One of the standards for cancer treatment is cancer immunotherapy which treats both primary and metastasized tumors. Although cancer immunotherapeutics show better outcomes as compared with conventional approaches of cancer treatment, the currently used cancer immunotherapeutics have limited application in delivering cancer antigens to immune cells. Conversely, in solid tumors, tumor microenvironment suppresses the immune system leading to the evasion of anticancer immunity. Some promising attempts have been made to overcome these drawbacks by using different approaches, for instance, the use of biomaterial-based nanoparticles. Accordingly, various studies involving the application of nanoparticles in cancer immunotherapy have been discussed in this review article. This review not only describes the modes of cancer immunotherapy to reveal the importance of nanoparticles in this modality but also narrates nanoparticle-mediated delivery of cancer antigens and therapeutic supplements. Moreover, the impact of nanoparticles on the immunosuppressive behavior of tumor environment has been discussed. The last part of this review deals with cancer immunotherapy using a combination of traditional interventional oncology approach and image-guided local immunotherapy against cancer. According to recent studies, cancer therapy can potentially be improved through nanoparticle-based immunotherapy. In addition, drawbacks associated with the currently used cancer immunotherapeutics can be fixed by using nanoparticles. Cancer is one of the most lethal diseases and is causing thousands of deaths annually throughout the world . It is tCurrent research work is focused on the management of cancer immunotherapeutics' shortcomings, for instance, by using nanoparticles . NanoparCancer treatment using immunotherapeutics depends on three important factors. The first factor deals with an effective transfer of cancer antigens to immune cells, particularly APCs (antigen-presenting cells), such as dendritic cells. The induction of anticancer immune response after delivery of adjuvant and cancer antigen to immune cells is the second requirement for this treatment. The third factor involves the modulation of the IDTM to induce a response to the anticancer immunotherapeutics. These aims can be achieved by using nanoparticulate systems, which can be potentially utilized for the induction of immune response against cancer. This review article describes the current trends in cancer therapy using nanoparticles as immune-modifying systems.For the application of nanoparticles in the treatment of cancer, it is a prerequisite to comprehend the mechanistic aspects of cancer immunotherapy. The framework of cancer immunotherapy research depends on a cancer-immunity cycle  which inProinflammatory cells, for instance, M1-polarized macrophages possess the capability of killing tumor cells. The deceased cells produce various immunosuppressive factors such as IL-10 (interleukin-10) inducing repolarization of macrophages from M1 to M2 –20. In aDuring current years, several nanoparticle systems  have beeNanoparticles are produced through physical, biological, and chemical methods. Biological methods are mainly used for microorganism-assisted biogenesis of metallic nanoparticles such as gold nanoparticles . SeveralNanoparticles possess distinguished physicochemical properties including size, shape, and charge, which can be customized to achieve various therapeutic goals such as cancer immunotherapy . For exaA considerable development in the field of cancer immunotherapy has been introduced during the last few years. However, clinical trials of cancer vaccines could not receive significant success. In addition to several other factors, this unremarkable accomplishment could be due to the fact that traditional methods of drug delivery techniques were not safe. In recent years, new opportunities, especially nanoparticle-based modalities, have been explored for the treatment of cancer . ParticuThe induction of tumor immunity requires the effective transfer of tumor antigens to APCs. The researchers have introduced two important classes of antigens, i.e., TAAs (tumor-associated antigens) and TSAs . Although TAAs are mainly expressed on cancer cells, normal and differentiating cancer cells also contain TAA contents. Thus, an autoimmune reaction might be caused when these antigens are used as immunotherapeutic targets. Alternatively, the autoimmune problem is not observed in the case of TSAs, since they are expressed in cancer cells only. However, the human enzyme system easily degrades these innate tumor antigens. In addition, these antigens are less efficiently transferred to immune cells; thus, they are known as weak immunogenic species. Since secondary lymphoid organs primarily home the immune response, an effective anticancer immune response can only be initiated when the lymph nodes are efficiently accessed by tumor antigens. In view of that, a nanoparticle-mediated safe delivery of tumor antigens to lymph nodes has been extensively investigated . These sNanoparticle delivery to lymph nodes is delicately affected by several factors such as water solubility, shape, size, and surface charge of nanoparticles –56.HydroIn addition to size, particle shape also affects nanoparticle drainage from lymph nodes. Nanoparticles have been prepared in a variety of shapes such as spherical, discs, rods, and stars . HoweverFurthermore, transportation of antigen-loaded nanoparticles depends on their size. Nanoparticle size neither should be lesser than 5 nm  to prevent their leakage from the circulatory system nor greater than 100 nm (termed as large-size nanoparticles) to avoid their entrapment in ECM and lymph nodes. Nanoparticles having a size of approximately 5–100 nm (termed as medium size nanoparticles) exhibit a prolonged circulation time and can be used to target the lymphatic system. For instance, PPS (poly(propylene sulfide)) nanoparticles having a size range of 20-45 nm persisted in the lymphatic system for about five days . AdditioFurthermore, the nanoparticle surface charge not only influences the cellular internalization but also affects the immune response activation . In geneTherapeutic supplements (TS), also known as adjuvants, are used in combination with tumor antigens to enhance their mutagenicity. TS have a resemblance to pathogenic molecules which are identified by pattern recognition receptors (PRRs) –69. An eA recent study described the simultaneous delivery of tumor-specific antigens (TSAs) and TS using nanoliposomes  having aTumors can create immunosuppressive tumor microenvironment which can enhance cancer growth and metastasis. Thus, cancer can be potentially treated by immunomodulation of tumor microenvironment .One of the potential examples of immunosuppressive T cells is Tregs  which caβ and IL-10. In addition, TAMs produce inflammatory cytokines such as IL-6 leading to the suppression of anticancer immune responses. Thus, effective cancer immunotherapy requires targeting and killing TAMs in the tumor microenvironment utilizing surface-modified nanoparticles.Tumor microenvironment contains a high level of TAMs. These are the immune cells which generate an excess of immunoregulatory cytokines such as TGF- (transforming growth factor-) β which suppresses activation, maturation, and differentiation of immune cells. Therefore, an immune response in cancer might be induced through the suppression of the TGF-β in the tumor microenvironment. In a recent study, nanoparticles were prepared by the process of microencapsulation for the delivery of TGF-β inhibitors to the tumor microenvironment. It resulted in the induction of both innate and adaptive immune activities leading to the inhibition of tumor growth as well as an improvement in the survival of mice having metastatic melanoma.Hepatic, lung, and breast cancer exhibit overexpression of various cytokines including TGF-Tumor microenvironment of hepatic, gastrointestinal, and breast cancer contains high levels of tumor-suppressor cells such as MDSCs which generate various cytokines such as IL-10 for the activation of Tregs and inhibition of other immune cells. In this context, effective cancer immunotherapy requires MDSC elimination in the tumor microenvironment. Nanoparticle-mediated delivery of immunomodulators to the tumor microenvironment can be accomplished via active or passive transport. Thus, the ameliorated anticancer immune effect and the reduced undesired effects can be acquired through nanoparticle-mediated delivery of immunomodulators to the tumor microenvironment.The recent studies combined various therapeutic approaches  with nanotechnology to overcome the immunosuppressant microenvironment of tumor-facilitating effective treatment of tumor –82. The The hundreds of studies have reported the synthesis of nanoparticles for the treatment of cancer; however, the majority of the developed nanoparticulate systems could not be translated into clinical use. A review published in 2016 on the nanoparticle-based studies conducted during the last 10 years revealed the delivery of <1% of the intravenously administered dose to solid tumors . It coulInterventional radiology is a branch of interventional oncology which deals with the use of image guidance for the localized diagnosis and treatment of cancer using a minimum surgical procedure . AnticanNanoparticles have several versatile features which pave their use in the fabrication of various imaging agents. For instance, ferric oxide nanoparticles , 88 and The currently available anticancer immunotherapeutic agents are directly administered to the circulatory system of the patients which leads to low efficacy and high toxicity. For instance, a high dose of an immune checkpoint suppressor is required when it is administered as an intravenous infusion. However, a stronger anticancer T cell activity with a low risk of side effects can be induced through local administration of an immune checkpoint suppressor, even at low doses , 91. NonThus, the locally administered nanoparticles which have imaging characteristics and can exert effective immunotherapeutic effect against cancer have gained promising importance. Nanoparticles loaded with low-dose immunotherapeutics can be developed by combining traditional interventional oncology approach with image-guided local immunotherapy against cancer to safely target immunological organs or solid tumors. One of the important features of this modality is the use of imaging devices for the confirmation of immunotherapeutic delivery to the target area.In image-guided local immunotherapy, the disposition of immunomodulatory agents can be monitored by imaging the nanoparticles loaded with cancer immunotherapeutics such as cancer antigens, cytokines, and adoptive cell therapeutic moieties. Consequently, conventional anticancer therapies can be replaced with more efficacious cancer therapy comprising cancer immunotherapy, nanotechnology, and interventional oncology.The current research has revealed the application of biomaterial-based nanoparticles in the amelioration of anticancer immunity. Nanoparticles can improve antigen presentation via efficient delivery of cancer antigens and therapeutic supplements to APCs in immunological organs, for example, lymph nodes. Therefore, a vaccine-like prolonged and broader immune effect can be yielded by utilizing nanoparticle-loaded cancer immunotherapeutics as compared with free immunotherapeutic agents. For instance, neoantigens based on mRNA (mRNA-nAg) are less immunogenic but its translation in the cytoplasm can enhance T cell activity . HoweverThe abovestated literature reveals that the interdisciplinary research, especially the union of various biomedical approaches, has evolved into current cancer immunotherapy. However, the development of biomaterial-based anticancer immunotherapy requires a detailed knowledge of how biomaterials interact with the immune system. For cancer immunotherapy, nanoparticle development using biomaterials has played an important role in achieving therapeutic efficacy at comparatively low doses and avoiding toxicity. In short, cancer patient's life quality and span can be improved by developing cancer vaccines based on nanoparticles.


