Firms' Innovation Strategy under the Shadow of Analyst Coverage

We study the effect of analyst coverage on firms’ innovation strategy and outcome. By considering three different channels that allow firms to innovate: internal R&D, acquisitions of other innovative firms, and investments in corporate venture capital (CVC), we are able to distinguish between the pressure and information effect of analysts. Using the data of US firms from 1990 to 2012, we find evidence that: i) an increase in financial analysts leads firms to cut R&D expenses, and ii) more analyst coverage leads firms to acquire more innovative firms and invest in CVC. We attribute the first result to the effect of analyst pressure, and the second to the informational role of analysts. In line with the previous literature, we also find that analyst coverage has a negative effect on firms’ future patents and citations; however, this negative effect becomes not significant when firms’ in-house R&D spending and external innovation channels are taken into account. We find that more financial analysts encourage firms to make more efficient investments related to innovation, which increase their future patents and citations. We address endogeneity with an instrumental variables approach and a difference-in-differences strategy where exogenous variation in analyst coverage comes from brokerage house mergers

Charge effect of a liposomal delivery system encapsulating simvastatin to treat experimental ischemic stroke in rats

[Background and aims]: Although the beneficial effects of statins on stroke have been widely demonstrated both in experimental studies and in clinical trials, the aim of this study is to prepare and characterize a new liposomal delivery system that encapsulates simvastatin to improve its delivery into the brain. [Materials and methods]: In order to select the optimal liposome lipid composition with the highest capacity to reach the brain, male Wistar rats were submitted to sham or transitory middle cerebral arterial occlusion (MCAOt) surgery and treated (intravenous [IV]) with fluorescent-labeled liposomes with different net surface charges. Ninety minutes after the administration of liposomes, the brain, blood, liver, lungs, spleen, and kidneys were evaluated ex vivo using the Xenogen IVIS® Spectrum imaging system to detect the load of fluorescent liposomes. In a second substudy, simvastatin was assessed upon reaching the brain, comparing free and encapsulated simvastatin (IV) administration. For this purpose, simvastatin levels in brain homogenates from sham or MCAOt rats at 2 hours or 4 hours after receiving the treatment were detected through ultra-high-protein liquid chromatography. [Results]: Whereas positively charged liposomes were not detected in brain or plasma 90 minutes after their administration, neutral and negatively charged liposomes were able to reach the brain and accumulate specifically in the infarcted area. Moreover, neutral liposomes exhibited higher bioavailability in plasma 4 hours after being administered. The detection of simvastatin by ultra-high-protein liquid chromatography confirmed its ability to cross the blood-brain barrier, when administered either as a free drug or encapsulated into liposomes. [Conclusion]: This study confirms that liposome charge is critical to promote its accumulation in the brain infarct after MCAOt. Furthermore, simvastatin can be delivered after being encapsulated. Thus, simvastatin encapsulation might be a promising strategy to ensure that the drug reaches the brain, while increasing its bioavailability and reducing possible side effects.The research leading to these results received funding from the European Union’s Seventh Framework Program (FP7/2007-2013) under grant agreements number 201024 and number 202213 (European Stroke Network). Neurovascular Research Laboratory takes part in the Spanish stroke research network INVICTUS (RD12/0014/0005). This study was partially funded by projects FIS 11/0176 on stroke biomarkers research and EC07/90195 on increasing safety and efficacy of simvastatin neuroprotection.Peer Reviewe

Modeling Stroke in Mice: Transient Middle Cerebral Artery Occlusion via the External Carotid Artery

Stroke is the third most common cause of mortality and the leading cause of acquired adult disability in developed countries. To date, therapeutic options are limited to a small proportion of stroke patients within the first hours after stroke. Novel therapeutic strategies are being extensively investigated, especially to prolong the therapeutic time window. These current investigations include the study of important pathophysiological pathways after stroke, such as post-stroke inflammation, angiogenesis, neuronal plasticity, and regeneration. Over the last decade, there has been increasing concern about the poor reproducibility of experimental results and scientific findings among independent research groups. To overcome the so-called replication crisis, detailed standardized models for all procedures are urgently needed. As an effort within the ImmunoStroke research consortium (https://immunostroke.de/), a standardized mouse model of transient middle cerebral artery occlusion (MCAo) is proposed. This model allows the complete restoration of the blood flow upon removal of the filament, simulating the therapeutic or spontaneous clot lysis that occurs in a large proportion of human strokes. The surgical procedure of this filament stroke model and tools for its functional analysis are demonstrated in the accompanying video

Evaluation and Characterization of Post-Stroke Lung Damage in a Murine Model of Cerebral Ischemia

