Aims/hypothesis A reliable method for in vivo quantification of pancreatic beta cell mass (BCM) could lead to further insight into the pathophysiology of diabetes. The glucagonlike peptide 1 receptor, abundantly expressed on beta cells, may be a suitable target for imaging. We investigated the potential of radiotracer imaging with the GLP-1 analogue exendin labelled with indium-111 for determination of BCM in vivo in a rodent model of beta cell loss and in patients with type 1 diabetes and healthy individuals. MethodsThe targeting of 111 In-labelled exendin was examined in a rat model of alloxan-induced beta cell loss. Rats were injected with 15 MBq 111 In-labelled exendin and single photon emission computed tomography (SPECT) acquisition was performed 1 h post injection, followed by dissection, biodistribution and ex vivo autoradiography studies of pancreatic sections. BCM was determined by morphometric analysis after staining with an anti-insulin antibody. For clinical evaluation SPECT was acquired 4, 24 and 48 h after injection of 150 MBq 111 In-labelled exendin in five patients with type 1 Maarten Brom and Wietske Woliner-van der Weg contributed equally to this study. Diabetologia (2014) 57:950-959 DOI 10.1007 diabetes and five healthy individuals. The tracer uptake was determined by quantitative analysis of the SPECT images. Results In rats, 111 In-labelled exendin specifically targets the beta cells and pancreatic uptake is highly correlated with BCM. In humans, the pancreas was visible in SPECT images and the pancreatic uptake showed high interindividual variation with a substantially lower uptake in patients with type 1 diabetes. Conclusions/interpretation These studies indicate that 111 Inlabelled exendin may be suitable for non-invasive quantification of BCM.

For more than a decade, researchers have been trying to develop non-invasive imaging techniques for the in vivo measurement of viable pancreatic beta cells. However, in spite of intense research efforts, only one tracer for positron emission tomography (PET) imaging is currently under clinical evaluation. To many diabetologists it may remain unclear why the imaging world struggles to develop an effective method for non-invasive beta cell imaging (BCI), which could be useful for both research and clinical purposes. Here, we provide a concise overview of the obstacles and challenges encountered on the way to such BCI, in both native and transplanted islets. We discuss the major difficulties posed by the anatomical and cell biological features of pancreatic islets, as well as the chemical and physical limits of the main imaging modalities, with special focus on PET, SPECT and MRI. We conclude by indicating new avenues for future research in the field, based on several remarkable recent results.

Aims/hypothesis While the mechanisms of specification and the reciprocal relationships of the four types of endocrine cell (alpha, beta, delta and pancreatic polypeptide cells) within the human endocrine pancreas are well described in adults and during fetal development, ghrelin-immunoreactive cells (epsilon cells) remain poorly understood. Methods We studied epsilon cells in 24 human fetal pancreases between 11 and 39 weeks of development and in 32 pancreases from adult organ donors. Results We observed single epsilon cells scattered in primitive exocrine tissue from gestational week 13 in developing pancreas. Later in the developmental process, epsilon cells started to aggregate into clusters. From gestational week 21, epsilon cells were observed located around developing islets, forming an almost continuous layer at the peripheral rim of the islets. They remain localised on the mantle of the islets, although at different amounts, in the adult pancreas. Coproduction of ghrelin with insulin, glucagon or somatostatin was not detected during fetal development. Co-production with pancreatic polypeptide was evident sporadically. Epsilon cells co-produced NK2 homeobox 2 and ISL LIM homeobox 1, but not NK6 homeobox 1 and paired box 6. A quantitative analysis was performed in the adult pancreas: there was an average of 1.17+1.17 epsilon cells per islet, the relative epsilon cell volume was 0.14+0.16% and the epsilon cell mass was 0.13+0.15 g. Neither sex nor age affected the epsilon cell mass, although there was a significant inverse correlation with BMI. Conclusions/interpretation During fetal development epsilon cells show an ontogenetic and morphogenetic pattern that is distinct from that of alpha and beta cells.

Although in a clinical setting islet transplantation is normally performed by percutaneous intrahepatic infusion, the kidney capsule has been the site of choice in nearly all the studies using mice. In the present study, we extensively characterized the mouse model of intraportally transplanted islets with the purpose to propose it as a model to study islet transplantation. C57BL/6 (n = 78) and BALB/C (n = 53) recipients were transplanted with 400 autologous islets alternatively through the portal vein (PV-Tx) or under the kidney capsule (KC-Tx). Glucose concentration during the first hour after syngeneic islet infusion was associated with subsequent long-term function confirming that early events have long-term effects on graft function. In both strains tested the probability to achieve islet function was significantly lower for PV-Tx than KC-Tx. Also in allogeneic models (C57BL/6 to BALB/C, n = 104; BALB/C to C57BL/6, n = 77) the probability to achieve primary function was significantly lower for PV-Tx than KC-Tx and the site of transplantation significantly affected the graft survival. Histological evaluation of livers showed the presence of features (embolism, thrombosis, focal areas of liver necrosis) that are absent in the kidney subcapsular site. Finally, significant differences in the outcome of PV-Tx were observed between the Th type 1 inflammatory-prone C57BL/6 mouse and the type 2 inflammatory-prone BALB/C mouse. Intraportal islet graft model has some features that are more similar to human clinical islet transplantation and should be used as a model to study not only engraftment but also mechanisms of immune suppression and immune tolerance. INTRODUCTIONing engraftment in the liver (5) has been suggested to be a prime factor necessitating the very large number of islets needed to achieve normoglycemia (2). InvestigaRodent models have been widely used to study the causal mechanisms of failure of islet transplantation and tion of the mechanisms of islet cell loss during intahepatic islet transplantation and of ways to prevent their loss to test protocols aimed at preventing islet graft failure. In most rodent models, islets are transplanted under the would seem important (24,27). Yet, few studies in murine models address this be means of intrahepatic transkidney capsule, whereas islet transplantation in humans is performed by percutaneous intrahepatic infusion plantation. A systematic study of the intrahepatic islet transplant in the mouse model is also lacking. through the portal vein (25). Intrahepatic islet infusion in humans is associated with an immediate blood-mediHere we describe allogenic and syngeneic intrahepatic islet transplantation models in two mouse strains, ated inflammatory reaction, thrombosis, and hepatic tissue ischemia (1,2,(4)(5)(6)13,18,22,23,28). Kidney subcapdescribe outcome in detail, and compare it with that of renal subcapsular islet transplantation. The findings sular transplantation is not intravascular and is devoid of these complications. Thus, although transplantation ...

