Marie E. McDonnell

Pharmacological Management of Obesity: An Endocrine Society Clinical Practice Guideline

OBJECTIVE To formulate clinical practice guidelines for the pharmacological management of obesity. PARTICIPANTS An Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. This guideline was co-sponsored by the European Society of Endocrinology and The Obesity Society. EVIDENCE This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe the strength of recommendations and the quality of evidence. CONSENSUS PROCESS One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of the Endocrine Society, the European Society of Endocrinology, and The Obesity Society reviewed and commented on preliminary drafts of these guidelines. Two systematic reviews were conducted to summarize some of the supporting evidence. CONCLUSIONS Weight loss is a pathway to health improvement for patients with obesity-associated risk factors and comorbidities. Medications approved for chronic weight management can be useful adjuncts to lifestyle change for patients who have been unsuccessful with diet and exercise alone. Many medications commonly prescribed for diabetes, depression, and other chronic diseases have weight effects, either to promote weight gain or produce weight loss. Knowledgeable prescribing of medications, choosing whenever possible those with favorable weight profiles, can aid in the prevention and management of obesity and thus improve health.

Adipose Macrophage Infiltration Is Associated With Insulin Resistance and Vascular Endothelial Dysfunction in Obese Subjects

Objective—Experimental studies suggest that adipose inflammation is etiologically linked to obesity-induced systemic disease. Our goal was to characterize the state of inflammation in human fat in relation to vascular function and metabolic parameters in obese individuals. Methods and Results—We collected subcutaneous abdominal fat in 77 obese subjects (BMI ≥30 kg/m2) and quantified adipose macrophage population using targeted immunohistochemistry. Brachial artery vasodilator function was examined using high-resolution vascular ultrasound. In 50 subjects, an inflamed adipose phenotype characterized by tissue macrophage accumulation in crown-like structures was associated with systemic hyperinsulinemia and insulin resistance (HOMA-IR 5.5±4.5 versus 2.6±1.9, P=0.002) and impaired endothelium-dependent flow-mediated vasodilation (8.5±4.4% versus 10.8±3.8%, P<0.05), as compared to subjects with quiescent noninflamed adipose architecture (n=27). Macrophage retention in fat was linked to upregulated tissue CD68 and tumor necrosis factor (TNF)-&agr; mRNA expression in addition to increased plasma hs-CRP. Conclusions—In a cohort of obese subjects, we demonstrate that proinflammatory changes in adipose tissue are associated with systemic arterial dysfunction and insulin resistance. These findings suggest that adipose inflammation may be linked to vascular injury and increased cardiovascular risk in obese subjects.

The Society of Thoracic Surgeons Practice Guideline Series: Blood Glucose Management During Adult Cardiac Surgery

The Society of Thoracic Surgeons Practice Guideline Series : Blood Glucose Management During Adult Cardiac Surgery

B cells promote inflammation in obesity and type 2 diabetes through regulation of T-cell function and an inflammatory cytokine profile

Patients with type 2 diabetes (T2D) have disease-associated changes in B-cell function, but the role these changes play in disease pathogenesis is not well established. Data herein show B cells from obese mice produce a proinflammatory cytokine profile compared with B cells from lean mice. Complementary in vivo studies show that obese B cell–null mice have decreased systemic inflammation, inflammatory B- and T-cell cytokines, adipose tissue inflammation, and insulin resistance (IR) compared with obese WT mice. Reduced inflammation in obese/insulin resistant B cell–null mice associates with an increased percentage of anti-inflammatory regulatory T cells (Tregs). This increase contrasts with the sharply decreased percentage of Tregs in obese compared with lean WT mice and suggests that B cells may be critical regulators of T-cell functions previously shown to play important roles in IR. We demonstrate that B cells from T2D (but not non-T2D) subjects support proinflammatory T-cell function in obesity/T2D through contact-dependent mechanisms. In contrast, human monocytes increase proinflammatory T-cell cytokines in both T2D and non-T2D analyses. These data support the conclusion that B cells are critical regulators of inflammation in T2D due to their direct ability to promote proinflammatory T-cell function and secrete a proinflammatory cytokine profile. Thus, B cells are potential therapeutic targets for T2D.

Elevated Proinflammatory Cytokine Production by a Skewed T Cell Compartment Requires Monocytes and Promotes Inflammation in Type 2 Diabetes

An appropriate balance between proinflammatory (Th17 and Th1) and anti-inflammatory (regulatory T cells [Tregs] and Th2) subsets of T cells is critical to maintain homeostasis and avoid inflammatory disease. Type 2 diabetes (T2D) is a chronic inflammatory disease promoted by changes in immune cell function. Recent work indicates T cells are important mediators of inflammation in a mouse model of T2D. These studies identified an elevation in the Th17 and Th1 subsets with a decrease in the Treg subset, which culminates in inflammation and insulin resistance. Based on these data, we tested the hypothesis that T cells in T2D patients are skewed toward proinflammatory subsets. Our data show that blood from T2D patients has increased circulating Th17 cells and elevated activation of Th17 signature genes. Importantly, T cells required culture with monocytes to maintain Th17 signatures, and fresh ex vivo T cells from T2D patients appeared to be poised for IL-17 production. T cells from T2D patients also have increased production of IFN-γ, but produce healthy levels of IL-4. In contrast, T2D patients had decreased percentages of CD4+ Tregs. These data indicate that T cells in T2D patients are naturally skewed toward proinflammatory subsets that likely promote chronic inflammation in T2D through elevated cytokine production. Potential therapies targeted toward resetting this balance need to be approached with caution due to the reciprocal relationship between Th17 cells and Tregs. Understanding the unique aspects of T2D T cells is essential to predict outcomes of such treatments.

