Olanzapine-depot administration induces time-dependent changes in adipose tissue endocrine function in rats

Potent synergistic effects of dulaglutide and food restriction in prevention of olanzapine-induced metabolic adverse effects in a rodent model

BACKGROUND

Antipsychotics are indispensable in the treatment of severe mental illneses, however adverse metabolic effects including diabetes, weight gain, dyslipidemia, and related cardiovascular morbidity are common, and current pharmacological strategies for their management are unsatisfactory. Glucagon-like 1 peptide receptor agonists (GLP-1 RAs) are approved for the treatment of type 2 diabetes and obesity hold promise for the management of antipsychotic-associated adverse metabolic effects.

METHODS

To characterize the molecular effects and identify biomarkers for GLP-1 RA preventive treatment, Sprague-Dawley female rats were treated with long-acting formulations of the antipsychotic olanzapine and the GLP-1 RA dulaglutide for 8 days. A pair-feeding protocol evaluated the combined effects of dulaglutide and food restriction on an olanzapine-induced metabolic phenotype. Body weight and food consumption were recorded. Biochemical analysis included a lipid profile, a spectrum of gastrointestinal and adipose tissue-derived hormones, and fibroblast growth factor 21 serum levels.

RESULTS

Olanzapine induced hyperphagia, weight gain, increased serum triglycerides and HDL cholesterol. Food restriction affected the OLA-induced phenotype but not serum markers. Dulaglutide led to a modest decrease in food intake, with no effect on weight gain, and did not reverse the OLA-induced changes in serum lipid parameters. Concomitant dulaglutide and food restriction resulted in weight loss, decreased feed efficiency, and lower total and HDL cholesterol.

CONCLUSIONS

A combined strategy of dulaglutide and food restriction manifested a massive synergistic benefit. GLP-1RAs represent a promising strategy and deserve thorough future research. Our findings underline the potential importance of lifestyle intervention in addition to GLP-1 RA treatment.

Olanzapine, but not haloperidol, exerts pronounced acute metabolic effects in the methylazoxymethanol rat model

AIM

Widely used second-generation antipsychotics are associated with adverse metabolic effects, contributing to increased cardiovascular mortality. To develop strategies to prevent or treat adverse metabolic effects, preclinical models have a clear role in uncovering underlying molecular mechanisms. However, with few exceptions, preclinical studies have been performed in healthy animals, neglecting the contribution of dysmetabolic features inherent to psychotic disorders.

METHODS

In this study, methylazoxymethanol acetate (MAM) was prenatally administered to pregnant Sprague-Dawley rats at gestational day 17 to induce a well-validated neurodevelopmental model of schizophrenia mimicking its assumed pathogenesis with persistent phenotype. Against this background, the dysmetabolic effects of acute treatment with olanzapine and haloperidol were examined in female rats.

RESULTS

Prenatally MAM-exposed animals exhibited several metabolic features, including lipid disturbances. Half of the MAM rats exposed to olanzapine had pronounced serum lipid profile alteration compared to non-MAM controls, interpreted as a reflection of a delicate MAM-induced metabolic balance disrupted by olanzapine. In accordance with the drugs' clinical metabolic profiles, olanzapine-associated dysmetabolic effects were more pronounced than haloperidol-associated dysmetabolic effects in non-MAM rats and rats exposed to MAM.

CONCLUSION

Our results demonstrate metabolic vulnerability in female prenatally MAM-exposed rats, indicating that findings from healthy animals likely provide an underestimated impression of metabolic dysfunction associated with antipsychotics. In the context of metabolic disturbances, neurodevelopmental models possess a relevant background, and the search for adequate animal models should receive more attention within the field of experimental psychopharmacology.

Metabolic Hormones in Schizophrenia Patients with Antipsychotic-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a common complication of schizophrenia that is quite exacerbated by long-term use of (atypical) antipsychotics. The mechanism of MetS has neuronal, neuroendocrine, and neuroimmunological components and shows some overlap with those of aspects of schizophrenia. We examined 195 patients with schizophrenia (90 with and 105 without MetS) for the association of serum levels of ghrelin, insulin, and leptin with metabolic abnormalities. Serum glucose levels and lipid profiles were routinely measured with colorimetric enzymatic methods and hormone levels with multiplex analyzers. Leptin levels were highly significantly increased (p < 0.001) in people with MetS (9.966 [5.882; 21.496] vs. 6.35 [2.005; 11.753], Me [Q1; Q3]) and ghrelin levels were actually significantly decreased (p = 0.045). Insulin levels did not differ significantly between those with and without MetS (p = 0.162). In Spearman’s correlation analysis between the hormone levels, body characteristics, and biochemical parameters, significant correlations were seen somewhat more often in people without MetS than in those with MetS and also less often for ghrelin than for the other hormones. We conclude that evidence exists for a role in the development of MetS especially for leptin, but that less is supporting a role for ghrelin.

