Variations of fat tissue fraction in abnormal human bone marrow depend both on size and number of adipocytes: a stereologic study

Studies dealing with the number or size of individual adipose cells in abnormal human bone marrow are lacking. To ascertain whether variations in fat tissue fraction depend on the size of individual adipocytes or their number or both, a stereologic study of 30 human bone marrow specimens (10 with aplasia, 10 with hyperplasia, and 10 with dysplasia) was performed. A total of 23,435 adipocyte profiles were measured and two stereologic parameters were obtained in each specimen: mean diameter and number of cells per mm3 of bone marrow. The fat tissue fraction correlated positively with the size (r = .79; P less than .001) and the number/volume (r = .77; P less than .001) of adipocytes. The significance of both adipocyte size and adipocyte number/volume was confirmed by stepwise multiple regression, in which the size alone explained 62.5% of fat tissue fraction and both size and number/volume explained 95.8% of fat tissue fraction. These results are discussed from a pathophysiologic point of view.     

Phenotypic analysis of a large number of normal human bone marrow sample by flow cytometry

Summary Bone marrow aspirates from 48 healthy donors (34 adults, 14 children) were analyzed by flow cytometry (FACS Analyzer) after purification of low-density bone marrow cells (Ld BMC) on a density gradient (d = 1,077) and labelling with 23 anti-hematopoietic cell monoclonal antibodies. Based on physical properties, these Ld BMC could be divided into four different populations called E, My, Mo and L, which comprised 14% ± 9%, 31% ± 16%, 10% ± 5% and 45% ± 14% of these cells, respectively. The phenotypic analysis of these different populations enabled the identification in E, of erythrocytes (Glycophorin A+, Rhesus D+, but negative for early erythroid differentiation markers such as the transferrin receptor (Tf. R) and the FA6-152 antigen); in My of cells of the myeloid lineage (VIM2+, HLA DR–); in Mo of cells of the monocytic lineage (VIM2+, CD14+) plus some myeloblasts (VIM2+, CD14–, HLADR+) and finally in L of a heterogeneous population including: 1. T lymphocytes labelled to the same extent by CD2, CD3, CD5 and CD6 (28% ± 10%), B lymphocytes assessed by CD19 and CD20 (12% ± 8%), Pre-B cells (CD10+ = 8% ± 7%), less than 5% of natural killer cells (CD16+ or Leu7+) and finally, less than 6% of myelomonocytes (CD14+ and/or VIM2+). 2. The erythroid lineage (rhesus D+ = 42% ± 20%, Tf.R+ and FA6-152+ = 32% ± 12%). 3. Undifferentiated cells or progenitor cells (CD34+ = 7% ± 5%). 4. Cells unlabelled by any antibodies (approximately 6%). We observed no difference between bone marrow samples from adults or children, with respect to physical properties, and with all but four immunological markers. A significantly higher proportion of B cells (CD19+ and CD10+) (P<0.001) and undifferentiated cells (CD34+ and HLADR+) (P<0.02) was observed in children. These data, obtained from a large number of bone marrow samples, could be used to quantify the imbalance of some bone marrow disorders.     

Alkaline phosphatase positive precursors of adipocytes in the human bone marrow

Developing fat cells in the bone marrow of leukaemic patients treated with chemotherapy were found to be endowed with membrane-bound alkaline phosphatase. Since alkaline phosphatase is a cytochemical marker of 'reticular' cells, this observation provides cytochemical evidence that reticular cells may convert to adipocytes when marrow cellularity abruptly decreases.     

No stimulative effect of adipocytes on hematopoiesis in long-term human bone marrow cultures

Long-term cultures of human bone marrow were established for 5-13 wk to study the role of adipocytes in sustaining hematopoiesis. At weekly intervals, the numbers of nucleated cells and granulocyte-macrophage progenitor cells (GM-CFU) in culture were estimated in relation to the numbers of fat-containing cells present in the adherent stroma layer. In these quantifications, the numbers of GM-CFU trapped in the adherent cell layer were considered separately. It was found that the presence of adipocytes did not correlate with more active hematopoiesis. Fat cells appeared at late stages when successful cultures were being exhausted or early in cultures with poor activity. These observations suggest that human marrow continuous hematopoiesis in vitro, unlike hematopoiesis in the analogous murine bone marrow cultures, does not depend on the presence of adipocytes.     

