PPARγ agonist rosiglitazone ameliorates LPS-induced inflammation in vascular smooth muscle cells via the TLR4/TRIF/IRF3/IP-10 signaling pathway

The activation of toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) can induce inflammation that are one of key etiological conditions for the development of many chronic inflammatory diseases including atherosclerosis and diabetes. Peroxisome proliferator-activated receptor γ (PPARγ) agonists play a crucial role in improving glucose and lipid homeostasis in the development of cardiovascular diseases. Evidence is growing that benefits of PPARγ agonists may also be derived from the anti-inflammatory and anti-atherosclerotic properties of these agents. However, the role of rosiglitazone in regulating LPS-induced vascular inflammation has yet to be fully elucidated. The current study demonstrated that rosiglitazone exerted a potent anti-inflammatory action via decreasing interleukin-18 (IL-18), tissue inhibitor of metalloproteinase-1 (TIMP-1), TLR4 and increasing PPARγ in LPS-induced VSMCs. Furthermore, treatment of VSMCs with the TLR4 blocker or TLR4 small-interfering RNA presented that the regulatory effects of rosiglitazone on LPS-mediated inflammation in VSMCs were dependent on TLR4. Interestingly, the results indicated that beneficial effects of rosiglitazone on LPS-induced inflammation in VSMCs were mediated via interference of TLR4 and its downstream signaling components including Toll-interleukin-1 (IL-1) receptor domain-containing adaptor inducing interferon-β (TRIF), interferon regulatory factor 3 (IRF3) and interferon-gamma inducible protein 10 (IP-10). In summary, PPARγ agonist rosiglitazone exerts anti-inflammatory property by antagonizing LPS-mediated inflammation in VSMCs. More importantly, the regulation of the TRIF-dependent TLR4 signaling pathway (TLR4/TRIF/ IRF3/IP-10) provides new insight to understand the mode of action of rosiglitazone for its anti-inflammatory effects.     

Exercise reverses high-fat diet-induced impairments on compartmentalization and activation of components of the insulin-signaling cascade in skeletal muscle

The aims of this investigation were 1) to determine whether endurance exercise training could reverse impairments in insulin-stimulated compartmentalization and/or activation of aPKCzeta/lambda and Akt2 in skeletal muscle from high-fat-fed rodents and 2) to assess whether the PPARgamma agonist rosiglitazone could reverse impairments in skeletal muscle insulin signaling typically observed after high-fat feeding. Sprague-Dawley rats were placed on chow (NORCON, n = 16) or high-fat (n = 64) diets for 4 wk. During a subsequent 4-wk experimental period, high-fat-fed rats were allocated (n = 16/group) to either sedentary control (HFC), exercise training (HFX), rosiglitazone treatment (HFRSG), or a combination of both exercise training and rosiglitazone (HFRX). Following the 4-wk experimental period, animals underwent hindlimb perfusions. Insulin-stimulated plasma membrane-associated aPKCzeta and -lambda protein concentration, aPKCzeta/lambda activity, GLUT4 protein concentration, cytosolic Akt2, and aPKCzeta/lambda activities were reduced (P < 0.05) in HFC compared with NORCON. Cytosolic Akt2, aPKCzeta, and aPKClambda protein concentrations were not affected in HFC compared with NORCON. Exercise training reversed the deleterious effects of the high-fat diet such that insulin-stimulated compartmentalization and activation of components of the insulin-signaling cascade in HFX were normalized to NORCON. High-fat diet-induced impairments to skeletal muscle glucose metabolism were not reversed by rosiglitazone administration, nor did rosiglitazone augment the effect of exercise. Our findings indicate that chronic exercise training, but not rosiglitazone, reverses high-fat diet induced impairments in compartmentalization and activation of components of the insulin-signaling cascade in skeletal muscle.     

