Bioprofiling of platelets in medicated patients with depression

Association between the platelet/high-density lipoprotein cholesterol ratio and depression: A cross-sectional analysis in United States adults

BACKGROUND

The primary objective of this study was to elucidate the relationship between the platelet/high-density lipoprotein cholesterol ratio (PHR) and the risk of depression in adults in the US.

METHODS

We conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2016. Depression was assessed using the PHQ-9 questionnaire. Weighted multivariable logistic regression models and restricted cubic spline (RCS) models were used to study the relationship between PHR and the risk of depression. Subgroup and interaction analyses were performed to further understand these associations.

RESULTS

A total of 21,454 participants were included in this study. After full adjustment, PHR was significantly positively correlated with depression (OR = 1.33, 95%CI: 1.03-1.73). When PHR was converted into a categorical variable based on quartiles (Q1-Q4), the highest quartile of PHR was associated with an increased risk of depression compared to the lowest reference group (OR = 1.22, 95%CI: 1.01-1.48). There was a linear dose-response relationship between PHR and the risk of depression (P-non-linear = 0.8038). The association remained significant in several subgroup analyses. However, the interaction test showed that none of the stratified variables were significant (all P for interaction >0.05).

LIMITATION

Using self-assessment scales and inability to assess causality.

CONCLUSION

This population-based cross-sectional study elucidated that PHR is significantly associated with an increased prevalence of depression in adults in the US.

Hyperactivity in the Hypothalamic-Pituitary-Adrenal Axis: An Invisible Killer for Anxiety and/or Depression in Coronary Artherosclerotic Heart Disease

The coexistence of anxiety or depression with coronary heart disease (CHD) is a significant clinical challenge in cardiovascular medicine. Recent studies have indicated that hypothalamic-pituitary-adrenal (HPA) axis activity could be a promising focus in understanding and addressing the development of treatments for comorbid CHD and anxiety or depression. The HPA axis helps to regulate the levels of inflammatory factors, thereby reducing oxidative stress damage, promoting platelet activation, and stabilizing gut microbiota, which enhance the survival and regeneration of neurons, endothelial cells, and other cell types, leading to neuroprotective and cardioprotective benefits. This review addresses the relevance of the HPA axis to the cardiovascular and nervous systems, as well as the latest research advancements regarding its mechanisms of action. The discussion includes a detailed function of the HPA axis in regulating the processes mentioned. Above all, it summarizes the therapeutic potential of HPA axis function as a biomarker for coronary atherosclerotic heart disease combined with anxiety or depression.

Stress-Induced Hypercoagulability: Insights from Epidemiological and Mechanistic Studies, and Clinical Integration

By integrating findings from comprehensive reviews, meta-analyses, and cutting-edge genetic studies, this article illuminates the significance of stress-induced hypercoagulability in clinical medicine. In particular, the findings from numerous prospective cohort studies indicate that stress and hemostatic factors of a hypercoagulable state are associated with increased incident risk and poor prognosis for atherosclerotic cardiovascular disease and venous thromboembolism. Mendelian randomization studies suggest that these associations are partially causal. The review synthesizes extensive research on the link between acute and chronic stress and hypercoagulability, outlining a potential pathway from stress to thrombosis risk. Consistent with the allostatic load concept, acute stress-induced hypercoagulability, initially adaptive, can turn maladaptive under chronic stress or excessive acute stress, leading to arterial or venous thrombotic events. Individuals with predisposing factors, including atherosclerosis, thrombophilia, or immobilization, may exhibit an increased risk of thrombotic disease during stress. Contextual sociodemographic characteristics, the stress experience, and coping resources additionally modulate the extent of stress-induced hypercoagulability. Research into the neuroendocrine, cellular, and molecular bases reveals how stress influences platelet activation coagulation and fibrinolysis. The activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis, along with vagal withdrawal, and the effects of catecholamines, cortisol, and vasopressin, are the central mechanisms involved. Hemoconcentration, inflammation, endothelial dysfunction, and thrombopoiesis additionally contribute to stress-induced hypercoagulability. Further research is needed to prove a causal link between chronic stress and hypercoagulability. This includes exploring its implications for the prevention and management of thrombotic diseases in stressed individuals, with a focus on developing effective psychosocial and pharmacological interventions.

