Associations of the Fecal Microbial Proteome Composition and Proneness to Diet-induced Obesity.

Consumption of refined high-fat, low-fiber diets promotes development of obesity and its associated consequences. Although genetics play an important role in dictating susceptibility to such obesogenic diets, mice with nearly uniform genetics exhibit marked heterogeneity in their extent of obesity in response to such diets. This suggests non-genetic determinants play a role in diet-induced obesity. Hence, we sought to identify parameters that predict, and/or correlate with, development of obesity in response to an obesogenic diet. We assayed behavior, metabolic parameters, inflammatory markers/cytokines, microbiota composition, and the fecal metaproteome, in a cohort of mice (n = 50) prior to, and the 8 weeks following, administration of an obesogenic high-fat low-fiber diet. Neither behavioral testing nor quantitation of inflammatory markers broadly predicted severity of diet-induced obesity. Although, the small subset of mice that exhibited basal elevations in serum IL-6 (n = 5) were among the more obese mice in the cohort. While fecal microbiota composition changed markedly in response to the obesogenic diet, it lacked the ability to predict which mice were relative prone or resistant to obesity. In contrast, fecal metaproteome analysis revealed functional and taxonomic differences among the proteins associated with proneness to obesity. Targeted interrogation of microbiota composition data successfully validated the taxonomic differences seen in the metaproteome. Although future work will be needed to determine the breadth of applicability of these associations to other cohorts of animals and humans, this study nonetheless highlights the potential power of gut microbial proteins to predict and perhaps impact development of obesity.

Puberty and adolescence as a time of vulnerability to stressors that alter neurobehavioral processes.

Puberty and adolescence are major life transitions during which an individual's physiology and behavior changes from that of a juvenile to that of an adult. Here we review studies documenting the effects of stressors during pubertal and adolescent development on the adult brain and behavior. The experience of complex or compound stressors during puberty/adolescence generally increases stress reactivity, increases anxiety and depression, and decreases cognitive performance in adulthood. These behavioral changes correlate with decreased hippocampal volumes and alterations in neural plasticity. Moreover, stressful experiences during puberty disrupt behavioral responses to gonadal hormones both in sexual performance and on cognition and emotionality. These behavioral changes correlate with altered estrogen receptor densities in some estrogen-concentrating brain areas, suggesting a remodeling of the brain's response to hormones. A hypothesis is presented that activation of the immune system results in chronic neuroinflammation that may mediate the alterations of hormone-modulated behaviors in adulthood.

Methamphetamine-enhanced female sexual motivation is dependent on dopamine and progesterone signaling in the medial amygdala.

Methamphetamine (METH) is a psychomotor stimulant strongly associated with increases in sexual drive and impulsive sexual behaviors that often lead to unsafe sexual practices. In women METH users, such practices have been associated with increases in unplanned pregnancies and sexually transmitted diseases. Despite this significant heath concern, the neural mechanisms underlying this drug-sex association are not known. We previously established a rodent model of METH-facilitated female sexual behavior in which estradiol and progesterone interact with METH to increase motivational components of female behavior and neuronal activation in the posterodorsal medial amygdala (MePD) (Holder et al., 2010; Holder and Mong, 2010). The current study more directly examines the mechanisms underlying the drug-sex interaction. Here, we hypothesize that METH-induced increases in MePD dopamine signaling bridge the METH-hormone interaction. In support of this hypothesis, we found that excitotoxic lesions targeted to the MePD attenuated the METH-induced increases in proceptive behavior. Furthermore, infusion of a D1 agonist into the MePD increased proceptive behavior, while infusion of a D1 antagonist blocked the ability of METH to increase proceptive behaviors. Additionally, we found that METH-treatment increased progesterone receptor (PR) immunoreactivity in the MePD, suggesting an interaction between dopamine and progesterone signaling. Indeed, infusions of the PR antagonist, RU486, prevented METH-induced increases in sexual behavior. Thus, taken together, the current findings suggest that dopamine in the MePD modulates enhanced sexual motivation via an amplification of progesterone signaling and contributes to a better understanding of the neurobiology of drug-enhanced sexual behaviors.

