Autologous peripheral blood-derived orthobiologics: Different types and their effectiveness in managing knee osteoarthritis

Knees are the most commonly impacted weight-bearing joints in osteoarthritis (OA), affecting millions of people worldwide. With increasing life spans and obesity rates, the incidence of knee OA will further increase, leading to a significant increase in the economic burden. Conventional treatment modalities utilized to manage knee OA have limitations. Over the last decade, the role of various autologous peripheral blood-derived orthobiologics (APBOs) for the treatment of knee OA has been extensively investigated. This editorial provided an overview and focused on defining and shedding light on the current state of evidence based on the most recent published clinical studies concerning the use of APBO for the management of knee OA. While numerous studies have demonstrated promising results for these preparations, a notable gap exists in the comparative analysis of these diverse formulations. This absence of head-to-head studies poses a considerable challenge for physicians/surgeons in determining the optimal preparation for managing knee OA and achieving sustained long-term results. Thus, more adequately powered, multicenter, prospective, double-blind, randomized controlled trials with longer follow-ups are needed to establish the long-term efficacy and to aid physicians/surgeons in determining the optimal APBO for the management of knee OA.

Evaluation of the efficacy of autologous conditioned serum versus dextrose prolotherapy in internal derangement of the TMJ - A pilot study

It was the aim of the study to compare the effectiveness of autologous conditioned serum (ACS) and dextrose prolotherapy (DP) solutions, in treating patients with TMJ internal derangement (ID). 24 participants with TMJ ID (Wilkes II-V) were recruited and randomized into study and control groups, with 12 patients each, treated with IA injection of ACS and DP, respectively. Pain, mouth opening, joint sounds, and jaw deviation were evaluated, with patients reviewed at 2 weeks, 1 month, and 2 months intervals. Based on the nature of the variables, appropriate descriptive statistics and statistical tests were applied. The pain score was zero in the study group after 2 months of treatment, which was statistically significant (p = 0.006). Deviation was also significantly reduced (p < 0.001) and mouth opening significantly improved (p = 0.004) in the ACS-treated patients. ACS demonstrated superiority over DP in the management of TMJ dysfunction. Therefore, ACS can be considered an ideal, minimally invasive treatment option for TMJ ID. Clinical trial registry number: (CTRI/2021/10/037043).

Interactions Between Biologic Therapies and Other Treatment Modalities

Biologic therapies are becoming increasingly utilized by veterinarians. The literature regarding the interaction of biologic therapies with other therapeutics is still in its infancy. Initial studies have examined the effects of exercise, stress, various pharmaceutical interventions, extracorporeal shockwave, therapeutic laser, and hyperbaric oxygen on biologic therapies. Continued research is imperative as owners and veterinarians increasingly choose a multimodal approach to injury and illness. Further, understanding the effects of concurrently administered treatments and pharmaceuticals as well as the health status of the horse is imperative to providing the optimal therapeutic outcome.

Introduction to Equine Biologic and Regenerative Therapies

Regenerative medicine is defined as the process of replacing or regenerating cells, tissues, or organs to restore or establish normal function. The use of regenerative medicine in equine practice to treat injured musculoskeletal tissues with limited capacity for intrinsic healing is growing. This article provides the practitioner with a brief and basic overview of the regenerative products currently used in equine practice.

Efficacy of conditioned autologous serum therapy (Orthokine®) on the dorsal root ganglion in patients with chronic radiculalgia: study protocol for a prospective randomized placebo-controlled double-blind clinical trial (RADISAC trial)

BACKGROUND

Pulsed radiofrequency (PRF) treatment on the dorsal root ganglion (DRG) has been proposed as a good option for the treatment of persistent radicular pain based on its effect of neuromodulation on neuropathic pain. Autologous conditioned serum (ACS) therapy is a conservative treatment based on the patient's own blood. The aim of this manuscript is to develop a study protocol using ACS on the DRG as a target for its molecular modulation.

