In vitro effects of meloxicam on the number, Foxp3 expression, production of selected cytokines, and apoptosis of bovine CD25+CD4+ and CD25-CD4+ cells

Changes in rabbit lymphocyte subpopulations and activation following long-term administration of meloxicam

Meloxicam is a commonly used analgesic in rabbits. However, its possible impact on lymphocyte subpopulations remained unknown. The aim of the study was to investigate a possible effect of long-term administration of meloxicam on rabbit lymphocyte subpopulations. The study included 8 rabbits given meloxicam orally once daily (1 mg/kg BW) for 14 days and 8 rabbits as a control group. Peripheral blood samples were collected on day 0 (before the first dose of meloxicam), day 3, 7 and 14. Samples were evaluated with a haematology analyser and a flow cytometer. A significant decrease in T: B cell ratio was found in all samples taken during meloxicam administration compared to day 0, as well as in comparison with the control group (P < 0.01). A significant increase (P < 0.05) in proportion of CD5 +CD8 + lymphocytes occurred by day 3. Subsequently, although the values slightly decreased, they still remained elevated throughout all the experiment compared to the values from day 0 (P < 0.05). A slight decrease in T and B cell activation (CD5 +CD25 + and IgM+CD25 +) noticed by day 3, declined during the next days of administration and became more and more significant (finally, P = 0.0078). Since a high significant decrease (P < 0.01) in both T and B cell activation as well as a significant increase (P < 0.05) in CD5 +CD8 + T cells proportion were observed after meloxicam administration, a predicted effect of long-term administration of meloxicam on rabbit lymphocytes was confirmed.

Prostaglandin E2 directly inhibits the conversion of inducible regulatory T cells through EP2 and EP4 receptors via antagonizing TGF-β signalling

Regulatory T (Treg) cells are essential for control of inflammatory processes by suppressing effector T-cell functions. The actions of PGE2 on the development and function of Treg cells, particularly under inflammatory conditions, are debated. In this study, we employed pharmacological and genetic approaches to examine whether PGE2  had a direct action on T cells to modulate de novo differentiation of Treg cells. We found that TGF-β-induced Foxp3 expression and iTreg cell differentiation in vitro is markedly inhibited by PGE2 , which was mediated by the receptors EP2 and EP4. Mechanistically, PGE2 -EP2/EP4 signalling interrupts TGF-β signalling during iTreg differentiation. Moreover, EP4 deficiency in T cells impaired iTreg cell differentiation in vivo. Thus, our results demonstrate that PGE2 negatively regulates iTreg cell differentiation through a direct action on T cells, highlighting the potential for selectively targeting the PGE2 -EP2/EP4 pathway to control T cell-mediated inflammation.

Differential Transcription of Selected Cytokine and Neuroactive Ligand-receptor Genes in Peripheral Leukocytes from Calves in Response to Cautery Disbudding

Simple Summary

Calf disbudding is a painful husbandry practice on dairy and beef cattle farms. Continuing efforts to enhance the accuracy of pain assessment can aid in the application of effective anti-nociceptive (analgesic) agents in non-verbal animals. The aim of this study was to evaluate the changes in the expression of genes involved in inflammation and pain sensitisation in response to removal of horn buds in calves, using hot-iron cauterization. The efficacy of an analgesic, meloxicam, was also tested in attenuating the changes in expression of the studied genes post-disbudding. It was revealed that cautery disbudding induces significant changes in the expression of genes involved in inflammation. Meloxicam was able to blunt the increased expression of some of the genes at 4 h and 24 h after disbudding, while it could not attenuate the increased expression of a few other genes associated with inflammation.

Abstract

Calf disbudding is a painful husbandry practice on dairy and beef cattle farms. An objective measurement of pain is useful to reliably evaluate the pain intensity and anti-nociceptive (analgesic) efficacy of therapeutic agents. The aim of this study was to investigate the changes in peripheral leucocyte inflammatory cytokine gene expression in calves after disbudding, and to assess whether the changes in cytokine gene expression could be an indicator of the efficacy of analgesic drugs. In a randomised controlled study, 16 calves (aged 31 to 41 days and weighing 58 to 73 kg), undergoing routine disbudding, were randomly allocated into two groups (n = 8 in each group). Calves in the control group received no analgesic, while those in the treatment group received 0.5 mg kg⁻¹ meloxicam subcutaneously prior to disbudding. Disbudding was performed using an electric debudder. Blood (10 mL) was sampled from the jugular vein just before and 4 and 24 h post-disbudding, RNA was extracted from leukocytes, and the transcription of 12 genes of interest was assessed using nCounter gene expression assay. The results showed significantly higher transcription (compared to baseline values) of the studied genes (except CRH, IFNγ, and IL10) in the control group calves at either 4 or 24 h post-disbudding. The administration of meloxicam one hour before disbudding significantly attenuated the upregulation of IL6, PGHS2, TAC1, NOS1, and CRH gene transcription post-disbudding, while it did not suppress the elevated transcription of acute and pro-inflammatory cytokines such as IL1β, IFNγ, IL8, and TNFα genes. In conclusion, nCounter gene expression assay seems to be a promising tool to study the expression of cytokine genes and thus could be used for the pre-clinical evaluation of novel analgesics.

