|Santosh K. Katiyar, Ph.D.|
University of Alabama at Birmingham
B.S. Chemistry, Zoology and Botany, 1971
RESEARCH INTEREST IN CUTANEOUS BIOLOGY
Dr. Katiyar has been working for the last 13 years on different aspects of cutaneous biology, such as immunology, photobiology, photocarcinogenesis and photoaging, as detailed below:
Causes, mechanism and preventive approaches of skin carcinogenesis
Dr. Katiyar's interest is to study and/or determine the causes, mechanisms and preventiom of chemical and solar ultraviolet (UV) radiation induced skin carcinogenesis (photocarcinogenesis). It is well documented that chronic exposure of solar UV radiation to human skin is primarily responsible for approximately 1.3 million new cases of squamous and basal cell carcinoma every year in the USA, thus making it the most prevalent environmental carcinogen known for humans. UV radiation is a potent producer of reactive oxygen species and can act as a tumor initiator, tumor promoter and complete carcinogen as well. Dr. Katiyar is trying to develop newer and effective chemopreventive agents, particularly dietary botanicals that can prevent the risk of UV carcinogenesis in humans. To develop newer and more effective chemopreventive agents, we use in vivo animal and human model systems and in vitro cell culture systems.
Causes, mechanism and preventive approaches of cutaneous photoaging
As in other organ systems, aging in the skin results in progressive dysfunction and diminution of the radiation reserve capacity under stress, rendering the skin more susceptible to injury and diseases. Clinical conditions associated with age-dependent dysfunction include increased ease of wounding, poor wound healing, skin cancer and infectious disease susceptibility, autoimmune reactivity to skin and drugs. The progressive susceptibility to these conditions with age is due to a combination of aging processes attributable to both chronologic (intrinsic) aging, and photoaging (extrinsic damage from the environment, mainly repeated solar light exposure). Clinically the photoaging component of skin aging accounts for the development in sun-exposed areas of wrinkling, mottled hyperpigmentation and depigmentation, coarsening of the skin, roughness, poor elastic recoil, and bruisability. These conditions adversely affect self-esteem and psychosocial well being. By contrast, intervention to reduce the stigmata of photoaging can result in improved quality of life and functionality in the elderly. Dr. Katiyar also considers that accelerated photoaging of the skin is also due to impaired oxidative defense system.
Keeping these factors under consideration, Dr. Katiyar is developing new and effective chemopreventive agents, particularly from dietary sources, which can inhibit the process of skin aging and photoaging. For this purpose, he is working on various polyphenols obtained from green tea and grape seeds and using in vitro and in vivo model systems. He determined that topical application of polyphenols from green tea on animal skin protects from UV-induced adverse biological effects associated with the photoaging of the skin.
GRANTS SUPPORT CURRENT:
(1) 1R01 AT002536-01A2 (PI: Katiyar)
The major goal of this project is to determine and define the mechanism of immunoprotective and anti-photocarcinogenic effects of green tea polyphenols (GTPs) using genetically modified mouse models.
Period: 9/1/2006 - 8/31/2011
The major goal of this project is to determine the immunomodulatory and anti-photocarcinogenic effects of dietary grape seen proanthocyanidins (GSPs) using genetically modified mouse models. In this study we will demonstrate whether the chemopreventive effect of GSPs against photocarcinogenesis is mediated through the induction of interleukin-12 and DNA repair.
Period: 04/01/05 - 06/30/2012
(3) Research Career Scientist Award, Veterans Administration (PI: Katiyar)
This Research Career Scientist award is given by the Veterans Administration and supports a major part of the annual salary of Dr. Katiyar.
Period: 04/01/2009 - 03/31/2014
The goal of this study is to identify epigenetic mechanisms by which green tea may act to prevent UV-induced skin cancer. The studies will include examining the effect of green tea polyphenols on UV-induced DNA hypermethylation and histone modifications in the mouse skin and skin tumors.
Period: 03/01/2010 - 02/28/2012
The goal of this study is to identify the chemopreventive mechanism of ultraviolet radiation (UV)-induced skin carcinogenesis by silymarin, a phytochemical from milk thistle (Silybum marianum). The studies will include the effect of silymarin on UV-induced immunomodulatory effects including effector and regulatory T-cells in skin carcinogenesis.
Period: 07/01/2010 - 12/31/2014