RESUMO
AIMS/HYPOTHESIS: Elevated levels of lipoprotein(a) [Lp(a)] are an independent risk factor for cardiovascular disease (CVD), particularly in individuals with type 2 diabetes. Although weight loss improves conventional risk factors for CVD in type 2 diabetes, the effects on Lp(a) are unknown and may influence the long-term outcome of CVD after diet-induced weight loss. The aim of this clinical study was to determine the effect of diet-induced weight loss on Lp(a) levels in obese individuals with type 2 diabetes. METHODS: Plasma Lp(a) levels were determined by immunoturbidimetry in plasma obtained before and after 3-4 months of an energy-restricted diet in four independent study cohorts. The primary cohort consisted of 131 predominantly obese patients with type 2 diabetes (cohort 1), all participants of the Prevention Of Weight Regain in diabetes type 2 (POWER) trial. The secondary cohorts consisted of 30 obese patients with type 2 diabetes (cohort 2), 37 obese individuals without type 2 diabetes (cohort 3) and 26 obese individuals without type 2 diabetes who underwent bariatric surgery (cohort 4). RESULTS: In the primary cohort, the energy-restricted diet resulted in a weight loss of 9.9% (95% CI 8.9, 10.8) and improved conventional CVD risk factors such as LDL-cholesterol levels. Lp(a) levels increased by 14.8 nmol/l (95% CI 10.2, 20.6). In univariate analysis, the change in Lp(a) correlated with baseline Lp(a) levels (r = 0.38, p < 0.001) and change in LDL-cholesterol (r = 0.19, p = 0.033). In cohorts 2 and 3, the weight loss of 8.5% (95% CI 6.5, 10.6) and 6.5% (95% CI 5.7, 7.2) was accompanied by a median increase in Lp(a) of 13.5 nmol/l (95% CI 2.3, 30.0) and 11.9 nmol/l (95% CI 5.7, 19.0), respectively (all p < 0.05). When cohorts 1-3 were combined, the diet-induced increase in Lp(a) correlated with weight loss (r = 0.178, p = 0.012). In cohort 4, no significant change in Lp(a) was found (-7.0 nmol/l; 95% CI -18.8, 5.3) despite considerable weight loss (14.0%; 95% CI 12.2, 15.7). CONCLUSIONS/INTERPRETATION: Diet-induced weight loss was accompanied by an increase in Lp(a) levels in obese individuals with and without type 2 diabetes while conventional CVD risk factors for CVD improved. This increase in Lp(a) levels may potentially antagonise the beneficial cardiometabolic effects of diet-induced weight reduction.
Assuntos
Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/dietoterapia , Lipoproteína(a)/sangue , Obesidade/sangue , Obesidade/dietoterapia , Redução de Peso/fisiologia , Adulto , Idoso , Cirurgia Bariátrica , Diabetes Mellitus Tipo 2/cirurgia , Dieta Redutora , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/cirurgia , Estudos ProspectivosRESUMO
OBJECTIVE: Obesity and type 2 diabetes mellitus (T2DM) have been associated with increased levels of circulating branched-chain amino acids (BCAAs) that may be involved in the pathogenesis of insulin resistance. However, weight loss has not been consistently associated with the reduction of BCAA levels. RESEARCH DESIGN AND METHODS: We included 30 obese normal glucose-tolerant (NGT) subjects, 32 obese subjects with T2DM, and 12 lean female subjects. Obese subjects underwent either a restrictive procedure (gastric banding [GB], a very low-calorie diet [VLCD]), or a restrictive/bypass procedure (Roux-en-Y gastric bypass [RYGB] surgery). Fasting blood samples were taken for the determination of amine group containing metabolites 4 weeks before, as well as 3 weeks and 3 months after the intervention. RESULTS: BCAA levels were higher in T2DM subjects, but not in NGT subjects, compared with lean subjects. Principal component (PC) analysis revealed a concise PC consisting of all BCAAs, which showed a correlation with measures of insulin sensitivity and glucose tolerance. Only after the RYGB procedure, and at both 3 weeks and 3 months, were circulating BCAA levels reduced. CONCLUSIONS: Our data confirm an association between deregulation of BCAA metabolism in plasma and insulin resistance and glucose intolerance. Three weeks after undergoing RYGB surgery, a significant decrease in BCAAs in both NGT as well as T2DM subjects was observed. After 3 months, despite inducing significant weight loss, neither GB nor VLCD induced a reduction in BCAA levels. Our results indicate that the bypass procedure of RYGB surgery, independent of weight loss or the presence of T2DM, reduces BCAA levels in obese subjects.
