Anti-fibrotic effect of ciglitazone in HRV-induced airway remodelling cell model.

Fibrosis is an important phenomenon as it can occur early in the pathogenesis of asthma; it may be associated with disease severity and resistance to therapy. There is a strong evidence that infection caused by human rhinovirus (HRV) contributes to remodelling process, but there is lack of studies clearly explaining this pathway. Synthetic peroxisome proliferator-activated receptor (PPAR) γ presents immunomodulatory and anti-inflammatory features. In this study, we examined immunomodulatory properties of ciglitazone - PPAR-γ agonist, in development and modulation of airway remodelling. Epithelial cells (NHBE) and two lines of fibroblasts (WI-38, HFL1) were stimulated with ciglitazone and rhinovirus. The expression of genes related to airway remodelling process were analysed in the cells; moreover NF-κB, c-Myc and STAT3 were silenced in order to estimate potential pathways involved. Ciglitazone decreased mRNA expression of MMP-9 and TGF-ß. It also modified the expression of α-SMA and collagen after rhinovirus infection. Transcription factors knockdown altered the levels of expression. The results suggest possible anti-fibrotic activity of PPAR-γ agonist in human airway cells. Ciglitazone has been shown to be dependent on NF-κB- and STAT3-related pathways, thus, the PPAR-γ agonist may have therapeutic potential for the treatment of airway remodelling in asthma.

Utilizing systems biology to reveal cellular responses to peroxisome proliferator-activated receptor γ ligand exposure.

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that, upon activation by ligands, heterodimerizes with retinoid X receptor (RXR), binds to PPAR response elements (PPREs), and activates transcription of downstream genes. As PPARγ plays a central role in adipogenesis, fatty acid storage, and glucose metabolism, PPARγ-specific pharmaceuticals (e.g., thiazolidinediones) have been developed to treat Type II diabetes and obesity within human populations. However, to our knowledge, no prior studies have concurrently assessed the effects of PPARγ ligand exposure on genome-wide PPARγ binding as well as effects on the transcriptome and lipidome within human cells at biologically active, non-cytotoxic concentrations. In addition to quantifying concentration-dependent effects of ciglitazone (a reference PPARγ agonist) and GW 9662 (a reference PPARγ antagonist) on human hepatocarcinoma (HepG2) cell viability, PPARγ abundance in situ, and neutral lipids, HepG2 cells were exposed to either vehicle (0.1% DMSO), ciglitazone, or GW 9662 for up to 24 h, and then harvested for 1) chromatin immunoprecipitation-sequencing (ChIP-seq) to identify PPARγ-bound regions across the entire genome, 2) mRNA-sequencing (mRNA-seq) to identify potential impacts on the transcriptome, and 3) lipidomics to identify potential alterations in lipid profiles. Following exposure to ciglitazone and GW 9662, we found that PPARγ levels were not significantly different after 2-8 h of exposure. While ciglitazone and GW 9662 resulted in a concentration-dependent increase in neutral lipids, the magnitude and localization of PPARγ-bound regions across the genome (as identified by ChIP-seq) did not vary by treatment. However, mRNA-seq and lipidomics revealed that exposure of HepG2 cells to ciglitazone and GW 9662 resulted in significant, treatment-specific effects on the transcriptome and lipidome. Overall, our findings suggest that exposure of human cells to PPARγ ligands at biologically active, non-cytotoxic concentrations results in toxicity that may be driven by a combination of both PPARγ-dependent and PPARγ-independent mechanisms.

Effect of ciglitazone on adipogenic transdifferentiation of bovine skeletal muscle satellite cells.

