Protective effect of HMG CoA reductase inhibitors against running wheel activity induced fatigue, anxiety like behavior, oxidative stress and mitochondrial dysfunction in mice

The pharmacological bases for repurposing statins in depression: a review of mechanistic studies

Statins are commonly prescribed medications widely investigated for their potential actions on the brain and mental health. Pre-clinical and clinical evidence suggests that statins may play a role in the treatment of depressive disorders, but only the latter has been systematically assessed. Thus, the physiopathological mechanisms underlying statins' putative antidepressant or depressogenic effects have not been established. This review aims to gather available evidence from mechanistic studies to strengthen the pharmacological basis for repurposing statins in depression. We used a broad, well-validated search strategy over three major databases (Pubmed/MEDLINE, Embase, PsychINFO) to retrieve any mechanistic study investigating statins' effects on depression. The systematic search yielded 8068 records, which were narrowed down to 77 relevant papers. The selected studies (some dealing with more than one bodily system) described several neuropsychopharmacological (44 studies), endocrine-metabolic (17 studies), cardiovascular (6 studies) and immunological (15 studies) mechanisms potentially contributing to the effects of statins on mood. Numerous articles highlighted the beneficial effect of statins on depression, particularly through positive actions on serotonergic neurotransmission, neurogenesis and neuroplasticity, hypothalamic-pituitary axis regulation and modulation of inflammation. The role of other mechanisms, especially the association between statins, lipid metabolism and worsening of depressive symptoms, appears more controversial. Overall, most mechanistic evidence supports an antidepressant activity for statins, likely mediated by a variety of intertwined processes involving several bodily systems. Further research in this area can benefit from measuring relevant biomarkers to inform the selection of patients most likely to respond to statins' antidepressant effects while also improving our understanding of the physiopathological basis of depression.

Statins in depression: a repurposed medical treatment can provide novel insights in mental health

Depression has a large burden, but the development of new drugs for its treatment has proved difficult. Progresses in neuroscience have highlighted several physiopathological pathways, notably inflammatory and metabolic ones, likely involved in the genesis of depressive symptoms. A novel strategy proposes to repurpose established medical treatments of known safety and to investigate their potential antidepressant activity. Among numerous candidates, growing evidence suggests that statins may have a positive role in the treatment of depressive disorders, although some have raised concerns about possible depressogenic effects of these widely prescribed medications. This narrative review summarises relevant findings from translational studies implicating many interconnected neurobiological and neuropsychological, cardiovascular, endocrine-metabolic, and immunological mechanisms by which statins could influence mood. Also, the most recent clinical investigations on the effects of statins in depression are presented. Overall, the use of statins for the treatment of depressive symptoms cannot be recommended based on the available literature, though this might change as several larger, methodologically robust studies are being conducted. Nevertheless, statins can already be acknowledged as a driver of innovation in mental health, as they provide a novel perspective to the physical health of people with depression and for the development of more precise antidepressant treatments.

Synergistic antioxidant capacities of vanillin and chitosan nanoparticles against reactive oxygen species, hepatotoxicity, and genotoxicity induced by aging in male Wistar rats

This study aimed to evaluate the synergistic effects of both vanillin (V) and chitosan nanoparticles (CNPs) in alleviating hepatotoxicity, oxidative injury, and genotoxicity induced by d-galactose (DG) and resulted from aging in male albino rats. Male Wistar rats were divided into seven groups (10 rats/group) as follows: control group, (DG) group (100 mg/kg), (V) group (100 mg/kg), CNPs either (low dose (LD) or CNPs (high dose (HD) (140 mg/kg) and (280 mg/kg), and CNPs (LD and HD) dose with V- and DG plus V-treated groups. The CNPs were characterized by transmission electron microscopy (TEM), zeta potential, and size distribution of nanoparticles. After 60 consecutive days of exposure, some biochemical parameters were measured as hepatic aminotransferases enzymes, lipid profile, tumor necrosis factor alpha, interleukin-6 (IL-6), markers of inflammation, tissue damage lactate dehydrogenase, C-reactive protein (CRP), mitochondrial potential activities, myeloperoxidase, xanthine oxidase, CRP, succinate dehydrogenase, mitochondria membrane potential, malondialdehyde levels and antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase, and glutathione S-transferase), and adenosine triphosphate content with histological, alkaline comet assay, and TEM examination of the hepatic tissues. CNPs showed that size distribution (polydispersity index) 0.350 nm and the zeta potential measurement of CNPs were found to be -14.9 mV which revealed the high stability of CNPs. DG induced biochemical and cellular alterations in the hepatic tissues. CNPs and V synergistically afforded protection against hepatic injury and oxidative stress resulting from aging that was induced by DG. Consequently, CNPs were an effective agent in the drug delivery in the hepatic diseases medications and act as a carrier for V and thus make synergistic effect between CNPs and V that achieved the high antioxidant capacities. CNPs and V improved the hepatic enzymes, which act as anti-inflammatory and antigenotoxicity, and improved the antioxidant capacities in the hepatic tissues.

