Functional and Structural Insights into Human PPARα/δ/γ Subtype Selectivity of Bezafibrate, Fenofibric Acid, and Pemafibrate.

Among the agonists against three peroxisome proliferator-activated receptor (PPAR) subtypes, those against PPARα (fibrates) and PPARγ (glitazones) are currently used to treat dyslipidemia and type 2 diabetes, respectively, whereas PPARδ agonists are expected to be the next-generation metabolic disease drug. In addition, some dual/pan PPAR agonists are currently being investigated via clinical trials as one of the first curative drugs against nonalcoholic fatty liver disease (NAFLD). Because PPARα/δ/γ share considerable amino acid identity and three-dimensional structures, especially in ligand-binding domains (LBDs), clinically approved fibrates, such as bezafibrate, fenofibric acid, and pemafibrate, could also act on PPARδ/γ when used as anti-NAFLD drugs. Therefore, this study examined their PPARα/δ/γ selectivity using three independent assays-a dual luciferase-based GAL4 transactivation assay for COS-7 cells, time-resolved fluorescence resonance energy transfer-based coactivator recruitment assay, and circular dichroism spectroscopy-based thermostability assay. Although the efficacy and efficiency highly varied between agonists, assay types, and PPAR subtypes, the three fibrates, except fenofibric acid that did not affect PPARδ-mediated transactivation and coactivator recruitment, activated all PPAR subtypes in those assays. Furthermore, we aimed to obtain cocrystal structures of PPARδ/γ-LBD and the three fibrates via X-ray diffraction and versatile crystallization methods, which we recently used to obtain 34 structures of PPARα-LBD cocrystallized with 17 ligands, including the fibrates. We herein reveal five novel high-resolution structures of PPARδ/γ-bezafibrate, PPARγ-fenofibric acid, and PPARδ/γ-pemafibrate, thereby providing the molecular basis for their application beyond dyslipidemia treatment.

Comparative Bioavailability Study of Solid Self-Nanoemulsifying Drug Delivery System of Fenofibric Acid in Healthy Male Subjects.

OBJECTIVE: This study aimed to evaluate the effect of solid self-nanoemulsifying drug delivery system (S-SNEDDS) formation on the bioavailability of fenofibric acid. SUBJECT AND METHODS: Three formulations of fenofibric acid, namely, S-SNEDDS containing medium-chain triglyceride (FS1), S-SNEDDS containing long-chain triglyceride (FS2), and FSt as tablet of innovator product, were used in this study. Bioavailability study was conducted in 12 Indonesian healthy male subjects after a single-dose administration of each formulation with three-way crossover design. Blood samples were collected from 0 to 72 h after drug administration and then analyzed using the high-performance liquid chromatography method. Data were statistically analyzed using the ANOVA and the Wilcoxon signed-rank test using a p value of 0.05. Dissolution test was carried out with USP dissolution apparatus using three medium (pH 1.2, 4.5 and 6.8). RESULTS: The rates of absorption of fenofibric acid from S-SNEDDS FS1 and FS2 were significantly increased about 1.78 and 2.40 times, respectively, relative to FSt. Tmax values of FS1 and FS2 were shorter than FSt, namely, 0.96 ± 0.438 h (FS1), 0.71 ± 0.445 h (FS2), and 1.71 ± 0.840 h (FSt), respectively. Meanwhile, the Cmax and AUC values of FS1, FS2, and FSt were found to be not significantly different with a p value of >0.05. S-SNEDDS formation increased the dissolution rate in acid medium. CONCLUSIONS: S-SNEDDS increased the dissolution rate in acid medium and absorption rate of fenofibric acid but did not increase the extent of fenofibric acid absorption.

Visualizing the Journey of Fenofibrate through the Rat Gastrointestinal Tract by Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging.

