Marginal Mass Research Articles

Eastward shift and maintenance of Arabian Sea oxygen minimum zone: Understanding the paradox

The dominance of Oxygen Minimum Zone in the eastern part of the Arabian Sea (ASOMZ) instead of the more bio-productive and likely more oxygen consuming western part is the first part of the paradox. The sources of oxygen to the ASOMZ were evaluated through the distributions of different water masses using the extended optimum multiparameter (eOMP) analysis, whereas the sinks of oxygen were evaluated through the organic matter remineralization, using the apparent oxygen utilization (AOU). The contributions of major source waters to the Arabian Sea viz. Indian Deep water (dIDW), Indian Central water (ICW), Persian Gulf Water (PGW) and Red Sea Water (RSW) have been quantified through the eOMP analysis which shows that the PGW and RSW are significant for the eastward shift of ASOMZ instead of voluminous ICW and dIDW. The distribution of Net Primary Production (NPP) and AOU clearly suggest the transport of organic detritus from the highly productive western Arabian Sea to its eastern counterpart which adds to the eastward shifting of ASOMZ. A revised estimate of the seasonal variation of areal extent and volume occupied by ASOMZ through analysis of latest available data reveals a distinct intensification of ASOMZ by 30% and increase in its volume by 5% during the spring-summer transition. However, during this seasonal transition the productivity in the Arabian Sea shows 100% increase in mean NPP. This disparity between ASOMZ and monsoonal variation of productivity is the other part of the paradox, which has been constrained through apparent oxygen utilization, Net Primary Production along with a variation of core depths of source waters. This study reveals a subtle balance between the circulation of marginal oxygen-rich water masses from the western Arabian Sea and organic matter remineralization in the eastern Arabian Sea in different seasons that explains the maintenance of ASOMZ throughout the year.

Harnessing the Foreign Body Reaction in Marginal Mass Device-less Subcutaneous Islet Transplantation in Mice.

Islet transplantation is a successful β-cell replacement therapy for selected patients with type 1 diabetes mellitus. However, despite early insulin independence, long-term graft attrition gradually reverts recipients to exogenous insulin dependency. Undoubtedly, as insulin producing stem cell therapies progress, a transplant site that is retrievable is desirable. This prerequisite is currently incompatible with intrahepatic islet transplantation. Herein, we evaluate the functional capacity of a prevascularized subcutaneous site to accommodate marginal islet mass transplantation in mice. Syngeneic mouse islets (150) were transplanted either under the kidney capsule (KC), into a prevascularized subcutaneous device-less (DL) site, or into the unmodified subcutaneous (SC) tissue. The DL site was created 4 weeks before diabetes induction and islet transplantation through the transient placement of a 5-Fr vascular catheter. Recipient mice were monitored for glycemic control and intraperitoneal glucose tolerance. A marginal islet mass transplanted into the DL site routinely reversed diabetes (n = 13 of 18) whereas all SC islet recipients failed to restore glycemic control (n = 0 of 10, P < 0.01, log-rank). As anticipated, nearly all islet-KC mice (n = 15 of 16) became euglycemic posttransplant. The DL recipients' glucose profiles were comparable to KC islet grafts, postintrapertioneal glucose tolerance testing, whereas SC recipients remained hyperglycemic postglucose challenge. All normoglycemic mice maintained graft function for 100 days until graft retrieval. DL and KC islet grafts stained positively for insulin, microvessels, and a collagen scaffold. The device-less prevascularized approach supports marginal mass islet engraftment in mice.

