Suspended animation-like state protects from lethal

hypoxia

Journal Club of Life Sciences

27th May 2010

Brian Lassen

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Reducing power produced here due to reveresed electron flow driven by H+ gradient

S2-, SO3-, NH3

provide electrons

(S2O

3-, Fe) H+ gradient

formed here due to H+ pumped out of the cell during electron transfersO2- and S2- similar

properties

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Reducing power produced here due to reveresed electron flow driven by H+ gradient

S2-, SO3-, NH3

provide electrons

(S2O

3-, Fe) H+ gradient

formed here due to H+ pumped out of the cell during electron transfers

Sulphur used to be terminal electron acceptor for respiration

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

HypothesisIs sulphide a critical buffer in oxygen consumption

after exposure to hydrogen sulphide?

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Method

Pretreatment150 ppm H

2S and

20.3% O2,

20 min

No Pretreatment20.3% O

2

5% O2

5% O2

Result

Normal survival is

15 min. (LD50)

Figure 1

Can pre-exposure to H2S increase survival in lowered amounts of oxygen?

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Method

Pretreatment150 ppm H

2S and

20.3% O2,

20 min

5% O2,

6 hours

80 ppm H2S and

5% O2,

6 hours

Result

Figure 2

50 fold drop in metabolic rate

Can continued exposure to H2S increase survival and metabolic rate in lowered

amounts of oxygen?

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Can mice survive in less than 5% oxygen after pre-exposure?

Method Result

No animals survived

All animals survived

Figure 3

No PT20.3% O

2, 20 min

PT150 ppm H

2S and

20.3% O2,

20 min

PT +1150 ppm H

2S and

20.3% O2,

20 min

5% No PT5% O

2, 1 hour

5% PT5% O

2, 1 hour

4% PT4% O

2, 1 hour

3% PT+13% O

2, 1 hour

4% PT+14% O

2, 1 hour

5% O2,

1 hour

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Metabolic markers: CO2 production during hypoxia correlate with survival time?

Comparing 5 min. before 5% oxygen exposure to 5 min. after.

Method Result

Figure 4No PT20.3% O

2, 20 min

PT150 ppm H

2S and

20.3% O2,

20 min

PT +1150 ppm H

2S and

20.3% O2,

20 min

5% No PT5% O

2, 1 hour

5% PT5% O

2, 1 hour

4% PT4% O

2, 1 hour

4% PT+14% O

2, 1 hour

5% O2,

1 hour

No animals survived

All animals survived

CO2 reduction seems important

to survival

Figure 4

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Pre-exposure to H2S seems to increase survival rate of mice in lethan (5%)

hypoxia

Conclusions & Discussion

Pre-treatment in 5% oxygen levels lowers the metabolic rate and enables survival at even lower levels of oxygen

The process of putting mammals in an animated state at low levels of H2S is

reversable without apparent side effects

Perhaps COX can be considered an area of supply and demand in aerobic cells rather than create an imbalance (producing reactive oxygen species)

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

Thought developed further to put mammals in animated state after lethal injuries increasing survival chances by expanding the response period

What is next?

The research team created a liquid based dose of H2S to put mammals into

animated state in case of emergencies

Experiments are currently (2010) in second phase human trails

Blackstone, E; Roth, M.B., 2007. Shock, vol. 27, No. 4, p 370-372

Suspended animation-like state protects from lethal hypoxia

www.ted.comMark Roth

Next Journal Club of Life Sciences

Tõiv Haljasorg

Mass spectrometry, Part II

10th June 2010