Biomedical subjects

Erica R Glasper

Publications and source records attributed to Erica R Glasper.

9 recordsLinked to original sources

PubMed2006

Neonatal factors influence adult stroke outcome.

Neonatal environment can have important, life-long influences on stress-reactivity and hypothalamic-pituitary-adrenal (HPA) axis regulation. In rodents, brief mother-infant separations have been shown to improve efficiency of the HPA axis, decrease stress-reactivity, and decrease age-related declines in cognitive function. Here, we provide evidence that there are potential costs associated with improved HPA axis regulation, including increased sensitivity to cerebral inflammation and glucocorticoid-mediated neuronal death following stroke. Specifically, brief mother-infant separation decreases the initial corticosteroid response to experimental stroke in adult mice, but increases post-stroke pro-inflammatory cytokine expression, edema, and infarct volume compared to ischemic controls. Brief maternal separation also compromises functional recovery and long-term survival following stroke. In addition, adrenalectomy reverses the effects of brief maternal separation on stroke outcome when corticosterone is replaced at baseline, but not ischemic, concentrations; thus, neonatally separated mice are more sensitized as adults to the detrimental effects of elevated corticosterone during ischemia. Taken together, these data provide the first direct evidence that neonatal environment can substantially influence adult cerebrovascular health.

Adrenal Glands↗

PubMed2006

Prolonged separation delays wound healing in monogamous California mice, Peromyscus californicus, but not in polygynous white-footed mice, P. leucopus.

Social interactions are often stressful, but under certain circumstances, they may be beneficial for health and well-being. In a previous study, wound healing was slowed after mate separation (2 days) in monogamous California mice, Peromyscus californicus, but not polygynous white-footed mice, P. leucopus. Although these results indicate that positive social interaction is critical for immune activity in some species, the extent to which such social effects are enduring remains unspecified. The goal of the present experiments was to determine whether a period representing approximately 20% of expected adult lifespan of these species in the wild (8 weeks) would affect wound healing. Because our experimental design required that the same animals were wounded twice, we were also able to determine the extent to which wound healing is repeatable. Wound healing remained delayed after 8 weeks of separation in P. californicus, and healing scores were not correlated between first and second wounds within individuals. In P. leucopus however, housing conditions did not influence wound healing, but first and second wound healings were correlated indicating repeatability. In sum, our results suggest that positive social interactions may be important for promoting immune activity in some species.

Animals↗

PubMed2005

Social interaction improves experimental stroke outcome.

BACKGROUND AND PURPOSE: Social interaction can have a profound effect on health. The purpose of the present study was to determine whether affiliative social interactions before and after stroke improve ischemic outcomes as assessed through histological analysis and behavioral assays. METHODS: Male and female C57BL/6 mice were housed individually or with an ovariectomized female. Behavioral assessments were made 24 hours before 60 or 90 minutes of transient intraluminal middle cerebral artery occlusion (MCAO) or SHAM surgery and after 7 days of reperfusion. Two hours after behavioral testing on day 7, infarct size was determined by 2,3,5-triphenyltetrazolium histology, and blood samples were collected for assessment of corticosterone and C-reactive protein (CRP) concentrations. RESULTS: Pair housing significantly decreased infarct size and improved contralateral paw use in 60-minute MCAO males and 90-minute MCAO females compared with socially isolated cohorts. Housing condition had no significant effect on infarct size in females that underwent 60 minutes of MCAO, but pair housing was associated with improved contralateral paw use relative to socially isolated mice. In a separate cohort of males, intraischemic CRP concentration was significantly reduced in pair-housed males relative to isolated males. CONCLUSIONS: Affiliative interaction during the peri-ischemic period reduces intraischemic CRP concentration, decreases ischemic damage in male and female mice, and improves behavioral outcome.

Animals↗

PubMed2005

Social structure influences effects of pair-housing on wound healing.

Chronic stress or noxious stimuli delay wound healing in humans and rodents. The effects of stress on wound healing appear to be mediated by the hypothalamic-pituitary-adrenal (HPA) axis and, in particular, increases in corticosteroids. As previously shown, positive social interaction faciltiates wound healing through suppression of corticosteroids. In the present study, we investigated the effects of pair-housing on wound healing and corticosteroid concentrations in three mouse species, the monogamous Peromyscus californicus, the facultative-monogamous Peromyscus eremicus, and the polygynous Peromyscus leucopus. Pair-housed P. californicus and P. eremicus had significantly smaller wounds than socially isolated cohorts. However, wound healing in P. leucopus was not affected by housing condition. P. californicus and P. eremicus mice that were pair-housed for 2 weeks, then separated from their partners 48h prior to wounding also had wounds comparable to socially isolated mice. The benefits of social housing diminished when P. californicus and P. eremicus pairs were prevented from interacting physically via a double screen barrier. Two hours of daily restraint did not affect basal corticosterone concentrations or wound healing in either P. californicus or P. eremicus. In contrast, restraint facilitated wound healing in P. leucopus. Taken together, these data suggest that social contact facilitates wound healing in two monogamous, but not a polygynous, mouse species.

Analysis of Variance↗

PubMed2005

Maternal experience produces long-lasting behavioral modifications in the rat.

