IL-17 and its possible role in the pathogenesis of equine osteoarthritis

Osteoartrit (OA) är en vanlig sjukdom både hos människor och hos hästar. Studier tyder på att olika cytokiner, där IL-1β och TNFα tros vara de viktigaste, bidrar till att driva de katabola processer i ledbrosket som man ser vid OA. Syftet med det här arbetet var att undersöka om IL-17 skulle kunna vara ytterligare ett sådan betydelsefull cytokin. IL-17 kan inducera produktion av både NO och PGE2 i ledbrosk, öka produktionen av andra proinflammatoriska cytokiner som IL-1β, IL-6, IL-8 och TNFα, samt uppvisar potent synergi med IL-1β och TNFα. Detta cytokin har också visat sig kunna öka nedbrytningen av- och minska syntesen av extracellulärmatrix i brosket samt öka produktionen av proangiogena faktorer i synovialmembranet. I det fåtal studier som gjorts på människa har man funnit signifikant höjda nivåer av IL-17 i ledvätska hos personer med OA jämfört med de hos friska. I den enda studie på häst som hittats, kunde emellertid inte detta cytokin påvisas i led. IL-17 har förutsättningarna för att kunna vara ett viktig cytokin vid OA men det finns också saker som talar emot. Det skulle också kunna fungera som en bidragande faktor av mindre betydelse. Mer forskning behövs på området innan man kan dra några säkra slutsatser om IL-17:s betydelse för utvecklingen av OA

Compensatory movements in clinically lame horses

Detta examensarbete är en pilotstudie vars syfte var att med hjälp av det objektiva mätsystemet Lameness Locator studera om kompensatoriska hältmekanismer förekommer hos kliniskt halta hästar. Tidigare studier har visat att en inducerad hälta på ett av hästens ben kan resultera i asymmetriska rörelsemönster, så kallad kompensatorisk hälta, även på andra ben. Dessa kompensatoriska hältor är ej smärtutlösta utan försvinner när man reverserar den ursprungliga hältan. I litteraturen beskrivs att en hälta på ett bakben kan ge upphov till en kompensatorisk ipsilateral frambenshälta. Vid hälta på ett framben kan både en ipsilateral och en kontralateral bakbenshälta uppkomma. Totalt ingick 35 hästar i studien varav samtliga var under hältutredning på Universitetssjukhuset vid SLU. Mätvärdena för 11 av hästarna utvärderades och resultatet är att 6 av hästarna uppvisade kompensatoriska hältmekanismer liknande dem som observerats i tidigare studier avseende inducerad hälta. 2 hästar uppvisar något som liknar kompensatoriska hältor men som ej stämmer överens med de mönster för kompensatoriska hältor som man tidigare sett. De tre återstående hästarna uppvisar ingen kompensatorisk hälta. Utvärderingen av en stor andel av hästarnas mätvärden försvårades av att de till synes var initialhalta på mer än ett ben. Resultatet av den här studien visar att det finns kompensatoriska hältmekanismer hos kliniskt halta hästar. Det krävs dock ett betydligt större underlag för att kunna konstatera i vilken utsträckning det förhåller sig så. Mer data krävs också för att kunna dra några slutsatser angående egenskaperna hos dessa kompensatoriska hältmekanismer.This master’s thesis is a pilot study, the aim of which was to study whether compensatory movements resembling lameness are present in clinically lame horses. During the study the objective Lameness Locator system was used. Previous studies have shown that induced lameness in one leg of a horse can cause compensatory movements, which can mimic true lameness, in another limb. These compensatory movements are not pain related and disappear when the induced lameness is reversed. Hindlimb lameness has been described to cause compensatory movements that mimic lameness in the ipsilateral forelimb while forelimb lameness causes corresponding movements in the ipsilateral and/or contralateral hindlimb. A total of 35 horses, presented for lameness evaluation at the University Animal Hospital at the Swedish University of Agricultural Sciences, were included in the present study. The data of 11 out of the 35 horses was selected for further evaluation. This evaluation showed that 6 out of the 8 horses exhibited compensatory movements that resembled those observed in the previous studies. In two of the horses the localization of the compensatory movements was not consistent with that of these previous studies. The three remaining horses showed no compensatory movements. A large proportion of the horses seemed, initially, to be lame on more than one leg, which made the evaluation of the corresponding data much more complicated. The results of this study show that compensatory movements resembling lameness are present in clinically lame horses. However, in order to determine to what extent, a much larger study population is required. A larger study population could also make it possible to draw conclusions about the properties of the compensatory movements

