Pioglitazone Induces Cardiomyocyte Apoptosis and Inhibits Cardiomyocyte Hypertrophy Via VEGFR-2 Signaling Pathway / Pioglitazona Induz Apoptose e Inibe Hipertrofia de Cardiomiócitos pela Via de Sinalização do VEGFR-2

Abstract Background: Pioglitazone has been widely used as an insulin-sensitizing agent for improving glycemic control in patients with type 2 diabetes mellitus. However, cardiovascular risk and protective effects of pioglitazone remain controversial. Objectives: In this study, we investigated whether pioglitazone affects cardiomyocyte apoptosis and hypertrophy by regulating the VEGFR-2 signaling pathway. Methods: Cardiomyocytes were enzymatically isolated from 1- to 3-day-old Sprague-Dawley rat ventricles. Effects of pioglitazone and the VEGFR-2-selective inhibitor apatinib on cardiomyocyte apoptotic rate was determined using flow cytometry, and hypertrophy was evaluated using [3H]-leucine incorporation. The protein expressions of unphosphorylated and phosphorylated VEGFR-2, Akt, P53, and mTOR were determined by Western-Blotting. Analysis of variance (ANOVA) was used to assess the differences between groups. Results: Pioglitazone and VEGFR-2-selective inhibitor apatinib reduced rat cardiomyocyte viability and cardiomyocyte hypertrophy induced by angiotensin II in vitro. Furthermore, in the same in vitro model, pioglitazone and apatinib significantly increased the expression of Bax and phosphorylated P53 and decreased the expression of phosphorylated VEGFR-2, Akt, and mTOR, which promote cardiomyocyte hypertrophy. Conclusions: These findings indicate that pioglitazone induces cardiomyocyte apoptosis and inhibits cardiomyocyte hypertrophy by modulating the VEGFR-2 signaling pathway.

Resumo Fundamento: A pioglitazona tem sido amplamente utilizada como droga sensibilizadora da insulina para melhorar o controle glicêmico em pacientes com diabetes mellitus tipo 2. No entanto, o risco cardiovascular bem como os efeitos protetores da pioglitazona ainda são controversos. Objetivos: Neste estudo, investigamos se os efeitos da pioglitazona sobre a apoptose e a hipertrofia de cardiomiócitos ocorrem via regulação da via de sinalização do VEGFR-2. Métodos: os cardiomiócitos foram isolados enzimaticamente dos ventrículos de ratos Sprague-Dawley de 1-3 anos de vida. Os efeitos da pioglitazona e do inibidor seletivo de VEGFR-2 apatinib sobre a taxa de apoptose dos cardiomiócitos foram avaliados por citometria de fluxo, e a hipertrofia avaliada por incorporação de leucina-[3H]. As expressões de VEGFR-2, Akt, P53, e mTOR fosforiladas e não fosforiladas foram determinadas por Western Blotting. Análise de variância (ANOVA) foi usada para avaliar diferenças entre os grupos. Resultados: a pioglitazona e o apatinib reduziram a viabilidade e a hipertrofia de cardiomiócitos induzida por angiotensina II in vitro. Além disso, no mesmo modelo in vitro, a pioglitazona e o apatinib aumentaram significativamente a expressão de Bax e P53 fosforilada, e diminuiu a expressão de VEGFR-2, Akt, e mTOR, que promove hipertrofia de cardiomiócitos. Conclusões: Esses resultados indicam que a pioglitazona induz a apoptose e inibe a hipertrofia de cardiomiócitos pela modulação da via de sinalização de VEGFR-2.

[RETRACTED ARTICLE] Therapeutic effect and potential mechanism of pioglitazone in rats with severe acute pancreatitis

Caspase recruitment domain-containing protein 9 (Card9) is located upstream of the nuclear factor kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) inflammatory pathways. This study investigated the therapeutic effect and potential mechanism of pioglitazone in rats with severe acute pancreatitis (SAP). SAP was induced by a retrograde infusion of 5.0% sodium taurocholate into the biliopancreatic duct of Sprague Dawley rats (n=54), which were then treated with pioglitazone. Blood and pancreatic tissues were harvested at 3, 6, and 12 h after SAP induction. Pancreatic pathological damage was evaluated by hematoxylin and eosin staining. Serum amylase, serum pro-inflammatory cytokines, and pancreatic myeloperoxidase (MPO) activities were determined by enzyme-linked immunosorbent assay. The expression of Card9 mRNA and protein in pancreatic tissues was detected by real-time polymerase chain reaction and western blotting. Pioglitazone had a therapeutic effect in treating rats with SAP by decreasing the level of amylase activity, ameliorating pancreatic histological damage, decreasing serum pro-inflammatory cytokine levels and tissue MPO activity, and downregulating the expression of NF-κB, p38MAPK, and Card9 mRNAs and proteins (P<0.05). The present study demonstrated that the inhibition of Card9 expression could reduce the severity of SAP. Card9 has a role in the pathogenic mechanism of SAP.