Increased growth hormone secretagogue receptor-1a (GHSR-1a) in hypothalamus during olanzapine treatment in rats

Weight gain is the one of the most important factors which increases global burden of psychiatric disorder. Second-generation antipsychotics, olanzapine (Olz) and valproic acid (Vpa) in particular, are held responsible for weight gain. However, it is still uncertain how these drugs cause this. Thus, the rats selected for the experiment were randomly divided into 3 groups. The 1st group received only 0.5 ml saline solution intraperitoneally (n = 20, control group); the second group was given 200 mg / kg Vpa intraperitoneally (n = 20, Vpa group) and 2 mg / kg Olz was given intraperitoneally to the 3rd group (n = 20, Olz group) between 8 and 10 am for 30 days. We examined serum leptin, adiponectin, resistin, TNF-α, IL-6, ghrelin level and, the amount of ghrelin secreting cells in the stomach and growth hormone secretagogue receptor-1a (GHSR-1a, ghrelin receptor) expression in the hypothalamus. The hypothalamic GHS-1a receptor index was significantly higher in the Olz group compared with the control group and Vpa group (p = 0.036 and p = 0.016 respectively). Ghrelin immune positive cell index in stomach was statistically significantly lower in the Vpa group compared with the control and Olz groups (p = 0.028 and p = 0.013 respectively) There was no difference between the groups in terms of serum leptin, resistin, IL-6 and ghrelin levels. In the Vpa group, a statistically significant increase was found in serum adiponectin level compared with both the control group and the Olz group (p = 0009 and p = 0024 respectively) and, significant decrease was found in serum TNF-α level compared to Olz group (p = 0007). In conclusion, we found that the main cause of weight gain in Olz use was the increase in the number of hypothalamic ghrelin receptors. Investigating the mechanism by which Olz increases the number of ghrelin receptors may help to develop effective treatment strategies in preventing obesity in psychiatric patients.

GLP-1 agonists: superior for mind and body in antipsychotic-treated patients?

Antipsychotics (APDs) represent a core treatment for severe mental disorders (SMEs). Providing symptomatic relief, APDs do not exert therapeutic effects on another clinically significant domain of serious mental disorders, cognitive impairment. Moreover, adverse metabolic effects (diabetes, weight gain, dyslipidemia, and increased cardiovascular risk) are common during treatment with APDs. Among pharmacological candidates reversing APD-induced metabolic adverse effects, glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs), approved for both diabetes and recently for obesity treatment, stand out due to their favorable effects on peripheral metabolic parameters. Interestingly, GLP-1 RAs are also proposed to have pro-cognitive effects. Particularly in terms of dual therapeutic mechanisms potentially improving both central nervous system (CNS) deficits and metabolic burden, GLP-1 RAs open a new perspective and assume a clinically advantageous position.

The second-generation antipsychotic drug aripiprazole modulates the serotonergic system in pancreatic islets and induces beta cell dysfunction in female mice

AIMS/HYPOTHESIS

Second-generation antipsychotic (SGA) drugs have been associated with the development of type 2 diabetes and the metabolic syndrome in patients with schizophrenia. In this study, we aimed to investigate the effects of two different SGA drugs, olanzapine and aripiprazole, on metabolic state and islet function and plasticity.

METHODS

We analysed the functional adaptation of beta cells in 12-week-old B6;129 female mice fed an olanzapine- or aripiprazole-supplemented diet (5.5-6.0 mg kg^-1 day^-1) for 6 months. Glucose and insulin tolerance tests, in vivo glucose-stimulated insulin secretion and indirect calorimetry were performed at the end of the study. The effects of SGAs on beta cell plasticity and islet serotonin levels were assessed by transcriptomic analysis and immunofluorescence. Insulin secretion was assessed by static incubations and Ca²⁺ fluxes by imaging techniques.

