Efficacy and safety of catheter-based renal denervation for heart failure with reduced ejection fraction: a systematic review and meta-analysis.

PURPOSE: To perform a comprehensive meta-analysis of all available evidence on the efficacy and safety of catheter-based renal denervation for heart failure with reduced ejection fraction. METHODS: We searched English and Chinese databases and calculated the weighted mean difference or standardized mean difference and 95% confidence intervals to estimate the efficacy and safety of renal denervation for heart failure. All relevant studies were screened and a meta-analysis was conducted using Review Manager 5.4. RESULTS: A total of 11 studies were identified for the meta-analysis. For the primary outcomes, the results showed that renal denervation significantly improved ejection fraction (weighted mean difference 6.42), left ventricular end-systolic diameter (weighted mean difference -3.95), left ventricular end-diastolic diameter (weighted mean difference -4.17) and left atrial diameter (weighted mean difference -4.09). For the secondary outcomes, renal denervation reduced the B-type natriuretic peptide level, heart rate, systolic blood pressure and diastolic blood pressure. However, further analysis revealed that renal denervation improved heart function but did not further reduce the heart rate and blood pressure compared with the control group. CONCLUSION: Treatment with renal denervation can significantly improve heart function and structure in patients with heart failure. In addition, the level of B-type natriuretic peptide can be reduced after renal denervation treatment. Renal denervation did not further reduce heart rate and blood pressure compared with the control group. Therefore, the treatment of heart failure with renal denervation is effective and safe.

[Research on improving memory impairment of blue lavender volatile oil].

In order to study the potential application value of lavender volatile oil (LVO), the chemical composition of the volatile oil of lavender was analyzed by GC-MS, and the mouse model of Alzheimer's disease (AD) was established. Additionally, the antioxidant enzymes activity of T-SOD, GSH-PX, CAT and MDA content were studied. Experimental results showed that 55 kinds of chemical constituents including terpene, terpene alcohol and ester compounds from LVO were identified, and the content of linalool and linalyl acetate was the highest, accounting for 49.71% of the total volatile oil. The ability of mouse platform memory was improved significantly. The levels of GSH-PX, CAT and T-SOD of mouse brain tissue in the treatment group were significantly higher than those in the model group (P<0.05). The level of MDA reached the maximum value in the model group, while there was no notable difference between the levels of MDA in the drug group and the normal group. The result indicated the significant oxidative activity of LVO, the possibility of induced oxidative stress reduction in neurons, and the reversal effect of memory acquired disorder.

Mir-24 regulates junctophilin-2 expression in cardiomyocytes.

RATIONALE: Failing cardiomyocytes exhibit decreased efficiency of excitation-contraction (E-C) coupling. The downregulation of junctophilin-2 (JP2), a protein anchoring the sarcoplasmic reticulum to T-tubules, has been identified as a major mechanism underlying the defective E-C coupling. However, the regulatory mechanism of JP2 remains unknown. OBJECTIVE: To determine whether microRNAs regulate JP2 expression. METHODS AND RESULTS: Bioinformatic analysis predicted 2 potential binding sites of miR-24 in the 3'-untranslated regions of JP2 mRNA. Luciferase assays confirmed that miR-24 suppressed JP2 expression by binding to either of these sites. In the aortic stenosis model, miR-24 was upregulated in failing cardiomyocytes. Adenovirus-directed overexpression of miR-24 in cardiomyocytes decreased JP2 expression and reduced Ca(2+) transient amplitude and E-C coupling gain. CONCLUSIONS: MiR-24-mediated suppression of JP2 expression provides a novel molecular mechanism for E-C coupling regulation in heart cells and suggests a new target against heart failure.

Rosuvastatin Enhances Lymphangiogenesis after Myocardial Infarction by Regulating the miRNAs/Vascular Endothelial Growth Factor Receptor 3 (miRNAs/VEGFR3) Pathway.

