Effects of cyclic pressure on bone marrow cell cultures

The present in-vitro study used bone marrow cell cultures and investigated the effects of cyclic pressure on osteoclastic bone resorption. Compared to control (cells maintained under static conditions), the number of tartrate resistant acid phosphatase (TRAP)-positive, osteoclastic cells was significantly (p<0.05) lower when, immediately upon harvesting, bone marrow cells were exposed to cyclic pressure (10-40 kPa at 1.0 Hz). In contrast, once precursors in bone marrow cells differentiated into osteoclastic cells under static culture conditions for 7 days, subsequent exposure to the cyclic pressure of interest to the present study did not affect the number of osteoclastic cells. Most important, exposure of bone marrow cells to cyclic pressure for 1 h daily for 7 consecutive days resulted in significantly (p<0.05) lower osteoclastic bone resorption and in lowered mRNA expression for interleukin-1 (IL-1) and tumor necrosisfactor-a (TNF-a), cytokines that are known activators of osteoclast function. In addition to unique contributions to osteoclast physiology, the present study provided new evidence of a correlation between mechanical loading and bone homeostasis as well as insight into the molecular mechanisms of bone adaptation to mechanical loading, namely cytokine-mediated control of osteoclast functions.     

Effects of growth factors on growth of stromal CFU-f in mouse bone marrow cell cultures]

Purified mouse IL-1 at doses 15-100 mu/ml inhibits the growth of stromal clonogenic cells /CFU-f/ both in full bone marrow cell cultures /F-cultures/ and in adherent bone marrow cell cultures /A-cultures/. Rec. human TNF-alpha inhibits growth of these cells at doses greater than 50 u/ml, but stimulates it /in 1.5 fold increase/at low doses /0.1-20 u/ml/ in cultures of both types. Rec. mouse IL-3 at doses 0.8-50 mu/ml slightly increases/in 1.6 fold increase/the in vitro growth of CFU-f and inhibits it at low doses in F-cultures. In A-cultures this factor stimulates CFU-f growth at all doses tested, but this stimulating effect takes place if only explantation density of mouse bone marrow cells in sufficiently high.     

Fibroblast colonies in monolayer cultures of human bone marrow

In a liquid culture of human bone marrow, the development of fibroblast colonies takes place on days 6 to 9. Twenty percent fetal calf serum is used as the stimulus for fibroblast colony growth. Human bone marrow cells are plated as 2 × 10₅ cells in the culture. Normal human bone marrow yields 47 ± 4 fibroblasts colonies per 2 × 10₅ cells plated. Bone marrow fibroblast cultures using agar or methylcellulose restrict colony formation. Marked colony suppression was observed in acute leukemia, and a discrete colony number was observed in hypoplastic anemia. This fibroblast culture method should be applied to a larger number of patients to determine whether it has a pathognomonic value and clinical significance.     

Bone tissue formation in organ cultures of human bone marrow

Bone formation in adult human bone marrow organ cultures is described. When culturing marrow fragments, thick bone lamina is formed. It has well-mineralized trabecular bone matrix with bone cells incorporated and is lined with osteoblast-like cells. In cultures of marrow deaggregated cell suspensions thin layers of the bone are only formed. Osteoclast-like cells develop in the cultures.     

Haemopoietic inductive capacity of irradiated stromal cell layers in human micro long-term bone marrow cultures

In a micro long-term bone marrow culture (LTBMC) system the effects of irradiation on confluent stromal cell layers were studied. In order to individually analyse the number of granulocyte-macrophage colony-forming cells (GM-CFC) per LTBMC a miniaturized human GM-CFC assay was established. The normalized GM-CFC numbers in the micro-assay compared well with data by the conventional GM-CFC assay. Pre-formed stromal cell layers were irradiated with doses up to 20 Gy and subsequently recharged with allogeneic bone marrow cells (BMC). Immediately before recharge the BMC were stromal cell-depleted by nylon wool filtration. When stromal cell-depleted BMC were inoculated on empty culture dishes, in vitro haemopoiesis rapidly declined. Sustained GM-CFC production, however, was seen when these cells were used as a second inoculum. It is concluded that irradiation doses of up to 20 Gy do not cause alteration of the haemopoietic inductive capacity of confluent stromal cell layers.     

