Preventing dementia by preventing stroke: The Berlin Manifesto.

The incidence of stroke and dementia are diverging across the world, rising for those in low- and middle-income countries and falling in those in high-income countries. This suggests that whatever factors cause these trends are potentially modifiable. At the population level, neurological disorders as a group account for the largest proportion of disability-adjusted life years globally (10%). Among neurological disorders, stroke (42%) and dementia (10%) dominate. Stroke and dementia confer risks for each other and share some of the same, largely modifiable, risk and protective factors. In principle, 90% of strokes and 35% of dementias have been estimated to be preventable. Because a stroke doubles the chance of developing dementia and stroke is more common than dementia, more than a third of dementias could be prevented by preventing stroke. Developments at the pathological, pathophysiological, and clinical level also point to new directions. Growing understanding of brain pathophysiology has unveiled the reciprocal interaction of cerebrovascular disease and neurodegeneration identifying new therapeutic targets to include protection of the endothelium, the blood-brain barrier, and other components of the neurovascular unit. In addition, targeting amyloid angiopathy aspects of inflammation and genetic manipulation hold new testable promise. In the meantime, accumulating evidence suggests that whole populations experiencing improved education, and lower vascular risk factor profiles (e.g., reduced prevalence of smoking) and vascular disease, including stroke, have better cognitive function and lower dementia rates. At the individual levels, trials have demonstrated that anticoagulation of atrial fibrillation can reduce the risk of dementia by 48% and that systolic blood pressure lower than 140 mmHg may be better for the brain. Based on these considerations, the World Stroke Organization has issued a proclamation, endorsed by all the major international organizations focused on global brain and cardiovascular health, calling for the joint prevention of stroke and dementia. This article summarizes the evidence for translation into action.

Preimplantation-stage stem cells induce long-term allogeneic graft acceptance without supplementary host conditioning.

Hematopoietic stem cells have been successfully employed for tolerance induction in a variety of rodent and large animal studies. However, clinical transplantation of fully allogeneic bone marrow or blood-borne stem cells is still associated with major obstacles, such as graft-versus-host disease or cytoreductive conditioning-related toxicity. Here we show that when rat embryonic stem cell-like cells of WKY origin are injected intraportally into fully MHC-mismatched DA rats, they engraft permanently (>150 days) without supplementary host conditioning. This deviation of a potentially alloreactive immune response sets the basis for long-term graft acceptance of second-set transplanted WKY cardiac allografts. Graft survival was strictly correlated with a state of mixed chimerism, which required functional thymic host competence. Our results provide a rationale for using preimplantation-stage stem cells as vehicles in gene therapy and for the induction of long-term graft acceptance.

[Renin-Angiotensin-System (RAS) and COVID-19 - On The Prescription of RAS Blockers]. / Renin-Angiotensin-System (RAS) und COVID-19 ­ Zur Verordnung von RAS-Blockern.

Twenty years ago, an enzyme homologous to the previously known angiotensin-converting enzyme (ACE) was identified, and subsequently named ACE2. In the renin-angiotensin system (RAS), ACE2 has counter-regulatory functions against the classical effector peptide angiotensin II, for example in blood pressure regulation and cardiovascular remodeling. However, ACE2 provides an initially unexpected interesting link between virology and cardiovascular medicine. That is, ACE2 represents the binding receptor for the cellular uptake of SARS-CoV and SARS-CoV-2 viruses. Thus, ACE2 is relevant for COVID-19. In this context, it was suspected that therapy with RAS blockers might promote transmission and complications of COVID-19 by upregulation of ACE2 expression. The aim of this short review is, to describe the link between the RAS, particularly ACE2, and COVID-19. Based on our analysis and evaluation of the available findings, we justify our conclusion: important drugs such as ACE inhibitors and angiotensin receptor blockers should continue to be prescribed according to guidelines to stable patients in the context of the COVID-19 pandemic.

Chronic immunoneutralization of brain angiotensin-(1-12) lowers blood pressure in transgenic (mRen2)27 hypertensive rats.

Angiotensin-(1-12) [ANG-(1-12)] is a newly identified peptide detected in a variety of rat tissues, including the brain. To determine whether brain ANG-(1-12) participates in blood pressure regulation, we treated male adult (mRen2)27 hypertensive rats (24-28 wk of age) with Anti-ANG-(1-12) IgG or Preimmune IgG via an intracerebroventricular cannula for 14 days. Immunoneutralization of brain ANG-(1-12) lowered systolic blood pressure (-43 +/- 8 mmHg on day 3 and -26 +/- 7 mmHg on day 10 from baseline, P < 0.05). Water intake was lower on intracereroventricular day 6 in the Anti-ANG-(1-12) IgG group, accompanied by higher plasma osmolality on day 13, but there were no differences in urine volume, food intake, or body weight during the 2-wk treatment. In Preimmune IgG-treated animals, there were no significant changes in these variables over the 2-wk period. The antihypertensive effects produced by endogenous neutralization of brain ANG-(1-12) suggest that ANG-(1-12) is functionally active in brain pathways regulating blood pressure.

