Insulin treatment affects leukocyte telomere length in patients with type 2 diabetes: 6-year longitudinal study.

OBJECTIVE: Many studies demonstrated a close relationship between type 2 diabetes mellitus (T2DM) and leukocyte telomere length (LTL). However, how the LTL changes in T2DM and what are the potential causal factors in it, particularly in patients during a long period treatment, have not been studied. Here we performed a longitudinal observation of LTL in trained T2DM patients during a 6-year follow-up and evaluated the possible risk factors that were associated with LTL alteration. METHODS: Seventy-six patients with T2DM were enrolled in this 6-year longitudinal study. The enrolled patients had no severe complication and had never received insulin therapy by the time. Patients were scheduled to visit once every one or two months and their medication changes were recorded. The LTL at the time when patients were enrolled was used as baseline, which was compared with the LTL at 6 year. Multivariable linear regression and exact logistic regression model were adopted to identify independent predictors of telomere length change and telomere length shortening, respectively. RESULTS: Sixty-four patients were successfully followed up. Although mean LTL decreased after 6 years, 30% (19/64) of patients demonstrated LTL lengthening and 70% (45/64) of patients demonstrated LTL shortening. Among them, 18 Patients received insulin treatment during the 6 years. Of these 18 patients, 16 patients showed decreased LTL and only two showed increased LTL. Linear regression analysis demonstrated that change in telomere length during the 6 years was associated inversely with insulin use (ß-coefficients: -0.587, 95% CI: -0.198, -0.085, P < 0.001). Exact logistic regression analysis showed insulin use (OR: 17.355, 95% CI: 2.659, 35.627, P = 0.013) and LDL-C(OR: 3.493, 95% CI: 1.559, 10.063, P = 0.007)were independent predicts of telomere length shortening. CONCLUSIONS: LTL may increase as well as decrease in T2DM who received antidiabetic treatment. Insulin use may accelerate telomere attrition. Insulin use and LDL-C can predict telomere shortening.

Phosphatase and tension homolog overexpression in insulin resistant diabetic adipose tissue.

OBJECTIVE: To investigate the expression of phosphatase and tension homolog (PTEN) in adipose tissue of KKAy diabetic mice, a mouse model of type 2 diabetes. METHODS: KKAy diabetic mice were fed with high fat diet for 4 weeks. After blood glucose met the criteria of diabetes (over 16.7 mmol/L), mice were randomly divided into 3 groups: a control group (without any treatment), a rosiglitazone group (treated with rosiglitazone 12.5 mg/kg.d once per day), and a metformin group (treated with metformin 3 g/kg.d twice daily). After 4 weeks, we then determined the expression of PTEN and phosphoserine 473-Akt (pS473-Akt) in the epididymal adipose tissue with Western blots. The mice in each group were further divided into the insulin (-) subgroup and insulin (+) subgroup, which were intraperitoneally injected with saline and insulin (5 mU/g body weight), respectively. RESULTS: The expression of PTEN was elevated in the epididymal adipose tissue obtained from KKAy diabetic mice compared with that from the C57BL/6J mice (P<0.001). In accordance with the enhanced expression of PTEN, the level of pS473-Akt stimulated by insulin was decreased in the adipose tissue of KKAy mice compared to the C57BL/6J mice (P<0.001). Treatment with the insulin-sensitizing agents, rosiglitazone and metformin did not inhibit the elevated expression of PTEN in adipose tissue of KKAy diabetic mice. CONCLUSION: PTEN may play an important role in the development of insulin resistance in adipose tissue of type 2 diabetes mice model.

Hemoglobinopathy: molecular epidemiological characteristics and health effects on Hakka people in the Meizhou region, southern China.

BACKGROUND: Hemoglobinopathies are the most common inherited diseases in southern China. However, there have been only a few epidemiological studies of hemoglobinopathies in Guangdong province. MATERIALS AND METHODS: Peripheral blood samples were collected from 15299 "healthy" unrelated subjects of dominantly ethnic Hakka in the Meizhou region, on which hemoglobin electrophoresis and routine blood tests were performed. Suspected cases with hemoglobin variants and hereditary persistence of fetal hemoglobin (HPFH) were further characterized by PCR, DNA sequencing, reverse dot blot (RDB) or multiplex ligation-dependent probe amplification (MLPA). In addition, 1743 samples were randomly selected from the 15299 subjects for thalassemia screening, and suspected thalassemia carriers were identified by PCR and RDB. RESULTS: The gene frequency of hemoglobin variants was 0.477% (73/15299). The five main subgroups of the ten hemoglobin variants were Hb E, Hb G-Chinese, Hb Q-Tahiland, Hb New York and Hb J-Bangkok. 277 cases (15.89%, 277/1743) of suspected thalassemia carriers with microcytosis (MCV<82 fl) were found by thalassemia screening, and were tested by a RDB gene chip to reveal a total of 196 mutant chromosomes: including 124 α-thalassemia mutant chromosomes and 72 ß-thalassemia mutant chromosomes. These results give a heterozygote frequency of 11.24% for common α and ß thalassemia in the Hakka population in the Meizhou region. 3 cases of HPFH/δß-thalassemia were found, including 2 cases of Vietnamese HPFH (FPFH-7) and a rare Belgian( G)γ((A)γδß)°-thalassemia identified in Chinese. CONCLUSIONS: Our results provide a detailed prevalence and molecular characterization of hemoglobinopathies in Hakka people of the Meizhou region. The estimated numbers of pregnancies each year in the Meizhou region, in which the fetus would be at risk for ß thalassemia major or intermedia, Bart's hydrops fetalis, and Hb H disease, are 25 (95% CI, 15 to 38), 40 (95% CI, 26 to 57), and 15 (95% CI, 8 to 23), respectively.

