Rapid diagnostics for point-of-care quantification of soluble transferrin receptor

Detecting labile heme and ferroptosis through 'turn-on' fluorescence and lipid droplet localization post Fe2+ sensing

Iron, a crucial biologically active ion essential for metabolic processes in living organisms, plays a vital role in biological functions, and imbalances in iron levels can lead to various diseases. In this study, we have developed two simple "turn-on" fluorescent probes, NOPy and NOCN, for the quick and selective detection of Fe2+ at nanomolar levels (LOD of 35 nM), accompanied by significant absorption and emission shifts, along with colorimetric demarcation. Both fluorophores exhibit an excellent "turn-on" emission response upon encountering Fe2+ in the cells. Flow cytometry and confocal fluorescence imaging studies demonstrate enhanced fluorescence signals in response to labile iron, efficiently detecting heme during erastin-induced ferroptosis. Interestingly, we also observed that the product formed after Fe2+ sensing localizes within the lipid droplets. These water-soluble and highly sensitive reactive probes, NOPy and NOCN, enable investigations of iron-dependent physiological and pathological conditions. The development of these probes represents an advancement in the field, offering a rapid and selective means for detecting Fe2+ with minimal cytotoxicity.

Unraveling the Role of Maternal Serum Ferritin Levels in Preterm Delivery: A Comprehensive Review

Preterm delivery remains a critical global health concern, with numerous adverse consequences for both neonate and healthcare systems. Understanding the relationship between maternal ferritin levels, as a marker of iron status, and the risk of preterm birth is the focal point of this comprehensive review. We provide insights into the multifaceted nature of this connection, highlighting factors that influence maternal ferritin levels, including dietary intake, genetic and physiological variations, comorbidities, and iron supplementation. While evidence suggests an association between low maternal ferritin levels and preterm birth, causality remains elusive, necessitating further research with robust study designs. The potential mechanisms linking maternal iron status to preterm birth, such as inflammation, infection, and oxidative stress, are explored, underscoring the need for in-depth investigations. This comprehensive review emphasizes the clinical importance of assessing and monitoring maternal ferritin levels in prenatal care and advocates for public health initiatives to raise awareness and provide targeted interventions, particularly in high-risk populations. As we strive to address these unanswered questions and embark on innovative research directions, the aim is to ultimately enhance our understanding of the complex relationship between maternal iron status and preterm birth, leading to improved maternal and child health outcomes.

Precision Nutrition Opportunities to Help Mitigate Nutrition and Health Challenges in Low- and Middle-Income Countries: An Expert Opinion Survey

Precision nutrition involves several data collection methods and tools that aim to better inform nutritional recommendations and improve dietary intake, nutritional status, and health outcomes. While the benefits of collecting precise data and designing well-informed interventions are vast, it is presently unclear whether precision nutrition is a relevant approach for tackling nutrition challenges facing populations in low- and middle-income countries (LMIC), considering infrastructure, affordability, and accessibility of approaches. The Swiss Food & Nutrition Valley (SFNV) Precision Nutrition for LMIC project working group assessed the relevance of precision nutrition for LMIC by first conducting an expert opinion survey and then hosting a workshop with nutrition leaders who live or work in LMIC. The experts were interviewed to discuss four topics: nutritional problems, current solutions, precision nutrition, and collaboration. Furthermore, the SFNV Precision Nutrition for LMIC Virtual Workshop gathered a wider group of nutrition leaders to further discuss precision nutrition relevance and opportunities. Our study revealed that precision public health nutrition, which has a clear focus on the stratification of at-risk groups, may offer relevant support for nutrition and health issues in LMIC. However, funding, affordability, resources, awareness, training, suitable tools, and safety are essential prerequisites for implementation and to equitably address nutrition challenges in low-resource communities.

Umbilical cord management - the first opportunity to improve healthcare disparities

This review focuses on iron deficiency and iron deficiency anemia in women and children in the United States. These are common, fixable problems that disproportionally affect minority populations. There are many opportunities for successful screening and management. The knowledge and awareness for identification and treatment of our populations' commonest deficiency is crucial.

