Pleiotropic effects of rosuvastatin on the glucose metabolism and the subcutaneous and visceral adipose tissue behavior in C57Bl/6 mice

MicroRNA-206 as a potential cholesterol-lowering drug is superior to statins in mice

Hypercholesterolemia is frequently intertwined with hepatosteatosis, hypertriglyceridemia, and hyperglycemia. This study is designed to assess the therapeutic efficacy of miR-206 in contrast to statins in the context of managing hypercholesterolemia in mice. We previously showed that miR-206 is a potent inhibitor of de novo lipogenesis (DNL), cholesterol synthesis, and gluconeogenesis in mice. Given that these processes occur within hepatocytes, we employed a mini-circle (MC) system to deliver miR-206 specifically to hepatocytes (designated as MC-miR-206). A single intravenous injection of MC-miR-206 maintained high levels of miR-206 in the liver for at least two weeks, thereby maintaining suppression of hepatic DNL, cholesterol synthesis, and gluconeogenesis. MC-miR-206 significantly reduced DNA damage, endoplasmic reticulum and oxidative stress, and hepatic toxicity. Therapeutically, both MC-miR-206 and statins significantly reduced total serum cholesterol and triglycerides as well as LDL cholesterol and VLDL cholesterol in mice maintained on the normal chow and high-fat high-cholesterol diet. MC-miR-206 reduced liver weight, hepatic triglycerides and cholesterol, and blood glucose, while statins slightly increased hepatic cholesterol and blood glucose and failed to affect levels of liver weight and hepatic triglycerides. Mechanistically, miR-206 alleviated hypercholesterolemia by inhibiting hepatic cholesterol synthesis, while statins increased HMGCR activity, hepatic cholesterol synthesis, and fecal-neutral steroid excretion. MiR-206 facilitates the regression of hypercholesterolemia, hypertriglyceridemia, hyperglycemia, and hepatosteatosis. MiR-206 outperforms statins by reducing hyperglycemia, hepatic cholesterol levels, and hepatic toxicity.

The Brazilian Toxoplasma gondii strain BRI caused greater inflammation and impairment in anxiogenic behavior in mice, which was reverted by rosuvastatin treatment

This study aimed to investigate the effect of rosuvastatin treatment on anxiety-related behavior and short- and long-term memory impairment in mice infected with acute RH and BRI strains of Toxoplasma gondii. Balb/C mice were infected intraperitoneally and after 2 h, oral treatment with rosuvastatin (40 mg/kg/day) was initiated for 4 days. Behaviors related to anxiety and locomotion were evaluated in the open field (OF), and short- and long-term memory through the novel object recognition test (NOR). At the end of the experiments, peritoneal fluid, brain, liver, and lung were collected for T. gondii DNA quantification and histopathological analysis. Infection with BRI strain reduced the dwell time and central locomotion in the OF (p < 0.05), indicating anxiogenic type behavior, while treatment with rosuvastatin reversed this response (p < 0.05). RH strain infection did not alter any behavior in the OF (p > 0.05) and both strains impaired short- and long-term memory (NOR test), but with no significant treatment effect (p > 0.05). The BRI strain was shown to be more damaging in relation to anxiogenic type behavior when compared to the RH strain (p < 0.05), whereas rosuvastatin reduced this damaging effect in BRI. The treatment reduced the parasite load in the peritoneal lavage, liver, and lung of animals infected with both acute strains; however, it significantly (p < 0.05) attenuated the inflammatory process only in BRI-infected and treated animals, showing that non-archetypal genotypes are more damaging in rodents. This suggests that rosuvastatin may be a drug with great therapeutic potential against T. gondii mainly to reduce damage from virulent strains.

