Type 2 diabetes: an epidemic disease in childhood

Control of postprandial hyperglycemia by oral administration of the sea anemone mucus-derived α-amylase inhibitor (magnificamide)

Diabetes mellitus is a serious threat to human health in both developed and developing countries. Optimal disease control requires the use of a diet and a combination of several medications, including oral hypoglycemic agents such as α-glucosidase inhibitors. Currently, the arsenal of available drugs is insufficient, which determines the relevance of studying new potent α-amylase inhibitors. We implemented the recombinant production of sea anemone derived α-amylase inhibitor magnificamide in Escherichia coli. Peptide was isolated by a combination of liquid chromatography techniques. Its folding and molecular weight was proved by 1H NMR and mass spectrometry. The Ki value of magnificamide against human pancreatic α-amylase is 3.1 nM according to Morrison equation for tight binding inhibitors. Our study of the thermodynamic characteristics of binding of magnificamide to human salivary and pancreatic α-amylases by isothermal titration calorimetry showed the presence of different binding mechanisms with Kd equal to 0.11 µM and 0.1 nM, respectively. Experiments in mice with streptozotocin-induced diabetes mimicking diabetes mellitus type 1 were used to study the efficiency of magnificamide against postprandial hyperglycemia. It was found that at a dose of 0.005 mg kg-1, magnificamide effectively blocks starch breakdown and prevents the development of postprandial hyperglycemia in T1D mice. Our results demonstrated the therapeutic potential of magnificamide for the control of postprandial hyperglycemia.

Magnificamide Is a New Effective Mammalian α-Amylase Inhibitor

Recombinant analogue of the sea anemone Heteractismagnifica peptide was obtained, and the kinetic parameters of its interaction with mammalian α-amylases were determined. Magnificamide inhibits α-amylases significantly stronger than the medical drug acarbose (Precose^TM or Glucobay^TM). Magnificamide is assumed to find application as a drug for prevention and treatment of metabolic disorders and type 2 diabetes mellitus.

Magnificamide, a β-Defensin-Like Peptide from the Mucus of the Sea Anemone Heteractis magnifica, Is a Strong Inhibitor of Mammalian α-Amylases

Sea anemones’ venom is rich in peptides acting on different biological targets, mainly on cytoplasmic membranes and ion channels. These animals are also a source of pancreatic α-amylase inhibitors, which have the ability to control the glucose level in the blood and can be used for the treatment of prediabetes and type 2 diabetes mellitus. Recently we have isolated and characterized magnificamide (44 aa, 4770 Da), the major α-amylase inhibitor of the sea anemone Heteractis magnifica mucus, which shares 84% sequence identity with helianthamide from Stichodactyla helianthus. Herein, we report some features in the action of a recombinant analog of magnificamide. The recombinant peptide inhibits porcine pancreatic and human saliva α-amylases with Ki’s equal to 0.17 ± 0.06 nM and 7.7 ± 1.5 nM, respectively, and does not show antimicrobial or channel modulating activities. We have concluded that the main function of magnificamide is the inhibition of α-amylases; therefore, its functionally active recombinant analog is a promising agent for further studies as a potential drug candidate for the treatment of the type 2 diabetes mellitus.

Trace Amines and Their Receptors

Trace amines are endogenous compounds classically regarded as comprising β-phenylethyalmine, p-tyramine, tryptamine, p-octopamine, and some of their metabolites. They are also abundant in common foodstuffs and can be produced and degraded by the constitutive microbiota. The ability to use trace amines has arisen at least twice during evolution, with distinct receptor families present in invertebrates and vertebrates. The term "trace amine" was coined to reflect the low tissue levels in mammals; however, invertebrates have relatively high levels where they function like mammalian adrenergic systems, involved in "fight-or-flight" responses. Vertebrates express a family of receptors termed trace amine-associated receptors (TAARs). Humans possess six functional isoforms (TAAR1, TAAR2, TAAR5, TAAR6, TAAR8, and TAAR9), whereas some fish species express over 100. With the exception of TAAR1, TAARs are expressed in olfactory epithelium neurons, where they detect diverse ethological signals including predators, spoiled food, migratory cues, and pheromones. Outside the olfactory system, TAAR1 is the most thoroughly studied and has both central and peripheral roles. In the brain, TAAR1 acts as a rheostat of dopaminergic, glutamatergic, and serotonergic neurotransmission and has been identified as a novel therapeutic target for schizophrenia, depression, and addiction. In the periphery, TAAR1 regulates nutrient-induced hormone secretion, suggesting its potential as a novel therapeutic target for diabetes and obesity. TAAR1 may also regulate immune responses by regulating leukocyte differentiation and activation. This article provides a comprehensive review of the current state of knowledge of the evolution, physiologic functions, pharmacology, molecular mechanisms, and therapeutic potential of trace amines and their receptors in vertebrates and invertebrates.