Statins and the Brain: More than Lipid Lowering Agents?

Background:

Statins represent a class of medications widely prescribed to efficiently treat dyslipidemia. These drugs inhibit 3-βhydroxy 3β-methylglutaryl Coenzyme A reductase (HMGR), the rate-limiting enzyme of mevalonate (MVA) pathway. Besides cholesterol, MVA pathway leads to the production of several other compounds, which are essen-tial in the regulation of a plethora of biological activities, including in the central nervous system. For these reasons, statins are able to induce pleiotropic actions, and acquire increased interest as potential and novel modulators in brain processes, es-pecially during pathological conditions.

Objective:

The purpose of this review is to summarize and examine the current knowledge about pharmacokinetic and phar-macodynamic properties of statins in the brain. In addition, effects of statin on brain diseases are discussed providing the most up-to-date information.

Methods:

Relevant scientific information was identified from PubMed database using the following keywords: statins and brain, central nervous system, neurological diseases, neurodegeneration, brain tumors, mood, stroke.

Results:

315 scientific articles were selected and analyzed for the writing of this review article. Several papers highlighted that statin treatment is effective in preventing or ameliorating the symptomatology of a number of brain pathologies. Howev-er, other studies failed to demonstrate a neuroprotective effect.

Conclusion:

Even though considerable research studies suggest pivotal functional outcomes induced by statin therapy, addi-tional investigation is required to better determine the pharmacological effectiveness of statins in the brain, and support their clinical use in the management of different neuropathologies.

Atorvastatin and insulin equally mitigate brain pathology in diabetic rats

Although insulin and atorvastatin have been shown to exert glycemic control and could improve brain function, the effects of atorvastatin or insulin as well as the combination of atorvastatin plus insulin on brain pathology in diabetes mellitus type 1 (T1DM) are unclear. Therefore, this study investigated the effect of atorvastatin, insulin or combined drugs on brain pathology in streptozotocin-induced diabetic rats. Thirty-six male rats were divided into two groups, a control group (n = 12) and a diabetic or experimental group (n = 24). Diabetic rats were further divided into four groups (n = 6/group) and the groups received either a vehicle (normal saline), atorvastatin (10 mg/kg/day), insulin (4 U/day) or a combination of the drugs for 4 weeks. The control group rats were divided into two groups (n = 6/group) to receive either just the vehicle or atorvastatin for 4 weeks. We found that streptozotocin-induced diabetic rats developed hyperglycemia, showing evidence of increased brain oxidative stress, impaired brain mitochondrial function, increased brain apoptosis, increased tau protein expression, increased phosphorylation of tau protein expression and amyloid beta levels, and decreased dendritic spine density. Although atorvastatin and insulin therapies led to an equal reduction in plasma glucose level in these diabetic rats, the combined drug therapy showed the greatest efficacy in decreasing plasma glucose level. Interestingly, atorvastatin, insulin and the combined drugs equally mitigated brain pathology. Our findings indicate that the combined drug therapy showed the greatest efficacy in improving metabolic parameters. However, atorvastatin, insulin and the combined drug therapy shared a similar efficacy in preventing brain damage in T1DM rats.

