Intracisternal administration of tanshinone IIA-loaded nanoparticles leads to reduced tissue injury and functional deficits in a porcine model of ischemic stroke

Background

The absolute number of new stroke patients is annually increasing and there still remains only a few Food and Drug Administration (FDA) approved treatments with significant limitations available to patients. Tanshinone IIA (Tan IIA) is a promising potential therapeutic for ischemic stroke that has shown success in pre-clinical rodent studies but lead to inconsistent efficacy results in human patients. The physical properties of Tan-IIA, including short half-life and low solubility, suggests that Poly (lactic-co-glycolic acid) (PLGA) nanoparticle-assisted delivery may lead to improve bioavailability and therapeutic efficacy. The objective of this study was to develop Tan IIA-loaded nanoparticles (Tan IIA-NPs) and to evaluate their therapeutic effects on cerebral pathological changes and consequent motor function deficits in a pig ischemic stroke model.

Results

Tan IIA-NP treated neural stem cells showed a reduction in SOD activity in in vitro assays demonstrating antioxidative effects. Ischemic stroke pigs treated with Tan IIA-NPs showed reduced hemispheric swelling when compared to vehicle only treated pigs (7.85 ± 1.41 vs. 16.83 ± 0.62%), consequent midline shift (MLS) (1.72 ± 0.07 vs. 2.91 ± 0.36 mm), and ischemic lesion volumes (9.54 ± 5.06 vs. 12.01 ± 0.17 cm³) when compared to vehicle-only treated pigs. Treatment also lead to lower reductions in diffusivity (-37.30 ± 3.67 vs. -46.33 ± 0.73%) and white matter integrity (-19.66 ± 5.58 vs. -30.11 ± 1.19%) as well as reduced hemorrhage (0.85 ± 0.15 vs 2.91 ± 0.84 cm³) 24 h post-ischemic stroke. In addition, Tan IIA-NPs led to a reduced percentage of circulating band neutrophils at 12 (7.75 ± 1.93 vs. 14.00 ± 1.73%) and 24 (4.25 ± 0.48 vs 5.75 ± 0.85%) hours post-stroke suggesting a mitigated inflammatory response. Moreover, spatiotemporal gait deficits including cadence, cycle time, step time, swing percent of cycle, stride length, and changes in relative mean pressure were less severe post-stroke in Tan IIA-NP treated pigs relative to control pigs.

Conclusion

The findings of this proof of concept study strongly suggest that administration of Tan IIA-NPs in the acute phase post-stroke mitigates neural injury likely through limiting free radical formation, thus leading to less severe gait deficits in a translational pig ischemic stroke model. With stroke as one of the leading causes of functional disability in the United States, and gait deficits being a major component, these promising results suggest that acute Tan IIA-NP administration may improve functional outcomes and the quality of life of many future stroke patients.

Teratoma-negative anti-NMDA receptor encephalitis presenting with a single generalized tonic-clonic seizure

Herein, we describe a case report of anti-NMDA receptor encephalitis characterized by a single generalized tonic–clonic seizure and predominantly psychiatric symptoms, persisting long after EEG abnormalities had resolved. We discuss common presentations of anti-NMDA receptor encephalitis and advocate for the inclusion of this disease entity in the differential diagnosis of patients presenting with one generalized tonic–clonic seizure and prominent psychiatric symptoms.

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Teratoma-negative anti-NMDA receptor encephalitis presented with a single GTC seizure and prominent psychiatric symptoms.

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We emphasize the importance of early treatment with immunotherapy in autoimmune epilepsy.

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The literature on acute anti-NMDA receptor encephalitis presenting with one GTC seizure is reviewed.

Lysine-restricted diet and mild cerebral serotonin deficiency in a patient with pyridoxine-dependent epilepsy caused by ALDH7A1 genetic defect

Pyridoxine dependent epilepsy (PDE) is caused by mutations in the ALDH7A1 gene (PDE-ALDH7A1) encoding α-aminoadipic-semialdehyde-dehydrogenase enzyme in the lysine catabolic pathway resulting in an accumulation of α-aminoadipic-acid-semialdehyde (α-AASA).

We present the one-year treatment outcome of a patient on a lysine-restricted diet. Serial cerebral-spinal-fluid (CSF) α-AASA and CSF pipecolic-acid levels showed decreased levels but did not normalize. He had a normal neurodevelopmental outcome on a lysine-restricted diet. Despite normal CSF and plasma tryptophan levels and normal tryptophan intake, he developed mild CSF serotonin deficiency at one year of therapy.

Stricter lysine restriction would be necessary to normalize CSF α-AASA levels, but might increase the risks associated with the diet. Patients are at risk of cerebral serotonin deficiency and should be monitored by CSF neurotransmitter measurements.