Effects of olanzapine in male rats: enhanced adiposity in the absence of hyperphagia, weight gain or metabolic abnormalities

Exploring the therapeutic potential of chlorogenic acid in alleviating olanzapine-induced metabolic syndrome in rats: a key role of hypothalamic satiety proteins

Objectives: Olanzapine (Olz) is an effective antipsychotic medication for schizophrenia; however, its use is associated with weight gain and metabolic disorders. Chlorogenic acid (CGA), a dietary polyphenol, has a promising potential for the treatment of obesity, diabetes, and hypertension. This study aimed to determine whether CGA could effectively manage Olz-induced metabolic syndrome (MetS) in a rat model, with metformin (Met) as a positive control.Methods: Female Wistar rats were divided into seven groups: control; Olz (5 mg/kg/day, IP); CGA (20, 40, and 80 mg/kg/day, gavage) plus Olz; Met (100 mg/kg/day, gavage) plus Olz; and CGA (80 mg/kg/day, gavage) for 30 days. Metabolic parameters including body weight, fasting blood glucose, triglycerides, and blood pressure were assessed. This study focused on evaluating serum levels of leptin and adiponectin, as well as hypothalamic protein expression of pro-opiomelanocortin (POMC), neuropeptide Y (NPY), AMP-activated protein kinase (AMPK), and 5-HT2C receptors (5-HT2CR), which are known to influence energy balance and potentially play a role in Olz-induced metabolic abnormalities.Results: Olz caused substantial hyperphagia, weight gain, hypertension, and liver damage, along with elevated fasting blood glucose, triglycerides, and leptin levels. CGA and Met mitigated these effects, although Olz-induced elevation of adiponectin levels remained unaffected by either treatment. Mechanistically, Olz reduced 5-HT2CR protein levels, a trend that was observed in the CGA and Met therapy groups. Olz also enhanced NPY protein levels and the pAMPK/AMPK ratio while lowering POMC protein levels. These alterations were reversed in rats administered CGA or Met.Discussion: These findings suggest that CGA effectively attenuated the adverse metabolic consequences of Olz by modulating leptin, NPY, POMC, and AMPK protein levels. CGA's therapeutic potential highlights its potential as a dietary intervention for managing antipsychotic-induced metabolic disturbances.

Sex differences in effectiveness and adverse effects of mood stabilizers and antipsychotics: A systematic review

BACKGROUND

Psychiatric disorders differ in their prevalence, symptom profiles, and disease courses in men and women. However, sex differences in psychiatric disorders have not received enough attention to guide treatment recommendations. This systematic review aims to summarize sex differences in the treatment responses and adverse effects of mood stabilizers and antipsychotics transdiagnostically.

METHODS

We conducted a systematic review following the PRISMA 2020 statement (CRD42020212478). A literature search was conducted using MEDLINE, Embase, Cochrane Central, PsycINFO, Web of Science Core Collection, and Scopus databases. Studies comparing mood stabilizer or antipsychotic treatment outcomes in men and women were included. JBI critical appraisal checklists were used to assess bias risk.

RESULTS

Out of 4866 records, 129 reports (14 on mood stabilizers, 115 on antipsychotics) with varying designs were included. Sample sizes ranged from 17 to 22,774 participants (median = 147). The most common psychiatric diagnoses were schizophrenia spectrum (n = 109, 84.5 %) and bipolar disorders (n = 38, 29.5 %). Only four studies explored sex differences in mood stabilizer treatment response. In 40 articles on antipsychotic treatment response, 18 indicated no sex difference, while 16 showed females had better outcomes. Women had more adverse effects with both mood stabilizers and antipsychotics. The risk of bias was low in 84 (65.1 %) of studies.

LIMITATIONS

Substantial heterogeneity among the studies precluded performing a meta-analysis.

CONCLUSION

Number of studies focusing on sex differences in treatment outcomes of mood stabilizers is limited. Women may respond better to antipsychotics than men, but also experience more side effects. The impact of pharmacokinetics on sex differences warrants more attention.

Changes in hypothalamic mu-opioid receptor expression following acute olanzapine treatment in female rats: Implications for feeding behavior

Advances have been made in recent years in using opioid receptor antagonists as an adjunct therapy to psychotropic medication to reduce debilitating weight gain and metabolic adverse effects associated with in particular second generation antipsychotics. However, it is unknown whether second generation antipsychotics produce a change in opioid receptor expression in the brain. The present study investigated early changes in opioid receptor expression in the female rat hypothalamus, a master controller of hunger and metabolic regulation, after acute treatment with olanzapine, a commonly used second generation antipsychotic. Using quantitative spatial in situ hybridization and receptor autoradiography, expression levels of the three opioid receptors; kappa, mu and delta, were determined at mRNA and protein level, respectively, in the five hypothalamic areas: paraventricular nucleus, arcuate nucleus, ventromedial nucleus, dorsomedial nucleus and lateral hypothalamus. After 48 h of olanzapine treatment at clinically relevant plasma concentration weight gain and food intake changes, and increased plasma glucose were observed in female rats. Olanzapine treatment also led to a significant increase in mu opioid receptor availability in the arcuate nucleus, which contains both satiety and hunger controlling neurons. No other areas showed any opioid receptor expressional changes with olanzapine treatment on neither at mRNA nor protein level. Technical difficulties made it impossible to analyze mRNA levels in the lateral hypothalamus and overall binding of delta opioid receptors. Thus, the present study provided insights in to how olanzapine at clinically relevant plasma levels already at an early stage modulated the opioid system in the hypothalamus.

Antipsychotic Drug-Mediated Adverse Effects on Rat Testicles May Be Caused by Altered Redox and Hormonal Homeostasis

Sexual dysfunction, as a noticeable adverse effect of atypical antipsychotic drugs (APDs) for the treatment of schizophrenia, has not been investigated in detail. A study was undertaken to investigate whether 28-day long treatment with clozapine, ziprasidone or sertindole (using a recommended daily dose for atypical antipsychotic therapy), induced histopathological changes both in rat testicles and prostate, changed the activity of the antioxidant defence system and altered blood testosterone and prolactin. Clozapine, ziprasidone and sertindole induced histopathological changes in rat testicular tissue, which could be attributed to a disturbed testicular antioxidant defence system in addition to an altered prolactin to testosterone ratio. None of the APD treatments induced histopathological changes in prostate. Our results demonstrate that APDs have the capacity to change both redox and endocrinological balance. One or both outcomes could underline testicular degeneration and disturbed spermatogenesis.

Long-term effects of adolescent exposure to olanzapine in C57BL/6 J mice and the impact of dietary fish oil supplementation

RATIONALE

Second-generation antipsychotic (SGA) medications can produce abnormal weight gain and metabolic dysfunction in children, but little is known about the post-treatment consequences of adolescent SGA exposure.

OBJECTIVES

The objective of this study was to determine the long-term, post-treatment effects of adolescent olanzapine exposure on weight and metabolic function and whether dietary fish oil (FO) modulated any observed effects of olanzapine.

METHODS

Male and female mice were fed a high-fat, high-sugar (HF-HS) diet or an HF-HS diet supplemented with fish oil (HF-HS-FO) and were treated with olanzapine or vehicle for 29 days beginning on postnatal day 37.

RESULTS

In male mice, adolescent olanzapine treatment suppressed weight gain during and after treatment and improved metabolic function in adulthood; dietary fish oil reduced weight gain, increased expression of fatty acid oxidation genes, and decreased expression of genes associated with fatty acid synthesis and inflammation. In contrast, few effects were observed in female mice.

CONCLUSIONS

The current results suggest that adolescent olanzapine exposure can produce long-term alterations in weight and metabolic function in male mice and that dietary fish oil can reduce adverse effects of lifelong consumption of an HF-HS diet. Because expected adverse effects of adolescent olanzapine treatment were not observed, the potential beneficial effects of dietary fish oil for SGA-induced weight gain and metabolic dysfunction could not be evaluated.

Olanzapine induces weight gain in offspring of prenatally exposed poly I:C rats by reducing brown fat thermogenic activity

Background: Olanzapine (OLZ) is an antipsychotic with a high risk of metabolic syndrome, and its induced metabolic disturbance may be related to the thermogenic function of brown adipose tissue (BAT). Of note is that schizophrenia itself appears to be associated with a higher incidence of metabolic syndrome. However, whether OLZ affects metabolic disorders by regulating BAT function and its mechanism in animal models of schizophrenia have not been reported.

