Mesenchymal derived exosomes enhance recovery of motor function in a monkey model of cortical injury.

BACKGROUND: Exosomes from mesenchymal stromal cells (MSCs) are endosome-derived vesicles that have been shown to enhance functional recovery in rodent models of stroke. OBJECTIVE: Building on these findings, we tested exosomes as a treatment in monkeys with cortical injury. METHODS: After being trained on a task of fine motor function of the hand, monkeys received a cortical injury to the hand representation in primary motor cortex. Twenty-four hours later and again 14 days after injury, monkeys received exosomes or vehicle control. Recovery of motor function was followed for 12 weeks. RESULTS: Compared to monkeys that received vehicle, exosome treated monkeys returned to pre-operative grasp patterns and latency to retrieve a food reward in the first three-five weeks of recovery. CONCLUSIONS: These results provide evidence that in monkeys exosomes delivered after cortical injury enhance recovery of motor function.

The predictive power of diagnostic tests and the effect of prevalence of illness.

There is a great interest in the potential usefulness of biomedical tests in psychiatry, but basic statistical principles required for critical evaluation of their value remain poorly integrated into clinical thinking. We developed a useful scheme for organizing clinical test data so as to permit simple calculations of the sensitivity, specificity, and predictive power of medical tests. Some loss of predictive power is inherent in moving from artificial populations used for test development into more typical clinical settings, where prevalence is usually substantially lower.

Increased activity and phase delay in circadian motility rhythms in geriatric depression. Preliminary observations.

Locomotor activity levels and rhythms of eight hospitalized geriatric unipolar depressed patients (DSM-III criteria) were compared with those of eight healthy elderly controls in a similar environment. Activity was measured using a wrist-worn electronic activity monitor with solid-state memory. Depressed patients had a 29% higher mean total 24-hour activity level, with no change in circadian amplitude or frequency. Daily peak activity (acrophase) averaged 2.05 hours later in depressed patients, with no overlap between the groups. The degree of phase delay correlated significantly with the 4 PM postdexamethasone serum cortisol level. These tentative findings suggest that elderly unipolar depressed patients have prominent chronobiological disturbances in the modulation of activity levels and possibly other physiological processes. These differ strikingly from reported disturbances in younger or bipolar depressed patients.

Basic fibroblast growth factor protects against hypoxia-ischemia and NMDA neurotoxicity in neonatal rats.

Basic fibroblast growth factor (bFGF) is a polypeptide that promotes neuronal survival and blocks excitatory amino acid (EAA) neurotoxicity in vitro at very low concentrations. In the present study, we examined whether systemically administered bFGF could prevent neuronal damage induced by either EAAs or hypoxia-ischemia in vivo. Neuroprotective effects were examined in a neonatal model of hypoxia-ischemia (unilateral ligation of the carotid artery followed by exposure to 8% oxygen for 1.5 h) and following intrastriatal injection of N-methyl-D-aspartate (NMDA) in 7-day-old rats. Intraperitoneal administration of a single dose of bFGF (50-300 micrograms/kg) 30 min before intrastriatal injection of NMDA showed a dose-dependent neuroprotective effect. Repeated doses of bFGF (100 micrograms/kg) both before and after intrastriatal NMDA injection produced a much greater significant protective effect than a single dose administered prior to the injection. Intraperitoneal injection of single dose of 100 micrograms/kg of bFGF 30 min before hypoxia-ischemia reduced neuronal damage by 38% (p = 0.14), while administration of bFGF at a dose of 100 micrograms/kg i.p. three times, 30 min before and 0 and 30 min after hypoxia-ischemia, significantly reduced neuronal damage by 64% (p = 0.004). Systemic administration of bFGF did not change body temperature for up to 3 h. These results show that systemic administration of bFGF can exert neuroprotective effects against both NMDA-induced excitotoxicity and hypoxia-ischemia in vivo.

Intracisternal basic fibroblast growth factor (bFGF) enhances behavioral recovery following focal cerebral infarction in the rat.

