The association between serum homocysteine and depression: A systematic review and meta-analysis of observational studies

The association between weight-waist-adjustment index and serum folate in US adults: NHANES 2013 to 2018

Obesity is closely related to human metabolism and a variety of diseases. The association between weight-waist-adjustment index (WWI, a new index for obesity) and serum folate has not been sufficiently explored. Data from the National Health and Nutrition Examination Survey (2013-2018) was used to explore the correlation between WWI and serum folate. 12,757 adult participants were included in our study. In order to discern the relationship, we conducted weighted multiple linear regression analysis, generalized weighted smooth curve fitting and threshold effect analyses. Additionally, we executed subgroup analysis and interaction tests. There was a negative correlation between WWI and serum folate. In subgroup analysis, the relationship between WWI and serum folate were more pronounced among females, the elderly (65-80 years), nonsmokers, and those with hypertension or stroke. Furthermore, a nonlinear association between WWI and serum folate was found using smooth curve fitting (likelihood ratio = 0.014), with a threshold identified at WWI of 7.42. We discovered a stronger association between WWI and serum folate than other obesity markers including body mass index and waist circumference. Our study could help obese people predict serum folate and manage their nutrition well.

Comprehensive review of thrombophilia: pathophysiology, prevalence, risk factors, and molecular diagnosis

Thrombophilia, characterized by an imbalance between fibrinolysis and coagulation leading to inappropriate blood clotting, is a significant medical condition. The CDC has designated it as an underdiagnosed, serious, and potentially preventable disorder, contributing to an estimated 600,000-900,000 cases and 100,000 deaths annually in the United States. These figures surpass the combined annual mortality of AIDS, breast cancer, and motor vehicle accidents. The pathogenesis of thrombophilia involves complex interactions between genetic predispositions, such as mutations in Factor V Leiden, Factor II, MTHFR, and Serpine-1, and environmental factors, including unhealthy lifestyles, prolonged hospitalization, obesity, and cancer. Prevalence of specific genetic mutations varies across populations. Additional risk factors include age, family history, and pregnancy, with recent attention to increased susceptibility in SARS-CoV-2 infection. While molecular diagnostic techniques are available, there remains a need for robust, cost-effective, and accurate screening methods for large populations. This systematic review provides an updated overview of thrombophilia, encompassing pathophysiology, epidemiology, genetic and environmental risk factors, coagulation cascade, population-specific mutation prevalence, and diagnostic approaches. By synthesizing clinical and molecular evidence, this review aims to guide researchers, hematologists, and clinicians in the diagnosis and management of thrombophilia.

Homocysteine and Multiple Health Outcomes: An Outcome-Wide Umbrella Review of Meta-analyses and Mendelian Randomization Studies

Elevated levels of homocysteine (Hcy) are associated with various health outcomes. We aimed to systematically assess the credibility and certainty of evidence of associations of Hcy and Hcy-lowering therapies with various health outcomes. We retrieved observational meta-analyses examining the associations between Hcy and health outcomes, interventional meta-analyses investigating health outcomes related to Hcy-lowering treatments, and Mendelian randomization (MR) studies exploring the causal associations of Hcy with health outcomes to perform an umbrella review. A total of 135 observational meta-analyses, 106 MR studies, and 26 interventional meta-analyses were included. Among observational studies, 10 associations of diseases/outcomes were classified as highly suggestive; only 1 outcome (digestive tract cancer) was supported by convincing evidence (class I; odd ratio = 1.27, 95% confidence interval = 1.16, 1.40; P = 6.79 × 10-7; I2 = 0, 95% prediction interval excluding null, >1000 cases; P > 0.1 for tests of both small-study effects and excess significance bias). In MR studies, 5 outcomes associated with Hcy presented robust evidence (P < 0.01, power >80%). Among 25 outcomes explored by both observational meta-analyses and MR studies, 7 had consistent results, indicating that elevated Hcy is causally associated with an increased risk of these outcomes. The 3 types of studies collectively suggested that the association of stroke with Hcy was supported by observational studies, causally by MR studies, and further validated by intervention meta-analyses showing that Hcy-lowering with folic acid significantly reduced risk of stroke. For dementia and colorectal cancer, Hcy was significantly associated in meta-analyses of observational studies and folic acid decreased disease risks in interventional meta-analyses. The current umbrella review indicates that convincing evidence for a definitive role of Hcy exposure solely exists in the context of digestive tract cancer excluding bias; however, Hcy may not be causal for this disease. All the 3 types of studies collectively support that Hcy is a key causal risk factor, and Hcy-lowering (specifically with folic acid) may serve as an effective intervention for stroke. This trial was registered at PROSPERO as CRD42024541335.

Association of low vitamin B12 levels with depressive and schizophrenia spectrum disorders in child and adolescent psychiatric inpatients

Folate and vitamin B12 are associated with neurodevelopment and neurotransmitter synthesis and insufficiencies of these nutrients could be linked to psychiatric disorders in children and adolescents. To assess serum levels of folate and B12 in child and adolescent psychiatric inpatients and examine possible links between these levels and different psychiatric disorders. Child and adolescent psychiatric inpatients admitted in a general hospital during a 3-year period were included for analysis. Folate and B12 levels were measured when the subjects were admitted. Psychiatric diagnoses were made following DSM-5 criteria and grouped into categories. Logistic regression analysis was used to study the effects of socio-demographic variables as well as folate and B12 levels, insufficiencies and deficits as possible predictors of outcome (psychiatric diagnostic category). 729 inpatients (60.6% female, mean age: 15.1 ± 2 years) were included. A total of 42.9% presented insufficient folate levels and 19.4% insufficient B12 levels. Insufficient B12 levels were associated with depressive disorders in the multivariate model (OR = 0.82, p = 0.002) as was female sex (OR = 1.65, p = 0.007). Moreover, low vitamin B12 levels were linked to schizophrenia spectrum disorders (SSD, OR = 0.9982, p = 0.024). In contrast, higher folate (OR = 1.15, p < 0.001) and vitamin B12 levels (1.0024, p = 0.002) as well as female sex (OR = 7.86, p < 0.001) were associated with eating disorders. Insufficient or low B12 levels could help predict depressive and SSD respectively in child and adolescent psychiatric inpatients. Further study could help us better understand the impact of this insufficiency during the neurodevelopmental period and the potential benefits of nutritional interventions.

