Wojciech Kozubski

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.

Upregulation of CD40 ligand and enhanced monocyte-platelet aggregate formation are associated with worse clinical outcome after ischaemic stroke

The white blood cell count and mean platelet volume determined shortly after the symptom onset are known as independent predictors for clinical outcome after stroke. In the present study we sought to evaluate the prognostic value of platelet-derived inflammatory biomarkers measured prospectively after an ischaemic event. Using five-colour flow cytometry, the platelet surface expression of CD40L, CD62P and subpopulations of leukocyte-platelet aggregates were assessed in 93 stroke patients on the first (V(0)), 10th (V(1)) and 90th (V(2)) day after stroke, and once in 65 disease controls. The clinical outcome was evaluated using the Scandinavian Stroke Scale (SSS) and modified Rankin Scale (mRS) at the same time points as blood sampling and 24 months after the event. Patients with either CD40L surface expression or the percentage of monocyte-platelet aggregates (M-plt) in the third tertile (T3) at V0 had a significantly lower score on the SSS at V(1). Patients with the percentage M-plt at V(0) higher than the median value of M-plt in controls were at increased risk of SSS < 40 at V(1) (odds ratio: 2.6; 95% confidence interval [CI]: 1.4 - 8.7; p=0.006). Patients with the percentage of M-plt in T3 at V(0) showed progressive decline in survival (hazard ratio [HR]: 1.6; 95% CI: 1.1-1.9; p=0.02) and a significantly higher number of recurrent vascular events (HR: 2.64; 95% CI: 1.3-3.2; p=0.02) when compared to the first tertile. In conclusion, increased levels of M-plt could be a predictive marker for both early outcome and long-term prognosis while increased CD40L was correlated with worse clinical outcome.

Molecular basis of familial and sporadic Alzheimer's disease.

Alzheimers disease (AD) is a multifactorial disease with genetic (70%) and environmental (30%) causes. Among the genetic factors are genes associated with a family history of the disease (familial AD, FAD) and sporadic AD (SAD). The genes: APP (amyloid precursor protein), PSEN1 (Presenilin 1) and PSEN2 (Presenilin 2) are responsible for the presence of FAD. The APOE gene is responsible for the sporadic form of the disease. Other molecular factors related to the immunological cause (TREM2) of the disease are a disorder of the lipid (ABCA1, ABCA7) or biothiol (MTHFD1) metabolism and of the transport of metabolites (BIN1). Currently, it is believed that APOE is a risk factor for both SAD and late-onset FAD. The pathomechanism of AD is most commonly explained as based on the amyloid cascade theory. This theory is related to the FAD, although there are reports indicating the probability of its occurrence in the SAD. It seems that the excessive deposition of β-amyloid (Aβ) peptides and intracellular neurofibrillary tangles of tau protein hyperphosphorylated forms contribute to the damage of both DNA and RNA. Furthermore, it is believed that RNA-interference can affect both the level of pathological proteins (Aβ, tau protein) and the onset and progress of AD. It seems that a complete understanding of both FAD and SAD pathogenesis may contribute to the search for earlier clinical diagnosis and to an understanding of later occurrence of the disease, which may help modify its course and affect more effective therapy of this incurable neurological disease.

Enhanced platelet-derived microparticle formation is associated with carotid atherosclerosis in convalescent stroke patients

Platelets participate in the development and progression of atherosclerosis. During this process they interact with endothelial cells and leukocytes. Therefore, we investigated the associations between carotid atherosclerosis and platelet reactivity markers. The platelet surface expression of P-selectin (CD62P) and the activated GPIIb/IIIa receptor (corresponding to increased binding of PAC-1), as well as the fraction of platelet-derived microparticles (PMPs) prior to and after platelet stimulation with TRAP or ADP, were determined using flow cytometry in 94 subjects in the convalescent phase of ischaemic stroke and in 76 disease controls. The mean common carotid intima-media thickness (CCAmean IMT), maximal common carotid IMT (CCAmax IMT) and maximal bifurcation IMT (BIFmax IMT) were measured bilaterally using B mode, colour Doppler ultrasonography. In stroke subjects IMT within CCA and BIF were greater than in disease controls and the percentage of PMPs prior to and after ex vivo stimulation with agonists was significantly higher than in controls. Multiple regression analysis revealed that PMPs were positively and independently correlated with both CCAmean IMT ( β = 0.23; p < 0.01) and stroke ( β = 0.21; p<0.01), while PAC-1 binding to platelets activated with ADP was negatively and independently associated with CCAmean IMT ( β = −0.29; p<0.001) and atherosclerotic carotid plaque presence ( β = −0.28, p = 0.003). We found a positive association between enhanced PMP formation and atherosclerotic thickening of carotid intima-media or carotid plaque in patients after ischaemic stroke. We demonstrated that diminished expression of active GPIIb/IIIa in the ADP-activated platelets is associated with increased carotid IMT, independently of stroke.

