A novel approach to the use of animals in studies of pain: validation of the canine brief pain inventory in canine bone cancer

Comparison of grapiprant and meloxicam for management of postoperative joint pain in dogs: A randomized, double-blinded, prospective clinical trial

BACKGROUND

Grapiprant is a novel anti-inflammatory drug approved for the treatment of pain associated with osteoarthritis in dogs.

OBJECTIVE

Compare the efficacy of grapiprant vs meloxicam for the management of postoperative joint pain in dogs.

ANIMALS

Forty-eight dogs presented with cranial cruciate ligament disease and treated by tibial plateau leveling osteotomy (TPLO) between May 2020 and May 2022.

METHODS

In this randomized, double blinded, prospective clinical trial, client-owned dogs with naturally occurring unilateral cruciate ligament rupture were enrolled on the day of surgery. The day after surgery, all animals received a subcutaneous injection of 0.2 mg/kg of meloxicam and were randomly assigned to receive either oral grapiprant (2 mg/kg) or meloxicam (0.1 mg/kg), once a day for 14 days, in a blinded manner. The primary endpoint of the study was the pain severity (PSS) and interference (PIS) scores, assessed by the Canine Brief Pain Inventory (CBPI) at day 3, 7, 10 and 15 after the surgery.

RESULTS

Three days after surgery, grapiprant treated dogs had lower PSS compared to meloxicam treated dogs with a mean ± SD of 2.76 ± 0.18 vs 3.25 ± 0.23, respectively (difference of -0.49 [95% CI -0.94 to -0.04], P = .032). Pain Interference Score was also lower in grapiprant group at day 3 (4.11 ± 0.18 vs 4.69 ± 0.16 in meloxicam group [difference of -0.58 {95% CI -1.03 to -0.13}, P = .013]) and at day 10 (2.23 ± 0.13 vs 2.72 ± 0.28 [difference of -0.49 {95% CI -0.92 to -0.01}, P = .049]).

CONCLUSIONS AND CLINICAL IMPORTANCE

Our study supports the use of grapiprant as an alternative analgesic to meloxicam for management of postoperative joint pain in dogs.

Pilot Clinical Trial to Evaluate In Situ Calcium Phosphate Cement Injection for Conservative Surgical Management of Appendicular Osteosarcoma in Dogs

Cementoplasty is a minimally invasive procedure that consists of injecting a bone substitute into the tumor lesion to provide bone reinforcement and alleviate pain. This study aimed to demonstrate the feasibility, safety, and efficacy of cementoplasty with a calcium phosphate cement in osteosarcoma to reduce pain and preserve limb function. Throughout the 6-month study, dogs received no adjuvant therapy, and dogs' evaluations included a clinical examination, monitoring of postoperative complications, radiographic follow-up, and assessment of limb function and pain scores. Out of 12 dogs enrolled, 10 were withdrawn before study completion due to deterioration in their general condition. Nine (9) dogs were followed until D28, six until D56, and two until D183. Compared to D0, more than 50% of the dogs showed improvement in both veterinarian and owner scores at their final visit. Throughout the study, 10 major and 4 minor complications were reported, all unrelated to the procedure. This open non-controlled study provides first evidence of the feasibility, safety, and efficacy of cementoplasty procedure using a calcium phosphate bone cement to relieve pain and preserve limb function in dogs suffering from appendicular osteosarcoma.

Effects of neoadjuvant zoledronate and radiation therapy on cell survival, cell cycle distribution, and clinical status in canine osteosarcoma

Introduction

Zoledronic acid (ZOL) is a third-generation bisphosphonate with a higher affinity for bone resorption areas than earlier bisphosphonates (i.e., pamidronate, PAM). In human medicine, ZOL provides improved bone pain relief and prolonged time to skeletal-related events compared to its older generational counterparts. Preclinical studies have investigated its role as an anti-neoplastic agent, both independently and synergistically, with radiation therapy (RT). ZOL and RT act synergistically in several neoplastic human cell lines: prostate, breast, osteosarcoma, and fibrosarcoma. However, the exact mechanism of ZOL's radiosensitization has not been fully elucidated.

Methods

We investigated ZOL's ability to induce apoptosis in canine osteosarcoma cell lines treated with various doses of megavoltage external beam radiotherapy. Second, we evaluated cell cycle arrest in ZOL-treated cells to assess several neo-adjuvant time points. Finally, we treated 20 dogs with naturally occurring appendicular OS with 0.1 mg/kg ZOL IV 24 h before receiving 8 Gy of RT (once weekly fraction x 4 weeks).

Results

We found that apoptosis was increased in all ZOL-treated cell lines compared to controls, and the combination of ZOL and RT resulted in dissimilar apoptosis between Abrams and D-17 and HMPOS cell lines. Cell cycle arrest (G2/M phase) was minimal and variable between cell lines but perhaps greatest at 48 h post-ZOL treatment. Only 10% of dogs treated with ZOL and RT developed pathologic fractures, compared to 44% of dogs historically treated with PAM and RT (p = 0.027).

Discussion

ZOL and RT appear to be a well-tolerated combination treatment scheme for non-surgical candidates; future studies must elucidate the ideal timing of ZOL.

GenPup-M: A novel validated owner-reported clinical metrology instrument for detecting early mobility changes in dogs

OBJECTIVE

To use a previously validated veterinary clinical examination sheet, Liverpool Osteoarthritis in Dogs (LOAD) questionnaire, combined with kinetic and kinematic gait analysis in dogs with/without mobility problems to demonstrate the capacity of a novel clinical metrology instrument ("GenPup-M") to detect canine mobility impairments.

DESIGN

Quantitative study.

ANIMALS

62 dogs (31 with mobility impairments and 31 without mobility impairments).

PROCEDURE

The dogs' clinical history was obtained from owners and all dogs underwent a validated orthopaedic clinical examination. Mobility impairments were diagnosed in the mobility impaired group based on clinical history and orthopaedic examination. Owners were asked to complete GenPup-M along with a previously validated mobility questionnaire (Liverpool Osteoarthritis in Dogs (LOAD)) to identify construct validity. As a test of criterion validity, the correlation between instrument scores and the overall clinical examination scores, along with force-platform obtained peak vertical forces (PVF) were calculated. GenPup-M underwent internal consistency and factor analysis. Spatiotemporal parameters were calculated for dogs with/without mobility impairments to define the gait differences between these two groups.

RESULTS

Principal Component Analysis identified GenPup-M had two components with Eigenvalues >1 ("stiffness/ease of movement" and "willingness to be active/exercise"). Cronbach's α was used to test internal consistency of GenPup-M and was found to be "good" (0.87). There was a strong, positive correlation between GenPup-M and LOAD responses (r2 = 0.69, p<0.001) highlighting construct validity. Criterion validity was also shown when comparing GenPup-M to clinical examination scores (r2 = 0.74, p<0.001) and PVF (r2 = 0.43, p<0.001). Quantitative canine gait analysis showed that there were statistically significant differences between peak vertical forces (PVF) of mobility impaired and non-mobility impaired dogs (p<0.05). Analyses of PVF showed that non-mobility impaired dogs more evenly distributed their weight across all thoracic and pelvic limbs when compared to mobility impaired dogs. There were also consistent findings that mobility impaired dogs moved slower than non-mobility impaired dogs.

CONCLUSION AND CLINICAL RELEVANCE

GenPup-M is a clinical metrology instrument (CMI) that can be completed by dog owners to detect all mobility impairments, including those that are early in onset, indicating the versatility of GenPup-M to assess dogs with and without mobility impairments. Results of the study found that GenPup-M positively correlated with all three objective measures of canine mobility and consequently showed criterion and construct validity. Owner-reported CMIs such as GenPup-M allow non-invasive scoring systems which veterinary surgeons and owners can use to allow communication and longitudinal assessment of a dog's mobility. It is anticipated that GenPup-M will be used by owners at yearly vaccinations/health checks, allowing identification of any subtle mobility changes, and enabling early intervention.

