Low levels of oxytocin – a naturally occurring hormone produced in the brain’s hypothalamus that also acts as a chemical messenger – have been found in cerebrospinal fluid (CSF) in Huntington’s disease A new study shows that patients with cognitive and social impairments.
The findings support oxytocin levels as a biomarker of poor social skills, as well as oxytocin administration as a potential treatment, according to the researchers.
Our findings on the relationship between low oxytocin levels in cerebrospinal fluid and decreased social cognition in HD. [Huntington’s disease] Opening possibilities for treatment trials to assess potential effects of oxytocin administration on social cognition,” the researchers wrote in their study, “Decreased oxytocin in cerebrospinal fluid is associated with measures of social cognitive impairment in patients with Huntington’s disease.which was published in Parkinson’s disease and related disorders.
Huntington’s disease is a genetic neurodegenerative disorder it causes by mutation in htt gene. This leads to excessive duplication of a segment of DNA, called CAG triplets, and longer production of the normal mutant huntingtin protein.
Mutant huntingtin (mHTT) accumulates to toxic levels within neurons in the brain, causing progressive neurodegeneration.
Common symptoms include depression, altered social cognition, metabolic changes, sleep disturbances, and altered functioning of the autonomic (autonomic) nervous system.
It is thought that Huntington’s psychiatric disorders may be related to changes in the hypothalamus, a brain region that controls sleep and growth, as well as hormone production.
Analysis of brain tissue from deceased Huntington’s patients showed changes in the hypothalamus, including a decrease in some hormone-producing neurons.
Exploring the oxytocin link between social cognition
In one study, A.J 45% decrease in neuronal production of oxytocin In the brain of people with Huntington’s disease, it has been reported compared to those without the disease. in Another studyThis decrease in oxytocin-expressing neurons was seen in the hypothalamus without changes in the striatum, a brain region involved in voluntary control of movement.
While best known for its role in breastfeeding and childbirth, oxytocin also helps regulate key aspects of human behaviors, including strengthening social interactions and interpreting emotional expressions.
In this study, a team led by researchers at the Danish Center for Dementia Research at Copenhagen University Hospital, Denmark hypothesized that low oxytocin levels could underlie, at least in part, early behavioral symptoms in Huntington’s patients.
Researchers measured levels of oxytocin in the blood and cerebrospinal fluid, which surrounds the brain and spinal cord, from 113 patients with Huntington’s disease positive for an enlarged CAG in the htt gene and 33 family relatives without gene expansion, who served as controls. Everyone underwent a psychological and cognitive assessment. Social cognition tests were also performed.
The results showed that oxytocin levels in the cerebrospinal fluid were significantly lower – an average decrease of 33.5% – in the Huntington’s group compared to the controls. No differences were observed in the blood samples from each group.
The researchers then divided the patients between those with obvious motor manifestations and those without motor manifestations, called Huntington’s Premanifest. Only subjects with Huntington’s motor disease retained a statistically significant difference relative to controls, an average decrease of 37.8% in oxytocin levels in the cerebrospinal fluid.
Although the Huntington’s patients also showed a lower level of oxytocin (mean decrease, 26.6%) than the control group, it was not statistically significant.
The team performed the same analysis but took disease progression into account, evaluating it using the Unified Huntington’s Disease Rating Scale (UHDRS) and a disease burden score, called the CAG age product (CAP), which takes into account the number of CAG repeats and age. However, no significant association was found between the two parameters and oxytocin levels.
These results indicate that the level of oxytocin in the cerebrospinal fluid “does not appear to be a surrogate marker of disease progression,” the researchers wrote.
Because their hypothesis centers on a possible link between oxytocin and non-motor symptoms, the researchers divided the Huntington’s disease group according to the presence of cognitive or psychological symptoms.
The results showed that oxytocin levels were significantly lower – by 30.3% – in those with cognitive impairment.
No differences were seen between patients without cognitive impairments and controls as well as patients with or without psychiatric symptoms.
Oxytocin as a biomarker of social cognition
A significant positive correlation—meaning one is greater, the higher the other—was found between the oxytocin level and patients’ scores on tests of social cognition, namely Reading the Mind in the Eyes (RME), the Affective Six Test (EHt), and the Social Inference Awareness Test (TASIT), which Assess social cognition using video clips of everyday conversations between two actors.
This means that patients who perform worse in social interactions have lower levels of oxytocin, supporting the use of oxytocin levels as a potential biomarker of social cognitive impairment.
The study showed that patients with Huntington’s disease “have a significantly lower level of oxytocin than controls and that the oxytocin level may represent an objective and comparable measure that can be used as a status biomarker of social cognitive impairment,” the researchers wrote.
The results also indicate that giving oxytocin may improve social cognition in these patients.
Our findings on the relationship between low oxytocin levels in cerebrospinal fluid and decreased social cognition in HD. [Huntington’s disease] Opening possibilities for treatment trials to assess the potential effects of oxytocin administration on social cognition in HD,” the researchers said.