BACKGROUND: Several clinical studies have suggested that the early administration of statins could reduce the risk of in-hospital mortality in acute myocardial infarction (AMI) patients. Recently, some studies have identified that stimulating lymphangiogenesis after AMI could improve cardiac function by reducing myocardial edema and inflammation. This study aimed to identify the effect of rosuvastatin on postinfarct lymphangiogenesis and to identify the underlying mechanism of this effect. METHOD: Myocardial infarction (MI) was induced by ligation of the left anterior descending coronary artery in mice orally administered rosuvastatin for 7 days. The changes in cardiac function, pathology, and lymphangiogenesis following MI were measured by echocardiography and immunostaining. EdU, Matrigel tube formation, and scratch wound assays were used to evaluate the effect of rosuvastatin on the proliferation, tube formation, and migration of the lymphatic endothelial cell line SVEC4-10. The expression of miR-107-3p, miR-491-5p, and VEGFR3 was measured by polymerase chain reaction (PCR) and Western blotting. A gain-of-function study was performed using miR-107-3p and miR-491-5p mimics. RESULTS: The rosuvastatin-treated mice had a significantly improved ejection fraction and increased lymphatic plexus density 7 days after MI. Rosuvastatin also reduced myocardial edema and inflammatory response after MI. We used a VEGFR3 inhibitor to partially reverse these effects. Rosuvastatin promoted the proliferation, migration, and tube formation of SVEC4-10 cells. PCR and Western blot analyses revealed that rosuvastatin intervention downregulated miR-107-3p and miR-491-5p and promoted VEGFR3 expression. The gain-of-function study showed that miR-107-3p and miR-491-5p could inhibit the proliferation, migration, and tube formation of SVEC4-10 cells. CONCLUSION: Rosuvastatin could improve heart function by promoting lymphangiogenesis after MI by regulating the miRNAs/VEGFR3 pathway.

[A meta-analysis on the safety of combination therapy with fenofibrate and statins].

OBJECTIVE: The aim of this study was to assess the safety of fenofibrate-statin combination therapy. METHODS: Medline, Cochrane Library, Web of Knowledge and CNKI were searched for 2184 randomized controlled trials. Finally, twenty-six studies with a total of 9494 participants were included in this analysis. RESULTS: Compared with statins group, the fenofibrate-statin group had significantly higher incidence of aminotransferase elevations (OR 1.67, 95%CI 1.22-2.30, P < 0.05) . The two groups had identical incidence of creatin kinase elevations (OR 0.86, 95%CI 0.62-1.20, P > 0.05) , muscle-associated adverse events (OR 0.98, 95%CI 0.88-1.09, P > 0.05) and withdrawals due to hepatotoxicity or muscle toxicity. The safety of fenofibrate + standard-dose statin regimens were similar to those in fenofibrate-statin group. CONCLUSION: Combined fenofibrate-statin treatment is generally safe and well tolerated, liver function should be monitored before and during and after therapy.

Endothelial Microparticle-Mediated Transfer of microRNA-19b Inhibits the Function and Distribution of Lymphatic Vessels in Atherosclerotic Mice.

In recent years, the function of the lymphatic system in atherosclerosis has attracted attention due to its role in immune cell trafficking, cholesterol removal from the periphery, and regulation of the inflammatory response. However, knowledge of the mechanisms regulating lymphangiogenesis and lymphatic function in the pathogenesis of atherosclerosis is limited. Endothelial microparticles carrying circulating microRNA (miRNA)s are known to mediate cell-cell communication, and our previous research showed that miRNA-19b in EMPs (EMPmiR-19b) was significantly increased in circulation and atherosclerotic vessels, and this increase in EMPmiR-19b promoted atherosclerosis. The present study investigated whether atherogenic EMPmiR-19b influences pathological changes of the lymphatic system in atherosclerosis. We first verified increased miR-19b levels and loss of lymphatic system function in atherosclerotic mice. Atherogenic western diet-fed ApoE-/- mice were injected with phosphate-buffered saline, EMPs carrying control miRNA (EMPcontrol), or EMPmiR-19b intravenously. The function and distribution of the lymphatic system was assessed via confocal microscopy, Evans blue staining, and pathological analysis. The results showed that lymphatic system dysfunction existed in the early stage of atherosclerosis, and the observed pathological changes persisted at the later stage, companied by an increased microRNA-19b level. In ApoE-/- mice systemically treated with EMPmiR-19b, the distribution, transport function, and permeability of the lymphatic system were significantly inhibited. In vitro experiments showed that miRNA-19b may damage the lymphatic system by inhibiting lymphatic endothelial cell migration and tube formation, and a possible mechanism is the inhibition of transforming growth factor beta receptor type II (TGF-ßRII) expression in lymphatic endothelial cells by miRNA-19b. Together, our findings demonstrate that atherogenic EMPmiR-19b may destroy lymphatic system function in atherosclerotic mice by downregulating TGF-ßRII expression.

