Prevention of fluvastatin-induced toxicity, mortality, and cardiac myopathy in pregnant rats by mevalonic acid supplementation

Interindividual variability in statin pharmacokinetics and effects of drug transporters

INTRODUCTION

Statins are HMG-CoA reductase inhibitors that primarily lower plasma cholesterol levels. It has been suggested that the myotoxic response is a direct result of hydroxymethylglutaryl-CoA reductase inhibition and dose-dependent. Therefore, an accurate understanding of the combination of drugs that inhibit statin metabolism and factors that cause interindividual variability in the pharmacokinetics of statin is important to avoid serious side effects of statins. Relevant articles included in this review were identified through a PubMed search (through May 2023).

AREAS COVERED

This review provides an overview of hepatic and intestinal metabolism of statins, followed by a discussion of drug-drug interactions and interindividual variables that influence statin pharmacokinetics: gut bacteria, disease, and pharmacokinetics-related genetic polymorphisms.

EXPERT OPINION

Drug-drug interactions have a strong influence on statin pharmacokinetics, and gut microbiota, disease, and genetic polymorphisms all contribute significantly to interindividual variation in statin pharmacokinetics. Individual optimization of statin treatment requires studies that consider the progression of the disease and associated changes in concomitant medications.

Pravastatin for Preventing and Treating Preeclampsia: A Systematic Review

Importance

We have performed a systematic search to summarize the role of statins for preventing and treating severe preeclampsia.

Objective

The aim of this study was to examine whether pravastatin is a useful and safe alternative for treating preeclampsia during pregnancy.

Evidence Acquisition

A systematic MEDLINE (PubMed) search was performed (1979 to June 2017), which was restricted to articles published in English, using the relevant key words of "statins," "pregnancy," "preeclampsia," "obstetrical antiphospholipid syndrome," and "teratogenicity."

Results

The initial search provided 296 articles. Finally, 146 articles were related to the use of statins during pregnancy, regarding their effect on the fetus and the treatment of preeclampsia. Ten studies were related to in vitro studies, 25 in animals, and 24 in humans (13 case report series and 11 cohort studies). We found 84 studies on reviews of such guidelines on cardiovascular disease (35 studies), use of statins in the antiphospholipid syndrome (25 studies), statin's specific use during pregnancy (13 studies), or preeclampsia treatment (11 studies).

Conclusions

Although the studies are of poor quality, the rate of major congenital abnormalities in the newborn exposed to statins during pregnancy is no higher than the expected when compared with overall risk population. The review shows a potential beneficial role of statins in preventing and treating severe preeclampsia that needs to be evaluated through well-designed clinical trials.

Relevance

This update could influence positively the clinical practice, giving an alternative therapy for clinicians who treat preeclampsia, particularly in severe cases.

The Toxicology of HMG—CoA Reductase Inhibitors: Prediction of Human Risk

The discovery that 3-hydroxy-3-methyglutaryl coenzyme A reductase was a rate-determining step in the biosynthesis of cholesterol led to the discovery of inhibitors of this enzyme. To support the development of these agents (statins) as potential hypocholesterolemic drugs, a variety of preclinical studies were conducted in several animal species. Not unexpectedly due to the central role played by mevalonic acid and its products including cholesterol in development and maintenance of cellular homeostasis, administration of high dosage levels of these agents led to the expression of a broad variety of adverse effects in many different tissues. Using the tools of toxicologic pathology and classical risk assessment, these varied toxicities were evaluated by many groups relative to the conditions of use in human therapy and a perspective was developed on potential human risk. These approaches of mechanism-based risk assessment predicted that most of the adverse effects observed in animals would not be seen under conditions of human use and supported the successful introduction of one of the most important classes of human medicines.

