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AzTrials

Blood Coagulation DisordersNCT00086476

Study of Megakaryocytes From Patients With Abnormal Platelet Vesicles

An observational study of Blood Coagulation Disorders, run by National Human Genome Research Institute (NHGRI) at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Congenital bleeding disorders characterized by abnormal platelet granules include Gray Platelet syndrome (GPS; defective alpha-granules), Hermansky-Pudlak syndrome (HPS; defective delta-granules), and combined alpha delta-storage pool deficiency (alpha delta-SPD). Read more about this study

Who is it for?
Ages 2 to 80 years
Conditions the study is for
Blood Coagulation Disorders
How many people
3 participants
Where
1 siteUnited States
Study dates
29 Jun 2004to 13 Jun 2011
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 2 to 80 years
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Who may be able to join

  • This protocol will include children and adults with a clinical diagnosis of GPS, HPS, isolated delta-SPD, combined alpha delta-SPD, Griscelli disease, Chediak Higashi syndrome, Wiskott Aldrich syndrome or Thrombocytopenia absent radius syndrome. Patients whose platelets exhibit abnormal intracellular vesicle morphology will also be eligible.

Who cannot join

  • Patients younger than 2 years and older than 80 years will be excluded. Patients with severe thrombocytopenia (fewer than 20 times 10(12) platelets/L) will be excluded.

Trial locations and contacts

1 site in 1 country.

United States1 site
  • National Institutes of Health Clinical Center, 9000 Rockville Pike

    Bethesda, Maryland, 20892

Other trials in United States

About this study

Official title: Investigations of Megakaryocytes From Patients With Abnormal Platelet Vesicles

Congenital bleeding disorders characterized by abnormal platelet granules include Gray Platelet syndrome (GPS; defective alpha-granules), Hermansky-Pudlak syndrome (HPS; defective delta-granules), and combined alpha delta-storage pool deficiency (alpha delta-SPD). Other diseases associated with variable defects in platelet gamma-granules include Chediak-Higashi, Griscelli, Wiskott-Aldrich, and Thrombocytopenia Absent Radius syndromes. These disorders are models for the study of organelle formation in megakaryocytes and platelets. Characteristics of megakaryocytopoiesis in these disorders have not been investigated because megakaryocytes could not be cultured from patients in sufficient quantities for experimental purposes. Recent advances have made it possible to culture megakaryocytes using serum-free media supplemented with recombinant human thrombopoietin (TPO). Such cultured human megakaryocytes, amplified from bone marrow-derived CD34+ stem cells, synthesize and store organellar proteins and produce functional platelets. In this protocol, we plan to obtain bone marrow aspirates from 40 children and adults (ages 2 to 80 years) with GPS, HPS, and related disorders. Patients admitted to the NIH Clinical Center on specific disease-related protocols will be enrolled in this protocol during their routine 3-5 day visits. We will culture megakaryocytes from CD34+ stem cells isolated from bone marrow aspirates. Studies of cultured megakaryocytes will include evaluation of granule membrane and soluble proteins using fluorescent antibodies and immunoelectron microscopy and comparison of RNA and protein expression patterns between normal and patient cells. Precautions will be taken to prevent the primary risk of the bone marrow aspiration, i.e., prolonged bleeding at the aspiration site. Standard diagnostic studies on the bone marrow sample may reveal information that may directly benefit patients. However, the broader benefit of this study is the acquisition of a better understanding of the characteristics of functional platelet disorders and the process of intracellular vesicle formation.

Read the detailed description

Congenital bleeding disorders characterized by abnormal platelet granules include Gray Platelet syndrome (GPS; defective alpha-granules), Hermansky-Pudlak syndrome (HPS; defective delta-granules), and combined alpha delta-storage pool deficiency (alpha delta-SPD). Other diseases associated with variable defects in platelet gamma-granules include Chediak-Higashi, Griscelli, Wiskott-Aldrich, and Thrombocytopenia Absent Radius syndromes. These disorders are models for the study of organelle formation in megakaryocytes and platelets. Characteristics of megakaryocytopoiesis in these disorders have not been investigated because megakaryocytes could not be cultured from patients in sufficient quantities for experimental purposes. Recent advances have made it possible to culture megakaryocytes using serum-free media supplemented with recombinant human thrombopoietin (TPO). Such cultured human megakaryocytes, amplified from bone marrow-derived CD34+ stem cells, synthesize and store organellar proteins and produce functional platelets. In this protocol, we plan to obtain bone marrow aspirates from 40 children and adults (ages 2 to 80 years) with GPS, HPS, and related disorders. Patients admitted to the NIH Clinical Center on specific disease-related protocols will be enrolled in this protocol during their routine 3-5 day visits. We will culture megakaryocytes from CD34+ stem cells isolated from bone marrow aspirates. Studies of cultured megakaryocytes will include evaluation of granule membrane and soluble proteins using fluorescent antibodies and immunoelectron microscopy and comparison of RNA and protein expression patterns between normal and patient cells. Precautions will be taken to prevent the primary risk of the bone marrow aspiration, i.e., prolonged bleeding at the aspiration site. Standard diagnostic studies on the bone marrow sample may reveal information that may directly benefit patients. However, the broader benefit of this study is the acquisition of a better understanding of the characteristics of functional platelet disorders and the process of intracellular vesicle formation.

Keywords
Gray Platelet Syndrome, Hermansky-Pudlak Syndrome, Storage Pool Deficiency, Organelle Formation, Megakaryocyte Development, Megakaryocytes, Platelets, Dense Granules, Alpha Granules, Lysosome-related Organelles, GPS, HPS, Griscelli Disease, Chediak Higashi Syndrome, Wiskott Aldrich Syndrome, Platelet, Congenital Bleeding Disorders, SAC, Vesicle
Medical subject headings
Blood Coagulation Disorders, Gray Platelet Syndrome, Hermanski-Pudlak Syndrome, Platelet Storage Pool Deficiency, Chediak-Higashi Syndrome, Wiskott-Aldrich Syndrome, Blister

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted2 Jul 2004 (estimated)
  2. Study start29 Jun 2004
  3. Study completion13 Jun 2011

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Enrolment
3 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT00086476
Sponsor's protocol ID
040226
Other IDs
04-HG-0226
Status last verified
13 Jun 2011
First submitted
1 Jul 2004
Last updated
2 Jul 2017
Results posted
No

Publications

  • Rendu F, Brohard-Bohn B. The platelet release reaction: granules' constituents, secretion and functions. Platelets. 2001 Aug;12(5):261-73. doi: 10.1080/09537100120068170.

    PubMed 11487378
  • White JG. Ultrastructural studies of the gray platelet syndrome. Am J Pathol. 1979 May;95(2):445-62.

    PubMed 453324
  • McNicol A, Israels SJ. Platelet dense granules: structure, function and implications for haemostasis. Thromb Res. 1999 Jul 1;95(1):1-18. doi: 10.1016/s0049-3848(99)00015-8.

    PubMed 10403682

Questions about this trial

What is this clinical trial studying?

An observational study of Blood Coagulation Disorders, run by National Human Genome Research Institute (NHGRI) at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 2 Jul 2017. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00086476, which also lists 3 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Jul 2017.

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