Methods: We induced maternal immune activation (MIA) in pregnant rodents by injection of synthetic double-stranded RNA-poly I:C (a virus-like substance), and rats were injected with poly I:C, 10 mg/kg) or saline on day 13 of gestation. Rat offspring received OLZ (1 mg/kg, tid) or vehicle from adulthood for 28 days, and body weight and food intake were recorded. Morphological alterations of white adipose tissue (WAT) and BAT were analyzed by HE and oil red staining, and expression of BAT-specific marker proteins/genes was detected by western blot and qRT-PCR. In addition, embryonic stem cells C3H10T1/2 were used to direct differentiation into brown-like adipocytes, and C3H10T1/2 cells were treated with OLZ for the differentiation process. The effects of OLZ on brown-like adipocyte differentiation and activity were analyzed using oil red staining, immunofluorescence and flow cytometry.

Results: Compared with the Veh (saline) group, the TG, pWAT weight, adipocyte size and liver weight of the Veh (poly I:C) group were significantly increased, suggesting that the offspring of Poly I:C rats had obvious dyslipidemia and lipid accumulation, which were risk factors for metabolic abnormalities such as obesity. In addition, OLZ treatment resulted in altered WAT and BAT morphology in poly I:C or saline exposed offspring, causing lipid accumulation and weight gain and reducing the expression of the BAT-specific marker molecule UCP1 protein/gene. At the same time, OLZ inhibited the directional differentiation and mitochondrial activity of C3H10T1/2 brown-like adipocytes.

Conclusion: Poly I:C-elicited MIA and OLZ differentially inhibited BAT activity and mitochondrial biogenesis, leading to weight gain in adult rats, a process involving PPAR-γ/UCP1-related thermogenic proteins.

Beneficial effect of Zingiber officinale on olanzapine-induced weight gain and metabolic changes

AIM

The present study aimed to investigate the effect of Zingiber officinale (ZO) extract on weight gain, food intake, locomotor activity, and lipid and glucose metabolism in olanzapine-treated rats.

METHODS

The hydroalcoholic extract of ZO was prepared by macerating the coarse dry powder in 70% v/v ethanol for 7 days, filtered, and concentrated under reduced pressure. Animals were divided into six groups containing six animals in each. Three doses of extract (100, 200, and 400 mg/kg, p.o.) were co-administered with olanzapine 2 mg/kg i.p for 21 days. Bodyweight and food intake were recorded at the interval of three days and locomotor activity once a week. At the end of the study oral glucose tolerance test was performed followed by the estimation of lipid profile.

RESULTS

Co-administration of hydroalcoholic extract of ZO with olanzapine ameliorated olanzapine-induced weight gain and hyperphagia. Similarly, ZO extract also improved pancreatic β-cell function and glucose and lipid metabolism.

CONCLUSIONS

ZO extract ameliorated olanzapine-induced weight gain and hyperphagia by improving pancreatic β-cell functions and lipid metabolism.

Empagliflozin Effectively Attenuates Olanzapine-Induced Body Weight Gain in Female Wistar Rats

Atypical antipsychotic drugs are commonly associated with undesirable side effects including body weight gain (BWG) and metabolic deficits. Many pharmacological interventions have been tested in an attempt to minimize or prevent these side effects. Preliminary evidence suggests that antidiabetic drugs may be effective in attenuating antipsychotic-induced BWG. In the current study, we examined the effect of an antidiabetic drug empagliflozin (EMPA) on BWG induced by anatypical antipsychotic drug olanzapine (Ola) in female and male Wistar rats. Rats were divided into six groups based on the dose they received: group 1 (female control), group 2 (female EMPA, 20 mg/kg; IG), group 3 (female Ola, 4 mg/kg; IP), group 4 (female Ola, 4 mg/kg; IP + EMPA, 20 mg/kg; IG), group 5 (male control), and group 6 (male Ola, 4 mg/kg; IP). Ola induced sustained increase in BWG. The subsequent treatment of Group 3 and 4 with EMPA attenuated the Ola-induced BWG in female Wistar rats. In terms of the gender difference between female and male Wistar rats, the male control group 5 gained more weight throughout the study as compared to the female control group 1. Similarly, the male Ola group 6 gained more weight throughout the study as compared to the female Ola group 3. However, Ola did not cause any weight difference between male rats treated with Ola in comparison with male control group, thus showing a significant gender difference regarding body weight between male and female Wistar rats regardless of Ola administration. In addition, the present findings showed that EMPA effectively attenuates the Ola induced BWG in female Wistar rats. These novel findings should help to better understand the underlying molecular and behavioral mechanisms contributing to the observed increase in body weight after treatment with Ola and other atypical antipsychotic drugs across male and female rats.

Standardizing the Effective Correlated Dosage of Olanzapine and Empagliflozin in Female Wistar Rats

AIM

The primary aim of this study was to standardize the correlated effective dosage of the antidiabetic drug empagliflozin (EMPA) and the antipsychotic drug olanzapine (Ola).

BACKGROUND

Atypical antipsychotics are associated with BWG and metabolic disturbances for which many approaches have been used to minimize these issues, including antidiabetic drugs. The antidiabetic drugs have been quite effective in reversing BWG induced by the administration of antipsychotic drugs in patients who have psychosis, schizophrenia and bipolar disorder.

OBJECTIVE

The objective of this study was to standardize the correlated effective dosage of EMPA and Ola.

METHODS

The study was carried out for 28 days to represent the chronic effect of Ola on female Wistar rats. Rats were divided into three groups based on the dose they received: control (vehicle), Ola-4 and Ola-8 (4 and 8 mg/kg/OD, respectively), and EMPA-10 and EMPA-20 (10 and 20 mg/kg/OD, respectively).

RESULTS

Both doses of Ola produced a significant increase in the percentage of BWG, however, Ola-4 produced a higher BWG. Also, both the doses of EMPA were able to reverse the effect of Ola-induced BWG; however, EMPA-20 produced a higher reversal in BWG and normalized the rat's body weight.

CONCLUSION

We conclude that Ola-4 and EMPA-20 were the most effective dosage for experimental purposes in female Wistar rats. The findings of this study standardized the effective correlated dosage of olanzapine and empagliflozin in female Wistar rats that will help understand the underlying molecular and behavioral mechanisms.

Voluntary physical activity protects against olanzapine-induced hyperglycemia

Olanzapine (OLZ) is used in the treatment of schizophrenia and a growing number of "off-label" conditions. Although effective in reducing psychoses, OLZ causes rapid impairments in glucose and lipid homeostasis. The purpose of this study was to investigate if voluntary physical activity via wheel running (VWR) would protect against the acute metabolic side effects of OLZ. Male C57BL/6J mice remained sedentary or were provided with running wheels overnight, before treatment with OLZ either at the beginning of the light cycle, or 7 or 24 h following the cessation of VWR. Prior VWR protected against OLZ-induced hyperglycemia immediately and 7 h following a bout of overnight wheel running. Protection against, hyperglycemia immediately following VWR was associated with increased insulin tolerance and an attenuated OLZ-induced increase in the serum glucagon:insulin ratio. The protective effect of VWR against OLZ-induced increases in hyperglycemia and glucagon:insulin ratio was maintained in high-fat fed, and AMPK β1-deficient mice, models which display a potentiated OLZ-induced increase in blood glucose. Repeated OLZ treatment did not impair VWR performance and protection against the acute effects of OLZ on blood glucose was present after 1 wk of daily OLZ treatment in mice given access to running wheels. In contrast to the effects on glucose metabolism, VWR, for the most part, did not impact OLZ-induced perturbations in lipolysis, liver triglyceride accumulation, or whole body substrate oxidation. Collectively, our findings demonstrate the efficacy of voluntary physical activity as an approach to protect against OLZ-induced impairments in glucose metabolism.NEW & NOTEWORTHY The antipsychotic medication olanzapine causes rapid and large increases in blood glucose. We demonstrate that a prior bout of voluntary overnight wheel running can protect against this harmful side effect and is likely mediated by reductions in olanzapine-induced increases in the circulating glucagon to insulin ratio. This study highlights the powerful effects of voluntary activity in conditions of treatment with antipsychotic medications.

