Unveiling the Therapeutic Potential of Non-Coding RNAs in Stroke-Induced Tissue Regeneration.

Stroke is a major contributor to mortality and impairment on a global scale, with few effective treatments available. Aberrant expression of various non-coding RNAs (ncRNAs) has been identified after stroke onset, impacting neurogenesis, angiogenesis, apoptosis, and autophagy. The roles and mechanisms of ncRNAs hold great promise for future ischemic stroke treatments, as they could modify stroke impact and course on a well-controllable molecular level. Exploring the functions and underlying mechanisms of ncRNAs after stroke has the potential to unveil novel therapeutic targets for the treatment of stroke and may also pave the way toward novel and more precise diagnostic options for stroke and stroke outcomes. This review emphasizes the importance of ncRNAs in the treatment of stroke and their potential as therapeutic targets.

MCC950 reduces autophagy and improves cognitive function by inhibiting NLRP3-dependent neuroinflammation in a rat model of Alzheimer's disease.

Alzheimer's disease (AD) is the seventh most common cause of mortality and one of the major causes of disability and vulnerability in the elderly. AD is characterized by gradual cognitive deterioration, the buildup of misfolded amyloid beta (Aß) peptide, and the generation of neurofibrillary tangles. Despite enormous scientific progress, there is no effective cure for AD. Thus, exploring new treatment options to stop AD or at least slow down its progress is important. In this study, we investigated the potential therapeutic effects of MCC950 on NLRP3-mediated inflammasome-driven inflammation and autophagy in AD. Rats treated with streptozotocin (STZ) exhibited simultaneous activation of the NLRP3 inflammasome and autophagy, as confirmed by Western blot, immunofluorescence, and co-immunoprecipitation analyses. MCC950, a specific NLRP3 inhibitor, was intraperitoneally administered (50 mg/kg body weight) to rats with AD-like symptoms induced by intracerebroventricular STZ injections (3 mg/kg body weight). MCC950 effectively suppressed STZ-induced cognitive impairment and anxiety by inhibiting NLRP3-dependent neuroinflammation. Moreover, our findings indicate that MCC950 exerts neuroprotective effects by attenuating autophagy in neuronal cells. The inhibiting effects of MCC950 on inflammasome activation and autophagy were reproduced in vitro, provding further mechansistic insights into MCC950 therapeutic action. Our findings suggest that MCC950 impedes the progression of AD and may also improve cognitive function through the mitigation of autophagy and NLRP3 inflammasome inhibition.

The association between air pollutant exposure and cerebral small vessel disease imaging markers with modifying effects of PRS-defined genetic susceptibility.

Studies have highlighted a possible link between air pollution and cerebral small vessel disease (CSVD) imaging markers. However, the exact association and effects of polygenic risk score (PRS) defined genetic susceptibility remains unclear. This cross-sectional study used data from the UK Biobank. Participants aged 40-69 years were recruited between the year 2006 and 2010. The annual average concentrations of NOX, NO2, PM2.5, PM2.5-10, PM2.5 absorbance, and PM10, were estimated, and joint exposure to multiple air pollutants was reflected in the air pollution index (APEX). Air pollutant exposure was classified into the low (T1), intermediate (T2), and high (T3) tertiles. Three CSVD markers were used: white matter hyper-intensity (WMH), mean diffusivity (MD), and fractional anisotropy (FA). The first principal components of the MD and FA measures in the 48 white matter tracts were analysed. The sample consisted of 44,470 participants from the UK Biobank. The median (T1-T3) concentrations of pollutants were as follows: NO2, 25.5 (22.4-28.7) µg/m3; NOx, 41.3 (36.2-46.7) µg/m3; PM10, 15.9 (15.4-16.4) µg/m3; PM2.5, 9.9 (9.5-10.3) µg/m3; PM2.5 absorbance, 1.1 (1.0-1.2) per metre; and PM2.5-10, 6.1 (5.9-6.3) µg/m3. Compared with the low group, the high group's APEX, NOX, and PM2.5 levels were associated with increased WMH volumes, and the estimates (95 %CI) were 0.024 (0.003, 0.044), 0.030 (0.010, 0.050), and 0.032 (0.011, 0.053), respectively, after adjusting for potential confounders. APEX, PM10, PM2.5 absorbance, and PM2.5-10 exposure in the high group were associated with increased FA values compared to that in the low group. Sex-specific analyses revealed associations only in females. Regarding the combined associations of air pollutant exposure and PRS-defined genetic susceptibility with CSVD markers, the associations of NO2, NOX, PM2.5, and PM2.5-10 with WMH were more profound in females with low PRS-defined genetic susceptibility, and the associations of PM10, PM2.5, and PM2.5 absorbance with FA were more profound in females with higher PRS-defined genetic susceptibility. Our study demonstrated that air pollutant exposure may be associated with CSVD imaging markers, with females being more susceptible, and that PRS-defined genetic susceptibility may modify the associations of air pollutants.

