Now showing items 1-20 of 275

    • Surface Stability in Drylands is Influenced by Dispersal Strategy of Soil Bacteria

      Elliott, David R.; Thomas, Andrew D.; Strong, Craig L.; Bullard, Joanna; Environmental Sustainability Research Centre, University of Derby (American Geophysical Union (AGU), 2019-10-09)
      Microbial adaptations for survival and dispersal may directly influence landscape stability and potential for dust emission in drylands where biological soil crusts (biocrusts) protect mineral soil surfaces from wind erosion. In the Lake Eyre basin of central Australia we operated a wind tunnel on sandy soils and collected the liberated material, which was subjected to DNA sequencing to identify the microbial community composition. Microbial composition of entrained dust was compared with that of the source sand dune soil in addition to nearby claypan and nebkha soils, and water channels which together form a recycling sediment transport system. Wind was found to preferentially liberate 359 identified taxa from sand dunes whereas 137 identified taxa were found to resist wind erosion. Water channel communities included many taxa in common with the soil samples. We hypothesise that the ease with which soil microbes become airborne is often linked to whether the organism is adapted for dispersal by wind or vegetative growth, and that biocrust organisms found in water channels may sometimes use a fluvial dispersal strategy which exploits rare flooding events to rapidly colonise vast pans which are common in drylands. We explain likely geomorphic implications of microbial dispersal strategies which are a consequence of organisms engineering the environment to provide their particular needs. By identifying microbes fitting expectations for these dispersal strategies based on differential abundance analyses, we provide a new perspective for understanding the role of microbiota in landscape stability.
    • Accelerometer-based physical activity levels differ between week and weekend ways in British preschool children

      Roscoe, Clare M. P.; James, Rob S.; Duncan, Michael J.; University of Derby; Coventry University (MDPI AG, 2019-09-12)
      Participation in physical activity (PA) is fundamental to children’s future health. Studies examining the temporal pattern of PA between weekdays and weekends in British preschool children are lacking. Therefore, the aim of this study was to compare PA levels between week and weekend days for UK preschool children, using objective measurements. One hundred and eighty-five preschool children (99 boys, 86 girls, aged 4–5 years), from central England wore a triaxial accelerometer (GENEActiv) for 4 days to determine PA. The time (min) and percentage (%) of time spent in light, moderate and vigorous PA (MVPA) was determined using specific cut-points for counts per minute related to 3–5 year olds. Of the sample, none of the children met the UK recommended 180 min or more of PA per day. A significant difference (P < 0.05) was observed between the amount of time that preschool children spent in sedentary behaviours on weekdays (91.9%) compared to weekend days (96.9%). During weekdays and weekend days, 6.3% and 2.0% of time was spent in MVPA, respectively. Therefore, a substantial proportion of British preschool children’s day is spent in sedentary behaviours, with less MVPA accrued during the weekend. Regular engagement during the weekdays provides opportunities to accrue PA, which may not be present on weekend days.
    • Do individuals with Chronic Pain show attentional bias to pain-related information? An early stage systematic review of the eye-tracking evidence.

      Gaffiero, Daniel; Elander, James; Maratos, Frances; University of Derby (British Psychology Society, 2019-03)
    • Basaltic maar-diatreme volcanism in the Lower carboniferous of the Limerick Basin (SW Ireland)

      Gernon, T. M.; Roberts, S.; Hewson, C.; Elliott, Holly; University of Southampton (Springer, 2015-04-16)
      Lead-zinc exploration drilling within the Limerick Basin (SW Ireland) has revealed the deep internal architecture and extra-crater deposits of five alkali-basaltic maar-diatremes. These were emplaced as part of a regional north-east south-west tectonomagmatic trend during the Lower Carboniferous Period. Field relationships and textural observations suggest that the diatremes erupted into a shallow submarine environment. Limerick trace element data indicates a genetic relationship between the diatremes and extra-crater successions of the Knockroe Formation, which records multiple diatreme filling and emptying cycles. Deposition was controlled largely by bathymetry defined by the surrounding Waulsortian carbonate mounds. An initial non-diatreme forming eruption stage occurred at the water-sediment interface, with magma-water interaction prevented by high magma ascent rates. This was followed by seawater incursion and the onset of phreatomagmatic activity. Magma-water interaction generated poorly vesicular blocky clasts, although the co-occurrence of plastically deformed and highly vesicular clasts indicate that phreatomagmatic and magmatic processes were not mutually exclusive. At a later stage, the diatreme filled with a slurry of juvenile lapilli and country rock lithic clasts, homogenised by the action of debris jets. The resulting extra-crater deposits eventually emerged above sea level, so that water ingress significantly declined, and late-stage magmatic processes became dominant. These deposits, largely confined to the deep vents, incorporate high concentrations of partially sintered globular and large ‘raggy’ lapilli showing evidence for heat retention. Our study provides new insights into the dynamics and evolution of basaltic diatremes erupting into a shallow water (20–120 m) submarine environment.
    • The significance of metasomatic alteration surrounding carbonatite complexes as a REE-enrichment indicator