Association of plasma homocysteine with cognitive impairment in patients with Parkinson's disease

Background

Elevated plasma homocysteine (Hcy) has been reported as a risk factor for cognitive impairment in the general population. However, there are conflicting results regarding the relationship between Hcy and cognitive impairment across various cognitive domains in Parkinson's disease (PD).

Objective

This study aims to explore the association between plasma Hcy levels, cognitive impairment, and dysfunction in various cognitive domains among PD patients with and without mild cognitive impairment (MCI).

Methods

A total of 101 PD patients underwent plasma Hcy measurement, comprising 50 PD-MCI patients and 51 patients with normal cognition (PD-NC). A battery of neuropsychological tests was administered to assess different cognitive domains. Adjusted generalized linear models were used to assess the correlations between Hcy levels and cognitive functions.

Results

As anticipated, PD-MCI patients demonstrated a significant decline in cognitive function across all five cognitive domains (memory, executive function, attention/working memory, language, and visuospatial function). Elevated plasma Hcy levels (≥ 10 μmol/L) were associated with a higher odds of PD-MCI, even within the normal range of Hcy levels (< 15 μmol/L). After adjusting for confounding factors, a negative correlation was observed between plasma Hcy levels and the performance on specific cognitive tests evaluating executive functions in PD, such as the Stroop Color-Word Test-C (β = -1.123, 95% CI = -1.845 ∼-0.401, p = 0.0023).

Conclusion

This study underscores a significant link between plasma Hcy levels and PD-MCI, particularly concerning executive dysfunction, even within the normal range of Hcy levels (< 15 μmol/L).

Longitudinal association of homocysteine with depressive and anxiety symptoms among urban adults: healthy aging in neighborhoods of diversity across the life span study

Longitudinal associations of homocysteine (HCY) with depressive symptoms scores among urban adults remain under-studied, especially across sex, race and levels of anxiety. We examined longitudinal associations of homocysteine (HCY) with depressive symptoms scores among urban adults, before and after stratifying by sex, race and anxiety level, using data from 1460 Healthy Aging in Neighborhoods of Diversity across the Lifespan Study (HANDLS) participants aged 30-64 y at v1 (2004-2009), followed across 3 visits up to 2017. In addition to LnHcyv1, we used group-based trajectory models predicting z-transformed likelihood of greater LnHcy with age (Hcytraj). Total and domain-specific depression symptoms were scored using Center for Epidemiologic Studies Depression (CES-D) scale. Mixed-effects linear regression models and Cox proportional hazards models were utilized. A positive association was found between baseline LnHcyv1 and CES-D total scores in reduced socio-demographic- adjusted Model 1 (β (standard error [SE]) = + 2.337 (0.902), P = 0.010), a relationship slightly attenuated in fully adjusted Model 2 (Model 1 adjusting for lifestyle and health factors) with a β (SE) = + 1.825 (0.883), P = 0.039. Individuals with lower anxiety levels experienced faster CES-D domain 2 score annualized increase over time (interpersonal problems) with higher LnHcyv1 (β (SE) = 0.041 (0.018), P = 0.024). Hcytraj was linked to incident elevated depressive symptoms (CES-D total score ≥16) overall (fully adjusted model: HR = 1.09, 95% CI: 1.03-1.14, P = 0.001), particularly among women and those living in poverty. Baseline and "high trajectory" of LnHcy were positively associated with depressive symptoms and elevated depressive symptom incidence, in a sex-, race-, poverty status- and anxiety-level specific manner.

Association between sleep duration and the risk of hyperhomocysteinemia among adults in the United States: National Health and Nutrition Examination Survey, 2005-2006

The study aimed to discuss the association between sleep duration and the risk of hyperhomocysteinemia (Hhcy). This cross-sectional study included 4173 adults (≥ 20 years) from the National Health and Nutrition Examination Survey 2005-2006. According to their sleep duration, participants were divided into five subgroups. Multivariate logistic regression analysis models and restrictive cubic spline regressions were used to explore the association between sleep duration and the risk of Hhcy. Compared with the participants who sleep 7 h, sleep deprivation (≤ 5 h) increased the risk of Hhcy, odds ratio (OR) 1.68 (95% confidence interval (CI) 1.06-2.68); Excessive sleep (≥ 9 h) also increased the risk of Hhcy, OR 1.86 (95% CI 1.09-3.14) after adjusting for a series of confounding factors in the entire population. The risk of Hhcy was distributed in a U-shape with sleep duration. Similar results were demonstrated in obese populations. The association between sleep duration and the risk of Hhcy is U-shaped. Both sleep deprivation and excessive sleep can increase the risk of Hhcy.

Hyperhomocysteinemia and its effect on ageing and language functions - HEAL study

Hyperhomocysteinemia or high levels (> 15 µmol/L) of homocysteine (Hcy)in the blood has been suggested to affect the brain through vascular and neurodegenerative pathways and potentially impact cognition. The current study aims to explore the association of high homocysteine with cognition and brain volume changes in a cohort of middle and old agedr adults. The study recruited 1296 participants aged ≥ 45 years from Tata Longitudinal Study of Ageing (TLSA), an ongoing cohort study. The participants underwent detailed cognitive assessments using Addenbrooke's Cognitive Examination-III (ACE-III) and Computerized Assessment of Adult Information Processing (COGNITO) neuropsychological battery and MR imaging using a 3T scanner. The participants were classified based on the median homocysteine level (16.89 µmol/L) into low Hcy (≤ median) and high Hcy (> median) groups. When adjusted for age, gender, years of education, vitamin B12, folate and dyslipidaemia, Generalised Linear Model (GLM) found a significant association of high Hcy with vocabulary task [β (95% CI) - 1.354 (- 2.655, - 0.052); p = 0.041]. Significant associations was also obtained between cerebral white matter volume and high Hcy [β (95% CI) - 5617.182 (- 11062.762, - 173.602); p = 0.043]. The results suggest that people with high Hcy levels performed poorer in cognitive tasks related to language domain and had lesser cerebral white matter volume. This indicates that homocysteine might have a profound impact on brain structure as well as function.

