Imperial College London

DrVictoriaSalem

Faculty of EngineeringDepartment of Bioengineering

Diabetes UK Harry Keen Research Fellow
 
 
 
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v.salem

 
 
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Commonwealth BuildingHammersmith Campus

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Summary

 

Publications

Publication Type
Year
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56 results found

de Jesus DS, Mak TCS, Wang Y-F, von Ohlen Y, Bai Y, Kane E, Chabosseau P, Chahrour CM, Distaso W, Salem V, Tomas A, Stoffel M, Rutter GA, Latreille Met al., 2021, Dysregulation of the Pdx1/Ovol2/Zeb2 axis in dedifferentiated β-cells triggers the induction of genes associated with epithelial-mesenchymal transition in diabetes, Molecular Metabolism, Vol: 53, ISSN: 2212-8778

OBJECTIVE: β-cell dedifferentiation has been revealed as a pathological mechanism underlying pancreatic dysfunction in diabetes. We previously showed that increased miR-7 levels trigger β-cell dedifferentiation and diabetes. We used β-cell-specific miR-7 overexpressing mice (Tg7) to test the hypothesis that loss of β-cell identity triggered by miR-7 overexpression alters islet gene expression and islet microenvironment in diabetes. METHODS: We performed bulk and single-cell RNA sequencing (RNA-seq) in islets obtained from β-cell-specific miR-7 overexpressing mice (Tg7). We carried out loss- and gain-of-function experiments in MIN6 and EndoC-bH1 cell lines. We analysed previously published mouse and human T2D data sets. RESULTS: Bulk RNA-seq revealed that β-cell dedifferentiation is associated with the induction of genes associated with epithelial-to-mesenchymal transition (EMT) in prediabetic (2-week-old) and diabetic (12-week-old) Tg7 mice. Single-cell RNA-seq (scRNA-seq) indicated that this EMT signature is enriched specifically in β-cells. These molecular changes are associated with a weakening of β-cell: β-cell contacts, increased extracellular matrix (ECM) deposition, and TGFβ-dependent islet fibrosis. We found that the mesenchymal reprogramming of β-cells is explained in part by the downregulation of Pdx1 and its inability to regulate a myriad of epithelial-specific genes expressed in β-cells. Notable among genes transactivated by Pdx1 is Ovol2, which encodes a transcriptional repressor of the EMT transcription factor Zeb2. Following compromised β-cell identity, the reduction in Pdx1 gene expression causes a decrease in Ovol2 protein, triggering mesenchymal reprogramming of β-cells through the induction of Zeb2. We provided evidence that EMT signalling associated with the upregulation of Zeb2 expression is a molecular feature of islets in T2D subjects. CONCLUSIONS: Our study indicates that m

Journal article

Akalestou E, Suba K, Lopez-Noriega L, Georgiadou E, Chabosseau P, Gallie A, Wretlind A, Legido-Quigley C, Leclerc I, Salem V, Rutter GAet al., 2021, Intravital imaging of islet Ca2+ dynamics reveals enhanced beta cell connectivity after bariatric surgery in mice (vol 12, 5165, 2021), NATURE COMMUNICATIONS, Vol: 12

Journal article

Salem V, McDonagh J, Avis E, Eng PC, Smith S, Murphy KGet al., 2021, Scientific medical conferences can be easily modified to improve female inclusion: a prospective study., The Lancet Diabetes and Endocrinology, Vol: 9, Pages: 556-559, ISSN: 2213-8595

Journal article

Akalestou E, Suba K, Lopez-Noriega L, Georgiadou E, Chabosseau P, Gallie A, Wretlind A, Quigley C, Leclerc I, Salem V, Rutter GAet al., 2021, Intravital imaging of islet Ca2+ dynamics reveals enhanced beta cell connectivity after bariatric surgery in mice, NATURE COMMUNICATIONS, Vol: 12

Journal article

Salem V, Demetriou L, Behary P, Alexiadou K, Scholtz S, Tharakan G, Miras A, Purkayastha S, Ahmed A, Bloom S, Wall M, Dhillo W, Tan Tet al., 2021, Weight loss by low calorie diet versus gastric bypass surgery in people with diabetes results in divergent brain activation patterns: an functional MRI study, Diabetes Care, Vol: 44, Pages: 1842-1851, ISSN: 0149-5992