      Broom-Fendley, S.; Wall, F.; Elliott, Holly; University of Exeter (Taylor and Francis, 2019-07-24)
    • Diatremes act as fluid conduits for Zn-Pb mineralization in the SW Irish Ore field

      Gernon, Thomas M.; Roberts, Stephen; Boyce, Adrian J.; Hewson, Chad; Elliott, Holly; University of Southampton (GeoScienceWorld, 2019-02-28)
      Irish-type mineralization is commonly attributed to fault-controlled mixing of a seawater-derived, sulfur-rich fluid and basement-derived, metal-rich fluid. However, maar-diatreme volcanoes discovered in close spatial and temporal association with Zn-Pb mineralization at Stonepark in the Limerick basin (southwest Ireland) bring a new dimension to established geologic models and may increase the deposit-scale prospectivity in one of the world’s greatest Zn-Pb districts. Stonepark exhibits many incidences of dolomitic black matrix breccias with associated Zn-Pb mineralization, the latter typically occurring within 150 m of the diatremes. Highly negative δ34S pyrite values within country rock-dominated black matrix breccias (–12 to –34‰) are consistent with sulfide precipitation from bacteriogenic sulfur reduction in seawater-derived brines. However, δ34S values of Zn-Pb sulfides replacing black matrix breccias (–10 to 1‰) reflect multiple sulfur sources. Diatreme emplacement both greatly enhanced country rock fracture permeability and produced conduits that are filled with porous volcaniclastic material and extend down to basement rock types. Our δ34S data suggest that diatremes provide more efficient fluid pathways for basement-derived fluids. The diatremes introduce another potential sulfur source and facilitate a greater input of metal-rich basement-derived hydrothermal fluid into the system compared to other Irish-type deposits such as Navan and Lisheen, evidenced by Stonepark’s more positive modal δ34S value of –4‰. Irish-type deposits are traditionally thought to form in association with extensional basement faults and are considered unrelated to extensive Carboniferous magmatism. Our results indicate that a direct link exists between diatreme volcanism and Zn-Pb mineralization at Limerick, prompting a reevaluation of the traditional Irish-type ore formation model, in regions where mineralization is spatially associated with volcanic pipes.
    • Treating hoarding disorder with compassion‐focused therapy: A pilot study examining treatment feasibility, acceptability, and exploring treatment effects

      Chou, Chia‐Ying; Tsoh, Janice Y.; Shumway, Martha; Smith, Lauren C.; Chan, Joanne; Delucchi, Kevin; Tirch, Dennis; Gilbert, Paul; Mathews, Carol A.; Department of Psychiatry, University of California, San Francisco, California, USA; et al. (Wiley Online Library, 2019-07-04)
      Hoarding disorder (HD) was recognized as a psychiatric disorder in 2013. Existing literature suggests room for improvement in its treatment. The current pilot study aimed to provide an initial evaluation on the potential of compassion‐focused therapy (CFT) as an intervention for HD, with the primary aim being assessing its feasibility and acceptability, and the secondary being evaluating its effects. Both CFT and a second round of the current standard of treatment and cognitive behavioural therapy (CBT) were investigated in the current study as follow‐up treatment options for individuals who had completed CBT but were still significantly symptomatic. Forty eligible individuals were enrolled (20 in each treatment). Treatment feasibility and acceptability were assessed by quantitative and qualitative measures. To explore treatment effects, HD symptom severity, HD‐related dysfunctions, and their underlying mechanisms were assessed pre‐treatment and post‐treatment. Retention rates were 72% for CFT and 37% for CBT. All participants and 79% of the participants rated CFT and CBT, respectively, as good or excellent. After receiving CFT as a follow‐up treatment, HD symptom severity dropped below the cut‐off point for clinically significant HD for 77% of the treatment completers, and 62% achieved clinically significant reduction in symptom severity. In contrast, after completing a second course of CBT, 23% had HD symptom severity dropped below the cut‐off threshold, and 29% achieved clinically significant symptom reduction. The current study showed satisfactory feasibility and acceptability of CFT. Moreover, it also found promising effects of CFT in addressing hoarding‐related mechanisms that may not have been sufficiently addressed by CBT. The results suggest promising potential of CFT as a treatment for HD. Further investigation on this intervention is needed. CFT may be a promising treatment option, particularly for those who do not respond well to CBT. Improving emotion regulation and negative self‐perception by applying CFT interventions may help relieve hoarding symptoms. Generalization of the findings should be applied with caution given the small convenience sample of the current study. Statistical comparison on treatment effect measures between CFT and CBT as follow‐up treatments was not available due to small sample size. Therefore, the comparative conclusions based on this pilot study should be made with caution.
    • Fenites associated with carbonatite complexes: A review