Similarities in offspring phenotype due to maternal under- or over-nutrition during gestation have been observed in studies conducted at University of Wyoming. In these studies, ewes were either nutrient-restricted (NR) from early to mid-gestation, or fed an obesogenic diet (MO) from preconception through term. Offspring necropsies occurred at mid-gestation, late-gestation, and after parturition. At mid gestation, body weights of NR fetuses were ~30% lighter than controls, whereas MO fetuses were ~30% heavier than those of controls. At birth, lambs born to NR, MO, and control ewes exhibited similar weights. This was a consequence of accelerated fetal growth rates in NR ewes, and reduced fetal growth rates in MO ewes in late gestation, when compared to their respective controls. These fetal growth patterns resulted in remarkably similar effects of increased susceptibility to obesity, cardiovascular disease, and glucose intolerance in offspring programmed mostly during fetal stages of development. These data provide evidence that maternal under- and over-nutrition similarly induce the development of the same cadre of physical and metabolic problems in postnatal life. Accumulating evidence indicates that maternal and neonatal nutrition may have long lasting effects on the development of metabolic syndrome, which is characterized by insulin resistance, type II diabetes, obesity, dyslipidemia, hypertension, and cardiovascular disease . ExposurThere are three distinct but closely interacting epigenetic mechanisms that can be influenced by nutritional factors. These include DNA methylation, histone modifications, and non-coding microRNAs, which together regulate the intensity and timing of gene expression during development ,5. DiscoMetabolic imprinting describes the adaptive metabolic processes of the developing fetus in response to nutritional challenges throughout gestation that can have lasting effects into adulthood . MechaniSeveral animal models have been used to demonstrate the epigenetic effects of maternal nutrition on early fetal development. The earliest models included mice with metastable epialleles. The term “metastable” refers to the labile nature of the epigenetic state of these alleles, while “epiallele” defines their potential to maintain epigenetic marks over multiple generations . These mvyA) [FuAxin) [vyA allele displays a range of coat colors from completely yellow to wild-type agouti [vyA mice, supplementation of methyl donors including folate during pregnancy increased DNA methylation of the agouti gene in the vyA offspring leading to a decrease in agouti expression and browning of the coat color [vyA locus of the agouti mice despite the fact that genistein is not a methyl donor. Interestingly, this genistein-induced hypermethylation protected the vyA offspring from obesity in adulthood. This observation provided a link between maternal nutrition and susceptibility to chronic disease in the vyA progeny.Two notable examples of these epialleles are the viable yellow agouti (Avy) ,17 and a[AxinFu) ,19 allelat color ,20. Lateat color  demonstrFuAxin) mice have a spectrum of tail phenotypes, from severely kinked to completely normal. The extent of the kink in the tail is inversely related to the degree of methylation at the epiallele [FuAxin locus. Similar to the vyA model, dietary methyl donor supplementation of female mice before and during pregnancy induced DNA hypermethylation, resulting in reduced tail kinking in the Fu/+Axin offspring [The axin-fused (piallele . The mutffspring . TogetheEarly epidemiological studies linked maternal nutrition with the etiology of chronic disease in offspring. More specifically, both maternal undernutrition ,23 and mThe “thrifty phenotype” hypothesis of Hales and Baker  proposesThis paradox about similarities in offspring phenotype due to fetal exposure to either maternal under- or over-nutrition during gestation can at best be answered by observations from studies conducted at University of Wyoming utilizing sheep models ,29,33,34At mid gestation, NR fetuses weighed ~30% less than their respective controls, whereas MO fetuses weighed ~30% more than control fetuses. However, birthweight did not differ between NR, MO, or controls. This observation was a result of accelerated NR fetal growth in the second half of gestation, but a reduced MO fetal growth over this period when compared to their respective controls .The accelerated growth of NR fetuses after re-alimentation to 100% of nutritional requirements at mid-gestation was attributed to significantly increased placental vascularity and nutrient transporter activity . In contWe can therefore conclude that fetuses of NR and MO ewes both experienced a period of nutrient deprivation in the first or second half of gestation, respectively. In either case, exposure to nutrient deprivation during fetal development leads to an adaptive reallocation of nutrients favoring the development of the organs most critical for sustaining life, and therefore the development of a thrifty phenotype. We have also observed decreased expression of β-cells in the fetal pancreas in both NR  and MO  fetuses,The embryo-fetal stage is also crucial for skeletal muscle development, and for adipose and connective tissue development. Considering that skeletal muscle is one of the largest organs in non-obese subjects and a major site of insulin- and exercise-stimulated glucose disposal, proper fetal skeletal muscle development is important for the metabolic health of the offspring. Our studies have shown that maternal nutrient restriction reduced the formation of secondary myofibers and the ratio of secondary to primary myofibers during fetal development , resultiAnother likely mechanism for the similar phenotypic programming in both nutritional models is hypercortisolemia . Recent Expanding on the previous studies, we have also shown that many indications of the metabolic syndrome are observed in second ,59 and tThe data reviewed above provide robust evidence that maternal malnutrition alters the phenotype of both prenatal and postnatal offspring. These data further support the concept that both maternal overnutrition and maternal undernutrition similarly alter offspring phenotype, resulting in predisposition to metabolic syndrome later in development. The observed phenotypic differences in the offspring are likely derived from epigenetic responses to the altered nutritional state during gestation, subsequent alterations in gene expression, and ultimately, the development of a thrifty phenotype. In both undernourished and over-nourished pregnancies, the thrifty phenotype develops in response to a period of reduced fetal growth, which is disadvantageous in the face of nutrient availability, or even excess nutrient availability postnatally .Although undernutrition during pregnancy remains a significant public health issue, there is rising concern regarding the adverse effects of over-nutrition during pregnancy. Rates of overweight and obese women entering pregnancy are continuously increasing , which i


Metal nanoparticles are of increasing interest with respect to radiosensitization. The physical mechanisms of dose enhancement from X-rays interacting with nanoparticles has been well described theoretically, however have been insufficient in adequately explaining radiobiological response. Further confounding experimental observations is examples of radioprotection. Consequently, other mechanisms have gained increasing attention, especially via enhanced production of reactive oxygen species (ROS) leading to chemical-based mechanisms. Despite the large number of variables differing between published studies, a consensus identifies ROS-related mechanisms as being of significant importance. Understanding the structure-function relationship in enhancing ROS generation will guide optimization of metal nanoparticle radiosensitisers with respect to maximizing oxidative damage to cancer cells. This review highlights the physico-chemical mechanisms involved in enhancing ROS, commonly used assays and experimental considerations, variables involved in enhancing ROS generation and damage to cells and identifies current gaps in the literature that deserve attention. ROS generation and the radiobiological effects are shown to be highly complex with respect to nanoparticle physico-chemical properties and their fate within cells. There are a number of potential biological targets impacted by enhancing, or scavenging, ROS which add significant complexity to directly linking specific nanoparticle properties to a macroscale radiobiological result. Radiation therapy is currently utilized in more than 50% of all cancer treatments and commonly used in conjunction with chemotherapy or surgery . AlthougIn radiation therapy, cellular damage is caused by both direct and indirect mechanisms. Direct damage occurs when incident photons or particles cleave DNA, leading to apoptosis or necrosis. Indirect damage is primarily caused by interactions of ionizing radiation with oxygen-containing molecules, generating a variety of reactive oxygen species (ROS), including radicals ,9,10,11.Metal nanoparticle-based radiosensitization has received increasingly greater attention in research agendas, literature and clinical use ,17,18,19Initially, the concept of metal nanoparticle radiosensitizers was based on physical interactions with ionizing radiation. During X-ray irradiation, photons interact with metal nanoparticles, resulting in primary and secondary physical processes, such as the photoelectric effect, Compton scattering, Auger electron emission, X-ray fluorescence and pair production, with varying cross-section dependencies on atomic numbers and/or X-ray energy . TheoretThe photoelectric effect exhibits a strong dependence on the energy of the exciting X-ray. However, in vitro studies have shown comparable radiosensitization with MeV X-rays compared to keV X-rays  and alsoA critical aspect of nanoparticle radiosensitization is the mechanism by which they promote the generation of reactive species, especially ROS. Production of ROS are likely to be dependent on many variables and characteristics of the metal nanoparticle, such as size, shape and surface chemistry. The exact mechanisms of ROS generation, and hence their optimization for therapeutic purposes, by ionizing radiation interacting with nanoparticles are yet to be fully elucidated. To address this knowledge gap, this review critically discusses the relevant literature with a focus on discussing the role of metal nanoparticles in altering