OBJECTIVE: Weight loss achieved with very-low-calorie diets (VLCDs) can produce remission of type 2 diabetes (T2D), but weight regain very often occurs with reintroduction of higher calorie intakes. In contrast, bariatric surgery produces clinically significant and durable weight loss, with diabetes remission that translates into reductions in mortality. We hypothesized that in patients living with obesity and prediabetes/T2D, longitudinal changes in brain activity in response to food cues as measured using functional MRI would explain this difference.RESEARCH DESIGN AND METHODS: Sixteen participants underwent gastric bypass surgery, and 19 matched participants undertook a VLCD (meal replacement) for 4 weeks. Brain responses to food cues and resting-state functional connectivity were assessed with functional MRI pre- and postintervention and compared across groups.RESULTS: We show that Roux-en-Y gastric bypass surgery (RYGB) results in three divergent brain responses compared with VLCD-induced weight loss: 1) VLCD resulted in increased brain reward center food cue responsiveness, whereas in RYGB, this was reduced; 2) VLCD resulted in higher neural activation of cognitive control regions in response to food cues associated with exercising increased cognitive restraint over eating, whereas RYGB did not; and 3) a homeostatic appetitive system (centered on the hypothalamus) is better engaged following RYGB-induced weight loss than VLCD.CONCLUSIONS: Taken together, these findings point to divergent brain responses to different methods of weight loss in patients with diabetes, which may explain weight regain after a short-term VLCD in contrast to enduring weight loss after RYGB.

Journal article

Misra S, Khozoee B, Huang-Jiawei P, Mitsaki K, Reddy M, Salem V, Tan T, Tharakan G, Gable D, Bravis V, Valabhji Jet al., 2021, Comparison of diabetic ketoacidosis in adults, during the SARS-CoV-2 outbreak and over the same time period for the 3 preceding years, Diabetes Care, Vol: 44, Pages: e29-e31, ISSN: 0149-5992

Journal article

Izzi-Engbeaya C, Distaso W, Amin A, Kenkre J, Abdel-Malek M, Hope D, Oliver N, Misra S, Tan T, Hill N, Salem Vet al., 2021, Adverse outcomes in COVID-19 and diabetes – a retrospective cohort study from three London Teaching hospitals, BMJ Open Diabetes Research and Care, Vol: 9, Pages: 1-10, ISSN: 2052-4897

INTRODUCTION: Patients with diabetes mellitus admitted to hospital with COVID-19 have poorer outcomes. However, the drivers for this are not fully elucidated. We performed detailed characterisation of COVID-19 patients to determine clinical and biochemical factors that may be the drivers of poorer outcomes. RESEARCH DESIGN AND METHODS: Retrospective cohort study of 889 consecutive inpatients diagnosed with COVID-19 between 9th March 2020 and 22nd April 2020 in a large London NHS Trust. Unbiased multivariate logistic regression analysis was performed to determine variables that were independently and significantly associated with increased risk of death and/or ICU admission within 30 days of COVID-19 diagnosis. RESULTS: 62% of patients in our cohort were of non-White ethnic backgrounds and the diabetes prevalence was 38%. 323 (36%) patients met the primary outcome of death/admission to the intensive care unit (ICU) within 30 days of COVID-19 diagnosis. Male gender, lower platelet count, advancing age and higher Clinical Frailty Scale (CFS) score (but not diabetes) independently predicted poor outcomes on multivariate analysis. Antiplatelet medication was associated with a lower risk of death/ICU admission. Factors that were significantly and independently associated with poorer outcomes in patients with diabetes were co-existing ischaemic heart disease, increasing age and lower platelet count. CONCLUSIONS: In this large study of a diverse patient population, comorbidity (i.e. diabetes with ischaemic heart disease; increasing CFS score in older patients) were major determinants of poor outcomes with COVID-19. Antiplatelet medication should be evaluated in randomised clinical trials amongst high-risk patient groups.

