Afternoon distraction: a high-saturated-fat meal and endotoxemia impact postmeal attention in a randomized crossover trial

Couples in breast cancer survivorship: Daily associations in relationship satisfaction, stress, and health

Romantic relationships are a key health determinant underlying both morbidity and mortality. Dr. Janice Kiecolt-Glaser's prolific research revealed cardiovascular, metabolic, endocrine, and immune pathways connecting marriage to health and longevity. In addition to her empirical work, she developed conceptual models on marriage, the gut microbiome, stress reactivity, and spousal health concordance; these models guide and inspire mechanistic research, serve as essential readings for graduate students and mentees, and provide inspiration for researchers across career stages. This paper highlights Dr. Kiecolt-Glaser's influential work, includes personal reflections and professional growth as past mentees, and provides Dr. Kiecolt-Glaser-inspired evidence linking relationships to health among couples in breast cancer survivorship. Using baseline questionnaires and daily dairies, breast cancer survivors (stage I-IIIB) and their cohabiting partners (60 individuals, 30 couples) rated their relationship satisfaction, stress, and physical health symptoms every day for 7 days. Results suggest that breast cancer survivors and their partners who felt more satisfied with their relationships also felt less stressed, both typically and on a daily basis. Survivors' and partners' lower stress was also associated with fewer physical health problems on average and in daily life. These findings demonstrate the daily stress and health advantages of satisfying relationships for both breast cancer survivors and their partners. We discuss the study's implications and several avenues for Dr. Kiecolt-Glaser-inspired research addressing a relationship's long-term health impact among couples in survivorship.

Psychoneuroimmunology and the research of Janice Kiecolt-Glaser: It informs self-care and the practice of medicine

Dr. Janice Kiecolt-Glaser as an undergraduate obtained a major in psychology and a minor in biological sciences which was an early indication of her budding interest in how the brain talks to a variety of physiologic systems. Early in her research career Jan began to build a research team that eventually consisted of scientists with expertise in a variety of disciplines including virology, immunology, endocrinology, nutrition science, biostatistics, genetics, and the microbiome. Additionally, Jan enlisted the aid of a group of bright energetic pre- and post-doctoral graduate students, obtained numerous NIH grants, and utilized an excellent Clinical Research Center. Over many years Jan directed these teams to help with understanding some of the biologic consequences of common life stressors such as loneliness, academic examinations, marital discord, breast cancer survivorship, and dementia caregiving. In this survey of her accomplishments, I will present some of the highlights of her prolific contributions which have encouraged many to enter the field of psychoneuroimmunology.

A social science: Using psychoneuroimmunology principles to promote career longevity, productivity, and meaning

Over the past several decades, psychoneuroimmunologists have uncovered key principles (e.g., social support and stress management) that can inform future research content and conduct. That is, psychoneuroimmunology (PNI) can inform how scientists from all disciplines engage in the scientific method in a more sustainable manner. Dr. Janice Kiecolt-Glaser, a PNI pioneer, recently ended her long and celebrated career. Her unique engagement in the scientific method, including her mentorship style, is worthy of closer examination. As her final graduate student, I observed Dr. Kiecolt-Glaser's science and mentorship style at their full maturity. Her scientific content, remarkable in its own right, is the subject of commentaries and accolades; yet, her scientific conduct - the foundation of her success and innovation - deserves further consideration. This article outlines ten research conduct principles that Dr. Kiecolt-Glaser explicitly and implicitly taught: (1) applying the literature to one's own health behaviors; (2) knowing and remembering "the why" behind the science; (3) developing and adhering to a vision; (4) creating a streamlined workflow; (5) embracing team science; (6) pursuing depth and breadth; (7) communicating ideas clearly; (8) engaging in a daily rhythm of science; (9) treating trainees like future primary investigators; and (10) working toward clinical meaningfulness. These principles correspond to PNI findings and account for her health and longevity as a scientist.

