Phthalocyanines are promising photosensitizers for photodynamic therapy due to their advantageous light absorption properties and low dark toxicity. Two non-peripheral substituted phthalocyanines, tetra-ethoxy-Zn-phthalocyanine (CH3Pc) and its fluorinated analogue (CF3Pc), were combined with different nanocarriers, and their photophysical properties and biological activities were studied. Carrier-encapsulation and phthalocyanines' aggregation state were probed by NMR-, UV-Vis-, and fluorescence spectroscopy. Five different carrier systems were compared: polyvinylpyrrolidone (PVP), two triblock copolymer micelles (Synperonic P84, "P84", and Pluronic F127, "F127"), self-emulsifying detergent micelles (Kolliphor RH40, "RH40"), and 1, 2-dioleoyl-sn-glycero-3-phosphocholine unilamellar vesicles (ULVs). CH3Pc inserted efficiently into P84, F127 and RH40 micelles in monomeric form, while CF3Pc was encapsulated as dimers and oligomers. ULVs were capable to efficiently monomerize and encapsulate both phthalocyanines. PVP was not suitable to solubilize neither of these phthalocyanines. The localization of CH3Pc and CF3Pc at the carrier interfaces was determined by NMR-experiments with atomic resolution. All phthalocyanine-carrier systems - except PVP - exhibited efficient singlet oxygen production, with ULVs reaching the highest quantum yields. The photodynamic potential of the different CH3Pc- and CF3Pc-formulations was studied using a human breast cancer cell line (MCF-7) by measuring the dark toxicity and phototoxicity after light irradiation at 655 nm. Encapsulation into ULVs and RH40 micelles exhibited the highest photodynamic efficiency for both phthalocyanines at low concentrations (0.05-1 µM). The fluorinated phthalocyanine showed enhanced photodynamic activity compared to its non-fluorinated analogue. While micellar carriers easily monomerized CH3Pc, ULV-encapsulated CF3Pc turned out to be the best candidate as efficient sensitizer for photodynamic therapy.

Poor treatment adherence, often referred to as the "silent epidemic," is a growing global issue that significantly contributes to preventable illness, premature death, and rising healthcare costs. Among compliance-enhancing strategies, controlled-release depots designed for intermediate treatment cycles represent a suitable approach, particularly in contexts where frequent dosing is impractical. Current long-acting injectable formulations, though, are often hindered by challenges in injectability, delayed onset, and complex manufacturing. Here, we present a thermoresponsive, in situ forming liposomal depot (TILD) designed to modulate the release of membrane-associated drugs following subcutaneous administration. Using buprenorphine as a model analgesic, we demonstrate that TILD responds to subcutaneous divalent cations with immediate surface-drug release and to body temperature with sustained diffusion through a fluidized bilayer. Molecular simulations guided the system design, and structural and colloidal characterizations validated its responsiveness to physiological cues. In vivo, TILD formed stable depots and maintained therapeutic drug levels for up to four days in both rats and Beagle dogs. Pharmacodynamics studies in rats confirmed the delivery of prolonged analgesia.

