Effects of exposure to chronic ergot alkaloids on phenylephrine contractile response of maternal pedal artery, umbilical artery, and umbilical vein in pregnant ewes.

Ergot alkaloids are known to cause devastating effects in livestock. The objectives of this study were to evaluate the effects of prolonged ergot exposure on selected vasculature in pregnant sheep and to examine the role of alpha-1 adrenergic receptors in mediating these effects. Twelve 60-day pregnant sheep were randomly placed into control and exposure groups (n = 6/group). Ergot-contaminated feed pellets were given orally once a day for 45 d to the exposure group [46.6 µg/kg body weight (BW) total ergot alkaloids]. The control group (Ctl) received ergot-free pellets. The maternal pedal artery from the left hindlimb and the umbilical artery and vein were dissected and mounted in a tissue bath. The vascular contractile response to a cumulatively increasing dose of phenylephrine (PE) in the exposure group (Exp) was compared with the control groups. Chronic exposure to ergot alkaloids resulted in a 70.6% and 91.3% increase in PE contractile response in the umbilical artery (Ctl EC50 = 3.962 × 10-6; Exp EC50 = 1.161 × 10-6, P < 0.0001) and the umbilical vein (Ctl EC50 = 7.889 × 10-6; Exp EC50 = 6.801 × 10-7, P < 0.0001), respectively, but there was no increase in the pedal artery (P = 0.3927), when compared to the control group. Fetal weight in the ergot-exposed group was significantly lower than in the control group (Ctl 3.3 ± 0.17 kg; Exp 2.07 ± 0.13 kg, P = 0.0002). The increase in contractile response in the umbilical vein may result in decreased blood supply to the fetus causing decreased fetal weight. Negative impact was seen at significantly lower levels of ergot alkaloids than what is currently allowed by Canadian standards, which suggests that these limits should be reevaluated to ensure livestock safety.

Les alcaloïdes de l'ergot sont connus pour avoir des effets dévastateurs sur le bétail. Les objectifs de cette étude étaient d'évaluer les effets d'une exposition prolongée à l'ergot sur une vascularisation sélectionnée chez les brebis gestantes et d'examiner le rôle des récepteurs alpha-1 adrénergiques dans la médiation de ces effets. Douze brebis gestantes de 60 jours ont été placées au hasard dans des groupes témoins et exposés (n = 6/groupe). Des granulés alimentaires contaminés par l'ergot ont été administrés par voie orale une fois par jour pendant 45 jours au groupe exposé [46,6 µg/kg de poids corporel (PC) d'alcaloïdes totaux de l'ergot]. Le groupe témoin (Ctl) a reçu des granulés sans ergot. L'artère pédieuse maternelle du membre postérieur gauche et l'artère et la veine ombilicales ont été disséquées et montées dans un bain de tissu. La réponse contractile vasculaire à une dose cumulative croissante de phényléphrine (PE) dans le groupe exposé (Exp) a été comparée aux groupes témoins. L'exposition chronique aux alcaloïdes de l'ergot a entraîné une augmentation de 70,6 % et de 91,3 % de la réponse contractile de l'PE dans l'artère ombilicale (Ctl EC50 = 3,962 × 10−6; Exp EC50 = 1,161 × 10−6, P < 0,0001) et la veine ombilicale (Ctl EC50 = 7,889 × 10−6; Exp EC50 = 6,801 × 10−7, P < 0,0001), respectivement, mais il n'y a pas eu d'augmentation dans l'artère pédieuse (P = 0,3927), par rapport au groupe témoin. Le poids foetal du groupe exposé à l'ergot était significativement plus faible que celui du groupe témoin (Ctl 3,3 ± 0,17 kg; Exp 2,07 ± 0,13 kg, P = 0,0002). L'augmentation de la réponse contractile dans la veine ombilicale peut entraîner une diminution de l'apport sanguin au foetus, ce qui entraîne une diminution du poids foetal. Un impact négatif a été observé à des niveaux significativement plus faibles d'alcaloïdes de l'ergot que ce qui est actuellement autorisé par les normes canadiennes, ce qui suggère que ces limites devraient être réévaluées pour assurer la sécurité du bétail.(Traduit par Docteur Serge Messier).

An in vitro testicular organoid model for the study of testis morphogenesis, somatic cell maturation, endocrine function, and toxicological assessment of endocrine disruptors.

Male reproductive capacity has fallen considerably in recent decades; in addition, the incidence of testicular cancer has increased in many developed countries. The cause of this phenomenon is unknown, but environmental toxicants are considered a major contributing factor. To study potential reproductive toxicants, robust in vitro testis models are needed. We have recently established a porcine testis organoid system with a high resemblance to the architectures of innate testis tissue. Here, we further investigated the testis morphogenesis, cell maturation, and endocrine function of the testis organoids. We also challenged this system with abiraterone, a steroidogenic inhibitor, to validate its suitability as an in vitro platform for endocrine toxicology tests. Our results showed that the testis cells in the organoids reorganize into testis cordal structures, and the cordal relative areas increase in the organoids over time of culture. Moreover, the diameters and cell numbers per cross-section of the cordal structures increased over time. Interestingly, Sertoli cells in the organoids gradually underwent maturational changes by showing increased expression of androgen receptors, decreased expression of the anti-müllerian hormone, and formation of the blood-testis barrier. Next, we confirmed that the organoids respond to hormonal stimulation and release multiple sex hormones, including testosterone, estradiol, and progesterone. Finally, we showed that the production of testosterone and estradiol in this system can be inhibited in response to the steroidogenic inhibitor. Taken together, our organoid system provides a promising in vitro platform for male reproductive toxicology studies on testis morphogenesis, somatic cell maturation, and endocrine production.

