Search Results (439)

Type 2 Diabetes Mellitus (T2DM) is a recognized risk factor for Alzheimer’s Disease (AD), as epidemiological research indicates that those with T2DM have a markedly increased risk of experiencing cognitive decline and dementia. Chronic hyperglycemia and insulin resistance in T2DM hinder cerebral glucose metabolism, reducing the primary energy source for neurons and compromising synaptic function. Insulin resistance impairs signaling pathways crucial for neuronal survival and plasticity, while high insulin levels compete with amyloid-β (Aβ) for breakdown by insulin-degrading enzyme, promoting Aβ buildup. Additionally, vascular issues linked to T2DM impair blood–brain barrier functionality, decrease cerebral blood flow, and worsen neuroinflammation. Elevated oxidative stress and advanced glycation end-products (AGEs) in diabetes exacerbate tau hyperphosphorylation and mitochondrial dysfunction, worsening neurodegeneration. Collectively, these processes create a robust biological connection between T2DM and AD, emphasizing the significance of metabolic regulation as a possible treatment approach for preventing or reducing cognitive decline. Here, we review the relationship between T2DM and AD and discuss the roles insulin, hyperglycemia, and inflammation therapeutic strategies have in successful development of AD therapies. Additionally evaluated are recent therapeutic advances, especially involving the polyflavonoid anthocyanin, against T2DM-mediated AD pathology. Full article

Connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH) is a severe form of pulmonary hypertension with poor prognosis. It most commonly arises in systemic sclerosis (SSc), followed by systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Its pathogenesis involves a complex interplay of immune dysregulation, chronic inflammation, endothelial injury, vascular remodeling, and fibrosis. Although vasodilators targeting the endothelin, nitric oxide, and prostacyclin pathways remain the therapeutic backbone, newer agents—including the activin signal inhibitor sotatercept and inhaled treprostinil—have expanded treatment options. Immune-targeted therapies such as glucocorticoids, cyclophosphamide, mycophenolate mofetil, rituximab, and IL-6 receptor inhibitors may benefit inflammation-dominant PAH phenotypes, while fibrotic phenotypes continue to demonstrate limited responsiveness. In addition to brain natriuretic peptide (BNP), N-terminal (NT)-proBNP and disease-specific autoantibodies, emerging biomarkers show promise for early detection, risk stratification, and personalized treatment, though validation in CTD-PAH is lacking. Advances in animal models replicating immune-mediated vascular injury and fibrosis have further improved mechanistic understanding. Despite these developments, substantial unmet needs remain, including the absence of disease-specific therapeutic strategies, limited biomarker integration into clinical practice, and a scarcity of large, well-designed trials targeting individual CTD subtypes. Addressing these gaps will be essential for improving prognosis in patients with CTD-PAH. Full article

G protein-coupled receptors (GPCRs) are key regulators of cerebrovascular function, integrating vascular, inflammatory, and neuronal signaling within the neurovascular unit (NVU). Increasing evidence suggests that GPCR actions are highly dependent on cell type, signaling pathway, and disease stage, leading to distinct, and sometimes opposing, effects during acute ischemic injury and post-stroke recovery. In this review, we reorganize GPCR signaling mechanisms using a disease-stage-oriented and NVU-centered framework. We synthesize how GPCR-mediated intercellular communication among neurons, glial cells, and vascular elements dynamically regulates cerebral blood flow, neuroinflammation, blood–brain barrier (BBB) integrity, and neuronal circuit remodeling. Particular emphasis is placed on phase-dependent GPCR signaling, highlighting receptors whose functions shift across acute injury, secondary damage, and recovery phases. We further critically evaluated the translational implications of GPCR-targeted therapies, discussing why promising preclinical neuroprotection has frequently failed to translate into clinical benefit. By integrating molecular mechanisms with temporal dynamics and translational constraints, this review provides a framework for the rational development of cell-type and stage-specific GPCR-based therapeutic strategies in cerebrovascular disease. Full article

