Molecular association model of PPARα and its new specific and efficient ligand, pemafibrate: Structural basis for SPPARMα

How E-, L-, and P-Selectins Bind to sLex and PSGL-1: A Quantification of Critical Residue Interactions

Selectins and their ability to interact with specific ligands are a cornerstone in cell communication. Over the last three decades, a considerable wealth of experimental and molecular modeling insights into their structure and modus operandi were gathered. Nonetheless, explaining the role of individual selectin residues on a quantitative level remained elusive, despite its importance in understanding the structure-function relationship in these molecules and designing their inhibitors. This work explores essential interactions of selectin-ligand binding, employing a multiscale approach that combines molecular dynamics, quantum-chemical calculations, and residue interaction network models. Such an approach successfully reproduces most of the experimental findings. It proves to be helpful, with the potential for becoming an established tool for quantitative predictions of residue contribution to the binding of biomolecular complexes. The results empower us to quantify the importance of particular residues and functional groups in the protein-ligand interface and to pinpoint differences in molecular recognition by the three selectins. We show that mutations in the E-, L-, and P-selectins, e.g., different residues in positions 46, 85, 97, and 107, present a crucial difference in how the ligand is engaged. We assess the role of sulfation of tyrosine residues in PSGL-1 and suggest that TyrSO3- in position 51 interacting with Arg85 in P-selectin is a significant factor in the increased affinity of P-selectin to PSGL-1 compared to E- and L-selectins. We propose an original pharmacophore targeting five essential PSGL-binding sites based on the analysis of the selectin···PSGL-1 interactions.

Design, Synthesis, and Structure-Activity Relationships of Biaryl Anilines as Subtype-Selective PPAR-alpha Agonists

The role of peroxisome proliferator-activated receptor alpha (PPARα) in retinal biology is clarifying, and evidence demonstrates that novel PPARα agonists hold promising therapeutic utility for diseases like diabetic retinopathy and age-related macular degeneration. Herein, we disclose the design and initial structure-activity relationships for a new biaryl aniline PPARα agonistic chemotype. Notably, this series exhibits subtype selectivity for PPARα over other isoforms, a phenomenon postulated to be due to the unique benzoic acid headgroup. This biphenyl aniline series is sensitive to B-ring functionalization but allows isosteric replacement, and provides an opportunity for C-ring extension. From this series, 3g, 6j, and 6d were identified as leads with <90 nM potency in a cell-based luciferase assay cell and exhibited efficacy in various disease-relevant cell contexts, thereby setting the stage for further characterization in more advanced in vitro and in vivo models.

Obesity-induced metabolic imbalance allosterically modulates CtBP2 to inhibit PPAR-alpha transcriptional activity

Maintenance of metabolic homeostasis is secured by metabolite-sensing systems, which can be overwhelmed by constant macronutrient surplus in obesity. Not only the uptake processes but also the consumption of energy substrates determine the cellular metabolic burden. We herein describe a novel transcriptional system in this context comprised of peroxisome proliferator-activated receptor alpha (PPARα), a master regulator for fatty acid oxidation, and C-terminal binding protein 2 (CtBP2), a metabolite-sensing transcriptional co-repressor. CtBP2 interacts with PPARα to repress its activity, and the interaction is enhanced upon binding to malonyl-CoA, a metabolic intermediate increased in tissues in obesity and reported to suppress fatty acid oxidation through inhibition of carnitine palmitoyltransferase 1 (CPT1). In line with our preceding observations that CtBP2 adopts a monomeric configuration upon binding to acyl-CoAs, we determined that mutations in CtBP2 that shift the conformational equilibrium toward monomers increase the interaction between CtBP2 and PPARα. In contrast, metabolic manipulations that reduce malonyl-CoA decreased the formation of the CtBP2/PPARα complex. Consistent with these in vitro findings, we found that the CtBP2/PPARα interaction is accelerated in obese livers while genetic deletion of CtBP2 in the liver causes derepression of PPARα target genes. These findings support our model where CtBP2 exists primarily as a monomer in the metabolic milieu of obesity to repress PPARα, representing a liability in metabolic diseases that can be exploited to develop therapeutic approaches.

Pemafibrate inhibited renal dysfunction and fibrosis in a mouse model of adenine-induced chronic kidney disease

AIMS

Peroxisome proliferator-activated receptor-alpha (PPARα) levels are markedly lower in the kidneys of chronic kidney disease (CKD) patients. Fibrates (PPARα agonists) are therapeutic agents against hypertriglyceridemia and potentially against CKD. However, conventional fibrates are eliminated by renal excretion, limiting their use in patients with impaired renal function. Here, we aimed to evaluate the renal risks associated with conventional fibrates via clinical database analysis and investigate the renoprotective effects of pemafibrate, a novel selective PPARα modulator mainly excreted into the bile.

MAIN METHODS

The risks associated with conventional fibrates (fenofibrate, bezafibrate) to the kidneys were evaluated using the Food and Drug Administration Adverse Event Reporting System. Pemafibrate (1 or 0.3 mg/kg/day) was administered daily using an oral sonde. Its renoprotective effects were examined in unilateral ureteral obstruction (UUO)-induced renal fibrosis model mice (UUO mice) and adenine-induced CKD model mice (CKD mice).

KEY FINDINGS

The ratios of glomerular filtration rate decreased and blood creatinine increased were markedly higher after conventional fibrate use. Pemafibrate administration suppressed increased gene expressions of collagen-I, fibronectin, and interleukin 1 beta (IL-1β) in the kidneys of UUO mice. In CKD mice, it suppressed increased plasma creatinine and blood urea nitrogen levels and decreased red blood cell count, hemoglobin, and hematocrit levels, along with renal fibrosis. Moreover, it inhibited the upregulation of monocyte chemoattractant protein-1, IL-1β, tumor necrosis factor-alpha, and IL-6 in the kidneys of CKD mice.

SIGNIFICANCE

These results demonstrated the renoprotective effects of pemafibrate in CKD mice, confirming its potential as a therapeutic agent for renal disorders.

Efficacy and safety of pemafibrate in patients with chronic kidney disease: A retrospective study

Hypertriglyceridemia and chronic kidney disease (CKD) are known risk factors for cardiovascular disease. However, treatment with statins, which control low-density lipoprotein cholesterol levels, increases the risk of estimated glomerular filtration rate (eGFR) reduction. Although conventional fibrates, such as bezafibrate (Beza-F) and fenofibrate (Feno-F), are the mainstay for hypertriglyceridemia treatment, they may be associated with a risk of increased serum creatinine level and renal dysfunction. Pemafibrate (Pema) is pharmacologically defined as a selective peroxisomal proliferator-activated receptor α modulator which is excreted in bile and not likely to cause renal dysfunction. We evaluated the efficacy and safety of switching from Beza-F or Feno-F to Pema in CKD patients with hypertriglyceridemia. We recruited 47 CKD patients with hypertriglyceridemia who were receiving Beza-F, Feno-F, or eicosapentaenoic acid (EPA) but were switched to Pema from 2018 to 2021. A retrospective analysis of renal function and lipid profiles was performed before and 24 weeks after switching. CKD patients switching from EPA to Pema were used as study control. The effect of Pema on hypertriglyceridemia was equivalent to that of Beza-F or Feno-F. However, after switching to Pema, eGFR showed a marked average improvement of 10.2 mL/min/1.73 m2 (P < .001). Improvement in eGFR and levels of n-acetyl-β-d-glucosaminidase and β-2-microglobulin was observed only in cases of switching from Beza-F or Feno-F but not from EPA. Although Beza-F and Feno-F are useful medications for the treatment of hypertriglyceridemia, these are associated with a high risk of renal dysfunction. We also found that the deterioration in eGFR due to Beza-F or Feno-F is reversible with drug withdrawal and may not increase the risk for long-term renal dysfunction. We suggest that Pema may be an effective and safe treatment for hypertriglyceridemia in CKD patients.

