[Morphological signs of mitochondrial cytopathy in skeletal muscles and micro-vessel walls in a patient with cerebral artery dissection associated with MELAS syndrome].

Skin and muscles biopsy specimens of a patient harboring A3243G mutation in mitochondrial DNA, with dissection of internal carotid and vertebral arteries, associated with MELAS were studied using histochemical and electron-microscopy techniques. Ragged red fibers, regional variability of SDH histochemical reaction, two types of morphologically atypical mitochondria and their aggregation were found in muscle. There was correlation between SDH histochemical staining and number of mitochondria revealed by electron microscopy in muscle tissue. Similar mitochondrial abnormality, their distribution and cell lesions followed by extra-cellular matrix mineralization were found in the blood vessel walls. In line with generalization of cytopathy process caused by gene mutation it can be supposed that changes found in skin and muscle microvessels also exist in large cerebral vessels causing the vessel wall "weakness", predisposing them to dissection.

[Ultrastructural changes of skin arteries in patients with spontaneous cerebral artery dissection].

Spontaneous cerebral artery dissection is a common cause of ischemic stroke in young adults and children. Dissection is often related to arterial wall weakness the cause of which is unknown. An aim of the present paper was to carry out an electron microscopic study of skin arteries and arterioles in patients with ischemic stroke caused by cerebral artery dissection. Skin biopsy samples from 3 patients (2 men and one women, 15, 25 and 43 years of age, respectively) were studied. Electron microscopy revealed changes of endothelial, smooth muscle cells and fibroblasts in the skin microvessels. These changes included the decrease in the number of mitochondria and their alterations (vacuolization, destruction of the cristae, the presence of the needle-shaped crystals and crystal-like inclusions) and swelling of the endoplasmic reticulum. Some of these changes were characteristic of mitochondrial diseases. The changes in the extracellular matrix (thickening of the subendothelial layer and deposition of microcalcificats) were also detected. It is assumed that the mitochondrial cytopathy found in the skin microvessels may be also present in large cerebral arteries. This could underlie dysplastic changes in the cerebral artery wall and predispose to its dissection.

[Results of proximal vertebral arteries endovascular interventions].

OBJECTIVE: To evaluate immediate and long-term clinical and ultrasound efficacy of proximal vertebral arteries stenting. We studied 74 subjects (age 61+/-10 years) who underwent transluminal balloon angioplasty with stenting of vertebral arteries (77 vessels). Technical success (i.e., residual stenosis < 20%) was achieved in 95% patients. No events (acute stroke, myocardial infarction, or death) were recorded during the procedure or in early postoperative period. Clinical improvement was seen in 81% patients presented with symptoms of vetebrobasilar insufficiency at the baseline (n = 52). Sixty six patients (89%) were followed up in the late postoperative period (6 to 54 months after the intervention). No events of acute stroke were recorded in the vertebrobasilar circulation. Relapse of vertebrobasilar symptoms after temporary improvement was seen in 13% patients. Stent restenosis/occlusion was diagnosed in 36% patients although no relationship was revealed between the alteration of stent patency and relapse of clinical symptoms. Restenosis correlated with initial stenosis of > or = 70% (p < 0.05) and type of stent material. Use of cobalt chromium stents was associated with 2-fold decrease of restenosis rate vs non cobalt chromium stents (24% vs 50%, respectively, p < 0.05). Therefore, stenting of proximal vertebral arteries yields good technical and clinical results. High restenosis rate is a major problem of endovascular treatment of atherosclerosis and needs further evaluation.

[Mitochondrial arteriopathy as a cause of spontaneous dissection of cerebral arteries].

The vascular wall weakness caused by dysplastic alterations predisposes to the spontaneous dissection of cerebral arteries. The authors hypothesized for the first time that dysplasia might be the result of mitochondrial cytopathy. To test this hypothesis, the muscle biopsy was conducted in 3 male patients, aged 30-38 years, with the spontaneous dissection of the internal carotid (2) and posterior cerebral (1) arteries. Clinically dissections manifested by ischemic stroke (2) or the peripheral paresis of the hypoglossal nerve (1). The morphological study of fresh frozen sections of muscle by modified Gomori trichrome method revealed ragged-red fibers The histochemical study showed the severe decrease of the stain on succinate dehydrogenase and cytochrome-c-oxidase as well as the focal intensive staining of peripheral regions of muscle fibers. The complex of found changes is characteristic for a mitochondrial pathology. No patients had A3243G tRNA gene mutation, the most common mutation for MELAS. The serum lactate level was elevated only in one patient. We suggest that the mitochondrial disorder occurs not only in muscle, but also in cerebral artery wall--mitochondrial arteriopathy, which predisposes to spontaneous cerebral artery dissection.

[Spontaneous dissection (intramural hematoma) in vertebrobasilar artery and ischemic stroke].

Twelve patients (mean age 36,0+/-10,4 years) with a vertebral artery dissection (VAD) were followed-up during 2,5 months - 5 years. All patients underwent magnetic resonance (MR) imaging of the head, MR-angiography (11 patients - repeated studies), 5 patients - conventional cerebral angiography. VAD was located on extracranial (7), intracranial (1), extra-intracranial levels (4), the extension of dissection to the basilar artery was found in 2 patients. Dissection involving both vertebral arteries was observed in 6 patients, recurrent VAD after 4-15 months - in 3 patients. A total number of VAD was 22, a total number of cerebrovascular events - 15. The latter included ischemic strokes (13), transient ischemic attacks (1) and isolated headache (1). Ischemic cerebrovascular events were characterized by the combination of cerebral ischemic symptoms with occipital headache and/or posterior neck pain (79%) which usually preceded ischemic cerebral symptoms by the interval of several hours - 3 weeks as well as a goof recovery of neurological deficit (92%). In a half of patients, cerebral ischemic symptoms developed after neck movements or manual therapy. Angiography revealed the stenosis of vertebral arteries, usually elongated, irregular or tapered (64%), more often located at the level of V3-V4 segments, vertebral artery occlusion (36%) and pseudoaneurisms (19%). The repeated angiography performed in 2-3 months or more showed positive changes in 82%, the complete (86%) or partial (14%) resolution of all stenoses and the complete or partial recanalization of the half of vertebral artery occlusions, the regress of all pseudoaneurisms. An intramural hematoma on MR imaging (the axial plane) was found in 85% dissections analyzed, the increased vertebral artery outer diameter - in 69%. Atherosclerotic plaques were absent in all cases. VAD is one of unknown causes of ischemic stroke in vertebrobasilar circulation. Diagnosis is based on characteristic clinical and angiography data.