Plant foods, healthy plant-based diets, and type 2 diabetes: a review of the evidence

Type 2 diabetes (T2D) is a metabolic chronic disease in which insulin resistance and insufficient insulin production lead to elevated blood glucose levels. The prevalence of T2D is growing worldwide, mainly due to obesity and the adoption of Western diets. Replacing animal foods with healthy plant foods is associated with a lower risk of T2D in prospective studies. In randomized controlled trials, the consumption of healthy plant foods in place of animal foods led to cardiometabolic improvements in patients with T2D or who were at high risk of the disease. Dietary patterns that limit or exclude animal foods and focus on healthy plant foods (eg, fruits, vegetables, whole grains, nuts, legumes), known as healthy, plant-based diets, are consistently associated with a lower risk of T2D in cohort studies. The aim of this review is to examine the differential effects of plant foods and animal foods on T2D risk and to describe the existing literature about the role of healthy, plant-based diets, particularly healthy vegan diets, in T2D prevention and management. The evidence from cohort studies and randomized controlled trials will be reported, in addition to the potential biological mechanisms that seem to be involved.

Dietary fat, telomere length and cognitive function: unravelling the complex relations

PURPOSE OF REVIEW

The review aims to explore the recent evidence on the associations between different dietary fat intake and cognitive function, and to understand the role of telomere length in this relationship.

RECENT FINDINGS

Clinical and preclinical studies included in this review suggest that dietary fat intake is associated with cognitive function and telomere length. High intake of saturated fats and trans fats, commonly found in ultra-processed foods, appears to have negative effects on cognitive function and telomere length, while other dietary fats, such as omega-3 polyunsaturated fatty acids and monounsaturated fatty acids are associated with improved cognitive performance and reduced telomere attrition. Controversial results related to omega-6 polyunsaturated fatty acids intake and its impact on cognitive function were found. Dietary fats may affect telomere length and cognition through oxidative stress, inflammation, and insulin resistance.

SUMMARY

The current review illustrated the relationship between dietary fat and cognitive function by focusing on the role of telomere length as a potential intermediator. More future studies are required, however, in order to develop targeted interventions aimed at preserving cognitive well-being throughout life.

Minding the gut: extending embodied cognition and perception to the gut complex

Scientific and philosophical accounts of cognition and perception have traditionally focused on the brain and external sense organs. The extended view of embodied cognition suggests including other parts of the body in these processes. However, one organ has often been overlooked: the gut. Frequently conceptualized as merely a tube for digesting food, there is much more to the gut than meets the eye. Having its own enteric nervous system, sometimes referred to as the "second brain," the gut is also an immune organ and has a large surface area interacting with gut microbiota. The gut has been shown to play an important role in many physiological processes, and may arguably do so as well in perception and cognition. We argue that proposals of embodied perception and cognition should take into account the role of the "gut complex," which considers the enteric nervous, endocrine, immune, and microbiota systems as well as gut tissue and mucosal structures. The gut complex is an interface between bodily tissues and the "internalized external environment" of the gut lumen, involved in many aspects of organismic activity beyond food intake. We thus extend current embodiment theories and suggest a more inclusive account of how to "mind the gut" in studying cognitive processes.

Depression, Inflammation, and Intestinal Permeability: Associations with Subjective and Objective Cognitive Functioning throughout Breast Cancer Survivorship