Biomarkers Associated with Depression Improvement in Veterans with Gulf War Illness Using the Low-Glutamate Diet

Gulf War Illness (GWI) is a chronic multi-symptom neurological disorder affecting veterans of the Gulf War that is commonly comorbid with depression. A secondary data analysis was conducted to examine serum homocysteine and inflammatory cytokines (IFN-γ, IL-6, IL-1β, TNF-α) as potential biomarkers of depression improvement among veterans with GWI after a one-month dietary intervention aimed at reducing excitotoxicity and increasing micronutrients. Analyses, including multiple linear and logistic regression, were conducted in R studio. Dietary adherence was estimated using a specialized excitotoxin food frequency questionnaire (FFQ), and depression was measured using the Center for Epidemiologic Studies Depression (CES-D) scale. After one month on the diet, 52% of participants reported a significant decrease in depression (p < 0.01). Greater dietary adherence (FFQ) was associated with increased likelihood of depression improvement; OR (95% CI) = 1.06 (1.01, 1.11), (p = 0.02). Reduced homocysteine was associated with depression improvement after adjusting for FFQ change (β = 2.58, p = 0.04), and serum folate and vitamin B12 were not mediators of this association. Reduction in IFN-γ was marginally associated with likelihood of depression improvement (OR (95% CI) = 1.11 (0.00, 1.42), (p = 0.06)), after adjustment for potential confounders. Findings suggest that homocysteine, and possibly IFN-γ, may serve as biomarkers for depression improvement in GWI. Larger trials are needed to replicate this work.

Higher homocysteine and fibrinogen are associated with early-onset post-stroke depression in patients with acute ischemic stroke

Background

Post-stroke depression (PSD) is a well-established psychiatric complication following stroke. Nevertheless, the relationship between early-onset PSD and homocysteine (Hcy) or fibrinogen remains uncertain.

Methods

Acute ischemic stroke (AIS) patients who met the established criteria were enrolled in this study. Early-onset PSD was diagnosed two weeks after the stroke. The severity of depressive symptoms was assessed by the Hamilton Depression Scale-17 items (HAMD-17), with patients scored ≥7 assigned to the early-onset PSD group. Spearman rank correlation analysis was employed to evaluate the associations between Hcy, fibrinogen, and HAMD scores across all patients. Logistic regression analysis was conducted to investigate the relationship between Hcy, fibrinogen, and early-onset PSD. Receiver operating characteristic curve (ROC) analysis was ASSDalso performed to detect the predictive ability of Hcy and fibrinogen for early-onset PSD.

Results

Among the 380 recruited patients, a total of 106 (27.89%) patients were diagnosed with early-onset PSD. The univariate analysis suggested that patients in the PSD group had a higher admission National Institutes of Health Stroke Scale (NIHSS) score, modified Rankin Scale score (mRS), Hcy, and fibrinogen levels than patients in the non-PSD group (P<0.05). The logistic regression model indicated that Hcy (odds ratio [OR], 1.344; 95% confidence interval [CI] 1.209-1.494, P<0.001) and fibrinogen (OR, 1.57 6; 95% CI 1.302-1.985, P<0.001) were independently related to early-onset PSD. Area under curve (AUC) of Hcy, fibrinogen, and Hcy combined fibrinogen to predict early-onset PSD was 0.754, 0.698, and 0.803, respectively.

Conclusion

This study indicates that Hcy and fibrinogen may be independent risk factors for early-onset PSD and can be used as predictive indicators for early-onset PSD.

Homocysteine levels in first-episode patients with psychiatric disorders

A high homocysteine (Hcy) level is a risk factor for schizophrenia, depression, and bipolar disorder. However, the role of hyperhomocysteinemia as either an independent factor or an auxiliary contributor to specific psychiatric symptoms or disorders remains unclear. This study aimed to examine Hcy levels in first-episode inpatients with psychotic symptoms and various psychiatric diseases to elucidate the association between Hcy levels and psychiatric disorders. This study enrolled 191 patients (aged 18-40 years) with psychiatric disorders. Seventy-five patients were diagnosed with schizophrenia, 48 with acute and transient psychotic disorders, 36 with manic episodes with psychosis, 32 with major depressive episodes with psychosis, and 56 healthy controls. Serum Hcy levels were measured using the enzyme cycle method. A Hcy concentration level of > 15 μmol/L was defined as hyperhomocysteinemia. Hcy levels were significantly higher in first-episode patients with psychiatric disorders compared to healthy controls (5.99 ± 3.60 vs. 19.78 ± 16.61 vs. 15.50 ± 9.08 vs. 20.00 ± 11.33 vs. 16.22 ± 12.06, F = 12.778, P < 0.001). Hcy levels were significantly higher in males with schizophrenia, acute and transient psychotic disorder, and major depressive disorder but not in mania [schizophrenia, (t = -4.727, P < 0.001); acute and transient psychotic disorders, (t = -3.389, P = 0.001); major depressive episode with psychosis, (t = -3.796, P < 0.001); manic episodes with psychosis, (t = -1.684, P = 0.101)]. However, serum Hcy levels were not significantly different among the psychiatric disorder groups (F = 0.139, P = 0.968). Multivariate linear regression showed that males had an increased risk for homocysteinemia. (95% CI = 8.192-15.370, P < 0.001). These results suggest that first-episode patients with psychiatric disorders have higher Hcy levels than in the general population, and men are at greater risk for psychiatric disorders. In conclusion, elevated Hcy levels may contribute to the pathogenesis of first-episode patients with psychotic symptoms.

Alteration of gut microbiota in post-stroke depression patients with Helicobacter pylori infection

BACKGROUND

Several studies have identified an association between the gut microbiome and post-stroke depression(PSD), and Helicobacter pylori(H. pylori) infection cause significant alterations in the composition of the gastrointestinal microbiome. However, evidence regarding the role of the H. pylori infection in promoting PSD is still lacking. Here, we conducted a retrospective study to explore risk factors associated with PSD.

METHODS

Patients with cerebral infarction were consecutively enrolled from December 2021 to October 2022. The diagnosis of PSD is based on the DSM-V criteria, and the Hamilton Depression Rating Scale(HAMD) was used to identify patients with PSD. White matter lesions were evaluated using magnetic resonance imaging(MRI) and H. pylori infection was detected by 13C-urea breath test. Further, 16S rRNA gene sequencing was used to evaluate the changes in gut microbiota composition of fecal samples from PSD patients. The concentration of short-chain fatty acids(SCFAs) was determined by gas chromatography-mass spectrometry(GC-MS).

