Hypothalamic serotonin-insulin signaling cross-talk and alterations in a type 2 diabetic model

Impact of Serotonin Transporter Absence on Brain Insulin Receptor Expression, Plasma Metabolome Changes, and ADHD-like Behavior in Mice fed a Western Diet

The impaired function of the serotonin transporter (SERT) in humans has been linked to a higher risk of obesity and type 2 diabetes, especially as people age. Consuming a "Western diet" (WD), which is high in saturated fats, cholesterol, and sugars, can induce metabolic syndrome. Previous research indicated that mice carrying a targeted inactivation of the Sert gene (knockout, KO) and fed a WD display significant metabolic disturbances and behaviors reminiscent of ADHD. These abnormalities might be mediated via a dysfunction in insulin receptor (IR) signaling, which is also associated with adult ADHD. However, the impact of Sert deficiency on IR signaling and systemic metabolic changes has not been thoroughly explored. In this study, we conducted a detailed analysis of locomotor behavior in wild-type (WT) and KO mice fed a WD or control diet. We investigated changes in the blood metabolome and examined, via PCR, the expression of insulin receptor A and B isoforms and key regulators of their function in the brain. Twelve-month-old KO mice and their WT littermates were fed a WD for three weeks. Nuclear magnetic resonance spectroscopy analysis of plasma samples showed that KO mice on a WD had higher levels of lipids and lipoproteins and lower levels of glucose, lactate, alanine, valine, and isoleucine compared to other groups. SERT-KO mice on the control diet exhibited increased brain levels of both IR A and B isoforms, accompanied by a modest increase in the negative regulator ENPP. The KO mice also displayed anxiety-like behavior and reduced exploratory activity in an open field test. However, when the KO animals were fed a WD, the aberrant expression levels of IR isoforms in the KO mice and locomotor behavior were ameliorated indicating a complex interaction between genetic and dietary factors that might contribute to ADHD-like symptoms. Overall, our findings suggest that the lack of Sert leads to a unique metabolic phenotype in aged mice, characterized by dysregulated IR-related pathways. These changes are exacerbated by WD in the blood metabolome and are associated with behavioral abnormalities.

Insulin modulates emotional behavior through a serotonin-dependent mechanism

Type-2 Diabetes (T2D) is characterized by insulin resistance and accompanied by psychiatric comorbidities including major depressive disorders (MDD). Patients with T2D are twice more likely to suffer from MDD and clinical studies have shown that insulin resistance is positively correlated with the severity of depressive symptoms. However, the potential contribution of central insulin signaling in MDD in patients with T2D remains elusive. Here we hypothesized that insulin modulates the serotonergic (5-HT) system to control emotional behavior and that insulin resistance in 5-HT neurons contributes to the development of mood disorders in T2D. Our results show that insulin directly modulates the activity of dorsal raphe (DR) 5-HT neurons to dampen 5-HT neurotransmission through a 5-HT1A receptor-mediated inhibitory feedback. In addition, insulin-induced 5-HT neuromodulation is necessary to promote anxiolytic-like effect in response to intranasal insulin delivery. Interestingly, such an anxiolytic effect of intranasal insulin as well as the response of DR 5-HT neurons to insulin are both blunted in high-fat diet-fed T2D animals. Altogether, these findings point to a novel mechanism by which insulin directly modulates the activity of DR 5-HT neurons to dampen 5-HT neurotransmission and control emotional behaviors, and emphasize the idea that impaired insulin-sensitivity in these neurons is critical for the development of T2D-associated mood disorders.

