Angiotensin II Alters Mitochondrial Membrane Potential and Lipid Metabolism in Rat Colonic Epithelial Cells.

An over-active renin-angiotensin system (RAS) is characterized by elevated angiotensin II (Ang II). While Ang II can promote metabolic and mitochondrial dysfunction in tissues, little is known about its role in the gastrointestinal system (GI). Here, we treated rat primary colonic epithelial cells with Ang II (1-5000 nM) to better define their role in the GI. We hypothesized that Ang II would negatively affect mitochondrial bioenergetics as these organelles express Ang II receptors. Ang II increased cellular ATP production but reduced the mitochondrial membrane potential (MMP) of colonocytes. However, cells maintained mitochondrial oxidative phosphorylation and glycolysis with treatment, reflecting metabolic compensation with impaired MMP. To determine whether lipid dysregulation was evident, untargeted lipidomics were conducted. A total of 1949 lipids were detected in colonocytes spanning 55 distinct (sub)classes. Ang II (1 nM) altered the abundance of some sphingosines [So(d16:1)], ceramides [Cer-AP(t18:0/24:0)], and phosphatidylcholines [OxPC(16:0_20:5(2O)], while 100 nM Ang II altered some triglycerides and phosphatidylserines [PS(19:0_22:1). Ang II did not alter the relative expression of several enzymes in lipid metabolism; however, the expression of pyruvate dehydrogenase kinase 2 (PDK2) was increased, and PDK2 can be protective against dyslipidemia. This study is the first to investigate the role of Ang II in colonic epithelial cell metabolism.

Association between total hypercalcaemia and iliosacral lymph node metastasis in dogs diagnosed with anal sac adenocarcinoma using abdominal ultrasonography.

BACKGROUND: Anal sac adenocarcinoma (ASACA) in dogs is a malignant perianal tumour that often metastasizes to the iliosacral lymph nodes. Additionally, this tumour can be associated with hypercalcemia of malignancy. To date, no study has looked at the association between increased blood calcium levels and suspected or confirmed lymph node metastasis as a primary objective. OBJECTIVE: The objective of this study was to determine if increased total serum calcium level is associated with iliosacral lymph node metastasis in dogs diagnosed with ASACA. METHODS: Medical records of a single referral hospital were searched to identify dogs examined between 2011 and 2021 that had a diagnosis of ASACA via cytology or histopathology. Only dogs that had serum total calcium recorded and abdominal ultrasound were included in the study. All images were reviewed by a board-certified radiologist blinded to any patient identifiers. RESULTS: Of the 58 dogs, 33% (19/58) had total hypercalcaemia, and of these, 68% had confirmed or suspected iliosacral lymph node metastasis. Total hypercalcaemia was significantly associated with confirmed or suspected iliosacral lymph node metastasis (p < 0.01). However, 46% (11/24) of dogs with confirmed or suspected iliosacral lymph node metastasis were normocalcaemic. CONCLUSIONS: Based on these results, it is suggested that while the presence of total hypercalcaemia may increase the likelihood of concurrent lymph node metastasis, total hypercalcaemia alone cannot be used as a screening tool for lymph node metastasis. Dogs diagnosed with ASACA should undergo full staging regardless of total serum calcium values.

Risk factors for intraoperative hemorrhage and perioperative complications and short- and long-term outcomes during surgical patent ductus arteriosus ligation in 417 dogs.

OBJECTIVE: To evaluate the short- and long-term outcomes of dogs undergoing surgical ligation for a left-to-right shunting patent ductus arteriosus (PDA), identify risk factors for intraoperative hemorrhage and intra- and postoperative complications, and report overall mortality rates. ANIMALS: 417 client-owned dogs undergoing surgical ligation for a left-to-right shunting PDA between January 2010 and January 2020. PROCEDURES: Data recorded included patient signalment, echocardiogram findings, intraoperative complications and mortality, postoperative complications, and short- and long-term outcomes. RESULTS: There was no association between age and risk of intraoperative hemorrhage (P = .7), weight and intraoperative hemorrhage (P = .96), or increasing left atrium-to-aortic (LA:Ao) ratio and intraoperative hemorrhage (P = .08). Intraoperative hemorrhage occurred in 10.8% of patients. Intraoperative mortality was 2%. Ninety-five percent of dogs experiencing intraoperative hemorrhage survived to discharge. Survival to discharge was 97%. One- and 5-year survival rates were 96.4% and 87%, respectively. CLINICAL RELEVANCE: Surgical ligation for a left-to-right shunting PDA is recommended due to the good long-term prognosis. Certain preoperative factors such as age, weight, and the presence and degree of mitral valve regurgitation had no detectable association with risks of intraoperative hemorrhage and, therefore, should not preclude surgical treatment for a left-to-right shunting PDA. Future studies are needed to further assess the association between increasing LA:Ao ratio and risk of intraoperative hemorrhage.

