Astrocyte Responses to Obesity May Disrupt Blood Pressure Control

Obesity-induced hypertension is more than a peripheral vascular problem: a 2026 review argues that reactive astrocytes may help translate excess adiposity, inflammation and metabolic stress into sustained sympathetic nervous system activity. Published in Frontiers in Neuroscience, the review connects evidence from animal experiments, cell studies and human neuroimaging to propose that astrocytes in the hypothalamus and brainstem become reactive in obesity. Their altered handling of glutamate, inflammatory signaling and relationships with blood vessels may then disturb neural circuits that regulate blood pressure. The authors emphasize that direct causal evidence linking astrocyte dysfunction to hypertension specifically in obesity remains limited, making this a mechanistic framework rather than a clinically proven pathway.

The scale of the problem is substantial. The review reports that an estimated 2.5 billion adults worldwide were overweight in 2022, including more than 890 million living with obesity. High body mass index is associated with cardiovascular disease, diabetes, cancer and other conditions, and the review cites an estimated 3.7 million deaths linked to elevated BMI in 2021. In the United States, the proportion of adults with both obesity and hypertension increased from 39.6% in 2001 to 55.4% in 2023. Obesity-induced hypertension is a multifactorial phenotype involving sympathetic activation, altered renal sodium handling, renin-angiotensin-aldosterone system activation, insulin resistance, endothelial dysfunction and chronic inflammation. Yet peripheral mechanisms alone do not explain why blood pressure remains elevated in many people with obesity.

That unresolved component has drawn attention to central autonomic networks, especially the hypothalamic arcuate nucleus, paraventricular nucleus of the hypothalamus, nucleus tractus solitarius and rostral ventrolateral medulla. These regions integrate metabolic, hormonal and cardiovascular information. Leptin is a key signal in this process because its levels generally rise with fat mass and activate hypothalamic pathways that can increase sympathetic outflow and arterial pressure. The review describes a form of selective leptin resistance in obesity: leptin’s effects on appetite and energy expenditure may become impaired while its cardiovascular effects on sympathetic activity remain intact. Persistent activation of sympathetic pathways can increase vasoconstriction, heart rate and renal sodium reabsorption, supporting sustained elevations in blood pressure.

Astrocytes provide a possible connection between circulating signals and the neurons that control autonomic output. These abundant central nervous system glia regulate extracellular glutamate, buffer potassium, support neuronal energy metabolism, maintain the blood–brain barrier and couple neural activity to blood flow. Under obesogenic conditions, the review says, excess nutrients, circulating saturated fatty acids such as palmitic acid, adipokines and inflammatory mediators can induce astrogliosis in autonomic regions. Reactive astrocytes undergo structural and molecular changes, including increased glial fibrillary acidic protein expression and greater release of pro-inflammatory cytokines. The resulting environment is one of chronic neuroinflammation rather than a simple loss of supportive glial function.

Glutamate regulation may be one of the most consequential links between astrocyte reactivity and sympathetic activation. Glutamate is the main excitatory neurotransmitter in the central nervous system, and excitatory amino acid transporters rapidly remove it from the synaptic cleft. EAAT1 and EAAT2 are predominantly astrocytic, whereas EAAT3, EAAT4 and EAAT5 are primarily neuronal. Astrocytically captured glutamate is converted to glutamine, returned to neurons and converted back to glutamate, forming the glutamate–glutamine cycle. If EAAT2-dependent uptake is impaired, extracellular glutamate can accumulate, increasing neuronal excitability and potentially strengthening excitatory drive in cardiovascular control circuits. Astrocyte-derived gliotransmitters, including ATP and D-serine, may further influence synaptic transmission in those networks.

The proposed pathway also includes oxidative stress, mitochondrial dysfunction and inflammatory signaling inside astrocytes. Palmitic acid exposure has been associated in experimental systems with endoplasmic reticulum stress, impaired mitochondria, reactive oxygen species production and lipid accumulation. These cellular stresses can activate the IKKβ/NF-κB pathway, increasing cytokines such as TNF-α, IL-1β and IL-6. The review further links astrocyte-driven neuroinflammation with central renin-angiotensin-aldosterone system activation and reduced baroreflex sensitivity. Because astrocytes also participate in neurovascular coupling and blood–brain barrier maintenance, their dysfunction may allow additional inflammatory mediators and metabolic substrates to enter the brain, creating a cycle of inflammation and autonomic imbalance.