The changes in beta-cell mass (BCM) during the course of diabetes are not yet well characterized. A non-invasive method to measure the BCM in vivo would allow us to study the BCM during the onset and progression of the diseases caused by beta-cell dysfunction. PET and SPECT imaging are attractive approaches to determine the BCM because of their high sensitivity and the possibility to quantitatively analyze the images. Several targets and their corresponding radiotracers have been examined for their ability to determine the BCM including radiolabeled antibodies, antibody fragments, peptides and small molecules. Although some of these tracers show promising results, there is still no reliable method to determine the beta-cell mass in vivo. In this review, the targets and the corresponding radiotracers evaluated so far for the determination of the BCM in vivo in humans will be discussed.

Introduction: Cervical cancer affects half a million women worldwide annually. Given the association between high-risk human papillomavirus (hrHPV) infection and carcinogenesis, hrHPV DNA testing became an essential diagnostic tool. However, hrHPV alone does not cause the disease, and, most importantly, many cervical lesions regress to normal in a year because of the host immune system. Hence, the low specificity of hrHPV DNA tests and their inability to predict the outcome of infections have triggered a further search for biomarkers. Areas covered: We evaluated the latest viral and cellular biomarkers validated for clinical use as primary screening or triage for cervical cancer and assessed their promise for prevention as well as potential use in the future. The literature search focused on effective biomarkers for different stages of the disease, aiming to determine their significance in predicting the outcome of hrHPV infections. Expert opinion: Biomarkers such as p16/Ki-67, hrHPV genotyping, hrHPV transcriptional status, and methylation patterns have demonstrated promising results. Their eventual implementation in the screening programs may support the prompt diagnosis of hrHPV infection and its progression to cancer. These biomarkers will help in making clinical management decisions on time, thus, saving the lives of hrHPV-infected women, particularly in developing countries.

Germ cells contain non-membrane bound cytoplasmic organelles that help maintain germline integrity. In C. elegans they are called P granules; without them, the germline undergoes partial masculinization and aberrant differentiation. One key P-granule component is the Argonaute CSR-1, a small-RNA binding protein that antagonizes accumulation of sperm-specific transcripts in developing oocytes and fine-tunes expression of proteins critical to early embryogenesis. Loss of CSR-1 complex components results in a very specific, enlarged P-granule phenotype. In a forward screen to identify mutants with abnormal P granules, ten alleles were recovered with a csr-1 P-granule phenotype, eight of which contain mutations in known components of the CSR-1 complex (csr-1, ego-1, ekl-1, and drh-3). The remaining two alleles are in a novel gene now called elli-1 (enlarged germline granules). ELLI-1 is first expressed in primordial germ cells during mid-embryogenesis, and continues to be expressed in the adult germline. While ELLI-1 forms cytoplasmic aggregates, they occasionally dock, but do not co-localize with P granules. Instead, the majority of ELLI-1 aggregates accumulate in the shared germline cytoplasm. In elli-1 mutants, several genes that promote RNAi and P-granule accumulation are upregulated, and embryonic lethality, sterility, and RNAi resistance in a hypomorphic drh-3 allele is enhanced, suggesting that ELLI-1 functions with CSR-1 to modulate RNAi activity, P-granule accumulation, and post-transcriptional expression in the germline.

Objectives: To determine the live birth rate for patients who chose to undergo treatment with Restorative Reproductive Medicine (RRM) after previous IVF (includes ICSI). To look at birth outcomes with RRM after IVF, particularly rates of twin and higher order pregnancies, premature birth, low birth weight, and potential cost savings achieved with RRM.Setting: Two outpatient clinics in Ireland providing advanced RRM treatment of infertility.Materials and methods: All patients presenting between January 2004 and January 2010, with a history of infertility and previous IVF treatment were included if they proceeded beyond the initial consultation and began treatment. Main outcome is live birth per couple calculated using life table analysis.Results: 403 patients met the study criteria, among which 74 had a subsequent live birth. These women had significant negative predictive characteristics for healthy live birth including: advanced reproductive age (average 37.2 years), an average of 5.8 years of infertility with 2.1 (range 1–9) previous IVF attempts, with only 5% having previously had a live birth from IVF. Despite these undesirable prognostic indicators, the overall RRM live birth rate was 32.1% (crude 18.4%). Women aged 35–38 had a live birth rate of 37.5% (crude 23.6%) and older women over 40 had a live birth rate of 27.4% (crude 16.0%). The average birth weight was 3374g (7lb 7oz) with 92% being born at 37+ weeks and no very low birth weight babies. There was only one twin pregnancy in the study population; the potential health care savings for avoidable multiple pregnancies in these patients was estimated at £205 672 (USD$284 915).Conclusions: Patients who have already tried IVF can achieve comparable live birth outcomes with RRM compared to another cycle of IVF. RRM has a low risk of twin or multiple births, and very good neonatal outcomes with a potential cost savings to the health care system.