Evaluation of the Effect of a Single Intra-articular Injection of Allogeneic Neonatal Mesenchymal Stromal Cells Compared to Oral Non-Steroidal Anti-inflammatory Treatment on the Postoperative Musculoskeletal Status and Gait of Dogs over a 6-Month Period after Tibial Plateau Leveling Osteotomy: A Pilot Study

Evaluation of stem-cell therapies in companion animal disease models: a concise review (2015-2023)

Companion animals in veterinary medicine develop multiple naturally occurring diseases analogous to human conditions. We previously reported a comprehensive review on the feasibility, safety, and biologic activity of using novel stem cell therapies to treat a variety of inflammatory conditions in dogs and cats (2008-2015) [Hoffman AM, Dow SW. Concise review: stem cell trials using companion animal disease models. Stem Cells. 2016;34(7):1709-1729. https://doi.org/10.1002/stem.2377]. The purpose of this review is to provide an updated summary of current studies in companion animal disease models that have evaluated stem cell therapeutics that are relevant to human disease. Here we have reviewed the literature from 2015 to 2023 for publications on stem cell therapies that have been evaluated in companion animals, including dogs, cats, and horses. The review excluded case reports or studies performed in experimentally induced models of disease, studies involving cancer, or studies in purpose-bred laboratory species such as rodents. We identified 45 manuscripts meeting these criteria, an increase from 19 that were described in the previous review [Hoffman AM, Dow SW. Concise review: stem cell trials using companion animal disease models. Stem Cells. 2016;34(7):1709-1729. https://doi.org/10.1002/stem.2377]. The majority of studies were performed in dogs (n = 28), with additional studies in horses (n = 9) and cats (n = 8). Disease models included those related to musculoskeletal disease (osteoarthritis and tendon/ligament injury), neurologic disease (canine cognitive dysfunction, intervertebral disc disease, spinal cord injury) gingival/dental disease (gingivostomatitis), dermatologic disease (atopic dermatitis), chronic multi-drug resistant infections, ophthalmic disease (keratoconjunctivitis sicca, eosinophilic keratitis, immune-mediated keratitis), cardiopulmonary disease (asthma, degenerative valve disease, dilated cardiomyopathy), gastrointestinal disease (inflammatory bowel disease, chronic enteropathy), and renal disease (chronic kidney disease). The majority of studies reported beneficial responses to stem cell treatment, with the exception of those related to more chronic processes such as spinal cord injury and chronic kidney disease. However, it should also be noted that 22 studies were open-label, baseline-controlled trials and only 12 studies were randomized and controlled, making overall study interpretation difficult. As noted in the previous review, improved regulatory oversight and consistency in manufacturing of stem cell therapies are needed. Enhanced understanding of the temporal course of disease processes using advanced-omics approaches may further inform mechanisms of action and help define appropriate timing of interventions. Future directions of stem-cell-based therapies could include use of stem-cell-derived extracellular vesicles, or cell conditioning approaches to direct cells to specific pathways that are tailored to individual disease processes and stages of illness.

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.

The effect of nonsteroidal anti-inflammatory drug use on soft tissue and bone healing in the knee: a systematic review

Background

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to mitigate pain and inflammation associated with musculoskeletal conditions; however, there is conflicting data on the adverse effects of these drugs on tissue and bone healing. The objective of this study was to investigate the effect of NSAIDs on the healing of knee, soft tissue, and bone.

Methods

A systematic literature search was conducted across PubMed/MEDLINE, Excerpta Medical Database (Embase)/Ovid, and the Cochrane Central Register of Controlled Trials databases. Clinical, animal, and in vitro studies on the effect of NSAIDs on knee healing were included. Risk of bias assessment was performed using the Cochrane bias assessment tool and Methodological Index for Non-Randomized Studies scoring system for included clinical studies, and the Systematic Review Center for Laboratory Animal Experimentation assessment tool for all included animal studies. General study population characteristics, interventions used, NSAIDs utilized, outcome measures, and study results were analyzed using descriptive statistics.

