Interferon as potential treatment for periocular squamous cell carcinoma

Example of SCC, before (left) and after treatment

 with INFα-2b . (c) Martabano et al. For more photos, see

https://doi.org/10.1371/journal.pone.0297366.g001 

Injecting interferon alpha-2b (INFα-2b) may provide a new treatment for periocular squamous cell carcinoma in horses according to a recent report. 

Squamous cell carcinoma (SCC) is a type of skin cancer that commonly affects horses. 

 

SCC typically appears as nodules or masses on the skin or mucous membranes. These lesions can vary in size and colour but often appear ulcerated or crusted. SCC commonly affects areas with less pigment or areas exposed to sunlight, such as the eyelids, lips, and genital regions. 

 

Various treatment options may be considered including surgical excision, cryotherapy (freezing), laser therapy, topical medications, and radiation therapy.

 

A recent clinical investigation conducted by Brittany B. Martabano and colleagues from Colorado State University explored the efficacy of intralesional interferon alpha-2b (INFα-2b) treatment in 11 horses (12 eyes) diagnosed with periarticular squamous cell carcinoma (PSCC). The comprehensive findings of this study have been published in PLOS One.

 

Before commencing treatment, all horses underwent biopsy confirmation of PSCC diagnosis and were deemed healthy otherwise.

 

The treatment regimen involved injections, under sedation, of 10 million IU of INFα-2b every two weeks for a maximum of six sessions. The research team assessed the response by measuring lesion sizes before each treatment and subsequently at one, three, and twelve months after the end of the course of treatment. A response was considered positive if there was a reduction in tumour size exceeding 50%.

 

The researchers also checked for the development of antibodies against INFα-2b and assessed their potential impact on treatment response.

 

Results indicated that five out of twelve eyes (four out of eleven horses) responded positively to the treatment, with two eyes showing complete resolution of PSCC. No systemic adverse effects were observed, although local swelling occurred in six out of eleven horses during treatment, which resolved spontaneously.

 

All horses developed serum anti-IFNα2b antibodies, with no discernible difference in antibody concentration between responders and non-responders.

 

The researchers conclude that injecting IFNα2b into PSCC was well-tolerated in horses and led to tumour regression in 42% of treated eyes. They found no association between treatment failure and the development of IFNα2b antibodies.

 

 

For more details, see:

 

Intralesional interferon alpha-2b as a novel treatment for periocular squamous cell carcinoma in horses

Brittany B. Martabano, Steven Dow, Lyndah Chow, Margaret M. V. Williams, Maura K. Mack, Rebecca Bellone, Kathryn L. Wotman

Research Article | published 21 Feb 2024 PLOS ONE

https://doi.org/10.1371/journal.pone.0297366

 

Role of in-breeding in pregnancy loss

 A recent study conducted by the Royal Veterinary College (RVC) in collaboration with Cornell University sheds light on the role of inbreeding in mid and late-term pregnancy loss (MLPL) among UK Thoroughbreds. Interestingly, while inbreeding does impact MLPL, it has little effect on early pregnancy loss (EPL).

The research specifically explores the influence of genomic inbreeding levels on late-term pregnancy loss in horses. These findings provide valuable insights for breeding practices, which can help inform mating decisions to reduce the risk of miscarriages in Thoroughbreds.

 

Inbreeding, the mating of related individuals, is a common practice in the livestock industry and can be beneficial in controlled breeding programs for consolidating desirable traits within a population. However, excessive inbreeding heightens the likelihood of producing offspring with harmful homozygous recessive genotypes. This can lead to genetic disorders, reduced fertility, and decreased overall population fitness.

 

Approximately five to ten percent of equine pregnancies result in early pregnancy loss (EPL), while seven percent are lost between Day 70 of gestation and 24 hours postpartum (MLPL). Despite this, prior to this study, there had been no genomic analysis of the correlation between inbreeding levels and pregnancy loss in horses.

 

Led by Dr. Jessica Lawson, Alborada Trust Research Fellow at the RVC, and Professor de Mestre at the Baker Institute for Animal Health at Cornell University, along with former RVC PhD student Dr. Charlotte Shilton, the research team analysed DNA samples from 189 individuals. These samples included allantochorion and foetal DNA from early pregnancy loss (EPL) cases (n=37, gestation age 14–65 days), mid and late-term pregnancy loss (MLPL) cases (n=94, gestational age 70 days–24 hours post parturition), and hair or blood samples from adult UK Thoroughbred controls (n=58).

