Effects of rosiglitazone and metformin on inflammatory markers and adipokines: decrease in interleukin-18 is an independent factor for the improvement of homeostasis model assessment-beta in type 2 diabetes mellitus

OBJECTIVE: We examined the individual pharmacological effects of the addition of rosiglitazone and metformin to glimepiride on inflammatory markers and adipokines in patients with type 2 diabetes mellitus. We analysed the relationships between these variables, the measurements of insulin sensitivity and beta-cell function in patients treated with rosiglitazone plus glimepiride. DESIGN AND PATIENTS: One hundred twenty (120) patients with type 2 diabetes mellitus were randomized and treated with glimepiride plus rosiglitazone or glimepiride plus metformin for 12 weeks. The plasma concentrations of the inflammatory markers and adipokines were measured at baseline and after 12 weeks. MEASUREMENTS: Markers of insulin sensitivity and beta-cell function were determined by the quantitative insulin sensitivity check index (QUICKI) and the homeostasis model assessment of beta-cell function (HOMA-beta), respectively. Plasma concentrations of adiponectin were measured by radioimmunoassay. Plasma concentrations of resistin, tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-18 (IL-18) were measured using ELISA. RESULTS: Improvements in fasting insulin level, QUICKI and HOMA-beta were noted in the rosiglitazone-treated group. Only the QUICKI value improved in the metformin-treated group. Adiponectin concentrations significantly increased in the rosiglitazone-treated group after 12 weeks. Significant decreases in resistin, C-reactive protein, TNF-alpha, IL-6 and IL-18 were seen in the rosiglitazone-treated patients but not in the metformin-treated patients. The independent risk factor for the HOMA-beta change according to stepwise multivariate regression analysis was a change in IL-18. CONCLUSIONS: Rosiglitazone, but not metformin, improved the plasma concentrations of inflammatory markers and adipokines in patients with type 2 diabetes mellitus. A decrease in IL-18 is an independent factor for the improvement of HOMA-beta in type 2 diabetes mellitus.     

Impact of rosiglitazone on beta-cell function, insulin resistance, and adiponectin concentrations: results from a double-blind oral combination study with glimepiride

Addition of rosiglitazone to sulfonylurea has been shown to improve glycemic control in patients with type 2 diabetes previously treated with sulfonylurea monotherapy alone. This investigation was performed to assess the specific impact of rosiglitazone on insulin resistance, beta-cell function, cardiovascular risk markers, and adiponectin secretion in this treatment concept. One hundred two patients from a double-blind, 3-arm comparator trial (group 0, glimepiride + placebo, n = 30; group 4, glimepiride + 4 mg rosiglitazone, n = 31; group 8, glimepiride + 8 mg rosiglitazone, n = 41; 48 women, 54 men; age [mean +/- SD], 62.8 +/- 9.1 years; body mass index, 28.7 +/- 4.5 kg/m2; diabetes duration, 6.4 +/- 4.8 years; HbA1c, 8.1% +/- 1.5%) were analyzed after 0 and 16 weeks of treatment. Observation parameters were HbA1c, glucose, homeostasis model assessment for insulin resistance score, insulin, intact proinsulin, and adiponectin. Insulin resistance was defined by elevated intact proinsulin values or homeostasis model assessment for insulin resistance score of more than 2. All parameters were comparable in the 3 groups at baseline. Substantial and significant dose-dependent improvements were observed after addition of rosiglitazone for fasting glucose (group 0, -9 +/- 48 mg/dL; group 4, -38 +/- 47 mg/dL; group 8, -46 +/- 53 mg/dL), HbA1c (-0.1% +/- 0.7%, -1.1% +/- 1.2%, -1.3% +/- 1.2%), insulin (1.4 +/- 6.2, -1.2 +/- 5.3, -3.7 +/- 9.9 microU/mL), intact proinsulin (1.6 +/- 7.1, -2.0 +/- 4.6, -3.1 +/- 6.1 pmol/L), and high-sensitivity C-reactive protein (0.2 +/- 2.6, -1.7 +/- 3.5, -2.1 +/- 3.5 mg/L). After adjustment for changes in body weight, significant increases in adiponectin were detected with rosiglitazone, whereas glimepiride alone did not induce a comparable effect (-0.5 +/- 5.8, 8.8 +/- 22.9, 14.3 +/- 19.9 mg/L). The number of insulin-resistant patients decreased in both rosiglitazone treatment groups, whereas no change was seen with glimepiride alone. Next to the reported effects on glucose control, rosiglitazone provided an additional beneficial effect on insulin resistance, beta-cell function, and cardiovascular risk markers. In conclusion, our short-term investigation of rosiglitazone action provides further experimental support for the rationale of combining rosiglitazone with sulfonylurea drugs in patients with type 2 diabetes.     