Subcutaneous Abdominal Adipose Tissue Subcompartments: Potential Role in Rosiglitazone Effects

Abdominal visceral tissue (VAT) and subcutaneous adipose tissue (SAT), comprised of superficial‐SAT (sSAT) and deep‐SAT (dSAT), are metabolically distinct. The antidiabetic agents thiazolidinediones (TZDs), in addition to their insulin‐sensitizing effects, redistribute SAT suggesting that TZD action involves adipose tissue depot‐specific regulation. We investigated the expression of proteins key to adipocyte metabolism on differentiated first passage (P1) preadipocytes treated with rosiglitazone, to establish a role for the diverse depots of abdominal adipose tissue in the insulin‐sensitizing effects of TZDs. Adipocytes and preadipocytes were isolated from sSAT, dSAT, and VAT samples obtained from eight normal subjects. Preadipocytes (P1) left untreated (U) or treated with a classic differentiation cocktail (DI) including rosiglitazone (DIR) for 9 days were evaluated for strata‐specific differences in differentiation including peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) and lipoprotein lipase (LPL) expression, insulin sensitivity via adiponectin and glucose transport‐4 (GLUT4), glucocorticoid metabolism with 11β‐hydroxysteroid dehydrogenase type‐1 (11βHSD1), and alterations in the adipokine leptin. While depot‐specific differences were absent with the classic differentiation cocktail, with rosiglitazone sSAT had the most potent response followed by dSAT, whereas VAT was resistant to differentiation. With rosiglitazone, universal strata effects were observed for PPAR‐γ, LPL, and leptin, with VAT in all cases expressing significantly lower basal expression levels. Clear dSAT‐specific changes were observed with decreased intracellular GLUT4. Specific sSAT alterations included decreased 11βHSD1 whereas secreted adiponectin was potently upregulated in sSAT with respect to dSAT and VAT. Overall, the subcompartments of SAT, sSAT, and dSAT, appear to participate in the metabolic changes that arise with rosiglitazone administration.     

Anti-proliferative effect of rosiglitazone on angiotensin II-induced vascular smooth muscle cell proliferation is mediated by the mTOR pathway

VSMC (vascular smooth muscle cell) proliferation contributes significantly to intimal thickening in atherosclerosis, restenosis and venous bypass graft diseases. Ang II (angiotensin II) has been implicated in VSMC proliferation though the activation of multiple growth-promoting signals. Although TZDs (thiazolidinediones) can inhibit VSMC proliferation and reduce Ang II-induced fibrosis, the mechanism underlying the inhibition of VSMC proliferation and fibrosis needs elucidation. We have used primary cultured rat aortic VSMCs and specific antibodies to investigate the inhibitory mechanism of rosiglitazone on Ang II-induced VSMC proliferation. Rosiglitazone treatment significantly inhibited Ang II-induced rat aortic VSMC proliferation in a dose-dependent manner. Western blot analysis showed that rosiglitazone significantly lowered phosphorylated ERK1/2 (extracellular-signal-regulated kinase 1/2), Akt (also known as protein kinase B), mTOR (mammalian target of rapamycin), p70S6K (70 kDa S6 kinase) and 4EBP1 (eukaryotic initiation factor 4E-binding protein) levels in Ang II-treated VSMCs. In addition, PPAR-γ (peroxisome-proliferator-activated receptor γ) mRNA increased significantly and CTGF (connective tissue growth factor), Fn (fibronectin) and Col III (collagen III) levels decreased significantly. The results demonstrate that the rosiglitazone directly inhibits the pro-atherosclerotic effect of Ang II on rat aortic VSMCs. It also attenuates Ang II-induced ECM (extracellular matrix) molecules and CTGF production in rat aortic VSMCs, reducing fibrosis. Importantly, PPAR-γ activation mediates these effects, in part, through the mTOR-p70S6K and -4EBP1 system.     

PPARγ-dependent pathway in the growth-inhibitory effects of K562 cells by carotenoids in combination with rosiglitazone

Background

Carotenoids have been found to play roles in the prevention and therapy of some cancers which PPARγ was also discovered to be involved in. The present studies were directed to determine the inhibitory effects of carotenoids in combination with rosiglitazone, a synthetic PPARγ agonist, on K562 cell proliferation and elucidate the contribution of PPARγ-dependent pathway to cell proliferation suppression.

Methods

The effects of carotenoid and rosiglitazone combination on K562 cell proliferation were evaluated by trypan blue dye exclusion assay and MTT assay. When PPARγ has been inhibited by GW9662 and siRNA, cycle-related regulator expression in K562 cells treated with carotenoid and rosiglitazone combination was analyzed by Western blotting.

