There is a risk of crimes remaining unsolved when no matching DNA profiles or fingermarks are found. If this is the case, forensic investigations are faced with a significant shortage of evidence and ...information regarding the unknown perpetrator and/or victim as well as any missing persons. However, a rather commonly found biological trace encountered at crime scenes is human hair. As hair acts as a biochemical reservoir, it may contain valuable information regarding one’s characteristics and habits. This study aimed to build an analytical method capable of determining a marker set of relevant metabolites in hair, eventually building up a profile of its donor. To find potential markers, an untargeted metabolomics approach was developed to select and identify statistically significant features. For that purpose, a total of 68 hair samples were collected at several hairdresser shops in varying neighbourhoods. Compound extraction was achieved via methanolic incubation overnight and analysis performed using a high-resolution mass spectrometry (HRMS) Orbitrap Q Exactive Focus. The acquired data was uploaded and statistically evaluated using two free online software/libraries, where a total of eight compounds have given a match on both tools. Their presumptive identity was confirmed using reference standards and consequently added to a dynamic target donor profiling list. These results show the potential of using untargeted metabolomics for the search for lifestyle biomarkers capable of differentiating individuals. Such tools are of paramount importance in a forensic setting with little or no evidence available and no clear tactical leads.
•An untargeted metabolomics method was developed to aid evidence-scarce cases.•Hair proves to be an efficient forensic reservoir for one’s lifestyle.•A pioneering untargeted approach was used to unravel biomarkers in hair.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The liver is the primary organ involved in handling of bile salts, a class of amphipathic molecules with signaling activities as well as desired and detrimental detergent actions. To allow in-depth ...investigation of functions of bile salts in healthy and diseased liver, the spatial distribution of bile salt species within the liver needs to be studied. Therefore, the aim of our study was to determine hepatic bile salt distribution and identify specific lipid markers that define the structural elements of the liver. Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) was used to monitor the spatial distribution of bile salts and lipids in liver sections of rat, dog, and patients with unaffected and cholestatic parenchyma. MALDI-MSI in negative ion mode showed the local presence of a variety of bile salts, predominantly taurine-conjugates, as localized patches of varying sizes (representing the bile ducts) throughout the liver tissue. Specific molecular markers were identified for the connective tissue (phosphatidic acids, e.g., PA (18:0_18:1)–H−), the liver parenchyma (phosphatidylinositols, e.g., PI (18:0_20:4)-H−), and the bile ducts (hydroxylated-sulfatides, e.g., ST–OH (18:1_24:0)-H−). One of these sulfatides (at m/z 906.6339) was found to be uniquely localized in a thin lining on the inside of the bile duct, colocalized with cytokeratins, and encased luminal bile salts. A similar distribution of the aforementioned sulfatide was observed, albeit in constricted ductular structures, in the liver of a patient with a mild clinical phenotype of primary sclerosing cholangitis (PSC). In contrast, sulfatides were virtually absent in the liver of patients with PSC and a severe clinical phenotype, with (atypical) cholanoids (e.g., the bile alcohol 5-cyprinolsulfate) abundant in the extra-ductular space and glyco(cheno)deoxycholic acid-3-sulfate localized to fibrotic connective tissue. The latter two molecular species were able to discriminate between healthy liver tissue (n = 3) and tissue from PSC patients with a severe clinical phenotype (n = 3). In conclusion, the distinct structural elements of the mammalian liver are characterized by specific classes of lipids. We propose that (hydroxylated-)sulfatides are specific molecular markers of the bile duct.
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IJS, KILJ, NUK, PNG, UL, UM
The discovery of novel pathogenic mechanisms engaged during bacterial infections requires the evolution of advanced techniques. Here, we evaluate the dual polarity matrix norharmane (NRM) to improve ...detection of bacterial lipid A (endotoxin), from host and vector tissues infected with Francisella novicida (Fn). We evaluated NRM for improved detection and characterization of a wide range of lipids in both positive and negative polarities, including lipid A and phospholipids across a range of matrix-assisted laser desorption-ionization-coupled applications. NRM matrix improved the limit of detection (LOD) for monophosphoryl lipid A (MPLA) down to picogram level representing a 10-fold improvement of LOD versus 2,5-dihydroxybenzoic acid and 100-fold improvement of LOD versus 9-aminoacridine (9-AA). Improved LOD for lipid A subsequently facilitated detection of the Fn lipid A major ion (m/z 1665) from extracts of infected mouse spleen and the temperature-modified Fn lipid A at m/z 1637 from infected Dermacentor variabilis ticks. Finally, we simultaneously mapped bacterial phospholipid signatures within an Fn-infected spleen along with an exclusively host-derived inositol-based phospholipid (m/z 933) demonstrating coprofiling of the host–pathogen interaction. Expanded use of NRM matrix in other infection models and endotoxin-targeting imaging experiments will improve our understanding of the lipid interactions at the host–pathogen interface.
This study presents a versatile tool for host–pathogen interaction studies by mass spectrometry imaging; we emphasize the improved detection of pathogen-specific lipids (endotoxin) achievable only with norharmane (NRM), an underutilized matrix substance facilitating simultaneous detection of host and pathogen lipids.
Highlights • MSI is useful tool in studying the effect of cosmetic treatment on cocaine in hair. • Bleaching hair peroxide decreases the detectability of cocaine in user hair. • Melanin–cocaine bonds ...are broken and cocaine is degraded into reaction products. • Unbound cocaine and reaction products are washed out removing evidence of cocaine use.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Mass spectrometry imaging (MSI) is a label free technique capable of providing simultaneous identification and localization of biomolecules. A multimodal approach is required that allows for the ...study of the complexity of biological tissue samples to overcome the limitations of a single MSI technique. Secondary ion mass spectrometry (SIMS) allows for high spatial resolution imaging while matrix-assisted laser desorption (MALDI) offers a significantly wider mass range. The combination of coregistered SIMS and MALDI images results in detailed and unique biomolecular information. In this Technical Note, we describe how gold sputtered/implanted fiducial markers (FM) are created and can be used to ensure a proper overlay and coregistration of the two-dimensional images provided by the two MSI modalities.
