chromatin dynamics, but the biological significance of this interplay is still not clear. We find that during embryonic stem cell differentiation loss of HMGNs leads to down regulation of genes involved in neural differentiation, and that the transcription factor OLIG2 is a central node in the affected pathway. Loss of HMGNs affects the expression of OLIG2 as well as that of OLIG1, two transcription factors that are crucial for oligodendrocyte lineage specification and nerve myelination. Loss of HMGNs increases the chromatin binding of histone H1, thereby recruiting the histone methyltransferase EZH2 and elevating H3K27me3 levels, thus conferring a repressive epigenetic signature at Olig1&2 sites. Embryonic stem cells lacking HMGNs show reduced ability to differentiate towards the oligodendrocyte lineage, and mice lacking HMGNs show reduced oligodendrocyte count and decreased spinal cord myelination, and display related neurological phenotypes. Thus, the presence of HMGN proteins is required for proper expression of neural differentiation genes during embryonic stem cell differentiation. Specifically, we demonstrate that the dynamic interplay between HMGNs and H1 in chromatin epigenetically regulates the expression of OLIG1&2, thereby affecting oligodendrocyte development and myelination, and mouse behavior.
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http://dx.doi.org/10.1093/nar/gkw1222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389484PMC
April 2017

The First Scube3 Mutant Mouse Line with Pleiotropic Phenotypic Alterations.

G3 (Bethesda) 2016 12 7;6(12):4035-4046. Epub 2016 Dec 7.

German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany.

The vertebrate Scube (Signal peptide, CUB, and EGF-like domain-containing protein) family consists of three independent members, Scube1-3, which encode secreted cell surface-associated membrane glycoproteins. Limited information about the general function of this gene family is available, and their roles during adulthood. Here, we present the first Scube3 mutant mouse line (Scube3), which clearly shows phenotypic alterations by carrying a missense mutation in exon 8, and thus contributes to our understanding of SCUBE3 functions. We performed a detailed phenotypic characterization in the German Mouse Clinic (GMC). Scube3 mutants showed morphological abnormalities of the skeleton, alterations of parameters relevant for bone metabolism, changes in renal function, and hearing impairments. These findings correlate with characteristics of the rare metabolic bone disorder Paget disease of bone (PDB), associated with the chromosomal region of human SCUBE3 In addition, alterations in energy metabolism, behavior, and neurological functions were detected in Scube3 mice. The Scube3 mutant mouse line may serve as a new model for further studying the effect of impaired SCUBE3 gene function.
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http://dx.doi.org/10.1534/g3.116.033670DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5144972PMC
December 2016

Cannabinoid Type 2 Receptors Mediate a Cell Type-Specific Plasticity in the Hippocampus.

Neuron 2016 05 28;90(4):795-809. Epub 2016 Apr 28.

Neuroscience Research Center (NWFZ), 10117 Berlin, Germany; NeuroCure Cluster of Excellence, 10117 Berlin, Germany; Bernstein Center for Computational Neuroscience (BCCN), 10115 Berlin, Germany; Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany; Einstein Center for Neurosciences, 10117 Berlin, Germany. Electronic address:

Endocannabinoids (eCBs) exert major control over neuronal activity by activating cannabinoid receptors (CBRs). The functionality of the eCB system is primarily ascribed to the well-documented retrograde activation of presynaptic CB1Rs. We find that action potential-driven eCB release leads to a long-lasting membrane potential hyperpolarization in hippocampal principal cells that is independent of CB1Rs. The hyperpolarization, which is specific to CA3 and CA2 pyramidal cells (PCs), depends on the activation of neuronal CB2Rs, as shown by a combined pharmacogenetic and immunohistochemical approach. Upon activation, they modulate the activity of the sodium-bicarbonate co-transporter, leading to a hyperpolarization of the neuron. CB2R activation occurred in a purely self-regulatory manner, robustly altered the input/output function of CA3 PCs, and modulated gamma oscillations in vivo. To conclude, we describe a cell type-specific plasticity mechanism in the hippocampus that provides evidence for the neuronal expression of CB2Rs and emphasizes their importance in basic neuronal transmission.
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http://dx.doi.org/10.1016/j.neuron.2016.03.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5533103PMC
May 2016

Generation and Standardized, Systemic Phenotypic Analysis of Pou3f3L423P Mutant Mice.

