Neuroprotective Effects of a Variety of Pomegranate Juice Extracts (PJE) Against the Excitotoxin Quinolinic Acid in Human Primary Neurons

BACKGROUND

Quinolinic acid (QUIN) excitotoxicity is mediated by elevated intracellular Ca2+ levels, and nitric oxide (NO•) mediated oxidative stress leading to DNA damage, and cell death due to energy restriction.

METHODS

We evaluated the effect of a series of pomegranate juice extracts (PJE), Helow, Malasi, Qusum, and Hamedh, with antioxidant properties on QUIN induced excitotoxicity on primary cultures of human neurons.

RESULTS

We showed that Helow and Malasi can attenuate QUIN-induced excitotoxicity to a greater extent than Qusum and Hamedh from Oman. Similarly, both Helow and Malasi were able to attenuate QUIN-induced Ca2+ influx and nNOS activity to a greater extent compared to Qusum, and Hamedh. All extracts reduced the oxidative effects of increased NO• production, and hence preventing NAD+ depletion and cell death.

CONCLUSION

In addition to the well-known antioxidant properties of these natural phytochemicals, the inhibitory effect of some of these compounds on specific excitotoxic processes such as calcium influx provides additional evidence for the beneficial health effects of PJE in excitable tissue, particularly within the CNS.

fMRI Activation in Continuous and Spike-triggered EEG-fMRI Studies of Epileptic Spikes

PURPOSE

To evaluate functional magnetic resonance imaging (fMRI) with simultaneous EEG for finding metabolic sources of epileptic spikes. To find the localizing value of activated regions and factors influencing fMRI responses.

METHODS

Patients with focal epilepsy and frequent spikes were subjected to spike-triggered or continuous fMRI with simultaneous EEG. Results were analyzed in terms of fMRI activation, concordance with the location of EEG spiking and anatomic MRI abnormalities, and other EEG and clinical variables. In four patients, results also were compared with those of intracerebral EEG.

RESULTS

Forty-eight studies were performed on 38 patients. Seventeen studies were not analyzed, primarily because no spikes occurred during scanning. Activation was obtained in 39% of 31 studies, with an activation volume of 2.55 +/- 4.84 cc. Activated regions were concordant with EEG localization in almost all studies and confirmed by intracerebral EEG in four patients. Forty percent of patients without an MRI lesion showed activation; 37.5% of patients with a lesion had an activation; the activation was near or inside the lesion. Bursts of spikes were more likely to generate an fMRI response than were isolated spikes (76 vs. 11%; p < 0.05).

CONCLUSIONS

Combining EEG and fMRI in focal epilepsy yields regions of activation that are presumably the source of spiking activity. These regions are highly linked with epileptic foci and epileptogenic lesions in a significant number of patients. Activation also is found in patients with no visible MRI lesion. Intracerebral recordings largely confirm that these activation regions represent epileptogenic areas. It is still unclear why many patients show no activation.

Lymphocyte migration and multiple sclerosis: relation with disease course and therapy

Lymphocyte migration into the central nervous system is a central event in lesion formation in multiple sclerosis. By using a fibronectin-coated membrane Boyden chamber assay, we observed that migration rates of immediately ex vivo lymphocytes from patients with relapsing-remitting, with or without concurrent clinical relapse, or with secondary progressive disease, were increased compared with healthy donors. Migration rates of lymphocytes from relapsing-remitting multiple sclerosis patients receiving either glatiramer acetate (Copaxone 20 mg daily) or interferon-beta1b (Betaseron 8 MIU, three times per week) were significantly reduced compared with untreated relapsing-remitting patients. In vitro treatment with interferon-beta1b (1,000 U/ml), but not glatiramer acetate (20 microg/ml), significantly reduced lymphocyte-migration rates, suggesting that the effects of these two therapeutic agents on migration result from different mechanisms of actions. Interferon-beta1b acts, at least in part, by a direct effect on this cell property, whereas glatiramer acetate effects are indirect.