METHODS

We plan to conduct a randomized controlled study to compare the efficacy of PRF therapy plus ACS versus PRF therapy plus physiological saline 0.9% (PhS) on the DRG to reduce neuropathic pain in patients with persistent lower limb radiculalgia (LLR) and to contribute to the functional improvement and quality of life of these patients. Study participants will include patients who meet study the inclusion/exclusion criteria. Eligible patients will be randomized in a 1:1 ratio to one of treatment with PRF plus ACS (experimental group) or PRF plus PhS (placebo group). The study group will consist of 70 patients (35 per group) who have experienced radicular pain symptoms for ≥ 6 months' duration who have failed to respond to any therapy. Both groups will receive PRF on the DRG treatment before the injection of the sample (control or placebo). Patient assessments will occur at baseline, 1 month, 3 months, 6 months, and 12 months after therapy. The primary efficacy outcome measure is Numeric Pain Rating Scale (NPRS) responders from baseline to 12 months of follow-up using validated minimal important change (MIC) thresholds. A reduction of ≥ 2 points in NPRS is considered a clinically significant pain relief. The secondary efficacy outcome measure is the proportion of Oswestry Low Back Pain Disability Scale (ODS) responders from baseline to 12 months of follow-up in the experimental group (PRF plus ACS) versus the placebo group (PRF plus PhS). ODS responders are defined as those patients achieving the validated MIC of ≥ 10-point improvement in ODS from baseline to 12 months of follow-up as a clinically significant efficacy threshold.

DISCUSSION

This prospective, double-blind, randomized placebo-controlled study will provide level I evidence of the safety and effectiveness of ACS on neuropathic symptoms in LLR patients. TRIAL REGISTRATION {2A}{2B}: EUDRACT number: 2021-005124-38. Validation date: 13 November 2021. Protocol version {3}: This manuscript presents the 2nd protocol version.

Cytokine enrichment in equine conditioned serum is not reliant on incubation in specialized containers

Autologous conditioned serum (ACS), i.e serum enriched with anti-inflammatory cytokines and growth factors, is a popular orthobiologic therapy used in equine practice. Costly specialized tubes containing glass beads are commonly used for ACS production. The objective of this in vitro study was to compare cytokine and growth factor levels in equine serum after incubation in three different tubes: commercial plastic ACS tubes (COMM); sterile 50 ml plastic centrifugation tubes (CEN); and 10 ml plastic vacutainer tubes (VAC). Blood from 15 healthy horses was incubated in the different tubes at 37°C for 22-24 h. The concentration of IL-1β, IL-1Ra, IL-10, IGF-1 and PDGF-BB was determined by ELISA and compared between tubes. There was no difference in concentration of IL-1Ra and IGF-1 between CEN and COMM. PDGF-BB was higher in CEN vs. COMM (P < 0.0001). IL-1Ra and PDGF-BB was higher (P < 0.005 and P = 0.02, respectively) whereas IGF-1 was lower in VAC (P < 0.003) vs. the other tubes. The centrifuge tube performed similarly to the commercial ACS tube in cytokine and growth factor enrichment and has the potential to dramatically reduce the cost of ACS treatment. Cytokine enrichment of equine serum does not require blood incubation in specialized ACS containers.

The therapeutic effects of autologous conditioned serum on knee osteoarthritis: an animal model

Objective

As a progressive chronic condition, osteoarthritis (OA) causes substantial pain and impairment. Secrete proinflammatory cytokines are essential mediators involved in the pathophysiology of OA. In this regard, the clinical effectiveness of autologous conditioned serum (ASC) has been shown through its injection into OA tissues. This study aimed to assess the effectiveness and concentration level of ACS components produced by Nano-carbon glass beads.

Intravenous whole blood was obtained from each New Zealand male rabbit by 10-ml syringes, comprising 33 medical-grade Nano carbon-coated glass beads. Serum retrieving was performed after 6–8 h incubation (37 C, 5% Co₂), and then centrifuged. The ACS was then injected into OA rabbits to assess its function.

Results

Glass beads-prepared ACS coated with Nano-carbon, induced a huge amount of cytokines and growth factors production. The concentration level of anti-inflammatory cytokines and proinflammatory cytokines was improved throughout Nano-carbon coated glass beads stimulation. ACS also shortened the recovery time and improved the function and mobility of OA rabbits.

We showed that ACS improved the function and mobility of OA rabbits, as well as shortened the recovery time. It is suggested that further studies evaluate this effectiveness.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06166-1.

Autologous conditioned serum (Orthokine) injection for treatment of classical trigeminal neuralgia: results of a single-center case series

BACKGROUND

Despite some advances, treatment of trigeminal neuralgia remains a significant challenge. This study determines the efficacy and safety of autologous conditioned serum (Orthokine) injection into the foramen oval to treat refractory trigeminal neuralgia.

