Vitamin K is commonly thought of pertaining to blood coagulation, but there has been recent research indicating its vital role in bone growth and maintenance. Bone is composed of ratios of cortical and trabecular tissue with varying amounts of collagen and hydroxyapatite, depending on the bone itself. The matrix of hydroxyapatite is a crystalline lattice that provides rigidity to the bone structure. Through a mediated process and various molecules Vitamin K initiates the attraction of Ca2+ and incorporation into the hydroxyapatite crystalline lattice. Of course with limited Vitamin K leads to a less developed bone matrix, and therefore lower bone mineral density, ultimately.
More specifically:
Osteoclasts are involved in the degredation of bone tissue which is greatly important to the process of bone modeling and remodeling. On the flip side, high levels of osteoclastic activity can result in the demineralization of our bone tissue and ultimately decrease our bone mineral density (BMD). Vitamin K plays an important role in regulating osteoclastic activity by controlling the synthesis and programmed death (apoptosis) of osteclasts.
In addition to the regulation of bone resorption, vitamin K plays a significant role in bone formation and maintenance as well. Osteocalcin is a very important bone protein secreted by osteoblasts. This protein must be carboxylated in order to be utilized and implemented in our bone structure and aid in building our bone mineral density. Vitamin K is involved in a coupled reaction allowing the enzyme carboxylase to mediate the carboxylation of osteocalcin. Therefore, without the presence of Vitamin K bone remodeling does not occur and negatively affects our BMD.
Coupled reaction:
* Warafrin is an anticoagulant drug that blocks the reduction of Vitamin K. What we are intersted in is the entire coupled reaction that allows carboxylation of the protein.
Bugel S. Vitamin K and Bone Health. 2003. http://www.ncbi.nlm.nih.gov/pubmed/15018483
wow vitamin k programs the death of osteoclasts?! that's crazy. it's interesting that this vitamin works the angle from both helping the osteoblasts do their job and decreases the osteoclast production, vitamin k working for the bone health
ReplyDeleteI agree that is so interesting! It's amazing how little information, relatively speaking, there is about vitamin K and bone tissue. It really does present very critical roles in maintaing tissue through remodeling.
ReplyDeleteThe concept that Vitamin K plays an important role in regulating osteoclastic activity by controlling the synthesis and programmed death of osteclasts, is really new to me. Before checking out you blog i had no idea what Vitamin K was even needed for in our bodies. However, to hear that it is important in the regulation osteoclast activity is so essential to the bone. Also i was curious if you found in your research any correlation between higher intake of vitamin K in people that suffer a chronic bone disease like osteoporosis? I only ask because most bone disease are a result of over active osteoclast, which cause the break down of the bone before osteoblast can form new bone.
ReplyDeleteThat's a great question, Ashley! I have not come across any research presenting information on that aspect specifically. Form what I've gathered the osteclastic activity is managed homeostatically through synthesis and apoptosis (programmed cell death). The physiologocal mechanisms we have control for excess osteoclastic activity and therefore keep from essentially decreasing BMD.
ReplyDeleteI have found research relating vitamin k with a reduction in fractures, mainly of the hip. Vitamin K doesn't directly influence osteoporosis, but can help to increase remodeling through osteoclast and osteoblast functioning.