Analysis of the lesion distributions and mechanism of acute middle cerebral artery infarctions involving the striatocapsular region

18q21.1q21.32 Deletion in a Patient With Juvenile Cerebral Infarction

The chromosome 18q deletion syndrome is a well-recognized chromosomal aberration characterized by intellectual disability, facial dysmorphism, short stature, microcephaly, cardiac anomalies, such as atrial and ventricular septal defect, and hypotonia; however, the phenotype is highly variable depending on the combination of genes within the chromosomal aberration regions. Thus far, no association was found between 18q deletion and cerebral infarction. Herein, we report a case of 18q deletion syndrome that caused juvenile cerebral infarction. A 32-year-old woman with an intellectual disability and facial dysmorphism presented with sudden-onset left-sided weakness. Brain magnetic resonance imaging revealed a striatocapsular infarction. Abnormalities in thrombotic profiles and embolic sources could not be identified. Microarray-based comparative genomic hybridization analysis detected a microdeletion in chromosome 18 encompassing the cytoregion 18q21.1q21.32. The deletion region contains the TCF4 and SMAD4 genes, whose haploinsufficiency causes the causative genes of Pitt-Hopkins syndrome (PTHS) and juvenile polyposis/hereditary hemorrhagic telangiectasia (JPHT or JPHHT), respectively. The patient's facial features were characteristic of PTHS, including a broad, beaked nasal bridge and a wide mouth with a bow-shaped upper lip. On the contrary, the patient did not show breathing abnormalities, which is one of the hallmarks of PTHS. We could not elucidate the relationship between cerebral infarction and genes included in the deleted region of 18q. However, if patients with chromosomal aberrations have cerebral infarctions, investigating the genes included within the chromosomal aberration regions may increase our knowledge of the genes involved in juvenile cerebral infarction.

An endovascular canine stroke model: middle cerebral artery occlusion with autologous clots followed by ipsilateral internal carotid artery blockade

Stroke is one of the leading causes of death worldwide and the main reason for long-term disability. An appropriate animal model of stroke is urgently required for understanding the exact pathophysiological mechanism of stroke and testing any new therapeutic regimen. Our work aimed to establish a canine stroke model occluding the middle cerebral artery (MCA) and blocking the ipsilateral internal carotid artery (ICA), and to assess the infarct lesions by magnetic resonance imaging. The stroke model was generated by injecting two autologous clots into each MCA, followed by 2-h ipsilateral ICA blockade (ilICAB) using a catheter in 15 healthy adult beagles. Outcome measurements included 24-h and 7-day postocclusion T2-weighted imaging (T2WI)-based infarct volume calculation. In addition, pial collateral score, canine neurobehavioral score and histopathologic results were documented. Out of 15 dogs, 12 with successful MCA occlusion (MCAO) and ilICAB survived 7 days without complications or casualties and MCA were reperfused at 7 days after occlusion. High signal intensity in the basal ganglia and cerebral cortex on T2WI was initially observed in each dog at 6 h after the procedure. The mean percentage hemispherical infarct volume corrected for edema in all dogs on T2WI at 24 h after occlusion was 12.99±1.57%, and the degree of variability was 12.08%. The infarct volumes at 24 h after occlusion correlated with pial collateral scores and canine neurobehavioral scores well. This canine stroke model with combined MCAO and ilICAB reported here were proven to be highly feasible and reproducible.

A novel embolic stroke model resembling lacunar infarction following proximal middle cerebral artery occlusion in beagle dogs

It is estimated that lacunar infarcts account for 25% of all ischemic strokes, but its exact etiology is still on debating. The existing controversies include whether the embolisms can indeed cause lacunar stroke in humans or animal models. We hypothesized that lacunar infarction can be induced by the proximal middle cerebral artery (MCA) segmental occlusion involving the orifices of lenticulostriate arteries in animal models, which have abundant distal cerebral collateral anastomosis. Our work here establishes a proximal MCA occlusion model using thrombi (autologous blood clots about 1.7 mm in diameter and 5 mm in length) in 8 beagle dogs, evaluates the progression of ischemic lesions at 30 min interval within 6 h after embolization using the diffusion weighted imaging (DWI), and discusses the potential mechanisms of lacunar infarction. Our results indicate that the left proximal MCAs can be successfully occluded in all dogs using interventional single-thrombus method. The small solitary or multiple ischemic lesions shown in DWI were observed in the deep brain area, with the mean detecting time of 1.21 ± 0.45 h using DWI and diameter of 6.62 ± 0.60mm in 6h-DWI after procedure. In conclusion, our method established an ischemic model which can recapitulate the radiologic and histologic changes in lacunar infarcts, suggesting that emboli can cause lacunar infarcts in animal model.