CASE PRESENTATION

This is a consecutive case series from the Pain and Palliative Care Department of Imam Reza University Hospital, Tabriz, Iran. Eleven Iranian patients, eligible according to the inclusion and exclusion criteria, aged 45.64 ± 11.58 years (Four male and seven female, all Iranian) with established classical trigeminal neuralgia were injected with Orthokine (2 mL per injection) once a week for three consecutive weeks (total of four injections). Numeric rating scale scores for facial pain intensity and also carbamazepine daily dose were confirmed at pretreatment (T0) and at week 1 (T1), week 2 (T2), week 3 (T3), week 4 (T4), and month 2 (T5) posttreatment. Pain intensity was significantly reduced in the first 3 weeks of follow-up in comparison with baseline (T0 to T3) (8.18 ± 1.99 to 2.82 ± 2.13, p < 0.001), an effect that was retained at week 4 (T4) and month 2 (T5) follow-ups (2.82 ± 2.13 to 3.36 ± 2.69, p = 0.886). Carbamazepine consumption was significantly reduced in the first 3 weeks of follow-up in comparison with baseline (T0 to T3) (636.36 ± 307.48 to 200.00 ± 296.64, p = 0.003), an effect that was retained at week 4 and month 2 follow-ups (200.00 ± 296.64 to 200.00 ± 282.84, p = 0.802). There were no serious adverse events in participants.

CONCLUSION

Orthokine injection led to consistent pain relief and reduced carbamazepine dosage in patients with trigeminal neuralgia, with acceptable safety.

Evaluation of Treatment With Respiratory Gene Technology and Serum in a Group of Standard Bred Racehorses With Cytological Evidence of Mild Equine Asthma

Alternative treatment options to glucocorticoids for equine asthma is desirable due to withdrawal time. The objective was to evaluate if serum and Respiratory Gene Technology (RGT), a commercial kit to produce autologous conditioned serum, was effective in reducing bronchoalveolar lavage (BAL) neutrophils and mast cells in racehorses with cytological evidence of mild equine asthma . Thirty-six Standardbred trotters in active training were enrolled in this randomized clinical trial; a healthy control group (n=11), a RGT group (n=12) and a serum group (n=13). Endoscopy including tracheal wash (TW) and BAL was performed before (T0), after a 6-week treatment period including 12 intramuscular injections of RGT or serum (T6) and as a follow-up 10 weeks after treatment (T16). A significant decrease in BAL neutrophils for the RGT group was found between T0 and T6 (P = .002, d=-1.51, CI: -2.43;-0.59) and for the serum group between T0-T6 (P = .002, d=-1.36, CI: -2.26;-0.46). Further, a significant decrease in BAL mast cells between T0-T6 for the both the RGT group (P = .019, d=-1.23, CI: -1.22;-0.34) and the serum group (P= .004, d=-0.81, CI: -1.65;0.04), and further between T0-T16 (RGT P= .011, d=-1.55, CI: -2.62;-0.48; serum P= .044, d=-0.65, CI: -1.68;-0.37). No significant difference in TW cytology was found for any of the time-points. Pro- and anti-inflammatory cytokines were regulated according to treatment. The control group showed no cytological differences between any time-point. Study results showed that intramuscular treatment with both RGT and serum was effective associated with reduction of BAL neutrophils and mast cells in horses with cytological evidence of mild equine asthma. Further large-scale studies are necessary.

Autologous conditioned serum: clinical and functional results using a novel disease modifying agent for the management of knee osteoarthritis

