Anti-cancer effects of metformin in a 3D co-culture model of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) presents with condensed stroma that contributes to its high invasive capability. Although metformin adjuvant treatment has been suggested to improve the survival times of patients with PDAC, the mechanism responsible for that benefit has been investigated only in two-dimensional cell lines. We assessed the anti-cancer effect of metformin in a three-dimensional (3D) co-culture model to quantify the migration behavior of patient-derived PDAC organoids and primary pancreatic stellate cells (PSCs). At a concentration of 10 μM, metformin reduced the migratory ability of the PSCs by downregulating the expression of matrix metalloproteinase-2 (MMP2). In the 3D direct co-cultivation of PDAC organoids and PSCs, metformin attenuated the transcription of cancer stemness-related genes. The reduced stromal migratory ability of PSCs was associated with the downregulation of MMP2, and MMP2 knockdown in PSCs reproduced their attenuated migratory ability. The anti-migration effect of a clinically relevant concentration of metformin was demonstrable in a 3D indirect co-culture model of PDAC consisting of patient-derived PDAC organoids and primary human PSCs. The metformin suppressed PSC migration via MMP2 downregulation and attenuated cancer stemness factors. Furthermore, oral administration of metformin (30 mg/kg) strikingly suppressed the growth of PDAC organoids xenograft in immunosuppressed mice. These results indicate metformin could offer the potential approach as an effective therapeutic drug for PDAC.

Protective effect of a novel clinical-grade small molecule necrosis inhibitor against oxidative stress and inflammation during islet transplantation

Inhibition of mitochondrial reactive oxygen species (ROS) and subsequent damage-associated molecular patterns (DAMPs)-induced inflammatory responses could be a novel target in clinical islet transplantation. We investigated the protective effects of NecroX-7, a novel clinical-grade necrosis inhibitor that specifically targets mitochondrial ROS, against primary islet graft failure. Islets from heterozygote human islet amyloid polypeptide transgenic (hIAPP^+/- ) mice and nonhuman primates (NHPs) were isolated or cultured with or without NecroX-7 in serum-deprived medium. Supplementation with NecroX-7 during hIAPP^+/- mouse islet isolation markedly increased islet viability and adenosine triphosphate content, and attenuated ROS, transcription of c-Jun N-terminal kinases, high mobility group box 1, interleukin-1beta (IL-1 β ), IL-6, and tumor necrosis factor-alpha. Supplementation of NecroX-7 during serum-deprived culture also protected hIAPP^+/- mouse and NHP islets against impaired viability, serum deprivation-induced ROS, proinflammatory response, and accumulation of toxic IAPP oligomer. Supplementation with NecroX-7 during isolation or serum-deprived culture of hIAPP^+/- mouse and NHP islets also improved posttransplant glycemia in the recipient streptozotocin-induced diabetic hIAPP^-/- mice and BALB/c-nu/nu mice, respectively. In conclusion, pretransplant administration of NecroX-7 during islet isolation and serum-deprived culture suppressed mitochondrial ROS injury, generation of DAMPs-induced proinflammatory responses, and accumulation of toxic IAPP oligomers ex vivo, and improved posttransplant glycemia in vivo.

Multi-layer surface modification of pancreatic islets for magnetic resonance imaging using ferumoxytol

Ferumoxytol is the only clinically available ultrasmall superparamagnetic iron oxide. However, the labeling efficacy of islet magnetic resonance imaging (MRI) using ferumoxytol is not suitable for use in clinical pancreatic islet transplantation (PIT). We evaluated the feasibility of pancreatic islet MRI using ferumoxytol through multi-layer surface modification. A four-layer nanoshield with poly (ethylene) glycol (PEG, 2 layers), ferumoxytol, and heparin was formed on the pancreatic islets. We compared pancreatic islet function, viability, and labeling efficacy of control, ferumoxytol alone-labeled, heparin-PEGylated, and ferumoxytol-heparin-PEGylated islets. With optimization of the ferumoxytol concentration during the ferumoxytol-heparin-PEGylation process, the labeling contrast in ex vivo MRI of ferumoxytol-heparin-PEGylated pancreatic islets was stronger than that of pancreatic islets labeled with ferumoxytol alone, without decreasing ex vivo islet viability or function. In a syngeneic mouse renal subcapsular PIT model, heparin-PEGylation and ferumoxytol-heparin-PEGylation delayed the revascularization of pancreatic islet grafts but did not impair glucose tolerance or revascularization of pancreatic islet grafts four weeks post-transplantation. Pancreatic islet visibility after labeling was also confirmed in a syngeneic mouse intraportal PIT model and in preliminary analysis of a non-human primate intraportal PIT model. In conclusion, multi-layer islet surface modification is a promising option for pancreatic islet MRI in intraportal PIT.

