Interaction of the chemotherapeutic agent oxaliplatin and the tyrosine kinase inhibitor dasatinib with the organic cation transporter 2.

Oxaliplatin (OHP) is effective in colorectal cancer treatment but induces peripheral neurotoxicity (OHP-induced peripheral neurotoxicity, OIPN), diminishing survivor quality of life. Organic cation transporter 2 (OCT2) is a key OHP uptake pathway in dorsal root ganglia. Competing for OCT2-mediated OHP uptake, such as with the tyrosine kinase inhibitor dasatinib, may mitigate OHP side effects. We investigated OHP and dasatinib interaction with OCT2 in human embryonic kidney 293 (HEK293) cells expressing OCT2 within a 10-3 to 10-7 M concentration range. Uptake competition experiments using fluorescent organic cation 4-(4-dimethylaminostyryl)-N-methylpyridinium (ASP+, 1 µM) and mass spectrometry (MS) to determine cellular platinum content indicated that OHP (100 µM) is an OCT2 substrate, mediating OHP cellular toxicity. ASP+ and MS analysis revealed dasatinib as a non-transported inhibitor of hOCT2 (IC50 = 5.9 µM) and as a regulator of OCT2 activity. Dasatinib reduced transporter Vmax, potentially via Y544 phosphorylation suppression. MS analysis showed cellular dasatinib accumulation independent of hOCT2. Although 3 µM dasatinib reduced 100 µM OHP accumulation in hOCT2-HEK293 cells, co-incubation with dasatinib and OHP did not prevent OHP toxicity, possibly due to dasatinib-induced cell viability reduction. In summary, this study demonstrates OHP as an OCT2 substrate and dasatinib as a non-transported inhibitor and regulator of OCT2, offering potential for OIPN mitigation.

High-throughput Raman spectroscopy allows ex vivo characterization of murine small intestinal intra-epithelial lymphocytes (IEL).

T cells are considered to be critical drivers of intestinal inflammation in mice and people. The so called intra-epithelial lymphocyte (IEL) compartment largely consist of T cells. Interestingly, the specific regulation and contribution of IELs in the context of inflammatory bowel disease remains poorly understood, in part due to the lack of appropriate analysis tools. Powerful, label-free methods could ultimately provide access to this cell population and hence give valuable insight into IEL biology and even more to their disease-related functionalities. Raman spectroscopy has demonstrated over the last few years its potential for reliable cell characterization and differentiation, but its utility in regard to IEL exploration remains unknown. To address this question experimentally, we utilized a murine, T cell-driven experimental model system which is accepted to model human gut inflammation. Here, we repopulated the small intestinal IEL compartment (SI IELs) of Rag1-deficient mice endogenously lacking T cells by transferring naïve CD4+ T helper cells intraperitoneally. Using multivariate statistical analysis, high-throughput Raman spectroscopy managed to define a cell subpopulation ex vivo within the SI IEL pool of mice previously receiving T cells in vivo that displayed characteristic spectral features of lymphocytes. Raman data sets matched flow cytometry analyses with the latter identifying T cell receptor (TCR)αß+ CD4+ T cell population in SI IELs from T cell-transferred mice, but not from control mice, in an abundance comparable to the one detected by Raman spectroscopy. Hence, in this study, we provide experimental evidence for high-throughput Raman spectroscopy to be a novel, future tool to reliably identify and potentially further characterize the T cell pool of small intestinal IELs ex vivo.

Identification of bacteria in mixed infection from urinary tract of patient's samples using Raman analysis of dried droplets.

Urinary tract infections (UTI) are among the most frequent nosocomial infections. A fast identification of the pathogen and assignment of Gram type could help to prescribe most suitable treatments. Raman spectroscopy holds high potential for fast and reliable bacterial pathogens identification. While most studies so far have focused on individual pathogens or artificial mixtures, this contribution aims to translate the analysis to primary urine samples from patients with suspected UTIs. For this, we have included 59 primary urine samples out of which 29 were diagnosed as mixed infections. For Raman analysis, we first trained two classification models based on principal component analysis - linear discriminant analysis (PCA-LDA) with more than 3500 Raman spectra of 85 clinical isolates from 23 species in order to (1) identify the Gram type of the bacteria and (2) assign family membership to one of the six most abundant bacterial families in urinary tract infections (Enterobacteriaceae, Morganellaceae, Pseudomonadaceae, Enterococcaceae, Staphylococcaceae and Streptococcaceae). The classification models were applied to artificial mixtures of Gram positive and Gram negative bacteria to correctly predict mixed infections with an accuracy of 75%. Raman scans of dried droplets did not yet yield optimal classification results on family level. When translating the method to primary urine samples, we observed a strong bias towards Gram negative bacteria, on family level towards Morganellaceae, which reduced prediction accuracy. Spectral differences were observed between isolates grown on standard growth medium and bacteria of the same strain when characterized directly from the patient. Thus, improvement of the classification accuracy is expected with a larger data base containing also bacteria measured directly from the urine sample.

