The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody-mediated liver allograft rejection at the 11th (Paris, France, June 5-10, 2011), 12th (Comandatuba, Brazil, August 19-23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5-10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody-mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.

A key event in bone resorption is the binding of osteoclasts to the mineral matrix of bone surfaces. A candidate for mediating this binding is osteopontin, a major cell-and hydroxyapatite-binding protein synthesized by osteoblasts. In support of this hypothesis is the fact that the synthesis of osteopontin is stimulated by calcitriol (1,25-dihydroxyvitamin(D3), a substance that induces bone resorption. The present study demonstrates that osteopontin is highly enriched at regions of the bone surface where osteoclasts are anchored. Furthermore, the vitronectin receptor, which has known specificity for osteopontin, is shown preferentially localized at the corresponding area of the osteoclast plasma membrane. The results thus support the hypothesis that osteoclasts when resorbing bone are anchored by osteopontin bound both to the mineral of bone matrix and to a vitronectin receptor on the osteoclast plasma membrane.More than 100 years have passed since Kolliker gave the name "Osteoklast" to a large multinucleated cell observed along bone surfaces and suggested a role for the cell in bone resorption (1). It is now well established that osteoclasts are derived from a bone-marrow cell reaching the bone surfaces by means of blood-borne mononuclear precursor cells (2). The stimulus is provided by other bone cells, which when appropriately stimulated, produce factors that induce recruitment of osteoclast progenitor cells to select bone surfaces (3). Osteoclasts are in contact with mineralized bone matrix at two modified cell surface areas, a clear zone and a ruffled border (4, 5) ( Fig. 1). Active bone resorption is confined to the ruffled border area, where an acidic milieu is maintained. The clear zone is located immediately adjacent to the ruffled border and is thought to provide the osteoclast with a tight attachment to bone, thereby sealing off the ruffled border zone (5, 6). The mechanism for this vital attachment has remained an enigma. It has, however, been suggested that a vitronectin receptor identified on isolated osteoclasts (7) may be involved (8).Over recent years several noncollagenous matrix proteins of bone have been isolated and characterized. At least two of these proteins-i.e., osteopontin and bone sialoprotein-are acidic and bind tightly to hydroxylapatite (9, 10). A functional Arg-Gly-Asp (RGD) cell-binding sequence has been identified in both proteins by cDNA cloning and sequencing (11,12). A receptor for the proteins on cultured osteoblastic cells appears to be the vitronectin receptor (13). Both osteopontin and bone sialoproteins are products of osteoblasts, contain stretches of acidic amino acids, and are phosphorylated. Osteopontin and bone sialoprotein represent distinct gene products. The synthesis of only one of the proteins, osteopontin, is stimulated by calcitriol (14, 15), which is known to induce bone resorption. Thus, osteopontin is a candidate for mediating binding of osteoclasts to bone at the clear zone. In the present study this hypothesis was tested by using ultrastructural ...

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Human bone marrow mesenchymal stem cells (hMSCs) represent an appealing source of adult stem cells for cell therapy and tissue engineering, as they are easily obtained and expanded while maintaining their multilineage differentiation potential. All current protocols for in vitro culture of hMSCs include fetal bovine serum (FBS) as nutritional supplement. FBS is an undesirable additive to cells that are expanded for therapeutic purposes in humans because the use of FBS carries the risk of transmitting viral and prion diseases and proteins that may initiate xenogeneic immune responses. In the present study, we have therefore investigated if autologous serum (AS) or allogeneic human serum (alloHS) could replace FBS for the expansion of hMSCs in vitro. We discovered that the choice of serum affected hMSCs at several different levels.First, hMSCs in AS proliferated markedly faster than hMSCs in FBS, whereas use of alloHS resulted in hMSC growth arrest and death. Second, hMSCs in FBS differentiated more rapidly toward mesenchymal lineages compared with hMSCs in AS. Interestingly, genome-wide microarray analysis identified several transcripts involved in cell cycle and differentiation that were differentially regulated between hMSCs in FBS and AS. Finally, several transcripts, including some involved in cell cycle inhibition, were upregulated in hMSCs in FBS at a late passage, whereas the hMSC transcriptome in AS was remarkably stable. Thus, hMSCs may be expanded rapidly and with stable gene expression in AS in the absence of growth factors, whereas FBS induces a more differentiated and less stable transcriptional profile. Stem Cells 2005;23:1357-1366