A Subset of Paracrine Factors as Efficient Biomarkers for Predicting Vascular Regenerative Efficacy of Mesenchymal Stromal/Stem Cells

Mesenchymal stromal/stem cells (MSCs) have been developed as a promising source for cell-based therapies of ischemic disease. However, there are some hurdles in their clinical application such as poor cell engraftment and inconsistent stem cell potency. In this study, we sought to find biomarkers for predicting potency of MSCs for proangiogenic therapy to improve their beneficial effects. Large variations were observed in proangiogenic factor secretion profiles of conditioned media derived from nine different donor-derived Wharton's jelly (WJ)-derived MSCs and 8 factors among 55 angiogenesis-related factors were secreted at considerable levels. Two distinct WJ-MSCs that had the lowest or the highest secretion of these eight factors showed corresponding proangiogenic activities in in vitro angiogenesis assays. When four additional different donor-derived WJ-MSCs were further examined, proangiogenic activities in migration and tube formation of endothelial cells and in in vivo Matrigel plug assay were highly consistent with secretion levels of four major factors (angiogenin, interleukin-8, monocyte chemoattractant protein-1, and vascular endothelial growth factor). Such correlation was also observed in vascular regenerative effect in a mouse hind limb ischemia model. Blocking of these four factors by neutralizing antibodies or knockdown of them by siRNA treatment resulted in significant inhibition of proangiogenic activities of not only WJ-MSCs, but also bone marrow-derived MSCs. These results suggest that these four factors may represent efficient biomarkers for predicting vascular regenerative efficacy of MSCs. Stem Cells 2019;37:77-88.

Highly Angiogenic, Nonthrombogenic Bone Marrow Mononuclear Cell-Derived Spheroids in Intraportal Islet Transplantation

Highly angiogenic bone marrow mononuclear cell-derived spheroids (BM-spheroids), formed by selective proliferation of the CD31⁺CD14⁺CD34⁺ monocyte subset via three-dimensional (3D) culture, have had robust angiogenetic capacity in rodent syngeneic renal subcapsular islet transplantation. We wondered whether the efficacy of BM-spheroids could be demonstrated in clinically relevant intraportal islet transplantation models without increasing the risk of portal thrombosis. The thrombogenic potential of intraportally infused BM-spheroids was compared with that of mesenchymal stem cells (MSCs) and MSC-derived spheroids (MSC-spheroids). The angiogenic efficacy and persistence in portal sinusoids of BM-spheroids were examined in rodent syngeneic and primate allogeneic intraportal islet transplantation models. In contrast to MSCs and MSC-spheroids, intraportal infusion of BM-spheroids did not evoke portal thrombosis. BM-spheroids had robust angiogenetic capacity in both the rodent and primate intraportal islet transplantation models and improved posttransplant glycemic outcomes. MRI and intravital microscopy findings revealed the persistence of intraportally infused BM-spheroids in portal sinusoids. Intraportal cotransplantation of allogeneic islets with autologous BM-spheroids in nonhuman primates further confirmed the clinical feasibility of this approach. In conclusion, cotransplantation of BM-spheroids enhances intraportal islet transplantation outcome without portal thrombosis in mice and nonhuman primates. Generating BM-spheroids by 3D culture prevented the rapid migration and disappearance of intraportally infused therapeutic cells.

Anakinra Protects Against Serum Deprivation-Induced Inflammation and Functional Derangement in Islets Isolated From Nonhuman Primates

We investigated whether serum deprivation induces islet amyloid polypeptide (IAPP) oligomer accumulation and/or a proinflammatory response and, if so, whether the addition of interleukin (IL)-1 receptor antagonist to the culture medium can relieve the proinflammatory response during serum-deprived culture of nonhuman primate (NHP) islets. After culture in medium with and without Ana under serum-deprived culture conditions, IAPP oligomer/amyloid accumulation, in vitro viability, islet function, cytokine secretion, and posttransplantation outcome in streptozotocin-induced diabetic nude mice were determined in islets isolated from heterozygote human IAPP transgenic (hIAPP^+/- ) mice and/or NHP islets. Serum deprivation induced accumulation of IAPP oligomer, but not amyloid, in NHP islets. Anakinra (Ana) protected islets from the serum deprivation-induced impairment of in vitro viability and glucose-stimulated insulin secretion and attenuated serum deprivation-induced caspase-1 activation, transcription, and secretion of IL-1β, IL-6, and tumor necrosis factor-α in hIAPP^+/- mice and NHP islets. Supplementation of medium with Ana during serum-deprived culture also improved posttransplantation in vivo outcomes of NHP islets. In conclusion, serum deprivation induced accumulation of IAPP oligomers and proinflammatory responses in cultured isolated islets. Supplementation of the culture medium with Ana attenuated the functional impairment and proinflammatory responses induced by serum deprivation in ex vivo culture of NHP islets.

