Genetic variants for head size share genes and pathways with cancer

The size of the human head is highly heritable, but genetic drivers of its variation within the general population remain unmapped. We perform a genome-wide association study on head size (N = 80,890) and identify 67 genetic loci, of which 50 are novel. Neuroimaging studies show that 17 variants affect specific brain areas, but most have widespread effects. Gene set enrichment is observed for various cancers and the p53, Wnt, and ErbB signaling pathways. Genes harboring lead variants are enriched for macrocephaly syndrome genes (37-fold) and high-fidelity cancer genes (9-fold), which is not seen for human height variants. Head size variants are also near genes preferentially expressed in intermediate progenitor cells, neural cells linked to evolutionary brain expansion. Our results indicate that genes regulating early brain and cranial growth incline to neoplasia later in life, irrespective of height. This warrants investigation of clinical implications of the link between head size and cancer.

Early detection of white matter hyperintensities using SHIVA-WMH detector

White matter hyperintensities (WMHs) are well-established markers of cerebral small vessel disease, and are associated with an increased risk of stroke, dementia, and mortality. Although their prevalence increases with age, small and punctate WMHs have been reported with surprisingly high frequency even in young, neurologically asymptomatic adults. However, most automated methods to segment WMH published to date are not optimized for detecting small and sparse WMH. Here we present the SHIVA-WMH tool, a deep-learning (DL)-based automatic WMH segmentation tool that has been trained with manual segmentations of WMH in a wide range of WMH severity. We show that it is able to detect WMH with high efficiency in subjects with only small punctate WMH as well as in subjects with large WMHs (i.e., with confluency) in evaluation datasets from three distinct databases: magnetic resonance imaging-Share consisting of young university students, MICCAI 2017 WMH challenge dataset consisting of older patients from memory clinics, and UK Biobank with community-dwelling middle-aged and older adults. Across these three cohorts with a wide-ranging WMH load, our tool achieved voxel-level and individual lesion cluster-level Dice scores of 0.66 and 0.71, respectively, which were higher than for three reference tools tested: the lesion prediction algorithm implemented in the lesion segmentation toolbox (LPA: Schmidt), PGS tool, a DL-based algorithm and the current winner of the MICCAI 2017 WMH challenge (Park et al.), and HyperMapper tool (Mojiri Forooshani et al.), another DL-based method with high reported performance in subjects with mild WMH burden. Our tool is publicly and openly available to the research community to facilitate investigations of WMH across a wide range of severity in other cohorts, and to contribute to our understanding of the emergence and progression of WMH.

Association of retinal nerve layers thickness and brain imaging in healthy young subjects from the i-Share-Bordeaux study

Given the anatomical and functional similarities between the retina and the brain, the retina could be a "window" for viewing brain structures. We investigated the association between retinal nerve fiber layers (peripapillary retinal nerve fiber layer, ppRNFL; macular ganglion cell-inner plexiform layer, GC-IPL; and macular ganglion cell complex, GCC), and brain magnetic resonance imaging (MRI) parameters in young health adults. We included 857 students (mean age: 23.3 years, 71.3% women) from the i-Share study. We used multivariate linear models to study the cross-sectional association of each retinal nerve layer thickness assessed by spectral-domain optical coherence tomography (SD-OCT) with structural (volumes and cortical thickness), and microstructural brain markers, assessed on MRI globally and regionally. Microstructural MRI parameters included diffusion tensor imaging (DTI) and Neurite Orientation Dispersion and Density Imaging (NODDI). On global brain analysis, thicker ppRNFL, GC-IPL and GCC were all significantly associated with patterns of diffusion metrics consistent with higher WM microstructural integrity. In regional analyses, after multiple testing corrections, our results suggested significant associations of some retinal nerve layers with brain regional gray matter occipital volumes and with diffusion MRI parameters in a region involved in the visual pathway and in regions containing associative tracts. No associations were found with global volumes or with global or regional cortical thicknesses. Results of this study suggest that some retinal nerve layers may reflect brain structures. Further studies are needed to confirm these results in young subjects.

Genomics of perivascular space burden unravels early mechanisms of cerebral small vessel disease

Perivascular space (PVS) burden is an emerging, poorly understood, magnetic resonance imaging marker of cerebral small vessel disease, a leading cause of stroke and dementia. Genome-wide association studies in up to 40,095 participants (18 population-based cohorts, 66.3 ± 8.6 yr, 96.9% European ancestry) revealed 24 genome-wide significant PVS risk loci, mainly in the white matter. These were associated with white matter PVS already in young adults (N = 1,748; 22.1 ± 2.3 yr) and were enriched in early-onset leukodystrophy genes and genes expressed in fetal brain endothelial cells, suggesting early-life mechanisms. In total, 53% of white matter PVS risk loci showed nominally significant associations (27% after multiple-testing correction) in a Japanese population-based cohort (N = 2,862; 68.3 ± 5.3 yr). Mendelian randomization supported causal associations of high blood pressure with basal ganglia and hippocampal PVS, and of basal ganglia PVS and hippocampal PVS with stroke, accounting for blood pressure. Our findings provide insight into the biology of PVS and cerebral small vessel disease, pointing to pathways involving extracellular matrix, membrane transport and developmental processes, and the potential for genetically informed prioritization of drug targets.

Genomic studies across the lifespan point to early mechanisms determining subcortical volumes

BACKGROUND

Subcortical brain structures play a key role in pathological processes of age-related neurodegenerative disorders. Mounting evidence also suggests that early-life factors may have an impact on the development of common late-life neurological diseases, including genetic factors that can influence both brain maturation and neurodegeneration.

