| 1. |
- Mannerås, Louise, 1980, et al.
(författare)
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A new rat model exhibiting both ovarian and metabolic characteristics of polycystic ovary syndrome.
- 2007
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 148:8, s. 3781-91
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Tidskriftsartikel (refereegranskat)abstract
- Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, abdominal obesity, and insulin resistance. However, its etiology is unclear, and its management is often unsatisfactory or requires a diversified approach. Here, we describe a new rat PCOS model, the first to exhibit both ovarian and metabolic characteristics of the syndrome. Female rats received the nonaromatizable androgen dihydrotestosterone (DHT) or the aromatase inhibitor letrozole by continuous administration, beginning before puberty, to activate androgen receptors. Adult DHT rats had irregular cycles, polycystic ovaries characterized by cysts formed from atretic follicles, and a diminished granulosa layer. They also displayed metabolic features, including increased body weight, increased body fat, and enlarged mesenteric adipocytes, as well as elevated leptin levels and insulin resistance. All letrozole rats were anovulatory and developed polycystic ovaries with structural changes strikingly similar to those in human PCOS. Our findings suggest that the formation of a "hyperplastic" theca interna reflects the inclusion of luteinized granulosa cells in the cyst wall rather than true hyperplasia. We conclude that the letrozole model is suitable for studies of the ovarian features of human PCOS, while the DHT model is suitable for studies of both ovarian and metabolic features of the syndrome.
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| 2. |
- Alexanderson, Camilla, 1978, et al.
(författare)
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Postnatal testosterone exposure results in insulin resistance, enlarged mesenteric adipocytes, and an atherogenic lipid profile in adult female rats: comparisons with estradiol and dihydrotestosterone.
- 2007
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 148:11, s. 5369-76
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Tidskriftsartikel (refereegranskat)abstract
- Postnatal events contribute to features of the metabolic syndrome in adulthood. In this study, postnatally administered testosterone reduced insulin sensitivity and increased the mesenteric fat depot, the size of mesenteric adipocytes, serum levels of total cholesterol, low-density lipoprotein cholesterol, and triglycerides, and the atherogenic index in adult female rats. To assess the involvement of estrogen and androgen receptors in these programming effects, we compared testosterone-exposed rats to rats exposed to estradiol or dihydrotestosterone (DHT). Estradiol-treated rats had lower insulin sensitivity than testosterone-treated rats and, like those rats, had enlarged mesenteric adipocytes and increased triglyceride levels. DHT also reduced insulin sensitivity but did not mimic the other metabolic effects of testosterone. All treated rats were probably anovulatory, but only those treated with testosterone had reduced testosterone levels. This study confirms our previous finding that postnatal administration of testosterone reduces insulin sensitivity in adult female rats and shows that this effect is accompanied by unfavorable changes in mesenteric fat tissue and in serum lipid levels. The findings in the estradiol and DHT groups suggest that estrogen receptors exert stronger metabolic programming effects than androgen receptors. Thus, insults such as sex hormone exposure in early life may have long-lasting effects, thereby creating a predisposition to disturbances in insulin sensitivity, adipose tissue, and lipid profile in adulthood.
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| 3. |
- Behre, Carl Johan, 1968, et al.
(författare)
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Dissociation between adipose tissue expression and serum levels of adiponectin during and after diet-induced weight loss in obese subjects with and without the metabolic syndrome
- 2007
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Ingår i: Metabolism: Clinical and Experimental. - : Elsevier BV. - 0026-0495 .- 1532-8600. ; 56:8, s. 1022-8
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Tidskriftsartikel (refereegranskat)abstract
- The study aimed to examine if dysmetabolic subjects (MetS+) have lower adiponectin gene expression and lower circulating adiponectin levels than non-dysmetabolic obese subjects (MetS-) at baseline, if adiponectin expression and adiponectin concentration rise more in the dysmetabolic group during weight loss, and if v-SNARE Vti1a (vesicle transport soluble NSF attachment protein receptor vps10p tail interacting 1a) expression increases during the weight loss, as a mechanism for increased adiponectin secretion. Twenty-one obese MetS+ and 19 obese MetS- subjects underwent a very low-energy diet for 16 weeks followed by 2 weeks of refeeding. Abdominal subcutaneous adipose tissue biopsies and blood samples were taken before, during, and after dieting for DNA microarray, reverse transcriptase-polymerase chain reaction, and biochemical analyses. Serum adiponectin was also assessed in a sex- and age-matched healthy, nonobese reference group. Weight decreased by 26.3+/-9.8 kg in the MetS+ group and 28.2+/-8.4 kg in the MetS- group with concomitant reductions in insulin, hemoglobin A1c, and triglycerides that were more pronounced in the MetS+ group. Initially, the MetS+ subjects had lower serum adiponectin, but the differences disappeared at week 8, with a continuous increase in serum adiponectin throughout the study in both groups to a level that was higher than in the reference group. The expression of adiponectin and v-SNARE Vti1a did not differ between the groups or over time. In conclusion, obese subjects with the metabolic syndrome had lower circulating adiponectin than subjects without the syndrome. Weight loss increased serum levels of adiponectin without a parallel increase in adiponectin gene expression. The mechanisms involved in the regulation of adiponectin levels merits further investigation.
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| 4. |
- Gummesson, Anders, 1973, et al.