Mapping the spatial distribution of a drug throughout the gastrointestinal tract (GIT) after oral ingestion can provide novel insights into the interaction between the drug, the oral drug delivery system, and the GIT. Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) is a molecular imaging technique that can analyze molecules in the cryosections of tissues, determining their localization with a spatial resolution of 10-100 µm. The overall aim of this study was to use MALDI-MSI to visualize the distribution and spatial location of a model prodrug (fenofibrate) through the rat GIT. Furthermore, the distribution and spatial colocalization of taurocholate and phospholipids in the rat GIT in relation to fenofibrate were investigated. Rats were given a fenofibrate suspension of 10 mg/mL by oral gavage. Blood samples were drawn, and the rats were euthanized at three different time points. The GIT was collected and frozen, and MALDI-MSI was applied on cross sections of the stomach and intestine. Fenofibrate was detected by MALDI-MSI throughout the GIT, which also revealed that fenofibrate was hydrolyzed to the active drug fenofibric acid already in the stomach. Furthermore, the presence of lyso-phosphatidylcholine (lyso-PC) and taurocholate was confirmed in the lumen of the small intestine. MALDI-MSI was shown to be a useful qualitative tool for localizing parent prodrugs and active drugs, with a possibility for gaining insight into not only the location for activation but also the role of endogenous molecules in the process.

Real-World Effectiveness of Therapy With Rosuvastatin Combined With Fenofibric Acid in a Sample of Colombian Patients With Mixed Dyslipidemia.

BACKGROUND: Ischemic heart disease is the leading cause of death in the world and is associated with dyslipidemia, high blood pressure, diabetes mellitus, and other factors. OBJECTIVE: To determine the clinical effectiveness on the lipid profile of the rosuvastatin + fenofibric acid combination in Colombian patients with high cardiovascular risk and mixed dyslipidemia. METHODS: Longitudinal observational study in a random sample of patients with a diagnosis of mixed dyslipidemia and moderate, high, or very high cardiovascular risk who were treated with rosuvastatin + fenofibric acid. Anthropometric, clinical, laboratory, comorbidity, and pharmacological variables were identified. Effectiveness on the lipid profile was determined. RESULTS: A total of 386 patients were analyzed. They had a mean age of 60.8 ± 11.4 years, 53.1% were female, and 75.6% had high/very high cardiovascular risk. The initial evaluation showed a mean LDL cholesterol of 138.4 ± 67.1 mg/dL and triglycerides of 679.7 ± 573.6 mg/dL. At the end of follow-up, mean LDL cholesterol was 87.5 ± 41.2 mg/dL (reduced by 43.3%; P < .001), and triglycerides were 243.5 ± 170.5 mg/dL (reduced by 64.2%; P < .001). Only 35.4% (n = 73) of patients with very high risk reached the goal of metabolic control, compared to 61.6% (n = 53) with high risk and 55.4% (n = 46) with moderate risk. Belonging to the very high-risk group was associated with a lower probability of achieving the control goal (OR: 0.32; 95%CI: 0.192-0.539). CONCLUSION: The combination of rosuvastatin + fenofibric acid is an effective option in patients with mixed dyslipidemia and high cardiovascular risk, providing a therapeutic alternative for those conditions that require it.

Fenofibrate-Loaded Biodegradable Nanoparticles for the Treatment of Experimental Diabetic Retinopathy and Neovascular Age-Related Macular Degeneration.

