Inflammatory/haematopoietic cytokine production by human bone marrow adipocytes

Adipocytes are now considered as secretory and endocrine cells. White and b rown adipocytes synthesize and secrete a variety of cytokines, among a numb er of peptide and non-peptide products. Some of these cytokines, particular ly IL-6 and TNF-alpha, appear multifunctional since they may be involved in the control of adipose mass, inflammatory response and haematopoiesis. Bon e marrow adipocytes are another abundant type of adipocytes, but their prec ise role in humans is poorly understood. In the present study, me demonstra te that, in contrast to non-medullary adipocytes, human bone marrow adipocy tes in primary culture secrete only trace amounts of IL-1 beta and TNF-alph a, but, they secrete significant and regulated levels of IL-6. These result s reinforce the concept of functional heterogeneity of adipose tissues acco rding to their anatomical localization, and indicate that bone marrow adipo cytes may contribute to the complex network of cytokines involved in the co ntrol of haematopoiesis.