Afschin Soleiman

Angiosarcomas Express Mixed Endothelial Phenotypes of Blood and Lymphatic Capillaries: Podoplanin as a Specific Marker for Lymphatic Endothelium

Angiosarcomas apparently derive from blood vessel endothelial cells; however, occasionally their histological features suggest mixed origin from blood and lymphatic endothelia. In the absence of specific positive markers for lymphatic endothelia the precise distinction between these components has not been possible. Here we provide evidence by light and electron microscopic immunohistochemistry that podoplanin, a approximately 38-kd membrane glycoprotein of podocytes, is specifically expressed in the endothelium of lymphatic capillaries, but not in the blood vasculature. In normal skin and kidney, podoplanin colocalized with vascular endothelial growth factor receptor-3, the only other lymphatic marker presently available. Complementary immunostaining of blood vessels was obtained with established endothelial markers (CD31, CD34, factor VIII-related antigen, and Ulex europaeus I lectin) as well as podocalyxin, another podocytic protein that is also localized in endothelia of blood vessels. Podoplanin specifically immunolabeled endothelia of benign tumorous lesions of undisputed lymphatic origin (lymphangiomas, hygromas) and was detected there as a 38-kd protein by immunoblotting. As paradigms of malignant vascular tumors, poorly differentiated (G3) common angiosarcomas (n = 8), epitheloid angiosarcomas (n = 3), and intestinal Kaposis sarcomas (n = 5) were examined for their podoplanin content in relation to conventional endothelial markers. The relative number of tumor cells expressing podoplanin was estimated and, although the number of cases in this preliminary study was limited to 16, an apparent spectrum of podoplanin expression emerged that can be divided into a low-expression group in which 0-10% of tumor cells contained podoplanin, a moderate-expression group with 30-60% and a high-expression group with 70-100%. Ten of eleven angiosarcomas and all Kaposis sarcomas showed mixed expression of both lymphatic and blood vascular endothelial phenotypes. By double labeling, most podoplanin-positive tumor cells coexpressed endothelial markers of blood vessels, whereas few tumor cells were positive for individual markers only. From these results we conclude that (1) podoplanin is a selective marker of lymphatic endothelium; (2) G3 angiosarcomas display a quantitative spectrum of podoplanin-expressing tumor cells; (3) in most angiosarcomas, a varying subset of tumor cells coexpresses podoplanin and endothelial markers of blood vessels; and (4) all endothelial cells of Kaposis sarcomas expressed the lymphatic marker podoplanin.

Lymphatic Neoangiogenesis in Human Kidney Transplants Is Associated with Immunologically Active Lymphocytic Infiltrates

Renal transplant rejection is caused by a lymphocyte-rich inflammatory infiltrate that attacks cortical tubules and endothelial cells. Immunosuppressive therapy reduces the number of infiltrating cells; however, their exit routes are not known. Here a >50-fold increase of lymphatic vessel density over normal kidneys in grafts with nodular mononuclear infiltrates is demonstrated by immunohistochemistry on human renal transplant biopsies using antibodies to the lymphatic endothelial marker protein podoplanin. Nodular infiltrates are constantly associated with newly formed, Ki-67-expressing lymphatic vessels and contain the entire repertoire of T and B lymphocytes to provide specific cellular and humoral alloantigenic immune responses, including Ki-67(+) CD4(+) and CD8(+) T lymphocytes, S100(+) dendritic cells, and Ki-67(+)CD20(+) B lymphocytes and lambda- and kappa-chain-expressing plasmacytoid cells. Numerous chemokine receptor CCR7(+) cells within the nodular infiltrates seemed to be attracted by secondary lymphatic chemokine (SLC/CCL21) that is produced and released by lymphatic endothelial cells in a complex with podoplanin. From these results, it is speculated that lymphatic neoangiogenesis not only contributes to the export of the rejection infiltrate but also is involved in the maintenance of a potentially detrimental alloreactive immune response in renal transplants and provides a novel therapeutic target.

