Antidiabetic PPAR gamma-activator rosiglitazone reduces MMP-9 serum levels in type 2 diabetic patients with coronary artery disease

Assessing the hepatoprotective effects of hesperidin on liver-associated disorders in albino rats with experimentally induced obesity and type II diabetes: A histological and biochemical study

Hesperidin (HSP) has multiple beneficial effects in verities of clinical situations including type 2 diabetes mellitus (T2DM).

AIM

Determination of curative effects of HSP on the liver in T2DM rats through biochemical and histopathological studies.

METHODS

Animals. Fifty rats were enrolled. 10 rats were fed a normal diet (control group), and the remaining 40 rats received a high-fat diet (HFD) for 8 weeks. The HFD-fed rats were grouped into Group II: 10 rats, and Group III: 10 rats received HSP 100 mg/kg. Group IV: 10 rats received a single dose of streptozotocin (STZ), 30 mg/kg, and Group V: 10 rats received STZ and HSP. Body weight, Blood glucose, insulin level, liver enzymes, lipid profile, oxidative stress, TNF-α, NF-κB, and liver biopsy were estimated.

RESULTS

there is improvement in the histological profile of the steatosis in HFD-fed rats treated with HSP either in group III or in group V (received STZ) along with amelioration in blood glucose, insulin, liver enzymes, lipid profile, oxidative profile, TNF-α, and NF-κB.

CONCLUSION

HSP in this STZ model revealed an improvement in steatosis, biochemical markers, and histologic findings. By studying these factors, we expected to identify the prospective targets for intervention that could help improve outcomes for individuals with obesity and diabetes-related liver diseases.

A phenome-wide comparative analysis of genetic discordance between obesity and type 2 diabetes

Obesity and type 2 diabetes are causally related, yet there is considerable heterogeneity in the consequences of both conditions and the mechanisms of action are poorly defined. Here we show a genetic-driven approach defining two obesity profiles that convey highly concordant and discordant diabetogenic effects. We annotate and then compare association signals for these profiles across clinical and molecular phenotypic layers. Key differences are identified in a wide range of traits, including cardiovascular mortality, fat distribution, liver metabolism, blood pressure, specific lipid fractions and blood levels of proteins involved in extracellular matrix remodelling. We find marginal differences in abundance of Bacteroidetes and Firmicutes bacteria in the gut. Instrumental analyses reveal prominent causal roles for waist-to-hip ratio, blood pressure and cholesterol content of high-density lipoprotein particles in the development of diabetes in obesity. We prioritize 17 genes from the discordant signature that convey protection against type 2 diabetes in obesity, which may represent logical targets for precision medicine approaches.

A novel layered double hydroxide-hesperidin nanoparticles exert antidiabetic, antioxidant and anti-inflammatory effects in rats with diabetes

BACKGROUND

Incidence of diabetes has increased significantly worldwide over recent decades. Our objective was to prepare and characterize a novel nano-carrier of hesperidin to achieve a sustained release of hesperidin and to explore the potency of the novel formula as an antidiabetic agent compared to metformin in type 2 diabetic rats.

METHODS

Hesperidin was loaded on MgAl-layered double hydroxide (LDH). The formula was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy, and dynamic light scattering. The release profile of hesperidin and MgAl-LDH-Hesperidin were studied in vitro. The parameters studied in vivo were blood glucose, glycated hemoglobin (HbA1c), insulin, lipid profile, and liver glycogen levels. We also investigated the levels of interleukin (IL)-17, tumor necrosis factor-Alfa (TNF-α), malondialdehyde (MDA), catalase, and the mRNA expression of peroxisome proliferator-activated receptor-gamma (PPARγ) and nuclear factor erythroid 2-related factor-2 (NrF2).

RESULTS

There were variations in the XRD patterns and FTIR confirming the physical adsorption of hesperidin on the surface of LDH. The results indicated that the diabetic rats treated with administration of antidiabetic formula, MgAl-LDH-Hesperidin, showed a beneficial effect on the levels of blood glucose, insulin, HbA1c%, and lipid profile, comparing to diabetic control rats. The antidiabetic agent also showed a significant decrease in the levels of TNF-α, IL-17, and MDA, and an increase in the level of catalase. Marked upregulation of the expression levels of mRNA for PPARγ and NrF2 were recorded.

CONCLUSION

The novel nano-hesperidin formula MgAl-LDH-Hesperidin revealed a sustained release of hesperidin and exhibited antidiabetic, antihyperlipidemic, antioxidant, and anti-inflammatory properties, and also is a promising agent for effective delivery of drugs to treat type 2 diabetes.

Yin-xing-tong-mai decoction attenuates atherosclerosis via activating PPARγ-LXRα-ABCA1/ABCG1 pathway

Atherosclerosis is now the major cause of mortality and morbidity worldwide. Formation of macrophage-derived foam cells is a hallmark of atherosclerosis, which is regulated by cholesterol uptake, intracellular metabolism, and efflux. PPARγ-LXRα-ABCA1/ABCG1 pathway plays an important part in regulating cholesterol efflux and this pathway could be a promising target for treating atherosclerosis. However, due to undesirable systemic effects, PPARγ agonist therapy for atherosclerosis remains challenging. Many traditional Chinese medicine has been well accepted and applied in atherosclerosis treatment. Yin-xing-tong-mai decoction (YXTMD) has been applied for treating atherosclerosis for decades. However, the mechanism remains to be explored. Here, we showed that YXTMD effectively attenuated atherosclerosis in ApoE^-/- mice. YXTMD increased cholesterol efflux of foam cell by upregulation of ABCA1 and ABCG1 in vivo and in vitro. Through bioinformatic analysis and experimental validation, we found that PPARγ was an important downstream effector of YXTMD in macrophages. Reduction of PPARγ significantly decreased LXRα, ABCA1, and ABCG1 expression in macrophages, with reduced cholesterol efflux. In conclusion, these findings confirmed that YXTMD attenuated atherosclerosis by activating the PPARγ-LXRα- ABCA1/ABCG1 pathway to enhance cholesterol efflux.

The Role of Matrix Metalloproteinase-9 in Atherosclerotic Plaque Instability

Matrix metalloproteinase-9 (MMP-9) belongs to the MMP family and has been widely investigated. Excessive MMP-9 expression can enhance extracellular matrix degradation and promote plaque instability. Studies have demonstrated that MMP-9 levels are higher in vulnerable plaques than in stable plaques. Additionally, several human studies have demonstrated that MMP-9 may be a predictor of atherosclerotic plaque instability and a risk factor for future adverse cardiovascular and cerebrovascular events. MMP-9 deficiency or blocking MMP-9 expression can inhibit plaque inflammation and prevent atherosclerotic plaque instability. All of these results suggest that MMP-9 may be a useful predictive biomarker for vulnerable atherosclerotic plaques, as well as a therapeutic target for preventing atherosclerotic plaque instability. In this review, we describe the structure, function, and regulation of MMP-9. We also discuss the role of MMP-9 in predicting and preventing atherosclerotic plaque instability.

Macrophage: A Key Therapeutic Target in Atherosclerosis?

Background:

Atherosclerosis is a chronic inflammatory disease and a leading cause of coronary artery disease, peripheral vascular disease and stroke. Lipid-laden macrophages are derived from circulating monocytes and form fatty streaks as the first step of atherogenesis.

Methods:

An electronic search in major databases was performed to review new therapeutic opportunities for influencing the inflammatory component of atherosclerosis based on monocytes/macrophages targeting.

Results:

In the past two decades, macrophages have been recognized as the main players in atherogenesis but also in its thrombotic complications. There is a growing interest in immunometabolism and recent studies on metabolism of macrophages have created new therapeutic options to treat atherosclerosis. Targeting recruitment, polarization, cytokine profile extracellular matrix remodeling, cholesterol metabolism, oxidative stress, inflammatory activity and non-coding RNAs of monocyte/macrophage have been proposed as potential therapeutic approaches against atherosclerosis.

Conclusion:

Monocytes/macrophages have a crucial role in progression and pathogenesis of atherosclerosis. Therefore, targeting monocyte/macrophage therapy in order to achieve anti-inflammatory effects might be a good option for prevention of atherosclerosis.