RESULTS

Treatment of female mice with olanzapine or aripiprazole for 6 months induced weight gain (p<0.01 and p<0.05, respectively), glucose intolerance (p<0.01) and impaired insulin secretion (p<0.05) vs mice fed a control chow diet. Aripiprazole, but not olanzapine, induced serotonin production in beta cells vs controls, likely by increasing tryptophan hydroxylase 1 (TPH1) expression, and inhibited Ca²⁺ flux. Of note, aripiprazole increased beta cell size (p<0.05) and mass (p<0.01) vs mice fed a control chow diet, along with activation of mechanistic target of rapamycin complex 1 (mTORC1)/S6 signalling, without preventing beta cell dysfunction.

CONCLUSIONS/INTERPRETATION

Both SGAs induced weight gain and beta cell dysfunction, leading to glucose intolerance; however, aripiprazole had a more potent effect in terms of metabolic alterations, which was likely a result of its ability to modulate the serotonergic system. The deleterious metabolic effects of SGAs on islet function should be considered while treating patients as these drugs may increase the risk for development of the metabolic syndrome and diabetes.

Early Lipid Metabolic Effects of the Anti-Psychotic Drug Olanzapine on Weight Gain and the Associated Gene Expression

BACKGROUND

Atypical antipsychotics such as olanzapine often cause metabolic side effects such as obesity and diabetes, leading to an increased risk of nonalcoholic fatty liver disease. The aim of the present study was to investigate the effects of olanzapine treatment on hepatic lipid metabolism and its possible relationship with adipose tissue status.

METHODS

Using a female rat model, we investigated the effects of chronic olanzapine administration on the regulation of carbohydrate and lipid metabolism including lipid biosynthesis, oxidation, efflux, and lipolysis in liver and adipose tissue.

RESULTS

The body weight, liver mass and visceral adiposity after olanzapine treatment (2 mg/kg) for five weeks were not significantly different compared with vehicle controls. The serum level of triglycerides was higher in the vehicle controls than in olanzapine-treated rats. Unexpectedly, olanzapine treatment did not reduce glucose tolerance in our model. The expression of functional thermogenic protein uncoupling protein 1 (UCP1) was increased in brown adipose tissue (BAT) of the olanzapine group. Additionally, olanzapine treatment also reduced adipose inflammation in white adipose tissue (WAT). The transcription factor sterol regulatory element-binding protein (SREBP)-1c, a key early regulator of lipogenesis, was downregulated following olanzapine treatment. The expression of genes related to the triglycerides synthesis apparatus in the liver was upregulated in the olanzapine group. Olanzapine treatment induced genes involved in PPAR-α signaling and mitochondrial fatty acid oxidation in response to increased ATGL-mediated lipolysis in the liver.

CONCLUSION

Together, our findings suggest a complicated link between olanzapine therapy and metabolic disturbance and may garner interest in assessing the action of antipsychotic-induced metabolic disturbances.

Interacting effects of the MAM model of schizophrenia and antipsychotic treatment: Untargeted proteomics approach in adipose tissue

Schizophrenia is a severe neuropsychiatric disease associated with substantially higher mortality. Reduced life expectancy in schizophrenia relates to an increased prevalence of metabolic disturbance, and antipsychotic medication is a major contributor. Molecular mechanisms underlying adverse metabolic effects of antipsychotics are not fully understood; however, adipose tissue homeostasis deregulation appears to be a critical factor. We employed mass spectrometry-based untargeted proteomics to assess the effect of chronic olanzapine, risperidone, and haloperidol treatment in visceral adipose tissue of prenatally methylazoxymethanol (MAM) acetate exposed rats, a well-validated neurodevelopmental animal model of schizophrenia. Bioinformatics analysis of differentially expressed proteins was performed to highlight the pathways affected by MAM and the antipsychotics treatment. MAM model was associated with the deregulation of the TOR (target of rapamycin) signalling pathway. Notably, alterations in protein expression triggered by antipsychotics were observed only in schizophrenia-like MAM animals where we revealed hundreds of affected proteins according to our two-fold threshold, but not in control animals. Treatments with all antipsychotics in MAM rats resulted in the downregulation of mRNA processing and splicing, while drug-specific effects included among others upregulation of insulin resistance (olanzapine), upregulation of fatty acid metabolism (risperidone), and upregulation of nucleic acid metabolism (haloperidol). Our data indicate that deregulation of several energetic and metabolic pathways in adipose tissue is associated with APs administration and is prominent in MAM schizophrenia-like model but not in control animals.

Effect of liraglutide on neural and peripheral markers of metabolic function during antipsychotic treatment in rats

BACKGROUND

Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist that prevents metabolic side effects of the antipsychotic drugs (APDs) olanzapine and clozapine through unknown mechanisms.