Longitudinal Analysis of Canine Oral Microbiome Using Whole Genome Sequencing in Aging Companion Dogs

Aged companion dogs have a high prevalence of periodontal disease and canine cognitive dysfunction syndrome (CCDS) and the two disorders are correlated. Similarly, periodontal disease and Alzheimer's Disease are correlated in people. However, little is known about the oral microbiota of aging dogs. The goal of this project was to characterize the longitudinal changes in oral microbiota in aged dogs. Oral swabs were taken from ten senior client-owned dogs on 2-3 occasions spanning 24 months and they underwent whole genome shotgun (WGS) sequencing. Cognitive status was established at each sampling time. A statistically significant increase in alpha diversity for bacterial and fungal species was observed between the first and last study visits. Bacteroidetes and proteobacteria were the most abundant bacterial phyla. Porphyromonas gulae was the most abundant bacterial species (11.6% of total reads). The species Lactobacillus gasseri had a statistically significant increase in relative abundance with age whereas Leptotrichia sp. oral taxon 212 had a statistically significant positive longitudinal association with cognition score. There is an increased fungal and bacterial alpha diversity in aging dogs over time and nearly universal oral dysbiosis. The role of the oral microbiota, particularly Leptotrichia and P. gulae and P. gingivalis, in aging and CCDS warrants further investigation.

An update on mobility assessment of dogs with musculoskeletal disease

Mobility impairments associated with musculoskeletal diseases, such as osteoarthritis and degenerative joint disease, affect approximately 200,000 dogs annually and pose a notable challenge to canine health and welfare. Osteoarthritis causes the remodelling of synovial joints, alongside inflammation and impaired mechanical function which can be extremely debilitating. Secondary osteoarthritis commonly affects dogs and can be exacerbated by previous joint abnormalities, such as patellar luxation or cranial cruciate ligament rupture. Although musculoskeletal diseases can affect dogs of any age, the early subtle signs of gait abnormalities are perhaps missed by owners, thus, dogs may be in the latter stages of osteoarthritis progression when they are presented to veterinarians. Dogs showing subtle signs of gait abnormalities must be presented to veterinary practices for acute diagnosis to prevent long-term deterioration. Musculoskeletal diseases, such as osteoarthritis and degenerative joint disease, are commonly diagnosed via visible radiographic changes. However, veterinarians can use a combination of subjective and objective clinical scoring systems, such as clinical metrology instruments and gait assessment in conjunction with radiography to aid their diagnosis and longitudinal monitoring of musculoskeletal diseases. These scoring systems may be more sensitive to earlier signs of mobility impairments in dogs, ultimately, promoting increased canine health and welfare by enabling pain reduction, improvement of muscle strength and preservation of joint function. Current canine mobility scoring systems available to veterinarians will be discussed in turn throughout this review for implementation into clinical practice.

Translation to Spanish and linguistic validation of the Canine Brief Pain Inventory

Introduction

Pain scales for the assessment of chronic pain have been developed for dogs but they should be translated and linguistically validated to be used by owners with different native languages. The Canine Brief Pain Inventory (CBPI) is widely employed for this purpose but has not been translated into Spanish. Thus, the aim was to produce a validated translation of the Spanish CBPI.

Methods

The original English version of the CBPI was analyzed and translated by two native linguists of the target language and both revised by a third native linguist to identify potential discrepancies and create a unified translation (reconciliation). Then, an independent linguist with native fluency in English and the target language drafted the back-translation. Finally, the research team confronted both the original and the back-translation to identify and solve relevant differences. Once the translated version was produced, a cognitive debriefing was performed to assess the questionnaire in the target population.

Results

A total of 50 surveys were conducted to dog and cat owners of different ages, sex, and socio-economic characteristics. All respondents considered the survey to be clear and a final version of the Spanish CBPI has been produced.

The Science and Social Validity of Companion Animal Welfare: Functionally Defined Parameters in a Multidisciplinary Field

Social validity refers to the social significance and acceptability of intervention goals, procedures, and outcomes. Animal practitioners, who are often guided by the principles of ABA, lack the benefit of verbal participants (at least with respect to target animals) with which to assess a client's needs and preferences. The study of a learner's welfare is useful for determining areas where intervention is needed or how the learner feels about an intervention that is underway. Three tenets of animal welfare measurement include physiological function, naturalistic behavior, and affect, where affect refers to private events, including emotions, which are a function of the same variables and contingencies responsible for controlling public behavior. The development of new technologies allows us to look "under the skin" and account for subjective experiences that can now be observed objectively. We introduce the reader to tools available from the animal welfare sciences for the objective measurement of social validity from the learner's perspective.

Postoperative efficacy of chondroprotectors and diacerein in dogs with osteoarthritis secondary to cranial cruciate ligament disease

Background

Cranial cruciate ligament disease is one of the leading causes of pelvic limb claudication in canines and osteoarthritis in the stifle joint. Historically, studies have focused on surgical options to improve the stability of the stifle joint, although none of the techniques described in the literature prevents the development of osteoarthritis.

Aim

This study aimed at proving the presence of osteoarthritis at the time of diagnosis of cranial cruciate ligament rupture, as well as evaluating the benefits of administering diacerein (DAR) or chondroprotective coadjuvants to the extracapsular fabelo-tibial technique.

Methods

Seventeen dogs aged between 2 and 8, weighing more than 25 kg, with no predilection for breed or sex, were operated on using this technique. These were divided into three groups: DAR, Chondroprotector (CP), and Control. The animals were treated for 90 days and controlled clinically, radiologically, and using multidimensional scales for pain and quality of life. The statistical analysis used was descriptive and through non-parametric tests.

Results

All patients had some degree of osteoarthritis at the beginning of the study associated with the presence of pain. The treated groups improved the claudication scores; however, the changes were significant for the DAR group. The pain score improved in all animals, including those in the Control group; however, the differences were significant only in the treated groups. On the other hand, no significant differences were detected in the radiological studies, so it would be convenient to perform this study over more than 90 days.

Conclusion

The surgical treatment accompanied by drugs that act on the degradation of articular cartilage has better clinical results.

Psychometric properties of the Brazilian version of the Canine Brief Pain Inventory (CBPI) for dogs with clinical signs of osteoarthritis and preliminary evidence of its clinical utility

ABSTRACT This study aimed to determine the psychometric properties and clinical use of the Brazilian version of the Canine Brief Pain Inventory (CBPI) in dogs with hip dysplasia (HD). Forty-three dogs with HD and 16 clinically normal dogs were enrolled. The HD dogs were treated daily with 4.4mg/kg carprofen (GT = 21) or placebo (GP = 19), for four weeks. Owners completed the CBPI at two weeks (W-2) and immediately before the start of the treatment (W0), two (W2) and four (W4) weeks during treatment, and two weeks (W6) after the end of treatment. The internal structure was accessed, and the Cronbach’s alpha coefficient was 0.97, indicating the high internal consistency of the instrument. Principal Component Analysis (PCA) suggested the retention of one component, which accounted for 78% of the variability. The ROC curve analysis concluded that the score 3 has an excellent performance to discriminate between normal and possible HD dogs (AUC of 0.973). There was no difference between dogs treated with carprofen versus placebo. The instrument in Portuguese showed construct and criterion validity and reliability to be used in dogs with HD.

