Diabetes Learning Objectives (L20)

Question 1

What is the mechanism by which GLUT-4 transporters are expressed on the membrane of muscle cells during exercise?

Answer 1

• GLUT-4 transporters stored in the cells in vesicles
• Transporters need to move/translocate to cell membrane somehow
• In exercise, this is insulin INDEPENDENT, it is mediated via muscle contraction

Question 2

What are 2 reasons why exercise so beneficial for diabetics with respect to blood sugars?

Answer 2

a) Regular exercise improves insulin sensitivity. For individuals with diabetes who require exogenous insulin therapy, exercise helps to optimize insulin sensitivity, reducing the amount of insulin needed to achieve glucose uptake into cells.
b) During exercise, muscle contractions stimulate the translocation of glucose transporter type 4 (GLUT-4) to the cell membrane, facilitating the uptake of glucose into muscle cells.

Question 3

What is contraction-regulated glucose uptake?

Answer 3

Muscle contractions stimulate the translocation of glucose transporter type 4 (GLUT-4) to the cell membrane, facilitating the uptake of glucose into muscle cells

Question 4

What is the difference between Type A- and Type B- T1DM?

Answer 4

Type A: Autoimmune cause
Type B: Idiopathic cause

Question 5

Diabetics have decreased insulin sensitivity. Why does this predispose diabetics to ketoacidosis?

Answer 5

• Without sufficient insulin, cells cannot effectively uptake glucose from the bloodstream, leading to high blood sugar levels (hyperglycemia).
• In response to hyperglycemia and insulin deficiency, the body perceives a state of cellular starvation, similar to fasting.
• The body breaks down other substrates to attempt to derive ATP (since no glucose is detected in the cells). One method is increasing lipolysis, leading to elevated FFA in the blood stream
• The excess free fatty acids are converted into ketone bodies in the liver. This leads to an accumulation of ketones in the bloodstream, resulting in ketoacidosis.

Question 6

What is the mechanism by which diabetics often become thirsty?

Answer 6

• Body fluid can be highly saturated with glucose, more fluid is passed in urine in an attempt to eliminate glucose in the body
• Osmoreceptors detect the change in fluid and trigger thirst

Question 7

What changes in insulin levels are reflected in the progression of T2DM? What causes the changes in these levels?

Answer 7

• T2DM is a disease relating to a high diatery glucose intake. Over time, the body will naturally develop an insulin resistance.
• Initially, the body produces lots of insulin to overcome insulin resistance and the body’s reduced responsiveness to insulin’s actions
• This compensatory response helps to prevent immediate hyperglycemia but can lead to beta-cell exhaustion over time.
• As the disease progresses over time, you would observe a high-, moderate-, then low-levels of insulin.

Question 8

What are the risk factors for T2DM?

Answer 8

– Age
– Obesity (diabesity)
– High energy diet
– Lack of physical activity
– Sedentary behaviour
– More common in non-Caucasians
– High plasma TGs, low HDLs, systemic inflammation (high CRP)

Question 9

What are the macrovascular consequences of T2DM?

Answer 9

– Atherosclerosis
– CAD (leading cause of death in diabetics)
– PVD (increases risk of amputation)

Question 10

What is the leading cause of death in T2DM patients?

Answer 10

CAD

Question 11

What are the microvascular consequences of T2DM?

Answer 11

– Retinopathy (main cause of adult blindness)
– Nephropathy (renal disease)
– Neuropathies:
* Demyelination & degeneration of neurons
* Starts peripherally, progresses centrally

Question 12

Is sitting a risk factor in all diabetics?

Answer 12

No. Studies show it is only a risk factor in:
- Obese adults
- Inactive adults

Question 13

What are the treatments for T2DM? (List the lifestyle and pharmacological treatments)

Answer 13

• Lifestyle changes
  – Diet
  – Physical activity
  – Weight (fat) loss desirable
• Pharmacological
  – Oral hypoglycemic medications
  – Insulin (20-30%)