Effect of Speed and Surface Type on Individual Rein and Combined Left-Right Circle Movement Asymmetry in Horses on the Lunge

Differences in movement asymmetry between surfaces and with increasing speed increase the complexity of incorporating gait analysis measurements from lunging into clinical decision making. This observational study sets out to quantify by means of quantitative gait analysis the influence of surface and speed on individual-rein movement asymmetry measurements and their averages across reins (average-rein measurements). Head, withers, and pelvic movement asymmetry was quantified in 27 horses, identified previously as presenting with considerable movement asymmetries on the straight, during trot in hand and on the lunge on two surfaces at two speeds. Mixed linear models (p < 0.05) with horse as the random factor and surface and speed category (and direction) as fixed factors analyzed the effects on 11 individual-rein and average-rein asymmetry measures. Limits of agreement quantified differences between individual-rein and average-rein measurements. A higher number of individual-rein asymmetry variables-particularly when the limb that contributed to movement asymmetry on the straight was on the inside of the circle-were affected by speed (nine variables, all p <= 0.047) and surface (three variables, all p <= 0.037) compared with average-rein asymmetry variables (two for speed, all p <= 0.003; two for surface, all p <= 0.046). Six variables were significantly different between straight-line and average-rein assessments (all p <= 0.031), and asymmetry values were smaller for average-rein assessments. Limits of agreement bias varied between +0.4 and +4.0 mm with standard deviations between 3.2 and 12.9 mm. Fewer average-rein variables were affected by speed highlighting the benefit of comparing left and right rein measurements. Only one asymmetry variable showed a surface difference for individual-rein and average-rein data, emphasizing the benefit of assessing surface differences on each rein individually. Variability in straight-line vs. average-rein measurements across horses and exercise conditions highlight the potential for average-rein measurements during the diagnostic process; further studies after diagnostic analgesia are needed

Prevalence of vertical movement asymmetries at trot in Standardbred and Swedish Warmblood foals

Many horses, just before and during their athletic career, show vertical movement asymmetries, to the same degree as clinically lame horses. It is unknown whether these asymmetries are caused by pain or have alternative explanations, such as inherent biological variation. In the latter case, movement asymmetries would be expected to be present at a very young age. This study aimed to investigate the prevalence of movement asymmetries in foals. Motion analysis, using an inertial measurement unit-based system (Equinosis), was performed on 54 foals (31 Swedish Warmbloods, 23 Standardbreds) during straight-line trot. The foals were between 4–13 weeks old and considered sound by their owners. Differences between the vertical minimum and maximum values recorded for the head (HDmin, HDmax) and pelvis (PDmin, PDmax) between left and right stance were calculated for each stride and an average was computed for each trial. Thresholds for asymmetry were defined as absolute trial mean >6 mm for HDmin and HDmax, and >3 mm for PDmin and PDmax. These thresholds were exceeded for one or several parameters by 83% of Standardbred foals and 45% of Swedish Warmblood foals, demonstrating surprisingly high prevalence of asymmetries in young foals, although the risk of repetitive strain injuries and cumulative risk of trauma injuries was expected to be low in this age group. Standardbred foals showed similar prevalence of asymmetries to that reported previously for yearling Standardbred trotters, so relatively higher prevalence of movement asymmetries may be expected among trotters as a breed. In general, vertical head and pelvic movement asymmetries can be anticipated among foals considered sound by their owners. A better understanding of the aetiology of asymmetries is needed for correct interpretation of objective symmetry measurements in different populations of horses

