Anti-atrial Fibrillatory and Cardiorenal Protective Effects of the Combination of Valsartan and Cilnidipine in Dahl Salt-Sensitive Rats.

The current study aimed to investigate the anti-atrial fibrillatory (AF) effects of a combination of valsartan and a calcium channel blocker (cilnidipine or amlodipine) in Dahl salt-sensitive (Dahl S) rats. Seven-week-old male Dahl S rats were fed an 8% salt diet. Six weeks later, valsartan (60 mg/kg, Val group), cilnidipine + valsartan (10 + 60 mg/kg, CV group), amlodipine + valsartan (3 + 60 mg/kg, AV group), or vehicle was orally administered daily for 5 weeks. Echocardiography and atrial electrophysiological evaluations were performed on the last day of treatment. Blood pressure in each drug treatment group was lower than in the Vehicle group. The duration of AF induced by atrial burst stimulation was shorter in the Val group (3.2 ± 1.6 s) than in the Vehicle group (11.2 ± 6.0 s), which was further shortened in the CV and AV groups (1.1 ± 0.3 and 1.3 ± 0.3 s, respectively). Left ventricular ejection fraction and left ventricular fractional shortening were greater in the CV and AV groups than those in the Vehicle group. Urinary albumin excretion in the CV group was the lowest among the drug-treated groups. The results collectively suggest that the combination of a calcium channel blocker with valsartan could be useful in terms of its anti-AF action as well as for improving cardiac and renal functions.

Design, Synthesis, and Biological Evaluation of 1,4-Dihydropyridine-Indole as a Potential Antidiabetic Agent via GLUT4 Translocation Stimulation.

In the quest for the discovery of antidiabetic compounds, a series of 27 1,4-dihydropyridine-indole derivatives were synthesized using a diversity approach. These compounds were systematically evaluated for their antidiabetic activity, starting with an in vitro assessment for GLUT4 translocation stimulation in L6-GLUT4myc myotubes, followed by in vivo antihyperglycemic activity evaluation in a streptozotocin (STZ)-induced diabetic rat model. Among the synthesized compounds, 12, 14, 15, 16, 19, 27, and 35 demonstrated significant potential to stimulate GLUT4 translocation in skeletal muscle cells. Compound 19 exhibited the highest potency and was selected for in vivo evaluation. A notable reduction of 21.6% (p < 0.01) in blood glucose levels was observed after 5 h of treatment with compound 19 in STZ-induced diabetic rats. Furthermore, pharmacokinetic studies affirmed that compound 19 was favorable to oral exposure with suitable pharmacological parameters. Overall, compound 19 emerged as a promising lead compound for further structural modification and optimization.

Cilnidipine, a Dual L/N-type Ca2+ Channel Blocker in Hypertension Management: A Review.

Calcium channel blockers (CCBs) are widely used antihypertensive agents due to their effectiveness in reducing blood pressure (BP), along with their good tolerability and evidence of reducing hypertension (HTN)-related cardiovascular and renal diseases. Cilnidipine, a unique dihydropyridine calcium antagonist, exhibits potent inhibitory action on both N-type and L-type voltage-dependent calcium channels. With excellent oral absorption and a prolonged duration of action, it demonstrates a significant antihypertensive effect. It effectively reduces BP both systolic and diastolic while providing renal, neurological, and cardiovascular protection. Unlike L-type CCBs, cilnidipine does not increase pulse rates (PRs) and is associated with reduced occurrence of pedal edema. Cilnidipine is an effective treatment choice for individuals with mild to moderate essential HTN, whether it is administered alone or in conjunction with other treatment modalities.

18F-Labeled dihydropyridines via Hantzsch reaction for positron emission tomography of P-glycoprotein dysfunction.

Despite the availability of various 11C-labeled positron emission tomography (PET) tracers for assessing P-glycoprotein (P-gp) function, there are still limitations related to complex metabolism, high lipophilicity, and low baseline uptake. This study aimed to address these issues by exploring a series of customized dihydropyridines (DHPs) with enhanced stability and reduced lipophilicity as alternative PET tracers for P-gp dysfunction. Compared with verapamil and the rest DHPs, dimethyl 4-(4-fluorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (1) exhibited superior cellular uptake differences between the human gastric cancer cell line SGC7901 and its drug-resistant counterpart. [18F]1 is successfully synthesized using a novel "hot-Hantzsch" approach in 22.1 ± 0.1 % radiochemical yields. MicroPET/CT imaging demonstrated that the uptake of [18F]1 in the brains of P-gp blocked mice increased by > 3 times compared to the control group. Additionally, [18F]1 displayed favorable lipophilicity (log D = 2.3) and excellent clearance characteristics, making it a promising tracer candidate with low background noise and high contrast.

