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Ischemia-reperfusion injury is a major cause of acute kidney injury. Many cytokines are involved in the pathogenesis of renal ischemia-reperfusion injury. IL24 is a member of the IL10 family and has gained importance because of its apoptosis-inducing effects in tumor disease besides its immunoregulative function. Littles is known about the role of IL24 in kidney disease. Using a mouse model, we found that IL24 is upregulated in the kidney after renal ischemia-reperfusion injury and that tubular epithelial cells and infiltrating inflammatory cells are the source of IL24. Mice lacking IL24 are protected from renal injury and inflammation. Cell culture studies showed that IL24 induces apoptosis in renal tubular epithelial cells, which is accompanied by an increased endoplasmatic reticulum stress response. Moreover, IL24 induces robust expression of endogenous IL24 in tubular cells, fostering ER-stress and apoptosis. In kidney transplant recipients with delayed graft function and patients at high risk to develop acute kidney injury after cardiac surgery IL24 is upregulated in the kidney and serum. Taken together, IL24 can serve as a biomarker, plays an important mechanistic role involving both extracellular and intracellular targets, and is a promising therapeutic target in patients at risk of or with ischemia-induced acute kidney injury.

Dendritic cells (DCs) are heterogeneous immune regulators involved in autoimmune diseases. Epigenomic mechanisms orchestrating DC development and DC subset diversification remain insufficiently understood but could be important to modulate DC fate for clinical purposes. By combining whole-genome methylation assessment with the analysis of mice expressing reduced DNA methyltransferase 1 levels, we show that distinct DNA methylation levels and patterns are required for the development of plasmacytoid DC and conventional DC subsets. We provide clonal in vivo evidence for DC lineage establishment at the stem cell level, and we show that a high DNA methylation threshold level is essential for Flt3-dependent survival of DC precursors. Importantly, reducing methylation predominantly depletes plasmacytoid DC and alleviates systemic lupus erythematosus in an autoimmunity mouse model. This study shows how DNA methylation regulates the production of DC subsets and provides a potential rationale for targeting autoimmune disease using hypomethylating agents.

BACKGROUND In transplant medicine, clinical decision making largely relies on histology of biopsy specimens. However, histology suffers from low specificity, sensitivity, and reproducibility, leading to suboptimal stratification of patients. We developed a histology-independent immune framework of kidney graft homeostasis and rejection. METHODS We applied tailored RNA deconvolution for leukocyte enumeration and coregulated gene network analysis to published bulk human kidney transplant RNA transcriptomes as input for unsupervised, high-dimensional phenotype clustering. We used framework-based graft survival analysis to identify a biomarker that was subsequently characterized in independent transplant biopsy specimens. RESULTS We found seven immune phenotypes that confirm known rejection types and uncovered novel signatures. The molecular phenotypes allow for improved graft survival analysis compared with histology, and identify a high-risk group in nonrejecting transplants. Two fibrosis-related phenotypes with distinct immune features emerged with reduced graft survival. We identified lysyl oxidase-like 2 (LOXL2)-expressing peritubular CD68+ macrophages as a framework-derived biomarker of impaired allograft function. These cells precede graft fibrosis, as demonstrated in longitudinal biopsy specimens, and may be clinically useful as a biomarker for early fibrogenesis. CONCLUSIONS This study provides a comprehensive, data-driven atlas of human kidney transplant phenotypes and demonstrates its utility to identify novel clinical biomarkers.

Neutrophil adhesion and extravasation into tissue at sites of injury or infection depend on binding of the integrin lymphocyte function–associated antigen 1 (LFA-1) to ICAM-1 expressed on activated endothelial cells. The activation-dependent conformational change of LFA-1 to the high-affinity conformation (H+) requires kindlin-3 binding to the β2-integrin cytoplasmic domain. Here we show that genetic deletion of the known kindlin interactor integrin-linked kinase (ILK) impaired neutrophil adhesion and extravasation in the cremaster muscle and in a clinically relevant model of renal ischemia reperfusion injury. Using in vitro microfluidic adhesion chambers and conformation-specific antibodies, we show that knockdown of ILK in HL-60 cells reduced the conformational change of β2-integrins to the H+ conformation. Mechanistically, we found that ILK was required for protein kinase C (PKC) membrane targeting and chemokine-induced upregulation of its kinase activity. Moreover, PKC-α deficiency also resulted in impaired leukocyte adhesion in bone marrow chimeric mice. Mass spectrometric and western blot analyses revealed stimulation- and ILK-dependent phosphorylation of kindlin-3 upon activation. In summary, our data indicate an important role of ILK in kindlin-3–dependent conformational activation of LFA-1.

