If shown to be an effective countermeasure to space flight-induced bone loss, bisphosphonates could prevent or ameliorate several potential bone-related problems identified in NASA’s Bioastronautics Roadmap. In addition, if bisphosphonates improve the efficiency of in-flight exercise to maintain bone mass, then more crew time could be made available to improve other problem areas.
Determine the treatment effect of bisphosphonates [alendronate or zoledronic acid plus in-flight exercise (AL+EX, ZO+EX)] versus in-flight exercise alone (EX) on space flight induced bone loss. Measurements required: Percent change in femoral Quantitative Computed Tomography (QCT) values (volumetric trabecular Bone Mineral Density (BMD) of total hip, pre-flight versus R+5).
While on the ISS, Alendronate subjects will ingest a pill weekly. All subjects will conduct three urine collection sessions (early, mid, and late mission). Crewmembers will also take a daily Vitamin D supplement during the duration of the mission.
The Bisphosphonates experiment urine samples will be obtained using the Urine Collection Kit (UCK). The Urine Collection Kit (UCK) is a Nomex pouch containing polyethylene Urine Collection Devices (UCDs) with male or female adapters, biocide wipes, and gauze. Each UCD contains one mL of lithium chloride as a volume marker and a sample port for sample retrieval. The Urine Containment Bag (UCB) is a large Nomex container with absorbent material and a sealing zipper for disposal of filled UCDs. The Sample Tube Dispenser is a metal and plastic rack designed to secure 60 plastic 10 mL syringes. Each syringe has a barcode label and a capped tip designed to provide an interface to connect the syringe with the UCD for sample removal. The Inventory Management System (IMS) Barcode Reader (BCR) or Personal Digital Assistant (PDA) will be used to record samples. All samples will be frozen in the Minus Eighty Laboratory Freezer on ISS (MELFI) for preservation until return to the PI for analysis.
An interim review of the data for this study indicated that it was necessary to add a new control group whose results could be compared to those of crewmembers who have taken bisphosphonates. The original historical control group (14 crewmembers from early ISS flights) exercised using the Interim Resistive Exercise Device (IRED), while the bisphosphonate subject group (7 subjects, now complete) exercised on the newer Advanced Resistive Exercise Device (ARED). The new control group will help distinguish the relative effects of bisphosphonates versus the confounder of ARED. The control subjects will participate in essentially the same data collection protocol as the bisphosphonate group, but not take the oral or intravenous bisphosphonate.
This study is still in progress. However, some preliminary results are available from a publication available in Osteoporosis International.
In addition to pre- and post-flight measurements, the investigators compared their results to 18 astronauts who flew ISS missions and who exercised using an early model resistance exercise device, called the interim resistance exercise device, and to 11 ISS astronauts who exercised using the newer advanced resistance exercise device (ARED). Their findings indicate that the ARED provided significant attenuation of bone loss compared with the older device although post-flight decreases in the femur neck and hip remained. The combination of the ARED and bisphosphonate attenuated the expected decline in essentially all indices of altered bone physiology during space flight including: DXA-determined losses in bone mineral density of the spine, hip, and pelvis, QCT-determined compartmental losses in trabecular and cortical bone mass in the hip, calculated measures of fall and stance computed bone strength of the hip, elevated levels of bone resorption markers, and urinary excretion of calcium.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Expedition 18||10/12/2008||04/17/2009||187 days|
|Expedition 19||03/26/2009||10/11/2009||199 days|
|Expedition 20||05/27/2009||10/11/2009||137 days|
|Expedition 21||10/11/2009||12/01/2009||51 days|
|Expedition 22||11/30/2009||03/18/2010||109 days|
|Expedition 23||03/18/2010||06/01/2010||75 days|
|Expedition 25||09/24/2010||11/25/2010||31 days|
|Expedition 26||11/26/2010||03/16/2011||111 days|
|Expedition 27||03/14/2011||05/23/2011||70 days|
|Expedition 28||05/23/2011||09/15/2011||115 days|
|Expedition 29||09/16/2011||11/21/2011||40 days|
|Expedition 31||04/27/2012||07/01/2012||65 days|
|Expedition 34||11/18/2012||03/15/2013||117 days|
|Expedition 35||03/15/2013||05/13/2013||58 days|
|Expedition 36||05/13/2013||09/10/2013||166 days|
|Expedition 37||09/10/2013||11/10/2013||61 days|
|Expedition 38||11/10/2013||03/10/2014||120 days|
|Expedition 39||03/10/2014||05/13/2014||64 days|
|Expedition 40||05/13/2014||09/10/2014||133 days|
|Expedition 41||09/10/2014||11/09/2014||29 days|
|Expedition 42||11/10/2014||03/11/2015||121 days|
|Expedition 43||03/11/2015||06/10/2015||91 days|
|Expedition 44||06/10/2015||09/11/2015||93 days|
|Expedition 45||09/11/2015||12/11/2015||91 days|
|Expedition 48||06/18/2016||09/06/2016||80 days|
|Expedition 49||09/06/2016||10/30/2016||54 days|