Parental Stress as the Mediator Between Symptom Burden and the Quality of Life of Chinese Children With Cancer.

BACKGROUND: Because of their cancer and treatment adverse effects, most pediatric oncology patients will experience 1 or more symptoms at one time that can seriously affect their quality of life. Because these children are attached to parents, their symptom burden directly influences the parental stress level and parental interpretations of their children's quality of life. OBJECTIVE: The aim of this study was to examine the association between child-reported symptom burden and the pediatric quality of life reported by children with cancer and their parents, and whether parental perceived stress mediates these relationships. METHODS: In a cross-sectional design, convenience sampling was used to recruit 80 parent-child dyads. Advanced statistical methods were adopted to analyze the mediating effects of parental stress between children's symptom burden and their quality of life. RESULTS: The results revealed that parental stress was the mediator in the relationship between child-reported symptom burden and children's quality of life reported by parents. The results also showed that parental stress was not a mediator in the relationship between child-reported symptom burden and their quality of life. This underscored the differences in interpretations of quality of life reported by children and their parents. CONCLUSION: Children's symptom burden is an important factor in predicting parental stress level and the quality of life reported by the children. Children's voice should be incorporated whenever possible. IMPLICATIONS FOR PRACTICE: The knowledge gained from this study will facilitate intervention development to enhance parents' abilities in stress management and symptom management for their children with the support of the nursing profession.

Symptom Burden of Children with Cancer and Parental Quality of Life: The Mediating Role of Parental Stress.

BACKGROUND: The aim of this study was to investigate the association between children's reported symptom burden and their parents' quality of life, and whether parents' perceived stress mediates this relationship. METHOD: this was a cross-sectional quantitative research study. Convenience sampling was used to recruit 80 pairs of parents and their children with cancer. Advanced statistical methods were used to analyse the mediating effects of parental stress between children's symptom burden and parents' quality of life. RESULTS: The results showed that parental stress was the mediator in the relationship between children's reported symptom burden and their parents' quality of life. CONCLUSIONS: Symptom burden was prevalent in Chinese children with cancer living in the community. Children's symptom burden is an important factor in predicting parental stress level, which simultaneously and directly lower parents' quality of life. The evidence in this study enlarges the knowledge base about the mediating effect of parental stress on the association between the symptom burden of children with cancer and their parents' quality of life. This evidence is crucial in paving the way for the development of interventions that improve the parental quality of life through stress-reduction programs.

[The roles of microRNA in the diagnosis and therapy for cardiovascular diseases].

Recent years, microRNAs (miRNAs) have attracted scholars' attention extensively. MiRNAs are a class of 21-25-nucleotide non-coding RNAs that have been implicated in regulating gene transcription and expression. Thus, alteration of miRNA is involved in many human activities and diseases. The function of miRNA is varied dependence on cell type and target mRNA. MiRNAs play important roles in the process of injury and repair through affecting cell phenotypes, such as development, division, proliferation, apoptosis and regeneration. Recently, miRNA-based findings seem to be promising implications for diagnosis and therapy.

Therapeutic targets of rosuvastatin on heart failure and associated biological mechanisms: A study of network pharmacology and experimental validation.

