On page 50 paragraph two, Moalem mentions a disease called rickets that is directly correlated to vitamin D deficiency. Vitamin D is responsible for bone growth and maintenance because it regulates the calcium and phosphorus levels in the human body. It has also been discovered that vitamin D is required for the heart, immune system, the nervous system, and the clotting process to function correctly. The regulation of these systems in the body through vitamin D directly relates to Big Idea 4 (Biological systems interact, and these systems and their interactions possess complex properties.)
Choose one of the four systems/processes above (heart, immune system, nervous system, or clotting process) and explain how vitamin D contributes to its function. Explain how the calcium and phosphorus levels that are kept up by vitamin D affect the process or system. Also, if vitamin D is not present, what potential consequences could ensue? Malone also mentions that a deficiency in vitamin D not only causes rickets, but it has been associated with osteoporosis, heart disease, diabetes, arthritis, psoriasis, and mental illness. Select one of these diseases and research how low levels of vitamin D could affect the human body and lead to its development. ( Hint: how could insufficient levels of calcium and phosphorus lead to the disease?)
(Posted by Vivian To, vivto4@students.d125.org)
According to Professor Geisler in the article "Vitamin D Crucial to Activating Immune Defenses" from ScienceDaily, "when a T cell is exposed to a foreign pathogen, it extends a signaling device or 'antenna' known as a vitamin D receptor, with which it searches for vitamin D" in our blood (qtd in Vitamin D...). As we learned in class, our T cells are never activated into neither killer T cells nor helper T cells and can't kill infected cells or activate B cells to produce antibodies, respectively. So without Vitamin D, the humoral and cell-mediated responses are never activated, so macrophages are the only defense left to attack antigens. Calcium levels that are regulated by Vitamin D are also necessary in activating the inflammatory response. According to the article "Calcium Is Initial Trigger in Our Immune Response to Healing" from ScienceDaily, there is an initial "flash of calcium signal [which] goes on to activate an enzyme known as DUOX that synthesises hydrogen peroxide, which, in turn, attracts the first white blood cells to the wound." These white blood cells kill the invading microbes at the wound. So, without Vitamin D to regulate Calcium levels, the lack of calcium will cause the inflammatory response to not be activated, allowing microbes to enter into our body.
ReplyDeleteMoalem explains how Vitamin D is necessary for the "maintenance of healthy bones in adults" (Moalem 50). According to PubMed Health, "Osteoporosis is a disease in which bones become fragile and more likely to fracture. Usually the bone loses density, which measures the amount of calcium and minerals in the bone." So, Vitamin D prevents osteoporosis by regulating calcium levels that are used to strengthen bones and increase bone density. According to the article "Phosphates and Osteoporosis" by Gail Morris from Livestrong.com, high levels of phosphorus "reduces the formation of Vitamin D in the kidneys" and also causes kidney failure. When kidneys can't function properly and remove phosphorus from our blood, our bones begin to lose calcium. So, the regulation of phosphorus by Vitamin D is necessary to prevent kidney damage and calcium deficiency in our bones.
This all relates to Big Idea 4 because Vitamin D interacts with phosphorus and calcium by regulating them. Phosphorus in turn affects the kidneys and the urinary system. Calcium affects our bones and activates the inflammatory response. Vitamin D also interacts with the immune system by directly activating T cells. The T cells then interact with B cells and killer T cells to help fight off an invading antigen.
Vitamin D Crucial to Activating Immune Defenses:
http://www.sciencedaily.com/releases/2010/03/100307215534.htm
Calcium Is Initial Trigger in Our Immune Response to Healing:
http://www.sciencedaily.com/releases/2013/02/130214111608.htm
PubMed Health:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001400/
Phosphate and Osteoporosis:
http://www.livestrong.com/article/443982-phosphate-osteoporosis/
(Name: Will Han email: wihan4@students.d125.org)
According to “Vitamin D May Prevent Clogged Arteries in Diabetics” from Science Daily, Vitamin D works with immune cells called macrophages to keep arteries clear or to clog them. The macrophages begin their existence as a type of leukocytes called monocytes that circulate in the bloodstream. When monocytes encounter inflammation, they are transformed into macrophages that don’t circulate. (http://www.sciencedaily.com/releases/2012/11/121113134222.htm) To keep the heart functioning, arteries have to be clear for blood to move smoothly and not get clogged up in blood vessels. According to the scientific journal “The control of calcium and phosphorus metabolism by the vitamin D endocrine system”, hydroxylation on the 25-position in the liver followed by 1 alpha-hydroxylation in the kidney produces the vitamin D hormone, 1 alpha, 25-(OH)2D3. This vitamin D hormone functions in the intestine, bone, and kidney to stimulate transport of calcium and phosphorus into the extracellular fluid compartment on demand. The production of the vitamin D hormone is feedback regulated by calcium and phosphorus levels of the plasma.(http://www.ncbi.nlm.nih.gov/pubmed/7015957) According to the science daily study, patients with insufficient vitamin D have immune cells that bind to blood vessels near the heart, then trap cholesterol to block those blood vessels. Macrophage cells were more likely to adhere to the walls of blood vessels to trigger cells to get loaded with cholesterol, eventually causing the vessels to stiffen and block blood flow in many people with low vitamin D levels..That causes heart problems and can lead to heart disease.
ReplyDeleteAs said by Moalem on page 50, Vitamin D is responsible for bone growth and maintenance in the body. From a study in Science Daily, it’s possible that vitamin D deficiency increases the risk of heart disease. Vitamin D deficiency has traditionally been linked with poor bone health like with diseases like Osteoporosis as Will mentioned. While that can cause problems with how strong bones are, I think that increased chance of heart disease is also as deadly. Vitamin D deficiency may increase blood pressure, and it’s known that high blood pressure increases the risk of heart attack. (http://www.sciencedaily.com/releases/2012/09/120924102504.htm) The main problem of heart disease is a shortened life spam for millions of people in the world. While low levels of Vitamin D cause poor health in general, the main problem is that it ends life so quickly in many people it affects. With more cholesterol clogging blood vessels, the heart can’t function properly. That is how low vitamin D levels can cause problems involving heart disease.
This response relates to Big Idea 4(Biological systems interact, and these systems and their interactions possess complex properties. ) because Vitamin D interacts with phosphorous and calcium levels and regulates them. Vitamin D affects the heart by making macrophages clean off arteries so they don’t clog with cholesterol to cause heart problems. The efficiency between cells also keeps calcium and phosphorous levels high enough and it improves the efficiency of the body overall. The feedback with the levels of calcium and phosphorous also make it so there is phosphorous to help the kidney system and enough vitamin D to make sure blood vessels don’t clog up to heart to keep the heart functioning.
(Eric Huang, ehuang4@students.d125.org)