Time-course of oral toxicity to contaminated groundwater in male Sprague Dawley rats.

Assessing toxicity of complex mixtures of contaminants from industrial sites with historic and ongoing contamination remains a challenge for risk assessors. Groundwater from a pesticide packaging site in Canada containing a complex mixture of known and unknown contaminants was examined in male rats to determine the target organ toxicity. This study determined the time-course of toxicity (7, 14, 28, and 60 days) following ad libitum oral exposure to 0.05% v/v contaminated groundwater compared to tap water (control) in male Sprague Dawley rats (n=5 /group/time). Exposure to groundwater resulted in inflammation, indicated by a statistically significant increase in plasma lymphocyte and neutrophil counts on days 7 and 60, respectively, but a reduction in the plasma alpha 2 macroglobulin levels by day 60. Gonadotoxicity was indicated by a reduced Johnsen score (grading spermatogenesis) in all exposed groups at all time points, while seminiferous epithelial height was reduced on days 7, 14, and 28 compared to controls. Plasma testosterone was reduced in exposed groups on days 7 and 28, accompanied by elevated testicular lipid peroxidation at all time points compared to control. In contrast, lipid peroxidation in the lungs from exposed rats was elevated on days 7, 14, and 28. Plasma symmetric dimethylarginine was elevated on day 14 in the exposed group indicating renal impairment. Taken together, these results indicate that testes, kidney, immune and lung are target organs for the contaminated groundwater from this industrial site. The current study highlights the challenge in hazard assessment for complex mixtures and highlights the need for effects-directed analysis and the continued, albeit limited, use of animal models in toxicity testing.

The C-8-S-isomers of ergot alkaloids - a review of biological and analytical aspects.

Ergot alkaloids are secondary metabolites that are produced by fungi and contaminate cereal crops and grasses. The ergot alkaloids produced by Claviceps purpurea are the most abundant worldwide. The metabolites exist in two configurations, the C-8-R-isomer (R-epimer) and the C-8-S-isomer (S-epimer). These two configurations can interconvert to one another. Ergot alkaloids cause toxic effects after consumption of ergot-contaminated food and feed at various concentrations. For bioactivity reasons, the C-8-R-isomers have been studied to a greater extent than the C-8-S-isomer since the C-8-S-isomers were considered biologically inactive. However, recent studies suggest the contrary. Analytical assessment of ergot alkaloids now includes the C-8-S-isomers and high concentrations of specific C-8-S-isomers have been identified. The inclusion of the C-8-S-isomer in regulatory standards is reviewed. This review has identified that further research into the C-8-S-isomers of ergot alkaloids is warranted. In addition, the inclusion of the C-8-S-isomers into regulatory recommendations worldwide for food and feed should be implemented. The objectives of this review are to provide an overview of historic and current studies that have assessed the C-8-S-isomers. Specifically, this review will compare the C-8-R-isomers to the C-8-S-isomers with an emphasis on the biological activity and analytical assessment.

Examining the subchronic (28-day) effects of aqueous Cd-BaP co-exposure on detoxification capacity and cardiac function in adult zebrafish (Danio rerio).

The present study aimed to examine the effects of environmentally relevant concentrations of cadmium (Cd) and Benzo[a]Pyrene (BaP) in the adult zebrafish (Danio rerio). To this end, fish were exposed to either 1 or 10 µg/L Cd or 0.1 or 1 µg/L BaP in isolation, or a co-exposure containing a mixture of the two toxicants. Our results showed extensive modulation of the expression of key antioxidant genes (GPx, SOD1, catalase), detoxifying genes (MT1, MT2, CYP1A1) and a stress biomarker (HSP70) differing between control, single toxicant groups and co-exposure groups. We additionally carried out histopathological analysis of the gills, liver, and hearts of exposed animals, noting no differences in tissue necrosis or apoptosis. Finally, we carried out ultrasonographic analysis of cardiac function, noting a significant decrease of E-wave peak velocity and end diastolic volume in exposed fish. This in turn was accompanied by a decrease in stroke volume and ejection fraction, but not cardiac output in co-exposed fish. The present study is the first to demonstrate that a subchronic aqueous exposure to a Cd-BaP mixture can extensively modulate detoxification capacity and cardiac function in adult zebrafish in a tissue-specific manner.

The Impact of Storage Temperature and Time on Ergot Alkaloid Concentrations.

