Decreased expression of 5-HT1A in the circumvallate taste cells in an animal model of depression

Finding the best predictive model for hypertensive depression in older adults based on machine learning and metabolomics research

Objective

Depression is a common comorbidity in hypertensive older adults, yet depression is more difficult to diagnose correctly. Our goal is to find predictive models of depression in hypertensive patients using a combination of various machine learning (ML) methods and metabolomics.

Methods

Methods We recruited 379 elderly people aged ≥65 years from the Chinese community. Plasma samples were collected and assayed by gas chromatography/liquid chromatography-mass spectrometry (GC/LC-MS). Orthogonal partial least squares discriminant analysis (OPLS-DA), volcano diagrams and thermograms were used to distinguish metabolites. The attribute discriminators CfsSubsetEval combined with search method BestFirst in WEKA software was used to find the best predicted metabolite combinations, and then 24 classification methods with 10-fold cross-validation were used for prediction.

Results

34 individuals were considered hypertensive combined with depression according to our criteria, and 34 subjects with hypertension only were matched according to age and sex. 19 metabolites by GC-MS and 65 metabolites by LC-MS contributed significantly to the differentiation between the depressed and non-depressed cohorts, with a VIP value of more than 1 and a P value of less than 0.05. There were multiple metabolic pathway alterations. The metabolite combinations screened with WEKA for optimal diagnostic value included 12 metabolites. The machine learning methods with AUC values greater than 0.9 were bayesNet and random forests, and their other evaluation measures are also better.

Conclusion

Altered metabolites and metabolic pathways are present in older adults with hypertension combined with depression. Methods using metabolomics and machine learning performed quite well in predicting depression in hypertensive older adults, contributing to further clinical research.

The bidirectional relationship of depression and disturbances in B cell homeostasis: Double trouble

Major depressive disorder (MDD) is a recurrent, persistent, and debilitating neuropsychiatric syndrome with an increasing morbidity and mortality, representing the leading cause of disability worldwide. The dysregulation of immune systems (including innate and adaptive immune systems) has been identified as one of the key contributing factors in the progression of MDD. As the main force of the humoral immunity, B cells have an essential role in the defense against infections, antitumor immunity and autoimmune diseases. Several recent studies have suggested an intriguing connection between disturbances in B cell homeostasis and the pathogenesis of MDD, however, the B-cell-dependent mechanism of MDD remains largely unexplored compared to other immune cells. In this review, we provide an overview of how B cell abnormality regulates the progression of MMD and the potential consequence of the disruption of B cell homeostasis in patients with MDD. Abnormalities of B-cell homeostasis not only promote susceptibility to MDD, but also lead to an increased risk of developing infection, malignancy and autoimmune diseases in patients with MDD. A better understanding of the contribution of B cells underlying MDD would provide opportunities for identification of more targeted treatment approaches and might provide an overall therapeutic benefit to improve the long-term outcomes of patients with MDD.

Subchronic and mild social defeat stress downregulates peripheral expression of sweet and umami taste receptors in male mice

Depression is associated with taste disorders; however, the mechanisms by which mental stress affects taste perception are not well understood. This study aimed to elucidate the effects of psychosocial stress on peripheral taste-sensing systems using a mouse depression model. Male mice were subjected to subchronic and mild social defeat stress (sCSDS). Results showed that sCSDS significantly increased body weight, food and water intake, and social avoidance behavior and that sCSDS did not change reward-seeking behavior on sucrose preference but tended to decrease pheromonal preference for female urine. Furthermore, sCSDS downregulated the mRNA levels of sweet and umami taste receptor subunits, i.e., sweet taste receptor type 1 members 2 and 3 (T1R2 and T1R3), but not the umami taste receptor subunit, i.e., taste receptor type 1 member 1 (T1R1), in the circumvallate papillae of mice. It is known that sucrose preference is mediated by the gut-brain axis without taste perception; thus, it was considered that sCSDS affected the peripheral taste-sensing systems, rather than the central reward systems, which mediate sucrose preference. This is the first study to report that psychosocial stress affects peripheral sweet and umami taste-sensing systems.

Association Between Smell, Taste, and Depression in Nationally Representative Sample of Older Adults in the United States

Objectives

To characterize the association between quantitative olfactory dysfunction (OD) and gustatory dysfunction and depression in older adults.

Methods

The 2013–2014 National Health and Nutrition Examination Survey (NHANES) data were used to investigate the relationship between smell and taste dysfunction and depression. Adults aged 65 years and older were included in the analysis. For smell status, subjects were divided into hyposmia, anosmia, and OD (hyposmia + anosmia) using the Pocket Smell Test. For taste status, subjects were evaluated using quinine, 1M NaCl, and 0.32M NaCl solutions. Indicator variables were made for subjects with both smell and taste dysfunction to determine whether a combination of symptoms could predict depression. Depression status was evaluated by the 9-item Patient Health Questionnaire using accepted cutoff values. Relevant demographic, socioeconomic, and comorbid factors were included in multivariate logistic regression models, which accounted for the complex survey design of NHANES.

