Small Vessel Cerebrovascular Disease

Diet is established among the most relevant adjustable variables of human health in modern societies. The recognition by the World Health Organization of cognitive impairment and dementia associated with aging as one of the major public health challenges of our time, highlights the imperative need for a more comprehensive understanding of how different aspects of lifestyle, in particular diet, affect neural function and consequent cognitive performance throughout lifespan. The brain is endowed with fine mechanisms for a precise spatial and temporal control of cerebral blood flow (CBF) according to neural activity, the neurovascular coupling (NVC). Mounting evidence from preclinical and human studies demonstrate that NVC dysfunction is a key early factor contributing to the pathogenesis of cognitive decline and vascular cognitive impairment (VCI) in aging and conditions associated with accelerated microvascular aging, such as cerebral small vessel disease (cSVD). Failure at any part of the NVC pathway disrupts CBF resulting in catastrophic depletion of oxygenation and energy supply to brain cells, and, in the long run, to neuronal dysfunction and cognitive impairment. The investigators have shown that nitric oxide (NO) synthesized by neuronal nitric oxide synthase (nNOS) is a direct mediator of NVC and that decreased bioavailability of NO along aging compromised NVC and reduced local CBF. Shortly after the identification of nNOS as a source of NO for vasodilation in the brain, an alternative pathway for NO production independent of nNOS, relying on the sequential reduction of nitrate, the nitrate:nitrite:NO pathway, was unveiled. Nitrate consumed in green leafy vegetables as part of a normal diet is bioactivated to nitrite and both compounds are permanent constituents of blood/tissues in animal species, influencing CBF and resulting in improvements in learning and memory in rodents and VCI patients. However, a critical question remains on whether NO produced from nitrite is functionally linked to neuronal activation. This is key to understanding whether dietary nitrate can be linked to neuronal-dependent CBF increases and cognitive performance. The investigators and others have shown that upon excitatory stimulation, ascorbate is released from neurons being available for nitrite reduction and our preliminary data supports that NO bioavailability and CBF might be maintained independently of nNOS by the reduction of nitrite to NO in the brain extracellular space upon neuronal activation (unpublish data). This innovative mechanism functionally links the production of NO from nitrite to neuronal activation, triggering CBF increases and maintaining an operative NVC. A further facet is that, bridging diet and cognitive performance, this mechanism incorporates modulatory elements which is open to adjustment by diet via nitrate. Thus, in this pilot trial a proof of concept study will be conducted to investigate the clinical impact of a dietary nitrate supplementation intervention in a clinical population with VCI due to small vessel disease, as measured by changes on NVC and cognitive performance. The investigators hypothesise that functional NVC is maintained operative in VCI patients by increasing NO bioavailability in the extracellular space of the brain through a nitrate -rich diet that, in turn, supports an adequate CBF in response to neuronal activation, modulating the molecular mechanisms and cognitive performance of disease-related physiological and cognitive markers.

The TELECONNECT-SVD study is a prospective, randomized, multicenter trial aimed at testing the efficacy of a remotely delivered exercise protocol on brain functional connectivity in patients with small vessel disease (SVD)-related ischemic stroke. The study will recruit patients aged ≥60 with a history of lacunar stroke, minimal disability (modified Rankin Scale score 0-1), and low physical activity levels. The trial will include 60 participants randomized 1:1 to either a 24-week telecoached exercise intervention or usual care. The exercise program consists of multicomponent physical exercises delivered remotely twice a week. Assessments will be conducted at baseline, 12 weeks, 24 weeks, and 48 weeks. Primary outcomes include changes in brain functional connectivity assessed by high-density EEG and improvements in physical fitness measured by the Senior Fitness Test. Secondary outcomes encompass changes in physical activity levels, anthropometric measurements, and vital signs. The study employs a "wait list" design, where the control group receives the intervention after the initial 24-week period. This approach allows for assessment of the intervention's immediate effects and the retention of benefits after cessation. Key features of the protocol include: * Use of telecoaching to enhance adherence to the exercise program * Comprehensive assessment of brain connectivity using advanced EEG analysis techniques * Focus on patients with SVD, who may benefit significantly from exercise interventions * Evaluation of both neurophysiological and clinical outcomes The study aims to provide evidence for the potential benefits of exercise in enhancing brain connectivity and physical fitness in SVD patients, potentially informing future treatment guidelines and preventive strategies for this population.

