Dopamine-prolactin pathway potentially contributes to the schizophrenia and type 2 diabetes comorbidity

Striatal dopamine gene network moderates the effect of early adversity on the risk for adult psychiatric and cardiometabolic comorbidity

Cardiometabolic and psychiatric disorders often co-exist and share common early life risk factors, such as low birth weight. However, the biological pathways linking early adversity to adult cardiometabolic/psychiatric comorbidity remain unknown. Dopamine (DA) neurotransmission in the striatum is sensitive to early adversity and influences the development of both cardiometabolic and psychiatric diseases. Here we show that a co-expression based polygenic score (ePGS) reflecting individual variations in the expression of the striatal dopamine transporter gene (SLC6A3) network significantly interacts with birth weight to predict psychiatric and cardiometabolic comorbidities in both adults (UK Biobank, N = 225,972) and adolescents (ALSPAC, N = 1188). Decreased birth weight is associated with an increased risk for psychiatric and cardiometabolic comorbidities, but the effect is dependent on a striatal SLC6A3 ePGS, that reflects individual variation in gene expression of genes coexpressed with the SLC6A3 gene in the striatum. Neuroanatomical analyses revealed that SNPs from the striatum SLC6A3 ePGS were significantly associated with prefrontal cortex gray matter density, suggesting a neuroanatomical basis for the link between early adversity and psychiatric and cardiometabolic comorbidity. Our study reveals that psychiatric and cardiometabolic diseases share common developmental pathways and underlying neurobiological mechanisms that includes dopamine signaling in the striatum.

Sini San ameliorates lipid metabolism in hyperprolactinemia rat with liver-depression

Sini San (SNS) is used to treat liver depression and is applied in both food and herbal medicine. Hyperprolactinemia (HPRL) is a common endocrine disorder, and patients with HPRL are usually associated with depressive symptoms. However, whether SNS is effective in treating HPRL combined with liver depression and its underlying mechanisms are unknown. We applied network pharmacology and molecular docking to predict the mechanism of SNS for the treatment of liver-depressed HPRL. Therapeutic effects were validated in animal models and cells. Metabolomics was also used to evaluate the effect of SNS on liver-depressed HPRL. Network pharmacology and molecular docking analysis showed that AKT1, TNF and IL6 were the key targets, and SNS improved depressive behaviors, regulated sex hormone levels, and improved ovarian morphology. Combined network pharmacology and metabolomics analyses showed that SNS could act by regulating lipid metabolism. In addition, SNS significantly reduced the release of prolactin (PRL) in rat pituitary tumor MMQ cells. Overall, SNS can significantly treat HPRL liver depression at both animal and cellular levels, and effectively alleviate the related symptoms by regulating lipid metabolism. AKT1, TNF and IL6 may be key targets.

COMT Variants are Associated With Breast and Nipple Pain

Estimates suggest that only 24.9% of infants born in 2019 were exclusively breastfed before 6 months of age, despite the known health benefits of exclusive breastfeeding. Breast and nipple pain is one of the primary determinants of exclusive breastfeeding. Environmental contributions to breastfeeding success have been reported extensively in the literature, but the contribution(s) of maternal genetics has yet to be discovered. The purpose of the study was to identify an association between pain and lactation-related gene variants with exclusive breastfeeding determinants. We selected 4 genes having single nucleotide polymorphisms (SNPs) with potential functional significance in breastfeeding and pain: prolactin receptor (PRLR), oxytocin receptor (OXTR), catechol-O-methyltransferase (COMT), and milk fat globule epidermal growth factor and factor V/VIII domain containing (MFGE8). We performed a cross-sectional secondary analysis of a longitudinal randomized controlled trial study, Promoting Self-Management of Breast and Nipple Pain with Biomarkers and Technology for Breastfeeding Women (NCT05262920). Breast and nipple pain, perceived insufficient milk, and breastfeeding self-efficacy were examined using total scale scores for the Brief Pain Inventory, Visual Analog Scale, H&H Lactation Scale, and the Breastfeeding Self-efficacy Scale-short form, respectively. Of the candidate genes examined, SNPs within COMT were significantly associated with breastfeeding-related outcomes. Specifically, COMT rs4633 and rs4680 minor allele carriers (T, A) reported higher breast and nipple pain intensity than women homozygous for the major allele (C, G). COMT is the most widely researched "pain gene" and has been linked to cold, postoperative, and postpartum pain. This study is the first to identify a contribution of COMT variants to breast and nipple pain and, as a result, to breastfeeding exclusivity. PERSPECTIVE: Two SNPs in the pain gene COMT are associated with breast and nipple pain. Clinically, a minor allele in COMT rs4633 and rs4680 may increase a woman's rating of moderate breast and nipple pain. TRIAL REGISTRATION: PROMPT was registered in ClinicalTrials.gov (protocol #NCT05262920).