In Combo Studies for the Optimization of 5-Aminoanthranilic Acid Derivatives as Potential Multitarget Drugs for the Management of Metabolic Syndrome

Metabolic syndrome is a set of risk factors that consist of abdominal obesity, arterial hypertension, alterations in the lipid profile, and hyperglycemia. The current therapeutic strategy includes polypharmacy, using three or more drugs to control each syndrome component. However, this approach has drawbacks that could lead to therapeutic failure. Multitarget drugs are molecules with the ability to act on different targets simultaneously and are an attractive alternative for treating complex diseases such as metabolic syndrome. Previously, we identified a triamide derivative of 5-aminoanthranilic acid that exhibited hypoglycemic, hypolipemic, and antihypertensive activities simultaneously. In the present study, we report the synthesis and in combo evaluation of new derivatives of anthranilic acid, intending to identify the primary structural factors that improve the activity over metabolic syndrome-related parameters. We found that substitution on position 5, incorporation of 3,4-dimethoxyphenyl substituents, and having a free carboxylic acid group lead to the in vitro inhibition of HMG-CoA reductase, and simultaneously the diminution of the serum levels of glucose, triglycerides, and cholesterol in a diet-induced in vivo model.

The Importance of Charge Transfer and Solvent Screening in the Interactions of Backbones and Functional Groups in Amino Acid Residues and Nucleotides

Quantum mechanical (QM) calculations at the level of density-functional tight-binding are applied to a protein–DNA complex (PDB: 2o8b) consisting of 3763 atoms, averaging 100 snapshots from molecular dynamics simulations. A detailed comparison of QM and force field (Amber) results is presented. It is shown that, when solvent screening is taken into account, the contributions of the backbones are small, and the binding of nucleotides in the double helix is governed by the base–base interactions. On the other hand, the backbones can make a substantial contribution to the binding of amino acid residues to nucleotides and other residues. The effect of charge transfer on the interactions is also analyzed, revealing that the actual charge of nucleotides and amino acid residues can differ by as much as 6 and 8% from the formal integer charge, respectively. The effect of interactions on topological models (protein -residue networks) is elucidated.

Pemafibrate Prevents Rupture of Angiotensin II-Induced Abdominal Aortic Aneurysms

Background

Abdominal aortic aneurysm (AAA) is a life-threatening disease that lacks effective preventive therapies. This study aimed to evaluate the effect of pemafibrate, a selective peroxisome proliferator-activated receptor alpha (PPARα) agonist, on AAA formation and rupture.

Methods

Experimental AAA was induced by subcutaneous angiotensin II (AngII) infusion in ApoE ^{- / -} mice for 4 weeks. Pemafibrate (0.1 mg/kg/day) was administered orally. Dihydroethidium staining was used to evaluate the reactive oxygen species (ROS).

Results

The size of the AngII-induced AAA did not differ between pemafibrate- and vehicle-treated groups. However, a decreased mortality rate due to AAA rupture was observed in pemafibrate-treated mice. Pemafibrate ameliorated AngII-induced ROS and reduced the mRNA expression of interleukin-6 and tumor necrosis factor-α in the aortic wall. Gelatin zymography analysis demonstrated significant inhibition of matrix metalloproteinase-2 activity by pemafibrate. AngII-induced ROS production in human vascular smooth muscle cells was inhibited by pre-treatment with pemafibrate and was accompanied by an increase in catalase activity. Small interfering RNA-mediated knockdown of catalase or PPARα significantly attenuated the anti-oxidative effect of pemafibrate.

Conclusion

Pemafibrate prevented AAA rupture in a murine model, concomitant with reduced ROS, inflammation, and extracellular matrix degradation in the aortic wall. The protective effect against AAA rupture was partly mediated by the anti-oxidative effect of catalase induced by pemafibrate in the smooth muscle cells.

Management of Mild-to-Moderate Hypertriglyceridemia

OBJECTIVE

Hypertriglyceridemia is highly prevalent globally and its prevalence is rising with international increases in the incidence of obesity and diabetes. This review examines current management and future therapies METHODS: For this review, hypertriglyceridemia is defined as mild-to-moderate triglyceride elevation, a fasting or non-fasting triglyceride level >150 mg/dL and <500 mg/dL. We reviewed scientific studies published over the last 30 years and current professional society recommendations regarding evaluation and treatment of hypertriglyceridemia.

RESULTS

Genetics, lifestyle, and other environmental factors impact triglyceride levels. In adults with mild-to-moderate hypertriglyceridemia, clinicians should routinely assess and treat secondary treatable causes (diet, physical activity, obesity, metabolic syndrome, and reduction or cessation of medications that elevate triglyceride levels). Since atherosclerotic cardiovascular disease (ASCVD) risk is the primary clinical concern, statins are usually first-line treatment. Patients with triglyceride levels between >150 mg/dL and <500 mg/dL whose LDL-C is treated adequately with statins (at "maximally tolerated" doses, per some statements) and have either prior cardiovascular disease or diabetes mellitus plus at least 2 additional cardiovascular disease risk factors should be considered for added icosapent ethyl treatment to further reduce their cardiovascular disease risk. Fibrates, niacin, and other approved agents or agents under development are also reviewed in detail.

CONCLUSION

The treatment paradigm for mild-to-moderate hypertriglyceridemia is changing based on data from recent clinical trials. Recent trials suggest that the addition of icosapent ethyl to background statin therapy may further reduce ASCVD risk in patients with moderate HTG, though a particular TG goal has not been identified.

Fibrates: A Possible Treatment Option for Patients with Abdominal Aortic Aneurysm?

Abdominal aortic aneurysm (AAA) is a life-threatening disease; however, there is no established treatment for patients with AAA. Fibrates are agonists of peroxisome proliferator-activated receptor alpha (PPARα) that are widely used as therapeutic agents to treat patients with hypertriglyceridemia. They can regulate the pathogenesis of AAA in multiple ways, for example, by exerting anti-inflammatory and anti-oxidative effects and suppressing the expression of matrix metalloproteinases. Previously, basic and clinical studies have evaluated the effects of fenofibrate on AAA. In this paper, we summarize the results of these studies and discuss the problems associated with using fenofibrate as a therapeutic agent for patients with AAA. In addition, we discuss a new perspective on the regulation of AAA by PPARα agonists.

Accelerated Barrier Repair in Human Skin Explants Induced with a Plant-Derived PPAR-α Activating Complex via Cooperative Interactions

Background

Peroxisome proliferator-activated receptors (PPARs) govern epidermal lipid synthesis and metabolism. In skin, PPAR activation has been shown to regulate genes responsible for permeability barrier homeostasis, epidermal differentiation, lipid biosynthesis, and inflammation.

