The role of FGF21 in the pathogenesis of cardiovascular disease.

ABSTRACT: The morbidity and mortality of cardiovascular diseases (CVDs) are increasing worldwide and seriously threaten human life and health. Fibroblast growth factor 21 (FGF21), a metabolic regulator, regulates glucose and lipid metabolism and may exert beneficial effects on the cardiovascular system. In recent years, FGF21 has been found to act directly on the cardiovascular system and may be used as an early biomarker of CVDs. The present review highlights the recent progress in understanding the relationship between FGF21 and CVDs including coronary heart disease, myocardial ischemia, cardiomyopathy, and heart failure and also explores the related mechanism of the cardioprotective effect of FGF21. FGF21 plays an important role in the prediction, treatment, and improvement of prognosis in CVDs. This cardioprotective effect of FGF21 may be achieved by preventing endothelial dysfunction and lipid accumulating, inhibiting cardiomyocyte apoptosis and regulating the associated oxidative stress, inflammation and autophagy. In conclusion, FGF21 is a promising target for the treatment of CVDs, however, its clinical application requires further clarification of the precise role of FGF21 in CVDs.

Serum biomarkers combined with ultrasonography for early diagnosis of non-alcoholic fatty liver disease confirmed by magnetic resonance spectroscopy.

Magnetic resonance spectroscopy (MRS) is notably accurate for even minimal degree of hepatic steatosis in non-alcoholic fatty liver disease (NAFLD). But routine use of MRS is limited by its cost and availability. In this study, we developed a diagnostic model combining ultrasonography with biomarkers to identify mild NAFLD, with MRS as the reference standard. A total of 422 eligible subjects were enrolled. The serum levels of fibroblast growth factor 21 (FGF21), cytokeratin 18 M65ED, proteinase 3, neutrophil elastase, alpha-1 antitrypsin, and neutrophil elastase/alpha-1 antitrypsin were measured using ELISA assays. We found that among the six biomarkers, only serum FGF21 was independently associated with intrahepatic triglyceride content (IHTC, standardized ß = 0.185, P < 0.001) and was an independent risk factor for mild NAFLD. Thus, we established a Mild NAFLD Model based on FGF21, alanine transaminase, triglycerides, and body mass index. The area under the receiver-operating characteristic curve of the Mild NAFLD Model was 0.853 (95% confidence interval: 0.816-0.886). Furthermore, a two-step approach combining ultrasonography with the Mild NAFLD Model displayed a better sensitivity for diagnosing mild NAFLD compared with each method alone, with a sensitivity of 97.32% and a negative predictive value of 85.48%. This two-step approach combining ultrasonography and the Mild NAFLD Model derived from serum FGF21 improves the diagnosis of mild NAFLD and can be applied to the early diagnosis of NAFLD in clinical practice.

Predicted secreted protein analysis reveals synaptogenic function of Clstn3 during WAT browning and BAT activation in mice.

Promoting white adipose tissue (WAT) browning and enhancing brown adipose tissue (BAT) activity are attractive therapeutic strategies for obesity and its metabolic complications. Targeting sympathetic innervation in WAT and BAT represents a promising therapeutic concept. However, there are few reports on extracellular microenvironment remodeling, especially changes in nerve terminal connections. Identifying the key molecules mediating the neuro-adipose synaptic junctions is a key point. In this study, we used bioinformatics methods to identify the differentially expressed predicted secreted genes (DEPSGs) during WAT browning and BAT activation. These DEPSGs largely reflect changes of cytokines, extracellular matrix remodeling, vascularization, and adipocyte-neuronal cross-talk. We then performed functional enrichment and cellular distribution specificity analyses. The upregulated and downregulated DEPDGs during WAT browning displayed a distinctive biological pattern and cellular distribution. We listed a cluster of adipocyte-enriched DEPSGs, which might participate in the cross-talk between mature adipocytes and other cells; then identified a synaptogenic adhesion molecule, Clstn3, as the top gene expressed enriched in both mature white and brown adipocytes. Using Q-PCR and immunohistochemistry, we found significantly increased Clstn3 expression level during WAT browning and BAT activation in mice subjected to cold exposure (4 °C). We further demonstrated that treatment with isoproterenol significantly increased Clstn3 and UCP1 expression in differentiated white and beige adipocytes in vitro. In conclusion, our study demonstrates that the secretion pattern was somewhat different between WAT browning and BAT activation. We reveal that Clstn3 may be a key gene mediating the neuro-adipose junction formation or remodeling in WAT browning and BAT activation process.

