Is insulin an antiinflammatory molecule?

Identifying TNF and IL6 as potential hub genes and targeted drugs associated with scleritis: A bio-informative report

Background

Scleritis is a serious inflammatory eye disease that can lead to blindness. The etiology and pathogenesis of scleritis remain unclear, and increasing evidence indicates that some specific genes and proteins are involved. This study aimed to identify pivotal genes and drug targets for scleritis, thus providing new directions for the treatment of this disease.

Methods

We screened candidate genes and proteins associated with scleritis by text-mining the PubMed database using Python, and assessed their functions by using the DAVID database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to identify the functional enrichment of these genes and proteins. Then, the hub genes were identified with CytoHubba and assessed by protein-protein interaction (PPI) network analysis. And the serum from patients with active scleritis and healthy subjects were used for the validation of hub genes. Finally, the DGIdb database was used to predict targeted drugs for the hub genes for treating scleritis.

Results

A total of 56 genes and proteins were found to be linked to scleritis, and 65 significantly altered pathways were identified in the KEGG analysis (FDR < 0.05). Most of the top five pathways involved the categories “Rheumatoid arthritis,” “Inflammatory bowel disease”, “Type I diabetes mellitus,” and “Graft-versus-host disease”. TNF and IL6 were considered to be the top 2 hub genes through CytoHubba. Based on our serum samples, hub genes are expressed at high levels in active scleritis. Five scleritis-targeting drugs were found among 88 identified drugs.

Conclusions

This study provides key genes and drug targets related to scleritis through bioinformatics analysis. TNF and IL6 are considered key mediators and possible drug targets of scleritis. Five drug candidates may play an important role in the diagnosis and treatment of scleritis in the future, which is worthy of the further experimental and clinical study.

Essential Fatty Acids and Their Metabolites in the Pathobiology of Inflammation and Its Resolution

Arachidonic acid (AA) metabolism is critical in the initiation and resolution of inflammation. Prostaglandin E2 (PGE2) and leukotriene B4/D4/E4 (LTB4/LD4/LTE4), derived from AA, are involved in the initiation of inflammation and regulation of immune response, hematopoiesis, and M1 (pro-inflammatory) macrophage facilitation. Paradoxically, PGE2 suppresses interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) production and triggers the production of lipoxin A4 (LXA4) from AA to initiate inflammation resolution process and augment regeneration of tissues. LXA4 suppresses PGE2 and LTs' synthesis and action and facilitates M2 macrophage generation to resolve inflammation. AA inactivates enveloped viruses including SARS-CoV-2. Macrophages, NK cells, T cells, and other immunocytes release AA and other bioactive lipids to produce their anti-microbial actions. AA, PGE2, and LXA4 have cytoprotective actions, regulate nitric oxide generation, and are critical to maintain cell shape and control cell motility and phagocytosis, and inflammation, immunity, and anti-microbial actions. Hence, it is proposed that AA plays a crucial role in the pathobiology of ischemia/reperfusion injury, sepsis, COVID-19, and other critical illnesses, implying that its (AA) administration may be of significant benefit in the prevention and amelioration of these diseases.

A New Prognostic Index PDPI for the Risk of Pneumonia Among Patients With Diabetes

Objective

Risk factors for the development of pneumonia among patients with diabetes mellitus are unclear. The aim of our study was to elucidate the potential risk factors and attempt to predict the probability of pneumonia based on the history of diabetes.

Methods

We performed a population-based, prospective multicenter cohort study of 1,043 adult patients with diabetes in China during 2017–2019. Demographic information, comorbidities, or laboratory examinations were collected.

Results

The study included 417 diabetic patients with pneumonia and 626 no-pneumonia-onset diabetic patients. The predictive risk factors were chosen on the basis of a multivariate logistic regression model to predict pneumonia among patients with diabetes including male sex [odds ratio (OR) = 1.72, 95% confidence interval (CI): 1.27–2.33, p < 0.001], age ≥ 75 years (OR = 2.31, 95% CI: 1.61–3.31, p < 0.001), body mass index < 25 (OR = 2.59, 95% CI: 1.92–3.50, p < 0.001), chronic obstructive pulmonary disease (OR = 6.58, 95% CI: 2.09–20.7, p = 0.001), hypertension (OR = 4.27, 95% CI: 3.12–5.85, p < 0.001), coronary heart disease (OR = 2.98, 95% CI: 1.61–5.52, p < 0.001), renal failure (OR = 1.82, 95% CI: 1.002–3.29, p = 0.049), cancer (OR = 3.57, 95% CI: 1.80–7.06, p < 0.001), use of insulin (OR = 2.28, 95% CI: 1.60–3.25, p < 0.001), and hemoglobin A1c ≥ 9% (OR = 2.70, 95% CI: 1.89–3.85, p < 0.001). A predictive nomogram was established. This model showed c-statistics of 0.811, and sensitivity and specificity were 0.717 and 0.780, respectively, under cut-off of 125 score.

Conclusion

We designed a clinically predictive tool for assessing the risk of pneumonia among adult patients with diabetes. This tool stratifies patients into relevant risk categories and may provide a basis for individually tailored intervention for the purpose of early prevention.

Metabolic Syndrome and Parkinson's Disease Incidence: A Nationwide Study Using Propensity Score Matching

Background: Metabolic syndrome (MetS) and Parkinson's disease (PD) share common pathophysiological mechanisms. This study aimed to investigate the influence of MetS on PD incidence. Materials and Methods: A propensity score-matched cohort study was conducted using the National Health Insurance Service-National Health Screening Cohort (NHIS-HealS) data (2002-2015) from the Korean National Health Insurance Service. Individuals with MetS were identified from those who underwent a health checkup in 2009-2010 and were 1:1 matched to individuals without MetS (non-MetS) using the propensity score method. Among 314,737 eligible individuals, 85,530 MetS and non-MetS pairs were selected. Results: During a mean follow-up of 7.23 years, 819 (0.48%) PD cases occurred. Individuals with MetS exhibited 1.23 times greater PD incidence (95% confidence interval [CI], 1.06-1.43; P = 0.006). The risk of PD increased with the number of MetS components, with the presence of five MetS components altogether doubling the incidence of PD (odds ratio [OR], 2.00; 95% CI, 1.30-3.04; P = 0.001). High blood pressure, low high-density lipoprotein cholesterol, and high fasting blood glucose increased PD incidence by 1.34 times (95% CI, 1.15-1.58; P < 0.001), 1.31 times (95% CI, 1.13-1.52; P < 0.001), and 1.20 times (95% CI, 1.04-1.38; P = 0.013), respectively. Elevated waist circumference was not associated with PD incidence (OR, 1.11; 95% CI, 0.96-1.28; P = 0.176). High triglycerides exerted a protective effect against PD incidence especially in men (OR, 0.66; 95% CI, 0.54-0.81; P < 0.001). Conclusions: MetS may be a risk factor for PD incidence, and individual components of MetS exert different effects depending on sex.

Nutritional intervention as an essential part of multiple sclerosis treatment?

