Nifedipine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy, in ischaemic heart disease, hypertension and related cardiovascular disorders

Importance of the (Pro)renin Receptor in Activating the Renin-Angiotensin System During Normotensive and Preeclamptic Pregnancies

PURPOSE OF REVIEW

For a healthy pregnancy to occur, a controlled interplay between the maternal circulating renin-angiotensin-aldosterone system (RAAS), placental renin-angiotensin system (RAS) and intrarenal renin-angiotensin system (iRAS) is necessary. Functionally, both the RAAS and iRAS interact to maintain blood pressure and cardiac output, as well as fluid and electrolyte balance. The placental RAS is important for placental development while also influencing the maternal circulating RAAS and iRAS. This narrative review concentrates on the (pro)renin receptor ((P)RR) and its soluble form (s(P)RR) in the context of the hypertensive pregnancy pathology, preeclampsia.

RECENT FINDINGS

The (P)RR and the s(P)RR have become of particular interest as not only can they activate prorenin and renin, thus influencing levels of angiotensin II (Ang II), but s(P)RR has now been shown to directly interact with and stimulate the Angiotensin II type 1 receptor (AT1R). Levels of both placental (P)RR and maternal circulating s(P)RR are elevated in patients with preeclampsia. Furthermore, s(P)RR has been shown to increase blood pressure in non-pregnant and pregnant rats and mice. In preeclamptic pregnancies, which are characterised by maternal hypertension and impaired placental development and function, we propose that there is enhanced secretion of s(P)RR from the placenta into the maternal circulation. Due to its ability to both activate prorenin and act as an AT1R agonist, excess maternal circulating s(P)RR can act on both the maternal vasculature, and the kidney, leading to RAS over-activation. This results in dysregulation of the maternal circulating RAAS and overactivation of the iRAS, contributing to maternal hypertension, renal damage, and secondary changes to neurohumoral regulation of fluid and electrolyte balance, ultimately contributing to the pathophysiology of preeclampsia.

Structural biology of voltage-gated calcium channels

Voltage-gated calcium (Cav) channels mediate Ca2+ influx in response to membrane depolarization, playing critical roles in diverse physiological processes. Dysfunction or aberrant regulation of Cav channels can lead to life-threatening consequences. Cav-targeting drugs have been clinically used to treat cardiovascular and neuronal disorders for several decades. This review aims to provide an account of recent developments in the structural dissection of Cav channels. High-resolution structures have significantly advanced our understanding of the working and disease mechanisms of Cav channels, shed light on the molecular basis for their modulation, and elucidated the modes of actions (MOAs) of representative drugs and toxins. The progress in structural studies of Cav channels lays the foundation for future drug discovery efforts targeting Cav channelopathies.

Structural basis for human Cav1.2 inhibition by multiple drugs and the neurotoxin calciseptine

Cav1.2 channels play crucial roles in various neuronal and physiological processes. Here, we present cryo-EM structures of human Cav1.2, both in its apo form and in complex with several drugs, as well as the peptide neurotoxin calciseptine. Most structures, apo or bound to calciseptine, amlodipine, or a combination of amiodarone and sofosbuvir, exhibit a consistent inactivated conformation with a sealed gate, three up voltage-sensing domains (VSDs), and a down VSDII. Calciseptine sits on the shoulder of the pore domain, away from the permeation path. In contrast, when pinaverium bromide, an antispasmodic drug, is inserted into a cavity reminiscent of the IFM-binding site in Nav channels, a series of structural changes occur, including upward movement of VSDII coupled with dilation of the selectivity filter and its surrounding segments in repeat III. Meanwhile, S4-5III merges with S5III to become a single helix, resulting in a widened but still non-conductive intracellular gate.

Complex Spectroscopy Studies of Nifedipine Photodegradation

The aim of this work is to highlight the influence of UV light on the hydrolysis reaction of nifedipine (NIF) in the presence of alkaline solutions. In this context, the photodegradation of NIF in the absence of alkaline solutions caused (a) a change in the ratio between the absorbances of three bands in the UV-VIS spectra localized at 224-240 nm, 272-276 nm and 310-340 nm, assigned to the electronic transitions of -COOCH3 groups, -NO2 groups and a heterocycle with six atoms; (b) a red-shift of the photoluminescence (PL) band from 458 nm to 477 nm, simultaneous with an increase in its intensity; (c) a decrease in the ratio of the Raman line intensities, which peaked at 1224 cm-1 and 1649 cm-1, associated with the vibrational modes of -C-C-O in the ester group and C=C stretching; and (d) a decrease in the ratio between the absorbances of the IR bands, which peaked at 1493 cm-1 and 1223 cm-1, associated with the vibrational modes of the -NO2 group and C-N stretching. These changes were explained considering the NIF photodegradation reaction, which leads to the generation of the compound 4-(2-nitrosophenyl)-2.6-dimethyl-3.5-dimethoxy carbonyl pyridine. The interaction of NIF with NaOH in the absence of UV light was demonstrated to induce changes in the vibrational mode of the -C-C-O bond in the ester group. The photodegradation of NIF after its reaction with NaOH induces significant changes highlighted in its (a) UV-VIS spectra, by the shift of the absorption band at 238 nm; (b) PL spectra, by the supraunitary value of the ratio between the emission band intensities at 394-396 nm and 450 nm; (c) Raman spectra, by the change in the ratio between the intensities of the lines that peaked at 1224 cm-1 and 1649 cm-1 from 0.61 to 0.49; and (d) FTIR spectra, by the lowered absorbance of the IR band at 1493 cm-1 assigned to the vibrational mode of the -NO2 group as a result of the generation of the nitroso compound. These changes were explained considering the hydrolysis reaction products of NIF, as the nitroso compound is converted to a lactam-type compound. The photodegradation reaction rate constants of NIF and NIF after interaction with NaOH were also reported. The decrease in thermal stability of NIF samples after interaction with NaOH, as well as of NIF after exposure to UV light compared to NIF prior to exposure to UV light, was demonstrated by thermogravimetry, and the key fragments were confirmed by mass spectrometry.

