Laminitis Group Research Articles

Characterization of the Bacterial Community of Rumen in Dairy Cows with Laminitis.

Laminitis is the inflammation of the lamella, and it has caused great economic loss to the dairy industry and attracted wide attention around the world. In recent years, microbiota are considered to play a significant role in various diseases processes. Therefore, our study aimed to explore the characteristics of ruminal microbiota in laminitis cows. The serum of bovines with or without laminitis was collected to detect concentrations of lipopolysaccharide (LPS), lactic acid, and histamine, and ruminal fluid was collected for 16S rDNA sequence analysis. The results showed a significant increase in LPS and lactic acid levels in the laminitis group compared to the control group cows. In addition, a higher abundance of Candidatus Saccharimonas, Saccharofermentans, Erysipelotrichaceae UCG-009 genus, Acetobacter pasteurianus, Clostridium papyrosolvens, Ruminococcaceae bacterium AE2021, Porphyromonas crevioricanis, Pseudomonas boreopolis, Pseudomonas psychrotolerans, Rothia nasimurium, and Rothia pickettii was detected in the rumen fluid of laminitis bovines. In conclusion, this article confirms that there are differences in rumen microbiota between healthy and laminitis bovines. The elevated abundance of bacteria that enrich acid-enhancing metabolites, as well as increase the concentration of lactic acid and LPS, could be harmful factors to bovines and increase the risk of laminitis.

Histomorphometry of the placental vasculature and microcotyledons in Thoroughbred mares with chronic laminitis

The objective of this study was to assess the placental vasculature and microcotyledons in pregnant mares with chronic laminitis. Twenty-six pregnant mares were enrolled in the study, 13 had chronic laminitis (Laminitis Group) and 13 were healthy mares (Healthy Group). Arterial systolic pressure and heart rate were measured in the last 30 days of gestation. After foaling, the fetal membranes were grossly evaluated and samples were harvested for histopathologic examination. All mares had digitalized images taken from chorioallantois for histomorphometry analyses (software-NIH ImageJ). Images were assessed for: (i) arterioles from the allantoic region: total and lumen vascular diameter and vascular wall thickness; (ii) microcotiledonary and capillary area/field. Mares in the Laminitis Group showed hypertension, shorter gestational length, lower placental weight and lower birthweight (p < 0.05) foal in comparison with mares in the Healthy Group. Laminitis mares had a reduction of vascular lumen diameters in the uterine body and pregnant horn (p < 0.05), vascular wall thickening in the pregnant horn (p < 0.05) and smaller capillary area/field in the microcotyledons of uterine body and pregnant horn (p < 0.05). In conclusion, pregnant mares with chronic laminitis presented signs of hypertension syndrome, and vascular abnormalitities in placental vessels such as reduction in the vascular lumen and capillary area in the microcotyledones, and thickening of the vascular wall. Foals born from mares with chronic laminitis showed lower birth weight and shorter gestation lengths.

A preliminary study of grazing intakes of ponies with and without a history of laminitis

One possible factor involved in the aetiology of laminitis is grazing intake. Whilst some studies have looked at grazing intake in healthy animals, there has been little comparison made between animals with and without a history of laminitis. The aim of this study was to compare grazing intake between health animals and those with a known history of laminitis. Sixteen mature grass-kept (maintained at grass 24h a day) native breed ponies from World Horse Welfare in Norfolk were used in the study, which was conducted in the month of July for a period of 12 days. All animals were grazed under identical conditions. Grazing areas were of that suitable for the management of animals predisposed to laminitis (for ethical reasons) and therefore herbage mass was low (Yield: 124kg dry matter/ha; sward height of 1–2cm). Faecal samples were collected from 8 clinically normal horses (NOR) and from 8 that were predisposed to laminitis (LAM) in July 2005. Grazing intake was measured using the alkane technique. Dry matter intakes (DMI) per kilogram bodyweight were low in both groups of animals: 1.32±0.31 percent versus 1.62±0.74 percent for NOR and LAM, respectively. There was no difference in DMI between the two groups of ponies (4.43 versus 4.25kg/day for NOR and LAM, respectively). Mean DMI per kilogram bodyweight per day were 1.32 and 1.62 for NOR and LAM, respectively (20 percent difference).There was a greater variability of DMI within the LAM group with intakes ranging from 0.81 to 2.36 percent bodyweight. The low DMI values were attributed to the overgrazed nature of the pasture used in this study, which was unavoidable due to the welfare issues associated with grazing overweight, laminitis-prone horses on good grazing pasture. Further work is required with a larger study population grazing pastures with greater herbage mass.

