Reduced plasma BDNF concentration and cognitive decline in veterans with PTSD

Effects of altered neurotransmitter Glu and GABA on post-traumatic stress disorder in rats

OBJECTIVE

Investigate the role of changes in glutamic acid (Glu), gamma-aminobutyric acid (GABA), and imbalances in Glu-to-GABA ratio (GGR) in the pathogenesis of post-traumatic stress disorder (PTSD).

METHODS

Male Sprague-Dawley rats were randomly assigned to four groups: control, PTSD, PTSD+monosodium glutamate (MSG), and PTSD+lamotrigine (LTG). The PTSD model was established using the single prolonged stress (SPS) method. Rats in the PTSD+MSG and PTSD+LTG groups received MSG and LTG via gavage, respectively. At weeks 1, 2, and 4 after successful PTSD modeling, the Morris water maze (MWM) test and open field test (OFT) were conducted. Concurrently, serum concentrations of corticosterone (CORT), epinephrine, brain-derived neurotrophic factor (BDNF), Glu, and GABA were measured. Moreover, the changes of Glu, GABA and Calcium/calmodulin-dependent protein kinase II (CAMK II) in the hippocampus were also determined.

RESULTS

In the PTSD+MSG group, the GGR in both serum and hippocampus was elevated, whereas in the PTSD+LTG group, it was decreased. In the PTSD+LTG group, the content of CAMK II in the hippocampal tissue of rats was significantly increased (p < 0.01), while serum CORT and BDNF levels were reduced (p < 0.05). The change of GGR can affect the learning and spatial memory abilities, the level of spontaneous activity and the blood biochemical indexes of rats with PTSD.

CONCLUSION

Significant alterations in the GGR reflect neurotransmitter imbalances, which can influence the pathophysiology of PTSD. Targeted neurotransmitter supplementation or antagonistic therapies may help alleviate PTSD symptoms.

Assessing Causality Between Plasma Brain-Derived Neurotrophic Factor With Major Depression Disorder: A Bidirectional Mendelian Randomization Study

PURPOSE

This study employed a two-sample Mendelian randomization (MR) approach to investigate the bidirectional relationship between brain-derived neurotrophic factor (BDNF) and major depressive disorder (MDD), addressing gaps left by prior observational studies.

METHODS

We utilized Genome-Wide Association Study (GWAS) datasets, including MDD information from the Psychiatric Genomics Consortium (PGC) and the UK Biobank (N = 500,199), along with plasma BDNF measurements from the FinnGen Consortium (N = 619). In a subsequent phase, we analyzed MDD data from FinnGen (N = 448,069) with plasma BDNF data from three additional GWAS sources: UK Biobank (N = 33,924), deCODE (N = 35,353), and INTERVAL (N = 3301). Multiple MR methods were applied to ensure a robust analysis.

RESULTS

The inverse variance weighted (IVW) method revealed no significant association between plasma BDNF levels and the risk of developing MDD (IVW odds ratio [OR] = 1.00, 95% confidence interval [CI] = 0.99-1.01, p = 0.769). Similarly, no causal effect of the BDNF gene on MDD was identified (OR = 0.91, CI = 0.23-3.56, p = 0.893). Furthermore, there was no evidence supporting a causal link between MDD and plasma BDNF levels (OR = 0.99, CI = 0.89-1.09, p = 0.783). The second phase of analysis confirmed the absence of bidirectional causal relationships.

CONCLUSION

This bidirectional MR analysis provides no evidence of a causal association between plasma BDNF levels and MDD. These findings prompt a re-evaluation of plasma BDNF as a biomarker for MDD and emphasize the need for further investigation into its functional role within the plasma as well as its levels and activity in the brain and cerebrospinal fluid.

Circulating biomarkers and neuroanatomical brain structures differ in older adults with and without post-traumatic stress disorder

The aim of this study was to advance post-traumatic stress disorder (PTSD) understanding in older adults (48-77 years) by determining if circulating cytokines (IL-1β, IL-2, IL-4, IL-6, IL-12p70, IL17A and TNFα), brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF-A) and neuroanatomical brain volumes (grey and white matter, hippocampus, and amygdala) significantly differed in those with versus without PTSD. While none of the tested cytokines showed a significant difference, serum BDNF and VEGF-A levels were found to be significantly higher in the PTSD cohort. The assay used for BDNF quantification was important, with differences in general BDNF detected, but not when pro- and mature BDNF were measured specifically. Additionally, BDNF genotyping revealed a significant difference in Val66Met genotype distribution by PTSD diagnosis, with Val66Met carriers generally having lower circulating levels of BDNF compared to their Val66Val counterparts, regardless of PTSD diagnosis. Neuroanatomically, an all-female subset was examined to find total grey and white matter volumes and left and right hippocampal volumes were significantly smaller in those with PTSD. Collectively, these results show that both novel (VEGF-A) and established targets (BDNF and neuroimaging) may serve as useful biomarkers for older adults with PTSD.