Fenofibrate is a peroxisome proliferator-activated receptor α (PPARα) agonist and has been shown to have therapeutic effects on diabetic retinopathy (DR). However, the effects of fenofibrate through systemic administration are not as potent as desired due to inefficient drug delivery to the retina. The present study aimed to explore the sustained therapeutic effects of fenofibrate-loaded biodegradable nanoparticles (NP) on both DR and neovascular age-related macular degeneration (AMD). Fenofibrate was successfully encapsulated into poly(lactic- co-glycolic acid) (PLGA) NP (Feno-NP), and Feno-NP were optimized by varying polymer composition to achieve high drug loading and prolonged drug release. The Feno-NP made of PLGA 34 kDa demonstrated a drug content of 6% w/w and a sustained drug release up to 60 days in vitro. Feno-NP (PLGA 34 kDa) was selected for following in vivo studies, and one single intravitreal (IVT) injection of Feno-NP into rat eyes with a 30G fine needle maintained sustained fenofibric acid drug level in the eye for more than 60 days. The efficacy of Feno-NP in DR and neovascular AMD was investigated using streptozotocin (STZ)-induced diabetic rats, laser-induced choroidal neovascularization (CNV) rats, and very low-density lipoprotein receptor knockout ( Vldlr -/-) mice. Therapeutic effects of Feno-NP were evaluated by measuring electroretinogram (ERG), retinal vascular leakage, leukostasis, CNV size, and retinal levels of vascular endothelial growth factor (VEGF) and intracellular adhesion molecule-1 (ICAM-1). In diabetic rats, Feno-NP ameliorated retinal dysfunctions, reduced retinal vascular leakage, inhibited retinal leukostasis, and downregulated the overexpression of VEGF and ICAM-1 at 8 weeks after one IVT injection. In addition, Feno-NP reduced retinal vascular leakage and CNV formation in both CNV rats and Vldlr -/- mice. Moreover, no toxicity of Feno-NP or Blank-NP to retinal structure and function was detected. Feno-NP exhibited good physiochemical characteristics and controlled drug release profile, conferring prolonged beneficial effects on DR and neovascular AMD.

Fenofibrate Rescues Diabetes-Related Impairment of Ischemia-Mediated Angiogenesis by PPARα-Independent Modulation of Thioredoxin-Interacting Protein.

Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, reduces lower limb amputations in patients with type 2 diabetes. The mechanism is, however, unknown. In this study, we demonstrate that fenofibrate markedly attenuates diabetes-related impairment of ischemia-mediated angiogenesis. In a murine model of hindlimb ischemia, daily oral fenofibrate treatment restored diabetes-impaired blood flow recovery, foot movement, hindlimb capillary density, vessel diameter, and vascular endothelial growth factor signaling to nondiabetic levels in both wild-type and PPARα-knockout mice, indicating that these fenofibrate effects are largely PPARα independent. In vitro, fenofibric acid (FFA) rescued high glucose-induced (25 mmol/L) impairment of endothelial cell migration, tubulogenesis, and survival in a PPARα-independent manner. Interestingly, fenofibrate in vivo and FFA in vitro reversed high glucose-induced expression of thioredoxin-interacting protein (TXNIP), an exquisitely glucose-inducible gene previously identified as a critical mediator of diabetes-related impairment in neovascularization. Conversely, adenoviral overexpression of TXNIP abrogated the restorative effects of FFA on high glucose-impaired endothelial cell function in vitro, indicating that the effects of FFA are mediated by TXNIP. We conclude that fenofibrate rescues diabetic impairment in ischemia-mediated angiogenesis, in large part, by PPARα-independent regulation of TXNIP. These findings may therefore explain the reduction in amputations seen in patients with diabetes treated with fenofibrate.

Metabolic Alterations Associated with Atorvastatin/Fenofibric Acid Combination in Patients with Atherogenic Dyslipidaemia: A Randomized Trial for Comparison with Escalated-Dose Atorvastatin.

In the current study, the metabolic effects of atorvastatin dose escalation versus atorvastatin/fenofibric acid combination were compared using metabolomics analyses. Men and women with combined hyperlipidaemia were initially prescribed atorvastatin (10 mg, ≥4 weeks). Patients who reached low-density lipoprotein-cholesterol targets, but had triglyceride and high-density lipoprotein-cholesterol levels ≥150 mg/dL and <50 mg/dL, respectively, were randomized to receive atorvastatin 20 mg or atorvastatin 10 mg/fenofibric acid 135 mg for 12 weeks. Metabolite profiling of serum was performed and changes in metabolites after drug treatment in the two groups were compared. Analysis was performed using patients' samples obtained before and after treatment. Of 89 screened patients, 37 who met the inclusion criteria were randomized, and 34 completed the study. Unlike that in the dose-escalation group, distinct clustering of both lipid and aqueous metabolites was observed in the combination group after treatment. Most lipid metabolites of acylglycerols and many of ceramides decreased, while many of sphingomyelins increased in the combination group. Atorvastatin dose escalation modestly decreased lysophosphatidylcholines; however, the effect of combination therapy was variable. Most aqueous metabolites decreased, while L-carnitine remarkably increased in the combination group. In conclusion, the atorvastatin/fenofibric acid combination induced distinct metabolite clustering. Our results provide comprehensive information regarding metabolic changes beyond conventional lipid profiles for this combination therapy.

