Higher serum PGE2 is a predicative biomarker for postoperative delirium following elective orthopedic surgery in elderly patients.

BACKGROUND: Postoperative delirium (POD), one of the most common complications following major surgery, imposes a heavy burden on patients and society. The objective of this exploratory study was to conduct a secondary analysis to identify whether there exist novel and reliable serum biomarkers for the prediction of POD. METHODS: A total of 131 adult patients (≥ 65 years) undergoing lower extremity orthopedic surgery with were enrolled in this study. Cognitive function was assessed preoperatively with Mini-Mental State Examination (MMSE). Delirium was diagnosed according to the Confusion Assessment Method (CAM) criteria on preoperative day and postoperative days 1-3. The preoperative serum levels of a panel of 16 biochemical parameters were measured by ELISA. RESULTS: Thirty-five patients developed POD, with an incidence of 26.7%. Patients in POD group were older (P = 0.001) and had lower preoperative MMSE scores (P = 0.001). Preoperative serum levels of prostaglandin E2 (PGE2, P < 0.001), S100ß (P < 0.001), glial fibrillary acidic protein (P < 0.001) and neurofilament light (P = 0.002) in POD group were significantly increased. Logistic regression analysis showed that advanced age (OR = 1.144, 95%CI: 1.008 ~ 1.298, P = 0.037), higher serum neurofilament light (OR = 1.003, 95%CI: 1.000 ~ 1.005, P = 0.036) and PGE2 (OR = 1.031, 95%CI: 1.018 ~ 1.044, P < 0.001) levels were associated with the development of POD. In addition, serum level of PGE2 yielded an area under the ROC curve (AUC) of 0.897 to predict POD (P < 0.001), with a sensitivity of 80% and a specificity of 83.3%. CONCLUSIONS: Our study showed that higher preoperative serum PGE2 level might be a biomarker to predict the occurrence of POD in elderly patients undergoing elective orthopedic surgery. TRIAL REGISTRATION: NCT03792373 www. CLINICALTRIALS: gov .

IL-17A drives cognitive aging probably via inducing neuroinflammation and theta oscillation disruption in the hippocampus.

Cognitive aging is a major risk factor for neurodegenerative diseases and has a great impact on the living quality of older individuals. However, the precise mechanisms underlying cognitive aging remain elusive. Accumulating evidence has demonstrated that interleukin 17A (IL-17A) is responsible for cognitive decline in the process of various neurological diseases. Thus, we conducted this study aiming to investigate the role of IL-17A in cognitive aging. In the present study, 31 aging (65-85 years) and 25 young (18-35 years) patients scheduled for elective removal of internal fixation surgery with spinal anesthesia were included for measurements of preoperative cognitive function, serum and cerebrospinal fluid (CSF) levels of IL-17A. For animal study, RNAseq and Kyoto Encyclopedia of Genes and Genomes pathways were used to identify differentially expressed genes between young and aging mice. For the treatment groups, young (2-3 months) and aging (16-18 months) mice received intraperitoneally with IL-17A and anti-IL-17A antibody, respectively. Twenty-four hours later, neurocognitive behavioral tests were conducted. Our results suggested that differentially expressed genes between young and aging mice were mainly enriched in IL-17 pathways. Serum and CSF levels of IL-17A increased significantly in aging patients and were negatively correlated with mini-mental state examination scores. Both young mice receiving IL-17A and aging mice showed impaired memory, increased blood-brain barrier permeability, overactivated microglia and increased inflammatory mediators in the hippocampus. Additionally, aging mice showed a significantly decreased θ power in the task-related neural oscillations. Notably, intraperitoneal injection of anti-IL-17A antibody alleviated increased blood-brain barrier permeability, microglial activation, neuroinflammation, θ oscillation disruption and cognitive decline of aging mice. In conclusion, our study demonstrated that IL-17A may be an initiating factor of cognitive aging.

Short- and Long-Term Protective Effects of Melatonin in a Mouse Model of Sepsis-Associated Encephalopathy.

Brain dysfunction is a common complication after sepsis and is an independent risk factor for a poor prognosis, which is partly attributed to the dysregulated inflammatory response and oxidative damage. Melatonin regulates the sleep-wake cycle and also has potent anti-inflammatory and antioxidant properties, yet the protective effects of melatonin on sepsis-induced neurobehavioral dysfunction remain to be elucidated. In the present study, melatonin was administered intraperitoneally daily at a dose of 10 mg/kg for three consecutive days immediately (early treatment) or 7 days (delayed treatment) after sham operation or cecal ligation and puncture (CLP), followed by an additional treatment in drinking water until the end of behavioral tests. The concentrations of pro-inflammatory cytokines (tumor necrosis factor (TNF-α), interleukin-1ß (IL-1ß), IL-6, IL-10), malondialdehyde (MDA), superoxide dismutase (SOD), reactive oxygen species (ROS), brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF) were determined at the indicated time points. Compared with the CLP + vehicle group, we found that early melatonin treatment resulted in increased survival rate but not improvement in measures of neurobehavioral outcomes, which was accompanied by significantly lower plasma level of IL-1ß. Intriguingly, delayed melatonin treatment improved neurobehavioral dysfunction by normalization of hippocampal BDNF and GDNF expressions. In conclusion, our study suggests the beneficial effects of both early and delayed melatonin treatment after sepsis development, which implicates melatonin has a potential therapeutic value in sepsis-associated organ damage including brain dysfunction.