Assuntos
Aminoácidos de Cadeia Ramificada/sangue , Restrição Calórica , Diabetes Mellitus Tipo 2/complicações , Derivação Gástrica , Obesidade/cirurgia , Redução de Peso/fisiologia , Adulto , Regulação para Baixo , Feminino , Intolerância à Glucose/sangue , Intolerância à Glucose/complicações , Intolerância à Glucose/dietoterapia , Intolerância à Glucose/cirurgia , Humanos , Resistência à Insulina , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/dietoterapiaRESUMO
AIMS/HYPOTHESIS: Not all obese individuals develop type 2 diabetes. Why some obese individuals retain normal glucose tolerance (NGT) is not well understood. We hypothesise that the biochemical mechanisms that underlie the function of adipose tissue can help explain the difference between obese individuals with NGT and those with type 2 diabetes. METHODS: RNA sequencing was used to analyse the transcriptome of samples extracted from visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) of obese women with NGT or type 2 diabetes who were undergoing bariatric surgery. The gene expression data was analysed by bioinformatic visualisation and statistical analyses techniques. RESULTS: A network-based approach to distinguish obese individuals with NGT from obese individuals with type 2 diabetes identified acetyl-CoA metabolic network downregulation as an important feature in the pathophysiology of type 2 diabetes in obese individuals. In general, genes within two reaction steps of acetyl-CoA were found to be downregulated in the VAT and SAT of individuals with type 2 diabetes. Upon weight loss and amelioration of metabolic abnormalities three months following bariatric surgery, the expression level of these genes recovered to levels seen in individuals with NGT. We report four novel genes associated with type 2 diabetes and recovery upon weight loss: ACAT1 (encoding acetyl-CoA acetyltransferase 1), ACACA (encoding acetyl-CoA carboxylase α), ALDH6A1 (encoding aldehyde dehydrogenase 6 family, member A1) and MTHFD1 (encoding methylenetetrahydrofolate dehydrogenase). CONCLUSIONS/INTERPRETATION: Downregulation of the acetyl-CoA network in VAT and SAT is an important feature in the pathophysiology of type 2 diabetes in obese individuals. ACAT1, ACACA, ALDH6A1 and MTHFD1 represent novel biomarkers in adipose tissue associated with type 2 diabetes in obese individuals.
Assuntos
Acetilcoenzima A/metabolismo , Tecido Adiposo/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Obesidade/enzimologia , Acetil-CoA C-Acetiltransferase/genética , Acetil-CoA Carboxilase/genética , Adipócitos/metabolismo , Adulto , Feminino , Humanos , Gordura Intra-Abdominal/metabolismo , Masculino , Metilenotetra-Hidrofolato Desidrogenase (NADP)/genética , Pessoa de Meia-Idade , Antígenos de Histocompatibilidade Menor , Obesidade/metabolismo , Análise de Sequência de RNA , Redução de Peso/fisiologiaRESUMO
OBJECTIVE: To study the effect of different weight loss strategies on levels of the metabolic regulator FGF21 in morbidly obese females with normal glucose tolerance (NGT) or type 2 diabetes mellitus (T2DM). DESIGN: Observational intervention trial. PATIENTS AND MEASUREMENTS: Weight reduction was achieved by Gastric Banding (GB, n = 11) or Roux-en-Y Gastric Bypass (RYGB, n = 16) in subjects with NGT, and by RYGB (n = 15) or a very-low-calorie diet (VLCD, n = 12) in type 2 diabetics. Fasted and/or postprandial levels of FGF21, FGF19 (an FGF21-related postprandial hormone) and bile salts (implicated in regulation of FGF21 and FGF19 expression) were measured before, and 3 and 12 weeks after intervention. RESULTS: Fasted FGF21 levels were elevated in T2DM subjects. Calorie restriction by either GB or VLCD lowered bile salt and FGF21 levels. In contrast, RYGB surgery was associated with elevated bile salt and FGF21 levels. CONCLUSIONS: Calorie restriction and RYGB have opposite effects on serum bile salt and FGF21 levels. Calorie restriction results in FGF21 approaching nonobese control levels, suggesting that this intervention is effective in reducing the "nutritional crisis" that appears to underly FGF21 elevation in obesity. FGF21 elevation after RYGB may contribute to the beneficial effect of this procedure.