Cisplatin (CDDP) is one of the most important chemotherapeutic drugs in modern oncology. However, its use is limited by severe toxicities, which impair life quality after cancer. Here, we investigated the role of organic cation transporters (OCT) in mediating toxicities associated with chronic (twice the week for 4weeks) low-dose (4mg/kg body weight) CDDP treatment (resembling therapeutic protocols in patients) of wild-type (WT) mice and mice with OCT genetic deletion (OCT1/2−/−). Functional and molecular analysis showed that OCT1/2−/− mice are partially protected from CDDP-induced nephrotoxicity and peripheral neurotoxicity, whereas ototoxicity was not detectable. Surprisingly, proteomic analysis of the kidneys demonstrated that genetic deletion of OCT1/2 itself was associated with significant changes in expression of proinflammatory and profibrotic proteins which are part of an OCT-associated protein network. This signature directly regulated by OCT consisted of three classes of proteins, viz., profibrotic proteins, proinflammatory proteins, and nutrient sensing molecules. Consistent with functional protection, CDDP-induced proteome changes were more severe in WT mice than in OCT1/2−/− mice. Laser ablation-inductively coupled plasma-mass spectrometry analysis demonstrated that the presence of OCT was not associated with higher renal platinum concentrations. Taken together, these results redefine the role of OCT from passive membrane transporters to active modulators of cell signaling in the kidney.

Renal ischemia reperfusion injury (IRI) adversely affects clinical outcomes following kidney transplantation. Understanding the cellular mechanisms and the changes in gene/protein expression following IRI may help to improve these outcomes. Serum soluble fms-like tyrosine kinase 1 (sFlt-1), a circulating antiangiogenic protein, is increased in the first week following kidney transplantation. We evaluated the casual relationship of elevated sFlt-1 levels with renal microvascular dysfunction following IRI in a longitudinal study of 93 kidney transplant recipients and in several animal models. Transplant recipients with higher sFlt-1 levels had higher odds of delayed graft function, graft rejection, impaired graft function, and death. In a subgroup of 25 participants who underwent kidney biopsy within 4 months of kidney transplantation, peritubular capillary area was lower in those with elevated serum sFtl-1 levels. The administration of recombinant sFlt-1 into rodents resulted in significant structural and functional changes of the renal microvasculature, including reduced peritubular capillary density and intracapillary blood volume, and lead to increased expression of inflammatory genes and increased fibrosis. In a murine model of IRI, the kidney was a site of sFlt-1 production, and systemic neutralization of sFlt-1 preserved peritubular capillary density and alleviated renal fibrosis. Our data indicate that high sFlt-1 levels after IRI play an important role in the pathogenesis of microvascular dysfunction, thereby contributing to adverse clinical outcomes following kidney transplantation.

