Modern, new pharmacotherapy for obesity. A gastrointestinal approach

Predictive Equations Overestimate Resting Metabolic Rate in Young Chilean Women with Excess Body Fat

Underestimating/overestimating resting metabolic rate (RMR) affects energy prescription. The objective was to compare RMR by indirect calorimetry (RMR IC) and RMR estimated by predictive equations in women with excess body fat. This was an analytical cross-sectional study with 41 women aged 18-28 with overnutrition according to body composition. The RMR IC was measured and RMR estimated using the FAO/WHO/UNU (1985), FAO/WHO/UNU (2004), Harris-Benedict, and Mifflin-St Jeor equations. The percentage of adequacy (90-110%), overestimation (>110%), and underestimation (<90%) were evaluated for RMR IC. Data were described by percentiles because of non-normal distribution according to the Shapiro-Wilk test. The Kruskal-Wallis test and Bland-Altman analysis were applied at a significance level of α < 0.05. The RMR IC was 1192 and 1183 calories/day (p = 0.429) in women with obesity and overweight, respectively. The FAO/WHO/UNU (1985), FAO/WHO/UNU (2004), Harris-Benedict, and Mifflin-St Jeor equations overestimated the RMR IC by 283.2, 311.2, 292.7, and 203.0 calories/day and by 296.7, 413.8, 280.0, and 176.6 calories/day for women with overweight and obesity (p < 0.001), respectively. The Harris-Benedict adjusted weight (0.5) equation underestimated RMR IC by 254.7 calories/day. The predictive equations overestimated RMR IC in women with excess body fat. The Mifflin-St Jeor equation showed less overestimation and better adequacy, but was not exempt from inaccuracy.

Low serum amylase and obesity, diabetes and metabolic syndrome: A novel interpretation

For the last decade, low serum amylase (hypoamylasemia) has been reported in certain common cardiometabolic conditions such as obesity, diabetes (regardless of type), and metabolic syndrome, all of which appear to have a common etiology of insufficient insulin action due to insulin resistance and/or diminished insulin secretion. Some clinical studies have shown that salivary amylase may be preferentially decreased in obese individuals, whereas others have revealed that pancreatic amylase may be preferentially decreased in diabetic subjects with insulin dependence. Despite this accumulated evidence, the clinical relevance of serum, salivary, and pancreatic amylase and the underlying mechanisms have not been fully elucidated. In recent years, copy number variations (CNVs) in the salivary amylase gene (AMY1), which range more broadly than the pancreatic amylase gene (AMY2A and AMY2B), have been shown to be well correlated with salivary and serum amylase levels. In addition, low CNV of AMY1, indicating low salivary amylase, was associated with insulin resistance, obesity, low taste perception/satiety, and postprandial hyperglycemia through impaired insulin secretion at early cephalic phase. In most populations, insulin-dependent diabetes is less prevalent (minor contribution) compared with insulin-independent diabetes, and obesity is highly prevalent compared with low body weight. Therefore, obesity as a condition that elicits cardiometabolic diseases relating to insulin resistance (major contribution) may be a common determinant for low serum amylase in a general population. In this review, the novel interpretation of low serum, salivary, and pancreas amylase is discussed in terms of major contributions of obesity, diabetes, and metabolic syndrome.

The role of lipid and carbohydrate digestive enzyme inhibitors in the management of obesity: a review of current and emerging therapeutic agents

Obesity is a global epidemic associated with significant morbidity and mortality in adults and ill health in children. A proven successful approach in weight management has been the disruption of nutrient digestion, with orlistat having been used to treat obesity for the last 10 years. Although orlistat-induced weight loss remains modest, it produces meaningful reductions in risk factors for obesity-related conditions such as diabetes and cardiovascular disease. Moreover, this lipase inhibitor is free of the serious side effects that have dogged appetite-suppressing drugs. This success had driven investigation into new generation nutraceuticals, supplements and pharmaceutical agents that inhibit the breakdown of complex carbohydrates and fats within the gut. This review focuses on agents purported to inhibit intestinal enzymes responsible for macronutrient digestion. Except for some synthetic products, the majority of agents reviewed are either botanical extracts or bacterial products. Currently, carbohydrate digestion inhibitors are under development to improve glycemic control and these may also induce some weight loss. However, colonic fermentation induced side effects, such as excess gas production, remain an issue for these compounds. The α-glucosidase inhibitor acarbose, and the α-amylase inhibitor phaseolamine, have been used in humans with some promising results relating to weight loss. Nonetheless, few of these agents have made it into clinical studies and without any clinical proof of concept or proven efficacy it is unlikely any will enter the market soon.

