Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

Influence of general anaesthesia on circulating biomarkers of glucose metabolism in pigs

Pigs are widely used in metabolic research with procedures often requiring general anaesthesia. The aim was to investigate the effect of four different anaesthetic protocols: 1) isoflurane inhalation, 2) propofol infusion, 3) a mixture of tiletamine, zolazepam, medetomidine, ketamine and butorphanol (TZMKB)) and 4) ketamine combined with midazolam and xylazine (KMX)) on selected biomarkers during basal and glucose stimulated conditions. Eight domestic pigs were included in a cross-over design. Plasma concentrations of glucose, insulin, C-peptide, glucagon, cortisol, triglycerides, total cholesterol, aspartate amino transferase and alanine amino transferase, creatinine, urea, fructosamine, albumin, free fatty acids (FFAs) and glycerol were measured at baseline, during 2 h of anaesthesia and during 1 h of recovery. Intravenous glucose tolerance test (IVGTT, 0.5 g glucose/kg) was performed after 1 h of anaesthesia. Glucose disappearance rate and areas under the insulin, C-peptide and glucagon curves from the IVGTT were calculated. All four anaesthetic protocols affected glucose metabolism parameters significantly compared with un-anaesthetised pigs, which was particularly evident during IVGTT and for TZMKB and KMX anaesthesia. Propofol additionally influenced the plasma concentrations of triglycerides, FFAs and glycerol significantly. The remaining circulating biomarkers were largely unaffected by anaesthesia. These data underline the importance of considering the anaesthetic protocol in porcine studies of circulating metabolic biomarkers.

Associations of Betatrophin/ANGPTL8 with Septic Dyslipidemia in Human Peritonitis: An Explorative Analysis

Sepsis is defined by life-threatening organ dysfunction mediated by the host’s response to infection. This can result in septic dyslipidemia, which is involved in the neutralization of pathogen-related lipids. Knowledge of the regulatory mechanisms of septic dyslipidemia is incomplete. The cytokine betatrophin/Angiopoietin-like protein 8 (ANGPTL8) plays a role in the regulation of triacylglyceride metabolism, though its function in septic dyslipidemia remains unknown. Sixty-six patients were enrolled in a cross-sectional study. Circulating concentrations and adipose tissue (AT) mRNA expression of betatrophin/ANGPTL8 were studied in patients suffering from peritoneal sepsis. Insulin-resistant individuals and subjects without metabolic derangement/systemic inflammation were enrolled as controls. All underwent open abdominal surgery. Circulating betatrophin/ANGPTL8 was analyzed by an enzyme-linked immunosorbent assay and AT mRNA expression levels were assessed by real-time PCR. Standard laboratory analyses including lipid electrophoresis were evaluated. Sepsis patients showed pronounced septic dyslipidemia (p < 0.05 for all major lipid classes). Despite comparable betatrophin/ANGPTL8 mRNA expression in AT (p = 0.24), we found significantly increased circulating betatrophin/ANGPTL8 with septic dyslipidemia (p = 0.009). Expression levels of betatrophin/ANGPTL8 in AT correlated with circulating concentrations in both control groups (r = 0.61; p = 0.008 and r = 0.43; p = 0.034), while this association was undetectable in sepsis. After stratification, betatrophin/ANGPTL8 remained associated with hypertriacylglyceridemia (p < 0.05).

Randomized Trial to Compare Plasma Glucose Trends in Patients Undergoing Surgery for Supratentorial Gliomas under Maintenance of Sevoflurane, Desflurane, and Propofol

Background

Anesthetic agents influence the glycemic response by affecting the neuroendocrine surgical response or directly modifying pancreatic insulin release. Due to chances of neuronal damage, intraoperative hyperglycemia and hypoglycemia both are detrimental for patients undergoing neurosurgeries. Inhalational (sevoflurane and desflurane) and intravenous (propofol) agents have been found to raise intraoperative glucose levels in nonneurological surgeries.

Aim

We aimed to compare the intraoperative glucose levels in supratentorial glioma surgeries under the maintenance of three anesthetic agents such as sevoflurane, desflurane, and propofol.

Materials and Methods

This randomized trial was conducted with 90 nondiabetic adults with supratentorial glioma. Thirty patients were allocated randomly to the three groups receiving sevoflurane, desflurane, and propofol. Baseline and hourly plasma glucose levels were recorded. Postoperatively, the time required to achieve an Aldrete score of 9 and complications were assessed.