Effectiveness of One-Year Pemafibrate Therapy on Non-Alcoholic Fatty Liver Disease Refractory to Long-Term Sodium Glucose Cotransporter-2 Inhibitor Therapy: A Pilot Study

Background: Both pemafibrate and sodium glucose cotransporter-2 (SGLT2) inhibitor can decrease serum transaminase levels in patients with non-alcoholic fatty liver disease (NAFLD) complicated with dyslipidemia and type 2 diabetes mellitus (T2DM), respectively. However, the effectiveness of combined therapy has been rarely reported. Methods: This is a two-center retrospective observational study. NAFLD patients complicated with T2DM treated with pemafibrate for >1 year were included, in whom prior treatment with SGLT2 inhibitor > 1 year failed to normalize serum alanine aminotransferase (ALT) levels. Hepatic inflammation, function, and fibrosis were assessed by ALT, albumin-bilirubin (ALBI) score, and Mac-2 binding protein glycosylation isomer (M2BPGi) levels, respectively. Results: Seven patients were included. The median duration of prior treatment with SGLT2 inhibitors was 2.3 years. During the one year before starting pemafibrate therapy, the therapy did not significantly change hepatic enzymes. All patients received pemafibrate 0.1 mg twice daily without dose escalations. During one year of pemafibrate therapy, triglyceride, aspartate aminotransferase, ALT, γ-glutamyl transpeptidase, ALBI score, and M2BPGi levels significantly improved (p < 0.05), although weight or hemoglobin A1c did not significantly change. Conclusions: One year of pemafibrate therapy improves markers of hepatic inflammation, function, and fibrosis in NAFLD patients in whom long-term SGLT2 inhibitor therapy failed to normalize serum ALT.

Rosuvastatin revert memory impairment and anxiogenic-like effect in mice infected with the chronic ME-49 strain of Toxoplasma gondii

The aim of this study was to investigate the effect of rosuvastatin treatment on memory impairment, and anxiogenic-like effects in mice chronically infected with Toxoplasma gondii. For this, Balb/c mice were infected orally with chronic ME-49 strain of Toxoplasma gondii. Oral treatment with rosuvastatin (40mg/kg/day) started on the 51^st day post-infection and was performed daily for 21 days. After completion of treatment, anxiety-like effects and locomotion were investigated in the open field (OF) test, whereas novel object recognition (NOR) test was used for evaluation of short- and long-term memory. At the end of the experiments, the brain was collected for Toxoplasma gondii DNA quantification and histopathological analysis. Infection with ME-49 strain decreased the time spent in the center of OF, indicating an anxiogenic effect, without affecting total and peripheral locomotion. Rosuvastatin treatment inhibited the change in the center time. Besides, pharmacological treatment increased total and central locomotion in both non-infected and infected animals. Infection also impaired both short- and long-term memory in the NOR test, and these effects were reverted by rosuvastatin treatment. In addition to effects in behavioral changes, rosuvastatin also reduced parasite load in the brain and attenuated signs of brain inflammation such as perivascular cuffs, inflammatory cell infiltration and tissue damage. These findings indicate for the first time the efficacy of rosuvastatin in treatment of memory impairment and anxiogenic effect evoked by infection with Toxoplasma gondii. These effects might be mediated by reduced cyst load, which in turn decrease inflammation and damage in the brain.

Therapeutic effects of açaí seed extract on hepatic steatosis in high-fat diet-induced obesity in male mice: a comparative effect with rosuvastatin

OBJECTIVES

Obesity is considered a risk factor for the development of non-alcoholic fatty liver disease (NAFLD). The hydroalcoholic extract obtained from the açai seed (ASE), rich in proanthocyanidins, has been shown a potential body weight regulator with antioxidant properties. This study aimed to investigate the therapeutic effect of ASE in obesity-associated NAFLD and compare it with Rosuvastatin.

METHODS

Male C57BL/6 mice received a high-fat diet or standard diet for 12 weeks. The treatments with ASE (300 mg/kg per day) or rosuvastatin (20 mg/kg per day) began in the eighth week until the 12th week.

KEY FINDINGS

Our data show that the treatments with ASE and rosuvastatin reduced body weight and hyperglycaemia, improved lipid profile and attenuated hepatic steatosis in HFD mice. ASE and Rosuvastatin reduced HMGCoA-Reductase and SREBP-1C and increased ABGC8 and pAMPK expressions in the liver. Additionally, ASE, but not Rosuvastatin, reduced NPC1L1 and increased ABCG5 and PPAR-α expressions. ASE and rosuvastatin increased SIRT-1 expression and antioxidant defence, although only ASE was able to decrease the oxidative damage in hepatic tissue.