Ciglitazone is a member of the thiazolidinedione family, and specifically binds to peroxisome proliferator-activated receptor-γ (PPARγ), thereby promoting adipocyte differentiation. We hypothesized that ciglitazone as a PPARγ ligand in the absence of an adipocyte differentiation cocktail would increase adiponectin and adipogenic gene expression in bovine satellite cells (BSC). Muscle-derived BSCs were isolated from six, 18-month-old Yanbian Yellow Cattle. The BSC were cultured for 96 h in differentiation medium containing 5 µM ciglitazone (CL), 10 µM ciglitazone (CM), or 20 µM ciglitazone (CH). Control (CON) BSC were cultured only in a differentiation medium (containing 2% horse serum). The presence of myogenin, desmin, and paired box 7 (Pax7) proteins was confirmed in the BSC by immunofluorescence staining. The CL, CM, and CH treatments produced higher concentrations of triacylglycerol and lipid droplet accumulation in myotubes than those of the CON treatment. Ciglitazone treatments significantly increased the relative expression of PPARγ, CCAAT/enhancer-binding protein alpha (C/EBPα), C/EBPß, fatty acid synthase, stearoyl-CoA desaturase, and perilipin 2. Ciglitazone treatments increased gene expression of Pax3 and Pax7 and decreased expression of myogenic differentiation-1, myogenin, myogenic regulatory factor-5, and myogenin-4 (p < 0.01). Adiponectin concentration caused by ciglitazone treatments was significantly greater than CON (p < 0.01). RNA sequencing showed that 281 differentially expressed genes (DEGs) were found in the treatments of ciglitazone. DEGs gene ontology (GO) analysis showed that the top 10 GO enrichment significantly changed the biological processes such as protein trimerization, negative regulation of cell proliferation, adipocytes differentiation, and cellular response to external stimulus. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that DEGs were involved in the p53 signaling pathway, PPAR signaling pathway, biosynthesis of amino acids, tumor necrosis factor signaling pathway, non-alcoholic fatty liver disease, PI3K-Akt signaling pathway, and Wnt signaling pathway. These results indicate that ciglitazone acts as PPARγ agonist, effectively increases the adiponectin concentration and adipogenic gene expression, and stimulates the conversion of BSC to adipocyte-like cells in the absence of adipocyte differentiation cocktail.

Retinoids Augment Thiazolidinedione PPARγ Activation in Oral Cancer Cells.

BACKGROUND/AIM: Head and neck squamous cell carcinoma affects nearly 500,000 people annually. Augmenting PPARγ functional activation is linked with multiple anti-carcinogenic processes in aerodigestive cell lines and animal models. PPARγ/RXRα heterodimers may be key partners in this activation. MATERIALS AND METHODS: CA 9-22 and NA cell lines were treated with the PPARγ agonist ciglitazone and/or the RXRα agonist 9-cis-retinoic acid. PPARγ functional activation, cellular proliferation, apoptosis activity, and phenotype were subsequently analyzed. RESULTS: Ciglitazone and 9-cis-retinoic acid independently activated PPARγ and down-regulated the carcinogenic phenotype in vitro. Combination treatment significantly augmented these effects, further decreasing proliferation (p<0.0001), and increasing PPARγ functional activation (p<0.0001), apoptosis (p<0.05), and adipocyte differentiation markers (p<0.0001). CONCLUSION: The efficacy of the combination of ciglitazone and 9-cis-retinoic acid afforded lowering treatment concentrations while maintaining desired therapeutic outcomes, optimistically supporting the feasibility and practicality of this novel treatment option.

Effects of PPAR-γ agonists on oral cancer cell lines: Potential horizons for chemopreventives and adjunctive therapies.