Role of TRPV1/TRPV3 channels in olanzapine-induced metabolic alteration: Possible involvement in hypothalamic energy-sensing, appetite regulation, inflammation and mesolimbic pathway

Atypical antipsychotics (AAPs) have the tendency of inducing severe metabolic alterations like obesity, diabetes mellitus, insulin resistance, dyslipidemia and cardiovascular complications. These alterations have been attributed to altered hypothalamic appetite regulation, energy sensing, insulin/leptin signaling, inflammatory reactions and active reward anticipation. Line of evidence suggests that transient receptor potential vanilloid type 1 and 3 (TRPV1 and TRPV3) channels are emerging targets in treatment of obesity, diabetes mellitus and could modulate feed intake. The present study was aimed to investigate the putative role TRPV1/TRPV3 in olanzapine-induced metabolic alterations in mice. Female BALB/c mice were treated with olanzapine for six weeks to induce metabolic alterations. Non-selective TRPV1/TRPV3 antagonist (ruthenium red) and selective TRPV1 (capsazepine) and TRPV3 antagonists (2,2-diphenyltetrahydrofuran or DPTHF) were used to investigate the involvement of TRPV1/TRPV3 in chronic olanzapine-induced metabolic alterations. These metabolic alterations were differentially reversed by ruthenium red and capsazepine, while DPTHF didn't show any significant effect. Olanzapine treatment also altered the mRNA expression of hypothalamic appetite-regulating and nutrient-sensing factors, inflammatory genes and TRPV1/TRPV3, which were reversed with ruthenium red and capsazepine treatment. Furthermore, olanzapine treatment also increased expression of TRPV1/TRPV3 in nucleus accumbens (NAc), TRPV3 expression in ventral tegmental area (VTA), which were reversed by the respective antagonists. However, DPTHF treatment showed reduced feed intake in olanzapine treated mice, which might be due to TRPV3 specific antagonism and reduced hedonic feed intake. In conclusion, our results suggested the putative role TRPV1 in hypothalamic dysregulations and TRPV3 in the mesolimbic pathway; both regulate feeding in olanzapine treated mice.

Susceptibility of male wild type mouse strains to antipsychotic-induced weight gain

While both men and women gain weight as a side effect of antipsychotic (AP) treatment, studies in mice have found only female mice are susceptible to weight gain. Therefore, to we set out to identify a strain of male mice that gain significant weight in response to APs which could better model AP-induced weight gain observed in humans. These studies determined that male Balb/c mice developed late onset olanzapine-induced weight gain. Patients often take APs for many years and thus understanding AP-mediated changes in food intake, energy expenditure and body weight regulation is particularly important.

Berberine attenuated olanzapine-induced metabolic alterations in mice: Targeting transient receptor potential vanilloid type 1 and 3 channels

Transient receptor potential vanilloid type 1 (TRPV1) channels are emerging therapeutic targets for metabolic disorders. Berberine, which is a modulator of TRPV1, has proven antiobesity and antidiabetic potentials. The present study was aimed to investigate the protective effects of berberine in olanzapine-induced alterations in hypothalamic appetite control, inflammation and metabolic aberrations in mice targeting TRPV1 channels. Female BALB/c mice (18-23 g) were treated with olanzapine (6 mg/kg, p.o.) for six weeks to induce metabolic alterations, while berberine (100 and 200 mg/kg, p.o.) and metformin (100 mg/kg, p.o) were used as test and standard interventions respectively. Weekly assessment of feed-water intake, body temperature and body weight was done, while locomotion was measured at the end of week 1 and 6. Serum glucose and lipid profile were assessed by biochemical methods, while other serum biomarkers were assessed by ELISA. qPCR was used to quantify the mRNA expression in the hypothalamus. Olanzapine treatment significantly increased the feed intake, weight gain, adiposity index, while reduced body temperature and locomotor activity which were reversed by berberine treatment. Berberine treatment reduced serum ghrelin and leptin levels as well decrease in hypothalamic mRNA expression of orexigenic neuropeptides, inflammatory markers and ghrelin receptor in olanzapine-treated mice. Olanzapine treatment increased expression of TRPV1/TRPV3 in the hypothalamus which was significantly decreased by berberine treatment. Our results suggest that berberine, by TRPV1/TRPV3 modulation, attenuated the olanzapine-induced metabolic alterations in mice. Hence berberine supplementation in psychiatric patients could be a preventive approach to reduce the metabolic adverse effects of antipsychotics.

The Role of Adiponectin in the Pathogenesis of Metabolic Disturbances in Patients With Schizophrenia

Antipsychotic-induced metabolic disturbance is a common adverse event occurring in patients treated with antipsychotic drugs. The mechanisms underlying metabolic dysregulation are complex, involving various neurochemical and hormonal systems, the interaction of genetic and lifestyle risk factors, and the antipsychotic drug prescribed. Recently, there has been increasing interest in the relationship between antipsychotic-induced metabolic disturbances and body weight regulatory hormones such as adiponectin. Adiponectin, an adipocyte-derived protein related to insulin sensitivity, weight gain, and anti-inflammation, has attracted great attention because of its potential role of being a biomarker to predict cardiovascular and metabolic diseases. Previous studies regarding the effects of antipsychotics on blood adiponectin levels have shown controversial results. Several factors might contribute to those inconsistent results, including different antipsychotic drugs, duration of antipsychotic exposure, age, sex, and ethnicity. Here we summarize the existing evidence on the link between blood adiponectin levels and metabolic disturbances related to antipsychotic drugs in patients with schizophrenia. We further discuss the effects of individual antipsychotics, patients' gender, ethnicity, age, and treatment duration on those relationships. We propose that olanzapine and clozapine might have a time-dependent biphasic effect on blood adiponectin levels in patients with schizophrenia.

Samidorphan mitigates olanzapine-induced weight gain and metabolic dysfunction in rats and non-human primates

BACKGROUND

Olanzapine, regarded as one of the most efficacious antipsychotic medications for the treatment of schizophrenia, is associated with a high risk of weight gain and metabolic dysfunction. ALKS 3831, a clinical candidate for treatment of schizophrenia, is a combination of olanzapine and samidorphan, an opioid receptor antagonist. The addition of samidorphan is intended to mitigate weight gain and the metabolic dysregulation associated with the use of olanzapine.

METHODS

Non-clinical studies were conducted to assess the metabolic effects of olanzapine and samidorphan alone and in combination at clinically relevant exposure levels.

RESULTS

Chronic olanzapine administration in male and female rats shifted body composition by increasing adipose mass, which was accompanied by an increase in the rate of weight gain in female rats. Co-administration of samidorphan normalized body composition in both sexes and attenuated weight gain in female rats. In hyperinsulinemic euglycemic clamp experiments conducted prior to measurable changes in weight and/or body composition, olanzapine decreased hepatic insulin sensitivity and glucose uptake in muscle while increasing uptake in adipose tissue. Samidorphan appeared to normalize glucose utilization in both tissues, but did not restore hepatic insulin sensitivity. In subsequent studies, samidorphan normalized olanzapine-induced decreases in whole-body glucose clearance following bolus insulin administration. Results from experiments in female monkeys paralleled the effects in rats.

CONCLUSIONS

Olanzapine administration increased weight gain and adiposity, both of which were attenuated by samidorphan. Furthermore, the combination of olanzapine and samidorphan prevented olanzapine-induced insulin insensitivity. Collectively, these data indicate that samidorphan mitigates several metabolic abnormalities associated with olanzapine in both the presence and the absence of weight gain.

Preclinical and Clinical Sex Differences in Antipsychotic-Induced Metabolic Disturbances: A Narrative Review of Adiposity and Glucose Metabolism

Antipsychotic (AP) medications are associated with an increased risk of developing metabolic side effects including weight gain, type 2 diabetes (T2D), dyslipidemia, and hypertension. In the majority of clinical studies, females on APs are noted to gain more weight, and are more likely to be diagnosed with metabolic syndrome when compared to males. However, the data is less clear when comparing sex disparities associated with other specific AP-induced metabolic risk factors. Accumulating evidence has demonstrated a role for AP-induced adipose tissue accumulation as well as whole body glucose dysregulation in male models that is independent of changes in body weight. The purpose of this narrative review is to explore the susceptibility of males and females to changes in adiposity and glucose metabolism across clinical and preclinical models of AP treatment. It is important that future research examining AP-induced metabolic side effects analyzes outcomes by sex to help clarify risk and identify the mechanisms of adverse event development to improve safe prescribing of medications.