Effects of Quetiapine on Novelty-Related Object Recognition Memory and Hippocampal BDNF Level in Sleep-Deprived Rats

BACKGROUND

The underlying mechanism of quetiapine (QET) in treating cognitive impairment in sleep deprivation is unclear. The present study aimed to evaluate the effects of treatment with QET on novel object recognition and hippocampal (hippo) brain-derived neurotrophic factor (BDNF) levels in rats submitted to 72 h sleep deprivation (SD).

MATERIALS AND METHODS

A total of 42 adult male Wistar albino rats were assigned into six experimental groups: non-sleep-deprived (NSD) control, short-term control group (n = 7) received a single intraperitoneal (i.p.) injection 10 mg/kg QET of 1 mL saline (4 days) (NSD-STQET), long-term control group (n = 7) received single i.p. injection 10 mg/kg QET of 1 mL saline (30 days) (NSD-LTQET); 72 h sleep-deprived (SD) group, 72 h SD short-term group received short-term i.p. injection 10 mg/kg QET of either (n = 7) (SD-STQET), and 72 h SD long-term group received long-term i.p. injection 10 mg/kg QET of either (n = 7) QET (SD-LTQET). SD was performed using the modified multiple-platform technique in a water tank for 72 h. Additionally, we aim to reveal the consequences of 72 h SD and QET effects on memory processes with hippo BDNF levels by testing rats in the novel object recognition (NOR) test and ELISA method.

RESULTS

Long-term QET administration in healthy rats decreased NOR and BDNF protein expression in the hippocampus, as did 72 h SD. Long- and short-term QET administration reversed SD effects, but only short-term QET administration increased hippo BDNF.

CONCLUSION

These results suggest that the beneficial effects of QET on SD may be partly related to the upregulation of recognition memory and neuroprotective proteins such as BDNF. However, long-term QET treatment in the absence of a disease model may have the potential to negatively impact recognition memory and BDNF levels, which support synaptic plasticity and cognitive function.

Cannabidiol Modulates Neuroinflammatory Markers in a PTSD Model Conducted on Female Rats

Post-traumatic stress disorder (PTSD) is a debilitating neuropsychiatric condition closely linked to neuroinflammation, with a higher prevalence in women. Cannabidiol (CBD), a non-psychoactive cannabinoid, has shown promise as a potential treatment for PTSD. In this study, we used a PTSD model in which female rats were subjected to a severe foot shock followed by contextual situational reminders (SRs). Testing was conducted one month after exposure. The rats received daily CBD injections for three weeks during the SRs, from days 7 to 28. Two days after the final SR, the rats underwent five extinction trials, followed by the forced swim test (FST). After a five-day rest period, the rats were sacrificed, and brain tissues from the medial prefrontal cortex (mPFC) and ventral subiculum (vSUB) were analyzed for inflammatory markers. Chronic CBD treatment reversed impairments in fear extinction caused by shock and SR. It also reduced learned helplessness in the FST and decreased the upregulation of mPFC-il1β induced by shock and SRs. Additionally, exposure to shock and SRs downregulated mPFC-il6 while upregulating vSUB-il6. CBD treatment further downregulated il6 expression in the vSUB compared to the vehicle groups. Our findings show that CBD effectively inhibited the development of PTSD-like behaviors and suppressed neuroinflammation in the mPFC.

