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1.  Downregulation of the Proinflammatory State of Circulating Mononuclear Cells by Short-Term Treatment with Pioglitazone in Patients with Type 2 Diabetes Mellitus and Coronary Artery Disease 
PPAR Research  2011;2011:647017.
Background. This study was performed to investigate the influence of a short-term treatment with pioglitazone versus placebo on inflammatory activation of mononuclear cells (mRNA expression/protein secretion of inflammatory markers). Methods and Results. Sixty-three patients with well-controlled type 2 diabetes (52 males, 11 females, age (Mean ± SD): 66 ± 7 yrs, disease duration: 6.6 ± 9.6 yrs, HbA1c: 6.7 ± 0.6%) were randomized to additional 45 mg of pioglitazone or placebo to their existing metformin and sulfonylurea therpay for four weeks in a double-blind study design. Protein risk marker levels (hsCRP, MMP-9, MCP-1, etc.) and the expression of NFκB subunits and NFκB-modulated cytokines from isolated peripheral monocyte/macrophages were determined at baseline and endpoint. There were no changes in HbA1c, but significant biomarker improvements were seen with pioglitazone only. The mRNA marker expression was downregulated by pioglitazone and further up-regulated with placebo (e.g., P105 pioglitazone: −19%/placebo: +6%, RelA: −20%/+2%, MMP−9: −36%/+9%, TNFα: −10%/+14%, P < 0.05 between groups in all cases). Conclusions. Pioglitazone very rapidly down-regulated the activated state of peripheral monocytes/macrophages as assessed by mRNA expression of NFκB and NFκB-modulated cytokines and decreased plasma levels of cardiovascular risk marker proteins independent of glycemic control.
PMCID: PMC3144663  PMID: 21808640
2.  Fruit and vegetable consumption and proinflammatory gene expression from peripheral blood mononuclear cells in young adults: a translational study 
Fruits and vegetables are important sources of fiber and nutrients with a recognized antioxidant capacity, which could have beneficial effects on the proinflammatory status as well as some metabolic syndrome and cardiovascular disease features. The current study assessed the potential relationships of fruit and vegetable consumption with the plasma concentrations and mRNA expression values of some proinflammatory markers in young adults.
One-hundred and twenty healthy subjects (50 men/70 women; 20.8 ± 2.6 y; 22.3 ± 2.8 kg/m2) were enrolled. Experimental determinations included anthropometry, blood pressure and lifestyle features as well as blood biochemical and inflammatory measurements. The mRNA was isolated from peripheral blood mononuclear cells (PBMC) and the gene expression concerning selected inflammatory markers was assessed by quantitative real-time PCR. Nutritional intakes were estimated by a validated semi-quantitative food-frequency questionnaire.
The highest tertile of energy-adjusted fruit and vegetable consumption (>660 g/d) was associated with lower plasma concentrations of C-reactive protein (CRP) and homocysteine and with lower ICAM1, IL1R1, IL6, TNFα and NFκB1 gene expression in PBMC (P for trend < 0.05), independently of gender, age, energy intake, physical activity, smoking, body mass index, systolic blood pressure and circulating non-esterified fatty acids. In addition, plasma CRP, homocysteine and TNFα concentrations and ICAM1, TNFα and NFκB1 gene expression in PBMC showed a descending trend as increased fiber intake (>19.5 g/d) from fruits and vegetables (P for trend < 0.05). Furthermore, the participants within the higher tertile (>11.8 mmol/d) of dietary total antioxidant capacity showed lower plasma CRP and mRNA values of ICAM1, IL1R1, IL6, TNFα and NFκB1 genes (P for trend < 0.05). The inverse association between fruit and vegetable consumption and study proinflammatory markers followed the same trend and remained statistically significant, after the inclusion of other foods/nutrients in the linear regression models.
A higher fruit and vegetable consumption was independently associated not only with reduced CRP and homocysteine concentrations but also with a lower mRNA expression in PBMC of some relevant proinflammatory markers in healthy young adults.
PMCID: PMC2882916  PMID: 20465828
3.  PPARγ activation but not PPARγ haplodeficiency affects proangiogenic potential of endothelial cells and bone marrow-derived progenitors 
Cardiovascular Diabetology  2014;13(1):150.
Peroxisome proliferator-activated receptor-γ (PPARγ) agonists, which have been used as insulin sensitizers in diabetic patients, may improve functions of endothelial cells (ECs). We investigated the effect of PPARγ on angiogenic activities of murine ECs and bone marrow-derived proangiogenic cells (PACs).
PACs were isolated from bone marrow of 10–12 weeks old, wild type, db/db and PPARγ heterozygous animals. Cells were cultured on fibronectin and gelatin coated dishes in EGM-2MV medium. For in vitro stimulations, rosiglitazone (10 μmol/L) or GW9662 (10 μmol/L) were added to 80% confluent cell cultures for 24 hours. Angiogenic potential of PACs and ECs was tested in vitro and in vivo in wound healing assay and hind limb ischemia model.
ECs and PACs isolated from diabetic db/db mice displayed a reduced angiogenic potential in ex vivo and in vitro assays, the effect partially rescued by incubation of cells with rosiglitazone (PPARγ activator). Correction of diabetes by administration of rosiglitazone in vivo did not improve angiogenic potential of isolated PACs or ECs. In a hind limb ischemia model we demonstrated that local injection of conditioned media harvested from wild type PACs improved the blood flow restoration in db/db mice, confirming the importance of paracrine action of the bone marrow-derived cells.
Transcriptome analysis showed an upregulation of prooxidative and proinflammatory pathways, and downregulation of several proangiogenic genes in db/db PACs. Interestingly, db/db PACs had also a decreased level of PPARγ and changed expression of PPARγ-regulated genes. Using normoglycemic PPARγ+/− mice we demonstrated that reduced expression of PPARγ does not influence neovascularization either in wound healing or in hind limb ischemia models.
In summary, activation of PPARγ by rosiglitazone improves angiogenic potential of diabetic ECs and PACs, but decreased expression of PPARγ in diabetes does not impair angiogenesis.
Electronic supplementary material
The online version of this article (doi:10.1186/s12933-014-0150-7) contains supplementary material, which is available to authorized users.
PMCID: PMC4233236  PMID: 25361524
Diabetes; PPARγ; Therapeutic angiogenesis; Endothelial progenitor cells
4.  Inflammation, Insulin Resistance, and Diabetes—Mendelian Randomization Using CRP Haplotypes Points Upstream 
PLoS Medicine  2008;5(8):e155.
Raised C-reactive protein (CRP) is a risk factor for type 2 diabetes. According to the Mendelian randomization method, the association is likely to be causal if genetic variants that affect CRP level are associated with markers of diabetes development and diabetes. Our objective was to examine the nature of the association between CRP phenotype and diabetes development using CRP haplotypes as instrumental variables.