Tumour necrosis factor blockade increases lymphangiogenesis in murine and human arthritic joints

OBJECTIVE To investigate the presence and regulation of lymphatic vessels in inflamed joints of mice with experimental arthritis as well as patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA). METHODS Lymphatic vessels and blood vessels were assessed in synovial tissue of human tumour necrosis factor transgenic (TNFtg) mice and synovial biopsies from patients with RA and SpA by immunohistochemistry for podoplanin and CD31, respectively. Assessments were performed before and after TNF blockade in all biopsies. RESULTS Lymphatic vessels were abundantly present in the synovial tissue of hTNFtg mice as well as patients with RA and SpA. The number of lymphatic vessels was positively related to the severity of synovial inflammation. Treatment with infliximab led to an increase in the formation of lymphatic vessels in murine and human inflammatory tissue. CONCLUSIONS This study shows that TNF blockade promotes the proliferation of lymphatic vessels in the inflamed synovium of RA and SpA. This finding leads to the assumption that promotion of lymphangiogenesis may play an important part in efflux of cells and fluid out of the inflamed tissue.

Epidermal loss of JunB leads to a SLE phenotype due to hyper IL-6 signaling

Systemic lupus erythematosus (SLE) is a complex autoimmune disease affecting various tissues. Involvement of B and T cells as well as increased cytokine levels have been associated with disease manifestation. Recently, we demonstrated that mice with epidermal loss of JunB (JunBΔep) develop a myeloproliferative syndrome (MPS) due to high levels of G-CSF which are secreted by JunB-deficient keratinocytes. In addition, we show that JunBΔep mice develop a SLE phenotype linked to increased epidermal interleukin 6 (IL-6) secretion. Intercrosses with IL-6-deficient mice could rescue the SLE phenotype. Furthermore, we show that JunB binds to the IL-6 promoter and transcriptionally suppresses IL-6. Facial skin biopsies of human SLE patients similarly revealed low JunB protein expression and high IL-6, activated Stat3, Socs-1, and Socs-3 levels within lupus lesions. Thus, keratinocyte-induced IL-6 secretion can cause SLE and systemic autoimmunity. Our results support trials to use α-IL-6 receptor antibody therapy for treatment of SLE.

Nesidioblastosis in adults: a challenging cause of organic hyperinsulinism.

Background Nesidioblastosis in adults has been reintroduced into the differential diagnosis of organic hyperinsulinism by the description of ‘noninsulinoma pancreatogenous hypoglycaemia syndrome (NIPHS)’.

miRNA Profiling Discriminates Types of Rejection and Injury in Human Renal Allografts

Background Increasing evidence accumulates on the central involvement of microRNAs (miRNAs) in disease pathophysiology. We identified distinctly deregulated miRNAs in human renal allograft biopsies from patients undergoing acute cellular rejection, antibody-mediated rejection (ABMR), and delayed graft function (DGF). Methods Sixty-five posttransplantation kidney biopsy samples covering 41 cases with acute rejection (15 vascular rejection, 15 interstitial rejection, and 11 ABMR), 14 DGF cases, and 10 protocol biopsies serving as controls were analyzed using the Affymetrix GeneChip miRNA Array. Differentially regulated miRNAs were identified by Student’s t test and Bonferroni correction. Target genes for the set of miRNAs were retrieved from miRTarBase (experimentally verified targets) as well as by applying the target prediction routines DIANAmT, miRanda, and Targetscan. Results Patients with acute cellular rejection, ABMR, and DGF discriminate from the control group (protocol biopsies) in unsupervised clustering of miRNA profiles, clearly identifying deregulated miRNAs in rejection and DGF. Angiogenesis, apoptosis, and transforming growth factor-&bgr; signaling were identified as relevant pathways in ischemic response following an integrative analysis of miRNA targets and mRNA expression profiles. Inflammation by chemokine and cytokine signaling, T-cell activation, and B-cell activation were identified as relevant in acute rejection accordingly. Conclusion These data suggest that distinct miRNA signatures playing a role in specific biological pathways discriminate acute cellular and humoral rejection and DGF. This finding serves as valuable tool for a rational selection of diagnostic, prognostic, and potentially therapeutic molecular targets of posttransplantation events.