Independence of megakaryocyte number and size in long-term cultures of normal mouse marrow

Megakaryocytopoiesis was evaluated in long-term cultures of normal murine marrow to determine whether the number and size of megakaryocytes were independent or interdependent. Numbers of megakaryocytes and granulocytes varied widely in different experiments, due, in part, to varying concentrations of hydrocortisone in the culture medium. The sizes of acetylcholinesterase-positive cells were the same in cultures with as much as a 20-fold difference in megakaryocyte numbers. These results indicate that, in the closed culture system containing normal stromal cells, megakaryocyte size and number are not reciprocal as they were in many previously reported cultures of S1/S1d mouse marrow. The results suggest that separate stromal functions may determine precursor cell proliferation and nuclear endomitosis in megakaryocytes in vitro. The relationship of these findings to regulation of megakaryocytopoiesis in vivo remains speculative.     

Trochanter bone marrow: a source of normal human colony forming cells.

In vitro studies of human hemopoiesis are often limited by the availability of normal bone marrow. We have overcome this difficulty by taking advantage of the bone marrow fragments removed during total hip replacement. We report here a comparative study of the colony forming capacity of trochanter and sternal or iliac crest marrow from five hematologically normal donors. Our data indicate that trochanter marrow is a reliable source of normal in vitro granulocyte/macrophage colony forming cells.     

Age-related changes in human memory: normal and abnormal

The evaluation of memory complaints in the elderly is one of the major challenges in geriatric medicine. Determining this deficit as either age-related change or dementia is a frequent problem in primary care practice. A careful history, an interview of a collateral source, and neuropsychological tests will shed light on the seriousness of the memory complaint. Several factors affect memory function of the elderly: anxiety, depression, and failure to use specific learning strategies commonly used by younger age groups. Memory training programs using mnemonics, lists, categorization, visual aids, rehearsal, and imagery may improve memory function.     

Effect of cytosine arabinoside on differentiation of normal human bone marrow cells

Human normal bone marrow cells were evaluated for alteration of differentiation after exposure for seven days to 10(-12)-10(-9) M cytosine arabinoside (ARA-C) in liquid culture. An increased number of induced cells had the morphologic appearance of mature monocytes-macrophages; they adhered to petri dishes, reacted positively to fluoride-sensitive naphthyl acetate esterase, and specifically bound My4 monoclonal antibody (MCAb). Assessment of phagocytosis and killing of Candida albicans (CA) by cultured monocytes-macrophages exposed to ARA-C demonstrated that treated cells had the same capacity to phagocytose and kill CA as did untreated cells. In semisolid culture, low doses of ARA-C did not affect myeloid colony growth. These studies indicate that ARA-C enhances monocytic differentiation of normal human bone marrow cells in liquid culture.     

Effects of rebreathing conditions and body size on normal human lung tissue volume

To evaluate the consequences of breathing pattern variations inherent to lung disease on the rebreathing measurement of lung tissue volume (Vt), we carried out a study of ten normal human subjects in whom we assessed the effects of changes in rebreathing volume (Vreb), additional deadspace volume (AVD), respiratory rate (RR), and body height. Vt and alveolar volume (VA) were determined from the end-tidal concentrations of acetylene and helium. We performed Vt measurements using different combinations of Vreb (20, 30 and 50% of predicted vital capacity), of AVD (0, 100, and 200 ml) and of RR (10, 25, and 40 br.min-1). Only slow RR (10 br.min-1) resulted in a higher Vt (p less than 0.001). An increase in Vreb induced an increase in VA but not in Vt. VA and Vt were positively correlated with the height of the subjects. We conclude that, in normal subjects, Vt increases: 1) with the height of subjects; and 2) when the respiratory rate is low. Interpretation of Vt results must take into account these two variables.     