Platelets bridging the gap between gut dysbiosis and neuroinflammation in stress-linked disorders: A narrative review

In this narrative review, we examine the association between gut dysbiosis, neuroinflammation, and stress-linked disorders, including depression, anxiety, and post-traumatic stress disorder (PTSD), and investigate whether tryptophan (TRP) metabolism and platelets play a role in this association. The mechanisms underlying the aetiology of stress-linked disorders are complex and not yet completely understood. However, a potential link between chronic inflammation and these disorders may potentially be found in TRP metabolism and platelets. By critically analysing existing literature on platelets, the gut microbiome, and stress-linked disorders, we hope to elicit the role of platelets in mediating the effects on serotonin (5-HT) levels and neuroinflammation. We have included studies specifically investigating platelets and TRP metabolism in relation to inflammation, neuroinflammation and neuropsychiatric disorders. Alteration in microbial composition due to stress could contribute to increased intestinal permeability, facilitating the translocation of microbial products, and triggering the release of pro-inflammatory cytokines. This causes platelets to become hyperactive and secrete 5-HT into the plasma. Increased levels of pro-inflammatory cytokines may also lead to increased permeability of the blood-brain barrier (BBB), allowing inflammatory mediators entry into the brain, affecting the balance of TRP metabolism products, such as 5-HT, kynurenic acid (KYNA), and quinolinic acid (QUIN). These alterations may contribute to neuroinflammation and possible neurological damage. Furthermore, platelets can cross the compromised BBB and interact with astrocytes and neurons, leading to the secretion of 5-HT and pro-inflammatory factors, exacerbating inflammatory conditions in the brain. The mechanisms underlying neuroinflammation resulting from peripheral inflammation are still unclear, but the connection between the brain and gut through the bloodstream could be significant. Identifying peripheral biomarkers and mechanisms in the plasma that reflect neuroinflammation may be important. This review serves as a foundation for further research on the association between the gut microbiome, blood microbiome, and neuropsychiatric disorders. The integration of these findings with protein and metabolite markers in the blood may expand our understanding of the subject.

The Role of Tryptophan Metabolites in Neuropsychiatric Disorders

In recent decades, neuropsychiatric disorders such as major depressive disorder, schizophrenia, bipolar, etc., have become a global health concern, causing various detrimental influences on patients. Tryptophan is an important amino acid that plays an indisputable role in several physiological processes, including neuronal function and immunity. Tryptophan’s metabolism process in the human body occurs using different pathways, including the kynurenine and serotonin pathways. Furthermore, other biologically active components, such as serotonin, melatonin, and niacin, are by-products of Tryptophan pathways. Current evidence suggests that a functional imbalance in the synthesis of Tryptophan metabolites causes the appearance of pathophysiologic mechanisms that leads to various neuropsychiatric diseases. This review summarizes the pharmacological influences of tryptophan and its metabolites on the development of neuropsychiatric disorders. In addition, tryptophan and its metabolites quantification following the neurotransmitters precursor are highlighted. Eventually, the efficiency of various biomarkers such as inflammatory, protein, electrophysiological, genetic, and proteomic biomarkers in the diagnosis/treatment of neuropsychiatric disorders was discussed to understand the biomarker application in the detection/treatment of various diseases.

Beyond Haemostasis and Thrombosis: Platelets in Depression and Its Co-Morbidities

Alongside their function in primary haemostasis and thrombo-inflammation, platelets are increasingly considered a bridge between mental, immunological and coagulation-related disorders. This review focuses on the link between platelets and the pathophysiology of major depressive disorder (MDD) and its most frequent comorbidities. Platelet- and neuron-shared proteins involved in MDD are functionally described. Platelet-related studies performed in the context of MDD, cardiovascular disease, and major neurodegenerative, neuropsychiatric and neurodevelopmental disorders are transversally presented from an epidemiological, genetic and functional point of view. To provide a complete scenario, we report the analysis of original data on the epidemiological link between platelets and depression symptoms suggesting moderating and interactive effects of sex on this association. Epidemiological and genetic studies discussed suggest that blood platelets might also be relevant biomarkers of MDD prediction and occurrence in the context of MDD comorbidities. Finally, this review has the ambition to formulate some directives and perspectives for future research on this topic.