Basic fibroblast growth factor (bFGF) is a potent neurotrophic agent that promotes neuronal survival and outgrowth. Previous studies have shown that bFGF, administered intraventricularly or intravenously before or within hours after ischemia, reduces infarct size and neurological deficits in models of focal cerebral ischemia in rats. In the current study, we tested the hypothesis that bFGF, administered at later time points after ischemia, might improve behavioral recovery without affecting infarct size. Mature Sprague-Dawley rats received bFGF (1 microgram/injection) or vehicle by biweekly intracisternal injection for 4 weeks, starting at 1 day following permanent proximal middle cerebral artery (MCA) occlusion. Animals were examined every other day using four different behavioral tests to assess sensorimotor and reflex function. At 4 weeks after ischemia, there was no difference in infarct volume between bFGF- and vehicle-treated animals. There was, however, an enhancement in the rate and degree of behavioral recovery among bFGF-treated animals, as measured by all four tests. There were no apparent side effects of bFGF treatment, except that bFGF-treated animals tended to recover body weight more slowly than did vehicle-treated animals following stroke. The mechanisms of enhancement of behavioral recovery by bFGF require further study, but may include protection against retrograde neuronal death and/or stimulation of neuronal sprouting.

Delayed treatment with intravenous basic fibroblast growth factor reduces infarct size following permanent focal cerebral ischemia in rats.

Basic fibroblast growth factor (bFGF) is a polypeptide that supports the survival of brain cells (including neurons, glia, and endothelia) and protects neurons against a number of toxins and insults in vitro. This factor is also a potent dilator of cerebral pial arterioles in vivo. In previous studies, we found that intraventricularly administered bFGF reduced infarct volume in a model of focal cerebral ischemia in rats. In the current study, bFGF (45 micrograms/kg/h) in vehicle, or vehicle alone, was infused intravenously for 3 h, beginning at 30 min after permanent middle cerebral artery occlusion by intraluminal suture in mature Sprague-Dawley rats. After 24 h, neurological deficit (as assessed by a 0- to 5-point scale, with 5 = most severe) was 2.6 +/- 1.0 in vehicle-treated and 1.5 +/- 1.3 in bFGF-treated rats (mean +/- SD; N = 12 vs. 11; p = 0.009). Infarct volume was 297 +/- 65 mm3 in vehicle- and 143 +/- 135 mm3 in bFGF-treated animals (p = 0.002). During infusion, there was a modest decrease in mean arterial blood pressure but no changes in arterial blood gases or core or brain temperature in bFGF-treated rats. Autoradiography following intravenous administration of 111In-labeled bFGF showed that labeled bFGF crossed the damaged blood-brain barrier to enter the ischemic (but not the nonischemic) hemisphere. Whether the infarct-reducing effects of bFGF depend on intraparenchymal or intravascular mechanisms requires further study.

Basic fibroblast growth factor dilates rat pial arterioles.

Basic fibroblast growth factor (bFGF) is a polypeptide that promotes the survival and differentiation of brain neurons, glia, and endothelial cells. It has been shown recently that intravenously administered bFGF lowers blood pressure by systemic vasodilation; this effect is mediated, in part, by nitric oxide (NO)-dependent mechanisms. In the current study, we directly evaluated the effect of bFGF on pial arterioles of pentobarbital-anesthetized Sprague-Dawley rats (n = 18) using the closed cranial window technique. Basic FGF (5-200 ng/ml) produced dose-dependent vasodilation; maximal vessel diameter (approximately 120% of control) was reached at 100 ng/ml. No vasodilation was found when bFGF was heat inactivated, or preincubated with blocking antibody. Moreover, bFGF-induced vasodilation was attenuated by coadministration of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), consistent with an NO-dependent mechanism. These results suggest that bFGF may play an important role in the regulation of cerebrovascular tone and cerebral blood flow.