Update on tissue renin-angiotensin systems.

Angiotensin (Ang) II is not only generated in the circulation by renin and angiotensin-converting enzyme (ACE) but also is produced locally in numerous organs including kidney, vessels, heart, adrenal gland, eye, testis, and brain. Furthermore, widely distributed mast cells have been shown to be a production site. Local Ang II production process is commonly termed the result of a "tissue" renin-angiotensin system (RAS). Because pharmacological experiments do not easily allow targeting of specific tissues, many novel findings about the functional importance of tissue RAS have been collected from transgenic rodent models. These animals either overexpress or lack RAS components in specific tissues and thereby elucidate their local functions. The data to date show that in most tissues local RAS amplify the actions of circulating Ang II with important implications for physiology and pathophysiology of cardiovascular diseases. This review summarizes the recent findings on the importance of tissue RAS in the most relevant cardiovascular organs.

Special topic section: linkages among cerebrovascular, cardiovascular, and cognitive disorders: Preventing dementia by preventing stroke: The Berlin Manifesto.

The incidence of stroke and dementia are diverging across the world, rising for those in low-and middle-income countries and falling in those in high-income countries. This suggests that whatever factors cause these trends are potentially modifiable. At the population level, neurological disorders as a group account for the largest proportion of disability-adjusted life years globally (10%). Among neurological disorders, stroke (42%) and dementia (10%) dominate. Stroke and dementia confer risks for each other and share some of the same, largely modifiable, risk and protective factors. In principle, 90% of strokes and 35% of dementias have been estimated to be preventable. Because a stroke doubles the chance of developing dementia and stroke is more common than dementia, more than a third of dementias could be prevented by preventing stroke. Developments at the pathological, pathophysiological, and clinical level also point to new directions. Growing understanding of brain pathophysiology has unveiled the reciprocal interaction of cerebrovascular disease and neurodegeneration identifying new therapeutic targets to include protection of the endothelium, the blood-brain barrier, and other components of the neurovascular unit. In addition, targeting amyloid angiopathy aspects of inflammation and genetic manipulation hold new testable promise. In the meantime, accumulating evidence suggests that whole populations experiencing improved education, and lower vascular risk factor profiles (e.g., reduced prevalence of smoking) and vascular disease, including stroke, have better cognitive function and lower dementia rates. At the individual levels, trials have demonstrated that anticoagulation of atrial fibrillation can reduce the risk of dementia by 48% and that systolic blood pressure lower than 140 mmHg may be better for the brain. Based on these considerations, the World Stroke Organization has issued a proclamation, endorsed by all the major international organizations focused on global brain and cardiovascular health, calling for the joint prevention of stroke and dementia. This article summarizes the evidence for translation into action. © 2019 the Alzheimer's Association and the World Stroke Organisation. Published by Elsevier Inc. All rights reserved.

Angiotensin-(1-7) and baroreflex function in nucleus tractus solitarii of (mRen2)27 transgenic rats.

BACKGROUND: Endogenous angiotensin (Ang)-(1-7) enhances, while Ang II attenuates, baroreceptor sensitivity (BRS) for reflex control of heart rate (HR) in Sprague-Dawley (SD) rats. In (mRen2)27 renin transgenic rats [(mRen2)], there is overexpression of the mouse Ren2 gene in brain, leading to elevated Ang II and reduced Ang-(1-7) in brain medullary, and associated with hypertension and impaired BRS. METHODS: We therefore tested the contribution of endogenous Ang-(1-7) to BRS for control of HR and responses to cardiac vagal chemosensitive afferent fiber activation (CVA) with phenylbiguanide (PBG) in anesthetized SD and (mRen2) 27 rats before and after bilateral nucleus of the solitary tract (nTS) injection of the Ang-(1-7) receptor antagonist (D-Ala7)-Ang-(1-7). RESULTS: (mRen2) 27 rats exhibited a approximately 50% impairment in BRS as compared with SD (P < 0.05). (D-Ala7)-Ang-(1-7) attenuated BRS by approximately 50% in SD rats, but was without effect in (mRen2) 27 rats. (D-Ala7)-Ang-(1-7) did not alter the responses to CVA by PBG (iv bolus) in either strain. There were no differences in the depressor effects of Ang-(1-7) injected into the nTS, nor were levels of mRNA different for angiotensin-converting enzyme, angiotensin-converting enzyme 2, neprilysin, or the mas receptor in medullary tissue from SD versus (mRen2)27 rats. CONCLUSION: Endogenous Ang-(1-7) does not provide tonic input in the nTS to modulate BRS for control of HR in (mRen2)27 rats, which may contribute to impairment of BRS in these animals.

