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Study of Megakaryocytes From Patients With Abnormal Platelet Vesicles

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ClinicalTrials.gov Identifier: NCT00086476
Recruitment Status : Completed
First Posted : July 2, 2004
Last Update Posted : July 2, 2017
Sponsor:
Information provided by:
National Institutes of Health Clinical Center (CC)

Study Description
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Brief 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). 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.

Condition or disease
Blood Coagulation Disorders

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.
Study Design
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Study Type : Observational
Actual Enrollment : 3 participants
Official Title: Investigations of Megakaryocytes From Patients With Abnormal Platelet Vesicles
Study Start Date : June 29, 2004
Study Completion Date : June 13, 2011

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Groups and Cohorts
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Outcome Measures
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Eligibility Criteria
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Ages Eligible for Study:   2 Years to 80 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria
  • INCLUSION CRITERIA:

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.

EXCLUSION CRITERIA:

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.

Contacts and Locations
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Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00086476


Locations
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United States, Maryland
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Human Genome Research Institute (NHGRI)
More Information
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Publications:

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ClinicalTrials.gov Identifier: NCT00086476    
Other Study ID Numbers: 040226
04-HG-0226
First Posted: July 2, 2004    Key Record Dates
Last Update Posted: July 2, 2017
Last Verified: June 13, 2011
Keywords provided by National Institutes of Health Clinical Center (CC):
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
Additional relevant MeSH terms:
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Hemostatic Disorders
Blood Coagulation Disorders
Hematologic Diseases
 Vascular Diseases
Cardiovascular Diseases
Hemorrhagic Disorders