Mass Spectrometry Imaging of Biomaterials.

The science related to biomaterials and tissue engineering accounts for a growing part of our knowledge. Surface modifications of biomaterials, their performance in vitro, and the interaction between them and surrounding tissues are gaining more and more attention. It is because we are interested in finding sophisticated materials that help us to treat or mitigate different disorders. Therefore, efficient methods for surface analysis are needed. Several methods are routinely applied to characterize the physical and chemical properties of the biomaterial surface. Mass Spectrometry Imaging (MSI) techniques are able to measure the information about molecular composition simultaneously from biomaterial and adjacent tissue. That is why it can answer the questions connected with biomaterial characteristics and their biological influence. Moreover, this kind of analysis does not demand any antibodies or dyes that may influence the studied items. It means that we can correlate surface chemistry with a biological response without any modification that could distort the image. In our review, we presented examples of biomaterials analyzed by MSI techniques to indicate the utility of SIMS, MALDI, and DESI-three major ones in the field of biomaterials applications. Examples include biomaterials used to treat vascular system diseases, bone implants with the effects of implanted material on adjacent tissues, nanofibers and membranes monitored by mass spectrometry-related techniques, analyses of drug-eluting long-acting parenteral (LAPs) implants and microspheres where MSI serves as a quality control system.

Hemorphins-From Discovery to Functions and Pharmacology.

During the last three decades, a variety of different studies on bioactive peptides that are opioid receptor ligands, have been carried out, with regard to their isolation and identification, as well as their molecular functions in living organisms. Thus, in this review, we would like to summarize the present state-of-the art concerning hemorphins, methodological aspects of their identification, and their potential role as therapeutic agents. We have collected and discussed articles describing hemorphins, from their discovery up until now, thus presenting a very wide spectrum of their characteristic and applications. One of the major assets of the present paper is a combination of analytical and pharmacological aspects of peptides described by a team who participated in the initial research on hemorphins. This review is, in part, focused on the analysis of endogenous opioid peptides in biological samples using advanced techniques, description of the identification of synthetic/endogenous hemorphins, their involvement in pharmacology, learning, pain and other function. Finally, the part regarding hemorphin analogues and their synthesis, has been added.

LVV-hemorphin-7 (LVV-H7) plays a role in antinociception in a rat model of alcohol-induced pain disorders.

Alcohol can increase the sensitivity to painful stimulation or convert insensibility to pain at different stages. We hypothesized that chronic alcohol consumption changes the level of LVV-hemorphin-7 (abbreviated as LVV-H7, an opioid-like peptide generated from hemoglobin ß-chain), thereby affecting pain sensation. We established a chronic alcohol-exposed rat model to investigate the effects of LVV-H7. Adult male Sprague-Dawley rats were subjected to daily intraperitoneal injection of 10 % ethanol (w/v) at 0.5 g/kg for 15 days and subsequent alcohol withdrawal for 5 days. Using different pharmacological strategies to affect the LVV-H7 level, we investigated the correlation between LVV-H7 and pain-related behavior. Tail-flick and hot plate tests were employed to investigate alcohol-induced pain-related behavioral changes. The serum level of LVV-H7 was determined by ELISA. Our results showed that alcohol first induced an analgesia followed by a hyperalgesia during alcohol withdrawal, which could be driven by the quantitative change of LVV-H7. A positive correlation between the level of LVV-H7 and Δtail-flick latency (measured latency minus basal latency) confirmed this finding. Moreover, we revealed that the LVV-H7 levels were determined by the activity of cathepsin D and red blood cell/hemoglobin counts, which could be affected by alcohol. These results suggest that the deterioration of anti-nociception induced by alcohol is correlated to the decreased level of LVV-H7, and this could be due to alcohol-induced anemia. This study may help to develop LVV-H7 structure-based novel analgesics for treating alcohol-induced pain disorders and thus ameliorate the complications in alcoholics.

Changes in Protein Glycosylation as a Result of Aptamer Interactions with Cancer Cells.