Background: Aging exerts a progressive and multifaceted impact on the microcirculatory system, undermining the structural and molecular integrity that sustains endothelial stability across both peripheral and cerebral vascular territories. A sustained shift toward oxidative imbalance, chronic low-grade inflammation, and progressive endothelial exhaustion converges to destabilize microvascular networks, linking peripheral artery disease (PAD) with heightened susceptibility to cerebral microvascular dysfunction and neurovascular decline. As redox homeostasis deteriorates, endothelial cells progressively lose barrier-selective properties, intercellular communication with pericytes weakens, and pro-thrombotic tendencies subtly emerge, creating a permissive environment for early neurovascular injury and impaired cerebrovascular resilience. Methods: This narrative review integrates mechanistic evidence derived from experimental, clinical, and translational studies examining the interplay between oxidative stress, inflammatory signaling cascades, endothelial senescence, and blood–brain barrier (BBB) disruption across peripheral and cerebral microvascular systems. A comparative framework was applied to PAD and cerebral microcirculatory pathology to identify convergent molecular drivers and systemic mechanisms underlying endothelial deterioration. Results: Accumulating evidence demonstrates that oxidative stress disrupts endothelial mitochondrial function, compromises tight junction architecture, and accelerates angiogenic failure. Concurrent inflammatory activation amplifies these alterations through cytokine-mediated endothelial activation, enhanced leukocyte adhesion, and promotion of a pro-thrombotic microenvironment. Progressive endothelial senescence consolidates these insults into a persistent state of microvascular dysfunction characterized by diminished nitric oxide bioavailability, capillary rarefaction, and compromised barrier integrity. Notably, these pathological features are shared between PAD and the aging cerebral circulation, reinforcing the concept of a unified systemic microvascular aging phenotype. Conclusions: Microvascular failure in the aging brain should be understood as an extension of systemic endothelial deterioration driven by oxidative stress, chronic inflammation, and senescence-associated vascular exhaustion. Recognizing the shared molecular architecture linking peripheral and cerebral microcirculatory dysfunction offers a strategic framework for developing targeted therapeutic interventions aimed at restoring endothelial resilience, stabilizing BBB integrity, and preserving neurovascular homeostasis in aging populations. Full article

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Since numerous studies highlight the significance of cholinergic system components in tumor development, acetylcholine (ACh) and the differential activation of its receptors could play a crucial role in GBM progression. The aim of this study was to test this hypothesis by assessing the relevance of the cholinergic system in GBM cells and their microenvironment. We analyzed bulk RNA-seq expression data using the TIMER2.0 web server, focusing on the impact of patient survival in relation to muscarinic receptors (CHRM) and neutrophil infiltration in low-grade glioma (LGG) and GBM. Our analysis revealed a marked decrease in survival associated with all CHRMs, particularly in LGG. Moreover, GBM showed higher neutrophil infiltration and reduced survival, especially in relation to CHRM3. These findings were validated in the U251 cell line and in human GBM tumor biopsies (GBM-b), which also displayed CHRM3 expression. Additionally, we show that GBM cells exposed to cholinergic stimulation exhibited increased vascular endothelial growth factor (VEGF), IL-8 production, and PD-L1 expression, while the VEGF increase was blocked by tiotropium (Tio), a CHRM3 antagonist. Similarly, polymorphonuclear cells from GBM patients (PMN-p) displayed increased PD-L1 expression and IL-8 production upon cholinergic stimulation. Finally, as we previously reported on the relevance of thymic stromal lymphopoietin (TSLP) in GBM pathophysiology, here, we found that TSLP upregulated CHRM3 expression. Our findings highlight the importance of the cholinergic system in the tumor microenvironment, where it may act directly on tumor cells or influence neutrophil physiology, thereby modulating tumor progression. Full article

