Diabetes Flashcards
What is type I diabetes mellitus?
Autoimmune destruction of the beta cells in the pancreas which produce insulin
What is the only current therapy for type I diabetes mellitus?
Insulin injection or insulin pumps to maintain blood glucose
The prevalence of type I diabetes is increasing. T/F?
True
Type 2 diabetes is associated with obesity. T/F?
True
What is type II diabetes mellitus?
Insulin resistance where tissues are no longer sensitive to endogenous insulin
How do sulphonylureas act as hypoglycaemic drugs?
These inhibit ATP-sensitive potassium channels to increase the release of insulin
Give examples of sulphonylureas which are used clinically as hypoglycaemic drugs?
Glibenclamide Gliclazide Glimepiride Tolbutamide Glipizide
Metformin is an example of a biguanide which is used as a hypoglycaemic drug. How does it work?
It mimics insulin by inhibiting hepatic gluconeogenesis
How do thiazolidinediones work as a hypoglaemic drug?
They stop the inappropriate deposition of lipid in non-adipose tissue by acting as a ligand to stimulate the expression of genes involved in TAG storage. This improves insulin sensitivity
Give an example of a thiazolidineione used as a hypoglycaemic drug?
Pioglitazone
What are incretins?
GI hormones which potentiate insulin secretion
Give examples of incretins
Glucagon like peptide 1
gastric inhibitory peptide
Which enzyme rapidly inactive incretins?
dipeptidyl peptidase 4 (DDP-4)
Incretins are endogenous molecules which potentiate the effects of insulin but are rapidly broken down by DDP-4. Give examples of incretin mimics which are used as hypoglycaemic drugs as they are not cleaved by DDP-4?
Exenatide
Liraglutide
Give examples of drugs which inhibit DDP4 to increase endogenous incretin mediated increase in insulin secretion?
Sidagliptin
Vildagliptin
Canagliflozin, dapagliflozin and empagilflozin are SGLT2 inhibitors. How do these work to reduce hyperglycaemia?
These inhibit renal reabsorption glucose through SGLT2
What type of. hypersensitivity reaction is type 1 diabetes mellitus?
Type 4 cell mediated hypersensitivity
What antibodies may exist in a patient with type I diabetes?
GAD65 - against glutamic acid decarboxylase
IAA - against insulin
I-A2 against tyrosine phosphatase like molecule
ICA - against islet cells
ZnT8 - against beta cell specific zinc transporter
Beta cell destruction proceeds for months or years without detection as inflammation of the beta cells. Often, what percentage of beta cells needs to be destroyed before hyperglycaemia develops?
80-90%
How does the lack of insulin in type 1 diabetes lead to hyperglycaemia?
GLUT4 not translocated onto muscle, liver or adipose cells so there is limited glucose uptake by these cells. This results in decrease glycogenesis and protein synthesis and an increase in glycogen-lysis, gluconeogenesis and lipolysis
Which HLA genes provide a genetic susceptibility to type 1 diabetes?
HLA-DR3
HLA-DR4
As well as genetic factors, environmental factors have been implicated in the development of type 1 diabetes mellitus. What are these environmental factors?
Congenital rubella syndrome Human enteroviruses Vitamin D deficiency Wheat proteins (gluten) Cow's milk Psychological stress
What are some of the microvascular complications of diabetes?
retinopathy
neuropathy
nephropathy
What are some of the microvascular complications of diabetes?
Cardiovascular, cerebrovascular and peripheral vascular disease