Irisin Is Correlated with Blood Pressure in Obstructive Sleep Apnea Patients.

BACKGROUND: Despite approximately 95% primary cases of hypertension, secondary hypertension seems to be common with resistant forms. Notably, obstructive sleep apnea (OSA) is known as a common cause of secondary hypertension and has a major characteristic of obesity. Irisin acts as a link between muscles and adipose tissues in obesity, playing an essential role in human blood pressure (BP) regulation. However, whether irisin is associated with secondary hypertension caused by OSA and how it takes effect essentially have not been elucidated. PURPOSE: To investigate the changes of irisin and its relationship with BP in OSA. METHODS: 72 snoring patients finished Epworth Sleep Scale (ESS) evaluation before polysomnography (PSG). BP was the average of three brachial BP values by mercury sphygmomanometer. Serum irisin level was determined by enzyme-linked immunosorbent assay (ELISA). Results were analyzed by SPSS software. RESULTS: Irisin was higher in the severe and quite severe group than that in control and nonsevere groups (p < 0.05). For BP, significant differences were found between the control group and the other three groups (p < 0.05) and between the quite severe and the other three groups (p ≤ 0.001). Positive correlations were found between irisin and apnea-hypopnea index (AHI), AHI and BP, and irisin level and BP. Negative correlations were between irisin and SpO2 nadir and SpO2 nadir and BP. Positive correlation still existed between AHI and irisin even after adjusting for some obesity-related variables. CONCLUSIONS: Irisin may serve as a potential biomarker for severity of OSA independently of obesity and imply the development of hypertension.

Prevalence and correlates of overweight and obesity among adolescents in northeastern China: a cross-sectional study.

OBJECTIVES: To estimate the prevalence of overweight/obesity among adolescents and evaluate the associated factors in this group in Changchun City in northeastern China. METHODS: A cross-sectional study of 1955 adolescents aged 11-18 years was conducted in Changchun City using stratified cluster sampling. Parents and caregivers of children completed the questionnaires as requested without objection. The questionnaire included demographic characteristics and anthropometric parameters. Univariate and multivariate logistic regression analyses were performed to analyse the relationship between overweight/obesity and related factors. RESULTS: In total, the prevalence of overweight was 12.7% (male 17.4%; female 10.1%) and of obesity was 4.9% (male 8.8%; female 3.1%) in Changchun, Jilin Province. The prevalence of overweight and obesity was higher in boys than in girls (p<0.001). Multivariate logistic regression showed that overweight and obesity were significantly associated with male sex (OR=1.91, 95% CI 1.48 to 2.47), eating fresh fruits more than 2 days per week (OR=1.41, 95% CI 1.09 to 1.84) and eating quickly (OR=1.37, 95% CI 1.06 to 1.78). Students who were not picky (OR=0.69, 95% CI 0.53 to 0.90) were less likely to be overweight, and adolescents whose father was overweight or obese (OR=0.67, 95% CI 0.52 to 0.86) or whose mother was overweight or obese (OR=0.72, 95% CI 0.52 to 0.99) were less likely to be overweight. CONCLUSION: The prevalence of overweight and obesity among adolescents in Changchun has been high in recent years, and the prevalence was higher among boys than among girls. Sex, dietary habits (weekly frequency of fruit consumption, picky eating and slowness in eating) and parental weight were important factors for overweight and obesity in adolescents. Further research should be conducted on the health of adolescents in China, and further intervention measures should be implemented to reduce the prevalence of overweight/obesity.

The alteration of autophagy and apoptosis in the hippocampus of rats with natural aging-dependent cognitive deficits.

AIMS: The present study was aim to explore aging-dependent changes in hippocampal autophagy and apoptosis in a natural aging rat model from adult to old stages and to discover a suitable age for treating neurodegenerative diseases. METHODS: Wistar rats at 5, 18 and 24months of age were used to mimic the adulthood, initial old, and old phases, respectively. The learning and cognitive ability of the rats was detected by the Morris water maze test. Morphological changes in the hippocampus were observed. Expressions of apoptosis and autophagy-related proteins were examined by Western blot. RESULTS: The adult group (5months) exhibited high levels of autophagy related p-ULK p-ULK-1/ULK-1 ratio, Beclin-1, LC3II and cell survival, maintaining normal learning and cognitive function and integrated hippocampal morphology. The initial old group (18 months) presented a reduced number of neurons and cognitive deficits, and exhibited high levels of apoptosis related Bax/Bcl-2 ratio, Caspase-3 activation and autophagy related p-ULK p-ULK-1/ULK-1 ratio, Beclin-1, LC3II compared to the adult group. The old group (24 months) exhibited a high level of apoptosis related Bax/Bcl-2 ratio, Caspase-3 activation and a low level of autophagy related p-ULK p-ULK-1/ULK-1 ratio, Beclin-1, LC3II compared to its younger group, as well as significant neuronal death and cognitive deficits. The degree of autophagy was generally consistent with its negative regulator, the PI3K/Akt/mTOR axis, in all groups. CONCLUSION: Our data suggest that cognitive deficits are first observed in the initial old stage. The levels of autophagy and apoptosis tend to be opposite in the adult and old phases. High levels of autophagy and apoptosis coexist in the initial old stage. Our study indicates that up-regulation of autophagy in the initial old phase to anti-cognitive deficits must be further evaluated.

