Thermal liquid biopsy for monitoring melanoma patients under surveillance during treatment: A pilot study

Background

Differential Scanning Calorimetry (DSC) is a technique traditionally used to study thermally induced macromolecular transitions, and it has recently been proposed as a novel approach for diagnosis and monitoring of several diseases. We report a pilot study applying Thermal Liquid Biopsy (TLB, DSC thermograms of plasma samples) as a new clinical approach for diagnostic assessment of melanoma patients.

Statistical analysis of plasma thermograms measured by differential scanning calorimetry

Melting curves of human plasma measured by differential scanning calorimetry (DSC), known as thermograms, have the potential to markedly impact diagnosis of human diseases. A general statistical methodology is developed to analyze and classify DSC thermograms to analyze and classify thermograms. Analysis of an acquired thermogram involves comparison with a database of empirical reference thermograms from clinically characterized diseases. Two parameters, a distance metric, P, and correlation coefficient, r, are combined to produce a 'similarity metric,' ρ, which can be used to classify unknown thermograms into pre-characterized categories. Simulated thermograms known to lie within or fall outside of the 90% quantile range around a median reference are also analyzed. Results verify the utility of the methods and establish the apparent dynamic range of the metric ρ. Methods are then applied to data obtained from a collection of plasma samples from patients clinically diagnosed with SLE (lupus). High correspondence is found between curve shapes and values of the metric ρ. In a final application, an elementary classification rule is implemented to successfully analyze and classify unlabeled thermograms. These methods constitute a set of powerful yet easy to implement tools for quantitative classification, analysis and interpretation of DSC plasma melting curves.     

Calorimetry outside the box: a new window into the plasma proteome

Differential scanning calorimetry provides a new window into the plasma proteome. Plasma from normal individuals yields a characteristic, reproducible thermogram that appears to represent the weighted sum of denaturation profiles of the most abundant constituent plasma proteins. Plasma from diseased individuals yields dramatically different signature thermograms. Thermograms from individuals suffering from rheumatoid arthritis, systemic lupus, and Lyme disease were measured. Each disease appears to have a distinctive and characteristic thermogram. The difference in thermograms between normal and diseased individuals is not caused by radical changes in the concentrations of the most abundant plasma proteins but rather appears to result from interaction of as yet unknown biomarkers with the major plasma proteins. These results signal a novel use for calorimetry as a diagnostic tool.     

Characterization of Monoclonal Gammopathy of Undetermined Significance by Calorimetric Analysis of Blood Serum Proteome

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant proliferative disorder that may progress to multiple myeloma, a malignant plasma cell neoplasia. We evaluated differential scanning calorimetry (DSC) as an experimental tool for differentiating serum samples of MGUS patients from healthy individuals. DSC thermograms can be used for monitoring changes in the serum proteome associated with MGUS. MGUS patients showed great variability in serum thermogram characteristics, which depended on the IgG, IgA or IgM isotypes and/or the κ or λ light chains. Thermogram feature parameters distinguished patients with MGUS from healthy people. Serum samples, named as non-MGUS, were also collected from patients with subjacent immunological pathologies who were discarded of having MGUS through serum immunofixation. They were used to verify the sensitivity of DSC for discriminating MGUS from related blood dyscrasias. Only some DSC thermogram feature parameters differentiated, to a lesser extent, between MGUS and non-MGUS individuals. We contemplate DSC as a tool for early diagnosis and monitoring of MGUS.     

In vivo characterization of thermal stabilities of Aeropyrum pernix cellular components by differential scanning calorimetry

Revival studies of Aeropyrum pernix show that the viability of cells and cell recovery after heat treatment depends on the temperature of treatment. Differential scanning calorimetry (DSC) is used to analyze the relative thermal stabilities of cellular components of A. pernix and to identify the cellular components responsible for the observed lag phase and reduced maximum growth following a heat treatment. DSC thermograms show 5 visible endothermic transitions with 2 major transitions. DSC analysis of isolated crude ribosomes aids the assignment of the 2 major peaks observed in whole-cell thermograms to denaturation of ribosomal structures. A comparison of partial and immediate full rescan thermograms of A. pernix whole cells indicates that both major peaks represent irreversible thermal transitions. A DNA peak is also identified in the whole-cell thermogram by comparison with the optical data of isolated pure DNA. DNA melting is shown to be irreversible in dilute solution, whereas it is partially reversible in whole cells, owing at least in part, to restricted volume effects. In contrast to mesophilic organisms, hyperthermophilic A. pernix ribosomes are more thermally stable than DNA, but in both organisms, irreversible changes leading to cell death occur owing to ribosomal denaturation.     

