Obesity and related disorders such as type 2 diabetes are a worldwide diet-related problem. As such new treatment options are constantly being developed. Bacteria living in the gut seem to be a key player in the treatment of obesity and related metabolic diseases by influencing energy balance and the immune system. In terms of newly identified bacteria species, Akkermansia muciniphila (A. muciniphila) has been found to be related to obesity. Several animal studies have shown the beneficial impact of A. muciniphila on the treatment of body weight as well as insulin sensitivity. The growth requirements of live A. muciniphila as well as its oxygen sensitivity rendered this bacterium unsuitable for human investigations or putative therapeutic opportunities. Therefore, pasteurization, a mild heating method, and its impact on diet-induced metabolic disorders in mice were investigated. Unexpectedly, this method of inactivation did not negate the effect of A. muciniphila, but improved its beneficial metabolic effects. Pilot studies have provided further evidence that pasteurization of A. muciniphila is safe for human use and has the potential to beneficially affect the control of body weight and glucose metabolism. In this project, The investigators hypothesize that pasteurized A. muciniphila will be superior to placebo intervention in maintaining body weight after a phase of weight loss (low caloric diet) in adult participants with overweight or obesity.
RATIONALE This study will examine the influence of specific beneficial gut bacteria in relation to weight maintenance. The worldwide prevalence of obesity, obesity-associated insulin resistance, and type 2 Diabetes Mellitus (T2DM) has grown dramatically over the last couple of decades; in every region of the world, obesity prevalence has more than tripled since 1975. Even though obesity treatment strategies, such as lifestyle interventions (focussed on diet and/or physical activity) and bariatric surgery have improved, there is extensive variability in responses. In the short term, reducing body weight is relatively easy, for most people. However, maintaining weight loss in the long term is a challenge. Hence, novel strategies to reduce these pandemics and support weight maintenance are strongly warranted. The gut microbiome has emerged as an important regulator of host energy metabolism, thereby contributing to the etiology of obesity and obesity-related insulin resistance. However, scientific evidence is mainly derived from animal experiments and association studies, and support for causality in humans using mechanistic studies is limited. The influence of a newly identified bacterium, A. muciniphila. has been shown to be associated with a healthy intestine, and its abundance is inversely correlated to several disease states amongst others obesity and insulin resistance. However, the growth requirements of live A. muciniphila as well as its oxygen sensitivity(12) rendered this bacterium unsuitable for human investigations or putative therapeutic opportunities. Therefore, pasteurization, a mild heat inactivation method (30 min at 70 degrees Celsius), and its impact on diet-induced metabolic disorders in mice were investigated. Unexpectedly, this method of inactivation did not abolish the effect of A. muciniphila but even exacerbated its beneficial impacts. In mice, daily administration of pasteurized A. muciniphila alleviates diet-induced obesity. Moreover, a randomized, double-blind, placebo-controlled proof-of-concept study in overweight/obese insulin-resistant adults showed that the daily supplementation with pasteurized A. muciniphila for 12 weeks improved several metabolic parameters such as insulin sensitivity, insulinemia, plasma total cholesterol, as well as relevant blood markers for liver dysfunction and inflammation independently from any caloric restriction or modification of the physical activity. The investigators hypothesize that pasteurized A. muciniphila will be superior to placebo intervention in maintaining body weight after a low caloric diet in participants with overweight or obesity. OBJECTIVES 1. To investigate the effects of pasteurized A. muciniphila on the maintenance of body weight after a phase of weight loss. 2. To investigate the effects of pasteurized A. muciniphila on body composition and body fat distribution, glucose homeostasis and insulin sensitivity, and metabolic health. 3. To investigate the effects of pasteurized A. muciniphila on the fecal bacterial composition and functionality, systemic inflammation, and gut barrier function and identify relevant biomarkers. STUDY DESIGN The proposed study is a 32-week double-blind placebo-controlled randomized trial in 108 healthy overweight/ obese (BMI ≥ 28 kg/m2 \< 40 kg/m2) Dutch adults, aged 20-70 years. All participants will follow a commercially-prepared low-calorie diet, with 15-20 energy % from fat, 35-40 energy % from protein, and 45-50 energy % from carbohydrates for a period of 8 weeks, to lose 8% of their body weight. In addition to these prepared meals, participants will be allowed limited consumption of specific low-calorie vegetables. Participants will be randomized to either the placebo or the intervention group following the weight-loss period. The weight loss phase will be followed by a 24-week supplementation placebo or active ingredient and a weight maintenance period. Prior to, as well as during both phases of the study participants will receive regular weigh-ins (weeks 0, 1, 4, 8, 16, 24, and 32) and counseling from a registered dietician. In addition to measuring changes in weight and physical measurements, participants will fill in questionnaires, and provide blood and fecal samples at weeks 0, 8, and 32. QUALITY ASSURANCE Study activities will be carried out by qualified trained personnel, following standard operating procedures (SOP's). All research activities, including data entry and SOP compliance, will be monitored by an independent monitoring board, Clinical trial center Maastricht (CTCM). Data will be analyzed and handled according to the data management and statistical analysis plan.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
90
During the weight management period (weeks 8 to 32), the pasteurized A. muciniphila product will be orally consumed in water at least 15 min before breakfast for a period of 6 months (24 weeks) capsules. It appears as a white homogenous powder. .