Results

Fifteen articles met the inclusion criteria. Of the 15 studies, there were three clinical, ten animal, and two in vitro studies. In clinical studies, nonselective cyclooxygenase (COX) inhibitors and selective COX-2 inhibitors did not cause a significant increase in failure of anterior cruciate ligament (ACL) reconstructions or meniscal repairs with NSAID administration pre-, peri-, or post-operatively in comparison to placebo or no NSAID administration. Among animal studies assessing COX-2 inhibitor effects on soft tissue, healing was impaired (2/4), delayed but unaffected (1/4), or unaffected (1/4). In animal studies assessing COX-1 inhibitors, ligament healing was either increased (1/4), unaffected (2/4), or impaired (1/4). Meanwhile, administration of non-selective COX inhibitors in animals did not affect soft tissue (3/3) and cartilage (1/1) healing. Two in vitro studies identified a negative outcome on patellar tendon and ACL cell proliferation or viability after non-selective COX inhibition and variable results after selective COX-2 inhibition.

Conclusions

Animal studies on postoperative NSAID use after knee surgery suggest that administration of selective and nonselective COX-2 inhibitors may impair healing of soft tissue, bone and tendon-to-bone; however, further clinical studies are needed to better characterize dose and duration dependent risks of NSAIDs.

Autologous point-of-care stromal vascular fraction transplantation in dogs with advanced osteoarthritis of the knee and hip joints

OBJECTIVE

The aim of the study was to assess lameness in dogs with advanced osteoarthritis of the hip and knee joints after a single autologous point-of-care transplantation of the Stromal Vascular Fraction (SVF) into the affected joint.

MATERIALS AND METHODS

During a minilaparotomy, 10 g of falciform fat was removed from each patient for each joint to be treated. A modern and time-saving procedure (ARC TM System, InGeneron GmbH, Houston, USA) was used for the in-house preparation of the SVF, so that the isolated cells could be applied to the respective joint within 2 h after fat removal. In total, five knee joints of five patients and seven hip joints of four patients were treated.

RESULTS

Improvement in lameness according to owner questionnaires was seen in 3 of 5 patients with knee joint arthritis and 2 of 4 patients with hip joint arthritis. Based on gait analysis, only one dog with gonarthrosis and one dog with coxarthrosis showed improvement up to a maximum of 3 months after surgery.

CONCLUSION

This is the first case series on the treatment of osteoarthrosis of the knee or hip joint using point-of-care transplantation of the SVF. In individual cases, this method may represent a therapeutic approach for the treatment in dogs with advanced cox- or gonarthrosis, although only a short-term effect can be expected, which calls into question the effort and costs involved.

Stem Cell Therapy for Aging Related Diseases and Joint Diseases in Companion Animals

Stem cell therapy is an attractive treatment for diseases in companion animals that cannot be treated by conventional veterinary medicine practices. The unique properties of stem cells, particularly the ability to differentiate into specific cell types, makes them a focal point in regenerative medicine treatments. Stem cell transplantation, especially using mesenchymal stem cells, has been proposed as a means to treat a wide range of injuries and ailments, resulting in tissue regeneration or repair. This review aims to summarize the veterinary use of stem cells for treating age-related and joint diseases, which are common conditions in pets. While additional research is necessary and certain limitations exist, the potential of stem cell therapy for companion animals is immense.

