Markers of bone metabolism during 14 days of bed rest in young and older men
نویسندگان
چکیده
OBJECTIVE We aimed at comparing markers of bone metabolism during unloading in young and older men, and to assess countermeasure effectiveness. METHODS 16 older (60±2 years) and 8 younger men (23±3 years) underwent bed rest (BR) for 14 days. A subgroup of the Older performed cognitive training during BR and supplemented protein and potassium bicarbonate afterwards. Biochemical markers of bone and calcium/phosphate metabolism were assessed. RESULTS At baseline urinary NTX and CTX were greater in younger than in older subjects (P<0.001), but increased during BR (P<0.001) by a similar amount (P>0.17). P1NP was greater in young than in older subjects (P<0.001) and decreased during BR in the Young (P<0.001). Sclerostin increased during BR across groups (P=0.016). No systematic effects of the countermeasure were observed. CONCLUSION In men, older age did not affect control of bone metabolism, but bone turnover was reduced. During BR formation markers were reduced only in younger men whereas resorption markers increased to a comparable extent. Thus, we assume that older men are not at an elevated, and possibly even at a reduced risk to lose bone when immobilized.
منابع مشابه
Sex‐specific responses of bone metabolism and renal stone risk during bed rest
The purpose of this study was to directly assess sex differences in bone loss, bone biochemistry, and renal stone risk in bed rest. Bed rest simulates some spaceflight effects on human physiology and can be used to address the potential existence of sex-specific effects on bone metabolism and renal stone risk in space. We combined data from the control subjects in five head-down-tilt bed rest s...
متن کاملBone metabolism and nutritional status during 30-day head-down-tilt bed rest.
Bed rest studies provide an important tool for modeling physiological changes that occur during spaceflight. Markers of bone metabolism and nutritional status were evaluated in 12 subjects (8 men, 4 women; ages 25-49 yr) who participated in a 30-day -6° head-down-tilt diet-controlled bed rest study. Blood and urine samples were collected twice before, once a week during, and twice after bed res...
متن کاملSclerostin and DKK1 levels during 14 and 21 days of bed rest in healthy young men.
OBJECTIVES Wnt signaling pathway may be crucial in the pathogenesis of disuse-induced bone loss. Sclerostin and DKK1, antagonists of the Wnt signaling pathway, were assessed during immobilization by bed rest in young, healthy people. METHODS Two bed rest studies were conducted at the German Aerospace Center in Cologne. 14 days of 6° head-down-tilt bed rest were applied to eight healthy young ...
متن کاملEffects of 14 days of bed rest and following physical training on metabolic cost, mechanical work, and efficiency during walking in older and young healthy males
In this study, we investigated: i) the effects of bed rest and a subsequent physical training program on metabolic cost (Cw), mechanical work and efficiency during walking in older and young men; ii) the mechanisms underlying the higher Cw observed in older than young men.Twenty-three healthy male subjects (N = 16 older adults, age 59.6±3.4 years; N = 7 young, age: 23.1±2.9 years) participated ...
متن کاملSerum sclerostin increases in healthy adult men during bed rest.
CONTEXT Animal models and human studies suggest that osteocytes regulate the skeleton's response to mechanical unloading in part by an increase in sclerostin. However, few studies have reported changes in serum sclerostin in humans exposed to reduced mechanical loading. OBJECTIVE We determined changes in serum sclerostin and bone turnover markers in healthy adult men undergoing controlled bed...
متن کامل