RESULTS

Multivariate regression analysis showed that deep white matter lesions(DWMLs) [odds ratio(OR) 3.382, 95% confidence interval(CI) 1.756-6.512; P = 0.001] and H. pylori infection(OR 2.186, 95% CI 1.149-4.159; P = 0.017) were the independent risk factors for PSD. Patients with H. pylori infection had more severe depressive symptoms than patients without infection. Intestinal microbiota was significantly different between H. pylori-positive PSD[H. pylori(+)] patients and H. pylori-negative PSD[H. pylori (-)] patients. Fecal SCFAs concentrations were significantly reduced in the H. pylori(+) group compared to the negative ones.

CONCLUSION

DWMLs and H. pylori infection may play important roles in the development of PSD. H. pylori infection is likely to be involved in the pathogenesis of PSD by altering the intestinal flora.

Plasma levels of hydrogen sulfide and homocysteine correlate with the efficacy of antidepressant agents and serve as potential diagnostic and therapeutic markers

OBJECTIVE

Hydrogen sulfide (H2S) is associated with depressive-like behavior in rodents. We undertook cross-sectional and longitudinal analyses of plasma levels of H2S and its substrate homocysteine (Hcy) in depression and assessed the association of both parameters with psychopathology and cognitive function.

METHODS

Forty-one patients suffering from depression (PSDs) and 48 healthy volunteers were recruited. PSDs were treated for 8 weeks. Analyzable data were collected from all participants for assessment of their psychopathology and cognitive function. Plasma was collected for determination of levels of H2S and Hcy, and data were correlated to determine their potential as plasma biomarkers.

RESULTS

Cross-sectional analyses revealed PSDs to have a low plasma H2S level and high Hcy level. Longitudinal analyses revealed that 8 weeks of treatment reversed the changes in plasma levels of H2S and Hcy in PSDs. Plasma levels of H2S and Hcy were associated with psychopathology and cognitive function in depression. The area under the receiver operating characteristic curve (AUC) for a combination of plasma levels of H2S and Hcy and expression of the TNF gene (i.e., H2S-Hcy-TNF) was 0.848 for diagnosing depression and 0.977 for predicting the efficacy of antidepressant agents.

CONCLUSION

Plasma levels of H2S and Hcy reflect changes in psychopathology and cognitive function in depression and H2S-Hcy-TNF has the potential to diagnose depression and predict the efficacy of antidepressant medications.

Untargeted Plasma Metabolomic Profiling in Patients with Depressive Disorders: A Preliminary Study

Depressive disorder is a multifactorial disease that is based on dysfunctions in mental and biological processes. The search for biomarkers can improve its diagnosis, personalize therapy, and lead to a deep understanding of the biochemical processes underlying depression. The purpose of this work was a metabolomic analysis of blood serum to classify patients with depressive disorders and healthy individuals using Compound Discoverer software. Using high-resolution mass spectrometry, blood plasma samples from 60 people were analyzed, of which 30 were included in a comparison group (healthy donors), and 30 were patients with a depressive episode (F32.11) and recurrent depressive disorder (F33.11). Differences between patient and control groups were identified using the built-in utilities in Compound Discoverer software. Compounds were identified by their accurate mass and fragment patterns using the mzCloud database and tentatively identified by their exact mass using the ChemSpider search engine and the KEGG, ChEBI, FDA UNII-NLM, Human Metabolome and LipidMAPS databases. We identified 18 metabolites that could divide patients with depressive disorders from healthy donors. Of these, only two compounds were tentatively identified using the mzCloud database (betaine and piperine) based on their fragmentation spectra. For three compounds ((4S,5S,8S,10R)-4,5,8-trihydroxy-10-methyl-3,4,5,8,9,10-hexahydro-2H-oxecin-2-one, (2E,4E)-N-(2-hydroxy-2-methylpropyl)-2,4-tetradecadienamide and 17α-methyl-androstan-3-hydroxyimine-17β-ol), matches were found in the mzCloud database but with low score, which could not serve as reliable evidence of their structure. Another 13 compounds were identified by their exact mass in the ChemSpider database, 9 (g-butyrobetaine, 6-diazonio-5-oxo-L-norleucine, 11-aminoundecanoic acid, methyl N-acetyl-2-diazonionorleucinate, glycyl-glycyl-argininal, dilaurylmethylamine, 12-ketodeoxycholic acid, dicetylamine, 1-linoleoyl-2-hydroxy-sn-glycero-3-PC) had only molecular formulas proposed, and 4 were unidentified. Thus, the use of Compound Discoverer software alone was not sufficient to identify all revealed metabolites. Nevertheless, the combination of the found metabolites made it possible to divide patients with depressive disorders from healthy donors.

Association between suicide attempts and anemia in late-life depression inpatients

BACKGROUND

Anemia is strongly associated with late-life depression (LLD), however, few studies have investigated the relationship between anemia and suicide attempts in LLD patients. It is still challenging to predict suicide risk in patients with depression. Therefore, there is growing interest in potential biomarkers of depressive disorders and suicidal behavior, which may play a significant role in the early diagnosis and treatment of depression. This study aimed to compare serum ferritin, folate, vitamin B12, and erythrocyte parameter levels in patients with LLD with those in healthy older adults, and the relationship between serum ferritin, folate, vitamin B12, and suicide attempts in patients.

METHODS

Serum ferritin, folate, vitamin B12, and erythrocyte parameter levels were measured in 66 hospitalized LLD patients (30 without suicide attempt, 36 with suicide attempt) and 47 healthy individuals. All participants were surveyed for basic conditions and suicide attempts, and depression was assessed in LLD patients.

RESULTS

Serum ferritin, folate, vitamin B12, red blood cell count, hemoglobin, hematocrit, mean platelet volume and plateletcrit levels were significantly lower in LLD patients compared with healthy older adults (P < 0.05). Further analysis of the relationship between serum ferritin, folate, and vitamin B12 levels and LLD patients' suicide attempts and showed a significant negative association between serum folate and vitamin B12 and suicide attempts (P < 0.05).

CONCLUSIONS

Serum ferritin, folate, vitamin B12, red blood cell count, hemoglobin, hematocrit, mean platelet volume and plateletcrit levels were significantly lower in LLD patients than in healthy older adults. In addition, reduced serum folate and vitamin B12 levels in patients may have some effect on suicide attempts. More mechanistic studies are needed to further explain this association.