Rosiglitazone role in the expression of KLF6 caco-2 colon cancer cells / Rol de rosiglitazona en la expresión de KLF6 en células caco-2 de cáncer de colon

Kruppel-like factor 6 (KLF6) is a member of the family of Kruppel transcription factors, this plays an important role in the regulation of cell growth, differentiation and angiogenesis. Rosiglitazone is a PPARy agonist drug, its antitumor effect has been described in models of breast and colon cancer. The aim of this study is to evaluate the level of expression of KLF6 in Caco2 cells treated with Avandia. For this a Immunofluorescence was performed, the Caco2 cells were cultured and treated with Rosiglitazone, another group was treated with Rosiglitazone and GW-9662, inhibitor for Immunofluorescence an anti-KLF6 antibody and a secondary antibody coupled to Alexa-488 was used . Cells were observed in a fluorescence microscope and images were processed. The results show that KLF6 is expressed in the cytoplasm of cells Caco2. Compared to treatment with Avandia, KLF6 increases its expression in the cytoplasm. When cells were treated with GW-9662 inhibitor, an expression of KLF6 in the nucleus was observed. KLF6 expression in the cytoplasm of cells Caco2, could be explained by the knowledge of splicing variants SV1 and SV2, these abnormally accumulate in the cytoplasm and promotes cell growth. It is concluded that in untreated Caco 2 cells, KLF6 is expressed in the cytoplasm. Compared to treatment with Rosiglitazone, KLF6 upregulated in the cytoplasm and compared to treatment with the inhibitor, KLF6 is expressed in the nucleus of Caco 2 cells.

Kruppel-like factor 6 (KLF6) is a member of the family of Kruppel transcription factors, this plays an important role in the regulation of cell growth, differentiation and angiogenesis. Rosiglitazone is a PPARy agonist drug, its antitumor effect has been described in models of breast and colon cancer. The aim of this study is to evaluate the level of expression of KLF6 in Caco2 cells treated with Avandia. For this a Immunofluorescence was performed, the Caco2 cells were cultured and treated with Rosiglitazone, another group was treated with Rosiglitazone and GW-9662, inhibitor for Immunofluorescence an anti-KLF6 antibody and a secondary antibody coupled to Alexa-488 was used . Cells were observed in a fluorescence microscope and images were processed. The results show that KLF6 is expressed in the cytoplasm of cells Caco2. Compared to treatment with Avandia, KLF6 increases its expression in the cytoplasm. When cells were treated with GW-9662 inhibitor, an expression of KLF6 in the nucleus was observed. KLF6 expression in the cytoplasm of cells Caco2, could be explained by the knowledge of splicing variants SV1 and SV2, these abnormally accumulate in the cytoplasm and promotes cell growth. It is concluded that in untreated Caco 2 cells, KLF6 is expressed in the cytoplasm. Compared to treatment with Rosiglitazone, KLF6 upregulated in the cytoplasm and compared to treatment with the inhibitor, KLF6 is expressed in the nucleus of Caco 2 cells.

Effect of pioglitazone on serum high density lipoprotein [HDL] levels of type-2 diabetics

Objective: To study effect of Pioglitazone on serum high density lipoprotein levels in patients with type 2 diabetes mellitus

Study Design: Single blind randomized controlled trial

Place and Duration of Study: Department of medicine, Combined Military Hospital Multan from 1[st] Feb 2011 to 30[th] July 2012

Material and Methods: A total of 276 already diagnosed patients of diabetes mellitus type 2 between age of 30-80 years, presenting to the outpatient department of Combined Military Hospital Multan were selected. Type 2 diabetic patients were allocated group A or B using random allocation. Base line blood sugar fasting [BSF], glycosylated hemoglobin [HbAlc], high density lipoprotein [HDL] levels were taken. Group A was treated with Pioglitazone along with other hypoglycemic agents while group B was treated with only hypoglycemic agents and multivitamin tablets were added as placebo.After 12 weeks of treatment, serum HDL levels were measured to analyze effect of pioglitazone on serum HDL levels

Results: Pioglitazone group showed significant improvement in the serum HDL levels from baseline HDL 46.38 + 6.44mmol/L to 49.80+ 5.86 mmol/L after 12 weeks of therapy, [p = 0.001]

Conclusion: Pioglitazone when used in combination with other oral hypoglycemic agents has a beneficial effect on the serum HDL levels of the diabetics

Effect of pioglitazone therapy on high sensitive C-reactive protein and lipid profile in diabetic patients with renal transplantation; a randomize clinical trial

