Amino acid transmitters in patients with headache during the acute phase of cerebrovascular ischemic disease

New Perspectives in Neuroprotection for Ischemic Stroke

The constant failure of new neuroprotective therapies for ischemic stroke has partially halted the search for new therapies in recent years, mainly because of the high investment risk required to develop a new treatment for a complex pathology, such as stroke, with a narrow intervention window and associated comorbidities. However, owing to recent progress in understanding the stroke pathophysiology, improvement in patient care in stroke units, development of new imaging techniques, search for new biomarkers for early diagnosis, and increasingly widespread use of mechanical recanalization therapies, new opportunities have opened for the study of neuroprotection. This review summarizes the main protective agents currently in use, some of which are already in the clinical evaluation phase. It also includes an analysis of how recanalization therapies, new imaging techniques, and biomarkers have improved their efficacy.

Bilateral paramedian pontine infarcts: a rare cause of bilateral horizontal gaze palsy

A 73-year-old man presented to accident and emergency with headache and diplopia. Examination of the eye movements revealed a bilateral complete horizontal gaze palsy. On admission, a CT scan of the brain was performed, which was unremarkable. An MRI of the brain was then performed, which confirmed tiny acute infarcts involving the pons and the right cerebellum. This man was promptly treated with aspirin 300 mg one time per day, as per the stroke pathway. Further diagnostic workup later revealed atrial flutter. This man was therefore commenced on apixaban. The differential diagnoses for bilateral gaze palsy include the following: multiple sclerosis, infarction, haemorrhage and space occupying lesion. Bilateral gaze palsy is often associated with other neurological symptoms.

Exploring the neuroprotective effects of ginkgolides injection in a rodent model of cerebral ischemia-reperfusion injury by GC-MS based metabolomic profiling

Cerebral ischemia-reperfusion (I/R) injury usually contributes to mortality and disability after ischemic stroke. Ginkgolides injection (GIn), a standard preparation composed of ginkgo diterpene lactones extract, is clinically used for neuroprotective treatment on reconvalescents of cerebral infarction. However, the understanding about its therapeutic mechanism is still lacking. In this study, a gas chromatography-mass spectrometry (GC-MS) based metabolomic approach coupled with multivariate data analysis (MVDA) was applied to explore the neuroprotective effects of GIn in a rodent model of focal ischemic stroke induced by transient middle cerebral artery occlusion (tMCAO). Metabolomic profiling revealed a series of metabolic perturbations that underlie the cerebral I/R pathological events. GIn can reverse the I/R induced brain metabolic deviations by modulating multiple metabolic pathways, such as glycolysis, Krebs cycle, pentose phosphate pathway (PPP), γ-aminobutyrate (GABA) shunt and lipid metabolism. Moreover, the main bioactive components of GIn were distributed to brain tissue much more easily in tMCAO rats than in normal rats after an intravenous administration, suggesting that the increased cerebral exposure to ginkgolides in I/R pathological condition potentially facilitated the neuroprotective effects of GIn by directly targeting at brain. The present study provided valuable information for our understanding about metabolic changes of cerebral I/R injury and clinical application of GIn.

Post-IV thrombolytic headache and hemorrhagic transformation risk in acute ischemic stroke

Background:

Headache during or soon after administration of IV tissue plasminogen activator (tPA) in patients with acute ischemic stroke (AIS) is a concern for hemorrhagic transformation (HT). However, no data are available regarding the incidence of HT in these patients or the prognostic indication of these headaches. We examine the importance of tPA-associated headaches among AIS patients in terms of HT rates and clinical outcomes.

Methods:

AIS patients treated with IV tPA at a comprehensive stroke center between January 2007 and November 2012 were retrospectively reviewed for documented tPA-associated headache in the first 24 hours post-tPA. We compared the headache and nonheadache groups for differences in various clinical and radiologic outcomes.

Results:

Of the 193 patients, 63 (32.6%) had tPA-associated headache. Headache patients (HP) were younger than nonheadache patients (NHP) (mean ± SD, 59.5 ± 17.4 years vs 69.9 ± 15.5 years, p < 0.0001), and 53% of HP were men, compared to 49.2% of NHP (p = 0.537). Comorbid conditions did not differ between the 2 groups. There were no statistical differences between HP and NHP in admission NIH Stroke Scale (NIHSS) score (11.2 ± 5.7 vs 11.5 ± 5.5, p = 0.646), NIHSS score at 24 hours (6.5 ± 5.7 vs 7.4 ± 6.9, p = 0.466), NIHSS score at discharge (6.7 ± 10.1 vs 8.1 ± 11.6, p = 0.448), HT (12.7% vs 18.4%, p = 0.3), cervical artery dissection (4.7% vs 5.38%, p = 0.764), length of hospitalization (6.29 ± 5 days vs 6.35 ± 4.7 days, p = 0.935), and disposition.