Optimization of diastereomeric dihydropyridines as antimalarials.

The increase in research funding for the development of antimalarials since 2000 has led to a surge of new chemotypes with potent antimalarial activity. High-throughput screens have delivered several thousand new active compounds in several hundred series, including the 4,7-diphenyl-1,4,5,6,7,8-hexahydroquinolines, hereafter termed dihydropyridines (DHPs). We optimized the DHPs for antimalarial activity. Structure-activity relationship studies focusing on the 2-, 3-, 4-, 6-, and 7-positions of the DHP core led to the identification of compounds potent (EC50 < 10 nM) against all strains of P. falciparum tested, including the drug-resistant parasite strains K1, W2, and TM90-C2B. Evaluation of efficacy of several compounds in vivo identified two compounds that reduced parasitemia by >75 % in mice 6 days post-exposure following a single 50 mg/kg oral dose. Resistance acquisition experiments with a selected dihydropyridine led to the identification of a single mutation conveying resistance in the gene encoding for Plasmodium falciparum multi-drug resistance protein 1 (PfMDR1). The same dihydropyridine possessed transmission blocking activity. The DHPs have the potential for the development of novel antimalarial drug candidates.

Inhibition of Drp1-Filamin Protein Complex Prevents Hepatic Lipid Droplet Accumulation by Increasing Mitochondria-Lipid Droplet Contact.

Lipid droplet (LD) accumulation in hepatocytes is one of the major symptoms associated with fatty liver disease. Mitochondria play a key role in catabolizing fatty acids for energy production through ß-oxidation. The interplay between mitochondria and LD assumes a crucial role in lipid metabolism, while it is obscure how mitochondrial morphology affects systemic lipid metabolism in the liver. We previously reported that cilnidipine, an already existing anti-hypertensive drug, can prevent pathological mitochondrial fission by inhibiting protein-protein interaction between dynamin-related protein 1 (Drp1) and filamin, an actin-binding protein. Here, we found that cilnidipine and its new dihydropyridine (DHP) derivative, 1,4-DHP, which lacks Ca2+ channel-blocking action of cilnidipine, prevent the palmitic acid-induced Drp1-filamin interaction, LD accumulation and cytotoxicity of human hepatic HepG2 cells. Cilnidipine and 1,4-DHP also suppressed the LD accumulation accompanied by reducing mitochondrial contact with LD in obese model and high-fat diet-fed mouse livers. These results propose that targeting the Drp1-filamin interaction become a new strategy for the prevention or treatment of fatty liver disease.

Discovery of Novel Aryl Triazolone Dihydropyridines (ATDPs) Targeting Highly Conserved Residue W229 as Promising HIV-1 NNRTIs.

NNRTI is an important component of the highly active antiretroviral therapy (HAART), but the rapid emergence of drug resistance and poor pharmacokinetics limited their clinical application. Herein, a series of novel aryl triazolone dihydropyridines (ATDPs) were designed by structure-guided design with the aim of improving drug resistance profiles and pharmacokinetic profiles. Compound 10n (EC50 = 0.009-17.7 µM) exhibited the most active potency, being superior to or comparable to that of doravirine (DOR) against the whole tested viral panel. Molecular docking was performed to clarify the reason for its higher resistance profiles. Moreover, 10n demonstrated excellent pharmacokinetic profile (T1/2 = 5.09 h, F = 108.96%) compared that of DOR (T1/2 = 4.4 h, F = 57%). Additionally, 10n was also verified to have no in vivo acute or subacute toxicity (LD50 > 2000 mg/kg), suggesting that 10n is worth further investigation as a novel oral NNRTIs for HIV-1 therapy.

New Dihydropyridine Derivative Attenuates NF-κB Activation via Suppression of Calcium Influx in a Mouse BV-2 Microglial Cell Line.

