Slawomir Michalak

Serum tight-junction proteins predict hemorrhagic transformation in ischemic stroke patients

Objective: To evaluate the significance of circulating tight-junction (TJ) proteins as predictors of hemorrhagic transformation (HT) in ischemic stroke patients. Methods: We examined 458 consecutive ischemic stroke patients, 7.2% of whom had clinically evident HT. None of the patients was treated with thrombolytic drugs. Serum levels of standard markers of blood–brain barrier (BBB) breakdown (S100B, neuron-specific enolase), TJ proteins (occludin [OCLN], claudin 5 [CLDN5], zonula occludens 1 [ZO1]), and molecules involved in BBB disintegration (matrix metalloproteinase 9 and vascular endothelial growth factor [VEGF]) were assessed upon admission to the emergency department. A clinical deterioration caused by HT (cdHT) was defined as an increase of ≥4 points in the NIH Stroke Scale score in combination with a visible HT on a CT scan performed immediately after the onset of new neurologic symptoms. Results: Patients with cdHT had higher concentrations of OCLN, S100B, and the CLDN5/ZO1 ratio, and a lower level of VEGF than those without cdHT. CLDN5 levels also correlated with cdHT occurrence when estimated within 3 hours of stroke onset. We also demonstrated correlations between the levels of circulating TJ molecules and the level of S100B, which is a previously established marker of BBB disruption. Conclusions: Analyzing serum levels of TJ proteins, like CLDN5, OCLN, and CLDN5/ZO1 ratio, as well as S100B and VEGF, is an effective way to screen for clinical deterioration caused by HT in ischemic stroke patients, both within and after the IV thrombolysis time window.

Platelet activation and reactivity in the convalescent phase of ischaemic stroke

The study was aimed at the evaluation of blood platelet activation and reactivity in patients in the convalescent phase of stroke (n=58) and controls matched in respect to risk factors of vascular pathology (n=55). Both groups were treated daily with acetylsalicylic acid (ASA), 150 mg/day. Using flow cytometry, the expressions of P-selectin and the active GP IIb/IIIa receptor, as well as the fraction of platelet-derived microparticles (PMPs) and total platelet aggregates (Ag), were evaluated in non-stimulated platelets and in platelets stimulated in vitro by thrombin, thrombin receptor activating peptide (TRAP) or ADP. The expression of P-selectin in non-stimulated platelets was found to be significantly (p=0.04) lower in stroke patients. In parallel, these patients manifested a significantly (p=0.0008) higher proportion of PMPs and a lowered (p=0.003) proportion of Ag, as compared to the controls. In the stroke patients the increased expressions of P-selectin and active GP IIb/IIIa in TRAP- or ADP-activated cells were less pronounced (p<0.01), while the increments in PMP fraction remained higher (p<0.05). Our results may indicate that chronic platelet activation develops in patients in the convalescent phase of stroke and the process of PMP generation prevails over blood platelet degranulation and aggregation. This shift may be particularly unfavourable due to the procoagulative and proatherosclerotic properties of PMPs, accompanied by their decreased sensitivity to the action of antiplatelet drugs.

Anti-inflammatory cytokines in subclinical carotid atherosclerosis

Some studies have shown correlations between selected proinflammatory factors and carotid atherosclerosis. It has not been established whether anti-inflammatory cytokines are associated with carotid intima–media thickness (IMT), an ultrasound surrogate marker of atherosclerosis. Therefore, the authors studied the relationship between the carotid IMT and serum levels of interleukin (IL)-10 and transforming growth factor-β1 in 76 subjects. They discovered that lower IL-10 levels were associated with increased mean IMT in common carotid arteries.

The Immunology of Neuromyelitis Optica—Current Knowledge, Clinical Implications, Controversies and Future Perspectives

Neuromyelitis optica (NMO) is an autoimmune, demyelinating disorder of the central nervous system (CNS) with typical clinical manifestations of optic neuritis and acute transverse myelitis attacks. Previously believed to be a variant of multiple sclerosis (MS), it is now considered an independent disorder which needs to be differentiated from MS. The discovery of autoantibodies against aquaporin-4 (AQP4-IgGs) changed our understanding of NMO immunopathogenesis and revolutionized the diagnostic process. AQP4-IgG is currently regarded as a specific biomarker of NMO and NMO spectrum disorders (NMOsd) and a key factor in its pathogenesis. Nevertheless, AQP4-IgG seronegativity in 10%–25% of NMO patients suggests that there are several other factors involved in NMO immunopathogenesis, i.e., autoantibodies against aquaporin-1 (AQP1-Abs) and antibodies against myelin oligodendrocyte glycoprotein (MOG-IgGs). This manuscript reviews current knowledge about NMO immunopathogenesis, pointing out the controversial issues and showing potential directions for future research. Further efforts should be made to broaden our knowledge of NMO immunology which could have important implications for clinical practice, including the use of potential novel biomarkers to facilitate an early and accurate diagnosis, and modern treatment strategies improving long-term outcome of NMO patients.