The SLC6A15-SLC6A20 Neutral Amino Acid Transporter Subfamily: Functions, Diseases, and Their Therapeutic Relevance

The neutral amino acid transporter subfamily that consists of six members, consecutively SLC6A15-SLC620, also called orphan transporters, represents membrane, sodium-dependent symporter proteins that belong to the family of solute carrier 6 (SLC6). Primarily, they mediate the transport of neutral amino acids from the extracellular milieu toward cell or storage vesicles utilizing an electric membrane potential as the driving force. Orphan transporters are widely distributed throughout the body, covering many systems; for instance, the central nervous, renal, or intestinal system, supplying cells into molecules used in biochemical, signaling, and building pathways afterward. They are responsible for intestinal absorption and renal reabsorption of amino acids. In the central nervous system, orphan transporters constitute a significant medium for the provision of neurotransmitter precursors. Diseases related with aforementioned transporters highlight their significance; SLC6A19 mutations are associated with metabolic Hartnup disorder, whereas altered expression of SLC6A15 has been associated with a depression/stress-related disorders. Mutations of SLC6A18-SLCA20 cause iminoglycinuria and/or hyperglycinuria. SLC6A18-SLC6A20 to reach the cellular membrane require an ancillary unit ACE2 that is a molecular target for the spike protein of the SARS-CoV-2 virus. SLC6A19 has been proposed as a molecular target for the treatment of metabolic disorders resembling gastric surgery bypass. Inhibition of SLC6A15 appears to have a promising outcome in the treatment of psychiatric disorders. SLC6A19 and SLC6A20 have been suggested as potential targets in the treatment of COVID-19. In this review, we gathered recent advances on orphan transporters, their structure, functions, related disorders, and diseases, and in particular their relevance as therapeutic targets. SIGNIFICANCE STATEMENT: The following review systematizes current knowledge about the SLC6A15-SLCA20 neutral amino acid transporter subfamily and their therapeutic relevance in the treatment of different diseases.

Mechanisms associated with post-stroke depression and pharmacologic therapy

Stroke is one of the most common cerebrovascular diseases, which is the cause of long-term mental illness and physical disability, Post-stroke depression (PSD) is the most common neuropsychiatric complication after stroke, and its mechanisms are characterized by complexity, plurality, and diversity, which seriously affects the quality of survival and prognosis of patients. Studies have focused on and recognized neurotransmitter-based mechanisms and selective serotonin-reuptake inhibitors (SSRIs) can be used to treat PSD. Neuroinflammation, neuroendocrinology, neurotrophic factors, and the site of the stroke lesion may affect neurotransmitters. Thus the mechanisms of PSD have been increasingly studied. Pharmacological treatment mainly includes SSRIs, noradrenergic and specific serotonergic antidepressant (NaSSA), anti-inflammatory drugs, vitamin D, ect, which have been confirmed to have better efficacy by clinical studies. Currently, there is an increasing number of studies related to the mechanisms of PSD. However, the mechanisms and pharmacologic treatment of PSD is still unclear. In the future, in-depth research on the mechanisms and treatment of PSD is needed to provide a reference for the prevention and treatment of clinical PSD.

Association of serum homocysteine, folate, and vitamin B12 and mood following the Swank and Wahls elimination dietary interventions in relapsing-remitting multiple sclerosis: Secondary analysis of the WAVES trial

BACKGROUND

Depression and anxiety are common psychiatric comorbidities among people with multiple sclerosis (MS). Emerging data suggest abnormal serum homocysteine, vitamin B12, and folate levels in people with MS, which are related to a range of neurological disorders, including mood and mental illnesses. Evidence suggests that dietary interventions could affect mood disorders via several pathways. This study aimed to evaluate the impact of the low-saturated fat (Swank) and modified Paleolithic elimination (Wahls) diets, along with a supplement regimen, on mood as assessed by Hospital Anxiety and Depression Scale (HADS), and Mental Health Inventory (MHI). The secondary objective was to identify changes in serum levels of homocysteine, folate, and vitamin B12 and the association and mediation effects between their changes and HADS and MHI scores and their subscales among people with relapsing-remitting MS (RRMS).

METHODS

In a previously conducted randomized parallel-arm trial, participants with RRMS (n = 77) were randomly allocated to either the Swank or Wahls diets at baseline and followed for 24 weeks. Blood was drawn at four study visits spaced 12 weeks apart: (1) run-in, (2) baseline, (3) 12 weeks, and (4) 24 weeks. Serum vitamin B12, folate, and homocysteine were analyzed. HADS and MHI questionnaires were also completed by participants at the four study visits to assess symptoms of depression and anxiety, behavioral control and positive affect respectively.

RESULTS

Significant improvement in severity of depression (HADS-D) and anxiety (HADS-A) symptoms, MHI total, and MHI subscores were seen at 12 and 24 weeks in each diet group. Further, a significant within-group reduction in serum homocysteine and a significant increase in serum vitamin B12 level were observed in both groups at 12 and 24 weeks compared to corresponding baseline values (p ≤ 0.05 for all). All participants exceeded the analytical maximum threshold for folate of 20 nmol/L at 12 and 24 weeks. Changes in serum levels of homocysteine and vitamin B12 were not associated with and did not mediate changes in HADS depression, anxiety, MHI total and four subscales scores (p > 0.05).

CONCLUSION

Participants on both Swank and Wahls dietary interventions, including folate and vitamin B12 supplements, showed significant improvement in mood. However, the favorable effects of both diets on mood were not associated with or mediated by the effect of the diets on serum levels of homocysteine, folate, and vitamin B12 (p > 0.05).

Unlocking the Secrets: Exploring the Biochemical Correlates of Suicidal Thoughts and Behaviors in Adults with Autism Spectrum Conditions

Involving 1 million people a year, suicide represents one of the major topics of psychiatric research. Despite the focus in recent years on neurobiological underpinnings, understanding and predicting suicide remains a challenge. Many sociodemographical risk factors and prognostic markers have been proposed but they have poor predictive accuracy. Biomarkers can provide essential information acting as predictive indicators, providing proof of treatment response and proposing potential targets while offering more assurance than psychological measures. In this framework, the aim of this study is to open the way in this field and evaluate the correlation between blood levels of serotonin, brain derived neurotrophic factor, tryptophan and its metabolites, IL-6 and homocysteine levels and suicidality. Blood samples were taken from 24 adults with autism, their first-degree relatives, and 24 controls. Biochemical parameters were measured with enzyme-linked immunosorbent assays. Suicidality was measured through selected items of the MOODS-SR. Here we confirm the link between suicidality and autism and provide more evidence regarding the association of suicidality with increased homocysteine (0.278) and IL-6 (0.487) levels and decreased tryptophan (-0.132) and kynurenic acid (-0.253) ones. Our results suggest a possible transnosographic association between these biochemical parameters and increased suicide risk.