Improvement in C-reactive protein and advanced glycosylation end-products in poorly controlled diabetics is independent of glucose control

We studied the efficacy of four different treatment regimens (sulphonylurea and metformin+/-acarbose versus glimepiride and rosiglitazone versus glimepiride and bedtime NPH insulin versus multiple actrapid and NPH insulin injections) in poorly controlled type 2 diabetes subjects on hs-CRP, VCAM-1 and AGE at 4, 8 and 12 weeks of treatment. Multiple insulin injections rapidly improved HbA(1c) by 0.6+/-0.9% (p<0.005), 1.2+/-1.3% (p<0.0005) and 1.3+/-1.4% (p<0.0005) at week 4, at week 8 and week 12, respectively. Subjects who continued their existing combination treatment of sulphonylurea, metformin+/-acarbose also showed a significant reduction in HbA(1c) (p<0.05). Although effective in reducing glycemic parameters, there was no reduction in CRP levels in either treatment group. The treatment regimen consisting of rosiglitazone and glimepiride significantly lowered hs-CRP by -2.6 (3.9) mg/L (p<0.05) at week 12 in spite of no improvement in blood glucose. AGE improved in all groups irrespective of type of treatment, glycaemic control and CRP levels. Our data indicate rapid glycaemic control alone does not necessarily result in improvement in markers of inflammation in type 2 diabetes patients.     

Rosiglitazone treatment increases plasma levels of adiponectin and decreases levels of resistin in overweight women with PCOS: a randomized placebo-controlled study

OBJECTIVE: Abdominal obesity, insulin resistance and compensatory hyperinsulinaemia play a central role in the pathogenesis of the polycystic ovary syndrome (PCOS). Abdominal adipose tissue is a source of adipokines, such as adiponectin and resistin, both of which may be involved in the development of insulin resistance and chronic inflammation in PCOS. Ghrelin, an important regulatory peptide of food intake, may also play a role in metabolic disturbances related to PCOS. The aim of this study was to examine the effects of 4 months of treatment with the insulin sensitizer rosiglitazone on plasma adiponectin, resistin and ghrelin levels in overweight women with PCOS. DESIGN: A randomised placebo-controlled study. METHODS: Thirty overweight/obese women with PCOS (body mass index>25 kg/m(2), mean age 29.1+/- 1.2 (S.E.M.) years) were randomly allocated to either rosiglitazone (Avandia, 4 mg twice a day) or placebo treatment. Plasma levels of adiponectin, resistin and ghrelin and their correlation to serum levels of insulin, C-peptide and steroid hormones, and insulin sensitivity (euglycaemic hyperinsulinaemic clamp) were assessed. RESULTS: Adiponectin and ghrelin levels correlated significantly with most metabolic markers of insulin resistance and with serum levels of DHEA and 17-hydroxyprogesterone. Plasma levels of adiponectin increased from 9.26+/-0.90 (S.E.M.) to 22.22+/-3.66 microg/ml (P<0.001) and those of resistin decreased from 12.57+/-1.63 to 9.21+/-0.53 ng/ml (P=0.009) at 4 months of treatment, but plasma ghrelin levels did not change. CONCLUSIONS: Rosiglitazone had beneficial effects on serum levels of adiponectin and resistin, suggesting that these adipocytokines may contribute to the improvement in insulin sensitivity observed during the treatment.     

Addition of rosiglitazone to glimepirid and metformin combination therapy in type 2 diabetes

The study was planned to determine the efficacy and safety of adding rosiglitazone to a combination of glimepiride and metformin therapy with insufficiently controlled type 2 diabetes. This was an open-label study with a follow-up period of 26 weeks. Thirty patients were taking 3 mg glimepiride two times and 850 mg metformin two times per day. Patients were told to take one rosiglitazone 4 mg tablet before breakfast additionally. The primary efficacy measure was the mean change in HbA1c from baseline to the end of the study. Secondary efficacy parameters included the mean changes from baseline to the end of the study in fasting plasma glucose (FPG) and insulin levels, as well as total cholesterol, HDL-C, LDL-C, triglycerides, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Mean HbA1c levels decreased significantly from 7.54 +/- 0.9% to 6.57 +/- 0.7% (p < 0.001) at 26th week. FPG levels fell from 169.39 +/- 37.8 mg/dl to 135.69 +/- 28.0 mg/dl (p < 0.001), respectively. Insulin levels decreased from 19.60 +/- 9.8 U/L to 14.66 +/- 11.6 U/L (p = 0.026) at 26th week. No one experienced elevations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels greater than 2.5 times the upper limit of the reference range. This study confirms that the addition of rosiglitazone (4 mg/day) to sulphonylurea and metformin treatment for patients with type 2 diabetes improves glycemic control, is safe, and generally well tolerated.     

Adiponectin--insulin and resistin plasma levels in young healthy offspring of patients with essential hypertension

BACKGROUND: Accumulating epidemiological studies have shown that healthy offspring of hypertensive patients exhibit some metabolic disturbances such as hyperinsulinemia, insulin resistance, lipid disorders, elevated plasma leptin levels and reduced insulin receptor number, features that may be predictors of future cardiovascular events. The aim of this study was to determine insulin, adiponectin and resistin plasma levels in young healthy offspring of patients with essential hypertension, and to compare the findings to those of young healthy offspring of healthy normotensives matched for age, sex and body mass index (BMI). METHODS: Forty-six (24 male/22 female) healthy offspring of patients with essential hypertension-positive family history (FH+), mean age 18+/-3 years and BMI 22.4+/-1.4 kg/m2 (group A) and 50 (28 male/22 female) healthy offspring of healthy normotensives-negative family history (FH-) mean age 18+/-3.2 years and BMI 22.6+/-1.7 kg/m2 (group B) were studied. The two groups were matched for age, sex and BMI. Systolic and diastolic blood pressure (SBP and DBP) measurements, resting heart rate (HR), plasma insulin (RIA method), adiponectin and resistin plasma levels (ELISA) were determined in the whole study population. RESULTS: Mean SBP, DBP and resting HR were significantly higher in group A compared with group B (121+/-13 vs 110+/-10 mmHg, 78+/-6 vs 73+/-8 mmHg, 76+/-4 vs 72+/-6 beats/min, p<0.01, p<0.05 and p<0.01 respectively). Insulin and resistin plasma levels were significantly higher, while adiponectin levels were significantly lower. In group A compared with group B (21+/-7 vs 15+/-6 pIU/ml, 10+/-5 vs 6+/-3 ng/ml, 20+/-5 vs 29+/-8 microg/ml, p<0.01, p<0.01, p<0.01, respectively). CONCLUSION: Our findings suggest that increased SBP, DBP and resting HR as well as increased insulin and resistin plasma levels and decreased adiponectin plasma levels pre-exist in young healthy offspring with positive family history for essential hypertension. Further studies are needed to determine the clinical significance of these observations in attempt to classify these young healthy individuals for future cardiovascular risk.     

