Long-term effects of the COVID-19 pandemic for patients with cancer.

INTRODUCTION: Long COVID is defined as the continuation of symptoms, unexplainable by alternative diagnosis, longer than four weeks after SARS-CoV-2 infection. These symptoms might hinder daily activities and overall well-being, ultimately impacting quality of life (QoL). Several studies have reported fatigue as the most common symptom, followed by dyspnoea, headache and myalgia. Although it is assumed that long COVID affects 10-20% of SARS-CoV-2 infected individuals, recently numbers up to 60% were described for patients with cancer. This study uncovers the impact of the COVID-19 pandemic on QoL of patients with cancer and how long COVID manifests in this cohort. METHODS: A group of 96 patients with cancer was followed from March 2022 till March 2023. Online questionnaires assessing symptoms associated with long COVID, anxiety and depression (HADS), quality of life (EORTC-QLQ-C30) and cognitive functioning (CFQ) were sent every three months during this period. Furthermore, a semi-structured focus group was organised for qualitative data collection. RESULTS: Overall, these patients reported a negative impact of the enforced COVID-19 restrictions on the emotional and psychological wellbeing. Forty nine patients with cancer (51.0%) were infected with SARS-CoV-2 over the course of the study, of which 39 (79.6%) reported long COVID symptoms. The most commonly reported symptoms were myalgia (46.2%), fatigue (38.5%) and disturbed sleep (35.9%) and it was observed that male sex is associated with poor long COVID outcomes. CONCLUSION: While patients with cancer experience similar long COVID symptoms as healthy controls, the prevalence is remarkably higher possibly due to their compromised immune system and weakened physiological reserve.

Since the outbreak in Wuhan (China) at the end of 2019, the Coronavirus Disease 2019 (COVID-19) pandemic has caused instability at various levels of society. While most patients completely recover from their SARS-CoV-2 infection, 10­20% of infected persons and up to 60% of infected patients with cancer develop long COVID. Long COVID is defined as the continuation of symptoms, which cannot be explained by alternative causes, that last longer than four weeks after initial infection. Even though it is generally accepted that patients with cancer are at increased risk of developing severe COVID-19, it is still unclear how long COVID manifests and whether long COVID impacts quality of life in this cohort. Hence, this study observed that patients with cancer reported a negative impact of the enforced COVID-19 restrictions on the emotional and psychological wellbeing. While patients with cancer experience similar long COVID symptoms as healthy controls, the prevalence is remarkably higher possibly due to their compromised immune system and weakened physiological reserve.

A real-world analysis on the efficacy and tolerability of liposomal irinotecan plus 5-fluorouracil and folinic acid in metastatic pancreatic ductal adenocarcinoma in Belgium.

Background: Currently, nanoliposomal irinotecan (nal-IRI) + 5-fluorouracil/folinic acid (5-FU/LV) is the only approved second-line treatment for patients suffering from metastatic pancreatic ductal adenocarcinoma (mPDAC). However, also other chemotherapeutic regimens are used in this setting and due to the lack of clear real-world data on the efficacy of the different regimens, there is no consensus on the optimal treatment sequence for mPDAC patients. Objectives: To provide information on the safe and efficacious use of nal-IRI + 5-FU/LV in clinical practice in Belgium, which is needed for healthcare professionals to estimate the risk-benefit ratio of the intervention. Methods: Medical data of adult patients with mPDAC who were treated with nal-IRI + 5-FU/LV in one of the participating Belgian hospitals were retrospectively collected. Kaplan-Meier analysis was performed to obtain survival curves to estimate the median overall survival (OS) and progression-free survival (PFS). All other results were presented descriptively. Results: A total of 56 patients [median age at diagnosis: 69 years (range 43 years), 57.1% male] were included. Patients received a median of 5 (range 49 cycles) nal-IRI + 5-FU/LV cycles, extended over 10 weeks (range 130.8 weeks). The median start dose for nal-IRI was 70 mg/m² (range 49.24 mg/m²) and chemotherapy dose reduction and delay occurred in, respectively, 42.8% and 37.5% of the patients. The median OS was 6.8 months (95% CI: 5.6-8.4 months) with a 6-month survival rate of 57.4% and a 1-year survival rate of 27.8% in the overall study population. The median OS for patients treated with nal-IRI as second-line therapy or as later-line treatment was, respectively, 6.8 months (95% CI: 5.9-7.0 months) and 5.6 months (95% CI: 4.2-no upper limit). In the overall study population, a median PFS of 3.1 months (95% CI: 2.4-4.6 months) and a disease control rate of 48.3%, comprising 30.4% stable disease, 16.1% partial and 1.8% complete response, was observed. The median PFS for patients treated with nal-IRI as second-line therapy was 3.9 months (95% CI: 2.8-4.8 months) while this was 2.4 months (95% CI: 1.9-9.1 months) for those that received nal-IRI in a later-line treatment. In terms of safety, gastrointestinal problems occurred most (64.3% of the patients) and from all reported treatment emergent adverse events, 39.2% were grade 3 or 4. Conclusion: Nal-IRI + 5-FU/LV is a valuable, effective, and safe sequential treatment option following gemcitabine-based therapy in patients with mPDAC. Trial details: Retrospective study on the efficacy and tolerability of liposomal irinotecan (NALIRI); ClinicalTrials.gov Identifier: NCT0509506 (https://clinicaltrials.gov/ct2/show/NCT05095064?term=naliri&draw=2&rank=2).

