Last Published:  03/26/21 03:33:57 PM (Central)
Responsible Element: Human Health Countermeasures (HHC)
Status: Open
Initial/Present State:

The skeleton serves as a structural framework for protection of internal organs and for the attachment of muscles to enable mobility. However, the skeleton also serves as a mineral reservoir from which minerals are readily released by bone resorption in order to maintain mineral homeostasis. Currently, the circulating levels of proteins and excretion levels of minerals and degraded collagen molecules are used to reflect trends in bone breakdown, bone synthesis and bone cell activities. General mineral metabolism is also regulated by the endocrine system (i.e., calcium regulation hormones such as 1, 25-dihydroxyvitamin D or parathyroid hormone) and changes in mineral efflux/influx from the skeleton (i.e., bone turnover) might be predicted by changes in hormone levels. Therefore, clinical decisions to protect bone health can be made on the basis of changes in biochemical levels. Reports in the literature suggest that changes in bone turnover markers reflect the skeletal response to anti-resorptive therapies and may predict directional changes in bone mass and fracture risk. Moreover, accelerated rates of bone resorption suggest that increased, focal resorption pits are reducing bone quality. Biochemical assays, however, cannot be used to predict fracture risk for skeletal sites; a capability to monitor changes in bone mass during spaceflight is also required in order to detect if skeletal deconditioning is approaching the non-permissible outcome (established by Gap Osteo1).

Interim Stages (Sequential):
  1. New bone parameters/bone biomarker - to monitor during exploration class missions –are identified by a Research and Clinical Advisory Panel (RCAP) based upon data from terrestrial clinical arena. (5%)
  2. Recommendations are submitted to Human Health Countermeasures (HHC) for the development of new technologies/tests and to Exploration Medical Capability (ExMC) Elements. (5%)
  3. Verify ability of novel technologies/tests (for new bone parameter/biomarkers) to detect an effect size of spaceflight in a ground-based flight analog. (15%)
  4. Validate the technologies/tests (#3 above) for clinical utility - by accepted criteria (e.g., comparable to gold standard, precision, accuracy, response to therapy etc.) to ExMC. (40%)


  5. Verify the efficacy of clinically validated the technologies/tests (#4 above) in a flight study. (15%)
  6. Clinical-advisory panel formulates a clinical response, if possible, to the change in novel bone parameter during spaceflight, e.g., an identified threshold or trigger. (20%)
Provide inputs to ExMC on a ground-based prototype for measuring relevant bone biomarkers by establishing a) precision in serial measures, b) comparability to gold standard methods, c) an ability to detect an effect size of a pathology, d) an ability to monitor the progression of a disease or pathology, and e) an ability to detect a response to an intervention/countermeasure. Flight hardware for these new tests must also be flight-worthy with regards to power, mass, volume, time and expense.

Target for Closure
Hardware and analysis capabilities, with formulated set of Clinical Practice Guidelines (CPGs), developed for flight surveillance of bone turnover and of bone mass changes.
Risk Risk of Bone Fracture due to Spaceflight-induced Changes to Bone
You are here! Gap Osteo 5: We need an inflight capability to monitor bone turnover and bone mass changes during spaceflight.

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