Methods and Findings
We genotyped three tagging SNPs (CRP + 2302G > A; CRP + 1444T > C; CRP + 4899T > G) in the CRP gene and measured serum CRP in 5,274 men and women at mean ages 49 and 61 y (Whitehall II Study). Homeostasis model assessment-insulin resistance (HOMA-IR) and hemoglobin A1c (HbA1c) were measured at age 61 y. Diabetes was ascertained by glucose tolerance test and self-report. Common major haplotypes were strongly associated with serum CRP levels, but unrelated to obesity, blood pressure, and socioeconomic position, which may confound the association between CRP and diabetes risk. Serum CRP was associated with these potential confounding factors. After adjustment for age and sex, baseline serum CRP was associated with incident diabetes (hazard ratio = 1.39 [95% confidence interval 1.29–1.51], HOMA-IR, and HbA1c, but the associations were considerably attenuated on adjustment for potential confounding factors. In contrast, CRP haplotypes were not associated with HOMA-IR or HbA1c (p = 0.52–0.92). The associations of CRP with HOMA-IR and HbA1c were all null when examined using instrumental variables analysis, with genetic variants as the instrument for serum CRP. Instrumental variables estimates differed from the directly observed associations (p = 0.007–0.11). Pooled analysis of CRP haplotypes and diabetes in Whitehall II and Northwick Park Heart Study II produced null findings (p = 0.25–0.88). Analyses based on the Wellcome Trust Case Control Consortium (1,923 diabetes cases, 2,932 controls) using three SNPs in tight linkage disequilibrium with our tagging SNPs also demonstrated null associations.
Observed associations between serum CRP and insulin resistance, glycemia, and diabetes are likely to be noncausal. Inflammation may play a causal role via upstream effectors rather than the downstream marker CRP.
Using a Mendelian randomization approach, Eric Brunner and colleagues show that the associations between serum C-reactive protein and insulin resistance, glycemia, and diabetes are likely to be noncausal.
Editors' Summary
Diabetes—a common, long-term (chronic) disease that causes heart, kidney, nerve, and eye problems and shortens life expectancy—is characterized by high levels of sugar (glucose) in the blood. In people without diabetes, blood sugar levels are controlled by the hormone insulin. Insulin is released by the pancreas after eating and “instructs” insulin-responsive muscle and fat cells to take up the glucose from the bloodstream that is produced by the digestion of food. In the early stages of type 2 diabetes (the commonest type of diabetes), the muscle and fat cells become nonresponsive to insulin (a condition called insulin resistance), and blood sugar levels increase. The pancreas responds by making more insulin—people with insulin resistance have high blood levels of both insulin and glucose. Eventually, however, the insulin-producing cells in the pancreas start to malfunction, insulin secretion decreases, and frank diabetes develops.
Why Was This Study Done?
Globally, about 200 million people have diabetes, but experts believe this number will double by 2030. Ways to prevent or delay the onset of diabetes are, therefore, urgently needed. One major risk factor for insulin resistance and diabetes is being overweight. According to one theory, increased body fat causes mild, chronic tissue inflammation, which leads to insulin resistance. Consistent with this idea, people with higher than normal amounts of the inflammatory protein C-reactive protein (CRP) in their blood have a high risk of developing diabetes. If inflammation does cause diabetes, then drugs that inhibit CRP might prevent diabetes. However, simply measuring CRP and determining whether the people with high levels develop diabetes cannot prove that CRP causes diabetes. Those people with high blood levels of CRP might have other unknown factors in common (confounding factors) that are the real causes of diabetes. In this study, the researchers use “Mendelian randomization” to examine whether increased blood CRP causes diabetes. Some variants of CRP (the gene that encodes CRP) increase the amount of CRP in the blood. Because these variants are inherited randomly, there is no likelihood of confounding factors, and an association between these variants and the development of insulin resistance and diabetes indicates, therefore, that increased CRP levels cause diabetes.
What Did the Researchers Do and Find?
The researchers measured blood CRP levels in more than 5,000 people enrolled in the Whitehall II study, which is investigating factors that affect disease development. They also used the “homeostasis model assessment-insulin resistance” (HOMA-IR) method to estimate insulin sensitivity from blood glucose and insulin measurements, and measured levels of hemoglobin A1c (HbA1c, hemoglobin with sugar attached—a measure of long-term blood sugar control) in these people. Finally, they looked at three “single polynucleotide polymorphisms” (SNPs, single nucleotide changes in a gene's DNA sequence; combinations of SNPs that are inherited as a block are called haplotypes) in CRP in each study participant. Common haplotypes of CRP were related to blood serum CRP levels and, as previously reported, increased blood CRP levels were associated with diabetes and with HOMA-IR and HbA1c values indicative of insulin resistance and poor blood sugar control, respectively. By contrast, CRP haplotypes were not related to HOMA-IR or HbA1c values. Similarly, pooled analysis of CRP haplotypes and diabetes in Whitehall II and another large study on health determinants (the Northwick Park Heart Study II) showed no association between CRP variants and diabetes risk. Finally, data from the Wellcome Trust Case Control Consortium also showed no association between CRP haplotypes and diabetes risk.
What Do These Findings Mean?
Together, these findings suggest that increased blood CRP levels are not responsible for the development of insulin resistance or diabetes, at least in European populations. It may be that there is a causal relationship between CRP levels and diabetes risk in other ethnic populations—further Mendelian randomization studies are needed to discover whether this is the case. For now, though, these findings suggest that drugs targeted against CRP are unlikely to prevent or delay the onset of diabetes. However, they do not discount the possibility that proteins involved earlier in the inflammatory process might cause diabetes and might thus represent good drug targets for diabetes prevention.
Additional Information.
Please access these Web sites via the online version of this summary at
This study is further discussed in a PLoS Medicine Perspective by Bernard Keavney
The MedlinePlus encyclopedia provides information about diabetes and about C-reactive protein (in English and Spanish)
US National Institute of Diabetes and Digestive and Kidney Diseases provides patient information on all aspects of diabetes, including information on insulin resistance (in English and Spanish)
The International Diabetes Federation provides information about diabetes, including information on the global diabetes epidemic
The US Centers for Disease Control and Prevention provides information for the public and professionals on all aspects of diabetes (in English and Spanish)
Wikipedia has a page on Mendelian randomization (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC2504484  PMID: 18700811
5.  Elevated Toll-Like Receptor 4 Expression and Signaling in Muscle From Insulin-Resistant Subjects 
Diabetes  2008;57(10):2595-2602.
OBJECTIVE— Tall-like receptor (TLR)4 has been implicated in the pathogenesis of free fatty acid (FFA)-induced insulin resistance by activating inflammatory pathways, including inhibitor of κB (IκB)/nuclear factor κB (NFκB). However, it is not known whether insulin-resistant subjects have abnormal TLR4 signaling. We examined whether insulin-resistant subjects have abnormal TLR4 expression and TLR4-driven (IκB/NFκB) signaling in skeletal muscle.
