Location: Jean Mayer Human Nutrition Research Center On Aging
2015 Annual Report
Objectives
LAB NAME: Nutritional Immunology
1: Determine the impact and underlying mechanisms of obesity during pregnancy on newborn's life-long immune and inflammatory responses and resistance to infectious diseases in appropriate animal models.
1A. To investigate the impact of maternal obesity on immune function and influenza infection in young offspring.
1B. To determine the role of inflammatory, oxidative stress, and selected epigenetic markers that are critical for immune response to influenza and the higher susceptibility of obese mothers’ offspring to influenza infection.
1C. To determine the impact of maternal obesity on immune function and resistance to infection through the life cycle.
2: Determine the effect and mechanisms of food components such as fruits and vegetables or whole grains influence on, and their interaction with, age on immune and inflammatory responses and related diseases in both animal models and human studies.
2A: To determine the impact of increased consumption of F&V on prevention of key age-related biologic dysfunctions and pathologies in a suitable animal model.
2B: To determine the effect of consumption of an isocaloric diet rich in whole grains (WG)[compared to refined grains (RG)] on gut microbiota, and immune and inflammatory responses.
LAB NAME: Vascular Biology
1: Determine the effectiveness and underlying mechanisms of fruits/vegetables and Mediterranean style diets or their specific bioactive components in the prevention of atherosclerosis and survival using animal models of humans.
1A: Determine the effectiveness and underlying mechanisms of increased consumption F&V diets on prevention of atherosclerosis and survival using appropriate animal model of human atherosclerosis.
1B: Determine the effectiveness of natural bioactive polyphenols of foods and spices and their underlying mechanisms on prevention of atherosclerosis using appropriate animal models of human atherosclerosis.
2: Determine the efficacy of fruits/vegetables, avenanthramides from oats, and selected other bioactive compounds on alteration of microbiome and anti-microbial peptides, suppression of chronic inflammation of the GI tract, prevention of colon cancer and atherosclerosis in appropriate animal models. Under this objective, we will pursue the following sub-objectives:
2A: Determine the efficacy of bioactive phosphorylated tocopherols ('Tp) versus tocopherols on age-dependent decline of angiogenesis and suppression of atherosclerosis in vivo and ex-vivo.
2B: To determine the molecular signaling mechanisms by which 'TP induces angiogenesis.
3: Determine the effect of eight weeks consumption of an isocaloric diet enriched with whole grains (compared to refined grains) on gut microbiota, inflammatory and other risk predictors of atherosclerosis.
Approach
NUTRITIONAL IMMUNOLOGY: Aging is associated with dysregulation of immune and inflammatory responses, which contribute to several age-related diseases. Nutritional status including that during early life has been linked to health status of older adults, & nutritional interventions during different life stages including those during pregnancy are reported to have long-lasting effects on the health status of newborns. Long-term goal is to determine the underlying mechanisms of age-related immune & inflammatory dysregulation in order to develop nutritional interventions, which will prevent/reduce these alterations. [1] will determine the impact & underlying mechanisms of obesity during pregnancy on newborn's life-long immune & inflammatory responses & resistance to infectious diseases. To achieve this, we will use a diet-induced obesity mouse model and determine: 1) effect of maternal obesity on immune function and influenza infection in young offspring, 2) role of inflammatory, oxidative stress, and selected epigenetic markers in altered immune function and susceptibility to infection in offspring born to obese mothers, and 3) impact of maternal obesity on immune function and resistance to infection through the life cycle. [2] will determine the effect and mechanisms of food components such as fruits and vegetables or whole grains influence on, and their interaction with, age on immune and inflammatory responses and related diseases in both animal models and human studies. [2A], we will use a mouse model to determine whether the dietary supplementation with a variety of fruits and vegetables would impact health- and life-span through modulating oxidative stress, inflammation and the regulatory lipid, ceramide. [2B], we will conduct a dietary intervention trial in healthy middle-aged human participants to determine the effect of consumption of an isocaloric diet rich in whole grains compared to refined grains on gut microbiota, and immune and inflammatory responses. These studies will help develop effective strategies to improve health- and life-span of the aged through optimization of immune and inflammatory responses.
