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Background After storing blood for a period of time, the structure and properties of the red blood cells (RBC) will change, which results in a decrease in the oxygen-carrying capacity, and further has a certain impact on their exosomes. Objectives Effective oxygen uptake (Q), P50, 2,3-DPG, and Na+-K+-ATP of RBC after different storage times were detected. Electron microscopy was used to observe the morphology of RBC and the characteristics of secreting exosomes. Western blot was used to detect the expression of phenotypes CD63 and CD81 of exosomes, and the expression of mitochondrial riboprotein MRPS35 of exosomes was also detected to explore the mechanism of decreased function of RBC with the extension of preservation time. Material and methods After the RBC suspension was prepared, the effective oxygen-carrying capacity (Q) and P50, as well as 2,3-DPG and Na+-K+-ATP were prepared. This was followed by morphology observation of erythrocyte exosomes using transmission electron microscope (TEM), and by western blot analysis of exosome phenotypes CD63 and CD81. Results Erythrocytes secrete exosomes, which results in abnormal expression of related proteins in mitochondria. This leads to increased ROS production, mitochondrial apoptosis and, finally, changes in or damage to erythrocytes. Conclusions Changes in the rheological properties and oxygen-carrying functions of erythrocytes during preservation are all observable manifestations, and underlying these manifestations are mechanisms of damage to erythrocytes at a molecular level. Erythrocytes secrete exosomes, which results in abnormal expression of related proteins in mitochondria, increasing ROS production, mitochondrial apoptosis and, finally, changes or damage to erythrocytes.

Background Red blood cell (RBC) transfusion is associated with systemic inflammation and immune suppression as adverse outcomes. Objectives To investigate the immunomodulatory function of the transfused autologous RBC in altering pro-inflammatory and immunosuppressive effects. Material and methods A total of 24 Sprague Dawley male rats were randomly divided into 3 groups (n = 8 in each group). Group 1 did not receive blood transfusions, while the other 2 groups of rats separately received transfusion of RBC stored for 14 days (group 2) and 35 days (group 3). The rats were treated with HO-1 inhibitor, HO-1 inducer and nuclear factor erythroid 2-related factor 2 (Nrf2) activator after they separately received autologous transfusion of RBC that were cryopreserved for 14 days or 35 days. The blood samples of the rats were collected 12 h after the transfusion, and the macrophage phenotype of M1 and M2 were analyzed with flow cytometry (FCM). Also, the surface protein expression of CD68 and CD200R in macrophages were analyzed and the inflammatory signals in the serum were measured with enzyme-linked immunosorbent assay (ELISA). Moreover, the location and expression of proteins heme oxygenase 1 (HO-1), arginine 1 (Arg-1) and nitric oxide synthase 2 (NOS2) in macrophage were detected with immunofluorescence (IF). Results Autologous transfusion of long-time stored ("old") RBC promoted macrophage polarization to M2 phenotype and upregulated the expression of its surface proteins CD68 and CD200R. The pro-inflammatory cytokines tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-1β, and IL-18 were inhibited, and the secretion of NOS isoforms (iNOS) in serum was reduced with blood transfusion; contrarily, the production of IL-10 and CCL22 was increased. Additionally, HO-1, Arg-1 and NOS2 proteins were located in the cytoplasm, and HO-1 and Arg-1 proteins were highly expressed in macrophage, while the expression of protein NOS2 was low. Moreover, Nrf2, HO-1 and Arg-1 proteins were upregulated in macrophage after receiving "old" RBC transfusion. Conclusions Autologous transfusion of "old" RBC drove the macrophage phenotype toward M2 macrophages and induced immunosuppressive effects through the IL-10-NRF2-HO-1 signals.

