The role that biomaterials play in the clinical treatment of damaged organs and tissues is changing. While biomaterials used in permanent medical devices were required to passively take over the function of a damaged tissue in the long term, current biomaterials are expected to trigger and harness the self-regenerative potential of the body in situ and then to degrade, the foundation of regenerative medicine. To meet these different requirements, it is imperative to fully understand the interactions biomaterials have with biological systems, in space and in time. This knowledge will lead to a better understanding of the regenerative capabilities of biomaterials aiding their design with improved functionalities (e.g. biocompatibility, bioactivity). Proteins play a pivotal role in the interaction between biomaterials and cells or tissues. Protein adsorption on the material surface is the very first event of this interaction, which is determinant for the subsequent processes of cell growth, differentiation, and extracellular matrix formation. Against this background, the aim of the current review is to provide insight in the current knowledge of the role of proteins in cell-biomaterial and tissue-biomaterial interactions. In particular, the focus is on proteomics studies, mainly using mass spectrometry, and the knowledge they have generated on protein adsorption of biomaterials, protein production by cells cultured on materials, safety and efficacy of new materials based on nanoparticles and the analysis of extracellular matrices and extracellular matrix-derived products. In the outlook, the potential and limitations of this approach are discussed and mass spectrometry imaging is presented as a powerful technique that complements existing mass spectrometry techniques by providing spatial molecular information about the material-biological system interactions.
These results show that both TNFalpha and IL-1beta regulate mitochondrial function in human articular chondrocytes. Furthermore, the inhibition of complex I by both cytokines could play a key role in cartilage degradation induced by TNFalpha and IL-1beta. These data could be important for understanding of the OA pathogenesis.
Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has established itself among the plethora of mass spectrometry applications. In the biomedical field, MALDI-MSI is being more frequently recognized as a new method for the discovery of biomarkers and targets of treatment, classification of diseased and healthy tissues, or prediction of the outcome of a pathology. The technology has been used to study the localization of proteolytic peptides directly on tissue sections. A direct correlation between the detected peptides and the distribution and identity of the original precursor protein is the ultimate goal of any MALDI-MSI experiment. Enzymatic digestion protocols are commonly used to reveal the protein signature of these complex tissues. Considerations that pertain to methods of sample preparation, on-tissue digestion, data analysis, and visualization will be addressed. This review will also discuss selected applications of on-tissue digestion combined with the MALDI-MSI technology in biomedicine.
Osteoarthritis (OA), characterized by degeneration of the cartilaginous tissue in articular joints, severely impairs mobility in many people worldwide. The degeneration is thought to be mediated by inflammatory processes occurring in the tissue of the joint, including the cartilage. Intra-articular administered triamcinolone acetonide (TAA) is one of the drug treatments employed to ameliorate the inflammation and pain that characterizes OA. However, the penetration and distribution of TAA into the avascular cartilage is not well understood. We employed matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), which has been previously used to directly monitor the distribution of drugs in biological tissues, to evaluate the distribution of TAA in human cartilage after in vitro incubation. Unfortunately, TAA is not easily ionized by regular electrospray ionization (ESI) or MALDI. To overcome this problem, we developed an on-tissue derivatization method with Girard's reagent T (GirT) in human incubated cartilage being able to study its distribution and quantify the drug abundance (up to 3.3 ng/μL). Our results demonstrate the depth of penetration of a corticosteroid drug in human OA cartilage using MALDI-MSI.
Visualizing the distributions
of drugs and their metabolites is
one of the key emerging application areas of matrix-assisted laser
desorption/ionization–mass spectrometry imaging (MALDI-MSI)
within pharmaceutical research. The success of a given MALDI-MSI experiment
is ultimately determined by the ionization efficiency of the compounds
of interest, which in many cases are too low to enable detection at
relevant concentrations. In this work we have taken steps to address
this challenge via the first application of laser-postionisation coupled
with MALDI (so-called MALDI-2) to the analysis and imaging of pharmaceutical
compounds. We demonstrate that MALDI-2 increased the signal intensities
for 7 out of the 10 drug compounds analyzed by up to 2 orders of magnitude
compared to conventional MALDI analysis. This gain in sensitivity
enabled the distributions of drug compounds in both human cartilage
and dog liver tissue to be visualized using MALDI-2, whereas little-to-no
signal from tissue was obtained using conventional MALDI. This work
demonstrates the vast potential of MALDI-2-MSI in pharmaceutical research
and drug development and provides a valuable tool to broaden the application
areas of MSI. Finally, in an effort to understand the ionization mechanism,
we provide the first evidence that the preferential formation of [M
+ H]
+
ions with MALDI-2 has no obvious correlation with
the gas-phase proton affinity values of the analyte molecules, suggesting,
as with MALDI, the occurrence of complex and yet to be elucidated
ionization phenomena.
Objective. Mitochondrial alterations play a key role in the pathogenesis of osteoarthritis (OA). This study evaluated a potential role of mitochondrial respiratory chain (MRC) dysfunction in the inflammatory response of normal human chondrocytes.Methods. Commonly used inhibitors of the MRC were utilized to induce mitochondrial dysfunction in normal human chondrocytes. Levels of prostaglandin E 2 (PGE 2 ) protein and expression of cyclooxygenase 2 (COX-2) and COX-1 messenger RNA (mRNA) and protein were analyzed. To identify the underlying mechanisms responsible for PGE 2 liberation, reactive oxygen species (ROS) were measured. Inhibitors of ROS, including vitamin E, and inhibitors of mitochondrial Ca 2؉ and NF-B were used to test their effects on the MRC.Results. Antimycin A and oligomycin (inhibitors of mitochondrial complexes III and V, respectively) significantly increased the levels of PGE 2 (mean ؎ SEM 505 ؎ 132 pg/50,000 cells and 288 ؎ 104 pg/50,000 cells, respectively, at 24 hours versus a basal level of 29 ؎ 9 pg/50,000 cells; P < 0.05) and increased the expression of COX-2 at both the mRNA and protein levels. Expression of COX-1 did not show any modulation with either inhibitor. Further experiments revealed that antimycin A and oligomycin induced a marked increase in the levels of ROS.
ABSTRACT. Osteoarthritis (OA) is a pathology that ultimately causes joint destruction.The cartilage is one of the principal affected tissues. Alterations in the lipid mediators and an imbalance in the metabolism of cells that form the cartilage (chondrocytes), have been described as contributors to the OA development. In this study, we have studied the distribution of lipids and chemical elements in healthy and OA human cartilage. Time of flight secondary ion mass spectrometry (TOF-SIMS) allows us to study the spatial distribution of molecules at a high resolution on a tissue section. TOF-SIMS revealed a specific peak profile that distinguishes healthy from OA cartilages. The spatial distribution of cholesterol-related peaks exhibited a remarkable difference between healthy and OA cartilages. A distinctive co-localization of cholesterol and other lipids in the superficial area of the cartilage was found. A higher intensity of oleic acid and other fatty acids in the OA cartilages exhibited a similar localization. On the other hand, CNwas observed with a higher intensity in the healthy samples. Finally, we observed an accumulation of calcium and phosphate ions exclusively in areas surrounding the chondrocyte in OA tissues. To our knowledge, this is the first time that TOF-SIMS revealed combined changes in the molecular distribution in the OA human cartilage.
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