102 Clinical Trials for Various Conditions
To evaluate the validity of a continuous oral sip-feeding method of stable isotope tracer for the evaluation of whole-body protein metabolism in response to two different doses of an EAA/whey protein supplement (Low=6.3g and High=12.6g). Results will be compared to those previously determined by constant infusion with the same EAA/whey supplement.
The anabolic action of 'fast' whey protein on the regulation of postprandial muscle protein synthesis has been established to be short-lived in healthy young adults. Our aim was assess the time course of anabolic signaling events and stimulation of muscle protein synthesis rates (MPS) after ingestion of a food source that represents a more typical meal-induced pattern of aminoacidemia, namely milk protein concentrate, in healthy young males.
Sarcopenia, a progressive loss of muscle mass, strength and function, is an inevitable natural process of aging. While it may be impossible to completely reverse the progress of sarcopenia, it is well established that intake of dietary protein through essential amino acids (EAAs) and whey protein increases anabolic response. The current study will test if a specially formulated mixture of EAAs and whey protein can maximally stimulate anabolic responses at the levels of whole body and muscle compared to whey protein alone.
ALS, also known as "Lou Gehrig's" disease, is a neurodegenerative disease which is fatal. Treatment for ALS is limited and currently consists of primary symptom relief or support. In addition, time from diagnosis to death averages 3-5 years. New Biotic, LLC has submitted an Orphan Drug Designation Application for an investigational probiotic and have indicated the need for more study of this orphaned drug in ALS patients.
To determine the rate and mechanisms of skeletal muscle protein synthesis and breakdown in cirrhotic patients by using multiple tracers and single muscle biopsies.
This study is being done to understand metformin's mechanisms of action regarding glucose production, protein metabolism, and mitochondrial function.
Obesity is associated with reduced adenosine triphosphate (ATP) turnover in skeletal muscle, a condition that can impair muscle metabolism. The proposed research will discover mechanisms responsible for decreased content in mitochondrial proteins as well as in protein β-F1-ATPase, which is directly responsible for ATP assembly, in the muscle of obese individuals. This research will further examine the effectiveness of interventions, such as increased plasma amino acid availability and exercise, to increase the rate of production of mitochondrial proteins as well as that of β-F1-ATPase in the muscle of obese individuals. The findings will help to develop appropriate interventions to improve muscle ATP turnover and metabolism in obese people.
Inflammatory bowel disease, which includes both Crohn's disease and ulcerative colitis, is a disease of the gastrointestinal tract leading to symptoms of abdominal pain, diarrhea, and growth disturbance. Crohn's disease is a chronic inflammatory process that may affect any part of the gastrointestinal tract, whereas ulcerative colitis is typically present only in the colon. Children with inflammatory bowel disease frequently suffer from disturbances in growth, which may continue into adulthood and result in altered growth outcomes. The metabolic response to inflammatory bowel disease, including increased protein breakdown and decreased protein synthesis may play a significant role in the resulting malnutrition and growth failure from which children with inflammatory bowel disease suffer. The purpose of this study is to compare the rates of protein synthesis within the mucosal lining of the gastrointestinal tract in children Crohn's disease or ulcerative colitis to children who have normal endoscopic examinations. By comparing children with inflammatory bowel disease to normal children, we can begin to determine how alterations in protein metabolism within the lining of the gastrointestinal tract affect whole body protein metabolism, and its consequent effects on growth. In those patients diagnosed with Crohn's disease or ulcerative colitis, a follow-up study will be conducted two weeks following the initiation of steroid therapy to determine its effects on protein metabolism. We hypothesize that children with active inflammatory bowel disease will have increased rates of protein synthesis in the lining of the gastrointestinal tract than patients who have normal endoscopy, and that increases in protein breakdown and protein synthesis will be improved following steroid therapy in children with newly diagnosed inflammatory bowel disease.
