151. Expansion of bone marrow adipose tissue during caloric restriction is associated with increased circulating glucocorticoids and not with hypoleptinemia
- Author
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Ormond A. MacDougald, Richard J. Sulston, Sebastian D. Parlee, William P. Cawthorn, Venkatesh Krishnan, Catherine M. H. Redshaw, Erica L. Scheller, Aaron A. Burr, Adam J. Bree, H. An Pham, Becky R. Simon, Benjamin Schell, Hiroyuki Mori, Arun K. Das, and Brian S. Learman
- Subjects
0301 basic medicine ,Leptin ,Male ,medicine.medical_specialty ,Bone density ,Adipose tissue ,030209 endocrinology & metabolism ,White adipose tissue ,Biology ,leptin ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Endocrinology ,Bone Density ,Bone Marrow ,Internal medicine ,medicine ,Animals ,Glucocorticoids ,Caloric Restriction ,Original Research ,Leptin Deficiency ,Adipogenesis ,Adiponectin ,glucocorticoids ,adiponectin ,Organ Size ,Mice, Inbred C57BL ,030104 developmental biology ,medicine.anatomical_structure ,Adipose Tissue ,Female ,Bone marrow ,Rabbits ,caloric restriction ,Bone marrow adipose tissue - Abstract
Bone marrow adipose tissue (MAT) accounts for up to 70% of bone marrow volume in healthy adults and increases further in clinical conditions of altered skeletal or metabolic function. Perhaps most strikingly, and in stark contrast to white adipose tissue, MAT has been found to increase during caloric restriction (CR) in humans and many other species. Hypoleptinemia may drive MAT expansion during CR but this has not been demonstrated conclusively. Indeed, MAT formation and function are poorly understood; hence, the physiological and pathological roles of MAT remain elusive. We recently revealed that MAT contributes to hyperadiponectinemia and systemic adaptations to CR. To further these observations, we have now performed CR studies in rabbits to determine whether CR affects adiponectin production by MAT. Moderate or extensive CR decreased bone mass, white adipose tissue mass, and circulating leptin but, surprisingly, did not cause hyperadiponectinemia or MAT expansion. Although this unexpected finding limited our subsequent MAT characterization, it demonstrates that during CR, bone loss can occur independently of MAT expansion; increased MAT may be required for hyperadiponectinemia; and hypoleptinemia is not sufficient for MAT expansion. We further investigated this relationship in mice. In females, CR increased MAT without decreasing circulating leptin, suggesting that hypoleptinemia is also not necessary for MAT expansion. Finally, circulating glucocorticoids increased during CR in mice but not rabbits, suggesting that glucocorticoids might drive MAT expansion during CR. These observations provide insights into the causes and consequences of CR-associated MAT expansion, knowledge with potential relevance to health and disease.
- Published
- 2016