Protective effect of atorvastatin on d-galactose-induced aging model in mice

Atorvastatin (Ator), competitive inhibitors of 3-hydroxymethyl-3-glutaryl-coenzyme-A reductase, is a cholesterol lowering drug. Ator has been shown to have neuroprotective, antioxidant and anti-inflammatory properties making that a potential candidate for the treatment of central nervous system (CNS) disorders. Here we assessed the effect of Ator on the d-galactose (d-gal)-induced aging in mice. For this purpose, Ator (0.1 and 1mg/kg/p.o.), was administrated daily in d-gal-received (500mg/kg/p.o.) mice model of aging for six weeks. Anxiety-like behaviors and cognitive functions were evaluated by the elevated plus-maze and novel object recognition tasks, respectively. Physical power was assessed by forced swimming capacity test. Animals brains were analyzed for the superoxide dismutase (SOD) and brain-derived neurotrophic factor (BDNF). We found that Ator decreases the anxiety-like behaviors in d-gal-treated mice. Also, our behavioral tests showed that Ator reverses the d-gal induced learning and memory impairment. Furthermore, we found that Ator increases the physical power of d-gal-treated mice. Our results indicated that the neuroprotective effect of Ator on d-gal induced neurotoxicity is mediated, at least in part, by an increase in the SOD and BDNF levels. The results of present study suggest that Ator could be used as a novel therapeutic strategy for the treatment of age-related conditions.

Pleiotropic effects of statins: new therapeutic targets in drug design

The HMG Co-enzyme inhibitors and new lipid-modifying agents expand their new therapeutic target options in the field of medical profession. Statins have been described as the most effective class of drugs to reduce serum cholesterol levels. Since the discovery of the first statin nearly 30 years ago, these drugs have become the main therapeutic approach to lower cholesterol levels. The present scientific research demonstrates numerous non-lipid modifiable effects of statins termed as pleiotropic effects of statins, which could be beneficial for the treatment of various devastating disorders. The most important positive effects of statins are anti-inflammatory, anti-proliferative, antioxidant, immunomodulatory, neuroprotective, anti-diabetes, and antithrombotic, improving endothelial dysfunction and attenuating vascular remodeling besides many others which are discussed under the scope of this review. In particular, inhibition of Rho and its downstream target, Rho-associated coiled-coil-containing protein kinase (ROCK), and their agonistic action on peroxisome proliferator-activated receptors (PPARs) can be viewed as the principle mechanisms underlying the pleiotropic effects of statins. With gradually increasing knowledge of new therapeutic targets of statins, their use has also been advocated in chronic inflammatory disorders for example rheumatoid arthritis (RA) and in systemic lupus erythematosus (SLE). In the scope of review, we highlight statins and their pleiotropic effects with reference to their harmful and beneficial effects as a novel approach for their use in the treatment of devastating disorders. Graphical abstract Pleiotropic effect of statins.

Effects of Statin Therapy on Exercise Levels in Participants in the National Runners' and Walkers' Health Study

OBJECTIVES

To determine whether decreases in exercise 1) were greater in individuals who were diagnosed as having hypercholesterolemia than in those without the diagnosis during follow-up and 2) were greater in incident hypercholesterolemic participants starting statins than in those not treated with cholesterol-lowering medications.

PARTICIPANTS AND METHODS

Regression analyses of changes since baseline (Δ) in exercise vs diagnosis of hypercholesterolemia and its treatment in 66,377 runners and 12,031 walkers not using cholesterol medications at baseline who were resurveyed during the National Runners' and Walkers' Health Study follow-up (January 1, 1991, through December 31, 2006).

