Psychological outcomes of COVID-19 survivors at sixth months after diagnose: the role of kynurenine pathway metabolites in depression, anxiety, and stress

Conceptual foundations of acetylcarnitine supplementation in neuropsychiatric long COVID syndrome: a narrative review

Post-acute sequelae of COVID-19 can present as multi-organ pathology, with neuropsychiatric symptoms being the most common symptom complex, characterizing long COVID as a syndrome with a significant disease burden for affected individuals. Several typical symptoms of long COVID, such as fatigue, depressive symptoms and cognitive impairment, are also key features of other psychiatric disorders such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and major depressive disorder (MDD). However, clinically successful treatment strategies are still lacking and are often inspired by treatment options for diseases with similar clinical presentations, such as ME/CFS. Acetylcarnitine, the shortest metabolite of a class of fatty acid metabolites called acylcarnitines and one of the most abundant blood metabolites in humans can be used as a dietary/nutritional supplement with proven clinical efficacy in the treatment of MDD, ME/CFS and other neuropsychiatric disorders. Basic research in recent decades has established acylcarnitines in general, and acetylcarnitine in particular, as important regulators and indicators of mitochondrial function and other physiological processes such as neuroinflammation and energy production pathways. In this review, we will compare the clinical basis of neuropsychiatric long COVID with other fatigue-associated diseases. We will also review common molecular disease mechanisms associated with altered acetylcarnitine metabolism and the potential of acetylcarnitine to interfere with these as a therapeutic agent. Finally, we will review the current evidence for acetylcarnitine as a supplement in the treatment of fatigue-associated diseases and propose future research strategies to investigate the potential of acetylcarnitine as a treatment option for long COVID.

Phase-and disorder-specific differences in peripheral metabolites of the kynurenine pathway in major depression, bipolar affective disorder and schizophrenia

OBJECTIVES

Kynurenine, kynurenic and quinolinic acid are important metabolites in tryptophan metabolism. Due to an involvement in glutamatergic neurotransmission and immune response, previous studies have investigated this pathway in mental disorders such as major depressive disorder (MDD), bipolar disorder (BD) or schizophrenia (SCZ). Tryptophan and kynurenine have been shown to be decreased across disorders, hinting at the missing link how inflammation causes neurotoxicity and psychiatric symptoms. The main aim of our study was to investigate if individual catabolites could serve as diagnostic biomarkers for MDD, BD and SCZ.

METHODS

We measured plasma levels of tryptophan, kynurenine, kynurenic acid, quinolinic acid and ratio of quinolinic acid/kynurenic acid using mass spectrometry in n = 175 participants with acute episodes and after remission, compared with controls.

RESULTS

Decreased levels of all tryptophan catabolites were found in the whole patient group, driven by the difference between BD and HC. Manic and mixed phase BD individuals displayed significantly lower kynurenine and kynurenic acid levels. We could not find significant differences between disorders. Upon reaching remission, changes in catabolite levels partially normalised.

CONCLUSIONS

Our data suggests an involvement of the kynurenine pathway in mental disorders, especially BD but disqualifying those metabolites as biomarkers for differential diagnosis.

COVID-19 exposure and depression-anxiety levels among Saudi adults in the Jazan region: a study with a predominantly female and undergraduate sample

Background

The COVID-19 pandemic has caused significant mental health challenges worldwide, as evidenced by numerous studies indicating high levels of depression and anxiety among individuals. However, the extent of mental health disorders following the pandemic and the association between anxiety and depression and COVID-19 exposure levels in the Jazan region of the Kingdom of Saudi Arabia have received little research attention.

Methods

A convenience sample of 377 participants, predominantly female (85.4%) with undergraduate education (74.5%) and Saudi nationality (92.8%), was included in the study. The study utilized a self-administered questionnaire to collect data from participants between 1st August and 8th September 2022. The questionnaire consisted of four parts, including demographic characteristics, COVID-19 exposure, the Patient Health Questionnaire-9 (PHQ-9) for depression assessment, and the Generalized Anxiety Disorders-7 (GAD-7) for anxiety evaluation. Statistical techniques such as descriptive statistics, independent t-tests, ANOVA (Analysis of Variance), and regression analysis were employed to analyze the collected data.