RESEARCH DESIGN AND METHODS— TLR4 gene expression and protein content were measured in muscle biopsies in 7 lean, 8 obese, and 14 type 2 diabetic subjects. A primary human myotube culture system was used to examine whether FFAs stimulate IκB/NFκB via TLR4 and whether FFAs increase TLR4 expression/content in muscle.
RESULTS— Obese and type 2 diabetic subjects had significantly elevated TLR4 gene expression and protein content in muscle. TLR4 muscle protein content correlated with the severity of insulin resistance. Obese and type 2 diabetic subjects also had lower IκBα content, an indication of elevated IκB/NFκB signaling. The increase in TLR4 and NFκB signaling was accompanied by elevated expression of the NFκB-regulated genes interleukin (IL)-6 and superoxide dismutase (SOD)2. In primary human myotubes, acute palmitate treatment stimulated IκB/NFκB, and blockade of TLR4 prevented the ability of palmitate to stimulate the IκB/NFκB pathway. Increased TLR4 content and gene expression observed in muscle from insulin-resistant subjects were reproduced by treating myotubes from lean, normal-glucose-tolerant subjects with palmitate. Palmitate also increased IL-6 and SOD2 gene expression, and this effect was prevented by inhibiting NFκB.
CONCLUSIONS— Abnormal TLR4 expression and signaling, possibly caused by elevated plasma FFA levels, may contribute to the pathogenesis of insulin resistance in humans.
PMCID: PMC2551667  PMID: 18633101
6.  Intensification of oxidative stress and inflammation in type 2 diabetes despite antihyperglycemic treatment 
The metabolic deregulation associated with diabetes mellitus (DM) causes secondary pathophysiologic changes in multiple organ systems. Endothelial injury is induced by oxidative stress (OS) and inflammation. We have previously shown that DM type 2 patients are exposed to increased OS and inflammation contributed in part by primed peripheral polymorphonuclear leukocytes (PMNLs).
To characterize the effect of oral medication on PMNL priming, on PMNL-related and on systemic inflammation, in correlation to changed diabetes parameters in patient with newly diagnosed type 2 DM.
PMNLs were separated from DM patient's prior and following treatment with either metformin (Glucophage), or Thiazolidinedione (rosiglitazone) and from healthy control subjects (HC). Rate of superoxide release from phorbol ester-stimulated PMNLs and CD11b on PMNLs assessed PMNL priming. White blood cells (WBC) and PMNL counts and apoptosis reflected PMNL-related inflammation. CRP, fibrinogen, transferrin and albumin blood levels reflected systemic inflammation.
Both metformin and rosiglitazone treatments reduced significantly the high levels of glucose and HbA1c, and slightly improved lipid profile during 2 months. PMNL priming parameters, higher compared to HC, increased after 2 months of metformin treatment. Rosiglitazone treatment decreased PMNL priming. ALP, higher in DM, significantly decreased following 2 months of both treatments. Systemic inflammation markers (fibrinogen, CRP), higher in DM, decreased following both treatments. Transferrin and albumin were similar to HC. PMNL-related inflammation markers were higher in DM; however, only PMNL apoptosis decreased after both treatments. Monocyte counts, higher in DM compared to HC, decreased following both treatments. Serum insulin levels, higher in DM compared to HC, decreased following both treatments. PMNL-related priming and inflammation parameters positively correlated with HbA1c.
The present research adds new facet in evaluating anti-hyperglycemic treatment in type 2 DM patients. Despite sufficient glycemic control using both treatments, some PMNL-related parameters deteriorated. Thus, anti hyperglycemic treatment should be favored due to its combined anti-PMNL priming and anti-inflammatory effect, in addition to its anti-hyperglycemic characteristics, according to the correlation among these parameters. Such combined treatment may reduce morbidity and mortality common in DM patients.
PMCID: PMC2441608  PMID: 18570678
7.  Serum C-Reactive Protein Levels in Normal-Weight Polycystic Ovary Syndrome 
Serum levels of highly sensitive C-reactive protein (hsCRP), a vascular inflammatory marker, may predict the development of cardiovascular disease (CVD) and type 2 diabetes. Women with polycystic ovary syndrome (PCOS) are at greater risk for type 2 diabetes and CVD. The aim of this study was to compare hsCRP levels between normal weight women with PCOS and controls with a normal menstrual cycle and to determine the factors associated with serum hsCRP levels.
Thirty-nine lean PCOS patients and 24 healthy, regular cycling women were enrolled in this study. We performed anthropometric measurements, fat computed tomography (CT), and blood sampling to determine blood chemistry and levels of hsCRP, gonadotropins, testosterone, and sex-hormone binding globulin. We also conducted 75-g oral glucose-tolerance test and euglycemic hyperinsulinemic clamp to assess insulin sensitivity.
Serum hsCRP concentrations were higher in women with PCOS than in women with regular mensturation. However, this difference was no longer significant after adjusting for body mass index (BMI). hsCRP levels were correlated with waist circumference (r=0.46, p<0.01), BMI (r=0.46, p<0.01), visceral fat area (r=0.45, p<0.01), and systolic (r=0.42, p<0.05) and diastolic blood pressure (r=0.39, p<0.05). hsCRP also tended to be negatively associated with insulin-mediated glucose uptake (IMGU) (r=-0.31, p=0.07). A multiple regression analysis revealed that BMI (β=0.29, p<0.05), systolic blood pressure (β=0.39, p<0.01), and IMGU (β=-0.31, p<0.05) predicted serum hsCRP levels in women with PCOS.
PCOS by itself does not seem to be associated with increased hsCRP levels, whereas known CVD risk factors affect serum hsCRP levels in PCOS.
PMCID: PMC2784979  PMID: 19949734
Cardiovascular disease; C-reactive protein; Polycystic ovary syndrome
8.  Butyrate inhibits inflammatory responses through NFκB inhibition: implications for Crohn's disease 
Gut  2000;47(3):397-403.
BACKGROUND/AIM—Proinflammatory cytokines are key factors in the pathogenesis of Crohn's disease (CD). Activation of nuclear factor kappa B (NFκB), which is involved in their gene transcription, is increased in the intestinal mucosa of CD patients. As butyrate enemas may be beneficial in treating colonic inflammation, we investigated if butyrate promotes this effect by acting on proinflammatory cytokine expression.
METHODS—Intestinal biopsy specimens, isolated lamina propria cells (LPMC), and peripheral blood mononuclear cells (PBMC) were cultured with or without butyrate for assessment of secretion of tumour necrosis factor (TNF) and mRNA levels. NFκB p65 activation was determined by immunofluorescence and gene reporter experiments. Levels of NFκB inhibitory protein (IκBα) were analysed by western blotting. The in vivo efficacy of butyrate was assessed in rats with trinitrobenzene sulphonic acid (TNBS) induced colitis.
