Biochemical markers in vascular cognitive impairment associated with subcortical small vessel disease - A consensus report.

BACKGROUND: Vascular cognitive impairment (VCI) is a heterogeneous entity with multiple aetiologies, all linked to underlying vascular disease. Among these, VCI related to subcortical small vessel disease (SSVD) is emerging as a major homogeneous subtype. Its progressive course raises the need for biomarker identification and/or development for adequate therapeutic interventions to be tested. In order to shed light in the current status on biochemical markers for VCI-SSVD, experts in field reviewed the recent evidence and literature data. METHOD: The group conducted a comprehensive search on Medline, PubMed and Embase databases for studies published until 15.01.2017. The proposal on current status of biochemical markers in VCI-SSVD was reviewed by all co-authors and the draft was repeatedly circulated and discussed before it was finalized. RESULTS: This review identifies a large number of biochemical markers derived from CSF and blood. There is a considerable overlap of VCI-SSVD clinical symptoms with those of Alzheimer's disease (AD). Although most of the published studies are small and their findings remain to be replicated in larger cohorts, several biomarkers have shown promise in separating VCI-SSVD from AD. These promising biomarkers are closely linked to underlying SSVD pathophysiology, namely disruption of blood-CSF and blood-brain barriers (BCB-BBB) and breakdown of white matter myelinated fibres and extracellular matrix, as well as blood and brain inflammation. The leading biomarker candidates are: elevated CSF/blood albumin ratio, which reflects BCB/BBB disruption; altered CSF matrix metalloproteinases, reflecting extracellular matrix breakdown; CSF neurofilment as a marker of axonal damage, and possibly blood inflammatory cytokines and adhesion molecules. The suggested SSVD biomarker deviations contrasts the characteristic CSF profile in AD, i.e. depletion of amyloid beta peptide and increased phosphorylated and total tau. CONCLUSIONS: Combining SSVD and AD biomarkers may provide a powerful tool to identify with greater precision appropriate patients for clinical trials of more homogeneous dementia populations. Thereby, biomarkers might promote therapeutic progress not only in VCI-SSVD, but also in AD.

Investigation of sex-specific effects of apolipoprotein E on severity of EAE and MS.

BACKGROUND: Despite pleiotropic immunomodulatory effects of apolipoprotein E (apoE) in vitro, its effects on the clinical course of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS) are still controversial. As sex hormones modify immunomodulatory apoE functions, they may explain contentious findings. This study aimed to investigate sex-specific effects of apoE on disease course of EAE and MS. METHODS: MOG(35-55) induced EAE in female and male apoE-deficient mice was assessed clinically and histopathologically. apoE expression was investigated by qPCR. The association of the MS severity score (MSSS) and APOE rs429358 and rs7412 was assessed across 3237 MS patients using linear regression analyses. RESULTS: EAE disease course was slightly attenuated in male apoE-deficient (apoE (-/-) ) mice compared to wildtype mice (cumulative median score: apoE (-/-) = 2 [IQR 0.0-4.5]; wildtype = 4 [IQR 1.0-5.0]; n = 10 each group, p = 0.0002). In contrast, EAE was more severe in female apoE (-/-) mice compared to wildtype mice (cumulative median score: apoE (-/-) = 3 [IQR 2.0-4.5]; wildtype = 3 [IQR 0.0-4.0]; n = 10, p = 0.003). In wildtype animals, apoE expression during the chronic EAE phase was increased in both females and males (in comparison to naïve animals; p < 0.001). However, in MS, we did not observe a significant association between MSSS and rs429358 or rs7412, neither in the overall analyses nor upon stratification for sex. CONCLUSIONS: apoE exerts moderate sex-specific effects on EAE severity. However, the results in the apoE knock-out model are not comparable to effects of polymorphic variants in the human APOE gene, thus pinpointing the challenge of translating findings from the EAE model to the human disease.

Supporting dementia patients and their caregivers in daily life challenges: review of physical, cognitive and psychosocial intervention studies.

