Investigation of the interface of fungal mycelium composite building materials by means of low-vacuum scanning electron microscopy

Low-vacuum scanning electron microscopy (low-vacuum SEM) is widely used for different applications, such as the investigation of noncoated specimen or the observation of biological materials, which are not stable to high vacuum. In this study, the combination of mineral building materials (concrete or clay plaster) with a biological composite (fungal mycelium composite) by using low-vacuum SEM was investigated. Fungal biotechnology is increasingly gaining prominence in addressing the challenges of sustainability transformation. The construction industry is one of the biggest contributors to the climate crises and, therefore, can highly profit from applications based on regenerative fungal materials. In this work, a fungal mycelium composite is used as alternative to conventional insulating materials like Styrofoam. However, to adapt bio-based products to the construction industry, investigations, optimisations and adaptations to existing solutions are needed. This paper examines the compatibility between fungal mycelium materials with mineral-based materials to demonstrate basic feasibility. For this purpose, fresh and hardened concrete specimens as well as clay plaster samples are combined with growing mycelium from the tinder fungus Fomes fomentarius. The contact zone between the mycelium composite and the mineral building materials is examined by scanning electron microscopy (SEM). The combination of these materials proves to be feasible in general. The use of hardened concrete or clay with living mycelium composite appears to be the favoured variant, as the hyphae can grow into the surface of the building material and thus a layered structure with a stable connection is formed. In order to work with the combination of low-density organic materials and higher-density inorganic materials simultaneously, low-vacuum SEM offers a suitable method to deliver results with reduced effort in preparation while maintaining high capture and magnification quality. Not only are image recordings possible with SE and BSE, but EDX measurements can also be carried out quickly without the influence of a coating. Depending on the signal used, as well as the magnification, image-recording strategies must be adapted. Especially when using SE, an image-integration method was used to reduce the build-up of point charges from the electron beam, which damages the mycelial hyphae. Additionally using different signals during image capture is recommended to confirm acquired information, avoiding misinterpretations.

Cannabis, Cannabinoids, and Stroke: Increased Risk or Potential for Protection-A Narrative Review

Worldwide, approximately 15 million people per year suffer from stroke. With about 5 million deaths, stroke is the second most common cause of death and a major cause of long-term disability. It is estimated that about 25% of people older than 85 years will develop stroke. Cannabis sativa and derived cannabinoids have been used for recreational and medical purposes for many centuries. However, due to the legal status in the past, research faced restrictions, and cannabis use was stigmatized for potential negative impacts on health. With the changes in legal status in many countries of the world, cannabis and cannabis-derived substances such as cannabinoids and terpenes have gained more interest in medical research. Several medical effects of cannabis have been scientifically proven, and potential risks identified. In the context of stroke, the role of cannabis is controversial. The negative impact of cannabis use on stroke has been reported through case reports and population-based studies. However, potential beneficial effects of specific cannabinoids are described in animal studies under certain conditions. In this narrative review, the existing body of evidence regarding the negative and positive impacts of cannabis use prior to stroke will be critically appraised.

Sea Cucumber and Blueberry Extracts Suppress Inflammation and Reduce Acute Lung Injury through the Regulation of NF-κB/MAPK/JNK Signaling Pathway in Lipopolysaccharide-Treated C57BL/6 Mice

Acute lung injury (ALI) represents a life-threatening condition with high morbidity and mortality despite modern mechanical ventilators and multiple pharmacological strategies. Therefore, there is a need to develop efficacious interventions with minimal side effects. The anti-inflammatory activities of sea cucumber (Cucumaria frondosa) and wild blueberry (Vaccinium angustifolium) extracts have been reported recently. However, their anti-inflammatory activities and the mechanism of action against ALI are not fully elucidated. Thus, the present study aims to understand the mechanism of the anti-inflammatory activity of sea cucumber and wild blueberry extracts in the context of ALI. Experimental ALI was induced via intranasal lipopolysaccharide (LPS) instillation in C57BL/6 mice and the anti-inflammatory properties were determined by cytokine analysis, histological examination, western blot, and qRT-PCR. The results showed that oral supplementation of sea cucumber extracts repressed nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, thereby downregulating the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF) in the lung tissue and in the plasma. Wild blueberry extracts also suppressed the expression of IL-4. Furthermore, the combination of sea cucumber and wild blueberry extracts restrained MAPK signaling pathways by prominent attenuation of phosphorylation of NF-κB, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) while the levels of pro-inflammatory cytokines were significantly suppressed. Moreover, there was a significant and synergistic reduction in varying degrees of ALI lesions such as distorted parenchyma, increased alveoli thickness, lymphocyte and neutrophil infiltrations, fibrin deposition, pulmonary emphysema, pneumonia, intra-alveolar hemorrhage, and edema. The anti-inflammatory effect of the combination of sea cucumber and wild blueberry extracts is associated with suppressing MAPK and NF-κB signaling pathways, thereby significantly reducing cytokine storm in LPS-induced experimental ALI.

Lower Urinary Tract Inflammation and Infection: Key Microbiological and Immunological Aspects

The urinary system, primarily responsible for the filtration of blood and waste, is affected by several infectious and inflammatory conditions. Focusing on the lower tract, this review outlines the physiological and immune landscape of the urethra and bladder, addressing key immunological and microbiological aspects of important infectious/inflammatory conditions. The conditions addressed include urethritis, interstitial cystitis/bladder pain syndrome, urinary tract infections, and urosepsis. Key aspects of each condition are addressed, including epidemiology, pathophysiology, and clinical considerations. Finally, therapeutic options are outlined, highlighting gaps in the knowledge and novel therapeutic approaches.

Cannabinoids and the Endocannabinoid System in Early SARS-CoV-2 Infection and Long COVID-19-A Scoping Review

Coronavirus disease-19 (COVID-19) is a highly contagious illness caused by the SARS-CoV-2 virus. The clinical presentation of COVID-19 is variable, often including symptoms such as fever, cough, headache, fatigue, and an altered sense of smell and taste. Recently, post-acute "long" COVID-19 has emerged as a concern, with symptoms persisting beyond the acute infection. Vaccinations remain one of the most effective preventative methods against severe COVID-19 outcomes and the development of long-term COVID-19. However, individuals with underlying health conditions may not mount an adequate protective response to COVID-19 vaccines, increasing the likelihood of severe symptoms, hospitalization, and the development of long-term COVID-19 in high-risk populations. This review explores the potential therapeutic role of cannabinoids in limiting the susceptibility and severity of infection, both pre- and post-SARS-CoV-19 infection. Early in the SARS-CoV-19 infection, cannabinoids have been shown to prevent viral entry, mitigate oxidative stress, and alleviate the associated cytokine storm. Post-SARS-CoV-2 infection, cannabinoids have shown promise in treating symptoms associated with post-acute long COVID-19, including depression, anxiety, post-traumatic stress injury, insomnia, pain, and decreased appetite. While current research primarily focuses on potential treatments for the acute phase of COVID-19, there is a gap in research addressing therapeutics for the early and post-infectious phases. This review highlights the potential for future research to bridge this gap by investigating cannabinoids and the endocannabinoid system as a potential treatment strategy for both early and post-SARS-CoV-19 infection.