After stroke and other brain injuries, there is a high incidence of respiratory complications such as pneumonia or acute lung injury. The molecular mechanisms that drive the brain-lung interaction post-stroke have not yet been elucidated. We performed transient middle cerebral artery occlusion (MCAO) and sham surgery on C57BL/6J mice and collected bronchoalveolar lavage fluid (BALF), serum, brain, and lung homogenate samples 24 h after surgery. A 92 proteins-panel developed by Olink Proteomics ® was used to analyze the content in BALF and lung homogenates. MCAO animals had higher protein concentration levels in BALF than sham -controls, but these levels did not correlate with the infarct volume. No alteration in alveolar-capillary barrier permeability was observed. A total of 12 and 14 proteins were differentially expressed between the groups (FDR < 0.1) in BALF and lung tissue homogenates, respectively. Of those, HGF, TGF-α, and CCL2 were identified as the most relevant to this study. Their protein expression patterns were verified by ELISA. This study confirmed that post-stroke lung damage was not associated with increased lung permeability or cerebral ischemia severity. Furthermore, the dysregulation of HGF, TGF-α, and CCL2 in BALF and lung tissue after ischemia could play an important role in the molecular mechanisms underlying stroke-induced lung damage

Integrative Multi-omics Analysis to Characterize Human Brain Ischemia

Stroke is a major cause of death and disability. A better comprehension of stroke pathophysiology is fundamental to reduce its dramatic outcome. The use of high-throughput unbiased omics approaches and the integration of these data might deepen the knowledge of stroke at the molecular level, depicting the interaction between different molecular units. We aimed to identify protein and gene expression changes in the human brain after ischemia through an integrative approach to join the information of both omics analyses. The translational potential of our results was explored in a pilot study with blood samples from ischemic stroke patients. Proteomics and transcriptomics discovery studies were performed in human brain samples from six deceased stroke patients, comparing the infarct core with the corresponding contralateral brain region, unveiling 128 proteins and 2716 genes significantly dysregulated after stroke. Integrative bioinformatics analyses joining both datasets exposed canonical pathways altered in the ischemic area, highlighting the most influential molecules. Among the molecules with the highest fold-change, 28 genes and 9 proteins were selected to be validated in five independent human brain samples using orthogonal techniques. Our results were confirmed for NCDN, RAB3C, ST4A1, DNM1L, A1AG1, A1AT, JAM3, VTDB, ANXA1, ANXA2, and IL8. Finally, circulating levels of the validated proteins were explored in ischemic stroke patients. Fluctuations of A1AG1 and A1AT, both up-regulated in the ischemic brain, were detected in blood along the first week after onset. In summary, our results expand the knowledge of ischemic stroke pathology, revealing key molecules to be further explored as biomarkers and/or therapeutic targets

Influence of sex, age and diabetes on brain transcriptome and proteome modifications following cerebral ischemia

Diabetes; Proteome; SexDiabetis; Proteoma; SexeDiabetes; Proteoma; SexoIschemic stroke is a major cause of death and disability worldwide. Translation into the clinical setting of neuroprotective agents showing promising results in pre-clinical studies has systematically failed. One possible explanation is that the animal models used to test neuroprotectants do not properly represent the population affected by stroke, as most of the pre-clinical studies are performed in healthy young male mice. Therefore, we aimed to determine if the response to cerebral ischemia differed depending on age, sex and the presence of comorbidities. Thus, we explored proteomic and transcriptomic changes triggered during the hyperacute phase of cerebral ischemia (by transient intraluminal middle cerebral artery occlusion) in the brain of: (1) young male mice, (2) young female mice, (3) aged male mice and (4) diabetic young male mice. Moreover, we compared each group's proteomic and transcriptomic changes using an integrative enrichment pathways analysis to disclose key common and exclusive altered proteins, genes and pathways in the first stages of the disease. We found 61 differentially expressed genes (DEG) in male mice, 77 in females, 699 in diabetics and 24 in aged mice. Of these, only 14 were commonly dysregulated in all groups. The enrichment pathways analysis revealed that the inflammatory response was the biological process with more DEG in all groups, followed by hemopoiesis. Our findings indicate that the response to cerebral ischemia regarding proteomic and transcriptomic changes differs depending on sex, age and comorbidities, highlighting the importance of incorporating animals with different phenotypes in future stroke research studies.This work has been funded by Instituto de Salud Carlos III (PI18/00804) and by the European Regional Development Fund (FEDER). Neurovascular Research Laboratory takes part in the Spanish stroke research network RICORS-ICTUS. L.R is supported by a pre-doctoral fellowship from the Instituto de Salud Carlos III (IFI17/00012)

Association of A1AT With Poor Functional Outcome in Patients With Acute Ischemic Stroke