[Markers of Vascular Wall Fibrosis Metalloproteinase-9 and Tissue Inhibitor of Metalloproteinases-1 in Patients with Ischemic Heart Disease with and without Concomitant Type-2 Diabetes Mellitus]

The prevalence of ischemic heart disease (IHD) and diabetes mellitus type 2 (DM type 2) is permanently increasing both worldwide and in theRussian Federation. That is why studies of mechanisms of pathogenesis of both diseases is continuing for prevention of complications and mortality. DM type 2 contributes a lot to deterioration of IHD. One of pathogenetic features these two pathologies share is pronounced blood vessel wall fibrosis. In this review we present analysis of studies devoted to the determination of the role of metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 indevelopment of vascular wall fibrosis.

Serum amyloid A - a review

Serum amyloid A (SAA) proteins were isolated and named over 50 years ago. They are small (104 amino acids) and have a striking relationship to the acute phase response with serum levels rising as much as 1000-fold in 24 hours. SAA proteins are encoded in a family of closely-related genes and have been remarkably conserved throughout vertebrate evolution. Amino-terminal fragments of SAA can form highly organized, insoluble fibrils that accumulate in “secondary” amyloid disease. Despite their evolutionary preservation and dynamic synthesis pattern SAA proteins have lacked well-defined physiologic roles. However, considering an array of many, often unrelated, reports now permits a more coordinated perspective. Protein studies have elucidated basic SAA structure and fibril formation. Appreciating SAA’s lipophilicity helps relate it to lipid transport and metabolism as well as atherosclerosis. SAA’s function as a cytokine-like protein has become recognized in cell-cell communication as well as feedback in inflammatory, immunologic, neoplastic and protective pathways. SAA likely has a critical role in control and possibly propagation of the primordial acute phase response. Appreciating the many cellular and molecular interactions for SAA suggests possibilities for improved understanding of pathophysiology as well as treatment and disease prevention.

Comparison of the perioperative time courses of matrix metalloproteinase-9 (MMP-9) and its inhibitor (TIMP-1) during carotid artery stenting (CAS) and carotid endarterectomy (CEA)

Background

Our aim was to compare the perioperative time courses of matrix metalloproteinase-9 (MMP-9) and its inhibitor (TIMP-1) in during carotid endarterectomy (CEA) and carotid artery stenting (CAS).

Methods

In our prospective study, twenty-five patients who were scheduled to undergo CAS were enrolled. We used a matched, historical CEA group as controls. Blood samples were collected at four time points: T1: preoperative; T2: 60 min after stent insertion; T3: first postoperative morning; and T4: third postoperative morning. Plasma MMP-9 and TIMP-1 levels were measured by ELISA.

Results

In the CEA group, the plasma levels of MMP-9 were significantly elevated at T3 compared to T1. In the CAS group, there was no significant difference in MMP-9 levels in the perioperative period. MMP-9 levels were significantly higher in the T3 samples of the CEA group compared to the CAS group. Significantly lower TIMP-1 levels were measured in both groups at T2 than at T1 in both groups. MMP-9/TIMP-1 at T3 was significantly higher than that at T1 in the CEA group compared to both T1 and the CAS group.

Conclusions

CAS triggers smaller changes in the MMP-9-TIMP-1 system during the perioperative period, which may correlate with a lower incidence of central nervous system complications. Additional studies as well as cognitive and functional surveys are warranted to determine the clinical relevance of our findings.

Trial registration

NIH U.S. National Library of Medicine, Clinicaltrials.gov,NCT03410576, 24.01.2018, Retrospectively registered

Serum MMP-9 Diagnostics, Prognostics, and Activation in Acute Coronary Syndrome and Its Recurrence

Matrix metalloproteinase (MMP)-9 is crucial in atherosclerotic plaque rupture and tissue remodeling after a cardiac event. The balance between MMP-9 and endogenous inhibitor, tissue inhibitors of matrix metalloproteinase 1 (TIMP-1), is important in acute coronary syndrome (ACS). This is an age- and gender-matched case-control study of ACS (N = 669). Patients (45.7%) were resampled after recovery, and all were followed up for 6 years. The molecular forms of MMP-9 were investigated by gelatin zymography. Diagnostically, MMP-9 and the MMP-9/TIMP-1 molar ratio were associated with ACS (OR 5.81, 95% CI 2.65–12.76, and 4.96, 2.37–10.38). The MMP-9 concentrations decreased 49% during recovery (p < 0.001). The largest decrease of these biomarkers between acute and recovery phase (ΔMMP-9) protected the patients from major adverse cardiac events, especially the non-fatal events. The fatal events were associated with in vitro activatable MMP-9 levels (p = 0.028). Serum MMP-9 and the MMP-9/TIMP-1 molar ratio may be valuable in ACS diagnosis and prognosis. High serum MMP-9 activation potential is associated with poor cardiovascular outcome.

Therapeutic Effects of Targeted PPARɣ Activation on Inflamed High-Risk Plaques Assessed by Serial Optical Imaging In Vivo

Rationale: Atherosclerotic plaque is a chronic inflammatory disorder involving lipid accumulation within arterial walls. In particular, macrophages mediate plaque progression and rupture. While PPARγ agonist is known to have favorable pleiotropic effects on atherogenesis, its clinical application has been very limited due to undesirable systemic effects. We hypothesized that the specific delivery of a PPARγ agonist to inflamed plaques could reduce plaque burden and inflammation without systemic adverse effects.

Methods: Herein, we newly developed a macrophage mannose receptor (MMR)-targeted biocompatible nanocarrier loaded with lobeglitazone (MMR-Lobe), which is able to specifically activate PPARγ pathways within inflamed high-risk plaques, and investigated its anti-atherogenic and anti-inflammatory effects both in in vitro and in vivo experiments.

Results: MMR-Lobe had a high affinity to macrophage foam cells, and it could efficiently promote cholesterol efflux via LXRα-, ABCA1, and ABCG1 dependent pathways, and inhibit plaque protease expression. Using in vivo serial optical imaging of carotid artery, MMR-Lobe markedly reduced both plaque burden and inflammation in atherogenic mice without undesirable systemic effects. Comprehensive analysis of en face aorta by ex vivo imaging and immunostaining well corroborated the in vivo findings.

Conclusion: MMR-Lobe was able to activate PPARγ pathways within high-risk plaques and effectively reduce both plaque burden and inflammation. This novel targetable PPARγ activation in macrophages could be a promising therapeutic strategy for high-risk plaques.

ΔFosB regulates rosiglitazone-induced milk fat synthesis and cell survival

Rosiglitazone induces adipogenesis in adipocyte and regulates cell survival and differentiation in number of cell types. However, whether PPARγ regulates the synthesis of milk fat and cell survival in goat mammary gland remains unknown. Rosiglitazone strongly enhanced cellular triacylglycerol content and accumulation of lipid droplet in goat mammary epithelial cells (GMEC). Furthermore, ΔFosB decreased the expression of PPARγ at both mRNA and protein levels, and rosiglitazone-induced milk fat synthesis was abolished by ΔFosB overexpression. ΔFosB reduced milk fat synthesis and enhanced saturated fatty acid concentration. Rosiglitazone increased the number of GMEC in G0/G1 phase and inhibited cell proliferation, and these effects were improved by overexpression of ΔFosB. ΔFosB was found to promote the expression of Bcl-2 and suppress the expression of Bax, and protected GMEC from apoptosis induced by rosiglitazone. Intracellular calcium trafficking assay revealed that rosiglitazone markedly increased intracellular calcium concentration. ΔFosB protected GMEC from apoptosis induced by intracellular Ca²⁺ overload. ΔFosB increased MMP-9 gelatinolytic activity. SB-3CT, an MMP-9 inhibitor, suppressed the expression of Bcl-2, and increased intracellular calcium levels, and this effect was abolished by ΔFosB overexpression. SB-3CT induced GMEC apoptosis and this effect was inhibited by ΔFosB overexpression. These findings suggest that ΔFosB regulates rosiglitazone-induced milk fat synthesis and cell survival. Therefore, ΔFosB may be an important checkpoint to control milk fat synthesis and cell apoptosis.

Interactions between PPAR Gamma and the Canonical Wnt/Beta-Catenin Pathway in Type 2 Diabetes and Colon Cancer

In both colon cancer and type 2 diabetes, metabolic changes induced by upregulation of the Wnt/beta-catenin signaling and downregulation of peroxisome proliferator-activated receptor gamma (PPAR gamma) may help account for the frequent association of these two diseases. In both diseases, PPAR gamma is downregulated while the canonical Wnt/beta-catenin pathway is upregulated. In colon cancer, upregulation of the canonical Wnt system induces activation of pyruvate dehydrogenase kinase and deactivation of the pyruvate dehydrogenase complex. As a result, a large part of cytosolic pyruvate is converted into lactate through activation of lactate dehydrogenase. Lactate is extruded out of the cell by means of activation of monocarboxylate lactate transporter-1. This phenomenon is called Warburg effect. PPAR gamma agonists induce beta-catenin inhibition, while inhibition of the canonical Wnt/beta-catenin pathway activates PPAR gamma.

