Effect of Continuous Digital Hypothermia on Lamellar Inflammatory Signaling When Applied at a Clinically-Relevant Timepoint in the Oligofructose Laminitis Model.
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ABSTRACT: Although continuous digital hypothermia (CDH) protects lamellae from injury in the oligofructose (OF) model of sepsis-related laminitis (SRL), conflicting results exist from these studies regarding effects of CDH on lamellar inflammatory events.To determine the effect of CDH on lamellar inflammatory events in normal and OF-treated horses when instituted at a clinically relevant time point (onset of clinical signs of sepsis in this model).Standardbred geldings (n = 15) aged 3-11 years were used.In a randomized, controlled discovery study, animals were administered either OF (OF group, n = 8) or water (CON group, n = 8) by nasogastric tube and CDH was initiated in one forelimb (ICE) 12 hours later. Lamellar tissue samples were collected 24 hours after initiation of CDH (ICE and ambient [AMB] forelimbs). Lamellar mRNA concentrations of inflammatory mediators and lamellar leukocyte numbers were assessed using qPCR and immunohistochemistry, respectively; values from four sample groups (CON AMB, OF AMB, CON ICE, and OF ICE) were analyzed using mixed model linear regression.Although lamellar mRNA concentrations of multiple inflammatory mediators (IL-1?, IL-6, CXCL1, MCP2, COX-2) were increased after OF administration (OF AMB group versus CON AMB; P < 0.05), only 2 inflammatory mediators (IL-6 and COX-2) and lamellar leukocyte numbers were decreased with CDH (OF ICE versus OF AMB; P < 0.05).Continuous digital hypothermia initiated at a time point similar to that commonly used clinically (clinical onset of sepsis) resulted in a more focused inhibition of inflammatory signaling.
Effect of Continuous Digital Hypothermia on Lamellar Inflammatory Signaling When Applied at a Clinically-Relevant Timepoint in the Oligofructose Laminitis Model.
Journal of veterinary internal medicine 20171227 1
<h4>Background</h4>Although continuous digital hypothermia (CDH) protects lamellae from injury in the oligofructose (OF) model of sepsis-related laminitis (SRL), conflicting results exist from these studies regarding effects of CDH on lamellar inflammatory events.<h4>Hypothesis/objectives</h4>To determine the effect of CDH on lamellar inflammatory events in normal and OF-treated horses when instituted at a clinically relevant time point (onset of clinical signs of sepsis in this model).<h4>Anima ...[more]
Project description:BackgroundIn the oligofructose (OF) model of sepsis-related laminitis (SRL), digital hypothermia ("cryotherapy") initiated before the onset of clinical signs is reported not only to limit lamellar injury, but also to cause marked inhibition of lamellar inflammatory signaling.Hypothesis/objectivesBecause hypothermia also has been reported to be protective when not initiated until the onset of lameness in the OF model of SRL, we hypothesized that the lamellar protection conferred by hypothermia is caused by local lamellar inhibition of inflammatory signaling as described when hypothermia was initiated earlier in the disease process.AnimalsEight Standardbred geldings aged 3-11 years with no lameness and no abnormalities of the feet detectable by gross or radiographic examination.MethodsUsing the OF model of SRL, lamellar mRNA concentrations of proinflammatory cytokines, chemokines, and endothelial adhesion proteins were compared between samples from treated limbs (CRYO, submerged in ice water for 36 hour starting at the onset of lameness), untreated limbs (NON-CRYO, opposite limb from CRYO limbs maintained at ambient temperature), and untreated limbs from normal horses in which laminitis was not induced (CON).ResultsAlthough OF administration resulted in increases in lamellar mRNA concentrations of several inflammatory mediators in NON-CRYO limbs (vs CON), digital hypothermia had no significant effect on these increases.Conclusions and clinical importanceThe lack of inflammatory inhibition in lamellar tissue samples in our study indicates that the protective effects of digital hypothermia instituted at the onset of clinical signs of laminitis do not arise from inhibition of inflammatory pathways.