Minimal extrathyroidal extension (mETE) of papillary thyroid microcarcinoma (PTMC) is no longer considered in the new eighth edition of the staging manual of the American Joint Committee on Cancer and the International Union Against Cancer. Therefore, PTMC with mETE previously staged as pT3 will now be staged as pT1a and most likely not receive adjuvant radioiodine therapy. However, it remains unclear whether mETE is associated with higher aggressiveness in PTMC. Therefore, the aim of this study was to investigate whether mETE is associated with a higher risk of lymph node metastases (LNMs) or distant metastases. Methods: In total, 721 patients with PTMC presenting at our department for postoperative counseling from May 1983 to August 2012 were included in this retrospective analysis (median follow-up time, 9.30 y). The impact of mETE on the presence of LNMs at thyroidectomy and relapse through LNMs and distant metastases was assessed by logistic regression and Fine–Gray model analyses. Results: mETE was present in 10.7% (n = 77) of patients and was an independent risk factor for LNMs at thyroidectomy, with an adjusted odds ratio of 4.33 (95% CI, 2.02–9.60; P < 0.001) in multivariable analysis. Patients with mETE had significantly more relapses through LNMs (over 5 y: 13.1% vs. 1.25%; P < 0.001) and distant metastases (over 5 y: 7.8% vs. 1.1%; P < 0.001) than did patients without mETE. mETE was an independent risk factor for relapse through LNMs and distant metastases in multivariable analysis (hazard ratio of 7.78 and 95% CI of 2.87–21.16 for LNMs [P < 0.001]; hazard ratio of 4.09 and 95% CI of 1.25–13.36 for distant metastases [P = 0.020]). Conclusion: mETE is a statistically significant and independent risk factor for relapse through LNMs and distant metastases in PTMC. Therefore, future studies should evaluate whether patients with mETE and PTMC might benefit from intensified surveillance and therapy.

Minimal extrathyroidal extension (mETE) of papillary thyroid microcarcinoma (PTMC) is no longer considered in the new eighth edition of the staging manual of the American Joint Committee on Cancer and the International Union Against Cancer. Therefore, PTMC with mETE previously staged as pT3 will now be staged as pT1a and most likely not receive adjuvant radioiodine therapy. However, it remains unclear whether mETE is associated with higher aggressiveness in PTMC. Therefore, the aim of this study was to investigate whether mETE is associated with a higher risk of lymph node metastases (LNMs) or distant metastases. Methods: In total, 721 patients with PTMC presenting at our department for postoperative counseling from May 1983 to August 2012 were included in this retrospective analysis (median follow-up time, 9.30 y). The impact of mETE on the presence of LNMs at thyroidectomy and relapse through LNMs and distant metastases was assessed by logistic regression and Fine-Gray model analyses. Results: mETE was present in 10.7% (n = 77) of patients and was an independent risk factor for LNMs at thyroidectomy, with an adjusted odds ratio of 4.33 (95% CI, 2.02-9.60; P < 0.001) in multivariable analysis. Patients with mETE had significantly more relapses through LNMs (over 5 y: 13.1% vs. 1.25%; P < 0.001) and distant metastases (over 5 y: 7.8% vs. 1.1%; P < 0.001) than did patients without mETE. mETE was an independent risk factor for relapse through LNMs and distant metastases in multivariable analysis (hazard ratio of 7.78 and 95% CI of 2.87-21.16 for LNMs [P < 0.001]; hazard ratio of 4.09 and 95% CI of 1.25-13.36 for distant metastases [P = 0.020]). Conclusion: mETE is a statistically significant and independent risk factor for relapse through LNMs and distant metastases in PTMC. Therefore, future studies should evaluate whether patients with mETE and PTMC might benefit from intensified surveillance and therapy.

Aim: The present study aims to evaluate protective effects of a novel histidine–tryptophan–ketoglutarate solution (HTK-N) and to investigate positive impacts of an additional luminal preservation route in cold storage-induced injury on rat small bowels. Methods: Male Lewis rats were utilized as donors of small bowel grafts. Vascular or vascular plus luminal preservation were conducted with HTK or HTK-N and grafts were stored at 4°C for 8 h followed by ex vivo warm oxygenated reperfusion with Krebs–Henseleit buffer for 30 min. Afterwards, intestinal tissue and portal vein effluent samples were collected for evaluation of morphological alterations, mucosal permeability and graft vitality. Results: The novel HTK-N decreased ultrastructural alterations but otherwise presented limited effect on protecting small bowel from ischemia–reperfusion injury in vascular route. However, the additional luminal preservation led to positive impacts on the integrity of intestinal mucosa and vitality of goblet cells. In addition, vascular plus luminal preservation route with HTK significantly protected the intestinal tissue from edema. Conclusion: HTK-N protected the intestinal mucosal structure and graft vitality as a luminal preservation solution. Additional luminal preservation route in cold storage was shown to be promising.