Muscle catabolism is a major problem in cancer patients undergoing surgery as it negatively affects post-operative recovery. Recent evidence exists that protein metabolic changes are already apparent in cancer before muscle wasting is being present. In line, patients with breast cancer, generally characterized by a normal nutritional status, were recently found to be arginine deficient. Arginine deficiency in cancer can be explained by: 1) Reduced arginine availability, due to exhaustion of endogenous (muscle) sources of arginine 2) Enhanced arginine catabolism, due to conversion of arginine by arginase, which is abundant in tumors. Protein is the most important endogenous source of arginine. Arginine deficiency will lead to a negative feedback loop in cachexia by promoting protein breakdown in an attempt to restore plasma arginine levels. We hypothesize that pre-operative arginine supplementation in breast cancer patients diminishes the occurrence of muscle wasting after surgery by 1) normalizing arginine availability pre-operatively, resulting in conservation of protein, 2) diminishing the catabolic effects of surgery by supplying exogenous arginine for the post-operative response, 3) enhancing the anabolic capacity to feeding through supplying substrate for protein synthesis.
The purpose of the proposed study is to investigate the effects of rhGH treatment on glucose, protein and fat metabolism in GHD children. Specifically, the investigators will measure the rates of glucose production, gluconeogenesis, glycogenolysis, insulin sensitivity and glucagon response before and after treatment with rhGH. In addition, the investigators will study changes in protein and fat metabolism pre and post rhGH therapy in children with GHD. The findings in the GHD children will be compared to those of a control group of age and sex matched healthy children. Hypotheses: H1- The fraction of glucose derived from gluconeogenesis is decreased and that from glycogenolysis is increased in the post-absorptive state in untreated GHD children when compared to healthy children. H2- Treatment with rhGH will not change the overall glucose turnover but will normalize the abnormal partitioning of gluconeogenesis and glycogenolysis in GHD children. H3- GH replacement will reduce urea production and increase estimates of protein synthesis, thus optimizing the availability of amino acids for growth. H4- Untreated children with GHD after an overnight fast will have an increased glucagon challenge response that will decrease after 8 weeks of treatment with rhGH. Specific Aims: In healthy and newly diagnosed GHD children the investigators will: 1. Measure the Glucose Production Rate (GPR) 2. Determine the fraction of glucose derived from gluconeogenesis and glycogenolysis 3. Estimate insulin sensitivity 4. Measure proteolysis and protein oxidation 5. Determine glucagon challenge response after an overnight fast. The above-mentioned parameters will be re-evaluated in the children with GHD after 8 weeks of rhGH therapy.
Peanuts are considered a functional food and regular consumption is associated with positive health effects. Protein is the second most common nutrient in peanuts after fat. The protein digestibility of peanuts is similar to that of animal protein, and the limiting amino acids in peanuts vary based on the study and are suggested to be lysine, methionine, or threonine. Defining the reduced responsiveness of various dietary proteins to induce anabolism in older adults is critical for preventing and attenuating physical and cognitive health decline.
The researchers overall objective is to determine whether plant and animal protein based proteins affect the anabolic responses across aging populations differently due to specific changes in the essential amino acids (EAA) and non-essential amino acids (NEAA) kinetic responses. The researchers central hypothesis is that a high EAA to NEAA ratio in a protein meal is related to higher anabolic response to the meal. The researchers also hypothesize that the type of NEAA in a protein meal also affects the anabolic capacity of the meal. The researchers rationale is that finding the amino acid composition of a meal that will maximally induce protein anabolism will guide novel nutritional approaches to prevent and treat sarcopenia, thereby reducing both overall economic burden and improving individual patient outcomes.
Previous studies suggest that changes in metabolism due to the effects of aging might serve as a potential for therapeutic agents. The investigating lab developed a pulse method combining multiple stable isotopes to study multiple metabolic pathways in the same individual simultaneously. By measuring whole-body metabolism in a large group of older adults, the investigators may be able to unravel age-related deterioration in protein turnover (synthesis and breakdown) that contributes to impaired functional capacity. Metabolic profiles could explain differences in pathways in the aging process with special interest in metabolism of amino acids as they have been associated with aging-related disorders.