Biomarker; Outcome; strokeBiomarcador; Resultado; IctusBiomarcador; Resultat; IctusBackground This study aimed to investigate whether A1AT (α‐1 antitrypsin) bloodstream levels, measured acutely after ischemic stroke, can predict the outcome of patients with stroke. Methods and Results Two cohorts of patients with stroke were studied independently and retrospectively: a pilot cohort of 59 patients and a larger replicative study with 527 patients. Blood samples were drawn at hospital admission (2 a poor outcome). Association studies between A1AT levels and functional outcomes were conducted. We also evaluated the added value of A1AT as a prognostic biomarker over the clinical model (sex, age, premorbid modified Rankin Scale and National Institutes of Health Stroke Scale scores) with the likelihood ratio test. In both studies, the levels of A1AT were higher in patients who had worse outcomes, were older, and had higher National Institutes of Health Stroke Scale scores at admission. In the pilot study, higher levels of A1AT were also associated with death at discharge and at 3 months after stroke (P=0.035 and P=0.023, respectively). The addition of A1AT to the clinical model did not show enough evidence of increasing the fit of the model to the data in either cohort. Conclusions Based on our data, we cannot claim that A1AT is an independent biomarker of ischemic stroke. Nevertheless, A1AT is potentially involved in stroke outcomes and might be explored as a potential therapeutic target.The Neurovascular Research Laboratory takes part in the Redes de Investigación Cooperativa Orientadas a Resultados en Salud‐ICTUS Enfermedades Vasculares Cerebrales Network, Instituto de Salud Carlos III), Spain (RD21/0006/0007), and acknowledges funding for this project by a PI21/01158 grant from Fondos Semilla Dr Miguel Blanco of the Instituto de Salud Carlos III. A.B. received funding from Instituto de Salud Carlos III (INT22/00068), cofinanced by the Fondo Europeo de Desarrollo Regional

Charge effect of a liposomal delivery system encapsulating simvastatin to treat experimental ischemic stroke in rats

Although the beneficial effects of statins on stroke have been widely demonstrated both in experimental studies and in clinical trials, the aim of this study is to prepare and characterize a new liposomal delivery system that encapsulates simvastatin to improve its delivery into the brain. In order to select the optimal liposome lipid composition with the highest capacity to reach the brain, male Wistar rats were submitted to sham or transitory middle cerebral arterial occlusion (MCAOt) surgery and treated (intravenous [IV]) with fluorescent-labeled liposomes with different net surface charges. Ninety minutes after the administration of liposomes, the brain, blood, liver, lungs, spleen, and kidneys were evaluated ex vivo using the Xenogen IVIS ® Spectrum imaging system to detect the load of fluorescent liposomes. In a second substudy, simvastatin was assessed upon reaching the brain, comparing free and encapsulated simvastatin (IV) administration. For this purpose, simvastatin levels in brain homogenates from sham or MCAOt rats at 2 hours or 4 hours after receiving the treatment were detected through ultra-high-protein liquid chromatography. Whereas positively charged liposomes were not detected in brain or plasma 90 minutes after their administration, neutral and negatively charged liposomes were able to reach the brain and accumulate specifically in the infarcted area. Moreover, neutral liposomes exhibited higher bioavailability in plasma 4 hours after being administered. The detection of simvastatin by ultra-high-protein liquid chromatography confirmed its ability to cross the blood-brain barrier, when administered either as a free drug or encapsulated into liposomes. This study confirms that liposome charge is critical to promote its accumulation in the brain infarct after MCAOt. Furthermore, simvastatin can be delivered after being encapsulated. Thus, simvastatin encapsulation might be a promising strategy to ensure that the drug reaches the brain, while increasing its bioavailability and reducing possible side effects

Innate immune memory after brain injury drives inflammatory cardiac dysfunction

The medical burden of stroke extends beyond the brain injury itself and is largely determined by chronic comorbidities that develop secondarily. We hypothesized that these comorbidities might share a common immunological cause, yet chronic effects post-stroke on systemic immunity are underexplored. Here, we identify myeloid innate immune memory as a cause of remote organ dysfunction after stroke. Single-cell sequencing revealed persistent pro-inflammatory changes in monocytes/macrophages in multiple organs up to 3 months after brain injury, notably in the heart, leading to cardiac fibrosis and dysfunction in both mice and stroke patients. IL-1β was identified as a key driver of epigenetic changes in innate immune memory. These changes could be transplanted to naive mice, inducing cardiac dysfunction. By neutralizing post-stroke IL-1β or blocking pro-inflammatory monocyte trafficking with a CCR2/5 inhibitor, we prevented post-stroke cardiac dysfunction. Such immune-targeted therapies could potentially prevent various IL-1β-mediated comorbidities, offering a framework for secondary prevention immunotherapy.The authors thank Christina Fürle and Kerstin Thuß-Silczak for excellent technical support and Burkhardt Becher (University of Zurich) for providing Ccr2creERT2xAi14 mice. The study was supported by the Vascular Dementia Research Foundation, the European Research Council (ERC-StG 802305), the German Research Foundation (DFG) under Germany’s Excellence Strategy (EXC 2145 SyNergy ID 390857198 and EXC2151 ImmunoSensation ID 390873048), FOR 2879 (ID 405358801), CRC 1123 (ID 238187445), TRR 274 (ID 408885537), TRR 355 (ID 490846870), TRR 332 (INST 211/1066-1), a Walter-Benjamin Fellowship (SI 2832/1), the Corona Foundation (S199/10079/2019), the Munich School for Data Science (MUDS), the China Scholarship Council, and the UNION-CVD Clinician Scientist Programme (ID 413657723). The SICFAIL study was funded by the German Ministry of Research and Education (Comprehensive Heart Failure Centre Würzburg, BMBF #01EO1004 and #01EO1504).Peer reviewe