Results

A total of 931 subjects aged 65 years or older were included in the weighted analysis. Anosmia significantly predicted depressive symptoms in multivariate analysis (odds ratio [OR] = 2.484, P = .032) but not univariate. In univariate analysis, hyposmia + anosmia (OR = 2.193, P = .006) and hyposmia (OR = 2.512, P < .001) significantly predicted depression. Significance was lost in multivariate analysis.

Conclusions

Smell dysfunction is an independent predictor of depressive symptoms in a representative sample of older adults in the United States after adjusting for relevant demographic factors and comorbidities.

Association between oral health-related quality of life and depressive symptoms in Chinese college students: Fitness Improvement Tactics in Youths (FITYou) project

BACKGROUND

This study aimed to investigate a gender-specific association between oral health-related quality of life (OHRQoL) and depressive symptoms in college students, as there are limited relevant studies conducted among youths.

METHODS

In 2017, a cross-sectional study of 3461 Chinese college students was conducted in Shenyang, China. OHRQoL and depressive symptoms were screened by a 14-item oral health impact profile questionnaire and a Self-rating Depression Scale, respectively. A multivariable logistic regression analysis was performed to examine the association of OHRQoL with depressive symptoms.

RESULTS

The number of youths reported to have depressive symptoms was 20.7%. A univariate analysis showed that categories with a OHRQoL score over 6 were more likely to have a higher prevalence of depressive symptoms compared to the category with a score of 0 (male: ORs [95% CI]: 3.10, 2.05-4.68, P < 0.001; female: ORs [95% CI]: 3.11, 2.38-4.05, P < 0.001). Similar results were observed after adjusting for sociodemographic, anthropometric, and lifestyle-related covariates (male: ORs [95% CI]: 3.07, 1.98-4.76, P < 0.001; female: ORs [95% CI]: 2.90, 2.21-3.81, P < 0.001).

CONCLUSIONS

College students who have higher OHRQoL tend to have a lower prevalence of depressive symptoms.

Association of alterations in smell and taste with depression in older adults

Objective

Examine the relationship between depression and changes in smell or taste.

Study Design

Cross‐sectional analysis of 2011–2012 and 2013–2014 National Health and Nutrition Examination Survey (NHANES).

Methods

We examined 5,275 adults ≥40 years old who completed smell and taste questionnaires as well as a validated depression assessment instrument, the Patient Health Questionnaire (PHQ‐9). Analyses incorporated sampling weights to account for the complex sampling design and associations were analyzed using multivariate logistic regression adjusted for related demographics and socioeconomic data.

Results

The prevalence of altered smell and taste was 23.0% (95% CI: 20.7–25.3%) and 11.9% (95% CI: 10.7–13.1%), respectively. Among those who met criteria for major depressive disorder, the prevalence of altered smell and taste was higher at 39.8% (95% CI: 33.4–46.1%) and 23.7% (95% CI: 18.7–28.7%), respectively. In a multivariate model adjusting for age, gender, education, major comorbidities, smoking history, heavy alcohol use, sinus disease, cold symptoms, and trauma history, adults ≥40 and <65 years old who reported alterations in smell (OR: 1.64, p = 0.004) and adults ≥40 years old who reported alterations in taste (OR: 1.77, p = 0.001) were more likely to meet criteria for major depressive disorder.

Conclusion

There is a strong association between major depression and alterations in smell and taste among certain age groups in the general U.S. population. Primary care providers should screen for depression when patients report changes in smell or taste.

Level of Evidence

4.

Neuronal Surface Autoantibodies in Neuropsychiatric Disorders: Are There Implications for Depression?

Autoimmune diseases are affecting around 7.6-9.4% of the general population. A number of central nervous system disorders, including encephalitis and severe psychiatric disorders, have been demonstrated to associate with specific neuronal surface autoantibodies (NSAbs). It has become clear that specific autoantibodies targeting neuronal surface antigens and ion channels could cause severe mental disturbances. A number of studies have focused or are currently investigating the presence of autoantibodies in specific mental conditions such as schizophrenia and bipolar disorders. However, less is known about other conditions such as depression. Depression is a psychiatric disorder with complex etiology and pathogenesis. The diagnosis criteria of depression are largely based on symptoms but not on the origin of the disease. The question which arises is whether in a subgroup of patients with depression, the symptoms might be caused by autoantibodies targeting membrane-associated antigens. Here, we describe how autoantibodies targeting membrane proteins and ion channels cause pathological effects. We discuss the physiology of these antigens and their role in relation to depression. Finally, we summarize a number of studies detecting NSAbs with a special focus on cohorts that include depression diagnosis and/or show depressive symptoms.