Marcelino Montiel-Herrera

Avocado paste (AP) is the main byproduct of industrial avocado processing. It has been recently studied as a source of potentially bioactive compounds with demonstrated in vivo satiety-related actions; however, these have not been explored in human consumers. The present study analyzed the effects of consuming AP-supplemented corn chips (AP-10%) on postprandial glycemia (0, 15, 30, 60, 90, and 120 min post-consumption). Subjective satiety was also analyzed during the aforementioned times, while serum satiety mediators (insulin, glucagon-like peptide-1 [GLP-1], and cholecystokinin [CCK]) and antioxidant capacity were quantified (0 and 120 min post-consumption) in eighteen apparently healthy adult consumers. Maximum glycemia occurred 15 min after consuming the chips (137 mg/dL), which the AP-supplemented samples were able to significantly decrease (118 mg/dL). Subjective satiety was positively affected, as determined by visual analogue scales, which showed that AP-supplemented samples increased the participants’ sensations of satiety and fullness by approximately 28 and 29%, respectively; trends were observed on the concentration of serum satiety mediators, although they were not significant. AP supplementation also mitigated a decrease in postprandial antioxidant capacity, as compared to the control, which showed a significantly lower value, according to the ORAC assay. We conclude that AP-supplemented corn chips may have an impact on postprandial glycemia, subjective satiety, and antioxidant capacity of apparently healthy adult consumers. Further studies are required to determine and/or complement the health effects of prolonged consumption of AP or AP-supplemented products.

Background: Short-chain fatty acids (SCFAs) are metabolites produced by the gut microbiota after fiber fermentation. Some SCFAs, such as acetate, propionate, and butyrate, have been recognized as essential for human health, especially for the brain; however, the cellular mechanisms activated by these molecules in food-intake-related organs, such as the olfactory bulb, remain unclear. Objective: This study evaluates the effects of acetic acid (AA) and sodium butyrate on the physiology of Ca²⁺ metabolism in olfactory bulb cells (OBCs). Methods: Primary OBC cultures of the postnatal rat (P7-21) were made, and Ca²⁺ imaging experiments were performed to record the intracellular Ca²⁺ responses (iCaR) elicited by the application of AA and sodium butyrate (100 nM–1 mM). Immunocytochemical analyses were performed to identify GFAP⁺ cells and GPR41 and GPR43 receptors in OBCs. Endpoint RT-PCR analyses were made to identify GPR41 and GPR43 transcripts in OBCs. Results: Fewer than 10% of the OBCs tested responded to the application of AA and sodium butyrate with iCaR. Pharmacological studies (20 µM 2-aminoethyl diphenylborinate (2-APB); 10 nM GLPG0974, 120 nM AR420626) showed that iCaR were independent of inositol triphosphate (IP₃)-signaling pathways and that OBCs expressed both GPR41 and GPR43 receptors. Endpoint RT-PCR studies performed in both olfactory bulbs and primary OBC cultures confirmed the expression of the GPR41 receptor. Conclusions: This study shows that AA and butyrate induce intracellular Ca²⁺ responses activated by GPR41 and GPR43 receptors in a discrete cellular population of the rat olfactory bulb.

Antioxidants, such as phenolic compounds, are essential for mammal physiology. Significant research made on the gut–brain axis has produced volumes of evidence indicating that some plant-derived phenolic compounds can reach brain cells to exert protective effects on them, mainly by maintaining and/or restoring redox homeostasis. Their systemic uptake and transport might be determined by the phenolic’s physicochemical properties, along with complex interactions with protein transporters and carriers, including GLUT, SGLT1, ABC transporters (P-glycoprotein, breast cancer resistance protein), albumin, fibrinogen, organic anion and cation transporters, and MATE1. The present work focuses on the chemical interactions and transport pathways of some phenolic compounds to reach brain cells.

The development of snake venom-loaded nanobiosystems based on smart biopolymers represents a promising therapeutic approach in several biomedical research fields. Specifically, the western diamondback rattlesnake (Crotalus atrox) contains various bioactive peptides and proteins with reported antitumor activity. This research aimed to establish a simplistic, facile and straightforward protocol for preparing chitosan-g-poly(N-vinylcaprolactam) nanoparticles containing C. atrox venom for potential use as a therapeutic nanocarrier against breast carcinoma cell lines. Herein, the physicochemical properties of venom-loaded nanoparticles were evaluated by FTIR, DLS, and SDS-PAGE. Also, the biological properties of both C. atrox venom and Cs-Venom NPs such as hemagglutination and hemolysis activity were evaluated in vitro. Finally, we evaluated their cytotoxic activity against two breast carcinoma cell lines (T-47D and MDA-MB-231). The most suitable formulation exhibited a hydrodynamic size of 222 nm, a ζ-potential of 42.0 mV and an encapsulation efficiency of 88.6%. C. atrox venom exhibited hemagglutination at concentrations >15 µg/mL but, no hemagglutination or hemolysis was observed for the CS-Venom NPs. Lastly, the IC50 of Cs-Venom NPs was determined for the T-47D and MDA-MB-231 cell lines, at 61.7 and 59.0 µg/mL, respectively. Thus, Cs-Venom NPs exhibit promising properties that can be considered a feasible alternative for developing controlled-release therapeutic systems.