Results

Rosiglitazone inhibited K562 cell proliferation and augmented the inhibitory effects of carotenoids on the cell proliferation greatly. Specific PPARγ inhibition attenuated the cell growth suppression induced by carotenoid and rosiglitazone combination. GW9662 pre-treatment attenuated the enhanced up-regulation of PPARγ expression caused by the combination treatment. Moreover, GW9662 and PPARγ siRNA also significantly attenuated the up-regulation of p21 and down-regulation of cyclin D1 caused by carotenoids and rosiglitazone.

Conclusions

PPARγ signaling pathway, via stimulating p21 and inhibiting cyclin D1, may play an important role in the anti-proliferative effects of carotenoid and rosiglitazone combination on K562 cells.

General significance

Carotenoids in combination with rosiglitazone are hopeful to provide attractive dietary or supplementation-based and pharmaceutical strategies to treat cancer diseases.     

罗格列酮对海马神经元树突发育的影响

罗格列酮(rosiglitazone,Rosig.)是噻唑烷二酮类(thiazolidinediones,TZDs)过氧化物酶体增殖物激活受体γ(peroxisome proliferator-activated receptor gamma,PPARγ)的激动剂,近年来,临床研究发现其具有神经保护作用,但对其作用机制目前仍没有完全研究清楚．利用活细胞成像的方法,观察罗格列酮对大鼠海马神经元树突丝和树突树发育的影响及其机制．结果显示,罗格列酮浓度依赖的增高神经元树突丝密度,对树突丝长度、运动速度并没有影响．此外,罗格列酮也不影响树突树的总分支、总长度以及各级分支的数目和长度．PPARγ 特异性拮抗剂GW9662完全阻断了罗格列酮介导的树突丝密度增高．结果表明罗格列酮可能通过PPARγ途径影响神经元的早期发育,这可能是罗格列酮发挥神经保护作用的潜在机制．     

Risk of death and cardiovascular outcomes with thiazolidinediones: a study with the general practice research database and secondary care data

Objective

To describe the likely extent of confounding in evaluating the risks of cardiovascular (CV) events and mortality in patients using diabetes medication.

Methods

The General Practice Research Database was used to identify inception cohorts of insulin and different oral antidiabetics. An analysis of bias and incidence of mortality, acute coronary syndrome, stroke and heart failure were analysed in GPRD, Hospital Episode Statistics and death certificates.

Results

206,940 patients were identified. The bias analysis showed that past thiazolidinedione users had a lower mortality risk compared to past metformin users. There were no differences between past users of rosiglitazone and pioglitazone (adjusted RR of 1.04; 95% CI 0.93–1.18). Current rosiglitazone users had an increased risk of death (adjusted RR 1.20; 95% CI 1.08–1.34) and of hospitalisation for heart failure (adjusted RR of 1.73; 95% CI 1.19–2.51) compared to current pioglitazone users. Risk of mortality was increased two-fold shortly after starting rosiglitazone. Excess risk of death over 3 years with rosiglitazone was 0.3 per 100 in those aged 50–64 years, 2.0 aged 65–74, 3.0 aged 75–84, and 7.0 aged 85+. The cause of death with rosiglitazone was more likely to be due to a disease of the circulatory system.

Conclusions

Higher risks for death (overall and due to cardiovascular disease) and heart failure were found for rosiglitazone compared to pioglitazone. These excess risks were largest in patients aged 65 years or older. The European regulatory decision to suspend rosiglitazone is supported by this study.     

Novel (S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acids: peroxisome proliferator-activated receptor γ selective agonists with protein-tyrosine phosphatase 1B inhibition

A novel series of 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid derivatives were synthesized and (S)-2-[(2E,4E)-hexadienoyl]-7-(2-{5-methyl-2-[(1E)-5-methylhexen-1-yl]oxazol-4-yl}ethoxy)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (14i) was identified as a potent human peroxisome proliferator-activated receptor γ (PPARγ) selective agonist (EC(50)=0.03 μM) and human protein-tyrosine phosphatase 1B (PTP-1B) inhibitor (IC(50)=1.18 μM). C(max) after oral administration of 14i at 10mg/kg was 2.2 μg/ml (4.5 μM) in male SD rats. Repeated administration of 14i and rosiglitazone for 14 days dose-dependently decreased plasma glucose levels, ED(50)=4.3 and 23 mg/kg/day, respectively, in male KK-A(y) mice. In female SD rats, repeated administration of 14i at 12.5-100mg/kg/day for 28 days had no effect on the hematocrit value (Ht) and red blood cell count (RBC), while rosiglitazone significantly decreased them from 25mg/kg/day. In conclusion, 14i showed about a fivefold stronger hypoglycemic effect and fourfold or more weaker hemodilution effect than rosiglitazone, indicating that 14i is 20-fold or more safer than rosiglitazone. Compound 14i is a promising candidate for an efficacious and safe anti-diabetic drug targeting PPARγ and PTP-1B.     

