Pioglitazone administration decreases cardiovascular disease risk factors in insulin-resistant smokers

The effectiveness comparisons of eugenosedin-A, glibenclamide and pioglitazone on diabetes mellitus induced by STZ/NA and high-fat diet in SHR

OBJECTIVES

Eugenosedin-A (Eu-A), an adrenergic and serotonergic antagonist, is known to have anti-metabolic syndrome effects. In this study, we evaluated its protective effects against diabetes mellitus (DM) in spontaneous hypertensive rats (SHR) and compared it with two anti-diabetes medications, glibenclamide (Gli) and pioglitazone (Pio).

METHODS

We divided 10-week-old SHRs into five groups: a control group fed a normal diet; an untreated DM group induced by injecting the SHRs with STZ/NA and feeding them a high-fat diet (HFD); and three treated groups (after giving STZ/NA and HFD) gavage given with Eu-A, Gli or Pio (5 mg/kg per day) for 4 weeks.

KEY FINDINGS

The untreated DM group weighed less and had hyperglycaemia, hypoinsulinemia and hyperlipidemia. They were also found to have aberrant glucose-dependent insulin pathways, glucose metabolism and lipid synthesis proteins, while the controls did not. Eu-A, Gli and Pio ameliorated the above biochemical parameters in the treatment groups. Eu-A and Pio, but not Gli, improved hypertension and tachycardia.

CONCLUSIONS

Taken together, Eu-A ameliorated DM, hypertension and tachycardia by improving glucose, lipid homeostasis and anti-adrenergic, serotonergic activities. We concluded that Eu-A could be used in the development of an effective agent for controlling DM and its complications.

Circulating microRNA-320a and microRNA-486 predict thiazolidinedione response: Moving towards precision health for diabetes prevention

INTRODUCTION

The aims of this study were to compare microRNA (miR) expression between individuals with and without insulin resistance and to determine whether miRs predict response to thiazolidinedione treatment.

MATERIALS AND METHODS

In a sample of 93 healthy adults, insulin resistance was defined as steady state plasma glucose (SSPG)≥180 mg/dL and insulin sensitive as <120 mg/dL. Response to thiazolidinedione therapy was defined as ≥10% decrease in SSPG. We selected a panel of microRNAs based on prior evidence for a role in insulin or glucose metabolism. Fold change and Wilcoxon rank sum tests were calculated for the 25 miRs measured.

RESULTS

At baseline, 81% (n=75) of participants were insulin resistant. Five miRs were differentially expressed between the insulin resistant and sensitive groups: miR-193b (1.45 fold change (FC)), miR-22-3p (1.15 FC), miR-320a (1.36 FC), miR-375 (0.59 FC), and miR-486 (1.21 FC) (all p<0.05). In the subset who were insulin resistant at baseline and received thiazolidinediones (n=47), 77% (n=36) showed improved insulin sensitivity. Six miRs were differentially expressed between responders compared to non-responders: miR-20b-5p (1.20 FC), miR-21-5p, (0.92 FC), miR-214-3p (1.13 FC), miR-22-3p (1.14 FC), miR-320a (0.98 FC), and miR-486-5p (1.25 FC) (all p<0.05).

DISCUSSION

This study is the first to report miRs associated with response to a pharmacologic intervention for insulin resistance. MiR-320a and miR-486-5p identified responders to thiazolidinedione therapy among the insulin resistant group.

Correlated analysis and pathological study on insulin resistance and cardiovascular endocrine hormone in elderly hypertension patients

AIMS

The correlated analysis and pathological study on insulin resistance and cardiovascular endocrine hormone in elderly hypertension patients was investigated by clinical observation and physical experiments in my hospital.

MATERIALS AND METHODS

Randomly enrolled 300 subjects seen at hospital from January 2011 to January 2013, which included 150 hypertension patients and 150 non-hypertension of healthy people, while 150 cases of hypertension patients as the experimental group, 150 cases of healthy people without hypertension acts as the control group. The t-PA of serum (plasma), activity of PAI, ANP, IS, ET were determined in this 300 subjects, and it studied on the correlation and pathological effect between insulin resistance and cardiovascular endocrine hormone in elderly hypertension patients.

RESULTS

The levels of PAI, ANP, ET are apparently higher in hypertension patients than in healthy control group (p<0.05), while the t-PA, IS are obviously lower in hypertensive patients than in healthy control group (p>0.05).

CONCLUSION

This study has shown that there is a significant correlation and pathological effect between insulin resistance and cardiovascular endocrine hormone in hypertensive patients, and which plays an important role in genesis and development of hypertension in elderly people.

