Intratumoral heterogeneity after targeted therapy in murine cancer models with differing degrees of malignancy.

INTRODUCTION: Conventional morphologic and volumetric assessment of treatment response is not suitable for adequately assessing responses to targeted cancer therapy. The aim of this study was to evaluate changes in tumor composition after targeted therapy in murine models of breast cancer with differing degrees of malignancy via non-invasive magnetic resonance imaging (MRI). MATERIALS AND METHODS: Mice bearing highly malignant 4T1 tumors or low malignant 67NR tumors were treated with either a combination of two immune checkpoint inhibitors (ICI, anti-PD1 and anti-CTLA-4) or the multi-tyrosine kinase inhibitor sorafenib, following experiments with macrophage-depleting clodronate-loaded liposomes and vessel-stabilizing angiopoietin-1. Mice were imaged on a 9.4 T small animal MRI system with a multiparametric (mp) protocol, comprising T1 and T2 mapping and diffusion-weighted imaging. Tumors were analyzed ex vivo with histology. RESULTS AND DISCUSSIONS: All treatments led to an increase in non-viable areas, but therapy-induced intratumoral changes differed between the two tumor models and the different targeted treatments. While ICI treatment led to intratumoral hemorrhage, sorafenib treatment mainly induced intratumoral necrosis. Treated 4T1 tumors showed increasing and extensive areas of necrosis, in comparison to 67NR tumors with only small, but also increasing, necrotic areas. After either of the applied treatments, intratumoral heterogeneity, was increased in both tumor models, and confirmed ex vivo by histology. Apparent diffusion coefficient with subsequent histogram analysis proved to be the most sensitive MRI sequence. In conclusion, mp MRI enables to assess dedicated therapy-related intratumoral changes and may serve as a biomarker for treatment response assessment.

Vasopressors for acute myocardial infarction complicated by cardiogenic shock.

Several international evidence-based guidelines reveal the lack of evidence on the treatment of patients with acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) for all recommended therapies. We included 6 studies with 842 eligible patients and one ongoing study. Three different adrenergic agents (norepinephrine, dopamine, epinephrine), vasopressin and the NOS inhibitor tilarginine were compared in 4 different combinations. On the small basis of all available evidence we can state that there is no evidence to use tilarginene, some evidence to avoid dopamine due to increased rates of arrhythmias, but some evidence, which suggests to prefer norepinephrine in comparison to epinephrine as vasopressor.

Micro-morphometrical assessment of the effect of Harpagophytum procumbens extract on articular cartilage in rabbits with experimental osteoarthritis using magnetic resonance imaging.

In vitro effects indicate a putative beneficial effect of Harpagophytum procumbens on cartilage turnover, however, in vivo protective effects on cartilage have yet to be demonstrated. A 7.1T MRI scanner was used to derive measurements of thickness, surface area and volume of the tibial condylar cartilage and to assess their precision (in the case of volume also accuracy) against the volumes of dissected cartilage measured by water displacement. Quantitative measurements were made in 16 rabbits, 6 months after unilateral medial meniscectomy and transection of the anterior cruciate ligament, after which eight of these were given a proprietary extract of Harpagophytum procumbens (HP). A semiquantitative MRI-based grading of the tibial cartilage was also compared with a 'macroscopic' grading based on direct visual inspection of dissected joints. The test-retest precision for MRI-based measurement was ≤6.4%. MRI-based measurements correlated well with volumes of surgically resected cartilage (r = 0.97, pair-wise random difference 4.2%). The medial tibial cartilage thickness and volume were about 35% smaller in the operated knees than in the non-operated contralateral knees (p < 0.05). The findings suggest that MRI is a precise and accurate tool for evaluating cartilage in a rabbit model of OA. The difference between the intact and operated knee in thickness and volume of the medial tibial cartilage was slightly but not significantly smaller in the HP-treated group than in the non-treated group.

Immunolocalization of matrix proteins in different human cartilage subtypes.