Implementing the proclamation of stroke and potentially preventable dementias.

Brain health plays a central role in well-being and in the management of chronic diseases. Stroke and dementia pose the two greatest threats to brain health, but recent developments suggest the possibility that preventing stroke may also prevent some dementias: (a) A large population study showed a 32% decrease in the incidence of stroke and a concomitant 7% reduction in the incidence of dementia; (b) the treatment of atrial fibrillation resulted not only in stroke reduction, but also a 48% decrease in dementia; (c) the hypothesis-free analyses have shown that the first phase of Alzheimer disease involves vascular dysregulation, opening the door to new therapeutic approaches; (d) cognitive impairment, often treatable and reversible, accompanies heart and kidney failure. These developments, combined with the knowledge that stroke, dementia, and heart disease share the same major treatable risk factors, particularly hypertension, offer an opportunity for their joint prevention. This aspiration is expressed by a Proclamation of the World Stroke Organization on Stroke and Potentially Preventable Dementias and endorsed by the World Heart Federation, the World Hypertension League, Alzheimer Disease International, and 18 other international, regional, and national organizations as a call for action.

Implementing the Proclamation of Stroke and Potentially Preventable Dementias.

Brain health plays a central role in wellbeing and in the management of chronic diseases. Stroke and dementia pose the two greatest threats to brain health, but recent developments suggest the possibility that preventing stroke may also prevent some dementias: 1. A large population study showed a 32% decrease in the incidence of stroke and a concomitant 7% reduction in the incidence of dementia; 2. Treatment of atrial fibrillation resulted not only in stroke reduction, but a 48% decrease in dementia; 3. A hypothesis free analyses has shown that the first phase of Alzheimer disease involves vascular dysregulation, opening the door to new therapeutic approaches; 4. Cognitive impairment, often treatable and reversible, accompanies heart and kidney failure. These developments, combined with the knowledge that stroke, dementia and heart disease share the same major treatable risk factors, particularly hypertension, offers an opportunity for their joint prevention. This aspiration is expressed by a Proclamation of the World Stroke Organization on Stroke and Potentially Preventable Dementias and endorsed by the World Heart Federation, the World Hypertension League, Alzheimer Disease International and 18 other international, regional and national organizations as a call for action.

Identification of hypertension-related genes through an integrated genomic-transcriptomic approach.

In search for the genetic basis of hypertension, we applied an integrated genomic-transcriptomic approach to identify genes involved in the pathogenesis of hypertension in the Sabra rat model of salt-susceptibility. In the genomic arm of the project, we previously detected in male rats two salt-susceptibility QTLs on chromosome 1, SS1a (D1Mgh2-D1Mit11; span 43.1 cM) and SS1b (D1Mit11-D1Mit4; span 18 cM). In the transcriptomic arm, we studied differential gene expression in kidneys of SBH/y and SBN/y rats that had been fed regular diet or salt-loaded. We used the Affymetrix Rat Genome RAE230 GeneChip and probed >30,000 transcripts. The research algorithm called for an initial genome-wide screen for differentially expressed transcripts between the study groups. This step was followed by cluster analysis based on 2x2 ANOVA to identify transcripts that were of relevance specifically to salt-sensitivity and hypertension and to salt-resistance. The two arms of the project were integrated by identifying those differentially expressed transcripts that showed an allele-specific hypertensive effect on salt-loading and that mapped within the defined boundaries of the salt-susceptibility QTLs on chromosome 1. The differentially expressed transcripts were confirmed by RT-PCR. Of the 2933 genes annotated to rat chromosome 1, 1102 genes were identified within the boundaries of the two blood pressure QTLs. The microarray identified 2470 transcripts that were differentially expressed between the study groups. Cluster analysis identified genome-wide 192 genes that were relevant to salt-susceptibility and/or hypertension, 19 of which mapped to chromosome 1. Eight of these genes mapped within the boundaries of QTLs SS1a and SS1b. RT-PCR confirmed 7 genes, leaving TcTex1, Myadm, Lisch7, Axl-like, Fah, PRC1-like, and Serpinh1. None of these genes has been implicated in hypertension before. These genes become henceforth targets for our continuing search for the genetic basis of hypertension.

Building Bridges through Science.

Science is ideally suited to connect people from different cultures and thereby foster mutual understanding. To promote international life science collaboration, we have launched "The Science Bridge" initiative. Our current project focuses on partnership between Western and Middle Eastern neuroscience communities.