Update on: proteome analysis in thyroid pathology – part II: overview of technical and clinical enhancement of proteomic investigation of the thyroid lesions

ABSTRACT

Introduction: An accurate diagnostic classification of thyroid lesions remains an important clinical aspect that needs to be addressed in order to avoid ‘diagnostic’ thyroidectomies. Among the several ‘omics’ techniques, proteomics is playing a pivotal role in the search for diagnostic markers. In recent years, different approaches have been used, taking advantage of the technical improvements related to mass spectrometry that have occurred.

Areas covered: The review provides an update of the recent findings in diagnostic classification, in genetic definition and in the investigation of thyroid lesions based on different proteomics approaches and on different type of specimens: cytological, surgical and biofluid samples. A brief section will discuss how these findings can be integrated with those obtained by metabolomics investigations.

Expert commentary: Among the several proteomics approaches able to deepen our knowledge of the molecular alterations of the different thyroid lesions, MALDI-MSI is strongly emerging above all. In fact, MS-imaging has also been demonstrated to be capable of distinguishing thyroid lesions, based on their different molecular signatures, using cytological specimens. The possibility to use the material obtained by the fine needle aspiration makes MALDI-MSI a highly promising technology that could be implemented into the clinical and pathological units.     

Calorimetric analysis of the plasma proteome: Identification of type 1 diabetes patients with early renal function decline

Background

Microalbuminuria (MA) has been questioned as a predictor of progressive renal dysfunction in patients with type 1 diabetes (T1D). Consequently, new clinical end points are needed that identify or predict patients that are at risk for early renal function decline (ERFD). The potential clinical utility of differential scanning calorimetry (DSC) analysis of blood plasma and other biofluids has recently been reported. This method provides an alternate physical basis with which to study disease-associated changes in the bulk plasma proteome.

Methods

DSC analysis of blood plasma was applied to identify unique signatures of ERFD in subjects enrolled in the 1st Joslin Study of the Natural History of Microalbuminuria in Type 1 Diabetes, a prospective cohort study of T1D patients. Recent data suggests that differences in the plasma peptidome of these patients correlate with longitudinal measures of renal function. Differences in DSC profile (thermogram) features were evaluated between T1D MA individuals exhibiting ERFD (n = 15) and matched control subjects (n = 14).

Results

The average control group thermogram resembled a previously defined healthy thermogram. Differences were evident between ERFD and control individuals. Heat capacity values of the main two transitions were found to be significant discriminators of patient status.

Conclusions

Results from this pilot study suggest the potential utility of DSC proteome analysis to prognostic indicators of renal disease in T1D.

General significance

DSC shows sensitivity to changes in the bulk plasma proteome that correlate with clinical status in T1D providing additional support for the utility of DSC profiling in clinical diagnostics.     

Syndromic Approach to Arboviral Diagnostics for Global Travelers as a Basis for Infectious Disease Surveillance

BackgroundArboviruses have overlapping geographical distributions and can cause symptoms that coincide with more common infections. Therefore, arbovirus infections are often neglected by travel diagnostics. Here, we assessed the potential of syndrome-based approaches for diagnosis and surveillance of neglected arboviral diseases in returning travelers.MethodTo map the patients high at risk of missed clinical arboviral infections we compared the quantity of all arboviral diagnostic requests by physicians in the Netherlands, from 2009 through 2013, with a literature-based assessment of the travelers’ likely exposure to an arbovirus.Results2153 patients, with travel and clinical history were evaluated. The diagnostic assay for dengue virus (DENV) was the most commonly requested (86%). Of travelers returning from Southeast Asia with symptoms compatible with chikungunya virus (CHIKV), only 55% were tested. For travelers in Europe, arbovirus diagnostics were rarely requested. Over all, diagnostics for most arboviruses were requested only on severe clinical presentation.ConclusionTravel destination and syndrome were used inconsistently for triage of diagnostics, likely resulting in vast under-diagnosis of arboviral infections of public health significance. This study shows the need for more awareness among physicians and standardization of syndromic diagnostic algorithms.     

