Nerve injury inhibits Oprd1 and Cnr1 transcription through REST in primary sensory neurons.

The transcription repressor REST in the dorsal root ganglion (DRG) is upregulated by peripheral nerve injury and promotes the development of chronic pain. However, the genes targeted by REST in neuropathic pain development remain unclear. The expression levels of 4 opioid receptor (Oprm1, Oprd1, Oprl1, Oprk1) and the cannabinoid CB1 receptor (Cnr1) genes in the DRG regulate nociception. In this study, we determined the role of REST in the control of their expression in the DRG induced by spared nerve injury (SNI) in both male and female mice. Transcriptomic analyses of male mouse DRGs followed by quantitative reverse transcription polymerase chain reaction analyses of both male and female mouse DRGs showed that SNI upregulated expression of Rest and downregulated mRNA levels of all 4 opioid receptor and Cnr1 genes, but Oprm1 was upregulated in female mice. Analysis of publicly available bioinformatic data suggested that REST binds to the promoter regions of Oprm1 and Cnr1. Chromatin immunoprecipitation analyses indicated differing levels of REST at these promoters in male and female mice. Full-length Rest conditional knockout in primary sensory neurons reduced SNI-induced pain hypersensitivity and rescued the SNI-induced reduction in the expression of Oprd1 and Cnr1 in the DRG in both male and female mice. Our results suggest that nerve injury represses the transcription of Oprd1 and Cnr1 via REST in primary sensory neurons and that REST is a potential therapeutic target for neuropathic pain.

Breastfeeding self-efficacy predicts breastmilk feeding in preterm infants at discharge from the neonatal intensive care unit.

AIM: To examine the association between breastfeeding self-efficacy (BSE) and breastmilk feeding at discharge from the neonatal intensive care unit among mothers of preterm infants. DESIGN: Secondary analysis of the Family Integrated Care (FICare) cluster randomized controlled trial. METHODS: Data from 221 mothers of preterm infants who participated in the standard care group of the trial were analysed. BSE at admission was assessed using the modified Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF). Breastmilk feeding was assessed using 24 hr maternal recall at discharge. RESULTS: Mothers who were exclusively breastmilk feeing their infants at discharge had statistically significantly higher mean BSES-SF scores at admission (68.4, SD = 13.7) than those providing a combination of breastmilk and formula or only formula (59.6, SD = 14.7; p < .001). Multivariable logistic regression showed that higher BSE at admission, maternal birth in Canada, and absence of diabetes were statistically significant predictors of exclusive breastmilk feeding at discharge.