BACKGROUND: Peroxisome proliferator-activated receptor-gamma (PPAR-γ) activators have anti-cancer effects. Our objective was to determine the effect of PPAR-γ ligands 15-deoxy-D12,14 -Prostaglandin J2 (15-PGJ2 ) and ciglitazone on proliferation, apoptosis, and NF-κB in human oral squamous cell carcinoma cell lines. METHODS: NA and CA9-22 cells were treated in vitro with 15-PGJ2 and ciglitazone. Proliferation was measured by MTT colorimetric assay and cell cycle analysis performed via flow cytometry, apoptosis by caspase-3 colorimetric assay and poly-(ADP-ribose) polymerase cleavage on Western blot, and NF-κB activation by luciferase assays. RESULTS: MTT assays demonstrated dose-dependent decreases after 15-PGJ2 treatment in both cell lines, and S-phase cell cycle arrest was also demonstrated. NF-κB luciferase reporter gene activity decreased seven- and eightfold in NA and CA9-22 cells, respectively. Caspase-3 activity increased two- and eightfold in NA and CA9-22 cells, respectively. CONCLUSIONS: Our results suggest these agents, in addition to activating PPAR-γ, can downregulate NF-κB and potentiate apoptosis in oral cancer cells.

Ciglitazone-a human PPARγ agonist-disrupts dorsoventral patterning in zebrafish.

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor that regulates lipid/glucose homeostasis and adipocyte differentiation. While the role of PPARγ in adipogenesis and diabetes has been extensively studied, little is known about PPARγ function during early embryonic development. Within zebrafish, maternally-loaded pparγ transcripts are present within the first 6 h post-fertilization (hpf), and de novo transcription of zygotic pparγ commences at ~48 hpf. Since maternal pparγ transcripts are elevated during a critical window of cell fate specification, the objective of this study was to test the hypothesis that PPARγ regulates gastrulation and dorsoventral patterning during zebrafish embryogenesis. To accomplish this objective, we relied on (1) ciglitazone as a potent PPARγ agonist and (2) a splice-blocking, pparγ-specific morpholino to knockdown pparγ. We found that initiation of ciglitazone-a potent human PPARγ agonist-exposure by 4 hpf resulted in concentration-dependent effects on dorsoventral patterning in the absence of epiboly defects during gastrulation, leading to ventralized embryos by 24 hpf. Interestingly, ciglitazone-induced ventralization was reversed by co-exposure with dorsomorphin, a bone morphogenetic protein signaling inhibitor that induces strong dorsalization within zebrafish embryos. Moreover, mRNA-sequencing revealed that lipid- and cholesterol-related processes were affected by exposure to ciglitazone. However, pparγ knockdown did not block ciglitazone-induced ventralization, suggesting that PPARγ is not required for dorsoventral patterning nor involved in ciglitazone-induced toxicity within zebrafish embryos. Our findings point to a novel, PPARγ-independent mechanism of action and phenotype following ciglitazone exposure during early embryonic development.

Oleic acid in the absence of a PPARγ agonist increases adipogenic gene expression in bovine muscle satellite cells1.

We hypothesized that oleic acid (OA) in the absence of a thiazolidinedione (i.e., a synthetic peroxisome proliferator-activated receptorγ [PPARγ] agonist) would increase adipogenic gene expression in bovine muscle satellite cells (BSC). The BSC were cultured in differentiation medium containing 10 µM ciglitazone (CI), 100 µM OA, or 100 µM OA plus 10 µM CI (CI-OA). Control (CON) BSC were cultured only in differentiation media (containing 2% horse serum). The presence of myogenin, desmin, and paired box 7 proteins was confirmed in the BSC by immunofluorescence staining, demonstrating that we had isolated myogenic cells. The OA BSC had lesser paired box 3 (Pax3) and myogenic differentiation 1 expression but greater Pax7 and mygogenin (MYOG) expression (P < 0.05), than the CON BSC. The CI BSC had greater Pax3, Pax7, and MYOG expression than CON BSC (P < 0.05), suggesting that CI would promote BSC myogenesis under pro-myogenic conditions (i.e., when cultured with horse serum). However, both the OA and CI treatments upregulated the expression of PPARγ, CCAAT/enhancer-binding protein alpha (C/EBPα) and C/EBPß, sterol regulatory element-binding protein 1, lipoprotein lipase, and glycerol-3-phosphate acyltransferase 3 gene expression, as well as media adiponectin concentration (P < 0.05). The CI, OA, and CI-OA treatments also increased triacylglycerol and lipid droplet accumulation, in spite of upregulation (relative to CON BSC) of adenosine monophosphate-activated protein kinase alpha-1, perilipin 2 (PLIN2), and PLIN3 in BSC and downregulation of G protein-coupled protein receptor 43, acyl-CoA synthetase long chain family member 3, and stearoyl-CoA desaturase (P < 0.05). These results indicate that OA in the absence of a synthetic PPARγ agonist can effectively increase adipogenic gene expression in BSC.