Tauroursodeoxycholic acid, a bile acid, promotes blood vessel repair by recruiting vasculogenic progenitor cells

Although serum bile acid concentrations are approximately 10 µM in healthy subjects, the crosstalk between the biliary system and vascular repair has never been investigated. In this study, tauroursodeoxycholic acid (TUDCA) induced dissociation of CD34(+) hematopoietic stem cells (HSCs) from stromal cells by reducing adhesion molecule expression. TUDCA increased CD34(+) /Sca1(+) progenitors in mice peripheral blood (PB), and CD34(+) , CD31(+) , and c-kit(+) progenitors in human PB. In addition, TUDCA increased differentiation of CD34(+) HSCs into EPC lineage cells via Akt activation. EPC invasion was increased by TUDCA, which was mediated by fibroblast activating protein via Akt activation. Interestingly, TUDCA induced integration of EPCs into human aortic endothelial cells (HAECs) by increasing adhesion molecule expression. In the mouse hind limb ischemia model, TUDCA promoted blood perfusion by enhancing angiogenesis through recruitment of Flk-1(+) /CD34(+) and Sca-1(+) /c-kit(+) progenitors into damaged tissue. In GFP(+) bone marrow-transplanted hind limb ischemia, TUDCA induced recruitment of GFP(+) /c-kit(+) progenitors to the ischemic area, resulting in an increased blood perfusion ratio. Histological analysis suggested that GFP(+) progenitors mobilized from bone marrow, integrated into blood vessels, and differentiated into VEGFR(+) cells. In addition, TUDCA decreased cellular senescence by reducing levels of p53, p21, and reactive oxygen species and increased nitric oxide. Transplantation of TUDCA-primed senescent EPCs in hind limb ischemia significantly improved blood vessel regeneration, as compared with senescent EPCs. Our results suggested that TUDCA promoted neovascularization by enhancing the mobilization of stem/progenitor cells from bone marrow, their differentiation into EPCs, and their integration with preexisting endothelial cells.

Improved revascularization of islet grafts using an angiogenic monocyte subpopulation derived from spheroid culture of bone marrow mononuclear cells

The spheroid culture method is an effective strategy for ex vivo expansion of an autologous therapeutic cell population. We investigated if cotransplantation of bone marrow-derived spheroids (BM-spheroid) formed using 3D culture of BM-derived mononuclear cells (BM-MNCs) could improve the posttransplant outcome of islet grafts using a mouse syngeneic marginal mass renal subcapsular islet transplantation model. Using green fluorescent protein transgenic (GFP-Tg) mice, the role of the BM-spheroids and the contribution of vessels derived from donors and recipients in grafted areas were assessed by immunohistochemistry. Compared to fresh BM-MNCs and nonspheroid remnant cells (BM-nonspheroid), the BM-spheroids, mainly composed of CXCR4(+) CD14(+) myeloid cells, showed higher angiogenic capacity, such as in vitro self-formed vessel structures; increased expression of angiogenic and chemoattractive factors; and incorporation into new vessel formation in basement membrane matrix plugs. BM-spheroid cotransplantation with islets improved the posttransplant outcomes in terms of glucose tolerance, serum insulin level, and diabetes reversal rate when compared with cotransplantation of BM-nonspheroids. Immunohistochemistry revealed that cotransplantation of the BM-spheroids increased vessel density, area of grafted endocrine and non-endocrine tissue, and β cell proliferation. In conclusion, cotransplantation of islets and BM-spheroids improved islet function through facilitation of revascularization and an increase in cell proliferation and islet cell mass.