Stress Enhances Proinflammatory Platelet Activity: the Impact of Acute and Chronic Mental Stress

The role of platelets in hemostasis and thrombosis has long been recognized, recently their contribution to immunological and inflammatory processes is emerging. Platelets could be the missing link between cardiovascular disease, chronic stress and depressive symptoms. Both physical and mental stressors cause platelet activation reflected by changes in platelet bioactivity and aggregation. Here we evaluate the proinflammatory platelet response to acute and chronic mental stress. In a prospective study design an acute mental stress test was administered to 55 healthy male participants once without and once in the presence of chronic mental stress. Blood was collected prior to and at three time points following an acute mental stress test (0, 30, 60 min). Platelet proinflammatory activation markers, were assessed using FACS analysis and aggregability was measured in response to ADP or epinephrine using PFA-100. A linear mixed model was used for analysis. Chronic mental stress lead to a significant increase in state anxiety (p < 0.001), depressive symptoms (p = 0.045) and perceived stress (p = 0.001). The factor “chronic mental stress” was significantly associated with increased numbers of CD63+ platelets (p = 0.009). The factor “acute mental stress” was associated with alterations in CD62P+ platelets (p < 0.001), CD63+ platelets (p = 0.011), PAC-1+ platelets (p < 0.001) as well as platelet leucocyte aggregates (p = 0.019). The recovery of CD62P function following the acute mental stress exposure was significantly impaired by chronic stress (p = 0.023). Aggregation was affected by chronic and acute mental stress. In conclusion, mental stress is linked to an increased and prolonged proinflammatory platelet bioactivity. This proinflammatory and immunomodulatory stimuli could help to explain the link between mental and somatic disorders.

Peripheral tryptophan, serotonin, kynurenine, and their metabolites in major depression: A case-control study

AIM

Tryptophan is the sole precursor of both peripherally and centrally produced serotonin and kynurenine. In depressed patients, tryptophan, serotonin, kynurenine, and their metabolite levels remain unclear. Therefore, peripheral tryptophan and metabolites of serotonin and kynurenine were investigated extensively in 173 patients suffering from a current major depressive episode (MDE) and compared to 214 healthy controls (HC).

METHODS

Fasting plasma levels of 11 peripheral metabolites were quantified: tryptophan, serotonin pathway (serotonin, its precursor 5-hydroxytryptophan and its metabolite 5-hydroxyindoleacetic acid), and kynurenine pathway (kynurenine and six of its metabolites: anthranilic acid, kynurenic acid, nicotinamide, picolinic acid, xanthurenic acid, and 3-hydroxyanthranilic acid).

RESULTS

Sixty (34.7%) patients were antidepressant-drug free. Tryptophan levels did not differ between MDE patients and HC. Serotonin and its precursor (5-hydroxytryptophan) levels were lower in MDE patients than in HC, whereas, its metabolite (5-hydroxyindoleacetic acid) levels were within the standard range. Kynurenine and four of its metabolites (kynurenic acid, nicotinamide, picolinic acid, and xanthurenic acid) were lower in MDE patients.

CONCLUSION

Whilst the results of this study demonstrate an association between the metabolites studied and depression, conclusions about causality cannot be made. This study uses the largest ever sample of MDE patients, with an extensive assessment of peripheral tryptophan metabolism in plasma. These findings provide new insights into the peripheral signature of MDE. The reasons for these changes should be further investigated. These results might suggest new antidepressant therapeutic strategies.

Personalized Epigenome Remodeling Under Biochemical and Psychological Changes During Long-Term Isolation Environment

It has been reported that several aspects of human health could be disturbed during a long-term isolated environment (for instance, the Mars-500 mission), including psychiatric disorders, circadian disruption, temporal dynamics of gut microbiota, immune responses, and physical-activity-related neuromuscular performance. Nevertheless, the mechanisms underlying these disturbances and the interactions among different aspects of human adaptation to extreme environments remain to be elucidated. Epigenetic features, like DNA methylation, might be a linking mechanism that explains the involvement of environmental factors between the human genome and the outcome of health. We conducted an exploration of personalized longitudinal DNA methylation patterns of the peripheral whole blood cells, profiling six subjects across six sampling points in the Mars-500 mission. Specifically, we developed a Personalized Epigenetic-Phenotype Synchronization Analysis (PeSa) algorithm to explore glucose- and mood-state-synchronized DNA methylation sites, focusing on finding the dynamic associations between epigenetic patterns and phenotypes in each individual, and exploring the underling epigenetic connections between glucose and mood-state disturbance. Results showed that DMPs (differentially methylated-probes) were significantly enriched in pathways related to glucose metabolism (Type II diabetes mellitus pathway), mood state (Long-term depression) and circadian rhythm (Circadian entrainment pathway) during the mission. Furthermore, our data revealed individualized glucose-synchronized and mood-state-synchronized DNA methylation sites, and PTPRN2 was found to be associated with both glucose and mood state disturbances across all six subjects. Our findings suggest that personalized phenotype-synchronized epigenetic features could reflect the effects on the human body, including the disturbances of glucose and mood-states. The association analysis of DNA methylation and phenotypes, like the PeSa analysis, could provide new possibilities in understanding the intrinsic relationship between phenotypic changes of the human body adapting to long-term isolation environmental factors.

