Interaction between the serotonergic system and HPA and HPT axes in patients with major depression: implications for pathogenesis of suicidal behavior

Sex differences in correlates of suicide attempts in Chinese Han first-episode and drug-naïve major depressive disorder with comorbid subclinical hypothyroidism: A cross-sectional study

BACKGROUND

This study aimed to investigate sex differences in risk factors for suicide attempts in first-episode and drug naive (FEDN) major depressive disorder (MDD) with comorbid subclinical hypothyroidism (SCH).

METHODS

A total of 1034 FEDN MDD patients with comorbid SCH were enrolled. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) positive subscale were used to assess patients' symptoms. Thyroid hormone levels and metabolic parameters were measured.

RESULTS

MDD patients with SCH had a significantly higher risk of suicide attempts than those without SCH (25.4% vs. 12.2%). Logistic regression showed that HAMA score, thyroid stimulating hormone (TSH) levels, and thyroid peroxidase antibody (TPOAb) levels were significantly associated with an increased risk for suicide attempts in both male and female MDD patients comorbid SCH, while low-density lipoprotein cholesterol (LDL-C) was significantly associated with an increased risk for suicide attempts only in male patients, HAMD score and systolic blood pressure were significantly associated with an increased risk for suicide attempts only in female patients.

CONCLUSION

SCH comorbidities may increase suicide attempts in MDD patients. Our results showed significant sex differences in clinical and metabolic factors associated with suicide attempts among FEDN MDD patients with comorbid SCH, highlighting appropriate sex-based preventive interventions are needed.

Prevalence and clinical correlates of suicide attempts in patients with first-episode drug-naïve major depressive disorder and comorbid autoimmune thyroiditis

BACKGROUND

Autoimmune thyroiditis is closely associated with major depressive disorder (MDD) and suicide attempts. However, few studies have examined this relationship.

AIMS

The study aimed to assess the prevalence and correlates of suicide attempts in patients with first-episode drug-naïve (FEDN) MDD and autoimmune thyroiditis.

METHOD

We recruited 1718 out-patients with FEDN MDD and assessed depressive, anxiety and psychotic symptoms with the Hamilton Rating Scale for Depression, Hamilton Rating Scale for Anxiety (HRSA) and Positive and Negative Syndrome Subscale positive subscale, respectively. The serum levels of free triiodothyronine, free thyroxine, thyroid stimulating hormone (TSH), antithyroglobulin, thyroid peroxidase antibody (TPOAb) and several other metabolic parameters were assessed. Patients were divided into non-autoimmune thyroiditis, autoimmune thyroiditis only and autoimmune thyroiditis with abnormal TSH groups, based on autoimmune thyroiditis severity. Multiple logistic regression model was applied to identify the correlates of suicide attempts in patients with MDD and autoimmune thyroiditis with abnormal TSH.

RESULTS

Compared with the non-autoimmune thyroiditis group, the autoimmune thyroiditis with abnormal TSH group had a nearly fourfold higher likelihood of reporting a suicide attempt, whereas no difference was found between the non-autoimmune thyroiditis and autoimmune thyroiditis only groups. HRSA score, lnTPOAb and lnTSH were independently associated with suicide attempts in patients with autoimmune thyroiditis with abnormal TSH.

CONCLUSIONS

Patients with MDD and autoimmune thyroiditis with abnormal TSH are at higher risk for suicide attempt. TPOAb, TSH and anxiety are all independently associated with suicide attempts in this population, and regular thyroid checks are warranted.

Hypothalamic-prolactin axis regulation in major depressed patients with suicidal behavior

BACKGROUND

So far, little is known about the control of hypothalamic-prolactin axis activity by dopamine (DA) and thyrotropin-releasing hormone (TRH) in depressed patients with suicidal behavior disorder (SBD).

METHODS

We evaluated prolactin (PRL) responses to apomorphine (APO; a DA direct receptor agonist) and 0800 h and 2300 h protirelin (TRH) tests in 50 medication-free euthyroid DSM-5 major depressed inpatients with SBD (either current [n = 22], or in early remission [n = 28]); and 18 healthy hospitalized controls (HCs).