Therapeutic improvements of nifedipine controlled-release tablets combined with sacubitril valsartan on patients with diabetic nephropathy complicated with hypertension

This study aimed to evaluate the efficacy of nifedipine controlled-release tablets combined with sacubitril valsartan in diabetic nephropathy (DN) patients with hypertension. One hundred and twelve DN patients with hypertension were enrolled. They were randomly divided into the control group (treated with nifedipine controlled-release tablets combined with valsartan) and the observation group (treated with nifedipine controlled-release tablets combined with sacubitril valsartan). Renal function, endothelial function and inflammatory response were examined. After three-months treatment, the levels of clinical indexes (glycosylated hemoglobin, fasting blood glucose, systolic and diastolic blood pressure), renal function indicators (urinary albumin excretion rate, blood urea nitrogen, serum creatinine and cystatin C), endothelial function indicators (microalbumin, angiotensin II, thrombomodulin and cartilage oligomeric matrix protein) and inflammatory response factors (interleukin-6 and tumor necrosis factor-α) in the observation group were significantly lower than those in the control group. Nifedipine controlled-release tablets combined with sacubitril valsartan could effectively alleviate the progression of DN combined with hypertension.

Effect of Gut Microbiota on the Pharmacokinetics of Nifedipine in Spontaneously Hypertensive Rats

The pharmacokinetic variability of nifedipine widely observed in the clinic cannot be fully explained by pharmacogenomics. As a new factor affecting drug metabolism, how the gut microbiota affects the pharmacokinetics of nifedipine needs to be explored. Spontaneously hypertensive rats (SHRs) have been commonly used in hypertension-related research and served as the experimental groups; Wistar rats were used as control groups. In this study, the bioavailability of nifedipine decreased by 18.62% (p < 0.05) in the SHRs compared with the Wistar rats. Changes in microbiota were associated with the difference in pharmacokinetics. The relative abundance of Bacteroides dorei was negatively correlated with AUC0-t (r = -0.881, p = 0.004) and Cmax (r = -0.714, p = 0.047). Analysis of serum bile acid (BA) profiles indicated that glycoursodeoxycholic acid (GUDCA) and glycochenodeoxycholic acid (GCDCA) were significantly increased in the SHRs. Compared with the Wistar rats, the expressions of CYP3A1 and PXR were upregulated and the enzyme activity of CYP3A1 increased in the SHRs. Spearman's rank correlation revealed that Bacteroides stercoris was negatively correlated with GUDCA (r = -0.7126, p = 0.0264) and GCDCA (r = -0.6878, p = 0.0339). Moreover, GUDCA was negatively correlated with Cmax (r = -0.556, p = 0.025). In primary rat hepatocytes, GUDCA could induce the expressions of PXR target genes CYP3A1 and Mdr1a. Furthermore, antibiotic treatments in SHRs verified the impact of microbiota on the pharmacokinetics of nifedipine. Generally, gut microbiota affects the pharmacokinetics of nifedipine through microbial biotransformation or by regulating the enzyme activity of CYP3A1.

Identification and Validation of a Novel Antibacterial Compound MZ-01 against Methicillin-Resistant Staphylococcus aureus

The discovery of new classes of antibiotics is slow, and it is being greatly outpaced by the development of bacterial resistance. This disparity places us in an increasingly vulnerable position because we are running out of safe and effective therapeutic options to treat antibiotic-resistant infections. This is exemplified by the emergence and persistence of hospital-acquired and community-associated methicillin-resistant S. aureus (MRSA), which has markedly narrowed our options for treating life-threatening staph infections. Thus, there is an urgent need to develop novel, potent, preventive, and therapeutic agents. In our current study, we performed a whole-cell screening assay of synthetic libraries for antibacterial activity and identified a novel molecule, MZ-01. MZ-01 exhibited potent bactericidal activity against Gram-positive bacterial pathogens, including MRSA, Streptococcus pyogenes, and Streptococcus pneumoniae, at low concentrations. MZ-01 killed and lysed both the late exponential phase of an S. aureus population and bacteria inside mammalian cells. Furthermore, MZ-01 exhibited low cytotoxicity. These results indicate that MZ-01 is a promising scaffold to guide the development of novel, potent antibacterial agents against multidrug-resistant Gram-positive bacterial pathogens such as MRSA.

Universal and Sensitive Drug Assessment Biosensing Platform Using Optimal Mechanical Beating Detection of Single Cardiomyocyte

The preclinical assessment of efficacy and safety is essential for cardiovascular drug development in order to guarantee effective prevention and treatment of cardiovascular disease and avoid human health endangerment and a huge waste of resources. Rhythmic mechanical beating as one of the crucial cardiomyocyte properties has been exploited to establish a drug assessment biosensing platform. However, the conventional label-free biosensing platforms are difficult to perform high-throughput and high-resolution mechanical beating detection for a single cardiomyocyte, while label-based strategies are limited by pharmacologically adverse effects and phototoxicity. Herein, we propose a biosensing platform involving the multichannel electrode array device and the universal mechanical beating detection system. The platform can determine the optimal characteristic working frequency of different devices and dynamically interrogate the viability of multisite single cardiomyocytes to establish the optimized cell-based model for sensitive drug assessment. The subtle changes of mechanical beating signals induced by cardiovascular drugs can be detected by the platform, thereby demonstrating its high performance in pharmacological assessment. The universal and sensitive drug assessment biosensing platform is believed to be widely applied in cardiology investigating and preclinical drug screening.

