Is there a metabolic program in the skeletal muscle of obese individuals?

Severe obesity (BMI ≥ 40 kg/m(2)) is associated with multiple defects in skeletal muscle which contribute to insulin resistance and a reduction in fatty acid oxidation (FAO) in this tissue. These metabolic derangements are retained in human skeletal muscle cells raised in culture. Together, these findings are indicative of a dysfunctional global metabolic program with severe obesity which is of an epigenetic or genetic origin. Weight loss via gastric bypass surgery can "turn off" and/or correct components of this metabolic program as insulin sensitivity is restored; however, the impairment in FAO in skeletal muscle remains evident. Physical activity can improve FAO and insulin action, indicating that this patient population is not exercise resistant and that exercise offers a pathway to circumvent the abnormal program. Findings presented in this review will hopefully increase the understanding of and aid in preventing and/or treating the severely obese condition.

Early postoperative outcomes of metabolic surgery to treat diabetes from sites participating in the ASMBS bariatric surgery center of excellence program as reported in the Bariatric Outcomes Longitudinal Database

OBJECTIVE

Small case series suggest bariatric surgery may be an effective treatment for type 2 diabetes mellitus in patients who do not meet body weight criteria for morbid obesity (body mass index [BMI], <35 kg/m), but large multi-institutional series, which allow better assessment of the safety and efficacy of treatment, have not been reported.

METHODS

Data from 66,264 research-consented patients with a primary bariatric surgery encounter in the Bariatric Outcomes Longitudinal Database from June 2007 to June 2009 were queried to identify patients with a BMI > or =30 but <35 kg/m2 (1.2%, n = 794) and diabetes requiring any medication (29%).

RESULTS

A total of 235 patients met inclusion criteria. The 2 most common procedures, adjustable gastric banding (n = 109) and gastric bypass (n = 109), were compared. Laparoscopic access was used in 92% of procedures. Gender (76.6% female), race (80.4% White), and age (mean 52.6 +/- 10.4 years) did not differ between procedure groups. Gastric bypass provided superior weight loss and diabetes remission but demonstrated more frequent complications (90-day complications: 18% vs. 3%, P < 0.05). No mortalities were reported, and most complications were minor.

CONCLUSIONS

The data suggest early effectiveness of surgical treatment of diabetes in patients who do not meet criteria for morbid obesity. Gastric bypass provides more effective treatment for diabetes than adjustable gastric banding within 6 to 12 months.

Amelioration of insulin requirement in patients undergoing duodenal bypass for reasons other than obesity implicates foregut factors in the pathophysiology of type II diabetes

BACKGROUND

Foregut diversion and weight loss have been proposed as potential mechanisms for resolution of type II diabetes mellitus (T2DM) observed in patients undergoing gastric bypass for obesity. To support or refute the role of the foregut, we analyzed glycemic control in T2DM patients before and after foregut bypass for reasons other than morbid obesity.

STUDY DESIGN

Using ICD9/CPT codes, we identified patients undergoing Roux-en-Y gastrojejunostomy (RY) or Billroth II (BII) reconstruction over 10 years. Fasting blood glucose, insulin or oral diabetic agent requirement, and body mass index (BMI) before and after surgery were tabulated and compared using the Student's t-test. Linear regression was applied to determine specific factors predictive of resolution or improvement in glycemic control including age, duration of diabetes, antidiabetic regimen, type of operation, and surgical indication.

RESULTS

Between 1996 and 2006, we identified 24 patients with T2DM out of a cohort of 209 who underwent either RY (12 of 24) or BII reconstruction (12 of 24) for cancer or peptic ulcer disease and survived more than 30 days after operation. Of this group, 75% were overweight (18 of 24 with BMI < 30 kg/m(2)) and 25% were class I morbidly obese (6 of 24 with BMI 30 to 35 kg/m(2)). Seventeen patients (71%) had either complete resolution (7 of 24 or 29%) or significant reduction (10 of 24 or 42%) in medication requirements; 7 patients (29%) did not have any improvement. Logistic regression failed to identify specific factors predicting improved glycemic control.

CONCLUSIONS

Complete resolution of T2DM in patients undergoing duodenal diverting surgery occurs in about one-third of nonobese patients. Improved glycemic control occurs in more than two-thirds and cannot be explained by surgically related weight loss alone. Surgical cure of T2DM may be possible in carefully selected nonobese patients.

Beyond the BMI: the search for better guidelines for bariatric surgery

The application of the BMI of > or =35 as the major prerequisite for access to bariatric surgery is no longer appropriate because the index, now incorporated in the requirements of Medicare, Medicaid and most private carriers, does not reflect the degree or distribution of adiposity, it discriminates unfairly on the basis of gender, race, age, fitness, and body fat composition. Further, with increasing evidence that bariatric surgery can also induce full and durable remission of such comorbidities as type 2 diabetes even in patients with BMIs <30, new guidelines must be pursued.