NPY Methylated ctDNA is a Promising Biomarker for Treatment Response Monitoring in Metastatic Colorectal Cancer.

PURPOSE: Analysis of methylation markers in liquid biopsies is a promising technique for the follow-up of patients with metastatic colorectal cancer (mCRC), because they can be used in all patients, regardless of their mutational status. Therefore, we studied the value of NPY methylation analysis in circulating tumor DNA (ctDNA) for accurate response monitoring in patients with mCRC in the PANIB trial. EXPERIMENTAL DESIGN: The PANIB trial was a randomized phase II trial designed to compare FOLFOX plus panitumumab and FOLFOX plus bevacizumab in patients with RAS wild-type unresectable mCRC. The results of sequential liquid biopsies were correlated with results of imaging. RESULTS: Forty patients were included from six Belgian hospitals. Analysis of the liquid biopsies revealed that higher baseline levels of methylated ctDNA was associated with a significantly shorter overall survival [HR, 1.015; 95% confidence interval (CI), 1.005-1.025; P = 0.002]. Furthermore, 37 patients provided at least two liquid biopsies. Thirty-one of them showed a decrease in the methylation ratio after the start of therapy, which corresponded with stable disease or response on imaging at the first evaluation. When comparing the panitumumab and bevacizumab arm, significantly higher objective response and early tumor shrinkage rates were observed in the panitumumab arm (P = 0.048 and 0.015, respectively). However, due to a small study population, the trial was underpowered to detect a significant difference in survival. CONCLUSIONS: The results of this study confirm that baseline methylated ctDNA is a prognostic marker and indicate that NPY methylation is a promising marker for response monitoring in patients with mCRC.

Humoral and Cellular Immune Responses against SARS-CoV-2 after Third Dose BNT162b2 following Double-Dose Vaccination with BNT162b2 versus ChAdOx1 in Patients with Cancer.

