Atorvastatin

A Dual Pharmacological Strategy against COVID-19: The Therapeutic Potential of Metformin and Atorvastatin

Metformin (MET) and atorvastatin (ATO) are promising treatments for COVID-19. This review explores the potential of MET and ATO, commonly prescribed for diabetes and dyslipidemia, respectively, as versatile medicines against SARS-CoV-2. Due to their immunomodulatory and antiviral capabilities, as well as their cost-effectiveness and ubiquitous availability, they are highly suitable options for treating the virus. MET's effect extends beyond managing blood sugar, impacting pathways that can potentially decrease the severity and fatality rates linked with COVID-19. It can partially block mitochondrial complex I and stimulate AMPK, which indicates that it can be used more widely in managing viral infections. ATO, however, impacts cholesterol metabolism, a crucial element of the viral replicative cycle, and demonstrates anti-inflammatory characteristics that could modulate intense immune reactions in individuals with COVID-19. Retrospective investigations and clinical trials show decreased hospitalizations, severity, and mortality rates in patients receiving these medications. Nevertheless, the journey from observing something to applying it in a therapeutic setting is intricate, and the inherent diversity of the data necessitates carefully executed, forward-looking clinical trials. This review highlights the requirement for efficacious, easily obtainable, and secure COVID-19 therapeutics and identifies MET and ATO as promising treatments in this worldwide health emergency.

Optimization of transdermal atorvastatin calcium - Loaded proniosomes: Restoring lipid profile and alleviating hepatotoxicity in poloxamer 407-induced hyperlipidemia

In an attempt to optimize the anti- hyperlipidemic effect and reduce statins induced hepatotoxicity, Atorvastatin Calcium (ATC) transdermal proniosomal gel (PNG) was developed. Different non-ionic surfactants (NISs) (Spans, Tweens, Cremophor RH 40 and Brij 52) were incorporated in the vesicle's lipid bilayer, in combination with lecithin. PNG formulae were characterized for encapsulation efficiency percent (% EE), vesicle size, polydispersity index (PDI) and zeta potential (ZP). Ex-vivo permeation study was performed using full thickness rat skin measuring drug flux and skin permeability coefficients. The pharmacodynamic performance of optimized transdermal ATC- PNG on both lipid profile and liver biomarkers was assessed and compared to oral ATC administration in poloxamer 407-induced hyperlipidemic rats. The liver tissues were subjected to histological examination as well. The results revealed nano-size range vesicles with relatively high ATC entrapment efficiency. Ex-vivo results demonstrated the permeation superiority of ATC proniosomes over free drug. Pharmacodynamic study revealed that transdermal administration of ATC- PNG succeeded in retaining the anti-hyperlipidemic efficacy of orally administered ATC without elevating liver biomarkers. The histological examination signified the role of optimized ATC-PNG in hindering statin- induced hepatocellular damage. The obtained results suggested a promising, easy-to-manufacture and effective ATC proniosomal gel for safe treatment of hyperlipidemia.

Relaxant effect of atorvastatin on isolated rat gastric fundus strips: implications for Ca2+-signalling mechanisms

Statins are determined to have various pleiotropic effects apart from their lipid-lowering properties. Herein, we investigated the direct effects of atorvastatin on gastric smooth muscle tone. Atorvastatin effectively relaxed isolated rat gastric fundus strips precontracted with acetylcholine, potassium chloride, and serotonin. Incubation of the strips with nitric oxide synthase inhibitor, l-NOARG (10−4 M, 20 min), l-type voltage-operated Ca2+ channel (VOCC) blocker, nifedipine (10−6 M, 30 min), KATP channel blocker, glibenclamide (10−5 M, 30 min), or precursor of cholesterol, mevalonate (10−2 M, 45 min) did not change the relaxations to atorvastatin. However, pretreatment of fundus strips with atorvastatin (3×10−5–3×10−4 M, 30 min) inhibited the contractions to calcium chloride (10−4–10−1 M), acetylcholine (10–4 M), and caffeine (20 mM) in the calcium-free medium. Moreover, atorvastatin reduced the contractions induced by sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor, cyclopiazonic acid (10−7–3×10−5 M). The current study demonstrated that atorvastatin produces an acute relaxant effect on gastric fundus strips, which appears to be mediated by several Ca2+-signalling mechanisms such as the blockade of l-type VOCC-independent Ca2+ entry, decrease in smooth muscle Ca2+ sensitivity, inhibition of IP3- and ryanodine-sensitive intracellular stores to mediate Ca2+ release, as well as the activation of SERCA. This acute relaxing effect seems unlikely to be related with nitric oxide, KATP channels, and the mevalonate pathway.