Serum Proteomics in African American Female Patients With Irritable Bowel Syndrome: An Exploratory Study

Background

Sex and subtype differences within patients with irritable bowel syndrome (IBS) complicate the understanding of disorder pathogenesis and hinder the design of efficacious, therapeutic interventions.

Objectives

The aims of this study were to harness the power of shotgun proteomic analysis, identify circulating proteins that differentiate African American female patients with IBS from healthy controls (HC), and gain biological insight on symptomatology.

Methods

Serum proteome analysis was performed upon a cohort of overweight, African American female participants with constipation predominant IBS symptoms (n = 5) and HC (n = 5), matched on age, sex, years of education, body mass index, and 11 physiological markers. Tandem mass tags for multiplexed proteomic analysis were performed, incorporating reverse-phase liquid chromatography and liquid chromatography-tandem mass spectrometry.

Results

Participants with IBS did not differ from HC in demographics, clinical characteristics, or initial proteomic analysis. Nested case control analysis of six samples (IBS: n = 3, HC: n = 3), hierarchically clustered into two main groups, with 12 out of 1,317 proteins significantly different in levels of expression: TGFβ1, PF4V1, PF4, APP, MMP9, PPBP, CTGF, SRGN, THBS1, WRN, LTBP1 (Isoform 3), and IGLV5-48. Top associations of identified proteins in DAVID and STRING resources (upregulated in HC vs. IBS) involve platelet alpha granule lumen, platelet activation/degranulation, extracellular region, and secretion by cell.

Discussion

Differentially expressed proteins between participants with IBS and HC involving platelet-related associations prompt inquiry as to differences in serotonergic signaling, inflammatory or immunomodulatory mechanisms underlying IBS symptomatology. Although preliminary and requiring validation in larger cohorts, these findings bear relevance to understanding pathogenic processes of IBS and biological effects of the disorder.

Effects of long-term administration of Lactobacillus reuteri DSM-17938 on circulating levels of 5-HT and BDNF in adults with functional constipation

Accumulated evidence shows that some probiotic strains ameliorate functional constipation (FC) via the modulation of specific gastrointestinal peptide pathways. The aims of this study were to investigate: (1) the effects of long-term administration of Lactobacillus reuteri (LR) DSM 17938 on the serum levels of serotonin (5-HT) and brain-derived neurotrophic factor (BDNF); (2) the possible link between 5-HT, BDNF, and specific constipation-related symptoms; (3) whether genetic variability at the 5-HTT gene-linked polymorphic region (5-HTTLPR) and BDNF Val66Met loci could be associated with serum 5-HT and BDNF variations. LR DSM 17938 was administered to 56 FC patients for 105 days in a randomised, double-blind manner. The fasting blood samples were collected during the randomisation visit (V₁), at day 15 (induction period, V₂), day 60 (intermediate evaluation, V₃), and day 105 (V₄) and the Constipaq questionnaire (the sum of Constipation Scoring System (CSS) and patient assessment constipation quality of life (PAC-QoL)) was administered. A group of healthy subjects was enrolled as controls (HC). At V1, the mean serum 5-HT level in the whole patient group was significantly higher (P=0.027) than in HC subjects, while serum BDNF did not. At the end of probiotic administration (V4), 5-HT and BDNF levels were significantly lower than the initial values (V1) (P=0.008 and P=0.015, respectively). 5-HT and BDNF serum concentration were significantly associated (r=0.355; P=0.007). Neither 5-HT nor BDNF serum levels correlated with the CSS item scores and with the PAC-QoL. Lastly, the regression analysis demonstrated that the presence of the S allele of the 5-HTTLPR accounted for the reduction in the 5-HT concentration at V4. In conclusion, the long-term administration of LR DSM 17938 demonstrated that such a probiotic strain could improve FC by affecting 5-HT and BDNF serum concentrations.