Unveiling the important roles of coexisting contaminants on photochemical transformations of pharmaceuticals: Fibrate drugs as a case study.

Pharmaceuticals are a group of ubiquitous emerging pollutants, many of which have been shown to undergo efficient photolysis in the environment. Photochemically produced reactive intermediates (PPRIs) sensitized by the pharmaceuticals in sunlit natural waters may induce photodegradation of coexisting compounds. In this study, the roles of coexisting contaminants on the phototransformation of pharmaceuticals were unveiled with the fibrate drugs gemfibrozil (GMF), fenofibrate (FNF), and fenofibric acid (FNFA) as model compounds. GMF undergoes initial concentration dependent photodegradation due to the involvement of singlet oxygen (1O2) initiated self-sensitized photolysis, and undergoes pH dependent photodegradation due to dissociation and hydroxyl radical (OH) generation. The decarboxylated intermediates of GMF and coexisting FNFA significantly accelerated the photodegradation of GMF. The promotional effects of the decarboxylated intermediates are attributed to generation of PPRIs, e.g. 1O2, superoxide (O2-), that subsequently react with GMF. Besides, FNFA can also promote the photodegradation of GMF through the electron transfer reaction from ground state GMF to excited state FNFA, leading to the formation of decarboxylated intermediates. The formed intermediates can subsequently also facilitate GMF photodegradation. The results presented here provided valuable novel insights into the effects of coexisting contaminants on the photodegradation of pharmaceuticals in polluted waters.

Prospective environmental risk assessment of mixtures in wastewater treatment plant effluents - Theoretical considerations and experimental verification.

The aquatic environment is continually exposed to a complex mixture of chemicals, whereby effluents of wastewater treatment plants (WWTPs) are one key source. The aim of the present study was to investigate whether environmental risk assessments (ERAs) addressing individual substances are sufficiently protective for such coincidental mixtures. Based on a literature review of chemicals reported to occur in municipal WWTP effluents and mode-of-action considerations, four different types of mixtures were composed containing human pharmaceuticals, pesticides, and chemicals regulated under REACH. The experimentally determined chronic aquatic toxicity of these mixtures towards primary producers and the invertebrate Daphnia magna could be adequately predicted by the concept of concentration addition, with up to 5-fold overestimation and less than 3-fold underestimation of mixture toxicity. Effluents of a municipal WWTP had no impact on the predictability of mixture toxicity and showed no adverse effects on the test organisms. Predictive ERAs for the individual mixture components based on here derived predicted no effect concentrations (PNECs) and median measured concentrations in WWTP effluents (MCeff) indicated no unacceptable risk for any of the individual chemicals, while MCeff/PNEC summation indicated a possible risk for multi-component mixtures. However, a refined mixture assessment based on the sum of toxic units at species level indicated no unacceptable risks, and allowed for a safety margin of more than factor 10, not taking into account any dilution of WWTP effluents by surface waters. Individual substances, namely climbazole, fenofibric acid and fluoxetine, were dominating the risks of the investigated mixtures, while added risk due to the mixture was found to be low with the risk quotient being increased by less than factor 2. Yet, uncertainty remains regarding chronic mixture toxicity in fish, which was not included in the present study. The number and identity of substances composing environmental mixtures such as WWTP effluents is typically unknown. Therefore, a mixture assessment factor is discussed as an option for a prospective ERA of mixtures of unknown composition.