RESULTS—Butyrate decreased TNF production and proinflammatory cytokine mRNA expression by intestinal biopsies and LPMC from CD patients. Butyrate abolished lipopolysaccharide (LPS) induced expression of cytokines by PBMC and transmigration of NFκB from the cytoplasm to the nucleus. LPS induced NFκB transcriptional activity was decreased by butyrate while IκBα levels were stable. Butyrate treatment also improved TNBS induced colitis.
CONCLUSIONS—Butyrate decreases proinflammatory cytokine expression via inhibition of NFκB activation and IκBα degradation. These anti-inflammatory properties provide a rationale for assessing butyrate in the treatment of CD.

Keywords: inflammation; butyrate; Crohn's disease; nuclear factor kappa B; cytokines
PMCID: PMC1728045  PMID: 10940278
9.  Peroxisome proliferator-activated receptor γ agonist reduces the severity of post-ERCP pancreatitis in rats 
AIM: To determine the effects of prophylactic peroxi-some proliferator-activated receptor (PPARγ) agonist administration in an experimental model of post-endoscopic retrograde cholangiopancreatography (post-ERCP) acute pancreatitis.
METHODS: Post-ERCP pancreatitis was induced in male Wistar rats by infusion of contrast medium into the pancreatic duct. In additional group, rosiglitazone, a PPARγ agonist, was administered 1 h before infusion of contrast medium. Plasma and pancreas samples were obtained 6 h after the infusion.
RESULTS: Infusion of contrast medium into the pan-creatic duct resulted in an inflammatory process characterized by increased lipase levels in plasma, and edema and myeloperoxidase activity (MPO) in pancreas. This result correlated with the activation of nuclear factor κB (NFκB) and the inducible NO synthase (iNOS) expression in pancreatic cells. Rosiglitazone reduced the increase in lipase and the level of edema and the increase in myeloperoxidase as well as the activation of NFκB and iNOS expression.
CONCLUSION: A single oral dose of rosiglitazone, given 1 h before post-ERCP pancreatitis induction is effective in reducing the severity of the subsequent inflammatory process. The protective effect of rosiglitazone was associated with NFκB inhibition and the blockage of leukocyte infiltration in pancreas.
PMCID: PMC4100635  PMID: 17072978
Peroxisome proliferator-activated receptor γ; Pancreatitis; Endoscopic retrograde cholangio pancreatography; Inflammation; Nuclear factor κB
10.  Autonomic neuropathy predisposes to rosiglitazone-induced vascular leakage in insulin-treated patients with type 2 diabetes: a randomised, controlled trial on thiazolidinedione-induced vascular leakage 
Diabetologia  2010;53(9):1856-1866.
The mechanism of fluid-related complications caused by thiazolidinedione derivatives is unclear. One potential mechanism is thiazolidinedione-induced arterial vasodilatation, which results in vascular leakage and a fall in blood pressure, normally counterbalanced by sympathetic activation and subsequent renal fluid retention. We hypothesised that thiazolidinedione-induced vascular leakage will be particularly prominent in patients with autonomic neuropathy.
We conducted a randomised, double-blind, placebo-controlled, parallel study in 40 patients with type 2 diabetes on insulin treatment recruited from a university medical centre. The randomisation was performed by a central office using a randomisation schedule. Both treatment groups, placebo (n = 21) and rosiglitazone (n = 19), were stratified for sex and level of autonomic neuropathy as assessed by Ewing score (<2.5 or ≥2.5). We investigated the effects of 16 weeks of treatment with rosiglitazone 4 mg twice daily on vascular leakage (transcapillary escape rate of albumin, TERalb), body weight, extracellular volume and plasma volume.
Thirty-nine patients were included in the analysis. In patients with high Ewing scores (n = 16), rosiglitazone increased TERalb significantly (ΔTERalb: rosiglitazone +2.43 ± 0.45%/h, placebo −0.11 ± 0.15%/h, p = 0.002), while rosiglitazone had no effect in the patients with low Ewing scores (n = 23). Rosiglitazone-induced increases in TERalb and Ewing score at baseline were correlated (r = 0.65, p = 0.02). There was no correlation between Ewing score and rosiglitazone-induced changes in fluid variables. One subject was withdrawn from the study because of atrial fibrillation.
Rosiglitazone may increase vascular leakage in insulin-treated patients with type 2 diabetes with autonomic neuropathy. Autonomic neuropathy did not exaggerate rosiglitazone-induced fluid retention. Therefore, autonomic neuropathy should be considered as a risk factor for thiazolidinedione-induced oedema, not for thiazolidinedione-induced fluid retention.
Trial registration NCT00422955
PMCID: PMC2910895  PMID: 20499046
Autonomic neuropathy; Clinical science; Diabetes mellitus; Human; Oedema; Oral pharmacological agents; Randomised controlled trial; Risk factors; Thiazolidinediones
11.  Carotid Intima Media Thickness, Inflammatory Markers, and Endothelial Activation Markers in HIV Patients with Lipoatrophy Increased at 48 Weeks Regardless of Use of Rosiglitazone or Placebo 
Rosiglitazone may be useful for the treatment of antiretroviral therapy-associated lipoatrophy, but an association with cardiovascular disease (CVD) has been questioned in diabetics. We evaluated rosiglitazone's effect on surrogate markers of CVD in HIV-infected individuals with lipoatrophy. HIV+ patients with lipoatrophy on thymidine-sparing regimens were randomized to rosiglitazone vs. placebo for 48 weeks. We serially assessed carotid IMT, fasting metabolic profiles, tumor necrosis factor (TNF)-α, soluble receptors (sTNFRI and II), interleukin (IL)-6, high-sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO), and endothelial activation markers [von Willebrand factor (vWF), soluble intercellular cell adhesion molecules-1 (sICAM-1), and vascular cell adhesion molecules-1 (sVCAM-1)]. Seventy-one subjects enrolled: 17% were female and 51%were white. Baseline characteristics were similar between groups except for higher total cholesterol in the placebo group (p = 0.04). At 48 weeks, common carotid artery (CCA) IMT changed significantly (p ≤ 0.05) within but not between the groups (p = 0.36): the median (IQR) increase was 0.10 (0.05, 0.25) mm and 0.15 (0, 0.25) mm in the rosiglitazone and placebo groups, respectively. hsCRP, sTNFRI and II, sVCAM-1, and vWF changed significantly (p ≤ 0.02) within but not between groups. Total cholesterol increased significantly in the rosiglitazone group (p = 0.008). In our study of virologically controlled subjects with lipoatrophy, rosiglitazone did not independently increase carotid IMT, endothelial activation, and inflammatory cytokines.