Objectively measured movement asymmetry in yearling Standardbred trotters

Background Lameness evaluation of Standardbred trotters can be challenging due to discrepancies in observed movement asymmetry between in-hand and track exercise, and between different trotting speeds. There are few studies on objective measurement of movement in Standardbreds, and little knowledge regarding biological variation and clinical significance of measured movement asymmetry in this breed. Objectives To quantify the prevalence and magnitude of objectively measured movement asymmetry in young Standardbred trotters, and identify associations with trainer, sex, height, track type and in-hand measurement prior to or after track trials. Study design Cross-sectional, observational study. Methods A total of 114 Standardbred yearlings were evaluated with a wireless inertial sensor system during trot in-hand and when driven on a track. After exclusions relating to lameness or technical difficulties, 103 horses were included in the study; 77 were evaluated in-hand and on the track, 24 only in-hand and 2 only on the track. Results Front and/or hindlimb parameters were above asymmetry thresholds previously established for other breeds during in-hand trials for 94 (93%) horses and during track trials for 74 (94%) horses. Most horses showed mild asymmetry. A minority of horses (20%) switched side of the asymmetry for one or more parameters between in-hand and track trials. Mixed model analyses revealed no significant effects of trial mode (in-hand or track trial, in-hand trial pre- or post-track trial, straight or oval track), trainer or horse height. Females had a significant but small reduction in asymmetry in one front limb parameter (HDmax) compared with males (1.7 mm, 95% CI 0.18-3.28,P = .03). Main limitations High data variability, reflected in large trial standard deviations, relating mainly to a lack of horse compliance. Conclusions A high proportion of Standardbred yearlings showed movement asymmetries. There was no group-level effect between in-hand and track trials, however, considerable individual variation was observed

Timing of Vertical Head, Withers and Pelvis Movements Relative to the Footfalls in Different Equine Gaits and Breeds

Simple Summary Movement symmetry of the head and pelvis are used to measure lameness in horses in trot. Although head, pelvis and limb movements have been described, less is known about the temporal relationships between them. This information is needed to understand how the movements change with lameness. This is particularly relevant in gaited horses, such as the Icelandic horse that perform gaits such as tolt and pace, which are challenging to evaluate. This study used inertial measurement units to investigate head, withers and pelvis motion relative to limb movements in Icelandic, Warmblood and Iberian horses. Limb movements, together with vertical movements and lowest/highest positions of the head, withers and pelvis were calculated, and the relative timing of the events was compared across breeds. Additionally, data for tolt and pace were collected and evaluated in ridden Icelandic horses. For all gaits except walk and pace, the lowest/highest positions of the head/withers/pelvis were closely temporally related to midstance and hoof-off, respectively. Pelvic and withers total range of motion differed between all breeds. The Icelandic horses showed shorter stride duration and smaller movements of the upper body than the other breeds at trot, which may explain why lameness evaluation in this breed is challenging. Knowledge of vertical motion patterns of the axial body segments is a prerequisite for the development of algorithms used in automated detection of lameness. To date, the focus has been on the trot. This study investigates the temporal synchronization between vertical motion of the axial body segments with limb kinematic events in walk and trot across three popular types of sport horses (19 Warmbloods, 23 Iberians, 26 Icelandics) that are known to have different stride kinematics, and it presents novel data describing vertical motion of the axial body segments in tolting and pacing Icelandic horses. Inertial measurement unit sensors recorded limb kinematics, vertical motion of the axial body at all symmetrical gaits that the horse could perform (walk, trot, tolt, pace). Limb kinematics, vertical range of motion and lowest/highest positions of the head, withers and pelvis were calculated. For all gaits except walk and pace, lowest/highest positions of the pelvis and withers were found to be closely related temporally to midstance and start of suspension of the hind/fore quarter, respectively. There were differences in pelvic/withers range of motion between all breeds where the Icelandic horses showed the smallest motion, which may explain why lameness evaluation in this breed is challenging

Improving gait classification in horses by using inertial measurement unit (IMU) generated data and machine learning

For centuries humans have been fascinated by the natural beauty of horses in motion and their different gaits. Gait classification (GC) is commonly performed through visual assessment and reliable, automated methods for real-time objective GC in horses are warranted. In this study, we used a full body network of wireless, high sampling-rate sensors combined with machine learning to fully automatically classify gait. Using data from 120 horses of four different domestic breeds, equipped with seven motion sensors, we included 7576 strides from eight different gaits. GC was trained using several machine-learning approaches, both from feature-extracted data and from raw sensor data. Our best GC model achieved 97% accuracy. Our technique facilitated accurate, GC that enables in-depth biomechanical studies and allows for highly accurate phenotyping of gait for genetic research and breeding. Our approach lends itself for potential use in other quadrupedal species without the need for developing gait/animal specific algorithms

Timing of Vertical Head, Withers and Pelvis Movements Relative to the Footfalls in Different Equine Gaits and Breeds

