scholarly journals Splenic Mechanisms of Thrombocytopenia

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-33-SCI-33
Author(s):  
John W. Semple
Keyword(s):  
Immune Responses ◽  
Reticuloendothelial System ◽  
Lymphoid Organ ◽  
The Body ◽  
White Pulp ◽  
Cellular Mechanisms ◽  
Venous Circulation ◽  
Destructive Processes ◽  
Clinical Conditions ◽  
Red Pulp

The spleen is the largest secondary lymphoid organ in the body and contains up to 25 percent of the body's lymphocyte populations. It is not only responsible for initiating immune responses against a multitude of infectious antigens within its white pulp, it also has the exquisite ability to filter the blood and remove, for example, senescent erythrocytes and platelets. This natural process is carried out within the red pulp of the spleen which is composed monocyte-rich connective tissue cords of Billroth intertwined with sinus cavities lined by parallel-oriented endothelial cells that have interendothelial slits which allow for the mechanical sorting of "old" cells. This occurs because of the inability of the senescent cells to properly migrate through the endothelial fenestrae into the venous circulation allowing them to be identified by cells of the reticuloendothelial system (RES) and quickly destroyed by phagocytosis. This process also allows for the efficient recycling of iron from destroyed erythrocyte hemoglobin molecules. There are a wide variety of clinical conditions that can significantly alter the ability of the RES to destroy blood cells including hereditary blood cell defects, inflammation, cancer and abnormal immune responses. This lecture will focus on the central role that the spleen plays in not only generating immune responses against platelets but also in primarily causing the destruction of both senescent and antibody-opsonized platelets leading to thrombocytopenia. It will discuss the soluble and cellular mechanisms of splenic sequestration, destruction and the ability of the spleen to modulate anti-platelet immunity. Mechanisms involving complement activation, Fc Receptor-mediated phagocytosis, antibody dependent cellular cytotoxicity and platelet self-destruction will be addressed. It will compare the spleen's platelet destructive capabilities with other organs, particularly the liver and will detail how immune responses generated in the white pulp can modulate platelet destructive processes in the red pulp. Disclosures Semple: Amgen: Consultancy, Honoraria, Speakers Bureau; Rigel: Consultancy, Honoraria; UCB: Consultancy, Honoraria.

Splenomegaly and other disorders of the spleen

2018 ◽  
Author(s):  
Chris Bunch
Keyword(s):  
Particulate Matter ◽  
Immune Responses ◽  
Lymphoid Tissue ◽  
Lymphoid Organ ◽  
Dual Role ◽  
White Pulp ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Upper Abdomen ◽  
Red Pulp

The spleen is a predominantly lymphoid organ, normally about the size of a clenched fist located beneath the diaphragm in the left upper abdomen. It has a dual role as a filter for the circulation, and a primary lymphoid organ in its own right. About three-quarters of its volume is a matrix of capillaries and sinuses (the red pulp), through which blood is able to percolate slowly and come into contact with fixed macrophages, which are able to remove senescent or damaged red cells, or other particulate matter such as bacteria. The lymphoid tissue is organized into scattered follicles (the white pulp), which have a particularly important role in initiating primary humoral immune responses and antibody (IgM) synthesis. The spleen commonly enlarges when either its filtration function is increased—as in haemolysis—or it is stimulated by infection or inflammation. It may also be involved in myeloproliferative and lymphoproliferative neoplasias. This chapter covers hypersplenism, splenectomy, hyposplenism, overwhelming post-splenectomy infection (OPSI), and other infections in hyposplenic patients.

Reticuloendothelial System: The Basics

2018 ◽  
pp. 617-625
Author(s):  
Jenny X. Qian ◽  
Bradley B. Pua
Keyword(s):  
Reticuloendothelial System ◽  
Lymphoid Organ ◽  
Primary Site ◽  
Malignant Neoplasms ◽  
White Pulp ◽  
Vital Function ◽  
Abnormal Cells ◽  
Upper Abdomen

The spleen is the largest organ of the reticuloendothelial system and the largest lymphoid organ. Derived from embryologic mesoderm, it is a solid, intraperitoneal organ situated in the left upper abdomen, lateral and slightly posterior to the stomach. Long thought to be a superfluous structure, the spleen is now known to play a major role in immunity, as asplenic patients are predisposed to sepsis from encapsulated organisms. It is also an important reservoir for platelets, monocytes, and erythrocytes, and it performs the vital function of filtering the blood to remove senescent or abnormal cells, as well as circulating debris. Its ability to perform these functions is closely tied to the microarchitecture of both its red- and white-pulp components. In addition, the spleen plays an important role in the development of many diseases, and may be secondarily involved or, more rarely, the primary site of malignant neoplasms such as lymphoma.