Anti-inflammatory activity of anti-hyperlipidemic drug, fenofibrate, and its phase-I metabolite fenofibric acid: in silico, in vitro, and in vivo studies.

Fenofibrate, an anti-hyperlipidemic drug and its phase-I biotransformed metabolite fenofibric acid, was studied for COX-1 (PDB ID: 3N8Y) and COX-2 (PDB ID: 1PXX) inhibition potentials in silico and in vitro for their effects on human recombinant COX-2 enzyme isolated from a Baculovirus expression system in sf21 cells (EC 1.14.99.1) using a conventional spectrophotometric assay. Furthermore, the compounds were also screened for their anti-inflammatory potentials in vivo using carrageenan-induced paw oedema method in Wistar rats. The test compounds fenofibric acid, fenofibrate, and the standard drug diclofenac exhibited binding energies of - 9.0, - 7.2, and - 8.0 kcal mol-1, respectively, against COX-2 and - 7.2, - 7.0, and - 6.5 kcal mol-1, respectively, against COX-1. In in vitro studies, both the test compounds inhibited COX-2 enzyme activity. Fenofibric acid showed an IC50 value of 48 nM followed by fenofibrate (82 nM), while diclofenac showed an IC50 value of 58 nM. Furthermore, under in vivo conditions in carrageenan-induced paw oedema rodent model, fenofibric acid exhibited relatively potent anti-inflammatory activity compared with fenofibrate. Hence, we conclude that fenofibric acid and fenofibrate are not only anti-hyperlipidemic but also shows potent anti-inflammatory activity, which may have an additional impact in the treatment of diabetic complications, viz., hyperlipidemia and inflammation leading to atherosclerosis.

The effect of fenofibric acid on the pharmacokinetics and pharmacodynamics of warfarin in rats.

1. Case reports have shown that coadministration of fenofibric acid (FA) could increase bleeding risks of warfarin, but the mechanisms remained unknown. We therefore investigated the pharmacokinetic and pharmacodynamic interaction between warfarin and FA in rats. 2. Rats received warfarin alone (2 mg/kg) or coadministered with FA (100 mg/kg). FA significantly increased the exposure to warfarin, and decreased that to 7-hydroxywarfarin in rats nearly by two-fold, meanwhile increased Cmax and prolonged t1/2 of warfarin. Anticoagulant activity significantly increased, with prothrombin time (PT) up to 199 ± 33 s in coadministered group (approximately ten-fold compared with rats received warfarin alone). Incubation experiments illustrated FA inhibited CYP2C6 and CYP3A1/2 with the IC50 values of 6.98 and 16.14 µM, and inhibited the metabolism of warfarin (Ki value of 2.21 µM). Meanwhile, FA decreased the plasma protein binding of warfarin in vitro. 3. Our data suggested that the altered pharmacokinetics and pharmacodynamics of warfarin in rats was primarily attributed to the inhibition of metabolism. Anticoagulant activity monitoring or warfarin dose lowering needs to be considered when patients are coadministered with FA.

Therapeutic Effects of PPARα Agonist on Ocular Neovascularization in Models Recapitulating Neovascular Age-Related Macular Degeneration.

Purpose: This study was designed to evaluate effects of fenofibric acid (Feno-FA), a peroxisome proliferator-activated receptor-alpha (PPARα) agonist, on ocular neovascularization (NV) in models recapitulating neovascular age-related macular degeneration (AMD), and to explore whether the effects are PPARα dependent. Methods: Laser-induced choroidal NV (CNV) in rats and very low-density lipoprotein receptor knockout (Vldlr-/-) mice received daily intraperitoneal injections of Feno-FA or vehicle. Vascular leakage was examined by fundus fluorescein angiography and permeability assay using Evans blue as tracer. In CNV rats, severity of CNV was evaluated by CNV areas and CNV volume. In Vldlr-/- mice, subretinal NV (SRNV) and intraretinal NV (IRNV) were quantified in choroid flat mount and retina flat mount, respectively. Inflammatory factors were measured using Western blotting and retinal leukostasis assay. Further, Pparα-/- mice and age-matched wild-type (WT) mice were used for laser-induced CNV and treated with Feno-FA to explore the underlying mechanism. Results: Feno-FA significantly reduced vascular leakage in CNV rats and Vldlr-/- mice, reduced CNV volume in laser-induced CNV rats, and suppressed SRNV and IRNV in Vldlr-/- mice. In addition, Feno-FA downregulated the expression of inflammatory factors, including VEGF, TNF-α, and intercellular cell adhesion molecule-1 (ICAM-1), in the eyecups of CNV rats and decreased adherent retinal leukocytes in Vldlr-/- mice. Furthermore, Pparα-/- mice developed more severe CNV compared with WT mice, and PPARα knockout abolished the beneficial effects of Feno-FA on CNV. Conclusions: Feno-FA has therapeutic effects on ocular NV in models recapitulating neovascular AMD through a PPARα-dependent mechanism.

