Effects of a novel antihypertensive drug, cilnidipine, on catecholamine secretion from differentiated PC12 cells

Inhibition of Sympathetic Activation by Delivering Calcium Channel Blockers from a 3D Printed Scaffold to Promote Bone Defect Repair

Enhancing osteogenesis by promoting neural network reconstruction and neuropeptide release is considered to be an attractive strategy for repairing of critical size bone defects. However, traumatic bone defects often activate the damaged sympathetic nervous system (SNS) in the defect area and release excessive catecholamine to hinder bone defect repair. Herein, a 3D printed scaffold loaded with the calcium channel blocker-nifedipine is proposed to reduce the concentration of catecholamine present in the bone defect region and to accelerate bone healing. To this end, nifedipine-loaded ethosome and laponite are added into a mixed solution containing sodium alginate, methacrylated gelatin, and bone mesenchymal stem cells (BMSCs) to prepare a cell-laden scaffold using 3D bioprinting. The released nifedipine is able to close the calcium channels of nerve cells, thereby blocking sympathetic activation and ultimately inhibiting the release of catecholamine by sympathetic nerve cells, which further promotes the osteogenic differentiation and migration of BMSCs, inhibits osteoclastogenesis in vitro, and effectively improves bone regeneration in a rat critical-size calvarial defect model. Therefore, the results suggest that sustained release of nifedipine from the scaffold can effectively block SNS activation, providing promising strategies for future treatment of bone defects.

Switching to an L/N-type calcium channel blocker shows renoprotective effects in patients with chronic kidney disease: the Kyoto Cilnidipine Study

OBJECTIVE

This open-label, randomized controlled trial investigated the effects of cilnidipine, an L/N-type calcium channel blocker (CCB), in patients with chronic kidney disease (CKD).

METHODS

Sixty patients with CKD and well-controlled hypertension being treated with a renin- angiotensin system (RAS) inhibitor and an L-type CCB (L-CCB) were randomly assigned either to switch from the L-CCB to cilnidipine after a 4-week observation period or to continue with L-CCB treatment. Blood pressure, heart rate and renal function were monitored for 12 months. Data were available for analysis from 50 patients: 24 from the cilnidipine group and 26 from the L-CCB group.

RESULTS

Blood pressure was well controlled in both groups. After 12 months, proteinuria and heart rate were significantly decreased in the cilnidipine group, but proteinuria increased and heart rate remained unchanged in the L-CCB group. There was a significant positive correlation between the percentage changes in proteinuria and heart rate.

CONCLUSIONS

Cilnidipine has antihypertensive effects equivalent to those of L-CCBs. In patients with CKD, proteinuria can be decreased by switching from an L-CCB to cilnidipine, thereby improving renal function.

Effects of a dual L/N-type calcium channel blocker cilnidipine on blood pressure, pulse rate, and autonomic functions in patients with mild to moderate hypertension

The current study was conducted to examine the effects of cilnidipine, a dual L/N-type calcium channel blocker, on blood pressure, pulse rate, and autonomic functions in patients with mild-to-moderate hypertension. Sixteen patients with mild-to-moderate hypertension (8 males and 8 females; 44-72 years of age) were treated with cilnidipine (10 mg/day) for 3 months. Before and after the treatment, the following measurements were conducted; beat-to-beat blood pressure during late phase II and overshoot phase of the Valsalva maneuver, the Valsalva ratio, heart rate response to deep breathing, systolic and diastolic blood pressure, and pulse rate. The head-up tilt test was also performed before and after the treatment. Cilnidipine significantly decreased either the systolic or diastolic blood pressure from 151 +/- 15 mmHg to 129 +/- 14 mmHg or 84 +/- 11 mmHg to 71 +/- 9 mmHg, respectively. For pulse rate, there were no significant changes during therapy. Beat-to-beat blood pressure during late phase II and overshoot phase of the Valsalva maneuver indicated significant improvements in both figures. The heart rate response to deep breathing and the Valsalva ratio indicated no significant differences during therapy. Before and after the treatment, no orthostatic hypotension was observed during the head-up tilt test. The current study revealed that cilnidipine significantly decreases blood pressure with improving autonomic functions while having no adverse effects on heart rate response and pulse rate.

Effects of Calcium Channel Antagonists on Left Ventricular Hypertrophy and Diastolic Function in Patients with Essential Hypertension