Role of convalescent plasma therapy in new Coronavirus disease (nCOVID-19): A review

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 546-549
Author(s):  
Shweta Dadarao Parwe ◽  
Milind Abhimanyu Nisargandha ◽  
Rishikesh Thakre
Keyword(s):  
Clinical Trial ◽  
Immune Responses ◽  
Indian Population ◽  
Preventive Treatment ◽  
The Body ◽  
Therapeutic Antibodies ◽  
Plasma Therapy ◽  
Host Immune Responses ◽  
Transparent Liquid

Hitherto, there is no proper line of treatment for the new (nCOVID19). The development of unique antiviral drugs has taken precedence. Therapeutic antibodies () will be a significantly beneficial agent against nCOVID-19. Here the host immune responses to new discussed in this review provide strategy and further treatment and understanding of clinical interventions against nCOVID-19. Plasma therapy uses the antibodies found in the blood of people recovering (or convalesced) from an infection to treat infected patients. When an infection occurs, the body begins producing proteins specially made to kill the germ, called antibodies. Those antibodies coat specifically plasma in the blood of survivors, the yellow transparent liquid blood portion for months or even years. research assesses plasma use from Convalescent patients of infected with nCOVID-19 as a possible preventive treatment. But it is not yet recommended as a line of treatment, and it is used as a clinical trial in the new in Indian population.

scholarly journals Effects of Inbreeding on Genetic Characteristic, Growth, Survival Rates, and Immune Responses of a New Inbred Line of Exopalaemon carinicauda

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jiajia Wang ◽  
Jitao Li ◽  
Qianqian Ge ◽  
Zhao Chen ◽  
Jian Li
Keyword(s):  
Immune Responses ◽  
Inbred Line ◽  
Survival Rates ◽  
The Body ◽  
Exopalaemon Carinicauda ◽  
Economic Traits ◽  
Gene Frequencies ◽  
Research Fields ◽  
Ssr Loci ◽  
Genetic Detection

The Exopalaemon carinicauda could be a useful crustacean laboratory animal in many research fields. We newly established an inbred line of Exopalaemon carinicauda named EC4 inbred line by brother×sister mating and keeping to F11 generation. Trends in heterozygosity in the process of producing EC4 inbred line were examined through the characterization of polymorphisms based on gene frequencies of SNP and EST-SSR loci. The results demonstrated that the number of alleles (N), observed heterozygosity (Ho), expected heterozygosity (He), and polymorphism information content (PIC) gradually decreased with the increase of inbreeding generations. The genetic detection results indicated that 9 (29.03%, 9/31) of the SNP loci and 15 (32.61%, 15/46) of the EST-SSR loci were homozygous in F11 generation of EC4 inbred line. The variation of the growth-related traits, the immune responses, and antioxidant status were described in experimental full-sibling inbred populations of E. carinicauda at five levels of inbreeding coefficient (F=0.785, F=0.816, F=0.859, F=0.886, F=0.908) under controlled laboratory conditions. The body weight, body length, and survival rate in EC4 inbred line of all generations were less than the control population. Inbreeding affected the antibacterial activity, phenoloxidase (PO) activity, and superoxide dismutase (SOD) which decreased at the eleventh generation of EC4 inbred line. This study demonstrated that inbreeding had a negative effect on the economic traits and immune response, but our inbred line was established successfully until F11 and confirmed by genetic detection using SNP and EST-SSR loci.

scholarly journals Extracellular Vesicles of Mesenchymal Stem Cells: Therapeutic Properties Discovered with Extraordinary SuccessOK

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 667
Author(s):  
Gabriella Racchetti ◽  
Jacopo Meldolesi
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Immune Responses ◽  
Extracellular Vesicles ◽  
Immune Regulation ◽  
Great Increase ◽  
The Body ◽  
Cell Aging ◽  
Therapeutic Effects ◽  
Therapeutic Properties

Mesenchymal stem cells (MSCs), the cells distributed in the stromas of the body, are known for various properties including replication, the potential of various differentiations, the immune-related processes including inflammation. About two decades ago, these cells were shown to play relevant roles in the therapy of numerous diseases, dependent on their immune regulation and their release of cytokines and growth factors, with ensuing activation of favorable enzymes and processes. Such discovery induced great increase of their investigation. Soon thereafter, however, it became clear that therapeutic actions of MSCs are risky, accompanied by serious drawbacks and defects. MSC therapy has been therefore reduced to a few diseases, replaced for the others by their extracellular vesicles, the MSC-EVs. The latter vesicles recapitulate most therapeutic actions of MSCs, with equal or even better efficacies and without the serious drawbacks of the parent cells. In addition, MSC-EVs are characterized by many advantages, among which are their heterogeneities dependent on the stromas of origin, the alleviation of cell aging, the regulation of immune responses and inflammation. Here we illustrate the MSC-EV therapeutic effects, largely mediated by specific miRNAs, covering various diseases and pathological processes occurring in the bones, heart and vessels, kidney, and brain. MSC-EVs operate also on the development of cancers and on COVID-19, where they alleviate the organ lesions induced by the virus. Therapy by MSC-EVs can be improved by combination of their innate potential to engineering processes inducing precise targeting and transfer of drugs. The unique properties of MSC-EVs explain their intense studies, carried out with extraordinary success. Although not yet developed to clinical practice, the perspectives for proximal future are encouraging.