PURPOSE: Patients with cancer display reduced humoral responses after double-dose COVID-19 vaccination, whereas their cellular response is more comparable with that in healthy individuals. Recent studies demonstrated that a third vaccination dose boosts these immune responses, both in healthy people and patients with cancer. Because of the availability of many different COVID-19 vaccines, many people have been boosted with a different vaccine from the one used for double-dose vaccination. Data on such alternative vaccination schedules are scarce. This prospective study compares a third dose of BNT162b2 after double-dose BNT162b2 (homologous) versus ChAdOx1 (heterologous) vaccination in patients with cancer. EXPERIMENTAL DESIGN: A total of 442 subjects (315 patients and 127 healthy) received a third dose of BNT162b2 (230 homologous vs. 212 heterologous). Vaccine-induced adverse events (AE) were captured up to 7 days after vaccination. Humoral immunity was assessed by SARS-CoV-2 anti-S1 IgG antibody levels and SARS-CoV-2 50% neutralization titers (NT50) against Wuhan and BA.1 Omicron strains. Cellular immunity was examined by analyzing CD4+ and CD8+ T-cell responses against SARS-CoV-2-specific S1 and S2 peptides. RESULTS: Local AEs were more common after heterologous boosting. SARS-CoV-2 anti-S1 IgG antibody levels did not differ significantly between homologous and heterologous boosted subjects [GMT 1,755.90 BAU/mL (95% CI, 1,276.95-2,414.48) vs. 1,495.82 BAU/mL (95% CI, 1,131.48-1,977.46)]. However, homologous-boosted subjects show significantly higher NT50 values against BA.1 Omicron. Subjects receiving heterologous boosting demonstrated increased spike-specific CD8+ T cells, including higher IFNγ and TNFα levels. CONCLUSIONS: In patients with cancer who received double-dose ChAdOx1, a third heterologous dose of BNT162b2 was able to close the gap in antibody response.

Predictive model for BNT162b2 vaccine response in cancer patients based on blood cytokines and growth factors.

Background: Patients with cancer, especially hematological cancer, are at increased risk for breakthrough COVID-19 infection. So far, a predictive biomarker that can assess compromised vaccine-induced anti-SARS-CoV-2 immunity in cancer patients has not been proposed. Methods: We employed machine learning approaches to identify a biomarker signature based on blood cytokines, chemokines, and immune- and non-immune-related growth factors linked to vaccine immunogenicity in 199 cancer patients receiving the BNT162b2 vaccine. Results: C-reactive protein (general marker of inflammation), interleukin (IL)-15 (a pro-inflammatory cytokine), IL-18 (interferon-gamma inducing factor), and placental growth factor (an angiogenic cytokine) correctly classified patients with a diminished vaccine response assessed at day 49 with >80% accuracy. Amongst these, CRP showed the highest predictive value for poor response to vaccine administration. Importantly, this unique signature of vaccine response was present at different studied timepoints both before and after vaccination and was not majorly affected by different anti-cancer treatments. Conclusion: We propose a blood-based signature of cytokines and growth factors that can be employed in identifying cancer patients at persistent high risk of COVID-19 despite vaccination with BNT162b2. Our data also suggest that such a signature may reflect the inherent immunological constitution of some cancer patients who are refractive to immunotherapy.

EVALUATION OF A SUPERVISED PHYSICAL ACTIVITY PROGRAMME FOR CANCER SURVIVORS: FROM TREATMENT TO TRIATHLON.

OBJECTIVE: It is recommended that cancer survivors incorporate physical activity into their daily lives after in-hospital rehabilitation. However, there is a lack of training programmes focusing on the specific needs of cancer survivors. TriaGO! - an 8-month intervention study of aerobic endurance training for cancer survivors - was therefore examined. The training programme aims to meet the participants' physical needs and provide socio-emotional support, in the form of an exercise programme that challenges participants to aim to compete in an Olympic- distance triathlon (1,000 m swimming, 45 km cycling, 10 km running) after 8 months' of training. METHODS: The TriaGO! training programme was provided to in-hospital rehabilitated cancer survivors (n = 12). Each patient invited a healthy friend or family member to train with them (a so called buddy (n = 12)). The 8-month programme involves supervised training sessions, combining cycling, swimming and running, which progress in frequency, duration and intensity. Physical health was measured at the start, 4 and 8 months, using objective parameters of aerobic fitness, muscular fitness and body composition. RESULTS: A total of 22 out of 24 participants successfully completed the training programme and the triathlon. Both the cancer survivors and their buddies showed significant improvements in physical health. Cancer survivors showed improvements in aerobic fitness, as increases in VO2max and VO2peak of 5.5 ml.kg-1.min-1 and 0.26 ml.min-1 respectively (p <0.0001). Buddies underwent similar significant increases; 5.39 ml.kg-1.min-1 and 0.18 ml.min-1, respectively. CONCLUSION: The TriaGO! training programme introduces the concept of supervised endurance training for cancer survivors. Through measurement of ob-jective parameters, this study demonstrated that significant physical reconditioning is possible in cancer survivors. A supervised programme would be recommended for all cancer patients after in-hospital treatment, in order to facilitate the transition to incorporation of physical activity into daily life.

