Is there a difference in risk factors for single and multiple symptomatic lesions in small vessel disease?

Inflammation and cerebral small vessel disease: A systematic review

Inflammation is increasingly implicated as a risk factor for dementia, stroke, and small vessel disease (SVD). However, the underlying mechanisms and causative pathways remain unclear. We systematically reviewed the existing literature on the associations between markers of inflammation and SVD (i.e., white matter hyperintensities (WMH), lacunes, enlarged perivascular spaces (EPVS), cerebral microbleeds (CMB)) in cohorts of older people with good health, cerebrovascular disease, or cognitive impairment. Based on distinctions made in the literature, markers of inflammation were classified as systemic inflammation (e.g. C-reactive protein, interleukin-6, fibrinogen) or vascular inflammation/endothelial dysfunction (e.g. homocysteine, von Willebrand factor, Lp-PLA2). Evidence from 82 articles revealed relatively robust associations between SVD and markers of vascular inflammation, especially amongst stroke patients, suggesting that alterations to the endothelium and blood-brain barrier may be a driving force behind SVD. Conversely, cross-sectional findings on systemic inflammation were mixed, although longitudinal investigations demonstrated that elevated levels of systemic inflammatory markers at baseline predicted subsequent SVD severity and progression. Importantly, regional analysis revealed that systemic and vascular inflammation were differentially related to two distinct forms of SVD. Specifically, markers of vascular inflammation tended to be associated with SVD in areas typical of hypertensive arteriopathy (e.g., basal ganglia), while systemic inflammation appeared to be involved in CAA-related vascular damage (e.g., centrum semiovale). Nonetheless, there is insufficient data to establish whether inflammation is causal of, or secondary to, SVD. Findings have important implications on interventions, suggesting the potential utility of treatments targeting the brain endothelium and blood brain barrier to combat SVD and associated neurodegenerative diseases.

Vascular Risk Factor Profiles Differ Between Magnetic Resonance Imaging-Defined Subtypes of Younger-Onset Lacunar Stroke

BACKGROUND AND PURPOSE

Differing associations of vascular risk factors with lacunar infarct have been reported, which is likely because of diagnostic differences and possible heterogeneity in the pathogenesis underlying lacunar infarction. In a large magnetic resonance imaging-verified cohort of lacunar infarct patients, we investigated the risk factor profile of lacunar infarction and magnetic resonance imaging characteristics.

METHODS

One thousand twenty-three patients with lacunar infarction (mean age, 56.7; SD, 8.5) were recruited from 72 stroke centers throughout the United Kingdom as part of the UK Young Lacunar Stroke DNA Study. Risk factor profiles were compared with 1961 stroke-free population controls with similar age. Furthermore, we tested risk factor profiles of lacunar stroke patients for association with the presence of multiple lacunar infarcts, white matter hyperintensities (WMH), and location of the acute lacunar infarct.

RESULTS

Hypertension (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.85-2.64), diabetes mellitus (OR, 2.10; 95% CI, 1.61-2.73), hyperlipidemia (OR, 1.74; 95% CI, 1.46-2.07), and smoking (OR, 1.65; 95% CI, 1.39-1.96) were independently associated in lacunar infarct patients compared with healthy controls. Patients with multiple lacunar infarcts were more likely to be men (OR, 2.53; 95% CI, 1.81-3.53) and have hypertension (OR, 1.54; 95% CI, 1.12-2.04) compared with patients with a single lacunar infarct, independent of other vascular risk factors. The presence of moderate-to-severe WMH versus no or mild WMH was independently associated with increased age (OR, 1.54; 95% CI, 1.12-2.04), hypertension (OR, 2.06; 95% CI, 1.44-2.95), and impaired renal function (OR, 0.90; 95% CI, 0.82-0.98).

CONCLUSIONS

In this magnetic resonance imaging-verified lacunar stroke population, we identified a distinct risk factor profile in the group as a whole. However, there were differing risk factor profiles according to the presence of multiple lacunar infarcts and confluent WMH. The association of hypertension, smoking, and renal impairment with the presence of multiple lacunar infarcts and confluent WMH might reflect a diffuse small vessel arteriopathy.

Comparison of Risk Factor between Lacunar Stroke and Large Artery Atherosclerosis Stroke: A Cross-Sectional Study in China

Background

Stroke is the second most common cause of mortality in China. Although most subtypes of ischemic stroke share similar risk factors, they have different etiologies. Our study aimed to evaluate the different risk factor profiles between the stroke subtypes, lacunar infarcts (LI) and large-artery atherosclerosis (LAA), and clarify the characteristics of current acute ischemic stroke in China.

