Search Results (485)

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

Organoids consisting of primary human cells, i.e., astrocytes, pericytes, and endothelial cells, form a functional blood–brain barrier (BBB) in vitro. The ability of FITC-dextran (70 kDa), calcium phosphate nanoparticles (100 nm), Escherichia coli bacteria (2 µm), and MS2 coliphages (27 nm, a model for viruses) to penetrate the BBB under normoxic and hypoxic conditions (2.5% oxygen) for up to 12 days was assessed by fluorescence microscopy and confocal laser scanning microscopy. All agents were fluorescently labeled to trace them inside the organoids. Under normoxia, FITC-dextran, calcium phosphate nanoparticles, E. coli bacteria and MS2 coliphages did not penetrate the BBB. However, oxygen deficiency (hypoxia) triggered the penetration of the BBB by FITC-dextran and E. coli cells. This was underscored by a strong hypoxic center inside the organoids that developed in the presence of E. coli bacteria. Full article

Evidence on the therapeutic use of nanoparticles for traumatic brain injury (TBI) remains limited. This study aimed to evaluate the neuroprotective potential of atorvastatin-loaded polyethylene glycol (PEG)-conjugated liposomes (LipoStatin) in a mouse model of repetitive TBI. TBI was induced using five controlled head impacts with a 120 g weight at 12-h intervals. Mice were randomly assigned to Sham, Control (saline-treated), Statin (free atorvastatin), Liposome (empty PEGylated liposomes without atorvastatin), and LipoStatin (atorvastatin-loaded PEGylated liposome) groups. LipoStatin (10 mg/kg/day) was intravenously administered for 5 days post-injury. Neurological function was evaluated using the neurological severity score (NSS), while blood–brain barrier (BBB) integrity and neuroinflammation were assessed on day 5, and cellular apoptosis on day 12. LipoStatin-treated mice exhibited the lowest NSSs. IVIS^® imaging indicated significantly attenuated BBB disruption (p < 0.001), and Western blot analysis revealed restored caveolin-1 protein levels (p < 0.01), which are associated with BBB integrity. TNF-α levels were reduced considerably in the LipoStatin group compared to both the Control (p < 0.001) and Statin (p < 0.05) groups. Immunofluorescence showed reduced co-localization of caspase-3 with PDGFR-β and GFAP, indicating decreased pericyte and astrocyte apoptosis. These findings suggest that LipoStatin may confer neuroprotection in TBI by stabilizing BBB integrity, reducing inflammation, and mitigating cell death, supporting its potential as an improved nanocarrier-based therapeutic approach. Full article

Neurodegenerative diseases pose major clinical challenges partly due to the underappreciation of the brain’s vascular and clearance systems. Evidence suggests that neurovascular dysfunction and glymphatic impairment are early contributors to disease onset, preceding established markers such as protein aggregation. This review synthesizes recent advances in understanding how disruption of the neurovascular unit (NVU) and glymphatic pathways contributes to neurodegeneration. We analyzed published literature documenting the temporal relationship between vascular dysfunction, glymphatic clearance impairment, and subsequent neurodegenerative pathology, with a focus on identifying therapeutic targets within this axis. Current research demonstrates that blood-brain barrier BBB breakdown, pericyte dysfunction, and compromised cerebral perfusion precede protein aggregation in multiple neurodegenerative disorders. Glymphatic dysfunction, characterized by aquaporin-4 (AQP4) depolarization and abnormalities in meningeal lymphatic vessels, impairs the clearance of neurotoxic metabolites. Novel therapeutic opportunities include the preservation of pericyte function, restoration of AQP4 polarity, enhancement of meningeal lymphatic drainage via vascular endothelial growth factor-C (VEGF-C)/vascular endothelial growth factor receptor-3 VEGFR-3 signaling, and targeted modulation of microRNA and complement pathways that regulate neuroinflammation. By targeting the earliest vascular and glymphatic disruptions, emerging therapeutic strategies may halt or delay disease progression before irreversible neuronal loss occurs. This neurovascular-glymphatic approach represents an unexplored frontier that complements traditional protein-centric therapeutic paradigms, offering new possibilities for early intervention in neurodegenerative disorders. Full article

