Factor XII (Hageman factor) is a missing link between stress and hypercoagulability and plays an important role in the pathophysiology of ischemic stroke

Proteomics-Based Approach to Identify Novel Blood Biomarker Candidates for Differentiating Intracerebral Hemorrhage From Ischemic Stroke-A Pilot Study

Background: A reliable distinction between ischemic stroke (IS) and intracerebral hemorrhage (ICH) is required for diagnosis-specific treatment and effective secondary prevention in patients with stroke. However, in resource-limited settings brain imaging, which is the current diagnostic gold standard for this purpose, is not always available in time. Hence, an easily accessible and broadly applicable blood biomarker-based diagnostic test differing stroke subtypes would be desirable. Using an explorative proteomics approach, this pilot study aimed to identify novel blood biomarker candidates for distinguishing IS from ICH.

Material and Methods: Plasma samples from patients with IS and ICH were drawn during hospitalization and were analyzed by using liquid chromatography/mass spectrometry. Proteins were identified using the human reference proteome database UniProtKB, and label-free quantification (LFQ) data were further analyzed using bioinformatic tools.

Results: Plasma specimens of three patients with IS and four patients with ICH with a median National Institute of Health Stroke Scale (NIHSS) of 12 [interquartile range (IQR) 10.5–18.5] as well as serum samples from two healthy volunteers were analyzed. Among 495 identified protein groups, a total of 368 protein groups exhibited enough data points to be entered into quantitative analysis. Of the remaining 22 top-listed proteins, a significant difference between IS and ICH was found for Carboxypeptidase N subunit 2 (CPN2), Coagulation factor XII (FXII), Plasminogen, Mannan-binding lectin serine protease 1, Serum amyloid P-component, Paraoxonase 1, Carbonic anhydrase 1, Fibulin-1, and Granulins.

Discussion: In this exploratory proteomics-based pilot study, nine candidate biomarkers for differentiation of IS and ICH were identified. The proteins belong to the immune system, the coagulation cascade, and the apoptosis system, respectively. Further investigations in larger cohorts of patients with stroke using additional biochemical analysis methods, such as ELISA or Western Blotting are now necessary to validate these markers, and to characterize diagnostic accuracy with regard to the development of a point-of-care-system for use in resource-limited areas.

An explanation of how migraine headaches can trigger relapse in systemic lupus erythematosus

Except for a few diseases of molecular mimicry such as rheumatic fever, post-streptococcal glomerulonephritis in children, and gluten-sensitive enteropathy, the cause of autoimmune diseases is unknown. Most autoimmune diseases are remitting-relapsing and the pathophysiology of either the initial attack or subsequent relapses is a mystery. Migraine headaches in systemic lupus erythematosus patients are statistically associated with disease activity, i.e. the patients with bad lupus are the ones who get migraine. T lymphocytes reactive against self are normally suppressed by immunoregulatory T cells (Tregs), but suppression can be broken by CD28 ligation of Tregs. This raises intracellular levels of H2O2, which is a second messenger in the CD28 signaling cascade. Migraine headaches are often accompanied by systemic platelet activation and a brief but intense platelet oxidative burst which raises extracellular H2O2 levels to the point where H2O2 diffusing passively across lymphocyte cell membranes can raise intracellular H2O2 sufficiently to turn off regulatory T cell function via the CD28 signaling cascade. Passive diffusion of H2O2 mimics the effect of H2O2 formation triggered by CD28 ligation. This eliminates the immunosuppressive hold of Tregs on self-reactive T cells and the development or worsening of autoimmune disease ensues spontaneously.

Atherosclerosis, venous thromboembolism and migraine: what are the associated risks?

There is a certain amount of literature suggesting that migraine is indirectly linked to an enhanced risk of atherosclerosis. Unfortunately, however, no explanation or true confirmation of this association has been provided. A recent study suggested that the burden of atherosclerosis at carotid and femoral arteries does not differ between migrainous and nonmigrainous patients, although there is an increased risk of venous thromboembolism in migrainous patients. No link between atherosclerosis and migraine was apparent, but the association between migraine and venous thrombolism requires further investigation. Some hypotheses on this complex issue are discussed in this article.

Rapid development of chylothorax in patient with propofol-induced coma

A woman presented with new onset of a progressive ataxia. Subsequently, she underwent resection of a ponto-cerebellar maeningioma. Ten days later a chylothorax developed. Although the exact aetiology of the chylothorax is unclear, an acute obstruction of common chyle duct with a concomitant lipophilic infusion of propofol seems most likely to be a culprit for rapid increase in the size of the pleural effusions.