Benefits of PEGylation in the early post-transplant period of intraportal islet transplantation as assessed by magnetic resonance imaging of labeled islets

While a few studies have demonstrated the benefit of PEGylation in islet transplantation, most have employed renal subcapsular models and none have performed direct comparisons of islet mass in intraportal islet transplantation using islet magnetic resonance imaging (MRI). In this study, our aim was to demonstrate the benefit of PEGylation in the early post-transplant period of intraportal islet transplantation with a novel algorithm for islet MRI. Islets were PEGylated after ferucarbotran labeling in a rat syngeneic intraportal islet transplantation model followed by comparisons of post-transplant glycemic levels in recipient rats infused with PEGylated (n = 12) and non-PEGylated (n = 13) islets. The total area of hypointense spots and the number of hypointense spots larger than 1.758 mm(2) of PEGylated and non-PEGylated islets were quantitatively compared. The total area of hypointense spots (P < 0.05) and the number of hypointense spots larger than 1.758 mm(2) (P < 0.05) were higher in the PEGylated islet group 7 and 14 days post translation (DPT). These results translated into better post-transplant outcomes in the PEGylated islet group 28 DPT. In validation experiments, MRI parameters obtained 1, 7, and 14 DPT predicted normoglycemia 4 wk post-transplantation. We directly demonstrated the benefit of islet PEGylation in protection against nonspecific islet destruction in the early post-transplant period of intraportal islet transplantation using a novel algorithm for islet MRI. This novel algorithm could serve as a useful tool to demonstrate such benefit in future clinical trials of islet transplantation using PEGylated islets.

Life-threatening methemoglobinemia after unintentional ingestion of antifreeze admixtures containing sodium nitrite in the construction sites

CONTEXT

Construction workers are exposed to a wide variety of health hazards such as poisoning at the construction sites. Various forms of poisoning incidents in construction workers have been reported. However, studies on methemoglobinemia caused by unintentional ingestion of antifreeze admixtures containing sodium nitrite at the construction sites have not been reported yet.

OBJECTIVE

The aim of this study was to evaluate life-threatening methemoglobinemia after unintentional ingestion of antifreeze admixtures containing sodium nitrite at the construction sites and describe similar incidents involving ingestion of antifreeze admixtures in Korea.

MATERIALS AND METHODS

Retrospective observational case series study on patients with methemoglobinemia after unintentional ingestion of antifreeze admixtures containing sodium nitrite admitted to the emergency department (ED) from January 1, 2010 to December 31, 2012 and cases reported to the Korea Occupational Safety and Health Agency (KOSHA) was performed. Results. Six victims were admitted to our ED. They had methemoglobin levels ranging from 32.4% to 71.5% and all of them recovered after receiving one (2 mg/kg) or two doses infusion of methylene blue. From the data of the KOSHA, six incidents that caused 27 victims were identified. Of 27 victims, five were included in the ED cases. For all incidents, antifreeze admixtures were not contained in their original containers and all new containers did not have a new label. All workers mistook antifreeze admixtures for water. Among the 28 victims included in this study, four died.

CONCLUSION

Unintentional ingestion of antifreeze admixtures containing sodium nitrite at the construction sites can cause life-threatening methemoglobinemia. There is a need to store and label potentially hazardous materials properly to avoid unintentional ingestion at the construction sites.

Reduced food intake is the major contributor to the protective effect of rimonabant on islet in established obesity-associated type 2 diabetes

PURPOSE

Although the presence of cannabinoid type 1 (CB1) receptor in islets has been reported, the major contributor to the protective effect of rimonabant on islet morphology is unknown. We determined whether the protective effect of rimonabant on pancreatic islet morphology is valid in established diabetes and also whether any effect was independent of decreased food intake.

MATERIALS AND METHODS

After diabetes was confirmed, Otsuka Long-Evans Tokushima Fatty rats, aged 32 weeks, were treated with rimonabant (30 mg/kg/d, rimonabant group) for 6 weeks. Metabolic profiles and islet morphology of rats treated with rimonabant were compared with those of controls without treatment (control group), a pair-fed control group, and rats treated with rosiglitazone (4 mg/kg/d, rosiglitazone group).

RESULTS

Compared to the control group, rats treated with rimonabant exhibited reduced glycated albumin levels (p<0.001), islet fibrosis (p<0.01), and improved glucose tolerance (p< 0.05), with no differences from the pair-fed control group. The retroperitoneal adipose tissue mass was lower in the rimonabant group than those of the pair-fed control and rosiglitazone groups (p<0.05). Rimonabant, pair-fed control, and rosiglitazone groups showed decreased insulin resistance and increased adiponectin, with no differences between the rimonabant and pair-fed control groups.

CONCLUSION

Rimonabant had a protective effect on islet morphology in vivo even in established diabetes. However, the protective effect was also reproduced by pair-feeding. Thus, the results of this study did not support the significance of islet CB1 receptors in islet protection with rimonabant in established obesity-associated type 2 diabetes.

