Suspended animation-like state protects from lethal hypoxia Journal Club of Life Sciences 27 th May...
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Transcript of Suspended animation-like state protects from lethal hypoxia Journal Club of Life Sciences 27 th May...
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