Alterations in fatty acid metabolism in response to obesity surgery combined with dietary counseling.

BACKGROUND: The effects of obesity surgery on serum and adipose tissue fatty acid (FA) profile and FA metabolism may modify the risk of obesity-related diseases. METHODS: We measured serum (n=122) and adipose tissue (n=24) FA composition and adipose tissue mRNA expression of genes regulating FA metabolism (n=100) in participants of the Kuopio Obesity Surgery Study (KOBS, age 47.2±8.7 years, BMI 44.6±6.0, 40 men, 82 women) before and one year after obesity surgery. As part of the surgery protocol, all the subjects were instructed to add sources of unsaturated fatty acids, such as rapeseed oil and fatty fish, into their diet. The results were compared with changes in serum FA composition in 122 subjects from the Finnish Diabetes Prevention study (DPS) (age 54.3±7.1 years, BMI 32.2±4.6, 28 men, 94 women). RESULTS: The proportion of saturated FAs decreased and the proportion of n-3 and n-6 FAs increased in serum triglycerides after obesity surgery (all P<0.002). Weight loss predicted changes in quantitative amounts of saturated FAs, monounsaturated FAs, n-3 and n-6 FAs in triglycerides (P<0.002 for all). Moreover, the changes in adipose tissue FAs reflected the changes in serum FAs, and some of the changes were associated with mRNA expression of elongases and desaturases in adipose tissue (all P<0.05). In line with this the estimated activity of elongase (18:1 n-7/16:1 n-7) increased significantly after obesity surgery in all lipid fractions (all P<4 × 10-7) and the increase in the estimated activity of D5D in triglycerides was associated with higher weight loss (r=0.415, P<2 × 10-6). Changes in serum FA profile were similar after obesity surgery and lifestyle intervention, except for the change in the absolute amounts of n-3 FAs between the two studies (P=0.044). CONCLUSIONS: Beneficial changes in serum and adipose tissue FAs after obesity surgery could be associated with changes in endogenous metabolism and diet.

Obstructive sleep apnea: the effect of bariatric surgery after 12 months. A prospective multicenter trial.

BACKGROUND: Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder, particularly in bariatric patients. It is known to be tightly linked with metabolic abnormalities and cardiovascular morbidity. Obesity is the most noteworthy individual risk factor for OSA. The aim of this study was to investigate the effect of a laparoscopic Roux-en-Y gastric bypass (LRYGB) on OSA one year after surgery. METHODS: In this prospective multicenter study standard overnight cardiorespiratory recording was conducted 12 months after bariatric surgery in 132 patients who had OSA in the baseline recording prior to the operation. The main outcome measures were changes in the prevalence of OSA and apnea-hypopnea index (AHI). In addition, the changes in anthropometric and demographic measurements including weight, body mass index (BMI), and waist and neck circumference were evaluated. A sleep symptom questionnaire was administered at baseline and at 12 months. RESULTS: The prevalence of OSA decreased from 71% at baseline to 44% at 12 months after surgery (p < 0.001). OSA was cured in 45% and cured or improved in 78% of the patients, but moderate or severe OSA still persisted in 20% of the patients after the operation. De novo OSA occurred in eight percent of the patients, and total AHI decreased from 27.8 events/h to 9.9 events/h (p < 0.001). CONCLUSIONS: LRYGB is effective in treating OSA. However, the findings demonstrate that a postoperative cardiorespiratory recording is needed in order to identify the patients with persistent moderate to severe OSA after the operation. CLINICAL TRIAL REGISTRATION: ClinalTrials.gov; No.: NCT01080404; URL: www.clinicaltrials.gov.

Prevalence of Obstructive Sleep Apnoea Among Patients Admitted for Bariatric Surgery. A Prospective Multicentre Trial.

BACKGROUND: Obesity has become one of the greatest public health concerns worldwide and is known to be the most important risk factor for obstructive sleep apnoea (OSA). Prevalence of OSA has increased over the last two decades, but it is estimated that the majority of cases still remain undiagnosed. The aim of this study was to investigate the prevalence of OSA in Finnish bariatric surgery candidates. METHODS: In this prospective multicentre study, standard overnight cardiorespiratory recording was conducted in 197 consecutive patients from three different hospitals. A sleep questionnaire was also administered. Anthropometric and demographic measurements included age, weight, body mass index (BMI) and waist and neck circumference. RESULTS: Altogether, 71 % of the patients were diagnosed with OSA. The prevalence was higher in males (90 %) than in females (60 %) (p < 0.001). In OSA patients' group, the mean neck and waist circumference was larger (p < 0.001) and the body weight higher (p < 0.01) than in non-OSA group. When separating patients by gender, a significant difference remained only concerning neck circumference in female patients. CONCLUSIONS: OSA is very common among bariatric surgery patients, especially in men. Considering this and the increased long-term morbidity and mortality generally related to OSA, a routine screening for OSA seems indicated in bariatric patients, particularly men.