Regulation of Transporters for Organic Cations by High Glucose.

Endogenous positively charged organic substances, including neurotransmitters and cationic uremic toxins, as well as exogenous organic cations such as the anti-diabetic medication metformin, serve as substrates for organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs). These proteins facilitate their transport across cell membranes. Vectorial transport through the OCT/MATE axis mediates the hepatic and renal excretion of organic cations, regulating their systemic and local concentrations. Organic cation transporters are part of the remote sensing and signaling system, whose activity can be regulated to cope with changes in the composition of extra- and intracellular fluids. Glucose, as a source of energy, can also function as a crucial signaling molecule, regulating gene expression in various organs and tissues. Its concentration in the blood may fluctuate in specific physiological and pathophysiological conditions. In this work, the regulation of the activity of organic cation transporters was measured by incubating human embryonic kidney cells stably expressing human OCT1 (hOCT1), hOCT2, or hMATE1 with high glucose concentrations (16.7 mM). Incubation with this high glucose concentration for 48 h significantly stimulated the activity of hOCT1, hOCT2, and hMATE1 by increasing their maximal velocity (Vmax), but without significantly changing their affinity for the substrates. These effects were independent of changes in osmolarity, as the addition of equimolar concentrations of mannitol did not alter transporter activity. The stimulation of transporter activity was associated with a significant increase in transporter mRNA expression. Inhibition of the mechanistic target of rapamycin (mTOR) kinase with Torin-1 suppressed the transporter stimulation induced by incubation with 16.7 mM glucose. Focusing on hOCT2, it was shown that incubation with 16.7 mM glucose increased hOCT2 protein expression in the plasma membrane. Interestingly, an apparent trend towards higher hOCT2 mRNA expression was observed in kidneys from diabetic patients, a pathology characterized by high serum glucose levels. Due to the small number of samples from diabetic patients (three), this observation must be interpreted with caution. In conclusion, incubation for 48 h with a high glucose concentration of 16.7 mM stimulated the activity and expression of organic cation transporters compared to those measured in the presence of 5.6 mM glucose. This stimulation by a diabetic environment could increase cellular uptake of the anti-diabetic drug metformin and increase renal tubular secretion of organic cations in an early stage of diabetes.

Label-Free Characterization of Macrophage Polarization Using Raman Spectroscopy.

Macrophages are important cells of the innate immune system that play many different roles in host defense, a fact that is reflected by their polarization into many distinct subtypes. Depending on their function and phenotype, macrophages can be grossly classified into classically activated macrophages (pro-inflammatory M1 cells), alternatively activated macrophages (anti-inflammatory M2 cells), and non-activated cells (resting M0 cells). A fast, label-free and non-destructive characterization of macrophage phenotypes could be of importance for studying the contribution of the various subtypes to numerous pathologies. In this work, single cell Raman spectroscopic imaging was applied to visualize the characteristic phenotype as well as to discriminate between different human macrophage phenotypes without any label and in a non-destructive manner. Macrophages were derived by differentiation of peripheral blood monocytes of human healthy donors and differently treated to yield M0, M1 and M2 phenotypes, as confirmed by marker analysis using flow cytometry and fluorescence imaging. Raman images of chemically fixed cells of those three macrophage phenotypes were processed using chemometric methods of unmixing (N-FINDR) and discrimination (PCA-LDA). The discrimination models were validated using leave-one donor-out cross-validation. The results show that Raman imaging is able to discriminate between pro- and anti-inflammatory macrophage phenotypes with high accuracy in a non-invasive, non-destructive and label-free manner. The spectral differences observed can be explained by the biochemical characteristics of the different phenotypes.