Irradiated cultured apoptotic peripheral blood mononuclear cells regenerate infarcted myocardium

Background  Acute myocardial infarction (AMI) is followed by post AMI cardiac remodelling, often leading to congestive heart failure. Homing of c‐kit+ endothelial progenitor cells (EPC) has been thought to be the optimal source for regenerating infarcted myocardium.

Gene-expression profiles and age of donor kidney biopsies obtained before transplantation distinguish medium term graft function.

Background. Donor factors such as age profoundly influence long-term graft function after cadaveric renal transplantation, but the molecular signature of these aspects in the allograft remains unknown. Methods. We analyzed the genome-wide gene expression signature of donor kidney biopsies of different ages obtained before transplantation. Subsequent analysis compared expression profiles from allografts with excellent function versus impaired function at 1 yr after engraftment. Differential expression profiles were analyzed on the level of molecular function and biologic role, as well as by analysis of co-regulation through transcription factors, regulatory networks, and protein-protein interaction data utilizing extended bioinformatics. Results. The 15 subjects with excellent transplant function defined as calculated GFR≥45 mL/min/1.73 m2 at 1 yr exhibited a distinctly different gene expression profile than the matched 16 subjects with impaired function defined as calculated GFR<45 mL/min/1.73 m2. Donor kidneys from recipients with impaired allograft function showed activation of genes mainly belonging to the functional classes of immunity, signal transduction, and oxidative stress response. Two-thirds of these genes exhibited at least one protein interacting partner, suggesting choreographed intracellular events differentiating the two recipient groups. However, donor age may have confounded some of the associations found between gene profiles and graft function. Conclusion. In summary, a distinctive gene expression profile in the donor kidney at transplantation together with donor age predicts medium term allograft function in recipients of cadaveric allografts.

Histogenomics: association of gene expression patterns with histological parameters in kidney biopsies.

Background. Several studies investigated the association of histologic scores of donor kidney biopsies obtained before engraftment with posttransplant outcomes. Discrimination and goodness of fit of these scores, however, is low. Methods. Thus, we sought to identify and elucidate the performance of molecular rather than histologic markers for this purpose using whole genome gene expression microarray experiments. Results. We identified 80 unique differentially regulated genes in 82 samples, showing no histologic damage versus those with histologic damage, based on the Chronic Allograft Damage Index (CADI) and acute tubular injury. Main biological categories enriched with up-regulated genes in damaged tissue were “immunity and defense,” “cell communication,” or “apoptosis.” Interestingly, genes involved in cell structure, cell adhesion, and protein trafficking were specific for tubular atrophy. Histology (CADI score) explained only 14% of the variability of 1 year creatinine (adjusted R2 for panel-reactive antibodies, biopsy confirmed acute rejection, and sum of human leukocyte antigen mismatches) whereas a combination of three biomarkers without clinical covariables explained 28%. The three molecular markers are the NLR family, pyrin domain containing 2 (NLRP2), immunoglobulin J polypeptide, and the regulator of G-protein signaling 5. Conclusion. In summary, we identified biomarkers in transplant kidney biopsies, which are predictive for medium-term allograft function.

