View clinical trials related to Hypoparathyroidism.
Filter by:Whereas much information is known about the properties of bone in primary hyperparathyroidism, a disorder of parathyroid hormone (PTH) excess, virtually nothing is known about the skeleton in hypoparathyroidism, a disorder in which PTH is absent. The purpose of this research project is to test the hypothesis that the skeleton in hypoparathyroidism is abnormal in its metabolic, densitometric, geometric, biomechanical and microarchitectural features. We will also test the hypothesis that the skeleton is dependent upon PTH for normal structure and function. Using non-invasive approaches as well as direct analysis of bone itself, the human hypoparathyroid skeleton will be thoroughly characterized. With each patient serving as his/her own control, we will determine how, to what extent, and in what ways the administration of PTH restores skeletal dynamics and structure to the hypoparathyroid skeleton. In this way, we will identify those structural and dynamic elements of the skeleton that are influenced by or dependent upon PTH. Methods to be utilized include dual energy X-ray absorptiometry, quantitative central and peripheral computed tomography, geometry and size quantification, histomorphometry by standard and microCT methods, finite element analysis, biochemical bone markers, quantitative back scattered electron imaging, and Fourier Transform Infrared Spectroscopy. This research project will extend our knowledge of the skeletal effects of PTH to its deficient range and thus complete our understanding of PTH action on bone gained by our many years of studying PTH overexpression in primary hyperparathyroidism. This investigation may also provide insight into the means by which PTH helps to restore the skeleton when it is used to treat osteoporosis.
Hypoparathyroidism is a rare condition associated with a low level of parathyroid hormone (PTH) in the blood. Hypoparathyroidism can be genetic and show up in childhood, or it can occur later in life. If it occurs later, it is usually due to damage or removal of the parathyroid glands during neck surgery. PTH helps control the amount of calcium in blood, kidneys, and bones. Low levels of calcium in the blood can cause a person to feel sick. It can cause cramping or tingling in the hands, feet, or other parts of the body. A very low blood calcium can cause fainting or seizures. The standard treatment for hypoparathyroidism is a form of vitamin D (calcitriol) and calcium supplements. Keeping normal blood levels of calcium can be difficult. Sometimes there is too much calcium in the urine even if the calcium levels in the blood are low. High calcium in the kidneys and urine can cause problems such as calcium deposits in the kidney (nephrocalcinosis) or kidney stones. High levels of calcium in the kidney may keep the kidney from functioning normally. Treatment with PTH will replace the hormone you are missing. Your disease may be better controlled on PTH than on calcium and calcitriol. Researchers at the NIH have conducted prior studies to establish synthetic human parathyroid hormone 1-34 (HPTH) as a treatment for hypoparathyroidism. Other studies have shown that PTH may improve calcium levels in blood and urine. The primary purpose of this research study is to evaluate the effects of synthetic human parathyroid hormone 1-34 (HPTH) replacement therapy on bone in adults and teenagers with hypoparathyroidism. The study takes 5 (Omega) years to complete and requires 12 inpatient visits to the National Institutes of Health Clinical Center in Bethesda, MD. The first visit will help the study team decide whether you are eligible. This visit will last 2 to 3 days. After taking calcium and calcitriol for 1 - 7 months you will return to the NIH Clinical Center for the baseline visit. The baseline visit is the visit that you will start your PTH; you will also undergo a bone biopsy during the visit. The baseline visit may last 7 to 10 days. You will then take PTH twice a day for 5 years. You will be asked to return to the NIH clinical center every 6 months for 10 follow-up visits. During one of the follow-up visits, you will have a second bone biopsy taken from the other hip. That second biopsy will be done after 1 year, 2 years, or 4 years of taking PTH; the researchers will assign the timing of the second biopsy randomly. You will be asked to go to your local laboratory for blood and urine tests between each follow up visit. At first the blood tests will occur at least once a week. Later, you will need to go to your local laboratory for blood tests at least once a month and urine tests once every 3 months. The local laboratory visits and follow-up visits at the NIH Clinical Center will help the study team determine whether the HPTH treatment is controlling your hypoparathyroidism.
This study will explore the regulation of fibroblast growth factor-23 (FGF-23). It is a hormone recently identified as a regulator of the blood levels of phosphorus and vitamin D, both of which are essential for overall health and especially important for bone health. The parathyroid hormone (PTH) regulates phosphorus and calcium, but people with hypoparathyroidism or pseudohypoparathyroidism do not have sufficient PTH action. There are genetic diseases that influence FGF-23, causing abnormal metabolism of phosphorus and vitamin D, thus affecting the bones. Also, there are rare tumors that may cause overproduction of FGF-23 causing debilitating bone disease. Patients ages 18 and older who have low PTH levels, or are resistant to PTH action, and take calcitriol and calcium supplements, who are not pregnant, and who do not have kidney disorders may be eligible for this study. During the 4-day study, patients will be provided with a controlled diet that has a lower than usual phosphorus content. On day 1, patients will be admitted to the NIH Clinic Center and undergo blood and urine tests to measure calcium, phosphorus, vitamin D, and FGF-23. They will continue with their regular medicine for hypoparathyroidism. On that day and throughout the study, patients will fast from 10:00 p.m. to 8:00 a.m. the following day. On day 2, patients will continue fasting until 4:00 p.m. A tube will be placed in the vein of each arm: one for drawing blood and the other for infusing calcium. Just one intravenous (IV) line will be used on the other days. Patients will receive calcium chloride for 8 hours, at a dose carefully monitored by a machine. The purpose is to bring the blood calcium level to the high normal range or just above. Blood and urine samples will be collected periodically, to check for effects of calcium chloride on FGF-23 and PTH. On days 3 and 4, patients will not take calcitriol and calcium but will receive injections of PTH, under the skin, two times each day. On day 3, blood and urine samples will be again be collected for analysis. On day 4, patients will receive one dose of calcitriol by IV. The total amount of blood drawn during this study will be about 5 ounces.
OBJECTIVES: I. Identify latent hypoparathyroidism in normocalcemic adult survivors with repaired conotruncal cardiac defects, by evaluating parathyroid gland secretory function after induced hypocalcemia. II. Determine the relationship of parathyroid hormone secretion to microdeletions in the same region of chromosome 22q11 as found in patients with DiGeorge anomaly.
This study has been important in establishing synthetic human parathyroid hormone 1-34 (PTH) as a beneficial treatment for hypoparathyroidism, superior to conventional therapy with calcium and calcitriol. Providing synthetic human parathyroid hormone 1-34 (PTH) to patients who are unresponsive to conventional therapy has enabled severe cases of hypoparathyroidism to be managed effectively with the investigational drug, PTH. The primary goals of this study are to (1) provide long-term PTH therapy to patients who do not respond to conventional therapy; (2) understand the long-term effect of therapeutic PTH replacement on kidney function and bone mineral density; (3) study and track linear growth and bone accrual in children with hypoparathyroidism. (4) determine if subjects reach a normal level of peak bone mass and if the timing of this is comparable to normal age-matched healthy controls.