Ergot sclerotia produce toxic secondary metabolites, ergot alkaloids, that infect cereal crops and grasses. Ergot alkaloids have two isomeric configurations: the C-8-R-isomer (R-epimer), and the C-8-S-isomer (S-epimer). Ergot contaminated matrices, such as cereal grains or grasses, may be stored for extended periods at various temperatures before being analyzed, utilized, or consumed. This study assessed the concentration of six common ergot alkaloids in both configurations found in naturally contaminated wheat over time (one, two, and four months) at different temperatures (room temperature, +4 °C, and -20 °C) using ultra-high-performance liquid chromatography-tandem mass spectrometry. The data indicate that the total ergot concentration within a natural contaminated sample varies over time at room temperature, +4 °C, and -20 °C. The total ergot concentration increased until month two, and decreased at month four, independent of temperature (p < 0.05). The total R-epimer concentration appeared to be less stable over time than the total S-epimer concentration. The changes in the total R and total S-epimer concentrations may have been caused by changes in the ergocristine and ergocristinine concentrations, respectively. Time and temperature should be considered when storing potentially contaminated matrices in a laboratory or practical agriculture situations. Quantification of ergot contaminated matrices should occur prior to their use to ensure the most reliable estimates of the concentration of ergot.

Investigation of the relationship between ergocristinine and vascular receptors.

Ergot alkaloids are secondary metabolites that exist in two configurations, the C-8-R-isomer (R-epimer), and the C-8-S-isomer (S-epimer). Toxic effects of ergot, such as vasoconstriction, have been primarily attributed to the R-epimer bioactivity, as compared to the S-epimer. Recent studies demonstrated potential bioactivity of S-epimers. Therefore, further cost-effective investigations of the S-epimers are needed. The present study investigated the S-epimer - vascular receptor binding relationship. An in silico molecular docking approach, utilizing AutoDock Vina and DockThor, was used to determine if the S-epimer (ergocristinine) binds to vascular receptors and to compare the binding affinity and interactions to the corresponding R-epimer (ergocristine) and a structural analogue (lysergic acid amide). The binding energy (kcal/mol) of ergocristinine was - 9.7 or - 11.0 to the serotonin (5-HT) 2 A receptor and - 8.7 or - 11.4 to the alpha 2 A adrenergic receptor, depending on the software used. A hydrogen bond was formed between ergocristinine and amino acid residues of the 5-HT 2 A and alpha 2 A adrenergic receptor binding sites, with bond lengths of 3.10 Å and 3.28 Å, respectively. Binding affinities and molecular interactions among the ligands to each receptor differed. Different affinities and interactions may relate to differences in the chemical structures. The binding affinities and strong molecular interactions of the S-epimer to vascular receptors may contribute to the observed physiological manifestations that occur after ergot alkaloid exposure. The results of the present study suggest further investigation on the receptor binding of the S-epimers of ergot alkaloids.

Correlation between E-cadherin expression and tumor grade, proliferation, microvascular density, and apoptosis in canine cutaneous squamous cell carcinoma.

E-cadherin is an adhesion molecule expressed on epithelial surfaces. Loss of its expression is described in cancerous tissues. Here, we examined the expression of E-cadherin in canine cutaneous squamous cell carcinoma (SCC) and determined its association with tumor grade (TG), proliferation index (PI), apoptosis index (AI), and intra-tumoral microvascular density (iMVD) in archived samples. Thirty-six cutaneous SCC samples (archived from 2014 to 2019) were graded and E-cadherin level, Ki67 (PI), von Willebrand factor (iMVD), and apoptosis (AI) were determined immunohistochemically. Tumor grades were assigned as Grade 1 (n = 18), Grade 2 (n = 16), and Grade 3 (n = 2). Of the 36 tumors, 21 were digital and 15 were from other locations, including the tail, neck, ear, and elbow. The median E-cadherin score decreased statistically (P = 0.03) with an increase in TG. There was a negative association between median E-cadherin score and TG (r = -0.445, P = 0.013), AI (r = -0.342, P = 0.08), and PI (r = -0.459, P = 0.016). The median E-cadherin score was significantly higher in digital SCC compared to SCC from other locations (P = 0.035). In conclusion, a negative association was observed between TG, PI, AI, and E-cadherin.

La E-cadhérine est une molécule d'adhésion exprimée sur les surfaces épithéliales. La perte de son expression est décrite dans les tissus cancéreux. Ici, nous avons examiné l'expression de la E-cadhérine dans le carcinome épidermoïde cutané canin (SCC) et déterminé son association avec le grade de la tumeur (TG), l'indice de prolifération (PI), l'indice d'apoptose (AI) et la densité microvasculaire intra-tumorale (iMVD) dans des échantillons archivés. Trente-six échantillons de SCC cutanés (archivés de 2014 à 2019) ont été classés et le niveau d'E-cadhérine, Ki67 (PI), le facteur von Willebrand (iMVD) et l'apoptose (AI) ont été déterminés par immunohistochimie. Les grades de tumeur ont été attribués au grade 1 (n = 18), au grade 2 (n = 16) et au grade 3 (n = 2). Sur les 36 tumeurs, 21 étaient digitales et 15 provenaient d'autres localisations, notamment la queue, le cou, l'oreille et le coude. Le score médian de la E-cadhérine a diminué statistiquement (P = 0,03) avec une augmentation des TG. Il y avait une association négative entre le score médian de la E-cadhérine et TG (r = −0,445, P = 0,013), AI (r = −0,342, P = 0,08) et PI (r = −0,459, P = 0,016). Le score médian de la E-cadhérine était significativement plus élevé dans les SCC des doigts par rapport au SCC provenant d'autres sites (P = 0,035). En conclusion, une association négative a été observée entre TG, PI, AI et E-cadhérine.(Traduit par Docteur Serge Messier).

