In vitro expression and inhibition of procoagulant activity produced by bovine alveolar macrophages and peripheral blood cells

Local and systemic activation of coagulation is frequently associated with bacterial sepsis. The coagulopathy is due, at least in part, to expression of tissue factor (TF) by monocytes and macrophages. The purpose of this study was to evaluate the expression of procoagulant activity by bovine alveolar macrophages, leukocytes and platelets, and to determine the relative potency of three chemical inhibitors of TF expression (pentoxifylline, retinoic acid, and cyclosporin A). Bovine alveolar macrophages were stimulated with lipopolysaccharide (LPS) derived from Pasteurella haemolytica or recombinant bovine tumour nervous factor (TNF) and dose- and time-dependent effects on TF expression were studied. LPS and TNF induced TF expression in alveolar macrophages and LPS treatment of whole blood induced TF expression in mononuclear cells. Neutrophils and platelets also expressed procoagulant activity, but this activity was not inhibited by anti-bovine TF monoclonal antibody. Pentoxifylline (40 mol/L), retinoic acid (0.01 mmol/L) and cyclosporin A (0.08 mol/L) inhibited TF expression when added concurrently with LPS or TNF, but not when added 4 h after stimulation. TF mRNA was not detected in unstimulated alveolar macrophages by Northern blot analysis. In contrast, exposure to LPS or TNF for 6 h induced marked expression of TF mRNA, which was inhibited by treatment with pentoxifylline, retinoic acid and cyclosporin A. Expression of TNF by alveolar macrophages stimulated with LPS was also inhibited by these compounds. Our results indicate that procoagulant activity expressed by alveolar macrophages and monocytes is associated with expression of TF, whereas procoagulant activity expressed by neutrophils and platelets is not. The concentrations of pentoxifylline and retinoic acid necessary for inhibition of TF expression in vitro may not be achievable in vivo owing to their toxic effects. However, the in vitro concentration of cyclosporin A that inhibited TF expression did not exceed the plasma concentration observed in humans, and therefore may be useful for inhibition of TF expression in vivo.Abbreviations BAL bronchoalveolar lavage - LPS lipopolysaccharide - cDNA cloned deoxyribonucleic acid - cAMP cyclic adenosine monophosphate - GAPDH glyceraldehyde phosphate dehydrogenase - mRNA messenger ribonucleic acid - TF tissue factor - TNF tumour necrosis factor - DPBS Dulbecco's phosphate-buffered saline     

Cyclosporin: applications in small animal dermatology

Abstract Cyclosporin has been increasingly used for the treatment of skin diseases in small animals. Reported uses include the treatment of atopy, cutaneous lupus erythematosus, feline acquired alopecia resembling pseudopelade of humans, pemphigus erythematosus, pemphigus foliaceus, perianal fistulae and sebaceous adenitis. In addition, cyclosporin has been used anecdotally for several other skin diseases. Few side effects have been noted at doses therapeutic for dermatologic diseases. Current suggestions for monitoring, and the value of trough cyclosporin serum concentrations for prediction of toxicity and efficacy are discussed.     

Inhibition of histamine release from dispersed canine skin mast cells by cyclosporin A, rolipram and salbutamol, but not by dexamethasone or sodium cromoglycate

Despite the important role that canine skin mast cells play in IgE-mediated allergic inflammation, clinically useful compounds for modulating mediator release from these cells or for suppressing cell response are lacking in the dog. The ability of five compounds to inhibit histamine release induced by non immunological (calcium ionophore A23187 and substance P) and IgE-dependent (concanavalin A) stimuli were compared. Sodium cromoglycate, a mast cell stabilizer, and dexamethasone, a glucocorticoid, failed to inhibit histamine release from isolated skin mast cells following any kind of stimulation. Salbutamol, a β-adrenergic agonist, exhibited inhibitory activity (46.0%) only after concanavalin A activation. In contrast, rolipram, a selective phosphodiesterase IV inhibitor and cyclosporin A, an immunosuppressor, showed potent anti allergic actions, inhibiting both IgE-dependent and -independent stimuli. Rolipram inhibited 42.8%, 44.7% and 19.2% of the mediator release induced by ionophore A23187, substance P and concanavalin A, respectively. Similarly cyclosporin A induced 85.9%, 14.9% and 67.3% inhibition after ionophore A23187, substance P and concanavalin A stimulation, respectively. These results suggest that rolipram and cyclosporin A merit to be clinically tested as agents for the treatment of chronic allergic diseases in the dog.     

Presumptive Nocardia spp. infection in a dog treated with cyclosporin and ketoconazole

Abstract

CASE HISTORY: A dog that had received 8 months of cyclosporin and ketoconazole therapy for treatment of atopic dermatitis subsequently developed severe neurological disease, that failed to respond to treatment with trimethoprim-sulphadiazine and clindamycin.

HISTOPATHOLOGICAL FINDINGS: Histopathological examination of the pulmonary parenchyma and spinal cord revealed loose aggregates of Gram-positive, partially acid-fast, fine, beaded, filamentous bacteria, most consistent with Nocardia spp.

DIAGNOSIS: A presumptive diagnosis was made of disseminated nocardiosis of the spinal cord and lungs.

CLINICAL RELEVANCE: Nocardia spp. is an opportunistic actinomycete that may cause disseminated disease, particularly in immunocompromised animals. Cyclosporin is used in veterinary medicine to control immune-mediated and allergic disorders, with few reported adverse side effects. This case gives further evidence that involvement of the spinal cord in nocardiosis of the central nervous system (CNS) carries a poor prognosis, and opportunistic infection by Nocardia spp. may be a potential complication of immunosuppressive cyclosporin therapy in the dog.     