Patient-reported outcome measures (PROMs) in the management of lung cancer: A systematic review.

Lung cancer is often associated with a poor quality of life, as reflected by patient-reported outcome measures (PROMs). The aim of this paper is to describe and compare the PROMs that are available. In this manuscript, we review the impact of PROMs on the management of lung cancer. Quality of the study and risk of bias were assessed using the appraisal tools recommended by the Dutch Cochrane Center. Out of 51 studies included in this review, ten instruments were identified and categorized as either generic, cancer- or lung cancer-specific. PROMs are primarily applied in scientific research to compare the therapy outcomes and in drug development to support labeling claims. The interest for the routine use of PROMs in daily practice is growing, which has positive effects on the communication with the patient, mutual decision making and the monitoring and managing of the patient. Besides that, PROMs have an independent prognostic value for survival in lung cancer and economic evaluations can be conducted using their results. Electronic platforms simplify the implementation of PROMs in the daily clinic. The EORTC QLQ-C30 and its lung cancer-specific module QLQ-LC13 are the most frequently used instruments in lung cancer patients. PROMs have the potential to improve the quality of care with a proper implementation in the routine practice. PROMS are needed to value and understand the experience of the patient.

Cachexia in cancer: what is in the definition?

OBJECTIVE: This study aimed to provide evidence-based results on differences in overall survival (OS) rate to guide the diagnosis of cancer cachexia. DESIGN: Data collection and clinical assessment was performed every 3 months (5 visits): baseline data, muscle strength, nutritional and psychosocial status. 2 definitions on cachexia using different diagnostic criteria were applied for the same patient population. Fearon et al's definition is based on weight loss, body mass index (BMI) and sarcopenia. Evans et al nuances the contribution of sarcopenia and attaches additional attention to abnormal biochemistry parameters, fatigue and anorexia. The mean OS rates were compared between patients with and without cachexia for both definitions. RESULTS: Based on the population of 167 patients who enrolled, 70% developed cachexia according to Fearon et al's definition and 40% according to Evans et al's definition. The OS in the cachectic population is 0.97 and 0.55 years, respectively. The difference in OS between patients with and without cachexia is more significant using the diagnostic criteria of Evans et al. The focus of Fearon et al on weight loss and sarcopenia over-rates the assignment of patients to the cachectic group and OS rates have less prognostic value. CONCLUSION: This study presents a correlation with prognosis in favour of Evans et al' definition as a tool for cachexia diagnosis. This means that weight loss and BMI decline are both key factors in patients with cancer leading to cachexia but less decisive as stated by Fearon et al. Instead, extra factors gain importance in order to predict survival, such as chronic inflammation, anaemia, protein depletion, reduced food intake, fatigue, decreased muscle strength and lean tissue depletion. TRIAL REGISTRATION NUMBER: B300201112334.

Elastin fragmentation in atherosclerotic mice leads to intraplaque neovascularization, plaque rupture, myocardial infarction, stroke, and sudden death.

