Pehr Rissler

Mesenchymal stromal cells from primary osteosarcoma are non-malignant and strikingly similar to their bone marrow counterparts.

Mesenchymal stromal cells (MSC) are multipotent cells that can be isolated from a number of human tissues. In cancer, MSC have been implicated with tumor growth, invasion, metastasis, drug resistance and were even suggested as possible tumor‐initiating cells in osteosarcoma (OS). However, MSC from OS and their possible tumor origin have not yet been thoroughly investigated. Therefore, primary OS mesenchymal progenitors and OS‐derived MSC were studied. OS samples contained very high frequencies of mesenchymal progenitor cells as measured by the colony‐forming unit fibroblast (CFU‐F) assay (median: 1,117 colonies per 105 cells, range: 133–3,000, n = 6). This is considerably higher compared to other human tissues such as normal bone marrow (BM) (1.3 ± 0.2 colonies per 105 cells, n = 8). OS‐derived MSC (OS‐MSC) showed normal MSC morphology and expressed the typical MSC surface marker profile (CD105/CD73/CD90/CD44/HLA‐classI/CD166 positive, CD45/CD34/CD14/CD19/HLA‐DR/CD31 negative). Furthermore, all OS‐MSC samples could be differentiated into the osteogenic lineage, and all but one sample into adipocytes and chondrocytes. Genetic analysis of OS‐MSC as well as OS‐derived spheres showed no tumor‐related chromosomal aberrations. OS‐MSC expression of markers related to tumor‐associated fibroblasts (fibroblast surface protein, alpha‐smooth muscle actin, vimentin) was comparable to BM‐MSC and OS‐MSC growth was considerably affected by tyrosine kinase inhibitors. Taken together, our results demonstrate that normal, non‐malignant mesenchymal stroma cells are isolated from OS when MSC culture techniques are applied. OS‐MSC represent a major constituent of the tumor microenvironment, and they share many properties with BM‐derived MSC.

A prognostic model for soft tissue sarcoma of the extremities and trunk wall based on size, vascular invasion, necrosis, and growth pattern

In soft tissue sarcoma, better distinction of high‐risk and low‐risk patients is needed to individualize treatment and improve survival. Prognostic systems used in clinical practice identify high‐risk patients based on various factors, including age, tumor size and depth, histological type, necrosis, and grade.

Adjuvant radiotherapy in retroperitoneal sarcomas. A Scandinavian Sarcoma Group study of 97 patients

Abstract Background. Currently there is no consensus on the use of adjuvant radiotherapy (RT) in retroperitoneal sarcoma (RPS). We have analysed clinical outcomes in patients with localised RPS treated at two Scandinavian Sarcoma Group (SSG) centres: Haukeland University Hospital (HUH), Bergen, Norway and Skåne University Hospital (SUH), Lund, Sweden to clarify the effects of adjuvant RT on local control and overall survival (OS). Material and methods. Local databases and registers at HUH and SUH as well as the SSG central register were used to identify RPS patients. Patients with localised RPS who underwent surgery in Bergen between 1988 and 2009 and in Lund from 1998 to 2009 were included. Medical records were examined for clinical data, tumour characteristics, treatment factors and follow-up status. Archived tumour sections and tumour tissue were reviewed, and when necessary, restained and reclassified. Cox regression was used to analyse the association of potential prognostic factors with local recurrence-free survival (LRFS), metastasis-free survival (MFS) and OS. Results. The study included 97 patients: 52 from Norway and 45 from Sweden. The proportion of high-grade tumours was 73%. The five-year LRFS, MFS and OS were 55%, 59% and 60%, respectively. RT was significantly associated with improved local control resulting in a five-year LRFS of 77% compared with 39% without (p < 0.001). Furthermore, five-year OS was 71% in the RT group in contrast to 52% with surgery alone (p = 0.019). In the adjusted analysis RT proved to be a significant factor also for MFS (HR = 0.42, 95% CI 0.20–0.88, p = 0.021). In addition, high-grade malignancy, large tumour and positive surgical margin were risk factors for local recurrence. High malignancy grade was the only significant adverse prognostic factor for metastasis. High age and high-grade malignancy were negative prognostic factors for OS. Conclusion. Adjuvant RT was significantly associated with an improved five-year LRFS and OS.

Increased tissue endothelin-1 and endothelin-B receptor expression in temporal arteries from patients with giant cell arteritis.

