Hadi Kazemi

Neuronal death by repetitive cortical spreading depression in juvenile rat brain

Spreading depression (SD) is an intrinsic bioelectrical property of the human central nervous system, which plays a key role in neurological disorders. In the present study, we investigated whether experimentally induced repetitive SD caused neuronal death in cortical and subcortical regions of the juvenile rat brain. The animals were anesthetized and the electrodes as well as a cannula were implanted over the brain. Repetitive cortical SD events were induced by KCl injection. The brains were removed after 4 weeks. Repetitive SD enhanced the production of dark neurons, reduced the mean volume of normal neurons, increased the number of apoptotic neurons, and enhanced expression of the NR(2B) subunit of NMDA receptors as well as the GluR1 subunit of AMPA receptors in various regions of the juvenile rat brain. In addition, induction of repetitive SD enhanced long-term potentiation in CA1 hippocampal area. We observed a correlation between cell injury/neuronal death induced by repetitive SD and changes in glutamate receptor expression. The data indicate that repetitive cortical SD in juvenile rats causes neuronal damage in both cortical and subcortical areas of the brain. This may play an important role in the pathophysiology of SD-related neurological disorders, especially in children.

Anticonvulsant and neuroprotective effects of Pimpinella anisum in rat brain.

BackgroundEssential oil of Pimpinella anisum L. Apiaceae (anise oil) has been widely used in traditional Persian medicine to treat a variety of diseases, including some neurological disorders. This study was aimed to test the possible anti-seizure and anti-hypoxia effects of anise oil.MethodsThe effects of different concentrations of anise oil were tested on seizure attacks induced by pentylenetetrazol (PTZ) injection and neuronal hypoxia induced by oxygen withdrawal as well as on production of dark neurons and induction of long-term potentiation (LTP) in in vivo and in vitro experimental models of rat brain.ResultsAnise oil significantly prolonged the latency of seizure attacks and reduced the amplitude and duration of epileptiform burst discharges induced by injection of intraperitoneal PTZ. In addition, anise oil significantly inhibited production of dark neurons in different regions of the brain in epileptic rats. Anise oil also significantly enhanced the duration of the appearance of anoxic terminal negativity induced by oxygen withdrawal and inhibited induction of LTP in hippocampal slices.ConclusionsOur data indicate the anticonvulsant and neuroprotective effects of anise oil, likely via inhibition of synaptic plasticity. Further evaluation of anise oil to use in the treatment of neurological disorders is suggested.

Sequential changes in neuronal activity in single neocortical neurons after spreading depression

Background: Cortical spreading depression (CSD) has an important role in migraine with aura. Prolonged neuronal depression is followed by a late excitatory synaptic plasticity after CSD. Method: Intra- and extracellular recordings were performed to investigate the effect of CSD on intracellular properties of mouse neocortical tissues in the late excitatory period. Results: During CSD, changes in the membrane potentials usually began with a relatively short hyperpolarization followed by an abrupt depolarization. These changes occurred roughly at the same time point after CSD as the beginning of the negative extracellular deflection. Forty-five minutes after CSD, neurons showed significantly smaller amplitude of afterhyperpolarization and a reduced input resistance. Depolarization and hyperpolarization of the cells by constant intracellular current injections in this period significantly changed the frequency of the action potentials. Conclusion: These data indicate higher excitability of the neocortical neurons after CSD, which can be assumed to contribute to hyperexcitability of neocortical tissues in patients suffering from migraine.

In vitro differentiation of bone marrow stromal cells into oligodendrocyte-like cells using triiodothyronine as inducer.

ABSTRACT An in vitro technique was devised to induced autologous adult stem cells into oligodendrocyte-like cells. In this study, a protocol was developed for the induction of bone marrow stromal cells (BMSCs) into oligodendrocyte-like cells. BMSCs were incubated in one of these three pre-inducers: dimethyl sulfoxide (DMSO), β-mercaptoethanol (βME) or biotylated hydroxyanisol (BHA), each followed by retinoic acid (RA) treatment. The percentage of viable cells in BHA-RA preinduced cells was significantly lower than the others. The results showed that the preinduced cells were immunoreactive for nestin and NF-68; among the mentioned protocols, the immunoreactivity yielded by following the DMSO-RA protocol was significantly higher than the others. Moreover, no significant immunoreactivity was observed for preinduced cells to O4, O1, MBP (myelin basic protein), S100, and GFAP (glial fibrillary acidic protein). The cells were immunoreactive to oligo-2. Two phases of induction were done: the first was a combination of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) and heregulin (HRG), followed by either triiodothyronine (T3) or Forskolin (FSK) as the second phase. The conclusion is that the trans-differentiation of BMSCs by DMSO followed by RA (preinduction stage) then bFGF-PDGF-HRG followed by T3 (10 ng/ml) (induction stage) can be a potential source for oligodendrocyte-like cells preparation.

