A recent study has identified a link between high levels of blood lipids and worsening of disease in multiple sclerosis (MS) patients who are overweight or obese. Following an extensive longitudinal investigation, conducted by the research team as part of this study, the researchers found that individuals who were overweight or obese had higher levels of blood lipids called ceramides, which placed markers on the DNA of monocytes, making them proliferate. Monocytes are blood cells that can travel to the brain and damage nerve fibres, and two years into their diagnosis, study participants with higher levels of ceramides and monocytes also had greater loss of motor skills and more brain injury.
"Our study identifies important correlations between ceramide levels, body mass index, and disease progression in MS patients," said Patrizia Casaccia, lead author of the study. As part of the study, researchers found that overweight and obese individuals with MS have higher ceramide levels than people with the disease who are not overweight and also those individuals who are overweight or obese but otherwise in healthy conditions.
According to them, these findings are important because "we and others had previously identified ceramides in the cerebrospinal fluid surrounding the brain of MS patients, and we attributed their increased abundance to the body's efforts to recycle the damaged myelin. In this study, however, we also detect higher ceramide levels in the blood of overweight and obese MS patients than we did in patients with normal body mass index, suggesting that overabundant lipids can be derived not only from damaged brain cells but also from excessive dietary intake of saturated fats," Casaccia asserted.
Researchers found that MS patients with high body mass indexes (BMIs) had higher ceramide levels and more circulating monocytes that were evident in healthy individuals with the same BMIs.
High-BMI MS patients showed worsening disability and more brain lesions at the MRI compared to their normal BMI counterparts. The researchers went on to find that ceramides can enter inside immune cells called monocytes and change the way these cells read the genetic information encoded in the DNA. These epigenetic changes were also found in monocytes circulating in the blood of MS patients with high BMI.
The detection of ceramides inside the nucleus of blood cells and the ability of these lipids to induce epigenetic changes suggests that saturated fatty acids may have long-lasting functional effects, which over time steer the MS disease course towards worsening disability. In short, bad dietary habits may have negative consequences in healthy subjects, but they have an even more pronounced deleterious effect on patients with MS because the degrading myelin can accumulate and further increase ceramide levels.
"This study gives us a much-needed view into the environmental influences that can affect and change the behaviour of cells in an individual's body. Our findings suggest that increased levels of saturated fat as a result of dietary habits are one likely cause of the epigenetic changes that advance MS, which gives us a starting point for potential intervention," explained Kamilah Castro, first author of the study published in the Journal of EBioMedicine.
The researchers' findings support the concept of nutri-epigenomics (the ability of food to modify the way genomic information is interpreted by each cell) and the idea that lifestyle factors such as diet and weight can function as disease modifiers. Additional studies on larger cohorts are needed to validate the current findings.
According to the researchers, further investigation is also needed to determine whether specific dietary interventions and weight management could be useful in helping MS patients manage and slow the progression of their disease and better respond to disease-modifying treatments.