Free fatty acids, lipid peroxidation, and lysosomal enzymes in experimental focal cerebral ischemia in primates: Loss of lysosomal latency by lipid peroxidation

Abstract

Experimental focal cerebral ischemia was produced in monkeys (Macaca radiata) by occlusion of the right middle cerebral artery (MCA). The release of the lysosomal glycosidases, beta-D-hexosaminidase, alpha-L-fucosidase and alpha-D-mannosidase into the soluble fraction in the right basal ganglia of the experimental animals was measured at different periods from 30 min to 12 hr after occlusion and compared with the corresponding sham operated control animals. There was a significant increase in the released lysosomal enzymes in the MCA occluded animals at all periods and particularly at 4 hr after occlusion. The CSF from the experimental animals also showed elevated levels of hexosaminidase and fucosidase. The free fatty acids (FFA) measured in the basal ganglia at 30 min and 2 hr after occlusion showed a 100 fold increase in the experimental animals. The predominant fatty acid released was linoleic acid (18:2) followed by arachidonic acid (20:4). Lipid peroxidation in the basal ganglia measured by the thiobarbituric acid (TBA) reaction in the presence or absence of ascorbic acid also showed a significant increase in the experimental animals at all periods with a maximum at 30 min to 2 hr after occlusion. In order to assess whether lipid peroxidation causes damage to the lysosomes and release of the enzymes, a lysosome enriched P2 fraction from the normal monkey basal ganglia was prepared and the effect of peroxidation studied. Maximum peroxidation in the P2 fraction was observed in the presence of arachidonic acid, ascorbic acid and Fe2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Apoptotic and Necrotic Death Mechanisms Are Concomitantly Activated in the Same Cell After Cerebral Ischemia

“…Extralysosomal cathepsin-B immunolabeling is in accord with a biochemical study reporting significant increases in released lysosomal enzymes in monkey brain 4 hours after MCA occlusion. 32 Like loss of plasma membrane integrity, lysosomal membrane disintegration also coexisted with caspase-3 activation in the same cell at early hours of ischemia. Cathepsin-B spilled into cytoplasm may contribute to development of necrotic features by digesting structural and functional proteins, whereas it reinforces apoptotic mechanisms such as Bid cleavage and caspase activation 18 that are also activated by several other factors in ischemic cells.…”

Inhibition of ischaemic hippocampal neuronal death in primates with cathepsin B inhibitor CA‐074: a novel strategy for neuroprotection based on ‘calpain–cathepsin hypothesis’

“…Recently, there are many studies on intracellular proteases in order to clarify the mechanism of neuronal cell death and to plan the neuroprotective strategies (Nagarajan et al . 1988; Lee et al .…”

“…Lysosomal rupture as a mechanism leading to cell death Recently, there are many studies on intracellular proteases in order to clarify the mechanism of neuronal cell death and to plan the neuroprotective strategies (Nagarajan et al, 1988;Lee et al, 1991;Nakanishi et al, 1993;Nixon & Cataldo, 1993;Saido et al, 1993;Bartus et al, 1994;Hong et al, 1994;Nitatori et al, 1995;Yokota et al, 1995). Although the membrane stability of neuronal lysosomes is known to be reduced as a result of ageing (Nakamura et al, 1989) or Alzheimer's disease (Bowen et al, 1973), the possibility of lysosomal rupture as a mechanism leading to neuronal death has not been reported in any detail except for our previous studies using a monkey model with whole brain ischaemia Kohda et al, 1996).…”

Immunohistochemical localization of lysosomal cysteine protease cathepsins B and L in monkey hippocampal neurons after transient ischemia

“…These enzymes are accepted to be indispensable for the physiological turnover of cellular proteins in neurons 27 . Recently, there have been many reports concerning roles of intracellular protease in both clarifying the mechanism of neuronal cell death and planning the neuroprotective strategies 18,19,27–34 . Cathepsins B and L are two major lysosomal proteases of neurons and are crucial for the intracellular catabolism of numerous proteins.…”