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Molecular Psychiatry Aug 2023The serotonin hypothesis of depression is still influential. We aimed to synthesise and evaluate evidence on whether depression is associated with lowered serotonin... (Meta-Analysis)
Meta-Analysis
The serotonin hypothesis of depression is still influential. We aimed to synthesise and evaluate evidence on whether depression is associated with lowered serotonin concentration or activity in a systematic umbrella review of the principal relevant areas of research. PubMed, EMBASE and PsycINFO were searched using terms appropriate to each area of research, from their inception until December 2020. Systematic reviews, meta-analyses and large data-set analyses in the following areas were identified: serotonin and serotonin metabolite, 5-HIAA, concentrations in body fluids; serotonin 5-HT receptor binding; serotonin transporter (SERT) levels measured by imaging or at post-mortem; tryptophan depletion studies; SERT gene associations and SERT gene-environment interactions. Studies of depression associated with physical conditions and specific subtypes of depression (e.g. bipolar depression) were excluded. Two independent reviewers extracted the data and assessed the quality of included studies using the AMSTAR-2, an adapted AMSTAR-2, or the STREGA for a large genetic study. The certainty of study results was assessed using a modified version of the GRADE. We did not synthesise results of individual meta-analyses because they included overlapping studies. The review was registered with PROSPERO (CRD42020207203). 17 studies were included: 12 systematic reviews and meta-analyses, 1 collaborative meta-analysis, 1 meta-analysis of large cohort studies, 1 systematic review and narrative synthesis, 1 genetic association study and 1 umbrella review. Quality of reviews was variable with some genetic studies of high quality. Two meta-analyses of overlapping studies examining the serotonin metabolite, 5-HIAA, showed no association with depression (largest n = 1002). One meta-analysis of cohort studies of plasma serotonin showed no relationship with depression, and evidence that lowered serotonin concentration was associated with antidepressant use (n = 1869). Two meta-analyses of overlapping studies examining the 5-HT receptor (largest n = 561), and three meta-analyses of overlapping studies examining SERT binding (largest n = 1845) showed weak and inconsistent evidence of reduced binding in some areas, which would be consistent with increased synaptic availability of serotonin in people with depression, if this was the original, causal abnormaly. However, effects of prior antidepressant use were not reliably excluded. One meta-analysis of tryptophan depletion studies found no effect in most healthy volunteers (n = 566), but weak evidence of an effect in those with a family history of depression (n = 75). Another systematic review (n = 342) and a sample of ten subsequent studies (n = 407) found no effect in volunteers. No systematic review of tryptophan depletion studies has been performed since 2007. The two largest and highest quality studies of the SERT gene, one genetic association study (n = 115,257) and one collaborative meta-analysis (n = 43,165), revealed no evidence of an association with depression, or of an interaction between genotype, stress and depression. The main areas of serotonin research provide no consistent evidence of there being an association between serotonin and depression, and no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations. Some evidence was consistent with the possibility that long-term antidepressant use reduces serotonin concentration.
Topics: Humans; Depression; Serotonin; Receptor, Serotonin, 5-HT1A; Tryptophan; Hydroxyindoleacetic Acid; Antidepressive Agents; Serotonin Plasma Membrane Transport Proteins
PubMed: 35854107
DOI: 10.1038/s41380-022-01661-0 -
Nutrients Aug 2023Human milk oligosaccharides (HMOs) are a major component of human milk. They are associated with multiple health benefits and are manufactured on a large scale for their... (Review)
Review
Human milk oligosaccharides (HMOs) are a major component of human milk. They are associated with multiple health benefits and are manufactured on a large scale for their addition to different food products. In this systematic review, we evaluate the health outcomes of published clinical trials involving the supplementation of manufactured HMOs. We screened the PubMed database and Cochrane Library, identifying 26 relevant clinical trials and five publications describing follow-up studies. The clinical trials varied in study populations, including healthy term infants, infants with medical indications, children, and adults. They tested eight different HMO structures individually or as blends in varying doses. All trials included safety and tolerance assessments, and some also assessed growth, stool characteristics, infections, gut microbiome composition, microbial metabolites, and biomarkers. The studies consistently found that HMO supplementation was safe and well tolerated. Infant studies reported a shift in outcomes towards those observed in breastfed infants, including stool characteristics, gut microbiome composition, and intestinal immune markers. Beneficial gut health and immune system effects have also been observed in other populations following HMO supplementation. Further clinical trials are needed to substantiate the effects of HMO supplementation on human health and to understand their structure and dose dependency.