Relationship between surgeon volume and adverse outcomes after RYGB in Longitudinal Assessment of Bariatric Surgery (LABS) study

BACKGROUND

Bariatric surgery is technically demanding surgery performed on high-risk patients. Previous studies using administrative databases have shown a relationship between surgeon volume and patient outcome after Roux-en-Y gastric bypass (RYGB). We examined the relationship between surgeons' annual RYGB volumes and 30-day patient outcomes at 10 centers within the United States.

METHODS

The Longitudinal Assessment of Bariatric Surgery (LABS)-1 is a prospective study examining the 30-day adverse outcomes after bariatric surgery. The outcomes after RYGB were adjusted by procedure type (open versus laparoscopic), functional status, body mass index, history of deep vein thrombosis, pulmonary embolism, and obstructive sleep apnea. The data were examined to determine the nature and strength of the association between surgeon volume and patients' short-term (30-day) adverse outcomes after RYGB.

RESULTS

The analysis included 3410 initial RYGB operations performed by 31 surgeons, 15 of whom averaged <50 cases annually. The crude composite adverse outcome (i.e., death, deep vein thrombosis, pulmonary embolism, reintervention or nondischarge at day 30) incidence was 5.2%. After risk adjustment, a greater surgeon RYGB volume was associated with lower composite event rates, with a continuous relationship (i.e., varying cutpoints differentiated the composite event rates), such that for each 10-case/yr increase in volume, the risk of a composite event decreased by 10%.

CONCLUSION

In the LABS, the patient's risk of an adverse outcome after RYGB decreased significantly with the increase in surgeon RYGB volume (cases performed annually).

Bariatric surgery: what is the effect on type 2 diabetes?

Type 2 diabetes mellitus (T2DM) is a costly chronic disease that is associated with increased morbidity and mortality. Despite the development of numerous pharmacological agents, diet and exercise programs, and behavior-modification protocols, bariatric surgery remains the most effective tool for the durable reversal of T2DM. This review discusses the known effects of bariatric surgery on T2DM, with a particular focus on Roux-en-Y gastric bypass.

Weight and type 2 diabetes after bariatric surgery: systematic review and meta-analysis

BACKGROUND

The prevalence of obesity-induced type 2 diabetes mellitus is increasing worldwide. The objective of this review and meta-analysis is to determine the impact of bariatric surgery on type 2 diabetes in association with the procedure performed and the weight reduction achieved.

METHODS

The review includes all articles published in English from January 1, 1990, to April 30, 2006.

RESULTS

The dataset includes 621 studies with 888 treatment arms and 135,246 patients; 103 treatment arms with 3188 patients reported on resolution of diabetes, that is, the resolution of the clinical and laboratory manifestations of type 2 diabetes. Nineteen studies with 43 treatment arms and 11,175 patients reported both weight loss and diabetes resolution separately for the 4070 diabetic patients in these studies. At baseline, the mean age was 40.2 years, body mass index was 47.9 kg/m2, 80% were female, and 10.5% had previous bariatric procedures. Meta-analysis of weight loss overall was 38.5 kg or 55.9% excess body weight loss. Overall, 78.1% of diabetic patients had complete resolution, and diabetes was improved or resolved in 86.6% of patients. Weight loss and diabetes resolution were greatest for patients undergoing biliopancreatic diversion/duodenal switch, followed by gastric bypass, and least for banding procedures. Insulin levels declined significantly postoperatively, as did hemoglobin A1c and fasting glucose values. Weight and diabetes parameters showed little difference at less than 2 years and at 2 years or more.

CONCLUSION

The clinical and laboratory manifestations of type 2 diabetes are resolved or improved in the greater majority of patients after bariatric surgery; these responses are more pronounced in procedures associated with a greater percentage of excess body weight loss and is maintained for 2 years or more.

Expanded Occupational Safety and Health Administration 300 log as metric for bariatric patient-handling staff injuries

BACKGROUND

Mobilization of morbidly obese patients poses significant physical challenges to healthcare providers. The purpose of this study was to examine the staff injuries associated with the patient handling of the obese, to describe a process for identifying injuries associated with their mobilization, and to report on the need for safer bariatric patient handling.

METHODS

We performed our study at a 761-bed, level 1 trauma center affiliated with a U.S. medical school. The hospital's Occupational Safety and Health Administration (OSHA) 300 log was expanded to the "E-OSHA 300 log" to specifically identify injuries the staff attributed to bariatric patient handling. The 2007 E-OSHA 300 log was analyzed to identify and describe the frequency, severity, and nature of bariatric versus nonbariatric patient handling injuries.

RESULTS

The analyses revealed that during 2007, although patients with a body mass index of > or =35 kg/m(2) constituted <10% of our patient population, 29.8% of staff injuries related to patient handling were linked to working with a bariatric patient. Bariatric patient handling accounted for 27.9% of all lost workdays and 37.2% of all restricted workdays associated with patient handling. Registered nurses and nursing assistants accounted for 80% of the injuries related to bariatric patient handling. Turning and repositioning the patient in bed accounted for 31% of the injuries incurred. The E-OSHA 300 log narratives revealed that staff injuries associated with obese and nonobese patient handling were usually performed using biomechanics and not equipment.