Activated microglia contribute to many neuroinflammatory diseases in the central nervous system. In this study, we attempted to identify an anti-inflammatory compound that could suppress microglial activation. We performed high-throughput screening with a chemical library developed at our institute. We performed a luciferase assay of nuclear factor-kappa B (NF-κB) reporter stable HT22 cells and identified a compound that was confirmed to inhibit the anti-inflammatory response in BV2 microglial cells. The selected dihydropyridine derivative can suppress the expression response of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor (TNF), as well as NF-κB phosphorylation and nuclear translocation, and reduce the intracellular calcium level. Thus, our identified compound has a potential role in suppressing microglial activation and may contribute to the development of a new therapeutic molecule against neuroinflammatory diseases.

The role of T-type calcium channels in elderly human vascular function: A pilot randomized controlled trial.

Endothelial dysfunction develops with age and may precede cardiovascular disease. Animal data suggest that T-type calcium channels play an important role in endothelial function, but data from humans are lacking. This study included 15 healthy, sedentary, elderly males for a double blinded, randomized controlled trial. For 8 weeks, they were given 40 mg/day of either efonidipine (L- and T-type calcium channel blocker (CCB)) or nifedipine (L-type CCB). Vascular function was evaluated by graded femoral arterial infusions of acetylcholine (ACh; endothelium-dependent vasodilator) and sodium nitroprusside (endothelium-independent vasodilator) both with and without co-infusion of N-acetylcysteine (NAC; antioxidant). We measured leg blood flow and mean arterial pressure and calculated leg vascular conductance to evaluate the leg vascular responses. Despite no significant change in blood pressure in either group, we observed higher leg blood flow responses (Δ 0.43 ± 0.45 l/min, P = 0.006) and leg vascular conductance (Δ 5.38 ± 5.67 ml/min/mmHg, P = 0.005) to intra-arterial ACh after efonidipine, whereas there was no change in the nifedipine group, and no differences between groups. We found no upregulation of endothelial nitric oxide synthase in vastus lateralis muscle biopsies within or between groups. Smooth muscle cell responsiveness was unaltered by efonidipine or nifedipine. Intravenous co-infusion of NAC did not affect endothelium-dependent vasodilatation in either of the CCB groups. These results suggest that 8 weeks' inhibition of T- and L-type calcium channels augments endothelium-dependent vasodilatory function in healthy elderly males. Further studies are required to elucidate if T-type calcium channel inhibition can counteract endothelial dysfunction.

Design, Synthesis and In-Silico Studies of Piperidine-Dihydropyridine Hybrids as Anticancer Agents.

In this study, we designed, synthesized and characterized a novel series of piperidine-dihydropyridine hybrid compounds and characterized them by 1H-NMR, 13C NMR, mass spectrometry (MS), and elemental analysis. Subsequently, we assessed their in vitro anticancer potentials against the human breast adenocarcinoma cell line MCF-7 and the lung cancer cell line A-549. Several of these compounds demonstrated significant activity, with IC50 values ranging from 15.94 µM to 48.04 µM for A-549 and 24.68 µM to 59.12 µM for MCF-7, when compared to the reference drug Cisplatin.Notably, a compound featuring a 3-fluoro substitution in the carboxamide series exhibited robust inhibitory effects, with an IC50 of 15.94±0.201 µM against A-549 cells and an IC50 of 22.12±0.213 µM against MCF-7 cells, respectively. Additionally, a compound containing a cyclobutyl ring displayed potent activity, with an IC50 of 16.56±0.125 µM against A-549 and an IC50 of 24.68±0.217 µM against MCF-7 cells, respectively. Furthermore, molecular docking studies against the Epidermal Growth Factor Receptor (EGFR) (PDB ID: 2J6M) revealed favourable binding scores and interactions, suggesting their potential as promising candidates for further investigation in the context of anticancer drug development.

Anti-inflammatory activity of benidipine hydrochloride in LPS-activated mammalian macrophages.