Basic fibroblast growth factor protects against excitotoxicity and chemical hypoxia in both neonatal and adult rats.

Basic fibroblast growth factor (bFGF) is a polypeptide growth factor that promotes neuronal survival. We recently found that systemic administration of bFGF protects against both excitotoxicity and hypoxia-ischemia in neonatal animals. In the present study, we examined whether systemically administered bFGF could prevent neuronal death induced by intrastriatal injection of N-methyl-D-aspartate (NMDA) or chemical hypoxia induced by intrastriatal injection of malonate in adult rats and 1-methyl-4-phenylpyridinium (MPP+) in neonatal rats. Systemic administration of bFGF (100 micrograms/kg) for three doses both before and after intrastriatal injection of either NMDA or malonate in adult rats produced a significant neuroprotective effect. In neonatal rats, bFGF produced dose-dependent significant neuroprotective effects against MPP+ neurotoxicity, with a maximal protection of approximately 50% seen with either a single dose of bFGF of 300 micrograms/kg or three doses of 100 micrograms/kg. These results show that systemic administration of bFGF is effective in preventing neuronal injury under circumstances in which the blood-brain barrier may be compromised, raising the possibility that this strategy could be effective in stroke.

Estradiol protects against ischemic injury.

Clinical studies demonstrate that estrogen replacement therapy in postmenopausal women may enhance cognitive function and reduce neurodegeneration associated with Alzheimer's disease and stroke. This study assesses whether physiologic levels of estradiol prevent brain injury in an in vivo model of permanent focal ischemia. Sprague-Dawley rats were ovariectomized; they then were implanted, immediately or at the onset of ischemia, with capsules that produced physiologically low or physiologically high 17beta-estradiol levels in serum (10 or 60 pg/mL, respectively). One week after ovariectomy, ischemia was induced. Estradiol pretreatment significantly reduced overall infarct volume compared with oil-pretreated controls (mean+/-SD: oil = 241+/-88; low = 139+/-91; high = 132+/-88 mm3); this protective effect was regionally specific to the cortex, since no protection was observed in the striatum. Baseline and ischemic regional CBF did not differ between oil and estradiol pretreated rats, as measured by laser Doppler flowmetry. Acute estradiol treatment did not protect against ischemic injury. Our finding that estradiol pretreatment reduces injury demonstrates that physiologic levels of estradiol can protect against neurodegeneration.

Comparison of MRI and CT scans in a group of psychiatric patients.

The authors compared the results of computerized tomography (CT) and magnetic resonance imaging (MRI) scans of 16 psychotic patients with various diagnoses whose neurologic examinations suggested structural brain abnormalities. Blind readings showed a high concordance of findings, including ventricle-to-brain ratios, although MRI appeared superior in visualizing midline structures and identifying atrophic changes. Because it requires no ionizing radiation, MRI allows multiple studies of the same patient, study of family members, and recruitment of unbiased samples of control subjects. Use of MRI may help address questions regarding the specificity and prevalence of brain abnormalities observed with CT in psychotic patients.

Delayed psychosis after right temporoparietal stroke or trauma: relation to epilepsy.

We observed acute onset of delayed psychosis in 8 patients 1 month to 11 years after right temporoparietooccipital (TPO) stroke or trauma. The psychotic disorder included hallucinations and, in some patients delusions and agitation. All patients had spatioconstructional difficulties. None had an earlier psychiatric disorder. Seven of eight patients had clinical seizures, often in close temporal relationship to the psychosis. The pathophysiology of the psychosis may be related to that of the epilepsy.

Radionuclide angiography: a sensitive diagnostic test for anterior circulation ischemia.

Radionuclide angiography, using high resolution equipment, is a sensitive noninvasive, safe, and rapid diagnostic test for ischemia of the anterior circulation of the brain. The test permits recognition of focally increased or decreased circulation immediately following the onset of a neurologic deficit. The sensitivity of the test is improved by using multiple projections of the head. The distribution of the anterior cerebral artery is best seen in the anterior projection; the lateral projection is used to resolve the superior and inferior divisions of the middle cerebral artery or to identify multiple regions of ischemia. Both projections should be used routinely.