Raman Spectroscopy Profiling of Splenic T-Cells in Sepsis and Endotoxemia in Mice.

Sepsis is a life-threatening condition that results from an overwhelming and disproportionate host response to an infection. Currently, the quality and extent of the immune response are evaluated based on clinical symptoms and the concentration of inflammatory biomarkers released or expressed by the immune cells. However, the host response toward sepsis is heterogeneous, and the roles of the individual immune cell types have not been fully conceptualized. During sepsis, the spleen plays a vital role in pathogen clearance, such as bacteria by an antibody response, macrophage bactericidal capacity, and bacterial endotoxin detoxification. This study uses Raman spectroscopy to understand the splenic T-lymphocyte compartment profile changes during bona fide bacterial sepsis versus hyperinflammatory endotoxemia. The Raman spectral analysis showed marked changes in splenocytes of mice subjected to septic peritonitis principally in the DNA region, with minor changes in the amino acids and lipoprotein areas, indicating significant transcriptomic activity during sepsis. Furthermore, splenocytes from mice exposed to endotoxic shock by injection of a high dose of lipopolysaccharide showed significant changes in the protein and lipid profiles, albeit with interindividual variations in inflammation severity. In summary, this study provided experimental evidence for the applicability and informative value of Raman spectroscopy for profiling the immune response in a complex, systemic infection scenario. Importantly, changes within the acute phase of inflammation onset (24 h) were reliably detected, lending support to the concept of early treatment and severity control by extracorporeal Raman profiling of immunocyte signatures.

Insights into S. aureus-Induced Bone Deformation in a Mouse Model of Chronic Osteomyelitis Using Fluorescence and Raman Imaging.

Osteomyelitis is an infection of the bone that is often difficult to treat and causes a significant healthcare burden. Staphylococcus aureus is the most common pathogen causing osteomyelitis. Osteomyelitis mouse models have been established to gain further insights into the pathogenesis and host response. Here, we use an established S. aureus hematogenous osteomyelitis mouse model to investigate morphological tissue changes and bacterial localization in chronic osteomyelitis with a focus on the pelvis. X-ray imaging was performed to follow the disease progression. Six weeks post infection, when osteomyelitis had manifested itself with a macroscopically visible bone deformation in the pelvis, we used two orthogonal methods, namely fluorescence imaging and label-free Raman spectroscopy, to characterise tissue changes on a microscopic scale and to localise bacteria in different tissue regions. Hematoxylin and eosin as well as Gram staining were performed as a reference method. We could detect all signs of a chronically florid tissue infection with osseous and soft tissue changes as well as with different inflammatory infiltrate patterns. Large lesions dominated in the investigated tissue samples. Bacteria were found to form abscesses and were distributed in high numbers in the lesion, where they could occasionally also be detected intracellularly. In addition, bacteria were found in lower numbers in surrounding muscle tissue and even in lower numbers in trabecular bone tissue. The Raman spectroscopic imaging revealed a metabolic state of the bacteria with reduced activity in agreement with small cell variants found in other studies. In conclusion, we present novel optical methods to characterise bone infections, including inflammatory host tissue reactions and bacterial adaptation.

Looking Inside Non-Destructively: Label-Free, Raman-Based Visualization of Intracellular Coxiella burnetii.

The life cycle of intracellular pathogens is often complex and can include different morphoforms. Treatment of intracellular infections and unperturbed studying of the pathogen inside the host cell are frequently challenging. Here, we present a Raman-based, label-free, non-invasive, and non-destructive method to localize, visualize, and even quantify intracellular bacteria in 3D within intact host cells in a Coxiella burnetii infection model. C. burnetii is a zoonotic obligate intracellular pathogen that causes infections in ruminant livestock and humans with an acute disease known as Q fever. Using statistical data analysis, no isolation is necessary to gain detailed information on the intracellular pathogen's metabolic state. High-quality false color image stacks with diffraction-limited spatial resolution enable a 3D spatially resolved single host cell analysis that shows excellent agreement with results from transmission electron microscopy. Quantitative analysis at different time points post infection allows to follow the infection cycle with the transition from the large cell variant (LCV) to the small cell variant (SCV) at around day 6 and a gradual change in the lipid composition during vacuole maturation. Spectral characteristics of intracellular LCV and SCV reveal a higher lipid content of the metabolically active LCV.

