The cerebral vascular system stringently regulates cerebral blood flow (CBF). The components of the blood–brain barrier (BBB) protect the brain from pathogenic infections and harmful substances, efflux waste, and exchange substances; however, diseases develop in cases of blood vessel injuries and BBB dysregulation. Vascular pathology is concurrent with the mechanisms underlying aging, Alzheimer’s disease (AD), and vascular dementia (VaD), which suggests its involvement in these mechanisms. Therefore, in the present study, we reviewed the role of vascular dysfunction in aging and neurodegenerative diseases, particularly AD and VaD. During the development of the aforementioned diseases, changes occur in the cerebral blood vessel morphology and local cells, which, in turn, alter CBF, fluid dynamics, and vascular integrity. Chronic vascular inflammation and blood vessel dysregulation further exacerbate vascular dysfunction. Multitudinous pathogenic processes affect the cerebrovascular system, whose dysfunction causes cognitive impairment. Knowledge regarding the pathophysiology of vascular dysfunction in neurodegenerative diseases and the underlying molecular mechanisms may lead to the discovery of clinically relevant vascular biomarkers, which may facilitate vascular imaging for disease prevention and treatment.

Moyamoya disease (MMD) is a cerebrovascular disease that presents with vascular stenosis and a hazy network of collateral formations in angiography. However, the detailed pathogenic pathway remains unknown. Studies have indicated that in addition to variations in the of genetic factor RNF213, unusual circulating angiogenetic factors observed in patients with MMD may play a critical role in producing “Moyamoya vessels”. Circulating angiogenetic factors, such as growth factors, vascular progenitor cells, cytokines, inflammatory factors, and other circulating proteins, could promote intimal hyperplasia in vessels and excessive collateral formation with defect structures through endothelial hyperplasia, smooth muscle migration, and atypical neovascularization. This study summarizes the hypothesized pathophysiology of how these circulating factors affect MMD and the interactive modulation between them.

Studies on the neurobiological causes of anxiety disorders suggest that the GABA system in-creases synaptic concentration and enhances the affinity of GABAA (type A) receptors for ben-zo-diazepine ligands. Flumazenil antagonizes the benzodiazepine binding site of the GABA (γ-aminobutyric acid) type /benzodiazepine receptor (BZR) complex in the central nervous sys-tem (CNS). The integration of the metabolites of flumazenil by LC-tandem mass spectrometry will complete understanding of the in vivo metabolism of flumazenil and accelerate radio-pharmaceutical inspection and registration. The main goal of our study was to investigate using reversed-phase HPLC (PR-HPLC) coupled with electrospray ionization triple quadrupole tan-dem mass spectrometry (ESI-QqQ MS) for the identification of flumazenil and its metabolites in a hepatic matrix. And a carrier-free nucleophilic fluorination with automatic synthesizer for [18F]flumazenil which applied to in vivo nano-positron emission tomography (Nano-PET)/computed tomography (CT) imaging and ex vivo bio-distribution used to analyze in normal rats. The study showed that 50% of the flumazenil was bio-transformed at 60 min by the rat liver homogenate, while one metabolite (M1) was a methyl transesterification product of flumazenil. In a rat liver microsomes system, two metabolites were identified (M2 and M3) as its carboxylic acid and hydroxylated ethylester forms, respectively. [18F]flumazenil in vivo nanoPET/CT imag-ing and ex vivo bio-distribution assay also showed significant effects on GABAA receptor availa-bility in the amygdala, prefrontal cortex, cortex, and hippocampus in the rat brain, worriless about the formation of metabolites. We showed completion of the bio-transformed course of flumazenil by the hepatic system; and [18F]flumazenil can be a good ligand and serve as a PET agent for determination of GABAA/BZR complex for multiplex neurological syndromes in the clinical stage.