Maria Ignez Capella Gaspar Elsas

Upregulation by glucocorticoids of responses to eosinopoietic cytokines in bone-marrow from normal and allergic mice

Since the production of eosinopoietic cytokines (GM‐CSF, IL‐3, IL‐5) is inhibited by glucocorticoids, while responsiveness to these cytokines is enhanced in bone‐marrow of allergic mice, we studied the ability of glucocorticoids to modulate murine bone‐marrow eosinopoiesis. Progenitor (semi‐solid) and/or precursor (liquid) cultures were established from bone‐marrow of: (a) normal mice; (b) ovalbumin‐sensitized and challenged mice or (c) dexamethasone (1–5 mg kg−1) injected mice. Cultures were established with GM‐CSF (2 ng ml−1) or IL‐5 (1 ng ml−1), respectively, alone or associated with dexamethasone, hydrocortisone or corticosterone. Total myeloid colony numbers, frequency and size of eosinophil colonies, and numbers of eosinophil‐peroxidase‐positive cells were determined at day 7. In BALB/c mice, dexamethasone (10−7 M) increased GM‐CSF‐stimulated myeloid colony formation (P=0.01), as well as the frequency (P=0.01) and size (P<0.01) of eosinophil colonies. Dexamethasone (10−7 M) alone had no effect. Dexamethasone (10−7–10−10 M) increased (P<0.002) eosinophil precursor responses to IL‐5. Potentiation by dexamethasone was still detectable: (a) on low density, immature, nonadherent BALB/c bone‐marrow cells, (b) on bone‐marrow from other strains, and (c) on cells from allergic mice. Hydrocortisone and corticosterone had similar effects. Dexamethasone administered in vivo, 24 h before bone‐marrow harvest, increased subsequent progenitor responses to GM‐CSF (P=0.001) and precursor responses to IL‐5 (P<0.001). These effects were blocked by RU 486 (20 mg kg−1, orally, 2 h before dexamethasone, or added in vitro at 10 μM, P<0.001). Glucocorticoids, acting in vivo or in vitro, through glucocorticoid receptors, enhance bone‐marrow eosinopoiesis in naïve and allergic mice.

Impact of diet on the immunological microenvironment of the pregnant uterus and its relationship to allergic disease in the offspring: a review of the recent literature

Medical progress has reduced the mortality from infectious diseases in most countries, but allergic diseases have become more prevalent worldwide over the same period, especially in industrialized countries. This has prompted speculation that modern lifestyles have altered the relationship between heredity and environment so as to promote development of an atopic phenotype when exposure to infection decreases. A healthy uterine microenvironment is known to favor Th2 lymphocyte development. However, some evidence suggests that persistence of the Th2 pattern of immunity directs the developing organisms immune response towards a long-lasting atopic phenotype. Even though the outcome also depends on other factors (such as infection, functional state of the intestinal microflora, and exposure to environmental allergens at times critical to development), it seems that the immune system during the perinatal period is responsive to interventions that are no longer effective in adulthood. We have reviewed the literature accessible through Medline to identify recent advances in the prevention of allergic disease through interventions in the fetal-maternal relationship. Diet seems to have a significant impact on the immunological profile of the pregnant uterus, as well as on the postnatal development of allergic disease in the offspring, as suggested by the effects of probiotic bacteria and by manipulations of the dietary content of polyunsaturated fatty acids and antioxidants. This highlights the need for further studies, in order to define the best intervention methods, the most appropriate time interval and the individuals who will most likely benefit from them.