(författare)
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Relations of Adipose Tissue Cell Death-Inducing DFFA-like Effector A Gene Expression to Basal Metabolic Rate, Energy Restriction and Obesity: Population-based and Dietary Intervention Studies.
- 2007
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 92:12, s. 4759-65
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Tidskriftsartikel (refereegranskat)abstract
- Context: Cell death-inducing DFFA-like effector A (CIDEA) could be a potential target for the treatment of obesity via the modulation of metabolic rate, based on the findings that CIDEA inhibits the brown adipose tissue uncoupling process in rodents. Objective: To investigate the putative link between CIDEA and basal metabolic rate in humans, and to further elucidate the role of CIDEA in human obesity. Design: We have explored CIDEA gene expression in adipose tissue in two different human studies: A cross-sectional and population-based study assessing body composition and metabolic rate (Mölndal Metabolic study, n=92), and a longitudinal intervention-study of obese subjects treated with a very low calorie diet (VLCD study, n=24). Results: The CIDEA gene was predominantly expressed in adipocytes as compared to other human tissues. CIDEA gene expression in adipose tissue was inversely associated with basal metabolic rate independently of body composition, age and gender (p=0.014). VLCD induced an increase in adipose tissue CIDEA expression (p<0.0001) with a subsequent decrease in response to refeeding (p<0.0001). Reduced CIDEA gene expression was associated with a high body fat content (p<0.0001) and with high insulin levels (p<0.01). No dysregulation of CIDEA expression was observed in individuals with the metabolic syndrome when compared with BMI-matched controls. In a separate sample of VLCD-treated subjects (n=10), uncoupling protein 1 expression was reduced during diet (p=0.0026) and inversely associated with CIDEA expression (p=0.0014). Conclusion: The findings are consistent with the concept that CIDEA plays a role in adipose tissue energy expenditure.
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| 5. |
- Palming, Jenny, 1975, et al.
(författare)
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The expression of NAD(P)H:quinone oxidoreductase 1 is high in human adipose tissue, reduced by weight loss, and correlates with adiposity, insulin sensitivity, and markers of liver dysfunction.
- 2007
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 92:6, s. 2346-52
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: We have previously identified nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1 (NQO1), an enzyme involved in the protection against oxidative stress, as a gene predominantly expressed in human adipocytes. Studies in mice deficient in NQO1 activity suggest that NQO1 may also play an important role in metabolism. OBJECTIVE: The aim of this study was to explore the expression and regulation of NQO1 in human adipose tissue (AT) and isolated adipocytes. PATIENTS AND RESULTS: The high expression of NQO1 in adipocytes was verified in human adipocytes and AT by real-time PCR. DNA microarray analysis showed that NQO1 was expressed at higher levels in large compared with small adipocytes, isolated from the same fat biopsy. Furthermore, NQO1 mRNA levels were positively correlated with adipocyte size (n = 7; P < 0.002). During an 18-wk diet regime (n = 24; mean weight loss 27 kg), the NQO1 expression in human sc AT was down-regulated (P < 0.0001), and mRNA levels correlated with body mass index (P = 0.0005), sc, and total abdominal AT areas, as determined by computerized tomography (P < 0.0001, both) and metabolic parameters. NQO1 mRNA levels were also positively correlated with aspartate aminotransferase (P = 0.0028) and alanine aminotransferase (P = 0.0219), markers known to be associated with severity of hepatic steatosis. CONCLUSIONS: NQO1 is highly expressed in human AT, particularly in large adipocytes. AT NQO1 expression is reduced during diet-induced weight loss, and the expression levels positively correlate with adiposity, glucose tolerance, and markers of liver dysfunction. Together, these findings indicate a role for NQO1 in the metabolic complications of human obesity.
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| 6. |
- Sjöström, Lars, et al.
(författare)
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Effects of bariatric surgery on mortality in Swedish obese subjects.
- 2007
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Ingår i: The New England journal of medicine. - 1533-4406. ; 357:8, s. 741-52
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Obesity is associated with increased mortality. Weight loss improves cardiovascular risk factors, but no prospective interventional studies have reported whether weight loss decreases overall mortality. In fact, many observational studies suggest that weight reduction is associated with increased mortality. METHODS: The prospective, controlled Swedish Obese Subjects study involved 4047 obese subjects. Of these subjects, 2010 underwent bariatric surgery (surgery group) and 2037 received conventional treatment (matched control group). We report on overall mortality during an average of 10.9 years of follow-up. At the time of the analysis (November 1, 2005), vital status was known for all but three subjects (follow-up rate, 99.9%). RESULTS: The average weight change in control subjects was less than +/-2% during the period of up to 15 years during which weights were recorded. Maximum weight losses in the surgical subgroups were observed after 1 to 2 years: gastric bypass, 32%; vertical-banded gastroplasty, 25%; and banding, 20%. After 10 years, the weight losses from baseline were stabilized at 25%, 16%, and 14%, respectively. There were 129 deaths in the control group and 101 deaths in the surgery group. The unadjusted overall hazard ratio was 0.76 in the surgery group (P=0.04), as compared with the control group, and the hazard ratio adjusted for sex, age, and risk factors was 0.71 (P=0.01). The most common causes of death were myocardial infarction (control group, 25 subjects; surgery group, 13 subjects) and cancer (control group, 47; surgery group, 29). CONCLUSIONS: Bariatric surgery for severe obesity is associated with long-term weight loss and decreased overall mortality.
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