Inflammation has a major role in disease lead to renal failure and diabetes mellitus, controlling inflammation in diabetic kidney receivers could decrease morbidity and mortality. This study designed for evaluating the efficacy of pioglitazone on C-reactive protein and lipid profile in diabetic kidney transplant receivers. In this double blinded clinical trial, 58 diabetic renal transplant receivers, in first month after transplantation, randomized into two groups; receiving insulin and pioglitazone [15 mg tablet daily, group A]; and insulin and placebo [group B]. Blood pressure, weight, body mass index [BMI] and laboratory data compared in before and after 4-month treatment in two groups by SPSS. Fifty-eight patients with mean age of 44.15 +/- 2 years included. There were no significant difference between groups in demographic data and other baseline measured variables [P > 0.05] .The mean weigh and BMI were slightly increased in group A and decreased in group B. The mean hs-CRP was decreased 4.82 mg/dL in group A and 1.93 mg/dL in group B [P = 0.007]. The mean total serum cholesterol was significantly decreased 34 mg/dL in group A and 18.07 mg/dL in group B [P = 0.027]. The mean serum HDL-C was significantly increased 13.31 mg/dL in group A and 5.89 mg/dl in group B [P < 0.001]. Pioglitazone seems to be a safe drug for reducing serum lipids and CRP in kidney transplant receivers with diabetes mellitus in short term. Long term effect of this drug could be evaluated in future studies

Comparative effects of metformin and pioglitazone on lipid profile of rabbits

This is the initial part of study in which the effects of two oral hypoglycemic drugs metformin and pioglitazone were studied on lipid profile of rabbits. White rabbits of both sexes were equally divided in to three groups each comprising of seven animals. Control group was given distilled water 2m1/kg, animals of group II were given metformin in the dose of 22mg/kg and animals of group III received pioglitazone in the dose of 0.5mg/kg. Serum concentration of cholesterol, very low-density lipoprotein [VLDL], triglycerides [TGs], low density lipoprotein [LDL] and high density lipoprotein [HDL] were measured after 8 week of oral dosing. Results shows that after 8 weeks animals received metformin did not reveal any significant change in lipid profile, but animals received pioglitazone showed significant [P<0.05] decrease in lipid profile, the decrease in cholesterol, LDL, VLDL and triglycerides is favorable however decrease in HDL is troublesome and warrant further investigations

Anti-hyperglycemic activity of Rutin in streptozotocin-induced diabetic rats: An effect mediated through cytokines, antioxidants and lipid biomarkers.

Administration of rutin (50 and 100 mg/kg) and pioglitazone (10 mg/kg) orally for 3 weeks treatment significantly improved body weight, reduced plasma glucose and glycosylated hemoglobin, pro-inflammatory cytokines (IL-6 and TNF-α), restored the depleted liver antioxidant status and serum lipid profile in high fat diet + streptozotocin induced type 2 diabetic rats. Rutin treatment also improved histo-architecture of ß islets and reversed hypertrophy of hepatocytes. Rutin exhibited significant antidiabetic activity, presumably by inhibiting inflammatory cytokines, improving antioxidant and plasma lipid profiles in High fat diet + streptozotocin induced type 2 diabetic model and may be useful as a diabetic modulator along with standard antidiabetic drugs. However, such effects need to be confirmed on human subjects in clinical condition.

Cell proliferation and neuroblast differentiation in the dentate gyrus of high-fat diet-fed mice are increased after rosiglitazone treatment

In this study, we determined how rosiglitazone (RSG) differentially affected hippocampal neurogenesis in mice fed a low-fat diet (LFD) or high-fat diet (HFD; 60% fat). LFD and HFD were given to the mice for 8 weeks. Four weeks after initiating the LFD and HFD feeding, vehicle or RSG was administered orally once a day to both groups of mice. We measured cell proliferation and neuroblast differentiation in the subgranular zone of the dentate gyrus using Ki67 and doublecortin (DCX), respectively, as markers. In addition, we monitored the effects of RSG on the levels of DCX and brain-derived neurotrophic factor (BDNF) in hippocampal homogenates. At 8 weeks after the LFD feeding, the numbers of Ki67- and DCX-positive cells as well as hippocampal levels of DCX and BDNF were significantly decreased in the RSG-treated group compared to the vehicle-treated animals. In contrast, the numbers of Ki67- and DCX-positive cells along with hippocampal levels of DCX and BDNF in the HFD fed mice were significantly increased in the RSG-treated mice compared to the vehicle-treated group. Our data demonstrate that RSG can modulate the levels of BDNF, which could play a pivotal role in cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus.