Correlation of hepatic copper levels, rhodanine scores and histological diagnosis in archived canine liver samples.

The liver is the main storage site for copper. Excess copper accumulation, however, is a risk factor for the development of chronic hepatitis in dogs. Mass spectrometry or rhodanine staining are frequently used methods to assess copper levels in the liver. The association was studied between analytic hepatic copper levels and rhodanine scores in archived canine formalin-fixed-paraffinembedded liver sections from 2014 to 2021 with various diagnoses. Thirty-six (N = 36) liver samples with analytic interpretation of toxic (n = 12), high normal (n = 17), and normal (n = 7) copper levels were selected for the study. Rhodanine staining for each of these samples was graded (scale: 1 to 5), and the association was determined between actual liver copper levels and rhodanine scores and histological diagnoses (chronic hepatitis or other diagnoses). The analytic copper level and rhodanine scores were significantly higher (P < 0.05) in samples designated as toxic compared to normal. There was a significant association between hepatic copper levels and rhodanine scores (P < 0.05). Rhodanine score, but not the actual liver copper levels were significantly (P < 0.05) associated with chronic hepatitis versus other diagnoses. Rhodanine scores of ≥ 1.89 were statistically significant predictors of chronic hepatitis. It was concluded from this study that actual liver copper levels are positively associated with rhodanine scores and rhodanine scores can be a useful predictor of chronic hepatitis.

Le foie est le principal site de stockage du cuivre. Cependant, une accumulation excessive de cuivre est un facteur de risque pour le développement d'une hépatite chronique chez le chien. La spectrométrie de masse ou la coloration à la rhodanine sont des méthodes fréquemment utilisées pour évaluer les niveaux de cuivre dans le foie. L'association entre les niveaux analytiques de cuivre hépatique et les scores de rhodanine a été étudiée dans des sections de foie de chien archivées fixées au formol et incluses dans de la paraffine de 2014 à 2021 avec divers diagnostics. Trente-six (N = 36) échantillons de foie avec interprétation analytique des niveaux de cuivre toxiques (n = 12), normaux élevés (n = 17) et normaux (n = 7) ont été sélectionnés pour l'étude. La coloration à la rhodanine de chacun de ces échantillons a été évaluée (échelle : 1 à 5) et l'association a été déterminée entre les niveaux réels de cuivre dans le foie et les scores de rhodanine et les diagnostics histologiques (hépatite chronique ou autres diagnostics). Les niveaux analytiques de cuivre et les scores de rhodanine étaient significativement plus élevés (P < 0,05) dans les échantillons désignés comme toxiques par rapport à la normale. Il y avait une association significative entre les niveaux de cuivre hépatique et les scores de rhodamine (P < 0,05). Le score de rhodanine, mais pas les niveaux réels de cuivre dans le foie, était significativement (P < 0,05) associé à l'hépatite chronique par rapport à d'autres diagnostics. Les scores de rhodanine ≥ 1,89 étaient des prédicteurs statistiquement significatifs de l'hépatite chronique. Il a été conclu à partir de cette étude que les niveaux réels de cuivre dans le foie sont positivement associés aux scores de rhodanine et que les scores de rhodanine peuvent être un prédicteur utile de l'hépatite chronique.(Traduit par Docteur Serge Messier).

Ammonization of the R- and S-Epimers of Ergot Alkaloids to Assess Detoxification Potential.

Detoxification of ergot-contaminated feed by ammonia would be a practical application, given that ammonia is routinely used in the agriculture industry. To assess the effects of ammonia on ergot alkaloids, natural ergot-contaminated wheat was ammoniated. The total concentration of ergot alkaloids (R- and S-epimers) decreased after exposure to ammonia (8-29%). Separately, the total R-epimers decreased in concentration (40-66%), whereas the total S-epimers increased (21-81%). Specific ergot alkaloids demonstrated degradation and/or epimerization after exposure to ammonia, potentially associated with structural differences, and influenced the total concentrations observed. Ammonization of ergot standards resulted in potential degradation products and epimerization, supporting the above results. The use of ultrahigh-performance liquid chromatography-tandem mass spectrometry provides an updated assessment of the detoxification potential of ammonia for ergot alkaloids and the quantification of the S-epimers. Ammonia alters the R- and S-epimers of ergot alkaloids, which may lead to a potential practical detoxification process of ergot-contaminated feed.

Sustained vascular contractile response induced by an R- and S-epimer of the ergot alkaloid ergocristine and attenuation by a noncompetitive antagonist.