Two Amnion-Derived Mesenchymal Stem-Cells Injections to Osteoarthritic Elbows in Dogs-Pilot Study

The aim of the study was to investigate the potential of cell-based regenerative therapy for elbow joints affected by osteoarthritis. Interest was focused on two intra-articular applications of amnion-derived mesenchymal stem cells (A-MSCs) to a group of different breeds of dogs with elbow osteoarthritis (13 joints). Two injections were performed 14 days apart. We evaluated synovial fluid biomarkers, such as IFN-γ, IL-6, IL-15, IL-10, MCP-1, TNF-α, and GM-CSF, by multiplex fluorescent micro-bead immunoassay in the treated group of elbows (n = 13) (day 0, day 14, and day 28) and in the control group of elbows (n = 9). Kinematic gait analysis determined the joint range of motion (ROM) before and after each A-MSCs application. Kinematic gait analysis was performed on day 0, day 14, and day 28. Kinematic gait analysis pointed out improvement in the average range of motion of elbow joints from day 0 (38.45 ± 5.74°), day 14 (41.7 ± 6.04°), and day 28 (44.78 ± 4.69°) with statistical significance (p < 0.05) in nine elbows. Correlation analyses proved statistical significance (p < 0.05) in associations between ROM (day 0, day 14, and day 28) and IFN-γ, IL-6, IL-15, MCP-1, TNF-α, and GM-CSF concentrations (day 0, day 14, and day 28). IFN-γ, IL-6, IL-15, MCP-1, GM-CSF, and TNF- α showed negative correlation with ROM at day 0, day 14, and day 28, while IL-10 demonstrated positive correlation with ROM. As a consequence of A-MSC application to the elbow joint, we detected a statistically significant (p < 0.05) decrease in concentration levels between day 0 and day 28 for IFN-γ, IL-6, and TNF-α and statistically significant increase for IL-10. Statistical significance (p < 0.05) was detected in TNF-α, IFN-γ, and GM-CSF concentrations between day 14 and the control group as well as at day 28 and the control group. IL-6 concentrations showed statistical significance (p < 0.05) between day 14 and the control group.

Effects of Autologous Microfragmented Adipose Tissue on Healing of Tibial Plateau Levelling Osteotomies in Dogs: A Prospective Clinical Trial

The aim of this study was to evaluate the effects of autologous microfragmented adipose tissue (MFAT) applied after mechanical fragmentation and assess these effects radiographically in bone healing in dogs subjected to tibial plateau levelling osteotomy (TPLO). Twenty dogs with unilateral cranial cruciate ligament disease were enrolled and randomly assigned to the treatment group (MFAT) or the control group (NT). The MFAT group underwent TPLO and autologous MFAT intra-articular administration, while the NT group underwent TPLO alone. Adipose tissue was collected from the thigh region, and MFAT was obtained by mechanical fragmentation at the end of the surgery. The patients were subjected to X-ray examination preoperatively, immediately postoperatively (T0), and at 4 (T1) and 8 (T2) weeks postoperatively. Two radiographic scores that had previously been described for the evaluation of bone healing after TPLO were used. A 12-point scoring system (from 0 = no healing to 12 = complete remodelling) was used at T0, T1, and T2, while a 5-point scoring system (from 0 = no healing to 4 = 76-100% of healing) was used at T1 and T2. The median healing scores were significantly higher at T1 and T2 for the MFAT group compared with the NT group for the 12-point (p < 0.05) and 5-point (p < 0.05) scoring systems. The intra-articular injection of autologous microfragmented adipose tissue can accelerate bone healing after TPLO without complications.

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

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

Case report: Flexor carpi ulnaris tendinopathy in a lure-coursing dog treated with three platelet-rich plasma and platelet lysate injections

