Differential relationships of NMDAR hypofunction and oxidative stress with cognitive decline

Serum dysregulation of serine and glycine metabolism as predictive biomarker for cognitive decline in frail elderly subjects

Frailty is a common age-related clinical syndrome characterized by a decline in the function of multiple organ systems, increased vulnerability to stressors, and a huge socio-economic burden. Despite recent research efforts, the physiopathological mechanisms underlying frailty remain elusive and biomarkers able to predate its occurrence in the early stages are still lacking. Beyond its physical component, cognitive decline represents a critical domain of frailty associated with higher risk of adverse health outcomes. We measured by High-Performance Liquid Chromatography (HPLC) a pool of serum amino acids including L-glutamate, L-aspartate, glycine, and D-serine, as well as their precursors L-glutamine, L-asparagine, and L-serine in a cohort of elderly subjects encompassing the entire continuum from fitness to frailty. These amino acids are known to orchestrate excitatory and inhibitory neurotransmission, and in turn, to play a key role as intermediates of energy homeostasis and in liver, kidney, muscle, and immune system metabolism. To comprehensively assess frailty, we employed both the Edmonton Frail Scale (EFS), as a practical tool to capture the multidimensionality of frailty, and the frailty phenotype, as a measure of physical function. We found that D-serine and D-/Total serine ratio were independent predictors of EFS but not of physical frailty. Furthermore, higher levels of glycine, glycine/L-serine and D-/Total serine were associated with worse cognition and depressive symptoms in the frail group. These findings suggest that changes in peripheral glycine and serine enantiomers homeostasis may represent a novel biochemical correlate of frailty.

Serum proteomics study on cognitive impairment after cardiac valve replacement surgery: a prospective observational study

Objective

The incidence of perioperative neurocognitive disorders (PND) is high, especially after cardiac surgeries, and the underlying mechanisms remain elusive. Here, we conducted a prospective observational study to observe serum proteomics differences in PND patients after cardiac valve replacement surgery.

Methods

Two hundred and twenty-six patients who underwent cardiac valve surgery were included. They were categorized based on scoring into non-PND group (group non-P) and PND group (group P'). The risk factors associated with PND were analyzed. These patients were further divided into group C and group P by propensity score matching (PSM) to investigate the serum proteome related to the PND by serum proteomics.

Results

The postoperative 6-week incidence of PND was 16.8%. Risk factors for PND include age, chronic illness, sufentanil dosage, and time of cardiopulmonary bypass (CPB). Proteomics identified 31 down-regulated proteins and six up-regulated proteins. Finally, GSTO1, IDH1, CAT, and PFN1 were found to be associated with PND.

Conclusion

The occurrence of PND can impact some oxidative stress proteins. This study provided data for future studies about PND to general anaesthesia and surgeries.

Neural EGFL-like 1, a craniosynostosis-related osteochondrogenic molecule, strikingly associates with neurodevelopmental pathologies

Various craniofacial syndromes cause skeletal malformations and are accompanied by neurological abnormalities at different levels, leading to tremendous biomedical, financial, social, and psychological burdens. Accumulating evidence highlights the importance of identifying and characterizing the genetic basis that synchronously modulates musculoskeletal and neurobehavioral development and function. Particularly, previous studies from different groups have suggested that neural EGFL-like-1 (Nell-1), a well-established osteochondrogenic inducer whose biopotency was initially identified in the craniofacial tissues, may also play a vital role in the central nervous system, particularly regarding neurological disorder pathologies. To provide first-hand behavior evidence if Nell-1 also has a role in central nervous system abnormalities, we compared the Nell-1-haploinsufficient (Nell-1+/6R) mice with their wild-type counterparts regarding their repetitive, social communication, anxiety-related, locomotor, sensory processing-related, motor coordination, and Pavlovian learning and memory behaviors, as well as their hippocampus transcriptional profile. Interestingly, Nell-1+/6R mice demonstrated core autism spectrum disorder-like deficits, which could be corrected by Risperidone, an FDA-approved anti-autism, anti-bipolar medicine. Besides, transcriptomic analyses identified 269 differential expressed genes, as well as significantly shifted alternative splicing of ubiquitin B pseudogene Gm1821, in the Nell-1+/6R mouse hippocampus, which confirmed that Nell-1 plays a role in neurodevelopment. Therefore, the current study verifies that Nell-1 regulates neurological development and function for the first time. Moreover, this study opens new avenues for understanding and treating craniofacial patients suffering from skeletal deformities and behavior, memory, and cognition difficulties by uncovering a novel bone-brain-crosstalk network. Furthermore, the transcriptomic analysis provides the first insight into deciphering the mechanism of Nell-1 in neurodevelopment.

Adjunctive transcranial direct current stimulation (tDCS) plus sodium benzoate for the treatment of early-phase Alzheimer's disease: A randomized, double-blind, placebo-controlled trial

Previous studies found that an NMDA receptor (NMDAR) enhancer, sodium benzoate, improved cognitive function of patients with early-phase Alzheimer's disease (AD). Transcranial direct current stimulation (tDCS) induces NMDAR-dependent synaptic plasticity and strengthens cognitive function of AD patients. This study aimed to evaluate efficacy and safety of tDCS plus benzoate in early-phase dementia. In this 24-week randomized, double-blind, placebo-controlled trial, 97 patients with early-phase AD received 10-session tDCS during the first 2 weeks. They then took benzoate or placebo for 24 weeks. We assessed the patients using Alzheimer's disease assessment scale - cognitive subscale (ADAS-cog), Clinician's Interview-Based Impression of Change plus Caregiver Input, Mini Mental Status Examination, Alzheimer's disease Cooperative Study scale for ADL in MCI, and a battery of additional cognitive tests. Forty-seven patients received sodium benzoate, and the other 50 placebo. The two treatment groups didn't differ significantly in ADAS-cog or other measures. Addition of benzoate to tDCS didn't get extra benefit or side effect in this study. For more thoroughly studying the potential of combining tDCS with benzoate in the AD treatment, future research should use other study designs, such as longer-term benzoate treatment, adding benzoate in the middle of tDCS trial sessions, or administering benzoate then tDCS.