Intracellular trafficking processes play a key role for the establishment and maintenance of membrane surfaces in renal epithelia. Therefore, dysfunctions of these trafficking processes could be key events and important determinants in the onset and progression of diseases. The presence of cellular vacuoles—observed in many histologic analyses of renal diseases—is a macroscopic hint for disturbed intracellular trafficking processes. However, how vacuoles develop and which intracellular pathways are directly affected remain largely unknown. Previous studies showed that in some cases, vacuolization is linked to malfunction of the Vac14 complex. This complex, including the scaffold protein Vac14, the lipid kinase PIKfyve, and its counteracting lipid phosphatase Fig4, regulates intracellular phosphatidylinositol phosphate levels, which in turn, control the maturation of early-into-late endosomes, as well as the processing of autophagosomes into autophagolysosomes. Here, we analyzed the role of Vac14 in mice and observed that the nephron-specific knockin of the PIKfyve-binding-deficient Vac14L156Rmutant led to albuminuria, accompanied by mesangial expansion, increased glomerular size, and an elevated expression of several kidney injury markers. Overexpression of this Vac14 variant in podocytes did not reveal a strong in vivo phenotype, indicating that Vac14-dependent trafficking processes are more important for tubular than for glomerular processes in the kidney. In vitro overexpression of Vac14L156Rin Madin-Darby canine kidney cells had no impact on apico-basal polarity defects but resulted in a faster reassembly of junctional structures after Ca2+depletion and delayed endo- and transcytosis rates. Taken together, our data suggest that increased albuminuria of Vac14L156R-overexpressing mice is a consequence of a lowered endo- and transcytosis of albumin in renal tubules.

We investigated the prognostic value of PD-1 and PD-L1 expression in patients with high grade upper tract urothelial carcinoma.Tissue microarrays of 423 patients treated with extirpative surgery for high grade upper tract urothelial carcinoma from the International Upper Tract Urothelial Carcinoma collaboration were stained for PD-1 and PD-L1 using antibodies, including Cell Marque™ NAT105 diluted 1:250 and prediluted E1L3N® via immunohistochemistry. A 1% or greater staining rate of tumor infiltrating lymphocytes (PD-1) and tumor cells (PD-L1) was considered positive. Univariate and multivariate analyses were performed to assess independent prognosticators of survival outcomes.Median patient age was 70.0 years and median followup was 37.0 months. PD-1 and PD-L1 were positive in 37.2% and 26.2% of patients, respectively. PD-1 positivity was significantly associated with adverse pathological characteristics while PD-L1 positivity was associated with favorable pT stage. On univariate analysis PD-1 expression was associated with worse recurrence-free, cancer specific and overall survival. On multivariate analysis PD-1 expression was an independent prognosticator of cancer specific survival (HR 1.7, 95% CI 1.03-2.66, p = 0.039) and overall survival (HR 1.5, 95% CI 1.05-2.24, p = 0.029) but not recurrence-free survival (HR 1.4, 95% CI 0.9-2.16, p = 0.139). On univariate analysis PD-L1 expression was not significantly associated with survival outcomes. However, on multivariate analysis in patients with organ confined disease (pT2 or less, pN0/x and cM0), PD-L1 positivity was an independent prognosticator of recurrence-free survival (HR 0.2, 95% CI 0.06-0.98, p = 0.046) and overall survival (HR 0.3, 95% CI 0.11-0.63, p = 0.003).PD-1 positivity of tumor-infiltrating lymphocytes was associated with adverse pathological criteria and independent prognostication of worse survival outcomes. PD-L1 positivity of tumor cells was an independent prognosticator of favorable survival outcomes in cases of organ confined disease.