Overexpression of tensin homolog deleted on chromosome ten (PTEN) by ciglitazone sensitizes doxorubicin-resistance leukemia cancer cells to treatment.

Overcoming multidrug resistance (MDR) is a final goal of various recent studies, in which combination of different compounds and conventional chemotherapeutics results in circumventing MDR and hence cancer progression. Therefore, we aimed to investigate the effects of peroxisome proliferator-activated receptors (PPARs)-γ on MDR in doxorubicin-resistant human myelogenous leukemia cells. The effect of doxorubicin on cell viability following treatment with ciglitazone was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The activity of P-glycoprotein (P-gp), as one of the membrane transporters, was determined by the rhodamine 123 (Rho 123) assay. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot were used for the measurement of P-gp, and tensin homolog deleted on chromosome ten (PTEN) expression at mRNA and protein, respectively. For evaluation of doxorubicin (DOX)-induced apoptosis by annexin V/PI staining was used. Ciglitazone significantly increases the cytotoxic effects of DOX. In addition, ciglitazone considerably decreased the expression levels and activity of P-gp in DOX-resistant K562 cells. Furthermore, upon the ciglitazone treatment, PTEN expression could be increased in K562/DOX cells in a PPARγ-dependent manner. Moreover, ciglitazone significantly enhanced DOX-induced apoptosis in K562/DOX cells. The combination treatment of K562/DOX leukemia cancer cells with doxorubicin and ciglitazone might be an effective strategy in inducing apoptosis and reversing developed MDR, and more importantly decreasing the adverse side effects of these agents.

Crosstalk between PPARγ Ligands and Inflammatory-Related Pathways in Natural T-Regulatory Cells from Type 1 Diabetes Mouse Model.

Immunomodulation, as a means of immunotherapy, has been studied in major research and clinical laboratories for many years. T-Regulatory (Treg) cell therapy is one of the modulators used in immunotherapy approaches. Similarly, nuclear receptor peroxisome proliferator activated receptor gamma (PPARγ) has extensively been shown to play a role as an immuno-modulator during inflammation. Given their mutual roles in downregulating the immune response, current study examined the influence of PPARγ ligands i.e., thiazolidinedione (TZD) class of drugs on Forkhead Box P3 (Foxp3) expression and possible crosstalk between PPARγ and nTreg cells of Non-Obese Diabetes (NOD) and Non-Obese Diabetes Resistant (NOR) mice. Results showed that TZD drug, ciglitazone and natural ligand of PPARγ 15d-prostaglandin downregulated Foxp3 expression in activated nTreg cells from both NOD and NOR mice. Interestingly, addition of the PPARγ inhibitor, GW9662 further downregulated Foxp3 expression in these cells from both mice. We also found that PPARγ ligands negatively regulate Foxp3 expression in activated nTreg cells via PPARγ-independent mechanism(s). These results demonstrate that both natural and synthetic PPARγ ligands capable of suppressing Foxp3 expression in activated nTreg cells of NOD and NOR mice. This may suggest that the effect of PPARγ ligands in modulating Foxp3 expression in activated nTreg cells is different from their reported effects on effector T cells. Given the capability to suppress Foxp3 gene, it is possible to be tested as immunomodulators in cancer-related studies. The co-lateral use of PPARγ ligands in nTreg cells in inducing tolerance towards pseudo-self antigens as in tumor microenvironment may uphold beneficial outcomes.