Structural Contribution of the Carbohydrate Moiety to the Alkaline Hydrolysis of Aryl Glycosylamine Linkages

Differential scanning calorimetry (DSC) thermograms of soybean protein isolate developed two peaks corresponded to 11S and 7S globulin, the denaturation temperatures of which were 93.3 and 76.5°C, respectively, with 94% water. These peaks shifted to higher temperatures with lower water contents of the sample. At 47% water, there were two peaks, at 149 and 118.7°C, and at 11% water, there was one peak at 180°C. The DSC thermogram measured during cooling and reheating gave no peak. The soybean protein isolate was heated with 24.5% water at 100°C and then mixed with more water to the water contents of 94%. This sample gave two peaks at temperatures close to those of the original soybean protein, indicating that the soybean protein was not denatured at temperatures even above 100°C when the water content was low.     

The thermotropic behavior and fatty radical composition of major phospholipids of the tanner crab <Emphasis Type="Italic">Chionoecetes bairdi</Emphasis> Rathbun, 1924

This study examines the fatty radical (FR) composition and heat-induced crystalline to liquidcrystalline phase transitions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from the gills, hepatopancreas, gonads, and muscle of the tanner crab Chionoecetes bairdi, which was collected in the summer at a near-bottom water temperature of 2.8°C. The location of the PC and PE thermograms below 2.8°C indicates the functionally optimal liquid crystalline state of the membrane lipid matrix. The proximity of the thermogram profiles of PC and PE from the different organs and tissues of C. bairdi and significant overlapping of the temperature areas of transitions (symbatic behavior) correlate with a similar composition of major FR and their total parameters in PC and PE. The obtained data point to the effective adaptation of the bairdi crab to low water temperatures and to the need for adaptive changes in the FR composition or change of habitat with increasing temperature. The thermotropic behavior of muscle PC, in which the greater part of the thermogram is in the temperature range from 2.8 to 32°C, suggests a potential for the tanner crab to adapt to increased temperatures.     

Detection of Cervical Cancer Biomarker Patterns in Blood Plasma and Urine by Differential Scanning Calorimetry and Mass Spectrometry

Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN) and extent of spread of invasive carcinomas of the cervix (IC) are needed. Differential scanning calorimetry (DSC) has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms) were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS) analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate cervical cancer health.     

Efficient Derivation of Multipotent Neural Stem/Progenitor Cells from Non-Human Primate Embryonic Stem Cells

The common marmoset (Callithrix jacchus) is a small New World primate that has been used as a non-human primate model for various biomedical studies. We previously demonstrated that transplantation of neural stem/progenitor cells (NS/PCs) derived from mouse and human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) promote functional locomotor recovery of mouse spinal cord injury models. However, for the clinical application of such a therapeutic approach, we need to evaluate the efficacy and safety of pluripotent stem cell-derived NS/PCs not only by xenotransplantation, but also allotransplantation using non-human primate models to assess immunological rejection and tumorigenicity. In the present study, we established a culture method to efficiently derive NS/PCs as neurospheres from common marmoset ESCs. Marmoset ESC-derived neurospheres could be passaged repeatedly and showed sequential generation of neurons and astrocytes, similar to that of mouse ESC-derived NS/PCs, and gave rise to functional neurons as indicated by calcium imaging. Although marmoset ESC-derived NS/PCs could not differentiate into oligodendrocytes under default culture conditions, these cells could abundantly generate oligodendrocytes by incorporating additional signals that recapitulate in vivo neural development. Moreover, principal component analysis of microarray data demonstrated that marmoset ESC-derived NS/PCs acquired similar gene expression profiles to those of fetal brain-derived NS/PCs by repeated passaging. Therefore, marmoset ESC-derived NS/PCs may be useful not only for accurate evaluation by allotransplantation of NS/PCs into non-human primate models, but are also applicable to analysis of iPSCs established from transgenic disease model marmosets.     

Mg2+ Dependence of the Structure and Thermodynamics of Wheat Germ and Lupin Seeds 5S rRNA

Abstract

The formation and stability of structural elements in two 5S rRNA molecules from wheat germ (WG) and lupin seeds (LS) as a function of Mg²⁺ concentration in solution was determined using the adiabatic differential scanning microcalorimetry (DSC). The experimentally determined thermodynamic parameters are compared with calculations using thermodynamic databases used for prediction of RNA structure. The 5S rRNA molecules which show minor differences in the nucleotide sequence display very different thermal unfolding profiles (DSC profiles). Numerical deconvolution of DSC profiles provided information about structural transformations that take place in both 5S rRNA molecules. A comparative analysis of DSC data and the theoretical thermodynamic models of the structure was used to establish a relationship between the constituting transitions found in the melting profiles and the unfolding of structural domains of the 5S rRNA and stability of its particular helical elements.