Induction of bone marrow stromal cells into GABAergic neuronal phenotype using creatine as inducer

PURPOSE Deficits involving GABAergic neurons have been reported in aging, central nervous trauma and neurodegenerative disorders; bone marrow stromal cells (BMSCs) have been proposed as a feasible source of donor cells in replacement cell therapy. In this study, the effects of creatine on transdifferentiating BMSCs into GABAergic-like neurons were evaluated in vitro. METHODS The BMSCs were isolated from adult rats, preinduced by β-mercaptoethanol (BME) and retinoic acid (RA), and then induced by creatine into GABAergic-like neurons. The cells were characterized using different differentiation markers. The functionality of the differentiated cells was evaluated using FM1-43. RESULTS The isolated cells expressed Oct-4 and were immunoreactive to fibronectin and CD44. The highest percentages of cells immunoreactive to nestin and neurofilament-68 were found at the second day of preinduction. At the induction stage, there were increases in the number of cells immunoreactive to neurofilament-200, MAP-2, synapsin I, synaptophysin, and NeuN. The percentages of the immunoreactive cells to GABAergic neuron markers increased. The optimal induction dose was 5 mM. The dose of 10 mM showed a decline in the expression of most of these markers. The functionality test indicated that the synaptic vesicles were released upon stimulation. CONCLUSION Creatine can induce the differentiation of BMSCs to the GABAergic neuronal phenotype within one week.

Intractable epilepsy and craniocerebral trauma: Analysis of 163 patients with blunt and penetrating head injuries sustained in war

Post-traumatic epileptic seizure is a common complication of brain trauma including military injuries. We present clinical characteristics and correlates of post-traumatic epilepsy in 163 head-injured veterans suffering from intractable epilepsy due to blunt or penetrating head injuries sustained during the Iraq-Iran war. The medical records of 163 war veterans who were admitted by the Epilepsy Department of the Shefa Neuroscience Center between 2005 and 2009 were retrospectively reviewed. The mean follow-up period after developing epilepsy was 17.2 years. The time interval between the trauma and the first seizure was shorter and the seizure frequency was higher in epileptic patients suffering from penetrating head trauma. There was no difference in seizure type between epileptic patients traumatised by blunt or penetrating injury. Patients with seizure frequency of more than 30 per month mostly had simple partial seizure. Frontal and parietal semiologies were observed more frequently in patients with penetrating trauma, whereas patients with blunt trauma showed a higher temporal semiology. The most common brain lesion observed by CT scan was encephalomalacia followed by porencephaly and focal atrophy. There was no association between intracerebral retained fragments and different characteristic features of epilepsy. Patients with military brain injury carry a high risk of intractable post-traumatic epilepsy decades after their injury, and thus require a long-term medical follow-up.

Gastrointestinal adverse effects of antiepileptic drugs in intractable epileptic patients.

Gastrointestinal (GI) discomforts are among the most common side effects of antiepileptic drugs (AEDs) that might lead to discontinuation or irregular consumption of the drugs. This study was conducted to evaluate the frequency of GI side effects of different AEDs in intractable epileptic patients treated with single or multiple drugs. GI discomfort of 100 epileptic patients (aged 35-76 years) treated with one or multiple AEDs was assessed. Seventy six patients (76%) were treated with two or more AEDs, and 24 (24%) were on monotherapy. The most common prescribed drug for monotherapy was carbamazepine and the most frequent combination was phenytoin and carbamazepine. Patients were suffering from different GI side effects including heartburn (34.6%), nausea (33.7%), constipation (26%), vomiting (22.1%), diarrhea (21.2%) and dysphagia (19.2%). Nausea and vomiting were significantly higher in patients receiving monotherapy with carbamazepine and valproic acid, respectively. When phenytoin, gabapentine, or valproic acid was added to the other AEDs, the risk of the occurrence of diarrhea, dysphagia, or heartburn was significantly increased, respectively. Addition of gabapentine to the other AEDs in multiple drug therapy was accompanied with the highest frequency of GI complications. This study indicated that GI side effects, which can affect drug absorption and utilization, were common in intractable epileptic patients with long-term AEDs treatment. This may influence the efficacy of the therapy with AEDs and enhance the probability of further attacks.