Antihypertensive effects of Korean wild simulated ginseng (Sanyangsam) extracts in spontaneously hypertensive rats

Ginseng possesses a wide spectrum of medicinal effects and has widely been used in traditional medicine for thousands of years. In this study, the antihypertensive effect of Korean wild simulated ginseng in spontaneously hypertensive rats was investigated. Three groups of hypertensive rats-a group without wild simulated ginseng treatment; another group treated with 100 mg of wild simulated ginseng extract/kg of body weight; and the other group treated with 200 mg of wild simulated ginseng extract/kg of body weight were tested over 8 weeks. The two wild simulated ginseng-treated groups showed significantly (p < 0.05) reduced systolic blood pressure at 4 and 6 weeks of wild simulated ginseng treatment. However, the wild simulated ginseng treatment did not adversely affect the food intake, serum electrolytes, osmolality, heart weight, heart rate, and the cross-section of the aorta as well as enzyme activities. The results suggested that Korean wild simulated ginseng is effectively used for reducing high systolic blood pressure in hypertensive patients without causing adverse health effects.

Atypical antipsychotics-induced metabolic syndrome and nonalcoholic fatty liver disease: a critical review

The atypical antipsychotics (AAPs) have been used as first-line drugs in psychiatric practice for a wide range of psychotic disorders, including schizophrenia and bipolar mania. While effectively exerting therapeutic effects on positive and negative symptoms, as well as cognitive impairments in schizophrenia patients, these drugs are less likely to induce extrapyramidal symptoms compared to typical antipsychotics. However, the increasing application of them has raised questions on their tolerability and adverse effects over the endocrine, metabolic, and cardiovascular axes. Specifically, AAPs are associated to different extents, with weight gain, metabolic syndrome (MetS), and nonalcoholic fatty liver disease (NAFLD). This article summarized clinical evidence showing the metabolic side effects of AAPs in patients with schizophrenia, and experimental evidence of AAPs-induced metabolic side effects observed in animals and cell culture studies. In addition, it discussed potential mechanisms involved in the APPs-induced MetS and NAFLD.

Olanzapine - Focus on the Cardiometabolic Side Effects

In this article, we review the recent findings concerning weight gain, diabetes mellitus (DM), hyperlipidemia, cardiovascular side effects in patients receiving olanzapine. It will consider the OLZ is associated with an increase in metabolic syndrome or cardiovascular events, and knowledge of these risks is crucial for further monitoring of patients with OLZ-treatment. Although it is one of the most commonly prescribed and effective AATPs, olanzapine causes the most weight gain and metabolic impairments in humans. As noted with glucose abnormalities and antipsychotics, olanzapine has the greatest propensity for causing proatherogenic hyperlipidemia. The mechanism of dyslipidemia with OLZ is poorly understood, but OLZ has been shown to increase lipogenesis, reduce lipolysis, and enhance the antilipolytic effects of insulin in adipocytes. Olanzapine can induce cardiomyopathy in selected patients.

Taken together, all mentioned data indicate that interventions aimed at the amelioration of obesity and cardiovascular illness need to be as multipronged and complex as the contributing psychosocial, behavioural, and biological factors that make obesity and cardiovascular illness more likely in patients with severe mental illness, including schizophrenia.

The Wnt Signaling Pathway Effector TCF7L2 Mediates Olanzapine-Induced Weight Gain and Insulin Resistance

Olanzapine is a widely used atypical antipsychotic medication for treatment of schizophrenia and is often associated with serious metabolic abnormalities including weight gain and impaired glucose tolerance. These metabolic side effects are severe clinical problems but the underpinning mechanism remains poorly understood. Recently, growing evidence suggests that Wnt signaling pathway has a critical role in the pathogenesis of schizophrenia and molecular cascades of antipsychotics action, of which Wnt signaling pathway key effector TCF7L2 is strongly associated with glucose homeostasis. In this study, we aim to explore the characteristics of metabolic disturbance induced by olanzapine and to elucidate the role of TCF7L2 in this process. C57BL/6 mice were subject to olanzapine (4 mg/kg/day), or olanzapine plus metformin (150 mg/kg/day), or saline, respectively, for 8 weeks. Metabolic indices and TCF7L2 expression levels in liver, skeletal muscle, adipose, and pancreatic tissues were closely monitored. Olanzapine challenge induced remarkably increased body weight, fasting insulin, homeostasis model assessment-insulin resistance index, and TCF7L2 protein expression in liver, skeletal muscle, and adipose tissues. Notably, these effects could be effectively ameliorated by metformin. In addition, we found that olanzapine-induced body weight gain and insulin resistance actively influence the expression of TCF7L2 in liver and skeletal muscle, and elevated level of insulin determines the increased expression of TCF7L2 in adipose tissue. Our results demonstrate that TCF7L2 participates in olanzapine-induced metabolic disturbance, which presents a novel mechanism for olanzapine-induced metabolic disturbance and a potential therapeutic target to prevent the associated metabolic side effects.

Antipsychotic Drugs: From Receptor-binding Profiles to Metabolic Side Effects

BACKGROUND

Antipsychotic-induced metabolic side effects are major concerns in psychopharmacology and clinical psychiatry. Their pathogenetic mechanisms are still not elucidated.

METHODS

Herein, we review the impact of neurotransmitters on metabolic regulation, providing insights into antipsychotic-induced metabolic side effects.

RESULTS

Antipsychotic drugs seem to interfere with feeding behaviors and energy balance, processes that control metabolic regulation. Reward and energy balance centers in central nervous system constitute the central level of metabolic regulation. The peripheral level consists of skeletal muscles, the liver, the pancreas, the adipose tissue and neuroendocrine connections. Neurotransmitter receptors have crucial roles in metabolic regulation and they are also targets of antipsychotic drugs. Interaction of antipsychotics with neurotransmitters could have both protective and harmful effects on metabolism.

CONCLUSION

Emerging evidence suggests that antipsychotics have different liabilities to induce obesity, diabetes and dyslipidemia. However this diversity cannot be explained merely by drugs'pharmacodynamic profiles, highlighting the need for further research.

Neural circuits of eating behaviour: Opportunities for therapeutic development

Understanding of the neural and physiological substrates of hunger and satiety has increased rapidly over the last three decades, and pharmacological targets have already been identified for the treatment of obesity that has moved from pre-clinical screening to therapies approved by regulatory authorities. Initially, this review describes the way in which physiological signals of energy availability interact with hedonic and rewarding properties of food to modulate the neural circuitry that supports eating behaviour. This is followed by a brief account of current and promising targets for drug development and a review of the wide range of preclinical paradigms that model important influences on human eating behaviour, and can be used to guide early stages of the drug development process.

Roman high and low avoidance rats differ in their response to chronic olanzapine treatment at the level of body weight regulation, glucose homeostasis, and cortico-mesolimbic gene expression

Olanzapine, an antipsychotic agent mainly used for treating schizophrenia, is frequently associated with body weight gain and diabetes mellitus. Nonetheless, studies have shown that not every individual is equally susceptible to olanzapine's weight-gaining effect. Therefore, Roman high and low avoidance rat strains were examined on their responsiveness to olanzapine treatment. The Roman high avoidance rat shares many behavioral and physiological characteristics with human schizophrenia, such as increased central dopaminergic sensitivity, whereas the Roman low avoidance rat has been shown to be prone to diet-induced obesity and insulin resistance. The data revealed that only the Roman high avoidance rats are susceptible to olanzapine-induced weight gain and attenuated glucose tolerance. Here it is suggested that the specific olanzapine-induced weight gain in Roman high avoidance rats could be related to augmented dopaminergic sensitivity at baseline through increased expression of prefrontal cortex dopamine receptor D1 mRNA and nucleus accumbens dopamine receptor D2 mRNA expression. Regression analyses revealed that olanzapine-induced weight gain in the Roman high avoidance rat is above all related to increased prolactin levels, whereas changes in glucose homeostasis is best explained by differences in central dopaminergic receptor expressions between strains and treatment. Our data indicates that individual differences in dopaminergic receptor expression in the cortico-mesolimbic system are related to susceptibility to olanzapine-induced weight gain.

The atypical antipsychotic olanzapine causes weight gain by targeting serotonin receptor 2C

Atypical antipsychotics such as olanzapine often induce excessive weight gain and type 2 diabetes. However, the mechanisms underlying these drug-induced metabolic perturbations remain poorly understood. Here, we used an experimental model that reproduces olanzapine-induced hyperphagia and obesity in female C57BL/6 mice. We found that olanzapine treatment acutely increased food intake, impaired glucose tolerance, and altered physical activity and energy expenditure in mice. Furthermore, olanzapine-induced hyperphagia and weight gain were blunted in mice lacking the serotonin 2C receptor (HTR2C). Finally, we showed that treatment with the HTR2C-specific agonist lorcaserin suppressed olanzapine-induced hyperphagia and weight gain. Lorcaserin treatment also improved glucose tolerance in olanzapine-fed mice. Collectively, our studies suggest that olanzapine exerts some of its untoward metabolic effects via antagonism of HTR2C.