Topics: Adult; Child; Infant; Female; Humans; Milk, Human; Breast Feeding; Commerce; Oligosaccharides; Dietary Supplements
PubMed: 37630811
DOI: 10.3390/nu15163622 -
EClinicalMedicine Aug 2023Intranasal esketamine has received regulatory approvals for the treatment of depression. Recently a large trial of repeated dose racemic ketamine also demonstrated...
BACKGROUND
Intranasal esketamine has received regulatory approvals for the treatment of depression. Recently a large trial of repeated dose racemic ketamine also demonstrated efficacy in severe depression. However, uncertainties remain regarding comparative efficacy, dosage, and the time course of response.
METHODS
In this systematic review and meta-analysis, we searched Embase, Medline, Pubmed, PsycINFO, and CENTRAL up to April 13, 2023, for randomised controlled trials (RCTs) investigating ketamine for depression. Two investigators independently assessed study eligibility and risk of bias and extracted the data on depression severity scores, response and remission rates, and all-cause dropouts. Multivariable mixed-effects meta-regressions incorporated drug formulation (racemic (Rac) or esketamine (Esket)) and dose (Low or High) as covariates. Treatment effects were assessed: immediately following the first dose, during further repeated dosing, and follow-up after the final dose of a treatment course. This study is registered with PROSPERO (CRD42021221157).
FINDINGS
The systematic review identified 687 articles, of which 49 RCTs were eligible for analysis, comprising 3299 participants. Standardised mean differences (95% confidence intervals) immediately following the first/single treatment were moderate-high for all conditions (Rac-High: -0.73, -0.91 to -0.56; Esket-High: -0.48, -0.75 to -0.20; Rac-Low: -0.33, -0.54 to -0.12; Esket-Low: -0.55, -0.87 to -0.24). Ongoing effects during repeated dosing were significantly greater than the control for Rac-High (-0.61; -1.02 to -0.20) and Rac-Low (-0.55, -1.09 to -0.00), but not Esket-Low (-0.15, -0.49 to 0.19) or Esket-High (-0.22, -0.54 to 0.10). At follow-up effects remained significant for racemic ketamine (-0.65; -1.23 to -0.07) but not esketamine (-0.33; -0.96 to 0.31). All-cause dropout was similar between experiment and control conditions for both formulations combined (Odds Ratio = 1.18, 0.85-1.64). Overall heterogeneity varied from 5.7% to 87.6.
INTERPRETATION
Our findings suggested that effect sizes for depression severity, as well as response and remission rates, were numerically greater for racemic ketamine than esketamine. Higher doses were more effective than low doses. Differences were evident in initial effects, ongoing treatment, and lasting effects after the final dose.
FUNDING
None.
PubMed: 37593223
DOI: 10.1016/j.eclinm.2023.102127 -
Journal of Agricultural and Food... Aug 2023Berries are rich in (poly)phenols, and these compounds may be beneficial to human health. Estimating berry consumption through self-reported questionnaires has been... (Review)
Review
Berries are rich in (poly)phenols, and these compounds may be beneficial to human health. Estimating berry consumption through self-reported questionnaires has been challenging due to compliance issues and a lack of precision. Estimation via food-derived biomarkers in biofluids was proposed as a complementary alternative. We aimed to review and update the existing evidence on biomarkers of intake for six different types of berries. A systematic literature search was performed to update a previous systematic review on PubMed, Web of Science, and Scopus from January 2020 until December 2022. Out of 42 papers, only 18 studies were eligible. A multimetabolite panel is suggested for blueberry and cranberry intake. Proposed biomarkers for blueberries include hippuric acid and malvidin glycosides. For cranberries, suggested biomarkers are glycosides of peonidin and cyanidin together with sulfate and glucuronide conjugates of phenyl-γ-valerolactone derivatives. No new metabolite candidates have been found for raspberries, strawberries, blackcurrants, and blackberries. Further studies are encouraged to validate these multimetabolite panels for improving the estimation of berry consumption.