VASCULAR BIOLOGY: Determine survival rates, prevention of atherosclerosis, and underlying mechanism(s) in LDLr-/- young to old mice using freeze-dried fruits, vegetables and cereal grains in a high fat diet. Further, we will use C57/BL and LDLr-/- mice to determine the causal relationship & underlying mechanism(s) of specific bioactive food components (such as curcumin, resveratrol, avenanthramides, and their combinations) on inhibition of dyslipidemia, fatty liver, inflammation, metabolic disorders, & atherosclerosis resulting from consuming a diet high in fat and/or sweeteners like sucrose & high fructose corn syrup. We plan to establish the causal relationship of increased consumption of whole grains versus refined grains and their capacity to improve oxidative & antioxidant status as well as surrogate markers of cardiovascular disease. We will investigate potential molecular mechanisms by which alpha-Tocopheryl phosphate (alpha-TP), a natural derivative of alpha-T, induces angiogenesis in vitro & in an in vivo animal model.
Progress Report
This report documents research conducted under 2 projects in a Non-Assistance Cooperative Agreement between ARS and TUFTS UNIVERSITY. Additional details for the research are associated with projects 8050-51000-090-01S, Immunity Affected by Diet and Obesity and 8050-51000-090-02S, Fruits, Vegetables, and Related Bioactive Compounds and Prevention of Atherosclerosis, Obesity and Chronic Inflammation.
LAB: Nutritional Immunology - Adverse maternal conditions are associated with long-term metabolic dysregulation in the offspring. As obesity becomes epidemic worldwide, the negative impact of maternal obesity (MO) on offspring is an increasing health concern. MO has been linked to offspring immune dysfunction such as asthma, atopic disease, wheezing and respiratory infection. However, we know little about the effects of maternal obesity on immunity to viral challenges in the offspring. We have conducted a study to address this gap. We started with a pilot study using female C57BL/6 dam mice fed high fat (obesity) or low fat (lean control) diet to create a diet-induced obesity model, and then had them become pregnant and give birth to pups. However, we found significant cannibalism, which prevented us from continuing the study. To solve this, we used CD-1 mice and found no cannibalism but a similar response pattern to the dosing of influenza infection. We are currently continuing the pilot study to determine the optimal condition to detect immune and inflammatory responses after influenza infection.
Older adults have dysregulated immune and inflammatory responses. Diets rich in whole grains (WG) have been reported to decrease chronic inflammation and related diseases. However, no study has comprehensively investigated effect of WG vs. refined grain (RG) diet on gut microbiota, and immune and inflammatory responses when total energy intake is kept constant. We have conducted a study to determine effect of consuming high WG vs. RG diet for 8-wk on immune function, inflammation status, and gut microbiota in healthy middle- to older-aged adults (40-65 y). We have completed all participant recruitment, dietary intervention, and sample collection. All samples have been analyzed for gut bacteria, immune function and inflammatory responses. We are currently conducting sample analysis, data entry, and quality control.
We, as well as others, have shown that green tea catechin Epigallocatechin gallate (EGCG) has a protective effect on T cell-mediated autoimmune disease by inhibiting T cell proliferation. To further determine the molecular mechanisms of EGCG’s effect, we conducted an in vitro study using naïve CD4+ T cells from C57BL/6 mice. We found that EGCG inhibited stimulation-induced T cell division and cell cycle progression as evidenced by increased number of cells arrested in the early phase, decreased DNA synthesis activity, and retarded progression into the late phase. EGCG altered expression of several regulatory proteins involved in cell cycle indicating that the EGCG’s inhibitory effect on CD4+ T cells is mediated through changing the expression of proteins involved in regulation of cell cycle progression and division.