Most Promising Approaches to Improve Stroke Outcomes: The Stroke Treatment Academic Industry Roundtable XII Workshop.

The Stroke Treatment Academic Industry Roundtable XII included a workshop to discuss the most promising approaches to improve outcome from acute stroke. The workshop brought together representatives from academia, industry, and government representatives. The discussion examined approaches in 4 epochs: pre-reperfusion, reperfusion, post-reperfusion, and access to acute stroke interventions. The participants identified areas of priority for developing new and existing treatments and approaches to improve stroke outcomes. Although many advances in acute stroke therapy have been achieved, more work is necessary for reperfusion therapies to benefit the most possible patients. Prioritization of promising approaches should help guide the use of resources and investigator efforts.

Priorities for Advancements in Neuroimaging in the Diagnostic Workup of Acute Stroke.

STAIR XII (12th Stroke Treatment Academy Industry Roundtable) included a workshop to discuss the priorities for advancements in neuroimaging in the diagnostic workup of acute ischemic stroke. The workshop brought together representatives from academia, industry, and government. The participants identified 10 critical areas of priority for the advancement of acute stroke imaging. These include enhancing imaging capabilities at primary and comprehensive stroke centers, refining the analysis and characterization of clots, establishing imaging criteria that can predict the response to reperfusion, optimizing the Thrombolysis in Cerebral Infarction scale, predicting first-pass reperfusion outcomes, improving imaging techniques post-reperfusion therapy, detecting early ischemia on noncontrast computed tomography, enhancing cone beam computed tomography, advancing mobile stroke units, and leveraging high-resolution vessel wall imaging to gain deeper insights into pathology. Imaging in acute ischemic stroke treatment has advanced significantly, but important challenges remain that need to be addressed. A combined effort from academic investigators, industry, and regulators is needed to improve imaging technologies and, ultimately, patient outcomes.

Cell-therapy for Parkinson's disease: a systematic review and meta-analysis.

BACKGROUND: Cell-based strategies focusing on replacement or protection of dopaminergic neurons have been considered as a potential approach to treat Parkinson's disease (PD) for decades. However, despite promising preclinical results, clinical trials on cell-therapy for PD reported mixed outcomes and a thorough synthesis of these findings is lacking. We performed a systematic review and meta-analysis to evaluate cell-therapy for PD patients. METHODS: We systematically identified all clinical trials investigating cell- or tissue-based therapies for PD published before July 2023. Out of those, studies reporting transplantation of homogenous cells (containing one cell type) were included in meta-analysis. The mean difference or standardized mean difference in quantitative neurological scale scores before and after cell-therapy was analyzed to evaluate treatment effects. RESULTS: The systematic literature search revealed 106 articles. Eleven studies reporting data from 11 independent trials (210 patients) were eligible for meta-analysis. Disease severity and motor function evaluation indicated beneficial effects of homogenous cell-therapy in the 'off' state at 3-, 6-, 12-, or 24-month follow-ups, and for motor function even after 36 months. Most of the patients were levodopa responders (61.6-100% in different follow-ups). Cell-therapy was also effective in improving the daily living activities in the 'off' state of PD patients. Cells from diverse sources were used and multiple transplantation modes were applied. Autografts did not improve functional outcomes, while allografts exhibited beneficial effects. Encouragingly, both transplantation into basal ganglia and to areas outside the basal ganglia were effective to reduce disease severity. Some trials reported adverse events potentially related to the surgical procedure. One confirmed and four possible cases of graft-induced dyskinesia were reported in two trials included in this meta-analysis. CONCLUSIONS: This meta-analysis provides preliminary evidence for the beneficial effects of homogenous cell-therapy for PD, potentially to the levodopa responders. Allogeneic cells were superior to autologous cells, and the effective transplantation sites are not limited to the basal ganglia. PROSPERO registration number: CRD42022369760.

