Methamphetamine potentiates ischemia/reperfusion insults after transient middle cerebral artery ligation

Wasp venom from Vespa magnifica acts as a neuroprotective agent to alleviate neuronal damage after stroke in rats

CONTEXT

Acute ischaemic stroke (AIS) is a major cause of disability and death, which is a serious threat to human health and life. Wasp venom extracted from Vespa magnifica Smith (Vespidae) could treat major neurological disorders.

OBJECTIVE

This study investigated the effects of wasp venom on AIS in rats.

MATERIAL AND METHODS

We used a transient middle cerebral artery occlusion (MCAO) model in Sprague-Dawley rats (260-280 g, n = 8-15) with a sham operation group being treated as negative control. MCAO rats were treated with wasp venom (0.05, 0.2 and 0.6 mg/kg, i.p.) using intraperitoneal injection. After treatment 48 h, behavioural tests, cortical blood flow (CBF), TTC staining, H&E staining, Nissl staining, TUNEL assay, immunohistochemistry (IHC) and ELISA were employed to investigate neuroprotective effects of wasp venom.

RESULTS

Compared with the MCAO group, wasp venom (0.6 mg/kg) improved neurological impairment, accelerated CBF recovery (205.6 ± 52.92 versus 216.7 ± 34.56), reduced infarct volume (337.1 ± 113.2 versus 140.7 ± 98.03) as well as BBB permeability as evidenced by changes in claudin-5 and AQP4. In addition, function recovery of stroke by wasp venom treatment was associated with a decrease in TNF-α, IL-1β, IL-6 and inhibition activated microglia as well as apoptosis. Simultaneously, the wasp venom regulated the angiogenesis factors VEGF and b-FGF in the brain.

CONCLUSIONS

Wasp venom exhibited a potential neuroprotective effect for AIS. In the future, we will focus on determining whether the observed actions were due to a single compound or the interaction of multiple components of the venom.

Genistein attenuates brain damage induced by transient cerebral ischemia through up-regulation of Nrf2 expression in ovariectomized rats

OBJECTIVE

Postmenopausal women possess higher incidence of stroke and worse prognosis. Although estrogen replacement therapy has obvious neuroprotective effects against stroke, it is always accompanied with several adverse effects and undesired outcomes. Genistein, a natural phytoestrogen, has been indicated to be a potential neuroprotective alternative for postmenopausal women against stroke. However, the role and mechanism of genistein's neuroprotective effects against stroke in ovariectomized rats have rarely been explored.

METHODS

In this study, ovariectomized rats were treated with genistein (10 mg/kg) or vehicle daily for two weeks before they received middle cerebral artery occlusion (MCAO) and reperfusion. After 72 hours of reperfusion, the neurological function was evaluated by Garcia test, infarct volume was detected by 2,3,5-triphenyltetrazolium chloride staining, and neuronal damage was detected by Nissl staining. In addition, ROS production and the expression of Nrf2, NQO1 and cleaved-Caspase3 in the ischemic penumbra were detected.

RESULTS

The results showed that genistein treatment significantly improved the neurological outcome, reduced infarct volume, increased Nrf2 and NQO1 expression, and reduced ROS production and cleaved-Caspase3 expression in ovariectomized rats.

DISCUSSION

Our findings indicated that treatment with genistein could alleviated oxidative stress injury induced by cerebral ischemia in ovariectomized rats via promoting Nrf2 and NQO1 expression, which provide a new molecular mechanism for the neuroprotective effects of genistein against stroke in postmenopausal women.

Baicalin suppresses IL-1β-induced expression of inflammatory cytokines via blocking NF-κB in human osteoarthritis chondrocytes and shows protective effect in mice osteoarthritis models

Osteoarthritis (OA) is a degenerative joint disease with an inflammatory component that drives the degradation of cartilage extracellular matrix. Baicalin, a predominant flavonoid isolated from the dry root of Scutellaria baicalensis Georgi, has been reported to have anti-inflammatory effects. However, the anti-inflammatory effects of baicalin on OA have not been reported. Our study aimed to investigate the effect of baicalin on OA both in vitro and in vivo. In vitro, human OA chondrocytes were pretreated with baicalin (10, 50, 100μM) for 2h and subsequently stimulated with IL-1β for 24h. Production of NO and PGE2 were evaluated by the Griess reaction and ELISAs. The mRNA expression of COX-2, iNOS, MMP-3, MMP-13, ADAMTS-5, aggrecan and collagen-II were measured by real-time PCR. The protein expression of COX-2, iNOS, MMP-3, MMP-13, ADAMTS-5, p65, p-p65, IκBα and p-IκBα was detected by Western blot. The protein expression of collagen-II was evaluated by immunofluorescence. Luciferase activity assay was used to assess the relative activity of NF-kB. In vivo, the severity of OA was determined by histological analysis. We found that baicalin significantly inhibited the IL-1β-induced production of NO and PGE2, expression of COX-2, iNOS, MMP-3, MMP-13 and ADAMTS-5 and degradation of aggrecan and collagen-II. Furthermore, baicalin dramatically suppressed IL-1β-stimulated NF-κB activation. In vivo, treatment of baicalin not only prevented the destruction of cartilage but also relieved synovitis in mice OA models. Taken together, these results suggest that baicalin may be a potential agent in the treatment of OA.

Intracerebral Xenotransplantation of GFP Mouse Bone Marrow Stromal Cells in Intact and Stroke Rat Brain: Graft Survival and Immunologic Response

The present study characterized survival and immunologic response of bone marrow stromal cells (BMSCs) following transplantation into intact and stroke brains. In the first study, intrastriatal transplantation of BMSC (60,000 in 3 μl) or vehicle was performed in normal adult Sprague-Dawley male rats that subsequently received daily cyclosporin A (CsA, 10 mg/kg, IP in 3 ml) or vehicle (olive oil, similar volume) starting on day of surgery up to 3 days posttransplantation. Animals were euthanized at 3 or 30 days posttransplantation and brains were processed either for green fluorescent protein (GFP) microscopy or flow cytometry (FACS). Both GFP epifluorescence and FACS scanning revealed GFP+ BMSCs in both groups of transplanted rats with or without CsA, although significantly increased (1.6- to 3-fold more) survival of GFP+ BMSCs was observed in the immunosuppressed animals. Further histologic examination revealed widespread dispersal of BMSCs away from the graft core accompanied by many long outgrowth processes in non-CsA-transplanted animals, whereas a very dense graft core, with cells expressing only sporadic short outgrowth processes, was observed in CsA-transplanted animals. There were no detectable GFP+ BMSCs in nontrans-planted rats that received CsA or vehicle. Immunologic response via FACS analysis revealed a decreased presence of cytotoxic cells, characterized by near complete absence of CD8+ cells, and lack of activation depicted by low CD69 expression in CsA-treated transplanted animals. In contrast, elevated levels of CD8+ cells and increased activation of CD69 expression were observed in transplanted animals that received vehicle alone. CD4+ helper cells were almost nondetectable in transplanted rats that received CsA, but also only minimally elevated in transplanted rats that received vehicle. Nontransplanted rats that received either CsA or vehicle displayed very minimal detectable levels of all three lymphocyte markers. In the second study, a new set of male Sprague-Dawley rats initially received bilateral stereotaxic intrastriatal transplantation of BMSCs and 3 days after were subjected to unilateral transient occlusion of middle cerebral artery. The animals were allowed to survive for 3 days after stroke without CsA immunosuppression. Epifluorescence microscopy revealed significantly higher (5-fold more) survival of transplanted GFP+ BMSCs in the stroke striatum compared with the intact striatum. The majority of the grafts remained within the original dorsal striatal transplant site, characterized by no obvious migration in intact striatum, but with long-distance migration along the ischemic penumbra in the stroke striatum. Moreover, FACS scanning analyses revealed low levels of immunologic response of grafted BMSCs in both stroke and intact striata. These results, taken together, suggest that xenotransplantation of mouse BMSCs into adult rats is feasible. Immunosuppression therapy can enhance xenograft survival and reduce graft-induced immunologic response; however, in the acute phase posttransplantation, BMSCs can survive in intact and stroke brain, and may even exhibit long-distance migration and increased outgrowth processes without immunosuppression.

