Forage peanut legume as a strategy for improving beef production without increasing livestock greenhouse gas emissions

The transformation of pastures from a degraded state to sustainable productivity is a major challenge in tropical livestock production. Stoloniferous forage legumes such as Arachis pintoi (forage peanut) are one of the most promising alternatives for intensifying pasture-based beef livestock operations with reduced greenhouse gas (GHG) emissions. This 2-year study assessed beef cattle performance, nutrient intake and digestibility, and balance of GHG emissions in three pasture types (PT): (1) mixed Palisade grass - Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster (syn. Brachiaria brizantha Stapf cv. Marandu) and forage peanut (A. pintoi Krapov. & W.C. Greg. cv. BRS Mandobi) pastures (Mixed), (2) monoculture Palisade grass pastures with 150 kg of N/ha per year (Fertilised), and (3) monoculture Palisade grass without N fertiliser (Control). Continuous stocking with a variable stocking rate was used in a randomised complete block design, with four replicates per treatment. The average daily gain and carcass gain were not influenced by the PT (P = 0.439 and P = 0.100, respectively) and were, on average, 0.433 kg/animal per day and 83.4 kg/animal, respectively. Fertilised and Mixed pastures increased by 102 and 31.5%, respectively, the liveweight gain per area (kg/ha/yr) compared to the Control pasture (P < 0.001). The heifers in the Mixed pasture had lower CH4 emissions (g/animal per day; P = 0.009), achieving a reduction of 12.6 and 10.1% when compared to the Fertilised and Control pastures, respectively. Annual (N2O) emissions (g/animal) and per kg carcass weight gain were 59.8 and 63.1% lower, respectively, in the Mixed pasture compared to the Fertilised pasture (P < 0.001). Mixed pasture mitigated approximately 23% of kg CO2eq/kg of carcass when substituting 150 kg of N/ha per year via fertiliser. Mixed pastures with forage peanut are a promising solution to recover degraded tropical pastures by providing increased animal production with lower GHG emissions.

Differential gene expression in layer 3 pyramidal neurons across 3 regions of the human cortical visual spatial working memory network

Visual spatial working memory (vsWM) is mediated by a distributed cortical network composed of multiple nodes, including primary visual (V1), posterior parietal (PPC), and dorsolateral prefrontal (DLPFC) cortices. Feedforward and feedback information is transferred among these nodes via projections furnished by pyramidal neurons (PNs) located primarily in cortical layer 3. Morphological and electrophysiological differences among layer 3 PNs across these nodes have been reported; however, the transcriptional signatures underlying these differences have not been examined in the human brain. Here we interrogated the transcriptomes of layer 3 PNs from 39 neurotypical human subjects across 3 critical nodes of the vsWM network. Over 8,000 differentially expressed genes were detected, with more than 6,000 transcriptional differences present between layer 3 PNs in V1 and those in PPC and DLPFC. Additionally, over 600 other genes differed in expression along the rostral-to-caudal hierarchy formed by these 3 nodes. Moreover, pathway analysis revealed enrichment of genes in V1 related to circadian rhythms and in DLPFC of genes involved in synaptic plasticity. Overall, these results show robust regional differences in the transcriptome of layer 3 PNs, which likely contribute to regional specialization in their morphological and physiological features and thus in their functional contributions to vsWM.

Lung transplantation for idiopathic pulmonary fibrosis enriches for individuals with telomere-mediated disease

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is the most common indication for lung transplantation in North America and variants in telomere-maintenance genes are the most common identifiable cause of IPF. We reasoned that younger IPF patients are more likely to undergo lung transplantation and we hypothesized that lung transplant recipients would be enriched for individuals with telomere-mediated disease due to the earlier onset and more severe disease in these patients.

METHODS

Individuals with IPF who underwent lung transplantation or were evaluated in an interstitial lung disease specialty clinic who did not undergo lung transplantation were examined. Genetic evaluation was completed via whole genome sequencing (WGS) of 426 individuals and targeted sequencing for 5 individuals. Rare variants in genes previously associated with IPF were classified using the American College of Medical Genetics guidelines. Telomere length from WGS data was measured using TelSeq software. Patient characteristics were collected via medical record review.

RESULTS

Of 431 individuals, 149 underwent lung transplantation for IPF. The median age of diagnosis of transplanted vs non-transplanted individuals was significantly younger (60 years vs 70 years, respectively, p<0.0001). IPF lung transplant recipients (IPF-LTRs) were twice as likely to have telomere-related rare variants compared to non-transplanted individuals (24% vs 12%, respectively, p=0.0013). IPF-LTRs had shorter telomeres than non-transplanted IPF patients (p=0.0028) and >85% had telomeres below the age-adjusted mean. Post-transplant survival and CLAD were similar amongst IPF-LTRs with rare variants in telomere-maintenance genes compared to those without, as well as in those with short telomeres versus longer telomeres.

CONCLUSIONS

There is an enrichment for telomere-maintenance gene variants and short telomeres among IPF-LTRs. However, transplant outcomes of survival and CLAD do not differ by gene variants or telomere length within IPF-LTRs. Our findings support individual with telomere-mediated disease should not be excluded from lung transplantation and focusing research efforts on therapies directed toward individuals with short-telomere mediated disease.

Crucial role of extra-domain A containing fibronectin for the development of pulmonary hypertension and associated right heart failure

Background

Pulmonary vascular and right ventricular myocardial remodelling are unique phenomena in PH progression. Both processes are accompanied by an abundant re-expression of the extra-domain A of fibronectin (ED-A+ Fn) therefore qualifying as promising biomarker or even therapeutic target. Nevertheless, its functional role in PH pathogenesis remains unclear until now. Objective: The purpose of our study was to analyse the development of PH and RHF in a mouse model of monocrotaline (MCT)-induced PH comparing C57BL/6 ED-A+ Fn knockout (KO) and wild-type (WT) mice.

Methods

PH was induced by subcutaneous injection of a single dose of MCT (60 mg/kg body weight). Subgroups were additionally treated with the dual endothelin receptor antagonist Macitentan (MAC, 15mg/kg body weight per day from day 14 to 28). There were 6 experimental groups: sham-treated control WT mice (WTco, n=4); MCT induced PH WT mice (WTPH, n=6); MCT induced PH WT mice treated with MAC (WTPH_MAC, n=6); sham-treated control KO mice (KOco, n=4); MCT induced PH KO mice (KOPH, n=6); MCT induced PH KO mice treated with MAC (KOPH_MAC, n=6). Between day 26 and 28, transthoracic echocardiography and right heart catheterization were performed. Both, lung and cardiac tissue samples were subjected to histological analyses.

