The type of fat in the diet determinates the characteristics of gut microbiota, exerting a major role in the development of metabolic syndrome. We hypothesize that a diet enriched with extra virgin olive oil (EVOO) has a distinctive effect on the intestinal microbiome in comparison with an enriched butter diet (BT) and this effect is related to the physiological benefits exerted by EVOO. Swiss Webster mice were fed standard (SD) or two high fat diets enriched with EVOO or butter. Hormonal, physiological and metabolic parameters were evaluated. At the end of the feeding period, DNA was extracted from faeces and the 16S rRNA genes were pyrosequenced. Among the main significant differences found, BT triggered the highest values of systolic blood pressure, correlating positively with the percentage of Desulfovibrio sequences in faeces, which in turn showed significantly higher values in BT than in EVOO. EVOO had the lowest values of plasmatic insulin, correlating inversely with Desulfovibrio, and had the lowest plasmatic values of leptin which correlated inversely with Sutterellaceae, Marispirillum and Mucilaginibacter dageonensis, the three showing significantly higher percentages in EVOO. The lowest total cholesterol levels in plasma were detected in SD, correlating positively with Prevotella and Fusicatenibacter, both taxa with significantly greater presence in SD. These results may be indicative of a link between specific diets, certain physiological parameters and the prevalence of some taxa, supporting the possibility that in some of the proposed effects of virgin olive oil the modulation of intestinal microbiota could be involved.

The metabolic action of oxytocin has recently been intensively studied to assess the ability of the peptide to regulate energy homeostasis. Despite the obvious weight-reducing effect of oxytocin observed in experimental studies, plasma oxytocin levels were found to be unchanged or even elevated in human obesity. The aim of our study was to evaluate the changes in the oxytocin system in Zucker rats, an animal model closely mirroring morbid obesity in humans. Plasma oxytocin levels were measured in obese Zucker rats and lean controls by enzyme immunoassay after plasma extraction. The expression of oxytocin and oxytocin receptor (OXTR) was assessed at the mRNA and protein levels by quantitative real-time PCR and immunoblotting respectively. Plasma and tissue activity of oxytocinase, the main enzyme involved in oxytocin degradation, were measured by fluorometric assay using an arylamide derivate as the substrate. Obese Zucker rats displayed a marked reduction in plasma oxytocin levels. Elevated liver and adipose tissue oxytocinase activity was noticed in obese Zucker rats. Hypothalamic oxytocin gene expression was not altered by the obese phenotype. OXTR mRNA and protein levels were upregulated in the adipose tissue of obese animals in contrast to the reduced OXTR protein levels in skeletal muscle. Our results show that obesity is associated with reduced plasma oxytocin due to increased peptide degradation by liver and adipose tissue rather than changes in hormone synthesis. This study highlights the importance of the oxytocin system in the pathogenesis of obesity and suggests oxytocinase inhibition as a candidate approach in the therapy of obesity.

Extra virgin olive oil (EVOO) has been reported to have a distinct influence on gut microbiota in comparison to other fats, with its physiological benefits widely studied. However, a large proportion of the population consumes olive oil after a depurative process that not only mellows its taste, but also deprives it of polyphenols and other minority components. In this study, we compare the influence on the intestinal microbiota of a diet high in this refined olive oil (ROO) with other fat-enriched diets. Swiss Webster mice were fed standard or a high-fat diet enriched with EVOO, ROO, or butter (BT). Physiological parameters were also evaluated. At the end of the feeding period, DNA was extracted from feces and the 16S rRNA was pyrosequenced. The group fed ROO behaved differently to the EVOO group in half the families with statistically significant differences among the diets, with higher comparative levels in three families—Desulfovibrionaceae, Spiroplasmataceae, and Helicobacteraceae—correlating with total cholesterol. These results are again indicative of a link between specific diets, certain physiological parameters and the prevalence of some taxa, but also support the possibility that polyphenols and minor components of EVOO are involved in some of the proposed effects of this fat through the modulation of the intestinal microbiota

The brain aminopeptidases that participate in the enzymatic cascade of the renin-angiotensin system play a major role in blood pressure (BP) control, and their study offers new perspectives for the understanding of central BP control and the treatment of hypertension. In this system, angiotensin II is converted to angiotensin III (Ang III) by glutamyl aminopeptidase (GluAP) and Ang III is further metabolised to angiotensin IV by alanyl aminopeptidase or arginine-aminopeptidase. It is now clear that Ang III is the key active form of the central angiotensins, exerting tonic stimulatory control over BP Therefore, the development of GluAP inhibitors as potential antihypertensive agents offers new perspectives for therapy. Brain aspartyl JR aminopeptidase, which converts angiotensin I to angiotensin 2-10, is also a possible target for antihypertensive therapy because of its potential role in BP control. Finally, since changes in BP levels, that paralleled changes in brain and plasma aminopeptidase activities, were observed after unilateral lesions of the nigrostriatal system, brain asymmetry, aminopeptidase activities and BP control appear to be related, resulting their interplay in an asymmetrical neuroendocrine response that differentially affect BP control.The study of this interaction may contribute to our understanding of how the brain controls BP

Although the renin-angiotensin system (RAS) is already an old acquaintance, there are often exciting discoveries that improve our knowledge of it and open new therapeutic possibilities. Moreover, well-established drugs, such as angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), or beta-blockers, show that their mechanism of action may be the result of parallel pathways other than the ones initially established. A detailed analysis of the RAS can be carried out in part through the study of the enzymes, named angiotensinases, involved in its cascade, whose activity is a reflection of the functionality of their peptide substrates. The study of these enzymes offers the possibility of controlling the effects of angiotensins through various pharmacological manipulations. For example, angiotensinase inhibitors or activators are being used or have been proposed as antihypertensive agents. They have also been suggested as analgesic and antidepressant drugs or targets for drug development against different pathologies such as Alzheimer's disease, epilepsy or ischemia. On the other hand, the analysis of brain asymmetry has revealed surprising results about the laterality of central and peripheral components of the RAS. Such studies indicate that the neurovisceral integration, already proposed by Claude Bernard (1867) should also be analyzed from a bilateral perspective. In this review, the RAS and the role of various angiotensinases implicated in the cascade are revisited. Therapeutic strategies involving some components of the RAS with an unusual vision resulting from a bilateral perspective added to their study are discussed.