Objective

Given the known dermatologic benefits of PPARs, we set out to discover a naturally derived, multi-molecule complex that would be superior to the more commonly formulated conjugated linoleic acids (CLAs). We hypothesized that a complex may be capable of modulating PPAR-α by cooperative or multi-ligand binding interactions to accelerate skin barrier repair.

Methods

To achieve this, we assembled a novel PPAR-α agonist complex, referred to as RFV3, from a combination of small molecules routinely used in Ayurvedic medicine and accepted in cosmetic and topical over-the-counter dermatologic products. We tested RFV3’s potential as a PPAR-α agonist by evaluating its transcriptional response, ligand binding affinity to PPAR-α, gene expression profiles and barrier repair properties in human skin explant models.

Results

We assembled RFV3 by solubilizing two standardized plant extracts in a suitable solvent and induced a significant transcriptional response in PPAR-α luciferase reporter assay. Furthermore, transcriptome profiling of RFV3-treated epidermal substitutes revealed expressed genes consistent with known targets of PPAR-α, including those involved in epidermal barrier repair. In addition, in silico modeling demonstrated differential co-binding affinities of RFV3 to PPAR-α compared with those of the endogenous ligands (CLAs) and a synthetic PPAR-α agonist. Lastly, delipidated skin explant models confirmed accelerated barrier repair activity with significant increases in ceramides, filaggrin and transglutaminase-1 after treatment.

Conclusion

These findings suggest that the RFV3 complex successfully mimics a PPAR-α agonist and induces synthesis of skin barrier lipids and proteins consistent with known PPAR pathways.

Real-world Profile of a Selective Peroxisome Proliferator-activated Receptor α Modulator (SPPARMα) in Japanese Patients with Renal Impairment and Dyslipidemia

Objective Although lowering the low-density lipoprotein cholesterol (LDL-C) levels using statins can reduce cardiovascular risk, 70% of the cardiovascular risk remains despite treatment with statins. Several studies have shown that elevated triglyceride (TG)-rich lipoprotein is the primary therapeutic target for reducing the residual risk. However, conventional treatment with fibrates is frequently associated with adverse drug reactions, especially in patients with chronic kidney disease (CKD), and even with a reduction in TG. Pemafibrate is a novel selective peroxisome proliferator-activated receptor α modulator (SPPARMα) with fewer side effects and greater effectiveness that can overcome these challenges. We aimed to investigate the safety and efficacy of pemafibrate in patients with CKD and herein present a real-world profile of pemafibrate. Methods Between January 2019 and January 2020, 126 consecutive patients with hyperglyceridemia from two institutions (54 patients with CKD; 43%) who received pemafibrate were enrolled in this retrospective observational study. Blood samples were collected before (baseline) and at 24 weeks after commencing pemafibrate therapy. The primary endpoint was a decrease in the serum lipid levels. The secondary endpoints were the incidence of rhabdomyolysis, hepatargy, and an exacerbation of CKD. Results All patients, including 51% of patients who were concurrently taking statins, reported significantly reduced total cholesterol, non-high-density lipoprotein-cholesterol (non-HDL-C), LDL-C, and TG, and increased HDL-C (p<0.05). The subgroup of patients with CKD showed similar results without increased HDL-C. No adverse events were observed in any patients. Conclusion Pemafibrate has a good safety profile and efficacy for treating patients with serum lipid abnormalities, including those with CKD.

pyProGA-A PyMOL plugin for protein residue network analysis

The field of protein residue network (PRN) research has brought several useful methods and techniques for structural analysis of proteins and protein complexes. Many of these are ripe and ready to be used by the proteomics community outside of the PRN specialists. In this paper we present software which collects an ensemble of (network) methods tailored towards the analysis of protein-protein interactions (PPI) and/or interactions of proteins with ligands of other type, e.g. nucleic acids, oligosaccharides etc. In parallel, we propose the use of the network differential analysis as a method to identify residues mediating key interactions between proteins. We use a model system, to show that in combination with other, already published methods, also included in pyProGA, it can be used to make such predictions. Such extended repertoire of methods allows to cross-check predictions with other methods as well, as we show here. In addition, the possibility to construct PRN models from various kinds of input is so far a unique asset of our code. One can use structural data as defined in PDB files and/or from data on residue pair interaction energies, either from force-field parameters or fragment molecular orbital (FMO) calculations. pyProGA is a free open-source software available from https://gitlab.com/Vlado_S/pyproga.

Pemafibrate Protects against Fatty Acid-Induced Nephropathy by Maintaining Renal Fatty Acid Metabolism

As classical agonists for peroxisomal proliferator-activated receptor alpha (PPARα), fibrates activate renal fatty acid metabolism (FAM) and provide renoprotection. However, fibrate prescription is limited in patients with kidney disease, since impaired urinary excretion of the drug causes serious adverse effects. Pemafibrate (PEM), a novel selective PPARα modulator, is mainly excreted in bile, and, thus, may be safe and effective in kidney disease patients. It remains unclear, however, whether PEM actually exhibits renoprotective properties. We investigated this issue using mice with fatty acid overload nephropathy (FAON). PEM (0.5 mg/kg body weight/day) or a vehicle was administered for 20 days to 13-week-old wild-type male mice, which were simultaneously injected with free fatty acid (FFA)-binding bovine serum albumin from day 7 to day 20 to induce FAON. All mice were sacrificed on day 20 for assessment of the renoprotective effect of PEM against FAON. PEM significantly attenuated the histological findings of tubular injury caused by FAON, increased the renal expressions of mRNA and proteins related to FAM, and decreased renal FFA content and oxidative stress. Taken together, PEM exhibits renoprotective effects through the activation and maintenance of renal FAM and represents a promising drug for kidney disease.

Identification of Binding Regions of Bilirubin in the Ligand-Binding Pocket of the Peroxisome Proliferator-Activated Receptor-A (PPARalpha)

Recent work has shown that bilirubin has a hormonal function by binding to the peroxisome proliferator-activated receptor-α (PPARα), a nuclear receptor that drives the transcription of genes to control adiposity. Our previous in silico work predicted three potential amino acids that bilirubin may interact with by hydrogen bonding in the PPARα ligand-binding domain (LBD), which could be responsible for the ligand-induced function. To further reveal the amino acids that bilirubin interacts with in the PPARα LBD, we harnessed bilirubin’s known fluorescent properties when bound to proteins such as albumin. Our work here revealed that bilirubin interacts with threonine 283 (T283) and alanine 333 (A333) for ligand binding. Mutational analysis of T283 and A333 showed significantly reduced bilirubin binding, reductions of 11.4% and 17.0%, respectively. Fenofibrate competitive binding studies for the PPARα LBD showed that bilirubin and fenofibrate possibly interact with different amino acid residues. Furthermore, bilirubin showed no interaction with PPARγ. This is the first study to reveal the amino acids responsible for bilirubin binding in the ligand-binding pocket of PPARα. Our work offers new insight into the mechanistic actions of a well-known molecule, bilirubin, and new fronts into its mechanisms.

