根據一項最近發表於《Oncotarget》期刊的新研究,瑞典卡羅林斯卡學院(Karolinska Institutet)研究人員在2型糖尿病大鼠模型中識別出特定神經細胞中的改變。由於這些神經細胞對氣味識別很重要,因此新的發現或許可以解釋為什麼2型糖尿病患者經常出現嗅覺問題,同時可能開啟新的研究領域,為對抗2型糖尿病患者中的神經退行性疾病開發預防性療法。
眾所周知的是,2型糖尿病患者經常遭受神經退行性疾病比如阿爾茨海默病的侵襲。這些神經退行性疾病的一個早期症狀是氣味識別能力的下降。這種嗅覺問題也經常出現在2型糖尿病患者中,暗示嗅覺下降可能與神經退行性疾病的發展相關聯。然而,截至目前,2型糖尿病中負責這些嗅覺問題的神經細胞一直沒有被充分認識。
在新的研究中,卡羅林斯卡學院的研究人員在2型糖尿病大鼠的梨狀皮層中識別出中間神經元中的改變。梨狀皮層是大腦的一個區域,在氣味的識別和編碼中扮演著至關重要的角色。研究人員還表明,所識別的神經改變可以被臨床使用的抗糖尿病藥物胰升血糖素樣肽1(glucagon-like peptide 1)在藥理學上抵消。
"在2型糖尿病人群中,神經退行性疾病的發病率較高"該研究作者之一Grazyna Lietzau說,"我們認為,這些發現對於開發預防性藥物療法來對抗這些患者中的阿爾茨海默病和帕金森病可能是重要的。"(生物谷Bioon.com)
DOI: 10.18632/oncotarget.6823
Type 2 diabetes-induced neuronal pathology in the piriform cortex of the rat is reversed by the GLP-1 receptor agonist Exendin-4
Type 2 diabetes (T2D) patients often present olfactory dysfunction. However, the histopathological basis behind this has not been previously shown. Since the piriform cortex plays a crucial role in olfaction, we hypothesize that pathological changes in this brain area can occur in T2D patients along aging. Thus, we determined potential neuropathology in the piriform cortex of T2D rats, along aging. Furthermore, we determined the potential therapeutic role of the glucagon-like peptide-1 receptor (GLP1-R) agonist exendin-4 to counteract the identified T2D-induced neuropathology.
Young-adult and middle-aged T2D Goto-Kakizaki rats were compared to age-matched Wistars. Additional Goto-Kakizaki rats were treated for six weeks with exendin-4/vehicle before sacrifice. Potential T2D-induced neuropathology was assessed by quantifying NeuN-positive neurons and Calbindin-D28k-positive interneurons by immunohistochemistry and stereology methods. We also quantitatively measured Calbindin-D28k neuronal morphology and JNK phosphorylation-mediated cellular stress. PI3K/AKT signalling was assessed by immunohistochemistry, and potential apoptosis by TUNEL.
We show T2D-induced neuronal pathology in the piriform cortex along aging, characterized by atypical nuclear NeuN staining and increased JNK phosphorylation, without apoptosis. We also demonstrate the specific vulnerability of Calbindin-D28k interneurons. Finally, chronic treatment with exendin-4 substantially reversed the identified neuronal pathology in correlation with decreased JNK and increased AKT phosphorylation.
Our results reveal the histopathological basis to explain T2D olfactory dysfunction. We also show that the identified T2D-neuropathology can be counteracted by GLP-1R activation supporting recent research promoting the use of GLP-1R agonists against brain diseases. Whether the identified neuropathology could represent an early hallmark of cognitive decline in T2D remains to be determined.