The inflammation underlying both atherosclerosis and acute coronary syndromes is strongly related to monocyte-related actions. However, different monocyte subsets can play differential roles in the formation and destabilization of atherosclerotic plaque as well as healing of damaged myocardial tissue. Monocytes are currently being divided into three functionally distinct subsets with different levels of CD14 (cluster of differentiation 14) and CD16 expression. Thus, there are classical CD14++CD16-, intermediate CD14++CD16+ and nonclassical CD14+CD16++ monocytes. Here, we summarize the current knowledge on complex activities of different monocyte subsets in atherosclerosis and acute coronary syndromes. Moreover, we discuss which monocyte subsets can serve either as predictive biomarkers of cardiovascular risk or as potential targets used in atherosclerosis and its complications.
Three main monocyte subsets: classical CD14++CD16-, intermediate CD14++CD16+ and non-classical CD14+CD16++, differentially regulate tumor growth and survival. Thereby, in the present study we aimed to determine the role of distinct monocyte subsets in the prognostication of chronic lymphocytic leukemia (CLL). Moreover, we set out to analyze the effects of standard immune chemotherapy on different monocyte subsets and levels of membrane-associated and soluble forms of CD163, a monocyte/macrophage-related immunomodulatory protein. We demonstrated that the number of peripheral blood classical CD14++CD16- monocytes assessed at the time of diagnosis was negatively correlated with lymphocytosis and was decreased in the CLL patients who required immediate treatment as opposed to patients who qualified to 'watch and wait' strategy. Notably, lower baseline levels of classical CD14++CD16- monocytes in CLL patients who were qualified for 'watch and wait' therapy were associated with shorter time to initial treatment. Notably, therapy with rituximab, cyclophosphamide and fludarabine resulted in a significant reduction in the number of non-classical CD14+CD16++ monocytes and soluble form of CD163 but upregulation of membrane-associated monocyte CD163. Our data indicate that distinct monocyte subsets and two forms of CD163 are differentially modulated by both CLL and immune chemotherapy. Moreover, we proposed that quantification of classical monocytes at the time of diagnosis contributes to better prognostication of CLL patients.
Muscular dystrophies (MD) are heterogeneous group of diseases characterized by progressive muscle dysfunction. There is a large body of evidence indicating that angiogenesis is impaired in muscles of MD patients. Therefore, induction of dystrophic muscle revascularization should become a novel approach aimed at diminishing the extent of myocyte damage. Recently, we and others demonstrated that administration of granulocyte colony-stimulating factor (G-CSF) resulted in clinical improvement of patients with neuromuscular disorders. To date, however, the exact mechanisms underlying these beneficial effects of G-CSF have not been fully understood. Here we used flow cytometry to quantitate numbers of CD34+ cells, endothelial progenitor cells, and different monocyte subsets in peripheral blood of pediatric MD patients treated with repetitive courses of G-CSF administration. We showed that repetitive cycles of G-CSF administration induced efficient mobilization of above-mentioned cells including cells with proangiogenic potential. These findings contribute to better understanding the beneficial clinical effects of G-CSF in pediatric MD patients.
Background: Previously, we demonstrated that glucocorticoid (GC) treatment of asthmatic patients resulted in decreasing frequencies of monocyte subsets expressing CD16 and capable of releasing TNF-α. Here, we wished to analyze whether the active form of vitamin D, i.e. vitamin D3, referred to as 1α,25-dihydroxyvitamin D3 [1,25-(OH)2D3] can exert GC-like proapoptotic effects on CD16-positive monocytes and thus decrease the proinflammatory potential of these cells. Finally, we set out to investigate whether the addition of 1,25-(OH)2D3 would facilitate the use of lower doses of GC without decreasing their anti-inflammatory properties. Methods: Peripheral blood mononuclear cells collected from healthy individuals and asthmatic patients were cultured with 1,25-(OH)2D3 and/or varying doses of GC in the presence or absence of caspase inhibition. The cells were either directly stained for extracellular markers or prestimulated with lipopolysaccharide for the assessment of intracellular cytokine production and then analyzed by flow cytometry. Results: We found that 1,25-(OH)2D3 alone (and in combination with GC) decreased the frequency of CD14++CD16+ and CD14+CD16++ monocytes from asthmatic patients and significantly diminished TNF-α production by the monocytes. With regard to the CD14+CD16++ subset, the monocyte-depleting effects of 1,25-(OH)2D3 were abrogated in the presence of pan-caspase inhibitor, suggesting a proapoptotic mechanism of 1,25-(OH)2D3 action. Interestingly, we found that a combined treatment of 1,25-(OH)2D3 and GC allowed for a 5-fold reduction of the GC dose while maintaining their anti-inflammatory effects. Conclusions: This study has revealed novel immunomodulatory properties of 1,25-(OH)2D3 directed against monocyte subsets capable of TNF-α production. In addition, our data suggest that the introduction of 1,25-(OH)2D3 to anti-inflammatory therapy would possibly allow for the use of lower doses of GC.
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