The aqueous extract of Hibiscus sabdariffa calices modulates the production of monocyte chemoattractant protein-1 in humans

Diet supplementation and/or modulation is an important strategy to significantly improve human health. The search of plants as additional sources of bioactive phenolic compounds is relevant in this context. The aqueous extract of Hibiscus sabdariffa is rich in anthocyanins and other phenolic compounds including hydroxycitric and chlorogenic acids. Using this extract we have shown an effective protection of cultured peripheral blood mononuclear cells from the cellular death induced by H(2)O(2) and a significant role in the production of inflammatory cytokines. In vitro, the extract promotes the production of IL-6 and IL-8 and decreases the concentration of MCP-1 in supernatants in a dose-dependent manner. In humans, the ingestion of an acute dose of the extract (10g) was well tolerated and decreased plasma MCP-1 concentrations significantly without further effects on other cytokines. This effect was not due to a concomitant increase in the antioxidant capacity of plasma. Instead, its mechanisms probably involve a direct inhibition of inflammatory and/or metabolic pathways responsible for MCP-1 production, and may be relevant in inflammatory and chronic conditions in which the role of MCP-1 is well established. If beneficial effects are confirmed in patients, Hibiscus sabdariffa could be considered a valuable traditional herbal medicine for the treatment of chronic inflammatory diseases with the advantage of being devoid of caloric value or potential alcohol toxicity.

Alanine substitutions of noncysteine residues in the cysteine-stabilized alphabeta motif

The protein scaffold is a peptide framework with a high tolerance of residue modifications. The cysteine-stabilized alphabeta motif (CS alphabeta) consists of an alpha-helix and an antiparallel triple-stranded beta-sheet connected by two disulfide bridges. Proteins containing this motif share low sequence identity but high structural similarity and has been suggested as a good scaffold for protein engineering. The Vigna radiate defensin 1 (VrD1), a plant defensin, serves here as a model protein to probe the amino acid tolerance of CS alphabeta motif. A systematic alanine substitution is performed on the VrD1. The key residues governing the inhibitory function and structure stability are monitored. Thirty-two of 46 residue positions of VrD1 are altered by site-directed mutagenesis techniques. The circular dichroism spectrum, intrinsic fluorescence spectrum, and chemical denaturation are used to analyze the conformation and structural stability of proteins. The secondary structures were highly tolerant to the amino acid substitutions; however, the protein stabilities were varied for each mutant. Many mutants, although they maintained their conformations, altered their inhibitory function significantly. In this study, we reported the first alanine scan on the plant defensin containing the CS alphabeta motif. The information is valuable to the scaffold with the CS alphabeta motif and protein engineering.

Feeding induced changes in the hypothalamic transcriptome

BACKGROUND

Obesity is a complex multifactorial disorder which needs a comprehensive approach for prevention and treatment. We investigated the modifications in the hypothalamic gene expression induced by high-fat (HF) and low-fat (LF) meal ingestion in mice, in order to identify the signals rapidly mediating the hypothalamic control on energy intake.

METHODS

After fasting, 1 group of mice was sacrificed and the others were fed ad libitum with HF or LF diet, and sacrificed 3 h after the beginning of the meal. The hypothalamus was sampled and the serial analysis of gene expression method was performed.

RESULTS

Approximately 254,588 tags, which correspond to 65,548 tag species were isolated from the 3 groups. The data showed twelve transcripts regulated by food intake. Among these, 2 transcripts have mitochondrial functions (MtCo1, Ppid), 3 are involved in protein transport and regulation (Ube2q2, Mup1, Sec13), 1 in cellular pH control (Slc4a3) and another 1 has a role in the epigenetic control of gene expression (Setd3). In addition, 5 potentially novel transcripts were differentially modulated.

CONCLUSION

We identified genes that may regulate hypothalamic circuits governing the early response to food intake. 3 genes were specifically modulated by high-fat intake.