AIM

This study aimed to investigate the effect of chronic APD and liraglutide co-treatment on key neural and peripheral metabolic signals, and acute liraglutide co-treatment on clozapine-induced hyperglycaemia.

METHODS

In study 1, rats were administered olanzapine (2 mg/kg), clozapine (12 mg/kg), liraglutide (0.2 mg/kg), olanzapine + liraglutide co-treatment, clozapine + liraglutide co-treatment or vehicle for six weeks. Feeding efficiency was examined weekly. Examination of brain tissue (dorsal vagal complex (DVC) and mediobasal hypothalamus (MBH)), plasma metabolic hormones and peripheral (liver and kidney) cellular metabolism and oxidative stress was conducted. In study 2, rats were administered a single dose of clozapine (12 mg/kg), liraglutide (0.4 mg/kg), clozapine + liraglutide co-treatment or vehicle. Glucose tolerance and plasma hormone levels were assessed.

RESULTS

Liraglutide co-treatment prevented the time-dependent increase in feeding efficiency caused by olanzapine, which plateaued by six weeks. There was no effect of chronic treatment on melanocortinergic, GABAergic, glutamatergic or endocannabionoid markers in the MBH or DVC. Peripheral hormones and cellular metabolic markers were unaltered by chronic APD treatment. Acute liraglutide co-treatment was unable to prevent clozapine-induced hyperglycaemia, but it did alter catecholamine levels.

CONCLUSION

The unexpected lack of change to central and peripheral markers following chronic treatment, despite the presence of weight gain, may reflect adaptive mechanisms. Further studies examining alterations across different time points are required to continue to elucidate the mechanisms underlying the benefits of liraglutide on APD-induced metabolic side effects.

Impaired hormonal regulation of appetite in schizophrenia: A narrative review dissecting intrinsic mechanisms and the effects of antipsychotics

Cardiometabolic diseases are the main contributor of reduced life expectancy in patients with schizophrenia. It is now widely accepted that antipsychotic treatment plays an important role in the development of obesity and its consequences. However, some intrinsic mechanisms need to be taken into consideration. One of these mechanisms might be related to impaired hormonal regulation of appetite in this group of patients. In this narrative review, we aimed to dissect impairments of appetite-regulating hormones attributable to intrinsic mechanisms and those related to medication effects. Early hormonal alterations that might be associated with intrinsic mechanisms include low levels of leptin and glucagon-like peptide-1 (GLP-1) together with elevated insulin levels in first-episode psychosis (FEP) patients. However, evidence regarding low GLP-1 levels in FEP patients is based on one large study. In turn, multiple-episode schizophrenia patients show elevated levels of insulin, leptin and orexin A together with decreased levels of adiponectin. In addition, patients receiving olanzapine may present with low ghrelin levels. Post mortem studies have also demonstrated reduced number of neuropeptide Y neurons in the prefrontal cortex of patients with schizophrenia. Treatment with certain second-generation antipsychotics may also point to these alterations. Although our understanding of hormonal regulation of appetite in schizophrenia has largely been improved, several limitations and directions for future studies need to be addressed. This is of particular importance since several novel pharmacological interventions for obesity and diabetes have already been developed and translation of these developments to the treatment of cardiometabolic comorbidities in schizophrenia patients is needed.

Metabolic profile of methylazoxymethanol model of schizophrenia in rats and effects of three antipsychotics in long-acting formulation

Mortality in psychiatric patients with severe mental illnesses reaches a 2-3 times higher mortality rate compared to the general population, primarily due to somatic comorbidities. A high prevalence of cardiovascular morbidity can be attributed to the adverse metabolic effects of atypical antipsychotics (atypical APs), but also to metabolic dysregulation present in drug-naïve patients. The metabolic aspects of neurodevelopmental schizophrenia-like models are understudied. This study evaluated the metabolic phenotype of a methylazoxymethanol (MAM) schizophrenia-like model together with the metabolic effects of three APs [olanzapine (OLA), risperidone (RIS) and haloperidol (HAL)] administered via long-acting formulations for 8 weeks in female rats. Body weight, feed efficiency, serum lipid profile, gastrointestinal and adipose tissue-derived hormones (leptin, ghrelin, glucagon and glucagon-like peptide 1) were determined. The lipid profile was assessed in APs-naïve MAM and control cohorts of both sexes. Body weight was not altered by the MAM model, though cumulative food intake and feed efficiency was lowered in the MAM compared to CTR animals. The effect of the APs was also present; body weight gain was increased by OLA and RIS, while OLA induced lower weight gain in the MAM rats. Further, the MAM model showed lower abdominal adiposity, while OLA increased it. Serum lipid profile revealed MAM model-induced alterations in both sexes; total, HDL and LDL cholesterol levels were increased. The MAM model did not exert significant alterations in hormonal parameters except for elevation in leptin level. The results support intrinsic metabolic dysregulation in the MAM model in both sexes, but the MAM model did not manifest higher sensitivity to metabolic effects induced by antipsychotic treatment.

