Complex connections between bone and fat metabolism
Simon Collins, HIV i-Base
Several studies at the workshop suggested a greater complexity to the associations between bone and fat metabolism than are generally recognised.
In a plenary lecture Clifford Rosen from the Maine Medical Center Research Institute reviewed the pathophysiology of bone metabolism from the perspective of fat metabolism and potential mechanisms that might connect them. Bone health is receiving increased attention as a management issue, especially as antiretrovirals (irrespective of regimen) are associated with both reduced bone density and increased fracture rates. This talk suggested that bone and fat changes are related.
This lecture focused on the common ancestry of bone and fat cells – both deriving from the same mesenchymal stem cell lineage.
Visceral fat can produce endocrine factors that contribute to reduced bone density an fat redistribution is closely connected to glucose intolerance and abnormal skeletal remodeliing.
Fat distribution is also not just associated with increases in visceral adipose tissue but also marrow adiposity, which may therefore be the major pathogenic feature of HIV-related bone loss. Marrow fat, thought to be brown fat, may be also be acting as a compensatory support mechanism to support skeletal strength in the context of reduce bone density.
Rosen C. Body composition, fat and bone: whats the connection to drugs and HIV? Session IV plenary, 12th International Workshop on Adverse Drug Reactions and Co-morbidities in HIV Infection, 3-6 November 2011, London. Webcast online.