scholarly journals Selenium deficiency induces spleen pathological changes in pigs by decreasing selenoprotein expression, evoking oxidative stress, and activating inflammation and apoptosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shuang Li ◽  
Wenjuan Sun ◽  
Kai Zhang ◽  
Jiawei Zhu ◽  
Xueting Jia ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Inflammatory Cytokines ◽  
The Body ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Antioxidant Systems ◽  
Tunel Staining ◽  
White Pulp ◽  
Sibling Pairs ◽  
Se Deficiency ◽  
Spleen Index

Abstract Background The immune system is one aspect of health that is affected by dietary selenium (Se) levels and selenoprotein expression. Spleen is an important immune organ of the body, which is directly involved in cellular immunity. However, there are limited reports on Se levels and spleen health. Therefore, this study established a Se-deficient pig model to investigate the mechanism of Se deficiency-induced splenic pathogenesis. Methods Twenty-four pure line castrated male Yorkshire pigs (45 days old, 12.50 ± 1.32 kg, 12 full-sibling pairs) were divided into two equal groups and fed Se-deficient diet (0.007 mg Se/kg) or Se-adequate diet (0.3 mg Se/kg) for 16 weeks. At the end of the trial, blood and spleen were collected to assay for erythroid parameters, the osmotic fragility of erythrocytes, the spleen index, histology, terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) staining, Se concentrations, the selenogenome, redox status, and signaling related inflammation and apoptosis. Results Dietary Se deficiency decreased the erythroid parameters and increased the number of osmotically fragile erythrocytes (P < 0.05). The spleen index did not change, but hematoxylin and eosin and TUNEL staining indicated that the white pulp decreased, the red pulp increased, and splenocyte apoptosis occurred in the Se deficient group. Se deficiency decreased the Se concentration and selenoprotein expression in the spleen (P < 0.05), blocked the glutathione and thioredoxin antioxidant systems, and led to redox imbalance. Se deficiency activated the NF-κB and HIF-1α transcription factors, thus increasing pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, and TNF-α), decreasing anti-inflammatory cytokines (IL-10, IL-13, and TGF-β) and increasing expression of the downstream genes COX-2 and iNOS (P < 0.05), which in turn induced inflammation. In addition, Se-deficiency induced apoptosis through the mitochondrial pathway, upregulated apoptotic genes (Caspase3, Caspase8, and Bak), and downregulated antiapoptotic genes (Bcl-2) (P < 0.05) at the mRNA level, thus verifying the results of TUNEL staining. Conclusions These results indicated that Se deficiency induces spleen injury through the regulation of selenoproteins, oxidative stress, inflammation and apoptosis.

Immunometabolism of obesity and diabetes: microbiota link compartmentalized immunity in the gut to metabolic tissue inflammation

2015 ◽  
Vol 129 (12) ◽  
pp. 1083-1096 ◽  
Author(s):  
Joseph B. McPhee ◽  
Jonathan D. Schertzer
Keyword(s):  
Metabolic Disease ◽  
Type 2 Diabetes ◽  
Immune Responses ◽  
Metabolic Diseases ◽  
The Body ◽  
Tissue Inflammation ◽  
Gut Barrier Function ◽  
Inflammatory Status ◽  
Obesity And Diabetes

The bacteria that inhabit us have emerged as factors linking immunity and metabolism. Changes in our microbiota can modify obesity and the immune underpinnings of metabolic diseases such as Type 2 diabetes. Obesity coincides with a low-level systemic inflammation, which also manifests within metabolic tissues such as adipose tissue and liver. This metabolic inflammation can promote insulin resistance and dysglycaemia. However, the obesity and metabolic disease-related immune responses that are compartmentalized in the intestinal environment do not necessarily parallel the inflammatory status of metabolic tissues that control blood glucose. In fact, a permissive immune environment in the gut can exacerbate metabolic tissue inflammation. Unravelling these discordant immune responses in different parts of the body and establishing a connection between nutrients, immunity and the microbiota in the gut is a complex challenge. Recent evidence positions the relationship between host gut barrier function, intestinal T cell responses and specific microbes at the crossroads of obesity and inflammation in metabolic disease. A key problem to be addressed is understanding how metabolite, immune or bacterial signals from the gut are relayed and transferred into systemic or metabolic tissue inflammation that can impair insulin action preceding Type 2 diabetes.

