Steven G. Kohama

Longer lifespan has contributed to the dramatic increase in both the number and proportion of the elderly in the population. However, advanced age is also associated with a decrease in functionality with an increase in fragility, posing a significant socioeconomic challenge. The nonhuman primate mimics many aspects of human aging and therefore provides an opportunity to examine underlying mechanisms and factors that influence aging.  Understanding these complex interactions can be used to identify targets that may be amenable to therapeutic treatment.

Steven Kohama heads the Primate Aging Resource at ONPRC, whose goals are to expand and support basic and clinically-related research in the field of aging using the nonhuman primate. Both goals are complementary, as expanding our understanding of basic mechanisms that underlie senescence can help identify interventions that can alleviate age-related functional decline. The recognition that aging research will be critical for addressing the needs of the expanding aged population, coupled with widespread scientific interest, has helped to identify aging as an important cornerstone of research at ONPRC.

Aging research at ONPRC, like aging itself, encompasses a wide breadth of areas. Studies have traditionally focused on aspects of reproductive senescence, the decline of immune function, vision, and effects of the central nervous system.  These studies have focused on a variety of manipulations, including hormone and growth factor therapy. More recently, the effects of lifestyle have been examined, including those of diet on aged animals and the effect on metabolism. Models of neurodegeneration, such as cerebral ischemia have also been recently developed. Many of these areas of study are multi-disciplinary, such as the exploration of reproductive neuroendocrine aging, where the decline of hormone levels has effects on many target organ systems. Coordination and management of the resource and research projects, coupled with the many tools available at the Center (for example, gene array, proteomics, MRI), provides a dynamic and potent environment for aging research.


 Steven Kohama is a Senior Staff Scientist in the Division of Neuroscience and has been Head of the Aging Resource since 1999. He has a B.A. in Biological Sciences from UCLA and a M.S. from CSULA, where he studied the interactions of the reproductive and immune systems. He then studied mechanisms of neuroendocrine aging at the Andrus Gerontology Center at USC, where he received his Ph.D. in the Department of Neurobiology. Post-doctoral work was conducted at ONPRC, concentrating on ovarian steroid hormone effects on gene regulation in the brain. Following a promotion to Staff Scientist in 1994, he has continued to work on age-related changes in the central nervous system.



Bahjat RF, Williams-Karnesky RL, Kohama SG, West GA, Doyle KP, Spector MD, Hobbs TR and Stenzel-Poore M. (2011) Proof of Concept: Pharmacological preconditioning with a Toll-like receptor agonist protects against cerebrovascular injury in a primate model of stroke. J Cerebral Blood Flow Metab. 31:1229-1242. PMID: 21285967

Kohama SG, Rosene DL and Sherman LS. (2012) Age-related changes in human and nonhuman primate white matter: from myelination disturbances to cognitive decline. AGE. 34:1093-1110. PMID: 22203458

Cargill R, Kohama SG, Struve J, Su W, Banine F, Witkowski E and Back S. (2012) Astrocytes in aged nonhuman primate brain gray matter synthesize excess hylauronan. Neurobiol Aging. 33(4):860e13-24. PMID: 21872361

Gesuete R, Kohama SG, Stenzel-Poore M (2014) Toll-like receptors and ischemic brain injury. J Neuropathol Exp Neurol. 73:378-386. PMID: 24709682

Khan AR, Cornea A, Leigland LA, Kohama SG, Jespersen SN, Kroenke CD (2015) 3D structure tensor analysis of light microscopy data for validating diffusion MRI. NeuroImage 111:192-203. PMID: 25665963


See a full listing of Dr. Kohama's publications.