Oligodendrocyte pathology in fetal alcohol spectrum disorders

The pathology of fetal alcohol syndrome and the less severe fetal alcohol spectrum disorders includes brain dysmyelination.Recent studies have shed light on the molecular mechanisms underlying these white matter abnormalities.Rodent models of fetal alcohol syndrome and human studies have shown suppressed oligodendrocyte differentiation and apoptosis of oligodendrocyte precursor cells.Ethanol exposure led to reduced expression of myelin basic protein and delayed myelin basic protein expression in rat and mouse models of fetal alcohol syndrome and in human histopathological specimens.Several studies have reported increased expression of many chemokines in dysmyelinating disorders in central nervous system,including multiple sclerosis and fetal alcohol syndrome.Acute ethanol exposure reduced levels of the neuroprotective insulin-like growth factor-1 in fetal and maternal sheep and in human fetal brain tissues,while ethanol increased the expression of tumor necrosis factor α in mouse and human neurons.White matter lesions have been induced in the developing sheep brain by alcohol exposure in early gestation.Rat fetal alcohol syndrome models have shown reduced axon diameters,with thinner myelin sheaths,as well as reduced numbers of oligodendrocytes,which were also morphologically aberrant oligodendrocytes.Expressions of markers for mature myelination,including myelin basic protein,also were reduced.The accumulating knowledge concerning the mechanisms of ethanol-induced dysmyelination could lead to the development of strategies to prevent dysmyelination in children exposed to ethanol during fetal development.Future studies using fetal oligodendrocyte-and oligodendrocyte precursor cell-derived exosomes isolated from the mother's blood may identify biomarkers for fetal alcohol syndrome and even implicate epigenetic changes in early development that affect oligodendrocyte precursor cell and oligodendrocyte function in adulthood.By combining various imaging modalities with molecular studies,it may be possible to determine which fetuses are at risk and to intervene therapeutically early in the pregnancy.     

In Vitro Susceptibility of Wistar Rat Platelets to Hydrogen Peroxide and AAPH-Induced Oxidative Stress

Hydroxyl and peroxyl radicals are biologically active species because of their likelihood to damage cellular constituents. An in vitro study on Wistar rats was conducted to investigate the influence of hydrogen peroxide (H₂O₂) and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) on platelets and compare the vulnerability of platelets to oxidative stress (OS) induced by these two free radical initiators. Isolated platelets were divided into controls (without free radical initiators; n = 5) and experimentals (with free radical initiators; n = 5). Different concentrations (0.5, 1.0 and 2.0) of free radical initiators H₂O₂ and AAPH were used to treat the platelets and incubated for 5, 15 and 30 min. Biomarkers such as platelet aggregation, superoxide generation, lipid peroxidation (thiobarbituric acid reactive substances, conjugate dienes), protein oxidation (protein carbonyls, sulfhydryls) and antioxidant enzymes were assessed. In H₂O₂ and AAPH treated platelets, though OS was observed at concentrations of 0.5 and 1.0 mM, platelets could tolerate the oxidative insult. Treatment of platelets with 2.0 mM H₂O₂ demonstrated the onset of irreversible changes in platelets as observed in the results of increased superoxide generation and lipid peroxidation products. In 2.0 mM AAPH platelets, the oxidative damage was evident as indicated through increased aggregation, superoxide generation and conjugate dienes and lower protein sulfhydryls. Platelets were more susceptible to AAPH than H₂O₂, as AAPH acted on both lipids and proteins whereas H₂O₂ acted only on lipids. This study gives insight on platelet survival under different OS situations.     

Phytochemicals as potential therapeutics for thrombocytopenia

Medical knowledge has always relied on plants as the main sources of important beneficial compounds. Many species have been recognized to have medicinal properties and beneficial impact on health, e.g. antioxidant activity, digestive stimulation action, anti-inflammatory, antimicrobial, hypolipidemic, antimutagenic and anticarcinogenic potential. This review focuses on the promising role of plants and their products in attenuating thrombocytopenia, a common and complex bleeding disorder. When the platelet count decreases below 150,000/µl, it causes thrombocytopenia. This bleeding disorder is observed in 2.5 % of the normal population. The risk of spontaneous muco-cutaneous bleeding and life threatening intracranial haemorrhage or gastrointestinal bleeding increases rapidly when the platelet count decreases below 10,000/µl. The inability to provide supportive treatment to increase the platelet counts often proves fatal to patients. Currently, treatment for thrombocytopenia includes use of drugs or splenectomy or platelet transfusions, in severe cases. Recently, studies have shown platelet augmenting activity of various plant extracts. The effectiveness, toxicity and side effects of the phytochemicals have to be critically evaluated in clinical trials. An in depth understanding of the role and mechanism of these phytochemicals would lead to their successful implementation in treatment and management of thrombocytopenia and other related bleeding disorders.     

Development and characterization of highly selective target-sensitive liposomes for the delivery of streptokinase: in vitro/in vivo studies

Streptokinase is one of the most commonly used thrombolytic agents for the treatment of thromboembolism. Short half-life of the streptokinase requires administration of higher dose which results in various side effects including systemic haemorrhage due to activation of systemic plasmin. To increase the selectivity of the streptokinase and hence to reduce side effects, various novel carriers have been developed. Among these carriers, liposomes have been emerged as versatile carrier. In the present study, highly selective target-sensitive liposomes were developed and evaluated by in vitro and in vivo studies. Prepared liposomes were found to release streptokinase in vitro following binding with activated platelets. Intravital microscopy studies in thrombosed murine model revealed higher accumulation of liposomes in the thrombus area. In vivo thrombolysis study was performed in the human clot inoculated rat model. Results of the study showed that target-sensitive liposomes dissolved 28.27?±?1.56% thrombus as compared to 17.18?±?1.23% of non-liposomal streptokinase. Further, it was also observed that target-sensitive liposomes reduced the clot dissolution time as compared to streptokinase solution. Studies concluded that developed liposomes might be pragmatic carriers for the treatment of thromboembolism.     

The VEXAS syndrome from rheumatology perspective: genomic DNA sequencing as available blueprint for diagnosing rheumatic diseases with overlapping haematological or dermatological findings

Clinical Rheumatology -     

Challenges in delivering rheumatology care during COVID-19 pandemic

Clinical Rheumatology - COVID-19 has significantly affected healthcare systems around the world. To prepare for this unprecedented emergency, elective patient care was put on hold across the...