Rosiglitazone improves insulin sensitivity in nonobese subjects with impaired glucose tolerance: the role of adiponectin and C-reactive protein

To evaluate the effects of rosiglitazone (ROS) on serum adiponectin and C-reactive protein (CRP) in nonobese subjects with impaired glucose tolerance (IGT), we enrolled 21 patients with body mass index < or =24 kg/m(2) to receive ROS 4 mg daily for 12 weeks. Fifteen age-, sex-, and body mass index-matched healthy subjects were recruited as controls. A 75-g oral glucose tolerance test (OGTT), hemoglobin A(1c), fasting glucose, insulin, C-peptide, lipid profiles, adiponectin, and CRP levels were determined before initiation and at the end of the 12-week ROS treatment. Insulin resistance and beta-cell function were calculated using the homeostasis model assessment method (HOMA-IR and HOMA-beta, respectively). Compared with healthy controls, the ROS-treated subjects had significantly higher glycemic indices, HOMA-IR, CRP, and glucose and insulin concentrations in response to OGTT, and lower HOMA-beta level. After 12 weeks of ROS therapy, the results showed statistically significant changes from baseline in 2-hour plasma glucose during OGTT (9.4 +/- 0.3 vs 8.3 +/- 0.4 mmol/L, P < .05), HOMA-IR (2.6 +/- 0.2 vs 1.9 +/- 0.3, P < .05), HOMA-beta (63.4 +/- 12.5 vs 90.1 +/- 13.0, P < .05), and glucose and insulin concentrations during OGTT in nonobese subjects with IGT. In addition, elevation of serum adiponectin and decrease in CRP levels were significantly found after ROS treatment. Of 21 patients treated with ROS, 5 subjects were converted to normal (converter), 1 progressed to diabetes, and 15 remained in IGT status (nonconverter). There was a significant amelioration in HOMA-IR (-2.10 +/- 1.03 vs -0.07 +/- 0.33, P < .05) without significant changes in adiponectin and CRP levels in converter compared with nonconverter. We conclude that ROS effectively enhanced insulin sensitivity and beta-cell function to improve adiponectin and CRP levels in nonobese patients with IGT. The amelioration of insulin resistance may be a major determinant to predict the conversion of IGT independent of the changes in adiponectin and CRP.     

Effects of pioglitazone and metformin on plasma adiponectin in newly detected type 2 diabetes mellitus

OBJECTIVE: This prospective study evaluates the effect of insulin sensitizers, pioglitazone (PGZ) and metformin (MET) on plasma adiponectin and leptin levels in subjects newly diagnosed with type 2 diabetes mellitus (T2DM). DESIGN: Double blind, randomized, active control, dose escalation study of 12 weeks treatment duration. PATIENTS: Thirty apparently healthy, treatment-naive T2DM patients diagnosed within the past 6 months. MEASUREMENTS: Plasma adiponectin and leptin levels were estimated by enzyme-linked immunosorbent assay (ELISA), and insulin resistance by the homeostasis model of assessment (HOMA-IR). RESULTS: Baseline plasma levels of adiponectin were lower in diabetic (n = 30) subjects than matched controls (n = 10, 6.6 +/- 1.1 vs 10.4 +/- 4.2 microg/ml, P = 0.021). The 12-week treatment with PGZ significantly increased adiponectin concentrations (6.6 +/- 1.1-17.9 +/- 7.4 microg/ml, P < 0.001) with no alteration in the MET treated group (6.8 +/- 1.5-6.7 +/- 2.8 microg/ml, P = 0.9). A significant decrease in plasma leptin levels was observed in the MET treated group (32.0 +/- 28.9-21.4 +/- 23.3 ng/ml, P = 0.024) but not in the PGZ treated group (23.9 +/- 24.1-22.4 +/- 25.4 ng/ml, P = 0.69). The alterations in plasma adiponectin and leptin levels were not associated with any change in body mass index (BMI). PGZ therapy improved insulin sensitivity to a greater degree (P = 0.007 and P = 0.001 for fasting plasma insulin (FPI) and HOMA-IR, respectively) than MET (P = 0.75 and P = 0.02 for FPI and HOMA-IR, respectively) but this improvement was not significantly different from that of MET at the end of 12 weeks (P = 0.146 and P = 0.09 for FPI and HOMA-IR, respectively). However, improvement in insulin sensitivity with PGZ was not commensurate with the increase in adiponectin. Better control of postbreakfast plasma glucose (PBPG) as well as decrease in serum triglycerides (TGs) were also seen with PGZ (PBPG, P < 0.001; TGs, P = 0.013). The rest of the parameters were comparable. Adverse reactions reported were minor and did not result in treatment discontinuation. CONCLUSIONS: Pioglitazone therapy appears to be better in achieving glycaemic control and increasing plasma adiponectin and insulin sensitivity in newly detected type 2 diabetics.     