A novel redox-active metalloporphyrin reduces reactive oxygen species and inflammatory markers but does not improve marginal mass engraftment in a murine donation after circulatory death islet transplantation model

ABSTRACTIslet transplantation is a highly effective treatment for stabilizing glycemic control for select patients with type-1 diabetes. Despite improvements to clinical transplantation, single-donor transplant success has been hard to achieve routinely, necessitating increasing demands on viable organ availability. Donation after circulatory death (DCD) may be an alternative option to increase organ availability however, these organs tend to be more compromised. The use of metalloporphyrin anti-inflammatory and antioxidant (MnP) compounds previously demonstrated improved in vivo islet function in preclinical islet transplantation. However, the administration of MnP (BMX-001) in a DCD islet isolation and transplantation model has yet to be established. In this study, murine donors were subjected to a 15-min warm ischemic (WI) period prior to isolation and culture with or without MnP. Subsequent to one-hour culture, islets were assessed for in vitro viability and in vivo function. A 15-minute WI period significantly reduced islet yield, regardless of MnP-treatment relative to yields from standard isolation. MnP-treated islets did not improve islet viability compared to DCD islets alone. MnP-treatment did significantly reduce the presence of extracellular reactive oxygen species (ROS) (p < 0 .05). Marginal, syngeneic islets (200 islets) transplanted under the renal capsule exhibited similar in vivo outcomes regardless of WI or MnP-treatment. DCD islet grafts harvested 7 d post-transplant exhibited sustained TNF-α and IL-10, while MnP-treated islet-bearing grafts demonstrated reduced IL-10 levels. Taken together, 15-minute WI in murine islet isolation significantly impairs islet yield. DCD islets do indeed demonstrate in vivo function, though MnP therapy was unable to improve viability and engraftment outcomes.

Red Ginseng Administration Before Islet Isolation Attenuates Apoptosis and Improves Islet Function and Transplant Outcome in a Syngeneic Mouse Marginal Islet Mass Model

BackgroundTransplantation of isolated islets is a promising treatment for diabetes. Red ginseng (RG) is steamed ginseng and has been reported to enhance insulin secretion–stimulating and anti-apoptotic activities in pancreatic β-cells. In this study, we examined the hypothesis that pre-operative RG treatment enhances islet cell function and anti-apoptosis and investigated whether RG improves islet engraftment by transplant of a marginal mass of syngeneic islets pretreated with RG in diabetic mice. MethodsBalb/c mice were randomly divided into 2 groups, and 1 group was administered RG (400 mg/kg/day orally) for 7 days before islet isolation. In vitro islet viability and function were assessed. After cytokine treatment, cell viability, function, and apoptosis of islet cells were analyzed. Furthermore, we studied the effects of RG in a syngeneic islet graft model. A marginal mass of syngeneic mouse islets was transplanted into diabetic hosts. ResultsIslet pretreatment with RG showed 1.4-fold higher glucose-induced insulin secretion than did control islets. RG pretreatment upregulated B-cell lymphoma 2 (Bcl-2) expression and downregulated Bcl-associated X protein (BAX), caspase-3, and inducible nitric oxide synthase (iNOS) expression. Glucose-induced insulin release, NO, and apoptosis were significantly improved in RG-pretreated islets compared with cytokine-treated islets. RG-pretreated mice exhibited improved marginal mass islet graft survival compared with controls. ConclusionsThese results suggest that pre-operative RG administration enhanced islet function before transplantation and attenuated cytokine-induced damage associated with apoptosis. These studies indicate that inhibition of apoptosis by RG significantly improved islet cell and graft function after isolation and transplantation, respectively.

Myt3 suppression sensitizes islet cells to high glucose-induced cell death via Bim induction.

Diabetes is a chronic disease that results from the body's inability to properly control circulating blood glucose levels. The loss of glucose homoeostasis can arise from a loss of β-cell mass because of immune-cell-mediated attack, as in type 1 diabetes, and/or from dysfunction of individual β-cells (in conjunction with target organ insulin resistance), as in type 2 diabetes. A better understanding of the transcriptional pathways regulating islet-cell survival is of great importance for the development of therapeutic strategies that target β-cells for diabetes. To this end, we previously identified the transcription factor Myt3 as a pro-survival factor in islets following acute suppression of Myt3 in vitro. To determine the effects of Myt3 suppression on islet-cell survival in vivo, we used an adenovirus to express an shRNA targeting Myt3 in syngeneic optimal and marginal mass islet transplants, and demonstrate that suppression of Myt3 impairs the function of marginal mass grafts. Analysis of grafts 5 weeks post-transplant revealed that grafts transduced with the shMyt3 adenovirus contained ~20% the number of transduced cells as grafts transduced with a control adenovirus. In fact, increased apoptosis and significant cell loss in the shMyt3-transduced grafts was evident after only 5 days, suggesting that Myt3 suppression sensitizes islet cells to stresses present in the early post-transplant period. Specifically, we find that Myt3 suppression sensitizes islet cells to high glucose-induced cell death via upregulation of the pro-apoptotic Bcl2 family member Bim. Taken together these data suggest that Myt3 may be an important link between glucotoxic and immune signalling pathways.