Freshly made, fruit-based beverages may be healthy alternatives to traditional sugar-rich soft drinks due to their reported health benefits. Fruits in general have been reported to promote satiety, but the effects of guava and mamey are yet to be thoroughly studied. The aim of the present work was to document changes in the subjective satiety exerted by a freshly prepared beverage made from guava and mamey pulps in healthy adults, and to compare them with those of a commercial beverage. Eighteen apparently healthy, normoweight, 25–30-year-old individuals (nine men, nine women) participated in this study; their subjective hunger/satiety profile was assessed using 10 cm visual analogue scales. Hunger and prospective food consumption decreased in response to consuming both beverages, while fullness and satisfaction increased. There were no significant differences in any variable analyzed, when comparing the guava and mamey beverage with the control during 120 min following their intake. Likewise, when individually analyzing the responses of men and women, the aforementioned variables remained similar. The participants’ body composition (body fat in particular) appears to be the main anthropometric variable that was significantly associated with their various hunger/satiety responses when consuming both beverages, for both men and women. Our findings therefore suggest that the subjective satiety responses of consuming a freshly prepared guava and mamey beverage are significantly associated with the consumers’ body composition, mainly body fat percentage. More research is needed to determine the precise mechanism by which guava, mamey, and/or their combination can alter satiety in healthy human subjects.

Energy-dense foods are commonly rich in fat and simple sugars and poor in dietary fiber and micronutrients; regularly consuming them decreases the concentration and/or effect of anorexigenic hormones and may increase that of orexigenic ones, thereby decreasing satiety. In contrast, plant-derived phenolic-rich foods exert positive effects on satiety. In silico, in vitro, and in vivo investigations on some of most representative phenolic acids like chlorogenic acid (CGA), gallic acid (GA), ferulic acid (FA), and protocatechuic acid (PCA) have shown that they are able to modulate various hunger and satiety processes; however, there are few studies that show how their chemical structure contributes to achieve such effects. The objective of this review is to summarize how these phenolic acids can favorably modulate hormones and other satiety mediators, with emphasis on the chemical interactions exerted between the core of these compounds and their biological targets. The evidence suggests that they form interactions with certain hormones, their receptors, and/or enzymes involved in regulating hunger and satiety, which are attributed to their chemical structure (such as the position of hydroxyl groups). Further research is needed to continue understanding these molecular mechanisms of action and to utilize the knowledge in the development of health-promoting foods.

El glioblastoma multiforme es un tumor cerebral letal. Los esfuerzos experimentales realizados hasta hoy han mejorado nuestra comprensión sobre la fisiopatología de dicho tumor. Sin embargo, es necesario encontrar objetivos moleculares para identificar vulnerabilidades potenciales y abordar su patogénesis eficientemente. Este trabajo estudió tumores cerebrales de glioblastoma multiforme extirpados de dos pacientes. A través de registros de Ca2+ intracelular in situ e in vitro, RT-PCR de punto final y experimentos histológicos se caracterizó parcialmente el origen de las respuestas de Ca2+ intracelular en células de glioblastoma multiforme humano expuestos a diversas concentraciones extracelulares iónicas y de transmisores químicos. Con ello se encontró que el 70% de las células de glioblastoma multiforme generaron movimientos espontáneos de Ca2+ intracelular, entre los cuales aproximadamente el 9% mostró fluctuaciones rítmicas, incluso en ausencia de calcio y sodio extracelular. Además, los antagonistas de IP3R y SERCA no inhibieron completamente las respuestas de Ca2+ intracelular, mientras que los estudios de RT-PCR mostraron la expresión de S100A9, KCNH1, SLC12A5 y SLC8A1. Estos resultados sugieren la participación de estas proteínas como parte de la maquinaria de señalización celular del glioblastoma multiforme.

Avocado paste (AP) is the main industrial byproduct of its processing, and retains various phenolic compounds (PCs). PCs are known to normalize the plasma lipid profile, but those from avocado byproducts have been minimally studied. We report the normalizing effects of an AP-derived phenolic extract (PE) on the plasma lipid profile of male Wistar rats. A standard (SD) and high-fat diet (HFD) were formulated, and the same diets were supplemented with 1 g/kg of diet of PE (SD + PE and HFD + PE). Rats were fed these diets during an 8-week period. The HFD induced signs of dyslipidemia, but PE treatment countered the decrease in HDL. Relative mRNA expression (real-time PCR) of the hepatic HDL receptor (SCARB1) increased in both groups (SD + PE and HFD + PE), while the LDR receptor (LDLR) increased in SD + PE group. The mRNA expression of apolipoproteins APOA1 and APOB was unaffected. We conclude that PCs from AP can counter a diet-induced decrease in plasma HDL by acting on the mRNA expression of its hepatic receptor.

Classic non-homeostatic structures involved in food intake regulation are reciprocally influenced by metabolic signals. Orexigenic peptides expressed in the olfactory bulb (OB) and hippocampus (HP) modulate olfactory processing and memory, respectively. Hypothalamic circuits also modulate feeding behavior by activating and releasing Agouti-related peptide (AgRP) in response to orexigenic signals. An adequate response to fasting requires the expression of p75 neurotrophin receptor (p75NTR) in AgRP neurons. The present study aimed to determine whether there is a role for p75NTR and AgRP in the OB and HP on the feeding behavior of fasted rats. A group of fasted rats (FG) was confronted with a decision-making paradigm in a T-maze containing a standard chow pellet (CP), and the same pellet coated with a phenolic-rich avocado paste extract (AVO) on either end; their OB and HP were then analyzed with histological and molecular tools. FG rats had briefer feeding latencies, as compared to control rats fed ad libitum (median latencies: 55.4 vs 191.7 min, p = 0.032). They also had reduced cell counts in both brain structures, as compared to satiated rats. AgRP mRNA was not expressed in the HP of either group, however, it was found in the OB. p75NTR mRNA was expressed in both brain structures of FG rats. These results suggest that contrasting metabolic states (fasted or satiated) motivate different feeding responses, which are influenced by p75NTR and AgRP mRNA expression in non-homeostatic food intake brain structures.