Ethoxy acetalated dextran-based nanocarriers accomplish efficient inhibition of leukotriene formation by a novel FLAP antagonist in human leukocytes and blood.

Leukotrienes are pro-inflammatory lipid mediators generated by 5-lipoxygenase aided by the 5-lipoxygenase-activating protein (FLAP). BRP-201, a novel benzimidazole-based FLAP antagonist, inhibits leukotriene biosynthesis in isolated leukocytes. However, like other FLAP antagonists, BRP-201 fails to effectively suppress leukotriene formation in blood, which limits its therapeutic value. Here, we describe the encapsulation of BRP-201 into poly(lactide-co-glycolide) (PLGA) and ethoxy acetalated dextran (Ace-DEX) nanoparticles (NPs), aiming to overcome these detrimental pharmacokinetic limitations and to enhance the bioactivity of BRP-201. NPs loaded with BRP-201 were produced via nanoprecipitation and the physicochemical properties of the NPs were analyzed in-depth using dynamic light scattering (size, dispersity, degradation), electrophoretic light scattering (effective charge), NP tracking analysis (size, dispersity), scanning electron microscopy (size and morphology), UV-VIS spectroscopy (drug loading), an analytical ultracentrifuge (drug release, degradation kinetics), and Raman spectroscopy (chemical attributes). Biological assays were performed to study cytotoxicity, cellular uptake, and efficiency of BRP-201-loaded NPs versus free BRP-201 to suppress leukotriene formation in primary human leukocytes and whole blood. Both PLGA- and Ace-DEX-based NPs were significantly more efficient to inhibit leukotriene formation in neutrophils versus free drug. Whole blood experiments revealed that encapsulation of BRP-201 into Ace-DEX NPs strongly increases its potency, especially upon pro-longed (≥ 5 h) incubations and upon lipopolysaccharide-challenge of blood. Finally, intravenous injection of BRP-201-loaded NPs significantly suppressed leukotriene levels in blood of mice in vivo. These results reveal the feasibility of our pharmacological approach using a novel FLAP antagonist encapsulated into Ace-DEX-based NPs with improved efficiency in blood to suppress leukotriene biosynthesis.

TrkC Is Essential for Nephron Function and Trans-Activates Igf1R Signaling.

BACKGROUND: Injury to kidney podocytes often results in chronic glomerular disease and consecutive nephron malfunction. For most glomerular diseases, targeted therapies are lacking. Thus, it is important to identify novel signaling pathways contributing to glomerular disease. Neurotrophic tyrosine kinase receptor 3 (TrkC) is expressed in podocytes and the protein transmits signals to the podocyte actin cytoskeleton. METHODS: Nephron-specific TrkC knockout (TrkC-KO) and nephron-specific TrkC-overexpressing (TrkC-OE) mice were generated to dissect the role of TrkC in nephron development and maintenance. RESULTS: Both TrkC-KO and TrkC-OE mice exhibited enlarged glomeruli, mesangial proliferation, basement membrane thickening, albuminuria, podocyte loss, and aspects of FSGS during aging. Igf1 receptor (Igf1R)-associated gene expression was dysregulated in TrkC-KO mouse glomeruli. Phosphoproteins associated with insulin, erb-b2 receptor tyrosine kinase (Erbb), and Toll-like receptor signaling were enriched in lysates of podocytes treated with the TrkC ligand neurotrophin-3 (Nt-3). Activation of TrkC by Nt-3 resulted in phosphorylation of the Igf1R on activating tyrosine residues in podocytes. Igf1R phosphorylation was increased in TrkC-OE mouse kidneys while it was decreased in TrkC-KO kidneys. Furthermore, TrkC expression was elevated in glomerular tissue of patients with diabetic kidney disease compared with control glomerular tissue. CONCLUSIONS: Our results show that TrkC is essential for maintaining glomerular integrity. Furthermore, TrkC modulates Igf-related signaling in podocytes.

Interaction of Masitinib with Organic Cation Transporters.

