Calcium Homeostasis in Acromegaly: Effect of Surgical/Medical Treatment and Comparison With Nonfunctioning Pituitary Tumors

Acromegaly Clinical Trial

Official title:

Calcium Homeostasis in Acromegaly: Effect of Surgical/Medical Treatment and Comparison With Nonfunctioning Pituitary Tumors.

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01568359
• Other study ID #: IRB00046786
• Status: Completed
• Phase: N/A
• First received: March 29, 2012
• Last updated: December 4, 2014
• Start date: December 2011
• Est. completion date: August 2014

Study information

• Verified date: December 2014
• Source: Emory University
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Observational

Clinical Trial Summary

The purpose of the study is to evaluate the Calcium homeostasis in adult patients with uncontrolled acromegaly. The measurements will be repeated 3-6 months after the treatment of acromegaly (surgical or medical). The control group consists of patients with nonfunctioning pituitary tumors who will undergo surgical removal.

Description:

Calcitriol is the active form of vitamin D. Parathyroid hormone (PTH) is secreted by the parathyroid glands in the neck. Both these chemicals are responsible for keeping the levels of calcium and phosphorous normal and also play a role in bone health. They can be measured in the blood. In some disorders, PTH or calcitriol levels are elevated, which results in increased calcium absorption from the gut, increased calcium in the bloodstream, and increased calcium excretion in the urine. Increased calcium in the urine can lead to the development of kidney stones. Increased calcium in the bloodstream can have adverse effects on the heart, gut, kidneys, and bones.

Acromegaly is a condition where a pituitary tumor secretes excessive amounts of growth hormone. Patients with acromegaly have been found to have a higher prevalence of kidney stones, urinary calcium, and serum calcium when compared to normal adults. The reason for this is unknown but a suggested mechanism is that growth hormone stimulates the production of calcitriol or PTH. If this is true, then treatment of acromegaly resulting in lower growth hormone levels should also result in lower blood and urine calcium levels. The investigators want to see if patients with acromegaly have high calcitriol, and vitamin D binding protein, or PTH levels and see if they change after treatment of the condition. The investigators also want to assess the amount of calcium in the urine, before and after treatment.

Patients with acromegaly may have disorders of bone health. The reason for this is unknown but a suggested mechanism is that growth hormone affects bone remodeling. The investigators want to see if patients with acromegaly have abnormal bone markers, specifically PINP, CTX, and TRAP, and to see if they change after treatment of the condition.

In order to see if the results are specific to patients with acromegaly, the investigators also want to check these levels in patients who do not have acromegaly, but have a "nonfunctioning" pituitary tumor. A nonfunctioning pituitary tumor is one that does not secrete excessive hormones in the bloodstream.

The specific aims of this study are:

1. To describe baseline calcitriol/PTH status in patients with uncontrolled acromegaly.

2. To assess the change in calcitriol/PTH levels after treatment with acromegaly (surgical or medical).

3. To evaluate the calcium and calcitriol/PTH levels in patients with acromegaly compared to patients with nonfunctioning pituitary adenomas.

This is a voluntary study. Adult patients with a diagnosis of acromegaly or a clinically nonfunctioning pituitary tumor receiving treatment at the Emory University Pituitary center will be given the opportunity to enroll in the study. Those that agree to participate will need to give written informed consent. Approximately 3 tablespoons (44ml) of blood will be drawn at enrollment for testing of vitamin D status and parathyroid hormone. If patients are already undergoing a blood draw for standard laboratory tests, then the volume of 44ml of blood will be obtained at the same time in order to avoid an additional needle stick. In addition, a 24-hour urine collection will be obtained to assess the amount of calcium present in the urine. Please note that medical or surgical therapy for your pituitary condition is determined by your endocrinologist and/or neurosurgeon and not part of the research study.

Within 6 months after treatment for pituitary treatment is initiated, when patients return to Emory University pituitary clinic for routine visit, laboratory data (vitamin D and parathyroid hormone) and repeat urine studies (24 hour urine collection) will be collected.

The confidentiality will be respected in all encounters. No personal identifiers are disclosed in any publications. Hard copy data will be kept securely in a locked office building with limited access and electronic data will always be password protected with access available to study personnel only. If abnormal results are discovered as part of testing done for this study, those results will be released to the patient's primary physician. All patients will be undergoing standard therapy for their pituitary disorder.

Results of this study may have important implications for future studies that are designed to evaluate the mechanism of how growth hormone may increase calcitriol levels.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 49
• Est. completion date: August 2014
• Est. primary completion date: August 2014
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Patients diagnosed with acromegaly or a nonfunctioning pituitary who will receive treatment for the pituitary condition.

• Study subjects must agree to participate in this study and provide written consent.

• Site- Emory Clinic/Emory University hospital.

• Stage of Disease: Patients with active acromegaly that is either newly diagnosed or uncontrolled on current therapy (as shown by GH/IGF-1 levels). Patients with nonfunctioning pituitary adenoma in whom surgical intervention planned based on current guidelines will serve as a control group.

• Age: Study subjects must be over 18 years of age.

Exclusion Criteria:

• Age < 18 years old

• Prior other diseases: Patients chronic renal disease stage 3 or worse (estimated GFR > 60).

