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Scurvy is a nutritional deficiency caused by low vitamin C levels that has been described since ancient times. It leads to a varied presentation, affecting multiple organ systems due to its role in the biochemical reactions of connective tissue synthesis. Common manifestations include gingival bleeding, arthralgias, skin discoloration, impaired wound healing, perifollicular hemorrhage, and ecchymoses. Although there has been a dramatic reduction in the prevalence of scurvy in modern times owing to vitamin C supplementation and intake, sporadic cases still occur. In developed countries, it is mainly diagnosed in the elderly and malnourished individuals and is associated with alcoholism, low socio-economic status, and poor dietary habits. Scurvy has been an unusual cause of gastrointestinal (GI) bleeding among other GI manifestations. It can be adequately treated and prevented via vitamin C supplementation.

Background: Numerous changes in maternal physiology occur during pregnancy that are critical in controlling and maintaining the maternal metabolic adaptations and fetal development. The placenta is the key source through which the fetus receives nutrients, blood, and oxygen for growth. The human placenta releases several molecules into maternal circulation that include hormones, proteins, RNA, and DNA throughout the course of pregnancy. Additionally, extracellular vesicles (EVs) originating from the placenta have been found in the maternal circulation. Methods: In this review, we discuss the role of EVs in maternal-fetal communication during pregnancy. Results: EVs originating from the placenta can be divided into 3 categories based on their size and/or origin: exosomes (50 to 150 nm), microvesicles (nm to several μm), and apoptotic bodies or syncytial nuclear aggregates (>1 μm). The cellular microenvironment-such as oxygen tension and glucose concentration-have been found to control EV release from the placenta and their bioactivity on target cells. Furthermore, maternal EVs can stimulate cytokine release from endothelial cells and are involved in several physiologic and pathologic events in pregnancy. Conclusion: Exosomes provide a way to identify the function and metabolic state of cell origin through their ability to reflect the microenvironment that they are released from. Further understanding of how EVs regulate key events in pregnancy may help elucidate how maternal-fetal communication is established in both normal and pathologic conditions., (©2020 by the author(s); Creative Commons Attribution License (CC BY).)

Chemoresistance is one of the major obstacles in the treatment of cancer patients. It poses a fundamental challenge to the effectiveness of chemotherapy and is often linked to relapse in patients. Chemoresistant cells can be identified in different types of cancers; however, ovarian cancer has one of the highest rates of chemoresistance-related relapse (50% of patients within 5 years). Resistance in cells can either develop through prolonged cycles of treatment or through intrinsic pathways. Mechanistically, the problem of drug resistance is complex mainly because numerous factors are involved, such as overexpression of drug efflux pumps, drug inactivation, DNA repair mechanisms and alterations to and/or mutations in the drug target. Additionally, there is strong evidence that circulating miRNAs participate in the development of chemoresistance. Recently, miRNAs have been identified in exosomes, where they are encapsulated and hence protected from degradation. These miRNAs within exosomes (exo-miRNAs) can regulate the gene expression of target cells both locally and systemically. Exo-miRNAs play an important role in disease progression and can potentially facilitate chemoresistance in cancer cells. In addition, and from a diagnostic perspective, exo-miRNAs profiles may contribute to the development of predictive models to identify responder and non-responder chemotherapy. Such model may also be used for monitoring treatment response and disease progression. Exo-miRNAs may ultimately serve as both a predictive biomarker for cancer response to therapy and as a prognostic marker for the development of chemotherapy resistance. Therefore, this review examines the potential role of exo-miRNAs in chemotherapy in ovarian cancer.

There is increasing evidence that miRNAs, which are enriched in nanovesicles called exosomes, are important regulators of gene expression. When compared with normal pregnancies, pregnancies with gestational diabetes mellitus (GDM) are associated with skeletal muscle insulin resistance as well as increased levels of circulating placental exosomes. Here we investigated whether placental exosomes in GDM carry a specific set of miRNAs associated with skeletal muscle insulin sensitivity. Exosomes were isolated from chorionic villous (CV) explants from both women with Normal Glucose Tolerant (NGT) and GDM pregnancies. Using miRNA sequencing, we identified a specific set of miRNAs selectively enriched with exosomes and compared with their cells of origin indicating a specific packaging of miRNAs into exosomes. Gene target and ontology analysis of miRNA differentially expressed in exosomes secreted in GDM compared with NGT are associated with pathways regulating cell migration and carbohydrate metabolism. We determined the expression of a selected set of miRNAs in placenta, plasma, and skeletal muscle biopsies from NGT and GDM. Interestingly, the expression of these miRNAs varied in a consistent pattern in the placenta, in circulating exosomes, and in skeletal muscle in GDM. Placental exosomes from GDM pregnancies decreased insulin-stimulated migration and glucose uptake in primary skeletal muscle cells obtained from patients with normal insulin sensitivity. Interestingly, placental exosomes from NGT increase migration and glucose uptake in response to insulin in skeletal muscle from diabetic subjects. These findings suggest that placental exosomes might have a role in the changes on insulin sensitivity in normal and GDM pregnancies., (© 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