Potassium is essential in cellular functions, with specific importance in muscle activity and cardiovascular health. It is the main intracellular cation in the human body, with 70% located in muscle. Traditional methods to measure potassium levels are invasive and lack specificity for intracellular concentrations. Recently, non-invasive in vivo investigation of K+ ion homeostasis has become feasible by using 39K magnetic resonance imaging (MRI) and MR spectroscopy (MRS) at ultrahigh magnetic fields. However, studies demonstrating the sensitivity of 39K MRI or MRS to detect potassium alterations in disease or upon intervention are sparse. This study utilizes 39K MRS to non-invasively track real-time intramuscular potassium changes during exercise, providing an assessment of potassium dynamics and exploring the potential for technical artifacts in the measurements. Five healthy subjects (three males, two females) were recruited to perform standardized dynamic knee extensions inside a 7T MR scanner. Potassium levels were measured using a 39K MRS protocol that included periods of rest, moderate, and heavy exercise followed by recovery. Additionally, possible measurement artifacts due to muscle movement or changes in coil position relative to the thigh were evaluated using 39K MRS and 1H MRI monitoring in separate sessions. The study revealed a consistent decrease in potassium levels during both moderate and heavy exercise, with an average decrease of 5%-6%. These changes were rapidly detectable and were reversed upon cessation of exercise, indicating effective in vivo monitoring capability. Possible experimental artifacts were investigated, and the results suggested not to be responsible for the detected potassium changes during exercise. The results of the non-localized 39K MRS measurements during exercise correlated well with expected physiological changes based on previous literature. The application of 39K MRS provides a valuable non-invasive tool for studying potassium dynamics in human skeletal muscle. This technique could enhance our understanding of muscle physiology and metabolic disorders. The ability to measure these changes in real time and non-invasively highlights the potential for clinical applications, including monitoring of diseases affecting muscle and cellular metabolism.

Donation after circulatory death (DCD) provides excellent patient outcomes in heart transplantation and substantially increases graft availability. The lack of validated biomarkers for graft function constrains reliable graft assessment and highlights the need for more effective assessment strategies. Using a porcine model of DCD, hearts underwent 0 (= sham), 10, 20, or 30 minutes of warm, in situ ischemia followed by normothermic ex situ heart perfusion (ESHP) for 3 hours in an unloaded mode and then 1 hour with left ventricular (LV) loading. During unloaded perfusion, LV function and the release of cell death markers were measured at regular intervals. These potential biomarker measurements were correlated with recovery outcomes determined at the end of loaded reperfusion. During unloaded ESHP, perfusate levels of heart-type fatty acid binding protein, and several catheter-based measurements of LV function, particularly LV work (calculated as the product of heart rate and developed pressure), correlated with functional recovery outcomes (P < .05 for all). We report several new biomarkers of cardiac graft quality, such as LV function and heart-type fatty acid binding protein, that are enabled by normothermic ESHP. These biomarkers are particularly promising as they are amenable to clinical application and may improve our precision in cardiac DCD graft evaluation.

Background:With chronic liver disease (CLD) rising globally, noninvasive methods are needed to stratify early, intermediate, and advanced CLD with and without clinically significant portal hypertension (CSPH). Purpose:To analyze the combined diagnostic value of intravoxel incoherent motion (IVIM) and liver stiffness (LS) from magnetic resonance elastography (MRE) for CLD stage discrimination vs secondary single-parameter analyses. Materials and methods:This retrospective cross-sectional study included 185 patients who underwent 3T liver MRI, including MRE and IVIM, between March 2016 and November 2023. Patients with CLD were grouped based on their liver fibrosis degree into early CLD (F0-F1; n = 21), intermediate CLD (F2; n = 19), advanced CLD (F3-F4, n = 20), and advanced CLD with CSPH (n = 22). CSPH was defined as splenomegaly (>120 mm) with thrombocytopenia (<100 × 109/L), ascites, or portosystemic collaterals. Patients without CLD (n = 103) served as negative controls. IVIM parameters (tissue diffusivity D, perfusion fraction f, and pseudo-diffusion coefficient D*) and MRE LS were analyzed. Statistical analysis included the Kruskal-Wallis test and both univariate and multivariate regression. Results:In total, 185 patients (median age: 55 years, interquartile range 25%-75%: 45-63 years; 94 men) were evaluated. All parameters differed significantly between all groups (P < .001). f and D* decreased with disease progression, while LS increased. D initially decreased in patients with CLD but increased in those with CSPH. Consequently, higher D-values indicated the presence of CSPH in advanced stages (odds ratio [OR] 1.09, 95% CI 1.03-1.17, P = .009). Elevated LS values showed strong associations with the presence of CLD (OR 5.01, CI 2.25-12.65, P < .001). Combining D and LS further improved diagnostic differentiation between disease stages, especially for differentiation between advanced CLD and advanced CLD with CSPH (OR 2.41, CI 1.33-5.44, P = .01). Conclusion:IVIM and MRE are useful for characterizing CLD and CSPH. Combining D from IVIM with LS from MRE improves diagnostic accuracy compared to MRE alone.