Objective: The purpose of this study was to investigate the potential ability of autologous conditioned serum (ACS) to decrease pain and improve joint functionality in patients affected by knee osteoarthritis (OA). Methods: Fifteen patients with clinical and radiological signs of OA of the knee were recruited for this study. Each patient received 4 injections of ACS (Orthokine; orthogen, Dusseldorf, Germany) at the site of OA once per week for 4 weeks. Clinical and functional evaluation was performed using the VAS scale for pain, WOMAC scale and KSS functional and clinical scores before the first injection, at one week, at two weeks, at three weeks, at one month and at six months. Statistical analysis was done with the Wilcoxon Signed-Rank Test. Results: Our results show an improvement of all the evaluation scales at 6 months follow-up. Particularly, VAS scales among all patients decreased by 35.8% (p = .00148), KSS functional scores improved by 38.2% (p = .00148), KSS clinical scores improved by 28.9% (p = .00236) and WOMAC scores were reduced by 19.8% (p = .00188). Few adverse effects were observed in our sample. The most common complaint was pain and swelling in the subsequent days after performing the intra-articular injection. Only one patient reported rigidity following the injection of the ACS. Conclusion: Our results, in conjunction with preexisting studies in the medical literature regarding ACS, demonstrate the viability of this therapy for the treatment of knee OA, showing positive influence on pain and joint function without significant adverse effects.

Injection with autologous conditioned serum has better clinical results than eccentric training for chronic Achilles tendinopathy

PURPOSE

Chronic Achilles tendinopathy is one of the most common causes of malfunction and pain, which can lead to a significant reduction of the quality of life. The hypothesis of this study argues that autologous conditioned serum (i.e. Orthokine) injections in chronic midportion Achilles tendinopathy have a better outcome than eccentric training.

METHODS

This study investigates, retrospectively, the effects of peritendinous autologous conditioned serum injections as compared to standard eccentric training in 50 patients with chronic Achilles tendinopathy between 2012 and 2015. Before injection or eccentric training and 6 weeks, 12 weeks and 6 months thereafter, the patients were assessed by means of the VISA-A-G score (Victorian Institute of Sport Assessment-Achilles questionnaire-German). An MRI was also performed before and 6 months after injection and eccentric training.

RESULTS

Both patient groups had statistically significant better VISA-A-G scores after injection or eccentric training compared to the baseline before injection (90 vs 40, respectively, P < 0.001) or eccentric training (81 vs 47, respectively, P < 0.001). Comparing the baseline corrected VISA-A-G scores, patients in the autologous-conditioned-serum-group had significantly higher changes in VISA-A-G scores than the eccentric-training-group after 12 weeks (40 vs 36, P = 0.018) and 6 months (50 vs 34, P = 0.034). Both patient groups had statistically significant (P < 0.001) reduction of tendon thickness (autologous conditioned serum: 0.32; eccentric training: 0.24) and length of bursa (autologous conditioned serum: 0.24; eccentric training: 0.21) as well as significant (P < 0.001) improvement of tendon quality in MRI (autologous conditioned serum: 14 vs 1; eccentric training: 14 vs 2). There were no statistical differences in MRI-findings between the two groups.

CONCLUSION

Both therapies led to improvement of MRI-findings, including reduction of tendon thickness and tendon quality. Autologous-conditioned-serum-injections show greater clinical long-term benefit as compared to eccentric training and, therefore, offers a good alternative to eccentric training.

LEVEL OF EVIDENCE

Therapeutic studies, Level III.

Autologous conditioned serum (ACS) for intra-articular treatment in Osteoarthritis: Retrospective report of 28 cases

INTRODUCTION

Autologous conditioned serum (ACS) is a novel blood product developed for intra-articular injection as a novel therapy for Osteoarthritis (OA). This study is a retrospective evaluation of 28 cases (25 Knee-OA and 3 hip-OA) treated with ACS between November 2013 and February 2016.

MATERIALS AND METHODS

ACS was prepared according to standards in an accredited Cell Manipulation Lab, and applied by an expert clinician (2 ml injection once weekly over 4 weeks). At any injection visit (Timepoints 1-4), and after a follow-up of 1 (Timepoint 5) and 6 months (Timepoint 6), patients were asked to describe the intensity of their pain with the VAS (visual analog scale) psychometric scale, and the objective parameter ROM (Range Of Motion) was recorded in case of injection in the knee.

RESULTS

Pain (VAS) reduced in all cases since the first injection up to Timepoint 5. A significant improvement was observed in VAS between Timepoint 1 and 6 (primary objective), with a median VAS decrease of 60 mm (range 20-100, p < 0.01). A significant difference was also recorded in ROM between Timepoint 1 and 6 (secondary objective), with a median increase of 25° (range 5-40, p < 0.01). Ten out of 14 patients (71%) who were undergoing a chronic therapy to relieve pain were able to interrupt it. No serious adverse events were recorded.

