Absorption, elimination and cerebrospinal fluid concentrations of nimodipine in healthy beagle dogs receiving human intravenous and oral formulation

Nimodipine reduces microglial activation in vitro as evidenced by morphological phenotype, phagocytic activity and high-throughput RNA sequencing

BACKGROUND AND PURPOSE

Nimodipine, an L-type voltage-gated calcium channel blocker, is an approved cerebral vasorelaxant. We hypothesized that nimodipine attenuates the pro-inflammatory shift in microglial phenotypes. Here, we analysed the effects of nimodipine on morphological and functional microglial phenotypes as well as their transcriptomic profile.

EXPERIMENTAL APPROACH

Live brain slice preparations from C57BL/6 mice and primary microglia cultures from neonatal Sprague Dawley rats were used. Microglia were activated either by ischemia or lipopolysaccharide (LPS), and preparations were treated with nimodipine (5-10-20 μM). Microglial morphological phenotypes, phagocytic activity, Iba1 expression and TNF-α levels were evaluated. Total RNA was isolated from monocultures and processed for next generation RNA sequencing.

KEY RESULTS

LPS resulted in a pro-inflammatory microglial phenotype, affecting the expression of cytokines, the complement system and phagocytosis-related genes. LPS increased the transcription of ionotropic purinergic and TRP channels but decreased the expression of voltage- and ligand-gated calcium channels, down-regulated the expression of Ryr and IP3 receptors and increased transcription of the SERCA calcium pump. Nimodipine suppressed the amoeboid morphological transformation and phagocytosis and altered the expression of 110 genes in the opposite direction to LPS activation, of which at least 20 were associated with the microglial immune response, seven with cell adhesion and two with autophagy regulation.

CONCLUSION AND IMPLICATIONS

The effect of nimodipine goes beyond cerebral vasorelaxation. Nimodipine attenuates microglial activation by modulating Ca2+-dependent gene expression involved in intracellular signalling cascades to drive microglial immune responses. Consideration should be given to expanding the use of nimodipine beyond vasorelaxation.

A Novel Targeted Nanoparticle for Traumatic Brain Injury Treatment: Combined Effect of ROS Depletion and Calcium Overload Inhibition

Survival after severe traumatic brain injury (TBI) depends on minimizing or avoiding secondary insults to the brain. Overproduction of reactive oxygen species (ROS) and Ca²⁺ influx at the damaged site are the key factors that cause secondary injury upon TBI. Herein, a TBI-targeted lipid covered radical scavenger nanoparticle is developed to deliver nimodipine (Np) (CL-PPS/Np), in order to inhibit Ca²⁺ influx in neurons by Np and to scavenge ROS in the brain trauma microenvironment by poly(propylene sulfide)₆₀ (PPS₆₀ ) and thus prevent TBI-associated secondary injury. In post-TBI models, CL-PPS/Np effectively accumulates into the wound cavity and prolongs the time of systemic circulation of Np. CL-PPS/Np can markedly protect the integrity of blood-brain barrier, prevent brain edema, reduce cell death and inflammatory responses, and promote functional recovery after TBI. These findings may provide a new therapy for TBI to prevent the spread of the secondary injury.

Influence of nimodipine combined with ulinastatin on neurological function and inflammatory reaction in patients with cerebral vasospasm after subarachnoid hemorrhage

OBJECTIVE

This study aimed to discuss the influence of nimodipine+ulinastatin on the neurological function and inflammatory reaction in patients with cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH).

METHODS

Overall, 90 patients with CVS after SAH who were admitted to our hospital were enrolled in this study and randomly divided into research and control groups (n = 45 for both groups). On the basis of conventional therapy, patients in the control group were injected with ulinastatin and those in the research group were injected with ulinastatin+nimodipine through an intravenous drip for 7 days with the others the same as those of the control group.

RESULTS

Blood flow velocity in all cerebral arteries was lower in the research group than in the control group after treatment (P < 0.05). Calcitonin gene-related peptide and nitric oxide levels were higher in the research group than in the control group after treatment (P < 0.05). Endothelin levels were lower in the research group than in the control group (P < 0.05). The total effective rate was higher in the research group than in the control group (P < 0.05). Glasgow Coma Scale scores were higher in the research group than in the control group (P < 0.05).

CONCLUSION

The drug combination of nimodipine and ulinastatin improved blood flow and neurological function in patients with CVS after SAH and enhanced the therapeutic efficacy; the underlying mechanism may be associated with the regulation of vascular endothelial dilatation function and the inhibition of relevant inflammatory factors' expression.

Comparative Pharmacokinetics of Nimodipine in Rat Plasma and Tissues Following Intraocular, Intragastric, and Intravenous Administration

We investigated the pharmacokinetics of nimodipine (NMD) in rats plasma and tissues following intraocular (io), intragastric (ig), and intravenous (iv) administration at doses of 5.0 mg/kg io and iv and 10.0 mg/kg ig. After a single dose of NMD, plasma, heart, liver, spleen, lung, kidney, and brain samples were collected at the scheduled time points. The concentration of NMD in rat plasma and tissues was determined by high-performance liquid chromatography, and the main pharmacokinetic parameters were calculated and compared. NMD was rapidly absorbed and reached the maximum plasma concentration in approximately 5 min after io administration. The absolute bioavailability after io administration was higher than that after ig administration (40.05% vs. 5.67%). There were significant differences in the tissue distribution of NMD with different administration routes. After io administration, NMD was distributed more in the lung, spleen, and brain tissues, and less in the kidney. The maximum drug concentration after io administration in the heart, liver, spleen, lung, kidney, and brain was 1.00, 0.47, 2.02, 1.47, 0.22, and 5.79 times higher than that after via ig administration, and the area under the curve value was 0.59, 0.78, 1.71, 1.84, 0.25, and 4.59 times greater, respectively. Nimodipine appears to achieve systemic effects via io administration. Compared with ig, io administration could significantly increase NMD distribution in the brain tissue, indicating that NMD could be delivered to the brain via io administration.

Nimodipine treatment does not benefit juvenile ferrets with kaolin-induced hydrocephalus

Prior research on 3-week hydrocephalic rats showed that behavioral deficits and white matter damage could be reduced by treatment with Ca²⁺ channel blocker nimodipine. We hypothesized that treatment with nimodipine would be also beneficial to young ferrets with kaolin-induced hydrocephalus. Hydrocephalus was induced at 14 days of age and animals were treated either with vehicle, low dose nimodipine (3.2 mg/kg/day), or high dose nimodipine (16 mg/kg/day) for 2 weeks from 38 to 52 days age. Hydrocephalic ferrets developed progressive ventriculomegaly, behavioral changes, and in some cases cortical blindness. These changes were not ameliorated by nimodipine. Histological examination showed damage in periventricular white matter, corpus callosum thinning, axonal damage, reactive astroglial changes, and suppressed cell proliferation compared to non-hydrocephalic controls. Treatment with nimodipine was not beneficial for any of the pathological changes mentioned above; only low dose nimodipine treatment was associated with normalized content of glial fibrillary acidic protein, despite larger ventricles. We conclude that young hydrocephalic ferrets experience behavioral impairments and structural brain damage that are not consistently improved by intermittent nimodipine treatment. Continuous delivery should be considered in further preclinical studies.