Several of the investigator's recent studies have shown that all dietary proteins are not equal when it comes to making proteins in human bodies. Generally, foods made from animal muscle tissue are much more efficient at making new proteins in the body that those from plant sources. This study will measure the amount of protein growth in participants after consuming either one beef patty, one vegi-burger, or two vegi-burgers. By using stable isotope infusions and collecting blood and leg muscle samples, the investigator's lab can determine the rate of muscle metabolism that happens after a participant eats a protein-containing food. The investigator wants to determine if the vegi-burger is as efficient as the beef patty at creating proteins in a participants. The investigator will measure this metabolism over a 10-hour period, with the food being eaten at the 4 hour mark. The investigator plans to perform this procedure on up to 8 participants per food option (24 total).
Dietary protein is digested in the stomach and intestines to smaller peptides and 20 individual amino acids which, when absorbed by the gut into circulation and taken up by skeletal muscle, help stimulate muscle protein synthesis (MPS). Amino acids also provide the building blocks for muscle proteins that contribute to lean mass gains and increased strength following resistance exercise. Therefore, strategies to efficiently maximize amino acid exposure without overconsumption are warranted. Oral enzyme supplementation is a candidate approach to optimize amino acid absorption from dietary protein and protein supplements. Microbial proteases, approved for dietary supplement use, can theoretically speed up the conversion of protein and peptides to amino acids. Protease supplements have been marketed to promote muscle strength by optimizing amino acid absorption, however the clinical evidence is limited. This work will support that ingestion of protease supplements with a meal can allow individuals to more efficiently increase amino acid levels from a given amount of dietary protein.
Skeletal muscle quality is an important determinant of exercise performance and overall health. It is vital for not just movement, but also metabolizing nutrients. Protein from the diet can promote muscle protein synthesis for muscle recovery and growth. More importantly, doing so shifts net protein balance positively (e.g. protein synthesis is greater than protein breakdown) and promotes greater rates of muscle protein turnover. Leucine is an amino acid required to build muscle, but it also acts as a signaling molecule informing the muscle to start protein synthesis. Before reaching skeletal muscle, dietary protein is digested into small peptides and free amino acids. Rate of absorption from the intestine to the blood stream is significantly faster for peptides compared to amino acids. As amino acid availability in the blood is a precursor for muscle protein synthesis, our objective is to determine if the different absorption rates between free amino acid and peptides influence muscle protein synthetic and breakdown rates.
The investigators will examine the effects of a given amount of a protein food source such as pork, mixed nuts, and tofu on anabolic response at the whole body and muscle levels in young, healthy adults.
The investigators will determine effects of different sources of protein on whole-body net protein synthesis and muscle protein synthesis in young healthy participants.
Background: - Glucocorticoids are primary stress response hormones released from the adrenal gland when an individual is under stress. Chronic or ongoing elevation of these hormones due to prolonged stress or medical treatments can have numerous harmful effects. Researchers are interested in learning more about how these hormones affect cell growth, development, and death. To study glucocorticoid hormones, researchers plan to use the medication dexamethasone, which affects the parts of cells that respond to glucocorticoid hormones. Objectives: - To study glucocorticoid stress hormones in healthy individuals before and after receiving dexamethasone. Eligibility: * Healthy individuals at least 18 years of age. * Participants must not be using certain medications that may affect the dexamethasone test, including hormonal contraception, steroid-based drugs, and some antidepressants. Design: * This study will require an initial screening visit and a second study visit. The visits are estimated to require about 1 to 2 hours of participation over a period of up to 14 days. * Participants will be screened at visit 1 with a full physical examination and medical history, and an initial blood sample for testing. * For visit 2, participants will be asked to abstain from all food and drinks except for water for 12 hours before the appointment, and will take one tablet of dexamethasone 9 hours before the appointment. * Participants will have a second blood sample taken during visit 2, and will receive a snack after the blood is drawn.
