Age-related differences in the effect of in vivo administration of indomethacin on hemopoietic cell lineages of the spleen and bone marrow of mice

Dietary consumption of Echinacea by mice afflicted with autoimmune (type I) diabetes: effect of consuming the herb on hemopoietic and immune cell dynamics

Epidemiological studies indicate that the incidence of Type 1 diabetes, an autoimmune disease, is rising rapidly. However, none of the current therapies produces life long remission, or can prevent the disease onset. The NOD (non-obese diabetic) mouse is currently regarded as an excellent animal model of human Type 1 diabetes. NKT cells are known to be fundamental in modulating the disease, yet they are numerically and functionally deficient in mammals bearing this disease. Indeed, the role of NK cells in inhibiting autoimmunity in general is well established. Immunoregulatory strategies are currently believed to be the way of the future with respect to modulating autoimmune diseases. Based on this hypothesis, and the fact that the herb, Echinacea, is a well demonstrated immunostimulant of NK cells in normal mice/humans, we aimed to investigate, in NOD mice, the effect of short term (days) and long term (months) daily dietary administration of Echinacea, on the absolute levels of NK cells, and five other classes of hemopoietic and immune cells, in the bone marrow and spleen. The results revealed that, in NOD mice, dietary Echinacea, resulted in a significant increase in the absolute numbers of NK cells, irrespective of feeding duration, in the spleen, and moreover, it actually stimulated NK cell production in their bone marrow birth site. We further found that there were transient, early (days), herb exposure-time-dependent, quantitative changes in several of the other hemopoietic and immune cells populations in both the bone marrow and spleen. We conclude that consumption of this herb by NOD mice, at least, has lead to no negative repercussions with respect to the hemopoietic and immune lineages, and secondly, the consistent, long-lasting immunostimulation only of NK cells, may lead to a possible new approach to the treatment of Type 1 diabetes.

Dietary Echinacea purpurea during murine pregnancy: effect on maternal hemopoiesis and fetal growth

BACKGROUND

The medicinal benefits of Echinacea sp. plants in several disease conditions, including insect bites, respiratory ailments, and even cancer and AIDS, have been touted for decades. Echinacea sp.-based phytoceuticals are among the top selling herbals in the Western marketplace today. However, evidence is very scant concerning the effects of using Echinacea species herbals during pregnancy. While available data indicates that fetal malformations do not occur during pregnancy in humans consuming this herb, there are no formal studies aimed at assessing the possibility that consuming Echinacea herbals may promote spontaneous abortions, thereby reducing the number of live births upon which to assess the presence or absence of malformations.

OBJECTIVES

We undertook a study in which pregnant mice were fed daily Echinacea purpurea from pregnancy onset until gestational days 10, 11, 12, 13, and 14.

METHODS

Maternal spleen and bone marrow were taken for enumeration of cells in each of five separate hemopoietic lineages/organ, and fetal status was recorded.

RESULTS

The data indicate that the significant, pregnancy-induced elevation in splenic lymphocytes and nucleated erythroid cells was all but eliminated in those females which consumed E. purpurea daily throughout their pregnancy. Moreover, consuming E. purpurea during pregnancy reduced the number of viable fetuses.

CONCLUSIONS

The data may be extrapolated to suggest that in humans, abstention from consuming Echinacea products during the early/mid stages of pregnancy, may be prudent.

Effect over time of in-vivo administration of the polysaccharide arabinogalactan on immune and hemopoietic cell lineages in murine spleen and bone marrow

