Brain microenvironment (BME)

The brain microenvironment (BME) is a highly specialized and complex ecosystem within the central nervous system, comprising diverse cell types such as neurons, astrocytes, microglia, oligodendrocytes, and endothelial cells, along with the extracellular matrix (ECM) and interstitial fluid (ISF). It is characterized by the presence of the blood-brain barrier (BBB), which strictly regulates the transport of molecules to maintain neural homeostasis and protect the brain from toxins and pathogens (Quail & Joyce, 2017, Nature Medicine). In pathological conditions, the BME undergoes significant remodeling; for instance, in brain tumors, it is co-opted to create a supportive niche that promotes malignancy, immunosuppression, and resistance to conventional therapies (Bunt & Quail, 2023, Nature Reviews Cancer). Similarly, in neurodegenerative diseases like Alzheimer's, chronic neuroinflammation and ECM alterations within the BME contribute to synaptic loss and neuronal death. Because it is a systemic environment rather than a single molecule, it is considered a 'therapeutic landscape' where multiple components—such as cytokines, growth factors, and immune cells—are targeted simultaneously to achieve clinical efficacy.

Other names

Central nervous system microenvironmentNeural microenvironmentNeurovascular unitBrain tumor microenvironmentCNS niche

Therapeutic strategies targeting the brain microenvironment involve the modulation of neuroinflammation, inhibition of pro-angiogenic signaling (e.g., VEGF), alteration of the extracellular matrix to improve drug delivery, and the reprogramming of immune cells such as microglia and tumor-associated macrophages to restore anti-tumor or neuroprotective activity.