Umeå University's logo

Aims/hypothesis: The aim of the study was to investigate ectopic fat deposition and insulin sensitivity, in a parallel single-blinded randomised controlled trial, comparing Paleolithic diet alone with the combination of Paleolithic diet and exercise in individuals with type 2 diabetes. Methods: Thirty-two individuals with type 2 diabetes with BMI 25-40 kg/m(2) and 30-70 years of age followed a Paleolithic diet ad libitum for 12 weeks. In addition, study participants were randomised by computer program to either supervised combined exercise training (PD-EX group) or standard care exercise recommendations (PD group). Staff performing examinations and assessing outcomes were blinded to group assignment. Thirteen participants were analysed in each group: hepatic and peripheral insulin sensitivity were measured using the hyperinsulinaemic-euglycaemic clamp technique combined with [6,6-H-2(2)]glucose infusion, and liver fat was assessed by proton magnetic resonance spectroscopy; both analyses were secondary endpoints. Intramyocellular lipid (IMCL) content was measured by magnetic resonance spectroscopy as a secondary analysis. All examinations were performed at Umca University Hospital, Umca, Sweden. Results: Both study groups showed a median body weight loss of 7 kg. Fat mass decreased by 5.7 kg in the PD group and by 6.5 kg in the PD-EX group. Maximum oxygen uptake increased in the PD-EX group only. Liver fat showed a consistent reduction (74% decrease) in the PD group, while the response in the PD-EX group was heterogeneous (p < 0.05 for the difference between groups). IMCL content of the soleus muscle decreased by 40% in the PD group and by 22% in the PD-EX group (p < 0.05 for the difference between groups). Both groups improved their peripheral and adipose tissue insulin sensitivity, but not their hepatic insulin sensitivity. Plasma fetuin-A decreased by 11% in the PD group (p < 0.05) and remained unchanged in the PD-EX group. Liver fat changes during the intervention were correlated with changes in fetuin-A (r(S) = 0.63, p < 0.01). Participants did not report any important adverse events caused by the intervention. Conclusions/interpretation: A Paleolithic diet reduced liver fat and IMCL content, while there was a tissue-specific heterogeneous response to added exercise training.

OBJECTIVE: Abdominal fat accumulation after menopause is associated with low-grade inflammation and increased risk of metabolic disorders. Effective long-term lifestyle treatment is therefore needed.

METHODS: Seventy healthy postmenopausal women (age 60 ± 5.6 years) with BMI 32.5 ± 5.5 were randomized to a Paleolithic-type diet (PD) or a prudent control diet (CD) for 24 months. Blood samples and fat biopsies were collected at baseline, 6 months, and 24 months to analyze inflammation-related parameters.

RESULTS: Android fat decreased significantly more in the PD group (P = 0.009) during the first 6 months with weight maintenance at 24 months in both groups. Long-term significant effects (P < 0.001) on adipose gene expression were found for toll-like receptor 4 (decreased at 24 months) and macrophage migration inhibitory factor (increased at 24 months) in both groups. Serum interleukin 6 (IL-6) and tumor necrosis factor α levels were decreased at 24 months in both groups (P < 0.001) with a significant diet-by-time interaction for serum IL-6 (P = 0.022). High-sensitivity C-reactive protein was decreased in the PD group at 24 months (P = 0.001).

CONCLUSIONS: A reduction of abdominal obesity in postmenopausal women is linked to specific changes in inflammation-related adipose gene expression.

Hepatosteatosis is associated with the development of both hepatic insulin resistance and Type 2 diabetes. Hepatic expression of Cd36, a fatty acid transporter, is enhanced in obese and diabetic murine models and human nonalcoholic fatty liver disease, and thus it correlates with hyperinsulinemia, steatosis, and insulin resistance. Here, we have explored the effect of hyperinsulinemia on hepatic Cd36 expression, development of hepatosteatosis, insulin resistance, and dysglycemia. A 3-week sucrose-enriched diet was sufficient to provoke hyperinsulinemia, hepatosteatosis, hepatic insulin resistance, and dysglycemia in CBA/J mice. The development of hepatic steatosis and insulin resistance in CBA/J mice on a sucrose-enriched diet was paralleled by increased hepatic expression of the transcription factor Ppar gamma and its target gene Cd36 whereas that of genes implicated in lipogenesis, fatty acid oxidation, and VLDL secretion was unaltered. Additionally, we demonstrate that insulin, in a Ppar gamma-dependent manner, is sufficient to directly increase Cd36 expression in perfused livers and isolated hepatocytes. Mouse strains that display low insulin levels, i.e. C57BL6/J, and/or lack hepatic Ppar gamma, i.e. C3H/HeN, do not develop hepatic steatosis, insulin resistance, or dysglycemia on a sucrose-enriched diet, suggesting that elevated insulin levels, via enhanced CD36 expression, provoke fatty liver development that in turn leads to hepatic insulin resistance and dysglycemia. Thus, our data provide evidence for a direct role for hyperinsulinemia in stimulating hepatic Cd36 expression and thus the development of hepatosteatosis, hepatic insulin resistance, and dysglycemia.