Neuroprotection and Beyond: The Central Role of CB1 and CB2 Receptors in Stroke Recovery

The endocannabinoid system, with its intricate presence in numerous cells, tissues, and organs, offers a compelling avenue for therapeutic interventions. Central to this system are the cannabinoid receptors 1 and 2 (CB1R and CB2R), whose ubiquity can introduce complexities in targeted treatments due to their wide-ranging physiological influence. Injuries to the central nervous system (CNS), including strokes and traumatic brain injuries, induce localized pro-inflammatory immune responses, termed neuroinflammation. Research has shown that compensatory immunodepression usually follows, and these mechanisms might influence immunity, potentially affecting infection risks in patients. As traditional preventive treatments like antibiotics face challenges, the exploration of immunomodulatory therapies offers a promising alternative. This review delves into the potential neuroprotective roles of the cannabinoid receptors: CB1R's involvement in mitigating excitotoxicity and CB2R's dual role in promoting cell survival and anti-inflammatory responses. However, the potential of cannabinoids to reduce neuroinflammation must be weighed against the risk of exacerbating immunodepression. Though the endocannabinoid system promises numerous therapeutic benefits, understanding its multifaceted signaling mechanisms and outcomes remains a challenge.

The immune response to systemically administered endotoxin in the murine intestinal microcirculation under pentobarbital versus isoflurane anesthesia

BACKGROUND

Pentobarbital and isoflurane are commonly used veterinary anesthetics. Due to the dangers of overdose by repeat-bolus regimen of pentobarbital, isoflurane has been recommended. However, literature suggests isoflurane-induced inhibition of cytokine and adhesion molecule release, impacting leukocyte adhesion.

OBJECTIVE

This study aims to characterize the impacts of pentobarbital versus isoflurane on leukocyte interactions within the intestinal microcirculation with and without endotoxin challenge.

METHODS

Female BALB/c mice were subjected to pentobarbital or isoflurane (N = 20) and challenged with endotoxin or saline by intraperitoneal injection. The mice were kept under anesthesia for 2 hours. Fluorochromes, rhodamine-6 G and fluorescein isothiocyanate, were injected intravenously. To visualize leukocyte adhesion within the intestinal microcirculation, laparotomy and intravital microscopy was performed. Leukocyte rolling and adhesion was quantified offline in a blinded fashion.

RESULTS

Within collecting venules, leukocyte rolling and adhesion showed no significant differences between pentobarbital and isoflurane anesthesia under basal conditions. Endotoxin challenge caused a similar response in both anesthetic groups. Within postcapillary venules, no statistical differences between the two anesthetics were found for adhering leukocytes under basal conditions or following endotoxin challenge either. However, leukocyte rolling after LPS-challenge was significantly decreased in postcapillary venules during isoflurane anesthesia compared to pentobarbital anesthesia.

CONCLUSIONS

Isoflurane anesthesia showed only minor differences in the immune response to endotoxin within the intestinal microcirculation compared to pentobarbital anesthesia. Due to the superior safety profile of volatile anesthetics, immunological studies may choose isoflurane over pentobarbital as the veterinary anesthetic of choice.

Intravital Microscopy of Lipopolysaccharide-Induced Inflammatory Changes in Different Organ Systems-A Scoping Review

Intravital microscopy (IVM) is a powerful imaging tool that captures biological processes in real-time. IVM facilitates the observation of complex cellular interactions in vivo, where ex vivo and in vitro experiments lack the physiological environment. IVM has been used in a multitude of studies under healthy and pathological conditions in different organ systems. IVM has become essential in the characterization of the immune response through visualization of leukocyte-endothelial interactions and subsequent changes within the microcirculation. Lipopolysaccharide (LPS), a common inflammatory trigger, has been used to induce inflammatory changes in various studies utilizing IVM. In this review, we provide an overview of IVM imaging of LPS-induced inflammation in different models, such as the brain, intestines, bladder, and lungs.

Cannabidiol Reduces Systemic Immune Activation in Experimental Acute Lung Injury

Background: The underlying pathomechanism of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is the immune response to inflammation or infection within the pulmonary microcirculation. Systemic spread of pathogens, activated immune cells, and inflammatory mediators contributes significantly to mortality in patients with ARDS. Objective: The endogenous cannabinoid system is a major modulator of the immune response during inflammation and infection. Phytocannabinoids, such as cannabidiol (CBD), have shown promising anti-inflammatory effects in several pathologies. The overall objective of this study was to evaluate the effects of CBD on local and systemic inflammation in endotoxin-induced ALI in mice. Materials and Methods: ALI was induced by pulmonary endotoxin challenge. Four groups of male C57BL/6 mice were randomized in this study: control, ALI, ALI with CBD treatment, and control with CBD treatment. Analyses of local and systemic cytokine levels, lung histology, and leukocyte activation as visualized by intravital microscopy of the intestinal and pulmonary microcirculation were performed 6 h following intranasal endotoxin administration. Results: Pulmonary endotoxin challenge induced significant inflammation evidenced by local and systemic cytokine and chemokine release, lung histopathology, and leukocyte adhesion. Intraperitoneal CBD treatment resulted in a significant decrease in systemic inflammation as shown by reduced leukocyte adhesion in the intestinal microcirculation and reduced plasma cytokine and chemokine levels. Pulmonary chemokine levels were decreased, while pulmonary cytokine levels were unchanged. Surprisingly, the ALI score was slightly increased by CBD treatment in a manner driven by enhanced neutrophil infiltration of the alveoli. Conclusion: In this model of experimental ALI, CBD administration was associated with reduced systemic inflammation and heterogeneous effects on pulmonary inflammation. Future studies should explore the mechanisms involved as they relate to neutrophil infiltration and proinflammatory mediator production within the lungs.

[Small Tick - Big Danger]

INTRODUCTION

We report a 23-year-old patient who presented to the general practitioner due to persisting headache, fever, and vomiting. In the further course, a tetraparesis dominated on the right side, dysphagia and dysarthria occurred, and a general tonic-clonic seizure. Further examinations confirmed tick-borne encephalomyelitis as well as polyradiculitis. After two months of rehabilitation, neuropsychological as well as focal-neurological deficits persisted in the unvaccinated patient.