Results

Right heart catheterization revealed significantly increased RVPsys values in WTPH (87.0±16.4mmHg) compared to WTco (36.1±9.4mmHg; p=0.034) animals, which showed, at least in trend, a diminution in the WTPH_MAC group (67.1±20.9mmHg; p=n.s.). There was a non-significant increase in RVPsys in the KOPH (55.6±14.9mmHg) compared to KOco mice (37.2±5.6mmHg; p=n.s.) without any differences compared to the KOPH_MAC group (60.9±14.0mmHg; p=n.s.). When comparing the WTPH and the KOPH group, RVPsys was significantly lower in the KO animals (p=0.014), while there were no differences between the WTPH_MAC and the KOPH_MAC group (p=n.s.). Echocardiographic evaluation including surrogate parameters of right ventricular (RV) overload and failure were significantly altered in WTPH compared to WTco animals (p&lt;0.05) and could not be shown to be relevantly improved in the WTPH_MAC group (p=n.s.). The majority of echocardiographic parameters did not significantly differ between the KOPH and the KOco group (p=n.s.). Lung tissue analysis revealed significant alterations in both, the WTPH and the KOPH group, each compared to the corresponding control (p&lt;0.05). The level of lung tissue damage was significantly decreased in KOPH compared to WTPH mice (p&lt;0.05). In RV, the amount of interstitial fibrosis was increased in the WTPH (p=0.009) but not in the KOPH group (p=n.s.), each compared to the corresponding controls.

Conclusions

The findings of the current study underline the hypothesis that ED-A+ Fn is a key player in the pathogenesis of PH and associated RHF. Thus, it might represent a promising therapeutic target, e.g., by the administration of neutralizing antibodies.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): University Hospital Jena

Effects of supplementation with corn distillers' dried grains on animal performance, nitrogen balance, and enteric CH4 emissions of young Nellore bulls fed a high-tropical forage diet

The inclusion of corn-dried distillers' grains (DDG) could be an alternative supplement to increase animal performance, nitrogen efficiency usage (NEU), and decrease enteric methane (CH₄) emissions. Our goal was to determine whether DDG could replace a traditional supplement (cottonseed meal) without affecting animal performance, N balance, and CH₄ emissions. The experiment was conducted during the forage growing season (December to April), with 15 d adaptation, and a 112 d experimental period. The experimental design was completely randomized with four treatments: a mineral supplement (MS), cottonseed meal supplement (CS), 50% replacement of CS by DDG (50DDG), and 100% replacement of CS by DDG (100DDG). Cottonseed meal and DDG were used as protein supplement. A total of 12 paddocks, 3 per treatment, were used to measure forage mass: morphological and chemical composition of forage, forage allowance, and animal performance. Six animals per treatment were used to evaluate DM intake, digestibility, CH₄ emissions, microbial protein production (MCP), and NEU of each treatment. Eighty-one Young Nellore bulls (48 testers, 12 per treatments and 33 adjusters) with initial BW of 255 ± 5 kg (10-12 months old) were supplemented with each supplement type at a level of 0.3% of BW. Pasture management was continuous stocking with a variable stocking rate (put-and-take). Enteric CH₄ was measured using the gas tracer technique. The MCP was quantified using purine derivatives and the NEU mass balance. No differences were found in nutrient intake (P > 0.228). Individual animal performance and gain per area were higher in the treatments with concentrates compared with that of MS; however, there was no difference among treatments CS, 50DDG, and 100DDG. The ADG was 0.83 for MS and 1.08 kg/animal/d when supplemented (P < 0.05). Gain per hectare was 709 kg/ha for MS and 915 kg/ha when supplemented with concentrates (P < 0.05). There was no difference in CH₄ production among treatments that average 180 g/animal/d; however, CH₄ per kg of gain was reduced with CS. The CH₄ conversion factor averaged 5.91%. There was no difference in the synthesis of MCP and NEU. Corn DDG can replace 100% of cottonseed meal as a protein source for supplementation of young Nellore bulls grazing in tropical pastures without affecting animal performance, NEU, MCP, and CH₄ emissions.

Progressive inclusion of pearl millet herbage as a supplement for dairy cows fed mixed rations: Effects on methane emissions, dry matter intake, and milk production

The inclusion of grazing in dairy feeding systems can improve animal welfare and reduce feed costs and labor for animal care and manure management. This work aimed to evaluate the effects of including pearl millet herbage (Pennisetum glaucum 'Campeiro') as a supplement for dairy cows fed total mixed rations (TMR). The treatments included 100% TMR offered ad libitum (control, TMR₁₀₀), 75% TMR ad libitum intake + access to grazing of a pearl millet pasture between the morning and afternoon milkings (7 h/d; pTMR₇₅), and 50% TMR ad libitum intake + access to grazing of a pearl millet pasture between the morning and afternoon milkings (7 h/d; pTMR₅₀). Nine multiparous Holstein and F₁ Jersey × Holstein cows were distributed in a replicated 3 × 3 Latin square design with 3 periods of 21 d (a 16-d adaptation period and a 5-d measurement period). Cows in the TMR₇₅ and TMR₅₀ groups strip-grazed a pearl millet pasture with pre- and postgrazing sward height targets of 60 and 30 cm, respectively. The herbage dry matter intake (DMI) increased with decreasing mixed ration supplies, and the total DMI decreased linearly from 19.0 kg/d in the TMR₁₀₀ group to 18.0 kg/d in the pTMR₅₀ group. Milk production decreased linearly from 24.0 kg/d in the TMR₁₀₀ group to 22.4 kg/d in the pTMR₅₀ group, and energy-corrected milk (ECM) production decreased linearly from 26.0 kg/d to 23.6 kg/d. Enteric methane (CH₄) emissions decreased linearly from 540 g/d in the TMR₁₀₀ group to 436 g/d in the pTMR₅₀ group, and CH₄ yields (g/kg of DMI) tended to decrease linearly. The CH₄ intensity was similar between treatments, averaging 20 g of CH₄/kg of ECM. The inclusion of pearl millet herbage in the dairy cow diets decreased the total DMI and milk production to a small extent without affecting CH₄ intensity (g/kg of ECM).

