Pericytes modulate endothelial inflammatory response during bacterial infection.

Pericytes are located around blood vessels, in close contact with endothelial cells. We discovered that pericytes dampen pro-inflammatory endothelial cell responses. Endothelial cells co-cultured with pericytes had markedly reduced expression of adhesion molecules (PECAM-1 and ICAM-1) and proinflammatory cytokines (CCL-2 and IL-6) in response to bacterial stimuli (Brucella ovis, Listeria monocytogenes, or Escherichia coli lipopolysaccharide). Pericyte-depleted mice intraperitoneally inoculated with either B. ovis, a stealthy pathogen that does not trigger detectable inflammation, or Listeria monocytogenes, developed peritonitis. Further, during Citrobacter rodentium infection, pericyte-depleted mice developed severe intestinal inflammation, which was not evident in control mice. The anti-inflammatory effect of pericytes required connexin 43, as either chemical inhibition or silencing of connexin 43 abrogated pericyte-mediated suppression of endothelial inflammatory responses. Our results define a mechanism by which pericytes modulate inflammation during infection, which shifts our understanding of pericyte biology: from a structural cell to a pro-active player in modulating inflammation. IMPORTANCE: A previously unknown mechanism by which pericytes modulate inflammation was discovered. The absence of pericytes or blocking interaction between pericytes and endothelium through connexin 43 results in stronger inflammation, which shifts our understanding of pericyte biology, from a structural cell to a player in controlling inflammation.

Diffuse thoracic and peritoneal papillary mesothelioma in an adult cow: case report

Mesothelioma is a rare tumor of mesothelium and usually spread by implantation in the same cavity it arises. Regarding bovine mesotheliomas, the abdominal cavity is the most affected site. This article describes a case of diffuse papillary mesothelioma within both thoracic and abdominal cavity with nodal metastasis in an adult cow based on cytology, histopathology, and immunohistochemical analysis. A 7-years-old cow, Nelore breed (Brazilian beef cattle), with clinical signs of tachypnea, abdominal distention, and positive jugular venous pulse was slaughtered and necropsied due to persistent weight loss. The main gross findings were several verrucous and yellowish nodules spread on pericardium, pleura, and peritoneum. Mediastinal lymph nodes were enlarged and hemorrhagic with multiples yellowish spots on cut surface. The diagnoses of diffuse mesothelioma with nodal metastasis was established and ratified by the microscopic analysis. Immunohistochemical results had strong positivity for cytokeratin and the Ki-67 showed proliferative index of 28%. Vimentin was positive only in the cells of fibrous tissue. In this case, the initial site of the mesothelioma was not recognized. Although it is a post-mortem study, cytology may be very helpful in vivo investigation. Equally important, is the IHC to better comprehend this tumor and its behavior.(AU)

Diffuse thoracic and peritoneal papillary mesothelioma in an adult cow: case report

Mesothelioma is a rare tumor of mesothelium and usually spread by implantation in the same cavity it arises. Regarding bovine mesotheliomas, the abdominal cavity is the most affected site. This article describes a case of diffuse papillary mesothelioma within both thoracic and abdominal cavity with nodal metastasis in an adult cow – based on cytology, histopathology, and immunohistochemical analysis. A 7-years-old cow, Nelore breed (Brazilian beef cattle), with clinical signs of tachypnea, abdominal distention, and positive jugular venous pulse was slaughtered and necropsied due to persistent weight loss. The main gross findings were several verrucous and yellowish nodules spread on pericardium, pleura, and peritoneum. Mediastinal lymph nodes were enlarged and hemorrhagic with multiples yellowish spots on cut surface. The diagnoses of diffuse mesothelioma with nodal metastasis was established and ratified by the microscopic analysis. Immunohistochemical results had strong positivity for cytokeratin and the Ki-67 showed proliferative index of 28%. Vimentin was positive only in the cells of fibrous tissue. In this case, the initial site of the mesothelioma was not recognized. Although it is a post-mortem study, cytology may be very helpful in vivo investigation. Equally important, is the IHC to better comprehend this tumor and its behavior.