Brain cytochrome-c-oxidase as a marker of mitochondrial function: A pilot study in major depression using NIRS

Physical activity as a promoter of stress resilience: An analysis of behavioral effects and brain connectivity with cytochrome c-oxidase activity in adult male Wistar rats

Physical activity (PA) is very beneficial for physical and mental health. This study aims to examine the resilience-inducting effect of PA in adult male Wistar rats exposed to unpredictable chronic mild stress (UCMS). Furthermore, we analyzed the influence of PA on behavioral tasks and functional brain connectivity with cytochrome c oxidase technique. The cytochrome c oxidase (CCO) is a mitochondrial enzyme involved in oxidative phosphorylation and ATP generation. For this analysis, we included five groups: Basal (n = 10, to determine the basal level of brain activity), Behav (n = 15, subjected exclusively to behavioral tests), PA (n = 10, exposed to physical activity), UCMS (n = 15, subjected to a stress protocol) and PA + UCMS (n = 15, exposed to PA prior to stress). The UCMS protocol consisted of randomly presenting several different stressors over four consecutive weeks. We evaluated several behaviors of the Behav, UCMS, and PA + UCMS groups. This assessment includes the hedonic responses using the sucrose consumption task, unconditioned anxiety with the zero maze, and coping strategies assessed with the cat odor test. The UCMS group showed an anhedonia profile and increased anxiety compared with the other groups. Although in the exposure to cat odor test, the PA + UCMS remained for the same time in the cat odor compartment as the other groups, it did not approach the odor, showing that it detected the risk. This response is more adaptive than the responses of the UCMS and Behav groups. An exploratory analysis of the cerebral connections showed an increase in CCO activity in the UCMS group compared to the other groups. This overactivity was reduced in dorsal Cornu Ammonis 3(dCA3) by prior PA. In this region, PA + UCMS showed similar activity as the groups not subjected to chronic stress. Therefore, PA can prevent the harmful effects of chronic stress on dCA3.

Review of measurements and imaging of cytochrome-c-oxidase in humans using near-infrared spectroscopy: an update

This review examines advancements in the measurement and imaging of oxidized cytochrome-c-oxidase (oxCCO) using near-infrared spectroscopy (NIRS) in humans since 2016. A total of 34 published papers were identified, with a focus on both adult and neonate populations. The NIRS-derived oxCCO signal has been demonstrated to correlate with physiological parameters and hemodynamics. New instrumentation, such as systems that allow the imaging of changes of oxCCO with diffuse optical tomography or combine the oxCCO measurement with diffuse correlation spectroscopy measures of blood flow, have advanced the field in the past decade. However, variability in its response across different populations and paradigms and lack of standardization limit its potential as a reliable and valuable indicator of brain health. Future studies should address these issues to fulfill the vision of oxCCO as a clinical biomarker.

Applications of near-infrared spectroscopy in epilepsy, with a focus on mitochondrial disorders

Mitochondrial diseases are inherited disorders that impede the mitochondria's ability to produce sufficient energy for the cells. They can affect different parts of the body, notably the brain. Neurological symptoms and epilepsy are prevalent in patients with mitochondrial disorders. The epileptogenicity of mitochondrial disorder is a complex process involving the intricate interplay between abnormal energy metabolism and neuronal activity. Several modalities have been used to detect seizures in different disorders including mitochondrial disorders. EEG serve as the gold standard for diagnosis and localization, commonly complemented by additional imaging modalities to enhance source localization. In the current work, we propose the use of functional near-infrared spectroscopy (fNIRS) to identify the occurrence of epilepsy and seizure in patients with mitochondrial disorders. fNIRS proves an advantageous imaging technique due to its portability and insensitivity to motion especially for imaging infants and children. It has added a valuable factor to our understanding of energy metabolism and neuronal activity. Its real-time monitoring with high spatial resolution supplements traditional diagnostic tools such as EEG and provides a comprehensive understanding of seizure and epileptogenesis. The utility of fNIRS extends to its ability to detect changes in Cytochrome c oxidase (CcO) which is a crucial enzyme in cellular respiration. This facet enhances our insight into the metabolic dimension of epilepsy related to mitochondrial dysfunction. By providing valuable insights into both energy metabolism and neuronal activity, fNIRS emerges as a promising imaging technique for unveiling the complexities of mitochondrial disorders and their neurological manifestations.

