Important new findings about how the “emotional brain” is affected early in HD

An article by by Prof Åsa Petersèn and Sanaz Gabery

This article is modified and translated from Lund University homepage, Agata Garpenlind.

Our results demonstrate that parts of the brain that manage emotions, the so-called limbic system, is affected early in HD mutation carriers.  These changes may contribute to the development of psychiatric and cognitive symptoms.  In many cases these are the most troublesome symptoms for both patients and their close family.

Our findings show that it’s not only the nerve cells that are affected in HD, but also other kinds of cells, like oligodendrocytes which play a major role in facilitating the communication between different parts in the brain, explains principal investigator Åsa Petersèn.  She is professor in neuroscience at Lund University (LU) and Senior Consultant  in psychiatry at the Huntington disease clinic in Lund, Sweden.

The study is another example of successful international collaborations in the HD field. In this case, between Petersén’s research group at LU and research teams headed by Associate Professor Mahmoud Pouladi (at the National University of Singapore and University of British Columbia, Vancouver, Canada), Professor Glenda Halliday (University of Sydney, Australia), Professor Nellie Georgiou-Karistianis (Monash University, Melbourne, Australia) as well as Professor Catriona McLean (Alfred Hospital, Melbourne, Australia).

Dr. Pouladi has recently published a number of research articles showing the effects of the disease causing protein mutant huntingtin in oligodendrocytes in experimental studies in HD. 

Image by Sanaz Gabery, postdoctoral fellow, Lund University (first author of the study)

The present study, published the 26th of August in the prestigious journal Acta Neuropathologica, demonstrates for the first time how the major white matter tract (fornix) in the emotional brain is affected in HD and that this may have relevance for the development of cognitive and psychiatric symptoms. 

The researchers demonstrate that fornix is smaller in HD brains and that this smaller size is connected to breakdown of a substance called myelin (important for fast communication between nerve cells)  and reduced functions of genes that influence the production of myelin as well as the identity of its producer, the oligodendrocytes.

This new research will further stimulate future studies on how and why oligodendrocytes and myelin are affected in HD. Understanding more about how the emotional brain is affected in HD will be important for patients and families as better treatments that are directed towards the troublesome cognitive and emotional symptoms are urgently needed. 

You can read the full article published in Acta Neuropathologica the 26th of August, 2021 here: “Early white matter pathology in the fornix of the limbic system in Huntington disease”