Stroke Alert April 2022

Stroke Alert

On Episode 15 of the Stroke Alert Podcast, host Dr. Negar Asdaghi highlights two articles from the April 2022 issue of Stroke: “Kawasaki Disease May Increase the Risk of Subsequent Cerebrovascular Disease” and “Effect of Moderate and Severe Persistent Hyperglycemia on Outcomes in Patients With Intracerebral Hemorrhage.” She also interviews Dr. François Gros-Louis about his article “Moyamoya Disease Susceptibility Gene RNF213 Regulates Endothelial Barrier Function.”

Dr. Negar Asdaghi:

1) How would you counsel the parent of a child who has just recovered from Kawasaki disease on their child's future risk of having a stroke?

2) Should we or should we not treat stress hyperglycemia in the setting of acute intracerebral hemorrhage?

3) What is the CRISPR-Cas9 gene editing technology? And why, if you haven't heard of it already, you most definitely should be listening to this podcast?

We're back here with the April issue of the Stroke Alert Podcast, and this is the latest in Stroke. Stay with us.

Dr. Negar Asdaghi: Welcome back to another extremely informative Stroke Alert Podcast. My name is Negar Asdaghi. I'm an Associate Professor of Neurology at the University of Miami Miller School of Medicine, and your host for the monthly Stroke Alert Podcast. The April 2022 issue of Stroke contains a range of really exciting papers and topics. In the paper titled "Vascular Response to Spreading Depolarization Predicts Stroke Outcome," we have a really interesting in vivo mouse model of ischemic stroke, looking at the spreading patterns of cortical depolarization and the subsequent vascular response to this by way of hyperemia. The researchers from Zurich University, led by Dr. Binder and colleagues, walk us through how the patterns of hyperemia can actually predict the severity of subsequent ischemic injury.

Dr. Negar Asdaghi: In a separate paper in this issue of the journal, we're reminded of how the classic NIH Stroke Scale can underestimate the severity of neurological symptoms and outcomes in patients with posterior circulation infarcts. In the paper led by Dr. Alemseged and colleagues, the investigators from the Royal Melbourne Hospital in Australia evaluate the prognostic accuracy of the Posterior NIH Stroke Scale, which is the modified version of the classic NIH Stroke Scale, in predicting the outcomes of patients with posterior circulation infarcts.

Dr. Negar Asdaghi: I encourage you to review these papers in addition to listening to our podcast today. Later in the podcast, I have the great pleasure of interviewing Dr. François Gros-Louis from Laval University in Quebec to discuss the latest in gene editing technology and how this technology has helped his team unravel the biological function of RNF213 susceptibility gene in Moyamoya disease. But first with these two articles.

Dr. Negar Asdaghi: Kawasaki disease, which was first described in 1976, is an acute febrile illness predominantly affecting children younger than five years of age. In addition to fever, other clinical signs of the disease include rash, bilateral conjunctival injection, cervical lymphadenopathy, swelling of the hands and feet, and irritation and inflammation of the mouth, lips, and throat. Now, for those of us like me who are adult neurologists, here is a quick review of the pathophysiology of Kawasaki disease.

Dr. Negar Asdaghi: This is a medium vessel vasculopathy, most significantly affecting the coronary arteries, a vasculopathy that is characterized by three linked pathological processes, necrotizing arteritis, subacute to chronic vasculitis, and luminal myofibroblastic proliferation. So, simply put, these processes can lead to stenotic lesions in various vascular beds, which are affected by this disease.

Dr. Negar Asdaghi: And as we mentioned earlier, the most recognized vascular blood vessels affected by Kawasaki disease are the coronary arteries, which can lead to myocardial ischemia, infarction, and sudden death in these cases. However, involvement of other vascular beds, including cerebral vessels, are also increasingly reported as part of Kawasaki disease.

Dr. Negar Asdaghi: So, in the current issue of the journal, Dr. Chien-Heng Lin from the Division of Pediatric Pulmonology at China Medical University Children's Hospital in Taiwan and colleagues studied the subsequent risk of cerebrovascular events in patients with Kawasaki disease. Using the National Health Insurance Research Database of Taiwan, they collected data on 8467 children with Kawasaki disease from 2000 to 2012. And for each child with Kawasaki, data was also collected on four randomly selected non-Kawasaki disease children who were matched with the Kawasaki cohort for sex, urbanization level of residence, and parental occupation.