PLoS One 2016 22;11(3):e0150472. Epub 2016 Mar 22.

Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, 81377, Munich, Germany.

Increased levels of blood plasma urea were used as phenotypic parameter for establishing novel mouse models for kidney diseases on the genetic background of C3H inbred mice in the phenotype-driven Munich ENU mouse mutagenesis project. The phenotypically recessive mutant line HST011 was established and further analyzed. The causative mutation was detected in the POU domain, class 3 transcription factor 3 (Pou3f3) gene, which leads to the amino acid exchange Pou3f3L423P thereby affecting the conserved homeobox domain of the protein. Pou3f3 homozygous knockout mice are published and show perinatal death. Line Pou3f3L423P is a viable mouse model harboring a homozygous Pou3f3 mutation. Standardized, systemic phenotypic analysis of homozygous mutants was carried out in the German Mouse Clinic. Main phenotypic changes were low body weight and a state of low energy stores, kidney dysfunction and secondary effects thereof including low bone mineralization, multiple behavioral and neurological defects including locomotor, vestibular, auditory and nociceptive impairments, as well as multiple subtle changes in immunological parameters. Genome-wide transcriptome profiling analysis of kidney and brain of Pou3f3L423P homozygous mutants identified significantly regulated genes as compared to wild-type controls.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0150472PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4803225PMC
August 2016

Analysis of mammalian gene function through broad-based phenotypic screens across a consortium of mouse clinics.

Nat Genet 2015 Sep 27;47(9):969-978. Epub 2015 Jul 27.

Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München, Munich, Germany.

The function of the majority of genes in the mouse and human genomes remains unknown. The mouse embryonic stem cell knockout resource provides a basis for the characterization of relationships between genes and phenotypes. The EUMODIC consortium developed and validated robust methodologies for the broad-based phenotyping of knockouts through a pipeline comprising 20 disease-oriented platforms. We developed new statistical methods for pipeline design and data analysis aimed at detecting reproducible phenotypes with high power. We acquired phenotype data from 449 mutant alleles, representing 320 unique genes, of which half had no previous functional annotation. We captured data from over 27,000 mice, finding that 83% of the mutant lines are phenodeviant, with 65% demonstrating pleiotropy. Surprisingly, we found significant differences in phenotype annotation according to zygosity. New phenotypes were uncovered for many genes with previously unknown function, providing a powerful basis for hypothesis generation and further investigation in diverse systems.
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http://dx.doi.org/10.1038/ng.3360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4564951PMC
September 2015

MIM-Induced Membrane Bending Promotes Dendritic Spine Initiation.

Dev Cell 2015 Jun 4;33(6):644-59. Epub 2015 Jun 4.

Neuroscience Center, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland. Electronic address:

Proper morphogenesis of neuronal dendritic spines is essential for the formation of functional synaptic networks. However, it is not known how spines are initiated. Here, we identify the inverse-BAR (I-BAR) protein MIM/MTSS1 as a nucleator of dendritic spines. MIM accumulated to future spine initiation sites in a PIP2-dependent manner and deformed the plasma membrane outward into a proto-protrusion via its I-BAR domain. Unexpectedly, the initial protrusion formation did not involve actin polymerization. However, PIP2-dependent activation of Arp2/3-mediated actin assembly was required for protrusion elongation. Overexpression of MIM increased the density of dendritic protrusions and suppressed spine maturation. In contrast, MIM deficiency led to decreased density of dendritic protrusions and larger spine heads. Moreover, MIM-deficient mice displayed altered glutamatergic synaptic transmission and compatible behavioral defects. Collectively, our data identify an important morphogenetic pathway, which initiates spine protrusions by coupling phosphoinositide signaling, direct membrane bending, and actin assembly to ensure proper synaptogenesis.
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http://dx.doi.org/10.1016/j.devcel.2015.04.014DOI Listing
June 2015

CB1 receptors modulate affective behaviour induced by neuropathic pain.

Brain Res Bull 2015 May 8;114:42-8. Epub 2015 Apr 8.

Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany. Electronic address:

Patients suffering from chronic pain are often diagnosed with a psychiatric condition, in particular generalized anxiety and major depression. The underlying pathomechanisms contributing to this comorbidity, however, are not entirely clear. In this manuscript we have focussed on the potential role of the cannabinoid receptor CB1, because it is known to modulate neuronal circuits contributing to chronic pain states and affective behaviours. For this purpose we analysed the consequences of a partial sciatic nerve ligation on anxiety- and depression-related behaviours in mice lacking CB1 receptors. Our results show that the development of mechanical hypersensitivity was similar in CB1 deficient mice and wild type controls. However, CB1 knockouts showed much more pronounced behavioural manifestations of anxiety-related behaviours in the light-dark and zero-maze tests, sucrose anhedonia, and disturbed home-cage activity. These results indicate that the endocannabinoid system affects chronic pain-induced mood changes through CB1 receptors.
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http://dx.doi.org/10.1016/j.brainresbull.2015.03.005DOI Listing
May 2015

Interaction of cannabinoid receptor 2 and social environment modulates chronic alcohol consumption.

Behav Brain Res 2015 28;287:163-71. Epub 2015 Mar 28.

Institute of Molecular Psychiatry, University of Bonn Medical Center, Germany. Electronic address:

Genetic and environmental factors contribute nearly in equal power to the development of alcoholism. Environmental factors, such as negative life events or emotionally disruptive conditions, initiate and promote alcohol drinking and relapse. The endocannabinoid system is involved in hedonic control and modulates stress reactivity. Furthermore, chronic alcohol drinking alters endocannabinoid signalling, which in turn influences the stress reactivity. Recently, it has been shown that CB2 receptor activity influences stress sensitivity and alcohol drinking. We hypothesized that CB2 receptors influence the impact of environmental risk factors on alcohol preference and consumption. Therefore, in this study, we investigated the alcohol-drinking pattern of wild-type and CB2-deficient animals under single- and group-housing conditions using different alcohol-drinking models, such as forced drinking, intermittent forced drinking and two-bottle choice paradigms. Our data showed that CB2 receptor modulates alcohol consumption and reward. Interestingly, we detected that lack of CB2 receptors led to increased alcohol drinking in the intermittent forced drinking paradigm under group-housing conditions. Furthermore, we found that CB2 knockout mice consumed more food and that their body weight gain was modulated by social environment. On the basis of these data, we conclude that social environment critically affects the modulatory function of CB2 receptors, especially in alcohol intake. These findings suggest that a treatment strategy targeting CB2 receptors may have a beneficial effect on pathological drinking, particularly in situations of social stress and discomfort.
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http://dx.doi.org/10.1016/j.bbr.2015.03.051DOI Listing
January 2016

Relationship between reversibility score on corresponding left ventricular segments and fractional flow reserve in coronary artery disease.

Anatol J Cardiol 2015 Jun 11;15(6):469-74. Epub 2014 Jul 11.

Institute of Cardiology, University of Debrecen Clinical Center; Debrecen-Hungary.

Objective: The objective of this study was to find the correlation between the severity of perfusion abnormality detected by scintigraphy and the FFR value, as well as the localization of a particular coronary lesion. On the basis of FFR values and the corresponding left ventricular segments, we proposed a combined index to aim for better correlation with myocardial ischemia than the FFR parameter alone.

Methods: Twenty-eight patients (male: 22, female: 6, age 62±7.62) having FFR measurements and myocardial perfusion SPECT studies were enrolled in our retrospective analysis. FFR measurements on 36 vessels (20 LAD, 6 LCx, 10 RCA) with intermediate stenosis (40%-60%) were compared to the Tc-99m SestaMIBI myocardial perfusion SPECT studies. SPECT studies were performed before the invasive procedure in all cases. We introduced a new ischemic index, the left ventricular ischemic index (LVIi), by combining FFR values with the number of corresponding myocardial segments (N) [LVIi=N x (1-FFR)]. This index correlated with the regional myocardial perfusion defects identified on the scintigrams. A perfusion reversibility score of 2 or above was considered indicative of active ischemia (regional difference score: rDSc). For the statistical analysis, we used linear regression analysis and receiver operating characteristic (ROC) curve analysis to compare the different parameters.

Results: A close linear relationship was found between the LVIi and rDSc values (p<0.001) with linear regression analysis. When analyzing all FFR values independently of the localization of the lesions, they also correlated significantly to the rDSc, but this relation was not as close. LVIi predicted active ischemia (≥2 rDSc) on myocardial scintigraphy with 78% sensitivity and 94% specificity when the cutoff value was set to 0.96. FFR alone predicted ischemia on scintigraphy with 72% sensitivity and 94% specificity at the best 0.8 cut-off value. The area under the ROC curve was significantly higher for LVIi than FFR (0.94 vs. 0.87; p<0.05).

