Atorvastatin but Not Pravastatin Impairs Mitochondrial Function in Human Pancreatic Islets and Rat β-Cells. Direct Effect of Oxidative Stress

Short-Term Statin Treatment Reduces, and Long-Term Statin Treatment Abolishes, Chronic Vascular Injury by Radiation Therapy

BACKGROUND

The incidental use of statins during radiation therapy has been associated with a reduced long-term risk of developing atherosclerotic cardiovascular disease. We examined whether irradiation causes chronic vascular injury and whether short-term administration of statins during and after irradiation is sufficient to prevent chronic injury compared with long-term administration.

METHODS AND RESULTS

C57Bl/6 mice were pretreated with pravastatin for 72 hours and then exposed to 12 Gy X-ray head-and-neck irradiation. Pravastatin was then administered either for an additional 24 hours or for 1 year. Carotid arteries were tested for vascular reactivity, altered gene expression, and collagen deposition 1 year after irradiation. Treatment with pravastatin for 24 hours after irradiation reduced the loss of endothelium-dependent vasorelaxation and protected against enhanced vasoconstriction. Expression of markers associated with inflammation (NFκB p65 [phospho-nuclear factor kappa B p65] and TNF-α [tumor necrosis factor alpha]) and with oxidative stress (NADPH oxidases 2 and 4) were lowered and subunits of the voltage and Ca2+ activated K+ BK channel (potassium calcium-activated channel subfamily M alpha 1 and potassium calcium-activated channel subfamily M regulatory beta subunit 1) in the carotid artery were modulated. Treatment with pravastatin for 1 year after irradiation completely reversed irradiation-induced changes.

CONCLUSIONS

Short-term administration of pravastatin is sufficient to reduce chronic vascular injury at 1 year after irradiation. Long-term administration eliminates the effects of irradiation. These findings suggest that a prospective treatment strategy involving statins could be effective in patients undergoing radiation therapy. The optimal duration of treatment in humans has yet to be determined.

Hesperidin, vanillic acid, and sinapic acid attenuate atorvastatin-induced mitochondrial dysfunction via inhibition of mitochondrial swelling and maintenance of mitochondrial function in pancreas isolated mitochondria

It has been reported that lipophilic statins such as atorvastatin can more readily penetrate into β-cells and reach the mitochondria, resulting in mitochondrial dysfunction, oxidative stress, decrease in insulin release. Many studies have shown that natural products can protect mitochondrial dysfunction induced by drug in different tissue. We aimed to explore mitochondrial protection potency of hesperidin, vanillic acid, and sinapic acid as natural compounds against mitochondrial dysfunction induced by atorvastatin in pancreas isolated mitochondria. Mitochondria were isolated form rat pancreas and directly treated with toxic concentration of atorvastatin (500 µM) in presence of various concentrations hesperidin, vanillic acid, and sinapic acid (1, 10, and 100 µM) separately. Mitochondrial toxicity parameters such as the reactive oxygen species (ROS) formation, succinate dehydrogenases (SDH) activity, mitochondrial swelling, depletion of glutathione (GSH), mitochondrial membrane potential (MMP) collapse, and malondialdehyde (MDA) production were measured. Our findings demonstrated that atorvastatin directly induced mitochondrial toxicity at concentration of 500 μM and higher in pancreatic mitochondria. Except MDA, atorvastatin caused significantly reduction in SDH activity, mitochondrial swelling, ROS formation, depletion of GSH, and collapse of MMP. While, our data showed that all three protective compounds at low concentrations ameliorated atorvastatin-induced mitochondrial dysfunction with the increase of SDH activity, improvement of mitochondrial swelling, MMP collapse and mitochondrial GSH, and reduction of ROS formation. We can conclude that hesperidin, vanillic acid, and sinapic acid can directly reverse the toxic of atorvastatin in rat pancreas isolated mitochondria, which may be beneficial for protection against diabetogenic-induced mitochondrial dysfunction in pancreatic β-cells.

Fluvastatin-induced myofibrillar damage is associated with elevated ROS, and impaired fatty acid oxidation, and is preceded by mitochondrial morphological changes

Previously, we showed that fluvastatin treatment induces myofibrillar damage and mitochondrial phenotypes in the skeletal muscles of Drosophila. However, the sequential occurrence of mitochondrial phenotypes and myofibril damage remains elusive. To address this, we treated flies with fluvastatin for two and five days and examined their thorax flight muscles using confocal microscopy. In the two-day fluvastatin group, compared to the control, thorax flight muscles exhibited mitochondrial morphological changes, including fragmentation, rounding up and reduced content, while myofibrils remained organized in parallel. In the five-day fluvastatin treatment, not only did mitochondrial morphological changes become more pronounced, but myofibrils became severely disorganized with significantly increased thickness and spacing, along with myofilament abnormalities, suggesting myofibril damage. These findings suggest that fluvastatin-induced mitochondrial changes precede myofibril damage. Moreover, in the five-day fluvastatin group, the mitochondria demonstrated elevated H2O2 and impaired fatty acid oxidation compared to the control group, indicating potential mitochondrial dysfunction. Surprisingly, knocking down Hmgcr (Drosophila homolog of HMGCR) showed normal mitochondrial respiration in all parameters compared to controls or five-day fluvastatin treatment, which suggests that fluvastatin-induced mitochondrial dysfunction might be independent of Hmgcr inhibition. These results provide insights into the sequential occurrence of mitochondria and myofibril damage in statin-induced myopathy for future studies.

Differential effects of OATP2B1 on statin accumulation and toxicity in a beta cell model

An increased risk of new-onset diabetes mellitus has been recently reported for statin therapy, and experimental studies have shown reduced glucose-stimulated insulin secretion (GSIS) and mitochondrial dysfunction in beta cells with effects differing among agents. Organic anion transporting polypeptide (OATP) 2B1 contributes to hepatic uptake of rosuvastatin, atorvastatin and pravastatin, three known substrates. Since OATP2B1 is present in beta cells of the human pancreas, we investigated if OATP2B1 facilitates the local accumulation of statins in a rat beta cell model INS-1 832/13 (INS-1) thereby amplifying statin-induced toxicity. OATP2B1 overexpression in INS-1 cells via adenoviral transduction showed 2.5-, 1.8- and 1.4-fold higher cellular retention of rosuvastatin, atorvastatin and pravastatin, respectively, relative to LacZ control, while absolute intracellular concentration was about twice as high for the lipophilic atorvastatin compared to the more hydrophilic rosuvastatin and pravastatin. After 24 h statin treatment at high concentrations, OATP2B1 enhanced statin toxicity involving activation of intrinsic apoptosis (caspase 3/7 activation) and mitochondrial dysfunction (NADH dehydrogenase activity) following rosuvastatin and atorvastatin, which was partly reversed by isoprenoids. OATP2B1 had no effect on statin-induced reduction in GSIS, mitochondrial electron transport chain complex expression or caspase 9 activation. We confirmed a dose-dependent reduction in insulin secretion by rosuvastatin and atorvastatin in native INS-1 with a modest change in cellular ATP. Collectively, our results indicate a role of OATP2B1, which is abundant in human beta cells, in statin accumulation and statin-induced toxicity but not insulin secretion of rosuvastatin and atorvastatin in INS-1 cells.

Mitochondrial Dysfunction, Oxidative Stress, and Inter-Organ Miscommunications in T2D Progression

Type 2 diabetes (T2D) is a heterogenous disease, and conventionally, peripheral insulin resistance (IR) was thought to precede islet β-cell dysfunction, promoting progression from prediabetes to T2D. New evidence suggests that T2D-lean individuals experience early β-cell dysfunction without significant IR. Regardless of the primary event (i.e., IR vs. β-cell dysfunction) that contributes to dysglycemia, significant early-onset oxidative damage and mitochondrial dysfunction in multiple metabolic tissues may be a driver of T2D onset and progression. Oxidative stress, defined as the generation of reactive oxygen species (ROS), is mediated by hyperglycemia alone or in combination with lipids. Physiological oxidative stress promotes inter-tissue communication, while pathological oxidative stress promotes inter-tissue mis-communication, and new evidence suggests that this is mediated via extracellular vesicles (EVs), including mitochondria containing EVs. Under metabolic-related stress conditions, EV-mediated cross-talk between β-cells and skeletal muscle likely trigger mitochondrial anomalies leading to prediabetes and T2D. This article reviews the underlying molecular mechanisms in ROS-related pathogenesis of prediabetes, including mitophagy and mitochondrial dynamics due to oxidative stress. Further, this review will describe the potential of various therapeutic avenues for attenuating oxidative damage, reversing prediabetes and preventing progression to T2D.

