Metabolism during anaesthesia and recovery in colic and healthy horses: a microdialysis study

<p>Abstract</p> <p>Background</p> <p>Muscle metabolism in horses has been studied mainly by analysis of substances in blood or plasma and muscle biopsy specimens. By using microdialysis, real-time monitoring of the metabolic events in local tissue with a minimum of trauma is possible. There is limited information about muscle metabolism in the early recovery period after anaesthesia in horses and especially in the colic horse. The aims were to evaluate the microdialysis technique as a complement to plasma analysis and to study the concentration changes in lactate, pyruvate, glucose, glycerol, and urea during anaesthesia and in the recovery period in colic horses undergoing abdominal surgery and in healthy horses not subjected to surgery.</p> <p>Methods</p> <p>Ten healthy university-owned horses given anaesthesia alone and ten client-owned colic horses subjected to emergency abdominal surgery were anaesthetised for a mean (range) of 230 min (193–273) and 208 min (145–300) respectively. Venous blood samples were taken before anaesthesia. Venous blood sampling and microdialysis in the gluteal muscle were performed during anaesthesia and until 24 h after anaesthesia. Temporal changes and differences between groups were analysed with an ANOVA for repeated measures followed by Tukey Post Hoc test or Planned Comparisons.</p> <p>Results</p> <p>Lactate, glucose and urea, in both dialysate and plasma, were higher in the colic horses than in the healthy horses for several hours after recovery to standing. In the colic horses, lactate, glucose, and urea in dialysate, and lactate in plasma increased during the attempts to stand. The lactate-to-pyruvate ratio was initially high in sampled colic horses but decreased over time. In the colic horses, dialysate glycerol concentrations varied considerably whereas in the healthy horses, dialysate glycerol was elevated during anaesthesia but decreased after standing. In both groups, lactate concentration was higher in dialysate than in plasma. The correspondence between dialysate and plasma concentrations of glucose, urea and glycerol varied.</p> <p>Conclusion</p> <p>Microdialysis proved to be suitable in the clinical setting for monitoring of the metabolic events during anaesthesia and recovery. It was possible with this technique to show greater muscle metabolic alterations in the colic horses compared to the healthy horses in response to regaining the standing position.</p

Metabolism before, during and after anaesthesia in colic and healthy horses

<p>Abstract</p> <p>Background</p> <p>Many colic horses are compromised due to the disease state and from hours of starvation and sometimes long trailer rides. This could influence their muscle energy reserves and affect the horses' ability to recover. The principal aim was to follow metabolic parameter before, during, and up to 7 days after anaesthesia in healthy horses and in horses undergoing abdominal surgery due to colic.</p> <p>Methods</p> <p>20 healthy horses given anaesthesia alone and 20 colic horses subjected to emergency abdominal surgery were anaesthetised for a mean of 228 minutes and 183 minutes respectively. Blood for analysis of haematology, electrolytes, cortisol, creatine kinase (CK), free fatty acids (FFA), glycerol, glucose and lactate was sampled before, during, and up to 7 days after anaesthesia. Arterial and venous blood gases were obtained before, during and up to 8 hours after recovery. Gluteal muscle biopsy specimens for biochemical analysis of muscle metabolites were obtained at start and end of anaesthesia and 1 h and 1 day after recovery.</p> <p>Results</p> <p>Plasma cortisol, FFA, glycerol, glucose, lactate and CK were elevated and serum phosphate and potassium were lower in colic horses before anaesthesia. Muscle adenosine triphosphate (ATP) content was low in several colic horses. Anaesthesia and surgery resulted in a decrease in plasma FFA and glycerol in colic horses whereas levels increased in healthy horses. During anaesthesia muscle and plasma lactate and plasma phosphate increased in both groups. In the colic horses plasma lactate increased further after recovery. Plasma FFA and glycerol increased 8 h after standing in the colic horses. In both groups, plasma concentrations of CK increased and serum phosphate decreased post-anaesthesia. On Day 7 most parameters were not different between groups. Colic horses lost on average 8% of their initial weight. Eleven colic horses completed the study.</p> <p>Conclusion</p> <p>Colic horses entered anaesthesia with altered metabolism and in a negative oxygen balance. Muscle oxygenation was insufficient during anaesthesia in both groups, although to a lesser extent in the healthy horses. The post-anaesthetic period was associated with increased lipolysis and weight loss in the colic horses, indicating a negative energy balance during the first week post-operatively.</p

Equine Post Anaesthetic Myositis: Muscular Post Ischaemic Hyperaemia Measured by Laser Doppler Flowmetry

Measurements of muscular microcirculation in horses anaesthetised with halothane were performed by laser Doppler flowmetry. Variations of microcirculation in the compressed and uncompressed triceps brachii were measured when horses were positioned in dorsal recumbency after a prolonged period in lateral recumbency. A significant post ischaemic hyperaemia was recorded in horses which developed a post anaesthetic myositis

Is Sclerostin Glycoprotein a Suitable Biomarker for Equine Osteochondrosis?