Reduction of benztropine use duration in acute psychiatry: A quality improvement initiative.

DISCLAIMER: In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. PURPOSE: Secondary to the risk of antipsychotic-induced acute dystonia, prophylactic use of benztropine is occasionally warranted but is recommended for no longer than 7 days after initiating an antipsychotic, correlating to the period of highest dystonia risk. Despite the associated increased anticholinergic burden, many clinicians continue to order benztropine for periods exceeding the recommended prophylactic duration. We investigated the reduction of benztropine use duration subsequent to implementation of truncated electronic entry orders to improve benztropine prescribing within an acute psychiatric facility. METHODS: Data were collected for psychiatric inpatients admitted between January and June 2020 who were prescribed scheduled benztropine. In a quality improvement initiative implemented in April 2022, electronic orders for benztropine were modified from a 180-day to a 7-day duration, with subsequent postintervention data collection. The primary outcomes included a change in the duration of benztropine use for any indication in the hospital, and a change in the percentage of patients meeting predetermined "unnecessary use" criteria. Secondary analyses included the percentage of patients with discharge prescriptions for scheduled benztropine (either for prophylaxis or for other indications) in the pre- and postintervention periods. RESULTS: 73 pre- and 77 postintervention individual patients/encounters were included. Following the intervention, in-hospital duration of benztropine use for any indication decreased from a median of 14 days to a median of 7.5 days (P < 0.05), and appropriate use increased by 92.9%. The percentage of patients with prescriptions for scheduled benztropine decreased from 67.1% in the preintervention group to 29.9% in the postintervention group. CONCLUSION: Decreased benztropine use duration, by means of truncated order entry sentences, during inpatient psychiatric admissions, appears feasible regardless of dual antipsychotic or first-generation antipsychotic use, and may reduce the rates of benztropine prescriptions written for discharge.

Neuroendocrine effects of the duper mutation in Syrian hamsters: a role for Cryptochrome 1.

Molecular and physiological determinants of the timing of reproductive events, including the pre-ovulatory LH surge and seasonal fluctuations in fertility, are incompletely understood. We used the Cryptochrome 1-deficient duper mutant to examine the role of this core circadian clock gene in Syrian hamsters. We find that the phase of the LH surge and its stability upon shifts of the light: dark cycle are altered in duper mutants. The intensity of immunoreactive PER1 in GnRH cells of the preoptic area peaks earlier in the day in duper than wild type hamsters. We note that GnRH fibers coursing through the suprachiasmatic nucleus (SCN) contact vasopressin- and VIP-immunoreactive cells, suggesting a possible locus of circadian control of the LH surge. Unlike wild types, duper hamsters do not regress their gonads within 8 weeks of constant darkness, despite evidence of melatonin secretion during the subjective night. In light of the finding that the duper allele is a stop codon in Cryptochrome 1, our results suggest important neuroendocrine functions of this core circadian clock gene.

Safety and Efficacy of Early Vitamin D Supplementation in Critically Ill Extremely Preterm Infants: An Ancillary Study of a Randomized Trial.

BACKGROUND: Despite substantial evidence that vitamin D deficiency is highly prevalent among infants born extremely preterm (≤28 weeks' of gestation), several consensus statements do not recommend vitamin D doses >400 IU/day for these infants. Safety remains a concern. OBJECTIVE: The study aim was to determine safety and efficacy profiles of enteral vitamin D in Black and White infants randomized to three different vitamin D doses soon after birth. DESIGN: Ancillary study of a masked randomized clinical trial. PARTICIPANTS/SETTING: Seventy-three infants born extremely preterm between 2012 and 2015 at a southern US academic neonatal unit (33' latitude) who had >90% compliance with the assigned intervention were included. INTERVENTION: Infants were randomized to receive placebo (placebo group), 200 IU/day vitamin D (200 IU group), or 800 IU/day vitamin D (800 IU group) during the first 28 days after birth. MAIN OUTCOME MEASURES: Safety outcomes included serum 25-hydroxy vitamin D (25[OH]D) and calcium concentrations. Efficacy outcomes included the predictive risk of bronchopulmonary dysplasia. STATISTICAL ANALYSIS: Per-protocol analysis using unadjusted, repeated-measures mixed models. RESULTS: Mean birth weight was 815 ± 199 g. Half were male and 56% were Black. Of 58 infants with 25(OH)D measurements at birth, 40 (69%) had vitamin D deficiency (<20 ng/mL). The mean difference in 25(OH)D in nanograms per milliliter between Postnatal Day 28 and Postnatal Day 1 was +9 in the placebo group, +23 in the 200 IU group, and +62 in the 800 IU group (P < 0.0001). The increase observed in 25(OH)D was more significant among Black infants. The predictive risk of severe bronchopulmonary dysplasia in the 200 IU and 800 IU groups was lower, but this difference did not reach statistical significance. No vitamin D or calcium toxicity was observed. CONCLUSIONS: A vitamin D dose of 800 IU/day safely corrected vitamin D deficiency by Postnatal Day 14.