General Strategy for Specific Fluorescence Imaging of Homocysteine in Living Cells and In Vivo

The aberrantly changed level of homocysteine (Hcy) triggers a variety of pathological symptoms and subsequently Hcy-related diseases. Direct and selective visualization of Hcy in biological systems is pivotal to understanding the pathological functions of Hcy at the molecular level. Herein, a general strategy was developed for the specific fluorescence imaging of Hcy through the combination of dual-binding sites and the introduction of a nitro group at the 6-position of the 7-diethylaminocoumarin fluorophore. Also, a series of novel fluorescent probes were exploited for monitoring Hcy with excellent selectivity, high sensitivity, and far-red/near-infrared fluorescence emission. Furthermore, fluorescence imaging of endogenous Hcy dynamics in living cells and in vivo was achieved, providing direct and solid evidence for the increasement of endogenous Hcy in type 2 diabetes mellitus and Alzheimer's disease. This research will greatly advance the development and understanding of the molecular nexus between the Hcy metabolism cascade and the root causes of diseases related to Hcy.

The associations of dietary folate and serum folate with lipid profiles: findings from the national health and nutrition examination survey 2011-2016

BACKGROUND

Folate is considered to be related to lipid metabolism. With the increasing numbers of folic acid fortification nations, the associations of dietary folate and serum folate with lipid profiles deserve more attention and are worth further study.

METHODS

US adults aged ≥ 20 years from the National Health and Nutrition Examination Survey (NHANES) were evaluated. Participants taking folic acid supplements were excluded. The multivariate linear regression model and smooth curve fitting were applied to assess the associations. The segmented regression model was employed to examine the threshold effect of nonlinear relationships.

RESULTS

Our cross-sectional study included 3706 participants in total. There was a negative relationship between serum folate (log transformed) and triglycerides (β = -0.223, 95% CI: -0.337, -0.110) and low-density lipoprotein cholesterol (LDL-C) (β = -0.152, 95% CI: -0.296, -0.007) and a positive relationship between serum folate (log transformed) and high-density lipoprotein cholesterol (HDL-C) (β = 0.090, 95% CI: 0.033,0.146). There was a negative association between dietary folate (log transformed) and total cholesterol (TC) (β = -0.299, 95% CI: -0.465, -0.134) and LDL-C (β = -0.266, 95% CI: -0.409, -0.123). A nonlinear relationship was found between dietary folate (log transformed) and HDL-C. Threshold effect analysis showed that the inflection point was 377.57 ug. Within the inflection point, the β-coefficient of HDL-C was 0.105 (95% CI: 0.018, 0.192); beyond the inflection point, there was no relationship (β = -0.067, 95% CI: -0.162, 0.028).

CONCLUSIONS

Optimal dietary folate and high serum folate were associated with favorable lipid profiles. Dietary folate, in the recommended 300-400 ug/d, had a beneficial effect on improving lipid profiles.

Efficacy of B-vitamins and vitamin D therapy in improving depressive and anxiety disorders: a systematic review of randomized controlled trials

OBJECTIVES

This systematic review aimed to evaluate the efficacy of B vitamins and vitamin D therapy in improving the standard treatment of depression and anxiety disorders. We also aimed to gather the evidence supporting the recommendations for supplementation in clinical practice.

METHODS

Performed between March 2020 and September 2021, the main inclusion criteria were randomized controlled trials (RCTs), with patients ≥ 18 years old, both sexes, fulfilling target diagnoses of major depressive disorder (MDD), generalized anxiety disorder (GAD), or mild to severe depressive and anxiety symptoms. In addition, the RCTs were included if the scales to assess the severity of the symptoms were standardized rating scales in psychiatric. Trials that reported diagnoses of schizophrenia, perinatal depression, bipolar depression, sleep disorders, eating disorders, cancer, and multiple sclerosis in association with any of the mentioned diagnoses were excluded.

RESULTS

We identified 20 RCTs that matched all eligibility criteria, totaling 2,256 subjects, diagnosed with MDD, GAD, and depressive or anxiety symptoms. Supplementation with folic acid or L-methylfolate, B1, B12 or methylcobalamin, and vitamin D (in different doses and study duration) significantly decreased depression score scales by increasing response to standard pharmacological treatment or as monotherapy, including partial or complete remission. As for anxiety symptoms, the availability of results is limited to adjuvant vitamin D therapy.

DISCUSSION

B vitamins and vitamin D associated with other compounds also showed significant results, so the improvement in symptoms cannot be attributed strictly to those. Our results suggest that intervention with B vitamins and/or vitamin D may be an effective and well-tolerated adjuvant strategy for improving the symptoms of depression and anxiety, according to the patient's clinical status and nutritional biomarkers.

Dietary factors, risk of developing depression, and severity of its symptoms in older adults-A narrative review of current knowledge

Depression is one of the most common diseases in the older population. Difficulties in recognizing its etiology and recurrence make depression a major challenge for health care professionals. The risk of developing depression is influenced by many factors, including lifestyle and diet. Research studies have shown a relationship between the consumption of specific macro- and microelements and depression. However, so far, no nutritional recommendations on how to reduce the risk of the disease and its relapses in older adults have been developed. This review outlines research results of conducted studies and focuses on both basic and potentially promising elements of diet, such as proteins, carbohydrates, fats, dietary fiber, vitamins (D, E, C, and B), and microelements such as magnesium, zinc, selenium, or iron.

Association of homocysteine and polymorphism of methylenetetrahydrofolate reductase with early-onset post stroke depression

Background

Homocysteine (Hcy) has been indicated to be involved in pathophysiology of post stroke depression (PSD). There is a lack of research to study the relationship between Hcy metabolism genes and PSD. Our study aims to investigate the relationship among Hcy metabolism genes, Hcy, and early-onset PSD.

