Diabetes Intro Flashcards
Define Diabetes mellitus
A metabolic disorder characterized by elevated blood glucose concentrations and disturbances of carbohydrates, lipids and protein due to defective insulin secretion and/or action.
What are different types of diabetes?
- Type 1 DM
- Type 2 DM
- Gestational diabetes
- Other types
- Pre-diabetes
What are the major differences between T1DM and T2DM?
Type 1 DM
- Insulin-dependent (IDDM)
- Juvenile or growth onset
- Ketosis prone
Type 2 DM
- Non-insulin dependent (mostly)
- Maturity onset (mostly)
- Not prone to ketosis
What is T1DM?
Autoimmune or idiopathic destruction of pancreatic ß-cells
→ absolute deficiency in insulin production
What is T2DM?
- Cells do not respond normally to insulin (resistance)
- Cells do not take up and utilize glucose efficiently →
hyperglycemia - Pancreas may compensate or not with insulin production → hyperinsulinemia or normal levels
What is the prevalence of diabetes in Canada?
6.7% (2.0 million) of Canadians >12 yrs reported diagnosed diabetes (type 1, 2 and GDM)
How did the prevalence of diabetes changed in Canada from 2011 to 2013?
Increase from 2011 (but not from 2013)
- 7.5% in males
- 5.8% in females
Which provinces of Canada have the highest and the lowest amount of people with diabetes?
NL, NS and ON had the highest prevalence, while NU, AB and QC had the lowest.
What is the pattern of obesity and diabetes in the U.S?
diabetes follows the prevalence of obesity
increasing since 1994
Which part of the world has the highest prevalence of diabetes in the world?
western pacific - Australia
What is the prevalence of diabetes in the world?
387 Million
46.3% undiagnosed
What is the expected number of increase in people with diabetes by 2035?
+ 205 million people
so 592 million people will be living with diabetes (53% increase)
What are the causes of T1DM?
environmental causes: virus, toxins and genetic predisposition lead to Islet cell auto- antibodies (ICA) and β cell Injury. Therefore, decrease in insulin production.
What are the symptoms/initial observations of T1DM?
- Increased thirst (polydipsia)
- Increased urination (polyuria)
- Increased hunger (polyphagia)
- Weight loss (T1DM) or obesity (T2DM)
What are the symptoms/lab tests of T1DM?
- Glycosuria
- Hyperglycemia
- Abnormal glucose tolerance (GTT)
What are the functions of insulin? (6)
- ↑ glucose uptake and storage
- ↓ glycogenolysis and gluconeogenesis = ↓endogenous glucose production
- ↑lipogenesis
- ↓ lipolysis
- ↑ protein synthesis
- ↓ proteolysis
What are the causes of T2DM?
- Excessive food intake + lack of exercise + genetic predisposition –> obesity
- obesity –> inflammation + insulin resistance
- insulin resistance –> hyperglycemia + Lipotoxicity + ß cell decompensation
What is insulin resistance?
Defined as a lesser sensitivity to insulin’s action in suppressing hepatic glucose production and stimulating glucose uptake
Mostly due to defective insulin signalling within cells
What are the normal steps of insulin-induced glucose uptake?
- In response to rising blood glucose, the pancreas releases more insulin into the blood
- Insulin bind to a membrane-bound receptor
- The binding of insulin to its receptor signals glucose transporters to move from the cytoplasm to the cell membrane
- Glucose transporters enable glucose to move from the extracellular space into the cytoplasm
What are the two types of insulin resistance in terms cellular mechanisms?
Receptor defects: decreased number and affinity
- Rare cases of genetic mutations of INSR gene
Post-receptor second messenger signalling
- Most cases of IR
What are the two types of regulation by insulin action?
long term regulation
- cell growth and differentiation
short term regulation of actions of insulin between fasted and fed state through P of proteins rapidly
- muscle: increased glucose transport and glycogen synthesis
- liver: increased glycogen synthesis, lipogenesis and decreased gluconeogenesis
- adipose: increased glucose transport, lipogenesis and decreased lipolysis
What are the effects of insulin resistance on blood, muscle, liver and adipose tissue?
liver: increased gluconeogenesis
muscle: decreased glucose uptake, glut 4 expression translocation, glucose oxidation, glycogenesis
adipose: increased lipolysis
blood: increased blood glucose and non essential fatty acids (NEFA)
List some of the risk factors for T2DM
o Age
o Obesity
o Sedentary lifestyle
o Ethnicity (e.g. Aboriginal, African, South Asian, Hispanic)
o Prediabetes: impaired fasting glucose or impaired glucose tolerance
o Family history
o History of GDM
o Child of a woman with poorly controlled diabetes during pregnancy
o Low birth weight (<2.5 kg) and high birth weight (>4.0 kg) o Polycystic ovary syndrome (PCOS)
** NOTE: sex is not included
What are other related conditions to insulin resistance?
¢ Obstructive sleep apnea ¢ Infection ¢ Steroid-induced ¢ Cushing’s syndrome ¢ Hemochromatosis ¢ Lipodystrophic diabetes ¢ Acanthosis nigricans ¢ Werner’s syndrome (adult form of progeria) ¢ Idiopathic
Explain the metabolic staging of type 2 diabetes
obesity –> insulin resistance –> impaired glucose tolerance + impaired fasting glucose –> hyperinsulinemia + hyperglycemia –> beta-cell defect –> decreased insulin secretion –> early diabetes –> beta-cell failure –> late diabetes
Can early diabetes be reversed?
Yes! Reversible by weight loss, exercise, medication