Department of Clinical and Behavioral Neurology (P.B., F.P., I.P., M.I., F.S., A.C., C. Chiapponi, C. Caltagirone, G.S.), IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience (C. Caltagirone), University "Tor Vergata," Rome, Italy; and Menninger Department of Psychiatry and Behavioral Sciences (G.S.), Baylor College of Medicine, Houston, TX.
Neurol Neuroimmunol Neuroinflamm. 2015 May 7;2(4):e111. doi: 10.1212/NXI.0000000000000111. eCollection 2015 Aug.
Since schizophrenia (SCZ) is often accompanied by hippocampal abnormalities and dysregulation of cytokine production, this study aimed to investigate the impact of the cytokine interleukin (IL)-18, whose biological system appears to be perturbed in SCZ, on brain structure and clinical severity in patients with chronic SCZ.
The serum levels of IL-18, including its free bioactive form (i.e., the cytokine fraction not bound to its specific endogenous inhibitor IL-18 binding protein), were evaluated in a case-control study involving 71 individuals with SCZ diagnosis and 29 healthy controls. All participants underwent brain MRI automatic evaluation for hippocampal volume estimation. The Positive and Negative Syndrome Scale (PANSS) was administered to measure severity of symptoms in patients with SCZ.
Lower amounts of free IL-18 were related to smaller hippocampal volume measures in patients with SCZ. Furthermore, in line with a possible neuroprotective effect of the cytokine, higher levels of free IL-18 corresponded to lower subscores of PANSS depression in patients with SCZ.
These findings demonstrate that the levels of circulating bioactive IL-18 are related to both hippocampal volume and severity of psychopathologic symptoms in patients with SCZ, confirming the involvement of the cytokine in SCZ pathophysiology and suggesting hippocampal-dependent and neuroprotective functions of IL-18 in this clinical context.
由于精神分裂症 (SCZ) 常伴有海马体异常和细胞因子产生失调，本研究旨在探究细胞因子白细胞介素 (IL)-18 的影响，其生物系统在 SCZ 中似乎受到干扰，对慢性 SCZ 患者的大脑结构和临床严重程度的影响。
采用病例对照研究，评估 71 名 SCZ 诊断患者和 29 名健康对照者的血清 IL-18 水平，包括其游离生物活性形式（即与特定内源性抑制剂 IL-18 结合蛋白未结合的细胞因子部分）。所有参与者均接受大脑 MRI 自动评估，以估计海马体体积。阳性和阴性综合征量表 (PANSS) 用于衡量 SCZ 患者的症状严重程度。
游离 IL-18 含量较低与 SCZ 患者的海马体体积测量值较小有关。此外，与细胞因子可能具有神经保护作用一致，SCZ 患者中游离 IL-18 水平较高与 PANSS 抑郁分量表得分较低相关。
这些发现表明，循环生物活性 IL-18 的水平与 SCZ 患者的海马体体积和精神病理症状严重程度相关，证实了细胞因子在 SCZ 发病机制中的作用，并表明在这种临床情况下，IL-18 具有海马体依赖性和神经保护功能。