CONCLUSION

Manual mobilization of morbidly obese patients increases the risk of caregiver injury. A tracking indicator on the OSHA 300 logs for staff injury linked to a bariatric patient would provide the ability to compare obese and nonobese patient handling injuries. The E-OSHA 300 log provides a method to identify the frequency, severity, and nature of caregiver injury during mobilization of the obese. Understanding the heightened risk of injury associated with manual bariatric patient handling should help healthcare institutions identify deficiencies in their current injury prevention program and focus resources more precisely for safer, systems-based bariatric patient-handling solutions. Effective patient handling systems should also reduce the aura of fear that might be present in some caregivers when mobilizing a bariatric patient.

Mechanism for improved insulin sensitivity after gastric bypass surgery

CONTEXT

Surgical treatments of obesity have been shown to induce rapid and prolonged improvements in insulin sensitivity.

OBJECTIVE

The aim of the study was to investigate the effects of gastric bypass surgery and the mechanisms that explain the improvement in insulin sensitivity.

DESIGN

We performed a cross-sectional, nonrandomized, controlled study.

SETTING

This study was conducted jointly between the Departments of Exercise Science and Physiology at East Carolina University in Greenville, North Carolina.

SUBJECTS

Subjects were recruited into four groups: 1) lean [body mass index (BMI) < 25 kg/m(2); n = 93]; 2) weight-matched (BMI = 25 to 35 kg/m(2); n = 310); 3) morbidly obese (BMI > 35 kg/m(2); n = 43); and 4) postsurgery patients (BMI approximately 30 kg/m(2); n = 40). Postsurgery patients were weight stable 1 yr after surgery.

MAIN OUTCOME MEASURES

Whole-body insulin sensitivity, muscle glucose transport, and muscle insulin signaling were assessed.

RESULTS

Postsurgery subjects had insulin sensitivity index values that were similar to the lean and higher than morbidly obese and weight-matched control subjects. Glucose transport was higher in the postsurgery vs. morbidly obese and weight-matched groups. IRS1-pSer(312) in the postsurgery group was lower than morbidly obese and weight-matched groups. Inhibitor kappaBalpha was higher in the postsurgery vs. the morbidly obese and weight-matched controls, indicating reduced inhibitor of kappaB kinase beta activity.

CONCLUSIONS

Insulin sensitivity and glucose transport are greater in the postsurgery patients than predicted from the weight-matched group, suggesting that improved insulin sensitivity after bypass is due to something other than, or in addition to, weight loss. Improved insulin sensitivity is related to reduced inhibitor of kappaB kinase beta activity and enhanced insulin signaling in muscle.

Bariatric surgery: risks and rewards

CONTEXT

Over 23 million Americans are afflicted with severe obesity, i.e. their body mass index (in kilograms per square meter) values exceed 35. Of even greater concern is the association of the adiposity with comorbidities such as diabetes, hypertension, cardiopulmonary failure, asthma, pseudotumor cerebri, infertility, and crippling arthritis.

OBJECTIVE

Diets, exercise, behavioral modification, and drugs are not effective in these individuals. This article examines the effect of surgery on the control of the weight and the comorbidities, as well as the safety of these operations.

INTERVENTIONS

Although the article focuses on the outcomes of the three most commonly performed operations, i.e. adjustable gastric banding, the gastric bypass, and the biliopancreatic bypass with duodenal switch, it aims for perspective with the inclusion of abandoned and current investigational procedures, a review of the complications, and an emphasis on the appropriate selection of patients. POSITIONS: Ample evidence, including controlled randomized studies, now document that bariatric surgery produces durable weight loss exceeding 100 lb (46 kg), full and long-term remission of type 2 diabetes in over 80% with salutary effects on the other comorbidities as well with significant reductions in all-cause mortality. Although the severely obese present with serious surgical risks, bariatric surgery is performed safely with a 0.35% 90-d mortality in Centers of Excellence throughout the United States-similar to the complication rates after cholecystectomy.

CONCLUSIONS

Until better approaches become available, bariatric surgery is the therapy of choice for patients with severe obesity.

Expression of genes regulating malonyl-CoA in human skeletal muscle

In humans and animal models, increased intramuscular lipid (IML) stores have been implicated in insulin resistance. Malonyl-CoA plays a critical role in cellular lipid metabolism both by serving as a precursor in the synthesis of lipids and by inhibiting lipid oxidation. In muscle, Malonyl-CoA acts primarily as a negative allosteric regulator of carnitine palmitoyl transferase-1 (CPT1) activity, thereby blocking the transport of long chain fatty acyl CoAs into the mitochondria for oxidation. In muscle, increased malonyl-CoA, decreased muscle CPT1 activity, and increased IML have all been reported in obesity. In order to determine whether malonyl-CoA synthesis might be under transcriptional as well as biochemical regulation, we measured mRNA content of several key genes that contribute to the cellular metabolism of malonyl-CoA in muscle biopsies from lean to morbidly obese subjects. Employing quantitative real-time PCR, we determined that expression of mitochondrial acetyl-CoA carboxylase 2 (ACC2) was increased by 50% with obesity (P < 0.05). In both lean and obese subjects, expression of mitochondrial ACC2 was 20-fold greater than that of cytoplasmic ACC1, consistent with their hypothesized roles in synthesizing malonyl-CoA from acetyl-CoA for CPT1 regulation and lipogenesis, respectively. In addition, in both lean and obese subjects, expression of malonyl-CoA decarboxylase was approximately 40-fold greater than fatty acid synthase, consistent with degradation, rather than lipogenesis, being the primary fate of malonyl-CoA in human muscle. No other genes showed signs of increased mRNA content with obesity, suggesting that there may be selective transcriptional regulation of malonyl-CoA metabolism in human obesity.