Benidipine hydrochloride (BH), a medication frequently used by the hypertension patients, acts as a calcium channel blocker. However, its effects on the macrophages have not been investigated thus far. Our goal was investigating the effect of the benidipine hydrochloride to modulate the J774.2 murine macrophage cells inflammatory activity. Our results suggest that in the absence of a standard stimulating agent (LPS) BH did not stimulate the macrophages to produce pro-inflammatory IL-12p40, TNF-α, GM-CSF and IL-6 cytokines. However, when BH was administrated to the cells in the presence of LPS as stimulating agent, it reduced the production of these pro-inflammatory cytokines. Therefore, it had anti-inflammatory activity. At the clinical setting this study suggests that BH can be utilized as hypertension drug that can suppress the inflammation associated with it.

Benidipine calcium channel blocker promotes the death of cigarette smoke-induced senescent cells and improves lung emphysema.

Smoking is the main risk factor for many lung diseases including chronic obstructive pulmonary disease. Cigarette smoke (CS) contains carcinogenic and reactive oxygen species that favor DNA mutations and perturb the homeostasis and environment of cells. CS induces lung cell senescence resulting in a stable proliferation arrest and a senescence-associated secretory phenotype. It was recently reported that senescent cell accumulation promotes several lung diseases. In this study, we performed a chemical screen, using an FDA-approved drug library, to identify compounds selectively promoting the death of CS-induced senescent lung cells. Aside from the well-known senolytic, ABT-263, we identified other potentially new senescence-eliminating compounds, including a new class of molecules, the dihydropyridine family of calcium voltage-gated channel (CaV) blockers. Among these blockers, Benidipine, decreased senescent lung cells and ameliorates lung emphysema in a mouse model. The dihydropyridine family of CaV blockers thus constitutes a new class of senolytics that could improve lung diseases. Hence, our work paves the way for further studies on the senolytic activity of CaV blockers in different senescence contexts and age-related diseases.

Cardioprotective Effect against Ischemia-Reperfusion Injury of PAK-200, a Dihydropyridine Analog with an Inhibitory Effect on Cl- but Not Ca2+ Current.

We examined the effects of a dihydropyridine analog, PAK-200, on guinea pig myocardium during experimental ischemia and reperfusion. In isolated ventricular cardiomyocytes, PAK-200 (1 µM) had no effect on the basal peak inward and steady-state currents but inhibited the isoprenaline-induced time-independent Cl- current. In the right atria, PAK-200 had no effect on the beating rate and the chronotropic response to isoprenaline. In an ischemia-reperfusion model with coronary-perfused right ventricular tissue, a decrease in contractile force and a rise in tension were observed during a period of 30-min no-flow ischemia. Upon reperfusion, contractile force returned to less than 50% of preischemic values. PAK-200 had no effect on the decline in contractile force during the no-flow ischemia but reduced the rise in resting tension. PAK-200 significantly improved the recovery of contractile force after reperfusion to about 70% of the preischemic value. PAK-200 was also shown to attenuate the decrease in tissue ATP during ischemia. Treatment of ventricular myocytes with an ischemia-mimetic solution resulted in depolarization of the mitochondrial membrane potential and an increase in cytoplasmic and mitochondrial Ca2+ concentrations. PAK-200 significantly delayed these changes. Thus, PAK-200 inhibits the cAMP-activated chloride current in cardiac muscle and may have protective effects against ischemia-reperfusion injury through novel mechanisms.

Synthesis, Cytotoxic Activity and In Silico Study of Novel Dihydropyridine Carboxylic Acids Derivatives.

To aid the possible prevention of multidrug resistance in tumors and cause lower toxicity, a set of sixteen novel dihydropyridine carboxylic acids derivatives 3a-p were produced; thus, the activation of various ynones with triflic anhydride was performed, involving a nucleophilic addition of several bis(trimethylsilyl) ketene acetals, achieving good yields requiring easy workup. The target molecules were unequivocally characterized by common spectroscopic methods. In addition, two of the tested compounds (3a, and 3b) were selected to perform in silico studies due to the highest cytotoxic activity towards the HCT-15 cell line (7.94 ± 1.6 µM and 9.24 ± 0.9 µM, respectively). Employing theoretical calculations with density functional theory (DFT) using the B3LYP/6-311++G(d,p) showed that the molecular parameters correlate adequately with the experimental results. In contrast, predictions employing Osiris Property Explorer showed that compounds 3a and 3b present physicochemical characteristics that would likely make it an orally active drug. Moreover, the performance of Docking studies with proteins related to the apoptosis pathway allowed a proposal of which compounds could interact with PARP-1 protein. Pondering the obtained results (synthesis, in silico, and cytotoxic activity) of the target compounds, they can be judged as suitable antineoplastic agent candidates.

