Social Defeat Stress Model for Adolescent C57BL/6 Male and Female Mice.

Social adversity in adolescence is prevalent and can negatively impact mental health trajectories. Modeling social stress in adolescent male and female rodents is needed to understand its effects on ongoing brain development and behavioral outcomes. The chronic social defeat stress paradigm (CSDS) has been widely used to model social stress in adult C57BL/6 male mice by leveraging on the aggressive behavior displayed by an adult male rodent to an intruder invading its territory. An advantage of this paradigm is that it allows to categorize defeated mice into resilient and susceptible groups based on their individual differences in social behavior 24 h after the last defeat session. Implementing this model in adolescent C57BL/6 mice has been challenging because adult or adolescent mice do not typically attack early adolescent male or female mice and because adolescence is a short period of life, encompassing discreet temporal windows of vulnerability. This limitation was overcome by adapting an accelerated version of the CSDS to be used for adolescent male and female mice. This 4-day stress paradigm with 2 physical attack sessions per day uses a C57BL/6 male adult to prime the CD-1 mouse for aggressiveness such that it readily attacks the male or female adolescent mouse. This model was termed accelerated social defeat stress (AcSD) for adolescent mice. Adolescent exposure to AcSD induces social avoidance 24 h later in both males and females, but only in a subset of defeated mice. This vulnerability occurs despite the number of attacks being consistent across sessions between resilient and susceptible groups. The AcSD model is short enough to allow exposure during discrete periods within adolescence, allows the segregation of mice according to the presence or absence of social avoidance behavior, and is the first model available to study social defeat stress in adolescent C57BL/6 female mice.

Gains and Losses: Resilience to Social Defeat Stress in Adolescent Female Mice.

BACKGROUND: Adolescence is a unique period of psychosocial growth during which social adversity can negatively influence mental health trajectories. Understanding how adolescent social stress impacts males and females and why some individuals are particularly affected is becoming increasingly urgent. Social defeat stress models for adolescent male mice have been effective in reproducing some physical/psychological aspects of bullying. Designing a model suitable for females has proven challenging. METHODS: We report a version of the adolescent male accelerated social defeat stress (AcSD) paradigm adapted for females. Early adolescent C57BL/6J female mice (N = 107) were exposed to our modified AcSD procedure twice a day for 4 days and categorized as resilient or susceptible based on a social interaction test 24 hours later. Mice were then assessed for changes in Netrin-1/DCC guidance cue expression in dopamine systems, for inhibitory control in adulthood using the Go/No-Go task, or for alterations in dopamine connectivity organization in the matured prefrontal cortex. RESULTS: Most adolescent females showed protection against stress-induced social avoidance, but in adulthood, these resilient females developed inhibitory control deficits and showed diminution of prefrontal cortex presynaptic dopamine sites. Female mice classified as susceptible were protected against cognitive and dopaminergic alterations. AcSD did not alter Netrin-1/DCC in early adolescent females, contrary to previous findings with males. CONCLUSIONS: Preserving prosocial behavior in adolescent females may be important for survival advantage but seems to come at the price of developing persistent cognitive and dopamine deficiencies. The female AcSD paradigm produced findings comparable to those found in males, allowing mechanistic investigation in both sexes.

Amphetamine disrupts dopamine axon growth in adolescence by a sex-specific mechanism in mice.

Initiating drug use during adolescence increases the risk of developing addiction or other psychopathologies later in life, with long-term outcomes varying according to sex and exact timing of use. The cellular and molecular underpinnings explaining this differential sensitivity to detrimental drug effects remain unexplained. The Netrin-1/DCC guidance cue system segregates cortical and limbic dopamine pathways in adolescence. Here we show that amphetamine, by dysregulating Netrin-1/DCC signaling, triggers ectopic growth of mesolimbic dopamine axons to the prefrontal cortex, only in early-adolescent male mice, underlying a male-specific vulnerability to enduring cognitive deficits. In adolescent females, compensatory changes in Netrin-1 protect against the deleterious consequences of amphetamine on dopamine connectivity and cognitive outcomes. Netrin-1/DCC signaling functions as a molecular switch which can be differentially regulated by the same drug experience as function of an individual's sex and adolescent age, and lead to divergent long-term outcomes associated with vulnerable or resilient phenotypes.