Tumor Microenvironment-Triggered In-Situ Cancer Vaccines with Dual Immunogenic Cell Death Inductions for Elevated Antitumor and Antimetastatic Therapy

Nanoscale ◽  
2021 ◽  
Author(s):  
Jun Lin ◽  
Binbin Ding ◽  
Pan Zheng ◽  
Dong Li ◽  
Meifang Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Microenvironment ◽  
Immune Responses ◽  
Cancer Immunotherapy ◽  
Cancer Vaccines ◽  
High Specificity ◽  
The Body ◽  
Immunogenic Cell Death ◽  
Specific Antigens

Cancer vaccine is to make tumor-specific antigens into vaccines, which then are injected back into the body to activate immune responses for cancer immunotherapy. Despite the high specificity and therapeutic...

scholarly journals The thymus and the science of self

2021 ◽  
Author(s):  
Vincent Geenen
Keyword(s):  
T Cells ◽  
Adaptive Immune System ◽  
Lymphoid Organ ◽  
The Body ◽  
Effector Cells ◽  
Major Organ ◽  
Organ Specific ◽  
Health And Disease ◽  
Essential State ◽  
The 1960S

AbstractThe conventional perception asserts that immunology is the science of ‘discrimination’ between self and non-self. This concept is however no longer tenable as effector cells of the adaptive immune system are first conditioned to be tolerant to the body’s own antigens, collectively known as self until now. Only then attain these effectors the responsiveness to non-self. The acquisition of this essential state of tolerance to self occurs for T cells in the thymus, the last major organ of our body that revealed its intricate function in health and disease. The ‘thymus’ as an anatomical notion was first notably documented in Ancient Greece although our present understanding of the organ’s functions was only deciphered commencing in the 1960s. In the late 1980s, the thymus was identified as the site where clones of cells reactive to self, termed ‘forbidden’ thymocytes, are physically depleted as the result of a process now known as negative selection. The recognition of this mechanism further contributed to the belief that the central rationale of immunology as a science lies in the distinction between self and non-self. This review will discuss the evidence that the thymus serves as a unique lymphoid organ able to instruct T cells to recognize and be tolerant to harmless self before adopting the capacity to defend the body against potentially injurious non-self-antigens presented in the context of different challenges from infections to exposure to malignant cells. The emerging insight into the thymus’ cardinal functions now also provides an opportunity to exploit this knowledge to develop novel strategies that specifically prevent or even treat organ-specific autoimmune diseases.

Mesenchymal stem cells induce the expansion of regulatory T cells in abortion-prone mice

Reproduction ◽  
2021 ◽  
Author(s):  
Amir Salek Farrokhi ◽  
Amir-Hassan Zarnani ◽  
Fatemeh Rezaei kahmini ◽  
Seyed Mohammad Moazzeni
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Mesenchymal Stem Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Lymph Nodes ◽  
De Novo ◽  
Abortion Rate ◽  
Cellular Mechanisms ◽  
Inguinal Lymph Nodes

Recurrent pregnancy loss (RPL) is one of the most common complications of early pregnancy associated in most cases with local or systemic immune abnormalities such as the diminished proportion of regulatory T cells (Tregs). Mesenchymal stem cells (MSCs) have been shown to modulate immune responses by de novo induction and expansion of Tregs. In this study, we analyzed the molecular and cellular mechanisms involved in Treg-associated pregnancy protection following MSCs administration in an abortion-prone mouse mating. In a case-control study, syngeneic abdominal fat-derived MSCs were administered intraperitoneally (i.p) to the DBA/2-mated CBA/J female mice on day 4.5 of pregnancy. Abortion rate, Tregs proportion in spleen and inguinal lymph nodes, and Ho1, Foxp3, Pd1, and Ctla4 genes expression at the feto-maternal interface were then measured on day 13.5 of pregnancy using flow cytometry and quantitative RT- PCR, respectively. The abortion rate in MSCs-treated mice was significantly reduced and normalized to the level observed in normal pregnant animals. We demonstrated a significant induction of Tregs in inguinal lymph nodes but not in the spleen following MSCs administration. Administration of MSCs remarkably upregulated the expression of HO1, Foxp3, Pd1, and Ctla4 genes in both placenta and decidua. Here, we show that MSCs therapy could protect the fetus in the abortion-prone mice through Tregs expansion and up-regulation of Treg-related genes. These events could establish an immune-privileged microenvironment, which participates in regulation of detrimental maternal immune responses against the semi-allogeneic fetus.

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