Localization of the succinate receptor in the distal nephron and its signaling in polarized MDCK cells

When the succinate receptor (SUCNR1) is activated in the afferent arterioles of the glomerulus it increases renin release and induces hypertension. To study its location in other nephron segments and its role in kidney function, we performed immunohistochemical analysis and found that SUCNR1 is located in the luminal membrane of macula densa cells of the juxtaglomerular apparatus in close proximity to renin-producing granular cells, the cortical thick ascending limb, and cortical and inner medullary collecting duct cells. In order to study its signaling, SUCNR1 was stably expressed in Madin-Darby Canine Kidney (MDCK) cells, where it localized to the apical membrane. Activation of the cells by succinate caused Gq and Gi-mediated intracellular calcium mobilization, transient phosphorylation of extracellular regulated kinase (ERK)1/2 and the release of arachidonic acid along with prostaglandins E2 and I2. Signaling was desensitized without receptor internalization but rapidly resensitized upon succinate removal. Immunohistochemical evidence of phosphorylated ERK1/2 was found in cortical collecting duct cells of wild type but not SUCNR1 knockout streptozotocin-induced diabetic mice, indicating in vivo relevance. Since urinary succinate concentrations in health and disease are in the activation range of the SUCNR1, this receptor can sense succinate in the luminal fluid. Our study suggests that changes in the luminal succinate concentration may regulate several aspects of renal function

Evidence of a sudden increase in α-chloralose poisoning in dogs and cats in the Netherlands between 2018 and 2021

BACKGROUND: After changes in European Union biocide legislation, the Dutch Poisons Information Center observed a strong increase in information requests concerning dogs and cats exposed to α-chloralose. To investigate whether α-chloralose-based rodenticides are safe for non-professional use, additional information regarding poisoning scenarios and clinical course was collected. METHODS: Veterinarians reporting α-chloralose exposure over a 2.5-year period were contacted by mail for follow-up information concerning exposure scenario, product formulation, clinical course and treatment, and outcome. In total, information was collected for 96 dogs and 41 cats. RESULTS: Fifty-three of 96 dogs and 17 of 19 cats known to have been exposed to α-chloralose-based rodenticides developed signs of central nervous system (CNS) depression or sensory-induced CNS excitation. Mortality in dogs and cats following exposure was 1% and 18%, respectively. An additional 22 cats presented with clinical signs suggestive of α-chloralose poisoning, with a mortality of 5%. LIMITATIONS: Exposure to α-chloralose was not confirmed by biochemical analyses. CONCLUSION: Dogs and especially cats were at risk of poisoning from α-chloralose. If criteria such as acute toxicity and risk of (secondary) poisoning are applied during the approval of α-chloralose-based rodenticides, similar to anticoagulant-based rodenticides, it can be concluded that α-chloralose is also not safe for non-professional use

Genomic Investigation of Two Acinetobacter baumannii Outbreaks in a Veterinary Intensive Care Unit in The Netherlands

Acinetobacter baumannii is a nosocomial pathogen that frequently causes healthcare-acquired infections. The global spread of multidrug-resistant (MDR) strains with its ability to survive in the environment for extended periods imposes a pressing public health threat. Two MDR A. baumannii outbreaks occurred in 2012 and 2014 in a companion animal intensive care unit (caICU) in the Netherlands. Whole-genome sequencing (WGS) was performed on dog clinical isolates (n = 6), environmental isolates (n = 5), and human reference strains (n = 3) to investigate if the isolates of the two outbreaks were related. All clinical isolates shared identical resistance phenotypes displaying multidrug resistance. Multi-locus Sequence Typing (MLST) revealed that all clinical isolates belonged to sequence type ST2. The core genome MLST (cgMLST) results confirmed that the isolates of the two outbreaks were not related. Comparative genome analysis showed that the outbreak isolates contained different gene contents, including mobile genetic elements associated with antimicrobial resistance genes (ARGs). The time-measured phylogenetic reconstruction revealed that the outbreak isolates diverged approximately 30 years before 2014. Our study shows the importance of WGS analyses combined with molecular clock investigations to reduce transmission of MDR A. baumannii infections in companion animal clinics

A New Family of Lysozyme Inhibitors Contributing to Lysozyme Tolerance in Gram-Negative Bacteria