Lipogenesis in human adipose tissue in vitro: effect of fat cell size on some enzymatic activities.

The incorporation of [1-C14] palmitate into palmitoyl CoA and triglycerides by homogenates of human adipose tissue have been studied. Adipose tissue samples were taken from three sites varying in adipocytes size (omentum, subcutaneous abdominal wall, buttock). The donors were normal weight women of constant weight. A significant positive correlation was found between initial velocity of palmitoyl CoA synthetase (EC 6.2.1.3) and total [1-C14] palmitate incorporation into triglycerides on one hand and adipocyte cell size on the other hand : these relations with cell size were apparent both within and between individuals. The mechanism of this "size effect" which is unrelated to the higher protein content of larger cells, is still unexplained. Lipogenesis, like most of the metabolic activities of adipose tissue increases with enlarging cell size. Acceleration of a lipogenesis-lipolysis cycle could constitute an energy wasting system able to limit the volume of the adipocytes.     

Growth of erythroid colonies in agar cultures of normal human bone marrow

Summary The use of methylcellulose (MC) gels or plasma clots, for the support of human erythropoiesis in vitro, is associated with several technical disadvantages. Substitution of soft agar offers the prospect of overcoming these difficulties. In comparative studies, normal human bone marrow cells were cultured with erythropoietin (Epo) in agar (0.1%–0.3%) and MC. Concentrations of 0.175% and 0.2% agar proved to be optimal with respect to the combination of cloning efficiency and colony density. Further morphological examination revealed that subcolony formation in erythroid bursts was influenced by gel viscosity. In additional experiments, miniaturising the assay system, to 0.25 ml culture volumes, increased cloning efficiency and reduced Epo utilization. These results confirm and expand earlier observations, and support a preference for the general use of agar in human erythroid cell cultures.     

应用3.0T磁共振IDEAL-IQ检测椎体骨髓脂肪分数诊断骨质疏松的效能评价

目的 评价3.0T磁共振最小二乘估算法迭代水脂分离定量技术(IDEAL-IQ)检测椎体骨髓脂肪分数(FF)诊断骨质疏松的效能。方法 选择2021年2月至2022年2月在该院进行健康体检者51名,其中男25名,女26名。采用双能X射线骨密度仪(DXA)检测骨密度值(T值),采用3.0T磁共振IDEAL-IQ检测椎体骨髓FF值,两项检查在同一天完成。以DXA检查结果将研究对象分为骨质正常组(T值≥-1.0 SD,25例)和骨质疏松组(T值≤-2.5 SD,26例)。比较两组FF值,并分析FF值与T值的相关性。采用ROC曲线评估FF值诊断骨质疏松的效能。结果 与骨质正常组相比,骨质疏松组年龄、FF值较大,T值较小,差异有统计学意义(P<0.05)。Spearman秩相关分析结果显示,FF值与T值呈负相关(r_s=-0.642,P<0.001)。ROC曲线分析结果显示,FF值可用于诊断骨质疏松[AUC(95%CI)=0.922(0.879～0.965),P<0.001],最佳截断值为50.42%,其对应的灵敏度为88.10%,特异度为82.60%。结论 3...     

Turning the spotlight on bone marrow adipocytes in haematological malignancy and non-malignant conditions

Whilst bone marrow adipocytes (BMAd) have long been appreciated by clinical haemato-pathologists, it is only relatively recently, in the face of emerging data, that the adipocytic niche has come under the watchful eye of biologists. There is now mounting evidence to suggest that BMAds are not just a simple structural entity of bone marrow microenvironments but a bona fide driver of physio- and pathophysiological processes relevant to multiple aspects of health and disease. Whilst the truly multifaceted nature of BMAds has only just begun to emerge, paradigms have shifted already for normal, malignant and non-malignant haemopoiesis incorporating a view of adipocyte regulation. Major efforts are ongoing, to delineate the routes by which BMAds participate in health and disease with a final aim of achieving clinical tractability. This review summarises the emerging role of BMAds across the spectrum of normal and pathological haematological conditions with a particular focus on its impact on cancer therapy.