Impact of supplemented undenatured type II collagen on pain and mobility in healthy Labrador Retrievers during an exercise regimen

The aim of this experiment was to evaluate the effect of undenatured type II collagen supplementation on inflammation and pain using gait analysis and industry-accepted pain and mobility questionnaires during an exercise regimen in healthy dogs. Forty healthy Labrador Retrievers (20 male/20 female; range: 5 to 12 yr) were sorted into two groups: undenatured type II collagen group receiving 40 mg UC-II product (10 mg total collagen and ≥3% undenatured type II collagen) and placebo group receiving 40 mg maltodextrin daily by capsule. After 2 wk loading, all dogs began an 11 wk endurance exercise regimen consisting of two weekly runs, starting at 5 km and increasingly incrementally to 8 km, with one final 16 km run. Gait analysis was performed at baseline; before, 24 and 48 h after the first 5 km run; and before, 24 and 48 h after the final 16 km run. Gait analysis was calculated to obtain a Four Rivers Kennel (FRK) Inflammation Index score. Dogs were scored according to the Liverpool Osteoarthritis in Dogs (LOAD) and Canine Brief Pain Inventory (CBPI) assessments at baseline, before and after the first 5 km run, and before and after the final 16 km run. On the LOAD questionnaire, undenatured type II collagen group had improved “how active is the dog” (P = 0.03) and less “stiffness after a lie down” (P = 0.041) compared with placebo at pre 5 km. Undenatured type II collagen appeared to mitigate the development of pain after exercise compared with placebo, as related to the CPBI assessment. Undenatured type II collagen dogs had lower “pain at worst” pre 5 km (P = 0.021), “pain at least” post 5 km (P = 0.015), “pain at average” post 5 km (P = 0.046), and “pain as it is now” post 16 km (P = 0.006) compared with placebo dogs. Undenatured type II collagen was more effective than placebo at mitigating inflammation on gait analysis per the FRK Inflammation Index. Undenatured type II collagen dogs had a 6.42 lower FRK Inflammation Index score at 24 h post 5 km (P = 0.032) and 6.3 lower score at 24 h post 16 km (P = 0.029), indicating the mitigation of inflammation on gait analysis. When considering the change between timepoints, undenatured type II collagen had a lower increase in FRK Inflammation scores compared with placebo for baseline to pre 5 km (P < 0.001), pre 16 km to 24 h post 16 km (P = 0.028), and pre 16 km to 48 h post 16 km (P = 0.027). Undenatured type II collagen supplemented Labrador Retrievers improved pain assessment variables and improved FRK Inflammation Index on gait analysis.

A survey on the orthopedic and functional assessment in a Portuguese population of police working dogs

BACKGROUND

Working dogs are at an increased risk of developing an orthopedic disease compared to companion dogs. This study aimed to evaluate functional and orthopedic index fitness in a Portuguese population of police working dogs. In an observational, prospective study, information on 165 dogs was collected. The age, sex, breed, specific work, and history of previous diagnosis of orthopedic disease were recorded for each patient. A copy of the Canine Orthopedic Index (COI), Hudson Visual Analogue Scale (HVAS), and Functional Assessment (FA) was collected for all dogs. COI, HVAS, and FA scores between breeds, work, age, sex, and history of a previous diagnosis of orthopedic disease were compared. Multiple regression was run to predict COI, HVAS, and FA scores from breeds, work, age, sex, and history of orthopedic disease. Correlations between items were determined with Pearson's correlation. A p < 0.05 was set.

RESULTS

The sample was composed of 92 males and 73 females, with a mean age of 5.2 ± 3.2 years. Four main dog breeds were represented, 60 Belgian Malinois Shepherd Dogs, 52 German Shepherd Dogs, 29 Labrador Retrievers, and 14 Dutch Shepherd Dog. A prevalence of diarrhea of 10.6% was determined, with 4% of dogs having liquid diarrhea. German Shepherd Dogs had significantly higher FA scores (p = 0.03). Dogs with a history of previous veterinary assistance due to orthopedic issues had significantly lower HVAS scores and higher scores with all remaining questionnaires (p < 0.01 for all). No differences were found between sexes or specific work. Age and a history of orthopedic disease contributed to the prediction of all scores. FA scores had a good correlation with COI and HVAS.

CONCLUSION

This population of police working dogs has a good to excellent level of physical fitness. There was a relationship between increasing age, history of orthopedic disease, and worse scores with all questionnaires. All considered questionnaires could differentiate between animals with a previous history of orthopedic disease and sound dogs.

A Pilot Study of Cancer-Induced Bone Pain Using Validated Owner Questionnaires, Serum N-Telopeptide Concentration, Kinetic Analysis, and PET/CT

Cancer-induced bone pain, despite its frequency and severity, is a poorly understood phenomenon in people and animals. Despite excitement regarding translational osteosarcoma studies, there is a lack of attention toward examining cancer pain in dogs. In this pilot study, we used a multimodal pain assessment methodology to evaluate pain relief after therapeutic intervention in dogs with primary bone cancer. We hypothesized that intervention would cause objective evidence of pain relief. Evaluations of 8 dogs with primary bone cancer included ¹⁸F-FDG PET/CT scans, kinetic analysis, validated owner questionnaires (Canine Brief Pain Inventory, canine BPI), and serum N-telopeptide (NTx) concentration. Dogs were routinely staged and had ¹⁸F-FDG PET/CT scans prior to treatment with day 0, 7, 14, and 28 canine BPI, serum NTx, orthopedic exam, and kinetic analysis. Dogs treated with zoledronate and radiation underwent day 28 ¹⁸F-FDG PET scans. All clinical trial work was approved by the University of Missouri IACUC. Four dogs underwent amputation (AMP) for their appendicular bone tumors; four received neoadjuvant zoledronate and hypofractionated radiation therapy (ZOL+RT). Canine BPI revealed significant improvements in pain severity and pain interference scores compared to baseline for all dogs. Positive changes in peak vertical force (+16.7%) and vertical impulse (+29.1%) were noted at day 28 in ZOL+RT dogs. Dogs receiving ZOL+RT had a significant (at least 30%) reduction in serum NTx from baseline compared to amputated dogs (p = 0.029). SUV_max (p = 0.11) and intensity (p = 0.013) values from PET scans decreased while tumor uniformity (p = 0.017) significantly increased in ZOL+RT-treated tumors; gross tumor volume did not change (p = 0.78). Owner questionnaires, kinetic analysis, and ¹⁸F-FDG PET/CT scans showed improved pain relief in dogs receiving ZOL+RT. Serum NTx levels likely do not directly measure pain, but rather the degree of systemic osteoclastic activity. Larger, prospective studies are warranted to identify the ideal objective indicator of pain relief; however, use of multiple assessors is presumably best. With improved assessment of pain severity and relief in dogs with cancer, we can better evaluate the efficacy of our interventions. This could directly benefit people with cancer pain, potentially decreasing the amount of subtherapeutic novel drugs entering human clinical trials.

Evidence-based evaluation of owner-reported outcome measures for canine orthopedic care - a COSMIN evaluation of 6 instruments

OBJECTIVE

To systematically review the currently available validated owner-reported outcome measures (OROMs) for assessing pain and function in dogs with osteoarthritis and other joint diseases.

STUDY DESIGN

Systematic review.

METHODS

A systematic literature search of PubMed and Web of Science was performed in December, 2019, using search terms relevant to OROMs for pain and function in dogs with osteoarthritis and other joint diseases. The measurement properties of the resulting outcome instruments and validation studies were evaluated with the Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN).

RESULTS

Seventeen publications describing the validation of 6 OROMs were selected and evaluated with the COSMIN. The Canine Brief Pain Inventory (CBPI), Canine Orthopedic Index (COI), and Liverpool Osteoarthritis in Dogs (LOAD) provided evidence of sufficient content validity. Internal consistency, reliability, construct validity, and responsiveness were the most frequently validated other properties. Both CBPI and COI had sufficient internal consistency; LOAD, being formative in construct, need not be assessed for internal consistency. No instruments provided information on measurement errors.

CONCLUSION

The CBPI, COI, and LOAD can be recommended for use in dogs with osteoarthritis. Further evidence is necessary to increase the interpretability of these instruments or expand their application into other canine orthopedic conditions. Further evidence is also needed before the other 3 instruments can be recommended.

CLINICAL SIGNIFICANCE

This systematic evaluation of 6 OROMs provides clinicians and researchers with a tool that facilitates and improves evidence-based selection of outcome measures for evaluating canine osteoarthritis and other joint disease treatments.

Linguistic Validation of the Canine Brief Pain Inventory (CBPI) for Global Use

A valid and reliable quantitative measure of chronic pain is essential for developing and evaluating interventions that aim to treat pain. In dogs, the Canine Brief Pain Inventory (CBPI) was originally adapted from a human measure, the Brief Pain Inventory, to assess owner-perceived pain and the impact of such pain on a dog's daily functioning. To be reliable and valid, data collected using a translated instrument should have evidence it is an accurate representation of the original instrument and is culturally appropriate for use in the intended context. To achieve this, instruments should undergo a rigorous translation process and be debriefed in the intended population of use. The CBPI is widely accepted and has been fully validated for use in US-English, Swedish, Italian, and French (France); further translation and validation of the CBPI is required to increase access to and use in other languages and countries. The objective of this study was to linguistically validate the CBPI for global use (Australia, China, Germany, Hungary, Ireland, Japan, Netherlands and Portugal). In cognitive debriefing with a representative sample of dog owners in the target countries it was confirmed that the translations of the CBPI adequately convey the concepts in the original US-English version and that items are easily understood by dog owners. The results of the linguistic validation process thus produced measures that are conceptually equivalent to the original US-English-language CBPI and are culturally appropriate for use in the target countries.