Sesamol combats diabetogenic effects of atorvastatin through GLUT-4 expression and improved pancreatic viability

Statin-associated diabetes (SAD) is an issue that has come to light after a series of recent clinical trials that has led to the issue of a black box warning for statins by the US FDA. However, the benefit of statin outweighs its risk. Nevertheless, experiments have been conducted to identify the mechanism by which statins aggravate the risk of diabetes only in a select population who bear the risk factors of obesity, sedentary lifestyle, hypertension, and other associated risk factors of lifestyle disorders. In this study, the possibility of utilization of a phyto-molecule, sesamol, for its ability to combat statin-associated diabetes using atorvastatin as the agent of choice has been explored. MMP assay and western blot was conducted to investigate the effects of atorvastatin on apoptotic cascade with sesamol as a protective agent was conducted in MIN-6 cells. Effect of the combination was tested in L6 cells with 2-NBDG uptake assay and as well as western blot for GLUT-4. A diet-induced hypercholesterolemia model was developed in an in vivo model animals and treated with atorvastatin and sesamol with histopathological analysis being carried out to evaluate the apoptotic markers and GLUT-4 presence. It was found that sesamol can combat pancreatic beta cell apoptosis via the internal apoptotic pathway activated by atorvastatin. With regards to muscle cells, sesamol could improve the GLUT-4 vesical production, but not improve glucose uptake which is inhibited by atorvastatin. These findings are further confirmed by animal studies. These findings indicate that sesamol can serve as a prototype molecule for further development and investigation of similar compounds to tackle SAD.

Cholesterol Paradox in Older People with Type 2 Diabetes Mellitus Regardless of Lipid-Lowering Drug Use: A Cross-Sectional Cohort Study

Lipid-lowering drugs (LLDs) have protective effects against coronary artery disease (CAD) and cerebrovascular disease (CVD); however, a paradoxical association with cholesterol has been identified in several diseases, such as diabetes, dementia, and atrial fibrillation. We aimed to analyze the association between LLDs and cholesterol levels in older adults with type 2 diabetes mellitus (T2DM). This cross-sectional study enrolled consecutive patients aged ≥50 years from three centers in Taiwan. A multiple logistic regression model was used, and odds ratios (ORs) for different levels of total cholesterol (TC) or low-density-lipoprotein cholesterol (LDL-C) compared with the highest level were adjusted for age, triglyceride level, sex, comorbidities, and medications. Among the 3688 participants, 572 with and 676 without T2DM used LLDs. After adjusting for age and sex, the non-T2DM group demonstrated better medical conditions, cognition, and daily function than the T2DM group, regardless of LLD use. Compared to the highest TC level (≥240 mg/dL), ORs were significantly increased as TC levels decreased. A similar pattern of T2DM prevalence was observed in LDL-C levels. Older people with T2DM demonstrated low cognitive and daily functions. Significantly reduced TC and LDL levels were associated with a higher T2DM prevalence in older adults regardless of LLD use. T2DM was associated with impaired cognitive and daily functioning. A higher prevalence of T2DM in older people with low cholesterol levels raises doubt surrounding cognition and daily function being jeopardized when the "lower is better" strategy is applied for the secondary prevention of CAD or CVD.

Mechanisms by which statins protect endothelial cells from radiation-induced injury in the carotid artery

Background

The incidental use of statins during radiation therapy has been associated with a reduced long-term risk of developing atherosclerotic cardiovascular disease. However, the mechanisms by which statins protect the vasculature from irradiation injury remain poorly understood.

Objectives

Identify the mechanisms by which the hydrophilic and lipophilic statins pravastatin and atorvastatin preserve endothelial function after irradiation.

Methods

Cultured human coronary and umbilical vein endothelial cells irradiated with 4 Gy and mice subjected to 12 Gy head-and-neck irradiation were pretreated with statins and tested for endothelial dysfunction, nitric oxide production, oxidative stress, and various mitochondrial phenotypes at 24 and 240 h after irradiation.

Results

Both pravastatin (hydrophilic) and atorvastatin (lipophilic) were sufficient to prevent the loss of endothelium-dependent relaxation of arteries after head-and-neck irradiation, preserve the production of nitric oxide by endothelial cells, and suppress the cytosolic reactive oxidative stress associated with irradiation. However, only pravastatin inhibited irradiation-induced production of mitochondrial superoxide; damage to the mitochondrial DNA; loss of electron transport chain activity; and expression of inflammatory markers.

Conclusions

Our findings reveal some mechanistic underpinnings of the vasoprotective effects of statins after irradiation. Whereas both pravastatin and atorvastatin can shield from endothelial dysfunction after irradiation, pravastatin additionally suppresses mitochondrial injury and inflammatory responses involving mitochondria. Clinical follow-up studies will be necessary to determine whether hydrophilic statins are more effective than their lipophilic counterparts in reducing the risk of cardiovascular disease in patients undergoing radiation therapy.

Statins Induce Locomotion and Muscular Phenotypes in Drosophila melanogaster That Are Reminiscent of Human Myopathy: Evidence for the Role of the Chloride Channel Inhibition in the Muscular Phenotypes

The underlying mechanisms for statin-induced myopathy (SIM) are still equivocal. In this study, we employ Drosophila melanogaster to dissect possible underlying mechanisms for SIM. We observe that chronic fluvastatin treatment causes reduced general locomotion activity and climbing ability. In addition, transmission microscopy of dissected skeletal muscles of fluvastatin-treated flies reveals strong myofibrillar damage, including increased sarcomere lengths and Z-line streaming, which are reminiscent of myopathy, along with fragmented mitochondria of larger sizes, most of which are round-like shapes. Furthermore, chronic fluvastatin treatment is associated with impaired lipid metabolism and insulin signalling. Mechanistically, knockdown of the statin-target Hmgcr in the skeletal muscles recapitulates fluvastatin-induced mitochondrial phenotypes and lowered general locomotion activity; however, it was not sufficient to alter sarcomere length or elicit myofibrillar damage compared to controls or fluvastatin treatment. Moreover, we found that fluvastatin treatment was associated with reduced expression of the skeletal muscle chloride channel, ClC-a (Drosophila homolog of CLCN1), while selective knockdown of skeletal muscle ClC-a also recapitulated fluvastatin-induced myofibril damage and increased sarcomere lengths. Surprisingly, exercising fluvastatin-treated flies restored ClC-a expression and normalized sarcomere lengths, suggesting that fluvastatin-induced myofibrillar phenotypes could be linked to lowered ClC-a expression. Taken together, these results may indicate the potential role of ClC-a inhibition in statin-associated muscular phenotypes. This study underlines the importance of Drosophila melanogaster as a powerful model system for elucidating the locomotion and muscular phenotypes, promoting a better understanding of the molecular mechanisms underlying SIM.

Oxidative stress and impaired insulin secretion in cystic fibrosis pig pancreas

Cystic fibrosis-related diabetes (CFRD) is one the most common comorbidities in cystic fibrosis (CF). Pancreatic oxidative stress has been postulated in the pathogenesis of CFRD, but no studies have been done to show an association. The main obstacle is the lack of suitable animal models and no immediate availability of pancreas tissue in humans. In the CF porcine model, we found increased pancreatic total glutathione (GSH), glutathione disulfide (GSSG), 3-nitrotyrosine- and 4-hydroxynonenal-modified proteins, and decreased copper zinc superoxide dismutase (CuZnSOD) activity, all indicative of oxidative stress. CF pig pancreas demonstrated increased DHE oxidation (as a surrogate marker of superoxide) in situ compared to non-CF and this was inhibited by a SOD-mimetic (GC4401). Catalase and glutathione peroxidase activities were not different between CF and non-CF pancreas. Isolated CF pig islets had significantly increased DHE oxidation, peroxide production, reduced insulin secretion in response to high glucose and diminished secretory index compared to non-CF islets. Acute treatment with apocynin or an SOD mimetic failed to restore insulin secretion. These results are consistent with the hypothesis that CF pig pancreas is under significant oxidative stress as a result of increased O2 ●- and peroxides combined with reduced antioxidant defenses against reactive oxygen species (ROS). We speculate that insulin secretory defects in CF may be due to oxidative stress.

Baseline plasma IL-18 may predict simvastatin treatment response in patients with ARDS: a secondary analysis of the HARP-2 randomised clinical trial

BACKGROUND

Interleukin (IL)-18 is a marker of inflammasome activation, and high baseline plasma IL-18 is associated with increased mortality in patients with sepsis-induced ARDS. The aim of this analysis was to determine if simvastatin was associated with benefit in patients with ARDS and high plasma IL-18.

METHODS

In this secondary analysis of the HARP-2 study, we compared 28-day mortality and response to simvastatin according to baseline plasma IL-18 using cox proportional hazards analysis. Separately, monocyte-derived macrophages from healthy volunteers were pre-incubated with simvastatin or rosuvastatin before stimulation with ATP and LPS, and the effect on secreted IL-18 and IL-1β compared.

RESULTS

511 patients from HARP-2 had available data. High baseline plasma IL-18 (≥ 800 pg/ml) was associated with increased 28-day mortality (high IL-18 30.6% vs. low IL-18 17.5%; HR 1.89 [95% CI 1.30-2.73]; p = 0.001). Allocation to simvastatin in patients with high baseline plasma IL-18 was associated with a lower probability of 28-day mortality compared with placebo (24.0% vs 36.8%; p = 0.01). Finally, simvastatin, but not rosuvastatin, reduced stimulated macrophage secretion of IL-18 and IL-1β.

CONCLUSION

In patients with high baseline plasma IL-18, simvastatin is associated with a higher probability of survival, and this effect may be due to reduced inflammasome activation. These data suggest that baseline plasma IL-18 may allow a personalised treatment approach by identifying patients with ARDS who could benefit from simvastatin therapy.