To explore the potential targets underlying the effect of rosuvastatin on heart failure (HF) by utilizing a network pharmacology approach and experiments to identify the results. PharmMapper and other databases were mined for information relevant to the prediction of rosuvastatin targets and HF-related targets. Then, the rosuvastatin-HF target gene networks were created in Cytoscape software. Eventually, the targets and enriched pathways were examined by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Furthermore, we constructed an HF animal model and used rosuvastatin to treat them, identifying the changes in heart function and related protein expression. We further used different cells to explore the mechanisms of rosuvastatin. Thirty-five intersection targets indicated the therapeutic targets linked to HF. GO analysis showed that 481 biological processes, 4 cellular components and 23 molecular functions were identified. KEGG analysis showed 13 significant treatment pathways. In animal experiments, rosuvastatin significantly improved the cardiac function of post-myocardial infarction mice and prevented the development of HF after myocardial infarction by inhibiting IL-1Β expression. Cell experiments showed that rosuvastatin could reduce the expression of IL-1B in HUVEC and THP-1 cells. The therapeutic mechanism of rosuvastatin against HF may be closely related to the inhibition of the expression of apoptosis-related proteins, inflammatory factors, and fibrosis-related genes. However, IL-1Β is one of the most important target genes.

[The biological functions of G-quadruplex].

G-quadruplex is a kind of special secondary structure of nuclei acids, which exists in genome DNA and RNA and preferentially located in functional regions such as telomeres, promoters, 5' untranslated region (5' UTR) of mRNA and so on. G-quadruplex has been implicated by a lot of studies as an important structure in many biological processes including gene stability, telomere synthesis, transcriptional or translational regulation of gene expression and recombination. We here review the recent studies of G-quadruplex in genome DNA, RNA and G-quadruplex oligonucleotides, focusing on their biological function.

Progress in exosomes and their potential use in ocular diseases.

Exosomes contain a variety of biological active substances such as proteins, miRNAs, lncRNAs and lipids, and exosomes from different cells play different biological functions. Exosomes, as a carrier, are involved in many pathological processes such as nerve injury and repair, vascular regeneration, immune response, and fibrosis formation. It plays an important role in the treatment of eye diseases such as glaucoma, diabetic retinopathy, and keratitis. This paper reviews the research progress of exosomes in various diseases in vivo, which provides a new way for the treatment of eye diseases.

Physiological and ultrastructural responses of the brown seaweed Undaria pinnatifida to triphenyltin chloride (TPTCL) stress.

Triphenyltin chloride (TPTCL) is a well-known marine pollutant that may constitute major environmental threats to seaweed mariculture. In the present study, the toxic effects of TPTCL on physiology and ultrastructure of cultivated sporophytes of Undaria pinnatifida were investigated under different TPTCL concentrations ranging from 0 to 100 µg L-1. Significant negative effects of increased TPTCL concentration were detected in the relative growth rates, survival percentages and chlorophyll a contents of young and adult sporophytes. Low TPTCL concentrations could significantly stimulate the activities of enzymes related to nitrogen metabolism. The chloroplast, mitochondria and nucleus inside cells were greatly damaged by TPTCL. Meanwhile, significant increases of electron dense deposits and physodes were found. Additionally, young sporophytes exhibited greater tolerance to TPTCL stress than adult sporophytes. The results of this study indicate that coastal TPTCL pollution could reduce the productivity and quality of cultivated U. pinnatifida.

Association between polymorphisms in interleukin-18 promoter and risk of coronary artery disease: a meta-analysis.