Safety and Clinical Response Following a Repeat Intraarticular Injection of Tin-117m (117mSn) Colloid in Dogs with Elbow Osteoarthritis

Objective

To determine if a repeat intraarticular (IA) injection of a tin-117m colloid radiosynoviorthesis (RSO) agent can be safely given in the same joint 12 months after an initial injection for treatment of canine elbow osteoarthritis (OA), and to evaluate the pain reduction effect of the repeat injection.

Methods and Materials

Nine client owned dogs with grade 1 or 2 elbow OA were given an IA injection of tin-117m colloid in both elbows, one of which had been treated ≤12 months earlier with the same RSO device. Treatment safety was evaluated by joint fluid analysis at baseline (BL) and at 180 days after treatment, and by urinalysis, CBC, and serum chemistry analysis of diagnostic samples obtained at BL and 180 days. Radiographs, computed tomography, and MRI scans were obtained at BL and 180 days to determine if disease progression differed in elbows given one versus two injections. Clinical response to treatment was assessed subjectively by dog owner responses to the Canine Brief Pain Inventory (CBPI) survey at BL, 90 and 180 days, and objectively by investigator-conducted force plate (FP) analysis of dogs at BL, 90, and 180 days.

Results

All post-treatment urinalysis, CBC and clinical chemistry results were within normal ranges. Joint fluid analysis showed a significant (P=0.0411) reduction in the percentage of monocytes at 180 days, consistent with the tin-117m colloid mode of action of apoptosis of pro-inflammatory macrophages at the injection site. There was no significant difference in OA progression in elbows given one or two injections. The treatment success rate was 55.5% (5/9) on day 90 as determined either by CBPI responses or FP analysis, and 66.6% (6/9) on day 180 as determined by FP analysis.

Conclusion

The tin-117m colloid can be safely given as a repeat injection 12 months after an initial injection, and can potentially provide a durable therapeutic response in dogs with elbow OA.

Initial Psychometric Testing and Validation of the Italian Version of the Canine Brief Pain Inventory in Dogs With Pain Related to Osteoarthritis

The Canine Brief Pain Inventory (CBPI) is an owner-administered questionnaire, originally developed and validated in English, used to assess canine chronic pain in terms of severity and interference with daily life activities. The aim of the present study was to perform a preliminary validation of an Italian version of the CBPI. Translation was performed and the resulting questionnaire was administered to 45 native Italian speaking owners of dogs suffering from chronic pain due to radiographically confirmed osteoarthritis. Psychometric properties of the Italian CBPI including construct validity, convergent validity and reliability were evaluated. Construct validity was assessed by factor analysis and confirmed a two-factor model (i.e., pain severity and interference factors). The respective scores, that is, the pain severity score (PSS) and pain interference score (PIS), exhibited a substantial negative correlation with overall quality of life score. Pain severity and interference items showed a mean inter-item correlation of 0.90 and 0.80, respectively. For each question, communality ranged from 0.84 to 0.97, highlighting strong internal consistency and suggesting that PSS and PIS can be calculated by averaging the items contained within each factor. Cronbach's α was 0.97 and 0.96 for PSS and PIS, respectively. The present findings confirmed the main psychometric properties of the Italian version of the CBPI, providing clinicians and researchers with a useful metrology instrument to evaluate the severity of chronic pain and its interference with daily life activities in dogs with osteoarthritis owned by Italian speaking people. Further properties of the questionnaire need to be evaluated in future research and larger studies are warranted.

Pain Treatment in the Companion Canine Model to Validate Rodent Results and Incentivize the Transition to Human Clinical Trials

One of the biggest challenges for analgesic drug development is how to decide if a potential analgesic candidate will work in humans. What preclinical data are the most convincing, incentivizing and most predictive of success? Such a predicament is not unique to analgesics, and the pain field has certain advantages over drug development efforts in areas like neuropsychiatry where the etiological origins are either unknown or difficult to ascertain. For pain, the origin of the problem frequently is known, and the causative peripheral tissue insult might be observable. The main conundrum centers around evaluation of translational cell- and rodent-based results. While cell and rodent models are undeniably important first steps for screening, probing mechanism of action, and understanding factors of adsorption, distribution metabolism and excretion, two questions arise from such studies. First, are they reliable indicators of analgesic performance of a candidate drug in human acute and chronic pain? Second, what additional model systems might be capable of increasing translational confidence? We address this second question by assessing, primarily, the companion canine model, which can provide particularly strong predictive information for candidate analgesic agents in humans. This statement is mainly derived from our studies with resiniferatoxin (RTX) a potent TRPV1 agonist but also from protein therapeutics using a conjugate of Substance P and saporin. Our experience, to date, is that rodent models might be very well suited for acute pain translation, but companion canine models, and other large animal studies, can augment initial discovery research using rodent models for neuropathic or chronic pain. The larger animal models also provide strong translational predictive capacity for analgesic performance in humans, better predict dosing parameters for human trials and provide insight into behavior changes (bladder, bowel, mood, etc.) that are not readily assessed in laboratory animals. They are, however, not without problems that can be encountered with any experimental drug treatment or clinical trial. It also is important to recognize that pain treatment is a major veterinary concern and is an intrinsically worthwhile endeavor for animals as well as humans.

Treatment response in dogs with naturally occurring grade 3 elbow osteoarthritis following intra-articular injection of 117mSn (tin) colloid

The radionuclide ^117mSn (tin-117m) embedded in a homogeneous colloid is a novel radiosynoviorthesis (RSO) device for intra-articular (IA) administration to treat synovial inflammation and mitigate osteoarthritis (OA) in dogs. A study to evaluate tin-117m colloid treatment response in dogs with OA was conducted at two centers, the School of Veterinary Medicine at Louisiana State University, and at a referral practice in Houston, Texas. The tin-117m colloid was administered per-protocol to 14 client-owned dogs with radiographically confirmed, grade 3 OA in one or both elbow joints. Dog owners and attending clinicians assessed the level of pain at baseline (BL) and the post-treatment pain response at 90-day intervals for one year. Owners assessed treatment response according to a pain severity score (PSS) and a pain interference score (PIS) as defined by the Canine Brief Pain Inventory. Clinicians reported a lameness score using a 0–5 scale, from no lameness to continuous non-weight bearing lameness, when observing dogs at a walk and a trot. The rate of treatment success as determined by improved mean PSS and PIS scores reported by dog owners was >70% at all time points. Clinicians reported an improved mean pain score from BL at post-treatment Days 90 (p<0.05), 180, and 270. The dog owner and clinician assessments of treatment success were significantly correlated (p>0.05) at Day 90 and Day 180 time points. Results indicated that a single IA dose of tin-117m colloid provided a significant reduction in pain and lameness and improved functionality for up to a full year, with no adverse treatment related effects, in a high percentage of dogs with advanced, clinical OA of the elbow joint.