Attenuation of carotid neointimal formation after direct delivery of a recombinant adenovirus expressing glucagon-like peptide-1 in diabetic rats

AIMS

Enhancement of glucagon-like peptide-1 (GLP-1) reduces glucose levels and preserves pancreatic β-cell function, but its effect against restenosis is unknown.

METHODS AND RESULTS

We investigated the effect of subcutaneous injection of exenatide or local delivery of a recombinant adenovirus expressing GLP-1 (rAd-GLP-1) into carotid artery, in reducing the occurrence of restenosis following balloon injury. As a control, we inserted β-galactosidase cDNA in the same vector (rAd-βGAL). Otsuka Long-Evans Tokushima rats were assigned to three groups (n = 12 each): (1) normal saline plus rAd-βGAL delivery (NS + rAd-βGAL), (2) exenatide plus rAd-βGAL delivery (Exenatide + rAd-βGAL), and (3) normal saline plus rAd-GLP-1 delivery (NS + rAd-GLP-1). Normal saline or exenatide were administered subcutaneously from 1 week before to 2 weeks after carotid injury. After 3 weeks, the NS + rAd-βGAL group showed the highest intima-media ratio (IMR; 3.73 ± 0.90), the exenatide + rAd-βGAL treatment was the next highest (2.80 ± 0.51), and NS + rAd-GLP-1 treatment showed the lowest IMR (1.58 ± 0.48, P < 0.05 vs. others). The proliferation and migration of vascular smooth muscle cells and monocyte adhesion were decreased significantly after rAd-GLP-1 treatment, showing the same overall patterns as the IMR. In injured vessels, the apoptosis was greater and MMP2 expression was less in the NS + rAd-GLP-1 than in the exenatide or rAd-βGAL groups. In vitro expressions of matrix metalloproteinases-2 and monocyte chemoattractant protein-1 and nuclear factor-kappa-B-p65 translocation were decreased more in the NS + rAd-GLP-1 group than in the other two groups (all P < 0.05).

CONCLUSION

Direct GLP-1 overexpression showed better protection against restenosis after balloon injury via suppression of vascular smooth muscle cell migration, increased apoptosis, and decreased inflammatory processes than systemic exenatide treatment. This has potential therapeutic implications for treating macrovascular complications in diabetes.

Aortic stenting in the growing sheep causes aortic endothelial dysfunction but not hypertension: Clinical implications for coarctation repair

BACKGROUND

Stent implantation is the treatment of choice for adolescents and adults with aortic coarctation (CoAo). Despite excellent short-term results, 20%-40% of the patients develop arterial hypertension later in life, which was attributed to inappropriate response of the aortic baroreceptors to increased stiffness of the ascending aorta (ASAO), either congenital or induced by CoAo repair. In particular, it has been hypothesized that stent itself may cause or sustain hypertension. Therefore, we aimed to study the hemodynamic and structural impact following stent implantation in the normal aorta of a growing animal.

METHODS

Eight female sheep completed the study and a stent was implanted in four. Every 3 mo we measured blood pressure of the anterior and posterior limbs and left ventricular function by echocardiography. Twelve months later invasive pressure was measured under baseline and simulated stress conditions. Expression of genes indicating oxidative stress (OS), endothelial dysfunction (ED) and stiffness, as well as pathological examination were performed in ascending (ASAO) and descending aorta (DSAO).

RESULTS

SOD1 and MMP9 gene expression were higher in ASAO of the stented animals, compared to DSAO and controls, while NOS3 was decreased. No differences were found in blood pressure and echocardiographic parameters. No histological differences were found in the aorta of the two groups of animals.

CONCLUSIONS

Stent does not affect central and peripheral hemodynamics, cardiac structure and function even in the long term. However, the finding of markers of OS and increased stiffness of ASAO, proximal to the stent, points to molecular mechanisms for increased cardiovascular risk of patients with stented CoAo.

Review: Vascular protective effects of peroxisome proliferator-activated receptor agonists

ardiovascular disease is significantly increased in patients with the metabolic syndrome and type 2 diabetes. A clustering of risk factors, including dyslipidaemia, insulin resistance, hypertension, inflammation and coagulation disorders are acting in concert to promote cardiovascular events in these patients. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that influence vascular function by altering gene expression in vascular tissue and indirectly via effects on other tissues. Indeed, PPAR activation displays beneficial effects on glucose homeostasis and lipid metabolism, and also on endothelial function and vessel wall inflammation. Clinically used PPARα agonists, such as fibrates, and PPARγ agonists, such as insulin-sensitising thiazolidinediones, may consequently alter the process of atherosclerosis, especially in subjects with the metabolic syndrome and type 2 diabetes. The present review highlights emerging evidence for beneficial effects of PPAR α and PPARγ in the prevention and treatment of atherosclerosis in such high-risk patients.

Review: The metabolic syndrome as an endocrine disease: is there an effective pharmacotherapeutic strategy optimally targeting the pathogenesis?

The metabolic syndrome (MetS) represents a combination of cardiovascular risk determinants such as obesity, insulin resistance and lipid abnormalities such as hypertriglyceridemia, increased free fatty acids, low high-density-cholesterol and hypertension. As a multiple component condition it imparts a doubling of relative risk for atherosclerotic cardiovascular disease (ASCVD). It is currently controversial which component of the syndrome carries what weight. There is even a considerable debate whether the risk for ASCVD is greater in patients diagnosed with MetS than that by the individual risk factors. At present, no unifying pathogenetic mechanism can explain the metabolic syndrome and there is no unique treatment for it. This review summarizes and critically reviews the currently available clinical and scientific evidence for the concept that the MetS is causally an endocrine disease and discusses pharmacotherapeutic strategies targeting the pathogenesis rather than single symptoms of the cluster.

Thiazolidinediones and inflammation

Thiazolidinediones (TZDs) are selective ligands of peroxisome-proliferator-activated receptor g increasingly used in the treatment of type 2 diabetes. Both in vitro and in vivo studies provide evidence that TZDs have anti-inflammatory properties. TZDs inhibit macrophage activation and decrease inflammatory cytokine expression and release in macrophage and monocyte. In vivo, treatment with TZDs decreases circulating mononuclear cells nuclear NF-kB content while increasing, in the same cells, expression of IkB, an NK-kB inhibitor. Furthermore, TZD treatment results in decreased plasma levels of inflammation and cardiovascular risk markers such as CRP, MMP9, PAI-1 and sCD40 in both obese and type 2 diabetic patients. Finally, TZDs induce synoviocyte apoptosis and reduce secretion of TNFa, IL-6 and IL-8 in synoviocyte from rheumatoid arthritis patients. TZDs might thus be considered for use in clinical trials targeting prevention of atherosclerosis and cardiovascular diseases and in pilot trials exploring the possibility that TZDs might help in the treatment of rheumatic diseases.

An M1-like Macrophage Polarization in Decidual Tissue during Spontaneous Preterm Labor That Is Attenuated by Rosiglitazone Treatment

Decidual macrophages are implicated in the local inflammatory response that accompanies spontaneous preterm labor/birth; however, their role is poorly understood. We hypothesized that decidual macrophages undergo a proinflammatory (M1) polarization during spontaneous preterm labor and that PPARγ activation via rosiglitazone (RSG) would attenuate the macrophage-mediated inflammatory response, preventing preterm birth. In this study, we show that: 1) decidual macrophages undergo an M1-like polarization during spontaneous term and preterm labor; 2) anti-inflammatory (M2)-like macrophages are more abundant than M1-like macrophages in decidual tissue; 3) decidual M2-like macrophages are reduced in preterm pregnancies compared with term pregnancies, regardless of the presence of labor; 4) decidual macrophages express high levels of TNF and IL-12 but low levels of peroxisome proliferator-activated receptor γ (PPARγ) during spontaneous preterm labor; 5) decidual macrophages from women who underwent spontaneous preterm labor display plasticity by M1↔M2 polarization in vitro; 6) incubation with RSG reduces the expression of TNF and IL-12 in decidual macrophages from women who underwent spontaneous preterm labor; and 7) treatment with RSG reduces the rate of LPS-induced preterm birth and improves neonatal outcomes by reducing the systemic proinflammatory response and downregulating mRNA and protein expression of NF-κB, TNF, and IL-10 in decidual and myometrial macrophages in C57BL/6J mice. In summary, we demonstrated that decidual M1-like macrophages are associated with spontaneous preterm labor and that PPARγ activation via RSG can attenuate the macrophage-mediated proinflammatory response, preventing preterm birth and improving neonatal outcomes. These findings suggest that the PPARγ pathway is a new molecular target for future preventative strategies for spontaneous preterm labor/birth.