A systems biology approach for discovering the cellular and molecular aspects of psychogenic non-epileptic seizure

Objectives

Psychogenic non-epileptic seizure (PNES) is the most common non-epileptic disorder in patients referring to epilepsy centers. Contrary to common beliefs about the disease's harmlessness, the death rate of PNES patients is similar to drug-resistant epilepsy. Meanwhile, the molecular pathomechanism of PNES is unknown with very limited related research. Thus, the aim of this in silico study was to find different proteins and hormones associated with PNES via a systems biology approach.

Methods

Different bioinformatics databases and literature review were used to find proteins associated with PNES. The protein-hormone interaction network of PNES was constructed to discover its most influential compartments. The pathways associated with PNES pathomechanism were found by enrichment analysis of the identified proteins. Besides, the relationship between PNES-related molecules and psychiatric diseases was discovered, and the brain regions that could express altered levels of blood proteins were discovered.

Results

Eight genes and three hormones were found associated with PNES through the review process. Proopiomelanocortin (POMC), neuropeptide Y (NPY), cortisol, norepinephrine, and brain-derived neurotrophic factor (BDNF) were identified to have a high impact on the disease pathogenesis network. Moreover, activation of Janus kinase-signaling transducer and activator of transcription (JAK-STAT) and JAK, as well as signaling of growth hormone receptor, phosphatidylinositol 3-kinase /protein kinase B (PI3K/AKT), and neurotrophin were found associated with PNES molecular mechanism. Several psychiatric diseases such as depression, schizophrenia, and alcohol-related disorders were shown to be associated with PNES predominantly through signaling molecules.

Significance

This study was the first to gather the biochemicals associated with PNES. Multiple components and pathways and several psychiatric diseases associated with PNES, and some brain regions that could be altered during PNES were suggested, which should be confirmed in further studies. Altogether, these findings could be used in future molecular research on PNES patients.

Recent findings on subjective well-being and physical, psychiatric, and social comorbidities in individuals with schizophrenia: A literature review

AIM

Care for people with schizophrenia is shifting the locus from long-stay mental hospitals to nonspecialized community-based settings. Knowledge on the care is not a sole property of psychiatric specialists. Community healthcare workers who do not specialize in psychiatry are recommended to learn more about schizophrenia. This review aimed to summarize recent findings on subjective well-being and physical, psychiatric, and social comorbidities in individuals with schizophrenia.

METHODS

A literature review was conducted. We retrieved findings from existing systematic reviews and meta-analyses as our preferred method. When data were not available, we referred to other types of studies.

RESULTS

As per our review, individuals with schizophrenia demonstrated poor subjective well-being, happiness, and life satisfaction despite individual differences. Pharmacotherapy caused weight gain and constipation, whereas race and hospitalization might affect weight reduction. Individuals with schizophrenia demonstrated poor oral health, a high prevalence of noncommunicable diseases, and unique eating behaviors. Depression, sleep disorders, smoking, and alcohol and drug consumption were frequently found in the individuals. Research findings regarding problematic internet and smartphone use and stress perception were limited. Low health literacy and neglect of preventable behaviors were frequently seen in individuals with schizophrenia. They tended to be less educated, poor, unemployed, unmarried/unattached, and had poor social cognition, resulting in little social support and a small social network.

CONCLUSION

Retrieving recent data, we confirmed that individuals with schizophrenia had poor subjective well-being and suffer from various physical, psychiatric, and social comorbidities.

Crosstalk between Schizophrenia and Metabolic Syndrome: The Role of Oxytocinergic Dysfunction

The high prevalence of metabolic syndrome in persons with schizophrenia has spurred investigational efforts to study the mechanism beneath its pathophysiology. Early psychosis dysfunction is present across multiple organ systems. On this account, schizophrenia may be a multisystem disorder in which one organ system is predominantly affected and where other organ systems are also concurrently involved. Growing evidence of the overlapping neurobiological profiles of metabolic risk factors and psychiatric symptoms, such as an association with cognitive dysfunction, altered autonomic nervous system regulation, desynchrony in the resting-state default mode network, and shared genetic liability, suggest that metabolic syndrome and schizophrenia are connected via common pathways that are central to schizophrenia pathogenesis, which may be underpinned by oxytocin system dysfunction. Oxytocin, a hormone that involves in the mechanisms of food intake and metabolic homeostasis, may partly explain this piece of the puzzle in the mechanism underlying this association. Given its prosocial and anorexigenic properties, oxytocin has been administered intranasally to investigate its therapeutic potential in schizophrenia and obesity. Although the pathophysiology and mechanisms of oxytocinergic dysfunction in metabolic syndrome and schizophrenia are both complex and it is still too early to draw a conclusion upon, oxytocinergic dysfunction may yield a new mechanistic insight into schizophrenia pathogenesis and treatment.