Chronic methamphetamine exposure prior to middle cerebral artery occlusion increases infarct volume and worsens cognitive injury in Male mice

Emerging evidence indicates that methamphetamine (MA) abuse can impact cardiovascular disease. In humans, MA abuse is associated with an increased risk of stroke as well as an earlier age at which the stroke occurs. However, little is known about how chronic daily MA exposure can impact ischemic outcome in either humans or animal models. In the present study, mice were injected with MA (10 mg/kg, i.p.) or saline once daily for 10 consecutive days. Twenty-four hours after the final injection, mice were subjected to transient middle cerebral artery occlusion (tMCAO) for one hour followed by reperfusion. Mice were tested for novel object memory at 96 h post-reperfusion, just prior to removal of brains for quantification of infarct volume using 2,3,5-Triphenyltetrazolium Chloride (TTC) staining. Mice treated with MA prior to tMCAO showed decreased object memory recognition and increased infarct volume compared to saline-treated mice. These findings indicate that chronic MA exposure can worsen both cognitive and morphological outcomes following cerebral ischemia.

Drugs of abuse and blood-brain barrier endothelial dysfunction: A focus on the role of oxidative stress

Psychostimulants and nicotine are the most widely abused drugs with a detrimental impact on public health globally. While the long-term neurobehavioral deficits and synaptic perturbations are well documented with chronic use of methamphetamine, cocaine, and nicotine, emerging human and experimental studies also suggest an increasing incidence of neurovascular complications associated with drug abuse. Short- or long-term administration of psychostimulants or nicotine is known to disrupt blood-brain barrier (BBB) integrity/function, thus leading to an increased risk of brain edema and neuroinflammation. Various pathophysiological mechanisms have been proposed to underlie drug abuse-induced BBB dysfunction suggesting a central and unifying role for oxidative stress in BBB endothelium and perivascular cells. This review discusses drug-specific effects of methamphetamine, cocaine, and tobacco smoking on brain microvascular crisis and provides critical assessment of oxidative stress-dependent molecular pathways focal to the global compromise of BBB. Additionally, given the increased risk of human immunodeficiency virus (HIV) encephalitis in drug abusers, we have summarized the synergistic pathological impact of psychostimulants and HIV infection on BBB integrity with an emphasis on unifying role of endothelial oxidative stress. This mechanistic framework would guide further investigations on specific molecular pathways to accelerate therapeutic approaches for the prevention of neurovascular deficits by drugs of abuse.

Comparison of brain white matter hyperintensities in methamphetamine and methadone dependent patients and healthy controls

Background:

Previous studies have proven the development of white matter hyperintensities (WMH) in methamphetamine and opioid users. Opiates and methamphetamines (MA) are the most common addictive agents in Iran. The adverse effects of drugs on the CNS is of concern to specialists and researchers, and given that the neurotoxicity associated with methamphetamine is greater than opioids, it is hypothesized that the severity of WMH in patients with methamphetamine dependence is more than opioid drug-dependent individuals.

Objectives:

To our knowledge, this is the first research comparing the effect of methamphetamine and methadone (M) on the brain.

Patients and Methods:

In a historical cohort study, we compared WMH in the brain MRI of 50 methamphetamine-dependent patients, 50 methadone-dependent patients and 50 healthy volunteers who were matched for age, sex and dominant hand.

Results:

WMH was detected in 18 methamphetamine users, in 12 methadone users and in seven controls (P = 0.038). The site of brain lesions in MA users was mostly in the frontal lobe in 17 cases, in M users in the frontal lobe in 12 cases and in the control group, it was in the parietal lobe in four cases (P=0.001). The frontal lobes were the predominant locations of WMH in MA and M groups (P = 0.001). The frequency of brain lesions was mostly in the deep WM in 18 cases in MA users, in 12 cases in M users and in two cases in the control group (P=0.007). Hyper-signal foci of deep WM in the MA group were grade I (punctuate) in 12 cases, grade II (beginning confluence) in five cases and grade III (large confluent) in four cases. In the M group, there were six cases in grade I, three cases in grade II and one case in grade III. In the control group, there were three grade I cases, two grade II cases, and no grade III cases. Except for periventricular WMH (P = 0.13), there were statistical significant differences in the deep WMH (P = 0.007) and subcortex WMH (P = 0.01) between the three groups. The history of using other drugs and the duration of MA and M consumption were similar. The prevalence of brain lesions was generally higher in both drug user groups compared with the healthy controls. Increased WMH in the MA group was higher than the M group.

Conclusions:

A greater number of blood flow defects and ischemic lesions in the brain of MA users compared to opiate users may explain the prevalence of psychiatric disorders in these patients.

In vivo evidence of methamphetamine induced attenuation of brain tissue oxygenation as measured by EPR oximetry

Abuse of methamphetamine (METH) is a major and significant societal problem in the US, as a number of studies have suggested that METH is associated with increased cerebrovascular events, hemorrhage or vasospasm. Although cellular and molecular mechanisms involved in METH-induced toxicity are not completely understood, changes in brain O₂ may play an important role and contribute to METH-induced neurotoxicity including dopaminergic receptor degradation. Given that O₂ is the terminal electron acceptor for many enzymes that are important in brain function, the impact of METH on brain tissue pO₂ in vivo remains largely uncharacterized. This study investigated striatal tissue pO₂ changes in male C57BL/6 mice (16-20 g) following METH administration using EPR oximetry, a highly sensitive modality to measure pO₂ in vivo, in situ and in real time. We demonstrate that 20 min after a single injection of METH (8 mg/kg i.v.), the striatal pO₂ was reduced to 81% of the pretreatment level and exposure to METH for 3 consecutive days further attenuated striatal pO₂ to 64%. More importantly, pO₂ did not recover fully to control levels even 24 h after administration of a single dose of METH and continual exposure to METH exacerbates the condition. We also show a reduction in cerebral blood flow associated with a decreased brain pO₂ indicating an ischemic condition. Our findings suggests that administration of METH can attenuate brain tissue pO₂, which may lead to hypoxic insult, thus a risk factor for METH-induced brain injury and the development of stroke in young adults.

The effects of different doses of estradiol (E2) on cerebral ischemia in an in vitro model of oxygen and glucose deprivation and reperfusion and in a rat model of middle carotid artery occlusion

BACKGROUND

Because neuroprotective effects of estrogen remain controversial, we aimed to investigate the effect of different doses of estradiol (E2) on cerebral ischemia using both in vivo and in vitro experiments.