BACKGROUND: Previous studies have explored associations between interleukin-18 (IL-18) promoter polymorphisms and coronary artery disease (CAD). However, the results were controversial. We conducted a meta-analysis to clarify the association between the two polymorphisms and CAD risk. METHODS: We searched English and Chinese databases and calculated the odds ratio (OR) and 95% confidence interval (CI) to estimate whether there are genetic associations between IL-18 promoter polymorphisms and the risk of CAD. All relevant studies were screened and meta-analyzed using STATA 15.0. RESULTS: A total of 15 studies, including 12 studies for -137 G/C and 9 studies for -607 C/A, were identified for the meta-analysis. For -137 G/C, the results showed a significantly reduced risk of CAD in the dominant model (OR = 0.85) and heterozygous model (OR = 0.88) in the overall analysis. However, in subgroup analysis, decreased CAD risks were only observed in Asian populations for heterozygous genetic models. For -607 C/A, the overall OR revealed a reduced risk of CAD in all five genetic models (allelic, OR = 0.78; recessive, OR = 0.75; dominant, OR = 0.68; homozygous, OR = 0.61; heterozygous, OR = 0.72). In subgroup analysis, reduced CAD risk was also found in five genetic models of the Asian population. We also found that the IL-18 polymorphisms were correlated with myocardial infarction (MI) and multivessel (MV) disease. CONCLUSION: Our results suggested that the -137 polymorphism and -607 polymorphism in the IL-18 promoter were negatively associated with CAD, especially in the Asian population. In addition, some genetic models were correlated with the severity of CAD.

Effect of Endothelial Microparticles Induced by Hypoxia on Migration and Angiogenesis of Human Umbilical Vein Endothelial Cells by Delivering MicroRNA-19b.

BACKGROUND: Microparticles (MPs) are small extracellular plasma membrane particles shed by activated and apoptotic cells, which are involved in the development of atherosclerosis. Our previous study found that microRNA (miR)-19b encapsulated within endothelial MPs (EMPs) may contribute to the upregulation of circulating miR-19b in unstable angina patients. Hypoxia is involved in atherosclerosis as a critical pathological stimulus. However, it still remains unclear whether the increase of miR-19b levels in EMPs is related to hypoxia and if the effect of miR-19b - wrapped within EMPs - stimulates hypoxia on vascular endothelial cells. This study aimed to explore the changes of miR-19b in EMPs induced by hypoxia as well as their effects on endothelial cells. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured in vitro and arranged to harvest EMPs in two parts: the first part consisted of EMPcontrol and EMPhypoxia and the second part included EMPvehicle, EMPNC mimic, and EMPmiR-19b mimic. Cell migration was detected by scratch migration and transwell chamber migration. Angiogenesis was assessed by tube formation assays. Furthermore, we predicted the target gene of miR-19b by bioinformatics analysis, and luciferase assay was used to verify the targeted gene of miR-19b. Data were analyzed by one-way analysis of variance. Student's t-test was used when two groups were compared. RESULTS: Compared with EMPcontrol- and EMPhypoxia-inhibited migration of cells by scratch migration assay (80.77 ± 1.10 vs. 28.37 ± 1.40, P < 0. 001) and transwell chamber migration assay (83.00 ± 3.46 vs. 235.00 ± 16.52, P < 0.01), the number of tube formations was markedly reduced by 70% in the EMPhypoxia group (P < 0.001) in vitro analysis of HUVECs. Meanwhile, a strong inhibition of migration and tube formation of HUVECs in the presence of miR-19b-enriched EMPmiR-19b mimic was observed. This effect might be due to the delivery of miR-19b in EMPs. Transforming growth factor-ß2 (TGFß2) was predicted to be one of the target genes of miR-19b, and we further confirmed that TGFß2 was a direct target gene of miR-19b using the luciferase assay. The expression of TGFß2 in HUVECs was inhibited by treatment with EMPhypoxia and EMPmiR-19b mimic. CONCLUSIONS: MiR-19b in EMPs induced by hypoxia could reduce endothelial cell migration and angiogenesis by downregulating TGFß2 expression, which may have inhibited the progression of atherosclerosis.

Decreased Intrinsic Functional Connectivity of the Salience Network in Drug-Naïve Patients With Obsessive-Compulsive Disorder.

