Changes in subcutaneous fat cell volume and insulin sensitivity after weight loss.

OBJECTIVE: Large subcutaneous fat cells associate with insulin resistance and high risk of developing type 2 diabetes. We investigated if changes in fat cell volume and fat mass correlate with improvements in the metabolic risk profile after bariatric surgery in obese patients. RESEARCH DESIGN AND METHODS: Fat cell volume and number were measured in abdominal subcutaneous adipose tissue in 62 obese women before and 2 years after Roux-en-Y gastric bypass (RYGB). Regional body fat mass by dual-energy X-ray absorptiometry; insulin sensitivity by hyperinsulinemic-euglycemic clamp; and plasma glucose, insulin, and lipid profile were assessed. RESULTS: RYGB decreased body weight by 33%, which was accompanied by decreased adipocyte volume but not number. Fat mass in the measured regions decreased and all metabolic parameters were improved after RYGB (P < 0.0001). Whereas reduced subcutaneous fat cell size correlated strongly with improved insulin sensitivity (P = 0.0057), regional changes in fat mass did not, except for a weak correlation between changes in visceral fat mass and insulin sensitivity and triglycerides. The curve-linear relationship between fat cell size and fat mass was altered after weight loss (P = 0.03). CONCLUSIONS: After bariatric surgery in obese women, a reduction in subcutaneous fat cell volume associates more strongly with improvement of insulin sensitivity than fat mass reduction per se. An altered relationship between adipocyte size and fat mass may be important for improving insulin sensitivity after weight loss. Fat cell size reduction could constitute a target to improve insulin sensitivity.

Omentectomy in addition to gastric bypass surgery and influence on insulin sensitivity: a randomized double blind controlled trial.

BACKGROUND & AIMS: Accumulation of visceral adipose tissue is associated with insulin resistance and cardio-vascular disease. The aim of this study was to elucidate whether removal of a large amount of visceral fat by omentectomy in conjunction with Roux en-Y gastric bypass operation (RYGB) results in enhanced improvement of insulin sensitivity compared to gastric bypass surgery alone. METHODS: Eighty-one obese women scheduled for RYGB were included in the study. They were randomized to RYGB or RYGB in conjunction with omentectomy. Insulin sensitivity was measured by hyperinsulinemic euglycemic clamp before operation and sixty-two women were also reexamined 2 years post-operatively. The primary outcome measure was insulin sensitivity and secondary outcome measures included cardio-metabolic risk factors. RESULTS: Two-year weight loss was profound but unaffected by omentectomy. Before intervention, there were no clinical or metabolic differences between the two groups. The difference in primary outcome measure, insulin sensitivity, was not significant between the non-omentectomy (6.7 ± 1.6 mg/kg body weight/minute) and omentectomy groups (6.6 ± 1.5 mg/kg body weight/minute) after 2 years. Nor did any of the cardio-metabolic risk factors that were secondary outcome measures differ significantly. CONCLUSION: Addition of omentectomy to gastric bypass operation does not give an incremental effect on long term insulin sensitivity or cardio-metabolic risk factors. The clinical usefulness of omentectomy in addition to gastric bypass operation is highly questionable. CLINICAL TRIAL REGISTRATION NUMBER: NCT01785134.

Variations in the size of the major omentum are primarily determined by fat cell number.

OBJECTIVE: Accumulation of visceral adipose tissue (VAT) is strongly linked to insulin resistance. Variations in the size of any adipose depot are determined by alterations in adipocyte volume and/or number. The individual contribution of each of the latter factors was determined in the major omentum, a fully resectable VAT depot. SUBJECTS: Total removal of the major omentum (omentectomy) was performed in conjunction with bariatric surgery in 55 obese patients. Tissue weight as well as mean adipocyte size and number in the omentum were determined. In subgroups, total VAT was estimated by computerized tomography (n = 17) or dual-energy x-ray absorptiometry (n = 34). RESULTS: The weight of the major omentum (on average 0.6 kg) correlated significantly with total VAT mass estimated by computerized tomography or dual-energy x-ray absorptiometry (r = 0.48-0.7; P < .01). Omental weight in relation to total body fat correlated with several features of the metabolic syndrome and inversely with serum-leptin (P < .001). Mean adipocyte size and total adipocyte number correlated strongly with omental weight (r = 0.6-0.8; P < .0001), irrespective of body mass index and total body fat mass, and accounted almost in total for interindividual variations in omental size. However, stepwise regression analysis demonstrated that adipocyte number was significantly (P < .0001) more important (62%) than adipocyte size (35%). CONCLUSION: The size of the major omentum is representative for VAT mass and correlates with a pernicious metabolic profile. Variations in omental weight are primarily determined by adipocyte number and to a lesser degree by adipocyte size, suggesting that increased VAT mass in obesity is predominantly dependent on adipocyte proliferation.