Design, Synthesis, and Biological Evaluation of Novel Dihydropyridine and Pyridine Analogs as Potent Human Tissue Nonspecific Alkaline Phosphatase Inhibitors with Anticancer Activity: ROS and DNA Damage-Induced Apoptosis

Small molecules with nitrogen-containing scaffolds have gained much attention due to their biological importance in the development of new anticancer agents. The present paper reports the synthesis of a library of new dihydropyridine and pyridine analogs with diverse pharmacophores. All compounds were tested against the human tissue nonspecific alkaline phosphatase (h-TNAP) enzyme. Most of the compounds showed excellent enzyme inhibition against h-TNAP, having IC₅₀ values ranging from 0.49 ± 0.025 to 8.8 ± 0.53 µM, which is multi-fold higher than that of the standard inhibitor (levamisole = 22.65 ± 1.60 µM) of the h-TNAP enzyme. Furthermore, an MTT assay was carried out to evaluate cytotoxicity against the HeLa and MCF-7 cancer cell lines. Among the analogs, the most potent dihydropyridine-based compound 4d was selected to investigate pro-apoptotic behavior. The further analysis demonstrated that compound 4d played a significant role in inducing apoptosis through multiple mechanisms, including overproduction of reactive oxygen species, mitochondrial dysfunction, DNA damaging, and arrest of the cell cycle at the G1 phase by inhibiting CDK4/6. The apoptosis-inducing effect of compound 4d was studied through staining agents, microscopic, and flow cytometry techniques. Detailed structure–activity relationship (SAR) and molecular docking studies were carried out to identify the core structural features responsible for inhibiting the enzymatic activity of the h-TNAP enzyme. Moreover, fluorescence emission studies corroborated the binding interaction of compound 4d with DNA through a fluorescence titration experiment.

Pharmacokinetics of the most commonly used antihypertensive drugs throughout pregnancy methyldopa, labetalol, and nifedipine: a systematic review

Purpose

Antihypertensive drugs are among the most prescribed drugs during pregnancy. Methyldopa, labetalol, and nifedipine have been perceived safe to use during pregnancy and are therefore recommended in international guidelines for treatment of hypertension. In this review, we provide a complete overview of what is known on the pharmacokinetics (PK) of the antihypertensive drugs methyldopa, labetalol, and nifedipine throughout pregnancy.

Methods

A systematic search was performed to retrieve studies on the PK of methyldopa, labetalol, and nifedipine used throughout pregnancy. The search was restricted to English and original studies. The systematic search was conducted on July 27, 2021, in Embase, Medline Ovid, Web of Science, Cochrane Library, and Google Scholar. Keywords were methyldopa, labetalol, nifedipine, pharmacokinetics, pregnancy, and placenta.

Results

A total of 1459 unique references were identified of which title and abstract were screened. Based on this screening, 67 full-text papers were assessed, to retain 30 PK studies of which 2 described methyldopa, 12 labetalol, and 16 nifedipine. No fetal accumulation is found for any of the antihypertensive drugs studied.

Conclusion

We conclude that despite decades of prescribing methyldopa, labetalol, and nifedipine throughout pregnancy, descriptions of their PK during pregnancy are hampered by a large heterogeneity in the low number of available studies. Aiming for evidence-based and personalized dosing of antihypertensive medication in the future, further studies on the relationship of both PK and pharmacodynamics (including the optimal blood pressure targeting) during pregnancy and pregnancy-related pathology are urgently needed to prevent undertreatment, overtreatment, and side effects.

Porous Polyethylene Terephthalate Nanotemplate Electrodes for Sensitive Intracellular Recording of Action Potentials

New strategies for intracellular electrophysiology break the spatiotemporal limitation of the action potential and lead a notable advance in the investigation of electrically excitable cells and their network. Although successful applications of intracellular recording have been achieved by 3D micro/nanodevices, complex micro/nanofabrication processes preclude the progress of extensive applications. We address this challenge by introducing porous polyethylene terephthalate (PET) membrane to develop a new type of nanotemplate electrode. This nanotemplate electrode is manufactured following a fabrication process on a porous PET membrane by atomic layer deposition. The 3D nanotemplate electrodes afford intracellular access to cardiomyocytes to report intracellular-like action potentials. These controllable nanotemplate electrodes exhibit sensitive and prolonged intracellular recordings of action potentials compared with free-growing 3D nanoelectrodes. This study indicates that the optimized structure of the nanoelectrode significantly promotes the performance of intracellular recording to assess electrophysiology in the fields of cardiology and neuroscience at an action potential level.

Effects of pharmacological agents for neurogenic oropharyngeal dysphagia: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the effects of pharmacological agents for neurogenic oropharyngeal dysphagia based on evidence from randomized controlled trials (RCTs).

METHODS

Electronic databases were systematically searched between January 1970 and March 2021. Two reviewers independently extracted and synthesized the data. The outcome measure was changed in (any) relevant clinical swallowing-related characteristics.

KEY RESULTS

Data from 2186 dysphagic patients were collected from 14 RCT studies across a range of pharmacotherapies. The pooled effect size of transient receptor potential (TRP) channel agonists was large compared to placebo interventions (SMD[95%CI] =1.27[0.74,1.80], p < 0.001; I2  = 79%). Data were limited for other pharmacological agents and the overall pooled effect size of these agents was non-significant (SMD [95% CI] =0.25 [-0.24, 0.73]; p = 0.31; I2  = 85%). When analyzed separately, large effect sizes were observed with Nifedipine (SMD[95%CI] =1.13[0.09,2.18]; p = 0.03) and Metoclopramide (SMD[95%CI] =1.68[1.08,2.27]; p < 0.001). By contrast, the effects of angiotensin-converting enzyme (ACE) inhibitors (SMD[95%CI] = -0.67[-2.32,0.99]; p = 0.43; I2  = 61%), Physostigmine (SMD[95%CI] = -0.05[-1.03,0.93]; p = 0.92) and Glyceryl Trinitrate (GTN) (SMD [95% CI] = -0.01 [-0.11, 0.08]; p = 0.78) were non-significant. Within stroke patients, subgroup analysis showed that TRP channel agonists had a moderate pooled effect size (SMD[95%CI] =0.74[0.10,1.39]; p = 0.02; I2  = 82%) whereas the effects of other agents were non-significant (SMD[95%CI] =0.40[-0.04,0.84]; p = 0.07; I2  = 87%).

CONCLUSIONS & INFERENCES

Our results showed that TRP channel agonists, Nifedipine and Metoclopromide may be beneficial for neurogenic dysphagic patients. Large scale, multicenter clinical trials are warranted to fully explore their therapeutic effects on swallowing.

Synthesis and Biological Activity of the Pyridine-Hexacyclic-Steroid Derivative on a Heart Failure Model

BACKGROUND

Several drugs with inotropic activity have been synthesized; however, there is very little information on biological activity exerted by steroid derivatives in the cardiovascular system.