Distinctive features of the hypothalamic-pituitary-gonadal axis and the level of dopamine in men of the European and Asian North

In recent years, there has been a decrease in reproductive potential, especially among residents of the Arctic territories, having the greatest stress from various body systems, including the state of the hormonal regulation of the male reproductive system. The study of the dopamine levels and the content of sex hormones in the male population of various Arctic regions is relevant due to the increased stress on the part of the dopaminergic system and the hypothalamic-pituitary-gonadal axis in residents of the Northern regions, as well as the lack of information about their interaction among the apparently healthy population. The aim of the investigation is to study the possible effect of various plasma concentrations of the dopamine on the content of sex hormones and sex-steroid-binding β-globulin (SHBG) in apparently healthy men in the Arctic zone of the Russian Federation, taking into account the territory of residence. There were examined 181 men aged 22-60 years, living in the territories of the European and Asian North. The levels of sex hormones, SHBG, and dopamine were determined by the enzyme-linked immunosorbent assay. The inhabitants of the Asian North in comparison with the men of the European North have higher levels of dopamine, luteinizing hormone, progesterone, prolactin, estradiol and SHBG with decreased serum levels of free fractions of testosterone. Reference levels of dopamine in men from the European North are combined with the stimulatory effect of dopamine on LH levels, which may indicate an increase steroidogenesis. The high levels of dopamine in men from the Asian North are combined with increased level of estradiol, which may be related to the effect of dopamine on testosterone aromatization. The separate region with its ecological differences is characterized by the presence of features of compensatory-adaptive reactions of an organism in male representatives on the part of the dopaminergic system and the hypothalamic-pituitary-gonadal axis. The identified features can help in carrying out preventive measures aimed at preserving the male reproductive potential of the inhabitants of the Arctic territories.

Pharmacological strategies for sexual recovery in men undergoing antipsychotic treatment

INTRODUCTION

: First- and second-generation antipsychotics are highly accountable for causing a plethora of medical side effects, ranging from metabolic imbalances to sexual dysfunction (SD), that frequently undermine patient-doctor relationships. Nevertheless, to date antipsychotics are one of the best treatment options for dealing with numerous either acute or chronic conditions like agitation, suicidality, depression, dementia, and of course psychosis. For these reasons, clinicians need to handle them wisely to preserve patients' sexual health, avoid poor therapeutic adherence and prevent high rates of therapy drop-out.

AREAS COVERED

: This article reviews the literature on pharmacologic approaches for management strategies in men who are administered with antipsychotics and developed SD. The etiology of antipsychotic-induced SD is also discussed.

EXPERT OPINION

: Clinicians must consider sexual life as a major health domain. To do so, a first step would be to measure and monitor sexual function by means of psychometric tools. Secondly, primary prevention should be conducted when choosing antipsychotics, i.e., picking sex-sparing compounds like aripiprazole or brexpiprazole. Thirdly, if sexolytic compounds cannot be dismissed, such as first-generation antipsychotics, risperidone, paliperidone, or amisulpride, then aripiprazole 5-20 mg/day adjunctive therapy has proven to be most effective in normalizing prolactin levels and consequently treating antipsychotic-induced SD.

Decipher the inhibitory potential of phytocompounds from Leptadenia reticulata on dopamine D2 receptor to enhance prolactin secretion

Dopamine is secreted by the hypothalamus, which inhibits the proliferation and effectiveness of lactotroph cells that release prolactin via dopamine D2 receptor (D2R). D2R activation inhibits lactotroph cell prolactin synthesis and regulates prolactin gene expression. Although, commercial medications are available for hypogalactia and agalactia, various plant sources significantly alleviate these problems. Leptadenia reticulata (Jivanti) is one of the important medicinal plants often consumed by nursing mothers to improve breast milk production. However, mechanism and chemical constituents involved in the inhibition of D2R by Jivanti is unclear. Therefore, in this study the phytocompounds reported from Jivanti were used for in-silico analysis to predict D2R inhibitory potential. The binding affinity value of campesterol and β-sitosterol (- 10.1 and -10.0 kcal/mol) with D2R has high revealed by molecular docking and stable interaction reveled by molecular dynamics simulation. Thus, these lead compounds could exert more D2R inhibitory activity resulting into prolactin release, which may lead to an increase in breast milk production. Although all selected compounds had fine permeation, non-toxic, and non-carcinogenic characteristics predicted by ADMET, campesterol had good solubility, absorption characteristics compared to other. Therefore, Jivanti, which is traditionally known medicinal plant, could be explored as a medication candidate to boost breast milk production.