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.

Combination of Olanzapine Pamoate with Melatonin and Metformin: Quantitative Changes in Rat Adipose Tissue

Olanzapine is one of the atypical antipsychotics widely used in the treatment of schizophrenia and has been associated with metabolic changes as adverse effects, including hyperglycemia, dyslipidemia, and weight gain. In a batch of adult female Wistar rats, we studied the prolonged-release intramuscular olanzapine pamoate induced quantitative changes of visceral and subcutaneous adipose tissue. We also assessed the effects of the combinations of olanzapine pamoate with melatonin, metformin, and melatonin plus metformin, administered by gastric gavage. A higher mean weight of the visceral and subcutaneous adipose tissue per animal was noted in the olanzapine pamoate exposed group compared to controls. The association with melatonin, metformin, or the combination of melatonin with metformin attenuated the olanzapine-induced adipose deposit tissue growth. The effect was more pronounced for the combination of olanzapine with melatonin and metformin. Because most of the results were not statistically significant we can deduce that in the chronic experiment, adaptive type modifications of the receptors on which both olanzapine and melatonin act can occur.

Adipose tissue as a target for second-generation (atypical) antipsychotics: A molecular view

Schizophrenia is a neuropsychiatric disorder that chronically affects 21 million people worldwide. Second-generation antipsychotics (SGAs) are the cornerstone in the management of schizophrenia. However, despite their efficacy in counteracting both positive and negative symptomatology of schizophrenia, recent clinical observations have described an increase in the prevalence of metabolic disturbances in patients treated with SGAs, including abnormal weight gain, hyperglycemia and dyslipidemia. While the molecular mechanisms responsible for these side-effects remain poorly understood, increasing evidence points to a link between SGAs and adipose tissue depots of white, brown and beige adipocytes. In this review, we survey the present knowledge in this area, with a particular focus on the molecular aspects of adipocyte biology including differentiation, lipid metabolism, thermogenic function and the browning/beiging process.

Olanzapine exposure diminishes perfusion and decreases volume of sensorimotor cortex in rats

BACKGROUND

Olanzapine is a frequently used atypical antipsychotic drug known to exert structural brain alterations in animals. This study investigated whether chronic olanzapine exposure alters regional blood brain perfusion assessed by Arterial Spin Labelling (ASL) magnetic resonance imaging (MRI) in a validated model of olanzapine-induced metabolic disturbances. An effect of acute olanzapine exposure on brain perfusion was also assessed for comparison.

METHODS

Adult Sprague-Dawley female rats were treated by intramuscular depot olanzapine injections (100 mg/kg every 14 days) or vehicle for 8 weeks. ASL scanning was performed on a 9.4 T Bruker BioSpec 94/30USR scanner under isoflurane anesthesia. Serum samples were used to assay leptin and TNF-α level while brains were sliced for histology. Another group received only one non-depot intraperitoneal dose of olanzapine (7 mg/kg) during MRI scanning, thus exposing its acute effect on brain perfusion.

RESULTS

Both acute and chronic dosing of olanzapine resulted in decreased perfusion in the sensorimotor cortex, while no effect was observed in the piriform cortex or hippocampus. Furthermore, in the chronically treated group decreased cortex volume was observed. Chronic olanzapine dosing led to increased body weight, adipose tissue mass and leptin level, confirming its expected metabolic effects.

CONCLUSION

This study demonstrates region-specific decreases in blood perfusion associated with olanzapine exposure present already after the first dose. These findings extend our understanding of olanzapine-induced functional and structural brain changes.

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.