During the weight management period (weeks 8 to 32), the placebo product will be orally consumed in water at least 15 min before breakfast for a period of 6 months (24 weeks). It appears as a white homogenous powder.
Department of Human Biology, Maastricht University Medical Centre
Maastricht, Limburg, Netherlands
Body weight
Changes in body weight following the initial weight loss period will be monitored over the weight maintenance period.
Time frame: 6 months
Body composition
Changes in body composition following the initial weight-loss period as assessed by dual-energy X-ray absorptiometry (DEXA), and body mass index (BMI).
Time frame: 8 months
Body fat distribution
Changes in body fat distribution following the initial weight-loss period as assessed by the waist to hip ratio, as measured by waist and hip circumferences.
Time frame: 8 months
Glucose metabolism
Changes in glucose metabolism will be assessed by fasting glucose and hemoglobin A1C (HBA1c).
Time frame: 8 months
Insulin sensitivity
Changes in glucose and insulin responses to a 7 point oral glucose tolerance test.
Time frame: 8 months
Lipid profile
Changes in total cholesterol, triglycerides (TG), low-density lipoprotein) (LDL), high-density lipoprotein (HDL), and non - esterified fatty acids (NEFA) will be considered together to give an indication of the overall lipid profile as a result of the LCD and active intervention.
Time frame: 8 months
Adipose tissue activity
Changes in adipose tissue gene/protein expression will be assessed.
Time frame: 8 months
Gut barrier function
Gut barrier function will be assessed using serum/fecal zonulin, fecal calprotectin, serum LBP, and serum LPS. These measurements will be considered together to give an indication as to the function of the gut barrier, i.e. if it is normal, disrupted, or has improved as a result of the LCD and or active intervention.
Time frame: 8 months
Psychological well-being - mental health
Well-being, as it relates to feelings of depression and anxiety, will be measured using the Hospital Anxiety and Depression Scale (HADS) questionnaire.
Time frame: 8 months
Psychological well-being - sleep quality
Well-being, as it relates to sleep and sleep quality, will be assessed using the Pittsburgh Sleep Quality Index (PSQI)
Time frame: 8 months
Psychological well-being - stress
Well-being, as it relates to perceived stress, will be assessed using the 10-item Perceived Stress Scale (PSS).
Time frame: 8 months
Psychological well-being - General
general well-being will be assessed using the 36-Item Short-Form Health Survey (Rand - 36/ SF-36) .
Time frame: 8 months
Gastrointestinal symptoms - bowel movements
Gastrointestinal symptoms related to bowel movement frequency and consistency will be measured using the Bristol Stool Charts (BSC).
Time frame: 8 months
Gastrointestinal symptoms
Gastrointestinal symptoms will be measured using the Gastrointestinal Symptom Rating Scale questionnaire.
Time frame: 8 months
Heart rate
Changes in heart rate will be monitored over time
Time frame: 8 months
Blood pressure
Changes in blood pressure (systolic blood pressure (SBP), diastolic blood pressure (DBP)) will be measured over time.
Time frame: 8 months
Renal function
Changes in renal function, before during, and after the LCD and intervention will be monitored with blood creatinine, sodium, potassium, and chloride concentrations. These measurements will be considered together to determine if renal function is stable, has deteriorated, or improved.
Time frame: 8 months
Liver function
Changes in liver function will be monitored before during and after the LCD and active intervention using blood alanine aminotransferase (ALAT), aspartate transaminase (ASAT), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), bilirubin, and, albumin. These measurements will be considered together to determine if liver function is stable, has deteriorated, or improved.
Time frame: 8 months
Inflammation
Inflammation will be monitored using C- reactive protein (CRP), lipopolysaccharide-binding protein (LBP), lipopolysaccharide (LPS), and serum zonulin.
Time frame: 8 months
Microbiota
Fecal samples to be used for analyzing microbiota composition will be collected and compared between groups.
Time frame: 8 months
Short chain fatty acid production
Circulating fatty acids will be measured as a measure of function of the microbiota
Time frame: 8 months
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