John G. Sharp

Outcome of high-dose therapy and autologous transplantation in non-Hodgkin's lymphoma based on the presence of tumor in the marrow or infused hematopoietic harvest.

PURPOSE To evaluate the outcomes in 65 consecutive patients with non-Hodgkins lymphoma (NHL) undergoing high-dose therapy (HDT) and autologous transplantation based on initial marrow involvement and the presence or absence of minimal disease in the hematopoietic harvests. PATIENTS AND METHODS Patients with any history of histologic evidence of marrow tumor underwent autologous peripheral-blood stem-cell transplantation (PSCT), whereas others underwent autologous bone marrow transplantation (ABMT). Patients who underwent ABMT were further segregated retrospectively into two groups depending on whether there was evidence by cell culture and/or Southern analysis of minimal tumor in the marrow harvest. RESULTS Comparable proportions (58% to 60%) of patients in each of the two groups (PSCT and ABMT) achieved a complete clinical remission (CR) at 100 days. For patients who achieve a CR, the actuarial relapse-free survival rate at 5 years for PSCT patients who received a tumor-negative apheresis harvest was 64%, compared with 57% for patients who received a tumor-negative bone marrow harvest and 17% for patients who received a histologically negative but minimally contaminated bone marrow harvest. Lymphoma grade and phenotype were not significant predictors of outcome. CONCLUSION The observation that survival was significantly better in the groups of patients who received tumor-negative harvests and worse for patients who received minimally contaminated harvests suggests that tumor cells, even at minimal levels, reinfused in the transplanted harvest are responsible for progression in a proportion of patients who achieve a CR following HDT, although other biologic characteristics of the tumor could also be important. A relatively good outcome can be achieved with HDT and PSCT, even in patients with a significant marrow tumor burden.

Phase I Trial of an Antisense Oligonucleotide OL(1)p53 in Hematologic Malignancies

PURPOSE The phosphoprotein p53 is involved in transcriptional regulation and is detected in hematologic malignancies. In vitro incubation of acute myelogenous leukemia with OL(1)p53, a 20-mer phosphorothioate oligonucleotide complementary to p53 mRNA, results in leukemic cell death. A phase I dose-escalating trial was conducted to determine the toxicity of OL(1)p53 following systemic administration to patients with hematologic malignancies. PATIENTS AND METHODS Sixteen patients with either refractory acute myelogenous leukemia (n = 6) or advanced myelodysplastic syndrome (n = 10) participated in the trial. Patients were given OL(1)p53 at doses of 0.05 to 0.25 mg/kg/h for 10 days by continuous intravenous infusion. RESULTS No specific toxicity was directly related to the administration of OL(1)p53. One patient developed transient nonoliguric renal failure. One patient died of anthracycline-induced cardiac failure. Approximately 36% of the administered dose of OL(1)p53 was recovered intact in the urine. Plasma concentrations and area under the plasma concentration curves were linearly correlated with dose. Leukemic cell growth in vitro was inhibited as compared with pretreatment samples. There were no clinical complete responses. CONCLUSION A phosphorothioate oligonucleotide, OL(1)p53, can be administered systemically without complications. This type of modified oligonucleotide can be administered without complete degradation, as it was recovered from the urine intact. This oligonucleotide may be useful in combination with currently available chemotherapy agents for the treatment of malignancies.

Human Immunodeficiency Virus Type 1 Pathobiology Studied in Humanized BALB/c-Rag2−/−γc−/− Mice

ABSTRACT The specificity of human immunodeficiency virus type 1 (HIV-1) for human cells precludes virus infection in most mammalian species and limits the utility of small animal models for studies of disease pathogenesis, therapy, and vaccine development. One way to overcome this limitation is by human cell xenotransplantation in immune-deficient mice. However, this has proved inadequate, as engraftment of human immune cells is limited (both functionally and quantitatively) following transplantation of mature human lymphocytes or fetal thymus/liver. To this end, a human immune system was generated from umbilical cord blood-derived CD34+ hematopoietic stem cells in BALB/c-Rag2−/−γc−/− mice. Intrapartum busulfan administration followed by irradiation of newborn pups resulted in uniform engraftment characterized by human T-cell development in thymus, B-cell maturation in bone marrow, lymph node development, immunoglobulin M (IgM)/IgG production, and humoral immune responses following ActHIB vaccination. Infection of reconstituted mice by CCR5-coreceptor utilizing HIV-1ADA and subtype C 1157 viral strains elicited productive viral replication and lymphadenopathy in a dose-dependent fashion. We conclude that humanized BALB/c-Rag2−/−γc−/− mice represent a unique and valuable resource for HIV-1 pathobiology studies.