Differential effect of glimepiride and rosiglitazone on metabolic control of type 2 diabetic patients treated with metformin: a randomized, double-blind, clinical trial

AIM: Accumulating evidence suggests that combination therapy using oral antidiabetic agents with different mechanisms of action may be highly effective in achieving and maintaining target blood glucose levels. The aim of our study is to evaluate the differential effect on glucose and lipid parameters of the association between glimepiride plus metformin and rosiglitazone plus metformin in patients affected by type 2 diabetes and metabolic syndrome. METHODS: Patients were enroled, evaluated and followed at two Italian centres. We evaluated 99 type 2 diabetic patients with metabolic syndrome (48 males and 47 females; 23 males and 24 females, aged 52 +/- 5 with glimepiride; 25 males and 23 females, aged 54 +/- 4 with cglitazone). All were required to have been diagnosed as being diabetic for at least 6 months and did not have glycaemic control with diet and oral hypoglycaemic agents such as sulphonylureas or metformin, both to the maximum tolerated dose. All patients took a fixed dose of metformin, 1500 mg/day. We administered glimepiride (2 mg/day) or rosiglitazone (4 mg/day) in a randomized, controlled, double-blind clinical study. We evaluated body mass index (BMI), glycaemic control, lipid profile [total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol and triglycerides] and lipoprotein parameters [apolipoprotein A-I and apolipoprotein B (Apo B)] during 12 months of this treatment. RESULTS: A total of 95 patients completed the study. Significant BMI decrease was observed at 12 months in glimepiride and rosiglitazone group (p < 0.05 and p < 0.01 respectively) as well as of glycated haemoglobin decrease (p < 0.05 and p < 0.01 respectively), mean fasting plasma glucose and postprandial plasma glucose levels (p < 0.05 and p < 0.01 respectively). A decrease in fasting plasma insulin and postprandial plasma insulin at 12 months (p < 0.05 and p < 0.01 respectively) compared with the baseline value in rosiglitazone group was observed. Furthermore, homeostasis model assessment index improvement was obtained only at 9 and 12 months (p < 0.05 and p < 0.01 respectively) compared with the baseline value in rosiglitazone group. Significant TC, LDL-C and Apo B improvement (p < 0.05 respectively) was present in glimepiride group after 12 months compared with the baseline values, and these variations were significant (p < 0.05) between groups. Of the 95 patients who completed the study, 8.5% of patients in glimepiride group and 12.5% of patients in rosiglitazone group had side-effects (p = not significant). Four patients had transient side-effects in glimepiride group and six patients in rosiglitazone group. Altogether, we did not have statistically significant changes in transaminases. CONCLUSIONS: The rosiglitazone-metformin association significantly improve the long-term control of all insulin-resistance-related parameters in comparison with the glimepiride-metformin-treated group. On the other side, glimepiride treatment is associated to a slight improvement in cholesterolaemia, not observed in the rosiglitazone-treated patients.     

Effects of rosiglitazone and metformin treatment on apelin, visfatin, and ghrelin levels in patients with type 2 diabetes mellitus

Visfatin, ghrelin, and apelin are the most recently identified adipocytokines; but their response to insulin-sensitizing agents is poorly clarified. We aimed to assess the differential effects of either rosiglitazone or metformin monotherapy on the aforementioned adipocytokines in patients with type 2 diabetes mellitus (T2DM). One hundred T2DM patients (30 men, 70 women), with poor glycemic control (glycosylated hemoglobin >6.5%) while taking 850 mg of metformin daily, were enrolled. All participants were randomized to receive either adjunctive therapy with rosiglitazone (8 mg/d, n = 50) or the maximum dose (2550 mg/d) of metformin (MET group, n = 50). Anthropometric parameters, glycemic and lipid profile, high-sensitivity CRP (hs-CRP), insulin resistance (homeostasis model assessment of insulin resistance index [HOMA-IR]), visfatin, ghrelin, and apelin were assessed at baseline and after 14 weeks of therapy. Both rosiglitazone and metformin led to similar, significant improvement in glycemic profile and apelin levels, whereas lipid parameters, fat mass, and visfatin remained almost unaffected (P > .05). Insulin resistance was significantly attenuated in both groups, but to a lesser degree in the MET group (P = .045). Rosiglitazone-treated patients experienced a significant decrease in hs-CRP and systolic blood pressure compared with baseline values and those of the MET group (P < .05). Besides, rosiglitazone treatment considerably increased plasma ghrelin (3.74 ± 1.52 ng/mL) in comparison with either baseline (P = .034) or metformin monotherapy values (−2.23 ± 1.87 ng/mL, P = .008). On the other hand, the MET group, rather than the rosiglitazone group, had decreased body mass index (−0.79 ± 0.47 vs 0.56 kg/m², P = .009). The aforementioned changes in apelin and ghrelin were independently associated with HOMA-IR changes. Both rosiglitazone and metformin favorably changed glycemic indexes and apelin levels. The addition of rosiglitazone seemed to confer greater benefits in ghrelin, hs-CRP, systolic blood pressure, and HOMA-IR regulation than metformin monotherapy. Although these results reflect improvement in cardiovascular risk profile, the overall clinical importance of insulin sensitizers must be further assessed.     

