The Function of Intestinal Afferent Neurons in Regulating Satiety During Health and Obesity

Background and aim: Within the gastrointestinal tract, vagal afferents regulate satiety and food intake via chemical and mechanical mechanisms. Cysteinyl Leukotrienes (CysLTs) are lipid mediators that are believed to regulate food intake and body weight. However, the involvement of vagal afferents in this effect remains to be established. Conversely, Glucagon like peptide-1 (GLP-1) is a satiety and incretin peptide hormone. The effect of obesity on GLP-1 mediated gut-brain signaling has yet to be investigated. Since intestinal vagal afferents’ activity is reduced during obesity, it is intriguing to investigate their responses to GLP-1 in such conditions. Methods: Extracellular recordings were performed on intestinal afferents from normal C57Bl6, low fat fed (LFF), and high fat fed (HFF) mice. To examine the effect on neuronal calcium signaling, calcium-imaging experiments were performed on isolated nodose ganglion neurons. Food intake experiments were conducted using LFF and HFF mice. Oral glucose tolerance tests (OGTT) were carried out. Whole cell patch clamp recordings were performed on nodose ganglion neurons from A) normal C57Bl mice to test the effect of CysLTs on membrane excitability, B) LFF and HFF mice to examine GLP-1 effect on membrane excitability during obesity. c-Fos immunohistochemical techniques were performed to measure the level of neuronal activation in the brainstem of both LFF and HFF mice in response to Ex-4. Results: CysLTs increased intestinal afferent firing rate and mechanosensitivity. In single nodose neuron experiments, CysLTs increased excitability. The GLP-1 agonist Ex-4 significantly decreased food intake in LFF but not HFF mice. However, Ex-4 markedly attenuated the rise in blood glucose in both LFF and HFF mice. The observed increase in nerve firing and mechanosensitivity following the application of GLP-1 and Ex-4 was abolished in HFF mice. Cell membrane excitability was significantly increased by Ex-4 in nodose from LFF but not HFF mice. Ex-4 significantly increased the number of activated neurons in the NTS area of LFF mice but not in their HFF counterparts. Conclusion: The previous observations indicate that the role CysLTs play in regulating satiety is likely to be vagally mediated. Also that satiety, but not incretin, effects of GLP-1 are impaired during obesity.

Maternal mental health and non-organic failure to thrive.

This study reports on the first phase of a large-scale, longitudinal, multidisciplinary community study examining the growth, learning and development of young children with a particular focus on failure to thrive without organic cause. However, the group identified in this study may be better described as weight faltering. This paper examines the psychological data collected using the Parenting Stress Index, Rosenberg Self-Esteem and the General Health Questionnaire in relation to child growth. There were no significant differences between the mothers of the weight faltering and control children in terms of parenting stress, maternal depression, maternal perceptions of their parenting competence or maternal self-esteem. Maternal sensitivity to comments about child size, regardless of direction, had a negative impact on mood.

The effects of maltreatment on children's health and well-being.

Although our society has put in place various forms of legislation to protect children's rights, many children are still subject to various forms of maltreatment such as sexual, physical or emotional abuse and/or physical or emotional neglect. All of these can have serious detrimental effects on the victims. Previous literature in this area has tended to focus on sexual abuse. In contrast, this paper provides an overview of all the different types of maltreatment in terms of characteristics of victims, the range of consequences, mediating factors and types of interventions that may be offered.

Oesophageal cancer: caregiver mental health and strain

Objective: To investigate strain and mental health among family caregivers of oesophageal cancer patients and possible factors associated with caregiver mental health and strain.

Methods: Patients with oesophageal adenocarcinoma in Ireland were recruited into the FINBAR study (the main aim of which was to investigate factors influencing the Barrett's adenocarcinoma relationship). Carers completed the 13-item Caregiver Strain Index and the General Health Questionnaire-30 (GHQ) in the context of a brief interview with trained research staff that was undertaken separately from the interview with each cancer patient.

Results: Two hundred and twenty-seven patients participated in the FINBAR study. A total of 39 patients did not have a family carer or the carer could not be identified. Fifty percent (94/188) of carers completed the questionnaires. Mean (SD) scores for strain (6.65, SD=3.63) and mental health status (10.21, SD=7.30) were high and 71% of carers scored >5 on the GHQ indicating psychological distress. There was a statistically significant positive relationship between level of strain experienced by caregivers and the severity of their mental health status and whether or not carers scored >5 on the GHQ. Relatives were 1.70 (95% CI 1.34-2.15) times more likely to be defined as high scorers with each unit increase in the CSI score.

Conclusions: A significant proportion of caregivers experienced high levels of strain and psychological distress. There is a need to provide appropriate support and services targeted specifically at reducing the considerable strain of caring for patients with oesophageal cancer, particularly for carers of patients from lower socioeconomic groups.