Effect of insulin sensitizer therapy on atherothrombotic and inflammatory profiles associated with insulin resistance

Target/therapies for chronic recurrent erythema nodosum leprosum

A Type 2 lepra reaction or erythema nodosum leprosum is an anticipated complication in the lepromatous spectrum of leprosy cases. It is an example of an immune complex-mediated complement activated disease (Type III hypersensitivity reaction). Hence, we tried to target the inflammatory mediators and the mental stressors for the possible management strategies.

Two-hour postload plasma glucose and pigment epithelium-derived factor levels are markers of coronary artery inflammation in type 2 diabetic patients

BACKGROUND

We have previously found that pioglitazone attenuates inflammation in the left main trunk of coronary artery (LMT), evaluated as target-to-background ratio (TBR) by 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in patients with impaired glucose tolerance or type 2 diabetes.

OBJECTIVES

We assessed which clinical variables could predict the change in TBR in the LMT after 4-month add-on therapy with oral hypoglycemic agents (OHAs).

METHODS

A total of 38 type 2 diabetic patients with carotid atherosclerosis who had already received OHAs except for pioglitazone was enrolled. At baseline and 4 months after add-on therapy with pioglitazone or glimepiride, all patients underwent 75 g oral glucose tolerance test, blood chemistry analysis, and FDG-PET/CT.

RESULTS

Fasting plasma glucose, 30-, 60-, 90-, 120-minutes postload plasma glucose, HbA1c, and LMT-TBR values were significantly decreased by add-on therapy, whereas high-density lipoprotein-cholesterol and adiponectin levels were increased. Increased serum levels of pigment epithelium-derived factor (PEDF), a marker of insulin resistance and non-use of aspirin at baseline could predict the favorable response of LMT-TBR to add-on therapy. Moreover, Δ120-minutes postload plasma glucose and ΔPEDF were independent correlates of ΔLMT-TBR.

CONCLUSIONS

Our present study suggests that 120-minutes postload plasma glucose and PEDF values may be markers and potential therapeutic targets of coronary artery inflammation in type 2 diabetic patients.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov . Unique identifier: NCT00722631. New markers for diabetes and CAD is on the horizon! Two-hour postload plasma glucose and pigment epithelium derived factor are markers of coronary artery inflammation in type 2 diabetic patients.

Rationale and Study Design of a Randomized Clinical Trial of Metformin to Prevent Frailty in Older Adults With Prediabetes

BACKGROUND

Frailty is a geriatric syndrome that leads to poor health outcomes with aging. Previous studies have demonstrated that insulin resistance and inflammation predict frailty onset. Metformin is a widely used, well-tolerated drug that improves insulin sensitivity and displays anti-inflammatory properties. It is also known to prevent diabetes onset in adults with prediabetes. We hypothesize that metformin in older adults with prediabetes will promote healthy aging and prevent frailty. Here we describe an ongoing placebo-controlled, double-blinded clinical trial of metformin for the prevention of frailty in older adults with prediabetes.

METHODS

Older adults aged more than 65 years are randomized to metformin or placebo and are followed for 2 years. Prediabetes, required for inclusion, is assessed by 2-hour oral glucose tolerance test. Exclusion criteria are baseline frailty (Fried criteria), diabetes, dementia, untreated depression, active malignancy, or severe cardiovascular, pulmonary, and neurologic diseases. Primary outcome is frailty; secondary outcomes are physical function (Short Physical Performance Battery), systemic and skeletal muscle tissue inflammation, muscle insulin signaling, insulin sensitivity (insulin clamp), glucose tolerance (oral glucose tolerance test), and body composition (dual-energy x-ray absorptiometry). Subjects are followed every 3 months for safety assessments and every 6 months for frailty assessment (Fried criteria) and oral glucose tolerance test, and every 12 or 24 months for secondary outcomes. Enrollment of 120 subjects (completers) will take place over a 2-year period.

CONCLUSION

Metformin is being examined in this study as a potential therapeutic agent to prevent frailty in older adults with prediabetes. Findings from this trial may have future implications for the screening and potential treatment of prediabetes in older patients with metformin for the prevention of frailty.