Project description:Bovine laminitis causes substantial economic losses and animal welfare problems in dairy farms worldwide. Previously published studies have reported that the inflammatory response plays a central role in the pathogenesis of the disease. To our knowledge, inflammation associated with bovine laminitis induced by high levels of exposure to oligofructose (OF) has not been reported and characterized. In fact, the disease manifestations in this model closely approximate those of clinical laminitis. The objective of this study was to characterize the inflammatory response in OF-induced bovine laminitis. A total of 12 Chinese Holstein dairy heifers were utilized in this study. The heifers were randomly divided into two groups, treatment (n = 6) and control (n = 6). The treatment group heifers were administered OF solutions via a stomach tube (dose: 17 g/kg of body weight). Upon development of a lameness score of 2 with consecutive positive reactions in the same claw, they would be humanely euthanized. Control heifers were administered deionized water (dose: 2 L/100 kg of body weight) and humanely euthanized at 72 h. Real-time quantitative PCR (qPCR) assays were performed to determine the messenger RNA (mRNA) concentrations of inflammatory mediators in the lamellae. Concentrations of interleukin (IL)-1β, IL-6, IL-8, C-X-C motif chemokine ligand-1 (CXCL-1), macrophage cationic peptide-2 (MCP-2), E-selectin, intercellular adhesion molecule-1 (ICAM-1), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase-1 (iNOS-1), and plasminogen activator inhibitor-1 (PAI-1) were significantly increased (P < 0.05) in the treatment group. No significant difference was found for tumor necrosis factor alpha (TNF-α), IL-10, CXCL-6, and MCP-1. These results demonstrated and characterized the laminar inflammatory response leading to the pathogenesis of bovine laminitis at the early stages.
Project description:The objectives of this study were to examine the clinical response, changes in ruminal bacterial microbiota, and inflammatory response in lamellar tissues during oligofructose-induced laminitis. Ten fistulated sheep were randomly assigned into a control group ( = 5) and a treatment group ( = 5). The treatment group was infused with oligofructose (21 g/kg BW) by rumen cannula, and the control group was sham-treated with saline. Results showed that all 5 sheep treated with oligofructose developed anorexia and diarrhea 8 to 12 h after the administration of oligofructose. By 12 to 24 h after treatment, the treatment group developed lameness and roach back. Compared with the control group, oligofructose administration decreased ( < 0.001) the rumen pH and concentrations of total VFA and increased ( < 0.001) the level of lactic acid in the rumen. Microbial data analysis revealed that oligofructose infusion increased the abundance of ( = 0.009) and ( = 0.008) and decreased the percentage of unclassified Christensenellaceae ( = 0.028), unclassified Ruminococcaceae ( = 0.009), ( = 0.016), unclassified Lachnospiraceae ( = 0.009), and ( = 0.009) compared with the control group. Oligofructose infusion decreased the ACE ( = 0.047) and Shannon ( = 0.009) indices compared with the control group. The histomorphology analysis revealed that oligofructose overload resulted in damage to the dermoepidermal junction in the lamellar tissue of sheep. Quantitative real-time PCR results showed that compared with the control group, the mRNA expression of membrane-type metalloproteinase-1 ( = 0.049) was downregulated whereas the expression of proinflammatory IL-6 ( = 0.004) and matrix metalloprotease-9 ( = 0.037) was upregulated in the lamellar tissues of the oligofructose treatment group. In general, the present study provides the foundation for a sheep model of oligofructose-overload-induced acute laminitis that could be used in later experiments. Our findings suggest that intraruminal infusion of oligofructose altered ruminal microbiota and resulted in acute laminitis and that the inflammatory damage to the lamellae tissue may be related to the upregulation of matrix metalloprotease-9. The information generated will provide more insight into the systemic effects of lameness caused by oligofructose overload in sheep.