Lipid-lowering therapy constitutes a cornerstone of secondary prevention in ischemic stroke; however, current stroke guidelines remain deficient in providing optimal target low-density lipoprotein (LDL)-cholesterol levels tailored to the stroke subtypes. Most clinical trials on LDL-cholesterol management have not differentiated between stroke subtypes or have primarily focused on large artery atherosclerosis (LAA) stroke, leaving a gap in evidence for managing LDL-cholesterol in other stroke subtypes, e.g., small vessel occlusion (SVO) stroke. While hypertension is the leading risk factor for SVO strokes, the link between elevated LDL-cholesterol and SVO stroke is also recognized. Establishing optimal LDL-cholesterol targets for SVO stroke would significantly enhance secondary prevention strategies and improve patient outcome. Thus, the investigators aim to compare intensive versus standard lipid-lowering in patients with SVO stroke. SVO70 is a multicenter, prospective, randomized, open, blinded-endpoint clinical trial. Adult participants with objectively confirmed SVO stroke within 180 days of randomization will be included. Exclusion criteria include those with predefined LDL-cholesterol targets for other conditions, statin contraindications, or women who are pregnant, breastfeeding, or planning pregnancy during the study period. Eligible participants will be randomized 1:1 to target LDL-cholesterol \<70 mg/dL (intensive group) or 90-110 mg/dL (standard group). The trial plans to enroll 4,016 participants, with the primary outcome being major adverse cardiovascular events-cardiovascular death, stroke, and acute coronary syndrome-during a follow-up period of at least 4 years. This study would provide valuable information for determining the optimal LDL-cholesterol target for patients with SVO stroke.

Cerebral small vessel disease (cSVD) is a common accompaniment of aging. Recent small subcortical (or lacunar) infarcts (i.e. symptomatic cSVD) and white matter hyperintensities are typical cSVD lesions on neuroimaging. cSVD causes about a quarter of ischaemic strokes and related with cognitive dysfunction. However, few studies are available so far to especially explore the treatment of cSVD. Endothelial dysfunction plays an important part in cSVD. Cilostazol and isosorbide mononitrate have endothelial protective function. We designed this prospective cohort study in China, aiming to evaluate the effect of different antiplatelet agents (e.g. Cilostazol) on cSVD and retina in patients with cSVD (recent small subcortical infarcts or WMH, respectively).

Stroke is a major cause of death and disability worldwide, frequently resulting in persistent cognitive deficits among survivors. These deficits negatively impact recovery and therapy engagement, and their treatment is consistently rated as high priority by stakeholders and clinicians. Although clinical guidelines endorse cognitive screening for post-stroke management, there is currently no gold standard approach for identifying cognitive deficits after stroke, and clinical stroke services lack the capacity for long-term cognitive monitoring and care. Currently available assessment tools are either not stroke-specific, not in-depth or lack scalability, leading to heterogeneity in patient assessments. To address these challenges, a cost-effective, scalable, and comprehensive screening tool is needed to provide a stroke-specific assessment of cognition. The current study presents such a novel digital tool, the Imperial Comprehensive Cognitive Assessment in Cerebrovascular Disease (IC3), designed to detect both domain-general and domain-specific cognitive deficits in patients after stroke with minimal input from a health professional. To ensure its reliability, we will utilise multiple validation approaches, and aim to recruit a large normative sample of age-, gender-, and education-matched UK-based controls. Moreover, the IC3 assessment will be integrated within a larger prospective observational longitudinal clinical trial, where post-stroke cognition will be examined in tandem with brain imaging and blood biomarkers to identify novel multimodal biomarkers of recovery after stroke. By leveraging this rich dataset, our study will allow more precise targeting of cognitive rehabilitation to stroke survivors that are most at risk of progressive cognitive decline and have the greatest potential for recovery.

Prognosis of small vessel disease (SVD) depends on the underlying type of SVD and index manifestation. The aim of this prospective, observational cohort study is to determine the risk of different outcome events among patients with SVD according to the type of index presentation.