Association between reduced plasma BDNF concentration and MMSE scores in both chronic schizophrenia and mild cognitive impairment

Reduced brain derived neurotrophic factor (BDNF) concentration is reported to be associated with a cognitive decline in schizophrenia, depending on the stage of the disease. Aim of the study was to examine the possible association between plasma BDNF and cognitive decline in chronic stable schizophrenia and mild cognitive impairment (MCI). The study included 123 inpatients of both sexes with schizophrenia, 123 patients with MCI and 208 healthy control subjects. Cognitive abilities were assessed using mini mental state examination (MMSE), Clock Drawing test (CDT) and cognitive subscale of the Positive and Negative Syndrome Scale (PANSS). Plasma BDNF concentration was determined using ELISA. BDNF concentration was lower in patients with schizophrenia and MCI compared to age-matched healthy controls and was similar in carriers of different BDNF Val/66Met genotypes. The MMSE and CDT scores were lower in patients with schizophrenia compared to healthy controls and subjects with MCI. Reduced plasma BDNF was significantly associated with lower MMSE scores in all subjects. BDNF concentration in patients with schizophrenia was not affected by clinical and demographic factors. BDNF Val66Met polymorphism was not associated with the MMSE scores in all participants. Further studies should include longitudinal follow-up and other cognitive scales to confirm these results and offer cognition-improving strategies to prevent cognitive decline in chronic schizophrenia.

Brain-derived neurotrophic factor levels across psychiatric disorders: A systemic review and network meta-analysis

As an important neurotrophic factor in the central nervous system, Brain-derived Neurotrophic Factor (BDNF) has been implicated in the pathophysiology of psychiatric disorders in many studies. However, its value as a biomarker for the diagnosis and differential diagnosis of mental disorders is still controversial, and its change patterns among different mental disorders have not been compared. We conducted a network meta-analysis of BDNF levels in different psychiatric disorders including schizophrenia(SCZ), major depressive disorder(MDD), bipolar disorder(BD), panic disorder(PD), post-traumatic stress disorder(PTSD), obsessive-compulsive disorder(OCD), generalized anxiety disorder(GAD) and insomnia. Studies were identified by searching electronic databases through 31/05/2023. BDNF levels decreased in patients with BD, MDD, OCD, PD, SCZ compared with controls, while significantly increased in patients with PTSD. According to the network meta-analysis, BDNF levels were significantly decreased in MDD and SCZ compared with BD (-2.6, 95% CIs [-5.32 to -0.15] and - 2.68 95% CIs [-5.18 to -0.23] respectively). However, in the traditional meta-analysis, there was a trend towards lower BDNF levels in SCZ compared to BD, with no significant difference (SMD = -0.20, 95% CIs [-0.49 to 0.08]). In conclusion, abnormal BDNF levels have been found in psychiatric disorders, and the changes in peripheral BDNF levels in patients with psychiatric disorders were reconfirmed in this study, which suggests BDNF exhibits promising clinical utility and may hold diagnostic value in distinguishing between MDD and BD.

Biomarkers associated with cognitive impairment in post-traumatic stress disorder: A systematic review of current evidence

OBJECTIVE

This systematic review aimed at synthesizing current evidence on biomarkers associated with cognitive impairment (CI) in Post-Traumatic Stress Disorder (PTSD).

METHODS

A systematic literature search was conducted for studies assessing biomarkers associated with CI in PTSD.

RESULTS

Of the 10,149 titles screened, 8 studies met our inclusion criteria. In a single longitudinal study, MRI volumes, Aβ and tau accumulation were not associated with CI in PTSD. Studies on structural imaging reported no significant association between morphological changes and CI. Two studies on diffusion neuroimaging showed abnormalities in white matter tracts which were cross-sectionally associated with CI in PTSD. Similarly, lower resting-state functional connectivity in neocortical networks, and elevated tau in the neocortex were also cross sectionally associated with CI. Two single studies on biochemical biomarkers showed that sixteen novel plasma proteins and lower BDNF, indicative of genetic vulnerabilities associated with neural and synaptic dysfunctions commonly observed in neurodegeneration, were cross-sectionally associated with CI in PTSD. Overall, evidence is of low quality.

CONCLUSIONS

Longitudinal research utilizing large representative samples of trauma exposed populations are needed to establish the utility of specific biomarkers in monitoring cognitive decline in PTSD.

Ketamine alleviates fear memory and spatial cognition deficits in a PTSD rat model via the BDNF signaling pathway of the hippocampus and amygdala

BACKGROUND

Post-traumatic stress disorder (PTSD) is associated with traumatic stress experiences. This condition can be accompanied by learning and cognitive deficits. Studies have demonstrated that ketamine can rapidly and significantly alleviate symptoms in patients with chronic PTSD. Nonetheless, the effects of ketamine on neurocognitive impairment and its mechanism of action in PTSD remain unclear.

