Pathology of Diabetes Mellitus and Its Complications Flashcards
Which other organs is the pancreas attached to?
Spleen
Duodenum
Which cells make up the endocrine part of the pancreas?
Islets of Langerhan cells
2/3 of the islet cells are beta cells. What does these beta cells secrete?
Insulin
What stimulates the release of insulin?
Eating of food->converted to glucose -> increase in blood glucose -> insulin release
What is the pathology behind type 1 diabetes?
The body cannot distinguish own cells from other cells so there is an autoimmune attack on the pancreatic beta cells
Which cells destroy the pancreatic beta cells in the autoimmune response?
Lymphocytes or cytotoxic T cells
What happens when there is destruction of the islet cells?
Decreased secretion of insulin as beta cells undergo fibrosis and scarring and cannot produce it
The aetiology of type 1 diabetes isn’t really known but what is it a combination of?
Genes and environment
Again, the aetiology pf type 2 diabetes isn’t fully know but what is it a combination of?
Reduced tissue sensitivity to insulin
Inability to secrete high levels of insulin
Describe how obesity can lead to type 2 diabetes.
In obesity, there are more adipocytes in the body.
This increases free fatty acids in the blood.
This leads to decreased insulin receptor sensitivity as more insulin is needed to get all the FFA ‘s into the cell
What happens when the pancreatic beta cells are destroyed due to autoimmune destruction? (type 1 diabetes)
Decreased capacity to produce glucose, increasing glucose levels
Describe how insulin secretion balance leads to type 2 diabetes.
Insulin secretion does not increase enough to counteract insulin resistance caused by central adiposity
Which genes lead to type 2 diabetes?
Genes involved in causing inadequate ‘high level’ insulin secretion by beta cells
->not by adiposity genes causing obesity
What reduction in life expectancy is seen in those with type 2 diabetes?
Life expectancy reduced by 5-10yrs
In those with type 2 diabetes, what is the most common cause of death?
Myocardial infarction
Diabetes accelerates atherosclerosis related conditions such as?
Coronary heart disease
MI
Atherothrombotic stroke
How is atherosclerosis accelerated in those with diabetes?
Glucose attaches to a low density lipoprotein, preventing it from binding to it’s receptor
This interferes with the removal and protein and lipid, causing hyperlipidaemia
Lipids are then disposed in the vessels and this causes atherosclerosis
Accumulation of which substances in vessels, like arterioles, is found in the vessels in those with diabetes?
Plasma proteins, like albumin, and connective tissue, like collagen
What does narrowing of arterioles lead to?
Poor blood flow and ischaemia
Arteriolar disease is also called hyaline change. Which parts of the body are most affected by hyaline change?
Kidneys
Peripheral tissue e.g. foot
Eyes
How many times more likely is a patient with diabetes to require an amputation compared to someone who does not have diabetes?
40x more likely
How many times more likely is a patient with diabetes to have end stage renal disease compared to someone who does not have diabetes?
25x more likely
How many times more likely is a patient with diabetes to develop blindness compared to someone who does not have diabetes?
20x more likely
How does small vessel disease occur in those with diabetes?
Glucoses are added to proteins- glycosylation
->initially reversible but irreversible if covalent blonds are formed
What glycosylated collagen bind to?
Albumin
->normal collagen does NOT bind to albumin