Oxidative Stress-induced Autophagy Compromises Stem Cell Viability.

Stem cell therapies have emerged as a promising treatment strategy for various diseases characterized by ischemic injury such as ischemic stroke. Cell survival after transplantation remains a critical issue. We investigated the impact of oxidative stress, being typically present in ischemically challenged tissue, on human dental pulp stem cells (hDPSC) and human mesenchymal stem cells (hMSC). We used oxygen-glucose deprivation (OGD) to induce oxidative stress in hDPSC and hMSC. OGD-induced generation of O2•- or H2O2 enhanced autophagy by inducing the expression of activating molecule in BECN1-regulated autophagy protein 1 (Ambra1) and Beclin1 in both cell types. However, hDPSC and hMSC pre-conditioning using reactive oxygen species (ROS) scavengers significantly repressed the expression of Ambra1 and Beclin1 and inactivated autophagy. O2•- or H2O2 acted upstream of autophagy, and the mechanism was unidirectional. Furthermore, our findings revealed ROS-p38-Erk1/2 involvement. Pre-treatment with selective inhibitors of p38 and Erk1/2 pathways (SB202190 and PD98059) reversed OGD effects on the expression of Ambra1 and Beclin1, suggesting that these pathways induced oxidative stress-mediated autophagy. SIRT3 depletion was found to be associated with increased oxidative stress and activation of p38 and Erk1/2 MAPKs pathways. Global ROS inhibition by NAC or a combination of polyethylene glycol-superoxide dismutase (PEG-SOD) and polyethylene glycol-catalase (PEG-catalase) further confirmed that O2•- or H2O2 or a combination of both impacts stems cell viability by inducing autophagy. Furthermore, autophagy inhibition by 3-methyladenine (3-MA) significantly improved hDPSC viability. These findings contribute to a better understanding of post-transplantation hDPSC and hMSC death and may deduce strategies to minimize therapeutic cell loss under oxidative stress.

Focused Update on Stroke Neuroimmunology: Current Progress in Preclinical and Clinical Research and Recent Mechanistic Insight.

Local and systemic inflammation contribute significantly to stroke risk factors as well as determining stroke impact and outcome. Previously being considered as an immuno-privileged domain, the central nervous system is now recognized for multiple and complex interactions with the immune system in health and disease. The sterile inflammatory response emerging after ischemic stroke is a major pathophysiological hallmark and considered to be a promising therapeutic target. Even (mal)adaptive immune responses following stroke, potentially contributing to long-term impact and outcome, are increasingly discussed. However, the complex interaction between the central nervous and the immune system are only partially understood, placing neuroimmunological investigations at the forefront of preclinical and clinical research. This Focused Update summarizes current knowledge in stroke neuroimmunology across all relevant disciplines and discusses major advances as well as recent mechanistic insights. Specifically, neuroimmunological processes and neuroinflammation following ischemic are discussed in the context of blood-brain barrier dysfunction, microglia activation, thromboinflammation, and sex differences in poststroke neuroimmunological responses. The Focused Update further highlights advances in neuroimaging and experimental treatments to visualize and counter neuroinflammatory consequences of ischemic stroke.

Subacute AMD3100 Treatment Is Not Efficient in Neonatal Hypoxic-Ischemic Rats.

