Self‐injurious behaviours in rhesus macaques: Potential glial mechanisms

Abstract

Background: Self-injurious behaviour (SIB) can be classified as intentional, direct injuring of body tissue usually without suicidal intent. In its non-suicidal form it is commonly seen as a clinical sign of borderline personality disorder, autism, PTSD, depression, and anxiety affecting a wide range of ages and conditions. In rhesus macaques SIB is most commonly manifested through hair plucking, self-biting, self-hitting, and head banging. SIB in the form of self-biting is observed in approximately 5–15% of individually housed monkeys. Recently, glial cells are becoming recognised as key players in regulating behaviors. Method: The goal of this study was to determine the role of glial activation, including astrocytes, in macaques that had displayed SIB. To this end, we performed immunohistochemistry and next generation sequence of brain tissues from rhesus macaques with self-injurious behaviours. Results: Our studies showed increased vimentin, but not nestin, expression on astrocytes of macaques displaying SIB. Initial RNA Seq analyses indicate activation of pathways involved in tissue remodeling, neuroinflammation and cAMP signaling. Conclusions: Glia are most probably activated in primates with self-injury, and are therefore potential novel targets for therapeutics.

Astrocytes in human central nervous system diseases: a frontier for new therapies

“…412 Likewise, astrocytes with small cell bodies and less complex processes were identified in Rhesus macaques with a self-injurious behaviour. 413 Partial ablation of astrocytes in the prefrontal cortex of healthy rats (by injection of gliotoxin L-α-aminoadipic acid) resulted in the development of depressive-like behaviours, whereas injection of neurotoxin ibotenate did not have such an effect. 404 Ablation of astrocytes also caused secondary damage to neurones translated into impaired working memory and learning.…”

Abnormality of anxious behaviors and functional connectivity between the amygdala and the frontal lobe in maternally deprived monkeys

“…Stereotyped behaviors are the mainfestation of anxious behaviors, typically characterized by repetitive, invariant patterns behavior that lack an obvious goal or function. Macaques can exhibit a wide range of stereotyped behaviors, including pacing, swing, bouncing, self‐biting, self‐grasping, and so on (Hwang et al., 2020 ; also see Bessa Ferreira et al., 2018 ; Ramsey et al., 2018 ). Pacing is a repetitive pattern of activity that follows an invariant path usually involving circling the cage.…”

Inflammation and emotional regulation: a narrative review of evidence and mechanisms in emotional dysregulation disorders

“…Preliminary evidence from animal models suggests that glial cells may be involved in regulating behaviours like self-injurious behaviours, which are a frequently seen clinical sign of BPD (385). In one study examining self-injurious macaques, results showed increased vimentin expression on astrocytes and activation of pathways involved in neuroinflammation, tissue remodelling, and cyclic adenosine monophosphate (cAMP) signalling, indicating that glial cells are potential therapeutic targets (386). This is significant, because findings have previously shown that the factor of ED is associated with a history of non-suicidal self-injury in BPD patients; however, this relationship is noted to be complex and precise mechanistical insight is still lacking (387).…”