CONCLUSIONS

The therapeutic effect of ASE was similar to that of rosuvastatin in reducing dyslipidemia and hepatic steatosis but was better in reducing oxidative damage and hyperglycaemia.

Genetic determinants of obesity heterogeneity in type II diabetes

Background

Although obesity is considered as the main cause of Type II diabetes (T2DM), non-obese individuals may still develop T2DM and obese individuals may not.

Method

The mRNA expression of PI3K/AKT axis from 100 non-obese and obese participants with insulin sensitivity and insulin resistance states were compared in this study toward the understanding of obesity heterogeneity molecular mechanism.

Result

In present study, there was no statistically significant difference in gene expression levels of IRS1 and PTEN between groups, whereas PI3K, AKT2 and GLUT4 genes were expressed at a lower level in obese diabetic group compared to other groups and were statistically significant. PDK1 gene was expressed at a higher level in non-obese diabetic group compared to obese diabetic and non-obese non-diabetics groups. No statistically significant difference was identified in gene expression pattern of PI3K/AKT pathway between obese non-diabetics and non-obese non-diabetics.

Conclusion

The components of PI3K/AKT pathway which is related to the fasting state, showed reduced expression in obese diabetic group due to the chronic over-nutrition which may induced insensitivity and reduced gene expression. The pathogenesis of insulin resistance in the absence of obesity in non-obese diabetic group could be due to disturbance in another pathway related to the non-fasting state like gluconeogenesis. Therefore, the molecular mechanism of insulin signalling in non-obese diabetic individuals is different from obese diabetics which more investigations are required to study insulin signalling pathways in greater depth, in order to assess nutritional factors, contribute to insulin resistance in obese diabetic and non-obese diabetic individuals.

Rosuvastatin reduced brain parasite burden in a chronic toxoplasmosis in vivo model and influenced the neuropathological pattern of ME-49 strain

This study evaluated the effects of rosuvastatin in vivo on toxoplasmosis chronic infection. Thirty-five Swiss mice were orally infected (ME-49 strain). After 50 days, the mice were separated into five groups: GI - non-infected, GII - infected, GIII - infected and treated with pyrimethamine and sulfadiazine (12.5 + 50 mg kg-1 body weight day-1), GIV and GV - infected and treated with rosuvastatin 10 and 40 mg kg-1 body weight day-1, respectively. After 21 days, we collected blood, liver, lungs, femoral biceps and brain were removed for Toxoplasma gondii DNA quantification by qPCR and histopathological analysis. GIV and GV did not present premature death or clinical changes, and the hepatic enzyme levels were lower compared to GI. Toxoplasma gondii DNA was detected mainly in brain and muscle, but the parasite load was significantly lower in GV compared to GII brains (P < 0.05). Histopathological changes were observed in brains, with T. gondii cysts as well as an inflammatory condition, including necrosis areas in GII and GIII. These data confirm active infection with tissue injury. This inflammatory condition was attenuated in the groups treated with rosuvastatin, especially R40 (GV). Our findings demonstrated the in vivo action of rosuvastatin in reducing cerebral parasitic load and indicate that this drug may interfere in chronic toxoplasmosis.

Rosuvastatin improves olanzapine's effects on behavioral impairment and hippocampal, hepatic and metabolic damages in isolated reared male rats

BACKGROUND & AIM

Schizophrenia is a chronic, disabling neurological illness. This study investigated the effect of rosuvastatin (RSU) addition to the antipsychotic drug: olanzapine (OLZ) in treatment of post-weaning isolation rearing (IR) damaging effect and assessed behavioral impairment, metabolic and hepatic abnormalities, oxidative stress, and inflammatory markers.

METHODS

Treatment with OLZ (6 mg/kg, P.O.) and/or RSU (10 mg/kg, I.P.) have been started 6 weeks after isolation. We assessed behavioral tests, serum cortisol level, and hippocampal content of neurotransmitters. In addition, we assessed histopathology, inflammatory and oxidative stress markers of hippocampus, liver and adipose tissue RESULTS: Treatment of IR animals with OLZ, and/or RSU significantly counteracted the changes in hippocampus, liver and adipose tissue induced by post-weaning IR. Co-treatment of IR rats with both OLZ and RSU showed additive effects in some areas like improving both tumor necrosis factor alpha (TNFα) in both hippocampus and liver, histopathology of liver, oxidative stress markers of adipose tissue, β₃ adrenergic receptors (ADRβ₃), serum cortisol and total cholesterol. In addition, RSU alone alleviated the damage of IR rats by the same efficacy as OLZ with more benefit in cognition and exploration.