METHODS

Using large population-based brain imaging datasets across the lifespan (N<40,628) we aimed to: (i) estimate the heritability of subcortical volumes in young (18-35), middle (35-65), and older age (65+), and their genetic correlation across age groups; (ii) identify whether genetic loci associated with subcortical volumes in older persons also show associations in early adulthood, and explore underlying genes using transcriptome-wide association studies; (iii) explore their association with neurological phenotypes.

RESULTS

Heritability of subcortical volumes consistently decreased with increasing age. Genetic risk scores for smaller caudate nucleus, putamen and hippocampus volume in older adults were associated with smaller volumes in young adults. Individually, ten loci associated with subcortical volumes in older adults also showed associations in young adults. Within these loci, transcriptome-wide association studies showed that expression of several genes in brain tissues (especially MYLK2 and TUFM) was associated with subcortical volumes in both age-groups. One risk variant for smaller caudate nucleus volume (TUFM locus) was associated with lower cognitive performance. Genetically-predicted Alzheimer's disease was associated with smaller subcortical volumes in middle and older age.

CONCLUSIONS

Our findings provide novel insights into the genetic determinants of subcortical volumes across the lifespan. More studies are needed to decipher the underlying biology and clinical impact.

Is GLP-1 insufficiency a coronary risk factor? A multicenter observational study, BOREAS-CAD2

Background and aim

Glucagon-like peptide-1 (GLP-1) regulates insulin secretion and also affords pleiotropic effects including protective effects on blood vessels. Multiple factors regulate GLP-1 secretion after meals, but a group of apparently healthy subjects showed blunted responses of GLP-1 secretion in our previous study. In this study, we examined the possibility that the reduced capacity of GLP-1 secretion is associated with increased extent of coronary artery stenosis in non-diabetic patients.

Methods and results

Non-diabetic patients who were admitted for coronary angiography without a history of coronary interventions were enrolled. Coronary artery stenosis was quantified by Gensini score (GS), and GS ≥10 was used as an outcome variable based on results of earlier studies indicating its predictive value for cardiovascular events. The patients (mean age, 66.5±8.8 years; 71% males, n=173) underwent oral 75 g-glucose tolerant tests for determination of glucose, insulin and active GLP-1 levels. The area under the curve of plasma active GLP-1 (AUC-GLP-1) was determined as an index of GLP-1 secretion capacity. AUC-GLP-1 was not correlated with fasting glucose, AUC-glucose, serum lipids, indices of insulin sensitivity or estimated glomerular filtration rate. In multivariate logistic regression analysis for GS ≥10, AUC-GLP-1 &lt; median, age and hypertension were selected as explanatory variables, though fasting GLP-1 level was not selected.

Conclusion

The findings indicate significant association of reduced GLP-1 secretion capacity with increased extent of coronary artery stenosis in non-diabetic patients. A causal relationship between change in GLP-1 secretion capacity and coronary stenosis remains to be examined by a longitudinal study

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was supported in part by a research grant from Investigator-Initiated Studies Program of Merck Sharp & Dohme Corp./MSD K.K.

Novel characterization of the relationship between verbal list-learning outcomes and hippocampal subfields in healthy adults

The relationship between hippocampal subfield volumetry and verbal list‐learning test outcomes have mostly been studied in clinical and elderly populations, and remain controversial. For the first time, we characterized a relationship between verbal list‐learning test outcomes and hippocampal subfield volumetry on two large separate datasets of 447 and 1,442 healthy young and middle‐aged adults, and explored the processes that could explain this relationship. We observed a replicable positive linear correlation between verbal list‐learning test free recall scores and CA1 volume, specific to verbal list learning as demonstrated by the hippocampal subfield volumetry independence from verbal intelligence. Learning meaningless items was also positively correlated with CA1 volume, pointing to the role of the test design rather than word meaning. Accordingly, we found that association‐based mnemonics mediated the relationship between verbal list‐learning test outcomes and CA1 volume. This mediation suggests that integrating items into associative representations during verbal list‐learning tests explains CA1 volume variations: this new explanation is consistent with the associative functions of the human CA1.

Age-Related Variations in Regional White Matter Volumetry and Microstructure During the Post-adolescence Period: A Cross-Sectional Study of a Cohort of 1,713 University Students

Human brain white matter undergoes a protracted maturation that continues well into adulthood. Recent advances in diffusion-weighted imaging (DWI) methods allow detailed characterizations of the microstructural architecture of white matter, and they are increasingly utilized to study white matter changes during development and aging. However, relatively little is known about the late maturational changes in the microstructural architecture of white matter during post-adolescence. Here we report on regional changes in white matter volume and microstructure in young adults undergoing university-level education. As part of the MRi-Share multi-modal brain MRI database, multi-shell, high angular resolution DWI data were acquired in a unique sample of 1,713 university students aged 18-26. We assessed the age and sex dependence of diffusion metrics derived from diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) in the white matter regions as defined in the John Hopkins University (JHU) white matter labels atlas. We demonstrate that while regional white matter volume is relatively stable over the age range of our sample, the white matter microstructural properties show clear age-related variations. Globally, it is characterized by a robust increase in neurite density index (NDI), and to a lesser extent, orientation dispersion index (ODI). These changes are accompanied by a decrease in diffusivity. In contrast, there is minimal age-related variation in fractional anisotropy. There are regional variations in these microstructural changes: some tracts, most notably cingulum bundles, show a strong age-related increase in NDI coupled with decreases in radial and mean diffusivity, while others, mainly cortico-spinal projection tracts, primarily show an ODI increase and axial diffusivity decrease. These age-related variations are not different between males and females, but males show higher NDI and ODI and lower diffusivity than females across many tracts. These findings emphasize the complexity of changes in white matter structure occurring in this critical period of late maturation in early adulthood.