Effect of selected non-steroidal anti-inflammatory drugs on activation-induced CD25 expression on murine CD4+ and CD8+ T cells: an in vitro study

The main aim of this study has been to determine the effect of selected non-steroidal anti-inflammatory drugs (NSAIDs) – depending on their selectivity to cyclooxygenase (COX) 1 and 2 – on the activation-induced CD25 expression on CD4⁺ and CD8⁺ T cells. Lymphocytes obtained from lymph nodes of mice were treated with acetylsalicylic acid (ASA; a preferential COX-1 inhibitor), ketoprofen (KET; a non-selective COX inhibitor) and robenacoxib (ROB; a selective COX-2 inhibitor) in concentrations reflecting their plasma levels achieved in vivo at therapeutic doses and in ten-fold lower concentrations. The cells were activated with concanavalin A. In contrast to KET and ROB, ASA had no effect on the activation-induced CD25 expression on CD4⁺ and CD8⁺ T cells, nor did it affect the counts of CD4⁺ and CD8⁺ activated effector (aTeff) and resting (Trest) T cells. Both KET and ROB caused a depletion of CD8⁺ aTeff cells, and additionally KET induced a loss of CD8⁺ Trest cells. Moreover, ROB, but not the other drugs, reduced the activation-induced CD25 expression on CD4⁺ T cells. This suggests that non-selective COX inhibitors and selective COX-2 inhibitors may weaken the effector T cell response by producing a negative effect on the count of aTeff cells. Furthermore, the results seem to imply that ASA and KET have certain potential to induce Foxp3 expression in CD25⁺CD8⁺ and CD25⁺CD4⁺ T cells, respectively. However, all the observed changes were very weakly manifested and therefore it is not certain whether they have clinical importance, despite the statistical significance determined.

Impact of oral meloxicam and long-distance transport on cell-mediated and humoral immune responses in feedlot steers receiving modified live BVDV booster vaccination on arrival

The objective of this study was to investigate the impact of oral meloxicam (MEL) and long-distance transportation on cell-mediated immunity (CMI) in preconditioned steers receiving a booster vaccination on arrival. We hypothesized that steers treated with MEL at 1mg/kg body weight, 6h before night-time transport, would be less immunocompromised on arrival (day 0) and after 7days, and that CMI following vaccination with a modified live bovine viral diarrhea virus (BVDV) recall antigen would be increased. Brahman crossbreed steers, 13-17 months of age (n=87), were randomly assigned to one of four treatment groups: MEL, transported (MTR) (n=22), MEL, non-transported (MNT) (n=22), lactose placebo, transported (CTR) (n=21), and lactose placebo, non-transported (CNT) (n=22). MTR and CTR steers were transported for approximately 16h non-stop on a truck from Mississippi to Iowa (approximately 1300km), whereas steers in the MNT and CNT groups remained in Mississippi as non-transported controls. Body weight was measured and jugular blood was collected at -1, 0, and 7days from all steers at the same time, regardless of location. Multi-parameter flow cytometry (MP-FCM) was used to identify T-cell subsets and detect the expression of three activation markers (CD25 [interleukin (IL)-2 receptor], intracellular interferon-gamma [IFNγ], and IL-4) after in vitro stimulation with BVDV recall antigen. Plasma cortisol concentration was measured on day -1, 0, and 7 as a marker of transport-associated stress. Serum antibody titer to BVDV was assessed on day -1 and day 7 post-booster vaccination. Whole-blood samples were analyzed using MP-FCM on days 0 and 7. Results were log transformed and analyzed using repeated measures of analysis of variance. Compared with non-transported controls, transport led to an increase in BVDV-induced expression of CD25, IFNγ, and IL-4 in CD4(+), CD8(+), and γδ(+) T-cell subsets (P<0.05). MEL treatment mitigated the transportation-associated increase in CD25 expression by peripheral blood mononuclear cells (PBMCs), CD4(+), and γδ(+) T cells. CMI outputs for the MTR group were less than those of the CTR group (P<0.05); however, the MTR and NT groups did not differ (P>0.10). A treatment*transport interaction was noted for the increase in IL-4 expression by CD8(+) T cells after transport, with a significant difference between the CTR and MTR groups at day 7. In conclusion, the use of oral MEL prior to transport appears to have inhibitory or homeostatic effects, but further research is needed to validate the effect of MEL treatment on specific T-cell subsets in transported cattle.