Lysozymes are ancient and important components of the innate immune system of animals that hydrolyze peptidoglycan, the major bacterial cell wall polymer. Bacteria engaging in commensal or pathogenic interactions with an animal host have evolved various strategies to evade this bactericidal enzyme, one recently proposed strategy being the production of lysozyme inhibitors. We here report the discovery of a novel family of bacterial lysozyme inhibitors with widespread homologs in gram-negative bacteria. First, a lysozyme inhibitor was isolated by affinity chromatography from a periplasmic extract of Salmonella Enteritidis, identified by mass spectrometry and correspondingly designated as PliC (periplasmic lysozyme inhibitor of c-type lysozyme). A pliC knock-out mutant no longer produced lysozyme inhibitory activity and showed increased lysozyme sensitivity in the presence of the outer membrane permeabilizing protein lactoferrin. PliC lacks similarity with the previously described Escherichia coli lysozyme inhibitor Ivy, but is related to a group of proteins with a common conserved COG3895 domain, some of them predicted to be lipoproteins. No function has yet been assigned to these proteins, although they are widely spread among the Proteobacteria. We demonstrate that at least two representatives of this group, MliC (membrane bound lysozyme inhibitor of c-type lysozyme) of E. coli and Pseudomonas aeruginosa, also possess lysozyme inhibitory activity and confer increased lysozyme tolerance upon expression in E. coli. Interestingly, mliC of Salmonella Typhi was picked up earlier in a screen for genes induced during residence in macrophages, and knockout of mliC was shown to reduce macrophage survival of S. Typhi. Based on these observations, we suggest that the COG3895 domain is a common feature of a novel and widespread family of bacterial lysozyme inhibitors in gram-negative bacteria that may function as colonization or virulence factors in bacteria interacting with an animal host

A case series of hypothermic, sedated cats with sensory-induced CNS excitation: alphachloralose poisoning?

Objective: In the autumn of 2018, the Board for the Authorisation of Plant Protection Products and Biocides (Ctgb) announced that the registration of rodenticides based on anticoagulants will not be renewed for use by a lay-person in the Netherlands. As a consequence the use of rodenticides based on alphachloralose is increasing rapidly. Case series: Between December 2018 and October 2020, the Dutch Poisons Information Center (DPIC) received 15 information requests concerning 21 predominantly hypothermic, sedated cats experiencing CNS excitation who were found outside. In four cases, multiple cats (2 or 3) from different households were found in the same neighborhood and presented at the veterinary clinic within a few hours of one another. Symptoms consisted predominantly of signs of CNS excitation, often sensory-induced i.e., ataxia (n ¼ 4), tremors/cramps (n¼ 17), seizures (n ¼ 3), and CNS depression i.e., drowsiness (n ¼ 3), lethargy/stupor (n ¼ 3) and coma (n ¼ 13). Sixteen cats were hypothermic with a median body temperature of 36.0 C (n ¼ 8) with a minimum of 32 C. Miosis during CNS depression was noted in eleven cats and mydriasis (n ¼ 3) during CNS excitation. Two cats appeared (temporarily) blind during their recovery. Other reported symptoms were respiratory distress (n ¼ 3) and bradycardia (n ¼ 3). Blood analysis was generally unremarkable. After activated charcoal was given (n¼ 3), intravenous fluid therapy (n ¼ 14) was started and the cats were observed in a warm, quiet environment. Additional treatment was necessary in 12 cats; diazepam (n ¼ 6), midazolam (n ¼ 4) and propofol constant rate infusion (n ¼ 2) were used. All cats except one, survived and fully recovered; twelve cats within 24 hours and seven cats in 48-72 hours. Length of recovery was unknown in one. Conclusion: Suspected alphachloralose poisoning is characterized by CNS depression combined with often sensory-induced CNS excitation. Small animals are at greater risk of developing hypothermia. Recognition of this typical clinical picture by veterinarians is important, because with proper treatment full recovery is possible. Whether these cats were poisoned by alphachloralose containing bait or indirectly by eating alphachoralose-sedated mice is unknown. However, the DPIC did receive one information request (left out of this case series) concerning a cat developing symptoms within 15 minutes after it was seen eating a alphachloralose sedated mouse

