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Cells Need Physiologic Simulation

In a typical incubator, cells experience controlled temperature and carbon dioxide levels. However, as we saw in the last post, cells can be out of optimum for long periods of time when handled in a room air biological safety cabinet (BSC).

There are many other factors that are critical for cells. The role of physiologic oxygen in cell culture should not be underestimated.

What is physiologic oxygen?

That depends upon the three L’s of physiology: Location, Location, Location

An excellent review of the critical role of oxygen in human tissues can be found here.

Some key points on the oxygen needs of different cell types in vitro:

• It is tissue location-specific

• It is cell-type dependent at that location

• Oxygen changes can drive gene expression changes through HIF-1

• Hypoxia-Inducible Factor 1 (HIF-1) activity is modulated essentially instantaneously by oxygen changes

• Maintaining unbroken control of oxygen is critical for maintaining cell phenotype In Vitro

We will go into more depth on these points in a later post.

What is pathophysiologic oxygen?

A. Henn , BioSpherix

Oxygen levels that are higher or lower than physiologic oxygen, but the right level of oxygen for your cell type (normoxic) is different from that of other types, therefore the same oxygen level can be lower than normoxic (hypoxic) or higher than normoxic (hyperoxic) for different cell types.

For instance, cells in the upper airway may experience 12-15% oxygen, so levels far below that – say 5% may be hypoxic for that cell type.

The cells in bone or bone marrow experience oxygen levels from 0-4%, depending on how close they are to a blood vessel, so 5% oxygen would be hyperoxic for those cell types.

Even skin, which seems like it should have good air exchange, has an oxygen gradient that is affected by vascular occlusion.

 

A. Henn , BioSpherix

So cells need unbroken physiologically relevant conditions. These cannot be maintained in a room-air environment such as a standard cell culture BSC.

Enclosure of cell handling processes in an environmentally-controlled environment such as a hypoxia hood or barrier isolator is essential for maintaining physiologic simulation in culture.