Immunohistochemical Characterization of Oral Mucosal Lesions in Cats with Chronic Gingivostomatitis

CATastrophic myths part 2: Common misconceptions about the environmental, nutritional, and genetic management of domestic cats and their welfare implications

Despite the cat's popularity as a companion species, many owners and practitioners lack high quality information about important aspects of their behavior and management. Myths, anecdotes, and narratives of cats as 'low maintenance, self-sufficient' animals are pervasive, and the degree to which these may underlie complacency about fully meeting cats' needs is unknown. Several studies suggest that cat welfare and the human-cat bond may benefit from improved education about how to optimize the domestic cat's management and husbandry needs in homes and elsewhere. This paper is the second of a two-part series addressing common myths about cats. The purpose of this paper is to review and debunk common misconceptions about optimal cat care, feeding behavior, genetics, and training. Replacing these misconceptions with scientifically generated information could have a significant impact on the behavioral management of cats, positively influencing their physical health, mental stimulation, and well-being, and reducing stress for both cats and the people caring for them. Areas where further research is required to address ambiguities, and to better meet cats' needs in homes and other environments, are also identified.

Transcriptomic signatures of feline chronic gingivostomatitis are influenced by upregulated IL6

Feline chronic gingivostomatitis (FCGS) is a relatively common and debilitating disease characterized by bilateral inflammation and ulceration of the caudal oral mucosa, alveolar and buccal mucosa, and varying degrees of periodontal disease. The etiopathogenesis of FCGS remains unresolved. In this study, we performed bulk RNA-seq molecular profiling of affected tissues derived from a cohort of client-owned cats with FCGS compared to tissues from unaffected animals, to identify candidate genes and pathways that can help guide future exploration of novel clinical solutions. We complemented transcriptomic findings with immunohistochemistry and in situ hybridization assays to better understand the biological significance of the results and performed RNA-seq validation of biologically relevant differentially expressed genes using qPCR assays to demonstrate technical reproducibility. Transcriptomic profiles of oral mucosal tissues in cats with FCGS are enriched with immune- and inflammation-related genes and pathways that appear to be largely influenced by IL6, and include NFKB, JAK/STAT, IL-17 and IFN type I and II signaling, offering new opportunities to develop novel clinical applications based on a more rational understanding of the disease.

Feline chronic gingivostomatitis current concepts in clinical management

PRACTICAL RELEVANCE

Feline chronic gingivostomatitis (FCGS) is a debilitating disease for cats and a challenge for veterinarians and cat caregivers alike. Recent literature indicates that the disease is immune-mediated in nature and likely associated with a chronic viral infection in patients with higher alpha diversity of their subgingival microbiome. The immune-mediated nature of FCGS includes both local as well as systemic effects, and the transcriptomic analysis of affected patients supports these findings.

TREATMENT OPTIONS

Localized therapy in the form of surgical extraction of all, or nearly all, teeth continues to be the mainstay of treatment. For cats that do not respond to surgical management, medical management, in the form of immunosuppressive or immunomodulatory therapy, remains an option. Analgesia is of fundamental importance. Immunomodulation utilizing mesenchymal stromal cell therapy provides an alternative treatment avenue for refractory patients and likely targets the chronic viral infection present in this disease. The potential for treatment stratification and use of novel systemic treatment options may be revealed as the molecular pathways involved in this disease are better described.

AIMS

This review outlines current and emerging concepts linking available science pertaining to FCGS and clinical management of the disease.

EVIDENCE BASE

The article draws on the best evidence base at this juncture and is also driven by the authors' collective experience of working on the disease for over a decade.

Feline calicivirus and natural killer cells: A study of its relationship in chronic gingivostomatitis

Background and Aims

Feline chronic gingivostomatitis (FCGS) is a frequent chronic inflammatory condition in the oral cavity with an etiopathogenesis not completely identified. This study aimed to contribute to the knowledge of FCGS by identifying the presence of feline calicivirus (FCV) antigens and natural killer (NK) cells and comparing them.

Materials and Methods

Forty biopsies from the oral mucosa of cats diagnosed with chronic gingivostomatitis were subjected to immunohistochemical techniques to evaluate cells with FCV antigens and NK cells positive for CD56.

Results

NK cells were identified in all samples, with an average of 725.3 ± 409.1 cells. Regarding FCV, it was identified in 18 out of 30 samples (60%), with a different number of cells with virus in between the analyzed cases. In all cases, the number of cells infected with FCV was lower than the number of NK cells present in the same samples, but there was no statistical association between them.

Conclusion

This preliminary study shows that NK cells are present in gingivostomatitis lesions not exclusively caused by FCV-stimulus, as only 60% of all cases were positive for this virus, but other antigens should be considered in the etiology of FCGS.

Mesenchymal Stem Cells: Generalities and Clinical Significance in Feline and Canine Medicine

Mesenchymal stem cells (MSCs) are multipotent cells: they can proliferate like undifferentiated cells and have the ability to differentiate into different types of cells. A considerable amount of research focuses on the potential therapeutic benefits of MSCs, such as cell therapy or tissue regeneration, and MSCs are considered powerful tools in veterinary regenerative medicine. They are the leading type of adult stem cells in clinical trials owing to their immunosuppressive, immunomodulatory, and anti-inflammatory properties, as well as their low teratogenic risk compared with pluripotent stem cells. The present review details the current understanding of the fundamental biology of MSCs. We focus on MSCs' properties and their characteristics with the goal of providing an overview of therapeutic innovations based on MSCs in canines and felines.

Transcriptomic signatures of feline chronic gingivostomatitis are influenced by upregulated IL6

Feline chronic gingivostomatitis (FCGS) is a relatively common and debilitating disease characterized by bilateral inflammation and ulceration of the caudal oral mucosa, alveolar and buccal mucosa, and varying degrees of periodontal disease. The etiopathogenesis of FCGS remains unresolved. In this study, we performed bulk RNA-seq molecular profiling of affected tissues derived from a cohort of client-owned cats with FCGS compared to tissues from unaffected animals, to identify candidate genes and pathways that can help guide future exploration of novel clinical solutions. We complemented transcriptomic findings with immunohistochemistry and in situ hybridization assays to better understand the biological significance of the results and performed RNA-seq validation of selected differentially expressed genes using qPCR assays to demonstrate technical reproducibility. Transcriptomic profiles of oral mucosal tissues in cats with FCGS are enriched with immune- and inflammation-related genes and pathways that appear to be largely influenced by IL6 , and include NFKB, JAK/STAT, IL-17 and IFN type I and II signaling, offering new opportunities to develop novel clinical applications based on a more rational understanding of the disease.