Iron Chelation as a Potential Therapeutic Approach in Acute Lung Injury

Acute lung injury (ALI) has been challenging health care systems since before the COVID-19 pandemic due to its morbidity, mortality, and length of hospital stay. In view of the complex pathogenesis of ALI, effective strategies for its prevention and treatment are still lacking. A growing body of evidence suggests that iron dysregulation is a common characteristic in many subtypes of ALI. On the one hand, iron is needed to produce reactive oxygen species (ROS) as part of the immune response to an infection; on the other hand, iron can accelerate the occurrence of ferroptosis and extend host cell damage. Iron chelation represents a novel therapeutic strategy for alleviating lung injury and improving the survival of patients with ALI. This article reviews the current knowledge of iron homeostasis, the role of iron in ALI development, and potential therapeutic targets.

Antibacterial and Analgesic Properties of Beta-Caryophyllene in a Murine Urinary Tract Infection Model

Beta-caryophyllene has demonstrated anti-inflammatory effects in a variety of conditions, including interstitial cystitis. These effects are mediated primarily via the activation of the cannabinoid type 2 receptor. Additional antibacterial properties have recently been suggested, leading to our investigation of the effects of beta-caryophyllene in a murine model of urinary tract infection (UTI). Female BALB/c mice were intravesically inoculated with uropathogenic Escherichia coli CFT073. The mice received either beta-caryophyllene, antibiotic treatment using fosfomycin, or combination therapy. After 6, 24, or 72 h, the mice were evaluated for bacterial burden in the bladder and changes in pain and behavioral responses using von Frey esthesiometry. In the 24 h model, the anti-inflammatory effects of beta-caryophyllene were also assessed using intravital microscopy. The mice established a robust UTI by 24 h. Altered behavioral responses persisted 72 h post infection. Treatment with beta-caryophyllene resulted in a significant reduction in the bacterial burden in urine and bladder tissues 24 h post UTI induction and significant improvements in behavioral responses and intravital microscopy parameters, representing reduced inflammation in the bladder. This study demonstrates the utility of beta-caryophyllene as a new adjunct therapy for the management of UTI.

Sex-based analysis of treatment responses in animal models of sepsis: a preclinical systematic review protocol

BACKGROUND

The importance of investigating sex- and gender-dependent differences has been recently emphasized by major funding agencies. Notably, the influence of biological sex on clinical outcomes in sepsis is unclear, and observational studies suffer from the effect of confounding factors. The controlled experimental environment afforded by preclinical studies allows for clarification and mechanistic evaluation of sex-dependent differences. We propose a systematic review to assess the impact of biological sex on baseline responses to disease induction as well as treatment responses in animal models of sepsis. Given the lack of guidance surrounding sex-based analyses in preclinical systematic reviews, careful consideration of various factors is needed to understand how best to conduct analyses and communicate findings.

METHODS

MEDLINE and Embase will be searched (2011-present) to identify preclinical studies of sepsis in which any intervention was administered and sex-stratified data reported. The primary outcome will be mortality. Secondary outcomes will include organ dysfunction, bacterial load, and IL-6 levels. Study selection will be conducted independently and in duplicate by two reviewers. Data extraction will be conducted by one reviewer and audited by a second independent reviewer. Data extracted from included studies will be pooled, and meta-analysis will be conducted using random effects modeling. Primary analyses will be stratified by animal age and will assess the impact of sex at the following time points: pre-intervention, in response to treatment, and post-intervention. Risk of bias will be assessed using the SYRCLE's risk-of-bias tool. Illustrative examples of potential methods to analyze sex-based differences are provided in this protocol.

DISCUSSION

Our systematic review will summarize the current state of knowledge on sex-dependent differences in sepsis. This will identify current knowledge gaps that future studies can address. Finally, this review will provide a framework for sex-based analysis in future preclinical systematic reviews.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022367726.

Dysregulated Iron Homeostasis as Common Disease Etiology and Promising Therapeutic Target

Iron is irreplaceably required for animal and human cells as it provides the activity center for a wide variety of essential enzymes needed for energy production, nucleic acid synthesis, carbon metabolism and cellular defense. However, iron is toxic when present in excess and its uptake and storage must, therefore, be tightly regulated to avoid damage. A growing body of evidence indicates that iron dysregulation leading to excess quantities of free reactive iron is responsible for a wide range of otherwise discrete diseases. Iron excess can promote proliferative diseases such as infections and cancer by supplying iron to pathogens or cancer cells. Toxicity from reactive iron plays roles in the pathogenesis of various metabolic, neurological and inflammatory diseases. Interestingly, a common underlying aspect of these conditions is availability of excess reactive iron. This underpinning aspect provides a potential new therapeutic avenue. Existing hematologically used iron chelators to take up excess iron have shown serious limitations for use but new purpose-designed chelators in development show promise for suppressing microbial pathogen and cancer cell growth, and also for relieving iron-induced toxicity in neurological and other diseases. Hepcidin and hepcidin agonists are also showing promise for relieving iron dysregulation. Harnessing iron-driven reactive oxygen species (ROS) generation with ferroptosis has shown promise for selective destruction of cancer cells. We review biological iron requirements, iron regulation and the nature of iron dysregulation in various diseases. Current results pertaining to potential new therapies are also reviewed.

The paradox of the life sciences: How to address climate change in the lab: How to address climate change in the lab

Addressing climate change and sustainability starts with individuals and moves up to institutional change. Here is what we as scientists in the life sciences can do to enact change.

Current approaches for the treatment of ketamine-induced cystitis

AIMS

Ketamine is a dissociative anesthetic, historically used in a clinical setting for the induction and maintenance of anesthesia. Ketamine usage can produce undesirable psychological manifestations including hallucinations and long-term psychotomimetic effects. As a results of its fast onset and short period of action, ketamine is widely used as a recreational drug. Chronic abuse of ketamine can lead to significant urinary system complications including ketamine-induced cystitis (KIC). Common side effects of chronic ketamine abuse are urinary pain and discomfort and decreased bladder compliance and voiding pressure. Cessation of ketamine use is associated with improvement of symptoms however the exact pathophysiology of KIC remains unknown, complicating the ability of clinicians to treat this condition.

METHOD

A literature search was performed using the National Center for Biotechnology Information (NCBI) Pubmed database up to May 2021.

RESULTS

Animal models of KIC are necessary to further our understanding of KIC pathophysiology and explore potential treatment options. In all cases, cessation of ketamine use is the first line of treatment and is most effective in managing KIC. In addition to cessation, treatment plans must be tailored to the individual, based on the severity of symptoms and disease progression, and include options such as: oral anti-inflammatories, intravesical treatment and in the most severe cases, surgical intervention.

