Early remodeling and loss of light-induced dilation of retinal small arteries in CADASIL

A major hurdle to therapeutic development in cerebral small vessel diseases is the lack of in-vivo method that can be used repeatedly for evaluating directly cerebral microvessels. We hypothesised that Adaptive Optics (AO), which allows resolution images up to 1-2 μm/pixel at retinal level, could provide a biomarker for monitoring vascular changes in CADASIL, a genetic form of such condition. In 98 patients and 35 healthy individuals, the wall to lumen ratio (WLR), outer and inner diameter, wall thickness and wall cross-sectional area were measured in a parapapillary and/or paramacular retinal artery. The ratio of vessel diameters before and after light flicker stimulations was also calculated to measure vasoreactivity (VR). Multivariate mixed-model analysis showed that WLR was increased and associated with a larger wall thickness and smaller internal diameter of retinal arteries in patients. The difference was maximal at the youngest age and gradually reduced with aging. Average VR in patients was less than half of that of controls since the youngest age. Any robust association was found with clinical or imaging manifestations of the disease. Thus, AO enables the detection of early functional or structural vascular alterations in CADASIL but with no obvious link to the clinical or imaging severity.

Do Mean Platelet Volume and Platelet Distribution Width Have An Association with White Matter Hyperintensities in Migraine Patients?

Objective

Increased prevalence of white matter hyperintensities (WMH) is reported in migraine patients; however, the pathophysiology and the progression of these lesions are not definitely clear. Mean platelet volume (MPV) and platelet distribution width (PDW) are easily obtained markers for platelet activity. The aim of this study is to evaluate the relationship between the presence of WMH and MPV and PDW in patients with migraine in order to determine the role of platelet activity in the pathophysiology of WMH.

Methods

Patients who were admitted to the neurology outpatient clinics of Baskent University Hospital from January 2011 to December 2015 with migraine and between 18 and 55 years of age were evaluated retrospectively. The blood samples were taken and total blood count parameters including MPV and PDW were analyzed. Brain magnetic resonance images were evaluated.

Results

Totally, 218 patients were evaluated in this study. Forty-eight (22.0%) patients had WMH in the brain magnetic resonance imaging. In patients with WMH, the median of age was higher than the patients without WMH and the difference was statistically significant (P < 0.05). There was no statistically significant difference between MPV, PDW values, and the presence of WMH.

Conclusions

There are multiple theories suggested for the mechanism of WMH, but the major cause and pathophysiology are still undetermined. Our data suggested that increased platelet activity is insufficient by itself to explain the pathophysiology of WMH in migraine patients and to improve the knowledge on this issue further large longitudinal studies should be performed.

Prevalence and clinical characteristics of white matter hyperintensities in Migraine: A meta-analysis

BACKGROUND

Current evidences show an increased risk of white matter hyperintensities (WMHs) in migraineurs compared to age-matched controls. However, WMHs prevalence and the associations between WMHs and clinical characteristics in migraineurs have not been systematically evaluated using a meta-analytical approach. This study explored the pooled prevalence of WMHs and the associations of WMHs with the clinical characteristics in patients with migraine.

METHODS

A systematic review and meta-analysis of observational studies reporting the occurrence and clinical characteristics of patients with WMHs attributed to migraine was performed. We searched the PubMed, Web of Science, and Embase databases. Random-effects models were used to calculate the pooled prevalence rate, odds ratio (OR), or mean difference (MD) with corresponding 95% confidence intervals (CIs).

RESULTS

Thirty eligible studies were identified including 3,502 migraineurs aged 37.2 (mean) years. The pooled WMHs prevalence was 44 %, 45 %, and 38 % in migraine, migraine with aura, and migraine without aura groups, respectively. In migraineurs with WMHs, the frontal lobe and subcortical white matter were the most susceptible area. Compared with non-migraine controls, patients with migraine had increased odds for WMHs (OR 4.32, 95 % CI = 2.56-7.28, I² = 67 %). According to reported univariable results from included studies, pooled analysis showed that clinical characteristics including age, presence of aura, disease duration, hypertension, diabetes mellitus and right-to-left shunt were associated with the presence of WMHs. Migraine pain and aura characteristics were not related to WMHs.