Effect of pioglitazone on lipid profile in type 2 diabetic patients

To determine the effect of pioglitazone on lipid profile in type 2 diabetic patients treated and followed up for three months after initiation of therapy. This hospital based quasi-experimental study was conducted in the medical B unit, Lady Reading Hospital Peshawar from July 2008 to June 2009. A total of 161 patients with type 2 diabetes mellitus were included in this study using convenient [non-probability] sampling. Clinical and laboratory evaluation of all the patients were done to note the change in lipid profile after the use of 30 mg pioglitazone. Continuous variables such as age and lipid profile [triglycerides; Low Density Lipoprotien [LDL]; High Density Lipoprotien [HDL]; cholesterol] at baseline and after 3 months time were expressed as mean +/- S.D. Paired sample t-test was used to analyze the mean difference in pre-post lab investigation by SPSS version15. Out of the 161 patients, 79 [49.1%] were males and 82 [50.9%] were females. The mean age of the sample was 51.2 +/- 11.33 years. Triglycerides decreased from 219.2 +/- 34.4 to 189.2 +/- 33.7 mg/dl with a mean difference of 29.9 mg/dl [p<0.001]. Total cholesterol changed from 201.4 +/- 29.8 to 203.2 +/- 28.9 mg/dl with a mean difference of 1.8mg/dl [p<0.001]. LDL changed from 153.7 +/- 21.1 to 154.7 +/- 20.7 mg/dl with a mean difference of 0.9 mg/dl [p<0.001]. HDL increased from 37.2 +/- 2.9 to 41.5 +/- 3.1 mg/dl with a mean difference of 4.3 mg/dl [p<0.001]. Pioglitazone was found to have beneficial effects on lipid profile. It significantly reduced the levels of triglycerides and increased levels of HDL cholesterol in patients with Type 2 diabetes

effect of pioglitazone on the Alzheimer's disease-induced apoptosis in human umbilical vein endothelial cells

Alzheimer's disease [AD] is a progressive neurodegenerative disease and nowadays the role of endothelial cell [EC] injury has been proposed in pathological process in AD. Peroxisome proliferator-activated receptor- gamma [PPAR- gamma] agonist has anti-inflammatory properties through activation in glial cells and improves vascular function and prevent atherosclerotic disease progression. The aim of this study is evaluation of pioglitazone effects as a drug of PPAR- gamma agonist on endothelial apoptosis induced by sera from AD patients. Human umbilical vein endothelial cells [HUVECs] were treated with sera from AD patients [n = 10] and sera from controls [n = 10]. Apoptosis was identified by annexin V-propidium iodide staining and cell death detection kit. Apoptosis was evaluated after and before adding of 10 micro M pioglitazone on EC. Nitrite [NO[2]] levels were determined in the culture supernatants. Induced apoptosis by the serum of patients was inhibited markedly when pioglitazone used before treating HUVECs with the sera of AD. Also, the measurement of nitrite concentration showed significantly greater levels of dissolved NO[2]/NO[3] metabolite in the culture media of HUVECs treated by sera of AD patients [P < 0.05], while the rate of nitric oxide significantly decreased when pioglitazone exists in culture media. Further studies are justified to investigate the novel role of the PPARs in the prevention of the neuronal and endothelial damage in neurological disorder and present a new therapeutic approach for Alzheimer's patients

PPARgamma modulates vascular smooth muscle cell phenotype via a protein kinase G-dependent pathway and reduces neointimal hyperplasia after vascular injury

Vascular smooth muscle cells (VSMCs) undergo phenotypic changes in response to vascular injury such as angioplasty. Protein kinase G (PKG) has an important role in the process of VSMC phenotype switching. In this study, we examined whether rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, could modulate VSMC phenotype through the PKG pathway to reduce neointimal hyperplasia after angioplasty. In vitro experiments showed that rosiglitazone inhibited the phenotype change of VSMCs from a contractile to a synthetic form. The platelet-derived growth factor (PDGF)-induced reduction of PKG level was reversed by rosiglitazone treatment, resulting in increased PKG activity. This increased activity of PKG resulted in phosphorylation of vasodilator-stimulated phosphoprotein at serine 239, leading to inhibited proliferation of VSMCs. Interestingly, rosiglitazone did not change the level of nitric oxide (NO) or cyclic guanosine monophosphate (cGMP), which are upstream of PKG, suggesting that rosiglitazone influences PKG itself. Chromatin immunoprecipitation assays for the PKG promoter showed that the activation of PKG by rosiglitazone was mediated by the increased binding of Sp1 on the promoter region of PKG. In vivo experiments showed that rosiglitazone significantly inhibited neointimal formation after balloon injury. Immunohistochemistry staining for calponin and thrombospondin showed that this effect of rosiglitazone was mediated by modulating VSMC phenotype. Our findings demonstrate that rosiglitazone is a potent modulator of VSMC phenotype, which is regulated by PKG. This activation of PKG by rosiglitazone results in reduced neointimal hyperplasia after angioplasty. These results provide important mechanistic insight into the cardiovascular-protective effect of PPARgamma.

