Provision of rapid and specific ex vivo diagnosis of central nervous system lymphoma from rodent xenograft biopsies by a fluorescent aptamer.

OBJECTIVE: Differentiating central nervous system (CNS) lymphoma from other intracranial malignancies remains a clinical challenge in surgical neuro-oncology. Advances in clinical fluorescence imaging contrast agents and devices may mitigate this challenge. Aptamers are a class of nanomolecules engineered to bind cellular targets with antibody-like specificity in a fraction of the staining time. Here, the authors determine if immediate ex vivo fluorescence imaging with a lymphoma-specific aptamer can rapidly and specifically diagnose xenografted orthotopic human CNS lymphoma at the time of biopsy. METHODS: The authors synthesized a fluorescent CNS lymphoma-specific aptamer by conjugating a lymphoma-specific aptamer with Alexa Fluor 488 (TD05-488). They modified human U251 glioma cells and Ramos lymphoma cells with a lentivirus for constitutive expression of red fluorescent protein and implanted them intracranially into athymic nude mice. Three to 4 weeks postimplantation, acute slices (biopsies, n = 28) from the xenografts were collected, placed in aptamer solution, and imaged with a Zeiss fluorescence microscope. Three aptamer staining concentrations (0.3, 1.0, and 3.0 µM) and three staining times (5, 10, and 20 minutes) followed by a 1-minute wash were tested. A file of randomly selected images was distributed to neurosurgeons and neuropathologists, and their ability to distinguish CNS lymphoma from negative controls was assessed. RESULTS: The three staining times and concentrations of TD05-488 were tested to determine the diagnostic accuracy of CNS lymphoma within a frozen section time frame. An 11-minute staining protocol with 1.0-µM TD05-488 was most efficient, labeling 77% of positive control lymphoma cells and less than 1% of negative control glioma cells (p < 0.001). This protocol permitted clinicians to positively identify all positive control lymphoma images without misdiagnosing negative control images from astrocytoma and normal brain. CONCLUSIONS: Ex vivo fluorescence imaging is an emerging technique for generating rapid histopathological diagnoses. Ex vivo imaging with a novel aptamer-based fluorescent nanomolecule could provide an intraoperative tumor-specific diagnosis of CNS lymphoma within 11 minutes of biopsy. Neurosurgeons and neuropathologists interpreted images generated with this molecular probe with high sensitivity and specificity. Clinical application of TD05-488 may permit specific intraoperative diagnosis of CNS lymphoma in a fraction of the time required for antibody staining.

Cyclooxygenase-2-specific inhibitor improves functional outcomes, provides neuroprotection, and reduces inflammation in a rat model of traumatic brain injury.

OBJECTIVE: Increases in brain cyclooxygenase-2 (COX2) are associated with the central inflammatory response and with delayed neuronal death, events that cause secondary insults after traumatic brain injury. A growing literature supports the benefit of COX2-specific inhibitors in treating brain injuries. METHODS: DFU [5,5-dimethyl-3(3-fluorophenyl)-4(4-methylsulfonyl)phenyl-2(5)H)-furanone] is a third-generation, highly specific COX2 enzyme inhibitor. DFU treatments (1 or 10 mg/kg intraperitoneally, twice daily for 3 d) were initiated either before or after traumatic brain injury in a lateral cortical contusion rat model. RESULTS: DFU treatments initiated 10 minutes before injury or up to 6 hours after injury enhanced functional recovery at 3 days compared with vehicle-treated controls. Significant improvements in neurological reflexes and memory were observed. DFU initiated 10 minutes before injury improved histopathology and altered eicosanoid profiles in the brain. DFU 1 mg/kg reduced the rise in prostaglandin E2 in the brain at 24 hours after injury. DFU 10 mg/kg attenuated injury-induced COX2 immunoreactivity in the cortex (24 and 72 h) and hippocampus (6 and 72 h). This treatment also decreased the total number of activated caspase-3-immunoreactive cells in the injured cortex and hippocampus, significantly reducing the number of activated caspase-3-immunoreactive neurons at 72 hours after injury. DFU 1 mg/kg amplified potentially anti-inflammatory epoxyeicosatrienoic acid levels by more than fourfold in the injured brain. DFU 10 mg/kg protected the levels of 2-arachidonoyl glycerol, a neuroprotective endocannabinoid, in the injured brain. CONCLUSION: These improvements, particularly when treatment began up to 6 hours after injury, suggest exciting neuroprotective potential for COX2 inhibitors in the treatment of traumatic brain injury and support the consideration of Phase I/II clinical trials.

Non-surgical management of spinal cord injury.

Spinal cord injury remains a devastating neurological condition with limited therapeutic opportunities. Since decompressive surgery and high-dose methylprednisolone have limited utility for most patients, spinal cord injury clearly represents a major medical challenge. Experimental evidence has suggested that secondary cellular injury processes may be a realistic target for therapeutic intervention with the goal of inhibiting the progression of detrimental changes that normally follows traumatic injury to the cord. Preventing or reducing this delayed cellular injury may alone improve neurological recovery or facilitate future regenerative approaches to the injured cord. This review summarises recent advances in the development of pharmacological agents targeting the acute phase of spinal cord injury as well as potential strategies to facilitate regeneration of the spinal cord.