Causal Prefrontal Contributions to Stop-Signal Task Performance in Humans

The frontal lobes have long been implicated in inhibitory control, but a full understanding of the underlying mechanisms remains elusive. The stop-signal task has been widely used to probe instructed response inhibition in cognitive neuroscience. The processes involved have been modeled and related to putative brain substrates. However, there has been surprisingly little human lesion research using this task, with the few existing studies implicating different prefrontal regions. Here, we tested the effects of focal prefrontal damage on stop-signal task performance in a large sample of people with chronic focal damage affecting the frontal lobes (n = 42) and demographically matched healthy individuals (n = 60). Patients with damage to the left lateral, right lateral, dorsomedial, or ventromedial frontal lobe had slower stop-signal RT compared to healthy controls. There were systematic differences in the patterns of impairment across frontal subgroups: Those with damage to the left or right lateral and dorsomedial frontal lobes, but not those with ventromedial frontal damage, were slower than controls to "go" as well as to stop. These findings suggest that multiple prefrontal regions make necessary but distinct contributions to stop-signal task performance. As a consequence, stop-signal RT slowing is not strongly localizing within the frontal lobes.

The MRi-Share database: brain imaging in a cross-sectional cohort of 1870 university students

We report on MRi-Share, a multi-modal brain MRI database acquired in a unique sample of 1870 young healthy adults, aged 18-35 years, while undergoing university-level education. MRi-Share contains structural (T1 and FLAIR), diffusion (multispectral), susceptibility-weighted (SWI), and resting-state functional imaging modalities. Here, we described the contents of these different neuroimaging datasets and the processing pipelines used to derive brain phenotypes, as well as how quality control was assessed. In addition, we present preliminary results on associations of some of these brain image-derived phenotypes at the whole brain level with both age and sex, in the subsample of 1722 individuals aged less than 26 years. We demonstrate that the post-adolescence period is characterized by changes in both structural and microstructural brain phenotypes. Grey matter cortical thickness, surface area and volume were found to decrease with age, while white matter volume shows increase. Diffusivity, either radial or axial, was found to robustly decrease with age whereas fractional anisotropy only slightly increased. As for the neurite orientation dispersion and densities, both were found to increase with age. The isotropic volume fraction also showed a slight increase with age. These preliminary findings emphasize the complexity of changes in brain structure and function occurring in this critical period at the interface of late maturation and early ageing.

3D Segmentation of Perivascular Spaces on T1-Weighted 3 Tesla MR Images With a Convolutional Autoencoder and a U-Shaped Neural Network

We implemented a deep learning (DL) algorithm for the 3-dimensional segmentation of perivascular spaces (PVSs) in deep white matter (DWM) and basal ganglia (BG). This algorithm is based on an autoencoder and a U-shaped network (U-net), and was trained and tested using T1-weighted magnetic resonance imaging (MRI) data from a large database of 1,832 healthy young adults. An important feature of this approach is the ability to learn from relatively sparse data, which gives the present algorithm a major advantage over other DL algorithms. Here, we trained the algorithm with 40 T1-weighted MRI datasets in which all "visible" PVSs were manually annotated by an experienced operator. After learning, performance was assessed using another set of 10 MRI scans from the same database in which PVSs were also traced by the same operator and were checked by consensus with another experienced operator. The Sorensen-Dice coefficients for PVS voxel detection in DWM (resp. BG) were 0.51 (resp. 0.66), and 0.64 (resp. 0.71) for PVS cluster detection (volume threshold of 0.5 within a range of 0 to 1). Dice values above 0.90 could be reached for detecting PVSs larger than 10 mm3 and 0.95 for PVSs larger than 15 mm3. We then applied the trained algorithm to the rest of the database (1,782 individuals). The individual PVS load provided by the algorithm showed a high agreement with a semi-quantitative visual rating done by an independent expert rater, both for DWM and for BG. Finally, we applied the trained algorithm to an age-matched sample from another MRI database acquired using a different scanner. We obtained a very similar distribution of PVS load, demonstrating the interoperability of this algorithm.

Prevalence, Severity, and Clinical Management of Brain Incidental Findings in Healthy Young Adults: MRi-Share Cross-Sectional Study

Background and Objectives: Young adults represent an increasingly large proportion of healthy volunteers in brain imaging research, but descriptions of incidental findings (IFs) in this age group are scarce. We aimed to assess the prevalence and severity of IFs on brain MRIs of healthy young research participants aged 18-35 years, and to describe the protocol implemented to handle them. Methods: The study population comprised 1,867 participants aged 22.1 ± 2.3 years (72% women) from MRi-Share, the cross-sectional brain MRI substudy of the i-Share student cohort. IFs were flagged during the MRI quality control. We estimated the proportion of participants with IFs [any, requiring medical referral, potentially serious (PSIFs) as defined in the UK biobank]: overall, by type and severity of the final diagnosis, as well as the number of IFs. Results: 78/1,867 participants had at least one IF [4.2%, 95% Confidence Interval (CI) 3.4-5.2%]. IFs requiring medical referral (n = 38) were observed in 36/1,867 participants (1.9%, 1.4-2.7%), and represented 47.5% of the 80 IFs initially flagged. Referred IFs were retrospectively classified as PSIFs in 25/1,867 participants (1.3%, 0.9-2.0%), accounting for 68.4% of anomalies referred (26/38). The most common final diagnosis was cysts or ventricular abnormalities in all participants (9/1,867; 0.5%, 0.2-0.9%) and in those with referred IFs (9/36; 25.0%, 13.6-41.3%), while it was multiple sclerosis or radiologically isolated syndrome in participants with PSIFs (5/19; 26.3%, 11.5-49.1%) who represented 0.1% (0.0-0.4%) and 0.2% (0.03-0.5%) of all participants, respectively. Final diagnoses were considered serious in 11/1,867 participants (0.6%, 0.3-1.1%). Among participants with referred IFs, 13.9% (5/36) required active intervention, while 50.0% (18/36) were put on clinical surveillance. Conclusions: In a large brain imaging study of young healthy adults participating in research we observed a non-negligible frequency of IFs. The etiological pattern differed from what has been described in older adults.

