Particulate Air Pollution, Clock Gene Methylation, and Stroke: Effects on Stroke Severity and Disability.

Circadian rhythm disturbances have been consistently associated with the development of several diseases, particularly cardiovascular diseases (CVDs). A central clock in the brain maintains the daily rhythm in accordance with the external environment. At the molecular level, the clock is maintained by "clock genes", the regulation of which is mainly due to DNA methylation, a molecular mechanism of gene expression regulation, able to react to and be reprogrammed by environmental exposure such as exposure to particulate matter (PM). In 55 patients with a diagnosis of acute ischemic stroke, we showed that PM2.5 exposure experienced before the event influenced clock genes methylation (i.e., circadian locomotor output cycles protein kaput CLOCK, period 2 PER2, cryprochrome 1 CRY1, Neuronal PAS Domain Protein 2 NPAS2), possibly modulating the patient prognosis after the event, as cryptochrome 1 CRY1 and period 1 PER1 methylation levels were associated with the Rankin score. Moreover, if PM2.5 annual average was low, CRY1/CRY2 methylation levels were positively associated with the National Institutes of Health Stroke Scale (NIHSS) score, whereas they were negatively associated if PM2.5 exposure was high. Whether epigenetic changes in clock genes need to be considered as a prognostic marker of stroke or rather a causal agent in stroke development remains to be determined. Further studies are needed to determine the role of clock gene methylation in regulating the response to and recovery after a stroke event.

The Role of Extracellular Vesicles in Ischemic Stroke Severity.

The possibility of characterizing the extracellular vesicles (EVs) based on parental cell surface markers and their content makes them a new attractive prognostic biomarker. Thus, our study aims to verify the role of EVs as relevant prognostic factors for acute and mid-term outcomes in ischemic stroke. Forty-seven patients with acute ischemic stroke were evaluated at admission (T0), immediately after recanalization treatment or after 2 h in non-treated patients (T1) and after one week (Tw) using the National Institutes of Health Stroke Scale (NIHSS), and after 3 months using the Modified Rankin Scale (mRS). Total count and characterization of EVs were assessed by Nanosight analysis and flow cytometry. The relationships between stroke outcomes and EV count were assessed through multivariable negative binomial regression models. We found that the amount of platelet-derived EVs at admission was positively associated with the severity of ischemic stroke at the onset as well as with the severity of mid-term outcome. Moreover, our study revealed that T-cell-derived EVs at admission were positively related to both early and mid-term ischemic stroke outcomes. Finally, T-cell-derived EVs at T1 were positively related to mid-term ischemic stroke outcome. The present study suggests that specific EV subtypes are associated with stroke severity and both short- and long-term outcomes. EVs could represent a valid tool to improve risk stratification in patients with ischemic stroke and post-recanalization treatment monitoring.

Cardiac Autonomic Derangement is Associated with Worse Neurological Outcome in the Very Early Phases of Ischemic Stroke.

BACKGROUND: Acute ischemic stroke (AIS) is associated with autonomic dysfunction. We evaluated the prognostic value of heart rate variability (HRV) and the role of stroke localization and reperfusion treatment (RT) on autonomic control. METHODS: Patients with AIS and sinus rhythm were enrolled in the emergency department. Autonomic parameters were recorded at the onset and after a potential RT. Neurological deficit was assessed using the National Institute of Health Stroke Scale (NIHSS) at the onset and residual disability with modified Rankin Scale (mRS) at 3 months. Two analyses were used to assess HRV. Low frequency (LF) and high frequency (HF) are, respectively, markers of sympathetic and respiratory vagal modulation in spectral analysis. Symbolic analysis provides pattern with no variation (0V%) as an index of sympathetic modulation and pattern with two like variations (2LV%) and pattern with two unlike variations (2UV%) as markers of vagal modulation. RESULTS: We enrolled 41 patients. Twenty-seven underwent RT. A prevalent parasympathetic modulation was found in patients with NIHSS ≥14. The group with mRS 3-6 exhibited a higher 2UV% and lower 0V%. Right-sided strokes were associated with a higher respiratory vagal control. RT had no effects on HRV parameters. CONCLUSIONS: In the very early phases of AIS, a decreased 0V% and an increased 2UV% may reflect a loss of sympathetic oscillation, predicting a poorer 3 month-outcome.

A bioclinical pattern for the early diagnosis of cardioembolic stroke.

