The Potential of Carnosine Supplementation in Optimising Cardiometabolic Health

Study Overview
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Brief Summary
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The investigators hypothesise that carnosine supplementation will improve: glycaemic control cardiovascular risk factors cognitive outcomes in patients with prediabetes and type 2 diabetes, and this will be modulated by reduction in chronic low grade inflammation, oxidative stress and circulating advanced glycation end products levels. 3. Aims To determine the potential of carnosine supplementation for 14 weeks to improve glycaemic control in type 2 diabetes, reduce risk factors for cardiovascular disease and improve cognitive function as well as identify metabolic pathways involved, specifically by: Improving glycaemic control (HBA1c, fasting and 2 hour glucose and glucose area under the curve after oral glucose tolerance test) Reducing cardiovascular risk factors (lipids; arterial (aortic) stiffness; central blood pressure (cBP); endothelial function). Improve cognitive function (global cognitive score formed by a composite of 4 cognitive tests) Decrease the chronic low grade inflammation, oxidative stress, advanced glycation end products, and advanced lipoxidation end products, and increase detoxification of reactive carbonyl species (RCSs).

Detailed Description
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Type 2 diabetes is a major public health problem worldwide. Obesity itself markedly increases the risk of type 2 diabetes (DM2), which now affects every second obese person. With 60% of adult Australians overweight or obese and 25% of Australians aged over 25 years having prediabetes or diabetes, the quality-of-life and cost impact is inescapable. In Australia, direct healthcare costs for DM2 are currently estimated as $1.1 billion annually, with the prospect of doubling by 2025. Obesity and DM2 dramatically increase the risk of cardiovascular disease (CVD) with  80% of individuals with both obesity and DM2 develop CVD. The annual healthcare costs for CVD in Australia now amount to $7.7 billion; and the total aggregated costs, including loss of income, are much higher again. Treating DM2 and CVD is expensive and often unsatisfactory. Weight loss and exercise are the mainstay of prevention and therapy but they are difficult and costly to achieve on a large scale; hence the DM2 epidemic continues unabated. Therefore, interventions at low cost and easy to implement at the population level is urgently required. Neurodegenerative diseases often occurs in people with DM2, and DM2 is in turn associated with increased risk of cognitive decline. Neurodegenerative diseases such as Alzheimer's disease are also associated with metabolic impairment. They share many common pathogenic features with DM2 such as insulin resistance, chronic low-grade inflammation, vascular disease, oxidative stress and accumulation of advanced glycation endproducts (AGEs). Progression of these diseases over years-decades is also worsened by a sedentary life-style. Therefore not surprisingly, regular physical activity is beneficial in those patients, likely due to improvement of neurological, motor and cardiometabolic profile. However, it is difficult and costly to achieve on a large scale, and thus, safe and low-cost strategies are needed. Type 2 diabetes is associated with increased amounts of ectopic fat depots in muscle including intramyocellular lipids (IMCL), and adipocytes located between muscle groups (inter-muscular) and also between muscle fascicles (intramuscular). Both IMCL and intra- and inter-muscular adipose tissue (IMAT) may deleteriously effect muscle metabolism and insulin sensitivity through increased local secretion of pro-inflammatory adipokines, and inter-muscular fat may additionally impair insulin action through reductions in blood flow to muscle. Could carnosine be that strategy? Strong molecular and animal data (>2000 papers) suggests that it has great potential, with all the relevant properties. Carnosine, is present in several tissues including muscle and brain, easily crosses the blood-brain barrier, and extensive animal data show that carnosine has chelating properties and modulates glucose metabolism, advanced glycation, pro-inflammatory and pro-oxidative states, as well as motor functions and neurotransmission. A promising further use may derive from its effect on cardiometabolic health and neuroprotection. Current research, confined to animal studies, supports carnosine supple¬ment¬ation for preventing and treating obesity, DM2, CVD, and neurodegenerative diseases - by virtue of its anti-inflammatory, antioxidative, anti-glycating and chelating effects. Our team's novel pilot studies provide the first human cross-sectional and interventional metabolic data, and demonstrate relationships among carnosine, obesity, insulin resistance, and dyslipidaemia. Previous clinical trials also showed that supplementation of carnosine for 2-3 months improved cognitive performance in healthy individuals and patients with neurodegenerative diseases. However, none of them showed its effect in patient with type 2 diabetes and explored the effects of change in cardiometabolic outcomes on cognitive function. Apart from its excellent side-effect profile, carnosine is cheap and safe (it is an over-the-counter dietary supplement), making it prima facie ideal for widespread, low cost use. Robust human research is now urgently needed to test the therapeutic potential of carnosine in improving cardiometabolic profile and cognitive function, and study the mechanisms involved.