Dr. Negar Asdaghi: So, that gave them a sample size of over 33,000 children for their non-Kawasaki cohort. And then they compared the risk of subsequent stroke in children between the two cohorts. The study period for any given patient would end when the said patient was either diagnosed with a cerebrovascular disease or withdrew from the research database.

Dr. Negar Asdaghi: So, in terms of their demographics, 61% of patients in the Kawasaki group were boys; 88% of the Kawasaki cohort were younger than five years of age. So, here are the findings. Number one, the incident rate of subsequent cerebrovascular disease was 14.7 per hundred thousand person years in the Kawasaki cohort versus only 4.6 per hundred thousand person years in the non-Kawasaki cohort. That's greater than a threefold higher incidence rate of cerebrovascular disorders for children who had Kawasaki disease before.

Dr. Negar Asdaghi: This finding was independent of other potential confounders, which they adjusted for in their multivariate analysis. Now, the length of follow up was a median of 9.8 years for the entire cohort. And on the issue of time, they found two important associations. The first finding was that when the follow-up time was stratified by five-year periods, Kawasaki disease cohort patients showed a significantly higher risk of developing a stroke within the first five years after being diagnosed.

Dr. Negar Asdaghi: And the second important association was that when they looked at the age at the time of diagnosis of Kawasaki, children who were younger than five years at the time of diagnosis were at a significantly higher risk of having a future stroke as compared to those who were older than five at the time of diagnosis.

Dr. Negar Asdaghi: So, simply put, the risk of subsequent stroke was higher in children who acquired the disease at a younger age, and that risk was higher in the first few years after the diagnosis of Kawasaki disease. The authors discuss a number of putative mechanisms to link Kawasaki with stroke. The most important being a cardiac source of embolism that we already alluded to, but other etiologies, including medium vessel cerebral vasculitis, or hypercoagulability in the setting of increased systemic inflammation, and even Kawasaki disease-associated aneurysmal rupture to cause hemorrhagic forms of stroke, are discussed in the paper and should be considered in the correct setting in children with a prior history of this disease.

Dr. Negar Asdaghi: So, what we learned from this large population-based pediatric study is that Kawasaki disease does indeed increase the risk of subsequent cerebrovascular disorders, and its influence is stronger in children who are diagnosed with this condition under the age of five, and the time period during which the risk of stroke is the highest is within the first five years after the diagnosis.

Dr. Negar Asdaghi: In the setting of spontaneous intracerebral hemorrhage, or ICH, much research has focused on the association between hypertension and blood pressure-lowering therapies and hematoma expansion and functional outcomes, but a lot less attention relatively has been given to the impact of hyperglycemia and ICH-related outcomes.

Dr. Negar Asdaghi: The current guidelines state that serum glucose should be monitored and both hypo- and hyperglycemia should be avoided in the setting of ICH. The older studies have given us inconsistent results as to whether or not hyperglycemia can increase the risk of ICH-related mortality. More recent studies have suggested that perhaps persistent hyperglycemia is indeed a predictor of poor neurological outcomes in ICH, but these results come from smaller single-center studies, which require further confirmation. And this confirmation is exactly what Dr. Adnan Qureshi from Zeenat Qureshi Stroke Institute and the Department of Neurology at University of Missouri and colleagues aim to give us in their study titled "Effect of Moderate and Severe Persistent Hyperglycemia on Outcomes in Patients With Intracerebral Hemorrhage."

Dr. Negar Asdaghi: So, they use data from the ATACH-2 study, and a quick reminder that ATACH-2 was a multicenter randomized control trial of a thousand patients with acute spontaneous intracerebral hemorrhage enrolled within four and a half hours from symptom onset, and patients were randomized to either the intensive blood pressure control treatment arm to maintain their systolic blood pressure goal of 110 to 139 millimeter of mercury versus standard treatment arm, which was keeping their systolic blood pressure above 140, between 140 to 179 millimeter of mercury, in the first 24 hours after randomization.