PMCID: PMC3064528  PMID: 20969457
12.  Evidence from studies in rodents and in isolated adipocytes that agonists of the chemerin receptor CMKLR1 may be beneficial in the treatment of type 2 diabetes 
PeerJ  2015;3:e753.
The literature is unclear on whether the adipokine chemerin has pro- or anti-inflammatory properties or plays any role in the aetiology of type 2 diabetes or obesity. To address these questions, and in particular the potential of agonists or antagonists of the chemerin receptor CMKLR1 in the treatment of type 2 diabetes and obesity, we studied the metabolic phenotypes of both male and female, CMKLR1 knockout and heterozygote mice. We also investigated changes in plasma chemerin levels and chemerin gene mRNA content in adipose tissue in models of obesity and diabetes, and in response to fasting or administration of the insulin sensitizing drug rosiglitazone, which also has anti-inflammatory properties. The effects of murine chemerin and specific C-terminal peptides on glucose uptake in wild-type and CMKLR1 knockout adipocytes were investigated as a possible mechanism by which chemerin affects the blood glucose concentration. Both male and female CMKLR1 knockout and heterozygote mice displayed a mild tendency to obesity and impaired glucose homeostasis, but only when they were fed on a high-fat died, rather than a standard low-fat diet. Obesity and impaired glucose homeostasis did not occur concurrently, suggesting that obesity was not the sole cause of impaired glucose homeostasis. Picomolar concentrations of chemerin and its C15- and C19-terminal peptides stimulated glucose uptake in the presence of insulin by rat and mouse wild-type epididymal adipocytes, but not by murine CMKLR1 knockout adipocytes. The insulin concentration-response curve was shifted to the left in the presence of 40 pM chemerin or its C-15 terminal peptide. The plasma chemerin level was raised in diet-induced obesity and ob/ob but not db/db mice, and was reduced by fasting and, in ob/ob mice, by treatment with rosiglitazone. These findings suggest that an agonist of CMKLR1 is more likely than an antagonist to be of value in the treatment of type 2 diabetes and to have associated anti-obesity and anti-inflammatory activities. One mechanism by which an agonist of CMKLR1 might improve glucose homeostasis is by increasing insulin-stimulated glucose uptake by adipocytes.
PMCID: PMC4327305
Type 2 diabetes; Glucose uptake; Chemerin receptor; Adipocyte; Obesity; Chemerin; Rosiglitazone
13.  KDT501, a Derivative from Hops, Normalizes Glucose Metabolism and Body Weight in Rodent Models of Diabetes 
PLoS ONE  2014;9(1):e87848.
We developed KDT501, a novel substituted 1,3-cyclopentadione chemically derived from hop extracts, and evaluated it in various in vitro and in vivo models of diabetes and insulin sensitivity.
KDT501 was evaluated for anti-inflammatory effects in monocyte/macrophage cells; agonistic activity for peroxisome proliferator-activated receptors (PPAR); lipogenesis and gene expression profile in human subcutaneous adipocytes. Body composition, glucose, insulin sensitivity, and lipids were assessed in diet-induced obesity (DIO) mice and Zucker Diabetic Fatty (ZDF) rats after oral administration.
KDT501 mediated lipogenesis in 3T3L1 and human subcutaneous adipocytes; however, the gene expression profile of KDT501 differed from that of the full PPARγ agonist rosiglitazone, suggesting that KDT501 has pleiotropic biological activities. In addition, KDT501 showed only modest, partial PPARγ agonist activity and exhibited anti-inflammatory effects in monocytes/macrophages that were not observed with rosiglitazone. In a DIO mouse model, oral administration of KDT501 significantly reduced fed blood glucose, glucose/insulin AUC following an oral glucose bolus, and body fat. In ZDF rats, oral administration of KDT501 significantly reduced fed glucose, fasting plasma glucose, and glucose AUC after an oral glucose bolus. Significant, dose-dependent reductions of plasma hemoglobin A1c, weight gain, total cholesterol, and triglycerides were also observed in animals receiving KDT501.
These results indicate that KDT501 produces a unique anti-diabetic profile that is distinct in its spectrum of pharmacological effects and biological mechanism from both metformin and pioglitazone. KDT501 may thus constitute a novel therapeutic agent for the treatment of Type 2 diabetes and associated conditions.
PMCID: PMC3907559  PMID: 24498211
14.  High-Sensitivity C-Reactive Protein Predicts Cardiovascular Risk in Diabetic and Nondiabetic Patients: Effects of Insulin-Sensitizing Treatment with Pioglitazone 
Systemic inflammatory activity has turned out to play a key pathogenic role in vascular atherosclerosis, insulin resistance, and type 2 diabetes mellitus. Inflammatory biomarkers may therefore be a valuable tool for risk evaluation. Among them, the best evidence to date supports the use of high-sensitivity C-reactive protein (hs-CRP) to monitor insulin resistance and cardiovascular risk in diabetic and nondiabetic individuals. Data suggest that hs-CRP may also participate directly in the process of atherogenesis. A growing number of clinical trials tested the hypothesis that antidiabetic drugs specifically targeting insulin resistance could benefit individuals by reducing inflammation, atherogenesis, and thus cardiovascular risk. One such class are the thiazolidinediones (pioglitazone and rosiglitazone). These agents act as selective ligands of the nuclear transcription factor peroxisome proliferator-activated receptor-γ (PPARγ). This article reviewed published data on hs-CRP changes with the thiazolidinedione agent pioglitazone. Here we found pronounced insulin-sensitizing and anti-inflammatory properties in different clinical settings, including diabetic and nondiabetic individuals. Coadministration of pioglitazone to antilipidemic statin therapy resulted in additional effects on low-grade inflammation, and hs-CRP reduction has been demonstrated to occur independently of glucose lowering. The anti-inflammatory effect appeared to be a rapid physiologic reaction on PPARγ activation and could be observed within a short-term interval after starting pioglitazone therapy. In summary, clinical study results underline the benefit of an early insulin resistance treatment to oppose systemic vascular inflammation and cardiometabolic syndrome in patients with elevated levels of high-sensitivity C-reactive protein.