Mixed dementia (MD), characterized by overlapping features of Alzheimer’s disease (AD) and vascular dementia (VaD), represents the most prevalent form of late-life cognitive decline. Increasing evidence identifies oxidative stress as a unifying molecular mechanism driving both neurodegenerative and vascular pathologies in MD. Reactive oxygen species (ROS) contribute to amyloid-β aggregation, tau hyperphosphorylation, endothelial dysfunction, and blood–brain barrier disruption, creating a self-perpetuating cycle of neuronal and vascular injury. Mechanistic models demonstrate how chronic hypoperfusion and mitochondrial dysfunction exacerbate ROS generation and neuroinflammation, while impaired Nrf2-mediated antioxidant defense further amplifies damage. Therapeutically, classical antioxidants show inconsistent efficacy, shifting focus toward mitochondrial protection, Nrf2 activation, and lifestyle-based oxidative load reduction. Therefore, we sought to outline therapeutic approaches capable of broadly targeting these mechanisms, through focused narrative analysis of recent studies employing delivery systems for antioxidant proteins and/or redox-regulating miRNAs. In particular, experimental interventions using mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) demonstrate neuroprotective and anti-inflammatory effects via the Nrf2 pathway, suggesting promising avenues for multimodal treatment. Integrating oxidative, vascular, and neurodegenerative paradigms is essential for advancing diagnostic precision and developing targeted interventions capable of addressing the complex pathophysiology of mixed dementia. Full article

Cognitive deterioration and the transition to neurodegenerative disease does not develop through simple, linear regression; it develops as rapid and global transitions from one state to another within the neural network. Developing understanding and control over these events is among the largest tasks facing contemporary neuroscience. This paper will discuss a conceptual reframing of cognitive decline as a transitional phase of the functional state of complex neural networks resulting from the intertwining of molecular degradation, vascular dysfunction and systemic disarray. The paper will integrate the latest findings that have demonstrated how the disruptive changes in glymphatic clearance mechanisms, aquaporin-4 polarity, venous output, and neuroimmune signaling increasingly correlate with the neurophysiologic homeostasis landscape, ultimately leading to the destabilization of the network attraction sites of memory, consciousness, and cognitive resilience. Furthermore, the destabilizing processes are exacerbated by epigenetic silencing; neurovascular decoupling; remodeling of the extracellular matrix; and metabolic collapse that result in accelerating the trajectory of neural circuits towards the pathological tipping point of various neurodegenerative diseases including Alzheimer’s disease; Parkinson’s disease; traumatic brain injury; and intracranial hypertension. New paradigms in systems neuroscience (connectomics; network neuroscience; and critical transition theory) provide an intellectual toolkit to describe and predict these state changes at the systems level. With artificial intelligence and machine learning combined with single cell multi-omics; radiogenomic profiling; and digital twin modeling, the predictive biomarkers and early warnings of impending collapse of the system are beginning to emerge. In terms of therapeutic intervention, the possibility of reprogramming the circuitry of the brain into stable attractor states using precision neurointervention (CRISPR-based neural circuit reprogramming; RNA guided modulation of transcription; lineage switching of glia to neurons; and adaptive neuromodulation) represents an opportunity to prevent further progression of neurodegenerative disease. The paper will address the ethical and regulatory implications of this revolutionary technology, e.g., algorithmic transparency; genomic and other structural safety; and equity of access to advanced neurointervention. We do not intend to present a list of the many vertices through which the mechanisms listed above instigate, exacerbate, or maintain the neurodegenerative disease state. Instead, we aim to present a unified model where the phenomena of molecular pathology; circuit behavior; and computational intelligence converge in describing cognitive decline as a translatable change of state, rather than an irreversible succumbing to degeneration. Thus, we provide a framework for precision neurointervention, regenerative brain medicine, and adaptive intervention, to modulate the trajectory of neurodegeneration. Full article

Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by persistent social communication difficulties, restricted interests, repetitive behaviors, and frequent medical comorbidities. Although early brain development in ASD has been extensively investigated, its biological progression across adulthood and aging remains largely unexplored. Growing evidence suggests that perivascular space (PVS) abnormalities may indicate impaired neurovascular integrity and reduced glymphatic clearance in ASD. Enlarged perivascular spaces (ePVS) in children commonly present alongside increased extra-axial CSF accumulation and more severe clinical manifestations, consistent with early alterations in CSF homeostasis and neuroimmune signaling. However, whether these abnormalities persist or evolve with aging remains unknown. Given that glymphatic and vascular integrity decline with age, and adults with ASD show elevated rates of sleep, metabolic, and cardiovascular disorders, PVS alterations may represent a unifying mechanism linking early neurodevelopmental divergence with later neurovascular vulnerability and cognitive aging. Advances in ultra-high-field MRI and automated segmentation now enable precise in vivo quantification of PVS burden, offering new opportunities for lifespan studies. By combining structural and functional methodologies, researchers may determine whether PVS constitute enduring traits, dynamic indicators of disease, or actionable therapeutic targets. Understanding their trajectories could provide critical insights into the continuum between neurodevelopmental and neurodegenerative phenomena in autism. Full article

Neurological disorders and cardiovascular disease (CVD) remain leading causes of global morbidity and mortality and often coexist, in part through shared mechanisms of chronic inflammation and oxidative stress. Neuroinflammatory signaling, including microglial activation, cytokine release, and impaired autonomic regulation, contributes to endothelial dysfunction, atherosclerosis, hypertension, and stroke, while cardiac and metabolic disturbances can reciprocally exacerbate brain pathology. Increasing evidence shows that several antidiabetic agents exert pleiotropic anti-inflammatory and antioxidant effects that extend beyond glycemic control. Metformin, SGLT2 inhibitors, DPP-4 inhibitors, and GLP-1 receptor agonists modulate key pathways such as AMPK, NF-κB, Nrf2 activation, and NLRP3 inflammasome suppression, with demonstrated vascular and neuroprotective actions in preclinical models. Clinically, GLP-1 receptor agonists and SGLT2 inhibitors reduce major cardiovascular events, improve systemic inflammatory markers, and show emerging signals for cognitive benefit, while metformin and DPP-4 inhibitors exhibit supportive but less robust evidence. This review synthesizes molecular, preclinical, and clinical data across drug classes, with particular emphasis on GLP-1 receptor agonists, and highlights outstanding translational questions including blood–brain barrier penetration, biomarker development, optimal patient selection, and timing of intervention. We propose a unified framework to guide future trials aimed at leveraging antidiabetic therapies such as DDP-4 anti-inflammatory and antioxidant interventions for neurological and cardiovascular diseases. Full article

Background: Referrals to the Stroke prevention clinic with incomplete preliminary investigations decrease clinic capacity due to additional workload and the need for multiple follow-ups. We aimed to improve the efficacy of the initial visit by increasing the completion rate of vascular imaging in a quality improvement (QI) project. Methods: This is a quasi-experimental study with three phases: Phase 1: Surveillance; Phase 2: Stakeholder feedback-informed intervention development (physicians and clinic staff); and Phase 3: Intervention. Interventions included a new standardized specific physician triage form listing required investigations (brain imaging, vascular imaging, cardiac tracing), and a nurse-led pre-visit via telephone. The primary outcome measure was the completion of vascular imaging by the time of visit, assessed using multivariable logistic regression adjusted for age (in years), sex, and triage category. Results: The study’s inclusion criteria were met by 397 patients, with a mean age of 67.7 ± 13.2 years; 47.8% were female, and 62.9% (250) were diagnosed with vascular events. An increase in vascular imaging before the initial visit was observed in Phase 3 (148/199, 75.5%) compared to Phase 1 (121/198, 61.1%), with an adjusted Odds ratio of 1.77 (95% CI 1.2–2.8; p = 0.01). A trend toward fewer follow-up visits was observed in Phase 3 (23.1%) compared with Phase 1 (31.8%; p = 0.052). Conclusions: Implementing a standardized triage process and a nurse-led pre-visit may improve completion of vascular imaging before patients visit the stroke prevention clinic. Further QI studies are required to improve the completion rate of rhythm monitoring in this patient group to enable early detection and management of atrial fibrillation. Full article

