suspended animation-like state protects from lethal hypoxia journal club of life sciences

Suspended animation-like state protects from lethal

hypoxia

Journal Club of Life Sciences27th May 2010Brian Lassen

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

(S2O3-, Fe) H+ gradient

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

properties



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

S2-, SO3-, NH3 provide electrons

(S2O3-, 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



HypothesisIs sulphide a critical buffer in oxygen consumption

after exposure to hydrogen sulphide?



Method

Pretreatment150 ppm H2S and 20.3% O2, 20 min

No Pretreatment20.3% O2

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?



Method

Pretreatment150 ppm H2S 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?


Suspended animation-like state protects from lethal hypoxiaCan mice survive in less than 5% oxygen after pre-exposure?

Method Result

No animals survivedAll animals survived

Figure 3

No PT20.3% O2, 20 min

PT150 ppm H2S and 20.3% O2, 20 min

PT +1150 ppm H2S and 20.3% O2, 20 min

5% No PT5% O2, 1 hour

5% PT5% O2, 1 hour

4% PT4% O2, 1 hour

3% PT+13% O2, 1 hour

4% PT+14% O2, 1 hour

5% O2, 1 hour


Suspended animation-like state protects from lethal hypoxiaMetabolic markers: CO2 production during hypoxia correlate with survival time?

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

Method ResultFigure 4No PT

20.3% O2, 20 min

PT150 ppm H2S and 20.3% O2, 20 min

PT +1150 ppm H2S and 20.3% O2, 20 min

5% No PT5% O2, 1 hour

5% PT5% O2, 1 hour

4% PT4% O2, 1 hour

4% PT+14% O2, 1 hour

5% O2, 1 hour

No animals survivedAll animals survived

CO2 reduction seems important to survival

Figure 4



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)



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



www.ted.comMark Roth

Next Journal Club of Life Sciences

Tõiv HaljasorgMass spectrometry,

Part II10th June 2010

suspended animation-like state protects from lethal hypoxia journal club of life sciences

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