A study on the short-term effect of cafeteria diet and pioglitazone on insulin resistance and serum levels of adiponectin and ghrelin

The interaction between ghrelin and adiponectin is still controversial. We investigated the effect of cafeteria diet and pioglitazone on body weight, insulin resistance, and adiponectin/ghrelin levels in an experimental study on male Wistar rats. The animals were divided into four groups of 6 rats each, and received balanced chow with saline (CHOW-O) or pioglitazone (CHOW-P), or a cafeteria diet with saline (CAFE-O) or pioglitazone (CAFE-P). The chow/cafeteria diets were administered for 35 days, and saline/pioglitazone (10 mg·kg body weight-1·day-1) was added in the last 14 days prior to euthanasia. CAFE-O animals had a higher mean final weight (372.5 ± 21.01 g) than CHOW-O (317.66 ± 25.11 g, P = 0.017) and CHOW-P (322.66 ± 28.42 g, P = 0.035) animals. Serum adiponectin levels were significantly higher in CHOW-P (55.91 ± 20.62 ng/mL) than in CHOW-O (30.52 ± 6.97 ng/mL, P = 0.014) and CAFE-O (32.54 ± 9.03 ng/mL, P = 0.027) but not in CAFE-P. Higher total serum ghrelin levels were observed in CAFE-P compared to CHOW-P animals (1.65 ± 0.69 vs 0.65 ± 0.36 ng/mL, P = 0.006). Likewise, acylated ghrelin levels were higher in CAFE-P (471.52 ± 195.09 pg/mL) than in CHOW-P (193.01 ± 87.61 pg/mL, P = 0.009) and CAFE-O (259.44 ± 86.36 pg/mL, P = 0.047) animals. In conclusion, a cafeteria diet can lead to a significant weight gain. Although CAFE-P animals exhibited higher ghrelin levels, this was probably related to food deprivation rather than to a direct pharmacological effect, possibly attenuating the increase in adiponectin levels.

Mitochondrial dysfunction and activation of iNOS are responsible for the palmitate-induced decrease in adiponectin synthesis in 3T3L1 adipocytes

Mitochondrial dysfunction and endoplasmic reticulum (ER) stress are considered the key determinants of insulin resistance. Impaired mitochondrial function in obese animals was shown to induce the ER stress response, resulting in reduced adiponectin synthesis in adipocytes. The expression of inducible nitric oxide synthase (iNOS) is increased in adipose tissues in genetic and dietary models of obesity. In this study, we examined whether activation of iNOS is responsible for palmitate-induced mitochondrial dysfunction, ER stress, and decreased adiponectin synthesis in 3T3L1 adipocytes. As expected, palmitate increased the expression levels of iNOS and ER stress response markers, and decreased mitochondrial contents. Treatment with iNOS inhibitor increased adiponectin synthesis and reversed the palmitate-induced ER stress response. However, the iNOS inhibitor did not affect the palmitate-induced decrease in mitochondrial contents. Chemicals that inhibit mitochondrial function increased iNOS expression and the ER stress response, whereas measures that increase mitochondrial biogenesis (rosiglitazone and adenoviral overexpression of nuclear respiratory factor-1) reversed them. Inhibition of mitochondrial biogenesis prevented the rosiglitazone-induced decrease in iNOS expression and increase in adiponectin synthesis. These results suggest that palmitate-induced mitochondrial dysfunction is the primary event that leads to iNOS induction, ER stress, and decreased adiponectin synthesis in cultured adipocytes.

comparison of pioglitazone with metformin in management of type 2 diabetes mellitus

To compare hypoglycemic effect of Pioglitazone and Metformin in type 2 Diabetes Mellitus. Quasi experimental study. Department of Medicine, Military Hospital Rawalpindi Cantt from 11-01-2007 to 12-08-2007. Sixty patients of type 2 diabetes mellitus from outdoor department were selected. On arrival at OPD each patient was examined thoroughly. Therapeutic option was allocated to the patients simply by using a table of random numbers and dividing them in two equal groups. Informed written consent was obtained. Each patient was followed on monthly subsequent visits [six in total] and his HbA1c, fasting and random blood glucose were recorded carefully. All the data thus obtained was processed and analyzed using SPSS version 10.0. Mean and SD were calculated for age, BMI, fasting blood glucose, random blood glucose and HbA1c levels. Mean drop of all three parameters were compared among two groups. At the end of six months, it was revealed that fasting and random [2 hours postprandial] blood glucose dropped more in Pioglitazone group; P=0.000 and 0.02 respectively. While almost comparable effect was observed in HbA1c [P=0.2]. Pioglitazone has significantly better hypoglycemic effect than Metformin in type 2 diabetes mellitus at the end of six months therapy

