Beach T, Yamada N, Makino S, Tooyama I. Infiltration of T lymphocytes and expression of icam-1 in the hippocampus of patients with hippocampal sclerosis

We and others have previously shown that reactive microglia express the major histocompatibility complex (MHC) class I and class II antigens in the hippocampus of patients suffering from epilepsy. Although the MHC glycoproteins serve as restriction elements for T lymphocytes, there is little information available regarding T lymphocytes in hippocampal sclerosis. In the present study, we investigated T lymphocyte infiltration in human hippocampi in four cases of epilepsy with hippocampal sclerosis, as well as in four control cases without neurological disease. No CD8- or CD4-positive T lymphocytes were seen in hippocampi from the control cases. In contrast, CD8- and CD4-positive T lymphocytes had infiltrated into the hippocampi of patients with hippocampal sclerosis. In addition, expression of intercellular adhesion molecule-1 was diffusely upregulated in the hippocampi with hippocampal sclerosis. These results indicate that T lymphocyte infiltration is involved in the pathology of hippocampal sclerosis.

Neuronal damage in rat brain and spinal cord after cardiac arrest and massive hemorrhagic shock*

OBJECTIVE

Severe global ischemia often results in severe damage to the central nervous system of survivors. Hind-limb paralysis is a common deficit caused by global ischemia. Until recently, most studies of global ischemia of the central nervous system have examined either the brain or spinal cord, but not both. Spinal cord damage specifically after global ischemia has not been studied in detail. Because the exact nature of the neuronal damage to the spinal cord and the differences in neuronal damage between the brain and spinal cord after global ischemia are poorly understood, we developed a new global ischemia model in the rat and specifically studied spinal cord damage after global ischemia. Further, we compared the different forms of neuronal damage between the brain and spinal cord after global ischemia.

DESIGN

Randomized, controlled study using three different global ischemia models in the rat.

SETTING

University research laboratory.

SUBJECTS

Male, adult Sprague-Dawley rats (300 g).

INTERVENTIONS

Animals were divided into three experimental groups, group A (n = 6, survived for 7 days), 12 mins of hemorrhagic shock; group B (n = 6, survived for 7 days), 5 mins of cardiac arrest; or group C (n = 6, each for 6 hrs, 12 hrs, 1 day, 3 days, and 7 days), 7 mins of hemorrhagic shock and 5 mins of cardiac arrest. Motor deficit of the hind limbs was studied 6 hrs to 7 days after resuscitation. Also, nonoperated animals (n = 6) were used as the control. Histologic analysis (hematoxylin and eosin, Fluoro-Jade B, terminal deoxynucleotidyl transferase- mediated dUTP end-labeling [TUNEL], Klüver-Barrera) and ultrastructural analysis using electron microscopy were performed on samples from the CA1 region of the hippocampus and lumbar spinal cord. Demyelination of the white matter of the lumbar spinal cord was analyzed semiquantitatively using Scion Image software.

MAIN RESULTS

No paraplegic animals were observed in either group A or B. All group C animals showed severe hind-limb paralysis. Severe neuronal damage was found in the CA1 region of the hippocampus in all groups, and the state of delayed neuronal cell death was similar among the three groups. Neuronal damage in the lumbar spinal cord was detected only in group C animals, mainly in the dorsal horn and intermediate gray matter. Demyelination was prominent in the ventral and ventrolateral white matter in group C. A significant difference was observed between control and group C rats with Scion Image software. Ultrastructural analysis revealed extensive necrotic cell death in the intermediate gray matter in the lumbar spinal cord in group C rats.

CONCLUSION

The combination in the global ischemia model (i.e., hemorrhagic shock followed by cardiac arrest) caused severe neuronal damage in the central nervous system. Thereby, hind-limb paralysis after global ischemia might result from spinal cord damage. These results suggest that therapeutic strategies for preventing spinal cord injury are necessary when treating patients with severe global ischemia.

Delayed expressed TNFR1 co-localize with ICAM-1 in astrocyte in mice brain after transient focal ischemia

Intercellular adhesion molecule-1 (ICAM-1) is expressed after brain ischemia and is participated in the induction of neuronal cell death. Recently, we have reported that ICAM-1 is localized in astrocytes in the chronic phase of ischemia. However, the regulation of astroglial ICAM-1 after brain ischemia is not elucidated in detail. Therefore, we examined the gene and protein expression of TNFR1 after transient middle cerebral artery occlusion (tMCAO) by using real time-PCR and immunohistochemistry. Moreover, we determined the relationship of TNFR1 and ICAM-1 in the astrocyte in chronic phase of ischemia. Increased expression of TNFR1 mRNA in the ipsilateral cortex was noted slightly during ischemia and was significantly increased at 12 h after reperfusion. Few TNFR1-like imuunoreactivity (TNFR1-LI) was observed in the cortex of normal animals. However, TNFR1-LI was increased at 1 h during ischemia, then it was decreased at 3-6 h, and was increased again at 12-24 h after reperfusion in the core of ischemic area. TNFR1-LI was demonstrated in both neurons and astrocytes but not in oligodendrocytes and microglia/macrophages at 24 h after reperfusion. At 96 h after tMCAO, TNFR1-LI was increased in the perifocal region and it appeared to be displayed the astrocyte-like cells. By use of double immunostaining method, we found that the ICAM-1-LI was overlapped with GFAP-LI. Our data indicates that the expression of TNFR1 is up-regulated in accordance with ischemic insult and delayed expressed TNFR1-LI co-localized with ICAM-1-LI in astrocytes after tMCAO. These results suggest that astroglial ICAM-1 is regulated by TNF-alpha dependent pathway.