Methamphetamine enhances paced mating behaviors and neuroplasticity in the medial amygdala of female rats.

Methamphetamine (METH) is a psychomotor stimulant strongly associated with increases in sexual drive and behavior in women and men. Even though men and women are equally as likely to be addicted to or use METH, studies of sexual behavior often focus on male users. The paucity in studies examining the effect of METH in women is of great concern, when one considers the high correlation with sexually transmitted diseases such as HIV/AIDS and unplanned pregnancies. In fact, why METH so profoundly increases sexual drive is unknown. We have demonstrated that repeated exposure to METH enhances both receptivity and proceptivity in hormonally primed female rats. The current study examined whether a repeated exposure to METH enhanced female-initiated sexual behaviors in hormonally primed rats. In a paced mating paradigm, METH treatment significantly decreased the female's return latency following a mount (57%) and an ejaculation (44%), and the likelihood to leave the male following an intromission (37%) compared to controls. The METH-induced changes in paced mating behavior were accompanied by a 60% increase in spinophilin levels in the medial amygdala following hormonal priming and METH treatment. Taken together, these findings suggest that METH increases female sexual motivation and behavior in the rat potentially via changes in the neural substrate that require repeated exposure to the drug.

Estradiol Increases Microglial Response to Lipopolysaccharide in the Ventromedial Hypothalamus during the Peripubertal Sensitive Period in Female Mice.

Sensitive periods are times of development during which the effects of experience are unusually strong and long lasting. The peripubertal period has emerged as one such sensitive period, and a single administration of lipopolysaccharide (LPS) during this time reduces hormone-induced sexual behavior in adult female mice. During periods of high synaptic turnover, maturation, and elimination, as occurs during this sensitive period, microglia are particularly active. Estradiol also regulates microglial numbers, morphology, and activation. In addition, a good deal of evidence suggests that estradiol may confer this vulnerability to the effects of a stressor during the peripubertal period. Therefore, we investigated the effects of estradiol on microglial morphology, cytokine levels, and the sickness response to LPS. Estradiol levels were manipulated by implanting an estradiol-filled SILASTIC capsule (or oil-filled control) in ovariectomized mice or by administering the aromatase inhibitor, formestane (or oil control), to ovary-intact mice. We found that (1) estradiol elevates basal microglial Iba1 immunoreactivity in the ventromedial nucleus of the hypothalamus (VMH), (2) LPS induces higher levels of proinflammatory cytokines in the presence of estradiol, and (3) LPS causes hypothermia in the presence of estradiol. Taken together, these data suggest that estradiol enhances the effect of LPS during the pubertal sensitive period.

Sex, Drugs, and the Medial Amygdala: A Model of Enhanced Sexual Motivation in the Female Rat.