Effect of folic acid and metformin on insulin resistance and inflammatory factors of obese children and adolescents

Background:

Considering the increasing trend of obesity, especially in developing countries such as Iran, and the role of inflammatory factors and insulin resistance (IR) in the occurrence of obesity-related complications as well as the safety of some agents such as folic acid and metformin, this clinical trial was designed to investigate the effect of metformin and folic acid on inflammatory factors and IR among obese children.

Materials and Methods:

In this randomized, double-blind, controlled clinical trial study, sixty obese children aged 6–12 years were enrolled. Selected obese children were randomly allocated in two interventional (1 mg/daily folic acid or 1000 mg metformin for 8 weeks) groups. Biochemical measurements including homeostasis model assessment of IR (HOMA-IR), homocysteine (Hcy), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) were measured between and within the groups before and after trial.

Results:

In each group, thirty obese children were studied. The groups were age- and sex-matched. After folic acid and metformin administration, mean of Hcy, HOMA-IR, TNF-α, and IL-8 decreased significantly (P < 0.05). IL-6 decreased significantly after folic acid use (P < 0.05).

Conclusion:

The findings of this trial indicated that both metformin and folic acid could decrease IR and level of Hcy in obese children and adolescents. The effectiveness of metformin on IR was more significant than folic acid. Regarding the effectiveness of the two studied agents on inflammatory factors, it is suggested that the role of folic acid was superior to metformin. It is suggested that metformin is a proper agent for obese children with IR and folic acid is an appropriate supplement for obese children with increased inflammatory factors.

Potent Human α-Amylase Inhibition by the β-Defensin-like Protein Helianthamide

Selective inhibitors of human pancreatic α-amylase (HPA) are an effective means of controlling blood sugar levels in the management of diabetes. A high-throughput screen of marine natural product extracts led to the identification of a potent (K_i = 10 pM) peptidic HPA inhibitor, helianthamide, from the Caribbean sea anemone Stichodactyla helianthus. Active helianthamide was produced in Escherichia coli via secretion as a barnase fusion protein. X-ray crystallographic analysis of the complex of helianthamide with porcine pancreatic α-amylase revealed that helianthamide adopts a β-defensin fold and binds into and across the amylase active site, utilizing a contiguous YIYH inhibitory motif. Helianthamide represents the first of a novel class of glycosidase inhibitors and provides an unusual example of functional malleability of the β-defensin fold, which is rarely seen outside of its traditional role in antimicrobial peptides.

Type 2 diabetes in adolescents

At the same time they are reporting the current obesity epidemic, U.S. physicians are also seeing a dramatic increase in the prevalence of type 2 diabetes in adolescent patients. In this article, Drs Laurencin, Goldschmidt, and Fisher summarize the prevalence and risk factors, clinical presentation, diagnosis, and treatment of type 2 diabetes in adolescents. They also offer interventional strategies for both lifestyle change and pharmacologic management.