Official Title
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The Potential of Carnosine Supplementation in Optimising Cardiometabolic Health in Patients With Prediabetes and Type 2 Diabetes: a Randomsied, Double-blinded, Placebo-controlled Trial

Conditions
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Poor Glycemic Control, Cardiovascular Risk Factors, Cognitive Function 1, Social

Intervention / Treatment
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* Dietary Supplement: carnosine
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age >=18 or <=70 years Weight change < 5 kg in last 6 months HbA1c level <= 8% Patients with prediabetes (Impaired glucose tolerance and impaired fasting glycaemia) or type 2 diabetes (diet controlled or on oral therapy) Patients will have to be on oral therapy for diabetes (without changes in treatment) at least for 3 months. Patients will be advised not to change their pre-existing therapy for diabetes and cardiovascular risk factors for the duration of the study if HbA1c is not above 8% No recent blood transfusion (3 months) No current intake of anti-inflammatory medications and supplements No significant kidney, cardiovascular, haematological, respiratory, gastrointestinal, or central nervous system disease, as well as no psychiatric disorders, no active cancer within the last five years; no presence of acute inflammation (by history, physical or laboratory examination) Pregnant or lactating Exclusion Criteria: Age <18 or > 70 years HbA1c level of >= 8% Weight change > 5 kg in last 6 months Morbid obesity (body mass index >40 kg/m2) Current smoking habit and high alcohol use Patients on insulin Taking anti-inflammatory medications or supplements Recent blood transfusion history Kidney (estimated glomerular filtration rate < 30 ml/min), cardiovascular, haematological, respiratory, gastrointestinal, or central nervous system disease, as well as psychiatric disorder, active cancer within the last five years; presence of acute inflammation (by history, physical or laboratory examination) Pregnancy or lactation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Intervention<br>Each participant will be given a daily oral dose 2 g of carnosine (4 tablets of 500mg each) for 14 weeks | Dietary Supplement: carnosine<br>* Each participant will be given a daily oral dose 2 g of carnosine (4 tablets of 500mg each) for 14 weeks<br>* Other names: Pure Carnosine;|
| Placebo Comparator: Control<br>Each participant will be given a daily oral dose 2 g of placebo (4 tablets of 500mg each) for 14 weeks | Drug: Placebo<br>* Each participant will be given a daily oral dose 2 g of placebo (4 tablets of 500mg each) for 14 weeks<br>* Other names: Methylcellulose;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Oral Glucose Tolerance Test | After a 10-12 h overnight fast, participants will ingest 75g of glucose over 2 mins. Blood samples will be drawn at 0, 30, 60, 90 and 120 min for plasma glucose and insulin concentrations. We will evaluate the area under the curve. | baseline and 14 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in HbA1c | Blood samples will be measured using High Performance Liquid Chromatography. | baseline and 14 weeks | 
| Change in lipid profile | Blood samples will be analysed using High Performance Liquid Chromatography | baseline and 14 weeks | 
| Change in systolic and diastolic blood pressure | Resting systolic and diastolic blood pressure and pulse rate will be measured using an automated oscillometric measurement system (Dinamap, USA) after a 30 minute rest. | baseline and 14 weeks | 
| Change in arterial stiffness and central blood pressure | Aortic (carotid-femoral) pulse wave velocity (aPWV) will be measured using the non-invasive Complior device (Alam Medical, French). | baseline and 14 weeks | 
| Change in markers of endothelial dysfunction | This is done using non-invasive peripheral arterial tomography (PAT; endothelium-dependent digital pulse amplitude testing (EndoPAT), Itamar Medical Ltd, Israel), which records continuous plethysmographic signals of the finger arterial pulse wave. Finger plethysmographic probes are placed on each index finger; and after a 5 min equilibration period, a blood pressure cuff on the non-dominant arm is inflated to 60 mmHg above systolic for 5 min and then deflated to induce reactive hyperaemia. Measurements of post-occlusion changes (reactive hyperaemia PAT: RH-PAT) are continued for 10 min. Results are normalised to the non-occluded arm, compensating for potential systemic changes (RH-PAT ratio). | baseline and 14 weeks | 
| Change in heart rate variability | The Zephyr Biomodule BH3 (Black Sensor, produced by Zephyr Technology) will be used to measure heart rate and heart rate variability for three consecutive days. | baseline and 14 weeks | 
| Change in interleukins | Interleukins will be measured by quantitative sandwich enzyme immunoassays (R & D Systems Inc, USA). | baseline and 14 weeks | 
| Change in tumour necrosis factor α | Tumour necrosis factor α (TNFα) will be measured by quantitative sandwich enzyme immunoassays (R & D Systems Inc, USA). | baseline and 14 weeks | 
| Change in macrophage migration inhibitory factor | Macrophage migration inhibitory factor will be measured by quantitative sandwich enzyme immunoassays (R & D Systems Inc, USA). | baseline and 14 weeks | 
| Change in plasma C- reactive protein | Plasma C- reactive protein (hsCRP) will be measured using high sensitivity assay (BN-II nephelometer; Dade Behring Diagnostics, NSW). | baseline and 14 weeks | 
| Change in plasma and urinary advanced glycation end products | Measured by liquid chromatography-tandem mass spectrometry and ELISA tests. Circulating receptor for AGEs will be measured by ELISA. Protein modifications and the effect of carnosine supplementation will be determined by proteomic approaches. | baseline and 14 weeks | 
| Change in plasma and urinary advanced lipoxidation end products | This will be determined by measuring the advanced oxidation protein products and by measuring the cysteinate form of albumin by mass spectrometry. Mercapturic acid adducts with the main reactive carbonyls species will also be quantitatively determined by liquid chromatography electrospray ionization mass spectrometry/mass spectrometry analysis (LC-MS/MS). | baseline and 14 weeks | 
| Change in general cognitive function | Participants' cognitive function will be assessed using Cambridge Neuropsychological Test Automated Battery (CANTAB) battery for Prodromal Alzheimer's disease, Victoria Stroop test, Trail Making Test and Digit Symbol Substitution Test. | baseline and 14 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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carnosine, type 2 diabetes, cardiovascular factors