Background and Clinical Significance: Tyrosine kinase inhibitors (TKIs) have transformed Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML) into a largely manageable chronic disease. However, off-target toxicities are increasingly recognized; rarer complications such as bone marrow edema (BME) remain underreported. BME is a radiological syndrome characterized by excess intramedullary fluid on fat-suppressed T2/STIR magnetic resonance imaging sequences and may progress to irreversible osteochondral damage if unrecognized. We report a case series of TKI-associated BME and propose a practical diagnostic-therapeutic framework. Case Presentation: We describe three patients with Ph+ CML who developed acute, MRI-confirmed BME of the lower limb during TKI therapy. Case 1 developed unilateral then bilateral knee BME, temporally associated first with dasatinib and subsequently with imatinib; symptoms improved after TKI interruption, bisphosphonate therapy, and supportive measures, and did not recur after switching to bosutinib. Case 2 presented with proximal femoral BME during long-term imatinib; imatinib was stopped, intravenous neridronate administered, and bosutinib initiated with clinical recovery and later near-complete radiological resolution. Case 3 experienced multifocal foot and ankle BME during imatinib; symptoms resolved after drug discontinuation and bisphosphonate therapy, and disease control was re-established with bosutinib without recurrence of BME. All patients underwent molecular monitoring and mutational analysis to guide safe therapeutic switching. Discussion: Temporal association across cases and the differential kinase profiles of implicated drugs suggest PDGFR (and to a lesser extent, c-KIT) inhibition as a plausible mechanistic driver of TKI-associated BME. PDGFR-β blockade may impair pericyte-mediated microvascular integrity, increase interstitial fluid extravasation, and alter osteoblast/osteoclast coupling, promoting intramedullary edema. Management combining MRI confirmation, temporary TKI suspension, bone-directed therapy (bisphosphonates, vitamin D/calcium), symptomatic care, and, when required, therapeutic switching to a PDGFR-sparing agent (bosutinib) led to clinical recovery and preservation of leukemia control in our series. Conclusions: BME is an underrecognized, potentially disabling, TKI-related adverse event in CML. Prompt recognition with targeted MRI and a multidisciplinary, stepwise approach that includes temporary TKI adjustment, bone-directed therapy, and consideration of PDGFR-sparing alternatives can mitigate morbidity while maintaining disease control. Prospective studies are needed to define incidence, risk factors, optimal prevention, and management strategies. 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

Brain function is reliant upon maintaining a constant internal environment; however, the methods employed to maintain this environment have historically been viewed as largely passive in nature, relying on diffusion and vascular pulsations to create the conditions necessary for continued brain activity. This review seeks to provide an overview of current data suggesting that brain clearance is in fact an active process that is dependent upon both the current regulatory state of the brain and the presence of noradrenergic slow vasomotion, which is generated by rhythmic output from the locus coeruleus (LC). The LC-generated output has been found to influence the degree of contraction exhibited by pericytes, the geometric shape of astrocytic end-feet, and vascular tone, ultimately impacting the rate of exchange between cerebrospinal fluid (CSF), interstitial fluid (ISF), and the blood–brain barrier through aquaporin-4 (AQP4) channels. These LC-generated rhythmic changes are thought to provide the mechanical forces necessary for sustaining the metabolic clearance of waste products within the parenchyma. This review seeks to synthesize several recent studies which indicate that LC-generated vasomotion correlates with both the structure and progression of sleep states, neuronal oscillation patterns, and metabolic states, and that dysfunction of this LC-generated rhythm may contribute to pathological features associated with Alzheimer’s disease, Parkinson’s disease, and small-vessel disease. Understanding the mechanisms of clearance within the brain as a physiologically tunable system will allow researchers to view brain clearance as an adaptive neuro-modulatory function rather than merely as a passive event. Therefore, the focus of this review is on identifying the potential applications of advancements in the field of physiological imaging, molecular biomarkers, and neuro-modulatory or vascular-based therapies for early detection and therapeutic manipulation of clearance processes. Understanding these mechanisms will potentially lead to enhanced cognitive resilience and immune regulation, and promote healthy brain aging. Full article

