Effect of insulin on natriuretic peptide gene expression in porcine heart.

Gut hormones affect cardiac function and contractility. In this study, we examined whether insulin affects the cardiac atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) gene expression and release of proANP-derived peptides in pigs. Anaesthetized pigs were included in an experimental study comparing the effect of hyperinsulinemia in 15 pigs submitted to two different protocols versus 11 control pigs receiving saline infusion. Phosphorylation of Akt on Thr308 was determined by western blotting with a pAkt-Thr308 antibody. The mRNA contents of ANP and BNP were determined with real-time PCR; plasma and cardiac tissue proANP was measured with an immunoluminometric assay targeted against the mid-region of the propeptide and a processing-independent assay. Insulin stimulation increased phosphorylation of Akt Thr308 in both left atrium and left ventricle of porcine hearts (p < 0.005). No change was observed in ANP and BNP mRNA contents in the right or left atrium. BNP mRNA contents in the left ventricle, however, decreased 3-fold (p = 0.02) compared to control animals, whereas the BNP mRNA content in the right ventricle as well as ANP mRNA content in the right and left ventricle did not change following hyperinsulinemia. Moreover, the peptide contents did not change in the four cardiac chambers. Finally, proANP concentrations in plasma did not change during the insulin infusion compared to the control animals. These results suggest that insulin does not have direct effect on atrial natriuretic peptide expression but may have a role in the left ventricle.

Screening for a Simple and Effective Indicator of Insulin Resistance in Chinese Reproductive-Aged Women, with the Insulin Clamp Technique as a Reference.

Background: Applying the hyperinsulinemic-euglycemic clamp to estimate insulin resistance (IR) is accurate but time-consuming, so identifying a simple and effective index for IR is vitally important. The present study aimed to compare the lipid accumulation product (LAP), visceral adiposity index (VAI), body mass index (BMI), waist circumference (WC), homeostasis model assessment of insulin resistance (HOMA-IR), and Chinese visceral adiposity index (CVAI) using the hyperinsulinemic-euglycemic clamp as a reference and to screen a simple and effective indicator for IR in Chinese women of childbearing age. Methods: The present study included a cross-sectional study of 537 reproductive-aged women and an interventional study of 90 randomly chosen polycystic ovarian syndrome (PCOS) women. Physical, laboratory, and hyperinsulinemic-euglycemic clamp were completed, and the BMI, WC, LAP, VAI, CVAI, and HOMA-IR were calculated. A linear correlation and a receiver operating characteristic curve were performed. After intervention with metformin, the effects were estimated in the third month. Results: PCOS women had worse glycometabolism, serum lipid metabolism and IR, and higher prevalence rates of metabolic disorders than those without PCOS. The CVAI was strongly associated with the M value (r = -0.6953, P < 0.0001) and outperformed other parameters with the largest area under the curve (0.903) and Youden index (71.07%) for IR diagnosis in Chinese reproductive-aged women, and the diagnostic point was >28.5. After 3 months of metformin therapy, IR improved with remarkable increases in M value and reductions in the CVAI. Conclusion: The CVAI can be used as an appropriate surrogate indicator for the hyperinsulinemic-euglycemic clamp to identify IR in Chinese women of childbearing age. The interventional trial part of this study has been registered as a clinical trial (no. ChiCTR-IIR-16007901).

Lipids and insulin regulate mitochondrial-derived peptide (MOTS-c) in PCOS and healthy subjects.

OBJECTIVE: Polycystic ovarian syndrome (PCOS) is a heterogeneous endocrine disorder associated with mitochondrial dysfunction and insulin resistance (IR). MOTS-c, a mitochondrial peptide, promotes insulin sensitivity (IS) through activating AKT and AMPK-dependent pathways. The current study was designed to examine the response of MOTS-c to lipids (intralipid) followed by insulin in PCOS and healthy subjects. METHODS: All subjects underwent 5-hour intralipid/saline infusion with a hyperinsulinemic-euglycaemic clamp in the final 2 hours. Plasma samples were collected to measure circulating MOTS-c using a commercial ELISA kit. Subsequently, this was repeated following an eight-week exercise intervention. RESULTS: Intralipid significantly increased plasma MOTS-c both in controls and PCOS subjects, whilst the insulin infusion blunted the intralipid-induced response seen for both lipids and MOT-c. Intralipid elevated plasma MOTS-c to 232 ± 124% of basal in control (P < 0.01) and to 349 ± 206% of basal in PCOS (P < 0.001) subjects. Administration of insulin suppressed intralipid-induced MOTS-c from 232 ± 124% to 165 ± 97% (NS) in control and from 349 ± 206% to 183 ± 177% (P < 0.05) in PCOS subjects, respectively. Following exercise, intralipid elevated plasma MOTS-c to 305 ± 153% of basal in control (P < 0.01) and to 215 ± 103% of basal in PCOS (P < 0.01) subjects; insulin suppressed intralipid-induced MOTS-c only in controls. CONCLUSIONS: In conclusion, this is the first study to show increased lipid enhanced circulating MOTS-c whilst insulin attenuated the MOTS-c response in human. Further, eight weeks of moderate exercise training did not show any changes in circulating MOTS-c levels in healthy controls and in women with PCOS.