Topics: Humans; Fruit; Fragaria; Rubus; Blueberry Plants; Glycosides; Vaccinium macrocarpon
PubMed: 37499164
DOI: 10.1021/acs.jafc.3c01142 -
Environmental Pollution (Barking, Essex... Sep 2023Phthalates are chemicals widely used in plastic-based consumer products, and human exposure is universal. They are classified as endocrine disruptors, and specific... (Meta-Analysis)
Meta-Analysis Review
Phthalates are chemicals widely used in plastic-based consumer products, and human exposure is universal. They are classified as endocrine disruptors, and specific phthalate metabolites have been associated with an increased risk of cardiometabolic diseases. The aim of this study was to assess the association between phthalate exposure and the metabolic syndrome in the general population. A comprehensive literature search was performed in four databases (Web of Science, Medline, PubMed, and Scopus). We included all the observational studies that evaluate the association between phthalate metabolites and the metabolic syndrome available until January 31st, 2023. Pooled Odds Ratios (OR) and their 95% confidence intervals were calculated by using the inverse-variance weighted method. Nine cross-sectional studies and 25,365 participants aged from 12 to 80 were included. Comparing extreme categories of phthalate exposure, the pooled ORs for the metabolic syndrome were: 1.08 (95% CI, 1.02-1.16, I = 28%) for low molecular weight phthalates, and 1.11 (95% CI, 1.07-1.16, I = 7%) for high molecular weight phthalates. For individual phthalate metabolites, the pooled ORs that achieved statistical significance were: 1.13 (95% CI, 1.00-1.27, I = 24%) for MiBP; 1.89 (95% CI, 1.17-3.07, I = 15%) for MMP in men; 1.12 (95% CI, 1.00-1.25, I = 22%) for MCOP; 1.09 (95% CI, 0.99-1.20, I = 0%) for MCPP; 1.16 (95% CI, 1.05-1.28, I = 6%) for MBzP; and 1.16 (95% CI, 1.09-1.24, I = 14%) for DEHP (including ΣDEHP and its metabolites). In conclusion, both low molecular weight and high molecular weight phthalates were associated with an 8 and 11% higher prevalence of the MetS, respectively. The exposure to six specific phthalate metabolites was associated with a higher prevalence of the MetS.
Topics: Male; Humans; Metabolic Syndrome; Environmental Pollutants; Cross-Sectional Studies; Phthalic Acids; Plastics; Environmental Exposure
PubMed: 37328121
DOI: 10.1016/j.envpol.2023.121957 -
Nutrients Nov 2023Multiple studies have indicated that distinct metabolites are involved in the occurrence and development of osteopenia (ON) and osteoporosis (OP); however, these... (Meta-Analysis)
Meta-Analysis Review
Multiple studies have indicated that distinct metabolites are involved in the occurrence and development of osteopenia (ON) and osteoporosis (OP); however, these metabolites in OP and ON have not yet been classified and standardized. This systematic review and meta-analysis included 21 articles aiming to investigate the distinct metabolites in patients with ON and OP. The quality of the included articles was generally high; seventeen studies had >7 stars, and the remaining four received 6 stars. This systematic review showed that three metabolites (phosphatidylcholine (PC) (lipid metabolites), galactose (carbohydrate metabolites), and succinic acid (other metabolites)) increased, four (glycylglycine (gly-gly), cystine (amino acids), sphingomyelin (SM) (lipid metabolites) and glucose (carbohydrate metabolites)) decreased, and five (glutamine, hydroxyproline, taurine (amino acids), lysophosphatidylcholine (LPC) (lipid metabolites), and lactate (other metabolites)) had conflicting directions in OP/ON. The results of the meta-analysis show that gly-gly (MD = -0.77, 95%CI -1.43 to -0.11, = 0.02) and cystine (MD = -5.52, 95%CI -7.35 to -3.68, < 0.00001) decreased in the OP group compared with the healthy control group. Moreover, LPC (MD = 1.48, 95%CI 0.11 to 2.86, = 0.03) increased in the OP group compared with the healthy control group. These results indicate that distinct metabolites were associated with ON and OP, which could be considered a predictor for OP.