PURPOSE: Based on the recent aptamer-related breast cancer studies, which indicate the therapeutic role of specific oligonucleotide sequences, experiments have been designed in an attempt to unravel the molecular targets of this mechanism. This article describes the study on glycoproteome changes in breast cancer cells as a result of their interactions with aptamers. EXPERIMENTAL DESIGN: Aberrations in protein glycosylation play an important role in tumorigenesis and influence cancer progression, metastasis, immunoresponse, and chemoresistance, therefore this study is focused on the identification of the alterations in glycan expression on the surface of proteins as a potential and innovative tool for biomedical applications of aptamers in cancer treatment. RESULTS: Two proteins, kinesin-like protein (KI13B) and proliferating cell nuclear antigen (PCNA), have been identified that carry N-glycan epitopes after conjugation with aptamer sequences. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple features of aptamers as an alternative to protein antibodies are utilized for various biomedical applications ranging from biomarker discovery, bioimaging, targeted therapy, drug delivery, and drug pharmacokinetics and biodistribution. Frequently, aptamers bind to their target molecules and modulate their function. Such therapeutic aptamers can modify the biological pathways for treatment of many types of diseases, such as cancer.

Morphinome Database - The database of proteins altered by morphine administration - An update.

Morphine is considered a gold standard in pain treatment. Nevertheless, its use could be associated with severe side effects, including drug addiction. Thus, it is very important to understand the molecular mechanism of morphine action in order to develop new methods of pain therapy, or at least to attenuate the side effects of opioids usage. Proteomics allows for the indication of proteins involved in certain biological processes, but the number of items identified in a single study is usually overwhelming. Thus, researchers face the difficult problem of choosing the proteins which are really important for the investigated processes and worth further studies. Therefore, based on the 29 published articles, we created a database of proteins regulated by morphine administration - The Morphinome Database (addiction-proteomics.org). This web tool allows for indicating proteins that were identified during different proteomics studies. Moreover, the collection and organization of such a vast amount of data allows us to find the same proteins that were identified in various studies and to create their ranking, based on the frequency of their identification. STRING and KEGG databases indicated metabolic pathways which those molecules are involved in. This means that those molecular pathways seem to be strongly affected by morphine administration and could be important targets for further investigations. SIGNIFICANCE: The data about proteins identified by different proteomics studies of molecular changes caused by morphine administration (29 published articles) were gathered in the Morphinome Database. Unification of those data allowed for the identification of proteins that were indicated several times by distinct proteomics studies, which means that they seem to be very well verified and important for the entire process. Those proteins might be now considered promising aims for more detailed studies of their role in the molecular mechanism of morphine action.

Glycopeptides as a Tool for Early Detection of Cancer.

Protein glycosylation, as one of the most common and complex posttranslational modifications, plays an important role in many biological processes. Along with the intensive progress in MS techniques and development of glycan search tools and databases, glycoproteomics has become a popular subject of studies. The possibility of simultaneous identification of amino acid sequence, glycosylation sites, and glycan composition enabled the monitoring of changes in glycosylation patterns in various pathological states. In this issue, Saraswat et al. describe MS-based investigations of glycopeptide changes in oral cavity squamous cell carcinoma (OSCC). Their findings indicate glycopeptides with changed expression levels and the presence of altered glycan forms observed in four proteins derived from OSCC patients' sera. Proteins carrying this distinctive pattern are in the group of the most abundant components of serum, IgG1, IgG4, HPT, and TRFE, which makes their identification more accessible. Described changes, characteristic for cancer serum samples, may be considered as potential diagnostic indicators of OSCC; however, there is still a need to establish a universal glycopeptide-based biomarkers database, where all glycoproteomic data can be collected from all types of cancer studies and evaluated using meta-analyses. Only then, early diagnosis of patients using MS-based approach will make sense, as those investigations are very convoluted, and all efforts made during sample preparation and analysis will pay off when comprehensive anticancer prevention will be achieved during single measurement.

Advances in the Study of Aptamer-Protein Target Identification Using the Chromatographic Approach.