Induction of bone‐marrow eosinophilia in mice submitted to surgery is dependent on stress‐induced secretion of glucocorticoids

We examined bone‐marrow in mice receiving subcutaneous implants of heat‐coagulated egg white, which are known to present chronic eosinophilic inflammation at the implant site. Egg white implants (EWIs) induced marked bone‐marrow eosinophilia, and increased bone‐marrow cell responses to granulocyte‐macrophage colony‐stimulating factor and interleukin‐5 in culture. These effects were observed as early as 24 h and lasted for, at least, 30 days in implant recipients. We found, however, that increased eosinophil production was also observed in control mice which underwent surgery but received no EWI (sham‐implanted mice), up to 15 days post‐surgery. As this suggests an important contribution of nonspecific stress mechanisms to eosinopoiesis, we further evaluated the role of stress hormones produced by the adrenal glands in the bone‐marrow eosinophilia of sham‐implanted mice. Bone‐marrow eosinophilia in mice undergoing surgery was dissociated from increases in other haemopoietic lineages. Surgery by itself increased circulating corticosterone levels by 24 h, and the increase was prevented by inhibition of adrenal glucocorticoid production by metyrapone. The effect of surgery on bone‐marrow eosinophilia was prevented by pretreatment with both the glucocorticoid receptor antagonist, mifepristone, and metyrapone, and by surgical adrenalectomy. By contrast, cathecolamine receptor antagonists (propranolol, prazosin and yohimbine) were ineffective, indicating that cathecolamine release from the adrenal glands was not responsible for the effects on bone‐marrow. These results highlight a critical role for stress‐induced glucocorticoid hormones in selectively upregulating bone‐marrow eosinopoiesis in mice submitted to surgery.

Cysteinyl leukotrienes mediate the enhancing effects of indomethacin and aspirin on eosinophil production in murine bone marrow cultures

Prostaglandin E2 (PGE2) suppresses, while indomethacin and aspirin enhance, eosinophil production in murine liquid bone‐marrow cultures. Because cysteinyl leukotrienes (cys‐LTs) enhance human eosinophil colony formation, we investigated whether the effects of indomethacin and aspirin on murine bone‐marrow were due to blockade of PGE2 production alone, or involved further promotion of cys‐LTs production/signalling.

Murine myeloid progenitor responses to GM-CSF and eosinophil precursor responses to IL-5 represent distinct targets for downmodulation by prostaglandin E2

Because Prostaglandin E2 (PGE2) and dibutiryl cyclic AMP (dbcAMP) modulate the production and effects of haemopoietic cytokines in allergy, we examined their ability to modulate responses of myeloid progenitors to GM‐CSF, and of eosinophil precursors to IL‐5. The ability of PGE2, dbcAMP, rolipram, forskolin, dbcGMP and PGD2, to modulate the responses to GM‐CSF and IL‐5 in colony formation (progenitor) and eosinophil differentiation (precursor) assays using bone‐marrow from nonsensitized or from intranasally‐challenged, ovalbumin‐sensitized mice of five strains was studied. PGE2 (10−7 M) inhibited GM‐CSF‐stimulated colony formation in bone‐marrow from BP‐2 mice. This effect was duplicated by dbcAMP (0.3–1×10−6 M), Rolipram (10−5 M) and forskolin (3×10−5 M), but not Prostaglandin D2 (10−6 M). Inhibition affected similarly all myeloid colony types. Progenitors from sensitized and challenged BP‐2 mice were also inhibited by PGE2 and cyclic AMP. PGE2 inhibited progenitors from C57BL/10, CBA/J and A/J, but not BALB/c mice. However, BALB/c progenitors were sensitive to dbcAMP and Forskolin (10−4 M). In contrast, in precursor assays, PGE2 (10−7–10−9 M) blocked responses to IL‐5 in bone‐marrow from BP‐2 and BALB/c mice, either naïve or sensitized and challenged, to a similar extent. PGD2 (10−6 M) was ineffective, as was PGE2 (10−7 M), if added after 48 h of culture. In conclusion, PGE2 inhibits the responses of bone‐marrow myeloid progenitors to GM‐CSF and of eosinophil precursors to IL‐5, in naïve or ovalbumin sensitized and challenged mice. These effects are duplicated by cyclic AMP‐elevating agents. In the BALB/c strain, the resistance of progenitors, but not precursors, to PGE2 inhibition, indicates these developmental stages are separate targets for PGE2 modulation.