Prefrontal photobiomodulation produces beneficial mitochondrial and oxygenation effects in older adults with bipolar disorder

There is growing evidence of mitochondrial dysfunction and prefrontal cortex (PFC) hypometabolism in bipolar disorder (BD). Older adults with BD exhibit greater decline in PFC-related neurocognitive functions than is expected for age-matched controls, and clinical interventions intended for mood stabilization are not targeted to prevent or ameliorate mitochondrial deficits and neurocognitive decline in this population. Transcranial infrared laser stimulation (TILS) is a non-invasive form of photobiomodulation, in which photons delivered to the PFC photo-oxidize the mitochondrial respiratory enzyme, cytochrome-c-oxidase (CCO), a major intracellular photon acceptor in photobiomodulation. TILS at 1064-nm can significantly upregulate oxidized CCO concentrations to promote differential levels of oxygenated vs. deoxygenated hemoglobin (HbD), an index of cerebral oxygenation. The objective of this controlled study was to use non-invasive broadband near-infrared spectroscopy to assess if TILS to bilateral PFC (Brodmann area 10) produces beneficial effects on mitochondrial oxidative energy metabolism (oxidized CCO) and cerebral oxygenation (HbD) in older (≥50 years old) euthymic adults with BD (N = 15). As compared to sham, TILS to the PFC in adults with BD increased oxidized CCO both during and after TILS, and increased HbD concentrations after TILS. By significantly increasing oxidized CCO and HbD concentrations above sham levels, TILS has the potential ability to stabilize mitochondrial oxidative energy production and prevent oxidative damage in the PFC of adults with BD. In conclusion, TILS was both safe and effective in enhancing metabolic function and subsequent hemodynamic responses in the PFC, which might help alleviate the accelerated neurocognitive decline and dysfunctional mitochondria present in BD.

Deciphering the Mysterious Relationship between the Cross-Pathogenetic Mechanisms of Neurodegenerative and Oncological Diseases

The relationship between oncological pathologies and neurodegenerative disorders is extremely complex and is a topic of concern among a growing number of researchers around the world. In recent years, convincing scientific evidence has accumulated that indicates the contribution of a number of etiological factors and pathophysiological processes to the pathogenesis of these two fundamentally different diseases, thus demonstrating an intriguing relationship between oncology and neurodegeneration. In this review, we establish the general links between three intersecting aspects of oncological pathologies and neurodegenerative disorders, i.e., oxidative stress, epigenetic dysregulation, and metabolic dysfunction, examining each process in detail to establish an unusual epidemiological relationship. We also focus on reviewing the current trends in the research and the clinical application of the most promising chemical structures and therapeutic platforms that have a modulating effect on the above processes. Thus, our comprehensive analysis of the set of molecular determinants that have obvious cross-functional pathways in the pathogenesis of oncological and neurodegenerative diseases can help in the creation of advanced diagnostic tools and in the development of innovative pharmacological strategies.

Urine based near-infrared spectroscopy analysis reveals a noninvasive and convenient diagnosis method for cancers: a pilot study

Background

The challenges in cancer diagnosis underline the need for continued research and development of new diagnostic tools and methods. This study aims to explore an effective, noninvasive, and convenient diagnostic tool using urine based near-infrared spectroscopy (NIRS) analysis combined with machine learning algorithm.

Methods

Urine samples were collected from a total of 327 participants, including 181 cancer cases and 146 healthy controls. These participants were randomly spit into train set (n = 218) and test set (n = 109). NIRS analysis (4,000 ∼10,000 cm-1) was performed for each sample in both train and test sets. Five pretreatment methods, including Savitzky-Golay (SG) smoothing, multiplicative scatter correction (MSC), baseline removal (BSL) with fitting polynomials to be used as baselines, the first derivative (DERIV1), and the second derivative (DERIV2), and combination with "scaling" and "center", were investigated. Then partial least-squares (PLS) and linear support-vector machine (SVM) classification models were established, and prediction performance was evaluated in test set.