Prevalence of feline chronic gingivostomatitis in feral cats and its risk factors

OBJECTIVES

This study investigated the prevalence of feline chronic gingivostomatitis in urban feral cats in South Korea and analysed its risk factors.

METHODS

Three hundred and forty-five feral cats that visited the hospital for neutering using a trap-neuter-return approach were screened for feline chronic gingivostomatitis based on clinical criteria. In addition, we determined if body weight, sex and the presence of tongue lesions are risk factors for feline chronic gingivostomatitis. The difference in severity due to the presence or absence of risk factors, and the relationship between gross findings and histopathological lesions, were analysed by grading lesion severity.

RESULTS

Feline chronic gingivostomatitis was diagnosed in 92 cats. Disease prevalence did not significantly differ with body weight and sex but was significantly related to tongue lesions.

CONCLUSIONS AND RELEVANCE

The prevalence of feline chronic gingivostomatitis in urban feral cats in South Korea was 26.6%. It was significantly more prevalent in cats that had tongue lesions. Severity was also significantly associated with tongue lesions. Feline chronic gingivostomatitis may be associated with an infectious agent that causes tongue lesions.

Mesenchymal stromal cell therapy for feline chronic gingivostomatitis: Long term experience

Introduction

Mesenchymal stromal cells (MSC) therapy has emerged as a potential treatment option for refractory FCGS. However, there is a lack of long-term data on the use of MSC therapy in cats. This study aimed to evaluate the long-term safety and efficacy of MSC therapy for FCGS and investigate potential factors associated with treatment outcomes.

Methods

This study was a retrospective evaluation of 38 client-owned cats with refractory FCGS who received MSC therapy. Medical records, histopathology, and the Stomatitis Activity Disease Index (SDAI) were reviewed. Correlations of the long-term follow-up success rates with SDAI and cell line type used were conducted. A client survey was also performed to assess side effect occurrence, quality-of-life following treatment, and overall treatment satisfaction.

Results

Long-term follow-up ranged from 2 to 9 years post-MSC treatment. The overall positive response rate to MSC treatment was 65.5%, with 58.6% of cats exhibiting permanent improvement or cure. Adverse effects occurring during or immediately after treatment were noted in 34.2% of cases, the majority being transient, self-resolving transfusion-like reactions. No long-term adverse events were noted. No significant correlation in outcome was detected between allogeneic and autologous MSC treatment (p = 0.871) or the severity of the SDAI at entry (p = 0.848) or exit (p = 0.166), or the delta SDAI between entry and exit (p = 0.178). The status 6 months (none to partial improvement vs. substantial improvement to resolution) post-therapy was a predictor of long-term response (value of p < 0.041). Most clients were satisfied with the treatment and outcomes, with 90.6% willing to pursue treatment again, given a similar situation.

Discussion

The results of this study support the use of both autologous and allogeneic MSC as an efficacious and safe therapeutic option for refractory FCGS.

Management of Severe Oral Inflammatory Conditions in Dogs and Cats

Severe oral inflammatory disease is not uncommon in the mouths of canine and feline patients. An approach to oral diagnosis is offered. This article discusses a brief review of important points in the oral diagnosis and management of main canine (canine chronic ulcerative stomatitis (CCUS), eosinophilic stomatitis, and Wegener's granulomatosis (WG)) and feline diseases (feline gingivostomatitis/caudal stomatitis, oral eosinophilic lesions, pyogenic granuloma, and autoimmune diseases with oral manifestations), and-whereby possible-information about the current understanding of disease pathogenesis and treatment is offered.

A Case Series Analysis of Dental Extractions' Outcome in Cats with Chronic Gingivostomatitis Carrying Retroviral Disease

Simple Summary

Feline chronic gingivostomatitis (FCGS) is a chronic, painful, oral inflammatory disease, which can be associated with retroviral disease comorbidity’s, namely feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV). A total 111 case series of cats affected by this oral disease, treated with dental extractions, were analyzed retrospectively, considering if they carried or not one of these retroviral diseases. Cats with lingual ulcers, independently from their retroviral status, were 2.7 times more prone to have a worse response to dental extractions than cats without lingual ulcers. When compared with cats without retroviral disease, FeLV-positive cats presented less proliferative lesions and tended to have more lingual ulcers. Furthermore, these cats had a significantly worse outcome, with 7.5 times more chances of having no improvement.

Abstract

This study aims to evaluate and compare the clinical outcome after dental extractions of cats with FCGS infected with feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV). A retrospective case series included cats with diagnosis of FCGS, availability of detailed clinical records, full-mouth dental radiographs, and retroviral disease test results. Effectiveness of surgical treatment (EOT) was registered. Three groups were defined: control, FIV and FeLV. In this study, 111 cats were included: 60 controls, 29 FIV- and 22 FeLV-positive cats. When compared with control cases, FeLV-positive cats had significantly less proliferative stomatitis lesions, and they tended to have more lingual ulcers. Concurrently, FeLV-positive cats had significantly less tooth resorptive lesions. No other significant differences in FCGS clinical signs were found between groups. FeLV-positive cats had a significantly worse outcome after dental extractions compared to the other groups. In fact, FeLV-positive cats had 7.5 times more chances of having no improvement after dental extractions. This study concludes that the response to dental extractions in FeLV-positive cats is significantly worse, when comparing to cats that do not carry retroviral disease. Therefore, it is important to acknowledge the effect of FeLV status on the prognosis of these cats.

Feline adipose-derived mesenchymal stem cells induce effector phenotype and enhance cytolytic function of CD8+ T cells

BACKGROUND

Feline adipose-derived mesenchymal stem cells (ASCs) engage with a variety of immune cells and have been used in several clinical trials for the treatment of inflammatory and immune-dysregulated diseases in cats, but the impact they exert on the functional characteristics on T cells, particularly CD8+ T cells, remains to be elucidated.