Aims: A high consumption of fructose leads not only to peripheral changes in insulin sensitivity and vascular function, but also to central changes in several brain regions. Given the role of the endogenous cannabinoid system in the control of energy intake, we undertook a pilot study to determine whether a high fructose diet produced changes in brain CB1 receptor functionality. Main methods: Male rats given access ad libitum to normal chow were given either water, glucose or fructose solutions to drink. CBI receptor functionality was measured autoradiographically as the increase in [35SJGTP)/S binding produced by the agonist CP55,940. Key findings: Seven regions were investigated: the prefrontal cortex, caudate-putamen, hippocampal CAI-CA3, dentate gyrus, amygdala, and dorsomedial and ventromedial hypothalami. Two-way robust Wilcoxon analyses for each brain region indicated that the dietary treatment did not produce significant main effects upon agonist-stimulated [35S]GThyS binding in any of the regions, in contrast to a significant main effect upon both leptin and adiponectin levels in the blood. However, a MANCOVA of the data controlling for leptin and adiponectin as co-variables identified a significant effect of glucose and fructose treatment for five weeks upon the [35S]GTPI/S response in the ventromedial hypothalamus, a region of importance for regulation of appetite. Significance: It is concluded from this pilot study that palatable solutions do not produce overt changes in brain CBI receptor functionality, although subtle changes in discrete brain regions may occur.

Aims: A high fat diet (HFD) has been found to affect neurotransmission in the prefrontal cortex, but the effects of this dietary regime upon the endocannabinoid system has not been studied in this brain region. In consequence, in the present study, we have investigated the effect of HFD for up to 20 weeks upon the endocannabinoid system in the prefrontal cortex of female rats.

Main methods: CB1 receptor functionality was measured using CP55,940-stimulated [S-35] GTP gamma S autoradiography. Fatty acid amide hydrolase and monoacylglycerol lipase activities were analysed in brain regions by assessing rates of [H-3] anandamide and JZL184-sensitive [H-3]2-oleoylglycerol hydrolysis, respectively.

Key findings: In the prefrontal cortex, a significantly greater stimulation of [S-35] GTP gamma S binding by CP55,940 was seen following 4-12, but not 16-20 weeks of HFD. No significant changes were seen for the caudate-putamen, CA1-CA3 region of the hippocampus or the dentate gyrus. The increased response for the 12 week animals was not accompanied by a significant change in the receptor density, measured with [H-3]CP55,940 autoradiography. No significant changes in the activity of the endocannabinoid hydrolytic enzymes fatty acid amide or monoacylglycerol lipase were seen in the prefrontal cortex, hippocampus, amygdala or hypothalamus following either 12 or 20 weeks of HFD.

Significance: It is concluded that HFD produces an increased CB1 receptor functionality in the prefrontal cortex of female rats. Given that the endocannabinoid system regulates neurotransmission in the prefrontal cortex, the present data would implicate this system in the disturbed prefrontal cortical activity in this region following a high fat diet.

