Xanthohumol Requires the Intestinal Microbiota to Improve Glucose Metabolism in Diet-Induced Obese Mice

SCOPE

The polyphenol xanthohumol (XN) improves dysfunctional glucose and lipid metabolism in diet-induced obesity animal models. Because XN changes intestinal microbiota composition, the study hypothesizes that XN requires the microbiota to mediate its benefits.

METHODS AND RESULTS

To test the hypothesis, the study feeds conventional and germ-free male Swiss Webster mice either a low-fat diet (LFD, 10% fat derived calories), a high-fat diet (HFD, 60% fat derived calories), or a high-fat diet supplemented with XN at 60 mg kg-1 body weight per day (HXN) for 10 weeks, and measure parameters of glucose and lipid metabolism. In conventional mice, the study discovers XN supplementation decreases plasma insulin concentrations and improves Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). In germ-free mice, XN supplementation fails to improve these outcomes. Fecal sample 16S rRNA gene sequencing analysis suggests XN supplementation changes microbial composition and dramatically alters the predicted functional capacity of the intestinal microbiota. Furthermore, the intestinal microbiota metabolizes XN into bioactive compounds, including dihydroxanthohumol (DXN), an anti-obesogenic compound with improved bioavailability.

CONCLUSION

XN requires the intestinal microbiota to mediate its benefits, which involves complex diet-host-microbiota interactions with changes in both microbial composition and functional capacity. The study results warrant future metagenomic studies which will provide insight into complex microbe-microbe interactions and diet-host-microbiota interactions.

Serotonin discontinuation syndrome: does it really exist?

Treatment guidelines for depression have typically focused on diagnosis, how to initiate antidepressants, and duration of therapy, while very little is discussed about discontinuing treatment. With the advent of the serotonin-specific reuptake inhibitors (SSRIs), there is now growing evidence to support a "discontinuation syndrome" associated with withdrawal of therapy. This article describes two cases and presents a review of the literature.

Self-assembly of soluble proteins on functionalized lipid layers: a tentative correlation between the fluidity properties of the lipid film and protein ordering

New series of amphiphilic structures are designed to exhibit various fluidity properties when spread at the air-water interface. The influence of the molecular structure of these lipids on the process of two-dimensional (2D) crystallization of the B subunit of DNA gyrase, a soluble protein, is investigated in terms of size of the crystals produced, protein ordering, and crystallization kinetics. Whereas no difference is observed concerning the mean size of the protein 2D crystals obtained on the different lipid supports, the ultimate protein ordering observable by electron microscopy using the negative-staining technique is more regularly attained with some of these new lipids. The most interesting point results from large discrepancies in crystallization kinetics as highly-ordered protein 2D crystals form within 6-24 h depending on the lipid layer structure. Thus, these new lipids reveal of special interest when studying proteins that suffer from extended incubation time at 4 degrees C or higher temperature and lose their functionality.

Synthesis of new fluidity-enhanced amphiphilic compounds for soluble protein two-dimensional crystallization purpose

The synthesis of new amphiphilic compounds is described. The structures are rationally designed for soluble protein two-dimensional (2D) crystallization purpose. Special attention is devoted to fluidity properties expected of resulting monolayers. A series of 13 compounds was prepared containing unsaturated, branched or fluorinated alkyl chains. Structures are either symmetrical or dissymmetrical and present a hydroxyl group as polar head, eventually complemented with two other 'secondary' hydrophilic functions.

Appalachian perspective on modifiable risk factors in coronary artery disease: how well are we doing?

BACKGROUND

Despite recognition of modifiable risk factors and available and effective life-style and pharmacologic therapies, many individuals have unrecognized or untreated risk factors for coronary artery disease.

METHODS

Using MEDLINE, we searched for relevant review articles and clinical trials related to hypertension, hyperlipidemia, diabetes mellitus, smoking, physical activity, obesity, and psychologic risk factors for coronary artery disease. We carefully reviewed the literature and statistics on modifiable risk factors and identified appropriate physician interventions.

RESULTS

A large amount of information is available on coronary artery disease and modifiable risk factors. Much of the data focuses on diagnosis and treatment to goal.

CONCLUSIONS

Coronary artery disease remains the number one cause of death in the United States and West Virginia, even though specific guidelines have been established for detection and treatment. The medical community needs to be more aggressive in managing modifiable risk factors.

Maternal cell contamination in amniotic fluid samples as a consequence of the sampling technique

Maternal cell contamination in amniotic fluid samples is easily detected by in situ hybridization if the karyotype of the fetus differs from the karyotype of the mother. One out of two amniotic fluid samples appears to contain more than 20% maternal cells. Bloody samples often contain even more than 50% maternal cells. Maternal cells can also be identified on the basis of their nuclear morphology. Maternal cell contamination is regularly observed in pregnancies with an anterior placenta, whereas it is rare in posterior placenta pregnancies. The maternal cells are therefore thought to be artificially introduced into the amniotic fluid sample, as a result of placental bleeding during amniocentesis. The implications of maternal cell contamination for prenatal diagnosis using uncultured amniotic fluid samples are discussed.