Safety and efficacy of bariatric surgery: Longitudinal Assessment of Bariatric Surgery

BACKGROUND

Obesity is a leading health concern in the United States. Because traditional treatment approaches for weight loss are generally unsuccessful in the long term, bariatric surgical procedures are increasingly being performed to treat extreme obesity. To facilitate research in this field, the National Institute of Diabetes and Digestive and Kidney Diseases responded to this knowledge gap by establishing the Longitudinal Assessment of Bariatric Surgery (LABS) consortium.

METHODS

A competitive National Institute of Diabetes and Digestive and Kidney Diseases grant process resulted in the creation of a group of investigators with expertise in bariatric surgery, internal medicine, endocrinology, behavioral science, outcomes research, epidemiology, biostatistics, and other relevant fields. These investigators have worked closely to plan, develop, and conduct the LABS study. The LABS consortium protocol is a prospective, multicenter observational cohort study of consecutive patients undergoing bariatric surgery at 6 clinical centers. LABS includes an extensive database of information systematically collected preoperatively, at surgery, perioperatively during the 30-day postoperative period, and longer term.

RESULTS

The LABS study has been organized into 3 phases. LABS-1 will include all patients > or =18 years of age who have undergone bariatric surgery by LABS-certified surgeons with the goal to evaluate the short-term safety of bariatric surgery. LABS-2, a subset of approximately 2400 LABS-1 patients, will evaluate the relationship of patient and surgical characteristics to the longer term safety and efficacy of bariatric surgery. LABS-3 will involve a subset of LABS-2 subjects who will undergo detailed studies of mechanisms involved in weight change. The rationale, goals, and approach to study bariatric surgery are detailed in this report, along with a description of the outcomes, measures, and hypotheses used in LABS-1 and -2.

CONCLUSION

The goal of the LABS consortium is to accelerate clinical research and understanding of extreme obesity and its complications by evaluating the risks and benefits of bariatric surgery. LABS investigators use standardized definitions, high-fidelity data collection, and validated instruments to enhance the ability of clinicians to provide meaningful evidence-based recommendations for patient evaluation, selection for surgery, and follow-up care.

Body Mass Index and Outcomes in Critically Injured Blunt Trauma Patients: Weighing the Impact

BACKGROUND

The influence of increased body mass index (BMI) on morbidity and mortality in critically injured trauma patients has been studied, with conflicting results. The objective of this study was to investigate the relationship between stratified BMI and outcomes in blunt injured patients.

STUDY DESIGN

Consecutive adult trauma patients from July 2001 to November 2005 with Injury Severity Score (ISS) > or = 16 and blunt mechanism were evaluated using the National Trauma Registry of the American College of Surgeons. Demographics, injury severity, hospital course, complications, and mortality were compared among standard BMI strata. Logistic regression was used to determine odds ratios (OR) with 95% confidence intervals and evaluate BMI as an independent risk factor for morbidity and mortality. Statistical significance was set at p < 0.05.

RESULTS

The study group consisted of 1,543 patients. Controlling for age, gender, Injury Severity Score, and Revised Trauma Score, and using BMI 18.5 to 24.9 kg/m(2) as the reference category, morbid obesity (BMI> or =40 kg/m(2)) was associated with acute respiratory distress syndrome (OR 3.675, 95% CI, 1.237 to 10.916), acute respiratory failure (OR 2.793, 95% CI, 1.633 to 4.778), acute renal failure (OR 13.506, 2.388 to 76.385), multisystem organ failure (OR 2.639, 95% CI, 1.085 to 6.421), pneumonia (OR 2.487, 95% CI, 1.483 to 4.302), urinary tract infection (OR 2.332, 95% CI, 1.229 to 4.427), deep venous thrombosis (OR 4.112, 95% CI, 1.253 to 13.496), and decubitus ulcer (OR 2.841, 95% CI, 1.382 to 5.841). Morbid obesity was not associated with increased mortality (OR 0.810, 95% CI, 0.353 to 1.856).

CONCLUSIONS

This is the largest study to date evaluating the relationship between BMI and outcomes in critically injured trauma patients. Increasing BMI increases morbidity while having no proved influence on mortality.

