Recipient Organization
COLORADO STATE UNIVERSITY
(N/A)
FORT COLLINS,CO 80523
Performing Department
Food Science & Human Nutrition
Non Technical Summary
Heart disease is the leading worldwide cause of death among women and men. Hence, interventions that decrease risk factors that exacerbate harmful heart outcomes may be useful in preventing or treating diseases such as cardiovascular disease (CVD). A cluster of metabolic abnormalities/conditions characterized to increase the occurrence of CVD include abdominal adiposity, dyslipidemia, inflammatory dysregulation, increased blood pressure, and insulin resistance. The previous characteristics are also linked to the progression of type-2-diabetes, hence these harmful factors are collectively termed cardiometabolic risks. Research demonstrates that cardiometabolic risks increase linearly with age with a prevalence of ~7% in years 20-29 relative to ~45% in those greater than 60 years of age.Food choices play a fundamental role in reducing the prevalence of cardiometabolic risks. It is estimated that over 30% of deaths could be prevented by dietary changes that include increased consumption of plant-based foods. Plant foods offer different proportions of fiber, essential micronutrients, vitamins and minerals. Plant foods are also a rich source of bioactive compounds, i.e. phytochemicals, with potential to promote health throughout the lifespan by reducing the risk of age and lifestyle-induced disease.In the United States, potatoes are the top vegetable crop consumed by humans. Consistent with this, potatoes have the third highest commodity ranking among vegetables. For these reasons, improving the nutritional quality of potatoes consumed and promoting their consumption represents a promising means for improving human health. In addition, validating and molecular characterization of the health properties of these potatoes can be used to establish a breeding program that provides potato varieties that improve economic sustainability for growers, distributers, and produce sellers.To validate the health qualities of the Purple Majesty we propose to investigate our aims in a genetic mouse model of obesity. With this model we can determine the degree to which Purple Majesty potatoes can reverse factors that lead to cardiometabolic risks. The genetic obese mouse (Lep ob/ob; Jackson laboratory, Stock # 000632) of interest is characterized to have several factors that lead to cardiometabolic risks including excessive fat, high circulating blood lipids, pro-inflammation, increased blood pressure, and insulin resistance. Using numerous measures including glucose tolerance test, insulin concentration, blood lipid levels, inflammatory cytokine assays, flow cytometry, microbiota characterization and endothelial function we will characterize specifically how Purple Majesty intake and specific fractioned bioactives improve health.Ultimately with this project we intend to demonstrate that bioactive components in the Purple Majesty potato will synergistically counteract cardiometabolic risks factors. Hence, the goal of this proposal is to examine Purple Majesty potato consumption in attenuating cardiometabolic risk. For society, this will give proof that potato is a healthy vegetable option because of the bioactive compounds contained within.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
Our central hypothesis is that Purple Majesty powder (added to purified diet (AIN-93M)) compared to a diet with no treatment will decrease cardiometabolic risks such a high blood pressure, pro-inflammation and insulin resistance. Our hypothesis will be tested using the below specific aims:Specific Aim 1: To examine if Purple Majesty powder can decrease blood vessel dysfunction, improve gastrointestinal health, decreased pro-inflammation in tissues and blood as well as improve glucose tolerance.Specific Aim 2: Determine the relative contribution of the fractioned bioactive chlorogenic acid (CGA) from Purple Majesty potatoes toward attenuation of cardiometabolic risks.