Metabolic and endocrinal effects of N-desmethyl-olanzapine in mice with obesity: Implication for olanzapine-associated metabolic changes

Clinical use of the antipsychotic drug olanzapine (OLA) is associated with metabolic side effects to variable degrees. N-desmethyl-olanzapine (DMO) is one major metabolite of OLA, but its potential involvement in the metabolic responses remains unclear. Here we examined whether DMO can directly impact the metabolic, endocrinal and inflammatory parameters under conditions of metabolic disturbance. DMO administration (2 mg/kg, i.g.) to high-fat diet induced obesity mice for 4 weeks induced a remarkable loss of body weight and fat mass. DMO improved insulin resistance and energy expenditure in mice, but had no significant effects on dyslipidemia or hepatic steatosis. Moreover, DMO induced morphological changes in the white adipose tissue, accompanied by reduced interleukin-1β (IL-1β) production and increased UCP1 expression. These findings demonstrate that DMO is devoid of the metabolic side effects commonly observed for OLA during obesity, which suggests that the N-desmethyl metabolism may function to regulate the metabolic responses to OLA.

Meta-analysis of ghrelin alterations in schizophrenia: Effects of olanzapine

OBJECTIVE

Schizophrenia is associated with an increased prevalence of the metabolic syndrome. Patients receiving antipsychotic medications, including olanzapine, are at further risk. Ghrelin is an appetite-stimulating peptide hormone, although whether blood levels are altered by antipsychotic treatment, remains unclear. We performed a systematic review and meta-analysis comparing blood ghrelin levels in patients with schizophrenia before and after treatment with olanzapine.

METHOD

Two authors independently searched major electronic databases from inception until February 2018 for studies measuring blood ghrelin levels among patients with schizophrenia before and after olanzapine therapy. Random effects meta-analysis calculating standardized mean difference (SMD) and 95% confidence intervals (CI) and meta-regression analyses were performed.

RESULTS

Six studies met the inclusion criteria. Across these studies, there were 111 patients with schizophrenia (mean age 40, 85% male, baseline BMI 22, and endpoint BMI 23). Olanzapine treatment (mean [standard deviation] duration = 12.3 [7.6] weeks) was associated with a significant decrease in blood ghrelin levels with a medium effect size (SMD = -0.48, 95% CI -0.88 to -0.08, p = 0.018). Age, sex, baseline BMI, geography, olanzapine dose and duration, year of publication, study quality, inpatient status, and antipsychotic washout did not moderate this association.

CONCLUSION

Our results suggest that in patients with schizophrenia, olanzapine therapy is associated with decreased blood ghrelin levels, a paradoxical phenomenon known to occur in obesity. Future studies should investigate the contribution of dietary factors (e.g., caloric intake) and physical activity to this association, as well as the effects of other antipsychotics on ghrelin levels.

One-Year Treatment with Olanzapine Depot in Female Rats: Metabolic Effects

BACKGROUND

Antipsychotic drugs can negatively affect the metabolic status of patients, with olanzapine as one of the most potent drugs. While patients are often medicated for long time periods, experiments in rats typically run for 1 to 12 weeks, showing olanzapine-related weight gain and increased plasma lipid levels, with transcriptional upregulation of lipogenic genes in liver and adipose tissue. It remains unknown whether metabolic status will deteriorate with time.

METHODS

To examine long-term metabolic effects, we administered intramuscular long-acting injections of olanzapine (100 mg/kg BW) or control substance to female rats for up to 13 months.

RESULTS

Exposure to olanzapine long-acting injections led to rapid weight gain, which was sustained throughout the experiment. At 1, 6, and 13 months, plasma lipid levels were measured in separate cohorts of rats, displaying no increase. Hepatic transcription of lipid-related genes was transiently upregulated at 1 month. Glucose and insulin tolerance tests indicated insulin resistance in olanzapine-treated rats after 12 months.

CONCLUSION

Our data show that the continuous increase in body weight in response to long-term olanzapine exposure was accompanied by surprisingly few concomitant changes in plasma lipids and lipogenic gene expression, suggesting that adaptive mechanisms are involved to reduce long-term metabolic adverse effects of this antipsychotic agent in rats.

Olanzapine Induced Dysmetabolic Changes Involving Tissue Chromium Mobilization in Female Rats