Zebrafish: A New Promise to Study the Impact of Metabolic Disorders on the Brain

Zebrafish has become a popular model to study many physiological and pathophysiological processes in humans. In recent years, it has rapidly emerged in the study of metabolic disorders, namely, obesity and diabetes, as the regulatory mechanisms and metabolic pathways of glucose and lipid homeostasis are highly conserved between fish and mammals. Zebrafish is also widely used in the field of neurosciences to study brain plasticity and regenerative mechanisms due to the high maintenance and activity of neural stem cells during adulthood. Recently, a large body of evidence has established that metabolic disorders can alter brain homeostasis, leading to neuro-inflammation and oxidative stress and causing decreased neurogenesis. To date, these pathological metabolic conditions are also risk factors for the development of cognitive dysfunctions and neurodegenerative diseases. In this review, we first aim to describe the main metabolic models established in zebrafish to demonstrate their similarities with their respective mammalian/human counterparts. Then, in the second part, we report the impact of metabolic disorders (obesity and diabetes) on brain homeostasis with a particular focus on the blood-brain barrier, neuro-inflammation, oxidative stress, cognitive functions and brain plasticity. Finally, we propose interesting signaling pathways and regulatory mechanisms to be explored in order to better understand how metabolic disorders can negatively impact neural stem cell activity.

Undertreatment or Overtreatment With Statins: Where Are We?

Statins, in addition to healthy lifestyle interventions, are the cornerstone of lipid-lowering therapy. Other low-density lipoprotein (LDL)-lowering drugs include ezetimibe, bile acid sequestrants, and PCSK9 inhibitors. As new evidence emerges from new clinical trials, therapeutic goals change, leading to renewed clinical guidelines. Nowadays, LDL goals are getting lower, leading to the "lower is better" paradigm in LDL-cholesterol (LDL-C) management. Several observational studies have shown that LDL-C control in real life is suboptimal in both primary and secondary preventions. It is critical to enhance the adherence to guideline recommendations through shared decision-making between clinicians and patients, with patient engagement in selecting interventions based on individual values, preferences, and associated conditions and comorbidities. This narrative review summarizes the evidence regarding the benefits of lipid-lowering drugs in reducing cardiovascular events, the pleiotropic effect of statins, real-world data on overtreatment and undertreatment of lipid-lowering therapies, and the changing LDL-C in targets in the clinical guidelines of dyslipidemias over the years.

Updated Understanding of the Crosstalk Between Glucose/Insulin and Cholesterol Metabolism

Glucose and cholesterol engage in almost all human physiological activities. As the primary energy substance, glucose can be assimilated and converted into diverse essential substances, including cholesterol. Cholesterol is mainly derived from de novo biosynthesis and the intestinal absorption of diets. It is evidenced that glucose/insulin promotes cholesterol biosynthesis and uptake, which have been targeted by several drugs for lipid-lowering, e.g., bempedoic acid, statins, ezetimibe, and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. Inversely, these lipid-lowering drugs may also interfere with glucose metabolism. This review would briefly summarize the mechanisms of glucose/insulin-stimulated cholesterol biosynthesis and uptake, and discuss the effect and mechanisms of lipid-lowering drugs and genetic mutations on glucose homeostasis, aiming to help better understand the intricate relationship between glucose and cholesterol metabolism.

Prescription Drugs and Mitochondrial Metabolism

Mitochondria are central to the physiology and survival of nearly all eukaryotic cells and house diverse metabolic processes including oxidative phosphorylation, reactive oxygen species buffering, metabolite synthesis/exchange, and Ca2+ sequestration. Mitochondria are phenotypically heterogeneous and this variation is essential to the complexity of physiological function among cells, tissues, and organ systems. As a consequence of mitochondrial integration with so many physiological processes, small molecules that modulate mitochondrial metabolism induce complex systemic effects. In the case of many common prescribed drugs, these interactions may contribute to drug therapeutic mechanisms, induce adverse drug reactions, or both. The purpose of this article is to review historical and recent advances in the understanding of the effects of prescription drugs on mitochondrial metabolism. Specific 'modes' of xenobiotic-mitochondria interactions are discussed to provide a set of qualitative models that aid in conceptualizing how the mitochondrial energy transduction system may be affected. Findings of recent in vitro high-throughput screening studies are reviewed, and a few candidate drug classes are chosen for additional brief discussion (i.e. antihyperglycemics, antidepressants, antibiotics, and antihyperlipidemics). Finally, recent improvements in pharmacokinetic models that aid in quantifying systemic effects of drug-mitochondria interactions are briefly considered.

The Intestinal Effect of Atorvastatin: Akkermansia muciniphila and Barrier Function

Studies have shown that the cholesterol-lowering medicine statins alter the gut microbiome, induce chronic metabolic inflammation, and disrupt glycemic homeostasis. In this study, we aimed to investigate whether effects of atorvastatin (Ator) on gut microbiome and metabolic inflammation could be causally correlated. Mice at 8-week age were fed with high-fat diet (HFD) or HFD with Ator (HFD+Ator) for 16 weeks. 16S rRNA sequencing of stool and RNA sequencing of colon tissue were employed to analyze the intestinal alterations that could be induced by Ator. A human colon carcinoma cell line (Caco₂) was used for in vitro experiments on barrier function. Compared to HFD, HFD+Ator induced more weight gain, impaired glucose tolerance, and led to gut microbiota dysbiosis, such as suppressing Akkermansia muciniphila in mice. The expressions of tight junction (TJ) proteins were attenuated in the colon, and the serum LPS-binding-protein (LBP) level was elevated in HFD+Ator mice, so as to transcriptionally activate the intestinal nuclear factor-k-gene binding (NF-κB) signaling pathway. Consistently, Ator impaired the barrier function of Caco₂, and treatment of supernatant of A. Muciniphila culture could decrease the intestinal permeability and recover the attenuated expression of TJ proteins induced by Ator. In conclusion, long-term use of Ator with HFD may alter gut microbiota, induce intestinal barrier dysfunction, and hence promote chronic inflammation that contributes to disrupted glycemic homeostasis.

Divergent effects of HIV reverse transcriptase inhibitors on pancreatic beta-cell function and survival: Potential role of oxidative stress and mitochondrial dysfunction

Antiretroviral therapy (ART), a life-saving treatment strategy in HIV/AIDS, has been implicated in increasing the risk of type 2 diabetes mellitus (T2DM). Direct damaging effects on beta-cell function and survival by either non-nucleoside reverse transcriptase inhibitors (NNRTIs) or nucleoside/tide reverse transcriptase inhibitors (NRTIs) may predispose individuals to developing T2DM or if already type 2 diabetic, to insulin dependency. The aim of this study was to investigate the effects of the NNRTIs efavirenz, rilpivirine and doravirine, and the NRTIs tenofovir disoproxil fumarate and emtricitabine, on beta-cell function and survival while suggesting potential cellular and molecular mechanism(s). Our results show contrasting effects within the NNRTI class as doravirine did not cause damaging effects in the rat insulinoma INS-1E cells while efavirenz and rilpivirine reduced insulin release and cell viability, and induced apoptosis in INS-1E cells. Additionally, efavirenz and rilpivirine increased ROS generation, disrupted Δψm and upregulated the mRNA and protein expression of CHOP and GRP78, key markers of endoplasmic reticulum stress. In silico docking studies predict a possible inhibition of the mitochondrial ATP synthase by rilpivirine. On the contrary, both the NRTIs tenofovir disoproxil fumarate and emtricitabine did not affect GSIS, cell viability and apoptosis/necrosis levels in INS-1E cells. The deleterious effects observed in beta-cells exposed to efavirenz or rilpivirine may be, at least partially, mediated by oxidative stress and mitochondrial toxicity. These findings provide potential mechanism(s) by which efavirenz and rilpivirine may contribute to the pathogenesis of T2DM and the progression of T2DM to insulin dependency in HIV-infected type 2 diabetics.

Autophagy inhibitors increase the susceptibility of KRAS-mutant human colorectal cancer cells to a combined treatment of 2-deoxy-D-glucose and lovastatin

RAS-driven colorectal cancer relies on glucose metabolism to support uncontrolled growth. However, monotherapy with glycolysis inhibitors like 2-deoxy-D-glucose causes limited effectiveness. Recent studies suggest that anti-tumor effects of glycolysis inhibition could be improved by combination treatment with inhibitors of oxidative phosphorylation. In this study we investigated the effect of a combination of 2-deoxy-D-glucose with lovastatin (a known inhibitor of mevalonate pathway and oxidative phosphorylation) on growth of KRAS-mutant human colorectal cancer cell lines HCT116 and LoVo. A combination of lovastatin (>3.75 μM) and 2-deoxy-D-glucose (>1.25 mM) synergistically reduced cell viability, arrested cells in the G2/M phase, and induced apoptosis. The combined treatment also reduced cellular oxygen consumption and extracellular acidification rate, resulting in decreased production of ATP and lower steady-state ATP levels. Energy depletion markedly activated AMPK, inhibited mTOR and RAS signaling pathways, eventually inducing autophagy, the cellular pro-survival process under metabolic stress, whereas inhibition of autophagy by chloroquine (6.25 μM) enhanced the cytotoxic effect of the combination of lovastatin and 2-deoxy-D-glucose. These in vitro experiment results were reproduced in a nude mouse xenograft model of HCT116 cells. Our findings suggest that concurrently targeting glycolysis, oxidative phosphorylation, and autophagy may be a promising regimen for the management of RAS-driven colorectal cancers.