Conclusion:

tPA-associated headache does not predict increased risk of HT and has no other prognostic importance in patients with AIS. Prospective studies with a larger cohort may be needed to further explore this relationship.

A novel mechanism of neuroprotection: Blood glutamate grabber

Glutamate excitotoxicity is a primary contributor of ischemic neuronal death and other cellular components of the neurovascular unit. Several strategies have been developed against glutamate excitotoxicity, however none of them have not shown positive results in the clinical practice so far. Nowadays, the concept of blood/brain glutamate grabbing or scavenging is well recognized as a novel and attractive protective strategy to reduce the excitotoxic effect of excess extracellular glutamate that accumulates in the brain following an ischemic stroke. The main advantage of this novel therapeutic strategy is that it occurs in the blood circulation and therefore does not affect the normal brain neurophysiology, as it has been described for other drug treatments used against glutamate excitotoxicity. In this work we report all experimental data from the beginning of our studies, focused on stroke pathology, and we describe new findings about the potential application of this therapy. Future clinical trials will allow to know the real efficacy of this novel therapeutic strategy in stroke patients.

A glutamate-dependent redox system in blood cells is integral for phagocytosis in Drosophila melanogaster

Glutamate transport is highly regulated as glutamate directly acts as a neurotransmitter and indirectly regulates the synthesis of antioxidants. Although glutamate deregulation has been repeatedly linked to serious human diseases such as HIV infection and Alzheimer's, glutamate's role in the immune system is still poorly understood. We find that a putative glutamate transporter in Drosophila melanogaster, polyphemus (polyph), plays an integral part in the fly's immune response. Flies with a disrupted polyph gene exhibit decreased phagocytosis of microbial-derived bioparticles. When infected with S. aureus, polyph flies show an increase in both susceptibility and bacterial growth. Additionally, the expression of two known glutamate transporters, genderblind and excitatory amino acid transporter 1, in blood cells affects the flies' ability to phagocytose and survive after an infection. Consistent with previous data showing a regulatory role for glutamate transport in the synthesis of the major antioxidant glutathione, polyph flies produce more reactive oxygen species (ROS) as compared to wild-type flies when exposed to S. aureus. In conclusion, we demonstrate that a polyph-dependent redox system in blood cells is necessary to maintain the cells' immune-related functions. Furthermore, our model provides insight into how deregulation of glutamate transport may play a role in disease.

Glutamate oxaloacetate transaminase: a new key in the dysregulation of glutamate in migraine patients

OBJECTIVE

Based on the capacity of the blood-resident enzyme glutamate oxaloacetate transaminase (GOT) to metabolize blood glutamate, our aim was to study the association of GOT activity with serum glutamate levels and clinical parameters in patients with migraine.

METHODS

This case-control study included 45 episodic migraine patients (IHS 2004 criteria) and 16 control subjects. We analyzed glutamate and GOT activity in peripheral blood samples obtained during interictal periods and migraine attacks ( N  = 15). Frequency, severity, and duration of attacks and time of evolution were also recorded.

RESULTS

Migraine patients showed lower GOT activity than controls (15.2 ± 2.9 vs. 18.7 ± 3.8 U/l) and higher levels of glutamate (153.7 ± 68.6 vs. 121.5 ± 59.2 μM) (all P  < 0.05). A negative correlation was found between GOT activity and glutamate levels ( R  = -0.493; P  < 0.0001) in interictal periods; however, this negative correlation was lost during attacks ( R  = -0.026; P  = 0.925). During attacks, we found a positive correlation between the time elapsed from attack onset and glutamate levels ( R  = 0.738; P  < 0.0001), but not for GOT activity ( R  = -0.075; P  = 0.809).

CONCLUSIONS

Migraine patients showed reduced GOT activity and increased levels of blood glutamate levels as compared to control subjects. Furthermore, a negative correlation was found between GOT activity and glutamate levels in interictal periods.