Effects of obesity on the association between common variations in the TBX5 gene and matrix metalloproteinase 9 levels in Taiwanese

Objectives:

The TBX5 gene, a member of the T-box family, is associated with congenital heart disease, electrocardiographic parameters, and development of atrial fibrillation in the general population. This study aimed to elucidate the role of TBX5 gene polymorphisms in metabolic and inflammatory profiles possibly linked to TBX5-related pathologies.

Materials and Methods:

A sample population of 597 individuals having routine health examinations was enrolled. Five tagging TBX5 single nucleotide polymorphisms (SNPs) were analyzed using polymerase chain reaction and restriction enzyme digestion or TaqMan SNP genotyping assays. Associations between genotypes/haplotypes and matrix metalloproteinase 9 (MMP9) levels were investigated using generalized linear model analysis. Interactions between each genotype/haplotype, MMP9 level, and obesity status were tested using two-way analysis of variance with Golden Helix SVS Win32 7.3.1 software.

Results:

After adjusting for clinical covariates, TBX5 genotypes were found to be associated with MMP9 levels (p = 0.002 and p = 0.001 for rs4113925 and rs3825214, respectively) in a dominant inheritance model. Haplotype analysis using three tag SNPs (rs11067101, rs1247973, and rs3825214) revealed a significant association between TBX5 haplotype GCG and MMP9 levels (uncorrected p = 0.0093 and the corrected false discovery rate p = 0.0435). Multivariate analysis identified that SNP rs3825214, in addition to the MMP9 and E-selectin genotypes, was independently associated with MMP9 levels (p < 0.001). Using a dominant inheritance model, subgroup and interaction analysis showed associations between the rs4113925, rs3825214, and MMP9 levels only in nonobese individuals (p = 1.04 × 10⁻⁴ and p = 7.11 × 10⁻⁵, respectively; interaction p = 0.009 and 0.018, respectively). Subgroup analysis showed a borderline significant association between haplotype GCG and MMP9 levels (uncorrected p = 0.020 and corrected false discovery rate p = 0.073), but with no evidence of interaction.

Conclusion:

TBX5 genotypes/haplotypes are independently associated with MMP9 in Taiwanese individuals and occur predominantly in nonobese people. These associations may broaden our understanding of the mechanism underlying T-box family gene activity and related cardiovascular pathologies.

Effect of Atorvastatin and Pioglitazone on Plasma Levels of Adhesion Molecules in Non-Diabetic Patients With Hypertension or Stable Angina or Both

BACKGROUND

It was to study the effect of atorvastatin, pioglitazone and their combination on plasma levels of adhesion molecules in patients with hypertension or stable angina or both.

METHODS

It was an open-label, randomized parallel-group study. Forty-five atorvastatin-naive patients with hypertension or stable angina or both, were randomized to receive either atorvastatin (19 patients; 10 mg OD for 12 weeks) or pioglitazone (26 patients; 30 mg OD for 12 weeks). Another group of 30 patients who were already on atorvastatin were put on add-on pioglitazone therapy (pioglitazone (15 mg OD) + atorvastatin (10 mg OD) for 12 weeks). Plasma high-sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) levels were measured at baseline and after 12 weeks of therapy.

RESULTS

Atorvastatin monotherapy significantly reduced plasma sICAM-1, but pioglitazone monotherapy did not produce any significant effect. Addition of pioglitazone in patients already receiving atorvastatin also significantly reduced plasma sICAM-1 level. However, there was no significant change in plasma hsCRP and sVCAM-1 levels in any of the groups after 12 weeks of therapy.

CONCLUSION

There is therapeutic advantage of combining pioglitazone and atorvastatin on plasma sICAM-1 levels.

Rosiglitazone attenuates the metalloprotease/anti-metalloprotease imbalance in emphysema induced by cigarette smoke: involvement of extracellular signal-regulated kinase and NFκB signaling

Objective

We investigated how rosiglitazone attenuated cigarette smoke (CS)-induced emphysema in a rat model. In particular, we focused on its possible effects on the imbalance between metalloprotease (MMP) and anti-MMP activity, mitogen-activated protein kinase (MAPK) phosphorylation, and nuclear factor kappa-light-chain-enhancer of activated B cell (NFκB) signaling pathway over-activation.

Methods

A total of 36 Wistar rats were divided into three groups (n=12 each): animals were exposed to CS for 12 weeks in the absence (the CS group) or presence of 30 mg/kg rosiglitazone (the rosiglitazone-CS [RCS] group); a control group was treated with the rosiglitazone vehicle only, without any CS exposure. Histopathology of lung tissue in all groups was evaluated to grade severity of the disease. Expression levels of peroxisome proliferator-activated receptor γ (PPARγ), MMP2, and MMP9 in lung tissue were determined and compared using Western blotting and immunohistochemistry. Activation of MAPKs, NFκB, and the nuclear factor of kappa light polypeptide gene enhancer in B-cell inhibitor, alpha (IκBα) phosphorylation in lung tissue was examined by Western blotting.

Results

Emphysema-related pathology, based on inter-alveolar wall distance and alveolar density, was less severe in the RCS group than in the CS group. Compared with the CS group, levels of PPARγ were higher in the RCS group, and levels of MMP2 and MMP9 proteins were lower in the RCS rats. Levels of activated MAPKs and NFκB were also lower, while the IκBαphosphorylation was increased in the lung tissue of RCS rats.

Conclusion

Our findings suggest that oral administration of rosiglitazone attenuates the metalloprotease activity induced by CS, and the underlying mechanism might involve the activation of signaling pathways dependent on MAPKs or NFκB. Our results further suggest that PPARγ contributes to the pathogenesis of emphysema as well as airway inflammation induced by CS.

Protective effect of boswellic acids versus pioglitazone in a rat model of diet-induced non-alcoholic fatty liver disease: influence on insulin resistance and energy expenditure

Non-alcoholic fatty liver disease (NAFLD) is closely linked to insulin resistance, oxidative stress, and cytokine imbalance. Boswellic acids, a series of pentacyclic triterpene molecules that are produced by plants in the genus Boswellia, has been traditionally used for the treatment of a variety of diseases. This study aimed at evaluating the protective effect of boswellic acids in a model of diet-induced NAFLD in rats in comparison to the standard insulin sensitizer, pioglitazone. Rats were fed with a high-fat diet (HFD) for 12 weeks to induce NAFLD. Starting from week 5, rats received boswellic acids (125 or 250 mg/kg) or pioglitazone parallel to the HFD. Feeding with HFD induced hepatic steatosis and inflammation in rats. In addition, liver index, insulin resistance index, activities of liver enzymes, and serum lipids deviated from normal. Further, serum tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and cyclooxygenase 2 were elevated; this was associated with an increase in hepatic expression of inducible nitric oxide synthase (iNOS) and formation of 4-hydroxy-2-nonenal (HNE). Rats treated with boswellic acids (125 or 250 mg/kg) or pioglitazone showed improved insulin sensitivity and a reduction in liver index, activities of liver enzymes, serum TNF-α and IL-6 as well as hepatic iNOS expression and HNE formation compared to HFD group. Furthermore, at the cellular level, boswellic acids (250 mg/kg) ameliorated the expression of thermogenesis-related mitochondrial uncoupling protein-1 and carnitine palmitoyl transferase-1 in white adipose tissues. Data from this study indicated that boswellic acids might be a promising therapy in the clinical management of NAFLD if appropriate safety and efficacy data are available.