Fat redistribution preferentially reflects the anti-inflammatory benefits of pioglitazone treatment

Thiazoledinedione is known to have an anti-inflammatory effect besides a hypoglycemic effect. We investigated changes in high-sensitivity C-reactive protein (hsCRP), a proinflammatory marker, after pioglitazone treatment in association with the resulting changes in various metabolic and anthropometric parameters. A total of 93 type 2 diabetes mellitus patients (47 men and 46 women; mean age, 50.0 ± 10.8 years) who were being treated with a stable dose of sulfonylurea or metformin were enrolled in the study. Pioglitazone (15 mg/d) was added to their treatment regimen for 12 weeks, and metabolic and anthropometric measurements were taken before and after pioglitazone treatment. Pioglitazone treatment for 12 weeks decreased serum hsCRP levels (0.83 [1.14] to 0.52 [0.82] mg/L, P < .001) and improved glycemic control (fasting glucose, P < .001; glycosylated hemoglobin, P < .001) and lipid profiles (triglyceride, P = .016; high-density lipoprotein cholesterol, P < .001). Between responders and nonresponders to the hsCRP-lowering effect of pioglitazone, there were significant differences in baseline hsCRP levels and changes in the postprandial glucose and the ratio of visceral fat thickness (VFT) to subcutaneous fat thickness (SFT) (P = .004, .011, and .001, respectively). The percentage change in hsCRP levels after treatment was inversely correlated with baseline hsCRP levels (r = -0.497, P < .001) and directly correlated with the change in postprandial glucose (r = 0.251, P = .021), VFT (r = 0.246, P = .030), and VFT/SFT ratio (r = 0.276, P = .015). Logistic regression analysis revealed that the hsCRP-lowering effect of pioglitazone was affected by baseline hsCRP levels (odds ratio [OR] = 7.929, P = .007) as well as changes in postprandial 2-hour glucose (OR = 0.716, P = .025) and VFT/SFT ratio (OR = 0.055, P = .009). In conclusion, treatment with pioglitazone produced an anti-inflammatory effect, decreasing serum hsCRP levels; and a decrease in the VFT/SFT ratio was independently and most strongly associated with the hsCRP-decreasing effect. These results suggest that abdominal fat redistribution preferentially reflects the anti-inflammatory benefits of pioglitazone treatment.

Relationship between insulin resistance and C-reactive protein in a patient population treated with second generation antipsychotic medications

C-reactive protein (CRP) is an inflammatory marker associated with obesity, insulin resistance, and cardiovascular disease. A recent study found CRP levels to be higher in individuals treated with certain antipsychotic medications such as olanzapine; however, it is not clear whether this is associated directly with drug intake or indirectly with drug-associated weight gain and insulin resistance. The objective of this study was to explore the potential predictors of CRP including insulin resistance, components of the metabolic syndrome, psychiatric diagnosis, and antipsychotic medication in patients treated with antipsychotics. Sixty-four outpatients without diabetes being treated with a single second generation antipsychotic medication had direct measurements of insulin resistance at the end of a 180-min infusion of glucose, insulin, and octreotide (insulin suppression test) as well as components of the metabolic syndrome. Insulin resistance was the strongest predictor of CRP (r=0.52, P<0.001). When adjusted for insulin resistance, there was no significant relationship between CRP and any of the components of the metabolic syndrome criteria, specific drug treatment or psychiatric diagnoses. In conclusion, insulin resistance is strongly associated with CRP levels and likely contributes to earlier associations between CRP and certain antipsychotic treatments.

The impacts of thiazolidinediones on circulating C-reactive protein levels in different diseases: a meta-analysis

OBJECTIVES

Thiazolidinediones (TZDs), including rosiglitazone and pioglitazone, are widely used as antidiabetic agents. Here we present an updated meta-analysis of the respective effects of rosiglitazone and pioglitazone on the levels of C-reactive protein (CRP), a biomarker and predictor of CAD risks.

METHODS AND RESULTS

PubMed and EMBASE were systematically searched using the terms "C-reactive protein" and "rosiglitazone" or "pioglitazone" or "thiazolidinedione". A total of 59 rosiglitazone studies and 36 pioglitazone studies were included for evaluation. These were classified as 2-group studies and 1-group studies according to their study design. Standard mean difference (SMD) of CRP and 95% CI were calculated to evaluate the effect of TZDs on CRP. The overall SMD for rosiglitazone treatment is -0.392 (95% CI, [-0.446, -0.338]) in 2-group studies and -0.424 (95% CI, [-0.501, -0.346]) in 1-group studies. The overall SMD for pioglitazone treatment is -0.577 (95% CI, [-0.732, -0.421]) in 2-group studies and -0.327 (95% CI, [-0.439, -0.216]) in 1-group studies. Moreover, TZDs were found to significantly reduce CRP levels in both diabetes mellitus (DM) and non-DM patients.

CONCLUSIONS

Our meta-analysis suggested that both rosiglitazone and pioglitazone significantly decrease serum CRP levels. TZDs presented their CRP-lowering effect in both DM and non-DM patients.