Vasoconstriction is a known effect associated with ergot alkaloid consumption. The vascular contractile responses are often sustained for an extended period after exposure. Ergot alkaloids exist in two molecular configurations, the C-8-(R)-isomer (R-epimer) and the C-8-(S)-isomer (S-epimer). The sustained vascular contractile response to the R-epimers has been studied previously, unlike the S-epimers which are thought to be biologically inactive. Additionally, antagonists have been utilized to attenuate the vascular contraction associated with the R-epimers of ergot alkaloids utilizing ex vivo techniques. This study utilized an arterial tissue bath to examine and compare the sustained vascular contractile response attributed to ergocristine (R) and ergocristinine (S) using dissected bovine metatarsal arteries. The contractile blocking effect of a noncompetitive alpha-adrenergic antagonist, phenoxybenzamine (POB), was also investigated in precontracted arteries. Arteries (n = 6/epimer) were exposed to a single dose of ergocristine or ergocristinine (1 × 10-6 M in buffer). Each of the epimer doses was followed by a POB (1 × 10-3 M) or methanol (control) treatment at 90 min and the response was observed for another 90 min. Both epimers produced a sustained contractile response over the 180-min incubation period in the control groups. The R-epimer caused a greater sustained contractile response from 60 to 180 min post epimer exposure, compared to the S-epimer (P < 0.05, generalized estimating equations, independent t-test). Phenoxybenzamine caused a decrease in the contractile response induced by ergocristine and ergocristinine from 105 to 180 min, compared to the control (P < 0.05, generalized estimating equations, paired t-test). Overall, these results demonstrate the presence of a sustained vascular contractile response attributed to the R- and S-epimer of an ergot alkaloid with differences in contractile response between the epimers, suggesting differences in receptor binding mechanisms. Furthermore, this study demonstrated that a noncompetitive antagonist could attenuate the sustained arterial contractile effects of both ergot configurations ex vivo. Additional investigation into S-epimers of ergot alkaloids is needed. This research contributes to the understanding of the ergot epimer-vascular receptor binding mechanisms, which may support the investigation of different approaches of minimizing ergot toxicity in livestock.

Ergot alkaloids cause blood vessels to contract when contaminated feed is consumed by animals. Vascular contraction often remains for a prolonged period and involves the binding of ergot to specific receptors in the blood vessels. This study assessed and compared the sustained contraction of cow arteries after exposure to two forms of an ergot alkaloid, namely, ergocristine and ergocristinine. The effects of a specific receptor blocker, phenoxybenzamine, on the vascular contraction induced by these forms were also examined. This study showed that both forms of ergot caused a sustained contraction of cow arteries but to different magnitudes. Differences in contraction could be related to differences in how each form of ergot binds to receptors. The receptor blocker decreased the sustained contractile response of both forms of ergot. Further understanding of how the different forms of ergot bind to receptors, and how to decrease the adverse effects, may help mitigate the toxic effects of ergotism.

Prolonged absorption and susceptibility to enterohepatic circulation after oral administration of ergot alkaloids in ewes.

The objective of this study was to evaluate the pharmacokinetics profile of ergot alkaloids when administered to sheep orally. Although ergot alkaloids frequently contaminate animal feed, current understanding of their pharmacokinetics in animals cannot adequately predict toxicity. Blood samples were collected from ewes at 0.5, 1, 3, 5, and 12 h after oral exposure to 4 ergot alkaloids: ergocornine, ergocristine, ergocryptine, and ergosine, followed by serum analysis of these alkaloids using high performance liquid chromatography and tandem mass spectrometry. The alkaloids showed extended absorption time, in addition to clear signs of enterohepatic circulation. This pharmacokinetic profile suggests potential enhanced toxicity in animals with disorders related to secretion of bile acid. It may also explain the high susceptibility of sheep to ergot poisoning compared to other species. An extended sampling protocol (> 12 h) is necessary, however, to identify the pharmacokinetic properties of ergot alkaloids in ewes. In conclusion, ewes exposed to ergot alkaloids showed a prolonged absorption phase and enterohepatic circulation, which is in contrast with human ergot pharmacokinetics.

L'objectif de cette étude était d'évaluer le profil pharmacocinétique des alcaloïdes de l'ergot lorsqu'ils sont administrés à des moutons par voie orale. Bien que les alcaloïdes de l'ergot contaminent fréquemment les aliments pour animaux, la compréhension actuelle de leur pharmacocinétique chez les animaux ne permet pas de prédire de manière adéquate la toxicité. Des échantillons de sang ont été prélevés chez les brebis à 0,5, 1, 3, 5 et 12 h après exposition orale à quatre alcaloïdes de l'ergot : ergocornine, ergocristine, ergocryptine et ergosine, suivi d'une analyse sérique de ces alcaloïdes par chromatographie liquide à haute performance et spectrométrie de masse en tandem. Les alcaloïdes ont montré un temps d'absorption prolongé, en plus de signes évidents de circulation entérohépatique. Ce profil pharmacocinétique suggère une toxicité potentiellement accrue chez les animaux présentant des troubles liés à la sécrétion d'acide biliaire. Cela peut également expliquer la forte sensibilité des moutons à l'empoisonnement par l'ergot par rapport aux autres espèces. Un protocole de prélèvement étendu (> 12 h) est cependant nécessaire pour identifier les propriétés pharmacocinétiques des alcaloïdes de l'ergot chez les brebis. En conclusion, les brebis exposées aux alcaloïdes ont montré une phase d'absorption prolongée et une circulation entérohépatique, ce qui contraste avec la pharmacocinétique de l'ergot chez l'humain.(Traduit par Docteur Serge Messier).