For many years, cardiovascular disease (CVD) has been the leading cause of death around the world. Often associated with CVD are comorbidities such as obesity, abnormal lipid profiles and insulin resistance. Insulin is a key hormone that functions as a regulator of cellular metabolism in many tissues in the human body. Insulin resistance is defined as a decrease in tissue response to insulin stimulation thus insulin resistance is characterized by defects in uptake and oxidation of glucose, a decrease in glycogen synthesis, and, to a lesser extent, the ability to suppress lipid oxidation. Literature widely suggests that free fatty acids are the predominant substrate used in the adult myocardium for ATP production, however, the cardiac metabolic network is highly flexible and can use other substrates, such as glucose, lactate or amino acids. During insulin resistance, several metabolic alterations induce the development of cardiovascular disease. For instance, insulin resistance can induce an imbalance in glucose metabolism that generates chronic hyperglycemia, which in turn triggers oxidative stress and causes an inflammatory response that leads to cell damage. Insulin resistance can also alter systemic lipid metabolism which then leads to the development of dyslipidemia and the well-known lipid triad: (1) high levels of plasma triglycerides, (2) low levels of high-density lipoprotein, and (3) the appearance of small dense low-density lipoproteins. This triad, along with endothelial dysfunction, which can also be induced by aberrant insulin signaling, contribute to atherosclerotic plaque formation. Regarding the systemic consequences associated with insulin resistance and the metabolic cardiac alterations, it can be concluded that insulin resistance in the myocardium generates damage by at least three different mechanisms: (1) signal transduction alteration, (2) impaired regulation of substrate metabolism, and (3) altered delivery of substrates to the myocardium. The aim of this review is to discuss the mechanisms associated with insulin resistance and the development of CVD. New therapies focused on decreasing insulin resistance may contribute to a decrease in both CVD and atherosclerotic plaque generation.

Exosomes are small (~100 nm) vesicles that carry a wide range of molecules including proteins, RNAs, and DNA. Exosomes are secreted from a wide range of cells including placental cells. Interestingly, exosomes secreted from placental cells have been identified in maternal circulation as early as in 6 weeks of gestation, and their concentration increases with the gestational age. While there is growing interest in elucidating the role of exosomes during normal and complicated pregnancies (such as preeclampsia), progress in the field has been delayed because of the inability to isolate placental exosomes from maternal circulation. Therefore, here we describe a workflow to isolate placental exosomes from maternal circulation.

Analysis of the human genome revealed that only 1.2% encoded for proteins, which raised questions regarding the biological significance of the remaining genome. We now know that approximately 80% of the genome serves at least one biochemical function within the cell. A portion of this 80% consists of a family of non-coding regulatory RNAs, one important member being microRNAs (miRNAs). miRNAs can be detected in tissues and biofluids, where miRNAs in the latter can be bound to proteins or encapsulated within lipid vesicles such as exosomes. Gestational diabetes mellitus (GDM) is a complication of pregnancy, which has harmful health impacts on both the fetus as well as the mother. The incidence of GDM worldwide varies, but reached 18% in the HAPO cohort using the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. Not only has GDM been associated with increased risks of further complications during pregnancy, but also poses long-term risks for both the mother and the baby. Thus, understanding the pathophysiology of GDM is important from a public health perspective. Literature has demonstrated that GDM is associated with elevated levels of circulating exosomes in maternal circulation. However, there is a paucity of data defining the expression, role, and diagnostic utility of miRNAs in GDM. This review briefly summarizes recent advances in the function and quantification of intracellular and extracellular miRNAs in GDM., (Copyright © 2016. Published by Elsevier Ltd.)