METHODS

In this study, different concentrations of ketamine (5, 10, 15, and 20 mg/kg, i.p.) were evaluated in rat models of single prolonged stress and electrophonic shock (SPS&S). Expression levels of brain-derived neurotrophic factor (BDNF) and post-synaptic density-95 (PSD-95) in the hippocampus (HIP) and amygdala (AMG) were determined by Western blot analysis and immunohistochemistry.

RESULTS

The data showed that rats subjected to SPS&S exhibited significant PTSD-like cognitive impairment. The effect of ketamine on SPS&S-induced neurocognitive function showed a U-shaped dose effect in rats. A single administration of ketamine at a dosage of 10-15 mg/kg resulted in significant changes in behavioral outcomes. These manifestations of improvement in cognitive function and molecular changes were reversed at high doses (15-20 mg/kg).

CONCLUSION

Overall, ketamine reversed SPS&S-induced fear and spatial memory impairment and the down-regulation of BDNF and BDNF-related PSD-95 signaling in the HIP and AMG. A dose equal to 15 mg/kg rapidly reversed the behavioral and molecular changes and promoted the amelioration of cognitive dysfunction. The enhanced association of BDNF signaling with PSD-95 effects could be involved in the therapeutic efficiency of ketamine for PTSD.

Epigenetic Alterations in Post-Traumatic Stress Disorder: Comprehensive Review of Molecular Markers

Background

Post-traumatic stress disorder (PTSD) can occur after a traumatic event. PTSD is characterized by nightmares, flashbacks and avoidance of stressors. It currently affects 2-8% of the population, with military personnel particularly susceptible. Studies show that environmental stressors can induce various epigenetic changes that shape the PTSD phenotype. Despite the significant impact of epigenetic factors on PTSD symptoms and susceptibility, they have not been widely discussed in the literature. This review focuses on describing epigenetic mechanisms in PTSD, especially DNA methylation, chromatin regulation, and noncoding RNA.

Summary

The article includes relevant studies published from 2013 to 2023, excluding non-English-language studies or studies with insufficient data. This review investigated gene methylation changes in association with PTSD, including those related to the hypothalamic-pituitary-adrenal axis, brain-derived neurotrophic factor, neurotransmitters, and immune system functioning, as well as the role of histones and regulatory noncoding RNAs.

Key Messages

Epigenetic alterations play a crucial role in shaping PTSD susceptibility, symptomatology, and long-term outcomes, highlighting their potential as important markers and therapeutic targets. Understanding these alterations can aid in developing clinical strategies to better predict, prevent, and treat PTSD. However, further large-scale longitudinal studies are needed to establish the temporal relationship between epigenetic changes and the onset of PTSD, as well as to classify other potential epigenetic mechanisms.

[Cognitive impairment in post-traumatic stress disorder]

Post-traumatic stress disorder (PTSD) is a common mental health disorder, with an incidence of up to 12.5% among primary care patients. Most often, PTSD is detected in combat veterans, victims of terrorist attacks and terror, but it can also be a consequence of traumatic brain injury and medical interventions. Impaired cognitive functioning is a key feature of PTSD, including attention deficits and reduced processing speed, executive dysfunction, and impairments in verbal learning and memory. Cognitive impairments in PTSD are significantly persistent and are largely similar in nature to neuropsychological impairments in neurodegenerative pathology. Possible pathogenetic mechanisms underlying PTSD are the development of neuroinflammation, oxidative stress and decreased production of neurotrophic factors. One of the promising areas of treatment is the use of Cerebrolysin, which has powerful neurotrophic and anti-inflammatory activity.

Clinical Efficacy and Mechanistic Insights of Anshen Dingzhi Prescription on Breast Cancer-Related PTSD Through Network Pharmacology and Molecular Docking