Antenatal antipsychotic exposure induces multigenerational and gender-specific programming of adiposity and glucose tolerance in adult mouse offspring

Second-generation antipsychotics (SGAs) are well known for their metabolic side effects in humans, including obesity and diabetes. These compounds are maintained during pregnancy to prevent the relapse of psychoses, but they readily diffuse across the placenta to the fetus, as documented with the widely-prescribed drug olanzapine (OLZ). However, observational studies have provided conflicting results on the potential impact of SGAs on fetal growth and body weight, and their effects on metabolic regulation in the offspring. For this reason, our study has tested whether antenatal exposure of CD1 mice to OLZ influenced metabolic outcomes in the offspring of the first (F1) and second (F2) generations. In F1 mice, OLZ antenatal treatment caused a decrease in neonatal body weight in both genders, an effect that persisted throughout life only in male animals. Interestingly, F1 female mice also displayed altered glucose homoeostasis. F2 mice, generated by mating normal males with F1 female mice exposed to OLZ during antenatal life, exhibited higher neonatal body weights which persisted only in F2 female animals. This was associated with expansion of fat mass and a concordant pattern of adipose tissue gene expression. Moreover, male and female F2 mice were glucose-intolerant. Thus, our study has demonstrated that antenatal OLZ exposure induces multigenerational and gender-specific programming of glucose tolerance in the offspring mice as adults, and points to the need for careful monitoring of children exposed to SGAs during pregnancy.

Atypical antipsychotics and effects on feeding: from mice to men

RATIONALE

So-called atypical antipsychotics (AAPs) are associated with varying levels of weight gain and associated metabolic disturbances, which in patients with serious mental illness (SMI) have been linked to non-compliance and poor functional outcomes. Mechanisms underlying AAP-induced metabolic abnormalities are only partially understood. Antipsychotic-induced weight gain may occur as a result of increases in food intake and/or changes in feeding.

OBJECTIVE

In this review, we examine the available human and preclinical literature addressing AAP-related changes in feeding behavior, to determine whether changes in appetite and perturbations in regulation of food intake could be contributing factors to antipsychotic-induced weight gain.

RESULTS

In general, human studies point to disruption by AAPs of feeding behaviors and food consumption. In rodents, increases in cumulative food intake are mainly observed in females; however, changes in feeding microstructure or motivational aspects of food intake appear to occur independent of sex.

CONCLUSIONS

The findings from this review indicate that the varying levels of AAP-related weight gain reflect changes in both appetite and feeding behaviors, which differ by type of AAP. However, inconsistencies exist among the studies (both human and rodent) that may reflect considerable differences in study design and methodology. Future studies examining underlying mechanisms of antipsychotic-induced weight gain are recommended in order to develop strategies addressing the serious metabolic side effect of AAPs.

The utility of behavioral economics in expanding the free-feed model of obesity

Animal models of obesity are numerous and diverse in terms of identifying specific neural and peripheral mechanisms related to obesity; however, they are limited when it comes to behavior. The standard behavioral measure of food intake in most animal models occurs in a free-feeding environment. While easy and cost-effective for the researcher, the free-feeding environment omits some of the most important features of obesity-related food consumption-namely, properties of food availability, such as effort and delay to obtaining food. Behavior economics expands behavioral measures of obesity animal models by identifying such behavioral mechanisms. First, economic demand analysis allows researchers to understand the role of effort in food procurement, and how physiological and neural mechanisms are related. Second, studies on delay discounting contribute to a growing literature that shows that sensitivity to delayed food- and food-related outcomes is likely a fundamental process of obesity. Together, these data expand the animal model in a manner that better characterizes how environmental factors influence food consumption.

Antipsychotic-induced metabolic effects in the female rat: Direct comparison between long-acting injections of risperidone and olanzapine

Several antipsychotics have well-known adverse metabolic effects. Studies uncovering molecular mechanisms of such drugs in patients are challenging due to high dropout rates, previous use of antipsychotics and restricted availability of biological samples. Rat experiments, where previously unexposed animals are treated with antipsychotics, allow for direct comparison of different drugs, but have been hampered by the short half-life of antipsychotics in rodents. The use of long-acting formulations of antipsychotics could significantly increase the value of rodent models in the molecular characterization of therapeutic and adverse effects of these agents. However, as long-acting formulations have rarely been used in rodents, there is a need to characterize the basic metabolic phenotype of different antipsychotics. Using long-acting olanzapine injections as a positive control, the metabolic effects of intramuscular long-acting risperidone in female rats were investigated for the first time. Like olanzapine, risperidone induced rapid, significant hyperphagia and weight gain, with concomitant increase in several plasma lipid species. Both drugs also induced weight-independent upregulation of several genes encoding enzymes involved in lipogenesis, but this activation was not confirmed at the protein level. Our findings shed light on the role of drug administration, drug dose and nutritional status in the development of rodent models for adverse metabolic effects of antipsychotic agents.

A comparison of the nutrient intake of a community-dwelling first-episode psychosis cohort, aged 19-64 years, with data from the UK population

Psychosis increases the risk of CVD, obesity and type 2 diabetes and reduces life expectancy. There are limited data comparing the dietary habits of community-dwelling first-episode psychosis sufferers - with autonomy over diet - and the general population. The data represent the retrospective evaluation of nutritional data collected between 2007 and 2013 from 143 individuals from the UK population receiving treatment for first-episode psychosis. Differences in mean nutrient intakes between the study cohort and the national sample were tested for statistical significance using independent t tests, incorporating Satterthwaite's correction where required. Mean total energy intake was lower for males (P = 0·049) and higher for females (P = 0·016) in the cohort than in the corresponding subgroups of the national sample. Females in the study cohort consumed 12·9 (95 % CI 4·3, 21·5) g more total fat per d, whilst males consumed 7·7 (95 % CI 0·5, 14·9) g less protein per d than the national sample. Males in the study also showed significantly lower mean intakes than nationally of folate, Fe, Se, vitamin D and Zn, but not vitamin C. The proportion of individuals not meeting the lower reference nutrient intakes, particularly for Se (males 54·0 % and females 57·1 %) and for Fe amongst females (29·6 %), is cause for concern regarding potentially severe deficiencies. Further exploration of dietary habits within first-episode psychosis is warranted to assess whether individuals make beneficial dietary changes for their physical and mental health and wellbeing following dietary change intervention. It would also be pertinent to assess any correlation between diet and mental health symptomology.

Olanzapine depot exposure in male rats: Dose-dependent lipogenic effects without concomitant weight gain

Treatment with second-generation antipsychotic agents such as olanzapine frequently results in metabolic adverse effects, e.g. hyperphagia, weight gain and dyslipidaemia in patients of both genders. The molecular mechanisms underlying metabolic adverse effects are still largely unknown, and studies in rodents represent an important approach in their exploration. However, the validity of the rodent model is hampered by the fact that antipsychotics induce weight gain in female, but not male, rats. When administered orally, the short half-life of olanzapine in rats prevents stable plasma concentrations of the drug. We recently showed that a single intramuscular injection of long-acting olanzapine formulation yields clinically relevant plasma concentrations accompanied by several dysmetabolic features in the female rat. In the current study, we show that depot injections of 100-250 mg/kg olanzapine yielded clinically relevant plasma olanzapine concentrations also in male rats. In spite of transient hyperphagia, however, olanzapine resulted in weight loss rather than weight gain. The resultant negative feed efficiency was accompanied by a slight elevation of thermogenesis markers in brown adipose tissue for the highest olanzapine dose, but the olanzapine-related reduction in weight gain remains to be explained. In spite of the absence of weight gain, an olanzapine dose of 200mg/kg or above induced significantly elevated plasma cholesterol levels and pronounced activation of lipogenic gene expression in the liver. These results confirm that olanzapine stimulates lipogenic effects, independent of weight gain, and raise the possibility that endocrine factors may influence gender specificity of metabolic effects of antipsychotics in the rat.