Cerebral small vessel disease genomics and its implications across the lifespan

White matter hyperintensities (WMH) are the most common brain-imaging feature of cerebral small vessel disease (SVD), hypertension being the main known risk factor. Here, we identify 27 genome-wide loci for WMH-volume in a cohort of 50,970 older individuals, accounting for modification/confounding by hypertension. Aggregated WMH risk variants were associated with altered white matter integrity (p = 2.5×10-7) in brain images from 1,738 young healthy adults, providing insight into the lifetime impact of SVD genetic risk. Mendelian randomization suggested causal association of increasing WMH-volume with stroke, Alzheimer-type dementia, and of increasing blood pressure (BP) with larger WMH-volume, notably also in persons without clinical hypertension. Transcriptome-wide colocalization analyses showed association of WMH-volume with expression of 39 genes, of which four encode known drug targets. Finally, we provide insight into BP-independent biological pathways underlying SVD and suggest potential for genetic stratification of high-risk individuals and for genetically-informed prioritization of drug targets for prevention trials.

Long-term follow-up of the randomized trial of mesorectal excision with or without lateral lymph node dissection in rectal cancer (JCOG0212)

BACKGROUND

Japan Clinical Oncology Group (JCOG) 0212 (ClinicalTrials.gov NCT00190541) was a non-inferiority phase III trial of patients with clinical stage II-III rectal cancer without lateral pelvic lymph node enlargement. The trial compared mesorectal excision (ME) with ME and lateral lymph node dissection (LLND), with a primary endpoint of recurrence-free survival (RFS). The planned primary analysis at 5 years failed to confirm the non-inferiority of ME alone compared with ME and LLND. The present study aimed to compare ME alone and ME with LLND using long-term follow-up data from JCOG0212.

METHODS

Patients with clinical stage II-III rectal cancer below the peritoneal reflection and no lateral pelvic lymph node enlargement were included in this study. After surgeons confirmed R0 resection by ME, patients were randomized to receive ME alone or ME with LLND. The primary endpoint was RFS.

RESULTS

A total of 701 patients from 33 institutions were assigned to ME with LLND (351) or ME alone (350) between June 2003 and August 2010. The 7-year RFS rate was 71.1 per cent for ME with LLND and 70·7 per cent for ME alone (hazard ratio (HR) 1·09, 95 per cent c.i. 0·84 to 1·42; non-inferiority P = 0·064). Subgroup analysis showed improved RFS among patients with clinical stage III disease who underwent ME with LLND compared with ME alone (HR 1·49, 1·02 to 2·17).

CONCLUSION

Long-term follow-up data did not support the non-inferiority of ME alone compared with ME and LLND. ME with LLND is recommended for patients with clinical stage III disease, whereas LLND could be omitted in those with clinical stage II tumours.

Age-Related Changes of Peak Width Skeletonized Mean Diffusivity (PSMD) Across the Adult Lifespan: A Multi-Cohort Study

Parameters of water diffusion in white matter derived from diffusion-weighted imaging (DWI), such as fractional anisotropy (FA), mean, axial, and radial diffusivity (MD, AD, and RD), and more recently, peak width of skeletonized mean diffusivity (PSMD), have been proposed as potential markers of normal and pathological brain ageing. However, their relative evolution over the entire adult lifespan in healthy individuals remains partly unknown during early and late adulthood, and particularly for the PSMD index. Here, we gathered and analyzed cross-sectional diffusion tensor imaging (DTI) data from 10 population-based cohort studies in order to establish the time course of white matter water diffusion phenotypes from post-adolescence to late adulthood. DTI data were obtained from a total of 20,005 individuals aged 18.1 to 92.6 years and analyzed with the same pipeline for computing skeletonized DTI metrics from DTI maps. For each individual, MD, AD, RD, and FA mean values were computed over their FA volume skeleton, PSMD being calculated as the 90% peak width of the MD values distribution across the FA skeleton. Mean values of each DTI metric were found to strongly vary across cohorts, most likely due to major differences in DWI acquisition protocols as well as pre-processing and DTI model fitting. However, age effects on each DTI metric were found to be highly consistent across cohorts. RD, MD, and AD variations with age exhibited the same U-shape pattern, first slowly decreasing during post-adolescence until the age of 30, 40, and 50 years, respectively, then progressively increasing until late life. FA showed a reverse profile, initially increasing then continuously decreasing, slowly until the 70s, then sharply declining thereafter. By contrast, PSMD constantly increased, first slowly until the 60s, then more sharply. These results demonstrate that, in the general population, age affects PSMD in a manner different from that of other DTI metrics. The constant increase in PSMD throughout the entire adult life, including during post-adolescence, indicates that PSMD could be an early marker of the ageing process.

Effect of sodium-glucose co-transporter-2 inhibitors on impaired ventricular repolarization in people with Type 2 diabetes

AIMS

To test the hypothesis that treatment with a sodium-glucose co-transporter-2 inhibitor would reverse ventricular repolarization heterogeneity, a predictor of cardiovascular mortality, in people with Type 2 diabetes.

METHODS

We retrospectively analysed changes in indices of ventricular repolarization before and after treatment with a sodium-glucose co-transporter-2 inhibitor in 46 people with Type 2 diabetes.