Drug-drug interactions that interfere with statin metabolism

INTRODUCTION

Lipid-lowering drugs, especially hydroxymethylglutaryl-CoA reductase inhibitors (statins), are widely used in the treatment and prevention of atherosclerotic diseases. The benefits of statins are well documented. However, myotoxic side effects, which can sometimes be severe, including myopathy or rhabdomyolysis, have been associated with the use of statins. In some cases, this toxicity is associated with pharmacokinetic alterations. Potent inhibitors of CYP 3A4 significantly increase plasma concentrations of the active forms of simvastatin, lovastatin and atorvastatin. Fluvastatin is metabolized by CYP2C9, while pravastatin, rosuvastatin and pitavastatin are not susceptible to inhibition by any CYP.

AREAS COVERED

This review discusses the pharmacokinetic aspects of the drug-drug interaction with statins and genetic polymorphisms in CYPs, which are involved in the metabolism of statins, and highlights the importance of establishing a system utilizing electronic medical information practically to avoid adverse drug reactions.

EXPERT OPINION

An understanding of the mechanisms underlying statin interactions will help to minimize drug interactions and develop statins that are less prone to adverse interactions. Quantitatively analyzed information for the low-density lipoprotein cholesterol lowering effects of statin based on electronic medical records may be useful for avoiding the adverse effect of statins.

Safety of fluvastatin in patients undergoing high-risk non-cardiac surgery

IMPORTANCE OF THE FIELD

In patients undergoing vascular surgery there is a high incidence of adverse cardiac events, due to sudden coronary plaque rupture. The non-lipid lowering or pleiotropic effects of statins can help reduce adverse cardiovascular events associated with vascular surgery.

AREAS COVERED IN THIS REVIEW

The evidence for perioperative use of fluvastatin, as well as other statins, in high-risk surgery patients is summarized in this review. Data on pharmacokinetics and metabolism is presented, together with considerations on possible drug interactions in the perioperative period.

WHAT THE READER WILL GAIN

The reader will gain a comprehensive understanding of the existing safety and efficacy data for fluvastatin and other statins in the perioperative period. The practical considerations of perioperative fluvastatin therapy will be presented, including potential side-effects and management of the early non-oral phase immediately post surgery. Finally, advice on when to initiate therapy and safety recommendations are offered.

TAKE HOME MESSAGE

In patients scheduled for high-risk vascular surgery, fluvastatin improves postoperative outcome, reducing the incidence of myocardial damage by approximately 50% in the first 30 days following vascular surgery. In comparison with placebo, fluvastatin was not associated with a rise in liver enzymes or creatine kinase levels. To bridge the non-oral phase, an extended-release formula is recommended.

Statin-induced myopathy in the rat: relationship between systemic exposure, muscle exposure and myopathy

Rare instances of myopathy are associated with all statins, but cerivastatin was withdrawn from clinical use due to a greater incidence of myopathy. The mechanism of statin-induced myopathy with respect to tissue disposition was investigated by measuring the systemic, hepatic, and skeletal muscle exposure of cerivastatin, rosuvastatin, and simvastatin in rats before and after muscle damage. The development of myopathy was not associated with the accumulation of statins in skeletal muscle. For each statin exposure was equivalent in muscles irrespective of their fibre-type sensitivity to myopathy. The low amount of each statin in skeletal muscle relative to the liver does not support a significant role for transporters in the disposition of statins in skeletal muscle. Finally, the concentration of cerivastatin necessary to cause necrosis in skeletal muscle was considerably lower than rosuvastatin or simvastatin, supporting the concept cerivastatin is intrinsically more myotoxic than other statins.

Atorvastatin has cardiac safety at intensive cholesterol-reducing protocols for long term, yet its cancer-treatment doses with chemotherapy may cause cardiomyopathy even under coenzyme-Q10 protection