Overweight and obesity in children and adolescents

Obesity among children, adolescents and adults has emerged as one of the most serious public health concerns in the 21st century. The worldwide prevalence of childhood obesity has increased remarkably over the past 3 decades. The growing prevalence of childhood obesity has also led to appearance of obesity-related comorbid disease entities at an early age. Childhood obesity can adversely affect nearly every organ system and often causes serious consequences, including hypertension, dyslipidemia, insulin resistance, dysglycemia, fatty liver disease and psychosocial complications. It is also a major contributor to increasing healthcare expenditures. For all these reasons, it is important to prevent childhood obesity as well as to identify overweight and obese children at an early stage so they can begin treatment and attain and maintain a healthy weight. At present, pharmacotherapy options for treatment of pediatric obesity are very limited. Therefore, establishing a comprehensive management program that emphasizes appropriate nutrition, exercise and behavioral modification is crucial. The physician's role should expand beyond the clinical setting to the community to serve as a role model and to advocate for prevention and early treatment of obesity.

Association of attention-deficit/hyperactivity disorder with diabetes: a population-based study

BACKGROUND

Cognitive impairment has been documented in adult diabetes but is unclear in pediatric diabetes. No study had been conducted to explore the relationship between attention-deficit/hyperactivity disorder (ADHD) and diabetes. Using a population-based data set, we aimed to examine the association between ADHD and a prior diagnosis of diabetes mellitus (DM) in Taiwan.

METHODS

A total of 4,302 patients with ADHD were selected as cases and 21,510 randomly selected subjects as controls. We used conditional logistic regression to calculate the odds ratio (OR) for having previously received a diagnosis of DM between subjects with and without ADHD.

RESULTS

In this study, 116 of the 25,812 sampled subjects (0.5%) had received a diagnosis of DM prior to their index date. Subjects with ADHD had a higher proportion of prior DM diagnoses than controls (0.9% vs. 0.4%, P < 0.001). After adjusting for age, sex, index year, geographic location, and obesity, ADHD was significantly associated with a prior diagnosis of type 2 DM (OR = 2.75, 95% confidence interval (CI) = 1.82-4.16). However, no significant association was observed between ADHD and type 1 DM.

CONCLUSION

The findings suggest that ADHD was associated with a previous diagnosis of type 2 DM.

Maladaptive eating patterns in children

Given the increasing frequency of obesity and related maladaptive eating patterns in pediatric populations, health care professionals in a variety of settings must find ways to treat persons who are obese and have maladaptive eating patterns. The authors summarized literature related to binge eating disorder, boredom eating, emotional eating, and night eating syndrome and developed educational handouts designed for children/adolescents and their families who present with these eating problems. These educational handouts may be used by primary care physicians, psychologists, psychiatrists, nurses, and other specialists in medical settings. They are free for use in educational purposes, with permission from the authors, but are not intended to replace appropriate health care and follow-up.

Obese Adolescents with Type 2 Diabetes Mellitus Have Hippocampal and Frontal Lobe Volume Reductions

The rates of type 2 diabetes (T2DM) continue to parallel the rising rates of obesity in the United States, increasingly affecting adolescents as well as adults. Hippocampal and frontal lobe reductions have been found in older adults with type 2 diabetes, and we sought to ascertain if these brain alterations were also present in obese adolescents with T2DM. In a cross-sectional study we compared MRI-based regional brain volumes of 18 obese adolescents with T2DM and 18 obese controls without evidence of marked insulin resistance. Groups were matched on age, sex, school grade, ethnicity, socioeconomic status, body mass index, and waist circumference. Relative to obese controls, adolescents with T2DM had significantly reduced hippocampal and prefrontal volumes, and higher rates of global cerebral atrophy. Hemoglobin A1c, an index of long-term glycemic control, was inversely associated with prefrontal volume and positively associated with global cerebral atrophy (both p < 0.05). Brain integrity is negatively impacted by T2DM already during adolescence, long before the onset of overt macrovascular disease. Paralleling the findings of greater vascular and renal complications among obese adolescents with severe insulin resistance and T2DM relative to their age-matched peers with type 1 diabetes, we find clear evidence of possible brain complications. Our findings call for aggressive and early intervention to limit the negative impact of obesity-associated insulin resistance leading to T2DM on the developing brains of adolescents.