The metabolic response to ulcerative colitis, including increased proteolysis and lipolysis and changes in energy expenditure, plays a significant role in the resulting malnutrition from which these patients suffer. Tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, has been found to be elevated in children with ulcerative colitis. TNF-alpha has been incriminated in the mechanism of weight loss in many different chronic diseases, and causes net protein and lipid catabolism. Anti-TNF-alpha antibody (infliximab) has been proven to be an effective therapy for ulcerative colitis. The purpose of this study is to determine changes in protein and lipid metabolism, as well as resting energy expenditure, before and after therapy with anti-TNF-alpha antibody (infliximab) in children with ulcerative colitis. Performing this study will better define the changes in nutrition status observed in these children following remission of active ulcerative colitis, and potentially lead to changes in medical and nutritional management of these children
The metabolic response to Crohn's disease, including increased proteolysis and lipolysis and changes in energy expenditure, plays a significant role in the resulting malnutrition from which these patients suffer. Tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, has been found to be elevated in children with ulcerative colitis. TNF-alpha has been incriminated in the mechanism of weight loss in many different chronic diseases, and causes net protein and lipid catabolism. Anti-TNF-alpha antibody (infliximab) has been proven to be an effective therapy for ulcerative colitis. The purpose of this study is to compare changes in protein and lipid metabolism, as well as resting energy expenditure, before and after therapy with anti-TNF-alpha antibody (infliximab) or corticosteroids in children with recurrent Crohn's disease. Performing this study will better define the changes in nutrition status observed in these children following remission of active Crohn's disease, and potentially lead to changes in medical and nutritional management of these children.
A goal of this study is to use a novel methodology to determine whether insulin resistance in women with polycystic ovary syndrome (PCOS) is related to the accumulation of proteins with modifications. This could lead to future research to determine if these modifications interfere with their proper function. Additionally, the investigators will determine how protein quality is affected by exercise training. Aerobic exercise enhances the endogenous oxidant buffering systems which may minimize oxidative damage to proteins. The investigators propose that aerobic exercise minimizes the accrual of modified proteins by increasing the synthesis of new proteins, but also by increasing the degradation and removal of old and damaged proteins. Based on our previous studies the investigators observed that insulin affects plasma protein synthesis and aerobic exercise improves insulin sensitivity not only in muscle but also in liver. The investigators therefore propose that aerobic exercise and related increase in insulin sensitivity (and decline in insulin levels) will reduce accumulation of old and modified skeletal muscle and plasma proteins leading to improved function.
Loss of muscle protein is generally a central component of weight loss in Chronic Obstructive Pulmonary Disease (COPD) patients. Gains in muscle mass are difficult to achieve in COPD unless specific metabolic abnormalities are targeted. The investigators recently observed that alterations in protein metabolism are present in normal weight COPD patients. Elevated levels of protein synthesis and breakdown rates were found in this COPD group indicating that alterations are already present before muscle wasting occurs. The investigators recently observed that in order to enhance protein anabolism, manipulation of the composition of proteins and amino acids in nutrition is required in normal-weight COPD. Intake of casein protein resulted into significant protein anabolism in these patients. The anabolic response to casein protein was even higher than after whey protein intake. A substantial number of COPD patients, underweight as well as normal weight to obese, is characterized by an increased inflammatory response. This group failed to respond to nutritional therapy. Previous experimental research and clinical studies in cachectic conditions (mostly malignancy) indicate that polyunsaturated fatty acids (PUFA) are able to attenuate protein degradation by improving the anabolic response to feeding and by decreasing the acute phase response. Eicosapentaenoic acid (EPA) (in combination with docosahexaenoic acid (DHA)) has been shown to effectively inhibit weight loss in several disease states, however weight and muscle mass gain was not present or minimal. Until now, limited research has been done examining muscle protein metabolism and the response to EPA and DHA supplementation in patients with COPD. It is the investigator's hypothesis that supplementation of 2g/day EPA+DHA in COPD patients during 4 consecutive weeks will increase the muscle anabolic response to a high quality protein supplement as compared to a placebo, and supplementation of 3.5g/day EPA+DHA will increase the anabolic response even further. In the present study both the acute and chronic effects of EPA+DHA versus a placebo on muscle and whole body protein metabolism will be examined. The principal endpoint will be the extent of stimulation of net fractional muscle protein synthesis as this is the principal mechanism by which the effect of EPA+DHA on muscle anabolism can be measured. The endpoint will be assessed by isotope methodology which is thought to be the reference method.
