Alternative Splicing of FOXP3 Controls Regulatory T Cell Effector Functions and Is Associated With Human Atherosclerotic Plaque Stability.

RATIONALE: Regulatory T (Treg) cells suppress immune responses and have been shown to attenuate atherosclerosis. The Treg cell lineage-specification factor FOXP3 (forkhead box P3) is essential for Treg cells' ability to uphold immunologic tolerance. In humans, FOXP3 exists in several different isoforms, however, their specific role is poorly understood. OBJECTIVE: To define the regulation and functions of the 2 major FOXP3 isoforms, FOXP3fl and FOXP3Δ2, as well as to establish whether their expression is associated with the ischemic atherosclerotic disease. METHODS AND RESULTS: Human primary T cells were transduced with lentiviruses encoding distinct FOXP3 isoforms. The phenotype and function of these cells were analyzed by flow cytometry, in vitro suppression assays and RNA-sequencing. We also assessed the effect of activation on Treg cells isolated from healthy volunteers. Treg cell activation resulted in increased FOXP3 expression that predominantly was made up of FOXP3Δ2. FOXP3Δ2 induced specific transcription of GARP (glycoprotein A repetitions predominant), which functions by tethering the immunosuppressive cytokine TGF (transforming growth factor)-ß to the cell membrane of activated Treg cells. Real-time polymerase chain reaction was used to determine the impact of alternative splicing of FOXP3 in relation with atherosclerotic plaque stability in a cohort of >150 patients that underwent carotid endarterectomy. Plaque instability was associated with a lower FOXP3Δ2 transcript usage, when comparing plaques from patients without symptoms and patients with the occurrence of recent (<1 month) vascular symptoms including minor stroke, transient ischemic attack, or amaurosis fugax. No difference was detected in total levels of FOXP3 mRNA between these 2 groups. CONCLUSIONS: These results suggest that activated Treg cells suppress the atherosclerotic disease process and that FOXP3Δ2 controls a transcriptional program that acts protectively in human atherosclerotic plaques.

Atypical erythrocytes and platelets in a patient with a pro-thrombin mutation.

Prothrombin mutation G20210A, anti-phospholipid syndrome as well as iron overload has previously been shown to cause thrombotic events. The main reason for this is the involvement of these anomalies in causing hypercoagulability of the coagulation system, which frequently leads to venous and arterial thrombotic events. We report the case of a 37-year-old white female with prothrombin mutation G20210A, anti-phospholipid syndrome, as well as an increased serum ferritin level, who experienced two transient ischemic attacks and suffers from regular amaurosis fugax. We present an ultrastructural depiction of erythrocytes, platelets, and the fibrin network, to explain the clinical manifestations of the thrombotic state seen in this patient.

Internal jugular venous abnormalities in transient monocular blindness.

BACKGROUND: The etiology of transient monocular blindness (TMB) in patients without carotid stenosis has been linked to ocular venous hypertension, for their increased retrobulbar vascular resistance, sustained retinal venule dilatation and higher frequency of jugular venous reflux (JVR). This study aimed to elucidate whether there are anatomical abnormalities at internal jugular vein (IJV) in TMB patients that would contribute to impaired cerebral venous drainage and consequent ocular venous hypertension. METHODS: Contrast-enhanced axial T1-weighted magnetic resonance imaging (MRI) was performed in 23 TMB patients who had no carotid stenosis and 23 age- and sex-matched controls. The veins were assessed at the upper IJV (at C1-3 level) and the middle IJV (at C3-5 level). Grading of IJV compression/stenosis was determined bilaterally as follows: 0 = normal round or ovoid appearance; 1 = mild flattening; 2 = moderate flattening; and 3 = severe flattening or not visualized. RESULTS: There was significantly more moderate or severe IJV compression/stenosis in the TMB patients at the left upper IJV level and the bilateral middle IJV level. Defining venous compression/stenosis scores ≥ 2 as a significant cerebral venous outflow impairment, TMB patients were found to have higher frequency of significant venous outflow impairment at the upper IJV level (56.5% vs. 8.7%, p = 0.0005) and the middle IJV level (69.6% vs. 21.7%, p=0.0011). CONCLUSIONS: TMB Patients with the absence of carotid stenosis had higher frequency and greater severity of IJV compression/stenosis which could impair cerebral venous outflow. Our results provide evidence supporting that the cerebral venous outflow abnormality is one of the etiologies of TMB.

Embolic and nonembolic transient monocular visual field loss: a clinicopathologic review.

Transient monocular blindness and amaurosis fugax are umbrella terms describing a range of patterns of transient monocular visual field loss (TMVL). The incidence rises from ≈1.5/100,000 in the third decade of life to ≈32/100,000 in the seventh decade of life. We review the vascular supply of the retina that provides an anatomical basis for the types of TMVL and discuss the importance of collaterals between the external and internal carotid artery territories and related blood flow phenomena. Next, we address the semiology of TMVL, focusing on onset, pattern, trigger factors, duration, recovery, frequency-associated features such as headaches, and on tests that help with the important differential between embolic and non-embolic etiologies.