RESULTS

Sodium-glucose co-transporter-2 inhibitor treatment reduced HbA_1c concentration [62±13 mmol/mol (7.7±1.2%) vs 59±16 mmol/mol (7.5±1.4%)], body weight (77.8±13.9 vs 74.7±12.5 kg) and systolic blood pressure (133±18 vs 126±12 mmHg) in the study participants. Heart rate and QTc interval were not changed by sodium-glucose co-transporter-2 inhibitor treatment, but QTc dispersion was significantly reduced (median, 48.8 vs 44.2 ms). Sodium-glucose co-transporter-2 inhibitor treatment reversed QTc dispersion more in participants who had larger QTc dispersion before the treatment. Changes in systolic blood pressure (Spearman's ρ= 0.319; P=0.031), but not in HbA_1c concentration, were correlated with changes in QTc dispersion after sodium-glucose co-transporter-2 inhibitor treatment.

CONCLUSIONS

The findings suggest that sodium-glucose co-transporter-2 inhibitor treatment reverses ventricular repolarization heterogeneity in people with Type 2 diabetes, independently of its effect on glycaemic control. The favourable effect on ventricular repolarization heterogeneity could be the mechanism by which empaglifozin reduced cardiovascular events in a recent study.

Autoimmune pancreatitis as the initial presentation of systemic lupus erythematosus

Pancreatitis is a relatively rare complication in systemic lupus erythematosus (SLE). Here we present a case of SLE associated with autoimmune pancreatitis. A 37-year old woman was admitted to our hospital because of fever, skin rash, proteinuria and abdominal pain. A diagnosis of SLE was made based on her clinical, laboratory and renal histological findings showing diffuse proliferative lupus nephritis. Elevated serum amylase, typical radiographic findings and selective increase in serum IgG4 all suggested that the patient also had autoimmune pancreatitis. Systemic administration of glucocorticoid successfully induced remission of pancreatitis and nephritis along with the reduction of IgG4. Autoimmune pancreatitis is a newly recognized type of pancreatitis, in which IgG4 immune response is thought to participate pathophysiologically. Although the disease has been observed to develop in patients having various connective tissue diseases, our report is the first to describe IgG4 related autoimmune pancreatitis in a patient with SLE.

Dexamethasone inhibits invasiveness of a human pancreatic cancer cell line

Recent studies have shown that dexamethasone inhibits gelatinases. We investigated the effect of dexamethasone on the invasiveness of a human pancreatic cancer cell line. Tumor cells were treated with dexamethasone at various concentrations for 24 h. Cells were examined in an invasion assay. The expression and activity of MMP-9 in culture media were quantitated by Western blotting and gelatin zymogram. The invasiveness of cancer cells and expression of MMP-9 were decreased by dexamethasone in a dose-dependent manner. Dexamethasone may be a useful therapeutic agent in the treatment of pancreatic cancer.

Chronic administration of DSP-7238, a novel, potent, specific and substrate-selective DPP IV inhibitor, improves glycaemic control and beta-cell damage in diabetic mice

AIMS

The purpose of this study is to assess the in vitro enzyme inhibition profile of DSP-7238, a novel non-cyanopyrrolidine dipeptidyl peptidase (DPP) IV inhibitor and to evaluate the acute and chronic effects of this compound on glucose metabolism in two different mouse models of type 2 diabetes.

METHODS

The in vitro enzyme inhibition profile of DSP-7238 was assessed using plasma and recombinant enzymes including DPP IV, DPP II, DPP8, DPP9 and fibroblast activation protein alpha (FAPalpha) with fluorogenic substrates. The inhibition type was evaluated based on the Lineweaver-Burk plot. Substrate selectivity of DSP-7238 and comparator DPP IV inhibitors (vildagliptin, sitagliptin, saxagliptin and linagliptin) was evaluated by mass spectrometry based on the changes in molecular weight of peptide substrates caused by release of N-terminal dipeptides. In the in vivo experiments, high-fat diet-induced obese (DIO) mice were subjected to oral glucose tolerance test (OGTT) following a single oral administration of DSP-7238. To assess the chronic effects of DSP-7238 on glycaemic control and pancreatic beta-cell damage, DSP-7238 was administered for 11 weeks to mice made diabetic by a combination of high-fat diet (HFD) and a low-dose of streptozotocin (STZ). After the dosing period, HbA1c was measured and pancreatic damage was evaluated by biological and histological analyses.

RESULTS

DSP-7238 and sitagliptin both competitively inhibited recombinant human DPP IV (rhDPP IV) with K(i) values of 0.60 and 2.1 nM respectively. Neither vildagliptin nor saxagliptin exhibited competitive inhibition of rhDPP IV. DSP-7238 did not inhibit DPP IV-related enzymes including DPP8, DPP9, DPP II and FAPalpha, whereas vildagliptin and saxagliptin showed inhibition of DPP8 and DPP9. Inhibition of glucagon-like peptide-1 (GLP-1) degradation by DSP-7238 was apparently more potent than its inhibition of chemokine (C-X-C motif) ligand 10 (IP-10) or chemokine (C-X-C motif) ligand 12 (SDF-1alpha) degradation. In contrast, vildagliptin and saxagliptin showed similar degree of inhibition of degradation for all the substrates tested. Compared to treatment with the vehicle, single oral administration of DSP-7238 dose-dependently decreased plasma DPP IV activity and improved glucose tolerance in DIO mice. In addition, DSP-7238 significantly decreased HbA1c and ameliorated pancreatic damage following 11 weeks of chronic treatment in HFD/STZ mice.

CONCLUSIONS

We have shown in this study that DSP-7238 is a potent DPP IV inhibitor that has high specificity for DPP IV and substrate selectivity against GLP-1. We have also found that chronic treatment with DSP-7238 improves glycaemic control and ameliorates beta-cell damage in a mouse model with impaired insulin sensitivity and secretion. These findings indicate that DSP-7238 may be a new therapeutic agent for the treatment of type 2 diabetes.