CONCLUSIONS

These data suggest that WMHs are common in migraine, especially in those who are older or have aura, hypertension, diabetes mellitus, or right-to-left shunt. A better understanding of the WMHs attributed to migraine is needed in future studies.

Choroidal thickness in eyes of migraine patients measured using spectral domain-optical coherence tomography: A meta-analysis

Recent developments in high-resolution optical coherence tomography allow evaluation of even the slightest changes of choroidal thickness in various disorders, including migraine. In this review, we analyze the choroidal thickness measurements reported in various studies that compare results between migraineurs and healthy individuals. We searched PubMed, Scopus, and EMBASE to identify relevant literature reporting choroidal thickness in the migraineurs' different macular regions compared with healthy controls. A fixed-effects or random-effects model was applied for the meta-analysis based on the heterogeneity level. Moreover, subgroup analyses, meta-regression, publication bias, and quality assessment were also performed. We identified ten studies involving 580 migraineurs (173 with aura, 128 without aura, and 279 without specification for the presence of aura) and 407 healthy controls to be included in this meta-analysis. Results indicated that average choroidal thickness was significantly decreased in the migraine cases (SMD, -1.28; 95% CI, -2.47 to -0.08; P = 0.04) compared to healthy individuals. Furthermore, both with aura (SMD, -1.16; 95% CI, -1.39 to -0.92; P < 0.0001) and without aura migraine patients (SMD, -0.81; 95% CI, -1.28 to -0.34; P < 0.001) had significantly thinner subfoveal choroid compared to healthy controls. Moreover, subfoveal choroidal thickness in the migraineurs with aura was significantly lower than those without aura (SMD, -0.45; 95% CI, -0.84 to -0.05; P = 0.03). The alterations in choroidal thickness, suggestive of migraine's neurovascular pathophysiology, were tentatively confirmed by this study's findings. Further longitudinal studies with more diverse settings are required to derive more definitive conclusions.

Retinal thickness changes in different subfields reflect the volume change of cerebral white matter hyperintensity

Purpose

To investigate the relationship between the retinal thickness in different subfields and the volume of white matter hyperintensity (WMH), with the hope to provide new evidence for the potential association between the retina and the brain.

Methods

A total of 185 participants aged over 40 years were included in our study. Magnetic resonance imaging (MRI) was used to image the WMH, and WMH volume was quantitatively measured by a specific toolbox. The thickness of the total retina, the retinal nerve fiber layer (RNFL), and the ganglion cell and inner plexiform layer (GCIP) was measured by optical coherence tomography (OCT) in nine subfields. The association between retinal thickness and WMH volume was demonstrated using binary logistic regression and Pearson correlation analysis.

Results

Participants were divided into two groups by the WMH volume (‰, standardized WMH volume) median. In the quartile-stratified binary logistic regression analysis, we found that the risk of higher WMH volume showed a positive linear trend correlation with the thickness of total retina (95% CI: 0.848 to 7.034; P for trend = 0.044)/ GCIP (95% CI: 1.263 to 10.549; P for trend = 0.038) at the central fovea, and a negative linear trend correlation with the thickness of nasal inner RNFL (95% CI: 0.086 to 0.787; P for trend = 0.012), nasal outer RNFL (95% CI: 0.058 to 0.561; P for trend = 0.004), and inferior outer RNFL (95% CI: 0.081 to 0.667; P for trend = 0.004), after adjusting for possible confounders. Correlation analysis results showed that WMH volume had a significant negative correlation with superior outer RNFL thickness (r = −0.171, P = 0.02) and nasal outer RNFL thickness (r = −0.208, P = 0.004).

Conclusion

It is suggested that central fovea and outer retina thickness are respectively associated with WMH volume. OCT may be a biological marker for early detection and longitudinal monitoring of WMH.

Is ocular vascularity affected in young migraine patients? A pilot study

OBJECTIVE

This study aimed to evaluate ocular vascularity in young adult migraine patients with visual aura and without visual aura.

