Researchers from the Department of Cell Biology, Genetics and Physiology at the University of Malaga have led an international scientific team that has studied how a traumatic brain injury caused by a severe blow to the head conditions the brain’s long-term response to subsequent stress situations.

Thus, in collaboration with the Wexner Medical Center of Ohio State University (Columbus, USA), this UMA team has demonstrated that the hypothalamus – a small region of the brain located at its base that connects the nervous system with the endocrine system and is activated in stressful situations, directing the body's response to such stressors – responds differently, in particular, triggering its inflammation, which is associated with avoidance-like and anxiety-like behavior.
The research, which so far has only been conducted in animal models, specifically analyzed the consequences of acute stress events in contexts of aggression and social defeat. The results of this study have been published in the scientific journal ‘Brain Behavior and Immunity’.

Changes at the cellular and molecular levels
“A previous traumatic brain injury can cause subtle, virtually undetectable changes at the cellular and molecular levels that persist over time and may, in the future, alter individuals’ behavior in response to subsequent stressful situations”, explains the scientist at the UMA María Dolores López, one of the authors of this study, which also involves researchers from IBIMA Plataforma BIONAND.

The expert also points out that microglia, which are largely responsible for trauma-associated neuroinflammation, play a very important role in the observed consequences of this injury. Thus, the research suggests that, after trauma, these cells acquire immune memory and become sensitized, resulting in increased activation to future stressors. “This is reflected in changes in cell morphology and an increased production of inflammatory mediators,” she says.

In addition, this study also revealed that these alterations in the brain do not translate into a greater increase in blood cortisol levels. In other words, the brain appears to respond differently to stress, although the systemic hormonal response is not amplified.

Significant role
This study was part of the thesis of the young researcher at the UMA Ana Léon, who, as part of her doctoral training, completed a research stay in the laboratory of Professor Jonathan P. Godbout at the Wexner Medical Center, a leading expert on the consequences of traumatic brain injuries and co-author of the study.

Their findings are consistent with clinical data indicating endocrine alterations in patients with traumatic injuries and shed light on the possible underlying mechanism, in which the hypothalamus and microglia may play a significant role.