The ASBS Bariatric Surgery Centers of Excellence program: a blueprint for quality improvement

BACKGROUND

Variations in the techniques of bariatric surgery, coupled with the lack of a common database, has led to variable and, sometimes negative, outcomes from bariatric surgery. Thus, in November 2003, the American Society for Bariatric Surgery established Surgical Review Corporation (SRC) as an independent nonprofit entity for quality control of bariatric surgery and as a resource for data collection and analysis.

METHODS

In November 2003, the leadership of the American Society for Bariatric Surgery founded SRC as an independent nonprofit entity for quality control of bariatric surgery and as resource for research. A national set of standards for the Bariatric Surgery Centers of Excellence program was developed using a meta-analysis of the relevant published English language data, a consensus conference at Georgetown University, and participation by stakeholders from industry, third-party payors, and malpractice carriers. A software program was developed to provide uniformity in data collection and ease of analysis.

RESULTS

SRC developed standards that have been accepted by the bariatric surgical community and put in place. A system was developed for the designation of two levels for the centers, provisional and full. The growth of the Centers of Excellence program has been rapid. At present, 135 hospitals and 265 surgeons have achieved full approval. The centers for Medicare and Medicaid Services have recognized the program. On the basis of the reports of 55,567 patients from the first 176 applicants for full approval and confirmed by SRC during site inspections, the 90-day operative mortality rate was 0.35%.

CONCLUSIONS

The first phase of development has gone well. Future steps include the development of a network of bariatric physicians and the development of a consortium for research.

Endothelial nitric oxide synthase content in adipose tissue from obese and lean African American and white American women

It has been demonstrated that the enzyme endothelial nitric oxide synthase (eNOS) is present in adipose tissue, resulting in nitric oxide production and subsequent inhibition of lipolysis. A higher eNOS content has also been reported in the subcutaneous abdominal adipose tissue of obese than in that of lean white men. Furthermore, a lower lipolytic rate in obese than in lean women and a lower lipolytic rate in African American (AA) than in white American (WA) women have been demonstrated. The purpose of this study was to determine if eNOS protein content is higher in the subcutaneous and omental adipose tissues of obese than in those of lean women and if eNOS protein content is higher in the subcutaneous and omental adipose tissues of AA than in those of WA women. Whole tissue homogenates were prepared from frozen omental and subcutaneous adipose tissue samples obtained from lean and obese and AA and WA elective abdominal surgery patients and were analyzed for eNOS protein content using enzyme-linked immunosorbent assay. The adipose tissue eNOS protein content was approximately 40% higher in obese than in lean individuals (omental, 326.9 +/- 40.5 pg/mL lean and 445.3 +/- 38.0 pg/mL obese; subcutaneous, 246.8 +/- 20.8 pg/mL lean and 343.1 +/- 19.0 pg/mL obese; P < .05). There was no difference between the races for eNOS protein content in omental adipose tissue. In subcutaneous adipose tissue, there was a higher eNOS content in obese (417.1 +/- 78.9 pg/mg total protein) than in lean (216.7 +/- 29.9 pg/mg total protein) (P < .05) WA women, but there was no difference in subcutaneous adipose eNOS content between obese and lean AA women (250.7 +/- 47.4 and 294.1 +/- 42.2 pg/mg total protein, respectively). The higher eNOS content in the adipose tissue of obese than in that of lean WA women in the fasted state may contribute to the reduced lipolytic activity in WA women; however, eNOS protein content probably does not contribute to differences in lipolytic rates between AA and WA women.

Quality Assurance in Bariatric Surgery

Quality assurance is a function that exists in manufacturing,engineering, and the service industry. Bariatric surgery is an undertaking with a special form of consumer product and service. In this day of limited resources and significant value exchanges among stakeholders (ie, patients, surgeons, third-party payers),the goal of the bariatric community is to deliver quality outcomes with safety, efficacy, and efficiency. The American Society for Bariatric Surgery and the Surgical Review Corporation, in conjunction with the bariatric community, will use quality assurance methods to produce quality outcomes that will satisfy the value exchanges of all stakeholders.

Suppression of hepatic cholesteryl ester transfer protein expression in obese humans with the development of type 2 diabetes mellitus

Cholesteryl ester transfer protein (CETP) is a plasma enzyme that can modulate the profile of lipoproteins and is thus considered: 1) a mediator of vascular disease; and 2) a therapeutic target for vascular disease. In the present study, we pursued a better understanding of the effect of type 2 diabetes on the expression of CETP in obese patients. Obesity was accompanied by a 20% elevation in plasma CETP that was eliminated with the development of diabetes. These differences were observed for both men and women and were due to variations in the amount of CETP protein in the plasma. The mRNA and protein of both the full-length (CETPFL) and alternatively spliced (CETPDelta9) forms of CETP were lower in the liver, but not in either sc or omental adipose tissue depots, of diabetic obese subjects. Sterol response element binding proteins 1 and 2 were also lower in liver homogenates, suggesting that these transcription factors may mediate the effects of type 2 diabetes on hepatic CETP expression. Thus, the suppressive effects of type 2 diabetes in obese subjects are observed in both men and women and may be due, at least in part, to a suppression of hepatic CETP expression.