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system. In addition to the genetic, epigenetic and immunological components, various other factors, e.g. unhealthy dietary habits, play a role in the MS pathogenesis. Dietary intervention is a highly appealing approach, as it presents a simple and relatively low risk method to potentially improve outcomes in patients with brain disorders in order to achieve remission and improvement of clinical status, well-being and life expectancy of patients with MS. The importance of saturated fat intake restriction for the clinical status improvement of MS patients was pointed for the first time in 1950s. Recently, decreased risk of first clinical diagnosis of CNS demyelination associated with higher intake of omega-3 polyunsaturated fatty acids particularly originating from fish was reported. Only few clinical trials have been performed to address the question of the role of dietary intervention, such is e.g. low saturated fat diet in MS treatment. This review summarizes current knowledge about the effect of different dietary approaches (diets low in saturated fat and dietary supplements such as fish oil, lipoic acid, omega-3 polyunsaturated fatty acids, seeds oils, high fiber diet, vitamin D, etc.) on neurological signs, patient's well-being, physical and inflammatory status. So far the results are not conclusive, therefore much more research is needed to confirm and to understand the effectiveness of these dietary interventions in the long term and well defined studies.

Ageing: Is there a role for arachidonic acid and other bioactive lipids? A review

Ageing is inevitable. Recent studies suggest that it could be delayed. Low-grade systemic inflammation is seen in type 2 diabetes mellitus, hypertension and endothelial dysfunction that are common with increasing age. In all these conditions, an alteration in arachidonic acid (AA) metabolism is seen in the form of increased formation of pro-inflammatory eicosanoids and decreased production of anti-inflammatory lipoxins, resolvins, protectins and maresins and decreased activity of desaturases. Calorie restriction, exercise and parabiosis delay age-related changes that could be related to enhanced proliferation of stem cells, decrease in inflammation and transfer of GDF-11 (growth differentiation factor-11) and other related molecules from the young to the old, increase in the formation of lipoxin A4, resolvins, protectins and maresins, hydrogen sulfide (H2S) and nitric oxide (NO); inhibition of ageing-related hypothalamic or brain IKK-β and NF-kB activation, decreased gonadotropin-releasing hormone (GnRH) release resulting in increased neurogenesis and consequent decelerated ageing. This suggests that hypothalamus participates in ageing process. N-acylethanolamines (NAEs) and lipid-derived signalling molecules can be tuned favorably under dietary restriction to extend lifespan and/or prevent advanced age associated diseases in an mTOR dependent pathway manner. Sulfur amino acid (SAA) restriction increased hydrogen sulfide (H2S) production and protected tissues from hypoxia and tissue damage. Anti-inflammatory metabolites formed from AA such as LXA4, resolvins, protectins and maresins enhance production of NO, CO, H2S; suppress NF-kB expression and alter mTOR expression and thus, may aid in delaying ageing process. Dietary restriction and exercise enhance AA metabolism to form LXA4, resolvins, protectins and maresins that have anti-inflammatory actions. AA and their metabolites also influence stem cell biology, enhance neurogenesis to improve memory and augment autophagy to prolong life span. Thus, AA and other PUFAs and their anti-inflammatory metabolites inhibit inflammation, augment stem cell proliferation, restore to normal lipid-derived signaling molecules and NO and H2S production, enhance autophagy and prolong life span.

Potential mechanism and drug candidates for sepsis-induced acute lung injury

The present study aimed to explore the mechanisms underlying sepsis-induced acute lung injury (ALI) and identify more effective therapeutic strategies to treat it. The gene expression data set GSE10474 was downloaded and assessed to identify differentially expressed genes (DEGs). Principal component analysis, functional enrichment analysis and differential co-expression analysis of DEGs were performed. Furthermore, potential target drugs for key DEGs were assessed. A total of 209 DEGs, including 107 upregulated and 102 downregulated genes were screened. A number of DEGs, including zinc finger and BTB domain containing 17 (ZBTB17), heat shock protein 90 kDa β, member 1 (HSP90B1) and major histocompatibility complex, class II, DR α were identified. Furthermore, gene ontology terms including antigen processing and presentation, glycerophospholipid metabolism, transcriptional misregulation in cancer, thyroid hormone synthesis and pathways associated with diseases, such as asthma were identified. In addition, a differential co-expression network containing ubiquitin-conjugating enzyme E2 D4, putative and tubulin, γ complex associated protein 3 was constructed. Furthermore, a number of gene-drug interactions, including between HSP90B1 and adenosine-5′-diphosphate and radicicol, were identified. Therefore, DEGs, including ZBTB17 and HSP90B1, may be important in the pathogenesis of sepsis-induced ALI. Furthermore, drugs including adenosine-5′-diphosphate may be novel drug candidates to treat patients with ALI.

Blood Lactate Levels Cutoff and Mortality Prediction in Sepsis-Time for a Reappraisal? a Retrospective Cohort Study

The objective of this study was to identify the initial value of blood lactate that best correlates with 28-day mortality in resuscitated septic shock patients. This was a retrospective cohort study including 443 patients admitted to an intensive care unit (ICU) with severe sepsis or septic shock from the emergency department. A receiver-operating characteristic (ROC) curve was drawn to obtain the best cutoff value for initial blood lactate associated with 28-day mortality. Patients were then dichotomized according to the chosen lactate cutoff, and sensitivity, specificity, and positive and negative predictive values were calculated. Baseline blood lactate level more than 2.5 mmol/L showed the largest area under the ROC curve to predict 28-day mortality (ROC area, 0.70; 95% confidence interval [CI], 0.62-0.79), with sensitivity, specificity, and negative predictive value of 67.4%, 61.7%, and 94.2%, respectively. Mortality at 28 days was 16.9% (31/183) in patients with initial lactate more than 2.5 mmol/L and 5.8% (15/260) in patients with initial lactate at most 2.5 mmol/L (relative risk, 2.93; 95% CI, 1.63-5.28; P < 0.001). Initial blood lactate levels more than 2.5 mmol/L (hazard ratio [HR], 2.86; 95% CI, 1.53-5.33; P = 0.001) and Sepsis-related Organ Failure Assessment score at ICU admission (HR, 1.18; 95% CI, 1.09-1.27; P < 0.001) were associated with increased 28-day mortality in the adjusted Cox regression. In this retrospective cohort study, a lactate level more than 2.5 mmol/L was the best threshold to predict 28-day mortality among severe sepsis and septic shock patients. Further prospective studies should address the impact on morbidity and mortality of this threshold as a trigger to resuscitation in this population of critically ill patients.

Is There a Role for Bioactive Lipids in the Pathobiology of Diabetes Mellitus?

