Multipotential stem cells can be selected from the bone marrow by plastic adhesion, expanded, and cultured. They are able to differentiate not only into multiple cell types, including cartilage, ...bone, adipose and fibrous tissues, and myelosupportive stroma, but also into mesodermal (endothelium), neuroectodermal, or endodermal (hepatocytes) lineages. Our goal was to characterize the multipotential capacities of human mesenchymal stem cells (hMSCs) and to evaluate their ability to differentiate into insulin‐secreting cells in vitro. hMSCs were obtained from healthy donors, selected by plastic adhesion, and phenotyped by fluorescence‐activated cell sorter and reverse transcription–polymerase chain reaction analysis before and after infection with adenoviruses coding for mouse IPF1, HLXB9, and FOXA2 transcription factors involved early in the endocrine developmental pathway. We found that native hMSCs have a pluripotent phenotype (OCT4 expression and high telomere length) and constitutively express NKX6‐1 at a low level but lack all other transcription factors implicated in beta‐cell differentiation. In all hMSCs, we detected mRNA of cytokeratin 18 and 19, epithelial markers present in pancreatic ductal cells, whereas proconvertase 1/3 mRNA expression was detected only in some hMSCs. Ectopic expression of IPF1, HLXB9, and FOXA2 with or without islet coculture or islet‐conditioned medium results in insulin gene expression. In conclusion, our results demonstrated that in vitro human bone marrow stem cells are able to differentiate into insulin‐expressing cells by a mechanism involving several transcription factors of the beta‐cell developmental pathway when cultured in an appropriate microenvironment.
Flavescence dorée (FD) is a threat for wine production in the vineyard landscape of Piemonte, Langhe-Roero and Monferrato, Italy. Spread of the disease is dependent on complex interactions between ...insect, plant and phytoplasma. In the Piemonte region, wine production is based on local cultivars. The role of six local grapevine varieties as a source of inoculum for the vector Scaphoideus titanus was investigated. FD phytoplasma (FDP) load was compared among red and white varieties with different susceptibility to FD. Laboratory-reared healthy S. titanus nymphs were caged for acquisition on infected plants to measure phytoplasma acquisition efficiency following feeding on different cultivars. FDP load for Arneis was significantly lower than for other varieties. Acquisition efficiency depended on grapevine variety and on FDP load in the source plants, and there was a positive interaction for acquisition between variety and phytoplasma load. S. titanus acquired FDP with high efficiency from the most susceptible varieties, suggesting that disease diffusion correlates more with vector acquisition efficiency than with FDP load in source grapevines. In conclusion, although acquisition efficiency depends on grapevine variety and on FDP load in the plant, even varieties supporting low FDP multiplication can be highly susceptible and good sources for vector infection, while poorly susceptible varieties may host high phytoplasma loads.
Multipotent mesenchymal stromal cells (MSC) are currently investigated clinically as cellular therapy for a variety of diseases. Differentiation of MSC toward endodermal lineages, including ...hepatocytes and their therapeutic effect on fibrosis has been described but remains controversial. Recent evidence attributed a fibrotic potential to MSC. As differentiation potential might be dependent of donor age, we studied MSC derived from adult and pediatric human bone marrow and their potential to differentiate into hepatocytes or myofibroblasts in vitro and in vivo. Following characterization, expanded adult and pediatric MSC were co-cultured with a human hepatoma cell line, Huh-7, in a hepatogenic differentiation medium containing Hepatocyte growth factor, Fibroblast growth factor 4 and oncostatin M. In vivo, MSC were transplanted into spleen or liver of NOD/SCID mice undergoing partial hepatectomy and retrorsine treatment. Expression of mesenchymal and hepatic markers was analyzed by RT-PCR, Western blot and immunohistochemistry. In vitro, adult and pediatric MSC expressed characteristic surface antigens of MSC. Expansion capacity of pediatric MSC was significantly higher when compared to adult MSC. In co-culture with Huh-7 cells in hepatogenic differentiation medium, albumin expression was more frequently detected in pediatric MSC (5/8 experiments) when compared to adult MSC (2/10 experiments). However, in such condition pediatric MSC expressed alpha smooth muscle more strongly than adult MSC. Stable engraftment in the liver was not achieved after intrasplenic injection of pediatric or adult MSC. After intrahepatic injection, MSC permanently remained in liver tissue, kept a mesenchymal morphology and expressed vimentin and alpha smooth muscle actin, but no hepatic markers. Further, MSC localization merges with collagen deposition in transplanted liver and no difference was observed using adult or pediatric MSC. In conclusion, when transplanted into an injured or regenerating liver, MSC differentiated into myofibroblasts with development of fibrous tissue, regardless of donor age. These results indicate that MSC in certain circumstances might be harmful due to their fibrogenic potential and this should be considered before potential use of MSC for cell therapy.