Results

Baseline plasma glucose levels were 111.23 ± 11.67, 109.47 ± 19.75, and 111.7 ± 13.88 mg/dL (P = 0.84) in sevoflurance, desflurane, and propofol group, respectively. All of them showed an elevation of plasma glucose in relation to the time of surgery with variable trends. In the 4^th and 5^th h, the elevations in the inhalational groups (sevoflurane and desflurane) were significantly higher than the propofol group (P = 0.003 and 0.002, respectively). The time for achieving Aldrete's score of 9 was higher in the propofol group (P < 0.0001). No differences were observed in the duration of hospital stay or complications.

Conclusions

Maintenance of anesthesia in nondiabetic patients showed clinically modest rise of plasma glucose which is higher in patients under sevoflurane and desflurane than under propofol. However, the immediate recovery was faster with inhalational agents compared to propofol-based anesthesia.

Propofol Improved Glucose Tolerance Associated with Increased FGF-21 and GLP-1 Production in Male Sprague-Dawley Rats

Anesthetics, particularly volatile anesthetics, have been shown to impair glucose metabolism and cause hyperglycemia, closely linking them with mortality and morbidity as related to surgery. Beyond being an anesthetic used for general anesthesia and sedation, intravenous hypnotic propofol displays an effect on glucose metabolism. To extend the scope of propofol studies, its effects on glucose metabolism were evaluated in male Sprague-Dawley rats of various ages. Unlike chloral hydrate and isoflurane, propofol had little effect on basal glucose levels in rats at 2 months of age, although it did reduce chloral hydrate- and isoflurane-induced hyperglycemia. Propofol reduced postload glucose levels after either intraperitoneal or oral administration of glucose in both 7- and 12-month-old rats, but not those at 2 months of age. These improved effects regarding propofol on glucose metabolism were accompanied by an increase in insulin, fibroblast growth factor-21 (FGF-21), and glucagon-like peptide-1 (GLP-1) secretion. Additionally, an increase in hepatic FGF-21 expression, GLP-1 signaling, and FGF-21 signaling, along with a decrease in endoplasmic reticulum (ER) stress, were noted in propofol-treated rats at 7 months of age. Current findings imply that propofol may turn into insulin-sensitizing molecules during situations of existing insulin resistance, which involve FGF-21, GLP-1, and ER stress.

Recurrent Hyperkalemia During General Anesthesia in a Dog

Objective: To describe the development of recurrent hyperkalemia in a dog that underwent general anesthesia at two different hospitals within a month. The definitive underlying cause of the hyperkalemia remains unknown. Case summary: A 11 year-old male neutered Rottweiler underwent general anesthesia on two separate occasions at two different hospitals for ophthalmic surgery within a month and developed marked hyperkalemia on each occasion. The patient received similar drug protocols in both instances, including propofol, midazolam, non-depolarizing neuromuscular blocking agents, and isoflurane inhalant anesthetic. The patient showed ECG changes consistent with hyperkalemia during the first anesthetic event, but not the second. No underlying cause of hyperkalemia was definitively identified. The patient responded to standard therapy for hyperkalemia on both occasions and serum potassium levels returned to normal. The patient was discharged from the hospital without further complications and post-operative rechecks showed persistently normal serum potassium levels. New or unique information provided: Considering that there is a relationship between the development of severe hyperkalemia and propofol administration in human patients, it is possible that such a relationship exists in veterinary patients. However, numerous other diseases and medications can also lead to peri-operative hyperkalemia. Veterinary professionals should be aware that hyperkalemia can develop intra-operatively and remains be an important differential diagnosis in bradycardic patients under anesthesia that are not responding to traditional therapies.

Propofol inhibits stromatoxin-1-sensitive voltage-dependent K+ channels in pancreatic β-cells and enhances insulin secretion

Background

Proper glycemic control is an important goal of critical care medicine, including perioperative patient care that can influence patients’ prognosis. Insulin secretion from pancreatic β-cells is generally assumed to play a critical role in glycemic control in response to an elevated blood glucose concentration. Many animal and human studies have demonstrated that perioperative drugs, including volatile anesthetics, have an impact on glucose-stimulated insulin secretion (GSIS). However, the effects of the intravenous anesthetic propofol on glucose metabolism and insulin sensitivity are largely unknown at present.

