Previous studies have reported that β-amyloid peptides (Aβ) are observed in the nasal mucosa of postmortem human samples. In a mouse model of Alzheimer's disease (AD), nasal Aβ levels positively correlate with insoluble Aβ levels in the brain. However, it is difficult to measure Aβ content in human nasal smears. Here we report a novel and sensitive method of measuring Aβ42 content in the human nasal cavity and its application in normal human volunteers. We collected nasal smears by cotton swab from the mucosa of the inferior nasal concha and common nasal meatus of 26 normal volunteers with an age range of 23-78 years. The swabs were placed in microtubes and extracted with pure water. Extract solution was removed from each sample for protein assay and the remaining sample was added with formic acid, incubated at 70℃ for one hour, and then centrifuged in a centrifugal filter device to remove larger protein complexes and cellular debris. The filtrates were concentrated and then buffered before Aβ42 concentrations were measured using a commercially available ELISA kit. Samples from five volunteers were also assayed for Aβ42 content without pretreatment. Our novel method for collecting and assaying nasal mucosal smears enabled us to measure Aβ42 content in both the inferior nasal concha and the common nasal meatus of all cases examined, despite the levels being under detection limits (0.1 pmol/L) without pretreatment. There was significantly more Aβ42 content per gram of total protein in the inferior nasal concha (12.37 ± 5.98 pmol/g) than in the common nasal meatus (3.58 ± 1.94 pmol/g; P < 0.001). Thus, this method would be useful for AD screening.

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Brain-derived neurotrophic factor (BDNF) is expressed at high levels in the hippocampal dentate gyrus (DG), and decreased levels of BDNF have been implicated in the pathophysiology of schizophrenia (SCZ). We have previously reported that yokukansan (YKS), which is a traditional Japanese medicine, is effective for SCZ and promotes neurogenesis in the DG of Gunn rats, an animal model of SCZ. In this study, we investigated the effect of YKS on serum BDNF levels in Gunn rats. The results showed that YKS increased serum BDNF in this model, which may suggest that BDNF expression in the DG leads to increased neurogenesis. Our findings may help to explain the efficacy of YKS in treating SCZ.

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Radiation therapy, the most commonly used for the treatment of brain tumors, has been shown to be of major significance in tumor control and survival rate of brain tumor patients. About 200,000 patients with brain tumor are treated with either partial large field or whole brain radiation every year in China. The use of radiation therapy for treatment of brain tumors, however, may lead to devastating functional deficits in brain several months to years after treatment. An initial brain pathology resulting from exposure to radiation appears to be the dysfunction or disruption of the blood-brain barrier (BBB) and edema formation, which resulted from loss of tight junction (TJ) proteins and BBB components pericytes and astrocyte end-feet. Both of these scenarios lead to apoptosis of endothelial and neural cells and neuroinflammation in and around capillaries, which may progress into a variety of neurological impairments. It's been found that Bone-marrow-derived EPCs (endothelial progenitor cells) play an integral role in the regulation and protection of the endothelium, as well as new vessel formation. It can incorporate into injured vessels and become mature endothelial cells during re-endothelialization and neovascularization processes, so the transplantation of EPCs into ischemic tissues provide a novel therapeutic option for radiation-induced brain injury. The efficacy of EPCs repairing disrupted BBB can be evaluated from the changes of expression of S100B, VEGF and EBA. MRI is a non-invasive method that can be used to track labeled transplanted cells,which can show the exact trace of EPCs in the region of brain injury. This review discusses the therapeutic potential of EPCs for vascular ischemic diseases associated with radiation-induced brain injury.

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