G6PD genotype and its associated enzymatic activity in a Chinese population.

Knowledge of the G6PD genotype and its associated enzyme activity is significant for population genetics, diagnosis of disease, and management of patients. We tested 2,872 unrelated subjects from a Hakka population in China for G6PD activity by the WHO standard method and for genotype by DHPLC and DNA sequencing. Among female heterozygotes, 78.5% had relatively normal enzyme activity. The phenotype frequency of G6PD deficiency is 0.028, and the causal allele frequency is 0.060 in females. The accuracy, sensitivity, and specificity of DHPLC are more than 98% for detecting G6PD-deficient hemizygotes, heterozygotes, and homozygotes. Measuring enzyme activity alone is not sufficient for the diagnosis of heterozygotes. A combination of enzyme activity and DNA analysis should be used.

Beneficial effects of a diabetes specific formula on insulin sensitivity and free fatty acid in patients with type 2 diabetes mellitus.

BACKGROUND: This prospective, randomized, controlled study was designed to investigate the effects of a diabetes specific formula (Diason low energy: 313.8 kJ/100 ml), compared with a standard formula, on insulin sensitivity, serum C peptide, serum lipids and free fatty acid (FFA) in type 2 diabetics. METHODS: In total of 71 type 2 diabetics completed the study. Enteral formulas were given orally as the sole source of nutrition to the subjects for 6 days. Venous blood samples (0.5, 1, 2, 3 hours) were collected at day-7 after a 75 g oral glucose tolerance test (OGTT), day 1 after a standard test meal (1673.6 kJ) and after 6 days of either the test diabetes specific formula or a standard formula. Plasma glucose, serum insulin, C peptide and lipids were measured. RESULTS: After the intervention period, the diabetes specific formula resulted in a significantly lower postprandial rise in blood glucose concentrations at 0.5 hour (P < 0.05) and 1 hour (P < 0.01); significantly lower peak height of plasma glucose (P = 0.05); significantly lower plasma insulin concentrations at 0.5 hour (P < 0.01), 1 hour (P < 0.01) and 2 hours (P < 0.01); and a significantly lower plasma insulin peak compared to controls; both OGTT and a standard test meal (P < 0.05). The glucose and insulin area under the curve after the diabetes specific formula compared to the standard formula were significantly lower. The C peptide level was lower after 6 days of both nutrition formulas compare to 75 g OGTT, but not different from the standard mixed meal. Both formulas were well tolerated. CONCLUSIONS: In summary the diabetes specific formula with a relatively high monounsaturated fatty acid and high multi fiber proportion significantly improved glycemic control. On top of this, the insulin sensitivity (HOMA-IS) was significantly improved and may therefore directly improve the impact on long term complications. The disease specific formula should therefore be the preferred option to be used by diabetic and hyperglycemic patients in need of nutritional support.

[The effect of enteral nutritional suspension (diabetes) (TPF-DM) on blood glucose, serum insulin and lipids in patients with type 2 diabetes].

