Faculty Appointments: 
Professor of Biochemistry and Biophysics at University of Pennsylvania School of Medicine (2009– present)
Adjunct Assistant Professor of Pediatrics at University of Pennsylvania School of Medicine (1981 – 1984)
Research Assistant Professor of Pediatrics at University of Pennsylvania School of Medicine (1984 – 1987)
Research Associate Professor of Pediatrics at University of Pennsylvania School of Medicine (1987 – 1994)
Research Professor of Pediatrics at University of Pennsylvania School of Medicine (1994– present)
Office Location: 
CHOP, Division of Metabolism and Genetic 34th & CIVIC CENTER 4399

As a director of the Metabolomic Core Facility at Children?s Hospital of Philadelphia, I have collaborated and contributed to many projects investigating metabolomic profiling in normal and disease states such as, neurological dysfunction caused by traumatic brain injury, the molecular and metabolomic profiling in animal models of cancer before and after chemotherapy treatment, the molecular and metabolomic characteristic of renal carcinoma or the mTOR and protein homeostasis. As a member of the Institute of Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, I have been involved in various projects dealing with hepatic metabolism and insulin resistance, obesity or diabetes. My research is unique in its use of in vivo and in vitro model systems, and methodological approach including, molecular biology, stable isotopes, liquid chromatography-mass spectrometry and Nuclear Magnetic Resonance to determine body composition, metabolic fluxes and metabolomic profiling.

I am a biochemist with a long-standing interest in research related to metabolic disorders, including neurochemical aberrations, defects in hepatic nitrogen metabolism, obesity, fatty liver disease, diabetes and pathogenic mitochondrial integrity and function. A special emphasis is on development of pharmacotherapeutic intervention to mitigate metabolic derangements. I have pursued studies to understand the benefits and risks of drugs for treatment of obesity-induced metabolic derangements, impaired hepatic nitrogen metabolism, type-2-diabetes, the regulation of insulin release from ß-cells, the benefits of ketogenic diet in cases of neurochemical aberrations or amino acids diet in case of traumatic brain injury.

Ph.D., Life Science, Weizmann Institute of Science, Rehovot, Israel (1979)
M.Sc., Life Science, Hebrew University, Jerusalem, Israel (1974)
B.Sc., Life Science, Bar Ilan University, Ramat Gan, Israel (1972)
Selected Publications
Li C, Liu C, Nissim I, Chen J, Chen P, Doliba N, Zhang T, Nissim I, Daikhin Y, Stokes D, Yudkoff M, Bennett MJ, Stanley CA, Matschinsky FM, Naji A.. Regulation of glucagon secretion in normal and diabetic human islets by ?-hydroxybutyrate and glycine.. J. Biol. Chem.. Vol 288(3) . 2013 Feb 8:3938-3951.
Cang C, Zhou Y, Navarro B, Seo YJ, Aranda K, Shi L, Battaglia-Hsu S, Nissim I, Clapham DE, Ren D.. mTOR regulates lysosomal ATP-sensitive two-pore Na(+) channels to adapt to metabolic state.. Cell. Vol 152(4) . 2013 Feb. 14:778-790.
Nissim I, Horyn O, Ilana Nissim, Daikhin Y, Wehrl SL,Yudkoff M and Matschinsky FM:. Effects of a glucokinase activator onhepatic intermediary metabolism: study with 13C-isotopomer-based metabolomics.. Biochem J.. Vol 444. 2012:537-551.
Changhong Li, Chengyang Liu, Itzhak Nissim , et al.:. Regulation of Glucagon Secretion in Normal and Diabetic Human Islets by Gamma-Hydroxybutyrate and Glycine. J Biol Chem,. 2012.
Falk MJ, Polyak E, Zhang Z, Peng M, King R, Maltzman JS, Okwuego E, Horyn O, Nakamaru-Ogiso E, Ostrovsky J, Xie LX, Chen JY, Marbois B, Nissim I, Clarke CF, Gasser DL. Probucol ameliorates renal and metabolic sequelae of primary CoQ deficiency in Pdss2 mutant mice. EMBO Mol Med.. Vol 7. 2011:410-427.
Nissim I, Horyn O, Nissim I, Daikhin Y, Caldovic L, Barcelona B, Cervera J, Tuchman M,Yudkoff M.. Down-regulation of hepatic urea synthesis by oxypurines: xanthine and uric acid inhibit N-acetylglutamate synthase. J Biol Chem.. Vol 286. 2011:22055-22068.
Li C, Chen P, Palladino A, Narayan S, Russell LK, Sayed S, Xiong G, Chen J, Stokes D, Butt YM, Jones PM, Collins HW, Cohen NA, Cohen AS, Nissim I, Smith TJ, Strauss AW, Matschinsky FM, Bennett MJ, Stanley CA.. Mechanism of hyperinsulinism in short-chain 3- hydroxyacyl-CoA dehydrogenase deficiency involves activation of glutamate dehydrogenase. J Biol Chem.. Vol 285. 2010:1806-1818.
Nissim I, , Horyn O, Daikhin Y, Nissim I, Luhovyy B., Phillips, PC, and Yudkoff M.. Ifosfamide-Induced Nephrotoxicity: Mechanism and Prevention. Cancer Res. 66. Vol 66. 2006:7824-7831.
Yudkoff M, Ah Mew N, Daikhin Y, Horyn O, Nissim I, Nissim I, Payan I, Tuchman M.. Measuring in vivo ureagenesis with stable isotopes. Mol Genet Metab.. Vol 100. 2010:37-41.