Atypical antipsychotics, such as olanzapine, are commonly prescribed to patients with schizophrenic symptoms and other psychiatric disorders. However, weight gain and metabolic disturbance cause adverse effects, impair patient compliance and limit clinical utility. Thus, a better understanding of treatment-acquired adverse effects and identification of targets for therapeutic intervention are believed to offer more clinical benefits for patients with schizophrenia. Beyond its nutritional effects, studies have indicated that supplementation of chromium brings about beneficial outcomes against numerous metabolic disorders. In this study, we investigated whether olanzapine-induced weight gain and metabolic disturbance involved chromium dynamic mobilization in a female Sprague-Dawley rat model, and whether a dietary supplement of chromium improved olanzapine-acquired adverse effects. Olanzapine medicated rats experienced weight gain and adiposity, as well as the development of hyperglycemia, hyperinsulinemia, insulin resistance, hyperlipidemia, and inflammation. The olanzapine-induced metabolic disturbance was accompanied by a decrease in hepatic Akt and AMP-activated Protein Kinase (AMPK) actions, as well as an increase in serum interleukin-6 (IL-6), along with tissue chromium depletion. A daily intake of chromium supplements increased tissue chromium levels and thermogenic uncoupling protein-1 (UCP-1) expression in white adipose tissues, as well as improved both post-olanzapine weight gain and metabolic disturbance. Our findings suggest that olanzapine medicated rats showed a disturbance of tissue chromium homeostasis by inducing tissue depletion and urinary excretion. This loss may be an alternative mechanism responsible for olanzapine-induced weight gain and metabolic disturbance.

Leptin/Adiponectin ratio as a potential biomarker for metabolic syndrome in patients with schizophrenia

OBJECTIVE

Leptin and adiponectin are adipokines which have opposing roles in the development of insulin resistance and metabolic syndrome (MetS). Leptin/adiponectin ratio (L/A ratio) has been proposed as a good biomarker for MetS in general population. This study aimed to compare the strength of association between MetS and leptin, adiponectin and L/A ratio, as well as to assess their performance to diagnose MetS in patients with schizophrenia.

METHODS

Patients diagnosed with DSM-IV schizophrenia and under clozapine or olanzapine monotherapy for at least six months were recruited. We used the modified ATP III criteria for Asians to evaluate subjects for a diagnosis of MetS.

RESULTS

We recruited 262 study subjects with schizophrenia, and classified them into those with MetS (n = 87) and those without MetS (n = 175). Leptin level was positively correlated with BMI, waist circumference, and insulin level. Adiponectin level was negatively correlated with most metabolic parameters, except glucose level. L/A ratio was positively correlated with most metabolic parameters, except levels of glucose and HDL-C. Significant gender differences existed in leptin levels, adiponectin levels, and L/A ratio. Without and with adjustment of age and gender, binary logistic regression analysis showed that leptin level, adiponectin level, and L/A ratio were significantly associated with MetS. The area under curve (AUC) of L/A ratio and leptin level for MetS was 0.744 (95% CI = 0.685-0.802) and 0.666 (95% CI = 0.601-0.731). The AUC of adiponectin level for the absence of MetS was 0.717 (95% CI = 0.655-0.780). The discriminative strength of L/A ratio for MetS was better in men than in women.

CONCLUSIONS

The present study results suggest that L/A ratio may be a preferential marker of metabolic syndrome in patients with schizophrenia compared to leptin or adiponectin alone.

Aripiprazole-induced adverse metabolic alterations in polyI:C neurodevelopmental model of schizophrenia in rats

Schizophrenia appears to be linked to higher incidence of metabolic syndrome even in the absence of antipsychotic treatment. Atypical antipsychotics substantially differ in their propensity to induce metabolic alterations. Aripiprazole is considered to represent an antipsychotic drug with low risk of metabolic syndrome development. The aim of this study was to evaluate metabolic phenotype of neurodevelopmental polyI:C rat model and assess metabolic effects of chronic aripiprazole treatment with regard to complex neuroendocrine regulations of energy homeostasis. Polyinosinic:polycytidylic acid (polyI:C) was administered subcutaneously at a dose of 8 mg/kg in 10 ml on gestational day 15 to female Wistar rats. For this study 20 polyI:C and 20 control adult male offspring were used, randomly divided into 2 groups per 10 animals for chronic aripiprazole treatment and vehicle. Aripiprazole (5 mg/kg, dissolved tablets, ABILIFY^®) was administered once daily via oral gavage for a month. Altered lipid profile in polyI:C model was observed and a trend towards different dynamics of weight gain in polyI:C rats was noted in the absence of significant antipsychotic treatment effect. PolyI:C model was not associated with changes in other parameters i.e. adipokines, gastrointestinal hormones and cytokines levels. Aripiprazole did not influence body weight but it induced alterations in neurohumoral regulations. Leptin and GLP-1 serum levels were significantly reduced, while ghrelin level was elevated. Furthermore aripiprazole decreased serum levels of pro-inflammatory cytokines. Our data indicate dysregulation of adipokines and gastrointestinal hormones present after chronic treatment with aripiprazole which is considered metabolically neutral in the polyI:C model of 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.