      Wall, F.; Chakhmouradian, A.R.; Siegfried, P.R.; Dahlgren, S.; Weatherley, S.; Finch, A.A.; Marks, M.A.W.; Dowman, E.; Deady, E.; Elliott, Holly; et al. (Elsevier, 2017-12-11)
      Carbonatites and alkaline-silicate rocks are the most important sources of rare earth elements (REE) and niobium (Nb), both of which are metals imperative to technological advancement and associated with high risks of supply interruption. Cooling and crystallizing carbonatitic and alkaline melts expel multiple pulses of alkali-rich aqueous fluids which metasomatize the surrounding country rocks, forming fenites during a process called fenitization. These alkalis and volatiles are original constituents of the magma that are not recorded in the carbonatite rock, and therefore fenites should not be dismissed during the description of a carbonatite system. This paper reviews the existing literature, focusing on 17 worldwide carbonatite complexes whose attributes are used to discuss the main features and processes of fenitization. Although many attempts have been made in the literature to categorize and name fenites, it is recommended that the IUGS metamorphic nomenclature be used to describe predominant mineralogy and textures. Complexing anions greatly enhance the solubility of REE and Nb in these fenitizing fluids, mobilizing them into the surrounding country rock, and precipitating REE- and Nb-enriched micro-mineral assemblages. As such, fenites have significant potential to be used as an exploration tool to find mineralized intrusions in a similar way alteration patterns are used in other ore systems, such as porphyry copper deposits. Strong trends have been identified between the presence of more complex veining textures, mineralogy and brecciation in fenites with intermediate stage Nb-enriched and later stage REE-enriched magmas. However, compiling this evidence has also highlighted large gaps in the literature relating to fenitization. These need to be addressed before fenite can be used as a comprehensive and effective exploration tool.
    • Complex subvolcanic magma plumbing system of an alkali basaltic maar-diatreme volcano (Elie Ness, Fife, Scotland)

      Upton, B.G.J.; Ugra, R.; Yücel, C.; Taylor, R.N.; Elliott, Holly; University of Southampton (Elsevier, 2016-08-17)
      Alkali basaltic diatremes such as Elie Ness (Fife, Scotland) expose a range of volcanic lithofacies that points to a complex, multi-stage emplacement history. Here, basanites contain phenocrysts including pyrope garnet and sub-calcic augites from depths of ~60km. Volcanic rocks from all units, pyroclastic and hypabyssal, are characterised by rare earth element (REE) patterns that show continuous enrichment from heavy REE (HREE) to light REE (LREE), and high Zr/Y that are consistent with retention of garnet in the mantle source during melting of peridotite in a garnet lherzolite facies. Erupted garnets are euhedral and unresorbed, signifying rapid ascent through the lithosphere. The magmas also transported abundant pyroxenitic clasts, cognate with the basanite host, from shallower depths (~35–40km). These clasts exhibit wide variation in texture, mode and mineralogy, consistent with growth from a range of compositionally diverse melts. Further, clinopyroxene phenocrysts from both the hypabyssal and pyroclastic units exhibit a very wide compositional range, indicative of polybaric fractionation and magma mixing. This is attributed to stalling of earlier magmas in the lower crust — principally from ~22 to 28km — as indicated by pyroxene thermobarometry. Many clinopyroxenes display chemical zoning profiles, occasionally with mantles and rims of higher magnesium number (Mg#) suggesting the magmas were mobilised by juvenile basanite magma. The tuffs also contain alkali feldspar megacrysts together with Fe-clinopyroxene, zircon and related salic xenoliths, of the ‘anorthoclasite suite’ — inferred to have crystallised at upper mantle to lower crustal depths from salic magma in advance of the mafic host magmas. Despite evidence for entrainment of heterogeneous crystal mushes, the rapidly ascending melts experienced negligible crustal contamination. The complex association of phenocrysts, megacrysts and autoliths at Elie Ness indicates thorough mixing in a dynamic system immediately prior to explosive diatreme-forming eruptions.
    • PWE-001 field cancerisation theory in colorectal cancer (crc): what role do fibroblast growth factors have?