P5579Pre-existing depression significantly improves after transcatheter aortic valve implantation (TAVI): analysis of long-term effects and screening for novel biomarkers

Background and aims

Depression negatively affects symptom tolerance as well as clinical endpoints in cardiovascular diseases. For aortic stenosis (AS) patients undergoing Transcatheter Aortic Valve Implantation (TAVI), a reduction of pre-existing depression and anxiety in short term follow-up could be recently shown by our group. The current study was aimed to evaluate these effects in long-term follow-up and to screen for promising biomarkers, e.g., 5-Hydroxytryptamin (5-HT), Endothelin-1 (ET-1), neutrophil gelatinase associated lipocalin (NGAL) and Tenascin-C (Tn-C) variants. These molecules might reflect a pathophysiological link between reverse cardiac remodelling and mental state.

Methods

The study included 182 out of 226 patients who underwent TAVI at the University Hospital Jena since August 2016. Besides clinical parameters, the EuroQol questionnaire (EQ-5D), the Visual Analog Scale (VAS), the Clinical Frailty Scale (CFS) and, to specifically detect depression and anxiety, the Hospital Anxiety and Depression Scale (HADS-D) were assessed directly before TAVI, at 6-weeks, 6-month as well as 12- months follow-up. Blood samples were withdrawn before TAVI and during 6-weeks and 6-month follow-up.

Results

Study patients represented a typical moderate- to high-risk TAVI collective (n=182, mean age 78,1±7.9 years, 46,9% male, mean STS-Score 4.6±2,8). Before TAVI, analysis of HADS revealed ≥8 points, defined as pathologic, for depression and/or anxiety in 71 patients (39%) and for depression only in 46 patients (25.3%). In the depressive subgroup, there was a significant improvement after 6 weeks for depression (p<0.001) and anxiety (p=0.006). BNP serum levels were significantly reduced (p=0.007) and 6-minutes' walk distance was significantly increased from a low level (p=0.008), VAS, CFS and 2 out of 5 parameters of the EQ-5D were significantly improved (p<0.05). All observed short-term effects continued at stable levels over time. A pre-existing depression state was not associated with an increased long-term mortality rate, which was 14.8%. Circulating biomarker levels in depressive patients before and 6 weeks after TAVI revealed no significant differences. At the 6 months follow-up, only for C+ Tn-C there was a significant increase compared to both, the timepoint before TAVI (p=0.046) and the 6 weeks follow-up (p=0.033).

Conclusions

Already in short-term follow-up after successful TAVI, a remarkable decrease in depression could be detected using HADS. Especially in the depressive subgroup, the patients showed benefit also with respect to other surrogate parameters of mental health and functional performance. Interestingly, these effects were completely maintained not only in mid-term but also in long-term follow-up. We could show that the improvement of depression after TAVI is reflected by a delayed decrease of C+ Tn-C serum levels. C+ Tn-C can be suggested as promising biomarker possibly linked to reactive depression in somatic diseases.

P6345Chronic cardiac allograft rejection after heterotopic rat heart transplantation: ed-a but not ed-b domain containing fibronectin as novel serum biomarker of cardiac allograft vasculopathy

Background and aims

Diagnosis of Cardiac Allograft Vasculopathy (CAV) following heart transplantation (HTX) is still challenging but of prognostic relevance. Thus, the identification of biomarkers non-invasively detecting the disease is an hitherto unmet clinical need. Fetal variants of the cell adhesion modulating protein Fibronectin (Fn) could be proven to re-occur in the context of chronic rejection in rat and human cardiac tissue after HTX in spatial association to CAV and fibrosis. This study was aimed to determine serum levels of fetal Fn variants in a heterotopic rat HTX model of chronic rejection.

Methods

Chronic cardiac allograft rejection was induced by heterotopic rat HTX using inbred male Lewis (LEW) rats as donors and Fisher (F344) rats as recipients (n=24). After microsurgical modifications, the allograft was implanted into the abdomen of the recipient animal. Rats were sacrificed after 70 days. Untreated F344 rats were used as controls (n=6). Cardiac tissue was subjected to histological analysis according to a recently established sum-score system between 0 and 10 (0 = no detectable rejection; 1 to 3 = weak rejection; 4 to 7 = moderate rejection; and 8 to 10 = severe rejection). The score includes all relevant parameters of chronic rejection (CAV, lymphocyte infiltration, cardiomyocyte degeneration, fibrosis). Brain natriuretic peptide (BNP) was determined by a commercially available ELISA. Serum levels of both, ED-A domain containing Fn (ED-A+ Fn) and ED-B domain containing Fn (ED-B+ Fn) were quantified using ELISA protocols established in our group.

Results

Final experiments were performed on day 70, mortality rate was 0%. Histological analysis revealed a chronic cardiac allograft rejection in all transplanted animals (mean sum-score 6.92±1.94) while controls did not exhibit relevant alterations (mean sum-score 0.1±0.2; p<0.001). There were significantly elevated BNP levels in HTX rats (76.16±23.22 pg/ml) compared to controls (352.23±132.09 pg/ml; p<0.001). BNP showed a strong positive correlation to the histological sum-score (r=0.653; p<0.001). Serum levels of ED-A+ Fn (HTX: 34.42±11.4 μg/ml, controls: 17.3±6.13 μg/ml; p=0.009) but not ED-B+ Fn (HTX: 8.58±4.12 μg/ml, controls: 9.4±2.61 μg/ml; p=0.804) were significantly increased in HTX rats qualifying ED-A+ Fn for further analysis with respect to histological signs of chronic rejection. Interestingly, there is a noticeable association to the occurrence of CAV representing 1 out of 4 parameters included in the histological sum-score (r=0.51; p=0.006).

Conclusions

Chronic cardiac allograft rejection and, in particular, CAV as major long-term prognosis-limiting factor after HTX are accompanied by both, a re-expression and vessel associated tissue deposition of ED-A+ Fn and also a relevant liberation into blood. These results underline the potential impact of ED-A+ Fn as biomarker or potential therapeutic target patients that underwent HTX.

A Genome-Wide Analysis of the Penumbral Volume in Inbred Mice following Middle Cerebral Artery Occlusion

Following ischemic stroke, the penumbra, at-risk neural tissue surrounding the core infarct, survives for a variable period of time before progressing to infarction. We investigated genetic determinants of the size of penumbra in mice subjected to middle cerebral artery occlusion (MCAO) using a genome-wide approach. 449 male mice from 33 inbred strains underwent MCAO for 6 hours (215 mice) or 24 hours (234 mice). A genome-wide association study using genetic data from the Mouse HapMap project was performed to examine the effects of genetic variants on the penumbra ratio, defined as the ratio of the infarct volume after 6 hours to the infarct volume after 24 hours of MCAO. Efficient mixed model analysis was used to account for strain interrelatedness. Penumbra ratio differed significantly by strain (F = 2.7, P < 0.001) and was associated with 18 significant SNPs, including 6 protein coding genes. We have identified 6 candidate genes for penumbra ratio: Clint1, Nbea, Smtnl2, Rin3, Dclk1, and Slc24a4.