Genetic risk score does not predict the outcome of obesity surgery.

BACKGROUND: We evaluated the benefit of using combined genetic risk score (GRS) of known single nucleotide polymorphisms (SNPs) for body mass index (BMI) and waist/hip ratio (WHR) in the prediction of weight loss and weight regain after obesity surgery. METHODS: A total of 163 consecutive morbidly obese individuals undergoing Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) in a single bariatric center in Finland were recruited. Fasting blood samples were drawn after 12 h of fasting before and 1 year after bariatric operation. Data for weight regain and medication were collected with a questionnaire after 3.1 ± 2.7 years (mean ± SD) follow-up. Nonalcoholic steatohepatitis (NASH) was diagnosed with liver histology. Twenty BMI- and 13 WHR-related SNPs were genotyped. Linear regression was used to identify factors predicting weight loss and weight regain. RESULTS: Lower baseline BMI predicted greater decline in BMI (p = 0.0005) and excess weight loss (EWL) (p = 0.009). In the multiple linear regression analysis age and BMI, explained the variance of EWL during the first year while GRS, sex, fasting plasma glucose, serum insulin and NASH diagnosis did not have any effect. None of the baseline clinical variables explained BMI regain. The combined GRS did not associate with weight or BMI at baseline, with 1-year changes or with weight regain between 1 year and an average of 3.1 years follow-up. CONCLUSIONS: In our study, we found that the genotype risk score does not predict weight loss after obesity surgery while lower baseline BMI predicted the greater weight loss.

Conjugated bile acids associate with altered rates of glucose and lipid oxidation after Roux-en-Y gastric bypass.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (RYGB) induces a more favorable metabolic profile than expected by weight loss alone. In this study, we investigated the effect of RYGB on serum bile acid levels and their relation to clinical outcomes. METHODS: We included 30 obese patients who underwent RYGB (BMI = 46.1 ± 5.9 kg/m(2)). Clinical measurements and laboratory determinations were performed before surgery and 1 year after surgery. Fasting serum bile acids were measured by an enzymatic method and individual bile acids were quantified by HLPC-tandem mass spectrometry. Indirect calorimetry was performed to measure the rates of energy expenditure and substrate oxidation. RESULTS: Fasting total serum bile acid levels increased twofold after RYGB (pre, 3.68 ± 2.03 vs. post, 7.06 ± 9.65 µmol/l, +92 %, p = 0.002). This increase in total bile acids was accompanied by a decrease in conjugated bile acids, which correlated with decreased glucose oxidation (r = 0.571, p = 0.002) and with increased lipid oxidation (r = -0.626, p = 0.0004). The change in taurine-conjugated bile acids correlated with altered DIO2 mRNA expression in adipose tissue (r = -0.498, p = 0.013) potentially linking bile acid conjugation to substrate oxidation through DIO2. CONCLUSIONS: Fasting serum bile acid levels increase after RYGB. More specifically, changes in bile acid conjugation after RYGB associate with altered energy metabolism.

Iron ore: from depletion to abundance.

Following World War II, Americans feared their iron ore supplies were depleted. The steel industry attempted to increase supplies by exploring foreign countries for new, high-grade hematite ores and experimenting with technology that upgraded low-grade domestic taconite ores into acceptable, but apparently uneconomical, pellets. Government did little at first, but the Korean War renewed fears of domestic resource exhaustion. Congress quickly enacted loan guarantees, rapid tax write-offs, and other tax policies that helped commercialize taconite pellets for national defense. These policies lingered long after the Korean War ended. Other policies bolstering taconite were enacted on the state level well after taconite had replaced hematite as industry's ore of choice. Understanding how government policies helped to develop pelletized lean iron ore may help in thinking about current policy suggestions aimed at easing our energy crisis or other mineral shortages. For taconite, too much government help came too late.

Iron ore: energy, labor, and capital changes with technology.

Resource gathering is depending on leaner crude ores. Iron ore mining typifies this trend. To make lean taconite iron ores useful required a technologic breakthrough-pelletization. The shift to iron ore pellets has the advantage that they require less energy and labor per ton of molten iron than high-grade naturally concentrated ores. Increased reliance on pellets causes a geographic shift of some jobs and environmental effects from blast furnaces to iron ore mines.