OBJECTIVE

The aim of this research was to prepare a steroid-pyridine derivative to evaluate the effect it exerts on left ventricular pressure and characterize its molecular interaction.

METHODS

The first stage was carried out through the synthesis of a steroid-pyridine derivative using some chemical strategies. The second stage involved the evaluation of the biological activity of the steroid-pyridine derivative on left ventricular pressure using a model of heart failure in the absence or presence of the drugs, such as flutamide, tamoxifen, prazosin, metoprolol, indomethacin, and nifedipine.

RESULTS

The results showed that steroid-pyridine derivative increased left ventricular pressure in a dose-dependent manner (0.001-100 nM); however, this phenomenon was significantly inhibited only by nifedipine at a dose of 1 nM. These results indicate that positive inotropic activity produced by the steroid-pyridine derivative was via calcium channel activation. Furthermore, the biological activity exerted by the steroid-pyridine derivative on the left ventricle produces changes in cAMP concentration.

CONCLUSION

It is noteworthy that positive inotropic activity produced by this steroid-pyridine derivative involves a different molecular mechanism compared to other positive inotropic drugs. Therefore, this steroid could be a good candidate for the treatment of heart failure.

Quantitative Estimation of the Hydrogen-Atom-Donating Ability of 4-Substituted Hantzsch Ester Radical Cations

The purpose of this study is to investigate thermodynamic and kinetic properties on the hydrogen-atom-donating ability of 4-substituted Hantzsch ester radical cations (XRH•+), which are excellent NADH coenzyme models. Gibbs free energy changes and activation free energies of 17 XRH•+ releasing H• [denoted as ΔG HD o(XRH•+) and ΔG HD ≠(XRH•+)] were calculated using density functional theory (DFT) and compared with that of Hantzsch ester (HEH2) and NADH. ΔG HD o(XRH•+) range from 19.35 to 31.25 kcal/mol, significantly lower than that of common antioxidants (such as ascorbic acid, BHT, the NADH coenzyme, and so forth). ΔG HD ≠(XRH•+) range from 29.81 to 39.00 kcal/mol, indicating that XRH•+ spontaneously releasing H• are extremely slow unless catalysts or active intermediate radicals exist. According to the computed data, it can be inferred that the Gibbs free energies and activation free energies of the core 1,4-dihydropyridine radical cation structure (DPH•+) releasing H• [ΔG HD o(DPH•+) and ΔG HD ≠(DPH•+)] should be 19-32 kcal/mol and 29-39 kcal/mol in acetonitrile, respectively. The correlations between the thermodynamic driving force [ΔG HD o(XRH•+)] and the activation free energy [ΔG HD ≠(XRH•+)] are also explored. Gibbs free energy is the important and decisive parameter, and ΔG HD ≠(XRH•+) increases in company with the increase of ΔG HD o(XRH•+), but no simple linear correlations are found. Even though all XRH•+ are judged as excellent antioxidants from the thermodynamic view, the computed data indicate that whether XRH•+ is an excellent antioxidant in reaction is decided by the R substituents in 4-position. XRH•+ with nonaromatic substituents tend to release R• instead of H• to quench radicals. XRH•+ with aromatic substituents tend to release H• and be used as antioxidants, but not all aromatic substituted Hantzsch esters are excellent antioxidants.

Antiepileptic Drug Tiagabine Does Not Directly Target Key Cardiac Ion Channels Kv11.1, Nav1.5 and Cav1.2

Tiagabine is an antiepileptic drug used for the treatment of partial seizures in humans. Recently, this drug has been found useful in several non-epileptic conditions, including anxiety, chronic pain and sleep disorders. Since tachycardia-an impairment of cardiac rhythm due to cardiac ion channel dysfunction-is one of the most commonly reported non-neurological adverse effects of this drug, in the present paper we have undertaken pharmacological and numerical studies to assess a potential cardiovascular risk associated with the use of tiagabine. A chemical interaction of tiagabine with a model of human voltage-gated ion channels (VGICs) is described using the molecular docking method. The obtained in silico results imply that the adverse effects reported so far in the clinical cardiological of tiagabine could not be directly attributed to its interactions with VGICs. This is also confirmed by the results from the isolated organ studies (i.e., calcium entry blocking properties test) and in vivo (electrocardiogram study) assays of the present research. It was found that tachycardia and other tiagabine-induced cardiac complications are not due to a direct effect of this drug on ventricular depolarization and repolarization.

Structural Basis of the Modulation of the Voltage-Gated Calcium Ion Channel Cav 1.1 by Dihydropyridine Compounds*

1,4-Dihydropyridines (DHP), the most commonly used antihypertensives, function by inhibiting the L-type voltage-gated Ca2+ (Cav ) channels. DHP compounds exhibit chirality-specific antagonistic or agonistic effects. The structure of rabbit Cav 1.1 bound to an achiral drug nifedipine reveals the general binding mode for DHP drugs, but the molecular basis for chiral specificity remained elusive. Herein, we report five cryo-EM structures of nanodisc-embedded Cav 1.1 in the presence of the bestselling drug amlodipine, a DHP antagonist (R)-(+)-Bay K8644, and a titration of its agonistic enantiomer (S)-(-)-Bay K8644 at resolutions of 2.9-3.4 Å. The amlodipine-bound structure reveals the molecular basis for the high efficacy of the drug. All structures with the addition of the Bay K8644 enantiomers exhibit similar inactivated conformations, suggesting that (S)-(-)-Bay K8644, when acting as an agonist, is insufficient to lock the activated state of the channel for a prolonged duration.