BACKGROUND AND PURPOSE: Despite the advances in treating neonatal hypoxic-ischemic encephalopathy (HIE) with induced hypothermia, the rates of severe disability are still high among survivors. Preclinical studies have indicated that cell therapies with hematopoietic stem/progenitor cells could improve neurological outcomes in HIE. In this study, we investigated whether the administration of AMD3100, a CXCR4 antagonist that mobilizes hematopoietic stem/progenitor cells into the circulation, has therapeutic effects in HIE. METHODS: P10 Wistar rats of both sexes were subjected to right common carotid artery occlusion or sham procedure, and then were exposed to hypoxia for 120 minutes. Two subcutaneous injections of AMD3100 or vehicle were given on the third and fourth day after HIE. We first assessed the interindividual variability in brain atrophy after experimental HIE and vehicle treatment in a small cohort of rats. Based on this exploratory analysis, we designed and conducted an experiment to test the efficacy of AMD3100. Brain atrophy on day 21 after HIE was defined as the primary end point. Secondary efficacy end points were cognitive (T-water maze) and motor function (rotarod) on days 17 and 18 after HIE, respectively. RESULTS: AMD3100 did not decrease the brain atrophy in animals of either sex. Cognitive impairments were not observed in the T-water maze, but male hypoxic-ischemic animals exhibited motor coordination deficits on the rotarod, which were not improved by AMD3100. A separate analysis combining data from animals of both sexes also revealed no evidence of the effectiveness of AMD3100 treatment. CONCLUSIONS: These results indicate that the subacute treatment with AMD3100 does not improve structural and functional outcomes in a rat HIE model.

Adenosine A1R/A3R (Adenosine A1 and A3 Receptor) Agonist AST-004 Reduces Brain Infarction in a Nonhuman Primate Model of Stroke.

BACKGROUND AND PURPOSE: Treatment with A1R/A3R (adenosine A1 and A3 receptor) agonists in rodent models of acute ischemic stroke results in significantly reduced lesion volume, indicating activation of adenosine A1R or A3R is cerebroprotective. However, dosing and timing required for cerebroprotection has yet to be established, and whether adenosine A1R/A3R activation will lead to cerebroprotection in a gyrencephalic species has yet to be determined. METHODS: The current study used clinical study intervention timelines in a nonhuman primate model of transient, 4-hour middle cerebral artery occlusion to investigate a potential cerebroprotective effect of the dual adenosine A1R/A3R agonist AST-004. Bolus and then 22 hours intravenous infusion of AST-004 was initiated 2 hours after transient middle cerebral artery occlusion. Primary outcome measures included lesion volume, lesion growth kinetics, penumbra volume as well as initial pharmacokinetic-pharmacodynamic relationships measured up to 5 days after transient middle cerebral artery occlusion. Secondary outcome measures included physiological parameters and neurological function. RESULTS: Administration of AST-004 resulted in rapid and statistically significant decreases in lesion growth rate and total lesion volume. In addition, penumbra volume decline over time was significantly less under AST-004 treatment compared with vehicle treatment. These changes correlated with unbound AST-004 concentrations in the plasma and cerebrospinal fluid as well as estimated brain A1R and A3R occupancy. No relevant changes in physiological parameters were observed during AST-004 treatment. CONCLUSIONS: These findings suggest that administration of AST-004 and combined A1R/A3R agonism in the brain are efficacious pharmacological interventions in acute ischemic stroke and warrant further clinical evaluation.

Comparison of Large Animal Models for Acute Ischemic Stroke: Which Model to Use?

Translation of acute ischemic stroke research to the clinical setting remains limited over the last few decades with only one drug, recombinant tissue-type plasminogen activator, successfully completing the path from experimental study to clinical practice. To improve the selection of experimental treatments before testing in clinical studies, the use of large gyrencephalic animal models of acute ischemic stroke has been recommended. Currently, these models include, among others, dogs, swine, sheep, and nonhuman primates that closely emulate aspects of the human setting of brain ischemia and reperfusion. Species-specific characteristics, such as the cerebrovascular architecture or pathophysiology of thrombotic/ischemic processes, significantly influence the suitability of a model to address specific research questions. In this article, we review key characteristics of the main large animal models used in translational studies of acute ischemic stroke, regarding (1) anatomy and physiology of the cerebral vasculature, including brain morphology, coagulation characteristics, and immune function; (2) ischemic stroke modeling, including vessel occlusion approaches, reproducibility of infarct size, procedural complications, and functional outcome assessment; and (3) implementation aspects, including ethics, logistics, and costs. This review specifically aims to facilitate the selection of the appropriate large animal model for studies on acute ischemic stroke, based on specific research questions and large animal model characteristics.