From 5 to 22 months of age, cognitive and emotional responses of nulliparous, primiparous, and multiparous rats were assessed using a dry land maze (DLM) and an elevated plus-maze (EPM) at 4-month intervals. Parous rats exhibited improved spatial memory in the probe and competitive versions of the DLM, and more exploration in the EPM and a novel stimulus test relative to nulliparous females. The nulliparous females, however, outperformed parous rats during the DLM visual cue test at 17 months of age. At 23 months, no differences in stressed corticosterone levels or Golgi-stained hippocampal neurons were observed. Thus, cognitive and emotional modifications were observed in parous rats; the neurobiological mechanisms for these enduring effects, however, remain to be identified.

Age Factors↗

PubMed2005

Cardiac arrest/cardiopulmonary resuscitation augments cell-mediated immune function and transiently suppresses humoral immune function.

Immune system activation has implications for cerebrovascular health, but little is known about the function of the immune system after a major cerebrovascular event, such as cardiac arrest and cardiopulmonary resuscitation (CA/CPR). Cardiac arrest and cardiopulmonary resuscitation damages the hippocampus, an important component of the hypothalamic-pituitary-adrenal (HPA) axis, and alterations in HPA axis activity can affect immune function. We tested the hypothesis that CA/CPR (approximately 8 mins) would cause HPA axis dysregulation and alter the delayed type hypersensitivity (DTH) response to antigenic challenge. We also assessed the primary and secondary antibody response of mice exposed to CA/CPR. Of the mice exposed to CA/CPR, half had brains protected by hypothermia to isolate the effects of the CA/CPR procedure from the effects of CA/CPR-induced neuronal damage. Cardiac arrest and cardiopulmonary resuscitation-induced neuronal damage resulted in a persistent elevation of blood corticosterone concentration and a concomitant augmentation of the DTH response to antigenic challenge. Furthermore, immune activation before CA/CPR decreased survival after global ischemia. These data highlight the potential impact of neuronal damage on cell-mediated immune function and the role of humoral immune activation in outcome after global ischemia.

Animals↗

PubMed2004

Social facilitation of wound healing.

It is well documented that psychological stress impairs wound healing in humans and rodents. However, most research effort into influences on wound healing has focused on factors that compromise, rather than promote, healing. In the present study, we determined if positive social interaction, which influences hypothalamic-pituitary-adrenal (HPA) axis activity in social rodents, promotes wound healing. Siberian hamsters received a cutaneous wound and then were exposed to immobilization stress. Stress increased cortisol concentrations and impaired wound healing in isolated, but not socially housed, hamsters. Removal of endogenous cortisol via adrenalectomy eliminated the effects of stress on wound healing in isolated hamsters. Treatment of isolated hamsters with oxytocin (OT), a hormone released during social contact and associated with social bonding, also blocked stress-induced increases in cortisol concentrations and facilitated wound healing. In contrast, treating socially housed hamsters with an OT antagonist delayed wound healing. Taken together, these data suggest that social interactions buffer against stress and promote wound healing through a mechanism that involves OT-induced suppression of the HPA axis. The data imply that social isolation impairs wound healing, whereas OT treatment may ameliorate some effects of social isolation on health.

Analysis of Variance↗

PubMed2004

Cardiac arrest with cardiopulmonary resuscitation reduces dendritic spine density in CA1 pyramidal cells and selectively alters acquisition of spatial memory.

The hippocampus is highly sensitive to ischemia and is one of the most extensively damaged regions of brain during cardiac arrest. Damage to hippocampus can subsequently lead to learning and memory deficits. The current study used the Morris water maze to characterize spatial learning and memory deficits elicited by 8 min of cardiac arrest with cardiopulmonary resuscitation (CA/CPR) in mice, which is associated with a 25-50% decrease in CA1 neurons. Mice were trained to navigate the water maze prior to CA/CPR or sham surgery (SHAM). They were retested in the water maze on days 7 and 8 postsurgery; both CA/CPR and SHAM groups were able to perform the task at presurgical levels. However, when the hidden platform was moved to a new location, the SHAM mice were able to adapt more quickly to the change and swam a shorter distance in search of the platform than did CA/CPR mice. Thus, CA/CPR did not affect the ability of mice to retain a previously learned platform location, but it did affect their ability to learn a new platform location. This behavioural impairment was correlated with dendritic spine density in the CA1 region of the hippocampus. Data presented here suggest that morphological changes, such as spine density, that occur in neurons that survive CA/CPR may be associated with cognitive impairments.

Animals↗

PubMed2003

Social modulation of stress responses.

Social interactions can profoundly affect the hypothalamic-pituitary-adrenal (HPA) axis. Although most research on social modulation of glucocorticoid concentrations has focused on the consequences of exposure to stressful social stimuli, there is a growing body of literature which suggests that social support in humans and affiliative behaviors in some animals can provide a buffer against stress and have a positive impact on measures of health and well-being. This review will compare HPA axis activity among individuals for whom social relationships are maintained through aggressive displays, such as dominance hierarchies, vs. individuals engaging in high levels of prosocial behavior. We also will examine oxytocin, a neuropeptide that is well known for promoting social behavior, as the physiological link between positive social interactions and suppression of the HPA axis. Despite many examples of social interaction modulating the HPA axis and improving health outcomes, there is relatively little known regarding the underlying mechanisms through which social behavior can provide a buffer against stress-related disease.

Adaptation, Physiological↗