Synthesis of Mesoporous Yolk-Shell Magnetic Prussian Blue Particles for Multi-Functional Nanomedicine.

Mesoporous magnetic Prussian Blue (PB) particles are good condidates for theragnostic nanomedicine. However, there are lack of efficient methods for fabrication of such materials. Here, we reported the synthesis of the mesoporous yolk-shell Fe3O4@PB particles by one-pot coordination replication and etching. Time-dependent transmission electron microscopy illustrated that the PB crystals nucleated and grew on the surface of Fe3O4 spheres by coordination replication with the help of protons. The extra protons in the reaction medium further disassociated the Fe3O4 and PB, leading to mesoporous particles. The mesoporous yolk-shell Fe3O4@PB particles showed enhanced efficacy for loading cisplatin. The release of the drug molecules could be facilitated by increasing temperature. Both photo irradiation and alternating magnetic fields could trigger the release of heat from the composite. The obtained materials could delivery cisplatin to kill cancer cell intracellularly.

Effect of Dietary Resistant Starch on Prevention and Treatment of Obesity-related Diseases and Its Possible Mechanisms.

Overweight or obesity has become a serious public health problem in the world, scientists are concentrating their efforts on exploring novel ways to treat obesity. Nowadays, the availabilities of bariatric surgery and pharmacotherapy have enhanced obesity treatment, but it should has support from diet, physical exercise and lifestyle modification, especially the functional food. Resistant starch, an indigestible starch, has been studied for years for its beneficial effects on regulating blood glucose level and lipid metabolism. The aim of this review is to summarize the effect of resistant starch on weight loss and the possible mechanisms. According to numerous previous studies it could be concluded that resistant starch can reduce fat accumulation, enhance insulin sensitivity, regulate blood glucose level and lipid metabolism. Recent investigations have focused on the possible associations between resistant starch and incretins as well as gut microbiota. Resistant starch seems to be a promising dietary fiber for the prevention or treatment of obesity and its related diseases.

Fibroblast growth factor 21 is regulated by the IRE1α-XBP1 branch of the unfolded protein response and counteracts endoplasmic reticulum stress-induced hepatic steatosis.

Endoplasmic reticulum (ER) stress activates the adaptive unfolded protein response (UPR) and represents a critical mechanism that underlies metabolic dysfunctions. Fibroblast growth factor 21 (FGF21), a hormone that is predominantly secreted by the liver, exerts a broad range of effects upon the metabolism of carbohydrates and lipids. Although increased circulating levels of FGF21 have been documented in animal models and human subjects with obesity and nonalcoholic fatty liver disease, the functional interconnections between metabolic ER stress and FGF21 are incompletely understood. Here, we report that increased ER stress along with the simultaneous elevation of FGF21 expression were associated with the occurrence of nonalcoholic fatty liver disease both in diet-induced obese mice and human patients. Intraperitoneal administration of the ER stressor tunicamycin in mice resulted in hepatic steatosis, accompanied by activation of the three canonical UPR branches and increased the expression of FGF21. Furthermore, the IRE1α-XBP1 pathway of the UPR could directly activate the transcriptional expression of Fgf21. Administration of recombinant FGF21 in mice alleviated tunicamycin-induced liver steatosis, in parallel with reduced eIF2α-ATF4-CHOP signaling. Taken together, these results suggest that FGF21 is an integral physiological component of the cellular UPR program, which exerts beneficial feedback effects upon lipid metabolism through counteracting ER stress.

