Related Research Articles
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone sterility, and consequent increase in fracture risk. It is the most common reason for a broken bone among the elderly. Bones that commonly break include the vertebrae in the spine, the bones of the forearm, the wrist, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. After the broken bone heals, the person may have chronic pain and a decreased ability to carry out normal activities.
Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine.
Calcitonin is a 32 amino acid peptide hormone secreted by parafollicular cells (also known as C cells) of the thyroid (or endostyle) in humans and other chordates in the ultimopharyngeal body. It acts to reduce blood calcium (Ca2+), opposing the effects of parathyroid hormone (PTH).
Parathyroid hormone-related protein (PTHrP) is a proteinaceous hormone and a member of the parathyroid hormone family secreted by mesenchymal stem cells. It is occasionally secreted by cancer cells. However, it also has normal functions in bone, teeth, vascular tissues and other tissues.
Parathyroid chief cells are one of the two cell types of the parathyroid glands, along with oxyphil cells. The chief cells are much more prevalent in the parathyroid gland than the oxyphil cells. It is perceived that oxyphil cells may be derived from chief cells at puberty, as they are not present at birth like chief cells.
Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. This occurs from a disorder either within the parathyroid glands or as response to external stimuli. Symptoms of hyperparathyroidism are caused by inappropriately normal or elevated blood calcium excreted from the bones and flowing into the blood stream in response to increased production of parathyroid hormone. In healthy people, when blood calcium levels are high, parathyroid hormone levels should be low. With long-standing hyperparathyroidism, the most common symptom is kidney stones. Other symptoms may include bone pain, weakness, depression, confusion, and increased urination. Both primary and secondary may result in osteoporosis.
Teriparatide, sold under the brand name Forteo, is a form of parathyroid hormone (PTH) consisting of the first (N-terminus) 34 amino acids, which is the bioactive portion of the hormone. It is an effective anabolic agent used in the treatment of some forms of osteoporosis. Teriparatide is a recombinant human parathyroid hormone analog. It has an identical sequence to the 34 N-terminal amino acids of the 84-amino acid human parathyroid hormone.
Osteoprotegerin (OPG), also known as osteoclastogenesis inhibitory factor (OCIF) or tumour necrosis factor receptor superfamily member 11B (TNFRSF11B), is a cytokine receptor of the tumour necrosis factor (TNF) receptor superfamily encoded by the TNFRSF11B gene.
Methylprednisolone is a synthetic glucocorticoid, primarily prescribed for its anti-inflammatory and immunosuppressive effects. It is either used at low doses for chronic illnesses or used concomitantly at high doses during acute flares. Methylprednisolone and its derivatives can be administered orally or parenterally.
Primary hyperparathyroidism is a medical condition where the parathyroid gland produce excess amounts of parathyroid hormone (PTH). The symptoms of the condition relate to the resulting elevated serum calcium (hypercalcemia), which can cause digestive symptoms, kidney stones, psychiatric abnormalities, and bone disease.
Bone resorption is resorption of bone tissue, that is, the process by which osteoclasts break down the tissue in bones and release the minerals, resulting in a transfer of calcium from bone tissue to the blood.
Tertiary hyperparathyroidism is a condition involving the overproduction of the hormone, parathyroid hormone, produced by the parathyroid glands. The parathyroid glands are involved in monitoring and regulating blood calcium levels and respond by either producing or ceasing to produce parathyroid hormone. Anatomically, these glands are located in the neck, para-lateral to the thyroid gland, which does not have any influence in the production of parathyroid hormone. Parathyroid hormone is released by the parathyroid glands in response to low blood calcium circulation. Persistent low levels of circulating calcium are thought to be the catalyst in the progressive development of adenoma, in the parathyroid glands resulting in primary hyperparathyroidism. While primary hyperparathyroidism is the most common form of this condition, secondary and tertiary are thought to result due to chronic kidney disease (CKD). Estimates of CKD prevalence in the global community range from 11 to 13% which translate to a large portion of the global population at risk of developing tertiary hyperparathyroidism. Tertiary hyperparathyroidism was first described in the late 1960s and had been misdiagnosed as primary prior to this. Unlike primary hyperparathyroidism, the tertiary form presents as a progressive stage of resolved secondary hyperparathyroidism with biochemical hallmarks that include elevated calcium ion levels in the blood, hypercalcemia, along with autonomous production of parathyroid hormone and adenoma in all four parathyroid glands. Upon diagnosis treatment of tertiary hyperparathyroidism usually leads to a surgical intervention.
The calcium-sensing receptor (CaSR) is a Class C G-protein coupled receptor which senses extracellular levels of calcium ions. It is primarily expressed in the parathyroid gland, the renal tubules of the kidney and the brain. In the parathyroid gland, it controls calcium homeostasis by regulating the release of parathyroid hormone (PTH). In the kidney it has an inhibitory effect on the reabsorption of calcium, potassium, sodium, and water depending on which segment of the tubule is being activated.
Pitrakinra is a 15-kDa human recombinant protein of wild-type human interleukin-4 (IL-4). It is an IL-4 and IL-13 antagonist that has been studied in a phase IIb clinical trial for the treatment of asthma. Two point mutations on pitrakinra confer its ability to block signaling of IL-4 and interleukin-13 (IL-13) by preventing assembly of IL-4 receptor alpha (IL-4Rα) with either IL-2Rγ or IL-13Rα. Upregulation of Th2 cytokines, including IL-4 and IL-13, is thought to be critical for the allergic inflammation associated with atopic diseases such as asthma and eczema. The targets of pitrakinra action are inflammatory cells and structural cells that express IL-4Rα. The drug has been applied both as a subcutaneous injection and as an inhalation, but the latter formulation proved to be more effective.