A Reappraisal of the Effects of L-type Ca2+ Channel Blockers on Store-Operated Ca2+ Entry and Heart Failure.

Dihydropyridines such as amlodipine are widely used as antihypertensive agents, being prescribed to ∼70 million Americans and >0.4 billion adults worldwide. Dihydropyridines block voltage-gated Ca2+ channels in resistance vessels, leading to vasodilation and a reduction in blood pressure. Various meta-analyses show that dihydropyridines are relatively safe and effective in reducing hypertension. The use of dihydropyridines has recently been called into question as these drugs appear to activate store-operated Ca2+ entry in fura-2-loaded nonexcitable cells, trigger vascular remodeling, and increase heart failure, leading to the questioning of their clinical use. Given that hypertension is the dominant "silent killer" across the globe affecting ∼1.13 billion people, removal of Ca2+ channel blockers as antihypertensive agents has major health implications. Here, we show that amlodipine has marked intrinsic fluorescence, which further increases considerably inside cells over an identical excitation spectrum as fura-2, confounding the ability to measure cytosolic Ca2+. Using longer wavelength Ca2+ indicators, we find that concentrations of Ca2+ channel blockers that match therapeutic levels in serum of patients do not activate store-operated Ca2+ entry. Antihypertensive Ca2+ channel blockers at pharmacological concentrations either have no effect on store-operated channels, activate them indirectly through store depletion or inhibit the channels. Importantly, a meta-analysis of published clinical trials and a prospective real-world analysis of patients prescribed single antihypertensive agents for 6 mo and followed up 1 yr later both show that dihydropyridines are not associated with increased heart failure or other cardiovascular disorders. Removal of dihydropyridines for treatment of hypertension cannot therefore be recommended.

Calcium channel blocker use and outcomes in patients with heart failure and mildly reduced and preserved ejection fraction.

AIMS: Patients with heart failure (HF) and mildly reduced ejection fraction (HFmrEF) and preserved ejection fraction (HFpEF) are often treated with calcium channel blockers (CCBs), although the safety of CCBs in these patients is uncertain. We aimed to investigate the association between CCB use and clinical outcomes in patients with HFmrEF/HFpEF; CCBs were examined overall, as well as by subtype (dihydropyridine and non-dihydropyridine). METHODS AND RESULTS: We pooled individual patient data from four large HFpEF/HFmrEF trials. The association between CCB use and outcomes was assessed. Among the 16 954 patients included, the mean left ventricular ejection fraction (LVEF) was 56.8%, and 13 402 (79.0%) had HFpEF (LVEF ≥50%). Altogether, 5874 patients (34.6%) received a CCB (87.6% dihydropyridines). Overall, the risks of death and HF hospitalization were not higher in patients treated with a CCB, particularly dihydropyridines. The risk of pump failure death was significantly lower (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.60-0.96), while the risk of stroke was higher (HR 1.26, 95% CI 1.06-1.50) in patients treated with a CCB compared to those not. These risks remained different in patients treated and not treated with a CCB after adjustment for other prognostic variables. Although the majority of patients were treated with dihydropyridine CCBs, the pattern of outcomes was broadly similar for both dihydropyridine and non-dihydropyridine CCBs. CONCLUSION: Although this is an observational analysis of non-randomized treatment, there was no suggestion that CCBs were associated with worse HF outcomes. Indeed, CCB use was associated with a lower incidence of pump failure death.

Simple dihydropyridine-based colorimetric chemosensors for heavy metal ion detection, biological evaluation, molecular docking, and ADMET profiling.