Inducible Toll-like Receptor and NF-κB Regulatory Pathway Expression in Human Adipose Tissue

Objective: Inflammatory activity in fat tissue has recently been implicated in mechanisms of insulin resistance and obesity‐related metabolic dysfunction. Toll‐like receptors (TLRs) play a key role in innate immune responses and recent studies implicate the TLR pathway in mechanisms of inflammation and atherosclerosis. The aim of this study was to examine differential TLR expression and function in human adipose tissue.

Toll-like receptors regulate B cell cytokine production in patients with diabetes

Aims/hypothesisUnderstanding cellular and molecular events in diabetes mellitus will identify new approaches for therapy. Immune system cells are important modulators of chronic inflammation in diabetes mellitus, but the role of B cells is not adequately studied. The aim of this work was to define the function of B cells in diabetes mellitus patients through focus on B cell responses to pattern recognition receptors.MethodsWe measured expression and function of Toll-like receptors (TLRs) on peripheral blood B cells from diabetes mellitus patients by flow cytometry and multiplexed cytokine analysis. We similarly analysed B cells from non-diabetic donors and periodontal disease patients as comparative cohorts.ResultsB cells from diabetes mellitus patients secrete multiple pro-inflammatory cytokines, and IL-8 production is significantly elevated in B cells from diabetic patients compared with those from non-diabetic individuals. These data, plus modest elevation of TLR surface expression, suggest B cell IL-8 hyperproduction is a cytokine-specific outcome of altered TLR function in B cells from diabetes mellitus patients. Altered TLR function is further evidenced by demonstration of an unexpected, albeit modest ‘anti-inflammatory’ function for TLR4. Importantly, B cells from diabetes mellitus patients fail to secrete IL-10, an anti-inflammatory cytokine implicated in inflammatory disease resolution, under a variety of TLR-stimulating conditions. Comparative analyses of B cells from patients with a second chronic inflammatory disease, periodontal disease, indicated that some alterations in B cell TLR function associate specifically with diabetes mellitus.Conclusions/interpretationAltered TLR function in B cells from diabetes mellitus patients increases inflammation by two mechanisms: elevation of pro-inflammatory IL-8 and lack of anti-inflammatory/protective IL-10 production.

TLR Cross-Talk Specifically Regulates Cytokine Production by B Cells from Chronic Inflammatory Disease Patients

Chronic systemic inflammation links periodontal disease and diabetes to increased incidence of serious comorbidities. Activation of TLRs, particularly TLR2 and TLR4, promotes chronic systemic inflammation. Human B cells have been generally thought to lack these TLRs. However, recent work showed that an increased percentage of circulating B cells from inflammatory disease patients express TLR2 and TLR4, and that TLR engagement on B cells resulted in unexpected changes in gene expression. New data show that B cells from inflammatory disease patients secrete multiple cytokines in response to different classes of TLR ligands. Furthermore, the B cell response to combinations of TLR ligands is cytokine- and ligand-specific. Some cytokines (IL-1β and IL-10) are predominantly regulated by TLR4, but others (IL-8 and TNF-α) are predominantly regulated by TLR2, due in part to TLR-dictated changes in transcription factor/promoter association. TLR2 and TLR9 also regulate B cell TLR4 expression, demonstrating that TLR cross-talk controls B cell responses at multiple levels. Parallel examination of B cells from periodontal disease and diabetes patients suggested that outcomes of TLR cross-talk are influenced by disease pathology. We conclude that disease-associated alteration of B cell TLR responses specifically regulates cytokine production and may influence chronic inflammation.

Insulin therapy for the management of hyperglycemia in hospitalized patients.

It has long been established that hyperglycemia with or without a prior diagnosis of diabetes increases both mortality and disease-specific morbidity in hospitalized patients and that goal-directed insulin therapy can improve outcomes. This article reviews the pathophysiology of hyperglycemia during illness, the mechanisms for increased complications and mortality due to hyperglycemia and hypoglycemia, and beneficial mechanistic effects of insulin therapy and provides updated recommendations for the inpatient management of diabetes in the critical care setting and in the general medicine and surgical settings.

Weight-Based, Insulin Dose–Related Hypoglycemia in Hospitalized Patients With Diabetes

OBJECTIVE To determine the association of weight-based insulin dose with hypoglycemia in noncritically ill inpatients with diabetes. RESEARCH DESIGN AND METHODS We performed a retrospective, case-control study of 1,990 diabetic patients admitted to hospital wards. Patients with glucose levels <70 mg/dL (case subjects) were matched one to one with nonhypoglycemic control subjects on the basis of the hospital day of hypoglycemia, age, sex, and BMI. RESULTS Relative to 24-h insulin doses <0.2 units/kg, the unadjusted odds of hypoglycemia increased with increasing insulin dose. Adjusted for insulin type, sliding-scale insulin use, and albumin, creatinine, and hematocrit levels, the higher odds of hypoglycemia with increasing insulin doses remained (0.6–0.8 units/kg: odds ratio 2.10 [95% CI 1.08–4.09], P = 0.028; >0.8 units/kg: 2.95 [1.54–5.65], P = 0.001). The adjusted odds of hypoglycemia were not greater in patients who received 0.2–0.4 units/kg (1.08 [0.64–1.81], P = 0.78) or 0.4–0.6 units/kg (1.60 [0.90–2.86], P = 0.11). Although the relationship between insulin dose and hypoglycemia did not vary by insulin type, patients who received NPH trended toward greater odds of hypoglycemia compared with those given other insulins. CONCLUSIONS Higher weight-based insulin doses are associated with greater odds of hypoglycemia independent of insulin type. However, 0.6 units/kg seems to be a threshold below which the odds of hypoglycemia are relatively low. These findings may help clinicians use insulin more safely.