ROS generation during irradiation, as well as the techniques for measuring ROS in these studies. The goal of this review is to improve understanding of physico-chemical-based mechanisms of radiosensitization and radioprotection in the context of cancer radiation therapy. The majority of studies reported in literature have been conducted in vitro. While in vivo there will be significantly more complex biological processes involved, the basic physical principals enhancing ROS will be maintained. Better understanding of the metal nanoparticle structure-function relationship in enhancing ROS generation will guide the development of more potent agents.The generally accepted target in radiation therapy is double strand cleavage of cellular DNA by direct or indirect mechanisms . The celRadiation therapy induces ROS generation in the cell and also alters membrane permeability ,29. WhilThe localization of the metal nanoparticles can potentially also dictate the solubility and stability of the nanoparticles due to pH changes. Intracellular organelles, such as endosomes and lysosomes, are more acidic and may cause instability of metal nanoparticles. Chen et al. proposed that their hafnium-doped hydroxyapatite nanoparticles are localized in or near these organelles and therefore, release hafnium ions into the mitochondrial membrane to generate further ROS due to acidic pH in the tumour cells .Increasing ROS in cells can lead to apoptosis via a number of mechanisms summarized in Radiation and radiation induced ROS leads to lipid peroxidation. This damage is associated with permeability of cell membrane and disruption of transport of molecules across the membrane ,39. The There has been an immense progress in information regarding the production and scavenging of the reactive oxygen species . However2O2 and water (H2O) facilitates transport of H2O2 via aquaporins across membranes n) nanoparticles and showed an increase in ROS scavenging over time and also with an increase in nanoparticle concentration with ESR spin trapping of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) hydroxyl adduct [Electron spin resonance (ESR) is an analytical technique to detect unpaired electrons and is utilized to measure ROS generation due to the technique’s ability to classify specific radicals . Free ral adduct . Yu et al adduct . We are A large number of metal nanoparticles have been used in radiosensitization studies. Changes in the metal, size, shape and surface functionalization likely play important roles in ROS generation and scavenging. Metals are chosen with respect to biocompatibility, low cytotoxicity or for synergistic abilities, such as gadolinium as a contrast agent for diagnostics . Metals Metals such as iron and gadolinium have also been of interest as radiosensitizers due to their dual use in providing imaging contrast in MRI ,137,138.4+ and Ce3+, displaying their catalase-like activity in less acidic environments, such as the cytoplasm [The focus in radiation studies with metal nanoparticles has typically been in radiosensitization but nanoparticle-based radioprotection has also garnered interest. Ceria nanoparticles have displayed antioxidant properties due to rapid changes in oxidation state between Ceytoplasm ,105,139.ytoplasm . This waytoplasm . Generalytoplasm ,142. FurNanoparticle size can impact the generation of intracellular ROS during irradiation in several ways. Firstly, size impacts cellular uptake and is influential on receptor mediated endocytosis, one of the primary mechanisms involved in uptake by cancer cells ,143. GreImportantly, metal nanoparticle size influences ROS generation. Misawa et al. synthesized citrate coated AuNPs of sizes between 5 and 250 nm in solution and demonstrated that ROS generation is inversely proportional to the diameter of the nanoparticle, indicating the importance of the surface area of the nanoparticle . With smIn summary, the size of the nanoparticle is important in balancing nanoparticle biological interactions and maximizing the internalized surface area of nanoparticles to catalyse the generation of ROS under irradiation or number of secondary electrons exiting the nanoparticle volume.Few studies have focused on the impact of metal nanoparticle shape on ROS generation. Spherical nanoparticles typically have a higher affinity for cellular uptake than other morphologies ,147,148.Modifying the nanoparticle’s chemical and physical structure also has implications on ROS generation and can be demonstrated by comparing different crystal structures of titanium dioxide. Anatase titanium dioxide generates ROS more readily than a rutile structure due to an increased surface area to volume ratio and stability ,119,149.A stable dispersion of metal nanoparticles is important for many biological applications and is dependent on nanoparticle shape and surface chemistry. While stable nanoparticles are preferential in biological studies due to biocompatibility , some stDissociation of metal ions after cell uptake can enhance radiosensitization ,115,133,Surface chemistry of metal nanoparticles and the surface interactions govern their physicochemical properties . Most stCoating nanoparticles with polymers increases stability, biocompatibility and subsequently lowers the cytotoxicity of the nanoparticle. Polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and polyglycerol are nanoparticle capping agents that aid in stability and can operate as binding sites for additional conjugates ,136. PEGSurface functionalization can be utilized to promote cellular uptake and determine nanoparticle sub-cellular localization. Targeting ligand and peptide conjugation promotes nanoparticle uptake  and radi2O2, leading to further ROS production [2O2. Transportation and diffusion of H2O2 molecules into the tumour cell environment catalyses the production of H2O2 and overall ROS in the system [Surface functionalization of nanoparticles can synergistically increase uptake and transport oxygen-based molecules for increased ROS generation. Nakayama et al. increased ROS generation with titanium peroxide nanoparticles coated with polyacrylic acid, speculating that the coating was being peroxidised by Hoduction . Morita e system .Use of chemotherapeutic drugs have been explored for application with nanoparticle radiosensitization and there are studies that have investigated ROS generation for synergistic enhancement ,156,157.Antioxidants modulate ROS present within the cells and can be an additional target for nanoparticle radiosensitization. Yong et al. utilized gadolinium and tungsten-based nanoparticles, conjugated with chitosan, to decrease the concentration of glutathione within cells. While gadolinium increased the levels of ROS via physical mechanisms, levels of glutathione were decreased in the cell by a redox reaction with tungsten ions. This decrease of glutathione minimized the antioxidant properties of the cancer cell and radiosensitization occurred . AdditioThese examples of literature highlight the importance of surface properties not only with respect to stability and cell uptake, but also their synergistic or antagonistic influence on mechanistic action .Within this review, metal nanoparticle-based influence on ROS concentrations have been shown to play roles in both radiosensitization and radioprotection. Many studies investigate the effects of the nanoparticle structure and surface functionalization for nanoparticle uptake and radiosensitization during radiation therapy. The focus on the role of ROS as an important and exploitable mechanism is steadily growing. There is great scope to fundamentally understand, and optimise, the nanoparticle structure-function relationship with respect to maximizing the effects of ROS generation in radiosensitization. Critical to achieving this is reliable and robust analytical methods. The most utilized fluorescent dye approaches lack specificity, real-time measurements and rely on convoluted mediatory processes which introduce artefacts during data acquisition and interpretation. Real-time, direct measurements of reactive species in biologically relevant environments, encompassing adsorbed biomolecules, pH ranges and redox conditions are highly desirable for translation of a lab-based optimized nanoparticle to providing therapeutic efficacy.Many different metal nanoparticles with different sizes, compositions and surface functionalization are utilized in radiosensitization studies. Because of these variables, it is difficult to compare and identify common underpinning mechanisms of ROS generation. Significant challenges exist even in comparing one nanoparticle formulation to another as cellular internalization and fate are highly heterogeneous within, and between, cell populations and types. Even if different cell populations have statistically comparable average uptake of nanoparticles, the degree of heterogeneity between cell populations can still be statistically different . There i


The Covid-19 pandemic affects maternal health both directly and indirectly, and direct and indirect effects are intertwined. To provide a comprehensive overview on this broad topic in a rapid format behooving an emergent pandemic we conducted a scoping review.A scoping review was conducted to compile evidence on direct and indirect impacts of the pandemic on maternal health and provide an overview of the most significant outcomes thus far. Working papers and news articles were considered appropriate evidence along with peer-reviewed publications in order to capture rapidly evolving updates. Literature in English published from January 1st to September 11 2020 was included if it pertained to the direct or indirect effects of the COVID-19 pandemic on the physical, mental, economic, or social health and wellbeing of pregnant people. Narrative descriptions were written about subject areas for which the authors found the most evidence.The search yielded 396 publications, of which 95 were included. Pregnant individuals were found to be at a heightened risk of more severe symptoms than people who are not pregnant. Intrauterine, vertical, and breastmilk transmission were unlikely. Labor, delivery, and breastfeeding guidelines for COVID-19 positive patients varied. Severe increases in maternal mental health issues, such as clinically relevant anxiety and depression, were reported. Domestic violence appeared to spike. Prenatal care visits decreased, healthcare infrastructure was strained, and potentially harmful policies implemented with little evidence. Women were more likely to lose their income due to