METHODS

Modified mixed leukocyte reaction was performed between feline ASCs and PBMCs. Changes of cell cycle stages, phenotype and cellular senescence were determined through flow cytometry and gene expression analysis. Cytotoxicity assay was performed to evaluate CD8+ T cell effector function.

RESULTS

Feline ASCs induce cell cycle arrest on CD8+ T cells in a contact-dependent manner, downregulate CD8 surface expression, and shift their phenotype toward terminally differentiated effector cells (CD57+, CD45R+, CD62L-). CD8 T cells interacted with feline ASCs also upregulated granzyme B, IL-2 and KLRG-1 expression and have enhanced cytotoxic potential, evident by the increased percentage of lysis on target cells.

CONCLUSIONS

Our findings suggest that feline ASCs (1) alter CD8+ T cells toward terminally differentiated, proinflammatory effector phenotype with limited proliferative capacity, and (2) enhance their cytotoxic potential through granzyme B upregulation. These cytotoxic CD8+ T cells could aid in disease cure in cases caused by an underlying, unresolved viral infection.

Use of unbiased metagenomic and transcriptomic analyses to investigate the association between feline calicivirus and feline chronic gingivostomatitis in domestic cats

OBJECTIVE

To identify associations between microbes and host genes in cats with feline chronic gingivostomatitis (FCGS), a debilitating inflammatory oral mucosal disease with no known cause, compared with healthy cats and cats with periodontitis (control cats).

ANIMALS

19 control cats and 23 cats with FCGS.

PROCEDURES

At least 1 caudal oral mucosal swab specimen was obtained from each cat. Each specimen underwent unbiased metatranscriptomic next-generation RNA sequencing (mNGS). Filtered mNGS reads were aligned to all known genetic sequences from all organisms and to the cat transcriptome. The relative abundances of microbial and host gene read alignments were compared between FCGS-affected cats and control cats and between FCGS-affected cats that did and did not clinically respond to primary treatment. Assembled feline calicivirus (FCV) genomes were compared with reverse transcription PCR (RT-PCR) primers commonly used to identify FCV.

RESULTS

The only microbe strongly associated with FCGS was FCV, which was detected in 21 of 23 FCGS-affected cats but no control cats. Problematic base pair mismatches were identified between the assembled FCV genomes and RT-PCR primers. Puma feline foamy virus was detected in 9 of 13 FCGS-affected cats that were refractory to treatment and 5 healthy cats but was not detected in FCGS-affected cats that responded to tooth extractions. The most differentially expressed genes in FCGS-affected cats were those associated with antiviral activity.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that FCGS pathogenesis has a viral component. Many FCV strains may yield false-negative results on RT-PCR-based assays. Coinfection of FCGS-affected cats with FCV and puma feline foamy virus may adversely affect response to treatment.

A pilot study to evaluate the serum Alpha-1 acid glycoprotein response in cats suffering from feline chronic gingivostomatitis

BACKGROUND

Feline chronic gingivostomatitis (FCGS) is a multifactorial immune-mediated disease that can lead to chronic pain, anorexia, and weight loss and has substantial health and welfare effects. Currently, the recommended treatment includes dental extractions to decrease the inflammatory stimulation associated with dental plaque. However, complete remission is observed in less than half of the cases, and the majority need comprehensive medical management. This study aimed to evaluate the serum levels of the acute phase protein alpha-1 acid glycoprotein (AGP) in cats with FCGS and to examine whether dental extractions contribute to a significant decrease in the systemic inflammatory response at two postoperative time points.

RESULTS

AGP serum concentrations in the cats with FCGS were significantly higher at all time points than that in the control groups and were significantly correlated with the global caudal stomatitis score at day 0 but not at day 30 or 60. A significant improvement of some clinical scores, such as perceived comfort and global caudal stomatitis, was observed 60 days after the dental extraction. However, the levels of AGP did not significantly change over time.

CONCLUSIONS

Cats with FCGS were more likely to have a systemic inflammatory response compared with age- and dental disease-matched controls. Dental extractions, in most cases, did not contribute to a significant decrease of AGP both at 30 and 60 days. Therefore, this study reinforces the need to pursue comprehensive medical management after dental extractions to attenuate the systemic inflammatory response as a result of this disease.

Histological, Immunological, and Genetic Analysis of Feline Chronic Gingivostomatitis

Feline chronic gingivostomatitis (FCGS) is an immune-mediated inflammatory condition affecting the oral mucosa that results in substantial pain and suffering. The goal of this study was to complete an in-depth immunohistochemistry analysis of affected FCGS mucosa, to perform and compare immune cell phenotypes in the blood of FCGS and healthy controls cats, and to determine a transcriptomic profile of the affected and normal oral mucosa of FCGS cats. We hypothesized that cats with FCGS would have circulating activated CD8+ T cells and that tissues would be infiltrated with activated B and T cells with a highly proinflammatory transcriptome. We found that oral mucosal tissues from cats with FCGS have high tissue infiltration of B cells and that T cells include both CD4+ and CD8+ lymphocytes. Cells positive for CD25 (IL2 receptor, indicative of lymphocyte activation) and FOXP3 (indicative of regulatory T cells) were scattered throughout the mucosa. Compared to healthy individuals, cats with FCGS had high circulating CD8+ effector memory cells with a concurrent decrease in central memory cells and evidence of circulating activated CD8+ T cells (CD25+, CD62L−). Gene expression in the affected tissues was enriched for genes associated with T-cell signaling, cell adhesion molecules, leukocyte migration, inflammatory signaling pathways, extracellular matrix-receptor interactions, cytokine-cytokine receptor interactions, and natural killer cell-mediated cytotoxicity, among others. These data are essential to understand disease pathogenesis, to inform mechanism of action studies for future and current therapies, and to help select prognostic biomarkers and potency assays for stem cell treatment of FCGS.

A multicenter experience using adipose-derived mesenchymal stem cell therapy for cats with chronic, non-responsive gingivostomatitis

BACKGROUND

The ability of mesenchymal stem cells (MSCs) to modulate immune responses inspired a series of clinical trials addressing oral mucosal inflammation. We previously reported on the safety and efficacy of fresh, allogeneic and autologous, adipose-derived mesenchymal stem cells (ASCs) to treat feline gingivostomatitis (FCGS), an oral mucosal inflammatory disease that shares similarities with human oral lichen planus.