Ever since the development of the process known as the systematic evolution of ligands by exponential enrichment (SELEX), aptamers have been widely used in a variety of studies, including the exploration of new diagnostic tools and the discovery of new treatment methods. Aptamers' ability to bind to proteins with high affinity and specificity, often compared to that of antibodies, enables the search for potential cancer biomarkers and helps us understand the mechanisms of carcinogenesis. The blind spot of those investigations is usually the difficulty in the selective extraction of targets attached to the aptamer. There are many studies describing the cell SELEX for the prime choice of aptamers toward living cancer cells or even whole tumors in the animal models. However, a dilemma arises when a large number of proteins are being identified as potential targets, which is often the case. In this article, we present a new analytical approach designed to selectively target proteins bound to aptamers. During studies, we have focused on the unambiguous identification of the molecular targets of aptamers characterized by high specificity to the prostate cancer cells. We have compared four assay approaches using electrophoretic and chromatographic methods for "fishing out" aptamer protein targets followed by mass spectrometry identification. We have established a new methodology, based on the fluorescent-tagged oligonucleotides commonly used for flow-cytometry experiments or as optic aptasensors, that allowed the detection of specific aptamer-protein interactions by mass spectrometry. The use of atto488-labeled aptamers for the tracking of the formation of specific aptamer-target complexes provides the possibility of studying putative protein counterparts without needing to apply enrichment techniques. Significantly, changes in the hydrophobic properties of atto488-labeled aptamer-protein complexes facilitate their separation by reverse-phase chromatography combined with fluorescence detection followed by mass-spectrometry-based protein identification. These comparative results of several methodological approaches confirmed the universal applicability of this method to studying aptamer-protein interactions with high sensitivity, showing superior properties compared with pull-down techniques.

Brain lipidomic changes after morphine, cocaine and amphetamine administration - DESI - MS imaging study.

Drug addiction is a complex disorder, evoking significant changes in the proteome of the central nervous system. To check if there are also changes in the lipidomic profiles we used desorption electrospray-MS technique for imaging of the brain slices of rats exposed to morphine, cocaine and amphetamine. Our investigations showed alternative regulation of selected lipid's levels in the central nervous system structures, under the influence of applied drugs. Results of our investigations can show changes in the brain treated with drugs of abuse in the new light, indicating role of the lipids in the addiction development.

Glycosylation Changes in Serum Proteins Identify Patients with Pancreatic Cancer.

After more than a decade of biomarker discovery using advanced proteomic and genomic approaches, very few biomarkers have been involved in clinical diagnostics. Most candidate biomarkers are focused on the protein component. Targeting post-translational modifications (PTMs) in combination with protein sequences will provide superior diagnostic information with regards to sensitivity and specificity. Glycosylation is one of the most common and functionally important PTMs. It plays a central role in many biological processes, including protein folding, host-pathogen interactions, immune response, and inflammation. Cancer-associated aberrant glycosylation has been identified in various types of cancer. Expression of cancer-specific glycan epitopes represents an excellent opportunity for diagnostics and potentially specific detection of tumors. Here, we report four proteins (LIFR, CE350, VP13A, HPT) found in sera from pancreatic cancer patients carrying aberrant glycan structures as compared to those of controls.

Prevalence and correlates of somatoform disorders in the elderly: Results of a European study.

Somatoform disorders have rarely been addressed in epidemiological and health care services studies of the elderly. The few existing studies vary considerably in their methodologies limiting comparability of findings. Data come from the MentDis_ICF65+ study, in which a total of 3142 community-dwelling respondents aged 65-84 years from six different countries were assessed by the Composite International Diagnostic Interview adapted to the needs of the elderly (CIDI65+). The 12-month prevalence rate for any somatoform disorders was found to be 3.8, whereby the prevalence for somatization disorder according to DSM-IV was 0%, the prevalence for abridged somatization was 1.7% and the rate for 12-months somatoform pain disorder was 2.6%. We found a significant variation by study centre (p < 0.005). There was a significant gender difference for pain disorder, but not for abridged somatization. Significant age-related effects revealed for both disorder groups. Somatoform disorders were found to be associated with other mental disorders [odds ratio (OR) anxiety =4.8, OR affective disorders 3.6], as well as with several impairments and disabilities. Somatoform disorders are prevalent, highly impairing conditions in older adults, which are often associated with other mental disorders and should receive more research and clinical attention.

Comparison of two freely available software packages for mass spectrometry imaging data analysis using brains from morphine addicted rats.

Data analysis from mass spectrometry imaging (MSI) imaging experiments is a very complex task. Most of the software packages devoted to this purpose are designed by the mass spectrometer manufacturers and, thus, are not freely available. Laboratories developing their own MS-imaging sources usually do not have access to the commercial software, and they must rely on the freely available programs. The most recognized ones are BioMap, developed by Novartis under Interactive Data Language (IDL), and Datacube, developed by the Dutch Foundation for Fundamental Research of Matter (FOM-Amolf). These two systems were used here for the analysis of images received from rat brain tissues subjected to morphine influence and their capabilities were compared in terms of ease of use and the quality of obtained results.

Protocol: MYTHBUSTERS: a universal procedure for sample preparation for mass spectrometry.