Gap junction-mediated cell-cell interaction between transplanted mesenchymal stem cells and vascular endothelium in stroke.

We have shown previously that transplanted bone marrow mononuclear cells (BM-MNC), which are a cell fraction rich in hematopoietic stem cells, can activate cerebral endothelial cells via gap junction-mediated cell-cell interaction. In the present study, we investigated such cell-cell interaction between mesenchymal stem cells (MSC) and cerebral endothelial cells. In contrast to BM-MNC, for MSC we observed suppression of vascular endothelial growth factor uptake into endothelial cells and transfer of glucose from endothelial cells to MSC in vitro. The transfer of such a small molecule from MSC to vascular endothelium was subsequently confirmed in vivo and was followed by suppressed activation of macrophage/microglia in stroke mice. The suppressive effect was absent by blockade of gap junction at MSC. Furthermore, gap junction-mediated cell-cell interaction was observed between circulating white blood cells and MSC. Our findings indicate that gap junction-mediated cell-cell interaction is one of the major pathways for MSC-mediated suppression of inflammation in the brain following stroke and provides a novel strategy to maintain the blood-brain barrier in injured brain. Furthermore, our current results have the potential to provide a novel insight for other ongoing clinical trials that make use of MSC transplantation aiming to suppress excess inflammation, as well as other diseases such as COVID-19 (coronavirus disease 2019).

Top Priorities for Cerebroprotective Studies-A Paradigm Shift: Report From STAIR XI.

Despite years of basic research and pioneering clinical work, ischemic stroke remains a major public health concern. Prior STAIR (Stroke Treatment Academic Industry Roundtable) conferences identified both failures of clinical trial design and failures in preclinical assessment in developing putative ischemic stroke treatments. At STAIR XI, participants in workshop no. 1 Top Priorities for Neuroprotection sought to redefine the neuroprotection paradigm and given the paucity of evidence underlying preclinical assessment, offer consensus-based recommendations. STAIR proposes the term brain cytoprotection or cerebroprotection to replace the term neuroprotection when the intention of an investigation is to demonstrate that a new, candidate treatment benefits the entire brain. Although "time is still brain," tissue imaging techniques have been developed to identify patients with both predicted core injury and penumbral, salvageable brain tissue, regardless of time after stroke symptom onset. STAIR XI workshop participants called this imaging approach a tissue window to select patients for recanalization. Elements of the neurovascular unit show differential vulnerability evolving over differing time scales in different brain regions. STAIR proposes the term target window to suggest therapies that target the different elements of the neurovascular unit at different times. Based on contemporary principles of rigor and transparency, the workshop updated, revised, and enhanced the STAIR preclinical recommendations for developing new treatments in 2 phases: an exploratory qualification phase and a definitive validation phase. For new, putative treatments, investigators should carefully characterize the mechanism of action, the pharmacokinetics/pharmacodynamics, demonstrate target engagement, and confirm penetration through the blood-brain barrier. Before clinical trials, testing of candidate molecules in stroke models could proceed in a comprehensive manner using animals of both sexes and to include significant variables such as age and comorbid conditions. Comprehensive preclinical assessment might include multicenter, collaborative testing, for example, network trials. In the absence of a proven cerebroprotective agent to use as a gold standard, however, it remains speculative whether such comprehensive preclinical assessment can effectively predict clinical outcome.

Bone Marrow Mononuclear Cells Activate Angiogenesis via Gap Junction-Mediated Cell-Cell Interaction.

