The surgical approach to management of pediatric obesity: when to refer and what to expect

Gut Microbiota Markers in Obese Adolescent and Adult Patients: Age-Dependent Differential Patterns

Obesity levels, especially in children, have dramatically increased over the last few decades. Recently, several studies highlighted the involvement of gut microbiota in the pathophysiology of obesity. We investigated the composition of gut microbiota in obese adolescents and adults compared to age-matched normal weight (NW) volunteers in order to assemble age- and obesity-related microbiota profiles. The composition of gut microbiota was analyzed by 16S rRNA-based metagenomics. Ecological representations of microbial communities were computed, and univariate, multivariate, and correlation analyses performed on bacterial profiles. The prediction of metagenome functional content from 16S rRNA gene surveys was carried out. Ecological analyses revealed a dissimilarity among the subgroups, and resultant microbiota profiles differed between obese adolescents and adults. Using statistical analyses, we assigned, as microbial markers, Faecalibacterium prausnitzii and Actinomyces to the microbiota of obese adolescents, and Parabacteroides, Rikenellaceae, Bacteroides caccae, Barnesiellaceae, and Oscillospira to the microbiota of NW adolescents. The predicted metabolic profiles resulted different in adolescent groups. Particularly, biosynthesis of primary bile acid and steroid acids, metabolism of fructose, mannose, galactose, butanoate, and pentose phosphate and glycolysis/gluconeogenesis were for the majority associated to obese, while biosynthesis and metabolism of glycan, biosynthesis of secondary bile acid, metabolism of steroid hormone and lipoic acid were associated to NW adolescents. Our study revealed unique features of gut microbiota in terms of ecological patterns, microbial composition and metabolism in obese patients. The assignment of novel obesity bacterial markers may open avenues for the development of patient-tailored treatments dependent on age-related microbiota profiles.

Bariatric surgery in severely obese adolescents: a single-centre experience

BACKGROUND

Increasing numbers of severely obese young people undergo bariatric surgery in the USA with reports of substantial weight loss after 1 year. National Institute for Clinical Excellence 2006 suggests considering surgery for young people in 'exceptional circumstances'. We present six patients operated upon 2004-2012 at our centre in the UK.

CASE SERIES

Six patients (4 male) aged 14-16 years (mean age 15.10) underwent surgery. Mean preoperative body mass index (BMI) was 62.7 kg/m(2) and BMI SDS +4.4. Comorbidities included hypertension, insulin resistance, obstructive sleep apnoea, limited mobility, benign intracranial hypertension and psychosocial issues. All six patients had prior involvement with local lifestyle weight management services and had pharmacological intervention. Four laparoscopic gastric bypass procedures, one laparoscopic gastric banding (patient had a gastric balloon prior to band) and one laparoscopic sleeve gastrectomy were performed.

RESULTS

There were no major postoperative procedural complications (one patient had a port rotation). Mean percentage of weight loss, as a percentage of total body weight at 6 and 12 months, was 22 and 27%, respectively. Average absolute weight loss at current follow-up is 54 kg. Mean BMI at 12 months postprocedure was 46.5 kg/m(2)-a mean fall of 16.2 kg/m(2). Mean BMI SDS fell from +4.4 to +3.8 at 12 months and +3.1 at 2 years. Resolution of hypertension, improved school attendance and no progression to T2DM were the benefits noted.

CONCLUSIONS

Recent systematic reviews and meta-analyses suggest that bariatric surgery results in sustained and clinically significant weight loss in paediatric populations. The surgical option should continue to be exercised with extreme caution only in severely obese adolescents and done so in appropriate case results in positive outcomes.