Preliminary Examination of Olanzapine and Diet Interactions On Metabolism in a Female Macaque

Clinical data suggest that atypical antipsychotics such as olanzapine (OLZ) induce significant metabolic changes that are serious side effects of their primary use. Since controlled human studies are problematic and rodent data may be poorly translatable, we have initiated development of a macaque model of OLZ-induced metabolic disease. In this preliminary feasibility study, we examined some metabolic effects of OLZ in a female macaque in the context of a standard low-calorie/fat monkey chow diet followed by a high-fat/sugar Western-style diet (WSD). A female Japanese macaque was administered OLZ (1.25 mg/day) for 6 months, with dietary changes at 2-month intervals as follows: OLZ+Restricted chow, OLZ+Unrestricted chow, OLZ+WSD, and placebo+WSD. Weight was assessed weekly. Glucose tolerance tests (GTT) and Dexascans were performed at baseline and every 2 months. Omental (OM) and subcutaneous (SQ) adipose tissue biopsies were obtained at baseline, after OLZ+Unrestricted chow and after OLZ+WSD to evaluate adipocyte size, lipolysis and insulin-stimulated free fatty acid uptake (FFA). A separate trial was conducted on 2 monkeys with 5 days of OLZ- or no-treatment followed by RT-PCR on rostral and medial basal hypothalamus. Weight increased on OLZ+Restricted chow and stabilized on OLZ+Unrestricted chow. OLZ+WSD did not significantly change the weight plateau. Weight declined upon withdrawal of OLZ with continued WSD. Body fat increased from 14% at baseline to 22%, 30%, 28% and 19% at 2, 4, 6 and 8 mo, respectively, indicating that body fat was elevated on OLZ regardless of diet and declined upon OLZ removal. Glucose tolerance and the insulin response during GTT were normal with OLZ+Restricted chow or OLZ+Unrestricted chow. Addition of WSD with OLZ impaired glucose clearance during GTT. Insulin remained in the normal range, but first phase insulin secretion was reduced. After removal of OLZ, but continued WSD, glucose clearance returned to normal, but this was associated with hyperinsulinemia. Adipocyte diameter was increased in OM and SQ fat by OLZ+chow and OLZ+WSD to a similar extent. (p<0.01, 2-way ANOVA). In OM, isoproterenol-stimulated lipolysis occurred at baseline. In both depots, isoproterenol-stimulated lipolysis occurred with OLZ+chow, but it was significantly blunted by addition of WSD (ANOVA p<0.0001; posthoc p<0.05). Insulin increased FFA uptake at baseline. OLZ +chow or OLZ+WSD increased basal FFA uptake and insulin-induced FFA uptake was blunted in both depots (posthoc p<0.05). There was a marked decrease in POMC gene expression, and increased AgRP and NPY expression in the hypothalamus. There was also a clear increase in serotonin (5HT) 2C, melanocortin (MCR4), and Leptin (LepR) receptor gene expression. These data support the hypotheses that OLZ acts on peripheral tissues as well as in the CNS; that changes in hypothalamic gene expression occur very rapidly and precede increased fat accumulation; that adipose tissue exhibits insulin resistance prior to alterations in GTT; that addition of WSD to OLZ precipitates hyperglycemia without an obvious insulin response; and that removal of OLZ and continued WSD resulted in normalized glucose clearance and elevated insulin. These data suggest complex and early responses to OLZ that may be exacerbated by WSD.

Effects of olanzapine on the elevation of macrophage infiltration and pro-inflammatory cytokine expression in female rats

The metabolic side-effects of olanzapine have undermined drug compliance and increased concern for this otherwise-effective treatment for schizophrenia. As obesity and type 2 diabetes are associated with low-grade inflammation, and olanzapine-induced weight gain has three typical stages, the current study investigated the inflammatory effects of olanzapine in three treatment stages. Female Sprague-Dawley rats were treated orally with olanzapine (1 mg/kg three times daily) or vehicle for one week, two weeks, and five weeks. Olanzapine significantly increased body weight and white visceral fat deposition in all three treatment stages compared to control. Olanzapine enhanced average adipocyte size and level of macrophage infiltration in white adipose tissue (WAT) compared to control, with levels of macrophage infiltration increased over time. There was a high correlation between adipocyte size and macrophage infiltration rate. Olanzapine also caused increased macrophage infiltration in brown adipose tissue (BAT), but not liver. Additionally, pro-inflammatory cytokines tumor necrosis factor α (TNFα), interleukin (IL)-1β, and IL-6 were upregulated by olanzapine in the hypothalamus, WAT, and BAT compared to control, but not the liver. Finally, plasma triglycerides were elevated by olanzapine compared to control, but not total cholesterol, high density lipoprotein (HDL) or low density lipoprotein (LDL). These findings indicate that olanzapine-induced inflammation and adiposity are closely related, and that peripheral low-grade inflammation develops during olanzapine treatment.

Molecular pathophysiology of metabolic effects of antipsychotic medications

Antipsychotic medications are associated with major metabolic changes that contribute to medical morbidity and a significantly shortened life span. The mechanisms for these changes provide us with a broader understanding of central nervous and peripheral organ-mediated metabolic regulation. This paper reviews an extensive literature regarding putative mechanisms for effects of antipsychotic medications on weight regulation and glucose homeostasis as well as potential inherent metabolic risks of schizophrenia itself. We present a model suggesting that peripheral antipsychotic targets play a critical role in drug-induced weight gain and diabetes. We propose that a better understanding of these mechanisms will be crucial to developing improved treatments for serious mental illnesses as well as providing potentially novel therapeutic targets of metabolic disorders including diabetes.

The aetiology of obesity beyond eating more and exercising less

Although recent increases in availability of energy dense, processed foods and reductions in institutionally driven physical activity have created an environment that is permissible for obesity to occur, several other factors may contribute to the development of obesity in this context. We review evidence for eleven such factors: endocrine disruptors, intrauterine effects, epigenetics, maternal age, differential fecundity and assortative mating by body mass index, microorganisms, reduction in variability of ambient temperatures, smoking cessation, sleep debt, and pharmaceutical iatrogenesis. Evidence for the role of endocrine disruptors, microorganisms, ambient temperatures, sleep and reproductive factors is accumulating, but additional research is needed to confirm the causative role of these factors in human obesity. However, the role of certain pharmaceuticals and smoking cessation in development of human obesity is clear. Practice points for consideration and future research needed are highlighted for each factor.

Modelling olanzapine-induced weight gain in rats

The second-generation antipsychotic drug olanzapine has become a widely prescribed drug in the treatment of schizophrenia and bipolar disorder. Unfortunately, its therapeutic benefits are partly outweighed by significant weight gain and other metabolic side effects, which increase the risk for diabetes and cardiovascular disease. Because olanzapine remains superior to other antipsychotic drugs that show less weight gain liability, insight into the mechanisms responsible for olanzapine-induced weight gain is crucial if it is to be effectively addressed. Over the past few decades, several groups have investigated the effects of olanzapine on energy balance using rat models. Unfortunately, results from different studies have not always been consistent and it remains to be determined which paradigms should be used in order to model olanzapine-induced weight gain most accurately. This review summarizes the effects of olanzapine on energy balance observed in different rat models and discusses some of the factors that appear to contribute to the inconsistencies in observed effects. In addition it compares the effects reported in rats with clinical findings to determine the predictive validity of different paradigms.

Olanzapine depot formulation in rat: a step forward in modelling antipsychotic-induced metabolic adverse effects

Rats are used as animal models in the study of antipsychotic-induced metabolic adverse effects, with oral drug administration yielding hyperphagia, weight gain and, in some cases, lipogenic effects. However, the rapid half-life of these drugs in rats, in combination with development of drug tolerance after a few weeks of treatment, has limited the validity of the model. In order to prevent fluctuating drug serum concentrations seen with daily repeated administrations, we injected female rats with a single intramuscular dose of long-acting olanzapine formulation. The olanzapine depot injection yielded plasma olanzapine concentrations in the range of those achieved in patients, and induced changes in metabolic parameters similar to those previously observed with oral administration, including increased food intake, weight gain and elevated plasma triglycerides. Moreover, the sensitivity to olanzapine was maintained beyond the 2-3 wk of weight gain observed with oral administration. In a separate olanzapine depot experiment, we aimed to clarify the role of hypothalamic AMP-activated protein kinase (AMPK) in olanzapine-induced weight gain, which has been subject to debate. Adenovirus-mediated inhibition of AMPK was performed in the arcuate (ARC) or the ventromedial hypothalamic (VMH) nuclei in female rats, with subsequent injection of olanzapine depot solution. Inhibition of AMPK in the ARC, but not in the VMH, attenuated the weight-inducing effect of olanzapine, suggesting an important role for ARC-specific AMPK activation in mediating the orexigenic potential of olanzapine. Taken together, olanzapine depot formulation provides an improved mode of drug administration, preventing fluctuating plasma concentrations, reducing handling stress and opening up possibilities to perform complex mechanistic studies.

