The Glutamatergic System in Treatment-Resistant Depression and Comparative Effectiveness of Ketamine and Esketamine: Role of Inflammation?

Patient Experience with Intranasal Esketamine in Treatment-Resistant Depression: Insights from a Multicentric Italian Study (REAL-ESKperience)

Background. Treatment-resistant depression (TRD) is a prevalent, high-burden disorder. Esketamine nasal spray (ESK-NS) has been approved for, T.R.D.; and efficacy has been observed in both clinical trials and real-world studies. However, observations integrating patients' perspective on this treatment are limited. This multicentric Italian study explored experiences with ESK-NS in TRD patients, focusing on perceived therapeutic effects and overall satisfaction. Methods. A self-report survey was administered to 236 outpatients with TRD (55.1% females, 54.1 ± 14.1 years) treated with ESK-NS for at least three consecutive months within standard clinical care. Based on satisfaction levels, participants were classified as "unsatisfied" (10.2%), "partially satisfied" (19.1%), "satisfied" (44.4%), or "very satisfied" (26.3%), and compared for sociodemographic, clinical characteristics, and feedback on perceived benefits. Artificial intelligence (OpenAI) served to categorize responses to an open-ended question. Results. Enhanced quality of life was reported by 88.4% of participants. Significant differences emerged in earliest self-perceived benefits, most relevant effects, and impact on global functioning across groups. Specifically, "very satisfied" patients described the following: early improvements in depressed mood, suicidal thoughts, and restlessness; decreased suicidal thoughts among the most significant effects; and functional gains across all domains. OpenAI identified experiences of personal growth and rediscovery and a desire for tailored settings and approaches as recurring topics. Conclusions. Most patients reported a positive perception of ESK-NS treatment. The most satisfied participants highlighted significant benefits to depressed mood, suicidal thoughts, and overall functioning. Patient-reported experiences offer insights into different psychopathological dimensions, including functional outcomes and quality of life. Integrating these perspectives into clinical practice might assist treatment personalization, improving patients' adherence and satisfaction.

Recent Advances in the Mechanisms of Postoperative Neurocognitive Dysfunction: A Narrative Review

Postoperative neurocognitive dysfunction (PND) is a prevalent and debilitating complication in elderly surgical patients, characterized by persistent cognitive decline that negatively affects recovery and quality of life. As the aging population grows, the rising number of elderly surgical patients has made PND an urgent clinical challenge. Despite increasing research efforts, the pathophysiological mechanisms underlying PND remain inadequately characterized, underscoring the need for a more integrated framework to guide targeted interventions. To better understand the molecular mechanisms and therapeutic targets of PND, this narrative review synthesized evidence from peer-reviewed studies, identified through comprehensive searches of PubMed, Embase, Cochrane Library, and Web of Science. Key findings highlight neuroinflammation, oxidative stress, mitochondrial dysfunction, neurotransmitter imbalances, microvascular changes, and white matter lesions as central to PND pathophysiology, with particular parallels to encephalocele- and sepsis-associated cognitive impairments. Among these, neuroinflammation, mediated by pathways such as the NLRP3 inflammasome and blood-brain barrier disruption, emerges as a pivotal driver, triggering cascades that exacerbate neuronal injury. Oxidative stress and mitochondrial dysfunction synergistically amplify these effects, while neurotransmitter imbalances and microvascular alterations, including white matter lesions, contribute to synaptic dysfunction and cognitive decline. Anesthetic agents modulate these interconnected pathways, exhibiting both protective and detrimental effects. Propofol and dexmedetomidine demonstrate neuroprotective properties by suppressing neuroinflammation and microglial activation, whereas inhalational anesthetics like sevoflurane intensify oxidative stress and inflammatory responses. Ketamine, with its anti-inflammatory potential, offers promise but requires further evaluation to determine its long-term safety and efficacy. By bridging molecular insights with clinical practice, this review highlights the critical role of personalized anesthetic strategies in mitigating PND and improving cognitive recovery in elderly surgical patients. It aims to inform future research and clinical decision-making to address this multifaceted challenge.

Esketamine alleviates ferroptosis-mediated acute lung injury by modulating the HIF-1α/HO-1 pathway

BACKGROUND

Alveolar epithelial cell (AEC) ferroptosis contributes to the progression of acute lung injury (ALI). Esketamine (ESK) is a new clinical sedative, anesthetic, and analgesic drug that has attracted substantial attention in mental health research because of its antidepressant effects. However, the effects of ESK on ferroptosis-mediated ALI remain unclear.

OBJECTIVE

This study aimed to explore the protective effect of ESK on AEC ferroptosis in ALI and its potential molecular mechanism in vivo and in vitro.

METHODS

The antiferroptotic and anti-inflammatory effects of ESK were assessed in a mouse model of lipopolysaccharide (LPS)-induced ALI. In vitro, the epithelial cell lines MLE-12 and A549 were used to examine the underlying mechanism by which ESK regulates inflammation and ferroptosis.