Tyrosine kinase inhibitors (TKI) such as Masitinib were reported to be useful as therapeutic options in malignant disorders and nonmalignant diseases, like coronavirus disease 2019 (COVID-19). Most kinases must be translocated into targeted cells by the action of specific transport proteins, as they are hydrophilic and not able to cross cell membranes freely. Accordingly, the efficacy of TKI in target cells is closely dependent on the expression of their transporters. Specifically, Masitinib is an organic cation and is expected to interact with organic cation transporters (OCT and Multidrug and Toxin Extrusion proteins-MATE-). The aim of this work was to characterize the interaction of Masitinib with different OCTs. Human embryonic kidney 293 cells stably transfected with murine or human OCT were used for the experiments. The interaction of Masitinib with OCTs was investigated using quenching experiments. The intracellular accumulation of this drug was quantified using high performance liquid chromatography. Our results identified interactions of Masitinib with almost all investigated mouse (m) and human (h) OCTs and hMATE1 and indicated OCT1 and hOCT2 to be especially potent Masitinib translocators across cell membranes. Interestingly, some important differences were observed for the interaction with murine and human OCTs. In the future, investigations concerning further in vitro and in vivo properties of Masitinib and its efficacy related to transporter-related uptake mechanisms under pathophysiological conditions should be performed. Clinical trials in humans and other animals with Masitinib have already shown promising results. However, further research is necessary to understand the disease specific transport mechanisms of Masitinib to contribute to a successful and responsible therapy employment.

Pals1 prevents Rac1-dependent colorectal cancer cell metastasis by inhibiting Arf6.

Loss of apical-basal polarity and downregulation of cell-cell contacts is a critical step during the pathogenesis of cancer. Both processes are regulated by the scaffolding protein Pals1, however, it is unclear whether the expression of Pals1 is affected in cancer cells and whether Pals1 is implicated in the pathogenesis of the disease.Using mRNA expression data and immunostainings of cancer specimen, we show that Pals1 is frequently downregulated in colorectal cancer, correlating with poorer survival of patients. We further found that Pals1 prevents cancer cell metastasis by controlling Rac1-dependent cell migration through inhibition of Arf6, which is independent of the canonical binding partners of Pals1. Loss of Pals1 in colorectal cancer cells results in increased Arf6 and Rac1 activity, enhanced cell migration and invasion in vitro and increased metastasis of transplanted tumor cells in mice. Thus, our data reveal a new function of Pals1 as a key inhibitor of cell migration and metastasis of colorectal cancer cells. Notably, this new function is independent of the known role of Pals1 in tight junction formation and apical-basal polarity.

Revisiting the interaction of heme with hemopexin.

In hemolytic disorders, erythrocyte lysis results in massive release of hemoglobin and, subsequently, toxic heme. Hemopexin is the major protective factor against heme toxicity in human blood and currently considered for therapeutic use. It has been widely accepted that hemopexin binds heme with extraordinarily high affinity of <1 pM in a 1:1 ratio. However, several lines of evidence point to a higher stoichiometry and lower affinity than determined 50 years ago. Here, we re-analyzed these data. SPR and UV/Vis spectroscopy were used to monitor the interaction of heme with the human protein. The heme-binding sites of hemopexin were characterized using hemopexin-derived peptide models and competitive displacement assays. We obtained a KD value of 0.32 ± 0.04 nM and the ratio for the interaction was determined to be 1:1 at low heme concentrations and at least 2:1 (heme:hemopexin) at high concentrations. We were able to identify two yet unknown potential heme-binding sites on hemopexin. Furthermore, molecular modelling with a newly created homology model of human hemopexin suggested a possible recruiting mechanism by which heme could consecutively bind several histidine residues on its way into the binding pocket. Our findings have direct implications for the potential administration of hemopexin in hemolytic disorders.

Vibrational Spectroscopic Investigation of Blood Plasma and Serum by Drop Coating Deposition for Clinical Application.

In recent decades, vibrational spectroscopic methods such as Raman and FT-IR spectroscopy are widely applied to investigate plasma and serum samples. These methods are combined with drop coating deposition techniques to pre-concentrate the biomolecules in the dried droplet to improve the detected vibrational signal. However, most often encountered challenge is the inhomogeneous redistribution of biomolecules due to the coffee-ring effect. In this study, the variation in biomolecule distribution within the dried-sample droplet has been investigated using Raman and FT-IR spectroscopy and fluorescence lifetime imaging method. The plasma-sample from healthy donors were investigated to show the spectral differences between the inner and outer-ring region of the dried-sample droplet. Further, the preferred location of deposition of the most abundant protein albumin in the blood during the drying process of the plasma has been illustrated by using deuterated albumin. Subsequently, two patients with different cardiac-related diseases were investigated exemplarily to illustrate the variation in the pattern of plasma and serum biomolecule distribution during the drying process and its impact on patient-stratification. The study shows that a uniform sampling position of the droplet, both at the inner and the outer ring, is necessary for thorough clinical characterization of the patient's plasma and serum sample using vibrational spectroscopy.