B-vitamin consumption and the prevalence of diabetes and obesity among the US adults: population based ecological study

BACKGROUND

The global increased prevalence of obesity and diabetes occurred after the worldwide spread of B-vitamins fortification, in which whether long-term exposure to high level of B vitamins plays a role is unknown. Our aim was to examine the relationships between B-vitamins consumption and the obesity and diabetes prevalence.

METHODS

This population based ecological study was conducted to examine possible associations between the consumption of the B vitamins and macronutrients and the obesity and diabetes prevalence in the US population using the per capita consumption data from the US Economic Research Service and the prevalence data from the US Centers for Disease Control and Prevention.

RESULTS

The prevalences of diabetes and adult obesity were highly correlated with per capita consumption of niacin, thiamin and riboflavin with a 26-and 10-year lag, respectively (R2 = 0.952, 0.917 and 0.83 for diabetes, respectively, and R2 = 0.964, 0.975 and 0.935 for obesity, respectively). The diabetes prevalence increased with the obesity prevalence with a 16-year lag (R2 = 0.975). The relationships between the diabetes or obesity prevalence and per capita niacin consumption were similar both in different age groups and in male and female populations. The prevalence of adult obesity and diabetes was highly correlated with the grain contribution to niacin (R2 = 0.925 and 0.901, respectively), with a 10-and 26-year lag, respectively. The prevalence of obesity in US adults during 1971-2004 increased in parallel with the increase in carbohydrate consumption with a 10-year lag. The per capita energy and protein consumptions positively correlated with the obesity prevalence with a one-year lag. Moreover, there was an 11-year lag relationship between per capita energy and protein consumption and the consumption of niacin, thiamin and riboflavin (R2 = 0.932, 0.923 and 0.849 for energy, respectively, and R2 = 0.922, 0.878 and 0.787 for protein, respectively).

CONCLUSIONS

Long-term exposure to high level of the B vitamins may be involved in the increased prevalence of obesity and diabetes in the US in the past 50 years. The possible roles of B-vitamins fortification and excess niacin consumption in the increased prevalence of obesity and diabetes were discussed.

Childhood obesity: current literature, policy and implications for practice

THE PROBLEM

In most of the industrialized world, a childhood obesity epidemic is evident, with the numbers rising each year.

PURPOSE

To discuss the current literature in relation to childhood obesity and to provide health practitioners, especially nurses, with the fundamental knowledge that is imperative in the recognition of children who are at risk and thereby tailor appropriate interventions.

METHOD

Databases that were accessed for current literature included CINAHL, Science Direct and ProQuest. Keywords used in the search included obesity, childhood, health, relevant national statistics, policy and health risks. The literature was confined to the past 10 years with emphasis on the past 5 years. The 50 most pertinent papers from a variety of countries were chosen, and 35 papers that represented key areas of relevance were selected as the basis of this article. This selection of papers dictated the key areas of discussion such as the acknowledged factors in childhood obesity.

FINDINGS

Although childhood obesity may be related to specific cultural and national circumstances, universal themes emerged from the literature review. These include social factors, exercise, advertising, public policy and the importance of partnerships in policy.

CONCLUSION

Any country that has a high rate or increasing rate of childhood obesity must acknowledge core factors that contribute to this serious health problem. Furthermore, public policy and community partnerships that include all health professionals have a responsibility in the prevention of childhood obesity. This can be implemented through education, research and advocacy of all nurses involved with children and families.

Insulin resistance and impaired glucose tolerance in overweight and obese Costa Rican schoolchildren

BACKGROUND

Worldwide obesity has become an unprecedented public health challenge. In addition, a notable increase in the risk of insulin resistance and type 2 diabetes mellitus has emerged. In Costa Rica, there are no epidemiological data to establish the prevalence of type 2 diabetes in the pediatric population. However, information from the Endocrinology Department of the Children's National Hospital indicates an increased number of cases in the last 2 to 3 years.

OBJECTIVE

To determine the prevalence of insulin resistance and impaired glucose tolerance in overweight and obese schoolchildren.