Effects of cyclosporin A and itraconazole on the pharmacokinetics of atorvastatin in rats

AIM

To evaluate the effects of cyclosporin A and itraconazole, which were used as inhibitors of P-glycoprotein (P-gp) and/or cytochrome P450 (CYP) 3A4 on the pharmacokinetics of atorvastatin in rats.

METHODS

The pharmacokinetic parameters of atorvastatin were measured after intravenous (2 mg/kg) and intragastric (10 mg/kg) administration of atorvastatin in rats, which were pretreated with cyclosporin A (5, 10, and 20 mg/kg) or itraconazole (5, 10, and 20 mg/kg).

RESULTS

Compared with the control rats, cyclosporin A and itraconazole altered the pharmacokinetics of atorvastatin significantly. The AUC0-t values of atorvastatin after intragastric administration, pretreated with cyclosporin A (5-20 mg/kg), increased by 32.3%, 61.8%, and 187.2%, respectively, but the CLbile values decreased (P<0.01, 5-20 mg/kg). With pretreatment of itraconazole (5-20 mg/kg), the AUC(0-t) values of atorvastatin increased by 88.2%, 102%, and 123%, respectively, but the CL(bile) values decreased (P<0.01, 5-20 mg/kg).

CONCLUSION

These data indicated that cyclosporin A could be effective in inhibiting the efflux of atorvastatin, and itraconazole could be effective in inhibiting both the metabolism and biliary excretion of atorvastatin.

The Guinea pig as a preclinical model for demonstrating the efficacy and safety of statins

Statins, because of their excellent efficacy and manageable safety profile, represent a key component in the current armamentarium for the treatment of hypercholesterolemia. Nonetheless, myopathy remains a safety concern for this important drug class. Cerivastatin was withdrawn from the market for myotoxicity safety concerns. BMS-423526 [{(3R,5S)-7-[4-(4-fluorophenyl)-6,7-dihydro-2-(1-methylethyl)-5H-benzo[6,7]cyclohepta[1,2-b]pyridin-3-yl]-3,5-dihydroxy-heptenoic acid} sodium salt], similar to cerivastatin in potency and lipophilicity, was terminated in early clinical development due to an unacceptable myotoxicity profile. In this report, we describe the guinea pig as a model of statin-induced cholesterol lowering and myotoxicity and show that this model can distinguish statins with unacceptable myotoxicity profiles from statins with acceptable safety profiles. In our guinea pig model, both cerivastatin and BMS-423526 induced myotoxicity at doses near the ED(50) for total cholesterol (TC) lowering in plasma. In contrast, wide differences between myotoxic and TC-lowering doses were established for the currently marketed, more hydrophilic statins, pravastatin, rosuvastatin, and atorvastatin. This in vivo model compared favorably to an in vitro model, which used statin inhibition of cholesterol synthesis in rat hepatocytes and L6 myoblasts as surrogates of potential efficacy and toxicity, respectively. Our conclusion is that the guinea pig is a useful preclinical in vivo model for demonstrating whether a statin is likely to have an acceptable therapeutic safety margin.

Effect of ScrF I polymorphism in the 2nd intron of the HMGCR gene on lipid-lowering response to simvastatin in Chinese diabetic patients

OBJECTIVE

To investigate whether ScrF I polymorphism in the 2nd intron of the HMG-COA reductase gene (HMGCR) influences serum lipid levels and whether this polymorphism affects the efficiency of the cholesterol lowering HMG-CoA reductase inhibitor, simvastatin.