Duration and Magnitude of Extracellular Signal-Regulated Protein Kinase Phosphorylation Determine Adipogenesis or Osteogenesis in Human Bone Marrow-Derived Stem Cells

PURPOSE: Imbalances between osteogenic and adipogenic differentiation leads to diseases such as osteoporosis. The aim of our study was to demonstrate the differences in extracellular signal-regulated kinase (ERK) phosphorylation during both adipogenesis and osteogenesis of human bone marrow-derived stem cells (BMSCs). MATERIALS AND METHODS: Using troglitazone, GW9662 and U0126, we investigated their role in hBMSC differentiation to adipogenic and osteogenic fates. RESULTS: ERK1/2 inhibition by U0126 suppressed proliferator-activated receptor (PPAR)gamma expression and lipid accumulation, while it decreased the mRNA expression of adipogenic genes (lipoprotein lipase, PPARgamma, and adipocyte protein) and osteogenic genes (type I collagen and osteopontin). ERK phosphorylation was transient and decreased during adipogenesis, whereas it occurred steadily during osteogenesis. Troglitazone, a PPARgamma agonist, induced adipogenesis by inhibiting ERK phosphorylation even in an osteogenic medium, suggesting that ERK signaling needs to be shut off in order to proceed with adipose cell commitment. Cell proliferation was greatly increased in osteogenesis but was not changed during adipogenesis, indicating that ERK might play different roles in cellular proliferation and differentiation between the two committed cell types. CONCLUSION: The duration and magnitude of ERK activation might be a crucial factor for the balance between adipogenesis and osteogenesis in human bone marrow-derived stem cells.

Duration and Magnitude of Extracellular Signal-Regulated Protein Kinase Phosphorylation Determine Adipogenesis or Osteogenesis in Human Bone Marrow-Derived Stem Cells

PURPOSE: Imbalances between osteogenic and adipogenic differentiation leads to diseases such as osteoporosis. The aim of our study was to demonstrate the differences in extracellular signal-regulated kinase (ERK) phosphorylation during both adipogenesis and osteogenesis of human bone marrow-derived stem cells (BMSCs). MATERIALS AND METHODS: Using troglitazone, GW9662 and U0126, we investigated their role in hBMSC differentiation to adipogenic and osteogenic fates. RESULTS: ERK1/2 inhibition by U0126 suppressed proliferator-activated receptor (PPAR)gamma expression and lipid accumulation, while it decreased the mRNA expression of adipogenic genes (lipoprotein lipase, PPARgamma, and adipocyte protein) and osteogenic genes (type I collagen and osteopontin). ERK phosphorylation was transient and decreased during adipogenesis, whereas it occurred steadily during osteogenesis. Troglitazone, a PPARgamma agonist, induced adipogenesis by inhibiting ERK phosphorylation even in an osteogenic medium, suggesting that ERK signaling needs to be shut off in order to proceed with adipose cell commitment. Cell proliferation was greatly increased in osteogenesis but was not changed during adipogenesis, indicating that ERK might play different roles in cellular proliferation and differentiation between the two committed cell types. CONCLUSION: The duration and magnitude of ERK activation might be a crucial factor for the balance between adipogenesis and osteogenesis in human bone marrow-derived stem cells.

Targeting CYP450 modulation to decrease the risk of induced cataract in the experimental model.

Background: Diabetes is one of the major causes of cataract. Some drugs prescribed for the treatment of diabetes are the modulators of CYP450, which may alter the risk of cataract. Objective: To study the effect of CYP450 modulation in galactosemic cataract. Materials and Methods: Male Sprague-Dawley suckling rats were allotted to four groups (n = 6), as follows: Group 1: Normal control, Group 2: Galactose control, Group 3: CYP450 inhibitor pretreated and Group 4: CYP450 inducer pretreated. Cataract was induced in animals of all groups except group 1 by feeding them galactose (50%), 21 days after parturition. From the eighteenth day of life, CYP450 inhibitor (nifedipine; 8.1 mg/kg) and CYP450 inducer (pioglitazone; 3.8 mg/kg) were given orally to groups 3 and 4, respectively. The maturation pattern of the cataract was observed by an operating microscope, every third day. Biochemical changes in the lenses of all groups, for example, CYP450 activity expressed as µM NADPH oxidized / unit time, alterations in the levels of total proteins, soluble proteins, and reduced glutathione (GSH) following the induction of cataract, were estimated. Results: The microscopic examination of the lenses indicated that CYP450 inhibitor pre-treatment delayed (fourteenth day) the occurrence of cataract, while CYP450 inducer pretreatment demonstrated an early (ninth day) cataract as compared to galactose control rats (twelfth day). A significant decrease and increase in CYP450 activity was observed with the CYP450 inhibitor and inducer pre-treatment, respectively. There was no alteration in the GSH level, but a significant increase in total and soluble protein was found in groups 3 and 4 as compared to group 2. Conclusion: CYP450 may have a role in the initiation of cataract without any effect on the maturation pattern, as revealed by the delayed occurrence of cataract with the CYP450 inhibitor and an early onset of cataract with the CYP450 inducer.