METHODS

This cross-sectional study was conducted among 214 healthy 8- to 10-year-old children from urban schools of San José, Costa Rica. Anthropometric measurements and blood determinations of glucose, insulin, proinsulin, glycosylated hemoglobin, C-peptide, and leptin were performed. Indexes were calculated to assess insulin resistance. Information on social and lifestyle variables was obtained from questionnaires, and acanthosis nigricans was certified by a physician. Statistical analysis was performed with SPSS software for Windows, version 10.0.

RESULTS

The prevalence of type 2 diabetes mellitus was very low (0.5%) in the studied population. However, hyperinsulinemia and impaired glucose tolerance were present in 20.6% and 6.5% of the subjects, respectively. On the basis of the Fasting Glucose-to-Insulin Resistance Ratio (FGIR), 46.7% of the children showed insulin resistance. Girls and obese children (body mass index > or = 95th percentile) were more likely to have higher serum insulin levels and insulin resistance than boys and overweight children (BMI > or = 85th percentile). Compared with the lowest quintile, children in the highest quintile of body-fat tissue had higher insulin resistance but had similar serum concentrations of glucose, C-peptide, and proinsulin. Positive family histories of type 2 diabetes mellitus and sedentarism (73.7% and 40.7%, respectively) were highly prevalent among overweight and obese children.

CONCLUSIONS

The prevalence of impaired glucose tolerance and insulin resistance in obese children indicates a worrisome trend in the incidence of type 2 diabetes in Costa Rica. Strategies for weight reduction, obesity prevention, and promotion of healthy lifestyles are necessary to prevent the onset of type 2 diabetes during childhood and adolescence.

The association between mothers' psychopathology, childrens' competences and psychological well-being in obese children

BACKGROUND

The prevalence of childhood obesity is rapidly increasing, and many obese children suffer from emotional and behavior problems and mental disorders. Associations with social stigmatization of obesity, maternal psychopathology, socioeconomic status (SES) and resilience factors are discussed.

OBJECTIVE

We hypothesize maternal psychopathology to have an impact on the psychological well-being of an obese child. We further hypothesize that competence factors within the child are important key factors that influence the way a child deals with the psychological burden of obesity.

METHOD

A referred clinical sample of 59 obese children with their mothers was assessed using a structured clinical interview for DSM-IV diagnosis and questionnaires for child and maternal psychopathology, SES, body mass index (BMI), and percent overweight. Correlations, hierarchical linear and logistic regression models were used to analyze associations between mothers and child and the impact of potential predictors.

RESULTS

Mental disorders were found in 37.3% of the obese children in our sample. Maternal anxiety predicted the mother reported child's internalizing problems as well as the child's depression and anxiety self report scores. The mental disorder status of the mother predicted the child's internalizing problems, and maternal binge eating disorder (BED) had an impact on the mental disorder of the child. If the child's total competences were included in the hierarchical regression model they predicted the child's outcome in all three subscales of the Child Behavior Checklist (CBCL), thereby reducing the effect of maternal anxiety to influencing the child's depression score only. Neither SES nor the child's percent overweight accounted for the child's wellbeing.

CONCLUSIONS

Although maternal psychopathology and diagnosis of mental disorder had some impact on the psychological well-being of the child, the child's competences showed a significant negative association with the problem scales. More research on parental and children's skills and competences will highlight the complex interaction of childhood obesity, comorbidity of mental disorders, and resilience factors and will lead to additional approaches for intervention.

Evaluation of risk profiles by subcutaneous adipose tissue topography in obese juveniles

OBJECTIVE

To compare subcutaneous adipose tissue topography (SAT-top) in obese juveniles with age-matched normal-weight controls.

RESEARCH METHODS AND PROCEDURES

The optical device LIPOMETER (European Patent EP 0516251) enables the non-invasive, rapid, safe, and precise measurement of the thickness of subcutaneous adipose tissue. Fifteen defined body sites (1 = neck to 15 = calf) characterize the individual SAT-top like an individual fingerprint. SAT-top of 1351 juveniles (obese: 42 boys, 59 girls, normal weight: 680 boys, 570 girls) from 7 to 19 years of age were measured. For visual comparison, the 15-dimensional SAT-top information was condensed by factor analysis into a two-dimensional factor plot.