METHODS

To meet clinical demand and goals for future commercialization, we determined the feasibility of shipping fresh ASCs to distant clinics and extended our pilot studies to expand safety and efficacy data for shipped and non-shipped ASCs in a cohort of 18 FCGS cats enrolled locally and at a few different locations within the USA.

RESULTS

We found that ASCs retained their viability, phenotype, and function after shipment. ASCs administered systemically resulted in a 72% positive response rate, identical to that noted in our previous studies. Cats that responded to ASC therapy had a significant decrease in circulating globulin concentration and histological evidence of decreased CD3+ T cells and CD20+ B cells in the oral mucosa. Responder cats also had significantly decreased percentages of CD8^lo cells in blood prior to and at 3 months post-ASC therapy. CD8^lo cells may serve as a potential "predictor" for response to systemic ASC therapy.

CONCLUSION

Fresh feline ASCs can be successfully shipped and administered to cats with FCGS. ASCs modulate the immune response and demonstrate efficacy for chronic oral mucosal inflammatory lesions that are characterized by CD8+ T cell inflammation and T cell activation. FCGS is a potentially useful naturally occurring large animal model of human oral inflammatory diseases.

Non-murine models to investigate tumor-immune interactions in head and neck cancer

The immune response has important roles in the biology of solid tumors, including oncogenesis, tumor growth, invasion and metastasis, and response to treatment. Improved understanding of tumor-immune system interactions has provided promising therapeutic options that are based on the rescue and enhancement of the anti-tumoral host response. Immune-based treatments have been approved for clinical use in various types of cancer, including head and neck cancer (HNC); other strategies involving combination therapies are currently in development. These novel therapies were developed based on knowledge derived from in vitro, in silico, and in vivo pre-clinical studies. However, clinical trials seldom replicate the efficacy observed in pre-clinical animal studies. This lack of correlation between pre-clinical studies and clinical trials may be related to limitations of the models used; which highlights the relevance of considering immune-related aspects of different pre-clinical models. Murine models are the most frequently used pre-clinical models of HNC and are discussed elsewhere. Non-murine models have characteristics that offer unique opportunities for the study of HNC etiology, therapeutic strategies, and tumor-immune system interactions. The current review focuses on immune-related aspects of non-murine models, including dog, cat, pig, zebrafish, and frog, that could be used to investigate tumor-immune interactions in HNC.

Prevalence of microorganisms associated with feline gingivostomatitis

OBJECTIVES

Feline gingivostomatitis (FGS) is a painful chronic inflammatory disease of the oral cavity. The purpose of this study was to examine the frequency of detection of certain common feline bacteria and viruses to determine any potential associations with FGS.

METHODS

A multicentre case-control study design was conducted. In total, 72 control cats and 32 cats with FGS were included in the study. Oral swabs were cultured for bacterial identification and a PCR assay was carried out to examine the infection of feline calicivirus (FCV), feline herpesvirus-1 (FHV-1), Chlamydia felis, Mycoplasma felis and Bordetella bronchiseptica.

RESULTS

There was a significant difference in age distribution between the control and the FGS group. Based on a PCR assay, the positive rate of FCV was significantly higher in FGS cats than control animals. For other infectious pathogens, including FHV-1, C felis and M felis, there was no significant difference. Bacterial culture of oral swabs revealed that Pasteurella multocida was most frequently detected, but the detection rate was significantly lower in FGS cats. In FGS cats, the incidence of Enterococcus faecalis and anaerobic bacteria were more frequently isolated than in control cats.

CONCLUSIONS AND RELEVANCE

This study indicates that the positive rate of FCV was significantly higher in cats with FGS, and the microflora of the oral cavity of cats with FGS might be disrupted, although additional studies are required to compare the oral microbiome in cats of a variety of ages.

Aspectos clínicos e laboratoriais do complexo gengivite-estomatite em gatos domésticos

RESUMO Foram incluídos 76 gatos domésticos com diferentes graus (I a IV) de lesões em cavidade oral, os quais foram avaliados clinicamente e tiveram coletadas amostras de sangue e suabes da cavidade oral. A maioria dos gatos portadores de CGE eram machos, castrados, adultos, sem raça definida e com estilo de vida confinado. Os sinais clínicos observados e associados à gravidade da inflamação na cavidade oral foram halitose (98,7%); ptialismo (22,4%); hemorragia bucal (9,2%) e úlcera na parte superior dos lábios (2,6%); desconforto à manipulação da cavidade oral (44,7%) e perda dentária (55,3%). A maioria dos gatos avaliados foi classificada no grau II (43,4%). Não se observou diferença significativa nos resultados do eritrograma dos gatos portadores de CGE, independentemente da gravidade das lesões e da sintomatologia clínica. Entretanto, observou-se neutrofilia (21,1%) e aumento de proteínas plasmáticas totais (47,3%), na maioria dos animais de grau II, sugerindo que esses parâmetros laboratoriais, quando aumentados, possam estar associados a graus menos graves de CGE. A análise das lâminas de citologia da cavidade oral dos gatos demonstrou que a presença de Simonsiella spp. foi mais frequente nos animais incluídos no grau IV, entretanto não é possível afirmar que essa bactéria esteja relacionada à gravidade das lesões.