the pandemic than men, and working mothers struggled with increased childcare demands.Pregnant women and mothers were not found to be at higher risk for COVID-19 infection than people who are not pregnant, however pregnant people with symptomatic COVID-19 may experience more adverse outcomes compared to non-pregnant people and seem to face disproportionate adverse socio-economic consequences. High income and low- and middle-income countries alike faced significant struggles. Further resources should be directed towards quality epidemiological studies.The Covid-19 pandemic impacts reproductive and perinatal health both directly through infection itself but also indirectly as a consequence of changes in health care, social policy, or social and economic circumstances. The direct and indirect consequences of COVID-19 on maternal health are intertwined. To provide a comprehensive overview on this broad topic we conducted a scoping review. Pregnant women who have symptomatic COVID-19 may experience more severe outcomes than people who are not pregnant. Intrauterine and breastmilk transmission, and the passage of the virus from mother to baby during delivery are unlikely. The guidelines for labor, delivery, and breastfeeding for COVID-19 positive patients vary, and this variability could create uncertainty and unnecessary harm. Prenatal care visits decreased, healthcare infrastructure was strained, and potentially harmful policies are implemented with little evidence in high and low/middle income countries. The social and economic impact of COVID-19 on maternal health is marked. A high frequency of maternal mental health problems, such as clinically relevant anxiety and depression, during the epidemic are reported in many countries. This likely reflects an increase in problems, but studies demonstrating a true change are lacking. Domestic violence appeared to spike. Women were more vulnerable to losing their income due to the pandemic than men, and working mothers struggled with increased childcare demands. We make several recommendations: more resources should be directed to epidemiological studies, health and social services for pregnant women and mothers should not be diminished, and more focus on maternal mental health during the epidemic is needed. COVID-19, first documented in Wuhan, China at the end of 2019 , there aThis scoping review followed the framework outlined by Arksey and O’Malley , in ordeHow has the COVID-19 pandemic directly and indirectly impacted maternal health globally?Literature published in English from January 1st, 2020 to September 11, 2020 was included in the search. The search strategy involved the algorithm used by the Maternal Health Task Force’s Buzz, a biweekly e-newsletter presenting current research relevant to maternal health. Hand searches were conducted in PubMed using MeSH terms  were also included if returned by the search terms. Case reports, case series, qualitative studies, systematic and scoping reviews, and meta-analyses were included. As some publications included were systematic or scoping reviews or meta-analyses, there was some duplication in data on which publications were based. The article containing the more complete description of the data was used for data charting. Sources were excluded if they consisted only of recommendations for future research. Predictive research was excluded if it consisted only of speculation referencing past epidemics but included if based on quantitative methods. News articles, reports, and other grey literature were included if they contained quantifiable evidence .After reading full texts and synthesizing relevant evidence, literature was organized thematically. Themes were discussed and decided upon by all four authors. Themes that reflected potential impacts of COVID-19, but for which no quantitative evidence existed were excluded from the review. Of 200 peer-reviewed articles, 129 were excluded; 7 did not pertain to maternal health or COVID-19, 3 were responses to articles, and 199 were commentaries, editorials, or practice guidelines which did not contain relevant evidence. Of 196 articles from the grey literature, 172 articles were excluded; 124 did not pertain to maternal health or COVID-19, and 48 did not contain objective information. See Fig. 71 peer-reviewed articles and 24 publications from the grey literature were included from the original search. Two peer-reviewed articles that contradicted earlier findings that were published after September 11, 2020 were added. Publications included represented a wide range of methodologies including case reports, case series, observational studies, letters to the editor, and news articles. The authors developed a rubric of major themes that arose in the literature and recorded standard information including location, sampling method, and size of sample, and key findings of each study  admission involving mechanical ventilation was seldom required . ResultsPublications including data from a variety of contexts and designs found that the most commonly reported adverse outcome was preterm delivery –13, 19; The literature on maternal–fetal transmission of SARS-CoV-2 is highly speculative and requires additional evidence to confirm postulated mechanisms of transmission. Thus far, studies do not support intrauterine infection with COVID-19 resulting from vertical transmission in pregnant individuals with clinically or microbiologically diagnosed cases of the virus during the third trimester , 26–28. Despite this, transmission of the virus through blood is questionable. Egloff et al. hypothesized that transcytosis (transcellular transport) of the virus, infected blood cell transport, and virus or infected cells in the cervicovaginal compartment were unlikely avenues for transmission in most pregnant women with COVID-19. According to these data, the maternal–fetal transmission risk is probably very low, possibly under 1% following maternal SARS-CoV-2 infection during pregnancy . Yet, itA few case series including an analysis of 108 births occurring in New York City, suggest no increased risk of infection for the neonate when birth occurs vaginally. Despite early reassuring evidence that there is no increased risk of infection for the neonate when birth occurs vaginally , clinicaEstimates of C-section rates among women infected with SARS-CoV-2 differed but suggest a potentially significant increase in operative delivery. A systematic review conducted by Della Gatta et al. reported that 90.2% of women diagnosed with COVID-19 delivered via C-section  A systemParticularly in the beginning of the pandemic, hospitals implemented policies regarding support persons and postpartum stays that isolated women during labor and delivery. A comprehensive review of care guidelines from international perinatal societies and institutions found that most either recommended no visitors or one asymptomatic support person, and expedited discharge was recommended by the American College of Obstetrics and Gynecology, the Catalan Health Service, and the Society for Maternal and Fetal Medicine . Given tThe possibility of transmission of novel coronavirus through breast milk is unclear. The published evidence on the presence of SARS-CoV-2 in breastmilk consisted of case reports and case series of postpartum women who tested positive for the coronavirus during pregnancy. Of milk samples collected from 37 women, the majority tested negative for SARS-CoV-2 , 47, 48,Dong et al. reported the presence of IgG and IgA SARS-CoV-2 antibodies in breast milk samples taken from a woman with a positive throat swab test for COVID-19 . This suPublic health and medical organizations released guidance regarding breastfeeding for mothers with confirmed SARS-CoV-2 infection that weighed infection risk with the known and documented benefits of breastfeeding and early bonding. The WHO and UNICEF recommended continued breastfeeding, rooming in, skin to skin contact, and kangaroo care utilizing infection control practices. Specifically, the “WHO recommends that mothers with suspected or confirmed COVID-19 should be encouraged to initiate or continue to breastfeed. Mothers should be counselled that the benefits of breastfeeding substantially outweigh the potential risks for transmission.” In contrast, the Centers for Disease Control and Prevention, while encouraging the continuation of breastfeeding in general, stated, “temporary separation of the newborn from a mother with confirmed or suspected COVID-19 should be strongly considered to reduce the risk of transmission to the neonate” .Pregnant women and new mothers are more likely to experience mental illness than non-pregnant individuals . SeveralThe pandemic significantly impacted maternal mental health. Feelings of anxiety and depression were associated with maternal fear of vertical transmission of the virus to their infants, limited accessibility of antenatal care resources, and lack of social support , 54; theDuring pregnancy, self-reported rates of clinically relevant anxiety and depressive symptoms were higher among pregnant women relative to their retrospectively self-assessed pre-pandemic levels and when compared to non-pregnant individuals in a multicenter cross-sectional study performed in China by Y. Wu et al. In the same study, thoughts of self-harm were also more frequent than before the pandemic . AdditioThe postpartum period was less well-studied than the intrapartum period. Several authors speculated that limited health resources and increased prevalence of home deliveries without trained obstetric clinicians contributed to depression and distress among all pregnant women and new mothers , 59. JunThe COVID-19 pandemic required postponement of many non “essential” health services to prevent transmission within clinics, which led to significant reductions in the obtention of antenatal and postnatal care. In the US, an online survey of 4451 pregnant women found nearly a third reported elevated levels of stress, with alterations to prenatal appointments cited as a major reason for this elevation. . A modelThis estimate was supported by countries’ changes in perinatal care guidelines . A consuA global, cross-sectional study of maternal and newborn health professionals by Semaan et al. found a significant reduction in antenatal care services utilized as clinics reduced hours, number of visitors permitted, and in-person visits during pregnancy . In someThe temporary closure of outpatient clinics during shelter at home orders left many women without access to time-sensitive maternal and reproductive health