Vasoactive Effects of Acute Ergot Exposure in Sheep.

Ergotism is a common and increasing problem in Saskatchewan's livestock. Chronic exposure to low concentrations of ergot alkaloids is known to cause severe arterial vasoconstriction and gangrene through the activation of adrenergic and serotonergic receptors on vascular smooth muscles. The acute vascular effects of a single oral dose with high-level exposure to ergot alkaloids remain unknown and are examined in this study. This study had two main objectives; the first was to evaluate the role of α1-adrenergic receptors in mediating the acute vasocontractile response after single-dose exposure in sheep. The second was to examine whether terazosin (TE) could abolish the vascular contractile effects of ergot alkaloids. Twelve adult female sheep were randomly placed into control and exposure groups (n = 6/group). Ergot sclerotia were collected and finely ground. The concentrations of six ergot alkaloids (ergocornine, ergocristine, ergocryptine, ergometrine, ergosine, and ergotamine) were determined using HPLC/MS at Prairie Diagnostic Services Inc., (Saskatoon, SK, Canada). Each ewe within the treatment group received a single oral treatment of ground ergot sclerotia at a dose of 600 µg/kg BW (total ergot) while each ewe in the control group received water. Animals were euthanized 12 h after the treatment, and the pedal artery (dorsal metatarsal III artery) from the left hind limb from each animal was carefully dissected and mounted in an isolated tissue bath. The vascular contractile response to phenylephrine (PE) (α1-adrenergic agonist) was compared between the two groups before and after TE (α1-adrenergic antagonist) treatment. Acute exposure to ergot alkaloids resulted in a 38% increase in vascular sensitivity to PE compared to control (Ctl EC50 = 1.74 × 10-6 M; Exp EC50 = 1.079 × 10-6 M, p = 0.046). TE treatment resulted in a significant dose-dependent increase in EC50 in both exposure and control groups (p < 0.05 for all treatments). Surprisingly, TE effect was significantly more pronounced in the ergot exposed group compared to the control group at two of the three concentrations of TE (TE 30 nM, p = 0.36; TE 100 nM, p < 0.001; TE 300 nM, p < 0.001). Similar to chronic exposure, acute exposure to ergot alkaloids results in increased vascular sensitivity to PE. TE is a more potent dose-dependent antagonist for the PE contractile response in sheep exposed to ergot compared to the control group. This study may indicate that the dry gangrene seen in sheep, and likely other species, might be related to the activation of α1-adrenergic receptor. This effect may be reversed using TE, especially at early stages of the disease before cell death occurs. This study may also indicate that acute-single dose exposure scenario may be useful in the study of vascular effects of ergot alkaloids.

Evaluation of La(XT), a novel lanthanide compound, in an OVX rat model of osteoporosis.

PURPOSE: The purpose of this study was to evaluate the efficacy and toxicity of a novel lanthanum compound, La(XT), in an ovariectomized (OVX) rat model of osteoporosis. METHODS: Twenty-four ovariectomized female Sprague Dawley rats were divided into 3 groups receiving a research diet with/without treatment compounds (alendronate: 3 mg/kg; La(XT) 100 mg/kg) for three months. At the time of sacrifice, the kidney, liver, brain, lung and spleen were collected for histological examination. The trabecular bone structure of the tibiae was evaluated using micro-CT and a three-point metaphyseal mechanical test was used to evaluate bone failure load and stiffness. RESULTS: No significant differences were noted in plasma levels of calcium, phosphorus, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) between the La(XT) treatment compared to the non-treated OVX group. Alendronate-treated animals (positive control) showed higher BV/TV, Tb.N and lower Tb.Th and Tb.Sp when compared to the non-treated OVX group. Mechanical analysis indicated that stiffness was higher in the alendronate (32.88%, p = 0.04) when compared to the non-treated OVX group. Failure load did not differ among the groups. CONCLUSIONS: No kidney or liver toxicities of La(XT) treatments were found during the three-month study. The absence of liver and kidney toxicity with drug treatment for 3 months, as well as the increased trabecular bone stiffness are encouraging for the pursuit of further studies with La(XT) for a longer duration of time.

Evaluation of metallothionein and Ki-67 expression in chronic cholangiohepatitis in cats.