Migraine, Brain Glucose Metabolism and the "Neuroenergetic" Hypothesis: A Scoping Review

Increasing evidence suggests that migraine may be the result of an impaired brain glucose metabolism. Several studies have reported brain mitochondrial dysfunction, impaired brain glucose metabolism and gray matter volume reduction in specific brain areas of migraineurs. Furthermore, peripheral insulin resistance, a condition demonstrated in several studies, may extend to the brain, leading to brain insulin resistance. This condition has been proven to downregulate insulin receptors, both in astrocytes and neurons, triggering a reduction in glucose uptake and glycogen synthesis, mainly during high metabolic demand. This scoping review examines the clinical, epidemiologic and pathophysiologic data supporting the hypothesis that abnormalities in brain glucose metabolism may generate a mismatch between the brain's energy reserve and metabolic expenditure, triggering migraine attacks. Moreover, alteration in glucose homeostasis could generate a chronic brain energy deficit promoting migraine chronification. Lastly, insulin resistance may link migraine with its comorbidities, like obesity, depression, cognitive impairment and cerebrovascular diseases. PERSPECTIVE: Although additional experimental studies are needed to support this novel "neuroenergetic" hypothesis, brain insulin resistance in migraineurs may unravel the pathophysiological mechanisms of the disease, explaining the migraine chronification and connecting migraine with comorbidities. Therefore, this hypothesis could elucidate novel potential approaches for migraine treatment.

The impact of dietary macronutrient intake on cognitive function and the brain

Macronutrients - carbohydrates, fats, and proteins - supply the nutrients required for optimal functioning. Inadequate intake compromises both physical and brain health. We synthesized research on macronutrients from whole meals on cognitive function in healthy adults and identified underlying mechanisms. Intake of simple carbohydrates ('sugars') is consistently associated with decreased global cognition whereas consumption of complex carbohydrates correlates with successful brain aging and improved memory both in the short- and long-term. Saturated fatty acid intake correlates with decreased memory and learning scores whereas omega-3 intake correlates positively with memory scores. Protein intake boosts executive function and working memory when task-demands are high. Individual differences affecting the macronutrient-cognition relationship are age, physical activity, and glucose metabolism. Neural correlates reflect findings on cognitive functions: cortical thickness and cerebral amyloid burden correlate with sugar intake, inflammatory status and cerebral glucose metabolism correlate with fatty acid intake. Key mechanisms by which dietary macronutrients affect the brain and cognition include glucose and insulin metabolism, neurotransmitter actions, and cerebral oxidation and inflammation. In conclusion, macronutrient intake affects cognitive function both acutely and in the long-term, involving peripheral and central mechanisms. A healthy diet supports brain integrity and functionality, whereas inadequate nutrition compromises it. Studying diet can be key to nutritional recommendations, thereby improving the landscape of mental health and healthy brain aging.

Resveratrol Affects Insulin Signaling in Type 2 Diabetic Goto-Kakizaki Rats

Resveratrol is a biologically active diphenolic compound exerting multiple beneficial effects in the organism, including anti-diabetic properties. This action is, however, not fully elucidated. In the present study, we examined effects of resveratrol on some parameters related to insulin signaling, and also on diabetes-associated dysregulation in Goto-Kakizaki (GK) rats with congenital type 2 diabetes. Resveratrol was given at the dose of 20 mg/kg b.w. for 10 weeks. It was shown that the expression and phosphorylation levels of insulin receptor in the skeletal muscle of GK rats were significantly decreased, compared with control animals. However, these changes were totally prevented by resveratrol. Liver expression of the insulin receptor was also reduced, but in this case, resveratrol was ineffective. Resveratrol was also demonstrated to significantly influence parameters of insulin binding (dissociation constant and binding capacity) in the skeletal muscle and liver. Moreover, it was shown that the expression levels of proteins related to intracellular glucose transport (GLUT4 and TUG) in adipose tissue of GK rats were significantly decreased. However, treatment with resveratrol completely abolished these changes. Resveratrol was found to induce normalization of TUG expression in the skeletal muscle. Blood levels of insulin and GIP were elevated, whereas proinsulin and GLP-1 diminished in GK rats. However, concentrations of these hormones were not affected by resveratrol. These results indicate that resveratrol partially ameliorates diabetes-associated dysregulation in GK rats. The most relevant finding covers the normalization of the insulin receptor expression in the skeletal muscle and also GLUT4 and TUG in adipose tissue.