Effects of pioglitazone and metformin on intracellular lipid content in liver and skeletal muscle of individuals with type 2 diabetes mellitus

Both ectopic fat accumulation and changes of the amount of several adipocyte secreting proteins (adipokines) are thought to contribute to the development of insulin resistance associated with obesity and type 2 diabetes mellitus. We have now investigated the effects of 2 insulin-sensitizing drugs, pioglitazone and metformin, on body fat composition and serum adipokine concentrations in individuals with type 2 diabetes mellitus. A total of 41 diabetic patients were treated with pioglitazone (n =21) or metformin (n =20) for 6 months. Intramyocellular lipid content (IMCL) and hepatic lipid content as well as the areas of subcutaneous and visceral fat deposits in the abdomen were determined by nuclear magnetic resonance spectroscopy before and after drug treatment. The serum concentrations of adiponectin and retinol binding protein 4 were also determined by enzyme-linked immunosorbent assays. Pioglitazone treatment reduced both hepatic lipid content (12.0 +/- 6.1 vs 8.4 +/- 3.7 arbitrary units [AU], P < .01) and IMCL (8.4 +/- 3.6 vs 6.3 +/- 2.4 AU/creatine, P < .01), whereas metformin reduced only IMCL (7.0 +/- 3.6 vs 5.8 +/- 2.0 AU/creatine, P < .05). Although the areas of visceral and subcutaneous fat were not significantly affected by treatment with either drug, pioglitazone induced a significant reduction in the ratio of visceral to subcutaneous fat area (0.92 +/- 0.41 vs 0.85 +/- 0.41, P < .05). Pioglitazone treatment also resulted in a marked increase in serum adiponectin concentration (5.6 +/- 4.1 vs 16.2 +/- 9.9 microg/mL, P < .0001) and a small but significant decrease in serum retinol binding protein 4 concentration (73.4 +/- 25.1 vs 65.1 +/- 23.7 microg/mL, P < .05). These results suggest that pioglitazone may improve insulin sensitivity both by affecting serum adipokine concentrations and by reducing the intracellular triglyceride content of liver and skeletal muscle in individuals with type 2 diabetes mellitus.     

Comparative efficacy of glimepiride and/or metformin with insulin in type 2 diabetes

BACKGROUND AND AIMS: The data regarding comparison of efficacy of metformin with glimepiride, newest Sulfonylurea, or with the use of both drugs in combination with insulin is rare in the literature. Therefore, we assessed the daily insulin dose, hypoglycemic events and body weight on achieving desirable glycemic control after addition of insulin, to glimepiride 8 mg and/or metformin 2500 mg, in subjects with type 2 DM manifesting lapse of glycemic control. METHODS: S.C. insulin Novolog Mix [70/30], pre-supper was initiated in 12 subjects on metformin, 14 subjects on glimepiride, and 12 subjects receiving both drugs, with HbA1C > 7.5% and eight subjects receiving placebo. Insulin dose was increased by 4 U at weekly interval until fasting blood sugar [FBS] between 6.6 and 8 mM/l was attained and then further titrated by 2 U every week to attain and maintain FBS between 4.5 and 6.7 mM/l over the next 4 months. The comparisons were conducted between these groups for HbA1C, the daily insulin dose, body weight noted at the end of this study period as well as the hypoglycemic episodes per patient during the last 4 weeks of the study period. RESULTS: HbA1C levels were < 7.0% in all subjects at the end of the study. The daily insulin dose (units), total and per kg/BW was significantly lower [p < 0.001] with metformin (51 +/- 5, 0.51 +/- 0.10), glimepiride (40 +/- 4, 0.42 +/- 0.09) as well as with both drugs (23 +/- 7, 0.21 +/- 0.07) in comparison to placebo (82 +/- 10, 0.82 +/- 0.12). The insulin dose was also significantly lower [p < 0.05] in subjects on both drugs than subjects receiving them individually. Weight gain was less [p < 0.001] with metformin [2.5 +/- 0.74 kg], glimepiride [2.3 +/- 0.7 kg], and both drugs [2.2 +/- 0.61 kg] in comparison to placebo [5.2 +/- 1.4 kg] whereas the hypoglycemic episodes were lesser with metformin (3.8 +/- 1.2) and glimepiride (3.3 +/- 0.9) and least with both drugs (2.5 +/- 0.6) in comparison to placebo (5.2 +/- 1.0). CONCLUSION: Glimepiride and metformin are effective individually in achieving a glycemic goal with a less daily insulin dose, weight gain, and hypoglycemic episodes in comparison to insulin monotherapy in subjects with type 2 diabetes mellitus with further marked reduction in these parameters when used concurrently.     