RESULTS

PC12 cells were cultured at physiological (10 nM and 20 nM) or pharmacological (10 μM and 20 μM) dosages of E2 for 24 hours (h). The results of 5-bromodeoxyuridine (Brdu) incorporation and flow cytometric analysis showed that physiological doses of E2 enhanced cell proliferation and pharmacological doses of E2 inhibited cell proliferation. After the cells were exposed to oxygen and glucose deprivation (OGD) for 4 h and reperfusion for 20 h, the results of 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyl tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, flow cytometric analysis and Western blot analysis showed that physiological doses of E2 enhanced cell viability, reduced cell apoptosis and decreased the expression of pro-apoptotic protein caspase-3. In contrast, pharmacological doses of E2 decreased cell viability and induced cell apoptosis. In vivo, adult ovariectomized (OVX) female rats received continuous subcutaneous injection of different doses of E2 for 4 weeks. Transient cerebral ischemia was induced for 2 h using the middle cerebral artery occlusion (MCAO) technique, followed by 22 h of reperfusion. The results of Garcia test, 2, 3, 5-triphenyltetrazolium chloride (TTC) staining showed that 6 μg/kg and 20 μg/kg E2 replacement induced an increase in neurological deficit scores, a decrease in the infarct volume and a reduction in the expression of caspase-3 when compared to animals in the OVX group without E2 treatment. However, 50 μg/kg E2 replacement treatment decreased neurological deficit scores, increased the infarct volume and the expression of caspase-3 when compared to animals in the control group and 6 up/kg or 20 μg/kg E2 replacement group.

CONCLUSION

We conclude that physiological levels of E2 exhibit neuroprotective effects on cerebral ischemia; whereas, pharmacological or supraphysiological doses of E2 have damaging effects on neurons after cerebral ischemia.

Methamphetamine alters reference gene expression in nigra and striatum of adult rat brain

The nigrostriatal dopaminergic system is a major lesion target for methamphetamine (MA), one of the most addictive and neurotoxic drugs of abuse. High doses of MA alter the expression of a large number of genes. Reference genes (RGs) are considered relatively stable and are often used as standards for quantitative real-time PCR (qRT-PCR) reactions. The purpose of this study was to determine whether MA altered the expression of RGs and to identify the appropriate RGs for gene expression studies in animals receiving MA. Adult male Sprague-Dawley rats were treated with high doses of MA or saline. Striatum and substantia nigra were harvested at 2h or 24h after MA administration. The expression and stability of 10 commonly used RGs were examined using qRT-PCR and then evaluated by geNorm and Normfinder. We found that MA altered the expression of selected RGs. These candidate RGs presented differential stability in the striatum and in substantia nigra at both 2h and 24h after MA injection. Selection of an unstable RG as a standard altered the significance of tyrosine hydroxylase (TH) mRNA expression after MA administration. In conclusion, our data show that MA site- and time-dependently altered the expression of RGs in nigrostriatal dopaminergic system. These temporal and spatial factors should be considered when selecting appropriate RGs for interpreting the expression of target genes in animals receiving MA.

Amphetamine challenge decreases yohimbine binding to α2 adrenoceptors in Landrace pig brain

RATIONALE

The noradrenaline (NA) system is implicated in neurodegenerative and psychiatric disorders; however, our understanding is impaired by the lack of well-validated radioligands to assess NA function and release. Yohimbine, an α2 adrenoceptor antagonist, has recently been developed as a carbon-11 [11C]-labeled radioligand for positron emission tomography (PET) imaging studies.

OBJECTIVES

Here we explore the hypothesis that yohimbine can be used as an in vivo tracer of NA receptor binding and release during amphetamine challenges in Landrace pigs.

METHODS

Pigs underwent baseline PET scans with [11C]yohimbine and were then challenged with 10 mg/kg d-amphetamine 20 min prior to a second [11C]yohimbine scan. Using the Logan analysis model, volumes of distribution were calculated from fits of the kinetic data 25-90 min post-yohimbine injection.

RESULTS

Amphetamine decreased [11C]yohimbine volume of distribution in the brain regions under investigation, including the thalamus, caudate nucleus, and cortical regions.

CONCLUSION

These data suggest that the binding of [11C]yohimbine to α2 adrenoceptors may be displaceable by increases in synaptic concentrations of the endogenous ligand, NA, and possibly dopamine, suggesting the possibility that [11C]yohimbine may be used as a surrogate marker of NA release in vivo.

Suppression of endogenous PPARγ increases vulnerability to methamphetamine-induced injury in mouse nigrostriatal dopaminergic pathway

RATIONALE

Methamphetamine is a commonly abused drug and dopaminergic neurotoxin. Repeated administration of high doses of methamphetamine induces programmed cell death, suppression of dopamine release, and reduction in locomotor activity. Previous studies have shown that pretreatment with peroxisome proliferator-activated receptor gamma (PPARγ) agonist reduced methamphetamine-induced neurodegeneration.

OBJECTIVES

The purpose of this study was to examine the role of endogenous PPARγ in protecting against methamphetamine toxicity.

METHODS

Adeno-associated virus (AAV) encoding the Cre recombinase gene was unilaterally injected into the left substantia nigra of loxP-PPARγ or control wild-type mice. Animals were treated with high doses of methamphetamine 1 month after viral injection. Behavioral tests were examined using rotarod and rotometer. In vivo voltammetry was used to examine dopamine release/clearance and at 2 months after methamphetamine injection.

RESULTS

Administration of AAV-Cre selectively removed PPARγ in left nigra in loxP-PPARγ mice but not in the wild-type mice. The loxP-PPARγ/AAV-Cre mice that received methamphetamine showed a significant reduction in time on the rotarod and exhibited increased ipsilateral rotation using a rotometer. The peak of dopamine release induced by local application of KCl and the rate of dopamine clearance were significantly attenuated in the left striatum of loxP-PPARγ/AAV-Cre animals. Tyrosine hydroxylase immunoreactivity was reduced in the left, compared to right, nigra, and dorsal striatum in loxP-PPARγ/AAV-Cre mice receiving high doses of methamphetamine.

CONCLUSION

A deficiency in PPARγ increases vulnerability to high doses of methamphetamine. Endogenous PPARγ may play an important role in reducing methamphetamine toxicity in vivo.

Low dose methamphetamine mediates neuroprotection through a PI3K-AKT pathway

High doses of methamphetamine induce the excessive release of dopamine resulting in neurotoxicity. However, moderate activation of dopamine receptors can promote neuroprotection. Therefore, we used in vitro and in vivo models of stroke to test the hypothesis that low doses of methamphetamine could induce neuroprotection. We demonstrate that methamphetamine does induce a robust, dose-dependent, neuroprotective response in rat organotypic hippocampal slice cultures exposed to oxygen-glucose deprivation (OGD). A similar dose dependant neuroprotective effect was observed in rats that received an embolic middle cerebral artery occlusion (MCAO). Significant improvements in behavioral outcomes were observed in rats when methamphetamine administration delayed for up to 12 h after MCAO. Methamphetamine-mediated neuroprotection was significantly reduced in slice cultures by the addition of D1 and D2 dopamine receptor antagonist. Treatment of slice cultures with methamphetamine resulted in the dopamine-mediated activation of AKT in a PI3K dependant manner. A similar increase in phosphorylated AKT was observed in the striatum, cortex and hippocampus of methamphetamine treated rats following MCAO. Methamphetamine-mediated neuroprotection was lost in rats when PI3K activity was blocked by wortmannin. Finally, methamphetamine treatment decreased both cleaved caspase 3 levels in slice cultures following OGD and TUNEL staining within the striatum and cortex in rats following transient MCAO. These data indicate that methamphetamine can mediate neuroprotection through activation of a dopamine/PI3K/AKT-signaling pathway.