Inhibition of ERK activity enhances the cytotoxic effect of peroxisome proliferator-activated receptor γ (PPARγ) agonists in HeLa cells.

In this study, we examined whether the peroxisome proliferator-activated receptor γ (PPARγ) agonists, ciglitazone (CGZ) and troglitazone (TGZ), induce cell death in human cervical cancer HeLa cells. The cells were treated with a range of CGZ or TGZ doses for 24 or 48 h. Low concentrations of CGZ (≤10 µM) or TGZ (≤20 µM) had no effect on cell viability whereas higher doses induced cell death in a time- and dose-dependent manner as evidenced by the detection of activated caspase-3 and PARP cleavage. Treatment with the PPARγ antagonist GW9662 followed by PPARγ agonists did not increase CGZ- or TGZ-induced cell death, indicating that PPARγ agonists induced HeLa cell death independently of PPARγ. Moreover, ERK1/2 activation was observed at a CGZ concentration of 25 µM and a TGZ concentration of 35 µM, both of which induced cell death. To elucidate the role of ERK1/2 activated by the two PPARγ agonists, the effect of U0126, an inhibitor of ERK1/2, on PPARγ-agonist-induced cell death was examined. Treatment with 10 or 20 µM U0126 followed by CGZ or TGZ induced the down-regulation of ERK1/2 activity and a decrease in Bcl-2 expression accompanied by the collapse of mitochondrial membrane potential, which in turn significantly enhanced CGZ- or TGZ-induced apoptotic cell death. Our results suggest that PPARγ agonists are capable of inducing apoptotic cell death in HeLa cells independently of PPARγ and that inhibition of ERK1/2 activity offers a strategy to enhance the cytotoxicity of PPARγ agonists in the treatment of cervical cancer.

A novel polymer-free ciglitazone-coated vascular stent: in vivo and ex vivo analysis of stent endothelialization in a rabbit iliac artery model.

AIM: Peroxisome proliferator-activated receptor-gamma (PPARg) agonists have known pleiotropic cardiovascular effects with favourable properties in vascular remodeling, and specifically in suppression of vascular smooth muscle cell proliferation. A novel vascular stent coating using the PPARg ligand ciglitazone (CCS) was investigated regarding its effects on endothelialization after 7 and 28 days. METHODS: Microporous bare metal stents (BMS) were coated with ciglitazone by ultrasonic flux with a load of 255 µg ciglitazone/stent. SixteenNew Zealand white rabbits, fed a with high cholesterol diet, underwent stent implantation in both iliac arteries. Everolimus-eluting stents (EES) and BMS were comparators. Histology (CD 31 immunostaining, confocal and scanning electron microscopy, morphometry) was performed after 7 and 28 days and by OCT (optical coherence tomography) in vivo after 28 days. RESULTS: Microscopy showed comparable results with near complete endothelialization in CCS and BMS (%CD31 above stent struts after 7 days: 67.92±36.35 vs. 84.48±23.86; p = 0.55; endothel % above stent struts: 77.22±27.9 vs. 83.89±27.91; p = 0.78). EES were less endothelialized with minimal fibrin deposition, not found in BMS and CCS (% CD 31 above struts after 28 days, BMS: 100.0±0.0 vs. EES: 95.9±3.57 vs. CCS: 100.0±0.0; p = 0.0292). OCT revealed no uncovered struts in all stents after 28 days. CONCLUSIONS: Polymer-free coating with ciglitazone, a PPARg agonist is feasible and stable over time. Our data prove unimpaired endothelial coverage of a ciglitazone-coated vascular stent system by histology and OCT. Thus, this PPARg agonist coating deserves further investigation to evaluate its potency on local neointimal suppression.

Peroxisome proliferator-activated receptors (PPARs) and PPAR agonists: the 'future' in dermatology therapeutics?

Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors and comprise three different isoforms namely PPARα, PPARγ, and PPARß/δ with PPARß/δ being the predominant subtype in human keratinocytes. After binding with specific ligands, PPARs regulate gene expression, cell growth and differentiation, apoptosis, inflammatory responses, and tumorogenesis. PPARs also modulate a wide variety of skin functions including keratinocyte proliferation, epidermal barrier formation, wound healing, melanocyte proliferation, and sebum production. Recent studies have shown the importance of PPARs in the pathogenesis of many dermatological disorders. Clinical trials have suggested possible role of PPAR agonists in the management of various dermatoses ranging from acne vulgaris, psoriasis, hirsutism, and lipodystrophy to cutaneous malignancies including melanoma. This article is intended to be a primer for dermatologists in their understanding of clinical relevance of PPARs and PPAR agonists in dermatology therapeutics.

Ciglitazone enhances ovarian cancer cell death via inhibition of glucose transporter-1.

Ciglitazone is a peroxisome proliferator-activated receptor γ (PPARγ) agonist and improves insulin sensitivity. Apart from antidiabetic activity, ciglitazone elicits inhibitory effects on cancer cell growth. Recent studies indicate that glucose metabolism plays a key role in malignant diseases. Significant increase in glucose consumption is found under malignant conditions. The role of ciglitazone in cancer cell death in relation to glucose metabolism is unclear. Thus we designed this study to determine the effect of ciglitazone on glucose metabolism. First, we found ciglitazone inhibited glucose uptake in ovarian cancer cells but did not affect hexokinase activity. Ciglitazone decreased expression levels of glucose transporter-1 (GLUT-1). We also found that ciglitazone and siGLUT-1 treatments induced cell death in ovarian cancer cells. We identified that ciglitazone decreased expressions of specific protein 1 (Sp-1) and ß-catenin while increased phosphorylation levels of AMP-activated protein kinase. In vivo study using NOD-scid IL2Rgamma(null) mice confirmed that ciglitazone significantly decreased ovarian cancer mass transplanted onto the back of the mice. Finally, we determined GLUT-1 expressions in patients with serous type ovarian cancer and found that GLUT-1 expression was markedly increased in cancer patients and expression level was proportional to the degree of cancer stages. These results suggest that ciglitazone induces apoptosis in ovarian cancer cells by the inhibition of GLUT-1 and provides a possible therapeutic effect of ciglitazone as an adjuvant drug in the treatment of ovarian cancer.

Activation of peroxisome proliferator activated receptor-gamma results in an atheroprotective apolipoprotein profile in HepG2 cells.

BACKGROUND: Insulin resistance is linked to dyslipidemia, characterized by a decrease in high density lipoproteins and an increase in low density lipoproteins. Thiazolidinediones (TZDs) are insulin-sensitizing agents used to improve glycemic control in patients with type 2 diabetes. Recently, the safety of certain TZD regimens has been questioned because of associated adverse effects on the plasma lipid profile. We examined the effect of a TZD, Ciglitazone, on apolipoprotein synthesis and secretion in human liver HepG2 cells. METHODS AND RESULTS: The effect of Ciglitazone treatment on apolipoprotein synthesis was addressed at the level of transcription, translation and secretion. RT-PCR showed that Ciglitazone increased the transcription of apoE and apoAI but reduced the levels of apoCI and apoB mRNA. Western blot analysis showed an increase in apoAI and apoE secreted in the cell culture media, whereas the amounts of apoB100 and apoCI were reduced. To confirm that Ciglitazone regulates apolipoprotein translation, its effect on de novo protein synthesis was evaluated by metabolic labeling with [35S]-methionine/cysteine, and a similar pattern of regulation was observed. The change in apolipoprotein levels was not secondary to cholesterol biosynthesis or clearance, since Ciglitazone did not regulate the transcription of HMGCoA reductase, or the LDL receptor. However, mRNA levels for both PPAR-γ and LXRα were induced, suggesting a role for either or both receptors in modulating the hepatic apolipoprotein profile. The involvement of these nuclear receptor transcription factors was confirmed since direct activation of these receptors by endogenous PPAR-γ ligand, 15d-prostaglandin J2, or LXRα ligand, 22(R)hydroxycholesterol, similarly upregulated apoAI and apoE, but down-regulated apoB100 protein synthesis. CONCLUSION: Our results suggest that Ciglitazone treatment results in an atheroprotective lipoprotein profile in liver cells. Thus, while the adipose and muscle tissues may be primary targets in TZD-mediated glucose homeostasis, liver PPAR-γ contributes significantly to the regulation of plasma lipoprotein profile.

