Increased oxidation of RNA despite reduced mitochondrial respiration after chronic electroconvulsive stimulation of rat brain tissue

Restoration of mitochondrial energy metabolism by electroconvulsive therapy in adolescent and juvenile mice

Background

Adolescent depression is an increasingly serious public health issue, and traditional treatment methods often have side effects or limited efficacy. Electroconvulsive therapy (ECT), a widely used treatment for severe depression, has recently gained attention for its potential in treating adolescent depression. Previous studies suggest that mitochondrial dysfunction is closely related to the onset of depression. Therefore, investigating the mechanism by which ECT alleviates depressive symptoms through the improvement of mitochondrial energy metabolism is of great significance.

Methods

This study employed the chronic unpredictable mild stress (CUMS) mouse model to assess the effects of ECT on depression-like behaviors through the sucrose preference test, open field test, and tail suspension test. Additionally, mitochondrial energy metabolism markers, including ATP levels, oxygen consumption rate (OCR), lactate, and pyruvate, were measured in both mouse and human plasma to evaluate the effects of ECT on mitochondrial function.

Results

The results showed that ECT significantly improved depression-like and anxiety-like behaviors in mice, as evidenced by the reversal of abnormal behaviors in the sucrose preference test, open field test, and tail suspension test. Analysis of plasma mitochondrial energy metabolism markers revealed that ECT significantly increased ATP levels, restored OCR, reduced lactate accumulation, and increased pyruvate levels. These findings suggest that ECT alleviates depressive symptoms by restoring mitochondrial energy metabolism and improving brain energy supply.

Conclusion

This study systematically explored the potential mechanism by which ECT alleviates adolescent depression through the improvement of mitochondrial energy metabolism. The results indicate that ECT not only effectively alleviates depressive symptoms but also provides new insights and experimental evidence for the treatment of adolescent depression through mitochondrial function restoration. Future research could further investigate how to combine drug treatments to enhance mitochondrial function, improve ECT efficacy, and evaluate the effects of ECT in different depression subtypes, providing guidance for personalized clinical treatment.

Altered serum glutathione disulfide levels in acute relapsed schizophrenia are associated with clinical symptoms and response to electroconvulsive therapy

BACKGROUND

The pathophysiological mechanisms of schizophrenia are complex and not fully elucidated. This study aimed to investigate changes to total glutathione (T-GSH), glutathione disulfide (GSSG), reduced glutathione (GSH), and the GSH/GSSG ratio before and after electroconvulsive therapy (ECT) for patients with acute relapse of schizophrenia and associations with clinical symptoms.

METHODS

The study cohort included 110 patients with acute relapse of schizophrenia and 55 healthy controls. All patients received 8-10 sessions of ECT. Clinical symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

As compared to the healthy controls, schizophrenia patients had decreased baseline GSSG levels (t = -2.115, p = 0.036) and elevated GSH/GSSG ratios (t = 2.141, p = 0.034). Baseline GSSG levels were negatively correlated with both PANSS total scores (beta = -0.369, t = -4.108, p < 0.001) and positive symptom scores (beta = -0.332, t = -3.730, p < 0.001), while changes to GSSG levels were positively correlated with improvements in PANSS total scores (r = 0.392, p < 0.001) and positive symptom scores (r = 0.293, p = 0.005) after ECT treatment. In treatment responders, GSSG levels were significantly increased (t = -2.817, p = 0.006) and GSH/GSSG ratios were decreased (t = 4.474, p < 0.001), as compared to before ECT, with baseline T-GSH (B = 0.734, OR = 2.083, 95%CI:1.287-3.372, p = 0.003), GSSG (B = -2.720, OR = 0.066, 95%CI:0.011-0.390, p = 0.003), and GSH/GSSG ratio (B = -1.013, OR = 0.363, 95%CI:0.142-0.930, p = 0.035) predictive of clinical improvement.

CONCLUSION

Patients with schizophrenia exhibit significant redox imbalance, and GSSG levels may serve as a potential biomarker to evaluate and predict ECT outcomes.

An in silico kinetic model of 8-oxo-7,8-dihydro-2-deoxyguanosine and 8-oxo-7,8-dihydroguanosine metabolism from intracellular formation to urinary excretion

Oxidatively generated DNA damage is of paramount importance in a wide range of physiological and pathophysiological processes. Urinary 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is often used as an outcome marker in studies on the role of oxidatively generated DNA damage, but its exact relation to intracellular damage levels and variations in DNA repair have been unclear. Using a new approach of quantitative kinetic modeling inspired by pharmacokinetics, we find evidence that in steady state - i.e. when systemic consequences of given change in damage or cellular removal rates have stabilized - the urinary excretion of 8-oxodG is closely correlated to rates of damage and intracellular 8-oxodG levels, but independent of the rate of cellular removal. Steady state was calculated to occur within approximately 12 h. A similar pattern was observed in a model of the corresponding RNA marker 8-oxo-7,8-dihydroguanosine (8-oxoGuo), but with steady-state occurring slower (up to 5 d). These data have significant implications for the planning of studies and interpretation of data involving urinary 8-oxodG/8-oxoGuo excretion as outcome.HighlightsThe kinetics of 8-oxodG/8-oxoGuo formation, removal and excretion were simulated in silico.The model was based on existing data on 8-oxodG/8-oxoGuo levels and removal/excretion rates.Intracellular 8-oxodG/8-oxoGuo was closely correlated with urinary excretion in steady state.Changes in removal rates did not influence urinary excretion of 8-oxodG/8-oxoGuo.