BACKGROUND AND PURPOSE: Dementia is associated with multiple daily life challenges that have a major impact for health outcome, affecting both the patients and their caregivers. In this review, the efficacy of physical, cognitive and psychosocial interventions in the treatment of dementia patients is evaluated, and how caregiver education and support may contribute to patient care is analysed. RESULTS AND CONCLUSIONS: Due to the complex nature of cognitive and psychosocial interventions, their efficacy depends strongly on local settings. Thus, active components of these interventions are not always obvious, even in controlled randomized trials. Successful patient management includes (i) the safekeeping of basic support, (ii) the provision of a stable external milieu that is adjusted to the patients' cognitive resources and (iii) the provision of multimodal therapeutic concepts that are closely adapted to the practical needs of the patients and caregivers.

Supporting dementia patients in hospital environments: health-related risks, needs and dedicated structures for patient care.

The diagnostics and treatment of dementia are progressively gaining importance for European neurologists. Our hospital structures are poorly prepared for patients suffering from dementia. As a consequence of cognitive and physical deficits, dementia patients have an increased risk for serious complications and poor outcomes in hospital environments. In this review, the specific needs of dementia patients are outlined, describing how geriatricians, neurologists and psychiatrists may contribute to better patient care, e.g. with consultation or liaison services, geriatric wards, dedicated dementia wards or memory clinics in interaction with nurses, occupational therapists, physiotherapists, speech therapists, psychologists and social workers. Due to their multifaceted needs, dementia patients can most successfully be supported in clinical environments that closely integrate specialized inpatient, outpatient and primary care offers.

B-type natriuretic peptide predicts stroke of presumable cardioembolic origin in addition to coronary artery calcification.

BACKGROUND AND PURPOSE: B-type natriuretric peptide (BNP) is a marker of cardiac dysfunction that is released from myocytes in response to ventricular wall stress. Previous studies suggested that BNP predicts stroke events in addition to classical risk factors. It was suggested that the BNP-associated risk results from coronary atherosclerosis or atrial fibrillation. METHODS: Three thousand six hundred and seventy five subjects from the population-based Heinz Nixdorf Recall study (45-75 years; 47.6% men) without previous stroke, coronary heart disease, myocardial infarcts, open cardiac valve surgery, pacemakers and defibrillators were followed up over 110.1 ± 23.1 months. Cox proportional hazards regressions were used to examine BNP as a stroke predictor in addition to vascular risk factors (age, gender, systolic blood pressure, low-density lipoprotein, high-density lipoprotein, diabetes, smoking), renal insufficiency, atrial fibrillation/known heart failure and coronary artery calcification. RESULTS: Eighty-nine incident strokes occurred (80 ischaemic, 9 hemorrhagic). Subjects suffering stroke had significantly higher BNP values at baseline than the remaining subjects [26.3 (Q1; Q3 = 12.9; 51.0) vs. 17.4 (9.4; 31.4); P < 0.001]. In a multivariable regression, log10 BNP was an independent stroke predictor [hazard ratio 1.96, 95% confidence interval (CI) 1.13-3.41; P = 0.017] in addition to age (1.24 per 5 years, CI 1.04-1.49; P = 0.016), systolic blood pressure (1.25 per 10 mmHg, CI 1.14-1.38; P < 0.001), smoking (2.05, CI 1.24-3.39; P = 0.005), atrial fibrillation/heart failure (2.25, CI 1.05-4.83; P = 0.037) and computed-tomography-based log10 (coronary artery calcification + 1) (1.47, CI 1.15-1.88; P = 0.002). Log10 BNP predicted stroke in men but not women, both in subjects ≤65 and >65 years. In subsequent analyses, BNP discriminated the incidence of cardioembolic stroke (P for trend = 0.001), but not stroke of macroangiopathic (P = 0.555), microangiopathic (P = 0.809) or unknown (P = 0.367) origin. CONCLUSIONS: BNP predicts presumable cardioembolic stroke independent of coronary calcification.

Extracellular Vesicles Derived from Neural Progenitor Cells--a Preclinical Evaluation for Stroke Treatment in Mice.