Effects of pemafibrate on glucose metabolism markers and liver function tests in patients with hypertriglyceridemia: a pooled analysis of six phase 2 and phase 3 randomized double-blind placebo-controlled clinical trials

Background

Increased risk of cardiovascular events is associated not only with dyslipidemias, but also with abnormalities in glucose metabolism and liver function. This study uses pooled analysis to explore the in-depth effects of pemafibrate, a selective peroxisome proliferator-activated receptor α modulator (SPPARMα) already known to decrease elevated triglycerides, on glucose metabolism and liver function in patients with hypertriglyceridemia.

Methods

We performed a post-hoc analysis of six phase 2 and phase 3 Japanese randomized double-blind placebo-controlled trials that examined the effects of daily pemafibrate 0.1 mg, 0.2 mg, and 0.4 mg on glucose metabolism markers and liver function tests (LFTs). Primary endpoints were changes in glucose metabolism markers and LFTs from baseline after 12 weeks of pemafibrate treatment. All adverse events and adverse drug reactions were recorded as safety endpoints.

Results

The study population was 1253 patients randomized to placebo (n = 298) or pemafibrate 0.1 mg/day (n = 127), 0.2 mg/day (n = 584), or 0.4 mg/day (n = 244). Participant mean age was 54.3 years, 65.4 % had BMI ≥ 25 kg/m², 35.8 % had type 2 diabetes, and 42.6 % had fatty liver. Fasting glucose, fasting insulin, and HOMA-IR decreased significantly in all pemafibrate groups compared to placebo. The greatest decrease was for pemafibrate 0.4 mg/day: least square (LS) mean change from baseline in fasting glucose − 0.25 mmol/L; fasting insulin − 3.31 µU/mL; HOMA-IR − 1.28. ALT, γ-GT, ALP, and total bilirubin decreased significantly at all pemafibrate doses vs. placebo, with the greatest decrease in the pemafibrate 0.4 mg/day group: LS mean change from baseline in ALT − 7.6 U/L; γ-GT − 37.3 U/L; ALP − 84.7 U/L; and total bilirubin − 2.27 µmol/L. Changes in HbA1c and AST did not differ significantly from placebo in any pemafibrate groups in the overall study population. The decreases from baseline in LFTs and glucose metabolism markers except for HbA1c were notable among patients with higher baseline values. FGF21 increased significantly in all pemafibrate groups compared to placebo, with the greatest increase in the pemafibrate 0.4 mg/day group. Adverse event rates were similar in all groups including placebo.

Conclusions

In patients with hypertriglyceridemia, pemafibrate can improve glucose metabolism and liver function, and increase FGF21, without increasing adverse event risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01291-w.

Computational Analysis Reveals a Critical Point Mutation in the N-Terminal Region of the Signaling Lymphocytic Activation Molecule Responsible for the Cross-Species Infection with Canine Distemper Virus

Infection of hosts by morbilliviruses is facilitated by the interaction between viral hemagglutinin (H-protein) and the signaling lymphocytic activation molecule (SLAM). Recently, the functional importance of the n-terminal region of human SLAM as a measles virus receptor was demonstrated. However, the functional roles of this region in the infection process by other morbilliviruses and host range determination remain unknown, partly because this region is highly flexible, which has hampered accurate structure determination of this region by X-ray crystallography. In this study, we analyzed the interaction between the H-protein from canine distemper virus (CDV-H) and SLAMs by a computational chemistry approach. Molecular dynamics simulations and fragment molecular orbital analysis demonstrated that the unique His28 in the N-terminal region of SLAM from Macaca is a key determinant that enables the formation of a stable interaction with CDV-H, providing a basis for CDV infection in Macaca. The computational chemistry approach presented should enable the determination of molecular interactions involving regions of proteins that are difficult to predict from crystal structures because of their high flexibility.

Pemafibrate decreases triglycerides and small, dense LDL, but increases LDL-C depending on baseline triglycerides and LDL-C in type 2 diabetes patients with hypertriglyceridemia: an observational study

Background

Pemafibrate, a selective PPARα modulator, has the beneficial effects on serum triglycerides (TGs) and very low density lipoprotein (VLDL), especially in patients with diabetes mellitus or metabolic syndrome. However, its effect on the low density lipoprotein cholesterol (LDL-C) levels is still undefined. LDL-C increased in some cases together with a decrease in TGs, and the profile of lipids, especially LDL-C, during pemafibrate administration was evaluated.

Methods

Pemafibrate was administered to type 2 diabetes patients with hypertriglyceridemia. Fifty-one type 2 diabetes patients (mean age 62 ± 13 years) with a high rate of hypertension and no renal insufficiency were analyzed. Pemafibrate 0.2 mg (0.1 mg twice daily) was administered, and serum lipids were monitored every 4–8 weeks from 8 weeks before administration to 24 weeks after administration. LDL-C was measured by the direct method. Lipoprotein fractions were measured by electrophoresis (polyacrylamide gel, PAG), and LDL-migration index (LDL-MI) was calculated to estimate small, dense LDL.

Results

Pemafibrate reduced serum TGs, midband and VLDL fractions by PAG. Pemafibrate increased LDL-C levels from baseline by 5.3% (− 3.8–19.1, IQR). Patients were divided into 2 groups: LDL-C increase of > 5.3% (group I, n = 25) and < 5.3% (group NI, n = 26) after pemafibrate. Compared to group NI, group I had lower LDL-C (2.53 [1.96–3.26] vs. 3.36 [3.05–3.72] mmol/L, P = 0.0009), higher TGs (3.71 [2.62–6.69] vs. 3.25 [2.64–3.80] mmol/L), lower LDL by PAG (34.2 [14.5, SD] vs. 46.4% [6.5], P = 0.0011), higher VLDL by PAG (28.2 [10.8] vs. 22.0% [5.2], P = 0.0234), and higher LDL-MI (0.421 [0.391–0.450] vs. 0.354 [0.341–0.396], P < 0.0001) at baseline. Pemafibrate decreased LDL-MI in group I, and the differences between the groups disappeared. These results showed contradictory effects of pemafibrate on LDL-C levels, and these effects were dependent on the baseline levels of LDL-C and TGs.

Conclusions

Pemafibrate significantly reduced TGs, VLDL, midband, and small, dense LDL, but increased LDL-C in diabetes patients with higher baseline TGs and lower baseline LDL-C. Even if pre-dose LDL-C remains in the normal range, pemafibrate improves LDL composition and may reduce cardiovascular disease risk.

Selective Peroxisome Proliferator-Activated Receptor Alpha Modulators (SPPARMα) in the Metabolic Syndrome: Is Pemafibrate Light at the End of the Tunnel?

Purpose of Review

Adoption of poor lifestyles (inactivity and energy-dense diets) has driven the worldwide increase in the metabolic syndrome, type 2 diabetes mellitus and non-alcoholic steatohepatitis (NASH). Of the defining features of the metabolic syndrome, an atherogenic dyslipidaemia characterised by elevated triglycerides (TG) and low plasma concentration of high-density lipoprotein cholesterol is a major driver of risk for atherosclerotic cardiovascular disease. Beyond lifestyle intervention and statins, targeting the nuclear receptor peroxisome proliferator-activated receptor alpha (PPARα) is a therapeutic option. However, current PPARα agonists (fibrates) have limitations, including safety issues and the lack of definitive evidence for cardiovascular benefit. Modulating the ligand structure to enhance binding at the PPARα receptor, with the aim of maximising beneficial effects and minimising adverse effects, underlies the SPPARMα concept.