AIMS: There is a need for animal models of plaque rupture. We previously reported that elastin fragmentation, due to a mutation (C1039G(+/-)) in the fibrillin-1 (Fbn1) gene, promotes atherogenesis and a highly unstable plaque phenotype in apolipoprotein E deficient (ApoE(-/-)) mice on a Western-type diet (WD). Here, we investigated whether plaque rupture occurred in ApoE(-/-)Fbn1(C1039G+/-) mice and was associated with myocardial infarction, stroke, and sudden death. METHODS AND RESULTS: Female ApoE(-/-)Fbn1(C1039G+/-) and ApoE(-/-) mice were fed a WD for up to 35 weeks. Compared to ApoE(-/-) mice, plaques of ApoE(-/-)Fbn1(C1039G+/-) mice showed a threefold increase in necrotic core size, augmented T-cell infiltration, a decreased collagen I content (70 ± 10%), extensive neovascularization, intraplaque haemorrhage, and a significant increase in matrix metalloproteinase-2, -9, -12, and -13 expression or activity. Plaque rupture was observed in 70% of ascending aortas and in 50% of brachiocephalic arteries of ApoE(-/-)Fbn1(C1039G+/-) mice. In ApoE(-/-) mice, plaque rupture was not seen in ascending aortas and only in 10% of brachiocephalic arteries. Seventy percent of ApoE(-/-)Fbn1(C1039G+/-) mice died suddenly, whereas all ApoE(-/-) mice survived. ApoE(-/-)Fbn1(C1039G+/-) mice showed coronary plaques and myocardial infarction (75% of mice). Furthermore, they displayed head tilt, disorientation, and motor disturbances (66% of cases), disturbed cerebral blood flow (73% of cases; MR angiograms) and brain hypoxia (64% of cases), indicative of stroke. CONCLUSIONS: Elastin fragmentation plays a key role in plaque destabilization and rupture. ApoE(-/-)Fbn1(C1039G+/-) mice represent a unique model of acute plaque rupture with human-like complications.

Magnetization transfer contrast imaging reveals amyloid pathology in Alzheimer's disease transgenic mice.

The presence of amyloid plaques in the brain is one of the pathological hallmarks of Alzheimer's disease, which might already be present in the early stage of the disease. Therefore it is important to track amyloid plaques as early as possible. In this paper, we report magnetization transfer contrast magnetic resonance imaging (MTC MRI) as a novel approach to detect amyloid plaques in vivo. Two mice models, APP/PS1 and BRI, developing amyloid pathology were investigated with MTC MRI, T2 relaxation measurements and immunohistochemistry (IHC). MT-ratios of several brain regions were compared to T2-values and correlated with quantitative IHC, revealing amyloid load and gliosis in different brain regions. APP/PS1 mice develop large compact plaques, resembling late stage Alzheimer's disease, while rather small and diffuse plaques are deposited in BRI mice, reflecting early stage of Alzheimer's disease. We found significantly higher MT-ratio's in the brain of APP/PS1 mice as compared to their controls and similar trends in BRI mice. A region based MT-ratio and IHC analysis and correlations between MT-ratios and quantitative IHC indicate amyloid plaques as the main substrate for altered MT-ratios in transgenic animals. We additionally demonstrated the improved sensitivity of MTC MRI to amyloid pathology as compared to traditional T2 relaxation measurements. Our results suggest that MTC MRI reveals extensive, and potentially even early amyloid pathology. Further unraveling the MT-effect of each pathological feature during each stage of AD might indicate MTC MRI as a useful diagnostic technique.

Resting state FMRI reveals diminished functional connectivity in a mouse model of amyloidosis.

INTRODUCTION: Functional connectivity (FC) studies have gained immense popularity in the evaluation of several neurological disorders, such as Alzheimer's disease (AD). AD is a complex disorder, characterised by several pathological features. The problem with FC studies in patients is that it is not straightforward to focus on a specific aspect of pathology. In the current study, resting state functional magnetic resonance imaging (rsfMRI) is applied in a mouse model of amyloidosis to assess the effects of amyloid pathology on FC in the mouse brain. METHODS: Nine APP/PS1 transgenic and nine wild-type mice (average age 18.9 months) were imaged on a 7T MRI system. The mice were anesthetized with medetomidine and rsfMRI data were acquired using a gradient echo EPI sequence. The data were analysed using a whole brain seed correlation analysis and interhemispheric FC was evaluated using a pairwise seed analysis. Qualitative histological analyses were performed to assess amyloid pathology, inflammation and synaptic deficits. RESULTS: The whole brain seed analysis revealed an overall decrease in FC in the brains of transgenic mice compared to wild-type mice. The results showed that interhemispheric FC was relatively preserved in the motor cortex of the transgenic mice, but decreased in the somatosensory cortex and the hippocampus when compared to the wild-type mice. The pairwise seed analysis confirmed these results. Histological analyses confirmed the presence of amyloid pathology, inflammation and synaptic deficits in the transgenic mice. CONCLUSIONS: In the current study, rsfMRI demonstrated decreased FC in APP/PS1 transgenic mice compared to wild-type mice in several brain regions. The APP/PS1 transgenic mice had advanced amyloid pathology across the brain, as well as inflammation and synaptic deficits surrounding the amyloid plaques. Future studies should longitudinally evaluate APP/PS1 transgenic mice and correlate the rsfMRI findings to specific stages of amyloid pathology.

