Radioprotective and Radiomitigative Effects of Melatonin in Tissues with Different Proliferative Activity

We used various markers to analyze damage to mouse tissues (spleen and cerebral cortex) which have different proliferative activity and sensitivity to ionizing radiation (IR). We also assessed the degree of modulation of damages that occurs when melatonin is administered to mice prior to and after their X-ray irradiation. The data from this study showed that lesions in nuclear DNA (nDNA) were repaired more actively in the spleen than in the cerebral cortex of mice irradiated and treated with melatonin (N-acetyl-5-methoxytryptamine). Mitochondrial biogenesis involving mitochondrial DNA (mtDNA) synthesis was activated in both tissues of irradiated mice. A significant proportion of the newly synthesized mtDNA molecules were mutant copies that increase oxidative stress. Melatonin reduced the number of mutant mtDNA copies and the level of H2O2 in both tissues of the irradiated mice. Melatonin promoted the restoration of ATP levels in the tissues of irradiated mice. In the mouse tissues after exposure to X-ray, the level of malondialdehyde (MDA) increased and melatonin was able to reduce it. The MDA concentration was higher in the cerebral cortex tissue than that in the spleen tissue of the mouse. In mouse tissues following irradiation, the glutathione (GSH) level was low. The spleen GSH content was more than twice as low as that in the cerebral cortex. Melatonin helped restore the GSH levels in the mouse tissues. Although the spleen and cerebral cortex tissues of mice differ in the baseline values of the analyzed markers, the radioprotective and radiomitigative potential of melatonin was observed in both tissues.

Preparation of Single Cell Suspension from Human Spleen Tissue v1

This protocol describes a method for the isolation of pan-lymphocytes, pan-myeloid cells, and progenitors from human spleen tissue. By providing defined media formulations, volumes at each step, and a defined dilution factor for density centrifugation, it yields consistent single-cell suspensions across samples.

The Effects of Extracellular Vesicles Derived From Krüppel-like Factor 2 Overexpressed Endothelial Cells on the Regulation of Cardiac Inflammation in the Dilated Cardiomyopathy

BackgroundDilated cardiomyopathy (DCM) is one of the common causes of heart failure. Myocardial injury triggers an inflammatory response and recruits immune cells into the heart. High expression of Krüppel-like factor 2(KLF2) in endothelial cells (ECs) could exert the anti-inflammatory effect. However, the role of extracellular vesicles from KLF2-overexpressed ECs (KLF2-EVs) in DCM remains unclear. Methods and ResultsEVs were separated from the supernatant of KLF2-overexpressed ECs by gradient centrifugation. Mice were administered with a repetitive low-dose doxorubicin (DOX) and then received KLF2- EVs through intravenous injection. Treatment with KLF2- EVs prevented doxorubicin-induced left ventricular dysfunction and reduced recruitment of Ly6high Mo/Mø in myocardium. To identify the mechanisms involved in this beneficial effect we used flow cytometry to detect Ly6high monocytes in bone marrow and spleen tissue. KLF2-EVs increased the retention of Ly6Chigh monocytes in the bone marrow, but not the spleen tissue. KLF2-EVs also significantly downregulated C-C chemokine receptor 2(CCR2) protein expression in cells from the bone marrow. ConclusionEVs derived from KLF2-overexpressed ECs reduced cardiac inflammation and ameliorated left ventricular dysfunction in DCM mice, which is achieved by targeting the CCR2 protein to inhibit Ly6Chigh monocytes mobilizing from bone marrow.

Evaluation of splenic accumulation and colocalization of immature reticulocytes and Plasmodium vivax in asymptomatic malaria: A prospective human splenectomy study