      Patel, A; Williams, N; Nwokolo, C; Tripathi, G; Arasaradnam, R; University of Westminster (BMJ, 09/06/2014)
      Characterisation of the molecular field defect around colorectal cancer (CRC) could enable identification of novel biomarkers that could be used for early detection of CRC. Previous studies have suggested fibroblast growth factor 19 (FGF19) may play a role in CRC formation through interaction with the B-catenin/wnt signalling cascade. The role of fibroblast growth factor 7 (FGF7) however remains controversial. The aim of this study was to determine if there are differences in FGF19 and FGF7 gene expression in cancer tissue and the adjacent ‘normal tissue’ compared with normal colonic tissue. Mucosal pinch biopsies were taken from the rectum and caecum at time of colonoscopy for healthy controls. For CRC patients, tissue samples were taken from the tumour, adjacent to the tumour and at the resection margin of the colectomy specimen. Healthy controls were age and sex matched to CRC patients. Quantitative real time PCR was used to determine gene expression of FGF19, its receptor FGFR4, FGF7 and its receptor, FGFR2. Results were further validated using immunohistochemistry. Serum levels of FGF19 were measured using the Quantikine ELISA kit (RandD systems, UK). 49 patients were recruited (28 M: 21 F, median age 71 years (range 48–86 years)); 18 patients with CRC and 32 healthy controls. There was no overall difference in gene expression of FGF19/FGFR4 or FGF7/FGFR2 between cancer patients and healthy controls. There was upregulation of FGFR4 in mucosa adjacent to the tumour (mean fold change 1.23 vs. 0.93, p = 0.38) and the tumour itself (mean fold change 1.49 vs. 1.04, p = 0.700) in patients whose tumour expressed FGF19 compared to those that did not. Patients with upregulation of FGF19/FGFR4 had a significantly lower fasting serum FGF19 level (119 pg/ml versus 208 pg/ml, p = 0.05). FGF7 was upregulated in 6/19 cancers; this was associated with a significant upregulation in FGF7 in adjacent mucosa compared with cancers where FGF7 was downregulated (mean fold change 3.62 vs. 0.95, p = 0.018). There was a non-significant trend towards upregulation of the receptor (FGFR2) in mucosa adjacent to the cancer and the tumour tissue itself. Upregulation of FGFR4 in patients whose tumours expressed FGF19 corresponded inversely with serum FGF19 suggesting its potential as a putative biomarker. Significant upregulation of FGF7 in ‘normal’ mucosa adjacent to only tumours that express FGF7 lends support to the field theory of colorectal carcinogenesis.
    • Systemic triglycerides as a key determinant of TLR regulated inflammatory risk in human adipose tissue post bariatric surgical intervention and weight loss

      Kumsaiyai, W; Al-Daghri, N; Kyrou, I; Vrbikova, J; Hainer, V; Fried, M; Sramkova, P; Barber, T; S Kumar; Tripathi, G; et al. (bioscientifica, 01/03/2014)
      Bariatric surgery can lead to a quick reversal in type 2 diabetes mellitus (T2DM) status. However, despite this reversal inflammatory responses may still persist via activation of Toll-like receptors (TLR) within adipose tissue (AT); with triglycerides (TGs) noted as a potential mediator of such inflammation. Therefore the aims of these studies were to understand the impact of TG changes, pre- and post-bariatric surgery, on TLR expression in ex vivo AT and the in vitro effects of triglyceride rich lipoprotein (VLDL), on TLR expression in isolated human differentiated pre-adipocytes. Obese, T2DM, female subjects (age: 54.6±6.6 years, BMI pre (41.2±5.5 kg/m2) and 6 months post-surgery (36.05±5.16 kg/m2; n=30) underwent bariatric surgery (banding (n=8); plication (n=14); and biliopancreatic diversion (n=8)). Biochemical data and abdominal subcutaneous AT (AbdSc AT) samples were taken during surgery and 6 months post-surgery. Real-time PCR assessed TLR expression. Human differentiated pre-adipocyte Chub S7 cells were used to examine transcriptional effects of VLDL on TLR expression. Following surgical intervention, BMI (P<0.001), blood glucose (P<0.001), insulin (P<0.001), HOMA-IR (P<0.001), TG (P<0.05), cholesterol (P<0.001), and LDL-cholesterol (P<0.05) were significantly improved. There was a significant reduction in TLR4 mRNA post-surgery (P<0.01) irrespective of surgery type. It was also noted that subjects with the greatest drop (55.5% reduction) in TGs post-surgery (P<0.001) showed a significant correlated reduction in TLR4 mRNA expression (P<0.001). In vitro treatment of differentiated Chub S7 cells highlighted VLDL induced TLR4 mRNA expression (P<0.05).There is a reduction in AT inflammation as denoted by TLR expression. The reduction in AT inflammation appears dependent on how successfully subjects reduce their serum triglyceride, which is supported by in vitro studies. These studies suggest that bariatric surgery lead to metabolic improvement with weight loss, whilst dietary intervention is still required to ensure TGs reduce to reduce inflammation.
    • Meal size and frequency influences metabolic endotoxaemia and inflammatory risk but has no effect on diet induced thermogenesis in either lean or obese subjects