In the present case report a 7-year-old male Whippet competing in lure-coursing presented with third-degree recurrent lameness of the right forelimb, pain on palpation of the caudal aspect of the carpus and swelling of the forearm proximally to the accessory carpal bone. Clinical, radiographic, and ultrasonographic evaluation diagnosed a flexor carpi ulnaris (FCU) chronic tendinopathy unresponsive to previously attempted conservative treatments such as oral non-steroidal anti-inflammatory drugs (NSAIDs) administration along with padded palmar splint application and rest. The dog was subjected to one injection of autologous platelet-rich plasma (PRP) obtained using a double centrifugation tube method, followed by two platelet lysate (PL) injections. Treatment was administered at three-week intervals. The healing process was assessed through clinical and ultrasonographic imaging (US) on the day of the first injection (T0), and at week three (T1), six (T2), twelve (T3), fifty-two (T4), and one-hundred-and-four (T5). Fiber alignment score (FAS) and echogenicity score (ES) were developed by modifying a previously published US assessment scale. At T1, ES, and FAS improvement was detected, and at T2, further improvements in ES and FAS were observed. Ultrasonographic results were clinically consistent with the improvement in lameness: lameness grade 3/4 was detected at T0 and grade 2/4 at T1. A lameness grade of 1/4 was detected at T2, and grade 0/4 was observed at T3, T4, and T5. Moreover, at T5, the dog returned to competition, and no history of re-injury was reported. Our results suggest that the treatment of FCU tendinopathy in lure-coursing dogs with a combination of consecutive injections of autologous PRP and PL could be feasible. Additionally, no adverse reactions were observed.

The Pivotal Role of Stem Cells in Veterinary Regenerative Medicine and Tissue Engineering

The introduction of new regenerative therapeutic modalities in the veterinary practice has recently picked up a lot of interest. Stem cells are undifferentiated cells with a high capacity to self-renew and develop into tissue cells with specific roles. Hence, they are an effective therapeutic option to ameliorate the ability of the body to repair and engineer damaged tissues. Currently, based on their facile isolation and culture procedures and the absence of ethical concerns with their use, mesenchymal stem cells (MSCs) are the most promising stem cell type for therapeutic applications. They are becoming more and more well-known in veterinary medicine because of their exceptional immunomodulatory capabilities. However, their implementation on the clinical scale is still challenging. These limitations to their use in diverse affections in different animals drive the advancement of these therapies. In the present article, we discuss the ability of MSCs as a potent therapeutic modality for the engineering of different animals' tissues including the heart, skin, digestive system (mouth, teeth, gastrointestinal tract, and liver), musculoskeletal system (tendons, ligaments, joints, muscles, and nerves), kidneys, respiratory system, and eyes based on the existing knowledge. Moreover, we highlighted the promises of the implementation of MSCs in clinical use in veterinary practice.

Manufacturing Mesenchymal Stromal Cells for the Treatment of Osteoarthritis in Canine Patients: Challenges and Recommendations

The recent interest in advanced biologic therapies in veterinary medicine has opened up opportunities for new treatment modalities with considerable clinical potential. Studies with mesenchymal stromal cells (MSCs) from animal species have focused on in vitro characterization (mostly following protocols developed for human application), experimental testing in controlled studies and clinical use in veterinary patients. The ability of MSCs to interact with the inflammatory environment through immunomodulatory and paracrine mechanisms makes them a good candidate for treatment of inflammatory musculoskeletal conditions in canine species. Analysis of existing data shows promising results in the treatment of canine hip dysplasia, osteoarthritis and rupture of the cranial cruciate ligament in both sport and companion animals. Despite the absence of clear regulatory frameworks for veterinary advanced therapy medicinal products, there has been an increase in the number of commercial cell-based products that are available for clinical applications, and currently the commercial use of veterinary MSC products has outpaced basic research on characterization of the cell product. In the absence of quality standards for MSCs for use in canine patients, their safety, clinical efficacy and production standards are uncertain, leading to a risk of poor product consistency. To deliver high-quality MSC products for veterinary use in the future, there are critical issues that need to be addressed. By translating standards and strategies applied in human MSC manufacturing to products for veterinary use, in a collaborative effort between stem cell scientists and veterinary researchers and surgeons, we hope to facilitate the development of quality standards. We point out critical issues that need to be addressed, including a much higher level of attention to cell characterization, manufacturing standards and release criteria. We provide a set of recommendations that will contribute to the standardization of cell manufacturing methods and better quality assurance.

