Advances in Clinical Mass Spectrometry

Accurate Clinical Detection of Vitamin D by Mass Spectrometry: A Review

Vitamin D deficiency is thought to be associated with a wide range of diseases, including diabetes, cancer, depression, neurodegenerative diseases, and cardiovascular and cerebrovascular diseases. This vitamin D deficiency is a global epidemic affecting both developing and developed countries and therefore qualitative and quantitative analysis of vitamin D in a clinical context is essential. Mass spectrometry has played an increasingly important role in the clinical analysis of vitamin D because of its accuracy, sensitivity, specificity, and the ability to detect multiple substances at the same time. Despite their many advantages, mass spectrometry-based methods are not without analytical challenges. Front-end and back-end challenges such as protein precipitation, analyte extraction, derivatization, mass spectrometer functionality, must be carefully considered to provide accurate and robust analysis of vitamin D through a well-designed approach with continuous control by internal and external quality control. Therefore, the aim of this review is to provide a comprehensive overview of the development of mass spectrometry methods for vitamin D accurate analysis, including emphasis on status markers, deleterious effects of biological matrices, derivatization reactions, effects of ionization sources, contribution of epimers, standardization of assays between laboratories.

Clinical Proteomics for Solid Organ Tissues

The evaluation of biopsied solid organ tissue has long relied on visual examination using a microscope. Immunohistochemistry is critical in this process, labeling and detecting cell lineage markers and therapeutic targets. However, while the practice of immunohistochemistry has reshaped diagnostic pathology and facilitated improvements in cancer treatment, it has also been subject to pervasive challenges with respect to standardization and reproducibility. Efforts are ongoing to improve immunohistochemistry, but for some applications, the benefit of such initiatives could be impeded by its reliance on monospecific antibody-protein reagents and limited multiplexing capacity. This perspective surveys the relevant challenges facing traditional immunohistochemistry and describes how mass spectrometry, particularly liquid chromatography-tandem mass spectrometry, could help alleviate problems. In particular, targeted mass spectrometry assays could facilitate measurements of individual proteins or analyte panels, using internal standards for more robust quantification and improved interlaboratory reproducibility. Meanwhile, untargeted mass spectrometry, showcased to date clinically in the form of amyloid typing, is inherently multiplexed, facilitating the detection and crude quantification of 100s to 1000s of proteins in a single analysis. Further, data-independent acquisition has yet to be applied in clinical practice, but offers particular strengths that could appeal to clinical users. Finally, we discuss the guidance that is needed to facilitate broader utilization in clinical environments and achieve standardization.

Variations of nonvolatile taste components of mushrooms with different operating conditions and parameters from farm to fork

Mushroom is a sustainable food option and a meat substitute which yet needs some strategies to enhance sensory attributes. Especially, their taste characteristics (nonvolatile taste components: soluble sugars, organic acids, free amino acids, and 5'-nucleotides) can vary significantly due to operating conditions and parameters during different stages from farm to fork. This review is aimed to provide an overall view of the determined effects of operating conditions and parameters for mushroom taste attributes, suggestions for future research from lacking variables, and some recommendations for improving the taste perception of mushrooms. Taste compounds of mushrooms alter differently based on cultivation (species, cultivation or maturity stage, substrate composition, part, grade, mycelium strain), cooking (cooking method, time, temperature), preservation, and post-harvest storage conditions (drying parameters, pretreatment, preservation method, gamma irradiation, packaging, storage time and temperature). The dominant tastes of mushrooms given by sweet and umami taste active substances can be enhanced significantly with proper control of parameters during cultivation, cooking, drying, or post-harvest storage. The parameters and variations organized in this review can be used to develop a mathematical model for obtaining optimum taste attributes of mushrooms and mushroom-based meat alternatives and to discover the variables of mushroom species not studied yet.