Osteochondrosis (OC) disease appears to be multifactorial in origin, including skeletal growth rates, nutrition, endocrinological factors, exercise, biomechanics, and other environmental factors. Endocrinological and metabolic factors seem to have an important role in the pathogeny of OC like the Wnt signaling pathway. One of the regulators in the Wnt signaling pathway is the sclerostin glycoprotein. The aim of this study was to investigate the sclerostin blood concentration according to the evolution of the disease, the environment, and the age but also its use as a possible biomarker for OC disease. Relation between age and sclerostin concentrations was calculated by a linear regression. A relation was found between age and sclerostin concentrations, but also a significant relation between age and the sclerostin concentrations was observed for two subgroups (OC affected and healthy). Evolution of the disease related to the sclerostin concentration was assessed with two logistic regressions (risk of developing OC and recovery of existing lesions), but not any significance was found. In conclusion, these results show that, despite the possible link of sclerostin with the OC pathogenesis through the Wnt pathway, circulating levels of this glycoprotein shall not be used as a biomarker for the disease. Besides, more studies are needed to fully understand the functions of sclerostin in the equine specie since it may play an important role in bone homeostasis. © 2017 Elsevier Inc

Postnatal growth after between-breeds embryo transfer in horses

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Intrauterine growth restriction after between-breed embryo transfer is associated with strong alterations in placental structure and function in horses

ln equids, placentationis diffus'e and the nutrient supply to the fetus is deterrnined byuterine size, which is correlated with materna!size. The size of the mare affects fetai development as shawn by embryo transfer (ET) between Panics and Thoroughbreds. In tum, insulin sensitivity in the newbom tüal and subsequent postnatal growth rate are affected. We enhanced or restricted fetal growth through ETusing Pony (P), Saddlebred (S), and Draft (D) horses and investigated placenta! morpho!ogy, structure, and fonction at tenn. Control pregnancies of P-P (n = 21), S-S (n = 28), and D-D (n = 8) were obtained by Al. Enhanced and restricted pregnancies were obtained by transferring P (P-D, n = 6) and S embryos (S-D, n = 8) into D mares orS embryos into P mares (S-P, n = 6), respective]y. Placenta!weight and surface were recorded at delivery. Samples were collected for stereology and RT-qPCR analysis of expression of genes involved in placenta!growth, vascularization, and nutrient transport. Housekeeping genes were RPL32, SCAMP3, and B2M. Data were analysed by Kruskal-Wallis followed by Dunn's post hoc test. Placenta!weight and surface were increased in S-S and in D-D compared with P-P, whereas S-S and D-D were not different. No histological changes were observed among contrais, but most genes had their expression decreased in P-P compared with S-S andD-D. The P-D foals hada 57% increased birthweight with heavier and largerplacentas than P-P foals. The S-D foals were similar to both S-S and D-D in te1ms ofbirthweight and placenta!weight and surface. No major modifications in placenta!histology or transcript levels were observed in both enhanced groups. In contrast, S-P foals had a 37% decreased birthweight with lighter and smaller placentas compared with S-S and S-D foals. Therewas no gross histological difference betweenS-P and S-S but the microcotyledonary surfacedensity was higher in S-P compared with S-D. Moreover, the expression of IGF2, !GF2R, SLC2Al, and eNOS was decreased in S-P compared with S-S. There was no difference in gene expression between S-P and P-P. In conclusion, intrauterine growth restriction led to marked changes in placenta!morphology, histology, and gene expression. The increased microcotyledonary surface density suggests a lengthening ofvillî, which could increase feto-maternal contact surface as a compensatory mechanism for the restricted uterine capacity. Surprisingly, placenta! adaptation to the restricted intrauterine enviromnent in S-P induced gene profiles resembling that of control P, whereas no difference was observed in enhanced pregnancies