Dr. Negar Asdaghi: You will recall that enrollment of ATACH-2 was stopped early because of futility after pre-specified interim analysis. The main results of the trial was published in 2016 in New England Journal of Medicine, and the primary results did not show a lower rate of death or disability in patients assigned to the intensive treatment group.

Dr. Negar Asdaghi: So, in the current paper, in this current issue of the journal, the authors looked at the glycemic status of the patients enrolled in the trial. As part of the trial, patients had a complete chemistry panel at baseline, 24, 48, and 72 hours from onset. So, they used the glucose measurement from this panel and defined moderate hyperglycemia as serum glucose level of over 140 and under 180 and severe hyperglycemia as serum glucose levels of equal or greater than 180.

Dr. Negar Asdaghi: Now, persistent hyperglycemia was if two consecutive serum glucose levels were in the moderate or severe categories. And, very simply, they looked at the effects of hyperglycemia on ICH outcomes. And importantly, they evaluated whether hyperglycemia modified the effects of intensive blood pressure reduction on outcomes of ICH. So, of the thousand participants in ATACH-2, 11% had persistent moderate hyperglycemia, and 17% had severe persistent hyperglycemia. Those in the hyperglycemic group were more likely to be diabetic, not surprisingly, more likely to have a history of hypertension and dyslipidemia as compared to the normal glycemic patients.

Dr. Negar Asdaghi: And here are the results. Number one, serious adverse events were higher in the hyperglycemic groups, whether we're talking about the moderate or the severe hyperglycemic groups. This is despite the fact that the rate of hematoma expansion and perihematomal edema was not different based on the hyperglycemic status. However, the hyperglycemic patients were more likely to have serious adverse events, which were operationally defined as complications that were not expected to have occurred from the study intervention, in this case, the intensive hypertensive therapy, and resulted in either death or prolonged hospitalization or persistent or significant disabilities. Now, serious renal adverse events, which are, of course, expected as a complication for aggressive blood pressure therapy, were also significantly higher in the hyperglycemic category.

Dr. Negar Asdaghi: Now, their next important finding was that overall, both moderate and severe hyperglycemia was associated with higher odds of 90 days disability or death post-ICH adjusting for typical variables that could predict these outcomes, such as GCS score, hematoma volume, presence or absence of intraventricular hemorrhage, amongst other factors that they accounted for.

Dr. Negar Asdaghi: Now, number three, this is perhaps the most important finding of the study. Among patients without a preexisting history of diabetes, both moderate and severe hyperglycemia increased the risk of death and disability at 90 days after adjusting for all the potential confounders, but hyperglycemia was not associated with these poor outcomes in those with a prior history of diabetes. I'm going to pause here to let this information sink in. Let's go over them again, stress hyperglycemia in non-diabetics was associated with poor ICH outcomes, but high sugars in diabetics did not predict the same poor outcomes. And finally, they looked at the possible interactions between the glycemic status and the ATACH-2 intervention, which as we alluded to earlier, which was intensive versus standard blood pressure therapy, and it turns out that the intensive systolic blood pressure reduction was indeed associated with a lower rate of hematoma expansion only in patients with normal glycemia, but not in those with moderate or severe hyperglycemia.

Dr. Negar Asdaghi: So, this is again food for thought. Simply put, if the sugars are not well controlled, it appears that intensive blood pressure control would not lower the rate of hematoma expansion. Blood pressure lowering works when the sugar levels are controlled. So, overall, here are the two simple messages of this study. Number one, hyperglycemia in the acute setting of intracerebral hemorrhage is associated with poor outcomes or death only in those with stress hyperglycemia, meaning in those who have high sugar levels, but are not diabetic.

Dr. Negar Asdaghi: Number two, there seems to be an important interaction between the acute glycemic status of the patients and how intensive blood pressure control can prevent hematoma expansion, in that intensive BP control is only effective in prevention of hematoma expansion if the sugar levels are normal. So, a lot of thought-provoking and hypothesis-generating findings, and definitely more to come on this topic.