Post-treatment with amphetamine enhances reinnervation of the ipsilateral side cortex in stroke rats

Amphetamine (AM) treatment has been shown to alter behavioral recovery after ischemia caused by embolism, permanent unilateral occlusion of the common carotid and middle cerebral arteries, or unilateral sensorimotor cortex ablation in rats. However, the behavioral results are inconsistent possibly due to difficulty controlling the size of the lesion before treatment. There is also evidence that AM promotes neuroregeneration in the cortex contralateral to the infarction; however, the effects of AM in the ipsilateral cortex remain unclear. The purpose of this study was to employ T2-weighted imaging (T2WI) to establish controlled criteria for AM treatment and to examine neuroregenerative effects in both cortices after stroke. Adult rats were anesthetized, and the right middle cerebral artery was ligated for 90 min to generate lesions in the ipsilateral cortex. Animals were separated into two equal treatment groups (AM or saline) according to the size of infarction, measured by T2WI at 2days after stroke. AM or saline was administered to stroke rats every third day starting on day 3 for 4weeks. AM treatment significantly reduced neurological deficits, as measured by body asymmetry and Bederson's score. T2WI and diffusion tensor imaging (DTI) were used to examine the size of infarction and axonal reinnervation, respectively, before and following treatment on days 2, 10 and 25 after stroke. AM treatment reduced the volume of tissue loss on days 10 and 25. A significant increase in fractional anisotropy ratio was found in the ipsilateral cortex after repeated AM administration, suggesting a possible increase in axonal outgrowth in the lesioned side cortex. Western analysis indicated that AM significantly increased the expression of synaptophysin ipsilaterally and neurofilament bilaterally. AM also enhanced matrix metalloproteinase (MMP) enzymatic activity, determined by MMP zymography in the lesioned side cortex. qRT-PCR was used to examine the expression of trophic factors after the 1st and 2nd doses of AM or saline injection. The expression of BDNF, but not BMP7 or CART, was significantly enhanced by AM in the lesioned side cortex. In conclusion, post-stroke treatment with AM facilitates behavioral recovery, which is associated with an increase in fractional anisotropy activity, enhanced fiber growth in tractography, synaptogenesis, upregulation of BDNF, and MMP activity mainly in the lesioned cortex. Our data suggest that the ipsilateral cortex may be the major target of action in stroke brain after AM treatment.

Methamphetamine causes sustained depression in cerebral blood flow

The use prevalence of the highly addictive psychostimulant methamphetamine (MA) has been steadily increasing over the past decade. MA abuse has been associated with both transient and permanent alterations in cerebral blood flow (CBF), hemorrhage, cerebrovascular accidents and death. To understand MA-induced changes in CBF, we exposed C56BL/6 mice to an acute bolus of MA (5mg/kg MA, delivered IP). This elicited a biphasic CBF response, characterized by an initial transient increase (~ 5 minutes) followed by a prolonged decrease (~ 30 minutes) of approximately 25% relative to baseline CBF--as measured by laser Doppler flowmetry over the somatosensory cortex. To assess if this was due to catecholamine derived vasoconstriction, phentolamine, an α-adrenergic antagonist was administered prior to MA treatment. This reduced the initial increase in CBF but failed to prevent the subsequent, sustained decrease in CBF. Consistent with prior reports, MA caused a transient increase in mean arterial blood pressure, body temperature and respiratory rate. Elevated respiratory rate resulted in hypocapnia. When respiratory rate was controlled by artificially ventilating mice, blood PaCO(2) levels after MA exposure remained unchanged from physiologic levels, and the MA-induced decrease in CBF was abolished. In vivo two-photon imaging of cerebral blood vessels revealed sustained MA-induced vasoconstriction of pial arterioles, consistent with laser Doppler flowmetry data. These findings show that even a single, acute exposure to MA can result in profound changes in CBF, with potentially deleterious consequences for brain function.

Methamphetamine potentiates behavioral and electrochemical responses after mild traumatic brain injury in mice

We previously demonstrated that high doses of methamphetamine (MA) exacerbate damage induced by severe brain trauma. The purpose of the present study was to examine if MA, at low dosage, affected abnormalities in locomotor activity and dopamine turnover in a mouse model of mild traumatic brain injury (mTBI). Adult male CD1 mice were treated with MA (5 mg/kgi.p.) or vehicle 30-min prior to mTBI, conducted by dropping a 30 g metal weight onto the temporal skull, anterior the right ear. At 15 min after mTBI, animals were put into locomotor activity chambers for up to 72 h. During the first 3 h, mTBI alone, compared with vehicle control, did not alter total distance travelled. Treatment with MA significantly increased locomotor activity in the control animals during the first 3 h; mTBI reduced MA-induced hyperactivity. In contrast, at 2 and 3 days after injury, mTBI or MA alone reduced locomotor activity. Co-treatment with MA and mTBI further reduced this activity, suggesting a differential and temporal behavioral interaction between MA and mTBI during acute and subacute phases after injury. Dopamine and DOPAC levels in striatal tissue were analyzed using HPLC-ECD. At 1h after mTBI or injection, DA was not altered but DOPAC level and DOPAC/DA turnover ratios were significantly reduced. Co-treatment with MA further reduced the DOPAC/DA ratio. At 36 h after injury, mTBI increased tissue DA levels, but reduced DOPAC levels and DOPAC/DA ratios. Co-treatment with MA further reduced DOPAC/DA ratios in striatum. In conclusion, our data suggest that low dosage of MA worsens the suppression of locomotor responses and striatal dopamine turnover after mTBI.

Amphetamine and environmentally induced hyperthermia differentially alter the expression of genes regulating vascular tone and angiogenesis in the meninges and associated vasculature

An amphetamine (AMPH) regimen that does not produce a prominent blood-brain barrier breakdown was shown to significantly alter the expression of genes regulating vascular tone, immune function, and angiogenesis in vasculature associated with arachnoid and pia membranes of the forebrain. Adult-male Sprague-Dawley rats were given either saline injections during environmentally-induced hyperthermia (EIH) or four doses of AMPH with 2 h between each dose (5, 7.5, 10, and 10 mg/kg d-AMPH, s.c.) that produced hyperthermia. Rats were sacrificed either 3 h or 1 day after dosing, and total RNA and protein was isolated from the meninges, arachnoid and pia membranes, and associated vasculature (MAV) that surround the forebrain. Vip, eNos, Drd1a, and Edn1 (genes regulating vascular tone) were increased by either EIH or AMPH to varying degrees in MAV, indicating that EIH and AMPH produce differential responses to enhance vasodilatation. AMPH, and EIH to a lesser extent, elicited a significant inflammatory response at 3 h as indicated by an increased MAV expression of cytokines Il1b, Il6, Ccl-2, Cxcl1, and Cxcl2. Also, genes related to heat shock/stress and disruption of vascular homeostasis such as Icam1 and Hsp72 were also observed. The increased expression of Ctgf and Timp1 and the decreased expression of Akt1, Anpep, and Mmp2 and Tek (genes involved in stimulating angiogenesis) from AMPH exposure suggest that angiogenesis was arrested or disrupted in MAV to a greater extent by AMPH compared to EIH. Alterations in vascular-related gene expression in the parietal cortex and striatum after AMPH were less in magnitude than in MAV, indicating less of a disruption of vascular homeostasis in these two regions. Changes in the levels of insulin-like growth factor binding proteins Igfbp1, 2, and 5 in MAV, compared to those in striatum and parietal cortex, imply an interaction between these regions to regulate the levels of insulin-like growth factor after AMPH damage. Thus, the vasculature and meninges surrounding the surface of the forebrain may be an important region in which AMPHs can disrupt vascular homeostasis.