CONCLUSIONS

Treatment with ACS produced a rapid decline in pain, accompanied by a large improvement in ROM. These results suggest that ACS is a valid option for the treatment of OA.

Investigation of the biomechanical and histopathological effects of autologous conditioned serum on healing of Achilles tendon

Objective

The aim of this study to evaluate the effects of autologous conditioned serum (ACS) on the healing of transected rat Achilles tendons via the assessment of biomechanical and histological parameters.

Methods

The study was conducted on 45 male Sprague–Dawley rats. Five rats were used as donors for ACS preparation. Animals were randomly assigned to the experimental or control group. In both groups, the Achilles tendon was cut transversally and then sutured. In the placebo control and ACS-treated groups, saline or ACS, respectively, was injected into the repair zone three times after surgery. Ten rats from each group (ACS group, n = 20; control group, n = 20) were euthanized at days 15 and 30 after surgery for histopathological (n = 5) and biomechanical (n = 5) testing. The histopathological findings were interpreted using the Bonar and Movin scales. Tendon remodelling was evaluated via the immunohistochemical staining of collagen type 3. Biomechanical effects were assessed by tensile testing.

Results

The Bonar and Movin scale scores were significantly better in the ACS-treated group on both day 15 (p = 0.003 and p = 0.003, respectively) and day 30 (p = 0.005 and p = 0.004, respectively). The immunohistochemical density of collagen type 3 was significantly lower in the ACS-treated group on day 30 (p = 0.018). The type 1/3 collagen ratios of the groups were similar on days 15 and 30, as determined by Sirius Red staining (p = 0.910 and p = 0.133, respectively). In the biomechanical assessment results, the ACS-treated group's maximum load to failure values were significantly higher on day 15 (p = 0.049).

Conclusion

Injection of ACS had a positive effect on the histopathological healing of rat Achilles tendons on days 15 and 30 and on biomechanical healing on day 15. ACS treatment contributed to lowering the collagen type 3 density by day 30. According to our study, ACS may be favourable for the treatment of human Achilles tendon injuries and tendinopathies.

A short report on the effect of decreased incubation time on the architectural profile of autologous conditioned serum (ACS)

If present in high enough concentrations, IL-1-Ra has the potential to inhibit Interleukin-1, the chief offender that promotes the pro-inflammatory cascade causing pain, swelling and joint dysfunction associated with osteoarthritis (OA). IL-1-Ra and growth factor levels were quantified from whole blood in this retrospective chart review investigation (n=20) using Zero and 15min incubation times respectively. The hypothesis that this process can significantly (p<0.0001) increase levels of IL-1-Ra was confirmed. Mean Arthrokinex™ induced IL-1-Ra levels reached a concentration of 13,288pg/mL and 12,809pg/mL compared to 518pg/mL at baseline, representing a 26-fold increase. Post conditioning levels of pro-inflammatories IL-1β, IL-6 and TNF α were not changed to any significant degree. The Arthrokinex™ blood conditioning process induces adequate levels of IL-1-Ra to alter the IL-1-Ra: IL-1β ratio and mitigate the inflammatory cascade, while increasing growth factors PDGF and TGF respectively.

A new treatment for knee osteoarthritis: Clinical evidence for the efficacy of Arthrokinex™ autologous conditioned serum

OBJECTIVE

The desired therapeutic effect of Arthrokinex™ autologous conditioned serum (ACS) is facilitated by the ability of IL-1-Ra to limit the destructive inflammatory intra-articular (IA) actions of IL-1β. Previous studies have proven the capacity of Arthrokinex™ (ACS) to induce the anti-inflammatory cytokine, IL-1-Ra. The primary purpose of this retrospective study was to investigate the effect of Arthrokinex™ (ACS) to reduce pain, improve joint function and enhance quality of life in patients with knee osteoarthritis.

METHODS

Venous blood from 100 patients with symptomatic knee osteoarthritis (KOA) was conditioned and injected into the affected joint in this treatment protocol. Each patient received a total of six ultrasound-guided IA injections at day 0, 7, 14, 90, 180, and 270 and followed for up to one year. Treatment outcome measures were assessed by three different patient-administered surveys at each visit. Using the Visual Analog Pain Scale (VAS), participants were asked to classify pain in the previous 24 h. The Extra Short Musculoskeletal Functional Assessment (XSMFA-D) survey is a series of 16 questions designed to determine the functionality of the OA-affected joint. Finally, the patient completed a patient global impression of change (PGIC) survey to assess their individual level of satisfaction with the treatment regimen.