Journal article

Jones B, Fang Z, Chen S, Manchanda Y, Bitsi S, Pickford P, David A, Shchepinova MM, Corrêa Jr IR, Hodson DJ, Broichhagen J, Tate EW, Reimann F, Salem V, Rutter GA, Tan T, Bloom SR, Tomas Aet al., 2020, Ligand-specific factors influencing GLP-1 receptor post-endocytic trafficking and degradation in pancreatic beta cells, International Journal of Molecular Sciences, Vol: 212, Pages: 1-24, ISSN: 1422-0067

The glucagon-like peptide-1 receptor (GLP-1R) is an important regulator of blood glucose homeostasis. Ligand-specific differences in membrane trafficking of the GLP-1R influence its signalling properties and therapeutic potential in type 2 diabetes. Here, we have evaluated how different factors combine to control the post-endocytic trafficking of GLP-1R to recycling versus degradative pathways. Experiments were performed in primary islet cells, INS-1 832/3 clonal beta cells and HEK293 cells, using biorthogonal labelling of GLP-1R to determine its localisation and degradation after treatment with GLP-1, exendin-4 and several further GLP-1R agonist peptides. We also characterised the effect of a rare GLP1R coding variant, T149M, and the role of endosomal peptidase endothelin-converting enzyme-1 (ECE-1), in GLP1R trafficking. Our data reveal how treatment with GLP-1 versus exendin-4 is associated with preferential GLP-1R targeting towards a recycling pathway. GLP-1, but not exendin-4, is a substrate for ECE-1, and the resultant propensity to intra-endosomal degradation, in conjunction with differences in binding affinity, contributes to alterations in GLP-1R trafficking behaviours and degradation. The T149M GLP-1R variant shows reduced signalling and internalisation responses, which is likely to be due to disruption of the cytoplasmic region that couples to intracellular effectors. These observations provide insights into how ligand- and genotype-specific factors can influence GLP-1R trafficking.

Journal article

Hameed S, Salem V, Alessimii H, Scholtz S, Dar O, Miras AD, Meeran K, Bloom SR, Ahmed AR, Purkayastha S, Chahal H, Tan Tet al., 2020, Imperial Satiety Protocol: A new non-surgical weight-loss programme, delivered in a health care setting, produces improved clinical outcomes for people with obesity, Diabetes, Obesity and Metabolism: a journal of pharmacology and therapeutics, Vol: 23, Pages: 270-275, ISSN: 1462-8902

‘Imperial Satiety Protocol’ (I-SatPro) is a new multifaceted approach to weight loss for people with obesity (PwO), encompassing dietary advice, time-restricted eating, physical activity and coaching to support behaviour change. Participants (n = 84) attended fortnightly I-SatPro group sessions for 30 weeks, with 70% of participants completing. On completion at 30 weeks, the mean weight loss was 15.2 ± 1.1 kg (13.2 ± 0.8% from baseline, P < .0001), which was maintained to 52 weeks (16.6 ± 1.5 kg, 14.1 ± 1.2%, P < .0001). Weight loss was not associated with reduced energy expenditure. In participants with type 2 diabetes and pre-diabetes (n = 16), glycated haemoglobin fell from 50 to 43 mmol/mol (P < .01). Systolic blood pressure fell by 12 mmHg (P < .0001). Triglycerides fell by 0.37 mmol/L (P < .01) and high-density lipoprotein rose by 0.08 mmol/L (P < .01). Short Form-36 (SF-36) functioning and wellbeing scores increased in all domains post I-SatPro intervention. For selected PwO, I-SatPro delivers clinically meaningful weight loss, and the potential for long-term health and wellbeing improvements.