Host-pathogen interaction in Toxoplasma gondii-infected mixed chicken blood cell cultures

Toxoplasma gondii has the ability to infect various nucleated cell types in different hosts. The aim of the present study was to investigate which chicken blood cells were targeted by T. gondii in a mixed blood cell culture similar to in vivo conditions and to evaluate parasite-host cell interactions. The study consisted of two subsequent experiments. In experiment 1, we applied T. gondii tachyzoites (ME49) at a multiplicity of infection of 1 tachyzoite per blood cell and examined parasite replication, cytokine, and inducible nitric oxide synthase (iNOS) mRNA expression between 1 h and 48 h post-infection (p.i.) by quantitative PCR. By using T. gondii RH-GFP tachyzoites expressing the green fluorescent protein (GFP) in experiment 2, we aimed for visualizing infected cells by confocal laser scanning microscopy (CLSM) and flow cytometric analysis at 24 h p.i. The parasite replication curve showed a massive decrease of parasite stages until 24 h p.i. followed by an approximately plateau phase. We observed mainly significantly increased iNOS mRNA expression levels in T. gondii-infected culture compared to uninfected cells. Flow cytometry and CLSM data confirmed monocytes/macrophages as main target cells for T. gondii. Moreover, different lymphocytes like B cells and cytotoxic T cells seem to be targeted to a low extent. Our findings indicate that monocytes/macrophages play a key role during T. gondii infection in chicken as host cells and triggering of immune response. To the best of our knowledge, this is the first report of a mixed chicken blood cell culture experimentally infected with T. gondii.

Prediction of the chemical body composition of Nellore and crossbreed bulls

Young Nellore and crossbreed bulls were comparatively slaughtered to generate equation models for predicting the chemical composition of the empty body and carcass from the chemical composition of the Hankins and Howe section (; ). Data were collected from 236 animals from different genetic groups: Nellore, one-half Canchim + one-half Nellore, one-half Angus + one-half Nellore, and one-half Simmental + one-half Nellore, with 48 baseline animals (BW range from 218 to 433 kg) and 188 animals finished in the feedlot (BW range from 356 to 618 kg). The chemical composition prediction equation model was developed for all genetic groups using stepwise regression analysis. Across all animals, the percentages of water and ether extract in the HH section were highly correlated ( < 0.001) with the percentages in the carcass ( = 0.911 and = 0.901, respectively, for water content of the carcass [HOC] and = 0.921 and = 0.921, respectively, for ether extract content of the carcass [EEC]) and empty body ( = 0.937 and = 0.926, respectively, for water content of the empty body [HOEB] and = 0.935 and = 0.939, respectively, for ether extract content of the empty body [EEEB]). The best prediction models were for the traits of empty body weight, HOEB, EEEB, HOC, and EEC. Determination coefficients for predicting the dependent variables obtained from the carcass composition were lower than those obtained from the empty body composition. It was concluded that the chemical composition of the empty body and the carcass can be predicted from the composition of the HH section, using a general equation for different genetic groups.

Variable Susceptibility to Cigarette Smoke-Induced Emphysema in 34 Inbred Strains of Mice Implicates Abi3bp in Emphysema Susceptibility

Chronic obstructive pulmonary disease (COPD) is caused by a complex interaction of environmental exposures, most commonly cigarette smoke, and genetic factors. Chronic cigarette smoke exposure in the mouse is a commonly used animal model of COPD. We aimed to expand our knowledge about the variable susceptibility of inbred strains to this model and test for genetic variants associated with this trait. To that end, we sought to measure differential susceptibility to cigarette smoke-induced emphysema in the mouse, identify genetic loci associated with this quantitative trait, and find homologous human genes associated with COPD. Alveolar chord length (CL) in 34 inbred strains of mice was measured after 6 months of exposure to cigarette smoke. After testing for association, we connected a murine candidate locus to a published meta-analysis of moderate-to-severe COPD. We identified deleterious mutations in a candidate gene in silico and measured gene expression in extreme strains. A/J was the most susceptible strain in our survey (Δ CL 7.0 ± 2.2 μm) and CBA/J was the least susceptible (Δ CL -0.3 ± 1.2 μm). By integrating mouse and human genome-wide scans, we identified the candidate gene Abi3bp. CBA/J mice harbor predicted deleterious variants in Abi3bp, and expression of the gene differs significantly between CBA/J and A/J mice. This is the first report of susceptibility to cigarette smoke-induced emphysema in 34 inbred strains of mice, and Abi3bp is identified as a potential contributor to this phenotype.

Effect of the genetic group, production system and sex on the meat quality and sensory traits of beef from crossbred animals

The crossbreeding of two or more breeds from the Bos taurus and Bos indicus species is an alternative for obtaining high-quality meat from animals adapted to tropical climates. Quality and sensory attributes of beef, mainly its tenderness and flavour, are very important with regard to the consumer's point of view. This study aimed to evaluate the physico-chemical and sensory characteristics of crossbred young bulls and heifers, the offspring of Angus or Limousin bulls and 1/2 Angus + 1/2 Nellore or 1/2 Simental + 1/2 Nellore cows that were finished on feedlot or pasture. Meat quality traits (pH, colour, cooking loss, water holding capacity and shear force) and sensory parameters (characteristic beef aroma/flavour intensity, strange aroma/flavour intensity, tenderness and juiciness descriptive attributes, flavour, texture (tenderness) and overall acceptance) were evaluated. The genetic group had an effect on the beef pH, but it was not as relevant as the effect of the combination between the production system and the sex or genetic group, which affected many of the quality and sensory traits.

