Clinical study of lacunar infarcts in non-hypertensive patients

Endothelial cells as key players in cerebral small vessel disease

Cerebral small vessel disease (SVD) is a vascular disorder that increases the risk of stroke and dementia and is diagnosed through brain MRI. Current primary prevention and secondary treatment of SVD are focused on lifestyle interventions and vascular risk factor control, including blood pressure reduction. However, these interventions have limited effects, a proportion of individuals with sporadic SVD do not have hypertension, and SVD shows strong familial and genetic underpinnings. Here, we describe the increasing evidence that cerebral endothelial cell dysfunction is a key mechanism of SVD. Dysfunctional endothelial cells can cause cerebral blood vessel dysfunction, alter blood-brain barrier integrity and interfere with cell-cell interactions in the neuro-glial-vascular unit, thereby causing damage to adjacent brain tissue. Endothelial cells in SVD may become dysfunctional through intrinsic mechanisms via genetic vulnerability to SVD and/or via extrinsic factors such as hypertension, smoking and diabetes. Drugs that act on endothelial pathways are already looking promising in clinical trials, and understanding their action on endothelial cells and the surrounding brain may lead to the development of other therapies to limit disease progression and improve outcomes for individuals with SVD.

The Potential Impact of Neuroimaging and Translational Research on the Clinical Management of Lacunar Stroke

Lacunar infarcts represent one of the most frequent subtypes of ischemic strokes and may represent the first recognizable manifestation of a progressive disease of the small perforating arteries, capillaries, and venules of the brain, defined as cerebral small vessel disease. The pathophysiological mechanisms leading to a perforating artery occlusion are multiple and still not completely defined, due to spatial resolution issues in neuroimaging, sparsity of pathological studies, and lack of valid experimental models. Recent advances in the endovascular treatment of large vessel occlusion may have diverted attention from the management of patients with small vessel occlusions, often excluded from clinical trials of acute therapy and secondary prevention. However, patients with a lacunar stroke benefit from early diagnosis, reperfusion therapy, and secondary prevention measures. In addition, there are new developments in the knowledge of this entity that suggest potential benefits of thrombolysis in an extended time window in selected patients, as well as novel therapeutic approaches targeting different pathophysiological mechanisms involved in small vessel disease. This review offers a comprehensive update in lacunar stroke pathophysiology and clinical perspective for managing lacunar strokes, in light of the latest insights from imaging and translational studies.

Increased risk of cognitive impairment and more severe brain lesions in hypertensive compared to non-hypertensive patients with cerebral small vessel disease

Although cerebral small vessel disease (SVD) is traditionally associated with aging and hypertension (HT), there are patients exhibiting sporadic SVD, free of HT. We aimed to investigate the differences in clinical and neuroradiological presentation in SVD patients in reference to the presence of HT as a risk factor (RF). Vascular RF, cognitive and functional status were evaluated in a cohort of 424 patients. Patients were classified in two groups based on the presence of HT. Severity of vascular lesions was assessed using 1.5 T magnetic resonance imaging with Age-Related White Matter Changes scale total score (tARWMC) and Fazekas scale periventricular (PV) and deep subcortical (DS) scores. No difference between groups in age and sex distribution was noted. In univariate analysis, HT was associated with vascular cognitive impairment (vCI) (OR 2.30, 1.53-3.45, P < 0.0001), functional status (OR 1.47, 1.11-1.95, P = 0.007), depression (OR 2.13, 1.23-3.70, P = 0.007), tARWMC (OR 1.10, 1.05-1.16 95% CI, P < 0.0001), Fazekas PV score (OR 1.34, 1.08-1.67 95% CI, P = 0.008), Fazekas DS score (OR 1.95, 1.44-2.63 95% CI, P < 0.0001) and total number of lacunes (OR 1.10, 1.02-1.18 95% CI, P = 0.009). Multivariate logistic regression analysis indicated that HT was an independent RF for vCI (OR 1.74, 1.09-2.76 95% CI, P = 0.020) and higher Fazekas DS score (OR 1.57, 1.11-2.22 95% CI, P = 0.011). The Kaplan-Meier curve of estimates of survival of SVD patients without vCI revealed a higher proportion of patients with HT progressing to vCI over time when compared to HT-free cases. In patients with sporadic SVD, HT is a contributing factor to worse clinical outcomes and neuroradiological presentation.

Diagnosis of CADASIL disease in normotensive and non-diabetics with lacunar infarct

BACKGROUND

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is characterized by recurrent cerebral ischemic episodes of the lacunar subtype usually without traditional vascular risk factors. We investigated the frequency of CADASIL among selected patients with cerebral ischemia of the lacunar subtype.

METHODS

we studied patients under 65 years old who presented cerebral ischemia of the lacunar subtype without hypertension, diabetes mellitus or other causes that explained the cerebral ischemia. On the skin biopsies, we performed immunostaining analysis on 5μm frozen sections with monoclonal antibody anti-Notch 3 (1E4). We also performed a genetic analysis of the Notch 3 gene (exons 3,4,5,6,11 and 19).

RESULTS

of 1.519 patients analyzed, only 57 (3.7%) fulfilled the selection criteria, and 30 of them accepted to participated in the study. We studied 30 patients, mean age was 53 years (range 34 to 65), 50% were men and all patients suffered a lacunar stroke. Immunostaining analysis was positive in two patients (6.6%) and the genetic analysis confirmed a mutation characteristic of CADASIL in exon 4 nt 622C/T (Arg 182 Cys) and 694 T/C (Cys206Arg) respectively.

CONCLUSIONS

CADASIL disease was present in 6.6% of patients younger than 65 years with a lacunar stroke and without hypertension or diabetes mellitus. Screening for CADASIL should be considered in these patients.

Human cerebral neuropathology of Type 2 diabetes mellitus

The cerebral neuropathology of Type 2 diabetes (CNDM2) has not been positively defined. This review includes a description of CNDM2 research from before the 'Pubmed Era'. Recent neuroimaging studies have focused on cerebrovascular and white matter pathology. These and prior studies about cerebrovascular histopathology in diabetes are reviewed. Evidence is also described for and against the link between CNDM2 and Alzheimer's disease pathogenesis. To study this matter directly, we evaluated data from University of Kentucky Alzheimer's Disease Center (UK ADC) patients recruited while non-demented and followed longitudinally. Of patients who had come to autopsy (N = 234), 139 met inclusion criteria. These patients provided the basis for comparing the prevalence of pathological and clinical indices between well-characterized cases with (N = 50) or without (N = 89) the premortem diagnosis of diabetes. In diabetics, cerebrovascular pathology was more frequent and Alzheimer-type pathology was less frequent than in non-diabetics. Finally, a series of photomicrographs demonstrates histopathological features (including clinical-radiographical correlation) observed in brains of persons that died after a history of diabetes. These preliminary, correlative, and descriptive studies may help develop new hypotheses about CNDM2. We conclude that more work should be performed on human material in the context of CNDM2.