Alginate microbeads as potential support for cultivation of bone marrow stromal cells

Alginate is currently being employed and explored for a broad range of biomedical and biotechnology applications, due to its biodegradability and simple procedure for cell immobilization. However, cell immobilization was mostly aimed for immunoisolatory and biochemical processing applications and far less is known about potentials of alginate as a substrate for tissue formation. In the present work, isolation, immobilization and cultivation procedures of murine bone marrow stromal cells (BMSC) were studied and standardized in order to establish the alginate-bioreactor culture system for chondrogenic and/or hematopoiesis-supportive tissue progression. Two techniques for cell immobilization based on alginate were investigated: entrapment within gel matrix using electrostatic droplet generation and simple cell adsorption onto gel surfaces. Alginate gels in forms of microbeads and discs with immobilized culture expanded BMSC were cultivated for up to 30 days and analyzed for surface properties, cell concentration, viability, and differentiation

Liposomes with alpha-tocopherol membrane

Liposomes, closed spherical structures formed by phospholipid bilayers, have been recognized as a controlled drug delivery system. We have studied the preparation and biocompatibility of liposomes based on soya phospholipids encapsulated with alpha-tocopherol. The binding efficiency of alpha-tocopherol was analysed by comparing two methods for liposome preparation: a) dry film (DFM) and b) solvent infusion method (SIM). The degree of encapsulation achieved (88-93%) suggested a high affinity of alpha-tocopherol for liposome membrane binding. The initial concentration of alpha-tocopherol had a significant effect on the degree of encapsulation, while the effect of method used was less pronounced. In general, a higher degree of encapsulation was achieved with smaller liposome size fractions. Based on an experimentally obtained size distribution function, it can be concluded that if smaller liposomes are used, SIM seems to be more efficient due to the higher content of smaller vesicles. The in vivo application of the liposomes to CBA mice confirmed the biocompatibility and nontoxicity of such preparations. The analysis of hematological parameters in peripheral blood (determination of mature blood cells with differential count) revealed that liposomes did not express cytotoxic effects on any of the parameters tested

Granulocyte and plasma cytokine activity in acute cadmium intoxication in rats

Changes in the number and ex vivo function of peripheral blood neutrophils were investigated following intraperitoneal administration of cadmium-chloride in rats. Besides a dose-dependent increase in the number of peripheral blood neutrophils, changes were found in the functional state of isolated polymorphonuclear leukocytes (PMNs). Increased spontaneous adhesion and activation, and TNF activity in a conditioned medium were observed in cultures of granulocytes in comparison to granulocytes from control (saline-treated) animals. Increased levels of plasma activity of inflammatory cytokines, tumor necrosis factor (TNF) and interleukin-6 (IL-6) were noted following cadmium administration. Cytological signs of pulmonary inflammation were revealed histologically and the majority of neutrophils recovered from the lungs by enzyme digestion exhibited a capacity of nitroblue tetrazolium (NBT) reduction. Our data demonstrate that acute cadmium intoxication leads to a systemic inflammatory response characterized by numerical and functional changes in the granulocyte compartment and to increased levels of inflammation-related cytokine activity in the circulation. Correlations between the increased number of peripheral blood neutrophils and IL-6 plasma activity (r = 0.776, p < 0.00001) and the number of neutrophils recovered from the lung tissue (r = 0.893, p < 0.00001) suggested that systemic cadmium-induced inflammation might be involved in the pulmonary toxicity of cadmium.nul

Cell support studies aimed for cartilage tissue engineering in perfused bioreactors

Cartilage tissue engineering based on chondrogenic cells seeded onto biodegradable polymer supports and cultivated in bioreactors can potentially become an effective method for creating functional tissue equivalents. Cultivation in perfused bioreactors can improve the uniformity and structure of the engineered tissues. We report studies of two different supports for immunobilization of mouse bone marrow stromal cells (BMSC) for cultivation in perfused bioreactors: fibrous polyglycolic acid (PGA) scaffolds and alginate microbeads