METHODS

One hundred sixty-eight patients with type 2 diabetes mellitus (T2DM) prospectively received simvastatin as a single-agent therapy (20mg day-1 p.o.) for 12 weeks. Serum lipid levels were determined before and after simvastatin treatment. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Subjects with the AA homozygotes had significantly higher serum very low-density lipoprotein cholesterol (VLDL-C) levels than those with the aa homozygotes. In addition, in 168 patients with T2DM who took 20mg simvastatin, the VLDL-C lowering effect by simvastatin in subjects with the aa homozygotes was significantly lower than in those with the Aa heterozygotes and AA homozygotes.

CONCLUSIONS

Simvastatin treatment significantly decreased plasma lipids in all patients (P<0.01). Importantly, we demonstrate that ScrF I polymorphism of the HMGCR gene in patients with T2DM groups is associated with significant elevation of serum VLDL-C levels. Subjects with the AA homozygotes had significantly higher serum high VLDL-C levels than those with the Aa heterozygotes and aa homozygotes (AA: 2.18+/-0.51; Aa: 2.04+/-0.59, aa: 1.86+/-0.43, P<0.05 for comparison among three genotypes and P<0.01 for difference between AA and aa). Furthermore, this polymorphism tends to show an enhanced response to an HMG-CoA reductase inhibitor in terms of the cholesterol-lowering effect. In 168 patients with T2DM who took 20mg simvastatin, the VLDL-C lowering effect by simvastatin in subjects with the AA homozygotes was significantly lower than in those with the Aa heterozygotes and aa homozygotes (the reduction in serum VLDL-C levels; 37.03+/-5.67 versus 28.97+/-4.96, P<0.01; 34.62+/-5.87 versus 28.97+/-4.96, P<0.05). These results suggest that the HMGCR gene may serve as a modifier gene for hypercholesterolemia in Chinese diabetic patients.

Effect of atorvastatin upon platelet activation in hypercholesterolemia, evaluated by flow cytometry

Hyperlipidemia is a well established risk factor for cardiovascular disease and atherothrombotic events, in which platelet activation also plays a significant role. However, very few studies have addressed platelet activation in hypercholesterolemia, the potential effect of lipid lowering drugs upon platelet hyperfunction, and the question of whether changes in the latter are correlated to normalization of plasma lipids. This study used whole blood flow cytometry to assess in vivo and in vitro platelet activation in a group of 33 patients with hypercholesterolemia, and also the ex vivo effect of atorvastatin (20 mg/day) upon such activation. A control group of 40 normolipidemic volunteers matched in terms of age, sex and added risk factors to the patient group was used. The results showed that hypercholesterolemic patients had in vivo a significantly greater percentage of GPIIb/IIIa- and phosphatidylserine-positive platelets compared with the control group (4.62+/-3.51% and 2.58+/-1.19% versus 2.73+/-1.08% and 1.54+/-0.68%, respectively). In vitro response of CD62 expression to thrombin was also greater in the patients than in the controls (92.51+/-6.00% versus 89.63+/-10.72%, p<0.05). Atorvastatin therapy normalized platelet hyperfunction in the patients studied and reduced GPIIb/IIIa response to ADP (from 82.65+/-6.43% to 75.84+/-4.89%, p<0.01). A significant correlation can be seen between such normalization and the decrease in plasma levels of total and LDL cholesterol.