Bibliometrics Analysis of the Research Status and Trends of the Association Between Depression and Insulin From 2010 to 2020

Depression is one of the common mental illnesses. Because it is an important complication of diabetes, its association with changes in insulin levels and insulin resistance, the causative factors of diabetes, has attracted widespread attention. However, the association between insulin and depression has not been systematically studied through bibliometric and visual analysis. This study is based on 3131 publications of Web of Science to identify the current research status and research trends in this field. The results show that since 2010, the number of publications has been growing rapidly. Cooperative network analysis shows that the United States, the University of Toronto and Roger S Mcintyre are the most influential countries, research institutes and scholars, respectively. Insulin resistance, obesity, and metabolic syndrome are hot topics in this field. Analysis of keywords and references reveals that "sex hormones," is new research area that constantly emerging. As far as we know, this study is the first one to visualize the association between depression and insulin and predict potential future research trends through bibliometric and visual analysis.

Effects of Resveratrol in Goto-Kakizaki Rat, a Model of Type 2 Diabetes

Resveratrol exhibits a pleiotropic, favorable action under various pathological conditions, including type 2 diabetes. However, its anti-diabetic effects in animal models and human trials have not been fully elucidated. The aim of the present study was to determine whether resveratrol is capable of inducing beneficial changes in the Goto-Kakizaki rat, a spontaneous model of diabetes, which in several aspects is similar to type 2 diabetes in humans. Goto-Kakizaki (GK) rats and control Sprague–Dawley (SD) rats were treated intragastrically with resveratrol (20 mg/kg b.w./day) for 10 weeks. Then, a glucose tolerance test was performed and levels of some adipokines in blood were measured. Moreover, lipid contents in skeletal muscle and liver tissues, along with the expression and phosphorylation of pivotal enzymes (AMP—activated protein kinase—AMPK, acetyl-CoA carboxylase—ACC, protein kinase B—Akt) in these tissues were determined. Histology of pancreatic islets was also compared. GK rats non-treated with resveratrol displayed a marked glucose intolerance and had increased lipid accumulation in the skeletal muscle. Moreover, upregulation of the expression and phosphorylation of AMPK, ACC and Akt was shown in the muscle tissue of GK rats. Those rats also had an abnormal structure of pancreatic islets compared with control animals. However, treatment with resveratrol improved glucose tolerance and prevented lipid accumulation in the skeletal muscle of GK rats. This effect was associated with a substantial normalization of expression and phosphorylation of ACC and Akt. In GK rats subjected to resveratrol therapy, the structure of pancreatic islets was also clearly improved. Moreover, blood adiponectin and leptin levels were partially normalized by resveratrol in GK rats. It was revealed that resveratrol ameliorates key symptoms of diabetes in GK rats. This compound improved glucose tolerance, which was largely linked to beneficial changes in skeletal muscle. Resveratrol also positively affected pancreatic islets. Our new findings show that resveratrol has therapeutic potential in GK rats.

Cross-Talk Between Insulin Signaling and G Protein-Coupled Receptors

Diabetes is a major risk factor for the development of heart failure. One of the hallmarks of diabetes is insulin resistance associated with hyperinsulinemia. The literature shows that insulin and adrenergic signaling is intimately linked to each other; however, whether and how insulin may modulate cardiac adrenergic signaling and cardiac function remains unknown. Notably, recent studies have revealed that insulin receptor and β2 adrenergic receptor (β2AR) forms a membrane complex in animal hearts, bringing together the direct contact between 2 receptor signaling systems, and forming an integrated and dynamic network. Moreover, insulin can drive cardiac adrenergic desensitization via protein kinase A and G protein-receptor kinases phosphorylation of the β2AR, which compromises adrenergic regulation of cardiac contractile function. In this review, we will explore the current state of knowledge linking insulin and G protein-coupled receptor signaling, especially β-adrenergic receptor signaling in the heart, with emphasis on molecular insights regarding its role in diabetic cardiomyopathy.