Comparison of Two Mesotherapy Protocols in the Management of Back Pain in Police Working Dogs: A Retrospective Study

This study aimed to compare 2 protocols for the management of back pain in police working dogs. Twenty animals were signaled based on history, trainer complaints, physical and radiographic examination consistent with back pain. In a retrospective study, 2 groups were considered: GM, treated with a solution comprising a combination of lidocaine, dexamethasone, and tiocolchicoseide; and GT, treated with the same solution, with the addition of Traumeel LT. Response to treatment, measured by the Canine Brief Pain Inventory (CBPI, divided into pain interference score - PIS, and pain severity score - PSS) and Hudson Visual Analogue Scale (HVAS), was evaluated before treatment (T0), after 15 (+15d) days and 1 (+30d), 2 (+60d), 3 (+90d), 4 (+120d), 5 (+150d) and 6 (+180d) months. Results were compared using an independent samples t-test or a Paired Samples t-test. Comparing results for each moment with T0 within each group, differences where observed only in GM at +15d (P < .01 for PIS and P < .01 for PSS), +30d (P = .04 for PIS and P < .01 for PSS), +60d (P = .03 for PIS and P = .02 for PSS) and +90d (P = .02 for PSS). Treatment was successful in reducing PSS (reduction of ≥1) in 8/10 animals of GM at +15d (80%), 8/10 at +30d (80%), 5/10 at +60d (50%), 4/10 at +90d (40%), 3/9 at +120d (33.3%) and 2/9 at +150d -+ 180d (22.2%). In GT, treatment was successful in 1/10 at +15d -+30d (10%), 2/10 at +60d (20%) and 1/10 at +90d (10%). No differences were observed with HVAS any time point for either intervention or when comparing groups in each moment. The protocol used in GM produced significant improvements, while the addition of Traumeel did not, rather reducing the effect of treatment in working dogs with back pain. Further studies are required.

Spontaneous and Induced Animal Models for Cancer Research

Considering the complexity of the current framework in oncology, the relevance of animal models in biomedical research is critical in light of the capacity to produce valuable data with clinical translation. The laboratory mouse is the most common animal model used in cancer research due to its high adaptation to different environments, genetic variability, and physiological similarities with humans. Beginning with spontaneous mutations arising in mice colonies that allow for pursuing studies of specific pathological conditions, this area of in vivo research has significantly evolved, now capable of generating humanized mice models encompassing the human immune system in biological correlation with human tumor xenografts. Moreover, the era of genetic engineering, especially of the hijacking CRISPR/Cas9 technique, offers powerful tools in designing and developing various mouse strains. Within this article, we will cover the principal mouse models used in oncology research, beginning with behavioral science of animals vs. humans, and continuing on with genetically engineered mice, microsurgical-induced cancer models, and avatar mouse models for personalized cancer therapy. Moreover, the area of spontaneous large animal models for cancer research will be briefly presented.

Oral Transmucosal Cannabidiol Oil Formulation as Part of a Multimodal Analgesic Regimen: Effects on Pain Relief and Quality of Life Improvement in Dogs Affected by Spontaneous Osteoarthritis

Simple Summary

Osteoarthritis is a progressive and degenerative condition that affects dog populations, causing pain. The pain associated with osteoarthritis is considered to be chronic, owing to both active inflammation and to a maladaptive component caused by central sensitization. Chronic pain in dogs is being increasingly recognised as a significant problem, and finding successful treatments against canine osteoarthritis-related pain is challenging. The aim of this study was to assess the efficacy in pain management over a twelve-week period of oral transmucosal cannabidiol, in combination with a multimodal pharmacological protocol, in dogs affected by spontaneous osteoarthritis. Dogs receiving oral transmucosal cannabidiol in addition to an anti-inflammatory drug, gabapentin and amitriptyline showed a meaningful improvement in Canine Brief Pain Inventory scores, in comparison with dogs that did not receive cannabidiol. The present study suggests that the addition of oral transmucosal cannabidiol to a multimodal pharmacological treatment for canine osteoarthritis improves owner reported pain scores and quality of life of dogs, without severe adverse effects.

Abstract

The aim of this study was to evaluate the efficacy of oral transmucosal (OTM) cannabidiol (CBD), in addition to a multimodal pharmacological treatment for chronic osteoarthritis-related pain in dogs. Twenty-one dogs were randomly divided into two groups: in group CBD (n = 9), OTM CBD (2 mg kg⁻¹ every 12 h) was included in the therapeutic protocol (anti-inflammatory drug, gabapentin, amitriptyline), while in group C (n = 12), CBD was not administered. Dogs were evaluated by owners based on the Canine Brief Pain Inventory scoring system before treatment initiation (T0), and one (T1), two (T2), four (T3) and twelve (T4) weeks thereafter. Pain Severity Score was significantly lower in CBD than in C group at T1 (p = 0.0002), T2 (p = 0.0043) and T3 (p = 0.016). Pain Interference Score was significantly lower in CBD than in C group at T1 (p = 0.0002), T2 (p = 0.0007) and T4 (p = 0.004). Quality of Life Index was significantly higher in CBD group at T1 (p = 0.003). The addition of OTM CBD showed promising results. Further pharmacokinetics and long-term studies in larger populations are needed to encourage its inclusion into a multimodal pharmacological approach for canine osteoarthritis-related pain.

Impact of breed on canine humeral condylar fracture configuration, surgical management, and outcome

OBJECTIVE

To report the prevalence, configuration, risk factors, fixation methods and outcomes after repair of humeral condylar fractures (HCF) in dogs.

STUDY DESIGN

Retrospective nested cohort study.

SAMPLE POPULATION

One hundred twelve dogs.

METHODS

Medical records of dogs referred between January 2010 and August 2018 were searched for HCF. Demographics, fracture configuration, repair, and complications were obtained from medical records. Radiographs were assessed for fracture reduction, implant positioning, and bone healing. Short-term radiographic and clinical outcomes, and long-term owner-assessed outcome was determined. Associations between these variables were statistically analyzed.

RESULTS

Dogs with HCF represented 112 of 43 325 (0.26%, 95% CI 0.22-0.31) referrals. French bulldogs and spaniel breeds were predisposed to HCF (P < .02). French bulldogs were 6.58 times (95% CI 1.62-26.7) more likely than other breeds to have a medial HCF (P = .008). Epicondylar plate fixation was associated with reduced complications compared with lag screws and Kirschner wires (P = .009). Lameness was scored as 1 of 5 (median) in the 85 dogs with initial follow-up (median 6 weeks) after HCF repair. Outcome was considered excellent in 26 of 31 dogs with long-term follow-up (median 36 months).

CONCLUSION

French bulldogs and spaniels were predisposed to HCF, and medial HCF were more common in French bulldogs. Epicondylar plate fixation was associated with reduced complications.

CLINICAL SIGNIFICANCE

French bulldogs are predisposed to HCF, including medial HCF. Epicondylar plate fixation is recommended over other epicondylar fixation methods to reduce complications.

Spontaneous dog osteoarthritis - a One Medicine vision

Osteoarthritis (OA) is a global disease that, despite extensive research, has limited treatment options. Pet dogs share both an environment and lifestyle attributes with their owners, and a growing awareness is developing in the public and among researchers that One Medicine, the mutual co-study of animals and humans, could be beneficial for both humans and dogs. To that end, this Review highlights research opportunities afforded by studying dogs with spontaneous OA, with a view to sharing this active area of veterinary research with new audiences. Similarities and differences between dog and human OA are examined, and the proposition is made that suitably aligned studies of spontaneous OA in dogs and humans, in particular hip and knee OA, could highlight new avenues of discovery. Developing cross-species collaborations will provide a wealth of research material and knowledge that is relevant to human OA and that cannot currently be obtained from rodent models or experimentally induced dog models of OA. Ultimately, this Review aims to raise awareness of spontaneous dog OA and to stimulate discussion regarding its exploration under the One Medicine initiative to improve the health and well-being of both species.

Osteoarthritis occurs spontaneously in pet dogs, which often share environmental and lifestyle risk-factors with their owners. This Review aims to stimulate cooperation between medical and veterinary research under the One Medicine initiative to improve the welfare of dogs and humans.

Dogs have many analogous spontaneous diseases that result in end-stage osteoarthritis (OA).

Inbreeding and the predisposition of certain dog breeds for OA enable easier identification of candidate genetic associations than in outbred humans.

Dog OA subtypes offer a potential stratification rationale for aetiological differences and alignment to analogous human OA phenotypes.

The relatively compressed time course of spontaneous dog OA offers longitudinal research opportunities.

Collaboration with veterinary researchers can provide tissue samples from early-stage OA and opportunities to evaluate new therapeutics in a spontaneous disease model.

Awareness of the limitations and benefits of using clinical veterinary patients in research is important.

Biocompatibility of allogenic canine fascia lata: In vitro evaluation and small case series

OBJECTIVE

To evaluate the biocompatibility of canine fascia lata (FL) in vitro and after FL allograft implantation in dogs with clinical disease.

