Oral Bromelain Attenuates Inflammation in an Ovalbumin-induced Murine Model of Asthma

Bromelain, a widely used pineapple extract with cysteine protease activity, has been shown to have immunomodulatory effects in a variety of immune system models. The purpose of the present study was to determine the effects of orally administered bromelain in an ovalbumin (OVA)-induced murine model of acute allergic airway disease (AAD). To establish AAD, female C57BL/6J mice were sensitized with intraperitoneal (i.p.) OVA/alum and then challenged with OVA aerosols for 3 days. Mice were gavaged with either (phosphate buffered saline)PBS or 200 mg/kg bromelain in PBS, twice daily for four consecutive days, beginning 1 day prior to OVA aerosol challenge. Airway reactivity and methacholine sensitivity, bronchoalveolar lavage (BAL) cellular differential, Th2 cytokines IL-5 and IL-13, and lung histology were compared between treatment groups. Oral bromelain-treatment of AAD mice demonstrated therapeutic efficacy as evidenced by decreased methacholine sensitivity (P ≤ 0.01), reduction in BAL eosinophils (P ≤ 0.02) and IL-13 concentrations (P ≤ 0.04) as compared with PBS controls. In addition, oral bromelain significantly reduced BAL CD19+ B cells (P ≤ 0.0001) and CD8+ T cells (P ≤ 0.0001) in AAD mice when compared with controls. These results suggest that oral treatment with bromelain had a beneficial therapeutic effect in this murine model of asthma and bromelain may also be effective in human conditions

Bromelain Inhibits Allergic Sensitization and Murine Asthma via Modulation of Dendritic Cells

The incidence of atopic conditions has increased in industrialized countries. Persisting symptoms and concern for drug side-effects lead patients toward adjunctive treatments such as phytotherapy. Previously, we have shown that Bromelain (sBr), a mixture of cysteine proteases from pineapple, Ananas comosus, inhibits ovalbumin (OVA)-induced murine model of allergic airway disease (AAD). However, sBr’s effect on development of AAD when treatment is administered throughout OVA-alum sensitization was unknown and is the aim of the present study. C57BL/6J mice were sensitized with OVA/alum and challenged with 7 days OVA aerosol. sBr 6 mg/kg/0.5 ml or PBS vehicle were administered throughout sensitization. Lung, bronchoalveolar lavage (BAL), spleen, and lymph nodes were processed for flow cytometry and OVA-specific IgE was determined via ELISA. sBr treatment throughout OVA-alum sensitization significantly reduced the development of AAD (BAL eosinophils and lymphocytes). OVA-specific IgE and OVA TET+ cells were decreased. sBr reduced CD11c+ dendritic cell subsets, and in vitro treatment of DCs significantly reduced CD44, a key receptor in both cell trafficking and activation. sBr was shown to reduce allergic sensitization and the generation of AAD upon antigen challenge. These results provide additional insight into sBr's anti-inflammatory and antiallergic properties and rationale for translation into the clinical arena

Rate-limiting steps in the interactions of fluoropyrimidines and methotrexate

Rate-limiting steps are defined between methotrexate (MTX) and 5-fluorouracil (FU) or 5-fluorodeoxyuridine (FUdR) and [14C]-formate incorporation into RNA, DNA and protein as a function of the basal rate of dTMP synthesis. When Ehrlich cells are incubated with 0.1 μM FUdR, 1 μM FU and 50 μM MTX for 1-35 min, [3H]-deoxyuridine (UdR) incorporation into DNA is maximally inhibited within 1, 10 and 15 min respectively. The delay in suppression of [3H]-UdR incorporation into MTX-exposed cells compared to cells exposed to FU or FUdR is related to the slow transport of MTX and the increasing free intracellular MTX levels. Influx of MTX is 4 and 10 times slower than FU and FUdR respectively. At 2.5, 5, 10 and 15 min the free intracellular MTX levels (nmol/g dry wt) are 5.8, 7.4, 8.7 and 8.8 respectively. Free intracellular FdUMP is identified 1 min after exposure of cells to FU and FUdR. Antagonism to MTX-suppression of [14C]-formate incorporation into RNA, DNA and protein occurs when cells are simultaneously exposed to MTX and FU or FUdR. However, [14C]-formate incorporation into RNA, DNA and protein is maximally inhibited when Ehrlich tumor cells are incubated with 50 μM MTX for 10 min and then exposed to 1 μM FU for 1 min (a time in which free intracellular MTX is maximal and [3H]-UdR incorporation is maximally suppressed). Hence the sequence and time of administration of FU or FUdR and MTX inhibition of formate incorporation into RNA, DNA and protein is related to the rate of (a) FU, FUdR and MTX transport, (b) FU and FUdR metabolism to FdUMP and (c) generation of maximal free intracellular MTX. © 1984

Subcutaneous Late Phase Responses are Augmented During Local Inhalational Tolerance in a Murine Asthma Model

Acute exposure of sensitized mice to antigen elicits allergic airway disease (AAD) characterized by Th2 cytokine-dependent pulmonary eosinophilia, methacholine hyperresponsiveness and antigen-specific IgE elevation. However, chronic exposure induces a local inhalational tolerance (LIT), with resolution of the airway responses but persistent systemic IgE production. To further determine if systemic immunologic responses were maintained during LIT, we assessed subcutaneous late phase responses to ovalbumin in this model. Sensitized and AAD mice developed small subcutaneous responses to ovalbumin, with footpad thickness increasing to 113.7 and 113.6% of baseline, respectively. In comparison, LIT mice developed marked foot swelling (141.6%). Histologic examination confirmed increased inflammation in the chronic animals, with a significant contribution by eosinophils. Thus, the resolution of airway inflammatory responses with chronic antigen inhalation is a localized response, not associated with loss of systemic responses to antigen