CONCLUSION

KIC is a painful condition that currently lacks standardized treatment methods. Both animal models of KIC and clinical trials to further elucidate the mechanism of KIC pathophysiology must be explored to create targeted treatment plans.

Purified complement C3b triggers phagocytosis and activation of human neutrophils via complement receptor 1

The complement system provides vital immune protection against infectious agents by labeling them with complement fragments that enhance phagocytosis by immune cells. Many details of complement-mediated phagocytosis remain elusive, partly because it is difficult to study the role of individual complement proteins on target surfaces. Here, we employ serum-free methods to couple purified complement C3b onto E. coli bacteria and beads and then expose human neutrophils to these C3b-coated targets. We examine the neutrophil response using a combination of flow cytometry, confocal microscopy, luminometry, single-live-cell/single-target manipulation, and dynamic analysis of neutrophil spreading on opsonin-coated surfaces. We show that purified C3b can potently trigger phagocytosis and killing of bacterial cells via Complement receptor 1. Comparison of neutrophil phagocytosis of C3b- versus antibody-coated beads with single-bead/single-target analysis exposes a similar cell morphology during engulfment. However, bulk phagocytosis assays of C3b-beads combined with DNA-based quenching reveal that these are poorly internalized compared to their IgG1 counterparts. Similarly, neutrophils spread slower on C3b-coated compared to IgG-coated surfaces. These observations support the requirement of multiple stimulations for efficient C3b-mediated uptake. Together, our results establish the existence of a direct pathway of phagocytic uptake of C3b-coated targets and present methodologies to study this process.

Protection of the endothelium and endothelial glycocalyx by hydrogen against ischaemia-reperfusion injury in a porcine model of cardiac arrest

BACKGROUND

Hydrogen is a potent antioxidant agent that can easily be administered by inhalation. The aim of the study was to evaluate whether hydrogen protects the endothelial glycocalyx layer after successful cardiopulmonary resuscitation (CPR).

METHODS

Fourteen anesthetized pigs underwent CPR after induced ventricular fibrillation. During CPR and return of spontaneous circulation, 2% hydrogen gas was administered to seven pigs (hydrogen group) and seven constituted a control group. Biochemistry and sublingual microcirculation were assessed at baseline, during CPR, at the 15th, 30th, 60th, 120th minute.

RESULTS

All seven subjects from the hydrogen group and six subjects in the control group were successfully resuscitated after 6-10 minutes. At baseline, there were no statistically significant differences in examined variables. After the CPR, blood pH, base excess, and lactate showed significantly smaller deterioration in the hydrogen group than in the control group. By contrast, plasma syndecan-1 and the measured variables obtained via sublingual microcirculation did not change after the CPR; and were virtually identical between the two groups.

CONCLUSION

In pigs, hydrogen gas inhalation during CPR and post-resuscitation care was associated with less pronounced metabolic acidosis compared to controls. However, we could not find evidence of injury to the endothelium or glycocalyx in any studied groups.

Cannabinoid effects in the microvasculature - CB, or not CB? That is the question! A mini-review

Cannabinoids play critical roles in human pathophysiology through the cannabinoid (CB) receptors and non-CB receptors on variety of cells, tissues, and organs. Microvasculature with the inside bloodstream containing the plasmatic and cellular components exerts multiple functions in maintaining tissue and organ physiology through microcirculation. This review focusses on the impact of cannabinoids on the microvasculature, including mechanisms mediated by both CB receptor-related pathways and CB receptor-independent pathways.

Selective CB2 Receptor Agonist, HU-308, Reduces Systemic Inflammation in Endotoxin Model of Pneumonia-Induced Acute Lung Injury

Acute respiratory distress syndrome (ARDS) and sepsis are risk factors contributing to mortality in patients with pneumonia. In ARDS, also termed acute lung injury (ALI), pulmonary immune responses lead to excessive pro-inflammatory cytokine release and aberrant alveolar neutrophil infiltration. Systemic spread of cytokines is associated with systemic complications including sepsis, multi-organ failure, and death. Thus, dampening pro-inflammatory cytokine release is a viable strategy to improve outcome. Activation of cannabinoid type II receptor (CB₂) has been shown to reduce cytokine release in various in vivo and in vitro studies. Herein, we investigated the effect of HU-308, a specific CB₂ agonist, on systemic and pulmonary inflammation in a model of pneumonia-induced ALI. C57Bl/6 mice received intranasal endotoxin or saline, followed by intravenous HU-308, dexamethasone, or vehicle. ALI was scored by histology and plasma levels of select inflammatory mediators were assessed by Luminex assay. Intravital microscopy (IVM) was performed to assess leukocyte adhesion and capillary perfusion in intestinal and pulmonary microcirculation. HU-308 and dexamethasone attenuated LPS-induced cytokine release and intestinal microcirculatory impairment. HU-308 modestly reduced ALI score, while dexamethasone abolished it. These results suggest administration of HU-308 can reduce systemic inflammation without suppressing pulmonary immune response in pneumonia-induced ALI and systemic inflammation.

A limit on variations in the fine-structure constant from spectra of nearby Sun-like stars

The fine structure constant α sets the strength of the electromagnetic force. The Standard Model of particle physics provides no explanation for its value, which could potentially vary. The wavelengths of stellar absorption lines depend on α but are subject to systematic effects owing to astrophysical processes in stellar atmospheres. We measured precise line wavelengths from observations of 17 stars, selected to have almost identical atmospheric properties to those of the Sun (solar twins), which reduces those systematic effects. We found that α varies by ≲ 50 parts per billion within 50 parsecs from Earth. Combining the results from all 17 stars provides an empirical local reference for stellar measurements of α, with an ensemble precision of 12 parts per billion.

Antiviral and Anti-Inflammatory Plant-Derived Bioactive Compounds and Their Potential Use in the Treatment of COVID-19-Related Pathologies

The highly contagious coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared a global pandemic and public health emergency as it has taken the lives of over 5.7 million in more than 180 different countries. This disease is characterized by respiratory tract symptoms, such as dry cough and shortness of breath, as well as other symptoms, including fever, chills, and fatigue. COVID-19 is also characterized by the excessive release of cytokines causing inflammatory injury to the lungs and other organs. It is advised to undergo precautionary measures, such as vaccination, social distancing, use of masks, hygiene, and a healthy diet. This review is aimed at summarizing the pathophysiology of COVID-19 and potential biologically active compounds (bioactive) found in plants and plant food. We conclude that many plant food bioactive compounds exhibit antiviral and anti-inflammatory properties and support in attenuating organ damage due to reduced cytokine release and improving the recovery process from COVID-19 infection.