Investigation of immune cell markers in feline oral squamous cell carcinoma

Squamous cell carcinoma is the most common oral cancer in the cat and presents as a locally aggressive lesion for which an effective therapeutic protocol remains elusive. Feline oral squamous cell carcinoma (OSCC) shares many clinical characteristics with human head and neck squamous cell carcinoma (HNSCC). Accordingly, present studies were conducted to determine similarities for immune markers shared by feline OSCC and human HNSCC. Biopsies harvested from a feline patient cohort-1 (n = 12) were analyzed for lymphoid cell infiltrates by immunohistochemistry (IHC). Results revealed unique patterns of T cell infiltration involving both neoplastic epithelium and stroma that were detected in most patient tumor biopsies (92%) examined by IHC staining for CD3. Intratumoral B cell infiltrates were detected within tumor stroma only, based on IHC staining for CD79a and CD20 for all patients within the same cohort-1. Infiltration of tumors by a regulatory CD4 T cell subset (Tregs) defined by expression of the forkhead transcription factor FoxP3, was also detected in biopsies from 57% of patients and involved infiltration of neoplastic epithelium and stroma. Patient biopsies were also examined for expression of immunomodulator cyclooxygenase (COX)-2 and revealed positive but weak staining of neoplastic epithelium in a significant proportion of cases (75%). Interestingly, COX-2 expression was detected in both neoplastic epithelium and stroma. Blood collected from a second cohort of feline OSCC patients (n = 9) revealed an increased frequency of circulating CD4+FoxP3+ T cells when compared to healthy adult controls (n = 7) (P = 0.045), although frequencies of CD4+CD25+FoxP3+ T cells were comparable between patients and healthy pet cat controls. Lastly, biopsies from feline OSCC patients were characterized for histologic subtype using a classification scheme previously described for human HNSCC. This analysis revealed the conventional subtype as the predominant variant (75%) with conventional subtypes split evenly between well differentiated and moderately differentiated carcinomas. Two cases were classified as papillary and one case as basaloid subtypes. Correlations between subtype, immune marker scores or circulating Treg frequencies and clinical characteristics or outcome were not detected, most likely due to small patient numbers within patient cohorts. However, findings from these studies provide a preliminary step in the characterization of immune and histologic markers that will be critical to defining prognostic immune markers for feline OSCC and potential targets for testing of immunotherapeutics also relevant to human HNSCC in future studies.

Mesenchymal stem cell therapy in cats: Current knowledge and future potential

Practical relevance: Stem cell therapy is an innovative field of scientific investigation with tremendous potential for clinical application in veterinary medicine. Based on the known desirable immunomodulatory properties of mesenchymal stem cells, this therapy holds promise for the treatment of a variety of inflammatory diseases in cats.

AIMS

This review details our current understanding of feline stem cell biology and proposed mechanism of action. Studies performed in feline clinical trials for diseases including gingivostomatitis, chronic enteropathy, asthma and kidney disease are summarized, with the goal of providing an overview of the current status of this treatment modality and its potential for the future.

Relationship between Feline calicivirus Load, Oral Lesions, and Outcome in Feline Chronic Gingivostomatitis (Caudal Stomatitis): Retrospective Study in 104 Cats

Objective

This study was performed to assess the relationship between oral Feline calicivirus (FCV) load and severity of lesions at the time of presentation of cats suffering from feline chronic gingivostomatitis (FCGS) (part 1) and treatment outcome after dental extractions (part 2). We hypothesized that a higher FCV viral load would be positively correlated with the severity of lesions at presentation and negatively correlated with treatment outcome. In addition, the effect of dental extractions on outcome and the influence of preoperative severity of lesions on the outcome were investigated.

Materials and methods

Cats with FCGS were included in the study if they had been diagnosed with caudal stomatitis, had been tested positive for FCV using a real-time reverse transcriptase-PCR test on oropharyngeal swab, and had dental extractions performed within the authors’ department. General practitioners provided all previous medical treatments. Cats with recheck examinations were included in part 2 of the study. Multivariate statistical analysis was performed to assess the relationship between the different parameters.

Results

One hundred four cats met the requirements for part 1 and 56 cats for part 2 of the study. Data collected from patients’ record included patient history, viral testing results, extent and severity of oral lesions, extent of teeth extraction. Signalment, history, preoperative treatment, and severity of caudal and alveolar stomatitis score were not associated with FCV load (P > 0.05). Presence of lingual ulcers was significantly correlated with FCV load (P = 0.0325). Clinical cure (32.1%) or very significant improvement (19.6%) was achieved in 51.8% of cats within 38 days. Concomitantly, 60.7% of the owners considered their cat cured (41.1%) or significantly improved (19.6%). Extent of teeth extraction was not found to influence the clinical outcome (P > 0.05).

Conclusion

The results of this study did not support the hypothesis that FCV oral load is correlated with the severity of oral lesions or with the outcome following dental extractions. In addition, the severity of caudal inflammation was not correlated with healing time or achievement of cure.

Therapeutic Efficacy of Fresh, Allogeneic Mesenchymal Stem Cells for Severe Refractory Feline Chronic Gingivostomatitis

Mesenchymal stem cells (MSCs) have potent immunomodulatory functions and are a promising therapy for immune‐mediated inflammatory disorders. We previously demonstrated the efficacy of fresh, autologous, adipose‐derived MSCs (ASCs) to treat feline chronic gingivostomatitis (FCGS), a chronic oral mucosal inflammatory disease similar to human oral lichen planus. Here, we investigate the use of fresh allogeneic ASCs for treatment of FCGS in seven cats. Radiolabeled ASCs were also tracked systemically. Each cat received two intravenous injections of 20 million ASCs, 1 month apart. Oral inflammation, blood lymphocyte subsets, anti‐fetal bovine serum antibody levels, ASC crossmatching and serum proteins and cytokine concentrations were determined. Four of the 7 cats (57%) responded to treatment [complete clinical remission (n = 2) or substantial clinical improvement (n = 2)]. Three cats were nonresponders. Prior to therapy, most cats had increased circulating CD8+ T cells, decreased CD8^lo cells, and a decreased CD4/CD8 ratio, however clinical resolution was not associated with normalization of these parameters. Nonresponders showed more severe systemic inflammation (neutrophilia, hyperglobulinemia and increased interferon gamma and tumor necrosis factor alpha concentration) prior to ASC therapy. Clinical remission took up to 20 months and no clinical relapse has occurred. A higher fraction of radiolabeled ASCs were identified in the oral cavity of FCGS affected cats than the control cat. The administration of fresh, allogenic ASCs appeared to have lower clinical efficacy with a delayed response as compared to the fresh, autologous ASCs. In addition, the mechanism(s) of action for autologous and allogenic ASCs may differ in this model of oral inflammation. Stem Cells Translational Medicine2017;6:1710–1722

Clinical, pathological, immunohistochemical and molecular characterization of feline chronic gingivostomatitis