Results

NIRS had greatly overlapping in peaks, and PCA analysis failed in separation between cancers and healthy controls. In modeling with urine based NIRS data, PLS model showed its highest prediction accuracy of 0.780, with DERIV2, "scaling" and "center" pretreatment, while linear SVM displayed its best prediction accuracy of 0.844, with raw NIRS. With optimization in SVM, the prediction accuracy could improve to 0.862, when the top 262 features were involved as variables.

Discussion

This pilot study combining urine based NIRS analysis and machine learning is effective and convenient that might facilitate in cancer diagnosis, encouraging further evaluation with a large-size multi-center study.

Optical neuroimaging: advancing transcranial magnetic stimulation treatments of psychiatric disorders

Transcranial magnetic stimulation (TMS) has been established as an important and effective treatment for various psychiatric disorders. However, its effectiveness has likely been limited due to the dearth of neuronavigational tools for targeting purposes, unclear ideal stimulation parameters, and a lack of knowledge regarding the physiological response of the brain to TMS in each psychiatric condition. Modern optical imaging modalities, such as functional near-infrared spectroscopy and diffuse optical tomography, are promising tools for the study of TMS optimization and functional targeting in psychiatric disorders. They possess a unique combination of high spatial and temporal resolutions, portability, real-time capability, and relatively low costs. In this mini-review, we discuss the advent of optical imaging techniques and their innovative use in several psychiatric conditions including depression, panic disorder, phobias, and eating disorders. With further investment and research in the development of these optical imaging approaches, their potential will be paramount for the advancement of TMS treatment protocols in psychiatry.

Investigating the association between depression and cerebral haemodynamics-A systematic review and meta-analysis

BACKGROUND

Vascular mechanisms may play a role in depression. The aim of this review is to summarise the evidence on alterations in cerebral haemodynamics in depression.

METHODS

MEDLINE (1946- present), Embase (1947-present), Web of Science (1970-present), PsycINFO (1984-present), CINAHL (1976-present) and CENTRAL were searched using a predefined search strategy. A meta-analysis was conducted in four groups: 1) global cerebral blood flow (CBF) in ml/min/100 g, 2) CBF velocity (CBFv) in cm/s (maximum flow of left middle cerebral artery, 3) combined CBF and CBFv, 4) Ratio of uptake of Tc 99 m HMPAO (region of interest compared to whole brain). Data are presented as mean difference or standardised mean difference and 95% confidence interval (95% CI). A narrative synthesis of the remaining studies was performed.

RESULTS

87 studies were included. CBF was significantly reduced in depressed patients compared to HC [15 studies, 538 patients, 416 HC, MD: -2.24 (95% CI -4.12, -0.36), p = 0.02, I² = 64%]. There were no statistically significant differences in other parameters. The narrative synthesis revealed variable changes in CBF in depressed patients, particularly affecting the anterior cingulate and prefrontal cortices.

LIMITATIONS

There were various sources of heterogeneity including the severity of depression, use of antidepressant medication, imaging modality used and reporting of outcomes. All of these factors made direct comparisons between studies difficult.

CONCLUSIONS

The reduction in CBF in depressed patients compared to HCs may indicate a role for assessment and CBF altering interventions in high-risk groups. However, results were inconsistent across studies, warranting further work to investigate specific subgroups.