care, from routine gynecological checkups to prenatal care to abortion. Classifying abortion care as “non-essential” severely restricted access regionally or nationwide in many countries during periods of lockdown , 72. TheSemaan et al. revealed that many maternal and newborn healthcare providers worldwide did not receive training in COVID-19 from their health facility, and 53% of participants in LMICS and 31% in HICs did not feel knowledgeable in how to care for a COVID-19 maternity patient; 90% of participants reported higher stress levels . This laWhile some maternal deaths observed during the pandemic were directly caused by COVID-19, a significant portion may have been attributable to underlying factors. Using evidence from a case series of 20 COVID-19-related maternal deaths, Takemoto et al. proposed that inadequacy of the Brazilian healthcare system was responsible for Brazil’s high rate of maternal mortality . In BrazStudies in both Nepal and the United Kingdom of pregnant individuals found the incidences of stillbirth and neonatal mortality were significantly higher during the pandemic period than the pre-pandemic period. Those experiencing stillbirth and infant mortality did not show symptoms of COVID-19, suggesting these outcomes may instead be due to the reallocation of medical resources towards COVID-19 patients and the subsequent reduction in hospitalization for labor management and perinatal care visits , 80. LikThe long-term impacts of the COVID-19 pandemic on maternal health were yet to be determined, but modelling studies indicated potentially grim outcomes particularly for LMICs. Weak healthcare systems in these countries were unable to mount the necessary response to the pandemic, which allowed the virus to spread rapidly . The pubThe social distancing and lockdown measures of the COVID-19 pandemic caused significant consequences for business sectors where interactions between individuals were frequent and often unavoidable. Women were over-represented in these industries; data from the UK Labour Force Survey revealed that approximately 46% and 39% of working women and men, respectively, were employed in critical sectors, while 19% and 13%, respectively, were employed in locked-down sectors . Safety While working an essential job provided job security, it also increased the risk of SARS-CoV-2 transmission, particularly in the healthcare workforce, given the high contact nature of medical care, the higher risk individuals who sought it, and the lack of PPE many hospitals faced , 88. DatIn LMICs, the majority of employed women worked in the informal sector, where they did not have access to services such as paid sick leave, maternity leave, or unemployment benefits , 91. DatIn several but not all HICs, women were still more likely to become unemployed during the COVID-19 crisis. The U.S. Bureau of Labor Statistics reported that in April 2020 alone, women accounted for 55% of the 20.5 million jobs lost in America, and that job loss was more prevalent and occurred at a more rapid rate for women than men . A studyLockdown measures required individuals to stay inside for extended periods of time, and early data demonstrated notable spikes in domestic violence (DV). Police data were consulted as evidence of increased violence, and surges in DV cases were noted in several countries –101. In There is a lack of representative epidemiological data on increased DV, and the existing data did not specify if the victims were pregnant or mothers. The breadth of reported cases is alarming, and this increase in DV is expected to be detrimental to maternal health outcomes –107. TheThis study represents a comprehensive scoping review of the direct and indirect impacts of the COVID-19 pandemic on maternal health. By using broad search terms and inclusion criteria, we were able to review literature on social and economic impacts of the pandemic as well as the physical and mental health impacts. However, this study did not include literature in languages other than English, which likely skews results towards countries in which English is the primary language. It was difficult to locate published information on LMICs pertaining to maternal health. We attempted to mitigate this by including grey literature and news articles from a variety of sources. Finally, while a scoping review methodology allowed us to rapidly synthesize literature, it does not represent as rigorous a process as a systematic review or meta-analysis.While early results suggested otherwise, recent studies with large sample sizes utilizing control groups suggest that pregnant people experiencing symptoms of COVID-19 are at higher risk of adverse outcomes than those who are not pregnant , 18. AddTo date, studies of the effects of the COVID-19 pandemic have, perhaps understandably, given time constraints and availability of data, lacked rigorous methods. To adequately assess these effects, we require research that carefully controls for pre-COVID-19 levels of the different outcomes of interest  and population characteristics  to more validly assess time trends. While reducing the frequency of prenatal visits in high income countries (HIC) may not necessarily be associated with worse birth outcomes, reducing the basic antenatal care in low- and middle-income countries (LMIC) is likely to impact maternal and neonatal health , 111. CoThe Covid-19 pandemic has created a multitude of questions regarding the optimal policies to reduce the spread of SARS-Cov-2 while minimizing the unintended detrimental consequences to family wellbeing and gender equity. Salient among these are: in what circumstances should schools and daycares resume care and in what format? Which models of antenatal and delivery care produce optimal outcomes? Which economic relief policies protect gender equity in the workplace and family wellbeing? Heterogeneous and inconsistent application of policies and models for healthcare and childcare delivery both within and across countries, while potentially not ideal for pandemic response, provide a near-natural experiment that helps to explore these questions.At the same time, policies impacting pregnant and parenting people have been implemented with little evidence. Several of these policies have the potential to significantly harm pregnant individuals’ health and undermine their rights. Most concerning are those that limit emotional support during labor and delivery, mandate early infant separation, and shorten postpartum stays. While the clinical rationale behind high C-section rates among pregnant individuals diagnosed with Covid-19 are unclear, these rates are alarming given that no evidence exists that C-section delivery lowers risk of transmission of SARS-CoV-2 or improves maternal health , 112.These concerns lead us to provide several clear policy recommendations we believe either have sufficient evidence to merit implementation or must be pursued because of ethical and human rights considerations. The first two pertain to healthcare policy. Given the evidence on the paucity of severe outcomes from SARS-CoV-2 infection in newborns, we urge the CDC to align with the WHO’s strong recommendation to keep the mother/infant dyad together even if the mother has a confirmed infection of SARS-CoV-2. Precautions, of course, are warranted, but our opinion is that the overwhelming evidence behind the benefits of early bonding and breastfeeding outweigh the risk of infection in the newborn.Second, whenever possible, healthcare organizations should consider the mental health impacts of any policies implemented to reduce risk of transmission. Early and convincing evidence currently exists that maternal mental health issues have increased during the pandemic. Policies that limit or eliminate the ability to give birth with a support person present or that are likely to increase distress, potentially exacerbating underlying mental health issues, should be avoided. With many healthcare organizations shortening postpartum hospital stays or providing postpartum visits through telemedicine, there is also the risk that screening for postpartum depression or other mental health issues will be forgotten or glossed over. Healthcare providers should be vigilant of the increased mental health needs of their pregnant and parenting patients.Finally, daycare and school closures are causing incredible stress and destabilization to caregivers, especially women, who often bear the brunt of childcare duties. These closures along with other workplace related consequences of the pandemic pose a serious threat to gender equity in the workforce. Without serious mitigation through policy, this threat is potentially far-reaching. We strongly recommend that governments prioritize the resumption of schooling under safe conditions and childcare when easing shelter in place or other pandemic-related restrictions. Failure to do so is likely to worsen any short-term losses in women’s employment given women’s disproportionate burden of childcare, and to put vulnerable single-mother and low income households at risk of poverty and food insecurity.While rigorous studies have not yet been conducted, early evidence from this scoping review shows that many of the social and economic consequences of the COVID-19 crisis likely affect women more than men. The low risk of mother to child transmission in-utero or via breast milk is well documented. It seems that pregnancy may constitute a particularly vulnerable period for COVID-19, but this requires further confirmation through well designed and implemented research. An increased risk of distress and psychiatric problems during pregnancy and postnatally during the pandemic is likely, but also in this case high-quality evidence is lacking. Likewise, a rise in the prevalence of domestic violence is plausible and supported by several studies, but we need more representative data. Studies of maternal morbidity and mortality are also lacking. Rigorous epidemiological studies must document the health impact of infection with SARS-CoV-2 during pregnancy as well as the changes in health care service and accessibility and their impact on maternal health. This review, however, provides good evidence that mothers with children are more likely to suffer job and income losses during the pandemic than men and women without children. Single mothers in particular are likely to suffer from food insecurity. These socioeconomic consequences for women are similar across many high- and low-income countries.Additional file 1. Pubmed MeSH Terms Utilized for Peer-Reviewed Articles.