STUDY DESIGN

In vitro experiment and small case series.

SAMPLE POPULATION

Six dogs treated with allogenic freeze-dried FL.

METHODS

Fibroblasts were cultured on disks of FL, polypropylene mesh (PM; negative control), and porcine small intestinal submucosa (SIS; positive control). Constructs were compared at 3, 7, and 14 days for water content, DNA amounts, scanning electron microscopy, and histology. Records of dogs treated with FL allografts with follow-up examination were reviewed for signalment, indication for surgery, surgical procedure, and outcomes. All owners were invited to complete a standardized questionnaire for long-term follow-up.

RESULTS

Water content was greater in FL and SIS than in PM (P = .03). Fascia lata constructs contained more DNA compared with PM constructs at days 7 and 14 (P < .05), whereas SIS constructs did not differ from FL or PM. Fibroblasts appeared spherical and distributed throughout FL constructs, whereas they appeared stellate and remained on the surface of SIS and PM. Fascia lata allografts were implanted in six dogs with surgical conditions. No incisional complications were noted. All dogs had good to excellent long-term outcomes, except one that experienced recurrence of a perineal hernia 2 years after repair.

CONCLUSION

In vitro, canine FL allowed attachment and proliferation of fibroblasts throughout layers of the graft. Canine allogenic FL was clinically well tolerated in this small population of dogs.

CLINICAL SIGNIFICANCE

Allogenic FL is biocompatible and can be considered an alternative to SIS for soft tissue augmentation in dogs.

Retrospective survey of owners' experiences with palliative radiation therapy for pets

OBJECTIVE To describe animal owners' experiences with palliative radiation therapy (PRT) of pets and identify factors influencing satisfaction with their pets' treatment. DESIGN Retrospective, cross-sectional study. SAMPLE 118 owners of dogs, cats, or rabbits. PROCEDURES Medical records were searched to identify animals that underwent PRT between 2004 and 2013. Signalment, tumor-related data, and outcome information were recorded. Owners completed an electronic survey assessing satisfaction with treatment (ie, satisfaction with the decision for their pet to undergo PRT and indication that they would choose PRT for their pet again), expectations regarding PRT, and perceptions of their pets' quality of life (QOL) and signs of discomfort from acute adverse radiation effects. Additional data regarding practical aspects of treatment, pet death, communications with veterinarians, and owner demographics were collected. Variables were tested for association with measures of owner satisfaction. RESULTS 92 of 116 (79%) owners were satisfied with the decision to have their pets undergo PRT. Most (92/118 [78%]) owners reported their pet's QOL improved after PRT; these owners were significantly more likely to be satisfied than those who did not report improved QOL. Owners who perceived their pets had discomfort from adverse radiation effects (38/116 [33%]) were significantly less likely to be satisfied than owners who did not report this observation. Measures of satisfaction were not associated with patient survival time. Twenty-one of 118 (18%) owners indicated they expected PRT would cure their pet's tumor. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that short life expectancy should not deter recommendation of PRT for pets. Protocols that minimize risk of acute adverse effects may be advantageous. Veterinarians should attempt to ensure that owners understand the goals of PRT.

Initial psychometric testing and validation of the French version of the Canine Brief Pain Inventory

OBJECTIVE

The Canine Brief Pain Inventory (CBPI) is an owner-completed questionnaire quantifying the severity and impact of chronic pain in dogs. The English version of the CBPI was adapted into French and the objective of this study was to validate this French version of the CBPI.

STUDY DESIGN

Prospective clinical study.

ANIMALS

A group of 32 dogs with a medical history, clinical signs and radiographic evidence consistent with osteoarthritis.

METHODS

Owners of dogs with osteoarthritis who were native French speakers completed a single administration of the translated questionnaire. The psychometric properties were evaluated including construct validity (by factor analysis), reliability (internal consistency) and convergent validity.

RESULTS

Factor analysis on the responses from this cohort confirmed a two-factor questionnaire: the Pain Severity (PS) factor and the Pain Interference (PI) factor. The mean inter-item correlation for PS and PI questions was 0.74 and 0.53, respectively. These findings reveal strong internal consistency, suggesting that the questions contained within each factor measure the same concept and can be pooled to generate the PS score (PSS) and PI score (PIS). Cronbach's α was 0.91 and 0.87 for PSS and PIS, respectively. There was strong negative correlation between PSS and PIS with the overall quality of life score (r = -0.62 and r = -0.79, respectively, with p < 0.001 for both), consistent with the hypothesis that increases in PS and PS with function are highly correlated with a corresponding decrease in overall quality of life.

CONCLUSIONS AND CLINICAL RELEVANCE

Initial validation of this French version of the CBPI represents an important step in the expanded use of validated owner-completed outcome assessment instruments for use by researchers and clinicians who seek reliable methods to quantify the severity and impact of chronic pain in dogs with osteoarthritis.

Development and psychometric testing of the Canine Owner-Reported Quality of Life questionnaire, an instrument designed to measure quality of life in dogs with cancer

OBJECTIVE To describe development and initial psychometric testing of an owner-reported questionnaire designed to standardize measurement of general quality of life (QOL) in dogs with cancer. DESIGN Key-informant interviews, questionnaire development, and field trial. SAMPLE Owners of 25 dogs with cancer for item development and pretesting and owners of 90 dogs with cancer for reliability and validity testing. PROCEDURES Standard methods for development and testing of questionnaire instruments intended to measure subjective states were used. Items were generated, selected, scaled, and pretested for content, meaning, and readability. Response items were evaluated with exploratory factor analysis and by assessing internal consistency (Cronbach α) and convergence with global QOL as determined with a visual analog scale. Preliminary tests of stability and responsiveness were performed. RESULTS The final questionnaire-which was named the Canine Owner-Reported Quality of Life (CORQ) questionnaire-contained 17 items related to observable behaviors commonly used by owners to evaluate QOL in their dogs. Several items pertaining to physical symptoms performed poorly and were omitted. The 17 items were assigned to 4 factors-vitality, companionship, pain, and mobility-on the basis of the items they contained. The CORQ questionnaire and its factors had high internal consistency (Cronbach α = 0.68 to 0.90) and moderate to strong correlations (r = 0.49 to 0.71) with global QOL as measured on a visual analog scale. Preliminary testing indicated good test-retest reliability and responsiveness to improvements in overall QOL. CONCLUSIONS AND CLINICAL RELEVANCE The CORQ questionnaire was a valid, reliable owner-reported questionnaire that measured general QOL in dogs with cancer and showed promise as a clinical trial outcome measure for quantifying changes in individual dog QOL occurring in response to cancer treatment and progression.

Long-term pain relief in canine osteoarthritis by a single intra-articular injection of resiniferatoxin, a potent TRPV1 agonist

The translational potential of analgesic approaches emerging from basic research can be augmented by client-owned dog trials. We report on a peripheral interventional approach that uses intra-articular injection of the ultrapotent TRPV1 agonist resiniferatoxin (RTX) to produce a selective long-term chemoinactivation of nociceptive primary afferent nerve endings for pain control in naturally occurring canine osteoarthritis. A single injection of 10 µg of RTX, produced suppression of pain, improvement in gait, weight bearing, and improvement in the dog's activities of daily living lasting 4 months or longer. Two to 3 years after the injection, there are no alterations to suggest that removal of inflammatory pain caused accelerated joint degeneration (Charcot joint) in any of the dogs. To amplify the effective use of canine subjects in translational analgesia research, we report a high-quality canine dorsal root ganglion transcriptome. Some targets for analgesia are highly conserved both in protein sequence and level of expression within a target tissue while others diverge substantially from the human. This knowledge is especially important for development of analgesics aimed at peripheral molecular targets and provides a template for informed translational research. The peripheral site of action, long duration of analgesia, apparent safety, and retention of coordination, all resulting from a single dose suggest that intra-articular RTX may be an effective intervention for osteoarthritis pain with few or no side effects and lead to an improved quality of life.

Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events: Methods for item selection in industry-sponsored oncology clinical trials

As new cancer treatment regimens demonstrate increased potential to improve patients' survival, more focus is directed toward the quality of that extension of life and to obtaining additional information from patients regarding their experience with treatment. The utility of capturing patient-reported treatment-related symptoms to complement traditional clinician-rated symptomatic adverse event reporting is well-documented. The National Cancer Institute's Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events is an item library aimed at capturing patient-reported symptoms to inform the patient perspective on a treatment's tolerability. The U.S. Food and Drug Administration has recommended using the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events in clinical trials. A practical guideline is needed to inform a priori selection of specific Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events items for use in any given industry-sponsored oncology clinical trial. Standardizing this selection process will foster systematic and consistent data collection as part of drug development and enhance our knowledge on how to use patient-relevant information as part of a treatment's risk/benefit assessment. This article presents methods and consensus recommendations for selecting specific Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events items to include in early-phase and late-phase oncology clinical trials.

Assessment of quality of life and chronic pain in dogs

Assessment of chronic pain and quality of life (QOL) are integral to clinical veterinary research and practice, and recent years have seen an increase in the published tools available for the assessment of both. However, the relationship between chronic pain and QOL in veterinary patients has received insufficient attention. This narrative review for the first time explores similarities, differences and interactions between chronic pain and quality of life and identifies common challenges to their assessment in dogs. In the opinion of these authors, assessments of both chronic pain and quality of life should be pro-active, global, regular, applied to answer specific questions for researchers and decision makers, and transparent about what has, and has not, been assessed. Collaboration in this field between animal welfare scientists, veterinary researchers and clinicians appears rare, and should be prioritised.

Translational pain assessment: could natural animal models be the missing link?

Failure of analgesic drugs in clinical development is common. Along with the current "reproducibility crisis" in pain research, this has led some to question the use of animal models. Experimental models tend to comprise genetically homogeneous groups of young, male rodents in restricted and unvarying environments, and pain-producing assays that may not closely mimic the natural condition of interest. In addition, typical experimental outcome measures using thresholds or latencies for withdrawal may not adequately reflect clinical pain phenomena pertinent to human patients. It has been suggested that naturally occurring disease in veterinary patients may provide more valid models for the study of painful disease. Many painful conditions in animals resemble those in people. Like humans, veterinary patients are genetically diverse, often live to old age, and enjoy a complex environment, often the same as their owners. There is increasing interest in the development and validation of outcome measures for detecting pain in veterinary patients; these include objective (eg, locomotor activity monitoring, kinetic evaluation, quantitative sensory testing, and bioimaging) and subjective (eg, pain scales and quality of life scales) measures. Veterinary subject diversity, pathophysiological similarities to humans, and diverse outcome measures could yield better generalizability of findings and improved translation potential, potentially benefiting both humans and animals. The Comparative Oncology Trial Consortium in dogs has pawed the way for translational research, surmounting the challenges inherent in veterinary clinical trials. This review describes numerous conditions similarly applicable to pain research, with potential mutual benefits for human and veterinary clinicians, and their respective patients.

Pain control through selective chemo-axotomy of centrally projecting TRPV1+ sensory neurons

Agonists of the vanilloid receptor transient vanilloid potential 1 (TRPV1) are emerging as highly efficacious nonopioid analgesics in preclinical studies. These drugs selectively lesion TRPV1+ primary sensory afferents, which are responsible for the transmission of many noxious stimulus modalities. Resiniferatoxin (RTX) is a very potent and selective TRPV1 agonist and is a promising candidate for treating many types of pain. Recent work establishing intrathecal application of RTX for the treatment of pain resulting from advanced cancer has demonstrated profound analgesia in client-owned dogs with osteosarcoma. The present study uses transcriptomics and histochemistry to examine the molecular mechanism of RTX action in rats, in clinical canine subjects, and in 1 human subject with advanced cancer treated for pain using intrathecal RTX. In all 3 species, we observe a strong analgesic action, yet this was accompanied by limited transcriptional alterations at the level of the dorsal root ganglion. Functional and neuroanatomical studies demonstrated that intrathecal RTX largely spares susceptible neuronal perikarya, which remain active peripherally but unable to transmit signals to the spinal cord. The results demonstrate that central chemo-axotomy of the TRPV1+ afferents underlies RTX analgesia and refine the neurobiology underlying effective clinical use of TRPV1 agonists for pain control.

Clinical outcome and complications of thoracic and pelvic limb stump and socket prostheses

Objectives: To describe the use, quality of life, compliance, complications, and outcome of animals fitted with stump socket prostheses.

Methods: Medical records of dogs fitted with a stump socket prosthesis were reviewed. Functional outcome, quality of life and complications were retrospectively assessed from an owner questionnaire.

Results: Thirteen stump socket prostheses (12 dogs) were fitted for a variety of reasons including trauma, congenital abnormalities, and neoplasia. Eight dogs had a good outcome overall and four a poor outcome. Quality of life (QOL) remained good or excellent in 10/12 dogs. Nine complications were seen in 7/12 dogs, most were manageable; surgical wound complications (n = 2) and pressures sores (n = 4) were the most frequently encountered. One dog suffered multiple complications. Thoracic and pelvic limb stump socket prostheses had a similar complication rate, however all animals with a poor outcome had a thoracic limb stump socket prosthesis; two were small breed dogs (under 10 kg) and two had bilateral thoracic limb abnormalities.

Clinical significance: Stump socket prostheses are feasible and versatile in animals. In correctly selected cases, good to excellent outcomes are possible. However, complications are frequent but often manageable. Further investigations are required into the risk factors for poor outcomes and prospective studies are required to assess changes in biomechanics, function, and QOL before and after fitting of a stump socket prosthesis. Until further evidence is available, careful consideration should be given before fitting bilateral thoracic limb stump socket prostheses or thoracic limb stump socket prostheses to small breed dogs.

Supplementary Material to this article is available online at https://doi.org/10.3415/VCOT-16-09-0127

Psychometric evaluation of the canine brief pain inventory in a Swedish sample of dogs with pain related to osteoarthritis

BACKGROUND

To evaluate intervention, implement evidence-based practice and enhance the welfare of dogs with naturally occurring osteoarthritis (OA), access to valid, reliable and clinically relevant outcome measures is crucial for researchers, veterinarians and rehabilitation practitioners. The objectives of the present study were to translate and evaluate psychometric properties, in terms of internal consistency and construct validity, of the owner-reported measure canine brief pain inventory (CBPI) in a Swedish sample of dogs with pain related to OA.

RESULTS

Twenty-one owners of clinically sound dogs and 58 owners of dogs with pain related to OA were included in this observational and cross-sectional study. After being translated according to the guidelines for patient-reported outcome measures, the CBPI was completed by the canine owners. Construct validity was assessed by confirmatory factor analysis, by repeating the principal component analysis and by assessing for differences between clinically sound dogs and dogs with pain related to OA. Internal consistency was estimated by Cronbach's α. Confirmatory factor analysis was not able to confirm the factor-structure models tested in our sample. Principal component analysis showed a two-component structure, pain severity and pain interference of function. Two components accounted for 76.8% of the total variance, suggesting an acceptable fit of a two-component structure. The ratings from the clinically sound dogs differed from OA dogs and showed significantly lower CBPI total sum. Cronbach's α was 0.94 for the total CBPI, 0.91 for the pain severity and 0.91 for the pain interference of function.

CONCLUSIONS

The results indicate that the translated version of the CBPI is valid for use in the Swedish language. The findings suggest satisfying psychometric properties in terms of high internal consistencies and ability to discriminate clinically sound dogs from OA dogs. However, based on the confirmatory factor analysis, the original factor structure in the CBPI is not ideally suited to measure pain related to OA in our sample and the hypothesis of the presented two-factor structure was rejected. Further research needs to be conducted to determine whether the original psychometric results from CBPI can be replicated across different target groups and particularly with larger sample size.