Methods

The effect of propofol on insulin secretion under low glucose or high glucose was examined in mouse MIN6 cells, rat INS-1 cells, and mouse pancreatic β-cells/islets. Cellular oxygen or energy metabolism was measured by Extracellular Flux Analyzer. Expression of glucose transporter 2 (GLUT2), potassium channels, and insulin mRNA was assessed by qRT-PCR. Protein expression of voltage-dependent potassium channels (Kv2) was also assessed by immunoblot. Propofol’s effects on potassium channels including stromatoxin-1-sensitive Kv channels and cellular oxygen and energy metabolisms were also examined.

Results

We showed that propofol, at clinically relevant doses, facilitates insulin secretion under low glucose conditions and GSIS in MIN6, INS-1 cells, and pancreatic β-cells/islets. Propofol did not affect intracellular ATP or ADP concentrations and cellular oxygen or energy metabolism. The mRNA expression of GLUT2 and channels including the voltage-dependent calcium channels Cav1.2, Kir6.2, and SUR1 subunit of K_ATP, and Kv2 were not affected by glucose or propofol. Finally, we demonstrated that propofol specifically blocks Kv currents in β-cells, resulting in insulin secretion in the presence of glucose.

Conclusions

Our data support the hypothesis that glucose induces membrane depolarization at the distal site, leading to K_ATP channel closure, and that the closure of Kv channels by propofol depolarization in β-cells enhances Ca²⁺ entry, leading to insulin secretion. Because its activity is dependent on GSIS, propofol and its derivatives are potential compounds that enhance and initiate β-cell electrical activity.

PTEN in propofol-induced insulin resistance in mouse primary hepatocytes

Propofol is the most common intravenous anesthetic agent used in clinical practice. Propofol can induce insulin resistance in mouse primary hepatocytes, however the molecular mechanism through which propofol acts remains largely unknown. Based on previous studies, it was hypothesized that phosphatase and tensin homolog (PTEN) is involved in propofol-mediated insulin resistance. The aim of the present study was to investigate the biological function of PTEN and its molecular mechanism in propofol-induced insulin resistance in mouse primary hepatocytes. Mouse primary hepatocytes were treated with propofol and transfected with small interfering RNA (siRNA)-996 to silence the endogenous expression of PTEN. The current study assessed the effects of propofol and PTEN knockdown on the expression of PTEN and several key enzymes of the phosphoinositide 3-kinase/protein kinase B/glycogen synthase kinase-3β signaling pathway, as well as the glycogen content in mouse primary hepatocytes. Treatment with propofol significantly increased protein and mRNA PTEN expression in mouse primary hepatocytes. In addition, knockdown of PTEN reversed propofol-induced insulin resistance in mouse primary hepatocytes. The present study indicated that PTEN serves a role in the physiological process of propofol-induced insulin resistance in mouse primary hepatocytes, and PTEN inhibition may be a potential target for therapeutic intervention against propofol-induced adverse effects.

Hyperpolarized [1-13 C]pyruvate MRI can image the metabolic shift in cardiac metabolism between the fasted and fed state in a porcine model

PURPOSE

Owing to its noninvasive nature, hyperpolarized MRI may improve delineation of myocardial metabolic derangement in heart disease. However, consistency may depend on the changeable nature of cardiac metabolism in relation to whole-body metabolic state. This study investigates the impact of feeding status on cardiac hyperpolarized MRI in a large animal model resembling human physiology.

METHODS

Thirteen 30-kg pigs were subjected to an overnight fast, and 5 pigs were fed a carbohydrate-rich meal on the morning of the experiments. Vital parameters and blood samples were registered. All pigs were then scanned by hyperpolarized [1-¹³ C]pyruvate cardiac MRI, and results were compared between the 2 groups and correlated with circulating substrates and hormones.

RESULTS

The fed group had higher blood glucose concentration and mean arterial pressure than the fasted group. Plasma concentrations of free fatty acids (FFAs) were decreased in the fed group, whereas plasma insulin concentrations were similar between groups. Hyperpolarized MRI showed that fed animals had increased lactate/pyruvate, alanine/pyruvate, and bicarbonate/pyruvate ratios. Metabolic ratios correlated negatively with FFA levels.

CONCLUSION

Hyperpolarized MR can identify the effects of different metabolic states on cardiac metabolism in a large animal model. Unlike previous rodent studies, all metabolic derivatives of pyruvate increased in the myocardium of fed pigs. Carbohydrate-rich feeding seems to be a feasible model for standardized, large animal hyperpolarized MRI studies of myocardial carbohydrate metabolism.