Stem cells such as mesenchymal stem cells (MSCs) enhance neurological recovery in preclinical stroke models by secreting extracellular vesicles (EVs). Since previous reports have focused on the application of MSC-EVs only, the role of the most suitable host cell for EV enrichment and preclinical stroke treatment remains elusive. The present study aimed to evaluate the therapeutic potential of EVs derived from neural progenitor cells (NPCs) following experimental stroke. Using the PEG technique, EVs were enriched and characterized by electron microscopy, proteomics, rt-PCR, nanosight tracking analysis, and Western blotting. Different dosages of NPC-EVs displaying a characteristic profile in size, shape, cargo protein, and non-coding RNA contents were incubated in the presence of cerebral organoids exposed to oxygen-glucose deprivation (OGD), significantly reducing cell injury when compared with control organoids. Systemic administration of NPC-EVs in male C57BL6 mice following experimental ischemia enhanced neurological recovery and neuroregeneration for as long as 3 months. Interestingly, the therapeutic impact of such NPC-EVs was found to be not inferior to MSC-EVs. Flow cytometric analyses of blood and brain samples 7 days post-stroke demonstrated increased blood concentrations of B and T lymphocytes after NPC-EV delivery, without affecting cerebral cell counts. Likewise, a biodistribution analysis after systemic delivery of NPC-EVs revealed the majority of NPC-EVs to be found in extracranial organs such as the liver and the lung. This proof-of-concept study supports the idea of EVs being a general concept of stem cell-induced neuroprotection under stroke conditions, where EVs contribute to reverting the peripheral post-stroke immunosuppression.

Central periodic breathing during sleep in 74 patients with acute ischemic stroke - neurogenic and cardiogenic factors.

OBJECTIVES: The aims of our study were 1) to better characterize central periodic breathing during sleep (CPBS) and its clinical relevance in acute stroke, 2) to better define the role of brain damage in its pathogenesis. METHODS: We included 74 consecutive patients admitted within 96 hours after stroke onset. Stroke severity at admission, stroke outcome at discharge and stroke topography were assessed. ECG and transesophageal echocardiography were performed. Nocturnal breathing was assessed with an ambulatory device the first night after admission. CPBS severity was represented as absolute time and percentage of recording time. RESULTS: Age was 63 +/- 13 (25-82), 49 (66 %) were male. Thirty (41 %) patients showed CPBS during >or= 10 % and 7 (9 %) during >or= 50 % of recording time. CPBS severity was associated with age (p = 0.017), stroke severity (p = 0.008), ECG abnormalities (p = 0.005) and lower left ventricular ejection fraction (p < 0.0001). CPBS severity was higher in patients with extensive hemispheric strokes (n = 6, p < 0.0001), and lower in patients with partial strokes involving the left insula (n = 5, p < 0.0001) and the mesencephalon (n = 5, p = 0.002). CONCLUSIONS: CPBS is frequent in acute ischemic stroke and is associated with older age, stroke severity/extension, and lower left ventricular function. The lower occurrence of CPBS in left insular and mesencephalic stroke suggests a major role of distinct brain areas in the modulation of respiratory phenomena accompanying acute stroke.

Post-ischemic delivery of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor rosuvastatin protects against focal cerebral ischemia in mice via inhibition of extracellular-regulated kinase-1/-2.

After recent clinical trials, statins have gained increasing significance in secondary stroke prevention. From experimental studies, it is well established that statins have beneficial action when delivered prophylactically prior to a stroke. Conversely, much less is known about the effects of statins on injury development when delivered after ischemia. We here examined the effects of a post-ischemic delivery of rosuvastatin (0.5, 5 or 20 mg/kg, administered i.p. immediately after reperfusion onset), a potent 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on brain injury and cell signaling after focal cerebral ischemia, induced by 90 min of intraluminal middle cerebral artery occlusion in mice. In animals receiving normal saline, 0.5 or 5 mg/kg rosuvastatin, middle cerebral artery occlusions resulted in reproducible brain infarcts at 24 h after reperfusion onset, which did not differ in size. However, rosuvastatin, administered at higher doses (20 mg/kg), reduced infarct volume at 24 and 48 h after ischemia (by 34+/-16% and 18+/-3%, respectively, P<0.05). Western blots revealed that rosuvastatin decreased phosphorylated extracellular-regulated kinase-1/-2 and reduced activated caspase-3 levels in ischemic brain areas, while endothelial NO synthase expression, p38 and Jun kinase phosphorylation were not influenced by the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. Rosuvastatin also significantly diminished expression levels of inducible NO synthase in the ischemic brain. Our results indicate that rosuvastatin may have utility not only as stroke prophylaxis but also as acute therapy inhibiting executive cell death pathways.