Hypotensive and Antihypertensive Properties and Safety for Use of Annona muricata and Persea americana and Their Combination Products

Introduction

In the management of hypertension (a cardiovascular disease and the leading metabolic risk factor in noncommunicable diseases) with herbal medicines, efficacy and safety are of uttermost concern. This study sought to establish hypotensive, antihypertensive, drug interaction, and safety for use of the aqueous leaf extracts of Annona muricata (AME), Persea americana (PAE), or their combination products (CAPE). Methodology. Systolic and diastolic blood pressure (SBP and DBP), mean arterial blood pressure (MAP), and heart rate (HR) were measured in normotensive Sprague-Dawley rats treated with 50-150 mg/kg of AME, PAE, or CAPE to establish a hypotensive effect. "Combination index" was calculated to establish interaction between AME and PAE. The antihypertensive effect of CAPE was established by measuring SBP, DBP, MAP, and HR in ethanol-sucrose- and epinephrine-induced hypertension. Full blood count, liver and kidney function tests, and urinalysis were determined in ethanol/sucrose-induced hypertension to establish safety for use.

Results

AME, PAE, and CAPE significantly (p ≤ 0.001) decreased BP in both normotensive and hypertensive animals. Effects of CAPE 1, CAPE 2, and CAPE 3 were synergistic (combination indices of 0.65 ± 0.07, 0.76 ± 0.09, and 0.87 ± 0.07, respectively). There was a significant decrease (p ≤ 0.01 - 0.001) in SBP and MAP with 100 mg/kg CAPE 1 and 75 mg/kg CAPE 2 treatment in hypertension as well as with nifedipine (p ≤ 0.001) treatment. Epinephrine-induced hypertension in anesthetized cats was significantly and dose-dependently inhibited (p < 0.05 - 0.001) by 25-100 mg/ml CAPE 1 and 37.5-75 mg/ml CAPE 2. CAPE administration had no deleterious effect (p > 0.05) on full blood count, liver and kidney function, and urine composition in hypertensive rats.

Conclusion

The aqueous leaf extracts of Annona muricata, Persea americana, and their combination products possess antihypertensive properties, with combination products showing synergism and safety with use.

Adaptable pulsatile flow generated from stem cell-derived cardiomyocytes using quantitative imaging-based signal transduction

Endothelial cells (EC) in vivo are continuously exposed to a mechanical microenvironment from blood flow, and fluidic shear stress plays an important role in EC behavior. New approaches to generate physiologically and pathologically relevant pulsatile flows are needed to understand EC behavior under different shear stress regimes. Here, we demonstrate an adaptable pump (Adapt-Pump) platform for generating pulsatile flows from human pluripotent stem cell-derived cardiac spheroids (CS) via quantitative imaging-based signal transduction. Pulsatile flows generated from the Adapt-Pump system can recapitulate unique CS contraction characteristics, accurately model responses to clinically relevant drugs, and simulate CS contraction changes in response to fluidic mechanical stimulation. We discovered that ECs differentiated under a long QT syndrome derived pathological pulsatile flow exhibit abnormal EC monolayer organization. This Adapt-Pump platform provides a powerful tool for modeling the cardiovascular system and improving our understanding of EC behavior under different mechanical microenvironments.

Molecular Basis for Ligand Modulation of a Mammalian Voltage-Gated Ca2+ Channel

The L-type voltage-gated Ca²⁺ (Ca_v) channels are modulated by various compounds exemplified by 1,4-dihydropyridines (DHP), benzothiazepines (BTZ), and phenylalkylamines (PAA), many of which have been used for characterizing channel properties and for treatment of hypertension and other disorders. Here, we report the cryoelectron microscopy (cryo-EM) structures of Ca_v1.1 in complex with archetypal antagonistic drugs, nifedipine, diltiazem, and verapamil, at resolutions of 2.9 Å, 3.0 Å, and 2.7 Å, respectively, and with a DHP agonist Bay K 8644 at 2.8 Å. Diltiazem and verapamil traverse the central cavity of the pore domain, directly blocking ion permeation. Although nifedipine and Bay K 8644 occupy the same fenestration site at the interface of repeats III and IV, the coordination details support previous functional observations that Bay K 8644 is less favored in the inactivated state. These structures elucidate the modes of action of different Ca_v ligands and establish a framework for structure-guided drug discovery.

Follicular dendritic cell-secreted protein gene expression is upregulated and spread in nifedipine-induced gingival overgrowth

Follicular dendritic cell-secreted protein (FDC-SP) is secreted protein expressed in follicular dendritic cells, periodontal ligament and junctional epithelium (JE). Its expression could be controlled during inflammatory process of gingiva; however, responsible mechanism for gingival overgrowth and involvement of FDC-SP in clinical condition is still unclear. We hypothesized that JE-specific genes are associated with the initiation of drug-induced gingival enlargement (DIGE) called gingival overgrowth, and investigated the changes of JE-specific gene's expression and their localization in overgrown gingiva from the patients. Immunohistochemical analysis revealed that the FDC-SP localization was spread in overgrown gingival tissues. FDC-SP mRNA levels in GE1 and Ca9-22 cells were increased by time-dependent nifedipine treatments, similar to other JE-specific genes, such as Amelotin (Amtn) and Lamininβ3 subunit (Lamβ3), whereas type 4 collagen (Col4) mRNA levels were decreased. Immunocytochemical analysis showed that FDC-SP, AMTN, and Lamβ3 protein levels were increased in GE1 and Ca9-22 cells. Transient transfection analyses were performed using luciferase constructs including various lengths of human FDC-SP gene promoter, nifedipine increased luciferase activities of -345 and -948FDC-SP constructs. These results raise the possibility that the nifedipine-induced FDC-SP may be related to the mechanism responsible for gingival overgrowth does not occur at edentulous jaw ridges.