Increased concentration of Mg²⁺ ions induces additional internal interactions stabilising 5S rRNA structures found at low Na⁺ concentrations. Observed conformational transitions suggest a structural model in which the extension of helical region E dominates over the postulated tertiary interaction between hairpin loops. We propose that helix E is stabilised by a sequence of non-standard pairings extending this helix by the formation of tetra loop e and an almost total reduction of loop d between helices E and D. Two hairpin structures in both 5S rRNA molecules: the extended C-C' and the extended E-E'-E” hairpins appear as the most stable elements of the structure. The cooperativity of the unfolding of helixes in these 5S rRNA molecules changes already at 2 mM Mg²⁺.     

Phase transitions of phospholipids as a criterion for assessing the capacity for thermal adaptation in fish

This study examines the crystal-liquid crystal phase transitions of the major phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), from muscle tissue of marine fish living at temperatures of 0–4.1°C (the Pacific cod Gadus macrocephalus, banded Irish lord Hemilepidotus gilberti, Pacific halibut Hippoglossus hippoglossus, black edged sculpin Gymnocanthus herzensteini, dark colored flounder Pleuronectes obscurus, and plain sculpin Myoxocephalus jaok), as well as of fish living at 14 and 18°C (Pacific redfin Tribolodon brandti). The PC and PE phase-transition thermograms of all the investigated species displayed specific profiles. The largest share of the thermogram area at temperatures higher than those of the habitat was found for the PC (28–40%) and PE (47–82%) of the black-edged sculpin, dark-colored flounder, and the plain sculpin, which have reduced physiological activity at low temperatures. In the Pacific cod, banded Irish lord, and the Pacific redfin, this parameter was much lower, 0–18% (PC) and 0–39% (PE). The thermotropic behavior PC and PE was symbate in all fish, except for the cod and the plain sculpin. The transition enthalpy of PC in all the investigated species was 2.8 times higher than that of PE. To interpret the varied PC and PE thermogram profiles of fish with similar fatty-acid compositions, the data on the composition of the molecular species of these phospholipids appeared to be the most informative. This study suggests that each fish species has its own strategy for thermal adaptation, which is realized through a certain set of phospholipid molecular species.     

Heat-triggered conversion of protofibrils into mature amyloid fibrils of beta2-microglobulin

Heat-triggered conversion of the salt-induced thin and flexible protofibrils into well-organized thick and straight mature amyloid fibrils was achieved with beta2-microglobulin, a protein responsible for dialysis-related amyloidosis. First, protofibrils that formed spontaneously at pH 2.5 in the presence of 0.5 M NaCl were aggregated by agitating the solution. Second, the aggregated protofibrils were heated in a cell of a differential scanning calorimeter (DSC). The DSC thermogram showed an exothermic transition with sigmoidal temperature dependence, resulting in a remarkably large decrease in the heat capacity of the solution. Third, on the basis of electron microscopy together with circular dichroism spectroscopy, seeding experiments, and a thioflavin T binding assay, the sigmoidal transition was found to represent the conversion of protofibrils into mature amyloid fibrils. Furthermore, DSC thermograms obtained at various heating rates revealed that the transition curve depends on the heating rate, implying that the effects of heat associated with the conversion to the mature fibrils are kinetically controlled, precluding an interpretation in terms of equilibrium thermodynamics. Taken together, these results highlight the importance of the change in heat capacity in addressing the biological significance of interactions between solvent water and amyloid fibrils and, moreover, in detecting the formation of amyloid fibrils.     