RESULTS

ESK protected mice against LPS-induced ALI, significantly attenuated pathological changes in the lungs and decreased inflammation and ferroptosis. In vitro, ESK inhibited LPS-induced inflammation and ferroptosis in MLE-12 and A549 cells. Moreover, ferroptosis mediated inflammation in LPS-induced ALI in vivo and in vitro, and ESK decreased the LPS-induced inflammatory response by suppressing ferroptosis. ESK promoted the HIF-1α/HO-1 pathway in LPS-treated AECs and in the lung tissues of mice with LPS-induced ALI. Moreover, pretreatment with ESK and the HIF-1α stabilizer dimethyloxaloylglycine (DMOG) substantially attenuated lung injury and prevented changes in ferroptosis-related biochemical indicators, including glutathione (GSH) depletion, malondialdehyde (MDA) production and glutathione peroxidase 4 (GPX4) downregulation, in untreated LPS-induced mice but not in LPS-induced mice treated with the HO-1 inhibitor zinc protoporphyrin (ZNPP). Similar effects were observed in vitro in HO-1 siRNA-transfected A549 cells after LPS incubation but not in control siRNA-transfected cells.

CONCLUSION

ESK can inhibit ferroptosis-mediated lipid peroxidation by increasing the expression of HIF-1α/HO-1 pathway, highlighting the potential of ESK to treat LPS-induced ALI.

Exploring the Analgesic Efficacy and mechanisms of low-dose esketamine in pregnant women undergoing cesarean section: A randomized controlled trial

Background

Postoperative pain is a prevalent concern following a cesarean section. This study aimed to investigate the effect and mechanism of low-dose (0.1 mg/kg) esketamine on postoperative pain management in pregnant women undergoing cesarean sections, specifically in cases where both patient-controlled intravenous analgesia (PCIA) and patient-controlled epidural analgesia (PCEA) were employed.

Methods

Pregnant women intending to undergo elective cesarean section were divided into four subgroups based on the intravenous administration of esketamine and the specific analgesia methods employed: E1 (0.1 mg/kg esketamine + PCEA), E2 (0.1 mg/kg esketamine + PCIA), C1 (saline + PCEA), and C2 (saline + PCIA). The primary outcome was the maximum pain score within 24 h postoperatively. Secondary outcomes included the pressure pain threshold and tolerance at 30 min and 24 h postoperatively, along with the inflammation and adverse event index scores.

Results

A total of 118 pregnant women were assigned to the four groups: E1 (n = 29), E2 (n = 29), C1 (n = 30), and C2 (n = 30). Compared with those in the control groups (C1 + C2), the maximum postoperative pain scores within 24 h in the esketamine groups (E1 + E2) were significantly lower (4 [2-5] vs. 4 [4-6], P = 0.002), and the E1 group exhibited superior analgesic effects compared with other groups. No significant differences were observed in postoperative hyperalgesia or inflammation across the four groups. Notably, esketamine combined with PCIA increased the incidence of postoperative nausea and vomiting (7 [25 %] vs. 0 [0 %]; P = 0.005).

Conclusion

The administration of low-dose (0.1 mg/kg) esketamine effectively alleviates pain following cesarean section, and the analgesic effect is notably enhanced in combination with PCEA. Importantly, these effects do not appear to be mediated through anti-inflammatory mechanisms or the inhibition of hyperalgesia.

Clinical trial registration number

NCT05414006.

Antidepressant effects of esketamine via the BDNF/AKT/mTOR pathway in mice with postpartum depression and their offspring

Postpartum depression (PPD) is a serious mental health problem that can negatively affect future generations. BDNF/AKT/mTOR signaling in the frontal lobe and hippocampus in mice is associated with depression, but its role in mice with PPD and their offspring is unknown. This study was aimed at investigating the effects of esketamine (ESK), a drug approved for treatment of refractory depression, on the BDNF/AKT/mTOR pathway in mice with PPD and their offspring. A model of chronic unpredictable mild stress with pregnancy was used. ESK was injected into postpartum mice, and behavioral tests were conducted to predict the severity of symptoms at the end of lactation and in the offspring after adulthood. Both mice with PPD and their offspring showed significant anxiety- and depression-like behaviors that were ameliorated with the ESK intervention. ESK enhanced exploratory behavior in unfamiliar environments, increased the preference for sucrose, and ameliorated the impaired BDNF/AKT/mTOR signaling in the frontal and hippocampal regions in mice. Thus, ESK may have great potential in treating PPD and decreasing the incidence of depression in offspring.