Co-transplantation of bone marrow-derived endothelial progenitor cells improves revascularization and organization in islet grafts

Bone marrow-derived early endothelial progenitor cells (BM-EPCs) are a clinical tool for enhancing revascularization. However, the therapeutic efficacy of co-transplantation of BM-EPC with islets has not been investigated. In this study, marginal mass islets were co-transplanted with or without BM-EPCs under the kidney capsules of syngeneic streptozotocin-induced diabetic mice. Using green fluorescent protein transgenic (GFP-Tg) mice as BM-EPC and islet donors or recipients, the role of EPCs in revascularization was assessed for graft morphology, vascular density and fate of EPCs by immunohistochemistry. Islet-EPC co-transplantation improved the outcome of islet transplantation as measured by glucose tolerance, serum insulin level and diabetes reversal rate, compared with transplantation of islets alone. Between groups, the morphology of islet grafts showed significant differences in size and composition of grafted endocrine tissues. Significantly more vessel density derived from donors and recipients was detected with islet-EPC co-transplantation. Abundant GFP-Tg mice-derived BM-EPCs (GFP-EPCs) were observed in or around islet grafts and incorporated into CD31-positive capillaries. Remaining GFP-EPCs expressed VEGF. In conclusion, co-transplantation of islets with BM-EPCs could improve the outcome of marginal mass islet transplantation by promoting revascularization and preserving islet morphology.

A case of severe methemoglobinemia caused by hair dye poisoning

Context:

Hair dyes are widely used and very popular xenobiotics. Most of these products contain paraphenylenediamine (PPD) that can cause methemoglobinemia. We here report a case of severe methemoglobinemia that we treated using large amounts of methylene blue.

Case details:

A 30-year-old man visited a regional hospital with cyanosis. He was congenitally blind and had autism. For several weeks, he had mistaken hair dye for toothpaste. When he arrived at a regional hospital, he was drowsy with cyanosis and his initial serum methemoglobin (MetHb) level was 59.5%. After being treated with 2 mg/kg methylene blue (1 mg/kg × 2 administrations), he was transferred to a tertiary university hospital. Upon presentation at the Emergency Department in the tertiary hospital, his MetHb level was found to be 49.4% and his oxygen saturation was 80%. He was then admitted to the intensive care unit. After treatment with 4 mg/kg methylene blue (1 mg/kg × 4 administrations), he successfully recovered.

Discussion:

Because PPD can result in serious methemoglobinemia, clinicians should test it in cyanotic patients who have been exposed to hair dye for an extended period.

Intracardiac thrombus formation induced by carbon monoxide poisoning

INTRODUCTION

Carbon monoxide (CO) is one of the leading causes of poisoning; it inhibits oxygen delivery, subsequently causing ischemic changes and ultimately death by multiorgan failure. Furthermore, thromboembolic episodes due to CO poisoning have been reported. However, intracardiac thrombus formation following exposure to CO has been very rarely described. Here, a case of right atrial large thrombus formation after CO poisoning is presented.

CASE PRESENTATION

A previously healthy 24-year-old woman was referred for CO poisoning. She has attempted suicide, and her initial mental status was drowsy with focal memory loss. Her initial CO fraction was 16%, and initial laboratory data showed creatinine kinase-myocardial bound of 90.6 ng/mL (upper limit 5 ng/mL) and troponin I of 1.899 ng/mL (upper limit 1.5 ng/mL). A transthoracic echocardiography was performed 24 h after the accident, revealing a 30 15 mm nodular echogenic mass in the right atrium. Anticoagulation with low-molecular-weight heparin was started along with hyperbaric oxygen therapy. After 7 days of heparinization, the large thrombus in right atrium had resolved.

CONCLUSION

This report describes an intracardiac thrombus formation induced by CO poisoning. Because intracardiac thrombus can result in pulmonary embolism and cerebral embolic infarction, its consideration following CO poisoning is important.

Counting small hypointense spots confounds the quantification of functional islet mass based on islet MRI

Iron-containing fragmented islets or free iron released from dying cells could confound the interpretation of MRI of iron nanoparticle-labeled islets. Exclusion of small hypointense spots could be a useful strategy to avoid such artifact. We investigated whether this strategy could improve the estimation of functioning islet mass after islet transplantation. Using a rat syngeneic intraportal islet transplantation model, we quantitatively assessed the relationships between total area, number of hypointense spots on MRI that belong to each size quartile and glycemic control of the recipients. The total area of hypointense spots on MRI was greater in the recipients that achieved diabetes reversal (p = 0.002), whereas the total number of hypointense spots was not different (p = 0.757). Exclusion of small hypointense spots improved the association between the number of hypointense spots and the blood glucose level of the recipients (p < 0.001). Ex-vivo imaging and histologic study confirmed that some small hypointense spots represent the phagocytosed free iron. Exclusion of small hypointense spots improved the quantification of the functional islet mass based on islet MRI. This would be a useful principle in the development of an algorithm to estimate functioning islet mass based on islet MRI.