Parathyroid hormone/parathyroid hormone-related peptide receptor, also known as parathyroid hormone 1 receptor (PTH1R), is a protein that in humans is encoded by the PTH1R gene. PTH1R functions as a receptor for parathyroid hormone (PTH) and for parathyroid hormone-related protein (PTHrP), also called parathyroid hormone-like hormone (PTHLH).
Prostaglandin E2 receptor 2, also known as EP2, is a prostaglandin receptor for prostaglandin E2 (PGE2) encoded by the human gene PTGER2: it is one of four identified EP receptors, the others being EP1, EP3, and EP4, which bind with and mediate cellular responses to PGE2 and also, but with lesser affinity and responsiveness, certain other prostanoids (see Prostaglandin receptors). EP has been implicated in various physiological and pathological responses.
An endocrine bone disease is a bone disease associated with a disorder of the endocrine system. An example is osteitis fibrosa cystica.
Abaloparatide, sold under the brand name Tymlos among others, is a parathyroid hormone-related protein (PTHrP) analog medication used to treat osteoporosis. It is an anabolic agent.
Eldecalcitol is an analog of calcitriol, the active form of vitamin D.
NPS-2143 (SB-262,470A) is a calcilytic drug which acts as an antagonist at the Calcium-sensing receptor (CaSR), and consequently stimulates release of parathyroid hormone. Calcilytic drugs have been researched as potential treatments for osteoporosis, and as the first such compound developed, NPS-2143 is still widely used in research into the CaSR receptor as well as design of newer calcilytic agents.
References
- ↑ Boron WF, Boulpaep EL (2012). Medical Physiology (2nd ed.). Elsevier Health Sciences. p. 817. ISBN 978-1-4557-1181-9.
- ↑ Nemeth EF (August 2002). "The search for calcium receptor antagonists (calcilytics)". Journal of Molecular Endocrinology. 29 (1): 15–21. doi: 10.1677/jme.0.0290015 . PMID 12200226.
- ↑ Silver J, Bushinsky D (July 2004). "Harnessing the parathyroids to create stronger bones". Current Opinion in Nephrology and Hypertension. 13 (4): 471–6. doi:10.1097/01.mnh.0000133984.47806.00. PMID 15199299. S2CID 12507535.
- ↑ Widler L (April 2011). "Calcilytics: antagonists of the calcium-sensing receptor for the treatment of osteoporosis". Future Medicinal Chemistry . 3 (5): 535–47. doi:10.4155/fmc.11.17. PMID 21526895.
- ↑ Nemeth EF, Shoback D (June 2013). "Calcimimetic and calcilytic drugs for treating bone and mineral-related disorders". Best Practice & Research. Clinical Endocrinology & Metabolism. 27 (3): 373–84. doi:10.1016/j.beem.2013.02.008. PMID 23856266.
- ↑ Kim JY, Ho H, Kim N, Liu J, Tu CL, Yenari MA, Chang W (November 2014). "Calcium-sensing receptor (CaSR) as a novel target for ischemic neuroprotection". Annals of Clinical and Translational Neurology. 1 (11): 851–66. doi:10.1002/acn3.118. PMC 4265057 . PMID 25540800.
- ↑ Aggarwal A, Prinz-Wohlgenannt M, Tennakoon S, Höbaus J, Boudot C, Mentaverri R, Brown EM, Baumgartner-Parzer S, Kállay E (September 2015). "The calcium-sensing receptor: A promising target for prevention of colorectal cancer". Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1853 (9): 2158–67. doi:10.1016/j.bbamcr.2015.02.011. PMC 4549785 . PMID 25701758.
- ↑ Dal Prà I, Chiarini A, Armato U (February 2015). "Antagonizing amyloid-β/calcium-sensing receptor signaling in human astrocytes and neurons: a key to halt Alzheimer's disease progression?". Neural Regeneration Research. 10 (2): 213–8. doi: 10.4103/1673-5374.152373 . PMC 4392667 . PMID 25883618.
- ↑ Yarova PL, Stewart AL, Sathish V, Britt RD, Thompson MA, P Lowe AP, et al. (April 2015). "Calcium-sensing receptor antagonists abrogate airway hyperresponsiveness and inflammation in allergic asthma". Science Translational Medicine. 7 (284): 284ra60. doi:10.1126/scitranslmed.aaa0282. PMC 4725057 . PMID 25904744.
- 1 2 3 Letz S, Haag C, Schulze E, Frank-Raue K, Raue F, Hofner B, Mayr B, Schöfl C (2014). "Amino alcohol- (NPS-2143) and quinazolinone-derived calcilytics (ATF936 and AXT914) differentially mitigate excessive signalling of calcium-sensing receptor mutants causing Bartter syndrome Type 5 and autosomal dominant hypocalcemia". PLOS ONE. 9 (12): e115178. Bibcode:2014PLoSO...9k5178L. doi: 10.1371/journal.pone.0115178 . PMC 4266668 . PMID 25506941.