The clinical course and potential underlying mechanisms of everolimus-induced hyperglycemia.

The mechanistic target of rapamycin (mTOR) inhibitor everolimus is an antitumor agent known to cause hyperglycemia. However, the clinical course of everolimus-induced hyperglycemia, its pathophysiological basis, and the treatment strategy are not clear. In this case series report, we present the clinical course of everolimus-induced hyperglycemia in four patients. Hyperglycemia occurred 3-8 weeks after the administration of everolimus irrespective of the body mass index (range, 21.3-29.1 kg/m2) or pre-existing diabetes. Insulin or insulin secretagogues were required for glycemic control in most of the patients. Of note, the hyperglycemia was reversible in all patients, and none of the patients required anti-diabetic agents to achieve adequate glycemic control after cessation of everolimus therapy. To investigate the underlying mechanism of everolimus-induced hyperglycemia, we assessed insulin secretion and sensitivity by 75 g oral glucose tolerance test, arginine challenge test, and/or hyperinsulinemic-euglycemic clamp study using stable isotope-labeled glucose tracer in two patients. Everolimus did not affect insulin sensitivity in the liver, skeletal muscle, or the adipose tissue. In contrast, everolimus impaired insulin secretion and thereby increased basal hepatic glucose production. These findings further our understanding of the role of mTOR in glucose homeostasis in humans and provide insights for treatment strategies against everolimus-induced hyperglycemia.

In Vivo Decoding Mechanisms of the Temporal Patterns of Blood Insulin by the Insulin-AKT Pathway in the Liver.

Cells respond to various extracellular stimuli through a limited number of signaling pathways. One strategy to process such stimuli is to code the information into the temporal patterns of molecules. Although we showed that insulin selectively regulated molecules depending on its temporal patterns using Fao cells, the in vivo mechanism remains unknown. Here, we show how the insulin-AKT pathway processes the information encoded into the temporal patterns of blood insulin. We performed hyperinsulinemic-euglycemic clamp experiments and found that, in the liver, all temporal patterns of insulin are encoded into the insulin receptor, and downstream molecules selectively decode them through AKT. S6K selectively decodes the additional secretion information. G6Pase interprets the basal secretion information through FoxO1, while GSK3ß decodes all secretion pattern information. Mathematical modeling revealed the mechanism via differences in network structures and from sensitivity and time constants. Given that almost all hormones exhibit distinct temporal patterns, temporal coding may be a general principle of system homeostasis by hormones.

Circulating ApoJ is closely associated with insulin resistance in human subjects.

OBJECTIVE: Insulin resistance is a major risk factor for type 2 diabetes. ApolipoproteinJ (ApoJ) has been implicated in altered pathophysiologic states including cardiovascular and Alzheimer's disease. However, the function of ApoJ in regulation of glucose homeostasis remains unclear. This study sought to determine whether serum ApoJ levels are associated with insulin resistance in human subjects and if they change after interventions that improve insulin sensitivity. METHODS: Serum ApoJ levels and insulin resistance status were assessed in nondiabetic (ND) and type 2 diabetic (T2D) subjects. The impacts of rosiglitazone or metformin therapy on serum ApoJ levels and glucose disposal rate (GDR) during a hyperinsulinemic/euglycemic clamp were evaluated in a separate cohort of T2D subjects. Total ApoJ protein or that associated with the HDL and LDL fractions was measured by immunoblotting or ELISA. RESULTS: Fasting serum ApoJ levels were greatly elevated in T2D subjects (ND vs T2D; 100±8.3 vs. 150.6±8.5AU, P<0.0001). Circulating ApoJ levels strongly correlated with fasting glucose, fasting insulin, HOMA-IR, and BMI. ApoJ levels were significantly and independently associated with HOMA-IR, even after adjustment for age, sex, and BMI. Rosiglitazone treatment in T2D subjects resulted in a reduction in serum ApoJ levels (before vs. after treatment; 100±13.9 vs. 77±15.2AU, P=0.015), whereas metformin had no effect on ApoJ levels. The change in ApoJ levels during treatment was inversely associated with the change in GDR. Interestingly, ApoJ content in the LDL fraction was inversely associated with HOMA-IR. CONCLUSION: Serum ApoJ levels are closely correlated with the magnitude of insulin resistance regardless of obesity, and decrease along with improvement of insulin resistance in response only to rosiglitazone in type 2 diabetes.

