Early postnatal stress impairs insulin secretion in response to psychological stress in adult rats

Early adversity and the comorbidity between metabolic disease and psychopathology

Although the co-existence of metabolic and psychiatric disorders in the same individual (comorbidity) is very prevalent, the mechanisms by which these disorders co-occur are poorly understood, but a history of early-life adversity is a common developmental risk factor. Exposure to adverse environments during critical periods of development (e.g. fetal life and infancy) modifies the metabolism and the function of the brain persistently, influencing behaviours that contribute to both metabolic and mental health disarrangements over the life course. We will review molecular and clinical evidence supporting the notion that early adversity is an important risk factor for the comorbidity between metabolic and psychiatric conditions. We will also discuss the possible mechanisms involved: neurometabolic programming, epigenetic alterations and the cumulative effects of altered inflammatory and oxidative pathways linked to early adversity.

Lifestyle effects on aging and CVD: A spotlight on the nutrient-sensing network

Aging is widespread worldwide and a significant risk factor for cardiovascular disease (CVD). Mechanisms underlying aging have attracted considerable attention in recent years. Remarkably, aging and CVD overlap in numerous ways, with deregulated nutrient sensing as a common mechanism and lifestyle as a communal modifier. Interestingly, lifestyle triggers or suppresses multiple nutrient-related signaling pathways. In this review, we first present the composition of the nutrient-sensing network (NSN) and its metabolic impact on aging and CVD. Secondly, we review how risk factors closely associated with CVD, including adverse life states such as sedentary behavior, sleep disorders, high-fat diet, and psychosocial stress, contribute to aging and CVD, with a focus on the bridging role of the NSN. Finally, we focus on the positive effects of beneficial dietary interventions, specifically dietary restriction and the Mediterranean diet, on the regulation of nutrient metabolism and the delayed effects of aging and CVD that depend on the balance of the NSN. In summary, we expound on the interaction between lifestyle, NSN, aging, and CVD.

Early life adversity as a risk factor for cognitive impairment and Alzheimer's disease

Neurological conditions, including cognitive impairment and Alzheimer's disease (AD), impose a huge burden on society, affecting millions of people globally. In addition to genetic factors, recent studies indicate that environmental and experiential factors may contribute to the pathogenesis of these diseases. Early life adversity (ELA) has a profound impact on brain function and health later in life. In rodent models, exposure to ELA results in specific cognitive deficits and aggravated AD pathology. Extensive concerns have been raised regarding the higher risk of developing cognitive impairments in people with a history of ELA. In this review, we scrutinize findings from human and animal studies focusing on the connection of ELA with cognitive impairment and AD. These discoveries suggest that ELA, especially at early postnatal stages, increases susceptibility to cognitive impairment and AD later in life. In terms of mechanisms, ELA could lead to dysregulation of the hypothalamus-pituitary-adrenal axis, altered gut microbiome, persistent inflammation, oligodendrocyte dysfunction, hypomyelination, and aberrant adult hippocampal neurogenesis. Crosstalks among these events may synergistically contribute to cognitive impairment later in life. Additionally, we discuss several interventions that may alleviate adverse consequences of ELA. Further investigation into this crucial area will help improve ELA management and reduce the burden of related neurological conditions.

Early Chronic Stress Induced Changes within the Locus Coeruleus in Sporadic Alzheimer's Disease

Chronic exposure to stress throughout the lifespan has been the focus of many studies on Alzheimer's disease (AD) because of the similarities between the biological mechanisms involved in chronic stress and the pathophysiology of AD. In fact, the earliest abnormality associated with the disease is the presence of phosphorylated tau protein in locus coeruleus neurons, a brain structure highly responsive to stress and perceived threat. Here, we introduce allostatic load as a useful concept for understanding many of the complex, interacting neuropathological changes involved in the AD degenerative process. In response to chronic stress, aberrant tau proteins that begin to accumulate within the locus coeruleus decades prior to symptom onset appear to represent a primary pathological event in the AD cascade, triggering a wide range of interacting brain changes involving neuronal excitotoxicity, endocrine alterations, inflammation, oxidative stress, and amyloid plaque exacerbation. While it is acknowledged that stress will not necessarily be the major precipitating factor in all cases, early tau-induced changes within the locus coeruleus-norepinephrine pathway suggests that a therapeutic window might exist for preventative measures aimed at managing stress and restoring balance within the HPA axis.