Impaired HMG-CoA Reductase Activity Caused by Genetic Variants or Statin Exposure: Impact on Human Adipose Tissue, β-Cells and Metabolome

Inhibition of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase is associated with an increased risk of new-onset type 2 diabetes. We studied the association of genetic or pharmacological HMG-CoA reductase inhibition with plasma and adipose tissue (AT) metabolome and AT metabolic pathways. We also investigated the effects of statin-mediated pharmacological inhibition of HMG-CoA reductase on systemic insulin sensitivity by measuring the HOMA-IR index in subjects with or without statin therapy. The direct effects of simvastatin (20-250 nM) or its active metabolite simvastatin hydroxy acid (SA) (8-30 nM) were investigated on human adipocyte glucose uptake, lipolysis, and differentiation and pancreatic insulin secretion. We observed that the LDL-lowering HMGCR rs12916-T allele was negatively associated with plasma phosphatidylcholines and sphingomyelins, and HMGCR expression in AT was correlated with various metabolic and mitochondrial pathways. Clinical data showed that statin treatment was associated with HOMA-IR index after adjustment for age, sex, BMI, HbA1c, LDL-c levels, and diabetes status in the subjects. Supra-therapeutic concentrations of simvastatin reduced glucose uptake in adipocytes and normalized fatty acid-induced insulin hypersecretion from β-cells. Our data suggest that inhibition of HMG-CoA reductase is associated with insulin resistance. However, statins have a very mild direct effect on AT and pancreas, hence, other tissues as the liver or muscle appear to be of greater importance.

Effect of coenzyme Q10 supplementation on oxidative stress and clinical outcomes in patients with low levels of coenzyme Q10 admitted to the intensive care unit

Today, trauma is known to be the third leading cause of death in most countries. Studies have demonstrated below-normal plasma levels of antioxidants in trauma patients. The present study aimed to assess the efficacy of Coenzyme Q10 (CoQ10) on oxidative stress, clinical outcomes and anthropometrical parameters in traumatic mechanical ventilated patients admitted to the intensive care unit. Patients were randomised to receive sublingual CoQ10 (400 mg/d) or placebo for 7 d. Primary and secondary outcomes were measured at the baseline and end of the study. We enrolled forty patients for this trial: twenty in the CoQ10 group and twenty in the placebo group. There was not any significant difference in the baseline variables (P > 0⋅05). At the end of the study, CoQ10 administration caused a considerable reduction in the Malondialdehyde (MDA) and Interleukin 6 (IL-6) concentrations (P < 0⋅001), Glasgow Coma Score (GCS; P = 0⋅02), ICU and hospital length of stay and mechanical ventilation (MV) duration (P < 0⋅001). We found that CoQ10 administration could increase Fat-Free Mass (P < 0⋅001) (FFM; P = 0⋅04), Skeletal Muscle Mass (SMM; P = 0⋅04) and Body Cell Mass (BCM) percent (P = 0⋅03). There was not any significant difference in other factors between the two groups (P > 0⋅05). CoQ10 administration has beneficial effects on patients with traumatic injury and has no side effects. However, since the possibility of the type II error was high, the outcomes on the duration of MV, ICU stay and hospital stay, and GCS may very well be false positives.

N-Acetylcysteine Reduces the Pro-Oxidant and Inflammatory Responses during Pancreatitis and Pancreas Tumorigenesis

Pancreatitis, an inflammation of the pancreas, appears to be a main driver of pancreatic cancer when combined with Kras mutations. In this context, the exact redox mechanisms are not clearly elucidated. Herein, we treated mice expressing a Kras^G12D mutation in pancreatic acinar cells with cerulein to induce acute pancreatitis. In the presence of Kras^G12D, pancreatitis triggered significantly greater redox unbalance and oxidative damages compared to control mice expressing wild-type Kras alleles. Further analyses identified the disruption in glutathione metabolism as the main redox event occurring during pancreatitis. Compared to the wild-type background, Kras^G12D-bearing mice showed a greater responsiveness to treatment with a thiol-containing compound, N-acetylcysteine (NAC). Notably, NAC treatment increased the pancreatic glutathione pool, reduced systemic markers related to pancreatic and liver damages, limited the extent of pancreatic edema and fibrosis as well as reduced systemic and pancreatic oxidative damages. The protective effects of NAC were, at least, partly due to a decrease in the production of tumor necrosis factor-α (TNF-α) by acinar cells, which was concomitant with the inhibition of NF-κB(p65) nuclear translocation. Our data provide a rationale to use thiol-containing compounds as an adjuvant therapy to alleviate the severity of inflammation during pancreatitis and pancreatic tumorigenesis.

Effects of statins on mitochondrial pathways

Statins are a family of drugs that are used for treating hyperlipidaemia with a recognized capacity to prevent cardiovascular disease events. They inhibit β-hydroxy β-methylglutaryl-coenzyme A reductase, i.e. the rate-limiting enzyme in mevalonate pathway, reduce endogenous cholesterol synthesis, and increase low-density lipoprotein clearance by promoting low-density lipoprotein receptor expression mainly in the hepatocytes. Statins have pleiotropic effects including stabilization of atherosclerotic plaques, immunomodulation, anti-inflammatory properties, improvement of endothelial function, antioxidant, and anti-thrombotic action. Despite all beneficial effects, statins may elicit adverse reactions such as myopathy. Studies have shown that mitochondria play an important role in statin-induced myopathies. In this review, we aim to report the mechanisms of action of statins on mitochondrial function. Results have shown that statins have several effects on mitochondria including reduction of coenzyme Q10 level, inhibition of respiratory chain complexes, induction of mitochondrial apoptosis, dysregulation of Ca2+ metabolism, and carnitine palmitoyltransferase-2 expression. The use of statins has been associated with the onset of additional pathological conditions like diabetes and dementia as a result of interference with mitochondrial pathways by various mechanisms, such as reduction in mitochondrial oxidative phosphorylation, increase in oxidative stress, decrease in uncoupling protein 3 concentration, and interference in amyloid-β metabolism. Overall, data reported in this review suggest that statins may have major effects on mitochondrial function, and some of their adverse effects might be mediated through mitochondrial pathways.

Endothelial dysfunction in neuroprogressive disorders-causes and suggested treatments

BACKGROUND

Potential routes whereby systemic inflammation, oxidative stress and mitochondrial dysfunction may drive the development of endothelial dysfunction and atherosclerosis, even in an environment of low cholesterol, are examined.

MAIN TEXT

Key molecular players involved in the regulation of endothelial cell function are described, including PECAM-1, VE-cadherin, VEGFRs, SFK, Rho GEF TRIO, RAC-1, ITAM, SHP-2, MAPK/ERK, STAT-3, NF-κB, PI3K/AKT, eNOS, nitric oxide, miRNAs, KLF-4 and KLF-2. The key roles of platelet activation, xanthene oxidase and myeloperoxidase in the genesis of endothelial cell dysfunction and activation are detailed. The following roles of circulating reactive oxygen species (ROS), reactive nitrogen species and pro-inflammatory cytokines in the development of endothelial cell dysfunction are then described: paracrine signalling by circulating hydrogen peroxide, inhibition of eNOS and increased levels of mitochondrial ROS, including compromised mitochondrial dynamics, loss of calcium ion homeostasis and inactivation of SIRT-1-mediated signalling pathways. Next, loss of cellular redox homeostasis is considered, including further aspects of the roles of hydrogen peroxide signalling, the pathological consequences of elevated NF-κB, compromised S-nitrosylation and the development of hypernitrosylation and increased transcription of atherogenic miRNAs. These molecular aspects are then applied to neuroprogressive disorders by considering the following potential generators of endothelial dysfunction and activation in major depressive disorder, bipolar disorder and schizophrenia: NF-κB; platelet activation; atherogenic miRs; myeloperoxidase; xanthene oxidase and uric acid; and inflammation, oxidative stress, nitrosative stress and mitochondrial dysfunction.

CONCLUSIONS

Finally, on the basis of the above molecular mechanisms, details are given of potential treatment options for mitigating endothelial cell dysfunction and activation in neuroprogressive disorders.

Statins and Higher Diabetes Mellitus Risk: Incidence, Proposed Mechanisms, and Clinical Implications

3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors are ubiquitously prescribed for cardiovascular disease (CVD) prevention and treatment. However, the use of statins has been linked to the development of new-onset diabetes mellitus (NODM), which could possibly increase future CVD risk. This phenomenon necessitates a clear discussion of the possible etiologies of this relationship and its broader clinical consequences. We discuss the reported incidence of NODM in statin users through a rigorous review of data from metaanalyses of randomized control trials examining this association. We also highlight the various possible mechanisms responsible for the development of statin-induced diabetes mellitus. Finally, we examine the clinical implications of this effect on future CVD risk and identify specific patient factors that can be used for risk-stratification strategies. Data from 14 randomized control trials metaanalyses suggest a 9-33% higher risk of NODM with statin use. Several cellular, molecular, and genetic mechanisms, as well as lifestyle habits, have been identified as potential underlying factors responsible for this elevated risk. The principle mode of the diabetogenic action of statins is still unclear, though it is likely the result of a complex interplay of pancreatic and extrapancreatic effects. It is understood that patient populations with a greater predisposition to diabetes mellitus, and those with thicker epicardial adiposity are more at risk for the development of statin-induced NODM. Despite these observations, robust data from a variety of investigations suggest that the CVD preventative benefits of statin treatment significantly outweigh the risks associated with the development of NODM. Nevertheless, further study must better identify the causative mechanisms involved in this process, its natural history, and the unique factors that will help clinicians risk stratify and appropriately monitor patients on statin therapy.