Adipogenic miR-27a in adipose tissue upregulates macrophage activation via inhibiting PPARγ of insulin resistance induced by high-fat diet-associated obesity.

Chronic low degree inflammation caused by macrophage activation is a crucial factor underlying insulin resistance induced by obesity. To illustrate the mechanism of regulating of macrophage activation in adipose tissue, the role of adipogenic miR-27a activating M1 macrophage polarization via blocking PPARγ was evaluated. Obese mice model and miR-27a overexpression or knockdown mice model were established and related biochemical index were examined. Raw264.7 and 3T3-L1 were cultured and co-cultured for mimicking the microenvironment of local inflammation. Macrophage infiltration was observed. MiR-27a and cytokines levels in serum and adipose tissue were measured. Macrophage polarization markers and protein expression in insulin or inflammatory signaling pathways were observed. Impaired glucose tolerance and insulin tolerance was observed in 4w, 8w and 12w of high fat diet and miR-27a overexpression mice. Concurrently, miR-27a was increased in serum in a time-dependent manner, along with M1 cytokines and M1 macrophages increasing in adipose tissue clearly. Insulin signaling pathway was blocked, and PPARγ was suppressed. However, NF-κB was activated. On the other hand, activated macrophages and hypertrophic adipocytes induced by miR-27a could increase the ratio of Raw264.7 migration, including improving cytokines generation, and blocking PPARγ expression markedly. The present studies are conducted to clarify that miR-27a has increased along with up-regulation in the process of proinflammatory cytokines generation, macrophage influx and M1 macrophage polarization in obesity. These indicate that miR-27a gives the novel target of intervention for inflammation and insulin resistance in obesity.

HNF-4α regulated miR-122 contributes to development of gluconeogenesis and lipid metabolism disorders in Type 2 diabetic mice and in palmitate-treated HepG2 cells.

Hepatocyte Nuclear Factor-4α (HNF-4α) is a key nuclear receptor protein required for liver development. miR-122 is a predominant microRNA expressed in liver and is involved in the regulation of cholesterol and fatty acid metabolism. HNF-4α is know to regulate expression of miR-122 in liver. We examined how HNF-4α regulated gluconeogenesis and lipid metabolism through miR-122 in vivo and in vitro. Expression of miR-122, HNF-4α, phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), sterol response elementary binding protein-1 (SREBP-1), fatty acid synthase-1 (FAS-1), carnitine palmitoyltransferase-1 (CPT-1) and acetyl Coenzyme A carboxylase alpha (ACCα) were determined in livers of Type 2 diabetic mice and in insulin resistant palmitate-treated HepG2 cells. CPT-1 and phosphorylated ACCα expression were significantly decreased in livers of Type 2 diabetic mice and in palmitate-treated HepG2 cells compared to controls. In contrast, expression of miR-122, HNF-4α, PEPCK, G6Pase, SREBP-1, FAS-1 and ACCα were significantly elevated in liver of Type 2 diabetic mice and in palmitate-treated HepG2 cells compared to controls. Expression of HNF-4α increased whereas siRNA knockdown of HNF-4α decreased miR-122 levels in HepG2 cells compared to controls. In addition, expression of HNF-4α in HepG2 cells increased PEPCK, G6Pase, SREBP-1, FAS-1, ACCα mRNA and protein expression and decreased CPT-1 and p-ACCα mRNA and protein expression compared to controls. Addition of miR-122 inhibitors attenuated the HNF-4α mediated effect on expression of these gluconeogenic and lipid metabolism proteins. The results indicate that HNF-4α regulated miR-122 contributes to development of the gluconeogenic and lipid metabolism alterations observed in Type 2 diabetic mice and in palmitate-treated HepG2 cells.

HGSD attenuates neuronal apoptosis through enhancing neuronal autophagy in the brain of diabetic mice: The role of AMP-activated protein kinase.

AIMS: Berberine (BBR) holds promising effect for neuronal injury in diabetes because its anti-apoptotic activity and our laboratory developed the Huang-Gui Solid Dispersion (HGSD) to improve oral bioavailability of BBR. However, anti-apoptotic effect and the mechanism of HGSD in the brain of diabetic mice are not clear. We hypothesized that the AMPK/mTOR signaling pathway could exert a protective role in high glucose induced cellular apoptotic death via inducing autophagy and HGSD could inhibit apoptosis by activating AMPK/mTOR pathway. MAIN METHODS: In vivo, we established C57/BL6 mice diabetic model by STZ and detected apoptosis, autophagy and AMPK/mTOR to explore the effect of HGSD. In vitro, we established high glucose-induced apoptotic death model, treating cells with 3-MA, compound C and AICAR to explore the anti-apoptotic mechanism of BBR. KEY FINDINGS: HGSD significantly inhibited cell apoptosis, enhanced cell autophagy and activated the AMPK/mTOR pathway in the hippocampi of diabetic C57/BL6 mice, and the function of BBR is not obvious at the same dosage. Moreover, BBR significantly attenuated apoptotic death, enhanced autophagy and activated the AMPK/mTOR pathway in high glucose-treated SH-SY5Y cells. Pretreated cells with 3-MA, an inhibitor of autophagy, abolished BBR-inhibited apoptosis. Pretreated cells with Compound C, an AMPK inhibitor, blocked BBR-inhibited apoptotic and BBR-induced cell autophagy. AICAR, an AMPK activator, strengthened the function of BBR. SIGNIFICANCE: HGSD protected against neurotoxicity induced by high glucose through activating autophagy and eventually inhibiting neuronal apoptosis, which was activated by the AMPK/mTOR signaling pathway.