Cellular prion protein promotes post-ischemic neuronal survival, angioneurogenesis and enhances neural progenitor cell homing via proteasome inhibition.

Although cellular prion protein (PrP(c)) has been suggested to have physiological roles in neurogenesis and angiogenesis, the pathophysiological relevance of both processes remain unknown. To elucidate the role of PrP(c) in post-ischemic brain remodeling, we herein exposed PrP(c) wild type (WT), PrP(c) knockout (PrP-/-) and PrP(c) overexpressing (PrP+/+) mice to focal cerebral ischemia followed by up to 28 days reperfusion. Improved neurological recovery and sustained neuroprotection lasting over the observation period of 4 weeks were observed in ischemic PrP+/+ mice compared with WT mice. This observation was associated with increased neurogenesis and angiogenesis, whereas increased neurological deficits and brain injury were noted in ischemic PrP-/- mice. Proteasome activity and oxidative stress were increased in ischemic brain tissue of PrP-/- mice. Pharmacological proteasome inhibition reversed the exacerbation of brain injury induced by PrP-/-, indicating that proteasome inhibition mediates the neuroprotective effects of PrP(c). Notably, reduced proteasome activity and oxidative stress in ischemic brain tissue of PrP+/+ mice were associated with an increased abundance of hypoxia-inducible factor 1α and PACAP-38, which are known stimulants of neural progenitor cell (NPC) migration and trafficking. To elucidate effects of PrP(c) on intracerebral NPC homing, we intravenously infused GFP(+) NPCs in ischemic WT, PrP-/- and PrP+/+ mice, showing that brain accumulation of GFP(+) NPCs was greatly reduced in PrP-/- mice, but increased in PrP+/+ animals. Our results suggest that PrP(c) induces post-ischemic long-term neuroprotection, neurogenesis and angiogenesis in the ischemic brain by inhibiting proteasome activity.

Effects of recombinant tissue plasminogen activator after intraluminal thread occlusion in mice: role of hemodynamic alterations.

BACKGROUND AND PURPOSE: It has been suggested that recombinant tissue plasminogen activator (rtPA) may cause an aggravation of injury after transient focal ischemia via excitotoxic side effects. Such rtPA toxicity would be of major clinical significance since rtPA is increasingly used in stroke treatment. This study was conducted to evaluate the effects of dose, application time, and hemodynamic changes after intravenous rtPA treatment in focal ischemia. METHODS: Mice were subjected to a 90-minute episode of middle cerebral artery thread occlusion, and rtPA effects were assessed by laser-Doppler flowmetry, [(14)C]iodoantipyrine autoradiography, and triphenyltetrazolium chloride staining. RESULTS AND CONCLUSIONS: We provide evidence that rtPA provokes complex hemodynamic alterations in the ischemic brain tissue, which include an initial hyperperfusion and a more delayed hypoperfusion response. Changes are most pronounced in the periphery of the ischemic infarct, where regional blood flow drops below critical thresholds of tissue viability. Our observations suggest that changes of perfusion may at least partly explain the rtPA-induced increase of infarct size, which has previously been reported and which we also confirmed in the present experiments. Notably, both the secondary hypoperfusion and increase of infarct volume were abolished when rtPA-treated animals received additional heparin infusions. This finding suggests that a secondary hypercoagulability may compromise brain perfusion after rtPA delivery. Accordingly, early treatment with heparin might help to prevent the rtPA-induced changes.

Changes in dehydroepiandrosterone (DHEA) and DHEA-sulfate plasma levels during experimental endotoxinemia in healthy volunteers.

Dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEA-S) have immunomodulatory effects in vitro and in vivo. Additionally, their plasma levels are altered during chronic infection and inflammation. However, it remains unknown whether these steroids are involved in early host responses to infection in humans. We examined DHEA and DHEA-S levels during experimental endotoxinemia, a well established pathophysiological model of bacterial infections in humans. Purified Salmonella abortus equi endotoxin (0.2, 0.4, or 0.8 ng/kg body weight) was injected in a single-blind, placebo-controlled experiment to 17 healthy male volunteers. During the following 12 h, rectal temperature and the plasma levels of ACTH, cortisol, DHEA, DHEA-S, interleukin 6, and tumor necrosis factor alpha were determined. Confirming earlier studies, temperature and cytokine levels showed monophasic, dose-dependent increases in response to endotoxin. In contrast, endocrinological effects of endotoxin showed a complex, biphasic pattern: cortisol levels were not affected by 0. 2 ng/kg but significantly increased during the first 6 h following 0. 4 and 0.8 ng/kg endotoxin, whereas ACTH and DHEA levels were significantly enhanced during the first 6 h following 0.8 ng/kg only. ACTH, DHEA, and cortisol secretion was blunted 6-12 h following 0.8 ng/kg. DHEA-S levels were unaffected during the first 6 h following all dosages, but between 6-12 h after injection they were significantly increased following 0.2 ng/kg, unaffected by 0.4 ng/kg, and significantly decreased following 0.8 ng/kg endotoxin. The present results suggest that similarly to glucocorticoids, the adrenal androgens DHEA and DHEA-S play an important role during early host responses to bacterial infections in humans.

Expression of c-jun, mitogen-activated protein kinase phosphatase-1, caspase-3 and glial fibrillary acidic protein following cortical cold injury in rats: relationship to metabolic disturbances and delayed cell death.

The expression of c-jun, mitogen-activated protein kinase phosphatase-1 (mkp-1), caspase-3 and glial fibrillary acidic protein (gfap) was examined at 1, 3 and 7 days after cortical cold injury in rats by in situ hybridisation and immunocytochemistry. Alterations of gene expression were related to metabolic disturbances and delayed cell death, as revealed by cerebral protein synthesis autoradiography, ATP bioluminescence, pH fluorescence and terminal transferase biotinylated dUTP nick end labelling (TUNEL). Protein synthesis autoradiographies depicted sharply demarcated cortex lesions, which were almost congruent with areas exhibiting ATP depletion (lesion volume: 16.9+/-11.8 mm(3) after 7 days). Lesions were surrounded by a region of tissue alkalosis, which was most prominent 1 day after trauma. Delayed cell injury, as revealed by TUNEL, was noticed in a thin rim around the lesion border on day 1 (tissue volume: 1.7+/-0.8 mm(3)) and, to lesser extent, days 3 and 7 post-lesioning. However, only a small percentage of cells in this area were positive for activated caspase-3 protein. TUNEL(+) cells were further seen in the ventrobasal thalamus after 7 days. In the thalamus, the appearance of DNA-fragmented cells was closely accompanied by activated caspase-3 expression. In situ hybridisations revealed that cell injury both in the peri-lesion rim and ventrobasal thalamus was associated with increased c-jun and gfap, but not mkp-1 and caspase-3 mRNA levels. Gene responses were not confined to areas revealing irreversible cell death: mkp-1 mRNA was bilaterally upregulated in the lesion-remote entorhinal cortex, cingulate cortex and reticular thalamus at 7 days after trauma, and caspase-3 mRNA was slightly, but significantly downregulated in the entorhinal cortex after 3 and 7 days. Gfap mRNA was elevated in all regions exhibiting tissue alkalosis. Our data suggest that delayed cell injury after cortex trauma may be apoptotic in the ventrobasal thalamus, but not the peri-lesion rim. The dissociated responses of c-jun, mkp-1 and caspase-3 mRNAs may represent important factors influencing tissue viability.

Expression of c-fos, junB, c-jun, MKP-1 and hsp72 following traumatic neocortical lesions in rats--relation to spreading depression.