Liver Illness and Psychiatric Patients

Patients with psychiatric disorders are usually more exposed to multiple somatic illnesses, including liver diseases. Specific links are established between psychiatric disorders and alcohol hepatitis, hepatitis B, and hepatitis C in the population as a whole, and specifically in drug abusers. Metabolic syndrome criteria, and associated steatosis or non-alcoholic steato-hepatitis (NASH) are frequent in patients with chronic psychiatric disorders under psychotropic drugs, and should be screened. Some psychiatric medications, such as neuroleptics, mood stabilizers, and a few antidepressants, are often associated with drug-induced liver injury (DILI). In patients with advanced chronic liver diseases, the prescription of some specific psychiatric treatments should be avoided. Psychiatric disorders can be a limiting factor in the decision-making and following up for liver transplantation.

Pharmacological approaches to the management of binge eating disorder

In the USA, binge eating disorder (BED) is the most common eating disorder, with a lifetime prevalence of ~3.5 % in adult women, 2.0 % in adult men, and 1.6 % in adolescents. BED is characterized by frequent episodes of binge eating that are accompanied by a sense of loss of control over eating and result in marked psychological distress. BED is highly co-morbid with obesity and with depression and other psychiatric conditions, and it is associated with substantial role impairment. Currently, there are no US FDA-approved pharmacological treatments for BED. Animal and human studies implicate underlying dysregulation in dopamine, opioid, acetylcholine, and serotonin neurocircuitry within brain reward regions in the pathogenesis and maintenance of BED. To date, the efficacy of various agents that target these and other neurotransmitter systems involved in motivated feeding behavior, mood regulation, and impulse control have been investigated in the treatment of BED. Several antidepressant and anticonvulsant agents have demonstrated efficacy in reducing binge eating frequency, but only in limited cases have these effects resulted in patients achieving abstinence, which is the primary goal of treatment; they also range from less (fluvoxamine) to more (topiramate) effective in achieving weight loss that is both clinically meaningful and significantly greater than placebo. Collectively, the literature on pharmacological treatment approaches to BED is limited in that very few agents have been studied in multiple, confirmatory trials with adequate follow up, and almost none have been evaluated in large patient samples that are diverse with respect to age, sex, and ethnicity. In addition, prior trials have not adequately addressed, through study design, the high placebo response commonly observed in this patient population. Several novel agents are in various phases of testing, and recent animal studies focusing on glutamate-signaling circuits linking the amygdala to the lateral hypothalamus offer new avenues for exploration and potential therapeutic development. Studies of newly FDA-approved medications for long-term obesity treatment and further explorations of dietary supplements and neutraceuticals with appetite- and mood-altering properties may also be worthwhile.

Dietary chromium supplementation for targeted treatment of diabetes patients with comorbid depression and binge eating

Dietary chromium supplementation for the treatment of diabetes remains controversial. The prevailing view that chromium supplementation for glucose regulation is unjustified has been based upon prior studies showing mixed, modest-sized effects in patients with type 2 diabetes (T2DM). Based on chromium's potential to improve insulin, dopamine, and serotonin function, we hypothesize that chromium has a greater glucoregulatory effect in individuals who have concurrent disturbances in dopamine and serotonin function--that is, complex patients with comorbid diabetes, depression, and binge eating. We propose, as suggested by the collective data to date, the need to go beyond the "one size fits all" approach to chromium supplementation and put forth a series of experiments designed to link physiological and neurobehavioral processes in the chromium response phenotype.