Fast tacrolimus metabolism is linked to inferior outcomes such as rejection and lower renal function after kidney transplantation. Renal calcineurin-inhibitor toxicity is a common adverse effect of tacrolimus therapy. The present contribution hypothesized that tacrolimus-induced nephrotoxicity is related to a low concentration/dose (C/D) ratio. We analyzed renal tubular epithelial cell cultures and 55 consecutive kidney transplant biopsy samples with tacrolimus-induced toxicity, the C/D ratio, C0, C2, and C4 Tac levels, pulse wave velocity analyses, and sublingual endothelial glycocalyx dimensions in the selected kidney transplant patients. A low C/D ratio (C/D ratio &lt, 1.05 ng/mL&times, 1/mg) was linked with higher C2 tacrolimus blood concentrations (19.2 &plusmn, 8.7 &micro, g/L vs. 12.2 &plusmn, 5.2 &micro, g/L respectively, p = 0.001) and higher degrees of nephrotoxicity despite comparable trough levels (6.3 &plusmn, 2.4 &micro, g/L vs. 6.6 &plusmn, 2.2 &micro, p = 0.669). However, the tacrolimus metabolism rate did not affect the pulse wave velocity or glycocalyx in patients. In renal tubular epithelial cells exposed to tacrolimus according to a fast metabolism pharmacokinetic profile it led to reduced viability and increased Fn14 expression. We conclude from our data that the C/D ratio may be an appropriate tool for identifying patients at risk of developing calcineurin-inhibitor toxicity.

Boras et al. demonstrate that Skap2, via interaction with WASp, regulates actin polymerization and binding of talin-1 and kindlin-3 to the β2 integrin, thereby being indispensable for β2 integrin activation and neutrophil recruitment., Integrin activation is required for neutrophil functions. Impaired integrin activation on neutrophils is the hallmark of leukocyte adhesion deficiency (LAD) syndrome in humans, characterized by impaired leukocyte recruitment and recurrent infections. The Src kinase–associated phosphoprotein 2 (Skap2) is involved in integrin functions in different leukocyte subtypes. However, the role of Skap2 in β2 integrin activation and neutrophil recruitment is unknown. In this study, we demonstrate the crucial role of Skap2 in regulating actin polymerization and binding of talin-1 and kindlin-3 to the β2 integrin cytoplasmic domain, thereby being indispensable for β2 integrin activation and neutrophil recruitment. The direct interaction of Skap2 with the Wiskott–Aldrich syndrome protein via its SH3 domain is critical for integrin activation and neutrophil recruitment in vivo. Furthermore, Skap2 regulates integrin-mediated outside-in signaling events and neutrophil functions. Thus, Skap2 is essential to activate the β2 integrins, and loss of Skap2 function is sufficient to cause a LAD-like phenotype in mice.

Intracellular trafficking processes play a key role for the establishment and maintenance of membrane surfaces in renal epithelia. Therefore, dysfunctions of these trafficking processes could be key events and important determinants in the onset and progression of diseases. The presence of cellular vacuoles-observed in many histologic analyses of renal diseases-is a macroscopic hint for disturbed intracellular trafficking processes. However, how vacuoles develop and which intracellular pathways are directly affected remain largely unknown. Previous studies showed that in some cases, vacuolization is linked to malfunction of the Vac14 complex. This complex, including the scaffold protein Vac14, the lipid kinase PIKfyve, and its counteracting lipid phosphatase Fig4, regulates intracellular phosphatidylinositol phosphate levels, which in turn, control the maturation of early-into-late endosomes, as well as the processing of autophagosomes into autophagolysosomes. Here, we analyzed the role of Vac14 in mice and observed that the nephron-specific knockin of the PIKfyve-binding-deficient Vac14