Acute methamphetamine exposure inhibits cardiac contractile function

Methamphetamine, a commonly seen substance of abuse, has been reported to exert detrimental effect on bodily function including the cardiovascular system although its mechanism of action is poorly understood. This study was designed to examine the direct impact of methamphetamine on isolated whole heart and single cardiomyocyte contractile function. Murine hearts and isolated cardiomyocytes from adult FVB mice were exposed to various concentrations of methamphetamine for 30min prior to the assessment of mechanical function using a Langendroff apparatus and an IonOptix Myocam system, respectively. Cardiac contractile properties analyzed included maximal velocity of left ventricular pressure development and decline (+/-dP/dt), peak shortening amplitude (PS), maximal velocity of shortening/relengthening (+/-dLdt), time-to-PS (TPS), time-to-90% relengthening (TR(90)), resting and electrically stimulated increase of intracellular Ca(2+) as well as intracellular Ca(2+) decay. Our results revealed that acute methamphetamine exposure depressed +/-dP/dt, PS and rise of intracellular Ca(2+) without affecting +/-dLdt, TPS, TR(90), resting intracellular Ca(2+) and intracellular Ca(2+) decay. Furthermore, methamphetamine nullified the adrenergic agonist norepinephrine-elicited positive cardiomyocyte contractile response, including elevated PS, +/-dLdt and shortened TR(90) without affecting TPS. Western blot analysis showed unchanged expression of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a) and phospholamban, associated with upregulated Na(+)-Ca(2+) exchanger levels following acute methamphetamine exposure. In addition, methamphetamine promoted overt cardiomyocyte protein damage evaluated by carbonyl formation. Taken together, these results demonstrate direct cardiac depressant effect of methamphetamine in myocardium and isolated cardiomyocytes, possibly associated with protein damage and dampened adrenergic response.

Speeding stroke recovery? A systematic review of amphetamine after stroke

INTRODUCTION

The use of drugs to enhance recovery ("rehabilitation pharmacology") has been assessed. Amphetamine can improve outcome in experimental models of stroke, and several small clinical trials have assessed its use in stroke.

METHODS

Electronic searches were performed to identify randomised controlled trials of amphetamine in stroke (ischaemic or haemorrhagic). Outcomes included functional outcome (assessed as combined death or disability/dependency), safety (death) and haemodynamic measures. Data were analysed as dichotomous or continuous outcomes, using odds ratios (OR), weighted or standardised mean difference, (WMD or SMD) using random-effects models with 95% confidence intervals (95% CI); statistical heterogeneity was assessed.

RESULTS

Eleven completed trials (n=329) were identified. Treatment with amphetamine was associated with non-significant trends to increased death (OR 2.78 (95% CI, 0.75-10.23), n=329, 11 trials) and improved motor scores (WMD 3.28 (95% CI -0.48-7.04) n=257, 9 trials) but had no effect on the combined outcome of death and dependency (OR 1.15 (95% CI 0.65-2.06, n=206, 5 trials). Amphetamine increased systolic blood pressure (WMD 9.3 mmHg, 95% CI 3.3-15.3, n=106, 3 trials) and heart rate (WMD 7.6 beats per minute (bpm), 95% CI 1.8-13.4, n=106, 3 trials). Despite variations in treatment regimes, outcomes and follow-up duration there was no evidence of significant heterogeneity or publication bias.

CONCLUSION

No evidence exists at present to support the use of amphetamine after stroke. Despite a trend to improved motor function, doubts remain over safety and there are significant haemodynamic effects, the consequences of which are unknown.

BMP7 reduces synergistic injury induced by methamphetamine and ischemia in mouse brain

Previous studies have indicated that methamphetamine (MA) potentiates neurodegeneration induced by ischemia in brain. We, and others, have reported that bone morphogenetic protein 7 (BMP7) is protective against MA and ischemic brain injury. The purpose of this study is to examine whether BMP7 reduces synergistic injury induced by both MA and cerebral ischemia. Adult CD-1 mice were treated with MA (4x 10mg/kg, each dose 2h apart) or saline. Using the quantitative real time polymerase chain reaction, we found that MA suppressed the expression of BMP7 mRNA in the cerebral cortex 1 day after injection. Ischemic and reperfusional injuries were introduced by ligation of the right middle cerebral artery for 90min after MA injection. Animals were sacrificed for caspase-3/7 activity assay and tri-phenyl-tetrazolium chloride staining at 1h and 2 days after reperfusion, respectively. Cerebral infarction and caspase-3/7 activity were enhanced in the stroke animals pretreated with MA; both responses were attenuated by pretreatment with BMP7. In conclusion, our data suggest that MA facilitates cerebral infarction after ischemia possibly mediated, in part, through the suppression of BMP7.

Trends in methamphetamine use in young injection drug users in San Francisco from 1998 to 2004: the UFO Study

AIMS

To describe temporal trends in methamphetamine use among young injection drug users (IDU) in San Francisco.

DESIGN AND METHODS

Secondary analysis of cross-sectional baseline data collected for a longitudinal study of young IDU from 1998 to 2004. Participants were 1445 young IDU (<30 years old) who reported injection in the previous month, English-speaking, and recruited by street outreach methods. We examined trends for: lifetime (ever) and recent (30-day) methamphetamine use, including injected and non-injected, and by age group and sexual risk behaviour [men who have sex with men injecting drug users (MSM-IDU), male IDU (non-MSM) and female IDU].

RESULTS

In 1998, 1999, 2000, 2001, 2003 and 2004 we interviewed 237, 276, 431, 310, 147 and 44 participants, respectively. Overall, median age was 22 years [interquartile range (IQR) 20-25], 30.3% were women and median duration of injecting was 4.4 years (IQR 2-7). Prevalence of methamphetamine use was high, with 50.1% reporting recent injection, but overall there were no temporal increases in reported 'ever' injected use. Recent methamphetamine injection (past 30 days) increased significantly, and peaked at 60% in 2003. MSM-IDU had higher methamphetamine injection ever (92.3%) and recently (59.5%) compared to heterosexual male (non-MSM) IDU (81.6% and 47.3%, respectively) and to female IDU (78.4% and 46.1%, respectively).

CONCLUSIONS

Despite reports of ubiquitous increases in methamphetamine use, there were no significant increases in 6 years in ever injecting methamphetamine overall among young IDU. MSM-IDU who reported the highest methamphetamine use overall reported some increases in recent injected use. The methamphetamine 'epidemic' was probably under way among young IDU earlier than other populations.

Amphetamine increases blood pressure and heart rate but has no effect on motor recovery or cerebral haemodynamics in ischaemic stroke: a randomized controlled trial (ISRCTN 36285333)

Amphetamine enhances recovery after experimental ischaemia and has shown promise in small clinical trials when combined with motor or sensory stimulation. Amphetamine, a sympathomimetic, might have haemodynamic effects in stroke patients, although limited data have been published. Subjects were recruited 3-30 days post-ischaemic stroke into a phase II randomized (1:1), double-blind, placebo-controlled trial. Subjects received dexamphetamine (5 mg initially, then 10 mg for 10 subsequent doses with 3- or 4-day separations) or placebo in addition to inpatient physiotherapy. Recovery was assessed by motor scales (Fugl-Meyer (FM)), and functional scales (Barthel index (BI) and modified Rankin score (mRS)). Peripheral blood pressure (BP), central haemodynamics and middle cerebral artery blood flow velocity were assessed before, and 90 min after, the first two doses. Thirty-three subjects were recruited, aged 33-88 (mean 71) years, males 52%, 4-30 (median 15) days post stroke to inclusion. Sixteen patients were randomized to placebo and seventeen to amphetamine. Amphetamine did not improve motor function at 90 days; mean (s.d.) FM 37.6 (27.6) vs control 35.2 (27.8) (P=0.81). Functional outcome (BI, mRS) did not differ between treatment groups. Peripheral and central systolic BP, and heart rate (HR), were 11.2 mm Hg (P=0.03), 9.5 mm Hg (P=0.04) and 7 beats per minute (P=0.02) higher, respectively, with amphetamine, compared with control. A nonsignificant reduction in myocardial perfusion (BUI) was seen with amphetamine. Other cardiac and cerebral haemodynamics were unaffected. Amphetamine did not improve motor impairment or function after ischaemic stroke but did significantly increase BP and HR without altering cerebral haemodynamics.