Recent Findings

This review discusses the history of SPPARM development, latterly focusing on evidence for the first licensed SPPARMα, pemafibrate. Evidence from animal models of hypertriglyceridaemia or NASH, as well as clinical trials in patients with atherogenic dyslipidaemia, are overviewed.

Summary

The available data set the scene for therapeutic application of SPPARMα in the metabolic syndrome, and possibly, NASH. The outstanding question, which has so far eluded fibrates in the setting of current evidence-based therapy including statins, is whether treatment with pemafibrate significantly reduces cardiovascular events in patients with atherogenic dyslipidaemia. The PROMINENT study in patients with type 2 diabetes mellitus and this dyslipidaemia is critical to evaluating this.

Small-Molecule Modulation of PPARs for the Treatment of Prevalent Vascular Retinal Diseases

Vascular-related retinal diseases dramatically impact quality of life and create a substantial burden on the healthcare system. Age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity are leading causes of irreversible blindness. In recent years, the scientific community has made great progress in understanding the pathology of these diseases and recent discoveries have identified promising new treatment strategies. Specifically, compelling biochemical and clinical evidence is arising that small-molecule modulation of peroxisome proliferator-activated receptors (PPARs) represents a promising approach to simultaneously address many of the pathological drivers of these vascular-related retinal diseases. This has excited academic and pharmaceutical researchers towards developing new and potent PPAR ligands. This review highlights recent developments in PPAR ligand discovery and discusses the downstream effects of targeting PPARs as a therapeutic approach to treating retinal vascular diseases.

PPARα Agonist Oral Therapy in Diabetic Retinopathy

Diabetic retinopathy (DR) is an eye condition that develops after chronically poorly-managed diabetes, and is presently the main cause for blindness on a global scale. Current treatments for DR such as laser photocoagulation, topical injection of corticosteroids, intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents and vitreoretinal surgery are only applicable at the late stages of DR and there are possibilities of significant adverse effects. Moreover, the forms of treatment available for DR are highly invasive to the eyes. Safer and more effective pharmacological treatments are required for DR treatment, in particular at an early stage. In this review, we cover recently investigated promising oral pharmacotherapies, the methods of which are safer, easier to use, patient-friendly and pain-free, in clinical studies. We especially focus on peroxisome proliferator-activator receptor alpha (PPARα) agonists in which experimental evidence suggests PPARα activation may be closely related to the attenuation of vascular damages, including lipid-induced toxicity, inflammation, an excess of free radical generation, endothelial dysfunction and angiogenesis. Furthermore, oral administration of selective peroxisome proliferator-activated receptor alpha modulator (SPPARMα) agonists may induce hepatic fibroblast growth factor 21 expression, indirectly resulting in retinal protection in animal studies. Our review will enable more comprehensive approaches for understanding protective roles of PPARα for the prevention of DR development.

Measles Virus Hemagglutinin Protein Establishes a Specific Interaction With the Extreme N-Terminal Region of Human Signaling Lymphocytic Activation Molecule to Enhance Infection

Measles virus (MV) is a human pathogen that is classified in the genus Morbillivirus in the family Paramyxoviridae together with several non-human animal morbilliviruses. They cause severe systemic infections by using signaling lymphocytic activation molecule (SLAM) and poliovirus receptor-like 4 expressed on immune and epithelial cells, respectively, as receptors. The viral hemagglutinin (H) protein is responsible for the receptor-binding. Previously determined structures of MV-H and SLAM complexes revealed a major binding interface between the SLAM V domain and MV-H with four binding components (sites 1–4) in the interface. We studied the MV-H and human SLAM (hSLAM) complex structure in further detail by in silico analyses and determined missing regions or residues in the previously determined complex structures. These analyses showed that, in addition to sites 1–4, MV-H establishes a unique interaction with the extreme N-terminal region (ExNTR) of hSLAM. The first principles calculation-based fragment molecular orbital computation method revealed that methionine at position 29 (hSLAM-Met29) is the key residue for the interaction. hSLAM-Met29 was predicted to establish a CH-π interaction with phenylalanine at position 549 of MV-H (MVH-Phe549). A cell-cell fusion assay showed that the hSLAM-Met29 and MVH-Phe549 interaction is important for hSLAM-dependent MV membrane fusion. Furthermore, Jurkat cell lines expressing hSLAM with or without Met29 and recombinant MV possessing the H protein with or without Phe549 showed that the hSLAM-Met29 and MVH-Phe549 interaction enhanced hSLAM-dependent MV infection by ~10-fold. We speculate that in the evolutionary history of morbilliviruses, this interaction may have contributed to MV adaptation to humans because this interaction is unique for MV and only MV uses hSLAM efficiently among morbilliviruses.

Selective Peroxisome Proliferator-Activated Receptor Alpha Modulators (SPPARMα): New Opportunities to Reduce Residual Cardiovascular Risk in Chronic Kidney Disease?

PURPOSE OF REVIEW

Chronic kidney disease (CKD) poses a major global challenge, which is exacerbated by aging populations and the pandemic of type 2 diabetes mellitus. Much of the escalating burden of CKD is due to cardiovascular complications. Current treatment guidelines for dyslipidemia in CKD prioritize low-density lipoprotein cholesterol management, but still leave a high residual cardiovascular risk. Targeting elevated triglycerides and low plasma high-density lipoprotein cholesterol, a common feature of CKD, could offer additional benefit. There are, however, safety issues with current fibrates (peroxisome proliferator-activated receptor alpha [PPARα] agonists), notably the propensity for elevation in serum creatinine, indicating the need for new approaches.

RECENT FINDINGS

Interactions between the ligand and PPARα receptor influence the specificity and potency of receptor binding, and downstream gene and physiological effects. The peroxisome proliferator-activated receptor alpha modulator (SPPARMα) concept aims to modulate the ligand structure so as to enhance binding at the PPARα receptor, thereby improving the ligand's selectivity, potency, and safety profile. This concept has led to the development of pemafibrate, a novel SPPARMα agent. This review discusses evidence that differentiates pemafibrate from current fibrates, especially the lack of evidence for elevation in serum creatinine or worsening of renal function in high-risk patients, including those with CKD. Differentiation of pemafibrate from current fibrates aims to address unmet clinical needs in CKD. The ongoing PROMINENT study will provide critical information regarding the long-term efficacy and safety of pemafibrate in patients with type 2 diabetes mellitus, including those with CKD, and whether the favorable lipid-modifying profile translates to reduction in residual cardiovascular risk.

Emerging targets and potential therapeutic agents in non-alcoholic fatty liver disease treatment

Nonalcoholic Fatty Liver Disease (NAFLD) is the most common chronic liver disease in the world, which is characterized by liver fat accumulation unrelated to excessive drinking. Indeed, it attracts growing attention and becomes a global health problem. Due to the complexity of the NAFLD pathogenic mechanism, no related drugs were approved by Food and Drug Administration (FDA) till now. However, it is encouraging that a series of candidate drugs have entered the clinical trial stage with expectation to treat NAFLD. In this review, we summarized the main pathways and pathogenic mechanisms of NAFLD, as well as introduced the main potential therapeutic targets and the corresponding compounds involved in metabolism, inflammation and fibrosis. Furthermore, we also discuss the progress of these compounds, such as drug design and optimization, the choice of pharmacological properties and druglikeness, and the analysis of structure-activity relationship. This review offers a medium on future drug design and development, to be beneficial to relevant studies.

