[Adaptation of human bone marrow adipose tissue to different grades of hemopoietic cellularity].

Purpose: To assess whether the variations in the number and size of the adipocytes are proportional, or not, to the changes of the fat tissue fraction (FF) associated to different degrees of hematopoietic cellularity of the bone-marrow.

Material And Methods: The material was made up of 28 specimens of bone marrow biopsy, from which 265 microscopic fields representing a wide range of FF were obtained. As index of proportionality, the ratio N/S (adipocyte number/size) was employed.

Results: The parameters FF and N/S showed a highly significant correlation (r = 0.89; p = 0.00000003) at low-normal FF range (< 40%), whereas at high FF range (> 40%), such a correlation was lacking (r = 0.01; p = 0.86).

Conclusion: At low-normal FF the adipocyte number and size vary proportionally. Conversely, at high FF, in some cases a more marked increase of number and in other instances of adipocyte size is detected. Further investigations are needed to find out the responsible factors for this different behaviour.