Hydroalcohol extract of Trigonella foenum-graecum seed attenuates markers of inflammation and oxidative stress while improving exocrine function in diabetic rats

CONTEXT AND OBJECTIVE

The herb fenugreek, Trigonella foenum-graecum Linn (Fabaceae), seeds have been traditionally used in the treatment of diabetes but its effect on oxidative stress and pro-inflammatory cytokines in the improvement of exocrine function of diabetes has not been studied. The effect of hydroalcoholic extract of Trigonella foenum-graecum seeds (HEF) on alloxan-induced type-II diabetic rat model was investigated.

MATERIALS AND METHODS

Effect of HEF (500, 1000, and 2000 mg/kg), glimepiride (4 mg/kg), and combination of HEF (500 mg/kg) + glimepiride (2 mg/kg), on alloxan-induced diabetic rats was evaluated by assaying (blood glucose, serum protein, glycosylated hemoglobin, muscle and liver glycogen, glucose uptake by diaphragm, liver glucose transport, serum pancreatic enzymes (α-amylase, lipase), pro-inflammatory cytokines (TNF-α, IL-6), antioxidant enzymes [glutathione (GSH), superoxide dismutase (SOD)], lipid peroxides (liver and pancreas), and histoarchitecture (liver, pancreas).

RESULTS

Treatment with HEF (at different doses), glimepiride, and HEF + glimepiride increased body weight and glucose uptake, reduced plasma glucose, glycosylated hemoglobin, liver glucose transport, pro-inflammatory cytokines, pancreatic enzymes and restored depleted glycogen (muscle, liver) and total protein significantly (p < 0.01) and dose dependently, including prevention of lipid peroxidation and restoration of GSH and SOD (liver and pancreas). Treatment with HEF + glimepiride potentiated hypoglycemic activity of glimepiride. Histoarchitecture of liver and pancreas showed marked improvement.

CONCLUSION

Present experimental findings suggest that HEF possesses promising hypoglycemic activity, presumably by amelioration of oxidative stress and pro-inflammatory cytokines. HEF may be useful as an adjuvant with clinically effective antidiabetic drugs in the management of type-II diabetes.

Vascular extracellular matrix in atherosclerosis

The extracellular matrix (ECM) is an essential component of the human body that is responsible for the proper function of various organs. Changes in the ECM have been implicated in the pathogenesis of several cardiovascular conditions including atherosclerosis, restenosis, and heart failure. Matrix components, such as collagens and noncollagenous proteins, influence the function and activity of vascular cells, particularly vascular smooth muscle cells and macrophages. Matrix proteins have been shown to be implicated in the development of atherosclerotic complications, such as plaque rupture, aneurysm formation, and calcification. ECM proteins control ECM remodeling through feedback signaling to matrix metalloproteinases (MMPs), which are the key players of ECM remodeling in both normal and pathological conditions. The production of MMPs is closely related to the development of an inflammatory response and is subjected to significant changes at different stages of atherosclerosis. Indeed, blood levels of circulating MMPs may be useful for the assessment of the inflammatory activity in atherosclerosis and the prediction of cardiovascular risk. The availability of a wide variety of low-molecular MMP inhibitors that can be conjugated with various labels provides a good perspective for specific targeting of MMPs and implementation of imaging techniques to visualize MMP activity in atherosclerotic plaques and, most interestingly, to monitor responses to antiatheroslerosis therapies. Finally, because of the crucial role of ECM in cardiovascular repair, the regenerative potential of ECM could be successfully used in constructing engineered scaffolds and vessels that mimic properties of the natural ECM and consist of the native ECM components or composite biomaterials. These scaffolds possess a great promise in vascular tissue engineering.

Telmisartan exerts anti-tumor effects by activating peroxisome proliferator-activated receptor-γ in human lung adenocarcinoma A549 cells

Telmisartan, a member of the angiotensin II type 1 receptor blockers, is usually used for cardiovascular diseases. Recent studies have showed that telmisartan has the property of PPARγ activation. Meanwhile, PPARγ is essential for tumor proliferation, invasion and metastasis. In this work we explore whether telmisartan could exert anti-tumor effects through PPARγ activation in A549 cells. MTT and trypan blue exclusion assays were included to determine the survival rates and cell viabilities. RT-PCR and western blotting were used to analyze the expression of ICAM-1, MMP-9 and PPARγ. DNA binding activity of PPARγ was evaluated by EMSA. Our data showed that the survival rates and cell viabilities of A549 cells were all reduced by telmisartan in a time- and concentration-dependent manner. Meanwhile, our results also demonstrated that telmisartan dose-dependently inhibited the expression of ICAM-1 and MMP-9. Moreover, the cytotoxic and anti-proliferative effects, ICAM-1 and MMP-9 inhibitive properties of telmisartan were totally blunted by the PPARγ antagonist GW9662. Our findings also showed that the expression of PPARγ was up-regulated by telmisartan in a dose dependent manner. And, the EMSA results also figured out that DNA binding activity of PPARγ was dose-dependently increased by telmisartan. Additionally, our data also revealed that telmisartan-induced PPARγ activation was abrogated by GW9662. Taken together, our results indicated that telmisartan inhibited the expression of ICAM-1 and MMP-9 in A549 cells, very likely through the up-regulation of PPARγ synthesis.

Matrix metalloproteinases in coronary artery disease

Matrix metalloproteinases (MMP) are a family of zinc-containing endoproteinases that degrade extracellular matrix (ECM) components. MMP have important roles in the development, physiology and pathology of cardiovascular system. Metalloproteases also play key roles in adverse cardiovascular remodeling, atherosclerotic plaque formation and plaque instability, vascular smooth muscle cell (SMC) migration and restenosis that lead to coronary artery disease (CAD), and progressive heart failure. The study of MMP in developing animal model cardiovascular systems has been helpful in deciphering numerous pathologic conditions in humans. Increased peripheral blood MMP-2 and MMP-9 in acute coronary syndrome (ACS) may be useful as noninvasive tests for detection of plaque vulnerability. MMP function can be modulated by certain pharmacological drugs that can be exploited for treatment of ACS. CAD is a polygenic disease and hundreds of genes contribute toward its predisposition. A large number of sequence variations in MMP genes have been identified. Case-control association studies have highlighted their potential association with CAD and its clinical manifestations. Although results thus far are inconsistent, meta-analysis has demonstrated that MMP-3 Glu45Lys and MMP-9 1562C/T gene polymorphisms were associated with CAD risk.

CNX-013-B2, a unique pan tissue acting rexinoid, modulates several nuclear receptors and controls multiple risk factors of the metabolic syndrome without risk of hypertriglyceridemia, hepatomegaly and body weight gain in animal models

BACKGROUND

In addition to their role in growth, cellular differentiation and homeostasis Retinoid X Receptors (RXR) regulate multiple physiological and metabolic pathways in various organs that have beneficial glucose and lipid (cholesterol) lowering, insulin sensitizing and anti-obesity effects. Rexinoids, compounds that specifically binds and activate RXR, are therefore considered as potential therapeutics for treating metabolic syndrome. Apparently many of the rexinoids developed in the past increased triglycerides, caused hepatomegaly and also suppressed the thyroid hormone axis. The aim of this study is to evaluate CNX-013-B2, a potent and highly selective rexinoid, for its potential to treat multiple risk factors of the metabolic syndrome.

METHODS

CNX-013-B2 was selected in a screening system designed to identify compounds that selectively activated only a chosen sub-set of heterodimer partners of RXR of importance to treat insulin resistance. Male C57BL/6j mice (n = 10) on high fat diet (HFD) and 16 week old ob/ob mice (n = 8) were treated orally with CNX-013-B2 (10 mg/kg twice daily) or vehicle for 10 weeks and 4 weeks respectively. Measurement of plasma glucose, triglyceride, cholesterol including LDL-C, glycerol, free fatty acids, feed intake, body weight, oral glucose tolerance and non-shivering thermogenesis were performed at selected time points. After study termination such measurements as organ weight, triglyceride content, mRNA levels, protein phosphorylation along with histological analysis were performed.

RESULTS

CNX-013-B2 selectively activates PPARs- α, β/δ and γ and modulates activity of LXR, THR and FXR. In ob/ob mice a significant reduction of 25% in fed glucose (p < 0.001 ), a 14% (p < 0.05) reduction in serum total cholesterol and 18% decrease (p < 0.01) in LDL-C and in DIO mice a reduction of 12% (p < 0.01 ) in fasting glucose, 20% in fed triglyceride (p < 0.01) and total cholesterol (p < 0.001) levels, coupled with enhanced insulin sensitivity, cold induced thermogenesis and 7% reduction in body weight were observed.