Antibacterial Effects of Phytocannabinoids

Antibiotics are used as the first line of treatment for bacterial infections. However, antibiotic resistance poses a significant threat to the future of antibiotics, resulting in increased medical costs, hospital stays, and mortality. New resistance mechanisms are emerging and spreading globally, impeding the success of antibiotics in treating common infectious diseases. Recently, phytocannabinoids have been shown to possess antimicrobial activity on both Gram-negative and Gram-positive bacteria. The therapeutic use of phytocannabinoids presents a unique mechanism of action to overcome existing antibiotic resistance. Future research must be carried out on phytocannabinoids as potential therapeutic agents used as novel treatments against resistant strains of microbes.

Iron Overload and Breast Cancer: Iron Chelation as a Potential Therapeutic Approach

Breast cancer has historically been one of the leading causes of death for women worldwide. As of 2020, breast cancer was reported to have overtaken lung cancer as the most common type of cancer globally, representing an estimated 11.3% of all cancer diagnoses. A multidisciplinary approach is taken for the diagnosis and treatment of breast cancer that includes conventional and targeted treatments. However, current therapeutic approaches to treating breast cancer have limitations, necessitating the search for new treatment options. Cancer cells require adequate iron for their continuous and rapid proliferation. Excess iron saturates the iron-binding capacity of transferrin, resulting in non-transferrin-bound iron (NTBI) that can catalyze free-radical reactions and may lead to oxidant-mediated breast carcinogenesis. Moreover, excess iron and the disruption of iron metabolism by local estrogen in the breast leads to the generation of reactive oxygen species (ROS). Therefore, iron concentration reduction using an iron chelator can be a novel therapeutic strategy for countering breast cancer development and progression. This review focuses on the use of iron chelators to deplete iron levels in tumor cells, specifically in the breast, thereby preventing the generation of free radicals. The inhibition of DNA synthesis and promotion of cancer cell apoptosis are the targets of breast cancer treatment, which can be achieved by restricting the iron environment in the body. We hypothesize that the usage of iron chelators has the therapeutic potential to control intracellular iron levels and inhibit the breast tumor growth. In clinical settings, iron chelators can be used to reduce cancer cell growth and thus reduce the morbidity and mortality in breast cancer patients.

Anti-Inflammatory Effects of the Iron Chelator, DIBI, in Experimental Acute Lung Injury

Iron plays a critical role in the immune response to inflammation and infection due to its role in the catalysis of reactive oxygen species (ROS) through the Haber-Weiss and Fenton reactions. However, ROS overproduction can be harmful and damage healthy cells. Therefore, iron chelation represents an innovative pharmacological approach to limit excess ROS formation and the related pro-inflammatory mediator cascades. The present study was designed to investigate the impact of the iron chelator, DIBI, in an experimental model of LPS-induced acute lung injury (ALI). DIBI was administered intraperitoneally in the early and later stages of lung inflammation as determined by histopathological evaluation. We found that lung tissues showed significant injury, as well as increased NF-κB p65 activation and significantly elevated levels of various inflammatory mediators (LIX, CXCL2, CCL5, CXCL10, IL-1𝛽, IL-6) 4 h post ALI induction by LPS. Mice treated with DIBI (80 mg/kg) in the early stages (0 to 2 h) after LPS administration demonstrated a significant reduction of the histopathological damage score, reduced levels of NF-κB p65 activation, and reduced levels of inflammatory mediators. Intravital microscopy of the pulmonary microcirculation also showed a reduced number of adhering leukocytes and improved capillary perfusion with DIBI administration. Our findings support the conclusion that the iron chelator, DIBI, has beneficial anti-inflammatory effects in experimental ALI.

The Endocannabinoid System: A Potential Therapeutic Target for Coagulopathies

Abnormal blood coagulation or coagulopathy is a common manifestation of many pathological conditions. It occurs when there is an imbalance between the activities of the coagulation system and the fibrinolytic system, leading to excessive or impaired intravascular blood clot formation, which can disturb blood flow causing ischemia or hemorrhage in the affected tissues. A growing body of evidence has demonstrated blood coagulation abnormalities in association with cannabinoid use, suggesting the involvement of the endogenous cannabinoid system (ECS) in modulating blood coagulation. However, the evidence in the literature has been controversial on whether cannabinoids promote or inhibit blood coagulation. The ECS has been extensively studied in recent years for its potential as a therapeutic target for many diseases. This review provides a brief introduction to the ECS and discusses the reported anticoagulatory and procoagulatory effects of various cannabinoids, highlighting some possible mechanisms that might underlie the observed effects. Understanding the coagulatory effects of cannabinoids and the interaction between the coagulation system and the ECS is vital for developing novel therapeutics for coagulopathies.

Assessing the impact of predatory journals on policy and guidance documents: a cross-sectional study protocol

INTRODUCTION

Many predatory journals fail to follow best publication practices. Studies assessing the impact of predatory journals have focused on how these articles are cited in reputable academic journals. However, it is possible that research from predatory journals is cited beyond the academic literature in policy documents and guidelines. Given that research used to inform public policy or government guidelines has the potential for widespread impact, we will examine whether predatory journals have penetrated public policy.

METHODS AND ANALYSIS

This is a descriptive study with no hypothesis testing. Policy documents that cite work from the known predatory publisher OMICS will be downloaded from the Overton database. Overton collects policy documents from over 1200 sources worldwide. Policy documents will be evaluated to determine how the predatory journal article is used. We will also extract epidemiological details of the policy documents, including: who funded their development, the discipline the work is relevant to and the name of the organisations producing the policy. The record of scholarly citations of the identified predatory articles will also be examined. Findings will be reported with descriptive statistics using counts and percentages.

ETHICS AND DISSEMINATION

No ethical approval was required for this study since it does not involve human or animal research. Study findings will be discussed at workshops on journalology and predatory publishing and will be disseminated through preprint, peer-reviewed literature and conference presentations.

Endothelial glycocalyx damage in patients with severe COVID-19 on mechanical ventilation - a prospective observational pilot study

BACKGROUND

Coronavirus disease (COVID-19) associated endotheliopathy and microvascular dysfunction are of concern.

OBJECTIVE

The objective of the present single-center observational pilot study was to compare endothelial glycocalyx (EG) damage and endotheliopathy in patients with severe COVID-19 (COVID-19 group) with patients with bacterial pneumonia with septic shock (non-COVID group).

METHODS

Biomarkers of EG damage (syndecan-1), endothelial cells (EC) damage (thrombomodulin), and activation (P-selectin) were measured in blood on three consecutive days from admission to the intensive care unit (ICU). The sublingual microcirculation was studied by Side-stream Dark Field (SDF) imaging with automatic assessment.