CONCLUSION

post-weaning IR as a model has behavioral, hippocampal, hepatic and marked metabolic changes more relevant to schizophrenia than drug-induced models. These effects were ameliorated by RSU and/or OLZ that are explained by their antioxidant, anti-inflammatory, anti-stress and anti-hyperlipidemic properties. Interestingly, co-treatment with both drugs showed a better effect.

Rosuvastatin Reduces Aortic Sinus and Coronary Artery Atherosclerosis in SR-B1 (Scavenger Receptor Class B Type 1)/ApoE (Apolipoprotein E) Double Knockout Mice Independently of Plasma Cholesterol Lowering

Supplemental Digital Content is available in the text.

Objective—

Rosuvastatin has been widely used in the primary and secondary prevention of coronary heart disease. However, its antiatherosclerotic properties have not been tested in a mouse model that could mimic human coronary heart disease. The present study was designed to test the effects of rosuvastatin on coronary artery atherosclerosis and myocardial fibrosis in SR-B1 (scavenger receptor class B type 1) and apoE (apolipoprotein E) double knockout mice.

Approach and Results—

Three-week-old SR-B1^−/−/apoE^−/− mice were injected daily with 10 mg/kg of rosuvastatin for 2 weeks. Compared with saline-treated mice, rosuvastatin-treated mice showed increased levels of hepatic PCSK9 (proprotein convertase subtilisin/kexin type-9) and LDLR (low-density lipoprotein receptor) message, increased plasma PCSK9 protein but decreased levels of hepatic LDLR protein and increased plasma total cholesterol associated with apoB (apolipoprotein B) 48-containing lipoproteins. In spite of this, rosuvastatin treatment was associated with decreased atherosclerosis in both the aortic sinus and coronary arteries and reduced platelet accumulation in atherosclerotic coronary arteries. Cardiac fibrosis and cardiomegaly were also attenuated in rosuvastatin-treated SR-B1^−/−/apoE^−/− mice. Two-week treatment with rosuvastatin resulted in significant decreases in markers of oxidized phospholipids in atherosclerotic plaques. In vitro analysis showed that incubation of bone marrow-derived macrophages with rosuvastatin substantially downregulated cluster of differentiation (CD)36 and inhibited oxidized LDL-induced foam cell formation.

Conclusions—

Rosuvastatin protected SR-B1^−/−/apoE^−/− mice against atherosclerosis and platelet accumulation in coronary arteries and attenuated myocardial fibrosis and cardiomegaly, despite increased plasma total cholesterol. The ability of rosuvastatin to reduce oxidized phospholipids in atherosclerotic plaques and inhibit macrophage foam cell formation may have contributed to this protection.

Molecular mechanism of hepatic steatosis: pathophysiological role of autophagy

Steatosis is an early characteristic in the pathogenesis of fatty liver disease (FLD). Mechanisms of hepatic steatosis are aetiology-dependent. Activation of autophagy in liver ameliorates hepatic steatosis. A modulation of hepatic autophagy affects the degree of hepatocyte steatosis and the progression of FLD as demonstrated by pre-clinical models and clinical trials. This review summarises recent advances on pathophysiological roles of autophagy in hepatic lipid metabolism. A comprehensive regulation of autophagic networks holds promise for the improvement of hepatic steatosis. Autophagic signalling pathway may be a novel therapeutic target against FLD.

HIGHLIGHTS

• Hepatic steatosis is a pathological condition wherein vacuoles of triglyceride (TG) fat are overaccumulated in liver because of abnormal metabolism of lipids. • Hepatic autophagy regulates lipid metabolism as demonstrated by macrolipophagy in response to starvation and hepatic overabundance of TG in obesity. • Autophagic signals are closely associated with apoptotic pathways. There is distinctive relationship between hepatic autophagy and apoptosis, which affects the progression of fatty liver. • Regulation of autophagic process can be a novel therapeutic strategy for fatty liver disease.