Rosiglitazona e lesão vascular em coelhos hipercolesterolêmicos: avaliação da formação neointimal / Rosiglitazone and vascular injury in hypercholesterolemic rabbits: neointimal formation assessment / Rosiglitazona y lesión vascular en conejos hipercolesterolémicos

FUNDAMENTO: O uso da rosiglitazona tem sido o objeto de extensas discussões. OBJETIVO: Avaliar os efeitos da rosiglitazona nas artérias ilíacas, no local da injúria e na artéria contralateral, de coelhos hipercolesterolêmicos submetidos à lesão por cateter-balão. MÉTODOS: Coelhos brancos machos receberam uma dieta hipercolesterolêmica através de gavagem oral por 6 semanas e foram divididos em 2 grupos: grupo rosiglitazona (GR - 14 coelhos tratados com rosiglitazona por 6 semanas) e grupo controle (GC - 18 coelhos sem rosiglitazona). Os animais foram submetidos a lesão por cateter-balão na artéria ilíaca direita no 14º dia. RESULTADOS: Na artéria ilíaca contralateral, não houve diferença significante na razão entre as áreas intimal e medial (RIM) entre os grupos GR e GC. A rosiglitazona não reduziu a probabilidade de lesões tipo I, II ou III (72,73 por cento vs 92,31 por cento; p=0,30) e lesões tipo IV ou V (27,27 por cento vs 7,69 por cento; p=0,30). Na artéria ilíaca homolateral, a área intimal era significantemente menor no GR quando comparado ao GC (p = 0,024). A área luminal era maior no GR quando comparado ao GC (p < 0,0001). Houve uma redução significante de 65 por cento na IMR no GR quando comparado ao GC (p = 0,021). Nenhum dos critérios histológicos para lesões ateroscleróticas tipos I a V (American Heart Association) foram encontrados na artéria ilíaca homolateral. CONCLUSÃO: Esses achados demonstram que a administração de rosiglitazona por 6 semanas impede a aterogênese no local da lesão, mas não em um vaso distante do sítio da lesão.

BACKGROUND: Rosiglitazone has been the focus of extensive discussion. OBJECTIVE: To evaluate the effects of rosiglitazone on iliac arteries, both at the injury site and the contralateral artery, of hypercholesterolemic rabbits undergoing balloon catheter injury. METHODS: White male rabbits were fed a hypercholesterolemic diet by oral gavage for 6 weeks and divided into two groups as follows: rosiglitazone group (14 rabbits treated with rosiglitazone during 6 weeks) and the control group (18 rabbits without rosiglitazone). Animals underwent balloon catheter injury of the right iliac artery on the 14th day. RESULTS: In the contralateral iliac artery, there was no significant difference in the intima/media layer area ratio (IMR) between the control and rosiglitazone groups. Rosiglitazone did not reduce the probability of type I, II, or III lesions (72.73 percent vs 92.31 percent; p=0.30) and type IV or V lesions (27.27 percent vs 7.69 percent; p=0.30). As for the homolateral iliac artery, the intimal area was significantly lower in the rosiglitazone group, as compared to the control group (p = 0.024). The luminal layer area was higher in the rosiglitazone group vs. the control group (p < 0.0001). There was a significant reduction of 65 percent in the IMR in the rosiglitazone group vs the control group (p = 0.021). None of the histological criteria for type I-V atherosclerotic lesions (American Heart Association) were found in the homolateral iliac artery. CONCLUSION: These findings demonstrate that rosiglitazone given for 6 weeks prevents atherogenesis at the injury site, but not in a vessel distant from the injury site.