RESULTS

Baseline (BL) PRL levels were comparable across the three diagnostic groups. SBDs in early remission did not differ from HCs regarding PRL suppression to APO (PRLs), PRL stimulation to 0800 h and 2300 h TRH tests (∆PRL), and ∆∆PRL values (difference between 2300 h-∆PRL and 0800 h-∆PRL values). Current SBDs showed lower PRLs and ∆∆PRL values than HCs and SBDs in early remission. Further analyses revealed that current SBDs with a history of violent and high-lethality suicide attempts were more likely to exhibit co-occurrence of low ∆∆PRL and PRL_S values.

CONCLUSIONS

Our results suggest that regulation of the hypothalamic-PRL axis is impaired in some depressed patients with current SBD, particularly those who have made serious suicide attempts. Considering the limitations of our study, our findings support the hypothesis that decreased pituitary D2 receptor functionality (possibly adaptive to increased tuberoinfundibular DAergic neuronal activity) together with decreased hypothalamic TRH drive might be a biosignature for high-lethality violent suicide attempts.

Dopamine Function and Hypothalamic-Pituitary-Thyroid Axis Activity in Major Depressed Patients with Suicidal Behavior

Involvement of the dopaminergic (DA) and hypothalamic-pituitary-thyroid (HPT) systems in suicidal behavior is still poorly understood. We assessed multihormonal responses to apomorphine (APO; a short acting DA receptor agonist) and 8 AM and 11 PM protirelin (TRH) tests in 30 medication-free DSM-5 euthyroid major depressed inpatients with suicidal behavior disorder (SBD) (current, n = 14; in early remission, n = 16) and 18 healthy hospitalized control subjects (HCs). Compared to HCs, responses to APO and TRH tests were unaltered in SBDs in early remission. However, current SBDs exhibited increased APO-induced growth hormone (GH) and adrenocorticotropin (ACTH) stimulation, and reduced 11 PM thyrotropin (TSH) and ∆∆TSH values (difference between 11 PM and 8 AM TRH-TSH responses). In current SBDs, the association between high APO-GH concentrations and low ∆∆TSH values was more common in recent suicide attempters than in past suicide attempters. These preliminary results suggest that co-occurring alterations in the DA and HPT systems (i.e., DA receptor hyperresponsiveness associated with decreased hypothalamic TRH drive) may contribute to the pathophysiology of suicidal behavior. Conversely, normalization of DA and TRH functions might reflect a process of recovery from suicidality. Thus, our findings suggest that drugs targeting the DAergic and TRH systems could be relevant in suicide prevention.

Association and Genetic Expression between Genes Involved in HPA Axis and Suicide Behavior: A Systematic Review

BACKGROUND

Suicide behavior (SB) has been highly associated with the response to stress and the hypothalamic-pituitary-adrenal (HPA) axis. The aim of this study was to summarize the results obtained in genetic studies that analyzed the HPA axis-stress pathway and SB through a systematic review.

METHODS

We performed an online search in PubMed, EBSCO, Web of Science, Scopus, and PsycoInfo databases up to May 2021. We followed the PRISMA guidelines for systematic reviews. We included case-control and expression studies that provided data on mRNA expression and single-nucleotide polymorphisms of genes associated with SB.

RESULTS

A total of 21,926 individuals participated across 41 studies (not repeats); 34 studies provided data on single-nucleotide polymorphisms in 21,284 participants and 11 studies reported data on mRNA expression in 1034 participants. Ten genes were identified: FKBP5, CRH, CRHBP, CRHR1, CRHR2, NR3C1, NR3C2, SKA2, MC2R, and POMC.

CONCLUSIONS

Our findings suggest that key stress pathway genes are significantly associated with SB and show potential as biomarkers for SB.

Thyroid axis activity and dopamine function in depression

BACKGROUND

Several lines of evidence suggest alterations in both hypothalamic-pituitary-thyroid (HPT) axis and dopamine (DA) function in depressed patients. However, the functional relationships between HPT and DA systems have not been well defined.

METHODS

We examined thyrotropin (TSH) response to 0800 h and 2300 h protirelin (TRH) challenges, and adrenocorticotropic hormone (ACTH), cortisol and growth hormone (GH) responses to apomorphine (APO, a DA receptor agonist), in 58 drug-free DSM-IV major depressed inpatients without a suicidal behavior, and 22 healthy hospitalized controls.

