A phase I dose-escalation study to evaluate tolerability in a Western population to T89, a modern cardiovascular herbal medicine.

T89 (Dantonic) is a modern herbal medicine currently used in Chinese hospitals for the management of ischemic heart disease. This dose-escalation clinical trial aims to assess tolerability of Western people to T89. Healthy Australian adults of non-Asian background orally took a single dosage of 6, 8, 10, 12, 13, 14, 15, or 16 T89 capsules (6 people for each dose) and were assessed with respect to symptoms and physical signs, electrocardiogram, hematology, plasma biochemistry, and urinalysis. Secondary objectives were to determine the dose-limiting toxicity and maximum-tolerated dose. It found that a single dose of T89 up to 16 capsules was not associated with significant adverse events or abnormalities in clinical laboratory tests and electrocardiogram parameters, except minor symptoms reported included mild and transient dizziness, stomach discomfort, diarrhea, and involuntary muscular contraction. The incident rate of these symptoms was generally low (1/30, 3.3%) but increased (7/18, 38.9%) in higher dose (≥14 capsules) groups. No defined dose-limiting toxicity events occurred; so the study could not define the maximum-tolerated dose. In conclusion, a single dose of T89 up to 13 capsules, 4 times of a regular therapeutic dosage, is generally safe and tolerated by individuals of non-Asian background.

Physiological effects of androgens on human vascular endothelial and smooth muscle cells in culture.

Androgenic hormones are associated with atherosclerotic cardiovascular disease, although the underlying cellular and molecular mechanisms remain unclear. This study examines the impact of androgens on the physiology of human vascular endothelial cells (EC) and smooth muscle cells (SMC) in culture. Cells were incubated with testosterone, dihydrotestosterone (DHT) or dehydroepiandrosterone (DHEA) at various physiological concentrations (5-50 nM) in the present or absence of an androgen receptor (AR) blocker flutamide (100 nM). Cell growth and death, DNA and collagen synthesis, and gene protein expression were assessed. It was shown that: (1) DHEA protected EC from superoxide injury via AR-independent mechanisms; (2) testosterone induced DNA synthesis and growth in EC via an AR-independent manner with activation of ERK1/2 activity; (3) DHT inhibited DNA synthesis and growth in EC in an AR-dependent manner; (4) testosterone and DHT enhanced ERK1/2 activation and proliferation in SMC via AR-independent and -dependent pathways, respectively; and (5) these androgens did not significantly affect collagen synthesis in SMC. We conclude that androgens possess multiple effects on vascular cells via either AR-dependent or -independent mechanisms. Testosterone and DHEA may be "beneficial" in preventing atherosclerosis by improving EC growth and survival; in contrast, stimulation of VSMC proliferation by testosterone and DHT is potentially "harmful". The relationship of these in vitro effects by androgens to in vivo vascular function and atherogenesis needs to be further clarified.