Effects of Cyclosporin A on Blood Pressure, Baroreceptor Reflex and Renal Function in Dogs

The objective of this study is to investigate the effect of cyclosporin A (CsA) on baroreceptor reflex and renal function. Fifteen male mongrel dogs weighing 13-18 kg were divided into three groups and were treated orally as follows: group 1, enalapril 0.5 mg/kg per day for 10 days; group 2, CsA 20 mg/kg per day for 7 days; group 3, enalapril 0.5 mg/kg per day for 3 days combined with CsA 20 mg/kg per day for 7 more days. Measurements of blood pressure and of baroreflex response to sodium nitroprusside (SNP) and phenylephrine (PE) and renal function studies were performed on the days before and after receiving drugs. In group 1, both systolic arterial pressure (SAP) and mean arterial pressure (MAP) were unaltered, while diastolic arterial pressure (DAP) was reduced significantly. In group 2, all pressures (SAP, MAP and DAP) increased significantly. Group 3 showed no change in blood pressure. Studies of baroreceptor reflex showed that only dogs in group 2 had decreased sensitivity to PE without changing the setpoint. No change of the reflex was found in other groups. Renal function studies were unaltered in all groups. The data indicate that CsA increased blood pressure, which may be due to decreased baroreceptor reflex sensitivity mediated via activation of the renin-angiotensin-aldosterone system.     

Pemphigus: current therapy

Pemphigus is an autoimmune skin disease that can present in a variety of forms and can be a challenging disease to manage and treat. An overview of the different forms of pemphigus and diagnostics are discussed including pemphigus foliaceus (PF), pemphigus erythematosus (PE), panepidermal pustular pemphigus (PPP), pemphigus vulgaris (PV) and paraneoplastic pemphigus (PNP). Emphasis on therapy is presented. Included are the most current commonly used therapeutics (glucocorticoids, azathioprine, chlorambucil and tetracycline and niacinamide); current alternative therapeutics (cyclosporin and tacrolimus and mycophenolate mofetil) and additional alternative therapeutics (cyclophosphamide, chrysotherapy, dapsone, sulfasalazine and intravenous immunoglobulin (IVIG) therapy).     

Cyclosporine decreases skin lesions and pruritus in dogs with atopic dermatitis: a blinded randomized prednisolone-controlled trial

During the last decade, oral cyclosporin (CsA) has proven to be effective, in randomized controlled trials, for the treatment of atopic dermatitis (AD) in human patients. The purpose of this blinded randomized controlled trial was to test the hypothesis that CsA was successful in reducing the gravity of clinical signs of AD in dogs. Thirty dogs with nonseasonal AD were randomly allocated to receive an oral solution of either NEORAL CsA (5 mg kg-1) or prednisolone (0.5 mg kg-1) once daily for 6 weeks. Before, and 3 and 6 weeks after therapy, skin lesions were graded by clinicians using the Canine AD Extent and Severity Index (CADESI). Pruritus was assessed by the owners using a visual analog scale (PVAS). In both groups, CADESI and PVAS values were significantly lower at 6 weeks post treatment than before the initiation of therapy (Friedman test, P < 0.0004). The percentage reductions in CADESI and PVAS values from baseline were not statistically different between groups (Mann-Whitney test, P > 0.3). In this experiment, the tolerability and safety of oral CsA and prednisolone appeared similar. One-fifth of dogs given oral CsA occasionally developed diarrhoea or soft stools. One dog that was given CsA developed a generalized papillomatous skin eruption during the second half of the trial. Our study provides randomized controlled trial evidence that CsA reduces the severity of clinical signs in dogs with nonseasonal AD. Moreover, the anti-allergic efficacy of CsA appears comparable with that of prednisolone. We propose that oral CsA should be considered as a valuable alternative to glucocorticoid therapy in dogs with AD.     

鳜亲环蛋白A在传染性脾肾坏死病毒增殖中的作用

为研究鳜亲环蛋白(CypA)在传染性脾肾坏死病毒(ISKNV)感染中的作用,通过RT-PCR克隆了CypA全长开放读码框(SC-CypA)。结果表明SC-CypA基因全长495 bp,编码164个氨基酸,分子量为17.59 ku。通过Blast比对和同源性进化分析,发现其与人、鼠、原鸡和斑点鲖等物种的CypA具有高度相似性,表明SC-CypA属于CypA家族的成员。环孢素A(CsA)具有免疫抑制作用,是CypA的抑制剂。结果发现,CsA浓度与ISKNV增殖具有一定的剂量依赖关系;CsA作用不同时间对ISKNV均有抑制效果;CsA对ISKNV感染诱导的细胞因子的表达具有调节作用,能抑制IL-1β、IL-8、IL-18和ISG15的表达。研究表明,宿主的CypA对ISKNV的增殖起着重要的作用,通过添加其抑制剂CsA能有效抑制病毒的增殖。     

Cyclosporin A metabolism in brown bullhead, Ameriurus nebulosus

Fungi suggested to be used in the control of mosquito larvae produce biologically active cyclopeptides – cyclosporins, which can potentially accumulate in the fish feeding the infected larvae. Whereas toxicity of cyclosporins was observed at the higher doses in man and various experimental animals, the fish tolerated surprisingly high cyclosporin blood levels. Hydroxy-cyclosporins predominated among metabolites excreted into water. In contrast, various N-demethylated cyclosporins created the major part of metabolites identified in the liver and bile. Two new metabolites are described – AM1N and AM6N,10N, which were not so far reported from mammals. Due to the much higher tolerance to cyclosporin, brown bullhead can serve the experimental model to obtain cyclosporin metabolites.