Project description:BackgroundLaminitis is a common and serve disease which caused by inflammation and pathological changes of the laminar junction. However, the pathologic mechanism remains unclear. In this study we aimed to investigate changes of the gut microbiota and metabolomics in oligofructose-induced laminitis of horses.ResultsAnimals submitted to treatment with oligofructose had lower fecal pH but higher lactic acid, histamine, and Lipopolysaccharide (LPS) in serum. Meanwhile, oligofructose altered composition of the hindgut bacterial community, demonstrated by increasing relative abundance of Lactobacillus and Megasphaera. In addition, the metabolome analysis revealed that treatment with oligofructose decreased 84 metabolites while 53 metabolites increased, such as dihydrothymine, N3,N4-Dimethyl-L-arginine, 10E,12Z-Octadecadienoic acid, and asparagine. Pathway analysis revealed that aldosterone synthesis and secretion, regulation of lipolysis in adipocytes, steroid hormone biosynthesis, pyrimidine metabolism, biosynthesis of unsaturated fatty acids, and galactose metabolism were significantly different between healthy and laminitis horses. Furthermore, correlation analysis between gut microbiota and metabolites indicated that Lactobacillus and/or Megasphaera were positively associated with the dihydrothymine, N3,N4-Dimethyl-L-arginine, 10E,12Z-Octadecadienoic acid, and asparagine.ConclusionsThese results revealed that disturbance of gut microbiota and changes of metabolites were occurred during the development of equine laminitis, and these results may provide novel insights to detect biomarkers for a better understanding of the potential mechanism and prevention strategies for laminitis in horses.
Project description:BackgroundDigital clinical measures collected via various digital sensing technologies such as smartphones, smartwatches, wearables, ingestibles, and implantables are increasingly used by individuals and clinicians to capture health outcomes or behavioral and physiological characteristics of individuals. Although academia is taking an active role in evaluating digital sensing products, academic contributions to advancing the safe, effective, ethical, and equitable use of digital clinical measures are poorly characterized.ObjectiveWe performed a systematic review to characterize the nature of academic research on digital clinical measures and to compare and contrast the types of sensors used and the sources of funding support for specific subareas of this research.MethodsWe conducted a PubMed search using a range of search terms to retrieve peer-reviewed articles reporting US-led academic research on digital clinical measures between January 2019 and February 2021. We screened each publication against specific inclusion and exclusion criteria. We then identified and categorized research studies based on the types of academic research, sensors used, and funding sources. Finally, we compared and contrasted the funding support for these specific subareas of research and sensor types.ResultsThe search retrieved 4240 articles of interest. Following the screening, 295 articles remained for data extraction and categorization. The top five research subareas included operations research (research analysis; n=225, 76%), analytical validation (n=173, 59%), usability and utility (data visualization; n=123, 42%), verification (n=93, 32%), and clinical validation (n=83, 28%). The three most underrepresented areas of research into digital clinical measures were ethics (n=0, 0%), security (n=1, 0.5%), and data rights and governance (n=1, 0.5%). Movement and activity trackers were the most commonly studied sensor type, and physiological (mechanical) sensors were the least frequently studied. We found that government agencies are providing the most funding for research on digital clinical measures (n=192, 65%), followed by independent foundations (n=109, 37%) and industries (n=56, 19%), with the remaining 12% (n=36) of these studies completely unfunded.ConclusionsSpecific subareas of academic research related to digital clinical measures are not keeping pace with the rapid expansion and adoption of digital sensing products. An integrated and coordinated effort is required across academia, academic partners, and academic funders to establish the field of digital clinical measures as an evidence-based field worthy of our trust.