Mitochondrial, exosomal miR137-COX6A2 and gamma synchrony as biomarkers of parvalbumin interneurons, psychopathology, and neurocognition in schizophrenia

Early detection and intervention in schizophrenia requires mechanism-based biomarkers that capture neural circuitry dysfunction, allowing better patient stratification, monitoring of disease progression and treatment. In prefrontal cortex and blood of redox dysregulated mice (Gclm-KO ± GBR), oxidative stress induces miR-137 upregulation, leading to decreased COX6A2 and mitophagy markers (NIX, Fundc1, and LC3B) and to accumulation of damaged mitochondria, further exacerbating oxidative stress and parvalbumin interneurons (PVI) impairment. MitoQ, a mitochondria-targeted antioxidant, rescued all these processes. Translating to early psychosis patients (EPP), blood exosomal miR-137 increases and COX6A2 decreases, combined with mitophagy markers alterations, suggest that observations made centrally and peripherally in animal model were reflected in patients' blood. Higher exosomal miR-137 and lower COX6A2 levels were associated with a reduction of ASSR gamma oscillations in EEG. As ASSR requires proper PVI-related networks, alterations in miR-137/COX6A2 plasma exosome levels may represent a proxy marker of PVI cortical microcircuit impairment. EPP can be stratified in two subgroups: (a) a patients' group with mitochondrial dysfunction "Psy-D", having high miR-137 and low COX6A2 levels in exosomes, and (b) a "Psy-ND" subgroup with no/low mitochondrial impairment, including patients having miR-137 and COX6A2 levels in the range of controls. Psy-D patients exhibited more impaired ASSR responses in association with worse psychopathological status, neurocognitive performance, and global and social functioning, suggesting that impairment of PVI mitochondria leads to more severe disease profiles. This stratification would allow, with high selectivity and specificity, the selection of patients for treatments targeting brain mitochondria dysregulation and capture the clinical and functional efficacy of future clinical trials.

Oxyhaemoglobin Level Measured Using Near-Infrared Spectrometer Is Associated with Brain Mitochondrial Dysfunction After Cardiac Arrest in Rats

Cerebral blood oxygenation (CBO), measured using near-infrared spectroscopy (NIRS), can play an important role in post-cardiac arrest (CA) care as this emerging technology allows for noninvasive real-time monitoring of the dynamic changes of tissue oxygenation. We recently reported that oxyhaemoglobin (oxy-Hb), measured using NIRS, may be used to evaluate the quality of chest compressions by monitoring the brain tissue oxygenation, which is a critical component for successful resuscitation. Mitochondria are the key to understanding the pathophysiology of post-CA oxygen metabolism. In this study, we focused on mitochondrial dysfunction, aiming to explore its association with CBO parameters such as oxy-Hb and deoxyhaemoglobin (deoxy-Hb) or tissue oxygenation index (TOI). Male Sprague-Dawley rats were used in the study. We applied NIRS between the nasion and the upper cervical spine. Following 10 min of CA, the rats underwent cardiopulmonary resuscitation (CPR) with a bolus injection of 20 μg/kg epinephrine. At 10 and 20 min after CPR, brain, and kidney tissues were collected. We isolated mitochondria from these tissues and evaluated the association between CBO and mitochondrial oxygen consumption ratios. There were no significant differences in the mitochondrial yields (10 vs. 20 min after resuscitation: brain, 1.33 ± 0.68 vs. 1.30 ± 0.75 mg/g; kidney, 19.5 ± 3.2 vs. 16.9 ± 5.3 mg/g, respectively). State 3 mitochondrial oxygen consumption rates, known as ADP-stimulated respiration, demonstrated a significant difference at 10 vs. 20 min after CPR (brain, 170 ± 26 vs. 115 ± 17 nmol/min/mg protein; kidney, 170 ± 20 vs. 130 ± 16 nmol/min/mg protein, respectively), whereas there was no significant difference in ADP non-dependent state 4 oxygen consumption rates (brain, 34.0 ± 6.7 vs. 31.8 ± 10 nmol/min/mg protein; kidney, 29.8 ± 4.8 vs. 21.0 ± 2.6 nmol/min/mg protein, respectively). Consequently, the respiratory control ratio (RCR = state 3/state 4) showed a significant difference over time, but this was only noted in the brain (brain, 5.0 ± 0.29 vs. 3.8 ± 0.64; kidney, 5.8 ± 0.53 vs. 6.2 ± 0.25 nmol/min/mg protein, respectively). The oxy-Hb levels had a dynamic change after resuscitation, and they had a significant association with the RCR of the brain mitochondria (r = 0.8311, p = 0.0102), whereas deoxy-Hb and TOI did not (r = -0.1252, p = 0.7677; r = 0.4186, p = 0.302, respectively). The RCRs of the kidney mitochondria did not have a significant association with CBO (oxy-Hb, r = -0.1087, p = 0.7977; deoxy-Hb, r = 0.1565, p = 0.7113; TOI, r = -0.1687, p = 0.6896, respectively). The brain mitochondrial respiratory dysfunction occurred over time, and it was seen at the time points between 10 and 20 min after CPR. The oxy-Hb level was associated with brain mitochondrial dysfunction during the early post-resuscitation period.