Project Methods
Glucose Tolerance Test - This will be measured as an indication of improved insulin sensitivity. Blood glucose will be determined from tail vein (Freestyle Lite Glucometer; Abbott, Abbott Park, IL). Mice will have basal blood collected then receive a 1.5 g/kg dextrose injection (ip) before tail vein blood samples are again collected at 15, 30, 45, 60 and 120 min post-injection. Insulin response to glucose injection will also be evaluated.Adipose tissue mass - Adipose tissue mass will be recorded to examine if health benefits may result from decreased adiposity. Visceral and subcutaneous adipose depots will be weighed and collected for immune cell analysis.Gastrointestinal Health - Evidence supports that the gastrointestinal tract plays a principal role in the development of metabolic disorders. This is likely due to the interaction between the gut microbiome and immune cells within the gastrointestinal. Indeed, the gastrointestinal tract is estimated to constitutively engage ~70% of total body immune cells [22] for immunologic defense against harmful pathogens [23, 24] and maintenance of homeostasis. Consequently, this permits gastrointestinal health to have considerable influence on systemic immune function. Antioxidant and anti-inflammatory benefits of the Purple Majesty will likely greatly influence the gastrointestinal tract. As such the following measures will be performed:Microbiota characterization. Cecal material will be collected at termination and DNA extracted using the QiaAMP DNA Stool Mini Kit (Qiagen). 2 x 300bp paired-end sequencing libraries of the V4 region of the 16s rRNA gene will be constructed by following the Schloss MiSeq Wet Lab SOP followed by sequencing on an Illumina MiSeq. All 16S rRNA gene sequences will be filtered for and processed with the newest version of the open source bioinformatics tool mothur[25]. Sequence reads will be trimmed (maxambig=0, maxlength=275), aligned with SILVA sequence alignment, filtered and checked for chimeras, and OTUs will be classified based on the mothur implementation of the Greengenes database.In vivo intestinal barrier integrity. Prior to termination, animals will be fasted for 6 hours and orally administered fluorescein isothiocyanate (FITC)-dextran (400 mg/kg BW). Tail vein blood samples will be collected hourly for 4 hours and FITC-dextran concentrations in diluted plasma will be determined with a fluorescent spectrophotometer.Intestinal barrier function and inflammation. Tight junction proteins maintain the integrity of the intestinal epithelia by forming transmembrane spans between adjacent cells that regulate flux across the intestinal barrier [26]. Fixed ileum and colonic tissue sections will be used to assess measures of intestinal function by immune-staining and visualization of tight junction proteins occludin and zonulin-1.Intestine immune cell alterations. These general methods are discussed in the immune section below.Immune Cell Function - In addition to intestines (jejunum and ileum), visceral adipose tissue and lymph nodes will be collected to evaluate immunity. Immune homeostasis is sustained primarily by the lymphatic system, which serves as the conduit for immune cells and is fundamental for protective immune responses. The lymph nodes of the lymphatic system serve as immune barriers in and between tissues. In particular, the visceral lymph node serves as a conduit that continuously surveys and monitors exposure of the small intestine to metabolites, commensal bacteria and potentially harmful pathogens [27, 28]. Data supports that intestinal immunity and systemic immune health is predominately mediated by immune cells incase within the visceral lymph node [29]. This node, however, is embedded in and receives effluent from visceral adipose depot. Therefore, an evaluation of immune health should include intestines, visceral adipose tissue and the visceral lymph node, which is the nexus of the intra-abdominal cavity. This will accomplished with flow cytometry using antibodies from eBioscience to mark for T cells, T helper cell, B cells, cytotoxic T cells, regulatory T cells, myeloid suppressor cells, natural killers, dendritic cells and macrophages (eBioscience, San Diego, CA).To compliment flow cytometry analysis multiplex and mesoscale panels will be designed to evaluate adipokines and cytokines such as, IL-1b, leptin, adiponectin, resistin, TNFα, IL-13, IL-6, IL-5, IL-7, KCGRO, Monocyte Chemoattractant Protein-1 (MCP-1), plasminogen activator inhibitor (PAI).Cardiovascular Health - Phytochemicals identified in Purple Majesty are also proposed to play a beneficial role in cardiovascular health, hence blood vessel function will be evaluated.Reversal of Blood Vessel Dysfunction. Two parameters of blood vessel dysfunction will be assessed, arterial stiffness and endothelial dysfunction. Prior to termination, mice will be anesthetized and arterial stiffness will be determined by pulse wave velocity as previously described [30]. Following termination, endothelial function will be determined in mesenteric and carotid arteries as previously described by our group [31].