Module 6: Diabetes and Obesity

Question 1

What is Type 1 diabetes

symptom, causes, diagnosis

Answer 1

• 10% of diabetic cases
• complete lack of insulin (body does not produce it)
• Autoimmune disorder: immune system attacks and destroys pancreatic ß cells
• Needs: environmental stimulus (infection) & genetic determinant (that allows ß cells to be targeted)
• Symptoms appear when 80-90% of ß cells are destroyed (during childhood/puberty)
  3 main symptoms:
• polyuria (frequent urination), polydipsia (excessive thirst), polyphagia (excessive hunger)
• fatigue, weight loss, weakness
  Diagnosis
• fasting blood glucose, FBG ≥ 126 mg/dl (normal is 70-99)

Question 2

Describe the metabolic effect of type 1 diabetes: Hyperglycemia and ketoacidosis

Answer 2

1. Hyperglycemia and ketoacidosis
   - liver increases glucose production, while muscle and adipose take up less glucose
   - Liver increases gluconeogenesis regardless if there’s glucose present
   - increased mobilization of FAs from adipose, increased oxidation of FAs in liver & increased ketone body synthesis

Question 3

Describe the metabolic effect of type 1 diabetes: hypertriacylglyceridemia

Answer 3

• high lvls of triacylglycerides in blood
• liver cant dispose all FAs so they’re packaged as VLDL
• chylomicrons and VLDL in plasma increase due to decrease in lipoprotein lipase activity

Question 4

What is the treatment of type 1 diabetes?

Answer 4

• patients rely on exogenous insulin (injections)
  Standard insulin treatment: 1-2 injections/ day
  Intensive insulin treatment: 1+ daily injections
• frequent monitoring of blood glucose
• decrease complications 60% but more difficult to monitor

Question 5

How can hypoglycemia occur in type 1 diabetes?

Answer 5

When too much insulin is administired during insulin therapy

Question 6

What is type 2 diabetes?

symptoms, causes, diagnosis

Answer 6

• most common (90% of cases)
• strong genetic contribution
• results from:
  1. insulin resistance: insulin is present but cells (in liver, adipose, and muscles) aren’t responding to its presence (caused by obesity)
  2. Non-functional ß cells: inability to keep up with demand to produce insulin; if normal, ß-cells can increase amount of insulin
  Diagnosis & symptoms
• develops gradually some experience polyuria, polydipsia, polyphagia
• diagnosis based on hyperglycemia: blood glucose conc > 126 mg/dl

Question 7

What is insulin resistance? What are the causes?

Answer 7

• liver, adipose, and muscle cells can’t respond to normal insulin levels
• signalling cascade not happening in response to insulin lvls
• results uncontrolled production of glucose in liver and decreased glucose uptake by muscles and adipods
• causes obesity
• insulin resistance increases with weight gain
• Changes in adipose secretions in obesity leads to insulin resistance

Question 8

How is hyperglycemia associated with type 2 diabetes?

metabolic changes in type 2 causes….

Answer 8

increased production of liver glucose + decreased tissue usage of glucose
- ketosis is minimal: presence of insulin lowers ketogenesis

Question 9

How is hypertriacylglycerolemia associated with type 2 diabetes?

metabolic changes in type 2 causes….

Answer 9

low lipoprotein breakdown in adipose due to low levels of lipoprotein lipase leads to elevated TAG in blood

Question 10

Treatment for type 2 diabetes

Answer 10

modification of diet, weight loss, exercise, hypoglycemic drugs

Question 11

What is the fed state?

Answer 11

• 2-4 hours after a meal
• anabolic period
• insulin predominant hormone

Question 12

What is the fasted state?

Answer 12

• 4 hours after food has been injested
• focus is maintaining blood glucose for brain
• catabolic period
• glucagon is predominant hormone

Question 13

What is obesity? What is it caused by?

Answer 13

A complex disorder of body weight regulatory systems
(excess body fat)
- increase in cell size (hypertrophy) and cell number (hyperplasia)

Question 14

What are the 2 types of body shapes/fat depots? Describe both.

Answer 14

1. upper body obesity: apple-shaped
   - fat around central abdomen
   - higher risk of health defects
   - associated with high BP, insulin resistance, diabetes, heart disease
2. Lower body: pear-shaped
   - 80-90% fat stores in subcutaneous depots in abdominal region
   - 10-20% stored in visceral depots within abdominal cavity
   - more biochemically active

Question 15

True or False: Subcutaneous adipocytes in lower body are larger, very efficient TAG stores

Answer 15

True

more common in women

Question 16

True or False: Abdominal fat cells have a higher rate of fat turnover and are more responsive to hormones

Answer 16

True

more common in men

Question 17

What signals regulate body weight?

Answer 17

• Incoming (afferent) signals promote response from hypothalamus (efferent signals): influences appetite
• leptin levels communicate with brain about body fat
• Insulin acts on neurons to dampen appetite

Question 18

What role do the signals regulating body weight play in obesity development?

Answer 18

• When leptin levels are increased, this means there’s an increase in fat so, appetite is supressed
• leptin is synthesized in proportion to body fat levels

Question 19

What metabolic changes occur during obesity?

Answer 19

Increased mass of adipocytues results in:
1. metabolic syndrome: abdominal obesity associated with insulin resistance, dyslipidemia, and high BP
- increased risk of type 2 diabetes
2. Dyslipidemia: abnormal accumulation of lipids in the blood
- HDL cholesterol decreases
- TAG and LDL increases

Question 20

What is metabolic syndrome (MetS)?

Answer 20

cluster of conditions that lead to disease state.
- Requires lifestyle changes: weight loss, exercise, medication