Metabolic mapping by use of high-resolution magic angle spinning1H MR spectroscopy for assessment of apoptosis in cervical carcinomas

Background High-resolution magic angle proton magnetic resonance spectroscopy (HR1H MAS MRS) provides a broad metabolic mapping of intact tumor samples and allows for microscopy investigations of the samples after spectra acquisition. Experimental studies have suggested that the method can be used for detection of apoptosis, but this has not been investigated in a clinical setting so far. We have explored this hypothesis in cervical cancers by searching for metabolites associated with apoptosis that were not influenced by other histopathological parameters like tumor load and tumor cell density. Methods Biopsies (n = 44) taken before and during radiotherapy in 23 patients were subjected to HR MAS MRS. A standard pulse-acquire spectrum provided information about lipids, and a spin-echo spectrum enabled detection of non-lipid metabolites in the lipid region of the spectra. Apoptotic cell density, tumor cell fraction, and tumor cell density were determined by histopathological analysis after spectra acquisition. Results The apoptotic cell density correlated with the standard pulse-acquire spectra (p < 0.001), but not with the spin-echo spectra, showing that the lipid metabolites were most important. The combined information of all lipids contributed to the correlation, with a major contribution from the ratio of fatty acid -CH2 to CH3 (p = 0.02). In contrast, the spin-echo spectra contained the main information on tumor cell fraction and tumor cell density (p < 0.001), for which cholines, creatine, taurine, glucose, and lactate were most important. Significant correlations were found between tumor cell fraction and glucose concentration (p = 0.001) and between tumor cell density and glycerophosphocholine (GPC) concentration (p = 0.024) and ratio of GPC to choline (p < 0.001). Conclusion Our findings indicate that the apoptotic activity of cervical cancers can be assessed from the lipid metabolites in HR MAS MR spectra and that the HR MAS data may reveal novel information on the metabolic changes characteristic of apoptosis. These changes differed from those associated with tumor load and tumor cell density, suggesting an application of the method to explore the role of apoptosis in the course of the disease

Principal component analysis for the comparison of metabolic profiles from human rectal cancer biopsies and colorectal xenografts using high-resolution magic angle spinning 1H magnetic resonance spectroscopy

<p>Abstract</p> <p>Background</p> <p>This study was conducted in order to elucidate metabolic differences between human rectal cancer biopsies and colorectal HT29, HCT116 and SW620 xenografts by using high-resolution magnetic angle spinning (MAS) magnetic resonance spectroscopy (MRS) and for determination of the most appropriate human rectal xenograft model for preclinical MR spectroscopy studies. A further aim was to investigate metabolic changes following irradiation of HT29 xenografts.</p> <p>Methods</p> <p>HR MAS MRS of tissue samples from xenografts and rectal biopsies were obtained with a Bruker Avance DRX600 spectrometer and analyzed using principal component analysis (PCA) and partial least square (PLS) regression analysis.</p> <p>Results and conclusion</p> <p>HR MAS MRS enabled assignment of 27 metabolites. Score plots from PCA of spin-echo and single-pulse spectra revealed separate clusters of the different xenografts and rectal biopsies, reflecting underlying differences in metabolite composition. The loading profile indicated that clustering was mainly based on differences in relative amounts of lipids, lactate and choline-containing compounds, with HT29 exhibiting the metabolic profile most similar to human rectal cancers tissue. Due to high necrotic fractions in the HT29 xenografts, radiation-induced changes were not detected when comparing spectra from untreated and irradiated HT29 xenografts. However, PLS calibration relating spectral data to the necrotic fraction revealed a significant correlation, indicating that necrotic fraction can be assessed from the MR spectra.</p