Inflammation, decreased levels of circulating endothelial nitric oxide (eNO) and brain-derived neurotrophic factor (BDNF), altered activity of hypothalamic neurotransmitters (including serotonin and vagal tone) and gut hormones, increased concentrations of free radicals, and imbalance in the levels of bioactive lipids and their pro- and anti-inflammatory metabolites have been suggested to play a role in diabetes mellitus (DM). Type 1 diabetes mellitus (type 1 DM) is due to autoimmune destruction of pancreatic β cells because of enhanced production of IL-6 and tumor necrosis factor-α (TNF-α) and other pro-inflammatory cytokines released by immunocytes infiltrating the pancreas in response to unknown exogenous and endogenous toxin(s). On the other hand, type 2 DM is due to increased peripheral insulin resistance secondary to enhanced production of IL-6 and TNF-α in response to high-fat and/or calorie-rich diet (rich in saturated and trans fats). Type 2 DM is also associated with significant alterations in the production and action of hypothalamic neurotransmitters, eNO, BDNF, free radicals, gut hormones, and vagus nerve activity. Thus, type 1 DM is because of excess production of pro-inflammatory cytokines close to β cells, whereas type 2 DM is due to excess of pro-inflammatory cytokines in the systemic circulation. Hence, methods designed to suppress excess production of pro-inflammatory cytokines may form a new approach to prevent both type 1 and type 2 DM. Roux-en-Y gastric bypass and similar surgeries ameliorate type 2 DM, partly by restoring to normal: gut hormones, hypothalamic neurotransmitters, eNO, vagal activity, gut microbiota, bioactive lipids, BDNF production in the gut and hypothalamus, concentrations of cytokines and free radicals that results in resetting glucose-stimulated insulin production by pancreatic β cells. Our recent studies suggested that bioactive lipids, such as arachidonic acid, eicosapentaneoic acid, and docosahexaenoic acid (which are unsaturated fatty acids) and their anti-inflammatory metabolites: lipoxin A4, resolvins, protectins, and maresins, may have antidiabetic actions. These bioactive lipids have anti-inflammatory actions, enhance eNO, BDNF production, restore hypothalamic dysfunction, enhance vagal tone, modulate production and action of ghrelin, leptin and adiponectin, and influence gut microbiota that may explain their antidiabetic action. These pieces of evidence suggest that methods designed to selectively deliver bioactive lipids to pancreatic β cells, gut, liver, and muscle may prevent type 1 and type 2 DM.

Sustained delivery of insulin-loaded block copolymers: Potential implications on renal ischemia/reperfusion injury in diabetes mellitus

The purpose of this research was to evaluate the protective effects of insulin-loaded poly(ethylene glycol)-b-poly((2-aminoethyl-l-glutamate)-g-poly(l-lysine)) (PEG-b-P(ELG-g-PLL)) on renal ischemia/reperfusion (I/R) injury in rats with diabetes mellitus. Rats were preconditioned with free insulin or insulin/PEG-b-P(ELG-g-PLL) polyplexes, then subjected to renal I/R. The blood and kidneys were then harvested, Glucose uptake rate, glucose transporter 4 (GULT4) mRNA level, cell membrane GULT4 content and GULT4 expression were measured, the level of serum creatinine and blood urea nitrogen were determined, the activity of superoxide dismutase and inducible nitric oxide synthase, the content of malondialdehyde and nitric oxide, reactive oxygen species (ROS) production and nuclear factor κB (NF-κB) mRNA level, Bcl-2 assaciated x protein (Bax) mRNA and B cell lymphoma/lewkmia-2 (Bcl-2) mRNA level, and the expression of protein 47kDa phagocyte oxidase (p47phox) in renal tissues were measured. Insulin preconditioning improved the recovery of renal function, reduced oxidative stress injury, restored nitroso-redox balance and downregulated the expression of p47phox induced by renal I/R injury, while the application of block copolymer PEG-b-P(ELG-g-PLL) as an insulin nanocarrier significantly enhanced the protective effect of insulin. Block copolymer PEG-b-P(ELG-g-PLL) could be used as a potential nanocarrier for insulin with sustained release and enhanced bioavailability.

Glycemia Influences on Glucose Metabolism in Sepsis During Hyperinsulinemic Clamp

BACKGROUND

We investigated glucose metabolism in septic patients during hyperglycemic clamps and compared the different levels of insulinemia and glycemia.

METHODS

In 10 non-diabetic stable septic patients on mechanical ventilation with baseline glycemia >6 mmol/L and continuous insulin infusion, 3 steps of hyperinsulinemic clamp were performed after 8 hours without caloric intake. In step 1, the targets were insulinemia of 250 mIU/L and glycemia of 5 mmol/L; in step 2, insulinemia of 250 mIU/L and glycemia of 10 mmol/L; in step 3, insulinemia of 1250 mIU/L and glycemia of 5 mmol/L. Glucose uptake was calculated as the amount of glucose per time needed to maintain the target level of glycemia. Glucose oxidation was calculated from indirect calorimetry and urinary nitrogen losses. Values are provided as means +/- SD. A two-way analysis of variance and Scheffe's method were used for statistical analysis and p < .05 was considered significant.

RESULTS

At step 1, glucose uptake was lower than at step 2 (3.8 +/- 2.48 mg/kg/min and 7.9 +/- 3.45 mg/kg/min, respectively; p < .001). Glucose oxidation was also lower at step 1 (2.6 +/- 0.98 and 4.2 +/- 1.85 mg/kg/min, respectively; p < .01). Glucose storage was low at step 1 (0.7 +/- 1.39) and increased at step 2 (3.5 +/- 2.18; p < .05). In step 3, glucose uptake was 7.0 +/- 2.1, oxidation was 3.6 +/- 1.37, and storage was 2.9 +/- 2.79. There was no significant difference in all these parameters between steps 2 and 3. Energy expenditure between steps 1, 2 and 3 did not change (2294 + 307.42, 2334 + 341.53, and 2342 + 426.67 kcal/day, respectively). Alanine in plasma dropped significantly (p < .05): 10 mmol/L (311 +/- 55.88 mmol/L) at glycemia compared with 5 mmol/L (390 +/- 76 micromol/L) at insulinemia 250 mIU/L. It did not differ significantly from the values obtained at glycemia 5 mmol/L and insulinemia 1250 mIU/L (348 +/- 70.68 mmol/L). Even if the level of cytokines in sepsis was higher, there was no correlation between the insulin level in plasma (250 and 1250 mIU/L), glycemia (5 and 10 mmol/L) and cytokine level (IL-1beta, IL-2, IL-6, IL-8 and TNFalpha).

CONCLUSION

At insulinemia 250 mIU/L, a glucose level of 10 mmol/L seems to increase glucose uptake, oxidation, and storage compared with glycemia 5 mmol/L. This glucose uptake and oxidation at glycemia 10 mmol/L is comparable with the effect of extremely high insulinemia (1250 mIU/L) clamped at glycemia 5 mmol/L. A higher level of blood glucose or a high level of insulinemia significantly increases glucose uptake but not energy expenditure.

Glucose-insulin-potassium correlates with hemodynamic improvement in patients with septic myocardial dysfunction

BACKGROUND

Glucose-insulin-potassium (GIK) demonstrates a cardioprotective effect by providing metabolic support and anti-inflammatory action, and may be useful in septic myocardial depression. The aim of this study was to examine the relationship between GIK and hemodynamic outcomes in septic shock patients with myocardial depression.

METHODS

Between October 2012 and March 2014, 45 patients in the intensive care unit who fulfilled the criteria for severe sepsis/septic shock and were treated with GIK were recruited. Patients were divided into two groups according to echocardiographic findings: hypodynamic (27%) and non-hypodynamic (36%).