Hypothalamic differences in expression of genes involved in monoamine synthesis and signaling pathways after insulin injection in chickens from lines selected for high and low body weight

Long-term selection for juvenile body weight from a common founder population resulted in two divergent chicken lines (low-weight selected line (LWS), high-weight selected line (HWS)) that display distinct food intake and blood glucose responses to exogenous neuropeptides and insulin. The objective of this study was to elucidate putative targets affecting food intake and energy homeostasis by sequencing hypothalamic RNA from LWS and HWS chickens after insulin injection. Ninety-day-old female LWS and HWS chickens were injected with either vehicle or insulin and hypothalamus collected at 1 h postinjection. Through RNA sequencing, a total of 361 differentially expressed genes (DEGs) were identified. There was greater expression of genes, mainly tyrosine hydroxylase (TH), L-aromatic amino acid decarboxylase (DDC), and vesicular monoamine transporter (VMAT), involved in serotonin and dopamine biosynthesis and signaling in LWS than in HWS vehicle-injected chickens. In contrast, after insulin injection, these genes were more highly expressed in HWS than in LWS. We identified 90 single nucleotide polymorphisms (SNPs) existing only in the HWS and 121 SNPs specific to LWS and 5119 SNPs close to fixation (with absolute frequency difference ≥0.9). Four were located in genes encoding enzymes associated with serotonergic and dopaminergic pathways, such as DDC, TH, and solute carrier family 18, member 2 (VMAT). These data implicate differences in biogenic amines such as serotonin and dopamine in hypothalamic physiology between the chicken lines, and these differences might be associated with polymorphisms during long-term selection. Changes in serotonergic and dopaminergic signaling pathways in response to insulin injection suggest a role in whole-body energy homeostasis.

Hippocampal GSK3β as a Molecular Link Between Obesity and Depression

Obesity is considered as a risk factor for mood disorders including depression. Nevertheless, the mechanisms underlying this association are not clearly understood. To address this issue, we investigated the impact of high-fat (HF)-diet-induced obesity on depressive-like behavior and on serotonin (5-HT)-dependent Akt/glycogen synthase kinase 3β (GSK3β) signaling in the dentate gyrus (DG) of the hippocampus, which has been associated with mood regulation. We first showed that a HF diet induced significant overweight and hyperglycemia as well as a depressive-like behavior in adult Wistar rats. By using an ex vivo approach on brain slices, we demonstrated that 5-HT activates the Akt/GSK3β cascade in the DG of control chow (C) diet-fed animals and that a 16-week HF diet feeding abolishes this activation, concurrently with a desensitization of leptin and insulin signaling in the same region. Furthermore, depressive-like behavior inversely correlated with 5-HT-induced phosphorylation of GSK3β in the subgranular neurons of the DG. Interestingly, a substitution of HF with C diet for 6 weeks induced a total loss of depressive symptoms, whereas body weight and glycemia remained significantly higher compared to control rats. In addition, food restoration led to a recovery of the Akt/GSK3β signaling pathway activation in the DG. In parallel, we observed a negative correlation between body weight and cell proliferation in the subgranular zone of the DG. To conclude, we provide evidence for a desensitization of 5-HT-induced Akt/GSK3β signaling and an impaired cell proliferation in the DG by HF diet, suggesting novel molecular mechanisms linking obesity to depression.

Green tea extract improves high fat diet-induced hypothalamic inflammation, without affecting the serotoninergic system

To investigate possible mechanisms of green tea's anti-obesity and anti-diabetic effects in the hypothalamus, the central regulator of metabolism, of mice fed with high-fat diet (HFD), we analyzed proteins of the toll-like receptor 4 (TLR4) pathway and serotoninergic proteins involved in energy homeostasis. Thirty-day-old male Swiss mice were fed with HFD rich in saturated fat and green tea extract (GTE) for 8 weeks. After that, body weight and mass of fat depots were evaluated. Oral glucose tolerance test was performed 3 days prior to euthanasia; serum glucose, insulin and adiponectin were measured in fasted mice. Hypothalamic TLR4 pathway proteins, serotonin receptors 1B and 2C and serotonin transporter were analyzed by Western blotting or enzyme-linked immunosorbent assay. A second set of animals was used to measure food intake in response to fluoxetine, a selective serotonin reuptake inhibitor. Mice fed with HFD had increased body weight and mass of fat depots, impaired oral glucose tolerance, elevated glucose and insulin and decreased adiponectin serum levels. TLR4, IκB-α, nuclear factor κB p50 and interleukin 6 were increased by HFD. Concomitant GTE treatment ameliorated these parameters. The serotoninergic system remained functional after HFD treatment despite a few alterations in protein content of serotonin receptors 1B and 2C and serotonin transporter. In summary, the GTE attenuated the deleterious effects of the HFD investigated in this study, partially due to reduced hypothalamic inflammation.