Distribution of polymer nanoparticles by convection-enhanced delivery to brain tumors

Glioblastoma multiforme (GBM) is a fatal brain tumor characterized by infiltration beyond the margins of the main tumor mass and local recurrence after surgery. The blood-brain barrier (BBB) poses the most significant hurdle to brain tumor treatment. Convection-enhanced delivery (CED) allows for local administration of agents, overcoming the restrictions of the BBB. Recently, polymer nanoparticles have been demonstrated to penetrate readily through the healthy brain when delivered by CED, and size has been shown to be a critical factor for nanoparticle penetration. Because these brain-penetrating nanoparticles (BPNPs) have high potential for treatment of intracranial tumors since they offer the potential for cell targeting and controlled drug release after administration, here we investigated the intratumoral CED infusions of PLGA BPNPs in animals bearing either U87 or RG2 intracranial tumors. We demonstrate that the overall volume of distribution of these BPNPs was similar to that observed in healthy brains; however, the presence of tumors resulted in asymmetric and heterogeneous distribution patterns, with substantial leakage into the peritumoral tissue. Together, our results suggest that CED of BPNPs should be optimized by accounting for tumor geometry, in terms of location, size and presence of necrotic regions, to determine the ideal infusion site and parameters for individual tumors.

Squamous Papilloma over Lid Margin: An Uncommon Presentation

ABSTRACT Papilloma is a histopathological term describing tumors of a classical finger-like or cauliflower morphology. Though benign, they carry profound malignancy potential and can present at numerous anatomical locations, such as skin, cervix, esophagus, respiratory tract, breast duct, etc. Papillomas over conjunctiva are not frequently encountered and carry special significance. A 60-year-old diabetic female presented with a left upper lid marginal sessile mass of 9 months duration with mild epiphora and foreign body sensation. On examination, a solitary, fleshy, sessile, polypoidal mass measuring 1 × 1 cm was seen, with irregular cauliflower-like surface present over lateral aspect of left upper lid, firm in consistency with raised edges. Visual acuity in right eye was 6/18→6/9 and left eye 6/36→6/9, intraocular pressure (IOP) was 14.6 mm Hg in both eyes by Schiotz tonometry. Complete excision of the lesion employing microsurgical technique with close apposition of lid margin using 6-0 Vicryl sutures was done under local anesthesia (LA). Histopathological examination revealed stratified squamous epithelium forming papillae with variable goblet cells supported by prominent branching fibrovascular cores in the center. A satisfactory cosmetic result was achieved. Follow-up of 6 months did not reveal any recurrence. A satisfactory functional and cosmetic result achieved. Squamous papillomas over lid margin are uncommon presentations. Even though benign they carry morbidity potential in the form of chronic epiphora, corneal erosions, and lid deformities if inadequately managed. How to cite this article Goyal E, Gupta P, Dokania A, Rizvi Y. Squamous Papilloma over Lid Margin: An Uncommon Presentation. Int J Adv Integ Med Sci 2016;1(3):128-130.

Diabetes Is Reversed in a Murine Model by Marginal Mass Syngeneic Islet Transplantation Using a Subcutaneous Cell Pouch Device.