RESULTS

Baseline vasopressor requirements did not differ between both groups. In 12 patients with hypodynamic septic shock with myocardial depression, mean arterial pressure (MAP) increased with the median [interquartile range (IQR)] area under the curve of 16 (8 to 29) mmHg, and the heart rate (HR) decreased with the median (IQR) area under the curve of -9 (-20 to 2)/min during the first 72 h. The total insulin dose correlated with improvement in MAP (r=0.61, P=0.061) and the cardiovascular Sequential Organ Failure Assessment score (r=-0.64, P=0.045) at 72 h, although this phenomenon was not observed in patients with non-hypodynamic septic shock. Serum glucose and potassium levels were within the target ranges in both groups during the 72-h study period.

CONCLUSIONS

Short-term improvement in hemodynamics correlated with GIK administration in septic shock patients with myocardial depression. The use of GIK was well tolerated in all patients. Further studies are required to demonstrate the role of GIK in septic myocardial dysfunction.

Combination of aspirin with essential fatty acids is superior to aspirin alone to prevent or ameliorate sepsis or ARDS

It has been suggested that aspirin may be of benefit in treating sepsis and ARDS in view of its ability to block cyclo-oxygenase-1 (COX-1) and COX-2 activities; inhibit nuclear factor kappa B (NF-κB); enhance the production of endothelial nitric oxide (eNO) and lipoxin A4 (LXA4). Our previous studies revealed that plasma phospholipid content of arachidonic acid (AA) and eicosapentaenoic acid (EPA) is low in patients with sepsis. This implies that beneficial actions of aspirin in sepsis and ARDS is unlikely to be obtained in view of deficiency of AA and EPA, the precursors of LXA4 and resolvins respectively that are potent anti-inflammatory compounds and enhancers of eNO generation. In view of this, I propose that a combination of aspirin and AA and EPA (and possibly, docosahexaenoic acid, DHA) is likely to be superior in the management of sepsis and ARDS compared to aspirin alone. This suggestion is supported by the recent observation that trauma patients with uncomplicated recoveries had higher resolvin pathway gene expression and lower gene expression ratios of leukotriene: resolvin pathways.

Effects of intensive insulin therapy combined with low molecular weight heparin anticoagulant therapy on severe pancreatitis

The current study explored the effects of intensive insulin therapy (IIT) combined with low molecular weight heparin (LMWH) anticoagulant therapy on severe acute pancreatitis (SAP). A total of 134 patients with SAP that received treatment between June 2008 and June 2012 were divided randomly into groups A (control; n=33), B (IIT; n=33), C (LMWH; n=34) and D (IIT + LMWH; n=34). Group A were treated routinely. Group B received continuous pumped insulin, as well as the routine treatment, to maintain the blood sugar level between 4.4 and 6.1 mmol/l. Group C received a subcutaneous injection of LMWH every 12 h in addition to the routine treatment. Group D received IIT + LMWH and the routine treatment. The white blood cell count, hemodiastase, serum albumin, arterial partial pressure of oxygen and prothrombin time were recorded prior to treatment and 1, 3, 5, 7 and 14 days after the initiation of treatment. The intestinal function recovery time, incidence rate of multiple organ failure (MOF), length of hospitalization and fatality rates were observed. IIT + LMWH noticeably increased the white blood cell count, hemodiastase level, serum albumin level and the arterial partial pressure of oxygen in the patients with SAP (P<0.05). It markedly shortened the intestinal recovery time and the length of stay and reduced the incidence rate of MOF, the surgery rate and the fatality rate (P<0.05). It did not aggravate the hemorrhagic tendency of SAP (P>0.05). IIT + LMWH had a noticeably improved clinical curative effect on SAP compared with that of the other treatments.

Effect of hyperglycaemia on inflammatory and stress responses and clinical outcome of pneumonia in non-critical-care inpatients: results from an observational cohort study

AIMS/HYPOTHESIS

Despite the condition's high prevalence, the influence of hyperglycaemia on clinical outcomes in non-critical-care inpatients with infections remains ill defined. In this study, we analysed associations of glucose levels at admission and during initial inpatient treatment with the inflammatory response and clinical outcome in community-acquired pneumonia (CAP) patients.

METHODS

This secondary observational analysis included 880 confirmed CAP patients. We used severity-adjusted multivariate regression models to investigate associations of initial and 96 h mean glucose levels with serially measured biomarker levels over 7 days (C-reactive protein [CRP], procalcitonin, white blood cell count [WBC], pro-adrenomedullin [ProADM]) and adverse clinical course (death and intensive-care unit admission).

RESULTS

In the 724 non-diabetic patients (82.3% of the study population), moderate or severe hyperglycaemia (glucose 6-11 mmol/l and >11 mmol/l, respectively) was associated with increased risk for adverse clinical course (adjusted OR [95% CI] 1.4 [0.8, 2.4] and 3.0 [1.1, 8.0], respectively) and with higher CRP, WBC and ProADM levels over 7 days (p < 0.05, ANOVA, all days). In diabetic patients (n = 156), no similar associations were found for initial hyperglycaemia, although mean 96 h glucose levels  ≥ 9 mmol/l were associated with adverse clinical course (adjusted OR 5.4 [1.1, 25.8]; p = 0.03). No effect modification by insulin treatment was detected (interaction terms p > 0.2 for all analyses).

CONCLUSIONS/INTERPRETATION

Initial hyperglycaemia in non-diabetic CAP patients, and prolonged hyperglycaemia in diabetic or non-diabetic CAP patients, are associated with a more pronounced inflammatory response and CAP-related adverse clinical outcome. Optimal glucose targets for insulin treatment of hyperglycaemia in non-critical-care settings should be defined.

Revisiting tight glycemic control in perioperative and critically ill patients: when one size may not fit all

Glycemic control has received intense scrutiny in the last decade as an important aspect of patient care. Earlier studies suggested that tight glycemic control (target level of 80 - 110 mg/dL) improved outcomes in intensive care unit (ICU) patients. Subsequent trials did not confirm the same benefit. Moreover, increased mortality was found in association with such tight control compared with a less strict target. As a result, tight glucose control has become less popular. The interaction between diabetic status and outcomes in relation to glucose control strategies and/or chronic glycemic state in perioperative and critically ill patients was examined. Tight glucose control appears to be more beneficial in patients without diabetes than in those with known diabetes. It also may be more beneficial in improving outcomes in surgical rather than nonsurgical ICU patients, and in decreasing sepsis rather than mortality. Tight glycemic control was associated with a high incidence of hypoglycemia, which may offset some of its potential benefits. Tight glycemic control in the perioperative and intensive care settings should not be totally abandoned either as a clinical practice or as a subject of future research. Beneficial effects of tight glycemic control may be demonstrated when the appropriate glycemic targets are matched to the appropriate population.

Endothelial dysfunction and insulin resistance

In this article, we review several mechanisms by which insulin resistance is related to endothelial dysfunction. The mechanisms we discuss may explain the high prevalence of cardiovascular disease found in people with the metabolic syndrome and diabetes mellitus.

On the management of hyperglycaemia in critically ill patients undergoing surgery

Hyperglycaemia is a major health risk and a negative determinant of surgical outcome. Despite its increasing prevalence, the limited treatments for restoration of normoglycaemia make its effective management a highly complex individualized clinical art. In this context, we review the mechanisms leading to hyperglycaemic damage as the basis for effective management of surgical complications of diabetic and non diabetic critically ill patients.