Succinate receptors in the kidney

Contains fulltext : 98375.pdf (publisher's version ) (Closed access)The G protein-coupled succinate and alpha-ketoglutarate receptors are closely related to the family of P2Y purinoreceptors. Although the alpha-ketoglutarate receptor is almost exclusively expressed in the kidney, its function is unknown. In contrast, the succinate receptor, SUCRN1, is expressed in a variety of tissues, including blood cells, adipose tissue, liver, retina, and the kidney. Recent evidence suggests SUCRN1 and its succinate ligand are novel detectors of local stress, including ischemia, hypoxia, toxicity, and hyperglycemia. Local levels of succinate in the kidney also activate the renin-angiotensin system and together with SUCRN1 may play a key role in the development of hypertension and the complications of diabetes mellitus, metabolic disease, and liver damage. This makes the succinate receptor a promising drug target to counteract an expanding number of interrelated disorders

"Curiosity killed the cat": cats poisoned by alphachloralose-containing rodenticides

Objective: In 2014 rodenticides based on alphachloralose were first introduced on the Dutch market. Alphachloralose (3.4-4.0%) is packaged in 10 g bags with pasta or coated grain and are licensed for private indoor use. Here we present a case-series of 18 cats exposed to alphachloralose-based rodenticides. Case series: During the night three, nine months old cats entered the garage after the door was left open accidentally. In the garage, the cats found an open box with twelve 10 g bags containing 4% alphachloralose paste. The next morning, the petowner found one cat lying dead in its urine and stool. The second cat displayed neurological signs while the third cat seemed healthy. Neurological signs consisted of generalized tremors and ataxia. After activated charcoal was given and intravenous fluid therapy was started, this cat was hospitalized for observation in a warm, quiet environment. After 24 hours, the cat was almost recovered and discharged. In addition to the abovementioned case history we have follow up information for another 15 cats. One cat remained asymptomatic after vomiting was induced. The estimated dose was 11 mg/Kg body weight. Fourteen cats with a median age of 0.4 years (range: 0.1-19; n ¼ 12) and median body weight of 2.8 Kg (range 0.5-4.0; n ¼ 14) developed signs and symptoms. It was possible to estimate the exposure dose in 8 cats; median dose 83 mg/Kg (range: 34-320). Symptoms consisted predominantly of signs of CNS excitation, often sensory-induced i.e., tremors/cramps (n ¼ 12) and seizures (n¼ 3), and CNS depression i.e., drowsiness (n ¼ 2), lethargy/stupor (n ¼ 2), coma (n ¼ 1) and ataxia (n¼ 6). Hypothermia was noted in six cats; the median body temperature was 35.3 C with a minimum of 32.0 C. Gastrointestinal symptoms were seen in three cats; two vomited spontaneously and the rodenticide was visible in the vomitus. Salivation was seen in another cat. In one cat, vomiting was induced followed by activated charcoal. Treatment of the CNS excitation signs was necessary in 6 cats, diazepam (n ¼ 3), midazolam (n ¼ 1) and midazolam followed by propofol constant rate infusion (n ¼ 2) was used. One, an 8- week-old kitten with a body weight of 0.6 Kg did not survive the poisoning. It was found hypothermic (32 C) and deeply sedated next to a ruptured bag of rodenticide and died one day later. Conclusion: In this case-series predominantly young cats (median age: 0.7 years; n ¼ 15) were exposed to alphachloralose containing rodenticides. Due to their small body weight, cats may develop a severe, potentially life-threatening poisonin

Role of decontamination in dogs poisoned by alphachloralose-based rodenticides: a case series

