Effect of ciclosporin and methylprednisolone acetate on cats previously infected with feline herpesvirus 1

Pharmacology of drugs used in autoimmune dermatopathies in cats and dogs: A narrative review

Immunosuppressive drugs are the mainstay of treatment for many feline and canine autoimmune skin diseases, either as monotherapy or in combination with other drugs. Treatment with these drugs is often lifelong and may have long-term consequences on the affected animal's overall quality-of-life. Clinicians need to understand the pharmacology of immunosuppressants in planning and executing the treatment regimen for the best possible clinical outcome, as well as reducing the risk of adverse effects. This review paper will focus on the mechanism of action, pharmacokinetics and pharmacodynamics, clinical uses and adverse effects of immunosuppressive drugs used to treat autoimmune dermatoses in cats and dogs. These include glucocorticoids, ciclosporin A, azathioprine, chlorambucil, mycophenolate mofetil, oclacitinib and Bruton's tyrosine kinase inhibitors.

Feline herpesvirus-1-related multiple respiratory eosinophilic nodules in an adult cat receiving long-term oral prednisolone

Case summary

A 10-year-old male castrated domestic shorthair cat was presented for evaluation of a 3-day history of increased inspiratory effort. The cat had received prednisolone 1 mg/kg PO q24h for 1 year due to chronic diarrhea. On physical examination, the patient exhibited severe stridor, intermittent open-mouth breathing and bilateral mucopurulent nasal discharge. Subcutaneous emphysema was palpated over the dorsal cervical region. Mild hypoventilation (PvCO2 55.1 mmHg; approximate reference interval 35-45 mmHg) was identified. Cervicothoracic radiographs showed marked gas tracking within cervical soft tissues with concurrent laryngeal thickening, pulmonary nodules, a bronchial pulmonary pattern, pneumomediastinum and aerophagia. The cat was hospitalized and treated overnight with oxygen and intravenous fluid therapy before anesthesia the next day. On laryngoscopy, a large tracheal mass was observed arising from the right subglottic region and was removed using biopsy forceps. CT revealed an additional mass at the level of the tracheal bifurcation causing marked luminal narrowing of the trachea and proximal main bronchi. The cat made a good initial recovery, although moderate stridor persisted. Five days later, the cat was re-examined due to recurrence of respiratory distress and orthopnea, and the owner elected euthanasia. Histopathology revealed severe nodular obstructive eosinophilic plasmacytic laryngotracheitis with intranuclear inclusion bodies positive for feline herpesvirus-1 on immunohistochemistry.

Relevance and novel information

This report describes the presentation and management of a cat with respiratory distress secondary to intratracheal eosinophilic masses caused by feline herpesvirus-1. Although the outcome was ultimately unsatisfactory, to the authors' knowledge, this clinical presentation has not been previously reported.

Is methylprednisolone acetate-related insulin resistance preventable in cats?

Methylprednisolone acetate (MPA) is often prescribed to cats despite being recognized eventually as diabetogenic. To assess MPA-related insulin resistance and evaluate the efficacy of metformin or an obesity and diabetes mellitus (O&D) adjuvant diet as protective factors, a randomized clinical trial was conducted with 28 owned cats undergoing glucocorticoid therapy. A single MPA dose of 20 mg intramuscularly was administered to each cat. Controls (n=10) received only MPA. In the diet group (n=9), replacement of their habitual diet by ad-libitum feeding of a feline commercial O&D diet (Equilíbrio O&D, Total Alimentos ADM) was made. In the metformin group (n=9), metformin chlorhydrate 25mg/cat PO/q24h was administered for 30 days. All patients were clinically evaluated at baseline (T0), day 15 (T15), and day 30 (T30) and blood draw for complete blood count, serum biochemistry, and determination of insulin concentrations. Fasting Insulin Sensitivity Index (SI), Amended Insulin to Glucose Ratio (AIGR), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and Homeostatic Model Assessment of beta-cell function (HOMA-B) were calculated based on fasting glycemia and insulinemia. All groups showed significantly higher levels (p < 0.05) of neutrophils, albumin, glucose, cholesterol, triglycerides, and serum insulin at T15. Patients in the metformin group showed also higher SI, AIGR, and HOMA-IR results at T15. Also, at T15, reduced levels (p < 0.05) of eosinophils, lymphocytes, and creatinine were documented in all groups. An MPA single dose induced changes in insulin sensitivity in cats; however, neither metformin nor O&D feeding used in this study was effective as protective factors against MPA-related insulin resistance.