Anshen Dingzhi prescription (ADP) is a classic prescription of traditional Chinese medicine, which has been used in the treatment of neuropsychiatric diseases. However, its treatment of breast cancer-related post-traumatic stress disorder (BC-PTSD) lacks clinical research evidence and its mechanism is not clear. The present study investigated the efficacy and action mechanism of ADP against BC-PTSD. The results of the clinical trial showed that after 4 weeks of treatment, both groups showed reduced post-traumatic stress disorder checklist-civilian version (PCL-C), Pittsburgh sleep quality index (PSQI), self-rating depression scale (SDS) and self-rating anxiety scale (SAS) scores, and increased functional assessment of cancer therapy-breast (FACT-B) scores. The serum cortisol (CORT), tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) levels were decreased and brain-derived neurotrophic factor (BDNF) level were increased, and the improvement of serum TNF-α, IL-1β, and BDNF in treatment group was better than that of the control group. The overall treatment efficacy in the treatment group (43.90%) was superior to that in the control group (23.81%), and the overall incidence of adverse effects was lower than that in the control group. The results of network analysis and molecular docking showed that ADP blood components could act on IL1B, TNF, and BDNF. ADP contributes to the treatment of BC-PTSD symptoms, with a mechanism possibly related to its regulatory effect on TNF-α, IL-1β, and BDNF levels.Trial registration: Chinese Clinical Trial Registry, http://www.chictr.org.cn,ChiCTR2300077801.

Influence of Mild Chronic Stress and Social Isolation on Acute Ozone-Induced Alterations in Stress Biomarkers and Brain-Region-Specific Gene Expression in Male Wistar-Kyoto Rats

Individuals with psychosocial stress often experience an exaggerated response to air pollutants. Ozone (O3) exposure has been associated with the activation of the neuroendocrine stress-response system. We hypothesized that preexistent mild chronic stress plus social isolation (CS), or social isolation (SI) alone, would exacerbate the acute effects of O3 exposure on the circulating adrenal-derived stress hormones, and the expression of the genes regulating glucocorticoid stress signaling via an altered stress adaptation in a brain-region-specific manner. Male Wistar-Kyoto rats (5 weeks old) were socially isolated, plus were subjected to either CS (noise, confinement, fear, uncomfortable living, hectic activity, and single housing), SI (single housing only, restricted handling and no enrichment) or no stress (NS; double housing, frequent handling and enrichment provided) for 8 weeks. The rats were then exposed to either air or O3 (0.8 ppm for 4 h), and the samples were collected immediately after. The indicators of sympathetic and hypothalamic-pituitary axis (HPA) activation (i.e., epinephrine, corticosterone, and lymphopenia) increased with O3 exposure, but there were no effects from CS or SI, except for the depletion of serum BDNF. CS and SI revealed small changes in brain-region-specific glucocorticoid-signaling-associated markers of gene expression in the air-exposed rats (hypothalamic Nr3c1, Nr3c2 Hsp90aa1, Hspa4 and Cnr1 inhibition in SI; hippocampal HSP90aa1 increase in SI; and inhibition of the bed nucleus of the stria terminalis (BNST) Cnr1 in CS). Gene expression across all brain regions was altered by O3, reflective of glucocorticoid signaling effects, such as Fkbp5 in NS, CS and SI. The SI effects on Fkbp5 were greatest for SI in BNST. O3 increased Cnr2 expression in the hypothalamus and olfactory bulbs of the NS and SI groups. O3, in all stress conditions, generally inhibited the expression of Nr3c1 in all brain regions, Nr3c2 in the hippocampus and hypothalamus and Bdnf in the hippocampus. SI, in general, showed slightly greater O3-induced changes when compared to NS and CS. Serum metabolomics revealed increased sphingomyelins in the air-exposed SI and O3-exposed NS, with underlying SI dampening some of the O3-induced changes. These results suggest a potential link between preexistent SI and acute O3-induced increases in the circulating adrenal-derived stress hormones and brain-region-specific gene expression changes in glucocorticoid signaling, which may partly underlie the stress dynamic in those with long-term SI.

Neuroprotective and Disease-Modifying Effects of the Triazinetrione ACD856, a Positive Allosteric Modulator of Trk-Receptors for the Treatment of Cognitive Dysfunction in Alzheimer's Disease