Journal article

Muniangi-Muhitu H, Akalestou E, Salem V, Misra S, Oliver NS, Rutter GAet al., 2020, Covid-19 and diabetes: a complex bidirectional relationship, Frontiers in Endocrinology, Vol: 11, ISSN: 1664-2392

Covid-19 is a recently-emerged infectious disease caused by the novel severe acute respiratory syndrome coronavirus SARS-CoV2. SARS-CoV2 differs from previous coronavirus infections (SARS and MERS) due to its high infectivity (reproduction value, R0, typically 2-4) and pre- or asymptomatic transmission, properties that have contributed to the current global Covid-19 pandemic. Identified risk factors for disease severity and death from SARS-Cov2 infection include older age, male sex, diabetes, obesity and hypertension. The reasons for these associations are still largely obscure. Evidence is also emerging that SARS-CoV2 infection exacerbates the underlying pathophysiology of hyperglycemia in people with diabetes. Here, we discuss potential mechanisms through which diabetes may affect the risk of more severe outcomes in Covid-19 and, additionally, how diabetic emergencies and longer term pathology may be aggravated by infection with the virus. We consider roles for the immune system, the observed phenomenon of microangiopathy in severe Covid-19 infection and the potential for direct viral toxicity on metabolically-relevant tissues including pancreatic beta cells and targets of insulin action.

Journal article

Carrat GR, Haythorne E, Tomas A, Haataja L, Müller A, Arvan P, Piunti A, Cheng K, Huang M, Pullen TJ, Georgiadou E, Stylianides T, Amirruddin NS, Salem V, Distaso W, Cakebread A, Heesom KJ, Lewis PA, Hodson DJ, Briant LJ, Fung ACH, Sessions RB, Alpy F, Kong APS, Benke PI, Torta F, Keong Teo AK, Leclerc I, Solimena M, Wigley DB, Rutter GAet al., 2020, The type 2 diabetes gene product STARD10 is a phosphoinositide-binding protein that controls insulin secretory granule biogenesis, Molecular Metabolism, Vol: 40, ISSN: 2212-8778

OBJECTIVE: Risk alleles for type 2 diabetes at the STARD10 locus are associated with lowered STARD10 expression in the β-cell, impaired glucose-induced insulin secretion, and decreased circulating proinsulin:insulin ratios. Although likely to serve as a mediator of intracellular lipid transfer, the identity of the transported lipids and thus the pathways through which STARD10 regulates β-cell function are not understood. The aim of this study was to identify the lipids transported and affected by STARD10 in the β-cell and the role of the protein in controlling proinsulin processing and insulin granule biogenesis and maturation. METHODS: We used isolated islets from mice deleted selectively in the β-cell for Stard10 (βStard10KO) and performed electron microscopy, pulse-chase, RNA sequencing, and lipidomic analyses. Proteomic analysis of STARD10 binding partners was executed in the INS1 (832/13) cell line. X-ray crystallography followed by molecular docking and lipid overlay assay was performed on purified STARD10 protein. RESULTS: βStard10KO islets had a sharply altered dense core granule appearance, with a dramatic increase in the number of "rod-like" dense cores. Correspondingly, basal secretion of proinsulin was increased versus wild-type islets. The solution of the crystal structure of STARD10 to 2.3 Å resolution revealed a binding pocket capable of accommodating polyphosphoinositides, and STARD10 was shown to bind to inositides phosphorylated at the 3' position. Lipidomic analysis of âStard10KO islets demonstrated changes in phosphatidylinositol levels, and the inositol lipid kinase PIP4K2C was identified as a STARD10 binding partner. Also consistent with roles for STARD10 in phosphoinositide signalling, the phosphoinositide-binding proteins Pirt and Synaptotagmin 1 were amongst the differentially expressed genes in βStard10KO islets. CONCLUSION: Our data indicate that STARD10 binds to, and may transp

Journal article

Akalestou E, Suba K, Lopez-Noriega L, Georgiadou E, Chabosseau P, Leclerc I, Salem V, Rutter GAet al., 2020, Metabolic surgery recovers Ca(2+)dynamics across pancreatic islets in obese mice, 56th Annual Meeting of the European-Association-for-the-Study-of-Diabetes (EASD), Publisher: SPRINGER, Pages: S114-S114, ISSN: 0012-186X

Conference paper

Rutter GA, Ninov N, Salem V, Hodson DJet al., 2020, Comment on Satin et al. "Take Me To Your Leader": An Electrophysiological Appraisal of the Role of Hub Cells in Pancreatic Islets. Diabetes 2020;69:830-836, DIABETES, Vol: 69, Pages: E10-E11, ISSN: 0012-1797