Chronic cholangiohepatitis (CCH) is a common pathological condition in cats with a guarded prognosis and unknown etiology. Recently, in human medicine, there has been increased interest in enhancing liver defense mechanisms as an effective treatment strategy to control liver diseases that have a poor prognosis. Metallothionein (MT) is a ubiquitous protein, which has been widely researched for its role in liver defense through heavy metal detoxification, neutralization of reactive oxygen species, and liver regeneration. In this study, immunohistochemistry was used to evaluate the role of MT in CCH and hepatocellular regeneration in 34 cats histologically diagnosed with this condition by assessing the correlation between hepatocellular MT and Ki-67 (marker for cellular proliferation) expression with histological parameters of CCH, such as inflammation, fibrosis, and bile duct proliferation. Statistical analysis was performed using the Spearman-rank correlation test. A significant positive correlation was observed between inflammation and the number of MT-positive hepatocytes (r = 0.36, P = 0.03) and MT labelling intensity (r = 0.37, P = 0.03). In 16 of 34 cases (47%) MT labelling intensity was noted to be pronounced towards the centrilobular zone and very weak or absent towards the portal zone. The results suggest that MT is induced in the liver during chronic inflammatory conditions, which could be speculated as a host defensive mechanism to protect the liver from inflammation-mediated liver injury. Therapeutic interventions utilizing MT, therefore, may have a positive effect on cats with chronic cholangiohepatitis.

La cholangiohépatite chronique (CCH) est une affection pathologique courante chez les chats avec un pronostic réservé et une étiologie inconnue. Récemment, en médecine humaine, il y a eu un intérêt accru pour l'amélioration des mécanismes de défense hépatique en tant que stratégie de traitement efficace pour contrôler les maladies du foie qui ont un mauvais pronostic. La métallothionéine (MT) est une protéine omniprésente, qui a été largement étudiée pour son rôle dans la défense du foie par la détoxification des métaux lourds, la neutralisation des espèces réactives de l'oxygène et la régénération du foie. Dans cette étude, l'immunohistochimie a été utilisée pour évaluer le rôle de la MT dans la CCH et la régénération hépatocellulaire chez 34 chats diagnostiqués histologiquement avec cette condition en évaluant la corrélation entre l'expression hépatocellulaire de la MT et du Ki-67 (marqueur de la prolifération cellulaire) avec les paramètres histologiques de la CCH, comme l'inflammation, la fibrose et la prolifération des voies biliaires. L'analyse statistique a été réalisée à l'aide du test de corrélation de rang de Spearman. Une corrélation positive significative a été observée entre l'inflammation et le nombre d'hépatocytes MT-positifs (r = 0,36, P = 0,03) et l'intensité de marquage MT (r = 0,37, P = 0,03). Dans 16 des 34 cas (47 %), l'intensité du marquage MT était prononcée vers la zone centrolobulaire et très faible ou absente vers la zone porte. Les résultats suggèrent que la MT est induite dans le foie pendant les états inflammatoires chroniques, ce qui pourrait être supposé comme un mécanisme de défense de l'hôte pour protéger le foie contre les lésions hépatiques induites par l'inflammation. Les interventions thérapeutiques utilisant la MT peuvent donc avoir un effet positif sur les chats atteints de cholangiohépatite chronique.(Traduit par Docteur Serge Messier).

Validation of a New Sensitive Method for the Detection and Quantification of R and S-Epimers of Ergot Alkaloids in Canadian Spring Wheat Utilizing Deuterated Lysergic Acid Diethylamide as an Internal Standard.

Ergot sclerotia effect cereal crops intended for consumption. Ergot alkaloids within ergot sclerotia are assessed to ensure contamination is below safety standards established for human and animal health. Ergot alkaloids exist in two configurations, the R and S-epimers. It is important to quantify both configurations. The objective of this study was to validate a new ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for quantification of six R and six S-epimers of ergot alkaloids in hard red spring wheat utilizing deuterated lysergic acid diethylamide (LSD-D3) as an internal standard. Validation parameters such as linearity, limit of detection (LOD), limit of quantification (LOQ), matrix effects, recovery and precision were investigated. For the 12 epimers analyzed, low LOD and LOQ values were observed, allowing for the sensitive detection of ergot epimers. Matrix effects ranged between 101-113% in a representative wheat matrix. Recovery was 68.3-119.1% with an inter-day precision of <24% relative standard deviation (RSD). The validation parameters conform with previous studies and exhibit differences between the R and S-epimers which has been rarely documented. This new sensitive method allows for the use of a new internal standard and can be incorporated and applied to research or diagnostic laboratories.

Assessment of the vasoactive effects of the (S)-epimers of ergot alkaloids in vitro.

Ergot alkaloids are produced by the fungus Claviceps purpurea and their levels are carefully monitored in animal and human diets due to their harmful effects and widespread contamination of cereal crops. Ergot alkaloids exist in two forms known as the (R)- and (S)-epimers with only the former being monitored in diets in North America. The (S)-epimers of ergot alkaloids are thought to be biologically inactive and, therefore, harmless. A major mechanism by which the (R)-epimers of ergot alkaloids produce their toxic effect is through vasoconstriction. Therefore, the objective of this study was to examine the vasoactivity potential (contractile response) of four (S)-epimers, namely ergocryptinine, ergocristinine, ergocorninine, and ergotaminine utilizing an in vitro arterial tissue bath system. Bovine metatarsal arteries (n = 6, ergocryptinine and ergocorninine; n = 6, ergocristinine and ergotaminine; n = 6 arteries/(S)-epimer, total n = 12) were collected from healthy mixed-breed beef steers immediately after slaughter, cut into 3-mm arterial cross sections, and suspended in a tissue bath with continuously oxygenated Krebs-Henseleit buffer. To assess the contractile response of each (S)-epimer, a cumulative contractile dose-response curve was constructed by incubating arteries with increasing concentrations (1 × 10-11 to 1 × 10-6 M) of that (S)-epimer. Contractile responses were recorded as grams of tension and were normalized to an initial contraction of phenylephrine. Contrary to the widespread belief, all tested (S)-epimers were found vasoactive and produced a concentration-dependent arterial contractile response similar to what has been reported for the (R)-epimers. The arterial contractile response to ergotaminine was strongest and was significantly greater than that of ergocryptinine and ergocristinine at the highest concentration used (P ≤ 0.01). Our results indicate that the (S)-epimers are biologically active and are likely harmful similar to the (R)-epimers. The levels of (S)-epimers should be carefully monitored in human and animal diets worldwide.