Hypothalamic obesity in children

Hypothalamic obesity is an intractable form of obesity syndrome that was initially described in patients with hypothalamic tumours and surgical damage. However, this definition is now expanded to include obesity developing after a variety of insults, including intracranial infections, infiltrations, trauma, vascular problems and hydrocephalus, in addition to acquired or congenital functional defects in central energy homeostasis in children with the so-called common obesity. The pathogenetic mechanisms underlying hypothalamic obesity are complex and multifactorial. Weight gain results from damage to the ventromedial hypothalamus, which leads, variously, to hyperphagia, a low-resting metabolic rate; autonomic imbalance; growth hormone-, gonadotropins and thyroid-stimulating hormone deficiency; hypomobility; and insomnia. Hypothalamic obesity did not receive enough attention, as evidenced by rarity of studies in this group of patients. A satellite symposium was held during the European Congress of Obesity in May 2011, in Istanbul, Turkey, to discuss recent developments and concepts regarding pathophysiology and management of hypothalamic obesity in children. An international group of leading researchers presented certain aspects of the problem. This paper summarizes the highlights of this symposium. Understanding the central role of the hypothalamus in the regulation of feeding and energy metabolism will help us gain insights into the pathogenesis and management of common obesity.

Pediatric surgery and the human microbiome

Bold advances in the past decade have made it possible to carefully study the contributions of microbes to normal human development and to disease pathogenesis. The intestinal microbiota has been implicated in adult diseases ranging from obesity to cancer, but there have been relatively few investigations of bacteria in surgical diseases of infancy and childhood. In this review, we discuss how novel culture-independent approaches have been harnessed to profile microbes present within clinical specimens. Unique features of the pediatric microbiota and innovative approaches to manipulate the gut flora are also reviewed. Finally, we detail the contributions of gut microbes to 3 diseases relevant to pediatric surgeons: necrotizing enterocolitis, obesity, and inflammatory bowel disease. Current and future research regarding the pediatric microbiota is likely to translate to improved outcomes for infants and children with surgical diseases.

Effectiveness and cost-effectiveness of paediatric bariatric surgery: a systematic review

Strong evidence for successful and cost-effective obesity management strategies is still generally lacking, leading the medical profession to rely increasingly on surgical options to treat obesity in children and adolescents. We performed a systematic review to examine the effectiveness of surgical interventions to treat obese children and adolescents, and whether they are cost-effective. We searched PubMed, ISI Web of Science, Embase and the Cochrane Library to 6 September 2010, and hand-searched bibliographies. We included articles with English abstracts if they examined subjects ≤19 years of age, reported at least one postoperative weight loss measure and at least 1 year of postoperative follow-up. Thirty-seven relevant papers on bariatric surgery effectiveness in 831 children or adolescents were included, spanning 36 years. Thirteen studies examined gastric banding, with mean body mass index (BMI) reductions ranging from 8.5 to 43 kg m(-2) . Weight gain was reported in one case study. Eight papers examined Roux-en-Y gastric bypass, with mean BMI reductions ranging from 9 to 25 kg m(-2) . Fourteen publications studied other forms of bariatric surgery: sleeve gastrectomies, vertical banded gastroplasty, biliopancreatic diversion or a combination of procedures. Mean BMI reductions ranged from 9 to 24 kg m(-2) . Three surgery-related mortalities were reported, as was weight regain in several cases. The majority of studies reported resolution or improvement of comorbid conditions. A range of postoperative complications were identified across surgery types, including: ulcers, intestinal leakage, wound infection, anastomotic stricture, nutritional deficiencies, bowel obstruction, pulmonary embolism, disrupted staple lines, band slippage, psychological intolerance and repeated vomiting. Evidence on cost-effectiveness was limited to one Australian modelling project, which deemed laparoscopic adjustable gastric banding cost-effective for adolescents. Existing evidence - although based generally on underpowered, retrospective studies - suggests that bariatric surgery in older children results in significant weight loss and improvements in comorbidities and quality of life. However, postoperative complications, compliance and follow-up may be more problematic in adolescents than adults, and availability of long-term data on safety, effectiveness and cost-effectiveness remains largely unknown. Pending an improvement in the quality of available evidence, a cautious approach to child and adolescent bariatric surgery is warranted, and reversible techniques are advisable compared to approaches that permanently alter anatomy.