Objective: In 2014 rodenticides based on alphachloralose were first introduced onto the Dutch market. Alphachloralose (3.4-4.0%) is packaged in 10 g bags with paste or coated grain and is licensed for private indoor use. Here we present a case series of 95 dogs exposed to alphachloralose-containing rodenticides. The influence of decontamination measures on clinical course are evaluated. Case series: Decontamination by the veterinarian was performed in 64 dogs. In 45 dogs vomiting was induced and in 14 cases (ruptured) bags and in 27 cases coated grains/pasta were visible in the vomitus. Vomiting induction followed by activated charcoal was performed in 17 dogs resulting in 8 cases with (ruptured) bags and 4 with coated grains/pasta retrieved. Two dogs received only activated charcoal. Thirty-one of the decontaminated dogs with a median body weight of 8 Kg (range: 2.7-30.0) developed signs and symptoms (48%). The estimated median dose was 56.7 mg/Kg (range: 2.5-195.1; n ¼ 29). Mild symptoms (e.g., drowsiness) which resolved within 4 hours were seen in 9 dogs (29%). The remaining 22 dogs developed predominantly signs of CNS excitation (often sensory induced), i.e., tremors/cramps (n ¼ 8), and seizures (n ¼ 1), ataxia (n ¼ 12), and CNS depression e.g., drowsiness (n ¼ 7), stupor (n¼ 4), and coma (n ¼ 2). Hypothermia was noted in one dog. All symptoms resolved within 24 hours. No decontamination was performed in 31 dogs. Twenty-two of the 31 dogs with a median body weight of 6.5 Kg (range: 2.5-31.0, n ¼ 21) developed signs and symptoms (71%). The estimated median dose was 62.6 mg/Kg (range: 12.9-300.0; n ¼ 20), mild symptoms (e.g., drowsiness) which resolved within 4 hours were seen in 4 dogs (13%). The remaining 18 dogs developed predominantly signs of CNS excitation, often sensory induced (i.e., tremors/cramps (n ¼ 13), and seizures/status epilepticus (n ¼ 8), and CNS depression (i.e., drowsiness (n ¼ 5), stupor (n ¼ 2), coma (n ¼ 4) and ataxia (n ¼ 11). Hypothermia was noted in 6 dogs. Five dogs vomited spontaneously retrieving (partially) the ingested rodenticide in 4 cases. One 10-year-old dog (2.8 Kg) was euthanized. All other dogs survived the poisoning and all symptoms resolved within 60 hours. Conclusion: Decontamination measures such as induction of vomiting are effective in reducing exposure if they can be performed before signs develop, and thereby reduce the severity of alphachloralose-based rodenticide poisoning in dogs

The successful treatment of thallium sulfate toxicity in a dog using Prussian blue

Objective: Thallium sulfate, once commonly used as a household rodenticide, is a poisonous heavy metal banned in most countries due to its high toxicity. We report a case of thallium poisoning in a dog which was successfully treated using Prussian blue. Case report: An 8 Kg, 5-year-old female miniature schnauzer was presented to a veterinary clinic four days after eating corn soaked in an old liquid rodenticide containing 5 g/L thallium sulfate. The maximum estimated ingested dose was 1.25 grams thallium sulfate (156 mg/Kg). The reported minimal lethal dose of thallium sulfate in dogs is 12-15 mg/Kg [1]. The dog presented with signs of lethargy, anorexia, ataxia, abdominal pain and hair loss. Treatment of thallium toxicity is most effective using a specific chelator, Prussian blue. Availability of this antidote can be problematic, especially in a veterinary setting. In the Netherlands Prussian blue (Radiogardase-CSVR , ferric hexacyanoferrate(II)) is available via the National emergency stock of antidotes, this stock is not for veterinary use. Fortunately, the stock of Prussian blue was close to its expiration date however, and therefore it was made available for this dog. The dog received a human dose of 250 mg/Kg Prussian blue per day for 15 days. Additional treatments included butylscopolamine bromide (BuscopanVR) as an antispasmodic to treat the abdominal pain, dexamethasone to aid the Buscopan injections, lactulose as a laxative (Prussian blue can cause obstipation), and four days of activated charcoal following the Prussian blue treatment. Over the course of the poisoning the alopecia progressed, most markedly over the abdominal area and around the muzzle. Furthermore, dermal lesions appeared primarily situated at the soles of the paws. Behaviourally, the dog became more withdrawn and irritable. Blood thallium concentrations were determined 9, 18, and 38 days after exposure and were 196 mg/L, 20 mg/L, and 21.5 mg/L, respectively. After approximately six to eight weeks hair began to grow back and behaviour started to normalize. Three months after the exposure the dog was completely recovered, without any sequelae. Conclusion: To our knowledge this is the first documented case of a potentially severe thallium poisoning in a dog, successfully treated with Prussian blue. We propose that this treatment contributed significantly to the recovery of the dog. Our case demonstrates that, when available, Prussian blue can be safely administered to dogs to treat thallium toxicity