Journal article

Alonso AM, Cork SC, Ma Y, Arnold M, Herzog H, Bloom SR, Distaso W, Murphy KG, Salem Vet al., 2020, The Vagus Nerve Mediates the Physiological but not Pharmacological Effects of PYY3-36 on Food Intake

<jats:title>Abstract</jats:title><jats:p>Peptide YY (PYY<jats:sub>3-36</jats:sub>) is a post-prandially released gut hormone with potent appetite-reducing activity mediated by the neuropeptide Y (NPY) Y2 receptor (Y2R). However, the neuronal pathways by which PYY<jats:sub>3-36</jats:sub> acts to supress appetite are unclear. Determining how the PYY<jats:sub>3-36</jats:sub> system physiologically regulates food intake may help exploit its therapeutic potential. Here we demonstrate that germline and post-natal targeted knockdown of the Y2R in the afferent vagus nerve inhibits the anorectic effects of physiologically-released PYY<jats:sub>3-36</jats:sub>, but not peripherally-administered higher doses. Post-natal knockdown of the Y2R results in a transient body weight phenotype that is compensated for in the germline model. Loss of vagal Y2R signalling also alters meal patterning and accelerates gastric emptying. These results may facilitate the design of PYY-based anti-obesity agents.</jats:p><jats:sec><jats:title>Abstract Figure</jats:title><jats:fig id="ufig1" position="float" fig-type="figure" orientation="portrait"><jats:graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="241851v1_ufig1" position="float" orientation="portrait" /></jats:fig></jats:sec>

Journal article

Hopkins M, Andrews R, Salem V, Taylor R, le Roux CW, Robertson E, Burns Eet al., 2020, Improving understanding of type 2 diabetes remission: research recommendations from Diabetes UK's 2019 remission workshop, DIABETIC MEDICINE, Vol: 37, Pages: 1944-1950, ISSN: 0742-3071

Journal article

Suba K, Patel YS, Alonso AM, Scott R, Minnion JS, Leclerc I, Owen B, Distaso W, Tan TM, Murphy K, Bloom S, Rutter GA, Salem Vet al., 2020, Chronic Administration of a Long-Acting Glucagon Analogue Results in Enhanced Insulin Secretory Activity in a Directly-Observed Murine Model, 80th Scientific Sessions of the American-Diabetes-Association (ADA), Publisher: AMER DIABETES ASSOC, ISSN: 0012-1797

Conference paper

Salem V, Ali U, Suba K, Bitsi S, Lopes T, Alonso AM, Patel YS, Leclerc I, Owen B, Rutter GA, Rothery SM, Tomas Aet al., 2020, Upregulation of Pancreatic Islet EGF Receptor Improves Beta-Cell Identity and In Vivo Vascularisation in a Directly Observed Transplant Model, 80th Scientific Sessions of the American-Diabetes-Association (ADA), Publisher: AMER DIABETES ASSOC, ISSN: 0012-1797

Conference paper

Akalestou E, Suba K, Noriega LL, Chabosseau PL, Leclerc I, Salem V, Rutter GAet al., 2020, Bariatric Surgery Improves Ca2+Dynamics across Pancreatic Islets In Vivo, 80th Scientific Sessions of the American-Diabetes-Association (ADA), Publisher: AMER DIABETES ASSOC, ISSN: 0012-1797

Conference paper

Akalestou E, Suba K, Lopez-Noriega L, Georgiadou E, Chabosseau P, Leclerc I, Salem V, Rutter GAet al., 2020, Intravital imaging of islet Ca2+ dynamics reveals enhanced β cell connectivity after bariatric surgery in mice

