The challenge of traditional Chinese medicines for allopathic practitioners.

THE STUDY REPORTED BY Zhang et al. (14) in this issue of the American Journal of Physiology-Heart and Circulatory Physiology raises several potentially important issues relating to traditional remedies. Despite their lack of acceptance by opinion makers in the field of clinical medicine, these remedies remain the commonest therapeutic agents used worldwide, and some of them have even found their way into the pharmacopeias of several developed countries. Herbal remedies are approved in Germany and Japan (8). In the United States, it has been reported that 25% of Americans who consult their physician about a serious health problem employ unconventional therapy, but only 70% of these patients inform their physician of such use (3). A recent survey revealed that general practitioners in Scotland currently prescribe herbal medicines more frequently than in the past decade. However, a distinction must be drawn between herbal (i.e., plant derived) remedies and medications used in traditional Chinese medicine. The latter often contains multiple animal products, and the ingredients are usually combined in accordance with principles very different from Western allopathic medicine. Tongxinluo in capsule form is a compound formulated according to the meridian theory of traditional Chinese medicine. It is a mixture of plant and animal products (1) (Table 1) and was approved in 1996 by the State Food and Drug Administration of China for treatment of angina pectoris and ischemic stroke. The contents of the capsule have been shown to have a variety of effects that are potentially of therapeutic value, such as improving endothelial cell function, lowering lipids, reducing inflammation, preventing apoptosis, and enhancing angiogenesis (1). Nevertheless, the report by Zhang et al. (14) describing the effect of Tongxinluo on plaque stability is interesting for several reasons. Briefly, the study was carried out to test the hypothesis that Tongxinluo, a Chinese traditional medicine, enhances stability of vulnerable plaques in a cholesterol-fed rabbit model of atherosclerosis. After 10 wk of feeding a diet supplemented with 1% cholesterol, five groups of animals were treated for 8 wk as follows: control group, three-dose levels of Tongxinluo, and high-dose simvastatin group. At the end of week 16, an adenovirus containing p53 was injected into the abdominal aortic plaques and plaque rupture was induced by pharmacological triggering 2 wk later. The incidence of plaque rupture in all treatment groups was significantly lower than that in the control group. The high-dose Tongxinluo and simvastatin groups had similar degrees of protection against plaque rupture. Corrected acoustic intensity and fibrous cap thickness of the aortic plaques were significantly increased, whereas plaque area, plaque burden, vulnerable index, and expression of oxidized low-density lipoprotein receptor 1, matrix metalloproteinase 1 (MMP-1), MMP-3, tissue inhibitor of MMP 1, and nuclear factorB in plaques were markedly reduced in all treatment groups compared with the control group. Tongxinluo dose-dependently lowered serum lipid levels and inhibited systemic inflammation (high-sensitive C-reactive protein). Similar to the high-dose simvastatin group, the high-dose Tongxinluo group also exhibited a reduction in low-density lipoprotein cholesterol and oxidized low-density lipoprotein, a low-expression level of systemic and local inflammatory factors and a low-plaque vulnerability index. It was concluded that Tongxinluo dose-dependently enhanced the stability of vulnerable plaques and prevented plaques from rupture. Simvastatin and Tongxinluo offered similar protection in terms of lipid-lowering, anti-inflammation, and antioxidation effects. While the findings of the study are unequivocal, there are difficulties when one attempts to reconcile pathological studies performed in the allopathic tradition with therapies derived from an entirely different medical tradition. Although digoxin and aspirin, which have been in routine use for several decades, entered the medical world as herbal remedies initially, their use today is based on a rigorous control of manufacturing practices, which have permitted researchers to undertake placebo-controlled multicenter clinical trials. In contrast, the problems that bedevil traditional remedies are the lack of standardization, the paucity of controlled clinical trials, and their failure to address mechanisms of disease. Zhang et al. (14) have addressed the first of these problems by providing information regarding the constituents of Tongxinluo. The preparation is derived from a combination of plant and animal products, and the ingredients have been identified by HPLC. It appears that the variations in the concentrations of the various compounds in it are within clinically acceptable limits. The authors elected to examine the potential role of Tongxinluo in stabilizing atherosclerotic plaques in a cholesterol-fed Address for reprint requests and other correspondence: C. T. Kappagoda, TB 172, Univ. of California Davis, Davis, CA 95616 (e-mail: ctkappagoda @ucdavis.edu). Table 1. Formulation of Tongxinluo capsule