Lesion evidence that two distinct regions within prefrontal cortex are critical for n-back performance in humans

Although prefrontal cortex is clearly important in executive function, the specific processes carried out by particular regions within human prefrontal cortex remain a matter of debate. A rapidly growing corpus of functional imaging work now implicates various areas within prefrontal cortex in a wide range of "executive" tasks. Loss-of-function studies can help constrain the interpretation of such evidence by testing to what extent particular brain areas are necessary for a given cognitive process. Here we apply a component process analysis to understand prefrontal contributions to the n-back task, a widely used test of working memory, in a cohort of patients with focal prefrontal damage. We investigated letter 2-back task performance in 27 patients with focal damage to various regions within prefrontal cortex, compared to 29 demographically matched control subjects. Both "behavior-defined" approaches, using qualitative lesion analyses and voxel-based lesion-symptom mapping methods, and more conventional "lesion-defined" groupwise comparisons were undertaken to determine the relationships between specific sites of damage within prefrontal cortex and particular aspects of n-back task performance. We confirmed a critical role for left lateral prefrontal cortex in letter 2-back performance. We also identified a critical role for medial prefrontal cortex in this task: Damage to dorsal anterior cingulate cortex and adjacent dorsal fronto-medial cortex led to a pattern of impairment marked by high false alarm rates, distinct from the impairment associated with lateral prefrontal damage. These findings provide converging support for regionally specific models of human prefrontal function.

Comparison of the antidiabetic effects of brain-derived neurotrophic factor and thiazolidinediones in obese diabetic mice

AIMS

Brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism in obese diabetic db/db mice. The antidiabetic effect of BDNF is dependent on plasma insulin levels, and BDNF enhances insulin action by modulating insulin signalling in peripheral tissues. The aim of the study was to compare the antidiabetic effects of BDNF with those of thiazolidinediones (TZDs), which are insulin-sensitizing agents, through evaluation of the effects of BDNF and TZDs on glucose metabolism, energy expenditure, pancreatic function and hepatic steatosis in db/db mice.

METHODS

The effects of BDNF, pioglitazone and rosiglitazone on blood glucose concentration, body weight and pancreatic insulin and glucagon contents and the effects of BDNF and troglitazone treatment for 3 weeks on blood glucose concentration, body and liver weights and histological liver images were examined in db/db mice. Furthermore, since BDNF reduces food intake in obese hyperphagic diabetic mice, the effects of BDNF treatment for 3 weeks on blood glucose concentration, body weight, fat pad and liver weights and rectal temparature in db/db mice were compared with those of troglitazone under pair-fed conditions.

RESULTS

BDNF, pioglitazone and rosiglitazone all ameliorated hyperglycaemia in db/db mice, but BDNF increased the pancreatic insulin content more effectively than pioglitazone and rosiglitazone. The pancreatic glucagon content decreased with BDNF, but increased with pioglitazone and rosiglitazone compared with vehicle, and body weight and liver weight increased with troglitazone, but decreased with BDNF compared with vehicle. Histological analysis of the liver showed that BDNF treatment reduced the massive vacuolization observed with vehicle, whereas troglitazone worsened the vacuolization. Body weight, fat pad and liver weights in BDNF-treated mice were significantly lower than those in pair-fed troglitazone-treated db/db mice, and rectal temperature in BDNF-treated mice was significantly higher than that in pair-fed troglitazone-treated mice, suggesting that BDNF enhances energy expenditure.

CONCLUSIONS

These data suggest that compared with TZDs, BDNF potently ameliorates pancreatic dysfunction, fatty liver and energy expenditure, thereby exerting favourable antidiabetic effects in type 2 diabetic mice.

Association of free fatty acids (FFA) and tumor necrosis factor-alpha (TNF-alpha) and insulin-resistant metabolic disorder

The roles of free fatty acids (FFA), tumor necrosis factor-alpha (TNF-alpha), and adiponectin in the development of the insulin-resistant metabolic disorder in several subjects have been studied. A total of 70 Japanese male subjects were selected according to the following three sets of criteria: subjects in group A had, (1) a fasting plasma glucose (FPG)>or=110 to <140 mg/dl, (2) a triglyceride (TG) level>or=150 mg/dl, (3) a systolic blood pressure (SBP)>or=140 and/or diastolic blood pressure (DBP)>or=90 mmHg, and (4) a body mass index (BMI)>or=25 kg/m2 (age=53.4+/-8.5 years, BMI=27.0+/-1.3 kg/m2, n=16). Subjects in group B had, (1) FPG<110 mg/dl, (2) TG<150 mg/dl, (3) SBP<140 and DBP<90 mmHg, and (4) BMI>or=25 kg/m2 (age=47.2+/-10.3 years, BMI=26.6+/-1.31 kg/m2, n=38). Subjects in group C had, (1) FPG<110 mg/dl, (2) TG<150 mg/dl, (3) SBP<140 and DBP<90 mmHg, and (4) 20>or=BMI<22 kg/m2 (age=50.4+/-9.3 years, BMI=20.9+/-0.6 kg/m2, n=16). The homeostasis model assessment of insulin resistance in group A (2.7+/-1.4) was significantly higher (p<0.0001) than in groups B (1.6+/-0.7) and C (0.9+/-0.5). FFA in group A (1.17+/-0.57 mEq/l) was significantly higher than in groups B (0.62+/-0.23 mEq/l) and C (0.48+/-0.16 mEq/l) (p<0.0001). Serum TNF-alpha in group A (1.36+/-0.62 pg/ml) was significantly higher than in groups B (0.95+/-0.35 pg/ml; p=0.003) and C (0.76+/-0.09 pg/ml; p=0.0013). No significant differences in the serum level of adiponectin were observed between groups A and B or between groups B and C. The results suggest that FFA and possibly TNF-alpha levels are closely related to the development of insulin resistance in subjects with metabolic disorders.

