A Review - Vitamin D and Calcium in Sarcoidosis
Trevor G Marshall, PhD, 5 July 2003
The active hormone of Vitamin D (1,25-dihydroxyvitamin-D)(1,25-D) performs a vital function in immune diseases, including Sarcoidosis. It causes hematopoetic-stem-cells to differentiate (grow) into monocytes, the basic White Blood Cell (leukocyte), and then it causes these to differentiate (grow) into the macrophages and giant cells characteristic of sarcoid granuloma[1,2]. Without this hormone there would be no formation of granuloma. The hormone is also responsible for maintaining proper operation of the ParaThyroid, Muscle, Pancreas, Bone, Intestine, Kidneys, Heart and the Brain .
(Image: Unversity of California, Riverside)
In the past it had been thought that this hormone was primarily responsible for maintaining the Calcium homeostasis (balance) in the body. But, now that the controlling Genes have been sequenced, Molecular Medicine has found that this is just not true. In fact, Hypercalciuria, the excess excretion of calcium in the urine, is actually a function of the PTH (ParaThyroid Hormone) and of the calcium-sensing receptor (CASR) in the kidney tubules[4,5]. The 1,25-D hormone affects these processes, but is not primarily responsible for hypercalciuria or hypercalcemia.
Sarcoidosis patients manufacture the 1,25-D hormone within the inflammatory granuloma, under the influence of Angiotensin II and Interferon-gamma . While most Sarcoidosis patients possess high levels of 1,25-D in their blood[7,6], only a small fraction of them ever exhibit Hypercalcemia.
Physicians have been slow to assimilate the discoveries coming from Molecular Medicine.They often associate the 1,25-D hormone as solely related to calcium balance. Yet a search of the National Library of Medicine for 'VDR' (the Vitamin D Receptor molecule) yields 1410 studies, only half of which even mention the word "calcium".
High levels of the 1,25-D hormone affect muscle function, especially the cardiac muscle[8,9,10]. It is thus critical for a Clinician to measure this hormone and keep its level under control. One way of achieving control is to totally eliminate all sources of dietary Vitamin D intake from food, and all sources of exposure to bright light, until the Sarcodiosis patient is no longer producing the 1,25-D hormone beyond the Merck maximum (45pg/ml).
At levels above about 42 pg/ml, the 1,25-D (generated by the sarcoid inflammation) begins to stimulate bone osteoclasts, causing bone to be resorbed (dissolved) back into the bloodstream. Not only does this lead to osteporosis, but also to calcium being deposited into soft tissue of the body, including the lungs, breasts, and the kidneys (where it forms kidney stones).
Some clinicians still administer Calcium and Vitamin D supplementation to their sarcoidosis patients in the vain hope that this supplementation will somehow prevent, or reverse, osteoporosis resulting from the sarcoid inflammation itself, or osteoporosis resulting from the use of corticosteroids. But the calcium metabolism of sarcodiosis patients is not the same as that of healthy individuals[13,16]. There is no clinical evidence that supplementation has any beneficial effect on sarcoid osteoporosis[14,15], indeed, since the Vitamin D supplement often causes the 1,25-D hormone to rise to extremely high levels, supplementation can actually increase bone resorption, increasing the rate of bone-weakening.
Corticosteroids reduce the formation of new bone by decreasing Cbfal, TGFbetaR1, BMP-2, IGF and the Bcl-2/BAX ratio, while increasing PPARgamma2. None of these effects has anything to do with the Calcium metabolism. Calcium supplements will have no effect on any of the steroids' osteoporotic processes. Not only are there no conclusive studies to validate any supposed benefits of Vitamin D and Calcium supplementation in steroid-treated sarcoidosis[eg 14], the Molecular Medicine explains why such supplementation is futile, and will most probably make the osteoporosis worse.
Patients who have controlled their level of 1,25-D have discovered that the most annoying neural symptoms of Sarcoidosis have also disappeared: fatigue, irritability, panic, depression, and sleep disturbance. Vitamin D supplements typically make these symptoms worse.
Clearly the gap between Molecular Medicine and Clinical Practice has to be narrowed if Clinicians are ever to understand the cause of Sarcoidosis, and be able to cure it. Knowledgable physicians and patients are routinely inducing remission. But many sarcoid patients trust and rely upon Sarcoid Specialists for their care. It is encumbent upon those specialists to expend the energies needed to comprehend and apply the most up-to-date information about how the human body actually works... The cure for Sarcoidosis is within our reach. Carpe Diem!
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