Low-cost, point-of-care biomarker quantification

Low-cost, point-of-care (POC) devices that allow fast, on-site disease diagnosis could have a major global health impact, particularly if they can provide quantitative measurement of molecules indicative of a diseased state (biomarkers). Accurate quantification of biomarkers in patient samples is already challenging when research-grade, sophisticated equipment is available; it is even more difficult when constrained to simple, cost-effective POC platforms. Here, we summarize the main challenges to accurate, low-cost POC biomarker quantification. We also review recent efforts to develop and implement POC tools beyond qualitative readouts, and we conclude by identifying important future research directions.

A diagnostic platform for rapid, simultaneous quantification of procalcitonin and C-reactive protein in human serum

Background

Early and accurate determination of bacterial infections as a potential cause for a patient's systemic inflammatory response is required for timely administration of appropriate treatment and antibiotic stewardship. Procalcitonin (PCT) and C-reactive protein (CRP) have both been used as biomarkers to infer bacterial infections, particularly in the context of sepsis. There is an urgent need to develop a platform for simultaneous quantification of PCT and CRP, to enable the potential use of these biomarkers at the point-of-care.

Methods

A multiplexed lateral flow assay (LFA) and a fluorescence optical reader were developed. Assay performance was validated by testing spiked antigens in the buffer, followed by a validation study comparing results with conventional assays (Roche Cobas e411 Elecsys PCT and Siemens ADVIA XPT CRP) in 25 archived remnant human serum samples.

Findings

A linear regression correlation of 0·97 (P < 0·01) was observed for PCT, and a correlation of 0·95 (P < 0·01) was observed for CRP using direct patient samples. We also validated our platform's ability to accurately quantify high-dose CRP in the hook effect range where excess unlabeled analytes occupy binding sites at test lines.

Interpretation

A fluorescence reader-based duplex LFA for simultaneous quantification of PCT and CRP was developed and successfully validated with clinical samples. The rapid, portable, and low-cost nature of the platform offers potential for differentiation of bacterial and viral infections in emergency and low-resource settings at the point-of-care.

Funding

NIH/NIBIB Award 1R01EB021331, and Academic Venture Fund from the Atkinson Center for a Sustainable Future at Cornell University.

Two-Color Duplex Platform for Point-of-Care Differential Detection of Malaria and Typhoid Fever

Malaria and typhoid fever are two febrile illnesses prevalent in the tropics that often present overlapping symptoms. In this work, we demonstrate an optical reader-based diagnostics platform for rapid codetection and quantification of two antigen targets: lipopolysaccharide (LPS) for typhoid fever and plasmodium lactate dehydrogenase (pLDH) for malaria infections. We report a limit of detection (LoD) of 5 ng/mL for LPS and 10 ng/mL for pLDH in a spiked serum test. We also validated the duplex test's performance of differentiating malaria infection, typhoid fever infection, and coinfection by testing clinical samples in human serum. Our platform provides the potential for further multiplexing by encoding different color codes to various detection targets. The rapid result (∼15 min), low cost (∼$2), and minimal volume requirement for human serum clinical samples (4 μL) of our diagnostic platform offer great potential for deployment in resource-limited settings to help distinguish common causes for acute febrile illnesses at the point-of-need.

Nano-sensing and nano-therapy targeting central players in iron homeostasis

Iron plays vital roles in many life activities and it is strictly controlled via elaborate metabolic system. Growing evidence has suggested that the dysfunctional iron homeostasis is implicated to many refractory diseases including cancers and neurodegenerations. Systemic and cellular iron are regulated through different pathways but are meanwhile interconnecting with each other via a few key regulators, whose abnormal expressions are often found to be the root causes of many iron disorders. Nano-sensing techniques have enabled the detection and monitoring of such central players, which provide rich information for the iron homeostasis profile through multiplexing and flexible designs. In addition to general sensing, nanoprobes are capable of target imaging and precise local access, which are particularly beneficial for revealing the conditions of intra-/extracellular environments. Nanomaterials have also been applied in some therapies, targeting the aberrant iron metabolism. Various iron uptake pathways have been utilized for target drug delivery and iron level manipulation, while abnormal iron content is notably useful in tumor killing. With brief introduction to the significance of iron homeostasis, this review includes recent works regarding the nanotechnology that has been applied in iron-related diagnostic and therapeutic applications. This article is categorized under: Diagnostic Tools > Biosensing Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