Ischemia–reperfusion injury (IRI) remains a key component of graft damage during transplantation. Erythropoietin (EPO) induces anti-inflammatory and anti-apoptotic effects via the EPOR2/βcR2 complex, with a potential risk of thrombosis. Previous work indicates that EPO has EPOR2/βcR2-independent protective effects via direct effects on the endothelium. As the EPOR2/βcR2 receptor has a very low affinity for EPO, we aimed to test the hypothesis that EPO doses below the level that stimulate this receptor elicit cytoprotective effects via endothelial stimulation in a porcine liver transplantation model. Landrace pigs underwent allogenic liver transplantation (follow-up: 6 h) with a portojugular shunt. Animals were divided into two groups: donor and recipient treatment with low-dose EPO (65 IU/kg) or vehicle, administered 6 h before cold perfusion and 30 min after warm reperfusion. Fourteen of 17 animals (82.4%) fulfilled the inclusion criteria. No differences were noted in operative values between the groups including hemoglobin, cold or warm ischemic time. EPO-treated animals showed a significantly lower histopathology score, reduced apoptosis, oxidative stress, and most important a significant up-regulation of endothelial nitric oxide (NO) synthase (eNOS). Donor and recipient treatment with low-dose EPO reduces the hepatic IRI via EPOR2/βcR2-independent cytoprotective mechanisms and represents a clinically applicable way to reduce IRI.

The reduced number of circulating stem/progenitor cells that is found in chronic kidney disease (CKD) patients may contribute to impaired angiogenic repair and decreased capillary density in the heart. Cell therapy with bone marrow-derived cells (BMDCs) has been shown to induce positive effects on the microvasculature and cardiac function, most likely due to secretion of growth factors and cytokines, all of which are present in the conditioned medium (CM); however, this is controversial. Here we showed that treatment with BMDC or CM restored vascular density and decreased the extent of fibrosis in a rat model of CKD, the 5/6 nephrectomy. Engraftment and differentiation of exogenous BMDCs could not be detected. Yet CM led to the mobilization and infiltration of endogenous circulating cells into the heart. Cell recruitment was facilitated by the local expression of pro-inflammatory factors such as the macrophage chemoattractant protein-1, interleukin-6, and endothelial adhesion molecules. Consistently, in vitro assays showed that CM increased endothelial adhesiveness to circulating cells by upregulating the expression of adhesion molecules, and stimulated angiogenesis/endothelial tube formation. Overall, our results suggest that both treatments exert vasculoprotective effects on the heart of uremic rats by stimulating endogenous repair mechanisms.

Acute cellular renal allograft rejection (AR) frequently occurs after kidney transplantations. It is a sterile T-cell mediated inflammation leading to increased local glucose metabolism. Here we demonstrate in an allogeneic model of Brown Norway rat kidneys transplanted into uninephrectomized Lewis rats the successful implementation of the recently developed glucose chemical exchange saturation transfer (glucoCEST) magnetic resonance imaging. This technique is a novel method to assess and differentiate AR. Renal allografts undergoing AR showed significantly increased glucoCEST contrast ratios of cortex to medulla of 1.61 compared to healthy controls (1.02), syngeneic Lewis kidney to Lewis rat transplants without rejection (0.92), kidneys with ischemia reperfusion injury (0.99) and kidneys affected by cyclosporine A toxicity (1.10). Receiver operating characteristic curve analysis showed an area under the curve value of 0.92, and the glucoCEST contrast ratio predicted AR with a sensitivity of 100% and a specificity of 69% at a threshold level over 1.08. In defined animal models of kidney injuries, the glucoCEST contrast ratios of cortex to medulla correlated positively with mRNA expression levels of T-cell markers (CD3, CD4, CD8a/b), but did not correlate to impaired renal perfusion. Thus, the glucoCEST parameter may be valuable for the assessment and follow up treatment of AR.

Item does not contain fulltext Noninvasive methods to diagnose and differentiate acute cellular rejection from acute tubular necrosis or acute calcineurin inhibitor toxicity are still missing. Because T lymphocytes play a decisive role in early states of rejection, we investigated the suitability and feasibility of antibody-mediated contrast-enhanced ultrasound by using microbubbles targeted to CD3(+) , CD4(+) , or CD8(+) T cells in different models of renal disease. In an established rat renal transplantation model, CD3-mediated ultrasound allows the detection of acute rejection as early as on postoperative day 2. Ultrasound signal intensities increased with the severity of inflammation. Further, an early response to therapy could be monitored by using contrast-enhanced sonography. Notably, acute tubular necrosis occurring after ischemia-reperfusion injury as well as acute calcineurin inhibitor toxicity could easily be differentiated. Finally, the quantified ultrasound signal correlated significantly with the number of infiltrating T cells obtained by histology and with CD3 mRNA levels, as well as with chemokine CXCL9, CXCL11, and CCL19 mRNA but not with KIM-1 mRNA expression, thereby representing the severity of graft inflammation but not the degree of kidney injury. In summary, we demonstrate that antibody-mediated contrast-enhanced ultrasound targeting T lymphocytes could be a promising tool for an easy and reproducible assessment of acute rejection after renal transplantation. 01 mei 2016