Obsessive-compulsive disorder (OCD) patients have difficulty in switching between obsessive thought and compulsive behavior, which may be related to the dysfunction of the salience network (SN). However, little is known about the changes in intra- and inter- intrinsic functional connectivity (iFC) of the SN in patients with OCD. In this study, we parceled the SN into 19 subregions and investigated iFC changes for each of these subregions in 40 drug-naïve patients with OCD and 40 healthy controls (HCs) using seed-based functional connectivity resting-state functional magnetic resonance imaging (rs-fMRI). We found that patients with OCD exhibited decreased iFC strength between subregions of the SN, as well as decreased inter-network connectivity between SN and DMN, and ECN. These findings highlight a specific alteration in iFC patterns associated with SN in patients with OCD and provide new insights into the dysfunctional brain organization of the SN in patients with OCD.

Circulating microRNAs as potential biomarkers for unstable angina.

BACKGROUND: Chest pain is a typical presentation in the emergency department (ED), often due to acute coronary syndrome. Accurate and fast identification is crucial. The diagnosis and proper treatment of unstable angina (UA) can reduce the chance of acute myocardial infarction, and reduce high mortality and morbidity rates. However there is a lack of reliable and valid biomarkers in the diagnosis of UA. This study investigated the usefulness of circulating microRNAs (miRNAs) for differentiating UA from non-ischemic chest pain (NICP) in the ED. Methods The expressions of circulating miRNAs in patients with UA were evaluated relative to individuals with NICP (control subjects). Circulating miR-21, miR-25, miR-92a, miR-106b, miR-126* and miR-451 levels were measured in 98 patients with UA and 95 control subjects in the ED. To investigate the underlying functions of miRNAs in UA, bioinformatic analysis of validated miRNAs was conducted. RESULTS: Circulating miRNAs were upregulated in UA compared with the control group. The combination of the modified HEART score (m-HS) and miR-25 (AUC 0.901, NRI 0.096) could better distinguish UA than m-HS alone. Bioinformatic analysis indicated that miRNAs may take part in platelet activation, cGMP-PKG signaling pathways etc. Conclusion: The circulating levels of miRNAs (miR-21, miR-25, miR-106b, miR-126*) are significantly higher in UA patients compared with patients with NICP, and the addition of the m-HS that combined ECG, age, risk factors and troponin is useful to detect or rule out UA. The associated signaling pathways are involved in the pathogenesis of vulnerable plaque.

The changes of gut microbiota after acute myocardial infarction in rats.

Recent studies suggested that gut microbiota was involved in the development of coronary artery disease. However, the changes of gut microbiota following acute myocardial infarction (AMI) remain unknown. In this study, a total of 66 male Wistar rats were randomly divided into control, AMI and SHAM groups. The controls (n = 6) were sacrificed after anesthesia. The AMI model was built by ligation of left anterior descending coronary artery. The rats of AMI and SHAM groups were sacrificed at 12 h, 1 d, 3 d, 7 d and 14 d post-operation respectively. Gut microbiota was analyzed by 16S rDNA high throughput sequencing. The gut barrier injuries were evaluated through histopathology, transmission electron microscope and immunohistochemical staining. The richness of gut microbiota was significantly higher in AMI group than SHAM group at 7 d after AMI (P<0.05). Principal coordinate analysis with unweighted UniFrac distances revealed microbial differences between AMI and SHAM groups at 7 d. The gut barrier impairment was also the most significant at 7 d post-AMI. We further identified the differences of microorganisms between AMI and SHAM group at 7 d. The abundance of Synergistetes phylum, Spirochaetes phylum, Lachnospiraceae family, Syntrophomonadaceae family and Tissierella Soehngenia genus was higher in AMI group compared with SHAM group at 7 d post-operation (q<0.05). Our study showed the changes of gut microbiota at day 7 post AMI which was paralleled with intestinal barrier impairment. We also identified the microbial organisms that contribute most.

Characteristics of elevated cardiac troponin I in patients with acute ischemic stroke.