Biochemical Analysis of Leukocytes after In Vitro and In Vivo Activation with Bacterial and Fungal Pathogens Using Raman Spectroscopy.

Biochemical information from activated leukocytes provide valuable diagnostic information. In this study, Raman spectroscopy was applied as a label-free analytical technique to characterize the activation pattern of leukocyte subpopulations in an in vitro infection model. Neutrophils, monocytes, and lymphocytes were isolated from healthy volunteers and stimulated with heat-inactivated clinical isolates of Candida albicans, Staphylococcus aureus, and Klebsiella pneumoniae. Binary classification models could identify the presence of infection for monocytes and lymphocytes, classify the type of infection as bacterial or fungal for neutrophils, monocytes, and lymphocytes and distinguish the cause of infection as Gram-negative or Gram-positive bacteria in the monocyte subpopulation. Changes in single-cell Raman spectra, upon leukocyte stimulation, can be explained with biochemical changes due to the leukocyte's specific reaction to each type of pathogen. Raman spectra of leukocytes from the in vitro infection model were compared with spectra from leukocytes of patients with infection (DRKS-ID: DRKS00006265) with the same pathogen groups, and a good agreement was revealed. Our study elucidates the potential of Raman spectroscopy-based single-cell analysis for the differentiation of circulating leukocyte subtypes and identification of the infection by probing the molecular phenotype of those cells.

Analysis of Bacteriophage-Host Interaction by Raman Tweezers.

Bacteriophages, or "phages" for short, are viruses that replicate in bacteria. The therapeutic and biotechnological potential of phages and their lytic enzymes is of interest for their ability to selectively destroy pathogenic bacteria, including antibiotic-resistant strains. Introduction of phage preparations into medicine, biotechnology, and food industry requires a thorough characterization of phage-host interaction on a molecular level. We employed Raman tweezers to analyze the phage-host interaction of Staphylococcus aureus strain FS159 with a virulent phage JK2 (=812K1/420) of the Myoviridae family and a temperate phage 80α of the Siphoviridae family. We analyzed the timeline of phage-induced molecular changes in infected host cells. We reliably detected the presence of replicating phages in bacterial cells within 5 min after infection. Our results lay the foundations for building a Raman-based diagnostic instrument capable of real-time, in vivo, in situ, nondestructive characterization of the phage-host relationship on the level of individual cells, which has the potential of importantly contributing to the development of phage therapy and enzybiotics.

Detection and Differentiation of Bacterial and Fungal Infection of Neutrophils from Peripheral Blood Using Raman Spectroscopy.

Neutrophils are important cells of the innate immune system and the major leukocyte subpopulation in blood. They are responsible for recognizing and neutralizing invading pathogens, such as bacteria or fungi. For this, neutrophils are well equipped with pathogen recognizing receptors, cytokines, effector molecules, and granules filled with reactive oxygen species (ROS)-producing enzymes. Depending on the pathogen type, different reactions are triggered, which result in specific activation states of the neutrophils. Here, we aim to establish a label-free method to indirectly detect infections and to identify the cause of infection by spectroscopic characterization of the neutrophils. For this, isolated neutrophils from human peripheral blood were stimulated in an in vitro infection model with heat-inactivated Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial pathogens as well as with heat-inactivated and viable fungi (Candida albicans). Label-free and nondestructive Raman spectroscopy was used to characterize neutrophils on a single cell level. Phagocytized fungi could be visualized in a few high-resolution false color images of individual neutrophils using label-free Raman spectroscopic imaging. Using a high-throughput screening Raman spectroscope (HTS-RS), Raman spectra of more than 2000 individual neutrophils from three different donors were collected in each treatment group, yielding a data set of almost 20 000 neutrophil spectra. Random forest classification models were trained to differentiate infected and noninfected cells with high accuracy (90%). Among the neutrophils challenged with pathogens, even the cause of infection, bacterial or fungal, was predicted correctly with 92% accuracy. Therefore, Raman spectroscopy enables reliable neutrophil phenotyping and infection diagnosis in a label-free manner. In contrast to the microbiological diagnostic standard, where the pathogen is isolated in time-consuming cultivation, this Raman-based method could potentially be blood-culture independent, thus saving precious time in bloodstream infection diagnostics.