Changes in Content of Bioactive Compounds and Antioxidant Activity Induced in Needles of Different Half-Sib Families of Norway Spruce (Picea abies (L.) H. Karst) by Seed Treatment with Cold Plasma

In order to ensure sufficient food resources for a constantly growing human population, new technologies (e.g., cold plasma technologies) are being developed for increasing the germination and seedling growth without negative effects on the environment. Pinaceae species are considered a natural source of antioxidant compounds and are valued for their pharmaceutical and nutraceutical properties. In this study, the seeds of seven different Norway spruce half-sib families were processed for one or two minutes with cold plasma (CP) using dielectric barrier discharge (DBD) plasma equipment. At the end of the second vegetation season, the total flavonoid content (TFC), DPPH (2,2- diphenyl-1-picryl-hydrazyl-hydrate), and ABTS (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) antioxidant activity, and the amounts of six organic acids (folic, malic, citric, oxalic, succinic, and ascorbic) were determined in the needles of different half-sib families of Norway spruce seedlings. The results show that the TFC, antioxidant activity, and amounts of organic acids in the seedling needles depended on both the treatment duration and the genetic family. The strongest positive effect on the TFC was determined in the seedlings of the 477, 599, and 541 half-sib families after seed treatment with CP for 1 min (CP1). The TFC in these families increased from 118.06 mg g⁻¹ to 312.6 mg g⁻¹ compared to the control. Moreover, seed treatment with CP1 resulted in the strongest increase in the antioxidant activity of the needles of the 541 half-sib family seedlings; the antioxidant activity, determined by DPPH and ABTS tests, increased by 30 and 23%, respectively, compared to the control. The obtained results indicate that the CP effect on the amount of organic acids in the needles was dependent on the half-sib family. It was determined that treatment with CP1 increased the amount of five organic acids in the needles of the 541 half-sib family seedlings. The presented results show future possibilities for using cold plasma seed treatment in the food and pharmacy industries.

Potential Feed Additives as Antibiotic Alternatives in Broiler Production

This article aimed to describe the current use scenario, alternative feed additives, modes of action and ameliorative effects in broiler production. Alternative feed additives have promising importance in broiler production due to the ban on the use of certain antibiotics. The most used antibiotic alternatives in broiler production are phytogenics, organic acids, prebiotics, probiotics, enzymes, and their derivatives. Antibiotic alternatives have been reported to increase feed intake, stimulate digestion, improve feed efficiency, increase growth performance, and reduce the incidence of diseases by modulating the intestinal microbiota and immune system, inhibiting pathogens, and improving intestinal integrity. Simply, the gut microbiota is the target to raise the health benefits and growth-promoting effects of feed additives on broilers. Therefore, naturally available feed additives are promising antibiotic alternatives for broilers. Then, summarizing the category, mode of action, and ameliorative effects of potential antibiotic alternatives on broiler production may provide more informed decisions for broiler nutritionists, researchers, feed manufacturers, and producers.

Butyric and Citric Acids and Their Salts in Poultry Nutrition: Effects on Gut Health and Intestinal Microbiota

Intestinal dysfunction of farm animals, such as intestinal inflammation and altered gut microbiota, is the critical problem affecting animal welfare, performance and farm profitability. China has prohibited the use of antibiotics to improve feed efficiency and growth performance for farm animals, including poultry, in 2020. With the advantages of maintaining gut homeostasis, enhancing digestion, and absorption and modulating gut microbiota, organic acids are regarded as promising antibiotic alternatives. Butyric and citric acids as presentative organic acids positively impact growth performance, welfare, and intestinal health of livestock mainly by reducing pathogenic bacteria and maintaining the gastrointestinal tract (GIT) pH. This review summarizes the discovery of butyric acid (BA), citric acid (CA) and their salt forms, molecular structure and properties, metabolism, biological functions and their applications in poultry nutrition. The research findings about BA, CA and their salts on rats, pigs and humans are also briefly reviewed. Therefore, this review will fill the knowledge gaps of the scientific community and may be of great interest for poultry nutritionists, researchers and feed manufacturers about these two weak organic acids and their effects on intestinal health and gut microbiota community, with the hope of providing safe, healthy and nutrient-rich poultry products to consumers.

A microfluidic platform integrating paper adsorption-based sample clean-up and voltage-assisted liquid desorption electrospray ionization mass spectrometry for biological sample analysis

Clinical application of direct sampling electrospray ionization mass spectrometry (ESI-MS) remains limited due to problems associated with very "dirty" sample matrices. Herein we report on a microfluidic platform that allows direct mass spectrometric analysis of serum samples of microliter sizes. The platform integrates in-line paper adsorption-based sample clean-up and voltage assisted liquid desorption ESI-MS/MS (VAL DESI-MS/MS) to detect multiple targeted compounds of clinical interest. Adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) were selected as model analytes. Simultaneous quantification of these compounds in human serum samples was demonstrated. For all the three compounds, linear calibration curves were obtained in a concentration range from 0.20 to 20.0 μmol/L with r² values ≥ 0.996. Limits of detection were 0.019, 0.015, and 0.011 μmol/L for AMP, ADP, and ATP, respectively. Recovery was found in the range from 96.5% to 103.5% at spiking concentrations of 0.25 and 2.50 μmol/L. The results indicate that the proposed microfluidic mass spectrometric platform is robust and effective. It may have a potential in clinical analysis.