Methamphetamine (METH) is a psychomotor stimulant that is reported to enhance sexual desire and behavior in both men and women, leading to increases in unplanned pregnancies, sexually-transmitted infections, and even comorbid psychiatric conditions. Here, we discuss our rodent model of increased sexually-motivated behaviors in which the co-administration of METH and the ovarian hormones, estradiol and progesterone, intensify the incentive properties of a sexual stimulus and increases measures of sexually-motivated behavior in the presence of an androgen-specific cue. We then present the neurobiological mechanisms by which this heightened motivational salience is mediated by the actions of METH and ovarian hormones, particularly progestins, in the posterodorsal medial nucleus of the amygdala (MePD), a key integration site for sexually-relevant sensory information with generalized arousal. We finally demonstrate the cellular and molecular mechanisms underlying this facilitation of sexual motivation by METH, including the upregulation, increased phosphorylation, and activation of progestin receptors (PRs) in the MePD by METH in the presence of ovarian hormones. Taken together, this work extends our understanding of the neurobiology of female sexual motivation.

Dietary emulsifiers consumption alters anxiety-like and social-related behaviors in mice in a sex-dependent manner.

Dietary emulsifiers carboxylmethylcellulose (CMC) and polysorbate 80 (P80) alter the composition of the intestinal microbiota and induce chronic low-grade inflammation, ultimately leading to metabolic dysregulations in mice. As both gut microbiota and intestinal health can influence social and anxiety-like behaviors, we investigated whether emulsifier consumption would detrimentally influence behavior. We confirmed that emulsifier exposure induced chronic intestinal inflammation, increased adiposity, and altered gut microbiota composition in both male and female mice, although the specific microboal taxa altered following emulsifier consumption occurred in a sex-dependent manner. Importantly, emulsifier treatment altered anxiety-like behaviors in males and reduced social behavior in females. It also changed expression of neuropeptides implicated in the modulation of feeding as well as social and anxiety-related behaviors. Multivariate analyses revealed that CMC and P80 produced distinct clustering of physiological, neural, and behavioral effects in male and female mice, suggesting that emulsifier treatment leads to a syndrome of sex-dependent changes in microbiota, physiology, and behavior. This study reveals that these commonly used food additives may potentially negatively impact anxiety-related and social behaviors and may do so via different mechanisms in males and females.

Estradiol suppresses rapid eye movement sleep and activation of sleep-active neurons in the ventrolateral preoptic area.

Studies from multiple species, including humans, suggest that gonadal hormones, and ovarian hormones in particular, influence the physiology of sleep, but the mechanisms by which these hormones influence sleep behaviors are unknown. Previously, we demonstrated a 50% reduction in lipocalin-prostaglandin D synthase (L-PGDS) transcript levels, following estradiol treatment, at the level of the ventrolateral preoptic area (VLPO), a putative sleep-active nucleus. Catalytic activity of L-PGDS produces prostaglandin D(2) (PGD(2)), an endogenous somnogen. Based on our previous studies, we hypothesized that estradiol is acting via PGD(2) to suppress neuronal activity in the VLPO of females. To begin to test whether this is true, we quantified the number of Fos-immunopositive cells in hormonally manipulated male and female rats. We found that in females during the light phase, estradiol suppressed Fos expression in VLPO neurons. Interestingly, protein expression of L-PGDS followed the same pattern. Surprisingly, changes in the hormonal milieu of males had no effect. Using telemetry to record electroencephalograms from gonadally intact females, we found, in the light phase of proestrus when estradiol levels are high, a marked reduction in rapid eye movement (REM) sleep compared with the other days of the estrous cycle. However, during the dark phase of proestrus when estrogen and progesterone levels are elevated, significantly less time was spent in both non-REM and REM sleep. Thus, it seems that hormones in females play a major role in the regulation of sleep and arousal via activation of neurons in key sleep and arousal centers.

Impact of food additives on the gut-brain axis.

The mammalian intestinal tract is heavily colonized with a complex community of micro-organisms, present at a very high density, and containing an estimated amount of 1014 bacteria. The microbiota generally benefits the host, as it plays a central role in maturing the immune system, protecting against infection by entero-pathogens such as Clostridium difficile, and favoring nutrient digestion/energy extraction in our intestine. An altered microbiota, however, can become detrimental and lead to inflammation, metabolic disorders, and even altered behavior/neuroinflammation. While there are many factors involved in regulating the intestinal microbiota composition and the way it interacts with its host, this review will focus on the role played by food additives on host/microbiota relationship.

Developmental time course and effects of immunostressors that alter hormone-responsive behavior on microglia in the peripubertal and adult female mouse brain.