Thiazolidinediones and the renal and hormonal response to water immersion-induced volume expansion in type 2 diabetes mellitus

Thiazolidinediones cause sodium retention and edema by a direct effect on the kidneys. The aim of this study was to use the technique of head-out water immersion to investigate the effects of rosiglitazone on sodium and volume homeostasis in subjects with type 2 diabetes mellitus. The volume expansion response to water immersion was compared with the response on a non-immersion control day in 12 nondiabetic male subjects and 8 diet-controlled male type 2 diabetic subjects with hourly blood and urine sampling over a 4-h period. This was repeated after both groups had taken 4 mg of rosiglitazone daily for 7 days. Immersion produced a natriuresis in both groups (P < 0.001). An impairment of this natriuresis was seen in the diabetic subjects (P = 0.006). However, when rosiglitazone was taken, there was no significant difference in immersion-induced natriuresis compared with nondiabetic controls (P = 0.2). There was an immersion-induced rise in atrial natriuretic peptide (ANP) and urinary cyclic guanosine monophosphate (cGMP), in the healthy subjects (ANP P = 0.001, cGMP P = 0.043), which was not seen in the diabetic subjects (ANP P = 0.51, cGMP P = 0.74). Rosiglitazone restored the immersion-induced increase in cGMP excretion and rise of ANP in the diabetic group (ANP P = 0.048, cGMP P = 0.009). This study confirms that type 2 diabetic subjects have an impaired natriuretic response to acute volume expansion, which appears to be enhanced rather than diminished by rosiglitazone. This may be related to its effects in increasing natriuretic peptides and restoring the impaired cGMP excretion to volume expansion.     

PPAR-gamma inhibits ANG II-induced cell growth via SHIP2 and 4E-BP1

The present study evaluated the effects of peroxisome proliferator-activated receptor (PPAR)-gamma activators on ANG II-induced signaling pathways and cell growth. Vascular smooth muscle cells (VSMC) derived from rat mesenteric arteries were treated with ANG II, with/without the AT1 receptor blocker valsartan or the AT2 receptor blocker PD-123319, after pretreatment for 24 h with the PPAR-gamma activators 15-deoxy-delta(12,14)-prostaglandin J2 (15d-PGJ2) or rosiglitazone. Both 15d-PGJ2 and rosiglitazone decreased ANG II-induced DNA synthesis. Rosiglitazone treatment increased nuclear PPAR-gamma expression and activity in VSMC. However, rosiglitazone did not alter expression of PPAR-alpha/beta, ERK 1/2, Akt, or ANG II receptors. 15d-PGJ2 and rosiglitazone decreased ERK 1/2 and Akt peak activity, both of which were induced by ANG II via the AT1 receptor. Rosiglitazone inhibited ANG II-enhanced phosphorylation of eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), as well as Src homology (SH) 2-containing inositol phosphatase 2 (SHIP2). PPAR-gamma activation reduced ANG II-induced growth associated with inhibition of ERK 1/2, Akt, 4E-BP1, and SHIP2. Modulation of these pathways by PPAR-gamma activators may contribute to regression of vascular remodeling in hypertension.     

Rosiglitazone is not associated with an increased risk of bladder cancer

BackgroundWhether rosiglitazone may increase bladder cancer risk has not been extensively investigated.MethodsThe reimbursement databases of all Taiwanese diabetic patients under oral anti-diabetic agents or insulin from 1996 to 2009 were retrieved from the National Health Insurance. An entry date was set at 1 January 2006 and a total of 885,236 patients with type 2 diabetes were followed up for bladder cancer incidence till end of 2009. Incidences for ever-users, never-users and subgroups of rosiglitazone exposure (using tertile cutoffs of time since starting rosiglitazone, duration of therapy and cumulative dose) were calculated and hazard ratios estimated by Cox regression.ResultsThere were 102,926 ever-users and 782,310 never-users, respective numbers of incident bladder cancer 356 (0.35%) and 2753 (0.35%), and respective incidence 98.3 and 101.6 per 100,000 person-years. The overall hazard ratios (95% confidence intervals) did not show significant association in unadjusted model [0.969 (0.867, 1.082)] and models adjusted for age and sex [0.983 (0.880, 1.098)] or all covariates [0.980 (0.870, 1.104)]. Neither the P values for the hazard ratios for the different categories of the dose–responsive parameters, nor their P-trends were significant.ConclusionsRosiglitazone does not increase the risk of bladder cancer.     