Effects of rosglitazone on plasma adiponectin, insulin sensitivity, and insulin secretion in high-risk African Americans with impaired glucose tolerance test and type 2 diabetes

We examined the metabolic effects of rosiglitazone therapy on glucose control, insulin sensitivity, insulin secretion, and adiponectin in first-degree relatives of African Americans with type 2 diabetes (DM) with impaired glucose tolerance (IGT) and DM for 3 months. The study was comprised of 12 first-degree relatives with IGT, 17 newly diagnosed DM, and 19 healthy relatives with normal glucose tolerance (NGT). Oral glucose tolerance test (OGTT) was performed before and after 3 months of rosiglitazone therapy (4 to 8 mg/d) in patients with IGT and DM. Serum glucose, insulin, C-peptide, and adiponectin levels were measured before and 2 hours during OGTT in the NGT and patients with IGT and DM. Insulin resistance index (HOMA-IR) and beta-cell function (HOMA-%B) were calculated in each subject using homeostasis model assessment (HOMA). Rosglitazone improved the overall glycemic control in the IGT and DM groups. Following rosiglitazone, the beta-cell secretion remained unchanged, while HOMR-IR was reduced in DM by 30% (4.12 +/- 1.95 v 6.33 +/- 3.54, P < .05) and the IGT group (3.78 +/- 2.45 v 4.81 +/- 3.49, P = not significant [NS]). Mean plasma adiponectin levels were significantly (P < .05) lower in the DM (6.74 +/- 1.95 microg/mL) when compared with the NGT group(9.61 +/- 5.09). Rosiglitazone significantly (P < .001) increased adiponectin levels by 2-fold in patients with IGT (22.2 +/- 10.97 microg/mL) and 2.5-fold greater in DM (15.68 +/- 8.23 microg/mL) at 3 months when compared with the 0 month. We conclude that adiponectin could play a significant role (1) in the pathogenesis of IGT and DM and (2) the beneficial metabolic effects of thiazolidinediones (TZDs) in high-risk African American patients.     

罗格列酮对2型糖尿病患者血清脂肪细胞因子的影响

目的观察罗格列酮（RSG）对2型糖尿病（T2DM）患者血清脂肪细胞因子的影响，探讨血清脂肪细胞因子和胰岛素抵抗（IR）的关系及其在T2DM发病机制中的作用。方法38例新诊断T2DM患者（DM组），以RSG每日4mg口服治疗12周；24例年龄和性别匹配的糖耐量正常者为正常对照（NC）组。检测NC组及DM组患者治疗前后的身高、体重、血压、FPG、2hPG、免疫反应胰岛素（IRI）、真胰岛素（TI）、胰岛素原（PI）、血清脂肪细胞因子瘦素（LEP）、抵抗素（RST）、脂联素（APN）、视黄醇结合蛋白4（RBP-4）、尿白蛋白（UAlb）和血脂谱。计算BMI、胰岛素敏感性指数（QUICKI）、胰岛素抵抗指数（HOMA-IR）和FPI／FTI。结果DM组RSG治疗前PG、IRI、FPI、LEP、RST、RBP-4、HOMA-IR和FPI／FTI均较NC组升高，而APN和QUICK下降（P〈0．05）；DM组RSG治疗后，BMI、UAlb、血脂谱和RBP-4无显著变化，其余指标均向正常转化，APN则升高达2倍多（P〈0．01）。LEP与性别、BMI、FIRI、FTI、FPI、HOMA-IR和QUICKI相关；RST与FPI／FTI和TI相关；APN与年龄、BMI、RBP-4、FPI、2hPI、FTI、HOMA-IR和QuICKI相关；RBP-4与BMI、APN、HOMA-IR相关。多元逐步回归分析提示，LEP和APN与IR独立相关。结论新诊断T2DM患者存在IR和血清LEP、RST、RBP-4升高；APN下降；RSG可能通过改善血清脂肪细胞因子谱而发挥降血糖、改善IR和口细胞功能的疗效。     

Direct comparison among oral hypoglycemic agents and their association with insulin resistance evaluated by euglycemic hyperinsulinemic clamp: the 60's study

The aim of the study was to compare the long-term effect of 4 antidiabetic treatment protocols on insulin resistance evaluated by euglycemic hyperinsulinemic clamp in type 2 diabetes mellitus patients. Two hundred seventy-one type 2 diabetes mellitus patients with poor glycemic control and who were overweight were enrolled in this study. Patients were randomized and titrated to take pioglitazone, metformin, pioglitazone + metformin, or glimepiride + metformin for 15 months. They underwent a euglycemic hyperinsulinemic clamp at baseline, after 3 months, and after 15 months. Anthropometric and metabolic measurements were assessed at baseline, after 3 months, and after 15 months. There was a decrease in glycated hemoglobin in all groups, but glycated hemoglobin value was lower in the group treated with pioglitazone + metformin compared with the groups treated with metformin alone and with pioglitazone alone. There was a decrease in fasting plasma glucose and postprandial plasma glucose values in all groups, but values obtained with pioglitazone + metformin were lower compared with values in the groups treated with metformin alone and with pioglitazone alone. Fasting plasma insulin and postprandial plasma insulin values were higher in the group treated with glimepiride + metformin compared with the other groups. After 15 months, glucose infusion rate and total glucose requirement values observed in the groups treated with pioglitazone alone and with pioglitazone + metformin were higher compared with the values in the group treated with metformin alone and with glimepiride + metformin; furthermore, values obtained in the group treated with pioglitazone + metformin were higher than the value obtained with pioglitazone alone. Pioglitazone-metformin-based therapeutic control is associated with the most quantitatively relevant improvement in insulin resistance-related parameters, whereas the sulfonylurea-metformin-including protocol has less relevant effects.     