Determination of Fenofibric Acid in Rat Plasma and its Application to a Comparative Pharmacokinetic Study of JW322 and Fenofibrate.

In this study, a sensitive and reliable method for the quantitation of fenofibric acid in rat plasma was developed and validated using high performance liquid chromatography (HPLC). The plasma samples were prepared by deproteinization, and sildenafil was used as an internal standard. Chromatographic separation was achieved using a reversed-phase (C18) column. The mobile phase, 0.02 M ammonium acetate buffer:acetonitrile (35:65, v/v), was run at a flow rate of 1.0 mL/min, and the column eluent was monitored using an ultraviolet detector at 280 nm at room temperature. The retention times of sildenafil (an internal standard), and fenofibric acid were approximately 5.9 and 7.7 min, respectively. The quantitation limit of fenofibric acid in rat plasma was 0.03 µg/mL. Pharmacokinetic parameters of fenofibric acid was evaluated after oral (at doses of 20 mg/kg) administration of JW322 and fenofibrate in rats. After oral administration (20 mg/kg) of JW322, relative bioavailability was approximately 272.8% compared to fenofibrate.

In vitro and in vivo performance of monoacyl phospholipid-based self-emulsifying drug delivery systems.

This study investigates the effect of monoacyl phospholipid incorporation on the in vitro and in vivo performance of self-emulsifying drug delivery systems (SEDDS). Monoacyl phosphatidylcholine (Lipoid S LPC 80 (LPC)) was incorporated into four different fenofibrate (FF)-loaded long-chain SEDDS to investigate the impact of LPC on the emulsion droplet size, extent of digestion, colloidal structure evolution and drug precipitation during in vitro lipolysis simulating human conditions and drug bioavailability in a rat model. The four investigated SEDDS containing long-chain glycerides, polyoxyl 35 castor oil or polyoxyl 8 caprylocaproyl glycerides with or without LPC. In situ synchrotron small/wide-angle X-ray scattering (SAXS/WAXS) was used to simultaneously real-time monitor the kinetics of lamellar phase structure development and FF crystalline precipitation. Adding LPC increased the particle size and polydispersity of the dispersed SEDDS. The two LPC-free SEDDS generated lamellar phase structures (Lα) with d-spacing=4.76nm during digestion. Incorporating LPC into these systems inhibited the formation of lamellar phase structures. The amount of precipitated crystalline FF from the four SEDDS was similar during the first 15min but differed during the last 45min of in vitro digestion. The kinetics of colloidal structure development and FF precipitation was related to the digestion kinetics. The in vivo bioavailability data showed no significant differences between the four SEDDS, which correlates with the in vitro FF precipitation during the first 15min of lipolysis. Thus, the presence of LPC, different emulsion droplet sizes and concentration of lamellar phase structures observed in vitro did not correlate with the FF absorption in rats. The study suggests that later time points of the in vitro lipolysis overestimated FF precipitation in rats because of the high enzyme activity, the lack of gastric and absorption steps, and the low bile salts and phospholipid concentrations of the in vitro model.

Absolute oral bioavailability of fenofibric acid and choline fenofibrate in rats determined by ultra-performance liquid chromatography tandem mass spectrometry.