      Piya, M; Reddy, N; Campbell, A; Hattersley, J; Halder, L; Tripathi, G; Tahrani, A; Kumar, S; Barber, T; McTernan, P; et al. (bioscientifica, 01/03/2014)
      Small frequent meals are often recommended for weight loss, with supporting evidence often provided from studies in diabetes. Dietary meal content is also relevant, as high fat meals cause systemic inflammation via gut derived bacteria, endotoxin. As such, repeated meals may exacerbate this. In contrast, dietary induced thermogenesis, related to meal size, may reduce with small frequent meals. Therefore, the aim of this study was to compare the effect of 2 vs 5 meals on metabolic endotoxaemia and 24 h (hour) energy expenditure in lean and obese women. In a crossover study, 24 lean (age: 34 (mean±S.D.)±10 years, BMI: 22.9±2 kg/m2) and obese (age: 42±9 years, BMI: 36±8 kg/m2) women were given two or five isocaloric high (50%) fat meals, on two separate days. On both visits, 24 h energy expenditure was measured in whole body room calorimeters and blood samples taken 2 hourly (0900 to 2100 h). Serum endotoxin, glucose, insulin, lipids were measured. The obese subjects had increased area under the curve (AUC) for insulin, glucose, HOMA-IR and triglyceride (TG), with decreased HDL (P<0.01), compared with lean subjects, for both meal visits. For the entire cohort, fasting endotoxin correlated with triglyceride (r=0.32, P<0.05), and AUC for endotoxin and TG correlated in the five meal visit (r=0.44, P<0.05), but not the two meal visit. In the final 2100 h blood test, the endotoxin levels were significantly higher in the five meal visit (P=0.05), but not the two meal visit. Meal frequency did not affect 24 h expenditure, in either the obese group (2124±312 vs 2142±365 Kcal/day) or lean group (1724±160 vs 1683±166 Kcal/day).Our findings suggest in metabolically healthy lean and obese subjects, increased meal frequency may pose an inflammatory risk posed by circulating endotoxin and TGs leading to peak levels at bedtime. As such, small frequent meals may not influence diet induced thermogenesis, but may increase metabolic disease risk.
    • Unfolded protein response in adipose tissue of obese diabetic women significantly improved 6 months post bariatric surgery, irrespective of malabsorptive or bypass operation type and correlates with plasma glucose concentration

      Voyias, P; Antonysunil, A; Kumasaiyai, W; Kyrou, I; Vrbikova, J; Hainer, V; Fried, M; Sramkova, P; Saravanan, P; Kumar, S; et al. (bioscientifica, 01/03/2014)
      In obesity, excess nutrients and an increased demand for protein synthesis contribute to unfolded proteins accumulating within the endoplasmic reticulum and consequent activation of unfolded protein response (UPR). UPR in adipose tissue (AT) is critical to the initiation and integration of inflammation and insulin signalling pathways in obese and type 2 diabetes mellitus (T2DM) patients. The aim of this study was to examine whether novel malabsorptive or bypass bariatric surgery in obese women with T2DM leads to reduction in UPR. Abdominal subcutaneous (AbSc) AT was isolated from 30 Caucasian obese T2DM women aged 54.1±1.3 (mean±S.E.M.) years, BMI 41.21±1.0 kg/m2, that had undergone bariatric surgery of malabsorptive; gastric band (n=9) or novel gastric plication (n=13), or bypass; biliopancreatic diversion (n=8) type. Biopsies and anthropometric data were collected at the time of surgery and 6 months post-surgery. UPR markers were measured by qRT-PCR and western blotting and correlation analysis was performed. Six months post-operation all subjects significantly reduced body weight (P<0.001) with mean excess BMI lost 33.4±2.4%. Anthropometric measurements were significantly improved; fat mass, HbA1c, glucose, insulin, HOMA-IR, and total cholesterol (all P<0.001). ATF6, IRE1α, XBP1s, ATF4, and CHOP10 mRNAs and ATF6, pIRE1α, XBP1s, Calnexin and Bip proteins were all significantly (P<0.05) reduced post-surgery irrespective of operation type. Correlations between UPR mRNAs were strengthened post-surgery for ATF4 and CHOP10 (P=0.041–P<0.001) and IRE1α and ATF6 (P=0.853–P<0.001). Post-surgery plasma glucose correlated significantly (P=0.034) with XBP1s mRNA. This study highlights that bariatric surgery induced weight loss is coupled with improved glucose homeostasis and reduced UPR expression in AT. Furthermore post weight loss there are enhanced associations identified between UPR and XBP1 in AT and plasma glucose which may arise due to improved glucose homeostasis. This suggests UPR regulation in AT is linked to plasma glucose levels which aligns to metabolic health.
    • A 3-month low fat diet leads to significant lipid profile improvement in obese T2DM Saudi subjects, without substantial weight loss, and the capacity to manage a damaging high-fat meal challenge more appropriately post intervention