Increased visceral adipocyte lipolysis--a pathogenic role in nonalcoholic fatty liver disease?

CONTEXT: Obesity is a major risk factor for nonalcoholic fatty liver disease, but the primary pathophysiological mechanisms remain unclear. OBJECTIVE: The aim was to study the relative role of visceral and sc in vitro lipolysis for liver fat accumulation. PATIENTS: Eighteen morbidly obese women participated in the study. DESIGN: Hepatic triglyceride accumulation and abdominal visceral and sc fat area were assessed by computer tomography. Biopsies were taken from abdominal sc and visceral fat tissue. Basal and maximal lipolysis was measured using various lipolytic drugs acting at different steps in the lipolytic cascade. RESULTS: No difference in total body, visceral, or sc fat mass was found between patients with high, intermediate, or low amounts of liver fat. In patients with high liver fat content, there was an approximately 2-fold increase in visceral adipocyte maximal glycerol release induced by the different lipolytic agents (P = 0.002 to 0.01). Noradrenaline-mediated free fatty acid release from visceral adipocytes was also about twice as high in patients with high liver fat (P = 0.004). In contrast, in sc adipocytes, no relationship between liver fat content and either glycerol or free fatty acid release was found. CONCLUSIONS: We suggest a pathogenic role of visceral, but not sc, adipocyte lipolytic function in nonalcoholic fatty liver disease, independent of total body fat as well as abdominal fat distribution.

Glutathione and amino acid concentrations in human liver during short warm ischaemia and reperfusion: a pilot study.

Glutathione is a major antioxidant, and, in the present study, we investigated whether a clinical model of short warm ischaemia and reperfusion of the human liver during surgery would influence glutathione and amino acid metabolism. Previous studies in humans have demonstrated that ischaemia and reperfusion in skeletal muscle for up to 120 min have no major effect on muscle glutathione concentrations. Liver ischaemia and reperfusion in animals have demonstrated diverging results concerning glutathione metabolism. In the present study, six patients with liver malignancies, undergoing liver resection during warm ischaemia, were included. Liver biopsies were obtained from healthy appearing liver tissue from both lobes before ischaemia and at maximal ischaemia, and from the remaining liver lobe after 5, 10, 15, 20, 25 and 30 min of reperfusion. The biopsies were analysed for glutathione, amino acids and lactate. Median ischaemia time was 28 (range, 15-36) min. Lactate increased 266% at maximal ischaemia (P<0.05). No alterations in glutathione concentrations or the redox status of glutathione (GSH/total glutathione) were observed. Glutamate decreased 22% (P<0.05) at maximal ischaemia and increased thereafter 72% at 30 min of reperfusion (P<0.05). Alanine increased 105% at maximal ischaemia (P<0.05) and was normalized during reperfusion. BCAAs (branched-chain amino acids) increased 67% at maximal ischaemia (P<0.05). In conclusion, short-time ischaemia and reperfusion in the human liver did not affect glutathione concentrations, whereas changes were observed in amino acid concentrations during both ischaemia and reperfusion.

Effect of carbon dioxide pneumoperitoneum on development of atelectasis during anesthesia, examined by spiral computed tomography.

