Shohta Kodama

VEGF-A induces tumor and sentinel lymph node lymphangiogenesis and promotes lymphatic metastasis

The mechanisms of tumor metastasis to the sentinel lymph nodes are poorly understood. Vascular endothelial growth factor (VEGF)-A plays a principle role in tumor progression and angiogenesis; however, its role in tumor-associated lymphangiogenesis and lymphatic metastasis has remained unclear. We created transgenic mice that overexpress VEGF-A and green fluorescent protein specifically in the skin, and subjected them to a standard chemically-induced skin carcinogenesis regimen. We found that VEGF-A not only strongly promotes multistep skin carcinogenesis, but also induces active proliferation of VEGF receptor-2–expressing tumor-associated lymphatic vessels as well as tumor metastasis to the sentinel and distant lymph nodes. The lymphangiogenic activity of VEGF-A–expressing tumor cells was maintained within metastasis-containing lymph nodes. The most surprising finding of our study was that even before metastasizing, VEGF-A–overexpressing primary tumors induced sentinel lymph node lymphangiogenesis. This suggests that primary tumors might begin preparing their future metastatic site by producing lymphangiogenic factors that mediate their efficient transport to sentinel lymph nodes. This newly identified mechanism of inducing lymph node lymphangiogenesis likely contributes to tumor metastasis, and therefore, represents a new therapeutic target for advanced cancer and/or for the prevention of metastasis.

Reversal of established autoimmune diabetes by restoration of endogenous β cell function

In NOD (nonobese diabetic) mice, a model of autoimmune diabetes, various immunomodulatory interventions prevent progression to diabetes. However, after hyperglycemia is established, such interventions rarely alter the course of disease or allow sustained engraftment of islet transplants. A proteasome defect in lymphoid cells of NOD mice impairs the presentation of self antigens and increases the susceptibility of these cells to TNF-alpha-induced apoptosis. Here, we examine the hypothesis that induction of TNF-alpha expression combined with reeducation of newly emerging T cells with self antigens can interrupt autoimmunity. Hyperglycemic NOD mice were treated with CFA to induce TNF-alpha expression and were exposed to functional complexes of MHC class I molecules and antigenic peptides either by repeated injection of MHC class I matched splenocytes or by transplantation of islets from nonautoimmune donors. Hyperglycemia was controlled in animals injected with splenocytes by administration of insulin or, more effectively, by implantation of encapsulated islets. These interventions reversed the established beta cell-directed autoimmunity and restored endogenous pancreatic islet function to such an extent that normoglycemia was maintained in up to 75% of animals after discontinuation of treatment and removal of islet transplants. A therapy aimed at the selective elimination of autoreactive cells and the reeducation of T cells, when combined with control of glycemia, is thus able to effect an apparent cure of established type 1 diabetes in the NOD mouse.

CD4+ Vα14 natural killer T cells are essential for acceptance of rat islet xenografts in mice

Pancreatic islet transplantation represents a potential treatment for insulin-dependent diabetes mellitus. However, the precise cellular and molecular mechanisms of the immune reactions against allogeneic and xenogeneic transplanted islets remain unclear. Here, we demonstrate that CD4(+) Valpha14 natural killer T (NKT) cells, a recently identified lymphoid cell lineage, are required for the acceptance of intrahepatic rat islet xenografts. An anti-CD4 mAb, administrated after transplantation, allowed islet xenografts to be accepted by C57BL/6 mice, with no need for immunosuppressive drugs. The dose of anti-CD4 mAb was critical, and the beneficial effect appeared to be associated with the reappearance of CD4(+) NKT cells at around 14 days after transplantation. Interestingly, rat islet xenografts were rejected, despite the anti-CD4 mAb treatment, in Valpha14 NKT cell-deficient mice, which exhibit the normal complement of conventional lymphoid cells; adoptive transfer of Valpha14 NKT cells into Valpha14 NKT cell-deficient mice restored the acceptance of rat islet xenografts. In addition, rat islet xenografts were accepted by Valpha14 NKT mice having only Valpha14 NKT cells and no other lymphoid cells. These results indicate that Valpha14 NKT cells play a crucial role in the acceptance of rat islet xenografts in mice treated with anti-CD4 antibody, probably by serving as immunosuppressive regulatory cells.