RESULTS

We enrolled 13 patients in the non-COVID group (mean age 70 years, 6 women), and 15 in the COVID-19 group (64 years old, 3 women). The plasma concentrations of syndecan-1 were significantly higher in the COVID-19 group during all three days. Differences regarding other biomarkers were not statistically significant. The assessment of the sublingual microcirculation showed improvement on Day 2 in the COVID-19 group. Plasma levels of C-reactive protein (CRP) were significantly higher on the first two days in the COVID-19 group. Plasma syndecan-1 and CRP were higher in patients suffering from severe COVID-19 pneumonia compared to bacterial pneumonia patients.

CONCLUSIONS

These findings support the role of EG injury in the microvascular dysfunction in COVID-19 patients who require ICU.

Components of the Endogenous Cannabinoid System as Potential Biomarkers for Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic condition causing bladder pressure and pain. The condition is of unknown etiology and is often accompanied by other symptoms, including chronic pelvic pain, increased urinary urgency, and frequency. There is no definitive diagnosis for IC/BPS, and treatment options are currently limited to physical therapy and medications to help alleviate symptoms. The endogenous cannabinoid system (ECS) is an important regulator of numerous physiological systems, including the urinary system. Modulations of the ECS have been shown to be beneficial for IC/BPS-associated pain and inflammation in rodents. As an attempt to identify potential biomarkers for IC/BPS, we reviewed experimental studies where the components of the ECS have been quantified in experimental models of IC/BPS. Further investigations using well-defined animal models and patients’ data are required to obtain stronger evidence regarding the potential for ECS components to be definitive biomarkers for IC/BPS.

Cannabinoid Receptor 1 and 2 Signaling Pathways Involved in Sepsis

ABSTRACT

Sepsis is defined as a life-threatening organ dysfunction, caused by a dysregulated host response to an infection and can progress to septic shock, which represents a major challenge in critical care with a high mortality rate. Currently, there is no definitive treatment available for the dysregulated immune response in sepsis. Therefore, a better understanding of the pathophysiological mechanisms may be useful for elucidating the molecular basis of sepsis and may contribute to the development of new therapeutic strategies. The endocannabinoid system is an emerging research topic for the modulation of the host immune response under various pathological conditions. Cannabinoid receptors include the cannabinoid type 1 receptor (CB1) and the cannabinoid type 2 receptor (CB2). This review addresses the main functionality of CB1 and CB2 in sepsis, which can contribute to a better understanding about the pathophysiology of sepsis. Specifically, we discuss the role of CB1 in the cardiovascular system which is one of the biological systems that are strongly affected by sepsis and septic shock. We are also reviewing the role of CB2 in sepsis, specially CB2 activation, which exerts anti-inflammatory activities with potential benefit in sepsis.

Clinical features of pneumonia in severely malnourished children with diarrhoea compared to those without diarrhoea

Introduction: Pneumonia and diarrhoea are amongst the most common causes for hospital admission for children in low- and middle-income countries such as Bangladesh. Undernourished children often have more severe infections and a higher morbidity and mortality. Objective: The objective of this study was to determine the clinical features and outcomes of pneumonia in severely malnourished children with and without diarrhoea. Methodology: A retrospective chart analysis was carried out on children under 5 years of age who were admitted in intensive care unit of the Dhaka hospital of International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). A total of 245 severe acute malnourished children with pneumonia and diarrhoea (PD group) were compared with 89 children with pneumonia only (PO group). Results: A significantly higher number of children from the PD group had some/severe dehydration (16.3% vs. 1.1%; p < 0.005) when compared with children from the PO group. The PD group showed less cough (83.3% vs. 100%; p < 0.001), lower chest wall indrawing (40.4% vs. 60.7%; p = 0.001), and crackles (62.4% vs. 87.6%; p < 0.001) compared to the PO group at the time of admission. Conclusion: Early diagnosis and treatment of some/severe dehydration in addition to WHO recommended other routine treatment of diarrhoea, pneumonia and severe acute malnutrition in children may help to reduce childhood morbidity and mortality especially in low- and middle-income countries.

Utility of intestinal intravital microscopy for the study of CNS injury-induced immunodepression syndrome (CIDS)

BACKGROUND

Stroke, traumatic brain injury, or other forms of central nervous system (CNS) injury initiate a local inflammatory response. Compensatory anti-inflammatory pathways are activated to limit secondary damage due to inflammation. The associated release of immunosuppressing neuromodulators can result in system-wide immune dysregulation (CNS injury-induced immune-depression syndrome -CIDS).

OBJECTIVE

To establish an experimental stroke model where CIDS can be studied by intravital microscopy (IVM).

METHODS

We used the photothrombotic stroke (PTS) model in C57BL/6 mice and studied its effects on peripheral immunity following challenge with lipopolysaccharide (LPS). Leukocyte activation, as well as capillary perfusion of the microcirculation, were assessed using intestinal intravital microscopy (IVM).

RESULTS

PTS caused a significant reduction in the number of adhering leukocytes in submucosal venules of the terminal ileum of mice challenged with LPS compared to LPS-challenged animals without stroke. Leukocyte rolling was also impacted by PTS in the submucosal venules. Following stroke, we also observed decreased mucosal functional capillary density (FCD).

CONCLUSIONS

Our results suggest that PTS with subsequent LPS challenge poses as a viable model to further study CIDS using intravital microscopy of the intestinal microcirculation.

Rodent models of ketamine-induced cystitis

AIMS

Long-term or recreational use of ketamine affects the urinary system and can result in ketamine-induced cystitis (KIC). Rodent models of KIC are important to study KIC pathophysiology and are paramount to the future development of therapies for this painful condition. This review aims to provide a summary of rodent models of KIC, focusing on disease induction, experimental methods, and pathological features of the model.

METHOD

A literature search was performed using the National Center for Biotechnology Information (NCBI) Pubmed database up to March 2021. 20 articles met the inclusion criteria and were finally selected.

RESULTS

There are considerable variations in the rodent models used for studying KIC in terms of the strain of the animal being used; dose, duration, and route of ketamine administration to induce KIC, and assessment of pathological features.

CONCLUSION

KIC remains difficult to fully recapitulate in humans. Improved characterization of KIC models and the experimental parameters and meticulous discussion on translational limitations are required to improve the translational value of research using rodent models of KIC.

A porcine model of endothelial glycocalyx damage by enzymatic digestion: A pilot study

BACKGROUND

The endothelial glycocalyx (EG) plays a vital role in the physiology and pathophysiology of human microcirculation. Having relevant EG damage model would be important tool for testing new interventions aiming at EG protection and recovery. We describe the first in vivo EG damage model in pig.

OBJECTIVE

To investigate the course of animal EG damage induced by specific enzymes.