Refractory Wegener’s granulomatosis responds to tumor necrosis factor blockade

ZusammenfassungMorbus Wegener ist eine vor allem kleinste Gefäße betreffende nekrotisierende Vaskulitis, die zu einer erheblichen Funktionsbe einträchtigung der beteiligten Organsysteme führt und hauptsächlich in den Nieren und im Respirationstrakt manifest wird. Die übliche Therapie basiert auf längerfristiger Immunsuppression bestehend aus einer Kombination von Kortikosteroiden. Cyclophosphamid, Azathioprin oder Methotraxat. Tödliche Verläufe sind oft Folge von Rezidiven oder mangelndem Ansprechen auf diese Therapie. Wie bei vielen chronisch entzündlichen Erkrankungen beeinflusst der Tumornekrosefaktor (TNF) wesentlich das Voranschreiten der Erkrankung. Wir berichten über einen Patienten mit massiver orbitaler Morbus Wegener Manifestation, der unter maximaler Cyclophosphamid- und Kortikosteroidtherapie ein akutes Nierenversagen entwickelte. Um eine weitere Progression zu verhindern, wurde ihm über sechs Monate hinweg der TNF-Antikörper Infliximab® in einer Dosis von 3 mg/kg Körpergewicht sechs mal verabreicht. Zusätzlich wurde in dieser Zeit die Therapie mit Kortikosteroiden und Cyclophosphamid fortgesetzt, wobei letzteres nach drei Monaten durch Azathioprin ersetzt wurde. Bere its die erste Infliximab®-Infusion führte zu einer Verbesserung der Nierenfunktion, eine Entwicklung, welche die gesamte Therapie hindurch anhielt. Die MDRD-GFR (Modification of Diet in Renal Disease — Glomerular Filtration Rate) stieg von 15,3 ml/min/1,73 m2 vor der ersten auf 55,5 ml/min/1,73 m2 nach der letzten Infusion. Die Serumkreatininkonzentration und die Proteinurie verminderten sich ebenso wie die cANCA Titer. Ohne Auftreten von Nebenwirkungen wurde duch die TNF-Blockade eine klinische Remission erzielt. Eine erneut auftretende Entzündung der Orbita wurde durch eine erhöhte Dosis Azathioprin erfolgreich behandelt. Bei diesem Fall eines therapierefraktären Morbus Wegener stellte der Einsatz des monklonalen TNF-Antikörpers Infliximab® ein wirksames Mittel zur Induktion einer klinischen Remission mit Wiederherstellung der Nierenfunktion dar.SummaryWegener’s granulomatosis is a systemic necrotising vasculitis of small vessels that leads to severe impairment of affected organ systems. Conventional treatment is based on immunosuppression with a combination of steroids, cyclophosphamide, azathioprine or methotrexate over a prolonged time course. Early recurrence or disease refractory to therapy often results in a fatal outcome. As in other inflammatory disorders, tumor necrosis factor (TNF) plays an early and crucial role in progression of disease activity. We report on a patient with severe orbital Wegener’s granulomatosis who developed acute renal failure despite intense conventional immunosuppression with cyclophosphamide and steroids. To stop vasculitic activity, by disrupting the autoimmune inflammatory cascade, a TNF-blocking antibody (Infliximabŗ) was administered six times in a six-month period at 3 mg/kg body weight. Conventional immunosuppressive therapy with steroids and cyclophosphamide was continued, the latter being changed to azathioprine after three months. The first infusion of TNF antibody induced improvement of renal function, which continued throughout the course of therapy. The modification of diet in renal disease-glomerular filtration rate (MDRD-GFR) increased from 15.3 ml/min/1.73m2 before the start of TNF-blockade to 55.5ml/min/1.73m2 after six months of therapy. Serum creatinine levels, proteinuria and cANCA titer decreased concomitantly. Clinical remission of Wegener’s granulomatosis was induced without any major adverse events. A slight flare of orbital inflammation was successfully treated with an increased dose of azathioprine. Thus, in this case of refractory Wegener’s granulomatosis TNF-blockade by monoclonal chimeric TNF-antibody (Infliximabŗ) served as an effective tool to rescue kidney function and induce clinical remission.