Serotonin and the bone assessment

INTRODUCTION

Lately, the in vitro and in vivo studies on serotonin metabolism have been pointing its influence in bone health. Also, there are no particular recommendations in performing the serum serotonin assessment in order to evaluate the skeletal status.

AIM

We aimed to correlate the bone turnover markers and lumbar bone mineral density (BMD) with serotonin.

MATERIAL AND METHODS

There is a cross-sectional study in Caucasian postmenopausal women. They were not diagnosed with carcinoid syndrome, or bone anomalies, and received no treatment (including antiresorptives). The following bone formation markers were performed: serum alkaline phosphatase (AP), serum osteocalcin (OC), and the bone resorption marker: serum CrossLaps (CL). Serum serotonin (high-pressure liquid chromatography), as well as central DXA (GE Prodigy) were assessed.

RESULTS

191 women of 57.1 years mean age were grouped according to DXA (WHO criteria). The linear regression analysis between serum serotonin and CL were not statistically significant (SS), between serotonin and OC was SS in the newly diagnosed osteoporosis group (N=40, r=0.4, p=0.03), between serotonin and AP SS was found in osteopenia group (N=88, r=0.24, p=0.03), with no changes when adjusting for age and BMI. The partial correlation between serotonin and BMD was not SS.

DISCUSSION

The study raises the question of serotonin as a bone metabolism marker seeing that the results were not consistent. The main limit of our study was that we did not analyze the possible use of antidepressants to these women. Overall, this was a pilot study in clinical practice where few reports have been published, but still necessary, because the use of serum serotonin in current skeletal evaluation is still unclear.

Neuronal ablation of p-Akt at Ser473 leads to altered 5-HT1A/2A receptor function

The serotonergic system regulates a wide range of behavior, including mood and impulsivity, and its dysregulation has been associated with mood disorders, autism spectrum disorder, and addiction. Diabetes is a risk factor for these conditions. Insulin resistance in the brain is specifically associated with susceptibility to psychostimulant abuse. Here, we examined whether phosphorylation of Akt, a key regulator of the insulin signaling pathway, controls serotonin (5-HT) signaling. To explore how impairment in Akt function regulates 5-HT homeostasis, we used a brain-specific rictor knockout (KO) mouse model of impaired neuronal phosphorylation of Akt at Ser473. Cortical 5-HT1A and 5-HT2A receptor binding was significantly elevated in rictor KO mice. Concomitant with this elevated receptor expression, the 5-HT1A receptor agonist 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) led to an increased hypothermic response in rictor KO mice. The increased cortical 5-HT1A receptor density was associated with higher 5-HT1A receptor levels on the cortical cell surface. In contrast, rictor KO mice displayed significantly reduced head-twitch response (HTR) to the 5-HT2A/C agonist 2,5-dimethoxy-4-iodoamphetamine (DOI), with evidence of impaired 5-HT2A/C receptor signaling. In vitro, pharmacological inhibition of Akt significantly increased 5-HT1A receptor expression and attenuated DOI-induced 5-HT2A receptor signaling, thereby lending credence to the observed in vivo cross-talk between neuronal Akt signaling and 5-HT receptor regulation. These data reveal that defective central Akt function alters 5-HT signaling as well as 5-HT-associated behaviors, demonstrating a novel role for Akt in maintaining neuronal 5-HT receptor function.