In female mice, the experience of being shipped from the breeder facility or a single injection of the bacterial endotoxin, lipopolysaccharide (LPS), during pubertal development alters the behavioral response to estradiol in adulthood as demonstrated by perturbations of estradiol's effects on sexual behavior, cognitive function, as well as its anxiolytic and anti-depressive properties. Microglia, the primary type of immunocompetent cell within the brain, contribute to brain development and respond to stressors with marked and long-lasting morphological and functional changes. Here, we describe the morphology of microglia and their response to shipping and LPS in peripubertal and adult female mice. Peripubertal mice have more microglia with long, thick processes in the hippocampus, amygdala and hypothalamus as compared with adult mice in the absence of an immune challenge. An immune challenge also increases immunoreactivity (IR) of ionized calcium binding adaptor molecule 1 (Iba1), which is constitutively expressed in microglia. In the hippocampus, the age of animal was without effect on the increase in Iba1- IR following shipping from the breeder facility or LPS exposure. In the amygdala, we observed more Iba1-IR following shipping or LPS treatment in peripubertal mice, compared to adult mice. In the hypothalamus, there was a disassociation of the effects of shipping and LPS treatment as LPS treatment, but not shipping, induced an increase in Iba1-IR. Taken together these data indicate that microglial morphologies differ between pubertal and adult mice; moreover, the microglial response to complex stressors is greater in pubertal mice as compared to adult mice.

The Role of Ovarian Hormones and the Medial Amygdala in Sexual Motivation.

PURPOSE: Although research into the neurobiology of sexual desire in women is active, relatively little is understood about the origins of sexual motivation in women. The purpose of our review is to discuss factors that influence a central sexual motivate state and generalized arousal as potential drivers of sexual motivation in women and female rats. RECENT FINDINGS: Sexual motivation is the product of interactions of the central motive state and salient sexually-relevant cues. Ovarian hormones and generalized arousal influence the central motive state, and endogenous levels of estradiol and progesterone correlate with sexual motivation and behavior in women. The amygdala is a key integratory site for generalized arousal and sexual sensory stimulation, which could then increase sexual motivation through its downstream projections. SUMMARY: Our model of enhanced female sexual motivation suggests that the combined effects of dopamine and progesterone receptor activation in the medial amygdala increases the incentive properties of a sexual stimulus. Further study into the interactions of ovarian hormones and mediators of generalized arousal on the processing of sexually-relevant cues informs our understanding of the neurobiology of female sexual motivation and could lead to the development of therapeutics to treat the dysfunctions of sexual desire in women.

Review: Puberty as a time of remodeling the adult response to ovarian hormones.

During pubertal development, an animal's response to stress changes and sexual differentiation of the brain and behavior continue. We discovered that particular stressors, such as shipping from suppliers or an immune challenge with lipopolysaccharide, during the prolonged pubertal period of female mice result in long-term changes in behavioral responsiveness of the brain to estradiol assessed in adulthood. All behaviors influenced by estradiol and/or progesterone that we have studied are compromised by a stressor during pubertal development. Depending on the behavior, immune challenge or shipping from suppliers during pubertal development decreases, eliminates, or even reverses the effects of estradiol. Shipping during this period causes changes in the number of estrogen receptor-immunoreactive cells in key brain areas suggesting one cellular mechanism for this remodeling of the brain's response to hormones. We suggest that particular adverse experiences in girls may cause long-term alterations in the brain's response to estradiol and/or progesterone via activation of the immune system. This in turn could lead to an alteration in any aspect of mental health that is influenced by estradiol.

Atypical Social Development in Vasopressin-Deficient Brattleboro Rats.