Pemafibrate, a New Selective PPARα Modulator: Drug Concept and Its Clinical Applications for Dyslipidemia and Metabolic Diseases

PURPOSE OF REVIEW

Reduction of serum low-density lipoprotein cholesterol (LDL-C) levels by statins, ezetimibe and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors has been shown to significantly reduce cardiovascular events risk. However, fasting and postprandial hypertriglyceridemia as well as reduced high-density lipoprotein cholesterol (HDL-C) remain as residual risk factors of atherosclerotic cardiovascular diseases (ASCVD). To treat patients with hypertriglyceridemia and/or low HDL-C, drugs such as fibrates, nicotinic acids, and n-3 polyunsaturated fatty acids have been used. However, fibrates were demonstrated to cause side effects such as liver dysfunction and increase in creatinine levels, and thus large-scale clinical trials of fibrates have shown negative results for prevention of ASCVD. The failure could be attributed to their low selectivity and potency for binding to peroxisome proliferator-activated receptor (PPAR) α. To resolve these issues, the concept of selective PPARα modulator (SPPARMα) with a superior balance of efficacy and safety has been proposed and pemafibrate (K-877) has been developed.

RECENT FINDINGS

Pemafibrate, one of SPPARMsα, was synthesized by Kowa Company, Ltd. for better efficiency and safety. Clinical trials in Japan have established the superiority of pemafibrate on effects on serum triglycerides (TG) reduction and HDL-C elevation as well safety. Although available fibrates showed worsening of liver and kidney function test values, pemafibrate indicated improved liver function test values and was less likely to increase serum creatinine or decrease estimated glomerular filtration rate (eGFR). Very few drug-drug interactions were observed even when used concomitantly with statins. Furthermore, pemafibrate is metabolized in the liver and excreted into the bile, while many of available fibrates are mainly excreted from the kidney. Therefore, pemafibrate can be used safely even in patients with impaired renal function since there is no significant increase in its blood concentration. A large-scale trial of pemafibrate, PROMINENT, for dyslipidemic patients with type 2 diabetes is ongoing. Pemafibrate is one of novel SPPARMsα and has superior benefit-risk balance compared to conventional fibrates and can be applicable for patients for whom the usage of existing fibrates is difficult such as those who are taking statins or patients with renal dysfunction. In the current review, all the recent data on pemafibrate will be summarized.

Pirfenidone Is an Agonistic Ligand for PPARα and Improves NASH by Activation of SIRT1/LKB1/pAMPK

Nonalcoholic steatohepatitis (NASH) is recognized by hepatic lipid accumulation, inflammation, and fibrosis. No studies have evaluated the prolonged‐release pirfenidone (PR‐PFD) properties on NASH features. The aim of this study is to evaluate how PR‐PFD performs on metabolic functions, and provide insight on a mouse model of human NASH. Male C57BL/6J mice were fed with either normo diet or high‐fat/carbohydrate diet for 16 weeks and a subgroup also fed with PR‐PFD (300 mg/kg/day). An insulin tolerance test was performed at the end of treatment. Histological analysis, determination of serum hormones, adipocytokines measurement, and evaluation of proteins by western blot was performed. Molecular docking, in silico site‐directed mutagenesis, and in vitro experiments using HepG2 cultured cells were performed to validate PR‐PFD binding to peroxisome proliferator–activated receptor alpha (PPAR‐α), activation of PPAR‐α promoter, and sirtuin 1 (SIRT1) protein expression. Compared with the high‐fat group, the PR‐PFD‐treated mice displayed less weight gain, cholesterol, very low density lipoprotein and triglycerides, and showed a significant reduction of hepatic macrosteatosis, inflammation, hepatocyte ballooning, fibrosis, epididymal fat, and total adiposity. PR‐PFD restored levels of insulin, glucagon, adiponectin, and resistin along with improved insulin resistance. Noteworthy, SIRT1–liver kinase B1–phospho‐5′ adenosine monophosphate–activated protein kinase signaling and the PPAR‐α/carnitine O‐palmitoyltransferase 1/acyl‐CoA oxidase 1 pathway were clearly induced in high fat + PR‐PFD mice. In HepG2 cells incubated with palmitate, PR‐PFD induced activation and nuclear translocation of both PPARα and SIRT1, which correlated with increased SIRT1 phosphorylated in serine 47, suggesting a positive feedback loop between the two proteins. These results were confirmed with both synthetic PPAR‐α and SIRT1 activators and inhibitors. Finally, we found that PR‐PFD is a true agonist/ligand for PPAR‐α. Conclusions: PR‐PFD provided an anti‐steatogenic effect and protection for inflammation and fibrosis.

Elucidation of Molecular Mechanism of a Selective PPARα Modulator, Pemafibrate, through Combinational Approaches of X-ray Crystallography, Thermodynamic Analysis, and First-Principle Calculations

The selective PPARα modulator (SPPARMα) is expected to medicate dyslipidemia with minimizing adverse effects. Recently, pemafibrate was screened from the ligand library as an SPPARMα bearing strong potency. Several clinical pieces of evidence have proved the usefulness of pemafibrate as a medication; however, how pemafibrate works as a SPPARMα at the molecular level is not fully known. In this study, we investigate the molecular mechanism behind its novel SPPARMα character through a combination of approaches of X-ray crystallography, isothermal titration calorimetry (ITC), and fragment molecular orbital (FMO) analysis. ITC measurements have indicated that pemafibrate binds more strongly to PPARα than to PPARγ. The crystal structure of PPARα-ligand binding domain (LBD)/pemafibrate/steroid receptor coactivator-1 peptide (SRC1) determined at 3.2 Å resolution indicates that pemafibrate binds to the ligand binding pocket (LBP) of PPARα in a Y-shaped form. The structure also reveals that the conformation of the phenoxyalkyl group in pemafibrate is flexible in the absence of SRC1 coactivator peptide bound to PPARα; this gives a freedom for the phenoxyalkyl group to adopt structural changes induced by the binding of coactivators. FMO calculations have indicated that the accumulation of hydrophobic interactions provided by the residues at the LBP improve the interaction between pemafibrate and PPARα compared with the interaction between fenofibrate and PPARα.

SPPARM alpha: the Lazarus effect

PURPOSE OF REVIEW

Atherogenic dyslipidaemia, characterized by high plasma triglycerides (a surrogate for triglyceride-rich remnant lipoproteins) and low high-density lipoprotein cholesterol (HDL-C), is prevalent in patients with type 2 diabetes mellitus (T2DM) and contributes to a high modifiable residual cardiovascular risk. Fibrates are effective in managing hypertriglyceridaemia but lack consistent cardiovascular benefit in clinical trials and exhibit pharmacokinetic interaction with statins (gemfibrozil) and renal and hepatic safety issues (fenofibrate). The selective peroxisome proliferator-activated receptor alpha modulator (SPPARMα) paradigm offers potential for improving potency, selectivity and the benefit-risk profile.