Diffusion kurtosis imaging to detect amyloidosis in an APP/PS1 mouse model for Alzheimer's disease.

PURPOSE: Amyloid deposition in the brain is considered an initial event in the progression of Alzheimer's disease. We hypothesized that the presence of amyloid plaques in the brain of APP/presenilin 1 mice leads to higher diffusion kurtosis measures due to increased microstructural complexity. As such, our purpose was to provide an in vivo proof of principle for detection of amyloidosis by diffusion kurtosis imaging (DKI). METHODS: APPKM670/671NL /presenilin 1 L166P mice (n = 5) and wild-type littermates (n = 5) underwent DKI at the age of 16 months. Averaged diffusion and diffusion kurtosis parameters were obtained for multiple regions (hippocampus-cortex-thalamus-cerebellum). After DKI, mice were sacrificed for amyloid staining. RESULTS: Histograms of the frequency distribution of the DKI parameters tended to shift to higher values. After normalization of absolute values to the cerebellum, a nearly plaque-free region, mean, radial, and axial diffusion kurtosis were significantly higher in APP/presenilin 1 mice as compared to wild-type in the cortex and thalamus, regions demonstrating substantial amyloid staining. CONCLUSION: The current study, although small-scale, suggests increased DKI metrics, in the absence of alterations in diffusion tensor imaging metrics in the cortex and thalamus of APP/presenilin 1 mice with established amyloidosis. These results warrant further investigations on the potential of DKI as a sensitive marker for Alzheimer's disease.

Labeling of Luciferase/eGFP-expressing bone marrow-derived stromal cells with fluorescent micron-sized iron oxide particles improves quantitative and qualitative multimodal imaging of cellular grafts in vivo.

PURPOSE: Development of multimodal imaging strategies is currently of utmost importance for the validation of preclinical stem cell therapy studies. PROCEDURES: We performed a combined labeling strategy for bone marrow-derived stromal cells (BMSC) based on genetic modification with the reporter genes Luciferase and eGFP (BMSC-Luc/eGFP) and physical labeling with blue fluorescent micron-sized iron oxide particles (MPIO) in order to unambiguously identify BMSC localization, survival, and differentiation following engraftment in the central nervous system of mice by in vivo bioluminescence (BLI) and magnetic resonance imaging and postmortem histological analysis. RESULTS: Using this combination, a significant increase of in vivo BLI signal was observed for MPIO-labeled BMSC-Luc/eGFP. Moreover, MPIO labeling of BMSC-Luc/eGFP allows for the improved identification of implanted cells within host tissue during histological observation. CONCLUSIONS: This study describes an optimized labeling strategy for multimodal stem cell imaging resulting in improved quantitative and qualitative detection of cellular grafts.

Clinical potential of intravenous neural stem cell delivery for treatment of neuroinflammatory disease in mice?