BACKGROUND: Anesthesia per se results in atelectasis development in the dependent regions of the lungs. The effect of pneumoperitoneum on atelectasis formation is not known. The aim of the current study was to measure by spiral computed tomography the effect of carbon dioxide pneumoperitoneum for laparoscopic surgery on the development of atelectasis, overall lung volume, and regional tissue volumes of gas and tissue. METHODS: Seven patients (American Society of Anesthesiologists physical status I), scheduled to undergo laparoscopic cholecystectomy, were observed. After induction of anesthesia, the patients were mechanically ventilated and positioned supine on the computed tomography table. Tomography of the lungs (10 mm spiral) was performed before and 10 min after induction of carbon dioxide pneumoperitoneum at an intraabdominal pressure of 11-13 mmHg. The Student t test was used for statistical analysis. A P value less than 0.05 was considered significant. RESULTS: Induction of pneumoperitoneum increased the mean atelectasis volume in the dependent lung regions by 66% (range, 11-170%). The overall lung volume and gas as well as tissue volume significantly decreased. Relative to the total lung volume, lung tissue volume increased, while gas volume decreased significantly. Both upper and lower lobes reacted the same way. A cranial displacement of the diaphragm between 1 and 3 cm (mean, 1.9 cm) was registered. CONCLUSION: Pneumoperitoneum at an intraabdominal pressure level of 11-13 mmHg increased the volume of atelectasis. Because lung tissue volume increased in the lung, there may have been an opening of previously closed vessels, which could explain previously seen increase in arterial oxygenation after induction of pneumoperitoneum.

Effectiveness of a new carrier-bound fibrin sealant versus argon beamer as haemostatic agent during liver resection: a randomised prospective trial.

BACKGROUND AND AIMS: A new carrier-bound fibrin sealant, TachoSil, is expected to be efficacious and safe as a haemostatic treatment in hepatic resection. DESIGN: A prospective, randomised, open and controlled multicentre trial with intraoperative as well as postoperative assessment of efficacy and a 1 month follow-up period. SETTING: Tertiary care centres. PATIENTS/METHODS: One hundred and twenty-one patients requiring secondary haemostasis during planned liver resection. Patients with coagulation disorders and patients with persistent major bleeding after primary haemostatic measures were excluded. INTERVENTION: Application of either carrier-bound fibrin sealant (n=59) or argon beamer (argon beam coagulator) (n=62) as secondary haemostatic treatment. MAIN OUTCOME MEASURE: Time to intraoperative haemostasis. RESULTS: There was a significant superiority of TachoSil over argon beamer with regard to time to haemostasis (3.9 min, median 3.0, range 3-20 min vs 6.3 min, median 4.0, range 3-39 min) (P=0.0007). Haemoglobin concentration of drainage fluid was significantly lower on day 2 after surgery in TachoSil patients (1.1 mmol/l) than in argon beamer patients (2.3 mmol/l) (P=0.012). Overall, the frequency and causality of adverse events did not differ between the two treatment groups. CONCLUSION: TachoSil is superior to argon beamer in obtaining effective and fast intraoperative haemostasis. The safety data show TachoSil to be tolerable and safe for haemostatic treatment in liver resection.

Indium-111-labelled donor-lymphocyte infusion by way of hepatic artery and radio-frequency ablation against liver metastases of renal and colon carcinoma after allogeneic hematopoietic stem-cell transplantation.

BACKGROUND: In patients with metastatic solid cancer, antitumor effects occur after allogeneic stem-cell transplantation (SCT). However, this treatment is not as effective in the liver as against pulmonary and lymph-node metastases. To intensify the effect of donor-lymphocyte infusions (DLI) against liver metastases, intra-arterial (IA) cell injection by way of the hepatic artery (HA) can be used. METHODS: To trace infused cells, three patients with colorectal, three with renal, and one with breast carcinoma were treated with Indium-111 (111-In)-oxinate-labeled lymphocytes. Four patients received the DLI IA, all after radio-frequency ablation (RFA) of liver metastases. Three patients with other metastases received 111-In DLI intravenously (IV). One of them had RFA before SCT. RESULTS: Localization of the IA 111-In DLI activity on scintigrams homed to the liver. After IA injection, the liver to sternum ratio of radioactivity was higher compared with IV injection. Cells (CD3+, 19+, and 56+) of donor origin in biopsies of liver metastasis in two patients treated with IA injection increased to 80% to 100%. Two of four patients treated using the IA DLI showed stable size and number of liver metastases for 5 and 21 months, respectively. Both are alive 18 and 34 months after SCT. Two of three patients receiving DLI IV are doing well, with a stable metastatic disease or still without metastases 21 and 20 months after cell infusions (26 and 34 months after SCT), respectively. Three patients died because of progressive disease. CONCLUSION: When infused by way of the HA, 111-In-labeled lymphocytes home to the liver and its metastases. The liver metastasis infiltrating cells of donor origin increased. DLI by way of the HA combined with RFA may be used to treat liver metastases after SCT.