Quantitative measurement of neurological deficit after mild (30 min) transient middle cerebral artery occlusion in rats

Although 30-min transient middle cerebral artery occlusion (30-min tMCAo) causes reproducible subcortical infarction in rats, it is difficult to evaluate the resulting neurological deficit using common behavioral tests such as the rota-rod test, adhesive-removal test, or narrow beam test. Establishment of a method of quantitative evaluation would help to develop a novel therapeutic approach to treat cerebral infarction. To solve this problem, we examined whether the neurological deficit could be detected by the Montoya staircase test or methamphetamine-induced rotation, which are commonly used in a Parkinson disease model induced by intrastriatal injection of 6-hydroxydopamine (6-OHDA). From 10 to 14 days after tMCAo, the Montoya staircase test showed significant clumsiness in forelimb tasks contralateral to the lesion side, whereas sham-operated rats showed no significant clumsiness in both forelimbs. The number of ipsilateral rotations induced by methamphetamine was also increased in tMCAo-rats at 21 days after tMCAo. Although Pearson's correlations coefficient showed that the results of these tests were correlated with the infarction volume, there was no significant correlation between the results of these two tests. These findings imply that the neurological deficit detected by both tests might reflect the severity of ischemic injury, but each test might evaluate different aspects of neurological deficit. Thus, the Montoya staircase test and methamphetamine-induced rotation are useful to evaluate neurological deficit in the chronic stage of subcortical infarction induced by 30-min tMCAo.

Histogranin reduced brain injury after transient focal ischemia in rats

Excitatory amino acids (EAAs) play an important role during ischemic brain injury. In this study we examined the protective effect of histogranin (HN), an endogenous peptide that antagonizes excitatory amino acids-mediated activity noncompetitively, in an animal model of cerebral ischemia. Adult rats were anesthetized with chloral hydrate. Histogranin was given intracerebroventricularly before a 60-min middle cerebral artery occlusion (MCAo). Animals were examined for their locomotor activity 2 days after MCAo. Histogranin significantly increased locomotor activity in the stroke rats. Histogranin pretreatment reduced the volume of cerebral infarction and the caspase-3 immunoreactivity in the stroke animals. Taken together, our data suggest that histogranin is protective against ischemic brain injury. The protective effect may involve anti-apoptotic mechanisms.

Exogenous acid fibroblast growth factor inhibits ischemia-reperfusion-induced damage in intestinal epithelium via regulating P53 and P21WAF-1 expression

AIM

To detect the effect of acid fibroblast growth factor (aFGF) on P53 and P21WAF-1 expression in rat intestine after ischemia-reperfusion (I-R) injury in order to explore the protective mechanisms of aFGF.

METHODS

Male rats were randomly divided into four groups, namely intestinal ischemia-reperfusion group (R), aFGF treatment group (A), intestinal ischemia group (I), and sham-operated control group (C). In group I, the animals were killed after 45 min of superior mesenteric artery (SMA) occlusion. In groups R and A, the rats sustained for 45 min of SMA occlusion and were treated with normal saline (0.15 mL) and aFGF (20 mug/kg, 0.15 mL), then sustained at various times for up to 48 h after reperfusion. In group C, SMA was separated, but without occlusion. Apoptosis in intestinal villi was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling technique (TUNEL). Intestinal tissue samples were taken not only for RT-PCR to detect P53 and P21WAF-1 gene expression, but also for immunohistochemical analysis to detect P53 and P21WAF-1 protein expression and distribution.

RESULTS

In histopathological study, ameliorated intestinal structures were observed at 2, 6, and 12 h after reperfusion in A group compared to R group. The apoptotic rates were (41.17+/-3.49)%, (42.83+/-5.23)%, and (53.33+/-6.92)% at 2, 6, and 12 h after reperfusion, respectively in A group, which were apparently lower than those in R group at their matched time points (50.67+/-6.95)%, (54.17+/-7.86)%, and (64.33+/-6.47)%, respectively, (P<0.05)). The protein contents of P53 and P21WAF-1 were both significantly decreased in A group compared to R group (P<0.05) at 2-12 h after reperfusion, while the mRNA levels of P53 and P21WAF-1 in A group were obviously lower than those in R group at 6-12 h after reperfusion (P<0.05).

CONCLUSION

P53 and P21WAF-1 protein accumulations are associated with intestinal barrier injury induced by I-R insult, while intravenous aFGF can alleviate apoptosis of rat intestinal cells by inhibiting P53 and P21WAF-1 protein expression.

HIV-associated medical, behavioral, and psychiatric characteristics of treatment-seeking, methamphetamine-dependent men who have sex with men

This paper examines medical and psychiatric symptoms and disorders associated with reported HIV serostatus among methamphetamine-dependent, treatment-seeking men who have sex with men (MSM) in Los Angeles. Baseline data from a NIDA-funded, randomized clinical trial of behavioral drug abuse therapies included medical examinations and behavioral interviews of the 162 randomized participants. Variables identified as significantly associated with HIV infection were entered into a multivariate, hierarchical logistic regression analysis to optimally predict HIV serostatus. The disturbingly high 61% of the sample with reported HIV-seropositive status represents 3-4 times the prevalence for all MSM in Los Angeles County. HIV infection status strongly associated with prior treatment for methamphetamine dependence; unprotected receptive anal intercourse; history of sexually transmitted infections; and health insurance status. Findings demonstrate the powerful connection between methamphetamine dependence and HIV infection, and strongly suggest a need for development of interventions that function as both substance abuse treatment and HIV prevention for this population.

Increased white matter hyperintensities in male methamphetamine abusers

BACKGROUND

The current study was conducted to compare the prevalence, severity, and location of white matter signal hyperintensities (WMH) on brain magnetic resonance (MR) imaging in methamphetamine (MA) abusers.

METHODS

Thirty-three MA abusers and 32 age- and gender-matched healthy comparison subjects were studied. Axial T-2 weighted images and fluid attenuated inversion recovery axial images were obtained using 3.0 T MR scanner. The severity of WMH was assessed separately for deep and periventricular WMH. Ordinal logistic regression models were used to assess the odds ratio for WMH.

RESULTS

MA abusers had greater severity of WMH than the healthy comparison subjects (odds ratio: 7.06, 8.46, and 4.56 for all, deep, and periventricular WMH, respectively). Severity of deep WMH correlated with total cumulative dose of MA (p = 0.027). Male MA abusers had greater severity of WMH than female MA abusers (odds ratio = 10.00). While male MA abusers had greater severity of WMH than male comparison subjects (odds ratio = 18.86), there was no significant difference in WMH severity between female MA abusers and female comparison subjects.

CONCLUSIONS

The current study reports increased WMH in MA abusers, which may be related to MA-induced cerebral perfusion deficits. In addition, female MA abusers had less severe WMH than male MA abusers, possibly due to estrogen's protective effect against ischemic or neurotoxic effects of MA.