Endothelial colony-forming cell coating of pig islets prevents xenogeneic instant blood-mediated inflammatory reaction

Instant blood-mediated inflammatory reaction (IBMIR) causes rapid islet loss in islet transplantation. Endothelial colony-forming cells (ECFCs) display unique abilities to promote angiogenesis and repair vascular injury compared to those of endothelial cells (ECs), which inhibits the allogeneic and xenogeneic IBMIR. We investigated the coating of pig islets with ex vivo-expanded ECFCs as a strategy to overcome xenogeneic IBMIR. Porcine islets were cocultured with human ECFCs in a specially modified culture medium for 2 days to obtain 70-90% coverage. The coating of pig islets with human ECFCs did not affect the glucose-stimulated insulin secretion capacity or diabetes reversal rate after the transplantation of a marginal islet mass under the kidney capsules of diabetic nude mice compared to that of untreated islets. Uncoated islets, PBS control without islets, and the ECFC-coated islets were examined with an in vitro tubing loop assay using human blood. After 60 min of incubation in human blood, the ECFC-coated islets showed platelet consumption inhibition and low C3a and TAT assay results compared to those of the uncoated islets. Furthermore, there was very little macroscopic or microscopic clotting in the human ECFC-coated pig islets. The protective effect was more prominent compared to that of human EC coating of pig islets in our previous study. We investigated the changes in human-specific MCP-1, IL-8, and tissue factor (TF) levels after the coating of pig islets with human ECFCs or human ECs. The IL-8 levels after coating pig islets with ECFCs were significantly lower than those after coating pig islets with ECs, but there were no significant differences in the MCP-1 or TF levels between the ECFCs and ECs. In conclusion, the coating of pig islets with ECFCs completely prevented all components of xenogeneic IBMIR. ECFCs may be a better source of protection against xenogeneic IBMIR than are mature ECs.

Differences in donor CXCR4 expression levels are correlated with functional capacity and therapeutic outcome of angiogenic treatment with endothelial colony forming cells

CXCR4 expression is important for cell migration and recruitment, suggesting that the expression levels of CXCR4 may be correlated with functional activity of implanted cells for therapeutic neovascularization. Here, we examined differences between umbilical cord blood (CB) donors in the CXCR4 levels of endothelial colony forming cells (ECFCs), which are a subtype of endothelial progenitor cells (EPCs). We investigated the relationships between CXCR4 expression level and SDF-1alpha-induced vascular properties in vitro, and their in vivo contributions to neovascularization. We found that ECFCs isolated from different donors showed differences in CXCR4 expression that were linearly correlated with SDF-1alpha-induced migratory capacity. ECFCs with high CXCR4 expression showed enhanced ERK and Akt activation in response to SDF-1alpha. In addition, SDF-1alpha-induced migration and ERK1/2, Akt, and eNOS activation were reduced by AMD3100, a CXCR4-specific peptide antagonist, or by siRNA-CXCR4. Administration of high-CXCR4-expressing ECFCs resulted in a significant increase in therapeutic potential for blood flow recovery, tissue healing and capillary density compared to low-CXCR4-expressing ECFCs in hindlimb ischemia. Taken together, the functional differences among ECFCs derived from different donors depended on the level of CXCR4 expression, suggesting that CXCR4 expression levels in ECFCs could be a predictive marker for success of ECFC-based angiogenic therapy.

Simultaneous sternothoracic cardiopulmonary resuscitation: a new method of cardiopulmonary resuscitation

No existing device for cardiopulmonary resuscitation (CPR) is designed to exploit both the "cardiac pump" and the "thoracic pump" effect simultaneously. The purpose of this study was to measure the haemodynamic effect of a new simultaneous sternothoracic cardiopulmonary resuscitation (SST-CPR) device that could compress the sternum and constrict the thoracic cavity simultaneously in a canine cardiac arrest model. After 4 min of ventricular fibrillation, 24 mongrel dogs were randomized to receive standard CPR (n=12) or SST-CPR (n=12). SST-CPR generated a new pattern of the aortic pressure curve presumed to be the result of both sternal compression and thoracic constriction. SST-CPR resulted in significantly higher mean arterial pressure than standard CPR (68.9+/-16.1 vs. 30.5+/-10.0 mmHg, P<0.01). SST-CPR generated higher coronary perfusion pressure than standard CPR (47.0+/-11.4 vs. 17.3+/-8.9 mmHg, P<0.01). End tidal CO(2) tension was also higher during SST-CPR than standard CPR (11.6+/-6.1 vs. 2.17+/-3.3 mmHg, P<0.01). In this preliminary animal model study, simultaneous sternothoracic cardiopulmonary resuscitation generated better haemodynamic effects than standard, closed chest cardiopulmonary resuscitation.