One-step hydrothermal synthesis of Fe3O4@C nanoparticles with great performance in biomedicine.

Core-shell structured Fe3O4@C nanoparticles were fabricated by a facile one-pot hydrothermal route. The structure and component of the nanoparticles were fully characterized by transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy, Raman spectroscopy, thermogravimetric analysis, magnetometry and Brunauer-Emmett-Teller specific surface area measurements. The obtained Fe3O4@C nanoparticles possessed favorable dispersibility, high saturation magnetization (61.4 emu g-1) that could quickly respond to external magnetic field and excellent biocompatibility. Excitingly, the experiments of the Fe3O4@C nanoparticles as drug carriers revealed an efficient drug-loading as high as 1.08 mg mg-1. More importantly, the drug loading composite exhibited pH-responsive release profiles and the duration was as long as 200 h; at the pH value of 5.8 and 7.4, the release rate was 93.7% and 33.6%, respectively. Furthermore, the obtained Fe3O4@C nanoparticles had good magneto-thermal ability. All these positive attributes make the as-prepared Fe3O4@C nanoparticles a promising platform for further biomedical evaluations.

Liver enzymes concentrations are closely related to prediabetes: findings of the Shanghai Diabetes Study II (SHDS II).

OBJECTIVE: To investigate the relationship of liver enzymes with hyperglycemia in a large population in Shanghai and identify the association between liver enzymes and insulin resistance. METHODS: A total of 3 756 participants were enrolled. Each participant underwent an oral glucose tolerance test and completed a questionnaire. Anthropometric indices were recorded and serum samples were collected for measurement. RESULTS: Liver enzymes concentrations were independently associated with i-IGT, IFG+IGT, and diabetes. With the increase of ALT and GGT concentrations, ORs for i-IGT, IFG+IGT, and diabetes increased gradually. By comparing patients in the highest quartile of GGT concentrations or ALT concentrations with those in the lowest quartile (Q1), ORs for i-IGT, IFG+IGT, or diabetes was significant after adjustment. Both ALT and GGT concentrations were linearly correlated with HOMA-IR and independently associated with HOMA-IR [ALT OR (95% CI): 2.56 (1.51-4.34) P=0.00; GGT OR (95% CI): 2.66 (1.53-4.65) P=0.00]. CONCLUSION: Serum ALT and GGT concentrations were closely related to pre-diabetes and diabetes in the Shanghai population and positively associated with insulin resistance.

[Association of -6735T-->C variant of glucokinase-associated dual-specificity phosphatase 12 gene with type 2 diabetes in Chinese].

OBJECTIVE: To investigate the impact of glucokinase-associated dual-specificity phosphatase 12 gene (DUSP12) single nucleotide polymorphism (SNP) on type 2 diabetes mellitus in Chinese. METHODS: The genotypes of -6735T-->C of DUSP12 were determined by PCR-RFLP in 577 Chinese in Shanghai, 359 with normal glucose tolerance (NGT) and 218 being newly diagnosed DM patients without taking any drug. Oral glucose tolerance test was conducted. Height, weight, glucose and insulin concentrations, serum lipid profiles, and fat distribution parameters were determined. RESULTS: The genotype frequency distributions of -6735T-->C variant in DUSP12 gene of the DM group and NGT group were not significantly different (all P > 0.05). The fasting plasma glucose concentration of the NGT subjects with C allele was 5.00 (4.69 - 5.28) mmol/L, significantly higher than that of the subjects with TT genotype [4.90 (4.50 - 5.26) mmol/L, P = 0.035]. The serum HDL-c concentration of the NGT subjects with C allele was (1.25 +/- 0.30) mmol/L, significantly lower than that of those with TT genotype [(1.34 +/- 0.30) mmol/L, P = 0.010]. These two results still showed significant statistical differences after adjusted with sex, age, and BMI (P = 0.035). CONCLUSION: -6735T-->C variant in DUSP12 doesn't play a major role in diabetes, but it may have some effects on glucose and lipid metabolism.