RECENT FINDINGS

The present review discusses evidence for the novel SPPARMα agonist, pemafibrate. Clinical trials showed robust lowering of triglyceride-rich lipoproteins, elevation in HDL-C and nonlipid beneficial effects including anti-inflammatory activity. There was a favourable safety profile, with no increase in serum creatinine, evident with fenofibrate, and improved renal and hepatic safety. The cardiovascular outcomes study PROMINENT is critical to confirming the SPPARMα concept by validating reduction in residual cardiovascular risk in patients with T2DM and long-term safety.

SUMMARY

SPPARMα offers a new paradigm for reducing residual cardiovascular risk in T2DM. PROMINENT will be critical to differentiating the first SPPARMα, pemafibrate, as a novel therapeutic class distinct from current fibrates.

Pemafibrate Prevents Retinal Pathological Neovascularization by Increasing FGF21 Level in a Murine Oxygen-Induced Retinopathy Model

Large-scale clinical trials, such as the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and the Action to Control Cardiovascular Risk in Diabetes (ACCORD) studies, have shown that the administration of fenofibrate, a peroxisome proliferator-activated receptor alpha (PPARα) agonist, suppresses the progression of diabetic retinopathy. In this paper, we reveal a therapeutic effect of a selective PPARα modulator (SPPARMα), pemafibrate, against pathological angiogenesis in murine models of retinopathy. Oxygen-induced retinopathy (OIR) was induced in C57BL/6J mice by exposure to 85% oxygen from postnatal day eight (P8) for 72 h. Vehicle, pemafibrate or fenofibrate was administrated by oral gavage from P12 to P16 daily. Administration of pemafibrate, but not fenofibrate, significantly reduced pathological angiogenesis in OIR. After oral pemafibrate administration, expression levels of downstream PPARα targets such as acyl-CoA oxidase 1 (Acox1), fatty acid binding protein 4 (Fabp4), and fibroblast growth factor 21 (Fgf21) were significantly increased in the liver but not in the retina. A significant increase in plasma FGF21 and reduced retinal hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (Vegfa) were also observed after this treatment. In an in vitro HIF-luciferase assay, a long-acting FGF21 analogue, but not pemafibrate, suppressed HIF activity. These data indicate that SPPARMα pemafibrate administration may prevent retinal pathological neovascularization by upregulating FGF21 in the liver.

Gene Expression Profiles Induced by a Novel Selective Peroxisome Proliferator-Activated Receptor α Modulator (SPPARMα) Pemafibrate

Pemafibrate is the first clinically-available selective peroxisome proliferator-activated receptor α modulator (SPPARMα) that has been shown to effectively improve hypertriglyceridemia and low high-density lipoprotein cholesterol (HDL-C) levels. Global gene expression analysis reveals that the activation of PPARα by pemafibrate induces fatty acid (FA) uptake, binding, and mitochondrial or peroxisomal oxidation as well as ketogenesis in mouse liver. Pemafibrate most profoundly induces HMGCS2 and PDK4, which regulate the rate-limiting step of ketogenesis and glucose oxidation, respectively, compared to other fatty acid metabolic genes in human hepatocytes. This suggests that PPARα plays a crucial role in nutrient flux in the human liver. Additionally, pemafibrate induces clinically favorable genes, such as ABCA1, FGF21, and VLDLR. Furthermore, pemafibrate shows anti-inflammatory effects in vascular endothelial cells. Pemafibrate is predicted to exhibit beneficial effects in patients with atherogenic dyslipidemia and diabetic microvascular complications.

Efficacy and Safety of Pemafibrate, a Novel Selective Peroxisome Proliferator-Activated Receptor α Modulator (SPPARMα): Pooled Analysis of Phase 2 and 3 Studies in Dyslipidemic Patients with or without Statin Combination

Hypertriglyceridemia has emerged as an independent risk factor for cardiovascular events, despite low-density lipoprotein-cholesterol (LDL-C) well-controlled with statins. We pooled data from the first 12 weeks of six randomized double-blind placebo-controlled studies of pemafibrate in Japan and investigated its efficacy and safety with and without statins, particularly focusing on patients with renal dysfunction. Subjects were 1253 patients (677 in the "with-statin" group and 576 in the "without-statin" group). At Week 12 (last observation carried forward), triglyceride (TG) was significantly reduced at all pemafibrate doses (0.1, 0.2, and 0.4 mg/day), both with and without statin, compared to placebo (p < 0.001 vs. placebo for all groups). In the "with-statin" group, the estimated percent change from baseline was -2.0% for placebo and -45.1%, -48.5%, and -50.0%, respectively, for the pemafibrate groups. Findings for both groups showed significant decreases in TG-rich lipoproteins and atherogenic lipid parameters compared to placebo. The incidence of adverse events was similar between the pemafibrate and placebo groups and was also similar for patients with and without renal dysfunction in the "with-statin" group. Pemafibrate lowered TG and improved atherogenic dyslipidemia without a significant increase in adverse events in comparison to the placebo, even among "with-statin" patients who had renal dysfunction.

The selective peroxisome proliferator-activated receptor alpha modulator (SPPARMα) paradigm: conceptual framework and therapeutic potential : A consensus statement from the International Atherosclerosis Society (IAS) and the Residual Risk Reduction Initiative (R3i) Foundation

In the era of precision medicine, treatments that target specific modifiable characteristics of high-risk patients have the potential to lower further the residual risk of atherosclerotic cardiovascular events. Correction of atherogenic dyslipidemia, however, remains a major unmet clinical need. Elevated plasma triglycerides, with or without low levels of high-density lipoprotein cholesterol (HDL-C), offer a key modifiable component of this common dyslipidemia, especially in insulin resistant conditions such as type 2 diabetes mellitus. The development of selective peroxisome proliferator-activated receptor alpha modulators (SPPARMα) offers an approach to address this treatment gap. This Joint Consensus Panel appraised evidence for the first SPPARMα agonist and concluded that this agent represents a novel therapeutic class, distinct from fibrates, based on pharmacological activity, and, importantly, a safe hepatic and renal profile. The ongoing PROMINENT cardiovascular outcomes trial is testing in 10,000 patients with type 2 diabetes mellitus, elevated triglycerides, and low levels of HDL-C whether treatment with this SPPARMα agonist safely reduces residual cardiovascular risk.