Statins provide strong clinical benefits via reducing stroke deaths, and they are also considered for tumor reduction and chemo-sensitization. High dose atorvastatin in adults (80 mg daily, approx. 1 mg/kg) is proven to afford greater protection against cardiac deaths than does a standard lipid-lowering dose in coronary syndrome. For cancer trials, mega doses up to 30 mg/kg have been used for short term treatments but neither a high nor a mega-dose of atorvastatin has been tested for long term cardiac safety. This may be of special concern, since some animal studies showed deleterious effects of statins on cardiac tissue, which may be related with coenzymeQ (CoQ) depletion. We performed an electron microscopic analysis of rat hearts after low, high-or mega-dose atorvastatin therapy and with or without MNU (methyl-nitrosourea)-stress. MNU + daily high dose atorvastatin treatment for 13 months did not produce severe cardiac toxicity with CoQ. However, at mega doses (30 mg/kg) and with MNU, mitochondrial damage and myofibrillary disintegration was obvious. Strong proliferation of mitochondria under high dose atorvastatin therapy with CoQ may explain the lack of cardiotoxicity; and this finding seems to parallel recent data that statins induce HNF-4 and PPAR-alpha, both responsible for mitochondria-proliferation. Employment of statins for tumor chemo-sensitization at high-dosage and for long term treatments may require strategies to direct the mevalonate-entry differentially into cardiac and tumor cells and to develop a protocol analogous to folic acid salvage of methotrexate toxicity.

Perinatal/postnatal study of D-003, a mixture of long-chain fatty acids, in rats

D-003 is a mixture of long-chain fatty acids isolated and purified from sugar cane wax with cholesterol-lowering and antiplatelet effects. In order to further characterize the developmental toxicity during the treatment period from late gestation up to weaning of the offspring, pregnant females received 0 (control), 500, and 1,000 mg/kg/day D-003 daily by oral gavage beginning at day 15 of pregnancy and through gestation until day 21 postpartum. Maternal clinical signs, body weight, and food intake were measured at regular intervals during gestation and lactation. Live pups were weighed, sexed, and examined for developmental signs. One female and male of each litter were randomly selected to evaluate the reproductive potential. There were no spontaneous or dose-related maternal deaths during the course of this study. The general health and behavioral condition of offspring was good in all groups. No significant differences among groups were found in comparisons of litter size, survival through the weaning period, sex ratio, and male and female weights. This peri- and postnatal study conducted with D-003 in rats indicated that treatment of the dam during late gestation and lactation did not show adversely effects on reproductive performance or fetal development over two generations.

Colesevelam hydrochloride does not cause maternal or fetal toxicity in rats and rabbits

WelChol (colesevelam hydrochloride), a bile acid sequestrant for the treatment of hypercholesterolemia, was evaluated for adverse effects on reproduction and fetal development using standard preclinical tests. During gestation, Sprague-Dawley rats used in the developmental toxicity study received feed, feed/control article or feed plus 300, 1,000 or 3,000 mg/kg/day colesevelam whereas rats in the pre- and postnatal toxicity study received vehicle or 100, 300 or 1,000 mg/kg/day colesevelam via gavage. New Zealand white rabbits received control or 100, 500 or 1,000 mg/kg/day colesevelam via gavage. No deaths, premature deliveries or gross pathologic lesions were observed up to gestation day (GD) 20 for rats and GD 28 for rabbits. No significant differences in the number of pregnant animals, average litter size, percentage of viable fetuses, fetal body weights, number of corpora lutea, fetal viability, or gross malformations were observed versus controls. Pre- and postnatal effects were assessed in pregnant rats receiving 100, 300 or 1,000 mg/kg/day colesevelam from GD 6 to postpartum day 22. Gestation, parturition and lactation in F(0) generation dams were similar between treatment and control groups. Colesevelam did not affect physical or neurological development or induce gross pathological changes in F(1) generation rats. Colesevelam does not produce developmental toxicity in rats or rabbits, nor does it exhibit pre- or postnatal toxicity in rats at the tested doses.