Levels of Trace Elements in Erythrocytes as Endocrine Disruptors in Obese and Nonobese Women with Polycystic Ovary Syndrome

Introduction: Polycystic ovary syndrome (PCOS) is one of the most commonly recognized endocrinopathies in women. The literature lacks clear data that allow any meaningful conclusions to be drawn about the influence of trace elements in erythrocytes on the biochemical parameters of PCOS. Materials and methods: This study was conducted among 47 women meeting the Rotterdam criteria for the diagnosis of polycystic ovary syndrome. The research groups included women with PCOS with different BMI values (body mass index): obese women with PCOS (PCOS with BMI ≥ 30, mean BMI index 35.4 ± 4.4 kg/m²), nonobese PCOS women (PCOS with BMI < 30, mean BMI index 25.2 ± 2.8 kg/m²), and healthy control group (CG) with a mean BMI of 23.57 ± 0.9 kg/m². The contents of trace elements in erythrocytes were determined with an inductively coupled plasma atomic emission spectrometer. Results: The only trace element showing significant differences in concentration between the studied groups was nickel (Ni). The level of nickel in the obese women with PCOS (BMI ≥ 30) was significantly higher than in nonobese women (BMI < 30). The content of other trace elements in erythrocytes did not differ significantly between the studied groups. Several significant correlations were found within each of the studied PCOS groups: in the group of obese women, the content of zinc (Zn) in erythrocytes positively correlated with prolactin, the content of magnesium (Mg) positively correlated with testosterone, and the content of manganese (Mn) negatively correlated with thyroid-stimulating hormone. In the group of nonobese women, Zn content correlated positively with testosterone, Ni with luteinizing hormone (LH) and estradiol, and Mg negatively correlated with estradiol. Conclusions: The relationship between the level of trace elements and the level of hormones suggests that, in obese women with PCOS, nickel may play a role in inhibiting the processes of folliculogenesis and ovulation. Research on trace elements and their relationship to ovulatory cycles and the development of PCOS may contribute to reducing the consequences of PCOS and, therefore, should be extended.

Associations among the TREM-1 Pathway, Tau Hyperphosphorylation, Prolactin Expression, and Metformin in Diabetes Mice

INTRODUCTION

Diabetes mellitus (DM) is a risk factor for Alzheimer's disease (AD). Increasing evidence indicates that the triggering receptor expressed on myeloid cells (TREM)-1 amplifies chronic inflammation, as well as the roles of prolactin (PRL) and metformin (MET) in tau hyperphosphorylation. However, the associations among TREM-1, tau hyperphosphorylation, PRL expression, and MET in DM remain unclear.

METHODS

Streptozotocin was used to induce experimental DM in C57BL/6N mice. MET was orally administered at a dose of 400 mg/kg body weight for 6 weeks prior to hippocampal collection in DM mice. Various parameters pertaining to the TREM-1 pathway, tau hyperphosphorylation, PRL, and related factors were analyzed.

RESULTS

Quantitative polymerase chain reaction and Western blot analysis demonstrated that the expression levels of TREM-1, DAP12, casp1, interleukin-1β, Cox2, inducible nitric oxide synthase, pituitary transcriptional factor-1 (Pit-1), and PRL were significantly increased in the hippocampus of DM mice; the expression levels of these pro-inflammatory mediators, PRL receptor (PRLR) short or long (PRLR-S and PRLR-L), and PRL regulatory element-binding (Preb) protein in DM mice treated with MET (DM + MET) were significantly decreased compared with those in control (CON) mice. The levels of p-Tau and glycogen synthase kinase-3 in the DM group were significantly higher than those in the CON group and significantly lower than those in the DM + MET group.

CONCLUSION

We confirmed the therapeutic potential of MET for both DM and neurodegeneration. Our findings shed new light on the effects of DM on the pathophysiology of AD via the TREM-1 pathway and PRL expression. Thus, an improved understanding of the TREM-1 pathway in hyperglycemic conditions, as well as PRL, Preb, Pit-1, PRLR-L, and PRLR-S gene expression in the liver, brain, and other sites, may help unravel the pathogenesis of insulin resistance and neurodegeneration.