Amaurosis fugax caused by heritable thrombophilia-hypofibrinolysis in cases without carotid atherosclerosis: thromboprophylaxis prevents subsequent transient monocular partial blindness.

Nineteen patients (age 60 +/- 14) with amaurosis fugax associated with heritable thrombophilia-hypofibrinolysis without ipsilateral atherosclerotic carotid plaque or other causes of amaurosis fugax were studied. Our hypothesis was that case-specific thromboprophylaxis would prevent subsequent amaurosis fugax episodes. Prospective treatment data were available for 13 cases. Thrombophilic disorders included high Factors VIII and XI, G20210A prothrombin heterozygosity, low proteins C and S, MTHFR mutations, and the PL A1/A2 mutation. Hypofibrinolytic disorders included plasminogen activator inhibitor-1 4G4G, and high lipoprotein (a). Treatments included Coumadin; Lovenox, folic acid-vitamin B6-vitamin B12, discontinuation of estrogens-selective estrogen receptor modulators, Glucophage, and aspirin, as appropriate. Usually within 1 month on therapy, patients became asymptomatic and have remained asymptomatic for > or = 1 year on therapy, without adverse treatment side effects. When amaurosis fugax occurs without carotid artery atherosclerosis or other known causes, thrombophilia or hypofibrinolysis, or both are nearly universal, safely treatable, reversible pathoetiologies.

Transient visual loss triggered by scuba diving in a patient with a petrous epidermoid and combined thrombotic risk factors.

A 25-year-old woman who developed transient neurological abnormalities after scuba diving is reported. The subsequent day she experienced transient left-side monocular blindness. Arterial ocular occlusion in apparently healthy young women is unusual, and a search for the cause of this devastating vascular event is mandatory. Occlusion of the left branch retinal artery, total occlusion of the left internal carotid artery, and a petrous apex epidermoid were found, together with a shortened prothrombin time (INR: 0.73), a slightly elevated serum cholesterol level (6.1 mmol/l) and combined thrombophilia (elevated FVIIIC plus type 2 sticky platelet syndrome). This case underlines the complex mechanism of thromboembolic diseases, and the importance of the acquired trigger (in the present case scuba diving) in addition to the long-term anatomical and biochemical risk factors.

Distribution of carotid arterial lesions in Chinese patients with transient monocular blindness.

BACKGROUND AND PURPOSE: Asian patients with cerebrovascular diseases have more intracranial atherosclerosis and less extracranial carotid artery stenosis compared with white patients. We systemically evaluated the distribution of carotid arterial lesions in Chinese patients with transient monocular blindness (TMB), which was rarely reported. METHODS: We prospectively evaluated 105 consecutive patients with TMB. All of the patients received ocular and physical examinations, blood tests for coagulation function and autoimmune diseases, and ultrasonography of cervical and intracranial arteries. All of the carotid lesions were confirmed by magnetic resonance angiography or cerebral angiography. RESULTS: Of the 36 (34.3%) patients with significant carotid stenosis (> or =50%), 16 (15.2%) had extracranial carotid stenosis; 17 (16.2%) had carotid siphon stenosis; and 3 (2.9%) had both. The duration, onset, and patterns of visual loss were not different between patients with and without carotid arterial lesion. CONCLUSIONS: This study signified the importance of carotid siphon stenosis as a probable underlying etiology for TMB in Chinese patients.

Retinal and optic nerve degeneration after chronic carotid ligation: time course and role of light exposure.

BACKGROUND AND PURPOSE: Carotid artery disease can cause chronic retinal ischemia, resulting in transient or permanent blindness, pupillary reflex dysfunction, and retinal degeneration. This experiment investigated the effects of chronic retinal ischemia in an animal model involving permanent carotid occlusion. The time course of retinal pathology and the role of light in this pathology were examined. METHODS: Sprague-Dawley rats underwent permanent bilateral occlusion of the common carotid arteries or sham surgery. Half of the animals were postsurgically housed in darkness, and half were housed in a 12-hour light/dark cycle. Animals were killed at 3, 15, and 90 days after surgery. Stereological techniques were used to count the cells of the retinal ganglion cell layer. Thy-1 immunoreactivity was assessed to specifically quantify loss of retinal ganglion cells. The thicknesses of the remaining retinal sublayers were measured. Optic nerve degeneration was quantified with the Gallyas silver staining technique. RESULTS: Permanent bilateral occlusion of the common carotid arteries resulted in loss of the pupillary reflex to light in 58% of rats. Eyes that lost the reflex showed (1) optic nerve degeneration at 3, 15, and 90 days after surgery; (2) a reduction of retinal ganglion cell layer neurons and Thy-1 immunoreactivity by 15 and 90 days; and (3) a severe loss of photoreceptors by 90 days when postsurgically housed in the light condition only. CONCLUSIONS: Ischemic damage to the optic nerve caused loss of pupillary reflex and death of retinal ganglion cells in a subset of rats. Subsequently, light toxicity induced death of the photoreceptors.

