Oxidative stress, free radicals and bone remodeling

Abstract

Reactive oxygen species (ROS) are widely considered to be a causal factor in aging and in a number of pathological conditions, such as atherosclerosis, carcinogenesis and infarction. Their role in bone metabolism is dual, considering their effects under physiological or pathological conditions. Under physiological conditions, the production of ROS by osteoclasts helps accelerate destruction of calcified tissue, thus assisting in bone remodeling. In pathological conditions, when a bone fractures, e.g., radical generation is remarkably high. However, though the increases in osteoclastic activity and ROS production are linked in many skeletal pathologies, it remains to be clarified whether increased ROS production overwhelms antioxidant defenses, leaving the individual open to hyperoxidant stress.

Effects of Robusta coffee (Coffea canephora) brewing on levels of RANKL and TGF- β1 in orthodontic tooth movement

“…In other words, antioxidant activity is important in stimulating osteoblastic activity through specific receptors to support bone growth. 25 On day 22, the results of the research showed that the levels of TGF-β1 at the pressure and tension sites after the administration of coffee brew significantly decreased compared to those on day 15. It is due to the reduced orthodontic pressure, so bone formation also decreased.…”

The increased number of osteoblasts and capillaries in orthodontic tooth movement post-administration of Robusta coffee extract

“…This scenario could be caused by the antioxidant effects of the chlorogenic acid and caffeic acid contained in the coffee extract not only increasing osteoblast differentiation, but also promoting osteoblast activity. 22,28 Consequently, both VEGF expression and the number of capillaries increase.…”

“…19 Robusta coffee contains chlorogenic acid, phenylalanines formed during the roasting process, 20 and caffeic acid, which produce antioxidant effects in reducing oxidative stress in osteoblasts 21 and stimulate osteoblast activity. 22 Moreover, clorogenic and caffeic acids in Robusta coffee produce antioxidant effects in enhancing angiogenesis through increased VEGF. 23 Results of research on mice even showed that the administration of Robusta coffee at a dose of 20 mg/100 g BM (equivalent to one cup of coffee in humans) increased the number of osteoclasts on the 15th day.…”

Oxidative stress in bone remodeling: role of antioxidants

“…Healthy bone is tightly regulated and maintained in order to prevent significant alterations in bone mass or mechanical strength after each remodeling cycle (29). Indeed, oxidative stress alters bone remodeling process causing an unbalance between osteoclast and osteoblast activity, this can lead to metabolic bone diseases and contribute to the pathogenesis of skeletal system disorders including osteoporosis characterized by low bone mineral density and decrease in bone mass, which makes the bone weak and more prone to fracture (18,(33)(34)(35)(36). Recent evidences in a limited number of clinical studies have shown that ROS and/or antioxidant systems can be involved in the pathogenesis of bone loss (36)(37)(38)(39).…”