Estrogen receptor: A potential linker of estrogenic and dopaminergic pathways in zebrafish larvae following deltamethrin exposure

Deltamethrin (DM), a type II pyrethroid insecticide, is widely used to control agricultural pests. However, its excessive use exerts a detrimental effect on the ecological environment and human health, indicating the need to study its potential risks in detail. In the present study, zebrafish embryos were exposed to varying concentrations of DM (0.1, 1, 10, and 25 μg/L) for 96 h to assess the alterations in the transcript levels of proteins of the estrogenic and dopaminergic pathways. In addition, its effect on zebrafish locomotor activity was studied. The mRNA expression of cyp19a1b, erα, erβ2, fshr, gnrh2, gnrhr3, vtg3, dat, and dr1 significantly changed after exposing the embryos to DM. Deltamethrin at 10 and 25 μg/L significantly reduced the average swimming speed of zebrafish larvae. In addition, embryos injected with zebrafish estrogen receptor α (erα) and β (erβ) morpholinos and co-exposed to 25 μg/L DM for 96 h showed reduced expression of vtg3 mRNA compared to embryos exposed to 25 μg/L DM only. The locomotor activity of erα and erβ knockdown zebrafish following DM exposure was increased significantly when compared with that of larvae exposed to 25 μg/L DM only. Our results demonstrated that DM altered the locomotor activity of zebrafish larvae and the transcript levels of the components of estrogenic and dopaminergic pathways; erα and erβ knockdown weakened these effects.

Prolactin, metabolic and immune parameters in naïve subjects with a first episode of psychosis

BACKGROUND

Prolactin (Prl) is a pleiotropic hormone initially described for its regulation of lactation in mammals but later associated with metabolic and immune homeostasis, stress, inflammatory response and human behavior. Its regulation through dopamine receptors highlights its importance in psychiatry mostly because hyperprolactinemia is a common secondary side effect of dopamine antagonists. Despite its undeciphered patho-physiological mechanisms, hyperprolactinemia in naïve psychosis patients has been widely described. Its consequences might underlie the increased morbidity and early mortality found in naïve subjects as described in the general population where prolactin values have been correlated with inflammatory, immune and metabolic parameters.

METHODS

We aimed to evaluate the correlation between prolactin values and other biochemical parameters (C-reactive Protein-CrP, blood cell count, lipid and hepatic profile, fasting glucose) in a cohort of first episode psychosis naïve subjects (N = 491) stratified by sex. Regression analyses with confounders were performed to evaluate the association.

FINDINGS

Prl displayed significant correlations with C-Reactive Protein (CrP), Low-Density Lipoprotein (LDL), Aspartate Transaminase (AST) for females and High-Density Lipoprotein (HDL) and eosinophil count for males. However, and despite previous specific sex correlations, significant associations were described for CrP, HDL, LDL, AST and ALT without sex interaction and despite confounders such as age, Body Mass Index or smoking status.

CONCLUSIONS

Our results show a specific relation of Prl with immune and metabolic parameters describing a heterogeneous pattern. Our results suggest that prolactin might underlie the excess of morbidity and early mortality in naïve patients through a specific pathway.

The Relationships Between Hyperprolactinemia, Metabolic Disturbance, and Sexual Dysfunction in Patients With Schizophrenia Under Olanzapine Treatment

The aim of the study was to assess the relationship between prolactin levels and sexual dysfunction in patients with schizophrenia who use olanzapine medication. The potential risk factors of hyperprolactinemia and sexual dysfunction were also investigated. Patients with schizophrenia undergoing olanzapine monotherapy were invited to participate in this cross-sectional study. The Arizona Sexual Experiences Scale (ASEX) and the Positive and Negative Syndrome Scale were used to evaluate subjective sexual dysfunction and psychopathology, respectively. Levels of prolactin and metabolic parameters were also measured. In total, 279 participants with schizophrenia were recruited. The overall incidences of hyperprolactinemia, sexual dysfunction, and metabolic syndrome were 51.6, 53.8, and 43.7%, respectively. Higher ASEX scores, higher insulin levels, female sex, and younger age were associated with hyperprolactinemia. Prolactin level was significantly correlated with ASEX score. Elevated prolactin levels, concomitant antidepressant, increased insulin resistance, longer illness duration, and female sex were associated with sexual dysfunction. Female participants recorded higher levels of sexual dysfunction than their male counterparts did, whereas male participants had comparatively lower prolactin levels and lower rates of spousal partnership. Hyperprolactinemia, metabolic syndrome, and sexual dysfunction are prevalent in patients with schizophrenia treated with olanzapine. Clinicians should maintain awareness of these problems and monitor them regularly with their patients.