Current evidence indicates an immunostimulating role for complex carbohydrates, i.e., polysaccharides, from several plant sources. In the present work, we determined the specific in vivo effects, with time of administration, of one such compound, a neutral arabinogalactan from larch not only on immune (lymphoid) cells, but also on natural killer (NK) lymphoid cells, as well as a variety of other hemopoietic cells in both the bone marrow and spleen of healthy, young adult mice. The latter were injected daily (i.p.) with arabinogalactan (500 microg in 0.1 ml pH 7.2 phosphate buffered saline-PBS) for 7 or 14 days. Additional, aged (1 1/2-2 yr) mice were similarly injected for 14 days only. Control mice were given the PBS vehicle in all cases, following the above injection regimen. Animals from all groups were sampled 24 h after the final injection and the immune and hemopoietic cell populations in the bone marow and spleen were assessed quantitatively. The results indicated that immediately following either 7 or 14 days of arabinogalactan administration to young, adult mice, lymphoid cells in the bone marrow were significantly decreased (p < 0.004; p < 0.001, respectively) relative to controls but remained unchanged at both time intervals in the spleen. NK cells, after 7 days of arabinogalactan exposure, were also decreased significantly in the bone marrow (p < 0.02), but unchanged in the spleen. After 14 days' exposure to the polysaccharide, NK cells in the bone marrow had returned to normal (control) levels, but were increased in the spleen (p < 0.004) to levels greater than 2-fold that of control. Among other hemopoietic cell lineages, none was influenced in the bone marrow or spleen by one-week administration of arabinogalactan; however, after two-week exposure, precursor myeloid cells and their mature (functional) progeny (granulocytes), were significantly reduced in the spleen (p < 0.043; p < 0.006, respectively), as were splenic monocytes (p < 0.001). These lineages in the bone marrow, however, remained steadfastly unaltered even after 14 days of continuous exposure to the agent. Of the vast cascade of cytokines induced in the presence of this polysaccharide, it appears that immunopoiesis- and hemopoiesis-inhibiting ones are most prevalent during at least the first two weeks of daily exposure.

Allergenic sensitization prevents upregulation of haemopoiesis by cyclo-oxygenase inhibitors in mice

1. We evaluated whether immunization affects bone-marrow responses to indomethacin, because allergenic sensitization and challenge upregulate responses to haemopoietic cytokines (including IL-5-driven eosinopoiesis) in murine bone-marrow, while indomethacin upregulates haemopoiesis and protects bone-marrow from radiation damage. 2. Progenitor (semi-solid) and/or precursor (liquid) cultures were established from bone-marrow of: (a) normal mice; (b) ovalbumin-sensitized mice, with or without intranasal challenge. Cultures were established with GM-CSF (2 ng ml(-1)) or IL-5 (1 ng ml(-1)), respectively, alone or associated with indomethacin (10(-7) - 10(-11) M) or aspirin (10(-7) - 10(-8) M). Total myeloid colony numbers and numbers of eosinophil-peroxidase-positive cells were determined at day 7. 3. In naïve BALB/c mice, indomethacin (10(-7) - 10(-9) M) increased GM-CSF-stimulated myeloid colony formation (P=0.003 and P=0.009, respectively). In contrast, it had no effect on bone-marrow of ovalbumin-sensitized and challenged mice. Indomethacin (10(-7) - 10(-9) M) also increased eosinophil precursor responses to IL-5 in bone-marrow of naïve (P<0.001 and P=0.002 respectively), but not sensitized-challenged mice. Aspirin (10(-7) M) had similar effects, equally abolished by sensitization. Enhancement of haemopoiesis by indomethacin required adherent cells from naïve bone-marrow. Nonadherent cells responded to IL-5 but not to indomethacin. Indomethacin was effective on bone-marrow from sham-sensitized, ovalbumin-challenged, but not from sensitized, saline-challenged mice. Plasma transfer from immune mice abolished eosinophil precursor responses to indomethacin in bone-marrow of naïve recipients. This was not prevented by previous removal of antibody from immune plasma. 4. COX inhibitors enhance haemopoiesis in naïve but not allergic mice. Responsiveness to indomethacin can be abolished either by active sensitization or by immune plasma transfer. Specific antibody is not involved.

The effect of immunization with killed tumor cells, with/without feeding of Echinacea purpurea in an erythroleukemic mouse model

OBJECTIVE

Tumor amelioration via vaccination/immunization is a practice for which considerable experimental and clinical support is growing. Combination therapies have proven to be more beneficial than treatment with single agents. We hypothesized that immunization of mice with killed erythroleukemia cells prior to the induction of erythroleukemia via injection of viable tumor cells, plus dietary administration of a known immuno-enhancing phytocompound, Echinacea purpurea, would be more effective than immunization alone.

DESIGN

A commercially available extract of E. purpurea root, already proven as a natural killer (NK) cell stimulant, was administered via the chow, for periods of 9 days or 3 months after the onset of leukemia to mice which had been injected (immunized) 5 weeks earlier with killed leukemia cells.

RESULTS

Immunized mice (+/- E. purpurea) had significantly prolonged life spans versus non-immunized mice, with an even greater proportion of hosts surviving long-term in the E. purpurea-fed group. NK cells, the mediators of nonspecific immunity and well-demonstrated mediators of tumor cytolysis, were very significantly elevated in immunized, leukemic mice receiving E. purpurea in their diet versus those receiving untreated chow. Early in tumor development (9 days), cells mediating specific immunity (T, B lymphocytes) were 10-12 times higher in absolute numbers in the spleens in all immunized, leukemic mice vs unimmunized, leukemic mice at the same stage of tumor progression.

