A metagenome-wide association study of gut microbiota in type 2 diabetes.

Assessment and characterization of gut microbiota has become a major research area in human disease, including type 2 diabetes, the most prevalent endocrine disease worldwide. To carry out analysis on gut microbial content in patients with type 2 diabetes, we developed a protocol for a metagenome-wide association study (MGWAS) and undertook a two-stage MGWAS based on deep shotgun sequencing of the gut microbial DNA from 345 Chinese individuals. We identified and validated approximately 60,000 type-2-diabetes-associated markers and established the concept of a metagenomic linkage group, enabling taxonomic species-level analyses. MGWAS analysis showed that patients with type 2 diabetes were characterized by a moderate degree of gut microbial dysbiosis, a decrease in the abundance of some universal butyrate-producing bacteria and an increase in various opportunistic pathogens, as well as an enrichment of other microbial functions conferring sulphate reduction and oxidative stress resistance. An analysis of 23 additional individuals demonstrated that these gut microbial markers might be useful for classifying type 2 diabetes.

Serum TNF-α, GTH and MDA of high-fat diet-induced obesity and obesity resistant rats.

OBJECTIVE: Mechanism of high fat diet-induced obesity is analyzed and serum tumor necrosis factor, malondialdehyde and glutathione levels of obesity resistant rats are effectively analyzed. METHODS: 120 male SD rats were grouped into obesity group and control group, each group with 60 rats. Obese rats were fed with high fat diet, while control rats were fed with ordinary fodder. After six months of feeding, growth degree of two groups of rats is observed , and the rats are divided into obesity group and obesity resistant group based on extent of growth. Then glutathione, tumor necrosis factor-α and MDA content in bat serum are detected with enzyme-linked immunosorbent assay. RESULTS: The content of tumor necrosis factor α in obese rats and obesity resistant rats is far higher than that in control group (P < 0.05), there exists no statistical significance (P > 0.05) in tumor necrosis factor α in obesity group and obesity resistant group, glutathione level of obesity group rats and obesity resistant group rats is significantly increased (P < 0.05) compared with that of control group, and also serum MDA level of the two groups has statistical significance compared with that of normal control group (P < 0.05). CONCLUSION: Among rats fed with high fat diet, in comparison with weight of obesity resistant rats and control group rats, there is no statistically significant difference, (P > 0.05). However, high fat diet will impact mechanisms in vivo in rats, which then induces oxidative stress response and inflammatory response in rats.

[The change of atherogenic index of plasma (AIP) level in type 2 diabetic pedigrees and the response of AIP to Acarbose or Glimepiride in therapy of type 2 diabetes mellitus].

The alterations in atherogenic index of plasma (AlP) in type 2 diabetic patients and their normoglycemic first-degree relatives (NFDR) were investigated, and the effects of Acarbose or Glimepiride on AIP in 99 type 2 diabetic patients were evaluated. Triglycerride (TG), total cholesterol, high density lipoprotein-cholesterol (HDL-C) levels were analyzed, and Log (TG/HDL-C) was calculated as AIP in 62 type 2 diabetic patients and their 67 NFDR from 29 type 2 diabetic pedigrees and in 45 healthy controls without family histories of diabetes. Also analyzed were the same parameters in 99 type 2 diabetic patients before and after therapy with Acarbose or Glimepiride. The results revealed that diabetic patients and their NFDR had significantly higher AIP than did the controls, whereas no significant differences were seen between diabetic patients and their NFDR. Positive correlation of AIP between type 2 diabetic patients and their offspring were observed (r = 0.241, P < 0.05). After 8 weeks therapy with Acarbose, the AIP of type 2 diabetic patients was decreased significantly, and no differences were observed for AIP levels in Glimepiride group although the AIP was lower when compared with the untreated level. As a significant inverse correlation of small dense low density lipoprotein (sdLDL) with AIP was confirmed, our data suggest that diabetic patients and their NFDR from type 2 diabetic pedigrees had significantly higher AIP than did controls; AIP could be decreased by therapy with Acarbose in type 2 diabetic patients; Glimepiride may bring potential benefit to type 2 diabetic patients by influencing sdLDL.

Lipoprotein(a) level and lipids in type 2 diabetic patients and their normoglycemic first-degree relatives in type 2 diabetic pedigrees.