Impact of school-supervised ultra-long-acting basal insulin injections on ketosis in youth with T1D and elevated haemoglobin A1c: A pilot study.

BACKGROUND: In youth with type 1 diabetes (T1D), high haemoglobin A1c (HbA1c) levels are associated with an increased risk for diabetic ketoacidosis (DKA). AIMS: This study examined whether daily school-supervised basal insulin injections were feasible and if they reduced the risk of morning ketosis in children and adolescents with high HbA1c levels. We hypothesized that supervised glargine and degludec would reduce the risk of ketosis and that the prolonged action of degludec would protect from ketosis after consecutive days of unsupervised injections. MATERIALS & METHODS: After a 2-4-week run-in, youth (10-18 years, HbA1c ≥ 8.5%) managing T1D with injections were randomized to school-supervised administration of degludec or glargine for 4 months. School nurses observed daily blood ß-hydroxybutyrate (BHB) and glucose checks. During COVID closures, the research team supervised procedures remotely. RESULTS: Data from 28 youth (age 14.3 ± 2.3 years, HbA1c 11.4 ± 1.9%, 64% F) were analysed. School-supervised injections of both basal insulins for 1-4 days progressively lowered the percent of participants with elevated BHB. The percent of participants with elevated BHB (≥0.6 mmol/L) after 2 days of unsupervised basal insulin doses at home was greater in the glargine than degludec group but had a high p-value (17.2% vs. 9.0%, p = 0.3). HbA1c was unchanged in both groups. DISCUSSION: In youth with T1D at high risk for DKA, daily supervised long-acting insulin administration decreased the probability of elevated ketone levels on subsequent school days, regardless of basal insulin type. A larger sample size may have demonstrated that the longer action profile of degludec would offer additional protection from ketosis during days of not attending school. CONCLUSION: Engaging school-based caregivers in management of youth with T1D on injected insulin may decrease clinically significant ketosis and minimize acute complications of diabetes.

Custom-Built Operant Conditioning Setup for Calcium Imaging and Cognitive Testing in Freely Moving Mice.

Operant chambers are widely used in animal research to study cognition, motivation, and learning processes. Paired with the rapidly developing technologies for brain imaging and manipulations of brain activity, operant conditioning chambers are a powerful tool for neuroscience research. The behavioral testing and imaging setups that are commercially available are often quite costly. Here, we present a custom-built operant chamber that can be constructed in a few days by an unexperienced user with relatively inexpensive, widely available materials. The advantages of our operant setup compared with other open-source and closed-source solutions are its relatively low cost, its support of complex behavioral tasks, its user-friendly setup, and its validated functionality with video imaging of behavior and calcium imaging using the UCLA Miniscope. Using this setup, we replicate our previously published findings showing that mice exposed to social defeat stress in adolescence have inhibitory control impairments in the Go/No-Go task when they reach adulthood. We also present calcium imaging data of medial prefrontal cortex (mPFC) neuronal activity acquired during Go/No-Go testing in freely moving mice and show that neuronal population activity increases from day 1 to day 14 of the task. We propose that our operant chamber is a cheaper alternative to its commercially available counterparts and offers a better balance between versatility and user-friendly setup than other open-source alternatives.

Unique effects of social defeat stress in adolescent male mice on the Netrin-1/DCC pathway, prefrontal cortex dopamine and cognition (Social stress in adolescent vs. adult male mice).