Dr. Negar Asdaghi: Moyamoya disease, or MMD, is an idiopathic disorder characterized by progressive stenosis of the supraclinoid internal carotid artery and its main branches in subsequent formation of a network of abnormal lenticulostriate collaterals. First described in Japan, the term "Moyamoya" is a Japanese expression for the puff of smoke and describes the characteristic appearance of the tangled and abnormal collateral vessels that are seen in angiography in various stages of the Moyamoya disease.

Dr. Negar Asdaghi: Epidemiological studies have revealed several risk factors associated with Moyamoya disease, including Asian ethnicity, female gender, and a family history of the disorder. Given that 15% of MMD patients have a family history of this disease, it's not surprising that genetic factors are suspected to underlie its pathogenesis. Now, a polymorphism in the ring finger protein 213, or RNF213, gene on chromosome 17 has been identified as the strongest genetic susceptibility factor for Moyamoya disease specifically in the East Asian population.

Dr. Negar Asdaghi: But despite the many advances in understanding the pathophysiology of MMD, as well as advances in animal models and genetic studies, to date, none of the animal models of RNF213 have quite replicated the vascular abnormalities that are typically seen in human Moyamoya disease.

Dr. Negar Asdaghi: The scientists feel that this is related to how little is known about the exact biological function of RNF213 gene and the protein it encodes. So, in the current issue of the journal, in the study titled "Moyamoya Disease Susceptibility Gene RNF213 Regulates Endothelial Barrier Function," Dr. François Gros-Louis from CHU de Québec Research Center at Laval University in Québec and colleagues aim to study the biological functions of RNF213 using a novel genome editing technology by the name of CRISPR-Cas9 technology.

Dr. Negar Asdaghi: Joining me now is Dr. Gros-Louis himself to discuss the findings of this paper. Dr. Gros-Louis is a Professor of Neurosciences at the Department of Surgery at Laval University. He holds the Canada Research Chair in Brain Disease Modeling and is the Director of the Induced Pluripotent Stem Cell Platform research in Québec.

Dr. Negar Asdaghi: Good morning, François. Welcome to our podcast. And thank you so much for joining us.

Dr. François Gros-Louis: My pleasure.

Dr. Negar Asdaghi: François, you have to promise to hold my clinician's hand through this interview as obviously these are some foreign subjects for us, but very excited to learn from your study and learn from you on the association between RNF213 and the pathophysiology of what happens in Moyamoya disease. Now, before we talk about your paper, can you please talk to us about some basic concepts? What is the RNF213 protein?

Dr. François Gros-Louis: Yes. The RNF213 gene is thought to be involved in mediating protein, protein interactions. The protein also contains a domain which is associated with an ATPase activity. This gene is a susceptibility gene for Moyamoya disease, as you mentioned in the introduction, vascular disorder of intracranial arteries. It's encoded in ubiquitously expressed protein. The protein is found to be expressed throughout the cytocell with the partial association in the intracellular membrane and cytoskeleton. Its expression varies according to the tested tissue type or location or cellular types.

Dr. François Gros-Louis: Although the function of RNF213 protein is unknown, studies suggest that it plays a role in the proper development of blood vessels, cell proliferation, and inflammation. Recently, RNF213 has been reported to be associated with angiogenesis. However, little is known about its endogenous function or its pathogenic role in Moyamoya disease. Our results are in line with these results and indicate that RNF213 could also be a key regulator of cerebral endothelial integrity, whose disruption could be an early pathological mechanism leading to Moyamoya disease.

Dr. Negar Asdaghi: So, just to continue on this, there's quite a bit of research already done on association of the RNF213 gene, that's located, as we noted earlier, on chromosome 17, and basically susceptibility of development of Moyamoya disease. Can you give our listeners a brief overview of this genetic connections and what was known from past research?

Dr. François Gros-Louis: Yeah, there is a couple polymorphism describing this gene, the most frequent, the most prevalent genetic study have identified the variant R4810K, meaning for arginine is replaced by another amino acid at the position of 4810 within the protein. It's a large protein and a large gene and a susceptible gene and a risk factor for developing Moyamoya disease.