Concentrations and deficiencies of minerals in cattle submitted to a diagnostic laboratory in Saskatchewan from 2003-2012: A retrospective study.

Trace mineral analyses of samples submitted to Prairie Diagnostic Services laboratory from Saskatchewan cattle between 2003 and 2012 were examined, with the objective of describing trends and reporting concentrations and deficiencies of minerals. Deficiencies were observed with copper, iron, manganese, magnesium, zinc, and cobalt. Deficiency was most commonly seen in copper, followed by iron, manganese, and magnesium accounting for 47.2%, 15.1%, 13.0%, and 10.8% of deficiencies, respectively. Deficiency in cobalt was least common followed by zinc accounting for 4.2% and 9.7% of deficiencies, respectively. The following minerals were also analyzed: barium, beryllium, bismuth, cadmium, chromium, antimony, tin, molybdenum, strontium, thallium, and vanadium. Submissions from 1434 animals were reviewed and a diagnosis of mineral deficiency was made for 509 animals with 92 of these having multiple deficiencies. There were significant differences in the number of deficient animals by year (P = 0.001), age group (P = 0.01), but not month (P = 0.109) or soil type (P = 0.172).

Concentrations et déficiences en minéraux dans des échantillons bovins soumis à un laboratoire de diagnostic en Saskatchewan entre 2003­2012 : une étude rétrospective. Les résultats d'analyse pour les oligo-éléments dans des échantillons provenant de bovins en Saskatchewan soumis au laboratoire de Prairie Diagnostic Services entre 2003 et 2012 furent examinés, avec comme objectif de décrire les tendances et rapporter les concentrations et déficiences en minéraux. Des déficiences furent observées pour le cuivre, le fer, le manganèse, le magnésium, le zinc, et le cobalt. Les déficiences étaient les plus fréquemment rencontrées avec le cuivre, suivi du fer, manganèse, et magnésium représentant 47,2 %, 15,1 %, 13,0 %, et 10,8 % des déficiences, respectivement. La déficience en cobalt était moins fréquente suivie par le zinc et représentant 4,2 % et 9,7 % des déficiences, respectivement. Les minéraux suivants furent également analysés : barium, béryllium, bismuth, cadmium, chromium, antimoine, étain, molybdène, strontium, thallium, et vanadium. Les soumissions provenant de 1434 animaux furent revues et un diagnostic de déficience en minéraux fut posé chez 509 animaux, avec 92 de ceux-ci ayant des déficiences multiples. Il y avait des différences significatives dans le nombre d'animaux déficients par année (P = 0,001), les groupes d'âge (P = 0,01), mais pas pour les mois (P = 0,109) ou le type de sol (P = 0,172).(Traduit par Dr Serge Messier).

Feline infectious peritonitis in a cat presented because of papular skin lesions.

A 19-week-old neutered male domestic shorthair cat was examined because of multiple raised pruritic skin lesions along the dorsal head and back. Histopathology of biopsies of the lesions detected nodular pyogranulomatous dermatitis with vasculitis and necrosis, leading to a suspicion of feline infectious peritonitis (FIP). Postmortem examination revealed gross lesions consistent with FIP. Histopathologic lesions and positive immunohistochemical staining for feline coronavirus in multiple tissues, including the skin, confirmed the diagnosis of FIP. The current case was similar to previous cases, except for the initial presentation with cutaneous lesions and no other clinical signs, which had not been reported previously.

Péritonite infectieuse féline chez un chat présenté pour des lésions cutanées papuleuses. Un chat domestique commun mâle stérilisé âgé de 19 semaines a été examiné en raison de multiples lésions cutanées prurigineuses épaisses le long de la tête dorsale et du dos. L'histopathologie des biopsies des lésions a détecté une dermatite pyogranulomateuse nodulaire avec vasculite et nécrose, ce qui a soulevé des soupçons de péritonite infectieuse féline (PIF). L'examen post mortem a révélé des lésions macroscopiques conformes à la PIF. Les lésions histopathologiques et la coloration immunohistochimique positive pour le coronavirus félin dans plusieurs tissus, y compris la peau, ont confirmé le diagnostic de PIF. Le cas actuel est semblable aux cas antérieurs, sauf pour la présentation initiale avec des lésions cutanées et aucun autre signe clinique, ce qui n'avait pas été signalé précédemment.(Traduit par Isabelle Vallières).