Laparoscopic or laparoscopic-assisted cystopexy for pelvic bladder in 3 dogs.

The techniques and clinical outcomes of laparoscopic or laparoscopic-assisted cystopexy in 3 dogs diagnosed with pelvic bladder are reported herein. The medical records of 2 dogs with pelvic bladder which underwent laparoscopic cystopexy, and 1 dog which underwent laparoscopic-assisted cystopexy were reviewed. Data retrieved included signalment, clinical signs, diagnostic imaging, surgical technique, and clinical outcome. Long-term follow-up was obtained by verbal interviews with owners. Laparoscopic or laparoscopic-assisted cystopexy was successfully performed to reposition the urinary bladder within the abdominal cavity in all dogs. An intracorporeal suture technique was used in 2 dogs, whereas an extracorpreal technique was used in 1 dog. Two dogs with stranguria experienced complete resolution immediately following surgery and remained disease-free at 18 mo after cystopexy. A third dog with urinary incontinence subjectively improved (according to the owner) but had not resolved completely 2 d following surgery. Key clinical message: Laparoscopic or laparoscopic-assisted cystopexy may be an effective treatment for pelvic bladder in dogs and may offer a minimally invasive alternative to laparotomy. Male dogs with stranguria as the primary clinical sign may experience complete resolution following cystopexy.

Cystopexie laparoscopique ou assistée par laparoscopie pour une vessie pelvienne chez trois c hiens. Les techniques et les résultats cliniques de la cystopexie laparoscopique ou assistée par laparoscopie chez trois chiens diagnostiqués avec une vessie pelvienne sont rapportés ici.Les dossiers médicaux de deux chiens ayant une vessie pelvienne ayant subi une cystopexie laparoscopique et d'un chien ayant subi une cystopexie assistée par laparoscopie ont été examinés. Les données récupérées comprenaient le signalement, les signes cliniques, l'imagerie diagnostique, la technique chirurgicale et les résultats cliniques. Le suivi à long terme a été obtenu par des entrevues verbales avec les propriétaires.La cystopexie laparoscopique ou assistée par laparoscopie a été réalisée avec succès pour repositionner la vessie dans la cavité abdominale chez tous les chiens. Une technique de suture intracorporelle a été utilisée chez deux chiens, tandis qu'une technique extracorporelle a été utilisée chez un chien. Deux chiens atteints de strangurie ont connu une résolution complète immédiatement après la chirurgie et sont restés sans maladie à 18 mois après la cystopexie. Un troisième chien souffrant d'incontinence urinaire s'est amélioré subjectivement (selon le propriétaire) mais celle-ci n'a pas complètement disparu 2 jours après la chirurgie.Message clinique clé :La cystopexie laparoscopique ou assistée par laparoscopie peut être un traitement efficace pour une vessie pelvienne chez le chien et peut offrir une alternative peu invasive à la laparotomie. Les chiens mâles atteints de strangurie comme signe clinique principal peuvent connaître une résolution complète après la cystopexie.(Traduit par Dr Serge Messier).

Distribution of histopathologic types of primary pulmonary neoplasia in dogs and outcome of affected dogs: 340 cases (2010-2019).

OBJECTIVE: To provide updated information on the distribution of histopathologic types of primary pulmonary neoplasia in dogs and evaluate the effect of postoperative adjuvant chemotherapy in dogs with pulmonary carcinoma. ANIMALS: 340 dogs. PROCEDURES: Medical records of dogs that underwent lung lobectomy for removal of a primary pulmonary mass were reviewed, and histopathologic type of lesions was determined. The canine lung carcinoma stage classification system was used to determine clinical stage for dogs with pulmonary carcinoma. RESULTS: Pulmonary carcinoma was the most frequently encountered tumor type (296/340 [87.1%]), followed by sarcoma (26 [7.6%]), adenoma (11 [3.2%]), and pulmonary neuroendocrine tumor (5 [1.5%]); there was also 1 plasmacytoma and 1 carcinosarcoma. Twenty (5.9%) sarcomas were classified as primary pulmonary histiocytic sarcoma. There was a significant difference in median survival time between dogs with pulmonary carcinomas (399 days), dogs with histiocytic sarcomas (300 days), and dogs with neuroendocrine tumors (498 days). When dogs with pulmonary carcinomas were grouped on the basis of clinical stage, there were no significant differences in median survival time between dogs that did and did not receive adjuvant chemotherapy. CLINICAL RELEVANCE: Results indicated that pulmonary carcinoma is the most common cause of primary pulmonary neoplasia in dogs; however, nonepithelial tumors can occur. Survival times were significantly different between dogs with pulmonary carcinoma, histiocytic sarcoma, and neuroendocrine tumor, emphasizing the importance of recognizing the relative incidence of these various histologic diagnoses. The therapeutic effect of adjuvant chemotherapy in dogs with pulmonary carcinoma remains unclear and warrants further investigation.