Analysis of Suicidal Behavior and Chronicity of Depressive Symptoms in the Presence of Hypovitaminosis D

Background:

One of the risk factors for suicide includes the presence of depressive disorder and symptoms, which may be related to the reduction of 25-hydroxyvitamin D serum levels. In this scenario, evidence shows vitamin D deficiency as an important aspect, directly related to depressive disorder chronicity.

Objective:

To assess the association between Vitamin D serum levels and the intensity of depressive symptoms and suicidal behavior in a clinical sample of depressed patients.

Methods:

A cross-sectional study with 146 patients aged between 18 and 59, seen in two psychiatry ambulatories. Data collection involved measurement of serum 25-hydroxyvitamin D levels and assessment of the intensity of depressive symptoms and suicide risk.

Results:

In the sample, 35% presented low Vitamin D serum levels and, in these individuals, the incidence of family history of Depressive Disorder (95.2%) and chronicity of severe depressive symptoms (47.8%) was higher. As to suicidal behavior, both groups presented high active suicide risk, with higher rates in the group with hypovitaminosis D. Only suicidal ideation was linked to lower Vitamin D levels (67.4% p= 0,005).

Conclusion:

In this study, hypovitaminosis D was associated with negative mental health outcomes, such as more severe chronicity of depressive symptoms and suicidal behavior, characterized by active suicidal ideation.

Blood-based mitochondrial respiratory chain function in major depression

Mitochondrial dysfunction has been implicated in major depressive disorder (MDD). A measure of mitochondrial respiratory chain (RC) enzymatic activity-the Mitochondrial Health Index (MHI)-has previously been found to correlate with stress and emotional states in caregivers. We here report mitochondrial RC activities, mitochondrial DNA copy number (mtDNAcn), and the composite MHI in unmedicated and somatically healthy subjects with MDD (n = 47) and healthy controls (HC) (n = 11). We also explore, in a subset of the MDD sample (n = 33), whether these markers are associated with response to 8 weeks of SSRI treatment. Mitochondrial RC complexes I, II, IV, citrate synthase (CS), mtDNAcn, and the MHI were assayed in peripheral blood mononuclear cells. Treatment response was defined as >50% decrease on the 25-item Hamilton Depression Rating Scale (HRDS-25). There were no significant differences in MHI or any of the mitochondrial markers between MDD subjects and HCs. Compared to SSRI nonresponders, SSRI responders had significantly higher baseline mitochondrial content markers CS (p = 0.02) and mtDNAcn (p = 0.02), and higher complex I activity (p = 0.01). Complex II activity increased significantly over treatment, irrespective of clinical response (p = 0.03). Complex I activity decreased in responders (n = 9), but increased in nonresponders (n = 18) (group x time interaction, p = 0.02). Absolute treatment-associated change in HDRS-25 scores correlated significantly with change in complex I activity between baseline and week 8 (r = 0.47, p = 0.01). Although mitochondrial markers did not distinguish MDD from controls, they did distinguish SSRI responders from nonresponders. If larger studies validate these mitochondrial differences, they may become useful biomarkers and identify new drug targets.

Predictive value and regulatory mechanism of serum miR-499a-5p on myocardial dysfunction in sepsis

Background

This study sought to investigate the predictive value and regulatory mechanism of serum miR-499a-5p in sepsis-induced myocardial dysfunction (SIMD).