BackgroundIslet transplantation is a successful β-cell replacement therapy for selected patients with type 1 diabetes mellitus. Although high rates of early insulin independence are achieved routinely, long-term function wanes over time. Intraportal transplantation is associated with procedural risks, requires multiple donors, and does not afford routine biopsy. Stem cell technologies may require potential for retrievability, and graft removal by hepatectomy is impractical. There is a clear clinical need for an alternative, optimized transplantation site. The subcutaneous space is a potential substitute, but transplantation of islets into this site has routinely failed to reverse diabetes. However, an implanted device, which becomes prevascularized before transplantation, may alter this equation.MethodsSyngeneic mouse islets were transplanted subcutaneously within Sernova Corp's Cell Pouch (CP). All recipients were preimplanted with CPs 4 weeks before diabetes induction and transplantation. After transplantation, recipients were monitored for glycemic control and glucose tolerance.ResultsMouse islets transplanted into the CP routinely restored glycemic control with modest delay and responded well to glucose challenge, comparable to renal subcapsular islet grafts, despite a marginal islet dose, and normoglycemia was maintained until graft explantation. In contrast, islets transplanted subcutaneously alone failed to engraft. Islets within CPs stained positively for insulin, glucagon, and microvessels.ConclusionsThe CP is biocompatible, forms an environment suitable for islet engraftment, and offers a potential alternative to the intraportal site for islet and future stem cell therapies.

Lixisenatide accelerates restoration of normoglycemia and improves human beta-cell function and survival in diabetic immunodeficient NOD-scid IL-2rg(null) RIP-DTR mice engrafted with human islets.

ObjectiveGlucagon-like peptide-1 induces glucose-dependent insulin secretion and, in rodents, increases proliferation and survival of pancreatic beta cells. To investigate the effects on human beta cells, we used immunodeficient mice transplanted with human islets. The goal was to determine whether lixisenatide, a glucagon-like peptide-1 receptor agonist, improves human islet function and survival in vivo.MethodsFive independent transplant studies were conducted with human islets from five individual donors. Diabetic human islet-engrafted immunodeficient mice were treated with lixisenatide (50, 150, and 500 µg/kg) or vehicle. Islet function was determined by blood glucose, plasma human insulin/C-peptide, and glucose tolerance tests. Grafts were analyzed for total beta- and alpha-cell number, percent proliferation, and levels of apoptosis.ResultsDiabetic mice transplanted with marginal human islet mass and treated with lixisenatide were restored to euglycemia more rapidly than vehicle-treated mice. Glucose tolerance tests, human plasma insulin, and glucose-stimulation indices of lixisenatide-treated mice were significantly improved compared to vehicle-treated mice. The percentages of proliferating or apoptotic beta cells at graft recovery were not different between lixisenatide-treated and vehicle-treated mice. Nevertheless, in one experiment we found a significant twofold to threefold increase in human beta-cell numbers in lixisenatide-treated compared to vehicle-treated mice.ConclusionDiabetic human islet-engrafted immunodeficient mice treated with lixisenatide show improved restoration of normoglycemia, human plasma insulin, and glucose tolerance compared to vehicle-treated mice engrafted with the same donor islets. Because the proliferative capacity of human beta cells is limited, improved beta-cell survival coupled with enhanced beta-cell function following lixisenatide treatment may provide the greatest benefit for diabetic patients with reduced functional islet mass.

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.

Morphometric Study of the Hypoglossal Nerve and the Hypoglossal Canal for the Surgery of the Upper Cervical Spine