Effects of regional analgesia on stress responses to pediatric surgery

Invasive surgery induces a combination of local response to tissue injury and generalized activation of systemic metabolic and hormonal pathways via afferent nerve pathways and the central nervous system. The local inflammatory responses and the parallel neurohumoral responses are not isolated but linked through complex signaling networks, some of which remain poorly understood. The magnitude of the response is broadly related to the site of injury (greater in regions with visceral pain afferents such as abdomen and thorax) and the extent of the trauma. The changes include alterations in metabolic, hormonal, inflammatory, and immune systems that can be collectively termed the stress response. Integral to the stress responses are the effects of nociceptive afferent stimuli on systemic and pulmonary vascular resistance, heart rate, and blood pressure, which are a combination of efferent autonomic response and catecholamine release via the adrenal medulla. Therefore, pain responses, cardiovascular responses, and stress responses need to be considered as different aspects of a combined bodily reaction to surgery and trauma. It is important at the outset to understand that not all components of the stress response are suppressed together and that this is important when discussing different analgesic modalities (i.e. opioids vs regional anesthesia). For example, in terms of the use of fentanyl in the infant, the dose required to provide analgesia (1-5 mcg·kg(-1)) is less than that required for hemodynamic stability in response to stimuli (5-10 mcg·kg(-1)) (1) and that this in turn is less than that required to suppress most aspects of the stress response (25-50 mcg·kg(-1)) (2). In contrast to this considerable dose dependency, central local anesthetic blocks allow blockade of the afferent and efferent sympathetic pathways at relatively low doses resulting in profound suppression of hemodynamic and stress responses to surgery.

A defect in the activities of Δ and Δ desaturases and pro-resolution bioactive lipids in the pathobiology of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a low-grade systemic inflammatory condition, since liver and adipose tissue tumor necrosis factor-α (TNF-α) and TNF receptor 1 transcripts and serum TNF-α levels are increased and IL-6(-/-) mice are less prone to NAFLD. Fatty liver damage caused by high-fat diets is associated with the generation of pro-inflammatory prostaglandin E(2) (PGE(2)). A decrease in the levels of arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the usefulness of EPA and DHA both in the prevention and management of NAFLD has been reported. AA, EPA and DHA and their anti-inflammatory products lipoxins (LXs), resolvins and protectins suppress IL-6 and TNF-α and PGE(2) production. These results suggest that the activities of Δ(6) and Δ(5) desaturases are reduced in NAFLD and hence, the dietary essential fatty acids, linoleic acid (LA) and α-linolenic acid (ALA) are not metabolized to their long-chain products AA, EPA and DHA, the precursors of anti-inflammatory molecules, LXs, resolvins and protectins that could pre vent NAFLD. This suggests that an imbalance between pro- and anti-inflammatory bioactive lipids contribute to NAFLD. Hence, it is proposed that plasma and tissue levels of AA, EPA, DHA and LXs, resolvins and protectins could be used as predictors and prognostic biomarkers of NAFLD. It is suggested that the synthesis and use of more stable analogues of LXs, resolvins and protectins need to be explored in the prevention and management of NAFLD.

Diabetes is not associated with increased mortality in emergency department patients with sepsis

STUDY OBJECTIVE

Despite its high prevalence, the influence of diabetes on outcomes of emergency department (ED) patients with sepsis remains undefined. Our aim is to investigate the association of diabetes and initial glucose level with mortality in patients with suspected infection from the ED.

METHODS

Three independent, observational, prospective cohorts from 2 large US tertiary care centers were studied. We included patients admitted to the hospital from the ED with suspected infection. We investigated the association of diabetes and inhospital mortality within each cohort separately and then overall with logistic regression and generalized estimating equations adjusted for age, sex, disease severity, and sepsis syndrome. We also tested for an interaction between diabetes and hyperglycemia/hypoglycemia.

RESULTS

A total of 7,754 patients were included. The mortality rate was 4.3% (95% confidence interval [CI] 3.9% to 4.8%) and similar in diabetic and nondiabetic patients (4.1% versus 4.4%; absolute risk difference 0.4%; 95% CI -0.7% to 1.4%). There was no significant association between diabetes and mortality in adjusted analysis (odds ratio [OR] overall 0.85; 95% CI 0.71 to 1.01). Diabetes significantly modified the effect of hyperglycemia and hypoglycemia with mortality; initial glucose levels greater than 200 mg/dL were associated with higher mortality in nondiabetic patients (OR 2.1; 95% CI 1.4 to 3.0) but not in diabetic patients (OR 1.0; 95% CI 0.2 to 4.7), whereas glucose levels less than 100 mg/dL were associated with higher mortality mainly in the diabetic population (OR 2.3; 95% CI 1.6 to 3.3) and to a lesser extent in nondiabetic patients (OR 1.1; 95% CI 1.03 to 1.14).

CONCLUSION

We found no evidence for a harmful association of diabetes and mortality in patients across different sepsis severities. High initial glucose levels were associated with adverse outcomes in the nondiabetic population only. Further investigation is warranted to determine the mechanism for these effects.

Insulin therapy during hospitalization

Hyperglycemia occurring during hospitalization is a common phenomenon among patients with or without a known history of diabetes mellitus. For several years, hyperglycemia in hospitalized patients had been considered as an accompanying characteristic of the acute disease that resulted in admission. That point of view changed over time mainly because of emerging indications from clinical studies showing that hyperglycemia during hospitalization could aggravate prognosis and increase mortality. Further studies engaged on how hyperglycemia should be treated, yielded results that highlighted the increasing risk of mortality due to hypoglycemia in such efforts and also questioned the initial relation between hyperglycemia during hospitalization and a poor prognosis. Based on the fact that there is still no common ground on what is the best approach on hyperglycemia of hospitalized patients, the best practice remains to follow a different regime with different glycemic goals for different patient groups. In this review, hospitalized patients are divided into three groups; intensive care unit patients (general and cardiac), non-intensive care unit patients (general and cardiac) and peri-operative patients.

Clinical effects of intensive insulin therapy treating traumatic shock combined with multiple organ dysfunction syndrome

The therapeutic effects of intensive insulin therapy in treatment of traumatic shock combined with multiple organ dysfunction syndrome (MODS) were investigated. A total of 114 patients with traumatic shock combined with MODS were randomly divided into two groups: control group (n=56) treated with conventional therapy, and intensive insulin therapy group (n=58) treated with conventional therapy plus continuous insulin pumping to control the blood glucose level at range of 4.4-6.1 mmol/L. White blood cells (WBC) counts, prothrombin time (PT), serum creatinine (SCr), alanine aminotransferase (ALT), serum albumin and PaO(2) were measured before and at the day 1, 3, 5, 7 and 14 after treatment. The incidence of gastrointestinal dysfunction, the incidence of MODS, hospital stay and the mortality were also observed and compared. After intensive insulin therapy, the WBC counts, SCr, ALT and PT were significantly reduced (P<0.05), but the level of serum albumin was significantly increased (P<0.05) at the day 3, 5, 7 and 14. In the meantime, the PaO2 was significantly elevated at the day 3, 5 and 7 (P<0.01) after intensive insulin therapy. The incidence of gastrointestinal dysfunction, the incidence of MODS, the length of hospital stay and the mortality were markedly decreased (P<0.01). The results suggest early treatment with intensive insulin therapy is effective for traumatic shock combined with MODS and can decrease the length of hospital stay and the mortality.

