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Effects of altitude and recombinant human erythropoietin on iron metabolism: a randomized controlled trial.
Breenfeldt Andersen, A, Bonne, TC, Bejder, J, Jung, G, Ganz, T, Nemeth, E, Olsen, NV, Huertas, JR, Nordsborg, NB
American journal of physiology. Regulatory, integrative and comparative physiology. 2021;(2):R152-R161
Abstract
Current markers of iron deficiency (ID), such as ferritin and hemoglobin, have shortcomings, and hepcidin and erythroferrone (ERFE) could be of clinical relevance in relation to early assessment of ID. Here, we evaluate whether exposure to altitude-induced hypoxia (2,320 m) alone, or in combination with recombinant human erythropoietin (rHuEPO) treatment, affects hepcidin and ERFE levels before alterations in routine ID biomarkers and stress erythropoiesis manifest. Two interventions were completed, each comprising a 4-wk baseline, a 4-wk intervention at either sea level or altitude, and a 4-wk follow-up. Participants (n = 39) were randomly assigned to 20 IU·kg body wt-1 rHuEPO or placebo injections every second day for 3 wk during the two intervention periods. Venous blood was collected weekly. Altitude increased ERFE (P ≤ 0.001) with no changes in hepcidin or routine iron biomarkers, making ERFE of clinical relevance as an early marker of moderate hypoxia. rHuEPO treatment at sea level induced a similar pattern of changes in ERFE (P < 0.05) and hepcidin levels (P < 0.05), demonstrating the impact of accelerated erythropoiesis and not of other hypoxia-induced mechanisms. Compared with altitude alone, concurrent rHuEPO treatment and altitude exposure induced additive changes in hepcidin (P < 0.05) and ERFE (P ≤ 0.001) parallel with increases in hematocrit (P < 0.001), demonstrating a relevant range of both hepcidin and ERFE. A poor but significant correlation between hepcidin and ERFE was found (R2 = 0.13, P < 0.001). The findings demonstrate that hepcidin and ERFE are more rapid biomarkers of changes in iron demands than routine iron markers. Finally, ERFE and hepcidin may be sensitive markers in an antidoping context.
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Appetitive hormones, but not isoflavone tablets, influence overall and central adiposity in healthy postmenopausal women.
Matvienko, OA, Alekel, DL, Genschel, U, Ritland, L, Van Loan, MD, Koehler, KJ
Menopause (New York, N.Y.). 2010;(3):594-601
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Abstract
OBJECTIVE One of the multiple health benefits of soy protein or its isoflavones may be their purported favorable effect on body composition. We examined the effect of isoflavones extracted from soy protein on overall and regional body composition, taking into account appetitive hormones as potential mediators, as well as the direct effect on appetitive hormones. METHODS This randomized, double-blind, placebo-controlled multicenter trial included 229 healthy postmenopausal women (age, 45.8-65 y; body mass index, 24.9 +/- 3.0 kg/m) who consumed placebo or soy isoflavone (80 or 120 mg/d) tablets for 12 months. We used intent-to-treat analysis to examine changes in body composition (whole-body lean mass, whole-body fat mass, androidal fat mass, and androidal-to-gynoidal fat mass ratio) and appetitive hormones (insulin, leptin, ghrelin, and adiponectin) in response to treatment. RESULTS Repeated-measures analysis of variance indicated that soy isoflavone treatment did not exert a significant effect on body composition measures (P value from 0.36 to 0.79) or appetitive hormone concentrations; the inclusion of covariates in statistical models did not alter these results. Independently of treatment, leptin and ghrelin related inversely to each body composition measure (P values from 0.044 to < or = 0.0001). Adiponectin related inversely to all fat measures (P values from 0.0004 to <0.0001). Time since last menstrual period related directly to all fat measures (P values from 0.06 to 0.0055). Dietary fat contributed to whole-body (P = 0.028) and androidal (P = 0.017) fat mass. CONCLUSIONS Our findings do not support a favorable effect of soy isoflavone tablets on body composition in healthy postmenopausal women.
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Plasma ghrelin concentrations are positively associated with carotid artery atherosclerosis in males.
