Association of Cerebral Ischemia With Corneal Nerve Loss and Brain Atrophy in MCI and Dementia.

Georgios Ponirakis,Shafi Khan,Hamad Almuhannadi,Adnan Khan,Hanadi Al Hamad,Mani Chandran,Rayaz A Malik,Surjith Vattoth,Pravija Manikoth,Marwa Elorrabi,Ioannis N Petropoulos,Murtaza Qazi,Noushad Thodi,Ahmed Elsotouhy,Ahmed Own,Hoda Gad,Maryam Alobaidi,Rhia Tosino,Masharig Gadelseed,Salma Al-Mohannadi,Ashfaq Shuaib,Fatema Almarri,Marwan Ramadan,Ziyad Mahfoud ,Priya V Gawhale ,Yasmin H M Abdelrahim ,Fatima Al‐Khayat

doi:10.3389/fnins.2021.690896

Abstract

IntroductionThis study assessed the association of cerebral ischemia with neurodegeneration in mild cognitive impairment (MCI) and dementia.MethodsSubjects with MCI, dementia and controls underwent assessment of cognitive function, severity of brain ischemia, MRI brain volumetry and corneal confocal microscopy.ResultsOf 63 subjects with MCI (n = 44) and dementia (n = 19), 11 had no ischemia, 32 had subcortical ischemia and 20 had both subcortical and cortical ischemia. Brain volume and corneal nerve measures were comparable between subjects with subcortical ischemia and no ischemia. However, subjects with subcortical and cortical ischemia had a lower hippocampal volume (P < 0.01), corneal nerve fiber length (P < 0.05) and larger ventricular volume (P < 0.05) compared to those with subcortical ischemia and lower corneal nerve fiber density (P < 0.05) compared to those without ischemia.DiscussionCerebral ischemia was associated with cognitive impairment, brain atrophy and corneal nerve loss in MCI and dementia.

Highlights

This study assessed the association of cerebral ischemia with neurodegeneration in mild cognitive impairment (MCI) and dementia
Body weight and body mass index (BMI) were lower in subjects with both cortical and subcortical ischemia compared to subjects with subcortical ischemia (P < 0.05)
Cortical and subcortical ischemia was associated with neurodegeneration quantified by MRI brain volumetry and corneal confocal microscopy (CCM) in patients with MCI and dementia

Summary

Introduction

This study assessed the association of cerebral ischemia with neurodegeneration in mild cognitive impairment (MCI) and dementia. Cerebrovascular ischemic lesions are present in 11–94% of people aged ≥60 years (Debette and Markus, 2010) They increase the risk of cognitive impairment (Mungas et al, 2001) and dementia (Prins et al, 2004; Debette et al, 2010), depending on the person’s age, education and lifestyle, as well as the location and size of ischemic load (Roh and Lee, 2014). Corneal confocal microscopy (CCM) has shown significant corneal nerve loss in patients with TIA (Gad et al, 2019) and acute ischemic stroke (Khan et al, 2018) and has been associated with the presence of white matter hyperintensities after adjusting for age, diabetes, dyslipidemia and smoking (Kamran et al, 2020). We have previously reported that corneal nerve loss is associated with the severity of cognitive impairment and physical disability in patients with mild cognitive impairment (MCI) and dementia (Ponirakis et al, 2019a; Al-Janahi et al, 2020)

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