Increased Metallothionein I/II Expression in Patients with Temporal Lobe Epilepsy

Abstract

In the central nervous system, zinc is released along with glutamate during neurotransmission and, in excess, can promote neuronal death. Experimental studies have shown that metallothioneins I/II (MT-I/II), which chelate free zinc, can affect seizures and reduce neuronal death after status epilepticus. Our aim was to evaluate the expression of MT-I/II in the hippocampus of patients with temporal lobe epilepsy (TLE). Hippocampi from patients with pharmacoresistant mesial temporal lobe epilepsy (MTLE) and patients with TLE associated with tumor or dysplasia (TLE-TD) were evaluated for expression of MT-I/II, for the vesicular zinc levels, and for neuronal, astroglial, and microglial populations. Compared to control cases, MTLE group displayed widespread increase in MT-I/II expression, astrogliosis, microgliosis and reduced neuronal population. In TLE-TD, the same changes were observed, except that were mainly confined to fascia dentata. Increased vesicular zinc was observed only in the inner molecular layer of MTLE patients, when compared to control cases. Correlation and linear regression analyses indicated an association between increased MT-I/II and increased astrogliosis in TLE. MT-I/II levels did not correlate with any clinical variables, but MTLE patients with secondary generalized seizures (SGS) had less MT-I/II than MTLE patients without SGS. In conclusion, MT-I/II expression was increased in hippocampi from TLE patients and our data suggest that it is associated with astrogliosis and may be associated with different seizure spread patterns.

Microtubule-Associated Proteins in Mesial Temporal Lobe Epilepsy with and without Psychiatric Comorbidities and Their Relation with Granular Cell Layer Dispersion

“…Also, we used as controls hippocampi from necropsy with longer delays before fixation than those for our surgical specimens. There is evidence that postmortem intervals up to 24 h do not interfere significantly with protein levels, cell morphology, and tissue integrity [42, 73, 74]. Furthermore, our controls showed no correlations between postmortem delays and MAPs expression.…”

“…In brief, all digitized images were analyzed with Image J software, following the same criteria: (I) the software identifies the gray value distribution of a subfield's digital image (total area for each subfield = 313.7  μ m × 235.3  μ m); (II) the immunoreactive area is selected (i.e., positive stained pixels), limited to a threshold range; and (III) the threshold range is presettled based on control group sections to exclude the low-intensity gray value of background staining from the analysis. A similar approach was used by our group elsewhere [42]. Results for granular layer included granular cell layer per se and proximal molecular layer.…”

Mesial temporal lobe epilepsy with psychiatric comorbidities: a place for differential neuroinflammatory interplay

“…Antibodies specificity was verified, and immunohistochemistry was performed as described in Peixoto-Santos et al [4]. Briefly, paraffin-embedded MTLE and control hippocampi were processed together for each antibody, with overnight incubation at room temperature, and developed simultaneously in 0.05% 3,3′-diaminobenzidine tetrahydrochloride (Pierce, Rockford, USA) and 0.01% hydrogen peroxide (Merck, Darmstadt, Germany).…”

“…Immunoreactivity were estimated in 8-μm Neu-N stained slices at × 200 magnification as previously described and well established in the literature for surgical hippocampal fragments [1,3,4,29,30]. …”

Selective post-training time window for memory consolidation interference of cannabidiol into the prefrontal cortex: Reduced dopaminergic modulation and immediate gene expression in limbic circuits

“…Immunohistochemistry was performed in 8-mm-thick coronal brain sections, following published protocol (Peixoto-Santos et al, 2012). In order to avoid cannula lesion and secondary tissue damage, we only used sections collected posterior to the cannula track with no signs of scars and gliosis.…”