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Lymphocyte homing to secondary lymphoid tissue is defined by a multistep sequence of interactions between lymphocytes and endothelial cells in high endothelial venules (HEVs). After initial selectin-mediated tethering and rolling, firm adhesion of lymphocytes requires rapid upregulation of lymphocyte integrin adhesiveness. This step is mediated in part by the HEV-derived chemokine SLC (secondary lymphoid-tissue chemokine, or CCL21) that binds to the CC chemokine receptor (CCR)7 on lymphocytes. However, the CC chemokine ELC (Epstein-Barr virus–induced molecule 1 ligand chemokine, or CCL19) shares the same receptor, and ELC transcripts have been observed in the T cell areas of lymphoid organs. Here, we show that perivascular ELC is transcytosed to the luminal surfaces of HEVs and enables efficient T cell homing to lymph nodes. In situ hybridization on sections of human tonsil showed no ELC mRNA in HEVs, but immunostaining revealed ELC protein in cytoplasmic vesicles of HEV cells. Furthermore, ELC injected into the footpads of mice entered the draining lymph nodes and was presented by HEVs. Finally, intracutaneous injections of ELC in mice lacking functionally relevant ELC and SLC (plt/plt mice) restored T cell trafficking to draining lymph nodes as efficiently as SLC. We conclude that perivascular ELC is transcytosed to the luminal surfaces of HEVs and participates in CCR7-mediated triggering of lymphocyte arrest.

A key element in diabetic nephropathy (DN) is changes in the extracellular matrix (ECM) of several of the components in the kidney. From a clinical perspective, the changes seen in the ECM are important both in diagnostics and for prognostic and therapeutic purposes. In the current review, we present some of the central clinical issues related to DN, as well as the most relevant changes to the ECM from a diagnostic point of view, and also discuss some of the changes observed in one of the important ECM components, the proteoglycans (PGs). Our aim is not to cover all relevant research in this rather wide field, ranging from clinical trials to studies on microRNA and other important regulators of kidney function, but to focus particularly on some key issues related to PG changes in DN. Clinical Perspectives on DNAccording to estimates from the International Diabetes Federation, the worldwide prevalence of diabetes is estimated to increase from 285 million persons in 2010 to 439 millions in 2030, a relative increase of 50% (Shaw et al. 2010). Among patients with type 1 diabetes, the incidence of DN has apparently decreased from 30-35% in the cohorts who developed diabetes 40 to 50 years ago to 10-15% in recent cohorts (Bojestig et al. 1994;Hovind et al. 2003). However, due to the increase in type 2 diabetes, the absolute prevalence of DN has increased over the past two decades. In 2009, DN was reported to be the cause of 44% of all cases of end-stage renal disease (ESRD) in the United States (www.usrds.org), with an incidence of 155 diabetic patients developing ESRD per million each year. This fact was earlier announced as a "medical catastrophe of world-wide dimensions" (Ritz et al. 465073J HCXXX10.1369/0022155412465073Kolset et al.Extracellular Matrix and Diabetic Nephropathy 2012© The Author(s) 2010 Reprints and permission: sagepub.com/journalsPermissions. SummaryDiabetic nephropathy (DN) is a serious complication in diabetes. Major typical morphological changes are the result of changes in the extracellular matrix (ECM). Thus, basement membranes are thickened and the glomerular mesangial matrix and the tubulointerstitial space are expanded, due to increased amounts of ECM. One important ECM component, the proteoglycans (PGs), shows a more complex pattern of changes in DN. PGs in basement membranes are decreased but increased in the mesangium and the tubulointerstitial space. The amounts and structures of heparan sulfate chains are changed, and such changes affect levels of growth factors regulating cell proliferation and ECM synthesis, with cell attachment affecting endothelial cells and podocytes. Enzymes modulating heparan sulfate structures, such as heparanase and sulfatases, are implicated in DN. Other enzyme classes also modulate ECM proteins and PGs, such as matrix metalloproteinases (MMPs) and serine proteases, such as plasminogen activator, as well as their corresponding inhibitors. The levels of these enzymes and inhibitors are changed in plasma and in the kidneys in DN. Several growth factors, signali...

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