RESULTS

Compared with controls, patients showed 1) lower basal serum 2300 h-TSH, 2300 h-∆TSH, and ∆∆TSH (difference between 2300 h-∆TSH and 0800 h-∆TSH) levels, and 2) lower cortisol response to APO (∆COR). A negative relationship between ∆∆TSH values and hormonal responses to APO was observed in the depressed group, but not in the control group. When patients were classified on the basis of their ∆∆TSH status, patients with reduced ∆∆TSH values (< 2.5 mU/L) showed hormonal APO responses comparable to those of controls. Patients with normal ∆∆TSH values exhibited lower ∆ACTH, ∆COR, and ∆GH values than patients with reduced ∆∆TSH values and controls.

CONCLUSION

Taken together, these results suggest that hypothalamic DA function is unaltered in depressed patients with HPT dysregulation (i.e., increased hypothalamic TRH drive leading to altered TRH receptor chronesthesy on pituitary thyrotrophs). Conversely, hypothalamic DA-receptor function is decreased in patients with normal HPT axis activity. These findings are discussed in the context of the role of TRH as a homeostatic neuromodulator in depression.

Neuroendocrine Assessment of Dopaminergic Function during Antidepressant Treatment in Major Depressed Patients

The effects of antidepressants on dopamine (DA) receptor sensitivity in the mesolimbic–hypothalamic system have yielded contradictory results. The postsynaptic DA receptor function was evaluated by the cortisol response to apomorphine (APO; 0.75 mg SC) in 16 drug-free DSM-5 major depressed inpatients and 18 healthy hospitalized control (HC) subjects. Cortisol response to the dexamethasone suppression test (DST) was also measured. After two and four weeks of antidepressant treatment (ADT), the DST and APO test were repeated in all patients. Cortisol response to APO (∆COR) was not influenced by the hypothalamic–pituitary–adrenal (HPA) axis activity, as assessed by the DST. Pre-treatment ∆COR values did not differ significantly between patients and HCs. During ADT, ∆COR values were lower than in HCs at week 2 and 4. After four weeks of treatment, among the eight patients who had blunted ∆COR values, seven were subsequent remitters, while among the eight patients who had normal ∆COR values, seven were non-remitters. Considering the limitations of our study, the results suggest that following chronic ADT, the desensitization of postsynaptic DA receptors connected with the regulation of the HPA axis at the hypothalamic level is associated with clinical remission. These results could reflect increased DA levels in the mesolimbic pathway.

The Role of GnIH in Biological Rhythms and Social Behaviors

Gonadotropin-inhibitory hormone (GnIH) was first discovered in the Japanese quail, and peptides with a C-terminal LPXRFamide sequence, the signature protein structure defining GnIH orthologs, are well conserved across vertebrate species, including fish, reptiles, amphibians, avians, and mammals. In the mammalian brain, three RFamide-related proteins (RFRP-1, RFRP-2, RFRP-3 = GnIH) have been identified as orthologs to the avian GnIH. GnIH is found primarily in the hypothalamus of all vertebrate species, while its receptors are distributed throughout the brain including the hypothalamus and the pituitary. The primary role of GnIH as an inhibitor of gonadotropin-releasing hormone (GnRH) and pituitary gonadotropin release is well conserved in mammalian and non-mammalian species. Circadian rhythmicity of GnIH, regulated by light and seasons, can influence reproductive activity, mating behavior, aggressive behavior, and feeding behavior. There is a potential link between circadian rhythms of GnIH, anxiety-like behavior, sleep, stress, and infertility. Therefore, in this review, we highlight the functions of GnIH in biological rhythms, social behaviors, and reproductive and non-reproductive activities across a variety of mammalian and non-mammalian vertebrate species.

Deiodinases, organic anion transporter polypeptide polymorphisms and symptoms of anxiety and depression after ischemic stroke

BACKGROUND

Emotional disturbances, such as anxiety and depression are common after acute ischemic stroke (AIS). Individual variation in emotional outcome is strongly influenced by genetic factors. One of pituitary axis, is the hypothalamic-pituitary-thyroid axis, a critical regulator of post-stroke recovery, suggesting that allelic variants in thyroid hormone (TH) signaling regulation can influence stroke outcome.

AIM

To determine associations between AIS emotional outcome and allelic variants of the TH metabolizing enzymes 1-3 type deiodinase (DIO1-3) and the membrane transporting organic anion polypeptide 1C1 (OATP1C1).