Improvements in proteomic strategies from the development of new and robust separation and identification techniques have led to broad applications of proteomics to solve numerous biological questions. For all analyses, sample quality is unquestionably a critical factor; therefore protein extraction is of outmost importance. The ideal extraction method should provide reproducible spectra of the most comprehensive repertoire of proteins, while minimizing sample loss and degradation. It is already known that to capture the whole proteome is an unenforceable task. Many protein extraction protocols have been described, yet there is no "one perfect procedure" taking into account the vast diversity of biological and physical properties of proteins, including their charge, size, hydrophobicity, interactions and sub-cellular localization. The research presented here reflects the main obstacle occurring in proteomic experimental design; i.e. the lack of reproducibility as a result of alterations in protein extraction methods. We have performed a series of experiments, aimed towards identification of the aptamer-binding partners in cancerous cells. Aptamers are chemically synthesized, short, single-stranded nucleic acids with a strictly defined three-dimensional structure, which allows them to interact with a target molecule with high affinity. The low immunogenicity and cellular- targeting properties of aptamers might facilitate design of suitable drugs with low side-effects. Aptamers can be used for identification of molecules associated with a pathogenic state of a cell. Aptamers can be considered as a powerful tool, since they possess unique properties to benefit cancer diagnosis, prevention and treatment. We have used different types of protein extraction methods prior to analyses of complex biological samples by mass spectrometry, based on slight changes of homogenization buffers, and have observed the changes in the identified compounds. These results should prove to be very useful for future proteomic studies and the design of studies in terms of sample preparation, especially sample homogenization and protein extraction.

Desorption electrospray ionization-based imaging of interaction between vascular graft and human body.

The desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) is known as a fast and convenient MS-based method for lipid imaging in various biological materials. Here, we applied this technique to visualize lipid distribution in a vascular graft removed from a patient's body. This is a good example of the DESI system capabilities toward imaging of interaction between artificial material and living tissues. Detailed analysis allowed for visualization of the spatial distribution of selected lipids in this implanted, artificial material. Not only DESI-MSI allowed visualization of lipid distribution in the investigated material but also enabled identification of the detected molecular species using MS/MS. Here, this technique was successfully used to evaluate the saturation and spatial distribution of endogenous lipids in the artificial vascular graft. Unambiguous identification of the lipids was done with the aid of fragmentation procedure. We also showed that various lipids localize preferably in graft material or internal plaque existing inside the graft.

Prospective biomechanical evaluation of donor site morbidity after radial forearm free flap.

Although the radial forearm free flap (RFF) is a commonly-used microvascular flap for orofacial reconstruction, we are aware of few prospective biomechanical studies of the donor site. We have therefore evaluated the donor site morbidity biomechanically of 30 consecutive RFF for orofacial reconstruction preoperatively and three months postoperatively. This included the Mayo wrist score, the Disabilities of the Arm, Shoulder and Hand (DASH) score, grip strength, followed by tip pinch, key pinch, palmar pinch, and range of movement of the wrist. Primary defects were all closed with local full-thickness skin grafts from the donor site forearm, thereby circumventing the need for a second defect. Postoperative functional results showed that there was a reduction in hand strength measured by (grip strength: -24.1%, in tip pinch: -23.3%, in key pinch: -16.5, and in palmar pinch: -19.3%); and wrist movement measured by extension (active=14.3% / passive= -11.5%) and flexion = -14.8% / -8.9%), and radial (-9.8% / -9.8%) and ulnar (-11.0% / -9.3%) abduction. The Mayo wrist score was reduced by 9.4 points (-12.9%) and the DASH score increased by 16.1 points (+35.5%) compared with the same forearm preoperatively. The local skin graft resulted in a robust wound cover with a good functional result. Our results show that the reduction in hand strength and wrist movement after harvest of a RFF is objectively evaluable, and did not reflect the subjectively noticed extent and restrictions in activities of daily living. Use of a local skin graft avoids a second donor site and the disadvantages of a split-thickness skin graft.

Increased perfusion in normal appearing white matter in high inflammatory multiple sclerosis patients.