Senescence marker activin A is increased in human diabetic kidney disease: association with kidney function and potential implications for therapy

OBJECTIVE

Activin A, an inflammatory mediator implicated in cellular senescence-induced adipose tissue dysfunction and profibrotic kidney injury, may become a new target for the treatment of diabetic kidney disease (DKD) and chronic kidney diseases. We tested the hypothesis that human DKD-related injury leads to upregulation of activin A in blood and urine and in a human kidney cell model. We further hypothesized that circulating activin A parallels kidney injury markers in DKD.

RESEARCH DESIGN AND METHODS

In two adult diabetes cohorts and controls (Minnesota, USA; Galway, Ireland), the relationships between plasma (or urine) activin A, estimated glomerular filtration rate (eGFR) and DKD injury biomarkers were tested with logistic regression and correlation coefficients. Activin A, inflammatory, epithelial-mesenchymal-transition (EMT) and senescence markers were assayed in human kidney (HK-2) cells incubated in high glucose plus transforming growth factor-β1 or albumin.

RESULTS

Plasma activin A levels were elevated in diabetes (n=206) compared with controls (n=76; 418.1 vs 259.3 pg/mL; p<0.001) and correlated inversely with eGFR (r_s=-0.61; p<0.001; diabetes). After eGFR adjustment, only albuminuria (OR 1.56, 95% CI 1.16 to 2.09) and tumor necrosis factor receptor-1 (OR 6.40, 95% CI 1.08 to 38.00) associated with the highest activin tertile. Albuminuria also related to urinary activin (r_s=0.65; p<0.001). Following in vitro HK-2 injury, activin, inflammatory, EMT genes and supernatant activin levels were increased.

CONCLUSIONS

Circulating activin A is increased in human DKD and correlates with reduced kidney function and kidney injury markers. DKD-injured human renal tubule cells develop a profibrotic and inflammatory phenotype with activin A upregulation. These findings underscore the role of inflammation and provide a basis for further exploration of activin A as a diagnostic marker and therapeutic target in DKD.

Effect of metformin combined with lifestyle modification versus lifestyle modification alone on proinflammatory-oxidative status in drug-naïve pre-diabetic and diabetic patients: A randomized controlled study

BACKGROUND

Targeting biomarkers of oxidative-proinflammatory stress may result in improvement of modifiable metabolic syndrome, pre-diabetes and diabetes risk factors and subsequent risk reduction.

METHODS

64 newly diagnosed antihyperglycemic treatment-naïve prediabetic and type 2 diabetes mellitus (T2DM) patients were randomly assigned using block design to either metformin combined with therapeutic lifestyle changes (TLC) or TLC alone. Body mass index (BMI), waist circumference, blood pressure, fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), fasting lipid profile, plasma oxidative status and tumor necrosis factor (TNF)-α were measured at baseline, after 3 months and after 6 months from baseline.

RESULTS

Except for HbA1c, baseline values did not differ significantly between the two groups. The post 3-months relative reductions in BMI (P=0.014) and HbA1c (P=0.037) in metformin combined with TLC intervention were significantly greater than those in TLC alone group. TNFα plasma levels were decreased significantly vs. baseline by metformin combined with TLC intervention (-22.90±46.76%, P=0.01). Conversely, TLC alone basically worsened proinflammatory status (42.40±40.82 %), P<0.001. Metformin with TLC treatment effected a therapeutic decrement of the oxidative stress (-15.44±35.32%, P=0.029 vs. baseline) unlike TLC alone (61.49±122.66%, P=0.01 vs. baseline). Both interventions' effects were sustained in the 6-month follow up periods.

CONCLUSION

In both intervention groups, the relative changes in plasma TNFα were significantly correlated (P<0.01) with systolic blood pressure and the relative changes in oxidative stress were markedly correlated (P<0.05) with total cholesterol.

Effect of insulin sensitizer therapy on amino acids and their metabolites

AIMS

Prior studies have reported that elevated concentrations of several plasma amino acids (AA), particularly branched chain (BCAA) and aromatic AA predict the onset of type 2 diabetes. We sought to test the hypothesis that circulating BCAA, aromatic AA and related AA metabolites decline in response to the use of insulin sensitizing agents in overweight/obese adults with impaired fasting glucose or untreated diabetes.

METHODS

We performed a secondary analysis of a randomized, double-blind, placebo, controlled study conducted in twenty five overweight/obese (BMI ~30kg/m(2)) adults with impaired fasting glucose or untreated diabetes. Participants were randomized to three months of pioglitazone (45mg per day) plus metformin (1000mg twice per day, N=12 participants) or placebo (N=13). We measured insulin sensitivity by the euglycemic-hyperinsulinemic clamp and fasting concentrations of AA and AA metabolites using ultra-pressure liquid chromatography tandem mass spectrometry before and after the three-month intervention.