A Na+ /Ca2+ exchanger of the olive pathogen Pseudomonas savastanoi pv. savastanoi is critical for its virulence

In a number of compatible plant-bacterium interactions, a rise in apoplastic Ca2+ levels is observed, suggesting that Ca2+ represents an important environmental clue, as reported for bacteria infecting mammalians. We demonstrate that Ca2+ entry in Pseudomonas savastanoi pv. savastanoi (Psav) strain DAPP-PG 722 is mediated by a Na+ /Ca2+ exchanger critical for virulence. Using the fluorescent Ca2+ probe Fura 2-AM, we demonstrate that Ca2+ enters Psav cells foremost when they experience low levels of energy, a situation mimicking the apoplastic fluid. In fact, Ca2+ entry was suppressed in the presence of high concentrations of glucose, fructose, sucrose or adenosine triphosphate (ATP). Since Ca2+ entry was inhibited by nifedipine and LiCl, we conclude that the channel for Ca2+ entry is a Na+ /Ca2+ exchanger. In silico analysis of the Psav DAPP-PG 722 genome revealed the presence of a single gene coding for a Na+ /Ca2+ exchanger (cneA), which is a widely conserved and ancestral gene within the P. syringae complex based on gene phylogeny. Mutation of cneA compromised not only Ca2+ entry, but also compromised the Hypersensitive response (HR) in tobacco leaves and blocked the ability to induce knots in olive stems. The expression of both pathogenicity (hrpL, hrpA and iaaM) and virulence (ptz) genes was reduced in this Psav-cneA mutant. Complementation of the Psav-cneA mutation restored both Ca2+ entry and pathogenicity in olive plants, but failed to restore the HR in tobacco leaves. In conclusion, Ca2+ entry acts as a 'host signal' that allows and promotes Psav pathogenicity on olive plants.

Taming photo-induced oxidation degradation of dihydropyridine drugs through cocrystallization

Cocrystallization of nifedipine (NFD) and isonicotinamide (INA) resulted in two monotropic cocrystal polymorphs. The thermodynamically more stable polymorph presents superior photostability compared to the other. Cocrystallization can be an efficient approach to address the stability deficit of dihydropyridine drugs.

Salinomycin induced ROS results in abortive autophagy and leads to regulated necrosis in glioblastoma

Glioblastoma is the most frequent malignant brain tumor. Even with aggressive treatment, prognosis for patients is poor. One characteristic of glioblastoma cells is its intrinsic resistance to apoptosis. Therefore, drugs that induce alternative cell deaths could be interesting to evaluate as alternative therapeutic candidates for glioblastoma. Salinomycin (SLM) was identified through a chemical screening as a promising anticancer drug, but its mechanism of cell death remains unclear. In the present work we set out to elucidate how SLM causes cell death in glioblastoma cell lines (both established cell lines and brain tumor stem cell lines), aiming to find a potential antitumor candidate. In addition, we sought to determine the mechanism of action of SLM so that this mechanism can be can be exploited in the fight against cancer. Our data showed that SLM induces a potent endoplasmic reticulum (ER) stress followed by the trigger of the unfolded protein response (UPR) and an aberrant autophagic flux that culminated in necrosis due to mitochondria and lysosomal alterations. Of importance, the aberrant autophagic flux was orchestrated by the production of Reactive Oxygen Species (ROS). Alleviation of ROS production restored the autophagic flux. Altogether our data suggest that in our system the oxidative stress blocks the autophagic flux through lipid oxidation. Importantly, oxidative stress could be instructing the type of cell death in SLM-treated cells, suggesting that cell death modality is a dynamic concept which depends on the cellular stresses and the cellular mechanism activated.

Quality by Design Empowered Development and Optimisation of Time-Controlled Pulsatile Release Platform Formulation Employing Compression Coating Technology

The research was envisaged for development of time-controlled pulsatile release (PR) platform formulation to facilitate management of early morning chronological attacks. The development was started using prednisone as a model drug wherein core tablets were prepared using direct compression method and subsequently compression-coated with ethylcellulose (EC)-hydroxypropyl methylcellulose (HPMC) excipient blend. Initially, quality target product profile was established and risk assessment was performed using failure mode and effect analysis. In an endeavour to accomplish the objective, central composite design was employed as a design of experiment (DoE) tool. Optimised compression-coated tablet (CCT) exhibited 4-6 h lag time followed by burst release profile under variegated dissolution conditions viz. multi-media, change in apparatus/agitation and biorelevant media. Afterwards, five different drugs, i.e. methylprednisolone, diclofenac sodium, diltiazem hydrochloride, nifedipine and lornoxicam, were one-by-one incorporated into the optimised prednisone formula with replacement of former drug. Change in drug precipitated the issues like poor solubility and flow property which were respectively resolved through formulation of solid dispersion and preparation of active pharmaceutical ingredient (API) granules. Albeit, all drug CCTs exhibited desired release profile similar to prednisone CCTs. In nutshell, tour de force of research epitomised the objective of incorporating diverse drug molecules and penultimately obtaining robust release profile at varying dissolution conditions.

4-Nitro styrylquinoline is an antimalarial inhibiting multiple stages of Plasmodium falciparum asexual life cycle

Drugs against malaria are losing their effectiveness because of emerging drug resistance. This underscores the need for novel therapeutic options for malaria with mechanism of actions distinct from current antimalarials. To identify novel pharmacophores against malaria we have screened compounds containing structural features of natural products that are pharmacologically relevant. This screening has identified a 4-nitro styrylquinoline (SQ) compound with submicromolar antiplasmodial activity and excellent selectivity. SQ exhibits a cellular action distinct from current antimalarials, acting early on malaria parasite's intraerythrocytic life cycle including merozoite invasion. The compound is a fast-acting parasitocidal agent and also exhibits curative property in the rodent malaria model when administered orally. In this report, we describe the synthesis, preliminary structure-function analysis, and the parasite developmental stage specific action of the SQ scaffold.

Effect of type 2 diabetes mellitus on the pharmacokinetics and transplacental transfer of nifedipine in hypertensive pregnant women

AIMS

Diabetes mellitus can inhibit cytochrome P450 3A4, an enzyme responsible for the metabolism of nifedipine, used for the treatment of hypertension in pregnant women. We aimed to assess the effect of type 2 diabetes mellitus (T2DM) on the pharmacokinetics, placental transfer and distribution of nifedipine in amniotic fluid in hypertensive pregnant women.

METHODS

The study was conducted in 12 hypertensive pregnant women [control group (CG)] and 10 hypertensive pregnant women with T2DM taking slow-release nifedipine (20 mg, 12/12 h). On the 34th week of gestation, serial blood samples were collected (0-12 h) after administration of the medication. At delivery, samples of maternal and fetal blood and amniotic fluid were collected for determination of nifedipine distribution in these compartments.