Neonatal mortality from in utero exposure to perfluorooctanesulfonate (PFOS) in Sprague-Dawley rats: dose-response, and biochemical and pharamacokinetic parameters

Perfluorooctanesulfonate (PFOS) is a widely distributed, environmentally persistent acid found at low levels in human, wildlife, and environmental media samples. Neonatal mortality has been observed following PFOS exposure in a two-generation reproduction study in rats and after dosing pregnant rats and mice during gestation. Objectives of the current study were to better define the dose-response curve for neonatal mortality in rat pups born to PFOS-exposed dams and to investigate biochemical and pharmacokinetic parameters potentially related to the etiology of effects observed in neonatal rat pups. In the current study, additional doses of 0.8, 1.0, 1.2, and 2.0 mg/kg/day were included with original doses used in the two-generation study of 0.4 and 1.6 mg/kg/day in order to obtain data in the critical range of the dose-response curve. Biochemical parameters investigated in dams and litters included: (1) serum lipids, glucose, mevalonic acid, and thyroid hormones; (2) milk cholesterol; and (3) liver lipids. Pharmacokinetic parameters investigated included the interrelationship of administered oral dose of PFOS to maternal body burden of PFOS and the transfer of maternal body burden to the fetus in utero and pup during lactation, as these factors may affect neonatal toxicity. Dosing of dams occurred for 6 weeks prior to mating with untreated breeder males, through confirmed mating, gestation, and day four of lactation. Dose levels for the dose-response and etiological investigation were 0.0, 0.4, 0.8, 1.0, 1.2, 1.6, and 2.0 mg/kg/day PFOS. Statistically significant decreases in gestation length were observed in the 0.8 mg/kg and higher dose groups. Decreases in viability through lactation day 5 were observed in the 0.8 mg/kg and higher dose groups, becoming statistically significant in the 1.6 and 2.0 mg/kg dose groups. Reduced neonatal survival did not appear to be the result of reductions in lipids, glucose utilization, or thyroid hormones. The endpoints of gestation length and decreased viability were positively correlated, suggesting that late-stage fetal development may be affected in pups exposed to PFOS in utero and may contribute to the observed mortality. Benchmark dose (BMD) estimates for decreased gestation length, birth weight, pup weight on lactation day 5, pup weight gain through lactation day 5, and viability resulted in values ranging from 0.27 to 0.89mg/kg/day for the lower 95% confidence limit of the BMD5 (BMDL5). Results of analyses for PFOS in biological matrices indicate a linear proportionality of mean serum PFOS concentration to maternal administered dose prior to mating and through the first two trimesters of gestation. However, at 21 days of gestation, mean serum PFOS concentrations were notably reduced from values measured earlier in gestation. Urinary and fecal elimination was low as expected from prior observations in adult rats. Significant transfer of PFOS from dam to fetus in utero was confirmed, and results suggest that dam and corresponding fetal body burdens, as indicated by serum and liver PFOS levels, correlate with neonatal survival.

Mechanistic and epidemiologic considerations in the evaluation of adverse birth outcomes following gestational exposure to statins

The cholesterol-lowering "statin" drugs are contraindicated in pregnancy, but few data exist on their safety in human gestation. We reviewed case reports for patterns suggesting drug-related effects on prenatal development and considered a variety of mechanisms by which such effects, if confirmed, might occur. This uncontrolled case series included all FDA reports of statin exposures during gestation, as well as others from the literature and from manufacturers. Exposures and outcomes were reviewed and were tabulated by individual drug. Age-specific rates of exposure to each drug among women of child-bearing age were estimated. Of 214 ascertained pregnancy exposures, 70 evaluable reports remained after excluding uninformative cases. Among 31 adverse outcomes were 22 cases with structural defects, 4 cases of intrauterine growth restriction, and 5 cases of fetal demise. There were two principal categories of recurrent structural defects: cerivastatin and lovastatin were associated with four reports of severe midline CNS defects; simvastatin, lovastatin, and atorvastatin were all associated with reports of limb deficiencies, including two similar complex lower limb defects reported following simvastatin exposure. There were also two cases of VACTERL association among the limb deficiency cases. All adverse outcomes were reported following exposure to cerivastatin, simvastatin, lovastatin, or atorvastatin, which are lipophilic and equilibrate between maternal and embryonic compartments. None were reported following exposure to pravastatin, which is minimally present in the embryo. Statins reaching the embryo may down-regulate biosynthesis of cholesterol as well as many important metabolic intermediates, and may have secondary effects on sterol-dependent morphogens such as Sonic Hedgehog. The reported cases display patterns consistent with dysfunction of cholesterol biosynthesis and Sonic Hedgehog activity. Controlled studies are needed to investigate the teratogenicity of individual drugs in this class.