The maternal physiology experiences numerous changes during pregnancy which are essential in controlling and maintaining maternal metabolic adaptations and fetal development. The human placenta is an organ that serves as the primary interface between the maternal and fetal circulation, thereby supplying the fetus with nutrients, blood and oxygen through the umbilical cord. During gestation, the placenta continuously releases several molecules into maternal circulation, including hormones, proteins, RNA and DNA. Interestingly, the presence of extracellular vesicles (EVs) of placental origin has been identified in maternal circulation across gestation. EVs can be categorised according to their size and/or origin into microvesicles (∼150-1000 nm) and exosomes (∼40-120 nm). Microvesicles are released by budding from the plasmatic membrane, whereas exosome release is by fusion of multivesicular bodies with the plasmatic membrane. Exosomes released from placental cells have been found to be regulated by oxygen tension and glucose concentration. Furthermore, maternal exosomes have the ability to stimulate cytokine release from endothelial cells. In this review, we will discuss the role of EVs during fetal-maternal communication during gestation with a special emphasis on exosomes., (Copyright © 2016. Published by Elsevier Ltd.)

Our understanding of how cells communicate has undergone a paradigm shift since the recent recognition of the role of exosomes in intercellular signaling. In this study, we investigated whether oxygen tension alters the exosome release and miRNA profile from extravillous trophoblast (EVT) cells, modifying their bioactivity on endothelial cells (EC). Furthermore, we have established the exosomal miRNA profile at early gestation in women who develop pre-eclampsia (PE) and spontaneous preterm birth (SPTB). HTR-8/SVneo cells were used as an EVT model. The effect of oxygen tension (i.e. 8% and 1% oxygen) on exosome release was quantified using nanocrystals (Qdot®) coupled to CD63 by fluorescence NTA. A real-time, live-cell imaging system (Incucyte™) was used to establish the effect of exosomes on EC. Plasma samples were obtained at early gestation (<18 weeks) and classified according to pregnancy outcomes. An Illumina TrueSeq Small RNA kit was used to construct a small RNA library from exosomal RNA obtained from EVT and plasma samples. The number of exosomes was significantly higher in EVT cultured under 1% compared to 8% oxygen. In total, 741 miRNA were identified in exosomes from EVT. Bioinformatic analysis revealed that these miRNA were associated with cell migration and cytokine production. Interestingly, exosomes isolated from EVT cultured at 8% oxygen increased EC migration, whilst exosomes cultured at 1% oxygen decreased EC migration. These changes were inversely proportional to TNF-α released from EC. Finally, we have identified a set of unique miRNAs in exosomes from EVT cultured at 1% oxygen and exosomes isolated from the circulation of mothers at early gestation, who later developed PE and SPTB. We suggest that aberrant exosomal signalling by placental cells is a common aetiological factor in pregnancy complications characterised by incomplete SpA remodeling and is therefore a clinically relevant biomarker of pregnancy complications.

Recent studies report that 35% of women are either overweight or obese at reproductive age. The placenta continuously releases exosomes across gestation and their concentration is higher in pregnancy complications. While there is considerable interest in elucidating the role of exosomes during gestation, important questions remain to be answered: i) Does maternal BMI affect the exosomal profile across gestation? and ii) What is the contribution of placenta-derived exosomes to the total number of exosomes present in maternal plasma across gestation? Plasma samples were classified according to the maternal BMI into three groups (n = 15 per group): Lean, overweight, and obese. Total exosomes and specific placenta-derived exosomes were determined by Nanoparticle Tracking Analysis (NanoSight™) using quantum dots coupled with CD63 or PLAP antibodies. The effect of exosomes on cytokine (IL-6, IL-8, IL-10 and TNF-α) release from endothelial cells was established by cytokine array analysis (Bioplex-200). The total number of exosomes present in maternal circulation was strongly correlated with maternal BMI. Between ∼12% and ∼25% of circulating exosomes in maternal blood are of placental origin during gestation, and the contribution of placental exosomes to the total exosomal population decreases with higher maternal BMI across gestation. Exosomes increase IL-6, IL-8 and TNF-α release from endothelial cells, an effect even higher when exosomes were isolated from obese women compared to lean and overweight. This study established that maternal BMI is a factor that explains a significant component of the variation in the exosomes data. Exosomes may contribute to the maternal systemic inflammation during pregnancy., (Copyright © 2016. Published by Elsevier Ltd.)