Vitamin A status and its hematological correlates among preschool children in Beijing, China.

BACKGROUND AND OBJECTIVES: Vitamin A is vital for the growth and health of children. This study aimed to estimate the current vitamin A status and the prevalence of vitamin A deficiency (VAD) among preschool children and explore the correlation between serum vitamin A concentration and changes in hematological parameters. METHODS AND STUDY DESIGN: The study included 697 children aged 1-6 years, presenting for routine checkups at the Department of Pediatrics, Peking University Shougang Hospital, Beijing, from April 2017 to December 2020. We obtained the complete laboratory test data of 630 children. RESULTS: The mean serum vitamin A concentration among preschool children was 0.29±0.08 mg/L, with a median of 0.29 mg/L. The proportion of children with VAD and marginal VAD (MVAD) was 9.84% and 43.49%, respectively. The highest prevalence of VAD and MVAD was in the 3- to 4-year age group. Compared with the normal vitamin A serum concentration group, other groups had lower mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and higher red blood cell distribution width. The mean serum vitamin A concentration among anemic children was significantly lower (0.27±0.07 mg/L) than among those children who were not anemic (p<0.05). CONCLUSIONS: VAD constitutes a public health problem in northern China. The prevalence of VAD is highest, and the serum vitamin A concentration was the lowest among preschool children aged 3-4 years. Vitamin A serum concentration was associated with red blood cell indices. We should attach more importance to those children aged 3-4 years.

Oxidized low-density lipoprotein-induced microparticles promote endothelial monocyte adhesion via intercellular adhesion molecule 1.

Oxidized low-density lipoprotein (oxLDL) accumulates early in atherosclerotic lesions and plays an important role in the progressive formation of atherosclerotic plaques. Endothelial derived microparticles (EMPs) form a heterogeneous population of <1-µm particles that shed from endothelial membranes upon activation. While EMPs are shown to be involved in atherosclerotic pathophysiology and progression, there is no report regarding the relationship between oxLDL and EMPs. In this study, we aim to determine the influence of oxLDL on endothelial microparticle release and the subsequent regulation of the endothelial activation. EMPs were collected from the medium of human umbilical vein endothelial cells (HUVECs) treated with oxLDL or PBS as control. We find that oxLDL increases the release of EMPs containing intercellular adhesion molecule 1 (ICAM-1) but not vascular cell adhesion molecule 1 (VCAM-1). Confocal microscopy analysis further demonstrates that these EMPs interact with endothelial cells and increase the expression of ICAM-1 in HUVECs. The fact that injecting oxLDL-induced EMPs via the tail vein of ICR mice augments ICAM-1 expression on aortic endothelial cells confirms our results in vivo. Finally, oxLDL-induced EMPs from HUVECs increase the adhesion of monocytes to endothelial cells as determined by the adhesion assay. Our study suggests that oxLDL may augment the release of EMPs harboring increased levels of ICAM-1 that can be transferred to endothelial cells elsewhere. This leads to increased monocyte recruitment in other regions where oxLDL accumulation was initially more limited. EMPs may therefore serve as the mediator that propagates oxLDL-induced endothelial inflammation.