Summary: An MRI study reveals neuroimaging can detect early signs of neurological damage in people with hypertension before symptoms of dementia occur.
Source: Oxford University Press.
A new study in Cardiovascular Research indicates that patients with high blood pressure are at a higher risk of developing dementia. This research also shows (for the first time) that an MRI can be used to detect very early signatures of neurological damage in people with high blood pressure, before any symptoms of dementia occur.
High blood pressure is a chronic condition that causes progressive organ damage. It is well known that the vast majority of cases of Alzheimer’s disease and related dementia are not due to genetic predisposition but rather to chronic exposure to vascular risk factors.
The clinical approach to treatment of dementia patients usually starts only after symptoms are clearly evident. However, it has becoming increasingly clear that when signs of brain damage are manifest, it may be too late to reverse the neurodegenerative process. Physicians still lack procedures for assessing progression markers that could reveal pre-symptomatic alterations and identify patients at risk of developing dementia.
Researchers screened subjects admitted at the Regional Excellence Hypertension Center of the Italian Society of Hypertension in the Department of Angiocardioneurology and Translational Medicine of the I.R.C.C.S, Neuromed, in Italy. Researchers recruited people aged 40 to 65, compliant to give written informed consent and with the possibility to perform a dedicated 3 Tesla MRI scan.
This work was conducted on patients with no sign of structural damage and no diagnosis of dementia. All patients underwent clinical examination to determine their hypertensive status and the related target organ damage. Additionally, patients were subjected to an MRI scan to identify microstructural damage.
To gain insights in the neurocognitive profile of patients a specific group of tests was administered. As primary outcome of the study the researchers aimed at finding any specific signature of brain changes in white matter microstructure of hypertensive patients, associated with an impairment of the related cognitive functions.
The result indicated that hypertensive patients showed significant alterations in three specific white matter fiber-tracts. Hypertensive patients also scored significantly worse in the cognitive domains ascribable to brain regions connected through those fiber-tracts, showing decreased performances in executive functions, processing speed, memory and related learning tasks.
Overall, white matter fiber-tracking on MRIs showed an early signature of damage in hypertensive patients when otherwise undetectable by conventional neuroimaging. As these changes can be detected before patients show symptoms, these patients could be targeted with medication earlier to prevent further deterioration in brain function. These findings are also widely applicable to other forms of neurovascular disease, where early intervention could be of marked therapeutic benefit.
“The problem is that neurological alterations related to hypertension are usually diagnosed only when the cognitive deficit becomes evident, or when traditional magnetic resonance shows clear signs of brain damage. In both cases, it is often too late to stop the pathological process” said Giuseppe Lembo, the coordinator of this study.
“We have been able to see that, in the hypertensive subjects, there was a deterioration of white matter fibers connecting brain areas typically involved in attention, emotions and memory, said Lorenzo Carnevale, IT engineer and first author of the study. “An important aspect to consider is that all the patients studied did not show clinical signs of dementia and, in conventional neuroimaging, they showed no signs of cerebral damage. Of course, further studies will be necessary, but we think that the use of tractography will lead to the early identification of people at risk of dementia, allowing timely therapeutic interventions.”
About this neuroscience research article
Funding: The study was supported by Italian Ministry of Health.
Source: Daniel Luzer – Oxford University Press Publisher: Organized by NeuroscienceNews.com. Image Source: NeuroscienceNews.com image is in the public domain. Original Research:Abstract for “Brain MRI fiber-tracking reveals white matter alterations in hypertensive patients without damage at conventional neuroimaging” by Lorenzo Carnevale, Valentina D’Angelosante, Alessandro Landolfi, Giovanni Grillea, Giulio Selvetella, Marianna Storto, Giuseppe Lembo, and Daniela Carnevale in Cardiovascular Research. Published June 12 2018 doi:10.1093/cvr/cvy104
[cbtabs][cbtab title=”MLA”]Oxford University Press “Hypertension May Cause Dementia.” NeuroscienceNews. NeuroscienceNews, 13 June 2018. <https://neurosciencenews.com/hypertension-dementia-9335/>.[/cbtab][cbtab title=”APA”]Oxford University Press (2018, June 13). Hypertension May Cause Dementia. NeuroscienceNews. Retrieved June 13, 2018 from https://neurosciencenews.com/hypertension-dementia-9335/[/cbtab][cbtab title=”Chicago”]Oxford University Press “Hypertension May Cause Dementia.” https://neurosciencenews.com/hypertension-dementia-9335/ (accessed June 13, 2018).[/cbtab][/cbtabs]
Brain MRI fiber-tracking reveals white matter alterations in hypertensive patients without damage at conventional neuroimaging
Aims Hypertension is one of the main risk factor for dementia. The subtle damage provoked by chronic high blood pressure in the brain is usually evidenced by conventional magnetic resonance imaging (MRI), in terms of white matter (WM) hyperintensities or cerebral atrophy. However, it is clear that by the time brain damage is visible, it may be too late hampering neurodegeneration. Aim of this study was to characterize a signature of early brain damage induced by hypertension, before the neurodegenerative injury manifests.
Methods and results This work was conducted on hypertensive and normotensive subjects with no sign of structural damage at conventional neuroimaging and no diagnosis of dementia revealed by neuropsychological assessment. All individuals underwent cardiological clinical examination in order to define the hypertensive status and the related target organ damage. Additionally, patients were subjected to DTI-MRI scan to identify microstructural damage of WM by probabilistic fiber-tracking. To gain insights in the neurocognitive profile of patients a specific battery of tests was administered. As primary outcome of the study we aimed at finding any specific signature of fiber-tracts alterations in hypertensive patients, associated with an impairment of the related cognitive functions. Hypertensive patients showed significant alterations in three specific WM fiber-tracts: the anterior thalamic radiation, the superior longitudinal fasciculus and the forceps minor. Hypertensive patients also scored significantly worse in the cognitive domains ascribable to brain regions connected through those WM fiber-tracts, showing decreased performances in executive functions, processing speed, memory, and paired associative learning tasks.
Conclusions Overall, WM fiber-tracking on MRI evidenced an early signature of damage in hypertensive patients when otherwise undetectable by conventional neuroimaging. In perspective, this approach could allow identifying those patients that are in initial stages of brain damage and could benefit of therapies aimed at limiting the transition to dementia and neurodegeneration.