Brain-derived neurotrophic factor enhances glucose utilization in peripheral tissues of diabetic mice

AIMS

Repetitive subcutaneous or intracerebroventricular administration of brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism and enhances energy expenditure in obese diabetic C57BL/KsJ-db/db mice. To explore the mechanism of action through which BDNF regulates glucose metabolism, we examined the effects of BDNF on glucose utilization and norepinephrine (NE) content in peripheral tissues of diabetic mice.

METHODS

[(14)C]2-deoxyglucose ([(14)C]2-DG) uptake into peripheral tissues was analysed after intravenous injection of [(14)C]2-DG in db/db and normal C57BL/6 mice, and [(14)C]2-DG uptake and NE content in peripheral tissues were analysed after subcutaneous administration of BDNF (20 mg/kg) to male db/db and normal mice for 8 days.

RESULTS

[(14)C]2-DG uptake in the diaphragm, heart, gastrocnemius, soleus and interscapular brown adipose tissue (BAT) of db/db mice was significantly lower than in normal mice. Repetitive administration of BDNF to db/db mice for 8 days enhanced [(14)C]2-DG uptake in the diaphragm, heart, soleus, BAT and liver. The NE content in heart, skeletal muscle, interscapular BAT and liver of db/db mice given BDNF was high compared with db/db mice given vehicle, whereas no significant change in NE content in peripheral tissues was observed in normal mice given BDNF and those given vehicle. BDNF did not affect [(14)C]2-DG uptake or NE content in the white adipose tissue of db/db mice.

CONCLUSIONS

These data indicate that BDNF ameliorates glucose metabolism by enhancement of glucose utilization in muscle and BAT, with this effect caused by modulation of the central and peripheral nervous systems.

Combination chemotherapy with docetaxel and nedaplatin for recurrent esophageal cancer in an outpatient setting

The purpose of this study was to address the feasibility of combination chemotherapy of docetaxel and nedaplatin for recurrent esophageal cancer patients in an outpatient setting. Patients received docetaxel (30 mg/m(2) intravenously) on day 1 and nedaplatin (40 mg/m(2) intravenously) on day 1 every 2 weeks. In total, 28 patients with recurrent esophageal cancer after the initial treatment (esophagectomy, chemotherapy and/or chemoradiotherapy) were enrolled. Each patient received six cycles of treatment and was evaluated with a computed tomography scan. The percentage of patients who completed this therapy was 60.7%. Complete response and partial response were achieved by 3.6% and 35.7% of patients, respectively. The most frequent toxicities were leukopenia and anemia; non-hematological toxicities were generally mild. There was no treatment-related death. The median survival time and 1-year survival rate were 8.5 months and 15.9%, respectively. This outpatient combination chemotherapy was useful as second-line chemotherapy for recurrent esophageal cancer.

Puncture of solid pancreatic tumors guided by endoscopic ultrasonography: a pilot study series comparing Trucut and 19-gauge and 22-gauge aspiration needles

BACKGROUND AND STUDY AIMS

The aim of this prospective study was to compare endoscopic ultrasonography-guided Trucut needle biopsy (EUS-TNB) with EUS-guided fine-needle aspiration biopsy (EUS-FNAB) using 19- and 22-gauge needles for biopsy from different sites in patients with solid pancreatic cancers.

PATIENTS AND METHODS

Sixteen consecutive patients with masses in the uncinate process (n = 3), the head (n = 5), or the body and tail (n = 8) of the pancreas underwent both EUS-TNB and EUS-FNAB. The specimens obtained were evaluated by histopathological analysis alone

RESULTS

Tissue specimens were obtained by Trucut needle, and by 19-gauge and 22-gauge aspiration needles in 69 %, 69 %, and 100 % of patients respectively. Sensitivity for malignancy was 69 % for all needles. Tissue sampling by Trucut and by 19-gauge aspiration needle from masses in the uncinate process was impossible. The sensitivity of the Trucut and 19-gauge aspiration needles was 100 % in the 11 patients with successful procedures. If Trucut or 19-gauge aspiration needles had been used for body and tail masses, and the 22-gauge aspiration needle for masses in the uncinate process and head, the sensitivity for malignancy would have been 81 %.

CONCLUSIONS

EUS-TNB allows reliable tissue sampling for the diagnosis of pancreatic masses, but its use is limited to lesions in the body and tail of the pancreas. EUS-FNAB using a 22-gauge needle may be useful for accurate diagnosis in some patients with masses in the uncinate process or the head of the pancreas.

Anti-obesity and anti-diabetic effects of brain-derived neurotrophic factor in rodent models of leptin resistance

OBJECTIVE

Obesity in rodents and humans is mostly associated with elevated plasma leptin concentrations, suggesting a new pathological concept of 'leptin resistance'. We have demonstrated that brain-derived neurotrophic factor (BDNF) can improve obesity and diabetes of C57BL/KsJ db/db (db/db) mice. In this study, we investigated whether or not BDNF is effective in two different models of leptin resistance, an acquired model and a genetic model.

DESIGN

C57BL/6J mice rendered obese by consumption of a high-fat diet (diet-induced obesity (DIO) mice) were used as an acquired model and lethal yellow agouti mice (KKA(y) mice) as a genetic model of leptin resistance. Food intake and glucose metabolism were studied after acute or repetitive administration of BDNF.

RESULTS

Intraperitoneal administration of BDNF (10 mg/kg, twice/day) significantly reduced cumulative food intake of DIO and KKA(y) mice, whereas they were unresponsive to leptin administration. Repetitive subcutaneous administration of BDNF (10 mg/kg daily for 6 days) reduced food intake and improved impaired glucose tolerance in DIO mice. Pair feeding of vehicle-treated DIO mice with the same amount of chow consumed by the BDNF-treated group did not improve the impaired glucose homeostasis, indicating that the antidiabetic effect is not due to decreased food intake. We also observed that BDNF is effective in improving obesity and diabetes of KKA(y) mice.