Assuntos
Restrição Calórica/métodos , Diabetes Mellitus Tipo 2/sangue , Fatores de Crescimento de Fibroblastos/sangue , Derivação Gástrica/métodos , Obesidade Mórbida/terapia , Cirurgia Bariátrica/métodos , Diabetes Mellitus Tipo 2/complicações , Feminino , Humanos , Pessoa de Meia-Idade , Obesidade Mórbida/sangue , Obesidade Mórbida/complicaçõesRESUMO
OBJECTIVE: Cardiac ectopic fat depositions are thought to play a role in the pathogenesis of cardiovascular disease (CVD), the main cause of death in patients with type 2 diabetes. Diet-induced weight loss results in a decrease in cardiac ectopic fat stores, however if this is the same for surgically induced weight loss is less clear. Therefore, we assessed myocardial triglyceride (TG) content, pericardial fat and cardiac function in obese patients with insulin-dependent type 2 diabetes before and 16 weeks after Roux-en-Y gastric bypass (RYGB) surgery. PATIENTS: Ten obese patients with insulin-dependent type 2 diabetes [40% male, age 53·7 ± 8·9 years (mean ± SD)] scheduled to undergo RYGB surgery were included. MEASUREMENTS: Ectopic fat accumulation and cardiovascular function were assessed with magnetic resonance (MR) imaging and myocardial TG content with MR spectroscopy before and 16 weeks after RYGB surgery. RESULTS: Body mass index decreased from 41·3 ± 4·3 at baseline to 34·1 ± 2·8 kg/m(2) (P < 0·001) after 16 weeks. Glycemic control improved as well [HbA1c: 7·8 ± 1·1 to 6·8 ± 1·3% (62 ± 12 to 51 ± 14 mm) (P < 0·05)]. We did not observe an effect of the RYGB surgery on myocardial TG content, cardiac function or pulse wave velocity. There was a greater relative decrease in visceral (-35·5 ± 9·6%) as compared to subcutaneous fat volume (-25·0 ± 6·3%) and in paracardial (-17·3 ±17·2%) as compared to epicardial fat volume (-6·4 ± 6·0%). CONCLUSIONS: This study shows that surgical-induced weight loss leads to a larger decrease in paracardial than epicardial fat. Myocardial TG and cardiovascular function did not change.
Assuntos
Tecido Adiposo , Cirurgia Bariátrica , Fenômenos Fisiológicos Cardiovasculares , Diabetes Mellitus Tipo 2/cirurgia , Obesidade Mórbida/cirurgia , Pericárdio/metabolismo , Adolescente , Adulto , Coristoma , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/complicações , Obesidade Mórbida/fisiopatologia , Pericárdio/patologia , Análise de Onda de Pulso , Adulto JovemRESUMO
INTRODUCTION: Obesity is strongly related to type-2 diabetes (T2DM), but there is a subset of obese individuals that remains relatively insulin sensitive and metabolically healthy. This study determined to what extent differences in metabolic health in obese women are associated with differences in adipose tissue and/or systemic inflammation. METHODS: The subject group consisted of age comparable lean (n=12) and obese women either with T2DM (n=28) or normal glucose tolerance (NGT; n=26). Number of crown like structures (CLS) and adipocyte size were measured in subcutaneous and visceral adipose tissue of the obese women. Circulating cytokine and free fatty acid (FFA) levels, as well as number and activation status of peripheral leukocytes were determined. RESULTS: Obese T2DM subjects showed higher circulating levels of IL-6, FFA and glycerol as compared to obese NGT subjects. Obese T2DM subjects had higher absolute numbers of peripheral leukocytes which were mainly due to an increase of T helper cells. Activation status of circulating cytotoxic T (CD8+CD25+) and B (CD19+CD38+) cells was significantly increased in obese NGT subjects as compared to lean but was not different between the two obese groups. Subcutaneous adipose tissue of obese T2DM subjects contained more CLS than adipose tissue of obese NGT subjects. CONCLUSION: Obese T2DM subjects show higher FFA levels and adipose tissue macrophage infiltration in addition to higher levels of circulating IL-6 and numbers of CD4+ T cells than obese NGT subjects. Hence, obese T2DM subjects show a higher extent of inflammation at both the systemic and adipose tissue level.