Inhibition of fungal appressorium formation by pepper (Capsicum annuum) esterase

A pepper esterase gene (PepEST) that is highly expressed during an incompatible interaction between pepper (Capsicum annuum) and the anthracnose fungus Colletotrichum gloeosporioides has been previously cloned. Glutathione-S-transferase-tagged recombinant PepEST protein expressed in Escherichia coli showed substrate specificity for p-nitrophenyl esters. Inoculation of compatible unripe pepper fruits with C. gloeosporioides spores amended with the recombinant protein did not cause anthracnose symptoms on the fruit. The recombinant protein has no fungicidal activity, but it significantly inhibits appressorium formation of the anthracnose fungus in a dose-dependent manner. An esterase from porcine liver also inhibited appressorium formation, and the recombinant protein inhibited appressorium formation in the rice blast fungus, Magnaporthe grisea. Inhibition of appressorium formation in M. grisea by the recombinant protein was reversible by treatment with cyclic AMP (cAMP) or 1,16-hexadecanediol. The results suggest that the recombinant protein regulates appressorium formation by modulating the cAMP-dependent signaling pathway in this fungus. Taken together, the PepEST esterase activity can inhibit appressorium formation of C. gloeosporioides, which may result in protection of the unripe fruit against the fungus.

A cytochrome P450 gene is differentially expressed in compatible and incompatible interactions between pepper (Capsicum annuum) and the anthracnose fungus, Colletotrichum gloeosporioides

The anthracnose fungus, Colletotrichum gloeosporioides, was previously shown to have an incompatible interaction with ripe-red fruit of pepper (Capsicum annuum). However, the fungus had a compatible interaction with unripe-mature-green fruit. Using mRNA differential display, we isolated and characterized a PepCYP gene expressed in the incompatible interaction. The PepCYP gene encodes a protein homologous to cytochrome P450 proteins containing a heme-binding domain. The expression level of PepCYP is higher in the incompatible interaction than in the compatible interaction, and then remains elevated in the incompatible interaction. In the compatible interaction, the expression of PepCYP is transient. The induction of PepCYP gene is up-regulated by wounding or jasmonic acid treatment during ripening. Analysis of PepCYP expression by in situ hybridization shows that the accumulation of PepCYP mRNA is localized in the epidermal cell layers, but not in the cortical cell layers. An examination of transverse sections of the fruits inoculated with the fungus shows that the fungus invades and colonizes the epidermal cell layers of the unripe fruit at 24 and 72 h after inoculation, respectively, but not those of the ripe fruit. These results suggest that the PepCYP gene product plays a role in the defense mechanism when the fungus invades and colonizes the epidermal cells of fruits in the incompatible interaction during the early fungal infection process.

Induction of early flowering in Cymbidium niveo-marginatum Mak in vitro

 Many orchids take several years to flower. We have been able to induce early flowering in the temperate orchid Cymbidium niveo-marginatum Mak in vitro. The combined treatment of cytokinin (6-benzylaminopurine), restricted nitrogen supply with phosphorus enrichment, and root excision (pruning) induced transition of the Cymbidium shoot from a vegetative to a reproductive stage. Nearly 100% of the plants flowered within 90 days only when the combined treatment was applied. When root excision and/or 6-benzylaminopurine were omitted from the combined treatments, flower induction was significantly reduced. The auxin transport inhibitor, 2,3,5-triiodobenzoic acid prevented flowering of Cymbidium in vitro, although auxin (α-naphthaleneacetic acid) itself did not induce flowering. Gibberellic acid markedly delayed flowering in C. niveo-marginatum even when the flower-promoting treatment was applied. Paclobutrazol, an anti-gibberellin agent, totally blocked the inductive effects of either cytokinin or pruning. These observations suggest that concerted actions of auxin, cytokinin, and gibberellin, as well as nutrient concentration and putative promoting/suppressing agents, determine the timing of Cymbidium orchid transition from the vegetative to reproductive stage.