Role of Gated Myocardial Glucose Metabolic Imaging in Assessing Left Ventricular Systolic Dyssynchrony after Myocardial Infarction and the Influential Factors

In this study, we investigated the role of gated myocardial glucose metabolic imaging in assessing left ventricular (LV) systolic dyssynchrony after myocardial infarction (MI) and explored the influencing factors. Bama mini-pigs were divided into normal group and MI group and subjected to gated myocardial metabolic imaging (GMMI) and gated myocardial perfusion imaging (GMPI). The phase bandwidth (BW), standard deviation (SD) and the latest activation site of left ventricle were obtained using program Cedars QGS. The results showed that (1) BW and SD obtained in GMMI and GMPI showed significant correlation in pigs with MI, but not in the normal pigs, (2) BW and SD obtained in GMMI and GMPI had good consistency in both normal pigs and MI pigs, (3) GMMI and GMPI had a 66.7% identity in determining the latest activation site of left ventricle in the normal pigs and 77.8% identity in determining the latest activation site of left ventricle in pigs with MI. Multivariate stepwise regression analysis showed that total perfusion deficit and summed motion score were independent factors affecting BW and SD in GMMI. In conclusion, phase analysis of GMMI images could objectively reflect LV systolic dyssynchrony resulted from interactions of multiple factors.

Comparison of sevoflurane and propofol anesthesia on the incidence of hyperglycemia in patients with type 2 diabetes undergoing lung surgery

Background

The type and regimen of anesthesia may affect perioperative hyperglycemia following major surgical stress. This study compared the effects of sevoflurane and propofol on the incidence of hyperglycemia and clinical outcomes in diabetic patients undergoing lung surgery.

Methods

This retrospective study included 176 patients with type 2 diabetes mellitus who had undergone lung surgery. Blood glucose levels and clinical outcomes from the preoperative period to the first 2 post-operative days (PODs) were retrospectively examined in patients who received sevoflurane (group S, n= 87) and propofol (group P, n=89) for maintenance of general anesthesia. The primary endpoint was the incidence of persistent hyperglycemia (2 consecutive blood glucose levels >180 mg/dL [10.0 mmol/L]) during the perioperative period. The secondary composite endpoint was the incidence of major postoperative complications and 30-day mortality rate after surgery.

Results

Blood glucose levels similarly increased from the preoperative period to the second POD in both groups (p=0.857). Although blood glucose levels at 2 hours after surgery were significantly lower in group P than in group S (p=0.022; 95% confidence interval for mean difference, -27.154 to -2.090), there was no difference in the incidence of persistent hyperglycemia during the perioperative period (group S, 70%; group P, 69%; p=0.816). The composite of major postoperative complications and all-cause in-hospital and 30-day mortality rates were also comparable between the two groups.

Conclusion

Sevoflurane and propofol were associated with a comparable incidence of perioperative hyperglycemia and clinical outcomes in diabetic patients undergoing lung surgery.

Imaging porcine cardiac substrate selection modulations by glucose, insulin and potassium intervention: A hyperpolarized [1-13 C]pyruvate study

Cardiac metabolism has received considerable attention in terms of both diagnostics and prognostics, as well as a novel target for treatment. As human trials involving hyperpolarized magnetic resonance in the heart are imminent, we sought to evaluate the general feasibility of detection of an imposed shift in metabolic substrate utilization during metabolic modulation with glucose-insulin-potassium (GIK) infusion, and thus the limitations associated with this strategy, in a large animal model resembling human physiology. Four [1-¹³ C]pyruvate injections did not alter the blood pressure or ejection fraction over 180 min. Hyperpolarized [1-¹³ C]pyruvate conversion showed a generally high reproducibility, with intraclass correlation coefficients between the baseline measurements at 0 and 30 min as follows: lactate to pyruvate, 0.85; alanine to pyruvate, 1.00; bicarbonate to pyruvate, 0.83. This study demonstrates that hyperpolarized [1-¹³ C]pyruvate imaging is a feasible technique for cardiac studies and shows a generally high reproducibility in fasted large animals. GIK infusion increases the metabolic conversion of pyruvate to its metabolic derivatives lactate, alanine and bicarbonate, but with increased variability.