Dr. François Gros-Louis: So, people bearing this variant have a higher chance to develop the disease. This is a loss of function variant, also called inactivating mutation, meaning that the mutated gene product have less or no function. So, this variant is found in heterozygous, meaning one copy, or two copy homozygous in Moyamoya disease patients. While patient bearing homozygous mutation develop a more severe disease with earlier age of onset and worse prognosis, patients bearing heterozygous mutation can also develop the disease.

Dr. François Gros-Louis: So, strong evidence suggests that the carrying rate of RNF213 R4810K mutant is closely related and give a higher chance to develop the disease. Interestingly, also with colleagues, we found that there are other variants within this genes leading to what we think is a gain of function mutation have been associated also with other cerebrovascular disease, such as intracranial aneurysms.

Dr. Negar Asdaghi: So, François, this is very interesting. Let me recap what you mentioned so I know that I understood it. So, this is an interesting gene, this RNF213, and basically evidence shows that mutations in the RNF213, whether it's loss of function or gain of function, both can result in variety of cerebrovascular disorders. And interestingly, the phenotype of the disease when it comes to loss of function of this gene is actually correlated with whether a person is a carrier, homozygous carrier of this gene, loss of function, or heterozygous carrier of the gene.

Dr. Negar Asdaghi: So, very interesting information for clinicians who treat patients with Moyamoya disease, specifically those who have a family history of Moyamoya disease, so perhaps a higher chance of carrying a genetic susceptibility gene. Now, we want to get to the paper that you published in this issue of the journal, but I think before we talk about your paper, we also have to have a basic understanding of this CRISPR-Cas9 technology, which is the new genome editing technology that you use in your experiments. Can you please give us a little bit of an overview of this technology?

Dr. François Gros-Louis: Yes. CRISPR-Cas9 gene editing is genetic engineering technique in molecular biology by which the genomes of living organisms may be modified. This technology allows genetic material to be added, removed, or altered at particular location in the genome. Several approaches to genome editing have been developed. Recent one is known as CRISPR-Cas9. So, the CRISPR-Cas9 system has generated a lot of excitement in the scientific community because it is faster, cheaper, and more accurate, and also more efficient than other existing genome editing methods. It's clearly revolutionizing the field in research.

Dr. Negar Asdaghi: So, it's very exciting. It's truly a new chapter in gene targeting research and editing research. So, now we're ready to hear about your study. And I guess the first part of the study was just to look at how various cells in vitro that you used had expressed RNF213. Can you please tell us about the first part of your experiments?

Dr. François Gros-Louis: Yeah. We first wanted to know where the protein is expressed or where the protein is more highly expressed. So, we found by doing immunofluorescence analysis that the RNF213, so we confirmed that it's ubiquitously expressed in the cytoplasm of different cellular types. So, we found that significant difference also in the expression of RNF213 protein levels in several endothelial cells, where we found it's been highly expressed when compared to other endothelial cells isolated from different other body location, meaning outside of the CNS. So, it's highly expressed also when compared to smooth muscle cells or fibroblasts.

Dr. Negar Asdaghi: Okay. So, just again, to recap for our listeners, this is, this RNF213 protein, is ubiquitously expressed in many different cell types, but you did find a significantly higher expression rates in endothelial cells, specifically those endothelial cells that were derived from cerebrovasculature. So, that's the first exciting part of the experiments that you showed in the study. Now, using the CRISPR-Cas9 technology, you and your team were able to successfully create an in vitro RNF213 knockout model. Can you please tell us about these models and also the main findings of your study?

Dr. François Gros-Louis: Yeah, so taken together, the results we presented in the article indicate that RNF213 could be a key regulator of cerebral, endothelial and tight junctions integrity whose disruption could be an early pathological mechanisms leading to Moyamoya disease. So, we established for the first time an easily reproducible and stable in vitro 3D model generated using the CRISPR-Cas9 gene editing technology.