Hypertensive patients characteristically exhibit left ventricular (LV) hypertrophy and diastolic dysfunction. The effects of antihypertensive agents on LV hypertrophy and diastolic dysfunction do not always correlate with the degree of blood pressure reduction, but their effects on the sympathetic nervous system and renin-angiotensin system (RA system) are thought to be important. We investigated the effects of amlodipine and cilnidipine, N- and L-type calcium channel antagonists that suppress both blood pressure elevation and sympathetic activities, on LV hypertrophy and diastolic function. Patients with essential hypertension were randomly assigned to receive either amlodipine, cilnidipine or nifedipine CR (which does not block N-type calcium channels) for 6 months. The LV mass index was determined using M-mode echocardiography. The E/A ratio, i.e., the ratio of maximum amplitude between the early diastolic wave (E wave) and the atrial systolic wave (A wave) in the LV inflow pattern, and the deceleration time for the E wave were determined using pulse Doppler echocardiography. Systolic and diastolic blood pressures significantly decreased from the baseline values in all three groups, with no significant differences among the groups. The LV mass index had significantly decreased when it was evaluated 3 months after the initiation of treatment in the cilnidipine group and when it was evaluated 6 months after the initiation of treatment in the amlodipine group; only a slight decrease was observed in the nifedipine CR group. A significant decrease in the deceleration time and a significant increase in the E/A ratio were observed after 3 months of treatment in the cilnidipine and amlodipine groups but not in the nifedipine CR group. Thus, the effects of long-acting calcium channel antagonists on hypertensive LV hypertrophy and LV diastolic function varied from one antagonist to the other. Left ventricular hypertrophy and diastolic function improved in the cilnidipine and amlodipine groups, but not in the nifedipine CR group. These results indicate that the suppression of sympathetic nerve activity by the blockade of N-type calcium channels contributes to the improvement of LV hypertrophy and diastolic function.

Neuronal Ca2+ Channel Blocking Action of an Antihypertensive Drug, Cilnidipine, in IMR-32 Human Neuroblastoma Cells

Although the anti-sympathetic mechanisms of the antihypertensive drug cilnidipine have been analyzed in neuronal cells derived from rodents, there is little information regarding the effects of cilnidipine in human neuronal cells. We investigated the effects of cilnidipine on N-type Ca2+ channels in IMR-32 human neuroblastoma cells using fura-2-based microfluorimetry. The ratio of the intensities of the emitted fluorescence at an excitation wavelength of 340 nm to that at 380 nm was calibrated to estimate the intracellular concentration of Ca2+. Stimulation of IMR-32 cells by 40 mmol/l KCl immediately increased the intensities ratio. In the presence of 10 micromol/l of nifedipine to block L-type Ca2+ channels, omega-conotoxin GVIA, a selective N-type Ca2+ channel blocker, in a concentration of 1 micromol/l suppressed the elevation of the intensities ratio induced by 40 mmol/l KCl. Similarly, cilnidipine in a concentration of 10 micromo/l suppressed the elevation of the ratio induced by 40 mmol/l KCl, and this suppression was effectively inhibited after the treatment with omega-conotoxin GVIA. These results suggest that cilnidipine potentially inhibits N-type Ca2+ channels in human neuronal cells and might be applied as a prospective therapeutic tool to provide neuronal protection as well as its antihypertensive effects and anti-sympathetic actions.

Inhibitory effects of cilnidipine on peripheral and brain N-type Ca2+ channels expressed in BHK cells

We investigated differences in electrophysiological characteristics between peripheral and central N-type Ca(2+) channels, containing alpha(1B-a) and a(1B-c), respectively. In addition, we examined the inhibitory effects of cilnidipine, a dihydropyridine (DHP) derivative, on both channels. Both alpha(1B) subunits were transiently expressed in BHK cells, and then analyzed using the whole-cell patch-clamp technique. The current-voltage relationship showed that alpha(1B-c) currents were activated at more negative potentials than alpha(1B-a) currents. The voltage-dependent steady-state inactivation and activation showed that the V(1/2) values for inactivation and activation of alpha(1B-c) (-88.5+/-1.3 and -33.2+/-1.3 mV) were both significantly more negative than those for alpha(1B-a) (-83.3+/-1.3 and -27.9+/-2.3 mV). Despite the different electrophysiological characteristics of these two N-type channels, cilnidipine blocked both with similar potency within the range 0.1 to 10 microM. Furthermore, cilnidipine had no effect on the I-V relationships or the steady-state inactivation curves. Our data indicate that the spliced positions of alpha(1B-a) and a(1B-c) may affect not only their voltage-sensing abilities but also the kinetics of channel activation and inactivation. The data also suggest that cilnidipine binds to sites independent of those controlling voltage-sensing and channel kinetics in these alpha(1B) subunits.

Selectivity of dihydropyridines for cardiac L-type and sympathetic N-type Ca2+ channels

The blocking effects of cilnidipine and other dihydropyridines on L-type cardiac Ca2+ channels (I(Ca,L)) and N-type sympathetic Ca2+ channel currents (I(Ca,N)) were studied using a whole-cell patch-clamp technique. At -80 mV, cilnidipine had little inhibitory effect below concentrations of 1 microM on I(Ca,L) (IC50 value; 17 microM). However, 1 microM cilnidipine strongly shifted the steady-state inactivation curve of I(Ca,L) toward negative potentials without changing the current-voltage relationship. Each action of cilnidipine was characterized by a high affinity for the inactivated channel in preference to the resting channel. The IC50 values of dihydropyridines for I(Ca,L) were in the range between 0.01 and 10 microM, and those for I(Ca,N) were between 3 and 30 microM. Cilnidipine had the strongest affinity for I(Ca,N) among the dihydropyridines tested. These results suggest that cilnidipine did not cause hypotension-evoked tachycardia deficiency by depression of cardiac L-type channels but by sympathetic N-type channels blockade.