Integrative Review of Dietary Choice Revealed by fMRI: Considerations for Obesity Prevention and Weight-Loss Education.

BACKGROUND: Emerging findings from neuroimaging studies investigating brain activity associated with dietary behavior are illuminating the interaction of biological and behavioral mechanisms that have implications for obesity prevention. Globally, A total of 1.9 billion adults are overweight, and 650 million are obese. Obesity and being overweight are major risk factors for chronic illness and death. Behaviorally based health interventions have had limited success in curbing the obesity epidemic. Greater understanding of brain responses to food cues will contribute to new knowledge and shape public health efforts in obesity prevention. However, an integration of this knowledge for obesity prevention education has not been published. AIMS: This study links evidence generated from brain activation studies generated in response to diet and food images and highlights educational recommendations for nurses engaged in obesity prevention and weight-loss education. METHODS: An integrative review of the literature was conducted using the MeSH keywords "magnetic resonance imaging," "diet," and "food images" in PubMed, MEDLINE Complete, CINAHL, and Cochrane databases from their first appearance in 2006 through March 2018. Studies published in English and using functional magnetic resonance imaging to measure brain response to diet, and food images were initially identified. Animal models, those whose primary focus was a specific disease, and intervention studies were excluded. RESULTS: Of 159 studies identified, 26 met inclusion criteria. Findings from neuroimaging studies may help explain the relationship between brain mechanisms and behavioral aspects of dietary choice and inform patient education in obesity prevention. Awareness of this evidence is applicable to nursing education efforts. This review contributes several recommendations that should be considered by nurses providing individualized weight-loss education. LINKING EVIDENCE TO ACTION: Nurses engaged in patient education for obesity prevention should consider personalized interventions that cultivate internal awareness for dietary adherence, self-care, exercise, hydration, and mood state; avoid using caloric deprivation approaches, such as skipping breakfast, for weight-loss interventions; and note the importance of individualized obesity prevention and weight-loss education.

Brain activation and affective judgements in response to personal dietary images: An fMRI preliminary study.

Emerging evidence from functional magnetic resonance imaging (fMRI) brain activation studies associated with dietary behavior reveals significant interaction of biological and behavioral mechanisms in response to visualized food stimuli. Because food intake is influenced by neurosensory stimulation and memory cues, personalized food images may be useful in prompting appropriate affective responses to food intake, which may subsequently lead to healthier eating behaviors. The current study used a cross-sectional mixed methods approach to explore neural responses and self-perceptions of eating behavior during review of personalized food images. A sample of college students (N = 16; 9 females; M age = 21.44) used cell-phone cameras and an online dietary tracking website to collect and report three days of diet. Within 2-3 weeks of completing dietary tracking activity, participants underwent an fMRI scan while reviewing recorded personal images and text descriptions of their diet. They also responded to three questions related to memory for the food items and future eating intentions. Post-scan interviews explored how participants felt after reviewing personal food images and the possible impact that such review might have on future food choices. Whole brain analyses suggested, compared to a written dietary record, that the visualization of personal images of diet evoked greater brain activation in memory regions (e.g., superior frontal gyrus) along with mediating emotion (e.g., thalamus, putamen, anterior cingulate cortex), imagery and executive functions (e.g., inferior orbitofrontal gyrus, fusiform, and parietal lobe). This study offers preliminary support for the use of personal food images to strengthen dietary monitoring.

Isolation and characterisation of human pulmonary microvascular endothelial cells from patients with severe emphysema.

BACKGROUND: Loss of the pulmonary microvasculature in the pathogenesis of emphysema has been put forward as a credible alternative to the classical inflammatory cell driven proteolysis hypothesis. Mechanistic studies in this area have to date employed animal models, immortalised cell lines, primary endothelial cells isolated from large pulmonary arteries and non-pulmonary tissues and normal human pulmonary microvascular endothelial cells. Although these studies have increased our understanding of endothelial cell function, their relevance to mechanisms in emphysema is questionable. Here we report a successful technique to isolate and characterise primary cultures of pulmonary microvascular endothelial cells from individuals with severe emphysema. METHODS: A lobe of emphysematous lung tissue removed at the time of lung transplantation surgery was obtained from 14 patients with severe end-stage disease. The pleura, large airways and large blood vessels were excised and contaminating macrophages and neutrophils flushed from the peripheral lung tissue before digestion with collagenase. Endothelial cells were purified from the cell mixture via selection with CD31 and UEA-1 magnetic beads and characterised by confocal microscopy and flow cytometry. RESULTS: Successful isolation was achieved from 10 (71%) of 14 emphysematous lungs. Endothelial cells exhibited a classical cobblestone morphology with high expression of endothelial cell markers (CD31) and low expression of mesenchymal markers (CD90, αSMA and fibronectin). E-selectin (CD62E) was inducible in a proportion of the endothelial cells following stimulation with TNFα, confirming that these cells were of microvascular origin. CONCLUSIONS: Emphysematous lungs removed at the time of transplantation can yield large numbers of pulmonary microvasculature endothelial cells of high purity. These cells provide a valuable research tool to investigate cellular mechanisms in the pulmonary microvasculature relevant to the pathogenesis of emphysema.

Alveolar macrophage-mediated elastolysis: roles of matrix metalloproteinases, cysteine, and serine proteases.

Chronic obstructive pulmonary disease (COPD) is a common lung disease with cigarette smoking as the major etiological factor, but only 15% of smokers develop COPD. Destruction of lung elastin observed in COPD is mediated by many enzymes, including cysteine, serine, and matrix metalloproteinases (MMP). The contribution of these enzymes to the lung elastolytic load, released from alveolar macrophages collected from nonsmokers, healthy smokers, and COPD patients, was examined by radiolabeled elastin as substrate in the presence of specific enzyme inhibitors. The activity of MMP was further examined by zymography and Western blotting. COPD macrophages degraded more elastin than either of the other groups. Elastolysis was greatest in the initial 24 h. Through the 72-h culture period, the contribution to elastolysis of serine elastases decreased, MMP increased, and cysteine elastases remained constant. The increased release of elastolytic enzymes in COPD subjects may explain why some smokers develop COPD. This difference may be due to unknown susceptibility factors. Serine proteases play a significant role; however, other enzymes, particularly the MMP, deserve further investigation.