Granulocyte and plasma cytokine activity in acute cadmium intoxication in rats

Changes in the number and ex vivo function of peripheral blood neutrophils were investigated following intraperitoneal administration of cadmium-chloride in rats. Besides a dose-dependent increase in the number of peripheral blood neutrophils, changes were found in the functional state of isolated polymorphonuclear leukocytes (PMNs). Increased spontaneous adhesion and activation, and TNF activity in a conditioned medium were observed in cultures of granulocytes in comparison to granulocytes from control (saline-treated) animals. Increased levels of plasma activity of inflammatory cytokines, tumor necrosis factor (TNF) and interleukin-6 (IL-6) were noted following cadmium administration. Cytological signs of pulmonary inflammation were revealed histologically and the majority of neutrophils recovered from the lungs by enzyme digestion exhibited a capacity of nitroblue tetrazolium (NBT) reduction. Our data demonstrate that acute cadmium intoxication leads to a systemic inflammatory response characterized by numerical and functional changes in the granulocyte compartment and to increased levels of inflammation-related cytokine activity in the circulation. Correlations between the increased number of peripheral blood neutrophils and IL-6 plasma activity (r = 0.776, p < 0.00001) and the number of neutrophils recovered from the lung tissue (r = 0.893, p < 0.00001) suggested that systemic cadmium-induced inflammation might be involved in the pulmonary toxicity of cadmium.nul

The effect of IL-1 receptor antagonist on the proliferation of hematopoietic progenitor cells in regenerating bone marrow

To evaluate the involvement of IL-1 on bone marrow granulocyte-macrophage (CFU-GM) and erythroid (BFU-E and CFU-E) progenitor cell regeneration during the recovery of hematopoiesis after sublethal irradiation of CBA mice, we examined the effects of IL-1 receptor blockade by recombinant human IL-1 receptor antagonist (rhIL-1ra). The actual number of progenitors and proportion of these cells in S phase of the cell cycle were determined in regenerating bone marrow cells obtained 3 days after 2 Gy irradiation both following the in vivo administration of rhIL-1ra, as well as after the in vitro preincubation with increasing amounts of rhIL-1ra. The results revealed that rhIL-1ra decreased the number and the proportion of CFU-GM in the S phase in regenerating bone marrow. As concerning erythroid progenitors, rhIL-1ra treatment suppressed BFU-E and enhanced CFU-E-derived colony growth, indicating that the biological effects of IL-1 might be different depending on the stage of differentiation. The observed effects pointed to the importance of the basal levels of IL-1, as well as IL-1 receptor expression during the recovery of hematopoiesis.nul

The effect of IL-1 receptor antagonist on the proliferation of hematopoietic progenitor cells in regenerating bone marrow

To evaluate the involvement of IL-1 on bone marrow granulocyte-macrophage (CFU-GM) and erythroid (BFU-E and CFU-E) progenitor cell regeneration during the recovery of hematopoiesis after sublethal irradiation of CBA mice, we examined the effects of IL-1 receptor blockade by recombinant human IL-1 receptor antagonist (rhIL-1ra). The actual number of progenitors and proportion of these cells in S phase of the cell cycle were determined in regenerating bone marrow cells obtained 3 days after 2 Gy irradiation both following the in vivo administration of rhIL-1ra, as well as after the in vitro preincubation with increasing amounts of rhIL-1ra. The results revealed that rhIL-1ra decreased the number and the proportion of CFU-GM in the S phase in regenerating bone marrow. As concerning erythroid progenitors, rhIL-1ra treatment suppressed BFU-E and enhanced CFU-E-derived colony growth, indicating that the biological effects of IL-1 might be different depending on the stage of differentiation. The observed effects pointed to the importance of the basal levels of IL-1, as well as IL-1 receptor expression during the recovery of hematopoiesis.nul