INTRODUCTION:Metabolomic discrimination of different mitochondrial defects is challenging. We describe an NMR-based bioreactor allowing real-time intra- and extracellular metabolic investigation of perfused fibroblasts. OBJECTIVES:The objective of this study is (I) determining whether metabolic investigations of perfused fibroblasts overall and separated for intra- and extracellular contributions by real-time NMR allows for discrimination of different representative mitochondrial defects in a feasibility study and (II) gaining insight into physiological consequences of mitochondrial dysfunction in basal condition and during glycolysis inhibition. METHODS:Overall, intra- and extracellular metabolomes of malate dehydrogenase 2 (MDH2), pyruvate dehydrogenase (PDH), complex I (CI) deficient fibroblasts, and control fibroblasts were investigated under standard culture conditions and under glycolysis inhibition. In addition to "overall" metabolite quantification, intra- and extracellular metabolic contributions were separated based on diffusion rate differences. RESULTS AND DISCUSSION:Overall metabolites: Chemometric analysis of the entire metabolome revealed good separation between control, PDH and MDH2, while CI was less well separated. However, mixed intra- and extracellular changes complicated interpretation of the cellular metabolism. Intra- and extracellular metabolites: Compartment specific chemometrics revealed possibly augmenting metabolomic separation between control and deficient cell lines under basal and inhibition condition. All mitochondrial defects exhibited upregulation of glycolytic metabolism compared to controls. Inhibition of glycolysis resulted in perturbations of other metabolic pathways such as glutaminolysis, alanine, arginine, glutamate, and proline metabolism. MDH2 showed upregulation of alanine and glutamate metabolism, while the CI defect revealed lower intracellular arginine and downregulation of glutamate and arginine-dependent proline synthesis. CONCLUSION:Discrimination of intra- and extracellular metabolic contributions helps understanding the underlying mechanisms of mitochondrial disorders, uncovers potential metabolic biomarkers, and unravels metabolic pathway-specific adaptations in response to metabolic perturbations.

The oxidative phosphorylation (OXPHOS) system is intricately organized, with respiratory complexes forming super-assembled quaternary structures whose assembly mechanisms and physiological roles remain under investigation. Cox7a2l, also known as Scaf1, facilitates complex III and complex IV (CIII-CIV) super-assembly, enhancing energetic efficiency in various species. We examined the role of Cox7a1, another Cox7a family member, in supercomplex assembly and muscle physiology. Zebrafish lacking Cox7a1 exhibited reduced CIV2 formation, metabolic alterations, and non-pathological muscle performance decline. Additionally, cox7a1-'- hearts displayed a pro-regenerative metabolic profile, impacting cardiac regenerative response. The distinct phenotypic effects of cox7a1-'- and cox7a2l-'- underscore the diverse metabolic and physiological consequences of impaired supercomplex formation, emphasizing the significance of Cox7a1 in muscle maturation within the OXPHOS system.