RESULTS

Both female and male obese juveniles had markedly increased adipose tissue layers at 7 = upper abdomen, 8 = lower abdomen, 5 = front chest, and 6 = lateral chest. The pubertal changes of body shape and fat distribution of the normal-weight boys and girls (boys show thinner adipose tissue layers on their legs, whereas girls had thicker adipose tissue layers at the extremities) were not seen in the obese group. Independently of age and sex, all of the obese juveniles showed a similar, more android body fat distribution with increased trunk fat.

DISCUSSION

SAT-top of the obese juveniles is similar to that of patients with type 2 diabetes, polycystic ovary syndrome, and coronary heart disease. Patients with these metabolic disorders and obese juveniles are located in the factor plot in the same area. This body shape may indicate a risk profile for developing polycystic ovary syndrome (women), type 2 diabetes, and early atherosclerosis (both sexes).

Limitations of diabetes pharmacotherapy: results from the Vermont Diabetes Information System study

BACKGROUND

There are a wide variety of medications available for the treatment of hyperglycemia in diabetes, including some categories developed in recent years. The goals of this study were to describe the glycemic medication profiles in a cohort of adult patients enrolled in primary care, to compare the regimens with measures of glycemic control, and to describe potential contraindicated regimens.

METHODS

One thousand and six subjects with diabetes cared for in community practices in the Northeast were interviewed at home at the time of enrollment in a trial of a diabetes decision support system. Laboratory data were obtained directly from the clinical laboratory. Current medications were obtained by direct observation of medication containers by a research assistant.

RESULTS

The median age of subjects was 63 years; 54% were female. The mean A1C was 7.1%, with 60% of subjects in excellent glycemic control (A1C < 7%). Ninety percent of patients were taking 2 or fewer medications for glycemic control, with a range of 0 to 4 medications. Insulin was used by 18%. As the number of diabetes medications increased from 0 to 4, the A1C increased from 6.5% to 9.2% (p < 0.001). The association between glycemic control and number of glycemic medications was confirmed using logistic regression, controlling for potential confounders. Almost 20% of subjects on metformin or thiazolidenediones had potential contraindications to these medications.

CONCLUSION

Patients with diabetes cared for in primary care are on a wide variety of medication combinations for glycemic control, though most are on two or fewer medications. A greater number of diabetes medications is associated with poorer glycemic control, reflecting the limitations of current pharmacotherapy. One quarter of patients are on glycemic medications with potential contraindications.

Prevalence of risk for type 2 diabetes in school children

According to the Centers for Disease Control and Prevention, 1 in 3 children born in 2000 in the United States will become diabetic. The odds are higher for African American and Hispanic children as nearly 50% of them will develop diabetes. Random screening is not effective in identifying children at risk for type 2 diabetes mellitus (T2DM); therefore, there is a need to apply screening strategies that guide the development of appropriate primary prevention efforts. To assess the prevalence of risk factors for T2DM, 1066 fifth-grade children were screened using American Diabetes Association guidelines. Overall, 22.6% were found at risk; African American and Hispanic children were almost 8 times more likely to be at risk when compared to Caucasians (odds ratio = 7.41 and 7.87). Children who reported watching TV/playing video games 2 or more hours/day were 73% more likely to be at risk. Children identified to be at risk were referred to their primary care provider and were invited to participate in a counseling session. The environmental risk factors for T2DM identified in this study are modifiable and should be targeted in preventive interventions at the school and community level to reduce overweight and consequently prevent T2DM in children, especially among minority children.