For some individuals, social stress is a risk factor for psychiatric disorders characterised by adolescent onset, prefrontal cortex (PFC) dysfunction and cognitive impairments. Social stress may be particularly harmful during adolescence when dopamine (DA) axons are still growing to the PFC, rendering them sensitive to environmental influences. The guidance cue Netrin-1 and its receptor, DCC, coordinate to control mesocorticolimbic DA axon targeting and growth during this age. Here we adapted the accelerated social defeat (AcSD) paradigm to expose male mice to social stress in either adolescence or adulthood and categorised them as "resilient" or "susceptible" based on social avoidance behaviour. We examined whether stress would alter the expression of DCC and Netrin-1 in mesolimbic dopamine regions and would have enduring consequences on PFC dopamine connectivity and cognition. While in adolescence the majority of mice are resilient but exhibit risk-taking behaviour, AcSD in adulthood leads to a majority of susceptible mice without altering anxiety-like traits. In adolescent, but not adult mice, AcSD dysregulates DCC and Netrin-1 expression in mesolimbic DA regions. These molecular changes in adolescent mice are accompanied by changes in PFC DA connectivity. Following AcSD in adulthood, cognitive function remains unaffected, but all mice exposed to AcSD in adolescence show deficits in inhibitory control when they reach adulthood. These findings indicate that exposure to AcSD in adolescence vs. adulthood has substantially different effects on brain and behaviour and that stress-induced social avoidance in adolescence does not predict vulnerability to deficits in cognitive performance.Significance statement During adolescence, dopamine circuitries undergo maturational changes which may render them particularly vulnerable to social stress. While social stress can be detrimental to adolescents and adults, it may engage different mechanisms and impact different domains, depending on age. The accelerated social defeat (AcSD) model implemented here allows exposing adolescent and adult male mice to comparable social stress levels. AcSD in adulthood leads to a majority of socially avoidant mice. However, the predominance of AcSD-exposed adolescent mice does not develop social avoidance, and these resilient mice show risk-taking behaviour. Nonetheless, in adolescence only, AcSD dysregulates Netrin-1/DCC expression in mesolimbic dopamine regions, possibly disrupting mesocortical dopamine and cognition. The unique adolescent responsiveness to stress may explain increased psychopathology risk at this age.

IgA-deficient humans exhibit gut microbiota dysbiosis despite secretion of compensatory IgM.

Immunoglobulin A is the dominant antibody isotype found in mucosal secretions and enforces host-microbiota symbiosis in mice, yet selective IgA-deficiency (sIgAd) in humans is often described as asymptomatic. Here, we determined the effects of IgA deficiency on human gut microbiota composition and evaluated the possibility that mucosal secretion of IgM can compensate for a lack of secretory IgA. We used 16S rRNA gene sequencing and bacterial cell sorting to evaluate gut microbiota composition and taxa-specific antibody coating of the gut microbiota in 15 sIgAd subjects and matched controls. Despite the secretion of compensatory IgM into the gut lumen, sIgAd subjects displayed an altered gut microbiota composition as compared to healthy controls. These alterations were characterized by a trend towards decreased overall microbial diversity as well as significant shifts in the relative abundances of specific microbial taxa. While secretory IgA in healthy controls targeted a defined subset of the microbiota via high-level coating, compensatory IgM in sIgAd subjects showed less specificity than IgA and bound a broader subset of the microbiota. We conclude that IgA plays a critical and non-redundant role in controlling gut microbiota composition in humans and that secretory IgA has evolved to maintain a diverse and stable gut microbial community.

Long-term application of glycine transporter inhibitors acts antineuropathic and modulates spinal N-methyl-D-aspartate receptor subunit NR-1 expression in rats.