Reactivity of the aorta and mesenteric resistance arteries from the obese spontaneously hypertensive rat: effects of glitazones

The obese spontaneously hypertensive rat (SHROB) is a model of metabolic syndrome in which, to our knowledge, vascular function has never been studied. The actions of insulin sensitizers (glitazones) on vascular function have not been analyzed either. Our purpose was to characterize microvascular and macrovascular responses of the SHROB and to study the effects of glitazones on these responses. The reactivity of mesenteric resistance arteries (MRAs) and the aorta from SHROBs and control rats to cumulative concentrations of phenylephrine, ACh, and sodium nitroprusside (SNP) was myographically analyzed. Some animals were orally treated with rosiglitazone (3 mg·kg(-1)·day(-1), 3 wk), and myography was performed. Phenylephrine, ACh, and SNP dose-response curves were impaired to different extents in arteries of SHROBs. Incubation with N-nitro-L-arginine methyl ester caused little effects on phenylephrine and ACh curves in MRAs but enhanced phenylephrine contractions and abolished ACh-induced relaxations of aortae. Incubation with indomethacin reduced phenylephrine reactivity and improved ACh-induced relaxations of all vessels studied. NS-398 and tempol increased relaxations to ACh of MRAs. Incubation with pioglitazone or rosiglitazone (both 10(-5) M) or oral treatment with rosiglitazone improved, to different extents, ACh and SNP curves in all vessels. Glitazone incubation diminished aortic ACh sensitivity. The release of thromboxane A(2) and PGI(2) metabolites (thromboxane B(2) and 6-keto-PGF(1α)) was analyzed. ACh increased the MRA release of thromboxane B(2) from SHROBs but not control rats, and the former was prevented by rosiglitazone coincubation. In contrast, in aortae, ACh failed to alter the release of metabolites, and rosiglitazone treatment increased that of 6-keto-PGF(1α). Thus, SHROBs displayed microvascular and macrovascular dysfunction. MRAs, but not aortae, of SHROBs revealed an impaired endothelial nitric oxide pathway, whereas both, but especially MRAs, displayed an impaired cyclooxygenase pathway. Glitazones elicited beneficial effects on macrovascular and, especially, microvascular function of SHROBs.     

A pilot study of the effects of pioglitazone and rosiglitazone on de novo lipogenesis in type 2 diabetes

Treatment of type 2 diabetes mellitus (T2DM) patients with pioglitazone results in a more favorable lipid profile, and perhaps more favorable cardiac outcomes, than treatment with rosiglitazone. Pioglitazone treatment increases VLDL-triacylglycerol clearance, but the role of de novo lipogenesis (DNL) has not been explored, and no direct comparison has been made between the thiazolidinediones (TZDs). Twelve subjects with T2DM and hypertriacylglyceridemia were randomized to either rosiglitazone or pioglitazone treatment. Stable isotope infusion studies were performed at baseline and after 20 weeks of treatment. Both treatments reduced glucose and HbA(1c) concentrations equally. Pioglitazone treatment resulted in a 40% reduction in hepatic DNL (P < 0.01) and in a 25% reduction in hepatic glucose production (P < 0.05), while rosiglitazone did not significantly change either parameter, although comparisons of changes between treatments were not significantly different. These pilot results indicate that pioglitazone reduces hepatic DNL while rosiglitazone does not. Larger follow-up studies are required to confirm differential effects of these agents definitively. The reduction in DNL may underlie altered assembly or atherogenicity of lipoprotein particles and may reflect PPARalpha or other non-PPARgamma actions on the liver by pioglitazone. These differences might help explain previously reported differences in lipid profiles and cardiovascular disease outcomes for rosiglitazone and pioglitazone.     