Intracellular retention of human melanocortin-4 receptor: a molecular mechanism underlying early-onset obesity in F261S pedigree of Chinese.

OBJECTIVE: To investigate how F261S mutation identified from Chinese obese patients affects the function of melanocortin 4 receptor (MC4R) and to analyze the obesity-related phenotypes in subjects carrying the F261S mutation. METHODS: F261S mutant of MC4R was generated by site-directed mutagenesis. Plasmids encoding wild-type or F261S mutant of MC4R were transfected into HEK293 and COS-7 cells to examine their functional characteristics. Signaling properties of F261S MC4R were assessed by measuring intracellular cAMP levels in response to alpha-MSH stimulation. Cell surface expression of F261S MC4R was compared with that of wild-type MC4R. Clinical examinations were performed in subjects carrying F261S mutation and in non-mutated controls. RESULTS: The alpha-MSH-stimulated reporter gene activity was significantly reduced in cells expressing F261S MC4R, with a maximal response equal to 57% of wild-type MC4R. The F261S mutation also led to a significant change in the Es50 value compared with the wild-type receptor (P<0.01). Immunofluorescent assay revealed a marked reduction in plasma membrane localization of the MC4R in cells expressing the F261S mutant receptor. The resting metabolic rate and fat composition of the mutant carriers were not significantly different from those of the non-mutated obese controls. CONCLUSIONS: The decreased response to alpha-MSH due to the intracellular retention of MC4R may cause early-onset obesity in the F261S pedigree of Chinese.

[Association of variants in APPL1 gene with body fat and its distribution in Chinese patients with type 2 diabetic mellitus].

OBJECTIVE: To investigate the impact of single nucleotide polymorphisms (SNPs) in APPL1 gene on body fat and its distribution. METHODS: 590 unrelated Shanghai residents of Han nationality, including 358 subjects with normal glucose tolerance (NGT) and 232 subjects with type 2 diabetes mellitus (T2DM), underwent measurement of body mass index (BMI), waist circumference (W), hip circumference (H), and femoral circumference (F). Peripheral blood samples were collected to detect the blood sugar, blood lipids, fasting C - peptide (FCP), fasting insulin (FINS), fasting plasma glucose (FGLU), total cholesterol (TC), and triglyceride (TG) 0 and 120 minutes after glucose challenge. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the 2 SNPs (rs3806622 and rs4640525). RESULTS: No differences in the frequencies of rs3806622 and rs4640525 genotypes between the subjects with the BMI < 25 kg/m2 and those with the BMI > or = 25 kg/m2 either in the NGT group or T2DM group. The G allele frequencies of the rs3806622 and rs4640525 genotypes in the T2DM patients with longer W values were significantly higher than those in the patients with shorter W value (OR = 2.26, 95% CI 1.05 - 4.86, and OR = 4.3, 95% CI 1.21 - 14.09). The W values of the T2DM subjects with G alleles were significantly higher than those of the T2DM subjects without G alleles after adjustment of age, sex, and BMI (all P < 0.05). Stepwise regression analysis showed that in addition to sex and BMI, rs4640525 was also an associated factor of waist circumference (all P < 0.05). CONCLUSION: SNPs (rs3806622 and rs4640525) in APPL1 gene are correlated with body fat distribution in T2DM.

[An analysis method to apply linkage disequilibrium maps to association study].

OBJECTIVE: To apply linkage disequilibrium (LD) maps to associations studies with high throughput single nucleotide polymorphisms (SNPs). METHODS: Seven hundred and fifty-four SNPs were genotyped in 160 Shanghai Chinese. LD maps were constructed in cases and controls separately. By comparing the decline of LD unit with distance between the two groups, disease susceptible loci were estimated. This method was compared with traditional analyses including LD analysis, single SNP and haplotype analyses. RESULTS: The analysis of LD maps could detect the chromosome regions with different LD patterns between the cases and controls. The alleles and/or haplotypes frequencies of SNPs within the regions had significantly different distributions or trends of significantly different distributions. CONCLUSION: This method may be applied to analyze the data from association studies with high throughput SNPs genotype information.