Mechanisms Underlying the Comorbidity of Schizophrenia and Type 2 Diabetes Mellitus

The mortality rate of patients with schizophrenia is high, and life expectancy is shorter by 10 to 20 years. Metabolic abnormalities including type 2 diabetes mellitus (T2DM) are among the main reasons. The prevalence of T2DM in patients with schizophrenia may be epidemiologically frequent because antipsychotics induce weight gain as a side effect and the cognitive dysfunction of patients with schizophrenia relates to a disordered lifestyle, poor diet, and low socioeconomic status. Apart from these common risk factors and risk factors unique to schizophrenia, accumulating evidence suggests the existence of common susceptibility genes between schizophrenia and T2DM. Functional proteins translated from common genetic susceptibility genes are known to regulate neuronal development in the brain and insulin in the pancreas through several common cascades. In this review, we discuss common susceptibility genes, functional cascades, and the relationship between schizophrenia and T2DM. Many genetic and epidemiological studies have reliably associated the comorbidity of schizophrenia and T2DM, and it is probably safe to think that common cascades and mechanisms suspected from common genes' functions are related to the onset of both schizophrenia and T2DM. On the other hand, even when genetic analyses are performed on a relatively large number of comorbid patients, the results are sometimes inconsistent, and susceptibility genes may carry only a low or moderate risk. We anticipate future directions in this field.

The prevalence, risk factors and clinical correlates of diabetes mellitus in Chinese patients with schizophrenia

Diabetes is one of the most common comorbid diseases in patients with schizophrenia. The present study examined the prevalence of diabetes and its clinical correlates in a large sample of Chinese patients with schizophrenia, which has not been examined systemically. In this cross-sectional study, a total of 1189 patients (males/females = 938/251; average age: 48.51 ± 10.09 years) were recruited. Fasting blood samples were collected to diagnose diabetes. Psychiatric symptoms were measured with the Positive and Negative Syndrome Scale (PANSS). The prevalence of diabetes was 12.53% with a significant gender difference (males: 10.87% versus females: 18.73%). Compared to patients without diabetes, those with diabetes were older, had a later age of onset, had a higher BMI, had higher positive symptom scores and had higher level of metabolic indices, including triglyceride, cholesterol and HDL cholesterol. After stepwise binary logistic regression analysis, age, BMI, and triglyceride level remained significantly associated with diabetes. This study suggests that diabetes occur with high prevalence in Chinese schizophrenia patients. In addition, age, BMI, and triglyceride level possibly are useful markers predicting an increased risk for diabetes.

Dopamine D4 receptor protected against hyperglycemia-induced endothelial dysfunction via PI3K /eNOS pathway

Hyperglycemia-induced endothelial dysfunction is generally believed to be the basis of diabetic vascular complications. Dopamine receptors is known to play an important protective role in diabetes. However, the protective effect of dopamine receptors against hyperglycemia-induced endothelial damage in diabetic rats is still unknown. In the present study, we established a cell model of hyperglycemia-induced endothelial dysfunction by treating human umbilical vein endothelial cells (HUVEC) with high glucose. MTT and lactate dehydrogenase assays results showed that high glucose treatment significantly reduced the cell viability and down-regulated dopamine D₄ receptor. Pre-treatment with PD168077, a specific D₄ receptor agonist, greatly improved endothelial cell viability and decreased apoptosis. Furthermore, pharmacological inhibition of phosphoinositide 3-kinase (PI3K) and endothelial nitric oxide synthase (eNOS) eliminated the protective effect of D₄ receptor against endothelial injury. More importantly, the expression level of D₄ receptor was also dramatically down-regulated in the arterial endothelium of rats with streptozotocin-(STZ)-induced diabetes, and the STZ-induced impairment of acetylcholine-induced vasodilation was reversed by activation of D₄ receptor. In conclusion, our results indicated that dopamine D₄ receptor protected against hyperglycemia-induced endothelial dysfunction via the PI3K/eNOS pathway, which may provide a novel strategy in the treatment of diabetes.

Evaluation of screening for drug use using postmortem prolactin levels in serum and cerebrospinal fluid

Prolactin (PRL) levels can usually be controlled by PRL-inhibiting psychiatric drugs that include anti-dopamine agents. However, the use of dopamine (DA) antagonists may lead to hyperprolactinemia under certain clinical conditions. The aim of this study was to investigate postmortem PRL levels as potential markers of drug abuse, especially that of DA antagonists, in autopsy cases. We examined 121 autopsy cases, excluding cases involving acute hypoxia/ischemia, such as asphyxia, because PRL concentrations are reportedly increased under acute hypoxic conditions. Detected drugs were classified as either DA antagonists, stimulants, psychotropic drugs other than DA antagonists, or other non-psychotropic drugs, and many cases had no detected drugs. Samples comprised blood collected from the right heart chamber and cerebrospinal fluid (CSF). PRL protein level was measured by chemiluminescent immunoassay, and PRL gene expression in the anterior pituitary of autopsy cases was analyzed by reverse transcription-polymerase chain reaction. The PRL-positive cell ratio in the anterior pituitary gland was also measured by immunohistochemical analysis. The results indicated that PRL levels in the serum and CSF were higher in DA antagonist cases than in other cases. PRL levels in the serum and CSF also correlated with the PRL gene expression in cases with abuse of DA antagonists. However, no significant difference in the PRL-positive cell ratio in the anterior pituitary gland was evident between any of the classes of drug-detected and drug-undetected cases. These results suggest that postmortem measurements of PRL transcription levels may be useful for diagnosing cases of DA antagonist use.