Topics: Humans; Cystine; Osteoporosis; Bone Diseases, Metabolic; Amino Acids; Lysophosphatidylcholines; Carbohydrates
PubMed: 38068753
DOI: 10.3390/nu15234895 -
Life Sciences Nov 2023A diverse and stable microbiota promotes a healthy state, nevertheless, an imbalance in gut or oral bacterial composition, called dysbiosis, can cause gastrointestinal... (Review)
Review
A diverse and stable microbiota promotes a healthy state, nevertheless, an imbalance in gut or oral bacterial composition, called dysbiosis, can cause gastrointestinal disorders, systemic inflammatory states and oxidative stress, among others. Recently, gut and oral dysbiosis has been linked to Alzheimer's disease (AD), which is considered the most common form of dementia and a public health priority due to its high prevalence and incidence. The aim of this review is to highlight the implications of gut and oral microbiota in the neuroinflammation characteristic of AD pathology and the subsequent cognitive impairment. It is a systematic review of the current literature obtained by searching the PubMed, Web of Science and Scopus databases. The characteristic intestinal dysbiosis in AD patients leads to increased permeability of the intestinal barrier and activates immune cells in the central nervous system due to translocation of microbiota-derived metabolites and/or bacteria into the circulation leading to increased neuroinflammation and neuronal loss, thus generating the cognitive impairment characteristic of AD. The presence in the central nervous system of Porphyromonas gingivalis can cause an increased neuroinflammation and beta-amyloid peptide accumulation.
Topics: Humans; Alzheimer Disease; Gastrointestinal Microbiome; Neuroinflammatory Diseases; Dysbiosis; Microbiota; Inflammation; Bacteria; Brain
PubMed: 37793482
DOI: 10.1016/j.lfs.2023.122132 -
Metabolites Sep 2023Autoimmune diseases, characterized by the immune system's loss of self-tolerance, lack definitive diagnostic tests, necessitating the search for reliable biomarkers.... (Review)
Review
Autoimmune diseases, characterized by the immune system's loss of self-tolerance, lack definitive diagnostic tests, necessitating the search for reliable biomarkers. This systematic review aims to identify common metabolite changes across multiple autoimmune diseases. Following PRISMA guidelines, we conducted a systematic literature review by searching MEDLINE, ScienceDirect, Google Scholar, PubMed, and Scopus (Elsevier) using keywords "Metabolomics", "Autoimmune diseases", and "Metabolic changes". Articles published in English up to March 2023 were included without a specific start date filter. Among 257 studies searched, 88 full-text articles met the inclusion criteria. The included articles were categorized based on analyzed biological fluids: 33 on serum, 21 on plasma, 15 on feces, 7 on urine, and 12 on other biological fluids. Each study presented different metabolites with indications of up-regulation or down-regulation when available. The current study's findings suggest that amino acid metabolism may serve as a diagnostic biomarker for autoimmune diseases, particularly in systemic lupus erythematosus (SLE), multiple sclerosis (MS), and Crohn's disease (CD). While other metabolic alterations were reported, it implies that autoimmune disorders trigger multi-metabolite changes rather than singular alterations. These shifts could be consequential outcomes of autoimmune disorders, representing a more complex interplay. Further studies are needed to validate the metabolomics findings associated with autoimmune diseases.