Association of a common haplotype of hepatocyte nuclear factor 1alpha with type 2 diabetes in Chinese population.

OBJECTIVE: To analyze the association of variants of hepatocyte nuclear factor-1alpha (HNF-1alpha) gene with type 2 diabetes in Chinese population. METHODS: In 152 unrelated type 2 diabetes patients and 93 unrelated controls, eleven single nucleotide polymorphisms (SNPs) were identified and genotyped. Statistical analyses were performed to investigate whether these SNPs were associated with diabetes status in our samples. RESULTS: In the individual SNP study, no SNP differed significantly in frequency between type 2 diabetes patients and controls. In the haplotype analysis, two haplotype blocks were identified. In haplotype block 1, no evidence was found between common HNF-1alpha haplotypes and type 2 diabetes. However, in haplotype block 2, a common haplotype GCGC formed by four tagging SNPs (tSNPs) was found to be associated with decreased risk of type 2 diabetes (odds ratio [OR] 0.6011, 95% confidence interval [CI] 0.4138-0.8732, P = 0.0073, empirical P = 0.0511, permutation test). A similar trend was also observed in the diplotype analysis, indicating that the increasing copy number of the haplotype GCGC was associated with the decreased frequency of diabetes (P = 0.0193). CONCLUSION: The results of this study provide evidence that the haplotype of HNF-1alpha decreases the risk of type 2 diabetes in Chinese individuals.

[Association between melanocortin 4 receptor gene polymorphisms and obesity].

OBJECTIVE: To investigate the association between the polymorphisms of melanocortin-4 receptor (MC4R) gene and obesity. METHODS: The genotypes of three polymorphisms, nt-216C/T, nt-178A/C, and Val103Ile, were determined through DNA sequencing in 563 Chinese from Shanghai, including 258 individuals with body mass index (BMI) over 30 kg/m(2) and 305 individuals with BMI less than 23 kg/m(2). Height and body weight were measured to calculate BMI. Blood pressure was measured. Waistline, hipline, and femoral waist to calculate the waist-to-hip ratio and waist-to-femoral ratio were measured. Oral glucose tolerance test was conducted to detect the plasma glucose level during fasting condition and 120 minute after glucose loading. The levels of serum lipids, including total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol. RESULTS: (1) The frequencies of nt-216C/T, nt-178A/C, and Val103Ile were all less than 5%. (2) Logistic regression showed that the Val103Ile variant was an independent risk factor for obesity (OR = 0.414, P = 0.040). The frequency of Ile was less in the obese individuals compared with the controls. (3) In the controls and obese individuals, no association was detected between the genotypes and phenotypes. CONCLUSION: Val103Ile variant of MC4R gene is associated with obesity in Chinese.

[Relationship between adiponectin receptor 1 gene -3881T/C variant and glucose metabolism in the Chinese].

OBJECTIVE: To investigate the relationship between adiponectin receptor 1 gene (ADIPOR1) single nucleotide polymorphism (SNP) and glucose metabolism and insulin resistance in the Chinese. METHODS: The genotypes of -3881T/C of ADIPOR1 were determined through polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) in 664 Chinese in Shanghai. Among them, 370 were subjects with normal glucose tolerance and 294 were newly diagnosed diabetic patients without taking any drug. Phenotype measured were: height, weight to calculate body mass index; systolic blood pressure and diastolic blood pressure; plasma glucose level, serum insulin and C-peptide levels of blood obtained both at 0 and 120 minute during a standard 75-gram glucose oral glucose tolerance test. Insulin resistance and beta cell function were assessed by homeostasis model assessment (HOMA-IR and HOMA-B). RESULTS: (1) The frequencies of two alleles did not differ between the type 2 diabetic patients and ones with normal glucose tolerance (P is 0.6749). (2) The frequency of C allele is significantly lower in type 2 diabetic patients with insulin resistance compare with those without insulin resistance (P is 0.0121). (3) In type 2 diabetic patients, the C allele carriers had a significantly lower diastolic blood pressure (P is 0.0466) and HOMA-IR (P is 0.0498). (4) In subjects with normal glucose tolerance, the C allele carriers had a significantly lower fasting plasma glucose (P is 0.0140). CONCLUSION: These findings suggest that variant of ADIPOR1 plays a role in glucose metabolism and insulin resistance in the Chinese.