Effect of metformin treatment on multiple cardiovascular disease risk factors in patients with type 2 diabetes mellitus

In light of the conflicting results of the recent United Kingdom Prospective Study (UKPDS), where diabetic patients on metformin monotherapy had lower all-cause mortality and the addition of metformin in sulfonylurea-treated patients was associated with an increased risk of diabetes-related death, we sought to compare the effects on cardiovascular disease (CVD) risk factors of metformin monotherapy with metformin treatment when added to a sulfonylurea compound in patients with type 2 diabetes. Thirty-one volunteers with type 2 diabetes mellitus, 16 on dietary therapy and 15 on sulfonylurea monotherapy (SU), were treated with metformin for 12 weeks. Measurements were made of (1) fasting plasma glucose, hemoglobin A(1c) (HbA(1c)), lipid, remnant lipoprotein cholesterol (RLP-C) levels, and low-density lipoprotein (LDL) particle size; (2) daylong plasma glucose, insulin, free fatty acid (FFA), triglyceride (TG), and RLP-C concentrations; and (3) fasting levels of soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble E-selectin (sE-selectin). Fasting plasma glucose concentrations decreased to a similar degree after treatment with metformin in both the metformin monotherapy group (12.45 +/- 0.48 v 9.46 +/- 0.47 mmol/L, P <.001) and the combined SU and metformin therapy group (14.09 +/- 0.51 v 10.57 +/- 0.85 mmol/L, P =.001). Fasting plasma lipid concentrations and LDL particle size did not significantly change in either treatment group, whereas fasting RLP-C concentrations were significantly lower in the metformin monotherapy group (0.43 +/- 0.09 v 0.34 +/- 0.07 mmol/L, P =.02). Daylong concentrations of plasma glucose, FFA, TG, and RLP-C were lower to a similar degree in both treatment groups, whereas daylong plasma insulin concentrations were unchanged. Fasting plasma sVCAM-1 levels were significantly lower in both the metformin monotherapy group (484 +/- 19 v 446 +/- 18 ng/mL, P =.02) and the combined SU and metformin therapy group (496 +/- 29 v 456 +/- 31 ng/mL, P =.05), whereas fasting plasma sICAM-1 and sE-selectin levels were essentially unchanged. Administration of metformin, either as monotherapy or in combination with a sulfonylurea drug, improved glycemic control and led to a decrease in several CVD risk factors in patients with type 2 diabetes.     

Glycemic control with glyburide/metformin tablets in combination with rosiglitazone in patients with type 2 diabetes: a randomized, double-blind trial

PURPOSE: To assess the efficacy and safety of adding rosiglitazone to an established regimen of glyburide/metformin in patients with type 2 diabetes who had not achieved adequate glycemic control (glycosylated hemoglobin [HbA1C] levels >7.0% and < or =10.0%). METHODS: Following an open-label, lead-in phase to optimize the dosing of glyburide/metformin tablets, 365 patients randomly received additive therapy comprising rosiglitazone (4 mg once daily) or placebo for 24 weeks. Based on glycemic response, rosiglitazone dose was maintained or increased to 4 mg twice daily. Glyburide/metformin dose was maintained or reduced by 2.5/500 mg for symptomatic hypoglycemia. The primary endpoint was the change in HbA1C level from baseline to week 24. The proportions of patients achieving HbA1C levels <7% and a fasting plasma glucose level <126 mg/dL were also assessed. RESULTS: After 24 weeks, therapy with glyburide/metformin plus rosiglitazone resulted in a greater reduction in HbA1C levels (-1.0%, P<0.001) compared with combination therapy that included placebo, and in a larger proportion of patients (42% vs. 14%) who attained levels <7%. The difference in fasting plasma glucose levels between groups was -48 mg/dL (P<0.001), favoring glyburide/metformin plus rosiglitazone. The adverse event profile in the rosiglitazone-treated group included mild-to-moderate edema (8%), hypoglycemia (22%), and weight gain of 3 kg. No patient experienced hypoglycemia requiring third-party assistance. CONCLUSION: In patients with inadequate glycemic control despite established glyburide/metformin therapy, the addition of rosiglitazone improves glycemic control, allowing more patients to achieve an HbA1C level <7% and perhaps delaying the need for insulin treatment.     

Exercise training ameliorates the effects of rosiglitazone on traditional and novel cardiovascular risk factors in patients with type 2 diabetes mellitus

The aim of the study was to investigate the effects of rosiglitazone and/or exercise training on novel cardiovascular risk factors in patients with type 2 diabetes mellitus. One hundred overweight/obese type 2 diabetes mellitus patients, with inadequate glycemic control (hemoglobin A_1c >7%) despite combined treatment with gliclazide plus metformin, were randomized using a 2 × 2 factorial design to 4 equivalent (n = 25) groups, as follows: (1) CO: maintenance of habitual activities, (2) RSG: add-on therapy with rosiglitazone (8 mg/d), (3) EX: adjunctive exercise training, and (4) RSG + EX: supplementary administration of rosiglitazone (8 mg/d) plus exercise training. No participant had diabetic vascular complications or was receiving lipid-lowering therapy. Anthropometric parameters, cardiorespiratory capacity, glycemic and lipid profile, apolipoprotein (apo) A-I, apo B, interleukin (IL)-10, IL-18, insulin resistance, and blood pressure were measured before and after 12 months of intervention (P < .05). Both RSG and EX groups significantly reduced glycemic indexes, insulin resistance, blood pressure, and IL-18, whereas they significantly increased high-density lipoprotein, cardiorespiratory capacity, and IL-10, compared with CO group (P < .05). Besides this, exercise-treated patients conferred a remarkable down-regulation in the rest of lipid parameters (total cholesterol, low-density lipoprotein cholesterol, triglycerides, apo B) and body fat content (P < .05) in comparison with CO group. On the other hand, RSG group rather than CO group considerably increased apo A-I levels and body mass index (P < .05). Notably, the combined treatment group yielded pronounced beneficial changes in glycemic indexes, lipid profile, insulin resistance, blood pressure, IL-10, IL-18, apo A-I, and apo B (vs CO group, P < .05). Furthermore, the addition of exercise to rosiglitazone treatment counteracted the drug-related negative effects on body weight, low-density lipoprotein, and total cholesterol. Rosiglitazone plus exercise training elicited additive effects on body composition, glycemic control, and traditional and novel cardiovascular risk factors in type 2 diabetes mellitus patients, indicating complementary effects.     