Long term impact of sulfur mustard exposure on peripheral blood mononuclear subpopulations--Sardasht-Iran Cohort Study (SICS).

The most important long-term morbidity problem of sulfur mustard (SM) toxicity is pulmonary complications but the pathogenesis of these complications is not clearly understood. This study evaluates the peripheral blood mononuclear sub-sets and their correlation with pulmonary function in SM exposed civilian cases 20 years post-exposure as gathered in the context of the Sardasht-Iran Cohort Study (SICS). Samples were randomly selected from two groups, SM-exposed (n=372) and control (n=128), with the same ethnicity, culture, and demography. Three color flow cytometry was applied for peripheral blood mononuclear sub-population determination. Results indicated a significant decrease in CD45+/CD3+, CD45+/CD3+/CD4+, and an increase in CD3+/CD16+56+ percentages. It was also found that absolute count of NK cells was highly increased in peripheral blood of exposed cases. There was a significant increase in NK cell count of SM exposed group with pulmonary problems as compared to the same group without pulmonary problems (p-value<0.04) based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD). The findings showed a significant negative correlation between absolute numbers of T lymphocyte and FVC % and positive correlation with FEV1/FVC%. The results also demonstrated that absolute numbers of monocytes had a negative correlation with FVC %. We propose that NK and T cells are probably involved in the pathogenesis or immune reactions to the delayed pulmonary complications induced by SM. This hypothesis should be tested in a more severe pulmonary complicated group.

Diminution of the NMDA receptor NR2B subunit in cortical and subcortical areas of WAG/Rij rats

Modulation of glutamatergic NMDA receptors affects the synchronization of spike discharges in in WAG/Rij rats, a valid genetic animal model of absence epilepsy. In this study, we describe the alteration of NR2B subunit of NMDA receptors expression in WAG/Rij rats in different somatosensory cortical layers and in hippocampal CA1 area. Experimental groups were divided into four groups of six rats of both WAG/Rij and Wistar strains with 2 and 6 months of age. The distribution of NR2B receptors was assessed by immunohistochemical staining in WAG/Rij and compared with age‐matched Wistar rats. The expression of NR2B subunit was significantly decreased in different somatosensory cortical layers in 2‐ and 6‐month‐old WAG/Rij rats. In addition, the distribution of NR2B in hippocampal CA1 area was lower in 6‐month‐old WAG/Rij compared with age‐matched Wistar rats. The reduction of NR2B receptors in different brain areas points to disturbance of glutamate receptors expression in cortical and subcortical areas in WAG/Rij rats. An altered subunit assembly of NMDA receptors may underlie cortical hyperexcitability in absence epilepsy. Synapse 67:839–846, 2013.

Intraspinal delivery of bone marrow stromal cell-derived neural stem cells in patients with amyotrophic lateral sclerosis: A safety and feasibility study

BACKGROUND Stem cells have been used in several studies with different methodologies to treat patients with ALS. METHODS In this safety and feasibility study, 11 patients with definite or probable ALS according to El Escorial criteria were selected. 3 patients were excluded due to inadequate bone marrow or safety measures after acquisition of bone marrow. Bone marrow stromal cell-derived neural stem cells were injected in C7-T1 spinal cord under general anesthesia. Patients were followed for 12months after injection with manual muscle testing, ALSFRS-R, quality of life changes, pulmonary function test and electromyography. RESULTS None of the patients had perioperative mortality or major morbidity. One patient had temporary deterioration in lower extremities after injection which improved after a few weeks. In the 12months post-injection, only one patient died due to pulmonary embolism. From the remaining 7 patients, all had a stable course after 4months and 5 were stable for the first 8months post-injection and deteriorated afterwards. DISCUSSION In this study, intraspinal injection of bone marrow derived neural stem cells appears to be safe. Patients experienced a temporary stabilization for the first few months post-injection and then gradually deteriorated.