Materials and methods

We recruited 212 patients with stroke and collected their peripheral blood sample, clinical data, and laboratory test on admission. 12 single nucleotide polymorphisms (SNPs) in methylenetetrahydrofolate reductase (MTHFR), methionine synthase reductase (MTRR), and methionine synthase (MTR) genes were genotyped by high-resolution melt analysis. PSD was diagnosed by DSM-V at 2 weeks after stroke. Binary logistic regression and haplotype analysis were used to examine the association between Hcy metabolism genes and PSD. Mediation analysis was performed to clarify whether the SNPs exerted their effect on PSD by affecting the Hcy level.

Results

81 patients were diagnosed with PSD, and the incidence rate was 38.2%. Hcy level in PSD group was significantly higher than it in non-PSD group (p = 0.019). MTHFR rs1801133 AA genotype an A allele were associated with an elevated risk of PSD after adjustment for some confounding factors (OR = 4.021, 95% CI: 1.459∼11.080, p = 0.007 for AA genotype; OR = 1.808, 95% CI: 1.172∼2.788, p = 0.007 for A allele). Furthermore, the effect of MTHFR rs1801133 AA genotype on PSD was mediated by Hcy (OR = 1.569, 95% CI: 0.013∼3.350, p < 0.05).

Conclusion

MTHFR rs1801133 and Hcy were associated with PSD, and MTHFR rs1801133 may exert an effect on PSD via mediating Hcy level. This offers a new perspective for treating PSD and understanding the mechanism of PSD.

Case report: A late-onset cobalamin C defect first presenting as a depression in a teenager

Background: The cobalamin C (cblC) defect, a common inborn disorder of cobalamin metabolism due to a genetic mutation in MMACHC, can cause combined methylmalonic acid and homocysteine accumulation in blood, urine, or both. In this article, a late-onset case was reported, and the patient first presented with depression identified with the MMACHC gene. We summarized the clinical features of the cblC defect, the relationship between genotype and phenotype, and the clinical experience concerning the diagnosis and treatment of the cblC defect.

Case presentation: Initially presented with depression, the 16-year-old female patient showed progressive abnormal gait and bilateral lower limb weakness after 3 months. Blood routine examination suggested severe hyperhomocysteinemia, and screening for urine organic acids found elevated methylmalonic acid. Family gene sequencing showed mutations detected in MMACHC. She had a compound heterozygous mutation, while the c.271dupA (p.R91Kfs∗14) was only detected in her father and the c.482 G>A (p.R161Q) was only detected in her mother. Hence, she was diagnosed with a cblC defect and treated with B vitamin supplements. The muscle strength of both lower limbs improved notably.

Conclusion: This case indicated that depression could be a presenting sign of cblC-type methylmalonic aciduria and homocysteinemia, and enhanced the genotype–phenotype relationship of the cblC defect, which will contribute to further understanding of this emerging disease.

Intrinsic Capacity Declines with Elevated Homocysteine in Community-Dwelling Chinese Older Adults

Purpose

Intrinsic capacity (IC) reflects the overall health status of older adults and has great public health significance. But few studies described the related biomarkers for IC. The aim of this study was to investigate the association between homocysteine (Hcy) and IC in older adults.

Participants and Methods

This cross-sectional study included 1927 community-dwelling Chinese older adults aged 60–98 years from May 2020 to December 2020. Data were collected through interviews, physical examinations, and laboratory tests. IC involved five domains of cognition, locomotion, sensory, vitality, and psychology evaluated by the Mini-cog scale, 4-m walk test, self-reported visual and hearing conditions, MNA-SF scale, and GDS-4 scale, respectively. The score of each domain dichotomized as 0 (normal) and 1 (impaired) was added together to an IC total score. Low IC was defined as a score of 3–5, and high IC as 0–2. Hcy was measured by a two-reagent enzymatic assay. A restricted cubic spline regression model was used to explore the non-linear relationship between Hcy and low IC.

Results

Hcy was higher in the low IC group than in the high IC group. Restricted cubic spline analysis revealed a J-shaped nonlinear association between Hcy and low IC. The risk of IC decline was slowly decreased until 8.53 µmol/L of Hcy (OR=0.753, 95% CI=0.520–1.091, P=0.132), and increased with elevations of per 5 µmol/L Hcy afterwards (OR=1.176, 95% CI=1.059–1.327, P=0.005). Among the five domains of IC, Hcy had ORs of 1.116 (1.009–1.247) for cognition impairment, 1.167 (1.055–1.305) for vitality, and 1.160 (1.034–1.303) for psychology per 5 µmol/L increase in Hcy above the change point. Additional sensitivity analysis also demonstrated the nonlinear association between Hcy and low IC.

Conclusion

Hcy had a J-shaped association with low IC. Higher Hcy (Hcy ≥8.53µmol/L) might provide clinical implications for early identifying the risk of low IC.

Maternal Mental Health in Late Pregnancy and Longitudinal Changes in Postpartum Serum Vitamin B-12, Homocysteine, and Milk B-12 Concentration Among Brazilian Women

Background

Little is known regarding the association between mental health distress during pregnancy and postpartum maternal serum biomarkers of vitamin B-12 status and milk B-12 concentration.

Objective

To evaluate the association between depressive and anxiety symptoms in the third trimester of pregnancy and changes in postpartum serum B-12, homocysteine, and B-12 milk concentration.

Methods

A total of 101 women (18–40 years) were studied in a prospective cohort with data at the third trimester of pregnancy (baseline) and three postpartum time-points (TPs): 2–8 days (TP1), 28–50 days (TP2), and 88-119 days (TP3) postpartum. B-12 concentrations in milk were measured by competitive chemiluminescent enzyme immunoassay at TP1, TP2, and TP3. Serum B-12 and homocysteine concentrations were evaluated at baseline, TP1, TP2, and TP3 by chemiluminescent immunoassays. Depressive and anxiety symptoms were measured with the Edinburgh Postnatal Depression Scale and the State-Trait Anxiety Inventory at baseline. Spearman's correlation test and multiple linear mixed-effect models were performed.

Results

The prevalence of depressive and anxiety state symptoms was 35.6 and 39.6% at baseline. High prevalence of low milk B-12 concentration (<310 pmol/L) were observed at TP1 (53.2%), TP2 (71.4%), and TP3 (71.1%). Women with anxiety symptoms at baseline presented higher median concentrations of serum homocysteine at TP1 and lower concentrations of serum and milk B-12 at TP2 compared with women without anxiety symptoms [8 (7; 9) vs. 6 (5; 8) and 266 (188; 369) vs. 332 (272; 413)]. Milk B-12 concentrations were positively and significantly correlated with maternal serum B-12 concentrations at different TP. Women with anxiety symptoms at baseline exhibited a decrease in daily postpartum homocysteine concentrations compared to women without anxiety symptoms (β = −0.002, SE = 0.001, p = 0.024).