RESULTS

The median pharmacokinetic parameters of CG were: peak plasma concentration (C_max ) 26.41 ng ml^-1 , time to reach C_max (t_max ) 1.79 h, area under the plasma concentration vs. time curve from 0-12 h (AUC_0-12 ) 235.99 ng.h ml^-1 , half-life (t½) 4.34 h, volume of distribution divided by bioavailability (Vd/F) 560.96 l, and Cl_T /F 84.77 l h^-1 . The parameters for T2DM group were: C_max 23.52 ng ml^-1 , t_max 1.48 h, AUC_0-12 202.23 ng.h ml^-1 , t½ 5.00 h, Vd/F 609.40 l, and apparent total clearance (Cl_T /F) 98.94 l h^-1 . The ratios of plasma concentrations of nifedipine in the umbilical vein, intervillous space and amniotic fluid to those in the maternal vein for CG and T2DM were 0.53 and 0.44, 0.78 and 0.87, respectively, with an amniotic fluid/maternal plasma ratio of 0.05 for both groups. The ratios of plasma concentrations in the umbilical artery to those in the umbilical vein were 0.82 for CG and 0.88 for T2DM.

CONCLUSIONS

There was no influence of T2DM on the pharmacokinetics or placental transfer of nifedipine in hypertensive women with controlled diabetes.

Medium throughput biochemical compound screening identifies novel agents for pharmacotherapy of neurofibromatosis type 1

The variable manifestation of phenotypes that occur in patients with neurofibromatosis type 1 (NF1) includes benign and malignant neurocutaneous tumors for which no adequate treatment exists. Cell-based screening of known bioactive compounds library identified the protein phosphatase 2A (PP2A) inhibitor Cantharidin and the L-type calcium channel blocker Nifedipine as potential candidates for NF1 pharmacotherapy. Validation of screening results using human NF1-associated malignant peripheral nerve sheath tumor (MPNST) cells showed that Cantharidin effectively impeded MPNST cell growth, while Nifedipine treatment significantly decreased local tumor growth in an MPNST xenograft animal model. These data suggest that inhibitors of PP2A, as well as calcium channel blockers, might be used in broader MPNST preclinical studies as single agents or in combinatorial therapeutic strategies.

A review of oral labetalol and nifedipine in mild to moderate hypertension in pregnancy

Hypertension is the most commonly encountered medical condition in pregnancy, contributing significantly to maternal and perinatal morbidity and mortality. Mild to moderate hypertension in pregnancy is defined as systolic blood pressure of 140-159 mmHg or diastolic blood pressure of 90-109 mmHg (7-9% of pregnancies). When treating hypertension in pregnancy, not only do physiologic changes of pregnancy have an effect on the pharmacokinetics and pharmacodynamics of the drugs used, but the pathophysiology of hypertensive disorders of pregnancy also have an effect. To date, evidence is lacking on the pharmacokinetics and pharmacodynamics of commonly used antihypertensive drugs, which often times leads to suboptimal treatment of hypertensive pregnant women. When considering which agents to use for treatment of mild to moderate hypertension, specifically in gestational and chronic hypertension, oral labetalol and nifedipine are valid options. An overview of the profile for use, safety, and current pharmacokinetic data for each agent is presented here.

Maternal and fetal haemodynamic effects of nifedipine in normotensive pregnant women

While nifedipine is commonly used for tocolysis, the controversy on its safety remains. So far, the haemodynamic effects on maternal and fetal circulations have not been well documented. Fifteen normotensive women who received 20 mg nifedipine were included in this prospective observational study. The maternal and fetal haemodynamic effects were analysed using maternal echocardiography and fetal Doppler ultrasonography. Nifedipine induced a significant afterload reduction in all women. It triggered a compensatory increase in cardiac output, which maintained blood pressure. These maternal changes had no influence on the uteroplacental and fetal circulations.

N-Heterocyclic carbene-catalyzed [3+3] cyclocondensation of bromoenals with aldimines: highly enantioselective synthesis of dihydropyridinones

The N-heterocyclic carbene-catalyzed [3+3] cyclocondensation of bromoenals and aldimines was developed, giving the corresponding dihydropyridinones in good yields with excellent enantioselectivities.

Effects of pioglitazone on the pharmacokinetics of nifedipine and its main metabolite, dehydronifedipine, in rats

The purpose of this study was to investigate the possible effects of pioglitazone on the pharmacokinetics of nifedipine and its main metabolite, dehydronifedipine, in rats. The effects of pioglitazone on P-glycoprotein (P-gp) and cytochrome P450 (CYP)3A4 activities were also evaluated. Nifedipine was mainly metabolized by CYP3A4. The pharmacokinetic parameters of nifedipine and dehydronifedipine were determined after oral and intravenous administrations of nifedipine to rats in the presence and absence of pioglitazone (0.3 and 1.0 mg/kg). Pioglitazone inhibited the CYP3A4 enzyme activity in a concentration-dependent manner. Inhibitory concentration (IC50) was 12.1 μM. In addition, pioglitazone significantly increased the cellular accumulation of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp. The areas under the plasma concentration-time curve (AUC0-∞) and the peak plasma concentration (C max) of nifedipine were significantly increased by 52.1 and 59.1 %, respectively, in the presence of pioglitazone (1.0 mg/kg) compared with control group. The total body clearance (CL/F) of nifedipine was significantly (1.0 mg/kg) decreased by pioglitazone (35.8 %). Consequently, the absolute bioavailability (AB) of nifedipine in the presence of pioglitazone (1.0 mg/kg) was significantly higher (25.3 %) than that of the control. The metabolite-parent AUC ratio (MR) in the presence of pioglitazone (1.0 mg/kg) significantly decreased (23.9 %) compared to that of the control group. The increased bioavailability of nifedipine in the presence of pioglitazone may be due to an inhibition of the P-gp-mediated efflux transporter in the small intestine and to the inhibition of the metabolism by inhibition of CYP3A4 in the small intestine and/or the liver, and/or to a reduction of CL/F of nifedipine by pioglitazone.

