Week 7 readings summary Flashcards
2 immune response pathways
innate pathway
adaptive pathway
what is the innate pathway?
Innate immunity is a rapid but nonspecific response system that is initiated by a broad range of pathogen molecules
macrophage expression of scavenger receptors recognize pathogen molecules and stimulate phagocytosis and macrophage secretion of pro-inflammatory molecules such as reactive oxygen species and a variety of cytokines
what is the adaptive pathway?
Adaptive immunity is a slower and more focused response system that recognizes specific pathogen molecules and is highly antigen dependent.
why do we rely on acute inflammatory response?
to fend off acute stressors such as infection
potential mechanisms of chronic inflammation in obese individuals?
lots of adipose tissue (source on inflammatory cytokine secretion)
endothelial dysfunction (resulting in vascular wall damage and release of inflammatory cytokines)
lower o2 levels (triggers recruitment of inflammatory cells)
what is hypoxia associated with?
hypoxia was associated with an increased macrophage infiltration, an increased expression of pro-inflammatory genes and a decreased expression of adiponectin, an anti-inflammatory protein, in adipose tissue
why may enlarged adipose tissue become hypoxic in obese individuals?
they have - increase angiogenesis - altered VEGF gene expression - vasoconstriction - decreased adipose tissue capillary density elevated mononuclear cell expression
effects of exercise training on chronic inflammation?
Observational studies
Findings from a number of cross-sectional studies support significant inverse relationships between physical activity and levels of inflammation in men a
Findings are more consistent for CRP than for other biomarkers
effects of exercise training on chronic inflammation?
Intervention studies in healthy individuals
Mixed findings - most reported that exercise training, as compared with control, significantly reduced at least one inflammatory marker, such as CRP, IL-6, or IL-18
While the length of exercise training seems to be important, baseline body composition, the specific inflammatory biomarkers being studied and the length of time to ‘wash out’ the effects of the last exercise session on inflammatory biomarkers may also influence study results
effects of exercise training on chronic inflammation?
Intervention studies in diseased individuals
Similar to findings in healthy individuals, exercise training was effective in lowering chronic inflammation in several, but not all, studies conducted in adults with existing diseases
In addition to exercise type, length of exercise training, baseline obesity status, selection of inflammatory markers, the type of disease and its influence on baseline inflammation status, exercise compliance and influence of the last exercise session on inflammatory biomarkers may be major factors bearing on the extent to which a training effect is observed
effects of exercise training on chronic inflammation
aerobic/resistance exercise and weight conditions
Recently, several randomized controlled studies support that resistance exercise alone also is effective in reducing chronic inflammation, in both healthy and diseased individuals
Findings from a recent study support more benefits from combined aerobic and resistance exercise than aerobic exercise alone in reducing chronic inflammation
Other studies did not see these effects
6 months of caloric restriction plus aerobic exercise training, compared with caloric restriction alone, is more effective in reducing circulating levels of inflammatory biomarkers in overweight or obese women
how does muscle tissue affect inflammation
Increased release of IL-6 in skeletal muscle
Although the increase in muscle IL-6 release is transient, it could increase release of IL-10 and IL-1 receptor antagonist (IL-1RA) by leukocytes to act as anti-inflammatory cytokines
In response to acute exercise, cytokine expression and/or release from adipose tissue and peripheral mononuclear cells are also elevated
Elevations in IL-6 levels do not occur with low to moderate-intensity exercise
how does adipose tissue affect chronic inflammation?
Current evidence supports that exercise training decreased expression of pro-inflammatory cytokines and increased expression of anti-inflammatory cytokines in visceral adipose tissue
compared to a non-exercise group, 9 weeks of exercise training increased the density of endothelial cells in visceral (epidydimal) adipose tissue and increased the gene expression of VEGF
Exercise training reduces vasoconstriction factors
increases adipose tissue blood supply in animals
how does endothelial cells affect chronic inflammation?
exercise training may increase the number of endothelial progenitor cells
regular exercise increases blood flow and laminar shear stress, and reduces endothelial expression and the release of adhesion molecules
What are endothelial progenitor cells?
circulating bone marrow derived stem cells that can differentiate into endothelial cells