Methods

A total of 60 patients with sepsis and 60 healthy volunteers were enrolled in this study. The serum levels of miRNAs (miR-451, miR-378 and miR-499a-5p) were detected. Receiver operating characteristic curve and logistic regression analysis were used to evaluate the diagnostic and prognostic value of miR-499a-5p in SIMD patients. AC16 cells were used to establish SIMD model in vitro using lipopolysaccharide (LPS). An analysis was conducted for miR-499a-5p expression, cell viability, and the concentration of creatine kinase-MB isoform (CK-MB), brain natriuretic peptide (BNP), superoxide dismutase (SOD) and cytochrome C oxidase IV (COX IV). The downstream target of miR-499a-5p was verified.

Results

Our results revealed a poor expression of miR-499a-5p in the serum of SIMD patients, while no significant difference was evident for miR-451 and miR-378. The level of miR-499a-5p in the survival group was higher than the non-survival group. miR-499a-5p elicited good diagnostic and prognostic value for SIMD. Our findings revealed that miR-499a-5p was decreased significantly in LPS-treated cardiomyocytes. After overexpression of miR-499a-5p, the cell viability increased, and the concentrations of CK-MB and BNP were decreased, while the concentrations of SOD and COX IV were increased. EIF4E was validated as the target of miR-499a-5p. After overexpression of EIF4E, the cell viability was decreased and the concentrations of CK-MB and BNP were increased while the concentrations of SOD and COX IV were decreased.

Conclusion

The level of miR-499a-5p is weak in SIMD patients. miR-499a-5p has a good diagnostic and prognostic value for SIMD by inhibiting EIF4E transcription.

Genotype-driven therapeutic developments in Parkinson's disease

BACKGROUND

Remarkable advances have been reached in the understanding of the genetic basis of Parkinson's disease (PD), with the identification of monogenic causes (mPD) and a plethora of gene loci leading to an increased risk for idiopathic PD. The expanding knowledge and subsequent identification of genetic contributions fosters the understanding of molecular mechanisms leading to disease development and progression. Distinct pathways involved in mitochondrial dysfunction, oxidative stress, and lysosomal function have been identified and open a unique window of opportunity for individualized treatment approaches. These genetic findings have led to an imminent progress towards pathophysiology-targeted clinical trials and potentially disease-modifying treatments in the future.

MAIN BODY OF THE MANUSCRIPT

In this review article we will summarize known genetic contributors to the pathophysiology of Parkinson's disease, the molecular mechanisms leading to disease development, and discuss challenges and opportunities in clinical trial designs.

CONCLUSIONS

The future success of clinical trials in PD is mainly dependent on reliable biomarker development and extensive genetic testing to identify genetic cases. Whether genotype-dependent stratification of study participants will extend the potential application of new drugs will be one major challenge in conceptualizing clinical trials. However, the latest developments in genotype-driven treatments will pave the road to individualized pathophysiology-based therapies in the future.

[The link of platelet cytochrome C-oxidase activity with some clinical parameters of depression in elderly patients]

OBJECTIVE

To search for correlations between platelet cytochrome c-oxidase (COX) activity and the quality of therapeutic outcomes and other clinical parameters of depression in elderly patients.

MATERIAL AND METHODS

Twenty elderly women, aged 55-78 years, with depressive episodes in recurrent depressive disorder (RDD) or bipolar affective disorder (BD) were studied. COX activity and severity of depression were evaluated twice: before the beginning of antidepressant treatment and at the 28-th day of the therapy, using the Hamilton Depression Rating Scale (HAMD-17) and the Hamilton Anxiety Rating Scale (HAM-A).

RESULTS

Significant correlations were revealed between platelet COX activity and some clinical parameters of the disease and the severity of depression in patients after treatment. The baseline level of the platelet COX activity was correlated with the age of disease onset (R= -0.63, p=0.003) and its duration (R=0.55, p=0.010). Significant negative correlations were also found between the baseline level of COX activity and depression severity (HAMD-17 total score) (R= -0.48, p=0.032) and the severity of anxiety (HARSHAM-A total score) (R= -0.54, p=0.010) after 28-day treatment.