Lipases at interfaces: a review

Lipases are acyl hydrolases that play a key role in fat digestion by cleaving long-chain triglycerides into polar lipids. Due to an opposite polarity between the enzyme (hydrophilic) and their substrates (lipophilic), lipase reaction occurs at the interface between the aqueous and the oil phases. Hence, interfaces are the key spots for lipase biocatalysis and an appropriate site for modulating lipolysis. Surprisingly enough, knowledge about the effects of the interfacial composition on lipase catalysis is still limited and only described by the term "interfacial quality". Recent systematic studies based on a biophysical approach allowed for the first time to show the effects of the interfacial microenvironment on lipase catalysis. These studies demonstrate that lipase activity as a function of interfacial composition is more attributed to substrate inaccessibility rather than to enzyme denaturation or inactivation, as it is often hypothesized. A detailed analysis of the interfacial properties of all compounds involved in triglyceride digestion revealed that lipolysis is a self-regulated reaction. This feedback mechanism can be explored as a new avenue to control lipase catalysis. To substantiate this hypothesis, oil hydrolysis in a model gastro-intestinal system was performed, which can be seen as an interfacial engineering approach to enzyme reactivity control. The presented characterization of the interfacial composition and its consequences provide a new approach for the understanding of lipase reactions at interfaces with direct impact on biotechnological and health care applications.

Influence of Surfactants on Lipase Fat Digestion in a Model Gastro-intestinal System

In the present study, we use a model gastro-intestinal system to study the influence of different food-grade surface-active molecules (Sn-2 monopalmitin, beta-lactoglobulin, or lysophosphatodylcholine) on lipase activity. The interfacial activity of lipase and surfactants are assessed with the pendant drop technique, a commonly used tensiometry instrument. A mathematical model is adopted which enables quantitative determination of the composition of the water-oil interface as a function of bulk surfactant concentration in the water-oil mixtures. Our results show a decrease in gastric lipolysis when interfacially active molecules are incorporated into a food matrix. However, only the Sn-2 monopalmitin caused a systematic decrease in triglyceride hydrolysis throughout the gastro-intestinal tract. This effect is most likely due to exclusion of both lipase and triglyceride from the water-oil interface together with a probable saturation of the solubilization capacity of bile with monoglycerides. Addition of beta-lactoglobulin or lysophopholipids increased the hydrolysis of fat after the gastric phase. These results can be attributed to an increasing interfacial area with lipase and substrate present at the interface. Otherwise, beta-lactoglobulin, or lysophopholipids reduced fat hydrolysis in the stomach. From the mathematical modeling of the interface composition, we can conclude that Sn-2 monopalmitin can desorb lipase from the interface, which, together with exclusion of substrate from the interface, explains the gradually decreased triglyceride hydrolysis that occurs during the digestion. Our results provide a biophysics approach on lipolysis that can bring new insights into the problem of fat uptake.

Treatment of morbid obesity by intraparietogastric administration of botulinum toxin: a randomized, double-blind, controlled study

OBJECTIVE

The stomach is the main target organ for bariatric surgery, but no medical treatment has been developed to increase satiety and decrease food intake via gastric pathways. The aim of our study was to investigate whether or not the intraparietogastric administration of botulinum toxin A (BTX), able to modify the motility patterns of the stomach, could be useful for treatment of obesity.

DESIGN

Double blind controlled study.

SUBJECTS

Twenty-four morbidly obese patients (mean weight (s.e.m.) 116.1+/-4.89 kg, mean body mass index (BMI) 43.6+/-1.09 kg/m(2)) were blindly randomized to receive 200 IU BTX or placebo into the antrum and fundus of the stomach by intraparietal endoscopic administration.

MEASUREMENTS

We evaluated weight loss, BMI changes, satiety score, the maximal gastric capacity for liquids and the gastric emptying time (octanoic acid breath test).

RESULTS

The two groups were homogeneous for anthropometric characteristics. Eight weeks after treatment, BTX patients had significantly higher weight loss (11+/-1.09 vs 5.7+/-1.1 kg, P<0.001) and BMI reduction (4+/-0.36 vs 2+/-0.58 kg/m(2), P<0.001) and a higher satiety score on a visual analogic scale (7.63+/-0.38 vs 4.72+/-0.44, P<0.001) than controls. Furthermore, BTX patients showed a significantly greater reduction in maximal gastric capacity for liquids (266.6+/-48 vs 139+/-31, P<0.001) and a greater prolongation in gastric emptying time (+18.93+/-8 vs -2.2+/-6.9 min, P<0.05). No significant side effects or neurophysiologic changes were found.

CONCLUSIONS

Topical intragastric BTX was effective in reducing food intake and body weight in morbidly obese patients.