Oral contraceptives (OCs) containing estrogen and progesterone analogues are widely used amongst reproductive-aged women, but their neurocognitive impact is poorly understood. Preliminary studies suggest that OCs improve verbal memory and that OCs with greater androgenic activity may improve visuospatial ability. We sought to explore the cognitive impact of OCs by assessing performance of OC users at different stages of the OC cycle, and comparing this performance between users of different OC formulations according to known androgenic activity. We conducted a prospective, observational trial of OC users, evaluating cognitive performance with CogState software on two occasions: days 7–10 of active hormonal pill phase, and days 3–5 of the inactive pill phase . Thirty-five OC users  were assessed. Analysis by androgenic activity showed superior performance by users of androgenic OCs, as compared to anti-androgenic OCs, in visuospatial ability and facial affect discrimination tasks. A growing understanding of cognitive effects of OC progestin androgenicity may have implications in choice of OC formulation for individuals and in future OC development. Oral contraceptives (OCs) are the most commonly prescribed medication in women of reproductive age to avoid unintended pregnancies and to alleviate menstrual pain, premenstrual syndrome, acne, and heavy bleeding . The psyAn established body of research shows that estrogens, progesterones, and androgens can influence cognitive processes ,5,6,7, wAt the molecular level, established neuromodulatory, neuroprotective, and neuroproliferative effects of hormones both in vitro and in vivo provide potential mechanisms for such hormone-dependent effects on cognition ,7,21. A Combined oral contraceptive formulations generally follow a 28-day cycle of 21–24 ‘active’ pills containing synthetic analogues of estrogen and progesterone, followed by 4–7 days of hormone-free inactive pills leading to a withdrawal bleed resembling menstruation. Administration of exogenous estrogen and progestins provides negative feedback to the hypothalamic–pituitary–gonadal axis, leading to a downregulation of endogenous sex hormone availability in OC users. Refinements in OC formulation have led to the current diversity of OCs, with varied side-effect profiles partly relating to the androgenic activity of the progestin component . Most cuThe cognitive impact of OCs has been investigated by approximately 22 studies over the past 50 years of use, but recent systematic reviews by our group and others show that a consensus remains elusive ,28. IncoStudies investigating associations between OC use and visuospatial abilities have mixed results. Several studies have reported no differences in mental rotation task performance (in terms of accuracy) between OC users and naturally cycling females ,35,36, aPrevious research linking OC use to processing of social-emotional information has been mixed, although a recent review proposed that emotional processes are influenced by OC use . A smallOur study aimed to investigate the cognitive impact of OC androgenicity across a range of cognitive domains, including domains hypothesized to be sensitive to estrogens, progesterones, and androgens, such as verbal memory and visuospatial abilities. Given the preliminary evidence for a differential impact of OC androgenicity in visuospatial ability, we hypothesized that progestin androgenicity group differences would be observed in these domains. We hypothesized that differences may also be seen in other domains with known sex differences or menstrual cycle fluctuation, such as social-emotional ability. The underexplored effects of progestin androgenicity may help explain the controversy surrounding the cognitive impact of oral contraceptives to date.We conducted a prospective, observational trial of healthy female OC-users, evaluating cognitive performance on two occasions: days 7–10 of active hormonal pill phase and days 3–5 of the inactive phase . The project received ethics approval from the Alfred Hospital Ethics Committee (46-09) and Monash University Human Research Ethics Committee (CF09/1895-2009001079). Inclusion criteria included current OC use, age over 18 years, fluency in English, and the ability to provide informed consent and attend two face-to-face interviews. Exclusion criteria included menopause, pregnancy or breastfeeding within the past 12 months, medical contraindications to OC use , and any history of neurological or cognitive impairment. Of 79 volunteers who responded to study advertisements, 21 declined to participate, 20 were excluded . Thirty-eight participants entered the study, three of whom withdrew prior to completion.Following written informed consent, demographic information was collected, including age, body mass index (BMI), ethnicity, handedness, education, and income; collected information about OC use included duration, adherence, and rates of adverse effects. Evaluation of premenstrual symptom burden was assessed using the Menstrual Distress Questionnaire . Mood waCognitive testing was performed using ‘CogState Research’ software . CogState has been validated in healthy populations ,50 and sParticipants were presented the program on a MacBook laptop computer. Completion of the battery took approximately 45 min and included assessment of verbal memory and recall, visual memory and recall, attention, executive function, psychomotor speed, and social-emotional ability via facial affect recognition, as summarized in OCs were categorized according to androgenic or anti-androgenic activity based on classifications established in current literature . Order oThe ‘inactive’ interview was arranged to coincide with the withdrawal bleed, days 1–3 of menstrual cycle, typically days 3–5 of inactive pill intake, with the exception of two participants taking Zoely and Qlaira who were testing during their shorter inactive pill window. This enabled maximum washout period while maintaining endogenous hormone suppression. The ‘active’ interview was timed to coincide with days 14–16 of the menstrual cycle, following continuous administration of at least seven days of active pills. There was a two-week interval between sessions. If a participant was unavailable to complete the second interview two weeks after the first, the follow-up interview was delayed until the subsequent menstrual cycle, which occurred for nine participants .Interviews were conducted in a private room to ensure confidentiality and minimize distraction. The two interviews were conducted at a similar time of day to eliminate the potential impact of diurnal variation. Participants were instructed to adhere to their normal dietary intake during the study period, including their typical pattern of caffeine and alcohol consumption. All participants confirmed they were not intoxicated at the time of testing.Statistical analyses: Variables OC class (anti-androgenic vs. androgenic) and pill phase (active vs. inactive) were factors. The dependent variables were cognitive task scores generated by the CogState program  method.In addition, further exploratory analysis was performed to determine the impact of other variables  on cognitive performance in the form of correlations across the cohort as a whole and separately within each progestin group.2. Twenty-five participants racially identified as white, with the remaining ten of mixed or Asian/Indian ethnicity. The majority were university students (91%). Our final sample included 35 females with mean age 22.9 years and mean BMI 21.31 kg/mComparable numbers of participants were taking ‘androgenic’ (first and second generation) OC formulations as were taking ‘anti-androgenic’ (third and fourth generation) brands, 18 and 17 women, respectively . Androgep = 0.04). Similarly, there was evidence against the null hypothesis that social-emotional task accuracy proportions were equal for both classes (adjusted p = 0.04), with the ratio (accuracy proportion) for anti-androgenic pill class participants being exp (−0.6346) *100% = 53% (less) than for the androgenic class participants. p-values for verbal, executive function, and psychomotor tasks support the conclusion there was weak or no evidence against the respective null hypotheses of no differences between the two pill classes. The one- and two-back task scores were not fitted in the random effects model because the algorithm failed to obtain the minimum variance quadratic unbiased estimates as starting values for the covariance parameters. Nevertheless, The adjusted The key finding from this study was a significant difference in visuospatial and social-emotional performance in androgenic compared to anti-androgenic OC users. We did not observe differences between active and inactive pill phases in any cognitive domain.The observation of improved visuospatial performance in users of OCs containing androgenic progestins throughout the cycle confirms and expands previous studies ,37. Our In addition, users of androgenic OCs also performed more accurately than anti-androgenic OC users on the social-emotional task that assessed facial emotion recognition/discrimination. An effect of androgenicity on facial emotion processing is without precedent in the literature. Facial emotion recognition/processing has been associated with a female advantage , and a rResults in the domains of verbal learning and memory, attention, executive function, and psychomotor ability demonstrated no effect of OC androgenicity. This is in line with our hypotheses as well as an absence of previous research indicating that androgenicity might affect these cognitive processes.Limitations of our study included the lack of a control group of OC nonusers and the small sample size representing a limited subset of OC users in that all were tertiary-educated and therefore cognitively high-functioning. Our study design did not allow assessment of the effect of duration of OC use. The addition of serum hormone measurements and neuroimaging would have provided further insight.Future research in this field may look to appraise cognition both on and off OCs to compare function in the same individuals under endogenous and exogenous hormonal conditions and may include increased sample sizes to explore newer OC formulations containing estradiol and estradiol valerate. Research regarding the impact of duration of OC use may also be informative. Understanding cognitive effects of OCs and progestin androgenicity may have implications in choice of OC formulation for individual women and in future OC development, as well as contributing to the growing knowledge base linking sex hormones and cognition. We acknowledge that the cognitive changes we observed are likely to be clinically subtle; however, it remains possible that OC use may still have an impact on cognition for some women. The influence of exogenous hormones on cognition is an area of growing interest. The impact of OCs on cognitive performance is poorly understood among medical professionals and patients alike. As evidence accumulates, it is important to facilitate informed contraceptive decision-making.


