Hyperpolarized singlet lifetimes of pyruvate in human blood and in the mouse.
Hyperpolarized NMR is a promising technique for non-invasive imaging of tissue metabolism in vivo. However, the pathways that can be studied are limited by the fast T1 decay of the nuclear spin order. In metabolites containing pairs of coupled nuclear spins-1/2, the spin order may be maintained by exploiting the non-magnetic singlet (spin-0) state of the pair. This may allow preservation of the hyperpolarization in vivo during transport to tissues of interest, such as tumors, or to detect slower metabolic reactions. We show here that in human blood and in a mouse in vivo at millitesla fields the (13)C singlet lifetime of [1,2-(13)C2]pyruvate was significantly longer than the (13)C T1, although it was shorter than the T1 at field strengths of several tesla. We also examine the singlet-derived NMR spectrum observed for hyperpolarized [1,2-(13)C2]lactate, originating from the metabolism of [1,2-(13)C2]pyruvate.
Department of Biochemistry, University of Cambridge, UK, and Cancer Research UK Cambridge Research Institute, Cambridge, UK.
Irene
I
Marco-Rius
Michael C D
MC
Tayler
Mikko I
MI
Kettunen
Timothy J
TJ
Larkin
Kerstin N
KN
Timm
Eva M
EM
Serrao
Tiago B
TB
Rodrigues
Giuseppe
G
Pileio
Jan Henrik
JH
Ardenkjaer-Larsen
Malcolm H
MH
Levitt
Kevin M
KM
Brindle
D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D060526:Magnetic Fields; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008810:Mice, Inbred C57BL; D019289:Pyruvic Acid / Q000097:blood*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D012996:Solutions; D013997:Time Factors
D012996:Solutions; D012710:Serum Albumin, Bovine; D019289:Pyruvic Acid
blood; dynamic nuclear polarization; hyperpolarization; lactate; long-lived states; longitudinal relaxation time; pyruvate; relaxation