BACKGROUND: Dysfunction of spinal glycinergic neurotransmission is a major pathogenetic factor in neuropathic pain. The synaptic glycine concentration is controlled by the two glycine transporters (GlyT) 1 and 2. GlyT inhibitors act antinociceptive in various animal pain models when applied as bolus. Yet, in some studies, severe neuromotor side effects were reported. The aim of the current study was to elucidate whether continuous inhibition of GlyT ameliorates neuropathic pain without side effects and whether protein expression of GlyT1, GlyT2, or N-methyl-D-aspartate receptor subunit NR-1 in the spinal cord is affected. METHODS: In the chronic constriction injury model of neuropathic pain, male Wistar rats received specific GlyT1 and GlyT2 inhibitors (ALX5407 and ALX1393; Sigma-Aldrich, St. Louis, MO) or vehicle for 14 days via subcutaneous osmotic infusion pumps (n = 6). Mechanical allodynia and thermal hyperalgesia were assessed before, after chronic constriction injury, and every 2 days during substance application. At the end of behavioral assessment, the expression of GlyT1, GlyT2, and NR-1 in the spinal cord was determined by Western blot analysis. RESULTS: Both ALX5407 and ALX1393 ameliorated thermal hyperalgesia and mechanical allodynia in a time- and dose-dependent manner. Respiratory or neuromotor side effects were not observed. NR-1 expression in the ipsilateral spinal cord was significantly reduced by ALX5407, but not by ALX1393. The expression of GlyT1 and GlyT2 remained unchanged. CONCLUSIONS: Continuous systemic inhibition of GlyT significantly ameliorates neuropathic pain in rats. Thus, GlyT represent promising targets in pain research. Modulation of N-methyl-D-aspartate receptor expression might represent a novel mechanism for the antinociceptive action of GyT1 inhibitors.

Effectiveness of a spanish language clinic for Hispanic youth with type 1 diabetes.

OBJECTIVE: A pilot study was undertaken to determine whether establishment of a Spanish Language Diabetes Clinic (SLDC) for Spanish-speaking families conducted by a team of Spanish-speaking, Hispanic and nonHispanic clinicians provides a means to improve control of type 1 diabetes (T1D). METHODS: The first 21 Hispanic pediatric patients with T1D who enrolled in the SLDC were matched to 21 Hispanic patients treated in the English Language Diabetes Clinic (ELDC) based on age and duration of diabetes. The two groups did not differ significantly with respect to gender, body mass index (BMI), or glycated hemoglobin (HbA1c). Patients in both groups were followed for 12 months. RESULTS: The mean (± standard deviation) baseline glycated hemoglobin (HbA1c) level in the SLDC group (8.4 ± 1.0%) was similar to that in the ELDC group (8.6 ± 1.4%, P = .83). HbA1c levels fell by 0.5 ± 1.0% (P = .01) during the year following enrollment in the SLDC but did not change significantly from baseline during the year of follow-up in the ELDC group (decrease of 0.2 ± 0.9%, P = .1). At the start of the study, only 5 patients (23%) in the SLDC group and 7 patients (33%) in the ELDC group met the ≤7.5% target HbA1c level. After 1 year, 10 of the SLDC patients (48%) and 4 of ELDC patients (19%) had HbA1c levels ≤7.5% (P = .01). CONCLUSIONS: Our preliminary findings support the hypothesis that overcoming language barriers by the establishment of a SLDC can be an effective means of improving metabolic control in youth with T1D in Hispanic families with limited English language skills.

A bridge to insulin pump therapy: twice-daily regimen with NPH and detemir insulins during initial treatment of youth with type 1 diabetes mellitus.

OBJECTIVE: To describe clinical outcomes in youth with new-onset type 1 diabetes mellitus (T1DM) treated with a modified, twice-daily regimen of a mixture of NPH insulin and rapid-acting insulin analogue at breakfast and separate injections of rapid-acting insulin analogue and insulin detemir at dinner. METHODS: Our clinic database was used to describe changes in insulin doses, hemoglobin A1c (A1C) levels, and frequency of severe hypoglycemia during the first year of therapy in young patients with T1DM diagnosed between September 2006 and April 2009. Data are presented as median values (25%, 75%). RESULTS: Overall, 108 patients (62 girls; mean age, 10.0 ± 0.4 years) were eligible for inclusion. Total daily insulin doses at 3, 6, and 12 months were 0.6 (0.4, 0.8), 0.7 (0.4, 0.9), and 0.8 (0.6, 0.9) U/kg, respectively. A1C levels were 9.8% (8.5%, 10.8%) at 2 weeks (baseline). Of the 108 patients, 19 had switched to insulin pump therapy by 3 months and 49 had switched by 12 months after initial diagnosis of T1DM. The 49 pump-treated patients had an A1C of 6.9% (6.6%, 7.3%), whereas the 59 injection-treated patients had an A1C of 7.2% (6.7%, 7.7%) by 12 months. There were only 6 severe hypoglycemic events in 5 patients; none occurred during the first 3 months, none occurred during the night, and all occurred in patients receiving insulin injection treatment. CONCLUSION: A twice-daily insulin regimen that uses insulin detemir for overnight basal replacement and morning NPH insulin to avoid lunch and afternoon snack doses is an effective initial treatment for young patients with new-onset T1DM that can provide a smooth transition to intensive basal/bolus insulin pump therapy.