In vivo pharmacological evaluations of novel olanzapine analogues in rats: a potential new avenue for the treatment of schizophrenia

Olanzapine (Olz) is one of the most effective antipsychotic drugs commonly used for treating schizophrenia. Unfortunately, Olz administration is associated with severe weight gain and metabolic disturbances. Both patients and clinicians are highly interested in the development of new antipsychotics which are as effective as atypical antipsychotics but which have a lower propensity to induce metabolic side effects. In the present study, we examined two new derivatives of Olz; OlzEt (2-ethyl-4-(4'-methylpiperazin-1'-yl)-10Hbenzo[b]thieno[2,3-e][1,4]diazepine), and OlzHomo (2-ethyl-4-(4'-methyl-1',4'-diazepan-1'-yl)-10H-benzo[b]thieno[2,3-e] [1,4]diazepine), for their tendency to induce weight gain in rats. Weight gain and metabolic changes were measured in female Sprague Dawley rats. Animals were treated orally with Olz, OlzEt, OlzHomo (3 or 6 mg/kg/day), or vehicle (n = 8), three times daily at eight-hour intervals for 5 weeks. Furthermore, a phencyclidine (PCP)-treated rat model was used to examine the prevention of PCP-induced hyperlocomotor activity relevant for schizophrenia therapy. Male Sprague Dawley rats were pre-treated with a single dose (3 mg/kg/day) of Olz, OlzEt, OlzHomo, or vehicle (n = 12), for 2 weeks. Locomotor activity was recorded following a subcutaneous injection with either saline or PCP (10 mg/kg). Olz was found to induce weight gain, hyperphagia, visceral fat accumulation, and metabolic changes associated with reduced histamatergic H1 receptor density in the hypothalamus of treated rats. In contrast, OlzEt and OlzHomo presented promising antipsychotic effects, which did not induce weight gain or fat deposition in the treated animals. Behavioural analysis showed OlzEt to attenuate PCP-induced hyperactivity to a level similar to that of Olz; however, OlzHomo showed a lower propensity to inhibit these stereotyped behaviours. Our data suggest that the therapeutic effectiveness of OlzHomo may be delivered at a higher dose than that of Olz and OlzEt. Overall, OlzEt and OlzHomo may offer a better pharmacological profile than Olz for treating patients with schizophrenia. Clinical trials are needed to test this hypothesis.

Differential effects of 3 classes of antidiabetic drugs on olanzapine-induced glucose dysregulation and insulin resistance in female rats

BACKGROUND

The second-generation antipsychotic drug olanzapine is an effective pharmacological treatment for psychosis. However, use of the drug is commonly associated with a range of metabolic side effects, including glucose intolerance and insulin resistance. These symptoms have been accurately modelled in rodents.

METHODS

We compared the effects of 3 distinct classes of antidiabetic drugs, metformin (100 and 500 mg/kg, oral), rosiglitazone (6 and 30 mg/kg, oral) and glyburide (2 and 10 mg/kg, oral), on olanzapineinduced metabolic dysregulation. After acutely treating female rats with lower (7.5 mg/kg) or higher (15 mg/kg) doses of olanzapine, we assessed glucose intolerance using the glucose tolerance test and measured insulin resistance using the homeostatic model assessment of insulin resistance equation.

RESULTS

Both doses of olanzapine caused pronounced glucose dysregulation and insulin resistance, which were significantly reduced by treatment with metformin and rosiglitazone; however, glucose tolerance did not fully return to control levels. In contrast, glyburide failed to reverse the glucose intolerance caused by olanzapine despite increasing insulin levels.

LIMITATIONS

We evaluated a single antipsychotic drug, and it is unknown whether other antipsychotic drugs are similarly affected by antidiabetic treatments.

CONCLUSION

The present study indicates that oral hypoglycemic drugs that influence hepatic glucose metabolism, such as metformin and rosiglitazone, are more effective in regulating olanzapine-induced glucose dysregulation than drugs primarily affecting insulin release, such as glyburide. The current model may be used to better understand the biological basis of glucose dysregulation caused by olanzapine and how it can be reversed.

Effects of naltrexone on food intake and body weight gain in olanzapine-treated rats

Blockade of opioidergic neurotransmission contributes to reduction in body weight. However, how such blockade affects body weight gain (BWG) attributed to second generation antipsychotic agents (SGAs) has not yet been established. Here we examined the effects of an opioid receptor antagonist, naltrexone (NTX), on food intake and BWG associated with an SGA, olanzapine (OL). Four groups of Wistar Han IGS rats were treated for 28 days with either OL (2 mg/kg twice daily, intraperitoneal (IP)), a combination of OL (2 mg/kg twice daily, IP) + extended-release NTX (50 mg/kg, one-time, intramuscular (IM)), extended-release NTX (50 mg/kg, one-time, IM) or vehicle and their food intake and body weight were measured daily for the first nine days and every other day thereafter. Food intake and BWG that were increased by OL were decreased by the added NTX while NTX alone had no significant effects on food intake or on BWG. Plasma leptin concentrations were significantly elevated in the three groups receiving pharmacological agents, but did not differ among each other, suggesting that changes in leptin secretion and/or clearance alone would not explain the food intake and the body weight findings. Our results extend prior reports on anorexigenic effects of opioid antagonists by demonstrating that such effects may generalize to food intake increases and BWG arising in the context of OL pharmacotherapy.

Omega-3 fatty acid deficiency augments risperidone-induced hepatic steatosis in rats: positive association with stearoyl-CoA desaturase

Psychiatric patients frequently exhibit long-chain n-3 (LCn-3) fatty acid deficits and elevated triglyceride (TAG) production following chronic exposure to second generation antipsychotics (SGAs). Emerging evidence suggests that SGAs and LCn-3 fatty acids have opposing effects on stearoyl-CoA desaturase-1 (SCD1), which plays a pivotal role in TAG biosynthesis. Here we evaluated whether low LCn-3 fatty acid status would augment elevations in rat liver and plasma TAG concentrations following chronic treatment with the SGA risperidone (RSP), and evaluated relationships with hepatic SCD1 expression and activity indices. In rats maintained on the n-3 fatty acid-fortified (control) diet, chronic RSP treatment significantly increased liver SCD1 mRNA and activity indices (18:1/18:0 and 16:1/16:0 ratios), and significantly increased liver, but not plasma, TAG concentrations. Rats maintained on the n-3 deficient diet exhibited significantly lower liver and erythrocyte LCn-3 fatty acid levels, and associated elevations in LCn-6/LCn-3 ratio. In n-3 deficient rats, RSP-induced elevations in liver SCD1 mRNA and activity indices (18:1/18:0 and 16:1/16:0 ratios) and liver and plasma TAG concentrations were significantly greater than those observed in RSP-treated controls. Plasma glucose levels were not altered by diet or RSP, and body weight was lower in RSP- and VEH-treated n-3 deficient rats. These preclinical data support the hypothesis that low n-3 fatty acid status exacerbates RSP-induced hepatic steatosis by augmenting SCD1 expression and activity.

The effect of ziprasidone on body weight and energy expenditure in female rats

Ziprasidone, a novel antipsychotic agent with a unique receptor-binding profile, has been reported to have lower propensity for weight gain compared with other atypical antipsychotics. Here, we examined the effects of ziprasidone on resting energy expenditure, physical activity, thermogenesis, food intake, and weight gain in female Sprague-Dawley rats. Ziprasidone (20 mg/kg) or vehicle was administered once daily for 7 weeks; and body weight, food intake, resting energy expenditure, locomotor activity, colonic temperature on cold exposure, and abdominal fat were measured. Compared with control animals, ziprasidone-treated rats gained significantly less weight (P = .031), had a lower level of physical activity (P = .016), showed a higher resting energy expenditure (P < .001), and displayed a greater capacity for thermogenesis when subjected to cold (P < .001). In addition, ziprasidone-treated rats had a lower level of abdominal fat than did controls, although the difference was not significant. Ziprasidone had no effect on food intake. Our results indicate that, in female Sprague-Dawley rats, a 7-week treatment regimen of ziprasidone induces a significant decrease in weight gain by increasing resting energy expenditure without decreasing food intake and even with a lower level of physical activity. Further studies are needed to elucidate the precise mechanism of lower propensity of weight gain of ziprasidone.