Post‐stroke quality of life and depression

Background: Studies on the determinants of the quality of life (QOL) after stroke bring differing results depending on the applied concept of QOL. This may lead to confusion about the contribution of various factors to the post-stroke QOL. Objective: The aim of the study was: (i) to investigate functional and psychological QOL in the individuals after the first ischemic stroke; (ii) to identify the most important correlates of QOL; and (iii) to examine the significance of depression among the other possible predictors of QOL. Methods: A hospital-based sample of 72 stroke patients was followed up to 6 months after stroke onset. QOL was assessed using the Polish version of the Quality of Life Index and the Sickness Impact Profile. A multiple regression procedure was performed to examine relationships between QOL and the study variables. Results: In spite of good recovery, the psychological and functional QOL of the examined patients was impaired, although the negative impact of stroke was greater on the objective QOL than on the subjective QOL. Stroke-related impairment, depression, functional disability and marital status predicted 80% of the variance in the functional QOL. Emotional support, depression and functional disability explained 38% of the variance in psychological well-being. Conclusions: Depression and physical disability were the most important predictors of QOL after stroke since their impact on QOL was more robust in comparison to the remaining variables. For improving QOL, a comprehensive care for patients aimed at reducing physical dependence and ameliorating depressive symptoms could be recommended.

Polymorphism of the COMT, MAO, DAT, NET and 5-HTT Genes, and Biogenic Amines in Parkinson's Disease.

Epinephrine (E) and sympathetic nerve stimulation were described by Thomas Renton Elliott in 1905 for the first time. Dopamine (DA), norepinephrine (NE), E, and serotonin (5-HT) belong to the classic biogenic amines (or monoamines). Parkinson’s disease (PD) is among the diseases in which it has been established that catecholamines may account for the neurodegeneration of central and peripheral catecholamine neural systems. PD is a chronic and progressive neurological disorder characterized by resting tremor, rigidity, and bradykinesia, affecting 2% of individuals above the age of 65 years. This disorder is a result of degeneration of DA-producing neurons of the substantia nigra and a significant loss of noradrenergic neurons in the locus coeruleus. In PD and other related neurodegerative diseases, catecholamines play the role of endogenous neurotoxins. Catechol-O-methyltransferase (COMT) and/or monoamine oxidase (MAO) catalyze the metabolism of monoamines. However, the monoamine transporters for DA, NE, and 5-HT namely DAT, NET, and SERT, respectively regulate the monoamine concentration. The metabolism of catecholamines and 5-HT involves common factors. Monoamine transporters represent targets for many pharmacological agents that affect brain function, including psychostimulators and antidepressants. In PD, polymorphisms of the COMT, MAO, DAT, NET, and 5- HTT genes may change the levels of biogenic amines and their metabolic products. The currently available therapies for PD improve the symptoms but do not halt the progression of the disease. The most effective treatment for PD patients is therapy with L-dopa. Combined therapy for PD involves a DA agonist and decarboxylase, MAOs and COMT inhibitors, and is the current optimal form of PD treatment maintaining monoamine balance.

MTHFR, MTR, and MTHFD1 gene polymorphisms compared to homocysteine and asymmetric dimethylarginine concentrations and their metabolites in epileptic patients treated with antiepileptic drugs

PURPOSE The purpose of the study was to determine the frequency of occurrence of polymorphisms of genes MTHFR (C677T), MTR (A2756G), and MTHFD1 (G1958A), as well as to analyze the concentration of homocysteine (Hcy), methionine (Met), asymmetric dimethylarginine (ADMA), and arginine (Arg) in epileptics treatment with antiepileptic drugs (AEDs), and controls. METHOD The study included 65 epileptic patients treated with variable AEDs and 61 controls. The levels of Hcy and Met were determined by HPLC/EC, ADMA and Arg by HPLC with fluorescence detection. Polymorphisms of the studied genes were determined by PCR-RFLP. RESULTS The study demonstrates that AEDs treatment in epileptics leads to increase in Hcy (p<0.05) and ADMA (p<0.01) concentrations. Greater increases in Hcy concentration during AEDs treatment appear to occur in individuals with the MTHFR CT (C677T) and MTHFD1 GG (G1958A) genotypes. Genetic conditions also appear to be related with changes in the ratios of Hcy, Met, Arg, and ADMA. It seems that in cases of AEDs treatments effect on hyperhomocysteinemia, epileptic individuals appear to have a disturbed control of Hcy over ADMA. CONCLUSIONS It is possible, that polymorphisms of genes related to Hcy-to-Met metabolism, in epileptics treated with AEDs may have an effect on the regulation of levels of risk factors of vascular diseases, Hcy and ADMA.

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.

Common carotid artery remodeling studied by sonomorphological criteria.

Background and Purpose. Only a few attempts have been made to establish the impact of critical intima‐media thickness (IMT) on narrowing of the lumen of the common carotid artery (CCA). In the present study, sonomorphological criteria have been used to assess how intima‐media thickening in the CCA may influence the artery geometry.Methods. High‐resolution ultrasonography was employed in 233 patients (466 arteries) to quantify the selected parameters of CCA biometry: IMT, arterial lumen diameter (LD), interadventitial diameter (IAD), and outer artery diameter (OAD).Results. With an increase of CCA IMT up to the critical point of 1.2 mm, the LD showed parallel compensatory increases. Above the inflection point of 1.3 mm, the lumen became progressively narrower proportionally to the increasing IMT.Conclusion. There are limits to the compensa‐tory enlargement of the CCA lumen. Above the inflection point of CCA IMT of 1.3 mm, the artery lumen becomes progressively narrower with increasing IMT.