Increased white matter glycolysis in humans with cerebral small vessel disease

Pericytes and Extracellular Vesicle Interactions in Neurovascular Adaptation to Chronic Arterial Hypertension

BACKGROUND

Chronic arterial hypertension restructures the vascular architecture of the brain, leading to a series of pathological responses that culminate in cerebral small-vessel disease. Pericytes respond dynamically to vascular challenges; however, how they manifest under the continuous strain of hypertension has not been elucidated.

METHODS AND RESULTS

In this study, we characterized pericyte behavior alongside hypertensive states in the spontaneously hypertensive stroke-prone rat model, focusing on their phenotypic and metabolic transformation. Flow cytometry was used to characterize pericytes by their expression of platelet-derived growth factor receptor β, neuroglial antigen 2, cluster of differentiation 13-alanyl aminopeptidase, and antigen Kiel 67. Microvessels were isolated for gene expression profiling and in vitro pericyte expansion. Immunofluorescence validated the cell culture model. Plasma-derived extracellular vesicles from hypertensive rodents were applied as a treatment to assess their effects on pericyte function and detailed metabolic assessments on enriched pericytes measured oxidative phosphorylation and glycolysis. Our results reveal a shift in platelet-derived growth factor receptor β+ pericytes toward increased neuroglial antigen 2 and cluster of differentiation 13-alanyl aminopeptidase coexpression, indicative of their critical role in vascular stabilization and inflammatory responses within the hypertensive milieu. Significant alterations were found within key pathways including angiogenesis, blood-brain barrier integrity, hypoxia, and inflammation. Circulating extracellular vesicles from hypertensive rodents distinctly influenced pericyte mitochondrial function, evidencing their dual role as carriers of disease pathology and potential therapeutic agents. Furthermore, a shift toward glycolytic metabolism in hypertensive pericytes was confirmed, coupled with ATP production dysregulation.

CONCLUSIONS

Our findings demonstrate that cerebral pericytes undergo phenotypic and metabolic reprogramming in response to hypertension, with hypertensive-derived plasma-derived extracellular vesicles impairing their mitochondrial function. Importantly, plasma-derived extracellular vesicles from normotensive controls restore this function, suggesting their potential as both therapeutic agents and precision biomarkers for hypertensive vascular complications. Further investigation into plasma-derived extracellular vesicle cargo is essential to further explore their therapeutic potential in vascular health.

Anesthetics in pathological cerebrovascular conditions

The increasing prevalence of pathological cerebrovascular conditions, including stroke, hypertensive encephalopathy, and chronic disorders, underscores the importance of anesthetic considerations for affected patients. Preserving cerebral oxygenation and blood flow during anesthesia is paramount to prevent neurological deterioration. Furthermore, protecting vulnerable neurons from damage is crucial for optimal outcomes. Recent research suggests that anesthetic agents may provide a potentially therapeutic approach for managing pathological cerebrovascular conditions. Anesthetics target neural mechanisms underlying cerebrovascular dysfunction, thereby modulating neuroinflammation, protecting neurons against ischemic injury, and improving cerebral hemodynamics. However, optimal strategies regarding mechanisms, dosage, and indications remain uncertain. This review aims to clarify the physiological effects, mechanisms of action, and reported neuroprotective benefits of anesthetics in patients with various pathological cerebrovascular conditions. Investigating anesthetic effects in cerebrovascular disease holds promise for developing novel therapeutic strategies.

Increased White Matter Aerobic Glycolysis in Multiple Sclerosis

OBJECTIVE

Despite treatments which reduce relapses in multiple sclerosis (MS), many patients continue to experience progressive disability accumulation. MS is associated with metabolic disruptions and cerebral metabolic stress predisposes to tissue injury and possibly impaired remyelination. Additionally, myelin homeostasis is metabolically expensive and reliant on glycolysis. We investigated cerebral metabolic changes in MS and when in the disease course they occurred, and assessed their relationship with microstructural changes.

METHODS

This study used combined fluorodeoxyglucose (FDG) positron emission tomography (PET) and magnetic resonance imaging (MRI) to measure cerebral metabolic rate of glucose and oxygen, thereby quantifying glycolysis. Twelve healthy controls, 20 patients with relapsing MS, and 13 patients with non-relapsing MS were studied. Relapsing patients with MS were treatment naïve and scanned pre- and post-initiation of high efficacy disease modifying therapy.

RESULTS

In normal appearing white matter, we observed increased glucose utilization and reduced oxygen utilization in newly diagnosed MS, consistent with increased glycolysis. Increased glycolysis was greater in patients with a longer disease duration course and higher disability. Among newly diagnosed patients, different treatments had differential impacts on glucose utilization. Last, whereas hypermetabolism within lesions was clearly associated with inflammation, no such relationship was found within normal appearing white matter.

INTERPRETATION

Increased white matter glycolysis is a prominent feature of cerebral metabolism in MS. It begins early in the disease course, increases with disease duration and is independent of microstructural evidence of inflammation in normal appearing white matter. Optimization of the metabolic environment may be an important component of therapies designed to reduce progressive disability. ANN NEUROL 2024.

Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.