Project description:The objective of this study was to characterize oligofructose-induced acute rumen lactic acidosis and its consequences in zebu cattle. We used 29 Nellore heifers which were submitted to experimental induction of laminitis by oligofructose excess. During the induction period, the animals underwent clinical examination, including laminitis diagnosis (hoof pressure testing and locomotion score) and blood and ruminal fluid sampling every six hours (over the initial 24 h) and every 12 h (up to 72 h), after the highest dose. Almost half of the animals (48.1%) required treatment with bicarbonate and saline to correct metabolic acidosis and dehydration. Due to this treatment, the animals were analyzed in treated (n = 13) and non-treated (n = 14) groups. The induction model promoted marked reduction in rumen pH, rumen anaerobiosis, carbon dioxide pressure, and increase in rumen lactate, blood osmolarity, and cortisol concentration. The animals treated had lower values of rumen pH and marked dehydration, evidenced by the increase in globular volume and serum urea. The clinical condition caused by excess oligofructose is severe, with the differential of the appearance of ephemeral fever and respiratory compensation against systemic acidosis, in addition to the frequent appearance of laminitis.
Project description:This study was aimed at determining the autophagy activity in the laminar tissue of dairy cows with oligofructose-induced laminitis. Twelve healthy non-pregnant Holstein cows were randomly divided into two groups of six cows each, entitled the control group and the oligofructose overload group (OF group), respectively. At 0 h, cows in the OF group were gavaged with oligofructose (17 g/kg BW) dissolved in warm deionized water (20 mL/kg BW) through an oral rumen tube, and the dairy cows in the control group were gavaged with the same volume of deionized water by the same method. At -72 h before, as well as 0 h, 6 h, 12 h, 18 h, 24 h, 36 h, 48 h, 60 h, and 72 h after perfusion, clinical evaluations of both groups were monitored. After 72 h, the laminar tissues of the dairy cows in both groups were collected to examine the genes and proteins. The gene expression of ATG5, ATG12, and Beclin1 significantly increased (p < 0.05), whereas that of P62 and mTOR significantly decreased (p < 0.01) in the OF group relative to the control group. The protein expression of Beclin-1 significantly increased (p < 0.05), while that of LC3II significantly decreased (p < 0.05) in the OF group relative to the control group. However, the protein expression of P62 non-significantly reduced (p > 0.05) in the OF group comparative to the control group. Furthermore, the distribution of the Beclin1 protein in the laminar tissue significantly increased (p < 0.01), while that of the P62 protein significantly decreased (p < 0.05) in the OF group than the control group. These findings indicate that the imbalanced gene and protein-level status of autophagy-related markers may be the basic cause for the failure of the epidermal attachment. However, a more detailed gene and protein-level study is needed to further clarify the role of autophagy in the pathogenesis of bovine laminitis.
Project description:Endocrinopathic laminitis is pathologically similar to the multi-organ dysfunction and peripheral neuropathy found in human patients with metabolic syndrome. Similarly, endocrinopathic laminitis has been shown to partially result from vascular dysfunction. However, despite extensive research, the pathogenesis of this disease is not well elucidated and laminitis remains without an effective treatment. Here, we sought to identify novel proteins and pathways underlying the development of equine endocrinopathic laminitis. Healthy Standardbred horses (n = 4/group) were either given an electrolyte infusion, or a 48-h euglycemic-hyperinsulinemic clamp. Cardiac and lamellar tissues were analyzed by mass spectrometry (FDR = 0.05). All hyperinsulinemic horses developed laminitis despite being previously healthy. We identified 514 and 709 unique proteins in the cardiac and lamellar proteomes, respectively. In the lamellar tissue, we identified 14 proteins for which their abundance was significantly increased and 13 proteins which were significantly decreased in the hyperinsulinemic group as compared to controls. These results were confirmed via real-time reverse-transcriptase PCR. A STRING analysis of protein-protein interactions revealed that these increased proteins were primarily involved in coagulation and complement cascades, platelet activity, and ribosomal function, while decreased proteins were involved in focal adhesions, spliceosomes, and cell-cell matrices. Novel significant differentially expressed proteins associated with hyperinsulinemia-induced laminitis include talin-1, vinculin, cadherin-13, fibrinogen, alpha-2-macroglobulin, and heat shock protein 90. In contrast, no proteins were found to be significantly differentially expressed in the heart of hyperinsulinemic horses compared to controls. Together, these data indicate that while hyperinsulinemia induced, in part, microvascular damage, complement activation, and ribosomal dysfunction in the lamellae, a similar effect was not seen in the heart. In brief, this proteomic investigation of a unique equine model of hyperinsulinemia identified novel proteins and signaling pathways, which may lead to the discovery of molecular biomarkers and/or therapeutic targets for endocrinopathic laminitis.