<jats:title>Abstract</jats:title><jats:p>Bariatric surgery improves both insulin sensitivity and secretion in type 2 diabetes. However, these changes are difficult to monitor directly and independently. In particular, the degree and the time course over which surgery impacts β cell function, versus mass, have been difficult to establish. In this study, we investigated the effect of bariatric surgery on β cell function <jats:italic>in vivo</jats:italic> by imaging Ca<jats:sup>2+</jats:sup> dynamics prospectively and at the single cell level in islets engrafted into the anterior eye chamber. Islets expressing GCaMP6f selectively in the β cell were transplanted into obese male hyperglycaemic mice that were then subjected to either vertical sleeve gastrectomy (VSG) or sham surgery. Imaged <jats:italic>in vivo</jats:italic> in the eye, VSG improved coordinated Ca<jats:sup>2+</jats:sup> activity, with 90% of islets observed exhibiting enhanced Ca<jats:sup>2+</jats:sup> wave activity ten weeks post-surgery, while islet wave activity in sham animals fell to zero discernible coordinated islet Ca<jats:sup>2+</jats:sup> activity at the same time point. Correspondingly, VSG mice displayed significantly improved glucose tolerance and insulin secretion. Circulating fasting levels of GLP-1 were also increased after surgery, potentially contributing to improved β cell performance. We thus demonstrate that bariatric surgery leads to time-dependent increases in individual β cell function and intra-islet connectivity, together driving increased insulin secretion and diabetes remission, in a weight-loss independent fashion.</jats:p><jats:sec><jats:title>Significance Statement</jats:title><jats:p>Used widely to treat obesity, bariatric surgery also relieves the symptoms of type 2 diabetes. The mechanisms involved in diabetes remission are still

Journal article

Carrat GR, Haythorne E, Tomas A, Haataja L, Müller A, Arvan P, Piunti A, Cheng K, Huang M, Pullen TJ, Georgiadou E, Stylianides T, Amirruddin NS, Salem V, Distaso W, Cakebread A, Heesom KJ, Lewis PA, Hodson DJ, Briant LJ, Fung ACH, Sessions RB, Alpy F, Kong APS, Benke PI, Torta F, Teo AKK, Leclerc I, Solimena M, Wigley DB, Rutter GAet al., 2020, The type 2 diabetes gene product STARD10 is a phosphoinositide binding protein that controls insulin secretory granule biogenesis, Publisher: Cold Spring Harbor Laboratory

<jats:title>Abstract</jats:title><jats:sec><jats:title>Objective</jats:title><jats:p>Risk alleles for type 2 diabetes at the<jats:italic>STARD10</jats:italic>locus are associated with lowered<jats:italic>STARD10</jats:italic>expression in the β-cell, impaired glucose-induced insulin secretion and decreased circulating proinsulin:insulin ratios. Although likely to serve as a mediator of intracellular lipid transfer, the identity of the transported lipids, and thus the pathways through which STARD10 regulates β-cell function, are not understood. The aim of this study was to identify the lipids transported and affected by STARD10 in the β-cell and its effect on proinsulin processing and insulin granule biogenesis and maturation.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We used isolated islets from mice deleted selectively in the β-cell for<jats:italic>Stard10</jats:italic>(β<jats:italic>StarD10</jats:italic>KO) and performed electron microscopy, pulse-chase, RNA sequencing and lipidomic analyses. Proteomic analysis of STARD10 binding partners was executed in INS1 (832/13) cell line. X-ray crystallography followed by molecular docking and lipid overlay assay were performed on purified STARD10 protein.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>β<jats:italic>StarD10</jats:italic>KO islets had a sharply altered dense core granule appearance, with a dramatic increase in the number of “rod-like” dense cores. Correspondingly, basal secretion of proinsulin was increased. Amongst the differentially expressed genes in β<jats:italic>StarD10</jats:italic>KO islets, expression of the phosphoinositide binding proteins<jats:italic>Pirt</jats:italic>and<jats:italic>Synaptotagmin 1</jats:

Working paper

Bhatt PS, Sam AH, Meeran KM, Salem Vet al., 2019, The relevance of cortisol co-secretion from aldosterone-producing adenomas, Hormones (Athens, Greece), Vol: 18, Pages: 307-313, ISSN: 1109-3099