Dr. François Gros-Louis: This advanced 3D culture approach has emerged as an excellent system to recapitulate histopathological feature reminiscent to disease pathogenesis. So, 3D cell culture approach is different from standard 2D culture, where cells are cultured, monolayered into a Petri dish. And we have results showing that the 3D cell culture system better mimic the in vivo conditions in terms of cell to cell and cell to matrix interaction and lead to histopathological phenotypic feature can be observed in cell culture, in a 3D fashion. Quite interestingly, alongside of providing the first evidence for the role of RNF213, the maintenance of endothelial barrier and the potential implication of this gene in the expression of maturation of tight junctions. So, we define a novel role for PECAM-1 as well in barrier impairment as a part of the disease pathogenic mechanisms.

Dr. Negar Asdaghi: Okay. And now this is really interesting. So, I wanted to, again, recap some of the important points that you raised here. First of all, your in vitro models are different than the classic in vitro models, where 2D cells were basically grown in a Petri dish. You are trying to, more and more, replicating what happens, for instance, in blood vessels, where you have endothelial cells overlying mesenchymal cells underneath them, so tunica intima and then tunica media, and so you have 3D cells, where various types of cells are overlying each other in a more in vivo representation of what happens in blood vessels, which is truly interesting.

Dr. Negar Asdaghi: And what you found was, in sort of summary, was that these knockout endothelial cells ended up having abnormal tight junctions and abnormal connectivity, which basically would lead in an in vivo model to abnormal leaky blood brain barrier, if this were truly in the in vivo model. Does that summarize the findings of the paper?

Dr. François Gros-Louis: Yes, perfectly.

Dr. Negar Asdaghi: Perfect. And so I want to also give us a chance to talk about the important pro-inflammatory aspects of these knockout cells. You did find that a number of cytokines were expressed in excess in those RNF213 deficient cells. Can you please elaborate on those findings?

Dr. François Gros-Louis: So, to further investigate whether inflammation plays an important role in RNF213-associated Moyamoya disease development, we indeed performed experiments to study pro-inflammatory cytokines and analyze the immune secretome profiles of cerebral RNF213 deficient endothelial cells. So, then the cells can secrete different cytokines or different other proteins. So, by analyzing the secretome, we found an end secretion of a few pro-inflammatory cytokines indicating that inflammation may also play a central role in the initiation of the immune response in the pathogenesis of the disease.

Dr. Negar Asdaghi: So, this is exciting, François. For years, we thought about the pathophysiology of Moyamoya disease as a disorder involving large vessels. And perhaps the initial thought was that it starts with excessive proliferation of smooth muscles within the middle layer of the cerebral blood vessels, in tunica media, and then perhaps subsequently there will be other abnormalities, including the intimal hyperplasia that is classically seen in Moyamoya.

Dr. Negar Asdaghi: Your study seems to propose a shift in that pathophysiological paradigm, where the problem seems to start from endothelial cells, so inside of the blood vessels and the tunica intima, and then gradually would go out to the middle layers, and, of course, proposes the hyperinflammatory state in the Moyamoya disease as well. So truly interesting. Do you think that that is the new or rather a paradigm shift for pathophysiology of MMD?

Dr. François Gros-Louis: That's a great question. Our results certainly demonstrated that endothelial cells are involving in the disease pathogenesis in Moyamoya disease, but it doesn't exclude the possibility that other cell types might also be involved in the disease pathogenesis. We know, like you mentioned, that a blood vessel is formed by two different cell layers, tunica intima, media, and adventitia, containing, respectively, endothelial cells, smooth muscle cells, and fibroblasts. So which cells are to be blamed in Moyamoya disease is a question of many ongoing results studies over the years.

Dr. François Gros-Louis: So, using tissue-engineered approach to reconstruct small caliber blood vessels, as we developed in my lab, in combination with patient-derived stem cells, in which adult cells isolated from a patient of any individuals can be reprogrammed into stem cells and re-differentiated into different cell types in occurrence, smooth muscle, fibroblasts, or endothelial cells. We would like to generate blood vessels in which each of the different cellular layers will harbor or not, or a combination with RNF213 mutants. So, this will hopefully help us to elucidate this question.

