From a general anti-cancer treatment to antioxidant or deer osteoporosis: the consequences of antler as the fastest-growing tissue.

Deer antlers are unique because they are cast and regenerate each year. They are the fastest-growing structure, reaching an astonishing growth rate of up to 2.75 cm/day in length and more than 20 cm2/day of skin. Surprisingly, no study so far has assessed the metabolic rate of the antler. High metabolic rate needs highly efficient (or large) mitochondria, and it involves a high creation or reactive oxygen species (ROS), origin of oxidative stress. The speed of creation of ROS and the oxidative stress are inversely related to ageing and many diseases such as cancer or age-related diseases. However, antler must have the most efficient anti-oxidant system, as it rarely shows any departure from a perfect growth. This paper examines recent studies showing surprising applications in medicine of growing-antler extracts, or the information regarding its physiology. A recent study (Wang et al. (2019) , Science 364, eaav6335) has shown that antlers have evolved a speed of growth faster than cancer, based on high expression of proto-oncogenes. As a result, deer has evolved tumour-suppression genes to control the high risk of developing cancer. This may explain why several studies have found in vitro and in vivo anti-cancer effects of deer velvet-antler extract in human tumours, such as cell cultures and animal models of cancers such as brain cancer (glioblastoma), prostate cancer, and others. We will also discuss findings in the study of the cyclic osteoporosis of the deer, with unexpected similarities in their proteomics and gene expression with that of the human pathological osteoporosis. Last, we will examine potential applications based on having the highest metabolic rate. If the future studies establish the antler as the tissue having the fastest metabolism and the best antioxidant system, this may have implications for understanding how to fight oxidative stress, which, in turn, will have direct implications for aging and age-related diseases (and others, from cancer to osteoporosis and Alzheimer's for example). It may also show that velvet-antler extract is a general anti-cancer compound, and this may show the path to find an anti-cancer medicine that has no secondary toxic effects in healthy cells. Antler is the only mammal structure regenerating each year, and it is the fastest-growing tissue (much faster-growing than cancer). For this reason, several interesting medical applications are reviewed in this paper, such as anti-cancer activity of growing-antler extract. Studying growing antler may help develop powerful and general anti-cancer treatments without secondary effects, and the high metabolic rate and antioxidant system of the antler may also have other potential medical applications, such as delaying aging- or fight-associated diseases. [ABSTRACT FROM AUTHOR]