Some experimental results make the proposed connection more concrete, although they do not establish an obesity-specific causal mechanism. The review highlights single-nucleus RNA-sequencing work identifying distinct astrocyte populations in the rostral ventrolateral medulla of spontaneously hypertensive rats. Increased expression of contactin-associated protein-like 2, or Cntnap2, was associated with lower EAAT2 expression and reduced glutamate uptake; neuronal excitability, sympathetic outflow and blood pressure increased in the same model. This finding was not produced in an obesity model, and it remains unknown whether obesity causes comparable astrocyte-specific changes in that region or in other autonomic nuclei. Most other evidence comes from hypothalamic metabolic studies, cultured cells or hypertension models that are not specific to obesity. Human neuroimaging supports an association between obesity and hypothalamic gliosis, but there is little direct evidence of astrocyte dysfunction in human cardiovascular regulatory regions.

The review examines several possible intervention strategies while distinguishing laboratory compounds from established clinical therapies. Arundic acid has increased EAAT1 expression and glutamate uptake in experimental studies and has also reduced markers of oxidative stress, neuroinflammation and reactive astrogliosis. The review states that it is not yet commercially available and that much of the work has involved mice. Butein, a dietary flavonoid, and berberine have shown anti-inflammatory and antioxidant effects in experimental models that may be relevant to astrocyte dysfunction. These findings indicate biological activity, not demonstrated treatment of obesity-induced hypertension in people. Clinical studies have not established that either compound controls blood pressure through astrocyte-specific mechanisms.

GLP-1 receptor agonists present a more immediate question because semaglutide, liraglutide and tirzepatide are already used for weight reduction and can lower blood pressure in people with obesity. GLP-1 receptors occur in autonomic regions of the hypothalamus and brainstem, including the nucleus tractus solitarius, and have been reported on astrocytes. Experimental work suggests that GLP-1 signaling may reduce reactive gliosis and neuroinflammation. Yet central GLP-1 receptor activation has also increased sympathetic activity and heart rate in some settings. Researchers therefore do not know whether the blood-pressure effects of these drugs arise only from weight loss, from direct actions in autonomic circuits, or from weight-independent changes in astrocytic glutamate transport or inflammatory signaling.

Several gaps must be addressed before astrocytes can become a practical treatment target. It is unclear whether obesity-associated metabolic stress impairs EAAT2 before sympathetic activation and hypertension develop, whether astrocyte changes precede or follow elevated blood pressure during high-fat feeding, and whether astrocytes initiate inflammation or amplify signals from microglia, neurons, endothelial cells and peripheral immune cells. Sex differences also matter: experiments in male rodents dominate the literature, while studies of mouse and human astrocytes have found that palmitic-acid responses differ between females and males in glutamate–glutamine cycling, energy metabolism, oxidative stress and antioxidant pathways. Translation is further limited by the scarcity of direct evidence from the human paraventricular nucleus, nucleus tractus solitarius or rostral ventrolateral medulla. The review concludes that longitudinal blood-pressure telemetry, sympathetic-nerve recordings, cell-specific genetics, spatial transcriptomics and multi-omics approaches are needed to establish causality and identify astrocyte subpopulations that contribute to obesity-induced hypertension.

Subject of Research: The proposed contribution of astrocyte dysfunction to obesity-associated hypertension and sympathetic nervous system activation.

Article Title: Role of astrocytes in obesity-induced hypertension

Article References: Nanayakkara, D., Negron, C. P., & Subramanian, M. (2026). Role of astrocytes in obesity-induced hypertension. Frontiers in Neuroscience, 20, 1992730. https://doi.org/10.3389/fnins.2026.1992730

Image Credits: AI Generated

DOI: 10.3389/fnins.2026.1992730

Keywords: astrocytes, obesity-induced hypertension, sympathetic nervous system, glutamate transport, EAAT2, neuroinflammation, autonomic regulation, glial reactivity, blood pressure, metabolic dysfunction, Role, obesity-induced