[Scanning the HNF4A gene mutation from Chinese pedigrees with early- and/or multiple-onset diabetes].

OBJECTIVE: To screen the mutation of hepatocyte nuclear factor 4 alpha gene (HNF4A) in Chinese pedigrees with early and/or multiplex-onset diabetes in Shanghai and nearby area. METHODS: By PCR-single strand conformation polymorphism (PCR-SSCP) and direct sequencing, the mutation screen of HNF4A gene was performed in 93 normal controls and 154 unrelated probands from early- and/or multiplex-onset diabetes. The PCR-RFLP was used to analyze the frequencies of the discovered mutations and variants. RESULTS: Two synonymous mutations (N153N, A158A) were found in two families, of which the N153N was co-segregated with early-onset diabetes. These two synonymous mutations were not detected in the 93 normal controls. Three variants, IVS1+308(A to G)(rs2071197), IVS1+357(A to T)(rs2071198), IVS1-5(C to T)(rs745975), were also identified in this study. The genotype and allele frequencies of the three variants had no difference between the probands and normal controls. CONCLUSION: HNF4A gene mutation is rare in Chinese pedigrees with early and/or multiplex-onset diabetes.

[A novel mutation of WFS1 gene in Chinese patients with Wolfram syndrome].

OBJECTIVE: Wolfram syndrome is an autosomal recessive disorder characterized by early-onset diabetes mellitus, diabetes insipidus, optic atrophy and deafness. The aim of this study was to scan the WFS1 gene mutations in a Chinese Wolfram syndrome pedigree. METHODS: Eight exons and flanking introns of WFS1 gene were screened using PCR-DNA direct sequencing. Effects of the mutation on the structure and function of the WFS1 gene product, Wolframin, were evaluated by bioinformatics. RESULTS: A novel mutation, F417del, in the WFS1 gene was identified. The patient was homozygous of this mutation and the consanguineous parents were heterozygous. The mutation causes the lose of a non-polar amino acid, which was located in the transmembrane domain of the protein product. Bioinformatics predicted that the mutation altered the secondary structure of the transmembrane domain and decreased the hydrophobicity of F417del protein. CONCLUSIONS: This study identified a novel mutation of WFS1 gene and represented the first cause of molecular characterization of Chinese Wolfram syndrome patients.

Effect of polymorphism of uncoupling protein 3 gene -55 (C>T) on the resting energy expenditure, total body fat and regional body fat in Chinese.

OBJECTIVE: To investigate the relationship of the C to T variant at the -55 site of the promoter region of uncoupling protein 3 gene (UCP3) with the resting energy expenditure and the parameters of body fat in Chinese population. METHODS: Three hundred Chinese (91 normal weight subjects, 209 overweight/obesity subjects) were genotyped for the UCP3 gene -55(C>T) by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Resting energy expenditure (REE), fat mass (FM), fat free mass (FFM) and the parameters for regional adipose tissue distribution were measured. RESULTS: Genotype frequencies of UCP3 gene -55(C>T) were not associated with obesity and different types of obesity. The REE level in normal weight subjects with TT homozygotes was higher than that in those with CT heterozygotes and CC homozygotes (P=0.0200). Similar tendency was also observed in overweight/obesity subjects. The FM/FFM exhibited significant difference between the overweight/obesity subjects with a TT genotype and those with a CT or CC genotype (P=0.0096). CONCLUSION: The level of difference in REE caused by the polymorphism of promoter region of UCP3 -55(C>T) may play a role in energy metabolism in Chinese.