Insulin Secretion and Insulin Sensitivity Before and After Surgical Treatment of Pheochromocytoma or Paraganglioma.

Context: Pheochromocytoma and paraganglioma are catecholamine-producing tumors that often impair glucose tolerance. The effects of these tumors on insulin sensitivity and insulin secretion in patients have remained unclear, however. Objective: To characterize the influence of pheochromocytoma or paraganglioma on glucose tolerance, we comprehensively analyzed various parameters related to insulin secretion or insulin sensitivity in patients with these tumors. Design: Hyperglycemic and hyperinsulinemic-euglycemic clamps, as well as an oral glucose tolerance test (OGTT), were performed in patients before and after tumor excision. Setting: Patients underwent metabolic analyses on admission to Kobe University Hospital. Patients: Eleven patients with pheochromocytoma and two with paraganglioma were examined. Intervention: None. Main Outcome Measures: We evaluated various parameters related to insulin secretion or insulin sensitivity as determined by an OGTT and by hyperglycemic and hyperinsulinemic-euglycemic clamp analyses. Results: Surgical treatment of the tumor reduced urinary catecholamine excretion and improved glucose tolerance. The insulinogenic index, but not total insulin secretion, measured during the OGTT as well as the first phase, but not the second phase, of insulin secretion during the hyperglycemic clamp were improved after surgery. The insulin sensitivity index determined during the hyperinsulinemic-euglycemic clamp remained unchanged after surgery. Conclusion: These results suggest pheochromocytoma and paraganglioma impair glucose tolerance primarily through impairment of insulin secretion-in particular, that of the early phase of the insulin secretory response. A prospective study with more patients is warranted to further confirm these results.

Variable reliability of surrogate measures of insulin sensitivity after Roux-en-Y gastric bypass.

Roux-en-Y gastric bypass (RYGB) induces weight loss and improves insulin sensitivity when evaluated by the hyperinsulinemic-euglycemic clamp (HEC). Surrogate indices of insulin sensitivity calculated from insulin and glucose concentrations at fasting or after an oral glucose tolerance test (OGTT) are frequently used, but have not been validated after RYGB. Our aim was to evaluate whether surrogate indices reliably estimate changes in insulin sensitivity after RYGB. Four fasting surrogates (inverse-HOMA-IR, HOMA2-%S, QUICKI, revised-QUICKI) and three OGTT-derived surrogates (Matsuda, Gutt, OGIS) were compared with HEC-estimated peripheral insulin sensitivity (Rd or Rd/I, depending on how the index was originally validated) and the tracer-determined hepatic insulin sensitivity index (HISI) in patients with preoperative type 2 diabetes (n = 10) and normal glucose tolerance (n = 10) 1 wk, 3 mo, and 1 yr postoperatively. Post-RYGB changes in inverse-HOMA-IR and HOMA2-%S did not correlate with changes in Rd at any visit, but were comparable to changes in HISI at 1 wk. Changes in QUICKI and revised-QUICKI correlated with Rd/I after surgery. Changes in the Matsuda and Gutt indices did not correlate with changes in Rd/I and Rd, respectively, whereas OGIS changes correlated with Rd changes at 1 yr post-RYGB. In conclusion, surrogate measures of insulin sensitivity may not reflect results obtained with gold standard methodology after RYGB, underscoring the importance of critical reflection when surrogate endpoints are used. Fasting surrogate indices may be particularly affected by post-RYGB changes in insulin clearance, whereas the validity of OGTT-derived surrogates may be compromised by surgical rearrangements of the gut.

Metabolic and histological implications of intrahepatic triglyceride content in nonalcoholic fatty liver disease.