Statins increase hepatic cholesterol synthesis and stimulate fecal cholesterol elimination in mice

Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins reduce plasma cholesterol levels, but whether this is actually caused by inhibition of de novo cholesterol synthesis has not been clearly established. Using three different statins, we investigated the effects on cholesterol metabolism in mice in detail. Surprisingly, direct measurement of whole body cholesterol synthesis revealed that cholesterol synthesis was robustly increased in statin-treated mice. Measurement of organ-specific cholesterol synthesis demonstrated that the liver is predominantly responsible for the increase in cholesterol synthesis. Excess synthesized cholesterol did not accumulate in the plasma, as plasma cholesterol decreased. However, statin treatment led to an increase in cholesterol removal via the feces. Interestingly, enhanced cholesterol excretion in response to rosuvastatin and lovastatin treatment was mainly mediated via biliary cholesterol secretion, whereas atorvastatin mainly stimulated cholesterol removal via the transintestinal cholesterol excretion pathway. Moreover, we show that plasma cholesterol precursor levels do not reflect cholesterol synthesis rates during statin treatment in mice. In conclusion, cholesterol synthesis is paradoxically increased upon statin treatment in mice. However, statins potently stimulate the excretion of cholesterol from the body, which sheds new light on possible mechanisms underlying the cholesterol-lowering effects of statins.

Treatment of nonalcoholic fatty liver disease: Where do we stand? an overview

Nonalcoholic fatty liver disease (NAFLD) is currently the most common liver disease worldwide, the prevalence of which had progressively increased over the past 10 years where other liver diseases remained at the same prevalence rates or are expected to decrease as in the case of hepatitis C virus (HCV). The treatment of NAFLD is of prime concern to health care professionals and patients due to the significant mortality and morbidity it implies; the problem is further escalated by the fact that standard of care medications targeting NAFLD remain experimental and without evidence base. Treatment nowadays is focused on lifestyle modification and managing the comorbid associated diseases, with a possible role for some hepatic protective agents. This review presents all the medications that had been proposed and used for the treatment of NAFLD with or without scientific rationale and includes agents for weight loss, insulin sensitizers, drugs that reduce blood lipids, glucagon-mimetics, drugs that may reduce fibrosis, angiotensin receptor blockers, and medicines believed to reduce endoplasmic reticular stress such as vitamin E, ursodeoxycholic acid, and S-adenosyl methionine. A quick review of the newer agents that proved to be promising such as obeticholic acid and GFT505 and the medicines that are still in the pipeline is also presented.

Essential phospholipids as a supportive adjunct in the management of patients with NAFLD

BACKGROUND AND STUDY AIMS

Treatment of nonalcoholic fatty liver (NAFLD) is important because NAFLD patients have a 1.7-fold increase in standardised age and gender matched mortality. Currently treatment is based on life style modification and managing comorbid associating disease. Other medications remain experimental. Essential phospholipid (EPL) is a nutrient for the liver, helping to maintain vitality of cell membranes where the vast majority of liver activities are regulated. We performed a randomised open label study to evaluate EPL as an adjuvant nutrient to the treatment of primary NAFLD or NAFLD with comorbid disease.

PATIENTS AND METHOD

Three groups of NAFLD patients were recruited: lone (n=113), diabetes mellitus type 2 (n=107) and mixed hyperlipidaemia (n=104). Diagnosis was established by excluding other chronic liver diseases. A standard diet and physical activity plan were advised to all patients. 1800mg of EPL a day was given for 24weeks, followed by 900mg for 48weeks.

RESULTS

Essential phospholipid EPL led to a significant improvement of symptoms and a mean reduction of ALT of 50.8IU and AST of 46.1IU per patient (p<0.01). Abdominal ultrasonography indicated normalisation in 4.6% and a shift from grade II to grade I in 24% of patients. Liver stiffness measurement indicated an improvement in 21.1%, with a mean reduction in the LSM of 3.1K Pascal/patient. Reducing the dosage after six months led to a limited relapse in 43.8-63.2% of patients, for lone and NAFLD with co-morbid conditions.