Variables affecting the potential efficacy of PRP in providing chronic pain relief

Although chronic pain affects about 1% of the US population, it remains largely resistant to treatment. Despite great variability in pain outcomes, the application of autologous platelet-rich plasma (PRP) has become increasingly popular in attempts to reduce chronic pain. The variability in PRP efficacy raises the question of whether PRP actually has an analgesic capacity, and if so, can that capacity be made consistent and maximized. The best explanation for the variability in PRP analgesic efficacy is the failure during PRP preparation and application to take into account variables that can increase or eliminate its analgesic capabilities. This suggests that if the variables are reduced and controlled, a PRP preparation and application protocol can be developed leading to PRP inducing reliable, complete, and long-term pain relief. The goal of this study was to examine some of the variables that influence platelets and see how they might be controlled to increase the analgesic potential of PRP. Among the variables examined are the physiological status of the patient, methods used to prepare PRP, and methods of PRP application. The goal of modifying these variables is to minimize platelet serotonin content, maximize platelet content of factors that reduce inflammation and pain, while maintaining their bioactivity, maximize platelet capacity to aggregate at injury sites, induce rapid and simultaneous release of their contents, and optimize PRP application protocols. It is concluded that controlling some or many of these variables will lead to PRP that induces reliable, maximum, and long-term relief of chronic pain.

Chemokines in depression in health and in inflammatory illness: a systematic review and meta-analysis

Inflammatory illness is associated with depression. Preclinical work has shown that chemokines are linked with peripheral-central crosstalk and may be important in mediating depressive behaviours. We sought to establish what evidence exists that differences in blood or cerebrospinal fluid chemokine concentration discriminate between individuals with depression and those without. Following PRISMA guidelines, we systematically searched Embase, PsycINFO and Medline databases. We included participants with physical illness for subgroup analysis, and excluded participants with comorbid psychiatric diagnoses. Seventy-three studies met the inclusion criteria for the meta-analysis. Individuals with depression had higher levels of blood CXCL4 and CXCL7 and lower levels of blood CCL4. Sensitivity analysis of studies with only physically healthy participants identified higher blood levels of CCL2, CCL3, CCL11, CXCL7 and CXCL8 and lower blood levels of CCL4. All other chemokines examined did not reveal significant differences (blood CCL5, CCL7, CXCL9, CXCL10 and cerebrospinal fluid CXCL8 and CXCL10). Analysis of the clinical utility of the effect size of plasma CXCL8 in healthy individuals found a negative predictive value 93.5%, given the population prevalence of depression of 10%. Overall, our meta-analysis finds evidence linking abnormalities of blood chemokines with depression in humans. Furthermore, we have demonstrated the possibility of classifying individuals with depression based on their inflammatory biomarker profile. Future research should explore putative mechanisms underlying this association, attempt to replicate existing findings in larger populations and aim to develop new diagnostic and therapeutic strategies.

Consensus paper of the WFSBP Task Force on Genetics: Genetics, epigenetics and gene expression markers of major depressive disorder and antidepressant response

Major depressive disorder (MDD) is a heritable disease with a heavy personal and socio-economic burden. Antidepressants of different classes are prescribed to treat MDD, but reliable and reproducible markers of efficacy are not available for clinical use. Further complicating treatment, the diagnosis of MDD is not guided by objective criteria, resulting in the risk of under- or overtreatment. A number of markers of MDD and antidepressant response have been investigated at the genetic, epigenetic, gene expression and protein levels. Polymorphisms in genes involved in antidepressant metabolism (cytochrome P450 isoenzymes), antidepressant transport (ABCB1), glucocorticoid signalling (FKBP5) and serotonin neurotransmission (SLC6A4 and HTR2A) were among those included in the first pharmacogenetic assays that have been tested for clinical applicability. The results of these investigations were encouraging when examining patient-outcome improvement. Furthermore, a nine-serum biomarker panel (including BDNF, cortisol and soluble TNF-α receptor type II) showed good sensitivity and specificity in differentiating between MDD and healthy controls. These first diagnostic and response-predictive tests for MDD provided a source of optimism for future clinical applications. However, such findings should be considered very carefully because their benefit/cost ratio and clinical indications were not clearly demonstrated. Future tests may include combinations of different types of biomarkers and be specific for MDD subtypes or pathological dimensions.