The introduction of anti-amyloid monoclonal antibodies against Alzheimer's disease (AD) is of high importance. However, even though treated patients show very little amyloid pathology, there is only a modest effect on the rate of cognitive decline. Although this effect can possibly increase over time, there is still a need for alternative treatments that will improve cognitive function in patients with AD. Therefore, the purpose of this study was to characterize the triazinetrione ACD856, a novel pan-Trk positive allosteric modulator, in multiple models to address its neuroprotective and potential disease-modifying effects. The pharmacological effect of ACD856 was tested in recombinant cell lines, primary cortical neurons, or animals. We demonstrate that ACD856 enhanced NGF-induced neurite outgrowth, increased the levels of the pre-synaptic protein SNAP25 in PC12 cells, and increased the degree of phosphorylated TrkB in SH-SY5Y cells. In primary cortical neurons, ACD856 led to increased levels of phospho-ERK1/2, showed a neuroprotective effect against amyloid-beta or energy-deprivation-induced neurotoxicity, and increased the levels of brain-derived neurotrophic factor (BDNF). Consequently, administration of ACD856 resulted in a significant increase in BDNF in the brains of 21 months old mice. Furthermore, repeated administration of ACD856 resulted in a sustained anti-depressant effect, which lasted up to seven days, suggesting effects that go beyond merely symptomatic effects. In conclusion, the results confirm ACD856 as a cognitive enhancer, but more importantly, they provide substantial in vitro and in vivo evidence of neuroprotective and long-term effects that contribute to neurotrophic support and increased neuroplasticity. Presumably, the described effects of ACD856 may improve cognition, increase resilience, and promote neurorestorative processes, thereby leading to a healthier brain in patients with AD.

Recent advances in the role of miRNAs in post-traumatic stress disorder and traumatic brain injury

Post-traumatic stress disorder (PTSD) is usually considered a psychiatric disorder upon emotional trauma. However, with the rising number of conflicts and traffic accidents around the world, the incidence of PTSD has skyrocketed along with traumatic brain injury (TBI), a complex neuropathological disease due to external physical force and is also the most common concurrent disease of PTSD. Recently, the overlap between PTSD and TBI is increasingly attracting attention, as it has the potential to stimulate the emergence of novel treatments for both conditions. Of note, treatments exploiting the microRNAs (miRNAs), a well-known class of small non-coding RNAs (ncRNAs), have rapidly gained momentum in many nervous system disorders, given the miRNAs' multitudinous and key regulatory role in various biological processes, including neural development and normal functioning of the nervous system. Currently, a wealth of studies has elucidated the similarities of PTSD and TBI in pathophysiology and symptoms; however, there is a dearth of discussion with respect to miRNAs in both PTSD and TBI. In this review, we summarize the recent available studies of miRNAs in PTSD and TBI and discuss and highlight promising miRNAs therapeutics for both conditions in the future.

The Devastating Effects of Sleep Deprivation on Memory: Lessons from Rodent Models

In this narrative review article, we discuss the role of sleep deprivation (SD) in memory processing in rodent models. Numerous studies have examined the effects of SD on memory, with the majority showing that sleep disorders negatively affect memory. Currently, a consensus has not been established on which damage mechanism is the most appropriate. This critical issue in the neuroscience of sleep remains largely unknown. This review article aims to elucidate the mechanisms that underlie the damaging effects of SD on memory. It also proposes a scientific solution that might explain some findings. We have chosen to summarize literature that is both representative and comprehensive, as well as innovative in its approach. We examined the effects of SD on memory, including synaptic plasticity, neuritis, oxidative stress, and neurotransmitters. Results provide valuable insights into the mechanisms by which SD impairs memory function.

Effects and mechanisms of extremely cold environment on body response after trauma

With the outbreak of the Ukrainian crisis, extremely cold environment warfare has once again become the focus of international attention. People exposed to extremely cold environments may suffer from cold damage, further aggravate trauma, trigger high disability and mortality rates, and even cause serious sequelae. To declare the effects and mechanisms of the extremely cold environment on the body after trauma, this paper reviews, firstly, physiological reaction of human body in an extremely cold environment. Then, the post-traumatic body response in an extremely cold environment was introduced, and finally, the sequelae of trauma in extremely cold environment was further summarized in the paper. The results indicated that extremely cold environment can cause a series of damage to the body, especially the body after trauma. The extremely cold factor is a double-edged sword, showing a favorable and unfavorable side in different aspects. Moreover, in addition to the trauma suffered by the body, the subsequent sequelae such as cognitive dysfunction, anxiety, depression and even post-traumatic stress disorder may also be induced. The paper summarizes the human body's physiological response in an extremely cold environment, and declares the effects and mechanisms of the extremely cold environment on the body after trauma, which may provide a theoretical basis for effectively improving the level of combat trauma treatment in extremely cold regions.