Tau pathology is a defining hallmark of Alzheimer’s disease (AD), closely associated with cognitive decline. Antisense oligonucleotides targeting the tau-encoding gene MAPT (MAPT-ASO) have shown promise in clinical trials, but their therapeutic potential is limited by poor delivery across the blood–brain barrier (BBB). In this study, we developed transferrin (TF)-functionalized liposomes encapsulating MAPT-ASOs and evaluated their transport across a 3D self-assembled microvascular BBB model composed of human brain microvascular endothelial cells, astrocytes, and pericytes embedded in a fibrin hydrogel. Following confirmation of MAPT-ASO efficacy in reducing tau levels and protecting against glutamate-induced axonal degeneration, we observed significantly enhanced extravascular accumulation and sustained delivery of MAPT-ASOs with TF-functionalized liposomes over 24 h, compared to non-functionalized control liposomes. This study presents a novel delivery strategy for a functionally effective tau-targeting anti-sense oligonucleotide (ASO), potentially enabling systemic delivery rather than intrathecal administration. In addition, this study demonstrates the utility of the 3D in vitro BBB model for screening and optimizing brain delivery of nucleic acid-based therapeutics. Full article

The tumour microenvironment in pancreatic ductal adenocarcinoma (PDA) regulates vascular function and therapeutic response. P21-activated kinases (PAKs) regulate cytoskeletal dynamics and angiogenesis; however, their roles in vascular reprogramming and chemotherapy responses remain unclear. This study examined the effects of a PAK1 knockdown (PAK1KD) and a PAK4 knockout (PAK4KO) on vascular remodelling in PDA. Human PANC-1 wild-type (WT), PAK1KD, and PAK4KO cells were injected subcutaneously into the flanks of SCID mice followed gemcitabine treatment. The tumour growth, vascular density, pericyte coverage, adhesion molecules, and hypoxia were determined. A proteomics study was used to identify the molecular changes involved in the vascular pathways. PAK1KD suppressed tumour growth and angiogenesis, promoted vascular normalisation, reduced hypoxia, and increased stromal ICAM-1. PAK4KO inhibited tumour growth, enlarged vessels, enhanced angiogenesis, and reduced hypoxia. PAK4KO did not affect adhesion molecules in the absence of gemcitabine, but markedly upregulated ICAM-1 and VCAM-1 with gemcitabine. Additionally, PAK4KO promoted vascular mimicry (VM) with a compromised integrity in tumour-derived vessels, but enhanced the integrity in endothelial-derived vessels. The proteomics study confirmed the enrichment of molecules in fibronectin and the VEGF pathway in PAK4KO cancer cells, along with the upregulation of EphA2, RhoA, ROCK1, ROCK2, and components of the EPH-ephrin signalling pathway, linking to enhanced VM. Neither PAK1KD nor PAK4KO increased the gemcitabine efficacy. In conclusion, PAK1KD and PAK4KO suppressed tumour growth with distinct vascular effects, but failed to enhance the gemcitabine responses, suggesting that PAK targeting reprograms the PDA vasculature, but offers limited benefit in chemotherapy-resistant models. Full article

Ischemic stroke remains one of the most catastrophic diseases in neurology, in which, due to a disturbance in the cerebral blood flow, the brain is acutely deprived of its oxygen and glucose oligomer, which in turn rapidly leads to energetic collapse and progressive cellular death. There is now increasing evidence that this type of stroke is not simply a type of ‘oxidative stress’ but rather a programmable loss-of-redox homeostasis, within which electron flow and the balance of oxidants/reductants are cumulatively displaced at the level of the single molecule and at the level of the cellular area. The advances being made in cryo-electron microscopy, lipidomics, and spatial omics are coupled with the introduction of a redox code produced by the interaction of the couples NADH/NAD⁺, NADPH/NADP⁺, GSH/GSSG, BH₄/BH₂, and NO/SNO, which determine the end results of the fates of the neurons, glia, endothelium, and pericytes. Within the mitochondria, pathophysiological events, including reverse electron transport, succinate overflow, and permeability transition, are found to be the first events after reperfusion, while signals intercommunicating via ER–mitochondria contact, peroxisomes, and nanotunnels control injury propagation. At the level of the tissue, events such as the constriction of the pericytes, the degradation of the glycocalyx, and the formation of neutrophil extracellular traps underlie microvascular failure (at least), despite the effective recanalization of the vessels. Systemic influences such as microbiome products, oxidized lipids, and free mitochondrial DNA in cells determine the redox imbalance, but this generally occurs outside the brain. We aim to synthesize how the progressive stages of ischemic injury evolve from the cessation of flow to the collapse of the cell structure. Within seconds of injury, there is reverse electron transport (RET) through mitochondrial complex I, with bursts of superoxide (O₂•⁻) and hydrogen peroxide (H₂O₂) being produced, which depletes the stores of superoxide dismutase, catalase, and glutathione peroxidase. Accumulated succinate and iron-induced lipid peroxidation trigger ferroptosis, while xanthine oxidase and NOX2/NOX4, as well as uncoupled eNOS/nNOS, lead to oxidative and nitrosative stress. These cascades compromise the function of neuronal mitochondria, the glial antioxidant capacity, and endothelial–pericyte integrity, leading to the degradation of the glycocalyx with microvascular constriction. Stroke, therefore, represents a continuum of redox disequilibrium, a coordinated biochemical failure linking the mitochondrial metabolism with membrane integrity and vascular homeostasis. Full article

