The matrix metalloproteinase inhibitor marimastat inhibits seizures in a model of kainic acid-induced status epilepticus.

An intra-hippocampus injection of kainic acid serves as a model of status epilepticus and the subsequent development of temporal lobe epilepsy. Matrix metalloproteinase-9 (MMP-9) is an enzyme that controls remodeling of the extracellular milieu under physiological and pathological conditions. In response to brain insult, MMP-9 contributes to pathological synaptic plasticity that may play a role in the progression of an epileptic condition. Marimastat is a metalloproteinase inhibitor that was tested in clinical trials of cancer. The present study assessed whether marimastat can impair the development of epilepsy. The inhibitory efficacy of marimastat was initially tested in neuronal cultures in vitro. As a marker substrate, we used nectin-3. Next, we investigated the blood-brain barrier penetration of marimastat using mass spectrometry and evaluated the therapeutic potential of marimastat against seizure outcomes. We found that marimastat inhibited the cleavage of nectin-3 in hippocampal neuronal cell cultures. Marimastat penetrated the blood-brain barrier and exerted an inhibitory effect on metalloproteinase activity in the brain. Finally, marimastat decreased some seizure parameters, such as seizure score and number, but did not directly affect status epilepticus. The long-term effects of marimastat were evident up to 6 weeks after kainic acid administration, in which marimastat still inhibited seizure duration.

A Simple Adaptable Blood-Brain Barrier Cell Model for Screening Matrix Metalloproteinase Inhibitor Functionality.

The blood-brain barrier is a multicellular and basement membrane unit that regulates molecular transport between the blood and central nervous system. Many cerebral pathologies, such as acute stroke and chronic vascular dementia, result in a disrupted blood-brain barrier, increasing its permeability and allowing the entry of potentially neurotoxic molecules. The activation of matrix metalloproteinases mediates further blood-brain barrier damage. The inhibition of matrix metalloproteinases is a potential strategy for stroke therapy. As inhibitors are developed, efficient context-specific screening methods will be required. Models of the blood-brain barrier have been extensively used to study neuropathologies and the effect of various treatment options.Herein, we describe a co-culture model of the blood-brain barrier composed of brain microvascular endothelial cells and astrocytes grown on an artificial basement membrane-coated membrane insert. Our cell model forms a barrier and is a simple first approximation of blood-brain barrier integrity. As currently developed, the model may be applied to testing the effect of matrix metalloproteinases and matrix metalloproteinase inhibitors on blood-brain barrier physiology and pathophysiology. The model is a quick and effective evaluation tool for generating nonclinical data in a living cell system before proceeding to animal models.

Selective Inhibition of MMP-2 Does Not Alter Neurological Recovery after Spinal Cord Injury.

Matrix metalloproteinase (MMP)-2 knockout (KO) mice show impaired neurological recovery after spinal cord injury (SCI), suggesting that this proteinase is critical to recovery processes. However, this finding in the KO has been confounded by a compensatory increase in MMP-9. We synthesized the thiirane mechanism-based inhibitor ND-378 and document that it is a potent (nanomolar) and selective slow-binding inhibitor of MMP-2 that does not inhibit the closely related MMP-9 and MMP-14. ND-378 crosses the blood-spinal cord barrier, achieving therapeutic concentrations in the injured spinal cord. Spinal-cord injured mice treated with ND-378 showed no change in long-term neurological outcomes, suggesting that MMP-2 is not a key determinant of locomotor recovery.

Doxycycline-loaded ß-tricalcium phosphate release following EDTA root surface etching improved the clinical outcomes in chronic periodontitis: an in vivo study.

BACKGROUND: The main objective of the present study is to quantify doxycycline (DOX) release from ß-tricalcium phosphate (ß-TCP) after EDTA root surface treatment. METHODS: Thirty systemically healthy patients with ≥1 paired contralateral interproximal intrabony defect ≥4 mm deep along with an interproximal probing depth ≥6 mm and clinical attachment level ≥4 mm were randomized into two groups. Group 1 (G1) consisted of sites treated with open flap debridement followed by placement of DOX blended with ß-TCP (DOX-ß-TCP), whereas group 2 (G2) sites were treated with flap surgery followed by the placement of DOX blended with ß-TCP after EDTA etching of the exposed root surfaces (DOX-ß-TCP + EDTA). Samples of gingival crevicular fluid (GCF) were obtained 1, 3, 7, 14, and 21 days after surgery. Quantitative measurements of DOX were taken with high-performance liquid chromatography. Clinical evaluation and follow-up for 6 months were performed. RESULTS: At 21 days, the DOX-ß-TCP + EDTA-treated group showed a 194.7 µg/mL value. The DOX-ß-TCP + EDTA-treated group retained more DOX during the periods of 3, 7, 10, 14, and 21 days than the DOX-ß-TCP-treated group. Six months after therapy, DOX-ß-TCP + EDTA-treated sites showed more significant clinical improvements compared to DOX-ß-TCP-treated sites (P ≤ 0.05). CONCLUSIONS: EDTA root surface etching enhances DOX availability in the GCF following its release from ß-TCP as a drug carrier.