CONCLUSION

This study demonstrated antiobesity and antidiabetic effects of BDNF in two different models of leptin resistance, thereby suggesting the therapeutic potential of BDNF in the treatment of leptin-resistant obesity and diabetes.

Activation of peroxisome proliferator-activated receptor gamma inhibits the growth of human pancreatic cancer

OBJECTIVE

In the present study, we examined the expression of peroxisome proliferator-activated receptor gamma (PPARgamma) in human pancreatic cancer and the possible effects of its ligand engagement on cell growth.

METHODS

Seven human pancreatic cancer cell lines and 7 surgically resected human pancreatic cancer tissues were used as samples. The expression of PPARgamma was analyzed with reverse transcription-polymerase chain reaction and immunoblotting. The interaction between PPARgamma and PPAR-responsive element (PPRE) was examined by gel shift assay. Growth inhibition by thiazolidinediones was confirmed with anchorage-dependent and anchorage-independent growth assays.

RESULTS

PPARgamma was detected in all cell lines tested and in 5 out of 7 cancer tissues (71%), but was not found in adjacent normal pancreatic tissues. Gel shift analysis revealed that the proteins in nuclear extracts of the pancreatic cancer cell line PANC-1 specifically bind to the PPRE. Cell growth was significantly inhibited by treatment with troglitazone and rosiglitazone in a dose- and time-dependent manner (p < 0.01). In contrast, a nonfunctional metabolic analog of troglitazone did not affect cell growth.

CONCLUSION

These observations suggest that PPARgamma plays an important role in human pancreatic cancer growth and that ligand-induced activation of PPARgamma would be a useful strategy for treatment of human pancreatic cancer.

Brain-derived neurotrophic factor ameliorates lipid metabolism in diabetic mice

AIM

It has been reported previously that brain-derived neurotrophic factor (BDNF) regulates blood glucose metabolism in rodent obese diabetic models such as C57BL/KsJ-leprdb/leprdb (db/db) mice. BDNF further regulates energy expenditure, possibly through the central and autonomous nervous systems. In this study, we evaluated the effect of BDNF on both lipid and glucose metabolisms to clarify its action mechanism.

METHODS

To control the energy intake, we used a pellet pair-feeding apparatus to synchronize food intake precisely between BDNF-treated and vehicle-treated db/db mice. BDNF (50 mg/kg/week) was subcutaneously injected to male db/db mice twice weekly for 3 weeks, and blood glucose, serum biochemical lipid parameters and tissue weights were measured. Liver triglyceride contents were measured and liver sections were histologically analysed.

RESULTS

Twice weekly BDNF treatment for 3 weeks significantly lowered blood glucose compared with pellet pair-fed, vehicle-treated db/db mice (294 +/- 109 vs. 529 +/- 91 mg/dL). Serum non-esterified free fatty acid (726 +/- 72 vs. 999 +/- 220 microEq/l), total cholesterol (125 +/- 8 vs. 151 +/- 23 mg/dL) and phospholipid levels (215 +/- 13 vs. 257 +/- 36 mg/dL) of the BDNF-treated db/db mice decreased significantly. Liver weights (1.51 +/- 0.11 vs. 2.05 +/- 0.11 g), liver triglyceride contents (17.5 +/- 1.4 vs. 26.1 +/- 2.1 mg/g) and fatty liver in histological appearance were reduced with BDNF treatment. There were no significant differences in body weights and white adipose tissue weights between the two groups.

CONCLUSIONS

Taken together with the accelerating effect of BDNF on energy metabolism, these findings indicate that BDNF improves glucose and lipid metabolism in obese diabetic animals without enlarging liver or adipose tissues.

Comparative study of self-expandable metallic stent and bypass surgery for inoperable esophageal cancer

We evaluated the effect of two different therapies for 23 patients with inoperable esophageal cancer, of whom 13 patients underwent placement of a metallic stent and 10 received bypass surgery. We newly defined the improved level of food intake and the effective rate based on the grade of the patient's status in order to evaluate objectively. Although the effect of stent placement was significantly better than that of bypass surgery, there were no significant differences in the improved level of food intake and the effective rate between the two groups. Four out of 10 patients in the bypass group had suture insufficiency, resulting in no oral intake and a fatal outcome. In addition, the ratio of survival period of ability to ingest orally and in-hospital mortality was significantly favorable in the stent group compared with the bypass group. In conclusion, stent placement should be the first choice for inoperable malignant stenosis or esophageal fistula.

Is frozen section effective for diagnosis of unsuspected gallbladder cancer during laparoscopic cholecystectomy?

BACKGROUND

Although frozen section is recommended to prevent tumor dissemination following laparoscopic cholecystectomy (LC) for unsuspected gallbladder cancer, there are no reports concretely demonstrating its effectiveness and outcome.

METHODS

Frozen section during LC was performed in 990 patients with gallstones. The sensitivity, specificity of frozen section, and false-negative cases were evaluated in comparison with postoperative entire cross sections.

RESULTS

In frozen section, 983 cases were diagnosed as benign and 7 cases as malignant. Of the benign cases, cancer was discovered in 4 patients postoperatively in which frozen section was diagnosed as regenerative epithelial severe atypia. Sensitivity was 64% and specificity was 100%. Concerning the results of frozen section by p-TNM classification, cancer was diagnosed in 40% of Tis lesions, whereas it was found in 83% of T2 or T3 lesions.

CONCLUSION

Frozen section is effective in cases with T2 or greater lesions for which conversion to radical surgery should be required.