The synthesis rate of albumin decreases during laparoscopic surgery.

In previous studies, a decline in total liver protein synthesis during elective laparoscopic surgery has been observed. However, when albumin synthesis was measured in parallel no apparent influence of the procedure was detected. The aim of the present study was to specifically investigate the effect of a laparoscopic procedure on albumin synthesis. Female (n = 9) patients scheduled for elective laparoscopic cholecystectomy as a consequence of cholecystolithiasis were investigated. The fractional synthesis rate (FSR) of albumin was investigated twice in each patient, before and during surgery (2-3 h apart), employing L-[2H5]phenylalanine and gas chromatography mass spectrometry. The FSR of albumin decreased from 7.3 +/- 1.2% per day before surgery to 6.2 +/- 1.4% per day during the procedure (P<0.01), whereas the corresponding absolute synthesis rates of albumin decreased from 114 +/- 24 to 86 +/- 16 mg kg(-1) day(-1), respectively (P<0.001). In conclusion, the synthesis rate of albumin decreased during a laparoscopic surgery procedure. However, the characteristics for this decrease differ from those previously observed for total liver protein synthesis.

Animal models for treatment of unresectable liver tumours: a histopathologic and ultra-structural study of cellular toxic changes after electrochemical treatment in rat and dog liver.

INTRODUCTION: Electrochemical treatment (EChT) has been taken under serious consideration as being one of several techniques for local treatment of malignancies. The advantage of EChT is the minimal invasive approach and the absence of serious side effects. Macroscopic, histopathological and ultra-structural findings in liver following a four-electrode configuration (dog) and a two-electrode EChT design (dog and rat) were studied. MATERIALS AND METHODS: 30 female Sprague-Dawley rats and four female beagle dogs were studied with EChT using Platinum:Iridium electrodes and the delivered dose was 5, 10 or 90 C (As). After EChT, the animals were euthanized. RESULTS: The distribution of the lesions was predictable, irrespective of dose and electrode configuration. Destruction volumes were found to fit into a logarithmic curve (dose-response). Histopathological examination confirmed a spherical (rat) and cylindrical/ellipsoidal (dog) lesion. The type of necrosis differed due to electrode polarity. Ultra-structural analysis showed distinct features of cell damage depending on the distance from the electrode. Histopathological and ultra-structural examination demonstrated that the liver tissue close to the border of the lesion displayed a normal morphology. CONCLUSIONS: The in vivo dose-planning model is reliable, even in species with larger tissue mass such as dogs. A multi-electrode EChT-design could obtain predictable lesions. The cellular toxicity following EChT is clearly identified and varies with the distance from the electrode and polarity. The distinct border between the lesion and normal tissue suggests that EChT in a clinical setting for the treatment of liver tumours can give a reliable destruction margin.

Cellular toxicity induced by different pH levels on the R3230AC rat mammary tumour cell line. An in vitro model for investigation of the tumour destructive properties of electrochemical treatment of tumours.

INTRODUCTION: The aim of this study was to evaluate the cellular toxicity of different pH levels on the R3230AC mammary tumour cell line (clone-D) in vitro and to determine in what way the pH affects the tumour cells. The results could be used to interpret the cell damaging effects seen in electrochemical treatment of tumours (EChT), where pH alteration in tissue is the major event. METHODS: Tumour cells were treated with pH 3.5, 5, 7, 9, 10 and 11 for 10, 20 or 30 min, respectively, followed by studies with the viability assay 3-(4,5-dimethylthiazol-2-yl)-2,5,-diphenyl tetrazolium bromide (methyltetrazolium (MTT)), morphological observation in phase contrast microscope (PCM) and light microscope, nucleotide analogue incorporation (BrdU; 5-Brdmo-2'-deoxyuridine), Caspase-3 activity measurement and detection of DNA fragmentation by an agarose gel electrophoresis. RESULTS: In the viability assay, it was found that different pH levels had cytotoxic effects; these effects were dependent on the pH value and on the time of exposure at a given pH. Morphologically, cells in pH 3.5 and 5 had shrunk, were rounded and had condensed chromatin, whereas prominent cell swelling and nuclear expansion were seen in the pH 9- and 10-treated cells. Gross cytolysis was found in pH 11. A BrdU incorporation assay indicated that proliferation rate is inhibited markedly both with decreasing and increasing pH. Significant Caspase-3 activity was found in pH 3.5 and 5 groups. Caspase-3 levels for the alkaline exposure were equal or below the normal control. DNA ladder formation, a characteristic of apoptosis, was only visualised in the treatment of pH 3.5 for 30 min. CONCLUSIONS: pH changes inhibit cell proliferation and decrease cell viability. The pathway of killing tumour cell in low pH probably has at least two directions: apoptosis and cell necrosis, whereas high pH results in only cell necrosis. The study suggests that low pH environment can induce apoptosis in unphysiological condition comparable with tissue pH at EChT. In addition, it seems that R3230AC mammary tumour cells are more tolerant to high pH than to acidic changes. This supports the theory that anodic EChT should be more efficient than cathodic.

