UNDERSTANDING MITOCHONDRIA AND THEIR ROLE IN HEART DISEASE

What are mitochondria?

 

Mitochondria are the equivalent of the engine in your car, except they are the engine or power house for the human cell. In your car you put in fuel, which the engine ignites to release energy to pump the pistons, which drive the car and recharge the electrical capacity of your car via the battery.

 

If the car engine deteriorates; because its old, because there is an underlying defect, because it has been exposed to the wrong fuel, because its been exposed to the wrong environment, it will eventually break.

 

Similarly, inside almost every cell in your body there its own little engine, the mitochondria; nutrients and compounds arrive at the cell and are transported to the mitochondria which then converts these into the energy to make the cell work. If your mitochondria stop functioning properly, they signal cell necrosis or inappropriate death and the cell stops doing its job.

Mitochondrial dysfunction and inappropriate cell death

 

Because Mitochondria are a critical and sensitive component of your cellular activity, anything that significantly disturbs its balance, function and introduces molecules not supposed to be in it creates dysfunction.

 

The dysfunction, over stresses the mitochondria and they lose fine control; one key component of this is the channels (also known as pores) in the mitochondria, which when dysfunctional stay perpetually open, as opposed to a regulated open and closed state. The mitochondria then swell, stop working, the cell loses its energy source and is signalled to die.

 

So for example if you eat the wrong food, drink too much, inhale smoke or other chemicals over a protracted period of time, what appears to be dysfunction in one or two cells, actually means over time there is dysfunction in hundreds of millions of them. If these cells are in your heart, this means that there are lots of dead cells in your heart; if those dead cells are your heart muscle cells, it means your heart will not work as well. This can and does lead to heart failure.

Cardiovascular disease, inappropriate cell death and heart failure

 

The process that gives rise to eventual heart failure is a long, slow degenerative process; in many cases we are only treating the disease after significant damage has been done, which is why in modern health care we now put as much effort into education on prevention of heart disease as we do into therapeutic development. However we cannot prevent getting old, ageing is a natural process, the dynamics of which vary greatly between people so we are always going to need to find new treatments.

 

The process itself starts with an injury to a blood vessel, the vascular part of cardiovascular disease. This injury, also known as an ischemic event, can be due to vein clogging due to smoking or diet, an associated disease such as diabetes, or simply wear and tear on the vessel; it puts stress on the blood vessel, results in a localised change in blood pressure which results in lower amounts of nutrients arriving at the surrounding cells. This damages the cells, both physically and biochemically by inducing mitochondrial dysfunction and results in cell death.

 

If this occurs in the heart, it is a problem, because your heart works non-stop, it needs lots of oxygen and nutrients, if blood flow is restricted irreversible injury occurs within 20 minutes in the heart muscle. Imbalance occurs in the cells localised to the vessel and cells die, but unlike other organs there is no mechanism to replace dead cells, so you are left with dead cells in the heart, this causes the heart to work harder, strains other blood vessels in the heart and starts a vicious cycle, in which damage induces damage.

 

‘If we can stop the vicious cycle by restoring function back to the cell so it doesn’t die, the vascular system will find a new way to provide it with nutrients.’