Over the last decade, telomere length (TL) has gained attention as a potential biomarker in cancer disease. We previously reported that long blood TL was associated with a poorer outcome in patients with breast cancer and renal cell carcinoma. Based on these findings, we hypothesized that certain immunological components may have an impact on TL dynamics in cancer patients. One aim of the present study was to investigate a possible association between serum cytokines and TL of peripheral blood cells, tumors and corresponding kidney cortex, in patients with clear cell renal cell carcinoma. For this purpose, a multiplex cytokine assay was used. Correlation analysis revealed significant positive correlations between tumor TL and peripheral levels of three cytokines (IL-7, IL-8 and IL-10). In a parallel patient group with various kidney tumors, TL was investigated in whole blood and in immune cell subsets in relation to peripheral levels of regulatory T cells (Tregs). A significant positive association was found between whole blood TL and Treg levels. However, the strongest correlation was found between Tregs and TL of the T lymphocyte fraction. Thus, patients with higher Treg levels displayed longer T cell telomeres, which might reflect a suppressed immune system with fewer cell divisions and hence less telomere shortening. These results are in line with our earlier observation that long blood TL is an unfavorable prognostic factor for cancer-specific survival. In summary, we here show that immunological components are associated with TL in patients with renal cell carcinoma, providing further insight into the field of telomere biology in cancer. 

Objective:  The menopausal transition is characterized by increased body fat accumulation, including redistribution from peripheral to central fat depots. This distribution is associated with an increased risk of type 2 diabetes and cardiovascular disease which are linked to low-grade inflammation. We determined whether postmenopausal women have higher levels of inflammatory markers, compared to premenopausal women. We also wanted to determine if these markers are reduced by stable weight loss in obese women. Design and methods:  Anthropometric data, blood samples, and subcutaneous adipose tissue biopsies were collected from normal weight premenopausal and postmenopausal women and obese women before and 2 years after gastric bypass surgery. Serum protein levels and adipose tissue gene expression of inflammatory markers were investigated. Results:  IL-8 expression in adipose tissue and circulating levels were higher in postmenopausal versus premenopausal women. IL-8 expression was associated with waist circumference, independent of menopausal status. IL-6 expression and serum levels of monocyte chemoattractant protein (MCP)-1 were higher in postmenopausal versus premenopausal women. Two years after gastric bypass surgery, adipose expression of IL-8, tumor necrosis factor-α, and MCP-1 decreased significantly. Serum insulin levels were associated with inflammation-related gene expression before gastric bypass surgery, but these associations disappeared after surgery. Conclusion:  Postmenopausal women have an increased inflammatory response in the subcutaneous fat and circulation. Inflammatory markers in adipose tissue decreased significantly after surgery-induced weight loss. This effect may be beneficial for metabolic control and reduced cardiovascular risk after weight loss. © 2011 Blackwell Publishing Ltd.

Objective: 11 beta-Hydroxysteroid dehydrogenase type I (11 beta HSD1) regenerates active cortisol from inert cortisone in adipose tissue. Elevated adipose tissue 11 beta HSD1 activity is observed in obese humans and rodents, where it is linked to obesity and its metabolic consequences. Menopause is also associated with increased abdominal fat accumulation, suggesting that estrogen is also important in adipose tissue metabolism. The purpose of this current study was to establish whether estrogen signaling through estrogen receptor alpha (ER-alpha) and estrogen receptor beta (ER-beta) could influence 11 beta HSD1 in premenopausal and postmenopausal adipose tissues. Methods: Nineteen premenopausal (aged 26 +/- 5 y; body mass index, 23.6 +/- 1.6 kg/m(2)) and 23 postmenopausal (aged 63 +/- 4 y; body mass index, 23.4 +/- 1.9 kg/m(2)) healthy women were studied. Subcutaneous adipose tissue biopsies and fasting venous blood samples were taken. Body composition was measured by bioelectrical impedance analysis. Human Simpson-Golabi-Behmel syndrome adipocyte cells were treated with ER-alpha- and ER-beta-specific agonists for 24 hours. Basic anthropometric data, serum 17 beta-estradiol and progesterone concentrations, ER-alpha and ER-beta messenger RNA (mRNA) levels, and 11 beta HSD1 mRNA, protein, and activity levels were assessed. Results: ER-beta and 11 beta HSD1, but not ER-alpha, mRNAs were significantly increased in adipose tissue from postmenopausal women compared with premenopausal women. ER-beta had a significant positive correlation with the mRNA level of 11 beta HSD1 in adipose tissue from premenopausal and postmenopausal women. This association between ER-beta and 11 beta HSD1 was greatest in adipose tissue from postmenopausal women. In human Simpson-Golabi-Behmel syndrome adipocytes, diarylpropiolnitrile, a selective ER-beta agonist, increased 11 beta HSD1 mRNA, protein, and activity levels. Conclusions: We conclude that, in adipose tissue, ER-beta-mediated estrogen signaling can up-regulate 11 beta HSD1 and that this may be of particular importance in postmenopausal women.