Epidemiology of obesity in the United States

The challenges of the epidemic are not limited to concerns about bulk and weight. The disabilities caused by obesity are physiologic and psychosocial. The increased waist to hip girth is associated with increased risk of cardiovascular disease, hyperlipidemia, hypertension, and diabetes. Obesity also has been related directly to increased risk of sleep apnea, cancer, gallbladder disease, musculoskeletal disorders, severe pancreatitis, bacterial panniculitis, diverticulitis, infertility, urinary incontinence, and idiopathic intracranial hypertension. The psychosocial factors and quality of life in the obese population also have been documented. Although there is some debate, the obese have been found to be twice as likely to suffer from anxiety, impaired social interaction,and depression when compared with the nonobese population. Although advances in obesity surgery have resulted in long-term, lasting treatment of this disease and some of its comorbidities (ie, diabetes, hypertension, sleep apnea), There is a pressing need to develop a comprehensive medical and nutrition plan to reduce the prevalence of this newly identified disease state. Some draw parallels to tobacco and the morbidity and mortality associated with its use. Perhaps there are similarities in these two epidemics. Both start with education of the population as to the morbidities and mortality associated with the disease. As with tobacco, this education is especially important for youth. Without a plan of education to promote nutrition and increased physical activity, and continued research into the causes of obesity, the prevalence of obesity will continue to rise in the United States.

Muscle insulin receptor concentrations in obese patients post bariatric surgery: relationship to hyperinsulinemia

OBJECTIVE

Obesity results in insulin resistance. Bariatric surgery for obese individuals induces weight loss, improves insulin sensitivity, and lowers insulin levels. We investigated the mechanisms of this improvement.

DESIGN

Insulin receptor (IR) content, IR signaling, and adiponectin levels were measured in nine morbidly obese subjects before and after bariatric surgery.

SUBJECTS

Seven female and two male, average age 44+/-2y, BMI >40 kg/m(2) and/or at least 100 lbs over ideal body weight, undergoing elective bariatric surgery.

MEASUREMENTS

Before surgery BMI, fasting plasma glucose, adiponectin, and insulin levels were measured. A fasting muscle biopsy was obtained from the vastus lateralis for IR concentration and autophosphorylation activity measurements. These procedures were repeated 1 y after surgery.

RESULTS

At 1 y after surgery, the subjects had lost an average of 48.3+/-5.6 kg (P<0.001), insulin sensitivity had significantly increased as determined by the minimal model (SI 0.72+/-0.18 vs 3.86+/-1.43, P<0.05), and IR content had increased two-fold in muscle (2.1+/-0.4 vs 4.3+/-0.7 ng/mg protein, P<0.01). The increase in IR content was related to fasting insulin levels. In the subjects with the lowest IR function, there was also an increase in IR function. Plasma adiponectin increased by 40% following weight loss (7.4+/-1.6 pre vs 10.3+/-1.3 mg/ml post, P<0.05). There was no significant change in muscle content of the IR inhibitor, PC-1.

CONCLUSION

Increased IR content, most likely regulated by insulin levels, may be one contributor to the increased insulin sensitivity that occurs when morbidly obese patients undergo bariatric surgery.

Ethnic differences in adiponectin levels

Adiponectin levels were measured in African American and Caucasian women of varying body mass index (BMI). Plasma adiponectin levels were compared and the relationship between adiponectin and insulin sensitivity was assessed. Adiponectin levels were similar in the Caucasian obese (7.0 +/- 0.8 microg/mL), African American obese (7.3 +/- 3.5 microg/mL), and African American non-obese women (7.1 +/- 1.2 microg/mL), but were significantly higher in Caucasian non-obese women (12.2 +/- 1.4 microg/mL). Correlational analyses demonstrated that BMI, insulin, and homeostasis model assessment (HOMA) correlated significantly with adiponectin levels in only the Caucasian women. These results provide support for the notion that what applies to other ethnic populations might not apply to the African American population, and that the association between adiponectin and insulin sensitivity needs to be clarified in the African American population.

Current status and future directions of geriatric general surgery

As the population ages and requires more health care, a significant part of this is in surgical services. As elderly patients account for a growing proportion of most surgeons' practices, it is apparent that this patient group has special requirements, differences in outcomes, and different physiology from other patients encountered in the typical surgical practice. The greater frequency of emergency operations in older than in younger patients, with higher morbidity and mortality rates, compounds these differences. This paper reviews the current status of general surgery in older patients with a special focus on emergency procedures, major abdominal surgery, biliary disease, endocrine disease, and breast cancer. Each of these areas is a source of considerable interest to general surgeons.

Appropriateness of quality indicators for older patients with advanced dementia and poor prognosis

OBJECTIVES

To evaluate the applicability of process-of-care quality indicators (QIs) to vulnerable elders and to measure the effect of excluding indicators based on patients' preferences and for advanced dementia and poor prognosis.