Associação entre ângulo de fase, PRISM I e gravidade da sepse

BACKGROUND AND OBJECTIVES: Phase angle (PA) is the difference between voltage and current and can be used as an indicator of body cell mass. Clinical studies show that low phase angle is associated with morbidity and mortality of critical patients. The purpose of this study was to know the relation between phase angle and the Pediatric Risk of Mortality I (PRISM I) score, associating this score with the severity of sepsis. METHODS: A transversal study was performed at the Pediatric Intensive Care Unit (PICU) in Instituto Fernandes Figueira. The patients were classified according to age, gender, sepsis severity, cause of respiratory failure, PRISM I score, multiple organ dysfunction syndromes (MODS). Electrical bioimpedance analysis (BIA) was performed in all patients. Phase angle was calculated directly from reactance (Xc) and resistance (R). AF = arc-tangent reactance/resistance x 180o/Pi. RESULTS: 75 patients (68 septic) were evaluated. The incidence of septic shock was 39.7%, severe sepsis 42.6% and sepsis 17.6%. There was no significative statistical difference between the mean values of BIA and the categories of PRISM I, MODS, or the length of stay the PICU. The PAs lowest values (1.5o-2.2o) were associated to the greatest PRISMs scores (> 30%). CONCLUSIONS: Pediatric critical patients show low phase angle values, which might have prognostic implication.

Isolation and Characterization of Hemopoietic Cells From Lungs of Allergic Mice

We developed a procedure for the isolation of hemopoietic cells from murine lung. Ovalbumin sensitization and challenge increased the numbers of functionally intact hemopoietic progenitors recovered from digested lung fragments by 80-fold to 120-fold, relative to naive controls. Eosinophil precursors, which are absent in the naive mouse lung, accumulated in the lungs of sensitized/challenged mice. Progenitors in allergic BALB/c mice were recoverable from lung parenchyma, not blood or airways, and were exclusively CD34+. Precursors isolated from allergic lung, unlike those from bone marrow, were inhibited by dexamethasone and were stimulated by prostaglandin D(2). This directly demonstrates that sensitized/challenged lungs accumulate hemopoietic progenitors and precursors, distinct from those in bone marrow.

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

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. 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. 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. 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.

Do glucocorticoids enhance eosinopoiesis

, in which tissue in-filtration by eosinophil leukocytes playsa major role in pathogenesis. Eosinophilsare produced and stored in the bonemarrow, to be subsequently released intothe circulation and recruited, under theinfluence of chemotactic factors, into in-flammatory sites, where they can contri-bute to tissue damage by secreting toxicproteins, inflammatory mediators andcytokines

Profile of Kawasaki disease in children referred to two pediatric rheumatology services in Rio de Janeiro, Brazil

OBJECTIVES To describe a population of children diagnosed with Kawasakis disease (KD) in pediatric rheumatology centers of Rio de Janeiro, Brazil, defining the magnitude of the delay period in diagnosing KD and initiating treatment due to confusion with common childhood febrile illnesses and the impact of this delay on the frequency of coronary sequels. METHODS Data analysis from hospital records summarized in a dedicated form, including name, gender, age, date of first recorded clinical signs, date of admission to the specialty service, information about symptoms, clinical evolution, intravenous immunoglobulin (IVIG) use and coronary sequels. RESULTS Of 125 patients, 63% were males. 40% were under 2 years at diagnosis. Average lapse between earliest signs and KD diagnosis was 12 days (mean fever duration, 14 d). Only 22.4% had a diagnosis of KD before entering the specialty service. For the remainder, initial hipotheses included: bacterial (60%) and viral infections (12%), rheumatological diseases (4%) and adverse vaccination reactions (1.6%). Hence, prevalent febrile illnesses of childhood were major confounding factors. For records (85.6%) mentioning treatment, 46.7% reported IVIG treatment, beginning after day 10 in 23 cases (21.5%). 20 patients (16%) presented coronary sequels, 9 of which were diagnosed late, including 3 given IVIG after day 10, and 6 given no IVIG. We found no significant association between the frequency of coronary sequels and: a) sex; b) age; c) clinical criteria; d) initiation of IVIG treatment (before or after day 10). CONCLUSIONS Common febrile illnesses of childhood often confound the diagnosis of KD.