Acid fibroblast growth factor reduces rat intestinal mucosal damage caused by ischemia-reperfusion insult

AIM: To detect the effects of acid fibroblast growth factor (aFGF) on apoptosis and proliferation of intestinal epithelial cells in differentiation or proliferation status to explore the protective mechanisms of aFGF.

METHODS: Wistar rats were randomly divided into sham-operated control group (C, n = 6), intestinal ischemia group (I, n = 6), aFGF treatment group (A, n = 48) and intestinal ischemia-reperfusion group (R, n = 48). Apoptosis of intestinal mucosal cells was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) technique. Proliferating cell nuclear antigen (PCNA) protein expression and distribution were detected with immunohistochemical method. Plasma levels of D-lactate were determined with modified Brandts method.

RESULTS: In A group, administration of exogenous aFGF could improve intestinal histological structure and decrease plasma D-lactate levels at 2-12 h after the reperfusion compared with R group. The apoptotic rates and PCNA protein expressions were not increased until 2 h after reperfusion and were maximal at 12 h. After reperfusion for 2-12 h, the apoptotic rates were gradually augmented along the length of jejunal crypt-villus units. Administration of aFGF could significantly reduce the apoptotic response at 2-12 h after reperfusion (P<0.05). Apoptosis rates in villus and crypt epithelial cells in A group at 12 h after reperfusion were (62.5±5.5)% and (73.2±18.6)% of those in R group, respectively. Treatment of aFGF could apparently induce protein expression of PCNA in intestinal mucosal cells of A group compared with R group during 2-12 h after reperfusion (P<0.05). There were approximately 1.3- and 1.5-times increments of PCNA expression levels in villus and crypt cells in A group at 12 h after reperfusion compared with R group, respectively.

CONCLUSION: Intestinal I/R insult could lead to histological structure change and apoptotic rate increment. The protective effects of aFGF against ischemia/reperfusion in rat intestinal mucosa might be partially due to its ability to inhibit ischemia/reperfusion-induced apoptosis and to promote cell proliferation of crypt cells and villus epithelial cells.

Intravenous acid fibroblast growth factor protects intestinal mucosal cells against ischemia-reperfusion injury via regulating Bcl-2/Bax expression

AIM: To detect the effect of acid fibroblast growth factor (aFGF) on apoptosis and gene expression of bax and bcl-2 gene in rat intestine after ischemia/reperfusion (I/R) injury, and to explore the protective mechanisms of aFGF.

METHODS: One hundred and eight Wistar rats were randomly divided into sham-operated control group (C) (n = 6), intestinal ischemia group (I) (n = 6), aFGF treatment group (A) (n = 48) and intestinal ischemia-reperfusion group (R) (n = 48). In group I, the animals were killed after 45 min of superior mesenteric artery (SMA) occlusion, while in groups R and A, the rats sustained 45 min of SMA occlusion and were then treated with normal saline and aFGF, respectively, sustained 15 min, 30 min, 1, 2, 6, 12, 24, or 48 h of reperfusion, respectively. In group C, SMA was separated, but without occlusion. Apoptosis in intestinal villus was determined with terminal deoxynucleotidyl transferase mediated dUTP-biotin nick-end labeling technique (TUNEL). Intestinal tissue samples were taken not only for detection of bax and bcl-2 gene expression by RT-PCR, but also for detection of bax and bcl-2 protein expression and distribution by immunohistochemical analysis.

RESULTS: The rat survival rates in aFGF treated group were higher than group R (P<0.05) and the improvement of intestinal histological structures was observed at 2, 6, and 12 h after the reperfusion in group A compared with group R. The apoptotic rates were (41.17±3.49)%, (42.83±5.23)% and (53.33±6.92)% at 2, 6 and 12 h after reperfusion, respectively in group A, apparently less than those of group R at matched time points (50.67±6.95, 54.17±7.86, 64.33±6.47, respectively) (P<0.05). The bax gene transcription and translation were significantly decreased in group A vs group R, while mRNA and protein contents of Bcl-2 in group A were obviously higher than those in group R during 2-12 h period after reperfusion.

CONCLUSION: The changes in histological structure and the increment of apoptotic rate indicated that the intestinal barrier was damaged after intestinal I/R injury, whilst intravenous aFGF could alleviate apoptosis induced by ischemia and reperfusion in rat intestinal tissues, in which genes of bax and bcl-2 might play important roles.

Dietary supplementation with blueberries, spinach, or spirulina reduces ischemic brain damage

Free radicals are involved in neurodegenerative disorders, such as ischemia and aging. We have previously demonstrated that treatment with diets enriched with blueberry, spinach, or spirulina have been shown to reduce neurodegenerative changes in aged animals. The purpose of this study was to determine if these diets have neuroprotective effects in focal ischemic brain. Adult male Sprague-Dawley rats were fed with equal amounts of diets (blueberry, spinach, and spirulina) or with control diet. After 4 weeks of feeding, all animals were anesthetized with chloral hydrate. The right middle cerebral artery was ligated with a 10-O suture for 60 min. The ligature was later removed to allow reperfusional injury. Animals were sacrificed and brains were removed for caspase-3 enzymatic assays and triphenyltetrazolium chloride staining at 8 and 48 h after the onset of reperfusion. A subgroup of animals was used for locomotor behavior and biochemical assays. We found that animals which received blueberry, spinach, or spirulina enriched diets had a significant reduction in the volume of infarction in the cerebral cortex and an increase in post-stroke locomotor activity. There was no difference in blood biochemistry, blood CO2, and electrolyte levels among all groups, suggesting that the protection was not indirectly mediated through the changes in physiological functions. Animals treated with blueberry, spinach, or spirulina had significantly lower caspase-3 activity in the ischemic hemisphere. In conclusion, our data suggest that chronic treatment with blueberry, spinach, or spirulina reduces ischemia/reperfusion-induced apoptosis and cerebral infarction.

Bone marrow grafts restore cerebral blood flow and blood brain barrier in stroke rats

We monitored alterations in cerebral blood flow (CBF) and blood-brain barrier (BBB) permeability following middle cerebral artery occlusion (MCAo) and intrastriatal transplantation of mouse bone marrow stromal cells (BMSCs) or saline infusion in adult Sprague-Dawley rats. Laser Doppler and Evans Blue assay revealed that BMSC grafts dose-dependently restored CBF and BBB to near normal levels at a much earlier period (Days 4-5 post-MCAo) in transplanted stroke animals compared to stroke animals that received saline infusion (Days 11-14 post-MCAo). Xenografted BMSCs survived in the absence of immunosuppression, and elevated levels of transforming growth factor-beta superfamily of neurotrophic factors were detected in transplanted stroke animals. These data suggest that early restoration of CBF and BBB following transplantation of BMSCs could mediate the reported functional outcomes in stroke animals.

Intracerebral xenografts of mouse bone marrow cells in adult rats facilitate restoration of cerebral blood flow and blood–brain barrier

We examined in the present study alterations in cerebral blood flow (CBF) and blood-brain barrier (BBB) permeability following intrastriatal transplantation of mouse bone marrow stromal cells (BMSCs) or saline infusion in adult Sprague-Dawley rats. Laser Doppler revealed that transplanted animals exhibited near normal cerebral blood flow (CBF, 150 perfusion units) at a much earlier period post-transplantation (day 4) compared to animals that received saline infusion (day 12) (p's<0.05). Similarly, Evans Blue assay demonstrated that transplanted animals exhibited near complete BBB reconstitution at day 5 post-transplantation, whereas animals that received saline infusion continued to display a compromised BBB up to 11 days post-transplantation. Transplanted animals displayed a cell dose-dependent CBF and BBB restoration. Enzyme-linked immunosorbent assay (ELISA) of transplanted BMSCs revealed elevated levels of transforming growth factor-beta superfamily of neurotrophic factors. Moreover, despite the absence of immunosuppression in this cross-species transplantation, at least in the acute phase (12 days post-transplantation), surviving xenografts were detected during periods of restored CBF and BBB permeability. These observations suggest that restoration of CBF and BBB permeability accompanies the reported functional outcomes associated with intracerebral transplantation of BMSCs.