CONCLUSION

CNX-013-B2 is an orally bio available selective rexinoid that can be used as a novel therapeutic agent for management of multiple risk factors of the metabolic syndrome without the risk of side effects reported to be associated with rexinoids.

Preventive effect of irbesartan on bleomycin-induced lung injury in mice

BACKGROUND

Idiopathic pulmonary fibrosis is a specific form of chronic fibrosing interstitial pneumonia that is limited to the lung. Angiotensin receptor blockers (ARBs) and peroxisome proliferator-activated receptor (PPAR) γ ligands have anti-inflammatory and anti-fibrotic effects. We investigated the effects of irbesartan-an ARB with PPAR γ activity-on the development of bleomycin-induced pulmonary fibrosis in mice.

METHODS

Lung injury was induced in imprinting control region (ICR) mice by intratracheal instillation of 2mg/kg of bleomycin. The treatment group orally received 20mg/kg of irbesartan for 5 consecutive days before instillation. The mice were sacrificed and were evaluated 14 days after bleomycin instillation.

RESULTS

Irbesartan reduced the fluid content and hydroxyproline level in the lung and improved the pathological findings as indicated by the Ashcroft score. Total cell counts, the numbers of macrophages, neutrophils, and lymphocytes, and the levels of transforming growth factor (TGF) β1 and monocyte chemotactic protein (MCP) 1 in the bronchoalveolar lavage fluid (BALF) were decreased. Treatment with a PPARγ antagonist GW9662 reversed some of the effects of irbesartan.

CONCLUSIONS

The results of this study indicated that irbesartan attenuated the development of bleomycin-induced pulmonary fibrosis in mice by decreasing TGF-β1 and MCP-1 via blocking of ATI, by binding to CCR2b, and by PPARγ-mediated inhibition of inflammation.

Association of SELE genotypes/haplotypes with sE-selectin levels in Taiwanese individuals: interactive effect of MMP9 level

Background

E-selectin is implicated in various inflammatory processes and related disorders. We aimed to investigate the role of SELE-gene genotypes/haplotypes on plasma levels of MMP9 and sE-selectin in Taiwanese individuals.

Methods

Five hundred twenty individuals were enrolled. Seven tagging SELE single nucleotide polymorphisms were analyzed.

Results

SELE genotypes were found associated with MMP9 and sE-selectin levels. Multivariate analysis identified that the most significant genetic polymorphism (rs5368 genotype) was independently associated with MMP9 levels (P < 0.001). One haplotype (GGAGAGT) was marginally associated with MMP9 levels (P = 0.0490). One SELE SNP, (rs3917406, P = 0.031) was associated with sE-selectin levels after adjusting for MMP9 and sICAM1 levels. Subgroup and interaction analysis revealed association of SELE SNP rs10800469 with sE-selectin levels only in the highest quartile of MMP9 level (P = 0.002, interaction P = 0.023). Haplotype analysis showed one haplotype (AAAAAGC) borderline associated with sE-selectin level (P = 0.0511).

Conclusion

SELE genotypes/haplotypes are independently associated with MMP9 and E-selectin levels in Taiwanese individuals. The associations of SELE genotypes/haplotypes with sE-selectin levels are affected by MMP9 levels.

Hesperidin and naringin attenuate hyperglycemia-mediated oxidative stress and proinflammatory cytokine production in high fat fed/streptozotocin-induced type 2 diabetic rats

Abnormal regulation of glucose and impaired carbohydrate utilization that result from a defective or deficient insulin are the key pathogenic events in type 2 diabetes mellitus (T2DM). The present study was hypothesized to investigate the beneficial effects of hesperidin and naringin on hyperglycemia-induced oxidative damage in HFD/STZ-induced diabetic rats. Diabetes was induced by feeding rats with an HFD for 2 weeks followed by an intraperitoneal injection of STZ (35 mg/kg body weight). An oral dose of 50mg/kg hesperidin or naringin was daily given for 4 weeks after diabetes induction. At the end of the experimental period, blood was obtained from jugular vein and livers were rapidly excised and homogenized for biochemical assays. In the diabetic control group, levels of glucose, glycosylated hemoglobin (HbA1c%), MDA, NO, TNF-α and IL-6 were significantly increased, while serum insulin, GSH, vitamin C, and vitamin E levels were decreased. Both hesperidin and naringin administration significantly reversed these alterations. Moreover, supplementation with either compound significantly ameliorated serum and liver MDA, NO and glutathione, and liver antioxidant enzymes. Although detailed studies are required for the evaluation of the exact mechanism of the ameliorative effects of hesperidin and naringin against diabetic complications, these preliminary experimental findings demonstrate that both hesperidin and naringin exhibit antidiabetic effects in a rat model of T2DM by potentiating the antioxidant defense system and suppressing proinflammatory cytokine production.

Up-regulation of myocardial connexin-43 in spontaneously hypertensive rats fed red palm oil is most likely implicated in its anti-arrhythmic effects

The purpose of this study was to test our hypothesis that red palm oil (RPO) intake may affect abnormalities of myocardial connexin-43 (Cx43) and protein kinase Cε (PKCε) signaling, and consequently the propensity of the spontaneously hypertensive rat heart (SHR) heart to arrhythmias. SHR and Wistar-Kyoto (WKY) rats fed a standard rat chow plus red palm oil (200 µL/day) for 5 weeks were compared with untreated rats. Cytosolic but not particulate PKCε expression as well as Cx43-mRNA, total Cx43 proteins, and its phoshorylated forms were increased, and disordered localization of Cx43 was attenuated in the left ventricle of RPO-fed SHR compared with untreated rats. These alterations were associated with suppression of early post-ischemic-reperfusion-related ventricular tachycardia and electrically inducible ventricular fibrillation. However, the treatment dose of RPO caused down-regulation of myocardial Cx43, but did not alter its cell membrane distribution or overall PKCε expression in WKY rats. It was, however, associated with poor arrhythmia protection, suggesting overdosing. Results indicate that SHR benefit from RPO intake, particularly because of its apparent anti-arrhythmic effects. This protection can be, in part, attributed to the preservation of cell-to-cell communication via up-regulation of myocardial Cx43, but not with PKCε activation.

Peroxisome proliferator-activated receptor-gamma expression in monocytes/macrophages from rheumatoid arthritis patients: relation to disease activity and therapy efficacy--a pilot study

OBJECTIVES

Peroxisome proliferator-activated receptor-gamma (PPARγ) is expressed by different cell types in the joints and plays a relevant anti-inflammatory role in various diseases. This pilot study aimed to evaluate PPARγ expression in monocytes/macrophages isolated from RA patients as compared with healthy subjects, the relationships between PPARγ expression, MMP-9 activity and disease, and the influence of therapy with anti-rheumatic drugs on these parameters.

METHODS

Thirty RA patients of both sexes (treated with CSs and MTX, mainly) and 15 healthy volunteers were enrolled in this study. Disease severity was evaluated by the 28-joint disease activity score (DAS-28). Monocytes and monocyte-derived macrophages (MDMs) were isolated by standard procedures. PPARγ protein and mRNA expression were assessed by immunoblotting and real-time PCR, respectively; MMP-9 activity was determined by gelatin zymography. Moreover, we checked the ability of 15-deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ, a PPARγ agonist), MTX and methylprednisolone (MP) to affect PPARγ expression and lipopolysaccharide (LPS)-induced MMP-9 activity.

RESULTS

Monocytes/MDMs from RA patients have significantly enhanced PPARγ expression (both protein and mRNA) and MMP-9 activity as compared with healthy donors. Interestingly, cells from patients with less active disease (DAS-28 <3.2) present higher PPARγ protein expression and lower MMP-9 activity than RA patients with DAS-28 >3.2. At therapeutic concentrations, MTX and MP increase in vitro PPARγ protein expression and inhibit LPS-induced MMP-9 activity.

CONCLUSION

PPARγ expression in human monocytes/MDMs could represent an indicator of disease activity and therapy efficacy in RA because patients with a DAS-28 score <3.2 show the highest expression.

The effects of PPARγ agonist rosiglitazone on neointimal hyperplasia in rabbit carotid anastomosis model

Background

Neointimal hyperplasia involving smooth muscle cell (SMC) proliferation, migration and extracellular matrix (ECM) degradation is an important component of atherosclerosis. It develops as a response to vascular injury after balloon angioplasty and vascular graft placement. Matrix metalloproteinases (MMPs) induce SMC proliferation, migration and contribute to intimal hyperplasia by degrading ECM. PPARγ agonists inhibit SMC proliferation, migration and lesion formation. In this study, we aimed to investigate the effects of PPARγ agonist rosiglitazone on neointimal hyperplasia and gelatinase (MMP-2 and MMP-9) expressions in rabbit carotid anastomosis model.

