Pathology of Diabetes Mellitis and its Complications Flashcards
what is the aetiology of type 1 diabetes?
not entirely known
genes found so far- molecules that help T cells recognise self from non-self= human leukocyte antigen molecules
autoimmune attack on islet cells- lymphocyte infiltration of islets- destruction of B cells
what happens in type 1 diabetes mellitus?
Cannot distinguish own cells from other cells –> autoimmune attack on pancreatic B cells
what is the result of destruction of islets?
decreased insulin
what are the environmental triggers/aetiology of type 1 diabetes
? Chemicals
? Bacteria in gut altered in infancy
? Viral infection - ? Molecules on viral surface mimic molecules on outside of B cells
destruction of B cells causes (insulin) (glucose)
decrease insulin and increase in glucose
aetiology of type 2 diabetes mellitus?
Combination of:
1) reduced tissue sensitivity to insulin (insulin resistance) and
2) inability to secrete very high levels of insulin
a failure of the B cells to meet an increased demand for insulin in the body
what are the environmental triggers of type 2 diabetes?
Expanded upper body visceral fat mass - due to increased intake of food and lack of exercise
what does expanded upper body visceral fat mass result in?
increased free fatty acids in blood
decreased insulin receptor sensitivity to insulin
which then causes decreased removal of glucose from blood
which then leads to raised glucose, and insulin levels then have to markedly increase to make glucose go back to normal levels
what does central adiposity ultimately lead to?
hyperinsulinaemia
what type of genes are involved in type 2 DM?
Implicated genes are for poor B cell ‘high end’ insulin secretion- so if you have only a few genes abnormal you will be able to secrete lots of insulin
therefore you can have central adiposity but if you have many genes promoting high end insulin secretion your glucose levels can still be okay
:)
if you have central adiposity and numeroous genes defective for high end insulin secretion what does this do?
not enough insulin to decrease glucose therefore glucose increases and results in type 2 diabetes
what are the long term complicaations of DM?
Annual mortality is 5.4% - double the rate of non-diabetics
Life expectancy is decreased by 5-10 years
Myocardial infarction is the commonest cause of death
dammage to vessels- most common
how is atherosclerosis accelerated?
Glucoses attach to low density lipoprotein
Glucose molecules stop low density lipoprotein from binding its receptor (on liver cells) tightly
Low density lipoprotein is not removed by liver cells –> lipoprotein and lipid stay in blood –> Hyperlipidaemia
true or false normal collagen binds to albumin
false normal collagen does not bind to albumin