The cut-off point of intrahepatic triglyceride (IHTG) content to define nonalcoholic fatty liver disease (NAFLD) by proton magnetic resonance spectroscopy (1 H-MRS) was established based on the 95th percentile in a group of healthy individuals (i.e., ≥5.56%). Whether this threshold correlates with metabolic and histological changes and whether a further accumulation of IHTG is associated with worsening of these parameters has not been properly assessed in a large cohort of patients. In this cross-sectional study, 352 subjects were carefully characterized with the following studies: liver 1 H-MRS; euglycemic insulin clamp with measurement of glucose turnover; oral glucose tolerance test; and a liver biopsy. Hepatic insulin sensitivity (suppression of endogenous glucose production by insulin) was affected early on after IHTG content was ∼1.5% and remained uniformly impaired (∼40%-45%), regardless of further IHTG accumulation. Skeletal muscle insulin sensitivity showed a gradual impairment at low degrees of IHTG accumulation, but remained unchanged after IHTG content reached the ∼6 ± 2% threshold. A similar pattern was observed for metabolic changes typically associated with NAFLD, such as hypertriglyceridemia and low high-density lipoprotein cholesterol (HDL-C). In contrast, adipose tissue insulin sensitivity (suppression of free fatty acids by insulin) showed a continuous worsening across the spectrum of IHTG accumulation in NAFLD (r = -0.38; P < 0.001). Histological severity of liver disease (inflammation, ballooning, and fibrosis) was not associated with the amount of IHTG content. CONCLUSION: IHTG accumulation is strongly associated with adipose tissue insulin resistance (IR), supporting the current theory of lipotoxicity as a driver of IHTG accumulation. Once IHTG accumulation reaches ∼6 ± 2%, skeletal muscle IR, hypertriglyceridemia, and low HDL-C become fully established. Histological activity appears to have an early threshold and is not significantly influenced by increasing amounts of IHTG accumulation. (Hepatology 2017;65:1132-1144).

Glucagon-like peptide 1 decreases lipotoxicity in non-alcoholic steatohepatitis.

BACKGROUND & AIMS: Insulin resistance and lipotoxicity are pathognomonic in non-alcoholic steatohepatitis (NASH). Glucagon-like peptide-1 (GLP-1) analogues are licensed for type 2 diabetes, but no prospective experimental data exists in NASH. This study determined the effect of a long-acting GLP-1 analogue, liraglutide, on organ-specific insulin sensitivity, hepatic lipid handling and adipose dysfunction in biopsy-proven NASH. METHODS: Fourteen patients were randomised to 1.8mg liraglutide or placebo for 12-weeks of the mechanistic component of a double-blind, randomised, placebo-controlled trial (ClinicalTrials.gov-NCT01237119). Patients underwent paired hyperinsulinaemic euglycaemic clamps, stable isotope tracers, adipose microdialysis and serum adipocytokine/metabolic profiling. In vitro isotope experiments on lipid flux were performed on primary human hepatocytes. RESULTS: Liraglutide reduced BMI (-1.9 vs. +0.04kg/m(2); p<0.001), HbA1c (-0.3 vs. +0.3%; p<0.01), cholesterol-LDL (-0.7 vs. +0.05mmol/L; p<0.01), ALT (-54 vs. -4.0IU/L; p<0.01) and serum leptin, adiponectin, and CCL-2 (all p<0.05). Liraglutide increased hepatic insulin sensitivity (-9.36 vs. -2.54% suppression of hepatic endogenous glucose production with low-dose insulin; p<0.05). Liraglutide increased adipose tissue insulin sensitivity enhancing the ability of insulin to suppress lipolysis both globally (-24.9 vs. +54.8pmol/L insulin required to ½ maximally suppress serum non-esterified fatty acids; p<0.05), and specifically within subcutaneous adipose tissue (p<0.05). In addition, liraglutide decreased hepatic de novo lipogenesis in vivo (-1.26 vs. +1.30%; p<0.05); a finding endorsed by the effect of GLP-1 receptor agonist on primary human hepatocytes (24.6% decrease in lipogenesis vs. untreated controls; p<0.01). CONCLUSIONS: Liraglutide reduces metabolic dysfunction, insulin resistance and lipotoxicity in the key metabolic organs in the pathogenesis of NASH. Liraglutide may offer the potential for a disease-modifying intervention in NASH.

Twenty-four hour hyperinsulinemic-euglycemic clamp improves postoperative nitrogen balance only in low insulin sensitivity patients following cardiac surgery.