Type 1 diabetes (T1DM) results from destruction of most insulin-secreting pancreatic β-cells. The persistence of β-cells decades after the onset of the disease indicates that the resistance of ...individual cells to the autoimmune insult is heterogeneous and might depend on the metabolic status of a cell at a given moment. The aim of this study is to investigate whether activation of nicotinic acetylcholine receptors (nACh-Rs) could increase β-cell resistance against the adverse environment prevailing at the onset of T1DM. Here, we show that nACh-R activation by nicotine and choline, 2 agonists of the receptor, decreases murine and human β-cell apoptosis induced by proinflammatory cytokines known to be present in the islet environment at the onset of T1DM. The protective mechanism activated by nicotine and choline involves attenuation of mitochondrial outer membrane permeabilization via modulation of endoplasmic reticulum stress, of the activity of B-cell lymphoma 2 family proteins and cytoplasmic calcium levels. Local inflammation and endoplasmic reticulum stress being key determinants of β-cell death in T1DM, we conclude that pharmacological activation of nACh-R could represent a valuable therapeutic option in the modulation of β-cell death in T1DM.
Quantitative estimates of vector populations and their infectivity in the wild and in cultivated compartments of agroecosystems have been carried out to elucidate the role of the wild compartment in ...the epidemiology of Flavescence dorée (FD). Seven sites were selected for the investigations in the Piedmont Region of Italy. They were characterized by a high variety of agricultural and ecological landscape features, and included a vineyard surrounded by wild vegetation. In order to describe abundance and prevalence of FD-infected vectors in the cultivated and wild compartments of the vineyard agroecosystem, adults of
were collected by yellow sticky traps inside and outside the vineyard over the period July 10th-September 9th, 2015. They were counted and singly analyzed for the presence of FD phytoplasmas by PCR. Multifactorial correlations among vector population level, prevalence of infected insects inside and outside the vineyards, disease prevalence in cultivated and wild
plants, and location of wild
plants with respect to the vineyard were analyzed. Abundance of
adults significantly decreased from the end of July onwards, particularly inside the vineyard (average range 22.7 ± 2.5 insects/trap). Percentage of FD-positive
was significantly higher outside the vineyard (up to 48% on average) compared to inside the vineyard (up to 34% on average), and increased during the season in both compartments.
High concentrations of glucose induce β cell production of IL-1β, leading to impaired β cell function and apoptosis in human pancreatic islets. IL-1 receptor antagonist (IL-1Ra) is a naturally ...occurring antagonist of IL-1β and protects cultured human islets from glucotoxicity. Therefore, the balance of IL-1β and IL-1Ra may play a crucial role in the pathogenesis of diabetes. In the present study, we observed expression of IL-1Ra in human pancreatic β cells of nondiabetic individuals, which was decreased in tissue sections of type 2 diabetic patients. In vitro, chronic exposure of human islets to leptin, a hormone secreted by adipocytes, decreased β cell production of IL-1Ra and induced IL-1β release from the islet preparation, leading to impaired β cell function, caspase-3 activation, and apoptosis. Exogenous addition of IL-1Ra protected cultured human islets from the deleterious effects of leptin. Antagonizing IL-1Ra by introduction of small interfering RNA to IL-1Ra into human islets led to caspase-3 activation, DNA fragmentation, and impaired β cell function. Moreover, siIL-1Ra enhanced glucose-induced β cell apoptosis. These findings demonstrate expression of IL-1Ra in the human β cell, providing localized protection against leptin- and glucose-induced islet IL-1β.
This article delves into Blaise Pascal’s religious philosophy, focusing on his use of the phrase “Scio cui credidi” (I know whom I have believed) to explore his understanding of faith. It analyzes ...Pascal’s “Memorial” and the “Summary of the Life of Jesus Christ”, highlighting how Christ is central to Pascal’s belief system. The discussion reveals the transformational nature of Pascal’s faith, particularly after his mystical experience on November 23, 1654. This experience is crucial in understanding his shift from a philosophical to a deeply personal, Christ-centered faith. The article underscores Pascal’s journey from a scientific and philosophical perspective to an intimate, emotional resonance with Christian faith, demonstrating how his personal encounters with the divine profoundly shaped his religious perspective.
It has been suggested that the age of human organ donors might influence islet isolation and transplantation outcome in a negative way due to a decrease of in vivo function in islets isolated from ...older donors.