Enhanced analgesic activity by cyclodextrins - a systematic review and meta-analysis

INTRODUCTION

Analgesics can be ineffective in treating some types of pain, hence, improved drug delivery systems could optimize their efficacy.

AREA COVERED

The authors conducted a systematic review to evaluate the analgesic activity of compounds complexed in cyclodextrins, analyzing whether these complexes improved analgesic efficacy. The search terms 'analgesics', 'cyclodextrins' and 'drug effects' were used to retrieve articles in SCOPUS, PUBMED and EMBASE. A total of 22 papers were identified. In the clinical studies, there was greater efficacy in the complexed drug when compared with control groups, with differences ranging from 25 to 83%. Through a meta-analysis, the preclinical studies showed that the complexed drug had a significantly (p < 0.01) greater effect than the non-complexed drug.

EXPERT OPINION

The use of cyclodextrins can improve the efficacy of analgesic compounds, and they are an important tool in the search for greater analgesic effect. They may also be a way to reduce the therapeutic doses, and hence increasing the potential of the drug.

Prostaglandin E2 inhibits IL-10 production by bovine CD4+ T cells

Although prostaglandin E2 (PGE2) is a pro-inflammatory mediator, it also produces some effect which is anti-inflammatory in character. It is suggested that one of the mechanisms responsible for the latter effect is the increased synthesis of IL-10. The aim of this study has been to determine the influence of PGE2 on IL-10 production by bovine CD4+ and CD8+ T cells and NK cells. With this aim, peripheral blood mononuclear cells collected from 12-month-old heifers (n = 10) were treated without or with PGE2 (10(-6) M). Flow cytometric analysis showed that PGE2 caused a reduction in the percentage of IL-10 producing CD4+ T cells (P < 0.001), while leaving the secretion of this cytokine by CD8+ T cells and NK cells unaffected. This seems to indicate that PGE2 in cattle does not produce an anti-inflammatory effect by increasing the synthesis of IL-10; contrary to this, it may aggravate an inflammatory response by inhibiting the secretion of this cytokine by CD4+ T cells.

Prostaglandin E₂ down-regulates the expression of CD25 on bovine T cells, and this effect is mediated through the EP4 receptor

A crucial event in the initiation of an immune response is the activation of T cells, which requires IL-2 binding to its high-affinity IL-2 receptor for optimal signaling. The IL-2 receptor α-chain (CD25) is needed for the high affinity binding of IL-2 to effector cells and is potently induced after T cell activation. The aim of this research has been to determine whether prostaglandin E2 (PGE2) affects the CD25 expression on bovine T cells, and if it does, then which of the PGE2 receptor (EP) subtype(s) mediate(s) this effect. Herein, we report that exposure of peripheral blood mononuclear cells (PBMC) to PGE2 considerably reduces the percentage and absolute counts of CD25(+)CD4(+), CD25(+)CD8(+) and CD25(+)WC1(+) T cells, significantly increases the value of these parameters with respect of CD25(-)CD4(+), CD25(-)CD8(+) and CD25(-)WC1(+) T cells, and does not affect counts of the total populations of CD4(+), CD8(+) and WC1(+) T cells. These results indicate that PGE2 down-regulates the CD25 expression on bovine T cells. Moreover, we show that the selective blockade of EP4 receptor, but not EP1 and EP3 receptors, prevents this effect. Interestingly, the exposure of PBMC to a selective EP2 receptor agonist leads to a substantial increase in the percentage and absolute number of CD25(+)CD4(+), CD25(+)CD8(+) and CD25(+)WC1(+) T cells. In conclusions, the PGE2-induced down-regulation of CD25 expression on bovine CD4(+), CD8(+) and WC1(+) T cells should be considered as immunosuppressive and anti-inflammatory action, because these lymphocytes primarily represent effector cells and adequate CD25 expression is essential for their correct functioning. The PGE2-mediated down-regulation of the CD25 expression on bovine T cells is mediated via the EP4 receptor, although selective activation of the EP2 receptor up-regulates the CD25 expression on these cells. Thus, with respect to the effect of PGE2 on the CD25 expression on bovine T cells, EP4 receptor serves as an inhibitory receptor, whereas EP2 receptor functions as a stimulatory receptor. The fact that non-selective stimulation of EP receptors, i.e. triggered by PGE2, leads to weaker CD25 expression proves that inhibitory actions prevail over stimulatory ones. These results indicate the possibility of pharmacological manipulation of the CD25 expression on T cells via selective antagonists and agonists of EP2 and EP4 receptors.