Objectives This study presents the clinical, pathological, immunohistochemical and molecular characterization of 26 cats with feline chronic gingivostomatitis (FCG). Methods Oral mucosal biopsies, blood and swabs were collected from cats presenting with oral lesions. The tissue sections were submitted for histopathology and immunohistochemical analysis for feline calicivirus (FCV), feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV). The swabs were subjected to PCR analysis for FCV, and blood for FeLV and FIV. Results The main clinical findings were dysphagia (88.2%), halitosis (76.5%), sialorrhea (47.1%), weight loss (41.2%), intense oral discomfort (35.3%), oral hemorrhage (17.6%), and lackluster and fragile coat (11.8%). Gross inspection revealed bilateral lesions across the palatoglossal fold to the lateral tongue base. The lesions were diffuse, proliferative, intensely red and friable, and bled easily upon examination in 80.8% of cases. In 23.1% of cases, the lesions were multifocal to coalescent, at times forming multiple vesicles on a reddened, edematous palatoglossal fold. Microscopic examination showed that 15.4% of lesions had moderate (grade 2) and 84.6% had severe (grade 3) inflammation. Immunohistochemistry revealed the presence of FeLV antigens in the epithelium and the inflammatory infiltrate of 30.8% of the cats with FCG. FCV antigens were not detected in the FCG lesions. Conclusions and relevance The FCG cases analyzed could not be correlated with FCV. It is possible that FeLV plays a role as a causal agent of lesions in cases where the presence of the virus has been confirmed by immunohistochemistry in epithelial samples.

Human and feline adipose-derived mesenchymal stem cells have comparable phenotype, immunomodulatory functions, and transcriptome

Background

Adipose-derived mesenchymal stem cells (ASCs) are a promising cell therapy to treat inflammatory and immune-mediated diseases. Development of appropriate pre-clinical animal models is critical to determine safety and attain early efficacy data for the most promising therapeutic candidates. Naturally occurring diseases in cats already serve as valuable models to inform human clinical trials in oncologic, cardiovascular, and genetic diseases. The objective of this study was to complete a comprehensive side-by-side comparison of human and feline ASCs, with an emphasis on their immunomodulatory capacity and transcriptome.

Methods

Human and feline ASCs were evaluated for phenotype, immunomodulatory profile, and transcriptome. Additionally, transwells were used to determine the role of cell-cell contact in ASC-mediated inhibition of lymphocyte proliferation in both humans and cats.

Results

Similar to human ASCs, feline ASCs were highly proliferative at low passages and fit the minimal criteria of multipotent stem cells including a compatible surface protein phenotype, osteogenic capacity, and normal karyotype. Like ASCs from all species, feline ASCs inhibited mitogen-activated lymphocyte proliferation in vitro, with or without direct ASC-lymphocyte contact. Feline ASCs mimic human ASCs in their mediator secretion pattern, including prostaglandin E2, indoleamine 2,3 dioxygenase, transforming growth factor beta, and interleukin-6, all augmented by interferon gamma secretion by lymphocytes. The transcriptome of three unactivated feline ASC lines were highly similar. Functional analysis of the most highly expressed genes highlighted processes including: 1) the regulation of apoptosis; 2) cell adhesion; 3) response to oxidative stress; and 4) regulation of cell differentiation. Finally, feline ASCs had a similar gene expression profile to noninduced human ASCs.

Conclusions

Findings suggest that feline ASCs modulate lymphocyte proliferation using soluble mediators that mirror the human ASC secretion pattern. Uninduced feline ASCs have similar gene expression profiles to uninduced human ASCs, as revealed by transcriptome analysis. These data will help inform clinical trials using cats with naturally occurring diseases as surrogate models for human clinical trials in the regenerative medicine arena.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0528-z) contains supplementary material, which is available to authorized users.

Immunohistochemical Analysis of Leucocyte Subsets in the Sinonasal Mucosa of Cats with Upper Respiratory Tract Aspergillosis

Leucocyte populations in the sinonasal mucosa of cats with and without upper respiratory tract aspergillosis were compared using immunohistochemistry and computer-aided morphometry. Inflammation was identified in the nasal mucosa of all affected cats, comprising predominantly of lymphoplasmacytic infiltration of the lamina propria associated with epithelial proliferation and degeneration. There was intense and diffuse expression of class II antigens of the major histocompatibility complex, associated with sites of hyphal invasion with hyperplasia and ulceration of the epithelium adjacent to fungal elements. Significantly more CD79b(+) cells, total lymphocytes, immunoglobulin (Ig)-expressing cells and MAC387(+) cells infiltrated the epithelium and more IgG(+) cells and total Ig-expressing cells infiltrated the lamina propria in affected cats compared with controls. Importantly, the inflammatory profile in affected cats was not consistent with the T helper (Th)1 and Th17 cell-mediated response that confers protective acquired immunity against invasive aspergillosis in dogs and people and in murine models of the infection. This finding may help to explain the development of invasive aspergillosis in systemically immunocompetent cats.

Effect of tooth extraction on stomatitis in cats: 95 cases (2000-2013)

OBJECTIVE

To evaluate long-term response of cats with stomatitis to tooth extraction.

DESIGN

Retrospective case series.

ANIMALS

95 cats with stomatitis.

PROCEDURES

Medical records of cats with stomatitis that was treated with tooth extraction during a 14-year period were reviewed. Demographic information and diagnostic results were recorded as well as surgical procedure, including full-mouth extraction (FME) versus partial-mouth extraction (PME), and specifics of medical management. Patients were categorized according to response to treatment.

RESULTS

Median postoperative follow-up time was 231 days (range, 33 to 2,655 days). Of 95 cats, 6 (6.3%) had no improvement and 25 (26.3%) had little improvement in stomatitis following tooth extraction and extended medical management (EMM). Following tooth extraction, 37 (39.0%) cats had substantial clinical improvement and 27 (28.4%) cats had complete resolution of stomatitis; of these 64 cats, 44 (68.8%) required EMM for a finite period to achieve positive outcomes. Extent of tooth extraction (PME vs FME) was not associated with overall response to treatment. At initial recheck examination, a better long-term response to tooth extraction was observed in patients with resolution of abnormal behavior (OR, 7.2), decrease in oral inflammation (OR, 3.5), and lack of need for follow-up medical management with antimicrobials (OR, 3.7).

CONCLUSIONS AND CLINICAL RELEVANCE

Extraction of teeth in areas of oral inflammation provided substantial improvement or complete resolution of stomatitis in more than two-thirds of affected cats. Full-mouth extraction did not appear to provide additional benefit over PME. Most cats with stomatitis may require EMM to achieve substantial clinical improvement or complete resolution.