METHODS

Eligible AIS patients from Lithuania (n=168) were genotyped for ten DIO1-3 and OATP1C1 single nucleotide polymorphisms (SNP): DIO1 rs12095080-A/G, rs11206244-C/T, and rs2235544-A/C; DIO2 rs225014-T/C and rs225015-G/A; DIO3 rs945006-T/G; OATP1C1 rs974453-G/A, rs10444412-T/C, rs10770704-C/T, and rs1515777-A/G. Emotional outcome was evaluated using the Hospital Anxiety and Depression Scale at discharge from the neurology department after experienced index AIS.

RESULTS

After adjustment for potential confounders, the major allelic (wild-type) DIO1-rs12095080 genotype (AA) was associated with higher odds ratio of anxiety symptoms (OR = 5.16; 95% CI: 1.04-25.58; p = 0.045), conversely, DIO1-rs11206244 wild-type genotype (CC) and wild-type OATP1C1-rs1515777 allele containing the genotypes (AA + AG) were associated with lower odds ratio of symptoms of anxiety (OR = 0.37; 95% CI: 0.14-0.96; p = 0.041 and OR = 0.30; 95% CI: 0.12-0.76; p = 0.011, respectively). Wild-type OATP1C1-rs974453 genotype (GG) was associated with higher odds ratio of symptoms of depression (OR = 2.73; 95% CI: 1.04-7.12; p = 0.041).

CONCLUSION

Allelic variants in thyroid axis genes may predict emotional outcomes of AIS.

The negative effects of social bond disruption are partially ameliorated by sertraline administration in prairie voles

Negative social experiences influence both depression and cardiovascular dysfunction. Many individuals who experience negative mood states or cardiovascular conditions have limited social support. Therefore, investigation of drug treatments that may protect against the consequences of social stress will aid in designing effective treatment strategies. The current study used an animal model to evaluate the protective effect of sertraline administration on behavioral and cardiovascular consequences of social stress. Specifically, male prairie voles (Microtus ochrogaster), which are socially monogamous rodents that share several behavioral and physiological characteristics with humans, were isolated from a socially-bonded female partner, and treated with sertraline (16 mg/kg/day, ip) or vehicle during isolation. Unexpectedly, sertraline did not protect against depression-relevant behaviors, and it was associated with increased short- and long-term heart rate responses. However, sertraline administration improved heart rate variability recovery following a behavioral stressor, including increased parasympathetic regulation, and altered long-term neuronal activity in brain regions that modulate autonomic control and stress reactivity. These results indicate that sertraline may partially protect against the consequences of social stressors, and suggest a mechanism through which sertraline may beneficially influence neurobiological control of cardiac function.

The prevalence of impaired glucose regulation in anxiety disorder patients and the relationship with hypothalamic-pituitary-adrenal axis and hypothalamic-pituitary-thyroid axis activity

OBJECTIVE

To investigate the prevalence of impaired glucose regulation (IGR) in patients with anxiety disorders and the relationship with hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-thyroid (HPT) axes function.

METHODS

From September 2013 to May 2015, a total of 646 patients with anxiety disorders who matched the criteria of the 10th revision of the International Statistical Classification of Diseases and Related Health Problems participated in our study, which was conducted in the Psychiatric Inpatient Department of the West China Hospital of Sichuan University. The results from 75-g glucose tolerance tests, and morning (8:00 am) serum cortisol (PTC), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), TT3, TT4, FT3, and FT4 levels were collected. The Hamilton Anxiety Scale was administered to assess the severity of anxiety. SPSS 17.0 software was used for statistical analysis.

RESULTS

The crude prevalence of impaired glucose regulation was 24.61% in patients with anxiety disorders patients. In the 18- to 40-year age group with impaired glucose regulation (IGR), both ACTH and PTC levels were higher than the control group (P < 0.05). In the 61- to 75-year age group with IGR, the TSH level was lower and the FT4 level was higher than the control group (P < 0.05).

CONCLUSION

The results herein partially confirm that the prevalence of IGR in patients with anxiety disorders is high. Impaired glucose in the younger age group is closely associated with HPA axis function, while impaired glucose in the older age group is closely associated with HPT axis alteration. Therefore, routine blood glucose and endocrine function testing in patients with anxiety disorder is of clinical importance to prevent the development of diabetes.