DESIGN

The Assessing Care of Vulnerable Elders (ACOVE) project employed 203 QIs for care of 22 conditions (including six geriatric syndromes and 11 age-associated diseases) for community-based persons aged 65 and older at increased risk of functional decline or death. Relevant QIs were excluded for persons deciding against hospitalization or surgery. A 12-member clinical committee (CC) of geriatric experts rated whether each QI should be applied in scoring quality of care for persons with advanced dementia (AdvDem) or poor prognosis (PoorProg). Using content analysis, CC ratings were formulated into a model of QI exclusion. Quality scores with and without excluded QIs were compared.

SETTING

Enrollees in two senior managed care plans, one in the northeast United States and the other in the southwest.

PARTICIPANTS

CC members evaluated applicability of QIs. QIs were applied to 372 vulnerable elders in two senior managed care plans.

MEASUREMENTS

Frequency and type of QIs excluded and the effect of excluding QIs on quality of care scores.

RESULTS

Of the 203 QIs, a patient's preference against hospitalization or surgery excluded 10 and eight QIs, respectively. The CC voted to exclude 81.5 QIs (40%) for patients with AdvDem and 70 QIs (34%) for patients with PoorProg. Content analysis of the CC votes revealed that QIs aimed at care coordination, safety or prevention of decline, or short-term clinical improvement or prevention with nonburdensome interventions were usually voted for inclusion (90% and 98% included for AdvDem and PoorProg, respectively), but QIs directed at long-term benefit or requiring interventions of moderate to heavy burden were usually excluded (16% and 19% included, respectively). About half of QIs aimed at age-associated diseases were voted for exclusion, whereas fewer than one-quarter of QIs for geriatric syndromes were excluded. Thirty-nine patients (10%) in our field trial held preferences or had clinical conditions that would have excluded 68 QIs. This accounted for 5% of all QIs triggered by these 39 patients and 0.6% of QIs overall. The quality score without exclusion was 0.57 and with exclusion was 0.58 (P =.89).

CONCLUSION

Caution is required in applying QIs to vulnerable elders. QIs for geriatric syndromes are more likely to be applicable to these individuals than are QIs for age-associated diseases. The objectives of care, intervention burdens, and interval before anticipated benefit affect QI applicability. At least for patients with AdvDem and PoorProg, identification of applicable or inapplicable QIs is feasible. In a community-based sample of vulnerable elders, few QIs are excluded.

Fatty acid oxidation by skeletal muscle homogenates from morbidly obese black and white American women

The purpose of this study was to determine if there were differences in the capacity of skeletal muscle from morbidly obese Black and White American women to oxidize fatty acids. The oxidation rates of (14)C-palmitate, (14)C-palmitoyl-CoA, and (14)C-palmitoyl-carnitine were measured in whole homogenates of rectus abdominus from Black and White women who were similar in age and body mass index (BMI). The activities of muscle citrate synthase (CS), beta-hydroxy acyl-CoA dehydrogenase (beta-HAD), and mitochondrial and microsomal acyl-CoA synthetase (ACS) were measured in the 2 groups. The results showed that the rate of (14)C-palmitate oxidation by muscle of Black women was 25% that of Whites (8.7 +/- 1.5 v 34.4 +/- 6.8 nmol (14)CO(2) produced/gram tissue wet weight/ hour; P <.05), but the rates of (14)C-palmitoyl-CoA and (14)C-palmitoyl-carnitine oxidation were not different in the 2 groups. No differences were found in the activities of CS or beta-HAD. However, the activities of both mitochondrial and microsomal ACS were lower in the Black women than the Whites (mitochondrial ACS 25.1 +/- 3.9 v 36.4 +/- 5.0 nmol/mg protein/min; P <.05; microsomal ACS 6.2 +/- 0.5 v 8.5 +/- 0.5; nmol/mg protein/min; P <.005). The lower rate of palmitate oxidation, and the lack of differences in the rates of palmitoyl-CoA and palmitoyl-carnitine oxidation indicate that there is a defect in the activation of the fatty acid in the muscle of the Black women. This was confirmed by the decrease in mitochondrial ACS activity in the Black women. The decreased fatty acid oxidation by skeletal muscle of obese Black women could result in shunting these fuels from muscle to adipose tissue for storage, which may contribute to the maintenance of obesity in the Black women.

Effect of weight loss on muscle lipid content in morbidly obese subjects

The purpose of this study was to test the hypothesis that weight loss results in a reduction in intramuscular lipid (IMCL) content that is concomitant with enhanced insulin action. Muscle biopsies were obtained from morbidly obese individuals [body mass index (BMI) 52.2 +/- 2.5 kg/m(2); n = 6] before and after gastric bypass surgery, an intervention that improves insulin action. With intervention, there was a 47% reduction (P < 0.01) in BMI and a 93% decrease in homeostasis model assessment, or HOMA (7.0 +/- 1.9 vs. 0.5 +/- 0.1). Histochemically determined IMCL content decreased (P < 0.05) by approximately 30%. In relation to fiber type, IMCL was significantly higher in type I vs. type II fibers. In both fiber types, there were reductions in IMCL and trends for muscle atrophy. Despite these two negating factors, the IMCL-to-fiber area ratio still decreased by approximately 44% with weight loss. In conclusion, despite differing initial levels and possible atrophy, weight loss appears to decrease IMCL deposition to a similar relative extent in type I and II muscle fibers. This reduction in intramuscular triglyceride may contribute to enhanced insulin action seen with weight loss.