Conclusion

Anxiety symptoms at the end of pregnancy were associated with longitudinal changes in maternal serum homocysteine concentrations during the first 3 months postpartum.

The association between major dietary patterns and severe mental disorders symptoms among a large sample of adults living in central Iran: Baseline data of YaHS-TAMYZ cohort study

BACKGROUND

The diet's role in developing psychological disorders has been considered by researchers in recent years.

OBJECTIVE

To examine the association between major dietary patterns and severe mental disorders symptoms in a large sample of adults living in Yazd city, central Iran.

METHODS

This cross-sectional study used the baseline data of a population-based cohort study (Yazd Health study: YaHS). Dietary intakes were assessed by a multiple-choice semi-quantitative food frequency questionnaire (FFQ, Yazd nutrition survey called TAMYZ). Psychological assessments were also done by using the depression, anxiety, and stress scale-21 (DASS-21) questionnaire. Major dietary patterns were identified using principal component analysis (PCA). Analysis of covariance (ANCOVA) and logistic regression analyses were used to evaluate the relationship between dietary patterns and mental disorders symptoms.

RESULTS

A total of 7574 adults were included in the current analysis. Four major dietary patterns were identified: "Sugar and Fats", "Processed Meats and Fish", "Fruits" and "Vegetables and Red Meat". After adjustment for all confounding variables, participants in the fifth quintile of "Fruits" dietary pattern which was highly correlated with dried fruits, canned fruits, fruit juice, olive, hydrogenated fats and fruits intake, had a lower odds of severe depression (OR=0.61, 95% CI: 0.45-0.81, p for trend=0.057), anxiety (OR=0.64, 95% CI: 0.50-0.80, p for trend=0.007), and stress, (OR=0.45, 95% CI: 0.30-0.68, p for trend=0.081).

CONCLUSIONS

The intake of a dietary pattern high in dried fruits, canned fruits, fruit juice, olive, hydrogenated fats, and fruits might be inversely associated with depression, anxiety, and stress symptoms. Future prospective studies are needed to warrant this finding.

Homocysteine level at the acute stage of ischemic stroke as a biomarker of poststroke depression: A systematic review and meta-analysis

BACKGROUND

Studies on the association of homocysteine level with poststroke depression (PSD) have yielded conflicting results. This systematic review and meta-analysis aimed to evaluate the elevated homocysteine level at the acute stage of ischemic stroke in predicting PSD.

METHODS

Two authors systematically searched articles indexed in PubMed and Embase databases up to 31 January 2022. Studies evaluating the association of homocysteine level with the development of PSD in patients with acute ischemic stroke were selected.

RESULTS

A total of 10 studies involving 2,907 patients were identified. The pooled adjusted odds ratio (OR) of PSD was 3.72 [95% confidence intervals (CI) 2.03-6.81] for the top vs. bottom homocysteine level. The value of elevated homocysteine level in predicting PSD was stronger in ≥6-month follow-up (OR 4.81; 95% CI 3.12-7.43) than those in ≤ 3-month follow-up subgroup (OR 3.20; 95% CI 1.29-7.91). Moreover, a per unit increase in homocysteine level conferred a 7% higher risk of PSD.

CONCLUSION

Elevated homocysteine level in the acute stage of ischemic stroke may be an independent predictor of PSD.

Mechanisms affecting brain remodeling in depression: do all roads lead to impaired fibrinolysis?

Fibrinolysis occurs when plasminogen activators, such as tissue plasminogen activator (tPA), convert plasminogen to plasmin, which dissolves the fibrin clot. The proteolytic activity of tPA and plasmin is not restricted to fibrin degradation. In the extravascular space, these two proteases modify a variety of substrates other than fibrin, playing a crucial role in physiological and pathological tissue remodeling. In the brain, for example, tPA and plasmin mediate the conversion of brain-derived neurotrophic factor precursor (proBDNF) to mature brain-derived neurotrophic factor precursor (BDNF). Thus, the fibrinolytic system influences processes reported to be dysfunctional in depression, including neurogenesis, synaptic plasticity, and reward processing. The hypothesis that decreased fibrinolytic activity is an important element in the pathogenesis of depression is supported by the association between depression and increased levels of plasminogen activator inhibitor (PAI)-1, the main inhibitor of tPA. Also, various biochemical markers of depression induce PAI-1 synthesis, including hypercortisolism, hyperinsulinemia, hyperleptinemia, increased levels of cytokines, and hyperhomocysteinemia. Moreover, hypofibrinolysis provides a link between depression and emotional eating, binge eating, vegetarianism, and veganism. This paper discusses the role of reduced fibrinolytic activity in the bidirectional interplay between depression and its somatic manifestations and complications. It also reviews evidence that abnormal fibrinolysis links heterogeneous conditions associated with treatment-resistant depression. Understanding the role of hypofibrinolysis in depression may open new avenues for its treatment.

The role of BDNF exon I region methylation in the treatment of depression with sertraline and its clinical diagnostic value

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is considered to be one of the best candidate genes for depression. However, whether sertraline treatment affects the methylation level of this gene remains unknown.

METHODS

Fifty-three patients with depression and 51 healthy controls were included in the study. The methylation level of BDNF exon I was determined in blood samples from these subjects. The Hamilton Depression Scale was used to evaluate the depression status of patients. Single nucleotide polymorphism detection was used for genotyping, and a receiver operating characteristic (ROC) curve was used to evaluate the predictive value of the methylation level of this locus in patients with depression.

RESULTS

There was a significant difference in the methylation level of BDNF exon I between the control and depression groups. No effect of sertraline monotherapy on BDNF methylation was found in subjects with depression. Moreover, no interaction was found between BDNF genotype and the per cent methylation of BDNF exon I. However, methylation at this site was positively correlated with diurnal variation and retardation scores. Blood homocysteine concentrations were significantly reduced by sertraline treatment. No influence of genotype on serum BDNF concentration was found in subjects with depression. The ROC curve showed that methylation of BDNF exon I may be used to distinguish patients from healthy people, to a certain extent.

CONCLUSION

Methylation of BDNF exon I may be used as a biomarker of depression and may be a therapeutic target for previously untreated depression.