AIMS AND OBJECTIVES: Adrenal adenomas are usually non-functioning, but can secrete aldosterone or cortisol. It has recently been suggested that many more adenomas than previously thought secrete more than one hormone. This has important implications for their clinical management. Our aim was to determine the frequency of cortisol co-secretion in primary hyperaldosteronism at our institution and investigate the difference in metabolic profiles and clinical outcomes between co-secreting and non-co-secreting patients. DESIGN AND PATIENTS: A retrospective study of 25 patients with primary hyperaldosteronism who also underwent formal dexamethasone suppression tests to determine cortisol co-secretion. MEASUREMENTS: Post-dexamethasone suppression test cortisol, serum ALT, total cholesterol, HDL-cholesterol, LDL-cholesterol, HbA1C (were recorded) and mean arterial pressure are reported in this cohort of patients with primary hyperaldosteronism. RESULTS: Four out of 25 patients with primary hyperaldosteronism failed dexamethasone suppression tests. This suggests a frequency of co-secretion ranging between 4 and 16%. No significant difference was found in serum ALT, total cholesterol, serum HDL-cholesterol, LDL-cholesterol and mean arterial blood pressure at presentation between co-secretors and non-co-secretors. CONCLUSION: A frequency range of 4-16% suggests that a significant proportion of patients with primary hyperaldosteronism co-secrete cortisol. Co-secretors did not have a worse metabolic profile than non-secretors. The impact of co-secretion on metabolic profile and surgical management remains unclear and warrants further study.

Journal article

Salem V, Delgadillo Silva L, Suba K, Mousavy Gharavy SN, Akhtar N, Martin-Alonso A, Gaboriau DCA, Rothery SM, Styliandes T, Carrat G, Pullen TJ, Pal Singh S, Hodson DJ, Leclerc I, Shapiro AMJ, Marchetti P, Briant LB, Distaso W, Ninov N, Rutter G, Georgiadou Eet al., 2019, Leader β-cells coordinate Ca2+ dynamics across pancreatic islets in vivo, Nature Metabolism, Vol: 1, Pages: 615-629, ISSN: 2522-5812

Pancreatic β-cells form highly connected networks within isolated islets. Whether this behaviour pertains to the situation in vivo, after innervation and during continuous perfusion with blood, is unclear. In the present study, we used the recombinant Ca2+ sensor GCaMP6 to assess glucose-regulated connectivity in living zebrafish Danio rerio, and in murine or human islets transplanted into the anterior eye chamber. In each setting, Ca2+ waves emanated from temporally defined leader β-cells, and three-dimensional connectivity across the islet increased with glucose stimulation. Photoablation of zebrafish leader cells disrupted pan-islet signalling, identifying these as likely pacemakers. Correspondingly, in engrafted mouse islets, connectivity was sustained during prolonged glucose exposure, and super-connected ‘hub’ cells were identified. Granger causality analysis revealed a controlling role for temporally defined leaders, and transcriptomic analyses revealed a discrete hub cell fingerprint. We thus define a population of regulatory β-cells within coordinated islet networks in vivo. This population may drive Ca2+ dynamics and pulsatile insulin secretion.

Journal article

Salem V, Suba K, Alonso AM, Chabosseau PL, Georgiadou E, Stylianides T, Briant L, Hodson D, Carrat G, Leclerc I, Gaboriau DC, Rothery SM, Rutter GAet al., 2019, Real-Time In Vivo Imaging of Whole Islet Ca2+Dynamics Reveals Glucose -Induced Changes in Beta-Cell Connectivity in Mouse and Human Islets, 79th Scientific Sessions of the American-Diabetes-Association (ADA), Publisher: AMER DIABETES ASSOC, ISSN: 0012-1797

Conference paper

Rahman S, Salem V, Sangster A, Dunbar J, Arkle T, Bloomfield L, Bravis Vet al., 2019, Do tissue cultures add useful microbial information that changes diabetic foot ulcers management and outcome?, Publisher: WILEY, Pages: 126-126, ISSN: 0742-3071

Conference paper

Dorman E, Salem V, Valabhji J, Bravis Vet al., 2019, Conservative management of diabetic foot ulceration complicated by underlying osteomyelitis, Publisher: WILEY, Pages: 128-128, ISSN: 0742-3071

