Unfavorable effect of levetiracetam on cultured hippocampal neurons after hyperthermic injury

BACKGROUND

The aim of this study was to examine the viability of neurons and the putative neuroprotective effects of second-generation antiepileptic drug, levetiracetam (LEV), on cultured hippocampal neurons injured by hyperthermia.

METHODS

Primary cultures of rat's hippocampal neurons at 7 day in vitro (DIV) were incubated in the presence or absence of LEV in varied concentrations under hyperthermic conditions. Cultures were heated in a temperature of 40 °C for 24 h or in a temperature of 41 °C for 6 h. Flow cytometry with Annexin V/PI staining as well as fluorescent microscopy assay were used for counting and establishing neurons as viable, necrotic or apoptotic. Additionally, the release of lactate dehydrogenase (LDH) to the culture medium, as a marker of cell death, was evaluated. Assessment was performed after 9DIV and 10 DIV.

RESULTS

Incubation of hippocampal cultures in hyperthermic conditions resulted in statistically significant increase in the number of injured neurons when compared with non-heated control cultures. Intensity of neuronal destruction was dependent on temperature-value. When incubation temperature 40 °C was used, over 80% of the population of neurons remained viable after 10 DIV. Under higher temperature 41 °C, only less than 60% of neurons were viable after 10 DIV. Both apoptotic and necrotic pathways of neuronal death induced by hyperthermia were confirmed by Annexin V/PI staining.

CONCLUSIONS

LEV showed no neuroprotective effects in the current model of hyperthermia in vitro. Moreover, drug, especially when used in higher concentrations, exerted unfavorable intensification of aponecrosis of cultured hippocampal neurons.

Fibroblast-Like Synovial Cells in Rheumatoid Arthritis--the Impact of Infliximab on Hexosaminidase Activity

BACKGROUND

The effect of multiple infusions of infliximab (INF), a chimeric anti-tumor necrosis factor alpha antibody, on the concentration of hexosaminidase (HEX) activity in a synovial cell culture derived from human synovial inflamed fluid obtained from patients suffering from rheumatoid arthritis (RA) has been evaluated.

OBJECTIVES

The aim of this study was to prove INF efficacy in RA.

MATERIAL AND METHODS

Inflamed synovial fluid was taken from RA patients (a study group) and patients who had undergone knee trauma within 7 days (a control group). The following solutions of infliximab were used: 40, 60 and 140 µg/mL. Determination of the concentration of HEX activity in cell cultures was performed after 24, 48, 72 and 96 h of infliximab administration. To identify synoviocytes in cell culture immunohistochemical staining with vimentin and pancytokeratin was performed.

RESULTS

A predominance of fibroblast-like synovial cells has been observed in the study group. In the control group the concentration of HEX activity without adding infliximab to the cell culture was 283.00 nkat/mL. After 96 h of incubation with infliximab, the concentrations of HEX activity in cultured synoviocytes according to infliximab doses of 40, 60 and 140 µg/mL were respectively: 280.00, 271.50 and 293.50 nkat/mL. In the study group, the concentration of HEX activity without adding infliximab to the cell culture was 542.27 nkat/mL. The final concentrations of HEX activity of cultured fibroblast-like synovial cells measured after 96 h of incubation with infliximab were: 471.72, 498.27 and 556.72 nkat/mL, according to infliximab doses of 40, 60 and 140 µg/mL. In all groups (besides the infliximab concentration of 140 µg/mL after 96 h of incubation), the level of concentration of HEX activity was significantly higher in the study group compared to the control group, irrespective of infliximab concentration and time of infliximab incubation.

CONCLUSIONS

Infliximab changes the concentration of HEX activity depending on the drug dose and time of administration.