Effects of licochalcone A on the bioavailability and pharmacokinetics of nifedipine in rats: possible role of intestinal CYP3A4 and P-gp inhibition by licochalcone A

The purpose of this study was to investigate the possible effects of licochalcone A (a herbal medicine) on the pharmacokinetics of nifedipine and its main metabolite, dehydronifedipine, in rats. The pharmacokinetic parameters of nifedipine and/or dehydronifedipine were determined after oral and intravenous administration of nifedipine to rats in the absence (control) and presence of licochalcone A (0.4, 2.0 and 10 mg/kg). The effect of licochalcone A on P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4 activity was also evaluated. Nifedipine was mainly metabolized by CYP3A4. Licochalcone A inhibited CYP3A4 enzyme activity in a concentration-dependent manner with a 50% inhibition concentration (IC50 ) of 5.9 μm. In addition, licochalcone A significantly enhanced the cellular accumulation of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp. The area under the plasma concentration-time curve from time 0 to infinity (AUC) and the peak plasma concentration (Cmax ) of oral nifedipine were significantly greater and higher, respectively, with licochalcone A. The metabolite (dehydronifedipine)-parent AUC ratio (MR) in the presence of licochalcone A was significantly smaller compared with the control group. The above data could be due to an inhibition of intestinal CYP3A4 and P-gp by licochalcone A. The AUCs of intravenous nifedipine were comparable without and with licochalcone A, suggesting that inhibition of hepatic CYP3A4 and P-gp was almost negligible.

Nitro drugs for the treatment of trypanosomatid diseases: past, present, and future prospects

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Two nitro drugs are currently used in the treatment of trypanosomatid diseases.

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Several new nitroaromatics are being developed against the trypanosomatid diseases.

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Many nitro drugs and drug candidates act as prodrugs which require bioactivation.

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Nitroaromatics can have disparate mechanisms of action in trypanosomatid parasites.

There is an urgent need for new, safer, and effective treatments for the diseases caused by the protozoan parasites Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. In the search for more effective drugs to treat these ‘neglected diseases’ researchers have chosen to reassess the therapeutic value of nitroaromatic compounds. Previously avoided in drug discovery programs owing to potential toxicity issues, a nitro drug is now being used successfully as part of a combination therapy for human African trypanosomiasis. We describe here the rehabilitation of nitro drugs for the treatment of trypanosomatid diseases and discuss the future prospects for this compound class.

Nifedipine gastrointestinal therapeutic system (GITS) in the treatment of coronary heart disease and hypertension

Since the 1960s, calcium antagonists have been available for the treatment of angina pectoris and hypertension. The first of this class, nifedipine, was introduced and readily accepted as the third treatment option for angina, alongside beta-blockers and nitrates. However, the short-acting formulations of nifedipine had pharmacokinetic properties that were far from ideal and in 1995, several studies involving various dosing regimens reported possible dangerous effects in secondary prevention. Since then, large-scale, randomized controlled trials with new controlled-released formulations of nifedipine have demonstrated the effectiveness and safety of this drug. As a consequence of these results, guidelines for both hypertension and angina pectoris have been recently reconsidered, and have put the modern formulations of calcium channel blockers in a pole position. Within this group of therapeutics, nifedipine gastrointestinal therapeutic system has a unique position and it cannot be replaced by other controlled-release formulations of nifedipine, the pharmaceutical properties of which have yet to be tested in large-scale outcome trials.

Nifedipine prevents etoposide-induced caspase-3 activation, prenyl transferase degradation and loss in cell viability in pancreatic β-cells

Emerging evidence implicates novel roles for post-translational prenylation (i.e., farnesylation and geranylgeranylation) of various signaling proteins in a variety of cellular functions including hormone secretion, survival and apoptosis. In the context of cellular apoptosis, it has been shown previously that caspase-3 activation, a hallmark of mitochondrial dysregulation, promotes hydrolysis of several key cellular proteins. We report herein that exposure of insulin-secreting INS 832/13 cells or normal rat islets to etoposide leads to significant activation of caspase-3 and subsequent degradation of the common α-subunit of farnesyl/geranylgeranyl transferases (FTase/GGTase). Furthermore, the above stated signaling steps were prevented by Z-DEVD-FMK, a known inhibitor of caspase-3. In addition, treatment of cell lysates with recombinant caspase-3 also caused FTase/GGTase α-subunit degradation. Moreover, nifedipine, a calcium channel blocker, markedly attenuated etoposide-induced caspase-3 activation, FTase/GGTase α-subunit degradation in INS 832/13 cells and normal rat islets. Further, nifedipine significantly restored etoposide-induced loss in metabolic cell viability in INS 832/13 cells. Based on these findings, we conclude that etoposide induces loss in cell viability by inducing mitochondrial dysfunction, caspase-3 activation and degradation of FTase/GGTase α-subunit. Potential significance of these findings in the context of protein prenylation and β-cell survival are discussed.

Nifedipine induces periostin expression in gingival fibroblasts through TGF-beta

Gingival enlargement is a fibrotic condition that can arise from systemic administration of the dihydropyridine calcium channel blocker nifedipine. Periostin, a transforming growth factor-beta (TGF-β)-inducible matricellular protein, has been associated with fibrosis in numerous tissues, but its expression has never been examined in nifedipine-influenced gingival enlargement (NIGE). The objective of this study was to assess if periostin up-regulation is associated with NIGE and whether nifedipine induces periostin expression in gingival fibroblasts. In NIGE tissue (n = 6), periostin is overexpressed in the gingival connective tissue compared with healthy control tissue (n = 6). The transcription factor p-SMAD2/3, which is associated with canonical TGF-β signaling, localizes to the nuclei in both HGFs and oral epithelial cells in NIGE tissues, but not in control healthy tissue. In vitro culture of HGFs with 30 and 100 ng/mL of nifedipine significantly increased periostin mRNA and protein levels, which correlated with increased levels of active TGF-β and increased phosphorylation and nuclear localization of SMAD3. Blocking of canonical TGF-β signaling through inhibition of the TGF-β receptor I with SB431542 significantly reduced nifedipine-induced SMAD3 phosphorylation and periostin expression. Our results demonstrate that nifedipine up-regulates periostin in HGFs in a TGF-β-dependent manner.