Differential Mobility Spectrometry-Mass Spectrometry (DMS-MS) in Radiation Biodosimetry: Rapid and High-Throughput Quantitation of Multiple Radiation Biomarkers in Nonhuman Primate Urine

High-throughput methods to assess radiation exposure are a priority due to concerns that include nuclear power accidents, the spread of nuclear weapon capability, and the risk of terrorist attacks. Metabolomics, the assessment of small molecules in an easily accessible sample, is the most recent method to be applied for the identification of biomarkers of the biological radiation response with a useful dose-response profile. Profiling for biomarker identification is frequently done using an LC-MS platform which has limited throughput due to the time-consuming nature of chromatography. We present here a chromatography-free simplified method for quantitative analysis of seven metabolites in urine with radiation dose-response using urine samples provided from the Pannkuk et al. (2015) study of long-term (7-day) radiation response in nonhuman primates (NHP). The stable isotope dilution (SID) analytical method consists of sample preparation by strong cation exchange-solid phase extraction (SCX-SPE) to remove interferences and concentrate the metabolites of interest, followed by differential mobility spectrometry (DMS) ion filtration to select the ion of interest and reduce chemical background, followed by mass spectrometry (overall SID-SPE-DMS-MS). Since no chromatography is used, calibration curves were prepared rapidly, in under 2 h (including SPE) for six simultaneously analyzed radiation biomarkers. The seventh, creatinine, was measured separately after 2500× dilution. Creatinine plays a dual role, measuring kidney glomerular filtration rate (GFR), and indicating kidney damage at high doses. The current quantitative method using SID-SPE-DMS-MS provides throughput which is 7.5 to 30 times higher than that of LC-MS and provides a path to pre-clinical radiation dose estimation. Graphical Abstract.

Sensitive quantification of the somatostatin analog AP102 in plasma by ultra-high pressure liquid chromatography-tandem mass spectrometry and application to a pharmacokinetic study in rats

AP102 is a di-iodinated octapeptide somatostatin agonist (SSA) designed to treat acromegaly and neuroendocrine tumors. A sensitive and selective method was validated for the quantification of AP102 in plasma following the European Medicines Agency (EMA) and Food and Drug Administration (FDA) guidelines. Sample preparation was performed using solid-phase extraction microplates. Chromatographic separation was achieved on an ultra-high pressure liquid chromatography (UHPLC) C18 column in 6.0 minutes. The compounds were quantified using multiple reaction monitoring on a tandem quadrupole mass spectrometer with ¹³ C,¹⁵ N-labeled AP102 as internal standard. Calibration ranged from 50 to 10000 pg/mL. The lower limit of quantification (LLOQ) was measured at 20 pg/mL, and robust analytical performances were obtained with trueness at 99.2%-100.0%, intra-assay imprecision at 2.5%-4.4%, and inter-assay imprecision at 8.9%-9.7%. The accuracy profiles (total error) built on the 3 concentrations levels showed accuracy within the 70%-130% range. AP102 is remarkably stable since no proteolytic fragments were detected on plasma samples analyzed by Orbitrap-MS. Pharmacokinetic studies were conducted in rats, after single dose (1, 3, and 10 μg/kg, sc) and continuous subcutaneous administration (osmotic minipumps for 28 days, 3.0 or 10.0 μg/kg/h). AP102 showed a rapid absorption by the subcutaneous route (T_max : 15-30 minutes) and a fast elimination (t_1/2 : 33-86 minutes). The PK profile of AP102 exhibited a mean clearance of 1.67 L/h and a mean distribution volume at steady state of 7.16 L/kg, about 10-fold higher than those observed with other SSA or non- and mono-iodinated AP102. LogD_7.4 determination confirmed the lipophilic properties of AP102 that might influence its distribution in tissues.