Background/Objectives: To elucidate the differential transcriptional and intercellular signaling features of tumor components across various cancers, we conducted a comparative analysis using single-cell RNA sequencing (scRNA-seq). This technology enables detailed characterization of tumor ecosystems and may explain variations in tumor behavior among distinct cancer types. Methods: We analyzed publicly available scRNA-seq datasets (GEO) from seven cancer types—pancreatic ductal adenocarcinoma (PDAC), hepatocellular carcinoma (HCC), esophageal squamous cell carcinoma (ESCC), breast cancer (BC), thyroid cancer (TC), gastric cancer (GC), and colorectal cancer (CRC)—to define their unique molecular characteristics and intercellular interactions. Results: PDAC displayed a distinct tumor microenvironment (TME) dominated by myeloid cells (~42%), including abundant CXCR1/CXCR2-expressing tumor-associated neutrophils (TANs) that preferentially interacted with immune rather than cancer cells. The competitive receptor ACKR1 was minimally expressed on endothelial cells, consistent with PDAC hypo-vascularity. In HCC, tumor cells lacked EPCAM and expressed complement and stem cell markers; cancer-associated fibroblasts (CAFs) were scarce, and stellate cells expressed the pericyte marker RGS5. CAFs were abundant in ESCC and BC, with IGF1/2 expression, while in GC, these markers were uniquely found in plasma cells. Since BC and GC subtypes exhibit distinct TME patterns, it is necessary to perform subtype-specific analyses for these cancers. TC showed high expression of tumor-suppressor genes, including HOPX, in tumor cells. Differential interactions and the presence of “dominant signaling cell populations “ with dominant outgoing signals may underlie the heterogeneity in tumor aggressiveness across these cancers. Conclusions: Comparative scRNA-seq analysis of multiple cancers reveals distinct tumor phenotypes and cell–cell communication patterns, offering insights into the molecular architecture of human solid tumors. Full article

Background/Objectives: The tumour microenvironment in pancreatic ductal adenocarcinoma (PDA) is highly complex, influencing both vascular function and therapy response. P21-activated kinases (PAKs) are key regulators of the cellular and immune system, but the specific roles of PAK1 and PAK4 in pancreatic tumour vasculature and chemotherapy sensitivity are unclear. This study investigated the effects of PAK1 and PAK4 on tumour vasculature and therapeutic response in an immunocompromised mouse model. Methods: KPC-derived wild type (WT), PAK1 knockout (KO), PAK4KO, or PAK1&4KO pancreatic cancer cells were injected subcutaneously into SCID mice, followed by gemcitabine treatment. Tumour growth, vessel density, pericyte coverage, and endothelial adhesion molecule expression were analysed by histology and immunostaining. A proteomic study was used to identify protein changes. Results: PAK1KO significantly reduced tumour growth, enhanced vascular normalisation, upregulated stromal ICAM-1 and VCAM-1, but reduced gemcitabine efficacy. PAK4KO did not inhibit tumour growth but increased vessel diameter and enhanced gemcitabine efficacy. Proteomics study indicated that PAK1KO downregulated proteins involved in the VEGF pathway, while PAK4KO upregulated most proteins involved in the VEGF pathway and downregulated DNA repair proteins, contributing to improved chemotherapy sensitivity. The double knockout of PAK1 and PAK4 did not inhibit tumour growth, although it stimulated vascular normalisation, indicating an outcome balanced between PAK1 and PAK4. Conclusions: PAK1 and PAK4 differentially regulated pancreatic tumour vasculature and chemotherapy response. PAK1KO suppressed tumour growth by reducing angiogenesis and enhancing vascular normalisation, whereas PAK4KO enhanced gemcitabine efficacy through vessel dilation. Full article

