Neuroimmunomodulation最新文献

Major Depressive Disorder (MDD) significantly impacts millions worldwide, with limited success in achieving remission for many patients, leading to high disease burden and increased suicide risk. Psychotherapy and antidepressants, although effective, do not provide relief for all, prompting the search for alternative treatments. Ketogenic diets have demonstrated positive effects on brain health. Our study aims to investigate the efficacy of the ketogenic diet in alleviating MDD symptoms, filling a critical gap in psychiatric treatment options and offering a novel dietary approach with potential to mitigate disease burden and enhance mental well-being. This phase randomized controlled trial will evaluate the efficacy of a ten-week program of dietitian counseling and ketogenic meal provision versus an intervention with similar dietetic contact promoting a healthy, insulin-lowering, non-ketogenic diet. The primary outcome is the change in the Patient Health Questionnaire nine-item depression score. Secondary outcomes include cognitive and affective mindfulness, self-efficacy, sleep, cognitive function, work and social adjustment, and various immunological, metabolic, and microbiome markers at weeks 6 and 10. This study addresses a critical gap in depression treatment by exploring the ketogenic diet's potential as a novel intervention. Given the global impact of depression and limitations of current therapies, this research is valuable for its potential neuroprotective and metabolic benefits. It aims to advance psychiatric treatment strategies by clarifying the diet's effects on depression and its underlying mechanisms.

Background: Substantial evidence from epidemiological and clinical studies suggests that exposure to stress during sensitive developmental periods strongly and robustly increases the risk for psychiatric and physical disorders, resulting in reduced longevity. Chronic immune activation has been proposed as one mechanism through which early adverse experiences may become biologically embedded. This paper highlights selected key findings and questions that first emerged in the literature and founded the field and then examines how research methods and questions have evolved over time.

Summary: During the past decades, evidence from preclinical, clinical, and epidemiological studies has accumulated suggesting consequences of early life stress (ELS) exposure for immune function, particularly increased chronic inflammation or inflammatory responses. Scientific approaches to study the effects of ELS on the immune system have changed since the first studies on this topic were published.

Key messages: Across different study designs, species and methods, a consistent association between childhood adversity and a proinflammatory phenotype has been reported. We critically discuss which topics warrant further consideration and how current findings could be used to develop targeted interventions to prevent or reverse the biological embedding of ELS and resultant disease manifestations.

Background For over 130 years, scientists have been suggesting that infection and inflammation may play a role in psychosis and other psychiatric disorders. First attempts to treat psychosis by immune-modulating therapies were made early in the last century; however, after the development of antipsychotics in the 1950s, scientific interest shifted away from immunological aspects of psychiatric disorders to the involvement of catecholamines, in particular dopamine, in psychosis. Summary Antipsychotic treatment was not as successful as expected, so the 1990s saw renewed interest in inflammation and psychoneuroimmunological research in schizophrenia and beyond. In parallel, advances in immunological research methods allowed immunological and inflammatory mechanisms to be studied in more detail. Key Messages Clinical studies and meta-analyses have demonstrated the positive effects of anti-inflammatory treatment in psychiatric disorders. More research is needed to elucidate exactly how immunological mechanisms result in disease pathophysiology, with the aim to improve anti-inflammatory treatments and personalized treatment.

Introduction: Common mental disorders, such as anxiety disorders, depression, and posttraumatic stress disorder (PTSD), present a substantial health and economic burden. The gut microbiome has been associated with these psychiatric disorders via the microbiome-gut-brain axis. However, previous studies have focused on the associations between the gut microbiome and common mental disorders in European, North American and Asian populations. As part of the saNeuroGut Initiative, we assessed associations between gut microbial composition and self-reported symptoms of anxiety, depression and posttraumatic stress among South African adults.

Methods: Participants completed validated, online self-report questionnaires to evaluate symptoms of state anxiety, trait anxiety, depression, and PTSD. Eighty-six stool-derived microbial DNA samples underwent sequencing of the V4 region of the 16S rRNA gene to characterise gut bacterial taxa in the sample.

Results: No significant associations were observed between symptom severity scores and alpha (Shannon and Simpson indices) and beta (Aitchison distances) diversity metrics. Linear regression models revealed that the abundances of Catenibacterium, Collinsella and Holdemanella were significantly positively associated with the severity of posttraumatic stress (PTS) symptoms.