Project description:Bovine laminitis leads to huge economic losses and animal welfare problems in the dairy industry worldwide. Numerous studies suggested that several metalloproteinases (MPs) may play vital roles in the failure of epidermal attachment. To the best of our knowledge, the present study is the first to investigate and characterize the gene-level changes in distinct MPs and endogenous inhibitors using oligofructose (OF)-induced bovine laminitis model. The objective of this study was to determine aberrant MPs and related inhibitors of bovine laminitis in gene level, and to provide reasonable directions for the further protein-level research. Twelve normal Chinese Holstein dairy heifers were randomly divided into treatment group (n = 6) and control group (n = 6). The heifers in the treatment group were administered with OF solutions at a dose of 17 g/kg of body weight via a stomach tube. The heifers were then humanely euthanized when they met the criteria of bovine laminitis. The heifers in the control group were administered with deionized water at a dose of 2 L/100 kg of body weight. They humanely euthanized at 72 h. The gene expressions of MPs and endogenous inhibitors, namely, matrix metalloproteinases (MMPs), A disintegrin and metalloproteinases (ADAMs), and A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTs), and tissue inhibitors of metalloproteinases (TIMPs) in the lamellae from two groups were determined via real-time quantitative PCR. The gene expressions of MMP-2, MMP-9, ADAMTS-4, and ADAMTS-5 significantly increased (P < 0.05), whereas that of TIMP-2 significantly decreased (P < 0.05) in the treatment group relative to the control group. No significant difference was found in the gene expressions of ADAM-10, ADAM-17, TIMP-1, and TIMP-3. These results indicated that the gene-level imbalanced condition of MPs and their TIMPs may be the basic cause for the failure of epidermal attachment. At the same time, more detailed protein-level studies would be needed to further clarify the roles of MPs and TIMPs in the pathogenesis of bovine laminitis, especially to MMP-2, MMP-9, ADAMTS-4, ADAMTS-5, TIMP-2 as well as related substrates (e.g., aggrecan and versican).
Project description:Laminitis is one of the most devastating diseases in equine medicine, and although several etiopathogenetic mechanisms have been proposed, few clear answers have been identified to date. Several lines of evidence point towards its underlying pathology as being metabolism-related. In the carbonyl stress pathway, sugars are converted to methylglyoxal (MG)-a highly reactive α-oxoaldehyde, mainly derived during glycolysis in eukaryotic cells from the triose phosphates: D-glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. One common hypothesis is that MG could be synthesized during the digestive process in horses, and excessive levels absorbed into peripheral blood could be delivered to the foot and lead to alterations in the hoof lamellar structure. In the present study, employing an ex vivo experimental design, different concentrations of MG were applied to hoof explants (HE), which were then incubated and maintained in a specific medium for 24 and 48 h. Macroscopic and histological analyses and a separation force test were performed at 24 and 48 h post-MG application. Gene expression levels of matrix metalloproteinase (MMP)-2 and -14 and tissue inhibitor of metalloproteinase (TIMP)-2 were also measured at each time point for all experimental conditions. High concentrations of MG induced macroscopic and histological changes mimicking laminitis. The separation force test revealed that hoof tissue samples incubated for 24 h in a high concentration of MG, or with lower doses but for a longer period (48 h), demonstrated significant weaknesses, and samples were easily separated. All results support that high levels of MG could induce irreversible damage in HEs, mimicking laminitis in an ex vivo model.