 

The study revealed that Thoroughbred pregnancies lost in mid and late gestation (MLPL) had significantly higher inbreeding metrics compared to UK Thoroughbred adult controls. Conversely, pregnancies lost early in gestation (EPLs) showed no significant difference in inbreeding metrics compared to controls.

 

These findings emphasise the importance of informed mating decisions in the Thoroughbred breeding industry. Moreover, they stress the need for further research to identify and characterise genomic changes that may prove detrimental to pregnancy.

 

Dr Jessica Lawson, Alborada Trust Research Fellow at the RVC, said: “This research provides critical evidence showing that mating highly related individuals does have a tangible effect on our breeding operations, as there is a real risk of a mare losing her pregnancy late in gestation and failing to produce a foal at all that season. 

 

“The take home from our work should be to carefully consider breeding choices that involve mating of highly related individuals as, ultimately, this may increase the chance of the foal inheriting mutations which may not be compatible with life. We are already working on the next step, looking to identify these changes so more specific advice can be provided in the future”.

 

This research was funded by the Thoroughbred Breeders Association, Horserace Betting Levy Board, the Alborada Trust, and partial PhD studentship funding from the Royal Veterinary College's Paul Mellon Trust for Equine Research.

 

For more details, see: 

Lawson JM, Shilton CA, Lindsay-McGee V, Psifidi A, Wathes DC, Raudsepp T, de Mestre, AM.

Does inbreeding contribute to pregnancy loss in Thoroughbred horses? 

Equine Vet J. 2024.

https://doi.org/10.1111/evj.14057

 

 

Edited press release. Read the original press release:

https://www.rvc.ac.uk/equine-vet/news/new-rvc-research-finds-inbreeding-is-contributing-factor-to-mid-and-late-term-pregnancy-loss-in-thoroughbreds

Effect of punch biopsy on sarcoid growth

 The common belief that taking biopsies of suspected sarcoids could make them worse may not be justified.

 Sarcoids, are the most common skin tumour of horses. Although typically benign, they can be locally aggressive and difficult to manage. They appear in various forms, including flat, nodular, verrucous, fibroblastic, and occult types. Bovine papillomavirus (BPV) has been implicated in the development of sarcoids, although the exact mechanism is not fully understood.

 

In standard veterinary practice, biopsies are a useful diagnostic tool for identifying the nature of swellings and masses. However, the fear of inadvertently worsening the condition has led many veterinarians to avoid biopsy procedures for sarcoids.

 

A recent small-scale study investigating the impact of punch biopsies on the growth of equine sarcoids challenges this assumption. The study failed to confirm the notion that biopsies could exacerbate the aggressiveness or spread of sarcoids.

 

Lien Gysens carried out the study with her colleagues at the Department of Large Animal Surgery, Anaesthesia and Orthopaedics of Domestic Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium. A full rereport of tth research is published in Veterinary Dermatology.

 

The study included six client-owned horses with a total of 11 sarcoids. These horses, all Belgian Warmbloods, presented with a range of clinical types: three occult, four nodular, two verrucous, and two fibroblastic sarcoids.

 

To qualify for inclusion in the study, the horses had to test positive for BPV-1/-2. This was determined using superficial swabs, scrapings, or fine needle aspirates (FNA), which were then subjected to quantitative PCR (qPCR).

 

 The research team examined the dynamics of tumour growth, focusing on factors such as thickness, area, and circumference, as well as viral load (VL) and Visual Analog Scale (VAS) scores in horses affected by sarcoids who underwent a single diagnostic punch biopsy.

 

The growth of each sarcoid was closely monitored on a weekly basis for nine months: from 12 weeks prior to the punch biopsy to 24 weeks following the procedure.

 

In this preliminary study, the researchers didn't find any clear trend in how sarcoids grew after a single punch biopsy. 

 

They observed significant changes in all growth parameters after the biopsy, but there wasn't a consistent direction of change – some grew larger, some smaller, and some stayed the same.