Time-dependent effects of olanzapine treatment on the expression of histidine decarboxylase, H1 and H3 receptor in the rat brain: The roles in olanzapine-induced obesity

Antipsychotic treatment, particularly olanzapine and clozapine, induces severe obesity. The Histamine H1 receptor is considered to be an important contributor to olanzapine-induced obesity, however how olanzapine modulates the histaminergic system is not sufficiently understood. This study examined the effect of olanzapine on key molecules of the histaminergic system, including histidine decarboxylase (HDC), H1 receptor (H1R) and H3 receptor (H3R), in the brain at different stages of olanzapine-induced obesity. During short-term treatment (8-day), olanzapine increased hypothalamic HDC mRNA expression and H1R binding in the arcuate nucleus (Arc) and ventromedial hypothalamus (VMH), without changing H3R binding density. HDC mRNA and Arc H1R binding were positively correlated with increased food intake, feeding efficiency and weight gain. When the treatment was extended to 16 and 36 days, H1R binding was increased not only in the hypothalamic Arc and VMH but also in the brainstem dorsal vagal complex (DVC). The H1R bindings in the Arc, VMH and DVC were positively correlated with weight gain induced by olanzapine treatment. However, the expression of HDC and H3R mRNA was not increased. These results suggest that olanzapine time-dependently modulates histamine neurotransmission, which suggested the different neuronal mechanisms underlying different stages of weight gain development. Treatment targeting the H1R may be effective for both short- and long-term olanzapine-induced weight gain.

Prevention of the adverse effects of olanzapine on lipid metabolism with the antiepileptic zonisamide

BACKGROUND

Atypical antipsychotic drugs, particularly olanzapine, represent a mainstay in the treatment of psychoses; however, their use is commonly associated with weight gain and diabetes. The aim of this study was to determine whether combined administration of olanzapine and zonisamide can be used to prevent olanzapine-induced metabolic disturbances.

METHODS AND RESULTS

These experiments involved female Sprague Dawley rats (n = 6-8/group) that were administered olanzapine, either acutely (6 mg/kg, s. c) or via continuous osmotic minipump infusion (6 mg/kg/day for 6 or 14 days), in combination with zonisamide (26 mg/kg/day,i.p.). Continuous infusion of olanzapine induced accumulation of adipose tissue and an associated reduction in stimulated lipolysis and reduced protein expression of CGI-58, a critical co-activator of ATGL. Olanzapine treatment caused a preferential shift toward carbohydrate oxidation (or reduced fat oxidation), elevated blood triglycerides and a reduction in locomotor activity. Olanzapine had a direct effect on glucose regulation, causing rapid hyperglycemia, and a reduction in glucose tolerance and insulin sensitivity. Continuous administration of olanzapine caused significant hyperinsulinemia and a significant reduction in insulin sensitivity. Zonisamide did not affect the impact of olanzapine on glucose homeostasis. On the other hand, co-administration of olanzapine with zonisamide completely ameliorated olanzapine-mediated shifts in lipid metabolism resulting in a normalization of olanzapine-induced weight gain.

CONCLUSION

These data collectively show an impact of olanzapine on body weight and lipid metabolism, which is ameliorated by co-administration with zonisamide. These findings suggest that a combined olanzapine and zonisamide approach might reduce weight gain, but will not provide protection against olanzapine-induced glucose intolerance.

Depot risperidone-induced adverse metabolic alterations in female rats

Atypical antipsychotics are associated with adverse metabolic effects including weight gain, increased adiposity, dyslipidaemia, alterations in glucose metabolism and insulin resistance. Increasing evidence suggests that metabolic dysregulation precedes weight gain development. The aim of this study was to evaluate alterations in adipokines, hormones and basic serum biochemical parameters induced by chronic treatment with depot risperidone at two doses (20 and 40 mg/kg) in female Sprague-Dawley rats. Dose-dependent metabolic alterations induced by risperidone after 6 weeks of treatment were revealed. Concomitant to weight gain and increased liver weight, an adverse lipid profile with an elevated triglyceride level was observed in the high exposure group, administered a 40 mg/kg dose repeatedly, while the low dose exposure group, administered a 20 mg/kg dose, developed weight gain without alterations in the lipid profile and adipokine levels. An initial peak in leptin serum level after the higher dose was observed in the absence of weight gain. This finding may indicate that the metabolic alterations observed in this study are not consequent to body weight gain. Taken together, these data may support the primary effects of atypical antipsychotics on peripheral tissues.