PURPOSE Endothelin (ET)-1 has been implicated in the atherosclerotic process and during inflammation. Similarity in the development process of giant cell arteritis (GCA) and atherosclerosis exists. Several ET receptor antagonists have been developed, principally to target cardiovascular disease states. High doses of corticosteroids currently are used in the treatment of GCA, whereas other treatments are not as reliably effective. The present study was performed to elucidate the role for ET-1, ET(A), and ET(B) receptors in GCA. DESIGN Experimental, retrospective immunohistochemical study of temporal arteries using archival formalin-fixed, paraffin-embedded tissue. PARTICIPANTS The study included 10 patients with GCA and 10 control patients with clinically suspected GCA but diagnosed not to have GCA. METHODS Immunohistochemistry, with anti ET-1, anti-ET(A), and anti-ET(B) antibodies, was performed on formalin-fixed and paraffin-embedded temporal arteries. MAIN OUTCOME MEASURES Endothelin-1, ET(A), and ET(B) receptor immunostaining intensities were quantified. RESULTS Temporal arteries from the patients with GCA showed the typical histologic features, including intimal thickening, disruption or loss of the elastic lamina, and inflammatory infiltrates of lymphocytes, macrophages, and multinucleated giant cells. These features were associated with increased ET-1 and ET(B) receptor immunoreactivity in the medial layer of the temporal arteries and endothelial cells in patients with GCA compared with the controls. The increased ET-1 and ET(B) receptor immunoreactivity occurred in vascular smooth muscle cells (SMCs) and multinucleated giant cells. The ET-1 and ET(B) receptor immunoreactivity correlated with the degree of systemic inflammation. No changes were observed in ET(A) receptor expression in SMCs or endothelial cells compared with controls. CONCLUSIONS The results suggest a role for ET-1 and ET(B) receptors in GCA. Inhibiting the ET system may provide a corticosteroid-sparing alternative in the treatment of GCA.

Increased angiotensin II type 1 receptor expression in temporal arteries from patients with giant cell arteritis.

PURPOSE Currently, giant cell arteritis (GCA) is primarily treated with corticosteroids or immunomodulating agents, but there is interest in identifying other noncorticosteroid alternatives. Similarities exist in the injury pathways between GCA and atherosclerosis. Angiotensin II is a vasoactive peptide involved in vessel inflammation during atherosclerosis, and angiotensin II receptor inhibitors are effective in preventing atherosclerosis. The present study was performed to elucidate the role of angiotensin type 1 (AT(1)) and type 2 (AT(2)) receptors in GCA. DESIGN Experimental retrospective immunohistochemical study of temporal arteries using archival formalin-fixed, paraffin-embedded tissue. PARTICIPANTS Ten patients with GCA and 10 control patients, who were clinically suspected of having GCA but were diagnosed as not having GCA, were included. METHODS Immunohistochemistry, using anti-AT(1) and anti-AT(2) antibodies, was performed on formalin-fixed and paraffin-embedded temporal arteries. MAIN OUTCOME MEASURES AT(1) and AT(2) receptor immunostaining intensity was quantified. RESULTS Hematoxylin-eosin-stained sections of temporal arteries from patients with GCA showed intimal hyperplasia, internal elastic lamina degeneration, and band-shaped infiltrates of inflammatory cells, including lymphocytes, histocytes, and multinucleated giant cells. AT(1) receptor staining was primarily observed in the medial layer of the temporal arteries and was higher in the patients with GCA than in the control patients. This was a result of increased AT(1) receptor immunostaining of both vascular smooth muscle cells and infiltrating inflammatory cells. Only faint immunostaining was seen for AT(2) receptors, primarily in the endothelial cells, and to a lesser extent on the smooth muscle cells. Immunostaining with antibodies for the AT(2) receptor was similar in the patients with GCA and in controls. CONCLUSIONS These results suggest that AT(1) receptors play a role in the development of GCA. Inhibition of the angiotensin system may thus provide a noncorticosteroid alternative for the treatment of GCA. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Microcirculation changes during liver resection — A clinical study

BACKGROUND In this study we aimed to evaluate effects of liver resection on hepatic microcirculation. In addition we wanted to study if histological liver damage could be detected intra-operatively. PATIENTS AND METHODS 40 patients undergoing hepatic resection were included and grouped according to if they were operated with a major or minor resection. Hepatic microcirculation measurements were made intra-operatively before and after liver resection with sidestream dark-field (SDF) imaging. Red blood cell velocity (RBCV), sinusoidal diameter and functional sinusoidal density were determined. RESULTS After hepatic resection RBCV increased in both the minor and major groups (44 μm/s, P=0.016 and 121 μm/s, P=0.002). RBCV in patients with histological damages was 225 (148-464) μm/s vs. 161 (118-329) μm/s in patients with no damage (P=0.016). CONCLUSION A hepatic resection leads to an increase of sinusoidal RBCV. SDF imaging could potentially be used to intraoperatively identify histological damages.