Transplanted BM and BM side population cells contribute progeny to the lung and liver in irradiated mice

BACKGROUND BM cells have been shown to give rise to progeny of various cell lineages, including cells in lung and liver. This investigation evaluated whether purified BM mononuclear cells and side population (SP) cells that have hematopoietic stem-cell activity also had this property; whether a TBI preparative regimen was necessary for engraftment; and where BM-derived cells were engrafted. METHODS Either 1-3 million BM mononuclear cells or 2000 BM SP cells from transgenic enhanced green fluorescent protein-expressing (EGFP) mice were transplanted i.v. to unirradiated or 7-9.5 Gy irradiated recipients. RESULTS Flow cytometric analysis showed that lung cells (mean 45%, range 4-70%) and liver cells (mean 4%, range 0.4-8.3%) from irradiated, but not unirradiated recipients, were EGFP donor-derived. Similar results were obtained transplanting BM mononuclear cells or SP cells. Morphologically, donor-derived cells in the lung were primarily monocytes and macrophages. Additionally, lung fibroblasts and Type I, but not Type II, alveolar cells and rare cells in the bronchial epithelium were donor BM derived. In the liver, Kupffer cells, inflammatory cells and small clusters of hepatocytes, but not bile duct cells, were donor-derived. DISCUSSION BM mononuclear and SP cells generated progeny in some compartments of the lung and liver, but only in TBI recipients. Stem cells in BM can contribute to repair of tissue injury in some compartments, but not to the same extent in the lung and liver.

Long-Term Cigarette Smoke Exposure in a Mouse Model of Ciliated Epithelial Cell Function

Exposure to cigarette smoke is associated with airway epithelial mucus cell hyperplasia and a decrease in cilia and ciliated cells. Few models have addressed the long-term effects of chronic cigarette smoke exposure on ciliated epithelial cells. Our previous in vitro studies showed that cigarette smoke decreases ciliary beat frequency (CBF) via the activation of protein kinase C (PKC). We hypothesized that chronic cigarette smoke exposure in an in vivo model would decrease airway epithelial cell ciliary beating in a PKC-dependent manner. We exposed C57BL/6 mice to whole-body cigarette smoke 2 hours/day, 5 days/week for up to 1 year. Tracheal epithelial cell CBF and the number of motile cells were measured after necropsy in cut tracheal rings, using high-speed digital video microscopy. Tracheal epithelial PKC was assayed according to direct kinase activity. At 6 weeks and 3 months of smoke exposure, the baseline CBF was slightly elevated (~1 Hz) versus control mice, with no change in β-agonist-stimulated CBF between control mice and cigarette smoke-exposed mice. By 6 months of smoke exposure, the baseline CBF was significantly decreased (2-3 Hz) versus control mice, and a β-agonist failed to stimulate increased CBF. The loss of β-agonist-increased CBF continued at 9 months and 12 months of smoke exposure, and the baseline CBF was significantly decreased to less than one third of the control rate. In addition to CBF, ciliated cell numbers significantly decreased in response to smoke over time, with a significant loss of tracheal ciliated cells occurring between 6 and 12 months. In parallel with the slowing of CBF, significant PKC activation from cytosol to the membrane of tracheal epithelial cells was detected in mice exposed to smoke for 6-12 months.

Changes in human bone marrow fat content associated with changes in hematopoietic stem cell numbers and cytokine levels with aging

Hematological deficiencies increase with aging, including anemias, reduced responses to hematopoietic stress and myelodysplasias. This investigation tested the hypothesis that increased bone marrow (BM) fat content in humans with age was associated with decreased numbers of side population (SP) hematopoietic stem cells, and this decrease correlated with changes in cytokine levels. BM was obtained from the femoral head and trochanteric region of the femur removed at surgery for total hip replacement (N = 100 subjects). In addition, BM from cadavers (N = 36), with no evidence of hip disease, was evaluated for fat content. Whole trabecular marrow samples were ground in a sterile mortar and pestle, and cellularity and lipid content determined. Marrow cells were stained with Hoechst dye and SP profiles were acquired. Plasma levels of insulin‐like growth factor (IGF)‐1, stromal‐derived factor (SDF)‐1 and interleukin (IL)‐6 were measured using ELISA. Fat content in the BM of human subjects and cadavers increased with age. The numbers of SP stem cells in BM as well as plasma IGF‐1 and SDF‐1 levels decreased in correlation with increased BM fat. IL‐6 had no relationship to changes in marrow fat. These data suggest that increased BM fat may be associated with a decreased number of SP stem cells and IGF‐1 and SDF‐1 levels with aging. These data further raise a more general question as to the role of adipose cells in the regulation of tissue stem cells.

Non Cell-Autonomous Reprogramming of Adult Ocular Progenitors: Generation of Pluripotent Stem Cells without Exogenous Transcription Factors†‡§

Direct reprogramming of differentiated cells to induced pluripotent stem (iPS) cells by ectopic expression of defined transcription factors (TFs) represents a significant breakthrough towards the use of stem cells in regenerative medicine (Takahashi and Yamanaka Cell 2006;126:663–676). However, the virus‐mediated expression of exogenous transcription factors could be potentially harmful and, therefore, represents a barrier to the clinical use of iPS cells. Several approaches, ranging from plasmid‐mediated TF expression to introduction of recombinant TFs (Yamanaka Cell 2009;137:13–17; Zhou, Wu, Joo et al. Cell Stem Cell 2009;4:381–384), have been reported to address the risk associated with viral integration. We describe an alternative strategy of reprogramming somatic progenitors entirely through the recruitment of endogenous genes without the introduction of genetic materials or exogenous factors. To this end, we reprogrammed accessible and renewable progenitors from the limbal epithelium of adult rat eye by microenvironment‐based induction of endogenous iPS cell genes. Non cell‐autonomous reprogramming generates cells that are pluripotent and capable of differentiating into functional neurons, cardiomyocytes, and hepatocytes, which may facilitate autologous cell therapy to treat degenerative diseases. STEM CELLS 2009;27:3053–3060