Neutrophil and macrophage apoptosis in bronchoalveolar lavage fluid from healthy horses and horses with recurrent airway obstruction (RAO)

BACKGROUND

Dysregulation of apoptosis has been implicated in a range of diseases including tumors, neurodegenerative and autoimmune diseases, as well as allergic asthma and chronic obstructive pulmonary disease (COPD) in humans. Although it has a different pathophysiology, delayed apoptosis of various inflammatory cells may play a pivotal role in the development of recurrent airway obstruction (RAO) in horses. Reduction of inflammatory cell apoptosis or a dysregulation of this process could lead to chronic inflammation and tissue injury. Therefore, the aim of this study was to investigate the rate of apoptosis and necrosis of neutrophils and macrophages in bronchoalveolar lavage fluid obtained from seven horses suffering from RAO (study group) and seven control horses.

RESULTS

We demonstrated that neutrophil/macrophage apoptosis is altered in RAO-affected horses compared with the control group in the BAL fluid. We found a significant difference between the median percentage of early and late apoptosis of neutrophils between the study and control group of horses. Moreover, we found a positive correlation between the rate of apoptosis and the median percentage of macrophages in RAO-affected horses.

CONCLUSION

The findings suggest that apoptosis dysregulation may play a significant role in the pathogenesis of RAO. However, further studies are needed to clarify the role of altered apoptosis in the course of equine recurrent airway obstruction.

In vitro studies on the influence of dexamethasone and meloxicam on bovine WC1+ γδ T cells

In view of the lack of data on the effect of meloxicam (non-steroidal anti-inflammatory drug) on bovine γδ T cells (WC1(+) cells) and very poorly recognized effects of dexamethasone (steroidal anti-inflammatory drug) on these cells, the purpose of the present study has been to determine the in vitro influence of these drugs on CD25(high)WC1(+), CD25(low)WC1(+) and CD25(-)WC1(+) lymphocytes of the peripheral blood of cattle. Peripheral blood mononuclear cells were treated with the drugs in concentrations reflecting their plasma levels achieved in vivo at therapeutic doses (dexamethasone 10(-7)M; meloxicam 5×10(-6)M) and at ten-fold lower concentrations. It was found out that percentages and absolute counts of CD25(high)WC1(+) and CD25(low)WC1(+) cells increased in the presence of dexamethasone, and this effect was at least partly attributable to lower mortality of these cells, whose apoptosis was depressed by exposure to dexamethasone. It seems certain that this effect was not a result of increased multiplication of CD25(high)WC1(+) and CD25(low)WC1(+) cells because their proliferation was reduced in the presence of dexamethasone. Exposure to this drug caused a rapidly occurring and lasting depletion of CD25(-)WC1(+), which was at least partly due to their higher apoptosis. The results seem to suggest that impaired proliferation of these cells was responsible for a more profound expression of this disorder. Paradoxically, the percentage of cells producing IFN-γ, a proinflammatory cytokine, increased in the presence of dexamethasone, whereas the count of cells secreting the key anti-inflammatory and immunosuppressive cytokine, i.e. IL-10, declined. This effect was observed in all analyzed subpopulations of cells. Meloxicam did not interfere so drastically as dexamethasone with the functioning of WC1(+) lymphocytes because it did not affect their apoptosis, proliferation, percentage or absolute count. With respect to the effect of meloxicam on counts of particular WC1(+) lymphocyte subpopulations, it was only demonstrated that exposure to the drug was correlated with a transient and very weakly expressed decrease in the relative and absolute counts of CD25(high)WC1(+) and CD25(low)WC1(+) cells, which was most probably a result of a temporary down-regulation of the expression of the CD25 molecule. In the presence of meloxicam, percentages of IFN-γ(+)CD25(-)WC1(+) cells as well as cells producing IL-10 declined, an effect observed in all analyzed cell populations. These results suggest that care should be taken when administering this medication to animals with bacterial or viral infections, and we should avoid giving it to patients suffering from allergic or autoimmune disorders.