Statin Treatment-Induced Development of Type 2 Diabetes: From Clinical Evidence to Mechanistic Insights

Statins are the gold-standard treatment for the prevention of primary and secondary cardiovascular disease, which is the leading cause of mortality worldwide. Despite the safety and relative tolerability of statins, observational studies, clinical trials and meta-analyses indicate an increased risk of developing new-onset type 2 diabetes mellitus (T2DM) after long-term statin treatment. It has been shown that statins can impair insulin sensitivity and secretion by pancreatic β-cells and increase insulin resistance in peripheral tissues. The mechanisms involved in these processes include, among others, impaired Ca²⁺ signaling in pancreatic β-cells, down-regulation of GLUT-4 in adipocytes and compromised insulin signaling. In addition, it has also been described that statins’ impact on epigenetics may also contribute to statin-induced T2DM via differential expression of microRNAs. This review focuses on the evidence and mechanisms by which statin therapy is associated with the development of T2DM. This review describes the multifactorial combination of effects that most likely contributes to the diabetogenic effects of statins. Clinically, these findings should encourage clinicians to consider diabetes monitoring in patients receiving statin therapy in order to ensure early diagnosis and appropriate management.

Supplementation of pyrroloquinoline quinone with atorvastatin augments mitochondrial biogenesis and attenuates low grade inflammation in obese rats

Mitochondrial dysfunction and Inflammation play a significant role in the manifestation of the co-morbidities of obesity. The study deciphered the impact of Pyrroloquinoline quinone (PQQ) per se and with Atorvastatin (ATS) on high fat, 10% fructose diet (HFFD) induced obese rats expressing low-grade inflammation, dyslipidemia, and mitochondrial dysfunction. HFFD was fed for 10 weeks followed by treatment for 5 weeks with ATS 10 or 20 mg/kg, PQQ 10 or 20 mg/kg, p.o. per se or their combinations. The impact on blood glucose, lipid profile and serum insulin, TNF-α, IL-1β, IL-18, IL-6 was estimated. Gene and protein expression of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC 1α), Sirtuin 1 (SIRT1), Mitochondrial transcriptional factor A (TFAM) and augmented mitochondrial DNA (mtDNA), NOD like receptor protein 3 (NLRP3) and Caspase 1 was assessed. Rats receiving PQQ and ATS revealed significant decrease in body weights, anthropometric parameter, and adipose tissue vis-à-vis positive control. PQQ alone and with ATS improved glucose tolerance, lipid profile, insulin indices and lowered serum levels of inflammatory cytokines IL-18, IL-1β, TNF-α and IL-6 along with a rise in adiponectin. PQQ supplementation with ATS upregulated the mRNA expression of PGC 1α, SIRT1, TFAM and augmented mtDNA while downregulating inflammatory markers NLRP3 and Caspase 1. PQQ supplementation with atorvastatin holds therapeutic promise to effectively combat mitochondrial dysfunction and chronic low-grade inflammation in obesity.

Caveolin-1 in oncogenic metabolic symbiosis

Metabolic phenotypes of cancer cells are heterogeneous and flexible as a tumor mass is a hurriedly evolving system capable of constant adaptation to oxygen and nutrient availability. The exact type of cancer metabolism arises from the combined effects of factors intrinsic to the cancer cells and factors proposed by the tumor microenvironment. As a result, a condition termed oncogenic metabolic symbiosis in which components of the tumor microenvironment (TME) promote tumor growth often occurs. Understanding how oncogenic metabolic symbiosis emerges and evolves is crucial for perceiving tumorigenesis. The process by which tumor cells reprogram their TME involves many mechanisms, including changes in intercellular communication, alterations in metabolic phenotypes of TME cells, and rearrangement of the extracellular matrix. It is possible that one molecule with a pleiotropic effect such as Caveolin-1 may affect many of these pathways. Here, we discuss the significance of Caveolin-1 in establishing metabolic symbiosis in TME.

Sesamol protects MIN6 pancreatic beta cells against simvastatin-induced toxicity by restoring mitochondrial membrane potentials

Statins, the drugs for the treatment of dyslipidemia, have been suggested to impact insulin sensitivity, resulting in pancreatic β-cell dysfunction, and consequently, lead to new onset of diabetes. Taking this as a clue, the present study was designed to evaluate the protective effect of sesamol (a known antioxidant, antidiabetic and antidyslipidemic agent) against the diabetogenic potential of simvastatin. The toxic effects of simvastatin and sesamol on MIN6 insulinoma (Mouse pancreatic β cells) cells were evaluated separately by MTT assay. The protective effect of sesamol was evaluated at the IC₅₀ value of simvastatin at doses ranging from 7.8 to 62.5 micromolar (µM). Further, the reversal of the impact of simvastatin on cell cycle and mitochondrial membrane potential by sesamol pretreatment was studied. The IC₅₀ for simvastatin and sesamol were found to be 70.05 ± 2.34 μM and 2134 ± 8.41 μM, respectively, after 48 h and 72 h of incubation. Sesamol pretreatment protected the MIN6 cells from simvastatin toxicity (70 µM) in a dose-dependent manner from 7.8 to 31.25 µM. Simvastatin induced cell cycle arrest in G₀/G₁ phase. However, when cells were preincubated with sesamol for 24 h, a reversal in the cell cycle arrest was observed in simvastatin-treated cells (G₀/G₁). Pretreatment with sesamol also reduced the mitochondrial membrane potential loss compared to simvastatin treatment alone. These in vitro findings indicate that sesamol has a protective effect against simvastatin-induced toxicity on the pancreatic beta cells.

Atorvastatin-induced senescence of hepatocellular carcinoma is mediated by downregulation of hTERT through the suppression of the IL-6/STAT3 pathway

Hepatocellular carcinoma (HCC), a hepatic malignancy, has a poor prognosis and contributes to cancer-related death worldwide. Cellular senescence is an anticancer therapeutic strategy that causes irreversible cell cycle arrest and enables immune-mediated clearance of cancer cells. Atorvastatin, an HMG-CoA reductase inhibitor, has been shown to inhibit tumor growth and induce apoptosis or autophagy in malignant tumors. However, whether atorvastatin can induce HCC cell senescence and the mechanisms involved are poorly understood. The effects of atorvastatin-induced senescence were examined in both HCC cells and mouse xenograft models. The phenomenon and mechanism of senescence were examined by cell cycle analysis, senescence-associated β-galactosidase (SA-β-gal) staining and western blotting in HCC cells, and HCC tissues from mice were analyzed by immunohistochemical (IHC) staining. We demonstrated that atorvastatin induced cell growth inhibition and G0/G1 phase cell cycle arrest, leading to senescence in HCC cells. Atorvastatin-induced senescence was independent of p53, p14, and p16, and atorvastatin not only decreased the secretion of IL-6, a major senescence-associated secretory phenotype (SASP) factor, and the phosphorylation of STAT3 but also inhibited the expression of hTERT, a catalytic subunit of telomerase. Supplementation with exogenous IL-6 reversed both atorvastatin-induced suppression of STAT3 phosphorylation and hTERT expression and atorvastatin-induced senescence. Overexpression of constitutively activated STAT3 rescued HCC cells from atorvastatin-induced hTERT suppression and senescence. Moreover, atorvastatin decreased tumor growth in mouse xenograft models. Consistent with these results, atorvastatin decreased the IL-6, p-STAT3, and hTERT levels and increased β-gal expression in tumor sections. Taken together, these data indicate that atorvastatin can induce atypical cellular senescence in HCC cells to inhibit tumor growth, an effect mediated by downregulation of hTERT through suppression of the IL-6/STAT3 pathway.

High-fat diet induced alteration in lipid enzymes and inflammation in cardiac and brain tissues: Assessment of the effects of Atorvastatin-loaded nanoparticles

Treatment with Lipitor is associated with several adverse impacts. Here we investigated the effects of low Lipitor nanoparticles (atorvastatin calcium nanopartilcle [AC-NP]), with size less than 100 , on enzymes of lipid metabolism and inflammation in cardiac, hepatic, and brain tissues of hypercholestremic adult male rats. Adult male rats were divided into five experimental groups. In group 1, the intact control (normal pellet diet), animals were fed a normal control diet; the other four groups were fed a high-fat diet (HFD) for 6 weeks. After 6 weeks, groups from 2 to 5 were assigned as a positive control (HFD), HFD + Lipitor, HFD + AC-NP-R1, or HFD + AC-NP-R2. Different treatments were administrated orally for two regimen periods (R1 daily and R2 once every 3 days). The treatment was conducted for two consecutive weeks. The HFD group faced a significant elevation in 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA), associated with a significant reduction in low-density lipoprotein receptor (LDL-R) along with cholesterol 7 α-hydroxylase enzyme in hepatic tissues, compared with the control group. Also, the HFD group induced hepatic, cardiac, and brain inflammation, evidenced by increased hepatic oxidative stress markers and cardiac homocysteine, together with elevated proinflammatory cytokines interleukin-1β (IL-1β) and IL-6 levels in brain tissue, compared with the control group. Different AC-NP treatments significantly augmented both mRNA LDL-R and mRNA 7α-hydroxylase expression in hepatic tissues, associated with significant depletion in mRNA HMG-CoA expression, compared with HFD + Lipitor. The inflammation symptoms were ameliorated by the AC-NP treatments, compared to HFD + Lipitor. Lipitor encapsulation in NP formulation results in increased efficiency and reduced dose-related adverse effects known to be associated with the Lipitor chronic administration.