We investigated alterations of serum levels of Lp(a) and lipid profiles in type 2 diabetic patients and their normoglycemic first-degree relatives to evaluate the potential genetic association among these subjects. Serum Lp(a), triglycerride (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein (LDL-C) levels were analyzed in 62 type 2 diabetic patients and 67 normoglycemic first-degree relatives from 29 type 2 diabetic pedigrees, and 45 healthy controls without family histories of diabetes. Dyslipidemia was observed in diabetics and their normoglycemic first-degree relatives. While higher serum TG levels were observed in both type 2 diabetics and their first-degree relatives than those in controls, higher TG levels in diabetics were found when compared with those in first-degree relatives. Meanwhile, lower serum HDL-C levels were observed in both type 2 diabetic patients and their first-degree relatives than those in controls. No significant difference of serum TC and LDL-C levels was found among the three groups. On the other hand, we did not observe significant differences of serum Lp(a) levels between type 2 diabetic patients and normoglycemic first-degree relatives, nor were any significant differences observed between diabetic patients and healthy controls (24.6+/-19.9 vs. 25.8+/-21.2, and 21.3+/-20.5 mg/dl). Although the average serum Lp(a) levels were similar in all subgroups, we did observe a positive correlation of Lp(a) between type 2 diabetic patients and their offspring (r=0.448, P<0.01), suggesting a potential genetic control for Lp(a) levels in type 2 diabetics families.

[Molecular scanning of candidate mtDNA gene fragment in diabetic pedigrees].

OBJECTIVE: To explore novel pathogenic mutation in the mitochondrial DNA gene in diabetic pedigree. METHODS: Twenty-eight suspected mitochondrial DNA diabetic families were recruited. The gene fragment was produced by PCR, and mutation was detected by direct sequencing. RESULTS: In one pedigree, the proband and her mother were found carrying the most common nt3243 A --> G mutation and another 16S rRNA 3205C --> T mutation. But only 3205C --> T was found in her affected brother. All the two patients were deaf and developed diabetes in early age, characterized by impaired beta cell function and low body mass index (BMI). The proband had relatively higher lactic acid concentration than normal individuals. A novel ND1 gene 3434 A --> G(TAT --> TGT) mutation was explored in another proband with deafness and her affected family members. CONCLUSION: 16SrRNA 3205C --> T mutation was found in a mitochondrial diabetes mellitus pedigree, implying its potential pathogenic role in diabetes. Another novel ND1 3434 A --> G mutation was found in another diabetic pedigree. Because this mutation causes amino acid change (Tyr --> Cys) and is co-segregated with diabetes, it may be diabetogenic.

Effect of genetic variants in KCNJ11, ABCC8, PPARG and HNF4A loci on the susceptibility of type 2 diabetes in Chinese Han population.

BACKGROUND: KCNJ11, ABCC8, PPARG, and HNF4A have been found to be associated with type 2 diabetes in populations with different genetic backgrounds. The aim of this study was to test, in a Chinese Han population from Beijing, whether the genetic variants in these four genes were associated with genetic predisposition to type 2 diabetes. METHODS: We studied the association of four representative SNPs in KCNJ11, ABCC8, PPARG, and HNF4A by genotyping them using ABI SNaPshot Multiplex System in 400 unrelated type 2 diabetic patients and 400 unrelated normoglycaemic subjects. RESULTS: rs5219 (E23K) in KCNJ11 was associated with genetic susceptibility to type 2 diabetes (OR = 1.400 with 95% CI 1.117 1.755, P = 0.004 under an additive model, OR = 1.652 with 95% CI 1.086 2.513, P = 0.019 under a recessive model, and OR = 1.521 with 95% CI 1.089 2.123, P = 0.014 under a dominant model) after adjusting for sex and body mass index (BMI). We did not find evidence of association for ABCC8 rs1799854, PPARG rs1801282 (Pro12Ala) and HNF4A rs2144908. Genotype-phenotype correlation analysis revealed that rs1799854 in ABCC8 was associated with 2-hour postprandial insulin secretion (P = 0.005) after adjusting for sex, age and BMI. Although no interactions between the four variants on the risk of type 2 diabetes were detected, the multiplicative interaction between PPARG Pro12Ala and HNF4A rs2144908 was found to be associated with 2-hour postprandial insulin (P = 0.004 under an additive model for rs2144908; and P = 0.001 under a dominant model for rs2144908) after adjusting for age, sex and BMI, assuming a dominant model for PPARG Pro12Ala. CONCLUSIONS: Our study replicated the association of rs5219 in KCNJ11 with type 2 diabetes in Chinese Han population in Beijing. And we also observed that ABCC8 as well as the interaction between PPARG and HNF4A may contribute to post-challenge insulin secretion.