Type 2 diabetes mellitus in African-American adolescents: impaired beta-cell function in the face of severe insulin resistance

We have previously demonstrated abnormalities in insulin secretion in adolescents with type 2 diabetes mellitus (DM2) in response to the mixed meal test and to glucagon. In order to further assess beta-cell function in DM2, we measured insulin and C-peptide responses to oral glucose in adolescents with DM2 in comparison to non-diabetic obese and lean adolescents. We studied 20 patients with DM2, 25 obese adolescents with matching body mass index (BMI) (33.8 +/- 1.4 vs 34.3 +/- 1.0 kg/m2), and 12 non-obese control adolescents (BMI 22.6 +/- 0.6 kg/m2). Mean age, sex and sexual maturation did not differ between the three groups. All adolescents with DM2 had negative islet cell antibodies (ICA); five patients were on diet and 15 on insulin treatment. Fasting lipid profiles were determined in all participants. Plasma glucose and serum C-peptide and insulin levels were measured at 0, 30, 60, 90, and 120 min after an oral glucose load. The C-peptide increment (deltaCP) was calculated as peak minus fasting C-peptide. Area under the curve (AUC) was estimated using the trapezoid method. Insulin resistance was estimated using the HOMA model (HOMA-IR). The first phase of insulin secretion (PH1) was computed using a previously published formula. Serum triglyceride levels were significantly higher in the patients with DM2 compared to the non-obese controls (1.4 +/- 0.1 vs 0.9 +/- 0.1 mmol/l; p = 0.02). Plasma glucose AUC was greater in the patients with DM2 compared to the obese and non-obese control groups (1,660 +/- 130 vs 717 +/- 17 vs 647 +/- 14 mmol/l x min; p < 0.0001). ACP was lower in adolescents with DM2 than in obese and non-obese adolescents (761 +/- 132 vs 1,721 +/- 165 vs 1,225 +/- 165 pmol/l; p < 0.001). Insulin AUC was lower in the patients with DM2 compared to obese controls (888 +/- 206 vs 1,606 +/- 166 pmol/l x h; p = 0.009), but comparable to that of the non-obese controls (888 +/- 206 vs 852 +/- 222 pmol/l x h; p = 0.9). Insulin AUC was also higher in the obese than in the non-obese group (p = 0.05). PH1 was significantly higher in the obese group compared to the patients with DM2 as well as to the non-obese controls (2,614 +/- 2,47.9 vs 929.6 +/- 403.5 vs 1,946 +/- 300.6 pmol/l, respectively; p = 0.001). PH1 was also higher in the non-obese controls than in the patients with DM2 (p = 0.05). HOMA-IR was three-fold higher in the patients with DM2 than in the BMI-matched obese group, and five-fold higher than in the lean controls (14.3 +/- 1.2 vs 5.4 +/- 0.8 vs 2.9 +/- 0.4; p = 0.0002). Adolescents with DM2 have dyslipidemia, a significant cardiovascular risk factor. Decreased beta-cell function is characteristic of adolescents with DM2 in the presence of severe insulin resistance.

Current knowledge in the neurophysiologic modulation of obesity

Obesity is today one of the commonest of life-threatening diseases in developed countries and generally results from an imbalance between energy intake and energy expenditure. Although there is increasing evidence for a genetic basis of obesity in some clinical syndromes, this seems to be the cause only in a limited number of patients and obesity is far from being considered as a gene-related disease. Eating is a complex and multifactorial process involving autonomous pathways that transfer sensory and motor information between the entire length of the digestive tract and the central nervous system. Modulation of the amount of energy that we take in as food involves several mechanisms and networks that connect the brain with the gut, this process being key to the regulation of body weight over time, as well as to the modification of long-term eating behaviors. Furthermore, this axis is closely coupled to other systems that are involved in energy homeostasis, namely, food preference, energy expenditure, and lifestyle. The identification of several neuropeptides that modulate eating behavior in various ways, along with studies performed in animal models, have focused attention on the role of these molecules and their clinical implications in the development of obesity in humans.

Obesity and fat quantification in lean tissues using three-point Dixon MR imaging

BACKGROUND

It has been suggested that increased hepatic and intramuscular fat is associated with insulin resistance, and that increased pancreatic fat is related to impaired insulin secretion.

OBJECTIVE

We postulated that in obese nondiabetic teenagers insulin levels would be directly related to increases in intramuscular and hepatic fat and inversely related to increases in pancreatic fat.

MATERIALS AND METHODS

MRI was used to assess the percentage of fat in the liver, muscle and pancreas in 15 healthy Mexican-American girls, 14-17 years old, with body mass indexes (BMIs) ranging from 17.7 kg/m(2) to 46 kg/m(2).