      Al-Disi, D; Al-Daghri, N; Khan, N; Alsaif, M; Alfadda, A; Sabico, S; Tripathi, G; McTernan, P; University of Westminster (bioscientifica, 01/03/2014)
      Current evidence highlights that dietary cholesterol, trans-fatty acids and saturated fatty acids (SFAs) are all known to increase the levels of systemic atherogenic lipoproteins and cardiovascular disease. The aim of this study was to observe the direct effect of dietary change, via a calorie-restricted diet on i) cardio-metabolic profile and ii) a high-fat meal challenge pre- and post-3-month intervention. T2DM subjects (Saudi female, age: 40.50±6.8years, BMI: 37.28±10.75 kg/m2, n=18) were given a high-fat meal pre- and post-calorie restricted diet (3 months; 500 kcal deficit/day, balanced diet with complex carbohydrate). Baseline (0 h) and post-prandial sera (1–4 h) were taken from subjects, anthropometric and biochemical data was collated at both time points. On baseline comparison of pre- and post-diet interventions, there were modest reductions in anthropometric data, BMI (P<0.001), waist (P<0.001), and waist:hip ratio (WHR; P<0.01). Baseline HDL-cholesterol increased significantly (P<0.01) whilst LDL- and total-cholesterol were significantly reduced (pre-total cholesterol: 5.13 (4.53, 5.93) vs post-total cholesterol: 4.70 (4.01, 5.14); pre-LDL cholesterol: 3.56 (3.07, 4.06) vs post-LDL cholesterol: 2.81 (2.34, 3.56), P<0.05). The findings also showed significant changes in the effects of high-fat meal intake on the metabolic profile pre- and post-diet intervention. At 4 h post-prandially, post-dietary intervention, HDL-cholesterol was 16.6% higher than pre-diet (P<0.05), whilst LDL- and total-cholesterol were 24.2 and 12% lower, respectively, than at the 4 h equivalent pre-diet (P<0.05). These findings suggest that lipid mediators associated with increased cardiometabolic risk can be quickly reversed as a result of a balanced diet, in T2DM subjects without substantial weight loss. As a result, the body is able to cope with the occasional high-fat meal insult, whilst still maintaining a reduced long-term CVD risk. As such, this is a diet that patients with T2DM may be able to adhere to more successfully, longer-term.
    • Vitamin B12 deficiency induces cholesterol biosynthesis by limiting S-adenosyl methionine and altering the methylation of Srebf1 and Ldlr genes

      Adaikalakoteswari, A; Finer, S; Voyias, P.D; McCarthy, C; Moore, J; Smart-Halajko, M; Bawazeer, N; Al-Daghri, N.M; McTernan, P.G; University of Westminster
      Maternal vitamin B12 deficiency affecting one-carbonmetabolism influences metabolic status and the degree of insulinresistance of the offspring in adulthood. But its significance andmechanism in the development of adiposity and adipose tissuedysfunction is unknown. To investigate the role of vitamin B12 in the developmentof adipocyte dysfunction. Human pre-adipocytes were differentiatedin customised media with varying concentrations of B12. Adipo-cytes cultured in low B12 (0.15nM) or no B12 conditions hadincreased cholesterol and homocysteine levels and reduced glucoseuptake capacity compared to control (B12 500nM). Global DNAmethylation profiling and bisulphite pyrosequencing showed thatthe promoter regions of sterol regulatory element-binding tran-scription factor 1 (SREBF1) and low density lipoprotein receptor(LDLR) were hypomethylated in B12 deficient conditions, consis-tent with the increased gene expressions. The S-adenosyl methio-nine/S-adenosyl homocysteine ratio was significantly lower in B12deficient conditions. Inhibition of methylation in high B12 condi-tions by 5-aza-2-deoxycytidine led to increased cholesterol accu-mulation but not homocysteine. In two independent clinicalstudies, women at child bearing age (age: 19–39 years) and inearly pregnancy (16–18 weeks), showed that low B12 was asso-ciated with higher total cholesterol, LDL cholesterol and choles-terol to HDL ratio. Regression analysis in the pregnant cohortadjusting for all confounders showed B12 levels to be indepen-dently associated with total cholesterol and triglyceride levels. Vitamin B12 deficiency leads to adipocyte dysfunc-tion by inducing cholesterol biosynthesis and homocysteine.Induction of cholesterol biosynthesis was due to hypomethylationof SREBF1 and LDLR. Clinical observations support that the B12effect is independent and our findings show this link is probably causal.
    • Elevated cord leptin from low B12 mothers predicts birth weight