Berberine Attenuates Development of the Hepatic Gluconeogenesis and Lipid Metabolism Disorder in Type 2 Diabetic Mice and in Palmitate-Incubated HepG2 Cells through Suppression of the HNF-4α miR122 Pathway.

Berberine (BBR) has been shown to exhibit protective effects against diabetes and dyslipidemia. Previous studies have indicated that BBR modulates lipid metabolism and inhibits hepatic gluconeogensis by decreasing expression of Hepatocyte Nuclear Factor-4α (HNF-4α). However, the mechanism involved in this process was unknown. In the current study, we examined the mechanism of how BBR attenuates hepatic gluconeogenesis and the lipid metabolism alterations observed in type 2 diabetic (T2D) mice and in palmitate (PA)-incubated HepG2 cells. Treatment with BBR for 4 weeks improve all biochemical parameters compared to T2D mice. Treatment of T2D mice for 4 weeks or treatment of PA-incubated HepG2 cells for 24 h with BBR decreased expression of HNF-4α and the microRNA miR122, the key gluconeogenesis enzymes Phosphoenolpyruvate carboxykinase (PEPCK) and Glucose-6-phosphatase (G6Pase) and the key lipid metabolism proteins Sterol response element binding protein-1 (SREBP-1), Fatty acid synthase-1 (FAS-1) and Acetyl-Coenzyme A carboxylase (ACCα) and increased Carnitine palmitoyltransferase-1(CPT-1) compared to T2D mice or PA-incubated HepG2 cells. Expression of HNF-4α in HepG2 cells increased expression of gluconeogenic and lipid metabolism enzymes and BBR treatment or knock down of miR122 attenuated the effect of HNF-4α expression. In contrast, BBR treatment did not alter expression of gluconeogenic and lipid metabolism enzymes in HepG2 cells with knockdown of HNF-4α. In addition, miR122 mimic increased expression of gluconeogenic and lipid metabolism enzymes in HepG2 cells with knockdown of HNF-4α. These data indicate that miR122 is a critical regulator in the downstream pathway of HNF-4α in the regulation of hepatic gluconeogenesis and lipid metabolism in HepG2 cells. The effect of BBR on hepatic gluconeogenesis and lipid metabolism is mediated through HNF-4α and is regulated downstream of miR122. Our data provide new evidence to support HNF-4α and miR122 regulated hepatic gluconeogenesis and lipid metabolism as promising therapeutic targets for the treatment of T2D.

Ginsenoside Compound K suppresses the hepatic gluconeogenesis via activating adenosine-5'monophosphate kinase: A study in vitro and in vivo.

AIMS: Compound K (CK) is a final intestinal metabolite of protopanaxadiol-type ginsenoside. We have reported that CK presented anti-diabetic effect via diminishing the expressions of hepatic gluconeogenesis key enzyme. Here, we further explore the possible mechanism of CK on suppression hepatic gluconeogenesis via activation of adenosine-5'monophosphate kinase (AMPK) on type 2 diabetes mice in vivo and in HepG2 cells. MAIN METHODS: Type 2 diabetes mice model was developed by high fat diet combined with STZ injection. 30mg/kg/d CK was orally administrated for 4weeks, the fasting blood glucose level and 2h OGTT were conducted, and the protein expression of AMPK, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), Phosphoenolpyruvate carboxykinase (PEPCK) and Glucose-6-phosphatase (G6Pase) were examined. The mechanism of Compound K on hepatic gluconeogenesis was further explored in HepG2 hepatocytes. Glucose production, the protein expression of AMPK, PEPCK, G6pase and PGC-1α, hepatic nuclear factor 4α (HNF-4α) and forkhead transcription factor O1 (FOXO1) were determined after Compound K treatment at the presence of AMPK inhibitor Compound C. KEY FINDINGS: We observed that CK inhibited the expression of PEPCK and G6Pase in the liver and in HepG2 hepatocytes. Meanwhile, CK treatment remarkably increased the activation of AMPK, while decreasing the expressions of PGC-1α, HNF-4α and FOXO1. However, AMPK inhibitor Compound C could reverse these effects of CK on gluconeogenesis in part. SIGNIFICANCE: The results indicated that the effect of CK on suppression hepatic gluconeogenesis might be via the activation the AMPK activity.