Frequent low-level mutations of Protein Kinase D2 in angiolipoma

Tumours displaying differentiation towards normal fat constitute the most common subgroup of soft tissue neoplasms. A series of such tumours was investigated by whole‐exome sequencing followed by targeted ultra‐deep sequencing. Eighty per cent of angiolipomas, but not any other tumour type, displayed mutations in the protein kinase D2 (PRKD2) gene, typically in the part encoding the catalytic domain. The absence of other aberrations at the chromosome or RNA level suggests that PRKD2 mutations are critical for angiolipoma development. Consistently, the mutated PRKD2 alleles were present at low (3–15%) frequencies, indicating that only a subset of the tumour cells is affected. Indeed, by sequencing mature fat cells and other cells separately, the former typically showed the highest mutation frequencies. Thus, we hypothesize that altered PRKD2 signalling in the adipocytic cells drives tumourigenesis and, in agreement with its pivotal role in angiogenesis, induces the vessel formation that is characteristic for angiolipoma. Copyright

Reduced expression of angiotensin II and angiotensin receptor type 1 and type 2 in resistance arteries from nasal lesions in granulomatosis with polyangiitis (Wegener's granulomatosis).

Objectives: Angiotensin II (ANGII) is involved in vessel inflammation and is important in the development of cardiovascular disorders such as atherosclerosis. During active disease, patients with granulomatosis with polyangiitis (GPA; Wegener’s granulomatosis) have accelerated atherosclerosis and ANGII inhibitors are recommended to these patients to reduce atherosclerosis. We assessed the hypothesis that the expression of ANGII and its receptors in arteries in granulomatous lesions change in GPA. Methods: ANGII and angiotensin receptors were quantified in vessels from granulomatous lesions from patients with GPA using immunohistochemistry. Anti- ANGI type 1 (AT1) and type 2 (AT2) antibodies were applied on formalin-fixed and paraffin-embedded biopsies from nasal mucous membranes from eight patients with GPA and eight controls. Results: ANGII expression was localized to the endothelial cells (ECs) in arteries and sparsely to vascular smooth muscle cells (VSMCs) in nasal biopsies. AT1 receptor (AT1R) staining was intense and located in the VSMCs in the medial layer of the control arteries. AT2 receptor (AT2R) immunostaining was faint and was located only in the ECs. Patients with GPA showed marked down-regulation of positively immunostained ECs for ANGII or AT2R, and a reduced number of AT1R in VSMCs. ANGII, AT1R, and AT2R staining was persistent on infiltrating leucocytes. Conclusions: These results suggest down-regulation of the angiotensin system in arteries in granulomatous nasal lesions in GPA. Inhibition of the angiotensin system may prove less efficient in inhibiting the vascular inflammation process in GPA.

Different patterns of clonal evolution among different sarcoma subtypes followed for up to 25 years

To compare clonal evolution in tumors arising through different mechanisms, we selected three types of sarcoma—amplicon-driven well-differentiated liposarcoma (WDLS), gene fusion-driven myxoid liposarcoma (MLS), and sarcomas with complex genomes (CXS)—and assessed the dynamics of chromosome and nucleotide level mutations by cytogenetics, SNP array analysis and whole-exome sequencing. Here we show that the extensive single-cell variation in WDLS has minor impact on clonal key amplicons in chromosome 12. In addition, only a few of the single nucleotide variants in WDLS were present in more than one lesion, suggesting that such mutations are of little significance in tumor development. MLS displays few mutations other than the FUS-DDIT3 fusion, and the primary tumor is genetically sometimes much more complex than its relapses, whereas CXS in general shows a gradual increase of both nucleotide- and chromosome–level mutations, similar to what has been described in carcinomas.Hofvander and colleagues compare the patterns of clonal evolution in different pathogenetic subgroups of sarcoma. They show that sarcomas driven by gene fusion or amplification display few additional changes over time, whereas sarcomas with complex karyotypes show a gradual increase of nucleotide- and chromosome-level mutations.

Loss of the tumor suppressor gene AIP mediates the browning of human brown fat tumors

Human brown fat tumours (hibernomas) show concomitant loss of the tumour suppressor genes MEN1 and AIP. We hypothesized that the brown fat phenotype is attributable to these mutations. Accordingly, in this study, we demonstrate that silencing of AIP in human brown preadipocytic and white fat cell lines results in the induction of the brown fat marker UCP1. In human adipocytic tumours, loss of MEN1 was found both in white (one of 51 lipomas) and in brown fat tumours. In contrast, concurrent loss of AIP was always accompanied by a brown fat morphology. We conclude that this white‐to‐brown phenotype switch in brown fat tumours is mediated by the loss of AIP. Copyright