Transfusion of autologous blood is a timesaving, convenient, safe, and effective therapy from a clinical perspective, and often employed for the treatment of diabetic patients. Stabilization of HIF-1α has been widely reported to be a critical factor in the improvement of wound healing in diabetes. Therefore, our study reveals the roles of improved autologous blood in wound healing in diabetes, through autologous blood transfusion in a mouse model. Initially, BALB/c mice were subjected to streptozotocin for diabetic mouse model establishment. Diabetic mice were transfused with improved or standard autologous blood in perfusion culture system. Roles of improved autologous blood in mediating HIF-1α pathway were determined by measuring expression of VEGF, EGF, HIF-1α, and HSP-90. In order to assess the detailed regulatory mechanism of improved autologous blood in perspective of wound healing, cell proliferation, migration and cell cycle, fibroblasts isolated from diabetic mice were transfected with HIF-1α siRNA. Mice transfused with improved autologous blood exhibited increased levels of CD31 and α-SMA in skin tissues, and reduced TNF-α, IL-1β, and IL-6 levels, indicating that improved autologous blood promoted wound healing ability and reduced the release of inflammatory factors. Diabetic mice transfused with improved autologous blood presented activated HIF-1α pathway. The survival rate, proliferation, and migration of fibroblasts were elevated via activation of the HIF-1α pathway. Taken together, improved blood preservation solution could enhance the oxygen carrying capacity of red blood cells and wound healing in mice with diabetes, which is achieved through regulation of HIF-1α pathway.

Impaired wound healing is a debilitating complication of diabetes. The long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been recognized to be differentially expressed in various diseases. However, its underlying mechanism in diabetes has not been fully understood. Notably, we aim to examine the expression of MALAT1 in diabetic mice and its role in wound healing involving the hypoxia-inducible factor-1α (HIF-1α) signaling pathway with a modified autologous blood preservative solution reported. A mouse model of diabetes was established. MALAT1 was identified to promote the activation of the HIF-1α signaling pathway and to be enriched in autologous blood through modified preservation, which might facilitate the improvement of physiological function of blood cells. Through gain- or loss-of-function approaches, viability of fibroblasts cultured in high glucose, wound healing of mice, and collagen expression in wound areas were enhanced by MALAT1 and HIF-1α. Taken together, the present study demonstrated that the physiological status of mouse blood was effectively improved by modified autologous blood preservation, which exhibited upregulated MALAT1, thereby accelerating the fibroblast activation and wound healing in diabetic mice via the activation of the HIF-1α signaling pathway. The upregulation of MALAT1 activating the HIF-1α signaling pathway provides a novel insight into drug targets against diabetes., Graphical Abstract

Autotransfusion refers to a blood transfusion method in which the blood or blood components of the patient are collected under certain conditions, returned to himself when the patient needs surgery or emergency after a series of storing and processing. Although autotransfusion can avoid blood-borne diseases and adverse reactions related to allogeneic blood transfusion, a series of structural and functional changes of erythrocytes will occur during extension of storage time, thus affecting the efficacy of clinical blood transfusion. Our research was aimed to explore the change of erythrocyte oxygen-carrying capacity in different storage time, such as effective oxygen uptake (Q), P50, 2,3-DPG, Na+-K+-ATPase, to detect membrane potential, the change of Ca2+, and reactive oxygen species (ROS) change of erythrocytes. At the same time, Western blot was used to detect the expression of Mitofusin 1 (Mfn1) and Mitofusin 2 (Mfn2) proteins on the cytomembrane, from the perspective of oxidative stress to explore the function change of erythrocytes after different storage time. This study is expected to provide experimental data for further clarifying the functional status of erythrocytes with different preservation time in patients with autotransfusion, achieving accurate infusion of erythrocytes and improving the therapeutic effect of autologous blood transfusion, which has important clinical application value.

Erythrocyte membrane is crucial to maintain the stability of erythrocyte structure. The membrane protein on the surface of erythrocyte membrane enables erythrocyte to have plasticity and pass through the microcirculation without being blocked or destroyed. Decreased deformability of erythrocyte membrane protein will lead to a series of pathological and physiological changes such as tissue and organ ischemia and hypoxia. Therefore, this research collected 30 cases of healthy blood donors, and explored erythrocyte stored at different times relating indicators including effective oxygen uptake (Q), P50, 2,3-DPG, Na+-k+-ATP. Erythrocyte morphology was observed by electron microscopy. Western blot and immunofluorescence assay were used to detect membrane protein EPB41, S1P, GLTP, SPPL2A expression changes of erythrocyte. To explore the effective carry oxygen capacity of erythrocyte at different storage time resulting in the expression change of erythrocyte surface membrane protein.