Regulation of Fibroblast Growth Factor 23 by Iron, EPO, and HIF

Purpose of review

Fibroblast growth factor-23 (FGF23) is the key hormone produced in bone critical for phosphate homeostasis. Elevated serum phosphorus and 1,25dihydroxyvitaminD stimulates FGF23 production to promote renal phosphate excretion and decrease 1,25dihydroxyvitaminD synthesis. Thus completing the feedback loop and suppressing FGF23. Unexpectedly, studies of common and rare heritable disorders of phosphate handling identified links between iron and FGF23 demonstrating novel regulation outside the phosphate pathway.

Recent Findings

Iron deficiency combined with an FGF23 cleavage mutation was found to induce the autosomal dominant hypophosphatemic rickets phenotype. Physiological responses to iron deficiency, such as erythropoietin production as well as hypoxia inducible factor activation, have been indicated in regulating FGF23. Additionally, specific iron formulations, used to treat iron deficiency, alter post-translational processing thereby shifting FGF23 protein secretion.

Summary

Molecular and clinical studies revealed that iron deficiency, through several mechanisms, alters FGF23 at the transcriptional and post-translational level. This review will focus upon the novel discoveries elucidated between iron, its regulators, and their influence on FGF23 bioactivity.

Prolactin and thyroid hormone levels are associated with suicide attempts in psychiatric patients

The aim of this study is to evaluate biological factors associated with recent suicidal attempts in a naturalistic sample. A total of 439 patients suffering from major depression disorder (MDD), bipolar disorder (BD) and psychotic disorders (schizophrenia, schizoaffective disorder and psychosis not otherwise specified), who were consecutively assessed in the Emergency Department of an Italian Hospital (January 2008-December 2009), were included. In the whole sample, suicide attempters and non-attempters differed with regard to free triiodothyronine (FT3) and prolactin values only. A univariate general linear model indicated significant effects of sex (F(1;379)=9.29; P=0.002), suicidal status (F(1;379)=4.49; P=0.04) and the interaction between sex and suicidal status (F(1;379)=5.17; P=0.02) on prolactin levels. A multinomial logistic regression model indicated that suicidal attempters were 2.27 times (odds ratio (OR)=0.44; 95% confidence interval (95%CI): 0.23/0.82; P=0.01) less likely to have higher FT3 values than non-attempters; while prolactin values failed to reach statistical significance (OR=0.99; 95%CI: 0.98/1.00; P=0.051). Both prolactin and thyroid hormones may be involved in a complex compensatory mechanism to correct reduced central serotonin activity. Further studies may help in understanding how these findings can be used by clinicians in assessing suicide risk.

Thyroid axis activity and suicidal behavior in depressed patients

The aim of this study was to investigate the relationship between suicidal behavior and hypothalamic-pituitary thyroid (HPT) axis activity in depressed patients. The serum levels of thyrotropin (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were evaluated before and after 0800 and 2300 h thyrotropin-releasing hormone (TRH) challenges, on the same day, in 95 medication-free DSM-IV euthyroid major depressed inpatients and 44 healthy hospitalized controls. Compared to controls: (1) patients with a positive suicide history (PSH; n=53) showed lower basal FT4 (at 0800 h: p<0.005; at 2300 h: p<0.03), but normal FT3 levels, while patients with a negative suicide history (NSH; n=42) showed normal FT4 and FT3 levels; (2) TSH responses to TRH (DeltaTSH) were blunted in NSHs (at 0800 h: p<0.03; at 2300 h: p<0.00001), but not in PSHs; (3) both NSHs and PSHs showed lower DeltaDeltaTSH values (differences between 2300 h-DeltaTSH and 0800 h-DeltaTSH) (p<0.000001 and p<0.003, respectively). Compared to NSHs, basal FT4 levels were reduced in PSHs (at 0800 h: p<0.002; at 2300h: p<0.006). HPT parameters were not significantly different between recent suicide attempters (n=32) and past suicide attempters (n=21). However, compared to controls, recent suicide attempters showed lower 2300 h-DeltaTSH (p<0.04) and DeltaDeltaTSH (p<0.002) values, and lower basal FT4 values (at 0800 h: p<0.006; at 2300 h: p<0.02). Our results, obtained in a large sample of depressed inpatients, indicate that various degrees of HPT axis dysregulation are associated with the history of suicide.