Current Status on Canine Foetal Fluid and Adnexa Derived Mesenchymal Stem Cells

Effective standards of care treatment guidelines have been developed for many canine diseases. However, a subpopulation of patients is partially or completely refractory to these protocols, so their owners seek novel therapies such as treatments with MSCs. Although in dogs, as with human medicine, the most studied MSCs sources have been bone marrow and adipose tissue, in recent years, many researchers have drawn attention towards alternative sources, such as foetal adnexa and fluid, since they possess many advantages over bone marrow and adipose tissue. Foetal adnexa and fluid could be considered as discarded material; therefore, sampling is non-invasive, inexpensive and free from ethical considerations. Furthermore, MSCs derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate and seem to present immune-modulatory properties that make them a good candidate for allo- and xenotransplantation. The aim of the present review is to offer an update on the state of the art on canine MSCs derived from foetal adnexa and fluid focusing on the findings in their clinical setting.

Clinical application of mesenchymal stem cells therapy in musculoskeletal injuries in dogs-a review of the scientific literature

Mesenchymal stem cells (MSCs) are multipotent, which is defined by their ability to self-renew while maintaining the capacity to differentiate into a certain number of cells, presumably from their own germinal layer. MSCs therapy is based on their anti-inflammatory, immunomodulatory (immunosuppressive), and regenerative potential. This review aims to provide a clinical overview of the MSCs potential as a therapeutic option for orthopedic diseases in dogs. A total of 25 clinical studies published in the scientific literature in the last 15 years on various diseases will be presented: semitendinosus myopathy, supraspinatus tendinopathy, cruciate ligament rupture, bone fractures and defects, and also osteoarthritis (OA). All articles involved in this study include only diseases that have naturally occurred in canine patients. MSCs therapy in the veterinary orthopedic field has great potential, especially for OA. All studies presented promising results. However, MSCs bone healing capacity did not reveal such favorable outcomes in the long term. Besides, most of these clinical studies did not include immunohistochemistry, immunofluorescence, and histopathology to confirm that MSCs have differentiated and incorporated into the injured tissues. This review summarizes the current knowledge of canine MSCs biology, immunology, and clinical application in canine orthopedic diseases. Despite the positive results in its use, there is still a lack of defined protocols, heterogeneous samples, and concomitant medications used with MSCs therapy compromising therapeutic effects. Further studies are needed in the hope of overcoming its limitation in upcoming trials.

Comparison of Canine and Feline Adipose-Derived Mesenchymal Stem Cells/Medicinal Signaling Cells With Regard to Cell Surface Marker Expression, Viability, Proliferation, and Differentiation Potential

Remarkable immunomodulatory abilities of mesenchymal stem cells, also called multipotent mesenchymal stromal cells or medicinal signaling cells (MSCs), have entailed significant advances in veterinary regenerative medicine in recent years. Despite positive outcomes from MSC therapies in various diseases in dogs and cats, differences in MSC characteristics between small animal veterinary patients are not well-known. We performed a comparative study of cells' surface marker expression, viability, proliferation, and differentiation capacity of adipose-derived MSCs (ADMSCs) from dogs and domestic cats. The same growth media and methods were used to isolate, characterize, and culture canine and feline ADMSCs. Adipose tissue was collected from 11 dogs and 8 cats of both sexes. The expression of surface markers CD44, CD90, and CD34 was detected by flow cytometry. Viability at passage 3 was measured with the hemocytometer and compared to the viability measured by flow cytometry after 1 day of handling. The proliferation potential of MSCs was measured by calculating cell doubling and cell doubling time from second to eighth passage. Differentiation potential was determined at early and late passages by inducing cells toward adipogenic, osteogenic, and chondrogenic differentiation using commercial media. Our study shows that the percentage of CD44⁺CD90⁺ and CD34^−/− cells is higher in cells from dogs than in cells from cats. The viability of cells measured by two different methods at passage 3 differed between the species, and finally, canine ADMSCs possess greater proliferation and differentiation potential in comparison to the feline ADMSCs.