MATERIAL AND METHODS

Four anesthetized piglets received enzymes: 1g hyaluronidase and 25 IU heparanase I intravenously. Blood and urine samples were collected at baseline and 20/40/60/80/100/120 min for detecting markers of endothelial and EG function. Sublingual microcirculation and EG thickness were assessed by Side-stream Dark Field (SDF) imaging and Perfused Boundary Region (PBR) respectively. EG of the mesentery artery was visualized in fluorescent microscopy.

RESULTS

Biochemical marker of EG damage syndecan-1 showed temporary increase with return to baseline and was reflected by PBR values. Albumin levels suggested brief period of capillary leakage (decrease in the serum, increase in the urine) with a trend to normalization. Urine glycosaminoglycans peaked at 120 minutes. Microcirculatory perfusion parameter showed significant alteration. Diffusion parameters were altered with no statistical significance.

CONCLUSION

EG damage induced by specific enzymes was reflected by temporary changes of biochemical makers together with alteration of microcirculation and changes in fluorescent microscopy of EG layer. Our results support to further validate presented model of EG damage on a larger number of animals.

Outbreak of Pseudomonas aeruginosa infections after CT-guided spinal injections

BACKGROUND

Meningitis and spinal infections with Gram-negative bacteria after local injections for treatment of chronic back pain are rare. This study investigated an outbreak of Pseudomonas aeruginosa infections following computed tomography (CT)-guided spinal injections (SI).

METHODS

A case was defined as a spinal infection or meningitis with P. aeruginosa after SI between 10^th January and 1^st March 2019 in the same outpatient clinic. Patients without microbiological evidence of P. aeruginosa but with a favourable response to antimicrobial therapy active against P. aeruginosa were defined as probable cases.

FINDINGS

Twenty-eight of 297 patients receiving CT-guided SI during the study period developed meningitis or spinal infections. Medical records were available for 19 patients. In 15 patients, there was microbiological evidence of P. aeruginosa, and four patients were defined as probable cases. Two of 19 patients developed meningitis, while the remaining 17 patients developed spinal infections. The median time from SI to hospital admission was 8 days (interquartile range 2-23 days). Patients mainly presented with back pain (N=18; 95%), and rarely developed fever (N=3; 16%). Most patients required surgery (N=16; 84%). Seven patients (37%) relapsed and one patient died. Although the source of infection was not identified microbiologically, documented failures in asepsis when performing SI probably contributed to these infections.

CONCLUSIONS

SI is generally considered safe, but non-adherence to asepsis can lead to deleterious effects. Spinal infections caused by P. aeruginosa are difficult to treat and have a high relapse rate.

Real-Time Imaging of Immune Modulation by Cannabinoids Using Intravital Fluorescence Microscopy

Introduction: The endocannabinoid system (ECS) is an endogenous regulatory system involved in a wide range of physiologic and disease processes. Study of ECS regulation provides novel drug targets for disease treatment. Intravital microscopy (IVM), a microscopy-based imaging method that allows the observation of cells and cell-cell interactions within various tissues and organs in vivo, has been utilized to study tissues and cells in their physiologic microenvironment. This article reviews the current state of the IVM techniques used in ECS-related inflammation research. Methodological Aspects of IVM: IVM with focus on conventional fluorescent microscope has been introduced in investigation of microcirculatory function and the behavior of individual circulating cells in an in vivo environment. Experimental setting, tissue protection under physiologic condition, and microscopical observation are described. Application of IVM in Experimental Inflammatory Disorders: Using IVM to investigate the effects of immune modulation by cannabinoids is extensively reviewed. The inflammatory disorders include sepsis, arthritis, diabetes, interstitial cystitis, and inflammatory conditions in the central nervous system and eyes. Conclusion: IVM is a critical tool in cannabinoid and immunology research. It has been applied to investigate the role of the ECS in physiologic and disease processes. This review demonstrates that the IVM technique provides a unique means in understanding ECS regulation on immune responses in diseases under their physical conditions, which could not be achieved by other methods.

Sensitivity Patterns of Bacterial Pathogens Isolated from Blood Cultures of Under-Five Children with Pneumonia and Clinical Sepsis

Treatment options for pneumonia and sepsis by antibiotics are limited due to the development of multidrug-resistant bacterial strains. This unmatched case-control study determined the antibiotic sensitivity against bacterial isolates obtained from septic and nonseptic children with pneumonia. Children of either sex aged 0–59 months with a history of cough or shortness of breath and radiologically confirmed pneumonia were enrolled in this study. Cases with clinical signs of sepsis at admission (n = 151) were compared to cases without sepsis as controls (n = 107). A total of 205 children had a performance of blood culture, with 123 children suffering from clinical sepsis. Blood cultures showed bacterial growth in 19% of the septic samples, with 8% coagulase-negative staphylococci and 2.4% Acinetobacter species. Only 1.6% of the cases were infected by Streptococcus pneumonia, Haemophilus influenzae, Salmonella typhi and Klebsiella. In contrast, children without sepsis presented positive blood cultures with growth of Salmonella typhi in 2.4% of the cases and growth of Klebsiella in 1.2%. Bacteria were sensitive to imipenem in 100% of the cases (86% for meropenem, 83% for ceftazidime and 76% for ciprofloxacin). The mortality rate was significantly higher in children with pneumonia complicated by sepsis (odds ratio (OR) = 3.02, 95% confidence interval (CI), 1.11–8.64, p < 0.027). Knowledge about specific laboratory characteristics in children with pneumonia will facilitate an early diagnosis and treatment of sepsis and reduce mortality.

National Preclinical Sepsis Platform: developing a framework for accelerating innovation in Canadian sepsis research

Despite decades of preclinical research, no experimentally derived therapies for sepsis have been successfully adopted into routine clinical practice. Factors that contribute to this crisis of translation include poor representation by preclinical models of the complex human condition of sepsis, bias in preclinical studies, as well as limitations of single-laboratory methodology. To overcome some of these shortcomings, multicentre preclinical studies—defined as a research experiment conducted in two or more research laboratories with a common protocol and analysis—are expected to maximize transparency, improve reproducibility, and enhance generalizability. The ultimate objective is to increase the efficiency and efficacy of bench-to-bedside translation for preclinical sepsis research and improve outcomes for patients with life-threatening infection. To this end, we organized the first meeting of the National Preclinical Sepsis Platform (NPSP). This multicentre preclinical  research collaboration of Canadian sepsis researchers and stakeholders was established to study the pathophysiology of sepsis and accelerate movement of promising therapeutics into early phase clinical trials. Integrated knowledge translation and shared decision-making were emphasized to ensure the goals of the platform align with clinical researchers and patient partners. 29 participants from 10 independent labs attended and discussed four main topics: (1) objectives of the platform; (2) animal models of sepsis; (3) multicentre methodology and (4) outcomes for evaluation. A PIRO model (predisposition, insult, response, organ dysfunction) for experimental design was proposed to strengthen linkages with interdisciplinary researchers and key stakeholders. This platform represents an important resource for maximizing translational impact of preclinical sepsis research.