Lipid-lowering therapies in development

Lipid lowering is established as a proven intervention to reduce atherosclerosis and its complications. This article summarises novel developments in the lipid-altering therapies under development, including combination therapies, squalene synthase inhibitors, microsomal transfer protein inhibitors, acyl-cholesterol acyl transferase inhibitors, cholesterol ester transfer protein antagonists, peroxisome proliferator-activated receptor agonists, high-density lipoprotein-derived peptides and inflammation inhibitors, which have at least reached trials in animal models. Lipid-altering drugs are likely to to be a fast-developing area for novel treatments as possible synergies exist between new and established compounds for the treatment of atherosclerosis. New agents will have to show significant advantage in tolerability or efficacy over existing agents and have the potential to be used in combination therapy as is well established for bile acid sequestrants, nicotinic acid or fibrates and statins. Any new drugs will also have to be assessed in clinical end-point trials against current compounds with proven outcome benefits.

Molecular docking of the highly hypolipidemic agent α-asarone with the catalytic portion of HMG-CoA reductase

Docking experiments using a number of published crystal structures of HMG-CoA reductase with the potent hypocholesterolemic agent alpha-asarone are described. The results indicate that alpha-asarone binds in the enzyme's active site. The methoxy groups play a key role in the binding and probably also in its biological activity, as shown by extensive SAR studies reported for analogues of alpha-asarone. The docking results will be valuable for the structure-based design of novel hypolipidemic agents.

Modulatory effects of HMG-CoA reductase inhibitors in diabetic microangiopathy

3-hydroxy-3-methyl-glutaryl CoA (HMG-CoA) reductase inhibitors or statins are competitive inhibitors of the rate-limiting enzyme in cholesterol biosynthesis. Several large landmark clinical studies have shown a marked reduction of cardiovascular mortality and morbidity in patients treated with statins. Because of the strong association between serum cholesterol levels and coronary artery disease, investigators initially assumed that the predominant beneficial effects of statins result from their lipid-lowering properties. However, more recent observations have suggested that the clinical benefits of statins may be in part independent of their cholesterol-lowering effects. The pleiotropic or cholesterol-independent effects of statins might result from preventing the production of isoprenoids. Isoprenoids serve as important lipid attachments for the post-translational modification of a variety of proteins such as small GTP binding proteins implicated in intracellular signaling. The list of different pleiotropic effects of statins is still growing and, among others, includes the modulatory effects of statins on endothelial function, oxidative stress, coagulation, plaque stability, and inflammation. The pleiotropic effects of statins represent an area of great interest in prevention and therapy of cardiovascular and other chronic diseases. An area of particular interest is the potential beneficial effects of statins in diabetes and its micro/macrovascular complications. This review summarizes our current understanding of the pleiotropic effects of statins in diabetes and the modulatory effects of statins in various pathobiological pathways involved in diabetes and its complications.

Alpha-asarone inhibits HMG-CoA reductase, lowers serum LDL-cholesterol levels and reduces biliary CSI in hypercholesterolemic rats

Our results showed that alpha-asarone was an inhibitor of hepatic HMG-CoA reductase and that the administration of alpha-asarone at 80 mg/kg body wt. for 8 days decreased serum cholesterol by 38% (p < 0.001) in hypercholesterolemic rats. This alpha-asarone treatment affected mainly the serum LDL-cholesterol levels, leaving serum HDL-cholesterol lipoproteins unaffected, with a consequent decrease of 74% in the LDL/HDL ratio. In addition, alpha-asarone especially stimulated bile flow in hypercholesterolemic rats (60%), increasing the secretion of bile salts, phospholipids and bile cholesterol. The drug also reduced the cholesterol levels of gallbladder bile, whereas the concentration of phospholipids and bile salts increased only slightly, leading to a decrease in the cholesterol saturation index (CSI) of bile in the hypercholesterolemic rats. This CSI decrease and the increase in bile flow induced by alpha-asarone may account for the cholelitholytic effect of alpha-asarone. It seems that alpha-asarone induced clearance of cholesterol from the bloodstream and that the excess of hepatic cholesterol provided by LDL-cholesterol is diverted to bile sterol secretion via a bile choleresis process. The inhibition of HMG-CoA reductase and the increase in bile flow induced by alpha-asarone, as well as the decrease in the CSI, could then explain the hypocholesterolemic and cholelitholytic effects of alpha-asarone.