Ruptured erythrocytes inhibit the oxidation of membranes by 15-hydroperoxy-eicosatetraenoic acid

Integrated Network Pharmacology and Metabolomics Analysis to Reveal the Potential Mechanism of Siwu Paste on Aplastic Anemia Induced by Chemotherapy Drugs

Purpose

This study aimed to reveal the multicomponent synergy mechanisms of SWP based on network pharmacology and metabolomics for exploring the relationships of active ingredients, biological targets, and crucial metabolic pathways.

Materials

Network pharmacology, including TRRUST, GO, and KEGG, enrichment was used to discover the active ingredients and potential regulation mechanisms of SWP. LC-MS and multivariate data analysis method were further applied to analyze serum metabolomics profiling for discovering the potential metabolic mechanisms of SWP on AA induced by Cyclophosphamide (CTX) and 1-Acetyl-2-phenylhydrazine (APH).

Results

A total of 27 important bioactive ingredients meeting the ADME (absorption, distribution, metabolism, and excretion) screening criteria from SWP were selected. Interaction networks were constructed and validated based on the 10 associated ingredients with the relevant targets. A total of 125 biomarkers were found by Metabolomics approach, which associated with the development of AA, mainly involved in amino acid metabolism and lipid metabolism. While SWP can reverse the above 12 metabolites changed by AA. Network analysis revealed the synergistic effects of SWP through the 43 crucial pathways, including Sphingolipid signaling pathway, Sphingolipid metabolism, Arginine and proline metabolism, VEGF signaling pathway, Estrogen signaling pathway.

Conclusion

The study suggested that SWP is a useful alternative for the treatment of AA induced by CTX + APH. Its potential mechanisms are to improve hematopoietic microenvironment and promote bone marrow hematopoiesis therapies.

Human erythrocytes are protected against chromate-induced peroxidation

In previous studies performed in this laboratory it was realized that in a broad concentration range (0.5-8 mM) dichromate does not induced red blood cell (RBC) peroxidation. To investigate the reasons behind RBC protection against chromate-induced peroxidation, the effects of 8 mM dichromate on white ghost and RBC peroxidation, RBC antioxidant system and hemoglobin status, as well as RBC osmotic fragility and morphology, were studied in more detail. It was observed that the peroxidation level induced by dichromate on RBCs is practically negligible when compared with the peroxidation induced in white ghosts. Furthermore, the osmotic fragility of RBCs exposed to dichromate is not altered, but the cells undergo echinocytic transformation, probably due to chromate-induced structural RBC membrane modifications. The activities of catalase, gluthatione peroxidase, and superoxide dismutase of RBCs exposed to dichromate were similar to those observed in controls, but the gluthatione reductase and GSH levels were significantly reduced (P<0. 05). Concomitantly, GSSG and methemoglobin levels increased and NADH-methemoglobin reductase activity decreased. These results indicate that chromate does not induce RBC peroxidation, but does promote echinocytic shape transformation, oxidation of hemoglobin and GSH, and inhibition of gluthatione reductase and methemoglobin reductase. The enzymatic antioxidant defense system and hemoglobin oxidation are probably involved in the mechanism of RBC proctection against chromate-induced peroxidation, as is discussed.

Effect of donor age on the susceptibility of erythrocytes and erythrocyte membranes to cumene hydroperoxide-induced oxidative stress

A comparative study on erythrocytes and erythrocyte membranes of healthy elderly and young adults was carried out to understand how the antioxidant defense capacity is effected by aging. The levels of endogenous malondialdehyde and Ca(2+)-ATPase activity were taken as indices of oxidative damage. In addition, chemiluminescence measurements were performed on intact erythrocytes. The susceptibility of these parameters to in vitro cumene hydroperoxide, under low oxidant level that does not induce hemolysis, was also taken as an age-related indicator of the endogenous peroxidative potential of the erythrocytes. Our data showed that the content of malondialdehyde and Ca(2+)-ATPase activity did not change with age. Furthermore, the susceptibility of intact erythrocytes to oxidative stress did not change in the elderly group. However, under the same conditions erythrocyte membranes were more susceptible to oxidative damage in the elderly than young adults. Our results also showed that antioxidant defenses were overwhelmed in intact erythrocytes of the elderly at high concentrations of cumene hydroperoxide.

Detection of eicosanoids in epiretinal membranes of patients suffering from proliferative vitreoretinal diseases

AIM

Arachidonic acid is metabolised via lipoxygenase to 15-HETE (15-hydroxyeicosatetraenoic acid) and 15-HPETE (15-hydroperoxyeicosatetraenoic acid), which are believed to influence proliferation in tissue culture. 15-HETE is the reduction product of 15-HPETE. Cell proliferation is believed to be decreased by 15-HPETE and increased by 15-HETE. The aim of this study was to investigate epiretinal membranes for the presence of these lipoxygenase products and to compare membranes from different disease processes.

METHODS

Epiretinal membranes of 15 patients suffering from proliferative vitreoretinopathy (PVR, n = 7) and proliferative diabetic retinopathy (PDR; n = 8) were removed during vitrectomy and analysed by means of thin layer chromatography. The plates were evaluated by digital image analysis.

RESULTS

Both 15-HETE and 15-HPETE were identified in membranes from eyes of patients with PVR and PDR with HETE values significantly higher (p < 0.05) than HPETE values (HETE/HPETE ratio = 5.2).

CONCLUSION

This study demonstrates that eicosanoids are present in the epiretinal membrane tissue of patients with PVR and PDR. Considering that HETE increases cell proliferation while HPETE inhibits it, it is conceivable that eicosanoids are an additional factor contributing to the regulation of membrane growth in proliferative retinal disorders. Thus, inhibition of lipoxygenase could be a therapeutic approach in these diseases.

Flow cytometric evaluation of erythrocyte response to oxidant stress

Erythrocyte response to oxidant challenge has been used as an indicator of cell membrane tolerance to oxidant stress. This study describes a simple technique for evaluation of erythrocyte response to hydrogen peroxide oxidant stress using flow cytometry as an assay method. Challenged cells showed a detectable increase in fluorescence over the basal level. This increase in fluorescence was both concentration and time dependent. The test was standardized using 0.1 mM hydrogen peroxide and 2 h incubation. The standardized test showed a higher fluorescence of challenged umbilical cord erythrocytes compared to challenged adult red blood cells. We recommend further use of this test for examining other populations of red blood cells.