PubMed: 37755267
DOI: 10.3390/metabo13090987 -
Biomedicines Dec 2023Antipsychotics are an important pharmacotherapy option for the treatment of many mental illnesses. Unfortunately, selecting antipsychotics is often a trial-and-error... (Review)
Review
Antipsychotics are an important pharmacotherapy option for the treatment of many mental illnesses. Unfortunately, selecting antipsychotics is often a trial-and-error process due to a lack of understanding as to which medications an individual patient will find most effective and best tolerated. Metabolomics, or the study of small molecules in a biosample, is an increasingly used omics platform that has the potential to identify biomarkers for medication efficacy and toxicity. This systematic review was conducted to identify metabolites and metabolomic pathways associated with antipsychotic use in humans. Ultimately, 42 studies were identified for inclusion in this review, with all but three studies being performed in blood sources such as plasma or serum. A total of 14 metabolite classes and 12 lipid classes were assessed across studies. Although the studies were highly heterogeneous in approach and mixed in their findings, increases in phosphatidylcholines, decreases in carboxylic acids, and decreases in acylcarnitines were most consistently noted as perturbed in patients exposed to antipsychotics. Furthermore, for the targeted metabolomic and lipidomic studies, seven metabolites and three lipid species had findings that were replicated. The most consistent finding for targeted studies was an identification of a decrease in aspartate with antipsychotic treatment. Studies varied in depth of detail provided for their study participants and in study design. For example, in some cases, there was a lack of detail on specific antipsychotics used or concomitant medications, and the depth of detail on sample handling and analysis varied widely. The conclusions here demonstrate that there is a large foundation of metabolomic work with antipsychotics that requires more complete reporting so that an objective synthesis such as a meta-analysis can take place. This will then allow for validation and clinical application of the most robust findings to move the field forward. Future studies should be carefully controlled to take advantage of the sensitivity of metabolomics while limiting potential confounders that may result from participant heterogeneity and varied analysis approaches.
PubMed: 38137517
DOI: 10.3390/biomedicines11123295 -
Ageing Research Reviews Dec 2023Alterations in nitric oxide (NO) synthesis have been reported in Alzheimer's disease and vascular dementia. However, as the measurement of NO in biological samples is... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Alterations in nitric oxide (NO) synthesis have been reported in Alzheimer's disease and vascular dementia. However, as the measurement of NO in biological samples is analytically challenging, alternative, stable circulatory biomarkers of NO synthesis may be useful to unravel new pathophysiological mechanisms and treatment targets in dementia.
METHODS
We conducted a systematic review and meta-analysis of the circulating concentrations of arginine metabolites linked to NO synthesis, arginine, citrulline, asymmetric (ADMA) and symmetric (SDMA) dimethylarginine, and ornithine, in Alzheimer's disease and vascular dementia. We searched for relevant studies in PubMed, Scopus, and Web of Science from inception to the 31st of May 2023. The JBI checklist and GRADE were used to assess the risk of bias and the certainty of evidence, respectively.
RESULTS
In 14 selected studies, there were no significant between-group differences in arginine and ornithine concentrations. By contrast, compared to controls, patients with dementia had significantly higher ADMA (standard mean difference, SMD=0.62, 95% CI 0.06-1.19, p = 0.029), SDMA (SMD=0.70, 95% CI 0.34-1.35, p<0.001), and citrulline concentrations (SMD=0.50, 95% CI 0.08-0.91, p = 0.018). In subgroup analysis, the effect size was significantly associated with treatment with cholinesterase inhibitors and/or antipsychotics for ADMA, and underlying disorder (Alzheimer's disease), study continent, and analytical method for citrulline.
CONCLUSION
Alterations in ADMA, SDMA, and citrulline, biomarkers of NO synthesis, may be useful to investigate the pathophysiology of different forms of dementia and identify novel therapeutic strategies. (PROSPERO registration number: CRD42023439528).
Topics: Humans; Alzheimer Disease; Dementia, Vascular; Citrulline; Arginine; Biomarkers; Ornithine
PubMed: 38007048
DOI: 10.1016/j.arr.2023.102139