Experimental approaches to evaluating the role of environmental factors in the development of cardiovascular disease.

Epidemiologic studies have suggested factors in drinking water influence on the human cardiovascular system. A clear identification of the factors involved requires more invasive techniques and more strict experimental controls than can usually be applied in epidemiologic studies. Consequently laboratory animals are often used to expand and support epidemiologic data. For laboratory purposes cardiovascular toxicology must be broken down to effects on the myocardium, the vasculature and the kidney. Further division may be necessary to take into account the influence of the neuroendocrine system or other systems that influence the function of the cardiovascular system. Since environmental influences upon the cardiovascular disease are relatively subtle (versus the acute effects of some drugs) it is assumed that major difficulties are chronic in nature. Accordingly, it is suggested that laboratory experimentation focus on either chronic toxin exposure or short-term exposure to stressed or genetically susceptible animals. A variety of in vivo and in vitro tests may be necessary to relate the toxicity realized in animals to what might be expected in man. Wide species differences with respect to the susceptibility of particular target tissues must be taken into account to clearly apply the results to man. Similarly, special characteristics of stressed and genetically susceptible animals must be understood to avoid deceptive results.