Choline fenofibrate is the choline salt of fenofibric acid, which releases free fenofibric acid in the gastrointestinal tract. To estimate the absolute oral bioavailability of fenofibric acid and choline fenofibrate, a novel and sensitive UPLC-MS/MS method with liquid-liquid extraction procedure was developed for the determination of fenofibric acid in rat plasma. The separation was achieved on a Phenomenex Kinetex C18 column (50 × 2.1 mm, 2.6 µm) containing 2 mm ammonium acetate-methanol with a gradient elution program. Validations of this method including specificity, sensitivity (limit of quantification, 5 ng/mL), linearity (0.005-10 µg/mL), accuracy (within ±4.3%), precision (intra- and inter-day coefficient of variation <11.3%), recovery (94.9-105.2% for fenofibric acid), matrix effect, stability and dilution, were all within acceptable limits. This method successfully supported the determination of fenofibric acid and choline fenofibrate. The absolute oral bioavailability was 93.4% for choline fenofibrate and 40.0% for fenofibric acid. These results suggested that choline fenofibrate and fenofibric acid had a better in vivo pharmacokinetic behavior than that of fenofibrate. The two new orally administrated pharmaceuticals, fenofibric acid and choline fenofibrate, can be developed as alternatives to fenofibrate.

C/EBP-ß Is Differentially Affected by PPARα Agonists Fenofibric Acid and GW7647, But Does Not Change Apolipoprotein A-I Production During ER-Stress and Inflammation.

Increasing apolipoproteinA-I (apoA-I) production may be anti-atherogenic. Thus, there is a need to identify regulatory factors involved. Transcription of apoA-I involves peroxisome-proliferator-activated-receptor-alpha (PPARα) activation, but endoplasmic reticulum (ER) -stress and inflammation also influence apoA-I production. To unravel why PPARα agonist GW7647 increased apoA-I production compared to PPARα agonist fenofibric acid (FeAc) in human hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (CaCo-2) cells, gene expression profiles were compared. Microarray analyses suggested CCAAT/enhancer-binding-protein-beta (C/EBP-ß) involvement in the FeAc condition. Therefore, C/EBP-ß silencing and isoform-specific overexpression experiments were performed under ER-stressed, inflammatory and non-inflammatory conditions. mRNA expression of C/EBP-ß, ATF3, NF-IL3 and GDF15 were upregulated by FeAc compared to GW7647 in both cell lines, while DDIT3 and DDIT4 mRNA were only upregulated in HepG2 cells. This ER-stress related signature was associated with decreased apoA-I secretion. After ER-stress induction by thapsigargin or FeAc addition, intracellular apoA-I concentrations decreased, while ER-stress marker expression (CHOP, XBP1s, C/EBP-ß) increased. Cytokine addition increased intracellular C/EBP-ß levels and lowered apoA-I concentrations. Although a C/EBP binding place is present in the apoA-I promoter, C/EBP-ß silencing or isoform-specific overexpression did not affect apoA-I production in inflammatory, non-inflammatory and ER-stressed conditions. Therefore, C/EBP-ß is not a target to influence hepatic apoA-I production. J. Cell. Biochem. 118: 754-763, 2017. © 2016 Wiley Periodicals, Inc.

Zerumbone, a Bioactive Sesquiterpene, Ameliorates Diabetes-Induced Retinal Microvascular Damage through Inhibition of Phospho-p38 Mitogen-Activated Protein Kinase and Nuclear Factor-κB Pathways.