Olanzapine, but not aripiprazole, weight-independently elevates serum triglycerides and activates lipogenic gene expression in female rats

Metabolic adverse effects such as weight gain and dyslipidaemia represent a major concern in treatment with several antipsychotic drugs, including olanzapine. It remains unclear whether such metabolic side-effects fully depend on appetite-stimulating actions, or whether some dysmetabolic features induced by antipsychotics may arise through direct perturbation of metabolic pathways in relevant peripheral tissues. Recent clinical and preclinical studies indicate that dyslipidaemia could occur independently of weight gain. Using a rat model, we showed that subchronic treatment with olanzapine induces weight gain and increases adipose tissue mass in rats with free access to food. This effect was also observed for aripiprazole, considered metabolically neutral in the clinical setting. In pair-fed rats with limited food access, neither olanzapine nor aripiprazole induced weight gain. Interestingly, olanzapine, but not aripiprazole, induced weight-independent elevation of serum triglycerides, accompanied by up-regulation of several genes involved in lipid biosynthesis, both in liver and in adipose tissues. Our findings support the existence of tissue-specific, weight-independent direct effects of olanzapine on lipid metabolism.

Atypical antipsychotics rapidly and inappropriately switch peripheral fuel utilization to lipids, impairing metabolic flexibility in rodents

Patients taking atypical antipsychotics are frequented by serious metabolic (eg, hyperglycemia, obesity, and diabetes) and cardiac effects. Surprisingly, chronic treatment also appears to lower free fatty acids (FFAs). This finding is paradoxical because insulin resistance is typically associated with elevated not lower FFAs. How atypical antipsychotics bring about these converse changes in plasma glucose and FFAs is unknown. Chronic treatment with olanzapine, a prototypical, side effect prone atypical antipsychotic, lowered FFA in Sprague-Dawley rats. Olanzapine also lowered plasma FFA acutely, concomitantly impairing in vivo lipolysis and robustly elevating whole-body lipid oxidation. Increased lipid oxidation was evident from accelerated losses of triglycerides after food deprivation or lipid challenge, elevated FFA uptake into most peripheral tissues (∼2-fold) except heart, rises in long-chain 3-hydroxylated acyl-carnitines observed in diabetes, and rapid suppression of the respiratory exchange ratio (RER) during the dark cycle. Normal rises in RER following refeeding, a sign of metabolic flexibility, were severely blunted by olanzapine. Increased lipid oxidation in muscle could be explained by ∼50% lower concentrations of the negative cytoplasmic regulator of carnitine palmitoyltransferase I, malonyl-CoA. This was associated with loss of anapleurotic metabolites and citric acid cycle precursors of malonyl-CoA synthesis rather than adenosine monophosphate-activated kinase activation or direct ACC1/2 inhibition. The ability of antipsychotics to lower dark cycle RER in mice corresponded to their propensities to cause metabolic side effects. Our studies indicate that lipocentric mechanisms or altered intermediary metabolism could underlie the FFA lowering and hyperglycemia (Randle cycle) as well as some of the other side effects of atypical antipsychotics, thereby suggesting strategies for alleviating them.

Differential effects of olanzapine and risperidone on plasma adiponectin levels over time: results from a 3-month prospective open-label study

Second-generation antipsychotics (SGA), especially clozapine and olanzapine, are associated with an increased metabolic risk. Recent research showed that plasma adiponectin levels, an adipocyte-derived hormone that increases insulin sensitivity, vary in the same way in schizophrenic patients as in the general population according to gender, adiposity and metabolic syndrome (MetS). The aim of the present study was to investigate whether different SGAs differentially affect plasma adiponectin levels independent of body mass index (BMI) and MetS status. 113 patients with schizophrenia (65.5% males, 32.3years old) who were free of antipsychotic medication were enrolled in this open-label prospective single-center study and received either risperidone (n=54) or olanzapine (n=59). They were followed prospectively for 12weeks. Average daily dose was 4.4mg/day for risperidone and 17.4mg/day for olanzapine. Plasma adiponectin levels as well as fasting metabolic parameters were measured at baseline, 6weeks and 12weeks. The two groups had similar baseline demographic and metabolic characteristics. A significant increase in body weight was observed over time. This increase was significantly larger in the olanzapine group than in the risperidone group (+7.0kg versus +3.1kg, p<0.0002). Changes in fasting glucose and insulin levels and in HOMA-IR, an index of insulin resistance, were not significantly different in both treatment groups. MetS prevalence increased significantly more in the olanzapine group as compared to the risperidone groups where the prevalence did not change over time. We observed a significant (p=0.0015) treatment by time interaction showing an adiponectin increase in the risperidone-treated patients (from 10,154 to 11,124ng/ml) whereas adiponectin levels decreased in olanzapine treated patients (from 11,280 to 8988ng/ml). This effect was independent of BMI and the presence/absence of MetS. The differential effect of antipsychotic treatment (risperidone versus olanzapine) on plasma adiponectin levels over time, independent of changes in waist circumference and antipsychotic dosing, suggests a specific effect on adipose tissues, similar to what has been observed in animal models. The observed olanzapine-associated reduction in plasma adiponectin levels may at least partially contribute to the increased metabolic risk of olanzapine compared to risperidone.

Metabolic consequences of antipsychotic therapy: preclinical and clinical perspectives on diabetes, diabetic ketoacidosis, and obesity

Antipsychotic drugs, particularly second-generation antipsychotics (SGAs), have reduced the burden to society of schizophrenia, but many still produce excessive weight gain. A significant number of SGAs also act directly to impair glycemic control causing insulin resistance, impaired glucose tolerance and type 2 diabetes, and also rarely diabetic ketoacidosis (DKA). Schizophrenia itself is almost certainly causal in many endocrine and metabolic disturbances, making this population especially vulnerable to the adverse metabolic consequences of treatment with SGAs. Hence, there is an urgent need for a new generation of antipsychotic drugs that provide efficacy equal to the best of the SGAs without their liability to cause weight gain or type 2 diabetes. In the absence of such safe and effective alternatives to the SGAs, there is a substantial clinical need for the introduction of new antipsychotics without adverse metabolic effects and new antiobesity drugs to combat these metabolic side effects. We discuss the adverse metabolic consequences of schizophrenia, its exacerbation by a lack of social care, and the additional burden placed on patients by their medication. A critical evaluation of the animal models of antipsychotic-induced metabolic disturbances is provided with observations on their strengths and limitations. Finally, we discuss novel antipsychotic drugs with a lower propensity to increase metabolic risk and adjunctive medications to mitigate the adverse metabolic actions of the current generation of antipsychotics.

Olanzapine effects on body composition, food preference, glucose metabolism and insulin sensitivity in the rat

The atypical antipsychotic drug olanzapine induces weight gain and defects in glucose metabolism in patients. Using a rat model we investigated the effects of acute and long term olanzapine treatment on weight gain, food preference and glucose metabolism. Olanzapine treated rats fed a chow diet grew more slowly than vehicle controls but olanzapine treated animals fed a high fat/sugar diet grew faster than control animals on the same diet. These changes in weight were paralleled by changes in fat mass. Olanzapine also induced a strong preference for a high fat/high sugar diet. Acute exposure to olanzapine rapidly induced severe impairments of glucose tolerance and increased insulin secretion but did not impair insulin tolerance. These results indicate the defect in glucose metabolism induced by acute olanzapine treatment was most likely due to increased hepatic glucose output associated with a reduction in active GLP-1 levels and correspondingly high glucagon levels.

Atypical antipsychotics and the neural regulation of food intake and peripheral metabolism

The atypical antipsychotics (AAPs) are associated with weight gain and an increased incidence of metabolic disease including type 2 diabetes mellitus. Epidemiological, cross-sectional and prospective studies suggest that two of the AAPs, olanzapine and clozapine, cause the most dramatic weight gain and metabolic impairments including increased fasting glucose, insulin and triglycerides. Relative to the other AAPs, both olanzapine and clozapine exhibit a particularly high antagonistic affinity for histamine and muscarinic receptors which have been hypothesized as mediators of the reported increase in weight and glucose abnormalities. In this article, we review the current evidence for the AAP associated weight gain and abnormal glucose metabolism. We postulate that the effects of the AAPs on food intake and peripheral metabolism are initially independently regulated but with increasing body adiposity, the early AAP-induced impairments in peripheral metabolism will be exacerbated, thereby establishing a vicious cycle such that the effects of the AAP are magnified by the known pathophysiological consequences of obesity. Furthermore, we examine how inhibition of the histaminergic pathway may mediate increases in food intake and the potential role of the vagus nerve in the reported peripheral metabolic effects.