Human blood and marrow side population stem cell and Stro-1 positive bone marrow stromal cell numbers decline with age, with an increase in quality of surviving stem cells: Correlation with cytokines

Hematological deficiencies increase with aging leading to anemias, reduced hematopoietic stress responses and myelodysplasias. This study tested the hypothesis that side population hematopoietic stem cells (SP-HSC) would decrease with aging, correlating with IGF-1 and IL-6 levels and increases in bone marrow fat. Marrow was obtained from the femoral head and trochanteric region of the femur at surgery for total hip replacement (N=100). Whole trabecular marrow samples were ground in a sterile mortar and pestle and cellularity and fat content determined. Marrow and blood mononuclear cells were stained with Hoechst dye and the SP-HSC profiles acquired. Marrow stromal cells (MSC) were enumerated flow cytometrically employing the Stro-1 antibody, and clonally in the colony forming unit fibroblast (CFU-F) assay. Plasma levels of IGF-1 (ng/ml) and IL-6 (pg/ml) were measured by ELISA. SP-HSC in blood and bone marrow decreased with age but the quality of the surviving stem cells increased. MSC decreased non-significantly. IGF-1 levels (mean=30.7, SEM=2) decreased and IL-6 levels (mean=4.4, SEM=1) increased with age as did marrow fat (mean=1.2mmfat/g, SEM=0.04). There were no significant correlations between cytokine levels or fat and SP-HSC numbers. Stem cells appear to be progressively lost with aging and only the highest quality stem cells survive.

Stimulation of neomucosal growth by systemic urogastrone

Patching small intestinal defects with colon serosa results in the growth of functional neomucosa. However, the rate of neomucosal growth is slow and the defect contracts markedly. The aim of this study was to determine if systemic urogastrone would enhance neomucosal growth. Twenty-two New Zealand white rabbits had two 2 X 5-cm ileal defects patched with colon serosa and osmotic pumps placed subcutaneously. Eleven animals had saline infused at a rate of 5 microliter/hr. The other eleven rabbits had urogastrone (1 mg/ml saline) infused at the same rate. One animal died in this group. There was a modest increase in neomucosal growth after 2 weeks of urogastrone infusion. Three weeks after patching, defect coverage was significantly greater in the urogastrone group (99.8 +/- 0.1 vs 96.0 +/- 1.2%, P less than 0.005) and more defects were completely covered by neomucosa (6/10 vs 1/12, P less than 0.05). Less contraction occurred in the urogastrone group (46 +/- 2 vs 35 +/- 3% initial defect, P less than 0.005) and resultant neomucosal surface area was greater (361 +/- 12 vs 266 +/- 20 mm2, P less than 0.0005). In vitro glucose uptake was significantly greater in the urogastrone group but disaccharidase and diamine oxidase activity were similar. Crypt cell production rate was significantly greater 2 weeks after operation compared to 3 weeks in both groups and was greater in the urogastrone group compared to the saline group at 2 weeks (24.9 +/- 1.1 vs 20.1 +/- 1.1, P less than 0.02). Systemic urogastrone enhances neomucosal growth by increasing the rate of growth and diminishing contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of intestinal regeneration: New insights

Intestinal regeneration is the process by which intestinal injury penetrating deep to the lamina propria heals. The regenerative process involves epithelial cell migration and proliferation, changes in cellular function, adaptation of subepithelial tissues, and contraction of the injured area. This requires interaction of multiple cell types. While many observations have been made about the process of regeneration, its regulation is not well understood. Previous studies, performed primarily in a serosal patch model, have identified many potential regulatory factors. These include location and size of the injury, other associated injury, e.g., resection, and a variety of agents that influence one or more of the primary processes involved. Epidermal growth factor (EGF), in particular, appears to play a role in many aspects of regeneration. Recent advances in the understanding of intestinal growth regulation have provided new insights into the regulation of intestinal regeneration. Developmental studies in genetically manipulated mice suggest a role for gene products not previously implicated in regeneration. The importance of apoptosis in growth regulation has recently been emphasized. Mesenchymal‐epithelial interactions have gained greater appreciation. Finally, it has become clear that immune cells and cytokines are important factors in this process. Transforming growth factor‐beta (TGFβ) has been implicated as another important regulator of several of the processes involved in intestinal regulation. Improved understanding of the regulation of intestinal regeneration will lead to new therapeutic approaches to stimulate intestinal healing in the clinical setting. Microsc. Res. Tech. 51:129–137, 2000.