Pöykkö, SM, Kellokoski, E, Ukkola, O, Kauma, H, Päivänsalo, M, Kesäniemi, YA, Hörkkö, S
Journal of internal medicine. 2006;(1):43-52
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Abstract
BACKGROUND Ghrelin, a peptide hormone from stomach, stimulates food intake and decreases fat utilization. Ghrelin binds to growth hormone secretagogue receptor (GHSR). GHSR density has been shown to be upregulated in atherosclerotic lesions, but the relationship between ghrelin concentration and atherosclerosis has not yet been studied. We, therefore, characterized the association between ghrelin concentration and carotid artery intima-media thickness (IMT) in a population-based cohort of 1024 middle-aged (40-60 years) men and women. METHODS Intima-media thickness and the number of atherosclerotic plaques were determined ultrasonographically. Fasting plasma ghrelin concentrations were analysed using RIA-kit (PhoenixPeptide). RESULTS There was a positive association between mean IMT and ghrelin concentration in the analysis of males before and after adjustments for the traditional risk factors of atherosclerosis [age, systolic blood pressure, LDL cholesterol, body mass index (BMI), and smoking (ancova, P = 0.004 and P = 0.007, respectively)]. However, no such association was found in females (P = 0.985 and P = 0.915). There was no correlation between ghrelin and CRP concentrations or ghrelin and smoking. CONCLUSION Ghrelin concentrations and carotid artery atherosclerosis are positively associated in males even after adjustment for the commonly recognized risk factors of atherosclerosis. Experimental and prospective studies are warranted to elucidate the role of ghrelin in atherosclerosis.
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Soy isoflavones increase preprandial peptide YY (PYY), but have no effect on ghrelin and body weight in healthy postmenopausal women.
Weickert, MO, Reimann, M, Otto, B, Hall, WL, Vafeiadou, K, Hallund, J, Ferrari, M, Talbot, D, Branca, F, Bügel, S, et al
Journal of negative results in biomedicine. 2006;:11
Abstract
BACKGROUND Soy isoflavones show structural and functional similarities to estradiol. Available data indicate that estradiol and estradiol-like components may interact with gut "satiety hormones" such as peptide YY (PYY) and ghrelin, and thus influence body weight. In a randomized, double-blind, placebo-controlled, cross-over trial with 34 healthy postmenopausal women (59 +/- 6 years, BMI: 24.7 +/- 2.8 kg/m2), isoflavone-enriched cereal bars (50 mg isoflavones/day; genistein to daidzein ratio 2:1) or non-isoflavone-enriched control bars were consumed for 8 weeks (wash-out period: 8-weeks). Seventeen of the subjects were classified as equol producers. Plasma concentrations of ghrelin and PYY, as well as energy intake and body weight were measured at baseline and after four and eight weeks of each intervention arm. RESULTS Body weight increased in both treatment periods (isoflavone: 0.40 +/- 0.94 kg, P < 0.001; placebo: 0.66 +/- 0.87 kg, P = 0.018), with no significant difference between treatments. No significant differences in energy intake were observed (P = 0.634). PYY significantly increased during isoflavone treatment (51 +/- 2 pmol/L vs. 55 +/- 2 pmol/L), but not during placebo (52 +/- 3 pmol/L vs. 50 +/- 2 pmol/L), (P = 0.010 for treatment differences, independent of equol production). Baseline plasma ghrelin was significantly lower in equol producers (110 +/- 16 pmol/L) than in equol non-producers (162 +/- 17 pmol/L; P = 0.025). CONCLUSION Soy isoflavone supplementation for eight weeks did not significantly reduce energy intake or body weight, even though plasma PYY increased during isoflavone treatment. Ghrelin remained unaffected by isoflavone treatment. A larger and more rigorous appetite experiment might detect smaller differences in energy intake after isoflavone consumption. However, the results of the present study do not indicate that increased PYY has a major role in the regulation of body weight, at least in healthy postmenopausal women.
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Association between ghrelin gene variations and blood pressure in subjects with impaired glucose tolerance.
Mager, U, Kolehmainen, M, Lindström, J, Eriksson, JG, Valle, TT, Hämäläinen, H, Ilanne-Parikka, P, Keinänen-Kiukaanniemi, S, Tuomilehto, JO, Pulkkinen, L, et al
American journal of hypertension. 2006;(9):920-6
Abstract
BACKGROUND Ghrelin is a gut-brain hormone, which stimulates food intake and controls energy balance. Recently, it has been shown that ghrelin may also play a role in the regulation of blood pressure (BP) by acting at the sympathetic nervous system. In the present study we genotyped six variants of the ghrelin gene and its promoter, and tested whether these single nucleotide polymorphisms (SNPs) were associated with BP levels in participants of the Finnish Diabetes Prevention Study. METHODS The Finnish Diabetes Prevention Study was a longitudinal study where 522 subjects with impaired glucose tolerance were randomized into either an intervention or control group. DNA was available from 507 subjects (mean body mass index [BMI] 31.2+/-4.5 kg/m2, age 55+/-7 years). All six SNPs were screened by the restriction fragment length polymorphism method. RESULTS Subjects with the most common genotype combination of the following four SNPs, -604G/A, -501A/C, Leu72Met, and Gln90Leu, had the lowest systolic (131+/-11 v 137+/-13 mm Hg, P=.003) and diastolic BP levels (79+/-7 v 83+/-7 mm Hg, P=.004) at the baseline of the study and during 3 years of follow-up compared to all other genotypes. Adjustments for age, gender, antihypertensive medication, BMI, waist circumference, and alcohol intake did not change this association. CONCLUSIONS Several ghrelin gene variations were associated with BP levels in subjects with impaired glucose tolerance.