BACKGROUND: Critically ill patients often suffer from a protein catabolic state. The aim of this study was to demonstrate that nitrogen balance (NB) in cardiac patients admitted to the intensive care unit (ICU) is related to their insulin sensitivity level and that supraphysiologic doses of insulin can restore anabolism. MATERIALS AND METHODS: Twenty-eight patients that were admitted to ICU in enteral and/or parenteral nutrition have been enrolled in this study. All patients received a standard nutrition protocol for at least 3 days before starting the study. These patients received either enteral or parenteral nutrition based on 1.4 kcal/kg/h and 1.1 g/kg/24 h of proteins. Participants were studied for three 24 h periods (P1 , P2 , and P3 ). Twenty-four hour NB was calculated from urinary urea nitrogen excretion, fixed protein and energy intake during each of the three periods (P1 , P2 , and P3 ). Simultaneous to P2, a 24 h hyperinsulinemic-euglycemic clamp (HEC) was performed to determine patients' insulin sensitivity (IS) or insulin resistance (IR), as well as the impact of high doses of insulin on NB. RESULTS: Nitrogen balance remained consistently positive in the IS group regardless of the clamp. In IR patients, NB was negative before the clamp and became positive during P2 and P3 . Insulin sensitivity improved during the HEC in IR patients (P < 0.001). CONCLUSIONS: A negative NB was found only in insulin resistant patients admitted to the ICU for more than 7 days. A 24-h period HEC improved NB in these patients.

Intra-operative administration of low-dose IV glucose attenuates post-operative insulin resistance.

BACKGROUND & AIMS: Insulin sensitivity often decreases after surgery in spite of normal insulin secretion, and may worsen the outcome. This post-operative insulin resistance increases according to the magnitude of surgical invasion. However, supplementation of carbohydrates before surgery attenuates the post-operative insulin resistance. This study aimed to investigate the effect of intra-operative administration of low-dose glucose on the post-operative insulin resistance. METHODS: Patients undergoing maxillofacial surgery were randomly assigned to two groups throughout the surgical procedure: The glucose group receiving acetated Ringer solution with 1.5% glucose and the control group receiving acetated Ringer solution without glucose. Insulin resistance quantified by the mean glucose infusion rate (the glucose infusion rate) was evaluated by glucose clamp using the STG-22TM instrument on the previous day and on the next day of surgery. Blood glucose level was monitored continuously during surgery. In addition, serum insulin, ketone bodies and 3-methylhistidine were measured during perioperative period. RESULTS: Patients in the glucose group (n=11) received 0.15 ± 0.06 g/kg/h of glucose during surgery, while patients in the control group (n=11) received no glucose. In both groups, however, the mean blood glucose levels were maintained stable at less than 150 mg/dL during and after surgery. The serum ketone bodies significantly increased after surgery in the control group (p=0.0035), while it decreased significantly in the glucose group (p=0.043). The reduction rate in the glucose infusion rate was significantly lower in the glucose group, 43.3 ± 20.7%, than that in the control group, 57.7 ± 9.3% (p=0.041). CONCLUSIONS: Intra-operative small-dose of glucose administration may suppress ketogenesis and attenuate the post-operative insulin resistance without causing hyperglycemia.

Insulin resistance and increased muscle cytokine levels in patients with mitochondrial myopathy.

CONTEXT: Mitochondrial dysfunction has been proposed to cause insulin resistance and that might stimulate cytokine production. OBJECTIVE: The objective of the study was to elucidate the association between mitochondrial myopathy, insulin sensitivity, and cytokine levels in muscle. DESIGN AND SETTING: This was an experimental, controlled study in outpatients. PARTICIPANTS: Eight overnight-fasted patients (P) with various inherited mitochondrial myopathies and eight healthy subjects (C) matched for sex, age, weight, height, and physical activity participated in the study. INTERVENTIONS: The intervention included a 120-minute hyperinsulinemic, euglycemic clamp. Another morning, microdialysis of both vastus lateralis muscles for 4 hours, including one-legged, knee extension exercise for 30 minutes, was performed. MAIN OUTCOME MEASURES: Glucose infusion rate during 90-120 minutes of insulin infusion was measured. Cytokine concentrations in dialysate were also measured. RESULTS: Muscle strength, percentage fat mass, and creatine kinase in plasma did not differ between groups. The maximal oxygen uptake was 21 ± 3 (SE) (P) and 36 ± 3(C) mL/kg·min (2P < .05). Basal insulin, C-peptide, and glucagon were higher in P (55 ± 10, 980 ± 92, and 102 ± 13 pM) than in C (36 ± 12, 712 ± 98, and 44 ± 10 pM) (two-sided significance testing [2P ]< .05). The homeostasis model assessment insulin sensitivity index and glucose infusion rate (6.8 ± 1.0 vs 9.4 ± 1.3 mg/min·kg) were lower, and free fatty acids and glycerol at 120 minutes were higher in P vs C (2P < .05). Dialysate concentrations of TNF-α, IL-6, IL-8, IL-10, and monocyte chemoattractant protein-1 were higher in P vs C (2P < .05). Dialysate concentrations of these cytokines and of IL-1 receptor antagonist increased during exercise (2P < .05), identically in P and C. No differences existed in plasma cytokine concentrations. CONCLUSIONS: In patients with a variety of mitochondrial myopathies, insulin sensitivity of muscle, adipose tissue, and pancreatic A cells is reduced, supporting that mitochondrial function influences insulin action. Furthermore, a local, low-grade inflammation of potential clinical importance exists in the muscle of these patients.