      Antonysunil, A; Vatish, M; Lawson, A; Wood, C; Sivakumar, K; Webster, C; Anderson, N; McTernan, P; Tripathi, G; Saravanan, P; et al. (bioscientifica, 01/03/2014)
      Vitamin B12 (B12) insufficiency is common in pregnancy and independently predicts insulin resistance (IR) in the offspring. B12 is an important key nutrient for epigenetic programming through regulating DNA methylation. Such B12 DNA methylation may influence leptin, a strong candidate for methylation, which could impact both insulin resistance (IR) and associated neonatal metabolic risk. Therefore, we hypothesize that leptin can be programmed by maternal B12 which could influence metabolic risk in the offspring. To test this hypothesis, we investigated whether i) maternal B12 is associated with leptin in cord blood and ii) evaluated their association with birth weight. Paired maternal venous and cord blood samples (n=91) were collected at the time of elective caesarean section. Serum vitamin-B12 was determined by electro-chemiluminescent immunoassay. Leptin levels were measured by ELISA. B12 insufficiency (<150 pmol/l) was common (mothers-40%; and neonates-29%). Maternal B12 was inversely associated with neonatal leptin (r=−0.304; P=0.005). In regression analysis, adjusted for all likely confounders, maternal B12 independently predicted neonatal leptin (β=−0.647; P=0.005; R2=12.8%). There was no correlation between maternal and neonatal leptin levels. Cord leptin from mothers with low B12 correlated with birth weight (r=0.366; P=0.036). Regression analysis adjusted for maternal leptin and insulin showed that cord leptin from mothers with low B12 independently predicted birth weight (β=0.024; P=0.049; R2=14.5%). Our study highlights that maternal B12 insufficiency predicts elevated leptin in cord blood and is associated with higher birth weight. Since cord leptin is derived from neonatal adipose tissue and not mother, these findings suggest that maternal B12 might program leptin levels in-utero either directly through the satiety centre or mediated via inducing IR and adiposity in the offspring. Delineating the mechanistic relationship between cord leptin and maternal B12 might provide crucial answers in understanding the molecular mechanisms of adverse metabolic programming.
    • Freeze dried broccoli extract relieves ER stress and mitochondrial inefficiency in differentiated human pre-adipocyte cells

      Murphy, A; Jackisch, L.; Azharian, S; Aladel, A; Barker, G; Tripathi, G; Chappell, M; McTernan, P; University of Westminster (bioscientifica, 01/03/2014)
      In obesity, excess nutrients can disrupt protein folding in the endoplasmic reticulum (ER) which activates the unfolded protein response (UPR) and alters mitochondrial function. These changes can induce inflammation, oxidative stress and insulin resistance. The aim of the study was to investigate whether broccoli extract can protect against cellular damage in human adipocytes, which with mathematical modelling may help predict pathway response. Differentiated Chub-S7 cells were treated over a 72 hr time course with 10 ng/ml freeze-dried broccoli extract (hybrid Brassica oleracea var. italic) alone or combined with ER stress inducer, tunicamycin (750 ng/ml). UPR markers (ATF6, ATF4, CHOP, ERO1α, P-PERK, PERK, P-eIF2α, eIF2α, P-IRE1α and IRE1α) were measured by qRT-PCR and Western blot. Mitochondrial genes (MFN2, OPA1, UCP2, SOD2, POLG) were also measured. Mathematical modelling was undertaken. Tunicamycin led to a significant increase in UPR gene expression (P<0.05), whilst broccoli extract combined with tunicamycin significantly reduced the expression of UPR markers compared with those treated only with tunicamycin, in a time dependent manner. Tunicamycin had a detrimental effect on mitochondrial genes (P<0.05); the presence of broccoli appeared to protect against these effects. This in-vitro time-series data are being used to realistically parameterise an existing mathematical model. Broccoli extract appears to positively influence protein folding in ER stressed adipocytes, reducing UPR gene expression and causing influential changes in mitochondria. As such broccoli supplementation in the daily diet may reduce the inflammatory response posed by adipose tissue during weight gain. The mathematical model of the UPR offers the possibility of in silico optimisation for the supplementation.
    • PWE-254 Is the macroscopically normal mucosa (MNM) around colorectal cancer really ‘normal’?

      Patel, A; Fang, Y; Moore, J; Williams, N; Tripathi, G; Arasaradnam, R; University of Westminster (BMJ, 22/06/2015)
      Field cancerisation refers to the process whereby cells acquire pro-tumourigenic mutations that predispose to malignant transformation but do not produce morphological change.1Previous colorectal cancer studies have assumed that the macroscopically normal mucosa (MNM) adjacent to a cancer is biologically unaltered. The aim of this study was to determine if the genetic expression profile of the MNM around a cancer or adenoma is different to that found in healthy controls. 15 patients undergoing colonoscopy were recruited over 12 months; 5 healthy controls, 5 with colorectal adenomas and 5 with adenocarcinoma. Two mucosal pinch biopsies were taken in the rectum, right colon and adjacent to polyp or cancer. mRNA was extracted and gene expression was assessed using standard whole genome micro-array analysis. Differentially expressed genes were identified using three methods of analysis: LIMMA (fold change ratio >1.5 and p value <0.05), Robust Regression (RR) (adjusted p value <0.05) and genes that ‘overlap’ when LIMMA (p value <0.001) and RR (adjusted p value <0.1) are used. Functional analysis was performed using DAVID2software to identify important biological processes that were dysregulated. A large number of genes were dysregulated in the MNM adjacent to cancer or adenoma compared with controls (Table 1). Interestingly, the greatest differences were seen between MNM adjacent to cancer and polyp in chromatin organisation, nucleosome processing, nuclear transport and histone assembly. The most significantly upregulated genes consisted of FUT2, CTSA, MUC2 and SDS and downregulated genes consisted of GREM1, SFRP, HIST1H, IL17B and TFF1.
    • Tunicamycin-induced ER stress mediates mitochondrial dysfunction in human adipocytes