Objective The upper cervical pathology is not an uncommon disease in the congenital anomaly, elderly population, and patients with rheumatoid. Newly developed operative techniques in high cervical region could be related to neurovascular injury. The objective of this study was to determine the anatomic relationship of the hypoglossal nerve (HN), internal carotid artery (ICA), bony structures, and hypoglossal canal and demonstrate the vulnerability of the neurovascular structures. Methods Eleven fresh cadavers (5 male and 6 female) were dissected bilaterally to expose neurovascular structures of the high anterior cervical region and hypoglossal canal. The anatomical relationship was evaluated between C1 bony structures (midline, lateral mass, and C1 transverse process) and the ICA and HN. The angle of the hypoglossal canal was also evaluated. Results The HN consistently traveled toward the midline at C2–3 and was safe caudal to C3–4. The HN is usually located lateral to the ICA. Relative anatomical relationship between the HN and surrounding bony structures at the level of C1 are as given below. The mean diameter of the HN was 2.4 mm (2–3.5 mm). The mean distance between the midline and the HN was 30.15 mm (24–35 mm). The mean distance between the margin of the C1 lateral mass (LM) and the HN was 4 mm (−3–11 mm). The mean distance between the C1 transverse process and the HN was 9.3 mm (3–16 mm). The transverse angle of the hypoglossal canal was between 31.6 and 55.5 degrees. The mean distance between the midline and the ICA was 26.06 mm (18–32 mm). In the cases of the medially displaced ICA, the HN is located more on the medial side relative to the LM. There was no reversed anatomical location of the HN and the ICA in the studied specimen. Conclusion On the basis of this study, spine surgeons can have enhanced knowledge of upper cervical anatomy. Although it has been rarely reported in the literature, the hypoglossal nerve and the ICA may be damaged during upper cervical spine surgery, especially in the cases with the ICA displaced medially.

Papillary Thyroid Carcinoma Presented with Huge Bone Metastases – Right Ileum and Frontal Bones

Papillary thyroid carcinoma (PTC) without metastases is most curable cancer. However, it rarely metastasizes to bone and in those cases prognosis is poor. A 55 years old female has presented with history of painless swelling on frontal region of skull for one year and limping gait to National Institute of Nuclear Medicine and Allied Sciences (NINMAS) in September 2013. She also had total thyroidectomy for multinodular goiter in early 2013. She had history of excision of swelling on frontal region in July of same year. Histopathological report of excised mass confirmed metastatic PTC. The patient again developed visible swelling on frontal region of skull suggesting recurrence. Her serum TSH was low 0.89 mIU/L without levothyroxine supplement may be due to thyroid hormones produced from metastatic masses. Serum thyroglobulin level was 464 ng/ml. X-ray of pelvis and skull showed huge soft tissue masses arising from right ileum and a lytic lesion on posterior aspect of frontal region. Whole body bone scan with 99m Technetium methylene diphosphonate (MDP) revealed a ‘doughnut’ lesion of frontal bone and a big lesion with ‘hot’ and ‘cold’ areas in right ileum and. On ultrasound scan, there was huge solid mass (about 10.0 cm× 7.0 cm) with some inhomogeneity and central cystic changes in medial aspect of right hip bone extending to pelvic cavity. Similar mass corresponded the visible swelling on skull. This mass was extended to intracranial region. Color Doppler study showed vascularity within and at margins of masses. To avoid risk of raised intracranial pressure following radioiodine therapy we sent the patient for external beam radiation therapy (EBRT) for reduction of the size of masses. Patient under went 5 cycles of EBRT (total 2000 c Gy in each lesion) but there were no reductions of sizes within one month follow up period. Small bony metastatic lesions from PTC in early stage are curable by surgical removal and repeated dose of radioiodine therapy. PTC with multiple advanced bony metastases shows poor prognosis. DOI: http://dx.doi.org/10.3329/bjnm.v17i1.22504 Bangladesh J. Nuclear Med. 17(1): 125-132, January 2014

Impact of islet size on pancreatic islet transplantation and potential interventions to improve outcome.