RESULTS

A total of 3510 runners began statin treatment, 1779 began other or unspecified cholesterol-lowering drug treatment, and 2583 had untreated hypercholesterolemia; 58,505 runners remained nonhypercholesterolemic controls during the mean 7.2-year follow-up. Usual distance run decreased significantly more in hypercholesterolemic runners who began taking statins (mean ± SE: -0.47±0.06 km/d) than in runners who remained nonhypercholesterolemic during follow-up (-0.08±0.02 km/d) (P<.001). However, running distance also decreased significantly more in hypercholesterolemic runners who began unspecified/other (-0.52±0.08 km/d) or no (-0.47±0.07 km/d) cholesterol drugs than in nonhypercholesterolemic runners during follow-up. Moreover, Δrunning distance did not differ significantly between hypercholesterolemic runners who were statin treated vs those treated with other/unspecified (P=.64) or no (P=.94) cholesterol drugs. Initiating statin therapy was not associated with Δrunning pace in hypercholesterolemic runners or Δwalking distances in hypercholesterolemic walkers.

CONCLUSION

These results are consistent with the premise that a decrease in running distance is associated with hypercholesterolemia and do not suggest that statins reduce exercise level or intensity.

Complexity of Compensatory Effects in Nrf1 Knockdown: Linking Undeveloped Anxiety-Like Behavior to Prevented Mitochondrial Dysfunction and Oxidative Stress

Anxiety-related disorders are complex illnesses that underlying molecular mechanisms need to be understood. Mitochondria stand as an important link between energy metabolism, oxidative stress, and anxiety. The nuclear factor, erythroid-derived 2,-like 1(Nrf1) is a member of the cap "n" collar subfamily of basic region leucine zipper transcription factors and plays the major role in regulating the adaptive response to oxidants and electrophiles within the cell. Here, we injected small interfering RNA (siRNA) targeting Nrf1 in dorsal third ventricle of adult male albino Wistar rats and subsequently examined the effect of this silencing on anxiety-related behavior. We also evaluated apoptotic markers and mitochondrial biogenesis factors, along with electron transport chain activity in three brain regions: hippocampus, amygdala, and prefrontal cortex. Our data revealed that in the group that received Nrf1-siRNA, anxiety-related behavior did not show any significant changes compared to the control group. Caspase-3 did not increase in Nrf1-siRNA-injected rats even though Bax/Bcl2 ratio markedly elevated in Nrf1-knockdown rats in all three mentioned regions compared to control rats. Also, Nrf1 silencing of complex I and II-III did not alter, generally. In addition, Nrf1-knockdown affected mitochondrial biogenesis markers. The level of peroxisome proliferator-activated receptor gamma coactivator-1α and cytochrome-c increased, which indicates a possible role for mitochondrial biogenesis in anxiety.

Minocycline modulates neuroprotective effect of hesperidin against quinolinic acid induced Huntington's disease like symptoms in rats: behavioral, biochemical, cellular and histological evidences

Emerging evidences indicate hesperidin, a citrus flavanone, attenuates neurodegenerative processes and related complications. Besides its anti-oxidant properties, the other probable mechanisms which underpin its neuroprotective potential are still not clear. In light of emerging role of flavonoids in modulating oxidative stress and neuro-inflammation, the study has been designed to explore the possible neuroprotective effect of hesperidin and its combination with minocycline (microglial inhibitor), against quinolinic acid (QA) induced Huntington's disease (HD) like symptoms in rats. Unilateral intrastriatal administration of QA (300 nmol/4 µl) significantly reduced body weight, impaired behavior (locomotor activity, beam balance and memory performance), caused oxidative damage (increased lipid peroxidation, nitrite concentration, depleted super oxide dismutase and reduced glutathione), demonstrated mitochondrial dysfunction (decreased Complex-I, II, III, and IV activities), increased striatal lesion volume and altered the levels of TNF-α, caspase-3 as well as BDNF expression, as compared to sham group. Meanwhile, chronic hesperidin (100mg/kg, p.o.) and minocycline (25mg/kg, p.o.) treatment for 21 days significantly attenuated the behavioral, biochemical and cellular alterations as compared to QA treated (control) animals, whereas hesperidin (50mg/kg, p.o.) treatment was found to be non-significant. However, treatment of hesperidin (50mg/kg) in combination with minocycline (25mg/kg) potentiated their neuroprotective effect, which was significant as compared to their effects per se in QA treated animals. Taken altogether, the results of the present study suggest a possible interplay of microglial modulation and anti-oxidant effect in neuroprotective potential of hesperidin against QA induced HD like symptoms in rats.