Bariatric Surgery for Adolescents with Type 2 Diabetes: an Emerging Therapeutic Strategy.

PURPOSE OF REVIEW: Type 2 diabetes (T2D) is a growing public health problem in youth, but conventional treatments are often insufficient to treat this disease and its comorbidities. We review evidence supporting an emerging role for bariatric surgery as a treatment for adolescent T2D. RECENT FINDINGS: Paralleling what has been seen in adult patients, bariatric surgery dramatically improves glycemic control in patients with T2D. In fact, remission of T2D has been observed in as many as 95-100% of adolescents with diabetes after bariatric surgery, particularly vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) surgery. This striking outcome may be due to both weight-dependent- and weight-independent factors, and recent studies suggest that T2D-related comorbidities may also improve after surgery. Bariatric surgery including RYGB and VSG is a powerful therapeutic option for obese adolescents with T2D. Benefits must be weighed against risk for postoperative complications such as nutritional deficiencies, but earlier surgical intervention might lead to more complete metabolic remission in obese patients with T2D.

Three-decade metabolic outcome of neonatal gastrectomy and early Roux-en-Y.

Little information is available about long-term outcomes of major gastric surgery when performed very early in life and adverse consequences in growing children might be expected. In this case, gastrectomy with Roux-en-Y esophagojejunostomy was performed in early childhood. Despite stomach loss, growth velocity paralleled the third percentile for age during development. Maintained on a daily multivitamin and monthly B12 injections, no overt nutritional deficiencies were detected in adulthood. However, dual energy X-ray absorptiometry scan at age 31 revealed that the patient had abnormally low bone mineral density. This case study demonstrates that even after gastrectomy and reconstruction early in life, linear growth can be achieved. However, bone density can be adversely affected, even in the face of normal serum calcium and vitamin D levels.

The effect of vertical sleeve gastrectomy on food choice in rats.

OBJECTIVE: Diets high in fat are implicated in the development and maintenance of obesity, and obese individuals display greater preferences for high-fat foods than do their lean counterparts. Weight-reduction bariatric surgery is associated with changes in food choice. In particular, after Roux-en-Y gastric bypass (RYGB), humans and rodents select or prefer foods that are lower in fat content. We asked whether a bariatric surgical procedure limited to the stomach, vertical sleeve gastrectomy (VSG), causes a similar reduction of fat intake/preference. RESEARCH DESIGN AND METHODS: Rats received VSG or Sham surgery or remained surgically naïve, and were assessed for food preference using three diet-choice paradigms. Using progressive-ratio (PR) and conditioned taste aversion paradigms, we further asked whether surgically induced changes in food choice are secondary to changes in the reward value of food and/or to the formation of a food aversion. Finally, food choice was compared between VSG- and RYGB-operated rats. RESULTS: VSG rats decreased their intake of dietary fat, and shifted their preference toward lower caloric-density foods. This change in food choice was not associated with changes in motivated responding on a PR schedule for either a fat or a carbohydrate food reinforcer. When VSG and RYGB were compared directly, both procedures caused comparable changes in food choice. The conditioned taste aversion paradigm revealed that VSG rats form an aversion to an intra-gastric oil administration whereas RYGB rats do not. CONCLUSIONS: VSG and RYGB, two anatomically distinct bariatric procedures, produce similar changes in food choice.

Bariatric surgery for adolescents.

Obesity is no longer just an adult disease. An increasing number of youth are overweight, defined as body mass index (BMI) at or greater than the 95th percentile for age (1). Between 2009 and 2010, 16.9% of children aged 2­19 yr were classified as overweight based on BMI (2), as compared with only 5% of children affected by obesity in 1976­1980 (3). This is a problem of enormous proportion from a public health standpoint, as without intervention these children will grow up to become overweight and obese adults. For an obese child, the risk of becoming an obese adult may be as high as 77%, compared with 7%for a child of healthy weight (4). Morbid obesity is a major risk factor for later complications such as cardiovascular disease, type 2 diabetes, obstructive sleep apnea (OSA), polycystic ovary syndrome (PCOS), and degenerative joint disease (4­10). Obesity is also an expensive problem: the US government spends $147 billion yearly on obesity-related healthcare costs (11). Thus, there is an urgent need to target obesity in the pediatric population, before the expensive and life-threatening consequences of obesity manifest. Unfortunately, the effectiveness of medical treatments for obesity is limited. Behaviorally based dietary and physical activity interventions offer little benefit for pediatric obesity, while pharmacologic therapy is also limited and carries low success rates and recidivism (12­14) (Table 1).

The anorectic effect of CNTF does not require action in leptin-responsive neurons.

Leptin resistance is a feature of obesity that poses a significant therapeutic challenge. Any treatment that is effective to reduce body weight in obese patients must overcome or circumvent leptin resistance, which promotes the maintenance of excess body fat in obese individuals. Ciliary neurotrophic factor (CNTF) is unique in its ability to reduce food intake and body weight in obese, leptin-resistant humans and rodents. Although attempts to use CNTF as an obesity therapy failed due to the development of neutralizing antibodies to the drug, efforts to understand mechanisms for CNTF's anorectic effects provide an opportunity to develop new drugs for leptin-resistant individuals. CNTF and leptin share several structural, anatomic, and signaling properties, but it is not understood whether or how the two cytokines might interact to affect energy balance. Here, we conditionally deleted the CNTF receptor (CNTFR) subunit, CNTFRα, in cells expressing leptin receptors. We found that CNTFR signaling in leptin-responsive neurons is not required for endogenous maintenance of energy balance and is not required for the anorectic response to exogenous administration of a CNTF agonist. These results indicate that despite anatomical overlap for CNTF and leptin action, CNTF appears to act within a distinct neuronal population to elicit its potent anorectic effect.

Central nervous system nutrient signaling: the regulation of energy balance and the future of dietary therapies.

The mammalian target of rapamycin (mTOR) pathway coordinates cell growth in response to nutrient availability. Increasing evidence points to a role for mTOR to also direct whole-body energy balance in response to micronutrient as well as hormonal cues. This positions mTOR as a key central integrator of acute and chronic changes in fuel status. Energy balance is affected by mTOR in several organ systems, including the hypothalamus, where the pathway can modulate feeding. We propose that a greater understanding of this nutrient-sensitive pathway may open the door to more intelligent, effective diet design based on the effects of micronutrients on specific signaling pathways.