The functional state of hormone-sensitive adenylyl cyclase signaling system in diabetes mellitus

Diabetes mellitus (DM) induces a large number of diseases of the nervous, cardiovascular, and some other systems of the organism. One of the main causes of the diseases is the changes in the functional activity of hormonal signaling systems which lead to the alterations and abnormalities of the cellular processes and contribute to triggering and developing many DM complications. The key role in the control of physiological and biochemical processes belongs to the adenylyl cyclase (AC) signaling system, sensitive to biogenic amines and polypeptide hormones. The review is devoted to the changes in the GPCR-G protein-AC system in the brain, heart, skeletal muscles, liver, and the adipose tissue in experimental and human DM of the types 1 and 2 and also to the role of the changes in AC signaling in the pathogenesis and etiology of DM and its complications. It is shown that the changes of the functional state of hormone-sensitive AC system are dependent to a large extent on the type and duration of DM and in experimental DM on the model of the disease. The degree of alterations and abnormalities of AC signaling pathways correlates very well with the severity of DM and its complications.

The polymorphism in the let-7 targeted region of the Lin28 gene is associated with increased risk of type 2 diabetes mellitus

Genetic polymorphisms in the miRNAs pathway of the pathogenesis of disease might contribute to the risk of disease. However, it is unclear whether these polymorphisms about miRNAs are associated with the risk of type 2 diabetes mellitus (T2DM). We performed a case-control study to investigate two polymorphisms in the let-7/Lin28 pathway based on 588 T2DM patients and 588 age and sex matched controls. The results showed that the rs3811463 polymorphism was associated with increased risk of T2DM (odds ratio (OR)=1.47, 95% confidence inference (95%CI)=1.13-1.93, P=0.005), while the rs3811464 not (OR=1.04, 95%CI=0.79-1.36, P=0.78). For the rs3811463 polymorphism, the variant genotypes were associated with increased risk of disease in females; statistically differences were observed in the clinical features of age at diagnosis, hypertension and peripheral neuropathy for the variant and wild genotype of the rs3811463 in T2DM. In summary, the results indicated that the rs3811463 polymorphism in the let-7/Lin28 pathway could significantly increase the risk of T2DM.

Associations of depression, anxiety and antidepressants with histological severity of nonalcoholic fatty liver disease

BACKGROUND

Depression and anxiety are common in patients with nonalcoholic fatty liver disease (NAFLD). However, their associations with histological severity of NAFLD are unknown.

AIM

This study examined the association(s) of depression, anxiety and antidepressant pharmacotherapy with severity of histological features in patients with NAFLD.

METHODS

We analysed 567 patients with biopsy-proven NAFLD enrolled in the Duke NAFLD Clinical Database. Depressive and anxiety symptoms were assessed using the Hospital Anxiety & Depression Scale (HADS). The associations of depression and anxiety with severity of histological features of NAFLD were analysed using multiple logistic (or ordinal logistic) regression models with and without adjusting for confounding factors.

RESULT

Subclinical and clinical depression was noted in 53% and 14% of patients respectively. Subclinical and clinical anxiety was noted in 45% and 25% of patients respectively. After adjusting for confounders, depression was significantly associated with more severe hepatocyte ballooning in a dose-dependent manner (likelihood ratio test, P = 0.0201); adjusted cumulative odds ratio (COR) of subclinical and clinical depression for having a higher grade of hepatocyte ballooning were 2.1 [95% CI, 1.0, 4.4] and 3.6 [95% CI, 1.4, 8.8].

CONCLUSIONS

In patients with NAFLD, depression was associated with more severe hepatocyte ballooning. Further investigation exploring pathobiological mechanisms underlying the observed associations and potential effects of antidepressant pharmacotherapy on NAFLD liver histology is warranted.

A double-blind, randomized pilot trial of chromium picolinate for binge eating disorder: results of the Binge Eating and Chromium (BEACh) study

OBJECTIVE

Chromium treatment has been shown to improve mood, appetite, and glucose regulation in various psychiatric and medical patient populations. The authors propose that chromium may be useful in the treatment of binge eating disorder (BED).