Ciglitazone, a novel inhibitor of lung apoptosis following hemorrhagic shock.

Apoptosis or programmed cell death has been demonstrated to play a role in the development of lung injury following hemorrhagic shock. A major pathway modulating the apoptotic response is the phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K/Akt) pathway. Ciglitazone, a peroxisome proliferator-activated receptor-y (PPARy) ligand has previously been shown to attenuate lung inflammation following hemorrhagic shock. In vivo similar ligands have demonstrated anti-apoptotic effects with a reduction in organ injury in models of acute illness. In this study we examined the effect of ciglitazone on apoptosis and PI3K/Akt signaling in the lung following severe hemorrhage and resuscitation. Hemorrhagic shock was induced in male Wistar rats by withdrawing blood from the femoral artery to a mean arterial pressure of 50 mmHg. Animals were kept in shock for 3h at which time they were rapidly resuscitated by returning their shed blood. At the time of resuscitation and every hour thereafter, groups of animals received ciglitazone (10mg/kg) or DMSO intraperitoneally. Vehicle-treated rats had increased lung apoptosis following hemorrhage and resuscitation by Tunel staining. This was associated with increased activity of caspase-3. Ciglitazone treatment reduced lung apoptosis with a significant reduction in caspase-3 activity. This was associated with increased phosphorylation of the pro-survival kinase Akt. Thus, our data suggest that ciglitazone, a PPARy ligand, promotes cell survival in the lung following hemorrhagic shock.

PPAR gamma agonist normalizes glomerular filtration rate, tissue levels of homocysteine, and attenuates endothelial-myocyte uncoupling in alloxan induced diabetic mice.

BACKGROUND: Homocysteine (Hcy) is an independent cardiovascular risk factor; however, in diabetes, the role of tissue Hcy leading to cardiac dysfunction is unclear. AIMS: To determine whether tissue Hcy caused endothelial-myocyte uncoupling and ventricular dysfunction in diabetes. METHODS: Diabetes was created in C57BL/6J male mice by injecting 65 mg/kg alloxan. To reverse diabetic complications, ciglitazone (CZ) was administered in the drinking water. Plasma glucose, Hcy, left ventricular (LV) tissue levels of Hcy and nitric oxide (NO) were measured. Glomerular filtration rate (GFR) was measured by inulin-FITC. Endothelial-myocyte coupling was measured in cardiac rings. In vivo diastolic relaxation and LV diameters were measured by a Millar catheter in LV and by M-mode echocardiography, respectively. RESULTS: Plasma glucose, GFR and LV tissue Hcy were increased in diabetic mice and were normalized after CZ treatment; whereas, elevated plasma Hcy level remained unchanged with or without CZ treatment. NO levels in the LV were found inversely related to tissue Hcy levels. Attenuated endothelial-myocyte function in diabetic mice was ameliorated by CZ treatment. Cardiac relaxation, the ratio of LV wall thickness to LV diameter was decreased in diabetes, and normalized after CZ treatment. CONCLUSION: CZ normalized LV tissue levels of Hcy and ameliorated endothelial-myocyte coupling; therefore, specifically suggest the association of LV tissue Hcy levels with impair endothelial-myocyte function in diabetes.