Modifications of bone and connective tissue after orthostatic bedrest.

摘要: Eight male volunteers were submitted to a 6-week anti-orthostatic bedrest trial followed by 1-month reambulation period. We prospectively monitored whole-body composition dual-energy X-ray absorptiometry, bone and connective tissue metabolism biochemical markers calcium regulating hormones 1–84 parathyroid hormone 1,25-dihydroxyvitamin D3. Bone mineral density (BMD) did not vary significantly; however, trend toward an increase in head BMD decrease trunk, lumbar vertebrae lower limb was observed. A the lean content occurred day 27 maximum 42 after beginning of bedrest; it normalized 30 bedrest. The serum levels both osteocalcin C-terminal crosslinked telopeptide type I collagen increased as consequence slight N-terminal propeptide III collagen, marker metabolism, observed during Except for extension all decreased baseline pre-immobilization recovery phase. Serum PTH D3 low period rose These results seem reflect early changes result unloading, but their order magnitude remains moderate, thus emphasizing necessity perform longer-duration trials.