FUNDAMENTO: El uso de rosiglitazona ha estado siendo el objeto de extensas discusiones. OBJETIVO: Evaluar los efectos de la rosiglitazona en las arterias ilíacas, en el local de la injuria y en la arteria contralateral, de conejos hipercolesterolémicos sometidos a la lesión por catéter-balón. MÉTODOS: Conejos blancos machos recibieron una dieta hipercolesterolémica a través de gavage oral por 6 semanas y se los dividieron en 2 grupos: grupo rosiglitazona (GR - 14 conejos tratados con rosiglitazona por 6 semanas) y grupo control (GC - 18 conejos sin rosiglitazona). Los animales se sometieron a lesión por catéter-balón en la arteria ilíaca derecha en el 14º día. RESULTADOS: En la arteria ilíaca contralateral, no hubo diferencia significativa en la razón entre las áreas íntima y media (RIM) entre los grupos GR y GC. La rosiglitazona no redujo la probabilidad de lesiones tipo I, II ó III (72,73 por ciento vs 92,31 por ciento; p=0,30) y lesiones tipo IV ó V (27,27 por ciento vs 7,69 por ciento; p=0,30). En la arteria ilíaca homolateral, el área intima era significantemente menor en el GR cuando comparado al GC (p = 0,024). El área luminal era mayor en el GR cuando comparado al GC (p < 0,0001). Hubo una reducción significante del 65 por ciento en la IMR en el GR cuando comparado al GC (p = 0,021). Ningún de los criterios histológicos para lesiones ateroscleróticas tipos I a V (American Heart Association) se encontraron en la arteria ilíaca homolateral. CONCLUSIÓN: Estos hallazgos demuestran que la administración de rosiglitazona por 6 semanas impide la aterogénesis en el local de la lesión, pero no en un vaso distante del sitio de la lesión.

Pioglitazone, a ppar-gamma ligand inhibited the nicotinamide streptozotocin induced sperm abnormalities in type-2 diabetic wistar rats

Oxidative stress due to chronic hyperglycemia is known to cause infertility in diabetic patients. Pioglitazone [PIO], a PPAR-gamma ligand is known to possess the antioxidant property however, its role on the oxidative stress mediated germinal damage in Type-2 diabetes mellitus [T2DM] is poorly studies in the literature. In this study, the effect of PIO [1 and 10 mg/kg, p.o. daily for 4 weeks] was evaluated against the nicotinamide [NA-230 mg/kg, ip] and streptozotocin [STZ-65 mg/kg, ip] induced changes in sperm abnormality and antioxidant status in Wistar rats. The effect of PIO on the male reproductive cells was studied by determining the sperm shape abnormality and sperm count in the experimental T2DM. The antioxidant profile was studied by estimating the serum lipid peroxidation [LPO], glutathione [GSH] and glutathione peroxidase [GPx] levels. The higher dose of PIO [10 mg/kg] significantly [P<0.001] reduced the sperm shape abnormality and increased the sperm count [P<0.00l], besides decreasing [P<0.05] the LPO and enhancing the GSH and GPx levels in the diabetic rats. However, the lower dose of PIO [1 mg/kg] produced inhibitory [P<0.05] effect against the changes induced by T2DM in the sperm shape abnormality and GSH levels. alpha tocopherol tested as alpha standard antioxidant agent prevented [P<0.001] the NA-STZ mediated alterations in sperm abnormalities and antioxidant enzyme levels. The results suggest that the inhibitory effect of PIO against the 12DM induced sperm abnormality could be related to its antioxidant property

The Effect of Rosiglitazone on the Cell Proliferation and the Expressions of p27 and Skp2 in Helicobacter pylori Infected Human Gastric Epithelial Cells / 대한소화기학회지

BACKGROUND/AIMS: Ligands for peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of the ligand-activated nuclear receptor superfamily, exhibit anti-tumoral effects and are associated with de novo synthesis of proteins involved in regulating the cell cycle and cell survival/death. Helicobacter pylori (H. pylori) is an etiologic agent for gastric adenocarcinoma, and raises the cell turnover of gastric epithelium. The aim of this study was to investigate the effect of PPAR gamma ligand rosiglitazone on the cell proliferation and the expressions of p27 and Skp2 protein in H. pylori infected gastric epithelial cells. METHODS: We examined the expression of PPAR gamma by Western blot in H. pylori infected AGS human gastric epithelial cells. The effect of rosiglitazone on the survival of H. pylori infected AGS cells was assessed by cell viability assay. After the treatment of rosiglitazone in H. pylori infected AGS cells, the expressions of p27 and Skp2 were assessed by Western blot. RESULTS: The expression of PPAR gamma protein was increased in H. pylori infected AGS cells. Cell growth was inhibited and decreased in dose- and time- dependent manner in H. pylori infected AGS cells treated with rosiglitazone. A decrease in Skp2 expression and a reciprocal increase in p27 expression were found in dose- and time-dependent manner in H. pylori infected AGS cells treated with rosiglitazone. CONCLUSIONS: Rosiglitazone inhibited the growth of H. pylori infected AGS cells. Rosiglitazone attenuated Skp2 expression, thereby promoting p27 accumulation in H. pylori infected human gastric epithelial cells. Further studies will be needed to find the effects of accumulation on cell turnover in H. pylori infection and the role in the H. pylori-associated gastric carcinogenesis.