Effects of antidiabetic treatment with metformin and insulin on serum and adipose tissue adiponectin levels in db/db mice

Decreased circulating levels of adiponectin, a novel adipose-derived adipocytokine, in obesity possibly contribute to the development of insulin resistance which is a major factor in the pathogenesis of type 2 diabetes. The present study was conducted to examine whether circulating and adipose tissue adiponectin levels are modulated by chronic treatment with metformin and intensive treatment with insulin in murine models of obesity and type 2 diabetes, db/db mice with a C57BL/KsJ genetic background. Nine-week-old male db/db mice were treated with metformin, insulin, and vehicle for 4 weeks. Expectedly, metformin treatment led to inhibition of weight gain and improvement of hyperinsulinemia. Insulin treatment lowered fasting blood glucose levels to normal values, although it sustained hyperinsulinemic state. However, after 4 weeks of treatment, serum adiponectin levels were not significantly elevated in either metformin-treated or insulin-treated db/db mouse group (14.2 +/- 0.7 and 16.7 +/- 1.0 microg/ml, respectively) compared to vehicle-treated group (14.9 +/- 0.6 microg/ml). Similarly, adipose tissue adiponectin levels determined by Western blot analysis were not increased in either metformin-treated or insulin-treated group relative to vehicle-treated group. Recent studies have shown that adiponectin possibly has the same physiological effects on lipid and glucose metabolism that metformin has. Therefore, an elevation in blood concentration of metformin following the treatment might lead to suppression in adiponectin synthesis in adipose tissue, independent of inhibition in weight gain and improvement in hyperinsulinemia by metformin treatment. The present results indicate that adiponectin is not involved in the mechanism by which metformin treatment enhances insulin sensitivity. Moreover, our results suggest that adiponectin synthesis in adipose tissue may be suppressed under hyperinsulinemic state sustained by insulin treatment, even though hyperglycemia is markedly reduced. We conclude that antidiabetic treatment with metformin and insulin does not affect circulating and adipose tissue adiponectin levels.     

Effects of rosiglitazone on body fat distribution and insulin sensitivity in Korean type 2 diabetes mellitus patients

The objective of the study was to investigate the effects of rosiglitazone (RSG), a thiazolidinedione derivative, on body fat distribution and insulin sensitivity in Korean subjects with type 2 diabetes mellitus. This study was a phase IV, multicenter, single-blind, positive-controlled parallel group study. Eighty-nine patients with type 2 diabetes mellitus, aged 30 to 75 years, were enrolled in this study. Their fasting plasma glucose levels ranged from 126 to 270 mg/dL, and subjects had hemoglobin A1c levels of greater than 7.0%. We compared the effect of the treatment with glibenclamide plus RSG 4 mg/d (increased to 8 mg/d after 6 months) with glibenclamide plus placebo on body fat distributions, which were determined by computed tomography scanning and glycemic and insulinemic responses to oral glucose load. During the 12-month treatment period, the difference between the changes in the ratio of the intraabdominal adipose tissue (IAAT) to abdominal subcutaneous adipose tissue areas (SAT) between treatment groups was significant (from 1.13 +/- 0.53 to 1.00 +/- 0.40 in the RSG group and from 0.92 +/- 0.54 to 0.96 +/- 0.62 in the placebo group, P = .0351). The glycemic responses to oral glucose load (area under the curve, millimoles per liter per hour) were improved in the RSG group with 12 months of treatment (from 4.88 +/- 1.10 to 4.38 +/- 1.35 in 1 hour and from 13.78 +/- 2.83 to 12.16 +/- 2.52 in 2 hours), and the difference between the changes of the glycemic response showed statistical significance between groups (RSG group vs placebo group: -0.53 +/- 1.42 vs 0.38 +/- 1.31, difference in 1 hour; -0.76 +/- 2.98 vs 1.43 +/- 2.58, difference in 2 hours). However, there was no difference between insulin responses from baseline to follow-up and no differences in the change in insulin response between groups. In Korean subjects with type 2 diabetes mellitus, 12 months of treatment with RSG may increase SAT, but may have a neutral effect on IAAT, resulting in a decrease in the IAAT:SAT ratio. The RSG treatment improved the glucose control in type 2 diabetes mellitus. However, it is important to determine whether the glucose-lowering effect of RSG occurs mainly through direct enhancement of insulin sensitivity.