Quantifying insulin sensitivity and entero-insular responsiveness to hyper- and hypoglycemia in ferrets.

Ferrets are an important emerging model of cystic fibrosis related diabetes. However, there is little documented experience in the use of advanced techniques to quantify aspects of diabetes pathophysiology in the ferret. Glycemic clamps are the gold standard technique to assess both insulin sensitivity and insulin secretion in humans and animal models of diabetes. We therefore sought to develop techniques for glycemic clamps in ferrets. To assess insulin sensitivity, we performed euglycemic hyperinsulinemic clamps in 5-6 week old ferrets in the anesthetized and conscious states. To assess insulin secretion, we performed hyperglycemic clamps in conscious ferrets. To evaluate responsiveness of ferret islet and entero-insular hormones to low glucose, a portion of the hyperglycemic clamps were followed by a hypoglycemic clamp. The euglycemic hyperinsulinemic clamps demonstrated insulin responsiveness in ferrets similar to that previously observed in humans and rats. The anesthetic isoflurane induced marked insulin resistance, whereas lipid emulsion induced mild insulin resistance. In conscious ferrets, glucose appearance was largely suppressed at 4 mU/kg/min insulin infusion, whereas glucose disposal was progressively increased at 4 and 20 mU/kg/min insulin. Hyperglycemic clamp induced first phase insulin secretion. Hypoglycemia induced a rapid diminishment of insulin, as well as a rise in glucagon and pancreatic polypeptide levels. The incretins GLP-1 and GIP were affected minimally by hyperglycemic and hypoglycemic clamp. These techniques will prove useful in better defining the pathophysiology in ferrets with cystic fibrosis related diabetes.

Safety and efficacy of intensive intraoperative glycaemic control in cardiopulmonary bypass surgery: a randomised trial.

BACKGROUND: This study aimed to determine the safety and efficacy of intraoperative intensive glycaemic treatment with modified glucose-insulin-potassium solution by hyperinsulinemic normoglycaemic clamp in cardiopulmonary bypass surgery patients. We hypothesised that the treatment would reduce infection rates in this group of patients. METHODS: A prospective, randomised, double-blind trial was conducted in cardiopulmonary bypass surgery patients. A total of 199 adult patients (out of a planned 400) were randomly allocated to intensive or conventional treatment with target glucose levels of 4.4-8.3 mmol/l and < 13.8 mmol/l, respectively. The primary outcomes were clinical infection and cytokine levels, including interleukin (IL)-6 and IL-10. The secondary outcomes were morbidity and mortality. RESULTS: The study was terminated early because of safety concerns (hypoglycaemia). The clinical post-operative infection rate was 17% in the intensive group and 13% in the conventional group (P = 0.53). The proportion of patients with hypoglycaemia was significantly higher in the intensive group (23%) compared with the conventional group (3%) (P < 0.001). Morbidity and mortality rates were similar for both groups. Anaesthetic duration > 2 h (vs. ≤ 2 h), pre-operative IL-6 level > 15 pg/ml (vs. ≤ 15 pg/ml) and post-operative IL-6 level 56-110 pg/ml (vs. ≤ 55 pg/ml) were independent predictors for post-operative infection. CONCLUSIONS: Intraoperative intensive glycaemic treatment significantly increased the risk of hypoglycaemia, but its effect on post-operative infection by clinical assessment could not be determined. Anaesthetic duration, pre-operative and post-operative IL-6 levels can independently predict post-operative infection.

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.

Strain-dependent differences for suppression of insulin-stimulated glucose uptake in skeletal and cardiac muscle by ethanol.