Background A very large biomass of intact asexual-stage malaria parasites accumulates in the spleen of asymptomatic human individuals infected with Plasmodium vivax. The mechanisms underlying this intense tropism are not clear. We hypothesised that immature reticulocytes, in which P. vivax develops, may display high densities in the spleen, thereby providing a niche for parasite survival. Methods and findings We examined spleen tissue in 22 mostly untreated individuals naturally exposed to P. vivax and Plasmodium falciparum undergoing splenectomy for any clinical indication in malaria-endemic Papua, Indonesia (2015 to 2017). Infection, parasite and immature reticulocyte density, and splenic distribution were analysed by optical microscopy, flow cytometry, and molecular assays. Nine non-endemic control spleens from individuals undergoing spleno-pancreatectomy in France (2017 to 2020) were also examined for reticulocyte densities. There were no exclusion criteria or sample size considerations in both patient cohorts for this demanding approach. In Indonesia, 95.5% (21/22) of splenectomy patients had asymptomatic splenic Plasmodium infection (7 P. vivax, 13 P. falciparum, and 1 mixed infection). Significant splenic accumulation of immature CD71 intermediate- and high-expressing reticulocytes was seen, with concentrations 11 times greater than in peripheral blood. Accordingly, in France, reticulocyte concentrations in the splenic effluent were higher than in peripheral blood. Greater rigidity of reticulocytes in splenic than in peripheral blood, and their higher densities in splenic cords both suggest a mechanical retention process. Asexual-stage P. vivax-infected erythrocytes of all developmental stages accumulated in the spleen, with non-phagocytosed parasite densities 3,590 times (IQR: 2,600 to 4,130) higher than in circulating blood, and median total splenic parasite loads 81 (IQR: 14 to 205) times greater, accounting for 98.7% (IQR: 95.1% to 98.9%) of the estimated total-body P. vivax biomass. More reticulocytes were in contact with sinus lumen endothelial cells in P. vivax- than in P. falciparum-infected spleens. Histological analyses revealed 96% of P. vivax rings/trophozoites and 46% of schizonts colocalised with 92% of immature reticulocytes in the cords and sinus lumens of the red pulp. Larger splenic cohort studies and similar investigations in untreated symptomatic malaria are warranted. Conclusions Immature CD71+ reticulocytes and splenic P. vivax-infected erythrocytes of all asexual stages accumulate in the same splenic compartments, suggesting the existence of a cryptic endosplenic lifecycle in chronic P. vivax infection. Findings provide insight into P. vivax-specific adaptions that have evolved to maximise survival and replication in the spleen.

Orally Administered Activated Charcoal as a Medical Countermeasure for Acute Radiation Syndrome in Rats

Activated charcoal (AC) can be taken orally as enterosorbent for treatment of pathological states related to exogenous and endogenous intoxications. Synthesized granulated AC with a highly developed active surface (SBET ~2700 m2/g) was used as a medical countermeasure (MCM) to acute radiation sickness (ARS) in rats after total body X-ray irradiation. AC demonstrates positive results in ARS treatment, as expressed in, (i) a decrease in body weight loss, (ii) a protection of bone marrow (BM) cells colony formation capacity, (iii) a reduction of BM chromosomal aberrations and small intestine and spleen tissue damage, (iv) an amelioration of white blood cell count, and (v) a mitigation of superoxide ion generation rate in the liver. AC oral prescription seems to be perspective modality of ARS treatment.

L-glutamic acid effect on changes in biochemical parameters of rats intoxicated by carbon tetrachloride

This study aims to explore the ameliorative effects of L-glutamic acid (L-Glu) against carbon tetrachloride (CCl4) toxicity in male rats. Changes in the activities of alanine and aspartate aminotransferases (ALAT, ASAT) were studied in the tissues and blood of rats. Concentrations of creatinine, triacylglycerol and cholesterol were also determined in the blood of experimental animals. Intraperitoneal administration of CCl4 to rats led to changes in the blood of animals of the studied parameters — an increase of the activities of aminotransferases, triacylglycerol and cholesterol levels. At the same time, a decrease of ALAT activity was observed in the tissues of the myocardium and spleen of intoxicated animals, ASAT in their brain, and in the tissues of the lungs there was an increase in the activity of ALAT and the growth of ASAT in the tissues of the spleen In turn, with additional administration to animals intoxicated with tetrachloromethane L-Glu mitigation or no change in most of the studied indicators was observed, namely, in the blood the activity of ASAT fluctuated within the control values, and the concentrations of triacylglycerol and cholesterol did not change compared to the control. Also under the action of the studied aminoacid, no changes were detected in the activities of ALAT in lung tissue and ASAT in spleen tissue. The obtained results indicate a corrective effect of L-Glu on the physiological and biochemical parameters of rats in their intoxication with carbon tetrachloride.