Drawing definite conclusions is challenging due to the limited number of tumours (11 in total) from only six horses with four different types of clinical sarcoids.

 

They conclude: “Our results indicate that post-biopsy lesion deterioration is not a general concept that applies to all sarcoids, and both deterioration or improvement are possible outcomes over a 24-week period. Further clinical studies with a larger sample size are needed before a definitive conclusion can be made.”

 

 

For more details, see:

 

Gysens L,  Martens A,  Haspeslagh M.  

Longitudinal pilot study examining the effect of punch biopsy on equine sarcoid growth dynamics. 

Vet Dermatol.  2024; 35: 148–155.

https://doi.org/10.1111/vde.13236

Collagen link to Thoroughbred fracture risk

 

Recent research conducted by the Royal Veterinary College (RVC) sheds light on the genetic factors contributing to bone fractures in Thoroughbred horses. The study reveals that horses with diminished levels of collagen type III have a higher risk of fractures.

Previously, the underlying genetic mechanisms behind these fractures had remained elusive. However, these new findings have enabled the RVC to identify a novel DNA variant associated with fractures, impacting the expression of collagen type III.

 

Bone fractures are common in Thoroughbred racehorses, due to the forces the bones can experience, and are a leading cause of euthanasia. Approximately 60 horses each year are euthanised on UK racecourses as a result. However, fracture is a complex condition, with both environmental and genetic risk factors affecting a horse’s susceptibility.

Led by Dr. Debbie Guest, Senior Research Fellow at RVC, the team developed a polygenic risk score to gauge disease susceptibility based on various genes. They were then able to use this information to select cells from horses whose risk placed them at the extreme ends of the population with either very low or very high risk. These cells were then used in laboratory studies to establish a cell model and investigate the genetic factors involved in fracture risk.

 

The research team’s findings indicate that bone cells from horses predisposed to fractures express collagen type III at reduced levels due to alterations in their DNA sequence in the region which controls how much collagen III is produced. 

This discovery provides a crucial step forward in identifying genetically high-risk horses. By understanding the genetic causes of fractures,, this research can help identify, diagnose, and manage high-risk horses, improving the health and welfare of Thoroughbreds in the racing industry.

 

Ongoing research aims to validate the risk-scoring system across different horse populations and further explore genetic factors using the established cell model.

 

For more details, see:

 

Palomino Lago, E.; Baird, A.; Blott, S.C.; McPhail, R.E.; Ross, A.C.; Durward-Akhurst, S.A.; Guest, D.J. 

A Functional Single-Nucleotide Polymorphism Upstream of the Collagen Type III Gene Is Associated with Catastrophic Fracture Risk in Thoroughbred Horses. 

Animals 2024, 14, 116. 

https://doi.org/10.3390/ani14010116 

New aid to wound healing?

Polymerisation of the synthetic
epidermis spray (c) Paindaveine et al

Recent research suggests that a synthetic skin spray could aid in wound healing by limiting the
formation of exuberant granulation tissue.  

Due to their nature, horses are prone to injuring themselves. Wounds on the lower legs are particularly likely to heal slowly, often involving exuberant granulation tissue (EGT). This excessive tissue growth, commonly known as "proud flesh," poses a significant challenge to equine wound management, as it hampers further healing by protruding from the wound site. 

 

A team of researchers based in France has been investigating the efficacy of a novel synthetic epidermis spray (SES)* in promoting wound healing. Led by Charlotte C Paindaveine from the Ecole Nationale Vétérinaire de Lyon, the researchers conducted a small-scale clinical trial to compare the healing outcomes of experimental surgical wounds treated with SES spray versus those treated with a standard bandaging technique. 

 

The study, detailed in a report published in PLoS One, involved creating standardised surgical wounds on the lower limbs of six adult Standardbred mares. These wounds were then subjected to treatment with either SES or a traditional bandaging method.

 

Hypergranulation and exudation of
the lateral wounds (right leg) treated
with bandaging, compared with wounds 
on left leg treated with spray.
(c) Paindaveine et al 

For the SES treatment, the spray, which comprised  ultraviolet polymerizable methacrylate monomers, comonomers, crosslinker and a photoinitiator was applied to the wound. The researchers explain that this layer was then polymerised using a 395 nm, 20 x 30 cm, 40 mW/cm2 UV light for 60 seconds at a distance of approximately 30 cm (Fig 1). They repeated the same procedure to fix a second layer of the product. The SES was only applied on day 0. No further application was made.