Assuntos
Tecido Adiposo/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Teste de Tolerância a Glucose , Obesidade/fisiopatologia , Síndrome de Resposta Inflamatória Sistêmica/fisiopatologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Ácidos Graxos não Esterificados/sangue , Feminino , Citometria de Fluxo , Glicerol/sangue , Humanos , Hipoglicemiantes/uso terapêutico , Interleucina-6/sangue , Contagem de Linfócitos , Pessoa de Meia-Idade , Obesidade/sangue , Obesidade/complicações , Síndrome de Resposta Inflamatória Sistêmica/sangue , Síndrome de Resposta Inflamatória Sistêmica/complicações , Subpopulações de Linfócitos TRESUMO
OBJECTIVE: Roux-en-Y gastric bypass (RYGB) and restrictive weight loss interventions, such as gastric banding (GB) and very-low-calorie diets (VLCD) directly impact glucose metabolism, possibly by calorie restriction and/or altered secretion of gut hormones. We aimed to establish the direct endocrine and metabolic effects of RYGB compared to restrictive interventions in obese glucose-tolerant (NGT) subjects and subjects with type 2 diabetes (T2DM). DESIGN: Controlled, nonrandomized observational trial. PATIENTS AND MEASUREMENTS: Four groups of obese females received a mixed meal at baseline and 3 weeks after intervention; NGT-GB (n = 11), NGT-RYGB (n = 16), T2DM-RYGB (n = 15) and T2DM-VLCD (n = 12). Normal weight controls (n = 12) were studied once. RESULTS: At baseline, all obese subjects were hyperinsulinemic. T2DM was associated with hyperglycaemia and decreased GLP-1 levels. RYGB and VLCD reduced glucose levels to a similar extent in T2DM, insulin levels decreased only after VLCD. Comparison of restrictive intervention vs RYGB showed a more pronounced decrease in glucose and insulin AUC after restriction. In NGT and T2DM subjects, RYGB increased GLP-1 and PYY levels and decreased ghrelin levels, whereas VLCD and GB only increased GIP levels. CONCLUSIONS: These data indicate that deterioration of glucose metabolism in T2DM is associated with a decline of GLP-1 levels. Calorie restriction facilitates glucose metabolism and blunts hyperinsulinemia in obese (diabetic) humans. Additional duodenal exclusion through RYGB induces gut hormone release and hyperinsulinemia but does not improve postprandial glucose levels any further. Our data thus strongly suggest that calorie restriction underlies the short-term metabolic benefits of RYGB in obese T2DM patients.
Assuntos
Restrição Calórica , Diabetes Mellitus Tipo 2/sangue , Derivação Gástrica/métodos , Obesidade/sangue , Obesidade/cirurgia , Adiposidade , Área Sob a Curva , Glicemia/análise , Complicações do Diabetes/sangue , Feminino , Grelina/metabolismo , Glucose/metabolismo , Hormônios/metabolismo , Humanos , Hiperglicemia/sangue , Insulina/sangue , Resistência à Insulina , Mucosa Intestinal/metabolismo , Pessoa de Meia-Idade , Obesidade/complicações , Redução de PesoRESUMO
OBJECTIVE: Obesity and type 2 diabetes mellitus (T2DM) are reported to be associated with relative overactivity of the sympathetic nervous system (SNS), which is reversible by weight loss. However, direct effects of weight loss by calorie restriction vs Roux-en-Y gastric bypass (RYGB) on SNS overactivity were not studied in parallel. This study compared the effects of RYGB vs restrictive weight loss in obese patients with normal glucose tolerance (NGT) and with T2DM on SNS function as measured by heart rate variability (HRV). DESIGN AND METHODS: Lean (n=12), obese NGT (n=27) and T2DM (n=27) subjects were included in this study. Weight reduction in NGT subjects was achieved by gastric banding (GB) or RYGB and in T2DM subjects by RYGB or high-protein very-low-calorie diet (VLCD). HRV analysis was performed and blood samples were taken at baseline, 3 weeks and 3 months after intervention. RESULTS: At baseline, T2DM subjects showed SNS overactivity and NGT subjects showed similar, but non-significant, findings when compared with lean controls. Weight loss after 3 weeks was comparable in all treatment groups, whereas after 3 months, weight loss was most in VLCD and RYGB subjects. RYGB and VLCD treatment reduced SNS activity within 3 weeks in T2DM patients. After 3 months, restoration to normal autonomic nervous system activity was evident for all groups, except for the NGT-GB group. CONCLUSION: We can conclude that SNS overactivity is more pronounced in obese T2DM subjects when compared with NGT subjects. Reduction of SNS overactivity coincides with weight loss with the time-course of reduction dependent on the type of intervention. Surgery or caloric restriction may transiently induce SNS overactivity but do not prevent a direct restoration of sympathovagal balance.