Coexpression of a defensin gene and a thionin-like via different signal transduction pathways in pepper and Colletotrichum gloeosporioides interactions

The anthracnose fungus, Colletotrichum gloeosporioides, interacts incompatibly with the ripe fruit of pepper (Capsicum annuum). It interacts compatibly with the unripe-mature fruit. We isolated a defensin gene, jl-l, and a thionin-like gene, PepThi, expressed in the incompatible interaction by using an mRNA differential display method. Both genes were developmentally regulated during fruit ripening, organ-specifically regulated, and differentially induced during the compatible and incompatible interactions. Expression of the PepThi gene was rapidly induced in the incompatible-ripe fruit upon fungal infection. The fungus-inducible PepThi gene is highly inducible only in the unripe fruit by salicylic acid. In both ripe and unripe fruit, it was induced by wounding, but not by jasmonic acid. Expression of the jl-l gene is enhanced by jasmonic acid in the unripe fruit but suppressed in the ripe fruit. These results suggest that both small and cysteine-rich protein genes are induced via different signal transduction pathways during fruit ripening to protect the reproductive organs against biotic and abiotic stresses.

Isolation and characterization of a cDNA encoding the cysteine proteinase inhibitor, induced upon flower maturation in carnation using suppression subtractive hybridization

The suppression subtractive hybridization (SSH) method was used to isolate differentially expressed genes during carnation flower maturation. Five cDNA clones, designated as carnation flower maturation-induced (CFMI), were verified as flower maturation-induced cDNAs. Sequence analysis of five CFMI (CFMI-5, CFMI-6, CFMI-7, CFMI-9, and CFMI-10) clones revealed that one of the clones, CFMI-5, showed high sequence similarity to the cysteine proteinase inhibitor gene, predicted to be involved in flower maturation. The full length cDNA clone CFMI-5 was 531 nucleotides (nts) long and consisted of an open reading frame of 294 nucleotides, encoding a 98 amino acid protein, 12 nucleotides of 5'-untranslated region and 3'-untranslated region (225 nts) with a poly(A)+ tail. The predicted CFMI-5 amino acid sequence had a conserved sequence Gln-Val-Val-Ala-Gly, which corresponds to the active site of proteinase inhibition. Northern blot analysis revealed tissue-specific expression of CFMI-5 transcripts, as the transcripts were expressed preferentially in petals and styles. A PCR-based cDNA subtraction method, termed suppression subtractive hybridization, was identified as a rapid method to screen differentially expressed genes in a short time.

Cymbidium hybrida dihydroflavonol 4-reductase does not efficiently reduce dihydrokaempferol to produce orange pelargonidin-type anthocyanins

Some angiosperms are limited to a range of possible flower colors. This limitation can be due to the lack of an anthocyanin biosynthetic gene or to the substrate specificity of a key anthocyanin biosynthetic enzyme, dihydroflavonol 4-reductase (DFR). Cymbidium hybrida orchid flowers primarily produce cyanidin-type (pink to red) anthocyanins and lack the pelargonidin-type (orange to brick-red) anthocyanins. To investigate the underlying molecular mechanism of this flower color range, we cloned a Cymbidium DFR gene and transformed it into a DFR- petunia line. We found that the Cymbidium DFR did not efficiently reduce dihydrokaempferol (DHK), which is an essential step for pelargonidin production. Phylogenetic analysis of a number of DFR sequences indicate that the inability to catalyze DHK reduction has occurred at least twice during angiosperm evolution. Our results indicate that developing a pelargonidin-type orange flower color in Cymbidium may require the transformation of a DFR gene that can efficiently catalyze DHK reduction.

Nonalcoholic steatohepatitis: Mayo Clinic experiences with a hitherto unnamed disease

Nonalcoholic steatohepatitis is a poorly understood and hitherto unnamed liver disease that histologically mimics alcoholic hepatitis and that also may progress to cirrhosis. Described here are findings in 20 patients with nonalcoholic steatohepatitis of unknown cause. The biopsy specimens were characterized by the presence of striking fatty changes with evidence of lobular hepatitis, focal necroses with mixed inflammatory infiltrates, and, in most instances, Mallory bodies; Evidence of fibrosis was found in most specimens, and cirrhosis was diagnosed in biopsy tissue from three patients. The disease was more common in women. Most patients were moderately obese, and many had obesity-associated diseases, such as diabetes mellitus and cholelithiasis. Presence of hepatomegaly and mild abnormalities of liver function were common clinical findings. Currently, we know of no effective therapy.