Role of insulin during the development of oligofructose (OF)-induced equine laminitis

Abstract Horses (n = 20) were divided into 2 groups: oligofructose (OF)-induced equine laminitis group (group OF; n = 11) which received 10 g/kg b.w. of OF dissolved in 4 L water via nasogastric intubation, and control group (NS; n = 9) which received 4 L of saline. Blood was collected at 4 h intervals over 72 h study period and analysed by ELISA, kinetic limulus amoebocyte lysate assay, and glucose-oxidase methods. The level of insulin changed significantly in horses which received OF (P &lt; 0.01); there was a significant negative correlation between the level of adiponectin and insulin over time. The results suggested that insulin may play an important role in the development of OF-induced equine laminitis by altering the level of endothelin-1 and nitric oxide.

Pyrosequencing of 16S rRNA genes in fecal samples reveals high diversity of hindgut microflora in horses and potential links to chronic laminitis

BackgroundThe nutrition and health of horses is closely tied to their gastrointestinal microflora. Gut bacteria break down plant structural carbohydrates and produce volatile fatty acids, which are a major source of energy for horses. Bacterial communities are also essential for maintaining gut homeostasis and have been hypothesized to contribute to various diseases including laminitis. We performed pyrosequencing of 16S rRNA bacterial genes isolated from fecal material to characterize hindgut bacterial communities in healthy horses and those with chronic laminitis.ResultsFecal samples were collected from 10 normal horses and 8 horses with chronic laminitis. Genomic DNA was extracted and the V4-V5 segment of the 16S rRNA gene was PCR amplified and sequenced on the 454 platform generating a mean of 2,425 reads per sample after quality trimming. The bacterial communities were dominated by Firmicutes (69.21% control, 56.72% laminitis) and Verrucomicrobia (18.13% control, 27.63% laminitis), followed by Bacteroidetes, Proteobacteria, and Spirochaetes. We observed more OTUs per individual in the laminitis group than the control group (419.6 and 355.2, respectively, P = 0.019) along with a difference in the abundance of two unassigned Clostridiales genera (P = 0.03 and P = 0.01). The most abundant bacteria were Streptococcus spp., Clostridium spp., and Treponema spp.; along with unassigned genera from Subdivision 5 of Verrucomicrobia, Ruminococcaceae, and Clostridiaceae, which together constituted ~ 80% of all OTUs. There was a high level of individual variation across all taxonomic ranks.ConclusionsOur exploration of the equine fecal microflora revealed higher bacterial diversity in horses with chronic laminitis and identification of two Clostridiales genera that differed in abundance from control horses. There was large individual variation in bacterial communities that was not explained in our study. The core hindgut microflora was dominated by Streptococcus spp., several cellulytic genera, and a large proportion of uncharacterized OTUs that warrant further investigation regarding their function. Our data provide a foundation for future investigations of hindgut bacterial factors that may influence the development and progression of chronic laminitis.

Gene expression in the lamellar dermis–epidermis during the developmental phase of carbohydrate overload-induced laminitis in the horse

Objective Gene expression in the lamellar dermis and epidermis was compared between healthy horses and horses in the developmental phase of carbohydrate overload-induced laminitis, in order to better understand the local biochemical and cellular events involved in the pathogenesis of laminitis. Animals Six healthy adult horses, with no history or clinical evidence of laminitis. Procedures Horses were randomly divided into two groups: control ( n = 3) and laminitis ( n = 3). Control horses received no treatment and were humanely euthanatized at the same time as the laminitis group. Horses in the laminitis group were given oligofructose (10 g/kg bwt by nasogastric tube) and humanely euthanatized 24–30 h later, before any clinical signs of laminitis were apparent. Sections of lamellar dermis and epidermis were harvested from the dorsal hoof wall of each horse immediately after death and cryopreserved until analysis. A bovine microarray chip, comprising approximately 15,000 genes, was used to compare gene expression between laminitis and control groups. Results A total of 155 genes were up-regulated in the laminitis group. No genes were down-regulated. Genes coding for the production of pro-inflammatory biochemical or cellular processes and those involved in protein degradation/turnover predominated. Several regulatory or anti-inflammatory genes were also up-regulated. Conclusions and clinical relevance Generation of inflammatory mediators within the lamellar tissues occurred before the development of substantial dermal–epidermal separation, inflammatory infiltrate, or vascular changes, and before the horses began showing signs of foot pain. While further studies are needed, early and targeted anti-inflammatory therapy may halt or prevent the development of laminitis in at-risk individuals.