Suppression of Canine Dendritic Cell Activation/Maturation and Inflammatory Cytokine Release by Mesenchymal Stem Cells Occurs Through Multiple Distinct Biochemical Pathways

Mesenchymal stem cells (MSC) represent a readily accessible source of cells with potent immune modulatory activity. MSC can suppress ongoing inflammatory responses by suppressing T cell function, while fewer studies have examined the impact of MSC on dendritic cell (DC) function. The dog spontaneous disease model represents an important animal model with which to evaluate the safety and effectiveness of cellular therapy with MSC. This study evaluated the effects of canine MSC on the activation and maturation of canine monocyte-derived DC, as well as mechanisms underlying these effects. Adipose-derived canine MSC were cocultured with canine DC, and the MSC effects on DC maturation and activation were assessed by flow cytometry, cytokine ELISA, and confocal microscopy. We found that canine MSC significantly suppressed lipopolysaccharide (LPS)-stimulated upregulation of DC activation markers such as major histocompatibility class II (MHCII), CD86, and CD40. Furthermore, pretreatment of MSC with interferon gamma (IFNγ) augmented this suppressive activity. IFNγ-activated MSC also significantly reduced LPS-elicited DC secretion of tumor necrosis factor alpha without reducing secretion of interleukin-10. The suppressive effect of IFNγ-treated MSC on LPS-induced DC activation was mediated by soluble factors secreted by both MSC and DC. Pathways of DC functional suppression included programmed death ligand-1 expression and secretion of nitrous oxide, prostaglandin E2, and adenosine by activated MSC. Coculture of DC with IFNγ-treated MSC maintained DC in an immature state and prolonged DC antigen uptake during LPS maturation stimulus. Taken together, canine MSC are capable of potently suppressing DC function in a potentially inflammatory microenvironment through several separate immunological pathways and confirm the potential for immune therapy with MSC in canine immune-mediated disease models.

Functional outcome measures in a surgical model of hip osteoarthritis in dogs

Background

The hip is one of the most common sites of osteoarthritis in the body, second only to the knee in prevalence. However, current animal models of hip osteoarthritis have not been assessed using many of the functional outcome measures used in orthopaedics, a characteristic that could increase their utility in the evaluation of therapeutic interventions. The canine hip shares similarities with the human hip, and functional outcome measures are well documented in veterinary medicine, providing a baseline for pre-clinical evaluation of therapeutic strategies for the treatment of hip osteoarthritis. The purpose of this study was to evaluate a surgical model of hip osteoarthritis in a large laboratory animal model and to evaluate functional and end-point outcome measures.

Methods

Seven dogs were subjected to partial surgical debridement of cartilage from one femoral head. Pre- and postoperative pain and functional scores, gait analysis, radiographs, accelerometry, goniometry and limb circumference were evaluated through a 20-week recovery period, followed by histological evaluation of cartilage and synovium.

Results

Animals developed histological and radiographic evidence of osteoarthritis, which was correlated with measurable functional impairment. For example, Mankin scores in operated limbs were positively correlated to radiographic scores but negatively correlated to range of motion, limb circumference and 20-week peak vertical force.

Conclusions

This study demonstrates that multiple relevant functional outcome measures can be used successfully in a large laboratory animal model of hip osteoarthritis. These measures could be used to evaluate relative efficacy of therapeutic interventions relevant to human clinical care.

Electronic supplementary material

The online version of this article (doi:10.1186/s40634-016-0053-5) contains supplementary material, which is available to authorized users.

Resiniferatoxin: The Evolution of the "Molecular Scalpel" for Chronic Pain Relief

Control of chronic pain is frequently inadequate or can be associated with debilitating side effects. Ablation of certain nociceptive neurons, while retaining all other sensory modalities and motor function, represents a new therapeutic approach to controlling severe pain while avoiding off-target side effects. transient receptor potential cation channel subfamily V member 1 (TRPV1) is a calcium permeable nonselective cation channel expressed on the peripheral and central terminals of small-diameter sensory neurons. Highly selective chemoablation of TRPV1-containing peripheral nerve endings, or the entire TRPV1-expressing neuron itself, can be used to control chronic pain. Administration of the potent TRPV1 agonist resiniferatoxin (RTX) to neuronal perikarya or nerve terminals induces calcium cytotoxicity and selective lesioning of the TRPV1-expressing nociceptive primary afferent population. This selective neuroablation has been coined "molecular neurosurgery" and has the advantage of sparing motor, proprioceptive, and other somatosensory functions that are so important for coordinated movement, performing activities of daily living, and maintaining quality of life. This review examines the mechanisms and preclinical data underlying the therapeutic use of RTX and examples of such use for the management of chronic pain in clinical veterinary and human pain states.

Intrathecal resiniferatoxin in a dog model: efficacy in bone cancer pain

Resiniferatoxin (RTX) is the most potent among all known endogenous and synthetic agonists for the transient receptor potential vanilloid 1 (TRPV1) receptor, which is a calcium-permeable nonselective cation channel, expressed on the peripheral and central terminals of small-diameter sensory neurons. Prolonged calcium influx induced by RTX causes cytotoxicity and death of only those sensory neurons that express the TRPV1 ion channel leading to selective targeting and permanent deletion of the TRPV1-expressing C-fiber neuronal cell bodies in the dorsal root ganglia. The goal of this project was to provide preclinical efficacy data, that intrathecal RTX could provide effective pain relief and improve function in dogs with bone cancer without significant long-term side effects. In a single-blind, controlled study, 72 companion dogs with bone cancer pain were randomized to standard of care analgesic therapy alone (control, n = 36) or 1.2 μg/kg intrathecal RTX in addition to standard of care analgesic therapy (treated, n = 36). Significantly more dogs in the control group (78%) required unblinding and adjustment in analgesic protocol or euthanasia within 6 weeks of randomization, than dogs that were treated with RTX (50%; P < 0.03); and overall, dogs in the control group required unblinding significantly sooner than dogs that had been treated with RTX (P < 0.02). The analgesic effect was documented in these dogs without any evidence of development of deafferentation pain syndrome that can be seen with neurolytic therapies.

Quality of life assessment in domestic dogs: An evidence-based rapid review

Assessment of quality of life (QoL) is an important, increasingly popular outcome measure in veterinary research and practice, particularly in dogs. In humans, QoL is commonly assessed by self-reporting and since this is not possible for animals, it is crucial that instruments designed to measure QoL are tested for reliability and validity. Using a systematic, replicable literature search strategy, the aim of this study was to find published, peer-reviewed instruments for QoL assessment in dogs and to assess the quality of these. CAB Abstracts and PubMed were searched in July 2013 using terms relevant to dogs, wellbeing and QoL. Inclusion and exclusion criteria were applied. When instruments were not published in full, authors were contacted to obtain them. Criteria were applied to assess the quality, validity and reliability of the 52 instruments obtained. Twenty-seven additional instruments used in peer-reviewed publications were not included because they had not been fully described in the publication or were not provided by authors upon request. Most of the instruments reviewed (48/52) were disease-specific rather than generic. Only four publications provided a definition of QoL or wellbeing. Only 11/52 instruments demonstrated evidence of assessing reliability or validity, and the quality of these instruments was variable. Many novel, unvalidated instruments have been generated and applied as clinical outcomes before it was known whether they measured QoL. This rapid review can be used to identify currently available and validated canine QoL instruments, and to assess the validity and quality of new or existing instruments.

Canine osteosarcoma: a naturally occurring disease to inform pediatric oncology

Osteosarcoma (OSA) is the most common form of malignant bone cancer in children and dogs, although the disease occurs in dogs approximately 10 times more frequently than in people. Multidrug chemotherapy and aggressive surgical techniques have improved survival; however, new therapies for OSA are critical, as little improvement in survival times has been achieved in either dogs or people over the past 15 years, even with significant efforts directed at the incorporation of novel therapeutic approaches. Both clinical and molecular evidence suggests that human and canine OSA share many key features, including tumor location, presence of microscopic metastatic disease at diagnosis, development of chemotherapy-resistant metastases, and altered expression/activation of several proteins (e.g. Met, ezrin, phosphatase and tensin homolog, signal transducer and activator of transcription 3), and p53 mutations, among others. Additionally, canine and pediatric OSA exhibit overlapping transcriptional profiles and shared DNA copy number aberrations, supporting the notion that these diseases are similar at the molecular level. This review will discuss the similarities between pediatric and canine OSA with regard to histology, biologic behavior, and molecular genetic alterations that indicate canine OSA is a relevant, spontaneous, large animal model of the pediatric disease and outline how the study of naturally occurring OSA in dogs will offer additional insights into the biology and future treatment of this disease in both children and dogs.