Genome-Wide Association Mapping of the Antibody Response to Diphtheria, Tetanus and Acellular Pertussis Vaccine in Mice

The objective of the current study was to investigate the genetics of antibody responses to an acellular pertussis vaccine by a genome-wide association study in mice. Female mice of 28 inbred strains received this vaccine at 6, 8, and 12 weeks of age. The antibody titer and avidity of immunoglobulin (Ig) G specific for diphtheria toxin, pertussis toxin, filamentous hemagglutinin and pertactin were measured at 14 and 24 weeks of age. The magnitude, longevity and avidity of IgG differed significantly among mouse strains. There was significant correlation between antigen-specific IgGs for longevity but not for magnitude and avidity. Association mapping and analysis with PolyPhen software identified 6 genetic markers associated with longevity for all 4 antigens, although the expression levels of these genes did not correlate with longevity phenotype. This study provides novel insights into the genetic basis and potential candidate genes for differences in the IgG responses to vaccination.

TCGA Expedition: A Data Acquisition and Management System for TCGA Data

Background

The Cancer Genome Atlas Project (TCGA) is a National Cancer Institute effort to profile at least 500 cases of 20 different tumor types using genomic platforms and to make these data, both raw and processed, available to all researchers. TCGA data are currently over 1.2 Petabyte in size and include whole genome sequence (WGS), whole exome sequence, methylation, RNA expression, proteomic, and clinical datasets. Publicly accessible TCGA data are released through public portals, but many challenges exist in navigating and using data obtained from these sites. We developed TCGA Expedition to support the research community focused on computational methods for cancer research. Data obtained, versioned, and archived using TCGA Expedition supports command line access at high-performance computing facilities as well as some functionality with third party tools. For a subset of TCGA data collected at University of Pittsburgh, we also re-associate TCGA data with de-identified data from the electronic health records. Here we describe the software as well as the architecture of our repository, methods for loading of TCGA data to multiple platforms, and security and regulatory controls that conform to federal best practices.

Results

TCGA Expedition software consists of a set of scripts written in Bash, Python and Java that download, extract, harmonize, version and store all TCGA data and metadata. The software generates a versioned, participant- and sample-centered, local TCGA data directory with metadata structures that directly reference the local data files as well as the original data files. The software supports flexible searches of the data via a web portal, user-centric data tracking tools, and data provenance tools. Using this software, we created a collaborative repository, the Pittsburgh Genome Resource Repository (PGRR) that enabled investigators at our institution to work with all TCGA data formats, and to interrogate these data with analysis pipelines, and associated tools. WGS data are especially challenging for individual investigators to use, due to issues with downloading, storage, and processing; having locally accessible WGS BAM files has proven invaluable.

Conclusion

Our open-source, freely available TCGA Expedition software can be used to create a local collaborative infrastructure for acquiring, managing, and analyzing TCGA data and other large public datasets.

Approaches to Investigating Complex Genetic Traits in a Large-Scale Inbred Mouse Aging Study

Inbred mice are a unique model system for studying aging because of the genetic homogeneity within inbred strains, the short life span of mice relative to humans, and the rich array of analytic tools that are available. A large-scale aging study was conducted on 28 inbred strains representing great genetic diversity to determine, via histopathology, the type and diversity of spontaneous diseases that aging mice develop. A total of 20 885 different diagnoses were made, with an average of 12 diagnoses per mouse in the study. Eighteen inbred strains have had their genomes sequenced, and many others have been partially sequenced to provide large repositories of data on genetic variation among the strains. This vast amount of genomic information can be utilized in genome-wide association studies to find candidate genes that are involved in the pathogenesis of spontaneous diseases. As an illustration, this article presents a genome-wide association study of the genetic associations of age-related intestinal amyloidosis, which implicated 3 candidate genes: translocating chain-associated membrane protein 1 (Tram1); splicing factor 3b, subunit 5 (Sf3b5); and syntaxin 11 (Stx11). Representative photomicrographs are available on the Mouse Tumor Biology Database and Pathbase to serve as a reference when evaluating inbred mice used in other genetic or experimental studies to rule out strain background lesions. Many of the age-related mouse diseases are similar, if not identical, to human diseases; therefore, the genetic discoveries have direct translational benefit.

Genetic determinants of fibro-osseous lesions in aged inbred mice

Fibro-osseous lesions in mice are progressive aging changes in which the bone marrow is replaced to various degrees by fibrovascular stroma and bony trabeculae in a wide variety of bones. The frequency and severity varied greatly among 28 different inbred mouse stains, predominantly affecting females, ranging from 0% for 10 strains to 100% for KK/HlJ and NZW/LacJ female mice. Few lesions were observed in male mice and for 23 of the strains, no lesions were observed in males for any of the cohorts. There were no significant correlations between strain-specific severities of fibro-osseous lesions and ovarian (r=0.11; P=0.57) or endometrial (r=0.03; P=0.89) cyst formation frequency or abnormalities in parathyroid glands. Frequency of fibro-osseous lesions was most strongly associated (P<10(-6)) with genome variations on chromosome (Chr) 8 at 90.6 and 90.8Mb (rs33108071, rs33500669; P=5.0·10(-10), 1.3·10(-6)), Chr 15 at 23.6 and 23.8Mb (rs32087871, rs45770368; P=7.3·10(-7), 2.7·10(-6)), and Chr 19 at 33.2, 33.4, and 33.6Mb (rs311004232, rs30524929, rs30448815; P=2.8·10(-6), 2.8·10(-6), 2.8·10(-6)) in genome-wide association studies (GWAS). The relatively large number of candidate genes identified in the GWAS analyses suggests that this may be an extremely complex polygenic disease. These results indicate that fibro-osseous lesions are surprisingly common in many inbred strains of laboratory mice as they age. While this presents little problem in most studies that utilize young animals, it may complicate aging studies, particularly those focused on bone.

Integrative Mouse and Human Studies Implicate ANGPT1 and ZBTB7C as Susceptibility Genes to Ischemic Injury

BACKGROUND AND PURPOSE

The extent of ischemic injury in response to cerebral ischemia is known to be affected by native vasculature. However, the nonvascular and dynamic vascular responses and their genetic basis are not well understood.

METHODS

We performed a genome-wide association study in 235 mice from 33 inbred strains using the middle cerebral artery occlusion model. Population structure and genetic relatedness were accounted for using the efficient mixed-model association method. Human orthologs to the genes associated with the significant and suggestive single-nucleotide polymorphisms from the mouse strain survey were examined in patients with M1 occlusions admitted with signs and symptoms of acute ischemic stroke.

RESULTS

We identified 4 genome-wide significant and suggestive single-nucleotide polymorphisms to be associated with infarct volume in mice (rs3694965, P=2.17×10(-7); rs31924033, P=5.61×10(-6); rs32249495, P=2.08×10(-7); and rs3677406, P=9.56×10(-6)). rs32249495, which corresponds to angiopoietin-1 (ANGPT1), was also significant in the recessive model in humans, whereas rs1944577, which corresponds to ZBTB7C, was nominally significant in both the additive and dominant genetic models in humans. ZBTB7C was shown to be upregulated in endothelial cells using both in vitro and in vivo models of ischemia.