Bioengineered Three-Layered Robust and Elastic Artery Using Hemodynamically-Equivalent Pulsatile Bioreactor

Background— There is an essential demand for tissue engineered autologous small-diameter vascular graft, which can function in arterial high pressure and flow circulation. We investigated the potential to engineer a three-layered robust and elastic artery using a novel hemodynamically-equivalent pulsatile bioreactor. Methods and Results— Endothelial cells (ECs), smooth muscle cells (SMCs), and fibroblasts were harvested from bovine aorta. A polyglycolic acid (PGA) sheet and a polycaprolactone sheet seeded with SMCs, and a PGA sheet seeded with fibroblast, were wrapped in turn on a 6-mm diameter silicone tube and incubated in culture medium for 30 days. The supporting tube was removed, and the lumen was seeded with ECs and incubated for another 2 days. The pulsatile bioreactor culture, under regulated gradual increase in flow and pressure from 0.2 (0.5/0) L/min and 20 (40/15) mm Hg to 0.6 (1.4/0.2) L/min and 100 (120/80) mm Hg, was performed for an additional 2 weeks (n=10). The engineered vessels acquired distinctly similar appearance and elasticity as native arteries. Scanning electron microscopic examination and Von Willebrand factor staining demonstrated the presence of ECs spread over the lumen. Elastica Van Gieson and Masson Tricrome Stain revealed ample production of elastin and collagen in the engineered grafts. Alpha-SMA and calponin staining showed the presence of SMCs. Tensile tests demonstrated that engineered vessels acquired equivalent ultimate strength and similar elastic characteristics as native arteries (Ultimate Strength of Native: 882±133 kPa, Engineered: 827±155 kPa, each n=8). Conclusions— A robust and elastic small-diameter artery was engineered from three types of vascular cells using the physiological pulsatile bioreactor.

The therapeutic potential of tumor necrosis factor for autoimmune disease: a mechanistically based hypothesis

Abstract.Excess levels of tumor necrosis factor-α (TNF-α) have been associated with certain autoimmune diseases. Under the rationale that elevated TNF-α levels are deleterious, several anti-TNF-α therapies are now available to block the action of TNF-α in patients with autoimmune diseases with a chronic inflammatory component to the destructive process. TNF-α antagonists have provided clinical benefit to many patients, but their use also is accompanied by new or aggravated forms of autoimmunity. Here we propose a mechanistically based hypothesis for the adverse events observed with TNF-α antagonists, and argue for the opposite therapeutic strategy: to boost or restore TNF-α activity as a treatment for some forms of autoimmunity. Activation defects in the transcription factor nuclear factor κB leave autoreactive T cells sensitive to TNF-α-induced apoptosis. Treatment with TNF-α, by destroying autoreactive T cells, appears to be a highly targeted strategy to interrupt the pathogenesis of type 1 diabetes, lupus and certain forms of autoimmunity.

Human Pancreatic Islet-Derived Progenitor Cell Engraftment in Immunocompetent Mice

The potential for the use of stem/progenitor cells for the restoration of injured or diseased tissues has garnered much interest recently, establishing a new field of research called regenerative medicine. Attention has been focused on embryonic stem cells derived from human fetal tissues. However, the use of human fetal tissue for research and transplantation is controversial. An alternative is the isolation and utilization of multipotent stem/progenitor cells derived from adult donor tissues. We have previously reported on the isolation, propagation, and partial characterization of a population of stem/progenitor cells isolated from the pancreatic islets of Langerhans of adult human donor pancreata. Here we show that these human adult tissue-derived cells, nestin-positive islet-derived stem/progenitor cells, prepared from human adult pancreata survive engraftment and produce tissue chimerism when transplanted into immunocompetent mice either under the kidney capsule or by systemic injection. These xenografts seem to induce immune tolerance by establishing a mixed chimerism in the mice. We propose that a population of stem/progenitor cells isolated from the islets of the pancreas can cross xenogeneic transplantation immune barriers, induce tissue tolerance, and grow.

Mesenchymal Stromal Cells Improve Salivary Function and Reduce Lymphocytic Infiltrates in Mice with Sjogren's-Like Disease

