Consequence of Lifetime Isolated Growth Hormone Deficiency

Growth hormone (GH) deficiency (GHD) in adulthood has been associated with changes in body composition (e.g. increased abdominal obesity, and reduced muscle mass), in organ functions (e.g. reduced cardiac systolic function), in metabolic parameters linked to increased risk of cardiovascular disease (e.g. increased serum total and LDL cholesterol, C reactive protein, and plasma fibrinogen), and with reduced bone density. These observations have been used to define the "adult GHD syndrome" and to advocate GH replacement therapy in GHD adults. However, most of the studies have been performed in patients who have had hypothalamic or pituitary diseases, and/or have undergone brain irradiation. Such patients are often chronically sick, and commonly lack other pituitary hormones, whose replacement therapies may not fully restore the physiological functions of the under-active glands. Reliable data on the existence of the AGHD syndrome and its response to GH therapy can be only obtained by studying patients that are otherwise healthy. However, isolated GH deficiency (IGHD) is a rare disease. In addition, up to 50% of patients who have been diagnosed with IGHD in childhood are no longer GH deficient as adults, making such study difficult to perform due to the scarcity of patients population. We have identified a very large homogeneous population of patients who have IGHD due to a homozygous mutation in the GHRH-receptor (GHRHR) gene that resides in a rural area of Brazil. None of the adult dwarf patients has ever been treated with hGH replacement. This population represents a unique model to study the effect of isolated lifetime lack of GH. We propose studies of physiological and metabolic parameters in subjects who are homozygous for this mutation and compare them with normal subjects residing in the same community.

The primary goal of this proposal is to determine the consequences of life-long lack of GH on body composition, muscle strength, cardiovascular status, cardiovascular risk factors, thyroid status and bone density and metabolism, and to test which of these parameters are reversed by a 6-month course of GH replacement therapy. In addition, we want to test the hypothesis that heterozygosity for this GHRHR mutation causes a phenotype that may be intermediate between the one present in homozygous normal subjects and in homozygous affected GHD patients. This is relevant because inactivating mutations in the GHRHR are being described with increasing frequency in populations of different genetic background, suggesting that individuals with faulty single GHRHR alleles may be present in significant numbers in the general population.

Study Overview

Status

Completed

Detailed Description

SPECIFIC AIM 1: To study anthropometric parameters, cardiovascular and metabolic status and cardiovascular risk profile, including inflammatory markers of cardiovascular relevance, muscle strength, bone density and bone metabolism, and thyroid status of twenty GH-naïve adult GHD subjects who are homozygous for a null GHRHR mutation and to compare them with twenty age- and sex- matched normal controls from the same population.

SPECIFIC AIM 2: To observe the changes in all the above parameters that occur in GHD subjects after a 6-months treatment with hGH replacement, and their reversibility after a 6-months washout period.

SPECIFIC AIM 3: To determine effect of heterozygosity for the GHRHR mutation. To this end, we propose to genotype a large number of apparently normal members of the Itabaianinha community with the goal of separating subjects homozygous for the wild-type allele from subjects heterozygous for the GHRHR mutation, and to compare their phenotype with the one observed in subjects homozygous for the wild type allele residing in the same geographical area.

Together, these studies will determine the effect of lifetime absence of GH on multiple organ functions and their response to hGH therapy, and will tell if heterozygosity for mutations in the GHRHR gene is associated with a detectable phenotype.

Study Type

Interventional

Enrollment (Anticipated)

400

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Sergipe
      • Aracaju, Sergipe, Brazil, 49060
        • Federal University of Sergipe

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Lifetime isolated and untreated growth hormone deficiency

Exclusion Criteria:

  • Age below 18 years, pregnancy, diabetes

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Body composition
Time Frame: after 6 months of GH and after wash out (6 and 12 months)
after 6 months of GH and after wash out (6 and 12 months)
Lipid levels
Time Frame: after 6 months of GH and after 6 and 12 months of wash out
after 6 months of GH and after 6 and 12 months of wash out
Heart function
Time Frame: after 6 months of GH and after 6 and 12 months of wash out
after 6 months of GH and after 6 and 12 months of wash out

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Collaborators

Investigators

  • Principal Investigator: Roberto Salvatori, MD, Johns Hopkins University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2005

Primary Completion (Actual)

December 1, 2009

Study Completion (Actual)

December 1, 2009

Study Registration Dates

First Submitted

September 6, 2005

First Submitted That Met QC Criteria

September 7, 2005

First Posted (Estimate)

September 8, 2005

Study Record Updates

Last Update Posted (Estimate)

June 15, 2010

Last Update Submitted That Met QC Criteria

June 13, 2010

Last Verified

June 1, 2010

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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