Relationship between gut and sepsis: Role of ghrelin

Ghrelin is a growth hormone secretagogue produced by the gut, and is expressed in the hypothalamus and other tissues as well. Ghrelin not only plays an important role in the regulation of appetite, energy balance and glucose homeostasis, but also shows anti-bacterial activity, suppresses pro-inflammatory cytokine production and restores gut barrier function. In experimental animals, ghrelin has shown significant beneficial actions in preventing mortality from sepsis. In the critically ill, corticosteroid insufficiency as a result of dysfunction of the hypothalamic-pituitary-adrenal axis is known to occur. It is therefore possible that both gut and hypothalamus play an important role in the pathogenesis of sepsis by virtue of their ability to produce ghrelin, which, in turn, could be a protective phenomenon to suppress inflammation. It remains to be seen whether ghrelin and its analogues are of benefit in treating patients with sepsis.

Current and emerging strategies for the treatment and management of systemic lupus erythematosus based on molecular signatures of acute and chronic inflammation

Lupus is a chronic, systemic inflammatory condition in which eicosanoids, cytokines, nitric oxide (NO), a deranged immune system, and genetics play a significant role. Our studies revealed that an imbalance in the pro- and antioxidants and NO and an alteration in the metabolism of essential fatty acids exist in lupus. The current strategy of management includes administration of nonsteroidal anti-inflammatory drugs such as hydroxychloroquine and immunosuppressive drugs such as corticosteroids. Investigational drugs include the following: 1) belimumab, a fully human monoclonal antibody that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator, also known as B-cell-activation factor of the TNF family; 2) stem cell transplantation; 3) rituximab, a chimeric monoclonal antibody against CD20, which is primarily found on the surface of B-cells and can therefore destroy B-cells; and 4) IL-27, which has potent anti-inflammatory actions. Our studies showed that a regimen of corticosteroids and cyclophosphamide, and methods designed to enhance endothelial NO synthesis and augment antioxidant defenses, led to induction of long-lasting remission of the disease. These results suggest that methods designed to modulate molecular signatures of the disease process and suppress inflammation could be of significant benefit in lupus. Some of these strategies could be vagal nerve stimulation, glucose-insulin infusion, and administration of lipoxins, resolvins, protectins, and nitrolipids by themselves or their stable synthetic analogs that are known to suppress inflammation and help in the resolution and healing of the inflammation-induced damage. These strategies are likely to be useful not only in lupus but also in other conditions, such as rheumatoid arthritis, scleroderma, ischemia-reperfusion injury to the myocardium, ischemic heart disease, and sepsis.

Metabolic syndrome is a low-grade systemic inflammatory condition

An increase in proinflammatory cytokines, a decrease in endothelial nitric oxide and adiponectin levels and an alteration in hypothalamic peptides and gastrointestinal hormones that regulate satiety, hunger and food intake all occur in metabolic syndrome. Consumption of a diet that is energy dense and rich in saturated and trans-fats by pregnant women and lactating mothers, in childhood and adult life may trigger changes in the hypothalamic and gut peptides and hormones. Such changes modulate immune response and inflammation and lead to alterations in the hypothalamic 'bodyweight/appetite/satiety set point' and result in the initiation and development of the metabolic syndrome. Roux-en-gastric bypass induces weight loss, decreases the levels of cytokines and restores hypothalamic neuropeptides and gut hormones and the hypothalamic bodyweight/appetite/satiety set point to normal. Thus, metabolic syndrome is a low-grade systemic inflammatory condition with its origins in the perinatal period and childhood.

Design and Organization of the Dexamethasone, Light Anesthesia and Tight Glucose Control (DeLiT) Trial: a factorial trial evaluating the effects of corticosteroids, glucose control, and depth-of-anesthesia on perioperative inflammation and morbidity from major non-cardiac surgery

BACKGROUND

The perioperative period is characterized by an intense inflammatory response. Perioperative inflammation promotes postoperative morbidity and increases mortality. Blunting the inflammatory response to surgical trauma might thus improve perioperative outcomes. We are studying three interventions that potentially modulate perioperative inflammation: corticosteroids, tight glucose control, and light anesthesia.

METHODS/DESIGN

The DeLiT Trial is a factorial randomized single-center trial of dexamethasone vs placebo, intraoperative tight vs. conventional glucose control, and light vs deep anesthesia in patients undergoing major non-cardiac surgery. Anesthetic depth will be estimated with Bispectral Index (BIS) monitoring (Aspect medical, Newton, MA). The primary outcome is a composite of major postoperative morbidity including myocardial infarction, stroke, sepsis, and 30-day mortality. C-reactive protein, a measure of the inflammatory response, will be evaluated as a secondary outcome. One-year all-cause mortality as well as post-operative delirium will be additional secondary outcomes. We will enroll up to 970 patients which will provide 90% power to detect a 40% reduction in the primary outcome, including interim analyses for efficacy and futility at 25%, 50% and 75% enrollment.

DISCUSSION

The DeLiT trial started in February 2007. We expect to reach our second interim analysis point in 2010. This large randomized controlled trial will provide a reliable assessment of the effects of corticosteroids, glucose control, and depth-of-anesthesia on perioperative inflammation and morbidity from major non-cardiac surgery. The factorial design will enable us to simultaneously study the effects of the three interventions in the same population, both individually and in different combinations. Such a design is an economically efficient way to study the three interventions in one clinical trial vs three.

TRIAL REGISTRATION

This trial is registered at Clinicaltrials.gov #: NTC00433251.

Control of hyperglycaemia in paediatric intensive care (CHiP): study protocol

BACKGROUND

There is increasing evidence that tight blood glucose (BG) control improves outcomes in critically ill adults. Children show similar hyperglycaemic responses to surgery or critical illness. However it is not known whether tight control will benefit children given maturational differences and different disease spectrum.

METHODS/DESIGN

The study is an randomised open trial with two parallel groups to assess whether, for children undergoing intensive care in the UK aged <or= 16 years who are ventilated, have an arterial line in-situ and are receiving vasoactive support following injury, major surgery or in association with critical illness in whom it is anticipated such treatment will be required to continue for at least 12 hours, tight control will increase the numbers of days alive and free of mechanical ventilation at 30 days, and lead to improvement in a range of complications associated with intensive care treatment and be cost effective. Children in the tight control group will receive insulin by intravenous infusion titrated to maintain BG between 4 and 7.0 mmol/l. Children in the control group will be treated according to a standard current approach to BG management. Children will be followed up to determine vital status and healthcare resources usage between discharge and 12 months post-randomisation. Information regarding overall health status, global neurological outcome, attention and behavioural status will be sought from a subgroup with traumatic brain injury (TBI). A difference of 2 days in the number of ventilator-free days within the first 30 days post-randomisation is considered clinically important. Conservatively assuming a standard deviation of a week across both trial arms, a type I error of 1% (2-sided test), and allowing for non-compliance, a total sample size of 1000 patients would have 90% power to detect this difference. To detect effect differences between cardiac and non-cardiac patients, a target sample size of 1500 is required. An economic evaluation will assess whether the costs of achieving tight BG control are justified by subsequent reductions in hospitalisation costs.