Merging transcriptomics and metabolomics - advances in breast cancer profiling

Background Combining gene expression microarrays and high resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS) of the same tissue samples enables comparison of the transcriptional and metabolic profiles of breast cancer. The aim of this study was to explore the potential of combining these two different types of information. Methods Breast cancer tissue from 46 patients was analyzed by HR MAS MRS followed by gene expression microarrays. Two strategies were used to combine the gene expression and metabolic data; first using multivariate analyses to identify different groups based on gene expression and metabolic data; second correlating levels of specific metabolites to transcripts to suggest new hypotheses of connections between metabolite levels and the underlying biological processes. A parallel study was designed to address experimental issues of combining microarrays and HR MAS MRS. Results In the first strategy, using the microarray data and previously reported molecular classification methods, the majority of samples were classified as luminal A. Three subgroups of luminal A tumors were identified based on hierarchical clustering of the HR MAS MR spectra. The samples in one of the subgroups, designated A2, showed significantly lower glucose and higher alanine levels than the other luminal A samples, suggesting a higher glycolytic activity in these tumors. This group was also enriched for genes annotated with Gene Ontology (GO) terms related to cell cycle and DNA repair. In the second strategy, the correlations between concentrations of myo-inositol, glycine, taurine, glycerophosphocholine, phosphocholine, choline and creatine and all transcripts in the filtered microarray data were investigated. GO-terms related to the extracellular matrix were enriched among the genes that correlated the most to myo-inositol and taurine, while cell cycle related GO-terms were enriched for the genes that correlated the most to choline. Additionally, a subset of transcripts was identified to have slightly altered expression after HR MAS MRS and was therefore removed from all other analyses. Conclusions Combining transcriptional and metabolic data from the same breast carcinoma sample is feasible and may contribute to a more refined subclassification of breast cancers as well as reveal relations between metabolic and transcriptional levels. See Commentary: http://www.biomedcentral.com/1741-7015/8/7

Distinct choline metabolic profiles are associated with differences in gene expression for basal-like and luminal-like breast cancer xenograft models

<p>Abstract</p> <p>Background</p> <p>Increased concentrations of choline-containing compounds are frequently observed in breast carcinomas, and may serve as biomarkers for both diagnostic and treatment monitoring purposes. However, underlying mechanisms for the abnormal choline metabolism are poorly understood.</p> <p>Methods</p> <p>The concentrations of choline-derived metabolites were determined in xenografted primary human breast carcinomas, representing basal-like and luminal-like subtypes. Quantification of metabolites in fresh frozen tissue was performed using high-resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS).</p> <p>The expression of genes involved in phosphatidylcholine (PtdCho) metabolism was retrieved from whole genome expression microarray analyses.</p> <p>The metabolite profiles from xenografts were compared with profiles from human breast cancer, sampled from patients with estrogen/progesterone receptor positive (ER+/PgR+) or triple negative (ER-/PgR-/HER2-) breast cancer.</p> <p>Results</p> <p>In basal-like xenografts, glycerophosphocholine (GPC) concentrations were higher than phosphocholine (PCho) concentrations, whereas this pattern was reversed in luminal-like xenografts. These differences may be explained by lower choline kinase (<it>CHKA</it>, <it>CHKB</it>) expression as well as higher PtdCho degradation mediated by higher expression of phospholipase A2 group 4A (<it>PLA2G4A</it>) and phospholipase B1 (<it>PLB1</it>) in the basal-like model. The glycine concentration was higher in the basal-like model. Although glycine could be derived from energy metabolism pathways, the gene expression data suggested a metabolic shift from PtdCho synthesis to glycine formation in basal-like xenografts. In agreement with results from the xenograft models, tissue samples from triple negative breast carcinomas had higher GPC/PCho ratio than samples from ER+/PgR+ carcinomas, suggesting that the choline metabolism in the experimental models is representative for luminal-like and basal-like human breast cancer.</p> <p>Conclusions</p> <p>The differences in choline metabolite concentrations corresponded well with differences in gene expression, demonstrating distinct metabolic profiles in the xenograft models representing basal-like and luminal-like breast cancer. The same characteristics of choline metabolite profiles were also observed in patient material from ER+/PgR+ and triple-negative breast cancer, suggesting that the xenografts are relevant model systems for studies of choline metabolism in luminal-like and basal-like breast cancer.</p

Prognostic value of metabolic response in breast cancer patients receiving neoadjuvant chemotherapy

<p>Abstract</p> <p>Background</p> <p>Today's clinical diagnostic tools are insufficient for giving accurate prognosis to breast cancer patients. The aim of our study was to examine the tumor metabolic changes in patients with locally advanced breast cancer caused by neoadjuvant chemotherapy (NAC), relating these changes to clinical treatment response and long-term survival.</p> <p>Methods</p> <p>Patients (n = 89) participating in a randomized open-label multicenter study were allocated to receive either NAC as epirubicin or paclitaxel monotherapy. Biopsies were excised pre- and post-treatment, and analyzed by high resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS). The metabolite profiles were examined by paired and unpaired multivariate methods and findings of important metabolites were confirmed by spectral integration of the metabolite peaks.</p> <p>Results</p> <p>All patients had a significant metabolic response to NAC, and pre- and post-treatment spectra could be discriminated with 87.9%/68.9% classification accuracy by paired/unpaired partial least squares discriminant analysis (PLS-DA) (<it>p </it>< 0.001). Similar metabolic responses were observed for the two chemotherapeutic agents. The metabolic responses were related to patient outcome. Non-survivors (< 5 years) had increased tumor levels of lactate (<it>p </it>= 0.004) after treatment, while survivors (≥ 5 years) experienced a decrease in the levels of glycine (<it>p </it>= 0.047) and choline-containing compounds (<it>p </it>≤ 0.013) and an increase in glucose (<it>p </it>= 0.002) levels. The metabolic responses were not related to clinical treatment response.</p> <p>Conclusions</p> <p>The differences in tumor metabolic response to NAC were associated with breast cancer survival, but not to clinical response. Monitoring metabolic responses to NAC by HR MAS MRS may provide information about tumor biology related to individual prognosis.</p