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IJS, KILJ, NUK, PNG, UL, UM
In order to assess the potential of matrix-assisted laser desorption mass spectrometry imaging for the examination of artificial skin models, the absorption of the tricyclic antidepressant imipramine ...into Straticell-RHE-EPI/001 an artificial model of the human epidermis has been studied.
The presence of imipramine could be clearly discerned in treated samples by imaging the distribution of the protonated molecule at m/z 281.18 in samples taken 2 and 8 h after treatment.
No clear evidence of biotransformation of imipramine in the artificial epidermal model was detected, although some signals that could potentially be assigned to the desmethyl metabolite were detected. Further work is required in order to investigate the reasons for the apparent low levels of metabolites detected.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Whilst it might be desirable to be able to purchase an up to date mass spectrometry platform and dedicate it to mass spectrometry imaging, this is not the situation initially for many laboratories. ...There are a variety of methods by which existing mass spectrometers can be upgraded/adapted to perform mass spectrometry imaging using MALDI, DESI or LAESI as the means of generating ions. The focus of this article is on relatively low cost adaptations of existing instrumentation with suggestions made for performance enhancements where appropriate. A brief description of attempts to perform SIMS imaging on quadrupole time of flight mass spectrometers is also given. The required software is described with particular emphasis on freeware packages which can be used to display/enhance data. Requirements for data pre-processing prior or statistical analysis are discussed along with the use of MATLAB® for the analysis itself.
This article is part of a Special Issue entitled: Imaging Mass Spectrometry: A User’s Guide to a New Technique for Biological and Biomedical Research.
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► Methods for Upgrading/Converting Existing MS Instrumentation for MS Imaging are described. ► Freely available software for the generation and processing of MS Images is described. ► Software for pre and post processing of MS imaging data is described and suggestions made for its optimum use.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Matrix-assisted laser desorption/ionisation-mass spectrometry imaging (MALDI-MSI) has been extensively applied to monitoring the distribution of pharmaceutical compounds in tissues. The main aim of ...the work reported in this thesis is to monitor the distribution of respiratory compounds in the lungs following inhaled delivery.Glucocorticoids that contain multiple carbonyl functionalities are not easily protonated/de-protonated to form charged species due to the poor ionisation efficiencies of the carbonyl functionalities. Derivatisation with hydrazine based reagents has been proposed as a solution to this problem. These reagents have been employed for the in-solution and on-tissue derivatisation of a range of glucocorticoids to form their respective hydrazones improving their mass spectral ionisation efficiency and detection.MALDI-MSI has been used to screen a set of respiratory compounds in order to determine their on-tissue limit of detection. The distribution of a Tiotropium Bromide was monitored throughout the lungs following inhaled delivery. High spatial resolution imaging enabled a detailed view of the distribution of Tiotropium in the trachea and major airways.Quantitative mass spectrometry imaging is a new field that has recently gained a lot of attention especially in pharmaceutical research. The ability to obtain quantitative information as well as the distribution of pharmaceutical compounds and associated metabolites offers a distinct advantage over traditional quantitative methods such as LC-MS/MS and QWBA. The current methods of generating quantification information from MALDI-MS images has been evaluated, which let development of a method for the preparation of standards for use in the quantification of drugs in tissue sections.MALDI-MSI has been used to acquire data from serial sections obtained at equal intervals through control mouse lung tissue, homogenate registration markers were incorporated in order to aid the final 3D image construction. Using two 3D imaging software packages were used to reconstruct the images were stacked together to enable the 3D distribution of a particular endogenous species throughout the lungs to be displayed.
Matrix-assisted laser desorption/ionisation-mass spectrometry imaging (MALDI-MSI) has been extensively applied to monitoring the distribution of pharmaceutical compounds in tissues. The main aim of ...the work reported in this thesis is to monitor the distribution of respiratory compounds in the lungs following inhaled delivery. Glucocorticoids that contain multiple carbonyl functionalities are not easily protonated/de-protonated to form charged species due to the poor ionisation efficiencies of the carbonyl functionalities. Derivatisation with hydrazine based reagents has been proposed as a solution to this problem. These reagents have been employed for the in-solution and on-tissue derivatisation of a range of glucocorticoids to form their respective hydrazones improving their mass spectral ionisation efficiency and detection. MALDI-MSI has been used to screen a set of respiratory compounds in order to determine their on-tissue limit of detection. The distribution of a Tiotropium Bromide was monitored throughout the lungs following inhaled delivery. High spatial resolution imaging enabled a detailed view of the distribution of Tiotropium in the trachea and major airways. Quantitative mass spectrometry imaging is a new field that has recently gained a lot of attention especially in pharmaceutical research. The ability to obtain quantitative information as well as the distribution of pharmaceutical compounds and associated metabolites offers a distinct advantage over traditional quantitative methods such as LC-MS/MS and QWBA. The current methods of generating quantification information from MALDI-MS images has been evaluated, which let development of a method for the preparation of standards for use in the quantification of drugs in tissue sections. MALDI-MSI has been used to acquire data from serial sections obtained at equal intervals through control mouse lung tissue, homogenate registration markers were incorporated in order to aid the final 3D image construction. Using two 3D imaging software packages were used to reconstruct the images were stacked together to enable the 3D distribution of a particular endogenous species throughout the lungs to be displayed.
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