The role of maternal toxicity in lovastatin-induced developmental toxicity

The role of maternal toxicity in lovastatin-induced developmental toxicity in rats was examined in a series of studies. The first study administered lovastatin at 100, 200, 400, or 800 mg/kg/day (mkd) orally to mated rats from Gestation Day (GD) 6 through 20. Maternal toxicity was observed as transient dose-related body weight losses at the initiation of dosing; there were also deaths and/or morbidity at 400 and 800 mkd. These toxicities occurred in conjunction with forestomach lesions. Mean fetal weights were decreased in all groups (-5 to -16%), and the incidence of skeletal malformations, variations, and incomplete ossifications was increased. The 2 highest doses produced the most severe maternal and developmental effects. Using the same dosages, the second study avoided gestational maternal weight losses and morbidity by starting treatment 14 days before mating with dosing continued to GD 20. There were transient dose-related body weight losses after the start of dosing and deaths in the 400- and 800-mkd groups; however, there was no evidence of maternal toxicity during gestation. Developmental toxicity was evident only as slight, but generally significant (p< or =0.05) decreases in mean fetal weights in groups given > or =200 mkd (-2 to -5%). Significantly, no skeletal abnormalities were observed. A third study administered the pharmacologically active metabolite of lovastatin subcutaneously at dose levels that matched oral maternal drug exposures. In the high-dose group, maternal weight gain and mean fetal weight were slightly decreased but there were no treatment-related skeletal abnormalities. Finally, a series of toxicokinetic studies assessed whether the 2 different developmental toxicity profiles were due to differences in drug exposure between the developmentally toxic and non-toxic dosing regimes. The data showed that groups with no skeletal abnormalities had maternal and embryonic/fetal drug concentrations similar to or even greater than the groups with fetal abnormalities. These results indicate that fetal skeletal abnormalities observed at lovastatin dose levels > or =100 mkd are not due to a direct teratogenic effect, but are the result of excessive maternal toxicity, which most likely involves a nutritional deficiency associated with forestomach lesions and reduced maternal food intake.

Early embryonic lethality caused by targeted disruption of the 3-hydroxy-3-methylglutaryl-CoA reductase gene

The endoplasmic reticulum (ER) enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, which converts HMG-CoA to mevalonate, catalyzes the ratelimiting step in cholesterol biosynthesis. Because this mevalonate pathway also produces several non-sterol isoprenoid compounds, the level of HMG-CoA reductase activity may coordinate many cellular processes and functions. We used gene targeting to knock out the mouse HMG-CoA reductase gene. The heterozygous mutant mice (Hmgcr+/-) appeared normal in their development and gross anatomy and were fertile. Although HMG-CoA reductase activities were reduced in Hmgcr+/- embryonic fibroblasts, the enzyme activities and cholesterol biosynthesis remained unaffected in the liver from Hmgcr+/- mice, suggesting that the haploid amount of Hmgcr gene is not rate-limiting in the hepatic cholesterol homeostasis. Consistently, plasma lipoprotein profiles were similar between Hmgcr+/- and Hmgcr+/+ mice. In contrast, the embryos homozygous for the Hmgcr mutant allele were recovered at the blastocyst stage, but not at E8.5, indicating that HMG-CoA reductase is crucial for early development of the mouse embryos. The lethal phenotype was not completely rescued by supplementing the dams with mevalonate. Although it has been postulated that a second, peroxisome-specific HMG-CoA reductase could substitute for the ER reductase in vitro, we speculate that the putative peroxisomal reductase gene, if existed, does not fully compensate for the lack of the ER enzyme at least in embryogenesis.