Over the past 3 decades, a large body of evidence has accumulated demonstrating that the neuropeptide arginine vasopressin (AVP) plays a critical role in regulating social behavior. The overwhelming majority of this evidence comes from adults, leaving a gap in our understanding of the role of AVP during development. Here, we investigated the effect of chronic AVP deficiency on a suite of juvenile social behaviors using Brattleboro rats, which lack AVP due to a mutation in the Avp gene. Social play behavior, huddling, social investigation & allogrooming, and ultrasonic vocalizations (USVs) of male and female rats homozygous for the Brattleboro mutation (Hom) were compared with their wild-type (WT) and heterozygous (Het) littermates during same-sex, same-genotype social interactions. Male and female Hom juveniles exhibited less social play than their Het and WT littermates throughout the rise, peak, and decline of the developmental profile of play. Hom juveniles also emitted fewer prosocial 50 kHz USVs, and spectrotemporal characteristics (call frequency and call duration) of individual call types differed from those of WT and Het juveniles. However, huddling behavior was increased in Hom juveniles, and social investigation and 22 kHz USVs did not differ across genotypes, demonstrating that not all social interactions were affected in the same manner. Collectively, these data suggest that the Avp gene plays a critical role in juvenile social development.

Differential responses of hippocampal neurons and astrocytes to nicotine and hypoxia in the fetal guinea pig.

In utero exposure to cigarette smoke has severe consequences for the developing fetus, including increased risk of birth complications and behavioral and learning disabilities later in life. Evidence from animal models suggests that the cognitive deficits may be a consequence of in utero nicotine exposure in the brain during critical developmental periods. However, maternal smoking exposes the fetus to not only nicotine but also a hypoxic intrauterine environment. Thus, both nicotine and hypoxia are capable of initiating cellular cascades, leading to long-term changes in synaptic patterning that have the potential to affect cognitive functions. This study investigates the combined effect of in utero exposure to nicotine and hypoxia on neuronal and glial elements in the hippocampal CA1 field. Fetal guinea pigs were exposed in utero to normoxic or hypoxic conditions in the presence or absence of nicotine. Hypoxia increased the protein levels of matrix metalloproteinase-9 (MMP-9) and synaptophysin and decreased the neural density as measured by NeuN immunoreactivity (ir). Nicotine exposure had no effect on these neuronal parameters but dramatically increased the density of astrocytes immunopositive for glial fibrillary acidic protein (GFAP). Further investigation into the effects of in utero nicotine exposure revealed that both GFAP-ir and NeuN-ir in the CA1 field were significantly reduced in adulthood. Taken together, our data suggest that prenatal exposure to nicotine and hypoxia not only alters synaptic patterning acutely during fetal development, but that nicotine also has long-term consequences that are observed well into adulthood. Moreover, these effects most likely take place through distinct mechanisms.

Methamphetamine facilitates female sexual behavior and enhances neuronal activation in the medial amygdala and ventromedial nucleus of the hypothalamus.

Methamphetamine (MA) abuse has reached epidemic proportions in the United States. Users of MA report dramatic increases in sexual drive that have been associated with increased engagement in risky sexual behavior leading to higher rates of sexually transmitted diseases and unplanned pregnancies. The ability of MA to enhance sexual drive in females is enigmatic since related psychostimulants like amphetamine and cocaine appear not to affect sexual drive in women, and in rodents models, amphetamine has been reported to be inhibitory to female sexual behavior. Examination of MA's effects on female sexual behavior in an animal model is lacking. Here, using a rodent model, we have demonstrated that MA enhanced female sexual behavior. MA (5mg/kg) or saline vehicle was administered once daily for 3 days to adult ovariectomized rats primed with ovarian steroids. MA treatment significantly increased the number of proceptive events and the lordosis response compared to hormonally primed, saline controls. The effect of MA on the neural circuitry underlying the motivation for sexual behavior was examined using Fos immunoreactivity. In the medial amygdala and the ventromedial nucleus of the hypothalamus, nuclei implicated in motivated behaviors, ovarian hormones and MA independently enhance the neuronal activation, but more striking was the significantly greater activation induced by their combined administration. Increases in dopamine neurotransmission may underlie the MA/hormone mediated increase in neuronal activation. In support of this possibility, ovarian hormones significantly increased tyrosine hydroxylase (the rate limiting enzyme in dopamine synthesis) immunoreactivity in the medial amygdala. Thus our present data suggest that the interactions of MA and ovarian hormones leads to changes in the neural substrate of key nuclei involved in mediating female sexual behaviors, and these changes may underlie MA's ability to enhance these behaviors.