Major gender differences in the lipolytic capacity of abdominal subcutaneous fat cells in obesity observed before and after long-term weight reduction.

The influence of obesity on the lipolytic capacity of isolated sc fat cells was studied prospectively in 13 women and 10 men, all obese, but otherwise healthy, before and 2 and 3 yr after weight reduction by bariatric surgery. Nonobese subjects (25 women and 17 men) without a family history of obesity served as the control group. Lipolytic capacity was determined after stimulation at different steps of the lipolytic cascade with noradrenaline, isoprenaline, forskolin, and (Bu)(2)AMP. Bariatric surgery was followed by a marked and similar reduction of body mass index and fat cell volume (approximately 40%) in both genders. Before weight loss, lipolytic capacity per cell was elevated in obese women and decreased to normal levels after weight reduction at 2 and 3 yr. However, lipolytic capacity per fat cell surface area was not changed in obese women. In obese men, lipolytic capacity per cell was almost the same as in lean men and was not influenced by weight reduction. Lipolytic capacity was related to fat cell size in women (P = 0.0008; r = 0.58), but not in men (P = 0.67; r = 0.086). The protein content of hormone-sensitive lipase, which determines lipolytic capacity, was significantly lower in obese men and women and increased slightly after weight reduction in men only. Thus, in women, but not in men, the adipocyte lipolytic capacity is influenced by obesity and weight reduction, probably due to changes in fat cell size. These gender differences are not related to the amount of hormone-sensitive lipase protein in adipocytes.

A unique defect in the regulation of visceral fat cell lipolysis in the polycystic ovary syndrome as an early link to insulin resistance.

The etiology of polycystic ovary syndrome (PCOS) is unknown. However, PCOS has a strong resemblance to the insulin resistance (metabolic) syndrome, where an increased rate of visceral fat cell lipolysis is believed to play a pathophysiological role. We hypothesized that primary defects in visceral lipolysis might also exist in PCOS. Ten young, nonobese, and otherwise healthy PCOS women were compared with 13 matched control women. In vitro lipolysis regulation and stoichiometric properties of the final step in lipolysis activation, namely the protein kinase A (PKA)-hormone sensitive lipase (HSL) complex, were investigated in isolated visceral (i.e., omental) fat cells. Body fat distribution and circulating levels of insulin, glucose, and lipids were normal in PCOS women. However, in vivo insulin sensitivity was slightly decreased (P = 0.03). Catecholamine-induced adipocyte lipolysis was markedly (i.e., about twofold) increased in PCOS women due to changes at the postreceptor level, although there was no change in the antilipolytic properties of visceral fat cells. Western blot analyses of visceral adipose tissue showed twofold increased levels of the catalytic and the regulatory Ialpha components of PKA. In contrast, the regulatory RIIbeta component of PKA was almost 50% decreased in visceral adipose tissue in PCOS women. Recent studies on genetically modified mice have shown that a similar transition in the regulatory PKA units induces an increased lipolytic response to catecholamines. Further analysis showed that the level of HSL-short, an enzymatically inactive splice form of HSL, was decreased in PCOS (P < 0.01). The altered lipolysis in PCOS is different from that observed in visceral fat cells in the insulin resistance syndrome that occurs at the level of adrenergic receptors. We concluded that increased catecholamine-induced lipolysis in visceral fat cells may be due to unique alterations in the stoichiometric properties of the adipose PKA-HSL holoenzymes. This could be an early and possibly primary lipolysis defect in PCOS.