The purpose of this study is to determine if toddlers and children who were fed breast milk or infant formulas at different levels of protein between 3 and 12 months of age have differences in growth and body composition at 3 and 5 years of age.
Military personnel face many physiological challenges, including sustained physical activity and prolonged periods of negative energy balance. Chronic energy deficiency often results in a loss of skeletal muscle mass and can reduce overall bone health. Recent evidence suggests that dietary interventions that provide protein in excess of the current national dietary recommendation may confer protection against the negative effects of energy deficiency on the musculoskeletal system. The primary objective of this randomized, controlled study is to assess the effects dietary protein intake spanning the current acceptable macronutrient distribution range on musculoskeletal health following prolonged energy deficiency. Findings from this investigation will improve current understanding of dietary conditions necessary to reduce the damaging effects of caloric deficiency on musculoskeletal health in warfighters. Furthermore, given the rise in obesity in military populations, findings may aid in the development of nutritional weight management strategies that promote healthy weight loss without compromising musculoskeletal health.
Weight loss commonly occurs in patients with chronic obstructive pulmonary disease (COPD), negatively influencing their quality of life, treatment response and survival. Loss of muscle protein is generally a central component of weight loss in COPD patients. Attempts to reverse muscle loss in COPD by supplying large amounts of protein or calories to these patients have been unsuccessful. Gains in muscle mass are difficult to achieve in COPD unless specific metabolic abnormalities are targeted. The investigators recently observed that alterations in protein metabolism are present in normal weight COPD patients. Elevated levels of protein synthesis and breakdown rates were found in this COPD group indicating that alterations are already present before muscle wasting occurs. Furthermore, reduced plasma essential amino acid (EAA) levels were observed in COPD patients. These reduced EAA plasma levels were significantly related with the presence of muscle wasting in COPD. Until now, limited research has been done examining protein metabolism and the response to feeding in patients with COPD. Previous studies support the concept of essential amino acids (EAA) as an anabolic stimulus in the young and elderly and in insulin resistant states. Until yet no information is present on the anabolic effects of EAA in elderly COPD patients. It is therefore our hypothesis that a high-leucine essential amino acids mixture specifically designed to stimulate protein anabolism will target the metabolic alterations of COPD patients. In the present study, the acute effects of an EAA nutritional supplement on whole body, muscle and liver protein metabolism will be examined in COPD patients and compared to a supplement consisting of a balanced mixture of total amino acids. The principal endpoints will be the extent of stimulation of whole body protein synthesis as this is the principal mechanism by which either amino acid or protein intake causes muscle anabolism, and the reduction in endogenous protein breakdown. Both endpoints will be assessed by isotope methodology which is thought to be the reference method.
Weight loss commonly occurs in lung cancer patients, negatively influencing their quality of life, treatment response and survival. Gains in lean body mass are difficult to achieve in cancer unless specific metabolic abnormalities are targeted. It is our hypothesis that a nutritional supplement containing a high amount of essential amino acids will target the metabolic alterations of cancer patients. Preliminary research performed in our laboratory in elderly supports this hypothesis. We hypothesize that intake of an essential amino acid nutritional supplement will positively influence protein synthesis rate in advanced non-small cell lung cancer (NSCLC) patients. Furthermore, insight in the underlying mechanism of the higher anabolic response of the essential amino acid supplement will be examined. This information will potentially enable us to formulate a supplement that is more effective than normal food intake, and that will reduce the need for muscle protein breakdown.