Better results have been recently reported in clinical pancreatic islet transplantation (ITX) due mostly to improved isolation techniques and immunosuppression; however, some limitations still exist. It is known that following transplantation, 30% to 60% of the islets are lost. In our study, we have investigated 1) the role of size as a factor affecting islet engraftment and 2) potential procedural manipulations to increase the number of smaller functional islets that can be transplanted. C57/BL10 mice were used as donors and recipients in a syngeneic islet transplant model. Isolated islets were divided by size (large, >300 μm; medium 150-300 μm; small, <150 μm). Each size was transplanted in chemically induced diabetic mice as full (600 IEQ), suboptimal (400 IEQ), and marginal mass (200 IEQ). Control animals received all size islets. Engraftment was defined as reversal of diabetes by day 7 posttransplantation. When the superiority of smaller islets was observed, strategies of overdigestion and fragmentation were adopted during islet isolation in the attempt to reduce islet size and improve engraftment. Smaller islets were significantly superior in engraftment compared to medium, large, and control (all sizes) groups. This was more evident when marginal mass data were compared. In all masses, success decreased as islet size increased. Once islets were engrafted, functionality was not affected by size. When larger islets were fragmented, a significant decrease in islet functionality was observed. On the contrary, if pancreata were slightly overdigested, although not as successful as small naive islets, an increase in engraftment was observed when compared to the control group. In conclusion, smaller islets are superior in engraftment following islet transplantation. Fragmentation has a deleterious effect on islet engraftment. Islet isolations can be performed by reducing islet size with slight overdigestion, and it can be safely adopted to improve clinical outcome.

Enhancement of islet engraftment and achievement of long-term islet allograft survival by Toll-like receptor 4 blockade.

Toll-like receptors are key players in sterile inflammation phenomena and can link the innate and adaptive immune systems by enhancing graft immunogenicity. They are also considered mediators of types 1 and 2 diabetes development. The aim of the present study was to assess the role of Toll-like receptor-4 (TLR4) in mediating the inflammatory and immune responses to pancreatic islets, thereby promoting inflammatory destruction and immune rejection of islet grafts. Experiments were conducted in murine and human in vitro systems and in vivo murine islet transplant models, using species-specific anti-TLR4 monoclonal antibodies. In vitro, mixed lymphocyte-islet reaction experiments were performed to assess T-cell activation and proliferation. In vivo, both a syngeneic (B6-to-B6) marginal mass islet transplant model to assess the impact of TLR4 blockade on islet engraftment and an allogeneic (DBA1-to-B6) model were used. In vitro TLR4 blockade decreased lipopolysaccharide-mediated β-cell apoptosis and T-cell activation and proliferation against allogeneic islets. In vivo, TLR4 blockade resulted in significantly better syngeneic marginal mass islet engraftment and in indefinite allogeneic islet graft survival. Tolerance was not observed because donor-specific skin graft rechallenge in nonrejecting animals resulted in rejection of both skin and islets, but without accelerated rejection as compared to naive animals. Taken together, our data indicate that TLR4 blockade leads to a significant improvement of syngeneic islet engraftment and of allogeneic islet graft survival. A mechanism of graft accommodation with concurrent inhibition of donor-specific immune memory is likely to be involved.

Редокс-свойства метиленового голубого как перспективного фотометрического реагента для определения галогенных окислителей

P urpose of the research was to study the interactions of redox systems containing various acid-base forms of the thiazine dye methylene blue used as a photometric reagent (reducing agent), and defined oxohalogen as oxidants. Conditions of the sensitivity and selectivity increasing for photometric redox determination toxic oxohalogen: hypochlorite, chlorite, chlorate, perchlorate, bromate, iodate and periodate-ions in water solution were founded. Much attention was paid to the purity of the reagent, which was released from the methylated thiazines. Methylene blue is easily oxidized by atmospheric oxygen and light. Therefore the conditions under which remained stable over time the ratio of its oxidized and reduced forms were created. Absorption spectrums of methylene blue in various acidity were shown, analytical wavelengths were established and value of the molar absorption coefficients of photometric reagent in different pH range and formal electrode potentials of methylene blue were calculated. Sequence of analytical procedures for separate oxohalogen determination in the combined present in solution was shown. Marginal mass ratios for oxoanions determination were determined. Detection limits were (mg/L): 3∙10 −2 (ClO − , ClO 2 − ); 5∙10 −2 (ClO 3 − ); 3∙10 −1 (ClO 4 − ) и 4∙10 −4 (BrO 3 − ); 2∙10 −4 (IO 3 − ) и 5∙10 −4 (IO 4 − ). Relative analysis error was 5-15% (according to a number of determination ions in the solution). Keywords : methylene blue, redox properties, photometric reagent, halogen oxidants (Russian) DOI: http://dx.doi.org/10.15826/analitika.2015.19.2.005 E.V. Nayanova, E.V. Elipasheva, G.M. Sergeev, V.P. Sergeeva Department of Chemistry, Lobachevsky State University, Nizhny Novgorod, Russian Federation