Patterns of cerebrovascular symptomatology associated with carotid atheroma.

The aim of this study was to identify ultrasonic tissue characteristics and stenosis of carotid plaques that correspond to amaurosis fugax, hemispheric transient ischaemic attack, and stroke. At total of 146 symptomatic carotid plaques (136 patients) associated with amaurosis fugax, hemispheric transient ischaemic attack, stroke, and having 50-99% stenosis on duplex, were studied. These plaques were imaged on duplex, captured in a computer and their grey scale median was evaluated to distinguish the dark (low grey scale median) from the bright (high grey scale median) plaques. Stenosis was assessed on duplex. The amaurosis fugax group corresponded to carotid plaques with low grey scale median and severe stenosis, as contrasted with the other two groups (hemispheric transient ischaemic attack and stroke) (P < 0.05). These results suggested that amaurosis fugax was dependent only on the instability of carotid plaques, whereas hemispheric transient ischaemic attack and stroke were both dependent on carotid plaques and other pathogenetic factors.

Carotid plaque gross morphology and clinical presentation: a prospective study of 457 carotid artery specimens.

BACKGROUND AND PURPOSE: In carotid artery disease, the relationship between carotid plaque morphology and the patient's neurologic symptoms is reportedly conflicting. The aim of this study was to correlate gross carotid plaque characteristics with the presenting symptoms in a relatively large series of patients who underwent carotid endarterectomy (CEA). METHODS: Four hundred and five patients who underwent 461 CEAs were divided into three groups: (1) transiently symptomatic [transient ischemic attack (TIA) or amaurosis fugax]; (2) prior stroke; and (3) asymptomatic. The degree of stenosis based on the preoperative angiograms was used in association with the presenting symptoms as the primary criterion in the decision to operate. Carotid plaque characteristics, including ulcerated plaque (UP), intraplaque hemorrhage (IH), uncomplicated plaque, and degree of stenosis, were recorded prospectively for 457 CEAs, since 4 CEAs were excluded from the study. All CEA specimens were grossly evaluated at surgery. RESULTS: There was a statistically higher incidence of UP in transiently symptomatic (P = 0.008) or prior stroke (P = 0.006) patients than in the asymptomatic group. When IH was considered independently, its incidence did not differ significantly between the three groups. Previously symptomatic patients tended to have higher-grade stenosis than asymptomatic patients, although the difference failed to reach statistical significance (P = 0.06). Although the incidences of UP and IH were higher in the higher-grade stenosis group, the difference was again not significant. CONCLUSIONS: Carotid UP correlates closely with an initial presentation of TIA, amaurosis fugax, or prior stroke, while the association between IH and presenting symptoms is less clear. Although there is an insignificant trend toward a correlation between the higher degrees of stenosis and the onset of transient symptoms, the degree of stenosis appears unaffected by the morphology of the plaque. These findings suggest that plaque morphology may play an important role in the presentation of carotid artery disease.

Plaque morphology correlates with cerebrovascular symptoms in patients with complex aortic arch plaque.

BACKGROUND: Studies of aortic arch plaques with transesophageal echocardiography have demonstrated that complex aortic arch plaques (CAPs) greater than or equal to 4 mm in thickness are associated with ischemic stroke. Recent studies have demonstrated that the morphological features of plaques may aid in the identification of aortic plaques that are more likely to be associated with embolic stroke. OBJECTIVE: To identify aortic plaques that are more likely to be associated with embolic stroke by means of their morphological features. METHODS: Transcutaneous B-mode ultrasonography was used to image aortic arch plaques in 500 consecutive patients. The criteria used to identify the morphological features of carotid artery plaques that are more likely to be associated with ischemic stroke (heterogeneous rather than homogeneous) were applied to aortic arch plaques. Statistical comparisons were made using the Fisher exact test. RESULTS: Ischemic symptoms (eg, stroke, transient ischemic attack, and amaurosis fugax) were present in 38% of 104 patients with CAP and in 34% of 391 patients without CAP. Nineteen (51%) of 37 patients with heterogeneous CAP were symptomatic. Twenty-one (31%) of 67 patients with homogeneous CAP were symptomatic (P = .04). CONCLUSION: Transcutaneous B-mode ultrasonography of the aortic arch can help to identify heterogeneous plaques that are more likely to be associated with ischemic stroke using morphological criteria derived from studies of carotid artery plaque.