Bone marrow adipocytes in haematological malignancies.

Bone marrow adipocytes (BMAs) derived from mesenchymal stem cells (MSC) are an active and significant element of the bone marrow microenvironment. They are involved in metabolic functions, complex interactions with other stromal cells, and in the development and progression of tumours. Currently, there is little data regarding the role of BMAs in haematological malignancies. Due to this, we have attempted to characterise the BMAs in these malignancies in terms of quantity and morphology. Our study included 30 patients aged 22-76 with myelo- (n=17) and lymphoproliferative malignancies (n=13), both with and without bone marrow infiltration. Trepanobioptate was the evaluated material. The number and diameter of BMAs were measured, and the percentage of adipocytes (adipocyte fraction - AF), hematopoietic cells (hematopoietic fraction - HF) and trabecular bone (trabecular bone fraction - BF) was calculated. The obtained results were considered against the clinical parameters of age, sex, body weight, body surface area (BSA) and body mass index (BMI). We observed that as age increases, the number of BMA/mm2 , the diameter of adipocytes and AF increase while BF and HF decrease. However, this relationship was not statistically significant. A significant correlation of BMA parameters was also not found in relation to weight, BMI and BSA, and the number and diameter of BMAs were comparable in both sexes. The trepanobioptate of infiltrated bone marrow showed a decreased number of BMA/mm2 compared to the trepanobioptate from bone marrow without infiltration (97.44±69.16 vs. 164.14±54.16; p=0.010) with a marked difference in men (69.75±65.26 vs. 180.33±60.40; p=0.007). These trepanobioptate also showed an increase in the number of BMA/mm2 with age (r=0.472; p=0.041), and with an increase of BMI, an increase in diameter of BMAs (r=0.625; p=0.007) and AF (r=0.546; p=0.023). The number and size of BMAs, as well as AF, BF and HF in patients with myeloproliferative malignancies did not differ significantly compared to patients with lymphoproliferative malignancies.