It has been recognized that cytokinins are plant hormones that influence not only numerous aspects of plant growth, development and physiology, including cell division, chloroplast differentiation and delay of senescence but the interaction with other organisms, including pathogens. Cytokinins are not only produced by plants but are also by other prokaryotic and eukaryotic organism such as bacteria, fungi, microalgae and insects. Notably, cytokinins are produced both by pathogenic and also beneficial microbes and are known to induce resistance in plants against pathogen infections. In this review the contrasting role of cytokinin for the defence and susceptibility of plants against bacterial and fungal pathogen and pest insects is assessed. We also discuss the cross talk of cytokinins with other phytohormones and the underlying mechanism involved in enhancing plant immunity against pathogen infections and explore possible practical applications in crop plant production. Plant hormones (Phytohormones) are naturally occurring small organic molecules that affect numerous aspects of growth and differentiation in plants and are involved in alleviating different biotic and abiotic stresses . So far,Cytokinins (CKs) influence various traits of plant growth, development and physiology such as seed germination, apical dominance, flower and fruit development, leaf senescence and plant-pathogen-interactions etc. CKs are isoprenoid substituted adenines molecule. Isopentenyltransferases (IPTs) is the first enzyme involved in catalyzing isoprenoid to other various types of CKs including cis-zeatin (cZ), N6-(Δ2-isopentenyl)-adenine (iP), trans-zeatin (tZ), and dihydrozeatin (DZ) (10). In plants, tZ occur in the most abundant form. CKs are further metabolized and inactivated through conjugation to sugars or through degradation by CK oxidases (CKXs).The type and activity of CK molecules differ remarkably between different plant species and tissues, at different developmental stages and under various environmental conditions. CKs are not only produced by plants but are also produced by plant associated microorganism, microalgae and insects.Arabidopsis  and microalgae, CKs are also produced by plant pathogens like fungi , nematodArabidopsis with 1 μm of trans-zeatin , for which the CK receptors have very high affinity, in response to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. Transient overexpression of CK producing IPT genes in tobacco   . Accordiormation . Howeverefaciens .Ustilago maydis  of tRNA-IPT, produce less lesions than wild-type strain without exhibiting distinct growth and development deficits in phenotypic appearance of rice plants , phytohormone equilibrium, regulation of photosynthesis, and photoassimilate translocation. CKs produce by plants, well known for cell division, leaf longevity and nutrient mobilization  are consignaling . Differeignaling .Resource allocation in plants for growth and defence needs to be regulated efficiently . Recent Beneficial microbes are recognized to induce systemic resistance against herbivorous insects and prevention to different environmental stresses . Living Manduca sexta, the gypsy moth Lymantria dispar or the green peach aphid Myzus persicae  was shown on infected tissues of g larvae . Increasidaginis .It is known that production of CK by gall-producing bacteria and green island forming fungi, but localized delay of senescence and formation of stay green phenomena on insect-attacked leaves could be due to production of CK by insects . FindingWolbachia is inherently involved  (N. tabacum) are infected with tobacco mosaic virus (TMV), cucumber mosaic virus, potato virus X, and potato virus Y  . It is a virus Y . General virus Y .OsPR1b and PBZ1 (see Appendix), while application of either hormone alone did not show a meaningful increase in defence gene expression, nor did co-treatment with SA and several hormones (The SA-dependence of CK-induced immunity can support inducing activity of CK, in which exogenous application of CK show increased level of SA-dependent gene expression during pathogen infection . In ricehormones .Nicotiana attenuate (CK is expected to be a systemic signal shimmering nutrient availability based on positive interaction between CK levels and nitrogen status, and enhanced nitrogen availability caused in higher JA biosynthesis and also downstream inducible antiherbivore genes in ttenuate . CK and ttenuate .Arabidopsis infection by P. syringae pv. tomato DC3000 by repressing PR1. Whereas resistance and induction of PR1 was seen with elevated CK level (There is also antagonism between CK and Auxin in plant immune defence. Elevated level of Auxin enhances susceptibility of CK level . ReducedCK level . CK can CK level .The impact of the SA-JA/ET core defence signaling in plant-pathogen exposure has long been established. However, our understanding of the influence plant growth-promoting hormones like CK; exerts on modulating the central defence pathways is still lagging. A focus on this area of plant defence will reveal key biological inferences concerning the trade-off between defence and growth in plants.The use of macroalgae in fields as a bio-fertilizer is a well-known practice . CyanobaDurvillaea potatorum and Ascophyllum nodosum (Ocimum sanctum reported by foliear spray of liquid extracts containing CK from marine macro algae Sargassum wightii, Turbinaria ornata and Caulerpa racemosaon (Anabaena, Oscillatoria, Phormidium, Chroococcidiopsis and Synechosystis have been shown to CKs production (P. fluorescens G20-18 (Interestingly, many articles point out that microalgae have been shown to produce Phytohormones, including auxin, ABA, CK, ET, and GAs. The presence of CKs have been reported in the extracts of Ulva , Durvill nodosum  which st nodosum . Enhancecemosaon . And furoduction  whereas s G20-18 .After a direct role of the classical plant growth stimulating phytohormone CK in the activation of plant defence had been recognized in the early 2010s, the production of CK by beneficial microorganisms is being recognized as relevant and widespread for inter-kingdom signaling to increase the immunity of plants against pathogens and pests Figure 1via stimulation of sink metabolism (It is intriguing that beneficial microbes share different effects known to be stimulated by CKs, namely growth, abiotic stress tolerance and biocontrol. Thus it remains to be elucidated whether also other functions of beneficial microbes are actually mediated by microbial CK production. Thus the role of microbial CK production will have to be considered in the interaction of the root and shoot microbiome with plants and how the holobiont growth, physiology and abiotic and biotic stress resiliency is affected. Also at a mechanistic level there are still number of open questions. Since CKs are also contributing to resource allocation tabolism . The reltabolism . Also thtabolism . The lattabolism  will be Virtually nothing is known how the production of CKs in microorganisms is regulated in response to environmental stimuli or plant derived signals. Thus it remains to be elucidated whether the plant derived factors differentially affect CK production in beneficial versus pathogenic microorganisms and whether the interference with CK production in pathogens is part of the plant defence.The biocontrol ability of microbial derived CKs opens up promising applications in integrated crop plant protection based on biologicals. Notably the combination with other beneficial CKs effects, such as the improvement of abiotic stress tolerance, or of the CK producing microbes, such as the biofertilizer function of microalgae, seems to be attractive in environmentally friendly and sustainable approaches to reduce the use of chemical pesticides within climate change scenarios. The possible promising applications of CK producing microorganisms in crop plant management will have to be also considered in screening programs for new beneficial microbes or the composition of synthetic communities. In contrast to CK originated from beneficial microorganism source, CK synthesized by pathogenic organism have the opposite effect on plant growth and defence. However, further research is warranted to investigate the type and structure of CK molecules produced by both beneficial and pathogenic organisms to understand their plant-beneficial and plant detrimental mode of action.All authors contributed equally to the article. SA, MM, CP and TR reviewed the literature and jointly wrote the article. SA, MM and CP contributed to manuscript revision and editing. TR provided feedback and final proof reading. SA coordinated the submission.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Occupying the interface between host and environment, host-associated microbes play fundamental roles in nutrient absorption, essential metabolite synthesis, development of the immune system, defence against pathogens and pathogenesis. Microbiota composition and function is rather stable during adulthood, while it dramatically changes during early development, frailty and disease. Ageing is associated with progressive decrease of homeostasis, often resulting in disruption of the physiological balance between host and commensal microbes, ultimately leading to dysbiosis and host demise. Generally, high microbial diversity is associated with health and a youthful state, while low individual microbial diversity and larger inter-individual microbial diversity is associated with ageing and disease states. Different species are equipped with species-specific commensal, symbiotic and pathogenic microbial communities. How and whether the specific host–microbiota consortia co-evolved with host physiology to ensure homeostasis and promote individual fitness remains an open question. In this essay, we propose that the evolution of vertebrate-specific immune adaptations may have enabled the establishment of highly diverse, species-specific commensal microbial communities. We discuss how the maintenance of intact immune surveillance mechanisms, which allow discrimination between commensal and pathogenic bacteria, fail during ageing and lead to the onset of known ageing-related diseases. We discuss how host–microbiota interactions are key to maintaining homeostasis despite external perturbations, but also how they affect a range of host-specific ageing-related phenotypes.This article is part of the theme issue ‘The role of the microbiome in host evolution’. At the same time, the emergence of lymphocyte-based adaptive immunity was instrumental to the establishment of host-specific, highly complex commensal microbial communities. Whether also microbes that are part of commensal microbiota  co-evolved with the host is still an open question. Highly diverse microbial communities associated with vertebrate epithelia gave access to a staggeringly vast range of microbial metabolites and molecular intermediates, allowing for a significant upgrade of the biosynthetic pathways encoded by the host's genome alone. However, while the establishment of a complex microbiota composition led to the acquisition of a large set of significant advantages, it also came with new costs. Imbalance in the complex signalling pathways that regulate the adaptive immune system can lead to dysfunctional responses towards pathogens and commensals, ultimately resulting in disease and death. The significant changes in microbiota composition occurring during ageing could thus be a direct consequence of the long evolutionary history shared between vertebrates and their complex, species-specific microbial communities.2.Buchnera to synthesize essential amino acids, which are lacking in the sap that aphids feed on. In return, aphids provide a stable ecological niche to their bacterial partner. This partnership is obligate for either side, as it is necessary for reproduction and survival .–71.69–71Hydra [Drosophila, FoxO also regulates innate immunity and chronic FoxO activation (e.g. during ageing) is associated with deregulated immune function, disorganization of the fly gut epithelium (metaplasia) and bacterial dysbiosis [Inflammaging and altered microbiota communities are mechanistically connected and the accumulation of pathogenic bacteria can lead to chronic intestinal inflammation, as in ulcerative colitis . Loss ofHydra . In Drosysbiosis . Conversysbiosis . Similarysbiosis . Furtherysbiosis . Note, tysbiosis .5.The immune system helps maintain systemic homeostasis and healthy tissues by eliminating damaged, infected and senescent cells  and by hMany aspects of adaptive immunity are also affected during ageing. Loss of B cell diversity  and loweThe evolution of the adaptive immune system gave a formidable fitness advantage to early vertebrates, which could discriminate between self and non-self, effectively eliminating pathogens and parasites, becoming able to establish a diverse community of commensals. However, if the adaptive immune system provided vertebrates with the new opportunity to have access to the biochemical diversity of complex microbiota, it also came with the cost of a new range of homeostatic failure modalities, which we propose may define vertebrate-specific ageing dynamics.Owing to the access to clean water, vaccinations and antibiotics, infectious diseases are no more the leading causes of death in industrialized countries. However, still today, the elderly are more susceptible to infections compared to young-adult individuals . Immune Here, we propose that vertebrate-specific ageing dynamics depend in part on the complex mechanistic interplay between microbiota and adaptive immunity, which has a long evolutionary history. Indeed, the adaptive immune system actively shapes commensal microbiota, which in turn contribute to immune system development and maintenance. Emerging recent scientific evidence indicates how the microbiota plays a causal role during ageing. Transplanting microbiota from young-adults to middle-aged individuals extends lifespan in a short-lived vertebrate model system, showing that young-associated gut microbes have cumulatively a pro-biotic action . AnalogoSeveral open questions remain to be addressed. If microbiota causally affect the ageing process, do individual-specific ageing dynamics—e.g. higher or lower risk for ageing-related diseases—depend on individual microbiota composition? Can we adopt the microbiota as a diagnostic tool to predict individual disease risk? If each species has its own, species-specific microbiota—which result as a function of their habitat, lifestyle, evolutionary history and specific immune system function—does each species differ accordingly in its ageing-related pathologies? If commensal microbes can suppress immune responses and favour immune tolerance (e.g. via SCFA), can pathogens hijack commensal's molecular signalling to selfishly favour pathogenicity? How can we maintain host–microbiota balance over extended time and during immune ageing?Together, the evolution of multicellular hosts and their microbial partners has led to the emergence of astonishing biological innovations, including a sophisticated adaptive immune system, which led to the opportunity to access a novel metabolic space—provided to the host by its commensal microbes—but also resulted in new modalities of homeostatic failure, which possibly characterize vertebrate-specific ageing dynamics.