MATERIAL AND METHODS

The study included 30 patients with migraine with visual aura (MWVA), 30 patients with migraine without visual aura (MWOVA), and 30 healthy control subjects, all between ages ≥18 and <45. Migraine patients were applied Headache Impact Test (HIT) and Migraine Disability Assessment Scale (MIDAS). Retinal nerve fiber layer thickness and ocular vascularity of all participants were evaluated with optical coherence tomography (OCT) and OCT angiography (OCTA).

RESULTS

The MWVA group had significantly lower superficial and deep foveal vascular density values compared to the control group (p = 0.039, p = 0.028, respectively). The foveal avascular zone was significantly enlarged in the MWVA group compared to the control group (p = 0.033). MWVA patients had significantly lower whole optic disc, optic disc inside, peripapillary, superior hemisphere, inferior hemisphere, superior quadrant, and temporal quadrant vascular density values compared to the control group (p < 0.05 all), while there was no significant difference in the nasal quadrant (p = 0.083). Migraine attack frequency, MIDAS, and HIT were negatively correlated with ocular vascular density values.

CONCLUSION

The results of our study indicate that young adult patients with MWVA are at risk of decreased ocular vascularity and that this risk may increase with frequency and severity of migraine attacks.

Assessment of the outer retina and choroid in white matter lesions participants using swept-source optical coherence tomography

PURPOSE

To assess the three-dimensional outer retina thickness and choroid in eyes with white matter lesions (WMLs) using swept-source optical coherence tomography (SS-OCT).

METHODS

Participants without dementia and stroke with cerebral WMLs were enrolled in our study. Optical coherence tomography (OCT) and OCT angiography (OCTA) were used to image and evaluate the outer retinal layer, choroidal structure, and perfusion of the choriocapillaris, microvessels of the choroid, respectively. Measurement of the outer retinal thickness, choroidal thickness and perfusion of the choriocapillaris was done by the SS-OCT tool.

RESULTS

Thirty-one eyes from 16 WMLs and 40 eyes from 20 healthy controls were included in the data analyses. Outer retinal thickness was significantly reduced (P < .001) in WMLs participants when compared to healthy controls. Choroidal thickness was also significantly reduced (P < .001) in WMLs participants when compared to healthy controls. Choriocapillaris perfusion was significantly reduced (P = .002) in WMLs when compared to healthy controls. A significant correlation (Rho = .392, P = .032) was seen between the outer retinal thickness and choriocapillaris perfusion in WMLs participants.

CONCLUSIONS

Assessing retinal thickness and choroidal changes with the SS-OCTA as a proxy for WML could prove to be a potentially valuable tool for early detection of cognitive decline and other neurodegenerative diseases.

Retinal nerve fiber layer changes in migraine: a systematic review and meta-analysis

BACKGROUND

Migraine is one of the most common disabling diseases in the world. Its recurrent attacks may lead to abnormalities in the structure of the brain and retina. An increasing number of studies have investigated retinal nerve fiber layer (RNFL) thickness alterations in migraine by the optical coherence tomography (OCT); however, no consensus has yet reached.

METHOD

We searched Pubmed, Embase, and Web of Science databases to identify studies that investigated RNFL thickness in migraine by OCT measurement and performed a meta-analysis of eligible studies.

RESULTS

Twenty-six studies were included in the meta-analysis, comprising 1530 migraine patients and 1105 healthy controls. The mean RNFL thickness was thinner in the migraine group compared to the control group (SMD =- 0.53). In the subgroup analyses, RNFL thickness were decreased most significantly in the superior (SMD = - 0.71) and inferior (SMD = - 0.63) quadrants among all quadrants. Migraine with aura (SMD = - 0.91) showed a greater effect size of RNFL thickness reduction than migraine without aura (SMD =- 0.47). Spectral-domain OCT (SMD = - 0.55) seems more sensitive to detect RNFL thickness reduction than time-domain OCT (SMD = - 0.44). In addition, age, sex, disease duration, attack frequency, and intraocular pressure were not significantly associated with RNFL thickness.

CONCLUSIONS

The findings from our comprehensive meta-analysis with large datasets strengthen the clinical evidence of the RNFL thickness reduction in migraine. RNFL thickness via spectral-domain OCT measurement demonstrates the potential role in differentiating patients with migraine, especially migraine with aura, from healthy controls.