Biomaterials that regulate fat digestion for the treatment of obesity

Targeting the gut microbiome to control drug pharmacomicrobiomics: the next frontier in oral drug delivery

INTRODUCTION

The trillions of microorganisms that comprise the gut microbiome form dynamic bidirectional interactions with orally administered drugs and host health. These relationships can alter all aspects of drug pharmacokinetics and pharmacodynamics (PK/PD); thus, there is a desire to control these interactions to maximize therapeutic efficacy. Attempts to modulate drug-gut microbiome interactions have spurred advancements within the field of 'pharmacomicrobiomics' and are poised to become the next frontier of oral drug delivery.

AREAS COVERED

This review details the bidirectional interactions that exist between oral drugs and the gut microbiome, with clinically relevant case examples outlining a clear motive for controlling pharmacomicrobiomic interactions. Specific focus is attributed to novel and advanced strategies that have demonstrated success in mediating drug-gut microbiome interactions.

EXPERT OPINION

Co-administration of gut-active supplements (e.g. pro- and pre-biotics), innovative drug delivery vehicles, and strategic polypharmacy serve as the most promising and clinically viable approaches for controlling pharmacomicrobiomic interactions. Targeting the gut microbiome through these strategies presents new opportunities for improving therapeutic efficacy by precisely mediating PK/PD, while mitigating metabolic disturbances caused by drug-induced gut dysbiosis. However, successfully translating preclinical potential into clinical outcomes relies on overcoming key challenges related to interindividual variability in microbiome composition and study design parameters.

Effects of Free Linoleic Acid and Oleic Acid in Sesame Meal Extract as Pancreatic Lipase Inhibitors on Postprandial Triglyceridemia: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Volunteers

A great number of chemically diverse pancreatic lipase (PL) inhibitors have been identified to tackle obesity; however, very few of them have entered clinical studies. The ethanolic extract of sesame meal is a potent PL inhibitor, and its activity hinges exclusively on two free fatty acids: linoleic acid and oleic acid, which were proven to reduce postprandial triglyceride excursion in rats. Herein, to investigate the clinical efficacy of the sesame meal extract, in a crossover trial, 30 healthy volunteers were randomized to receive the sesame meal extract containing experimental food or placebo along with a high-fat meal. Treatment with the sesame meal extract significantly lowered the incremental postprandial serum triglyceride concentration and reduced the incremental area under the curve (iAUC) by 16.8% (p-value = 0.03) compared to placebo. Significant decreases in postprandial remnant-like lipoprotein particle cholesterol and low-density lipoprotein particles were also observed, whereas high-density lipoprotein cholesterol was increased. These results suggest that treatment with the sesame meal extract significantly reduced the postprandial excursion of triglycerides and improved the lipidemic profile after high dietary fat intake in healthy individuals, indicating the substantial potential of free linoleic acid and oleic acid and natural products rich in these compounds for the management of obesity and related conditions.

Tackling Dyslipidemia in Obesity from a Nanotechnology Perspective

Obesity and dyslipidemia are the main features of metabolic syndrome, expressed mainly by adipose tissue dysfunction and connected by similar pathways and pharmacotherapy. Conventional drugs used in these two associated disorders are limited due to poor drug efficiency, non-specificity, and toxic side effects. Therefore, novel solutions for tackling obesity-associated diseases and providing insights into the development of innovative or improved therapies are necessary. Targeted nanotherapy is a revolutionary technology, offering a promising solution for combatting the disadvantages of currently available therapies for treating obesity and dyslipidemia due to its superior features, which include specific cell targeting, the protection of drugs against physiological degradation, and sustained drug release. This review presents a brief assessment of obesity and dyslipidemia, their impacts on human health, current treatment, and limitations, and the role and potential use of nanotechnology coupled with targeted drug delivery and nutraceuticals as emerging therapies. To the best of our knowledge, this paper presents, for the first time in the literature, a comparison between obesity and dyslipidemia nano-formulations based on drugs and/or natural extracts applied in experimental studies.

The Anti-Obesity Effect of Porous Silica Is Dependent on Pore Nanostructure, Particle Size, and Surface Chemistry in an In Vitro Digestion Model

The potential for porous silica to serve as an effective anti-obesity agent has received growing attention in recent years. However, neither the exact pharmacological mechanism nor the fundamental physicochemical properties of porous silica that drive its weight-lowering effect are well understood. Subsequently, in this study, an advanced in vitro digestion model capable of monitoring lipid and carbohydrate digestion was employed to elucidate the effect of porous silica supplementation on digestive enzyme activities. A suite of porous silica samples with contrasting physicochemical properties was investigated, where it was established that the inhibitory action of porous silica on digestive enzyme functionality was strongly dependent on porous nanostructure, particle size and morphology, and surface chemistry. Insights derived from this study validate the capacity of porous silica to impede the digestive processes mediated by pancreatic lipase and α-amylase within the gastrointestinal tract, while the subtle interplay between porous nanostructure and enzyme inhibition indicates that the anti-obesity effect can be optimized through strategic particle design.