Evaluation of liposome toll-like receptor ligand complexes for non-specific mucosal immunoprotection from feline herpesvirus-1 infection

Background

Feline herpesvirus‐1 (FHV‐1) infection can result in serious morbidity and mortality, especially in kittens. Immunotherapy using liposome‐toll‐like receptor (TLR) ligand complexes (LTC) has been shown to activate innate immune responses.

Objectives

To determine in kittens whether mucosal administration of LTC before FHV‐1 inoculation would decrease severity of clinical signs and decrease quantities of FHV‐1 DNA in materials collected on oropharyngeal swabs.

Animals

Nineteen, 14‐week‐old, purpose‐bred kittens.

Methods

Pilot clinical trial with 2 groups of kittens allocated to either an LTC or control group. The LTC were administered into both nares and the oropharynx of the 12 LTC group kittens, and all 19 kittens were inoculated with FHV‐1 24 hours later. Clinical scores were determined daily for 28 days, and oropharyngeal mucosal materials were collected every 7 days to assess FHV‐1 DNA quantities for comparison between groups.

Results

Conjunctivitis was more common in kittens in the control group on Days 15‐28 (P = .01) and Days 1‐28 (P = .02). Total respiratory scores were higher in the LTC group on days 15‐28 (P = .03). The LTC group had significantly decreased FHV‐1 DNA on swabs when compared to the control group on some postinoculation days, using 2 methods of calculation.

Conclusions and Clinical Importance

Administration of LTC to kittens was shown to decrease FHV‐1 DNA and some manifestations of illness in kittens when administrated 24 hours before inoculation, suggesting clinical benefit.

Atopic dermatitis in cats and dogs: a difficult disease for animals and owners

The purpose of this review article is to give an overview of atopic dermatitis in companion animals and of recent developments including knowledge on immunological background, novel treatment options and difficulties in disease management. The prevalence of hypersensitivities seems to be increasing. The pathogenetic mechanisms are not fully understood, yet multiple gene abnormalities and altered immunological processes are involved. In dogs and cats, the diagnosis of atopic dermatitis is based on history, clinical examination and exclusion of other differential diagnoses. Intradermal testing or testing for serum allergen-specific Immunoglobulin E is only used to identify allergens for inclusion in the extract for allergen immunotherapy. Symptomatic therapy includes glucocorticoids, ciclosporin, essential fatty acids and antihistamines. A selective janus kinase 1 inhibitor and a caninized monoclonal interleukin-31 antibody are the newest options for symptomatic treatment, although longterm effects still need to be assessed. The chronic and often severe nature of the disease, the costly diagnostic workup, frequent clinical flares and lifelong treatment are challenging for owners, pets and veterinarians. Patience and excellent communication skills are needed to achieve a good owner compliance and satisfactory clinical outcome for the animal.

Ciclosporin and the cat: Current understanding and review of clinical use

Practical relevance: Ciclosporin (CsA) is a systemic immuno-modulatory drug widely used to treat immune-mediated diseases in humans and veterinary species. CsA was registered for use in cats in the USA and Europe in 2011, and is indicated for the treatment of chronic allergic dermatitis at a recommended daily dose of 7 mg/kg PO.

AUDIENCE

This review will be of interest to all veterinarians working with cats, given the wide range of potential applications of CsA and its safety profile. Although the drug is currently only licensed to treat chronic allergic dermatitis in cats, a small number of reports describe its use in non-dermatological conditions. Evidence base: This article reviews the mechanism of action, pharmacokinetics, drug interactions, adverse effects and clinical use of CsA, both for the licensed indication and for off-label use in the feline patient. Information presented has been summarised from the existing literature on CsA, with specific interest in studies carried out in cats. For its licensed indication, chronic allergic dermatitis, evidence provided includes randomised, placebo or prednisolone-controlled studies (EBM grade I) and prospective or retrospective open trials.