1,25(OH)2D3 and calcipotriol (MC903) have similar effects on the induction of osteoclast-like cell formation in human bone marrow cultures

MC903 is a novel analogue of 1,25(OH)2D3 which exhibits similar inhibitory effects on cell proliferation and like, 1,25(OH)2D3, stimulates synthesis of osteoblast specific proteins by osteoblast-like cells in vitro. It is less active than 1,25(OH)2D3 in causing hypercalcemia in vivo. Since 1,25(OH)2D3 is known to stimulate bone resorption and increase the number of osteoclasts in several systems (in vivo and in vitro) we examined the effects of MC903 on the formation of osteoclast-like cells in vitro. As reported previously 1,25(OH)2D3 promoted the formation of multinucleated cells with phenotypic and functional characteristics of osteoclasts from adult human bone-marrow cultures at concentrations between 10(-8)M to 10(-12)M. Higher doses consistently suppressed multinucleated cell formation to values seen in the absence of 1,25(OH)2D3. Cells cultured in the presence of MC903 or for three weeks consistently induced the formation of multinucleated cells at concentrations 10(-8)M to 10(-12)M. As seen with 1,25(OH)2D3, MC903 also inhibited multinucleated cell formation at very high concentrations (10(-6)M). In two separate experiments MC903 appeared to be more potent than 1,25(OH)2D3 at lower concentrations (10(-10)M - 10(-12)M). From this study we conclude that MC903 is at least as potent as 1,25(OH)2D3 in inducing the formation human osteoclast-like cells in vitro. The decreased ability of MC903 to induce hypercalcemia in vivo is not therefore a result of a less marked effect than 1,25(OH)2D3 on the regulation of osteoclast formation.     

Value of exact focusing of extracorporeal shock waves (ESWT) in therapy of tendinitis calcarea. A prospective randomized study]

A controlled randomized study was designed to analyse the effect of extracorporeal shockwave therapy (ESWT) focussed on either the calcified region or the insertion of the supraspinatus tendon. The study included 50 patients who were treated with a Storz Minilith SI-1 prototype shockwave generator. In the treated group, 4000 impulses (ED+ 0.78 ml/mm2) were applied, under local anaesthesia to the insertion of the supraspinatus in 2 treatment sessions. Control patients received ESWT focussed on the calcified region. Follow-up examinations were carried out 12 weeks after treatment by an independent observer. We found functional improvement and pain reduction in both groups. Statistical analyses showed significant superiority of ESWT focussed on the calcified region for the parameters constant-score (primary endpoint, p < 0.001) and pain intensity (p = 0.001). For the treatment of calcific tendinitis affecting the supraspinatus, we recommend accurate fluoroscopy-controlled focussing of ESWT on the calcification. Focussing on the calcification rather than on the insertion of the supraspinatus tendon is significantly more effective. On the basis of our results, ESWT requires the use of suitable shockwave generators that permit accurate focussing.     

Nitric oxide mediates anti-inflammatory action of extracorporeal shock waves

Here, we show that extracorporeal shock waves (ESW), at a low energy density value, quickly increase neuronal nitric oxide synthase (nNOS) activity and basal nitric oxide (NO) production in the rat glioma cell line C6. In addition, the treatment of C6 cells with ESW reverts the decrease of nNOS activity and NO production induced by a mixture of lipopolysaccharides (LPS), interferon-gamma (IFN-gamma) plus tumour necrosis factor-alpha (TNF-alpha). Finally, ESW treatment efficiently downregulates NF-kappaB activation and NF-kappaB-dependent gene expression, including inducible NOS and TNF-alpha. The present report suggests a possible molecular mechanism of the anti-inflammatory action of ESW treatment.     

Radiosensitivity of colony-forming units of dog bone marrow in agar cultures]

Radiosensitivity of the bone-marrow colony-forming cells was determined by a modified method of hemopoietic cells cloning in vivo in semihard agar gel in diffusion chambers. Do for the commited precursor cells of granulopoiesis (CFUc) was 144 +/- 14.8 rad (n = 0.8), and Do for the precursor cells forming "stellate" colonies of fibroblast-like cells (PFUf) was 468 +/- 35.8 rad (n == 0.9). A conclusion was drawn that PFUf were referred to the class of stromal precursors of the hemopoietic organs. This system can be applied for a simultaneous study of the hemopoietic and stromal precursor cells in dogs.     

Renewal of hematopoietic stem cell clones in long-term bone marrow cultures

In long-term cultures of murine bone marrow, clonal succession of hemopoietic cells was observed as measured by karyologic analysis. There were high oscillations in self-renewal of CFUs in the cultures. A close correlation between the CFUmix karyotype and mitotic non-adherent cells in culture (but not between these cell types and CFUs) was revealed.     

Effects of lipoxygenase metabolites of arachidonic acid on the growth of human mononuclear marrow cells and marrow stromal cell cultures.