Methods

In this cross-sectional study, we analyzed the clinical characteristics of 1982 patients with acute ischemic stroke who were admitted to the neurology department at the Peking University First Hospital between 2007 and 2014. Ischemic stroke was further classified into LAA, LI, cardioembolism (CE) and undetermined causes of infarction (UDI) according to TOAST classification. Demographic characteristics, risk factors, as well as the findings of laboratory and imaging tests of 1773 patients with LAA and LI, were analyzed by univariate and multivariate logistic analysis.

Results

Of the 1982 ischemic stroke patients included in this study, 1207 were diagnosed with LAA, 566 with LI, 173 with cardioembolism (CE) and 36 with undetermined causes of infarction (UDI). By comparing the risk factors in multivariate logistic regression analysis, hypertension [odds ratio (OR) = 1.832] and white matter leukoaraiosis (WML) (OR = 1.865) were found to be more strongly correlated with LI than LAA. Low density lipoprotein- cholesterol (LDL-c) (OR = 0.774) were more strongly related to LAA than LI.

Conclusions

This study found that hypertension and WML were more strongly correlated with LI than LAA. LDL-c was more strongly related to LAA than LI.

[Antiphospholipid syndrome in neurology]

Antiphospholipid syndrome (APS) is an autoimmune disease with recurrent thromboses and pregnancy complications (90% are female patients) that can be primary and secondary (with concomitant autoimmune disease). Antiphospholipid antibodies are prothrombotic but also act directly with brain tissue. One clinical and one laboratory criterion is necessary for the diagnosis of APS. Positive serological tests have to be confirmed after at least 12 weeks. Clinical picture consists of thromboses in many organs and spontaneous miscarriages, sometimes thrombocytopaenia and haemolytic anaemia, but neurological cases are the most frequent: headaches, stroke, encephalopathy, seizures, visual disturbances, Sneddon syndrome, dementia, vertigo, chorea, balism, transitory global amnesia, psychosis, transversal myelopathy and Guillain-Barre syndrome. About 50% of strokes below 50 years of age are caused by APS. The first line of therapy in stroke is anticoagulation: intravenous heparin or low-weight heparins. In chronic treatment, oral anticoagulation and antiplatelet therapy are used, warfarin and aspirin, mostly for life. In resistant cases, corticosteroids, intravenous immunoglobulins and plasmapheresis are necessary. Prognosis is good in most patients but some are treatment-resistant with recurrent thrombotic events and eventually death.

[Pharmacotherapy of dementia]

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Association of plasma homocysteine concentration with cerebral white matter hyperintensity on magnetic resonance images in stroke patients

BACKGROUND

Homocysteine (Hcy) has been recognized as a risk factor for atherosclerosis. White matter hyperintensity (WMH) on MRI has been regarded as a hallmark for cerebral small vascular disease. The study is to investigate the relationship between plasma Hcy level and WMH on a hospital-based cohort of Taiwanese stroke patients.

METHODS AND RESULTS

A total of 352 consecutive stroke patients (64.7+/-11.2 years) were included. Severity of WMH was semi-quantitatively evaluated with a scoring system. The top WMH score tertile was defined as severe white matter change (sv-WMH). Associations between Hcy tertile levels and sv-WMH were examined, adjusting for demographics and atherosclerosis risk factors. Subjects in the top Hcy tertile (>10.25 micromol/L) had higher WMH scores and prevalence of sv-WMH than those in the middle and in the bottom tertile. The adjusted odds ratio of having sv-WMH was 2.04 (95% confidence interval 1.20-3.47, p=0.008) for the top Hcy level tertile than for the lower two tertiles combined.

CONCLUSION

Hcy is a risk factor for cerebral white matter lesion in stroke patients. Even mild hyperhomocysteinemia can significantly increase severity of cerebral microangiopathy.

[Dementia and diabetes mellitus]

