Olanzapine: a 5-year perspective

Mechanisms of adverse mammary effect induced by olanzapine and therapeutic interventions in rat model

BACKGROUND

Olanzapine antagonizes dopamine receptors and is prescribed to treat multiple psychiatric conditions. The main side effect of concern for olanzapine is weight gain and metabolic syndrome. Olanzapine induces hyperprolactinemia, however its effect on the mammary gland is poorly documented.

METHODS

Rats received olanzapine by gavage or in drinking water at 1, 3, and 6 mg/kg/day for 5-40 days or 100 days, with and without coadministration of bromocriptine or aripiprazole and using once daily or continuous administration strategies. Histomorphology of the mammary gland, concentrations of prolactin, estradiol, progesterone, and olanzapine in serum, mammary gland and adipose tissue, and mRNA and protein expressions of prolactin receptors were analyzed.

RESULTS

In adult and prepubescent female rats and male rats, olanzapine induced significant development of mammary glands in dose- and time-dependent manners, with histopathological hyperplasia of mammary ducts and alveoli with lumen dilation and secretion, marked increase of mammary prolactin receptor expression, a marker of breast tissue, and with mild increase of circulating prolactin. This side effect can be reversed after medication withdrawal, but long-term olanzapine treatment for 100 days implicated tumorigenic potentials indicated by usual ductal epithelial hyperplasia. Olanzapine induced mammary development was prevented with the coaddition of the dopamine agonist bromocriptine or partial agonist aripiprazole, or by continuous administration of medication instead of a once daily regimen.

CONCLUSIONS

These results shed light on the previously overlooked effect of olanzapine on mammary development and present experimental evidence to support current clinical management strategies of antipsychotic induced side effects in the breast.

The JAK/STAT3 signalling pathway regulated angiogenesis in an endothelial cell/adipose-derived stromal cell co-culture, 3D gel model

OBJECTIVES

The aim of the study was to investigate the role of the JAK/STAT3 signalling pathway in angiogenesis.

MATERIALS AND METHODS

The model established in vitro, involved a 3D collagen gel being implanted with endothelial cells (ECs) from red fluorescent protein-labelled mice, and adipose-derived stromal cells (ASCs) from green fluorescent protein-labelled mice. Phenomena of angiogenesis, after treatment by the inhibitor and the activator of JAK/STAT3 pathway respectively, were observed using confocal laser scanning microscopy. Transwell co-culture of ECs and ASCs was used to elucidate mechanisms.

RESULTS

Stattic, inhibitor of JAK/STAT3 pathway, attenuated angiogenesis in the model. In contrast, angiogenesis was promoted after treatment of Olanzapine, an activator. We found that protein levels of VEGFA and cyclin D1 were regulated by the JAK/STAT3 pathway, and flow cytometry further confirmed variations in cell cycle parameters of ECs and ASCs. Genes VEGFA/B, VEGFR2, MMP-2, MMP-9, IGF-1 and b-FGF were down-regulated by Stattic in ECs, while Olanzapine significantly up-regulated mRNA levels of these genes. As for ASCs, genes VEGFA, MMP-2, MMP-9, IGF-1 and b-FGF were modulated by the JAK/STAT3 pathway.

CONCLUSIONS

Angiogenesis in the 3D collagen gel was regulated by the JAK/STAT3 pathway which involved changes in vessel length, vessel diameter and sprout number. The underlying mechanism was that the JAK/STAT3 signalling pathway regulated angiogenesis by modulation of numbers of angiogenesis-related growth factors and by direct regulation of cell cycle.

Peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala: lack of association with weight gain in psychiatric inpatients treated with olanzapine or clozapine

BACKGROUND AND OBJECTIVE

Weight gain is a common problem of treatment with atypical antipsychotics. However, the dimension of body weight change differs interindividually, and various genetic factors are considered to be associated with this effect. Peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala polymorphism and its reported relationship to type 2 diabetes susceptibility and body mass accumulation prompted us to investigate the impact of this single nucleotide polymorphism (SNP) on antipsychotic-induced changes of body weight and body mass index (BMI) in a naturalistic study design.

METHODS

Included were 138 olanzapine- and 32 clozapine-treated psychiatric inpatients whose demographic data, medical anamnesis, and drug treatment were assessed at admission to hospital and 4 weeks thereafter. The PPARG Pro12Ala SNP was determined with a validated real-time PCR assay.

RESULTS

In contrast to previous investigations, we did not detect significant variations of weight gain among the different PPARG Pro12Ala genotypes.

CONCLUSION

Our results suggest that the examined polymorphism appears to play a minor or no role in clinical practice concerning antipsychotic drug-induced weight gain.