Interactions between Atorvastatin and the Farnesoid X Receptor Impair Insulinotropic Effects of Bile Acids and Modulate Diabetogenic Risk

Bile acids such as chenodeoxycholic acid (CDC) acutely enhance insulin secretion via the farnesoid X receptor (FXR). Statins, which are frequently prescribed for patients with type 2 diabetes who suffer from dyslipidemia, are known for their diabetogenic risk and are reported to interact with the FXR. Our study investigates whether this interaction is relevant for beta cell signaling and plays a role for negative effects of statins on glycemic control. Experiments were performed with islets and islet cells from C57BL/6N wild-type and FXR-knockout (KO) mice. Culturing islets with atorvastatin (15 µM) for 24 hours decreased glucose-stimulated insulin secretion by approximately 30% without affecting ATP synthesis. Prolonged exposure for 7 days lowered the concentration necessary for impairment of insulin release to 150 nM. After 24-hour culture with atorvastatin, the ability of CDC (500 nM) to elevate [Ca²⁺]_c was diminished and the potentiating effect on insulin secretion was completely lost. Mevalonate largely reduced the negative effect of atorvastatin. Nuclear activity of FXR was reduced by atorvastatin in a mouse FXR reporter assay. The atorvastatin-induced decrease in insulin release was also present in FXR-KO mice. Although not a prerequisite, FXR seems to influence the degree of damage caused by atorvastatin depending on its interaction with CDC: Preparations responding to CDC with an increase in insulin secretion under control conditions were less impaired by atorvastatin than preparations that were nonresponsive to CDC. Extended stimulation of FXR by the synthetic agonist GW4064, which is suggested to induce translocation of FXR from the cytosol into the nucleus, increased the inhibitory effect of atorvastatin. In conclusion, atorvastatin inhibits insulin release and prevents positive effects of bile acids on beta cell function. Both interactions may contribute to progression of type 2 diabetes mellitus. SIGNIFICANCE STATEMENT: This study shows that the diabetogenic risk of statins is coupled to the activity of farnesoid X receptor (FXR)-dependent signaling pathways in beta cells. On the one hand, statins abolish the insulinotropic effects of bile acids and on the other hand, FXR determines the level of impairment of islet function by the statin.

Atorvastatin Targets the Islet Mevalonate Pathway to Dysregulate mTOR Signaling and Reduce β-Cell Functional Mass

Statins are cholesterol-lowering agents that increase the incidence of diabetes and impair glucose tolerance via their detrimental effects on nonhepatic tissues, such as pancreatic islets, but the underlying mechanism has not been determined. In atorvastatin (ator)-treated high-fat diet-fed mice, we found reduced pancreatic β-cell size and β-cell mass, fewer mature insulin granules, and reduced insulin secretion and glucose tolerance. Transcriptome profiling of primary pancreatic islets showed that ator inhibited the expression of pancreatic transcription factor, mechanistic target of rapamycin (mTOR) signaling, and small G protein (sGP) genes. Supplementation of the mevalonate pathway intermediate geranylgeranyl pyrophosphate (GGPP), which is produced by 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, significantly restored the attenuated mTOR activity, v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) expression, and β-cell function after ator, lovastatin, rosuvastatin, and fluvastatin treatment; this effect was potentially mediated by sGP prenylation. Rab5a, the sGP in pancreatic islets most affected by ator treatment, was found to positively regulate mTOR signaling and β-cell function. Rab5a knockdown mimicked the effect of ator treatment on β-cells. Thus, ator impairs β-cell function by regulating sGPs, for example, Rab5a, which subsequently attenuates islet mTOR signaling and reduces functional β-cell mass. GGPP supplementation could constitute a new approach for preventing statin-induced hyperglycemia.

Impaired glucagon suppression and reduced insulin sensitivity in subjects with prediabetes undergoing atorvastatin therapy

OBJECTIVE

Statin therapy has been linked to an increased risk of type 2 diabetes in high-risk populations; however, the pathophysiology of this association remains to be clarified. We investigated glucagon suppression and its relationship with insulin resistance in prediabetic subjects undergoing atorvastatin therapy; in addition, we studied molecular insulin signaling in pancreatic α-cells exposed to atorvastatin in vitro.

DESIGN AND METHODS

Fifty subjects with prediabetes were divided into two groups based on atorvastatin therapy. All subjects underwent an oral glucose tolerance test. Early (0-30 min), late (30-120 min) and overall (0-120 min) glucagon suppression were evaluated. Insulin sensitivity was estimated by the insulin sensitivity index (ISI0-120). Insulin signaling pathway and insulin-mediated glucagon suppression were investigated in pancreatic αTC1-6 cells chronically exposed (24 or 48 h) to atorvastatin (100 ng/mL).

RESULTS

Individuals on statin therapy (n = 26) showed a significantly reduced early (0-30 min) (P = 0.003) and overall (0-120 min) (P = 0.01) glucagon suppression compared with controls (n = 24). In multivariate regression analysis, early glucagon suppression (0-30 min) exhibited a significant correlation with statin therapy. Regression analysis showed a significant association between ISI 0-120 and early0-30 (r = 0.33, P < 0.05) and overall0-120 (r = 0.38, P < 0.05) glucagon suppression. Moreover, in αTC1-6 cells atorvastatin treatment affected insulin-mediated glucagon suppression, insulin receptor phosphorylation and IRS-1-AKT pathway signaling.

CONCLUSIONS

Prediabetic patients undergoing statin therapy exhibit impaired glucagon suppression associated with lower insulin sensitivity. Our data revealed a new molecular aspect behind the deregulation of insulin sensitivity secondary to statin exposure.

Nutrient Metabolism, Subcellular Redox State, and Oxidative Stress in Pancreatic Islets and β-Cells

Insulin-secreting pancreatic β-cells play a critical role in blood glucose homeostasis and the development of type 2 diabetes (T2D) in the context of insulin resistance. Based on data obtained at the whole cell level using poorly specific chemical probes, reactive oxygen species (ROS) such as superoxide and hydrogen peroxide have been proposed to contribute to the stimulation of insulin secretion by nutrients (positive role) and to the alterations of cell survival and secretory function in T2D (negative role). This raised the controversial hypothesis that any attempt to decrease β-cell oxidative stress and apoptosis in T2D would further impair insulin secretion. Over the last decade, the development of genetically-encoded redox probes that can be targeted to cellular compartments of interest and are specific of redox couples allowed the evaluation of short- and long-term effects of nutrients on β-cell redox changes at the subcellular level. The data indicated that the nutrient regulation of β-cell redox signaling and ROS toxicity is far more complex than previously thought and that the subcellular compartmentation of these processes cannot be neglected when evaluating the mechanisms of ROS production or the efficacy of antioxidant enzymes and antioxidant drugs under glucolipotoxic conditions and in T2D. In this review, we present what is currently known about the compartmentation of redox homeostatic systems and tools to investigate it. We then review data about the effects of nutrients on β-cell subcellular redox state under normal conditions and in the context of T2D and discuss challenges and opportunities in the field.

Serum coding and non-coding RNAs as biomarkers of NAFLD and fibrosis severity

BACKGROUND & AIMS

In patients with non-alcoholic fatty liver disease (NAFLD), liver biopsy is the gold standard to detect non-alcoholic steatohepatitis (NASH) and stage liver fibrosis. We aimed to identify differentially expressed mRNAs and non-coding RNAs in serum samples of biopsy-diagnosed mild and severe NAFLD patients with respect to controls and to each other.

METHODS

We first performed a whole transcriptome analysis through microarray (n = 12: four Control: CTRL; four mild NAFLD: NAS ≤ 4 F0; four severe NAFLD NAS ≥ 5 F3), followed by validation of selected transcripts through real-time PCRs in an independent internal cohort of 88 subjects (63 NAFLD, 25 CTRL) and in an external cohort of 50 NAFLD patients. A similar analysis was also performed on liver biopsies and HepG2 cells exposed to oleate:palmitate or only palmitate (cellular model of NAFL/NASH) at intracellular/extracellular levels. Transcript correlation with histological/clinical data was also analysed.

RESULTS

We identified several differentially expressed coding/non-coding RNAs in each group of the study cohort. We validated the up-regulation of UBE2V1, BNIP3L mRNAs, RP11-128N14.5 lncRNA, TGFB2/TGFB2-OT1 coding/lncRNA in patients with NAS ≥ 5 (vs NAS ≤ 4) and the up-regulation of HBA2 mRNA, TGFB2/TGFB2-OT1 coding/lncRNA in patients with Fibrosis stages = 3-4 (vs F = 0-2). In in vitro models: UBE2V1, RP11-128N14.5 and TGFB2/TGFB2-OT1 had an increasing expression trend ranging from CTRL to oleate:palmitate or only palmitate-treated cells both at intracellular and extracellular level, while BNIP3L was up-regulated only at extracellular level. UBE2V1, RP11-128N14.5, TGFB2/TGFB2-OT1 and HBA2 up-regulation was also observed at histological level. UBE2V1, RP11-128N14.5, BNIP3L and TGFB2/TGFB2-OT1 correlated with histological/biochemical data. Combinations of TGFB2/TGFB2-OT1 + Fibrosis Index based on the four factors (FIB-4) showed an Area Under the Curve (AUC) of 0.891 (P = 3.00E-06) or TGFB2/TGFB2-OT1 + Fibroscan (AUC = 0.892, P = 2.00E-06) improved the detection of F = 3-4 with respect to F = 0-2 fibrosis stages.