Stem Cells in Veterinary Medicine-Current State and Treatment Options

Regenerative medicine is a branch of medicine that develops methods to grow, repair, or replace damaged or diseased cells, organs or tissues. It has gained significant momentum in recent years. Stem cells are undifferentiated cells with the capability to self—renew and differentiate into tissue cells with specialized functions. Stem cell therapies are therefore used to overcome the body's inability to regenerate damaged tissues and metabolic processes after acute or chronic insult. The concept of stem cell therapy was first introduced in 1991 by Caplan, who proposed that massive differentiation of cells into the desired tissue could be achieved by isolation, cultivation, and expansion of stem cells in in vitro conditions. Among different stem cell types, mesenchymal stem cells (MSC) currently seem to be the most suitable for therapeutic purposes, based on their simple isolation and culturing techniques, and lack of ethical issues regarding their usage. Because of their remarkable immunomodulatory abilities, MSCs are increasingly gaining recognition in veterinary medicine. Developments are primarily driven by the limitations of current treatment options for various medical problems in different animal species. MSCs represent a possible therapeutic option for many animal diseases, such as orthopedic, orodental and digestive tract diseases, liver, renal, cardiac, respiratory, neuromuscular, dermal, olfactory, and reproductive system diseases. Although we are progressively gaining an understanding of MSC behavior and their mechanisms of action, some of the issues considering their use for therapy are yet to be resolved. The aim of this review is first to summarize the current knowledge and stress out major issues in stem cell based therapies in veterinary medicine and, secondly, to present results of clinical usage of stem cells in veterinary patients.

A Protocol for the Isolation, Culture, and Cryopreservation of Umbilical Cord-Derived Canine Mesenchymal Stromal Cells: Role of Cell Attachment in Long-Term Maintenance

Mesenchymal stromal cells (MSCs) hold great promise in the field of regenerative medicine due to their ability to create a variable localized anti-inflammatory effect in injuries such as Crohn's disease and osteoarthritis or by incorporation in tissue engineered constructs. Currently, the MSC literature uses rodents for preclinical disease models. There is growing interest in using naturally occurring disease in large animals for modeling human disease. By review of the canine MSCs literature, it appears that canine MSCs can be difficult to maintain in culture for extended passages and this greatly varies between tissue sources, compared with human and rodent MSCs, and limited lifespan is an obstacle for preclinical investigation and therapeutic use. Research using canine MSCs has been focused on cells derived from bone marrow or adipose tissue, and the differences in manufacturing MSCs between laboratories are problematic due to lack of standardization. To address these issues, here, a stepwise process was used to optimize canine MSCs isolation, expansion, and cryopreservation utilizing canine umbilical cord-derived MSCs. The culture protocol utilizes coating of tissue culture surfaces that increases cellular adherence, increases colony-forming units-fibroblast efficiency, and decreases population doubling times. Canine MSCs isolated with our protocol could be maintained longer than published canine MSCs methods before senescing. Our improved cryopreservation protocols produce on average >90% viable MSCs at thaw. These methods enable master-bank and working-bank scenarios for allogeneic MSC testing in naturally occurring disease in dogs.

Comparison of efficacy and safety of single versus repeated intra-articular injection of allogeneic neonatal mesenchymal stem cells for treatment of osteoarthritis of the metacarpophalangeal/metatarsophalangeal joint in horses: A clinical pilot study

The purpose of this prospective study was to evaluate the effects of single and repeated intra-articular administration of allogeneic, umbilical cord-derived, neonatal mesenchymal stem cells (MSC) in horses with lameness due to osteoarthritis (OA) of a metacarpophalangeal joint (MPJ).