Conclusion: Catenibacterium, Collinsella and Holdemanella have each previously been associated with various psychiatric disorders, with Catenibacterium having been positively associated with symptoms of PTSD in another South African cohort. This study sheds light on the relationship between the human gut microbiome and symptoms of anxiety, depression, and PTS in a South African adult sample.

Introduction: Both sleep deprivation (SD) and inflammation can negatively affect cognitive function. This study aimed to investigate how SD impacts the brain's inflammatory response to lipopolysaccharide (LPS) and its subsequent effects on cognitive functions.

Methods: To this end, male rats were tested through a Morris water maze (MWM) to assess their spatial learning and memory. Also, in vivo field potential recordings (to evaluate synaptic plasticity) were done in the Saline, SD, LPS1 (1 mg/kg/7 days), and LPS1+SD groups. Cytokine levels were measured using an enzyme-linked immunosorbent assay (ELISA).

Results: Based on the results, the LPS1+SD group showed increased total distance and escape latency compared to the other groups in the MWM test. Besides, the LPS1+SD group exhibited a significant decrease in long-term potentiation (LTP) induction and maintenance in the CA1 area of the brain. Finally, the inflammatory cytokine interleukin-1β (IL-1β) levels were significantly higher in the LPS1+SD group than in the Saline group.

Conclusion: These findings suggest that the combined effects of SD and brain inflammatory response can have more harmful effects on cognitive function, LTP, and inflammatory factors than either SD or LPS1 alone.

Background: It was known since the 1940s that pharmacological administration of glucocorticoids can inhibit inflammatory and immune processes, and these hormones are still today among the most widely used therapeutic tools to treat diseases with immune components. However, it became clear later that endogenous glucocorticoids can either support or restrain immune processes.

Summary: Early studies showed that (a) endogenous levels of glucocorticoids can modulate immune cell activity; (b) the immune response itself can stimulate the hypothalamus-pituitary-adrenal (HPA) axis to release glucocorticoids to levels that can exert immunoregulatory effects; (c) immune products, later identified as cytokines, mediate this effect. On these bases, the existence of a glucocorticoid-mediated immunoregulatory circuit was proposed. It was also shown that increased levels of endogenous glucocorticoids exert protective effects during infections and other diseases with immune components. However, it was found in animal models and in humans that these effects can be blunted in several immune-linked diseases by defects at several levels, for example, by glucocorticoid resistance or by adrenal insufficiency. Evidence was later provided that the glucocorticoid-mediated immunoregulatory circuit can also be activated by cytokines produced not only as consequence of immune stimulation but also following psycho/sensorial and physical stimuli. Thus, this circuit can be integrated at brain levels and, besides stimulating the HPA axis, cytokines can also affect synaptic plasticity, most likely via a tripartite synapse, with astrocytes as neuro-immune cells acting as the third component.

Key messages: It is now well established that the glucocorticoid-mediated immunoregulatory circuit plays a central role in maintaining health. However, several variables can condition the efficacy of the effect of endogenous glucocorticoids. Furthermore, since cytokines and other immune products have many other neuroendocrine and metabolic effects, other neuroendocrine-immune circuits could simultaneously operate or become predominant during different pathologies. The consideration of these aspects might help to implement strategies to eventually decrease therapeutic doses of exogenous glucocorticoids.

Background: Establishing causal relationships is essential in biology and medicine. However, various notions of causality have been operationalized at different times in various fields of the life and health sciences. While this is expected from a history or sociology of science point of view, as different accounts may correspond to what is valued in terms of establishing causal relationships at different times as well as in different fields of biology and medicine, this may come as a surprise for a present-day actor in those fields. If, over time, causal accounts have not been fully dismissed, then they are likely to invite some form of, potentially salutary, explanatory pluralism.

Summary: In the decades following WWII, psychosomatic medicine could propose that psychological factors cause somatic diseases. But today, most medicine has to meet the standard of a randomized clinical trial before any causal relationship can be proposed. Instead, in biology, mechanisms seem to be the most-valued causal discourse to explain how phenomena of interest are brought about. Here, the focus will be on how psychoneuroimmunology, an interdisciplinary research field addressing interactions between the nervous system and immune system, and between behavior and health, has considered causal relationships between psychological factors and cancer.

Key messages: When it comes to causal explanations of links between psychological factors and cancer, psychoneuroimmunology is invited to consider the question of the directionality of these links as well as what and how factors causally contribute to cancer.