The Early Effect of Carotid Artery Stenting on Antioxidant Capacity and Oxidative Stress in Patients with Carotid Artery Stenosis

The treatment of carotid artery stenosis is associated with the risk of complications, which may include stroke after carotid artery stenting (CAS) and myocardial infarction after carotid endarterectomy (CEA). The imbalance between prooxidative mechanisms and antioxidant capacity creates a milieu of factors, which may increase the risk of complications after endovascular procedures. We have examined 43 consecutive patients with carotid artery stenosis. Sera were analyzed for the activity of paraoxonase (PON) and arylesterase (ARE), sulfhydryl groups (SG), malondialdehyde (MDA), and conjugated dienes (CD) concentrations by means of spectrophotometric methods before and next day after CAS. We have found lowered PON (P = 0.0032), increase in ARE activity (P = 0.0058), and decrease in sulfhydryl groups concentration (P = 0.0267). No effect on absolute MDA and CD concentrations was observed. The degree of carotid artery stenosis correlated negatively with PON/ARE ratio after CAS (r S = −0.507, P = 0.0268). To conclude, CAS influences both enzymatic (differently, PON and ARE activity) and nonenzymatic antioxidant defense. Females are more susceptible to lipid peroxidation after CAS. PON/ARE ratio after CAS correlated with the degree of carotid artery stenosis. The changes (deltas) in ARE activity, SG, and MDA concentrations correlated with the severity of neurological deficit and disability.

Role of Lipid Peroxidation Products, Plasma Total Antioxidant Status, and Cu-, Zn-Superoxide Dismutase Activity as Biomarkers of Oxidative Stress in Elderly Prediabetics

The relationship between hyperglycemia and oxidative stress in diabetes is well known, but the influence of metabolic disturbances recognized as prediabetes, in elderly patients especially, awaits for an explanation. Methods. 52 elderly persons (65 years old and older) with no acute or severe chronic disorders were assessed: waist circumference (WC), body mass index (BMI), percentage of body fat (FAT), and arterial blood pressure. During an oral glucose tolerance test (OGTT) fasting (0′) and 120-minute (120′) glycemia and insulinemia were determined, and type 2 diabetics (n = 6) were excluded. Subjects were tested for glycated hemoglobin HbA1c, plasma lipids, total antioxidant status (TAS), thiobarbituric acid-reacting substances (TBARS), and activity of erythrocyte superoxide dismutase (SOD-1). According to OGTT results, patients were classified as normoglycemics, (NGT, n = 18) and prediabetics, (PRE, n = 28). Results. Both groups did not differ with their lipids, FAT, and TBARS. PRE group had higher WC (P < 0.002) and BMI (P < 0.002). Lower SOD-1 activity (P < 0.04) and TAS status (P < 0.04) were found in PRE versus NGT group. Significance. In elderly prediabetics, SOD-1 and TAS seem to reflect the first symptoms of oxidative stress, while TBARS are later biomarkers of oxidative stress.

Neurological Paraneoplastic Syndromes in Lung Cancer Patients

Lung cancer is recognized among the most frequent causes of paraneoplastic neurological syndromes (PNS). Neurological syndromes in subjects with systemic malignancy remain a clinical and diagnostic challenge. The aim of the study was to evaluate the frequency of NPS, their clinical manifestation and association with onconeural antibodies in patients with lung cancer. Fifty patients hospitalized with the diagnosis of PNS participated in the study. Neurological evaluation consisted of the Rankin scale (mRS), the Barthel index (BI), and testing for the presence of onconeural antibodies by means of indirect immunofluorescence, as screening, and Western blotting as confirmation. The majority of lung cancer patients (64%) aged 62 ± 10 had NPS symptoms. Their neurological condition and daily living activities were reasonable: mRS (1.0; 0.0-4.0) and BI (100; 7.4-100) scores. Classical PNS were found in 30% of cases and included sensory neuropathy (16%), paraneoplastic cerebellar degeneration (12%) as the most frequent symptoms. Autoimmune reaction was observed in 42% of lung cancer patients and in 20% was represented by well-characterized onconeural antibodies. Anti-Hu antibody was identified as the most frequent. In conclusion, PNS signs in lung cancer patients have both classical and non-classical features. In the course of SCLC only well-characterized onconeural antibodies were identified. The presence of well-characterized onconeural antibodies is strongly associated with classical features of PNS.