An exploratory analysis of factors associated with weight change in a 16-week trial of oral vs. orally disintegrating olanzapine: the PLATYPUS study

BACKGROUND

We conducted exploratory analyses of the data from a multinational, randomised study to identify factors associated with weight change after 16 weeks of treatment with standard olanzapine tablets (SOT) or sublingual orally disintegrating olanzapine (ODO).

METHODS

One hundred and forty nine outpatients who gained weight during prior SOT therapy were enrolled into the study and treated with ODO (N = 84) or SOT (N = 65). Exploratory analyses were conducted with the subset of compliant patients (ODO: n = 60; SOT: n = 47).

RESULTS

The decrease in the rate of weight gain at the end of study therapy (change from baseline) was greater in the ODO group than the SOT group (-0.59 kg/week vs. -0.38 kg/week, p = 0.0246). Age was negatively associated with weight change (p = 0.0203) in both treatment groups combined: patients gained 0.7 kg less for every 10 years of age. The least squares mean weight gain was lower with ODO than SOT in male patients (0.35 kg vs. 3.04 kg, p = 0.061), but not female patients and in American patients (0.55 kg vs. 6.21 kg, p < 0.0001), but not Canadian or Mexican patients.

CONCLUSIONS

Although not conclusive, these data suggest that ODO may be a reasonable treatment option for some patients who gain weight with SOT. Further research is required to confirm these findings.

The association of olanzapine-induced weight gain with peroxisome proliferator-activated receptor-gamma2 Pro12Ala polymorphism in patients with schizophrenia

Olanzapine is a second-generation antipsychotic that may cause weight gain and metabolic syndrome in some cases. The peroxisome proliferator-activated receptor (PPAR)-gamma is an important gene in the progress of type II diabetes and metabolic syndrome. In recent studies the polymorphism of the PPAR-gamma has been studied in type II diabetes mellitus, polycystic ovary syndrome, and insulin resistance syndrome. It is aimed to evaluate the association between polymorphism of PPAR-gamma gene and olanzapine-induced weight gain. Our study comprised 95 unrelated subjects who strictly met Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for schizophrenia, and all were of Turkish origin. All patients were evaluated with rating scales, and genetic analyses were performed. We found statistically significant differences between pretreatment and posttreatment body mass index and weight change in Pro12Ala polymorphism of PPAR-gamma2. Our results suggest that genetic polymorphism of PPAR might be important in olanzapine-induced weight gain and that genetic variance of people might be considered in antipsychotic medication selection.

Olanzapine increases RGS7 protein expression via stimulation of the Janus tyrosine kinase-signal transducer and activator of transcription signaling cascade

Atypical antipsychotics such as olanzapine have high affinity for multiple monoamine neurotransmitter receptors and are the mainstay of pharmacological therapy for treatment of schizophrenia. In addition to blocking monoamine receptors, these drugs also affect intracellular signaling cascades. We now report that 24-h treatment with 300 nM olanzapine causes desensitization of serotonin (5-HT)(2A) receptors in A1A1v cells, a rat cortical cell line, as indicated by a reduction in inositol phosphate accumulation following stimulation with a 5-HT(2A/2C) receptor agonist (-)-1-(2,5-dimethoxy-4-lodophenyl)-2-aminopropane HCl. Olanzapine treatment for 24 h increased the levels of 5-HT(2A) receptors in both cytosol (234 +/- 34% of control level) and membrane fractions (206 +/- 14% of control levels) and RGS7 proteins in both cytosol (193 +/- 32% of control levels) and membrane fractions (160 +/- 18% of control levels) as measured on Western blots. Increased phosphorylation of Janus tyrosine kinase (JAK) 2 and increased phosphorylation and nuclear translocation of signal transducer and activator of transcription (STAT) 3 with 24-h olanzapine treatment demonstrate activation of the JAK-STAT signaling cascade. Pretreatment with a JAK inhibitor, AG490 [alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide], prevented the olanzapine-induced increase in membrane RGS7 protein levels; AG490 alone had no effect on RGS7 protein levels. We verified that treatment with AG490 reduced phosphorylation of JAK2 and inhibited the nuclear localization of phospho-STAT3. Interestingly, treatment with the JAK inhibitor had no effect on 5-HT(2A) receptor protein levels. These data suggest that olanzapine-induced activation of the JAK-STAT signaling cascade causes increased expression of RGS7 protein, which in turn could mediate desensitization of 5-HT(2A) receptor signaling caused by olanzapine because RGS7 binds to Galpha(q) protein and accelerates GTP hydrolysis.