CONCLUSIONS

Genetic variations of ANGPT1 and ZBTB7C are associated with increased infarct size in both mice and humans. ZBTB7C may modulate the ischemic response via neuronal apoptosis and dynamic collateralization and, in addition to ANGPT1, may serve as potential novel targets for treatments of cerebral ischemia.

Alopecia areata: updates from the mouse perspective

Alopecia areata (AA) is a cell-mediated autoimmune disease that targets actively growing hair follicles in mammals, including humans and mice. Development of the C3H/HeJ spontaneous mouse model AA nearly 20 years ago provided a much needed tool to test the hypotheses and ultimately serve as a preclinical model for drug testing. Discoveries in both human AA patients and the mouse model supported each other and lead to discoveries on the incredibly complex genetic basis of this disease. The discovery that A/J, MRL/MpJ, SJL/J, and SWR/J strains also develop AA now allows genome-wide association mapping studies to expand the list of genes underlying this disease. Potential new targets for unraveling the pathogenesis of AA include the role of retinoic acid metabolism in the severity of disease and hair shaft proteins that may be either the inciting antigen or ultimate target of the immune reaction leading to breakage of the shaft causing clinical alopecia. Comparing these model systems with human and mouse clinical disease, for both discovery and validation of the discoveries, continues to resolve the complex questions surrounding AA.

Personalized medicine for chronic, complex diseases: chronic obstructive pulmonary disease as an example

Chronic, complex diseases represent the majority of healthcare utilization and spending in the USA today. Despite this, therapeutics that account for the heterogeneity of these diseases are lacking, begging for more personalized approaches. Improving our understanding of disease phenotypes through retrospective trials of electronic health record data will enable us to better categorize patients. Increased usage of next-generation sequencing will further our understanding of the genetic variants involved in chronic disease. Utilization of data warehousing will be necessary in order to securely handle, integrate and analyze the large sets of data produced with these methods. Finally, increased use of clinical decision support will enable the return of clinically actionable results that physicians can use to apply these personalized approaches.

Effect of lipid sources with different fatty acid profiles on the intake, performance, and methane emissions of feedlot Nellore steers

The present study was conducted to evaluate the effect of lipids with different fatty acid profiles on the intake, performance, and enteric CH4 emission of Nellore steers. A total of 45 Nellore animals with an average initial BW of 419 ± 11 kg (at 15 ± 2 mo) were distributed in a completely randomized design consisting of 5 treatments and 9 replicates. The roughage feed was maize silage (600 g/kg on a DM basis) plus concentrate (400 g/kg on a DM basis). The dietary treatments were as follows: without additional fat (WF), palm oil (PO), linseed oil (LO), protected fat (PF; Lactoplus), and whole soybeans (WS). The lipid source significantly affected (P < 0.05) nutrient intake. The greatest intakes of DM, OM, and CP were observed in the animals that were fed the WF or PF diets, and the lowest intakes were observed in the animals that were fed the PO diet. Intake of NDF decreased (P < 0.05) with the addition of PO. Enteric methane emission (g/kg DMI) was reduced by an average of 30% when the animals were fed diets containing WS, LO, and PO (P < 0.05), and these diets caused a larger reduction in the energy loss in the form of methane compared to those without added fat and with added PF (3.3 vs. 4.7%). The different fatty acid profiles did not affect the backfat thickness or the loin eye area of the animals (P > 0.05). However, animals fed PO displayed lower daily weight gain (0.36 kg/d), feed efficiency (0.08 kg ADG/kg DM), HCW (245 kg), and hot yield percentage (52.6%) compared to animals that were fed the other diets. Therefore, PO compared to the other lipid sources used in this study reduces intake, performance, feed efficiency, and carcass yield. Therefore, PO is not suggested for feedlot-finished animals.

Mouse models for pseudoxanthoma elasticum: genetic and dietary modulation of the ectopic mineralization phenotypes

Pseudoxanthoma elasticum (PXE), a heritable ectopic mineralization disorder, is caused by mutations in the ABCC6 gene. Null mice (Abcc6^−/−) recapitulate the genetic, histopathologic and ultrastructural features of PXE, and they demonstrate early and progressive mineralization of vibrissae dermal sheath, which serves as a biomarker of the overall mineralization process. Recently, as part of a mouse aging study at The Jackson Laboratory, 31 inbred mouse strains were necropsied, and two of them, KK/HlJ and 129S1/SvImJ, were noted to have vibrissae dermal mineralization similar to Abcc6^−/− mice. These two strains were shown to harbor a single nucleotide polymorphism (rs32756904) in the Abcc6 gene, which resulted in out-of-frame splicing and marked reduction in ABCC6 protein expression in the liver of these mice. The same polymorphism is present in two additional mouse strains, DBA/2J and C3H/HeJ, with similar reduction in Abcc6 protein levels, yet these mice did not demonstrate tissue mineralization when kept on standard rodent diet. However, all four mouse strains, when placed on experimental diet enriched in phosphate and low in magnesium, developed extensive ectopic mineralization. These results indicate that the genetic background of mice and the mineral composition of their diet can profoundly modulate the ectopic mineralization process predicated on mutations in the Abcc6 gene. These mice provide novel model systems to study the pathomechanisms and the reasons for strain background on phenotypic variability of PXE.

Functional genomic assessment of phosgene-induced acute lung injury in mice

In this study, a genetically diverse panel of 43 mouse strains was exposed to phosgene and genome-wide association mapping performed using a high-density single nucleotide polymorphism (SNP) assembly. Transcriptomic analysis was also used to improve the genetic resolution in the identification of genetic determinants of phosgene-induced acute lung injury (ALI). We prioritized the identified genes based on whether the encoded protein was previously associated with lung injury or contained a nonsynonymous SNP within a functional domain. Candidates were selected that contained a promoter SNP that could alter a putative transcription factor binding site and had variable expression by transcriptomic analyses. The latter two criteria also required that ≥10% of mice carried the minor allele and that this allele could account for ≥10% of the phenotypic difference noted between the strains at the phenotypic extremes. This integrative, functional approach revealed 14 candidate genes that included Atp1a1, Alox5, Galnt11, Hrh1, Mbd4, Phactr2, Plxnd1, Ptprt, Reln, and Zfand4, which had significant SNP associations, and Itga9, Man1a2, Mapk14, and Vwf, which had suggestive SNP associations. Of the genes with significant SNP associations, Atp1a1, Alox5, Plxnd1, Ptprt, and Zfand4 could be associated with ALI in several ways. Using a competitive electrophoretic mobility shift analysis, Atp1a1 promoter (rs215053185) oligonucleotide containing the minor G allele formed a major distinct faster-migrating complex. In addition, a gene with a suggestive SNP association, Itga9, is linked to transforming growth factor β1 signaling, which previously has been associated with the susceptibility to ALI in mice.