Practical aspects of real-time continuous glucose monitors: the experience of the Yale Children's Diabetes Program.

Real-time continuous glucose monitoring (RT-CGM) provides new dimension to diabetes management. However, there are many challenges to using RT-CGM successfully. This article aims to present how RT-CGM is integrated into diabetes clinical practice at the Yale Children's Diabetes Program (YCDP). The authors provide factors to consider when choosing one of the commercially available RT-CGM systems and a discussion of key strategies for successful use of RT-CGM for families. Careful training and troubleshooting strategies will ensure the most positive experience possible for a family using RT-CGM.

Type 1 diabetes.

Type 1 diabetes is a tremendously challenging and complex disease for children and families to manage. Advances in research are constantly bringing about changes in therapies and treatments with the hope of improving the quality of life for youth with type 1 diabetes and their families. Accurate diagnosis, education, treatment, and referral to a certified diabetes educator, endocrinologist, dietitian, social worker, and psychologist are needed to provide the child with the skills necessary to manage diabetes over a lifetime. Nurses and nurse practitioners must be informed of the most current treatments and research available for their patients so that they can encourage their patients to live full and healthy lives.

Management of type 2 diabetes in youth (part 2).

Type 2 diabetes is increasing at an alarming rate in minority youth in the United States. Early diagnosis is important so that a treatment plan including diabetes self-management education, medical nutrition therapy, exercise, and behavioral modification can be developed to optimize blood glucose level. Prevention and treatment of hypertension and dyslipidemia may decrease cardiovascular disease later in life. Management of type 2 diabetes requires a team approach that is patient and family centered with the health care provider, a registered dietitian, an exercise physiologist, a social worker, and a psychologist available.

Understanding the development and prevention of type 2 diabetes in youth (part 1).

The prevalence of being at risk of overweight, overweight, pre-diabetes, and type 2 diabetes is increasing in the United States in youth. Primary care providers must understand how the emerging epidemic of type 2 diabetes developed during the past several decades to accurately diagnose it in young patients. Primary, secondary, and tertiary prevention interventions are needed to address the emerging epidemic of type 2 diabetes in youth. Primary prevention involves delaying the development of type 2 diabetes by reducing the prevalence of overweight. Secondary prevention is aimed at preventing those with pre-diabetes from developing diabetes, and tertiary prevention is aimed at preventing the complications of type 2 diabetes.

Quality of life in school-aged children with type 1 diabetes on intensive treatment and their parents.

PURPOSE: The purpose of this study was to examine the child, parent, and family factors associated with quality of life and metabolic control in school-aged children with type 1 diabetes on intensive treatment. METHODS: A cross-sectional analysis was performed of child, parent, and family psychosocial variables with child quality of life and metabolic control. RESULTS: Families of school-aged children were able to intensively manage type 1 diabetes, achieve good metabolic control (< 7.5%), experience good quality of life, and cope well with the demands of treatment. However, increased depressive symptoms were reported in children (8%) and a parent (29%). CONCLUSIONS: Most school-aged children and families in this sample coped well with the demands of intensive treatment. However, intensive psychosocial support may also be indicated because managing a complex chronic illness is stressful and potentially difficult for some families.