Inhibition of mGluR5 alters BDNF/TrkB and GLT-1 expression in the prefrontal cortex and hippocampus and ameliorates PTSD-like behavior in rats

RATIONALE AND OBJECTIVE

Post-traumatic stress disorder (PTSD) is a prevalent and debilitating psychiatric disorder. However, its specific etiological mechanism remains unclear. Previous studies have shown that traumatic stress changes metabotropic glutamate receptor 5 (mGluR5) expression in the hippocampus (HIP) and prefrontal cortex (PFC). More importantly, mGluR5 expression is often accompanied by alterations in brain-derived neurotrophic factor (BDNF). Furthermore, BDNF/tropomyosin-associated kinase B (TrkB) signaling plays multiple roles, including roles in neuroplasticity and antidepressant activity, by regulating glutamate transporter-1 (GLT-1) expression. This study aims to explore the effects of inhibiting mGluR5 on PTSD-like behaviors and BDNF, TrkB, and GLT-1 expression in the HIP and PFC of inevitable foot shock (IFS)-treated rats.

METHODS

Seven-day IFS was used to establish a PTSD rat model, and 2-methyl-6-(phenylethynyl)-pyridine (MPEP) (10 mg/kg, intraperitoneal injection) was used to inhibit the activity of mGluR5 during IFS in rats. After modeling, behavioral changes and mGluR5, BDNF, TrkB, and GLT-1 expression in the PFC and HIP were examined.

RESULTS

First, the IFS procedure induced PTSD-like behavior. Second, IFS increased the expression of mGluR5 and decreased BDNF, TrkB, and GLT-1 expression in the PFC and HIP. Third, the mGluR5 antagonist blocked the above behavioral and molecular alterations.

CONCLUSIONS

mGluR5 was involved in IFS-induced PTSD-like behavior by changing BDNF, TrkB, and GLT-1 expression.

Relationship between Brain-Derived Neurotrophic Factor and Cognitive Decline in Patients with Mild Cognitive Impairment and Dementia

In the last decade, increasing evidence has emerged linking alterations in the brain-derived neurotrophic factor (BDNF) expression with the development of Alzheimer's disease (AD). Because of the important role of BDNF in cognition and its association with AD pathogenesis, the aim of this study was to evaluate the potential difference in plasma BDNF concentrations between subjects with mild cognitive impairment (MCI; N = 209) and AD patients (N = 295) and to determine the possible association between BDNF plasma levels and the degree of cognitive decline in these individuals. The results showed a significantly higher (p < 0.001) concentration of plasma BDNF in subjects with AD (1.16; 0.13-21.34) compared with individuals with MCI (0.68; 0.02-19.14). The results of the present study additionally indicated a negative correlation between cognitive functions and BDNF plasma concentrations, suggesting higher BDNF levels in subjects with more pronounced cognitive decline. The correlation analysis revealed a significant negative correlation between BDNF plasma levels and both Mini-Mental State Examination (p < 0.001) and Clock Drawing test (p < 0.001) scores. In conclusion, the results of our study point towards elevated plasma BDNF levels in AD patients compared with MCI subjects, which may be due to the body's attempt to counteract the early and middle stages of neurodegeneration.

Glutamate Neurotoxicity and Destruction of the Blood–Brain Barrier: Key Pathways for the Development of Neuropsychiatric Consequences of TBI and Their Potential Treatment Strategies

Traumatic brain injury (TBI) is associated with significant cognitive and psychiatric conditions. Neuropsychiatric symptoms can persist for years following brain injury, causing major disruptions in patients’ lives. In this review, we examine the role of glutamate as an aftereffect of TBI that contributes to the development of neuropsychiatric conditions. We hypothesize that TBI causes long-term blood–brain barrier (BBB) dysfunction lasting many years and even decades. We propose that dysfunction in the BBB is the central factor that modulates increased glutamate after TBI and ultimately leads to neurodegenerative processes and subsequent manifestation of neuropsychiatric conditions. Here, we have identified factors that determine the upper and lower levels of glutamate concentration in the brain after TBI. Furthermore, we consider treatments of disruptions to BBB integrity, including repairing the BBB and controlling excess glutamate, as potential therapeutic modalities for the treatment of acute and chronic neuropsychiatric conditions and symptoms. By specifically focusing on the BBB, we hypothesize that restoring BBB integrity will alleviate neurotoxicity and related neurological sequelae.