BACKGROUND:Heart transplantation with donation after circulatory death and ex-situ heart perfusion offers excellent outcomes and increased transplantation rates. However, improved graft evaluation techniques are required to ensure effective utilization of grafts. Therefore, we investigated circulating factors, both in-situ and ex-situ, as potential biomarkers for cardiac graft quality. METHODS:Circulatory death was simulated in anesthetized male pigs with warm ischemic durations of 0, 10, 20, or 30 minutes. Hearts were explanted and underwent ex-situ perfusion for 3 hours in an unloaded mode, followed by left ventricular loading for 1 hour, to evaluate cardiac recovery (outcomes). Multiple donor blood and ex-situ perfusate samples were used for biomarker evaluation with either standard biochemical techniques or nuclear magnetic resonance spectroscopy. RESULTS:Circulating adrenaline, both in the donor and at 10 minutes ex-situ heart perfusion, negatively correlated with cardiac recovery (p < 0.05 for all). We identified several new potential biomarkers for cardiac graft quality that can be measured rapidly and simultaneously with nuclear magnetic resonance spectroscopy. At multiple timepoints during unloaded ex-situ heart perfusion, perfusate levels of acetone, betaine, creatine, creatinine, fumarate, hypoxanthine, lactate, pyruvate and succinate (p < 0.05 for all) significantly correlated with outcomes; the optimal timepoint being 60 minutes. CONCLUSIONS:In heart donation after circulatory death, circulating adrenaline levels are valuable for cardiac graft evaluation. Nuclear magnetic resonance spectroscopy is of particular interest, as it measures multiple metabolites in a short timeframe. Improved biomarkers may allow more precision and therefore better support clinical decisions about transplantation suitability.

Porphyrinic photosensitizers (PSs) and their nano-sized polymer-based carrier systems are required to exhibit low dark toxicity, avoid side effects, and ensure high in vivo tolerability. Yet, little is known about the intracellular fate of PSs during the dark incubation period and how it is affected by nanoparticles. In a systematic study, high-resolution magic angle spinning NMR spectroscopy combined with statistical analyses was used to study the metabolic profile of cultured HeLa cells treated with different concentrations of PS chlorin e4 (Ce4) alone or encapsulated in carrier systems. For the latter, either polyvinylpyrrolidone (PVP) or the micelle-forming polyethylene glycol (PEG)-polypropylene glycol triblock copolymer Kolliphor P188 (KP) were used. Diffusion-edited spectra indicated Ce4 membrane localization evidenced by Ce4 concentration-dependent chemical shift perturbation of the cellular phospholipid choline resonance. The effect was also visible in the presence of KP and PVP but less pronounced. The appearance of the PEG resonance in the cell spectra pointed towards cell internalization of KP, whereas no conclusion could be drawn for PVP that remained NMR-invisible. Multivariate statistical analyses of the cell spectra (PCA, PLS-DA, and oPLS) revealed a concentration-dependent metabolic response upon exposure to Ce4 that was attenuated by KP and even more by PVP. Significant Ce4-concentration-dependent alterations were mainly found for metabolites involved in the tricarboxylic acid cycle and the phosphatidylcholine metabolism. The data underline the important protective role of the polymeric carriers following cell internalization. Moreover, to our knowledge, for the first time, the current study allowed us to trace intracellular PS localization on an atomic level by NMR methods.

Liposomes show promise as biolubricants for damaged cartilage, but their small size results in low joint and cartilage retention. We developed a zinc ion-based liposomal drug delivery system for local osteoarthritis therapy, focusing on sustained release and tribological protection from phospholipid lubrication properties. Our strategy involved inducing aggregation of negatively charged liposomes with zinc ions to extend rapamycin (RAPA) release and improve cartilage lubrication. Liposomal aggregation occurred within 10 min and was irreversible, facilitating excess cation removal. The aggregates extended RAPA release beyond free liposomes and displayed irregular morphology influenced by RAPA. At nearly 100 µm, the aggregates were large enough to exceed the previously reported size threshold for increased joint retention. Tribological assessment on silicon surfaces and ex vivo porcine cartilage revealed the system's excellent protective ability against friction at both nano- and macro-scales. Moreover, RAPA was shown to attenuate the fibrotic response in human OA synovial fibroblasts. Our findings suggest the zinc ion-based liposomal drug delivery system has potential to enhance OA therapy through extended release and cartilage tribological protection, while also illustrating the impact of a hydrophobic drug like RAPA on liposome aggregation and morphology.