Free Linoleic Acid and Oleic Acid Reduce Fat Digestion and Absorption In Vivo as Potent Pancreatic Lipase Inhibitors Derived from Sesame Meal

Pancreatic lipase catalyzes the cleavage of triacylglycerols at the oil–water interface, and is known as the dominant determiner of dietary fat digestion. Reducing dietary fat digestion and absorption by modulating the activity of pancreatic lipase has become a favorable strategy to tackle obesity. Orlistat is, at present, the only pancreatic lipase inhibitor approved for the treatment of obesity; however, an array of gastrointestinal adverse effects associated with orlistat limits its tolerability. As a safe alternative to orlistat, a number of natural product-derived compounds with varying degrees of pancreatic lipase inhibitory activity have been reported. We herein reported that bioactivity-guided fractionation of sesame meal led to the identification of free linoleic acid and oleic acid as potent inhibitors of porcine pancreatic lipase in vitro with an IC50 of 23.1 µg/mL (82.4 µM) and 11.7 µg/mL (41.4 µM), respectively. In rats, a single oral dose of the mixture of these fatty acids significantly suppressed the elevation of blood triacylglycerol level following fat intake. These results substantiate the role of free linoleic acid and oleic acid as a novel class of natural product-derived functional molecules that act as pancreatic lipase inhibitors, and their potential for healthy, routine-based weight management.

An evolving view on food viscosity regulating gastric emptying

Viscosity is a property of most foods. The consumption of the high-viscosity food is associated with a variety of physiological responses, one of which is their ability to regulate gastric emptying and modulate postprandial glycemic response. Gastric emptying has been proven to be a key step affecting the digestion and absorption of food, whereas, the relationship between viscosity and gastric emptying is still far away from being understood. Here, we reviewed the factors that influence food viscosity and food viscosity changes during digestion. Besides, the effect of food viscosity on gastric emptying and food-viscosity-physiological response were highlighted. Finally, "quantitative relationship" of viscosity and gastric emptying was discussed. This review can contribute to the understanding that how food viscosity affects gastric emptying, and help for developing foods that could control satiety and manage body weight for the specific populations.

The anti-obesogenic effects of dietary berry fruits: A review

The prevalence of obesity in the world is fearsomely climbing, which has brought about heavy threats on human health and economic development. For coping with this problem, researchers have looked at the profound potentials of natural products for resolving obesity because of their high efficiencies and few undesirable outcomes in the recent years. Berry fruits are huge reservoirs of bioactive components, and their anti-obesity potentials are arousing much interests. In this review, the current main strategies to manage obesity were summarized, including inhibiting appetite and lowering the food intake, improving energy expenditure and thermogenesis, suppressing absorption and digestion, reducing lipid synthesis and storage as well as modulating composition of gut microbiota. In addition, this review discussed the potentials of dietary berry fruits (blueberries, cranberries, raspberries, strawberries, mulberries, lingonberries, blackberries, black chokeberries, elderberries, bilberries, grape, blackcurrants, jaboticabas, red bayberries, sea-buckthorns, goldenberries and goji berries) to counteract obesity or obesity-associated complications based on recent animal experiments and human studies. Then, the bioaccessibility of phenolic compounds present in berry fruits was discussed. On the other hand, several challenges including securing effective dosage, further understanding their interaction with human tissues, improving bioavailability and protection of functional ingredients during delivery should be taken into account and conquered in the coming years.

Contrasting Anti-obesity Effects of Smectite Clays and Mesoporous Silica in Sprague-Dawley Rats

Porous colloids have been shown to exert unique bioactivities for mediating lipid (fat) metabolism and thereby offer significant potential as anti-obesity therapies. In this study, we compare the capacity for two classes of colloids, that is, smectite clays (Laponite XLG, LAP; montmorillonite, MMT) and mesoporous silica (SBA-15 ordered silica; MPS), to impede intestinal lipid hydrolysis and provoke lipid and carbohydrate excretion through adsorption within their particle matrices. A two-stage in vitro gastrointestinal lipolysis model revealed the capacity for both smectite clays and MPS to inhibit the rate and extent of lipase-mediated digestion under simulated fed state conditions. Each system adsorbed more than its own weight of organic media (i.e., lipid and carbohydrates) after 60 min lipolysis, with MMT adsorbing >10% of all available organics through the indiscriminate adsorption of fatty acids and glycerides. When co-administered with a high-fat diet (HFD) to Sprague-Dawley rats, treatment with MMT and MPS significantly reduced normalized rodent weight gain compared to a negative control, validating their potential to restrict energy intake and serve as anti-obesity therapies. However, in vitro-in vivo correlations revealed poor associations between in vitro digestion parameters and normalized weight gain, indicating that additional/alternate anti-obesity mechanisms may exist in vivo, while also highlighting the need for improved in vitro assessment methodologies. Despite this, the current findings emphasize the potential for porous colloids to restrict weight gain and promote anti-obesity effects to subjects exposed to a HFD and should therefore drive the development of next-generation food-grade biomaterials for the treatment and prevention of obesity.

Use of Silica Based Materials as Modulators of the Lipase Catalyzed Hydrolysis of Fats under Simulated Duodenal Conditions

The effect of silica materials and their functionalization in the lipase catalyzed fat hydrolysis has been scarcely studied. Fifteen silica materials were prepared and their effect on the fat hydrolysis was measured, under simulated duodenal conditions, using the pH-stat method. The materials are composed of the combination of three supports (Stöber massive silica nanoparticles, Stöber mesoporous nanoparticles and UVM-7) and four surface functionalizations (methyl, trimethyl, propyl and octyl). In addition, the non-functionalized materials were tested. The functional groups were selected to offer a hydrophobic character to the material improving the interaction with the fat globules and the lipase. The materials are able to modulate the lipase activity and their effect depending on the support topology and the organic covering, being able to increase or reduce the fat hydrolysis. Depending of the material, relative fat hydrolysis rates of 75 to 140% in comparison with absence of the material were obtained. The results were analyzed by Partial Least Square Regression and suggest that the alkyl modified mesopores are able to improve the fat hydrolysis, by contrast the non-porous nanoparticles and the textural pores tend to induce inhibition. The effects are more pronounced for materials containing long alkyl chains and/or in absence of taurodeoxycholate.