OBJECTIVE: To investigate the effect of a new enteral nutrition suspension (diabetes) (TPF-DM) (Dixson 0.75 kcal/ml) (1 kcal = 4.184 kJ) on blood glucose, serum insulin and lipids as compared with a standard formula (Nutrition MF 0.75 kcal/ml) in patients with type 2 diabetes. METHODS: A randomized, controlled, paralleled and single center trial was carried out. A total of 76 patients with type 2 diabetes without using insulin and obvious complications were randomized into a study group and a control group. 36 patients in the study group and 35 in the control group completed the trial. The observation lasted 6 days. All calories came from enteral nutrition. At baseline all the patients had standard mixed meal (bread 50 g, egg 50 g, milk 250 ml, total calorie 400 kcal) test and at the end of the trial a enteral nutrient meal (enteral nutrient 400 ml, total calorie 300 kcal) test. Blood samples were taken before the meal and 30, 60, 120 and 180 minutes after the meal to test plasma glucose, serum insulin, serum lipids and some safety parameters. The area under curve (AUC) for plasma glucose, serum insulin, serum lipids was calculated. RESULTS: Compared with the mixed meal test, the AUC of plasma glucose and serum insulin during both Dixson 0.75 kcal/ml test and standard formula (Nutrition MF 0.75 kcal/ml) test were significantly lower (P < 0.01). The change at baseline in the study group was more than that in the control group [the change of AUC for plasma glucose (-6.42 +/- 8.62) h x mmol x L(-1) vs (-1.87 +/- 5.30) h x mmol x L(-1), P < 0.01; that of AUC for serum insulin (-36.94 +/- 49.77) h x mIU x L(-1) vs (-18.20 +/- 32.62) h x mIU x L(-1), P < 0.05]. Both the enteral nutrition formula can reduce insulin resistance (calculated by HOMA-IR), but there was no difference between them. There was no significant effect on total cholesterol, high density lipoprotein and low density lipoprotein. AUC of serum triglycerides was lower during the tests with both enteral nutrients than that during mixed meal test, but there was no significant difference between the two groups. There was no safety concern about the enteral nutrition. CONCLUSION: Enteral nutrition suspension (diabetes) (TPF-DM) (Dixson 0.75 kcal/ml) is an effective and safe enteral nutrient to be used in patients with type 2 diabetes.

[Effects of Gymnadenia conopsea alcohol extract on collagen synthesis in rat lungs exposed to silica and its mechanism of antioxidative stress].

OBJECTIVE: To explore the effects of Gymnadenia conopsea alcohol extract (GcAE) on the collagen synthesis in rat lungs exposed to silica and the influence on antioxidase activities, level of lipid peroxidation (LPO). METHODS: One hundred and twenty rats were randomly divided into control group, silica group, and GcAE-treated group. Silicotic animal models were established by direct tracheal instillation of silica into rat lungs surgically. From the second day of model establishment, rats in GcAE-treated group were orally given GcAE [8 g/(kg x d) corresponding to raw herb]. At 7, 14, 21, 28 and 60 days after establishment of the animal model, eight rats in each group were sacrificed, and samples were collected. The malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in plasma were assayed by a spectrophotometer. Types I and III collagen were detected by Sirius red polarization and microscopy, and measuered by Image-Pro Plus Version 4.5 for Windows software. RESULTS: GcAE could reduce the lung/body weight ratio of rats exposed to silica, the synthesis of types I and III collagen of the lungs and the level of lipid peroxidation, increase the activities of SOD and GPx. CONCLUSION: GcAE can ameliorate the silica-induced pulmonary fibrosis by increasing the activities of antioxidase and alleviating the damage of lipid peroxidation to the lungs.

[Identification of G6PD gene variants from Hakka population in Guangdong province].

OBJECTIVE: Studying on G6PD polymorphism from Hakka population in Guangdong province. METHODS: Identifying the variants of G6PD gene and determining the frequencies respectively with the use of amplified refractory mutation system(ARMS), polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) and ABI 3100 DNA sequencing technologies. RESULTS: Mutations of G6PD gene in cDNA 1388 (G-->A), 1376 (G-->T), 95 (A-->G), 392 (G-->T), 1024 (C-->T), 1311 (C-->T) have been found. CONCLUSION: G6PD cDNA 1388 (G-->A), 1376 (G-->T), 95(A--> G), 392 (G-->T), 1024 (C-->T) and 1311 (C-->T) accompanied with intron 11 (93 T-->C) are the common mutations in Chinese population. cDNA 1388 (G-->A), cDNA 1376 (G-->T) are the most popular G6PD gene variants in Hakka population. In this study, no new type of G6PD gene mutation was found in the Hakkas of Guangdong.

[Complex mutations of 1311 C-->T in exon 11 and 93 T-->C in intron 11 in G6PD gene].

OBJECTIVE: To investigate the relationship between complex 1311 mutation of C-->T in exon 11 and 93 T-->C in intron 11 of G6PD gene and the G6PD deficiency. METHODS: Using NBT paper strip method to screen and quantitative NBT method to confirm G6PD deficiency. PCR-SSCP technique was used to find the abnormal exon 11 and the amplification refractory mutation system (ARMS) to identify 1311 mutation, and DNA sequencing to identify the complex mutation at 1311 in exon 11 and 93 in intron 11. RESULTS: Abnormal band in exon 11 was found in 12 cases. DNA sequencing showed that they were 1311 mutation together with 93 mutation. CONCLUSION: This complex mutation may be the cause of reduced activity of G6PD enzyme.