Interferon-Inducible Transmembrane Protein 3-Containing Exosome as a New Carrier for the Cell-to-Cell Transmission of Anti-Brucella Activity

Exosomes are small extracellular vesicles that are released from cells and that function in intercellular communication. Recently, interferon-inducible transmembrane protein 3 (IFITM3) has been identified as a highly effective anti-intracellular pathogen protein that can inhibit the invasion of a wide range of pathogenic microorganisms. However, whether Brucella infection induces secretion of exosomes and whether these exosomes contain IFITM3 protein remain unknown. Here, we focused on the immune function of extracellular IFITM3 protein in the process of Brucella infection. This study is the first to show that Brucella melitensis strain M5 (Brucella M5) can stimulate macrophages to secrete large amounts of exosomes. Most importantly, we identified exosomes from Brucella M5-infected cells that were rich in molecules of IFITM3, and these exosomes could transmit the IFITM3 from one cell to another, thereby effectively inhibiting the intracellular survival of Brucella. Moreover, immunization with exosomes carrying IFITM3 decreased mouse spleen tissue damage and spleen colony forming unit (CFU), leading to the establishment of an anti-Brucella state in mice. In conclusion, our findings provide new insights into the anti-Brucella mechanism of IFITM3-containg exosomes, thus providing a theoretical foundation for systematic elaboration of the mechanisms of Brucella infection and host immunity. The results provide new ideas for the development of candidate vaccines for Brucella.

Technique for Spleen Resection Using Radiofrequency Ablation

From modern positions, removal of the spleen is undesirable due to the risk of post-splenectomy syndrome development, where first of all, the clinical manifestations of the syndrome of suppressive post-splenectomy infections are taken into account, which justifies either performing organ-preserving surgical interventions on the spleen, or heterotopic autotransplantation of spleen tissue. Spleen resection is accompanied by significant blood loss, both during the intervention and in the postoperative period. The various methods of prevention of bleeding (clips, coagulation instruments, local hemostatics, etc.) are not always effective. Currently, there have been reports of the possibility of using radiofrequency ablation (RFA) in interventions on the spleen. The literature data and own 10 observations of spleen resection with the use of RFA in patients with focal organ lesions are presented. All described in literature technologies use the Rita® device for RF destruction and the corresponding attachment, which consists of 4 needle active electrodes. The spleen parenchyma is "burned" blindly, and the organ parenchyma is divided in the middle, between the treated injections. A new technique for performing spleen resection using radiofrequency ablation has been proposed at A.V. Vishnevsky National Medical Research Center of Surgery. The essence of our proposed method for minimizing blood loss during spleen resection is as follows: RFA-exposure is carried out along the zone of organ ischaemia under the control of ultrasound. For RFA, we used a Radionics Cool-Tip® Ablation System and a set of water-cooled electrodes (MEDTRONIC, USA). The features of the surgical intervention are noted. No bleeding was noted either intraoperatively or in the postoperative period in any case. A comparative analysis of the results of various methods of organ-saving surgical treatment is presented.

Identifications of immune-responsive genes for adaptative traits by comparative transcriptome analysis of spleen tissue from Kazakh and Suffolk sheep

Aridity and heat are significant environmental stressors that affect sheep adaptation and adaptability, thus influencing immunity, growth, reproduction, production performance, and profitability. The aim of this study was to profile mRNA expression levels in the spleen of indigenous Kazakh sheep breed for comparative analysis with the exotic Suffolk breed. Spleen histomorphology was observed in indigenous Kazakh sheep and exotic Suffolk sheep raised in Xinjiang China. Transcriptome sequencing of spleen tissue from the two breeds were performed via Illumina high-throughput sequencing technology and validated by RT-qPCR. Blood cytokine and IgG levels differed between the two breeds and IgG and IL-1β were significantly higher in Kazakh sheep than in Suffolk sheep (p < 0.05), though spleen tissue morphology was the same. A total of 52.04 Gb clean reads were obtained and the clean reads were assembled into 67,271 unigenes using bioinformatics analysis. Profiling analysis of differential gene expression showed that 1158 differentially expressed genes were found when comparing Suffolk with Kazakh sheep, including 246 up-regulated genes and 912 down-regulated genes. Utilizing gene ontology annotation and pathway analysis, 21 immune- responsive genes were identified as spleen-specific genes associated with adaptive traits and were significantly enriched in hematopoietic cell lineage, natural killer cell-mediated cytotoxicity, complement and coagulation cascades, and in the intestinal immune network for IgA production. Four pathways and up-regulated genes associated with immune responses in indigenous sheep played indispensable and promoting roles in arid and hot environments. Overall, this study provides valuable transcriptome data on the immunological mechanisms related to adaptive traits in indigenous and exotic sheep and offers a foundation for research into adaptive evolution.