Diabetes

Question 1

diabetes mellitus is…

Answer 1

the most common endocrine disease

Question 2

what type of disease is DM?

Answer 2

complex, metabolic disease

Question 3

what metabolism is affected?

Answer 3

proteins, lipids, CHO

Question 4

what cells produce insulin? what cells produce glucagon?

Answer 4

beta cells in Islets of Langerhans in pancreas produce insulin; alpha cells produce glucagon

Question 5

what happens with insulin in DM?

Answer 5

• hypoactivity (qualitative or quantitative)
• secretion of insulin is defective
• affects glucose homeostasis

Question 6

absolute deficiency

Answer 6

absent insulin or a very little amount

Question 7

relative deficiency

Answer 7

insulin is present, but is not effective

Question 8

what does DM impact?

Answer 8

cardiac, renal, ocular, nervous system

Question 9

will complications develop?

Answer 9

yes, will be acute, but can be delayed if you control the symptoms

Question 10

is DM life-threatening?

Answer 10

if its not controlled

Question 11

Type 1 DM

Answer 11

• 10%
• absolute insulin deficiency
• beta cells are absent or are damaged by autoimmunity

Question 12

Type 1A

Answer 12

• 90-95%
• immune-mediated
• autoimmune destruction of beta cells

Question 13

Type 1B

Answer 13

• 5-10%
• not autoimmune
• idiopathic destruction of beta cells

Question 14

Type 2 DM

Answer 14

• 90%
• less severe; beta cells can still prod. insulin
• receptors do not respond to insulin

Question 15

LADA

Answer 15

• latent autoimmune diabetes of the adult

- type 1 diabetes developing gradually and appearing later in life

Question 16

MODY

Answer 16

• maturity onset of diabetes in the young

- type 2 diabetes developing in early life due to poor lifestyle

Question 17

gestational diabetes

Answer 17

hyperglycemia during pregnancy, but normoglycemic postpartum

Question 18

drug-induced diabetes

Answer 18

ex. steroids

Question 19

what is the etiology of both types?

Answer 19

complex trait; polygenic - requiring multiple defective genes, and environmental factors such as viral infection

Question 20

Type 1 etiology: which chromosome are the MHC genes on?

Answer 20

chromosome 6 (40% have defective MHC genes)

Question 21

Type 1 etiology: what do the MHC genes do?

Answer 21

code for proteins that sit on the surface of cells to show them pathogens (so that defense cells can recognize the pathogens)

Question 22

Type 1 etiology: what is MHC?

Answer 22

major histocompatibility complex –> the cell surface proteins used in the acquired (non-innate) immune system to recognize foreign molecules

Question 23

Type 1 etiology: MHC binds to _____ and does what on the cell surface for recognition by what?

Answer 23

peptide fragments; displays them on cell surface for recognition by T cells

Question 24

Type 1 etiology: MHC II are on ______ ________ ______ and present ________ _________.

Answer 24

antigen presenting cells (DC, B cells, macrophages); extracellular peptides

Question 25

Type 1 etiology: MHC 1 holds…

Answer 25

self antigens identifying the cell (presents intracellular peptides)

Question 26

Type 1 etiology: what do some viruses do and why? What cells respond to this?

Answer 26

• reduce the amount of MHC I so they can hide from defense cells and not be detected as foreign
• NK cells destroy all cells without reduced MHC I

Question 27

Type 1 etiology: where is the insulin gene?

Answer 27

on chromosome 11 (10% have defective I gene)

Question 28

Type 1 etiology: what does the insulin gene do?

Answer 28

• codes for a protein that regulates division and function of beta cells
• impacts insulin prod.

Question 29

Type 1 etiology: what risk is there with type 1 DM?

Answer 29

familial risk (10x increased)
- if your sibling has it, you are 10x more likely to develop it

Question 30

Type 1 etiology: what type of hypersensitivity affects what antigen

Answer 30

T cell hypersensitivity to beta cell antigen

Question 31

Type 2 etiology: what is the component involved?

Answer 31

strong, unclear genetic component

Question 32

Type 2 etiology: in MODY, which gene on which chromosome is affected?

Answer 32

glucokinase gene on chr 7 (in 50% cases)

Question 33

Type 2 etiology: what does the glucokinase gene code for?

Answer 33

a protein (ie. glucokinase enzyme)

Question 34

Type 2 etiology: glucose + phosphate = ?

Answer 34

phosphorylated glucose; allows glucose to be converted in glycogen and stored

Question 35

Type 2 etiology: explain phosphorylation

Answer 35

brought on by glucokinase, but if gene coding for this liver enzyme is defective then phosphorylation
cannot occur. Insulin will take in glucose, but it will go right back into the bloodstream, resulting in hyperglycemia.