Synthesis of N-trifluoroacetyl-L-acosamine, N-trifluoroacetyl-L-daunosamine, and their 1-thio analogs

A simple and efficient route to N-trifluoroacetyl-L-acosamine (13), N-trifluoroacetyl-L-daunosamine (12), and their 1-thio analogues (18 and 20) is described. Stereoselective reduction of oxime 5 with borane, followed by trifluoroacetylation resulted in the arabino methyl glycoside (8), which, on mild acid hydrolysis gave N-trifluoroacetyl-L-acosamine (13) in an overall yield of 33%, based on L-rhamnal (1). Upon oxidation of the C-4 hydroxyl group and stereoselective reduction of the resulting ketone 11, compound 8 of L-arabino configuration was converted into N-trifluoroacetyl-L-daunosamine (12) in a one-flask sequence with an overall yield of 28% calculated for 1. Benzyl 1-thio-N-trifluoroacetyl-alpha-L-acosaminide (18) was synthesized from enone 2 on Michael-type addition of phenylmethanethiol, followed by oximation, stereoselective reduction with borane and subsequent trifluoroacetylation. 4-O-Acetyl-1-S-acetyl-N-trifluoroacetyl-1-thio-beta-L-daunosamine 20 was prepared from 12 via the corresponding glycosyl chloride derivative.     

The PPARγ agonist rosiglitazone prevents neuronal loss and attenuates development of spontaneous recurrent seizures through BDNF/TrkB signaling following pilocarpine-induced status epilepticus

Hippocampal neuronal loss plays an important role in epileptogenesis, and it is considered a trigger of repeated spontaneous recurrent seizures (SRS). The BDNF/TrkB signaling pathway regulates neuronal plasticity in the CNS, and promotes epileptogenesis. Previous studies have shown that Peroxisome proliferator-activated receptor gamma (PPARγ) agonists exert neuroprotective effects by inhibiting oxidative stress and inflammation in epilepsy. In the present study, the PPARγ agonist rosiglitazone inhibited increases in BDNF and TrkB after status epilepticus (SE), and also prevented hippocampal neuronal loss. More importantly, our study showed that rosiglitazone suppressed SRS. However, the effects of rosiglitazone were significantly reversed by cotreatment with K252a, an antagonist of TrkB. Additionally, rosiglitazone did not affect the development and severity of SE. Thus, our data provide evidence that rosiglitazone exerts neuroprotective and antiepileptic effects involve BDNF/TrkB signaling. Our study also offers new perspectives for the treatment of epilepsy.     

Modulation of metabolic and cardiac dysfunctions by insulin sensitizers and angiotensin receptor blocker in rat model of type 2 diabetes mellitus

The objective of this study was to investigate the modulation of metabolic dysfunctions, adiponectin levels, and cardiac dysfunctions of type 2 diabetes mellitus (T2DM) by a combination of the insulin sensitizer rosiglitazone and angiotensin receptor blocker telmisartan in an experimental rat model. Fifty male adult Sprague-Dawley rats were divided equally into 5 groups. Group I: fed normal chow; served as normal control group. Groups II-V: fed a high-fat diet (HFD) for 2 weeks, followed by injection of streptozotocin (STZ; 35 mg/kg) to create a model of T2DM. Group II: treated with vehicle. Group III: treated with rosiglitazone (4 mg/kg). Group IV: treated with telmisartan (5 mg/kg). Group V: treated with both agents. Untreated HFD-STZ rats showed elevated fasting blood glucose, insulin, homeostasis model assessment (HOMA) index, triglycerides (TGs), low-density lipoprotein cholesterol (LDL), and total serum cholesterol (TC), with a decrease in high-density lipoprotein cholesterol (HDL) and adiponectin levels (p < 0.001). Rosiglitazone exerted more improvement in all parameters than telmisartan did, and a combination of both did not augment the improvement further, except for TGs and adiponectin. For the isolated atrial study, a combination of rosiglitazone and telmisartan corrected the responses of the atria of HFD-STZ rats to the negative inotropic effect induced by adenosine better than either one did alone, whereas this combination, surprisingly, significantly attenuated the positive inotropic response to β-adrenoreceptor and α-adrenoreceptor agonists. In conclusion, rosiglitazone significantly improved the metabolic and cardiac dysfunctions in T2DM. Moreover, a combination of rosiglitazone and telmisartan offered more improvement in serum TGs and adiponectin, and restored the atrial inotropic response to adenosine. Surprisingly, this combination significantly attenuates the positive inotropic response to α1-adrenoreceptor and β-adrenoreceptor agonists.