CONCLUSION

Essential phospholipid (EPL) as a nutritional supplement resulted in a significant improvement in clinical parameters and transaminases for all NAFLD patients. Ultrasound and LSM revealed modest improvement. There is a need for uninterrupted maintenance to avoid relapse.

Resolution of non-alcoholic steatohepatitis by rosuvastatin monotherapy in patients with metabolic syndrome

AIM: To investigate the effect of rosuvastatin monotherapy on non-alcoholic steatohepatitis (NASH). At present there is no effective treatment for non-alcoholic fatty liver disease or its advanced form NASH.

METHODS: This prospective study included 20 biopsy proven patients with NASH, metabolic syndrome (MetS) and dyslipidaemia. Biochemical parameters of the blood of the patients and an ultrasonography of the liver were performed at baseline. Then patients received lifestyle advice and were treated for a 12 mo period with rosuvastatin (10 mg/d) monotherapy. Patients were re-evaluated during the study at 3 mo intervals, during which biochemical parameters of the blood were measured including liver enzymes. A repeat biopsy and ultrasonography of the liver were performed at the end of the study in all 20 patients. Changes in liver enzymes, fasting plasma glucose, serum creatinine, serum uric acid (SUA), high sensitivity C reactive protein (hsCRP) and lipid profile were assessed every 3 mo. The primary endpoint was the resolution of NASH and the secondary endpoints were the changes in liver enzyme and lipid values.

RESULTS: The repeat liver biopsy and ultrasonography showed complete resolution of NASH in 19 patients, while the 20^th, which had no improvement but no deterioration either, developed arterial hypertension and substantial rise in triglyceride levels during the study, probably due to changes in lifestyle including alcohol abuse. Serum alanine transaminase, aspartate transaminase, and γ-glutamyl transpeptidase were normalised by the 3^rd treatment month (ANOVA P < 0.001), while alkaline phosphatase activities by the 6^th treatment month (ANOVA, P = 0.01). Fasting plasma glucose and glycated haemoglobin were significantly reduced (P < 0.001). Lipid values were normalised by the 3^rd treatment month. No patient had MetS by the 9^th treatment month. Body mass index and waist circumference remained unchanged during the study. Thus, changes in liver pathology and function should be attributed solely to rosuvastatin treatment. A limitation of the study is the absence of a control group.

CONCLUSION: These findings suggest that rosuvastatin monotherapy could ameliorate biopsy proven NASH and resolve MetS within 12 mo. These effects and the reduction of fasting plasma glucose and SUA levels may reduce the risk of vascular and liver morbidity and mortality in NASH patients. These findings need confirmation in larger studies.

Effects of rosuvastatin and/or β-carotene on non-alcoholic fatty liver in rats

The prevalence of non-alcoholic fatty liver disease (NAFLD) has markedly increased, especially in patients exhibit one or more features of the metabolic syndrome. This study investigates the effect of rosuvastatin (RSV) and/or β-carotene (βC) in NAFLD-induced rats. Rats were classified into nine groups; normal (I), NAFLD-induced with high-fat diet (HFD; II), NAFLD switched to regular diet (RD; III), NAFLD-HFD or NAFLD-RD treated with RSV (IV, V), βC (VI, VII) or both RSV+βC (VIII, IX), respectively. After four weeks, rats were sacrificed to obtain serum samples and liver tissues. Liver histology, lipid profile, liver oxidative stress markers, and adipocytokines were measured. Liver sections of rats with NAFLD-HFD revealed steatosis, lose of hepatic architecture, inflammation and hepatocyte vacuolation with high percentage of cell fibrosis. Serum levels of ALT, AST, ALP, gamma glutamyl transferase (GGT) and lipid profile (triglycerides, cholesterol, LDL and VLDL) were significantly increased (P<0.05) compared with normal. Also, hepatic malondialdehyde level and serum leptin, tumor necrosis factor-alpha (TNF-α) and transforming growth factor-β1 (TGF-β1) were increased. Meanwhile, superoxide dismutase (SOD) activity, GSH content in liver, serum HDL and adiponectin were decreased (P<0.05) vs normal. These changes were observed to a lesser extent in NAFLD-RD group. Administration of RSV or/and βC almost improved all previously mentioned parameters. Moreover, hepatic steatosis was decreased and inflammation was markedly ameliorated with reduction of TNF-α and TGF-β. These results were more pronounced in the groups VIII and IX vs each drug alone. In conclusion RSV and βC could be beneficial for the treatment and prevention of NAFLD. Combined RSV with βC is more effective than RSV alone.