Twenty-eight horses were included. Horses were divided into two groups. Horses in group MSC1 received an MSC injection at M0 and a placebo injection at M1 (1 month after M0). Horses in group MSC2 received MSC injections at M0 and at M1. Joint injections were performed with a blinded syringe. Clinical assessment was performed by the treating veterinarian at M1, M2 and M6 (2 and 6 months after M0), including lameness evaluation, palpation and flexion of the joint. Radiographic examination of the treated joints was performed at inclusion and repeated at M6. Radiographs were anonymized and assessed by 2 ECVDI LA associate members. Short term safety assessment was performed by owner survey. A 2-month rehabilitation program was recommended to veterinarians. There was a significant improvement of the total clinical score for horses in both groups. There was no significant difference in the total clinical score between groups MSC1 and MSC2 at any time point in the study. There was no significant difference in the total radiographic OA score, osteophyte score, joint space width score and subchondral bone score between inclusion and M6. Owner-detected adverse effects to MSC injection were recorded in 18% of the horses. Lameness caused by OA improved significantly over the 6-month duration of the study after treatment with allogeneic neonatal umbilical cord-derived MSCs combined with 8 weeks rest and rehabilitation. There is no apparent clinical benefit of repeated intra-articular administration of MSCs at a 1-month interval in horses with MPJ OA when compared to the effect of a single injection.

Mesenchymal stem cell basic research and applications in dog medicine

The stem cells, owing to their special characteristics like self-renewal, multiplication, homing, immunomodulation, anti-inflammatory, and dedifferentiation are considered to carry an "all-in-one-solution" for diverse clinical problems. However, the limited understanding of cellular physiology currently limits their definitive therapeutic use. Among various stem cell types, currently mesenchymal stem cells are extensively studied for dog clinical applications owing to their readily available sources, easy harvesting, and ability to differentiate both into mesodermal, as well as extramesodermal tissues. The isolated, culture expanded, and characterized cells have been applied both at preclinical as well as clinical settings in dogs with variable but mostly positive results. The results, though positive, are currently inconclusive and demands further intensive research on the properties and their dependence on the applications. Further, numerous clinical conditions of dog resemble to that of human counterparts and thus, if proved rewarding in the former may act as basis of therapy for the latter. The current review throws some light on dog mesenchymal stem cell properties and their potential therapeutic applications.

Long-Term Safety and Efficacy of Single or Repeated Intra-Articular Injection of Allogeneic Neonatal Mesenchymal Stromal Cells for Managing Pain and Lameness in Moderate to Severe Canine Osteoarthritis Without Anti-inflammatory Pharmacological Support: Pilot Clinical Study

Objective: To explore the long-term safety and efficacy of canine allogeneic mesenchymal stromal cells (MSC) administered intra-articularly as single or repeated injections in appendicular joints of dogs affected by moderate to severe refractory osteoarthritis.

Study Design: 22 pet dogs were recruited into a non-randomized, open and monocentric study initially administering one cellular injection. A second injection was offered after 6 months to owners if the first injection did not produce expected results.

Materials and Methods: Anti-inflammatory treatment (if prescribed) was discontinued at last one week before the onset of treatment. Each injection consisted of at least 10 million viable neonatal allogeneic mesenchymal stromal cells obtained from fetal adnexa. Medical data was collected from veterinary clinical evaluations of joints up to 6 months post-injection and owner's assessment of their dog's mobility and well-being followed for a further 2 years when possible.

Results: Mild, immediate self-limiting inflammatory joint reactions were observed in 5/22 joints after the first injection, and in almost all dogs having a subsequent injection. No other MSC-related adverse medical events were reported, neither during the 6 months follow up visits, nor during the long-term (2-years) safety follow up. Veterinary clinical evaluation showed a significant and durable clinical improvement (up to 6 months) following MSC administration. Eight dogs (11 joints) were re-injected 6 months apart, sustaining clinical benefits up to 1 year. Owner's global satisfaction reached 75% at 2 years post-treatment

Conclusion: Our data suggest that a single or repeated intra-articular administration of neonatal MSC in dogs with moderate to severe OA is a safe procedure and confer clinical benefits over a 24-month period. When humoral response against MSC is investigated by flow cytometry, a positive mild and transient signal was detected in only one dog from the studied cohort, this dog having had a positive clinical outcome.