Urinary detection of corticosteroid in topical treatment of skin disease by 19F MRS

Objective To investigate if it was feasible to quantify the renal excretion of topically applied corticosteroids by 19F MRS. Materials and methods Five participants, one healthy and four with skin diseases, were treated with ointment containing betamethasone 17-valerate. Urine samples were collected for up to 87 h after the initial application. A sample of ointment mixed with urine served as a study control. Organic fractions were obtained after sample freeze drying, and resolved in deuterated chloroform prior to acquisition of 19F MR spectra at 470 MHz for typically 8 h. Results We detected fuorine signals in 40 of the 62 fractions of organic extracts. The corticosteroid was etected in samples from all patients, ranging from 0.1 to 2.8% of the applied steroid. No fuorine signal was obtained in samples from the healthy volunteer. Discussion 19F MRS can be utilized to detect topically applied corticosteroids in urine. However, more work is required to optimize and control for extraction procedures, complete spectral assignments and reliable quantifcation

Tissue characterization by high resolution magic angle spinning MR spectroscopy

Vevs-karakterisering med høyoppløsning MAS MR spektroskopi Høyoppløsning MAS er en MR spektroskopisk metode som gir høyt oppløste spekter av faste materialer. I dette doktorgradsarbeidet har høyoppløsning MAS blitt anvendt på forskjellige typer humant vev. Det primære målet var å etablere en metode for å studere biokjemiske egenskaper i vevsprøver, med hovedvekt på vev fra brystkreftpasienter. Prøvepreparering før MAS analyser er enkelt sammenlignet med ekstraksjon. Vi har funnet at oppløsningen i spektrene, og dermed den oppnåelige biokjemiske informasjonen, er tilsvarende som i spekter fra ekstrakter av vevsprøver. En viktig fordel i forhold til ekstraksjons-metoder er at vevsprøven som studeres kan bevares slik at den kan vurderes ved andre metoder etterpå. Organer er gjerne satt sammen av forskjellige typer celler og vev og en slik heterogenitet vil ha betydning for den biokjemiske profilen, siden celler av forskjellig type kan ha forskjellig metabolisme. En del av prosjektet gikk ut på å optimalisere MR eksperimentene med hensyn på biokjemisk informasjon samtidig som at vevsprøven ble bevart for en patologisk undersøkelse. Lav temperatur under analysene ble funnet å være viktig for en slik bevaring av vevet. Vi oppnådde høyt oppløste spekter og har langt på vei kartlagt den kjemiske sammensetningen av intakte vevsprøver. Den metabolske profilen i brystkreftprøver viste en sammenheng med vevs-sammensetning bestemt ved patologi. MR spekter av biologisk materiale kan inneholde hundrevis av topper, og flere av disse kan henge sammen med sykdomsprosesser i vevet. Ved sammenligning av enkelt-topper mot kliniske funn kan man miste viktig informasjon i spektrene som er ikke er synlig for det blotte øyet. Multivariate analyser gjør det mulig å undersøke hele spektrene mot kliniske kjennetegn. I denne avhandlingen har prisipalkomponent-analyse blitt brukt til å korrelere MAS spektrene med pasientenes diagnoser og andre kliniske funn. En studie av livmorhalskreft omfattet vevsprøver fra åtte pasienter med livmorhalskreft og åtte kontroller. Prinsipalkomponent-analyse av MAS spektrene ga to klare grupperinger av de ulike spektrene i samsvar med prøvetype. Den kjemiske profilen bestemt med MAS har en sammenheng med de makroskopiske forandringene i kreftvev fra livmorhals. Hjerneautopsier fra pasienter med en sjelden neurodegenerativ sykdom som rammer barn (neuronal ceroid lipofuscinosis) ble undersøk på samme måte mot autopsier fra personer uten kjent sykdom i nervesystemet. To former av sykdommen var inkludert i studien som omfattet totalt 24 biopsier, og den formen som bryter ut tidligst lot seg skille fra de to andre gruppene. Vevsprøver fra denne gruppen inneholdt svært lite eller ikke påviselige mengder NAA, som syntetiseres og lagres i nevroner. Dette korrelerer med tap av nevroner som er observert hos slike pasienter. Den største studien inkluderte vevsprøver fra svulst og ikke-infiltrert vev (n=18) fra 85 brystkreftpasienter. MAS spekter fra disse prøvene ble undersøkt med hensyn på absolutt konsentrasjon av bestemte metabolitter og ved PCA med hensyn på sammenheng med flere kliniske parametere, som pasientens diagnose, svulstens størrelse og lymfeknutestatus hos pasienten. Det ble funnet flere trender til sammenhenger mellom MAS spekter og kliniske parametere. Det mest lovende resultatet med hensyn på fremtidig klinisk verdi var en mulig korrelasjon med lymfeknutestatus hos pasientgruppen med den vanligste formene for brystkreft.Paper III is a preprint of an article published in NMR in Biomedicine. http://www.interscience.wiley.co

