L5: Diabetes and physical activity Flashcards
What is diabetes?
Diabetes is a chronic metabolic disease which is characterised by excessive blood glucose concentrations, defective insulin production and utilisation and defective lipid metabolism.
What is the classification of diabetes in terms of fasting glucose concentration?
> 7mmol/L
What is the biomarker that is used to assess diabetes? and why is it useful
Hba1c (Glycated haemoglobin) and indirectly measures glucose concentrations over 3 months.
What are the two main reasons for glucose concentrations to be high in diabetes?
- Insulin resistance reduces cell glucose uptake
2. Over production of glucose from the liver
What percentage of HBA1C is classified as diabetes mellitus?
6.5% (48mmol/mol)
What study identified the increase mortality seen in diabetic patients and the association between HB1AC and mortality?
Tancredi et al, 2015
What conditions can diabetes cause and why?
Diabetes causes damage to micro and macrovasculature due to the high concentrations of circulating glucose.
- Diabetic retinopathy
- Diabetic Neuropathy
- Diabetic nephropathy
- Cardiovascular disease (80% mortality)
- Stroke
What are the pathophysiological effects diabetes have on intestines, brain, pancreas and kidneys?
- Incretin effect reduced.
Incretin effect refers to the consumption of glucose increasing insulin response due to GLP-1 and GIP hormones that stimulate insulin release. in diabetes both hormones are lower. - Neuro dysfunction
Ectopic fat and inflammatory responses also occur in the brain which leads to insulin resistance. Insulin also functions as a hormone suppressor and thus poor satiety and increased appetite occurs favouring a positive energy balance.
3.Glucagon secretion increase
Alpha cells of pancreases secrete glucagon a hormone responsible for increasing glucose production from the liver during fasting. Diabetes increases glucagon production.
- Glucose reabsorption threshold
Threshold of glucose secretion via ruin increases in diabetes, thus allowing increased absorption before glucose levels are reduced. This means elevated glucose levels occur.
What drugs target glucose secretion threshold of the kidneys
SGLT-2 inhibitors
Name a study which identified the effectiveness of low caloric diets for diabetes remission.
Lean et al, 2018 - 850 kcal liquid diet for 12 - 20 weeks found that diabetes remission increased in response to wait loss, with 86% remission in those who lost 15kg or more.
why does low caloric dieting only work as a treatment for diabetes remission before 6 years of diagnosis?
After 6 years pancreatic beta cells are completely destroyed, preventing reversal of diabetes.
Why might lifestyle factors have a larger effect at preventing diabetes in elderly individuals?
Elderly are generally more inactive and so the same relative change in physical activity may actually have a stronger effect.
Why might aerobic exercise be more effective at regulating diabetes mellitus than resistance?
The metabolic pathways of aerobic exercise involves the utilisation and transport of substrates such as NEFA and over time a reduction in adipocyte size. This consequently reduces both ectopic fat formation around organs leading to dysfunction but also reduced NEFA and pro-inflammatory adipocytes.
Utilisation of carbohydrates also reduces blood glucose concentrations whilst the exercise itself promotes GLUT-4 translocation to the cell membrane improving insulin sensitivity.
How does exercise increase GLUT-4 translocation?
Exercise changes cellular energy levels increasing AMP to ATP ratio along with release of CA2+ and ROS production. These trigger pathways including AMPK which ultimately trigger translocation of GLUT-4 receptors.