Results

The mean age of the study participants was 30.97 years (SD = 9.072). The mean score for COVID-19 exposure was 2.98 (SD = 1.48). The mean level of depression was 7.83 (SD = 6.43), with 20% of participants experiencing moderate to severe depression. Additionally, the study found that the mean score of anxiety level among participants was 6.75 (SD = 6.57), with 26% of the participants experiencing moderate to severe anxiety. Independent t-test revealed significant differences in mean depression and anxiety scores between participants with varying COVID-19 exposure levels (p = 0.001). The regression analysis demonstrated that anxiety levels were significant predictors of depression (p < 0.001). There is a significant difference in the depression mean between participants with high levels of anxiety (≥10) compared to others with levels <10. Furthermore, significant predictors of anxiety levels included either student or unemployment status (p < 0.001), increased age (≥35) (p = 0.049), female gender (p = 0.009), marital status of not being married, divorced, or widowed (p = 0.004), low monthly income (p = 0.019), and increased depression level (p < 0.001).

Conclusion

This study provides evidence of significant depression and anxiety levels among participants, with higher COVID-19 infection exposure correlating with increased scores for both. Anxiety was identified as a significant predictor of depression. Demographic factors, such as employment status, age, gender, and marital status, played a role in influencing anxiety levels. The findings highlight the need for targeted mental health interventions to address the psychological impact of COVID-19 infection exposure and support affected individuals effectively.

Scientific Rationale for the Treatment of Cognitive Deficits from Long COVID

Sustained cognitive deficits are a common and debilitating feature of "long COVID", but currently there are no FDA-approved treatments. The cognitive functions of the dorsolateral prefrontal cortex (dlPFC) are the most consistently afflicted by long COVID, including deficits in working memory, motivation, and executive functioning. COVID-19 infection greatly increases kynurenic acid (KYNA) and glutamate carboxypeptidase II (GCPII) in brain, both of which can be particularly deleterious to PFC function. KYNA blocks both NMDA and nicotinic-alpha-7 receptors, the two receptors required for dlPFC neurotransmission, and GCPII reduces mGluR3 regulation of cAMP-calcium-potassium channel signaling, which weakens dlPFC network connectivity and reduces dlPFC neuronal firing. Two agents approved for other indications may be helpful in restoring dlPFC physiology: the antioxidant N-acetyl cysteine inhibits the production of KYNA, and the α2A-adrenoceptor agonist guanfacine regulates cAMP-calcium-potassium channel signaling in dlPFC and is also anti-inflammatory. Thus, these agents may be helpful in treating the cognitive symptoms of long COVID.

Alterations of the Composition and Neurometabolic Profile of Human Gut Microbiota in Major Depressive Disorder

Major depressive disorder (MDD) is among the most prevalent mental disorders worldwide. Factors causing the pathogenesis of MDD include gut microbiota (GM), which interacts with the host through the gut–brain axis. In previous studies of GM in MDD patients, 16S rRNA sequencing was used, which provided information about composition but not about function. In our study, we analyzed whole metagenome sequencing data to assess changes in both the composition and functional profile of GM. We looked at the GM of 36 MDD patients, compared with that of 38 healthy volunteers. Comparative taxonomic analysis showed decreased abundances of Faecalibacterium prausnitzii, Roseburia hominis, and Roseburia intestinalis, and elevated abundances of Escherichia coli and Ruthenibacterium lactatiformans in the GM of MDD patients. We observed decreased levels of bacterial genes encoding key enzymes involved in the production of arginine, asparagine, glutamate, glutamine, melatonin, acetic, butyric and conjugated linoleic acids, and spermidine in MDD patients. These genes produced signature pairs with Faecalibacterium prausntizii and correlated with decreased levels of this species in the GM of MDD patients. These results show the potential impact of the identified biomarker bacteria and their metabolites on the pathogenesis of MDD, and should be confirmed in future metabolomic studies.

SARS-CoV-2 and monkeypox: what is common and what is not in a present pandemic versus a potential one—a neuropsychiatric narrative review

Pandemic represents challenging medical emergency as it is usually associated with high rates of mortalities and morbidities. Along the last 2 and half years the world has faced the emergence of severe acute respiratory syndrome corona virus 2 pandemic that caught medical agencies and health authorities by surprise and costed more than half billion morbidities and 6 million mortalities. Unfortunately, the way developed countries contained the novel corona virus was unsatisfactory in means of early quarantines as well as obtaining and distributing an effective vaccine. This failure in management might have been responsible for the emergence of a new potential pandemic caused by monkeypox virus. Along the current review article, a detailed comparison is presented between corona virus and monkeypox virus based on virological characteristics, role of corona virus in monkeypox spread, pathogenesis, neuropsychiatric manifestations, and treatment and management. It is obvious that both viruses have a major role in causing various neuropsychiatric manifestations. Neurological manifestations are either bound directly to the virus spread to central and peripheral nervous system or secondary to triggering an immune reaction. Psychiatric ones are mostly related to stigmatization, isolation as well as changes that takes place in neurotransmitters and their metabolites within the nervous system. Dealing properly with monkeypox virus spread through previously learned lessons from corona virus might protect the world from a new pandemic.