Reactive leptin resistance and the profile of platelet activation in acute ischaemic stroke patients

Leptin is an adipokine that in vitro enhances agonist-induced platelet aggregation and adipokine expression. Hyperleptinaemia represents a risk factor for cardiovascular disease. We conducted a prospective evaluation of the potential link between blood platelet activation and plasma leptin levels in post-stroke patients. Using five-colour flow cytometry, the platelet surface expression of CD40L, CD62P, the subpopulations of monocyte-platelet aggregates and platelet-derived microparticles (PMPs) as well as the plasma leptin, soluble leptin receptor (sOb-R), leptin/sOb-R ratio, the plasma adiponectin, and leptin/adiponectin ratio were assessed in 98 stroke patients on the first (V₀), 10th (V₁ ) and 90th (V₂) day after stroke and once in 78 age-, gender- and vascular risk factor-matched disease controls. We demonstrated that at V0 leptin resistance, defined as leptin/sOb-R ratio, was higher than in the controls [1.1 (0.5-1.8 vs. 0.5 (0.2-1.1); p=0.02]. After adjustment according to the factors which influence platelet activation, we confirmed the relationship between percentage of circulating PMPs and plasma leptin level (B=0.18; p=0.02) or the leptin/sOb-R ratio (B=0.23; p=0.02) in normal-weight subjects in the acute phase of stroke. No correlation could be demonstrated between the adipokine parameters and the percentage of monocyte-platelet aggregates or expression of platelet pro-inflammatory glycoproteins. In conclusion, formation of PMPs on the first day following an ischaemic stroke shows a positive correlation with leptin levels and with resistance to leptin. Leptin level does not seem to affect the expression of platelet surface proinflammatory glycoproteins.

The cross-reactivity of binding antibodies with different interferon beta formulations used as disease-modifying drugs in multiple sclerosis patients

AbstractInterferon beta (IFNb) preparations are commonly used as first-line therapy in relapsing-remitting multiple sclerosis (RRMS). They are, however, characterized by limited efficacy, partly due to the formation of anti-IFNb antibodies in patients.In this pilot study, we assessed with the ELISA method the presence of the binding antibodies (BAbs) against interferon beta after 2 years of therapy with subcutaneous interferon beta 1a (Rebif) in 49 RRMS patients. Antibody levels were established again within 1 year after treatment withdrawal. We used 3 interferons that are commercially available for MS therapy, namely Avonex (Biogen Idec Limited), Rebif (Merck Serono), and Betaferon (Bayer Pharma AG), as antigens.BAbs reacting with Rebif were found in 24.4% to 55% of patients, depending on the units of their expression. The levels of anti-Rebif antibodies remained high in 8 patients and in 4 patients they dropped significantly. Strong correlations were obtained in all assays (anti-Rebif-anti-Avonex, anti-Rebif-anti-Betaferon, and anti-Betaferon-anti-Avonex) and the existence of cross-reactivity in the formation of antibodies against all the tested formulations of interferon beta was confirmed. The levels of BAbs remain significant in the clinical context, and their assessment is the first choice screening; however, methods of BAbs evaluation can be crucial for further decisions. More studies are needed to confirm our results; specifically it would be of interest to evaluate methods of neutralizing antibodies identification, as we only assessed the binding antibodies. Nevertheless, our results support the concept that in interferon nonresponders, that are positive for binding antibodies, switching the therapy to alternative disease-modifying agent (for example glatiramer acetate, fingolimod, or natalizumab) is justified, whereas the switch to another interferon formulation will probably be of no benefit.

The Markers of Glutamate Metabolism in Peripheral Blood Mononuclear Cells and Neurological Complications in Lung Cancer Patients

Objective. To evaluate the involvement of glutamate metabolism in peripheral blood mononuclear cells (PBMC) in the development of neurological complications in lung cancer and during chemotherapy. Methods. The prospective study included 221 lung cancer patients treated with chemotherapeutics. Neurological status and cognitive functions were evaluated at baseline and after 6-month follow-up. Glutamate level, the activities of glutaminase- (GLS-) glutamate synthetizing enzyme, glutamate dehydrogenase (GDH), and glutamate decarboxylase catalyzing glutamate degradation were analyzed in PBMC and in sera of lung cancer patients by means of spectrophotometric and colorimetric methods. Results. Chemotherapy of lung neoplasms induced increase of glutamate content in PBMC and its concentration in serum increased the activity of GDH in PBMC and decreased activity of glutaminase in PBMC. The changes in glutamate metabolism markers were associated with initial manifestation of neurological deficit in lung cancer patients and with new symptoms, which appear as a complication of chemotherapy. Moreover, the analyzed parameters of glutamate control correlated with a spectrum of cognitive functions measures in lung cancer patients. Conclusion. We have demonstrated dysregulation in glutamate and glutamate metabolism controlling enzymes as promising indicators of risk for chemotherapy-induced neurological complications in lung cancer patients with particular emphasis on cognitive impairment.