RESULTS

Insulin sensitizer therapy that significantly enhanced insulin sensitivity reduced 9 out of 33 AA and AA metabolites measured compared to placebo treatment. Moreover, insulin sensitizer therapy significantly reduced three functionally clustered AA and metabolite pairs: i) phenylalanine/tyrosine, ii) citrulline/arginine, and iii) lysine/α-aminoadipic acid.

CONCLUSIONS

Reductions in plasma concentrations of several AA and AA metabolites in response to three months of insulin sensitizer therapy support the concept that reduced insulin sensitivity alters AA and AA metabolites.

The effect of pioglitazone on circulating interleukin-10 and tumor necrosis factor-alpha levels in a patient with metabolic syndrome: A randomized, double-blind controlled trial

BACKGROUND

This study aimed to evaluate the effect of pioglitazone as an insulin sensitizer on circulating interleukin-10 (IL-10) as an anti-inflammatory factor and tumor necrosis factor-alpha (TNF-α) as main proinflammatory factor in non-diabetic metabolic syndrome (MetS) patients in Caucasians race of Middle East area in Iran.

METHODS

We conducted a randomized double-blind controlled study of 68 non-diabetic patients with MetS. Patients were randomly divided into two groups including intervention group received pioglitazone 30 mg daily for 24 weeks, and the control group received placebo pills for the same duration. Circulating levels of TNF-α and IL-10 were assessed as a primary goal. Lipid profile, liver enzymes, blood pressure (BP), waist circumference, and body mass index (BMI) also were measured.

RESULTS

Lipid profile and fasting blood sugar had non-significant changes after treatment by pioglitazone, but BMI was increased significantly (P = 0.002). BP and waist circumference had a significant decrease in both groups (P < 0.050). Aspartate transaminase and alanine transaminase were decreased significantly in the pioglitazone group (P = 0.002). TNF-α decreased non-significantly in both groups (P > 0.050). IL-10 increased in intervention group non-significantly (P = 0.971); whereas in placebo group decreased to a little extent (P = 0.401). C-reactive protein was also decreased insignificant after receive pioglitazone (P = 0.333). There was no significant difference in all variables between the two groups (P > 0.050) except liver enzymes (P < 0.050).

CONCLUSION

This study indicates that the pioglitazone has no positive effect on improving inflammatory status in the non-diabetes patients with MetS.

METABOLIC EFFECTS OF ADIPONECTINE

The metabolic effects of adiponectine are discussed and its possible role in the development of metabolic syndrome, insulin resistance, diabetes mellitus 2nd type, atherosclerosis; prognostic significance of adiponectine as a marker for ischemic heart disease and future cardiovascular events, therapeutical perspectives of adiponectine use. 

Peroxisome proliferator-activated receptor γ agonist effect on rheumatoid arthritis: a randomized controlled trial

Introduction

Rheumatoid arthritis (RA), a chronic inflammatory disease, is associated with insulin resistance. Experimental evidence indicates that the relationship between insulin resistance and inflammation is bidirectional: Inflammation promotes insulin resistance, and insulin resistance promotes inflammation. Therefore, we examined the hypothesis that pioglitazone, a thiazolidinedione peroxisome proliferator-activated receptor γ agonist, would decrease inflammation and disease activity and improve insulin resistance in patients with RA.

Methods

In a single-center, randomized, double-blind, placebo-controlled crossover study patients with RA (N = 34) receiving stable therapy were randomized to also receive either pioglitazone 45 mg daily (n = 17) or matching placebo (n = 17) for eight weeks. This was followed by a four-week washout period and alternative treatment for eight weeks. Outcomes included change in Disease Activity Score in 28 joints (DAS28) score, individual components of the DAS28 score and homeostatic model assessment for insulin resistance (HOMA). Intention-to-treat analysis and linear mixed-effects models were used.