Therapeutic Efficacy of Fresh, Autologous Mesenchymal Stem Cells for Severe Refractory Gingivostomatitis in Cats

Mesenchymal stem cells (MSCs) are a promising therapy for immune-mediated and inflammatory disorders, because of their potent immunomodulatory properties. In this study, we investigated the use of fresh, autologous, adipose-derived MSCs (ASCs) for feline chronic gingivostomatitis (FCGS), a chronic, debilitating, idiopathic, oral mucosal inflammatory disease. Nine cats with refractory FCGS were enrolled in this pilot study. Each cat received 2 intravenous injections of 20 million autologous ASCs, 1 month apart. Oral biopsies were taken before and at 6 months after the first ASC injection. Blood immune cell subsets, serum protein, and cytokine levels were measured at 0, 1, 3, and 6 months after treatment to assess immunomodulatory effects. Seven of the 9 cats completed the study. Five cats responded to treatment by either complete clinical remission (n=3) or substantial clinical improvement (n=2). Two cats were nonresponders. Cats that responded to treatment also exhibited systemic immunomodulation demonstrated by decreased numbers of circulating CD8+ T cells, a normalization of the CD4/CD8 ratio, decreased neutrophil counts, and interferon-γ and interleukin (IL)-1β concentration, and a temporary increase in serum IL-6 and tumor necrosis factor-α concentration. No clinical recurrence has occurred following complete clinical remission (follow-up of 6-24 months). In this study, cats with <15% cytotoxic CD8 T cells with low expression of CD8 (CD8lo) cells were 100% responsive to ASC therapy, whereas cats with >15% CD8lo cells were nonresponders. The relative absence of CD8lo cells may be a biomarker to predict response to ASC therapy, and may shed light on pathogenesis of FCGS and mechanisms by which ASCs decrease oral inflammation and affect T-cell phenotype.

SIGNIFICANCE

This study is the first to demonstrate the safety and efficacy of fresh, autologous, adipose-derived stem cell systemic therapy for a naturally occurring, chronic inflammatory disease in cats. The findings demonstrate that this therapy resulted in complete clinical and histological resolution or reduction in clinical disease severity and immune modulation in most cats. This study also identified a potentially useful biomarker that could dictate patient enrollment and shed light on immune modulation mechanism. As a naturally occurring animal model, FCGS also provides a strategic platform for potentially translatable therapy for the treatment of human oral inflammatory disease.

Association between oral health status and retrovirus test results in cats

OBJECTIVE

To determine associations between oral health status and seropositivity for FIV or FeLV in cats.

DESIGN

Cross-sectional survey.

ANIMALS

5,179 cats.

PROCEDURES

Veterinarians at veterinary clinics and animal shelters completed online training on oral conditions in cats and then scored oral health status of cats with no known history of vaccination against FIV. Age, sex, and results of an ELISA for retroviruses were recorded. Results were analyzed by means of standard logistic regression with binary outcome.

RESULTS

Of 5,179 cats, 237 (4.6%) and 186 (3.6%) were seropositive for FIV and FeLV, respectively, and of these, 12 (0.2%) were seropositive for FIV and FeLV. Of all 5,179 cats, 1,073 (20.7%) had gingivitis, 576 (11.1%) had periodontitis, 203 (3.9%) had stomatitis, and 252 (4.9%) had other oral conditions (overall oral disease prevalence, 2,104/5,179 [40.6%]). Across all age categories, inflammatory oral disease was associated with a significantly higher risk of a positive test result for FIV, compared with the seropositivity risk associated with other oral diseases or no oral disease. Stomatitis was most highly associated with risk of FIV seropositivity. Cats with any oral inflammatory disease were more likely than orally healthy cats to have a positive test result for FeLV. Increasing age was associated with a higher prevalence of oral disease in retrovirus-seronegative cats.

CONCLUSIONS AND CLINICAL RELEVANCE

Inflammatory oral disease was associated with an increased risk of seropositivity for retroviruses in naturally infected cats. Therefore, retroviral status of cats with oral inflammatory disease should be determined and appropriate management initiated.

Feline foamy virus adversely affects feline mesenchymal stem cell culture and expansion: implications for animal model development

Mesenchymal stem cells (MSCs) are a promising therapeutic option for various immune-mediated and inflammatory disorders due to their potent immunomodulatory and trophic properties. Naturally occurring diseases in large animal species may serve as surrogate animal models of human disease, as they may better reflect the complex genetic, environmental, and physiologic variation present in outbred populations. We work with naturally occurring diseases in large animal species to better understand how MSCs work and to facilitate optimal translation of MSC-based therapies. We are investigating the use of MSC therapy for a chronic oral inflammatory disease in cats. During our efforts to expand fat-derived feline MSCs (fMSCs), we observed that∼50% of the cell lines developed giant foamy multinucleated cells in later passages. These morphologic alterations were associated with proliferation arrest. We hypothesized that the cytopathic effects were caused by infection with a retrovirus, feline foamy virus (FFV). Using transmission electron microscopy, polymerase chain reaction, and in vitro assays, we determined that syncytial cell formation and proliferation arrest in fMSCs were caused by FFV strains that were highly homologous to previously reported FFV strains. We determined that the antiretroviral drug, tenofovir, may be used to support ex vivo expansion and salvage of FFV-infected fMSC lines. MSC lines derived from specific pathogen-free cats do not appear to be infected with FFV and may be a source of allogeneic fMSCs for clinical application. FFV infection of fMSC lines may hinder large-scale expansion of autologous MSC for therapeutic use in feline patients.

Dental radiographic findings in cats with chronic gingivostomatitis (2002-2012)

OBJECTIVE

To compare dental radiographic findings in cats with and without feline chronic gingivostomatitis (FCGS).

DESIGN

Retrospective case-control study.

ANIMALS

101 cats with FCGS (cases) and 101 cats with other oral diseases (controls).

PROCEDURES

Controls were age- and treatment date-matched with cases. Conventional full-mouth dental radiographic views were evaluated for distribution, pattern, and severity of alveolar bone loss (periodontitis), tooth resorption, buccal bone expansion, tooth fractures, and retained roots.