CONCLUSION

This pilot study has revealed a link between platelet COX activity and the severity of depression and anxiety after a 28-day antidepressant therapy. The results indicate the prospects for further study of COX as a biomarker of therapeutic outcomes in elderly patients with depression.

The Use of Vitamin K2 in Patients With Parkinson's Disease and Mitochondrial Dysfunction (PD-K2): A Theranostic Pilot Study in a Placebo-Controlled Parallel Group Design

Background: Despite rapid advances in research on Parkinson's disease (PD), in particular in the elucidation of genetic contributions, no disease-modifying therapy has become available to date.

Objectives: In the proposed project, we aim to investigate the potential effects of vitamin K2 (long-chain menaquinone 7, MK-7) in genetically determined PD with mitochondrial dysfunction.

Methods: A total of 130 study participants (26 biallelic Parkin/PINK1 mutation carriers, 52 sporadic PD patients, and 52 healthy controls) will receive the trial medication (MK-7 or placebo for 1 week). 31P-Magnetic resonance spectroscopy imaging of the forebrain and basal ganglia (31P-MRSI, primary endpoint) as well as other advanced neuroimaging methods, clinical assessment, including quantitative movement analysis, and biomarker sampling will be applied pre- and post-intervention.

Innovation: The proposed project is highly translational as it builds on compelling mechanistic data from animal studies as well as on a small preliminary data set in humans. Patients are selected based on their mutation-related mitochondrial dysfunction and compared to disease and a healthy control group in a personalized medicine approach. We will further investigate how neuroimaging and blood-derived biomarkers can predict individual treatment response in sporadic PD.

Clinical trial registration: This study was registered at the German Clinical Trial Registry (DRKS, DRKS00019932) on the 19th of December 2019.

A proof of concept 'phase zero' study of neurodevelopment using brain organoid models with Vis/near-infrared spectroscopy and electrophysiology

Homeostatic control of neuronal excitability by modulation of synaptic inhibition (I) and excitation (E) of the principal neurons is important during brain maturation. The fundamental features of in-utero brain development, including local synaptic E-I ratio and bioenergetics, can be modeled by cerebral organoids (CO) that have exhibited highly regular nested oscillatory network events. Therefore, we evaluated a 'Phase Zero' clinical study platform combining broadband Vis/near-infrared(NIR) spectroscopy and electrophysiology with studying E-I ratio based on the spectral exponent of local field potentials and bioenergetics based on the activity of mitochondrial Cytochrome-C Oxidase (CCO). We found a significant effect of the age of the healthy controls iPSC CO from 23 days to 3 months on the CCO activity (chi-square (2, N = 10) = 20, p = 4.5400e-05), and spectral exponent between 30-50 Hz (chi-square (2, N = 16) = 13.88, p = 0.001). Also, a significant effect of drugs, choline (CHO), idebenone (IDB), R-alpha-lipoic acid plus acetyl-L-carnitine (LCLA), was found on the CCO activity (chi-square (3, N = 10) = 25.44, p = 1.2492e-05), spectral exponent between 1 and 20 Hz (chi-square (3, N = 16) = 43.5, p = 1.9273e-09) and 30-50 Hz (chi-square (3, N = 16) = 23.47, p = 3.2148e-05) in 34 days old CO from schizophrenia (SCZ) patients iPSC. We present the feasibility of a multimodal approach, combining electrophysiology and broadband Vis-NIR spectroscopy, to monitor neurodevelopment in brain organoid models that can complement traditional drug design approaches to test clinically meaningful hypotheses.

Effect of short-term oral supplementation of crocin on age-related oxidative stress, cholinergic, and mitochondrial dysfunction in rat cerebral cortex

BACKGROUND AND AIM

Aging is associated with oxidative stress and altered cholinergic and mitochondrial function. Crocin is a carotenoid antioxidant that quenches free radicals and protects cells and tissues from oxidation in biological systems. The aim of the present study is to investigate the effect of oral supplementation of Crocin on age-associated oxidative stress, cholinergic, and mitochondrial function in rat cerebral cortex.