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Human plasma ghrelin levels increase during a one-year exercise program.
Foster-Schubert, KE, McTiernan, A, Frayo, RS, Schwartz, RS, Rajan, KB, Yasui, Y, Tworoger, SS, Cummings, DE
The Journal of clinical endocrinology and metabolism. 2005;(2):820-5
Abstract
Weight loss resulting from decreased caloric intake raises levels of the orexigenic hormone, ghrelin. Because ingested nutrients suppress ghrelin, increased ghrelin levels in hypophagic weight loss may result from decreased inhibitory input by ingested food, rather than from lost weight. We assessed whether ghrelin levels increase in response to exercise-induced weight loss without decreased caloric intake. We randomized 173 sedentary, overweight, postmenopausal women to an aerobic exercise intervention or stretching control group. At baseline, 3 months, and 12 months, we measured body weight and composition, food intake, cardiopulmonary fitness (maximal oxygen consumption), leptin, insulin, and ghrelin. Complete data were available for 168 women (97%) at 12 months. Exercisers lost 1.4 +/- 0.4 kg (P < 0.05 compared with baseline; P = 0.01 compared with stretchers) and manifested a significant, progressive increase in ghrelin levels, whereas neither measure changed among stretchers. Ghrelin increased 18% in exercisers who lost more than 3 kg (P < 0.001). There was no change in caloric intake in either group and no effect on ghrelin of exercise per se independent of its impact on body weight. In summary, ghrelin levels increase with weight loss achieved without reduced food intake, consistent with a role for ghrelin in the adaptive response constraining weight loss and, thus, in long-term body weight regulation.
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Progress in implantable gastric stimulation: summary of results of the European multi-center study.
De Luca, M, Segato, G, Busetto, L, Favretti, F, Aigner, F, Weiss, H, de Gheldere, C, Gaggiotti, G, Himpens, J, Limao, J, et al
Obesity surgery. 2004;:S33-9
Abstract
BACKGROUND The Implantable Gastric Stimulator (IGS(R)), a pacemaker-like device, has been found to be safe and effective to induce and maintain weight loss. The LOSS (Laparoscopic Obesity Stimulation Survey) is a prospective non-randomized trial which enrolled 69 patients involving 11 investigator centers in 5 European Countries. In 19 patients, ghrelin was analyzed. METHODS Between January 2002 and December 2003, 69 patients (F/M 49/20), mean age 41 years (18-65) underwent IGS implantation. Mean BMI was 41 (35-57), mean weight 115.0 kg (65-160) and mean excess weight (EW) 52 kg (13-89). The IGS was actived 30 days after implantation. In a subset of 19 patients studied further, 0, 6, and 12 months appetite and satiety score were evaluated and 0 and 6 months ghrelin profile was analyzed. RESULTS The mean +/- standard error %EWL was: 8.6+/-1.8 at 1 month, 15.8+/-2.3 at 3 months, 17.8+/-2.6 at 6 months, 21.0+/-3.5 at 10 months, and 21.0+/-5.0 at 15 months. There were no intraoperative surgical or long-term complications. 7 intra-operative gastric penetrations occurred, observed by gastroscopy, without sequelae. 1 patient required a reoperation to remove a retained lead needle. In the subset of 19 patients, appetite was reduced and post-prandial and inter-prandial satiety was increased after IGS implantation. In the 19 patients, despite weight reduction, ghrelin did not increase. CONCLUSION IGS can be implanted laparoscopically with minimal perioperative complications. Appetite is reduced and satiety is increased after the implantation. Ghrelin levels could be one of the mechanisms explaining weight loss and weight maintenance in IGS patients. If weight loss is maintained, IGS could be considered a good option for selected patients.