Mitochondrial function in health and disease

Question 1

What is the oxidative phosphorylation consist of?

Answer 1

Electron transport chain

ATPase => generating ATP (energy)

Question 2

What functions does the mitochondria have?

Answer 2

1. involved in many metabolic pathways (phospholipid synthesis, folate metabolism, synthesis of steroid hormones, haem metabolism, amino acid and nucleotide metabolism)
2. programmed cell death (apoptosis)
3. Ca2+ buffering
4. heat production in brown fat (BAT)

Question 3

What is the dynamics of mitochondrias?

Answer 3

Capable of fusion and fission

Question 4

3 things to say about the mitochondrial genome?

Answer 4

• small circular genome
• 13 polypeptides all for oxidative phosphorylation (13 OXPHOS subunits) encoded by DNA, 22tRNAs & 2 rRNAs encoded by mitochondrial DNA
• strictly maternal inheritance

Question 5

What is primary mitochondrial diseases?

Answer 5

defects in the final stages of mitochondrial energy production => caused by mutations

Question 6

What is secondary mitochondrial diseases?

Answer 6

Due to factors such as ischemia, diabetes, cardiovascular diseases, etc. => caused by functional problems

Question 7

What is the particularity of primary mitochondrial diseases?

Answer 7

One mutation can have different manifestations, different mutations can have the same manifestation
=> heterogeneous disorders

Question 8

Transmission of mtDNA diseases in % (from the mother)?

Answer 8

It is possible that the mother has 50% mitochondrion mutations but she is healthy because the other half is compensating. But if the % of mutations is too much (like 80%) then manifestations can appear

Question 9

What are the 4 strategies to prevent transmission of mtDNA mutations?

Answer 9

1. Normal conception (and hope for the best)
2. Oocyte donation (baby is from another mother)
3. Preimplantation diagnosis (select healthy embryo)
4. Mitochondrial replacement (remove nucleus of donor oocyte and insert nucleus of mother and father, then implant in mother)

Question 10

2 diagnosis of mitochondrial disease?

Answer 10

Muscle biopsy or plasma/urine analysis

Both are very cost-efficient and fast

Question 11

Treatment for primary mitochondrial diseases?

Answer 11

There is no perfect treatment!

Stuff like diet, antioxidants, avoid stress, etc.

Question 12

How does secondary mitochondrial diseases function in ischaemia and what are the causes?

Answer 12

Stop of oxygen flow => electrons are free => more ROS => tissue damage
After when sudden oxygen overflow => more superoxide because adds on all the free electrons => even more tissue damage
Causes: tobacco, physical inactivity, bad diet, lot of alcohol