Background: Blood is a fluid tissue composed of blood cells and plasma. It mainly transports oxygen, nutrients and metabolites for various tissues and organs of the body. Among them, red blood cells are the important means of oxygen transport. After the blood is stored for a period of time, the structure and properties of the red blood cells will change, which results in a decrease in the oxygen carrying capacity, and the change in the oxygen carrying capacity will also have a certain impact on their exosomes. Methods: Therefore, our research is to detect some carry oxygen function related indicators of red blood cells in different storage times, including effective oxygen uptake (Q), P50, 2, 3-DPG, Na+-K+-ATP. Electron microscopy was used to observe the morphology of red blood cells and the characteristics of secreting exosomes. Western Blot was used to detect the expression of phenotypes CD63 and CD81 of exosomes, and the expression of mitochondrial riboprotein MRPS35 of exosomes was also detected to explore the mechanism of decreased function of red blood cells with the extension of preservation time. Results: Changes in the rheological properties and oxygen-carrying functions of erythrocytes during the preservation process are all appearances, underlying which lies the damage mechanism at the molecular level of erythrocytes. Conclusion:Erythrocytes secrete exosomes, which resulted in abnormal expression of related proteins in mitochondria to increase ROS, mitochondrial apoptosis, and finally changes or damage to erythrocytes. Funding Statement: This work is supported by Key Disciplines Group Construction Project of Pudong Health Bureau of Shanghai (No.PWZxq2017-10), and National Natural Science Foundation of China (No. 81671919, 81870147). Declaration of Interests: All of the authors have no conflict of interest in this research. Ethics Approval Statement: Ethical approval was given by Gongli hospital, The Second Military Medical University.

When the active regeneration of a diesel particulate filter (DPF) occurs during a drop to idle (DTI) process, a massive amount of heat accumulates in the DPF, leading to a rather high peak temperature and a large temperature gradient, which can damage the DPF. Therefore, this study focuses on the temperature characteristics of a DPF in DTI active regeneration, so as to avoid the DPF damage at high temperature and large temperature gradient. The effects of particulate matter (PM) load, target regeneration temperature, and mass flow of exhaust gas on the temperature characteristics were investigated in this study. The peak temperature was found in the center of the outlet section of the DPF, the temperature gradient in the radial direction was much larger than that in the axial direction, and the maximum temperature gradient appeared near the outer surface of the DPF, that’s where the cracks are most likely to occur. In general, with the increase of PM load and target regeneration temperature, the peak temperature and the maximum temperature gradient of the DPF both increased, whereas they declined with the increase of mass flow of exhaust gas. Especially, decreasing PM load and increasing mass flow were very effective to decrease the maximum temperature gradient. Based on the experiments, two linear models were established to predict the peak temperature and the maximum temperature gradient of the DPF in DTI active regeneration respectively. Furthermore, the soot mass limit (SML) of the DPF was determined based on a series of DTI active regeneration experiments.

Background Impaired wound healing frequently occurs in diabetes mellitus (DM) and is implicated in impaired angiogenesis. Long non-coding RNA (lncRNA) H19 has been reported as being reduced in DM and played a critical role in inducing angiogenesis. Thus, we hypothesized that H19 may affect impaired wound healing in streptozotocin (STZ)-induced diabetic mice transfused with autologous blood preserved in standard preservative fluid or modified preservative fluid. Methods Fibroblasts in injured skin were isolated and cultured in vitro. After location of H19 in fibroblasts using fluorescence in situ hybridization (FISH), RNA-pull down, RNA immunoprecipitation (RIP), chromatin immunoprecipitation (ChIP), Co immunoprecipitation (COIP) and dual luciferase reporter gene assay were used to verify the binding of H19 to HIF-1α. Results The modified preservative fluid preserved autologous blood increased the H19 expression in fibroblasts, and maintained better oxygen-carrying and oxygen release capacities as well as coagulation function. Furthermore, H19 promoted HIF-1α histone H3K4me3 methylation and increased HIF-1α expression by recruiting EZH2. H19 promoted fibroblast activation by activating HIF-1α signaling pathway in fibroblasts and enhanced wound healing in diabetic mice. Conclusions Taken together, H19 accelerated fibroblast activation by recruiting EZH2-mediated histone methylation and modulating the HIF-1α signaling pathway, whereby augmenting the process of modified preservative fluid preserved autologous blood enhancing the postoperative wound healing in diabetic mice.