Co-shared genetics and possible risk gene pathway partially explain the comorbidity of schizophrenia, major depressive disorder, type 2 diabetes, and metabolic syndrome

Schizophrenia (SCZ) and major depressive disorder (MDD) in treatment-naive patients are associated with increased risk for type 2 diabetes (T2D) and metabolic syndrome (MetS). SCZ, MDD, T2D, and MetS are often comorbid and their comorbidity increases cardiovascular risk: Some risk genes are likely co-shared by them. For instance, transcription factor 7-like 2 (TCF7L2) and proteasome 26S subunit, non-ATPase 9 (PSMD9) are two genes independently reported as contributing to T2D and SCZ, and PSMD9 to MDD as well. However, there are scarce data on the shared genetic risk among SCZ, MDD, T2D, and/or MetS. Here, we briefly describe T2D, MetS, SCZ, and MDD and their genetic architecture. Next, we report separately about the comorbidity of SCZ and MDD with T2D and MetS, and their respective genetic overlap. We propose a novel hypothesis that genes of the prolactin (PRL)-pathway may be implicated in the comorbidity of these disorders. The inherited predisposition of patients with SCZ and MDD to psychoneuroendocrine dysfunction may confer increased risk of T2D and MetS. We illustrate a strategy to identify risk variants in each disorder and in their comorbid psychoneuroendocrine and mental-metabolic dysfunctions, advocating for studies of genetically homogeneous and phenotype-rich families. The results will guide future studies of the shared predisposition and molecular genetics of new homogeneous endophenotypes of SCZ, MDD, and metabolic impairment.

Hyperprolactinemia and insulin resistance in drug naive patients with early onset first episode psychosis

BACKGROUND

Hyperprolactinemia and glucose and lipid metabolism abnormalities are often found in patients with schizophrenia and are generally considered secondary to the use of antipsychotic drugs. More recent studies have shown these same neuroendocrine and metabolic abnormalities in antipsychotic naïve patients with first episode psychosis (FEP), rising the hypothesis that schizophrenia itself may be related to an abnormal regulation of prolactin secretion and to impaired glucose tolerance. The aim of this study was to compare prolactin levels, glycometabolism parameters and lipid profile between a sample of 31 drug-naive adolescents in the acute phase of FEP and a control group of 23 subjects at clinical high risk (CHR) of developing psychosis.

METHODS

The assessment involved anthropometric data (weight, height, BMI index, pubertal stage) and blood tests (levels of glucose, glycated hemoglobin, serum insulin, triglycerides, total and fractionated cholesterol, prolactin). Insulin resistance (IR) was calculated through the homeostatic model of assessment (HOMA-IR), assuming a cut-off point of 3.16 for adolescent population. FEP patients and CHR controls were compared by using Student's t-distribution (t-test) for parametric data. P < 0.05 was considered significant.

RESULTS

Significant higher level of prolactin was found in FEP group than in CHR group (mean = 28.93 ± 27.16 vs 14.29 ± 7.86, P = 0.009), suggesting a condition of hyperprolactinemia (HPRL). Patients with FEP were more insulin resistant compared to patients at CHR, as assessed by HOMA-IR (mean = 3.07 ± 1.76 vs 2.11 ± 1.11, P = 0.043). Differences of fasting glucose (FEP = 4.82 ± 0.71, CHR = 4.35 ± 0.62, P = 0.016) and HbA1c (FEP = 25.86 ± 13.31, CHR = 33.00 ± 2.95, P = 0.013), were not clinically significant as the mean values were within normal range for both groups. No significant differences were found for lipid profile. A BMI value within the range of normal weight was found for both groups, with no significant differences.

CONCLUSION

We suggested that HPRL, increase in HOMA-IR, and psychotic symptoms may be considered different manifestations of the acute onset of schizophrenia spectrum psychosis, with a common neurobiological vulnerability emerging since adolescence. The influence of age and gender on clinical manifestations of psychotic onset should be considered for early prevention and treatment of both schizophrenia spectrum psychosis and neuroendocrine-metabolic dysfunctions.