The effects of a traumatic neocortical lesion on c-fos, junB, c-jun, MKP-1 and hsp72 expression were examined by in situ hybridization and immunocytochemistry 1-6 h following transcranial cold injury. The direct current potential was recorded in the injury-remote cortex to evaluate the role of transient direct current shifts, i.e. spreading depressions, in gene expression. In 14 out of 21 injured rats, spreading depression-like depolarizations of the direct current potential were noticed, which were accompanied by a transient decrease in electroencephalographic activity and increase in laser Doppler flow. In seven injured animals, no spontaneous spreading depressions were seen. In animals without spreading depressions, only a short-lasting response of c-fos, junB, c-jun and MKP-1 messenger RNAs as well as c-Fos protein was bilaterally found in the piriform cortex, and--with ipsilateral dominance--the dentate gyrus and hippocampal CA3/4 fields at 1 h after lesioning. In injured animals with spreading depressions however, a strong elevation was seen in layers II-IV and VI of the injury-remote ipsilateral cerebral cortex, which persisted over as long as 6 h. Messenger RNA levels for c-fos, junB and MKP-1 were closely related to the time interval between the last depolarization and the end of experiment. Levels were highest shortly after transient direct current shifts, and decreased thereafter mono-exponentially with half-lives of 48, 75 and 58 min for c-fos, junB and MKP-1 messenger RNAs, respectively. In 6 h animals with spreading depressions, hsp72 messenger RNA was slightly elevated in layer II of the injury-remote cortex, but heat shock protein 72 was not increased. The present results demonstrate that spreading depression is the most prominent factor influencing the trauma-related gene response in the lesion-remote cortical tissue.

Expression of redox factor-1, p53-activated gene 608 and caspase-3 messenger RNAs following repeated unilateral common carotid artery occlusion in gerbils--relationship to delayed cell injury and secondary failure of energy state.

The temporospatial expression pattern of the nuclear DNA repair enzyme redox factor-1 (ref-1), the p53-activated gene (pag) 608 and the effector caspase-3 was examined by in situ hybridization histochemistry in gerbils subjected to two 10-min episodes of unilateral common carotid artery occlusion, separated by 5h. Gene responses were correlated with the metabolic state, as revealed by regional adenosine 5'-triphosphate bioluminescent imaging, and with the degree of histological damage, as assessed by haematoxylin-eosin staining and terminal deoxynucleotidyl transferase-mediated-dUTP nick end labeling (TUNEL), in order to evaluate the role of these genes in the maturation of injury. Focal infarcts developed in the dorsolateral cerebral cortex at the bregma level and the nucleus caudate-putamen within four days after repeated unilateral ischemia, as indicated by a secondary adenosine 5'-triphosphate loss after initial adenosine 5'-triphosphate recovery and by histomorphological signs of pannecrosis. The more caudal cortex at hippocampal levels and the hippocampus (CA1>CA3 area), however, exhibited selective neuronal injury without adenosine 5'-triphosphate depletion. TUNEL+ cells appeared starting 5h after repeated unilateral ischemia. TUNEL+ cells reached maximum levels in the caudate-putamen at 12-24h, but much later in the cortex and hippocampus at two days after ischemia. Remarkably few TUNEL+ cells were noticed in the thalamus, where adenosine 5'-triphosphate state did not recover after reperfusion. Following repeated unilateral ischemia, a transient elevation of ref-1 mRNA was detected after 5h in the cerebral cortex and hippocampal CA1 area. Ref-1 mRNA levels decreased within 12-24h, before the onset of tissue damage. Subsequently, pag608 and caspase-3 mRNA levels increased, closely in parallel with the appearance of DNA fragmented cells, but slightly prior to the deterioration of adenosine 5'-triphosphate state. In the caudate-putamen, pag608 and caspase-3 mRNAs reached maximum levels already 12-24h after repeated common carotid artery occlusion, when DNA fragmentation was most prominent, and declined thereafter. In the cortex and hippocampal CA1-3 areas, where DNA damage appeared more slowly, pag608 and caspase-3 mRNAs were induced starting 24h after ischemia, and remained elevated even after two to four days. The levels of pag608 and caspase-3 mRNAs were similar at rostral and caudal levels of the cortex, as well as in the hippocampal CA1 and CA3 area, although the degree of injury differed considerably between these structures. Notably, pag608 and caspase-3 mRNAs were not elevated in the thalamus after repeated unilateral ischemia. The present report shows a close temporal association between the induction of ref-1, pag608 and caspase-3 mRNAs, the manifestation of cell injury and the secondary adenosine 5'-triphosphate depletion in infarcting brain areas, suggesting (i) that de novo responses of these genes may be involved in the maturation of cell injury and (ii) that apoptotic programs and the secondary deterioration of cerebral energy state may interfere with each other after ischemia.