BACKGROUND: Chronic ethanol (EtOH) consumption impairs the ability of insulin to suppress hepatic glucose production in a strain-dependent manner, with hepatic insulin resistance being greater in Long-Evans (LE) than Sprague-Dawley (SD) rats. We assessed whether strain differences exist for whole-body and tissue glucose uptake under basal and insulin-stimulated conditions and whether they were associated with coordinate strain-dependent elevations in muscle cytokines. METHODS: Male rats (160 g) were provided the Lieber-DeCarli EtOH-containing (36% total energy) diet or pair-fed a control diet for 8 weeks. Rats were studied in the basal state or during a euglycemic hyperinsulinemic clamp, and whole-body glucose flux assessed using (3) H-glucose and in vivo tissue glucose uptake by (14) C-2-deoxyglucose. RESULTS: EtOH impaired whole-body insulin-mediated glucose uptake (IMGU) more in SD than LE rats. This difference was due to impaired IMGU by gastrocnemius and heart in EtOH-fed SD versus LE rats. However, decreased IMGU in adipose tissue (epididymal and perirenal) produced by EtOH was comparable between strains. EtOH-induced insulin resistance in muscle from SD rats was associated with reduced AKT and AS160 phosphorylation and plasma membrane-localized GLUT4 protein as well as enhanced phosphorylation of c-Jun N-terminal kinase (JNK) and IRS-1 (S307), changes which were absent in muscle from LE rats. EtOH increased tumor necrosis factor alpha (TNFα) mRNA in gastrocnemius and fat under basal conditions in both SD and LE rats; however, hyperinsulinemia decreased TNFα in skeletal muscle from LE, but not SD rats. Interleukin (IL)-6 mRNA in gastrocnemius was increased under basal conditions and increased further in response to insulin in SD rats, but no EtOH- or insulin-induced change was detected in muscle IL-6 of LE rats. CONCLUSIONS: These data indicate strain-dependent differences in EtOH-induced IMGU in skeletal and cardiac muscle, but not fat, associated with sustained increases in TNFα and IL-6 mRNA and JNK activation and decreased plasma membrane GLUT4 in response to insulin.

Serum fatty acid patterns, insulin sensitivity and the metabolic syndrome in individuals with chronic kidney disease.

OBJECTIVES: The causes of the multiple metabolic disorders of individuals with chronic kidney disease (CKD) are not fully known. We investigated the relationships between dietary fat quality, the metabolic syndrome (MetS), insulin sensitivity and inflammation in individuals with CKD. SUBJECTS: Two population-based surveys were conducted in elderly Swedish individuals (aged 70 years) with serum cystatin C-estimated glomerular filtration rate <60 mL min(-1) /1.73 m2: the Uppsala Longitudinal Study of Adult Men (ULSAM) and the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) surveys. The present population comprised 274 men and 187 subjects (63% women) from the ULSAM and PIVUS cohorts, respectively. DESIGN: Factor analyses of serum fatty acids were used to evaluate dietary fat quality. Insulin sensitivity was measured by homeostasis model assessment of insulin resistance (IR) and, in ULSAM, also by euglycaemic clamp. RESULTS: Factor analyses generated two fatty acid patterns of (i) low linoleic acid (LA)/high saturated fatty acid (SFA) or (ii) high n-3 polyunsaturated fatty acid (n-3 PUFA) levels. In both surveys, the low LA/high SFA pattern increased the odds of having MetS [adjusted odds ratio 0.60 [95% confidence interval (CI) 0.44-0.81] and 0.45 (95% CI 0.30-0.67) per SD decrease in factor score in the ULSAM and PIVUS surveys, respectively] and was directly associated with both IR and C-reactive protein. The n-3 PUFA pattern was not consistently associated with these risk factors. CONCLUSIONS: A serum fatty acid pattern reflecting low LA and high SFA was strongly associated with MetS, IR and inflammation in two independent surveys of elderly individuals with CKD. At present, there are no specific dietary guidelines for individuals with CKD; however, these findings indirectly support current recommendations to replace SFAs with PUFAs from vegetable oils.

Exaggerated release and preserved insulinotropic action of glucagon-like peptide-1 underlie insulin hypersecretion in glucose-tolerant individuals after Roux-en-Y gastric bypass.

AIMS/HYPOTHESIS: Roux-en-Y gastric bypass (RYGB) improves glycaemic control in part by increasing postprandial insulin secretion through exaggerated glucagon-like peptide (GLP)-1 release. However, it is unknown whether islet cell responsiveness to i.v. glucose, non-glucose (arginine) and incretin hormones, including GLP-1, is altered. METHODS: Eleven severely obese glucose-tolerant individuals underwent three hyperglycaemic clamps with arginine bolus and co-infusion of either GLP-1, glucose-dependent insulinotropic polypeptide (GIP) or saline before, and at 1 week and 3 months after RYGB. In addition, an OGTT was performed before and 3 months after surgery. RESULTS: After RYGB, insulin sensitivity improved at 1 week and 3 months, while insulin stimulation and glucagon suppression in response to the clamp with saline co-infusion were largely unaltered. The influence of i.v. GLP-1 and GIP on insulin and glucagon secretion was also unchanged postoperatively. In response to the postoperative OGTT at 3 months, insulin and GLP-1, but not GIP, secretion increased. Furthermore, the glucose profile during the OGTT was altered, with a substantial reduction in 2 h plasma glucose and a paradoxical hypersecretion of glucagon. CONCLUSIONS/INTERPRETATION: After RYGB, insulin hypersecretion is linked to the oral, but not the i.v., route of administration and is associated with exaggerated release and preserved insulinotropic action of GLP-1, while both the secretion and action of GIP are unchanged. The results highlight the importance of increased GLP-1 secretion for improving postoperative glucose metabolism. TRIAL REGISTRATION: ClinicalTrials.gov NCT01559779.