Haemorrhagic pure motor stroke

To describe the clinical characteristics of haemorrhagic pure motor stroke (PMS). Twelve patients with haemorrhagic PMS were identified. Haemorrhagic PMS accounted for 3.2% of all cases of pure motor hemiparesis (n = 380) and 3.3% of intracerebral haemorrhage (n = 364) entered in the database. When compared with PMS of ischaemic origin, patients with haemorrhagic PMS were more likely to be younger (62.2 vs. 75.2 years, P = 0.003) and to have headache (33% vs. 6.3%, P =0.007) and thalamus involvement (25% vs. 2.4%, P = 0.005). Limb weakness (100% vs. 74.1%; P = 0.03), involvement of the internal capsule (50% vs. 17.3%, P = 0.012) and symptom free at discharge (25% vs. 3.7%, P = 0.012) were significantly more frequent in patients with haemorrhagic PMS than in the remaining cases of haemorrhagic stroke, whereas nausea and vomiting (0% vs. 25.9%, P = 0.03), altered consciousness (0% vs. 42.9%, P = 0.001), sensory symptoms (8.3% vs. 46.9%, P =0.007) and ventricular haemorrhage (0% vs. 26.1%, P = 0.028) were significantly less frequent. Haemorrhagic PMS is a very infrequent stroke subtype. Headache at stroke onset may be useful sign for distinguishing haemorrhagic PMS from other causes of lacunar stroke. There are important differences between haemorrhagic PMS and the remaining intracerebral haemorrhages.

Changes in amino acids and nitric oxide concentration in cerebrospinal fluid during labor pain

This study analyzes the relationship between amino acids and pain perception during active labor. Cerebrospinal fluid (CSF) levels of the excitatory amino acids (EAAs)-glutamate, aspartate and their amide forms, inhibitory amino acids (IAAs)-glycine, gamma-amino butyric acid (GABA) and taurine and nitric oxide (NO) related compounds-arginine and citrulline (by-product of NO synthesis) were compared between pregnant women at term pregnancy with labor pain (n = 38) and without labor pain (Caesarian section; n = 30). The levels of aspartate, glycine, GABA and citrulline were significantly higher; whilst taurine was significantly lower in the labor pain group. These findings suggest that aspartate and NO are associated with labor pain. An inhibitory role for the IAA taurine and a pronociceptive role for glycine in labor pain are proposed.

Clinical Implications of Headache in Lacunar Stroke: Relevance of Site of Infarct

OBJECTIVE

To assess whether the infarction topography influenced upon the incidence of headache and the likelihood of neurological recovery in lacunar infarction.

BACKGROUND

The relationship between topography of infarction and the incidence of headache as well as the influence of headache on neurological outcome in patients with lacunar stroke are still unclear.

METHODS

In a cohort of 387 patients with neuroimaging-proven acute lacunar infarction collected from a prospective hospital-based stroke registry over a 12-year period, 43 patients (11.1%) presented with headache within a 72-hour interval of stroke onset.

RESULTS

Headache was more common in deep brain gray matter or brainstem lacunar infarction than in supratentorial white matter lacunar infarction (14.9% vs 8%, P < .033), but lacunar infarctions in the supratentorial white matter had less frequently absence of limitation at discharge (15.1% vs 25.1%, P < .013). In deep brain gray matter or brainstem lacunar infarction, early neurological recovery decreased from 26.2% to 19.2% when headache was present at stroke onset. In the multivariate analysis, dysarthria-clumsy hand and absence of headache in deep brain gray matter or brainstem lacunar infarction were independent predictors of favorable outcome.

CONCLUSIONS

In patients with lacunar infarction, headache at stroke onset was more common in deep brain gray matter or brainstem topographies than in supratentorial white matter lesions. In deep brain gray matter or brainstem lacunar infarctions, early neurological recovery was less likely when headache was present.

Human platelets express the synaptic markers VGLUT1 and 2 and release glutamate following aggregation

Vesicular glutamate transporters (VGLUTs) are involved in storing glutamate for secretion at the level of glutamatergic axon terminals, and for this reason they have been extensively used as markers to identify glutamate-releasing cells. Platelets have been considered as a suitable model for studying glutamatergic dysfunction because they perform glutamate uptake and express both external transporters, and NMDA-like receptors. Here, we show that platelets express the pre-synaptic markers VGLUT1 and VGLUT2 and release glutamate following aggregation, implying a possible contributory role in the pathophysiology of stroke, migraine, and other excitotoxic disorders.

Stroke-Related Headache: A Clinical Study in Lacunar Infarction

OBJECTIVE

To describe the characteristics of headache related to lacunar stroke based on data collected from a prospective hospital-based stroke registry over a 12-year period. Demographics, clinical variables, and prognostic features of lacunar stroke in patients with and without headache are compared.

BACKGROUND

Stroke-related headache has been largely investigated, but there is little clinical data on headache in individualized stroke subtypes.