In this study, we investigated the metabolic signatures of different mitochondrial defects (two different complex I and complex V, and the one MDH2 defect) in human skin fibroblasts (HSF). We hypothesized that using a selective culture medium would cause defect specific adaptation of the metabolome and further our understanding of the biochemical implications for the studied defects. All cells were cultivated under galactose stress condition and compared to glucose-based cell culture condition. We investigated the bioenergetic profile using Seahorse XFe96 cell analyzer and assessed the extracellular metabolic footprints and the intracellular metabolic fingerprints using NMR. The galactose-based culture condition forced a bioenergetic switch from a glycolytic to an oxidative state in all cell lines which improved overall separation of controls from the different defect groups. The extracellular metabolome was discriminative for separating controls from defects but not the specific defects, whereas the intracellular metabolome suggests CI and CV changes and revealed clear MDH2 defect-specific changes in metabolites associated with the TCA cycle, malate aspartate shuttle, and the choline metabolism, which are pronounced under galactose condition.

In this study was shown the possibility to perform compartment-specific metabolic investigations of living fibroblasts in real-time using a bioreactor system within an NMR spectrometer. Cell volume and the ratio cells to extracellular medium within the sensitive region of NMR coil were evaluated for quantification purposes. The needed sensitivity to detect metabolite changes in the extracellular footprint at different flow rates was shown. The capability of diffusion technique to distinguish between compartment-specific contributions was revealed, and to detect changes in compartment-specific metabolite pools under standard or selective culture conditions, and upon inhibitor challenges.

Nuclear magnetic resonance (NMR) approaches have been described as a powerful method for measuring oxygen in tissue cultures and body fluids by using relaxation time dependencies of substances on pO2. The present NMR study describes methods to longitudinally monitor global, in situ intracellular, and spatially resolved oxygen tension in culture media and 3D cell cultures using relaxation times of water without the need to use external sensors. 1H NMR measurements of water using a modified inversion recovery pulse scheme were employed for global, i.e., intra- and extracellular oxygen estimation in an NMR-bioreactor. The combination of 1H relaxation time T1 and diffusion measurements of water was employed for in situ cellular oxygen content determination. Spatially selective water relaxation time estimations were used for spatially resolved oxygen quantification along the NMR tube length. The inclusion in a study protocol of the presented techniques for oxygen quantification, as a surrogate marker of oxidative phosphorylation (OXPHOS), provides the possibility to measure mitochondrial respiration and metabolic changes simultaneously.

Once considered a waste product of anaerobic cellular metabolism, lactate has been identified as a critical regulator of tumorigenesis, maintenance, and progression. The putative primary function of lactate dehydrogenase B (LDHB) is to catalyze the conversion of lactate to pyruvate; however, its role in regulating metabolism during tumorigenesis is largely unknown. To determine whether LDHB plays a pivotal role in tumorigenesis, we performed 2D and 3D in vitro experiments, utilized a conventional xenograft tumor model, and developed a novel genetically engineered mouse model (GEMM) of non-small cell lung cancer (NSCLC), in which we combined an LDHB deletion allele with an inducible model of lung adenocarcinoma driven by the concomitant loss of p53 (also known as Trp53) and expression of oncogenic KRAS (G12D) (KP). Here, we show that epithelial-like, tumor-initiating NSCLC cells feature oxidative phosphorylation (OXPHOS) phenotype that is regulated by LDHB-mediated lactate metabolism. We show that silencing of LDHB induces persistent mitochondrial DNA damage, decreases mitochondrial respiratory complex activity and OXPHOS, resulting in reduced levels of mitochondria-dependent metabolites, e.g., TCA intermediates, amino acids, and nucleotides. Inhibition of LDHB dramatically reduced the survival of tumor-initiating cells and sphere formation in vitro, which can be partially restored by nucleotide supplementation. In addition, LDHB silencing reduced tumor initiation and growth of xenograft tumors. Furthermore, we report for the first time that homozygous deletion of LDHB significantly reduced lung tumorigenesis upon the concomitant loss of Tp53 and expression of oncogenic KRAS without considerably affecting the animal’s health status, thereby identifying LDHB as a potential target for NSCLC therapy. In conclusion, our study shows for the first time that LDHB is essential for the maintenance of mitochondrial metabolism, especially nucleotide metabolism, demonstrating that LDHB is crucial for the survival and proliferation of NSCLC tumor-initiating cells and tumorigenesis.