Lipid metabolism in pregnancy and its consequences in the fetus and newborn

During early pregnancy there is an increase in body fat accumulation, associated with both hyperphagia and increased lipogenesis. During late pregnancy there is an accelerated breakdown of fat depots, which plays a key role in fetal development. Besides using placental transferred fatty acids, the fetus benefits from two other products: glycerol and ketone bodies. Although glycerol crosses the placenta in small proportions, it is a preferential substrate for maternal gluconeogenesis, and maternal glucose is quantitatively the main substrate crossing the placenta. Enhanced ketogenesis under fasting conditions and the easy transfer of ketones to the fetus allow maternal ketone bodies to reach the fetus, where they can be used as fuels for oxidative metabolism as well as lipogenic substrates. Although maternal cholesterol is an important source of cholesterol for the fetus during early gestation, its importance becomes minimal during late pregnancy, owing to the high capacity of fetal tissues to synthesize cholesterol. Maternal hypertriglyceridemia is a characteristic feature during pregnancy and corresponds to an accumulation of triglycerides not only in very low-density lipoprotein but also in low- and high-density lipoprotein. Although triglycerides do not cross the placental barrier, the presence of lipoprotein receptors in the placenta, together with lipoprotein lipase, phospholipase A2, and intracellular lipase activities, allows the release to the fetus of polyunsaturated fatty acids transported as triglycerides in maternal plasma lipoproteins. Normal fetal development needs the availability of both essential fatty acids and long chain polyunsaturated fatty acids, and the nutritional status of the mother during gestation has been related to fetal growth. However, excessive intake of certain long chain fatty acids may cause both declines in arachidonic acid and enhanced lipid peroxidation, reducing antioxidant capacity.

Cholesterol metabolism and embryogenesis

Although cholesterol has long been known to be an essential component of cell membranes in vertebrate organisms, recent studies have suggested that cholesterol plays a crucial role in specific processes during embryonic development, including the covalent modification of Hedgehog proteins. Here we review the overlapping developmental phenotypes associated with pharmacologically or genetically induced defects in cholesterol biosynthesis, embryonic cholesterol transport and Hedgehog proteins. Shared aspects of these phenotypes suggest that common mechanisms underlie impaired central nervous system development associated with cholesterol deficiency.

A cholesterol-rich diet causes a greater hypercholesterolemic response in pregnant than in nonpregnant rats and does not modify fetal lipoprotein profile

To determine whether pregnancy modifies the hyperlipidemic response to a cholesterol-rich diet, pregnant and virgin rats were fed a semisynthetic diet supplemented (CRD) or not (CD) with 2% cholesterol and 1% cholic acid and studied at d 20 of treatment and/or gestation. Plasma triglycerides, free fatty acids and glycerol and liver triglycerides were greater in pregnant than in virgin rats fed CRD. The increase in both plasma and liver cholesterol caused by CRD did not differ in the two groups. In rats fed CD, hepatic lipase activity in liver was lower in pregnant than in virgin rats, while in those fed CRD, virgin rats had lower activity than those fed CD. Plasma VLDL-triglycerides were higher and LDL-triglycerides lower in pregnant than in virgin rats fed CD. Among those fed CRD, pregnant rats had a higher triglyceride concentration in VLDL and HDL than virgin rats. Cholesterol concentration was higher in VLDL and IDL and lower in HDL in both groups fed CRD than in those fed CD, while cholesterol level in LDL was higher only in pregnant rats fed CRD than in those fed CD. Whereas placental cholesterol concentration was higher in pregnant rats fed CRD than CD, maternal CRD intake did not modify fetal plasma lipoprotein concentrations, fetal body weight or litter size, indicating a lack of cholesterol transfer by the rat placenta. Results therefore show a greater responsiveness to CRD in pregnant than in virgin rats, and we propose that CRD promotes greater liver VLDL-production and lower LDL removal in pregnant than in virgin rats.