Skeletal muscle lipid metabolism with obesity

The objectives of this study were to 1). examine skeletal muscle fatty acid oxidation in individuals with varying degrees of adiposity and 2). determine the relationship between skeletal muscle fatty acid oxidation and the accumulation of long-chain fatty acyl-CoAs. Muscle was obtained from normal-weight [n = 8; body mass index (BMI) 23.8 +/- 0.58 kg/m(2)], overweight/obese (n = 8; BMI 30.2 +/- 0.81 kg/m(2)), and extremely obese (n = 8; BMI 53.8 +/- 3.5 kg/m(2)) females undergoing abdominal surgery. Skeletal muscle fatty acid oxidation was assessed in intact muscle strips. Long-chain fatty acyl-CoA concentrations were measured in a separate portion of the same muscle tissue in which fatty acid oxidation was determined. Palmitate oxidation was 58 and 83% lower in skeletal muscle from extremely obese (44.9 +/- 5.2 nmol x g(-1) x h(-1)) patients compared with normal-weight (71.0 +/- 5.0 nmol x g(-1) x h(-1)) and overweight/obese (82.2 +/- 8.7 nmol x g(-1) x h(-1)) patients, respectively. Palmitate oxidation was negatively (R = -0.44, P = 0.003) associated with BMI. Long-chain fatty acyl-CoA content was higher in both the overweight/obese and extremely obese patients compared with normal-weight patients, despite significantly lower fatty acid oxidation only in the extremely obese. No associations were observed between long-chain fatty acyl-CoA content and palmitate oxidation. These data suggest that there is a defect in skeletal muscle fatty acid oxidation with extreme obesity but not overweight/obesity and that the accumulation of intramyocellular long-chain fatty acyl-CoAs is not solely a result of reduced fatty acid oxidation.

Effect of weight loss on insulin sensitivity and intramuscular long-chain fatty acyl-CoAs in morbidly obese subjects

Increases in intramyocellular long-chain fatty acyl-CoAs (LCACoA) have been implicated in the pathogenesis of insulin resistance in skeletal muscle. To test this hypothesis, we measured muscle (vastus lateralis) LCACoA content and insulin action in morbidly obese patients (n = 11) before and after weight loss (gastric bypass surgery). The intervention produced significant weight loss (142.3 +/- 6.8 vs. 79.6 +/- 4.1 kg for before versus after surgery, respectively). Fasting insulin decreased by approximately 84% (23.3 +/- 3.8 vs. 3.8 +/- 0.5 mU/ml), and insulin sensitivity, as determined by minimal model, increased by approximately 360% (1.2 +/- 0.3 vs. 4.1 +/- 0.5 min(-1). [ micro U/kg(-1)]) indicating enhanced insulin action. Muscle palmityl CoA (16:0; 0.54 +/- 0.08 vs. 0.35 +/- 0.04 nmol/g wet wt) concentration decreased by approximately 35% (P < 0.05) with weight loss, whereas stearate CoA (18:0; -17%; 0.65 +/- 0.05 vs. 0.54 +/- 0.03 nmol/g wet wt) and linoleate CoA (18:2; -30%; 2.47 +/- 0.27 vs. 1.66 +/- 0.19 nmol/g wet wt) were also reduced (P < 0.05). There were no statistically significant declines in muscle palmitoleate CoA (16:1), oleate CoA (18:1), or total LCACoA content. These data suggest that a reduction in intramuscular LCACoA content may be responsible, at least in part, for the enhanced insulin action observed with weight loss in obese individuals.

Adiponectin is not altered with exercise training despite enhanced insulin action

Adiponectin is an adipocytokine that is hypothesized to be involved in the regulation of insulin action. The purpose of the present investigation was to determine whether plasma adiponectin is altered in conjunction with enhanced insulin action with exercise training. An insulin sensitivity index (S(I)) and fasting levels of glucose, insulin, and adiponectin were assessed before and after 6 mo of exercise training (4 days/wk for approximately 45 min at 65-80% peak O(2) consumption) with no loss of body mass (PRE, 91.9 +/- 3.8 kg vs. POST, 91.6 +/- 3.9 kg) or fat mass (PRE, 26.5 +/- 1.8 kg vs. POST, 26.7 +/- 2.2 kg). Insulin action significantly (P < 0.05) improved with exercise training (S(I) +98%); however, plasma adiponectin concentration did not change (PRE, 6.3 +/- 1.5 microg/ml vs. POST, 6.6 +/- 1.8 microg/ml). In contrast, in a separate group of subjects examined before and after weight loss, there was a substantial increase in adiponectin (+281%), which was accompanied by enhanced insulin action (S(I), +432%). These data suggest that adiponectin is not a contributory factor to the exercise-related improvements in insulin sensitivity.