Utvikling av nettbasert studietilbud ved NTNU – tverrprofesjonelt samarbeid er suksesskriteriet

Den teknologiske utviklingen og en økende digitalisering i samfunnet har åpnet for samhandling på tvers av geografi og institusjonelle grenser. Utviklingen har medført et endret arbeidsliv og dermed også en endret studentmasse. For svært mange yrkesgrupper vil kontinuerlig læring og kompetanseheving bli stadig viktigere, fordi arbeidsoppgaver er i stadig endring. Styrking av kompetansen innen forskning, innovasjon og kunnskapsbasert praksis i de kommunale helse- og omsorgstjenestene er et viktig mål i Kompetanseløft 2020 (Helsedirektoratet, 2017). Systematisk kompetanseheving er også nedfelt i viktige tiltak for å møte fremtidens utfordringer i helsevesenet (Helse- og omsorgsdepartementet, 2014). For personer som er i arbeid vil studier som lar seg kombinere med jobb være det mest aktuelle og mulige studietilbudet å kunne gjennomføre. Kvalitetsmeldingen (Kunnskapsdepartementet, 2017a) understreker betydningen av at digitale muligheter utnyttes for at alle studenter skal møte aktiviserende og varierte lærings- og vurderingsformer. I tillegg til faglig relevant digital kompetanse skal studenten tilegne seg mer overordnet IKT-kompetanse og digital dømmekraft, som er relevant på tvers av fagområdene (Kunnskapsdepartementet, 2017b). Universitets- og høgskolesektoren skal tilby utdanninger for å møte dette endrede samfunnsbehovet

Er forelesninga effektiv, interessant og meningsfull? - Oppfatninger om og betydningen av forelesninger som undervisningsform

Radiografstudiet er en kombinasjon av teoretisk undervisning og ferdighetstrening ved utdanningsinstitusjon og praksisstudier ved forskjellige bildediagnostiske og kliniske enheter. Radiografutdanningen ved Høgskolen i Sør-Trøndelag (HiST) benytter ulike pedagogiske verktøy for å imøtekomme Kvalitetsreformens krav om tettere oppfølging og utnytting av ny teknologi i undervisningen. Tilbudet av andre ressurser enn forelesning for læring er stort og økende, delvis gjennom anbefalt og ønsket bruk av ny teknologi ved utdanningsinstitusjonene. Samtidig er forelesningen beholdt som sentral undervisningsform. Vedvarende lavt oppmøte til forelesninger er bakgrunnen for denne evalueringen av forelesning som undervisningsform, gjennom dens betydning for læring og relevans for studentenes læringsstrategier. Tilstedeværelse for i alt 106 studenter, i ti emner fordelt på tre studieår, ble registrert for studieåret 2013/2014 og koblet til karakterdata. Nyttelsesgrad av tilrettelagte nettressurser ble kartlagt i de utvalgte emnene. Det ble gjennomført dybdeintervju med sju studenter om forelesningsoppmøte og hvordan forelesningen og andre ressurser inngår i egen læring. Resultatene bekrefter sammenheng mellom eksamenskarakter og oppmøte. Videre viste nyttelsesgrad av tilrettelagte nettressurser og studenters beskrivelse av egen læringsstrategi stor grad av instrumentell tilnærming for læring av teori. Intervju med studenter viste tydelig at de ønsker forelesninger, og at kunnskap tilegnet i forelesninger er grunnleggende for dybdelæring i praksisstudier