RESULTS

Strong correlations were observed between BMI and fat content in the liver, muscle, and pancreas (r(2)s between 0.50 and 0.89; P<0.003). Serum insulin levels were closely associated with fat measures in the muscle and liver (r(2s)=0.63 and 0.29, and P=0.001 and P=0.023, respectively). In contrast to our hypothesis, fat content in the pancreas was also directly related to insulin secretion (r(2)=0.74; P=0.001).

SUMMARY

We conclude that in nondiabetic teenagers, obesity is associated with an increased accumulation of fat in the pancreas without impairment of insulin secretion.

COMPETING DIETARY CLAIMS FOR WEIGHT LOSS: Finding the Forest Through Truculent Trees

In response to an accelerating obesity pandemic, competing weight-loss diets have propagated; those touting carbohydrate restriction are currently most in vogue. Evidence that sustainable weight loss is enhanced by means other than caloric restriction, however, is lacking. Whereas short-term weight loss is consistently achieved by any dietary approach to the restriction of choice and thereby calories, lasting weight control is not. Competing dietary claims imply that fundamental knowledge of dietary pattern and human health is lacking; an extensive literature belies this notion. The same dietary and lifestyle pattern conducive to health promotion is consistently associated with weight control. A bird's eye view of the literature on diet and weight reveals a forest otherwise difficult to discern through the trees. Competing diet claims are diverting attention and resources from what is actually and urgently needed: a dedicated and concerted effort to make the basic dietary pattern known to support both health and weight control more accessible to all.

Diabetes mellitus tipo 2 en la edad pediátrica

In the past two decades, type 2 diabetes mellitus has increased in children and adolescents, especially within certain ethnic groups. This increase has been parallel to the rising prevalence of obesity. Because of the overlap between some clinical characteristics, the differential diagnosis between type 1 and 2 diabetes is difficult. Of 300 diabetic patients in our diabetes section, only three (1 %) had type 2 diabetes. Two patients were obese adolescents with a positive family history of type 2 diabetes mellitus; the third patient was a prepubertal, overweight girl with no family history of this disorder. The diagnosis was incidental in two patients and one patient presented with ketoacidosis. The differences between the three patients reveal the great clinical variability of this disorder and suggest that various underlying factors are involved in the pathophysiology of type 2 diabetes.

A common polymorphism in the upstream promoter region of the hepatocyte nuclear factor-4 alpha gene on chromosome 20q is associated with type 2 diabetes and appears to contribute to the evidence for linkage in an ashkenazi jewish population

Variants in hepatocyte nuclear factor-4 alpha (HNF4 alpha), a transcription factor that influences the expression of glucose metabolic genes, have been correlated with maturity-onset diabetes of the young, a monogenic form of diabetes. Previously, in a genome scan of Ashkenazi Jewish type 2 diabetic families, we observed linkage to the chromosome 20q region encompassing HNF4 alpha. Here, haplotype-tag single nucleotide polymorphisms (htSNPs) were identified across a 78-kb region around HNF4 alpha and evaluated in an association analysis of Ashkenazi Jewish type 2 diabetic (n = 275) and control (n = 342) subjects. We found that two of nine htSNPs were associated with type 2 diabetes: a 3' intronic SNP, rs3818247 (29.2% case subjects vs. 21.7% control subjects; P = 0.0028, odds ratio [OR] 1.49) and a 5' htSNP located approximately 3.9 kb upstream of P2, rs1884614 (26.9% case subjects vs. 20.3% control subjects; P = 0.0078, OR 1.45). Testing of additional SNPs 5' of rs1884614 revealed a >10-kb haplotype block that was associated with type 2 diabetes. Conditioning on the probands' rs1884614 genotype suggested that the chromosomal region identified by the htSNP accounted for the linkage signal on chromosome 20q in families in which the proband carried at least one risk allele. Notably, the associations and the partitioned linkage profiles near P2 were independently observed in a Finnish sample, suggesting the presence of potential regulatory element(s) that may contribute to the risk for type 2 diabetes.