Prolactin selectively transported to cerebrospinal fluid from blood under hypoxic/ischemic conditions

Aim

The aim of this study was to determine and to verify the correlation between the amount of prolactin (PRL) levels in the blood and in the cerebrospinal fluid (CSF) by various causes of death as an indicator for acute hypoxia in autopsy cases. It is to confirm the cause of the change in prolactin level in CSF by in vitro system.

Materials and methods

In autopsy materials, the PRL levels in blood from the right heart ventricle and in the CSF were measured by chemiluminescent enzyme immunoassay, and changes in the percentage of PRL-positive cells in the pituitary gland were examined using an immunohistochemical method. Furthermore, an inverted culture method was used as an in vitro model of the blood-CSF barrier using epithelial cells of the human choroid plexus (HIBCPP cell line) and SDR-P-1D5 or MSH-P3 (PRL-secreting cell line derived from miniature swine hypophysis) under normoxic or hypoxic (5% oxygen) conditions, and as an index of cell activity, we used Vascular Endothelial Growth Factor (VEGF).

Results and discussion

Serum PRL levels were not significantly different between hypoxia/ischemia cases and other causes of death. However, PRL levels in CSF were three times higher in cases of hypoxia/ischemia than in those of the other causes of death. In the cultured cell under the hypoxia condition, PRL and VEGF showed a high concentration at 10 min. We established a brain-CSF barrier model to clarify the mechanism of PRL transport to CSF from blood, the PRL concentrations from blood to CSF increased under hypoxic conditions from 5 min. These results suggested that PRL moves in CSF through choroidal epithelium from blood within a short time. PRL is hypothesized to protect the hypoxic/ischemic brain, and this may be because of the increased transportation of the choroid plexus epithelial cells.

Early Combination Therapy for Type 2 Diabetes Mellitus and Common Comorbid Mental Disorders

The relationship between type 2 diabetes mellitus and antipsychotic use by schizophrenia patients is recognized but not well understood. This article reviews the literature regarding metabolic interactions, pathological pathways, and protocols for screening, monitoring, and using combination therapy for individuals with type 2 diabetes mellitus and common comorbid mental health conditions. Because primary care physicians manage patients with both mental and general medical illnesses, such as diabetes, understanding their perspectives on the challenges and facilitators of the care of these patients is critical to improving clinical outcomes. Although the relationship between type 2 diabetes mellitus and antipsychotic use by schizophrenia patients has been recognized, clinical guidelines for their treatment are not recent. Individuals with mental disorders present a vulnerable population with high medical needs that are often mistreated or missed. Given the significant contribution of metabolic syndrome and comorbid diabetes mellitus to morbidity and mortality of such patients, ongoing primary care should be coordinated between general practitioners and mental health professionals to prevent serious complications and adverse medication side effects.

The Obesity-Impulsivity Axis: Potential Metabolic Interventions in Chronic Psychiatric Patients

Pathological impulsivity is encountered in a broad range of psychiatric conditions and is thought to be a risk factor for aggression directed against oneself or others. Recently, a strong association was found between impulsivity and obesity which may explain the high prevalence of metabolic disorders in individuals with mental illness even in the absence of exposure to psychotropic drugs. As the overlapping neurobiology of impulsivity and obesity is being unraveled, the question asked louder and louder is whether they should be treated concomitantly. The treatment of obesity and metabolic dysregulations in chronic psychiatric patients is currently underutilized and often initiated late, making correction more difficult to achieve. Addressing obesity and metabolic dysfunction in a preventive manner may not only lower morbidity and mortality but also the excessive impulsivity, decreasing the risk for aggression. In this review, we take a look beyond psychopharmacological interventions and discuss dietary and physical therapy approaches.

Metabolic pathways in the periphery and brain: Contribution to mental disorders?

The association between mental disorders and diabetes has a long history. Recent large-scale, well-controlled epidemiological studies confirmed a link between diabetes and psychiatric illnesses. The scope of this review is to summarize our current understanding of this relationship from a molecular perspective. We first discuss the potential contribution of diabetes-associated metabolic impairments to the etiology of mental conditions. Then, we focus on possible shared molecular risk factors and mechanisms. Simple comorbidity, shared susceptibility loci, and common pathophysiological processes in diabetes and mental illnesses have changed our traditional way of thinking about mental illness. We conclude that schizophrenia and affective disorders are not limited to an imbalance in dopaminergic and serotoninergic neurotransmission in the brain. They are also systemic disorders that can be considered, to some extent, as metabolic disorders.