We retrospectively analyzed 332 islet isolations according to donor age. We determined isolation outcome by islet yields, transplantation rates, and beta-cell function in vitro. Transplanted patients were divided into two groups depending on donor age (n=25 and n=31 patients for <=45- and >45-year-old donors, respectively). We assessed islet graft function by C-peptide/glucose ratio, beta score, secretory units of islets in transplantation index, and insulin independence rate at 1, 6, and 12 months after transplantation.
There was no difference in islet yields between the two groups (251,900+/-14,100 and 244,600+/-8400 islet equivalent for <=45- and >45-year-old donors, respectively). Transplantation rates and stimulation indices were similar in both groups as well. All islet graft function parameters were significantly higher at 1-month follow-up in patients who had received islets from younger donors. At 6-month follow-up after second or third injection and at 12-month follow-up, secretory units of islets in transplantation indices and C-peptide/glucose ratios were significantly higher in patients with donors aged 45 years or younger.
These data suggest that, despite similar outcomes of the isolation procedure, islet graft function is significantly influenced by donor age. These results may have important consequences in the definition of pancreas allocation criteria.
Low Concentration of Interleukin-1β Induces FLICE-Inhibitory Protein–Mediated β-Cell Proliferation in Human Pancreatic Islets
Kathrin Maedler 1 ,
Desiree M. Schumann 2 ,
Nadine Sauter 2 ,
Helga ...Ellingsgaard 2 ,
Domenico Bosco 3 ,
Reto Baertschiger 3 ,
Yoichiro Iwakura 4 ,
José Oberholzer 5 ,
Claes B. Wollheim 6 ,
Benoit R. Gauthier 6 and
Marc Y. Donath 2
1 Larry L. Hillblom Islet Research Center, University of California, Los Angeles, California
2 Division of Endocrinology and Diabetes and Center for Integrative Human Physiology, University Hospital Zurich, Zurich, Switzerland
3 Department of Surgery, University Medical Center, Geneva, Switzerland
4 Center for Experimental Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan
5 Division of Transplantation, University of Illinois at Chicago, Chicago, Illinois
6 Department of Cell Physiology and Metabolism, University Medical Center, Geneva, Switzerland
Address correspondence and reprint requests to Marc Y. Donath, MD, Division of Endocrinology and Diabetes, Department of Medicine,
University Hospital, CH-8091 Zurich, Switzerland. E-mail: marc.donath{at}usz.ch
Abstract
High glucose concentrations have a dual effect on β-cell turnover, inducing proliferation in the short-term and apoptosis
in the long-term. Hyperglycemia leads to β-cell production of interleuking (IL)-1β in human pancreatic islets. Fas, a death
receptor regulated by IL-1β, is involved in glucose-induced β-cell apoptosis. Fas engagement can be switched from death signal
to induction of proliferation when the caspase 8 inhibitor, FLICE-inhibitory protein (FLIP), is active. Here, we show that
IL-1β at low concentrations may participate in the mitogenic actions of glucose through the Fas-FLIP pathway. Thus, exposure
of human islets to low IL-1β concentrations (0.01–0.02 ng/ml) stimulated proliferation and decreased apoptosis, whereas increasing
amounts of IL-1β (2–5 ng/ml) had the reverse effects. A similarly bimodal induction of FLIP, pancreatic duodenal homeobox
(PDX)-1, and Pax4 mRNA expression, as well as glucose-stimulated insulin secretion, was observed. In contrast, Fas induction
by IL-1β was monophasic. Low IL-1β also induced the IL-1 receptor antagonist (IL-1Ra), suppression of which by RNA interference
abrogated the beneficial effects of low IL-1β. The Fas antagonistic antibody ZB4 and small interfering RNA to FLIP prevented
low IL-1β–stimulated β-cell proliferation. Consistent with our in vitro results, IL-1β knockout mice displayed glucose intolerance
along with a decrease in islet Fas, FLIP, Pax4, and PDX-1 transcripts. These findings indicate that low IL-1β levels positively
influence β-cell function and turnover through the Fas-FLIP pathway and that IL-1Ra production prevents harmful effects of
high IL-1β concentrations.
FLIP, FLICE-inhibitory protein
GSIS, glucose-stimulated insulin secretion
IL, interleukin
IL-1Ra, IL-1 receptor antagonist
IRS, insulin receptor substrate
KRBB, Krebs-Ringer bicarbonate buffer
PDX, pancreatic duodenal homeobox
rh, recombinant human
siFLIP, siRNA directed to FLIP
siIL-1Ra, siRNA directed to IL-1Ra
siRNA, small interfering RNA
TUNEL, transferase-mediated dUTP nick-end labeling
Footnotes
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore
be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Accepted July 7, 2006.
Received November 2, 2005.
DIABETES
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