Common therapies for autoimmune inflammatory diseases have limited efficacy, often with substantial side effects. Dietary intervention may serve as an alternative, complementary approach. Naringenin, a flavonoid high in citrus fruits, particularly grapefruit, has been shown to have anti-inflammatory properties. We conducted a study to assess naringenin’s effect on T-cell mediated autoimmune disease using the experimental autoimmune encephalomyelitis (EAE), a rodent model for human multiple sclerosis. We found that mice fed naringenin (0.5% in diet) had delayed onset and attenuated symptoms of EAE, as well as reduced immune cell infiltration and pathological lesion (demyelination) in spinal cords. A study is underway to further investigate the immunopathological mechanisms underlying the observed effects.
To quantify more precisely the measurement errors associated with different methods for assessing diet and physical activity in large epidemiologic studies, we collaborated with the Harvard School of Public Health to conduct the Women’s Lifestyle Validation Study (WLVS) and the Men’s Lifestyle Validation Study (MLVS). Using multiple measurements, these studies evaluate the validity of various objective biomarkers as well as existing and new methods for assessing diet and physical activity. For the WLVS, all data collection and data cleaning are completed. The physical activity assessment is in progress. For MLVS, all lab work, except for nitrogen, is completed, and data produced are under review prior to delivery to Harvard. The nitrogen analysis is half done; the remainder is on hold pending availability of funds.
Although commensal bacteria are crucial in maintaining immune homeostasis of the intestine, little is known about commensal bacteria’s role in shaping the immune inductive function in a non-intestinal mucosal surface such as the lung. To address the gap in understanding the pulmonary microbiome as related to aging, we conducted a study to systematically look at the pulmonary microbiome of healthy older individuals through analysis of high-throughput 16SrDNA sequence data from broncho-alveolar lavage. In this prospective cohort study, we plan to enroll 15 young (21-30 y) and 15 older (65 y and older) participants with good physical performance. We have currently enrolled 2 young and 3 older participants; blood samples for certain immunological outcome measures have been analyzed.
LAB: Vascular Biology - Curcumin (Cur) project: Cur is a bioactive component of turmeric. Several health benefits have been attributed to the intake of Cur, including reduced risk of cancer, Alzheimer’s, diabetes and cardiovascular diseases. Cur through several mechanisms may modulate lipid metabolism and adiposity and atherosclerosis. Specific molecules such as “fatty acid binding protein" (FABP-4/aP2) and CD36 (a fatty acid transporter) in fat cells and immune cells (macrophages) are key players in foam cell formation in atherogenesis, an inflammatory disease of the arteries. Our earlier cell culture studies suggest that these effects of Cur might be mediated in part through suppression of these two molecules. Thus, our animal study aimed to further elucidate the impact of increasing doses of Cur on modulation of these mediators on high fat diet (HFD)-induced atherogenesis, inflammation, and fatty liver formation in LDL receptor knockout (Ldlr-/-) mouse model of human atherosclerosis. Cur dose-dependently increased the Cur conjugated metabolites in plasma, and through a series of mechanisms, “Cur or metabolites” exerted many biological and pharmacological effects in several organs. Cur abrogated the high fat diet’s adverse effect on fatty liver formation and abnormal lipid levels in the blood, both important factors in atherogenesis. However, Cur in higher doses had an adverse effect on atherogenesis. Low and medium doses of Cur used in this study were more effective at attenuating atherosclerosis than a higher dose. Also, Cur, through increasing cyclic adenosine monophosphate (cAMP) expression, induces hypolipidemic, antiatherogenic and thermogenic effects while the differential effects of Cur are dependent on the uptake and production of metabolites.
Vitamin E project: Supplementing C57/BL mice with adequate or high dose of alpha- tocopherol (a-T) or gamma tocopherol (g-T) significantly modulated gene expression in T cells of the immune system. Phosphorylated a-T and g-T activated vascular endothelial growth factor (VEGF), which induces angiogenesis, the formation of new blood vessels from existing ones. This proangiogenic activity of phosphorylated tocopherols may have several implications where vasculogenesis is an important process, e.g., wound healing and during the development/stabilization of placenta.