Assuntos
Doenças do Sistema Nervoso Autônomo , Diabetes Mellitus Tipo 2/complicações , Dieta Redutora , Derivação Gástrica , Obesidade/dietoterapia , Adulto , Doenças do Sistema Nervoso Autônomo/dietoterapia , Doenças do Sistema Nervoso Autônomo/etiologia , Doenças do Sistema Nervoso Autônomo/cirurgia , Restrição Calórica , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Teste de Tolerância a Glucose , Humanos , Hipoglicemiantes/uso terapêutico , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/cirurgia , Sistema Nervoso Simpático/fisiopatologia , Resultado do Tratamento , Nervo Vago/fisiopatologia , Redução de PesoRESUMO
OBJECTIVE: We sought evidence of association of candidate single nucleotide polymorphisms (SNP) within the growth hormone-insulin-like growth factor 1 (IGF1) axis, largely selected on the basis of functional data available at the time of our study, with adult bone mass. METHODS: Four hundred ninety-eight men and 468 women aged 59-71 years were recruited. A lifestyle questionnaire was administered, and bone mineral content (BMC) and bone mineral density (BMD) were measured at the lumbar spine and femoral neck. Two hundred fifty-four men and 271 women had repeat bone densitometry 4 years later. DNA was obtained from whole blood samples using standard extraction techniques. Single nucleotide variants in the growth hormone releasing hormone gene (GHRH, G/A 223 Phe75Leu, rs4988492), growth hormone releasing hormone receptor gene (GHRHR, G/A 217, Ala57Thr, rs4988496), the growth hormone secretagogue receptor gene (GHSR, T/C, Gly57Gly, rs495225), and the growth hormone receptor gene (GHR, T/G, noncoding, rs2940944) were analyzed. RESULTS: In both sexes, allelic variation in the gene encoding GHRH was associated with BMC and BMD at the proximal femur and lumbar spine, with results generally stronger in women. In women, the mean BMC lumbar spine within the GHRH 11 genotype was 56.9 g, while that of the GHRH 12 genotype was 68.4 g [p < 0.001, fully adjusted for age, body mass index, cigarette and alcohol consumption, dietary calcium intake, physical activity, years since menopause, and hormone replacement therapy (HRT) use]; corresponding figures for BMD lumbar spine (GHRH 11 genotype) were 0.96 g/cm(2) versus 1.10 g/cm(2) (p < 0.001 fully adjusted). CONCLUSION: We have demonstrated a relationship between allelic variation in the gene encoding GHRH and bone density; we welcome attempts at replication in other populations.
Assuntos
Densidade Óssea/genética , Densidade Óssea/fisiologia , Hormônio do Crescimento/genética , Hormônio do Crescimento/fisiologia , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/fisiologia , Polimorfismo de Nucleotídeo Único/genética , Idoso , Estudos de Coortes , Feminino , Seguimentos , Genótipo , Hormônio Liberador de Hormônio do Crescimento/genética , Inquéritos Epidemiológicos , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/epidemiologia , Osteoporose/genética , Osteoporose/fisiopatologia , Receptores de Grelina/genética , Receptores de Neuropeptídeos/genética , Receptores de Hormônios Reguladores de Hormônio Hipofisário/genética , Fatores de Risco , Reino UnidoRESUMO
OBJECTIVE: We sought evidence of interaction between single-nucleotide polymorphisms (SNP) in the calcium-sensing receptor (CASR) gene and early life in determination of bone mineral density (BMD) among individuals from the Hertfordshire Cohort Study. METHODS: Four hundred ninety-eight men and 468 women aged 59-71 years were recruited. A lifestyle questionnaire was administered and BMD at lumbar spine and femoral neck was measured. DNA was obtained from whole blood samples using standard extraction techniques. Five SNP of the CASR gene termed CASRV1 (rs1801725, G-->T, S986A), CASRV2 (rs7614486, T-->G, untranslated), CASRV3 (rs4300957, untranslated), CASRV4 (rs3804592 G-->A, intron), and CASRV5 (rs1393189, T-->C, intron) were analyzed. RESULTS: Among women the 11 genotype of the CASRV3 SNP was associated with higher lumbar spine BMD within the lowest birthweight tertile, while the opposite pattern was observed among individuals in the highest birthweight tertile (test for interaction on 1 df, p = 0.005, adjusted for age, body mass index, physical activity, dietary calcium intake, cigarette and alcohol consumption, social class, menopausal status, and hormone replacement therapy use). Similar relationships were seen at the total femur (p = 0.042, fully adjusted) with birthweight and at the total femur according to weight at 1 year tertile among women (p < 0.001, fully adjusted). One haplotype was associated with lumbar spine BMD in women (p = 0.008, fully adjusted); these findings were replicated in a second cohort. CONCLUSION: We have found evidence of an interaction between a SNP of the CASR gene and birthweight in determination of bone mass in a UK female population.