While neural stem cells (NSCs) are widely expected to become a therapeutic agent for treatment of severe injuries to the central nervous system (CNS), currently there are only few detailed preclinical studies linking cell fate with experimental outcome. In this study, we aimed to validate whether IV administration of allogeneic NSC can improve experimental autoimmune encephalomyelitis (EAE), a well-established animal model for human multiple sclerosis (MS). For this, we cultured adherently growing luciferase-expressing NSCs (NSC-Luc), which displayed a uniform morphology and expression profile of membrane and intracellular markers, and which displayed an in vitro differentiation potential into neurons and astrocytes. Following labeling with green fluorescent micron-sized iron oxide particles (f-MPIO-labeled NSC-Luc) or lentiviral transduction with the enhanced green fluorescent protein (eGFP) reporter gene (NSC-Luc/eGFP), cell implantation experiments demonstrated the intrinsic survival capacity of adherently cultured NSC in the CNS of syngeneic mice, as analyzed by real-time bioluminescence imaging (BLI), magnetic resonance imaging (MRI), and histological analysis. Next, EAE was induced in C57BL/6 mice followed by IV administration of NSC-Luc/eGFP at day 7 postinduction with or without daily immunosuppressive therapy (cyclosporine A, CsA). During a follow-up period of 20 days, the observed clinical benefit could be attributed solely to CsA treatment. In addition, histological analysis demonstrated the absence of NSC-Luc/eGFP at sites of neuroinflammation. In order to investigate the absence of therapeutic potential, BLI biodistribution analysis of IV-administered NSC-Luc/eGFP revealed cell retention in lung capillaries as soon as 1-min postinjection, resulting in massive inflammation and apoptosis in lung tissue. In summary, we conclude that IV administration of NSCs currently has limited or no therapeutic potential for neuroinflammatory disease in mice, and presumably also for human MS. However, given the fact that grafted NSCs have an intrinsic survival capacity in the CNS, their therapeutic exploitation should be further investigated, and-in contrast to several other reports-will most likely be highly complex.

In vivo morphological changes in animal models of amyotrophic lateral sclerosis and Alzheimer's-like disease: MRI approach.

Magnetic resonance imaging (MRI) is the only noninvasive technique that provides structural information on both cell loss and metabolic changes. After reviewing all the results obtained in clinical studies, reliable biomarkers in neurological diseases are still lacking. Diffusional MRI, MR spectroscopy, and the assessment of regional atrophy are promising approaches, but they cannot be simultaneously used on a single patient. Thus, for further research progress, reliable animal models are needed. To this aim, we have used the clinical MRI to assess neurodegenerative processes in the hSOD-1(G93A) ALS rat model and in the trimethyltin (TMT)-treated model of Alzheimer's-like disease. T2-weighted (T2W) hyperintensive neurodegenerative foci were found in the brainstem of the ALS rat with apparent lateral ventricle dilation (T1W-hypointensity vs. T2W-hyperintensity). Degenerative processes in these areas were also confirmed by confocal images of GFAP-positive astrogliosis. MRI after i.v.i. of magnetic anti-CD4 antibodies indicated an accumulation of inflammatory cells near dilated ventricles. TMT-treated rats also revealed the dilation of lateral ventricles. Expected deterioration in the hippocampus was not observed by clinical MRI, but immunocytochemistry could reveal significant redistribution of macro- and microglia in this structure. In both models, Gd-DTPA contrast revealed a compromised blood brain barrier that may serve as the passage for inflammatory immune cells in the vicinity of dilated lateral ventricles. Moreover, in both models the midbrain region of the dorsal hippocampus was the target of BBB compromise, thus revealing a potentially vulnerable point that can be the primary target of neurodegeneration in the central nervous system.

Assessment of the neovascular permeability in glioma xenografts by dynamic T(1) MRI with Gadomer-17.

The uptake of Gadomer-17, as probed by fast dynamic T(1) measurements, was used to assess the vascular permeability surface-area product per leakage volume of tissue (k(Tofts)) of human glioma xenografts implanted in mice. With this approach we could discriminate between two types of glioma xenograft lines with a known difference in the perfused vascular architecture and degree of hypoxia. The T(1) data were analyzed according to the Tofts-Kermode compartment model. The fast-growing E102 tumor demonstrated a homogeneous distribution of the vascular permeability surface area across the tumor (mean k(Tofts) value = 0.18 +/- 0.05 min(-1)). The slowly growing E106 tumor showed a more heterogeneous pattern. Three perfused tumor areas with differences in vascular permeability surface area could be distinguished: a well-perfused periphery with high k(Tofts) values (0.24 +/- 0.04 min(-1)), perfused capillaries inside the tumor with low k(Tofts) values (0.108 +/- 0.026 min(-1)), and perfused capillaries adjacent to necrotic regions with high k(Tofts) values (0.29 +/- 0.10 min(-1)). On a different series of tumors, the hypoxic fractions were measured, and these were significantly higher in E106 tumors (0.14 +/- 0.05) compared to tumors of the E102 line (0.03 +/- 0.02).