 

The control treatment consisted of a nonadherent permeable dressing secured with conforming cotton gauze and held in place with a cohesive bandage, which would be a common treatment of choice for superficial wounds in a field setting. The control treatment was repeated every 4 days until the end of the study to mimic field veterinary follow-up.

 

Wounds were assessed daily for the SES treatment group, and every 4 days for the control / bandaged group.

 

The researchers report that the synthetic epidermal spray allowed healing without the production of EGT but it did not reduce the median wound healing time compared to a standard bandaging technique.

 

They add that the exuberant granulation tissue observed in the control group that did not receive the SES decreased without any trimming procedure during the 60-day period.

 

They conclude: “The SES is potentially an interesting alternative for the management of secondary intention wound healing of superficial and non-infected distal limb wounds in adult horses because of its economical and practical aspects. 

 

*Novacika®, Cohesive S.A.S, France

 

 

 

For more details, see: 

 

Charlotte C. Pandaveine, Benoit Bihin, Olivier M. Lepage (2024) 

The effects of a synthetic epidermis spray on secondary intention wound healing in adult horses. PLoS ONE 19(3): e0299990. 

https://doi.org/10.1371/journal.pone.0299990

Effect of antibiotics on gut microbiome

Recent research has shown that even a short course of antibiotics can affect the microorganisms in the
gastrointestinal tract of horses. 

While antibiotics play a vital role in combating infectious ailments, their potential misuse has come under scrutiny, primarily due to concerns surrounding the emergence of antibiotic resistance. Consequently, there's a growing consensus to restrict antibiotic usage to essential cases.

 

Moreover, there's a growing recognition of the susceptibility of the equine gut microbiota to antibiotic-induced disturbances, which can lead to adverse, and occasionally severe, consequences. Although instances of severe, life-threatening diarrhoea in horses post-antibiotic treatment have been infrequent, they highlight the potential risks.

 

Now recent work has shown that even short-term courses of commonly prescribed antibiotics can bring about detectable changes in the gut microbiome.

 

A study conducted by Joseph L Parker from the Gluck Equine Research Center, College of Agriculture, Food, and Environment, University of Kentucky, in collaboration with colleagues, aimed to explore the impact of antibiotic administration on the gut microbiome of healthy horses. They evaluated this impact through assessments of faecal consistency, bacterial population counts, and qPCR panel analysis to detect specific disease-associated organisms.

 

Twenty-four healthy horses, comprising 12 mares and 12 geldings, with no prior exposure to antibiotics or anthelmintic treatment within the preceding three months, were selected for participation in the study. They were grouped into four treatment cohorts, one serving as a control while the others underwent a brief course of distinct antibiotic regimens: potassium penicillin/gentamicin via intravenous injection, ceftiofur via intramuscular injection, and trimethoprim sulphamethoxazole orally.

 

The research team collected faecal samples before treatment began,  on the day after treatment finished, and at 10, 14, 21, and 28 days after the start of treatment. 

 

They found that the response to antibiotic administration varied among the horses. However, all horses administered antibiotics had notably softer faeces compared to the control group. One horse developed severe diarrhoea and was consequently withdrawn from the study.

 

Bacterial population counts revealed that Lactobacillus spp. levels showed a marked reduction in all samples collected from horses the day after antibiotic treatment finished

Furthermore, horses subjected to antibiotic treatment demonstrated a significantly higher likelihood of testing positive for C. difficile or C. perfringens via faecal qPCR analysis.

 

The researchers suggest that more work is needed to explore the consequences of antibiotic-microbiota interactions in the horse.

 

 

For more details, see: 

 

J.L. Parker, A. Page, O. Jacob, V. Stanton, B. Davis, M. Flythe, E.N. Adam,

Equine fecal microbiota response to short term antibiotic administration,

Journal of Equine Veterinary Science (2024) 133, 104993

https://doi.org/10.1016/j.jevs.2023.104993