Intramuscular lipid metabolism in the insulin resistance of smoking

OBJECTIVE

Smoking decreases insulin action and increases the risk of type 2 diabetes in humans. Mechanisms responsible for smoking-induced insulin resistance are unclear. We hypothesized smokers would have increased intramuscular triglyceride (IMTG) and diacylglycerol (DAG) concentration and decreased fractional synthesis rate (FSR) compared with nonsmokers.

RESEARCH DESIGN AND METHODS

Nonsmokers (n = 18, aged 20 +/- 0.5 years, BMI 22 +/- 0.4 kg/m(2), body fat 20 +/- 2%, 0 cigarettes per day) and smokers (n = 14, aged 21 +/- 0.7 years, BMI 23 +/- 0.4 kg/m(2), body fat 20 +/- 3%, 18 +/- 0.7 cigarettes per day) were studied in a fasted condition after a standardized diet. [U-(13)C]palmitate was infused during 4 h of rest followed by a skeletal muscle biopsy and intravenous glucose tolerance test.

RESULTS

Smokers were less insulin sensitive (S(i)) compared with nonsmokers (S(i) 5.28 +/- 0.5 nonsmokers vs. 3.74 +/- 0.3 smokers 10(-4) x microU(-1) x ml(-1), P = 0.03). There were no differences in IMTG or DAG concentration (IMTG 24.2 +/- 3.4 nonsmokers vs. 27.2 +/- 5.9 smokers microg/mg dry wt, DAG 0.34 +/- 0.02 nonsmokers vs. 0.35 +/- 0.02 smokers microg/mg dry wt) or IMTG FSR between groups (0.66 +/- 0.1 nonsmokers vs. 0.55 +/- 0.09 smokers %/hr). Intramuscular lipid composition was different, with increased percent saturation of IMTG (32.1 +/- 1.2 nonsmokers vs. 35.2 +/- 1.0 smokers %, P = 0.05) and DAG (52.8 +/- 1.7 nonsmokers vs. 58.8 +/- 2.2 smokers %, P = 0.04) in smokers. Smokers had significantly decreased peroxisome proliferator-activated receptor-gamma (1.76 +/- 0.1 nonsmokers vs. 1.42 +/- 0.11 smokers arbitrary units [AU], P = 0.03) and increased monocyte chemotactic protein-1 (3.11 +/- 0.41 nonsmokers vs. 4.83 +/- 0.54 smokers AU, P = 0.02) mRNA expression compared with nonsmokers. We also found increased insulin receptor substrate-1 Ser(636) phosphorylation in smokers compared with nonsmokers (0.73 +/- 0.08 nonsmokers vs. 1.14 +/- 0.09 smokers AU, P = 0.002).

CONCLUSIONS

These data suggest: 1) IMTG concentration and turnover are not related to alterations in insulin action in smokers compared to nonsmokers, 2) increased saturation of IMTG and DAG in skeletal muscle may be related to insulin action, and 3) basal inhibition of insulin receptor substrate-1 may decrease insulin action in smokers.

Pioglitazone decreases postprandial accumulation of remnant lipoproteins in insulin-resistant smokers

BACKGROUND

Fasting hypertriglyceridaemia has been reported to occur commonly in cigarette smokers and is thought to increase cardiovascular disease (CVD) risk in these individuals. More recently, it has been suggested that an increase in non-fasting triglycerides, rather than fasting hypertriglyceridaemia, is an independent CVD risk factor.

METHODS

In this study, we divided 24 smokers into insulin-resistant (IR) and insulin-sensitive (IS) groups by determining their steady-state plasma glucose concentrations during the insulin suppression test and compared fasting and daylong postprandial accumulation of total triglycerides and remnant lipoprotein (RLP) concentrations, before and after 3 months of pioglitazone (PIO) administration.

RESULTS

The two groups were similar in age, body mass index, race and gender distribution, but differed dramatically in insulin sensitivity. Baseline fasting and postprandial triglyceride, RLP cholesterol and RLP triglyceride concentrations were significantly higher in the IR smokers (p=0.01 to <0.01). Insulin resistance [corrected] and both fasting and postprandial triglyceride and RLP triglyceride levels decreased significantly (p=0.05 to 0.01) [corrected] in PIO-treated IR smokers, without any significant increase in weight instead of insulin sensitivity and both fasting and postprandial triglyceride and RLP triglyceride levels decreased significantly (p = 0.05 to, 0.01) in PIO-treated IR smokers, without any significant increase in weight. [corrected]

CONCLUSIONS

The postprandial accumulation of RLP particles is increased in the IR subset of smokers and is likely to contribute to the increased CVD risk in these individuals. Furthermore, PIO administration provides a possible therapeutic approach to decreasing postprandial lipaemia and CVD risk in IR smokers who are unwilling or unable to stop smoking.