CONCLUSIONS

The results demonstrate that combination therapy, involving specific tumor cell immunization, followed by daily phytotherapy (dietary E. purpurea), sensitized the immune cells and led to life span prolongation greater than that provided by immunization alone.

Modulation of erythropoiesis in rat bone marrow erythroblastic islands by cyclooxygenase inhibition

We designed our study to explore how the inhibition of prostaglandins (PGs) could affect erythropoiesis in bone marrow erythroblastic islands (EIs). To this end, we used hypoxic-stimulated rats-hypobaric hypoxia (42.55 kPa/6 h)-pretreated or not with indomethacin (4 mg/kg/3 days). Blood sampling was done at 0 h, 24 h, and 72 h after hypoxia. The study included estimations of the plasma erythropoietin (EPO) level (by radioimmunoassay), peripheral blood, number of EI from classes I to V per femur, rate of immature cell's differentiation into erythroblasts, and rate of repeated participation of macrophages in new EI reconstruction. Plasma EPO rose significantly (p < 0.01) in all hypoxic rats: 40.5+/-10.15 mU/ml and 46.75+/-16.28 mU/ml and at 0 h versus 13.83+/-6.82 mU/ml in controls. An increased rate of cell differentiation into erythroblasts in EIs (p < 0.01), an enhanced reconstruction in involuted EIs, and a reduced number of maturing EIs (p < 0.01) were observed in all hypoxic animals. However, in indomethacin-pretreated rats, the stimulation of bone marrow erythropoiesis was better expressed. Our results favor the concept that PG inhibition does not attenuate the erythropoietic response to hypoxia and support the hypothesis about the important role of EI macrophages as a local regulator of bone marrow erythropoiesis.

Decline in natural killer cell-mediated immunosurveillance in aging mice--a consequence of reduced cell production and tumor binding capacity

The mechanism(s) responsible for the functional deficiencies in aging mice of natural killer (NK) cells, the lymphocytes active in early neoplasia development, are unknown. The aim of the present study was to examine the effect of indomethacin, a prostaglandin synthetase inhibitor, and recombinant interleukin-2 (rIL-2), an NK cell stimulant, on the NK cell numbers and function of aging mice. This combination is highly effective in inducing proliferation and activation of the NK cells in young adult mice. Ten- to 13-month-old DBA/2 mice received either indomethacin daily for 9 days in their drinking water, or rIL-2 twice a day for 4 days, or both agents combined. Untreated aging mice had 50% fewer splenic NK cells than did young adult (5-8 weeks) DBA/2 mice, although bone marrow contained NK cell numbers similar to that of young adult mice. Neither indomethacin alone, rIL-2 alone nor the combination of both could induce an increase in NK cell numbers or function in aging mice. Radioautography combined with immunoperoxidase labelling techniques revealed that the production of new NK cells from the bone marrow of aging mice was significantly reduced relative to that of young adult mice. This was reflected in low numbers of newly formed NK cells accumulating in the spleens of aging mice. The target binding capacity, a necessary precytolytic event, of aging mouse NK cells was also reduced compared to that of young adult mice. The results suggest that the functional deficiencies of aging mouse NK cells are a consequence of multiple factors including an absolute loss of NK cells resulting from a reduced production of such cells in the bone marrow and a decreased capacity of NK cells to bind their tumor targets.

Leukocyte mobilization from the guinea pig spleen by muscarinic cholinergic stimulation

Important interactions between the immune system and the nervous and endocrine systems have become increasingly accepted. The present results demonstrate that the cholinergic agonist carbacholine greatly increased the number of granulocytes and lymphocytes in the splenic venous blood, but not arterial blood, shortly after administration to guinea pigs. The effect was largely blocked by pretreatment with atropine. In contrast, animals treated with indomethacin had a decreased number of leukocytes in both splenic venous and arterial blood. A decrease in relative splenic weight due to carbacholine treatment was also blocked by atropine. However, cholinergic leukocyte mobilization, or that previously observed after adrenergic stimulation, may not be caused by capsule contraction since it is not accompanied by mobilization of erythrocytes. Furthermore, indomethacin, which potentiates the response of splenic smooth muscle to adrenergic stimuli, blocked the effect of noradrenaline (NA) on leukocyte mobilization.