CONCLUSIONS

We identified specific serum coding/non-coding RNA profiles in severe and mild NAFLD patients that possibly mirror the molecular mechanisms underlying NAFLD progression towards NASH/fibrosis. TGFB2/TGFB2-OT1 detection improves FIB-4/Fibroscan diagnostic performance for advanced fibrosis discrimination.

Drug-Induced Mitochondrial Toxicity in the Geriatric Population: Challenges and Future Directions

Mitochondrial function declines with age, leading to a variety of age-related diseases (metabolic, central nervous system-related, cancer, etc.) and medication usage increases with age due to the increase in diseases. Drug-induced mitochondrial toxicity has been described for many different drug classes and can lead to liver, muscle, kidney and central nervous system injury and, in rare cases, to death. Many of the most prescribed medications in the geriatric population carry mitochondrial liabilities. We have demonstrated that, over the past decade, each class of drugs that demonstrated mitochondrial toxicity contained drugs with both more and less adverse effects on mitochondria. As patient treatment is often essential, we suggest using medication(s) with the best safety profile and the avoidance of concurrent usage of multiple medications that carry mitochondrial liabilities. In addition, we also recommend lifestyle changes to further improve one’s mitochondrial function, such as weight loss, exercise and nutrition.

Immunometabolism and Pulmonary Infections: Implications for Protective Immune Responses and Host-Directed Therapies

The biology and clinical efficacy of immune cells from patients with infectious diseases or cancer are associated with metabolic programming. Host immune- and stromal-cell genetic and epigenetic signatures in response to the invading pathogen shape disease pathophysiology and disease outcomes. Directly linked to the immunometabolic axis is the role of the host microbiome, which is also discussed here in the context of productive immune responses to lung infections. We also present host-directed therapies (HDT) as a clinically viable strategy to refocus dysregulated immunometabolism in patients with infectious diseases, which requires validation in early phase clinical trials as adjuncts to conventional antimicrobial therapy. These efforts are expected to be continuously supported by newly generated basic and translational research data to gain a better understanding of disease pathology while devising new molecularly defined platforms and therapeutic options to improve the treatment of patients with pulmonary infections, particularly in relation to multidrug-resistant pathogens.

HbA1c showed a positive association with carcinoembryonic antigen (CEA) level in only diabetes, not prediabetic or normal individuals

Background

This study was conducted to investigate the association of carcinoembryonic antigen (CEA) and glycated hemoglobin (HbA1c) in normal, prediabetic, and diabetic subjects.

Methods

A total of 2,911 participants who underwent general health checkups were enrolled and categorized into the normal, prediabetes, and diabetes groups. Demographic, anthropological, and clinical variables were investigated, and correlations with CEA were analyzed. For 28 diabetic subjects with CEA levels above the upper limit, the follow‐up CEA and HbA1c data were analyzed.

Results

Carcinoembryonic antigen levels were significantly different among the normal, prediabetes, and diabetes groups (1.7 ± 1.1 vs 2.0 ± 1.1 vs 2.5 ± 1.5; P < 0.001), and men had higher CEA levels than women in all three groups. Correlation analysis identified a significant positive correlation between serum CEA and HbA1c in the diabetes group using unadjusted and adjusted models (r = 0.189, P < 0.001 and r = 0.218, P < 0.001), and multiple linear regression analysis also revealed that HbA1c was independently and positively correlated with CEA in the diabetes group (β = 0.275, P < 0.001). However, these relationships were inconsistent in the normal and prediabetes groups. The changes in CEA and HbA1c from baseline to follow‐up (delta CEA and delta HbA1c) showed a significant positive correlation (P = 0.021).

Conclusions

In diabetes, the CEA level was independently and positively correlated with glycemic control status. Additionally, the change in CEA level (delta CEA) showed a positive correlation with the change in HbA1c level (delta HbA1c) in the follow‐up data analysis.

Glucose homeostasis in statin users-The LIFESTAT study

BACKGROUND

Statins are widely used to lower cholesterol concentrations in both primary and secondary prevention of cardiovascular disease. The treatment increases the risk of muscle pain (myalgia) and of type 2 diabetes. However, the underlying mechanisms remain disputed.

METHODS

We investigated whether statin induced myalgia is coupled to impaired glucose homeostasis using oral glucose tolerance test (OGTT), intravenous glucose tolerance test (IVGTT), and the hyperinsulinemic euglycemic clamp. We performed a cross-sectional study of statin users without CVD (primary prevention) stratified into a statin myalgic (M; n = 25) and a non-myalgic (NM; n = 39) group as well as a control group (C; n = 20) consisting of non-statin users.

RESULTS

A reduction in the insulin secretion rate during the OGTT was observed in the myalgic group compared with the non-myalgic group (AUC ISR_OGTT , C: 1032 (683 - 1500); M: 922 (678 - 1091); NM: 1089 (933 - 1391) pmol·L^-1 ·min (median with 25%-75% percentiles), but no other measurements indicated impaired β-cell function. We found no other differences between the three groups for other measurements in the OGTT, IVGTT, and euglycemic clamp. Muscle protein content of GLUT4 and hexokinase II was similar between the three groups.

CONCLUSIONS

We conclude that statin users in primary prevention experiencing myalgia do not have impaired glucose homeostasis compared with other statin users or non-users. We consider this an important aspect in the dialogue between physician and patient regarding statin treatment and adverse effects.

Effects of a common pharmaceutical, atorvastatin, on energy metabolism and detoxification mechanisms of a marine bivalve Mytilus edulis

Biologically active compounds from pharmaceuticals cause concern due to their common occurrence in water and sediments of urbanized coasts and potential threat to marine organisms. Atorvastatin (ATO), a globally prescribed drug, is environmentally stable and bioavailable to marine organisms; however, the physiological and toxic effects of this drug on ecologically important coastal species are yet to be elucidated. We studied the effect of ATO (˜1.2 μg L^-1) on bioenergetics (including whole-organism and mitochondrial respiration, as well as tissue energy reserves and mRNA expression of genes involved in mitochondrial biogenesis and fatty acid metabolism in the gills and the digestive gland) of a keystone bivalve Mytulis edulis (the blue mussel) from the Baltic Sea. Xenobiotic detoxification systems including activity and mRNA expression of P-glycoprotein, and Phase I and II biotransformation enzymes (cytochrome P450 monooxygenase CYP1A and glutathione transferase, GST) were also assessed in the gill and digestive gland of the mussels. Exposure to ATO caused rapid uptake and biotransformation of the drug by the mussels. Standard metabolic rate of ATO-exposed mussels increased by 56% indicating higher maintenance costs, yet no changes were detected in the respiratory capacity of isolated mitochondria. ATO exposure led to ˜60% decrease in the lysosomal membrane stability of hemocytes and ˜3-fold decrease in the whole-organism P-glycoprotein-driven and diffusional efflux of xenobiotics indicating altered membrane properties. The digestive gland was a major target of ATO toxicity in the mussels. Exposure of mussels to ATO led to depletion of lipid, carbohydrate and protein pools, and suppressed transcription of key enzymes involved in mitochondrial biogenesis (peroxisome proliferator-activated receptor gamma coactivator 1-alpha PGC-1α) and fatty acid metabolism (acetyl-CoA carboxylase and CYP4Y1) in the digestive gland. No bioenergetic disturbances were observed in the gills of ATO-exposed mussels, and elevated GST activity indicated enhanced ATO detoxification in this tissue. These data demonstrate that ATO can act as a metabolic disruptor and chemosensitizer in keystone marine bivalves and warrant further investigations of statins as emerging pollutants of concern in coastal marine ecosystems.

Future perspectives of the pharmacological management of diabetic dyslipidemia

INTRODUCTION

Diabetic dyslipidemia is frequent among patients with type 2 diabetes mellitus (T2DM) and is characterized by an increase in triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and small-dense (atherogenic) particles, and by a decrease in low high-density lipoprotein cholesterol (HDL-C) and apolipoprotein (Apo) A1 that are strongly related to insulin resistance. The increased flux of free fatty acids from adipose tissue to the liver aggravates hepatic insulin resistance and promotes all of aspects of the dyslipidemic state. Areas covered: Statins are the first-line agents for treatment while other lipid-lowering drugs (ezetimibe, fibrate and proprotein convertase subtilisin/kexin type 9) or novel anti-diabetic agents (dipeptidyl peptidase-4 inhibitors (DPP-4is), glucagon like peptide-1 receptor agonist (GLP-1RA), sodium/glucose cotransporter 2 inhibitors (SGLT2is)) or nutraceuticals (berberine, omega 3 fatty acid, red yeast rice) can be used alone or in combination. Expert commentary: In patients with T2DM, lipid abnormalities should be identified and treated as part of the overall diabetic treatment, in order to prevent cardiovascular disease. The choice of drugs to be used is mainly based on the lipid profile and on the characteristic lipoprotein abnormalities; the use of new drugs for the treatment of hyperglycemia and lipids alteration in these patients can improve diabetic dyslipidemia.