METHOD

Twenty-four overweight adults with BED were enrolled in a 6-month double-blind placebo-controlled trial and randomly assigned to receive either 1000mcg chromium/day ("high dose"; n=8) or 600mcg chromium/day ("moderate dose"; n=9) as chromium picolinate or placebo (n=7). Mixed linear regression models were used to estimate mean change in binge frequency and related psychopathology, weight, symptoms of depression, and fasting glucose.

RESULTS

Fasting glucose was significantly reduced in both chromium groups compared to the placebo group; similarly, numerically, but not significantly, greater reductions in binge frequency, weight, and symptoms of depression were observed in those treated with chromium versus placebo, although statistical power was limited in this pilot trial. For fasting glucose, the findings suggest a dose response with larger effects in the high dose compared to moderate dose group.

CONCLUSION

These initial findings support further larger trials to determine chromium's efficacy in maintaining normal glucose regulation, reducing binge eating and related psychopathology, promoting modest weight loss, and reducing symptoms of depression in individuals with BED. Studies designed to link the clinical effects of chromium with changes in underlying insulin, serotonin, and dopamine pathways may be especially informative. If efficacious, chromium supplementation may provide a useful, low-cost alternative to or augmentation strategy for selective serotonin reuptake inhibitors, which have partial efficacy in BED. ClinicalTrials.gov NCT00904306.

The serotonin and the bone assessment

INTRODUCTION

Lately, the in vitro and in vivo studies on serotonin metabolism pointed their influence in bone health. In addition, there are no particular recommendations in performing the serum serotonin assessment in order to evaluate the skeletal status. Aim. We aimed to correlate the bone turnover markers and lumbar bone mineral density (BMD) with serotonin.

MATERIAL AND METHODS

There is a cross-sectional study in Caucasian postmenopausal women. They were not diagnosed with carcinoid syndrome, or bone anomalies, and received no treatment (including antiresorptives). We performed the bone formation markers: serum alkaline phosphatase (AP), serum osteocalcin (OC), and the bone resorption marker: serum CrossLaps (CL). Serum serotonin (high-pressure liquid chromatography), as well as central DXA (GE Prodigy) were assessed.

RESULTS

191 women of 57.1 years mean age were grouped according to DXA (WHO criteria). The linear regression analysis between serum serotonin and CL was not statistically significant (SS), between serotonin and OC was SS in the newly diagnosed osteoporosis group (N=40, r=0.4, p=0.03), between serotonin and AP we found SS in osteopenia group (N=88, r=0.24, p=0.03), with no changes when adjusting for age and BMI. The partial correlation between serotonin and BMD was not SS.

DISCUSSION

The study raises the question of serotonin as a bone metabolism marker seeing that the results were not consistent. The main limit of our study is that we did not analyze the possible use of antidepressants by these women. Overall, this is a pilot study in clinical practice in which few reports have been published yet, but still necessary because the use of serum serotonin in current skeletal evaluation is still unclear.

Serotonin and the regulation of mammalian energy balance

Maintenance of energy balance requires regulation of the amount and timing of food intake. Decades of experiments utilizing pharmacological and later genetic manipulations have demonstrated the importance of serotonin signaling in this regulation. Much progress has been made in recent years in understanding how central nervous system (CNS) serotonin systems acting through a diverse array of serotonin receptors impact feeding behavior and metabolism. Particular attention has been paid to mechanisms through which serotonin impacts energy balance pathways within the hypothalamus. How upstream factors relevant to energy balance regulate the release of hypothalamic serotonin is less clear, but work addressing this issue is underway. Generally, investigation into the central serotonergic regulation of energy balance has had a predominantly “hypothalamocentric” focus, yet non-hypothalamic structures that have been implicated in energy balance regulation also receive serotonergic innervation and express multiple subtypes of serotonin receptors. Moreover, there is a growing appreciation of the diverse mechanisms through which peripheral serotonin impacts energy balance regulation. Clearly, the serotonergic regulation of energy balance is a field characterized by both rapid advances and by an extensive and diverse set of central and peripheral mechanisms yet to be delineated.