PMCID: PMC2901049  PMID: 20513338
atherosclerosis; diabetes; hs-CRP; inflammation; insulin resistance; pioglitazone
15.  Plasma adipokine and inflammatory marker concentrations are altered in obese, as opposed to non-obese, type 2 diabetes patients 
Elevated plasma free fatty acid (FFA), inflammatory marker, and altered adipokine concentrations have been observed in obese type 2 diabetes patients. It remains unclear whether these altered plasma concentrations are related to the diabetic state or presence of obesity. In this cross-sectional observational study, we compare basal plasma FFA, inflammatory marker, and adipokine concentrations between obese and non-obese type 2 diabetes patients and healthy, non-obese controls. A total of 20 healthy, normoglycemic males (BMI <30 kg/m2), 20 non-obese (BMI <30 kg/m2) and 20 obese (BMI >35 kg/m2) type 2 diabetes patients were selected to participate in this study. Groups were matched for age and habitual physical activity level. Body composition, glycemic control, and exercise performance capacity were assessed. Basal blood samples were collected to determine plasma leptin, adiponectin, resistin, tumor necrosis factor α (TNFα), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP) and FFA concentrations. Plasma FFA, inflammatory marker (hsCRP, IL-6, TNFα), adipokine (adiponectin, resistin, leptin), and triglyceride concentrations did not differ between non-obese diabetes patients and healthy, normoglycemic controls. Plasma FFA, IL-6, hsCRP, leptin, and triglyceride levels were significantly higher in the obese diabetes patients when compared with the healthy normoglycemic controls (P < 0.05). Furthermore, plasma hsCRP and leptin levels were significantly higher in the obese versus non-obese diabetes patients (P < 0.05). Significant correlations between plasma parameters and glycemic control were observed, but disappeared after adjusting for trunk adipose tissue mass. Elevated plasma leptin, hsCRP, IL-6, and FFA concentrations are associated with obesity and not necessarily with the type 2 diabetic state.
PMCID: PMC2874484  PMID: 20131064
Obesity; Diabetes; Adipokines; Inflammation; Fat mass
16.  Rosiglitazone activation of PPARγ suppresses fractalkine signaling 
The nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) is a key transcriptional regulator of both lipid metabolism and inflammation. The importance of PPARγ is accentuated by the widespread use of synthetic PPARγ agonists, thiazolidinediones (such as rosiglitazone), as drugs for insulin resistance and type II diabetes. Fractalkine (FKN) and FKN receptor (FR) play an important role in the immune responses by regulating leukocyte migration and adhesion to inflamed peripheral tissues. In this study, we have identified a novel link between PPARγ activation and FKN signaling. On one hand, the activation of PPARγ by rosiglitazone in macrophages not only represses the transcription of the FR gene, but also prevents the plasma membrane translocation of the FR protein. On the other hand, the activation of PPARγ by rosiglitazone in endothelial cells also impedes the nuclear export of FKN. Together, these data suggest that PPARγ activation represses FKN signaling. These findings indicate a previously unrecognized mechanism that may contribute to the anti-inflammatory effect of PPARγ.
PMCID: PMC2805405  PMID: 19850645
17.  Vasculoprotective effects of rosiglitazone through modulating renin-angiotensin system in vivo and vitro 
The peroxisome proliferator-activated receptor-γ (PPARγ) agonist rosiglitazone has been suggested to exert cardiovascular protection through the improvement of lipid metabolism, anti-inflammation, anti-proliferation etc. However, whether renin-angiotensin system (RAS) is involved in the vascular protective effects of PPARγ agonists is not fully understood. The present study aimed to investigate the effects of the renin-angiotensin system in vascular protection mediated by PPARγ agonists.
To investigate the actions of the renin-angiotensin system in vascular protection mediated by activation of PPARγ in vivo and in vitro.
Rats were fed a regular diet (n = 8), a cholesterol-rich diet plus methylthiouracil (80 mg/Kg/day, n = 10), a cholesterol-rich diet plus methylthiouracil and rosiglitazone (4 mg/kg/day, n = 10). The rosiglitazone treatment was started from one month after the start of cholesterol-rich diet plus methylthiouracil, and lasted five months. Cultured vascular smooth muscle cells (VSMCs) were pretreated with 1 μmol/L angiotensin II (ANG II) for 6 h and randomly divided into the control group; the ANG II group (1 μmol/L ANG II); the groups respectively treated with different concentration rosiglitazone (20, 30, 50) μmol/L for 12 h; the groups treated with 30 μmol/L rosiglitazone for (6, 12, 24) h. Morphology changes of the aortic tissues were observed by hematoxylin and eosin stain. The VSMC growth was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. Angiotensin II and expression of angiotensin receptors were determined by radioimmunoassay, reverse transcription polymerase chain reaction (RT-PCR), western blot, and immunohistochemistry.
After 6 months, lipid deposition, VSMC proliferation and migration toward intima were observed in aortic tissues in the rats on a cholesterol-rich diet plus methylthiouracil, while these pathological changes induced by the cholesterol-rich diet were significantly suppressed by rosiglitazone. In addition, VSMC proliferation induced by ANG II was markedly inhibited by rosiglitazone. Rosiglitazone markedly down-regulated expression of angiotensin type 1 receptor (AT1R) and up-regulated expression of angiotensin type 2 receptor (AT2R) in the aortic tissues and ANG II-treated VSMCs.
The present study demonstrated that PPARγ agonist rosiglitazone suppressed ANG II-induced VSMC proliferation in vitro and early atherosclerotic formation evoked by cholesterol-rich diet in vivo. These vasculoprotective effects of rosiglitazone were mediated at least partially by reduction in local tissue ANG II concentration, down-regulation of AT1R expression and up-regulation of AT2R expression both at the mRNA and protein levels.
PMCID: PMC3039565  PMID: 21269478
18.  A randomized, controlled trial of the effects of rosiglitazone on adipokines, and inflammatory and fibrinolytic markers in diabetic patients: Study design and protocol 
The Canadian Journal of Cardiology  2008;24(10):e65-e69.
Although rosiglitazone may offer vascular benefits beyond lowering glucose, recently, concern has been raised that this drug may paradoxically increase cardiovascular risk.
To assess the effects of rosiglitazone compared with standard oral hypoglycemic therapies on adipokines, and inflammatory and fibrinolytic markers in subjects with type 2 diabetes.
A 12-week, randomized, open-label, parallel-group study will be conducted on 100 type 2 diabetic subjects with suboptimal glycemic control (glycosylated hemoglobin 0.075 or greater) despite management with lifestyle alone (drug-naive) or with monotherapy (either metformin or sulfonylurea). Drug-naive patients will be randomly assigned to receive either rosiglitazone (4 mg/day to 8 mg/day) or metformin (500 mg/day to 2000 mg/day). Patients on pre-existing monotherapy will be randomly assigned to the addition of rosiglitazone (4 mg/day to 8 mg/day), or to either metformin (500 mg/day to 2000 mg/day) or glyburide (5 mg/day to 20 mg/day) (depending on background treatment). The primary end point of the study is the change in adiponectin level (from baseline to 12 weeks) in the rosiglitazone versus metformin or sulfonylurea arms. Secondary end points include changes in leptin, high-sensitivity C-reactive protein, interleukin-6, tumour necrosis factor-alpha, matrix metalloproteinase-9, vascular cell adhesion molecule-1, plasminogen activator inhibitor type 1, insulin sensitivity, glycosylated hemoglobin and lipid levels. Additionally, all patients will be required to be treated with an inhibitor of the renin-angiotensin system, namely an angiotensin receptor antagonist, as per national diabetes treatment guidelines, to a target systolic blood pressure of less than 130 mmHg and a diastolic blood pressure of less than 80 mmHg, or for the optimal suppression of microalbuminuria.