RESULTS

Compared to baseline, a total of 84% of patients reported better pain control at 6 months with 91% reporting improvement at 12 months. A robust and statistically significant improvement in each XSMFA-D subscale was observed in KOA patients over 12 months. The overall reduction of pain and enhanced joint function was observed within 1 week and sustained 3, 6 and even 12 months after the initial injection. In addition to symptomatic control of OA, 92% of patients reported satisfaction with the treatment regimen 12 months after the initial injection.

CONCLUSION

Given the favorable safety profile, reduction in pain and enhanced quality of life experienced by patients enrolled in this joint health program, Arthrokinex™ (ACS) has the potential to offer an alternative, chondroprotective, natural, molecular approach to treating pain and functionality in patients with mild, moderate or severe knee osteoarthritis.

Autologous Conditioned Serum as a Novel Alternative Option in the Treatment of Unilateral Lumbar Radiculopathy: A Prospective Study

Study Design

The study was conducted on patients who received autologous conditioned serum (ACS) as a line of treatment at the Orthopedics outpatient department of Post Graduate Institute of Medical Education and Research (PGIMER, Chandigarh) from January 2011 to June 2012. Of the 1,224 patients, 20 males or females were included in the study based on the inclusion and exclusion criteria. The institutional board of PGIMER approved the study before it was initiated.

Purpose

To study the efficacy of ACS in the treatment of unilateral lumbar radiculopathy.

Overview of Literature

Interleukin (IL)-1 appears to be of special importance among the cytokines identified in orthopedic diseases. ACS contains high concentrations of IL-1 receptor antagonist, antagonist to IL-1 in that is a biochemical 'sensitizer' of nerve roots in radiculopathy.

Methods

We included 20 patients with unilateral lumbar radiculopathy after obtaining informed consent. We prepared ACS as described by Meijer et al. Under bi-planar fluoroscopic imaging in anterior-posterior and lateral views, ACS was administered via epidural perineural technique. Patients in both groups were evaluated by quadruple visual analogue scale, straight leg raising test, revised Oswestry disability index, and 12-Item Short Form of Health Survey before and after epidural injections at 3 weeks, 3 months, and 6 months.

Results

There was a statistically significant change in all parameters from pre-injection to first, second, and third follow-up (p<0.001).

Conclusions

ACS can modify the disease course in addition to reducing pain, disability and improving general health.

Use of mesenchymal stem cells or autologous conditioned serum to modulate the inflammatory response to spermatozoa in mares

Current treatments for Persistent mating-induced endometritis such as uterine lavage and oxytocin therapy focus on aiding the uterus in removal of inflammatory products, but these treatments do not modulate the inciting inflammatory response. Biological treatments, such as autologous conditioned serum (ACS) and mesenchymal stem cells (MSCs), have been used in human and veterinary medicine for immunomodulation for over 10 years. The objectives of this project were to evaluate the ability of ACS or MSCs to modulate the inflammatory response to spermatozoa after breeding. Two experiments were performed with six normal mares in each study to evaluate the effects of intrauterine administration of ACS, dexamethasone, or a placebo (experiment 1), or allogeneic MSCs or a placebo (experiment 2) on the inflammatory response to spermatozoa using clinical and biochemical endpoints. Treatment with ACS and MSCs significantly (P < 0.05) reduced the number of neutrophils in the uterine lumen 6 hours after the sperm challenge. An increase (P < 0.05) in the anti-inflammatory cytokine IL-1Ra was observed after treatment with MSCs before exposure to spermatozoa. There was no difference in IL-1Ra concentration in mares treated with ACS, dexamethasone, or a placebo. Mesenchymal stem cells and ACS were able to modulate the immune response to spermatozoa in normal mares. The effect may be due to an increase in IL-1Ra in MSCs-treated mares, but other bioactive molecules may be responsible for the decrease in neutrophils in ACS-treated mares. Autologous conditioned serum and bone-derived culture expanded MSCs were able to modulate the uterine inflammatory response to spermatozoa in normal mares. Treatment with allogeneic stem cells may be beneficial if a similar modulation in inflammatory cytokines occurs in mares affected by persistent mating-induced endometritis.