Results

Patients had a mean (±SD) age of 51 (±14.2) years, 82.4% were female and baseline DAS28 high-sensitivity C-reactive protein (DAS28-CRP) was 4.58 (±1.1) units. Addition of pioglitazone was associated with a 9.3% reduction (95% confidence interval (CI) = 0.17% to 17.6%) in DAS28-CRP (P = 0.046), but no significant change in DAS28 erythrocyte sedimentation rate (DAS28-ESR) (P = 0.92). There was a 10.7mm (95% CI = 0.4 to 20.9 mm) improvement in patient-reported global health (P = 0.042), a 48.6% decrease (95% CI = 27.6% to 63.5%) in CRP (P < 0.001) and a 26.4% decrease (95% CI = 3.7% to 43.8%) in insulin resistance as measured by HOMA (P = 0.025), but no significant reduction in swollen or tender joint count or in ESR (all P > 0.05). Lower-extremity edema was more common during pioglitazone treatment (16%) than placebo (0%).

Conclusion

Addition of pioglitazone to RA therapy improves insulin resistance and modestly reduces RA disease activity measured by DAS28-CRP and two of its components, including patient-reported global health and CRP, but not DAS28-ESR or ESR.

Trial registration

NCT00763139

Reduced adipose tissue macrophage content is associated with improved insulin sensitivity in thiazolidinedione-treated diabetic humans

Obesity is associated with increased adipose tissue macrophage (ATM) infiltration, and rodent studies suggest that inflammatory factors produced by ATMs contribute to insulin resistance and type 2 diabetes. However, a relationship between ATM content and insulin resistance has not been clearly established in humans. Since thiazolidinediones attenuate adipose tissue inflammation and improve insulin sensitivity, we examined the temporal relationship of the effects of pioglitazone on these two parameters. The effect of 10 and 21 days of pioglitazone treatment on insulin sensitivity in 26 diabetic subjects was assessed by hyperinsulinemic-euglycemic clamp studies. Because chemoattractant factors, cytokines, and immune cells have been implicated in regulating the recruitment of ATMs, we studied their temporal relationship to changes in ATM content. Improved hepatic and peripheral insulin sensitivity was seen after 21 days of pioglitazone. We found early reductions in macrophage chemoattractant factors after only 10 days of pioglitazone, followed by a 69% reduction in ATM content at 21 days and reduced ATM activation at both time points. Although markers for dendritic cells and neutrophils were reduced at both time points, there were no significant changes in regulatory T cells. These results are consistent with an association between adipose macrophage content and systemic insulin resistance in humans.

Weight loss by multidisciplinary intervention improves endothelial and sexual function in obese fertile women

INTRODUCTION

Weight loss in sexually active women improves their quality of life. At present, no studies have investigated whether weight loss may affect female sexual function in severe obese women.

AIM

The aim of this study was to investigate the effects of different programs of weight loss on female sexual dysfunction complaints and on endothelial function in premenopausal obese females.

METHODS

Forty-four out of overall 80 obese fertile women (age 18-49 years; mean 36 years) were enrolled because of sexual complaints at Female Sexual Function Index-6 (FSFI-6 score ≤19). Patients were then allocated to different treatments of 8 weeks duration each: an intensive residential program with hypocaloric diet plus controlled physical exercise along with lifestyle modifications at a specialized clinic (Group A, N = 23) and a non-intensive outpatient clinic program consisting of hypocaloric diet and physical exercise at home (Group B, N = 21). Afterward, overall patients were allocated to an extended 8-week follow-up period consisting of outpatient clinic controlled diet plus physical exercise at home.

MAIN OUTCOME MEASURES

Primary end points were modifications of FSFI-6 scores and endothelial function as measured by reactive hyperemia (RHI) with EndoPat-2000. Secondary end points were modifications in body composition as measured by dual-energy X-ray absorptiometry (DEXA).

RESULTS

After 16 weeks, FSFI-6 score and the frequency of sexual activity were significantly higher in Group A compared with Group B (P < 0.01), and significant improvements in arousal, lubrication, and satisfaction sub-domain scores were also found (P < 0.01). Group A showed improvements in RHI (P < 0.01) and marked improvement in homeostasis model assessment of insulin resistance (P < 0.001), anthropometric parameters as weight (P < 0.01), body mass index (P < 0.01), fat mass (P < 0.0001), and percentage of fat mass (P < 0.005) compared with Group B. A relationship between peak insulin (P < 0.0001) and RHI (P < 0.001) vs. FSFI-6 scores was found, respectively.

CONCLUSIONS

A multidisciplinary approach to female obesity appears to be superior to conventional outpatient clinic to produce weight loss and to improve several aspects of sexual dysfunction in obese women. Such changes might be related to persistent improvements in endothelial function and in insulin resistance.