Cortisol, Maternal Stress, and Breastfeeding Rate at Hospital Discharge: A Systematic Review

Introduction: Breastfeeding is considered the best way to provide essential and necessary nutrients to the newborn, intervening in its growth and development. However, early abandonment of this method is quite common, due to various factors such as stress. Objectives: To determine whether the level of postpartum cortisol can serve as an indicator of maternal stress and whether there is a relationship between the level of cortisol and the rate of exclusive breastfeeding (EBF) at hospital discharge. Methodology: Systematic review of the literature under the PRISMA guidelines. PubMed, Web of Science, CINAHL, and Scopus databases were used. Original articles published from 2017 to 2022 in English, French, Portuguese, and Spanish were included. All study designs were eligible. Of the 3,712 records initially identified, 15 studies were included in this review. Results: Elevated cortisol levels, due to immediate postpartum stressors, have direct effects on the performance of the essential hormones in breast milk production. The EBF rates are negatively influenced by perceived maternal stress. Conclusion: Cortisol levels may be a good indicator of the level of stress to which the mother is subjected during the immediate postpartum period.

Maternal Psychological Distress and Lactation and Breastfeeding Outcomes: a Narrative Review

PURPOSE

Despite recommendations from the World Health Organization and the American Academy of Pediatrics to exclusively breastfeed infants for their first 6 months of life, 75% of women do not meet exclusive breastfeeding guidelines, and 60% do not meet their own breastfeeding goals. Numerous observational studies have linked maternal psychological distress (eg, perceived stress, anxiety, and depression) with nonoptimal breastfeeding outcomes, such as decreased proportion and duration of exclusive breastfeeding. The physiological mechanisms underlying these associations, however, remain unclear.

METHODS

For this narrative review, we evaluated the evidence of relationships between maternal psychological distress and lactation and breastfeeding outcomes in pregnancy and post partum and the possible physiological mechanisms that facilitate these relationships. We searched PubMed using the following terms: stress, anxiety, depression, breastfeeding, and lactation. Additional search by hand was conducted to ensure a thorough review of the literature.

FINDINGS

Among the studies examined, methods used to assess maternal psychological distress were not uniform, with some studies examining perceived distress via a variety of validated tools and others measuring biological measures of distress, such as cortisol. Evidence supports a role for psychological distress in multiple breastfeeding outcomes, including delayed secretory activation and decreased duration of exclusive breastfeeding. One physiological mechanism proposed to explain these relationships is that psychological distress may impair the release of oxytocin, a hormone that plays a critical role in milk ejection during lactation. Continued impairment of milk ejection may lead to decreased milk production because of incomplete emptying of the breast during each feed. Maternal distress may also yield elevated levels of serum cortisol and decreased insulin sensitivity, which are associated with decreased milk production. The relationship between psychological distress and breastfeeding is likely to be bidirectional, however, in that breastfeeding appears to reduce maternal distress, again possibly via effects on the pleasure or reward pathway and calming effects of oxytocin on the mother. This finding suggests that interventions to support lactation and breastfeeding goals in women who score high on measures of psychological distress would be beneficial for both maternal and infant well-being.

IMPLICATIONS

Evidence to date suggests that maternal psychological distress may impair lactation and breastfeeding outcomes, but stronger study designs and rigorous assessment methods are needed. A better understanding of the physiological mechanisms leading to impaired lactation may assist in the development of early interventions for mothers experiencing distress. In addition, stress-reducing programs and policies should be investigated for their potential to improve breastfeeding outcomes.