In this study, two novel chemosensors containing dihydropyridine fragment namely; (2E, 2E')-1,1'-(2,6-dimethyl-1,4-dihydropyridine-3,5-diyl)bis(3-(4-(dimethylamino)phenyl)prop-2-en-1-one) (1), (2E,2E',4E,4E')-1,1' -(2,6-dimethyl-1,4-dihydropyridine-3,5-diyl)bis(5-(4-(dimethylamino)phenyl)penta-2,4-dien-1-one) (2) have been synthesized and characterized. The solvatochromic behavior was explored in different solvents of various polarities. The visual detection, as well as UV-Vis and fluorescence measurements were carried out to explore the colorimetric and optical sensing properties of the investigated chemosensors towards various metal ions such as Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Mg2+, Hg2+ and Zn2+. The chemosensors 1 and 2 have strong detecting abilities, with excellent sensitivity and selectivity for Cu2+ and Fe3+, respectively, over the other metal ions. The chemosensors were totally reversible upon addition of EDTA to the formed complexes and displayed a turn on-off-on fluorescence response based on an effect of chelation-quenching fluorescence. The antioxidant activities of the investigated chemosensors were assessed. They were examined in-silico for their capacity to block the Akt signaling pathway, which is involved in cancer proliferation with interpreting their pharmacokinetics aspects. Furthermore, in-vitro antitumor evaluation against a panel of cancer cell lines for the investigated chemosensors has been examined. Conclusively, chemosensor 1 was more effective at scavenging free radicals and as an anticancer agent and could be exploited as a therapeutic candidate for cancer therapy than chemosensor 2 due to its potential inhibition of Akt protein.

Mechanisms of dihydropyridine agonists and antagonists in view of cryo-EM structures of calcium and sodium channels.

Opposite effects of 1,4-dihydropyridine (DHP) agonists and antagonists on the L-type calcium channels are a challenging problem. Cryo-EM structures visualized DHPs between the pore-lining helices S6III and S6IV in agreement with published mutational data. However, the channel conformations in the presence of DHP agonists and antagonists are virtually the same, and the mechanisms of the ligands' action remain unclear. We docked the DHP agonist S-Bay k 8644 and antagonist R-Bay k 8644 in Cav1.1 channel models with or without π-bulges in helices S6III and S6IV. Cryo-EM structures of the DHP-bound Cav1.1 channel show a π-bulge in helix S6III but not in S6IV. The antagonist's hydrophobic group fits into the hydrophobic pocket formed by residues in S6IV. The agonists' polar NO2 group is too small to fill up the pocket. A water molecule could sterically fit into the void space, but its contacts with isoleucine in helix S6IV (motif INLF) would be unfavorable. In a model with π-bulged S6IV, this isoleucine turns away from the DHP molecule and its position is occupied by the asparagine from the same motif INLF. The asparagine provides favorable contacts for the water molecule at the agonist's NO2 group but unfavorable contacts for the antagonist's methoxy group. In our models, the DHP antagonist stabilizes entirely α-helical S6IV. In contrast, the DHP agonist stabilizes π-bulged helix S6IV whose C-terminal part turned and rearranged the activation-gate region. This would stabilize the open channel. Thus, agonists, but not antagonists, would promote channel opening by stabilizing π-bulged helix S6IV.

New Insights into the Nephroprotective Potential of Lercanidipine.

Kidneys are responsible for many crucial biological processes in the human body, including maintaining the water-electrolyte balance, pH, and blood pressure (BP), along with the elimination of toxins. Despite this, chronic kidney disease (CKD), which affects more and more people, is a disease that develops insidiously without causing any symptoms at first. The main purpose of this article is to summarize the existing literature on lercanidipine, with a particular focus on its nephroprotective properties. Lercanidipine is a third-generation dihydropyridine (DHP) blocker of calcium channels, and as such it possesses unique qualities such as high lipophilicity and high vascular selectivity. Furthermore, it acts by reversibly inhibiting L-type and T-type calcium channels responsible for exerting positive renal effects. It has been shown to reduce tissue inflammation and tubulointerstitial fibrosis, contributing to a decrease in proteinuria. Moreover, it exhibited antioxidative effects and increased expression of molecules responsible for repairing damaged tissues. It also decreased cell proliferation, preventing thickening of the vascular lumen. This article summarizes studies simultaneously comparing the effect of lercanidipine with other antihypertensive drugs. There is still a lack of studies on the medications used in patients with CKD, and an even greater lack of studies on those used in patients with concomitant hypertension. Therefore, further studies on lercanidipine and its potential in hypertensive patients with coexisting CKD are required.