Alternatively Activated Macrophages in Types 1 and 2 Diabetes

Abstract

Macrophages are innate immune cells derived from monocytes, which, in turn, arise from myeloid precursor cells in the bone marrow. Macrophages have many important roles in the innate and adaptive immune response, as well as in tissue homeostasis. Two major populations have been defined: The classically activated macrophages that respond to intracellular pathogens by secreting proinflammatory cytokines and reactive oxygen species and alternatively activated macrophages which are induced during Th2 responses displaying anti-inflammatory activities. Both macrophage populations are central players in diabetes, the first one triggering inflammatory responses which initiates insulitis and pancreatic β cell death during type 1 diabetes, whereas the second population decreases hyperglycemia, insulitis, and inflammation in the pancreas, thereby negatively regulate type 1 diabetes. Obesity is an important factor in the development of type 2 diabetes; classically activated macrophages are a dominant cell population involved in the establishment of the inflammatory profile, insulin resistance, and activation of inflammatory signals during the development and progression of this disease. In contrast, alternatively activated macrophages regulate the release of proinflammatory cytokines, attenuating adipose tissue inflammation. Here, we review the advantages and disadvantages of these two macrophage populations with regard to their roles in types 1 and 2 diabetes.

Correlation between the decrease of cholesterol efflux from macrophages in patients with type II diabetes mellitus and down-regulated CYP7A1 expression

“…To date, the conclusions of studies on the expression and function of CYP7A1 in patients with type II DM and in associated animal models have been inconsistent (Shin and Osborne, 2008;Espinoza-Jiménez et al, 2012). The results of this study did not find abnormal CYP7A1 expression in the macrophages of patients with type II DM.…”

Mesenchymal stem cells promote CD206 expression and phagocytic activity of macrophages through IL-6 in systemic lupus erythematosus

“…Recent studies have demonstrated that the imbalance of macrophages plays an important role in autoimmune diseases [29][30][31][32][33]. In SLE, overactive M1 macrophages or macrophages induced by activated lymphocyte-derived DNA (ALD-DNA) contributed to the onset of lupus-like diseases in mice [34,35].…”

Glucocorticoid Treatment at Moderate Doses of SIVmac251-Infected Rhesus Macaques Decreases the Frequency of Circulating CD14+CD16++Monocytes But Does Not Alter the Tissue Virus Reservoir

“…4,11 CD16 + monocyte subsets are expanded in inflammatory and infectious conditions such as in neurological diseases, atherosclerosis, coronary heart disorders, cancer, and aging. 4,[12][13][14][15][16][17][18][19] Both the CD14 + + CD16 + and CD14 + CD16 + + monocyte subsets are expanded in the peripheral blood of HIV-infected subjects, suggesting that infection by HIV of this cellular compartment may contribute to the virus reservoir. [20][21][22] Remarkably, HIV-infected macrophage populations derived from CD16-positive monocytes, in contrast to those derived from CD16-negative monocytes, are better able to transfer the virus to resting CD4 + T cells in vitro.…”