MAIN METHODS

The middle-aged (15 months old) rats were segregated into three groups (n = 6): Control (ad-libitum fed +0.9% saline as vehicle), Cro 50 (ad-libitum fed + crocin 50 mg/kg/day), Cro 150 (ad-libitum fed + crocin 150 mg/kg/day). The experiment was scheduled for 45 days. The serum and brain parameters were estimated after euthanasia.

KEY FINDINGS

Crocin supplementation of Cro 50 and Cro 150 displayed a relative decline in body weight gain during the experimental period and significantly reduced age-associated serum triglyceride level over control. In rat cerebral cortex, age-associated macromolecular damage, decline in endogenous antioxidants and an increase in intracellular calcium concentration were significantly reversed due to oral supplementation of Crocin. Cro 150 significantly improved acetylcholine content as a consequence of acetylcholinesterase inhibition. Further, remarkable mitochondrial function was observed in Cro 150 over the control group as determined by citrate synthase and cytochrome C oxidase enzyme activities.

SIGNIFICANCE

Oral supplementation of Crocin significantly reversed age-associated oxidative stress and neuroinflammatory markers. Meanwhile, Cro 150 remarkably improved cholinergic and mitochondrial function over the control group and facilitated further delay in the aging process due to enhanced cognitive effect.

Sex-Specific Effects of Early Life Stress on Brain Mitochondrial Function, Monoamine Levels and Neuroinflammation

Sex differences have been reported in the susceptibility to early life stress and its neurobiological correlates in humans and experimental animals. However, most of the current research with animal models of early stress has been performed mainly in males. In the present study, prolonged maternal separation (MS) paradigm was applied as an animal model to resemble the effects of adverse early experiences in male and female rats. Regional brain mitochondrial function, monoaminergic activity, and neuroinflammation were evaluated as adults. Mitochondrial energy metabolism was greatly decreased in MS females as compared with MS males in the prefrontal cortex, dorsal hippocampus, and the nucleus accumbens shell. In addition, MS males had lower serotonin levels and increased serotonin turnover in the prefrontal cortex and the hippocampus. However, MS females showed increased dopamine turnover in the prefrontal cortex and increased norepinephrine turnover in the striatum, but decreased dopamine turnover in the hippocampus. Sex differences were also found for pro-inflammatory cytokine levels, with increased levels of TNF-α and IL-6 in the prefrontal cortex and hippocampus of MS males, and increased IL-6 levels in the striatum of MS females. These results evidence the complex sex- and brain region-specific long-term consequences of early life stress.

Environmental enrichment effects after early stress on behavior and functional brain networks in adult rats

Early life stress is associated with long-term and pervasive adverse effects on neuroendocrine development, affecting normal cognitive and emotional development. Experimental manipulations like environmental enrichment (EE) may potentially reverse the effects of early life stress induced by maternal separation (MS) paradigm in rodents. However, the functional brain networks involved in the effects of EE after prolonged exposure to MS have not yet been investigated. In order to evaluate possible changes in brain functional connectivity induced by EE after MS, quantitative cytochrome c oxidase (CCO) histochemistry was applied to determine regional brain oxidative metabolism in adult male rats. Unexpectedly, results show that prolonged MS during the entire weaning period did not cause any detrimental effects on spatial learning and memory, including depressive-like behavior evaluated in the forced-swim test, and decreased anxiety-like behavior. However, EE seemed to alter anxiety- and depression-like behaviors in both control and MS groups, but improved spatial memory in the latter groups. Analysis of brain CCO activity showed significantly lower metabolic capacity in most brain regions selected in EE groups probably associated with chronic stress, but no effects of MS on brain metabolic capacity. In addition, principal component analysis of CCO activity revealed increased large-scale functional brain connectivity comprising at least three main networks affected by EE in both MS and control groups. Moreover, EE induced a pattern of functional brain connectivity associated with stress and anxiety-like behavior as compared with non-enriched groups. In conclusion, EE had differential effects on cognition and emotional behavior irrespective of exposure to MS. In view of the remarkable effects of EE on brain function and behavior, implementation of rodent housing conditions should be optimized by evaluating the balance between scientific validity and animal welfare.