Relationship between metabolic dysfunctions, gene responses and delayed cell death after mild focal cerebral ischemia in mice.

The evolution of brain injury was examined in mice subjected to focal cerebral ischemia as induced by 30 min of intraluminar thread occlusion of the middle cerebral artery, followed by 3 h to 3 days of reperfusion. Metabolic dysfunctions were studied by 3H-leucine autoradiography for the measurement of cerebral protein synthesis and by regional ATP bioluminescent imaging. Metabolic changes were compared with responses of the genes c-fos, c-jun, heat-shock protein gene (hsp)72, p53-activated gene (pag)608 and caspase-3, which were investigated by in situ hybridization histochemistry and immunocytochemistry, and correlated with the degree of DNA fragmentation, as assessed by the terminal TdT-mediated dUTP-biotin nick end labeling method. Intraluminar thread occlusion led to a reproducible reduction of cerebral laser Doppler flow to 20-30% of control. Thread withdrawal was followed by a short-lasting post-ischemic hyperperfusion to approximately 120%. In non-ischemic control animals, fractional protein synthesis values of 0.81+/-0.26 and 0.94+/-0.23 were obtained. Thread occlusion resulted in a suppression of protein synthesis throughout the territory of the middle cerebral artery after 3 h of reperfusion (0.04+/-0.08 in caudate-putamen and 0.14+/-0.19 in somatosensory cortex, P<0.05). Protein synthesis partly recovered in the cortex after 24 h and 3 days (0.71+/-0.40 and 0.63+/-0.26, respectively), but remained suppressed in the caudate-putamen (0.14+/-0.22 and 0.28+/-0.28). Regional ATP levels did not show any major disturbances at the reperfusion times examined. Thread occlusion resulted in a transient increase of c-fos mRNA levels in ischemic and non-ischemic parts of the cortex and caudate-putamen at 3 h after ischemia, which suggests that spreading depressions were elicited in the tissue. At the same time, c-jun and hsp72 mRNAs were elevated only in ischemic brain areas showing inhibition of protein synthesis. C-fos and c-jun responses completely disappeared within 24 h of reperfusion. Hsp72 mRNA levels remained elevated in the cortex after 24 h, but decreased to basal values in the caudate-putamen. Twenty-four hours after reperfusion, pag608 and caspase-3 mRNA levels increased in the caudate-putamen, where protein synthesis rates were still reduced, and remained elevated even after 3 days. However, pag608 and caspase-3 mRNA levels did not increase in the cortex, where protein synthesis recovered. After 24 h and 3 days, functionally active p20 fragment of caspase-3 was detected in the caudate-putamen, closely associated with the appearance of DNA fragmented cells. Neither activated caspase-3 nor DNA fragmentation were noticed in the cortex.In summary, the suppression of protein synthesis is reversible in the ischemia-resistant cortex following 30 min of thread occlusion in mice, but persists in the vulnerable caudate-putamen. In the caudate-putamen, apoptotic programs are induced, closely in parallel with the manifestation of delayed cell death. Thus, the recovery of protein synthesis may be a major factor influencing tissue survival after transient focal ischemia.

The superoxide dismutase1 (SOD1) G93A mutation does not promote neuronal injury after focal brain ischemia and optic nerve transection in mice.

The superoxide dismutase 1 (SOD1)G93A mouse was recently established as transgenic model of amyotrophic lateral sclerosis. We were interested to know whether the SOD1 G93A mutation promotes neuronal injury after intraluminal middle cerebral artery thread occlusion and/or retinal ganglion cell (RGC) axotomy in mice, which are highly reproducible and clinically relevant in vivo models of acute and subacute neuronal degeneration, respectively. In our experiments, G93A mutant SOD1 neither influenced ischemic injury after 90 or 30 min of focal ischemia, nor had an impact on the severity of RGC degeneration after optic nerve transection, when human SOD1 G93A mutant mice were compared to human wild-type SOD1 mice. Our data indicate that the clinically relevant SOD1 G93A mutation, which leads to amyotrophic lateral sclerosis in humans and mice, does not necessarily worsen neuronal degeneration in other pathologies. Thus, the G93A mutation may be counterbalanced in non-motor neurons of young animals, and region-specific and age-related factors may be necessary so that neurodegeneration is re-enforced.