Methods

New Zealand white rabbits (n = 13, 2.7–3.2 kg) were divided into placebo and treatment groups. Right carotid artery (CA) was transected and both ends were anastomosed. Treatment group (n = 6) received rosiglitazone (3 mg/kg/day/p.o.) and placebo group (n = 7) received PBS (phosphate buffered saline, 2.5 ml/kg/day/p.o.) for 4 weeks postoperatively. After the sacrification, right and left CAs were isolated. Morphometric analyses and immunohistochemical examinations for gelatinases were performed.

Results

Intimal area (0.055 ± 0.005 control vs 0.291 ± 0.020 μm² anastomosed, p < 0,05) and index (0.117 ± 0.002 control vs 0.574 ± 0.013 anastomosed, p < 0,01) significantly increased in anastomosed arteries compared to control arteries from placebo group. However, in rosiglitazone-treated group, intimal area (0.291 ± 0.020 PBS vs 0.143 ± 0.027 rosiglitazone, p < 0,05) and index (0.574 ± 0.013 PBS vs 0.263 ± 0.0078 rosiglitazone, p < 0,01) significantly decreased. Furthermore, gelatinase immunopositivity was found to have significantly increased in anastomosed arteries from placebo group and decreased with rosiglitazone treatment.

Conclusions

These results suggest that rosiglitazone may prevent neointimal hyperplasia, which is the most important factor involved in late graft failure, by inhibiting gelatinase enzyme expression.

Effect of a dipeptidyl peptidase-IV inhibitor, des-fluoro-sitagliptin, on neointimal formation after balloon injury in rats

BACKGROUND

Recently, it has been suggested that enhancement of incretin effect improves cardiac function. We investigated the effect of a DPP-IV inhibitor, des-fluoro-sitagliptin, in reducing occurrence of restenosis in carotid artery in response to balloon injury and the related mechanisms.

METHODS AND FINDINGS

Otsuka Long-Evans Tokushima Fatty rats were grouped into four: control (normal saline) and sitagliptin 100, 250 and 500 mg/kg per day (n = 10 per group). Sitagliptin or normal saline were given orally from 1 week before to 2 weeks after carotid injury. After 3 weeks of treatment, sitagliptin treatment caused a significant and dose-dependent reduction in intima-media ratio (IMR) in obese diabetic rats. This effect was accompanied by improved glucose homeostasis, decreased circulating levels of high-sensitivity C-reactive protein (hsCRP) and increased adiponectin level. Moreover, decreased IMR was correlated significantly with reduced hsCRP, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels and plasminogen activator inhibitor-1 activity. In vitro evidence with vascular smooth muscle cells (VSMCs) demonstrated that proliferation and migration were decreased significantly after sitagliptin treatment. In addition, sitagliptin increased caspase-3 activity and decreased monocyte adhesion and NFκB activation in VSMCs.

CONCLUSIONS

Sitagliptin has protective properties against restenosis after carotid injury and therapeutic implications for treating macrovascular complications of diabetes.

Peroxisome proliferator-activated receptor (PPAR α/γ) agonists as a potential target to reduce cardiovascular risk in diabetes

The disappointing results of glucose lowering studies have highlighted the ongoing need to develop new therapeutic strategies to reduce cardiovascular risk in patients with type 2 diabetes. The presence of a range of metabolic abnormalities in diabetic patients presents a number of potential targets for therapeutic intervention. While modulation of peroxisome proliferator activated receptors (PPARs) represents an attractive approach, the results of studies of pharmacological agonists have been variable. The findings of these studies and rationale for development of dual PPAR-α/γ agonists will be reviewed.

Up-regulation of peroxisome proliferator-activated receptor gamma in radiation-induced heart injury in rats

To explore the expression level and the role of peroxisome proliferator-activated receptor gamma (PPAR-γ) in radiation-induced heart injury in a rat model, thirty-two Sprague-Dawley rats were divided into three groups (the control group, the 15-Gy irradiation group and the 18-Gy irradiation group). Experimental animals were exposed to radiation generated by a linear accelerator at the chest and killed after 3 months. Heart tissues from these animals were removed for Masson staining, PPAR-γ immunohistochemical staining, Western blot analysis and real-time polymerase chain reaction assay (RT-PCR). In addition, the protein expression of matrix metalloprotein-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and transforming growth factor type beta1 (TGF-β1), all of which are associated with fibrosis, was measured. Masson staining revealed significant myocardial fibrosis, degeneration and necrosis in rats exposed to radiation. The results of immunohistochemical staining and Western blot analysis showed that PPAR-γ protein expression in hearts of the irradiation groups was significantly higher than in the control group, especially in myocardium and vascular endothelial (p < 0.05). RT-PCR results also showed a parallel increase in PPAR-γ mRNA expression in the heart of the irradiation groups compared with the control group (p < 0.05). The expression of MMP-1 protein was not significantly different in three groups (p > 0.05). The expression of TIMP-1 and TGF-β1 proteins was, however, higher in two irradiation groups than in the control group (p < 0.05). These data demonstrate that PPAR-γ expression is up-regulated on both mRNA and protein levels in heart injured by radiation. PPAR-γ may play an important role in radiation-induced heart injury.

Matrix metalloproteinase inhibition therapy for vascular diseases

The matrix metalloproteinases (MMPs) are 23 secreted or cell surface proteases that act together and with other protease classes to turn over the extracellular matrix, cleave cell surface proteins and alter the function of many secreted bioactive molecules. In the vasculature MMPs influence the migration proliferation and apoptosis of vascular smooth muscle, endothelial cells and inflammatory cells, thereby affecting intima formation, atherosclerosis and aneurysms, as substantiated in clinical and mouse knockout and transgenic studies. Prominent counterbalancing roles for MMPs in tissue destruction and repair emerge from these experiments. Naturally occurring tissue inhibitors of MMPs (TIMPs), pleiotropic mediators such as tetracyclines, chemically-synthesised small molecular weight MMP inhibitors (MMPis) and inhibitory antibodies have all shown effects in animal models of vascular disease but only doxycycline has been evaluated extensively in patients. A limitation of broad specificity MMPis is that they prevent both matrix degradation and tissue repair functions of different MMPs. Hence MMPis with more restricted specificity have been developed and recent studies in models of atherosclerosis accurately replicate the phenotypes of the corresponding gene knockouts. This review documents the established actions of MMPs and their inhibitors in vascular pathologies and considers the prospects for translating these findings into new treatments.

Mice with cardiac overexpression of peroxisome proliferator-activated receptor γ have impaired repolarization and spontaneous fatal ventricular arrhythmias

BACKGROUND

Diabetes mellitus and obesity, which confer an increased risk of sudden cardiac death, are associated with cardiomyocyte lipid accumulation and altered cardiac electric properties, manifested by prolongation of the QRS duration and QT interval. It is difficult to distinguish the contribution of cardiomyocyte lipid accumulation from the contribution of global metabolic defects to the increased incidence of sudden death and electric abnormalities.

METHODS AND RESULTS

In order to study the effects of metabolic abnormalities on arrhythmias without the complex systemic effects of diabetes mellitus and obesity, we studied transgenic mice with cardiac-specific overexpression of peroxisome proliferator-activated receptor γ 1 (PPARγ1) via the cardiac α-myosin heavy-chain promoter. The PPARγ transgenic mice develop abnormal accumulation of intracellular lipids and die as young adults before any significant reduction in systolic function. Using implantable ECG telemeters, we found that these mice have prolongation of the QRS and QT intervals and spontaneous ventricular arrhythmias, including polymorphic ventricular tachycardia and ventricular fibrillation. Isolated cardiomyocytes demonstrated prolonged action potential duration caused by reduced expression and function of the potassium channels responsible for repolarization. Short-term exposure to pioglitazone, a PPARγ agonist, had no effect on mortality or rhythm in WT mice but further exacerbated the arrhythmic phenotype and increased the mortality in the PPARγ transgenic mice.

CONCLUSIONS

Our findings support an important link between PPARγ activation, cardiomyocyte lipid accumulation, ion channel remodeling, and increased cardiac mortality.