Conclusion: The scintigraphic data indicate that an LVIi >0.96 implies a clinically relevant stenotic lesion. In our opinion, FFR values, weighted with the corresponding left ventricular segments, should be taken into consideration for the best clinical decision-making.
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http://dx.doi.org/10.5152/akd.2014.5500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5779139PMC
June 2015

Wall motion changes in myocardial infarction in relation to the time elapsed from symptoms until revascularization.

Anatol J Cardiol 2015 May 11;15(5):363-70. Epub 2014 Jul 11.

Institute of Cardiology and Heart Surgery, University of Debrecen Clinical Center; Debrecen-Hungary.

Objective: Wall motion abnormalities during acute ST-segment elevation myocardial infarction (STEMI) and the improvement after recanalization depend on the conditions of the coronary occlusion.

Methods: Fifty-seven patients with first-ever STEMI due to one-artery occlusion, treated with primary PCI, were evaluated. Area at risk and left ventricular wall motion abnormalities were localized with coronary angiography and echocardiography and then compared in relation to the time elapsed from the onset of symptoms at the time of infarction and at 3 months. Left ventricular diameters and ejection fractions were evaluated in relation to the ischemic time.

Results: Three hundred forty-one affected left ventricular segments were detected with angiography, while echocardiography showed 206 segments with motion abnormality. No correlation was found between the regional wall motion index in the area at risk and the time elapsed from the beginning of symptoms. However, the improvement in wall motion abnormalities at the follow-up was dependent on the ischemic time (r=-0.29, p<0.03). The early subgroup showed significant improvement in left ventricular ejection fraction at follow-up (p=0.03), whereas in the late subgroup, a significant increase in left ventricle diameters was observed.

Conclusion: Our results first demonstrate in humans that in the early hours from the occlusion of the coronary artery, the extent and severity of the wall motion abnormalities inside the area at risk show large variability without relation to the elapsed time since the onset of symptoms. On the other hand, the results of follow-up echocardiography proved that the wall motion improvement was highly dependent on the ischemic time.
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http://dx.doi.org/10.5152/akd.2014.5457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5779171PMC
May 2015

MiR-34a deficiency accelerates medulloblastoma formation in vivo.

Int J Cancer 2015 May 25;136(10):2293-303. Epub 2014 Nov 25.

Department of Pediatric Oncology and Hematology, University Children's Hospital Essen, Hufelandstr. 55 45147, Essen, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany; German Cancer Research Center (DKFZ), D-69120, Heidelberg, Germany.

Previous studies have evaluated the role of miRNAs in cancer initiation and progression. MiR-34a was found to be downregulated in several tumors, including medulloblastomas. Here we employed targeted transgenesis to analyze the function of miR-34a in vivo. We generated mice with a constitutive deletion of the miR-34a gene. These mice were devoid of mir-34a expression in all analyzed tissues, but were viable and fertile. A comprehensive standardized phenotypic analysis including more than 300 single parameters revealed no apparent phenotype. Analysis of miR-34a expression in human medulloblastomas and medulloblastoma cell lines revealed significantly lower levels than in normal human cerebellum. Re-expression of miR-34a in human medulloblastoma cells reduced cell viability and proliferation, induced apoptosis and downregulated the miR-34a target genes, MYCN and SIRT1. Activation of the Shh pathway by targeting SmoA1 transgene overexpression causes medulloblastoma in mice, which is dependent on the presence and upregulation of Mycn. Analysis of miR-34a in medulloblastomas derived from ND2:SmoA1(tg) mice revealed significant suppression of miR-34a compared to normal cerebellum. Tumor incidence was significantly increased and tumor formation was significantly accelerated in mice transgenic for SmoA1 and lacking miR-34a. Interestingly, Mycn and Sirt1 were strongly expressed in medulloblastomas derived from these mice. We here demonstrate that miR-34a is dispensable for normal development, but that its loss accelerates medulloblastomagenesis. Strategies aiming to re-express miR-34a in tumors could, therefore, represent an efficient therapeutic option.
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http://dx.doi.org/10.1002/ijc.29294DOI Listing
May 2015
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