Petechial hemorrhages accompanying lobar hemorrhage: detection by gradient-echo MRI.

Based on the pathologic observation that severe cerebral amyloid angiopathy is often accompanied by multiple petechial hemorrhages, we prospectively obtained gradient-echo MRI on 15 elderly patients with lobar hemorrhage on CT. Nine of the 15 demonstrated accompanying petechial hemorrhages restricted to the cortical or corticosubcortical regions. No similar lesions were present on gradient-echo MRI in 10 elderly control patients. These findings suggest that cerebral amyloid angiopathy might be neuroradiologically diagnosed and staged during life.

Delayed stroke following carotid occlusion.

A 60-year-old patient suffered a lethal hemispheric infarction 3 days after angiographically documented occlusion of the ipsilateral cervical internal carotid artery and while receiving anticoagulant therapy. Pathologic evidence is consistent with embolism from the distal "tail" of a propagated carotid thrombus as the mechanism of his stroke.

The clinical spectrum of cerebral amyloid angiopathy: presentations without lobar hemorrhage.

Cerebral amyloid angiopathy is a common cause of spontaneous lobar hemorrhage in elderly patients. We discuss seven patients with amyloid angiopathy presenting without major lobar hemorrhage. The patients' presentations fell into two groups: recurrent transient neurologic symptoms and rapidly progressive dementia. The cases with transient episodes had a spread of symptoms to contiguous body areas during episodes. Each had evidence of small hemorrhage or subsequent large hemorrhage in the cortical location corresponding to the symptoms, suggesting petechial hemorrhage with focal seizure as the cause of the transient spells. Three cases of dementia developed with relatively rapid time courses, progressing from intact baseline to profound dementia in spans of a few days to 2 years. Pathologic abnormalities, in addition to amyloid angiopathy, included patchy white matter demyelination and tissue loss, petechial cortical hemorrhages, cortical infarctions, and a variable degree of neuritic plaques and neurofibrillary tangles. The clinical spectrum of cerebral amyloid angiopathy includes these two neurologic syndromes.

Time window of intracisternal osteogenic protein-1 in enhancing functional recovery after stroke.

Osteogenic protein-1 (OP-1, BMP-7) is a member of the bone morphogenetic protein subfamily of the TGF-ss superfamily that selectively stimulates dendritic neuronal outgrowth. In previous studies, we found that the intracisternal injection of OP-1, starting at one day after stroke, enhanced sensorimotor recovery of the contralateral limbs following unilateral cerebral infarction in rats. In the current study, we further explored the time window during which intracisternal OP-1 enhances sensorimotor recovery, as assessed by limb placing tests. We found that intracisternal OP-1 (10 microg) given 1 and 3 days, or 3 and 5 days, but not 7 and 9 days after stroke, significantly enhanced recovery of forelimb and hindlimb placing. There was no difference in infarct volume between vehicle- and OP-1-treated animals. The mechanism of OP-1 action might be stimulation of new dendritic sprouting in the remaining uninjured brain.

Myocyte-specific enhancer binding factor 2C expression in gerbil brain following global cerebral ischemia.