Changes in the activity of connective tissue matrix enzymes in the metabolic syndrome

INTRODUCTION

Early atherosclerotic changes in the endothelium associated with metabolic syndrome are generated with the participation of inflammatory cells, cytokines and enzymes of the extracellular matrix. The study is aimed at a comparison between the activity of inflammatory agents, tumour necrosis factor α (TNF-α) and the enzymes of the connective tissue matrix in the blood of healthy female patients as well as those suffering from the metabolic syndrome.

MATERIAL AND METHODS

The examination included 35 women with metabolic syndrome (MS). The control group (C) comprised 35 healthy women. Lipidogram, C-reactive protein level (CRP), fasting glucose level (FGL), matrix metalloproteinase (MMP)-8 and -9 activity, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TNF-α levels in blood were determined.

RESULTS

As compared with the control group, the level of inflammatory factors and the activity of extracellular matrix enzymes in the metabolic syndrome were statistically higher (p < 0.05) and concerned the following parameters: TNF-α (pg/ml): MS 6.59 ±3.18, C 4.78 ±2.91; CRP (mg/dl): MS 2.18 ±2.04, C 1,26 ±1.35; TIMP-1 (ng/ml): MS 265.5 ±2.9, C 205.4 ±72.6; MMP-9 (ng/ml): MS 198.2 ±138.6, C 138.6 ±116.1. Statistically significant correlations were also found between TIMP-1 and the following factors: BMI (R = 0.400, p < 0.001), waist/hip ratio (WHR) (R = 0.278, p < 0.05), waistline (R = 0.417, p < 0.001), FGL (R = 0.290, p < 0.05), HDL cholesterol (R = -0.253, p < 0.05) and triglycerides (R = 0.269, p < 0.05).There were positive correlations of MMP-9 with FGL (R = 0.446, p < 0.001) and waistline (R = 0.260, p < 0.05); MMP-8 with FGL (R = 0.308, p < 0.05); and CRP with BMI (R = 0.370, p < 0.01), WHR (R = 0.325, p < 0.01) and waistline (R = 0.368, p < 0.01).

CONCLUSIONS

Metabolic syndrome is connected with higher activity of cytokines (TNF-α), inflammatory markers (CRP) and matrix enzymes (MMP-9, MMP-8, TIMP-1).

Peroxisome proliferator-activated receptor and age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of new blindness in the western world and is becoming more of a socio-medical problem as the proportion of the aged population increases. There are multiple efforts underway to better understand this disease process. AMD involves the abnormal retinal pigment epithelium (RPE), drusen formation, photoreceptor atrophy, and choroidal neovascularization. Peroxisome proliferator-activated receptors (PPARs) play an important role in lipid degeneration, immune regulation, regulation of reactive oxygen species (ROSs), as well as regulation of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9), and docosahexaenoic acid (DHA). These molecules have all been implicated in the pathogenesis of AMD. In addition, PPAR gamma is expressed in RPE, an essential cell in photoreceptor regeneration and vision maintenance. This review summarizes the interactions between PPAR, AMD-related molecules, and AMD-related disease processes.

Adiponectin is required for PPARγ-mediated improvement of endothelial function in diabetic mice

Rosiglitazone is a PPARγ agonist commonly used to treat diabetes. In addition to improving insulin sensitivity, rosiglitazone restores normal vascular function by a mechanism that remains poorly understood. Here we show that adiponectin is required to mediate the PPARγ effect on vascular endothelium of diabetic mice. In db/db and diet-induced obese mice, PPARγ activation by rosiglitazone restores endothelium-dependent relaxation of aortae, whereas diabetic mice lacking adiponectin or treated with an anti-adiponectin antibody do not respond. Rosiglitazone stimulates adiponectin release from fat explants, and subcutaneous fat transplantation from rosiglitazone-treated mice recapitulates vasodilatation in untreated db/db recipients. Mechanistically, adiponectin activates AMPK/eNOS and cAMP/PKA signaling pathways in aortae, which increase NO bioavailability and reduce oxidative stress. Taken together, these results demonstrate that adipocyte-derived adiponectin is required for PPARγ-mediated improvement of endothelial function in diabetes. Thus, the adipose tissue represents a promising target for treating diabetic vasculopathy.

Telmisartan, a unique ARB, improves left ventricular remodeling of infarcted heart by activating PPAR gamma

Unfavorable left ventricular (LV) remodeling after myocardial infarction (MI) leads to cardiac dysfunction. We examined whether Telmisartan, an angiotensin (Ang) II type I receptor blocker (ARB), could improve the recovery of LV function in a rat model of MI. The effect of Telmisartan as a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist was also investigated. After 28 days of MI, a significant improvement of survival was observed in the Telmisartan-treated rat group compared with the vehicle control rat group, non-PPAR-γ agonistic ARB (Losartan)-treated rat group, and Telmisartan plus specific PPAR-γ antagonist (GW9662)-treated rat group. Although no significant differences of blood pressure or infarct size were observed among these four groups, the Telmisartan group had better systolic and diastolic LV function. There was a significant reduction of the plasma brain natriuretic peptide level, cardiac fibrosis area, infiltration of macrophages, size of cardiomyocytes, terminal deoxynucleotidyl transferase dUTP nick end labeling-positive myocytes, activation of matrix metalloproteinases-2 and -9 (MMPs-2/9), and expression of transforming growth factor β-1 (TGF-β1), connective tissue growth factor (CTGF), and osteopontin (OPN), while expression of PPAR-γ and activation of tissue inhibitor of metalloproteinase-1 (TIMP-1) was enhanced, in the noninfarcted myocardium of rats from the Telmisartan group compared with the other three groups. To mimic ischemic conditions in vitro, neonatal rat cardiomyocytes and cardiac fibroblasts were incubated in hypoxic condition for 24 h. Increased transcriptional activation of PPAR-γ and TIMP-1, and inhibition of TGF-β1 expression were observed in cardiomyocytes, while decreased activation of MMPs-2/9 and decrease in CTGF and OPN expression was seen in cardiac fibroblasts cultured with Telmisartan. In conclusion, Telmisartan prevented unfavorable cardiac remodeling through a reduction of cardiac hypertrophy and fibrosis. An anti-inflammatory effect and PPAR-γ activation were suggested to be important in addition to suppression of Ang II activity.

[Effects of Chinese herbal medicine Jinqi Jiangtang Tablet on serum matrix metalloproteinase-9 level and its expression in peripheral blood monocytes of rats with diabetes mellitus]

OBJECTIVE

To observe the effects of Jinqi Jiangtang Tablet, a compound Chinese herbal medicine, on serum matrix metalloproteinase-9 (MMP-9) level and MMP-9 expression in peripheral blood monocytes of rats with streptozocin-induced diabetes.

METHODS

Thirty Wistar rats were randomly divided into 3 groups: control group, untreated group and Jinqi Jiangtang Tablet group. Diabetes in rats was induced by a single intraperitoneal injection of streptozocin (70mg/kg body weight). After model building, rats in the Jinqi Jiangtang Tablet group were administered with Jinqi Jiangtang tablets at a dose of 0.8 g/(kg·d) for 6 weeks and rats in the control group and the untreated group were treated with normal saline. After treatment, level of fasting serum glucose was detected by hexokinas method; serum MMP-9 level was tested by enzyme-linked immunosorbent assay; MMP-9 expression in peripheral blood monocytes was measured by reverse transcription-polymerase chain reaction and Western blot method.

RESULTS

After treatment, fasting serum glucose level in the Jinqi Jiangtang Tablet group was less than that in the untreated group (P<0.05). After modeling, the serum MMP-9 level of rats in the untreated group was (9.11±3.55) μg/L and that in Jinqi Jiangtang Tablet group was (8.97± 3.07) μg/L, which were higher than that in the control group ((4.39±1.44) μg/L) (P<0.01). After gavage, the level of serum MMP-9 was lower in Jinqi Jiangtang Tablet group than in the untreated group (P<0.05). The expression of MMP-9 in peripheral blood monocytes in the untreated group was higher than that in the control group (P<0.05). The MMP-9 expression in peripheral blood monocytes of rats with diabetes was down-regulated by Jinqi Jiangtang Tablet (P<0.05).

CONCLUSION

Jinqi Jiangtang Tablet can decrease the level of serum MMP-9 and down-regulate the MMP-9 expression in peripheral blood monocytes at both mRNA and protein levels in rats with diabetes.