PTEN upregulation may explain the development of insulin resistance and type 2 diabetes with high dose statins

PURPOSE

Statins increase the incidence of new onset diabetes. Prolonged statin therapy upregulates PTEN expression. PTEN levels are also elevated in diabetic animals. Activation of protein kinase A by cAMP decreases PTEN expression. We assessed whether prolonged treatment with rosuvastatin (ROS) induces glucose intolerance by upregulating Phosphatase and Tensin Homologue on Chromosome 10 (PTEN) in mice receiving normal (ND) or Western Diet (WD) and whether concomitant treatment with cilostazol (CIL, a phosphodiesterase-3 inhibitor) attenuates the effects.

METHODS

PTEN(loxp/cre) or PTEN(+/-) mice received ND or WD without or with ROS (10 mg/kg/day). Wild-type mice received ND or WD without or with ROS, CIL (10 mg/kg/day), or ROS+CIL for 30 days. Fasting insulin and glucose tolerance test were measured as well as PTEN and P-AKT levels in skeletal muscle.

RESULTS

Serum glucose after intraperitoneal injection of glucose was higher in PTEN(loxp/cre) mice receiving WD or ROS and especially WD+ROS. Levels were lower in PTEN(+/-) mice compared to PTEN(loxp/cre) in each treatment group. CIL decreased glucose levels in mice receiving WD, ROS and their combination. Insulin levels were higher in the WD+ROS group. CIL decreased insulin in mice receiving WD+ROS. WD, ROS and especially their combination increased PTEN and decreased P-AKT levels. CIL attenuated the effect of WD, ROS and their combination.

CONCLUSIONS

Long-term ROS can induce diabetes by upregulating PTEN. CIL attenuates these changes. Partial knockdown of PTEN also ameliorates ROS-induced insulin resistance. Further studies are needed to assess the effects of increasing cAMP levels to prevent the induction of diabetes by statins.

Peroxisome proliferator-activated receptors as targets to treat non-alcoholic fatty liver disease

Lately, the world has faced tremendous progress in the understanding of non-alcoholic fatty liver disease (NAFLD) pathogenesis due to rising obesity rates. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that modulate the expression of genes involved in lipid metabolism, energy homeostasis and inflammation, being altered in diet-induced obesity. Experimental evidences show that PPAR-alpha is the master regulator of hepatic beta-oxidation (mitochondrial and peroxisomal) and microsomal omega-oxidation, being markedly decreased by high-fat (HF) intake. PPAR-beta/delta is crucial to the regulation of forkhead box-containing protein O subfamily-1 expression and, hence, the modulation of enzymes that trigger hepatic gluconeogenesis. In addition, PPAR-beta/delta can activate hepatic stellate cells aiming to the hepatic recovery from chronic insult. On the contrary, PPAR-gamma upregulation by HF diets maximizes NAFLD through the induction of lipogenic factors, which are implicated in the fatty acid synthesis. Excessive dietary sugars also upregulate PPAR-gamma, triggering de novo lipogenesis and the consequent lipid droplets deposition within hepatocytes. Targeting PPARs to treat NAFLD seems a fruitful approach as PPAR-alpha agonist elicits expressive decrease in hepatic steatosis by increasing mitochondrial beta-oxidation, besides reduced lipogenesis. PPAR-beta/delta ameliorates hepatic insulin resistance by decreasing hepatic gluconeogenesis at postprandial stage. Total PPAR-gamma activation can exert noxious effects by stimulating hepatic lipogenesis. However, partial PPAR-gamma activation leads to benefits, mainly mediated by increased adiponectin expression and decreased insulin resistance. Further studies are necessary aiming at translational approaches useful to treat NAFLD in humans worldwide by targeting PPARs.