Oxygen diffusion-enhancing compound
An oxygen diffusion-enhancing compound is any substance that increases the availability of oxygen in body tissues by influencing the molecular structure of water in blood plasma and thereby promoting the movement (diffusion) of oxygen through plasma. Oxygen diffusion-enhancing compounds have shown promise in the treatment of conditions associated with hypoxia (a lack of oxygen in tissues) and ischemia (a lack of oxygen in the circulating blood supply). Such conditions include hemorrhagic shock, myocardial infarction (heart attack), and stroke.
One of the first substances that was reported to produce an oxygen diffusion-enhancing effect was crocetin, a carotenoid that occurs naturally in plants such as crocus sativus, and is related to another carotenoid, saffron. Saffron has been used culturally (e.g., as a dye) and medicinally since ancient times.
Trans sodium crocetinate (TSC), a synthetic drug containing the carotenoid structure of trans crocetin has been extensively investigated in animal disease models and in human clinical trials. Clinical trials of TSC have focused on testing the compound's effectiveness in sensitizing hypoxic cancer cells to radiation therapy in patients with glioblastoma, an aggressive form of brain cancer.
TSC, which is being developed by Diffusion Pharmaceuticals, has been shown to enhance the oxygenation of hypoxic tumor tissue  and belongs to a subclass of oxygen diffusion-enhancing compounds known as bipolar trans carotenoid salts.
Mechanism of action
Oxygen diffusion-enhancing compounds are thought to act by exerting hydrophobic forces that interact with water molecules. These interactions result in greater hydrogen bonding among water molecules, which constitute the majority of the blood plasma medium. As hydrogen bonding increases, the overall molecular structure of water in the plasma becomes more lattice-like, a phenomenon known as structure building. Structure building reduces resistance to the movement of oxygen through plasma via diffusion. Since blood plasma offers the major barrier for oxygen to move from the red blood cells and into the tissues, the more structured character of water imparted by the oxygen diffusion-enhancing compound will enhance movement into tissues.
Computer simulations have shown that TSC specifically can increase the transport of oxygen through water by as much as 30 percent.
- US patent 8206751, Gainer J, "New Class of Therapeutics that Enhance Small Molecule Diffusion", issued 2009-04-30
- Gainer, J (2008). "Trans-sodium crocetinate for treating hypoxia/ischemia". Expert Opinion in Investigational Drugs 17 (6): 917–924. doi:10.1517/135437220.127.116.117.
- Gainer J, G.M. Chisolm III (1974). "Oxygen diffusion and atherosclerosis". Atherosclerosis 19 (1): 135–138. doi:10.1016/0021-9150(74)90049-5. PMID 4810465.
- Abdullaev F, Espinosa-Aguirre J (2004). "Biomedical properties of saffron and its potential use in cancer therapy and chemoprevention trials". Cancer Detection and Prevention 28 (6): 426–432. doi:10.1016/j.cdp.2004.09.002. PMID 15582266.
- Lapchak P, (2010). "Efficacy and safety profile of the carotenoid trans sodium crocetinate administered to rabbits following multiple infarct ischemic strokes: A combination therapy study with tissue plasminogen activator". Brain Research 1309: 136–145. doi:10.1016/j.brainres.2009.10.067. PMID 19891959.
- "Safety and Efficacy Study of Trans Sodium Crocetinate (TSC) With Concomitant Radiation Therapy and Temozolomide in Newly Diagnosed Glioblastoma (GBM)". ClinicalTrials.gov. November 2011. Retrieved 18 September 2012.
- Sheehan, Jason et al. (2008). "Use of trans sodium crocetinate for sensitizing glioblastoma multiforme to radiation". Journal of Neurosurgery 108 (5): 972–978. doi:10.3171/JNS/2008/108/5/0972. PMID 18447715.
- US patent 7919527, ": Bipolar trans carotenoid salts and their uses", issued 2011-04-05
- Laidig, K.E., J.L. Gainer, V. Daggett (1998). "Altering Diffusivity in Biological Solutions through Modification of Solution Structure and Dynamics". Journal of the American Chemical Society 120 (36): 9394–9395. doi:10.1021/ja981656j.
- Cannon, Joseph G (1999). Pharmacology for Chemists. New York: Oxford University Press. ISBN 978-0841235243.
- Manabe H et al. (2010). "Protection against focal ischemic injury to the brain by trans-sodium crocetinate". Journal of Neurosurgery 113 (4): 802–809. doi:10.3171/2009.10.JNS09562. PMC 3380430. PMID 19961314.
- Starr, Cecie; McMillan, Beverly (2012). Human Biology (9th ed.). ISBN 978-0840061669.