The ZEUS study was a multi-center randomized controlled trial investigating the effect of early conversion from a ciclosporin-based to an everolimus-based regimen on graft function twelve months post-transplantation. In this investigator-initiated sub-study, functional magnetic resonance imaging (fMRI) of kidney grafts was prospectively performed to non-invasively assess differences in graft oxygenation, diffusion and perfusion between groups and time-points using diffusion-weighted imaging (DWI) and blood oxygen level-dependent (BOLD)-MRI. Sixteen patients underwent DWI and BOLD-MRI at months 4.5 and 12 post-transplantation on a 3 Tesla and 1.5 Tesla (n = 3) MR scanner. After exclusion due to image quality, outlier values or missing data, DWI was analyzed for ten subjects; BOLD for eight subjects. The diffusion coefficient ADCD decreased in the CsA-treated group over time, whereas it increased in the EVE group (p = 0.046, medulla). The change in ADCD from months 4.5 to 12 significantly differed between groups in the cortex (p = 0.033) and medulla (p = 0.019). In BOLD, cortico-medullary transverse relaxation rate R2* increased (decreased tissue oxygen) in the CsA-treated and decreased in EVE-treated groups over time. Similarly, R2* values at month 12 were higher in the CsA-treated group compared to the EVE-treated group. There was no significant difference for the perfusion fraction FP. In conclusion, this prospective sub-study of the ZEUS trial suggests an impact of immunosuppressive regimen on fMRI parameters of the kidney graft.

NMR flow devices provide longitudinal real-time quantitative metabolome characterisation of living cells. However, discrimination of intra- and extracellular contributions to the spectra represents a major challenge in metabolomic NMR studies. The present NMR study demonstrates the possibility to quantitatively measure both metabolic intracellular fingerprints and extracellular footprints on human control fibroblasts by using a commercially available flow tube system with a standard 5 mm NMR probe. We performed a comprehensive 3D cell culture system characterisation. Diffusion NMR was employed for intra- and extracellular metabolites separation. In addition, complementary extracellular footprints were determined. The implemented perfused NMR bioreactor system allowed the determination of 35 metabolites and intra- and extracellular separation of 19 metabolites based on diffusion rate differences. We show the reliability and sensitivity of NMR diffusion measurements to detect metabolite concentration changes in both intra- and extracellular compartments during perfusion with different selective culture media, and upon complex I inhibition with rotenone. We also demonstrate the sensitivity of extracellular footprints to determine metabolic variations at different flow rates. The current method is of potential use for the metabolomic characterisation of defect fibroblasts and for improving physiological comprehension.

Background: Because of the interplay between mitochondrial respiration and cellular metabolism, the simultaneous monitoring of both cellular processes provides important insights for the understanding of biological processes. NMR flow systems provide a unique window into the metabolome of cultured cells. Simplified bioreactor construction based on commercially available flow systems increase the practicability and reproducibility of bioreactor studies using standard NMR spectrometers. We therefore aim at establishing a reproducible NMR bioreactor system for metabolic 1H-NMR investigations of small molecules and concurrent oxygenation determination by 19F-NMR, with in depth description and validation by accompanying measures. Methods: We demonstrate a detailed and standardized workflow for the preparation and transfer of collagen based 3D cell culture of high cell density for perfused investigation in a 5 mm NMR tube. Self-constructed gas mixing station enables 5% CO2 atmosphere for physiological pH in carbon based medium and is perfused by HPLC pump. Results & Discussion: Implemented perfused bioreactor allows detection of perfusion rate dependent metabolite content. We show interleaved dynamic profiling of 26 metabolites and mitochondrial respiration. During constant perfusion, sequential injection of rotenone/oligomycin and 2-deoxy-glucose indicated immediate activation and deactivation of glycolytic rate and full inhibition of oxygen consumption. We show sensitivity to detect substrate degradation rates of major mitochondrial fuel pathways and were able to simultaneously measure cellular oxygen consumption.