Diadenosine tetraphosphate protects against injuries induced by ischemia and 6-hydroxydopamine in rat brain

Diadenosine tetraphosphate (AP4A), an endogenous diadenosine polyphosphate, reduces ischemic injury in the heart. In this study, we report the potent and protective effects of AP4A in rodent models of stroke and Parkinson's disease. AP4A, given intracerebroventricularly before middle cerebral artery (MCA) ligation, reduced cerebral infarction size and enhanced locomotor activity in adult rats. The intravenous administration of AP4A also induced protection when given early after MCA ligation. AP4A suppressed terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) induced by hypoxia/reperfusion in primary cortical cultures, and reduced both ischemia-induced translocation of mitochondrial cytochrome c and the increase in cytoplasmic caspase-3 activity in vivo. The purinergic P2/P4 antagonist di-inosine pentaphosphate or P1-receptor antagonist sulfonylphenyl theophylline, but not the P2-receptor antagonist suramin, antagonized the effect of AP4A, suggesting that the observed protection is mediated through an anti-apoptotic mechanism and the activation of P1- and P4-purinergic receptors. AP4A also afforded protection from toxicity induced by unilateral medial forebrain bundle injection of 6-hydroxydopamine (6-OHDA). One month after lesioning, vehicle-treated rats exhibited amphetamine-induced rotation. Minimal tyrosine hydroxylase immunoreactivity was detected in the lesioned nigra or striatum. No KCl-induced dopamine release was found in the lesioned striatum. All of these indices of dopaminergic degeneration were attenuated by pretreatment with AP4A. In addition, AP4A reduced TUNEL in the lesioned nigra 2 d after 6-OHDA administration. Collectively, our data suggest that AP4A is protective against neuronal injuries induced by ischemia or 6-OHDA through the inhibition of apoptosis. We propose that AP4A may be a potentially useful target molecule in the therapy of stroke and Parkinson's disease.

HSV amplicon delivery of glial cell line-derived neurotrophic factor is neuroprotective against ischemic injury

Direct intracerebral administration of glial cell line-derived neurotrophic factor (GDNF) is neuroprotective against ischemia-induced cerebral injury. Utilizing viral vectors to deliver and express therapeutic genes presents an opportunity to produce GDNF within localized regions of an evolving infarct. We investigated whether a herpes simplex virus (HSV) amplicon-based vector encoding GDNF (HSVgdnf) would protect neurons against ischemic injury. In primary cortical cultures HSVgdnf reduced oxidant-induced injury compared to the control vector HSVlac. To test protective effects in vivo, HSVgdnf or HSVlac was injected into the cerebral cortex 4 days prior to, or 3 days, after a 60-min unilateral occlusion of the middle cerebral artery. Control stroke animals developed bradykinesia and motor asymmetry; pretreatment with HSVgdnf significantly reduced such motor deficits. Animals receiving HSVlac or HSVgdnf after the ischemic insult did not exhibit any behavioral improvement. Histological analyses performed 1 month after stroke revealed a reduction in ischemic tissue loss in rats pretreated with HSVgdnf. Similarly, these animals exhibited less immunostaining for glial fibrillary acidic protein and the apoptotic marker caspase-3. Taken together, our data indicate that HSVgdnf pretreatment provides protection against cerebral ischemia and supports the utilization of the HSV amplicon for therapeutic delivery of trophic factors to the CNS.

Dexamphetamine treatment in stroke

Reducing disability and dependency after a stroke is an important clinical objective. We examine what is known about the use of dexamphetamine in patients recovering from an acute stroke, and consider whether further clinical studies should be undertaken. Dexamphetamine has repeatedly been shown to enhance recovery after experimental brain injury in animals, the best effects being seen when dexamphetamine is combined with lesion-specific motor training or sensory stimulation. Postulated mechanisms for these beneficial effects in animals are in keeping with contemporary theories of neurophysiological rehabilitation in man. There have been few clinical studies of dexamphetamine during rehabilitation after an acute stroke. Four controlled trials demonstrated a tendency to an improved outcome when dexamphetamine was paired with therapy and administered 3-30 days after an ischaemic stroke. However, clinical studies to date have been small, included only highly selected patients, and have not addressed possible confounding effects of the drug on mood and untreated depression. Dexamphetamine has previously been used under supervision in medically ill patients and appears to be safe and well-tolerated. There is a need for well-designed studies to assess further the safety and efficacy of dexamphetamine in rehabilitation after stroke.

Chronic [D-Ala2, D-Leu5]enkephalin treatment increases the nerve growth factor in adult mouse brain

The delta opioid peptide [D-Ala(2), D-Leu(5)]enkephalin (DADLE) has been shown to enhance the survival of dopaminergic neurons. Here, we found that chronic treatment with DADLE caused a significant increase in nerve growth factor (NGF) in the hippocampus and the midbrain of adult albino Swiss (CD-1) mice, but not in the striatum or frontal cortex. Glia-derived neurotrophic factor (GDNF) was not significantly affected. Thus, the neuroprotective action of DADLE may be mediated in part by NGF.

Effects of chronic methamphetamine exposure on heart function in uninfected and retrovirus-infected mice

Methamphetamine (MA) increases catecholamine levels, which have detrimental effects on heart function through vasoconstriction, myocardial hypertrophy, and fibrosis. Murine retrovirus infection induces dilated cardiomyopathy (DCM). The present study investigated the cardiovascular effects of chronic MA treatment on uninfected and retrovirus-infected mice. C57BL/6 mice were studied after 12 weeks treatment. The four study groups were (group I) uninfected, MA placebo; (group II) infected, MA placebo; (group III) uninfected, MA treatment; and (group IV) infected and MA treatment. MA injections were given i.p. once a day for 5 days/week with a increasing dose from 15 mg/kg to 40 mg/kg. Left ventricular mechanics were measured in situ a using Millar conductance catheter system for pressure-volume loop analysis. Cardiac pathology was determined with histological analysis. In the uninfected mice, the load independent contractile parameters, pre-load recruitable stroke work (PRSW) and dP/dt(max) vs. Ved, significantly decreased by 32% and 35% in MA treated mice when compared to the saline injected mice. In retrovirus-infected mice, although there were no significant difference in Ees, PRSW, and dP/dt(max) vs. Ved due to MA treatment, they were increased 45%, 15% and 42% respectively when compared to saline treated mice. No further lowered heart function during murine AIDS may be due to the counteraction of the retroviral DCM and the MA induced myocardial fibrosis and hypertrophy (thickening of the ventricular walls). This is supported by increases in the End-diastolic volume (Ved, 38%) and End-systolic volume (Ves, 84%) in the retrovirus-infected saline injected mice, the decreases of 33% and 17% in the uninfected MA-treated mice, but no significant changes in the retrovirus-infected MA treated mice when compared to uninfected saline injected mice. These data suggest that MA induced myocardial cellular changes compensate for retrovirus induced DCM.