Looking at Mountains: Role of Sustained Hypoxia in Regulating Bone Mineral Homeostasis in Relation to Wnt Pathway and Estrogen

Bone mineral metabolism and different indices of skeletal health of Ladakhi women living at high altitude

“…BAP is major regulator of bone mineralization and hence major bone formation marker [ 18 ]. Nakamaru et al [ 3 ] reported similar BAP levels after 10–20 years of mountaineering among male and female mountaineers. Our lab has previously shown decreased BAP levels in low lander soldiers exposed to both extreme and HA [ 7 ].…”

“…Bone is a highly dynamic tissue undergoing continuous remodeling with bone resorbing osteoclasts digesting the bone matrix and providing site for bone forming osteoblasts to lay new bone matrix [ 17 ]. Studies have also reported changes in biochemical and hormonal markers of bone remodeling in low landers upon exposure to HA [ 3 ]. BAP is major regulator of bone mineralization and hence major bone formation marker [ 18 ].…”

“…However, ALP levels were increased on exposure to HA but decreased in those deinducted from extreme altitude [ 6 ]. Ranhotra and Sharma [ 3 ] have reported increased ALP in high-lander of 1495 m, at Mizoram India due to increased bone turnover among high-landers. Increased ALP was also reported by Ramirez et al [ 19 ] in natives residing at 3000 m of southern Colombian Andes to sea level population.…”

“…As reviewed by Aparna et al [ 21 ] nearly 50–94% of healthy controls in community based Indian studies have vitamin D deficiency. Despite increased ultraviolet radiation at HA, most studies have reported low vitamin D among HA dwellers and sojourns [ 3 ]. Vitamin D deficiency was reported in high and moderate altitudes of Indian subcontinent at the Lahaul and Spiti valley located above 4000 m and Kashmir valley located at 1615 m, respectively [ 22 , 23 ].…”

“…The bone strength parameters such as maximum load, stiffness, young's modulus were significantly reduced at simulated altitudes in rat models as well. Low oxygen tension has been reported to inhibit the formation and activity of osteoblasts thereby limiting bone formation and stimulating bone resorption by accelerating formation and activity of osteoclasts in many reports but contradictory results have also been reported [ 3 ].…”