Primordial GATA6 macrophages function as extravascular platelets in sterile injury.

Most multicellular organisms have a major body cavity that harbors immune cells. In primordial species such as purple sea urchins, these cells perform phagocytic functions but are also crucial in repairing injuries. In mammals, the peritoneal cavity contains large numbers of resident GATA6+ macrophages, which may function similarly. However, it is unclear how cavity macrophages suspended in the fluid phase (peritoneal fluid) identify and migrate toward injuries. In this study, we used intravital microscopy to show that cavity macrophages in fluid rapidly form thrombus-like structures in response to injury by means of primordial scavenger receptor cysteine-rich domains. Aggregates of cavity macrophages physically sealed injuries and promoted rapid repair of focal lesions. In iatrogenic surgical situations, these cavity macrophages formed extensive aggregates that promoted the growth of intra-abdominal scar tissue known as peritoneal adhesions.

Gastric antral vascular ectasia: a case report of a 10 year follow-up with special consideration of histopathological aspects.

The diagnosis of gastric antral vascular ectasia (GAVE) was made in a 67 year old patient with a ten year course of the disease, which was characterized by non-ulcerous dyspeptic symptoms in its early phase. The patient was treated successfully by antrectomy. The morphologic findings in the biopsy material ten to eight years before the operation corresponded with those of gastritis type C. The highly characteristic morphologic findings of sinusoidal capillary ectasia and multiple vascular thromboses appeared only in later biopsies taken during the work-up for iron deficiency anemia. The cause of the mucosal alterations was an acquired submucosal vascular anomaly (malformation).