The effects of various lipoxygenase metabolites of arachidonic acid (AA) were investigated on the growth of freshly isolated human bone marrow mononuclear cells and marrow stromal cell cultures. LTB4, LXA4, LXB4, 12-HETE and 15-HETE (1 microM) decreased [3H]-thymidine incorporation on marrow stromal cell cultures without affecting cell number. Only 12-HETE showed a dose-response effect on [3H]-thymidine incorporation. While LTB4 (1 microM) decreased thymidine incorporation on marrow mononuclear cells, LTC4, LXA4, LXB4, 12-HETE and 15-HETE had no effect. The lipoxygenase inhibitor NDGA had no effect on both cell types suggesting no role of endogenous lipoxygenase metabolites on cell growth. These results suggest no important role of lipoxygenase metabolites of AA on the proliferation of human marrow mononuclear cells and marrow stromal cell cultures.     

Assessing the combined effect of surface topography and substrate rigidity in human bone marrow stem cell cultures

The combined effect of surface topography and substrate rigidity in stem cell cultures is still under‐investigated, especially when biodegradable polymers are used. Herein, we assessed human bone marrow stem cell response on aliphatic polyester substrates as a function of anisotropic grooved topography and rigidity (7 and 12 kPa). Planar tissue culture plastic (TCP, 3 GPa) and aliphatic polyester substrates were used as controls. Cell morphology analysis revealed that grooved substrates caused nuclei orientation/alignment in the direction of the grooves. After 21 days in osteogenic and chondrogenic media, the 3 GPa TCP and the grooved 12 kPa substrate induced significantly higher calcium deposition and alkaline phosphatase (ALP) activity and glycosaminoglycan (GAG) deposition, respectively, than the other groups. After 14 days in tenogenic media, the 3 GPa TCP upregulated four and downregulated four genes; the planar 7 kPa substrate upregulated seven genes and downregulated one gene; and the grooved 12 kPa substrate upregulated seven genes and downregulated one gene. After 21 days in adipogenic media, the softest (7 kPa) substrates induced significantly higher oil droplet deposition than the other substrates and the grooved substrate induced significantly higher droplet deposition than the planar. Our data pave the way for more rational design of bioinspired constructs.     

Natural suppressors of the human bone marrow tissue]

Proved the investigation devoted to the natural suppressors of healthy donors, patients with acute leukosis and solid tumors. The author made a comparative densitometric analysis of the bone marrow cells in these group.     

Human granulocyte colony stimulating factor: effects on human long-term bone marrow cultures

Human granulocyte colony stimulating factor (G-CSF) was previously shown to support the survival and proliferation of early myeloid progenitors (pre-CFU) that are capable of generating more mature CFU-GM progenitor cells. To evaluate the scope of action of G-CSF in the hierarchy of hematopoietic stem cells, we studied the effects of recombinant G-CSF (rhG-CSF) on long-term cultures of normal human bone marrow cells (LTBMC). We found that rhG-CSF predominantly influenced initial cell proliferation and expansion of CFU-GM progenitor cells in LTBMC before establishment of a confluent adherent layer. In rhG-CSF-treated LTBMC, the stromal cell layer was associated with a higher proliferative capacity and progenitor cell content as compared to control cultures. This effect was pronounced early after layer confluence and was gradually lost with culture time. rhG-CSF did not alter the duration of the productive phase of LTBMC, suggesting that it may not be active on the hematopoietic stem cells responsible for LTBMC propagation. Alternatively, stromal cells may exert tight regulatory control over progenitor cells, even in the presence of rhG-CSF.     

Studies on normal human bone marrow cultures in controlled environment thin-film culture systems

Summary Two thin film culture systems, the controlled environment steady state system (SS) and the rocker tube configuration of that system (RT), were used to identify some of the conditions that appear to maintain morphologic and functional characteristics of cells of human bone marrow explants in vitro. The systems configuration assured continual gassing, control and easy monitoring of the cultures. Cytocentrifuge preparations of media of specimens cultured in RT disclosed, though in decreasing numbers, various hematopoietic cells for periods exceeding one month. Hematopoietic cells shed from specimens cultured in the SS system were retained in the culture tubes; cells of the myelocytic series predominated for the first 2 weeks while an increasing number of monocytes and macrophages appeared in the media of older cultures. Histologic examination of cultured explants disclosed preservation of the marrow architecture and the persistence of hematopoietic cells. Specimens cultured in RT tubes tended to be less cellular than similar cultures placed in dialysis bags or as cultured in the SS system. Immunoglobulins (Ig) were released into the culture media at a constant rate throughout the period of culture. Specimens that were cultured at a controlled pH of 7.4 released 2 to more than 4 times as much Ig as similar specimens maintained at a pH level of 7.1. There were no definitive differences in Ig levels in the cultures maintained at comparable pH levels and overlaid with various CO₂ concentrations, i.e. 2%, 5%, 10%; similarly, no differences in Ig levels were found in specimens cultured in media containing fetal bovine sera as opposed to horse sera. Supported by U.S.P.H.S. Grant CA-5834 from the National Cancer Institute. Department of Medicine A. Department of Cell Physiology Department of Immunology and Immunochemistry.     

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

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.