DISCUSSION

The relevance of tight glycaemic control in this population needs to be assessed formally before being accepted into standard practice.

The oxidative stress of hyperglycemia and the inflammatory process in endothelial cells

Hyperglycemia and insulin resistance are common in many critically ill patients. Hyperglycemia increases the production of reactive oxygen species in cells, stimulates the production of the potent proinflammatory cytokines IL-8 and TNF-alpha, and enhances the expression of haem oxygenase-1, an inducible stress protein. It has been shown that administration of insulin and the semi-essential amino acid glutamine have been beneficial to the septic patient. The aim of our study is to test whether these two molecules, glutamine and insulin used in combination attenuate the proinflammatory responses in endothelial cells which have been triggered by hyperglycaemia. Our results demonstrate that a combination of insulin and glutamine are significantly more effective in reducing the expression of IL-8, TNF-alpha and HO-1 than insulin or glutamine alone.

Exercise training decreases proinflammatory profile in Zucker diabetic (type 2) fatty rats

OBJECTIVE

In the present study we evaluated the effect of exercise on the plasma levels of proinflammatory cytokines, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), and the anti-inflammatory molecule uric acid in the Zucker diabetic fatty (ZDF) rats that are more prone to develop type 2 diabetes mellitus.

METHODS

Sixteen obese ZDF (Gmi fa/fa) rats (8 wk old, 228.40 +/- 4.05 g) were randomly assigned to one of two groups (n = 8 each): an exercise-trained group and a sedentary one. In addition, 16 lean ZDF (Gmi +/+) rats (8 wk old, 199.00 +/- 3.50 g) were subjected to identical sedentary and exercise conditioning (n = 8 each). Initially, rats swam 15 min/d (5 d/wk) in a 36 degrees C bath. The exercise protocol was gradually increased by 15 min/d until a swimming period of 1 h/d (1 wk) was attained. Thereafter, rats swam 1 h/d, 3 d/wk, for an additional period of 11 wk. Rats were sacrificed 48 h after the last training period and the blood and pancreas were collected. Circulating levels of glucose, glycosylated hemoglobin, total cholesterol, triglycerides, insulin, uric acid, IL-6, and TNF-alpha were assessed. The concentrations of proinflammatory cytokines in the pancreas were also evaluated.

RESULTS

In the diabetic ZDF (fa/fa) rats, exercise decreased hyperuricemia (-37.3%) and IL-6 and TNF-alpha levels (-16.9% and -12.7% respectively) and maintained the weight of the pancreas at near normal. Immunohistochemistry revealed a marked decrease in the expression of TNF-alpha and IL-6 in the pancreatic islet cells of ZDF (fa/fa) rats.

CONCLUSION

These results indicate that aerobic exercise is anti-inflammatory in nature.

Insulin increases the release of proinflammatory mediators

BACKGROUND

Strict glucose control with insulin is associated with decreased mortality in a mixed patient population in the intensive care unit. Controversy exists regarding the relative benefits of glucose control versus a direct advantageous effect of exogenous insulin. As a combined medical/surgical population differs significantly from the critically injured patient primed for secondary insult, our purpose was to determine the influence of insulin on activated macrophages. Our hypothesis was that insulin would directly abrogate the inflammatory cascade.

METHODS

Differentiated human monocytic THP-1 cells were stimulated with endotoxin (lipopolysaccharide [LPS], 100 ng/mL) for 6 hours. Cells were treated +/-10(-7) M insulin for 1 hour and 24 hours. Total RNA was isolated and gene expression for TNF-alpha and IL-6 performed using Q-RT-PCR. Supernatants were assayed for TNF-alpha and IL-6 protein by ELISA.

RESULTS

At 1 hour, compared with macrophages treated with LPS alone, macrophages treated with insulin produced significantly more TNF-alpha protein (11.4 +/- 5.9 pg/mL vs. 32.5 +/- 3.1 pg/mL; p < 0.03). At 24 hours compared with macrophages treated with LPS alone, macrophages treated with insulin produced significantly more TNF-alpha protein (83 +/- 2.02 pg/mL vs. 114 +/- 6.54 pg/mL; p < 0.01). However, gene expression of TNF-alpha and IL-6 was not different in LPS stimulated macrophages with and without insulin treatment at both 1 hour and 24 hours.

CONCLUSION

Contrary to our hypothesis, insulin does not have direct anti-inflammatory properties in this experimental model. In fact, insulin increases proinflammatory cytokine protein levels from activated macrophages.

Diabetes, glycemic control, and risk of hospitalization with pneumonia: a population-based case-control study

OBJECTIVE

To examine whether diabetes is a risk factor for hospitalization with pneumonia and to assess the impact of A1C level on such risk.

RESEARCH DESIGN AND METHODS

In this population-based, case-control study we identified patients with a first-time pneumonia-related hospitalization between 1997 and 2005, using health care databases in northern Denmark. For each case, 10 sex- and age-matched population control subjects were selected from Denmark's Civil Registration System. We used conditional logistic regression to compute relative risk (RR) for pneumonia-related hospitalization among subjects with and without diabetes, controlling for potential confounding factors.

RESULTS

The study included 34,239 patients with a pneumonia-related hospitalization and 342,390 population control subjects. The adjusted RR for pneumonia-related hospitalization among subjects with diabetes was 1.26 (95% CI 1.21-1.31) compared with nondiabetic individuals. The adjusted RR was 4.43 (3.40-5.77) for subjects with type 1 diabetes and 1.23 (1.19-1.28) for subjects with type 2 diabetes. Diabetes duration >or=10 years increased the risk of a pneumonia-related hospitalization (1.37 [1.28-1.47]). Compared with subjects without diabetes, the adjusted RR was 1.22 (1.14-1.30) for diabetic subjects whose A1C level was <7% and 1.60 (1.44-1.76) for diabetic subjects whose A1C level was >or=9%.

CONCLUSIONS

Type 1 and type 2 diabetes are risk factors for a pneumonia-related hospitalization. Poor long-term glycemic control among patients with diabetes clearly increases the risk of hospitalization with pneumonia.

Insulin regulates macrophage activation through activin A

Strict control of serum glucose with insulin has been associated with a reduction in the development of multiple organ dysfunction syndrome potentially through alterations in macrophage activation. Although the mechanism responsible for this effect remains poorly elucidated, recent work has suggested that this may occur through the PI3K/AKT pathway. As a result, we set out to investigate the role and means of activation of this pathway by insulin on endotoxin-mediated activation of tissue-fixed macrophages.

METHODS

THP-1 cells were stimulated with endotoxin with or without 24 h of insulin pretreatment. Cellular protein was extracted and analyzed by immunoblot for factors essential to Toll-like receptor 4 signaling. Supernatants were analyzed by enzyme-linked immunosorbent assay for TNF-alpha and IL-8 production. In addition, potential effect of the transforming growth factor superfamily was analyzed through selective inhibition of either the transforming growth factor beta or activin A receptors.