Temporal lobe epilepsy is a disease of faulty neuronal resonators rather than oscillators, and all seizures are provoked, usually by stress

Temporal lobe epilepsy (TLE) is the most common cause of intractable adult epilepsy. It is proposed that different kinds of epilepsy be classified into one of two categories, which correspond to the two basic kinds of neurons in the brain, that is, as diseases of oscillators or as diseases of resonators. Oscillator (or pacemacker) neurons are endowed with intrinsic conductances that permit periodic spontaneous generation of action potentials; in contrast, resonators are neurons which process information coming from sensory stimuli or from other neurons. A literature review supports the idea that TLE is a disease of faulty resonators. This means that seizures do not arise de novo in the seizure focus. The seizure focus responds to normal input with an abnormally large discharge that causes seizures. The most frequent trigger for TLE is psychological stress. A previously published theory of stress is reviewed. The stress circuit runs from the hippocampus to the amygdala to the dorsal raphe nucleus to the entorhinal cortex and back to the hippocampus. Cell loss in the dentate is central to the pathophysiology of both chronic stress and TLE, which establish a "vicious circle" relationship with one another. Once it is grasped that TLE is a disease of resonators and that all seizures in TLE are triggered, then it makes sense to address the major recognized trigger, which is stress. New therapeutic ideas for decreasing seizure frequency in TLE include the use of anti-depressants, ethosuximide (which blocks firing in the dorsal raphe nucleus), and mood-stabilizers (which block firing in the entorhinal cortex). The latter category includes several recognized anti-epileptic drugs. Drugs from all three categories should be used simultaneously and on an empirical basis in each patient.

Redrawing Papez’ circuit: A theory about how acute stress becomes chronic and causes disease

The diseases of chronic stress include migraine, essential hypertension, depression, and the metabolic syndrome. A theory is presented to explain how acute stress becomes chronic and causes these inter-related conditions. The theory is based on a new "circuit of emotion", which is derived from Papez' famous theory of emotion. The hypothesis is as follows: There is a basic circuit of emotion which runs from the hippocampus (defined as the dentate gyrus plus the CA regions), where emotion arises, to the amygdala and from there to serotonergic pacemaker cells in the dorsal raphe nucleus (DRN). The DRN projects back to the dentate gyrus in two ways: a direct route without a stop and an indirect route via pacemaker cells in the entorhinal cortex. The purpose of the direct route is to promote neurogenesis in the subgranular zone of the dentate; the indirect route has two purposes: to imprint ongoing moments of consciousness onto new dentate cells for retention as memory and to provide a negative feedback loop for regulation of the whole process. The hippocampus, the amygdala, and the DRN all project to the hypothalamus, which are branches off the basic loop that subserve the autonomic expression of emotion. Pathologic overdrive of the DRN causes overdrive of the entorhinal cortex, which leads to excitotoxic cell death of neurons in the hippocampus involved in the negative feedback loop. The disinhibited amygdala and DRN are then free to orchestrate the syndromes of chronic stress. Recovery from chronic stress requires repopulation of the dentate gyrus and restoration of the feedback loop. Excitotoxic cell death in the hippocampus results from either extraordinary acute stress or increased susceptibility to DRN overdrive, as might be caused, for example, by genetic factors, age, high cortisol levels, or incomplete recovery from previous damage. Three goals for therapeutic intervention are identified: inhibition of pacemaker cells in the DRN (which can be targeted by ethosuximide and other drugs that block serotonergic pacemaker currents), inhibition of pacemaker cells in the entorhinal cortex (which can be targeted by anti-epileptic drugs that block pacemaker currents in the entorhinal cortex, e.g. phenytoin), and restoration of serotonin levels in the dentate gyrus (which can be accomplished with anti-depressants). It is logical to use drugs from all three categories, either alone on in combination, to treat any of the four diseases of chronic stress. This leads to novel therapeutic recommendations, e.g. the use of ethosuximide, mood-stabilizers, and anti-depressants in synergy to treat essential hypertension.

A new theory of cryptogenic stroke and its relationship to patent foramen ovale; or, the puzzle of the missing extra risk

Cryptogenic stroke (or stroke of undetermined cause) is a common cause of stroke and is statistically associated with patent foramen ovale (PFO). The largest study of cryptogenic stroke is the Homma study, which is a sub-study of the WARSS trial; it produced the following data: cryptogenic stroke patients with and without PFO, when treated with either aspirin or warfarin, all had identical recurrence rates. This is puzzling because it seems as though there ought to have been some extra risk in one of the two groups under one of the two treatments. How could everything come out the same? A review of the epidemiology of cryptogenic stroke shows that, compared to patients with stroke of determined cause, cryptogenic stroke patients are a little younger and have lower doses of the usual risk factors (hypertension and diabetes mellitus) but more PFO. Cryptogenic strokes appear to be embolic strokes from an unknown source. A previously published article setting forth a hypothetical theory of stress-induced stroke was used to analyze these data. It is suggested that stress can induce episodic systemic platelet activation and hypercoagulability, which causes transient thrombus formation and subsequent embolization on both the arterial and venous sides of the circulation; the latter requires a PFO to cause a stroke (paradoxical embolism). The sum of these two mechanisms explains cryptogenic stroke. The PFO subset of cryptogenic stroke includes patients with both early and late stage disease who have an aggregate risk approximately equal to that of patients without PFO. Cryptogenic stroke is part of the disease of stress-induced cerebrovascular disease. Aspirin and warfarin have already been shown to be equally effective in secondary prevention of ischemic stroke.