sb-3ct-compound and Brain-Injuries

SB-3CT is a potent and selective inhibitor of matrix metalloproteinase (MMP)-2 and -9, which has shown efficacy in an animal model of severe traumatic brain injury (TBI). However, SB-3CT is poorly water-soluble and is metabolized primarily to p-hydroxy SB-3CT (2), a more potent inhibitor than SB-3CT. We synthesized the O-phosphate prodrug (3) of compound 2 to enhance its water solubility by more than 2000-fold. The prodrug 3 was a poor MMP inhibitor, but readily hydrolyzed to the active 2 in human blood. Pharmacokinetics and brain distribution studies in mice showed that 2 crossed the blood-brain barrier (BBB) and achieved therapeutic concentrations in the brain. The prodrug 3/compound 2 was evaluated in a mouse model of severe TBI and found to significantly decrease the brain lesion volume and improve neurological outcomes. MMP-9 inhibition by a water-soluble thiirane inhibitor is a promising therapy for treatment of TBI.

Topics: Animals; Area Under Curve; Blood-Brain Barrier; Brain Injuries; Cell Line; Disease Models, Animal; Dose-Response Relationship, Drug; Heterocyclic Compounds, 1-Ring; Inhibitory Concentration 50; Male; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Mice; Mice, Inbred C57BL; Neurologic Examination; Psychomotor Performance; Solubility; Sulfones; Water

The gelatinases, matrix metalloproteinases (MMP)-2 and MMP-9, are thought to be key mediators of secondary damage in adult animal models of brain injury. Moreover, an acute increase in these proteases in plasma and brain extracellular fluid of adult patients with moderate-to-severe traumatic brain injuries (TBIs) is associated with poorer clinical outcomes and mortality. Nonetheless, their involvement after TBI in the pediatric brain remains understudied. Using a murine model of TBI at postnatal day 21 (p21), approximating a toddler-aged child, we saw upregulation of active and pro-MMP-9 and MMP-2 by gelatin zymography at 48 h post-injury. We therefore investigated the role of gelatinases on long-term structural and behavioral outcomes after injury after acute inhibition with a selective gelatinase inhibitor, p-OH SB-3CT. After systemic administration, p-OH SB-3CT crossed the blood-brain barrier at therapeutically-relevant concentrations. TBI at p21 induced hyperactivity, deficits in spatial learning and memory, and reduced sociability when mice were assessed at adulthood, alongside pronounced tissue loss in key neuroanatomical regions. Acute and short-term post-injury treatment with p-OH SB-3CT did not ameliorate these long-term behavioral, cognitive, or neuropathological deficits as compared to vehicle-treated controls, suggesting that these deficits were independent of MMP-9 and MMP-2 upregulation. These findings emphasize the vulnerability of the immature brain to the consequences of traumatic injuries. However, early upregulation of gelatinases do not appear to be key determinants of long-term recovery after an early-life injury.

Topics: Animals; Biological Transport; Blood-Brain Barrier; Brain Injuries; Child, Preschool; Disease Models, Animal; Gene Expression; Heterocyclic Compounds, 1-Ring; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Maze Learning; Mice; Mice, Inbred C57BL; Prognosis; Recovery of Function; Social Isolation; Spatial Memory; Sulfones; Trauma Severity Indices; Treatment Failure

The aim of this study was to evaluate the potential efficacy of SB-3CT, a matrix metallopeptidase 9 inhibitor, on behavioral and histological outcomes after traumatic brain injury (TBI) in rats. Adult male Sprague-Dawley rats were randomly divided into three groups (n=15/group): TBI with SB-3CT treatment, TBI with saline, and sham injury. The TBI model was induced by a fluid percussion TBI device. SB-3CT (50 mg/kg in 10% dimethyl sulfoxide) was administered intraperitoneally at 30 min, 6 h, and 12 h after the TBI. Motor function (beam-balance/beam-walk tests) and spatial learning/memory (Morris water maze) were assessed on post-operative Days 1-5 and 11-15, respectively. Fluoro-Jade staining, immunofluorescence, and cresyl violet-staining were carried out for histopathological evaluation at 24 h, 72 h, and 15 days after TBI, respectively. It was shown that TBI can result in significant behavioral deficit induced by acute neurodegeneration, increased expression of cleaved caspase-3, and long-term neuronal loss. SB-3CT intervention via the current regime provides robust behavioral protection and hippocampal neurons preservation from the deleterious effects of TBI. Hence, the efficacy of SB-3CT on TBI prognosis could be ascertained. It is believed that the current study adds to the growing literature in identifying SB-3CT as a potential therapy for human brain injury.