OBJECTIVE: To study prognostic characteristics of cardiac troponin I (cTnI) elevation in acute ischemic stroke. METHODS: We retrospectively studied patients (n = 248) with acute ischemic stroke, acute ST-segment elevation myocardial infarction, and acute non-ST-elevation myocardial infarction who were treated between January 2013 and October 2015. Baseline demographic data and changes in cTnI levels among these three groups were compared. Patients with acute ischemic stroke were assigned to either the cTnI elevation group (cTnI > 0.034 ng/mL) or the no cTnI elevation group (cTnI ≤ 0.034 ng/mL). Logistic regression analysis was used to identify risk factors associated with elevated serum cTnI in patients with acute ischemic stroke. Moreover, the duration of hospital stay and incidence of major cardiovascular outcomes were compared in patients with acute ischemic stroke, with or without elevated cTnI. RESULTS: In this study population of patients with acute ischemic stroke (n = 178), acute ST-segment elevation myocardial infarction (n = 35), and acute non-ST-elevation myocardial infarction (n = 35), patients with acute ischemic stroke with elevated cTnI comprised 18.5% of subjects. Patients with elevated cTnI were older and more likely to have a history of hypertension. In addition, these patients had higher levels of inflammatory markers, reduced renal functions, increased D-dimer levels, higher NIH stroke scores, and lower left ventricular ejection fractions. Logistic regression analysis showed that both percentage of neutrophil and NIH stroke scores were elevated; estimated glomerular filtration rate and left ventricular ejection fraction were decreased in patients with acute ischemic stroke who had elevated cTnI, and they had more frequent major cardiovascular events during hospital stay. CONCLUSION: Elevated cTnI detected in patients with acute ischemic stroke, indicated a greater likelihood of poor short-term prognosis during hospital stay.

Dietary Capsaicin Improves Glucose Homeostasis and Alters the Gut Microbiota in Obese Diabetic ob/ob Mice.

Background: The effects of capsaicin on obesity and glucose homeostasis are still controversial and the mechanisms underlying these effects remain largely unknown. This study aimed to investigate the potential relationship between the regulation of obesity and glucose homeostasis by dietary capsaicin and the alterations of gut microbiota in obese diabetic ob/ob mice. Methods: The ob/ob mice were subjected to a normal, low-capsaicin (0.01%), or high-capsaicin (0.02%) diet for 6 weeks, respectively. Obesity phenotypes, glucose homeostasis, the gut microbiota structure and composition, short-chain fatty acids, gastrointestinal hormones, and pro-inflammatory cytokines were measured. Results: Both the low- and high-capsaicin diets failed to prevent the increase in body weight, adiposity index, and Lee's obesity index. However, dietary capsaicin at both the low and high doses significantly inhibited the increase of fasting blood glucose and insulin levels. These inhibitory effects were comparable between the two groups. Similarly, dietary capsaicin resulted in remarkable improvement in glucose and insulin tolerance. In addition, neither the low- nor high-capsaicin diet could alter the α-diversity and ß-diversity of the gut microbiota. Taxonomy-based analysis showed that both the low- and high-capsaicin diets, acting in similar ways, significantly increased the Firmicutes/Bacteroidetes ratio at the phylum level as well as increased the Roseburia abundance and decreased the Bacteroides and Parabacteroides abundances at the genus level. Spearman's correlation analysis revealed that the Roseburia abundance was negatively while the Bacteroides and Parabacteroides abundances were positively correlated to the fasting blood glucose level and area under the curve by the oral glucose tolerance test. Finally, the low- and high-capsaicin diets significantly increased the fecal butyrate and plasma total GLP-1 levels, but decreased plasma total ghrelin, TNF-α, IL-1ß, and IL-6 levels as compared with the normal diet. Conclusions: The beneficial effects of dietary capsaicin on glucose homeostasis are likely associated with the alterations of specific bacteria at the genus level. These alterations in bacteria induced by dietary capsaicin contribute to improved glucose homeostasis through increasing short-chain fatty acids, regulating gastrointestinal hormones and inhibiting pro-inflammatory cytokines. However, our results should be interpreted cautiously due to the lower caloric intake at the initial stage after capsaicin diet administration.