Inflammation and dementia

Johns Hopkins University researchers working under the guidance of Professor Rebecca Gottesman have received additional evidence that progressive and chronic inflammation in middle and old age is associated with visible changes in the brain in people suffering from cognitive impairment and dementia.

Damage to the white matter of the brain in the image obtained by magnetic resonance imaging (from left to right – from light to heavy).

The data obtained by specialists have long indicated that chronic inflammation or the inflammatory status of the body, as well as associated biochemical compounds can damage brain tissue. For example, C-reactive protein, an inflammatory factor synthesized in the liver, is already being used as a biomarker of chemical damage to the heart and blood vessels preceding the development of myocardial infarction.

However, according to the authors, until now, when conducting such studies, scientists have not tracked the levels of such factors over a long period of time in the same population. As part of their work, they processed data collected during a study on the risk of atherosclerosis in different communities (atherosclerosis risk in communities, ARIC). During this study, 1,532 participants over the course of 21 years evaluated the parameters of the structure of the brain and its integrity, as well as markers of inflammation.

Each of the participants underwent 5 examinations, which were prescribed on average once every 3 years. During the last examination, participants who had reached an average age of 76 at that time underwent magnetic resonance imaging of the brain to identify and assess the severity of damage to the white matter - the region of the brain responsible for signal transmission. In the resulting image, the damaged areas have a bright white color, the intensity of which is estimated using an automated program.

During visits No. 2, 4 and 5, the researchers used a highly sensitive method to assess the content of C-reactive protein in the blood of participants, which is a universal marker of inflammation. The concentration of C-reactive protein below 3 mg per liter of blood serum was assessed as mild inflammation, whereas values exceeding 3 mg per liter corresponded to an increased level of inflammation.

Even after adjusting for demographic indicators, such as gender and level of education, as well as risk factors for cardiovascular diseases, the authors demonstrated that 90 participants whose C-reactive protein levels gradually increased from low to steadily increased from middle age had the most pronounced damage to the white matter of the brain.

Using a computer program that evaluates the structural integrity of tissue at the microscopic level, the authors found that according to this parameter, the brain of people with increasing levels of C-reactive protein in middle age is comparable to the brain of people 16 years older.

The relationship between chronic inflammation and white matter degeneration supports the existence of an association between progressive and chronic inflammation and the risk of dementia. However, the authors emphasize that they conducted an "observational study", the purpose of which was not to establish or prove a causal relationship. To do this, it is necessary to carry out further work on the identification of the exact mechanisms that trigger brain tissue damage.

The data obtained by the researchers are very important, since today neurodegenerative diseases do not have effective treatment methods, whereas inflammation can be a reversible factor, the elimination of which can delay the development of the disease or slow down its progression.

The most common causes of chronic inflammation include cardiovascular diseases, diabetes mellitus, high blood pressure and infectious diseases such as hepatitis C or HIV. It should also be remembered that inflammation is a normal byproduct of the aging process, but poor physical condition and damage to the body can aggravate the situation. The results of a number of studies indicate that reducing the severity of the inflammatory status can be achieved by treating and controlling the course of cardiovascular diseases, as well as maintaining a normal body weight.

Article by Keenan A.Walker et al. The association of mid-to late-life systemic inflammation with white matter structure in older adults: The Atherosclerosis Risk in Communities Study is published in the journal Neurobiology of Aging.

Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru Based on Johns Hopkins University: Mid- to Late-Life Increases in Marker of Chronic Inflammation Tied to Dementia.