Topics: Animals; Brain Injuries; Heterocyclic Compounds, 1-Ring; Hippocampus; Male; Matrix Metalloproteinase 9; Maze Learning; Motor Skills; Random Allocation; Rats; Rats, Sprague-Dawley; Sulfones

Traumatic brain injury (TBI) is a leading cause of death and long-term disability. Following the initial insult, severe TBI progresses to a secondary injury phase associated with biochemical and cellular changes. The secondary injury is thought to be responsible for the development of many of the neurological deficits observed after TBI and also provides a window of opportunity for therapeutic intervention. Matrix metalloproteinase-9 (MMP-9 or gelatinase B) expression is elevated in neurological diseases and its activation is an important factor in detrimental outcomes including excitotoxicity, mitochondrial dysfunction and apoptosis, and increases in inflammatory responses and astrogliosis. In this study, we used an experimental mouse model of TBI to examine the role of MMP-9 and the therapeutic potential of SB-3CT, a mechanism-based gelatinase selective inhibitor, in ameliorating the secondary injury. We observed that activation of MMP-9 occurred within one day following TBI, and remained elevated for 7 days after the initial insult. SB-3CT effectively attenuated MMP-9 activity, reduced brain lesion volumes and prevented neuronal loss and dendritic degeneration. Pharmacokinetic studies revealed that SB-3CT and its active metabolite, p-OH SB-3CT, were rapidly absorbed and distributed to the brain. Moreover, SB-3CT treatment mitigated microglial activation and astrogliosis after TBI. Importantly, SB-3CT treatment improved long-term neurobehavioral outcomes, including sensorimotor function, and hippocampus-associated spatial learning and memory. These results demonstrate that MMP-9 is a key target for therapy to attenuate secondary injury cascades and that this class of mechanism-based gelatinase inhibitor-with such desirable pharmacokinetic properties-holds considerable promise as a potential pharmacological treatment of TBI.

Topics: Analysis of Variance; Animals; Blood-Brain Barrier; Brain; Brain Injuries; Enzyme Activation; Fluorescence; Heterocyclic Compounds, 1-Ring; Histological Techniques; Immunohistochemistry; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Maze Learning; Mice; Sulfones

This study investigated the role of matrix metalloproteinase-9 (MMP-9) in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Sprague-Dawley male rats (n=30) between 250 and 300 g were used. SAH was produced by injecting autologous arterial blood into the prechiasmatic cistern. SB-3CT, a selective MMP-9 inhibitor, was injected intraperitoneally after SAH induction. MMP-9 protein expression was measured by western blot; laminin expression and neuronal cells in the cerebral cortex were studied by immunohistochemistry and TUNEL staining at 24h after SAH. MMP-9 expression was increased after SAH and decreased by SB-3CT inhibition at 24h after SAH (P<0.01). Laminin, the substrate of MMP-9, was decreased at 24h after SAH, and SB-3CT prevented laminin degradation. The number of TUNEL-positive neurons in cerebral cortex was increased after SAH and decreased by SB-3CT (P<0.01). MMP-9 may be involved in EBI after SAH and inhibition of MMP-9 may reduce EBI in cerebral cortex.

Topics: Analysis of Variance; Animals; Brain Injuries; Cerebral Cortex; Disease Models, Animal; Down-Regulation; Enzyme Inhibitors; Heterocyclic Compounds, 1-Ring; In Situ Nick-End Labeling; Laminin; Male; Matrix Metalloproteinase 9; Neurons; Rats; Rats, Sprague-Dawley; Subarachnoid Hemorrhage; Sulfones