Phenotypic characterization of the KK/HlJ inbred mouse strain

Detailed histopathological diagnoses of inbred mouse strains are important for interpreting research results and defining novel models of human diseases. The aim of this study was to histologically detect lesions affecting the KK/HlJ inbred strain. Mice were examined at 6, 12, and 20 months of age and near natural death (ie, moribund mice). Histopathological lesions were quantified by percentage of affected mice per age group and sex. Predominant lesions were mineralization, hyperplasia, and fibro-osseous lesions. Mineralization was most frequently found in the connective tissue dermal sheath of vibrissae, the heart, and the lung. Mineralization was also found in many other organs but to a lesser degree. Hyperplasia was found most commonly in the pancreatic islets, and fibro-osseous lesions were observed in several bones. The percentage of lesions increased with age until 20 months. This study shows that KK/HlJ mice demonstrate systemic aberrant mineralization, with greatest frequency in aged mice. The detailed information about histopathological lesions in the inbred strain KK/HlJ can help investigators to choose the right model and correctly interpret the experimental results.

Mutant Enpp1asj mice as a model for generalized arterial calcification of infancy

Generalized arterial calcification of infancy (GACI), an autosomal recessive disorder, is characterized by early mineralization of blood vessels, often diagnosed by prenatal ultrasound and usually resulting in demise during the first year of life. It is caused in most cases by mutations in the ENPP1 gene, encoding an enzyme that hydrolyzes ATP to AMP and inorganic pyrophosphate, the latter being a powerful anti-mineralization factor. Recently, a novel mouse phenotype was recognized as a result of ENU mutagenesis – those mice developed stiffening of the joints, hence the mutant mouse was named ‘ages with stiffened joints’ (asj). These mice harbor a missense mutation, p.V246D, in the Enpp1 gene. Here we demonstrate that the mutant ENPP1 protein is largely absent in the liver of asj mice, and the lack of enzymatic activity results in reduced inorganic pyrophosphate (PP_i) levels in the plasma, accompanied by extensive mineralization of a number of tissues, including arterial blood vessels. The progress of mineralization is highly dependent on the mineral composition of the diet, with significant shortening of the lifespan on a diet enriched in phosphorus and low in magnesium. These results suggest that the asj mouse can serve as an animal model for GACI.

Integration of mouse and human genome-wide association data identifies KCNIP4 as an asthma gene

Asthma is a common chronic respiratory disease characterized by airway hyperresponsiveness (AHR). The genetics of asthma have been widely studied in mouse and human, and homologous genomic regions have been associated with mouse AHR and human asthma-related phenotypes. Our goal was to identify asthma-related genes by integrating AHR associations in mouse with human genome-wide association study (GWAS) data. We used Efficient Mixed Model Association (EMMA) analysis to conduct a GWAS of baseline AHR measures from males and females of 31 mouse strains. Genes near or containing SNPs with EMMA p-values <0.001 were selected for further study in human GWAS. The results of the previously reported EVE consortium asthma GWAS meta-analysis consisting of 12,958 diverse North American subjects from 9 study centers were used to select a subset of homologous genes with evidence of association with asthma in humans. Following validation attempts in three human asthma GWAS (i.e., Sepracor/LOCCS/LODO/Illumina, GABRIEL, DAG) and two human AHR GWAS (i.e., SHARP, DAG), the Kv channel interacting protein 4 (KCNIP4) gene was identified as nominally associated with both asthma and AHR at a gene- and SNP-level. In EVE, the smallest KCNIP4 association was at rs6833065 (P-value 2.9e-04), while the strongest associations for Sepracor/LOCCS/LODO/Illumina, GABRIEL, DAG were 1.5e-03, 1.0e-03, 3.1e-03 at rs7664617, rs4697177, rs4696975, respectively. At a SNP level, the strongest association across all asthma GWAS was at rs4697177 (P-value 1.1e-04). The smallest P-values for association with AHR were 2.3e-03 at rs11947661 in SHARP and 2.1e-03 at rs402802 in DAG. Functional studies are required to validate the potential involvement of KCNIP4 in modulating asthma susceptibility and/or AHR. Our results suggest that a useful approach to identify genes associated with human asthma is to leverage mouse AHR association data.

Abstract WP258: ZBTB7C Is Associated With Severity Of Infarction In Cerebral Ischemia

Background Stroke is a complex disease that is affected by multiple genetic and environmental factors. We utilize the variability in inbred mouse strains to evaluate the genetic basis of susceptibility to cerebral infarction.

Methods To identify candidate genes that contribute to this variability in susceptibility, we performed a strain survey on 33 inbred strains of mice using a permanent middle cerebral artery occlusion model. Variability in vascular anatomy was determined by examining the circle of Willis in 22 strains of mice. Infarct volume was obtained and a genome-wide association mapping was performed on 118,019 SNPs using efficient mixed-model association (EMMA) to account for population structure and genetic relatedness in inbred mice. Candidate genes from mice were validated in 34 patients with M1 occlusions from the Genes Associated with Stroke Risk and Outcomes Study (GASROS) and the STOP Stroke Study

Results Two SNPs reached genome-wide significance (rs32249495 p=2.08x10-7 and rs3694965 p=2.17x10-7) and two were suggestive (rs31924033 5.61x10-6 and rs3677406 9.46x10-6). Thirty-eight genes were identified to be within 500kb of these four SNPs, corresponding to twenty-four orthologous human genes. SNPs associated with the human orthologs were validated in patients with M1 occlusions. Of these, one SNP (rs1944586, p=1.06x10-4) corresponding to the ZBTB7C gene was significant after adjusting for multiple testing. In vitro analysis demonstrated upregulation of ZBTB7C expression in endothelial cells under hypoxic conditions.

Conclusion ZBTB7C may be part of a novel genetic pathway that modulates the severity of cerebral infarction and may serve as a new target for therapeutic intervention in cerebral ischemia.

