PhD student Dessi Loukov in the lab of Dr. Dawn Bowdish, recently published a study showing that splenomegaly in old mice is a result of extramedullary hematopoiesis, and that this increased monopoiesis is driven by age-associated increase in TNF. The study compared changes in the microarchitecture and composition of the spleen in old and young mice and found that in old mice, there was an increase in the size and cellularity of the red pulp (the site of hematopoiesis of myeloid precursors). To study the role of TNF in the development of extramedullary hematopoiesis, they used TNF KO mice and found that these mice did not have increased extramedullary monopoiesis. Furthermore, they demonstrated that increased splenic myelopoiesis was a result of the aging microenvironment. This work suggests that strategies which aim to decrease the inflammatory microenvironment that comes with aging, would be effective in reducing inflammatory diseases propagated by cells of the myeloid lineage. Read More