Gideon St Helen, PhD
The focus of my research program in the Division of Clinical Pharmacology, as shown in the image below, is the utility and evaluation of biological markers (biomarkers) of tobacco use and exposure for epidemiology, risk assessment, product regulation, and identification of susceptibility factors.
1. Epidemiology: We identify traditional and novel tobacco biomarkers that may better predict tobacco-related health outcomes. These include breakdown products of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), tobacco-specific nitrosamines, and nicotelline, a tobacco-specific compound found in the particulate phase of tobacco smoke.
2. Risk assessment: We assess exposure to toxic and carcinogenic tobacco compounds by measuring their biomarkers in nonsmoking children and adults, and users of various tobacco products such as cigarettes, hookahs, e-cigarettes, and smokeless tobacco products. The levels of biomarkers of toxic and carinogenic compounds can be used to quantify risk of diseases such as cancer.
3. Product regulation: An important component of my research is providing the Food and Drug Administration with critical data to inform its tobacco product regulatory function. The research in this area involves primarily clinical studies to assess intake of tobacco-related compounds and toxicants from various tobacco products. A priority area is the clinical pharmacology of electronic cigarettes and new technologies under development by the tobacco industry. We investigate the addictive potential of e-cigarettes through assessment of nicotine pharmacokinetic parameters, intake of toxic compounds such as carbonyls, and e-cigarette features that affect nicotine delivery and dependence.
4. Susceptibility factors: An exciting part of my research program entails using tobacco biomarkers to assess factors that increase susceptibility to nicotine dependence and disease outcomes. Part of this effort focuses on understanding racial disparities in tobacco-related disease outcomes, with emphasis on the question, why do African Americans account for more lung cancer incidence than most other racial groups although >50% of them are light smokers? We focus on the role of genetic variation and nicotine metabolism on toxicant intake and smoking behavior among racial groups and sexes.
Studies of cannabis pharmacology have recently been added to my research program. These include studies to understand the safety of various forms of cannabis administration, such as novel electronic delivery systems, as well as studies on short-term cardiovascular effects of smoking and vaping cannabis compared to smoking tobacco cigarettes. Other research interests include understanding the pharmacologic interactions of various forms of co-administration of cannabis and tobacco, such as blunts and spliffs.