p17, the human immunodeficiency virus type 1 (HIV-1) matrix protein traditionally associated with viral assembly, has been recently investigated for its extracellular functions linked to vascular damage. This review examines the molecular and pathogenic signatures by which p17 and its variants (vp17s) contribute to endothelial activation, aberrant angiogenesis, and vascular inflammation, highlighting their relevance even under effective antiretroviral therapy (ART). Specifically, p17 exerts chemokine-like activities by binding to chemokine (C-X-C motif) receptor-1 and 2 (CXCR-1/2) on endothelial cells (ECs). This interaction triggers key signaling cascades, including the protein kinase B (Akt)-dependent extracellular signal-regulated kinase (ERK) pathway and endothelin-1/endothelin receptor B axis, driving EC motility, capillary formation, and lymphangiogenesis. Variants such as S75X demonstrate enhanced lymphangiogenic potency, associating them with tumorigenic processes involved in non-Hodgkin lymphoma (NHL) pathogenesis. Importantly, p17 promotes endothelial von Willebrand factor (vWF) storage and secretion, implicating a pro-coagulant state that may trigger the increased thromboembolic risks observed in HIV-positive patients. Furthermore, p17 crosses the blood–brain barrier (BBB) via CXCR-2-mediated pathways, contributing to neuroinflammation by activating microglia and astrocytes and amplifying monocyte chemoattractant protein-1 (MCP-1) levels, therefore playing a critical role in the development of HIV-associated neurocognitive disorders. Hence, the elaboration of potential therapeutic strategies finalized at inhibiting p17/vp17s’ interaction with their receptors could complement ART by addressing HIV-related neurovascular morbidity. Full article

Severe traumatic brain injury includes neurovascular unit (NVU) damage that is linked to the later development of neurodegenerative diseases. Cell-type-specific contributions and crosstalk between cells of the neurovascular unit following brain injury remain poorly defined in human cells. Here, we developed a three-dimensional (3D) human NVU model using silk–collagen scaffolds to examine cellular responses to controlled cortical impact (CCI). Using this platform, we show that CCI induced acute cell death in astrocytes, microglia, and endothelial cells but spared pericytes, which occurred independently of classical apoptotic or necroptotic pathways. Astrocytes and microglia were the primary sources of early bioactive IL-1β release, while endothelial junctional integrity was differentially regulated by support cells: astrocytes destabilized VE-cadherin, pericytes preserved barrier proteins, and microglia contributed to Claudin-5 loss in multicellular settings. Conditioned media experiments demonstrated that soluble factors from injured support cells alone were sufficient to disrupt endothelial junctional proteins (ZO-1 and Occludin) and induce inflammatory adhesion molecules (ICAM-1 and VCAM-1). Together, these findings define cell-type-specific injury responses and reveal how NVU interactions regulate vascular dysfunction after trauma, providing a human-based framework for understanding blood–brain barrier (BBB) disruption following traumatic brain injury (TBI). Full article

Melanoma cells in the brain may use similar mechanisms for adapting to injury and/or disease (that is, through continued reallocation of energy, matter, and information) as other cell types do to create an environment in which cancer cells can grow and sustain themselves within the confines of the brain. These adaptable mechanisms include the ability to reactivate dormant neural crest-derived migration and communication pathways. Unlike some other types of cancers that invade neural tissue as a simple invasion, melanomas are capable of achieving limited molecular, metabolic, and electrical similarity to the neural circuitry of the brain. Melanomas achieve this limited similarity through both vascular co-optation and mimicking synaptic functions, as well as through their engagement of redox-coupled metabolic pathways and feedback-regulated signal transduction pathways. The result is the creation of a metastable tumor–host system, where the relationship between tumor and host is defined by the interaction of stabilizing and destabilizing forces; forces that define the degree of coherence, vulnerability, and persistence of the tumor–host system. In this review, we integrate molecular, electrophysiological, and anatomical data to develop a single unifying hypothesis for the functional integration of melanoma cells into the neural tissue of the brain. Additionally, we describe how neural crest-based regulatory pathways are reactivated in the adult brain and how tumor–host coherence is developed as a function of the shared thermodynamic and informational constraints placed on both tumor and host. We also describe how our proposed conceptual model allows for the understanding of therapeutic interventions as selective disruptions of the neural, metabolic, and immunological couplings that support metastatic adaptation. Full article