Background and Purpose- Bone marrow mononuclear cells (BM-MNCs) are a rich source of hematopoietic stem cells and have been widely used in experimental therapies for patients with ischemic diseases. Activation of angiogenesis is believed to be one of major BM-MNC mode of actions, but the essential mechanism by which BM-MNCs activate angiogenesis have hitherto been elusive. The objective of this study is to reveal the mechanism how BM-MNCs activate angiogenesis. Methods- We have evaluated the effect of direct cell-cell interaction between BM-MNC and endothelial cell on uptake of VEGF (vascular endothelial growth factor) into endothelial cells in vitro. Cerebral ischemia model was used to evaluate the effects of direct cell-cell interaction with transplanted BM-MNC on endothelial cell at ischemic tissue. Results- The uptake of VEGF into endothelial cells was increased by BM-MNC, while being inhibited by blockading the gap junction. Low-molecular-weight substance was transferred from BM-MNC into endothelial cells via gap junctions in vivo, followed by increased expression of hypoxia-inducible factor-1α and suppression of autophagy in endothelial cells. The concentration of glucose in BM-MNC cytoplasm was significantly higher than in endothelial cells, and transfer of glucose homologue from BM-MNC to endothelial cells was observed. Conclusions- Our findings demonstrated cell-cell interaction via gap junction is the prominent pathway for activation of angiogenesis at endothelial cells after ischemia and provided novel paradigm that energy source supply by stem cell to injured cell is one of the therapeutic mechanisms of cell-based therapy. Visual Overview- An online visual overview is available for this article.

The emergence of dyslexia in the developing brain.

Developmental dyslexia, a severe deficit in literacy learning, is a neurodevelopmental learning disorder. Yet, it is not clear whether existing neurobiological accounts of dyslexia capture potential predispositions of the deficit or consequences of reduced reading experience. Here, we longitudinally followed 32 children from preliterate to school age using functional and structural magnetic resonance imaging techniques. Based on standardised and age-normed reading and spelling tests administered at school age, children were classified as 16 dyslexic participants and 16 controls. This longitudinal design allowed us to disentangle possible neurobiological predispositions for developing dyslexia from effects of individual differences in literacy experience. In our sample, the disorder can be predicted already before literacy learning from auditory cortex gyrification and aberrant downstream connectivity within the speech processing system. These results provide evidence for the notion that dyslexia may originate from an atypical maturation of the speech network that precedes literacy instruction.

Induction of immunological tolerance to myelinogenic glial-restricted progenitor allografts.

The immunological barrier currently precludes the clinical utilization of allogeneic stem cells. Although glial-restricted progenitors have become attractive candidates to treat a wide variety of neurological diseases, their survival in immunocompetent recipients is limited. In this study, we adopted a short-term, systemically applicable co-stimulation blockade-based strategy using CTLA4-Ig and anti-CD154 antibodies to modulate T-cell activation in the context of allogeneic glial-restricted progenitor transplantation. We found that co-stimulation blockade successfully prevented rejection of allogeneic glial-restricted progenitors from immunocompetent mouse brains. The long-term engrafted glial-restricted progenitors myelinated dysmyelinated adult mouse brains within one month. Furthermore, we identified a set of plasma miRNAs whose levels specifically correlated to the dynamic changes of immunoreactivity and as such could serve as biomarkers for graft rejection or tolerance. We put forward a successful strategy to induce alloantigen-specific hyporesponsiveness towards stem cells in the CNS, which will foster effective therapeutic application of allogeneic stem cells.

Clot-Derived Contaminants in Transplanted Bone Marrow Mononuclear Cells Impair the Therapeutic Effect in Stroke.