      Jackisch, L; Murphy, A; Al-Daghri, N; McTernan, P; Randeva, H; Tripathi, G; University of Westminster (bioscientifica, 01/03/2014)
      The pathogenesis of obesity and T2DM mediates mitochondrial dysfunction which, in part, may arise as a consequence of endoplasmic reticulum (ER) stress. However, the potential impact of ER stress on mitochondria dysfunction is unclear. Therefore, we investigated whether induction of ER stress contributes to mitochondrial dysfunction in human adipocytes using 1) human differentiated adipocyte cell line (Chub-S7, n=12); and 2) primary differentiated lean and obese abdominal subcutaneous adipocytes (AbdSc Ad; n=3 respectively). ER stress was induced in post-differentiated Chub-S7 (AbdSc Ad) using tunicamycin (Tn) (0.25 μg/ml, 0.75 μg/ml) for 24 hrs, 48 hrs and 72 hrs. Assessment of mitochondrial function post Tn treatment was undertaken using the Extracellular Flux Analyser – evaluating oxygen consumption rate (OCR) and proton excretion (glycolysis; extracellular acidification rates (ECAR)). Flux stressors (oligomycin, FCCP, rotenone/antimycin A) were given to Chub-S7 adipocytes treated with Tn to measure mitochondrial response. Mitochondrial dynamics were also evaluated using RT-PCR and confocal microscopy. The Seahorse stress test identified that Tn (0.25 μg/ml, 0.75 μg/ml) induced mitochondrial stress with a 14% rise in OCR (Basal: 472 pMoles/min vs Tn: 537 pMoles/min; P=0.002) and a maximum 78% increase in ECAR (Basal: 124 mpH/minute vs Tn: 228 mpH/minute; P=0.006). This Tn induced mitochondrial stress was maintained over 72 hrs. Coupled with the observed functional data, mRNA expression analysis highlighted that fission (Drp1, Fis 1; P<0.01) and fusion (Mfn2, Opa1; P<0.01) were both increased by Tn (0.25 μg/ml, 0.75 μg/ml). Confocal microscopy was used to further verify this result. These studies highlight unfavourable changes in mitochondrial function and gene expression arise in adipocytes, in response to an inducer of ER stress; this may mimick an obese phenotype. Taken together, these results indicate that therapeutics to reduce ER stress could have a beneficial influence on alleviating mitochondrial dysfunction and its pathogenic consequences.
    • Telmisartan reverses antiretroviral-induced adipocyte toxicity and insulin resistance in vitro

      Pushpakom, S.P; Adaikalakoteswari, A; Owen, A; Back, D.J; Tripathi, G; Kumar, S; McTernan, P; Pirmohamed, M; University of Warwick (Sage, 21/02/2018)
      Antiretroviral therapy in HIV-positive patients leads to insulin resistance which is central to the pathogenesis of various metabolic abnormalities and cardiovascular disease seen in this patient group. We have investigated the dose–response relationship of telmisartan, an antihypertensive, on adipocytes in vitro in order to determine whether it may have metabolic beneficial effects. Using in vitro chronic toxicity models (3T3-F442A murine and primary human adipocytes), we evaluated the effects of different concentrations of telmisartan on adipocyte differentiation and adipogenic gene expression using lipid accumulation assays and real-time polymerase chain reaction, respectively. Adipokine secretion and expression of insulin signalling mediators were evaluated using enzyme-linked immunosorbent assays. Telmisartan partially reversed the deleterious effects of antiretrovirals on adipocyte lipid accumulation, expression of adipogenic regulators (peroxisome proliferator receptor-gamma and lipin 1), adipokine secretion and expression of the insulin signalling mediator pAktSer473. The metabolic effects of telmisartan followed a non-monotonic response with the maximal effect observed at 5 µM in the primary human adipocyte model. Telmisartan has beneficial metabolic effects in adipocytes in vitro, but its potential to reduce antiretroviral-induced cardiometabolic disease in HIV-infected individuals needs to be evaluated in a well-designed adequately powered clinical trial.