The way in which Aquaporin-4 (AQP4) is localized on the astrocytes’ surface—i.e., with AQP4 channels predominantly located on the endfeet of astrocytes near the blood vessels—represents an important structural element for maintaining brain fluid homeostasis. In addition to this structural function, AQP4 polarity also facilitates glymphatic transport, the maintenance of the blood–brain barrier (BBB) functions, ion buffering, and neurotransmitter removal, and helps regulate neurovascular communications. The growing body of literature suggests that the loss of AQP4 polarity—a loss in the organization of AQP4 channels to the perivascular membrane—is associated with increased vascular, inflammatory, and metabolic disturbances in the context of many neurological diseases. As a result, this review attempts to synthesize both experimental and clinical studies to highlight that AQP4 depolarization often occurs in conjunction with early signs of neurodegeneration and neuroinflammation; however, we are aware that the loss of AQP4 polarity is only one factor in a complex pathophysiological environment. This review examines the molecular structure responsible for maintaining the polarity of AQP4—such as dystrophin–syntrophin complexes, orthogonal particle arrays, lipid microdomains, trafficking pathways, and transcriptional regulators—and describes how the vulnerability of these systems to various types of vascular stress, inflammatory signals, energy deficits, and mechanical injury can lead to a loss of AQP4 polarity. Furthermore, we will explore how a loss of AQP4 polarity can lead to the disruption of perivascular fluid movement, changes in blood–brain barrier morphology, enhanced neuroimmune activity, changes in ionic and metabolic balance, and disruptions in the global neural network synchronization. Importantly, we recognize that each of these disruptions will likely occur in concert with other disease-specific mechanisms. Alterations in AQP4 polarity have been observed in a variety of neurological disorders including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, traumatic brain injury, and glioma; however, we also observe that the same alterations in fluid regulation occur across all of these different diseases, but that no single upstream event accounts for the alteration in polarity. Ultimately, we will outline emerging therapeutic avenues to restore perivascular fluid transport, and will include molecular-based therapeutic agents designed to modify the anchoring of AQP4, methods designed to modulate the state of astrocytes, biomaterials-based drug delivery systems, and therapeutic methods that leverage dynamic modulation of the neurovascular interface. Future advances in multi-omic profiling, spatial proteomics, glymphatic imaging, and artificial intelligence will allow for earlier identification of AQP4 polarity disturbances and potentially allow for the development of more personalized treatment plans. Ultimately, by linking these concepts together, this review aims to frame AQP4 polarity as a modifiable aspect of the “fluidic connectome”, and highlight its importance in maintaining overall brain health across disease states. Full article

Background: Stereotactic radiosurgery (SRS) was originally conceived as a noninvasive alternative to functional neurosurgery by the Swedish neurosurgeon Lars Leksell. This review traces the historical development of stereotactic methods from early mechanical frames to advanced image-guided systems and examines the pivotal innovations that enable precise intracranial targeting for SRS. Methods: Using PubMed and Google Scholar, we reviewed the literature on the general history of functional stereotactic neurosurgery and radiosurgery, its indications, and how their treatment methods evolved, focusing mainly on the early period from the end of the 18th century to the 1990s. Results: The origins of stereotaxy as a principle and technique were traced back to the early 20th century with animal studies by Horsley and Clarke, later adapted for human use by Spiegel and Wycis, and then Talairach in the 1940s. This enabled the precise targeting of deep brain structures for lesion-based interventions in movement, pain, and psychiatric disorders. Deep Brain Stimulation (DBS) emerged in the 1980s as a reversible treatment for tremor. Stereotactic radiosurgery was conceived in 1951 as a noninvasive alternative functional approach and saw limited use until the 1990s due to imaging constraints. With MRI-guided planning, its application has expanded mostly to the management of benign and malignant tumors and vascular disorders, as well as for functional approaches, particularly for trigeminal neuralgia, tremor, epilepsy, and OCD. Conclusions: This review underscores how technological progress and shifting clinical priorities have transformed SRS from a niche neurosurgical technique into a cornerstone of modern clinical practice, with functional SRS representing its latest clinical field of expansion. Full article