Background and Scope. Early etiologic diagnosis of ischemic stroke subtype guides acute management and treatment. We aim to evaluate if plasma biomarkers can predict stroke subtypes in the early phase from stroke onset. Methods. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP), D-dimer, C-reactive protein, serum albumin, and globulin levels have been investigated in 114 consecutive patients presenting at the emergency room within 6 hours of the ischemic stroke onset. Plasma levels of biomarkers have been correlated with stroke aetiology (based on TOAST criteria) by multivariable logistic regression analysis, adjusted for several covariates. Results. Of the 114 patients, 34 (30%) had cardioembolic stroke, 27 (23%) atherothrombotic stroke, 19 (17%) lacunar stroke, and 34 (30%) stroke of undetermined origin. Patients with cardioembolic stroke had significantly higher levels of NT-proBNP and lower globulin/albumin (G/A) ratio compared with the other subgroups. At multiple logistic regression NT-proBNP > 200 pg/mL, G/A ratio > 0.70, and NIHSS score were independent predictors of cardioembolic stroke with high accuracy of the model, either including (AUC, 0.91) or excluding (AUC, 0.84) atrial fibrillation. Conclusions. A prediction model that includes NT-proBNP, G/A ratio, and NIHSS score can be useful for the early etiologic diagnosis of ischemic stroke.

Mitochondrial DNA G8363A mutation in the tRNA Lys gene: clinical, biochemical and pathological study.

The G8363A is a very rare mtDNA tRNA(Lys) gene mutation that has been associated to MERRF-like syndrome, cardiomyopathy or Leigh syndrome. Here, we describe the clinical and molecular features of a new large multigenerational family and we review the literature of cases with this mutation. In our family seven members presented a heterogeneous mitochondrial disease phenotype, from MERRF-like syndrome to isolated psychiatric disorder, associated with the G8363A mutation. The two probands are dizygotic twin sisters affected by mental retardation, neural deafness, myopathy, myoclonic epilepsy and ataxia. Twins' muscle biopsies showed a severe cytochrome c oxidase (COX) deficiency and ragged-red fibers. Their mitochondrial respiratory chain was defective in complexes I and IV in muscle. A severe reduction in complex IV activity was also observed in fibroblasts and myoblasts. Molecular analysis showed a G8363A transition in the mtDNA tRNA(Lys) gene. The mutation was almost homoplasmic (>90%) in muscle and blood of the twins and heteroplasmic (55+/-8%) in blood sample from affected maternal relatives. Based on our family data and the meta-analysis of the literature, we confirm that mutational load directly correlates with severity of the disease (severe vs mild/moderate phenotype; P=0.00168) and with disease onset (P<0.00001). However the presence of several exceptions and overlaps among patients with different clinical severity limits the clinical usefulness of this observation. Although the pathogenicity of the G8363A mutation is well established, counselling is a difficult task for clinicians because of the large phenotypical variability. Our study contributes further data on the clinical spectrum and its relation with the level of G8363A tRNA(Lys) mtDNA mutation.

Gastroduodenal lesions in polycythaemia vera: frequency and role of Helicobacter pylori.

The prevalence of gastroduodenal lesions is higher in polycythaemia vera (PV) than in the general population. However, the role of Helicobacter pylori (H. pylori) in the pathogenesis of such lesions is unknown. The aim of our study was to evaluate the prevalence of gastroduodenal lesions in PV patients and dyspeptic controls, and to assess the role of PV and H. pylori infection in inducing them. Thirty-five PV patients fulfilling selection criteria and 73 age- and sex-matched controls underwent upper gastrointestinal endoscopy. Six gastric mucosal biopsies were taken in all patients and controls, and analysed for presence of H. pylori; serum anti-CagA was assayed by Western blot. Data were analysed with descriptive statistics and multivariate regression analysis. Compared with controls, PV patients showed a significantly higher frequency of erosions (46% versus 12%), ulcers (29% versus 7%), H. pylori positivity (83% versus 57%), and anti-CagA positivity (66% versus 37%). Fourteen out of 20 (70%) asymptomatic PV patients had gastroduodenal lesions. At multivariate analysis, H. pylori, presence of PV alone, and both PV and anti-CagA were significantly and strongly associated with a higher frequency of gastroduodenal lesions (P < 0.05, P < 0.01 and P < 0.05 respectively). Both PV and H. pylori infection were independent risk factors for gastroduodenal lesions; the underlying pathogenetic mechanism responsible for gastroduodenal lesions in PV possibly involves blood mucosal flow and trophism. The higher susceptibility of H. pylori infection and the high frequency of asymptomatic gastroduodenal lesions in PV patients suggest a surveillance of these patients.