Knowledge of vertical motion patterns of the axial body segments is a prerequisite for the development of algorithms used in automated detection of lameness. To date, the focus has been on the trot. This study investigates the temporal synchronization between vertical motion of the axial body segments with limb kinematic events in walk and trot across three popular types of sport horses (19 Warmbloods, 23 Iberians, 26 Icelandics) that are known to have different stride kinematics, and it presents novel data describing vertical motion of the axial body segments in tölting and pacing Icelandic horses. Inertial measurement unit sensors recorded limb kinematics, vertical motion of the axial body at all symmetrical gaits that the horse could perform (walk, trot, tölt, pace). Limb kinematics, vertical range of motion and lowest/highest positions of the head, withers and pelvis were calculated. For all gaits except walk and pace, lowest/highest positions of the pelvis and withers were found to be closely related temporally to midstance and start of suspension of the hind/fore quarter, respectively. There were differences in pelvic/withers range of motion between all breeds where the Icelandic horses showed the smallest motion, which may explain why lameness evaluation in this breed is challenging

Evaluation of vertical movement asymmetries in riding horses: relevance to equine orthopaedics

Disorders of the locomotor apparatus are very common in sports horses. Pain and dysfunction associated with these conditions have a negative impact on horse welfare. The main component in lameness evaluation is detection of vertical movement asymmetries but the inter-rater agreement among veterinarians is low. Therefore, modern methods of detection and quantification of movement asymmetry have been developed. The aim of this thesis was to help improve equine welfare by providing a better scientific basis for interpretation of movement asymmetries. This could support riders and veterinarians in detecting lameness at an early stage and improve orthopaedic diagnostics. To investigate a possible association between movement asymmetry and presence of painful orthopaedic conditions, NSAID (meloxicam) treatment was performed in asymmetrically moving, but presumed sound horses. Interestingly, this did not decrease the magnitude of asymmetry. Other reasons for asymmetric movement and the clinical efficacy of treatment with meloxicam in relation to a potentially present pathology therefore need to be addressed. The influence of the rider’s seating style on vertical movement symmetry in trot was evaluated in 26 horses. ‘Rising trot’ induced systematic changes, the most prominent being a decreased pelvic rise, mimicking push-off lameness in the hindlimb of the diagonal on which the rider was sitting in ‘rising trot’. The potential of the relationship between the direction of head and withers movement asymmetry parameters to assist in locating the primary lame limb was investigated in horses with induced lameness. The findings were then verified in horses with naturally occurring lameness. The results showed that head and withers movement asymmetry parameters indicate the same forelimb in horses with forelimb lameness, but indicate opposite forelimbs in horses with hindlimb lameness and compensatory head movement asymmetry. The results presented in this thesis extend existing knowledge about the origin and significance of movement asymmetries in riding horses and compensatory mechanisms in lame horse

Perceived sidedness and correlation to vertical movement asymmetries in young warmblood horses

The prevalence of vertical asymmetries is high in "owner-sound" warmblood riding horses, however the origin of these asymmetries is unknown. This study investigated correlations between vertical asymmetries and motor laterality. Young warmblood riding horses (N = 65), perceived as free from lameness were evaluated on three visits, each comprising objective gait analysis (inertial measurement units system) and a rider questionnaire on perceived sidedness of the horse. A subgroup (N = 40) of horses were also subjected to a forelimb protraction preference test intended as an assessment of motor laterality. We hypothesized associations between vertical asymmetry and motor laterality as well as rider-perceived sidedness. Vertical asymmetry was quantified as trial means of the stride-by-stride difference between the vertical displacement minima and maxima of the head (HDmin, HDmax) and pelvis (PDmin, PDmax). Laterality indexes, based on counts of which limb was protracted, and binomial tests were used to draw conclusions from the preference tests. In the three visits, 60-70% of horses exhibited vertical asymmetries exceeding clinically used thresholds for & GE;1 parameter, and 22% of horses exhibited a side preference in the preference test as judged by binomial tests. Linear mixed models identified a weak but statistically significant correlation between perceived hindlimb weakness and higher PDmin values attributable to either of the hindlimbs (p = 0.023). No other statistically significant correlations to vertical asymmetry were seen for any of the questionnaire answers tested. Tests of correlation between the absolute values of laterality index and asymmetry parameters (HDmin, HDmax, PDmin, PDmax) identified a weak correlation (p = 0.049) with PDmax, but when accounting for the direction of asymmetry and motor laterality, no correlations were seen for either of the asymmetry parameters. No convincing evidence of associations between vertical asymmetries and motor laterality were seen and further studies investigating motor laterality and the origin of vertical asymmetries are needed