The present study will further elucidate the potential beneficial metabolic and cardiovascular effects of rosiglitazone in optimally treated diabetic patients.
PMCID: PMC2643164  PMID: 18841263
Cardiometabolic risk; Inflammation; Thiazolidinediones; Type 2 diabetes
19.  PPAR Agonist-Induced Reduction of Mcp1 in Atherosclerotic Plaques of Obese, Insulin-Resistant Mice Depends on Adiponectin-Induced Irak3 Expression 
PLoS ONE  2013;8(4):e62253.
Synthetic peroxisome proliferator-activated receptor (PPAR) agonists are used to treat dyslipidemia and insulin resistance. In this study, we examined molecular mechanisms that explain differential effects of a PPARα agonist (fenofibrate) and a PPARγ agonist (rosiglitazone) on macrophages during obesity-induced atherogenesis. Twelve-week-old mice with combined leptin and LDL-receptor deficiency (DKO) were treated with fenofibrate, rosiglitazone or placebo for 12 weeks. Only rosiglitazone improved adipocyte function, restored insulin sensitivity, and inhibited atherosclerosis by decreasing lipid-loaded macrophages. In addition, it increased interleukin-1 receptor-associated kinase-3 (Irak3) and decreased monocyte chemoattractant protein-1 (Mcp1) expressions, indicative of a switch from M1 to M2 macrophages. The differences between fenofibrate and rosiglitazone were independent of Pparγ expression. In bone marrow-derived macrophages (BMDM), we identified the rosiglitazone-associated increase in adiponectin as cause of the increase in Irak3. Interestingly, the deletion of Irak3 in BMDM (IRAK3−/− BMDM) resulted in activation of the canonical NFκB signaling pathway and increased Mcp1 protein secretion. Rosiglitazone could not decrease the elevated Mcp1 secretion in IRAK3−/− BMDM directly and fenofibrate even increased the secretion, possibly due to increased mitochondrial reactive oxygen species production. Furthermore, aortic extracts of high-fat insulin-resistant LDL-receptor deficient mice, with lower adiponectin and Irak3 and higher Mcp1, showed accelerated atherosclerosis. In aggregate, our results emphasize an interaction between PPAR agonist-mediated increase in adiponectin and macrophage-associated Irak3 in the protection against atherosclerosis by PPAR agonists.
PMCID: PMC3631170  PMID: 23620818
20.  The effects of pentoxifylline administration on NFΚB P50 transcription factor expression 
ARYA Atherosclerosis  2012;7(4):133-137.
Pentoxifylline has anti-inflammatory properties and could suppress some inflammatory processes including tumor necrosis factor-alpha (TNF-α) production. We assessed the effects of a two-month administration of pentoxifylline on nuclear factor-kappa B (NFκB) pathways in patients with coronary artery disease (CAD) in which inflammatory pathways, especially NFκB transcription factors, have a critical role.
A double-blind randomized placebo-controlled study design was used. Forty CAD patients were randomized to either 2 months of pentoxifylline treatment (1200 mg/day) (n = 20) or placebo treatment (n = 20). Blood samples were obtained just before and after two months of treatment. P50 protein concentration in peripheral blood mononuclear cells (PBMCs) was measured by Enzyme Linked ImmunoSorbent Assay (ELISA) method.
P50 concentration did not significantly change during two months of pentoxifylline administration.
Longer pentoxifylline administration is needed to see its favorable effects on NFκB family elements.
PMCID: PMC3413080  PMID: 23205044
Coronary Artery Diseases; Inflammation; NFκB; Pentoxifylline
21.  Improvement of abnormal liver enzymes after rosiglitazone treatment in Chinese type 2 diabetes 
Indian Journal of Pharmacology  2012;44(3):372-376.
Insulin resistance is one of the important underlying abnormalities of type 2 diabetes. The effect of thiazolidinedione on liver functions has been controversial in different studies. In this study, we evaluated the effect of rosiglitazone on liver enzymes in subjects with type 2 diabetes with and without abnormal liver function.
Materials and Methods:
Seventy-three patients with type 2 diabetes taking rosiglitazone 4 mg daily were enrolled in this 3-month study. Forty-two of them had normal liver function (NLF), and 31 had abnormal liver function (ABLF). Blood biochemistries were collected monthly during the treatment period.
At baseline, other than age and liver enzymes, there were no differences in body mass index, fasting plasma glucose, hemoglobin A1c (HbA1c), and lipid profiles between the NLF and ABLF groups. At the end of the treatment, HbA1c was lowered in both groups, but only significantly in the ABLF group (P = 0.027). More importantly, serum concentrations of both aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the ABLF group decreased significantly (AST: 57.8 ± 26.5 to 47.5 ± 20.2 U/L, P = 0.006; ALT 66.6 ± 35.0 to 51.9 ± 23.5 UL, P = 0.004), while in the NLF group, a similar change was not found.
After 3-month rosiglitazone treatment in subjects with type 2 diabetes with mildly elevated liver enzymes, significant improvement in AST and ALT were observed. Our study provides some hints that rosiglitazone might not be contraindicated in subjects with diabetes with abnormal liver function as previously thought, but further well-designed studies are necessary to clarify this issue.
PMCID: PMC3371462  PMID: 22701249
Rosiglitazone; type 2 diabetes; liver function
22.  Changes in endotoxin levels in T2DM subjects on anti-diabetic therapies 
Chronic low-grade inflammation is a significant factor in the development of obesity associated diabetes. This is supported by recent studies suggesting endotoxin, derived from gut flora, may be key to the development of inflammation by stimulating the secretion of an adverse cytokine profile from adipose tissue.
The study investigated the relationship between endotoxin and various metabolic parameters of diabetic patients to determine if anti-diabetic therapies exerted a significant effect on endotoxin levels and adipocytokine profiles.
Fasting blood samples were collected from consenting Saudi Arabian patients (BMI: 30.2 ± (SD)5.6 kg/m2, n = 413), consisting of non-diabetics (ND: n = 67) and T2DM subjects (n = 346). The diabetics were divided into 5 subgroups based on their 1 year treatment regimes: diet-controlled (n = 36), metformin (n = 141), rosiglitazone (RSG: n = 22), a combined fixed dose of metformin/rosiglitazone (met/RSG n = 100) and insulin (n = 47). Lipid profiles, fasting plasma glucose, insulin, adiponectin, resistin, TNF-α, leptin, C-reactive protein (CRP) and endotoxin concentrations were determined.
