Suspended animation-like state protects from lethal hypoxia Journal Club of Life Sciences 27 th May 2010 Brian Lassen Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Reducing power produced here due to reveresed electron flow driven by H + gradient S 2-, SO 3-, NH 3 provide electrons (S 2 O 3 -, Fe) H + gradient formed here due to H + pumped out of the cell during electron transfers O 2- and S 2- similar properties

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Reducing power produced here due to reveresed electron flow driven by H + gradient S 2-, SO 3-, NH 3 provide electrons (S 2 O 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., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Hypothesis Is sulphide a critical buffer in oxygen consumption after exposure to hydrogen sulphide?

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Method Pretreatment 150 ppm H 2 S and 20.3% O 2, 20 min No Pretreatment 20.3% O 2 5% O 2 Result Normal survival is 15 min. (LD50) Figure 1 Can pre-exposure to H 2 S increase survival in lowered amounts of oxygen?

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Method Pretreatment 150 ppm H 2 S and 20.3% O 2, 20 min 5% O 2, 6 hours 80 ppm H 2 S and 5% O 2, 6 hours Result Figure 2 50 fold drop in metabolic rate Can continued exposure to H 2 S increase survival and metabolic rate in lowered amounts of oxygen?

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Can mice survive in less than 5% oxygen after pre-exposure? MethodResult No animals survived All animals survived Figure 3 No PT 20.3% O 2, 20 min PT 150 ppm H 2 S and 20.3% O 2, 20 min PT ppm H 2 S and 20.3% O 2, 20 min 5% No PT 5% O 2, 1 hour 5% PT 5% O 2, 1 hour 4% PT 4% O 2, 1 hour 3% PT+1 3% O 2, 1 hour 4% PT+1 4% O 2, 1 hour 5% O 2, 1 hour

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Metabolic markers: CO 2 production during hypoxia correlate with survival time? Comparing 5 min. before 5% oxygen exposure to 5 min. after. MethodResult Figure 4No PT 20.3% O 2, 20 min PT 150 ppm H 2 S and 20.3% O 2, 20 min PT ppm H 2 S and 20.3% O 2, 20 min 5% No PT 5% O 2, 1 hour 5% PT 5% O 2, 1 hour 4% PT 4% O 2, 1 hour 4% PT+1 4% O 2, 1 hour 5% O 2, 1 hour No animals survived All animals survived CO 2 reduction seems important to survival Figure 4

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Pre-exposure to H 2 S 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 H 2 S 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., Shock, vol. 27, No. 4, p 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 H 2 S to put mammals into animated state in case of emergencies Experiments are currently (2010) in second phase human trails

Blackstone, E; Roth, M.B., Shock, vol. 27, No. 4, p Suspended animation-like state protects from lethal hypoxia Mark Roth

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