Zerumbone ameliorates retinal damage by blocking advanced glycation end products and their receptor system in streptozotocin-diabetic rats. Because of the multiple factors involved in diabetic retinopathy (DR) etiology, the mechanisms of zerumbone that are mainly responsible for its ameliorative effect on DR need to be further clarified. In the present study, zerumbone (20 mg or 40 mg/kg) or fenofibric acid (100 mg/kg) was orally administered to diabetic rats by intragastric gavage once daily for three consecutive months. Zerumbone displayed similar characteristics to fenofibric acid in reducing retinal vascular permeability and leukostasis in diabetic rats. Fundus photographs showed that large retinal vessel diameters were decreased in zerumbone-treated diabetic rats. Zerumbone not only down-regulated the gene expression of retinal angiogenic parameters, but also reduced the expression of inflammatory cytokines and chemokines in the retina of diabetic rats. Moreover, zerumbone reduced the p38 MAPK phosphorylation and abrogated the nuclear translocation of NF-κB p65 in the retina of diabetic rats. In conclusion, treatment of diabetic rats with zerumbone attenuates the severity of retinal inflammation and angiogenesis, via inhibition of p38 MAPK and NF-κB signaling pathways. These benefits of zerumbone for DR appear to be linked to its antihyperglycemic and antihyperlipidemic effects.

Ordered mesoporous silica to enhance the bioavailability of poorly water-soluble drugs: Proof of concept in man.

Formulating poorly water soluble drugs using ordered mesoporous silica materials is an emerging approach to tackle solubility-related bioavailability problems. The current study was conducted to assess the bioavailability-enhancing potential of ordered mesoporous silica in man. In this open-label, randomized, two-way cross-over study, 12 overnight fasted healthy volunteers received a single dose of fenofibrate formulated with ordered mesoporous silica or a marketed product based on micronized fenofibrate. Plasma concentrations of fenofibric acid, the pharmacologically active metabolite of fenofibrate, were monitored up to 96h post-dose. The rate (Cmax/dose increased by 77%; tmax reduced by 0.75h) and extent of absorption (AUC0-24h/dose increased by 54%) of fenofibrate were significantly enhanced following administration of the ordered mesoporous silica based formulation. The results of this study serve as a proof of concept in man for this novel formulation approach.

In vitro metabolism of fenofibric acid by carbonyl reducing enzymes.

Fenofibric acid is a hypolipidemic drug that is used as an active ingredient per se or is administered in the form of fenofibrate that releases fenofibric acid after absorption. The metabolism of fenofibric acid is mediated primarily by glucuronidation. However, the other part of fenofibric acid is excreted as reduced fenofibric acid. Enzymes responsible for the formation of reduced fenofibric acid as well as their subcellular localization have remained unknown until now. We have found that the predominant site of fenofibric acid reduction is the human liver cytosol, whereas liver microsomes reduced fenofibric acid to a lower extent and exhibited a lower affinity for this drug (Km > 1000 µM). Of nine carbonyl-reducing enzymes (CREs) tested, CBR1 exhibited the greatest activity for fenofibric acid reduction (CLint = 85.975 µl/mg protein/min). CBR1 predominantly formed (-)-enantiomers of reduced fenofibric acid similar to liver cytosol and in accordance with the in vivo data. AKR1C1, AKR1C2, AKR1C3 and AKR1B1 were also identified as reductases of fenofibric acid but are expected to play only a minor role in fenofibric acid metabolism.

Comparisons of pharmacokinetics and NO-releasing of nitrofibriate and fenofibrate after oral administration in rats.

Nitrofibriate, a new compound of hypolipidemic, is modified based on fenofibrate. Both of them are used for prevention and treatment of cardiovascular diseases. In this study, an accurate and sensitive analytical method of reversed-phase high-performance liquid chromatography was developed to determine fenofibric acid, which is an active metabolite of both nitrofibriate and fenofibrate in rat plasma. This method was validated and successfully applied to pharmacokinetic study of nitrofibriate and fenofibrate after oral administration. The results suggested that the pharmacokinetic behavior of nitrofibriate followed a nonlinear process, while fenofibrate was linear, demonstrating that the two drugs were different in pharmacokinetic behaviors. Moreover, the effect of fenofibrate and nitrofibriate on releasing NO in rat serum was explored. This study showed that nitrofibriate, as a nitric oxide donor, could slowly release nitric oxide in vivo. This study provided a biopharmaceutical basis for further study of nitrofibriate.