Molecular signatures of astrocytes and microglia maladaptive responses to acute stress are rescued by a single administration of ketamine in a rodent model of PTSD

Stress affects the brain and alters its neuroarchitecture and function; these changes can be severe and lead to psychiatric disorders. Recent evidence suggests that astrocytes and microglia play an essential role in the stress response by contributing to the maintenance of cerebral homeostasis. These cells respond rapidly to all stimuli that reach the brain, including stressors. Here, we used a recently validated rodent model of post-traumatic stress disorder in which rats can be categorized as resilient or vulnerable after acute inescapable footshock stress. We then investigated the functional, molecular, and morphological determinants of stress resilience and vulnerability in the prefrontal cortex, focusing on glial and neuronal cells. In addition, we examined the effects of a single subanesthetic dose of ketamine, a fast-acting antidepressant recently approved for the treatment of resistant depression and proposed for other stress-related psychiatric disorders. The present results suggest a prompt glial cell response and activation of the NF-κB pathway after acute stress, leading to an increase in specific cytokines such as IL-18 and TNF-α. This response persists in vulnerable individuals and is accompanied by a significant change in the levels of critical glial proteins such as S100B, CD11b, and CX43, brain trophic factors such as BDNF and FGF2, and proteins related to dendritic arborization and synaptic architecture such as MAP2 and PSD95. Administration of ketamine 24 h after the acute stress event rescued many of the changes observed in vulnerable rats, possibly contributing to support brain homeostasis. Overall, our results suggest that pivotal events, including reactive astrogliosis, changes in brain trophic factors, and neuronal damage are critical determinants of vulnerability to acute traumatic stress and confirm the therapeutic effect of acute ketamine against the development of stress-related psychiatric disorders.

Role of Inflammatory Mechanisms in Major Depressive Disorder: From Etiology to Potential Pharmacological Targets

The involvement of central and peripheral inflammation in the pathogenesis and prognosis of major depressive disorder (MDD) has been demonstrated. The increase of pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, IL-18, and TNF-α) in individuals with depression may elicit neuroinflammatory processes and peripheral inflammation, mechanisms that, in turn, can contribute to gut microbiota dysbiosis. Together, neuroinflammation and gut dysbiosis induce alterations in tryptophan metabolism, culminating in decreased serotonin synthesis, impairments in neuroplasticity-related mechanisms, and glutamate-mediated excitotoxicity. This review aims to highlight the inflammatory mechanisms (neuroinflammation, peripheral inflammation, and gut dysbiosis) involved in the pathophysiology of MDD and to explore novel anti-inflammatory therapeutic approaches for this psychiatric disturbance. Several lines of evidence have indicated that in addition to antidepressants, physical exercise, probiotics, and nutraceuticals (agmatine, ascorbic acid, and vitamin D) possess anti-inflammatory effects that may contribute to their antidepressant properties. Further studies are necessary to explore the therapeutic benefits of these alternative therapies for MDD.

Psychopharmacological Approaches for Neural Plasticity and Neurogenesis in Major Depressive Disorders

Major depressive disorder (MDD) is a mental health disorder associated with cognitive impairment, dysregulated appetite, fatigue, insomnia or hypersomnia, and severe mood changes that significantly impact the ability of the affected individual to perform day-to-day tasks, leading to suicide in the worst-case scenario. As MDD is becoming more prevalent, affecting roughly 300 million individuals worldwide, its treatment has become a major point of interest. Antidepressants acting as selective serotonin reuptake inhibitors (SSRIs) are currently used as the first line of treatment for MDD. Other antidepressants currently used for the treatment of MDD include the serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs). However, although effective in alleviating symptoms of MDD, most antidepressants require weeks or even months of regular administration prior to eliciting a rational clinical effect. Owing to the strong evidence showing a relationship between neural plasticity, neurogenesis, and MDD, researchers have also looked at the possibility of using treatment modalities that target these processes in an attempt to improve clinical outcome. The overarching aim of this chapter is to highlight the role of neural plasticity and neurogenesis in the pathophysiology of MDD and discuss the most recently studied treatment strategies that target these processes by presenting supporting evidence from both animal and human studies.

The Patient's Perspective on the Effects of Intranasal Esketamine in Treatment-Resistant Depression

The effectiveness of the esketamine nasal spray (ESK-NS) for treatment-resistant depression (TRD) has been confirmed by real-world studies. Available evidence derived from clinician-rated assessments might differ from patients' perceptions about the helpfulness of treatments. We aimed to verify the effect of ESK-NS from patients' view in 25 TRD patients (56% males, 55.1 ± 10.9 years) treated with ESK-NS (mean dose: 78.4 ± 11.43 mg) for three months and evaluated at different time-points through clinician-rated and self-administered scales, assessing changes in depression, anhedonia, sleep, cognition, suicidality, and anxiety. We observed an overall early improvement that lasted over time (endpoint total score reduction in Montgomery-Åsberg Depression Rating Scale, p < 0.001, Beck Depression Inventory, p = 0.003). Patients reported a significant self-rated decrease in anhedonia at two months (Snaith-Hamilton Pleasure Scale, p = 0.04) and in suicide ideation at endpoint (BDI subitem 9, p = 0.039) vs. earlier improvements detected by clinicians (one-month reduction in MADRS subitem 8, p = 0.005, and subitem 10, p = 0.007). These findings confirm the effectiveness of a three-month treatment with ESK-NS in TRD patients, highlighting an overall overlapping response from patients' and clinicians' perspectives, although with some differential effects on specific symptoms at given time-points. Including patients' viewpoints in routine assessments could inform clinical practice, ensuring a better characterization of clinical phenotypes to deliver personalized interventions.