Surface morphology of the central macrophages of erythroblastic islets in the spleen of aged and pregnant mice: an immunohistochemical light microscopic study

Abstract

Summary. This study used 100-m thick paraffin sections stained by the ER-HR3 antibody to examine the three-dimensional surface morphology of the central macrophages of erythroblastic islets in the splenic red pulp of aged and pregnant mice. The ER-HR3-positive cells were the macrophages located at the center of the erythroblastic islets, and the number per unit of splenic area was almost constant until 30 days of age, thereafter showing a marked decrease. In pregnant females, the ER-HR3-positive macrophage number significantly increased and became approximately eight times higher than the control value. In aged virgin females, the islet macrophages were generally ovoid in cell profile, and shallow cup-shaped dents were formed on their cell surface. However, in pregnant females, the macrophages became larger in size, and cell socket structures, formed by long finger-like cytoplasmic processes, became prominent on their cell surface. The 3-D images, obtained from 100-m thick paraffin sections, provided the clear morphological evidence of the activity of the islet macrophages in spleen erythropoiesis.

Mobilization with granulocyte colony-stimulating factor blocks medullar erythropoiesis by depleting F4/80+VCAM1+CD169+ER-HR3+Ly6G+ erythroid island macrophages in the mouse

“…15 [5,27,28], also identifies erythroid island macrophages in the BM. However, the exact identity of this antigen and whether its expression is necessary to support erythropoiesis remain unknown [44].…”

“…After synthesizing large quantities of hemoglobin, the final stages of erythroblast maturation involves extrusion of the nucleus to form anuclear reticulocytes, which then change shape in the blood to fully matured erythrocytes. Microscopy sections of BM have revealed that maturing erythroblasts rosette around a central macrophage to form erythroid islands [1][2][3][4][5]. It has been proposed that these erythroid island macrophages contribute to the efficient transport of iron to erythroblasts [2,6] enabling the synthesis of large quantities of hemoglobin as O 2 and CO 2 transport which depends on Fe 2+ complexed in the heme molecule.…”

Extramedullary hematopoiesis: Elucidating the function of the hematopoietic stem cell niche (Review)

“…Erythroblastic islands of bone marrow constitute the basic structure required for erythropoiesis, and include central macrophages that form the microenvironment required for erythroblast development and enucleation, as well as phagocytosis of extruded nuclei (40,41). Following the release of HSCs from bone marrow niches, erythroid cell maturation is facilitated and the resulting erythroid colony-stimulating units may adhere to the central macrophages forming distinct erythroblastic islands that are separate from the existing niches (41).…”

“…Following the release of HSCs from bone marrow niches, erythroid cell maturation is facilitated and the resulting erythroid colony-stimulating units may adhere to the central macrophages forming distinct erythroblastic islands that are separate from the existing niches (41). This hypothesis was found to be applicable to EMH-positive spleens, where CXCL12-positive signals on endothelial cells were identified distant from clusters of mature erythroblasts (21).…”

Expression of Tiam1 in Lung Cancer and its Clinical Significance

“…Cellular rigidity also declines significantly, cell migration and athletic ability increase, and protuberance and pseudopodium are present in the cell membrane, thus increasing cell invasiveness (Sonoda and Sasaki, 2008;Ferrandina et al, 2009). In the present study, Tiam1 expression in the normal lung tissues and lung cancer tissue was examined by immunohistochemistry to analyze the relationship between Tiam1 expression and metastasis of lung cancer to provide new therapeutic targets for the clinical treatment of cancer.…”