Fruits and vegetables project: Epidemiological studies have found that a high intake of fruits and vegetables (F&V) is associated with reduced risk of developing several conditions and diseases including obesity, diabetes, coronary heart disease (CHD), stroke, cancer; they could also contribute to longevity. However, little is known of the “causality” of F&V as a whole on such endpoints. We have identified the top 12 most commonly consumed fruits and 12 most commonly consumed vegetables according to the USDA database. We have lyophilized and measured their total polyphenol content. We will test the efficacy of lyophilized and powdered forms of these F&V on prevention of atherosclerosis in Ldlr-/- mice, a good mouse model of human hyperlipidemia and atherosclerosis.
Oats and atherosclerosis project: Oats in addition to containing beta-glucan, which reduces blood cholesterol levels, also contain unique polyphenols called avenanthramides (Avn), which we previously reported have anti-inflammatory properties. We tested inclusion of oats and malted oats in high fat diet-induced atherosclerosis in Ldlr-/- mice. We found that oats and avenathramides of oats effectively prevent atherosclerosis in these mice. We plan to test the efficacy of extracted and purified Avn on suppression of arterial inflammation in a high fat-fed mice.
Accomplishments
1. Vitamin E supplementation reduces morbidity and mortality from Streptococcus pneumoniae. During aging, the body’s immune function declines and becomes dysregulated. As such, aging increases the risk for developing lung infections like S. pneumoniae, one of the most common types of pneumonia in the elderly. ARS-funded researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, investigated whether vitamin E, an immune-modulating nutrient, can improve the age-associated decline in resistance to pneumococcal infection. They found that old mice were more susceptible to pneumococcal infection than young mice, and that feeding extra vitamin E to aged mice reversed their vulnerability to disease caused by this bacterium. In pursuing the working mechanism, they further found that this protective effect of vitamin E was associated with decreased inflammatory infiltration of neutrophils (a type of white blood cell that can produce damaging inflammatory materials) into the lungs. These results have significant implications for the health and quality of life for older adults through reducing the risk of lung infections, a major cause of morbidity and mortality in elderly.
2. Curcumin alters transport of fats. Curcumin is a naturally occurring plant-based chemical derived from the root of the spice turmeric, which is traditionally used in the prevention and treatment of many diseases in Asian countries. Despite its low bioavailability, it lowers the levels of lipids in plasma and reduces obesity, which is known to be a key contributor to the development of several diseases. ARS-funded researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, analyzed the molecular mechanisms by which curcumin may influence the plasma and tissue lipid levels in mice. They examined the accumulation and metabolism of fat in different cells by investigating the relationship of a transporter molecule called CD36 to another protein called cCAMP (cyclic adenosine monophosphate protein). Understanding the biological action of curcumin and its ability to alter these energy and transporter molecules would help us develop a method to eliminate excess body fat more efficiently in overweight and obese individuals.
3. Vitamin E phosphate supports formation of new blood vessels. It has been known for several decades that vitamin E deficiency in mice causes fetal resorption, which is a condition in which a fetus dies in the womb, disintegrates and then is reabsorbed internally. The mechanism for the occurrence of this abnormality is not well understood. In particular it is not known if this is a direct effect of vitamin E or its metabolite. ARS-funded researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, reported that phosphorylated or chemically modified forms of vitamin E, but not non-phosphorylated or naturally-occurring, free forms of vitamin E stimulate genes in the cells of arteries to produce a protein called “vascular endothelial growth factor” (VEGF). This protein stimulates “angiogenesis,” which is the formation of new blood vessels from existing ones and a process important in fetal growth. Their study indicates that the phosphorylated form of vitamin E might be a necessary factor in the normal development of the placenta as well as the prevention of fetal resorption. This observation suggests that consumption of a phosphorylated form of vitamin E during pregnancy might support healthy development of the placenta, the fetus and all body tissues that need new blood vessel formation.