Isoflurane and Sevoflurane Induce Severe Hepatic Insulin Resistance in a Canine Model

Introduction

Anesthesia induces insulin resistance, which may contribute to elevated blood glucose and adverse post-operative outcomes in critically ill patients, and impair glycemic control in surgical patients with diabetes. However, little is known about the mechanisms by which anesthesia impairs insulin sensitivity. Here we investigate the effects of anesthesia on insulin sensitivity in metabolic tissues.

Methods

Hyperinsulinemic-euglycemic clamps were performed in 32 lean (control diet; n = 16 conscious versus n = 16 anesthetized) and 24 fat-fed (6 weeks fat-feeding; n = 16 conscious versus n = 8 anesthetized) adult male mongrel dogs in conjunction with tracer methodology to differentiate hepatic versus peripheral insulin sensitivity. Propofol was administered as an intravenous bolus (3mg/kg) to initiate anesthesia, which was then maintained with inhaled sevoflurane or isoflurane (2–3%) for the duration of the procedure.

Results

Anesthesia reduced peripheral insulin sensitivity by approximately 50% in both lean and fat-fed animals as compared to conscious animals, and insulin action at the liver was almost completely suppressed during anesthesia such that hepatic insulin sensitivity was decreased by 75.5% and; 116.2% in lean and fat-fed groups, respectively.

Conclusion

Inhaled anesthesia induces severe hepatic insulin resistance in a canine model. Countermeasures that preserve hepatic insulin sensitivity may represent a therapeutic target that could improve surgical outcomes in both diabetic and healthy patients.

Protective effect of pretreatment with propofol against tumor necrosis factor-α-induced hepatic insulin resistance

Insulin resistance is common in critically ill patients and seriously affects their prognosis. The anesthetic propofol (2,6-diisopropylphenol) has been shown to cause insulin resistance in rats; however, the specific mechanism underlying this phenomenon remains unknown. Thus, the aim of the present study was to determine the molecular mechanism through which propofol influences insulin resistance in the liver. The current study assessed the effects of propofol on the phosphorylation level of key enzymes involved in the insulin signaling pathway, as well as the glycogen content in primary mouse hepatocytes. Propofol administration was demonstrated to considerably reduce the phosphorylation levels of Akt (Ser473) and glycogen synthase kinase (GSK)-3β (Ser9) in the primary mouse hepatocytes. In addition, propofol was shown to downregulate the phosphoinositide 3-kinase (PI3K)/Akt/GSK-3β signaling pathway and inhibit glycogen synthesis in hepatocytes. Thus, the present results indicated that propofol induced insulin resistance in primary mouse hepatocytes. Notably, pretreatment with propofol in tumor necrosis factor (TNF)-α-induced primary mouse hepatocytes with insulin resistance was demonstrated to alleviate the inhibitory effects of TNF-α on the PI3K/Akt/GSK-3β signaling pathway and glycogen synthesis. These results indicated that propofol exerts a protective effect against insulin resistance in primary mouse hepatocytes induced by TNF-α, indicating that propofol therapy may be clinically feasible to alleviate insulin resistance in critically ill patients.

The Effects of Propofol and Isoflurane on Blood Glucose during Abdominal Hysterectomy in Diabetic Patients

BACKGROUND

Acute hyperglycemia in the perioperative period is associated with significantly increased complications. In few human studies the effects of propofol and inhalational anesthetic on the glucose metabolism were compared. In this study we evaluated the effect of propofol and isoflurane on blood glucose during abdominal hysterectomy in diabetic patients.

METHODS

After approval by the Ethical Committee and written informed consent, thirty 35 to 65 years old diabetic women underwent for elective abdominal hysterectomy under general anesthesia were studied in this randomized single blind clinical trial study. The plasma glucose was maintained at 100 to 180 mg/dL during the operation. Anesthesia protocol was similar in two groups except maintenance of anesthesia that was with infusion of propofol in the propofol group and with isoflurane in the isoflurane group. Blood glucose level and the rate of insulin intake during surgery compared between two groups.

RESULTS

Mean blood glucose before induction of anesthesia did not have significant difference between two groups, but 60 and 90 minutes after starting the operation blood glucose in the propofol group was significantly lower than isoflurane group. Also with using Repeated Measure test, two groups was significantly different according to blood glucose (P=0.045). Mean of administration of insulin during the surgery did not have significant difference between two groups by using repeated measure test and P=0.271. Also mean of bispectral index in different times during the surgery between two groups didn't have significant difference (P=0.35 repeated measure test).

CONCLUSION

Blood glucose increased during maintenance of anesthesia with isoflurane compared to propofol during the surgery.