Study Design

Observational Model: Case Control, Time Perspective: Prospective

Related Conditions & MeSH terms

• Acromegaly
• Nonfunctioning Pituitary Tumor
• Pituitary Diseases
• Pituitary Neoplasms

Locations

Country	Name	City	State
United States	Emory Clinic	Atlanta	Georgia
United States	Emory University Hospital	Atlanta	Georgia

Sponsors (1)

Lead Sponsor	Collaborator
Emory University

Country where clinical trial is conducted

United States, 

References & Publications (16)

Ajibade DV, Dhawan P, Fechner AJ, Meyer MB, Pike JW, Christakos S. Evidence for a role of prolactin in calcium homeostasis: regulation of intestinal transient receptor potential vanilloid type 6, intestinal calcium absorption, and the 25-hydroxyvitamin D(3) 1alpha hydroxylase gene by prolactin. Endocrinology. 2010 Jul;151(7):2974-84. doi: 10.1210/en.2010-0033. Epub 2010 May 12. — View Citation

Brown DJ, Spanos E, MacIntyre I. Role of pituitary hormones in regulating renal vitamin D metabolism in man. Br Med J. 1980 Feb 2;280(6210):277-8. — View Citation

Chanson P, Salenave S, Kamenicky P, Cazabat L, Young J. Pituitary tumours: acromegaly. Best Pract Res Clin Endocrinol Metab. 2009 Oct;23(5):555-74. doi: 10.1016/j.beem.2009.05.010. Review. — View Citation

Charoenphandhu N, Wongdee K, Krishnamra N. Is prolactin the cardinal calciotropic maternal hormone? Trends Endocrinol Metab. 2010 Jul;21(7):395-401. doi: 10.1016/j.tem.2010.02.002. Epub 2010 Mar 20. — View Citation

Cook DM, Ezzat S, Katznelson L, Kleinberg DL, Laws ER Jr, Nippoldt TB, Swearingen B, Vance ML; AACE Acromegaly Guidelines Task Force. AACE Medical Guidelines for Clinical Practice for the diagnosis and treatment of acromegaly. Endocr Pract. 2004 May-Jun;10(3):213-25. Erratum in: Endocr Pract. 2005 Mar-Apr;11(2):144. Endocr Pract. 2008 Sep;14(6):802-3. Cook, David M [added]; Ezzat, Shereen [added]; Katznelson, Laurence [added]; Kleinberg, David L [added]; Laws, Edward R Jr [added]; Nippoldt, Todd B [added]; Swearingen, Brooke [added]; Vance, Mary Lee [added]. — View Citation

Ezzat S, Melmed S, Endres D, Eyre DR, Singer FR. Biochemical assessment of bone formation and resorption in acromegaly. J Clin Endocrinol Metab. 1993 Jun;76(6):1452-7. — View Citation

Halse J, Haugen HN. Calcium and phosphate metabolism in acromegaly. Acta Endocrinol (Copenh). 1980 Aug;94(4):459-67. — View Citation

Hennessey JV, Jackson IM. Clinical features and differential diagnosis of pituitary tumours with emphasis on acromegaly. Baillieres Clin Endocrinol Metab. 1995 Apr;9(2):271-314. Review. — View Citation

Lancer SR, Bowser EN, Hargis GK. The effect of growth hormone on parathyroid function in rats. Endocrinology. 1976 May;98(5):1289-93. — View Citation

Lund B, Eskildsen PC, Lund B, Norman AW, Sørensen OH. Calcium and vitamin D metabolism in acromegaly. Acta Endocrinol (Copenh). 1981 Apr;96(4):444-50. — View Citation

Nadarajah A, Hartog M, Redfern B, Thalassinos N, Wright AD, Joplin GF, Fraser TR. Calcium metabolism in acromegaly. Br Med J. 1968 Dec 28;4(5634):797-801. — View Citation

Parkinson C, Kassem M, Heickendorff L, Flyvbjerg A, Trainer PJ. Pegvisomant-induced serum insulin-like growth factor-I normalization in patients with acromegaly returns elevated markers of bone turnover to normal. J Clin Endocrinol Metab. 2003 Dec;88(12):5650-5. — View Citation

Sigurdsson G, Nunziata V, Reiner M, Nadarajah A, Joplin GF. Calcium absorption and excretion in the gut in acromegaly. Clin Endocrinol (Oxf). 1973 Jul;2(3):187-92. — View Citation

Takamoto S, Tsuchiya H, Onishi T, Morimoto S, Imanaka S, Mori S, Seino Y, Uozumi T, Kumahara Y. Changes in calcium homeostasis in acromegaly treated by pituitary adenomectomy. J Clin Endocrinol Metab. 1985 Jul;61(1):7-11. — View Citation

White HD, Ahmad AM, Durham BH, Chandran S, Patwala A, Fraser WD, Vora JP. Effect of active acromegaly and its treatment on parathyroid circadian rhythmicity and parathyroid target-organ sensitivity. J Clin Endocrinol Metab. 2006 Mar;91(3):913-9. Epub 2005 Dec 13. — View Citation

Wongsurawat N, Armbrecht HJ, Zenser TV, Forte LR, Davis BB. Effects of hypophysectomy and growth hormone treatment on renal hydroxylation of 25-hydroxycholecalciferol in rats. J Endocrinol. 1984 Jun;101(3):333-8. — View Citation

* Note: There are 16 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Calcitriol/PTH	To describe baseline calcitriol/PTH status in patients with uncontrolled acromegaly, with subanalyses based on presence of hyperprolactinemia.; To assess the change in calcitriol/PTH levels after treatment with acromegaly, with subanalyses based on type of therapy (surgical or medical).; To evaluate the calcium and calcitriol/PTH levels in patients with acromegaly compared to patients with nonfunctioning pituitary adenomas, with subanalyses based on presence of hyperprolactinemia in either group.	Baseline and 3-6 months after trreatment of pituitary condition	No