Disease network data for the pesticide fipronil in rat dopamine cells.

Transcriptome data were collected in rat dopamine cells exposed to fipronil for 24 h using microarray analysis. Fipronil is a phenylpyrazole pesticide that acts to inhibit gamma-aminobutyric acid (GABA), blocking inhibitory synaptic transmission in the central nervous system. Transcriptome data were subjected to pathway analysis and subnetwork enrichment analysis. We report that 25 µM fipronil altered transcriptional networks in dopamine-synthesizing cells that are associated with Alzheimer's Disease, Huntington Disease, and Schizophrenia. Data analysis revealed that nerve fibre degeneration, nervous system malformations, neurofibrillary tangles, and neuroinflammation were all disease processes related to the transcriptome profile observed in the rat neuronal cells. Other disease networks altered by fipronil exposure at the transcript level were associated with the mitochondria, including mitochondrial DNA depletion syndrome and mitochondrial encephalomyopathies. These data, along with those presented in Souders et al. (2021), are significant because they increase understanding into the molecular mechanisms underlying human disease following exposures to neuroactive pesticides. These data can be reused to inform adverse outcome pathways for neurotoxic pesticides.

Mitochondrial and transcriptome responses in rat dopaminergic neuronal cells following exposure to the insecticide fipronil.

The phenylpyrazole fipronil is an insecticide that inhibits γ -amino-butyric acid (GABA) ionotropic receptors in the central nervous system. Experimental evidence suggests that fipronil acts as a neurotoxin and it is implicated in neurodegenerative diseases; however, the mechanisms of neurotoxicity are not fully elucidated. The objective of this study was to quantify mechanisms of fipronil-induced neurotoxicity in dopamine cells. Rat primary immortalized mesencephalic dopaminergic cells (N27) were treated with fipronil (0.25 up to 500 µM depending on the assay). We measured endpoints related to mitochondrial bioenergetics, mitophagy, mitochondrial membrane potential, and ATP production in addition to discerning transcriptome responses to the pesticide. Fipronil reduced cell viability at 500 µM after 24 h exposure and caspase 3/7 activity was significant increased after 6 and 12 h by 250 and 500 µM fipronil. Subsequent endpoints were thus assessed at concentrations that were below cytotoxicity. We measured oxidative respiration of N27 cells following a 24 h exposure to one dose of either 0.25, 2.5, 25, or 50 µM fipronil. Oxygen consumption rates (OCR) were not different between vehicle-control and 0.25 or 2.5 µM fipronil treatments, but there was a ∼40-60 % reduction in basal respiration, as well as reduced oligomycin-induced ATP production at 50 µM. The reduction in OCR is hypothesized to be related to lower mitochondrial mass due to mitophagy. Mitochondrial membrane potential was also sensitive to fipronil, and it was compromised at concentrations of 2.5 µM and above. To further elucidate the mechanisms linked to neurotoxicity, we conducted transcriptomics in dopamine cells following treatment with 25 µM fipronil. Fipronil suppressed transcriptional networks associated with mitochondria (damage, depolarization, permeability, and fission), consistent with its effects on mitochondrial membrane potential. Altered gene networks also included those related to Alzheimer disease, inflammatory disease, nerve fiber degeneration, and neurofibrillary tangles. This study clarifies molecular targets of fipronil-induced neurotoxicity and supports, through multiple lines of evidence, that fipronil acts as a mitochondrial toxicant in dopamine cells. This is relevant to neurodegenerative diseases like Parkinson's disease as exposure to fipronil is associated with the progressive loss of nigrostriatal dopaminergic neurons in rodents.