Effects of rosuvastatin on metabolic profile: Versatility of dose-dependent effect

Obesity refers to an excess of body fat content causing metabolic and inflammatory disorders. Therefore, the aim of the present study was to investigate dose-dependent effect of rosuvastatin on the metabolic profile of diet-induced obesity in mice model study. A total number of 40 male Albino Swiss mice were used which divided into Group I: Control group, fed normal diet for 8 weeks (n = 10); Group II: High-fat diet (HFD) group, fed on HFD for 8 weeks (n = 10); Group III: HFD + 20 mg/kg rosuvastatin for 8 weeks (n = 10); and Group IV: HFD +40 mg/kg rosuvastatin for 8 weeks (n = 10). Anthropometric and biochemical parameters were estimated, including fasting blood glucose, lipid profile, fasting insulin, and glucose tolerance test (GTT). Mice on HFD fed showed a significant increase in the insulin resistance, body weight, deterioration of lipid profile and significant reduction in the β-cell function, and insulin sensitivity compared to the control P < 0.05. GTT and blood glucose level were significantly high in HFD fed group compared to the control group P < 0.05. Rosuvastatin in a dose of 40 mg/kg illustrated better effect than 20 mg/kg on the glucometabolic profile P < 0.05. Rosuvastatin may has a potential effect on reduction of glucometabolic changes induced by HFD with significant amelioration of pancreatic β-cell function in dose-dependent manner.

Interaction of statins with phospholipid bilayers studied by solid-state NMR spectroscopy

Statins are drugs that specifically inhibit the enzyme HMG-CoA reductase and thereby reduce the concentration of low-density lipoprotein cholesterol, which represents a well-established risk factor for the development of atherosclerosis. The results of several clinical trials have shown that there are important intermolecular differences responsible for the broader pharmacologic actions of statins, even beyond HMG-CoA reductase inhibition. According to one hypothesis, the biological effects exerted by these compounds depend on their localization in the cellular membrane. The aim of the current work was to study the interactions of different statins with phospholipid membranes and to investigate their influence on the membrane structure and dynamics using various solid-state NMR techniques. Using ¹H NOESY MAS NMR, it was shown that atorvastatin, cerivastatin, fluvastatin, rosuvastatin, and some percentage of pravastatin intercalate the lipid-water interface of POPC membranes to different degrees. Based on cross-relaxation rates, the different average distribution of the individual statins in the bilayer was determined quantitatively. Investigation of the influence of the investigated statins on membrane structure revealed that lovastatin had the least effect on lipid packing and chain order, pravastatin significantly lowered lipid chain order, while the other statins slightly decreased lipid chain order parameters mostly in the middle segments of the phospholipid chains.

Chronic Exposure to Palmitate Impairs Insulin Signaling in an Intestinal L-cell Line: A Possible Shift from GLP-1 to Glucagon Production

Obesity and type 2 diabetes mellitus (T2DM) are characterized by insulin resistance and impaired glucagon-like peptide-1 (GLP-1) secretion/function. Lipotoxicity, a chronic elevation of free fatty acids in the blood, could affect insulin-signaling in many peripheral tissues. To date, the effects of lipotoxicity on the insulin receptor and insulin resistance in the intestinal L-cells need to be elucidated. Moreover, recent observations indicate that L-cells may be able to process not only GLP-1 but also glucagon from proglucagon. The aim of this study was to investigate the effects of chronic palmitate exposure on insulin pathways, GLP-1 secretion and glucagon synthesis in the GLUTag L-cell line. Cells were cultured in the presence/absence of palmitate (0.5 mM) for 24 h to mimic lipotoxicity. Palmitate treatment affected insulin-stimulated GLP-1 secretion, insulin receptor phosphorylation and IRS-1-AKT pathway signaling. In our model lipotoxicity induced extracellular signal-regulated kinase (ERK 44/42) activation both in insulin stimulated and basal conditions and also up-regulated paired box 6 (PAX6) and proglucagon expression (Gcg). Interestingly, palmitate treatment caused an increased glucagon secretion through the up-regulation of prohormone convertase 2. These results indicate that a state of insulin resistance could be responsible for secretory alterations in L-cells through the impairment of insulin-signaling pathways. Our data support the hypothesis that lipotoxicity might contribute to L-cell deregulation.

Pitavastatin Upregulates Nitric Oxide Synthases in the Kidney of Spontaneously Hypertensive Rats and Wistar-Kyoto Rats

BACKGROUND

Clinical trials show potent renoprotective effects of pitavastatin (PTV), although the precise mechanism for these renoprotective effects is not fully clarified. The aim of this study was to examine the antihypertensive and renoprotective effects of PTV, focusing on the nitric oxide (NO) system.

METHODS

Male, 6-week-old, spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were randomized to receive vehicle or PTV (2 mg/kg bodyweight) for 8 weeks. Blood pressure and urinary albumin excretion were measured every 2 weeks. After 8 weeks, plasma biochemical parameters and renal histology were examined. NO synthase isoform (neuronal, nNOS; inducible, iNOS; and endothelial, eNOS) expression and eNOS phosphorylation were examined by western blotting.

RESULTS

PTV attenuated hypertension and albuminuria development in SHR. PTV decreased glomerular desmin expression and medullary interstitial fibrosis in SHR. PTV tended to increase plasma NO in both strains but significantly increased urinary NO excretion only in WKY. PTV significantly increased nNOS and eNOS expression, enhanced eNOS phosphorylation at serine1177, and inhibited eNOS phosphorylation at threonine495 in the kidney of both strains.

CONCLUSIONS

PTV treatment led to increased renal NOS expression and upregulated eNOS activity in both SHR and WKY. The antihypertensive and renoprotective effects of PTV may be related to upregulation of the NO system.

Coenzyme Q10 or Creatine Counteract Pravastatin-Induced Liver Redox Changes in Hypercholesterolemic Mice

Statins are the preferred therapy to treat hypercholesterolemia. Their main action consists of inhibiting the cholesterol biosynthesis pathway. Previous studies report mitochondrial oxidative stress and membrane permeability transition (MPT) of several experimental models submitted to diverse statins treatments. The aim of the present study was to investigate whether chronic treatment with the hydrophilic pravastatin induces hepatotoxicity in LDL receptor knockout mice (LDLr-/-), a model for human familial hypercholesterolemia. We evaluated respiration and reactive oxygen production rates, cyclosporine-A sensitive mitochondrial calcium release, antioxidant enzyme activities in liver mitochondria or homogenates obtained from LDLr-/- mice treated with pravastatin for 3 months. We observed that pravastatin induced higher H2O2 production rate (40%), decreased activity of aconitase (28%), a superoxide-sensitive Krebs cycle enzyme, and increased susceptibility to Ca2+-induced MPT (32%) in liver mitochondria. Among several antioxidant enzymes, only glucose-6-phosphate dehydrogenase (G6PD) activity was increased (44%) in the liver of treated mice. Reduced glutathione content and reduced to oxidized glutathione ratio were increased in livers of pravastatin treated mice (1.5- and 2-fold, respectively). The presence of oxidized lipid species were detected in pravastatin group but protein oxidation markers (carbonyl and SH- groups) were not altered. Diet supplementation with the antioxidants CoQ10 or creatine fully reversed all pravastatin effects (reduced H2O2 generation, susceptibility to MPT and normalized aconitase and G6PD activity). Taken together, these results suggest that 1- pravastatin induces liver mitochondrial redox imbalance that may explain the hepatic side effects reported in a small number of patients, and 2- the co-treatment with safe antioxidants neutralize these side effects.

New treatment options for lipid-lowering therapy in subjects with type 2 diabetes

Dyslipidemias represent a variety of quantitative and/or qualitative lipoprotein abnormalities. According to etiology, we distinguish primary dyslipidemias with strictly genetic background and secondary ones with their origin in other disease or pathological states. Diabetic dyslipidemia is a type of secondary dyslipidemia and plays an important role in determining the cardiovascular risk of subjects with type 2 diabetes. In these patients, insulin resistance is responsible for overproduction and secretion of atherogenic very low density lipoprotein. In addition, insulin resistance promotes the production of small dense low-density lipoprotein (LDL) and reduces high-density lipoprotein (HDL) production. Cardiovascular disease remains a leading cause of morbidity and mortality in diabetic patients. Previous results support the role for small, dense LDL particles in the etiology of atherosclerosis and their association with coronary artery disease. Moreover, lowering LDL cholesterol reduces the risk of cardiovascular death. Therefore, the European guidelines for the management of dyslipidemias recommend an LDL cholesterol goal < 100 mg/dL in diabetic subjects without cardiovascular events. Moreover, if triglycerides (TG) are elevated (> 400 mg/dL), they recommend a non-HDL cholesterol goal < 130 mg/dL in diabetic individuals without cardiovascular events. Statins are the first line of LDL-lowering therapy in diabetic patients and combined therapy with ezetimibe and statins could be useful in very high cardiovascular risk diabetic subjects. Furthermore, the effect of a fibrate as an add-on treatment to a statin could improve the lipid profile in diabetic individuals with high TG and low HDL cholesterol. Regarding new therapies, recent data from phase III trials show that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors considerably decrease LDL cholesterol. Thus, they may be useful in diabetic patients with concomitant diseases such as familial dyslipidemia, recurrent cardiovascular events, and elevated LDL cholesterol after second drug administration in addition to maximal statin dose or statin intolerance.