METHODS

The cohort of 484 patients with lacunar infarction was selected. Forty-five (9.3%) presented headache within a 72-hour interval of stroke onset. Predictors of lacunar infarction with headache were assessed by logistic regression analysis.

RESULTS

The intensity of headache was mild in severity and poorly localized (diffuse or bilateral headache). Tension-type headache was present in 36 patients (80%) and 9 patients (20%) presented nausea or vomiting while experiencing mild pulsating pain. The frequency of headache was 17% in patients with atypical lacunar syndrome, 12% in dysarthria-clumsy hand, 11.5% in pure sensory stroke, 9.4% in sensorimotor stroke, and 7.1% in pure motor hemiparesis. When patients with lacunar infarction with and without headache were compared, female sex, diabetes mellitus, nausea and vomiting, and mesencephalic topography were significantly more frequent and dysarthria and frequency of symptom free at discharge were less frequent in the headache group. In the multivariate analysis, mesencephalic topography (odds ratio [OR] 16.62), nausea and vomiting (OR 13.27), sex female (OR 2.29), diabetes mellitus (OR 1.96), and age (OR 0.95) were predictors of lacunar infarction with headache.

CONCLUSIONS

Headache at the onset of a lacunar infarction is uncommon. Mesencephalic topography, nausea and vomiting, female sex, diabetes, and age were independent variables significantly associated with lacunar infarction with headache. These findings contribute to knowledge of stroke-related headache in patients with lacunes.

Headache in Cerebral Hemorrhage Is Associated With Inflammatory Markers and Higher Residual Cavity

BACKGROUND AND PURPOSE

The mechanisms responsible for headache in patients with intracerebral hemorrhage (ICH) are not completely understood. The present study was undertaken to analyze the headache-associated factors, the possible related biochemical mechanisms, and the headache potential predictors of outcome in spontaneous ICH.

METHODS

We prospectively studied 189 patients from a large cohort of 266 consecutive patients with supratentorial ICH admitted within the first 12 hours of symptoms onset. The presence of headache at stroke onset was evaluated in these patients. The volumes of the initial ICH, peripheral edema at 48 hours, and the residual cavity at 3 months were measured on CT scan. Glutamate, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha levels were measured in blood samples obtained on admission. The Canadian Stroke Scale (CSS) and the modified Rankin Scale were used to evaluate stroke severity and neurological outcome, respectively.

RESULTS

Headache at onset of stroke was observed in 65 patients (34.4%). Patients who experienced headache had a significantly higher frequency of history of infection (P= .009) or inflammation (P= .045), as well as higher body temperature (P= .021), leukocyte count (P= .038), ESR (P= .011), and mass effect (P= .017) on admission. Plasma concentrations of IL-6 and TNF-alpha were significantly higher in patients with headache than in those without. Headache was an independent predictor of the residual cavity volume in patients with spontaneous ICH (odds ratio 6.49; 95% CI 2.51 to 16.78; P= .0001).

CONCLUSIONS

Headache at ICH onset is associated with clinical and biochemical markers of inflammation and is an independent predictor of higher residual cavity volume after spontaneous ICH.

The risk of stroke in patients with migraine and implications for migraine management

Assessing the risk of stroke in persons with migraine is complicated by the intricate relationship between these two conditions. Both migraine and stroke are common and co-morbidity may, in some cases, be coincidental. Given the overlap of clinical symptoms in stroke and migraine, each condition may also mimic the other. Numerous studies have, however, shown that migraine is an independent risk factor for stroke both during, and remote from, the migraine attack. Women of childbearing age and those with aura are at greatest risk of migraine-related stroke. Additional risk of stroke in migraineurs occurs in those using oral contraceptive pills and who smoke cigarettes. Elevated blood pressure, an important stroke risk factor, is less common in migraineurs. Acquired antiphospholipid antibodies, not clearly a cause of migraine per se, may raise the risk of infarction in migraineurs. Hereditary conditions, including CADASIL (cerebral autosomal dominant arteriopathy with sub-cortical infarcts and leukoencephalopathy), MELAS (mitochondrial myopathy, encephalopathy, lactacidosis and stroke) and hereditary haemorrhagic telangiectasia, appear to predispose to both migraine and stroke. Purported mechanisms for migraine-associated stroke include involvement of the vasculature (including vasospasm, arterial dissection and small vessel arteriopathy), hypercoagulability (elevated von Willebrand Factor, platelet activation) and elevated risk of cardioembolism (patent foramen ovale, atrial septal aneurysm). Triptans and ergotamines, used to treat acute migraine attacks, appear to be safe in low-risk populations. These medications should be avoided in persons with haemiplegic migraine, basilar migraine, vascular risk factor and prior cerebral or cardiac ischaemia.