Background and Purpose- The beneficial effects of bone marrow mononuclear cell (BM-MNC) transplantation in preclinical experimental stroke have been reliably demonstrated. However, only overall modest effects in clinical trials were observed. We have investigated and reported a cause of the discrepancy between the preclinical and clinical studies. Methods- To investigate the possible cause of low efficacy of BM-MNC transplantation in experimental stroke, we have focused on blood clot formation, which is not uncommon in human bone marrow aspirates. To evaluate the effects of clot-derived contaminants in transplanted BM-MNC on stroke outcome, a murine stroke model was used. Results- We show that BM-MNC separated by an automatic cell isolator (Sepax2), which does not have the ability to remove clots, did not attenuate brain atrophy after stroke. In contrast, manually isolated, clot-free BM-MNC exerted therapeutic effects. Clot-derived contaminants were also transplanted intravenously to poststroke mice. We found that the transplanted contaminants were trapped at the peristroke area, which were associated with microglial/macrophage activation. Conclusions- Clot-derived contaminants in transplanted BM-MNC nullify therapeutic effects in experimental stroke. This may explain neutral results in clinical trials, especially in those using automated stem cell separators that lack the ability to remove clot-derived contaminants. Visual Overview- An online visual overview is available for this article.

A stereotaxic breed-averaged, symmetric T2w canine brain atlas including detailed morphological and volumetrical data sets.

Stereotaxic systems and automatic tissue segmentation routines enable neuronavigation as well as reproducible processing of neuroimage datasets. Such systems have been developed for humans, non-human-primates, sheep, and rodents, but not for dogs. Although dogs share important neurofunctional and -anatomical features with humans, and in spite of their importance in translational neuroscience, little is known about the variability of the canine brain morphology and, possibly related, function. Moreover, we lack templates, tissue probability maps (TPM), and stereotaxic brain labels for implementation in standard software utilities such as Statistical Parametric Mapping (SPM). Hence, objective and reproducible, image-based investigations are currently impeded in dogs. We have created a detailed stereotaxic reference frame for dogs including TPM and tissue labels, enabling inter-individual and cross-study neuroimage analysis. T2w datasets were acquired from 16 neurologically inconspicuous dogs of different breeds by 3T MRI. The datasets were averaged after initial preprocessing using linear and nonlinear registration algorithms as implemented in SPM8. TPM for gray (GM) and white matter (WM) as well as cerebrospinal fluid (CSF) were created. Different cortical, subcortical, medullary, and CSF regions were manually labeled to create a spatial binary atlas being aligned with the template. A proof-of-concept for automatic determination of morphological and volumetrical characteristics was performed using additional canine datasets (n = 64) including a subgroup of laboratory beagles (n = 24). Overall, 21 brain regions were labeled using the segmented tissue classes of the brain template. The proof-of-concept trial revealed excellent suitability of the created tools for image processing and subsequent analysis. There was high intra-breed variability in frontal lobe and hippocampus volumes, and noticeable inter-breed corpus callosum volume variation. The T2w brain template provides important, breed-averaged canine brain anatomy features in a spatial standard coordinate system. TPM allows automatic tissue segmentation using SPM and enables unbiased automatic image processing or morphological characterization in different canine breeds. The reported volumetric and morphometric results may serve as a starting point for further research aimed at in vivo analysis of canine brain anatomy and function.

Concise Review: Increasing the Validity of Cerebrovascular Disease Models and Experimental Methods for Translational Stem Cell Research.

Interspecies differences, anatomical and physiological aspects, as wells as simplified study designs contribute to an overestimation of treatment effects and limit the transferability of experimental results into clinical applications. Confounders of cell therapies for cerebrovascular disorders (CVD) include common CVD comorbidities, frequent medications potentially affecting endogenous and transplanted stem cells, as well as age- and immune-system-related effects. All those can contribute to a substantial modeling bias, ultimately limiting the prospective quality of preclinical research programs regarding the clinical value of a particular cell therapy. In this review, we discuss the nature and impact of most relevant confounders. We provide suggestions on how they can be considered to enhance the validity of CVD models in stem cell research. Acknowledging substantial and sometimes surprising effects of housing conditions, chronobiology, and intersex differences will further augment the translational value of animal models. We finally discuss options for the implementation of high-quality functional and imaging readout protocols. Altogether, this might help to gain a more holistic picture about the therapeutic impact of a particular cell therapy for CVD, but also on potential side and off-site effects of the intervention. Stem Cells 2017;35:1141-1153.