Effect of Cannabinoid 2 Receptor Modulation on the Peripheral Immune Response in Central Nervous System Injury-Induced Immunodeficiency Syndrome

Introduction: Acute central nervous system (CNS) injury, such as stroke, spinal cord injury, or traumatic brain injury can result in dysregulated immune response, and the condition is known as CNS injury-induced immunodeficiency syndrome (CIDS). The endocannabinoid system is an important homeostatic regulator in the CNS and immune system. Activation of cannabinoid 2 receptors (CB2R) on immune cells has been reported to dampen inflammation, suggesting a potential role of CB2R in the peripheral immune response following CNS injury. In this study, we have investigated the effect of CB2R modulation on the peripheral immune response during CIDS. Materials and Methods: Experimental CNS injury was induced in C57BL/6 mice through intracerebral injection of the vasopressor peptide, endothelin-1. A selective CB2R agonist (HU308) was used as an early treatment before the onset of CIDS and AM630, a selective CB2R antagonist, was administered as a later-phase therapy to combat the systemic immunodeficiency following the CNS injury. The peripheral immune response to endotoxin was studied 24 h after the CNS injury using intravital microscopy to examine leukocyte activation within the intestinal microcirculation in mice. Brain infarct size, and plasma levels of cytokines and soluble adhesion molecules were measured as additional parameters for the assessment of treatment outcomes. Results: Our results showed that early CB2R activation with HU308 reduced brain injury size and restored leukocyte response to endotoxin in the peripheral microcirculation. Late CB2R inhibition with AM630 also improved the peripheral leukocyte response to endotoxin and did not exacerbate the extent of brain injury. Discussion: CB2R activation has the potential to mitigate CNS injury as an early treatment by limiting neuroinflammation and preventing the development of CIDS. At the later stage with already-established CIDS, treatment may require dampening CB2R activation to improve the patient's outcome.

Intravital Imaging of Pulmonary Immune Response in Inflammation and Infection

Intravital microscopy (IVM) is a unique imaging method providing insights in cellular functions and interactions in real-time, without the need for tissue extraction from the body. IVM of the lungs has specific challenges such as restricted organ accessibility, respiratory movements, and limited penetration depth. Various surgical approaches and microscopic setups have been adapted in order to overcome these challenges. Among others, these include the development of suction stabilized lung windows and the use of more advanced optical techniques. Consequently, lung IVM has uncovered mechanisms of leukocyte recruitment and function in several models of pulmonary inflammation and infection. This review focuses on bacterial pneumonia, aspiration pneumonia, sepsis-induced acute lung Injury, and cystic fibrosis, as examples of lung inflammation and infection. In addition, critical details of intravital imaging techniques of the lungs are discussed.

Comparison of Treatment Effects of Different Iron Chelators in Experimental Models of Sepsis

Growing evidence indicates that dysregulated iron metabolism with altered and excess iron availability in some body compartments plays a significant role in the course of infection and sepsis in humans. Given that all bacterial pathogens require iron for growth, that iron withdrawal is a normal component of innate host defenses and that bacterial pathogens have acquired increasing levels of antibiotic resistance, targeting infection and sepsis through use of appropriate iron chelators has potential to provide new therapeutics. We have directly compared the effects of three Food and Drug Administration (FDA)-approved chelators (deferoxamine—DFO; deferiprone—DFP; and deferasirox—DFX), as were developed for treating hematological iron overload conditions, to DIBI, a novel purpose-designed, anti-infective and anti-inflammatory water-soluble hydroxypyridinone containing iron-selective copolymers. Two murine sepsis models, endotoxemia and polymicrobial abdominal sepsis, were utilized to help differentiate anti-inflammatory versus anti-infective activities of the chelators. Leukocyte adhesion, as measured by intravital microscopy, was observed in both models, with DIBI providing the most effective reduction and DFX the poorest. Inflammation in the abdominal sepsis model, assessed by cytokine measurements, indicated exacerbation by DFX and DFO for plasma Interleukin (IL)-6 and reductions to near-control levels for DIBI and DFP. Peritoneal infection burden was reduced 10-fold by DIBI while DFX and DFP provided no reductions. Overall, the results, together with those from other studies, revealed serious limitations for each of the three hematological chelators, i.e., as potentially repurposed for treating infection/sepsis. In contrast, DIBI provided therapeutic benefits, consistent with various in vitro and in vivo results from other studies, supporting the potential for its use in treating sepsis.

HIV DNA reservoir and elevated PD-1 expression of CD4 T-cell subsets particularly persist in the terminal ileum of HIV-positive patients despite cART

OBJECTIVES

Despite its importance as an HIV anatomic sanctuary, little is known about the characteristics of the HIV reservoir in the terminal ileum (TI). In blood, the immune checkpoint inhibitor programmed-death-1 (PD-1) has been linked to the HIV reservoir and T-cell immune dysfunction. We thus evaluated PD-1 expression and cell-associated HIV DNA in memory CD4 T-cell subsets from TI, peripheral blood (PB) and rectum (RE) of untreated and treated HIV-positive patients to identify associations between PD-1 and HIV reservoir in other sites.

METHODS

Using mononuclear cells from PB, TI and RE of untreated HIV-positive (N = 6), treated (n = 18) HIV-positive and uninfected individuals (n = 16), we identified and sorted distinct memory CD4 T-cell subsets by flow cytometry, quantified their cell-associated HIV DNA using quantitative PCR and assessed PD-1 expression levels using geometric mean fluorescence intensity. Combined HIV-1 RNA in situ hybridization and immunohistochemistry was performed on ileal biopsy sections.

RESULTS

Combined antiretroviral therapy (cART)-treated patients with undetectable HIV RNA and significantly lower levels of HIV DNA in PB showed particularly high PD-1 expression in PB and TI, and high HIV DNA levels in TI, irrespective of clinical characteristics. By contrast, in treatment-naïve patients HIV DNA levels in memory CD4 T-cell subsets were high in PB and TI.

CONCLUSION

Elevated PD-1 expression on memory CD4 T-cells in PB and TI despite treatment points to continuous immune dysfunction and underlines the importance of evaluating immunotherapy in reversing HIV latency and T-cell reconstitution. As HIV DNA particularly persists in TI despite cART, investigating samples from TI is crucial in understanding HIV immunopathogenesis.