The protein kinase D1-mediated inflammatory pathway is involved in olanzapine-induced impairment of skeletal muscle insulin signaling in rats

Olanzapine-Induced Weight Gain and Glycolipid Metabolism Aberrations in First-Episode and Antipsychotic-Naïve Schizophrenia Patients: A Longitudinal Study

OBJECTIVE

Limited research has delved into the comprehensive impact of monotherapy on weight and glycolipid metabolism in schizophrenia (SCZ) patients. Our study aims to longitudinally investigate the multidimensional effects of olanzapine (OLA) monotherapy on weight and glycolipid metabolism in first-episode and antipsychotic-naïve (FEAN) SCZ patients.

METHODS

A total of 74 FEAN-SCZ patients were recruited, as well as 58 sex- and age-matched healthy controls. Eligible patients underwent a 4-week OLA treatment regimen, with weight assessments conducted at baseline and week 4. Moreover, lipid profiles and fasting plasma glucose (FPG) were measured at baseline and week 4. Insulin, leptin (LEP), and adiponectin (APN) levels were determined using enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

At baseline, FEAN-SCZ patients showed elevated levels of insulin, low-density lipoprotein (LDL), impaired insulin sensitivity, and reduced levels of APN compared to the healthy controls. Following 4-week OLA treatment, patients showed an increase in body mass index (BMI) of 0.96 kg/m2. Additionally, FPG, quantitative insulin sensitivity check index (QUICKI), HOMA-insulin sensitivity index (HOMA-ISI), and fasting plasma glucose to insulin ratio (G/I) displayed significant decreases, while insulin, HOMA-IR, and LEP levels showed significant increases. Stepwise regression analysis revealed that baseline FPG independently predicted the change in BMI after 4 weeks of OLA treatment.

CONCLUSION

FEAN-SCZ patients exhibited pre-existing alterations in glucose homeostasis. After 4 weeks of OLA treatment, SCZ patients experienced significant weight gain, deteriorating insulin resistance, and increased LEP levels. In addition, baseline FPG emerged as a predictor of BMI changes after 4 weeks of OLA treatment.

The mechanisms underlying olanzapine-induced insulin resistance via the brown adipose tissue and the therapy in rats

A rapid increase has been observed in insulin resistance (IR) incidence induced by a long-term olanzapine treatment with no better ways to avoid it. Our study aimed to demonstrate the mechanism underlying the olanzapine-induced insulin resistance and find appropriate drug interventions. In this study, firstly, we constructed rat insulin resistance model using a two-month gavage of olanzapine and used the main active ingredient mixture of Gegen Qinlian Decoction for the treatment. The activity of brown adipose tissue (BAT) was measured using the PET/CT scan, whereas Western blot and quantitative real-time PCR were used to detect the expression of GLUT4 and UCP1. The results showed that the long-term administration of olanzapine impaired glucose tolerance and produced insulin resistance in rats, while Gegen Qinlian Decoction could improve this side effect. The results of the PET/CT scan showed that the BAT activity in the insulin-resistant rats was significantly lower than that of the Gegen Qinlian Decoction treated rats. Also, the expression of GLUT4 and UCP1 in the insulin resistance group showed a significant decrease, which could be up-regulated by Gegen Qinliane Decoction treatment. The results of both in vivo and in vitro experiments were consistent. we demonstrated that the olanzapine could induce IR in vitro and in vivo by decreasing the expression of UCP1; thus, suppressing the thermogenesis of BAT and impairing glucose uptake. More importantly, we demonstrated a possible novel strategy to improve the olanzapine-induced IR by Gegen Qinlian Decoction.

Anthocyanins from Aristotelia chilensis Prevent Olanzapine-Induced Hepatic-Lipid Accumulation but Not Insulin Resistance in Skeletal Muscle Cells

Type 2 diabetes and obesity are major problems worldwide and dietary polyphenols have shown efficacy to ameliorate signs of these diseases. Anthocyanins from berries display potent antioxidants and protect against weight gain and insulin resistance in different models of diet-induced metabolic syndrome. Olanzapine is known to induce an accelerated form of metabolic syndrome. Due to the aforementioned, we evaluated whether delphinidin-3,5-O-diglucoside (DG) and delphinidin-3-O-sambubioside-5-O-glucoside (DS), two potent antidiabetic anthocyanins isolated from Aristotelia chilensis fruit, could prevent olanzapine-induced steatosis and insulin resistance in liver and skeletal muscle cells, respectively. HepG2 liver cells and L6 skeletal muscle cells were co-incubated with DG 50 μg/mL or DS 50 μg/mL plus olanzapine 50 μg/mL. Lipid accumulation was determined in HepG2 cells while the expression of p-Akt as a key regulator of the insulin-activated signaling pathways, mitochondrial function, and glucose uptake was assessed in L6 cells. DS and DG prevented olanzapine-induced lipid accumulation in liver cells. However, insulin signaling impairment induced by olanzapine in L6 cells was not rescued by DS and DG. Thus, anthocyanins modulate lipid metabolism, which is a relevant factor in hepatic tissue, but do not significantly influence skeletal muscle, where a potent antioxidant effect of olanzapine was found.