Effect of Milling on DSC Thermogram of Excipient Adipic Acid

The purpose of this research was to investigate why and how mechanical milling results in an unexpected shift in differential scanning calorimetry (DSC) measured fusion enthalpy (∆_fus H) and melting point (T _m) of adipic acid, a pharmaceutical excipient. Hyper differential scanning calorimetry (hyper-DSC) was used to characterize adipic acid before and after ball-milling. An experimental study was conducted to evaluate previous postulations such as electrostatic charging using the Faraday cage method, crystallinity loss using powder X-ray diffraction (PXRD), thermal annealing using DSC, impurities removal using thermal gravimetric analysis (TGA) and Karl Fischer titration. DSC thermograms showed that after milling, the values of ∆_fus H and T _m were increased by approximately 9% and 5 K, respectively. Previous suggestions of increased electrostatic attraction, change in particle size distribution, and thermal annealing during measurements did not explain the differences. Instead, theoretical analysis and experimental findings suggested that the residual solvent (water) plays a key role. Water entrapped as inclusions inside adipic acid during solution crystallization was partially evaporated by localized heating at the cleaved surfaces during milling. The correlation between the removal of water and melting properties measured was shown via drying and crystallization experiments. These findings show that milling can reduce residual solvent content and causes a shift in DSC results.     

Acylation of the S413-PV cell-penetrating peptide as a means of enhancing its capacity to mediate nucleic acid delivery: Relevance of peptide/lipid interactions

BackgroundCell-penetrating peptides (CPPs) have been extensively exploited in gene therapy approaches as vectors for intracellular delivery of bioactive molecules. The ability of CPPs to be internalized into cells and their capacity to complex nucleic acids depend on their molecular structure, both primary and secondary, namely regarding hydrophobicity/hydrophilicity. CPP acylation has been used as a strategy to improve this structural feature.MethodsAcyl groups (from 6 to 18 carbon atoms) were attached to the S4₁₃-PV peptide and their effects on the peptide competence to complex siRNAs and to mediate gene silencing in glioblastoma (GBM) cells were studied. A systematic characterization of membrane interactions with S4₁₃-PV acyl-derivatives was also conducted, using different biophysical techniques (surface pressure-area isotherms in Langmuir monolayers, DSC and ³¹P NMR) to unravel a relationship between CPP biological activity and CPP effects on membrane stability and lipid organization.ResultsA remarkable concordance was noticed between acylated-S4₁₃-PV peptide competence to promote gene silencing in GBM cells and disturbance induced in membrane models, the lauroyl- and myristoyl-S4₁₃-PV peptides being the most effective. A cut-off effect was described for the first time regarding the influence of acyl-chain length on CPP bioactivity.ConclusionsC12-S4₁₃-PV showed high capacity to destabilize lipid bilayers, to escape from lysosomal degradation and to mediate gene silencing without promoting cytotoxicity.General significanceBesides unraveling a new CPP with high potential to be employed as a gene delivery vector, this work emphasizes the benefit from allying biophysical and biological studies towards a proper CPP structural refinement for successful pre-clinical/clinical application.     

Clinical and Radiological Features of Pheochromocytoma/Ganglioneuroma Composite Tumors: A Case Series with Comparative Analysis

ObjectiveTo describe and compare the clinical, biochemical, radiologic, and pathologic features of adrenal pheochromocytoma-ganglioneuroma (PC-GN) composites with the features of isolated pheochromocytomas (PCs) and adrenal ganglioneuromas (AGNs).MethodsWe reviewed data for PC-GN composite cases seen at a single tertiary center between 1993 and 2012 and compared them with cases of isolated AGN and relatively similar median-size PCs.ResultsNine PC-GN composites were included. The median age at diagnosis was 52 years (range, 28 to 83 years) for PC-GN compared with 55 years (range, 24 to 78 years) for PC patients and 40 years (range, 18 to 64 years) for AGN patients. Similar to PCs, all PC-GN composites were associated with catecholamine overproduction, whereas AGNs were nonfunctioning. On pathology, the median tumor sizes were 7 cm (range, 2.5 to 13 cm) for PC-GN tumors, 6.5 cm (range, 3.5 to 7 cm) for PCs, and 8 cm (range, 3.2 to 20 cm) for AGNs. On computed tomography (CT) imaging, PC-GN composites and PCs were heterogeneous, with both having significantly higher postcontrast density values than AGNs, which typically looked homogeneous and had a progressive enhancement pattern without contrast washout in most cases.ConclusionThe presence of a PC component significantly increases tumor heterogeneity and postcontrast density values. CT imaging could be very helpful in distinguishing AGNs from both PC-GN and PC tumors, but only pathologic examination can yield the diagnosis. Clinically and radiologically, PC-GN composites are indistinguishable from PCs and need to be managed similarly. (Endocr Pract. 2014;20:864-869)