Headache as a surrogate marker of the molecular mechanisms implicated in progressing stroke

The mechanism for headache in patients with acute ischaemic stroke are not completely understood. We analysed the relationship between headache and the early worsening of neurological symptoms in patients with acute ischaemic stroke, and we studied the possible biochemical mechanisms implicated. Headache at the onset of ischaemic stroke predicted progression with a sensitivity, specificity, and positive predictive value of 56%, 99%, and 98%, respectively. CSF concentrations of glutamate, Interleukin-6, and NO-m were significantly greater in patients with progressing stroke than in patients with nonprogressing stroke, and these biochemical markers were also significantly higher in patients with headache than in those without headache. Results of this study suggest that headache at the onset of ischaemic stroke is an independent predictor of neurological worsening and we hypothesize that headache might be a surrogate marker of the molecular mechanisms involved in neurological worsening after acute stroke.

An analysis of excitatory amino acids, nitric oxide, and prostaglandin E2 in the cerebrospinal fluid of pregnant women: the effect on labor pain

It is still unclear which neurotransmitters are involved in labor pain. We measured the concentrations of excitatory amino acids, nitric oxide, and prostaglandin E2 in the cerebrospinal fluid (CSF) of pregnant women, particularly in those with labor pain. The patients included in the study consisted of women who underwent cesarean delivery either with labor pain (Labor Pain group, n = 40) or without labor pain (Nonlabor Pain group, n = 58). All patients received spinal anesthesia (intrathecal injection of 10-12 mg of bupivacaine) for the operation, and 2 mL of CSF was collected before bupivacaine injection. Concentrations of aspartate and glutamate (0.50 +/- 0.06 microM and 0.79 +/- 0.10 microM, respectively) were significantly larger in the Labor Pain group than in the Nonlabor Pain group (0.35 +/- 0.03 microM and 0.54 +/- 0.04 microM, P < 0.05). There were no significant differences in the concentrations of nitric oxide and prostaglandin E2 between the groups. A positive correlation was found between CSF concentrations of excitatory amino acids and labor pain.

IMPLICATIONS

The excitatory amino acids, aspartate and glutamate, play a role in labor pain. N-methyl-D-aspartate receptor antagonists may be useful for labor pain and postlabor uterine contraction pain relief.

Analysis of amino acids in human serum by isocratic reversed-phase high-performance liquid chromatography with electrochemical detection

A simple, sensitive and reproducible isocratic high-performance liquid chromatography (HPLC) method has been developed for the determination of amino acids in human serum. The method involves precipitation of the serum proteins with methanol followed by pre-column derivatization of amino acids with o-phthalaldehyde-2-mercaptoethanol or o-phthalaldehyde-sodium sulfite. HPLC separation of the derivatives was performed using an ODS column with an isocratic mobile phase system and electrochemical detection (+0.75 V). The response was linear over the range 5-300 microM for all amino acids. The method allows quantitative determination of glutamic acid, asparagine, serine, glutamine, histidine, taurine, alanine, arginine, methionine, isoleucine, ornithine, leucine, phenylalanine, lysine and tryptophan at concentrations as low as 0.5-5.0 pmol (signal-to-noise ratio=2). Using this method, the levels of amino acids in serum from healthy donors and patients with ischemic stroke were determined.

Simultaneous determination of several amino acids, including homocysteine, cysteine and glutamic acid, in human plasma by isocratic reversed-phase high-performance liquid chromatography with fluorimetric detection

A method for the simultaneous measurement of two biologically important thiol compounds cysteine and homocysteine and five amino acids including neurotransmitters aspartate and glutamate is reported. This method utilized derivatization of compounds with o-phthalaldehyde in the presence of 2-mercaptoethanol following alkylation of the free sulfydryl group with iodoacetic acid followed by separation using reversed-phase high-performance liquid chromatography. These o-phthalaldehyde-2-mercaptoethanol-labeled compounds were separated within 30 min on a Spherisorb ODS-2 column with isocratic elution using 17% methanol, 0.04 M sodium phosphate buffer (pH 7.0), 0.002 M Na2EDTA and detected fluorimetrically (excitation 340 nm, emission 450 nm). Using this method, the concentrations of homocysteine, cysteine, glutamic acid. aspartic acid, asparagine, serine and glutamine in human plasma were determined.