Malnutrition, including muscle wasting commonly occurs in children with cystic fibrosis (CF), negatively influencing their quality of life and survival. At the time of a diagnosis of CF, severe protein deficits can already be present. It is important to get CF children fed adequately to prevent that their condition becomes worse or that recovery takes longer. Oral supplementation trials showed that gains in lean body mass are difficult to achieve in CF unless specific metabolic abnormalities are targeted. However, the specific needs for certain food components are not clear yet in children that are ill. Therefore, more information is necessary on the need for protein and certain amino acids in children with CF. Previous studies support the concept of essential amino acids (EAA) as an anabolic stimulus in the young and elderly and in insulin resistant states. Until yet no information is present on the anabolic effects of EAA in CF. It is therefore our hypothesis that a high-leucine essential amino acids mixture specifically designed to stimulate protein anabolism will target the metabolic alterations of pediatric subjects with CF. In the present proposal, the acute metabolic effects of this high leucine essential amino acids mixture will be examined in pediatric subjects with CF and compared to that of a regular balanced total mixture of essential and non-essential amino acids. The principal endpoints will be the extent of stimulation of whole body protein synthesis as this is the principal mechanism by which either amino acid or protein intake causes muscle anabolism, and the reduction in endogenous protein breakdown. Both endpoints will be assessed by isotope methodology which is thought to be the reference method.
The aim of this study is the first aim of a NIH project that consists of 3 aims. The first aim examines the acute effects of two high-quality milk proteins (casein vs. whey) on whole-body and muscle protein metabolism in COPD patients with severe loss of muscle mass and the effects of adding leucine. The principal endpoints will be the extent of stimulation of net whole body protein synthesis as this is the principal mechanism by which either amino acid or protein intake causes muscle anabolism. After determining the optimal nutritional formulation based on the first aim we will continue to work on the second and third aim where fish oil supplementation will be part of the nutritional intervention as well.
Estrogen is necessary for feminization during puberty and to decrease bone resorption, the latter critical for the achievement of peak bone mass and normal bone health in the female. The practicing pediatric endocrinologist often faces the dilemma of how to best feminize girls with hypogonadism (lack of estrogen), manifested as delayed or arrested puberty, due to disorders of the brain or the ovaries. We propose a series of studies to address which type, dose, and route of delivery of estrogen are suitable choices in feminizing and sustaining estrogen concentrations in adolescent girls with Turner syndrome. To accomplish this we will study girls/young woman between the ages of 13 to 20 with Turner Syndrome in 2 protocols. In Protocol # 1 we will study 24 girls with TS, they will receive 3 different estrogen preparations, either by mouth or via a patch for a total of 6 weeks. They will come to the clinical research center for blood draws after 2 wks of taking the estrogen. With this study, we hope to learn how the body responds to estrogen differently, depending on the form estrogen is given and how high, estrogen levels gets in the blood in these girls with Turner Syndrome. We will be comparing these patients estrogen levels to girls that menstruate normally and do not have Turner Syndrome. In Protocol #2, 40 patients with TS will be recruited; these patients will take estrogen for 1 year, either by mouth or via a patch. Patients will come to the lab for blood drawn in 7 occasions and we will measure estrogen levels as well as other hormones and lipid levels. We will also perform a Dual-energy X-ray absorptiometry (DXA) study (like an X ray) to assess body composition and bone mineralization. We will adjust doses based on the estrogen levels we find. With this study we hope to learn how estrogen affects body composition, i.e., the amount of fat vs. muscle, and how different forms of estrogen affect blood cholesterol and other hormones. This study will allow us to understand better how to best replace young woman with Turner Syndrome with estrogen.