Recent advances in synthetic pharmacotherapies for dyslipidaemias

Despite the demonstrated benefits of statins and injectable biologics, there is a need for new and safe oral agents for addressing classical lipid targets, low-density lipoprotein cholesterol (LDL-C), triglycerides and high-density lipoprotein cholesterol (HDL-C). LDL-C is unquestionably causal in the development of atherogenesis and atherosclerotic cardiovascular disease, but new options are required to address triglyceride-rich lipoproteins and lipoprotein(a). For hypercholesterolaemia, pitavastatin provides a very low dose and potent statin that does not adversely affect glucose metabolism; bempedoic acid acts at a biochemical step preceding hydroxymethylglutaryl-CoA reductase and is not associated with muscular side effects. For hypertriglyceridaemia, pemafibrate displays a unique and selective agonist activity on peroxisomal proliferator activated receptor-α that does not elevate homocysteine or creatinine. Although omega-3 fatty acids supplementation is not effective in secondary prevention, high dose eicosapentaenoic ethyl ester can lead to a remarkable fall in first and recurrent events in high risk patients with hypertriglyceridaemia/low HDL-C. Gemcabene, a dicarboxylic acid regulating apolipoprotein B-100, is effective in reducing both cholesterol and triglycerides. Among cholesteryl ester transfer protein antagonists that elevate HDL-C, only anacetrapib reduces cardiovascular events. Probucol stimulates reverse cholesteryl ester transport, lowers LDL-C stabilizing plaques and may lower incidence of cardiovascular events. These agents, which act through novel mechanisms, afford good and potentially safe treatment choices that may increase adherence and the attainment of therapeutic targets.

Clinical Applications of a Novel Selective PPARα Modulator, Pemafibrate, in Dyslipidemia and Metabolic Diseases

Fasting and postprandial hypertriglyceridemia is a risk factor for atherosclerotic cardiovascular diseases (ASCVD). Fibrates have been used to treat dyslipidemia, particularly hypertriglyceridemia, and low HDL-cholesterol (HDL-C). However, conventional fibrates have low selectivity for peroxisome proliferator-activated receptor (PPAR)α. Fibrates' clinical use causes side effects such as worsening liver function and elevating the creatinine level. Large-scale clinical trials of fibrates have shown negative results for prevention of ASCVD. To overcome these issues, the concept of the selective PPARα modulator (SPPARMα), with a superior balance of efficacy and safety, has been proposed. A SPPARMα, pemafibrate (K-877), was synthesized by Kowa Company, Ltd. for better efficacy and safety. Clinical trials conducted in Japan confirmed the superior effects of pemafibrate on triglyceride reduction and HDL-C elevation.

Conventional fibrates showed elevated liver function test values and worsened kidney function test values, while pemafibrate demonstrated improved liver function test values and was less likely to increase serum creatinine or decrease the estimated glomerular filtration rate. There were extremely few drug interactions even when it was used concomitantly with various statins. Furthermore, unlike many of the conventional fibrates that are renal excretory-type drugs, pemafibrate is excreted into the bile, so it can be safely used even in patients with impaired renal function and there is no increase in its blood concentration.

This novel SPPARMα, pemafibrate, has superior benefit-risk balance compared to conventional fibrates and can be used for patients for whom it was difficult to use existing fibrates, including those who are taking statins and those with renal dysfunction. A large-scale trial PROMINENT using pemafibrate for patients with type 2 diabetes is in progress. In the current review, the latest data on pemafibrate will be summarized.

Rationale and design of the Pemafibrate to Reduce Cardiovascular Outcomes by Reducing Triglycerides in Patients with Diabetes (PROMINENT) study

Observational, genetic, and experimental data indicate that triglyceride rich lipoproteins (TRLs) likely participate causally in atherothrombosis. Yet, robust clinical trial evidence that triglyceride (TG) lowering therapy reduces cardiovascular events remains elusive. The selective peroxisome proliferator-activated receptor alpha modulator (SPPARM-α), pemafibrate, will be used to target residual cardiovascular risk remaining after treatment to reduce low-density lipoprotein cholesterol (LDL-C) in individuals with the dyslipidemia of type 2 diabetes mellitus (T2). The PROMINENT study will randomly allocate approximately 10,000 participants with T2D, mild-to-moderate hypertriglyceridemia (TG: 200-499 mg/dl; 2.26-5.64 mmol/l) and low high-density lipoprotein cholesterol levels (HDL-C: ≤40 mg/dl; 1.03 mmol/l) to either pemafibrate (0.2 mg twice daily) or matching placebo with an average expected follow-up period of 3.75 years (total treatment phase 5 years; 24 countries). At study entry, participants must be receiving either moderate-to-high intensity statin therapy or meet specified LDL-C criteria. The study population will be one-third primary and two-thirds secondary prevention (established cardiovascular disease). The primary endpoint is a composite of nonfatal myocardial infarction, nonfatal ischemic stroke, hospitalization for unstable angina requiring urgent coronary revascularization, and cardiovascular death. This event-driven study will complete when 1092 adjudicated primary endpoints have accrued with at least 200 occurring in women. Statistical power is at least 90% to detect an 18% reduction in the primary endpoint. Pre-specified secondary and tertiary endpoints include all-cause mortality, hospitalization for heart failure, new or worsening peripheral artery disease, new or worsening diabetic retinopathy and nephropathy, and change in biomarkers including select lipid and non-lipid biomarkers, inflammatory and glycemic parameters.

Protein Residue Networks from Energetic and Geometric Data: Are They Identical?

Protein residue networks (PRN) from energetic and geometric data are probably not identical. PRNs constructed from ab initio pair interaction energies are analyzed for the first time and compared to PRN based on center of mass separation. We use modern, previously unused algorithms such as global and local efficiencies to quantitatively confirm that both types of PRNs do exhibit small-world character. The main novelty finding is that interaction energy-based PRNs preserve small-world character even when clustered. A node hierarchy independent of the cutoff energy used for the edge creation is characteristic for them. Efficiency centrality identifies hubs responsible for such behavior. The interaction energy-based PRNs seem to comply with the scale-free network model with respect to efficiency centrality distribution as opposed to distance based PRNs. Community detection is introduced into protein network research as an extension beyond cluster analysis to study tertiary and quaternary structures.

The Peroxisome Proliferator-Activated Receptor α (PPARα) Agonist Pemafibrate Protects against Diet-Induced Obesity in Mice

Peroxisome proliferator-activated receptor α (PPARα) is a therapeutic target for hyperlipidemia. Pemafibrate (K-877) is a new selective PPARα modulator activating PPARα transcriptional activity. To determine the effects of pemafibrate on diet-induced obesity, wild-type mice were fed a high-fat diet (HFD) containing pemafibrate for 12 weeks. Like fenofibrate, pemafibrate significantly suppressed HFD-induced body weight gain; decreased plasma glucose, insulin and triglyceride (TG) levels; and increased plasma fibroblast growth factor 21 (FGF21). However, compared to the dose of fenofibrate, a relatively low dose of pemafibrate showed these effects. Pemafibrate activated PPARα transcriptional activity in the liver, increasing both hepatic expression and plasma levels of FGF21. Additionally, pemafibrate increased the expression of genes involved in thermogenesis and fatty acid oxidation, including Ucp1, Cidea and Cpt1b in inguinal adipose tissue (iWAT) and the mitochondrial marker Elovl3 in brown adipose tissue (BAT). Therefore, pemafibrate activates thermogenesis in iWAT and BAT by increasing plasma levels of FGF21. Additionally, pemafibrate induced the expression of Atgl and Hsl in epididymal white adipose tissue, leading to the activation of lipolysis. Taken together, pemafibrate suppresses diet-induced obesity in mice and improves their obesity-related metabolic abnormalities. We propose that pemafibrate may be useful for the suppression and improvement of obesity-induced metabolic abnormalities.

Patent Highlights February-March 2018

A snapshot of noteworthy recent developments in the patent literature of relevance to pharmaceutical and medical research development.