Molecular Biomarkers of Electroconvulsive Therapy Effects and Clinical Response: Understanding the Present to Shape the Future

Electroconvulsive therapy (ECT) represents an effective intervention for treatment-resistant depression (TRD). One priority of this research field is the clarification of ECT response mechanisms and the identification of biomarkers predicting its outcomes. We propose an overview of the molecular studies on ECT, concerning its course and outcome prediction, including also animal studies on electroconvulsive seizures (ECS), an experimental analogue of ECT. Most of these investigations underlie biological systems related to major depressive disorder (MDD), such as the neurotrophic and inflammatory/immune ones, indicating effects of ECT on these processes. Studies about neurotrophins, like the brain-derived neurotrophic factor (BDNF) and the vascular endothelial growth factor (VEGF), have shown evidence concerning ECT neurotrophic effects. The inflammatory/immune system has also been studied, suggesting an acute stress reaction following an ECT session. However, at the end of the treatment, ECT produces a reduction in inflammatory-associated biomarkers such as cortisol, TNF-alpha and interleukin 6. Other biological systems, including the monoaminergic and the endocrine, have been sparsely investigated. Despite some promising results, limitations exist. Most of the studies are concentrated on one or few markers and many studies are relatively old, with small sample sizes and methodological biases. Expression studies on gene transcripts and microRNAs are rare and genetic studies are sparse. To date, no conclusive evidence regarding ECT molecular markers has been reached; however, the future may be just around the corner.

Ketamine treatment protects against oxidative damage and the immunological response induced by electroconvulsive therapy

BACKGROUND

Electroconvulsive therapy (ECT) is often recommended for major depressive disorder (MDD) for those who do not respond to the first and second antidepressant trials. A combination of two therapies could improve antidepressant efficacy. Thus, this study aimed to investigate the synergistic effects of ECT combined to antidepressants with a different mechanism of action.

METHODS

Rats were treated once a day, for five days with ketamine (5 mg/kg), fluoxetine (1 mg/kg), and bupropion (4 mg/kg) alone or in combination with ECT (1 mA; 100 V). After, oxidative damage and antioxidant capacity were assessed in the prefrontal cortex (PFC) and hippocampus, and pro-inflammatory cytokines levels were evaluated in the serum.

RESULTS

ECT alone increased lipid peroxidation in the PFC and hippocampus. In the PFC of rats treated with ECT in combination with fluoxetine and bupropion, and in the hippocampus of rats treated with ECT combined with ketamine and bupropion there was a reduction in the lipid peroxidation. The nitrite/nitrate was increased by ECT alone but reverted by combination with ketamine in the hippocampus. Superoxide dismutase (SOD) was increased by ECT and maintained by fluoxetine and bupropion in the PFC. ECT alone increased interleukin-1β (IL-1β) and the administration of ketamine was able to revert this increase showing a neuroprotective effect of this drug when in combination with ECT.

CONCLUSION

The treatment with ECT leads to an increase in oxidative damage and alters the immunological system. The combination with ketamine was able to protect against oxidative damage and the immunological response induced by ECT.

Effects of electroconvulsive shock on neuro-immune responses: Does neuro-damage occur?

Electroconvulsive therapy (ECT) is one of the most effective treatments for treatment-resistant depression. However, this treatment may produce memory impairment. The mechanisms of the cognitive adverse effects are not known. Neuroimmune response is related to the cognitive deficits. By reviewing the available animal literature, we examined the glia activation, inflammatory cytokines, neuron oxidative stress responses, and neural morphological changes following electroconvulsive shock (ECS) treatment. The studies showed that ECS activates microglia, upregulates neuro-inflammatory cytokines, and increases oxidative stress responses. But these effects are rapid and may be transient. They normalize as ECS treatment continues, suggesting endogenous neuroprotection may be mobilized. The transient changes are well in line with the clinical observations that ECT usually does not cause significant long-lasting retrograde amnesia. The longitudinal studies will be particularly important to explore the dynamic changes of neuroplasticity following ECT (Jonckheere et al., 2018). Investigating the neuroplasticity changes in animals that suffered chronic stress may also be crucial to giving support to the translation of preclinical research.