Regression analyses revealed significant correlations between endotoxin levels and triglycerides (R2 = 0.42; p < 0.0001); total cholesterol (R2 = 0.10; p < 0.001), glucose (R2 = 0.076; p < 0.001) and insulin (R2 = 0.032; p < 0.001) in T2DM subjects. Endotoxin showed a strong inverse correlation with HDL-cholesterol (R2 = 0.055; p < 0.001). Further, endotoxin levels were elevated in all of the treated diabetic subgroups compared with ND, with the RSG treated diabetics showing significantly lower endotoxin levels than all of the other treatment groups (ND: 4.2 ± 1.7 EU/ml, RSG: 5.6 ± 2.2 EU/ml). Both the met/RSG and RSG treated groups had significantly higher adiponectin levels than all the other groups, with the RSG group expressing the highest levels overall.
We conclude that sub-clinical inflammation in T2DM may, in part, be mediated by circulating endotoxin. Furthermore, that whilst the endotoxin and adipocytokine profiles of diabetic patients treated with different therapies were comparable, the RSG group demonstrated significant differences in both adiponectin and endotoxin levels. We confirm an association between endotoxin and serum insulin and triglycerides and an inverse relationship with HDL. Lower endotoxin and higher adiponectin in the groups treated with RSG may be related and indicate another mechanism for the effect of RSG on insulin sensitivity.
PMCID: PMC2674418  PMID: 19368716
23.  Activation of nuclear factor κB in inflammatory bowel disease 
Gut  1998;42(4):477-484.
Background—Expression of pro-inflammatory cytokines is increased in the intestinal lamina propria of patients with inflammatory bowel disease (IBD). Nuclear factor κB (NFκB) controls transcription of inflammation genes. On activation, NFκB is rapidly released from its cytoplasmic inhibitor (IκB), transmigrates into the nucleus, and binds to DNA response elements in gene promoter regions. 
Aims—To investigate whether increased activation of NFκB is important in IBD and may be down-regulated by anti-inflammatory treatment. 
Methods—Activation of NFκB was determined by western blot assessment and electrophoretic mobility shift assay in nuclear extracts of colonic biopsy samples as well as lamina propria mononuclear cells. 
Results—Nuclear levels of NFκB p65 are increased in lamina propria biopsy specimens from patients with Crohn's disease in comparison with patients with ulcerative colitis and controls. Increased activation of NFκB was detected in lamina propria mononuclear cells from patients with active IBD. Corticosteroids strongly inhibit intestinal NFκB activation in IBD in vivo and in vitro by stabilising the cytosolic inhibitor IκBα against activation induced degradation. 
Conclusions—In both IBDs, but particularly Crohn's disease, increased activation of NFκB may be involved in the regulation of the inflammatory response. Inhibition of NFκB activation may represent a mechanism by which steroids exert an anti-inflammatory effect in IBD. 

Keywords: interleukin 1ß; inflammatory bowel disease; intestinal immunity; signal transduction; steroids; tumour necrosis factor α
PMCID: PMC1727068  PMID: 9616307
24.  Thiazolidinediones are Partial Agonists for the Glucocorticoid Receptor 
Endocrinology  2008;150(1):75-86.
Although thiazolidinediones were designed as specific PPARγ-ligands there is evidence for some off-target effects mediated by a non-PPARγ mechanism. Previously we have shown that Rosiglitazone has anti-inflammatory actions not explicable by activation of PPARγ, but possibly by the glucocorticoid receptor (GR).
Rosiglitazone induces nuclear translocation both of GR-GFP, and endogenous GR in HeLa and U20S cells but with slower kinetics than Dexamethasone. Rosiglitazone also induces GR phosphorylation (Ser211), a GR ligand-binding specific effect.
Rosiglitazone drives luciferase expression from a simple GRE containing reporter gene in a GR-dependent manner (EC50 4μM), with a similar amplitude response to the partial GR agonist RU486. Rosiglitazone also inhibits Dexamethasone driven reporter gene activity (IC50 2.9μM) in a similar fashion to RU486, suggesting partial agonist activity. Importantly we demonstrate a similar effect in PPARγ-null cells suggesting both GR-dependence and PPARγ-independence.
Rosiglitazone also activates a GAL4-GR chimera, driving a UAS promoter, demonstrating DNA template sequence independence, and furthermore enhanced SRC1-GR interaction, measured by a mammalian two-hybrid assay.
Both Ciglitazone and Pioglitazone, structurally related to Rosiglitazone, show similar effects on the GR.
The antiproliferative effect of Rosiglitazone is increased in U20S cells that overexpress GR, suggesting a biologically important GR-dependent component of Rosiglitazone action.
Rosiglitazone is a partial GR agonist, affecting GR activation and trafficking to influence engagement of target genes and affect cell function. This novel mode of action may explain some off-target effects observed in vivo. Additionally, antagonism of glucocorticoid action may contribute to the anti-diabetic actions of Rosiglitazone.
PMCID: PMC4110506  PMID: 18801908
Rosiglitazone; Glucocorticoids; Glucocorticoid Receptor; PPARγ; Diabetes
25.  Oral Administration of Nano-Emulsion Curcumin in Mice Suppresses Inflammatory-Induced NFκB Signaling and Macrophage Migration 
PLoS ONE  2014;9(11):e111559.
Despite the widespread use of curcumin for centuries in Eastern medicine as an anti-inflammatory agent, its molecular actions and therapeutic viability have only recently been explored. While curcumin does have potential therapeutic efficacy, both solubility and bioavailability must be improved before it can be more successfully translated to clinical care. We have previously reported a novel formulation of nano-emulsion curcumin (NEC) that achieves significantly greater plasma concentrations in mice after oral administration. Here, we confirm the immunosuppressive effects of NEC in vivo and further examine its molecular mechanisms to better understand therapeutic potential. Using transgenic mice harboring an NFκB-luciferase reporter gene, we demonstrate a novel application of this in vivo inflammatory model to test the efficacy of NEC administration by bioluminescent imaging and show that LPS-induced NFκB activity was suppressed with NEC compared to an equivalent amount of curcumin in aqueous suspension. Administration of NEC by oral gavage resulted in a reduction of blood monocytes, decreased levels of both TLR4 and RAGE expression, and inhibited secretion of MCP-1. Mechanistically, curcumin blocked LPS-induced phosphorylation of the p65 subunit of NFκB and IκBα in murine macrophages. In a mouse model of peritonitis, NEC significantly reduced macrophage recruitment, but not T-cell or B-cell levels. In addition, curcumin treatment of monocyte derived cell lines and primary human macrophages in vitro significantly inhibited cell migration. These data demonstrate that curcumin can suppress inflammation by inhibiting macrophage migration via NFκB and MCP-1 inhibition and establish that NEC is an effective therapeutic formulation to increase the bioavailability of curcumin in order to facilitate this response.
PMCID: PMC4219720  PMID: 25369140

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