Dementia and Diabetes mellitus (DM) are major health problems nowadays. DM leads to a significant cognitive decline and increases the risk of dementia, mostly Alzheimer's Disease (AD) and vascular dementia (VaD) by 50-100% and 100-150%, respectively. Amyloid beta (Abeta), the main pathogenic factor in AD development, is eliminated by advanced glycation end products (AGEs) and degraded by insulin degrading enzyme (IDE) for which it competes with insulin. Insulin stimulates secretion of Abeta and promotes brain inflammation. DM I and II cause slowing down of mental speed, lowering of mental flexibility and DM II learning and memory disturbances. DM acts both directly by hyperglycaemia and hyperinsulinaemia and by the blood vessel changes. Hyperglycaemia changes synapse plasticity and leads to cognitive decline. AGEs disrupt the neuron function and bonding to Abeta increases its aggregability. Glycation of tau protein promotes production of neurofibrillary tangles (NFT), the main intracellular pathogenic factor in AD. AGE 2 in DM causes pathological angiogenesis and apoptosis of neurons. AGE receptor (RAGE) is also the specific Abeta receptor with which it produces reactive oxygen species that has, as a result, disruption of mitochondrial function and reduction of neuronal energy resources. Insulinoresistance is linked with the dysexecutive syndrome, and hyperinsulinaemia increases the risk of AD especially by enhancing phosphorylation oftau protein and formation of NFT. Application of insulin showed improvement of memory, behaviour and affect in AD patients. Good glycoregulation emerged as an important factor in dementia prevention, and a better insight in relations of DM and brain function will lead to new potential dementia therapies.

Risk factor profile of cerebral small vessel disease and its subtypes

BACKGROUND

The mechanisms of cerebral small vessel disease (SVD) are unclear. Both atherosclerosis and a non-atherosclerotic diffuse arteriopathy have been reported pathologically. Two pathological and radiological subtypes have been suggested: localised atherosclerotic disease in larger perforating arteries causing larger lacunar infarcts without leukoaraiosis, and diffuse disease in smaller arterioles causing multiple smaller lacunar infarcts with leukoaraiosis. If atherosclerosis were important in SVD as a whole or in one particular subtype, one would expect the risk factor profile to be similar to that of cerebral large vessel disease (LVD).

METHODS

Risk factor profiles were compared in Caucasian stroke patients with SVD (n = 414), LVD (n = 471) and 734 stroke-free Caucasian population controls. Patients with SVD were subdivided according to the presence or absence of confluent leukoaraiosis, into isolated lacunar infarction (ILI) and ischaemic leukoaraiosis (ILA).

RESULTS

Hypertension was commoner in SVD than LVD (odds ratio (OR) 3.43 (2.32 to 5.07); p<0.001) whereas hypercholesterolaemia (OR 0.34 (0.24 to 0.48); p<0.001), smoking (OR 0.63 (0.44 to 0.91); p = 0.012), myocardial infarction (OR 0.35 (0.20 to 0.59); p<0.001) and peripheral vascular disease (OR 0.32 (0.20 to 0.50); p<0.001) were commoner in LVD. Among SVD patients, age (OR 1.11 (1.09 to 1.14); p<0.001) and hypertension (OR 3.32 (1.56 to 7.07); p = 0.002) were associated with ILA and hypercholesterolaemia (OR 0.45 (0.28 to 0.74); p = 0.002), diabetes (OR 0.42 (0.21 to 0.84); p = 0.014) and myocardial infarction (OR 0.18 (0.06 to 0.52); p = 0.001) with ILI.

CONCLUSION

SVD has a different risk factor profile from the typical atherosclerotic profile found in LVD, with hypertension being important. There are differences in the risk factor profile between the SVD subtypes; the association of ILI with hypercholesterolaemia, diabetes and myocardial infarction may be consistent with a more atherosclerotic aetiology.

Pathogenesis of Alzheimer disease

<zakljucak> Alchajmerova bolest javlja se kod 50-60% svih dementnih osoba i predstavlja znacajan zdravstveni i socijalni problem. Upoznavanje patogeneze AB je neophodno u nalazenju terapija koje bi ublazile i modifikovale bolest. Najvise dokaza ima za hipotezu o amiloidnoj kaskadi. Osnovna patohistoloska promena u mozgu obolelih su nakupine amiloida beta (A beta), senilni ili amiloidni pakovi. Ukupni efekat je gubitak sinapsi i neurona. Amiloid se nakuplja i u zidovima krvnih sudova remeteci mozdanu cirkulaciju. Usled navedenih promena nastaje poremecaj neurotransmisije, narocito acetilholina i glutamata i smetnje pamcenja i drugih neuroloskih funkcija. Patogenetski zasnovana terapija se usmerava na aktivaciju alfa sekretaze, inhibiciji beta i gama sekretaza, pojacano uklanjanje A beta, suzbijanje oksidativnog stresa i inflamacije, imunoterapiju upravljenu protiv Abeta i druge mehanizme. U upotrebi su inhibitori ACh-esteraze i antagonista glutamatnih receptora. U prevenciji su dokazani efekti ogranicenog unosa kalorija, Mediteranske dijete i redovne umerene fizicke aktivnosti.