A point-of-care assay for alpha-1-acid glycoprotein as a diagnostic tool for rapid, mobile-based determination of inflammation

BACKGROUND

Inflammation is a key component of immune response to infections and pathogenesis of metabolic and cardiovascular diseases. Inflammatory biomarkers, including alpha-1-acid glycoprotein (AGP), are considered prognostic tools for predicting risk, monitoring response to therapy, and adjusting nutritional biomarkers for accurate interpretation. Serum is considered a primary source of biomarkers; urine and saliva are increasingly being explored and utilized as rapidly accessible, noninvasive biofluids requiring minimal sample processing and posing fewer biohazard risks.

METHODS

A lateral flow immunoassay was developed for an established mobile-based platform to quantify AGP in human serum, urine, and saliva. Assay performance was assessed with purified AGP in buffer, diluted human serum samples (n = 16) banked from a trial in people living with HIV, and saliva and urine (n = 15 each) from healthy participants. Reference methods were conventional clinical chemistry analyzer or commercial ELISA. Bootstrap analysis was used to train and validate sample calibration.

FINDINGS

The correlation between the assay and reference method for serum was 0.97 (P < 0.001). Mean (95% CI) best fit line slope was 1.0 (0.88, 1.15) and intercept was -0.003 (-0.08, 0.09). The correlation for urine was 0.93, and for saliva was 0.97 (both P < 0.001). The median CV for the LFIA for AGP in buffer was 13.2% and for all samples was 28.7%.

INTERPRETATION

The performance of the assay indicated potential use as a rapid, low sample volume input, and easy method to quantify AGP that can be licensed and adopted by commercial manufacturers for regulatory approvals and production. This has future applications for determining inflammatory status either alone or in conjunction with other inflammatory proteins such as C-reactive protein for prognostic, monitoring, or nutritional status applications, including large-scale country level surveys conducted by the DHS and those recommended by the WHO.

The Importance of Iron Status for Young Children in Low- and Middle-Income Countries: A Narrative Review

Early childhood is characterised by high physiological iron demand to support processes including blood volume expansion, brain development and tissue growth. Iron is also required for other essential functions including the generation of effective immune responses. Adequate iron status is therefore a prerequisite for optimal child development, yet nutritional iron deficiency and inflammation-related iron restriction are widespread amongst young children in low- and middle-income countries (LMICs), meaning iron demands are frequently not met. Consequently, therapeutic iron interventions are commonly recommended. However, iron also influences infection pathogenesis: iron deficiency reduces the risk of malaria, while therapeutic iron may increase susceptibility to malaria, respiratory and gastrointestinal infections, besides reshaping the intestinal microbiome. This means caution should be employed in administering iron interventions to young children in LMIC settings with high infection burdens. In this narrative review, we first examine demand and supply of iron during early childhood, in relation to the molecular understanding of systemic iron control. We then evaluate the importance of iron for distinct aspects of physiology and development, particularly focusing on young LMIC children. We finally discuss the implications and potential for interventions aimed at improving iron status whilst minimising infection-related risks in such settings. Optimal iron intervention strategies will likely need to be individually or setting-specifically adapted according to iron deficiency, inflammation status and infection risk, while maximising iron bioavailability and considering the trade-offs between benefits and risks for different aspects of physiology. The effectiveness of alternative approaches not centred around nutritional iron interventions for children should also be thoroughly evaluated: these include direct targeting of common causes of infection/inflammation, and maternal iron administration during pregnancy.