Endothelial Progenitor Cells Enhance Islet Engraftment, Influence β-Cell Function, and Modulate Islet Connexin 36 Expression

The success of pancreatic islet transplantation is limited by delayed engraftment and suboptimal function in the longer term. Endothelial progenitor cells (EPCs) represent a potential cellular therapy that may improve the engraftment of transplanted pancreatic islets. In addition, EPCs may directly affect the function of pancreatic β-cells. The objective of this study was to examine the ability of EPCs to enhance pancreatic islet transplantation in a murine syngeneic marginal mass transplant model and to examine the mechanisms through which this occurs. We found that cotransplanted EPCs improved the cure rate and initial glycemic control of transplanted islets. Gene expression data indicate that EPCs, or their soluble products, modulate the expression of the β-cell surface molecule connexin 36 and affect glucose-stimulated insulin release in vitro. In conclusion, EPCs are a promising candidate for improving outcomes in islet transplantation, and their mechanisms of action warrant further study.

Improved islet transplantation outcome by the co-delivery of siRNAs for iNOS and 17β-estradiol using an R3V6 peptide carrier

Silencing target genes such as inducible nitric oxide synthase (iNOS) using small interfering double-stranded RNA (siRNA) in islet cells has been attempted to enhance the survival of transplanted islets. However, the efficient and safe delivery of siRNA into intact islets is challenging. Here, we prepared R3V6 peptides containing a three-arginine stretch and a six-valine stretch, which form micelles with hydrophobic valine cores and cationic arginine surfaces in aqueous solution, to co-deliver siRNA and cytoprotective hydrophobic drugs to islet cells. The cationic surfaces bound to the negatively charged iNOS siRNA, and the hydrophobic core was loaded with 17β-estradiol (E2), which exerts anti-apoptotic effects on the islet cells. The E2-loaded R3V6 peptide micelles delivered siRNA-5′-FITC to mouse islets more efficiently than did Lipofectamine 2000, and without cytotoxicity. The micelle complexes containing siRNA-iNOS knocked down the expression of iNOS mRNA by >60% in islets and reduced cytokine-induced apoptotic cell death in vitro significantly. The delivery of siRNA-iNOS and E2 simultaneously using E2-loaded R3V6 peptide micelles improved the diabetes reversal rate of marginal mass islet transplantation into the renal subcapsular space of diabetic syngeneic mice significantly compared with the siRNA-iNOS and E2 alone treatment control groups. Our results demonstrated that the co-delivery of siRNA and a cytoprotective drug within a single non-toxic carrier, R3V6 peptide micelles, provides a novel rational strategy for combined ex vivo islet therapy to improve the outcome of islet transplantation.

Anakinra and Tocilizumab Enhance Survival and Function of Human Islets during Culture: Implications for Clinical Islet Transplantation

Pretreatment culture before islet transplantation represents a window of opportunity to ameliorate the proinflammatory profile expressed by human β-cells in duress. Anakinra (IL-1 receptor antagonist) and tocilizumab (monoclonal IL-6 receptor antibody) are two known anti-inflammatory agents successfully used in the treatment of inflammatory states like rheumatoid arthritis. Both compounds have also been shown to reduce blood glucose and glycosylated hemoglobin in diabetic patients. We therefore sought to evaluate the impact of anakinra and tocilizumab on human β-cells. The islets were precultured with or without anakinra or tocilizumab and then transplanted in a marginal mass model using human islets in immunodeficient mice. Islet viability was evaluated in an in vitro model. The pretreatment culture led to a significantly improved engraftment in treated islets compared to the vehicle. Anakinra and tocilizumab are not toxic to human islets and significantly reduce markers of inflammation and cell death. These results strongly support a pretreatment culture with anakinra and tocilizumab prior to human islet transplantation.