About one-in-three breast cancer survivors have lingering cognitive complaints and objective cognitive impairment. Chronic inflammation and intestinal permeability (i.e., leaky gut), two risk factors for cognitive decline, can also fuel depression-another vulnerability for cognitive decline. The current study tested whether depression accompanied by high levels of inflammation or intestinal permeability predicted lower subjective and objective cognitive function in breast cancer survivors. We combined data from four breast cancer survivor studies (n = 613); some had repeated measurements for a total of 1015 study visits. All participants had a blood draw to obtain baseline measures of lipopolysaccharide binding protein-a measure of intestinal permeability, as well as three inflammatory markers that were incorporated into an inflammatory index: C-reactive protein, interleukin-6, and tumor necrosis factor-α. They reported depressive symptoms on the Center for Epidemiological Studies depression scale (CES-D), and a binary variable indicated clinically significant depressive symptoms (CES-D ≥ 16). The Kohli (749 observations) and the Breast Cancer Prevention Trial (591 observations) scales assessed subjective cognitive function. Objective cognitive function tests included the trail-making test, Hopkins verbal learning test, Conners continuous performance test, n-back test, FAS test, and animal-naming test (239-246 observations). Adjusting for education, age, BMI, cancer treatment type, time since treatment, study visit, and fatigue, women who had clinically elevated depressive symptoms accompanied by heightened inflammation or intestinal permeability reported poorer focus and marginally poorer memory. However, poorer performance across objective cognitive measures was not specific to inflammation-associated depression. Rather, there was some evidence of lower verbal fluency; poorer attention, verbal learning and memory, and working memory; and difficulties with visuospatial search among depressed survivors, regardless of inflammation. By themselves, inflammation and intestinal permeability less consistently predicted subjective or objective cognitive function. Breast cancer survivors with clinically significant depressive symptoms accompanied by either elevated inflammation or intestinal permeability may perceive greater cognitive difficulty, even though depression-related objective cognitive deficits may not be specific to inflammation- or leaky-gut-associated depression.

Short-term high-fat diet consumption impairs synaptic plasticity in the aged hippocampus via IL-1 signaling

More Americans are consuming diets higher in saturated fats and refined sugars than ever before. These trends could have serious consequences for the older population because high-fat diet (HFD) consumption, known to induce neuroinflammation, has been shown to accelerate and aggravate memory declines. We have previously demonstrated that short-term HFD consumption, which does not evoke obesity-related comorbidities, produced profound impairments to hippocampal-dependent memory in aged rats. These impairments were precipitated by increases in proinflammatory cytokines, primarily interleukin-1 beta (IL-1β). Here, we explored the extent to which short-term HFD consumption disrupts hippocampal synaptic plasticity, as measured by long-term potentiation (LTP), in young adult and aged rats. We demonstrated that (1) HFD disrupted late-phase LTP in the hippocampus of aged, but not young adult rats, (2) HFD did not disrupt early-phase LTP, and (3) blockade of the IL-1 receptor rescued L-LTP in aged HFD-fed rats. These findings suggest that hippocampal memory impairments in aged rats following HFD consumption occur through the deterioration of synaptic plasticity and that IL-1β is a critical driver of that deterioration.

Young adult and aged female rats are vulnerable to amygdala-dependent, but not hippocampus-dependent, memory impairment following short-term high-fat diet

Global populations are increasingly consuming diets high in saturated fats and refined carbohydrates, and such diets have been well-associated with heightened inflammation and neurological dysfunction. Notably, older individuals are particularly vulnerable to the impact of unhealthy diet on cognition, even after a single meal, and pre-clinical rodent studies have demonstrated that short-term consumption of high-fat diet (HFD) induces marked increases in neuroinflammation and cognitive impairment. Unfortunately though, to date, most studies on the topic of nutrition and cognition, especially in aging, have been performed only in male rodents. This is especially concerning given that older females are more vulnerable to develop certain memory deficits and/or severe memory-related pathologies than males. Thus, the aim of the present study was to determine the extent to which short-term HFD consumption impacts memory function and neuroinflammation in female rats. Young adult (3 months) and aged (20-22 months) female rats were fed HFD for 3 days. Using contextual fear conditioning, we found that HFD had no effect on long-term contextual memory (hippocampus-dependent) at either age, but impaired long-term auditory-cued memory (amygdala-dependent) regardless of age. Gene expression of Il-1β was markedly dysregulated in the amygdala, but not hippocampus, of both young and aged rats after 3 days of HFD. Interestingly, modulation of IL-1 signaling via central administration of the IL-1 receptor antagonist (which we have previously demonstrated to be protective in males) had no impact on memory function following the HFD in females. Investigation of the memory-associated gene Pacap and its receptor Pac1r revealed differential effects of HFD on their expression in the hippocampus and amygdala. Specifically, HFD induced increased expression of Pacap and Pac1r in the hippocampus, whereas decreased Pacap was observed in the amygdala. Collectively, these data suggest that both young adult and aged female rats are vulnerable to amygdala-dependent (but not hippocampus-dependent) memory impairments following short-term HFD consumption, and identify potential mechanisms related to IL-1β and PACAP signaling in these differential effects. Notably, these findings are strikingly different than those previously reported in male rats using the same diet regimen and behavioral paradigms, and highlight the importance of examining potential sex differences in the context of neuroimmune-associated cognitive dysfunction.