Comparability of Raman Spectroscopic Configurations: A Large Scale Cross-Laboratory Study.

The variable configuration of Raman spectroscopic platforms is one of the major obstacles in establishing Raman spectroscopy as a valuable physicochemical method within real-world scenarios such as clinical diagnostics. For such real world applications like diagnostic classification, the models should ideally be usable to predict data from different setups. Whether it is done by training a rugged model with data from many setups or by a primary-replica strategy where models are developed on a 'primary' setup and the test data are generated on 'replicate' setups, this is only possible if the Raman spectra from different setups are consistent, reproducible, and comparable. However, Raman spectra can be highly sensitive to the measurement conditions, and they change from setup to setup even if the same samples are measured. Although increasingly recognized as an issue, the dependence of the Raman spectra on the instrumental configuration is far from being fully understood and great effort is needed to address the resulting spectral variations and to correct for them. To make the severity of the situation clear, we present a round robin experiment investigating the comparability of 35 Raman spectroscopic devices with different configurations in 15 institutes within seven European countries from the COST (European Cooperation in Science and Technology) action Raman4clinics. The experiment was developed in a fashion that allows various instrumental configurations ranging from highly confocal setups to fibre-optic based systems with different excitation wavelengths. We illustrate the spectral variations caused by the instrumental configurations from the perspectives of peak shifts, intensity variations, peak widths, and noise levels. We conclude this contribution with recommendations that may help to improve the inter-laboratory studies.

Vibrational spectroscopy as a powerful tool for follow-up immunoadsorption therapy treatment of dilated cardiomyopathy - a case report.

Dilated cardiomyopathy (DCM) is a leading cardiomyopathy condition and is the leading reason for heart transplantation. Due to high etiologic and genetic heterogeneity of the pathologies, different therapeutic treatment strategies are available and have been successful for different treatments. Immunoadsorption (IA) therapy removes the circulating anticardiac antibodies and improves the left ventricular function in substantial proportion of DCM patients. Powerful, non-invasive analytical tools are highly desired to investigate the efficiency and success of IA therapy. In this contribution, we followed the changes of a female DCM patient undergoing IA therapy at different treatment time points in a label-free, non-invasive manner from blood samples (plasma and serum) on the basis of vibrational spectroscopy (Raman scattering and IR absorption). Chemometric methods, including dimension reduction and statistical modeling, were used to interpret spectral data. The impact of different time points of the IA treatment can be identified in both the plasma and serum, using both techniques, with high accuracy. The removal of antibodies of immunoglobulin G (IgG) group during IA therapy and their restoration was reflected in both Raman and FTIR spectra. Relative changes in the spectral bands assigned to IgG agreed well with the immunoturbidimetry measurement of total IgG. Successful clinical treatment was accompanied by spectral differences between vibrational spectra obtained at initial disease state and 11 months after the IA treatment. The long-term follow-up of the patient reveals the stabilization of the health state after therapy. It is noteworthy that the treatment time points were distinguished with a better accuracy using spectra from plasma compared to those from serum samples, which might indicate the involvement of corresponding proteins in the coagulation. Vibrational spectroscopy is a powerful tool for personalized medicine to follow-up the treatment success of IA therapy for the DCM disorder.

Two-Photon-Induced CO-Releasing Molecules as Molecular Logic Systems in Solution, Polymers, and Cells.

Phototherapeutic applications of carbon monoxide (CO)-releasing molecules are limited because they require harmful UV and blue light for activation. We describe two-photon excitation with NIR light (800 nm)-induced CO-release from two MnI tricarbonyl complexes bearing 1,8-naphthalimide units (1, 2). Complex 2 behaves as a logic OR gate in solution, nonwovens, and in HeLa cells. CO release, indicated by fluorescence enhancement, was detected in solution, nonwoven, and HeLa cells by single- (405 nm) and two-photon (800 nm) excitation. The photophysical properties of 1 and 2 have been measured and supported by DFT and TDDFT quantum chemical calculations. Both photoCORMs are stable in the dark in solution and noncytotoxic, leading to promising applications as phototherapeutics with NIR light.