Cone beam breast CT with multiplanar and three dimensional visualization in differentiating breast masses compared with mammography

ObjectiveThis pilot study was to evaluate cone beam breast computed tomography (CBBCT) with multiplanar and three dimensional (3D) visualization in differentiating breast masses in comparison with two-view mammograms. MethodsSixty-five consecutive female patients (67 breasts) were scanned by CBBCT after conventional two-view mammography (Hologic, Motarget, compression factor 0.8). For CBBCT imaging, three hundred (1024×768×16b) two-dimensional (2D) projection images were acquired by rotating the x-ray tube and a flat panel detector (FPD) 360 degree around one breast. Three-dimensional CBBCT images were reconstructed from the 2D projections. Visage CS 3.0 and Amira 5.2.2 were used to visualize reconstructed CBBCT images. ResultsEighty-five breast masses in this study were evaluated and categorized under the breast imaging reporting and data system (BI-RADS) according to plain CBBCT images and two-view mammograms, respectively, prior to biopsy. BI-RADS category of each breast was compared with biopsy histopathology. The results showed that CBBCT with multiplanar and 3D visualization would be helpful to identify the margin and characteristics of breast masses. The category variance ratios for CBBCT under the BI-RADS were 23.5% for malignant tumors (MTs) and 27.3% for benign lesions in comparison with pathology, which were evidently closer to the histopathology results than those of two-view mammograms, p value <0.01. With the receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) of CBBCT was 0.911, larger than that (AUC 0.827) of two-view mammograms, p value <0.01. ConclusionCBBCT will be a distinctive noninvasive technology in differentiating and categorizing breast masses under BI-RADS. CBBCT may be considerably more effective to identify breast masses, especially some small, uncertain or multifocal masses than conventional two-view mammography.

Endothelial Progenitor Cell (EPC) Co-Transplantation Enhances the Engraftment of Pancreatic Islets and Influences Beta Cell Function In Vitro.

Islet transplantation is limited by suboptimal revascularization post-transplant. EPCs may have the potential to promote islet engraftment and improve post-transplant survival in vivo, but their mechanism of interaction with β-cells is unknown. Our aim was to assess the ability of EPCs to improve islet transplantation outcomes in a syngeneic marginal mass mouse model. C57B6 islets were isolated by Liberase® digestion and density purification. Bone marrow-derived EPCs were enriched by culture in defined media and phenotype confirmed by flow cytometry. Diabetes was induced in C57B6 mice by streptozotocin (200mg/kg) and marginal mass of islets (200) was transplanted under the kidney capsule with or without d7 EPCs (1x106 cells). Blood glucose levels (BGL) were monitored for 28d with cure defined by two consecutive BGL<11.1mM. Graft function was assessed in cured mice by intraperitoneal glucose tolerance test (IPGTT;2g/kg glucose). To assess cellular interactions, islets were cultured with EPC-conditioned medium for 3d and assayed for glucose-stimulated insulin release. Secreted insulin was measured by ELISA and corrected for total protein. EPCs expressed the endothelial marker CD31, bound lectin and took up acetylated low-density lipoprotein. Mice co-transplanted with EPCs had an improved cure rate (83% cure at d14; n=12) compared to mice receiving islets alone (20%; n=10; p=0.002). There was no significant difference in IPGTT. EPC-conditioned islets had increased basal insulin release (0.7±0.22ng/min/mg; n=7) compared to controls (0.2±0.04ng/min/mg; n=6; p=0.05). However, they had reduced ability to upregulate insulin release in high glucose conditions (SI=1.3±0.5 compared to 4.2±0.9 for controls; p<0.05). EPCs alter insulin secretion from β-cells and may improve their engraftment during pancreatic islet transplantation.