Dr. Negar Asdaghi: That's perfect. So, François, before we end the interview, I wanted to ask two more questions. So, what should be our top two takeaway messages from your study?

Dr. François Gros-Louis: We believe that the innovative transdisciplinary approach to generate, for the first time, as we describe in the article, an in vitro 3D model recapitulating important diseases features. So, this model could become a unique tool in precision medicine to study Moyamoya disease or other RNF213-associated pathologies. So, our study provides, for the first time, role of RNF213 in the maintenance of blood-brain barrier and the potential implication of RNF213 in the expression and maturation of tight junctions. Taken together, our data define a novel role for PECAM-1 in the blood-brain barrier impairment in Moyamoya disease.

Dr. François Gros-Louis: So, better characterization of each, also this regulated inflammatory molecules, we found taken separately could reveal a crucial information and help elaborate a more precise approach. Hence, this pro-inflammatory signature could be used as a circulatory biomarker for the follow-up of Moyamoya disease patients and to manage an appropriate treatment, according to the pathology progression.

Dr. Negar Asdaghi: François, this is great. And last, I want to digress a little bit and ask you about the future of gene editing. I think it's important to end our interview with a little bit of a discussion regarding the future of CRISPR-Cas9 technology. In subatomic quantum physics, people talk about the God particles. And I feel that the CRISPR-Cas9 technology is, in a way, like playing God, if you agree. What do you think is the future for gene editing, and how do you see that helping us in terms of treatment of genetic causes of cerebrovascular disorders?

Dr. François Gros-Louis: Yes, gene editing is, like I said, revolutionizing, of course, experimental therapies for genetic disorder and generated excitement for new and improved gene therapies. We can think that it will be possible to correct any gene mutations associated with a disease to reestablish the normal or natural gene function and help treating the targeted diseases. But also, to me, the future of genome editing also resides in optimizing next generation disease models. The use of genome editing, in particular, the CRISPR-Cas9 technology, has extended to potential in generating new personalized model for a number of disorder, not only including Moyamoya disease or other cerebrovascular diseases, but also diseases like Alzheimer's, ALS, or Parkinson's disease, for which obtaining patient sample is difficult.

Dr. François Gros-Louis: No one wants to give up a bit of his brain. So modeling it, this disease, in vitro will be really helpful in combination also gene editing with the stem cells, induced pluripotent stem cells technology, will allow the generation of better model to mimic human disease and reflects the genetic drivers that govern specific pathology. So, the synergy between IPS cell-based model system and gene editing will play a pivotal role in the root of precision medicine and clinical translation in the future.

Dr. Negar Asdaghi: Dr. François Gros-Louis, it was a pleasure learning from you. And we look forward to the endless possibilities brought by the future of genome editing technology.

Dr. François Gros-Louis: It was a pleasure discussing with you.

Dr. Negar Asdaghi: Thank you for joining us.

Dr. Negar Asdaghi: And this concludes our podcast for the April 2022 issue of Stroke. Please be sure to check out this month's table of contents for the full list of publications, including a series of Focused Updates on the topic of blood pressure management in stroke, organized by Dr. Else Sandset. I would also like to draw your attention to two scientific statements from the American Heart Association, which appear in print in the April issue. The first one is titled "Identifying Best Practices to Improve Evaluation and Management of In-Hospital Stroke," and the second one is on the effect of marijuana use on brain health.

Dr. Negar Asdaghi: And now, to end our podcast, last month, in honor of the 2022 Olympic Games, and to celebrate those with determination to survive and push despite the most difficult of circumstances, we ended our podcast with the story of a refugee Olympic athlete.

Dr. Negar Asdaghi: Sadly, since our last podcast, the world has seen even darker days of war, mass immigration, displacement, and human suffering. At times like this, we're reminded that although not all of us can help everyone, but at least each of us can do something to help someone, and the comfort in knowing that what we do in the field of medicine, from daily patient care to the scientific work leading to the next medical breakthrough, every action is a step forward in reducing the suffering of another person. And what better way to do this than staying alert with Stroke Alert.

Dr. Negar Asdaghi: This program is copyright of the American Heart Association, 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, visit AHAjournals.org.