PURPOSE: Although cerebral perfusion alterations have long been acknowledged in multiple sclerosis (MS), the relationship between measurable perfusion changes and the status of highly active MS has not been examined. We hypothesized that alteration of perfusion can be detected in normal appearing white matter and is increased in high inflammatory patients. MATERIALS AND METHODS: Thirty-three patients with relapsing-remitting MS underwent four monthly 3T MRI scans including dynamic susceptibility contrast perfusion-weighted MRI. Cerebral blood flow (CBF) and cerebral blood volume (CBV) were measured in normal appearing white matter. Patients were stratified in a high- and low-inflammatory group according to the number of new contrast enhancing lesions. RESULTS: Thirteen patients were classified as high-inflammatory. Compared to low-inflammatory patients, the high-inflammatory group demonstrated significantly higher CBV (p = 0.001) and CBF (p = 0.014) values. A mixed model analysis to assess independent variables associated with CBV and CBF revealed that white matter lesion load and atrophy measurements had no significant influence on CBF and CBV. CONCLUSION: This work provides evidence that high inflammatory lesion load is associated with increased CBV and CBF, underlining the role of global modified microcirculation prior to leakage of the blood-brain barrier in the pathophysiology of MS. Perfusion changes might therefore be sensitive to active inflammation apart from lesion development without local blood-brain barrier breakdown, and could be utilized to further assess the metabolic aspect of current inflammation.

Surgical complications after kidney transplantation: different impacts of immunosuppression, graft function, patient variables, and surgical performance.

The population of kidney transplant (KTx) recipients often has complex medical and immunological conditions. Surgical complications (SCs) contribute to the increasing morbidity and costs in these patients. We analyzed the risk factors for SC in 405 KTx patients treated using defined immunosuppressive regimens according to their clinical and immunological risk profile: (1) standard immunosuppression (SIS) with IL-2 receptor mAb, CNI, and (a) mycophenolic acid (MPA) or (b) mTOR inhibitor; and (2) more intense immunosuppression (IIS) with (a) ATG or (b) the additional use of plasma exchange and B- and T-cell-depleting agents. In a mixed effects logistic regression model, we identified the following risk factors for SC: male gender, diabetes, and post-operative dialysis. No difference was found between the patients who received SIS with MPA and those who received mTOR inhibitors. The risk of suffering complications with IIS increases with age. In addition to IIS, diabetes was a risk for wound healing disorders. Therapeutic anticoagulation and a third or subsequent retransplantation increased the rate of bleeding. We did not identify immunosuppression or patient demographics as risk factors for lymphoceles or ureter complications; however, we demonstrated that the surgeon had a significant impact on severe complications, especially those of the ureter.

Current primary care management of children aged 1-36 months with urinary tract infections in Europe: large scale survey of paediatric practice.

OBJECTIVE: To describe current practice among European paediatricians regarding diagnosis and management of urinary tract infections in children aged 1-36 months and to compare these practices with recently published guidelines. DESIGN: Web-based large scale survey evaluating knowledge of, attitudes towards and the methods for diagnosing, treating and managing urinary tract infections in children. SETTING: Primary and secondary care practices in Europe. SAMPLE: 1129 paediatricians. RESULTS: A diagnosis of urinary tract infection is considered by 62% of the respondents in children aged 1-36 months with unexplained fever. The preferred method of urine collection is use of a bag (53% for infants <3 months and 59% for children 4-36 months of age). 60% of paediatricians agree that oral and parenteral antibiotics have equal efficacy. Co-amoxiclav is the antibiotic of choice for 41% of participants, while 9% prescribe amoxicillin. 80% of respondents prescribe ultrasound in all children with a confirmed urinary tract infection. 63% of respondents prescribe a cystography when abnormalities are revealed during ultrasound evaluation. A quarter of respondents recommend antibiotic prophylaxis for all children with any vesicoureteral reflux. The data among European countries are very heterogeneous. The three most recent urinary tract infection guidelines (the National Institute for Health and Care Excellence (NICE), the American Academy of Paediatrics and the Italian Society of Paediatric Nephrology) are not followed properly. CONCLUSIONS: Management of febrile urinary tract infections remains controversial and heterogeneous in Europe. Simple, short, practical and easy-to-remember guidelines and educational strategies to ensure their implementation should be developed.

DESI-MS as a tool for direct lipid analysis in cultured cells.

Desorption electrospray ionization may be used as a fast and convenient method for analysis and identification of lipids in the cell culture. Oxidative stress, which usually involves changes in lipids, was used as a model of pathology to show the utility of this analysis methodology. This paper addresses the surface preparation of cell culture slides, induction of oxidative stress, and cell monolayer culture preparation as well as optimization of the analysis. Advantages and drawbacks of the method were also discussed.