O envelhecimento do pâncreas endócrino: fisiopatologia de diabetes mellitus tipo 2 e a caracterização da incretinopatia com início na senectude / The aging of endocrine pancreas: physiopathology of diabetes mellitus type 2 and characterization of incretinpathy starting on senescence

Objetivo: Estimar o impacto do envelhecimento e do diabetes na sensibilidade à insulina, função da célula beta, adipocitocinas e produção de incretina Métodos: Foram realizados clamps hiperglicêmicos, testes de arginina e testes de refeição padrão em 50 pacientes não obesos para medir a sensibilidade à insulina e secreção de insulina, assim como os níveis plasmáticos do glucagon, GLP-1 e GIP. Os pacientes com diabetes e do grupo controle saudáveis foram divididos nos seguintes grupos: meia idade com diabetes tipo 2 (MI-DM2), idosos com diabetes tipo 2 (I-DM2), meia idade ou idosos com tolerância normal à glicose (MI-TNG, I-TNG). Resultados: A sensibilidade à insulina (SI), determinada pelo modelo de avaliação da homeostase, taxa de infusão de glicose e pela sensibilidade à insulina a glicose oral, foi reduzida no grupo de idosos e nos grupos com DM2, comparados com o grupo de meia idade com tolerância normal à glicose, mas foi similar no grupo MI-DM2 e grupo I-DM2. O índice insulinogênico, a primeira e segunda fase de secreção de insulina e o índice de disposição, com exceção da resposta da insulina à arginina, foram reduzidos com o envelhecimento e nos grupos com DM2. A produção pós-prandial média de glucagon no tempo total de 0 - 180 minutos foram maiores no grupo de DM2 comparado ao grupo de TNG, sendo que na primeira hora da produção de glugagon o grupo de I-DM2 apresentou uma média mais elevado em relação ao grupo de MI-DM2. Embora a produção de GLP-1 tenha sido reduzida no grupo I-DM2, nenhuma diferença entre os grupos foi observada em relação à produção de GIP. Conclusão: O diabetes e o envelhecimento desencadearam uma redução da sensibilidade à insulina em pacientes não obesos. A produção de insulina foi reduzida com o envelhecimento e exacerbada pela condição do diabetes. As deficiências associadas ao envelhecimento se sobrepõe a fisiopatologia do diabetes, particularmente relacionada à produção de GLP-1...

Objective: To estimate the impact of aging and diabetes on insulin sensitivity, beta-cell function, adipocytokines, and incretin production. Methods: Hyperglycemic clamps, arginine tests and meal tolerance tests were performed in 50 non-obese subjects to measure insulin sensitivity (IS) and insulin secretion as well as plasma levels of glucagon, GLP-1 and GIP. Patients with diabetes and healthy control subjects were divided into the following groups: middle-aged type 2 diabetes (MA-DM), elderly Type 2 diabetes (E-DM) and middle-aged or elderly subjects with normal glucose tolerance (MA-NGT or E-NGT). Results: IS (insulin sensitivity), as determined by the homeostasis model assessment glucose infusion rate and oral glucose insulin sensitivity, was reduced in the aged and DM groups compared with MA-NGT, but similar in MA-DM and E-DM groups. Insulinogenic index, first and second phase of insulin secretion and the disposition indices, except insulin response to arginine, were reduced in the elderly and DM groups. The average postprandial glucagon production on the interval of 0-180 min was higher in DM groups compared to NGT groups, furthermore noticed that in the first hour of glucagon secretion, group E-DM had a higher average value compared to group MA-DM. Whereas the GLP-1 production was reduced in A-DM, no differences between groups were observed in GIP production. Conclusions: In non-obese subjects, diabetes and aging impair insulin sensitivity. Insulin production is reduced by aging, and diabetes exacerbates this condition. Aging associated defects superimposed diabetic physiopathology, particularly regarding GLP-1 production. On the other hand, the glucose-independent secretion of insulin was preserved. The knowledge of the complex relationship between aging and diabetes could support the development of physiopathological and pharmacological based therapies.