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The oxytocin system is regarded as being of relevance for social interaction. In spite of this, very few studies have investigated the relationship between oxytocin and personality traits in clinical psychiatric populations. We assessed the relationship between personality traits and plasma oxytocin levels in a population of 101 medication-free psychiatric outpatients (men = 37, women = 64). We used the Karolinska Scale of Personality (KSP) and diagnostic and symptomatic testing. Plasma oxytocin levels were analysed with a specific radioimmunoassay at inclusion and after one month for testing of stability. Plasma oxytocin levels were stable over time and did not differ between patients with or without personality disorders, nor were they related to severity of depressive or anxiety symptoms. The KSP factors Impulsiveness and Negative Emotionality were significant independent predictors of plasma oxytocin. A subscale analysis of these personality factors showed significant positive correlations between baseline plasma oxytocin and the KSP subscales monotony avoidance and psychic anxiety. The significant association between the KSP factor Impulsiveness and oxytocin levels observed at baseline was observed also one month later in men. These findings suggest that personality traits such as Impulsiveness and Negative emotionality which are linked to social functioning in several psychiatric disorders seem to be associated with endogenous plasma oxytocin levels. These variations in oxytocin levels might have an impact on social sensitivity or social motivation with possible gender differences.

Mental disorders and related behaviors such as suicidality and violence have been associated to dysregulation of e g carbohydrate metabolism. We hypothesized that patients after suicide attempt, compared to healthy controls, would have higher insulin and lower glucagon levels in plasma and cerebrospinal fluid and that these changes would be associated to violent behavior.

Twenty-eight medication-free patients (10 women, 18 men), hospitalized after suicide attempt, and 19 healthy controls (7 women, 12 men) were recruited with the aim to study risk factors for suicidal behavior. Psychological/psychiatric assessment was performed with SCID I and II or the SCID interview for healthy volunteers respectively, the Karolinska Interpersonal Violence Scale (KIVS) for assessment of lifetime violence expression behavior, the Montgomery-Åsberg-Depression-Scale (MADRS) and the Comprehensive Psychological Rating Scale (CPRS) for symptomatic assessment of depression and appetite. Fasting levels of insulin and glucagon were measured in plasma (P) and cerebrospinal fluid (CSF).

Suicide attempters had higher insulin- and lower glucagon-levels in plasma- and CSF compared to controls. Except for P-glucagon these associations remained significant after adjusting for age and/or BMI. Patients reported significantly more expressed interpersonal violence compared to healthy volunteers. Expressed violence was significantly positively correlated with P- and CSF-insulin and showed a significant negative correlation with P-glucagon in study participants. These findings confirm and extend prior reports that higher insulin and lower glucagon levels in plasma and cerebrospinal fluid are associated with suicidal behavior pointing towards a potential autonomic dysregulation in the control of insulin and glucagon secretion in suicidal patients.

Surgical intervention is the current gold standard treatment following peripheral nerve injury. However, this approach has limitations, and full recovery of both motor and sensory modalities often remains incomplete. The development of artificial nerve grafts that either complement or replace current surgical procedures is therefore of paramount importance. An essential component of artificial grafts is biodegradable conduits and transplanted cells that provide trophic support during the regenerative process. Neural crest cells are promising support cell candidates because they are the parent population to many peripheral nervous system lineages. In this study, neural crest cells were differentiated from human embryonic stem cells. The differentiated cells exhibited typical stellate morphology and protein expression signatures that were comparable with native neural crest. Conditioned media harvested from the differentiated cells contained a range of biologically active trophic factors and was able to stimulate in vitro neurite outgrowth. Differentiated neural crest cells were seeded into a biodegradable nerve conduit, and their regeneration potential was assessed in a rat sciatic nerve injury model. A robust regeneration front was observed across the entire width of the conduit seeded with the differentiated neural crest cells. Moreover, the up-regulation of several regeneration-related genes was observed within the dorsal root ganglion and spinal cord segments harvested from transplanted animals. Our results demonstrate that the differentiated neural crest cells are biologically active and provide trophic support to stimulate peripheral nerve regeneration. Differentiated neural crest cells are therefore promising supporting cell candidates to aid in peripheral nerve repair.