A functional blood vessel network is required to deliver oxygen and nutrients to the cancer cells for their growth. Angiogenesis, the formation of new blood vessels from pre-existing ones, is one of the major mechanisms to create this vascular network. Anti-angiogenic therapy was conceived as the inhibition of the cellular and molecular players involved in tumor angiogenesis such as vascular endothelial growth factor and its main receptors. Due to limitations of this therapy, different approaches of vessel modulation such as vascular normalization or vascular promotion have been studied showing benefits in different tumor models and clinical trials. In contrast to anti-angiogenic therapy, which inhibits the blood vessels that are being formed, vascular disruption therapy aims to destroy already formed tumor vessels. These malignant vascular structures differ from other blood vessels in terms of endothelial cell states, pericyte coverage and basement membrane development. The molecules used for vascular disruption are microtubule-binding molecules, flavonoids that induce endothelial cell apoptosis or molecules vectorized to endothelial receptors. Many vascular disruption agents have been tested in clinical trials showing some promising results, but with some limitations that include resistant rim cells or the development of hypoxia that induces cancer regrowth and poor delivery of the anti-tumor agents. The main objective of this review is to focus on vascular disruption agents therapy, novel molecules, new ways to overcome therapy resistance to them, current clinical status and, especially, the upcoming challenges and applications of these molecules. Full article

Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment (TME) that influence cancer progression via extracellular matrix (ECM) remodeling and secretion of growth factors and cytokines. Endothelial-to-mesenchymal transition (EndMT) is emerging as an important axis among the heterogeneous origins of CAFs. This review introduces the diverse methods used to induce EndMT in cancer—mouse tumor models, conditioned-medium treatment, co-culture, targeted gene perturbation, ligand stimulation, exosome exposure, irradiation, viral infection, and three-dimensional (3D) culture systems—and summarizes EndMT cell-type evidence uncovered using transcriptomic and proteomic technologies. Hallmark EndMT features include spindle-like morphology, increased motility, impaired angiogenesis and barrier function, decreased endothelial markers (CD31, VE-cadherin), and increased mesenchymal markers (α-SMA, FN1). Reported mechanisms include signaling via TGF-β, cytoskeletal/mechanical stress, reactive oxygen species, osteopontin, PAI-1, IL-1β, GSK-3β, HSP90α, Tie1, TNF-α, HSBP1, and NOTCH. Cancer-induced EndMT affects tumors and surrounding TME—promoting tumor growth and metastasis, expanding cancer stem cell-like cells, driving macrophage differentiation, and redistributing pericytes—and is closely associated with poor survival and therapy resistance. Finally, we indicate each study’s stance: some frame cancer-induced EndMT as a source of CAFs, whereas others, from an endothelial perspective, emphasize barrier weakening and promotion of metastasis. Full article

Cerebral vasospasm (CVS) following a subarachnoid hemorrhage (SAH) is a critical complication driven by imbalances between vasodilators and vasoconstrictors. This review explores the bidirectional interplay between nitric oxide (NO) and endothelin-1 (ET-1) in CVS pathogenesis. NO, a potent vasodilator mainly produced by endothelial and neuronal nitric oxide synthase (eNOS/nNOS) under normal physiological conditions, is scavenged early after SAH by hemoglobin derivatives, leading to microcirculatory dysfunction, pericyte constriction, and impaired neurovascular coupling. Conversely, ET-1 exacerbates vasoconstriction by suppressing NO synthesis via ROS-dependent eNOS uncoupling and Rho-kinase activation. The NO/ET-1 axis further influences delayed cerebral ischemia (DCI) through mechanisms like 20-HETE-mediated cGMP suppression and oxidative stress. Emerging therapies—including NO donors, NOS gene therapy, and ET-1 receptor antagonists—aim to restore this balance. Understanding these pathways offers translational potential for mitigating CVS and improving outcomes post-SAH. Full article