Leptospira can yield disease phenotypes that vary from asymptomatic shedding in reservoir hosts, to multi-organ failure in incidental hosts. Clinical symptoms of acute leptospirosis reflect the diverse range of pathogenic species and serovars that cause infection, the level of exposure, and the relationship of the pathogen with the given host. However, in all cases, pathogenic Leptospira are excreted into the environment via urine from reservoir hosts which are uniformly recognized as asymptomatic carriers. Therefore, the reservoir host serves as the cornerstone of persistent disease transmission. Although bacterin vaccines can be used to abate renal carriage and excretion in domestic animal species, there is an urgent need to advance our understanding of immune-mediated host–pathogen interactions that facilitate persistent asymptomatic carriage. This review summarizes the current understanding of host–pathogen interactions in the reservoir host and prioritizes research to unravel mechanisms that allow for colonization but not destruction of the host. This information is required to understand, and ultimately control, the transmission of pathogenic Leptospira.Leptospirosis is a devastating zoonotic disease affecting people and animals across the globe. Pathogenic leptospires are excreted in urine of reservoir hosts which directly or indirectly leads to continued disease transmission, via contact with mucous membranes or a breach of the skin barrier of another host. Human fatalities approach 60,000 deaths per annum; though most vertebrates are susceptible to leptospirosis, complex interactions between host species and serovars of  Global human incidence of acute leptospirosis is estimated at 1.03 million annual cases, with higher incidence in tropical regions and populations from urban slum environments . ClinicaLeptospira also complicate the extrapolation of distinct observations. The existence of both genetic and serologic classification schemes can add another level of complexity to interpretation of these observations. Individual Leptospira species are represented by multiple serogroups which in turn can include multiple serovars. In addition, certain serovars may also be represented by strains from numerous separate species. For example, serovar Hardjo can include both Leptospira borgpetersenii  and Leptospira interrogans , and both L. borgpetersenii and L. interrogans can belong to the same serogroups including Australis, Hebdomadis, Pyrogenes, and Sejroe , such as lipopolysaccharide (LPS) from Leptospira, with Nod-like or Toll-like receptors . TLR4 is regarded as the classic LPS receptor, however, leptospiral LPS is substantially less reactive than comparative Gram-negative bacterial LPS such as E. coli. TLRs are expressed on renal epithelial cells and can be activated by leptospiral outer membrane lipoproteins including LipL32  mice utilize only TLR4  showed distinct restriction fragment length patterns associated with the domestic host species from which isolates were collected . While emphasis is often placed on which serovars are important for inclusion in a vaccine for a designated animal species, the strain of Leptospira in a reservoir host, is successful colonization of the kidney while escaping a fully fledged immune response that could result in respective host pathology or pathogen clearance. Even upon initial infection, true reservoir hosts lack the fever, cytokine storms, innate immune signals, and other hallmarks of leptospirosis observed in incidental hosts. Antibody production may still be induced in reservoir hosts, but not necessarily. In cattle, there is ample evidence of culture positive animals that were seronegative by MAT (L. borgpetersenii (serovar Hardjo) also minimally produce Neutrophil Extracellular Traps (NET) compared to Escherichia coli and PMA controls (L. interrogans (serovar Copenhageni) challenged animals were nearly identical to the spleens on non-infected controls  and the brown rat (Rattus norvegicus) may inhabit slightly different ecological niches; the black rat can be found in rural farm settings and woodlands while the brown rat is more often identified in close proximity to high population human areas (Leptospira (Leptospira load in the kidney of the rat and the amount of leptospires shed in the urine (R. norvegicus), positive kidneys have average concentrations of 5.9 × 106 leptospires per mL compared to the averaged matched urine samples of 6.1 × 106 leptospires per mL  offer additional insights (L. interrogans (serovar Copenhageni) inbred rats present asymptomatically, but kidneys become colonized and leptospires are shed in urine by 3 weeks, through at least 8 weeks, post challenge. Inbred rats developed robust antibody responses to leptospiral antigens, positive MAT titers, and showed prominent B cell proliferation when stimulated with leptospiral outer membrane proteins , and Grippotyphosa (Leptospira kirschneri). However, this pentavalent combination was not protective for cows against challenge with serovar Hardjo (L. borgpetersenii), and still resulted in abortion, urinary shedding, and even calves born with Leptospira colonized kidneys (L. borgpetersenii) within a pentavalent vaccine also did not confer protection against the same challenge, despite higher agglutination titers in animals that received the Hardjo-Bovis type vaccine compared to those receiving a Hardjo-Prajitno type vaccine (L. interrogans) organisms included in the vaccine formation also failed to confer protection when challenged with Hardjo (L. borgpetersenii) (L. borgpetersenii) vaccine was shown to successfully protect cattle against kidney colonization and prevented urinary shedding from a Hardjo (L. borgpetersenii) challenge  . Howeverhallenge . This fuhallenge . Indeed,hallenge  and to phallenge , howeverin vitro exposure to L. kirschneri serovar Grippotyphosa, suggesting potential Th1 cross protection  injection, which is not indicative of any natural route of infection. In fact, recent research has highlighted differences in pathogen kinetics, bacterial burden, and colonization between IP and more natural routes of experimental challenge, such as oral mucosa in mice , in vivo, in the intraperitoneal space of rats identified differentially expressed genes and highlighted physiological aspects of host adaptation by leptospires relating to heme uptake and utilization, as well as novel non-coding candidate small regulatory RNA expression   . For insted rats .in vitro or DMC cultivated counterparts based on proteins expressed, but also differ by individual protein post-translational modification (PTM), including trimethyllysine and acetyllysine  for pathogenic leptospires in vitro, the generation time during renal colonization in vivo can be assumed to be much shorter given that naturally infected rats excrete on average 6.1 × 106 leptospires per ml of urine (in vitro, but also provide insight into the development of culture systems that are more closely aligned with the in vivo infection environment. For instance, recent developments in the field of media composition have allowed, for the first time, successful long-term culture of L. borgpetersenii at 37°C, which better represents the incubated environment of live host (Modeling the behavior of pathogenic leptospires in the laboratory can be inherently difficult given that of urine . Similarof urine . A betteive host .Utilizing the natural reservoir host provides an opportunity to directly address some of the largest gaps in current leptospirosis research, and also contribute to models of acute disease. Such models also provide the opportunity to address clinical cases whereby acute symptoms resolve to asymptomatic carriage. This is evident not only in animals, but also in humans. Case reports demonstrate the ability of dogs to persistently shed leptospires even after antibiotic treatment . Unique Leptospira and the wide range of zoonotic hosts makes complete disease eradication unrealistic. However, the use of reservoir hosts as animal models of persistent infection provide the potential for leptospirosis research to advance our understanding of disease pathogenesis, transmission dynamics, immune responses, immune escape by the pathogen, and Leptospira and host species interactions which are critical to understand in the context of zoonotic control.Studying reservoir host systems addresses the naturally occurring issues of persistence and transmission of disease. Currently available tools should be utilized to study in detail relevant and naturally occurring reservoir host/serovar relationships. The widespread nature of EP wrote the manuscript. JN contributed greatly to the content of the review and edited the manuscript. Both authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.