Myocyte-specific enhancer binding factor 2 (MEF2C) is a transcription factor expressed at high levels in brain. In this study, the distribution of MEF2C expression in brain was studied in normal adult gerbils and in adult gerbils subjected to 10 min of global cerebral ischemia. In normal animals, MEF2C-immunoreactivity and messenger RNA expression were detected in cortex, hippocampus, caudate-putamen, thalamus, hypothalamus, and amygdala. Within the hippocampus, MEF2C-immunoreactivity and MEF2C messenger RNA were found in interneurons scattered through the CA fields, a subset of which are parvalbumin-immunoreactive. MEF2C-immunoreactivity and MEF2C messenger RNA were also present in granule cells in the dentate gyrus. MEF2C-immunoreactivity was also detected in microglia in the hippocampus. After transient forebrain ischemia, CA1 pyramidal neurons, which are MEF2C-negative, degenerate whereas MEF2C-positive interneurons survive. Our results thus indicate that MEF2C is a marker for hippocampal neurons that are resistant to ischemia. It remains to be determined whether MEF2C plays a direct role in protecting the neurons that express it from ischemic injury. In addition, MEF2C-immunoreactivity is present in microglia, and, after ischemia, there were increased numbers of MEF2C-immunoreactive microglia in CA1, so MEF2C-immunoreactivity is a marker of both resting and activated microglia.

Intravenous basic fibroblast growth factor (bFGF) decreases DNA fragmentation and prevents downregulation of Bcl-2 expression in the ischemic brain following middle cerebral artery occlusion in rats.

In previous studies, we showed that basic fibroblast growth factor (bFGF) reduced infarct volume when infused intravenously in animal models of focal cerebral ischemia. In the current study, we examined the potential mechanism of infarct reduction by bFGF, especially effects on apoptosis within the ischemic brain. We found that bFGF decreased DNA fragmentation in the ischemic hemisphere, as assessed by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) histochemical methods combined with morphological criteria. bFGF also prevented reduction of immunoreactivity of the anti-apoptotic protein Bcl-2 in the ischemic hemisphere, but did not alter immunoreactivity of the pro-apoptotic proteins Bax, Caspase-1, or Caspase-3. These changes in TUNEL histochemistry and Bcl-2 immunoreactivity were especially prominent in cortex at the borders ('penumbra') of infarcts, spared by bFGF treatment. We conclude that the infarct-reducing effects of bFGF may be due, in part, to prevention of downregulation of Bcl-2 expression and decreased apoptosis in the ischemic brain.

Partial purification and characterization of a neurite-promoting factor from the injured goldfish optic nerve.

We have partially purified and characterized a neurite-promoting factor derived from the injured goldfish optic nerve (ON). This factor is secreted into conditioned media (CM) by the injured, but not intact goldfish ON, and has potent outgrowth-promoting effects on neurons of the embryonic mammalian brain. Based on its elution properties on ion-exchange and gel-filtration chromatography, this factor appears to be an acidic protein of Mr ca. 26 kilodaltons (kDa) that is distinct from previously characterized growth factors with described effects on mammalian CNS neurons.

Temporal, differential and regional expression of mRNA for basic fibroblast growth factor in the developing and adult rat brain.

The expression of basic fibroblast growth factor (bFGF) mRNA and bFGF receptor mRNA was investigated in developing rat brain. In embryonic rat brain days 13-21 (E13-E21), an abundant 1.8 kb bFGF mRNA was detected. Expression of 1.8 kb bFGF mRNA was the highest at E17 to E19 and was relatively undetectable 20 days after birth. However, very little mitogenic activity was associated with prenatal brain. On the other hand, multiple bFGF mRNA species of 6.0, 3.7, 2.5, 1.8, 1.6, 1.4 and 1.0 kb were detected in total adult rat brain and a significant amount of mitogenic activity was present. Differential and spatial bFGF mRNA expression was found in different parts of developing rat brain. Embryonic hypothalamus was found to contain the 1.8 kb bFGF mRNA while the 6.0 kb bFGF mRNA transcript was predominant in adult hypothalamus. Adult pituitary and cortex transcribed the lower molecular weight mRNAs but not the 6.0 kb mRNA. Expression of high-affinity bFGF receptor (flg) mRNA was found to be temporally regulated. flg 4.3 kb mRNA expression was high in embryonic rat brain (E13-E19). There appears to be coordinate expression between the 1.8 kb bFGF mRNA and flg. These results suggest that the expression of basic FGF mRNA is complex since it is both temporally and differentially regulated with different species being expressed at different times in development.