Influência da heparina sódica na ocorrência de laminite eqüina induzida por sobrecarga de carboidratos

Avaliou-se a eficiência da infusão intravenosa de heparina sódica (100UI/kg/8h, a partir de 24h após o fornecimento de carboidrato, até completar 48h) no controle da laminite eqüina experimentalmente induzida por sobrecarga de carboidrato (17,6g de amido de milho/kg de peso corpóreo). Foram utilizados 15 eqüinos adultos, distribuídos em três grupos experimentais: GI (grupo-controle); GII (grupo laminite) e GIII (grupo laminite+heparina). Posteriormente ao fornecimento de carboidrato, os animais foram submetidos a exames físicos e laboratoriais durante um período de 48 horas. Ao final do experimento, os animais foram submetidos à eutanásia pela aplicação intravenosa de 5ml de maleato de acepromazina seguida de 1g de tiopental sódico e 1 litro de solução saturada de KCl para a obtenção de amostras de tecidos dos cascos, necessárias ao exame histológico. Os animais de GII e GIII, submetidos à sobrecarga de carboidratos, desenvolveram laminite, exibindo claudicação 12 e 24h após o fornecimento de carboidrato, respectivamente, bem como aumentos da freqüência cardíaca e do tempo de preenchimento capilar. As alterações histológicas, semelhantes em GII e GIII, eram do tipo degenerativo, como adelgaçamento de lâminas epidérmicas, retração, achatamento e deslocamento de lâminas dérmicas, vacuolização epidérmica e desorganização do tecido epidérmico. A infusão da heparina sódica não preveniu ou atenuou a degeneração laminar.

Cyclooxygenase Expression in the Early Stages of Equine Laminitis: A Cytologic Study

Background:Recent reports indicate increased amounts of mRNA from inflammation‐related genes in the prodromal stage of laminitis.Hypothesis:Cyclooxygenase‐1 (COX‐1) and cyclooxygenase‐2 (COX‐2) undergo distinct patterns of expression in equine laminae in the developmental stage (DEV) and acute clinical stage (LAM) of laminitis.Animals:Horses selected from an outbred population were placed into 1 of 4 groups: DEV (n = 5), CON‐3h (control group for DEV, n = 5), LAM (n = 5) and CON‐10h (control group for LAM, n = 5).Methods:Laminar and skin samples were obtained from (1) animals either undergoing leukopenia (DEV) or the onset of clinical signs of laminitis (LAM) after black walnut extract (BWE) administration and (2) animals either 3 (CON‐3h) or 10 (CON‐10h) hours after administration of water. Real‐time quantitative polymerase chain reaction (RT‐qPCR), immunoblotting, and immunohistochemical analysis were performed for COX‐1 and COX‐2.Results:Upon immunohistochemical analysis of all 4 groups, COX‐2 was expressed by most viable epithelial cells in both laminae and skin. COX‐1 exhibited similar epithelial expression to COX‐2 in skin epidermis, but was expressed exclusively in the basal layer of laminar epidermis. COX‐1 protein was not detectable in dermal vasculature of equine skin or laminae, whereas COX‐2 was present in endothelial and vascular smooth muscle cells of dermal vasculature in both skin and laminae in all groups. A marked increase in laminar COX‐2 protein concentrations was detected on immunoblotting in the DEV group, although a lesser increase was observed in the LAM group.Conclusions and Clinical Importance: COX‐2 protein expression is markedly increased in the resident laminar cell types in the developmental stage of BWE‐induced laminitis.

DOPPLER SONOGRAPHIC EVALUATION OF THE DIGITAL BLOOD FLOW IN HORSES WITH LAMINITIS OR SEPTIC PODODERMATITIS

The aim of this study was to evaluate the use of Doppler ultrasonography to monitor vascular blood flow dynamics in defined diseases of the equine digit in a noninvasive way. Doppler sonography was used to evaluate medial digital artery blood flow in eight horses with septic pododermatitis and four horses with laminitis in comparison with 10 horses of a control group. Doppler sonographic measurement and lameness examinations were performed in lame horses before treatment (day 0) and at 3, 6, and 9 days following treatment. Before treatment, blood flow velocities, arterial diameter, and flow volume were significantly higher in the lame horses, while pulsatility indices (PIs) were significantly lower (P < 0.05). Compared with the control group, there was no significant difference of resistive indices (RI) in the septic pododermatitis group, but these indices were significantly lower in the laminitis group. No significant difference between the two lame groups was recorded. After treatment, blood flow velocities and flow volume decreased significantly and PIs increased significantly in both lame groups, while RI and arterial diameter did not change. No correlation between Doppler parameters and the degree of lameness was found. Doppler sonography can be used to monitor vascular blood flow dynamics in horses suffering from septic pododermatitis and laminitis, while blood flow velocities and PI can serve as parameters for monitoring the course of the disease.