Effects of Abnormal Loading on Tibiofemoral Articular Cartilage Composition
Joint Agency Name:
PI Name:
Souza, Richard B.
PI Phone:
510-235-1978
PI Email:
richard.souza@radiology.ucsf.edu
Fax:
PI Organization Type:
UNIVERSITY
Organization Name:
University of California, San Francisco
PI Address 1:
185 Berry Street, Suite 350
PI Address 2:
Radiology
PI Web Page:
City: San Francisco
State: CA
Zip Code: 94107
Congressional District: 8
Comments:
Project Type:
GROUND
Solicitation:
NSBRI-RFA-08-03
Start Date:
11/01/2008
End Date:
10/30/2010
Fiscal Year:
2010
No. of Post Docs:
1
No. of PhD Degrees:
1
No. of PhD Candidates:
1
No. of Master' Degrees:
0
No. of Master's Candidates:
0
No. of Bachelor's Degrees:
0
No. of Bachelor's Candidates:
0
Monitoring Center:
NSBRI
Contact Monitor:
Contact Phone:
Contact Email:
Flight Program:
Flight Assignment:
Key Personnel Changes/Previous PI:
COI Name:
COI Institution:
Grant/Contract No.:
NCC 9-58-PF01903
Performance Goal No.:
Performance Goal Text:
Task Description:
POSTDOCTORAL FELLOWSHIP.
While several studies have investigated the influence of long-duration space flight on muscle and bone tissue, it remains unclear how unloading influences cartilage health. It has been shown in animals that decreased loading results in cartilage deterioration with compositional changes similar to those of osteoarthritis (OA). However, it is unknown if these same changes are experienced in astronauts during space flight. If long-duration unloading results in biochemical changes within the cartilage, it may be a medical risk-factor for the development of OA later in life. OA is a progressive degenerative disease that is characterized by changes in proteoglycan and water content. Recent advancement in MR technology allow for an increased ability to monitor these biochemical levels in vivo. Furthermore, the reversibility reported in animal work with remobilization has yet to be observed in humans. The proposed study will utilize state-of-the-art MR techniques to monitor knee cartilage composition with non-weight-bearing (simulated zero-gravity) and return to full-weight-bearing (relative increased loading). The primary objective of this proposal is to quantify changes in cartilage composition with loading deprivation using advanced MR techniques (including T2 and T1rho relaxation time mapping). A secondary objective is to demonstrate reversibility of compositional changes of articular cartilage associated with OA in vivo. The results of this study are necessary to determine if biochemical changes associated with early OA occurs in humans after a period of non-weight-bearing and to determine how these changes respond when returning to full weight bearing. Future studies will use this information to design cartilage-protecting protocols of in-space exercise programs as well as strategies for post-flight re-integration into full-gravity conditions.
Research Impact/Earth Benefits:
Beyond the important information for astronaut health that this study will provide, this study also provides valuable information for the orthopaedic surgeon. Patients with hip, knee, and ankle injuries regularly are instructed to eliinate weight-bearing for 6-10 weeks following surgeries and/or injuries. This study will shed light on the health of the cartilage following this non-weight-bearing period. It will be important for orthopaedic surgeons to prepare post-immobilization protocols that account for the findings of the current study to avoid cartilage injury following return to weight-bearing.
Task Progress:
Institutional Review Approval was received at the end of 2008. In January and February 2009, piloting and protocol development was completed. Between March 2009 and September 2009, eight subjects have been enrolled in the study. One subject failed to complete the follow-up session. Three subjects have completed all data collection sessions and four additional subjects are currently in the non-weight-bearing phase. Data analyis is being performed on an on-going basis and data analysis will continue as new data sets are completed.
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