Background Non-obese diabetic (NOD) mice develop Sjögrens-like disease (SS-like) with loss of saliva flow and increased lymphocytic infiltrates in salivary glands (SGs). There are recent reports using multipotent mesenchymal stromal cells (MSCs) as a therapeutic strategy for autoimmune diseases due to their anti-inflammatory and immunomodulatory capabilities. This paper proposed a combined immuno- and cell-based therapy consisting of: A) an injection of complete Freunds adjuvant (CFA) to eradicate autoreactive T lymphocytes, and B) transplantations of MSCs to reselect lymphocytes. The objective of this was to test the effectiveness of CD45−/TER119− cells (MSCs) in re-establishing salivary function and in reducing the number of lymphocytic infiltrates (foci) in SGs. The second objective was to study if the mechanisms underlying a decrease in inflammation (focus score) was due to CFA, MSCs, or CFA+MSCs combined. Methodology/Principal Findings Donor MSCs were isolated from bones of male transgenic eGFP mice. Eight week-old female NOD mice received one of the following treatments: insulin, CFA, MSC, or CFA+MSC (combined therapy). Mice were followed for 14 weeks post-therapy. CD45−/TER119− cells demonstrated characteristics of MSCs as they were positive for Sca-1, CD106, CD105, CD73, CD29, CD44, negative for CD45, TER119, CD11b, had high number of CFU-F, and differentiated into osteocytes, chondrocytes and adipocytes. Both MSC and MSC+CFA groups prevented loss of saliva flow and reduced lymphocytic infiltrations in SGs. Moreover, the influx of T and B cells decreased in all foci in MSC and MSC+CFA groups, while the frequency of Foxp3+ (Treg) cell was increased. MSC-therapy alone reduced inflammation (TNF-α, TGF-β), but the combination of MSC+CFA reduced inflammation and increased the regenerative potential of SGs (FGF-2, EGF). Conclusions/Significance The combined use of MSC+CFA was effective in both preventing saliva secretion loss and reducing lymphocytic influx in salivary glands.

Characterization of Mouse Spleen Cells by Subtractive Proteomics

Major analytical challenges encountered by shotgun proteome analysis include both the diversity and dynamic range of protein expression. Often new instrumentation can provide breakthroughs in areas where other analytical improvements have not been successful. In the current study, we utilized new instrumentation (LTQ FT) to characterize complex protein samples by shotgun proteomics. Proteomic analyses were performed on murine spleen tissue separated by magnetic beads into distinct CD45− and CD45+ cell populations. Using shotgun protein analysis we identified ∼2,000 proteins per cell group by over 12,000 peptides with mass deviations of less than 4.5 ppm. Datasets obtained by LTQ FT analysis provided a significant increase in the number of proteins identified and greater confidence in those identifications and improved reproducibility in replicate analyses. Because CD45− and not CD45+ cells are able to regenerate functional pancreatic islet cells in a mouse model of type I diabetes, protein expression was further compared by a subtractive proteomic approach in search of an exclusive protein expression profile in CD45− cells. Characterization of the proteins exclusively identified in CD45− cells was performed using gene ontology terms via the Javascript GoMiner. The CD45− cell subset readily revealed proteins involved in development, suggesting the persistence of a fetal stem cell in an adult animal.

IKKβ regulates essential functions of the vascular endothelium through kinase-dependent and -independent pathways

Vascular endothelium provides a selective barrier between the blood and tissues, participates in wound healing and angiogenesis, and regulates tissue recruitment of inflammatory cells. Nuclear factor (NF)-κB transcription factors are pivotal regulators of survival and inflammation, and have been suggested as potential therapeutic targets in cancer and inflammatory diseases. Here we show that mice lacking IKKβ, the primary kinase mediating NF-κB activation, are smaller than littermates and born at less than the expected Mendelian frequency in association with hypotrophic and hypovascular placentae. IKKβ-deleted endothelium manifests increased vascular permeability and reduced migration. Surprisingly, we find that these defects result from loss of kinase-independent effects of IKKβ on activation of the serine-threonine kinase, Akt. Together, these data demonstrate essential roles for IKKβ in regulating endothelial permeability and migration, as well as an unanticipated connection between IKKβ and Akt signalling.

Hepatic resection is not enough for hepatocellular carcinoma : a follow-up study of 92 patients

We followed up 92 patients who underwent curative hepatic resection for hepatocellular carcinoma between 1982 and 1991. The long-term survival rates for these 92 patients for 1, 3, and 5 years were 98.8, 81.6, and 57.3%, respectively. As of May 1991, the carcinoma had recurred in 52 patients (56.5%). Recurrent tumors usually occurred in the residual liver within 3 years after surgery but were not always located near the primary lesion. The biologic characteristics of the primary tumors, such as serum alpha-fetoprotein, tumor size, number of tumors, and portal involvement, were closely related to recurrence and long-term survival. However, the type of hepatectomy performed on the primary tumor had little influence on recurrence or long-term survival. We conclude that recurrence cannot be avoided by hepatic resection alone, much less with limited resection; postoperative positive adjuvant therapy is required to prevent recurrence for patients with satellite nodule and/or portal involvement.