Cartilage exerts many functions in different tissues and parts of the body. Specific requirements presumably also account for a specific biochemical composition. In this study, we investigated the presence and distribution pattern of matrix components, in particular collagen types in the major human cartilages (hyaline, fibrous, and elastic cartilage) by histochemical and immunohistochemical means. Macroscopically normal articular cartilages, menisci, disci (lumbar spine), epiglottal, and tracheal tissues were obtained from donors at autopsy. Aurical and nasal cartilages were part of routine biopsy samples from tumor resection specimens. Conventional histology and immunohistochemical stainings with collagen types I, II, III, IV, V, VI, and X and S-100 protein antibodies were performed on paraformaldehyde-fixed and paraffin-embedded specimens. The extracellular matrix is the functional component of all cartilages as indicated by the low cell densities. In particular major scaffold forming collagen types I (in fibrous cartilage) and II (in hyaline and elastic cartilages) as well as collagen type X (in the calcified layer of articular cartilages, the inner part of tracheal clips, and epiglottis cartilage) showed a specific distribution. In contrast, the "minor" collagen types III, V, and VI were found in all, collagen type IV in none of the cartilage subtypes. In this study, we present a biochemical profile of the major cartilage types of the human body which is important for understanding the physiology and the pathophysiology of cartilages.

Increase in degraded collagen type II in synovial fluid early in the rabbit meniscectomy model of osteoarthritis.

OBJECTIVE: The objective of this study was to determine whether collagen type II breakdown products in synovial fluid (SF), detected by an enzyme-linked immunoassay, represent a useful marker for early events in osteoarthritis (OA) in the rabbit medial meniscectomy model. DESIGN: Complete medial meniscectomy was performed on the right knee joints of 32 rabbits. Balanced groups of rabbits were then sacrificed at 2, 4, 8, and 12 weeks post-surgery. An additional 8 unoperated and 11 sham-operated animals served as controls. SF lavages were performed on right and left knee joints of the same animals at sacrifice. The proteolytic epitope of type II collagen was monitored using an enzyme-linked immunoassay. RESULTS: Macroscopically visible surface fibrillation and focal erosions appeared as early as 2 weeks after meniscectomy in the femorotibial joint (P<0.01). OA developed gradually during the later observation period, and then predominantly on the medial tibial plateau and medial femur. Significant histological alterations in cartilage, including a loss of proteoglycans, surface irregularities, and clefts, were detected at 2 weeks after meniscectomy (P<0.01). Collagen type II epitope levels in SF lavage samples were elevated peaking at 2 weeks after meniscectomy (P<0.02). Levels decreased at later time points, but they were still raised at 12 weeks (P< or =0.05). Highly significant correlations were found between the SF collagen type II epitope levels and the macroscopic and microscopic scoring results (Spearman rho correlation coefficient, macroscopy-collagen type II epitope r=0.222, P=0.025; microscopy-collagen type II epitope r=0.436, P< or =0.01). CONCLUSION: In this rabbit model of medial meniscectomy, levels of type II collagen fragments in SF appear to provide a useful marker of the early degenerative changes.

Can magnetization transfer magnetic resonance imaging follow proteoglycan depletion in articular cartilage?

In this study we determined the efficiency of magnetization transfer magnetic resonance imaging (MT-MRI) to differentiate native and enzymatically degraded cartilage, using bovine sesamoid bones from the metacarpophalangeal joint as a model system. Gradual proteoglycan (PG) depletion was achieved by increasing incubation periods with testicular hyaluronidase. For native cartilage a Ms/Mo ratio of 0.303 +/- 0.09 (mean +/- SEM) was measured. Biochemically determined PG diminution up to 50% correlated strongly (r = 0.953) with changes in the Ms/Mo ratio. Further PG loss is not reflected in an equally drastic Ms/Mo increase, whereas subsequent treatment of PG-depleted cartilage samples with collagenase led to an additional rise in the Ms/Mo ratio. Proteoglycan depletion and the beginning destruction of the collagen structure were also assessed histochemically. Our study confirms that collagen contributes to the baseline MT effect observed in articular cartilage. However, the changes in the MT ratio in gradually PG-depleted cartilage with a largely intact collagen network indicate that PG contributes to the MT effect as well. Therefore MT-MRI might become a sensitive technique for the monitoring of subtle degradational changes in articular cartilage, the still inaccessible process in osteoarthritis.