Background Major thoracic wall resections require the implantation of foreign materials for reconstruction and stabilization. Recently, biological collagen matrixes have emerged as an alternative to the routinely used synthetic materials. Materials and Methods Retrospectively, we analyzed our initial experience of chest wall reconstruction on large defects using a cross-linked porcine dermal acellular collagen matrix mesh with a thickness of 1.5 mm. Results Six sarcoma patients with a mean age of 46 (22–66) years underwent chest wall resections. Complete thoracic wall defects (mean area 149 cm 2 ) ranged from 8 × 10 to 15 × 20 cm in size. In the majority of cases, only mobilized subcutaneous tissue and skin were used for soft-tissue coverage of the implanted porcine collagen matrix patches. Implantation and postoperative courses were uneventful in all patients. No local infections or wound healing problems occurred. The collagen material resulted in durable and good to excellent chest wall stability in clinical follow-ups, and on computed tomography scans spanning over 3.5 years. Histological examination showed integration, neovascularization, and long-term persistence of the collagen matrix on late reoperation of one patient. Conclusion Acellular porcine dermal collagen matrix is a feasible and reliable biological patch material for reconstruction of the thoracic wall. Excellent wound healing and long-term stability are achieved even in large defects or complete sternal replacements.

358 Background: To investigate the prognostic value of PD-1 and PD-L1 expression in patients with high-grade upper tract urothelial carcinoma (UTUC). Methods: Tissue microarrays were created using 448 patients from the International UTUC collaboration who underwent extirpative surgery for high-grade UTUC and stained for PD-1 (antibody (AB): NAT105, diluted 1:250 from Ventana) and PD-L1 (AB: E1L3N prediluted from Cell Signaling). PD-1 and PD-L1 expression was assessed in a semi-quantitative fashion and any percentage of staining of the tumor cells (PD-L1) and tumor-infiltrating lymphocytes (PD-1) was considered positive. Univariate (UVA) and multivariate analyses (MVA) were performed to assess independent prognosticators of oncological outcomes. No funding was received. Results: Median age of the cohort was 69.2 years and 56.5% of patients were male. PD-L1 and PD-1 were positive in 24.1% and 37.5% of patients. PD-L1 positivity was associated with favorable pathological stage, where as PD-1 positivity was significantly associated with pelvicalyceal location, lymph node metastases, non-organ confined disease, presence of lymphovascular invasion, sessile architecture, necrosis, concomitant CIS, and history of non-muscle invasive bladder cancer. PD-L1 positivity was not significantly associated with survival outcomes. In Cox regression UVA, PD-1 positivity was associated with worse recurrence-free survival (RFS) (HR 1.5 (95%CI 1.08-2.14, p=0.016)), cancer-specific survival (CSS) (HR 1.5 (95%CI 1.07-2.19, p=0.021)), and overall survival (OS) (HR 1.5 (95%CI 1.10-1.97, p=0.009)). However in MVA, PD-1 positivity was not found to be an independent predictor of RFS, CSS or OS. Conclusions: PD-1 positivity of tumor-infiltrating lymphocytes was associated with adverse pathological criteria and was a significant prognosticator for RFS, CSS and OS on UVA in patients treated with extirpative surgery for high-grade UTUC in a large, multi-institutional cohort. In MVA, the independent prognostic value of PD-1 was not confirmed. PD-L1 positivity was associated with lower tumor stage, but not with other pathological characteristics or survival outcomes.