RESULTS

All cases and 77 (76%) controls had periodontitis; differences in extent and severity of periodontitis were significant, with semigeneralized or generalized and moderate or severe periodontitis in 78 (77%) and 93 (92%) cases, respectively, and 28 (28%) and 38 (38%) controls, respectively. The pattern of alveolar bone loss in cases was dominated by horizontal bone loss, with a nonsignificant increase in vertical bone loss, compared with that of controls. Cases were more likely than controls to have external inflammatory root resorption (49 [49%] vs 25 [25%]) and retained roots (57 [56%] vs 28 [28%]). Fewer dental fractures occurred in cases (14 [14%]) than in controls (35 [35%]). There were no differences between cases and controls in breed, sex, or presence of feline resorptive lesions or buccal bone expansion.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that FCGS was associated with more widely distributed and severe periodontitis, with a higher prevalence of external inflammatory root resorption and retained roots than other oral diseases. Full-mouth radiographic views are indicated for cats with FCGS to diagnose the extent of associated periodontitis, reveal external inflammatory root resorption, and identify retained roots.

Bovine lactoferrin and piroxicam as an adjunct treatment for lymphocytic-plasmacytic gingivitis stomatitis in cats

Feline lymphocytic-plasmacytic gingivitis/stomatitis (LPGS) or caudal stomatitis is an inflammatory disease that causes painfully erosive lesions and proliferations of the oral mucosa. The disease is difficult to cure and can affect cats at an early age, resulting in lifetime therapy. In this study, a new treatment using a combination of bovine lactoferrin (bLf) oral spray and oral piroxicam was investigated using a randomized double-blinded clinical trial in 13 cats with caudal stomatitis. Oral lesion grading and scoring of clinical signs were conducted during and after the trial to assess treatment outcome. Oral mucosal biopsies were used to evaluate histological changes during and after treatment. Clinical signs were significantly improved in 77% of the cats. In a 4-week study, clinical signs were considerably ameliorated by oral piroxicam during the first 2 weeks. In a 12-week study, the combined bLf oral spray and piroxicam, when compared with piroxicam alone, exhibited an enhanced effect that reduced the severity of the oral lesions (P = 0.059), while also significantly improving clinical signs (P <0.05), quality of life (P <0.05), and weight gain (P <0.05). The remission of oral inflammation was closely correlated with the decreased number of macrophages (OR = 4.719, P < 0.05). There was no detectable influence on liver or kidney function during a 12-week assessment. It was concluded that combining oral bLf spray and piroxicam was safe and might be used to decrease the clinical signs of caudal stomatitis in cats.

Efficacy of Cyclosporine for Chronic, Refractory Stomatitis in Cats: A Randomized, Placebo-Controlled, Double-Blinded Clinical Study

Sixteen cats with chronic stomatitis, that had previously undergone premolar-molar or full-mouth extractions, were randomly assigned a group to receive 2.5 mg/kg cyclosporine or placebo orally twice daily. Neither the clinician nor the clients were aware of the group assignments. Cats were evaluated prior to treatment and every 2 weeks for 6 weeks using a 30 point Stomatitis Disease Activity Index (SDAI) score. Mean improvement in SDAI scores among cats in the treatment group after 6 weeks was 52.7 %. This was significantly different from the mean improvement (12.2 %) of cats in the placebo group. During the 6 week study period, 7 of the 9 cats in the treatment group (77.8 %) showed a > 40 % improvement in SDAI score, while 1 of 7 cats in placebo group (14.3 %) showed a > 40 % improvement in SDAI score. This difference was statistically significant. Individual variability in the absorption of orally-administered cyclosporine was high. Trough whole-blood cyclosporine levels ranged from 32.1 ng/ml to 1,576.2 ng/ml. At the end of the 6 week observation period, there was a statistically significant difference among cats with trough whole-blood cyclosporine levels > 300 ng/ml (72.3 % improvement) compared with cats with cyclosporine levels < 300 ng/ml (28.2 % improvement). Whole-blood cyclosporine levels > 300 ng/ml were associated with significant improvement in oral inflammation in cats with chronic stomatitis that had previously undergone premolar-molar or full-mouth extraction.

The influence of oral bacteria on tissue levels of Toll-like receptor and cytokine mRNAs in feline chronic gingivostomatitis and oral health

Feline chronic gingivostomatitis (FCGS) is an inflammatory disease of the oral cavity that causes severe pain and distress in affected cats. Treatment methods are currently very limited. The aims of this study were to assess the feline innate immune response by investigating the levels of cytokine and Toll-like receptor (TLR) mRNAs in tissue biopsies of cats with and without FCGS, and to relate this to the presence or absence of putative oral pathogens identified previously within these cats. Mucosal biopsies were collected from 28 cats with FCGS and eight healthy cats. The levels of TLR (TLR2, TLR3, TLR4, TLR7, TLR9) and cytokine (IL-1β, IL-4, IL-6, IL-10, IL-12, TNF-α, IFN-γ) mRNA was determined using quantitative PCR. In the FCGS group a statistically significant increase was seen in TLR2, TLR7, TNF-α, IFN-γ, IL-1β and IL-6 mRNA levels compared to the healthy group. In cats where Tannerella forsythia was present, statistically significant increases were seen in TLR2, TLR4, TLR7, TLR9, TNF-α and IL-1β mRNA levels compared to cats where this putative pathogen was absent. Statistically significant increases in mRNA expression were also seen in cats harbouring feline calicivirus (FCV) (TLR2, IL-1β, IL-6, IFN-γ) and Porphyromonas circumdentaria (TLR2, TLR3) compared to cats where these putative pathogens were absent. Pasteurella multocida subsp. multocida and Pseudomonas sp. did not significantly alter the expression of any TLR or cytokine mRNAs when compared to animals who tested negative for these species, while cats colonised with P. multocida subsp. septica demonstrated a statistically significant reduction in the expression of TLR7, TNF-α and IFN-γ mRNAs compared to cats free of this species. The expression of mRNA for several TLRs and cytokines is elevated in FCGS. A positive correlation was observed between clinical disease severity and the presence of FCV (p=0.001; Rho=0.58). Although the number of cats harbouring T. forsythia was low by comparison, 80% of samples in which it was present were from cases with the highest clinical disease severity. Positive correlations with clinical disease severity were seen for TLR2 (p=0.00086), TLR7 (p=0.049), TNF-α (p=0.027), IFN-γ (p=0.0015), IL-1β (p=0.004) and IL-6 (p=0.00001) mRNAs. The putative pathogens FCV and T. forsythia may be important in stimulating a host immune response to FCGS and may play a role in the pathogenesis of this disease.