Background: Kidney perfusion and oxygenation are two important determinants of kidney graft function. In kidney transplantation, repeated graft hypoperfusion may occur during hip flexion, for example in the sitting position, due to the progressive development of fibrotic tissue around iliac arteries. The aim of this study was to assess the changes in oxygenation and perfusion of kidney grafts during hip flexion and extension using a new functional magnetic resonance imaging (fMRI) protocol.Methods: Nineteen kidney graft recipients prospectively underwent MRI on a 3T scanner including diffusion-weighted, blood oxygenation level dependent (BOLD), and arterial spin labeling sequences in hip positions 0° and >90° before and after intravenous administration of 20 mg furosemide.Results: Unexpectedly, graft perfusion values were significantly higher in flexed compared to neutral hip position. Main diffusion-derived parameters were not affected by hip position. BOLD-derived cortico-medullary R2* ratio was significantly modified during hip flexion suggesting an intrarenal redistribution of the oxygenation in favor of the medulla and to the detriment of the cortex. Furthermore, the increase in medullary oxygenation induced by furosemide was significantly blunted during hip flexion (p < 0.001).Conclusion: Hip flexion has an acute impact on perfusion and tissue oxygenation in kidney grafts. Whether these position-dependent changes affect the long-term function and outcome of kidney transplants needs further investigation.

The metabolic profiling of tissue biopsies using high-resolution–magic angle spinning (HR-MAS) 1H nuclear magnetic resonance (NMR) spectroscopy may be influenced by experimental factors such as the sampling method. Therefore, we compared the effects of two different sampling methods on the metabolome of brain tissue obtained from the brainstem and thalamus of healthy goats by 1H HR-MAS NMR spectroscopy—in vivo-harvested biopsy by a minimally invasive stereotactic approach compared with postmortem-harvested sample by dissection with a scalpel. Lactate and creatine were elevated, and choline-containing compounds were altered in the postmortem compared to the in vivo-harvested samples, demonstrating rapid changes most likely due to sample ischemia. In addition, in the brainstem samples acetate and inositols, and in the thalamus samples ƴ-aminobutyric acid, were relatively increased postmortem, demonstrating regional differences in tissue degradation. In conclusion, in vivo-harvested brain biopsies show different metabolic alterations compared to postmortem-harvested samples, reflecting less tissue degradation. Sampling method and brain region should be taken into account in the analysis of metabolic profiles. To be as close as possible to the actual situation in the living individual, it is desirable to use brain samples obtained by stereotactic biopsy whenever possible.

Cisplatin (cisPt) is an important drug that is used against various cancers, including advanced lung cancer. However, drug resistance is still a major ongoing problem and its investigation is of paramount interest. Here, a high-resolution magic angle spinning (HR-MAS) NMR study is presented deciphering the metabolic profile of non-small cell lung cancer (NSCLC) cells and metabolic adaptations at different levels of induced cisPt-resistance, as well as in their de-induced counterparts (cells cultivated in absence of cisPt). In total, fifty-three metabolites were identified and quantified in the 1H-HR-MAS NMR cell spectra. Metabolic adaptations to cisPt-resistance were detected, which correlated with the degree of resistance. Importantly, de-induced cell lines demonstrated similar metabolic adaptations as the corresponding cisPt-resistant cell lines. Metabolites predominantly changed in cisPt resistant cells and their de-induced counterparts include glutathione and taurine. Characteristic metabolic patterns for cisPt resistance may become relevant as biomarkers in cancer medicine.