Conference paper

Salem V, Delgadillo L, Suba K, Georgiadou E, Kalogianni V, Marchetti P, Hodson D, Distaso W, Ninov N, Rutter GAet al., 2019, 3-dimensional pancreatic beta cell Ca2+ dynamics in vivo: Hub cells dictate connectivity and glucose responsivity, Publisher: WILEY, Pages: 22-22, ISSN: 0742-3071

Conference paper

Hirani D, Salem V, Bravis V, 2019, Conservative management of diabetic foot ulceration: Healing, amputation rates and deaths in non-heel and heel wounds presenting to a central London multidisciplinary diabetes foot service, Publisher: WILEY, Pages: 125-125, ISSN: 0742-3071

Conference paper

Salem V, Suba K, Martin Alonso A, Delgadillo Silva LF, Akhtar N, Mousavy N, Georgiadou E, Gaboriau D, Rothery S, Stylianides T, Marchetti P, Briant L, Ninov N, Hodson D, Distaso W, Rutter Get al., 2018, Glucose regulates pancreatic [beta] cell Ca2+ dynamics and connectivity in vivo in the anterior chamber of the mouse eye, Society for Endocrinology - British Endocrine Societies 2018, ISSN: 1470-3947

Conference paper

Comninos A, Demetriou L, Wall M, Shah A, Clarke S, Narayanaswamy S, Nesbitt A, Izzi-Engbeaya C, Prague J, Abbara A, Ratnasabapathy R, Yang LY, Salem V, Nijher G, Jayasena C, Tanner M, Bassett P, Mehta A, McGonigle J, Rabiner E, Bloom S, Dhillo Wet al., 2018, Modulations of human resting brain connectivity by Kisspeptin enhance sexual and emotional Functions, JCI insight, Vol: 3, Pages: 1-11, ISSN: 2379-3708

BACKGROUND. Resting brain connectivity is a crucial component of human behavior demonstrated by disruptions in psychosexual and emotional disorders. Kisspeptin, a recently identified critical reproductive hormone, can alter activity in certain brain structures but its effects on resting brain connectivity and networks in humans remain elusive.METHODS. We determined the effects of kisspeptin on resting brain connectivity (using functional neuroimaging) and behavior (using psychometric analyses) in healthy men, in a randomized double-blinded 2-way placebo-controlled study.RESULTS. Kisspeptin’s modulation of the default mode network (DMN) correlated with increased limbic activity in response to sexual stimuli (globus pallidus r = 0.500, P = 0.005; cingulate r = 0.475, P = 0.009). Furthermore, kisspeptin’s DMN modulation was greater in men with less reward drive (r = –0.489, P = 0.008) and predicted reduced sexual aversion (r = –0.499, P = 0.006), providing key functional significance. Kisspeptin also enhanced key mood connections including between the amygdala-cingulate, hippocampus-cingulate, and hippocampus–globus pallidus (all P < 0.05). Consistent with this, kisspeptin’s enhancement of hippocampus–globus pallidus connectivity predicted increased responses to negative stimuli in limbic structures (including the thalamus and cingulate [all P < 0.01]).CONCLUSION. Taken together, our data demonstrate a previously unknown role for kisspeptin in the modulation of functional brain connectivity and networks, integrating these with reproductive hormones and behaviors. Our findings that kisspeptin modulates resting brain connectivity to enhance sexual and emotional processing and decrease sexual aversion, provide foundation for kisspeptin-based therapies for associated disorders of body and mind.

Journal article

Salem V, Silva LD, Suba K, Akhtar N, Mousavy N, Martin-Alonso A, Georgiadou E, Gaboriau DCA, Rothery SM, Stylianides T, Hodson DJ, Marchetti P, Briant L, Ninov N, Rutter GAet al., 2018, Glucose regulates pancreatic islet beta cell calcium dynamics and intercellular connectivity in vivo, 54th Annual Meeting of the European-Association-for-the-Study-of-Diabetes (EASD), Publisher: SPRINGER, Pages: S18-S18, ISSN: 0012-186X

Conference paper

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