Experimentelle 5-Aminolävulinsäure – induzierte photodynamische Therapie (ALA-PDT) oraler Karzinome

AIMS

Of our own patients suffering from oral squamous cell carcinoma (OSCC), 96% possessed a 5-aminolevulinic acid (ALA)-induced tumor fluorescence. Consequently, the ALA-induced fluorescence of OSCC is suggested as an ideal tool for selective photodynamic therapy (PDT). The aim of the study was to demonstrate selective tumor damage and to analyze the cell death mode (apoptosis vs. necrosis) of OSCC cells in cell culture and in solid, deeply invasive xenotransplants in immunodeficient nude mice using intratumoral laser illumination.

MATERIAL AND METHODS

For ALA-PDT, laser light (635 nm, 0.75 W, 10 min, cooled application system) was used intratumorally as well as in cell culture. The therapeutic response was controlled by histology and immunohistochemistry (Ki-67 index). The apoptosis was evaluated by the TUNEL method and in vitro by flow cytometry. Mutations in the apoptosis-controlling p53 gene were investigated by direct genomic sequencing.

RESULTS AND CONCLUSIONS

1. Although all OSCC exhibited an ALA-induced fluorescence in vivo, the evaluation of the cell lines showed differences in intensity of the ALA-induced fluorescence. This points to a different sensitivity of OSCC for ALA-PDT. 2. The use of a cooled laser light application system allowed intratumoral radiation and treatment of deeply invasive OSCC regions. 3. The cytotoxic effect of ALA-PDT in OSCC is evidenced by a diminution of proliferative activity and necrosis but not by apoptosis. 4. Functional mutations within the p53 gene were considered a possible reason for the absence of apoptosis induction by ALA-PDT.

Emerging genetics of COPD

Since the discovery of alpha-1 antitrypsin in the early 1960s, several new genes have been suggested to play a role in chronic obstructive pulmonary disease (COPD) pathogenesis. Yet, in spite of those advances, much about the genetic basis of COPD still remains to be discovered. Unbiased approaches, such as genome-wide association (GWA) studies, are critical to identify genes and pathways and to verify suggested genetic variants. Indeed, most of our current understanding about COPD candidate genes originates from GWA studies. Experiments in form of cross-study replications and advanced meta-analyses have propelled the field towards unravelling details about COPD's pathogenesis. Here, we review the discovery of genetic variants in association with COPD phenotypes by discussing the available approaches and current findings. Limitations of current studies are considered and future directions provided.

Early gene expression differences in inbred mouse strains with susceptibility to pulmonary adenomas

Lung cancer is the most common cause of cancer-related deaths in both men and women, and effective preventatives are rare due to the difficulty of early detection. Specific gene expression signatures have been identified in individuals that already developed lung cancer. To identify if gene expression differences could be detected in individuals before the onset of the disease, we obtained lung tissues for microarray analysis from young, healthy mice of 9 inbred strains with known differences in their susceptibility to spontaneous pulmonary adenomas when aged. We found that the most common differentially expressed genes among all possible 36 strain comparisons showed significant associations with cancer- and inflammation-related processes. Significant expression differences between susceptible and resistant strains were detected for Aldh3a1, Cxcr1 and 7, Dpt, and Nptx1-genes with known cancer-related functions, and Cd209, Cxcr1 and 7, and Plag2g1b-genes with known inflammatory-related functions. Whereas Aldh3a1, Cd209, Dpt, and Pla2g1b had increased expression, Cxcr1 and 7, and Nptx1 had decreased expression in strains susceptible to pulmonary adenomas. Thus, our study shows that expression differences between susceptible and resistant strains can be detected in young and healthy mice without manifestation of pulmonary adenomas and, thus, may provide an opportunity of early detection. Finally, the identified genes have previously been reported for human non-small cell lung cancer suggesting that molecular pathways may be shared between these two cancer types.

A major X-linked locus affects kidney function in mice

Chronic kidney disease is a common disease with increasing prevalence in the western population. One common reason for chronic kidney failure is diabetic nephropathy. Diabetic nephropathy and hyperglycemia are characteristics of the mouse inbred strain KK/HlJ, which is predominantly used as a model for metabolic syndrome due to its inherited glucose intolerance and insulin resistance. We used KK/HlJ, an albuminuria-sensitive strain, and C57BL/6J, an albuminuria-resistant strain, to perform a quantitative trait locus (QTL) cross to identify the genetic basis for chronic kidney failure. Albumin-creatinine ratio (ACR) was measured in 130 F2 male offspring. One significant QTL was identified on chromosome (Chr) X and four suggestive QTL were found on Chrs 6, 7, 12, and 13. Narrowing of the QTL region was focused on the X-linked QTL and performed by incorporating genotype and expression analyses for genes located in the region. From the 485 genes identified in the X-linked QTL region, a few candidate genes were identified using a combination of bioinformatic evidence based on genomic comparison of the parental strains and known function in urine homeostasis. Finally, this study demonstrates the significance of the X chromosome in the genetic determination of albuminuria.

Phosphodiesterase 2 inhibitors promote axonal outgrowth in organotypic slice co-cultures

The development of appropriate models assessing the potential of substances for regeneration of neuronal circuits is of great importance. Here, we present procedures to analyze effects of substances on fiber outgrowth based on organotypic slice co-cultures of the nigrostriatal dopaminergic system in combination with biocytin tracing and tyrosine hydroxylase labeling and subsequent automated image quantification. Selected phosphodiesterase inhibitors (PDE-Is) were studied to identify their potential growth-promoting capacities. Immunohistochemical methods were used to visualize developing fibers in the border region between ventral tegmental area/substantia nigra co-cultivated with the striatum as well as the cellular expression of PDE2A and PDE10. The quantification shows a significant increase of fiber density in the border region induced by PDE2-Is (BAY60-7550; ND7001), comparable with the potential of the nerve growth factor and in contrast to PDE10-I (MP-10). Analysis of tyrosine hydroxylase-positive fibers indicated a significant increase after treatment with BAY60-7550 and nerve growth factor in relation to dimethyl sulfoxide. Additionally, a dose-dependent increase of intracellular cGMP levels in response to the applied PDE2-Is in PDE2-transfected HEK293 cells was found. In summary, our findings show that PDE2-Is are able to significantly promote axonal outgrowth in organotypic slice co-cultures, which are a suitable model to assess growth-related effects in neuro(re)generation.