RESULTS

Endotoxin exposure resulted in the activation of extracellular signal-regulated kinase 1/2, p38 and Jun kinase, the degradation of IkappaB, the activation of nuclear factor kappaB, and the production of TNF-alpha and IL-8. Insulin pretreatment delayed endotoxin-mediated extracellular signal-regulated kinase 1/2, p38 and Jun kinase, the degradation of IkappaB, the activation of nuclear factor kappaB, and the production of TNF-alpha and IL-8. Insulin alone was associated with an increase in cytoplasmic SH2-containing inositol 5'-phosphatase (SHIP) but a decrease in lipid raft bound SHIP. The changes induced by insulin on SHIP and endotoxin-mediated signaling were reversed by activin A blockade.

CONCLUSIONS

Insulin results in regulation of macrophage activity in response to endotoxin through the release of activin A and subsequent production of SHIP. This increase in cytoplasmic SHIP results in attenuated endotoxin-mediated intracellular signaling and inflammatory mediator production.

Blood glucose control in critical care patients - a review of the literature

The role of hyperglycaemia in critical illness, and its corresponding treatment, has been an area of controversy, fuelled by conflicting research findings. The aims of this study were to critically evaluate the literature and present an historical review of the sequence of published papers relating to blood glucose control in critical care. Their subsequent impact together with the implications for patient care is discussed. This article is based on a systematic review of papers relating to glycaemic control in critical care patients. The review was conducted using the MedLine, CINAHL and EMBASE databases using key search terms (details of the search terms can be found after the conclusion of the paper) for the period 1950-2006. The searches resulted in 4863 papers being screened for relevance to the historic progression of glycaemic management in critical care patients, by title and then abstract. Of these, 209 were accessed, and their reference lists were snowballed for further papers. Papers that were repeatedly quoted throughout the literature and were therefore considered important in the historical development of accepted critical care practice were finally subjected to rigorous appraisal. These totalled 91 papers and included 18 randomized controlled trials, an additional 28 research papers, 25 editorials and 20 reviews. This critical evaluation of published work indicates that the evidence for the benefit of this therapy may not be as compelling as previously indicated, and its widespread use may have been premature. From a nursing perspective, this demonstrates the importance of maintaining a questioning attitude to new therapies and reviewing best practice in the light of evolving evidence.

Glycemic control and prevention of perioperative infection

PURPOSE OF REVIEW

Hyperglycemia is common during perioperative management of surgical and critically ill patients. There is extensive ongoing study of detrimental effects associated with hyperglycemia, with several remaining unanswered questions. This review discusses recent literature on tight glucose control with insulin therapy and its effects in prevention and management of infection.

RECENT FINDINGS

Hyperglycemia affects multiple pathways of the immune system, resulting in decreased phagocytic and chemotactic functions in neutrophils and monocytes, as well as increased rates of apoptosis of the former and decreased ability of the latter to present antigen. Intensive insulin therapy has been shown to counteract many of these deleterious effects. Clinically, the benefits of tight glucose control have been evaluated in different patient populations with conclusions that remain varied. Hypoglycemia as a complication of tight glucose control continues to be an issue and has led to discontinuation of two large-scale studies. The clinical relevance of hypoglycemic events remains unclear.

SUMMARY

Hyperglycemia impairs the cellular immune system, stimulates inflammatory cytokines, and affects the microcirculation, thus increasing risk for infection and preventing normal wound healing. Additional investigation is needed to define appropriate patient populations and to develop effective treatment strategies for preventing perioperative morbidity.

Is metabolic syndrome X a disorder of the brain with the initiation of low-grade systemic inflammatory events during the perinatal period?

An imbalance between pro- and anti-inflammatory molecules occurs in metabolic syndrome X. High-energy diet, saturated fats and trans-fats during perinatal period could suppress Delta(6) and Delta(5) desaturases both in the maternal and fetal tissues, resulting in a decrease in the concentrations of long-chain polyunsaturated fatty acids (LCPUFAs): arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that have a negative feedback control on inflammation. EPA, DHA and AA augment endothelial nitric oxide synthesis, potentiate insulin action both in the peripheral tissues and brain and alter leptin production. LCPUFAs are essential for brain growth and development and synaptogenesis and modulate the action of several neurotransmitters and hypothalamic peptides. This suggests that metabolic syndrome X could be a disorder of the brain due to suboptimal LCPUFAs during perinatal period that triggers low-grade systemic inflammation, implying that perinatal strategies are needed to prevent its development.

Insulin-based regimens decrease mortality rates in critically ill patients: a systematic review

OBJECTIVES

To determine whether treatment with glucose-insulin-potassium (GIK), insulin and glucose, or insulin by itself is beneficial in limiting organ damage after acute myocardial infarction (AMI) and reducing mortality and morbidity among critically ill hyperglycaemic patients.

METHODS

Systematic review of randomized controlled trials.

MAIN OUTCOME MEASURE

To assess whether tight glycaemic control reduces morbidity and mortality.

STUDIES REVIEWED

Randomized controlled trials of insulin-based regimens in the treatment of critically ill patients.

RESULTS

Nine hundred and twenty-four potentially relevant studies were identified and screened for retrieval. Of these, 16 randomized controlled trials met the inclusion criteria (Table 1). Ten studies examined the effects of GIK, and six of these studies reported a mortality reduction with GIK treatment in addition to enhanced myocardial performance. Five studies examined the administration of insulin. Among these studies, tight glycaemic control of blood glucose in one study was shown to reduce morbidity and mortality of patients in intensive care. Only one study examined insulin/glucose therapy, and it showed a post-myocardial infarction mortality reduction of one year.

CONCLUSIONS

There is increasing evidence that maintaining normoglycaemia and treatment with insulin-based regimens is beneficial in limiting organ damage and significantly reduces both morbidity and mortality in critically ill patients who require intensive care therapy.

Effect of insulin treatment on plasma oxidized LDL/LDL-cholesterol ratio in type 2 diabetic patients

OBJECTIVE

In type 2 diabetes mellitus, oxidized LDL/LDL-Cholesterol ratio, an accurate estimation of in vivo LDL oxidation, has been reported elevated and associated with macrovascular disease. Because insulin therapy induces significant modification of lipid metabolism, in type 2 diabetes, we evaluated the effect of insulin treatment on oxidized LDL/LDL-C ratio in type 2 diabetic patients and analyzed the results in comparison with the modifications induced by insulin on glycaemia, plasma lipids and LDL receptors.

RESEARCH DESIGN AND METHODS

Plasma oxidized LDL concentrations were measured by sandwich ELISA in 21 type 2 diabetic patients before and 3 months after the introduction of insulin therapy, and in 27 age-matched controls.

RESULTS

Type 2 diabetic patients had, compared to controls, significantly increased oxidized LDL/LDL-C ratio (P<0.0001). Three months after insulin treatment, oxidized LDL/LDL-C ratio was significantly reduced (21.1+/-4.7 vs. 24.0+/-5.8 U/mmol, P<0.01). This reduction was strongly associated, in multivariate analysis, with reduction of LDL(TG/cholesterol ratio) (P=0.008), and to a lesser extent with the decrease of LDL fructosamine (P=0.034), but not with the increase of the number of LDL receptors.

CONCLUSIONS

In the present study we demonstrate for the first time a lowering effect of insulin therapy on oxidized LDL/LDL-C ratio in type 2 diabetic patients. This decrease is mainly associated with the reduction of LDL TG-enrichment, and to a lesser extent with the decrease of LDL glycation, but not with the insulin-induced increase in number of LDL receptors.