Preliminary evidence for developing safe and efficient fecal microbiota transplantation as potential treatment for aged related cognitive impairments

Background

Recent studies have reported that gut microbiota is closely associated with cognitive fuction. Fecal microbiota transplantation (FMT) may be a potential treatment for cognitive impairment, but its efficacy in patients with cognitive impairment is unknown.

Objectives

This study aimed to investigate the safety and efficacy of FMT for cognitive impairment treatment.

Methods

Five patients aged 54-80 years (three women) were enrolled in this single-arm clinical trial from July 2021 to May 2022. The Montreal Cognitive Assessment-B (MoCA-B), Activities of Daily Living (ADL), and the cognitive section of the Alzheimer's Disease Assessment Scale (ADAS-Cog) were assessed at days 0, 30, 60, 90, and 180. Additionally, stool and serum samples were obtained twice before FMT was administered and six months after the treatment. The structure of fecal microbiota was analyzed by 16S RNA gene sequencing. Serum samples were analyzed for metabolomics and lipopolysaccharide (LPS)-binding proteins by liquid chromatography-mass spectrometry and enzyme-linked immunosorbent assay, respectively. Safety was assessed based on adverse events, vital signs, and laboratory parameters during FMT and the follow-up period.

Results

The MoCA, ADL, and ADAS-Cog scores of patients with mild cognitive impairment (patients C and E) after FMT were improved or maintained compared with those before transplantation. However, patients with severe cognitive impairment (patients A, B, and D) had no worsening of cognitive scores. Fecal microbiota analysis showed that FMT changed the structure of gut microbiota. The results of serum metabolomics analysis suggested that there were significant changes in the serum metabolomics of patients after FMT, with 7 up-regulated and 28 down-regulated metabolites. 3b,12a-dihydroxy-5a-cholanoic acid, 25-acetylvulgaroside, deoxycholic acid, 2(R)-hydroxydocosanoic acid, and P-anisic acid increased, while bilirubin and other metabolites decreased. KEFF pathway analysis indicated that the main metabolic pathways were bile secretion and choline metabolism in cancer. No adverse effects were reported throughout the study.

Conclusions

In this pilot study, FMT could maintain and improve cognitive function in mild cognitive impairment by changing gut microbiota structure and affecting serum metabolomics. Fecal bacteria capsules were safe. However, further studies are needed to evaluate the safety and efficacy of fecal microbiota transplantation. ClinicalTrials.gov Identifier: CHiCTR2100043548.

Implication of saturated fats in the aetiology of childhood attention deficit/hyperactivity disorder - A narrative review

Attention Deficit/Hyperactivity Disorder (ADHD) is the most common mental health disorder in the paediatric population. ADHD is highly comorbid with obesity, and has also been associated with poor dietary patterns such as increased consumption of refined carbohydrates and saturated fats. Although ADHD in children was associated with high consumption of saturated fats, so far there has been no evidence-based attempt to integrate dietary strategies controlling for intake of saturated fats into the etiological framework of the disorder. Evidence from human studies and animal models has shown that diets high in saturated fats are detrimental for the development of dopaminergic neurocircuitries, synthesis of neurofactors (e.g. brain derived neurotrophic factor) and may promote brain inflammatory processes. Notably, animal models provide evidence that early life consumption of a high saturated fats diet may impair the development of central dopamine pathways. In the present paper, we review the impact of high saturated fats diets on neurobiological processes in human studies and animal models, and how these associations may be relevant to the neuropathophysiology of ADHD in children. The validation of this relationship and its underlying mechanisms through future investigative studies could have implications for the prevention or exacerbation of ADHD symptoms, improve the understanding of the pathogenesis of the disorder, and help design future dietary studies in patients with ADHD.